From 432e05d328921c68c35bfdeff7d7b7400b8e3d1a Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Wed, 1 Aug 2018 00:36:03 +0200 Subject: 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 Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller --- net/ipv4/ip_forward.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/ipv4/ip_forward.c') 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, -- cgit v1.2.3