2019-03-15 09:39:28 +00:00

124 lines
3.5 KiB
Go

package clientport
import (
"errors"
"net"
"strings"
"github.com/coredhcp/coredhcp/handler"
"github.com/coredhcp/coredhcp/logger"
"github.com/coredhcp/coredhcp/plugins"
"github.com/insomniacslk/dhcp/dhcpv4"
"github.com/insomniacslk/dhcp/dhcpv6"
"github.com/insomniacslk/dhcp/iana"
)
var log = logger.GetLogger()
func init() {
plugins.RegisterPlugin("server_id", setupServerID6, setupServerID4)
}
// V6ServerID is the DUID of the v6 server
var (
V6ServerID *dhcpv6.Duid
V4ServerID net.IP
)
// Handler6 handles DHCPv6 packets for the server_id plugin.
func Handler6(req, resp dhcpv6.DHCPv6) (dhcpv6.DHCPv6, bool) {
if V6ServerID == nil {
return resp, false
}
if opt := req.GetOneOption(dhcpv6.OptionServerID); opt != nil {
sid := opt.(*dhcpv6.OptServerId)
if !sid.Sid.Equal(*V6ServerID) {
log.Infof("plugins/server_id: requested server ID does not match this server's ID. Got %v, want %v", sid.Sid, V6ServerID)
}
}
dhcpv6.WithServerID(*V6ServerID)(resp)
return resp, false
}
// Handler4 handles DHCPv4 packets for the server_id plugin.
func Handler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
if V4ServerID == nil || resp == nil {
return resp, false
}
if req.OpCode != dhcpv4.OpcodeBootRequest {
log.Warningf("plugins/server_id: not a BootRequest, ignoring")
return resp, false
}
if req.ServerIPAddr != nil &&
!req.ServerIPAddr.Equal(net.IPv4zero) &&
!req.ServerIPAddr.Equal(V4ServerID) {
// This request is not for us, drop it.
log.Infof("plugins/server_id: requested server ID does not match this server's ID. Got %v, want %v", req.ServerIPAddr, V4ServerID)
return nil, true
}
resp.ServerIPAddr = make(net.IP, net.IPv4len)
copy(resp.ServerIPAddr[:], V4ServerID)
return resp, false
}
func setupServerID4(args ...string) (handler.Handler4, error) {
log.Print("plugins/server_id: loading `server_id` plugin for DHCPv4")
if len(args) < 1 {
return nil, errors.New("plugins/server_id: need an argument")
}
serverID := net.ParseIP(args[0])
if serverID == nil {
return nil, errors.New("plugins/server_id: invalid or empty IP address")
}
if serverID.To4() == nil {
return nil, errors.New("plugins/server_id: not a valid IPv4 address")
}
V4ServerID = serverID
return Handler4, nil
}
func setupServerID6(args ...string) (handler.Handler6, error) {
log.Print("plugins/server_id: loading `server_id` plugin for DHCPv6")
if len(args) < 2 {
return nil, errors.New("plugins/server_id: need a DUID type and value")
}
duidType := args[0]
if duidType == "" {
return nil, errors.New("plugins/server_id: got empty DUID type")
}
duidValue := args[1]
if duidValue == "" {
return nil, errors.New("plugins/server_id: got empty DUID value")
}
duidType = strings.ToLower(duidType)
hwaddr, err := net.ParseMAC(duidValue)
if err != nil {
return nil, err
}
switch duidType {
case "ll", "duid-ll", "duid_ll":
V6ServerID = &dhcpv6.Duid{
Type: dhcpv6.DUID_LL,
// sorry, only ethernet for now
HwType: iana.HWTypeEthernet,
LinkLayerAddr: hwaddr,
}
case "llt", "duid-llt", "duid_llt":
V6ServerID = &dhcpv6.Duid{
Type: dhcpv6.DUID_LLT,
// sorry, zero-time for now
Time: 0,
// sorry, only ethernet for now
HwType: iana.HWTypeEthernet,
LinkLayerAddr: hwaddr,
}
case "en", "uuid":
return nil, errors.New("EN/UUID DUID type not supported yet")
default:
return nil, errors.New("Opaque DUID type not supported yet")
}
log.Printf("plugins/server_id: using %s %s", duidType, duidValue)
return Handler6, nil
}