/
ugsx.go
68 lines (63 loc) · 1.62 KB
/
ugsx.go
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package killswitch
import (
"errors"
"net"
"syscall"
"golang.org/x/net/route"
)
// UGSH, UGSc man netstat
const (
UGSH = syscall.RTF_UP | syscall.RTF_GATEWAY | syscall.RTF_STATIC | syscall.RTF_HOST
UGSc = syscall.RTF_UP | syscall.RTF_GATEWAY | syscall.RTF_STATIC | syscall.RTF_PRCLONING
)
func privateIP(ip string) (bool, error) {
var err error
private := false
IP := net.ParseIP(ip)
if IP == nil {
err = errors.New("Invalid IP")
} else {
_, private24BitBlock, _ := net.ParseCIDR("10.0.0.0/8")
_, private20BitBlock, _ := net.ParseCIDR("172.16.0.0/12")
_, private16BitBlock, _ := net.ParseCIDR("192.168.0.0/16")
private = private24BitBlock.Contains(IP) || private20BitBlock.Contains(IP) || private16BitBlock.Contains(IP)
}
return private, err
}
// UGSX find IP of the vpn by matching existing route flags, man netstat
func UGSX() (net.IP, error) {
rib, err := route.FetchRIB(syscall.AF_UNSPEC, route.RIBTypeRoute, 0)
if err != nil {
return nil, err
}
msgs, err := route.ParseRIB(route.RIBTypeRoute, rib)
if err != nil {
return nil, err
}
var ip net.IP
for _, msg := range msgs {
m := msg.(*route.RouteMessage)
if m.Flags == UGSH || m.Flags == UGSc {
switch a := m.Addrs[syscall.AF_UNSPEC].(type) {
case *route.Inet4Addr:
ip = net.IPv4(a.IP[0], a.IP[1], a.IP[2], a.IP[3])
case *route.Inet6Addr:
ip = make(net.IP, net.IPv6len)
copy(ip, a.IP[:])
}
if ok, err := privateIP(ip.String()); err != nil {
continue
} else if !ok {
switch ip.String() {
case "0.0.0.0":
continue
case "128.0.0.0":
continue
default:
return ip, nil
}
}
}
}
return ip, nil
}