Commit 93ca3bb5 authored by Timo Teräs's avatar Timo Teräs Committed by David S. Miller
Browse files

net: gre: provide multicast mappings for ipv4 and ipv6 



My commit 6d55cb91 (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: default avatarDoug Kehn <rdkehn@yahoo.com>
Signed-off-by: default avatarTimo Teräs <timo.teras@iki.fi>
Acked-by: default avatarDoug Kehn <rdkehn@yahoo.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1459a3cc

include/net/if_inet6.h

+16 −0
Original line number Diff line number Diff line
@@ -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

include/net/ip.h

+8 −0
Original line number Diff line number Diff line
@@ -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

net/ipv4/arp.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

net/ipv6/ndisc.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

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