ipv6: Implement IPV6_UNICAST_IF socket option.

The IPV6_UNICAST_IF feature is the IPv6 compliment to IP_UNICAST_IF.

Signed-off-by: Erich E. Hoover <ehoover@mines.edu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 44 insertions, 1 deletions

diff --git a/include/linux/in6.h b/include/linux/in6.h
index 097a34b55560..5c83d9e3eb8f 100644
--- a/include/linux/in6.h
+++ b/include/linux/in6.h
@@ -271,6 +271,7 @@ struct in6_flowlabel_req {
 #define IPV6_ORIGDSTADDR        74
 #define IPV6_RECVORIGDSTADDR    IPV6_ORIGDSTADDR
 #define IPV6_TRANSPARENT        75
+#define IPV6_UNICAST_IF         76
 
 /*
  * Multicast Routing:
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 6318268dcaf5..743a16a41040 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -324,6 +324,7 @@ struct ipv6_pinfo {
                                 __unused_2:6;
         __s16                   mcast_hops:9;
 #endif
+        int                     ucast_oif;
         int                     mcast_oif;
 
         /* pktoption flags */
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 01d46bff63c3..af88934e4d79 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -468,6 +468,8 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 
         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
                 fl6.flowi6_oif = np->mcast_oif;
+        else if (!fl6.flowi6_oif)
+                fl6.flowi6_oif = np->ucast_oif;
 
         dst = icmpv6_route_lookup(net, skb, sk, &fl6);
         if (IS_ERR(dst))
@@ -553,6 +555,8 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
 
         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
                 fl6.flowi6_oif = np->mcast_oif;
+        else if (!fl6.flowi6_oif)
+                fl6.flowi6_oif = np->ucast_oif;
 
         err = ip6_dst_lookup(sk, &dst, &fl6);
         if (err)
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 18a2719003c3..6d6b65fdaa1a 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -516,6 +516,36 @@ done:
                 retv = 0;
                 break;
 
+        case IPV6_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) {
+                        np->ucast_oif = 0;
+                        retv = 0;
+                        break;
+                }
+
+                dev = dev_get_by_index(net, ifindex);
+                retv = -EADDRNOTAVAIL;
+                if (!dev)
+                        break;
+                dev_put(dev);
+
+                retv = -EINVAL;
+                if (sk->sk_bound_dev_if)
+                        break;
+
+                np->ucast_oif = ifindex;
+                retv = 0;
+                break;
+        }
+
         case IPV6_MULTICAST_IF:
                 if (sk->sk_type == SOCK_STREAM)
                         break;
@@ -1160,6 +1190,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
                 val = np->mcast_oif;
                 break;
 
+        case IPV6_UNICAST_IF:
+                val = (__force int)htonl((__u32) np->ucast_oif);
+                break;
+
         case IPV6_MTU_DISCOVER:
                 val = np->pmtudisc;
                 break;
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index d02f7e4dd611..5bddea778840 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -856,6 +856,8 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 
         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
                 fl6.flowi6_oif = np->mcast_oif;
+        else if (!fl6.flowi6_oif)
+                fl6.flowi6_oif = np->ucast_oif;
         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 4f96b5c63685..8aebf8f90436 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1130,7 +1130,8 @@ do_udp_sendmsg:
         if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) {
                 fl6.flowi6_oif = np->mcast_oif;
                 connected = 0;
-        }
+        } else if (!fl6.flowi6_oif)
+                fl6.flowi6_oif = np->ucast_oif;
 
         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));