From dc6ef6be52154490c5c03f742e28bc781cc751b2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 16 Oct 2015 13:00:01 -0700 Subject: [PATCH] tcp: do not set queue_mapping on SYNACK At the time of commit fff326990789 ("tcp: reflect SYN queue_mapping into SYNACK packets") we had little ways to cope with SYN floods. We no longer need to reflect incoming skb queue mappings, and instead can pick a TX queue based on cpu cooking the SYNACK, with normal XPS affinities. Note that all SYNACK retransmits were picking TX queue 0, this no longer is a win given that SYNACK rtx are now distributed on all cpus. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/tcp.h | 2 +- net/ipv4/ip_output.c | 1 - net/ipv4/tcp_input.c | 4 ++-- net/ipv4/tcp_ipv4.c | 2 -- net/ipv4/tcp_output.c | 2 +- net/ipv6/tcp_ipv6.c | 2 -- 6 files changed, 4 insertions(+), 9 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index a6be56d5f0e3..eed94fc355c1 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1716,7 +1716,7 @@ struct tcp_request_sock_ops { __u32 (*init_seq)(const struct sk_buff *skb); int (*send_synack)(const struct sock *sk, struct dst_entry *dst, struct flowi *fl, struct request_sock *req, - u16 queue_mapping, struct tcp_fastopen_cookie *foc, + struct tcp_fastopen_cookie *foc, bool attach_req); }; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 67404e1fe7d4..50e29737b584 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1596,7 +1596,6 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, arg->csumoffset) = csum_fold(csum_add(nskb->csum, arg->csum)); nskb->ip_summed = CHECKSUM_NONE; - skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb)); ip_push_pending_frames(sk, &fl4); } out: diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 3b35c3f4d268..944eaca69115 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6236,7 +6236,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, } if (fastopen_sk) { af_ops->send_synack(fastopen_sk, dst, &fl, req, - skb_get_queue_mapping(skb), &foc, false); + &foc, false); /* Add the child socket directly into the accept queue */ inet_csk_reqsk_queue_add(sk, req, fastopen_sk); sk->sk_data_ready(sk); @@ -6247,7 +6247,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, if (!want_cookie) inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT); af_ops->send_synack(sk, dst, &fl, req, - skb_get_queue_mapping(skb), &foc, !want_cookie); + &foc, !want_cookie); if (want_cookie) goto drop_and_free; } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 9c68cf3762c4..30dd45c1f568 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -821,7 +821,6 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, struct flowi *fl, struct request_sock *req, - u16 queue_mapping, struct tcp_fastopen_cookie *foc, bool attach_req) { @@ -839,7 +838,6 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, if (skb) { __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); - skb_set_queue_mapping(skb, queue_mapping); err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, ireq->ir_rmt_addr, ireq->opt); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 6e79fcb0addb..19adedb8c5cc 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3518,7 +3518,7 @@ int tcp_rtx_synack(const struct sock *sk, struct request_sock *req) int res; tcp_rsk(req)->txhash = net_tx_rndhash(); - res = af_ops->send_synack(sk, NULL, &fl, req, 0, NULL, true); + res = af_ops->send_synack(sk, NULL, &fl, req, NULL, true); if (!res) { TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index acb06f86f372..f495d189f5e0 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -437,7 +437,6 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, struct flowi *fl, struct request_sock *req, - u16 queue_mapping, struct tcp_fastopen_cookie *foc, bool attach_req) { @@ -462,7 +461,6 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, if (np->repflow && ireq->pktopts) fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts)); - skb_set_queue_mapping(skb, queue_mapping); err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass); err = net_xmit_eval(err); } -- GitLab