From 46af31800b6916c92fffa529dc3c357008da957d Mon Sep 17 00:00:00 2001
From: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Date: Wed, 9 Mar 2011 20:09:58 +0000
Subject: ipv4: Fix PMTU update.
On current net-next-2.6, when Linux receives ICMP Type: 3, Code: 4
(Destination unreachable (Fragmentation needed)),
icmp_unreach
-> ip_rt_frag_needed
(peer->pmtu_expires is set here)
-> tcp_v4_err
-> do_pmtu_discovery
-> ip_rt_update_pmtu
(peer->pmtu_expires is already set,
so check_peer_pmtu is skipped.)
-> check_peer_pmtu
check_peer_pmtu is skipped and MTU is not updated.
To fix this, let check_peer_pmtu execute unconditionally.
And some minor fixes
1) Avoid potential peer->pmtu_expires set to be zero.
2) In check_peer_pmtu, argument of time_before is reversed.
3) check_peer_pmtu expects peer->pmtu_orig is initialized as zero,
but not initialized.
Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/inetpeer.c | 1 +
net/ipv4/route.c | 22 +++++++++++++++++-----
2 files changed, 18 insertions(+), 5 deletions(-)
(limited to 'net')
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 6442c35edb0..86b1d0878df 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -511,6 +511,7 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
p->rate_tokens = 0;
p->rate_last = 0;
p->pmtu_expires = 0;
+ p->pmtu_orig = 0;
memset(&p->redirect_learned, 0, sizeof(p->redirect_learned));
INIT_LIST_HEAD(&p->unused);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5655095a89e..209989cf7d1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1533,9 +1533,15 @@ unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
if (mtu < ip_rt_min_pmtu)
mtu = ip_rt_min_pmtu;
if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
+ unsigned long pmtu_expires;
+
+ pmtu_expires = jiffies + ip_rt_mtu_expires;
+ if (!pmtu_expires)
+ pmtu_expires = 1UL;
+
est_mtu = mtu;
peer->pmtu_learned = mtu;
- peer->pmtu_expires = jiffies + ip_rt_mtu_expires;
+ peer->pmtu_expires = pmtu_expires;
}
inet_putpeer(peer);
@@ -1549,7 +1555,7 @@ static void check_peer_pmtu(struct dst_entry *dst, struct inet_peer *peer)
{
unsigned long expires = peer->pmtu_expires;
- if (time_before(expires, jiffies)) {
+ if (time_before(jiffies, expires)) {
u32 orig_dst_mtu = dst_mtu(dst);
if (peer->pmtu_learned < orig_dst_mtu) {
if (!peer->pmtu_orig)
@@ -1574,14 +1580,20 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
if (mtu < ip_rt_min_pmtu)
mtu = ip_rt_min_pmtu;
if (!peer->pmtu_expires || mtu < peer->pmtu_learned) {
+ unsigned long pmtu_expires;
+
+ pmtu_expires = jiffies + ip_rt_mtu_expires;
+ if (!pmtu_expires)
+ pmtu_expires = 1UL;
+
peer->pmtu_learned = mtu;
- peer->pmtu_expires = jiffies + ip_rt_mtu_expires;
+ peer->pmtu_expires = pmtu_expires;
atomic_inc(&__rt_peer_genid);
rt->rt_peer_genid = rt_peer_genid();
-
- check_peer_pmtu(dst, peer);
}
+ check_peer_pmtu(dst, peer);
+
inet_putpeer(peer);
}
}
--
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