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: David Decotigny <de...@googlers.com>
---
include/linux/netdevice.h | 3 +++
include/uapi/linux/if_link.h | 1 +
net/core/net-sysfs.c | 11 +++++++++++
net/core/rtnetlink.c | 6 +++++-
net/sched/sch_generic.c | 2 ++
5 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 159c7e7..feb60c0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1316,6 +1316,9 @@ 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 */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 16410b6..9a7f7ac 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -144,6 +144,7 @@ enum {
IFLA_NUM_RX_QUEUES,
IFLA_CARRIER,
IFLA_PHYS_PORT_ID,
+ IFLA_CARRIER_CHANGES,
__IFLA_MAX
};
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index daed9a6..4623962 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -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,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e7c6006..d4ff417 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -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] = {
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index e82e43b..e1543b0 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -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);
}
}
--
1.9.1.423.g4596e3a
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