bd729751d7
Add the missing tcp_flags(), is_fin(), is_rst() helpers and upgrade advance_entry_state from a 3-parameter stub to a 4-parameter function that takes &PacketContext. This completes the WIP conntrack state machine with proper TCP tracking (SynSent, SynRecv, Established, FinWait, TimeWait, Close) and RST/session-timeout handling. Reference: Linux 7.x net/netfilter/nf_conntrack_proto_tcp.c (tcp_packet, nf_conntrack_tcp_packet state machine).