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packet: move hw/sw timestamp extraction into a small helper

This patch introduces a small, internal helper function, that is used by
PF_PACKET. Based on the flags that are passed, it extracts the packet
timestamp in the receive path. This is merely a refactoring to remove
some duplicate code in tpacket_rcv(), to make it more readable, and to
enable others to use this function in PF_PACKET as well, e.g. for TX.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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1 parent 6e94d1e commit 4b457bdf1dbc961b62252034b05d47ec3e5b85d2 @borkmann borkmann committed with davem330 Apr 16, 2013
Showing with 23 additions and 34 deletions.
  1. +23 −34 net/packet/af_packet.c
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57 net/packet/af_packet.c
@@ -1657,6 +1657,26 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
return 0;
}
+static void tpacket_get_timestamp(struct sk_buff *skb, struct timespec *ts,
+ unsigned int flags)
+{
+ struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
+
+ if (shhwtstamps) {
+ if ((flags & SOF_TIMESTAMPING_SYS_HARDWARE) &&
+ ktime_to_timespec_cond(shhwtstamps->syststamp, ts))
+ return;
+ if ((flags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
+ ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts))
+ return;
+ }
+
+ if (ktime_to_timespec_cond(skb->tstamp, ts))
+ return;
+
+ getnstimeofday(ts);
+}
+
static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
@@ -1670,9 +1690,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
unsigned long status = TP_STATUS_USER;
unsigned short macoff, netoff, hdrlen;
struct sk_buff *copy_skb = NULL;
- struct timeval tv;
struct timespec ts;
- struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
@@ -1755,42 +1773,23 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
spin_unlock(&sk->sk_receive_queue.lock);
skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
+ tpacket_get_timestamp(skb, &ts, po->tp_tstamp);
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_len = skb->len;
h.h1->tp_snaplen = snaplen;
h.h1->tp_mac = macoff;
h.h1->tp_net = netoff;
- if ((po->tp_tstamp & SOF_TIMESTAMPING_SYS_HARDWARE)
- && shhwtstamps->syststamp.tv64)
- tv = ktime_to_timeval(shhwtstamps->syststamp);
- else if ((po->tp_tstamp & SOF_TIMESTAMPING_RAW_HARDWARE)
- && shhwtstamps->hwtstamp.tv64)
- tv = ktime_to_timeval(shhwtstamps->hwtstamp);
- else if (skb->tstamp.tv64)
- tv = ktime_to_timeval(skb->tstamp);
- else
- do_gettimeofday(&tv);
- h.h1->tp_sec = tv.tv_sec;
- h.h1->tp_usec = tv.tv_usec;
+ h.h1->tp_sec = ts.tv_sec;
+ h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
hdrlen = sizeof(*h.h1);
break;
case TPACKET_V2:
h.h2->tp_len = skb->len;
h.h2->tp_snaplen = snaplen;
h.h2->tp_mac = macoff;
h.h2->tp_net = netoff;
- if ((po->tp_tstamp & SOF_TIMESTAMPING_SYS_HARDWARE)
- && shhwtstamps->syststamp.tv64)
- ts = ktime_to_timespec(shhwtstamps->syststamp);
- else if ((po->tp_tstamp & SOF_TIMESTAMPING_RAW_HARDWARE)
- && shhwtstamps->hwtstamp.tv64)
- ts = ktime_to_timespec(shhwtstamps->hwtstamp);
- else if (skb->tstamp.tv64)
- ts = ktime_to_timespec(skb->tstamp);
- else
- getnstimeofday(&ts);
h.h2->tp_sec = ts.tv_sec;
h.h2->tp_nsec = ts.tv_nsec;
if (vlan_tx_tag_present(skb)) {
@@ -1811,16 +1810,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
h.h3->tp_snaplen = snaplen;
h.h3->tp_mac = macoff;
h.h3->tp_net = netoff;
- if ((po->tp_tstamp & SOF_TIMESTAMPING_SYS_HARDWARE)
- && shhwtstamps->syststamp.tv64)
- ts = ktime_to_timespec(shhwtstamps->syststamp);
- else if ((po->tp_tstamp & SOF_TIMESTAMPING_RAW_HARDWARE)
- && shhwtstamps->hwtstamp.tv64)
- ts = ktime_to_timespec(shhwtstamps->hwtstamp);
- else if (skb->tstamp.tv64)
- ts = ktime_to_timespec(skb->tstamp);
- else
- getnstimeofday(&ts);
h.h3->tp_sec = ts.tv_sec;
h.h3->tp_nsec = ts.tv_nsec;
hdrlen = sizeof(*h.h3);

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