Documentation
¶
Overview ¶
Package server4 is a basic, extensible DHCPv4 server.
To use the DHCPv4 server code you have to call NewServer with two arguments:
- an interface to listen on,
- an address to listen on, and
- a handler function, that will be called every time a valid DHCPv4 packet is received.
The address to listen on is used to know IP address, port and optionally the scope to create and UDP socket to listen on for DHCPv4 traffic.
The handler is a function that takes as input a packet connection, that can be used to reply to the client; a peer address, that identifies the client sending the request, and the DHCPv4 packet itself. Just implement your custom logic in the handler.
Optionally, NewServer can receive options that will modify the server object. Some options already exist, for example WithConn. If this option is passed with a valid connection, the listening address argument is ignored.
Example program:
package main
import (
"log"
"net"
"github.com/csystem-it/dhcp/dhcpv4"
"github.com/csystem-it/dhcp/dhcpv4/server4"
)
func handler(conn net.PacketConn, peer net.Addr, m *dhcpv4.DHCPv4) {
// this function will just print the received DHCPv4 message, without replying
log.Print(m.Summary())
}
func main() {
laddr := net.UDPAddr{
IP: net.ParseIP("127.0.0.1"),
Port: 67,
}
server, err := server4.NewServer("eth0", &laddr, handler)
if err != nil {
log.Fatal(err)
}
// This never returns. If you want to do other stuff, dump it into a
// goroutine.
server.Serve()
}
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type DebugLogger ¶
type DebugLogger struct {
// Printfer is used for actual output of the logger
Printfer
}
DebugLogger is a wrapper for Printfer to implement interface Logger. DHCP messages are printed in the long format.
func (DebugLogger) PrintMessage ¶
func (d DebugLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4)
PrintMessage prints a DHCP message in the long format via predefined Printfer
func (DebugLogger) Printf ¶
func (d DebugLogger) Printf(format string, v ...interface{})
Printf prints a log message as-is via predefined Printfer
type EmptyLogger ¶
type EmptyLogger struct{}
EmptyLogger prints nothing
func (EmptyLogger) PrintMessage ¶
func (e EmptyLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4)
PrintMessage is just a dummy function that does nothing
func (EmptyLogger) Printf ¶
func (e EmptyLogger) Printf(format string, v ...interface{})
Printf is just a dummy function that does nothing
type Handler ¶
Handler is a type that defines the handler function to be called every time a valid DHCPv4 message is received
type Logger ¶
type Logger interface {
// PrintMessage print _all_ DHCP messages
PrintMessage(prefix string, message *dhcpv4.DHCPv4)
// Printf is use to print the rest debugging information
Printf(format string, v ...interface{})
}
Logger is a handler which will be used to output logging messages
type Printfer ¶
type Printfer interface {
// Printf is the function for logging output. Arguments are handled in the manner of fmt.Printf.
Printf(format string, v ...interface{})
}
Printfer is used for actual output of the logger. For example *log.Logger is a Printfer.
type Server ¶
type Server struct {
Handler Handler
// contains filtered or unexported fields
}
Server represents a DHCPv4 server object
func NewServer ¶
func NewServer(ifname string, addr *net.UDPAddr, handler Handler, opt ...ServerOpt) (*Server, error)
NewServer initializes and returns a new Server object
type ServerOpt ¶
type ServerOpt func(s *Server)
ServerOpt adds optional configuration to a server.
func WithConn ¶
func WithConn(c net.PacketConn) ServerOpt
WithConn configures the server with the given connection.
func WithDebugLogger ¶
func WithDebugLogger() ServerOpt
WithDebugLogger logs multi-line full DHCPv4 messages when sent & received.
func WithLogger ¶
WithLogger set the logger (see interface Logger).
func WithSummaryLogger ¶
func WithSummaryLogger() ServerOpt
WithSummaryLogger logs one-line DHCPv4 message summaries when sent & received.
type ShortSummaryLogger ¶
type ShortSummaryLogger struct {
// Printfer is used for actual output of the logger
Printfer
}
ShortSummaryLogger is a wrapper for Printfer to implement interface Logger. DHCP messages are printed in the short format.
func (ShortSummaryLogger) PrintMessage ¶
func (s ShortSummaryLogger) PrintMessage(prefix string, message *dhcpv4.DHCPv4)
PrintMessage prints a DHCP message in the short format via predefined Printfer
func (ShortSummaryLogger) Printf ¶
func (s ShortSummaryLogger) Printf(format string, v ...interface{})
Printf prints a log message as-is via predefined Printfer
Source Files