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Message-Id: <20120719.143526.163351764035435416.davem@davemloft.net>
Date: Thu, 19 Jul 2012 14:35:26 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH 09/16] 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>
---
include/net/dst.h | 1 +
net/ipv4/route.c | 41 +++++++++++++++++++++++++++++------------
2 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index 0df661a..baf5978 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -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
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 23078d6..f902d08 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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;
}
--
1.7.10.4
--
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