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Message-Id: <20120718.112356.1409220904008377845.davem@davemloft.net>
Date: Wed, 18 Jul 2012 11:23:56 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH 08/15] 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: David S. Miller <davem@...emloft.net>
---
net/ipv4/route.c | 39 +++++++++++++++++++++++++++------------
1 file changed, 27 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 7ebf788..4d170a1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -657,7 +657,8 @@ out:
return fnhe;
}
-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;
@@ -716,8 +717,8 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
fnhe->fnhe_gw = new_gw;
spin_unlock_bh(&fnhe_lock);
}
- rt->rt_gateway = new_gw;
- rt->rt_flags |= RTCF_REDIRECTED;
+ if (kill_route)
+ rt->dst.obsolete = -2;
call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
}
neigh_release(n);
@@ -748,7 +749,7 @@ 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)
@@ -907,7 +908,7 @@ 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;
@@ -926,8 +927,7 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
}
spin_unlock_bh(&fnhe_lock);
}
- 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,
@@ -937,7 +937,14 @@ 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->expires = -2;
+ } 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,
@@ -983,7 +990,7 @@ 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);
}
}
@@ -998,7 +1005,7 @@ 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);
}
}
@@ -1008,7 +1015,13 @@ 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 obsoluete set to -1, that
+ * forces validation calls down into this function always.
+ *
+ * When a PMTU/redirect information update invalidates a
+ * route, this is indicated by setting obsolete to -2.
+ */
+ if (dst->obsolete == -2 || rt_is_expired(rt))
return NULL;
return dst;
}
@@ -1168,8 +1181,10 @@ static void rt_bind_exception(struct rtable *rt, struct fib_nh *nh, __be32 daddr
dst_set_expires(&rt->dst, diff);
}
}
- if (fnhe->fnhe_gw)
+ if (fnhe->fnhe_gw) {
+ rt->rt_flags |= RTCF_REDIRECTED;
rt->rt_gateway = fnhe->fnhe_gw;
+ }
fnhe->fnhe_stamp = jiffies;
break;
}
--
1.7.10.4
--
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