git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 770f58d7866dfb0bc61a797ae601b7e481d741d5 Mon Sep 17 00:00:00 2001
   2 From: Steffen Klassert <steffen.klassert@secunet.com>
   3 Date: Sun, 7 Oct 2012 22:48:18 +0000
   4 Subject: ipv4: Don't create nh exeption when the device mtu is smaller than the reported pmtu
   5
   6
   7 From: Steffen Klassert <steffen.klassert@secunet.com>
   8
   9 [ Upstream commit 7f92d334ba19a0d8e96f8f8f092219553367d921 ]
  10
  11 When a local tool like tracepath tries to send packets bigger than
  12 the device mtu, we create a nh exeption and set the pmtu to device
  13 mtu. The device mtu does not expire, so check if the device mtu is
  14 smaller than the reported pmtu and don't crerate a nh exeption in
  15 that case.
  16
  17 Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
  18 Signed-off-by: David S. Miller <davem@davemloft.net>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20 ---
  21  net/ipv4/route.c |    3 +++
  22  1 file changed, 3 insertions(+)
  23
  24 --- a/net/ipv4/route.c
  25 +++ b/net/ipv4/route.c
  26 @@ -909,6 +909,9 @@ static void __ip_rt_update_pmtu(struct r
  27         struct dst_entry *dst = &rt->dst;
  28         struct fib_result res;
  29
  30 +       if (dst->dev->mtu < mtu)
  31 +               return;
  32 +
  33         if (mtu < ip_rt_min_pmtu)
  34                 mtu = ip_rt_min_pmtu;
  35