diff options
| author | Martin KaFai Lau <kafai@fb.com> | 2022-03-02 22:55:38 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-03-03 17:38:48 +0300 |
| commit | 27942a15209f564ed8ee2a9e126cb7b105181355 (patch) | |
| tree | e6ef34b008fa969dd0fbc371c5dec3999cc409e1 /net/core/dev.c | |
| parent | de799101519aad23c6096041ba2744d7b5517e6a (diff) | |
| download | linux-27942a15209f564ed8ee2a9e126cb7b105181355.tar.xz | |
net: Handle delivery_time in skb->tstamp during network tapping with af_packet
A latter patch will set the skb->mono_delivery_time to flag the skb->tstamp
is used as the mono delivery_time (EDT) instead of the (rcv) timestamp.
skb_clear_tstamp() will then keep this delivery_time during forwarding.
This patch is to make the network tapping (with af_packet) to handle
the delivery_time stored in skb->tstamp.
Regardless of tapping at the ingress or egress, the tapped skb is
received by the af_packet socket, so it is ingress to the af_packet
socket and it expects the (rcv) timestamp.
When tapping at egress, dev_queue_xmit_nit() is used. It has already
expected skb->tstamp may have delivery_time, so it does
skb_clone()+net_timestamp_set() to ensure the cloned skb has
the (rcv) timestamp before passing to the af_packet sk.
This patch only adds to clear the skb->mono_delivery_time
bit in net_timestamp_set().
When tapping at ingress, it currently expects the skb->tstamp is either 0
or the (rcv) timestamp. Meaning, the tapping at ingress path
has already expected the skb->tstamp could be 0 and it will get
the (rcv) timestamp by ktime_get_real() when needed.
There are two cases for tapping at ingress:
One case is af_packet queues the skb to its sk_receive_queue.
The skb is either not shared or new clone created. The newly
added skb_clear_delivery_time() is called to clear the
delivery_time (if any) and set the (rcv) timestamp if
needed before the skb is queued to the sk_receive_queue.
Another case, the ingress skb is directly copied to the rx_ring
and tpacket_get_timestamp() is used to get the (rcv) timestamp.
The newly added skb_tstamp() is used in tpacket_get_timestamp()
to check the skb->mono_delivery_time bit before returning skb->tstamp.
As mentioned earlier, the tapping@ingress has already expected
the skb may not have the (rcv) timestamp (because no sk has asked
for it) and has handled this case by directly calling ktime_get_real().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index c9e54e5ad48d..e128f26711eb 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2047,7 +2047,8 @@ void net_dec_egress_queue(void) EXPORT_SYMBOL_GPL(net_dec_egress_queue); #endif -static DEFINE_STATIC_KEY_FALSE(netstamp_needed_key); +DEFINE_STATIC_KEY_FALSE(netstamp_needed_key); +EXPORT_SYMBOL(netstamp_needed_key); #ifdef CONFIG_JUMP_LABEL static atomic_t netstamp_needed_deferred; static atomic_t netstamp_wanted; @@ -2108,6 +2109,7 @@ EXPORT_SYMBOL(net_disable_timestamp); static inline void net_timestamp_set(struct sk_buff *skb) { skb->tstamp = 0; + skb->mono_delivery_time = 0; if (static_branch_unlikely(&netstamp_needed_key)) __net_timestamp(skb); } |