diff options
author | Bodo Möller <bodo@openssl.org> | 2000-11-12 19:17:22 +0000 |
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committer | Bodo Möller <bodo@openssl.org> | 2000-11-12 19:17:22 +0000 |
commit | 2984b0ae248f876823e8981d3b1bbf9f9bf2e3ff (patch) | |
tree | 5f89f0fc9d0a77422bff9506113954b08ed6fdd0 /doc | |
parent | 3d6001f7b94187d37987cf95385996363e26ca7c (diff) |
Additional explanations for SSL_ERROR_WANT_READ/WRITE.
Diffstat (limited to 'doc')
-rw-r--r-- | doc/ssl/SSL_get_error.pod | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/doc/ssl/SSL_get_error.pod b/doc/ssl/SSL_get_error.pod index d85b564258..747b99741b 100644 --- a/doc/ssl/SSL_get_error.pod +++ b/doc/ssl/SSL_get_error.pod @@ -48,16 +48,26 @@ has been closed. =item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE The operation did not complete; the same TLS/SSL I/O function should be -called again later. There will be protocol progress if, by then, the -underlying B<BIO> has data available for reading (if the result code is -B<SSL_ERROR_WANT_READ>) or allows writing data (B<SSL_ERROR_WANT_WRITE>). -For socket B<BIO>s (e.g. when SSL_set_fd() was used) this means that -select() or poll() on the underlying socket can be used to find out -when the TLS/SSL I/O function should be retried. +called again later. If, by then, the underlying B<BIO> has data +available for reading (if the result code is B<SSL_ERROR_WANT_READ>) +or allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL +protocol progress will take place, i.e. at least part of an TLS/SSL +record will be read or written. Note that the retry may again lead to +a B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition. +There is no fixed upper limit for the number of iterations that +may be necessary until progress becomes visible at application +protocol level. + +For socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or +poll() on the underlying socket can be used to find out when the +TLS/SSL I/O function should be retried. Caveat: Any TLS/SSL I/O function can lead to either of -B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>, i.e. SSL_read() -may want to write data and SSL_write() may want to read data. +B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>. In particular, +SSL_read() may want to write data and SSL_write() may want to read +data. This is because TLS/SSL handshakes may occur at any time +during the protocol (initiated by either the client or the server); +SSL_read() and SSL_write() will handle any pending handshakes. =item SSL_ERROR_WANT_X509_LOOKUP |