lwIP 2.1.3 Lightweight IP stack

Changelog

## 2.1.0

- Support TLS via new Application layered TCP Introduction connection API (https, smtps, mqtt over TLS)
- Switch to cmake as the main build system (Makefile file lists are still maintained for now)
- Improve IPv6 support: support address scopes, support stateless DHCPv6, bugfixes
- Add debug helper asserts to ensure threading/locking requirements are met
- Add sys_mbox_trypost_fromisr() and tcpip_callbackmsg_trycallback_fromisr() (for FreeRTOS, mainly)
- socket API: support poll(), sendmsg() and recvmsg(); fix problems on close

## Detailed Changelog

    HISTORY
     * These are only the most important changes. For a full list, use git log:
       http://git.savannah.nongnu.org/cgit/lwip.git

    (git master)

      * [Enter new changes just after this line - do not remove this line]

    (STABLE-2.1.2):

      ++ Bugfixes:

      2018-11-21: Jens Nielsen
      * netbiosns.c: fix expecting too large packet (bug #55069)

      2018-11-19: Dirk Ziegelmeier
      * smtp.c: fix compiling with strict C compatibility because of strnlen (bug #55034)

      2018-11-12: Simon Goldschmidt
      * tcp.c: fix overflow check in tcp_recved triggering invalid assertion (bug #55015)

      2018-11-12: Simon Goldschmidt
      * tcp.c: fix a bug in sending RST segments (sent from port 0)

    (STABLE-2.1.1):

      ++ Bugfixes:

      2018-11-01: Joan Lledó
      * sockets.c: fix bad assertion in lwip_poll_dec_sockets_used() (bug #54933)

      2018-11-01: Dirk Ziegelmeier
      * ip4.c: don't send 127.* to default netif (bug #54670)

      2018-10-23: David Girault
      * altcp_tls_mbedtls.c: fix use-after free (bug #54774)

      2018-10-23: Ognjen Bjelica, Dirk Ziegelmeier
      * snmp_scalar.c: Avoid NULL pointer dereference (bug #54886)

      2018-10-23: Simon Goldschmidt
      * Fix missing standard includes in multiple files

      2018-10-17: Ivan Warren
      * def.h: fix casting htonX and ntohX to u16_t (bug #54850)

      2018-10-12: Simon Goldschmidt
      * Revert "tcp_abandon: no need to buffer pcb->local_port" (fix that source port was 0 for RST
        called when aborting a connection)

      2018-10-11: Jonas Rabenstein
      * tcp.c: tcp_recved: check for overflow and warn about too big values (patch #9699)

      2018-10-06: Joan Lledó
      * sockets.c: alloc_socket(): Check for LWIP_SOCKET_POLL when setting select-
        related variables (patch #9696)

      2018-10-04: Spencer
      * tcp.c: Update prev pointer when skipping entries in tcp_slowtmr (patch #9694)

      2018-09-27: Martine Lenders
      * lowpan6.c: Fix IEEE 802.15.4 address setting (bug #54749)

    (STABLE-2.1.0):

      ++ New features:

      2018-06-17: Simon Goldschmidt
      * lwiperf: implemented iPerf client mode

      2018-04-23: Dirk Ziegelmeier
      * added cmake build files

      2018-03-04: Ray Abram
      * netbios responder: respond to '*' queries

      2018-02-23: Benjamin Aigner
      * 6lowpan: add 6lowpan-over-BLE netif (based on existing 6lowpan netif)

      2018-02-22: Simon Goldschmidt
      * ipv6: add support for stateless DHCPv6 (to get DNS servers in SLAAC nets)

      2018-02-16: Simon Goldschmidt
      * add raw API http(s) client (with proxy support)

      2018-02-01: Simon Goldschmidt
      * tcp: add hooks to implement additional socket options

      2018-02-01: Simon Goldschmidt
      * tcp: add hooks to implement tcp md5 signatures or similar (see contrib/addons for an example)

      2018-01-05: Simon Goldschmidt
      * Added sys_mbox_trypost_fromisr() and tcpip_callbackmsg_trycallback_fromisr()
        These can be used to post preallocated messages from an ISR to the tcpip thread
        (e.g. when using FreeRTOS)

      2018-01-02: Dirk Ziegelmeier
      * task #14780: Add debug helper asserts to ensure threading/locking requirements are met

      2017-11-21: Simon Goldschmidt
      * task #14600: tcp_alloc(): kill TF_CLOSEPEND connections before other ESTABLISHED

      2017-11-21: Simon Goldschmidt
      * makefsdata: added option "-ssi:<filename>" to control SSI tag checking/insertion
        through a list of filenames, not by checking the file extension at runtime

      2017-11-20: Joel Cunningham
      * netconn: add LWIP_HOOK_NETCONN_EXTERNAL_RESOLVE to use external DNS resolver (patch #9427)

      2017-11-14: Joel Cunningham
      * netifapi: Add thread safe ARP cache APIs (task #14724)

      2017-11-06: Axel Lin
      * TCP: kill existing connections with a LOWER priority than the one currently being opened.
        Previous implementations also kill existing connections of the SAME priority.

      2017-09-21: Kalle Olavi Niemitalo
      * sockets: add poll() implementation (patch #9450)

      2017-09-10: Joel Cunningham
      * sockets: add readv() implementation (task #14610)

      2017-08-04: Simon Goldschmidt
      * Clean up DHCP a bit: no need keep msg_out and msg_in as members in struct
        dhcp - they are used in a call stack only (p_out and options_out_len as well)

      2017-08-04: Simon Goldschmidt
      * pbuf: split pbuf_header(s16_t) into pbuf_add_header(size_t) and
        pbuf_remove_header(size_t)

      2017-07-20: Douglas
      * sys: deprecate sys_arch_sem_wait and sys_arch_mbox_fetch returning the
        time waited rather they are now defined to return != SYS_ARCH_TIMEOUT
        on success.

      2017-07-03: Jakub Schmidtke
      * tcp: added support for sending TCP SACKs

      2017-06-20: Joel Cunningham
      * netconn/netdb: added core locking support to netconn_gethostbyname (task #14523)

      2017-04-25: Simon Goldschmidt
      * dhcp: added two hooks for adding and parsing user defined DHCP options

      2017-04-25: Joel Cunningham
      * sockets: added recvmsg for UDP (together with CMSG and IP_PKTINFO) (task #14247)

      2017-04-20: Joel Cunningham
      * tcp: added Appropriate Byte Counting support (task #14128)

      2017-04-11: Simon Goldschmidt
      * netconn/sockets: remove fatal error handling, fix asynchronous error handling,
        ensure data before RST can be received

      2017-03-30: Simon Goldschmidt
      * added "application layered TCP" connection API (altcp) for seamless integration
        of TLS or proxy connections

      2017-03-09: Simon Goldschmidt
      * sockets: add recvmsg for TCP

      2017-03-02: Joel Cunningham
      * netconn/sockets: vectorize netconn_write for TCP, treating a vectored I/O write
        atomically in regards to TCP segmentation (patch #8882)

      2017-03-02: Simon Goldschmidt
      * netconn: added nonblocking accept/recv to netconn API (task #14396)

      2017-02-28: Simon Goldschmidt
      * Added LWIP_SINGLE_NETIF for small targets with only one netif

      2017-02-10: David van Moolenbroek
      * Implement UDP and RAW multicast support for IPv6 (core API, not netconn/sockets)

      2017-02-04: David van Moolenbroek
      * IPv6 scopes support

      2017-01-20: Joel Cunningham
      * sockets: add interface name/index APIs (task #14314)

      2017-01-08: David van Moolenbroek
      * Extensions to RAW API (patch #9208)
        - Connected RAW PCBs
        - Add raw_sendto_if_src()
        - Support IP_HDRINCL socket option

      ++ Bugfixes:

      2018-06-19: Simon Goldschmidt
      * tcp: fix RTO timer not working if link is down

      2018-06-15: Sylvain Rochet
      * ppp: multiple smaller bugfixes

      2018-05-17: Simon Goldschmidt
      * etharp: arp table can now be bigger than 127 entries

      2018-04-25: Jens Nielsen
      * tftp server: correctly handle retransmissions

      2018-04-18: Simon Goldschmidt
      sockets: fix race conditions when closing full-duplex sockets

      2018-03-09: Simon Goldschmidt
      * 6lowpan: fix to work against contiki; added ZigBee encapsulation netif for tests

      2018-02-04: Simon Goldschmidt
      * sockets: fix inconsistencies on close (inconsistent error codes, double FIN)

      2018-01-05: Dirk Ziegelmeier
      * Fix bug #52748: the bug in timeouts.c by reimplementing timer logic to use
        absolute instead of relative timeout values

      2017-12-31: Dirk Ziegelmeier
      * Fix bug #52704: DHCP and bad OFFER: Stop timeout only if offer is accepted

      2017-11-08: Joel Cunningham
      * netif: ensure link and admin states are up in issue reports (bug #52353)

      2017-09-12: David Lockyer
      * select: allocate select_cb from memp for LWIP_MPU_COMPATIBLE = 1 (bug #51990)

      2017-09-11: Simon Goldschmidt
      * tcp_in.c: fix bug #51937 (leaking tcp_pcbs on passive close with unacked data)

      2017-08-11: Joel Cunningham
      * lwip_itoa: fix converting the number 0 (previously converted to '\0') (bug #51729)

      2017-08-08: Dirk Ziegelmeier
      * ip4_route_src: parameter order is reversed: ip4_route_src(dest, src) -> ip4_route_src(src, dest)
        to make parameter order consistent with other ip*_route*() functions
        Same also applies to LWIP_HOOK_IP4_ROUTE_SRC() parameter order.

      2017-08-04: Joel Cunningham
      * tcp: re-work persist timer to fully close window (details in bug #50837)

      2017-07-26: Simon Goldschmidt
      * snmp_msg.c: fix bug #51578 (SNMP failed to decode some values on non 32bit platforms)

      2017-07-20: Simon Goldschmidt
      * compatibility headers: moved from 'src/include/posix' to 'src/include/compat/posix',
        'src/include/compat/stdc' etc.

      2017-05-09: Joel Cunningham
      * tcp: add zero-window probe timeout (bug #50837)

      2017-04-11: Simon Goldschmidt
      * sockets.c: task #14420 (Remove sys_sem_signal from inside SYS_ARCH_PROTECT
        crit section) done for LWIP_TCPIP_CORE_LOCKING==1

      2017-02-24: Simon Goldschmidt
      * sockets.c: fixed close race conditions in lwip_select (for LWIP_NETCONN_FULLDUPLEX)

      2017-02-24: Simon Goldschmidt
      * sockets.c: fixed that select ignored invalid/not open sockets in the fd_sets (bug #50392)

      2017-01-11: David van Moolenbroek
      * Lots of IPv6 related fixes and improvements

    (STABLE-2.0.3)

      ++ Bugfixes:

      2017-09-11: Simon Goldschmidt
      * tcp_in.c: fix bug #51937 (leaking tcp_pcbs on passive close with unacked data)

      2017-08-02: Abroz Bizjak/Simon Goldschmidt
      * multiple fixes in IPv4 reassembly (leading to corrupted datagrams received)

      2017-03-30: Simon Goldschmidt
      * dhcp.c: return ERR_VAL instead of asserting on offset-out-of-pbuf

      2017-03-23: Dirk Ziegelmeier
      * dhcp.h: fix bug #50618 (dhcp_remove_struct() macro does not work)

    (STABLE-2.0.2)

      ++ New features:

      2017-02-10: Dirk Ziegelmeier
      * Implement task #14367: Hooks need a better place to be defined:
        We now have a #define for a header file name that is #included in every .c
        file that provides hooks.

      2017-02-10: Simon Goldschmidt
      * tcp_close does not fail on memory error (instead, FIN is sent from tcp_tmr)

      ++ Bugfixes:

      2017-03-08
      * tcp: do not keep sending SYNs when getting ACKs

      2017-03-08: Joel Cunningham
      * tcp: Initialize ssthresh to TCP_SND_BUF (bug #50476)

      2017-03-01: Simon Goldschmidt
      * httpd: LWIP_HTTPD_POST_MANUAL_WND: fixed double-free when httpd_post_data_recved
        is called nested from httpd_post_receive_data() (bug #50424)

      2017-02-28: David van Moolenbroek/Simon Goldschmidt
      * tcp: fixed bug #50418: LWIP_EVENT_API: fix invalid calbacks for SYN_RCVD pcb

      2017-02-17: Simon Goldschmidt
      * dns: Improved DNS_LOCAL_HOSTLIST interface (bug #50325)

      2017-02-16: Simon Goldschmidt
      * LWIP_NETCONN_FULLDUPLEX: fixed shutdown during write (bug #50274)

      2017-02-13: Simon Goldschmidt/Dirk Ziegelmeier
      * For tiny targtes, LWIP_RAND is optional (fix compile time checks)

      2017-02-10: Simon Goldschmidt
      * tcp: Fixed bug #47485 (tcp_close() should not fail on memory error) by retrying
        to send FIN from tcp_fasttmr

      2017-02-09: Simon Goldschmidt
      * sockets: Fixed bug #44032 (LWIP_NETCONN_FULLDUPLEX: select might work on
        invalid/reused socket) by not allowing to reallocate a socket that has
        "select_waiting != 0"

      2017-02-09: Simon Goldschmidt
      * httpd: Fixed bug #50059 (httpd LWIP_HTTPD_SUPPORT_11_KEEPALIVE vs.
        LWIP_HTTPD_KILL_OLD_ON_CONNECTIONS_EXCEEDED)

      2017-02-08: Dirk Ziegelmeier
      * Rename "IPv6 mapped IPv4 addresses" to their correct name from RFC4191:
        "IPv4-mapped IPv6 address"

      2017-02-08: Luc Revardel
      * mld6.c: Fix bug #50220 (mld6_leavegroup does not send ICMP6_TYPE_MLD, even
        if last reporter)

      2017-02-08: David van Moolenbroek
      * ip6.c: Patch #9250: fix source substitution in ip6_output_if()

      2017-02-08: Simon Goldschmidt
      * tcp_out.c: Fixed bug #50090 (last_unsent->oversize_left can become wrong value
        in tcp_write error path)

      2017-02-02: Dirk Ziegelmeier
      * Fix bug #50206: UDP Netconn bind to IP6_ADDR_ANY fails

      2017-01-18: Dirk Ziegelmeier
      * Fix zero-copy RX, see bug bug #50064. PBUF_REFs were not supported as ARP requests.

      2017-01-15: Axel Lin, Dirk Ziegelmeier
      * minor bug fixes in mqtt

      2017-01-11: Knut Andre Tidemann
      * sockets/netconn: fix broken default ICMPv6 handling of checksums

    (STABLE-2.0.1)

      ++ New features:

      2016-12-31: Simon Goldschmidt
      * tcp.h/.c: added function tcp_listen_with_backlog_and_err() to get the error
        reason when listening fails (bug #49861)

      2016-12-20: Erik Andersen
      * Add MQTT client

      2016-12-14: Jan Breuer:
      * opt.h, ndc.h/.c: add support for RDNSS option (as per RFC 6106)

      2016-12-14: David van Moolenbroek
      * opt.h, nd6.c: Added LWIP_HOOK_ND6_GET_GW()

      2016-12-09: Dirk Ziegelmeier
      * ip6_frag.c: Implemented support for LWIP_NETIF_TX_SINGLE_PBUF

      2016-12-09: Simon Goldschmidt
      * dns.c: added one-shot multicast DNS queries

      2016-11-24: Ambroz Bizjak, David van Moolenbroek
      * tcp_out.c: Optimize passing contiguous nocopy buffers to tcp_write (bug #46290)

      2016-11-16: Dirk Ziegelmeier
      * sockets.c: added support for IPv6 mapped IPv4 addresses

      ++ Bugfixes:

      2016-12-16: Thomas Mueller
      * api_lib.c: fixed race condition in return value of netconn_gethostbyname()
        (and thus also lwip_gethostbyname/_r() and lwip_getaddrinfo())

      2016-12-15: David van Moolenbroek
      * opt.h, tcp: added LWIP_HOOK_TCP_ISN() to implement less predictable initial
        sequence numbers (see contrib/addons/tcp_isn for an example implementation)

      2016-12-05: Dirk Ziegelmeier
      * fixed compiling with IPv4 disabled (IPv6 only case)

      2016-11-28: Simon Goldschmidt
      * api_lib.c: fixed bug #49725 (send-timeout: netconn_write() can return
        ERR_OK without all bytes being written)

      2016-11-28: Ambroz Bizjak
      * tcpi_in.c: fixed bug #49717 (window size in received SYN and SYN-ACK
        assumed scaled)

      2016-11-25: Simon Goldschmidt
      * dhcp.c: fixed bug #49676 (Possible endless loop when parsing dhcp options)

      2016-11-23: Dirk Ziegelmeier
      * udp.c: fixed bug #49662: multicast traffic is now only received on a UDP PCB
       (and therefore on a UDP socket/netconn) when the PCB is bound to IP_ADDR_ANY

      2016-11-16: Dirk Ziegelmeier
      * *: Fixed dual-stack behaviour, IPv6 mapped IPv4 support in socket API

      2016-11-14: Joel Cunningham
      * tcp_out.c: fixed bug #49533 (start persist timer when unsent seg can't fit
        in window)

      2016-11-16: Roberto Barbieri Carrera
      * autoip.c: fixed bug #49610 (sometimes AutoIP fails to reuse the same address)

      2016-11-11: Dirk Ziegelmeier
      * sockets.c: fixed bug #49578 (dropping multicast membership does not work
        with LWIP_SOCKET_OFFSET)

    (STABLE-2.0.0)

      ++ New features:

      2016-07-27: Simon Goldschmidt
      * opt.h, timeouts.h/.c: added LWIP_TIMERS_CUSTOM to override the default
        implementation of timeouts

      2016-07-xx: Dirk Ziegelmeier
      * Large overhaul of doxygen documentation

      2016-04-05: Simon Goldschmidt
      * timers.h/.c: prepare for overriding current timeout implementation: all
        stack-internal caclic timers are avaliable in the lwip_cyclic_timers array

      2016-03-23: Simon Goldschmidt
      * tcp: call accept-callback with ERR_MEM when allocating a pcb fails on
        passive open to inform the application about this error
        ATTENTION: applications have to handle NULL pcb in accept callback!

      2016-02-22: Ivan Delamer
      * Initial 6LoWPAN support

      2016-02-XX to 2016-03-XX: Dirk Ziegelmeier
      * Cleanup TCPIP thread sync methods in a way that it is possibe to use them
        in arbitrary code that needs things to be done in TCPIP thread. Used to
        decouple netconn, netif, ppp and 6LoWPAN from LWIP core.

      2016-02-XX: Dirk Ziegelmeier
      * Implement dual-stack support in RAW, UDP and TCP. Add new IP address
        type IPADDR_ANY_TYPE for this. Netconn/Socket API: Dual-stack is
        automatically supported when an IPv6 netconn/socket is created.

      2015-12-26: Martin Hentschel and Dirk Ziegelmeier
      * Rewrite SNMP agent. SNMPv2c + MIB compiler.

      2015-11-12: Dirk Ziegelmeier
      * Decouple SNMP stack from lwIP core and move stack to apps/ directory.
        Breaking change: Users have to call snmp_init() now!

      2015-11-12: Dirk Ziegelmeier
      * Implement possibility to declare private memory pools. This is useful to
        decouple some apps from the core (SNMP stack) or make contrib app usage
        simpler (httpserver_raw)

      2015-10-09: Simon Goldschmidt
      * started to move "private" header files containing implementation details to
        "lwip/priv/" include directory to seperate the API from the implementation.

      2015-10-07: Simon Goldschmidt
      * added sntp client as first "supported" application layer protocol implementation
        added 'apps' folder

      2015-09-30: Dirk Ziegelmeier
      * snmp_structs.h, mib_structs.c, mib2.c: snmp: fixed ugly inheritance
        implementation by aggregating the "base class" (struct mib_node) in all
        derived node classes to get more type-safe code

      2015-09-23: Simon Goldschmidt
      * netif.h/.c, nd6.c: task #13729: Convert netif addresses (IPv4 & IPv6) to
        ip_addr_t (so they can be used without conversion/temporary storage)

      2015-09-08: Dirk Ziegelmeier
      * snmp: Separate mib2 counter/table callbacks from snmp agent. This both cleans
        up the code and should allow integration of a 3rd party agent/mib2. Simple
        counters are kept in MIB2_STATS, tree/table change function prototypes moved to
        snmp_mib2.h.

      2015-09-03: Simon Goldschmidt
      * opt.h, dns.h/.c: DNS/IPv6: added support for AAAA records

      2015-09-01: Simon Goldschmidt
      * task #12178: hardware checksum capabilities can be configured per netif
       (use NETIF_SET_CHECKSUM_CTRL() in your netif's init function)

      2015-08-30: Simon Goldschmidt
      * PBUF_REF with "custom" pbufs is now supported for RX pbufs (see pcapif in
        contrib for an example, LWIP_SUPPORT_CUSTOM_PBUF is required)

      2015-08-30: Simon Goldschmidt
      * support IPv4 source based routing: define LWIP_HOOK_IP4_ROUTE_SRC to point
        to a routing function

      2015-08-05: Simon Goldschmidt
      * many files: allow multicast socket options IP_MULTICAST_TTL, IP_MULTICAST_IF
        and IP_MULTICAST_LOOP to be used without IGMP

      2015-04-24: Simon Goldschmidt
      * dhcp.h/c, autoip.h/.c: added functions dhcp/autoip_supplied_address() to
        check for the source of address assignment (replacement for NETIF_FLAG_DHCP)

      2015-04-10: Simon Goldschmidt
      * many files: task #13480: added LWIP_IPV4 define - IPv4 can be disabled,
        leaving an IPv6-only stack

      2015-04-09: Simon Goldschmidt
      * nearly all files: task #12722 (improve IPv4/v6 address handling): renamed
        ip_addr_t to ip4_addr_t, renamed ipX_addr_t to ip_addr_t and added IP
        version; ip_addr_t is used for all generic IP addresses for the API,
        ip(4/6)_addr_t are only used internally or when initializing netifs or when
        calling version-related functions

      2015-03-24: Simon Goldschmidt
      * opt.h, ip4_addr.h, ip4.c, ip6.c: loopif is not required for loopback traffic
        any more but passed through any netif (ENABLE_LOOPBACK has to be enabled)

      2015-03-23: Simon Goldschmidt
      * opt.h, etharp.c: with ETHARP_TABLE_MATCH_NETIF== 1, duplicate (Auto)-IP
        addresses on multiple netifs should now be working correctly (if correctly
        addressed by routing, that is)

      2015-03-23: Simon Goldschmidt
      * etharp.c: Stable etharp entries that are about to expire are now refreshed
        using unicast to prevent unnecessary broadcast. Only if no answer is received
        after 15 seconds, broadcast is used.

      2015-03-06: Philip Gladstone
      * netif.h/.c: patch #8359 (Provide utility function to add an IPv6 address to
        an interface)

      2015-03-05: Simon Goldschmidt
      * netif.c, ip4.c, dhcp.c, autoip.c: fixed bug #37068 (netif up/down handling
        is unclear): correclty separated administrative status of a netif (up/down)
        from 'valid address' status
        ATTENTION: netif_set_up() now always has to be called, even when dhcp/autoip
        is used!

      2015-02-26: patch by TabascoEye
      * netif.c, udp.h/.c: fixed bug #40753 (re-bind UDP pcbs on change of IP address)

      2015-02-22: chrysn, Simon Goldschmidt
      * *.*: Changed nearly all functions taking 'ip(X)_addr_t' pointer to take
        const pointers (changed user callbacks: raw_recv_fn, udp_recv_fn; changed
        port callbacks: netif_output_fn, netif_igmp_mac_filter_fn)

      2015-02-19: Ivan Delamer
      * netif.h, dhcp.c: Removed unused netif flag for DHCP. The preferred way to evaluate
        if DHCP is active is through netif->dhcp field.

      2015-02-19: Ivan Delamer
      * netif.h, slipif.c, ppp.c: Removed unused netif flag for point to point connections

      2015-02-18: Simon Goldschmidt
      * api_lib.c: fixed bug #37958 "netconn API doesn't handle correctly
        connections half-closed by peer"

      2015-02-18: Simon Goldschmidt
      * tcp.c: tcp_alloc() prefers killing CLOSING/LAST_ACK over active connections
        (see bug #39565)

      2015-02-16: Claudius Zingerli, Sergio Caprile
      * opt.h, dhcp.h/.c: patch #8361 "Add support for NTP option in DHCP"

      2015-02-14: Simon Goldschmidt
      * opt.h, snmp*: added support for write-access community and dedicated
        community for sending traps

      2015-02-13: Simon Goldschmidt
      * opt.h, memp.c: added hook LWIP_HOOK_MEMP_AVAILABLE() to get informed when
        a memp pool was empty and an item is now available

      2015-02-13: Simon Goldschmidt
      * opt.h, pbuf.h/.c, etharp.c: Added the option PBUF_LINK_ENCAPSULATION_HLEN to
        allocate additional header space for TX on netifs requiring additional headers

      2015-02-12: chrysn
      * timers.h/.c: introduce sys_timeouts_sleeptime (returns the time left before
        the next timeout is due, for NO_SYS==1)

      2015-02-11: Nick van Ijzendoorn
      * opt.h, sockets.h/c: patch #7702 "Include ability to increase the socket number
        with defined offset"

      2015-02-11: Frederick Baksik
      * opt.h, def.h, others: patch #8423 "arch/perf.h" should be made an optional item

      2015-02-11: Simon Goldschmidt
      * api_msg.c, opt.h: started to implement fullduplex sockets/netconns
        (note that this is highly unstable yet!)

