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|
package network
import (
"errors"
"net"
"syscall"
"github.com/vishvananda/netlink"
)
//GetDefaultGateway return default gateway of the network namespace
func GetDefaultGateway() (string, error) {
routes, err := netlink.RouteList(nil, syscall.AF_INET)
if err != nil {
return "", err
}
for _, route := range routes {
if route.Dst == nil || route.Dst.String() == "0.0.0.0/0" {
if route.Gw.To4() == nil {
return "", errors.New("Found default route but could not determine gateway")
}
return route.Gw.To4().String(), nil
}
}
return "", errors.New("Unable to find default route")
}
//CheckRoute return bool isPresent
func CheckRoute(dst, gw string) (bool, error) {
var isPresent bool
routes, err := netlink.RouteList(nil, syscall.AF_INET)
if err != nil {
return isPresent, err
}
for _, route := range routes {
if route.Dst.String() == dst && route.Gw.To4().String() == gw {
isPresent = true
}
}
return isPresent, nil
}
// GetDefaultGatewayInterface return default gateway interface link
func GetDefaultGatewayInterface() (*net.Interface, error) {
routes, err := netlink.RouteList(nil, syscall.AF_INET)
if err != nil {
return nil, err
}
for _, route := range routes {
if route.Dst == nil || route.Dst.String() == "0.0.0.0/0" {
if route.LinkIndex <= 0 {
return nil, errors.New("Found default route but could not determine interface")
}
return net.InterfaceByIndex(route.LinkIndex)
}
}
return nil, errors.New("Unable to find default route")
}
func getIfaceAddrs(iface *net.Interface) ([]netlink.Addr, error) {
link := &netlink.Device{
netlink.LinkAttrs{
Index: iface.Index,
},
}
return netlink.AddrList(link, syscall.AF_INET)
}
//GetInterfaceIP4Addr return IP4addr of a interface
func GetInterfaceIP4Addr(iface *net.Interface) (netlink.Addr, error) {
addrs, err := getIfaceAddrs(iface)
if err != nil {
return netlink.Addr{}, err
}
// prefer non link-local addr
var ll netlink.Addr
for _, addr := range addrs {
if addr.IP.To4() == nil {
continue
}
if addr.IP.IsGlobalUnicast() {
return addr, nil
}
if addr.IP.IsLinkLocalUnicast() {
ll = addr
}
}
if ll.IP.To4() != nil {
// didn't find global but found link-local. it'll do.
return ll, nil
}
return netlink.Addr{}, errors.New("No IPv4 address found for given interface")
}
//GetHostNetwork return default gateway interface network
func GetHostNetwork() (string, error) {
iface, err := GetDefaultGatewayInterface()
if err != nil {
log.Error(err, "error in gettting default gateway interface")
return "", err
}
ipv4addr, err := GetInterfaceIP4Addr(iface)
if err != nil {
log.Error(err, "error in gettting default gateway interface IPv4 address")
return "", err
}
_, ipv4Net, err := net.ParseCIDR(ipv4addr.IPNet.String())
if err != nil {
log.Error(err, "error in gettting default gateway interface network")
return "", err
}
return ipv4Net.String(), nil
}
|
