ipv6: Consolidate route lookup sequences.

Route lookups follow a general pattern in the ipv6 code wherein
we first find the non-IPSEC route, potentially override the
flow destination address due to ipv6 options settings, and then
finally make an IPSEC search using either xfrm_lookup() or
__xfrm_lookup().

__xfrm_lookup() is used when we want to generate a blackhole route
if the key manager needs to resolve the IPSEC rules (in this case
-EREMOTE is returned and the original 'dst' is left unchanged).

Otherwise plain xfrm_lookup() is used and when asynchronous IPSEC
resolution is necessary, we simply fail the lookup completely.

All of these cases are encapsulated into two routines,
ip6_dst_lookup_flow and ip6_sk_dst_lookup_flow.  The latter of which
handles unconnected UDP datagram sockets.

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

1 files changed, 5 insertions, 12 deletions

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 3194aa909872..a88b2e9d25f1 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -644,9 +644,8 @@ EXPORT_SYMBOL(inet6_unregister_protosw);
 
 int inet6_sk_rebuild_header(struct sock *sk)
 {
-        int err;
-        struct dst_entry *dst;
         struct ipv6_pinfo *np = inet6_sk(sk);
+        struct dst_entry *dst;
 
         dst = __sk_dst_check(sk, np->dst_cookie);
 
@@ -668,17 +667,11 @@ int inet6_sk_rebuild_header(struct sock *sk)
 
                 final_p = fl6_update_dst(&fl, np->opt, &final);
 
-                err = ip6_dst_lookup(sk, &dst, &fl);
-                if (err) {
+                dst = ip6_dst_lookup_flow(sk, &fl, final_p, false);
+                if (IS_ERR(dst)) {
                         sk->sk_route_caps = 0;
-                        return err;
-                }
-                if (final_p)
-                        ipv6_addr_copy(&fl.fl6_dst, final_p);
-
-                if ((err = xfrm_lookup(sock_net(sk), &dst, &fl, sk, 0)) < 0) {
-                        sk->sk_err_soft = -err;
-                        return err;
+                        sk->sk_err_soft = -PTR_ERR(dst);
+                        return PTR_ERR(dst);
                 }
 
                 __ip6_dst_store(sk, dst, NULL, NULL);