      2015-01-17: Simon Goldschmidt
      * api: allow enabling socket API without (public) netconn API - netconn API is
        still used by sockets, but keeping it private (static) should allow better
        compiler optimizations

      2015-01-16: Simon Goldschmidt
      * tcp_in.c: fixed bug #20506 "Initial congestion window is very small" again
        by implementing the calculation formula from RFC3390

      2014-12-10: Simon Goldschmidt
      * api: added option LWIP_NETCONN_SEM_PER_THREAD to use a semaphore per thread
        instead of using one per netconn and per select call

      2014-12-08: Simon Goldschmidt
      * ip6.h: fixed bug #43778: IPv6 header version not set on 16-bit platform
        (macro IP6H_VTCFL_SET())

      2014-12-08: Simon Goldschmidt
      * icmp.c, ip4.c, pbuf.c, udp.c, pbuf.h: task #11472 Support PBUF_REF for RX
        (IPv6 and IPv4/v6 reassembly might not work yet)

      2014-11-06: Simon Goldschmidt
      * sockets.c/.h, init.c: lwip_socket_init() is not needed any more
        -> compatibility define

      2014-09-16: Simon Goldschmidt
      * dns.c, opt.h: reduced ram usage by parsing DNS responses in place

      2014-09-16: Simon Goldschmidt
      * pbuf.h/.c: added pbuf_take_at() and pbuf_put_at()

      2014-09-15: Simon Goldschmidt
      * dns.c: added source port randomization to make the DNS client more robust
        (see bug #43144)

      2013-09-02: Simon Goldschmidt
      * arch.h and many other files: added optional macros PACK_STRUCT_FLD_8() and
        PACK_STRUCT_FLD_S() to prevent gcc 4 from warning about struct members that
        do not need packing

      2013-08-19: Simon Goldschmidt
      * netif.h: bug #42998: made NETIF_MAX_HWADDR_LEN overridable for some special
        networks

      2013-03-17: Simon Goldschmidt (patch by Ghobad Emadi)
      * opt.h, etharp.c: Added LWIP_HOOK_ETHARP_GET_GW to implement IPv4 routing with
        multiple gateways

      2013-04-20: Fatih Asici
      * opt.h, etharp.h/.c: patch #7993: Added support for transmitting packets
        with VLAN headers via hook function LWIP_HOOK_VLAN_SET and to check them
        via hook function LWIP_HOOK_VLAN_CHECK

      2014-02-20: Simon Goldschmidt (based on patch by Artem Pisarenko)
      * patch #7885: modification of api modules to support FreeRTOS-MPU
        (don't pass stack-pointers to other threads)

      2014-02-05: Simon Goldschmidt (patch by "xtian" and "alex_ab")
      * patch #6537/#7858: TCP window scaling support

      2014-01-17: Jiri Engelthaler
      * icmp, icmp6, opt.h: patch #8027: Completed HW checksuming for IPv4 and
        IPv6 ICMP's

      2012-08-22: Sylvain Rochet
      * New PPP stack for lwIP, developed in ppp-new branch.
        Based from pppd 2.4.5, released 2009-11-17, with huge changes to match
        code size and memory requirements for embedded devices, including:
        - Gluing together the previous low-level PPP code in lwIP to pppd 2.4.5, which
          is more or less what pppd sys-* files are, so that we get something working
          using the unix port.
        - Merged some patchs from lwIP Git repository which add interesting features
          or fix bugs.
        - Merged some patchs from Debian pppd package which add interesting features
          or fix bugs.
        - Ported PPP timeout handling to the lwIP timers system
        - Disabled all the PPP code using filesystem access, replaced in necessary cases
          to configuration variables.
        - Disabled all the PPP code forking processes.
        - Removed IPX support, lwIP does not support IPX.
        - Ported and improved random module from the previous PPP port.
        - Removed samba TDB (file-driven database) usage, because it needs a filesystem.
        - MS-CHAP required a DES implementation, we added the latest PolarSSL DES
          implementation which is under a BSD-ish license.
        - Also switched to PolarSSL MD4,MD5,SHA1 implementations, which are meant to be
          used in embedded devices with reduced memory footprint.
        - Removed PPP configuration file parsing support.
        - Added macro definition EAP_SUPPORT to make EAP support optional.
        - Added macro definition CHAP_SUPPORT to make CHAP support optional.
        - Added macro definition MSCHAP_SUPPORT to make MSCHAP support optional.
        - Added macro definition PAP_SUPPORT to make PAP support optional.
        - Cleared all Linux syscall calls.
        - Disabled demand support using a macro, so that it can be ported later.
        - Disabled ECP support using a macro, so that it can be ported later.
        - Disabled CCP support using a macro, so that it can be ported later.
        - Disabled CBCP support using a macro, so that it can be ported later.
        - Disabled LQR support using a macro, so that it can be ported later.
        - Print packet debug feature optional, through PRINTPKT_SUPPORT
        - Removed POSIX signal usage.
        - Fully ported PPPoS code from the previous port.
        - Fully ported PPPoE code from the previous port.
        - Fully ported VJ compression protocol code from the previous port.
        - Removed all malloc()/free() use from PPP, replaced by stack usage or PBUF.
        - Disabled PPP server support using a macro, so that it can be ported later.
        - Switched all PPP debug to lwIP debug system.
        - Created PPP Control Block (PPP PCB), removed PPP unit integer everywhere,
          removed all global variables everywhere, did everything necessary for
          the PPP stack to support more than one PPP session (pppd only support
          one session per process).
        - Removed the statically allocated output buffer, now using PBUF.
        - Improved structure size of all PPP modules, deep analyze of code to reduce
          variables size to the bare minimum. Switched all boolean type (char type in
          most architecture) to compiler generated bitfields.
        - Added PPP IPv6 support, glued lwIP IPv6 support to PPP.
        - Now using a persistent netif interface which can then be used in lwIP
          functions requiring a netif.
        - Now initializing PPP in lwip_init() function.
        - Reworked completely the PPP state machine, so that we don't end up in
          anymore in inconsistent state, especially with PPPoE.
        - Improved the way we handle PPP reconnection after disconnect, cleaning
          everything required so that we start the PPP connection again from a
          clean state.
        - Added PPP holdoff support, allow the lwIP user to wait a little bit before
          reconnecting, prevents connection flood, especially when using PPPoL2TP.
        - Added PPPoL2TP LAC support (a.k.a. UDP tunnels), adding a VPN client
          feature to lwIP, L2TP being a widely used tunnel protocol.
        - Switched all used PPP types to lwIP types (u8t, u16t, u32t, ...)
        - Added PPP API "sequential" thread-safe API, based from NETIFAPI.

      2011-07-21: Simon Goldschmidt
      * sockets.c, opt.h: (bug #30185): added LWIP_FIONREAD_LINUXMODE that makes
        ioctl/FIONREAD return the size of the next pending datagram.

      2011-05-25: Simon Goldschmidt
      * again nearly the whole stack, renamed ip.c to ip4.c, ip_addr.c to ip4_addr.c,
        combined ipv4/ipv6 inet_chksum.c, added ip.h, ip_addr.h: Combined IPv4
        and IPv6 code where possible, added defines to access IPv4/IPv6 in non-IP
        code so that the code is more readable.

      2011-05-17: Patch by Ivan Delamer (only checked in by Simon Goldschmidt)
      * nearly the whole stack: Finally, we got decent IPv6 support, big thanks to
        Ivan! (this is work in progress: we're just post release anyway :-)

      ++ Bugfixes:

      2016-08-23: Simon Goldschmidt
      * etharp: removed ETHARP_TRUST_IP_MAC since it is insecure and we don't need
        it any more after implementing unicast ARP renewal towards arp entry timeout

      2016-07-20: Simon Goldschmidt
      * memp.h/.c: fixed bug #48442 (memp stats don't work for MEMP_MEM_MALLOC)

      2016-07-21: Simon Goldschmidt (patch by Ambroz Bizjak)
      * tcp_in.c, tcp_out.c: fixed bug #48543 (TCP sent callback may prematurely
        report sent data when only part of a segment is acked) and don't include
        SYN/FIN in snd_buf counter

      2016-07-19: Simon Goldschmidt
      * etharp.c: fixed bug #48477 (ARP input packet might update static entry)

      2016-07-11: Simon Goldschmidt
      * tcp_in.c: fixed bug #48476 (TCP sent callback called wrongly due to picking
        up old pcb->acked

      2016-06-30: Simon Goldschmidt (original patch by Fabian Koch)
      * tcp_in.c: fixed bug #48170 (Vulnerable to TCP RST spoofing)

      2016-05-20: Dirk Ziegelmeier
      * sntp.h/.c: Fix return value of sntp_getserver() call to return a pointer

      2016-04-05: Simon Goldschmidt (patch by Philip Gladstone)
      * udp.c: patch #8358: allow more combinations of listening PCB for IPv6

      2016-04-05: Simon Goldschmidt
      * netconn/socket API: fixed bug# 43739 (Accept not reporting errors about
        aborted connections): netconn_accept() returns ERR_ABRT (sockets: ECONNABORTED)
        for aborted connections, ERR_CLSD (sockets: EINVAL) if the listening netconn
        is closed, which better seems to follow the standard.

      2016-03-23: Florent Matignon
      * dhcp.c: fixed bug #38203: DHCP options are not recorded in all DHCP ack messages

      2016-03-22: Simon Goldschmidt
      * tcp: changed accept handling to be done internally: the application does not
        have to call tcp_accepted() any more. Instead, when delaying accept (e.g. sockets
        do), call tcp_backlog_delayed()/tcp_backlog_accepted() (fixes bug #46696)

      2016-03-22: Simon Goldschmidt
      * dns.c: ignore dns response parsing errors, only abort resolving for correct
        responses or error responses from correct server (bug #47459)

      2016-03-17: Simon Goldschmidt
      * api_msg.c: fixed bug #47448 (netconn/socket leak if RST is received during close)

      2016-03-17: Joel Cunningham
      * api_msg.c: don't fail closing a socket/netconn when failing to allocate the
        FIN segment; blocking the calling thread for a while is better than risking
        leaking a netconn/socket (see bug #46701)

      2016-03-16: Joel Cunningham
      * tcp_out.c: reset rto timer on fast retransmission

      2016-03-16: Deomid Ryabkov
      * tcp_out.c: fixed bug #46384 Segment size calculation bug with MSS != TCP_MSS

      2016-03-05: Simon Goldschmidt
      * err.h/.c, sockets.c: ERR_IF is not necessarily a fatal error

      2015-11-19: fix by Kerem Hadimli
      * sockets.c: fixed bug #46471: lwip_accept() leaks socket descriptors if new
        netconn was already closed because of peer behavior

      2015-11-12: fix by Valery Ushakov
      * tcp_in.c: fixed bug #46365 tcp_accept_null() should call tcp_abort()

      2015-10-02: Dirk Ziegelmeier/Simon Goldschmidt
      * snmp: cleaned up snmp structs API (fixed race conditions from bug #46089,
        reduce ram/rom usage of tables): incompatible change for private MIBs

      2015-09-30: Simon Goldschmidt
      * ip4_addr.c: fixed bug #46072: ip4addr_aton() does not check the number range
        of all address parts

      2015-08-28: Simon Goldschmidt
      * tcp.c, tcp_in.c: fixed bug #44023: TCP ssthresh value is unclear: ssthresh
        is set to the full send window for active open, too, and is updated once
        after SYN to ensure the correct send window is used

      2015-08-28: Simon Goldschmidt
      * tcp: fixed bug #45559: Window scaling casts u32_t to u16_t without checks

      2015-08-26: Simon Goldschmidt
      * ip6_frag.h/.c: fixed bug bug #41009: IPv6 reassembly broken on 64-bit platforms:
        define IPV6_FRAG_COPYHEADER==1 on these platforms to copy the IPv6 header
        instead of referencing it, which gives more room for struct ip6_reass_helper

      2015-08-25: Simon Goldschmidt
      * sockets.c: fixed bug #45827: recvfrom: TCP window is updated with MSG_PEEK

      2015-08-20: Manoj Kumar
      * snmp_msg.h, msg_in.c: fixed bug #43790: Sending octet string of Length >255
        from SNMP agent

      2015-08-19: Jens Nielsen
      * icmp.c, ip4.c, tcp_in.c, udp.c, raw.c: fixed bug #45120: Broadcast & multiple
        interfaces handling

      2015-08-19: Simon Goldschmidt (patch by "Sandra")
      * dns.c: fixed bug #45004: dns response without answer might be discarded

      2015-08-18: Chrysn
      * timers.c: patch #8704 fix sys_timeouts_sleeptime function

      2015-07-01: Erik Ekman
      * puf.c: fixed bug #45454 (pbuf_take_at() skips write and returns OK if offset
        is at start of pbuf in chain)

      2015-05-19: Simon Goldschmidt
      * dhcp.h/.c: fixed bugs #45140 and #45141 (dhcp was not stopped correctly after
        fixing bug #38204)

      2015-03-21: Simon Goldschmidt (patch by Homyak)
      * tcp_in.c: fixed bug #44766 (LWIP_WND_SCALE: tcphdr->wnd was not scaled in
        two places)

      2015-03-21: Simon Goldschmidt
      * tcp_impl.h, tcp.c, tcp_in.c: fixed bug #41318 (Bad memory ref in tcp_input()
        after tcp_close())

      2015-03-21: Simon Goldschmidt
      * tcp_in.c: fixed bug #38468 (tcp_sent() not called on half-open connection for
        data ACKed with the same ack as FIN)

      2015-03-21: Simon Goldschmidt (patch by Christoffer Lind)
      * dhcp.h/.c: fixed bug #38204 (DHCP lease time not handled correctly)

      2015-03-20: Simon Goldschmidt
      * dhcp.c: fixed bug #38714 (Missing option and client address in DHCPRELEASE message)

      2015-03-19: Simon Goldschmidt
      * api.h, tcpip.h, api_lib.c, api_msg.c: fixed race conditions in assigning
        netconn->last_err (fixed bugs #38121 and #37676)

      2015-03-09: Simon Goldschmidt
      * ip4.c: fixed the IPv4 part of bug #43904 (ip_route() must detect linkup status)

      2015-03-04: Simon Goldschmidt
      * nd6.c: fixed bug #43784 (a host should send at least one Router Solicitation)

      2015-03-04: Valery Ushakov
      * ip6.c: fixed bug #41094 (Byte-order bug in IPv6 fragmentation header test)

      2015-03-04: Zach Smith
      * nd6.c: fixed bug #38153 (nd6_input() byte order issues)

      2015-02-26: Simon Goldschmidt
      * netif.c, tcp.h/.c: fixed bug #44378 (TCP connections are not aborted on netif
        remove)

      2015-02-25: Simon Goldschmidt
      * ip4.c, etharp.c: fixed bug #40177 (System hangs when dealing with corrupted
        packets), implemented task #12357 (Ensure that malicious packets don't
        assert-fail): improved some pbuf_header calls to not assert-fail.

      2015-02-25: patch by Joel Cunningham
      * udp.h/.c, sockets.c: fixed bug #43028 (IP_MULTICAST_TTL affects unicast
        datagrams)

      2015-02-25: patch by Greg Renda
      * ip4_frag.c: fixed bug #38210 (ip reassembly while remove oldest datagram)

      2015-02-25: Simon Goldschmidt
      * sockets.c: fixed bug #38165 (socket with mulicast): ensure igmp membership
        are dropped when socket (not netconn!) is closed.

      2015-02-25: Simon Goldschmidt
      * ip4.h/.c, udp.c: fixed bug #38061 (wrong multicast routing in IPv4) by
        adding an optional default netif for multicast routing

      2015-02-25: Simon Goldschmidt
      * netconn API: fixed that netconn_connect still used message passing for
        LWIP_TCPIP_CORE_LOCKING==1

      2015-02-22: patch by Jens Nielsen
      * icmp.c: fixed bug #38803 (Source address in broadcast ping reply)

      2015-02-22: Simon Goldschmidt
      * udp.h, sockets.c: added proper accessor functions for pcb->multicast_ip
        (previously used by get/setsockopt only)

      2015-02-18: Simon Goldschmidt
      * sockets.c: Fixed select not reporting received FIN as 'readable' in certain
        rare cases (bug #43779: select(), close(), and TCP retransmission error)

      2015-02-17: Simon Goldschmidt
      * err.h, sockets.c, api_msg.c: fixed bug #38853 "connect() use a wrong errno":
        return ERR_ALREADY/EALRADY during connect, ERR_ISCONN/EISCONN when already
        connected

      2015-02-17: Simon Goldschmidt
      * tcp_impl.h, tcp_out.c, tcp.c, api_msg.c: fixed bug #37614 "Errors from
        ipX_output are not processed". Now tcp_output(_segment) checks for the return
        value of ipX_output and does not try to send more on error. A netif driver
        can call tcp_txnow() (from tcpip_thread!) to try to send again if TX buffers
        are available again.

      2015-02-14: patches by Freddie Chopin
      * snmp*: made community writable, fixed some const pointers

      2015-02-13: Simon Goldschmidt
      * msg_in.c: fixed bug #22070 "MIB_OBJECT_WRITE_ONLY not implemented in SNMP"

      2015-02-12: Simon Goldschmidt
      * ip.h, ip4.c, ip6.c: fixed bug #36403 "ip4_input() and ip6_input() always pass
        inp to higher layers": now the accepting netif is passed up, but the input
        netif is available through ip_current_input_netif() if required.

      2015-02-11: patch by hichard
      * tcpip.c: fixed bug #43094 "The function tcpip_input() forget to handle IPv6"

      2015-02-10: Simon Goldschmidt
      * netconn API: fixed that netconn_close/netconn_delete still used message passing
        for LWIP_TCPIP_CORE_LOCKING==1

      2015-02-10: Simon Goldschmidt
      * netconn/socket api: fixed bug #44225 "closing TCP socket should time out
        eventually", implemented task #6930 "Implement SO_LINGER": closing TCP sockets
        times out after 20 seconds or after the configured SND_TIMEOUT or depending
        on the linger settings.

      2015-01-27: Simon Goldschmidt
      * api_msg.c: fixed that SHUT_RD followed by SHUT_WR was different to SHUT_RDWR,
        fixed return value of lwip_netconn_do_close on unconnected netconns

      2015-01-17: Simon Goldschmidt
      * sockets.c: fixed bug #43361 select() crashes with stale FDs

      2015-01-17: Simon Goldschmidt
      * sockets.c/.h, memp_std.h: fixed bug #40788 "lwip_setsockopt_internal() crashes"
        by rewriting set/getsockopt functions to combine checks with the actual code
        and add more NULL checks; this also fixes that CORE_LOCKING used message
        passing for set/getsockopt.

      2014-12-19: Simon Goldschmidt
      * opt.h, dhcp.h/.c: prevent dhcp from starting when netif link is down (only
        when LWIP_DHCP_CHECK_LINK_UP==1, which is disabled by default for
        compatibility reasons)

      2014-12-17: Simon Goldschmidt
      * tcp_out.c: fixed bug #43840 Checksum error for TCP_CHECKSUM_ON_COPY==1 for
        no-copy data with odd length

      2014-12-10: Simon Goldschmidt
      * sockets.c, tcp.c, others: fixed bug #43797 set/getsockopt: SO_SNDTIMEO/SO_RCVTIMEO
        take int as option but should take timeval (LWIP_SO_SNDRCVTIMEO_STANDARD==0 can
        be used to revert to the old 'winsock' style behaviour)
        Fixed implementation of SO_ACCEPTCONN to just look at the pcb state

      2014-12-09: Simon Goldschmidt
      * ip4.c: fixed bug #43596 IGMP queries from 0.0.0.0 are discarded

      2014-10-21: Simon Goldschmidt (patch by Joel Cunningham and Albert Huitsing)
      * sockts.c: fixed bugs #41495 Possible threading issue in select() and #43278
        event_callback() handle context switch when calling sys_sem_signal()

      2014-10-21: Simon Goldschmidt
      * api_msg.c: fixed bug #38219 Assert on TCP netconn_write with sndtimeout set

      2014-09-16: Kevin Cernekee
      * dns.c: patch #8480 Fix handling of dns_seqno wraparound

      2014-09-16: Simon Goldschmidt
      * tcp_out.c: fixed bug #43192 tcp_enqueue_flags() should not check TCP_SND_QUEUELEN
        when sending FIN

      2014-09-03: Simon Goldschmidt
      * msg_in.c: fixed bug #39355 SNMP Memory Leak in case of error

      2014-09-02: Simon Goldschmidt
      * err.h/.c, sockets.c, api_msg.c: fixed bug #43110 call getpeername() before
        listen() will cause a error

      2014-09-02: Simon Goldschmidt
      * sockets.c: fixed bug #42117 lwip_fcntl does not set errno

      2014-09-02: Simon Goldschmidt
      * tcp.c: fixed bug #42299 tcp_abort() leaves freed pcb on tcp_bound_pcbs list

      2014-08-20: Simon Goldschmidt
      * dns.c: fixed bug #42987 lwIP is vulnerable to DNS cache poisoning due to
        non-randomized TXIDs

      2014-06-03: Simon Goldschmidt
      * tcp_impl.h, tcp_in.c: fixed bug #37969 SYN packet dropped as short packet in
        tcp_input function

      2014-05-20: Simon Goldschmidt
      * tcp_out.c: fixed bug #37184 tcp_write problem for pcbs in the SYN_SENT state

      2014-05-19: Simon Goldschmidt
      * *.h: Fixed bug #35874 reserved identifier violation (removed leading underscores
        from header include guards)

      2014-04-08: Simon Goldschmidt
      * tcp.c: Fixed bug #36167 tcp server crash when client closes (maximum window)

      2014-04-06: Simon Goldschmidt
      * tcp_in.c: Fixed bug #36210 lwIP does not elicit an empty ACK when received
        unacceptable ACK

      2014-04-06: Simon Goldschmidt
      * dhcp.c, ip4.c/.h, ip6.c/.h, udp.c/.h, ip.h: Fixed bug #41787 DHCP Discovery
        is invalid when an IP is set to thet netif.

      2014-03-14: Simon Goldschmidt
      * tcp_out.c: Fixed bug #36153 TCP Cheksum error if LWIP_CHECKSUM_ON_COPY=1

      2014-03-11: Simon Goldschmidt (patch by Mason)
      * opt.h, sockets.c: fixed bug #35928 BSD sockets functions must set errno for
        POSIX-compliance

      2014-02-27: Simon Goldschmidt
      * dhcp.c: fixed bug #40303 DHCP xid renewed when sending a DHCPREQUEST

      2014-02-27: Simon Goldschmidt
      * raw.c: fixed bug #41680 raw socket can not receive IPv6 packet when
        IP_SOF_BROADCAST_RECV==1

      2014-02-27: Simon Goldschmidt
      * api_msg.c, sockets.c: fixed bug #38404 getpeeraddr returns success on
        unconnected/listening TCP sockets

      2014-02-27: Simon Goldschmidt
      * sockets.c: fixed bug #41729 Some socket functions return Exyz instead of -1

      2014-02-25: Simon Goldschmidt
      * ip4.c: fixed bug #39514 ip_route() may return an IPv6-only interface

      2014-02-25: Simon Goldschmidt, patch by Fatih Asici
      * pbuf.c: fixed bug #39356 Wrong increment in pbuf_memfind()

      2014-02-25: Simon Goldschmidt
      * netif.c/.h, udp.c: fixed bug #39225 udp.c uses netif_matches_ip6_addr() incorrectly;
        renamed function netif_matches_ip6_addr() to netif_get_ip6_addr_match()

      2014-02-25: Simon Goldschmidt
      * igmp.c: fixed bug #39145 IGMP membership report for 224.0.0.1

      2014-02-22: Simon Goldschmidt (patch by Amir Shalem)
      * etharp.c, opt.h: fixed bug #34681 Limit ARP queue length by ARP_QUEUE_LEN (=3)

      2014-02-22: Simon Goldschmidt (patch by Amir Shalem)
      * etharp.h/.c: fixed bug #34682 Limit ARP request flood for unresolved entry

      2014-02-20: Simon Goldschmidt
      * tcp_out.c: fixed bug #39683 Assertion "seg->tcphdr not aligned" failed with
        MEM_ALIGNMENT = 8

      2014-02-20: Simon Goldschmidt
      * sockets.c: fixed bug #39882 No function shall set errno to 0

      2014-02-20: Simon Goldschmidt
      * mib_structs.c: fixed bug #40050 SNMP problem with MIB arrays > 255

      2014-02-20: Simon Goldschmidt
      * api.h, sockets.c: fixed bug #41499 netconn::recv_avail can overflow

      2014-01-08: Stathis Voukelatos
      * memp_std.h: patch #7928 Fixed size calculation in MALLOC memory pool
        creation macro

      2014-01-18: Brian Fahs
      * tcp_out.c: patch #8237: tcp_rexmit_rto fails to update pcb->unsent_oversize
        when necessary

      2014-01-17: Grant Erickson, Jay Logue, Simon Goldschmidt
      * ipv6.c, netif.c: patch #7913 Enable Support for IPv6 Loopback

      2014-01-16: Stathis Voukelatos
      * netif.c: patch #7902 Fixed netif_poll() operation when LWIP_LOOPBACK_MAX_PBUFS > 0

      2014-01-14: "Freddie Chopin"
      * snmp.h, mib2.c: fixed constness and spelling of sysdescr

      2014-01-14: Simon Goldschmidt (patch by Thomas Faber)
      * tcpip.c: patch #8241: Fix implicit declaration of ip_input with
        LWIP_TCPIP_CORE_LOCKING_INPUT disabled

      2014-01-14: chrysn
      * timers.c: patch #8244 make timeouts usable reliably from outside of the
        timeout routine

      2014-01-10: Simon Goldschmidt
      * ip_frag.c, ip6_frag.c: fixed bug #41041 Potential use-after-free in IPv6 reassembly

      2014-01-10: Simon Goldschmidt
      * memp.c: fixed bug #41188 Alignment error in memp_init() when MEMP_SEPARATE_POOLS==1

      2014-01-10: Simon Goldschmidt
      * tcp.c: fixed bug #39898 tcp_fasttmr() possible lock due to infinte queue process loop

      2013-06-29: Simon Goldschmidt
      * inet.h, sockets.h: partially fixed bug #37585: IPv6 compatibility (in socket structs)

      2013-06-29: Simon Goldschmidt
      * inet6.h: bug #37585/task #12600: fixed struct in6_addr.s6_addr to conform to spec

      2013-04-24: patch by Liam <morepork>
      * api_msg.c: patch #8008 Fix a potential null pointer dereference in assert

      2013-04-24: Simon Goldschmidt
      * igmp.c: fixed possible division by zero

      2013-04-24: Simon Goldschmidt
      * ip6.h, some ipv6 C files: fixed bug #38526 Coverity: Recursive Header Inclusion in ip6.h

      2013-04-24: Simon Goldschmidt (patch by Emil Ljungdahl):
      * netif.c: fixed bug #38586 netif_loop_output() "deadlocks"

      2013-01-15: Simon Goldschmidt
      * ip4.c: fixed bug #37665 ip_canforward operates on address in wrong byte order

      2013-01-15: Simon Goldschmidt
      * pbuf.h: fixed bug #38097 pbuf_free_ooseq() warning

      2013-01-14: Simon Goldschmidt
      * dns.c: fixed bug #37705 Possible memory corruption in DNS query

      2013-01-11: Simon Goldschmidt
      * raw.c: fixed bug #38066 Raw pcbs can alter packet without eating it

      2012-08-22: Simon Goldschmidt
      * memp.c: fixed bug #37166: memp_sanity check loops itself

      2012-08-13: Simon Goldschmidt
      * dhcp.c: fixed bug #36645: Calling dhcp_release before dhcp_start
        dereferences NULL

      2012-08-13: Simon Goldschmidt
      * msg_out.c: fixed bug #36840 snmp_send_trap() NULL de-reference if traps
        configured but no interfaces available

      2012-08-13: Simon Goldschmidt
      * dns.c: fixed bug #36899 DNS TTL 0 is cached for a long time

      2012-05-11: Simon Goldschmidt (patch by Marty)
      * memp.c: fixed bug #36412: memp.c does not compile when
        MEMP_OVERFLOW_CHECK > zero and MEMP_SEPARATE_POOLS == 1

      2012-05-03: Simon Goldschmidt (patch by Sylvain Rochet)
      * ppp.c: fixed bug #36283 (PPP struct used on header size computation and
        not packed)

      2012-05-03: Simon Goldschmidt (patch by David Empson)
      * ppp.c: fixed bug #36388 (PPP: checksum-only in last pbuf leads to pbuf with
        zero length)

      2012-03-25: Simon Goldschmidt
      * api_msg.c: Fixed bug #35817: do_connect() invalidly signals op_completed
        for UDP/RAW with LWIP_TCPIP_CORE_LOCKING==1

      2012-03-25: Simon Goldschmidt
      * api_msg.h, api_lib.c, api_msg.c, netifapi.c: fixed bug #35931: Name space
        pollution in api_msg.c and netifapi.c

      2011-08-24: Simon Goldschmidt
      * inet6.h: fixed bug #34124 struct in6_addr does not conform to the standard

    (STABLE-1.4.1)

      ++ New features:

      2012-03-25: Simon Goldschmidt (idea by Mason)
      * posix/*: added posix-compatibility include files posix/netdb.h and posix/sys/socket.h
        which are a simple wrapper to the correct lwIP include files.

