tools.go_stun

Yohn Y. 2020-04-05 Child:4b125c1ef311

0:bfbb685d7758 Go to Latest

tools.go_stun/main.go

.. init

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1 package main
2
3 import (
4 "errors"
5 "fmt"
6 "log/syslog"
7 "net"
8 "os"
9 "strings"
10 "time"
11 )
12
13 const (
14 LOG_IDENT string = "net.a0fs.gostun"
15 )
16
17 func getPort() (res string, err error) {
18 if len(os.Args) < 2 {
19 err = errors.New("No port specify")
20 } else {
21 res = fmt.Sprintf(":%s", os.Args[1])
22 }
23 return
24 }
25
26 func fail(code int, msg string) {
27 usage := "Usage: cmd port"
28 usage += "\n port: port number for listening clients"
29
30 fmt.Fprintln(os.Stderr, msg)
31 fmt.Fprintln(os.Stderr, usage)
32 os.Exit(code)
33 return
34 }
35
36 func handler(conn net.Conn) {
37 log, err := syslog.New(syslog.LOG_USER, LOG_IDENT)
38 if err != nil {
39 panic(err)
40 }
41
42 _s_tm := time.Now()
43 remoteAddr := conn.RemoteAddr().String()
44
45 defer func() {
46 var err error
47 _s_tmd := time.Now().Sub(_s_tm)
48 if r_err := recover(); r_err != nil {
49 err = log.Err(fmt.Sprintf("Error on service for %s (service time: %v): %v", remoteAddr, _s_tmd, r_err))
50 if err != nil {
51 panic(err)
52 }
53 } else {
54 err = conn.Close()
55 if err != nil {
56 err = log.Err(fmt.Sprintf("Error on closing socket when service %s (service time: %v): %v",
57 remoteAddr, _s_tmd, err))
58
59 if err != nil {
60 panic(err)
61 }
62 } else {
63 err = log.Info(fmt.Sprintf("Ok service %s in %v", remoteAddr, _s_tmd))
64 if err != nil {
65 panic(err)
66 }
67 }
68 }
69
70 }()
71
72 addr_spit := strings.Split(remoteAddr, ":")
73 addr_last := len(addr_spit) - 1
74 addr := "IP: " + strings.Join(addr_spit[:addr_last], ":") + "\n"
75 port := "Port: " + addr_spit[addr_last] + "\n"
76
77 if _, err := conn.Write([]byte(addr)); err != nil {
78 panic(err)
79 }
80 if _, err := conn.Write([]byte(port)); err != nil {
81 panic(err)
82 }
83 }
84
85 func main() {
86 port, err := getPort()
87 if err != nil {
88 fail(1, fmt.Sprint("Error in parsing port number: ", err))
89 }
90
91 svc, err := net.Listen("tcp", port)
92 if err != nil {
93 fail(2, fmt.Sprint("Fail to open socket: ", err))
94 }
95
96 for {
97 conn, err := svc.Accept()
98 if err != nil {
99 fail(1, fmt.Sprint("Error accepting connections: ", err))
100 }
101 go handler(conn)
102 }
103 }