soreuseport: fast reuseport TCP socket selection

This change extends the fast SO_REUSEPORT socket lookup implemented
for UDP to TCP.  Listener sockets with SO_REUSEPORT and the same
receive address are additionally added to an array for faster
random access.  This means that only a single socket from the group
must be found in the listener list before any socket in the group can
be used to receive a packet.  Previously, every socket in the group
needed to be considered before handing off the incoming packet.

This feature also exposes the ability to use a BPF program when
selecting a socket from a reuseport group.

Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 8240339..50f635c 100644 (file)
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -207,7 +207,10 @@ void inet_hashinfo_init(struct inet_hashinfo *h);
 
 bool inet_ehash_insert(struct sock *sk, struct sock *osk);
 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk);
-void __inet_hash(struct sock *sk, struct sock *osk);
+int __inet_hash(struct sock *sk, struct sock *osk,
+               int (*saddr_same)(const struct sock *sk1,
+                                 const struct sock *sk2,
+                                 bool match_wildcard));
 int inet_hash(struct sock *sk);
 void inet_unhash(struct sock *sk);
 

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 12c8d38..c16a2e6 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -24,6 +24,7 @@
 #include <net/tcp_states.h>
 #include <net/xfrm.h>
 #include <net/tcp.h>
+#include <net/sock_reuseport.h>
 
 #ifdef INET_CSK_DEBUG
 const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
@@ -67,7 +68,8 @@ int inet_csk_bind_conflict(const struct sock *sk,
                        if ((!reuse || !sk2->sk_reuse ||
                            sk2->sk_state == TCP_LISTEN) &&
                            (!reuseport || !sk2->sk_reuseport ||
-                           (sk2->sk_state != TCP_TIME_WAIT &&
+                            rcu_access_pointer(sk->sk_reuseport_cb) ||
+                            (sk2->sk_state != TCP_TIME_WAIT &&
                             !uid_eq(uid, sock_i_uid(sk2))))) {
 
                                if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
@@ -132,6 +134,7 @@ again:
                                              sk->sk_state != TCP_LISTEN) ||
                                             (tb->fastreuseport > 0 &&
                                              sk->sk_reuseport &&
+                                             !rcu_access_pointer(sk->sk_reuseport_cb) &&
                                              uid_eq(tb->fastuid, uid))) &&
                                            (tb->num_owners < smallest_size || smallest_size == -1)) {
                                                smallest_size = tb->num_owners;
@@ -193,15 +196,18 @@ tb_found:
                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) {
+                     sk->sk_reuseport &&
+                     !rcu_access_pointer(sk->sk_reuseport_cb) &&
+                     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) ||
                                     (tb->fastreuseport > 0 &&
-                                     sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
+                                     sk->sk_reuseport &&
+                                     !rcu_access_pointer(sk->sk_reuseport_cb) &&
+                                     uid_eq(tb->fastuid, uid))) &&
                                    smallest_size != -1 && --attempts >= 0) {
                                        spin_unlock(&head->lock);
                                        goto again;

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 5e4290b..c0f9942 100644 (file)
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -20,10 +20,12 @@
 #include <linux/wait.h>
 #include <linux/vmalloc.h>
 
+#include <net/addrconf.h>
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
 #include <net/secure_seq.h>
 #include <net/ip.h>
+#include <net/sock_reuseport.h>
 
 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
                        const __u16 lport, const __be32 faddr,
@@ -215,6 +217,7 @@ struct sock *__inet_lookup_listener(struct net *net,
        unsigned int hash = inet_lhashfn(net, hnum);
        struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
        int score, hiscore, matches = 0, reuseport = 0;
+       bool select_ok = true;
        u32 phash = 0;
 
        rcu_read_lock();
@@ -230,6 +233,15 @@ begin:
                        if (reuseport) {
                                phash = inet_ehashfn(net, daddr, hnum,
                                                     saddr, sport);
+                               if (select_ok) {
+                                       struct sock *sk2;
+                                       sk2 = reuseport_select_sock(sk, phash,
+                                                                   skb, doff);
+                                       if (sk2) {
+                                               result = sk2;
+                                               goto found;
+                                       }
+                               }
                                matches = 1;
                        }
                } else if (score == hiscore && reuseport) {
@@ -247,11 +259,13 @@ begin:
        if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
                goto begin;
        if (result) {
+found:
                if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
                        result = NULL;
                else if (unlikely(compute_score(result, net, hnum, daddr,
                                  dif) < hiscore)) {
                        sock_put(result);
+                       select_ok = false;
                        goto begin;
                }
        }
@@ -450,34 +464,74 @@ bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
 }
 EXPORT_SYMBOL_GPL(inet_ehash_nolisten);
 
