From 9ab3d9a3c24ee7132d85f5874f35ea5cb98b1588 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Mon, 23 Nov 2009 12:25:08 -0800
Subject: [PATCH] netdev: New function netdev_get_ifindex().

sFlow needs the ifindex of an interface, so this commit adds a function
to retrieve it.
---
 lib/netdev-linux.c    | 13 +++++++++++++
 lib/netdev-provider.h | 10 ++++++++++
 lib/netdev.c          | 15 +++++++++++++++
 lib/netdev.h          |  1 +
 4 files changed, 39 insertions(+)

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 3ccd6be9..b8e8015d 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -548,6 +548,17 @@ netdev_linux_get_mtu(const struct netdev *netdev_, int *mtup)
     return 0;
 }
 
+/* Returns the ifindex of 'netdev', if successful, as a positive number.
+ * On failure, returns a negative errno value. */
+static int
+netdev_linux_get_ifindex(const struct netdev *netdev)
+{
+    int ifindex, error;
+
+    error = get_ifindex(netdev, &ifindex);
+    return error ? -error : ifindex;
+}
+
 static int
 netdev_linux_get_carrier(const struct netdev *netdev_, bool *carrier)
 {
@@ -1388,6 +1399,7 @@ const struct netdev_class netdev_linux_class = {
     netdev_linux_set_etheraddr,
     netdev_linux_get_etheraddr,
     netdev_linux_get_mtu,
+    netdev_linux_get_ifindex,
     netdev_linux_get_carrier,
     netdev_linux_get_stats,
 
@@ -1432,6 +1444,7 @@ const struct netdev_class netdev_tap_class = {
     netdev_linux_set_etheraddr,
     netdev_linux_get_etheraddr,
     netdev_linux_get_mtu,
+    netdev_linux_get_ifindex,
     netdev_linux_get_carrier,
     netdev_linux_get_stats,
 
diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h
index 3bc7fd44..e013e202 100644
--- a/lib/netdev-provider.h
+++ b/lib/netdev-provider.h
@@ -164,6 +164,16 @@ struct netdev_class {
      * 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);
diff --git a/lib/netdev.c b/lib/netdev.c
index 965bdbf6..222342fd 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -366,6 +366,21 @@ netdev_get_mtu(const struct netdev *netdev, int *mtup)
     return error;
 }
 
+/* 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
+netdev_get_ifindex(const struct netdev *netdev)
+{
+    return netdev->class->get_ifindex(netdev);
+}
+
 /* Stores the features supported by 'netdev' into each of '*current',
  * '*advertised', '*supported', and '*peer' that are non-null.  Each value is a
  * bitmap of "enum ofp_port_features" bits, in host byte order.  Returns 0 if
diff --git a/lib/netdev.h b/lib/netdev.h
index 4a29cf37..b87d5b99 100644
--- a/lib/netdev.h
+++ b/lib/netdev.h
@@ -90,6 +90,7 @@ int netdev_enumerate(struct svec *);
 
 const char *netdev_get_name(const struct netdev *);
 int netdev_get_mtu(const struct netdev *, int *mtup);
+int netdev_get_ifindex(const struct netdev *);
 
 int netdev_recv(struct netdev *, struct ofpbuf *);
 void netdev_recv_wait(struct netdev *);
-- 
2.30.2