      2012-01-16: Simon Goldschmidt
      * opt.h, icmp.c: Added option CHECKSUM_GEN_ICMP

      2011-12-17: Simon Goldschmidt
      * ip.h: implemented API functions to access so_options of IP pcbs (UDP, TCP, RAW)
        (fixes bug #35061)

      2011-09-27: Simon Goldschmidt
      * opt.h, tcp.c, tcp_in.c: Implemented limiting data on ooseq queue (task #9989)
        (define TCP_OOSEQ_MAX_BYTES / TCP_OOSEQ_MAX_PBUFS in lwipopts.h)

      2011-09-21: Simon Goldschmidt
      * opt.h, api.h, api_lib.c, api_msg.h/.c, sockets.c: Implemented timeout on
        send (TCP only, bug #33820)

      2011-09-21: Simon Goldschmidt
      * init.c: Converted runtime-sanity-checks into compile-time checks that can
        be disabled (since runtime checks can often not be seen on embedded targets)

      2011-09-11: Simon Goldschmidt
      * ppp.h, ppp_impl.h: splitted ppp.h to an internal and external header file
        to get a clear separation of which functions an application or port may use
        (task #11281)

     2011-09-11: Simon Goldschmidt
      * opt.h, tcp_impl.h, tcp.c, udp.h/.c: Added a config option to randomize
        initial local TCP/UDP ports (so that different port ranges are used after
        a reboot; bug #33818; this one added tcp_init/udp_init functions again)

      2011-09-03: Simon Goldschmidt
      * dhcp.c: DHCP uses LWIP_RAND() for xid's (bug #30302)

      2011-08-24: Simon Goldschmidt
      * opt.h, netif.h/.c: added netif remove callback (bug #32397)

      2011-07-26: Simon Goldschmidt
      * etharp.c: ETHARP_SUPPORT_VLAN: add support for an external VLAN filter
        function instead of only checking for one VLAN (define ETHARP_VLAN_CHECK_FN)

      2011-07-21: Simon Goldschmidt (patch by hanhui)
      * ip4.c, etharp.c, pbuf.h: bug #33634 ip_forward() have a faulty behaviour:
        Added pbuf flags to mark incoming packets as link-layer broadcast/multicast.
        Also added code to allow ip_forward() to forward non-broadcast packets to
        the input netif (set IP_FORWARD_ALLOW_TX_ON_RX_NETIF==1).

      2011-06-26: Simon Goldschmidt (patch by Cameron Gutman)
      * tcp.c, tcp_out.c: bug #33604: added some more asserts to check that
        pcb->state != LISTEN

       2011-05-14: Simon Goldschmidt (patch by Stéphane Lesage)
      * tcpip.c/.h: patch #7449 allow tcpip callback from interrupt with static
        memory message

      ++ Bugfixes:

      2012-09-26: Simon Goldschmidt
      * api_msg.c: fixed bug #37405 'err_tcp()' uses already freed 'netconn' object

      2012-09-26: patch by Henrik Persson
      * dhcp.c: patch #7843 Fix corner case with dhcp timeouts

      2012-09-26: patch by Henrik Persson
      * dhcp.c: patch #7840 Segfault in dhcp_parse_reply if no end marker in dhcp packet

      2012-08-22: Simon Goldschmidt
      * memp.c: fixed bug #37166: memp_sanity check loops itself

      2012-05-08: Simon Goldschmidt
      * tcp_out.c: fixed bug: #36380 unsent_oversize mismatch in 1.4.1RC1 (this was
        a debug-check issue only)

      2012-03-27: Simon Goldschmidt
      * vj.c: fixed bug #35756 header length calculation problem in ppp/vj.c

      2012-03-27: Simon Goldschmidt (patch by Mason)
      * tcp_out.c: fixed bug #35945: SYN packet should provide the recv MSS not the
        send MSS

      2012-03-22: Simon Goldschmidt
      * ip4.c: fixed bug #35927: missing refragmentaion in ip_forward

      2012-03-20: Simon Goldschmidt (patch by Mason)
      * netdb.c: fixed bug #35907: lwip_gethostbyname_r returns an invalid h_addr_list

      2012-03-12: Simon Goldschmidt (patch by Bostjan Meglic)
      * ppp.c: fixed bug #35809: PPP GetMask(): Compiler warning on big endian,
        possible bug on little endian system

      2012-02-23: Simon Goldschmidt
      * etharp.c: fixed bug #35595: Impossible to send broadcast without a gateway
        (introduced when fixing bug# 33551)

      2012-02-16: Simon Goldschmidt
      * ppp.c: fixed pbuf leak when PPP session is aborted through pppSigHUP()
        (bug #35541: PPP Memory Leak)

      2012-02-16: Simon Goldschmidt
      * etharp.c: fixed bug #35531: Impossible to send multicast without a gateway
        (introduced when fixing bug# 33551)

      2012-02-16: Simon Goldschmidt (patch by Stéphane Lesage)
      * msg_in.c, msg_out.c: fixed bug #35536 SNMP: error too big response is malformed

      2012-02-15: Simon Goldschmidt
      * init.c: fixed bug #35537: MEMP_NUM_* sanity checks should be disabled with
        MEMP_MEM_MALLOC==1

      2012-02-12: Simon Goldschmidt
      * tcp.h, tcp_in.c, tcp_out.c: partly fixed bug #25882: TCP hangs on
        MSS > pcb->snd_wnd (by not creating segments bigger than half the window)

      2012-02-11: Simon Goldschmidt
      * tcp.c: fixed bug #35435: No pcb state check before adding it to time-wait
        queue while closing

      2012-01-22: Simon Goldschmidt
      * tcp.c, tcp_in.c: fixed bug #35305: pcb may be freed too early on shutdown(WR)

      2012-01-21: Simon Goldschmidt
      * tcp.c: fixed bug #34636: FIN_WAIT_2 - Incorrect shutdown of TCP pcb

      2012-01-20: Simon Goldschmidt
      * dhcp.c: fixed bug #35151: DHCP asserts on incoming option lengths

     2012-01-20: Simon Goldschmidt
      * pbuf.c: fixed bug #35291: NULL pointer in pbuf_copy

      2011-11-25: Simon Goldschmidt
      * tcp.h/.c, tcp_impl.h, tcp_in.c: fixed bug #31177: tcp timers can corrupt
        tcp_active_pcbs in some cases

      2011-11-23: Simon Goldschmidt
      * sys.c: fixed bug #34884: sys_msleep() body needs to be surrounded with
        '#ifndef sys_msleep'

      2011-11-22: Simon Goldschmidt
      * netif.c, etharp.h/.c: fixed bug #34684: Clear the arp table cache when
        netif is brought down

      2011-10-28: Simon Goldschmidt
      * tcp_in.c: fixed bug #34638: Dead code in tcp_receive - pcb->dupacks

      2011-10-23: Simon Goldschmidt
      * mem.c: fixed bug #34429: possible memory corruption with
        LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT set to 1

      2011-10-18: Simon Goldschmidt
      * arch.h, netdb.c: fixed bug #34592: lwip_gethostbyname_r uses nonstandard
        error value

      2011-10-18: Simon Goldschmidt
      * opt.h: fixed default values of TCP_SNDLOWAT and TCP_SNDQUEUELOWAT for small
        windows (bug #34176 select after non-blocking send times out)

      2011-10-18: Simon Goldschmidt
      * tcp_impl.h, tcp_out.c: fixed bug #34587: TCP_BUILD_MSS_OPTION doesn't
        consider netif->mtu, causes slow network

      2011-10-18: Simon Goldschmidt
      * sockets.c: fixed bug #34581 missing parentheses in udplite sockets code

      2011-10-18: Simon Goldschmidt
      * sockets.h: fixed bug #34580 fcntl() is missing in LWIP_COMPAT_SOCKETS

      2011-10-17: Simon Goldschmidt
      * api_msg.c: fixed bug #34569: shutdown(SHUT_WR) crashes netconn/socket api

      2011-10-13: Simon Goldschmidt
      * tcp_in.c, tcp_out.c: fixed bug #34517 (persist timer is started although no
        zero window is received) by starting the persist timer when a zero window is
        received, not when we have more data queued for sending than fits into the
        window

      2011-10-13: Simon Goldschmidt
      * def.h, timers.c: fixed bug #34541: LWIP_U32_DIFF is unnecessarily complex

      2011-10-13: Simon Goldschmidt
      * sockets.c, api_lib.c: fixed bug #34540: compiler error when CORE_LOCKING is
        used and not all protocols are enabled

      2011-10-12: Simon Goldschmidt
      * pbuf.c: fixed bug #34534: Error in sending fragmented IP if MEM_ALIGNMENT > 4

      2011-10-09: Simon Goldschmidt
      * tcp_out.c: fixed bug #34426: tcp_zero_window_probe() transmits incorrect
        byte value when pcb->unacked != NULL

      2011-10-09: Simon Goldschmidt
      * ip4.c: fixed bug #34447 LWIP_IP_ACCEPT_UDP_PORT(dst_port) wrong

      2011-09-27: Simon Goldschmidt
      * tcp_in.c, tcp_out.c: Reset pcb->unsent_oversize in 2 more places...

      2011-09-27: Simon Goldschmidt
      * tcp_in.c: fixed bug #28288: Data after FIN in oos queue

      2011-09-27: Simon Goldschmidt
      * dhcp.c: fixed bug #34406 dhcp_option_hostname() can overflow the pbuf

      2011-09-24: Simon Goldschmidt
      * mem.h: fixed bug #34377 MEM_SIZE_F is not defined if MEM_LIBC_MALLOC==1

      2011-09-23: Simon Goldschmidt
      * pbuf.h, tcp.c, tcp_in.c: fixed bug #33871: rejecting TCP_EVENT_RECV() for
        the last packet including FIN can lose data

      2011-09-22: Simon Goldschmidt
      * tcp_impl.h: fixed bug #34355: nagle does not take snd_buf/snd_queuelen into
        account

      2011-09-21: Simon Goldschmidt
      * opt.h: fixed default value of TCP_SND_BUF to not violate the sanity checks
        in init.c

      2011-09-20: Simon Goldschmidt
      * timers.c: fixed bug #34337 (possible NULL pointer in sys_check_timeouts)

      2011-09-11: Simon Goldschmidt
      * tcp_out.c: use pcb->mss instead of TCP_MSS for preallocate mss-sized pbufs
        (bug #34019)

      2011-09-09: Simon Goldschmidt
      * udp.c: fixed bug #34072: UDP broadcast is received from wrong UDP pcb if
        udp port matches

      2011-09-03: Simon Goldschmidt
      * tcp_in.c: fixed bug #33952 PUSH flag in incoming packet is lost when packet
        is aggregated and sent to application

      2011-09-01: Simon Goldschmidt
      * opt.h: fixed bug #31809 LWIP_EVENT_API in opts.h is inconsistent compared
        to other options

      2011-09-01: Simon Goldschmidt
      * tcp_in.c: fixed bug #34111 RST for ACK to listening pcb has wrong seqno

      2011-08-24: Simon Goldschmidt
      * api_msg.c, sockets.c: fixed bug #33956 Wrong error returned when calling
        accept() on UDP connections

      2011-08-24: Simon Goldschmidt
      * sockets.h: fixed bug #34057 socklen_t should be a typedef

      2011-08-24: Simon Goldschmidt
      * pbuf.c: fixed bug #34112 Odd check in pbuf_alloced_custom (typo)

      2011-08-24: Simon Goldschmidt
      * dhcp.c: fixed bug #34122 dhcp: hostname can overflow

      2011-08-24: Simon Goldschmidt
      * netif.c: fixed bug #34121 netif_add/netif_set_ipaddr fail on NULL ipaddr

      2011-08-22: Simon Goldschmidt
      * tcp_out.c: fixed bug #33962 TF_FIN not always set after FIN is sent. (This
        merely prevents nagle from not transmitting fast after closing.)

      2011-07-22: Simon Goldschmidt
      * api_lib.c, api_msg.c, sockets.c, api.h: fixed bug #31084 (socket API returns
        always EMSGSIZE on non-blocking sockets if data size > send buffers) -> now
        lwip_send() sends as much as possible for non-blocking sockets

      2011-07-22: Simon Goldschmidt
      * pbuf.c/.h, timers.c: freeing ooseq pbufs when the pbuf pool is empty implemented
        for NO_SYS==1: when not using sys_check_timeouts(), call PBUF_CHECK_FREE_OOSEQ()
        at regular intervals from main level.

      2011-07-21: Simon Goldschmidt
      * etharp.c: fixed bug #33551 (ARP entries may time out although in use) by
        sending an ARP request when an ARP entry is used in the last minute before
        it would time out.

      2011-07-04: Simon Goldschmidt
      * sys_arch.txt: Fixed documentation after changing sys arch prototypes for 1.4.0.

      2011-06-26: Simon Goldschmidt
      * tcp.c: fixed bug #31723 (tcp_kill_prio() kills pcbs with the same prio) by
        updating its documentation only.

     2011-06-26: Simon Goldschmidt
      * mem.c: fixed bug #33545: With MEM_USE_POOLS==1, mem_malloc can return an
        unaligned pointer.

      2011-06-26: Simon Goldschmidt
      * mem.c: fixed bug #33544 "warning in mem.c in lwip 1.4.0 with NO_SYS=1"

       2011-05-25: Simon Goldschmidt
      * tcp.c: fixed bug #33398 (pointless conversion when checking TCP port range)

    (STABLE-1.4.0)

      ++ New features:

      2011-03-27: Simon Goldschmidt
      * tcp_impl.h, tcp_in.c, tcp_out.c: Removed 'dataptr' from 'struct tcp_seg' and
        calculate it in tcp_zero_window_probe (the only place where it was used).

      2010-11-21: Simon Goldschmidt
      * dhcp.c/.h: Added a function to deallocate the struct dhcp from a netif
        (fixes bug #31525).

      2010-07-12: Simon Goldschmidt (patch by Stephane Lesage)
      * ip.c, udp.c/.h, pbuf.h, sockets.c: task #10495: Added support for
        IP_MULTICAST_LOOP at socket- and raw-API level.

      2010-06-16: Simon Goldschmidt
      * ip.c: Added an optional define (LWIP_IP_ACCEPT_UDP_PORT) that can allow
        link-layer-addressed UDP traffic to be received while a netif is down (just
        like DHCP during configuration)

      2010-05-22: Simon Goldschmidt
      * many many files: bug #27352: removed packing from ip_addr_t, the packed
        version is now only used in protocol headers. Added global storage for
        current src/dest IP address while in input functions.

      2010-05-16: Simon Goldschmidt
      * def.h: task #10391: Add preprocessor-macros for compile-time htonl
        calculation (and use them throughout the stack where applicable)

      2010-05-16: Simon Goldschmidt
      * opt.h, memp_std.h, memp.c, ppp_oe.h/.c: PPPoE now uses its own MEMP pool
        instead of the heap (moved struct pppoe_softc from ppp_oe.c to ppp_oe.h)

      2010-05-16: Simon Goldschmidt
      * opt.h, memp_std.h, dns.h/.c: DNS_LOCAL_HOSTLIST_IS_DYNAMIC uses its own
        MEMP pool instead of the heap

      2010-05-13: Simon Goldschmidt
      * tcp.c, udp.c: task #6995: Implement SO_REUSEADDR (correctly), added
        new option SO_REUSE_RXTOALL to pass received UDP broadcast/multicast
        packets to more than one pcb.

      2010-05-02: Simon Goldschmidt
      * netbuf.h/.c, sockets.c, api_msg.c: use checksum-on-copy for sending
        UDP data for LWIP_NETIF_TX_SINGLE_PBUF==1

      2010-04-30: Simon Goldschmidt
      * udp.h/.c, pbuf.h/.c: task #6849: added udp_send(_to/_if) functions that
        take a precalculated checksum, added pbuf_fill_chksum() to copy data
        into a pbuf and at the same time calculating the checksum for that data

      2010-04-29: Simon Goldschmidt
      * ip_addr.h, etharp.h/.c, autoip.c: Create overridable macros for copying
        2-byte-aligned IP addresses and MAC addresses

      2010-04-28: Patch by Bill Auerbach
      * ip.c: Inline generating IP checksum to save a function call

      2010-04-14: Simon Goldschmidt
      * tcpip.h/.c, timers.c: Added an overridable define to get informed when the
        tcpip_thread processes messages or timeouts to implement a watchdog.

      2010-03-28: Simon Goldschmidt
      * ip_frag.c: create a new (contiguous) PBUF_RAM for every outgoing
        fragment if LWIP_NETIF_TX_SINGLE_PBUF==1

      2010-03-27: Simon Goldschmidt
      * etharp.c: Speedup TX by moving code from find_entry to etharp_output/
        etharp_query to prevent unnecessary function calls (inspired by
        patch #7135).

      2010-03-20: Simon Goldschmidt
      * opt.h, tcpip.c/.h: Added an option to disable tcpip_(un)timeout code
        since the linker cannot do this automatically to save space.

      2010-03-20: Simon Goldschmidt
      * opt.h, etharp.c/.h: Added support for static ARP table entries

      2010-03-14: Simon Goldschmidt
      * tcp_impl.h, tcp_out.c, inet_chksum.h/.c: task #6849: Calculate checksum
        when creating TCP segments, not when (re-)transmitting them.

      2010-03-07: Simon Goldschmidt
      * sockets.c: bug #28775 (select/event_callback: only check select_cb_list
        on change) plus use SYS_LIGHTWEIGHT_PROT to protect the select code.
        This should speed up receiving data on sockets as the select code in
        event_callback is only executed when select is waiting.

      2010-03-06: Simon Goldschmidt
      * tcp_out.c: task #7013 (Create option to have all packets delivered to
        netif->output in one piece): Always copy to try to create single pbufs
        in tcp_write.

      2010-03-06: Simon Goldschmidt
      * api.h, api_lib.c, sockets.c: task #10167 (sockets: speed up TCP recv
        by not allocating a netbuf): added function netconn_recv_tcp_pbuf()
        for tcp netconns to receive pbufs, not netbufs; use that function
        for tcp sockets.

      2010-03-05: Jakob Ole Stoklundsen / Simon Goldschmidt
      * opt.h, tcp.h, tcp_impl.h, tcp.c, tcp_in.c, tcp_out.c: task #7040:
        Work on tcp_enqueue: Don't waste memory when chaining segments,
        added option TCP_OVERSIZE to prevent creating many small pbufs when
        calling tcp_write with many small blocks of data. Instead, pbufs are
        allocated larger than needed and the space is used for later calls to
        tcp_write.

      2010-02-21: Simon Goldschmidt
      * stats.c/.h: Added const char* name to mem- and memp-stats for easier
        debugging.

      2010-02-21: Simon Goldschmidt
      * tcp.h (and usages), added tcp_impl.h: Splitted API and internal
        implementation of tcp to make API usage cleare to application programmers

      2010-02-14: Simon Goldschmidt/Stephane Lesage
      * ip_addr.h: Improved some defines working on ip addresses, added faster
        macro to copy addresses that cannot be NULL

      2010-02-13: Simon Goldschmidt
      * api.h, api_lib.c, api_msg.c, sockets.c: task #7865 (implement non-
        blocking send operation)

      2010-02-12: Simon Goldschmidt
      * sockets.c/.h: Added a minimal version of posix fctl() to have a
        standardised way to set O_NONBLOCK for nonblocking sockets.

      2010-02-12: Simon Goldschmidt
      * dhcp.c/.h, autoip.c/.h: task #10139 (Prefer statically allocated
        memory): added autoip_set_struct() and dhcp_set_struct() to let autoip
        and dhcp work with user-allocated structs instead of callin mem_malloc

      2010-02-12: Simon Goldschmidt/Jeff Barber
      * tcp.c/h: patch #6865 (SO_REUSEADDR for TCP): if pcb.so_options has
        SOF_REUSEADDR set, allow binding to endpoint in TIME_WAIT

      2010-02-12: Simon Goldschmidt
      * sys layer: task #10139 (Prefer statically allocated memory): converted
        mbox and semaphore functions to take pointers to sys_mbox_t/sys_sem_t;
        converted sys_mbox_new/sys_sem_new to take pointers and return err_t;
        task #7212: Add Mutex concept in sys_arch (define LWIP_COMPAT_MUTEX
        to let sys.h use binary semaphores instead of mutexes - as before)

      2010-02-09: Simon Goldschmidt (Simon Kallweit)
      * timers.c/.h: Added function sys_restart_timeouts() from patch #7085
        (Restart system timeout handling)

      2010-02-09: Simon Goldschmidt
      * netif.c/.h, removed loopif.c/.h: task #10153 (Integrate loopif into
        netif.c) - loopif does not have to be created by the port any more,
        just define LWIP_HAVE_LOOPIF to 1.

      2010-02-08: Simon Goldschmidt
      * inet.h, ip_addr.c/.h: Added reentrant versions of inet_ntoa/ipaddr_ntoa
        inet_ntoa_r/ipaddr_ntoa_r

      2010-02-08: Simon Goldschmidt
      * netif.h: Added netif_s/get_igmp_mac_filter() macros

      2010-02-05: Simon Goldschmidt
      * netif.h: Added function-like macros to get/set the hostname on a netif

      2010-02-04: Simon Goldschmidt
      * nearly every file: Replaced struct ip_addr by typedef ip_addr_t to
        make changing the actual implementation behind the typedef easier.

      2010-02-01: Simon Goldschmidt
      * opt.h, memp_std.h, dns.h, netdb.c, memp.c: Let netdb use a memp pool
        for allocating memory when getaddrinfo() is called.

      2010-01-31: Simon Goldschmidt
      * dhcp.h, dhcp.c: Reworked the code that parses DHCP options: parse
        them once instead of parsing for every option. This also removes
        the need for mem_malloc from dhcp_recv and makes it possible to
        correctly retrieve the BOOTP file.

      2010-01-30: simon Goldschmidt
      * sockets.c: Use SYS_LIGHTWEIGHT_PROT instead of a semaphore to protect
        the sockets array.

      2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
      * api.h, api_msg.c, sockets.c: Added except set support in select
        (patch #6860)

      2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
      * api.h, sockets.h, err.h, api_lib.c, api_msg.c, sockets.c, err.c:
        Add non-blocking support for connect (partly from patch #6860),
        plus many cleanups in socket & netconn API.

      2010-01-27: Simon Goldschmidt
      * opt.h, tcp.h, init.c, api_msg.c: Added TCP_SNDQUEUELOWAT corresponding
        to TCP_SNDLOWAT and added tcp_sndqueuelen() - this fixes bug #28605

      2010-01-26: Simon Goldschmidt
      * snmp: Use memp pools for snmp instead of the heap; added 4 new pools.

      2010-01-14: Simon Goldschmidt
      * ppp.c/.h: Fixed bug #27856: PPP: Set netif link- and status-callback
        by adding ppp_set_netif_statuscallback()/ppp_set_netif_linkcallback()

      2010-01-13: Simon Goldschmidt
      * mem.c: The heap now may be moved to user-defined memory by defining
        LWIP_RAM_HEAP_POINTER as a void pointer to that memory's address
        (patch #6966 and bug #26133)

      2010-01-10: Simon Goldschmidt (Bill Auerbach)
      * opt.h, memp.c: patch #6822 (Add option to place memory pools in
        separate arrays)

      2010-01-10: Simon Goldschmidt
      * init.c, igmp.c: patch #6463 (IGMP - Adding Random Delay): added define
        LWIP_RAND() for lwip-wide randomization (to be defined in cc.h)

      2009-12-31: Simon Goldschmidt
      * tcpip.c, init.c, memp.c, sys.c, memp_std.h, sys.h, tcpip.h
        added timers.c/.h: Separated timer implementation from semaphore/mbox
        implementation, moved timer implementation to timers.c/.h, timers are
        now only called from tcpip_thread or by explicitly checking them.
        (TASK#7235)

      2009-12-27: Simon Goldschmidt
      * opt.h, etharp.h/.c, init.c, tcpip.c: Added an additional option
        LWIP_ETHERNET to support ethernet without ARP (necessary for pure PPPoE)

      ++ Bugfixes:

      2011-04-20: Simon Goldschmidt
      * sys_arch.txt: sys_arch_timeouts() is not needed any more.

