SSL_accept.3 6.4 KB

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  131. .IX Title "SSL_accept 3"
  132. .TH SSL_accept 3 "2019-09-12" "1.0.2g" "OpenSSL"
  133. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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  135. .if n .ad l
  136. .nh
  137. .SH "NAME"
  138. SSL_accept \- wait for a TLS/SSL client to initiate a TLS/SSL handshake
  139. .SH "SYNOPSIS"
  140. .IX Header "SYNOPSIS"
  141. .Vb 1
  142. \& #include <openssl/ssl.h>
  143. \&
  144. \& int SSL_accept(SSL *ssl);
  145. .Ve
  146. .SH "DESCRIPTION"
  147. .IX Header "DESCRIPTION"
  148. \&\fISSL_accept()\fR waits for a \s-1TLS/SSL\s0 client to initiate the \s-1TLS/SSL\s0 handshake.
  149. The communication channel must already have been set and assigned to the
  150. \&\fBssl\fR by setting an underlying \fB\s-1BIO\s0\fR.
  151. .SH "NOTES"
  152. .IX Header "NOTES"
  153. The behaviour of \fISSL_accept()\fR depends on the underlying \s-1BIO.\s0
  154. .PP
  155. If the underlying \s-1BIO\s0 is \fBblocking\fR, \fISSL_accept()\fR will only return once the
  156. handshake has been finished or an error occurred.
  157. .PP
  158. If the underlying \s-1BIO\s0 is \fBnon-blocking\fR, \fISSL_accept()\fR will also return
  159. when the underlying \s-1BIO\s0 could not satisfy the needs of \fISSL_accept()\fR
  160. to continue the handshake, indicating the problem by the return value \-1.
  161. In this case a call to \fISSL_get_error()\fR with the
  162. return value of \fISSL_accept()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or
  163. \&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. The calling process then must repeat the call after
  164. taking appropriate action to satisfy the needs of \fISSL_accept()\fR.
  165. The action depends on the underlying \s-1BIO.\s0 When using a non-blocking socket,
  166. nothing is to be done, but \fIselect()\fR can be used to check for the required
  167. condition. When using a buffering \s-1BIO,\s0 like a \s-1BIO\s0 pair, data must be written
  168. into or retrieved out of the \s-1BIO\s0 before being able to continue.
  169. .SH "RETURN VALUES"
  170. .IX Header "RETURN VALUES"
  171. The following return values can occur:
  172. .IP "0" 4
  173. The \s-1TLS/SSL\s0 handshake was not successful but was shut down controlled and
  174. by the specifications of the \s-1TLS/SSL\s0 protocol. Call \fISSL_get_error()\fR with the
  175. return value \fBret\fR to find out the reason.
  176. .IP "1" 4
  177. .IX Item "1"
  178. The \s-1TLS/SSL\s0 handshake was successfully completed, a \s-1TLS/SSL\s0 connection has been
  179. established.
  180. .IP "<0" 4
  181. .IX Item "<0"
  182. The \s-1TLS/SSL\s0 handshake was not successful because a fatal error occurred either
  183. at the protocol level or a connection failure occurred. The shutdown was
  184. not clean. It can also occur of action is need to continue the operation
  185. for non-blocking BIOs. Call \fISSL_get_error()\fR with the return value \fBret\fR
  186. to find out the reason.
  187. .SH "SEE ALSO"
  188. .IX Header "SEE ALSO"
  189. \&\fISSL_get_error\fR\|(3), \fISSL_connect\fR\|(3),
  190. \&\fISSL_shutdown\fR\|(3), \fIssl\fR\|(3), \fIbio\fR\|(3),
  191. \&\fISSL_set_connect_state\fR\|(3),
  192. \&\fISSL_do_handshake\fR\|(3),
  193. \&\fISSL_CTX_new\fR\|(3)