1 925168e0 2022-04-14 o package mailmux
 2 925168e0 2022-04-14 o 
 3 925168e0 2022-04-14 o import (
 4 925168e0 2022-04-14 o 	"errors"
 5 925168e0 2022-04-14 o 	"fmt"
 6 71bdede3 2022-04-21 o 	"io"
 7 71bdede3 2022-04-21 o 	"net"
 8 71bdede3 2022-04-21 o 	"os"
 9 925168e0 2022-04-14 o )
10 925168e0 2022-04-14 o 
11 925168e0 2022-04-14 o type Server struct {
12 71bdede3 2022-04-21 o 	ln      net.Listener
13 71bdede3 2022-04-21 o 	Aliases AliasStore
14 71bdede3 2022-04-21 o 	Users   UserStore
15 925168e0 2022-04-14 o }
16 925168e0 2022-04-14 o 
17 71bdede3 2022-04-21 o func (srv *Server) ListenAndServe() error {
18 71bdede3 2022-04-21 o 	if srv.ln == nil {
19 71bdede3 2022-04-21 o 		return errors.New("nil listener")
20 925168e0 2022-04-14 o 	}
21 71bdede3 2022-04-21 o 	return srv.Serve(srv.ln)
22 925168e0 2022-04-14 o }
23 925168e0 2022-04-14 o 
24 71bdede3 2022-04-21 o func (srv *Server) Serve(ln net.Listener) error {
25 71bdede3 2022-04-21 o 	if ln == nil {
26 71bdede3 2022-04-21 o 		return errors.New("nil listener")
27 925168e0 2022-04-14 o 	}
28 71bdede3 2022-04-21 o 	for {
29 71bdede3 2022-04-21 o 		conn, err := ln.Accept()
30 71bdede3 2022-04-21 o 		if err != nil {
31 71bdede3 2022-04-21 o 			return err
32 71bdede3 2022-04-21 o 		}
33 71bdede3 2022-04-21 o 		go func() {
34 71bdede3 2022-04-21 o 			if err := srv.handleConn(conn); err != nil {
35 71bdede3 2022-04-21 o 				fmt.Fprintln(os.Stderr, err)
36 71bdede3 2022-04-21 o 			}
37 71bdede3 2022-04-21 o 			conn.Close()
38 71bdede3 2022-04-21 o 		}()
39 925168e0 2022-04-14 o 	}
40 71bdede3 2022-04-21 o 	return errors.New("unreachable?")
41 925168e0 2022-04-14 o }
42 925168e0 2022-04-14 o 
43 71bdede3 2022-04-21 o func (srv *Server) handleConn(conn net.Conn) error {
44 71bdede3 2022-04-21 o 	tmsg, err := ParseMcall(conn)
45 925168e0 2022-04-14 o 	if err != nil {
46 71bdede3 2022-04-21 o 		err = fmt.Errorf("parse mcall: %w", err)
47 71bdede3 2022-04-21 o 		rerror(conn, err.Error())
48 71bdede3 2022-04-21 o 		return err
49 925168e0 2022-04-14 o 	}
50 71bdede3 2022-04-21 o 	if tmsg.Type != Tauth {
51 71bdede3 2022-04-21 o 		rerror(conn, "unauthorised")
52 71bdede3 2022-04-21 o 		return nil
53 925168e0 2022-04-14 o 	}
54 71bdede3 2022-04-21 o 	if err := srv.Users.Authenticate(tmsg.Username, Password(tmsg.Password)); err != nil {
55 71bdede3 2022-04-21 o 		rerror(conn, "authentication failed")
56 71bdede3 2022-04-21 o 		return err
57 71bdede3 2022-04-21 o 	}
58 71bdede3 2022-04-21 o 	rmsg := &Mcall{Type: Rauth, Username: tmsg.Username}
59 71bdede3 2022-04-21 o 	writeMcall(conn, rmsg)
60 925168e0 2022-04-14 o 
61 71bdede3 2022-04-21 o 	user := tmsg.Username
62 71bdede3 2022-04-21 o 	for {
63 71bdede3 2022-04-21 o 		tmsg, err := ParseMcall(conn)
64 71bdede3 2022-04-21 o 		if errors.Is(err, io.EOF) {
65 71bdede3 2022-04-21 o 			return nil
66 71bdede3 2022-04-21 o 		} else if err != nil {
67 71bdede3 2022-04-21 o 			rerror(conn, err.Error())
68 71bdede3 2022-04-21 o 			continue
69 71bdede3 2022-04-21 o 		}
70 71bdede3 2022-04-21 o 		rmsg := &Mcall{}
71 71bdede3 2022-04-21 o 		switch tmsg.Type {
72 71bdede3 2022-04-21 o 		case Tauth:
73 71bdede3 2022-04-21 o 			rmsg = &Mcall{Type: Rerror, Error: "already authenticated"}
74 71bdede3 2022-04-21 o 		case Tlist:
75 71bdede3 2022-04-21 o 			rmsg = srv.listAliases(user)
76 71bdede3 2022-04-21 o 		case Tcreate:
77 71bdede3 2022-04-21 o 			rmsg = srv.createAlias(user)
78 71bdede3 2022-04-21 o 		default:
79 71bdede3 2022-04-21 o 			rmsg = &Mcall{Type: Rerror, Error: "this tmessage not implemented yet"}
80 71bdede3 2022-04-21 o 		}
81 71bdede3 2022-04-21 o 		writeMcall(conn, rmsg)
82 925168e0 2022-04-14 o 	}
83 925168e0 2022-04-14 o }
84 925168e0 2022-04-14 o 
85 71bdede3 2022-04-21 o func (srv *Server) createAlias(username string) *Mcall {
86 71bdede3 2022-04-21 o 	alias, err := srv.Aliases.Create(username)
87 925168e0 2022-04-14 o 	if err != nil {
88 925168e0 2022-04-14 o 		return &Mcall{Type: Rerror, Error: err.Error()}
89 925168e0 2022-04-14 o 	}
90 71bdede3 2022-04-21 o 	return &Mcall{Type: Rcreate, Aliases: []Alias{alias}}
91 925168e0 2022-04-14 o }
92 925168e0 2022-04-14 o 
93 71bdede3 2022-04-21 o func (srv *Server) listAliases(username string) *Mcall {
94 71bdede3 2022-04-21 o 	a, err := srv.Aliases.Aliases(username)
95 925168e0 2022-04-14 o 	if err != nil {
96 71bdede3 2022-04-21 o 		return &Mcall{Type: Rerror, Error: fmt.Sprintf("aliases for %s: %v", username, err)}
97 925168e0 2022-04-14 o 	}
98 71bdede3 2022-04-21 o 	return &Mcall{Type: Rlist, Aliases: a}
99 925168e0 2022-04-14 o }