SSL_accept.3ossl 4.3 KB

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  57. .IX Title "SSL_ACCEPT 3ossl"
  58. .TH SSL_ACCEPT 3ossl 2025-01-17 3.4.0 OpenSSL
  59. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
  60. .\" way too many mistakes in technical documents.
  61. .if n .ad l
  62. .nh
  63. .SH NAME
  64. SSL_accept \- wait for a TLS/SSL client to initiate a TLS/SSL handshake
  65. .SH SYNOPSIS
  66. .IX Header "SYNOPSIS"
  67. .Vb 1
  68. \& #include <openssl/ssl.h>
  69. \&
  70. \& int SSL_accept(SSL *ssl);
  71. .Ve
  72. .SH DESCRIPTION
  73. .IX Header "DESCRIPTION"
  74. \&\fBSSL_accept()\fR waits for a TLS/SSL client to initiate the TLS/SSL handshake.
  75. The communication channel must already have been set and assigned to the
  76. \&\fBssl\fR by setting an underlying \fBBIO\fR.
  77. .SH NOTES
  78. .IX Header "NOTES"
  79. The behaviour of \fBSSL_accept()\fR depends on the underlying BIO.
  80. .PP
  81. If the underlying BIO is \fBblocking\fR, \fBSSL_accept()\fR will only return once the
  82. handshake has been finished or an error occurred.
  83. .PP
  84. If the underlying BIO is \fBnonblocking\fR, \fBSSL_accept()\fR will also return
  85. when the underlying BIO could not satisfy the needs of \fBSSL_accept()\fR
  86. to continue the handshake, indicating the problem by the return value \-1.
  87. In this case a call to \fBSSL_get_error()\fR with the
  88. return value of \fBSSL_accept()\fR will yield \fBSSL_ERROR_WANT_READ\fR or
  89. \&\fBSSL_ERROR_WANT_WRITE\fR. The calling process then must repeat the call after
  90. taking appropriate action to satisfy the needs of \fBSSL_accept()\fR.
  91. The action depends on the underlying BIO. When using a nonblocking socket,
  92. nothing is to be done, but \fBselect()\fR can be used to check for the required
  93. condition. When using a buffering BIO, like a BIO pair, data must be written
  94. into or retrieved out of the BIO before being able to continue.
  95. .SH "RETURN VALUES"
  96. .IX Header "RETURN VALUES"
  97. The following return values can occur:
  98. .IP 0 4
  99. The TLS/SSL handshake was not successful but was shut down controlled and
  100. by the specifications of the TLS/SSL protocol. Call \fBSSL_get_error()\fR with the
  101. return value \fBret\fR to find out the reason.
  102. .IP 1 4
  103. .IX Item "1"
  104. The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
  105. established.
  106. .IP <0 4
  107. .IX Item "<0"
  108. The TLS/SSL handshake was not successful because a fatal error occurred either
  109. at the protocol level or a connection failure occurred. The shutdown was
  110. not clean. It can also occur if action is needed to continue the operation
  111. for nonblocking BIOs. Call \fBSSL_get_error()\fR with the return value \fBret\fR
  112. to find out the reason.
  113. .SH "SEE ALSO"
  114. .IX Header "SEE ALSO"
  115. \&\fBSSL_get_error\fR\|(3), \fBSSL_connect\fR\|(3),
  116. \&\fBSSL_shutdown\fR\|(3), \fBssl\fR\|(7), \fBbio\fR\|(7),
  117. \&\fBSSL_set_connect_state\fR\|(3),
  118. \&\fBSSL_do_handshake\fR\|(3),
  119. \&\fBSSL_CTX_new\fR\|(3)
  120. .SH COPYRIGHT
  121. .IX Header "COPYRIGHT"
  122. Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved.
  123. .PP
  124. Licensed under the Apache License 2.0 (the "License"). You may not use
  125. this file except in compliance with the License. You can obtain a copy
  126. in the file LICENSE in the source distribution or at
  127. <https://www.openssl.org/source/license.html>.