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jeremybenn |
INTRODUCTION
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lwIP is a small independent implementation of the TCP/IP protocol
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suite that has been developed by Adam Dunkels at the Computer and
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Networks Architectures (CNA) lab at the Swedish Institute of Computer
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Science (SICS).
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The focus of the lwIP TCP/IP implementation is to reduce the RAM usage
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while still having a full scale TCP. This making lwIP suitable for use
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in embedded systems with tenths of kilobytes of free RAM and room for
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around 40 kilobytes of code ROM.
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FEATURES
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* IP (Internet Protocol) including packet forwarding over multiple
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network interfaces
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* ICMP (Internet Control Message Protocol) for network maintenance
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and debugging
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* UDP (User Datagram Protocol) including experimental UDP-lite
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extensions
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* TCP (Transmission Control Protocol) with congestion control, RTT
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estimation and fast recovery/fast retransmit
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* Specialized API for enhanced performance
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* Optional Berkeley socket API
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LICENSE
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lwIP is freely available under a BSD license.
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DEVELOPMENT
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lwIP has grown into an excellent TCP/IP stack for embedded devices,
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and developers using the stack often submit bug fixes, improvements,
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and additions to the stack to further increase its usefulness.
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Development of lwIP is hosted on Savannah, a central point for
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software development, maintenance and distribution. Everyone can
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help improve lwIP by use of Savannah's interface, CVS and the
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mailing list. A core team of developers will commit changes to the
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CVS source tree.
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The lwIP TCP/IP stack is maintained in the 'lwip' CVS module and
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contributions (such as platform ports) are in the 'contrib' module.
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The CVS main trunk is the stable branch, which contains bug fixes and
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tested features. The latest stable branch can be checked out by doing:
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cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip login
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cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip co lwip
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The 'STABLE' tag in the stable branch will represent the most stable
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revision (which may be somewhat older to protect us from errors
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introduced by merges). This 'STABLE' tagged version can be checked out
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by doing:
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cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip login
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cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip co -r STABLE lwip
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The 'DEVEL' branch is the active development branch, which contains
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bleeding edge changes, and may be instable. It can be checkout by doing:
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cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip login
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cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip co -r DEVEL lwip
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The current contrib CVS tree can be checked out by doing:
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cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip login
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cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/lwip co contrib
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Last night's CVS tar ball can be downloaded from:
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http://savannah.gnu.org/cvs.backups/lwip.tar.gz
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The current CVS trees are web-browsable:
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http://savannah.nongnu.org/cgi-bin/viewcvs/lwip/lwip/
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http://savannah.nongnu.org/cgi-bin/viewcvs/lwip/contrib/
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Submit patches and bugs via the lwIP project page:
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http://savannah.nongnu.org/projects/lwip/
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DOCUMENTATION
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The original out-dated homepage of lwIP and Adam Dunkels' papers on
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lwIP are at the official lwIP home page:
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http://www.sics.se/~adam/lwip/
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Self documentation of the source code is regularly extracted from the
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current CVS sources and is available from this web page:
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http://www.nongnu.org/lwip/
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Reading Adam's papers, the files in docs/, browsing the source code
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documentation and browsing the mailing list archives is a good way to
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become familiar with the design of lwIP.
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Adam Dunkels
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Leon Woestenberg
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