Merge branch 'soreuseport'

Tom Herbert says:

====================
This series implements so_reuseport (SO_REUSEPORT socket option) for
TCP and UDP.  For TCP, so_reuseport allows multiple listener sockets
to be bound to the same port.  In the case of UDP, so_reuseport allows
multiple sockets to bind to the same port.  To prevent port hijacking
all sockets bound to the same port using so_reuseport must have the
same uid.  Received packets are distributed to multiple sockets bound
to the same port using a 4-tuple hash.

The motivating case for so_resuseport in TCP 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.

The TCP implementation has a problem in that the request sockets for a
listener are attached to a listener socket.  If a SYN is received, a
listener socket is chosen and request structure is created (SYN-RECV
state).  If the subsequent ack in 3WHS does not match the same port
by so_reusport, the connection state is not found (reset) and the
request structure is orphaned.  This scenario would occur when the
number of listener sockets bound to a port changes (new ones are
added, or old ones closed).  We are looking for a solution to this,
maybe allow multiple sockets to share the same request table...

The motivating case for so_reuseport in UDP would be something like a
DNS server.  An alternative would be to recv on the same socket from
multiple threads.  As in the case of TCP, the load across these threads
tends to be disproportionate and we also see a lot of contection on
the socket lock.  Note that SO_REUSEADDR already allows multiple UDP
sockets to bind to the same port, however there is no provision to
prevent hijacking and nothing to distribute packets across all the
sockets sharing the same bound port.  This patch does not change the
semantics of SO_REUSEADDR, but provides usable functionality of it
for unicast.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

29 files changed, 213 insertions, 70 deletions

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index 755702e..c519552 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -19,7 +19,7 @@
 #define SO_BROADCAST	0x0020
 #define SO_LINGER	0x0080
 #define SO_OOBINLINE	0x0100
-/* To add :#define SO_REUSEPORT 0x0200 */
+#define SO_REUSEPORT	0x0200
 
 #define SO_TYPE		0x1008
 #define SO_ERROR	0x1007
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index f3f38a0..51c6401 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -22,7 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index 406b583..50692b7 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -24,7 +24,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index d8e1132..595391f 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -22,7 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/h8300/include/uapi/asm/socket.h b/arch/h8300/include/uapi/asm/socket.h
index c8b87a8..43e3262 100644
--- a/arch/h8300/include/uapi/asm/socket.h
+++ b/arch/h8300/include/uapi/asm/socket.h
@@ -22,7 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index f390896..c567adc 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -31,7 +31,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 6a89515..519afa2 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -22,7 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 9d11a77..7e27236 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -28,8 +28,7 @@
 #define SO_LINGER	0x0080	/* Block on close of a reliable
 				   socket to transmit pending data.  */
 #define SO_OOBINLINE 0x0100	/* Receive out-of-band data in-band.  */
-#if 0
-To add: #define SO_REUSEPORT 0x0200	/* Allow local address and port reuse.  */
+#define SO_REUSEPORT 0x0200	/* Allow local address and port reuse.  */
 #endif
 
 #define SO_TYPE		0x1008	/* Compatible name for SO_STYLE.  */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index ab702c4..5c7c7c9 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -22,7 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index da2c8d3..526e4b9 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -13,7 +13,7 @@
 #define SO_BROADCAST	0x0020
 #define SO_LINGER	0x0080
 #define SO_OOBINLINE	0x0100
-/* To add :#define SO_REUSEPORT 0x0200 */
+#define SO_REUSEPORT	0x0200
 #define SO_SNDBUF	0x1001
 #define SO_RCVBUF	0x1002
 #define SO_SNDBUFFORCE	0x100a
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index e6ca318..a26dcae 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -29,7 +29,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_RCVLOWAT	16
 #define SO_SNDLOWAT	17
 #define SO_RCVTIMEO	18
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index 9ce60b6..f99eea7 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -28,7 +28,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index fbbba57..cbbad74 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -15,7 +15,7 @@
 #define SO_PEERCRED	0x0040
 #define SO_LINGER	0x0080
 #define SO_OOBINLINE	0x0100
-/* To add :#define SO_REUSEPORT 0x0200 */
+#define SO_REUSEPORT	0x0200
 #define SO_BSDCOMPAT    0x0400
 #define SO_RCVLOWAT     0x0800
 #define SO_SNDLOWAT     0x1000
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index dbf3164..35905cb 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -32,7 +32,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
+#define SO_REUSEPORT	15
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
 #define SO_RCVLOWAT	18
diff --git a/include/linux/random.h b/include/linux/random.h
index d984608..347ce55 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -74,4 +74,10 @@ static inline int arch_get_random_int(unsigned int *v)
 }
 #endif
 
