net: core: Expose number of link up/down transitions

Expose the number of times the link has been going UP or DOWN, and
update the "carrier_changes" counter to be the sum of these two events.
While at it, also update the sysfs-class-net documentation to cover:
carrier_changes (3.15), carrier_up_count (4.16) and carrier_down_count
(4.16)

Signed-off-by: David Decotigny <decot@googlers.com>
[Florian:
* rebase
* add documentation
* merge carrier_changes with up/down counters]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/ABI/testing/sysfs-class-net b/Documentation/ABI/testing/sysfs-class-net
index 6856da9..2f17881 100644 (file)
--- a/Documentation/ABI/testing/sysfs-class-net
+++ b/Documentation/ABI/testing/sysfs-class-net
@@ -259,3 +259,27 @@ Contact:   netdev@vger.kernel.org
 Description:
                Symbolic link to the PHY device this network device is attached
                to.
+
+What:          /sys/class/net/<iface>/carrier_changes
+Date:          Mar 2014
+KernelVersion: 3.15
+Contact:       netdev@vger.kernel.org
+Description:
+               32-bit unsigned integer counting the number of times the link has
+               seen a change from UP to DOWN and vice versa
+
+What:          /sys/class/net/<iface>/carrier_up_count
+Date:          Jan 2018
+KernelVersion: 4.16
+Contact:       netdev@vger.kernel.org
+Description:
+               32-bit unsigned integer counting the number of times the link has
+               been up
+
+What:          /sys/class/net/<iface>/carrier_down_count
+Date:          Jan 2018
+KernelVersion: 4.16
+Contact:       netdev@vger.kernel.org
+Description:
+               32-bit unsigned integer counting the number of times the link has
+               been down

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ed0799a..837e9cb 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1680,8 +1680,6 @@ struct net_device {
        unsigned long           base_addr;
        int                     irq;
 
-       atomic_t                carrier_changes;
-
        /*
         *      Some hardware also needs these fields (state,dev_list,
         *      napi_list,unreg_list,close_list) but they are not
@@ -1719,6 +1717,10 @@ struct net_device {
        atomic_long_t           tx_dropped;
        atomic_long_t           rx_nohandler;
 
+       /* Stats to monitor link on/off, flapping */
+       atomic_t                carrier_up_count;
+       atomic_t                carrier_down_count;
+
 #ifdef CONFIG_WIRELESS_EXT
        const struct iw_handler_def *wireless_handlers;
        struct iw_public_data   *wireless_data;

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index f8f04fe..8616131 100644 (file)
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -161,6 +161,8 @@ enum {
        IFLA_EVENT,
        IFLA_NEW_NETNSID,
        IFLA_IF_NETNSID,
+       IFLA_CARRIER_UP_COUNT,
+       IFLA_CARRIER_DOWN_COUNT,
        __IFLA_MAX
 };
 

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 7bf8b85..c4a28f4 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -295,10 +295,31 @@ static ssize_t carrier_changes_show(struct device *dev,
        struct net_device *netdev = to_net_dev(dev);
 
        return sprintf(buf, fmt_dec,
-                      atomic_read(&netdev->carrier_changes));
+                      atomic_read(&netdev->carrier_up_count) +
+                      atomic_read(&netdev->carrier_down_count));
 }
 static DEVICE_ATTR_RO(carrier_changes);
 
+static ssize_t carrier_up_count_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_up_count));
+}
+static DEVICE_ATTR_RO(carrier_up_count);
+
+static ssize_t carrier_down_count_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_down_count));
+}
+static DEVICE_ATTR_RO(carrier_down_count);
+
 /* read-write attributes */
 
 static int change_mtu(struct net_device *dev, unsigned long new_mtu)
@@ -547,6 +568,8 @@ static struct attribute *net_class_attrs[] __ro_after_init = {
        &dev_attr_phys_port_name.attr,
        &dev_attr_phys_switch_id.attr,
        &dev_attr_proto_down.attr,
+       &dev_attr_carrier_up_count.attr,
+       &dev_attr_carrier_down_count.attr,
        NULL,
 };
 ATTRIBUTE_GROUPS(net_class);

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 16d644a..97874da 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -990,6 +990,8 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
               + nla_total_size(4)  /* IFLA_NEW_NETNSID */
               + nla_total_size(1)  /* IFLA_PROTO_DOWN */
               + nla_total_size(4)  /* IFLA_IF_NETNSID */
+              + nla_total_size(4)  /* IFLA_CARRIER_UP_COUNT */
+              + nla_total_size(4)  /* IFLA_CARRIER_DOWN_COUNT */
               + 0;
 }
 
@@ -1551,8 +1553,13 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
             nla_put_string(skb, IFLA_QDISC, dev->qdisc->ops->id)) ||
            nla_put_ifalias(skb, dev) ||
            nla_put_u32(skb, IFLA_CARRIER_CHANGES,
-                       atomic_read(&dev->carrier_changes)) ||
-           nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down))
+                       atomic_read(&dev->carrier_up_count) +
+                       atomic_read(&dev->carrier_down_count)) ||
+           nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down) ||
+           nla_put_u32(skb, IFLA_CARRIER_UP_COUNT,
+                       atomic_read(&dev->carrier_up_count)) ||
+           nla_put_u32(skb, IFLA_CARRIER_DOWN_COUNT,
+                       atomic_read(&dev->carrier_down_count)))
                goto nla_put_failure;
 
        if (event != IFLA_EVENT_NONE) {
@@ -1656,6 +1663,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
        [IFLA_EVENT]            = { .type = NLA_U32 },
        [IFLA_GROUP]            = { .type = NLA_U32 },
        [IFLA_IF_NETNSID]       = { .type = NLA_S32 },
+       [IFLA_CARRIER_UP_COUNT] = { .type = NLA_U32 },
+       [IFLA_CARRIER_DOWN_COUNT] = { .type = NLA_U32 },
 };
 
 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 ef8b4ec..1816bde 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -510,7 +510,7 @@ 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);
+               atomic_inc(&dev->carrier_up_count);
                linkwatch_fire_event(dev);
                if (netif_running(dev))
                        __netdev_watchdog_up(dev);
@@ -529,7 +529,7 @@ 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);
+               atomic_inc(&dev->carrier_down_count);
                linkwatch_fire_event(dev);
        }
 }