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packet: tx timestamping on tpacket ring

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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>
This commit is contained in:
Willem de Bruijn
2013-04-23 00:39:28 +00:00
committed by David S. Miller
parent 92dea7c066
commit 2e31396fa1
2 changed files with 39 additions and 6 deletions
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33
net/packet/af_packet.c
View File

@@ -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) {