+/* Pseudo random number generator from numerical recipes. */
+static inline u32 next_pseudo_random32(u32 seed)
+{
+	return seed * 1664525 + 1013904223;
+}
+
 #endif /* _LINUX_RANDOM_H */
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 9e34c87..7ca75cb 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -71,6 +71,8 @@ extern struct sock *__inet6_lookup_established(struct net *net,
 
 extern struct sock *inet6_lookup_listener(struct net *net,
 					  struct inet_hashinfo *hashinfo,
+					  const struct in6_addr *saddr,
+					  const __be16 sport,
 					  const struct in6_addr *daddr,
 					  const unsigned short hnum,
 					  const int dif);
@@ -88,7 +90,8 @@ static inline struct sock *__inet6_lookup(struct net *net,
 	if (sk)
 		return sk;
 
-	return inet6_lookup_listener(net, hashinfo, daddr, hnum, dif);
+	return inet6_lookup_listener(net, hashinfo, saddr, sport,
+				     daddr, hnum, dif);
 }
 
 static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 67a8fa0..7b2ae9d 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -81,7 +81,9 @@ struct inet_bind_bucket {
 	struct net		*ib_net;
 #endif
 	unsigned short		port;
-	signed short		fastreuse;
+	signed char		fastreuse;
+	signed char		fastreuseport;
+	kuid_t			fastuid;
 	int			num_owners;
 	struct hlist_node	node;
 	struct hlist_head	owners;
@@ -257,15 +259,19 @@ extern void inet_unhash(struct sock *sk);
 
 extern struct sock *__inet_lookup_listener(struct net *net,
 					   struct inet_hashinfo *hashinfo,
+					   const __be32 saddr,
+					   const __be16 sport,
 					   const __be32 daddr,
 					   const unsigned short hnum,
 					   const int dif);
 
 static inline struct sock *inet_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo,
+		__be32 saddr, __be16 sport,
 		__be32 daddr, __be16 dport, int dif)
 {
-	return __inet_lookup_listener(net, hashinfo, daddr, ntohs(dport), dif);
+	return __inet_lookup_listener(net, hashinfo, saddr, sport,
+				      daddr, ntohs(dport), dif);
 }
 
 /* Socket demux engine toys. */
@@ -358,7 +364,8 @@ static inline struct sock *__inet_lookup(struct net *net,
 	struct sock *sk = __inet_lookup_established(net, hashinfo,
 				saddr, sport, daddr, hnum, dif);
 
-	return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif);
+	return sk ? : __inet_lookup_listener(net, hashinfo, saddr, sport,
+					     daddr, hnum, dif);
 }
 
 static inline struct sock *inet_lookup(struct net *net,
diff --git a/include/net/netfilter/nf_tproxy_core.h b/include/net/netfilter/nf_tproxy_core.h
index 75ca929..36d9379 100644
--- a/include/net/netfilter/nf_tproxy_core.h
+++ b/include/net/netfilter/nf_tproxy_core.h
@@ -82,6 +82,7 @@ nf_tproxy_get_sock_v4(struct net *net, const u8 protocol,
 			break;
 		case NFT_LOOKUP_LISTENER:
 			sk = inet_lookup_listener(net, &tcp_hashinfo,
+						    saddr, sport,
 						    daddr, dport,
 						    in->ifindex);
 