      2011-04-13: Simon Goldschmidt
      * tcp.c, udp.c: Fixed bug #33048 (Bad range for IP source port numbers) by
        using ports in the IANA private/dynamic range (49152 through 65535).

      2011-03-29: Simon Goldschmidt, patch by Emil Lhungdahl:
      * etharp.h/.c: Fixed broken VLAN support.

      2011-03-27: Simon Goldschmidt
      * tcp.c: Fixed bug #32926 (TCP_RMV(&tcp_bound_pcbs) is called on unbound tcp
        pcbs) by checking if the pcb was bound (local_port != 0).

      2011-03-27: Simon Goldschmidt
      * ppp.c: Fixed bug #32280 (ppp: a pbuf is freed twice)

      2011-03-27: Simon Goldschmidt
      * sockets.c: Fixed bug #32906: lwip_connect+lwip_send did not work for udp and
        raw pcbs with LWIP_TCPIP_CORE_LOCKING==1.

      2011-03-27: Simon Goldschmidt
      * tcp_out.c: Fixed bug #32820 (Outgoing TCP connections created before route
        is present never times out) by starting retransmission timer before checking
        route.

      2011-03-22: Simon Goldschmidt
      * ppp.c: Fixed bug #32648 (PPP code crashes when terminating a link) by only
        calling sio_read_abort() if the file descriptor is valid.

      2011-03-14: Simon Goldschmidt
      * err.h/.c, sockets.c, api_msg.c: fixed bug #31748 (Calling non-blocking connect
        more than once can render a socket useless) since it mainly involves changing
        "FATAL" classification of error codes: ERR_USE and ERR_ISCONN just aren't fatal.

      2011-03-13: Simon Goldschmidt
      * sockets.c: fixed bug #32769 (ESHUTDOWN is linux-specific) by fixing
        err_to_errno_table (ERR_CLSD: ENOTCONN instead of ESHUTDOWN), ERR_ISCONN:
        use EALRADY instead of -1

      2011-03-13: Simon Goldschmidt
      * api_lib.c: netconn_accept: return ERR_ABRT instead of ERR_CLSD if the
        connection has been aborted by err_tcp (since this is not a normal closing
        procedure).

      2011-03-13: Simon Goldschmidt
      * tcp.c: tcp_bind: return ERR_VAL instead of ERR_ISCONN when trying to bind
        with pcb->state != CLOSED

      2011-02-17: Simon Goldschmidt
      * rawapi.txt: Fixed bug #32561 tcp_poll argument definition out-of-order in
        documentation

      2011-02-17: Simon Goldschmidt
      * many files: Added missing U/UL modifiers to fix 16-bit-arch portability.

      2011-01-24: Simon Goldschmidt
      * sockets.c: Fixed bug #31741: lwip_select seems to have threading problems

      2010-12-02: Simon Goldschmidt
      * err.h: Fixed ERR_IS_FATAL so that ERR_WOULDBLOCK is not fatal.

      2010-11-23: Simon Goldschmidt
      * api.h, api_lib.c, api_msg.c, sockets.c: netconn.recv_avail is only used for
        LWIP_SO_RCVBUF and ioctl/FIONREAD.

      2010-11-23: Simon Goldschmidt
      * etharp.c: Fixed bug #31720: ARP-queueing: RFC 1122 recommends to queue at
        least 1 packet -> ARP_QUEUEING==0 now queues the most recent packet.

      2010-11-23: Simon Goldschmidt
      * tcp_in.c: Fixed bug #30577: tcp_input: don't discard ACK-only packets after
        refusing 'refused_data' again.

      2010-11-22: Simon Goldschmidt
      * sockets.c: Fixed bug #31590: getsockopt(... SO_ERROR ...) gives EINPROGRESS
        after a successful nonblocking connection.

      2010-11-22: Simon Goldschmidt
      * etharp.c: Fixed bug #31722: IP packets sent with an AutoIP source addr
        must be sent link-local

      2010-11-22: Simon Goldschmidt
      * timers.c: patch #7329: tcp_timer_needed prototype was ifdef'ed out for
        LWIP_TIMERS==0

      2010-11-20: Simon Goldschmidt
      * sockets.c: Fixed bug #31170: lwip_setsockopt() does not set socket number

      2010-11-20: Simon Goldschmidt
      * sockets.h: Fixed bug #31304: Changed SHUT_RD, SHUT_WR and SHUT_RDWR to
        resemble other stacks.

      2010-11-20: Simon Goldschmidt
      * dns.c: Fixed bug #31535: TCP_SND_QUEUELEN must be at least 2 or else
        no-copy TCP writes will never succeed.

      2010-11-20: Simon Goldschmidt
      * dns.c: Fixed bug #31701: Error return value from dns_gethostbyname() does
        not match documentation: return ERR_ARG instead of ERR_VAL if not
        initialized or wrong argument.

      2010-10-20: Simon Goldschmidt
      * sockets.h: Fixed bug #31385: sizeof(struct sockaddr) is 30 but should be 16

      2010-10-05: Simon Goldschmidt
      * dhcp.c: Once again fixed #30038: DHCP/AutoIP cooperation failed when
        replugging the network cable after an AutoIP address was assigned.

      2010-08-10: Simon Goldschmidt
      * tcp.c: Fixed bug #30728: tcp_new_port() did not check listen pcbs

      2010-08-03: Simon Goldschmidt
      * udp.c, raw.c: Don't chain empty pbufs when sending them (fixes bug #30625)

      2010-08-01: Simon Goldschmidt (patch by Greg Renda)
      * ppp.c: Applied patch #7264 (PPP protocols are rejected incorrectly on big
        endian architectures)

      2010-07-28: Simon Goldschmidt
      * api_lib.c, api_msg.c, sockets.c, mib2.c: Fixed compilation with TCP or UDP
        disabled.

      2010-07-27: Simon Goldschmidt
      * tcp.c: Fixed bug #30565 (tcp_connect() check bound list): that check did no
        harm but never did anything

      2010-07-21: Simon Goldschmidt
      * ip.c: Fixed invalid fix for bug #30402 (CHECKSUM_GEN_IP_INLINE does not
        add IP options)

      2010-07-16: Kieran Mansley
      * msg_in.c: Fixed SNMP ASN constant defines to not use ! operator

      2010-07-10: Simon Goldschmidt
      * ip.c: Fixed bug #30402: CHECKSUM_GEN_IP_INLINE does not add IP options

      2010-06-30: Simon Goldschmidt
      * api_msg.c: fixed bug #30300 (shutdown parameter was not initialized in
        netconn_delete)

      2010-06-28: Kieran Mansley
      * timers.c remove unportable printing of C function pointers

      2010-06-24: Simon Goldschmidt
      * init.c, timers.c/.h, opt.h, memp_std.h: From patch #7221: added flag
        NO_SYS_NO_TIMERS to drop timer support for NO_SYS==1 for easier upgrading

      2010-06-24: Simon Goldschmidt
      * api(_lib).c/.h, api_msg.c/.h, sockets.c/.h: Fixed bug #10088: Correctly
        implemented shutdown at socket level.

      2010-06-21: Simon Goldschmidt
      * pbuf.c/.h, ip_frag.c/.h, opt.h, memp_std.h: Fixed bug #29361 (ip_frag has
        problems with zero-copy DMA MACs) by adding custom pbufs and implementing
        custom pbufs that reference other (original) pbufs. Additionally set
        IP_FRAG_USES_STATIC_BUF=0 as default to be on the safe side.

      2010-06-15: Simon Goldschmidt
      * dhcp.c: Fixed bug #29970: DHCP endian issue parsing option responses

      2010-06-14: Simon Goldschmidt
      * autoip.c: Fixed bug #30039: AutoIP does not reuse previous addresses

      2010-06-12: Simon Goldschmidt
      * dhcp.c: Fixed bug #30038: dhcp_network_changed doesn't reset AUTOIP coop
        state

      2010-05-17: Simon Goldschmidt
      * netdb.c: Correctly NULL-terminate h_addr_list

      2010-05-16: Simon Goldschmidt
      * def.h/.c: changed the semantics of LWIP_PREFIX_BYTEORDER_FUNCS to prevent
        "symbol already defined" i.e. when linking to winsock

      2010-05-05: Simon Goldschmidt
      * def.h, timers.c: Fixed bug #29769 (sys_check_timeouts: sys_now() may
        overflow)

      2010-04-21: Simon Goldschmidt
      * api_msg.c: Fixed bug #29617 (sometime cause stall on delete listening
        connection)

      2010-03-28: Luca Ceresoli
      * ip_addr.c/.h: patch #7143: Add a few missing const qualifiers

      2010-03-27: Luca Ceresoli
      * mib2.c: patch #7130: remove meaningless const qualifiers

      2010-03-26: Simon Goldschmidt
      * tcp_out.c: Make LWIP_NETIF_TX_SINGLE_PBUF work for TCP, too

      2010-03-26: Simon Goldschmidt
      * various files: Fixed compiling with different options disabled (TCP/UDP),
        triggered by bug #29345; don't allocate acceptmbox if LWIP_TCP is disabled

      2010-03-25: Simon Goldschmidt
      * sockets.c: Fixed bug #29332: lwip_select() processes readset incorrectly

      2010-03-25: Simon Goldschmidt
      * tcp_in.c, test_tcp_oos.c: Fixed bug #29080: Correctly handle remote side
        overrunning our rcv_wnd in ooseq case.

      2010-03-22: Simon Goldschmidt
      * tcp.c: tcp_listen() did not copy the pcb's prio.

      2010-03-19: Simon Goldschmidt
      * snmp_msg.c: Fixed bug #29256: SNMP Trap address was not correctly set

      2010-03-14: Simon Goldschmidt
      * opt.h, etharp.h: Fixed bug #29148 (Incorrect PBUF_POOL_BUFSIZE for ports
        where ETH_PAD_SIZE > 0) by moving definition of ETH_PAD_SIZE to opt.h
        and basing PBUF_LINK_HLEN on it.

      2010-03-08: Simon Goldschmidt
      * netif.c, ipv4/ip.c: task #10241 (AutoIP: don't break existing connections
        when assiging routable address): when checking incoming packets and
        aborting existing connection on address change, filter out link-local
        addresses.

      2010-03-06: Simon Goldschmidt
      * sockets.c: Fixed LWIP_NETIF_TX_SINGLE_PBUF for LWIP_TCPIP_CORE_LOCKING

      2010-03-06: Simon Goldschmidt
      * ipv4/ip.c: Don't try to forward link-local addresses

      2010-03-06: Simon Goldschmidt
      * etharp.c: Fixed bug #29087: etharp: don't send packets for LinkLocal-
        addresses to gw

      2010-03-05: Simon Goldschmidt
      * dhcp.c: Fixed bug #29072: Correctly set ciaddr based on message-type
        and state.

      2010-03-05: Simon Goldschmidt
      * api_msg.c: Correctly set TCP_WRITE_FLAG_MORE when netconn_write is split
        into multiple calls to tcp_write.

      2010-02-21: Simon Goldschmidt
      * opt.h, mem.h, dns.c: task #10140: Remove DNS_USES_STATIC_BUF (keep
        the implementation of DNS_USES_STATIC_BUF==1)

      2010-02-20: Simon Goldschmidt
      * tcp.h, tcp.c, tcp_in.c, tcp_out.c: Task #10088: Correctly implement
        close() vs. shutdown(). Now the application does not get any more
        recv callbacks after calling tcp_close(). Added tcp_shutdown().

      2010-02-19: Simon Goldschmidt
      * mem.c/.h, pbuf.c: Renamed mem_realloc() to mem_trim() to prevent
        confusion with realloc()

      2010-02-15: Simon Goldschmidt/Stephane Lesage
      * netif.c/.h: Link status does not depend on LWIP_NETIF_LINK_CALLBACK
        (fixes bug #28899)

      2010-02-14: Simon Goldschmidt
      * netif.c: Fixed bug #28877 (Duplicate ARP gratuitous packet with
        LWIP_NETIF_LINK_CALLBACK set on) by only sending if both link- and
        admin-status of a netif are up

      2010-02-14: Simon Goldschmidt
      * opt.h: Disable ETHARP_TRUST_IP_MAC by default since it slows down packet
        reception and is not really necessary

      2010-02-14: Simon Goldschmidt
      * etharp.c/.h: Fixed ARP input processing: only add a new entry if a
        request was directed as us (RFC 826, Packet Reception), otherwise
        only update existing entries; internalized some functions

      2010-02-14: Simon Goldschmidt
      * netif.h, etharp.c, tcpip.c: Fixed bug #28183 (ARP and TCP/IP cannot be
        disabled on netif used for PPPoE) by adding a new netif flag
        (NETIF_FLAG_ETHERNET) that tells the stack the device is an ethernet
        device but prevents usage of ARP (so that ethernet_input can be used
        for PPPoE).

      2010-02-12: Simon Goldschmidt
      * netif.c: netif_set_link_up/down: only do something if the link state
        actually changes

      2010-02-12: Simon Goldschmidt/Stephane Lesage
      * api_msg.c: Fixed bug #28865 (Cannot close socket/netconn in non-blocking
        connect)

      2010-02-12: Simon Goldschmidt
      * mem.h: Fixed bug #28866 (mem_realloc function defined in mem.h)

      2010-02-09: Simon Goldschmidt
      * api_lib.c, api_msg.c, sockets.c, api.h, api_msg.h: Fixed bug #22110
       (recv() makes receive window update for data that wasn't received by
        application)

      2010-02-09: Simon Goldschmidt/Stephane Lesage
      * sockets.c: Fixed bug #28853 (lwip_recvfrom() returns 0 on receive time-out
        or any netconn_recv() error)

      2010-02-09: Simon Goldschmidt
      * ppp.c: task #10154 (PPP: Update snmp in/out counters for tx/rx packets)

      2010-02-09: Simon Goldschmidt
      * netif.c: For loopback packets, adjust the stats- and snmp-counters
        for the loopback netif.

      2010-02-08: Simon Goldschmidt
      * igmp.c/.h, ip.h: Moved most defines from igmp.h to igmp.c for clarity
        since they are not used anywhere else.

      2010-02-08: Simon Goldschmidt (Stéphane Lesage)
      * igmp.c, igmp.h, stats.c, stats.h: Improved IGMP stats
        (patch from bug #28798)

      2010-02-08: Simon Goldschmidt (Stéphane Lesage)
      * igmp.c: Fixed bug #28798 (Error in "Max Response Time" processing) and
        another bug when LWIP_RAND() returns zero.

      2010-02-04: Simon Goldschmidt
      * nearly every file: Use macros defined in ip_addr.h (some of them new)
        to work with IP addresses (preparation for bug #27352 - Change ip_addr
        from struct to typedef (u32_t) - and better code).

      2010-01-31: Simon Goldschmidt
      * netif.c: Don't call the link-callback from netif_set_up/down() since
        this invalidly retriggers DHCP.

      2010-01-29: Simon Goldschmidt
      * ip_addr.h, inet.h, def.h, inet.c, def.c, more: Cleanly separate the
        portability file inet.h and its contents from the stack: moved htonX-
        functions to def.h (and the new def.c - they are not ipv4 dependent),
        let inet.h depend on ip_addr.h and not the other way round.
        This fixes bug #28732.

      2010-01-28: Kieran Mansley
      * tcp.c: Ensure ssthresh >= 2*MSS

      2010-01-27: Simon Goldschmidt
      * tcp.h, tcp.c, tcp_in.c: Fixed bug #27871: Calling tcp_abort() in recv
        callback can lead to accessing unallocated memory. As a consequence,
        ERR_ABRT means the application has called tcp_abort()!

      2010-01-25: Simon Goldschmidt
      * snmp_structs.h, msg_in.c: Partly fixed bug #22070 (MIB_OBJECT_WRITE_ONLY
        not implemented in SNMP): write-only or not-accessible are still
        returned by getnext (though not by get)

      2010-01-24: Simon Goldschmidt
      * snmp: Renamed the private mib node from 'private' to 'mib_private' to
        not use reserved C/C++ keywords

      2010-01-23: Simon Goldschmidt
      * sockets.c: Fixed bug #28716: select() returns 0 after waiting for less
        than 1 ms

      2010-01-21: Simon Goldschmidt
      * tcp.c, api_msg.c: Fixed bug #28651 (tcp_connect: no callbacks called
        if tcp_enqueue fails) both in raw- and netconn-API

      2010-01-19: Simon Goldschmidt
      * api_msg.c: Fixed bug #27316: netconn: Possible deadlock in err_tcp

      2010-01-18: Iordan Neshev/Simon Goldschmidt
      * src/netif/ppp: reorganised PPP sourcecode to 2.3.11 including some
        bugfix backports from 2.4.x.

      2010-01-18: Simon Goldschmidt
      * mem.c: Fixed bug #28679: mem_realloc calculates mem_stats wrong

      2010-01-17: Simon Goldschmidt
      * api_lib.c, api_msg.c, (api_msg.h, api.h, sockets.c, tcpip.c):
        task #10102: "netconn: clean up conn->err threading issues" by adding
        error return value to struct api_msg_msg

      2010-01-17: Simon Goldschmidt
      * api.h, api_lib.c, sockets.c: Changed netconn_recv() and netconn_accept()
        to return err_t (bugs #27709 and #28087)

      2010-01-14: Simon Goldschmidt
      * ...: Use typedef for function prototypes throughout the stack.

      2010-01-13: Simon Goldschmidt
      * api_msg.h/.c, api_lib.c: Fixed bug #26672 (close connection when receive
        window = 0) by correctly draining recvmbox/acceptmbox

      2010-01-11: Simon Goldschmidt
      * pap.c: Fixed bug #13315 (PPP PAP authentication can result in
        erroneous callbacks) by copying the code from recent pppd

      2010-01-10: Simon Goldschmidt
      * raw.c: Fixed bug #28506 (raw_bind should filter received packets)

      2010-01-10: Simon Goldschmidt
      * tcp.h/.c: bug #28127 (remove call to tcp_output() from tcp_ack(_now)())

      2010-01-08: Simon Goldschmidt
      * sockets.c: Fixed bug #28519 (lwip_recvfrom bug with len > 65535)

      2010-01-08: Simon Goldschmidt
      * dns.c: Copy hostname for DNS_LOCAL_HOSTLIST_IS_DYNAMIC==1 since string
        passed to dns_local_addhost() might be volatile

      2010-01-07: Simon Goldschmidt
      * timers.c, tcp.h: Call tcp_timer_needed() with NO_SYS==1, too

      2010-01-06: Simon Goldschmidt
      * netdb.h: Fixed bug #28496: missing include guards in netdb.h

      2009-12-31: Simon Goldschmidt
      * many ppp files: Reorganised PPP source code from ucip structure to pppd
        structure to easily compare our code against the pppd code (around v2.3.1)

      2009-12-27: Simon Goldschmidt
      * tcp_in.c: Another fix for bug #28241 (ooseq processing) and adapted
        unit test

    (STABLE-1.3.2)

      ++ New features:

      2009-10-27 Simon Goldschmidt/Stephan Lesage
      * netifapi.c/.h: Added netifapi_netif_set_addr()

      2009-10-07 Simon Goldschmidt/Fabian Koch
      * api_msg.c, netbuf.c/.h, opt.h: patch #6888: Patch for UDP Netbufs to
        support dest-addr and dest-port (optional: LWIP_NETBUF_RECVINFO)

      2009-08-26 Simon Goldschmidt/Simon Kallweit
      * slipif.c/.h: bug #26397: SLIP polling support

      2009-08-25 Simon Goldschmidt
      * opt.h, etharp.h/.c: task #9033: Support IEEE 802.1q tagged frame (VLAN),
        New configuration options ETHARP_SUPPORT_VLAN and ETHARP_VLAN_CHECK.

      2009-08-25 Simon Goldschmidt
      * ip_addr.h, netdb.c: patch #6900: added define ip_ntoa(struct ip_addr*)

      2009-08-24 Jakob Stoklund Olesen
      * autoip.c, dhcp.c, netif.c: patch #6725: Teach AutoIP and DHCP to respond
        to netif_set_link_up().

      2009-08-23 Simon Goldschmidt
      * tcp.h/.c: Added function tcp_debug_state_str() to convert a tcp state
        to a human-readable string.

      ++ Bugfixes:

      2009-12-24: Kieran Mansley
      * tcp_in.c Apply patches from Oleg Tyshev to improve OOS processing
        (BUG#28241)

      2009-12-06: Simon Goldschmidt
      * ppp.h/.c: Fixed bug #27079 (Yet another leak in PPP): outpacket_buf can
        be statically allocated (like in ucip)

      2009-12-04: Simon Goldschmidt (patch by Ioardan Neshev)
      * pap.c: patch #6969: PPP: missing PAP authentication UNTIMEOUT

      2009-12-03: Simon Goldschmidt
      * tcp.h, tcp_in.c, tcp_out.c: Fixed bug #28106: dup ack for fast retransmit
        could have non-zero length

      2009-12-02: Simon Goldschmidt
      * tcp_in.c: Fixed bug #27904: TCP sends too many ACKs: delay resetting
        tcp_input_pcb until after calling the pcb's callbacks

      2009-11-29: Simon Goldschmidt
      * tcp_in.c: Fixed bug #28054: Two segments with FIN flag on the out-of-
        sequence queue, also fixed PBUF_POOL leak in the out-of-sequence code

      2009-11-29: Simon Goldschmidt
      * pbuf.c: Fixed bug #28064: pbuf_alloc(PBUF_POOL) is not thread-safe by
        queueing a call into tcpip_thread to free ooseq-bufs if the pool is empty

      2009-11-26: Simon Goldschmidt
      * tcp.h: Fixed bug #28098: Nagle can prevent fast retransmit from sending
        segment

      2009-11-26: Simon Goldschmidt
      * tcp.h, sockets.c: Fixed bug #28099: API required to disable Nagle
        algorithm at PCB level

      2009-11-22: Simon Goldschmidt
      * tcp_out.c: Fixed bug #27905: FIN isn't combined with data on unsent

      2009-11-22: Simon Goldschmidt (suggested by Bill Auerbach)
      * tcp.c: tcp_alloc: prevent increasing stats.err for MEMP_TCP_PCB when
        reusing time-wait pcb

      2009-11-20: Simon Goldschmidt (patch by Albert Bartel)
      * sockets.c: Fixed bug #28062: Data received directly after accepting
        does not wake up select

      2009-11-11: Simon Goldschmidt
      * netdb.h: Fixed bug #27994: incorrect define for freeaddrinfo(addrinfo)

      2009-10-30: Simon Goldschmidt
      * opt.h: Increased default value for TCP_MSS to 536, updated default
        value for TCP_WND to 4*TCP_MSS to keep delayed ACK working.

      2009-10-28: Kieran Mansley
      * tcp_in.c, tcp_out.c, tcp.h: re-work the fast retransmission code
        to follow algorithm from TCP/IP Illustrated

      2009-10-27: Kieran Mansley
      * tcp_in.c: fix BUG#27445: grow cwnd with every duplicate ACK

      2009-10-25: Simon Goldschmidt
      * tcp.h: bug-fix in the TCP_EVENT_RECV macro (has to call tcp_recved if
        pcb->recv is NULL to keep rcv_wnd correct)

      2009-10-25: Simon Goldschmidt
      * tcp_in.c: Fixed bug #26251: RST process in TIME_WAIT TCP state

      2009-10-23: Simon Goldschmidt (David Empson)
      * tcp.c: Fixed bug #27783: Silly window avoidance for small window sizes

      2009-10-21: Simon Goldschmidt
      * tcp_in.c: Fixed bug #27215: TCP sent() callback gives leading and
        trailing 1 byte len (SYN/FIN)

      2009-10-21: Simon Goldschmidt
      * tcp_out.c: Fixed bug #27315: zero window probe and FIN

      2009-10-19: Simon Goldschmidt
      * dhcp.c/.h: Minor code simplification (don't store received pbuf, change
        conditional code to assert where applicable), check pbuf length before
        testing for valid reply

      2009-10-19: Simon Goldschmidt
      * dhcp.c: Removed most calls to udp_connect since they aren't necessary
        when using udp_sendto_if() - always stay connected to IP_ADDR_ANY.

      2009-10-16: Simon Goldschmidt
      * ip.c: Fixed bug #27390: Source IP check in ip_input() causes it to drop
        valid DHCP packets -> allow 0.0.0.0 as source address when LWIP_DHCP is
        enabled

      2009-10-15: Simon Goldschmidt (Oleg Tyshev)
      * tcp_in.c: Fixed bug #27329: dupacks by unidirectional data transmit

      2009-10-15: Simon Goldschmidt
      * api_lib.c: Fixed bug #27709: conn->err race condition on netconn_recv()
        timeout

      2009-10-15: Simon Goldschmidt
      * autoip.c: Fixed bug #27704: autoip starts with wrong address
        LWIP_AUTOIP_CREATE_SEED_ADDR() returned address in host byte order instead
        of network byte order

      2009-10-11 Simon Goldschmidt (Jörg Kesten)
      * tcp_out.c: Fixed bug #27504: tcp_enqueue wrongly concatenates segments
        which are not consecutive when retransmitting unacked segments

      2009-10-09 Simon Goldschmidt
      * opt.h: Fixed default values of some stats to only be enabled if used
        Fixes bug #27338: sys_stats is defined when NO_SYS = 1

      2009-08-30 Simon Goldschmidt
      * ip.c: Fixed bug bug #27345: "ip_frag() does not use the LWIP_NETIF_LOOPBACK
        function" by checking for loopback before calling ip_frag

      2009-08-25 Simon Goldschmidt
      * dhcp.c: fixed invalid dependency to etharp_query if DHCP_DOES_ARP_CHECK==0

      2009-08-23 Simon Goldschmidt
      * ppp.c: bug #27078: Possible memory leak in pppInit()

      2009-08-23 Simon Goldschmidt
      * netdb.c, dns.c: bug #26657: DNS, if host name is "localhost", result
        is error.

