act_mirred: clear skb->tstamp on redirect

Eric Dumazet · davem330 · commit 7236ead1b149 · 2018-11-11T10:21:31.000-08:00
If sch_fq is used at ingress, skbs that might have been timestamped by net_timestamp_set() if a packet capture is requesting timestamps could be delayed by arbitrary amount of time, since sch_fq time base is MONOTONIC. Fix this problem by moving code from sch_netem.c to act_mirred.c. Fixes: fb420d5 ("tcp/fq: move back to CLOCK_MONOTONIC") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
@@ -258,7 +258,8 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
 	if (is_redirect) {
 		skb2->tc_redirected = 1;
 		skb2->tc_from_ingress = skb2->tc_at_ingress;
-
+		if (skb2->tc_from_ingress)
+			skb2->tstamp = 0;
 		/* let's the caller reinsert the packet, if possible */
 		if (use_reinsert) {
 			res->ingress = want_ingress;
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
@@ -648,15 +648,6 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
 			 */
 			skb->dev = qdisc_dev(sch);
 
-#ifdef CONFIG_NET_CLS_ACT
-			/*
-			 * If it's at ingress let's pretend the delay is
-			 * from the network (tstamp will be updated).
-			 */
-			if (skb->tc_redirected && skb->tc_from_ingress)
-				skb->tstamp = 0;
-#endif
-
 			if (q->slot.slot_next) {
 				q->slot.packets_left--;
 				q->slot.bytes_left -= qdisc_pkt_len(skb);
