ipv6: translate ICMP_TIME_EXCEEDED to ICMPV6_TIME_EXCEED

For better traceroute/mtr support for SIT and GRE tunnels,
we translate IPV4 ICMP ICMP_TIME_EXCEEDED to ICMPV6_TIME_EXCEED

We also have to translate the IPv4 source IP address of ICMP
message to IPv6 v4mapped.

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

2 files changed, 12 insertions, 6 deletions

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 07bc63c23712..867aebc34248 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -564,8 +564,9 @@ void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
  *  Either an IPv4 header for SIT encap
  *         an IPv4 header + GRE header for GRE encap
  */
-int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs)
+int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type)
 {
+        struct in6_addr temp_saddr;
         struct rt6_info *rt;
         struct sk_buff *skb2;
 
@@ -586,8 +587,13 @@ int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs)
         if (rt && rt->dst.dev)
                 skb2->dev = rt->dst.dev;
 
-        icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
-
+        ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
+        if (type == ICMP_TIME_EXCEEDED)
+                icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
+                           0, &temp_saddr);
+        else
+                icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
+                           0, &temp_saddr);
         if (rt)
                 ip6_rt_put(rt);
 
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 78e84d6793ee..d7a36114eb50 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -535,11 +535,11 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
                 goto out;
         }
 
-        if (t->parms.iph.daddr == 0)
+        err = 0;
+        if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type))
                 goto out;
 
-        err = 0;
-        if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4))
+        if (t->parms.iph.daddr == 0)
                 goto out;
 
         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)