428 lines
11 KiB
HTML
428 lines
11 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>SSL_Read()--Receive Data from an SSL-Enabled Socket Descriptor</title>
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- Begin Header Records ========================================== -->
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<!-- Direct1 SCRIPT J converted by B2H R4.1 (346) (CMS) by V2KEA304 -->
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<!-- at RCHVMW2 on 17 Feb 1999 at 11:05:09 -->
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<!--End Header Records -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<a name="Top_Of_Page"></a>
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<!-- Java sync-link -->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<h2>SSL_Read()--Receive Data from an SSL-Enabled Socket Descriptor</h2>
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<div class="box" style="width: 60%;">
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<br>
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Syntax<br>
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<pre>
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#include <qsossl.h>
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int SSL_Read(SSLHandle *<em>handle</em>,
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void *<em>buffer</em>,
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int <em>buffer_length</em>)
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</pre>
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<br>
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Service Program Name: QSOSSLSR<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <strong><em>SSL_Read()</em></strong> function is used by a program to
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receive data from an SSL-enabled socket descriptor.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt>SSLHandle* <strong><em>handle</em></strong> (input) </dt>
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<dd>The pointer to an <strong><em>SSLHandle</em></strong> for an SSL session.
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An <strong><em>SSLHandle</em></strong> is a typedef for a buffer of type struct
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<strong><em>SSLHandleStr</em></strong>. In <strong><qsossl.h></strong>,
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struct <strong><em>SSLHandleStr</em></strong> is defined as the following:<br>
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<br>
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<table border cellpadding="5">
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<tr>
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<td>
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<pre>
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struct SSLHandleStr { /* SSLHandleStr */
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int fd; /* Socket descriptor */
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int createFlags; /* SSL_Create flags value */
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unsigned protocol; /* SSL protocol version */
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unsigned timeout; /* Timeout value in seconds */
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unsigned char cipherKind[3]; /* Current 2.0 cipher suite*/
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unsigned short int cipherSuite; /* Current 3.0 cipher suite */
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unsigned short int* cipherSuiteList; /* List of cipher suites */
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unsigned int cipherSuiteListLen; /* Number of entries in
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the cipher suites list */
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unsigned char* peerCert; /* Peer certificate */
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unsigned peerCertLen; /* Peer certificate length */
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int peerCertValidateRc; /* Return code from
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validation of certficate */
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int (*exitPgm)(struct SSLHandleStr* sslh);
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/* Authentication exit
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program called when a
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certificate is received
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during SSL handshake */
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};
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</pre>
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</td>
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</tr>
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</table>
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<br>
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</dd>
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<dt>void *<strong><em>buffer</em></strong> (input) </dt>
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<dd>A pointer to the user-supplied buffer in which the data that is received on
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the SSL session is to be stored.<br>
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<br>
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</dd>
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<dt>int <strong><em>buffer_length</em></strong> (input) </dt>
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<dd>The length of the <em>buffer</em>.</dd>
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</dl>
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<br>
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<h3>Authorities</h3>
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<p>No authorization is required.</p>
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<br>
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<h3>Return Value</h3>
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<p>The <em>SSL_Read()</em> API returns an integer. Possible values are:</p>
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<dl>
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<dt><em>[n]</em> </dt>
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<dd>
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<p>Successful, where n is the number of bytes read. </p>
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</dd>
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<dt><em>[SSL_ERROR_BAD_MESSAGE]</em> </dt>
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<dd>
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<p>SSL received a badly formatted message. </p>
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</dd>
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<dt><em>[SSL_ERROR_BAD_MAC]</em> </dt>
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<dd>
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<p>A bad message authentication code was received. </p>
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</dd>
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<dt><em>[SSL_ERROR_BAD_MALLOC]</em> </dt>
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<dd>
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<p>Unable to allocate storage required for SSL processing. </p>
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</dd>
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<dt><em>[SSL_ERROR_BAD_STATE]</em> </dt>
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<dd>
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<p>SSL detected a bad state in the SSL session. </p>
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</dd>
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<dt><em>[SSL_ERROR_CLOSED]</em> </dt>
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<dd>
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<p>The SSL session ended. </p>
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</dd>
