107 lines
2.8 KiB
Go
107 lines
2.8 KiB
Go
package net
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
"syscall"
|
|
|
|
"github.com/vishvananda/netlink"
|
|
)
|
|
|
|
// Wait for an interface to come up.
|
|
func EnsureInterface(ifaceName string) (*net.Interface, error) {
|
|
iface, err := ensureInterface(ifaceName)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return iface, err
|
|
}
|
|
|
|
func ensureInterface(ifaceName string) (*net.Interface, error) {
|
|
ch := make(chan netlink.LinkUpdate)
|
|
// NB: We do not supply (and eventually close) a 'done' channel
|
|
// here since that can cause incorrect file descriptor
|
|
// re-usage. See https://github.com/weaveworks/weave/issues/2120
|
|
if err := netlink.LinkSubscribe(ch, nil); err != nil {
|
|
return nil, err
|
|
}
|
|
// check for currently-existing interface after subscribing, to avoid race
|
|
if iface, err := findInterface(ifaceName); err == nil {
|
|
return iface, nil
|
|
}
|
|
for update := range ch {
|
|
if ifaceName == update.Link.Attrs().Name && update.IfInfomsg.Flags&syscall.IFF_UP != 0 {
|
|
break
|
|
}
|
|
}
|
|
iface, err := findInterface(ifaceName)
|
|
return iface, err
|
|
}
|
|
|
|
// Wait for an interface to come up and have a route added to the multicast subnet.
|
|
// This matches the behaviour in 'weave attach', which is the only context in which
|
|
// we expect this to be called. If you change one, change the other to match.
|
|
func EnsureInterfaceAndMcastRoute(ifaceName string) (*net.Interface, error) {
|
|
iface, err := ensureInterface(ifaceName)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
ch := make(chan netlink.RouteUpdate)
|
|
if err := netlink.RouteSubscribe(ch, nil); err != nil {
|
|
return nil, err
|
|
}
|
|
dest := net.IPv4(224, 0, 0, 0)
|
|
check := func(route netlink.Route) bool {
|
|
return route.Dst != nil && route.Dst.IP.Equal(dest)
|
|
}
|
|
// check for currently-existing route after subscribing, to avoid race
|
|
routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
for _, route := range routes {
|
|
if check(route) {
|
|
return iface, nil
|
|
}
|
|
}
|
|
for update := range ch {
|
|
if check(update.Route) {
|
|
return iface, nil
|
|
}
|
|
}
|
|
// should never get here
|
|
return iface, nil
|
|
}
|
|
|
|
func findInterface(ifaceName string) (iface *net.Interface, err error) {
|
|
if iface, err = net.InterfaceByName(ifaceName); err != nil {
|
|
return iface, fmt.Errorf("Unable to find interface %s", ifaceName)
|
|
}
|
|
if 0 == (net.FlagUp & iface.Flags) {
|
|
return iface, fmt.Errorf("Interface %s is not up", ifaceName)
|
|
}
|
|
return
|
|
}
|
|
|
|
func LocalAddresses() ([]*net.IPNet, error) {
|
|
links, err := netlink.LinkList()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
retval := []*net.IPNet{}
|
|
for _, link := range links {
|
|
if _, isBridge := link.(*netlink.Bridge); isBridge || (link.Attrs().Flags&net.FlagLoopback) != 0 {
|
|
continue
|
|
}
|
|
addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
for _, addr := range addrs {
|
|
retval = append(retval, addr.IPNet)
|
|
}
|
|
}
|
|
return retval, nil
|
|
}
|