Ticket #957:

 - Added SSL socket abstraction with OpenSSL backend.
 - Updated cipher data type and added cipher constants (Symbian SSL socket has also been updated).
 - Updated SIP TLS transport to allow setting certificate/credential (via file).



git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@2950 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 1780 insertions, 0 deletions

diff --git a/pjlib/src/pj/ssl_sock_ossl.c b/pjlib/src/pj/ssl_sock_ossl.c
new file mode 100644
index 00000000..9c6c80c8
--- /dev/null
+++ b/pjlib/src/pj/ssl_sock_ossl.c
@@ -0,0 +1,1780 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2009 Teluu Inc. (http://www.teluu.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+ */
+#include <pj/ssl_sock.h>
+#include <pj/activesock.h>
+#include <pj/compat/socket.h>
+#include <pj/assert.h>
+#include <pj/errno.h>
+#include <pj/list.h>
+#include <pj/lock.h>
+#include <pj/log.h>
+#include <pj/math.h>
+#include <pj/pool.h>
+#include <pj/string.h>
+
+
+/* Only build when PJ_HAS_SSL_SOCK is enabled */
+//#if defined(PJ_HAS_SSL_SOCK) && PJ_HAS_SSL_SOCK!=0
+
+#define THIS_FILE		"ssl_sock_ossl.c"
+
+/* 
+ * Include OpenSSL headers 
+ */
+#include <openssl/bio.h>
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+
+#ifdef _MSC_VER
+# ifdef _DEBUG
+#  pragma comment( lib, "libeay32MTd")
+#  pragma comment( lib, "ssleay32MTd")
+#else
+#  pragma comment( lib, "libeay32MT")
+#  pragma comment( lib, "ssleay32MT")
+# endif
+#endif
+
+
+/*
+ * SSL/TLS state enumeration.
+ */
+enum ssl_state {
+    SSL_STATE_NULL,
+    SSL_STATE_HANDSHAKING,
+    SSL_STATE_ESTABLISHED
+};
+
+/*
+ * Structure of SSL socket read buffer.
+ */
+typedef struct read_data_t
+{
+    void		 *data;
+    pj_size_t		  len;
+} read_data_t;
+
+/*
+ * Get the offset of pointer to read-buffer of SSL socket from read-buffer
+ * of active socket. Note that both SSL socket and active socket employ 
+ * different but correlated read-buffers (as much as async_cnt for each),
+ * and to make it easier/faster to find corresponding SSL socket's read-buffer
+ * from known active socket's read-buffer, the pointer of corresponding 
+ * SSL socket's read-buffer is stored right after the end of active socket's
+ * read-buffer.
+ */
+#define OFFSET_OF_READ_DATA_PTR(ssock, asock_rbuf) \
+					(read_data_t**) \
+					((pj_int8_t*)(asock_rbuf) + \
+					ssock->param.read_buffer_size)
+
+/*
+ * Structure of SSL socket write buffer.
+ */
+typedef struct write_data_t {
+    pj_ioqueue_op_key_t	 key;
+    pj_size_t 	 	 record_len;
+    pj_ioqueue_op_key_t	*app_key;
+    pj_size_t 	 	 plain_data_len;
+    pj_size_t 	 	 data_len;
+    union {
+	char		 content[1];
+	const char	*ptr;
+    } data;
+    unsigned		 flags;
+} write_data_t;
+
+/*
+ * Structure of SSL socket write state.
+ */
+typedef struct write_state_t {
+    char		*buf;
+    pj_size_t		 max_len;    
+    char		*start;
+    pj_size_t		 len;
+    write_data_t	*last_data;
+} write_state_t;
+
+/*
+ * Structure of write data pending.
+ */
+typedef struct write_pending_t {
+    PJ_DECL_LIST_MEMBER(struct write_pending_t);
+    write_data_t	 data;
+} write_pending_t;
+
+/*
+ * Secure socket structure definition.
+ */
+struct pj_ssl_sock_t
+{
+    pj_pool_t		 *pool;
+    pj_ssl_sock_t	 *parent;
+    pj_ssl_sock_param	  param;
+    pj_ssl_cert_t	 *cert;
+
+    pj_bool_t		  is_server;
+    enum ssl_state	  ssl_state;
+    pj_ioqueue_op_key_t	  handshake_op_key;
+
+    pj_sock_t		  sock;
+    pj_activesock_t	 *asock;
+
+    pj_sockaddr		  local_addr;
+    pj_sockaddr		  rem_addr;
+    int			  addr_len;
+    
+    pj_bool_t		  read_started;
+    pj_size_t		  read_size;
+    pj_uint32_t		  read_flags;
+    void		**asock_rbuf;
+    read_data_t		 *ssock_rbuf;
+
+    write_state_t	  write_state;
+    write_pending_t	  write_pending;
+    write_pending_t	  write_pending_empty;
+    pj_lock_t		 *write_mutex; /* protect write BIO and write_state */
+
+    SSL_CTX		 *ossl_ctx;
+    SSL			 *ossl_ssl;
+    BIO			 *ossl_rbio;
+    BIO			 *ossl_wbio;
+};
+
+
+/*
+ * Certificate/credential structure definition.
+ */
+struct pj_ssl_cert_t
+{
+    pj_str_t CA_file;
+    pj_str_t cert_file;
+    pj_str_t privkey_file;
+    pj_str_t privkey_pass;
+};
+
+
+static pj_status_t flush_delayed_send(pj_ssl_sock_t *ssock);
+
+/*
+ *******************************************************************
+ * Static/internal functions.
+ *******************************************************************
+ */
+
+/* ssl_report_error() */
+static void ssl_report_error(const char *sender, int level, 
+			     pj_status_t status,
+			     const char *format, ...)
