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, 21 insertions, 36 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1d0ab557090..e59a31c48ba 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -255,18 +255,10 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 
 	security_sk_classify_flow(sk, &fl);
 
-	err = ip6_dst_lookup(sk, &dst, &fl);
-	if (err)
+	dst = ip6_dst_lookup_flow(sk, &fl, final_p, true);
+	if (IS_ERR(dst)) {
+		err = PTR_ERR(dst);
 		goto failure;
-	if (final_p)
-		ipv6_addr_copy(&fl.fl6_dst, final_p);
-
-	err = __xfrm_lookup(sock_net(sk), &dst, &fl, sk, XFRM_LOOKUP_WAIT);
-	if (err < 0) {
-		if (err == -EREMOTE)
-			err = ip6_dst_blackhole(sk, &dst, &fl);
-		if (err < 0)
-			goto failure;
 	}
 
 	if (saddr == NULL) {
@@ -385,7 +377,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	np = inet6_sk(sk);
 
 	if (type == ICMPV6_PKT_TOOBIG) {
-		struct dst_entry *dst = NULL;
+		struct dst_entry *dst;
 
 		if (sock_owned_by_user(sk))
 			goto out;
@@ -413,13 +405,9 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			fl.fl_ip_sport = inet->inet_sport;
 			security_skb_classify_flow(skb, &fl);
 
-			if ((err = ip6_dst_lookup(sk, &dst, &fl))) {
-				sk->sk_err_soft = -err;
-				goto out;
-			}
-
-			if ((err = xfrm_lookup(net, &dst, &fl, sk, 0)) < 0) {
-				sk->sk_err_soft = -err;
+			dst = ip6_dst_lookup_flow(sk, &fl, NULL, false);
+			if (IS_ERR(dst)) {
+				sk->sk_err_soft = -PTR_ERR(dst);
 				goto out;
 			}
 
@@ -496,7 +484,7 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
 	struct in6_addr * final_p, final;
 	struct flowi fl;
 	struct dst_entry *dst;
-	int err = -1;
+	int err;
 
 	memset(&fl, 0, sizeof(fl));
 	fl.proto = IPPROTO_TCP;
@@ -512,15 +500,13 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
 	opt = np->opt;
 	final_p = fl6_update_dst(&fl, 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)) {
+		err = PTR_ERR(dst);
 		goto done;
-	if (final_p)
-		ipv6_addr_copy(&fl.fl6_dst, final_p);
-	if ((err = xfrm_lookup(sock_net(sk), &dst, &fl, sk, 0)) < 0)
-		goto done;
-
+	}
 	skb = tcp_make_synack(sk, dst, req, rvp);
+	err = -ENOMEM;
 	if (skb) {
 		__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
 
@@ -1079,15 +1065,14 @@ static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
 	 * Underlying function will use this to retrieve the network
 	 * namespace
 	 */
-	if (!ip6_dst_lookup(ctl_sk, &dst, &fl)) {
-		if (xfrm_lookup(net, &dst, &fl, NULL, 0) >= 0) {
-			skb_dst_set(buff, dst);
-			ip6_xmit(ctl_sk, buff, &fl, NULL);
-			TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
-			if (rst)
-				TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
-			return;
-		}
+	dst = ip6_dst_lookup_flow(ctl_sk, &fl, NULL, false);
+	if (!IS_ERR(dst)) {
+		skb_dst_set(buff, dst);
+		ip6_xmit(ctl_sk, buff, &fl, NULL);
+		TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
+		if (rst)
+			TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
+		return;
 	}
 
 	kfree_skb(buff);