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* Added DHCPv4 server * Added more modifiers * Fixed some bugs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,154 @@ | ||
| package dhcpv4 | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "log" | ||
| "net" | ||
| "sync" | ||
| "time" | ||
| ) | ||
|
|
||
| /* | ||
| To use the DHCPv4 server code you have to call NewServer with two arguments: | ||
| - a handler function, that will be called every time a valid DHCPv4 packet is | ||
| received, and | ||
| - an address to listen on. | ||
| 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. | ||
| 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. | ||
| Example program: | ||
| package main | ||
| import ( | ||
| "log" | ||
| "net" | ||
| "github.com/insomniacslk/dhcp/dhcpv4" | ||
| ) | ||
| 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 := dhcpv4.NewServer(laddr, handler) | ||
| defer server.Close() | ||
| if err := server.ActivateAndServe(); err != nil { | ||
| log.Panic(err) | ||
| } | ||
| } | ||
| */ | ||
|
|
||
| // Handler is a type that defines the handler function to be called every time a | ||
| // valid DHCPv4 message is received | ||
| type Handler func(conn net.PacketConn, peer net.Addr, m *DHCPv4) | ||
|
|
||
| // Server represents a DHCPv4 server object | ||
| type Server struct { | ||
| conn net.PacketConn | ||
| connMutex sync.Mutex | ||
| shouldStop chan bool | ||
| Handler Handler | ||
| localAddr net.UDPAddr | ||
| } | ||
|
|
||
| // LocalAddr returns the local address of the listening socket, or nil if not | ||
| // listening | ||
| func (s *Server) LocalAddr() net.Addr { | ||
| s.connMutex.Lock() | ||
| defer s.connMutex.Unlock() | ||
| if s.conn == nil { | ||
| return nil | ||
| } | ||
| return s.conn.LocalAddr() | ||
| } | ||
|
|
||
| // ActivateAndServe starts the DHCPv4 server | ||
| func (s *Server) ActivateAndServe() error { | ||
| s.connMutex.Lock() | ||
| if s.conn == nil { | ||
| conn, err := net.ListenUDP("udp4", &s.localAddr) | ||
| if err != nil { | ||
| s.connMutex.Unlock() | ||
| return err | ||
| } | ||
| s.conn = conn | ||
| } | ||
| s.connMutex.Unlock() | ||
| defer s.Close() | ||
| var ( | ||
| pc *net.UDPConn | ||
| ok bool | ||
| ) | ||
| if pc, ok = s.conn.(*net.UDPConn); !ok { | ||
| return fmt.Errorf("Error: not an UDPConn") | ||
| } | ||
| if pc == nil { | ||
| return fmt.Errorf("ActivateAndServe: Invalid nil PacketConn") | ||
| } | ||
| log.Printf("Server listening on %s", pc.LocalAddr()) | ||
| log.Print("Ready to handle requests") | ||
| for { | ||
| select { | ||
| case <-s.shouldStop: | ||
| break | ||
| case <-time.After(time.Millisecond): | ||
| } | ||
| pc.SetReadDeadline(time.Now().Add(time.Second)) | ||
| rbuf := make([]byte, 4096) // FIXME this is bad | ||
| n, peer, err := pc.ReadFrom(rbuf) | ||
| if err != nil { | ||
| switch err.(type) { | ||
| case net.Error: | ||
| // silently skip and continue | ||
| default: | ||
| // complain and continue | ||
| log.Printf("Error reading from packet conn: %v", err) | ||
| } | ||
| continue | ||
| } | ||
| log.Printf("Handling request from %v", peer) | ||
| m, err := FromBytes(rbuf[:n]) | ||
| if err != nil { | ||
| log.Printf("Error parsing DHCPv4 request: %v", err) | ||
| continue | ||
| } | ||
| s.Handler(pc, peer, m) | ||
| } | ||
| return nil | ||
| } | ||
|
|
||
| // Close sends a termination request to the server, and closes the UDP listener | ||
| func (s *Server) Close() error { | ||
| s.shouldStop <- true | ||
| s.connMutex.Lock() | ||
| defer s.connMutex.Unlock() | ||
| if s.conn != nil { | ||
| return s.conn.Close() | ||
| } | ||
| return nil | ||
| } | ||
|
|
||
| // NewServer initializes and returns a new Server object | ||
| func NewServer(addr net.UDPAddr, handler Handler) *Server { | ||
| return &Server{ | ||
| localAddr: addr, | ||
| Handler: handler, | ||
| shouldStop: make(chan bool, 1), | ||
| } | ||
| } |
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