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>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 7e387ff..ec8ea27 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -339,6 +339,37 @@
}
}
+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 @@
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 @@
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) {