@@ -151,6 +152,7 @@ nf_tproxy_get_sock_v6(struct net *net, const u8 protocol,
 			break;
 		case NFT_LOOKUP_LISTENER:
 			sk = inet6_lookup_listener(net, &tcp_hashinfo,
+						   saddr, sport,
 						   daddr, ntohs(dport),
 						   in->ifindex);
 
diff --git a/include/net/sock.h b/include/net/sock.h
index 5a34e2f..581dc6b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -140,6 +140,7 @@ typedef __u64 __bitwise __addrpair;
  *	@skc_family: network address family
  *	@skc_state: Connection state
  *	@skc_reuse: %SO_REUSEADDR setting
+ *	@skc_reuseport: %SO_REUSEPORT setting
  *	@skc_bound_dev_if: bound device index if != 0
  *	@skc_bind_node: bind hash linkage for various protocol lookup tables
  *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
@@ -179,7 +180,8 @@ struct sock_common {
 
 	unsigned short		skc_family;
 	volatile unsigned char	skc_state;
-	unsigned char		skc_reuse;
+	unsigned char		skc_reuse:4;
+	unsigned char		skc_reuseport:4;
 	int			skc_bound_dev_if;
 	union {
 		struct hlist_node	skc_bind_node;
@@ -297,6 +299,7 @@ struct sock {
 #define sk_family		__sk_common.skc_family
 #define sk_state		__sk_common.skc_state
 #define sk_reuse		__sk_common.skc_reuse
+#define sk_reuseport		__sk_common.skc_reuseport
 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
 #define sk_bind_node		__sk_common.skc_bind_node
 #define sk_prot			__sk_common.skc_prot
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 3f6a992..4ef3acb 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -22,8 +22,7 @@
 #define SO_PRIORITY	12
 #define SO_LINGER	13
 #define SO_BSDCOMPAT	14
-/* To add :#define SO_REUSEPORT 15 */
-
+#define SO_REUSEPORT	15
 #ifndef SO_PASSCRED /* powerpc only differs in these */
 #define SO_PASSCRED	16
 #define SO_PEERCRED	17
diff --git a/net/core/sock.c b/net/core/sock.c
index 8258fb7..235fb89 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -665,6 +665,9 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
 	case SO_REUSEADDR:
 		sk->sk_reuse = (valbool ? SK_CAN_REUSE : SK_NO_REUSE);
 		break;
+	case SO_REUSEPORT:
+		sk->sk_reuseport = valbool;
+		break;
 	case SO_TYPE:
 	case SO_PROTOCOL:
 	case SO_DOMAIN:
@@ -972,6 +975,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
 		v.val = sk->sk_reuse;
 		break;
 
+	case SO_REUSEPORT:
+		v.val = sk->sk_reuseport;
+		break;
+
 	case SO_KEEPALIVE:
 		v.val = sock_flag(sk, SOCK_KEEPOPEN);
 		break;
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index d0670f0..8bb623d 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 fa3ae81..0ce0595 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 c6ce9ca..bbbdcc5 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) {
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index cf6158f..e0610e4 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -139,6 +139,7 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 {
 	struct sock *sk2;
 	struct hlist_nulls_node *node;
+	kuid_t uid = sock_i_uid(sk);
 
 	sk_nulls_for_each(sk2, node, &hslot->head)
 		if (net_eq(sock_net(sk2), net) &&
@@ -147,6 +148,8 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
+		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
+		      !uid_eq(uid, sock_i_uid(sk2))) &&
 		    (*saddr_comp)(sk, sk2)) {
 			if (bitmap)
 				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
@@ -169,6 +172,7 @@ static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 {
 	struct sock *sk2;
 	struct hlist_nulls_node *node;
+	kuid_t uid = sock_i_uid(sk);
 	int res = 0;
 
 	spin_lock(&hslot2->lock);
@@ -179,6 +183,8 @@ static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
+		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
+		      !uid_eq(uid, sock_i_uid(sk2))) &&
 		    (*saddr_comp)(sk, sk2)) {
 			res = 1;
 			break;
@@ -337,26 +343,26 @@ static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 			!ipv6_only_sock(sk)) {
 		struct inet_sock *inet = inet_sk(sk);
 
-		score = (sk->sk_family == PF_INET ? 1 : 0);
+		score = (sk->sk_family == PF_INET ? 2 : 1);
 		if (inet->inet_rcv_saddr) {
 			if (inet->inet_rcv_saddr != daddr)
 				return -1;
-			score += 2;
+			score += 4;
 		}
 		if (inet->inet_daddr) {
 			if (inet->inet_daddr != saddr)
 				return -1;
-			score += 2;
+			score += 4;
 		}
 		if (inet->inet_dport) {
 			if (inet->inet_dport != sport)
 				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;
@@ -365,7 +371,6 @@ static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 /*
  * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
  */
-#define SCORE2_MAX (1 + 2 + 2 + 2)
 static inline int compute_score2(struct sock *sk, struct net *net,
 				 __be32 saddr, __be16 sport,
 				 __be32 daddr, unsigned int hnum, int dif)
@@ -380,21 +385,21 @@ static inline int compute_score2(struct sock *sk, struct net *net,
 		if (inet->inet_num != hnum)
 			return -1;
 
