SSL_CTX_set_timeout.3ossl 4.2 KB

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  57. .IX Title "SSL_CTX_SET_TIMEOUT 3ossl"
  58. .TH SSL_CTX_SET_TIMEOUT 3ossl 2025-01-17 3.4.0 OpenSSL
  59. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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  61. .if n .ad l
  62. .nh
  63. .SH NAME
  64. SSL_CTX_set_timeout, SSL_CTX_get_timeout \- manipulate timeout values for session caching
  65. .SH SYNOPSIS
  66. .IX Header "SYNOPSIS"
  67. .Vb 1
  68. \& #include <openssl/ssl.h>
  69. \&
  70. \& long SSL_CTX_set_timeout(SSL_CTX *ctx, long t);
  71. \& long SSL_CTX_get_timeout(SSL_CTX *ctx);
  72. .Ve
  73. .SH DESCRIPTION
  74. .IX Header "DESCRIPTION"
  75. \&\fBSSL_CTX_set_timeout()\fR sets the timeout for newly created sessions for
  76. \&\fBctx\fR to \fBt\fR. The timeout value \fBt\fR must be given in seconds.
  77. .PP
  78. \&\fBSSL_CTX_get_timeout()\fR returns the currently set timeout value for \fBctx\fR.
  79. .SH NOTES
  80. .IX Header "NOTES"
  81. Whenever a new session is created, it is assigned a maximum lifetime. This
  82. lifetime is specified by storing the creation time of the session and the
  83. timeout value valid at this time. If the actual time is later than creation
  84. time plus timeout, the session is not reused.
  85. .PP
  86. Due to this realization, all sessions behave according to the timeout value
  87. valid at the time of the session negotiation. Changes of the timeout value
  88. do not affect already established sessions.
  89. .PP
  90. The expiration time of a single session can be modified using the
  91. \&\fBSSL_SESSION_get_time\fR\|(3) family of functions.
  92. .PP
  93. Expired sessions are removed from the internal session cache, whenever
  94. \&\fBSSL_CTX_flush_sessions\fR\|(3) is called, either
  95. directly by the application or automatically (see
  96. \&\fBSSL_CTX_set_session_cache_mode\fR\|(3))
  97. .PP
  98. The default value for session timeout is decided on a per protocol
  99. basis, see \fBSSL_get_default_timeout\fR\|(3).
  100. All currently supported protocols have the same default timeout value
  101. of 300 seconds.
  102. .PP
  103. This timeout value is used as the ticket lifetime hint for stateless session
  104. tickets. It is also used as the timeout value within the ticket itself.
  105. .PP
  106. For TLSv1.3, RFC8446 limits transmission of this value to 1 week (604800
  107. seconds).
  108. .PP
  109. For TLSv1.2, tickets generated during an initial handshake use the value
  110. as specified. Tickets generated during a resumed handshake have a value
  111. of 0 for the ticket lifetime hint.
  112. .SH "RETURN VALUES"
  113. .IX Header "RETURN VALUES"
  114. \&\fBSSL_CTX_set_timeout()\fR returns the previously set timeout value.
  115. .PP
  116. \&\fBSSL_CTX_get_timeout()\fR returns the currently set timeout value.
  117. .SH "SEE ALSO"
  118. .IX Header "SEE ALSO"
  119. \&\fBssl\fR\|(7),
  120. \&\fBSSL_CTX_set_session_cache_mode\fR\|(3),
  121. \&\fBSSL_SESSION_get_time\fR\|(3),
  122. \&\fBSSL_CTX_flush_sessions\fR\|(3),
  123. \&\fBSSL_get_default_timeout\fR\|(3)
  124. .SH COPYRIGHT
  125. .IX Header "COPYRIGHT"
  126. Copyright 2001\-2022 The OpenSSL Project Authors. All Rights Reserved.
  127. .PP
  128. Licensed under the Apache License 2.0 (the "License"). You may not use
  129. this file except in compliance with the License. You can obtain a copy
  130. in the file LICENSE in the source distribution or at
  131. <https://www.openssl.org/source/license.html>.