      2009-08-23 Simon Goldschmidt
      * opt.h, init.c: bug #26649: TCP fails when TCP_MSS > TCP_SND_BUF
        Fixed wrong parenthesis, added check in init.c

      2009-08-23 Simon Goldschmidt
      * ppp.c: bug #27266: wait-state debug message in pppMain occurs every ms

      2009-08-23 Simon Goldschmidt
      * many ppp files: bug #27267: Added include to string.h where needed

      2009-08-23 Simon Goldschmidt
      * tcp.h: patch #6843: tcp.h macro optimization patch (for little endian)

    (STABLE-1.3.1)

      ++ New features:

      2009-05-10 Simon Goldschmidt
      * opt.h, sockets.c, pbuf.c, netbuf.h, pbuf.h: task #7013: Added option
        LWIP_NETIF_TX_SINGLE_PBUF to try to create transmit packets from only
        one pbuf to help MACs that don't support scatter-gather DMA.

      2009-05-09 Simon Goldschmidt
      * icmp.h, icmp.c: Shrinked ICMP code, added option to NOT check icoming
        ECHO pbuf for size (just use it): LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN

      2009-05-05 Simon Goldschmidt, Jakob Stoklund Olesen
      * ip.h, ip.c: Added ip_current_netif() & ip_current_header() to receive
        extended info about the currently received packet.

      2009-04-27 Simon Goldschmidt
      * sys.h: Made SYS_LIGHTWEIGHT_PROT and sys_now() work with NO_SYS=1

      2009-04-25 Simon Goldschmidt
      * mem.c, opt.h: Added option MEM_USE_POOLS_TRY_BIGGER_POOL to try the next
        bigger malloc pool if one is empty (only usable with MEM_USE_POOLS).

      2009-04-21 Simon Goldschmidt
      * dns.c, init.c, dns.h, opt.h: task #7507, patch #6786: DNS supports static
        hosts table. New configuration options DNS_LOCAL_HOSTLIST and
        DNS_LOCAL_HOSTLIST_IS_DYNAMIC. Also, DNS_LOOKUP_LOCAL_EXTERN() can be defined
        as an external function for lookup.

      2009-04-15 Simon Goldschmidt
      * dhcp.c: patch #6763: Global DHCP XID can be redefined to something more unique

      2009-03-31 Kieran Mansley
      * tcp.c, tcp_out.c, tcp_in.c, sys.h, tcp.h, opts.h: add support for
        TCP timestamp options, off by default.  Rework tcp_enqueue() to
        take option flags rather than specified option data

      2009-02-18 Simon Goldschmidt
      * cc.h: Added printf formatter for size_t: SZT_F

      2009-02-16 Simon Goldschmidt (patch by Rishi Khan)
      * icmp.c, opt.h: patch #6539: (configurable) response to broadcast- and multicast
        pings

      2009-02-12 Simon Goldschmidt
      * init.h: Added LWIP_VERSION to get the current version of the stack

      2009-02-11 Simon Goldschmidt (suggested by Gottfried Spitaler)
      * opt.h, memp.h/.c: added MEMP_MEM_MALLOC to use mem_malloc/mem_free instead
        of the pool allocator (can save code size with MEM_LIBC_MALLOC if libc-malloc
        is otherwise used)

      2009-01-28 Jonathan Larmour (suggested by Bill Bauerbach)
      * ipv4/inet_chksum.c, ipv4/lwip/inet_chksum.h: inet_chksum_pseudo_partial()
      is only used by UDPLITE at present, so conditionalise it.

      2008-12-03 Simon Goldschmidt (base on patch from Luca Ceresoli)
      * autoip.c: checked in (slightly modified) patch #6683: Customizable AUTOIP
        "seed" address. This should reduce AUTOIP conflicts if
        LWIP_AUTOIP_CREATE_SEED_ADDR is overridden.

      2008-10-02 Jonathan Larmour and Rishi Khan
      * sockets.c (lwip_accept): Return EWOULDBLOCK if would block on non-blocking
        socket.

      2008-06-30 Simon Goldschmidt
      * mem.c, opt.h, stats.h: fixed bug #21433: Calling mem_free/pbuf_free from
        interrupt context isn't safe: LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT allows
        mem_free to run between mem_malloc iterations. Added illegal counter for
        mem stats.

      2008-06-27 Simon Goldschmidt
      * stats.h/.c, some other files: patch #6483: stats module improvement:
        Added defines to display each module's statistic individually, added stats
        defines for MEM, MEMP and SYS modules, removed (unused) rexmit counter.

      2008-06-17 Simon Goldschmidt
      * err.h: patch #6459: Made err_t overridable to use a more efficient type
        (define LWIP_ERR_T in cc.h)

      2008-06-17 Simon Goldschmidt
      * slipif.c: patch #6480: Added a configuration option for slipif for symmetry
        to loopif

      2008-06-17 Simon Goldschmidt (patch by Luca Ceresoli)
      * netif.c, loopif.c, ip.c, netif.h, loopif.h, opt.h: Checked in slightly
        modified version of patch # 6370: Moved loopif code to netif.c so that
        loopback traffic is supported on all netifs (all local IPs).
        Added option to limit loopback packets for each netifs.

      ++ Bugfixes:
      2009-08-12 Kieran Mansley
      * tcp_in.c, tcp.c: Fix bug #27209: handle trimming of segments when
        out of window or out of order properly

      2009-08-12 Kieran Mansley
      * tcp_in.c: Fix bug #27199: use snd_wl2 instead of snd_wl1

      2009-07-28 Simon Goldschmidt
      * mem.h: Fixed bug #27105: "realloc() cannot replace mem_realloc()"s

      2009-07-27 Kieran Mansley
      * api.h api_msg.h netdb.h sockets.h: add missing #include directives

      2009-07-09 Kieran Mansley
      * api_msg.c, sockets.c, api.h: BUG23240 use signed counters for
        recv_avail and don't increment counters until message successfully
        sent to mbox

      2009-06-25 Kieran Mansley
      * api_msg.c api.h: BUG26722: initialise netconn write variables
        in netconn_alloc

      2009-06-25 Kieran Mansley
      * tcp.h: BUG26879: set ret value in TCP_EVENT macros when function is not set

      2009-06-25 Kieran Mansley
      * tcp.c, tcp_in.c, tcp_out.c, tcp.h: BUG26301 and BUG26267: correct
        simultaneous close behaviour, and make snd_nxt have the same meaning
        as in the RFCs.

      2009-05-12 Simon Goldschmidt
      * etharp.h, etharp.c, netif.c: fixed bug #26507: "Gratuitous ARP depends on
        arp_table / uses etharp_query" by adding etharp_gratuitous()

      2009-05-12 Simon Goldschmidt
      * ip.h, ip.c, igmp.c: bug #26487: Added ip_output_if_opt that can add IP options
        to the IP header (used by igmp_ip_output_if)

      2009-05-06 Simon Goldschmidt
      * inet_chksum.c: On little endian architectures, use LWIP_PLATFORM_HTONS (if
        defined) for SWAP_BYTES_IN_WORD to speed up checksumming.

      2009-05-05 Simon Goldschmidt
      * sockets.c: bug #26405: Prematurely released semaphore causes lwip_select()
        to crash

      2009-05-04 Simon Goldschmidt
      * init.c: snmp was not initialized in lwip_init()

      2009-05-04 Frédéric Bernon
      * dhcp.c, netbios.c: Changes if IP_SOF_BROADCAST is enabled.

      2009-05-03 Simon Goldschmidt
      * tcp.h: bug #26349: Nagle algorithm doesn't send although segment is full
        (and unsent->next == NULL)

      2009-05-02 Simon Goldschmidt
      * tcpip.h, tcpip.c: fixed tcpip_untimeout (does not need the time, broken after
        1.3.0 in CVS only) - fixes compilation of ppp_oe.c

      2009-05-02 Simon Goldschmidt
      * msg_in.c: fixed bug #25636: SNMPSET value is ignored for integer fields

      2009-05-01 Simon Goldschmidt
      * pap.c: bug #21680: PPP upap_rauthnak() drops legal NAK packets

      2009-05-01 Simon Goldschmidt
      * ppp.c: bug #24228: Memory corruption with PPP and DHCP

      2009-04-29 Frédéric Bernon
      * raw.c, udp.c, init.c, opt.h, ip.h, sockets.h: bug #26309: Implement the
        SO(F)_BROADCAST filter for all API layers. Avoid the unindented reception
        of broadcast packets even when this option wasn't set. Port maintainers
        which want to enable this filter have to set IP_SOF_BROADCAST=1 in opt.h.
        If you want this option also filter broadcast on recv operations, you also
        have to set IP_SOF_BROADCAST_RECV=1 in opt.h.

      2009-04-28 Simon Goldschmidt, Jakob Stoklund Olesen
      * dhcp.c: patch #6721, bugs #25575, #25576: Some small fixes to DHCP and
        DHCP/AUTOIP cooperation

      2009-04-25 Simon Goldschmidt, Oleg Tyshev
      * tcp_out.c: bug #24212: Deadlocked tcp_retransmit due to exceeded pcb->cwnd
        Fixed by sorting the unsent and unacked queues (segments are inserted at the
        right place in tcp_output and tcp_rexmit).

      2009-04-25 Simon Goldschmidt
      * memp.c, mem.c, memp.h, mem_std.h: bug #26213 "Problem with memory allocation
        when debugging": memp_sizes contained the wrong sizes (including sanity
        regions); memp pools for MEM_USE_POOLS were too small

      2009-04-24 Simon Goldschmidt, Frédéric Bernon
      * inet.c: patch #6765: Fix a small problem with the last changes (incorrect
        behavior, with with ip address string not ended by a '\0', a space or a
        end of line)

      2009-04-19 Simon Goldschmidt
      * rawapi.txt: Fixed bug #26069: Corrected documentation: if tcp_connect fails,
        pcb->err is called, not pcb->connected (with an error code).

      2009-04-19 Simon Goldschmidt
      * tcp_out.c: Fixed bug #26236: "TCP options (timestamp) don't work with
        no-copy-tcpwrite": deallocate option data, only concat segments with same flags

      2009-04-19 Simon Goldschmidt
      * tcp_out.c: Fixed bug #25094: "Zero-length pbuf" (options are now allocated
        in the header pbuf, not the data pbuf)

      2009-04-18 Simon Goldschmidt
      * api_msg.c: fixed bug #25695: Segmentation fault in do_writemore()

      2009-04-15 Simon Goldschmidt
      * sockets.c: tried to fix bug #23559: lwip_recvfrom problem with tcp

      2009-04-15 Simon Goldschmidt
      * dhcp.c: task #9192: mem_free of dhcp->options_in and dhcp->msg_in

      2009-04-15 Simon Goldschmidt
      * ip.c, ip6.c, tcp_out.c, ip.h: patch #6808: Add a utility function
        ip_hinted_output() (for smaller code mainly)

      2009-04-15 Simon Goldschmidt
      * inet.c: patch #6765: Supporting new line characters in inet_aton()

      2009-04-15 Simon Goldschmidt
      * dhcp.c: patch #6764: DHCP rebind and renew did not send hostnam option;
        Converted constant OPTION_MAX_MSG_SIZE to netif->mtu, check if netif->mtu
        is big enough in dhcp_start

      2009-04-15 Simon Goldschmidt
      * netbuf.c: bug #26027: netbuf_chain resulted in pbuf memory leak

      2009-04-15 Simon Goldschmidt
      * sockets.c, ppp.c: bug #25763: corrected 4 occurrences of SMEMCPY to MEMCPY

      2009-04-15 Simon Goldschmidt
      * sockets.c: bug #26121: set_errno can be overridden

      2009-04-09 Kieran Mansley (patch from Luca Ceresoli <lucaceresoli>)
      * init.c, opt.h: Patch#6774 TCP_QUEUE_OOSEQ breaks compilation when
        LWIP_TCP==0

      2009-04-09 Kieran Mansley (patch from Roy Lee <roylee17>)
      * tcp.h: Patch#6802 Add do-while-clauses to those function like
        macros in tcp.h

      2009-03-31 Kieran Mansley
      * tcp.c, tcp_in.c, tcp_out.c, tcp.h, opt.h: Rework the way window
        updates are calculated and sent (BUG20515)

      * tcp_in.c: cope with SYN packets received during established states,
        and retransmission of initial SYN.

      * tcp_out.c: set push bit correctly when tcp segments are merged

      2009-03-27 Kieran Mansley
      * tcp_out.c set window correctly on probes (correcting change made
        yesterday)

      2009-03-26 Kieran Mansley
      * tcp.c, tcp_in.c, tcp.h: add tcp_abandon() to cope with dropping
        connections where no reset required (bug #25622)

      * tcp_out.c: set TCP_ACK flag on keepalive and zero window probes
        (bug #20779)

      2009-02-18 Simon Goldschmidt (Jonathan Larmour and Bill Auerbach)
      * ip_frag.c: patch #6528: the buffer used for IP_FRAG_USES_STATIC_BUF could be
        too small depending on MEM_ALIGNMENT

      2009-02-16 Simon Goldschmidt
      * sockets.h/.c, api_*.h/.c: fixed arguments of socket functions to match the standard;
        converted size argument of netconn_write to 'size_t'

      2009-02-16 Simon Goldschmidt
      * tcp.h, tcp.c: fixed bug #24440: TCP connection close problem on 64-bit host
        by moving accept callback function pointer to TCP_PCB_COMMON

      2009-02-12 Simon Goldschmidt
      * dhcp.c: fixed bug #25345 (DHCPDECLINE is sent with "Maximum message size"
        option)

      2009-02-11 Simon Goldschmidt
      * dhcp.c: fixed bug #24480 (releasing old udp_pdb and pbuf in dhcp_start)

      2009-02-11 Simon Goldschmidt
      * opt.h, api_msg.c: added configurable default valud for netconn->recv_bufsize:
        RECV_BUFSIZE_DEFAULT (fixes bug #23726: pbuf pool exhaustion on slow recv())

      2009-02-10 Simon Goldschmidt
      * tcp.c: fixed bug #25467: Listen backlog is not reset on timeout in SYN_RCVD:
        Accepts_pending is decrease on a corresponding listen pcb when a connection
        in state SYN_RCVD is close.

      2009-01-28 Jonathan Larmour
      * pbuf.c: reclaim pbufs from TCP out-of-sequence segments if we run
        out of pool pbufs.

      2008-12-19 Simon Goldschmidt
      * many files: patch #6699: fixed some warnings on platform where sizeof(int) == 2

      2008-12-10 Tamas Somogyi, Frédéric Bernon
      * sockets.c: fixed bug #25051: lwip_recvfrom problem with udp: fromaddr and
        port uses deleted netbuf.

      2008-10-18 Simon Goldschmidt
      * tcp_in.c: fixed bug ##24596: Vulnerability on faulty TCP options length
        in tcp_parseopt

      2008-10-15 Simon Goldschmidt
      * ip_frag.c: fixed bug #24517: IP reassembly crashes on unaligned IP headers
        by packing the struct ip_reass_helper.

      2008-10-03 David Woodhouse, Jonathan Larmour
      * etharp.c (etharp_arp_input): Fix type aliasing problem copying ip address.

      2008-10-02 Jonathan Larmour
      * dns.c: Hard-code structure sizes, to avoid issues on some compilers where
        padding is included.

      2008-09-30 Jonathan Larmour
      * sockets.c (lwip_accept): check addr isn't NULL. If it's valid, do an
        assertion check that addrlen isn't NULL.

      2008-09-30 Jonathan Larmour
      * tcp.c: Fix bug #24227, wrong error message in tcp_bind.

      2008-08-26 Simon Goldschmidt
      * inet.h, ip_addr.h: fixed bug #24132: Cross-dependency between ip_addr.h and
        inet.h -> moved declaration of struct in_addr from ip_addr.h to inet.h

      2008-08-14 Simon Goldschmidt
      * api_msg.c: fixed bug #23847: do_close_internal references freed memory (when
        tcp_close returns != ERR_OK)

      2008-07-08 Frédéric Bernon
      * stats.h: Fix some build bugs introduced with patch #6483 (missing some parameters
        in macros, mainly if MEM_STATS=0 and MEMP_STATS=0).

      2008-06-24 Jonathan Larmour
      * tcp_in.c: Fix for bug #23693 as suggested by Art R. Ensure cseg is unused
        if tcp_seg_copy fails.

      2008-06-17 Simon Goldschmidt
      * inet_chksum.c: Checked in some ideas of patch #6460 (loop optimizations)
        and created defines for swapping bytes and folding u32 to u16.

      2008-05-30 Kieran Mansley
      * tcp_in.c Remove redundant "if" statement, and use real rcv_wnd
        rather than rcv_ann_wnd when deciding if packets are in-window.
        Contributed by <arasmussen@consultant.datasys.swri.edu>

      2008-05-30 Kieran Mansley
      * mem.h: Fix BUG#23254.  Change macro definition of mem_* to allow
        passing as function pointers when MEM_LIBC_MALLOC is defined.

      2008-05-09 Jonathan Larmour
      * err.h, err.c, sockets.c: Fix bug #23119: Reorder timeout error code to
        stop it being treated as a fatal error.

      2008-04-15 Simon Goldschmidt
      * dhcp.c: fixed bug #22804: dhcp_stop doesn't clear NETIF_FLAG_DHCP
        (flag now cleared)

      2008-03-27 Simon Goldschmidt
      * mem.c, tcpip.c, tcpip.h, opt.h: fixed bug #21433 (Calling mem_free/pbuf_free
        from interrupt context isn't safe): set LWIP_USE_HEAP_FROM_INTERRUPT to 1
        in lwipopts.h or use pbuf_free_callback(p)/mem_free_callback(m) to free pbufs
        or heap memory from interrupt context

      2008-03-26 Simon Goldschmidt
      * tcp_in.c, tcp.c: fixed bug #22249: division by zero could occur if a remote
        host sent a zero mss as TCP option.

    (STABLE-1.3.0)

      ++ New features:

      2008-03-10 Jonathan Larmour
      * inet_chksum.c: Allow choice of one of the sample algorithms to be
        made from lwipopts.h. Fix comment on how to override LWIP_CHKSUM.

      2008-01-22 Frédéric Bernon
      * tcp.c, tcp_in.c, tcp.h, opt.h: Rename LWIP_CALCULATE_EFF_SEND_MSS in
        TCP_CALCULATE_EFF_SEND_MSS to have coherent TCP options names.

      2008-01-14 Frédéric Bernon
      * rawapi.txt, api_msg.c, tcp.c, tcp_in.c, tcp.h: changes for task #7675 "Enable
        to refuse data on a TCP_EVENT_RECV call". Important, behavior changes for the
        tcp_recv callback (see rawapi.txt).

      2008-01-14 Frédéric Bernon, Marc Chaland
      * ip.c: Integrate patch #6369" ip_input : checking before realloc".

      2008-01-12 Frédéric Bernon
      * tcpip.h, tcpip.c, api.h, api_lib.c, api_msg.c, sockets.c: replace the field
        netconn::sem per netconn::op_completed like suggested for the task #7490
        "Add return value to sys_mbox_post".

      2008-01-12 Frédéric Bernon
      * api_msg.c, opt.h: replace DEFAULT_RECVMBOX_SIZE per DEFAULT_TCP_RECVMBOX_SIZE,
        DEFAULT_UDP_RECVMBOX_SIZE and DEFAULT_RAW_RECVMBOX_SIZE (to optimize queues
        sizes), like suggested for the task #7490 "Add return value to sys_mbox_post".

      2008-01-10 Frédéric Bernon
      * tcpip.h, tcpip.c: add tcpip_callback_with_block function for the task #7490
        "Add return value to sys_mbox_post". tcpip_callback is always defined as
        "blocking" ("block" parameter = 1).

      2008-01-10 Frédéric Bernon
      * tcpip.h, tcpip.c, api.h, api_lib.c, api_msg.c, sockets.c: replace the field
        netconn::mbox (sys_mbox_t) per netconn::sem (sys_sem_t) for the task #7490
        "Add return value to sys_mbox_post".

      2008-01-05 Frédéric Bernon
      * sys_arch.txt, api.h, api_lib.c, api_msg.h, api_msg.c, tcpip.c, sys.h, opt.h:
        Introduce changes for task #7490 "Add return value to sys_mbox_post" with some
        modifications in the sys_mbox api: sys_mbox_new take a "size" parameters which
        indicate the number of pointers query by the mailbox. There is three defines
        in opt.h to indicate sizes for tcpip::mbox, netconn::recvmbox, and for the
        netconn::acceptmbox. Port maintainers, you can decide to just add this new
        parameter in your implementation, but to ignore it to keep the previous behavior.
        The new sys_mbox_trypost function return a value to know if the mailbox is
        full or if the message is posted. Take a look to sys_arch.txt for more details.
        This new function is used in tcpip_input (so, can be called in an interrupt
        context since the function is not blocking), and in recv_udp and recv_raw.

      2008-01-04 Frédéric Bernon, Simon Goldschmidt, Jonathan Larmour
      * rawapi.txt, api.h, api_lib.c, api_msg.h, api_msg.c, sockets.c, tcp.h, tcp.c,
        tcp_in.c, init.c, opt.h: rename backlog options with TCP_ prefix, limit the
        "backlog" parameter in an u8_t, 0 is interpreted as "smallest queue", add
        documentation in the rawapi.txt file.

      2007-12-31 Kieran Mansley (based on patch from Per-Henrik Lundbolm)
      * tcp.c, tcp_in.c, tcp_out.c, tcp.h: Add TCP persist timer

      2007-12-31 Frédéric Bernon, Luca Ceresoli
      * autoip.c, etharp.c: ip_addr.h: Integrate patch #6348: "Broadcast ARP packets
        in autoip". The change in etharp_raw could be removed, since all calls to
        etharp_raw use ethbroadcast for the "ethdst_addr" parameter. But it could be
        wrong in the future.

      2007-12-30 Frédéric Bernon, Tom Evans
      * ip.c: Fix bug #21846 "LwIP doesn't appear to perform any IP Source Address
        Filtering" reported by Tom Evans.

      2007-12-21 Frédéric Bernon, Simon Goldschmidt, Jonathan Larmour
      * tcp.h, opt.h, api.h, api_msg.h, tcp.c, tcp_in.c, api_lib.c, api_msg.c,
        sockets.c, init.c: task #7252: Implement TCP listen backlog: Warning: raw API
        applications have to call 'tcp_accepted(pcb)' in their accept callback to
        keep accepting new connections.

      2007-12-13 Frédéric Bernon
      * api_msg.c, err.h, err.c, sockets.c, dns.c, dns.h: replace "enum dns_result"
        by err_t type. Add a new err_t code "ERR_INPROGRESS".

      2007-12-12 Frédéric Bernon
      * dns.h, dns.c, opt.h: move DNS options to the "right" place. Most visibles
        are the one which have ram usage.

      2007-12-05 Frédéric Bernon
      * netdb.c: add a LWIP_DNS_API_HOSTENT_STORAGE option to decide to use a static
        set of variables (=0) or a local one (=1). In this last case, your port should
        provide a function "struct hostent* sys_thread_hostent( struct hostent* h)"
        which have to do a copy of "h" and return a pointer ont the "per-thread" copy.

      2007-12-03 Simon Goldschmidt
      * ip.c: ip_input: check if a packet is for inp first before checking all other
        netifs on netif_list (speeds up packet receiving in most cases)

      2007-11-30 Simon Goldschmidt
      * udp.c, raw.c: task #7497: Sort lists (pcb, netif, ...) for faster access
        UDP: move a (connected) pcb selected for input to the front of the list of
        pcbs so that it is found faster next time. Same for RAW pcbs that have eaten
        a packet.

      2007-11-28 Simon Goldschmidt
      * etharp.c, stats.c, stats.h, opt.h: Introduced ETHARP_STATS

      2007-11-25 Simon Goldschmidt
      * dhcp.c: dhcp_unfold_reply() uses pbuf_copy_partial instead of its own copy
        algorithm.

      2007-11-24 Simon Goldschmidt
      * netdb.h, netdb.c, sockets.h/.c: Moved lwip_gethostbyname from sockets.c
        to the new file netdb.c; included lwip_getaddrinfo.

      2007-11-21 Simon Goldschmidt
      * tcp.h, opt.h, tcp.c, tcp_in.c: implemented calculating the effective send-mss
        based on the MTU of the netif used to send. Enabled by default. Disable by
        setting LWIP_CALCULATE_EFF_SEND_MSS to 0. This fixes bug #21492.

      2007-11-19 Frédéric Bernon
      * api_msg.c, dns.h, dns.c: Implement DNS_DOES_NAME_CHECK option (check if name
        received match the name query), implement DNS_USES_STATIC_BUF (the place where
        copy dns payload to parse the response), return an error if there is no place
        for a new query, and fix some minor problems.

      2007-11-16 Simon Goldschmidt
      * new files: ipv4/inet.c, ipv4/inet_chksum.c, ipv6/inet6.c
        removed files: core/inet.c, core/inet6.c
        Moved inet files into ipv4/ipv6 directory; splitted inet.c/inet.h into
        inet and chksum part; changed includes in all lwIP files as appropriate

      2007-11-16 Simon Goldschmidt
      * api.h, api_msg.h, api_lib.c, api_msg.c, socket.h, socket.c: Added sequential
        dns resolver function for netconn api (netconn_gethostbyname) and socket api
        (gethostbyname/gethostbyname_r).

      2007-11-15 Jim Pettinato, Frédéric Bernon
      * opt.h, init.c, tcpip.c, dhcp.c, dns.h, dns.c: add DNS client for simple name
        requests with RAW api interface. Initialization is done in lwip_init() with
        build time options. DNS timer is added in tcpip_thread context. DHCP can set
        DNS server ip addresses when options are received. You need to set LWIP_DNS=1
        in your lwipopts.h file (LWIP_DNS=0 in opt.h). DNS_DEBUG can be set to get
        some traces with LWIP_DEBUGF. Sanity check have been added. There is a "todo"
        list with points to improve.

      2007-11-06 Simon Goldschmidt
      * opt.h, mib2.c: Patch #6215: added ifAdminStatus write support (if explicitly
        enabled by defining SNMP_SAFE_REQUESTS to 0); added code to check link status
        for ifOperStatus if LWIP_NETIF_LINK_CALLBACK is defined.

