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// +build go1.12
package server4
import (
"context"
"log"
"math/rand"
"net"
"testing"
"time"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/insomniacslk/dhcp/dhcpv4/nclient4"
"github.com/insomniacslk/dhcp/interfaces"
"github.com/stretchr/testify/require"
)
func init() {
// initialize seed. This is generally bad, but "good enough"
// to generate random ports for these tests
rand.Seed(time.Now().UTC().UnixNano())
}
func randPort() int {
// can't use port 0 with raw sockets, so until we implement
// a non-raw-sockets client for non-static ports, we have to
// deal with this "randomness"
return 32*1024 + rand.Intn(65536-32*1024)
}
// DORAHandler is a server handler suitable for DORA transactions
func DORAHandler(conn net.PacketConn, peer net.Addr, m *dhcpv4.DHCPv4) {
if m == nil {
log.Printf("Packet is nil!")
return
}
if m.OpCode != dhcpv4.OpcodeBootRequest {
log.Printf("Not a BootRequest!")
return
}
reply, err := dhcpv4.NewReplyFromRequest(m)
if err != nil {
log.Printf("NewReplyFromRequest failed: %v", err)
return
}
reply.UpdateOption(dhcpv4.OptServerIdentifier(net.IP{1, 2, 3, 4}))
switch mt := m.MessageType(); mt {
case dhcpv4.MessageTypeDiscover:
reply.UpdateOption(dhcpv4.OptMessageType(dhcpv4.MessageTypeOffer))
case dhcpv4.MessageTypeRequest:
reply.UpdateOption(dhcpv4.OptMessageType(dhcpv4.MessageTypeAck))
default:
log.Printf("Unhandled message type: %v", mt)
return
}
if _, err := conn.WriteTo(reply.ToBytes(), peer); err != nil {
log.Printf("Cannot reply to client: %v", err)
}
}
// utility function to set up a client and a server instance and run it in
// background. The caller needs to call Server.Close() once finished.
func setUpClientAndServer(t *testing.T, iface net.Interface, handler Handler) (*nclient4.Client, *Server) {
// strong assumption, I know
loAddr := net.ParseIP("127.0.0.1")
saddr := net.UDPAddr{
IP: loAddr,
Port: randPort(),
}
caddr := net.UDPAddr{
IP: loAddr,
Port: randPort(),
}
s, err := NewServer(&saddr, handler)
if err != nil {
t.Fatal(err)
}
go func() {
_ = s.Serve()
}()
clientConn, err := nclient4.NewIPv4UDPConn("", caddr.Port)
if err != nil {
t.Fatal(err)
}
c, err := nclient4.NewWithConn(clientConn, iface.HardwareAddr, nclient4.WithServerAddr(&saddr))
if err != nil {
t.Fatal(err)
}
return c, s
}
func TestServer(t *testing.T) {
ifaces, err := interfaces.GetLoopbackInterfaces()
require.NoError(t, err)
require.NotEqual(t, 0, len(ifaces))
// lo has a HardwareAddr of "nil". The client will drop all packets
// that don't match the HWAddr of the client interface.
hwaddr := net.HardwareAddr{1, 2, 3, 4, 5, 6}
ifaces[0].HardwareAddr = hwaddr
c, s := setUpClientAndServer(t, ifaces[0], DORAHandler)
defer func() {
require.Nil(t, s.Close())
}()
xid := dhcpv4.TransactionID{0xaa, 0xbb, 0xcc, 0xdd}
modifiers := []dhcpv4.Modifier{
dhcpv4.WithTransactionID(xid),
dhcpv4.WithHwAddr(ifaces[0].HardwareAddr),
}
offer, ack, err := c.Request(context.Background(), modifiers...)
require.NoError(t, err)
require.NotNil(t, offer, ack)
for _, p := range []*dhcpv4.DHCPv4{offer, ack} {
require.Equal(t, xid, p.TransactionID)
require.Equal(t, ifaces[0].HardwareAddr, p.ClientHWAddr)
}
}
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