connect-scan: raw non-blocking connect() + poll(POLLOUT) + SO_ERROR via std.os.linux (std.Io.net connect-with-timeout is unimplemented in 0.16); own sized std.Io.Threaded with N io.async workers off a mutex+token-bucket dispenser; --backend connect / --connect, --concurrency, --connect-timeout.
cloud/VM detection: two-socket AF_PACKET self-probe (send on one, observe the tagged frame on a second - single-socket cannot see its own send); --backend auto checks CAP_NET_RAW + egress and auto-falls-back to connect with a notice; forced raw backend disables fallback and hard-fails; zero-response raw scan hints --connect.
raw IPv6 SYN: packet.Addr union result + RFC5952 v6 render; Ipv6Hdr + pseudoChecksum6/tcpChecksum6; 128-bit SipHash cookie (generate6/seq6); parseIpv6, resolveSrcIp6 (/proc/net/if_inet6), defaultGateway6 (/proc/net/ipv6_route); Engine6 (bounded prefix, RFC6890 reserved floor, ::/0 reject, host cap); SynTemplate6; classifyTcp6 + ICMPv6 type1; ndp.zig NDP neighbor resolution; runV6Scan dispatch; connect-path v6 rides the connect engine. v6 scope = TCP SYN.
240 tests Debug+ReleaseSafe (-Dxdp on/off); KAT + two-namespace netns e2e proven on the wire; two read-only audits, 0 Critical/High/Medium, all findings fixed in-phase.
OS-realistic SYN templates (Linux/Windows/macOS/masscan JA4T option chains
plus varying IP-id), Poisson jitter, source-port rotation (RX recomputes off
the reply, zero classify changes), scoped RST-suppression (iptables plus
ambient CAP_NET_ADMIN, self-healing delete-before-insert), decoys (bogon-free
RND, real probe always sent), and FIN/NULL/Xmas/Maimon/ACK/Window flag scans
with per-mode cookie matching plus State.unfiltered.
Dead theater (idle scan, fragmentation, TTL, MAC/source-route spoof, badsum)
omitted and documented as obsolete with citations.
Cursor-based TX emission with token refund plus cold-start pacing; non-stealth
path byte-identical to M7.
classify.zig pure frame parser: SYN-ACK -> open, RST/ACK -> closed,
ICMP type-3 {1,2,3,9,10,13} -> filtered, every verdict gated on a
wrapping SipHash cookie re-check (ack == seq+1 for replies, inner seq
== cookie for ICMP) so spoofed/stale frames are dropped state-free;
byte-offset readInt parsing, fully length-guarded. dedup.zig power-of-2
open-addressed (ip,port) set, single-owned allocator, grows at load
factor with a bounded probe (never wedges). rx.zig receive engine
generic over an injected Source + Sink (proven over hand-built frames),
Io.Queue found-host handoff across producer/consumer fibers, and a
privileged AF_PACKET Receiver (poll-bounded drain with a hard deadline,
ignore-outgoing, EINTR-retry, errno-gated, fail-closed on missing
CAP_NET_RAW). scan subcommand shares one per-run cookie across the TX
template + RX validation; consumer uses a dedicated allocator to keep
the producer/consumer fibers race-free. netutil.zig factors the shared
arg-parse/iface-resolve helpers out of txcmd. Proven end-to-end with a
live SYN scan inside a unshare -r -n netns over a veth pair
(open/closed against a real listener, dedup verified). Green Debug +
ReleaseSafe, leak-free, 61 unit tests.
CarterPerez-dev