+{
+    va_list marker;
+
+    va_start(marker, format);
+
+#if PJ_LOG_MAX_LEVEL > 0
+    if (status != PJ_SUCCESS) {
+	char err_format[PJ_ERR_MSG_SIZE + 512];
+	int len;
+
+	len = pj_ansi_snprintf(err_format, sizeof(err_format),
+			       "%s: ", format);
+	pj_strerror(status, err_format+len, sizeof(err_format)-len);
+	
+	pj_log(sender, level, err_format, marker);
+
+    } else {
+	unsigned long ssl_err;
+
+	ssl_err = ERR_get_error();
+
+	if (ssl_err == 0) {
+	    pj_log(sender, level, format, marker);
+	} else {
+	    char err_format[512];
+	    int len;
+
+	    len = pj_ansi_snprintf(err_format, sizeof(err_format),
+				   "%s: ", format);
+	    ERR_error_string(ssl_err, err_format+len);
+	    
+	    pj_log(sender, level, err_format, marker);
+	}
+    }
+#endif
+
+    va_end(marker);
+}
+
+
+
+/* OpenSSL library initialization counter */
+static int openssl_init_count;
+
+/* OpenSSL available ciphers */
+static pj_ssl_cipher openssl_ciphers[64];
+static unsigned openssl_cipher_num;
+
+
+/* Initialize OpenSSL */
+static pj_status_t init_openssl(void)
+{
+    if (++openssl_init_count != 1)
+	return PJ_SUCCESS;
+
+    SSL_library_init();
+    SSL_load_error_strings();
+    OpenSSL_add_all_algorithms();
+
+    /* Init available ciphers */
+    if (openssl_cipher_num == 0) {
+	SSL_METHOD *meth = NULL;
+	SSL_CTX *ctx;
+	SSL *ssl;
+	STACK_OF(SSL_CIPHER) *sk_cipher;
+	unsigned i, n;
+
+	meth = (SSL_METHOD*)SSLv23_server_method();
+	if (!meth)
+	    meth = (SSL_METHOD*)TLSv1_server_method();
+	if (!meth)
+	    meth = (SSL_METHOD*)SSLv3_server_method();
+	if (!meth)
+	    meth = (SSL_METHOD*)SSLv2_server_method();
+	pj_assert(meth);
+
+	ctx=SSL_CTX_new(meth);
+	SSL_CTX_set_cipher_list(ctx, "ALL");
+
+	ssl = SSL_new(ctx);
+	sk_cipher = SSL_get_ciphers(ssl);
+
+	n = sk_SSL_CIPHER_num(sk_cipher);
+	if (n > PJ_ARRAY_SIZE(openssl_ciphers))
+	    n = PJ_ARRAY_SIZE(openssl_ciphers);
+
+	for (i = 0; i < n; ++i) {
+	    SSL_CIPHER *c;
+	    c = sk_SSL_CIPHER_value(sk_cipher,i);
+	    openssl_ciphers[i] = (pj_ssl_cipher)
+				 (pj_uint32_t)c->id & 0x00FFFFFF;
+	    //printf("%3u: %08x=%s\n", i+1, c->id, SSL_CIPHER_get_name(c));
+	}
+
+	SSL_free(ssl);
+	SSL_CTX_free(ctx);
+
+	openssl_cipher_num = n;
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/* Shutdown OpenSSL */
+static void shutdown_openssl(void)
+{
+    if (--openssl_init_count != 0)
+	return;
+}
+
+
+/* SSL password callback. */
+static int password_cb(char *buf, int num, int rwflag, void *user_data)
+{
+    pj_ssl_cert_t *cert = (pj_ssl_cert_t*) user_data;
+
+    PJ_UNUSED_ARG(rwflag);
+
+    if(num < cert->privkey_pass.slen)
+	return 0;
+    
+    pj_memcpy(buf, cert->privkey_pass.ptr, cert->privkey_pass.slen);
+    return cert->privkey_pass.slen;
+}
+
+
+/* Create and initialize new SSL context */
+static pj_status_t create_ssl_ctx(pj_ssl_sock_t *ssock, SSL_CTX **p_ctx)
+{
+    SSL_METHOD *ssl_method;
+    SSL_CTX *ctx;
+    pj_ssl_cert_t *cert;
+    int mode, rc;
+        
+    pj_assert(ssock && p_ctx);
+
+    cert = ssock->cert;
+
+    /* Make sure OpenSSL library has been initialized */
+    init_openssl();
+
+    /* Determine SSL method to use */
+    switch (ssock->param.proto) {
+    case PJ_SSL_SOCK_PROTO_DEFAULT:
+    case PJ_SSL_SOCK_PROTO_TLS1:
+	ssl_method = (SSL_METHOD*)TLSv1_method();
+	break;
+    case PJ_SSL_SOCK_PROTO_SSL2:
+	ssl_method = (SSL_METHOD*)SSLv2_method();
+	break;
+    case PJ_SSL_SOCK_PROTO_SSL3:
+	ssl_method = (SSL_METHOD*)SSLv3_method();
+	break;
+    case PJ_SSL_SOCK_PROTO_SSL23:
+	ssl_method = (SSL_METHOD*)SSLv23_method();
+	break;
+    case PJ_SSL_SOCK_PROTO_DTLS1:
+	ssl_method = (SSL_METHOD*)DTLSv1_method();
+	break;
+    default:
+	ssl_report_error(THIS_FILE, 4, PJ_EINVAL,
+			 "Error creating SSL context");
+	return PJ_EINVAL;
+    }
+
+    /* Create SSL context for the listener */
+    ctx = SSL_CTX_new(ssl_method);
+    if (ctx == NULL) {
+	ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+			 "Error creating SSL context");
+	return PJ_EINVAL;
+    }
+
+    /* Apply credentials */
+    if (cert) {
+	/* Load CA list if one is specified. */
+	if (cert->CA_file.slen) {
+
+	    rc = SSL_CTX_load_verify_locations(ctx, cert->CA_file.ptr, NULL);
+
+	    if (rc != 1) {
+		ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+				 "Error loading/verifying CA list file '%s'",
+				 cert->CA_file.ptr);
+		SSL_CTX_free(ctx);
+		return PJ_EINVAL;
+	    }
+
+	    PJ_LOG(5,(THIS_FILE, "CA file successfully loaded from '%s'",
+		      cert->CA_file.ptr));
+	}
+    
+	/* Set password callback */
+	if (cert->privkey_pass.slen) {
+	    SSL_CTX_set_default_passwd_cb(ctx, password_cb);
+	    SSL_CTX_set_default_passwd_cb_userdata(ctx, cert);
+	}
+
+
+	/* Load certificate if one is specified */
+	if (cert->cert_file.slen) {
+
+	    /* Load certificate chain from file into ctx */
+	    rc = SSL_CTX_use_certificate_chain_file(ctx, cert->cert_file.ptr);
+
+	    if(rc != 1) {
+		ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+				 "Error loading certificate chain file '%s'",
+				 cert->cert_file.ptr);
+		SSL_CTX_free(ctx);
+		return PJ_EINVAL;
+	    }
+
+	    PJ_LOG(5,(THIS_FILE, "TLS certificate successfully loaded from '%s'",
+		      cert->cert_file.ptr));
+	}
+
+
+	/* Load private key if one is specified */
+	if (cert->privkey_file.slen) {
+	    /* Adds the first private key found in file to ctx */
+	    rc = SSL_CTX_use_PrivateKey_file(ctx, cert->privkey_file.ptr, 
+					     SSL_FILETYPE_PEM);
+
+	    if(rc != 1) {
+		ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+				 "Error adding private key from '%s'",
+				 cert->privkey_file.ptr);
+		SSL_CTX_free(ctx);
+		return PJ_EINVAL;
+	    }
+
+	    PJ_LOG(5,(THIS_FILE, "Private key successfully loaded from '%s'",
+		      cert->privkey_file.ptr));
+	}
+    }
+
+
+    /* SSL verification options */
+    if (ssock->param.verify_peer) {
+	mode = SSL_VERIFY_PEER;
+    } else {
+	mode = SSL_VERIFY_NONE;
+    }
+
+    if (ssock->is_server && ssock->param.require_client_cert)
+	mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
+
+    SSL_CTX_set_verify(ctx, mode, NULL);
+
+    PJ_LOG(5,(THIS_FILE, "Verification mode set to %d", mode));
+
+    *p_ctx = ctx;
+
+    return PJ_SUCCESS;
+}
+
+
+/* Destroy SSL context */
+static void destroy_ssl_ctx(SSL_CTX *ctx)
+{
+    SSL_CTX_free(ctx);
+
+    /* Potentially shutdown OpenSSL library if this is the last
+     * context exists.
