From f984003fdf2cc2dbd0ac55a47d9a4a25776fc2d0 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 8 Sep 2023 11:49:51 +1000 Subject: tcp: Correctly handle RST followed rapidly by SYN Although it's unlikely in practice, the guest could theoretically reset one TCP connection then immediately start a new one with the same addressses and ports, such that we get an RST then a SYN in the same batch of received packets in tcp_tap_handler(). We don't correctly handle that unlikely case, because when we receive the RST, we discard any remaining packets in the batch so we'd never see the SYN. This could happen in either tcp_tap_handler() or tcp_data_from_tap(). Correct that by returning 1, so that the caller will continue calling tcp_tap_handler() on subsequent packets allowing us to process any subsequent SYN. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'tcp.c') diff --git a/tcp.c b/tcp.c index 34c27f0..a1b5a72 100644 --- a/tcp.c +++ b/tcp.c @@ -2337,7 +2337,7 @@ static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, if (th->rst) { conn_event(c, conn, CLOSED); - return p->count - idx; + return 1; } len -= off; @@ -2570,7 +2570,7 @@ int tcp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, if (th->rst) { conn_event(c, conn, CLOSED); - return p->count - idx; + return 1; } if (th->ack && !(conn->events & ESTABLISHED)) -- cgit v1.2.3