1 files changed, 43 insertions, 1 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 321f175055bf..3a571d6614f9 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -80,6 +80,9 @@
 
 #include <asm/uaccess.h>
 
+static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
+                                         union sctp_addr *s2);
+
 /* Event handler for inet6 address addition/deletion events.
  * The sctp_local_addr_list needs to be protocted by a spin lock since
  * multiple notifiers (say IPv4 and IPv6) may be running at the same
@@ -244,8 +247,14 @@ static struct dst_entry *sctp_v6_get_dst(struct sctp_association *asoc,
                                          union sctp_addr *daddr,
                                          union sctp_addr *saddr)
 {
-        struct dst_entry *dst;
+        struct dst_entry *dst = NULL;
         struct flowi6 fl6;
+        struct sctp_bind_addr *bp;
+        struct sctp_sockaddr_entry *laddr;
+        union sctp_addr *baddr = NULL;
+        __u8 matchlen = 0;
+        __u8 bmatchlen;
+        sctp_scope_t scope;
 
         memset(&fl6, 0, sizeof(fl6));
         ipv6_addr_copy(&fl6.daddr, &daddr->v6.sin6_addr);
@@ -261,6 +270,39 @@ static struct dst_entry *sctp_v6_get_dst(struct sctp_association *asoc,
         }
 
         dst = ip6_route_output(&init_net, NULL, &fl6);
+        if (!asoc || saddr)
+                goto out;
+
+        if (dst->error) {
+                dst_release(dst);
+                dst = NULL;
+                bp = &asoc->base.bind_addr;
+                scope = sctp_scope(daddr);
+                /* Walk through the bind address list and try to get a dst that
+                 * matches a bind address as the source address.
+                 */
+                rcu_read_lock();
+                list_for_each_entry_rcu(laddr, &bp->address_list, list) {
+                        if (!laddr->valid)
+                                continue;
+                        if ((laddr->state == SCTP_ADDR_SRC) &&
+                            (laddr->a.sa.sa_family == AF_INET6) &&
+                            (scope <= sctp_scope(&laddr->a))) {
+                                bmatchlen = sctp_v6_addr_match_len(daddr,
+                                                                   &laddr->a);
+                                if (!baddr || (matchlen < bmatchlen)) {
+                                        baddr = &laddr->a;
+                                        matchlen = bmatchlen;
+                                }
+                        }
+                }
+                rcu_read_unlock();
+                if (baddr) {
+                        ipv6_addr_copy(&fl6.saddr, &baddr->v6.sin6_addr);
+                        dst = ip6_route_output(&init_net, NULL, &fl6);
+                }
+        }
+out:
         if (!dst->error) {
                 struct rt6_info *rt;
                 rt = (struct rt6_info *)dst;