+     */
+    shutdown_openssl();
+}
+
+
+/* Reset SSL socket state */
+static void reset_ssl_sock_state(pj_ssl_sock_t *ssock)
+{
+    ssock->ssl_state = SSL_STATE_NULL;
+
+    if (ssock->ossl_ssl) {
+	SSL_shutdown(ssock->ossl_ssl);
+	SSL_free(ssock->ossl_ssl); /* this will also close BIOs */
+	ssock->ossl_ssl = NULL;
+    }
+    if (ssock->ossl_ctx) {
+	destroy_ssl_ctx(ssock->ossl_ctx);
+	ssock->ossl_ctx = NULL;
+    }
+    if (ssock->asock) {
+	pj_activesock_close(ssock->asock);
+	ssock->asock = NULL;
+	ssock->sock = PJ_INVALID_SOCKET;
+    }
+}
+
+
+/* Generate cipher list with user preference order in OpenSSL format */
+static pj_status_t set_cipher_list(pj_ssl_sock_t *ssock)
+{
+    char buf[1024];
+    pj_str_t cipher_list;
+    STACK_OF(SSL_CIPHER) *sk_cipher;
+    unsigned i;
+    int j, ret;
+
+    if (ssock->param.ciphers_num == 0)
+	return PJ_SUCCESS;
+
+    pj_strset(&cipher_list, buf, 0);
+
+    /* Set SSL with ALL available ciphers */
+    SSL_set_cipher_list(ssock->ossl_ssl, "ALL");
+
+    /* Generate user specified cipher list in OpenSSL format */
+    sk_cipher = SSL_get_ciphers(ssock->ossl_ssl);
+    for (i = 0; i < ssock->param.ciphers_num; ++i) {
+	for (j = 0; j < sk_SSL_CIPHER_num(sk_cipher); ++j) {
+	    SSL_CIPHER *c;
+	    c = sk_SSL_CIPHER_value(sk_cipher, j);
+	    if (ssock->param.ciphers[i] == (pj_ssl_cipher)
+					   ((pj_uint32_t)c->id & 0x00FFFFFF))
+	    {
+		const char *c_name;
+
+		c_name = SSL_CIPHER_get_name(c);
+
+		/* Check buffer size */
+		if (cipher_list.slen + pj_ansi_strlen(c_name) + 2 > sizeof(buf)) {
+		    pj_assert(!"Insufficient temporary buffer for cipher");
+		    return PJ_ETOOMANY;
+		}
+
+		/* Add colon separator */
+		if (cipher_list.slen)
+		    pj_strcat2(&cipher_list, ":");
+
+		/* Add the cipher */
+		pj_strcat2(&cipher_list, c_name);
+		break;
+	    }
+	}
+    }
+
+    /* Put NULL termination in the generated cipher list */
+    cipher_list.ptr[cipher_list.slen] = '\0';
+
+    /* Finally, set chosen cipher list */
+    ret = SSL_set_cipher_list(ssock->ossl_ssl, buf);
+    if (ret < 1) {
+	ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+			 "Error setting cipher list");
+	return PJ_EINVAL;
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/* When handshake completed:
+ * - notify application
+ * - if handshake failed, reset SSL state
+ * - return PJ_FALSE when SSL socket instance is destroyed by application.
+ */
+static pj_bool_t on_handshake_complete(pj_ssl_sock_t *ssock, 
+				       pj_status_t status)
+{
+    /* Accepting */
+    if (ssock->is_server) {
+	if (status != PJ_SUCCESS) {
+	    /* Handshake failed in accepting, destroy our self silently. */
+	    pj_ssl_sock_close(ssock);
+	    return PJ_FALSE;
+	}
+	/* Notify application the newly accepted SSL socket */
+	if (ssock->param.cb.on_accept_complete) {
+	    pj_bool_t ret;
+	    ret = (*ssock->param.cb.on_accept_complete)
+		      (ssock->parent, ssock, (pj_sockaddr_t*)&ssock->rem_addr,
+		       pj_sockaddr_get_len((pj_sockaddr_t*)&ssock->rem_addr));
+	    if (ret == PJ_FALSE)
+		return PJ_FALSE;
+	}
+    }
+
+    /* Connecting */
+    else {
+	if (ssock->param.cb.on_connect_complete) {
+	    pj_bool_t ret;
+	    ret = (*ssock->param.cb.on_connect_complete)(ssock, status);
+	    if (ret == PJ_FALSE)
+		return PJ_FALSE;
+	}
+	if (status != PJ_SUCCESS) {
+	    /* Reset SSL socket state */
+	    reset_ssl_sock_state(ssock);
+	}
+    }
+
+    return PJ_TRUE;
+}
+
+/* Flush write BIO to network socket. Note that any access to write BIO
+ * MUST be serialized, so mutex protection must cover any call to OpenSSL
+ * API (that possibly generate data for write BIO) along with the call to
+ * this function (flushing all data in write BIO generated by above 
+ * OpenSSL API call).
+ */
+static pj_status_t flush_write_bio(pj_ssl_sock_t *ssock, 
+				   pj_ioqueue_op_key_t *send_key,
+				   pj_size_t orig_len,
+				   unsigned flags)
+{
+    char *data;
+    pj_ssize_t len;
+
+    write_state_t *write_st = &ssock->write_state;
+    write_data_t *wdata;
+    pj_size_t avail_len, needed_len, skipped_len = 0;
+    pj_status_t status;
+
+    /* Check if there is data in write BIO, flush it if any */
+    if (!BIO_pending(ssock->ossl_wbio))
+	return PJ_SUCCESS;
+
+    /* Get data and its length */
+    len = BIO_get_mem_data(ssock->ossl_wbio, &data);
+    if (len == 0)
+	return PJ_SUCCESS;
+
+    /* Calculate buffer size needed, and align it to 8 */
+    needed_len = len + sizeof(write_data_t);
+    needed_len = ((needed_len + 7) >> 3) << 3;
+
+    /* Check buffer availability */
+    avail_len = write_st->max_len - write_st->len;
+    if (avail_len < needed_len)
+	return PJ_ENOMEM;
+
+    /* More buffer availability check, note that the write data must be in
+     * a contigue buffer.
