net: support time stamping in phy devices.

This patch adds a new networking option to allow hardware time stamps
from PHY devices. When enabled, likely candidates among incoming and
outgoing network packets are offered to the PHY driver for possible
time stamping. When accepted by the PHY driver, incoming packets are
deferred for later delivery by the driver.

The patch also adds phylib driver methods for the SIOCSHWTSTAMP ioctl
and callbacks for transmit and receive time stamping. Drivers may
optionally implement these functions.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 144 insertions, 1 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 0d68b40..b325094 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -86,6 +86,16 @@ config NETWORK_SECMARK
 	  to nfmark, but designated for security purposes.
 	  If you are unsure how to answer this question, answer N.
 
+config NETWORK_PHY_TIMESTAMPING
+	bool "Timestamping in PHY devices"
+	depends on EXPERIMENTAL
+	help
+	  This allows timestamping of network packets by PHYs with
+	  hardware timestamping capabilities. This option adds some
+	  overhead in the transmit and receive paths.
+
+	  If you are unsure how to answer this question, answer N.
+
 menuconfig NETFILTER
 	bool "Network packet filtering framework (Netfilter)"
 	---help---
diff --git a/net/core/Makefile b/net/core/Makefile
index 51c3eec..8a04dd2 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -18,4 +18,4 @@ obj-$(CONFIG_NET_DMA) += user_dma.o
 obj-$(CONFIG_FIB_RULES) += fib_rules.o
 obj-$(CONFIG_TRACEPOINTS) += net-traces.o
 obj-$(CONFIG_NET_DROP_MONITOR) += drop_monitor.o
-
+obj-$(CONFIG_NETWORK_PHY_TIMESTAMPING) += timestamping.o
diff --git a/net/core/dev.c b/net/core/dev.c
index e2b9fa2..1c002c7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2957,6 +2957,9 @@ int netif_receive_skb(struct sk_buff *skb)
 	if (netdev_tstamp_prequeue)
 		net_timestamp_check(skb);
 
+	if (skb_defer_rx_timestamp(skb))
+		return NET_RX_SUCCESS;
+
 #ifdef CONFIG_RPS
 	{
 		struct rps_dev_flow voidflow, *rflow = &voidflow;
diff --git a/net/core/timestamping.c b/net/core/timestamping.c
new file mode 100644
index 0000000..0ae6c22
--- /dev/null
+++ b/net/core/timestamping.c
@@ -0,0 +1,126 @@
+/*
+ * PTP 1588 clock support - support for timestamping in PHY devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/errqueue.h>
+#include <linux/phy.h>
+#include <linux/ptp_classify.h>
+#include <linux/skbuff.h>
+
+static struct sock_filter ptp_filter[] = {
+	PTP_FILTER
+};
+
+static unsigned int classify(struct sk_buff *skb)
+{
+	if (likely(skb->dev &&
+		   skb->dev->phydev &&
+		   skb->dev->phydev->drv))
+		return sk_run_filter(skb, ptp_filter, ARRAY_SIZE(ptp_filter));
+	else
+		return PTP_CLASS_NONE;
+}
+
+void skb_clone_tx_timestamp(struct sk_buff *skb)
+{
+	struct phy_device *phydev;
+	struct sk_buff *clone;
+	struct sock *sk = skb->sk;
+	unsigned int type;
+
+	if (!sk)
+		return;
+
+	type = classify(skb);
+
+	switch (type) {
+	case PTP_CLASS_V1_IPV4:
+	case PTP_CLASS_V1_IPV6:
+	case PTP_CLASS_V2_IPV4:
+	case PTP_CLASS_V2_IPV6:
+	case PTP_CLASS_V2_L2:
+	case PTP_CLASS_V2_VLAN:
+		phydev = skb->dev->phydev;
+		if (likely(phydev->drv->txtstamp)) {
+			clone = skb_clone(skb, GFP_ATOMIC);
+			if (!clone)
+				return;
+			clone->sk = sk;
+			phydev->drv->txtstamp(phydev, clone, type);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+void skb_complete_tx_timestamp(struct sk_buff *skb,
+			       struct skb_shared_hwtstamps *hwtstamps)
+{
+	struct sock *sk = skb->sk;
+	struct sock_exterr_skb *serr;
+	int err;
+
+	if (!hwtstamps)
+		return;
+
+	*skb_hwtstamps(skb) = *hwtstamps;
+	serr = SKB_EXT_ERR(skb);
+	memset(serr, 0, sizeof(*serr));
+	serr->ee.ee_errno = ENOMSG;
+	serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
+	skb->sk = NULL;
+	err = sock_queue_err_skb(sk, skb);
+	if (err)
+		kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
+
+bool skb_defer_rx_timestamp(struct sk_buff *skb)
+{
+	struct phy_device *phydev;
+	unsigned int type;
+
+	skb_push(skb, ETH_HLEN);
+
+	type = classify(skb);
+
+	skb_pull(skb, ETH_HLEN);
+
+	switch (type) {
+	case PTP_CLASS_V1_IPV4:
+	case PTP_CLASS_V1_IPV6:
+	case PTP_CLASS_V2_IPV4:
+	case PTP_CLASS_V2_IPV6:
+	case PTP_CLASS_V2_L2:
+	case PTP_CLASS_V2_VLAN:
+		phydev = skb->dev->phydev;
+		if (likely(phydev->drv->rxtstamp))
+			return phydev->drv->rxtstamp(phydev, skb, type);
+		break;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+void __init skb_timestamping_init(void)
+{
+	BUG_ON(sk_chk_filter(ptp_filter, ARRAY_SIZE(ptp_filter)));
+}
diff --git a/net/socket.c b/net/socket.c
index 6fe4841..2270b94 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2394,6 +2394,10 @@ static int __init sock_init(void)
 	netfilter_init();
 #endif
 
+#ifdef CONFIG_NETWORK_PHY_TIMESTAMPING
+	skb_timestamping_init();
+#endif
+
 	return 0;
 }