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authorPetr Machata <petrm@mellanox.com>2018-08-01 00:36:03 +0200
committerDavid S. Miller <davem@davemloft.net>2018-08-01 09:52:30 -0700
commit432e05d328921c68c35bfdeff7d7b7400b8e3d1a (patch)
tree4c6becb6e6fa05882ba97f5ed121ad7d29eb6b33 /net/ipv4
parent83ba4645152d1177c161750e1064e3a8e7cee19b (diff)
downloadlinux-432e05d328921c68c35bfdeff7d7b7400b8e3d1a.tar.bz2
net: ipv4: Control SKB reprioritization after forwarding
After IPv4 packets are forwarded, the priority of the corresponding SKB is updated according to the TOS field of IPv4 header. This overrides any prioritization done earlier by e.g. an skbedit action or ingress-qos-map defined at a vlan device. Such overriding may not always be desirable. Even if the packet ends up being routed, which implies this is an L3 network node, an administrator may wish to preserve whatever prioritization was done earlier on in the pipeline. Therefore introduce a sysctl that controls this behavior. Keep the default value at 1 to maintain backward-compatible behavior. Signed-off-by: Petr Machata <petrm@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/af_inet.c1
-rw-r--r--net/ipv4/ip_forward.c3
-rw-r--r--net/ipv4/sysctl_net_ipv4.c9
3 files changed, 12 insertions, 1 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index ee707b91d1a7..20fda8fb8ffd 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1801,6 +1801,7 @@ static __net_init int inet_init_net(struct net *net)
* We set them here, in case sysctl is not compiled.
*/
net->ipv4.sysctl_ip_default_ttl = IPDEFTTL;
+ net->ipv4.sysctl_ip_fwd_update_priority = 1;
net->ipv4.sysctl_ip_dynaddr = 0;
net->ipv4.sysctl_ip_early_demux = 1;
net->ipv4.sysctl_udp_early_demux = 1;
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
index b54b948b0596..32662e9e5d21 100644
--- a/net/ipv4/ip_forward.c
+++ b/net/ipv4/ip_forward.c
@@ -143,7 +143,8 @@ int ip_forward(struct sk_buff *skb)
!skb_sec_path(skb))
ip_rt_send_redirect(skb);
- skb->priority = rt_tos2priority(iph->tos);
+ if (net->ipv4.sysctl_ip_fwd_update_priority)
+ skb->priority = rt_tos2priority(iph->tos);
return NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD,
net, NULL, skb, skb->dev, rt->dst.dev,
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 5fa335fd3852..e21dda015513 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -664,6 +664,15 @@ static struct ctl_table ipv4_net_table[] = {
.proc_handler = proc_dointvec,
},
{
+ .procname = "ip_forward_update_priority",
+ .data = &init_net.ipv4.sysctl_ip_fwd_update_priority,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
.procname = "ip_nonlocal_bind",
.data = &init_net.ipv4.sysctl_ip_nonlocal_bind,
.maxlen = sizeof(int),