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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 <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-06-01 01:47:50 +00:00 committed by David S. Miller
parent 7433819a1e
commit fff3269907
2 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
net/ipv4/tcp_ipv4.c
View File

@ -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;

9
net/ipv6/tcp_ipv6.c
View File

@ -476,7 +476,8 @@ out:
static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
struct request_values *rvp)
struct request_values *rvp,
u16 queue_mapping)
{
struct inet6_request_sock *treq = inet6_rsk(req);
struct ipv6_pinfo *np = inet6_sk(sk);
@ -513,6 +514,7 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
fl6.daddr = treq->rmt_addr;
skb_set_queue_mapping(skb, queue_mapping);
err = ip6_xmit(sk, skb, &fl6, opt, np->tclass);
err = net_xmit_eval(err);
}
@ -528,7 +530,7 @@ static int tcp_v6_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_v6_send_synack(sk, req, rvp);
return tcp_v6_send_synack(sk, req, rvp, 0);
}
static void tcp_v6_reqsk_destructor(struct request_sock *req)
@ -1213,7 +1215,8 @@ have_isn:
security_inet_conn_request(sk, skb, req);
if (tcp_v6_send_synack(sk, req,
(struct request_values *)&tmp_ext) ||
(struct request_values *)&tmp_ext,
skb_get_queue_mapping(skb)) ||
want_cookie)
goto drop_and_free;