func main() {
// glog will log to tmp files by default. override so all entries
// can flow into journald (if running under systemd)
flag.Set("logtostderr", "true")
// now parse command line args
flag.Parse()
if opts.help {
fmt.Fprintf(os.Stderr, "Usage: %s [OPTION]...\n", os.Args[0])
flag.PrintDefaults()
os.Exit(0)
}
if opts.version {
fmt.Fprintln(os.Stderr, Version)
os.Exit(0)
}
iface, tep := lookupIface()
if iface == nil || tep == nil {
return
}
log.Infof("Using %s to tunnel", tep)
sm := makeSubnetManager()
udp.Run(sm, iface, tep, opts.port, opts.ipMasq, func(sn ip.IP4Net, mtu int) {
writeSubnet(sn, mtu)
daemon.SdNotify("READY=1")
})
}
func (sm *SubnetManager) allocateSubnet() (ip.IP4Net, error) {
log.Infof("Picking subnet in range %s ... %s", sm.config.SubnetMin, sm.config.SubnetMax)
var bag []ip.IP4
sn := ip.IP4Net{IP: sm.config.SubnetMin, PrefixLen: sm.config.SubnetLen}
OuterLoop:
for ; sn.IP <= sm.config.SubnetMax && len(bag) < 100; sn = sn.Next() {
for _, l := range sm.leases {
if sn.Overlaps(l.Network) {
continue OuterLoop
}
}
bag = append(bag, sn.IP)
}
if len(bag) == 0 {
return ip.IP4Net{}, errors.New("out of subnets")
} else {
i := randInt(0, len(bag))
return ip.IP4Net{IP: bag[i], PrefixLen: sm.config.SubnetLen}, nil
}
}
