From 085dc47dcc1f6ee8dc441b96d2eab9a376d36c6e Mon Sep 17 00:00:00 2001
From: Dave Tucker <dave@dtucker.co.uk>
Date: Sat, 31 Jan 2015 19:55:10 +0000
Subject: [PATCH] Add LinkSetName

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
---
 link_linux.go | 21 +++++++++++++++++++++
 link_test.go  | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/link_linux.go b/link_linux.go
index bac8349..98a6515 100644
--- a/link_linux.go
+++ b/link_linux.go
@@ -80,6 +80,27 @@ func LinkSetMTU(link Link, mtu int) error {
 	return err
 }
 
+// LinkSetName sets the name of the link device.
+// Equivalent to: `ip link set $link name $name`
+func LinkSetName(link Link, name string) error {
+	base := link.Attrs()
+	ensureIndex(base)
+	req := nl.NewNetlinkRequest(syscall.RTM_SETLINK, syscall.NLM_F_ACK)
+
+	msg := nl.NewIfInfomsg(syscall.AF_UNSPEC)
+	msg.Type = syscall.RTM_SETLINK
+	msg.Flags = syscall.NLM_F_REQUEST
+	msg.Index = int32(base.Index)
+	msg.Change = nl.DEFAULT_CHANGE
+	req.AddData(msg)
+
+	data := nl.NewRtAttr(syscall.IFLA_IFNAME, []byte(name))
+	req.AddData(data)
+
+	_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
+	return err
+}
+
 // LinkSetMaster sets the master of the link device.
 // Equivalent to: `ip link set $link master $master`
 func LinkSetMaster(link Link, master *Bridge) error {
diff --git a/link_test.go b/link_test.go
index 232ad03..8e58804 100644
--- a/link_test.go
+++ b/link_test.go
@@ -399,3 +399,42 @@ func TestLinkByIndex(t *testing.T) {
 		t.Fatalf("LinkByIndex(%v) found deleted link", err)
 	}
 }
+
+func TestLinkSet(t *testing.T) {
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	iface := &Dummy{LinkAttrs{Name: "foo"}}
+	if err := LinkAdd(iface); err != nil {
+		t.Fatal(err)
+	}
+
+	link, err := LinkByName("foo")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = LinkSetName(link, "bar")
+	if err != nil {
+		t.Fatalf("Could not change interface name: %v", err)
+	}
+
+	link, err = LinkByName("bar")
+	if err != nil {
+		t.Fatalf("Interface name not changed: %v", err)
+	}
+
+	err = LinkSetMTU(link, 1400)
+	if err != nil {
+		t.Fatalf("Could not set MTU: %v", err)
+	}
+
+	link, err = LinkByName("bar")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if link.Attrs().MTU != 1400 {
+		t.Fatal("MTU not changed!")
+	}
+}