Modelled after UDP, add limited TCP support to the boot net stack. The socket
works by queuing received packets as well as sent packets that have not yet
been ACK'ed. Some known issues are documented, especially there's only limited
congestion control. I.e., we send immediately and in unlimited quantity, thus
its use should be restricted to local networks, and due to a fixed window size
there is potential for our socket being overrun with data packets before they
are read. Some corner cases like wrapping sequence numbers may cause a timeout.
The TCP implementation is based on Andrew S. Tanenbaum's "Computer Networks",
4th ed., as well as lecture notes from Prof. W. Effelsberg, the relevant RFCs
and Wikipedia. The pseudo-random number Galois LFSR used for the sequence
number was suggested by Endre Varga.
Since the code is unlikely to get much smaller, better merge it now so that
subsequent changes get easier to review. No platform actively uses TCP sockets
yet, and the receiving code has been reviewed for endianness issues and should
terminate okay after verifying the checksum if no sockets are open.
Based on a version tested with custom code (#5240) as well as with iSCSI.
Compile-tested boot_loader_openfirmware, pxehaiku-loader with gcc4 and
haiku_loader with gcc2. Closes ticket #5240.
Changes from #5240 proposed patch:
* Various bug fixes related to queuing, some memory leaks fixed.
* Never bump the sequence number when dequeuing a packet. It's done afterwards.
* Don't bump the sequence number again when resending the queue or ACK'ing.
* Aggressively ACK while waiting for packets.
* Don't queue sent ACK-only packets.
* More trace output, esp. for queue inspection.
* Adapted use of TCP header flags to r38434.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@38472 a95241bf-73f2-0310-859d-f6bbb57e9c96
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