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| author | Willem de Bruijn <willemb@google.com> | 2013-04-23 00:39:28 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-04-25 01:22:22 -0400 |
| commit | 2e31396fa14be50a98c5d2b00416ebd74d381c1f (patch) | |
| tree | e01cf0a24659116265e189a68331bd74ebb48d42 /net/packet | |
| parent | 92dea7c06656f709a3957aacef20574ce3dbe6fc (diff) | |
| download | lwn-2e31396fa14be50a98c5d2b00416ebd74d381c1f.tar.gz lwn-2e31396fa14be50a98c5d2b00416ebd74d381c1f.zip | |
packet: tx timestamping on tpacket ring
When transmit timestamping is enabled at the socket level, record a
timestamp on packets written to a PACKET_TX_RING. Tx timestamps are
always looped to the application over the socket error queue. Software
timestamps are also written back into the packet frame header in the
packet ring.
Reported-by: Paul Chavent <paul.chavent@onera.fr>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 7e387ff64465..ec8ea27733ac 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -339,6 +339,37 @@ static int __packet_get_status(struct packet_sock *po, void *frame) } } +static void __packet_set_timestamp(struct packet_sock *po, void *frame, + ktime_t tstamp) +{ + union tpacket_uhdr h; + struct timespec ts; + + if (!ktime_to_timespec_cond(tstamp, &ts) || + !sock_flag(&po->sk, SOCK_TIMESTAMPING_SOFTWARE)) + return; + + h.raw = frame; + switch (po->tp_version) { + case TPACKET_V1: + h.h1->tp_sec = ts.tv_sec; + h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC; + break; + case TPACKET_V2: + h.h2->tp_sec = ts.tv_sec; + h.h2->tp_nsec = ts.tv_nsec; + break; + case TPACKET_V3: + default: + WARN(1, "TPACKET version not supported.\n"); + BUG(); + } + + /* one flush is safe, as both fields always lie on the same cacheline */ + flush_dcache_page(pgv_to_page(&h.h1->tp_sec)); + smp_wmb(); +} + static void *packet_lookup_frame(struct packet_sock *po, struct packet_ring_buffer *rb, unsigned int position, @@ -1877,6 +1908,7 @@ static void tpacket_destruct_skb(struct sk_buff *skb) ph = skb_shinfo(skb)->destructor_arg; BUG_ON(atomic_read(&po->tx_ring.pending) == 0); atomic_dec(&po->tx_ring.pending); + __packet_set_timestamp(po, ph, skb->tstamp); __packet_set_status(po, ph, TP_STATUS_AVAILABLE); } @@ -1900,6 +1932,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, skb->dev = dev; skb->priority = po->sk.sk_priority; skb->mark = po->sk.sk_mark; + sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags); skb_shinfo(skb)->destructor_arg = ph.raw; switch (po->tp_version) { |