From da5e36308d9f7151845018369148201a5d28b46d Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Tue, 22 Jan 2013 09:50:24 +0000 Subject: soreuseport: TCP/IPv4 implementation Allow multiple listener sockets to bind to the same port. Motivation for soresuseport would be something like a web server binding to port 80 running with multiple threads, where each thread might have it's own listener socket. This could be done as an alternative to other models: 1) have one listener thread which dispatches completed connections to workers. 2) accept on a single listener socket from multiple threads. In case #1 the listener thread can easily become the bottleneck with high connection turn-over rate. In case #2, the proportion of connections accepted per thread tends to be uneven under high connection load (assuming simple event loop: while (1) { accept(); process() }, wakeup does not promote fairness among the sockets. We have seen the disproportion to be as high as 3:1 ratio between thread accepting most connections and the one accepting the fewest. With so_reusport the distribution is uniform. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/inet_connection_sock.c | 48 +++++++++++++++++++++++++++++++---------- net/ipv4/inet_hashtables.c | 28 ++++++++++++++++++------ net/ipv4/tcp_ipv4.c | 4 +++- 3 files changed, 62 insertions(+), 18 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index d0670f00d52..8bb623d357a 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -59,6 +59,8 @@ int inet_csk_bind_conflict(const struct sock *sk, struct sock *sk2; struct hlist_node *node; int reuse = sk->sk_reuse; + int reuseport = sk->sk_reuseport; + kuid_t uid = sock_i_uid((struct sock *)sk); /* * Unlike other sk lookup places we do not check @@ -73,8 +75,11 @@ int inet_csk_bind_conflict(const struct sock *sk, (!sk->sk_bound_dev_if || !sk2->sk_bound_dev_if || sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) { - if (!reuse || !sk2->sk_reuse || - sk2->sk_state == TCP_LISTEN) { + if ((!reuse || !sk2->sk_reuse || + sk2->sk_state == TCP_LISTEN) && + (!reuseport || !sk2->sk_reuseport || + (sk2->sk_state != TCP_TIME_WAIT && + !uid_eq(uid, sock_i_uid(sk2))))) { const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2); if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) || sk2_rcv_saddr == sk_rcv_saddr(sk)) @@ -106,6 +111,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum) int ret, attempts = 5; struct net *net = sock_net(sk); int smallest_size = -1, smallest_rover; + kuid_t uid = sock_i_uid(sk); local_bh_disable(); if (!snum) { @@ -125,9 +131,12 @@ again: spin_lock(&head->lock); inet_bind_bucket_for_each(tb, node, &head->chain) if (net_eq(ib_net(tb), net) && tb->port == rover) { - if (tb->fastreuse > 0 && - sk->sk_reuse && - sk->sk_state != TCP_LISTEN && + if (((tb->fastreuse > 0 && + sk->sk_reuse && + sk->sk_state != TCP_LISTEN) || + (tb->fastreuseport > 0 && + sk->sk_reuseport && + uid_eq(tb->fastuid, uid))) && (tb->num_owners < smallest_size || smallest_size == -1)) { smallest_size = tb->num_owners; smallest_rover = rover; @@ -185,14 +194,17 @@ tb_found: if (sk->sk_reuse == SK_FORCE_REUSE) goto success; - if (tb->fastreuse > 0 && - sk->sk_reuse && sk->sk_state != TCP_LISTEN && + if (((tb->fastreuse > 0 && + sk->sk_reuse && sk->sk_state != TCP_LISTEN) || + (tb->fastreuseport > 0 && + sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && smallest_size == -1) { goto success; } else { ret = 1; if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) { - if (sk->sk_reuse && sk->sk_state != TCP_LISTEN && + if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) || + (sk->sk_reuseport && uid_eq(tb->fastuid, uid))) && smallest_size != -1 && --attempts >= 0) { spin_unlock(&head->lock); goto again; @@ -212,9 +224,23 @@ tb_not_found: tb->fastreuse = 1; else tb->fastreuse = 0; - } else if (tb->fastreuse && - (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) - tb->fastreuse = 0; + if (sk->sk_reuseport) { + tb->fastreuseport = 1; + tb->fastuid = uid; + } else { + tb->fastreuseport = 0; + tb->fastuid = 0; + } + } else { + if (tb->fastreuse && + (!sk->sk_reuse || sk->sk_state == TCP_LISTEN)) + tb->fastreuse = 0; + if (tb->fastreuseport && + (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))) { + tb->fastreuseport = 0; + tb->fastuid = 0; + } + } success: if (!inet_csk(sk)->icsk_bind_hash) inet_bind_hash(sk, tb, snum); diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index fa3ae814871..0ce0595d986 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -39,6 +39,7 @@ struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep, write_pnet(&tb->ib_net, hold_net(net)); tb->port = snum; tb->fastreuse = 0; + tb->fastreuseport = 0; tb->num_owners = 0; INIT_HLIST_HEAD(&tb->owners); hlist_add_head(&tb->node, &head->chain); @@ -151,16 +152,16 @@ static inline int compute_score(struct sock *sk, struct net *net, if (net_eq(sock_net(sk), net) && inet->inet_num == hnum && !ipv6_only_sock(sk)) { __be32 rcv_saddr = inet->inet_rcv_saddr; - score = sk->sk_family == PF_INET ? 1 : 0; + score = sk->sk_family == PF_INET ? 2 : 1; if (rcv_saddr) { if (rcv_saddr != daddr) return -1; - score += 2; + score += 4; } if (sk->sk_bound_dev_if) { if (sk->sk_bound_dev_if != dif) return -1; - score += 2; + score += 4; } } return score; @@ -176,6 +177,7 @@ static inline int compute_score(struct sock *sk, struct net *net, struct sock *__inet_lookup_listener(struct net *net, struct inet_hashinfo *hashinfo, + const __be32 saddr, __be16 sport, const __be32 daddr, const unsigned short hnum, const int dif) { @@ -183,17 +185,29 @@ struct sock *__inet_lookup_listener(struct net *net, struct hlist_nulls_node *node; unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; - int score, hiscore; + int score, hiscore, matches = 0, reuseport = 0; + u32 phash = 0; rcu_read_lock(); begin: result = NULL; - hiscore = -1; + hiscore = 0; sk_nulls_for_each_rcu(sk, node, &ilb->head) { score = compute_score(sk, net, hnum, daddr, dif); if (score > hiscore) { result = sk; hiscore = score; + reuseport = sk->sk_reuseport; + if (reuseport) { + phash = inet_ehashfn(net, daddr, hnum, + saddr, sport); + matches = 1; + } + } else if (score == hiscore && reuseport) { + matches++; + if (((u64)phash * matches) >> 32 == 0) + result = sk; + phash = next_pseudo_random32(phash); } } /* @@ -501,7 +515,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, inet_bind_bucket_for_each(tb, node, &head->chain) { if (net_eq(ib_net(tb), net) && tb->port == port) { - if (tb->fastreuse >= 0) + if (tb->fastreuse >= 0 || + tb->fastreuseport >= 0) goto next_port; WARN_ON(hlist_empty(&tb->owners)); if (!check_established(death_row, sk, @@ -518,6 +533,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, break; } tb->fastreuse = -1; + tb->fastreuseport = -1; goto ok; next_port: diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index c6ce9ca98d2..bbbdcc5c197 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -657,7 +657,8 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) * no RST generated if md5 hash doesn't match. */ sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev), - &tcp_hashinfo, ip_hdr(skb)->daddr, + &tcp_hashinfo, ip_hdr(skb)->saddr, + th->source, ip_hdr(skb)->daddr, ntohs(th->source), inet_iif(skb)); /* don't send rst if it can't find key */ if (!sk1) @@ -2074,6 +2075,7 @@ do_time_wait: case TCP_TW_SYN: { struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), &tcp_hashinfo, + iph->saddr, th->source, iph->daddr, th->dest, inet_iif(skb)); if (sk2) { -- cgit v1.2.3