[pes-rpp/rpp-lwip.git] / 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:

  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 #21535.

  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:

  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.