From fff3269907897ee91406ece125795f53e722677e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Jun 2012 01:47:50 +0000 Subject: tcp: reflect SYN queue_mapping into SYNACK packets While testing how linux behaves on SYNFLOOD attack on multiqueue device (ixgbe), I found that SYNACK messages were dropped at Qdisc level because we send them all on a single queue. Obvious choice is to reflect incoming SYN packet @queue_mapping to SYNACK packet. Under stress, my machine could only send 25.000 SYNACK per second (for 200.000 incoming SYN per second). NIC : ixgbe with 16 rx/tx queues. After patch, not a single SYNACK is dropped. Signed-off-by: Eric Dumazet Cc: Hans Schillstrom Cc: Jesper Dangaard Brouer Cc: Neal Cardwell Cc: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a43b87d..c8d28c4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -824,7 +824,8 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, */ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst, struct request_sock *req, - struct request_values *rvp) + struct request_values *rvp, + u16 queue_mapping) { const struct inet_request_sock *ireq = inet_rsk(req); struct flowi4 fl4; @@ -840,6 +841,7 @@ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst, if (skb) { __tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr); + skb_set_queue_mapping(skb, queue_mapping); err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr, ireq->rmt_addr, ireq->opt); @@ -854,7 +856,7 @@ static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req, struct request_values *rvp) { TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS); - return tcp_v4_send_synack(sk, NULL, req, rvp); + return tcp_v4_send_synack(sk, NULL, req, rvp, 0); } /* @@ -1422,7 +1424,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) tcp_rsk(req)->snt_synack = tcp_time_stamp; if (tcp_v4_send_synack(sk, dst, req, - (struct request_values *)&tmp_ext) || + (struct request_values *)&tmp_ext, + skb_get_queue_mapping(skb)) || want_cookie) goto drop_and_free; -- cgit v1.1