-		score = (sk->sk_family == PF_INET ? 1 : 0);
+		score = (sk->sk_family == PF_INET ? 2 : 1);
 		if (inet->inet_daddr) {
 			if (inet->inet_daddr != saddr)
 				return -1;
-			score += 2;
+			score += 4;
 		}
 		if (inet->inet_dport) {
 			if (inet->inet_dport != sport)
 				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;
@@ -409,19 +414,29 @@ static struct sock *udp4_lib_lookup2(struct net *net,
 {
 	struct sock *sk, *result;
 	struct hlist_nulls_node *node;
-	int score, badness;
+	int score, badness, matches = 0, reuseport = 0;
+	u32 hash = 0;
 
 begin:
 	result = NULL;
-	badness = -1;
+	badness = 0;
 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 		score = compute_score2(sk, net, saddr, sport,
 				      daddr, hnum, dif);
 		if (score > badness) {
 			result = sk;
 			badness = score;
-			if (score == SCORE2_MAX)
-				goto exact_match;
+			reuseport = sk->sk_reuseport;
+			if (reuseport) {
+				hash = inet_ehashfn(net, daddr, hnum,
+						    saddr, htons(sport));
+				matches = 1;
+			}
+		} else if (score == badness && reuseport) {
+			matches++;
+			if (((u64)hash * matches) >> 32 == 0)
+				result = sk;
+			hash = next_pseudo_random32(hash);
 		}
 	}
 	/*
@@ -431,9 +446,7 @@ begin:
 	 */
 	if (get_nulls_value(node) != slot2)
 		goto begin;
-
 	if (result) {
-exact_match:
 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 			result = NULL;
 		else if (unlikely(compute_score2(result, net, saddr, sport,
@@ -457,7 +470,8 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 	unsigned short hnum = ntohs(dport);
 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
-	int score, badness;
+	int score, badness, matches = 0, reuseport = 0;
+	u32 hash = 0;
 
 	rcu_read_lock();
 	if (hslot->count > 10) {
@@ -486,13 +500,24 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 	}
 begin:
 	result = NULL;
-	badness = -1;
+	badness = 0;
 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 		score = compute_score(sk, net, saddr, hnum, sport,
 				      daddr, dport, dif);
 		if (score > badness) {
 			result = sk;
 			badness = score;
+			reuseport = sk->sk_reuseport;
+			if (reuseport) {
+				hash = inet_ehashfn(net, daddr, hnum,
+						    saddr, htons(sport));
+				matches = 1;
+			}
+		} else if (score == badness && reuseport) {
+			matches++;
+			if (((u64)hash * matches) >> 32 == 0)
+				result = sk;
+			hash = next_pseudo_random32(hash);
 		}
 	}
 	/*
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 3064785..e4297a3 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -32,6 +32,9 @@ int inet6_csk_bind_conflict(const struct sock *sk,
 {
 	const struct sock *sk2;
 	const struct hlist_node *node;
+	int reuse = sk->sk_reuse;
+	int reuseport = sk->sk_reuseport;
+	int uid = sock_i_uid((struct sock *)sk);
 
 	/* We must walk the whole port owner list in this case. -DaveM */
 	/*
@@ -42,11 +45,17 @@ int inet6_csk_bind_conflict(const struct sock *sk,
 		if (sk != sk2 &&
 		    (!sk->sk_bound_dev_if ||
 		     !sk2->sk_bound_dev_if ||
-		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
-		    (!sk->sk_reuse || !sk2->sk_reuse ||
-		     sk2->sk_state == TCP_LISTEN) &&
-		     ipv6_rcv_saddr_equal(sk, sk2))
-			break;
+		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
+			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((struct sock *)sk2))))) {
+				if (ipv6_rcv_saddr_equal(sk, sk2))
+					break;
+			}
+		}
 	}
 
