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authorSabrina Dubroca <sd@queasysnail.net>2018-11-16 16:58:19 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-11-23 08:20:34 +0100
commit5367cdf3e1587f1c58af0d5be98a1e9fb46eea68 (patch)
tree2595f51886d79144bbb8556f00e4c40b5e0f9285 /net/ipv4
parenta09bd930e90a5c13a9f7367da76af1fe0ee1f8ca (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/ipv4')
-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 0fd1976ab63b..2220a1b396af 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -80,7 +80,7 @@ void 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;