1 files changed, 11 insertions, 7 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 10b7c0478830..5ca56cee2dae 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -726,7 +726,7 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 #endif
 
 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
-                                 u32 tsval, u32 tsecr,
+                                 u32 tsval, u32 tsecr, int oif,
                                  struct tcp_md5sig_key *key, int rst, u8 tclass,
                                  u32 label)
 {
@@ -798,8 +798,10 @@ static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
         __tcp_v6_send_check(buff, &fl6.saddr, &fl6.daddr);
 
         fl6.flowi6_proto = IPPROTO_TCP;
-        if (ipv6_addr_type(&fl6.daddr) & IPV6_ADDR_LINKLOCAL)
+        if (rt6_need_strict(&fl6.daddr) || !oif)
                 fl6.flowi6_oif = inet6_iif(skb);
+        else
+                fl6.flowi6_oif = oif;
         fl6.fl6_dport = t1->dest;
         fl6.fl6_sport = t1->source;
         security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
@@ -833,6 +835,7 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
         int genhash;
         struct sock *sk1 = NULL;
 #endif
+        int oif;
 
         if (th->rst)
                 return;
@@ -876,7 +879,8 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
                 ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
                           (th->doff << 2);
 
-        tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, key, 1, 0, 0);
+        oif = sk ? sk->sk_bound_dev_if : 0;
+        tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
 
 #ifdef CONFIG_TCP_MD5SIG
 release_sk1:
@@ -888,11 +892,11 @@ release_sk1:
 }
 
 static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
-                            u32 win, u32 tsval, u32 tsecr,
+                            u32 win, u32 tsval, u32 tsecr, int oif,
                             struct tcp_md5sig_key *key, u8 tclass,
                             u32 label)
 {
-        tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, key, 0, tclass,
+        tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, oif, key, 0, tclass,
                              label);
 }
 
@@ -904,7 +908,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
         tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                         tcp_time_stamp + tcptw->tw_ts_offset,
-                        tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
+                        tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
                         tw->tw_tclass, (tw->tw_flowlabel << 12));
 
         inet_twsk_put(tw);
@@ -914,7 +918,7 @@ static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
                                   struct request_sock *req)
 {
         tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1,
-                        req->rcv_wnd, tcp_time_stamp, req->ts_recent,
+                        req->rcv_wnd, tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if,
                         tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
                         0, 0);
 }