+     */
+    if (write_st->len == 0) {
+
+	write_st->start = write_st->buf;
+	wdata = (write_data_t*)write_st->start;
+
+    } else {
+
+	char *reg1, *reg2;
+	pj_size_t reg1_len, reg2_len;
+
+	/* Unused slots may be wrapped/splitted into two regions, so let's
+	 * analyze them if any region can hold the write data.
+	 */
+	reg1 = write_st->start + write_st->len;
+	if (reg1 >= write_st->buf + write_st->max_len)
+	    reg1 -= write_st->max_len;
+	reg1_len = write_st->max_len - write_st->len;
+	if (reg1 + reg1_len > write_st->buf + write_st->max_len) {
+	    reg1_len = write_st->buf + write_st->max_len - reg1;
+	    reg2 = write_st->buf;
+	    reg2_len = write_st->start - write_st->buf;
+	} else {
+	    reg2 = NULL;
+	    reg2_len = 0;
+	}
+	avail_len = PJ_MAX(reg1_len, reg2_len);
+	if (avail_len < needed_len)
+	    return PJ_ENOMEM;
+
+	/* Get write data pointer and update buffer length */
+	if (reg1_len >= needed_len) {
+	    wdata = (write_data_t*)reg1;
+	} else {
+	    wdata = (write_data_t*)reg2;
+	    /* Unused slot in region 1 is skipped as current write data
+	     * doesn't fit it.
+	     */
+	    skipped_len = reg1_len;
+	}
+    }
+
+    /* Copy the data and set its properties into the buffer */
+    pj_bzero(wdata, sizeof(write_data_t));
+    wdata->app_key = send_key;
+    wdata->record_len = needed_len;
+    wdata->data_len = len;
+    wdata->plain_data_len = orig_len;
+    wdata->flags = flags;
+    pj_memcpy(&wdata->data, data, len);
+
+    /* Send it */
+    if (ssock->param.sock_type == pj_SOCK_STREAM()) {
+	status = pj_activesock_send(ssock->asock, &wdata->key, 
+				    wdata->data.content, &len,
+				    flags);
+    } else {
+	status = pj_activesock_sendto(ssock->asock, &wdata->key, 
+				      wdata->data.content, &len,
+				      flags,
+				      (pj_sockaddr_t*)&ssock->rem_addr,
+				      ssock->addr_len);
+    }
+
+    /* Oh no, EWOULDBLOCK! */
+    if (status == PJ_STATUS_FROM_OS(OSERR_EWOULDBLOCK)) {
+	/* Just return PJ_SUCCESS here, the pending data will be sent in next
+	 * call of this function since the data is still stored in write BIO.
+	 */
+	return PJ_SUCCESS;
+    }
+
+    /* Reset write BIO after flushed */
+    BIO_reset(ssock->ossl_wbio);
+
+    if (status == PJ_EPENDING) {
+	/* Update write state */
+	pj_assert(skipped_len==0 || write_st->last_data);
+	write_st->len += needed_len + skipped_len;
+	if (write_st->last_data)
+	    write_st->last_data->record_len += skipped_len;
+	write_st->last_data = wdata;
+    }
+
+    return status;
+}
+
+static pj_status_t do_handshake(pj_ssl_sock_t *ssock)
+{
+    pj_status_t status;
+    int err;
+
+    pj_lock_acquire(ssock->write_mutex);
+
+    /* Perform SSL handshake */
+    err = SSL_do_handshake(ssock->ossl_ssl);
+    if (err < 0) {
+	err = SSL_get_error(ssock->ossl_ssl, err);
+	if (err != SSL_ERROR_NONE && err != SSL_ERROR_WANT_READ) 
+	{
+	    /* Handshake fails */
+	    ssl_report_error(THIS_FILE, 4, PJ_SUCCESS, 
+			     "SSL_do_handshake()");
+	    pj_lock_release(ssock->write_mutex);
+	    return PJ_ECANCELLED;
+	}
+    }
+
+    /* SSL_do_handshake() may put some pending data into SSL write BIO, 
+     * flush it if any.
+     */
+    status = flush_write_bio(ssock, &ssock->handshake_op_key, 0, 0);
+    if (status != PJ_SUCCESS && status != PJ_EPENDING) {
+	pj_lock_release(ssock->write_mutex);
+	return status;
+    }
+
+    pj_lock_release(ssock->write_mutex);
+
+    /* Check if handshake has been completed */
+    if (SSL_is_init_finished(ssock->ossl_ssl)) {
+	ssock->ssl_state = SSL_STATE_ESTABLISHED;
+	return PJ_SUCCESS;
+    }
+
+    return PJ_EPENDING;
+}
+
+
+/*
+ *******************************************************************
+ * Active socket callbacks.
+ *******************************************************************
+ */
+
+static pj_bool_t asock_on_data_read (pj_activesock_t *asock,
+				     void *data,
+				     pj_size_t size,
+				     pj_status_t status,
+				     pj_size_t *remainder)
+{
+    pj_ssl_sock_t *ssock = (pj_ssl_sock_t*)
+			   pj_activesock_get_user_data(asock);
+    pj_size_t nwritten;
+
+    /* Socket error or closed */
+    if (data == NULL || size < 0)
+	goto on_error;
+
+    /* Consume the whole data */
+    nwritten = BIO_write(ssock->ossl_rbio, data, size);
+    if (nwritten < size) {
+	status = PJ_ENOMEM;
+	ssl_report_error(THIS_FILE, 4, PJ_SUCCESS, "BIO_write()");
+	goto on_error;
+    }
+
+    /* Check if SSL handshake hasn't finished yet */
+    if (ssock->ssl_state == SSL_STATE_HANDSHAKING) {
+	pj_bool_t ret = PJ_TRUE;
+
+	if (status == PJ_SUCCESS)
+	    status = do_handshake(ssock);
+
+	/* Not pending is either success or failed */
+	if (status != PJ_EPENDING)
+	    ret = on_handshake_complete(ssock, status);
+
+	return ret;
+    }
+
+    /* See if there is any decrypted data for the application */
+    if (ssock->read_started) {
+	do {
+	    read_data_t *buf = *(OFFSET_OF_READ_DATA_PTR(ssock, data));
+	    void *data_ = (pj_int8_t*)buf->data + buf->len;
+	    int size_ = ssock->read_size - buf->len;
+
+	    /* SSL_read() may write some data to BIO write when re-negotiation
+	     * is on progress, so let's protect it with write mutex.
