AdGuardHome/dhcpd/standalone/main.go

116 lines
2.4 KiB
Go

package main
import (
"net"
"os"
"os/signal"
"syscall"
"time"
"github.com/AdguardTeam/AdGuardHome/dhcpd"
"github.com/AdguardTeam/golibs/log"
"github.com/krolaw/dhcp4"
)
func main() {
if len(os.Args) < 2 {
log.Printf("Usage: %s <interface name>", os.Args[0])
os.Exit(64)
}
ifaceName := os.Args[1]
present, err := dhcpd.CheckIfOtherDHCPServersPresent(ifaceName)
if err != nil {
panic(err)
}
log.Printf("Found DHCP server? %v", present)
if present {
log.Printf("Will not start DHCP server because there's already running one on the network")
os.Exit(1)
}
iface, err := net.InterfaceByName(ifaceName)
if err != nil {
panic(err)
}
// get ipv4 address of an interface
ifaceIPNet := getIfaceIPv4(iface)
if ifaceIPNet == nil {
panic(err)
}
// append 10 to server's IP address as start
start := dhcp4.IPAdd(ifaceIPNet.IP, 10)
// lease range is 100 IP's, but TODO: don't go beyond end of subnet mask
stop := dhcp4.IPAdd(start, 100)
server := dhcpd.Server{}
config := dhcpd.ServerConfig{
InterfaceName: ifaceName,
RangeStart: start.String(),
RangeEnd: stop.String(),
SubnetMask: "255.255.255.0",
GatewayIP: "192.168.7.1",
}
log.Printf("Starting DHCP server")
err = server.Init(config)
if err != nil {
panic(err)
}
err = server.Start()
if err != nil {
panic(err)
}
time.Sleep(time.Second)
log.Printf("Stopping DHCP server")
err = server.Stop()
if err != nil {
panic(err)
}
log.Printf("Starting DHCP server")
err = server.Start()
if err != nil {
panic(err)
}
log.Printf("Starting DHCP server while it's already running")
err = server.Start()
if err != nil {
panic(err)
}
log.Printf("Now serving DHCP")
signalChannel := make(chan os.Signal)
signal.Notify(signalChannel, syscall.SIGINT, syscall.SIGTERM)
<-signalChannel
}
// return first IPv4 address of an interface, if there is any
func getIfaceIPv4(iface *net.Interface) *net.IPNet {
ifaceAddrs, err := iface.Addrs()
if err != nil {
panic(err)
}
for _, addr := range ifaceAddrs {
ipnet, ok := addr.(*net.IPNet)
if !ok {
// not an IPNet, should not happen
log.Fatalf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet", addr)
}
if ipnet.IP.To4() == nil {
log.Printf("Got IP that is not IPv4: %v", ipnet.IP)
continue
}
log.Printf("Got IP that is IPv4: %v", ipnet.IP)
return &net.IPNet{
IP: ipnet.IP.To4(),
Mask: ipnet.Mask,
}
}
return nil
}