93 lines
3.0 KiB
Markdown
93 lines
3.0 KiB
Markdown
|
# netlink - netlink library for go #
|
||
|
|
|
||
|
|
[](https://travis-ci.org/vishvananda/netlink) [](https://godoc.org/github.com/vishvananda/netlink)
|
||
|
|
|
||
|
|
The netlink package provides a simple netlink library for go. Netlink
|
||
|
|
is the interface a user-space program in linux uses to communicate with
|
||
|
|
the kernel. It can be used to add and remove interfaces, set ip addresses
|
||
|
|
and routes, and configure ipsec. Netlink communication requires elevated
|
||
|
|
privileges, so in most cases this code needs to be run as root. Since
|
||
|
|
low-level netlink messages are inscrutable at best, the library attempts
|
||
|
|
to provide an api that is loosely modeled on the CLI provided by iproute2.
|
||
|
|
Actions like `ip link add` will be accomplished via a similarly named
|
||
|
|
function like AddLink(). This library began its life as a fork of the
|
||
|
|
netlink functionality in
|
||
|
|
[docker/libcontainer](https://github.com/docker/libcontainer) but was
|
||
|
|
heavily rewritten to improve testability, performance, and to add new
|
||
|
|
functionality like ipsec xfrm handling.
|
||
|
|
|
||
|
|
## Local Build and Test ##
|
||
|
|
|
||
|
|
You can use go get command:
|
||
|
|
|
||
|
|
go get github.com/vishvananda/netlink
|
||
|
|
|
||
|
|
Testing dependencies:
|
||
|
|
|
||
|
|
go get github.com/vishvananda/netns
|
||
|
|
|
||
|
|
Testing (requires root):
|
||
|
|
|
||
|
|
sudo -E go test github.com/vishvananda/netlink
|
||
|
|
|
||
|
|
## Examples ##
|
||
|
|
|
||
|
|
Add a new bridge and add eth1 into it:
|
||
|
|
|
||
|
|
```go
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"github.com/vishvananda/netlink"
|
||
|
|
)
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
la := netlink.NewLinkAttrs()
|
||
|
|
la.Name = "foo"
|
||
|
|
mybridge := &netlink.Bridge{LinkAttrs: la}
|
||
|
|
err := netlink.LinkAdd(mybridge)
|
||
|
|
if err != nil {
|
||
|
|
fmt.Printf("could not add %s: %v\n", la.Name, err)
|
||
|
|
}
|
||
|
|
eth1, _ := netlink.LinkByName("eth1")
|
||
|
|
netlink.LinkSetMaster(eth1, mybridge)
|
||
|
|
}
|
||
|
|
|
||
|
|
```
|
||
|
|
Note `NewLinkAttrs` constructor, it sets default values in structure. For now
|
||
|
|
it sets only `TxQLen` to `-1`, so kernel will set default by itself. If you're
|
||
|
|
using simple initialization(`LinkAttrs{Name: "foo"}`) `TxQLen` will be set to
|
||
|
|
`0` unless you specify it like `LinkAttrs{Name: "foo", TxQLen: 1000}`.
|
||
|
|
|
||
|
|
Add a new ip address to loopback:
|
||
|
|
|
||
|
|
```go
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"github.com/vishvananda/netlink"
|
||
|
|
)
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
lo, _ := netlink.LinkByName("lo")
|
||
|
|
addr, _ := netlink.ParseAddr("169.254.169.254/32")
|
||
|
|
netlink.AddrAdd(lo, addr)
|
||
|
|
}
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
## Future Work ##
|
||
|
|
|
||
|
|
Many pieces of netlink are not yet fully supported in the high-level
|
||
|
|
interface. Aspects of virtually all of the high-level objects don't exist.
|
||
|
|
Many of the underlying primitives are there, so its a matter of putting
|
||
|
|
the right fields into the high-level objects and making sure that they
|
||
|
|
are serialized and deserialized correctly in the Add and List methods.
|
||
|
|
|
||
|
|
There are also a few pieces of low level netlink functionality that still
|
||
|
|
need to be implemented. Routing rules are not in place and some of the
|
||
|
|
more advanced link types. Hopefully there is decent structure and testing
|
||
|
|
in place to make these fairly straightforward to add.
|
||
|
|
|