      2007-11-06 Simon Goldschmidt
      * api.h, api_msg.h and dependent files: Task #7410: Removed the need to include
        core header files in api.h (ip/tcp/udp/raw.h) to hide the internal
        implementation from netconn api applications.

      2007-11-03 Frédéric Bernon
      * api.h, api_lib.c, api_msg.c, sockets.c, opt.h: add SO_RCVBUF option for UDP &
        RAW netconn. You need to set LWIP_SO_RCVBUF=1 in your lwipopts.h (it's disabled
        by default). Netconn API users can use the netconn_recv_bufsize macro to access
        it. This is a first release which have to be improve for TCP. Note it used the
        netconn::recv_avail which need to be more "thread-safe" (note there is already
        the problem for FIONREAD with lwip_ioctl/ioctlsocket).

      2007-11-01 Frédéric Bernon, Marc Chaland
      * sockets.h, sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c, tcp.h, tcp_out.c:
        Integrate "patch #6250 : MSG_MORE flag for send". MSG_MORE is used at socket api
        layer, NETCONN_MORE at netconn api layer, and TCP_WRITE_FLAG_MORE at raw api
        layer. This option enable to delayed TCP PUSH flag on multiple "write" calls.
        Note that previous "copy" parameter for "write" APIs is now called "apiflags".

      2007-10-24 Frédéric Bernon
      * api.h, api_lib.c, api_msg.c: Add macro API_EVENT in the same spirit than
        TCP_EVENT_xxx macros to get a code more readable. It could also help to remove
        some code (like we have talk in "patch #5919 : Create compile switch to remove
        select code"), but it could be done later.

      2007-10-08 Simon Goldschmidt
      * many files: Changed initialization: many init functions are not needed any
        more since we now rely on the compiler initializing global and static
        variables to zero!

      2007-10-06 Simon Goldschmidt
      * ip_frag.c, memp.c, mib2.c, ip_frag.h, memp_std.h, opt.h: Changed IP_REASSEMBLY
        to enqueue the received pbufs so that multiple packets can be reassembled
        simultaneously and no static reassembly buffer is needed.

      2007-10-05 Simon Goldschmidt
      * tcpip.c, etharp.h, etharp.c: moved ethernet_input from tcpip.c to etharp.c so
        all netifs (or ports) can use it.

      2007-10-05 Frédéric Bernon
      * netifapi.h, netifapi.c: add function netifapi_netif_set_default. Change the
        common function to reduce a little bit the footprint (for all functions using
        only the "netif" parameter).

      2007-10-03 Frédéric Bernon
      * netifapi.h, netifapi.c: add functions netifapi_netif_set_up, netifapi_netif_set_down,
        netifapi_autoip_start and netifapi_autoip_stop. Use a common function to reduce
        a little bit the footprint (for all functions using only the "netif" parameter).

      2007-09-15 Frédéric Bernon
      * udp.h, udp.c, sockets.c: Changes for "#20503 IGMP Improvement". Add IP_MULTICAST_IF
        option in socket API, and a new field "multicast_ip" in "struct udp_pcb" (for
        netconn and raw API users), only if LWIP_IGMP=1. Add getsockopt processing for
        IP_MULTICAST_TTL and IP_MULTICAST_IF.

      2007-09-10 Frédéric Bernon
      * snmp.h, mib2.c: enable to remove SNMP timer (which consumne several cycles
        even when it's not necessary). snmp_agent.txt tell to call snmp_inc_sysuptime()
        each 10ms (but, it's intrusive if you use sys_timeout feature). Now, you can
        decide to call snmp_add_sysuptime(100) each 1000ms (which is bigger "step", but
        call to a lower frequency). Or, you can decide to not call snmp_inc_sysuptime()
        or snmp_add_sysuptime(), and to define the SNMP_GET_SYSUPTIME(sysuptime) macro.
        This one is undefined by default in mib2.c. SNMP_GET_SYSUPTIME is called inside
        snmp_get_sysuptime(u32_t *value), and enable to change "sysuptime" value only
        when it's queried (any direct call to "sysuptime" is changed by a call to
        snmp_get_sysuptime).

      2007-09-09 Frédéric Bernon, Bill Florac
      * igmp.h, igmp.c, netif.h, netif.c, ip.c: To enable to have interfaces with IGMP,
        and others without it, there is a new NETIF_FLAG_IGMP flag to set in netif->flags
        if you want IGMP on an interface. igmp_stop() is now called inside netif_remove().
        igmp_report_groups() is now called inside netif_set_link_up() (need to have
        LWIP_NETIF_LINK_CALLBACK=1) to resend reports once the link is up (avoid to wait
        the next query message to receive the matching multicast streams).

      2007-09-08 Frédéric Bernon
      * sockets.c, ip.h, api.h, tcp.h: declare a "struct ip_pcb" which only contains
        IP_PCB. Add in the netconn's "pcb" union a "struct ip_pcb *ip;" (no size change).
        Use this new field to access to common pcb fields (ttl, tos, so_options, etc...).
        Enable to access to these fields with LWIP_TCP=0.

      2007-09-05 Frédéric Bernon
      * udp.c, ipv4/icmp.c, ipv4/ip.c, ipv6/icmp.c, ipv6/ip6.c, ipv4/icmp.h,
        ipv6/icmp.h, opt.h: Integrate "task #7272 : LWIP_ICMP option". The new option
        LWIP_ICMP enable/disable ICMP module inside the IP stack (enable per default).
        Be careful, disabling ICMP make your product non-compliant to RFC1122, but
        help to reduce footprint, and to reduce "visibility" on the Internet.

      2007-09-05 Frédéric Bernon, Bill Florac
      * opt.h, sys.h, tcpip.c, slipif.c, ppp.c, sys_arch.txt: Change parameters list
        for sys_thread_new (see "task #7252 : Create sys_thread_new_ex()"). Two new
        parameters have to be provided: a task name, and a task stack size. For this
        one, since it's platform dependant, you could define the best one for you in
        your lwipopts.h. For port maintainers, you can just add these new parameters
        in your sys_arch.c file, and but it's not mandatory, use them in your OS
        specific functions.

      2007-09-05 Frédéric Bernon
      * inet.c, autoip.c, msg_in.c, msg_out.c, init.c: Move some build time checkings
        inside init.c for task #7142 "Sanity check user-configurable values".

      2007-09-04 Frédéric Bernon, Bill Florac
      * igmp.h, igmp.c, memp_std.h, memp.c, init.c, opt.h: Replace mem_malloc call by
        memp_malloc, and use a new MEMP_NUM_IGMP_GROUP option (see opt.h to define the
        value). It will avoid potential fragmentation problems, use a counter to know
        how many times a group is used on an netif, and free it when all applications
        leave it. MEMP_NUM_IGMP_GROUP got 8 as default value (and init.c got a sanity
        check if LWIP_IGMP!=0).

      2007-09-03 Frédéric Bernon
      * igmp.h, igmp.c, sockets.c, api_msg.c: Changes for "#20503 IGMP Improvement".
        Initialize igmp_mac_filter to NULL in netif_add (this field should be set in
        the netif's "init" function). Use the "imr_interface" field (for socket layer)
        and/or the "interface" field (for netconn layer), for join/leave operations.
        The igmp_join/leavegroup first parameter change from a netif to an ipaddr.
        This field could be a netif's ipaddr, or "any" (same meaning than ip_addr_isany).

      2007-08-30 Frédéric Bernon
      * Add netbuf.h, netbuf.c, Change api.h, api_lib.c: #7249 "Split netbuf functions
        from api/api_lib". Now netbuf API is independant of netconn, and can be used
        with other API (application based on raw API, or future "socket2" API). Ports
        maintainers just have to add src/api/netbuf.c in their makefile/projects.

      2007-08-30 Frédéric Bernon, Jonathan Larmour
      * init.c: Add first version of lwip_sanity_check for task #7142 "Sanity check
        user-configurable values".

      2007-08-29 Frédéric Bernon
      * igmp.h, igmp.c, tcpip.c, init.c, netif.c: change igmp_init and add igmp_start.
        igmp_start is call inside netif_add. Now, igmp initialization is in the same
        spirit than the others modules. Modify some IGMP debug traces.

      2007-08-29 Frédéric Bernon
      * Add init.h, init.c, Change opt.h, tcpip.c: Task  #7213 "Add a lwip_init function"
        Add lwip_init function to regroup all modules initializations, and to provide
        a place to add code for task #7142 "Sanity check user-configurable values".
        Ports maintainers should remove direct initializations calls from their code,
        and add init.c in their makefiles. Note that lwip_init() function is called
        inside tcpip_init, but can also be used by raw api users since all calls are
        disabled when matching options are disabled. Also note that their is new options
        in opt.h, you should configure in your lwipopts.h (they are enabled per default).

      2007-08-26 Marc Boucher
      * api_msg.c: do_close_internal(): Reset the callbacks and arg (conn) to NULL
        since they can under certain circumstances be called with an invalid conn
        pointer after the connection has been closed (and conn has been freed).

      2007-08-25 Frédéric Bernon (Artem Migaev's Patch)
      * netif.h, netif.c: Integrate "patch #6163 : Function to check if link layer is up".
        Add a netif_is_link_up() function if LWIP_NETIF_LINK_CALLBACK option is set.

      2007-08-22 Frédéric Bernon
      * netif.h, netif.c, opt.h: Rename LWIP_NETIF_CALLBACK in LWIP_NETIF_STATUS_CALLBACK
        to be coherent with new LWIP_NETIF_LINK_CALLBACK option before next release.

      2007-08-22 Frédéric Bernon
      * tcpip.h, tcpip.c, ethernetif.c, opt.h: remove options ETHARP_TCPIP_INPUT &
        ETHARP_TCPIP_ETHINPUT, now, only "ethinput" code is supported, even if the
        name is tcpip_input (we keep the name of 1.2.0 function).

      2007-08-17 Jared Grubb
      * memp_std.h, memp.h, memp.c, mem.c, stats.c: (Task #7136) Centralize mempool
        settings into new memp_std.h and optional user file lwippools.h. This adds
        more dynamic mempools, and allows the user to create an arbitrary number of
        mempools for mem_malloc.

      2007-08-16 Marc Boucher
      * api_msg.c: Initialize newconn->state to NETCONN_NONE in accept_function;
        otherwise it was left to NETCONN_CLOSE and sent_tcp() could prematurely
        close the connection.

      2007-08-16 Marc Boucher
      * sockets.c: lwip_accept(): check netconn_peer() error return.

      2007-08-16 Marc Boucher
      * mem.c, mem.h: Added mem_calloc().

      2007-08-16 Marc Boucher
      * tcpip.c, tcpip.h memp.c, memp.h: Added distinct memp (MEMP_TCPIP_MSG_INPKT)
        for input packets to prevent floods from consuming all of MEMP_TCPIP_MSG
        and starving other message types.
        Renamed MEMP_TCPIP_MSG to MEMP_TCPIP_MSG_API

      2007-08-16 Marc Boucher
      * pbuf.c, pbuf.h, etharp.c, tcp_in.c, sockets.c: Split pbuf flags in pbuf
        type and flgs (later renamed to flags).
        Use enum pbuf_flag as pbuf_type.  Renumber PBUF_FLAG_*.
        Improved lwip_recvfrom().  TCP push now propagated.

      2007-08-16 Marc Boucher
      * ethernetif.c, contrib/ports/various: ethbroadcast now a shared global
        provided by etharp.

      2007-08-16 Marc Boucher
      * ppp_oe.c ppp_oe.h, auth.c chap.c fsm.c lcp.c ppp.c ppp.h,
        etharp.c ethernetif.c, etharp.h, opt.h tcpip.h, tcpip.c:
        Added PPPoE support and various PPP improvements.

      2007-07-25 Simon Goldschmidt
      * api_lib.c, ip_frag.c, pbuf.c, api.h, pbuf.h: Introduced pbuf_copy_partial,
        making netbuf_copy_partial use this function.

      2007-07-25 Simon Goldschmidt
      * tcp_in.c: Fix bug #20506: Slow start / initial congestion window starts with
        2 * mss (instead of 1 * mss previously) to comply with some newer RFCs and
        other stacks.

      2007-07-13 Jared Grubb (integrated by Frédéric Bernon)
      * opt.h, netif.h, netif.c, ethernetif.c: Add new configuration option to add
        a link callback in the netif struct, and functions to handle it. Be carefull
        for port maintainers to add the NETIF_FLAG_LINK_UP flag (like in ethernetif.c)
        if you want to be sure to be compatible with future changes...

      2007-06-30 Frédéric Bernon
      * sockets.h, sockets.c: Implement MSG_PEEK flag for recv/recvfrom functions.

      2007-06-21 Simon Goldschmidt
      * etharp.h, etharp.c: Combined etharp_request with etharp_raw for both
        LWIP_AUTOIP =0 and =1 to remove redundant code.

      2007-06-21 Simon Goldschmidt
      * mem.c, memp.c, mem.h, memp.h, opt.h: task #6863: Introduced the option
        MEM_USE_POOLS to use 4 pools with different sized elements instead of a
        heap. This both prevents memory fragmentation and gives a higher speed
        at the cost of more memory consumption. Turned off by default.

      2007-06-21 Simon Goldschmidt
      * api_lib.c, api_msg.c, api.h, api_msg.h: Converted the length argument of
        netconn_write (and therefore also api_msg_msg.msg.w.len) from u16_t into
        int to be able to send a bigger buffer than 64K with one time (mainly
        used from lwip_send).

      2007-06-21 Simon Goldschmidt
      * tcp.h, api_msg.c: Moved the nagle algorithm from netconn_write/do_write
        into a define (tcp_output_nagle) in tcp.h to provide it to raw api users, too.

      2007-06-21 Simon Goldschmidt
      * api.h, api_lib.c, api_msg.c: Fixed bug #20021: Moved sendbuf-processing in
        netconn_write from api_lib.c to api_msg.c to also prevent multiple context-
        changes on low memory or empty send-buffer.

      2007-06-18 Simon Goldschmidt
      * etharp.c, etharp.h: Changed etharp to use a defined hardware address length
        of 6 to avoid loading netif->hwaddr_len every time (since this file is only
        used for ethernet and struct eth_addr already had a defined length of 6).

      2007-06-17 Simon Goldschmidt
      * sockets.c, sockets.h: Implemented socket options SO_NO_CHECK for UDP sockets
        to disable UDP checksum generation on transmit.

      2007-06-13 Frédéric Bernon, Simon Goldschmidt
      * debug.h, api_msg.c: change LWIP_ERROR to use it to check errors like invalid
        pointers or parameters, and let the possibility to redefined it in cc.h. Use
        this macro to check "conn" parameter in api_msg.c functions.

      2007-06-11 Simon Goldschmidt
      * sockets.c, sockets.h: Added UDP lite support for sockets

      2007-06-10 Simon Goldschmidt
      * udp.h, opt.h, api_msg.c, ip.c, udp.c: Included switch LWIP_UDPLITE (enabled
        by default) to switch off UDP-Lite support if not needed (reduces udp.c code
        size)

      2007-06-09 Dominik Spies (integrated by Frédéric Bernon)
      * autoip.h, autoip.c, dhcp.h, dhcp.c, netif.h, netif.c, etharp.h, etharp.c, opt.h:
        AutoIP implementation available for IPv4, with new options LWIP_AUTOIP and
        LWIP_DHCP_AUTOIP_COOP if you want to cooperate with DHCP. Some tips to adapt
        (see TODO mark in the source code).

      2007-06-09 Simon Goldschmidt
      * etharp.h, etharp.c, ethernetif.c: Modified order of parameters for
        etharp_output() to match netif->output so etharp_output() can be used
        directly as netif->output to save one function call.

      2007-06-08 Simon Goldschmidt
      * netif.h, ethernetif.c, slipif.c, loopif.c: Added define
        NETIF_INIT_SNMP(netif, type, speed) to initialize per-netif snmp variables,
        added initialization of those to ethernetif, slipif and loopif.

      2007-05-18 Simon Goldschmidt
      * opt.h, ip_frag.c, ip_frag.h, ip.c: Added option IP_FRAG_USES_STATIC_BUF
        (defaulting to off for now) that can be set to 0 to send fragmented
        packets by passing PBUF_REFs down the stack.

      2007-05-23 Frédéric Bernon
      * api_lib.c: Implement SO_RCVTIMEO for accept and recv on TCP
        connections, such present in patch #5959.

      2007-05-23 Frédéric Bernon
      * api.h, api_lib.c, api_msg.c, sockets.c: group the different NETCONN_UDPxxx
        code in only one part...

      2007-05-18 Simon Goldschmidt
      * opt.h, memp.h, memp.c: Added option MEMP_OVERFLOW_CHECK to check for memp
        elements to overflow. This is achieved by adding some bytes before and after
        each pool element (increasing their size, of course), filling them with a
        prominent value and checking them on freeing the element.
        Set it to 2 to also check every element in every pool each time memp_malloc()
        or memp_free() is called (slower but more helpful).

      2007-05-10 Simon Goldschmidt
      * opt.h, memp.h, memp.c, pbuf.c (see task #6831): use a new memp pool for
        PBUF_POOL pbufs instead of the old pool implementation in pbuf.c to reduce
        code size.

      2007-05-11 Frédéric Bernon
      * sockets.c, api_lib.c, api_msg.h, api_msg.c, netifapi.h, netifapi.c, tcpip.c:
        Include a function pointer instead of a table index in the message to reduce
        footprint. Disable some part of lwip_send and lwip_sendto if some options are
        not set (LWIP_TCP, LWIP_UDP, LWIP_RAW).

      2007-05-10 Simon Goldschmidt
      * *.h (except netif/ppp/*.h): Included patch #5448: include '#ifdef __cplusplus
        \ extern "C" {' in all header files. Now you can write your application using
        the lwIP stack in C++ and simply #include the core files. Note I have left
        out the netif/ppp/*h header files for now, since I don't know which files are
        included by applications and which are for internal use only.

      2007-05-09 Simon Goldschmidt
      * opt.h, *.c/*.h: Included patch #5920: Create define to override C-library
        memcpy. 2 Defines are created: MEMCPY() for normal memcpy, SMEMCPY() for
        situations where some compilers might inline the copy and save a function
        call. Also replaced all calls to memcpy() with calls to (S)MEMCPY().

      2007-05-08 Simon Goldschmidt
      * mem.h: If MEM_LIBC_MALLOC==1, allow the defines (e.g. mem_malloc() -> malloc())
        to be overriden in case the C-library malloc implementation is not protected
        against concurrent access.

      2007-05-04 Simon Goldschmidt (Atte Kojo)
      * etharp.c: Introduced fast one-entry-cache to speed up ARP lookup when sending
        multiple packets to the same host.

      2007-05-04 Frédéric Bernon, Jonathan Larmour
      * sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c: Fix bug #19162 "lwip_sento: a possible
        to corrupt remote addr/port connection state". Reduce problems "not enought memory" with
        netbuf (if we receive lot of datagrams). Improve lwip_sendto (only one exchange between
        sockets api and api_msg which run in tcpip_thread context). Add netconn_sento function.
        Warning, if you directly access to "fromaddr" & "fromport" field from netbuf struct,
        these fields are now renamed "addr" & "port".

      2007-04-11 Jonathan Larmour
      * sys.h, api_lib.c: Provide new sys_mbox_tryfetch function. Require ports to provide new
        sys_arch_mbox_tryfetch function to get a message if one is there, otherwise return
        with SYS_MBOX_EMPTY. sys_arch_mbox_tryfetch can be implemented as a function-like macro
        by the port in sys_arch.h if desired.

      2007-04-06 Frédéric Bernon, Simon Goldschmidt
      * opt.h, tcpip.h, tcpip.c, netifapi.h, netifapi.c: New configuration option LWIP_NETIF_API
        allow to use thread-safe functions to add/remove netif in list, and to start/stop dhcp
        clients, using new functions from netifapi.h. Disable as default (no port change to do).

      2007-04-05 Frédéric Bernon
      * sockets.c: remplace ENOBUFS errors on alloc_socket by ENFILE to be more BSD compliant.

      2007-04-04 Simon Goldschmidt
      * arch.h, api_msg.c, dhcp.c, msg_in.c, sockets.c: Introduced #define LWIP_UNUSED_ARG(x)
        use this for and architecture-independent form to tell the compiler you intentionally
        are not using this variable. Can be overriden in cc.h.

      2007-03-28 Frédéric Bernon
      * opt.h, netif.h, dhcp.h, dhcp.c: New configuration option LWIP_NETIF_HOSTNAME allow to
        define a hostname in netif struct (this is just a pointer, so, you can use a hardcoded
        string, point on one of your's ethernetif field, or alloc a string you will free yourself).
        It will be used by DHCP to register a client hostname, but can also be use when you call
        snmp_set_sysname.

      2007-03-28 Frédéric Bernon
      * netif.h, netif.c: A new NETIF_FLAG_ETHARP flag is defined in netif.h, to allow to
        initialize a network interface's flag with. It tell this interface is an ethernet
        device, and we can use ARP with it to do a "gratuitous ARP" (RFC 3220 "IP Mobility
        Support for IPv4" section 4.6) when interface is "up" with netif_set_up().

      2007-03-26 Frédéric Bernon, Jonathan Larmour
      * opt.h, tcpip.c: New configuration option LWIP_ARP allow to disable ARP init at build
        time if you only use PPP or SLIP. The default is enable. Note we don't have to call
        etharp_init in your port's initilization sequence if you use tcpip.c, because this call
        is done in tcpip_init function.

      2007-03-22 Frédéric Bernon
      * stats.h, stats.c, msg_in.c: Stats counters can be change to u32_t if necessary with the
        new option LWIP_STATS_LARGE. If you need this option, define LWIP_STATS_LARGE to 1 in
        your lwipopts.h. More, unused counters are not defined in the stats structs, and not
        display by stats_display(). Note that some options (SYS_STATS and RAW_STATS) are defined
        but never used. Fix msg_in.c with the correct #if test for a stat display.

      2007-03-21 Kieran Mansley
      * netif.c, netif.h: Apply patch#4197 with some changes (originator: rireland@hmgsl.com).
        Provides callback on netif up/down state change.

      2007-03-11 Frédéric Bernon, Mace Gael, Steve Reynolds
      * sockets.h, sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c, igmp.h, igmp.c,
        ip.c, netif.h, tcpip.c, opt.h:
        New configuration option LWIP_IGMP to enable IGMP processing. Based on only one
        filter per all network interfaces. Declare a new function in netif to enable to
        control the MAC filter (to reduce lwIP traffic processing).

      2007-03-11 Frédéric Bernon
      * tcp.h, tcp.c, sockets.c, tcp_out.c, tcp_in.c, opt.h: Keepalive values can
        be configured at run time with LWIP_TCP_KEEPALIVE, but don't change this
        unless you know what you're doing (default are RFC1122 compliant). Note
        that TCP_KEEPIDLE and TCP_KEEPINTVL have to be set in seconds.

      2007-03-08 Frédéric Bernon
      * tcp.h: Keepalive values can be configured at compile time, but don't change
        this unless you know what you're doing (default are RFC1122 compliant).

      2007-03-08 Frédéric Bernon
      * sockets.c, api.h, api_lib.c, tcpip.c, sys.h, sys.c, err.c, opt.h:
        Implement LWIP_SO_RCVTIMEO configuration option to enable/disable SO_RCVTIMEO
        on UDP sockets/netconn.

      2007-03-08 Simon Goldschmidt
      * snmp_msg.h, msg_in.c: SNMP UDP ports can be configured at compile time.

      2007-03-06 Frédéric Bernon
      * api.h, api_lib.c, sockets.h, sockets.c, tcpip.c, sys.h, sys.c, err.h:
        Implement SO_RCVTIMEO on UDP sockets/netconn.

      2007-02-28 Kieran Mansley (based on patch from Simon Goldschmidt)
      * api_lib.c, tcpip.c, memp.c, memp.h: make API msg structs allocated
        on the stack and remove the API msg type from memp

      2007-02-26 Jonathan Larmour (based on patch from Simon Goldschmidt)
      * sockets.h, sockets.c: Move socket initialization to new
        lwip_socket_init() function.
        NOTE: this changes the API with ports. Ports will have to be
        updated to call lwip_socket_init() now.

      2007-02-26 Jonathan Larmour (based on patch from Simon Goldschmidt)
      * api_lib.c: Use memcpy in netbuf_copy_partial.

      ++ Bug fixes:

      2008-03-17 Frédéric Bernon, Ed Kerekes
      * igmp.h, igmp.c: Fix bug #22613 "IGMP iphdr problem" (could have
        some problems to fill the IP header on some targets, use now the
        ip.h macros to do it).

      2008-03-13 Frédéric Bernon
      * sockets.c: Fix bug #22435 "lwip_recvfrom with TCP break;". Using
        (lwip_)recvfrom with valid "from" and "fromlen" parameters, on a
        TCP connection caused a crash. Note that using (lwip_)recvfrom
        like this is a bit slow and that using (lwip)getpeername is the
        good lwip way to do it (so, using recv is faster on tcp sockets).

      2008-03-12 Frédéric Bernon, Jonathan Larmour
      * api_msg.c, contrib/apps/ping.c: Fix bug #22530 "api_msg.c's
        recv_raw() does not consume data", and the ping sample (with
        LWIP_SOCKET=1, the code did the wrong supposition that lwip_recvfrom
        returned the IP payload, without the IP header).

      2008-03-04 Jonathan Larmour
      * mem.c, stats.c, mem.h: apply patch #6414 to avoid compiler errors
      and/or warnings on some systems where mem_size_t and size_t differ.
      * pbuf.c, ppp.c: Fix warnings on some systems with mem_malloc.

      2008-03-04 Kieran Mansley (contributions by others)
      * Numerous small compiler error/warning fixes from contributions to
        mailing list after 1.3.0 release candidate made.

      2008-01-25 Cui hengbin (integrated by Frédéric Bernon)
      * dns.c: Fix bug #22108 "DNS problem" caused by unaligned structures.

      2008-01-15 Kieran Mansley
      * tcp_out.c: BUG20511.  Modify persist timer to start when we are
        prevented from sending by a small send window, not just a zero
        send window.

      2008-01-09 Jonathan Larmour
      * opt.h, ip.c: Rename IP_OPTIONS define to IP_OPTIONS_ALLOWED to avoid
        conflict with Linux system headers.