+	     */
+	    pj_lock_acquire(ssock->write_mutex);
+
+	    size_ = SSL_read(ssock->ossl_ssl, data_, size_);
+	    if (size_ > 0) {
+		pj_lock_release(ssock->write_mutex);
+		if (ssock->param.cb.on_data_read) {
+		    pj_bool_t ret;
+		    pj_size_t remainder_ = 0;
+
+		    buf->len += size_;
+    		
+		    ret = (*ssock->param.cb.on_data_read)(ssock, buf->data,
+							  buf->len, status,
+							  &remainder_);
+		    if (!ret) {
+			/* We've been destroyed */
+			return PJ_FALSE;
+		    }
+
+		    /* Application may have left some data to be consumed 
+		     * later.
+		     */
+		    buf->len = remainder_;
+		}
+	    } else {
+		int err = SSL_get_error(ssock->ossl_ssl, size);
+		
+		/* SSL might just return SSL_ERROR_WANT_READ in 
+		 * re-negotiation.
+		 */
+		if (err != SSL_ERROR_NONE && err != SSL_ERROR_WANT_READ)
+		{
+		    /* Reset SSL socket state, then return PJ_FALSE */
+		    ssl_report_error(THIS_FILE, 4, PJ_SUCCESS, "SSL_read()");
+		    pj_lock_release(ssock->write_mutex);
+		    reset_ssl_sock_state(ssock);
+		    return PJ_FALSE;
+		}
+
+		/* SSL may write something in case of re-negotiation */
+		status = flush_write_bio(ssock, &ssock->handshake_op_key, 0, 0);
+		pj_lock_release(ssock->write_mutex);
+		if (status != PJ_SUCCESS && status != PJ_EPENDING)
+		    goto on_error;
+
+		/* If re-negotiation has been completed, start flushing
+		 * delayed send.
+		 */
+		if (!SSL_renegotiate_pending(ssock->ossl_ssl)) {
+		    status = flush_delayed_send(ssock);
+		    if (status != PJ_SUCCESS && status != PJ_EPENDING)
+			goto on_error;
+		}
+
+		break;
+	    }
+	} while (1);
+    }
+
+    return PJ_TRUE;
+
+on_error:
+    if (ssock->ssl_state == SSL_STATE_HANDSHAKING)
+	return on_handshake_complete(ssock, status);
+
+    if (ssock->read_started && ssock->param.cb.on_data_read) {
+	pj_bool_t ret;
+	ret = (*ssock->param.cb.on_data_read)(ssock, NULL, 0, status,
+					      remainder);
+	if (!ret) {
+	    /* We've been destroyed */
+	    return PJ_FALSE;
+	}
+    }
+
+    reset_ssl_sock_state(ssock);
+    return PJ_FALSE;
+}
+
+
+static pj_bool_t asock_on_data_sent (pj_activesock_t *asock,
+				     pj_ioqueue_op_key_t *send_key,
+				     pj_ssize_t sent)
+{
+    pj_ssl_sock_t *ssock = (pj_ssl_sock_t*)
+			   pj_activesock_get_user_data(asock);
+
+    PJ_UNUSED_ARG(send_key);
+    PJ_UNUSED_ARG(sent);
+
+    if (ssock->ssl_state == SSL_STATE_HANDSHAKING) {
+	/* Initial handshaking */
+	pj_status_t status;
+	
+	status = do_handshake(ssock);
+	/* Not pending is either success or failed */
+	if (status != PJ_EPENDING)
+	    return on_handshake_complete(ssock, status);
+
+    } else if (send_key != &ssock->handshake_op_key) {
+	/* Some data has been sent, notify application */
+	write_data_t *wdata = (write_data_t*)send_key;
+	if (ssock->param.cb.on_data_sent) {
+	    pj_bool_t ret;
+	    ret = (*ssock->param.cb.on_data_sent)(ssock, wdata->app_key, 
+						  wdata->plain_data_len);
+	    if (!ret) {
+		/* We've been destroyed */
+		return PJ_FALSE;
+	    }
+	}
+
+	/* Update write buffer state */
+	pj_lock_acquire(ssock->write_mutex);
+	ssock->write_state.start += wdata->record_len;
+	ssock->write_state.len -= wdata->record_len;
+	if (ssock->write_state.last_data == wdata) {
+	    pj_assert(ssock->write_state.len == 0);
+	    ssock->write_state.last_data = NULL;
+	}
+	pj_lock_release(ssock->write_mutex);
+
+    } else {
+	/* SSL re-negotiation is on-progress, just do nothing */
+    }
+
+    return PJ_TRUE;
+}
+
+
+static pj_bool_t asock_on_accept_complete (pj_activesock_t *asock,
+					   pj_sock_t newsock,
+					   const pj_sockaddr_t *src_addr,
+					   int src_addr_len)
+{
+    pj_ssl_sock_t *ssock_parent = (pj_ssl_sock_t*)
+				  pj_activesock_get_user_data(asock);
+    pj_ssl_sock_t *ssock;
+    pj_activesock_cb asock_cb;
+    pj_activesock_cfg asock_cfg;
+    unsigned i;
+    pj_status_t status;
+
+    PJ_UNUSED_ARG(src_addr_len);
+
+    /* Create new SSL socket instance */
+    status = pj_ssl_sock_create(ssock_parent->pool, &ssock_parent->param,
+				&ssock);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Update new SSL socket attributes */
+    ssock->sock = newsock;
+    ssock->parent = ssock_parent;
+    ssock->is_server = PJ_TRUE;
+    if (ssock_parent->cert) {
+	status = pj_ssl_sock_set_certificate(ssock, ssock->pool, 
+					     ssock_parent->cert);
+	if (status != PJ_SUCCESS)
+	    goto on_return;
+    }
+
+    /* Update local address */
+    ssock->addr_len = src_addr_len;
+    status = pj_sock_getsockname(ssock->sock, &ssock->local_addr, 
+				 &ssock->addr_len);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Set remote address */
+    pj_sockaddr_cp(&ssock->rem_addr, src_addr);
+
+    /* Create SSL context */
+    status = create_ssl_ctx(ssock, &ssock->ossl_ctx);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Create SSL instance */
+    ssock->ossl_ssl = SSL_new(ssock->ossl_ctx);
+    if (ssock->ossl_ssl == NULL) {
+	ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+			 "Error creating SSL connection object");
+	status = PJ_EINVAL;
+	goto on_return;
+    }
+
+    /* Set cipher list */
+    status = set_cipher_list(ssock);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Setup SSL BIOs */
+    ssock->ossl_rbio = BIO_new(BIO_s_mem());
+    ssock->ossl_wbio = BIO_new(BIO_s_mem());
+    BIO_set_close(ssock->ossl_rbio, BIO_CLOSE);
+    BIO_set_close(ssock->ossl_wbio, BIO_CLOSE);
+    SSL_set_bio(ssock->ossl_ssl, ssock->ossl_rbio, ssock->ossl_wbio);
+
+    /* Prepare read buffer */
+    ssock->asock_rbuf = (void**)pj_pool_calloc(ssock->pool, 
+					       ssock->param.async_cnt,
+					       sizeof(void*));
+    for (i = 0; i<ssock->param.async_cnt; ++i) {
+	ssock->asock_rbuf[i] = (void*) pj_pool_alloc(
+					    ssock->pool, 
+					    ssock->param.read_buffer_size + 
+					    sizeof(read_data_t*));
+    }
+
+    /* Create active socket */
+    pj_activesock_cfg_default(&asock_cfg);
+    asock_cfg.async_cnt = ssock->param.async_cnt;
+    asock_cfg.concurrency = ssock->param.concurrency;
