BIO_s_connect.pod 7.3 KB

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  1. =pod
  2. =head1 NAME
  3. BIO_set_conn_address, BIO_get_conn_address,
  4. BIO_s_connect, BIO_new_connect, BIO_set_conn_hostname, BIO_set_conn_port,
  5. BIO_set_conn_ip_family, BIO_get_conn_ip_family,
  6. BIO_get_conn_hostname, BIO_get_conn_port,
  7. BIO_set_nbio, BIO_do_connect - connect BIO
  8. =head1 SYNOPSIS
  9. #include <openssl/bio.h>
  10. const BIO_METHOD * BIO_s_connect(void);
  11. BIO *BIO_new_connect(char *name);
  12. long BIO_set_conn_hostname(BIO *b, char *name);
  13. long BIO_set_conn_port(BIO *b, char *port);
  14. long BIO_set_conn_address(BIO *b, BIO_ADDR *addr);
  15. long BIO_set_conn_ip_family(BIO *b, long family);
  16. const char *BIO_get_conn_hostname(BIO *b);
  17. const char *BIO_get_conn_port(BIO *b);
  18. const BIO_ADDR *BIO_get_conn_address(BIO *b);
  19. const long BIO_get_conn_ip_family(BIO *b);
  20. long BIO_set_nbio(BIO *b, long n);
  21. int BIO_do_connect(BIO *b);
  22. =head1 DESCRIPTION
  23. BIO_s_connect() returns the connect BIO method. This is a wrapper
  24. round the platform's TCP/IP socket connection routines.
  25. Using connect BIOs, TCP/IP connections can be made and data
  26. transferred using only BIO routines. In this way any platform
  27. specific operations are hidden by the BIO abstraction.
  28. Read and write operations on a connect BIO will perform I/O
  29. on the underlying connection. If no connection is established
  30. and the port and hostname (see below) is set up properly then
  31. a connection is established first.
  32. Connect BIOs support BIO_puts() but not BIO_gets().
  33. If the close flag is set on a connect BIO then any active
  34. connection is shutdown and the socket closed when the BIO
  35. is freed.
  36. Calling BIO_reset() on a connect BIO will close any active
  37. connection and reset the BIO into a state where it can connect
  38. to the same host again.
  39. BIO_get_fd() places the underlying socket in B<c> if it is not NULL,
  40. it also returns the socket . If B<c> is not NULL it should be of
  41. type (int *).
  42. BIO_set_conn_hostname() uses the string B<name> to set the hostname.
  43. The hostname can be an IP address; if the address is an IPv6 one, it
  44. must be enclosed with brackets. The hostname can also include the
  45. port in the form hostname:port.
  46. BIO_set_conn_port() sets the port to B<port>. B<port> can be the
  47. numerical form or a string such as "http". A string will be looked
  48. up first using getservbyname() on the host platform but if that
  49. fails a standard table of port names will be used. This internal
  50. list is http, telnet, socks, https, ssl, ftp, and gopher.
  51. BIO_set_conn_address() sets the address and port information using
  52. a BIO_ADDR(3ssl).
  53. BIO_set_conn_ip_family() sets the IP family.
  54. BIO_get_conn_hostname() returns the hostname of the connect BIO or
  55. NULL if the BIO is initialized but no hostname is set.
  56. This return value is an internal pointer which should not be modified.
  57. BIO_get_conn_port() returns the port as a string.
  58. This return value is an internal pointer which should not be modified.
  59. BIO_get_conn_address() returns the address information as a BIO_ADDR.
  60. This return value is an internal pointer which should not be modified.
  61. BIO_get_conn_ip_family() returns the IP family of the connect BIO.
  62. BIO_set_nbio() sets the non blocking I/O flag to B<n>. If B<n> is
  63. zero then blocking I/O is set. If B<n> is 1 then non blocking I/O
  64. is set. Blocking I/O is the default. The call to BIO_set_nbio()
  65. should be made before the connection is established because
  66. non blocking I/O is set during the connect process.
  67. BIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into
  68. a single call: that is it creates a new connect BIO with B<name>.
  69. BIO_do_connect() attempts to connect the supplied BIO. It returns 1
  70. if the connection was established successfully. A zero or negative
  71. value is returned if the connection could not be established, the
  72. call BIO_should_retry() should be used for non blocking connect BIOs
  73. to determine if the call should be retried.
