From 93ca3bb5df9bc8b2c60485e1cc6507c3d7c8e1fa Mon Sep 17 00:00:00 2001
From: =?utf8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi>
Date: Mon, 28 Mar 2011 22:40:53 +0000
Subject: [PATCH] net: gre: provide multicast mappings for ipv4 and ipv6
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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>
---
include/net/if_inet6.h | 16 ++++++++++++++++
include/net/ip.h | 8 ++++++++
net/ipv4/arp.c | 3 +++
net/ipv6/ndisc.c | 2 ++
4 files changed, 29 insertions(+)
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 04977eefb0ee..fccc2180c61b 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -286,5 +286,21 @@ static inline void ipv6_ib_mc_map(const struct in6_addr *addr,
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
diff --git a/include/net/ip.h b/include/net/ip.h
index a4f631108c54..7c416583b710 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -339,6 +339,14 @@ static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, ch
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
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 090d273d7865..1b74d3b64371 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -215,6 +215,9 @@ int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
case ARPHRD_INFINIBAND:
ip_ib_mc_map(addr, dev->broadcast, haddr);
return 0;
+ case ARPHRD_IPGRE:
+ ip_ipgre_mc_map(addr, dev->broadcast, haddr);
+ return 0;
default:
if (dir) {
memcpy(haddr, dev->broadcast, dev->addr_len);
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 0e49c9db3c98..92f952d093db 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -341,6 +341,8 @@ int ndisc_mc_map(struct in6_addr *addr, char *buf, struct net_device *dev, int d
case ARPHRD_INFINIBAND:
ipv6_ib_mc_map(addr, dev->broadcast, buf);
return 0;
+ case ARPHRD_IPGRE:
+ return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
default:
if (dir) {
memcpy(buf, dev->broadcast, dev->addr_len);
--
2.34.1