Patchwork [net-next,2/2] packet: move hw/sw timestamp extraction into a small helper

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Submitter Daniel Borkmann
Date April 16, 2013, 11:29 a.m.
Message ID <1366111751-14886-2-git-send-email-dborkman@redhat.com>
Download mbox | patch
Permalink /patch/236944/
State Accepted
Delegated to: David Miller
Headers show

Comments

Daniel Borkmann - April 16, 2013, 11:29 a.m.
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>
---
 v1->v2:
   - To not break user space, I decided for now to not get rid of tp_tstamp
   - After some more thinking about it, I'm now with Willem to not make it
     too generic, thus having it stay in af_packet.c
   - Use ktime_to_timespec_cond() from patch 1 to make it more similar to
     __sock_recv_timestamp()

 net/packet/af_packet.c | 57 ++++++++++++++++++++------------------------------
 1 file changed, 23 insertions(+), 34 deletions(-)
Willem de Bruijn - April 16, 2013, 2:26 p.m.
On Tue, Apr 16, 2013 at 7:29 AM, Daniel Borkmann <dborkman@redhat.com> wrote:
> 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.

This looks great to me. Merge is dependent on the
ktime_to_timespec_cond patch, but once it makes it in, I will resubmit
txring timestamp to use this function.

> Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
> ---
>  v1->v2:
>    - To not break user space, I decided for now to not get rid of tp_tstamp
>    - After some more thinking about it, I'm now with Willem to not make it
>      too generic, thus having it stay in af_packet.c
>    - Use ktime_to_timespec_cond() from patch 1 to make it more similar to
>      __sock_recv_timestamp()
>
>  net/packet/af_packet.c | 57 ++++++++++++++++++++------------------------------
>  1 file changed, 23 insertions(+), 34 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 77d71f8..e381adf 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1663,6 +1663,26 @@ drop:
>         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)
>  {
> @@ -1681,9 +1701,7 @@ 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;
> @@ -1766,6 +1784,7 @@ 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:
> @@ -1773,18 +1792,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
>                 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:
> @@ -1792,16 +1801,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
>                 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)) {
> @@ -1822,16 +1821,6 @@ 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);
> --
> 1.7.11.7
>
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David Miller - April 19, 2013, 8:50 p.m.
From: Daniel Borkmann <dborkman@redhat.com>
Date: Tue, 16 Apr 2013 13:29:11 +0200

> 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>

Applied.
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Patch

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 77d71f8..e381adf 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1663,6 +1663,26 @@  drop:
 	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)
 {
@@ -1681,9 +1701,7 @@  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;
@@ -1766,6 +1784,7 @@  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:
@@ -1773,18 +1792,8 @@  static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		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:
@@ -1792,16 +1801,6 @@  static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		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)) {
@@ -1822,16 +1821,6 @@  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);