[PATCH 2/4] interface_backend_udev: Implement link speed & state

[Michal Privoznik <mprivozn@xxxxxxxxxx>]

In previous commit the interface XML is prepared for exporting
information on NIC link speed and state. This commit implement
actual logic for getting such info and writing it into XML.

Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
---

Notes:
    For the kernel issue I've posted patch here:
    
    http://patchwork.ozlabs.org/patch/354928/
    
    But it wasn't accepted as developers are afraid of breaking backward
    compatibility. Which is weird as in 2.6.X the kernel was reporting -1
    instead of unsigned -1.

 src/interface/interface_backend_udev.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/interface/interface_backend_udev.c b/src/interface/interface_backend_udev.c
index c5353ea..80ba93e 100644
--- a/src/interface/interface_backend_udev.c
+++ b/src/interface/interface_backend_udev.c
@@ -1036,6 +1036,8 @@ udevGetIfaceDef(struct udev *udev, const char *name)
     const char *mtu_str;
     char *vlan_parent_dev = NULL;
     const char *devtype;
+    const char *operstate;
+    const char *link_speed;
 
     /* Allocate our interface definition structure */
     if (VIR_ALLOC(ifacedef) < 0)
@@ -1059,6 +1061,31 @@ udevGetIfaceDef(struct udev *udev, const char *name)
                    udev_device_get_sysattr_value(dev, "address")) < 0)
         goto error;
 
+    operstate = udev_device_get_sysattr_value(dev, "operstate");
+    if ((ifacedef->lnk.state = virInterfaceStateTypeFromString(operstate)) <= 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Unable to parse operstate: %s"),
+                       operstate);
+        goto error;
+    }
+
+    link_speed = udev_device_get_sysattr_value(dev, "speed");
+    if (link_speed) {
+        if (virStrToLong_ul(link_speed, NULL, 10, &ifacedef->lnk.speed) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("Unable to parse speed: %s"),
+                           link_speed);
+            goto error;
+        }
+
+        /* Workaround broken kernel API. If the link is unplugged then
+         * depending on the NIC driver, link speed can be reported as -1.
+         * However, the value is printed out as unsigned integer instead of
+         * signed one. Terrifying but true. */
+        if ((int) ifacedef->lnk.speed == -1)
+            ifacedef->lnk.speed = 0;
+    }
+
     /* MTU */
     mtu_str = udev_device_get_sysattr_value(dev, "mtu");
     if (virStrToLong_ui(mtu_str, NULL, 10, &mtu) < 0) {
-- 
2.0.0

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