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<dt><em>[SSL_ERROR_IO]</em> </dt>
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<dd>
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<p>An error occurred in SSL processing; check the <em>errno</em> value. </p>
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</dd>
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<dt><em>[SSL_ERROR_PERMISSION_DENIED]</em> </dt>
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<dd>
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<p>Permission was denied to access object. </p>
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</dd>
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<dt><em>[SSL_ERROR_UNKNOWN]</em> </dt>
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<dd>
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<p>An unknown or unexpected error occurred during SSL processing. </p>
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</dd>
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<dt><em>[SSL_ERROR_UNSUPPORTED_CERTIFICATE_TYPE]</em> </dt>
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<dd>
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<p>i5/OS does not support the certificate's type.</p>
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</dd>
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</dl>
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<br>
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<h3>Error Conditions</h3>
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<p>When the <em>SSL_Read()</em> API fails with return code [SSL_ERROR_IO],
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<em>errno</em> can be set to:</p>
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<dl>
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<dt><em>[EBADF]</em> </dt>
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<dd>
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<p>Descriptor not valid. </p>
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</dd>
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<dt><em>[ECONNRESET]</em> </dt>
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<dd>
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<p>A connection with a remote socket was reset by that socket. </p>
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</dd>
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<dt><em>[EFAULT]</em> </dt>
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<dd>
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<p>Bad address.</p>
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<p>One of the following conditions occurred:</p>
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<ul>
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<li>The system detected an address that was not valid while attempting to
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access the <em>buffer</em> parameter.</li>
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<li>The system detected an address that was not valid while attempting to
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access the <em>handle</em> parameter or one of the address fields in the
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<em>handle</em> parameter.</li>
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</ul><br>
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</dd>
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<dt><em>[EINVAL]</em> </dt>
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<dd>
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<p>Parameter not valid.</p>
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<p>This error code indicates one of the following:</p>
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<ul>
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<li>The <em>socket_descriptor</em> type is not SOCK_STREAM or address family is
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not AF_INET or AF_INET6.</li>
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<li>One of the parameters passed is not valid or is NULL.</li>
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<li>The <em>buffer_length</em> parameter specifies a negative value.</li>
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</ul><br>
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</dd>
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<dt><em>[EIO]</em> </dt>
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<dd>
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<p>Input/output error. </p>
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</dd>
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<dt><em>[ENOTCONN]</em> </dt>
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<dd>
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<p>Requested operation requires a connection.</p>
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<p>This error code indicates one of the following:</p>
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<ul>
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<li>The <em>socket_descriptor</em> is not for a socket that is in a connected
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state.</li>
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<li>The <em>socket_descriptor</em> has not had SSL support enabled. This
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usually means that an <em>SSL_Create()</em> has not been completed for this
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<em>socket_descriptor</em>.</li>
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</ul><br>
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</dd>
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<dt><em>[ENOTSOCK]</em></dt>
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<dd>
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<p>The specified descriptor does not reference a socket. </p>
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</dd>
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<dt><em>[ETIMEDOUT]</em></dt>
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<dd>
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<p>A remote host did not respond within the timeout period.</p>
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</dd>
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<dt><em>[EUNATCH]</em></dt>
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<dd>
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<p>The protocol required to support the specified address family is not
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available at this time.</p>
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</dd>
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<dt><em>[EUNKNOWN]</em></dt>
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<dd>
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<p>Unknown system state.</p>
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</dd>
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<dt><em>[EWOULDBLOCK]</em> </dt>
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<dd>
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<p>Operation would have caused the thread to be suspended.</p>
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</dd>
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</dl>
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<br>
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<br>
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<h3>Error Messages</h3>
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<table width="100%" cellpadding="5">
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<tr>
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<th align="left" valign="top">Message ID</th>
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<th align="left" valign="top">Error Message Text</th>
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</tr>
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<tr>
