ipv6: Add helper inet6_csk_update_pmtu().

This is the ipv6 version of inet_csk_update_pmtu().

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

3 files changed, 43 insertions, 78 deletions

diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 090c0800ce03..3ee0342e1cec 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -145,39 +145,12 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
                         goto out;
 
-                /* icmp should have updated the destination cache entry */
-                dst = __sk_dst_check(sk, np->dst_cookie);
-                if (dst == NULL) {
-                        struct inet_sock *inet = inet_sk(sk);
-                        struct flowi6 fl6;
-
-                        /* BUGGG_FUTURE: Again, it is not clear how
-                           to handle rthdr case. Ignore this complexity
-                           for now.
-                         */
-                        memset(&fl6, 0, sizeof(fl6));
-                        fl6.flowi6_proto = IPPROTO_DCCP;
-                        fl6.daddr = np->daddr;
-                        fl6.saddr = np->saddr;
-                        fl6.flowi6_oif = sk->sk_bound_dev_if;
-                        fl6.fl6_dport = inet->inet_dport;
-                        fl6.fl6_sport = inet->inet_sport;
-                        security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
-
-                        dst = ip6_dst_lookup_flow(sk, &fl6, NULL, false);
-                        if (IS_ERR(dst)) {
-                                sk->sk_err_soft = -PTR_ERR(dst);
-                                goto out;
-                        }
-                } else
-                        dst_hold(dst);
-
-                dst->ops->update_pmtu(dst, ntohl(info));
+                dst = inet6_csk_update_pmtu(sk, ntohl(info));
+                if (!dst)
+                        goto out;
 
-                if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
+                if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst))
                         dccp_sync_mss(sk, dst_mtu(dst));
-                } /* else let the usual retransmit timer handle it */
-                dst_release(dst);
                 goto out;
         }
 
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index bceb14450a1d..62539a4b2dc7 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -203,15 +203,13 @@ struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
         return dst;
 }
 
-int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
+static struct dst_entry *inet6_csk_route_socket(struct sock *sk)
 {
-        struct sock *sk = skb->sk;
         struct inet_sock *inet = inet_sk(sk);
         struct ipv6_pinfo *np = inet6_sk(sk);
-        struct flowi6 fl6;
-        struct dst_entry *dst;
         struct in6_addr *final_p, final;
-        int res;
+        struct dst_entry *dst;
+        struct flowi6 fl6;
 
         memset(&fl6, 0, sizeof(fl6));
         fl6.flowi6_proto = sk->sk_protocol;
@@ -228,18 +226,29 @@ int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
         final_p = fl6_update_dst(&fl6, np->opt, &final);
 
         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
-
-        if (dst == NULL) {
+        if (!dst) {
                 dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
 
-                if (IS_ERR(dst)) {
-                        sk->sk_err_soft = -PTR_ERR(dst);
-                        sk->sk_route_caps = 0;
-                        kfree_skb(skb);
-                        return PTR_ERR(dst);
-                }
+                if (!IS_ERR(dst))
+                        __inet6_csk_dst_store(sk, dst, NULL, NULL);
+        }
+        return dst;
+}
 
-                __inet6_csk_dst_store(sk, dst, NULL, NULL);
+int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
+{
+        struct sock *sk = skb->sk;
+        struct ipv6_pinfo *np = inet6_sk(sk);
+        struct flowi6 fl6;
+        struct dst_entry *dst;
+        int res;
+
+        dst = inet6_csk_route_socket(sk);
+        if (IS_ERR(dst)) {
+                sk->sk_err_soft = -PTR_ERR(dst);
+                sk->sk_route_caps = 0;
+                kfree_skb(skb);
+                return PTR_ERR(dst);
         }
 
         rcu_read_lock();
@@ -253,3 +262,15 @@ int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
         return res;
 }
 EXPORT_SYMBOL_GPL(inet6_csk_xmit);
+
+struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu)
+{
+        struct dst_entry *dst = inet6_csk_route_socket(sk);
+
+        if (IS_ERR(dst))
+                return NULL;
+        dst->ops->update_pmtu(dst, mtu);
+
+        return inet6_csk_route_socket(sk);
+}
+EXPORT_SYMBOL_GPL(inet6_csk_update_pmtu);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 3071f377145c..ecdf241cad02 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -378,43 +378,14 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
                         goto out;
 
-                /* icmp should have updated the destination cache entry */
-                dst = __sk_dst_check(sk, np->dst_cookie);
-
-                if (dst == NULL) {
-                        struct inet_sock *inet = inet_sk(sk);
-                        struct flowi6 fl6;
-
-                        /* BUGGG_FUTURE: Again, it is not clear how
-                           to handle rthdr case. Ignore this complexity
-                           for now.
-                         */
-                        memset(&fl6, 0, sizeof(fl6));
-                        fl6.flowi6_proto = IPPROTO_TCP;
-                        fl6.daddr = np->daddr;
-                        fl6.saddr = np->saddr;
-                        fl6.flowi6_oif = sk->sk_bound_dev_if;
-                        fl6.flowi6_mark = sk->sk_mark;
-                        fl6.fl6_dport = inet->inet_dport;
-                        fl6.fl6_sport = inet->inet_sport;
-                        security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
-
-                        dst = ip6_dst_lookup_flow(sk, &fl6, NULL, false);
-                        if (IS_ERR(dst)) {
-                                sk->sk_err_soft = -PTR_ERR(dst);
-                                goto out;
-                        }
-
-                } else
-                        dst_hold(dst);
-
-                dst->ops->update_pmtu(dst, ntohl(info));
+                dst = inet6_csk_update_pmtu(sk, ntohl(info));
+                if (!dst)
+                        goto out;
 
                 if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
                         tcp_sync_mss(sk, dst_mtu(dst));
                         tcp_simple_retransmit(sk);
-                } /* else let the usual retransmit timer handle it */
-                dst_release(dst);
+                }
                 goto out;
         }