* add ipv6 to xnet.StackAsync
* dns improvements
* improve DNS workings of StackAsync
* add tentative ICMPv6
* work on prefixes and fix some small bugs, plan UDP/TCP6
* fix bugs in StackAsync and ipv4.Prefix.Contains
* update arpsubtable
* completely remove legacy internet.StackIP for StackIPv4/v6
* ipv4/ipv6 tcp/udp
* add TCP6/UDP6 dialing APIs
* add xnet.Stack6 interface
* more ipv6 integration into StackAsync; various tweaks to lneto and documentation+TODOs
* add stack6 tests
* replace netip.Prefix with ipv4.Prefix where it makes sense
* remove old fuzz corpus and stick to using PCG for seeding fuzz test
* polish up drain logic and reduce action search space
* improve fuzzing debug prints
* more fuzz fixes also formatter capture printer fixes
* refactor StackSeeded test
* fix challenge ack infinite packet bug
* more expressive challenge satisfy
* remove printing
* tcp: remove retransmit logic entirely; add duplicate ack counting to ControlBlock
* retransmit implemented in nice simple straightforward way
* narrow down retransmission cases
* remove old timing tests
* add ControlBlock retransmit test
* add failing handler test
* reworking payload length semantic meaning in code
* fix establish conn logic
* clean up tests and add TCB dupack generation and test it
* catch pending retransmit satisfy in test
* add fuzz test for control block
* bugfix: be more strict in what is considered dupack
* add IncomingIsDupACK docs
* limit queue of retransmits
* protect retransmit overflow from incorrectly updating nxt
* fix for #58
* add fixes for both retransmit and fuzz failure found
* fix infinite challenge ack due to RST+SYN+FIN corrupt packet in SYNRCV state
* fuzz: previous recovery ack path led to infinite transmit
* fuzz: calculate CRCs when fuzzing to reduce search space to non-CRC error cases
* add local fuzz corpus to tests
* add more cases to fuzz corpus
* tcp: bugfix for seq not in snd/rcv.wnd error
* accept dupe ACKs for window updates and prevent decrement of UNA
* add fixes for incorrect tcp functioning
* remove Conn.Available* methods in favor of Conn.Free* methods due to ambiguous name
* tcp: mss honoring; accept syn with ECE/CWR flags; add RSTQueue type
* tcp: move option logic to own file
* remove prints in pcap
* add MSS send threshold inspired by linux/freebsd/lwip thresh
* claude suggests a way forward
* add timing to capture printer
* add pcap.Flags
* fix ICMP CRC calculation and add test
* bugfix: still send data on half-close state(close-wait)
* fix pcap test
* begin reviewing TCP listener
* begin adding listener tests
* adding TestExchange implementation
* split out legacy and Step tests
* move listener to tcp package
* fix up tcp tests taking very long
* add xnet.TCPPool and work on TCPPool semantics
* xnet: TCPPool only accepts established connections
* xnet: getting to bottom of panic in xnet.Listener
* xnet: improve listener tests
* fix several data races in testing fixtures
* fix more synchronization things in listener test
* finalize tcplistener test
Pat Whittingslow