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tcp: Never hash match closed connections

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>From a practical point of view, when a TCP connection ends, whether by
FIN or by RST, we set the CLOSED event, then some time later we remove the
connection from the hash table and clean it up.  However, from a protocol
point of view, once it's closed, it's gone, and any new packets with
matching addresses and ports are either forming a new connection, or are
invalid packets to discard.

Enforce these semantics in the TCP hash logic by never hash matching closed
connections.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-09-08 11:49:49 +10:00 committed by Stefano Brivio
parent 805dd109a4
commit 5fb376de6e
1 changed files with 1 additions and 1 deletions
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tcp.c
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@ -1146,7 +1146,7 @@ static int tcp_hash_match(const struct tcp_tap_conn *conn,
const union inany_addr *faddr, const union inany_addr *faddr,
in_port_t eport, in_port_t fport) in_port_t eport, in_port_t fport)
{ {
if (inany_equals(&conn->faddr, faddr) && if (conn->events != CLOSED && inany_equals(&conn->faddr, faddr) &&
conn->eport == eport && conn->fport == fport) conn->eport == eport && conn->fport == fport)
return 1; return 1;