lwip/CHANGELOG

FUTURE

  * TODO: The lwIP source code makes some invalid assumptions on processor
    word-length, storage sizes and alignment. See the mailing lists for
    problems with exoteric (/DSP) architectures showing these problems.
    We still have to fix some of these issues neatly.

  * TODO: the PPP code is broken in a few ways. There are namespace
    collisions on BSD systems and many assumptions on word-length
    (sizeof(int)). In ppp.c an assumption is made on the availability of
    a thread subsystem. Either PPP needs to be moved to contrib/ports/???
    or rearranged to be more generic.

HISTORY

(CVS HEAD)

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

  ++ New features:

  2007-06-30 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * api_lib.c: Implement SO_RCVTIMEO for accept and recv on TCP
    connections, such present in patch #5959.

  2007-05-23 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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:

  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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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).

  2007-04-11 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * api_msg.h, api_msg.c: Remove obsolete API_MSG_ACCEPT and do_accept (never used).

  2007-03-22 Fr<46>d<EFBFBD>ric Bernon
  * api_lib.c: somes resources couldn't be freed if there was errors during
    netconn_new_with_proto_and_callback.

  2007-03-22 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * opt.h: Add LWIP_NETIF_CALLBACK (to avoid compiler warning) and set it to 0.

  2007-03-21 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * memp.h, stats.c: Fix stats_display function where memp_names table wasn't
    synchronized with memp.h.
  
  2007-03-20 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * api_msg.h, api_msg.c, tcpip.h, tcpip.c: Add return types to tcpip_apimsg()
    and api_msg_post().
  
  2007-03-19 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric Bernon
  * opt.h, sockets.h: add new configuration options (LWIP_POSIX_SOCKETS_IO_NAMES,
    ETHARP_TRUST_IP_MAC, review SO_REUSE)
  
  2007-03-04 Fr<46>d<EFBFBD>ric Bernon
  * api_msg.c: Remove some compiler warnings : parameter "pcb" was never
    referenced.

  2007-03-04 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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 Fr<46>d<EFBFBD>ric 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.