  74. =head1 NOTES
  75. If blocking I/O is set then a non positive return value from any
  76. I/O call is caused by an error condition, although a zero return
  77. will normally mean that the connection was closed.
  78. If the port name is supplied as part of the host name then this will
  79. override any value set with BIO_set_conn_port(). This may be undesirable
  80. if the application does not wish to allow connection to arbitrary
  81. ports. This can be avoided by checking for the presence of the ':'
  82. character in the passed hostname and either indicating an error or
  83. truncating the string at that point.
  84. The values returned by BIO_get_conn_hostname(), BIO_get_conn_address(),
  85. and BIO_get_conn_port() are updated when a connection attempt is made.
  86. Before any connection attempt the values returned are those set by the
  87. application itself.
  88. Applications do not have to call BIO_do_connect() but may wish to do
  89. so to separate the connection process from other I/O processing.
  90. If non blocking I/O is set then retries will be requested as appropriate.
  91. It addition to BIO_should_read() and BIO_should_write() it is also
  92. possible for BIO_should_io_special() to be true during the initial
  93. connection process with the reason BIO_RR_CONNECT. If this is returned
  94. then this is an indication that a connection attempt would block,
  95. the application should then take appropriate action to wait until
  96. the underlying socket has connected and retry the call.
  97. BIO_set_conn_hostname(), BIO_set_conn_port(), BIO_get_conn_hostname(),
  98. BIO_set_conn_address(), BIO_get_conn_port(), BIO_get_conn_address(),
  99. BIO_set_conn_ip_family(), BIO_get_conn_ip_family(),
  100. BIO_set_nbio(), and BIO_do_connect() are macros.
  101. =head1 RETURN VALUES
  102. BIO_s_connect() returns the connect BIO method.
  103. BIO_get_fd() returns the socket or -1 if the BIO has not
  104. been initialized.
  105. BIO_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family()
  106. always return 1.
  107. BIO_set_conn_hostname() returns 1 on success and 0 on failure.
  108. BIO_get_conn_address() returns the address information or NULL if none
  109. was set.
  110. BIO_get_conn_hostname() returns the connected hostname or NULL if
  111. none was set.
  112. BIO_get_conn_ip_family() returns the address family or -1 if none was set.
  113. BIO_get_conn_port() returns a string representing the connected
  114. port or NULL if not set.
  115. BIO_set_nbio() always returns 1.
  116. BIO_do_connect() returns 1 if the connection was successfully
  117. established and 0 or -1 if the connection failed.
  118. =head1 EXAMPLE
  119. This is example connects to a webserver on the local host and attempts
  120. to retrieve a page and copy the result to standard output.
  121. BIO *cbio, *out;
  122. int len;
  123. char tmpbuf[1024];
  124. cbio = BIO_new_connect("localhost:http");
  125. out = BIO_new_fp(stdout, BIO_NOCLOSE);
  126. if (BIO_do_connect(cbio) <= 0) {
  127. fprintf(stderr, "Error connecting to server\n");
  128. ERR_print_errors_fp(stderr);
  129. exit(1);
  130. }
  131. BIO_puts(cbio, "GET / HTTP/1.0\n\n");
  132. for (;;) {
  133. len = BIO_read(cbio, tmpbuf, 1024);
  134. if (len <= 0)
  135. break;
  136. BIO_write(out, tmpbuf, len);
  137. }
  138. BIO_free(cbio);
  139. BIO_free(out);
  140. =head1 SEE ALSO
  141. L<BIO_ADDR(3)>
  142. =head1 HISTORY
  143. BIO_set_conn_int_port(), BIO_get_conn_int_port(), BIO_set_conn_ip(), and BIO_get_conn_ip()
  144. were removed in OpenSSL 1.1.0.
  145. Use BIO_set_conn_address() and BIO_get_conn_address() instead.
  146. =head1 COPYRIGHT
  147. Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
  148. Licensed under the OpenSSL license (the "License"). You may not use
  149. this file except in compliance with the License. You can obtain a copy
  150. in the file LICENSE in the source distribution or at
  151. L<https://www.openssl.org/source/license.html>.
  152. =cut