Commit cb6cd2ce authored Jan 31, 2022 by Akhmat Karakotov Committed by David S. Miller Jan 31, 2022

tcp: Change SYN ACK retransmit behaviour to account for rehash

Disabling rehash behavior did not affect SYN ACK retransmits because hash
was forcefully changed bypassing the sk_rethink_hash function. This patch
adds a condition which checks for rehash mode before resetting hash.

Signed-off-by: Akhmat Karakotov <hmukos@yandex-team.ru>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e7b9bfd1

net/core/sock.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1452,7 +1452,8 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
		ret = -EINVAL;
		break;
		}
		sk->sk_txrehash = (u8)val;
		/* Paired with READ_ONCE() in tcp_rtx_synack() */
		WRITE_ONCE(sk->sk_txrehash, (u8)val);
		break;

		default:

net/ipv4/tcp_output.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4092,6 +4092,8 @@ int tcp_rtx_synack(const struct sock sk, struct request_sock req)
		struct flowi fl;
		int res;

		/* Paired with WRITE_ONCE() in sock_setsockopt() */
		if (READ_ONCE(sk->sk_txrehash) == SOCK_TXREHASH_ENABLED)
		tcp_rsk(req)->txhash = net_tx_rndhash();
		res = af_ops->send_synack(sk, NULL, &fl, req, NULL, TCP_SYNACK_NORMAL,
		NULL);