ipv6: Make icmp route lookup code a bit clearer.
The route lookup code in icmpv6_send() is slightly tricky as a result of
having to handle all of the requirements of RFC 4301 host relookups.
Pull the route resolution into a seperate function, so that the error
handling and route reference counting is hopefully easier to see and
contained wholly within this new routine.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index a31d91b..e332bae 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -300,6 +300,70 @@
static inline void mip6_addr_swap(struct sk_buff *skb) {}
#endif
+static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,
+ struct sock *sk, struct flowi *fl)
+{
+ struct dst_entry *dst, *dst2;
+ struct flowi fl2;
+ int err;
+
+ err = ip6_dst_lookup(sk, &dst, fl);
+ if (err)
+ return ERR_PTR(err);
+
+ /*
+ * We won't send icmp if the destination is known
+ * anycast.
+ */
+ if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
+ LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
+ dst_release(dst);
+ return ERR_PTR(-EINVAL);
+ }
+
+ /* No need to clone since we're just using its address. */
+ dst2 = dst;
+
+ err = xfrm_lookup(net, &dst, fl, sk, 0);
+ switch (err) {
+ case 0:
+ if (dst != dst2)
+ return dst;
+ break;
+ case -EPERM:
+ dst = NULL;
+ break;
+ default:
+ return ERR_PTR(err);
+ }
+
+ err = xfrm_decode_session_reverse(skb, &fl2, AF_INET6);
+ if (err)
+ goto relookup_failed;
+
+ err = ip6_dst_lookup(sk, &dst2, &fl2);
+ if (err)
+ goto relookup_failed;
+
+ err = xfrm_lookup(net, &dst2, &fl2, sk, XFRM_LOOKUP_ICMP);
+ switch (err) {
+ case 0:
+ dst_release(dst);
+ dst = dst2;
+ break;
+ case -EPERM:
+ dst_release(dst);
+ return ERR_PTR(err);
+ default:
+ goto relookup_failed;
+ }
+
+relookup_failed:
+ if (dst)
+ return dst;
+ return ERR_PTR(err);
+}
+
/*
* Send an ICMP message in response to a packet in error
*/
@@ -312,10 +376,8 @@
struct ipv6_pinfo *np;
struct in6_addr *saddr = NULL;
struct dst_entry *dst;
- struct dst_entry *dst2;
struct icmp6hdr tmp_hdr;
struct flowi fl;
- struct flowi fl2;
struct icmpv6_msg msg;
int iif = 0;
int addr_type = 0;
@@ -408,57 +470,10 @@
if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
fl.oif = np->mcast_oif;
- err = ip6_dst_lookup(sk, &dst, &fl);
- if (err)
+ dst = icmpv6_route_lookup(net, skb, sk, &fl);
+ if (IS_ERR(dst))
goto out;
- /*
- * We won't send icmp if the destination is known
- * anycast.
- */
- if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
- LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
- goto out_dst_release;
- }
-
- /* No need to clone since we're just using its address. */
- dst2 = dst;
-
- err = xfrm_lookup(net, &dst, &fl, sk, 0);
- switch (err) {
- case 0:
- if (dst != dst2)
- goto route_done;
- break;
- case -EPERM:
- dst = NULL;
- break;
- default:
- goto out;
- }
-
- if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6))
- goto relookup_failed;
-
- if (ip6_dst_lookup(sk, &dst2, &fl2))
- goto relookup_failed;
-
- err = xfrm_lookup(net, &dst2, &fl2, sk, XFRM_LOOKUP_ICMP);
- switch (err) {
- case 0:
- dst_release(dst);
- dst = dst2;
- break;
- case -EPERM:
- goto out_dst_release;
- default:
-relookup_failed:
- if (!dst)
- goto out;
- break;
- }
-
-route_done:
if (ipv6_addr_is_multicast(&fl.fl6_dst))
hlimit = np->mcast_hops;
else