* bytes for Ethernet devices.*/
int (*get_mtu)(const struct netdev *, int *mtup);
+ /* Returns the ifindex of 'netdev', if successful, as a positive number.
+ * On failure, returns a negative errno value.
+ *
+ * The desired semantics of the ifindex value are a combination of those
+ * specified by POSIX for if_nametoindex() and by SNMP for ifIndex. An
+ * ifindex value should be unique within a host and remain stable at least
+ * until reboot. SNMP says an ifindex "ranges between 1 and the value of
+ * ifNumber" but many systems do not follow this rule anyhow. */
+ int (*get_ifindex)(const struct netdev *);
+
/* Sets 'carrier' to true if carrier is active (link light is on) on
* 'netdev'. */
int (*get_carrier)(const struct netdev *netdev, bool *carrier);