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>
Change-Id: I84cc6952d273fcb1b1dba7cbf31504ea135ecdae

1 files changed, 10 insertions, 4 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 0da1bd857edf..f6f3ee843d12 100644
--- 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 ||
@@ -157,6 +159,7 @@ 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;
@@ -225,15 +228,18 @@ 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;