124 lines
2.5 KiB
Go
124 lines
2.5 KiB
Go
package server
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import (
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"errors"
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"net"
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"time"
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log "git.wntrmute.dev/kyle/goutils/syslog"
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"git.wntrmute.dev/kyle/kdhcp/config"
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"git.wntrmute.dev/kyle/kdhcp/dhcp"
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"git.wntrmute.dev/kyle/kdhcp/iptools"
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)
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const (
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DefaultPool = "default"
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MaxPacketSize = 512
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MaxResponseWait = 5 * time.Minute
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)
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type Server struct {
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Conn net.PacketConn
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Config *config.Config
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Pools map[string]*iptools.Pool
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Static map[string]*iptools.LeaseInfo
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}
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func (s *Server) Close() error {
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return s.Conn.Close()
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}
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func (s *Server) Bind() (err error) {
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// In order to read DHCP packets, we'll need to listen on all addresses.
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// That being said, we also want to limit our listening to the DHCP
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// network device.
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ip := net.IP([]byte{0, 0, 0, 0})
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s.Conn, err = BindInterface(ip, s.Config.Port, s.Config.Interface)
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return err
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}
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func (s *Server) ReadFrom() ([]byte, net.Addr, error) {
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b := make([]byte, MaxPacketSize)
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n, addr, err := s.Conn.ReadFrom(b)
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if err != nil {
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return nil, nil, err
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}
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b = b[:n]
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return b, addr, nil
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}
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func (s *Server) ReadDHCPRequest() (*dhcp.BootRequest, error) {
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pkt, addr, err := s.ReadFrom()
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if err != nil {
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return nil, err
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}
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log.Debugf("server: read packet from %s", addr)
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return dhcp.ReadRequest(pkt)
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}
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func (s *Server) WriteTo(b []byte, addr net.Addr) error {
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return errors.New("server: not implemented")
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}
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func (s *Server) AcceptPacket() error {
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request, err := s.ReadDHCPRequest()
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if err != nil {
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return err
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}
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log.Debugf("BOOTP request received from %x", request.HardwareAddress)
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return nil
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}
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func (s *Server) Listen() {
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for {
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if err := s.AcceptPacket(); err != nil {
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log.Errf("server: error reading packet: %s", err)
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continue
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}
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break
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}
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}
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func New(cfg *config.Config) (*Server, error) {
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srv := &Server{
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Config: cfg,
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Pools: map[string]*iptools.Pool{},
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Static: map[string]*iptools.LeaseInfo{},
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}
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if err := srv.loadPoolsFromConfig(); err != nil {
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return nil, err
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}
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if err := srv.LoadLeases(); err != nil {
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return nil, err
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}
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if err := srv.Bind(); err != nil {
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return nil, err
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}
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log.Infof("server: bound to %s:%s", cfg.Interface, srv.Conn.LocalAddr())
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return srv, nil
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}
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func (srv *Server) SelectLease(req *dhcp.BootRequest, t time.Time) *iptools.LeaseInfo {
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if li, ok := srv.Static[req.HostName]; ok {
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return li
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}
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if pool, ok := srv.Pools[req.HostName]; ok {
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return pool.Peek(t, MaxResponseWait)
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}
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if pool, ok := srv.Pools[DefaultPool]; ok {
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return pool.Peek(t, MaxResponseWait)
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}
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return nil
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}
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