/
bridge_linux.go
100 lines (79 loc) · 2.42 KB
/
bridge_linux.go
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package devices
import (
"fmt"
"math/rand"
"net"
"sync"
"time"
"github.com/vishvananda/netlink"
)
var rnd = rand.New(rand.NewSource(time.Now().UnixNano()))
// netlink is not thread-safe, all calls to netlink should be guarded by this mutex
var netlinkMu *sync.Mutex = new(sync.Mutex)
type Bridge struct{}
// Create creates a bridge device and returns the interface.
// If the device already exists, returns the existing interface.
func (Bridge) Create(name string, ip net.IP, subnet *net.IPNet) (intf *net.Interface, err error) {
netlinkMu.Lock()
defer netlinkMu.Unlock()
if intf, _ := net.InterfaceByName(name); intf != nil {
return intf, nil
}
link := &netlink.Bridge{LinkAttrs: netlink.LinkAttrs{Name: name}}
if err := netlink.LinkAdd(link); err != nil && err.Error() != "file exists" {
return nil, fmt.Errorf("devices: create bridge: %v", err)
}
if err := netlink.BridgeSetMcastSnoop(link, false); err != nil {
return nil, fmt.Errorf("devices: disable multicast snooping: %v", err)
}
hAddr, _ := net.ParseMAC(randMacAddr())
err = netlink.LinkSetHardwareAddr(link, hAddr)
if err != nil {
return nil, fmt.Errorf("devices: set hardware address: %v", err)
}
if intf, err = net.InterfaceByName(name); err != nil {
return nil, fmt.Errorf("devices: look up created bridge interface: %v", err)
}
addr := &netlink.Addr{IPNet: &net.IPNet{IP: ip, Mask: subnet.Mask}}
if err = netlink.AddrAdd(link, addr); err != nil && err.Error() != "file exists" {
return nil, fmt.Errorf("devices: add IP to bridge: %v", err)
}
return intf, nil
}
func (Bridge) Add(bridge, slaveIf *net.Interface) error {
netlinkMu.Lock()
defer netlinkMu.Unlock()
master, err := netlink.LinkByName(bridge.Name)
if err != nil {
return err
}
slave, err := netlink.LinkByName(slaveIf.Name)
if err != nil {
return err
}
return netlink.LinkSetMaster(slave, master.(*netlink.Bridge))
}
func (Bridge) Destroy(bridge string) error {
netlinkMu.Lock()
defer netlinkMu.Unlock()
intfs, err := net.Interfaces()
if err != nil {
return err
}
for _, i := range intfs {
if i.Name == bridge {
link := &netlink.Bridge{LinkAttrs: netlink.LinkAttrs{Name: bridge}}
return netlink.LinkDel(link)
}
}
return nil
}
func randMacAddr() string {
hw := make(net.HardwareAddr, 6)
for i := 0; i < 6; i++ {
hw[i] = byte(rnd.Intn(255))
}
hw[0] &^= 0x1 // clear multicast bit
hw[0] |= 0x2 // set local assignment bit (IEEE802)
return hw.String()
}