      2008-01-06 Jonathan Larmour
      * dhcp.c: fix bug #19927: "DHCP NACK problem" by clearing any existing set IP
        address entirely on receiving a DHCPNAK, and restarting discovery.

      2007-12-21 Simon Goldschmidt
      * sys.h, api_lib.c, api_msg.c, sockets.c: fix bug #21698: "netconn->recv_avail
        is not protected" by using new macros for interlocked access to modify/test
        netconn->recv_avail.

      2007-12-20 Kieran Mansley (based on patch from Oleg Tyshev)
      * tcp_in.c: fix bug# 21535 (nrtx not reset correctly in SYN_SENT state)

      2007-12-20 Kieran Mansley (based on patch from Per-Henrik Lundbolm)
      * tcp.c, tcp_in.c, tcp_out.c, tcp.h: fix bug #20199 (better handling
        of silly window avoidance and prevent lwIP from shrinking the window)

      2007-12-04 Simon Goldschmidt
      * tcp.c, tcp_in.c: fix bug #21699 (segment leak in ooseq processing when last
        data packet was lost): add assert that all segment lists are empty in
        tcp_pcb_remove before setting pcb to CLOSED state; don't directly set CLOSED
        state from LAST_ACK in tcp_process

      2007-12-02 Simon Goldschmidt
      * sockets.h: fix bug #21654: exclude definition of struct timeval from #ifndef FD_SET
        If including <sys/time.h> for system-struct timeval, LWIP_TIMEVAL_PRIVATE now
        has to be set to 0 in lwipopts.h

      2007-12-02 Simon Goldschmidt
      * api_msg.c, api_lib.c: fix bug #21656 (recvmbox problem in netconn API): always
        allocate a recvmbox in netconn_new_with_proto_and_callback. For a tcp-listen
        netconn, this recvmbox is later freed and a new mbox is allocated for acceptmbox.
        This is a fix for thread-safety and allocates all items needed for a netconn
        when the netconn is created.

      2007-11-30 Simon Goldschmidt
      * udp.c: first attempt to fix bug #21655 (DHCP doesn't work reliably with multiple
        netifs): if LWIP_DHCP is enabled, UDP packets to DHCP_CLIENT_PORT are passed
        to netif->dhcp->pcb only (if that exists) and not to any other pcb for the same
        port (only solution to let UDP pcbs 'bind' to a netif instead of an IP address)

      2007-11-27 Simon Goldschmidt
      * ip.c: fixed bug #21643 (udp_send/raw_send don't fail if netif is down) by
        letting ip_route only use netifs that are up.

      2007-11-27 Simon Goldschmidt
      * err.h, api_lib.c, api_msg.c, sockets.c: Changed error handling: ERR_MEM, ERR_BUF
        and ERR_RTE are seen as non-fatal, all other errors are fatal. netconns and
        sockets block most operations once they have seen a fatal error.

      2007-11-27 Simon Goldschmidt
      * udp.h, udp.c, dhcp.c: Implemented new function udp_sendto_if which takes the
        netif to send as an argument (to be able to send on netifs that are down).

      2007-11-26 Simon Goldschmidt
      * tcp_in.c: Fixed bug #21582: pcb->acked accounting can be wrong when ACKs
        arrive out-of-order

      2007-11-21 Simon Goldschmidt
      * tcp.h, tcp_out.c, api_msg.c: Fixed bug #20287: tcp_output_nagle sends too early
        Fixed the nagle algorithm; nagle now also works for all raw API applications
        and has to be explicitly disabled with 'tcp_pcb->flags |= TF_NODELAY'

      2007-11-12 Frédéric Bernon
      * sockets.c, api.h, api_lib.c, api_msg.h, api_msg.c: Fixed bug #20900. Now, most
        of the netconn_peer and netconn_addr processing is done inside tcpip_thread
        context in do_getaddr.

      2007-11-10 Simon Goldschmidt
      * etharp.c: Fixed bug: assert fired when MEMP_ARP_QUEUE was empty (which can
        happen any time). Now the packet simply isn't enqueued when out of memory.

      2007-11-01 Simon Goldschmidt
      * tcp.c, tcp_in.c: Fixed bug #21494: The send mss (pcb->mss) is set to 536 (or
        TCP_MSS if that is smaller) as long as no MSS option is received from the
        remote host.

      2007-11-01 Simon Goldschmidt
      * tcp.h, tcp.c, tcp_in.c: Fixed bug #21491: The MSS option sent (with SYN)
        is now based on TCP_MSS instead of pcb->mss (on passive open now effectively
        sending our configured TCP_MSS instead of the one received).

      2007-11-01 Simon Goldschmidt
      * tcp_in.c: Fixed bug #21181: On active open, the initial congestion window was
        calculated based on the configured TCP_MSS, not on the MSS option received
        with SYN+ACK.

      2007-10-09 Simon Goldschmidt
      * udp.c, inet.c, inet.h: Fixed UDPLite: send: Checksum was always generated too
        short and also was generated wrong if checksum coverage != tot_len;
        receive: checksum was calculated wrong if checksum coverage != tot_len

      2007-10-08 Simon Goldschmidt
      * mem.c: lfree was not updated in mem_realloc!

      2007-10-07 Frédéric Bernon
      * sockets.c, api.h, api_lib.c: First step to fix "bug #20900 : Potential
        crash error problem with netconn_peer & netconn_addr". VERY IMPORTANT:
        this change cause an API breakage for netconn_addr, since a parameter
        type change. Any compiler should cause an error without any changes in
        yours netconn_peer calls (so, it can't be a "silent change"). It also
        reduce a little bit the footprint for socket layer (lwip_getpeername &
        lwip_getsockname use now a common lwip_getaddrname function since
        netconn_peer & netconn_addr have the same parameters).

      2007-09-20 Simon Goldschmidt
      * tcp.c: Fixed bug #21080 (tcp_bind without check pcbs in TIME_WAIT state)
        by checking  tcp_tw_pcbs also

      2007-09-19 Simon Goldschmidt
      * icmp.c: Fixed bug #21107 (didn't reset IP TTL in ICMP echo replies)

      2007-09-15 Mike Kleshov
      * mem.c: Fixed bug #21077 (inaccuracy in calculation of lwip_stat.mem.used)

      2007-09-06 Frédéric Bernon
      * several-files: replace some #include "arch/cc.h" by "lwip/arch.h", or simply remove
        it as long as "lwip/opt.h" is included before (this one include "lwip/debug.h" which
        already include "lwip/arch.h"). Like that, default defines are provided by "lwip/arch.h"
        if they are not defined in cc.h, in the same spirit than "lwip/opt.h" for lwipopts.h.

      2007-08-30 Frédéric Bernon
      * igmp.h, igmp.c: Some changes to remove some redundant code, add some traces,
        and fix some coding style.

      2007-08-28 Frédéric Bernon
      * tcpip.c: Fix TCPIP_MSG_INPKT processing: now, tcpip_input can be used for any
        kind of packets. These packets are considered like Ethernet packets (payload
        pointing to ethhdr) if the netif got the NETIF_FLAG_ETHARP flag. Else, packets
        are considered like IP packets (payload pointing to iphdr).

      2007-08-27 Frédéric Bernon
      * api.h, api_lib.c, api_msg.c: First fix for "bug #20900 : Potential crash error
        problem with netconn_peer & netconn_addr". Introduce NETCONN_LISTEN netconn_state
        and remove obsolete ones (NETCONN_RECV & NETCONN_ACCEPT).

      2007-08-24 Kieran Mansley
      * inet.c Modify (acc >> 16) test to ((acc >> 16) != 0) to help buggy
        compiler (Paradigm C++)

      2007-08-09 Frédéric Bernon, Bill Florac
      * stats.h, stats.c, igmp.h, igmp.c, opt.h: Fix for bug #20503 : IGMP Improvement.
        Introduce IGMP_STATS to centralize statistics management.

      2007-08-09 Frédéric Bernon, Bill Florac
      * udp.c: Fix for bug #20503 : IGMP Improvement. Enable to receive a multicast
        packet on a udp pcb binded on an netif's IP address, and not on "any".

      2007-08-09 Frédéric Bernon, Bill Florac
      * igmp.h, igmp.c, ip.c: Fix minor changes from bug #20503 : IGMP Improvement.
        This is mainly on using lookup/lookfor, and some coding styles...

      2007-07-26 Frédéric Bernon (and "thedoctor")
      * igmp.c: Fix bug #20595 to accept IGMPv3 "Query" messages.

      2007-07-25 Simon Goldschmidt
      * api_msg.c, tcp.c: Another fix for bug #20021: by not returning an error if
        tcp_output fails in tcp_close, the code in do_close_internal gets simpler
        (tcp_output is called again later from tcp timers).

      2007-07-25 Simon Goldschmidt
      * ip_frag.c: Fixed bug #20429: use the new pbuf_copy_partial instead of the old
        copy_from_pbuf, which illegally modified the given pbuf.

      2007-07-25 Simon Goldschmidt
      * tcp_out.c: tcp_enqueue: pcb->snd_queuelen didn't work for chaine PBUF_RAMs:
        changed snd_queuelen++ to snd_queuelen += pbuf_clen(p).

      2007-07-24 Simon Goldschmidt
      * api_msg.c, tcp.c: Fix bug #20480: Check the pcb passed to tcp_listen() for the
        correct state (must be CLOSED).

      2007-07-13 Thomas Taranowski (commited by Jared Grubb)
      * memp.c: Fix bug #20478: memp_malloc returned NULL+MEMP_SIZE on failed
        allocation. It now returns NULL.

      2007-07-13 Frédéric Bernon
      * api_msg.c: Fix bug #20318: api_msg "recv" callbacks don't call pbuf_free in
        all error cases.

      2007-07-13 Frédéric Bernon
      * api_msg.c: Fix bug #20315: possible memory leak problem if tcp_listen failed,
        because current code doesn't follow rawapi.txt documentation.

      2007-07-13 Kieran Mansley
      * src/core/tcp_in.c Apply patch#5741 from Oleg Tyshev to fix bug in
        out of sequence processing of received packets

      2007-07-03 Simon Goldschmidt
      * nearly-all-files: Added assertions where PBUF_RAM pbufs are used and an
        assumption is made that this pbuf is in one piece (i.e. not chained). These
        assumptions clash with the possibility of converting to fully pool-based
        pbuf implementations, where PBUF_RAM pbufs might be chained.

      2007-07-03 Simon Goldschmidt
      * api.h, api_lib.c, api_msg.c: Final fix for bug #20021 and some other problems
        when closing tcp netconns: removed conn->sem, less context switches when
        closing, both netconn_close and netconn_delete should safely close tcp
        connections.

      2007-07-02 Simon Goldschmidt
      * ipv4/ip.h, ipv6/ip.h, opt.h, netif.h, etharp.h, ipv4/ip.c, netif.c, raw.c,
        tcp_out.c, udp.c, etharp.c: Added option LWIP_NETIF_HWADDRHINT (default=off)
        to cache ARP table indices with each pcb instead of single-entry cache for
        the complete stack.

      2007-07-02 Simon Goldschmidt
      * tcp.h, tcp.c, tcp_in.c, tcp_out.c: Added some ASSERTS and casts to prevent
        warnings when assigning to smaller types.

      2007-06-28 Simon Goldschmidt
      * tcp_out.c: Added check to prevent tcp_pcb->snd_queuelen from overflowing.

      2007-06-28 Simon Goldschmidt
      * tcp.h: Fixed bug #20287: Fixed nagle algorithm (sending was done too early if
        a segment contained chained pbufs)

      2007-06-28 Frédéric Bernon
      * autoip.c: replace most of rand() calls by a macro LWIP_AUTOIP_RAND which compute
        a "pseudo-random" value based on netif's MAC and some autoip fields. It's always
        possible to define this macro in your own lwipopts.h to always use C library's
        rand(). Note that autoip_create_rand_addr doesn't use this macro.

      2007-06-28 Frédéric Bernon
      * netifapi.h, netifapi.c, tcpip.h, tcpip.c: Update code to handle the option
        LWIP_TCPIP_CORE_LOCKING, and do some changes to be coherent with last modifications
        in api_lib/api_msg (use pointers and not type with table, etc...)

      2007-06-26 Simon Goldschmidt
      * udp.h: Fixed bug #20259: struct udp_hdr was lacking the packin defines.

      2007-06-25 Simon Goldschmidt
      * udp.c: Fixed bug #20253: icmp_dest_unreach was called with a wrong p->payload
        for udp packets with no matching pcb.

      2007-06-25 Simon Goldschmidt
      * udp.c: Fixed bug #20220: UDP PCB search in udp_input(): a non-local match
        could get udp input packets if the remote side matched.

      2007-06-13 Simon Goldschmidt
      * netif.c: Fixed bug #20180 (TCP pcbs listening on IP_ADDR_ANY could get
        changed in netif_set_ipaddr if previous netif->ip_addr.addr was 0.

      2007-06-13 Simon Goldschmidt
      * api_msg.c: pcb_new sets conn->err if protocol is not implemented
        -> netconn_new_..() does not allocate a new connection for unsupported
        protocols.

      2007-06-13 Frédéric Bernon, Simon Goldschmidt
      * api_lib.c: change return expression in netconn_addr and netconn_peer, because
        conn->err was reset to ERR_OK without any reasons (and error was lost)...

      2007-06-13 Frédéric Bernon, Matthias Weisser
      * opt.h, mem.h, mem.c, memp.c, pbuf.c, ip_frag.c, vj.c: Fix bug #20162. Rename
        MEM_ALIGN in LWIP_MEM_ALIGN and MEM_ALIGN_SIZE in LWIP_MEM_ALIGN_SIZE to avoid
        some macro names collision with some OS macros.

      2007-06-11 Simon Goldschmidt
      * udp.c: UDP Lite: corrected the use of chksum_len (based on RFC3828: if it's 0,
        create checksum over the complete packet. On RX, if it's < 8 (and not 0),
        discard the packet. Also removed the duplicate 'udphdr->chksum = 0' for both
        UDP & UDP Lite.

      2007-06-11 Srinivas Gollakota & Oleg Tyshev
      * tcp_out.c: Fix for bug #20075 : "A problem with keep-alive timer and TCP flags"
        where TCP flags wasn't initialized in tcp_keepalive.

      2007-06-03 Simon Goldschmidt
      * udp.c: udp_input(): Input pbuf was not freed if pcb had no recv function
        registered, p->payload was modified without modifying p->len if sending
        icmp_dest_unreach() (had no negative effect but was definitively wrong).

      2007-06-03 Simon Goldschmidt
      * icmp.c: Corrected bug #19937: For responding to an icmp echo request, icmp
        re-used the input pbuf even if that didn't have enough space to include the
        link headers. Now the space is tested and a new pbuf is allocated for the
        echo response packet if the echo request pbuf isn't big enough.

      2007-06-01 Simon Goldschmidt
      * sockets.c: Checked in patch #5914: Moved sockopt processing into tcpip_thread.

      2007-05-23 Frédéric Bernon
      * api_lib.c, sockets.c: Fixed bug #5958 for netconn_listen (acceptmbox only
        allocated by do_listen if success) and netconn_accept errors handling. In
        most of api_lib functions, we replace some errors checkings like "if (conn==NULL)"
        by ASSERT, except for netconn_delete.

      2007-05-23 Frédéric Bernon
      * api_lib.c: Fixed bug #5957 "Safe-thread problem inside netconn_recv" to return
        an error code if it's impossible to fetch a pbuf on a TCP connection (and not
        directly close the recvmbox).

      2007-05-22 Simon Goldschmidt
      * tcp.c: Fixed bug #1895 (tcp_bind not correct) by introducing a list of
        bound but unconnected (and non-listening) tcp_pcbs.

      2007-05-22 Frédéric Bernon
      * sys.h, sys.c, api_lib.c, tcpip.c: remove sys_mbox_fetch_timeout() (was only
        used for LWIP_SO_RCVTIMEO option) and use sys_arch_mbox_fetch() instead of
        sys_mbox_fetch() in api files. Now, users SHOULD NOT use internal lwIP features
        like "sys_timeout" in their application threads.

      2007-05-22 Frédéric Bernon
      * api.h, api_lib.c, api_msg.h, api_msg.c: change the struct api_msg_msg to see
        which parameters are used by which do_xxx function, and to avoid "misusing"
        parameters (patch #5938).

      2007-05-22 Simon Goldschmidt
      * api_lib.c, api_msg.c, raw.c, api.h, api_msg.h, raw.h: Included patch #5938:
        changed raw_pcb.protocol from u16_t to u8_t since for IPv4 and IPv6, proto
        is only 8 bits wide. This affects the api, as there, the protocol was
        u16_t, too.

      2007-05-18 Simon Goldschmidt
      * memp.c: addition to patch #5913: smaller pointer was returned but
        memp_memory was the same size -> did not save memory.

      2007-05-16 Simon Goldschmidt
      * loopif.c, slipif.c: Fix bug #19729: free pbuf if netif->input() returns
        != ERR_OK.

      2007-05-16 Simon Goldschmidt
      * api_msg.c, udp.c: If a udp_pcb has a local_ip set, check if it is the same
        as the one of the netif used for sending to prevent sending from old
        addresses after a netif address gets changed (partly fixes bug #3168).

      2007-05-16 Frédéric Bernon
      * tcpip.c, igmp.h, igmp.c: Fixed bug "#19800 : IGMP: igmp_tick() will not work
        with NO_SYS=1". Note that igmp_init is always in tcpip_thread (and not in
        tcpip_init) because we have to be sure that network interfaces are already
        added (mac filter is updated only in igmp_init for the moment).

      2007-05-16 Simon Goldschmidt
      * mem.c, memp.c: Removed semaphores from memp, changed sys_sem_wait calls
        into sys_arch_sem_wait calls to prevent timers from running while waiting
        for the heap. This fixes bug #19167.

      2007-05-13 Simon Goldschmidt
      * tcp.h, sockets.h, sockets.c: Fixed bug from patch #5865 by moving the defines
        for socket options (lwip_set/-getsockopt) used with level IPPROTO_TCP from
        tcp.h to sockets.h.

      2007-05-07 Simon Goldschmidt
      * mem.c: Another attempt to fix bug #17922.

      2007-05-04 Simon Goldschmidt
      * pbuf.c, pbuf.h, etharp.c: Further update to ARP queueing: Changed pbuf_copy()
        implementation so that it can be reused (don't allocate the target
        pbuf inside pbuf_copy()).

      2007-05-04 Simon Goldschmidt
      * memp.c: checked in patch #5913: in memp_malloc() we can return memp as mem
        to save a little RAM (next pointer of memp is not used while not in pool).

      2007-05-03 "maq"
      * sockets.c: Fix ioctl FIONREAD when some data remains from last recv.
        (patch #3574).

      2007-04-23 Simon Goldschmidt
      * loopif.c, loopif.h, opt.h, src/netif/FILES: fix bug #2595: "loopif results
        in NULL reference for incoming TCP packets". Loopif has to be configured
        (using LWIP_LOOPIF_MULTITHREADING) to directly call netif->input()
        (multithreading environments, e.g. netif->input() = tcpip_input()) or
        putting packets on a list that is fed to the stack by calling loopif_poll()
        (single-thread / NO_SYS / polling environment where e.g.
        netif->input() = ip_input).

      2007-04-17 Jonathan Larmour
      * pbuf.c: Use s32_t in pbuf_realloc(), as an s16_t can't reliably hold
        the difference between two u16_t's.
      * sockets.h: FD_SETSIZE needs to match number of sockets, which is
        MEMP_NUM_NETCONN in sockets.c right now.

      2007-04-12 Jonathan Larmour
      * icmp.c: Reset IP header TTL in ICMP ECHO responses (bug #19580).

      2007-04-12 Kieran Mansley
      * tcp.c, tcp_in.c, tcp_out.c, tcp.h: Modify way the retransmission
        timer is reset to fix bug#19434, with help from Oleg Tyshev.

      2007-04-11 Simon Goldschmidt
      * etharp.c, pbuf.c, pbuf.h: 3rd fix for bug #11400 (arp-queuing): More pbufs than
        previously thought need to be copied (everything but PBUF_ROM!). Cleaned up
        pbuf.c: removed functions no needed any more (by etharp).

      2007-04-11 Kieran Mansley
      * inet.c, ip_addr.h, sockets.h, sys.h, tcp.h: Apply patch #5745: Fix
        "Constant is long" warnings with 16bit compilers.  Contributed by
        avatar@mmlab.cse.yzu.edu.tw

      2007-04-05 Frédéric Bernon, Jonathan Larmour
      * api_msg.c: Fix bug #16830: "err_tcp() posts to connection mailbox when no pend on
        the mailbox is active". Now, the post is only done during a connect, and do_send,
        do_write and do_join_leave_group don't do anything if a previous error was signaled.

      2007-04-03 Frédéric Bernon
      * ip.c: Don't set the IP_DF ("Don't fragment") flag in the IP header in IP output
        packets. See patch #5834.

      2007-03-30 Frédéric Bernon
      * api_msg.c: add a "pcb_new" helper function to avoid redundant code, and to add
        missing  pcb allocations checking (in do_bind, and for each raw_new). Fix style.

      2007-03-30 Frédéric Bernon
      * most of files: prefix all debug.h define with "LWIP_" to avoid any conflict with
        others environment defines (these were too "generic").

      2007-03-28 Frédéric Bernon
      * api.h, api_lib.c, sockets.c: netbuf_ref doesn't check its internal pbuf_alloc call
        result and can cause a crash. lwip_send now check netbuf_ref result.

      2007-03-28 Simon Goldschmidt
      * sockets.c Remove "#include <errno.h>" from sockets.c to avoid multiple
        definition of macros (in errno.h and lwip/arch.h) if LWIP_PROVIDE_ERRNO is
        defined. This is the way it should have been already (looking at
        doc/sys_arch.txt)

      2007-03-28 Kieran Mansley
      * opt.h Change default PBUF_POOL_BUFSIZE (again) to accomodate default MSS +
        IP and TCP headers *and* physical link headers

      2007-03-26 Frédéric Bernon (based on patch from Dmitry Potapov)
      * api_lib.c: patch for netconn_write(), fixes a possible race condition which cause
        to send some garbage. It is not a definitive solution, but the patch does solve
        the problem for most cases.

      2007-03-22 Frédéric Bernon
      * api_msg.h, api_msg.c: Remove obsolete API_MSG_ACCEPT and do_accept (never used).

      2007-03-22 Frédéric Bernon
      * api_lib.c: somes resources couldn't be freed if there was errors during
        netconn_new_with_proto_and_callback.

      2007-03-22 Frédéric Bernon
      * ethernetif.c: update netif->input calls to check return value. In older ports,
        it's a good idea to upgrade them, even if before, there could be another problem
        (access to an uninitialized mailbox).

      2007-03-21 Simon Goldschmidt
      * sockets.c: fixed bug #5067 (essentialy a signed/unsigned warning fixed
        by casting to unsigned).

      2007-03-21 Frédéric Bernon
      * api_lib.c, api_msg.c, tcpip.c: integrate sys_mbox_fetch(conn->mbox, NULL) calls from
        api_lib.c to tcpip.c's tcpip_apimsg(). Now, use a local variable and not a
        dynamic one from memp to send tcpip_msg to tcpip_thread in a synchrone call.
        Free tcpip_msg from tcpip_apimsg is not done in tcpip_thread. This give a
        faster and more reliable communication between api_lib and tcpip.

      2007-03-21 Frédéric Bernon
      * opt.h: Add LWIP_NETIF_CALLBACK (to avoid compiler warning) and set it to 0.

      2007-03-21 Frédéric Bernon
      * api_msg.c, igmp.c, igmp.h: Fix C++ style comments

      2007-03-21 Kieran Mansley
      * opt.h Change default PBUF_POOL_BUFSIZE to accomodate default MSS +
        IP and TCP headers

      2007-03-21 Kieran Mansley
      * Fix all uses of pbuf_header to check the return value.  In some
        cases just assert if it fails as I'm not sure how to fix them, but
        this is no worse than before when they would carry on regardless
        of the failure.

      2007-03-21 Kieran Mansley
      * sockets.c, igmp.c, igmp.h, memp.h: Fix C++ style comments and
        comment out missing header include in icmp.c

      2007-03-20 Frédéric Bernon
      * memp.h, stats.c: Fix stats_display function where memp_names table wasn't
        synchronized with memp.h.

      2007-03-20 Frédéric Bernon
      * tcpip.c: Initialize tcpip's mbox, and verify if initialized in tcpip_input,
        tcpip_ethinput, tcpip_callback, tcpip_apimsg, to fix a init problem with
        network interfaces. Also fix a compiler warning.

      2007-03-20 Kieran Mansley
      * udp.c: Only try and use pbuf_header() to make space for headers if
        not a ROM or REF pbuf.

      2007-03-19 Frédéric Bernon
      * api_msg.h, api_msg.c, tcpip.h, tcpip.c: Add return types to tcpip_apimsg()
        and api_msg_post().

      2007-03-19 Frédéric Bernon
      * Remove unimplemented "memp_realloc" function from memp.h.

      2007-03-11 Simon Goldschmidt
      * pbuf.c: checked in patch #5796: pbuf_alloc: len field claculation caused
        memory corruption.

      2007-03-11 Simon Goldschmidt (based on patch from Dmitry Potapov)
      * api_lib.c, sockets.c, api.h, api_msg.h, sockets.h: Fixed bug #19251
        (missing `const' qualifier in socket functions), to get more compatible to
        standard POSIX sockets.

      2007-03-11 Frédéric Bernon (based on patch from Dmitry Potapov)
      * sockets.c: Add asserts inside bind, connect and sendto to check input
        parameters. Remove excessive set_errno() calls after get_socket(), because
        errno is set inside of get_socket(). Move last sock_set_errno() inside
        lwip_close.

      2007-03-09 Simon Goldschmidt
      * memp.c: Fixed bug #11400: New etharp queueing introduced bug: memp_memory
        was allocated too small.

      2007-03-06 Simon Goldschmidt
      * tcpip.c: Initialize dhcp timers in tcpip_thread (if LWIP_DHCP) to protect
        the stack from concurrent access.

