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/if_inet6.h b/include/net/if_inet6.h
index 04977ee..fccc218 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -286,5 +286,21 @@
buf[9] = broadcast[9];
memcpy(buf + 10, addr->s6_addr + 6, 10);
}
+
+static inline int ipv6_ipgre_mc_map(const struct in6_addr *addr,
+ const unsigned char *broadcast, char *buf)
+{
+ if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) {
+ memcpy(buf, broadcast, 4);
+ } else {
+ /* v4mapped? */
+ if ((addr->s6_addr32[0] | addr->s6_addr32[1] |
+ (addr->s6_addr32[2] ^ htonl(0x0000ffff))) != 0)
+ return -EINVAL;
+ memcpy(buf, &addr->s6_addr32[3], 4);
+ }
+ return 0;
+}
+
#endif
#endif