conn.go 3.8 KB

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  1. package tcpprox
  2. import (
  3. "io"
  4. "log"
  5. "net"
  6. "sync"
  7. "time"
  8. )
  9. func isValidIP(ip string) bool {
  10. parsedIP := net.ParseIP(ip)
  11. return parsedIP != nil
  12. }
  13. /*
  14. Connection Copy
  15. Copy between two connections, and accumlate the copied bytes in the
  16. accumulator number
  17. */
  18. func connCopy(conn1 net.Conn, conn2 net.Conn, wg *sync.WaitGroup, accumulator *int64) {
  19. io.Copy(conn1, conn2)
  20. conn1.Close()
  21. log.Println("[←]", "close the connect at local:["+conn1.LocalAddr().String()+"] and remote:["+conn1.RemoteAddr().String()+"]")
  22. //conn2.Close()
  23. //log.Println("[←]", "close the connect at local:["+conn2.LocalAddr().String()+"] and remote:["+conn2.RemoteAddr().String()+"]")
  24. wg.Done()
  25. }
  26. func forward(conn1 net.Conn, conn2 net.Conn) {
  27. log.Printf("[+] start transmit. [%s],[%s] <-> [%s],[%s] \n", conn1.LocalAddr().String(), conn1.RemoteAddr().String(), conn2.LocalAddr().String(), conn2.RemoteAddr().String())
  28. var wg sync.WaitGroup
  29. // wait tow goroutines
  30. wg.Add(2)
  31. go connCopy(conn1, conn2, &wg)
  32. go connCopy(conn2, conn1, &wg)
  33. //blocking when the wg is locked
  34. wg.Wait()
  35. }
  36. func accept(listener net.Listener) net.Conn {
  37. conn, err := listener.Accept()
  38. if err != nil {
  39. log.Println("[x]", "accept connect ["+conn.RemoteAddr().String()+"] faild.", err.Error())
  40. return nil
  41. }
  42. log.Println("[√]", "accept a new client. remote address:["+conn.RemoteAddr().String()+"], local address:["+conn.LocalAddr().String()+"]")
  43. return conn
  44. }
  45. func start_server(address string) net.Listener {
  46. log.Println("[+]", "try to start server on:["+address+"]")
  47. server, err := net.Listen("tcp", address)
  48. if err != nil {
  49. log.Fatalln("[x]", "listen address ["+address+"] faild.")
  50. }
  51. log.Println("[√]", "start listen at address:["+address+"]")
  52. return server
  53. }
  54. func port2port(port1 string, port2 string) {
  55. listen1 := start_server("0.0.0.0:" + port1)
  56. listen2 := start_server("0.0.0.0:" + port2)
  57. log.Println("[√]", "listen port:", port1, "and", port2, "success. waiting for client...")
  58. for {
  59. conn1 := accept(listen1)
  60. conn2 := accept(listen2)
  61. if conn1 == nil || conn2 == nil {
  62. log.Println("[x]", "accept client faild. retry in ", timeout, " seconds. ")
  63. time.Sleep(timeout * time.Second)
  64. continue
  65. }
  66. forward(conn1, conn2)
  67. }
  68. }
  69. func port2host(allowPort string, targetAddress string) {
  70. server := start_server("0.0.0.0:" + allowPort)
  71. for {
  72. conn := accept(server)
  73. if conn == nil {
  74. continue
  75. }
  76. //println(targetAddress)
  77. go func(targetAddress string) {
  78. log.Println("[+]", "start connect host:["+targetAddress+"]")
  79. target, err := net.Dial("tcp", targetAddress)
  80. if err != nil {
  81. // temporarily unavailable, don't use fatal.
  82. log.Println("[x]", "connect target address ["+targetAddress+"] faild. retry in ", timeout, "seconds. ")
  83. conn.Close()
  84. log.Println("[←]", "close the connect at local:["+conn.LocalAddr().String()+"] and remote:["+conn.RemoteAddr().String()+"]")
  85. time.Sleep(timeout * time.Second)
  86. return
  87. }
  88. log.Println("[→]", "connect target address ["+targetAddress+"] success.")
  89. forward(target, conn)
  90. }(targetAddress)
  91. }
  92. }
  93. func host2host(address1, address2 string) {
  94. for {
  95. log.Println("[+]", "try to connect host:["+address1+"] and ["+address2+"]")
  96. var host1, host2 net.Conn
  97. var err error
  98. for {
  99. host1, err = net.Dial("tcp", address1)
  100. if err == nil {
  101. log.Println("[→]", "connect ["+address1+"] success.")
  102. break
  103. } else {
  104. log.Println("[x]", "connect target address ["+address1+"] faild. retry in ", timeout, " seconds. ")
  105. time.Sleep(timeout * time.Second)
  106. }
  107. }
  108. for {
  109. host2, err = net.Dial("tcp", address2)
  110. if err == nil {
  111. log.Println("[→]", "connect ["+address2+"] success.")
  112. break
  113. } else {
  114. log.Println("[x]", "connect target address ["+address2+"] faild. retry in ", timeout, " seconds. ")
  115. time.Sleep(timeout * time.Second)
  116. }
  117. }
  118. forward(host1, host2)
  119. }
  120. }