gre: better support for ICMP messages for gre+ipv6
ipgre_err() can call ip6_err_gen_icmpv6_unreach() for proper
support of ipv4+gre+icmp+ipv6+... frames, used for example
by traceroute/mtr.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 9222678..a5e7035 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -157,6 +157,7 @@
__be16 proto;
__be32 key;
__be32 seq;
+ int hdr_len;
};
#define PACKET_RCVD 0
diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 4c39f4f..c4c3e43 100644
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -117,6 +117,7 @@
if ((*(u8 *)options & 0xF0) != 0x40)
hdr_len += 4;
}
+ tpi->hdr_len = hdr_len;
return hdr_len;
}
EXPORT_SYMBOL(gre_parse_header);
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 0f8ca3f..ab4cff8 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -187,6 +187,12 @@
if (!t)
return;
+#if IS_ENABLED(CONFIG_IPV6)
+ if (tpi->proto == htons(ETH_P_IPV6) &&
+ !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len, type))
+ return;
+#endif
+
if (t->parms.iph.daddr == 0 ||
ipv4_is_multicast(t->parms.iph.daddr))
return;