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Joel Cunningham c722261142 tcp: bug #50614: move unsent queue check/pcb->snd_buf update
This commit corrects what looks like an ancient incorrect organization
of the logic for processing an ACK which acks new data.  Once moved,
we can also change to using TCP_SEQ_LEQ on ackno instead of TCP_BETWEEN
because ackno has already been checked against snd_nxt

The work of checking the unsent queue and updating pcb->snd_buf (both
steps required for new data ACK) should be located under the conditional
that checks TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)

The comment following the unsent queue check/pcb->snd_buf update even
indicates "End of ACK for new data processing" when the logic is clearly
outside of this check

From what I can tell, this mis-organization isn't causing any incorrect
behavior since the unsent queue checked that ackno was between start of
segment and snd_nxt and recv_acked would be 0 during pcb->snd_buf update.
Instead this is waisted work for duplicate ACKS (can be common) and other
old ACKs
2017-03-29 16:24:54 -05:00
doc Improve documentation, add TLS stuff 2017-03-28 21:25:49 +02:00
src tcp: bug #50614: move unsent queue check/pcb->snd_buf update 2017-03-29 16:24:54 -05:00
test lwip_fcntl() returns access modes 2017-03-29 20:46:30 +02:00
.gitattributes Added .gitattributes to normalize CRLF 2014-02-07 09:36:03 +01:00
.gitignore Update .gitignore once more for fuzz test 2016-12-20 14:25:46 +01:00
CHANGELOG added nonblocking accept/recv to netconn API (task #14396) (also added netconn_recv_udp_raw_netbuf_flags() and netconn_recv_tcp_pbuf_flags() to pass socket-like flags to nonblock for one call only) 2017-03-02 20:38:11 +01:00
COPYING Re-added without vendor tag. 2002-10-20 15:13:14 +00:00
FILES update some FILES list files 2016-08-03 20:21:54 +02:00
README Update README applications sections 2016-08-14 15:39:58 +02:00
UPGRADING Fix that slipif used netif->num to pass parameters to slipif_init. 2017-02-05 12:35:42 +01:00

INTRODUCTION

lwIP is a small independent implementation of the TCP/IP protocol
suite that has been developed by Adam Dunkels at the Computer and
Networks Architectures (CNA) lab at the Swedish Institute of Computer
Science (SICS).

The focus of the lwIP TCP/IP implementation is to reduce the RAM usage
while still having a full scale TCP. This making lwIP suitable for use
in embedded systems with tens of kilobytes of free RAM and room for
around 40 kilobytes of code ROM.


FEATURES

  * IP (Internet Protocol, IPv4 and IPv6) including packet forwarding over
    multiple network interfaces
  * ICMP (Internet Control Message Protocol) for network maintenance and debugging
  * IGMP (Internet Group Management Protocol) for multicast traffic management
  * MLD (Multicast listener discovery for IPv6). Aims to be compliant with 
    RFC 2710. No support for MLDv2
  * ND (Neighbor discovery and stateless address autoconfiguration for IPv6).
    Aims to be compliant with RFC 4861 (Neighbor discovery) and RFC 4862
    (Address autoconfiguration)
  * UDP (User Datagram Protocol) including experimental UDP-lite extensions
  * TCP (Transmission Control Protocol) with congestion control, RTT estimation
    and fast recovery/fast retransmit
  * raw/native API for enhanced performance
  * Optional Berkeley-like socket API
  * DNS (Domain names resolver)


APPLICATIONS

  * HTTP server with SSI and CGI
  * SNMPv2c agent with MIB compiler (Simple Network Management Protocol)
  * SNTP (Simple network time protocol)
  * NetBIOS name service responder
  * MDNS (Multicast DNS) responder
  * iPerf server implementation


LICENSE

lwIP is freely available under a BSD license.


DEVELOPMENT

lwIP has grown into an excellent TCP/IP stack for embedded devices,
and developers using the stack often submit bug fixes, improvements,
and additions to the stack to further increase its usefulness.

Development of lwIP is hosted on Savannah, a central point for
software development, maintenance and distribution. Everyone can
help improve lwIP by use of Savannah's interface, Git and the
mailing list. A core team of developers will commit changes to the
Git source tree.

The lwIP TCP/IP stack is maintained in the 'lwip' Git module and
contributions (such as platform ports) are in the 'contrib' Git module.

See doc/savannah.txt for details on Git server access for users and
developers.

The current Git trees are web-browsable:
  http://git.savannah.gnu.org/cgit/lwip.git
  http://git.savannah.gnu.org/cgit/lwip/lwip-contrib.git

Submit patches and bugs via the lwIP project page:
  http://savannah.nongnu.org/projects/lwip/

Continuous integration builds (GCC, clang):
  https://travis-ci.org/yarrick/lwip-merged


DOCUMENTATION

Self documentation of the source code is regularly extracted from the current
Git sources and is available from this web page:
  http://www.nongnu.org/lwip/

There is now a constantly growing wiki about lwIP at
  http://lwip.wikia.com/wiki/LwIP_Wiki

Also, there are mailing lists you can subscribe at
  http://savannah.nongnu.org/mail/?group=lwip
plus searchable archives:
  http://lists.nongnu.org/archive/html/lwip-users/
  http://lists.nongnu.org/archive/html/lwip-devel/

lwIP was originally written by Adam Dunkels:
  http://dunkels.com/adam/

Reading Adam's papers, the files in docs/, browsing the source code
documentation and browsing the mailing list archives is a good way to
become familiar with the design of lwIP.

Adam Dunkels <adam@sics.se>
Leon Woestenberg <leon.woestenberg@gmx.net>