4 files changed, 39 insertions, 3 deletions

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 8aa87c1..9125529 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -469,6 +469,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 			     (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) |
 			     (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT) |
 			     (1<<IP_MINTTL) | (1<<IP_NODEFRAG))) ||
+	    optname == IP_UNICAST_IF ||
 	    optname == IP_MULTICAST_TTL ||
 	    optname == IP_MULTICAST_ALL ||
 	    optname == IP_MULTICAST_LOOP ||
@@ -628,6 +629,35 @@ static int do_ip_setsockopt(struct sock *sk, int level,
 			goto e_inval;
 		inet->mc_loop = !!val;
 		break;
+	case IP_UNICAST_IF:
+	{
+		struct net_device *dev = NULL;
+		int ifindex;
+
+		if (optlen != sizeof(int))
+			goto e_inval;
+
+		ifindex = (__force int)ntohl((__force __be32)val);
+		if (ifindex == 0) {
+			inet->uc_index = 0;
+			err = 0;
+			break;
+		}
+
+		dev = dev_get_by_index(sock_net(sk), ifindex);
+		err = -EADDRNOTAVAIL;
+		if (!dev)
+			break;
+		dev_put(dev);
+
+		err = -EINVAL;
+		if (sk->sk_bound_dev_if)
+			break;
+
+		inet->uc_index = ifindex;
+		err = 0;
+		break;
+	}
 	case IP_MULTICAST_IF:
 	{
 		struct ip_mreqn mreq;
@@ -1178,6 +1208,9 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
 	case IP_MULTICAST_LOOP:
 		val = inet->mc_loop;
 		break;
+	case IP_UNICAST_IF:
+		val = (__force int)htonl((__u32) inet->uc_index);
+		break;
 	case IP_MULTICAST_IF:
 	{
 		struct in_addr addr;
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index aea5a19..cfc82cf 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -556,7 +556,8 @@ static int ping_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 			ipc.oif = inet->mc_index;
 		if (!saddr)
 			saddr = inet->mc_addr;
-	}
+	} else if (!ipc.oif)
+		ipc.oif = inet->uc_index;
 
 	flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 			   RT_SCOPE_UNIVERSE, sk->sk_protocol,
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 3ccda5a..ab46630 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -563,7 +563,8 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 			ipc.oif = inet->mc_index;
 		if (!saddr)
 			saddr = inet->mc_addr;
-	}
+	} else if (!ipc.oif)
+		ipc.oif = inet->uc_index;
 
 	flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 			   RT_SCOPE_UNIVERSE,
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5d075b5..cd99f1a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -917,7 +917,8 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 		if (!saddr)
 			saddr = inet->mc_addr;
 		connected = 0;
-	}
+	} else if (!ipc.oif)
+		ipc.oif = inet->uc_index;
 
 	if (connected)
 		rt = (struct rtable *)sk_dst_check(sk, 0);