SSL_accept.3ossl 6.8 KB

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  133. .\" ========================================================================
  134. .\"
  135. .IX Title "SSL_ACCEPT 3ossl"
  136. .TH SSL_ACCEPT 3ossl "2024-09-03" "3.3.2" "OpenSSL"
  137. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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  139. .if n .ad l
  140. .nh
  141. .SH "NAME"
  142. SSL_accept \- wait for a TLS/SSL client to initiate a TLS/SSL handshake
  143. .SH "SYNOPSIS"
  144. .IX Header "SYNOPSIS"
  145. .Vb 1
  146. \& #include <openssl/ssl.h>
  147. \&
  148. \& int SSL_accept(SSL *ssl);
  149. .Ve
  150. .SH "DESCRIPTION"
  151. .IX Header "DESCRIPTION"
  152. \&\fBSSL_accept()\fR waits for a \s-1TLS/SSL\s0 client to initiate the \s-1TLS/SSL\s0 handshake.
  153. The communication channel must already have been set and assigned to the
  154. \&\fBssl\fR by setting an underlying \fB\s-1BIO\s0\fR.
  155. .SH "NOTES"
  156. .IX Header "NOTES"
  157. The behaviour of \fBSSL_accept()\fR depends on the underlying \s-1BIO.\s0
  158. .PP
  159. If the underlying \s-1BIO\s0 is \fBblocking\fR, \fBSSL_accept()\fR will only return once the
  160. handshake has been finished or an error occurred.
  161. .PP
  162. If the underlying \s-1BIO\s0 is \fBnonblocking\fR, \fBSSL_accept()\fR will also return
  163. when the underlying \s-1BIO\s0 could not satisfy the needs of \fBSSL_accept()\fR
  164. to continue the handshake, indicating the problem by the return value \-1.
  165. In this case a call to \fBSSL_get_error()\fR with the
  166. return value of \fBSSL_accept()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or
  167. \&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. The calling process then must repeat the call after
  168. taking appropriate action to satisfy the needs of \fBSSL_accept()\fR.
  169. The action depends on the underlying \s-1BIO.\s0 When using a nonblocking socket,
  170. nothing is to be done, but \fBselect()\fR can be used to check for the required
  171. condition. When using a buffering \s-1BIO,\s0 like a \s-1BIO\s0 pair, data must be written
  172. into or retrieved out of the \s-1BIO\s0 before being able to continue.
  173. .SH "RETURN VALUES"
  174. .IX Header "RETURN VALUES"
  175. The following return values can occur:
  176. .IP "0" 4
  177. The \s-1TLS/SSL\s0 handshake was not successful but was shut down controlled and
  178. by the specifications of the \s-1TLS/SSL\s0 protocol. Call \fBSSL_get_error()\fR with the
  179. return value \fBret\fR to find out the reason.
  180. .IP "1" 4
  181. .IX Item "1"
  182. The \s-1TLS/SSL\s0 handshake was successfully completed, a \s-1TLS/SSL\s0 connection has been
  183. established.
  184. .IP "<0" 4
  185. .IX Item "<0"
  186. The \s-1TLS/SSL\s0 handshake was not successful because a fatal error occurred either
  187. at the protocol level or a connection failure occurred. The shutdown was
  188. not clean. It can also occur if action is needed to continue the operation
  189. for nonblocking BIOs. Call \fBSSL_get_error()\fR with the return value \fBret\fR
  190. to find out the reason.
  191. .SH "SEE ALSO"
  192. .IX Header "SEE ALSO"
  193. \&\fBSSL_get_error\fR\|(3), \fBSSL_connect\fR\|(3),
  194. \&\fBSSL_shutdown\fR\|(3), \fBssl\fR\|(7), \fBbio\fR\|(7),
  195. \&\fBSSL_set_connect_state\fR\|(3),
  196. \&\fBSSL_do_handshake\fR\|(3),
  197. \&\fBSSL_CTX_new\fR\|(3)
  198. .SH "COPYRIGHT"
  199. .IX Header "COPYRIGHT"
  200. Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved.
  201. .PP
  202. Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use
  203. this file except in compliance with the License. You can obtain a copy
  204. in the file \s-1LICENSE\s0 in the source distribution or at
  205. <https://www.openssl.org/source/license.html>.