+    asock_cfg.whole_data = PJ_TRUE;
+
+    pj_bzero(&asock_cb, sizeof(asock_cb));
+    asock_cb.on_data_read = asock_on_data_read;
+    asock_cb.on_data_sent = asock_on_data_sent;
+
+    status = pj_activesock_create(ssock->pool,
+				  ssock->sock, 
+				  ssock->param.sock_type,
+				  &asock_cfg,
+				  ssock->param.ioqueue, 
+				  &asock_cb,
+				  ssock,
+				  &ssock->asock);
+
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Start read */
+    status = pj_activesock_start_read2(ssock->asock, ssock->pool, 
+				       ssock->param.read_buffer_size,
+				       ssock->asock_rbuf,
+				       PJ_IOQUEUE_ALWAYS_ASYNC);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Prepare write/send state */
+    pj_assert(ssock->write_state.max_len == 0);
+    ssock->write_state.buf = (char*)
+			     pj_pool_alloc(ssock->pool, 
+					   ssock->param.send_buffer_size);
+    ssock->write_state.max_len = ssock->param.send_buffer_size;
+    ssock->write_state.start = ssock->write_state.buf;
+    ssock->write_state.len = 0;
+
+    /* Start SSL handshake */
+    ssock->ssl_state = SSL_STATE_HANDSHAKING;
+    SSL_set_accept_state(ssock->ossl_ssl);
+    status = do_handshake(ssock);
+    if (status != PJ_EPENDING)
+	goto on_return;
+
+    return PJ_TRUE;
+
+on_return:
+    return on_handshake_complete(ssock, status);
+}
+
+
+static pj_bool_t asock_on_connect_complete (pj_activesock_t *asock,
+					    pj_status_t status)
+{
+    pj_ssl_sock_t *ssock = (pj_ssl_sock_t*)
+			   pj_activesock_get_user_data(asock);
+    unsigned i;
+
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Update local address */
+    ssock->addr_len = sizeof(pj_sockaddr);
+    status = pj_sock_getsockname(ssock->sock, &ssock->local_addr, 
+				 &ssock->addr_len);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Create SSL context */
+    status = create_ssl_ctx(ssock, &ssock->ossl_ctx);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Create SSL instance */
+    ssock->ossl_ssl = SSL_new(ssock->ossl_ctx);
+    if (ssock->ossl_ssl == NULL) {
+	ssl_report_error(THIS_FILE, 4, PJ_SUCCESS,
+			 "Error creating SSL connection object");
+	status = PJ_EINVAL;
+	goto on_return;
+    }
+
+    /* Set cipher list */
+    status = set_cipher_list(ssock);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Setup SSL BIOs */
+    ssock->ossl_rbio = BIO_new(BIO_s_mem());
+    ssock->ossl_wbio = BIO_new(BIO_s_mem());
+    BIO_set_close(ssock->ossl_rbio, BIO_CLOSE);
+    BIO_set_close(ssock->ossl_wbio, BIO_CLOSE);
+    SSL_set_bio(ssock->ossl_ssl, ssock->ossl_rbio, ssock->ossl_wbio);
+
+    /* Prepare read buffer */
+    ssock->asock_rbuf = (void**)pj_pool_calloc(ssock->pool, 
+					       ssock->param.async_cnt,
+					       sizeof(void*));
+    for (i = 0; i<ssock->param.async_cnt; ++i) {
+	ssock->asock_rbuf[i] = (void*) pj_pool_alloc(
+					    ssock->pool, 
+					    ssock->param.read_buffer_size + 
+					    sizeof(read_data_t*));
+    }
+
+    /* Start read */
+    status = pj_activesock_start_read2(ssock->asock, ssock->pool, 
+				       ssock->param.read_buffer_size,
+				       ssock->asock_rbuf,
+				       PJ_IOQUEUE_ALWAYS_ASYNC);
+    if (status != PJ_SUCCESS)
+	goto on_return;
+
+    /* Prepare write/send state */
+    pj_assert(ssock->write_state.max_len == 0);
+    ssock->write_state.buf = (char*)
+			     pj_pool_alloc(ssock->pool, 
+					   ssock->param.send_buffer_size);
+    ssock->write_state.max_len = ssock->param.send_buffer_size;
+    ssock->write_state.start = ssock->write_state.buf;
+    ssock->write_state.len = 0;
+
+    /* Start SSL handshake */
+    ssock->ssl_state = SSL_STATE_HANDSHAKING;
+    SSL_set_connect_state(ssock->ossl_ssl);
+    status = do_handshake(ssock);
+    if (status != PJ_EPENDING)
+	goto on_return;
+
+    return PJ_TRUE;
+
+on_return:
+    return on_handshake_complete(ssock, status);
+}
+
+
+
+/*
+ *******************************************************************
+ * API
+ *******************************************************************
+ */
+
+/* Load credentials from files. */
+PJ_DEF(pj_status_t) pj_ssl_cert_load_from_files (pj_pool_t *pool,
+						 const pj_str_t *CA_file,
+						 const pj_str_t *cert_file,
+						 const pj_str_t *privkey_file,
+						 const pj_str_t *privkey_pass,
+						 pj_ssl_cert_t **p_cert)
+{
+    pj_ssl_cert_t *cert;
+
+    PJ_ASSERT_RETURN(pool && CA_file && cert_file && privkey_file, PJ_EINVAL);
+
+    cert = PJ_POOL_ZALLOC_T(pool, pj_ssl_cert_t);
+    pj_strdup_with_null(pool, &cert->CA_file, CA_file);
+    pj_strdup_with_null(pool, &cert->cert_file, cert_file);
+    pj_strdup_with_null(pool, &cert->privkey_file, privkey_file);
+    pj_strdup_with_null(pool, &cert->privkey_pass, privkey_pass);
+
+    *p_cert = cert;
+
+    return PJ_SUCCESS;
+}
+
+
+/* Set SSL socket credentials. */
+PJ_DECL(pj_status_t) pj_ssl_sock_set_certificate(
+					    pj_ssl_sock_t *ssock,
+					    pj_pool_t *pool,
+					    const pj_ssl_cert_t *cert)
+{
+    PJ_ASSERT_RETURN(ssock && pool && cert, PJ_EINVAL);
+
+    ssock->cert = PJ_POOL_ZALLOC_T(pool, pj_ssl_cert_t);
+    pj_strdup_with_null(pool, &ssock->cert->CA_file, &cert->CA_file);
+    pj_strdup_with_null(pool, &ssock->cert->cert_file, &cert->cert_file);
+    pj_strdup_with_null(pool, &ssock->cert->privkey_file, &cert->privkey_file);
+    pj_strdup_with_null(pool, &ssock->cert->privkey_pass, &cert->privkey_pass);
+
+    return PJ_SUCCESS;
+}
+
+
+/* Get available ciphers. */
+PJ_DEF(pj_status_t) pj_ssl_cipher_get_availables(pj_ssl_cipher ciphers[],
+					         unsigned *cipher_num)
+{
+    unsigned i;
+
+    PJ_ASSERT_RETURN(ciphers && cipher_num, PJ_EINVAL);
+
+    if (openssl_cipher_num == 0) {
+	init_openssl();
+	shutdown_openssl();
+    }
+
+    if (openssl_cipher_num == 0)
+	return PJ_ENOTFOUND;
+
+    *cipher_num = PJ_MIN(*cipher_num, openssl_cipher_num);
+
+    for (i = 0; i < *cipher_num; ++i)
+	ciphers[i] = openssl_ciphers[i];
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Create SSL socket instance. 
