ipv6: Use rt6i_idev index for echo replies to a local address

Tariq repored local pings to linklocal address is failing:
$ ifconfig ens8
ens8: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 11.141.16.6  netmask 255.255.0.0  broadcast 11.141.255.255
        inet6 fe80::7efe:90ff:fecb:7502  prefixlen 64  scopeid 0x20<link>
        ether 7c:fe:90:cb:75:02  txqueuelen 1000  (Ethernet)
        RX packets 12  bytes 1164 (1.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 30  bytes 2484 (2.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

$  /bin/ping6 -c 3 fe80::7efe:90ff:fecb:7502%ens8
PING fe80::7efe:90ff:fecb:7502%ens8(fe80::7efe:90ff:fecb:7502) 56 data bytes

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

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 882bc3c..ee96f40 100644 (file)
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -164,6 +164,16 @@ void rt6_mtu_change(struct net_device *dev, unsigned int mtu);
 void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
 void rt6_clean_tohost(struct net *net, struct in6_addr *gateway);
 
+static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb)
+{
+       const struct dst_entry *dst = skb_dst(skb);
+       const struct rt6_info *rt6 = NULL;
+
+       if (dst)
+               rt6 = container_of(dst, struct rt6_info, dst);
+
+       return rt6;
+}
 
 /*
  *     Store a destination cache entry in a socket

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index dd7608c..5acb544 100644 (file)
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -399,6 +399,24 @@ relookup_failed:
        return ERR_PTR(err);
 }
 
+static int icmp6_iif(const struct sk_buff *skb)
+{
+       int iif = skb->dev->ifindex;
+
+       /* for local traffic to local address, skb dev is the loopback
+        * device. Check if there is a dst attached to the skb and if so
+        * get the real device index.
+        */
+       if (unlikely(iif == LOOPBACK_IFINDEX)) {
+               const struct rt6_info *rt6 = skb_rt6_info(skb);
+
+               if (rt6)
+                       iif = rt6->rt6i_idev->dev->ifindex;
+       }
+
+       return iif;
+}
+
 /*
  *     Send an ICMP message in response to a packet in error
  */
@@ -460,18 +478,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
         */
 
        if (__ipv6_addr_needs_scope_id(addr_type)) {
-               iif = skb->dev->ifindex;
-
-               /* for local packets, get the real device index */
-               if (iif == LOOPBACK_IFINDEX) {
-                       dst = skb_dst(skb);
-                       if (dst) {
-                               struct rt6_info *rt;
-
-                               rt = container_of(dst, struct rt6_info, dst);
-                               iif = rt->rt6i_idev->dev->ifindex;
-                       }
-               }
+               iif = icmp6_iif(skb);
        } else {
                dst = skb_dst(skb);
                iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev);
@@ -694,7 +701,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
        fl6.daddr = ipv6_hdr(skb)->saddr;
        if (saddr)
                fl6.saddr = *saddr;
-       fl6.flowi6_oif = skb->dev->ifindex;
+       fl6.flowi6_oif = icmp6_iif(skb);
        fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
        fl6.flowi6_mark = mark;
        fl6.flowi6_uid = sock_net_uid(net, NULL);