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Commit b42835db authored by David S. Miller's avatar David S. Miller
Browse files

ipv6: Make icmp route lookup code a bit clearer. 



The route lookup code in icmpv6_send() is slightly tricky as a result of
having to handle all of the requirements of RFC 4301 host relookups.

Pull the route resolution into a seperate function, so that the error
handling and route reference counting is hopefully easier to see and
contained wholly within this new routine.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f6d460cf

net/ipv6/icmp.c

+66 −51
Original line number Diff line number Diff line
@@ -300,6 +300,70 @@ static void mip6_addr_swap(struct sk_buff *skb) 
static inline void mip6_addr_swap(struct sk_buff *skb) {}

#endif



static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *skb,

					     struct sock *sk, struct flowi *fl)

{

	struct dst_entry *dst, *dst2;

	struct flowi fl2;

	int err;



	err = ip6_dst_lookup(sk, &dst, fl);

	if (err)

		return ERR_PTR(err);



	/*

	 * We won't send icmp if the destination is known

	 * anycast.

	 */

	if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {

		LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");

		dst_release(dst);

		return ERR_PTR(-EINVAL);

	}



	/* No need to clone since we're just using its address. */

	dst2 = dst;



	err = xfrm_lookup(net, &dst, fl, sk, 0);

	switch (err) {

	case 0:

		if (dst != dst2)

			return dst;

		break;

	case -EPERM:

		dst = NULL;

		break;

	default:

		return ERR_PTR(err);

	}



	err = xfrm_decode_session_reverse(skb, &fl2, AF_INET6);

	if (err)

		goto relookup_failed;



	err = ip6_dst_lookup(sk, &dst2, &fl2);

	if (err)

		goto relookup_failed;



	err = xfrm_lookup(net, &dst2, &fl2, sk, XFRM_LOOKUP_ICMP);

	switch (err) {

	case 0:

		dst_release(dst);

		dst = dst2;

		break;

	case -EPERM:

		dst_release(dst);

		return ERR_PTR(err);

	default:

		goto relookup_failed;

	}



relookup_failed:

	if (dst)

		return dst;

	return ERR_PTR(err);

}



/*

 *	Send an ICMP message in response to a packet in error

 */
@@ -312,10 +376,8 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 
	struct ipv6_pinfo *np;

	struct in6_addr *saddr = NULL;

	struct dst_entry *dst;

	struct dst_entry *dst2;

	struct icmp6hdr tmp_hdr;

	struct flowi fl;

	struct flowi fl2;

	struct icmpv6_msg msg;

	int iif = 0;

	int addr_type = 0;
@@ -408,57 +470,10 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info) 
	if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))

		fl.oif = np->mcast_oif;



	err = ip6_dst_lookup(sk, &dst, &fl);

	if (err)

		goto out;



	/*

	 * We won't send icmp if the destination is known

	 * anycast.

	 */

	if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {

		LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");

		goto out_dst_release;

	}



	/* No need to clone since we're just using its address. */

	dst2 = dst;



	err = xfrm_lookup(net, &dst, &fl, sk, 0);

	switch (err) {

	case 0:

		if (dst != dst2)

			goto route_done;

		break;

	case -EPERM:

		dst = NULL;

		break;

	default:

		goto out;

	}



	if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6))

		goto relookup_failed;



	if (ip6_dst_lookup(sk, &dst2, &fl2))

		goto relookup_failed;



	err = xfrm_lookup(net, &dst2, &fl2, sk, XFRM_LOOKUP_ICMP);

	switch (err) {

	case 0:

		dst_release(dst);

		dst = dst2;

		break;

	case -EPERM:

		goto out_dst_release;

	default:

relookup_failed:

		if (!dst)

	dst = icmpv6_route_lookup(net, skb, sk, &fl);

	if (IS_ERR(dst))

		goto out;

		break;

	}



route_done:

	if (ipv6_addr_is_multicast(&fl.fl6_dst))

		hlimit = np->mcast_hops;

	else