ipv4: fix TCP early demux

commit 92101b3b2e317 (ipv4: Prepare for change of rt->rt_iif encoding.)
invalidated TCP early demux, because rx_dst_ifindex is not properly
initialized and checked.

Also remove the use of inet_iif(skb) in favor or skb->skb_iif

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 8 insertions, 8 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3e07a64ca44e..aa659e825054 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5603,6 +5603,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 
         if (skb != NULL) {
                 sk->sk_rx_dst = dst_clone(skb_dst(skb));
+                inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
                 security_inet_conn_established(sk, skb);
         }
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b6b07c93924c..2fbd9921253f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1620,17 +1620,15 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
                 sock_rps_save_rxhash(sk, skb);
                 if (sk->sk_rx_dst) {
                         struct dst_entry *dst = sk->sk_rx_dst;
-                        if (dst->ops->check(dst, 0) == NULL) {
+                        if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
+                            dst->ops->check(dst, 0) == NULL) {
                                 dst_release(dst);
                                 sk->sk_rx_dst = NULL;
                         }
                 }
                 if (unlikely(sk->sk_rx_dst == NULL)) {
-                        struct inet_sock *icsk = inet_sk(sk);
-                        struct rtable *rt = skb_rtable(skb);
-
-                        sk->sk_rx_dst = dst_clone(&rt->dst);
-                        icsk->rx_dst_ifindex = inet_iif(skb);
+                        sk->sk_rx_dst = dst_clone(skb_dst(skb));
+                        inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
                 }
                 if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
                         rsk = sk;
@@ -1709,11 +1707,11 @@ void tcp_v4_early_demux(struct sk_buff *skb)
                 skb->destructor = sock_edemux;
                 if (sk->sk_state != TCP_TIME_WAIT) {
                         struct dst_entry *dst = sk->sk_rx_dst;
-                        struct inet_sock *icsk = inet_sk(sk);
+
                         if (dst)
                                 dst = dst_check(dst, 0);
                         if (dst &&
-                            icsk->rx_dst_ifindex == skb->skb_iif)
+                            inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
                                 skb_dst_set_noref(skb, dst);
                 }
         }
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 5912ac3fd240..3f1cc2028edd 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -388,6 +388,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
                 struct tcp_cookie_values *oldcvp = oldtp->cookie_values;
 
                 newsk->sk_rx_dst = dst_clone(skb_dst(skb));
+                inet_sk(newsk)->rx_dst_ifindex = skb->skb_iif;
 
                 /* TCP Cookie Transactions require space for the cookie pair,
                  * as it differs for each connection.  There is no need to