-void __inet_hash(struct sock *sk, struct sock *osk)
+static int inet_reuseport_add_sock(struct sock *sk,
+                                  struct inet_listen_hashbucket *ilb,
+                                  int (*saddr_same)(const struct sock *sk1,
+                                                    const struct sock *sk2,
+                                                    bool match_wildcard))
+{
+       struct sock *sk2;
+       struct hlist_nulls_node *node;
+       kuid_t uid = sock_i_uid(sk);
+
+       sk_nulls_for_each_rcu(sk2, node, &ilb->head) {
+               if (sk2 != sk &&
+                   sk2->sk_family == sk->sk_family &&
+                   ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
+                   sk2->sk_bound_dev_if == sk->sk_bound_dev_if &&
+                   sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
+                   saddr_same(sk, sk2, false))
+                       return reuseport_add_sock(sk, sk2);
+       }
+
+       /* Initial allocation may have already happened via setsockopt */
+       if (!rcu_access_pointer(sk->sk_reuseport_cb))
+               return reuseport_alloc(sk);
+       return 0;
+}
+
+int __inet_hash(struct sock *sk, struct sock *osk,
+                int (*saddr_same)(const struct sock *sk1,
+                                  const struct sock *sk2,
+                                  bool match_wildcard))
 {
        struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
        struct inet_listen_hashbucket *ilb;
+       int err = 0;
 
        if (sk->sk_state != TCP_LISTEN) {
                inet_ehash_nolisten(sk, osk);
-               return;
+               return 0;
        }
        WARN_ON(!sk_unhashed(sk));
        ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 
        spin_lock(&ilb->lock);
+       if (sk->sk_reuseport) {
+               err = inet_reuseport_add_sock(sk, ilb, saddr_same);
+               if (err)
+                       goto unlock;
+       }
        __sk_nulls_add_node_rcu(sk, &ilb->head);
        sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+unlock:
        spin_unlock(&ilb->lock);
+
+       return err;
 }
 EXPORT_SYMBOL(__inet_hash);
 
 int inet_hash(struct sock *sk)
 {
+       int err = 0;
+
        if (sk->sk_state != TCP_CLOSE) {
                local_bh_disable();
-               __inet_hash(sk, NULL);
+               err = __inet_hash(sk, NULL, ipv4_rcv_saddr_equal);
                local_bh_enable();
        }
 
-       return 0;
+       return err;
 }
 EXPORT_SYMBOL_GPL(inet_hash);
 
@@ -496,6 +550,8 @@ void inet_unhash(struct sock *sk)
                lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 
        spin_lock_bh(lock);
+       if (rcu_access_pointer(sk->sk_reuseport_cb))
+               reuseport_detach_sock(sk);
        done = __sk_nulls_del_node_init_rcu(sk);
        if (done)
                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index be0b218..ac3cedb 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -356,8 +356,8 @@ EXPORT_SYMBOL(udp_lib_get_port);
  * match_wildcard == false: addresses must be exactly the same, i.e.
  *                          0.0.0.0 only equals to 0.0.0.0
  */
-static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2,
-                               bool match_wildcard)
+int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2,
+                        bool match_wildcard)
 {
        struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 

diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 36c3f01..532c3ef 100644 (file)
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -26,6 +26,7 @@
 #include <net/ip6_route.h>
 #include <net/sock.h>
 #include <net/inet6_connection_sock.h>
+#include <net/sock_reuseport.h>
 
 int inet6_csk_bind_conflict(const struct sock *sk,
                            const struct inet_bind_bucket *tb, bool relax)
@@ -48,6 +49,7 @@ int inet6_csk_bind_conflict(const struct sock *sk,
                        if ((!reuse || !sk2->sk_reuse ||
                             sk2->sk_state == TCP_LISTEN) &&
                            (!reuseport || !sk2->sk_reuseport ||
+                            rcu_access_pointer(sk->sk_reuseport_cb) ||
                             (sk2->sk_state != TCP_TIME_WAIT &&
                              !uid_eq(uid,
                                      sock_i_uid((struct sock *)sk2))))) {

diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 004345d..70f2628 100644 (file)
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -17,11 +17,13 @@
 #include <linux/module.h>
 #include <linux/random.h>
 
+#include <net/addrconf.h>
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
 #include <net/inet6_hashtables.h>
 #include <net/secure_seq.h>
 #include <net/ip.h>
+#include <net/sock_reuseport.h>
 
 u32 inet6_ehashfn(const struct net *net,
                  const struct in6_addr *laddr, const u16 lport,
@@ -131,6 +133,7 @@ struct sock *inet6_lookup_listener(struct net *net,
        const struct hlist_nulls_node *node;
        struct sock *result;
        int score, hiscore, matches = 0, reuseport = 0;
+       bool select_ok = true;
        u32 phash = 0;
        unsigned int hash = inet_lhashfn(net, hnum);
        struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
@@ -148,6 +151,15 @@ begin:
                        if (reuseport) {
                                phash = inet6_ehashfn(net, daddr, hnum,
                                                      saddr, sport);
+                               if (select_ok) {
+                                       struct sock *sk2;
+                                       sk2 = reuseport_select_sock(sk, phash,
+                                                                   skb, doff);
+                                       if (sk2) {
+                                               result = sk2;
+                                               goto found;
+                                       }
+                               }
                                matches = 1;
                        }
                } else if (score == hiscore && reuseport) {
@@ -165,11 +177,13 @@ begin:
        if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
                goto begin;
        if (result) {
+found:
                if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
                        result = NULL;
                else if (unlikely(compute_score(result, net, hnum, daddr,
                                  dif) < hiscore)) {
                        sock_put(result);
+                       select_ok = false;
                        goto begin;
                }
        }
@@ -283,7 +297,7 @@ int inet6_hash(struct sock *sk)
 {
        if (sk->sk_state != TCP_CLOSE) {
                local_bh_disable();
-               __inet_hash(sk, NULL);
+               __inet_hash(sk, NULL, ipv6_rcv_saddr_equal);
                local_bh_enable();
        }