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_create (pj_pool_t *pool,
+					const pj_ssl_sock_param *param,
+					pj_ssl_sock_t **p_ssock)
+{
+    pj_ssl_sock_t *ssock;
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(pool && param && p_ssock, PJ_EINVAL);
+    PJ_ASSERT_RETURN(param->sock_type == pj_SOCK_STREAM(), PJ_ENOTSUP);
+
+    pool = pj_pool_create(pool->factory, "ssl%p", 512, 512, NULL);
+
+    /* Create secure socket */
+    ssock = PJ_POOL_ZALLOC_T(pool, pj_ssl_sock_t);
+    ssock->pool = pool;
+    ssock->sock = PJ_INVALID_SOCKET;
+    ssock->ssl_state = SSL_STATE_NULL;
+    pj_list_init(&ssock->write_pending);
+    pj_list_init(&ssock->write_pending_empty);
+
+    /* Create secure socket mutex */
+    status = pj_lock_create_recursive_mutex(pool, pool->obj_name,
+					    &ssock->write_mutex);
+    if (status != PJ_SUCCESS)
+	return status;
+
+    /* Init secure socket param */
+    ssock->param = *param;
+    ssock->param.read_buffer_size = ((ssock->param.read_buffer_size+7)>>3)<<3;
+    if (param->ciphers_num > 0) {
+	unsigned i;
+	ssock->param.ciphers = (pj_ssl_cipher*)
+			       pj_pool_calloc(pool, param->ciphers_num, 
+					      sizeof(pj_ssl_cipher));
+	for (i = 0; i < param->ciphers_num; ++i)
+	    ssock->param.ciphers[i] = param->ciphers[i];
+    }
+    pj_strdup_with_null(pool, &ssock->param.servername, 
+			&param->servername);
+
+    /* Finally */
+    *p_ssock = ssock;
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Close the secure socket. This will unregister the socket from the
+ * ioqueue and ultimately close the socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_close(pj_ssl_sock_t *ssock)
+{
+    pj_pool_t *pool;
+
+    PJ_ASSERT_RETURN(ssock, PJ_EINVAL);
+
+    reset_ssl_sock_state(ssock);
+    pj_lock_destroy(ssock->write_mutex);
+    
+    pool = ssock->pool;
+    ssock->pool = NULL;
+    if (pool)
+	pj_pool_release(pool);
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Associate arbitrary data with the secure socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_set_user_data(pj_ssl_sock_t *ssock,
+					      void *user_data)
+{
+    PJ_ASSERT_RETURN(ssock, PJ_EINVAL);
+
+    ssock->param.user_data = user_data;
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Retrieve the user data previously associated with this secure
+ * socket.
+ */
+PJ_DEF(void*) pj_ssl_sock_get_user_data(pj_ssl_sock_t *ssock)
+{
+    PJ_ASSERT_RETURN(ssock, NULL);
+
+    return ssock->param.user_data;
+}
+
+
+/*
+ * Retrieve the local address and port used by specified SSL socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_get_info (pj_ssl_sock_t *ssock,
+					  pj_ssl_sock_info *info)
+{
+    pj_bzero(info, sizeof(*info));
+
+    /* Established flag */
+    info->established = (ssock->ssl_state == SSL_STATE_ESTABLISHED);
+
+    /* Protocol */
+    info->proto = ssock->param.proto;
+
+    /* Local address */
+    pj_sockaddr_cp(&info->local_addr, &ssock->local_addr);
+    
+    if (info->established) {
+	/* Current cipher */
+	const SSL_CIPHER *cipher;
+
+	cipher = SSL_get_current_cipher(ssock->ossl_ssl);
+	info->cipher = (cipher->id & 0x00FFFFFF);
+
+	/* Remote address */
+	pj_sockaddr_cp(&info->remote_addr, &ssock->rem_addr);
+    }
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Starts read operation on this secure socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_start_read (pj_ssl_sock_t *ssock,
+					    pj_pool_t *pool,
+					    unsigned buff_size,
+					    pj_uint32_t flags)
+{
+    void **readbuf;
+    unsigned i;
+
+    PJ_ASSERT_RETURN(ssock && pool && buff_size, PJ_EINVAL);
+    PJ_ASSERT_RETURN(ssock->ssl_state==SSL_STATE_ESTABLISHED, PJ_EINVALIDOP);
+
+    readbuf = (void**) pj_pool_calloc(pool, ssock->param.async_cnt, 
+				      sizeof(void*));
+
+    for (i=0; i<ssock->param.async_cnt; ++i) {
+	readbuf[i] = pj_pool_alloc(pool, buff_size);
+    }
+
+    return pj_ssl_sock_start_read2(ssock, pool, buff_size, 
+				   readbuf, flags);
+}
+
+
+/*
+ * Same as #pj_ssl_sock_start_read(), except that the application
+ * supplies the buffers for the read operation so that the acive socket
+ * does not have to allocate the buffers.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_start_read2 (pj_ssl_sock_t *ssock,
+					     pj_pool_t *pool,
+					     unsigned buff_size,
+					     void *readbuf[],
+					     pj_uint32_t flags)
+{
+    unsigned i;
+
+    PJ_ASSERT_RETURN(ssock && pool && buff_size && readbuf, PJ_EINVAL);
+    PJ_ASSERT_RETURN(ssock->ssl_state==SSL_STATE_ESTABLISHED, PJ_EINVALIDOP);
+
+    /* Create SSL socket read buffer */
+    ssock->ssock_rbuf = (read_data_t*)pj_pool_calloc(pool, 
+					       ssock->param.async_cnt,
+					       sizeof(read_data_t));
+
+    /* Store SSL socket read buffer pointer in the activesock read buffer */
+    for (i=0; i<ssock->param.async_cnt; ++i) {
+	read_data_t **p_ssock_rbuf = 
+			OFFSET_OF_READ_DATA_PTR(ssock, ssock->asock_rbuf[i]);
+
+	ssock->ssock_rbuf[i].data = readbuf[i];
+	ssock->ssock_rbuf[i].len = 0;
+
+	*p_ssock_rbuf = &ssock->ssock_rbuf[i];
+    }
+
+    ssock->read_size = buff_size;
+    ssock->read_started = PJ_TRUE;
+    ssock->read_flags = flags;
+
+    return PJ_SUCCESS;
+}
+
+
+/*
