From: Hans Wippel <hwippel@xxxxxxxxxxxxxxxxxx> Currently, the SMC experimental TCP option in a SYN packet is lost on the server side when SYN Cookies are active. However, the corresponding SYNACK sent back to the client contains the SMC option. This causes an inconsistent view of the SMC capabilities on the client and server. This patch disables the SMC option in the SYNACK when SYN Cookies are active to avoid this issue. Signed-off-by: Hans Wippel <hwippel@xxxxxxxxxxxxxxxxxx> Signed-off-by: Ursula Braun <ubraun@xxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp_output.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 383cac0ff0ec..22894514feae 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3199,6 +3199,8 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* Under synflood, we do not attach skb to a socket, * to avoid false sharing. */ + if (IS_ENABLED(CONFIG_SMC)) + ireq->smc_ok = 0; break; case TCP_SYNACK_FASTOPEN: /* sk is a const pointer, because we want to express multiple -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
