Commit 2d3b479d authored by david decotigny's avatar david decotigny Committed by David S. Miller
Browse files

net-sysfs: expose number of carrier on/off changes 



This allows to monitor carrier on/off transitions and detect link
flapping issues:
 - new /sys/class/net/X/carrier_changes
 - new rtnetlink IFLA_CARRIER_CHANGES (getlink)

Tested:
  - grep . /sys/class/net/*/carrier_changes
    + ip link set dev X down/up
    + plug/unplug cable
  - updated iproute2: prints IFLA_CARRIER_CHANGES
  - iproute2 20121211-2 (debian): unchanged behavior

Signed-off-by: default avatarDavid Decotigny <decot@googlers.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9c76a114

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -1308,6 +1308,9 @@ struct net_device { 
	atomic_long_t		rx_dropped;

	atomic_long_t		tx_dropped;



	/* Stats to monitor carrier on<->off transitions */

	atomic_t		carrier_changes;



#ifdef CONFIG_WIRELESS_EXT

	/* List of functions to handle Wireless Extensions (instead of ioctl).

	 * See <net/iw_handler.h> for details. Jean II */

include/uapi/linux/if_link.h

+1 −0
Original line number Diff line number Diff line
@@ -144,6 +144,7 @@ enum { 
	IFLA_NUM_RX_QUEUES,

	IFLA_CARRIER,

	IFLA_PHYS_PORT_ID,

	IFLA_CARRIER_CHANGES,

	__IFLA_MAX

};

net/core/net-sysfs.c

+11 −0
Original line number Diff line number Diff line
@@ -253,6 +253,16 @@ static ssize_t operstate_show(struct device *dev, 
}

static DEVICE_ATTR_RO(operstate);



static ssize_t carrier_changes_show(struct device *dev,

				    struct device_attribute *attr,

				    char *buf)

{

	struct net_device *netdev = to_net_dev(dev);

	return sprintf(buf, fmt_dec,

		       atomic_read(&netdev->carrier_changes));

}

static DEVICE_ATTR_RO(carrier_changes);



/* read-write attributes */



static int change_mtu(struct net_device *net, unsigned long new_mtu)
@@ -386,6 +396,7 @@ static struct attribute *net_class_attrs[] = { 
	&dev_attr_duplex.attr,

	&dev_attr_dormant.attr,

	&dev_attr_operstate.attr,

	&dev_attr_carrier_changes.attr,

	&dev_attr_ifalias.attr,

	&dev_attr_carrier.attr,

	&dev_attr_mtu.attr,

net/core/rtnetlink.c

+5 −1
Original line number Diff line number Diff line
@@ -822,6 +822,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, 
	       + nla_total_size(4) /* IFLA_NUM_RX_QUEUES */

	       + nla_total_size(1) /* IFLA_OPERSTATE */

	       + nla_total_size(1) /* IFLA_LINKMODE */

	       + nla_total_size(4) /* IFLA_CARRIER_CHANGES */

	       + nla_total_size(ext_filter_mask

			        & RTEXT_FILTER_VF ? 4 : 0) /* IFLA_NUM_VF */

	       + rtnl_vfinfo_size(dev, ext_filter_mask) /* IFLA_VFINFO_LIST */
@@ -970,7 +971,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
	    (dev->qdisc &&

	     nla_put_string(skb, IFLA_QDISC, dev->qdisc->ops->id)) ||

	    (dev->ifalias &&

	     nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)))

	     nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)) ||

	    nla_put_u32(skb, IFLA_CARRIER_CHANGES,

			atomic_read(&dev->carrier_changes)))

		goto nla_put_failure;



	if (1) {
@@ -1147,6 +1150,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = { 
	[IFLA_NUM_TX_QUEUES]	= { .type = NLA_U32 },

	[IFLA_NUM_RX_QUEUES]	= { .type = NLA_U32 },

	[IFLA_PHYS_PORT_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_PORT_ID_LEN },

	[IFLA_CARRIER_CHANGES]	= { .type = NLA_U32 },  /* ignored */

};



static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {

net/sched/sch_generic.c

+2 −0
Original line number Diff line number Diff line
@@ -310,6 +310,7 @@ void netif_carrier_on(struct net_device *dev) 
	if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {

		if (dev->reg_state == NETREG_UNINITIALIZED)

			return;

		atomic_inc(&dev->carrier_changes);

		linkwatch_fire_event(dev);

		if (netif_running(dev))

			__netdev_watchdog_up(dev);
@@ -328,6 +329,7 @@ void netif_carrier_off(struct net_device *dev) 
	if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {

		if (dev->reg_state == NETREG_UNINITIALIZED)

			return;

		atomic_inc(&dev->carrier_changes);

		linkwatch_fire_event(dev);

	}

}

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