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Commit ceb33206 authored by David S. Miller's avatar David S. Miller
Browse files

ipv4: Kill routes during PMTU/redirect updates. 



Mark them obsolete so there will be a re-lookup to fetch the
FIB nexthop exception info.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f5b0a874

include/net/dst.h

+1 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ struct dst_entry { 
#define DST_OBSOLETE_NONE	0

#define DST_OBSOLETE_DEAD	2

#define DST_OBSOLETE_FORCE_CHK	-1

#define DST_OBSOLETE_KILL	-2

	unsigned short		header_len;	/* more space at head required */

	unsigned short		trailer_len;	/* space to reserve at tail */

#ifdef CONFIG_IP_ROUTE_CLASSID

net/ipv4/route.c

+29 −12
Original line number Diff line number Diff line
@@ -673,7 +673,8 @@ out_unlock: 
	return;

}



static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4)

static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,

			     bool kill_route)

{

	__be32 new_gw = icmp_hdr(skb)->un.gateway;

	__be32 old_gw = ip_hdr(skb)->saddr;
@@ -728,8 +729,8 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow 
				update_or_create_fnhe(nh, fl4->daddr, new_gw,

						      0, 0);

			}

			rt->rt_gateway = new_gw;

			rt->rt_flags |= RTCF_REDIRECTED;

			if (kill_route)

				rt->dst.obsolete = DST_OBSOLETE_KILL;

			call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);

		}

		neigh_release(n);
@@ -760,7 +761,7 @@ static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buf 
	rt = (struct rtable *) dst;



	ip_rt_build_flow_key(&fl4, sk, skb);

	__ip_do_redirect(rt, skb, &fl4);

	__ip_do_redirect(rt, skb, &fl4, true);

}



static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
@@ -919,7 +920,7 @@ out: kfree_skb(skb); 
	return 0;

}



static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)

static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)

{

	struct fib_result res;
@@ -932,8 +933,7 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 
		update_or_create_fnhe(nh, fl4->daddr, 0, mtu,

				      jiffies + ip_rt_mtu_expires);

	}

	rt->rt_pmtu = mtu;

	dst_set_expires(&rt->dst, ip_rt_mtu_expires);

	return mtu;

}



static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
@@ -943,7 +943,14 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 
	struct flowi4 fl4;



	ip_rt_build_flow_key(&fl4, sk, skb);

	__ip_rt_update_pmtu(rt, &fl4, mtu);

	mtu = __ip_rt_update_pmtu(rt, &fl4, mtu);



	if (!rt->rt_pmtu) {

		dst->obsolete = DST_OBSOLETE_KILL;

	} else {

		rt->rt_pmtu = mtu;

		dst_set_expires(&rt->dst, ip_rt_mtu_expires);

	}

}



void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
@@ -989,7 +996,7 @@ void ipv4_redirect(struct sk_buff *skb, struct net *net, 
			 RT_TOS(iph->tos), protocol, mark, flow_flags);

	rt = __ip_route_output_key(net, &fl4);

	if (!IS_ERR(rt)) {

		__ip_do_redirect(rt, skb, &fl4);

		__ip_do_redirect(rt, skb, &fl4, false);

		ip_rt_put(rt);

	}

}
@@ -1004,7 +1011,7 @@ void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 
	__build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);

	rt = __ip_route_output_key(sock_net(sk), &fl4);

	if (!IS_ERR(rt)) {

		__ip_do_redirect(rt, skb, &fl4);

		__ip_do_redirect(rt, skb, &fl4, false);

		ip_rt_put(rt);

	}

}
@@ -1014,7 +1021,15 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 
{

	struct rtable *rt = (struct rtable *) dst;



	if (rt_is_expired(rt))

	/* All IPV4 dsts are created with ->obsolete set to the value

	 * DST_OBSOLETE_FORCE_CHK which forces validation calls down

	 * into this function always.

	 *

	 * When a PMTU/redirect information update invalidates a

	 * route, this is indicated by setting obsolete to

	 * DST_OBSOLETE_KILL.

	 */

	if (dst->obsolete == DST_OBSOLETE_KILL || rt_is_expired(rt))

		return NULL;

	return dst;

}
@@ -1186,8 +1201,10 @@ restart: 
				dst_set_expires(&rt->dst, diff);

			}

		}

		if (gw)

		if (gw) {

			rt->rt_flags |= RTCF_REDIRECTED;

			rt->rt_gateway = gw;

		}

		fnhe->fnhe_stamp = jiffies;

		break;

	}