tcp_hash_lookup() expects the port numbers in host order, but the TCP header, of course, has them in network order, so we need to switch them. However we call htons() (host to network) instead of ntohs() (network to host). This works because those do the same thing in practice (they only wouldn't on very strange theoretical platforms which are neither big nor little endian). But, having this the "wrong" way around is misleading, so switch it around. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tcp.c b/tcp.c index f506cfd..bf58938 100644 --- a/tcp.c +++ b/tcp.c @@ -2532,7 +2532,7 @@ int tcp_tap_handler(struct ctx *c, uint8_t pif, int af, optlen = MIN(optlen, ((1UL << 4) /* from doff width */ - 6) * 4UL); opts = packet_get(p, idx, sizeof(*th), optlen, NULL); - conn = tcp_hash_lookup(c, af, daddr, htons(th->source), htons(th->dest)); + conn = tcp_hash_lookup(c, af, daddr, ntohs(th->source), ntohs(th->dest)); /* New connection from tap */ if (!conn) { -- 2.43.0