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authorSabrina Dubroca <sd@queasysnail.net>2018-11-16 16:58:19 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-11-27 16:07:57 +0100
commit7876c2d6ced154eb7eff3587d75f02eda3a8f45f (patch)
tree3c437f7ccd61aaf5a90fc87496b8f747c0cbf859 /net
parent8c1741548937903b02e92b6fe2d14d90acedf14d (diff)
ip_tunnel: don't force DF when MTU is locked
[ Upstream commit 16f7eb2b77b55da816c4e207f3f9440a8cafc00a ] The various types of tunnels running over IPv4 can ask to set the DF bit to do PMTU discovery. However, PMTU discovery is subject to the threshold set by the net.ipv4.route.min_pmtu sysctl, and is also disabled on routes with "mtu lock". In those cases, we shouldn't set the DF bit. This patch makes setting the DF bit conditional on the route's MTU locking state. This issue seems to be older than git history. Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_tunnel_core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index dbda0565781c..4916d1857b75 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -71,7 +71,7 @@ int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
iph->version = 4;
iph->ihl = sizeof(struct iphdr) >> 2;
- iph->frag_off = df;
+ iph->frag_off = ip_mtu_locked(&rt->dst) ? 0 : df;
iph->protocol = proto;
iph->tos = tos;
iph->daddr = dst;