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<td align="left" valign="top">CPE3418 E</td>
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<td align="left" valign="top">Possible APAR condition or hardware failure.</td>
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</tr>
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<tr>
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<td align="left" valign="top">CPF9872 E</td>
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<td align="left" valign="top">Program or service program &1 in library
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&2 ended. Reason code &3.</td>
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</tr>
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<tr>
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<td align="left" valign="top">CPFA081 E</td>
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<td align="left" valign="top">Unable to set return value or error code.</td>
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</tr>
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</table>
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<br><br>
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<h3>Usage Notes</h3>
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<ol>
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<li>The <em>SSL_Read()</em> function is only valid on sockets that have an
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address family of <samp>AF_INET</samp> or <samp>AF_INET6</samp> and a socket type of <samp>SOCK_STREAM</samp>. If the descriptor
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pointed to by the <em>handle</em> structure parameter does not have the correct
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address family and socket type, [SSL_ERROR_IO] is returned and the
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<em>errno</em> value is set to EINVAL.<br>
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<br>
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</li>
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<li>The maximum length of data returned will not exceed 32 KB. This is due to
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the fact that SSL is a record level protocol and the largest record allowed is
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32 KB minus the necessary SSL record headers.<br>
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<br>
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</li>
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<li>If the <em>createFlags</em> field in the <em>SSLHandle</em> specifies a
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value that does not include the SSL_ENCRYPT flag, this function will simply
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call the sockets <em>read()</em> function.<br>
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<br>
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</li>
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<li>Unpredictable results will occur when attempting to mix invocations to
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<em>SSL_Read()</em> and any of the sockets read functions (<em>recv()</em>,
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<em>read()</em>, <em>readv()</em>, and so forth). It is strongly suggested that
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you do not mix the <em>SSL_Read()</em> API with any of the sockets read
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functions.<br>
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<br>
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</li>
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<li>Since SSL is a record-oriented protocol, SSL must receive an entire record
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before it can be decrypted and any data returned to the application. Thus, a
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<em>select()</em> may indicate that data is available to be read, but a
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subsequent <em>SSL_Read()</em> may hang waiting for the remainder of the SSL
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record to be received when using blocking I/O.<br>
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<br>
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</li>
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<li>A FIONREAD <em>ioctl()</em> cannot be used to determine the amount of data
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available for reading by using <em>SSL_Read()</em>.<br>
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<br>
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</li>
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<li>SSL will ignore the out of band (OOB) data indicator. OOB will not affect
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the SSL application. OOB will just be data to the SSL protocol.<br>
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<br>
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</li>
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<li>For an SSL enabled socket, which must use a connection-oriented transport
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service (that is, TCP), a returned value of zero indicates one of the
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following:<br>
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<br>
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<ul>
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<li>The partner program has issued a close() for the socket.</li>
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<li>The partner program has issued a shutdown() to disable writing to the
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socket.</li>
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<li>The connection is broken and the error was returned on a previously issued
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socket function.</li>
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<li>A shutdown() to disable reading was previously done on the socket.</li>
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</ul>
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<br>
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</li>
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<li>If an SSL_Read() is run on a socket that is set to non-blocking mode, and
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there is no data waiting to be read on the SSL enabled socket, the return value
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||
|
|
will be equal to -10 and the errno will be set to EWOULDBLOCK.</li>
|
||
|
|
</ol>
|
||
|
|
|
||
|
|
<br>
|
||
|
|
<h3>Related Information</h3>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li><a href="sslcreat.htm">SSL_Create()</a>--Enable SSL Support for the Specified
|
||
|
|
Socket Descriptor<br>
|
||
|
|
<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="ssldest.htm">SSL_Destroy()</a>--End SSL Support for the Specified SSL
|
||
|
|
Session<br>
|
||
|
|
<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="sslhands.htm">SSL_Handshake()</a>--Initiate the SSL Handshake
|
||
|
|
Protocol<br>
|
||
|
|
<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="sslinit.htm">SSL_Init()</a>--Initialize the Current Job for
|
||
|
|
SSL<br>
|
||
|
|
<br>
|
||
|
|
</li>
|
||
|
|
|
||
|
|
<li><a href="sslwrite.htm">SSL_Write()</a>--Write Data to an SSL-Enabled Socket
|
||
|
|
Descriptor</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<br>
|
||
|
|
<hr>
|
||
|
|
API introduced: V4R3
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<center>
|
||
|
|
<table cellpadding="2" cellspacing="2" align="center">
|
||
|
|
<tr align="center">
|
||
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
|
||
|
|
"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a> </td>
|
||
|
|
</tr>
|
||
|
|
</table></center>
|
||
|
|
</body>
|
||
|
|
</html>
|
||
|
|
|