[PATCH nf] netfilter: nf_flow_table: clear skb tstamp before xmit

[PATCH nf] netfilter: nf_flow_table: clear skb tstamp before xmit

[Florian Westphal]

If 'fq' qdisc is used and a program has requested timestamps,
skb->tstamp needs to be cleared, else fq will treat these as
'transmit time'.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_flow_table_ip.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index d68c801dd614..b9e7dd6e60ce 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -228,7 +228,6 @@ static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
 {
 	skb_orphan(skb);
 	skb_dst_set_noref(skb, dst);
-	skb->tstamp = 0;
 	dst_output(state->net, state->sk, skb);
 	return NF_STOLEN;
 }
@@ -284,6 +283,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
 	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
 	iph = ip_hdr(skb);
 	ip_decrease_ttl(iph);
+	skb->tstamp = 0;
 
 	if (unlikely(dst_xfrm(&rt->dst))) {
 		memset(skb->cb, 0, sizeof(struct inet_skb_parm));
@@ -512,6 +512,7 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
 	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
 	ip6h = ipv6_hdr(skb);
 	ip6h->hop_limit--;
+	skb->tstamp = 0;
 
 	if (unlikely(dst_xfrm(&rt->dst))) {
 		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
-- 
2.21.0

Re: [PATCH nf] netfilter: nf_flow_table: clear skb tstamp before xmit

[Pablo Neira Ayuso]

On Tue, Aug 27, 2019 at 09:23:45PM +0200, Florian Westphal wrote:
> If 'fq' qdisc is used and a program has requested timestamps,
> skb->tstamp needs to be cleared, else fq will treat these as
> 'transmit time'.

Applied, thanks.