net/ipv6: Fix linklocal to global address with VRF

Example setup:
    host: ip -6 addr add dev eth1 2001:db8:104::4
           where eth1 is enslaved to a VRF

    switch: ip -6 ro add 2001:db8:104::4/128 dev br1
            where br1 only has an LLA

           ping6 2001:db8:104::4
           ssh   2001:db8:104::4

(NOTE: UDP works fine if the PKTINFO has the address set to the global
address and ifindex is set to the index of eth1 with a destination an
LLA).

For ICMP, icmp6_iif needs to be updated to check if skb->dev is an
L3 master. If it is then return the ifindex from rt6i_idev similar
to what is done for loopback.

For TCP, restore the original tcp_v6_iif definition which is needed in
most places and add a new tcp_v6_iif_l3_slave that considers the
l3_slave variability. This latter check is only needed for socket
lookups.

Fixes: 9ff74384600a ("net: vrf: Handle ipv6 multicast and link-local addresses")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 25116ec..cd3ecda 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -840,6 +840,11 @@ static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb)
  * as TCP moves IP6CB into a different location in skb->cb[]
  */
 static inline int tcp_v6_iif(const struct sk_buff *skb)
+{
+       return TCP_SKB_CB(skb)->header.h6.iif;
+}
+
+static inline int tcp_v6_iif_l3_slave(const struct sk_buff *skb)
 {
        bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);
 

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index be491bf..ef2505a 100644 (file)
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -402,9 +402,10 @@ static int icmp6_iif(const struct sk_buff *skb)
 
        /* 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.
+        * get the real device index. Same is needed for replies to a link
+        * local address on a device enslaved to an L3 master device
         */
-       if (unlikely(iif == LOOPBACK_IFINDEX)) {
+       if (unlikely(iif == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
                const struct rt6_info *rt6 = skb_rt6_info(skb);
 
                if (rt6)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7efa9fd..03e6b7a 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -938,7 +938,8 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
                                           &tcp_hashinfo, NULL, 0,
                                           &ipv6h->saddr,
                                           th->source, &ipv6h->daddr,
-                                          ntohs(th->source), tcp_v6_iif(skb),
+                                          ntohs(th->source),
+                                          tcp_v6_iif_l3_slave(skb),
                                           tcp_v6_sdif(skb));
                if (!sk1)
                        goto out;
@@ -1609,7 +1610,8 @@ do_time_wait:
                                            skb, __tcp_hdrlen(th),
                                            &ipv6_hdr(skb)->saddr, th->source,
                                            &ipv6_hdr(skb)->daddr,
-                                           ntohs(th->dest), tcp_v6_iif(skb),
+                                           ntohs(th->dest),
+                                           tcp_v6_iif_l3_slave(skb),
                                            sdif);
                if (sk2) {
                        struct inet_timewait_sock *tw = inet_twsk(sk);