 	return node != NULL;
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index dea17fd..32b4a16 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -158,25 +158,38 @@ static inline int compute_score(struct sock *sk, struct net *net,
 }
 
 struct sock *inet6_lookup_listener(struct net *net,
-		struct inet_hashinfo *hashinfo, const struct in6_addr *daddr,
+		struct inet_hashinfo *hashinfo, const struct in6_addr *saddr,
+		const __be16 sport, const struct in6_addr *daddr,
 		const unsigned short hnum, const int dif)
 {
 	struct sock *sk;
 	const struct hlist_nulls_node *node;
 	struct sock *result;
-	int score, hiscore;
+	int score, hiscore, matches = 0, reuseport = 0;
+	u32 phash = 0;
 	unsigned int hash = inet_lhashfn(net, hnum);
 	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 
 	rcu_read_lock();
 begin:
 	result = NULL;
-	hiscore = -1;
+	hiscore = 0;
 	sk_nulls_for_each(sk, node, &ilb->head) {
 		score = compute_score(sk, net, hnum, daddr, dif);
 		if (score > hiscore) {
 			hiscore = score;
 			result = sk;
+			reuseport = sk->sk_reuseport;
+			if (reuseport) {
+				phash = inet6_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);
 		}
 	}
 	/*
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 3701c3c..06087e5 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -834,7 +834,8 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 		 * no RST generated if md5 hash doesn't match.
 		 */
 		sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
-					   &tcp_hashinfo, &ipv6h->daddr,
+					   &tcp_hashinfo, &ipv6h->saddr,
+					   th->source, &ipv6h->daddr,
 					   ntohs(th->source), inet6_iif(skb));
 		if (!sk1)
 			return;
@@ -1598,6 +1599,7 @@ do_time_wait:
 		struct sock *sk2;
 
 		sk2 = inet6_lookup_listener(dev_net(skb->dev), &tcp_hashinfo,
+					    &ipv6_hdr(skb)->saddr, th->source,
 					    &ipv6_hdr(skb)->daddr,
 					    ntohs(th->dest), inet6_iif(skb));
 		if (sk2 != NULL) {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1afb635..cb5bf49 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -45,6 +45,7 @@
 #include <net/tcp_states.h>
 #include <net/ip6_checksum.h>
 #include <net/xfrm.h>
+#include <net/inet6_hashtables.h>
 
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
@@ -203,7 +204,8 @@ static struct sock *udp6_lib_lookup2(struct net *net,
 {
 	struct sock *sk, *result;
 	struct hlist_nulls_node *node;
-	int score, badness;
+	int score, badness, matches = 0, reuseport = 0;
+	u32 hash = 0;
 
 begin:
 	result = NULL;
@@ -214,8 +216,18 @@ begin:
 		if (score > badness) {
 			result = sk;
 			badness = score;
-			if (score == SCORE2_MAX)
+			reuseport = sk->sk_reuseport;
+			if (reuseport) {
+				hash = inet6_ehashfn(net, daddr, hnum,
+						     saddr, sport);
+				matches = 1;
+			} else if (score == SCORE2_MAX)
 				goto exact_match;
+		} else if (score == badness && reuseport) {
+			matches++;
+			if (((u64)hash * matches) >> 32 == 0)
+				result = sk;
+			hash = next_pseudo_random32(hash);
 		}
 	}
 	/*
@@ -249,7 +261,8 @@ struct sock *__udp6_lib_lookup(struct net *net,
 	unsigned short hnum = ntohs(dport);
 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
-	int score, badness;
+	int score, badness, matches = 0, reuseport = 0;
+	u32 hash = 0;
 
 	rcu_read_lock();
 	if (hslot->count > 10) {
@@ -284,6 +297,17 @@ begin:
 		if (score > badness) {
 			result = sk;
 			badness = score;
+			reuseport = sk->sk_reuseport;
+			if (reuseport) {
+				hash = inet6_ehashfn(net, daddr, hnum,
+						     saddr, sport);
+				matches = 1;
+			}
+		} else if (score == badness && reuseport) {
+			matches++;
+			if (((u64)hash * matches) >> 32 == 0)
+				result = sk;
+			hash = next_pseudo_random32(hash);
 		}
 	}
 	/*