[PATCH v3] Enable tx timestamping on loopback and dummy

[Ezequiel Lara Gomez]

>From f3483202625648be728df39622360508f2fb03e1 Mon Sep 17 00:00:00 2001
From: Ezequiel Lara Gomez <ezego...@amazon.com>
Date: Sat, 11 Mar 2017 20:06:54 +0000
Subject: [PATCH v3] Enable tx timestamping on loopback and dummy

This enables testing of SO_TIMESTAMPING options by targetting localhost
addresses.

Tested on qemu using txtimestamping.c from the kernel selftests, and
ethtool -T.
---
Changes:
 * Added ethtool flags to both drivers to report they support timestamping.

 drivers/net/dummy.c    | 15 +++++++++++++++
 drivers/net/loopback.c | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 2c80611..149244a 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -35,6 +35,7 @@
 #include <linux/init.h>
 #include <linux/moduleparam.h>
 #include <linux/rtnetlink.h>
+#include <linux/net_tstamp.h>
 #include <net/rtnetlink.h>
 #include <linux/u64_stats_sync.h>
 
@@ -125,6 +126,7 @@ static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct 
net_device *dev)
        dstats->tx_bytes += skb->len;
        u64_stats_update_end(&dstats->syncp);
 
+       skb_tx_timestamp(skb);
        dev_kfree_skb(skb);
        return NETDEV_TX_OK;
 }
@@ -304,8 +306,21 @@ static void dummy_get_drvinfo(struct net_device *dev,
        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
 }
 
+static int dummy_get_ts_info(struct net_device *dev,
+                             struct ethtool_ts_info *ts_info)
+{
+       ts_info->so_timestamping = SOF_TIMESTAMPING_TX_SOFTWARE |
+                                  SOF_TIMESTAMPING_RX_SOFTWARE |
+                                  SOF_TIMESTAMPING_SOFTWARE;
+
+       ts_info->phc_index = -1;
+
+       return 0;
+};
+
 static const struct ethtool_ops dummy_ethtool_ops = {
        .get_drvinfo            = dummy_get_drvinfo,
+       .get_ts_info            = dummy_get_ts_info,
 };
 
 static void dummy_free_netdev(struct net_device *dev)
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 122cc2d..3a60d27 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -55,6 +55,7 @@
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/percpu.h>
+#include <linux/net_tstamp.h>
 #include <net/net_namespace.h>
 #include <linux/u64_stats_sync.h>
 
@@ -74,6 +75,7 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb,
        struct pcpu_lstats *lb_stats;
        int len;
 
+       skb_tx_timestamp(skb);
        skb_orphan(skb);
 
        /* Before queueing this packet to netif_rx(),
@@ -129,8 +131,21 @@ static u32 always_on(struct net_device *dev)
        return 1;
 }
 
+static int loopback_get_ts_info(struct net_device *netdev,
+                               struct ethtool_ts_info *ts_info)
+{
+       ts_info->so_timestamping = SOF_TIMESTAMPING_TX_SOFTWARE |
+                                  SOF_TIMESTAMPING_RX_SOFTWARE |
+                                  SOF_TIMESTAMPING_SOFTWARE;
+
+       ts_info->phc_index = -1;
+
+       return 0;
+};
+
 static const struct ethtool_ops loopback_ethtool_ops = {
        .get_link               = always_on,
+       .get_ts_info            = loopback_get_ts_info,
 };
 
 static int loopback_dev_init(struct net_device *dev)
-- 
1.9.1

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