      2007-03-06 Frédéric Bernon, Dmitry Potapov
      * tcpip.c, ip_frag.c, ethernetif.c: Fix some build problems, and a redundancy
        call to "lwip_stats.link.recv++;" in low_level_input() & ethernetif_input().

      2007-03-06 Simon Goldschmidt
      * ip_frag.c, ip_frag.h: Reduce code size: don't include code in those files
        if IP_FRAG == 0 and IP_REASSEMBLY == 0

      2007-03-06 Frédéric Bernon, Simon Goldschmidt
      * opt.h, ip_frag.h, tcpip.h, tcpip.c, ethernetif.c: add new configuration
        option named ETHARP_TCPIP_ETHINPUT, which enable the new tcpip_ethinput.
        Allow to do ARP processing for incoming packets inside tcpip_thread
        (protecting ARP layer against concurrent access). You can also disable
        old code using tcp_input with new define ETHARP_TCPIP_INPUT set to 0.
        Older ports have to use tcpip_ethinput.

      2007-03-06 Simon Goldschmidt (based on patch from Dmitry Potapov)
      * err.h, err.c: fixed compiler warning "initialization dircards qualifiers
        from pointer target type"

      2007-03-05 Frédéric Bernon
      * opt.h, sockets.h: add new configuration options (LWIP_POSIX_SOCKETS_IO_NAMES,
        ETHARP_TRUST_IP_MAC, review SO_REUSE)

      2007-03-04 Frédéric Bernon
      * api_msg.c: Remove some compiler warnings : parameter "pcb" was never
        referenced.

      2007-03-04 Frédéric Bernon
      * api_lib.c: Fix "[patch #5764] api_lib.c cleanup: after patch #5687" (from
        Dmitry Potapov).
        The api_msg struct stay on the stack (not moved to netconn struct).

      2007-03-04 Simon Goldschmidt (based on patch from Dmitry Potapov)
      * pbuf.c: Fix BUG#19168 - pbuf_free can cause deadlock (if
        SYS_LIGHTWEIGHT_PROT=1 & freeing PBUF_RAM when mem_sem is not available)
        Also fixed cast warning in pbuf_alloc()

      2007-03-04 Simon Goldschmidt
      * etharp.c, etharp.h, memp.c, memp.h, opt.h: Fix BUG#11400 - don't corrupt
        existing pbuf chain when enqueuing multiple pbufs to a pending ARP request

      2007-03-03 Frédéric Bernon
      * udp.c: remove obsolete line "static struct udp_pcb *pcb_cache = NULL;"
        It is static, and never used in udp.c except udp_init().

      2007-03-02 Simon Goldschmidt
      * tcpip.c: Moved call to ip_init(), udp_init() and tcp_init() from
        tcpip_thread() to tcpip_init(). This way, raw API connections can be
        initialized before tcpip_thread is running (e.g. before OS is started)

      2007-03-02 Frédéric Bernon
      * rawapi.txt: Fix documentation mismatch with etharp.h about etharp_tmr's call
        interval.

      2007-02-28 Kieran Mansley
      * pbuf.c: Fix BUG#17645 - ensure pbuf payload pointer is not moved
        outside the region of the pbuf by pbuf_header()

      2007-02-28 Kieran Mansley
      * sockets.c: Fix BUG#19161 - ensure milliseconds timeout is non-zero
        when supplied timeout is also non-zero

    (STABLE-1.2.0)

      2006-12-05 Leon Woestenberg
      * CHANGELOG: Mention STABLE-1.2.0 release.

      ++ New features:

      2006-12-01 Christiaan Simons
      * mem.h, opt.h: Added MEM_LIBC_MALLOC option.
        Note this is a workaround. Currently I have no other options left.

      2006-10-26 Christiaan Simons (accepted patch by Jonathan Larmour)
      * ipv4/ip_frag.c: rename MAX_MTU to IP_FRAG_MAX_MTU and move define
        to include/lwip/opt.h.
      * ipv4/lwip/ip_frag.h: Remove unused IP_REASS_INTERVAL.
        Move IP_REASS_MAXAGE and IP_REASS_BUFSIZE to include/lwip/opt.h.
      * opt.h: Add above new options.

      2006-08-18 Christiaan Simons
      * tcp_{in,out}.c: added SNMP counters.
      * ipv4/ip.c: added SNMP counters.
      * ipv4/ip_frag.c: added SNMP counters.

      2006-08-08 Christiaan Simons
      * etharp.{c,h}: added etharp_find_addr() to read
        (stable) ethernet/IP address pair from ARP table

      2006-07-14 Christiaan Simons
      * mib_structs.c: added
      * include/lwip/snmp_structs.h: added
      * netif.{c,h}, netif/ethernetif.c: added SNMP statistics to netif struct

      2006-07-06 Christiaan Simons
      * snmp/asn1_{enc,dec}.c added
      * snmp/mib2.c added
      * snmp/msg_{in,out}.c added
      * include/lwip/snmp_asn1.h added
      * include/lwip/snmp_msg.h added
      * doc/snmp_agent.txt added

      2006-03-29 Christiaan Simons
      * inet.c, inet.h: Added platform byteswap support.
        Added LWIP_PLATFORM_BYTESWAP define (defaults to 0) and
        optional LWIP_PLATFORM_HTONS(), LWIP_PLATFORM_HTONL() macros.

      ++ Bug fixes:

      2006-11-30 Christiaan Simons
      * dhcp.c: Fixed false triggers of request_timeout.

      2006-11-28 Christiaan Simons
      * netif.c: In netif_add() fixed missing clear of ip_addr, netmask, gw and flags.

      2006-10-11 Christiaan Simons
      * api_lib.c etharp.c, ip.c, memp.c, stats.c, sys.{c,h} tcp.h:
        Partially accepted patch #5449 for ANSI C compatibility / build fixes.
      * ipv4/lwip/ip.h ipv6/lwip/ip.h: Corrected UDP-Lite protocol
        identifier from 170 to 136 (bug #17574).

      2006-10-10 Christiaan Simons
      * api_msg.c: Fixed Nagle algorithm as reported by Bob Grice.

      2006-08-17 Christiaan Simons
      * udp.c: Fixed bug #17200, added check for broadcast
        destinations for PCBs bound to a unicast address.

      2006-08-07 Christiaan Simons
      * api_msg.c: Flushing TCP output in do_close() (bug #15926).

      2006-06-27 Christiaan Simons
      * api_msg.c: Applied patch for cold case (bug #11135).
        In accept_function() ensure newconn->callback is always initialized.

      2006-06-15 Christiaan Simons
      * mem.h: added MEM_SIZE_F alias to fix an ancient cold case (bug #1748),
        facilitate printing of mem_size_t and u16_t statistics.

      2006-06-14 Christiaan Simons
      * api_msg.c: Applied patch #5146 to handle allocation failures
        in accept() by Kevin Lawson.

      2006-05-26 Christiaan Simons
      * api_lib.c: Removed conn->sem creation and destruction
        from netconn_write() and added sys_sem_new to netconn_new_*.

    (STABLE-1_1_1)

      2006-03-03  Christiaan Simons
      * ipv4/ip_frag.c: Added bound-checking assertions on ip_reassbitmap
        access and added pbuf_alloc() return value checks.

      2006-01-01  Leon Woestenberg <leon.woestenberg@gmx.net>
      * tcp_{in,out}.c, tcp_out.c: Removed 'even sndbuf' fix in TCP, which is
        now handled by the checksum routine properly.

      2006-02-27  Leon Woestenberg <leon.woestenberg@gmx.net>
       * pbuf.c: Fix alignment; pbuf_init() would not work unless
         pbuf_pool_memory[] was properly aligned. (Patch by Curt McDowell.)

      2005-12-20  Leon Woestenberg <leon.woestenberg@gmx.net>
      * tcp.c: Remove PCBs which stay in LAST_ACK state too long. Patch
        submitted by Mitrani Hiroshi.

      2005-12-15  Christiaan Simons
      * inet.c: Disabled the added summing routine to preserve code space.

      2005-12-14  Leon Woestenberg <leon.woestenberg@gmx.net>
      * tcp_in.c: Duplicate FIN ACK race condition fix by Kelvin Lawson.
        Added Curt McDowell's optimized checksumming routine for future
        inclusion. Need to create test case for unaliged, aligned, odd,
        even length combination of cases on various endianess machines.

      2005-12-09  Christiaan Simons
      * inet.c: Rewrote standard checksum routine in proper portable C.

      2005-11-25  Christiaan Simons
      * udp.c tcp.c: Removed SO_REUSE hack. Should reside in socket code only.
      * *.c: introduced cc.h LWIP_DEBUG formatters matching the u16_t, s16_t,
        u32_t, s32_t typedefs. This solves most debug word-length assumes.

      2005-07-17 Leon Woestenberg <leon.woestenberg@gmx.net>
      * inet.c: Fixed unaligned 16-bit access in the standard checksum
        routine by Peter Jolasson.
      * slipif.c: Fixed implementation assumption of single-pbuf datagrams.

      2005-02-04 Leon Woestenberg <leon.woestenberg@gmx.net>
      * tcp_out.c: Fixed uninitialized 'queue' referenced in memerr branch.
      * tcp_{out|in}.c: Applied patch fixing unaligned access.

      2005-01-04 Leon Woestenberg <leon.woestenberg@gmx.net>
      * pbuf.c: Fixed missing semicolon after LWIP_DEBUG statement.

      2005-01-03 Leon Woestenberg <leon.woestenberg@gmx.net>
      * udp.c: UDP pcb->recv() was called even when it was NULL.

    (STABLE-1_1_0)

      2004-12-28 Leon Woestenberg <leon.woestenberg@gmx.net>
      * etharp.*: Disabled multiple packets on the ARP queue.
        This clashes with TCP queueing.

      2004-11-28 Leon Woestenberg <leon.woestenberg@gmx.net>
      * etharp.*: Fixed race condition from ARP request to ARP timeout.
        Halved the ARP period, doubled the period counts.
        ETHARP_MAX_PENDING now should be at least 2. This prevents
        the counter from reaching 0 right away (which would allow
        too little time for ARP responses to be received).

      2004-11-25 Leon Woestenberg <leon.woestenberg@gmx.net>
      * dhcp.c: Decline messages were not multicast but unicast.
      * etharp.c: ETHARP_CREATE is renamed to ETHARP_TRY_HARD.
        Do not try hard to insert arbitrary packet's source address,
        etharp_ip_input() now calls etharp_update() without ETHARP_TRY_HARD.
        etharp_query() now always DOES call ETHARP_TRY_HARD so that users
        querying an address will see it appear in the cache (DHCP could
        suffer from this when a server invalidly gave an in-use address.)
      * ipv4/ip_addr.h: Renamed ip_addr_maskcmp() to _netcmp() as we are
        comparing network addresses (identifiers), not the network masks
        themselves.
      * ipv4/ip_addr.c: ip_addr_isbroadcast() now checks that the given
        IP address actually belongs to the network of the given interface.

      2004-11-24 Kieran Mansley <kjm25@cam.ac.uk>
      * tcp.c: Increment pcb->snd_buf when ACK is received in SYN_SENT state.

    (STABLE-1_1_0-RC1)

      2004-10-16 Kieran Mansley <kjm25@cam.ac.uk>
      * tcp.c: Add code to tcp_recved() to send an ACK (window update) immediately,
        even if one is already pending, if the rcv_wnd is above a threshold
        (currently TCP_WND/2). This avoids waiting for a timer to expire to send a
        delayed ACK in order to open the window if the stack is only receiving data.

      2004-09-12 Kieran Mansley <kjm25@cam.ac.uk>
      * tcp*.*: Retransmit time-out handling improvement by Sam Jansen.

      2004-08-20 Tony Mountifield <tony@softins.co.uk>
      * etharp.c: Make sure the first pbuf queued on an ARP entry
        is properly ref counted.

      2004-07-27 Tony Mountifield <tony@softins.co.uk>
      * debug.h: Added (int) cast in LWIP_DEBUGF() to avoid compiler
        warnings about comparison.
      * pbuf.c: Stopped compiler complaining of empty if statement
        when LWIP_DEBUGF() empty.  Closed an unclosed comment.
      * tcp.c: Stopped compiler complaining of empty if statement
        when LWIP_DEBUGF() empty.
      * ip.h Corrected IPH_TOS() macro: returns a byte, so doesn't need htons().
      * inet.c: Added a couple of casts to quiet the compiler.
        No need to test isascii(c) before isdigit(c) or isxdigit(c).

      2004-07-22 Tony Mountifield <tony@softins.co.uk>
      * inet.c: Made data types consistent in inet_ntoa().
        Added casts for return values of checksum routines, to pacify compiler.
      * ip_frag.c, tcp_out.c, sockets.c, pbuf.c
        Small corrections to some debugging statements, to pacify compiler.

      2004-07-21 Tony Mountifield <tony@softins.co.uk>
      * etharp.c: Removed spurious semicolon and added missing end-of-comment.
      * ethernetif.c Updated low_level_output() to match prototype for
        netif->linkoutput and changed low_level_input() similarly for consistency.
      * api_msg.c: Changed recv_raw() from int to u8_t, to match prototype
        of raw_recv() in raw.h and so avoid compiler error.
      * sockets.c: Added trivial (int) cast to keep compiler happier.
      * ip.c, netif.c Changed debug statements to use the tidier ip4_addrN() macros.

    (STABLE-1_0_0)

      ++ Changes:

      2004-07-05 Leon Woestenberg <leon.woestenberg@gmx.net>
      * sockets.*: Restructured LWIP_PRIVATE_TIMEVAL. Make sure
        your cc.h file defines this either 1 or 0. If non-defined,
        defaults to 1.
      * .c: Added <string.h> and <errno.h> includes where used.
      * etharp.c: Made some array indices unsigned.

      2004-06-27 Leon Woestenberg <leon.woestenberg@gmx.net>
      * netif.*: Added netif_set_up()/down().
      * dhcp.c: Changes to restart program flow.

      2004-05-07 Leon Woestenberg <leon.woestenberg@gmx.net>
      * etharp.c: In find_entry(), instead of a list traversal per candidate, do a
        single-pass lookup for different candidates. Should exploit locality.

      2004-04-29 Leon Woestenberg <leon.woestenberg@gmx.net>
      * tcp*.c: Cleaned up source comment documentation for Doxygen processing.
      * opt.h: ETHARP_ALWAYS_INSERT option removed to comply with ARP RFC.
      * etharp.c: update_arp_entry() only adds new ARP entries when adviced to by
        the caller. This deprecates the ETHARP_ALWAYS_INSERT overrule option.

      ++ Bug fixes:

      2004-04-27 Leon Woestenberg <leon.woestenberg@gmx.net>
      * etharp.c: Applied patch of bug #8708 by Toni Mountifield with a solution
        suggested by Timmy Brolin. Fix for 32-bit processors that cannot access
        non-aligned 32-bit words, such as soms 32-bit TCP/IP header fields. Fix
        is to prefix the 14-bit Ethernet headers with two padding bytes.

      2004-04-23 Leon Woestenberg <leon.woestenberg@gmx.net>
      * ip_addr.c: Fix in the ip_addr_isbroadcast() check.
      * etharp.c: Fixed the case where the packet that initiates the ARP request
        is not queued, and gets lost. Fixed the case where the packets destination
        address is already known; we now always queue the packet and perform an ARP
        request.

    (STABLE-0_7_0)

      ++ Bug fixes:

      * Fixed TCP bug for SYN_SENT to ESTABLISHED state transition.
      * Fixed TCP bug in dequeueing of FIN from out of order segment queue.
      * Fixed two possible NULL references in rare cases.

    (STABLE-0_6_6)

      ++ Bug fixes:

      * Fixed DHCP which did not include the IP address in DECLINE messages.

      ++ Changes:

      * etharp.c has been hauled over a bit.

    (STABLE-0_6_5)

      ++ Bug fixes:

      * Fixed TCP bug induced by bad window resizing with unidirectional TCP traffic.
      * Packets sent from ARP queue had invalid source hardware address.

      ++ Changes:

      * Pass-by ARP requests do now update the cache.

      ++ New features:

      * No longer dependent on ctype.h.
      * New socket options.
      * Raw IP pcb support.

    (STABLE-0_6_4)

      ++ Bug fixes:

      * Some debug formatters and casts fixed.
      * Numereous fixes in PPP.

      ++ Changes:

      * DEBUGF now is LWIP_DEBUGF
      * pbuf_dechain() has been re-enabled.
      * Mentioned the changed use of CVS branches in README.

    (STABLE-0_6_3)

      ++ Bug fixes:

      * Fixed pool pbuf memory leak in pbuf_alloc().
        Occured if not enough PBUF_POOL pbufs for a packet pbuf chain.
        Reported by Savin Zlobec.

      * PBUF_POOL chains had their tot_len field not set for non-first
        pbufs. Fixed in pbuf_alloc().

      ++ New features:

      * Added PPP stack contributed by Marc Boucher

      ++ Changes:

      * Now drops short packets for ICMP/UDP/TCP protocols. More robust.

      * ARP queueuing now queues the latest packet instead of the first.
        This is the RFC recommended behaviour, but can be overridden in
        lwipopts.h.

    (0.6.2)

      ++ Bugfixes:

      * TCP has been fixed to deal with the new use of the pbuf->ref
        counter.

      * DHCP dhcp_inform() crash bug fixed.

      ++ Changes:

      * Removed pbuf_pool_free_cache and pbuf_pool_alloc_cache. Also removed
        pbuf_refresh(). This has sped up pbuf pool operations considerably.
        Implemented by David Haas.

    (0.6.1)

      ++ New features:

      * The packet buffer implementation has been enhanced to support
        zero-copy and copy-on-demand for packet buffers which have their
        payloads in application-managed memory.
        Implemented by David Haas.

        Use PBUF_REF to make a pbuf refer to RAM. lwIP will use zero-copy
        if an outgoing packet can be directly sent on the link, or perform
        a copy-on-demand when necessary.

        The application can safely assume the packet is sent, and the RAM
        is available to the application directly after calling udp_send()
        or similar function.

      ++ Bugfixes:

      * ARP_QUEUEING should now correctly work for all cases, including
        PBUF_REF.
        Implemented by Leon Woestenberg.

      ++ Changes:

      * IP_ADDR_ANY is no longer a NULL pointer. Instead, it is a pointer
        to a '0.0.0.0' IP address.

      * The packet buffer implementation is changed. The pbuf->ref counter
        meaning has changed, and several pbuf functions have been
        adapted accordingly.

      * netif drivers have to be changed to set the hardware address length field
        that must be initialized correctly by the driver (hint: 6 for Ethernet MAC).
        See the contrib/ports/c16x cs8900 driver as a driver example.

      * netif's have a dhcp field that must be initialized to NULL by the driver.
        See the contrib/ports/c16x cs8900 driver as a driver example.

    (0.5.x) This file has been unmaintained up to 0.6.1. All changes are
      logged in CVS but have not been explained here.

    (0.5.3) Changes since version 0.5.2

      ++ Bugfixes:

      * memp_malloc(MEMP_API_MSG) could fail with multiple application
        threads because it wasn't protected by semaphores.

      ++ Other changes:

      * struct ip_addr now packed.

      * The name of the time variable in arp.c has been changed to ctime
        to avoid conflicts with the time() function.

    (0.5.2) Changes since version 0.5.1

      ++ New features:

      * A new TCP function, tcp_tmr(), now handles both TCP timers.

      ++ Bugfixes:

      * A bug in tcp_parseopt() could cause the stack to hang because of a
        malformed TCP option.

      * The address of new connections in the accept() function in the BSD
        socket library was not handled correctly.

      * pbuf_dechain() did not update the ->tot_len field of the tail.

      * Aborted TCP connections were not handled correctly in all
        situations.

      ++ Other changes:

      * All protocol header structs are now packed.

      * The ->len field in the tcp_seg structure now counts the actual
        amount of data, and does not add one for SYN and FIN segments.

    (0.5.1) Changes since version 0.5.0

      ++ New features:

      * Possible to run as a user process under Linux.

      * Preliminary support for cross platform packed structs.

      * ARP timer now implemented.

      ++ Bugfixes:

      * TCP output queue length was badly initialized when opening
        connections.

      * TCP delayed ACKs were not sent correctly.

      * Explicit initialization of BSS segment variables.

      * read() in BSD socket library could drop data.

      * Problems with memory alignment.

      * Situations when all TCP buffers were used could lead to
        starvation.

      * TCP MSS option wasn't parsed correctly.

      * Problems with UDP checksum calculation.

      * IP multicast address tests had endianess problems.

      * ARP requests had wrong destination hardware address.

      ++ Other changes:

      * struct eth_addr changed from u16_t[3] array to u8_t[6].

      * A ->linkoutput() member was added to struct netif.

      * TCP and UDP ->dest_* struct members where changed to ->remote_*.

      * ntoh* macros are now null definitions for big endian CPUs.

    (0.5.0) Changes since version 0.4.2

      ++ New features:

      * Redesigned operating system emulation layer to make porting easier.

      * Better control over TCP output buffers.

      * Documenation added.

      ++ Bugfixes:

      * Locking issues in buffer management.

      * Bugfixes in the sequential API.

      * IP forwarding could cause memory leakage. This has been fixed.

      ++ Other changes:

      * Directory structure somewhat changed; the core/ tree has been
        collapsed.

    (0.4.2) Changes since version 0.4.1

      ++ New features:

      * Experimental ARP implementation added.

      * Skeleton Ethernet driver added.

      * Experimental BSD socket API library added.

      ++ Bugfixes:

      * In very intense situations, memory leakage could occur. This has
        been fixed.

      ++ Other changes:

      * Variables named "data" and "code" have been renamed in order to
        avoid name conflicts in certain compilers.

      * Variable++ have in appliciable cases been translated to ++variable
        since some compilers generate better code in the latter case.

    (0.4.1) Changes since version 0.4

      ++ New features:

      * TCP: Connection attempts time out earlier than data
        transmissions. Nagle algorithm implemented. Push flag set on the
        last segment in a burst.

      * UDP: experimental support for UDP-Lite extensions.

      ++ Bugfixes:

      * TCP: out of order segments were in some cases handled incorrectly,
        and this has now been fixed. Delayed acknowledgements was broken
        in 0.4, has now been fixed. Binding to an address that is in use
        now results in an error. Reset connections sometimes hung an
        application; this has been fixed.

      * Checksum calculation sometimes failed for chained pbufs with odd
        lengths. This has been fixed.

      * API: a lot of bug fixes in the API. The UDP API has been improved
        and tested. Error reporting and handling has been
        improved. Logical flaws and race conditions for incoming TCP
        connections has been found and removed.

      * Memory manager: alignment issues. Reallocating memory sometimes
        failed, this has been fixed.

      * Generic library: bcopy was flawed and has been fixed.

      ++ Other changes:

      * API: all datatypes has been changed from generic ones such as
        ints, to specified ones such as u16_t. Functions that return
        errors now have the correct type (err_t).

      * General: A lot of code cleaned up and debugging code removed. Many
        portability issues have been fixed.

      * The license was changed; the advertising clause was removed.

      * C64 port added.

      * Thanks: Huge thanks go to Dagan Galarneau, Horst Garnetzke, Petri
        Kosunen, Mikael Caleres, and Frits Wilmink for reporting and
        fixing bugs!

    (0.4) Changes since version 0.3.1

      * Memory management has been radically changed; instead of
        allocating memory from a shared heap, memory for objects that are
        rapidly allocated and deallocated is now kept in pools. Allocation
        and deallocation from those memory pools is very fast. The shared
        heap is still present but is used less frequently.

      * The memory, memory pool, and packet buffer subsystems now support
        4-, 2-, or 1-byte alignment.

      * "Out of memory" situations are handled in a more robust way.

      * Stack usage has been reduced.

      * Easier configuration of lwIP parameters such as memory usage,
        TTLs, statistics gathering, etc. All configuration parameters are
        now kept in a single header file "lwipopts.h".

      * The directory structure has been changed slightly so that all
        architecture specific files are kept under the src/arch
        hierarchy.

      * Error propagation has been improved, both in the protocol modules
        and in the API.

      * The code for the RTXC architecture has been implemented, tested
        and put to use.

      * Bugs have been found and corrected in the TCP, UDP, IP, API, and
        the Internet checksum modules.

      * Bugs related to porting between a 32-bit and a 16-bit architecture
        have been found and corrected.

      * The license has been changed slightly to conform more with the
        original BSD license, including the advertisement clause.

    (0.3.1) Changes since version 0.3

      * Fix of a fatal bug in the buffer management. Pbufs with allocated
        RAM never returned the RAM when the pbuf was deallocated.

      * TCP congestion control, window updates and retransmissions did not
        work correctly. This has now been fixed.

      * Bugfixes in the API.

    (0.3) Changes since version 0.2

      * New and improved directory structure. All include files are now
        kept in a dedicated include/ directory.

      * The API now has proper error handling. A new function,
        netconn_err(), now returns an error code for the connection in
        case of errors.

      * Improvements in the memory management subsystem. The system now
        keeps a pointer to the lowest free memory block. A new function,
        mem_malloc2() tries to allocate memory once, and if it fails tries
        to free some memory and retry the allocation.

      * Much testing has been done with limited memory
        configurations. lwIP now does a better job when overloaded.

      * Some bugfixes and improvements to the buffer (pbuf) subsystem.

      * Many bugfixes in the TCP code:

        - Fixed a bug in tcp_close().

        - The TCP receive window was incorrectly closed when out of
          sequence segments was received. This has been fixed.

        - Connections are now timed-out of the FIN-WAIT-2 state.

        - The initial congestion window could in some cases be too
          large. This has been fixed.

        - The retransmission queue could in some cases be screwed up. This
          has been fixed.

        - TCP RST flag now handled correctly.

        - Out of sequence data was in some cases never delivered to the
          application. This has been fixed.

        - Retransmitted segments now contain the correct acknowledgment
          number and advertised window.

        - TCP retransmission timeout backoffs are not correctly computed
          (ala BSD). After a number of retransmissions, TCP now gives up
          the connection.

      * TCP connections now are kept on three lists, one for active
        connections, one for listening connections, and one for
        connections that are in TIME-WAIT. This greatly speeds up the fast
        timeout processing for sending delayed ACKs.

      * TCP now provides proper feedback to the application when a
        connection has been successfully set up.

      * More comments have been added to the code. The code has also been
        somewhat cleaned up.

    (0.2) Initial public release.