net: gre: provide multicast mappings for ipv4 and ipv6
My commit 6d55cb91a0020ac0 (gre: fix hard header destination
address checking) broke multicast.
The reason is that ip_gre used to get ipgre_header() calls with
zero destination if we have NOARP or multicast destination. Instead
the actual target was decided at ipgre_tunnel_xmit() time based on
per-protocol dissection.
Instead of allowing the "abuse" of ->header() calls with invalid
destination, this creates multicast mappings for ip_gre. This also
fixes "ip neigh show nud noarp" to display the proper multicast
mappings used by the gre device.
Reported-by: Doug Kehn <rdkehn@yahoo.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Doug Kehn <rdkehn@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip.h b/include/net/ip.h
index a4f6311..7c41658 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -339,6 +339,14 @@
buf[16] = addr & 0x0f;
}
+static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
+{
+ if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
+ memcpy(buf, broadcast, 4);
+ else
+ memcpy(buf, &naddr, sizeof(naddr));
+}
+
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#include <linux/ipv6.h>
#endif