1# netlink - netlink library for go #
2
3 [](https://godoc.org/github.com/vishvananda/netlink)
4
5The netlink package provides a simple netlink library for go. Netlink
6is the interface a user-space program in linux uses to communicate with
7the kernel. It can be used to add and remove interfaces, set ip addresses
8and routes, and configure ipsec. Netlink communication requires elevated
9privileges, so in most cases this code needs to be run as root. Since
10low-level netlink messages are inscrutable at best, the library attempts
11to provide an api that is loosely modeled on the CLI provided by iproute2.
12Actions like `ip link add` will be accomplished via a similarly named
13function like AddLink(). This library began its life as a fork of the
14netlink functionality in
15[docker/libcontainer](https://github.com/docker/libcontainer) but was
16heavily rewritten to improve testability, performance, and to add new
17functionality like ipsec xfrm handling.
18
19## Local Build and Test ##
20
21You can use go get command:
22
23 go get github.com/vishvananda/netlink
24
25Testing dependencies:
26
27 go get github.com/vishvananda/netns
28
29Testing (requires root):
30
31 sudo -E go test github.com/vishvananda/netlink
32
33## Examples ##
34
35Add a new bridge and add eth1 into it:
36
37```go
38package main
39
40import (
41 "fmt"
42 "github.com/vishvananda/netlink"
43)
44
45func main() {
46 la := netlink.NewLinkAttrs()
47 la.Name = "foo"
48 mybridge := &netlink.Bridge{LinkAttrs: la}
49 err := netlink.LinkAdd(mybridge)
50 if err != nil {
51 fmt.Printf("could not add %s: %v\n", la.Name, err)
52 }
53 eth1, _ := netlink.LinkByName("eth1")
54 netlink.LinkSetMaster(eth1, mybridge)
55}
56
57```
58Note `NewLinkAttrs` constructor, it sets default values in structure. For now
59it sets only `TxQLen` to `-1`, so kernel will set default by itself. If you're
60using simple initialization(`LinkAttrs{Name: "foo"}`) `TxQLen` will be set to
61`0` unless you specify it like `LinkAttrs{Name: "foo", TxQLen: 1000}`.
62
63Add a new ip address to loopback:
64
65```go
66package main
67
68import (
69 "github.com/vishvananda/netlink"
70)
71
72func main() {
73 lo, _ := netlink.LinkByName("lo")
74 addr, _ := netlink.ParseAddr("169.254.169.254/32")
75 netlink.AddrAdd(lo, addr)
76}
77
78```
79
80## Future Work ##
81
82Many pieces of netlink are not yet fully supported in the high-level
83interface. Aspects of virtually all of the high-level objects don't exist.
84Many of the underlying primitives are there, so its a matter of putting
85the right fields into the high-level objects and making sure that they
86are serialized and deserialized correctly in the Add and List methods.
87
88There are also a few pieces of low level netlink functionality that still
89need to be implemented. Routing rules are not in place and some of the
90more advanced link types. Hopefully there is decent structure and testing
91in place to make these fairly straightforward to add.
92
View as plain text