Add identd

pkg/ident/server.go

@@ -0,0 +1,87 @@
+package ident
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"strings"
+	"sync"
+)
+
+var (
+	DefaultAddr = ":113"
+)
+
+type Server struct {
+	Addr string
+
+	idents   map[string]string
+	listener net.Listener
+	lock     sync.Mutex
+}
+
+func NewServer() *Server {
+	return &Server{
+		idents: map[string]string{},
+	}
+}
+
+func (s *Server) Listen() error {
+	var err error
+
+	addr := s.Addr
+	if addr == "" {
+		addr = DefaultAddr
+	}
+
+	s.listener, err = net.Listen("tcp", addr)
+	if err != nil {
+		return err
+	}
+	defer s.listener.Close()
+
+	for {
+		conn, err := s.listener.Accept()
+		if err != nil {
+			return err
+		}
+
+		go s.handle(conn)
+	}
+}
+
+func (s *Server) Stop() error {
+	return s.listener.Close()
+}
+
+func (s *Server) Add(local, remote, ident string) {
+	s.lock.Lock()
+	s.idents[local+","+remote] = ident
+	s.lock.Unlock()
+}
+
+func (s *Server) Remove(local, remote string) {
+	s.lock.Lock()
+	delete(s.idents, local+","+remote)
+	s.lock.Unlock()
+}
+
+func (s *Server) handle(conn net.Conn) {
+	defer conn.Close()
+
+	scan := bufio.NewScanner(conn)
+	if !scan.Scan() {
+		return
+	}
+
+	line := scan.Text()
+	ports := strings.ReplaceAll(line, " ", "")
+
+	s.lock.Lock()
+	ident, ok := s.idents[ports]
+	s.lock.Unlock()
+
+	if ok {
+		conn.Write([]byte(fmt.Sprintf("%s : USERID : Dispatch : %s\r\n", line, ident)))
+	}
+}