+ * Same as pj_ssl_sock_start_read(), except that this function is used
+ * only for datagram sockets, and it will trigger \a on_data_recvfrom()
+ * callback instead.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_start_recvfrom (pj_ssl_sock_t *ssock,
+						pj_pool_t *pool,
+						unsigned buff_size,
+						pj_uint32_t flags)
+{
+    PJ_UNUSED_ARG(ssock);
+    PJ_UNUSED_ARG(pool);
+    PJ_UNUSED_ARG(buff_size);
+    PJ_UNUSED_ARG(flags);
+
+    return PJ_ENOTSUP;
+}
+
+
+/*
+ * Same as #pj_ssl_sock_start_recvfrom() except that the recvfrom() 
+ * operation takes the buffer from the argument rather than creating
+ * new ones.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_start_recvfrom2 (pj_ssl_sock_t *ssock,
+						 pj_pool_t *pool,
+						 unsigned buff_size,
+						 void *readbuf[],
+						 pj_uint32_t flags)
+{
+    PJ_UNUSED_ARG(ssock);
+    PJ_UNUSED_ARG(pool);
+    PJ_UNUSED_ARG(buff_size);
+    PJ_UNUSED_ARG(readbuf);
+    PJ_UNUSED_ARG(flags);
+
+    return PJ_ENOTSUP;
+}
+
+/* Write plain data to SSL and flush write BIO. Note that accessing
+ * write BIO must be serialized, so a call to this function must be
+ * protected by write mutex of SSL socket.
+ */
+static pj_status_t ssl_write(pj_ssl_sock_t *ssock, 
+			     pj_ioqueue_op_key_t *send_key,
+			     const void *data,
+			     pj_ssize_t size,
+			     unsigned flags)
+{
+    pj_status_t status;
+    int nwritten;
+
+    /* Write the plain data to SSL, after SSL encrypts it, write BIO will
+     * contain the secured data to be sent via socket. Note that re-
+     * negotitation may be on progress, so sending data should be delayed
+     * until re-negotiation is completed.
+     */
+    nwritten = SSL_write(ssock->ossl_ssl, data, size);
+    
+    if (nwritten == size) {
+	/* All data written, flush write BIO to network socket */
+	status = flush_write_bio(ssock, send_key, size, flags);
+    } else if (nwritten <= 0) {
+	/* SSL failed to process the data, it may just that re-negotiation
+	 * is on progress.
+	 */
+	int err;
+	err = SSL_get_error(ssock->ossl_ssl, nwritten);
+	if (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_NONE) {
+	    /* Re-negotiation is on progress, flush re-negotiation data */
+	    status = flush_write_bio(ssock, &ssock->handshake_op_key, 0, 0);
+	    if (status == PJ_SUCCESS || status == PJ_EPENDING)
+		status = PJ_EBUSY;
+	} else {
+	    /* Some problem occured */
+	    ssl_report_error(THIS_FILE, 4, PJ_SUCCESS, "SSL_write()");
+	    status = PJ_ECANCELLED;
+	}
+    } else {
+	/* nwritten < *size, shouldn't happen, unless write BIO cannot hold 
+	 * the whole secured data, perhaps because of insufficient memory.
+	 */
+	status = PJ_ENOMEM;
+    }
+
+    return status;
+}
+
+/* Flush delayed data sending in the write pending list. Note that accessing
+ * write pending list must be serialized, so a call to this function must be
+ * protected by write mutex of SSL socket.
+ */
+static pj_status_t flush_delayed_send(pj_ssl_sock_t *ssock)
+{
+    while (!pj_list_empty(&ssock->write_pending)) {
+        write_pending_t *wp;
+	pj_status_t status;
+
+	wp = ssock->write_pending.next;
+
+	status = ssl_write(ssock, &wp->data.key, wp->data.data.ptr, 
+			   wp->data.plain_data_len, wp->data.flags);
+	if (status != PJ_SUCCESS)
+	    return status;
+
+	pj_list_erase(wp);
+	pj_list_push_back(&ssock->write_pending_empty, wp);
+    }
+
+    return PJ_SUCCESS;
+}
+
+/* Sending is delayed, push back the sending data into pending list. Note that
+ * accessing write pending list must be serialized, so a call to this function
+ * must be protected by write mutex of SSL socket.
+ */
+static pj_status_t delay_send (pj_ssl_sock_t *ssock,
+			       pj_ioqueue_op_key_t *send_key,
+			       const void *data,
+			       pj_ssize_t size,
+			       unsigned flags)
+{
+    write_pending_t *wp;
+
+    /* Init write pending instance */
+    if (!pj_list_empty(&ssock->write_pending_empty)) {
+	wp = ssock->write_pending_empty.next;
+	pj_list_erase(wp);
+    } else {
+	wp = PJ_POOL_ZALLOC_T(ssock->pool, write_pending_t);
+    }
+
+    wp->data.app_key = send_key;
+    wp->data.plain_data_len = size;
+    wp->data.data.ptr = data;
+    wp->data.flags = flags;
+
+    pj_list_push_back(&ssock->write_pending, wp);
+
+    /* Must return PJ_EPENDING */
+    return PJ_EPENDING;
+}
+
+/**
+ * Send data using the socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_send (pj_ssl_sock_t *ssock,
+				      pj_ioqueue_op_key_t *send_key,
+				      const void *data,
+				      pj_ssize_t *size,
+				      unsigned flags)
+{
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(ssock && data && size && (*size>0), PJ_EINVAL);
+    PJ_ASSERT_RETURN(ssock->ssl_state==SSL_STATE_ESTABLISHED, PJ_EINVALIDOP);
+
+    pj_lock_acquire(ssock->write_mutex);
+
+    /* Flush delayed send first. Sending data might be delayed when 
+     * re-negotiation is on-progress.
+     */
+    status = flush_delayed_send(ssock);
+    if (status == PJ_EBUSY) {
+	/* Re-negotiation is on progress, delay sending */
+	status = delay_send(ssock, send_key, data, *size, flags);
+	goto on_return;
+    } else if (status != PJ_SUCCESS) {
+	goto on_return;
+    }
+
+    /* Write data to SSL */
+    status = ssl_write(ssock, send_key, data, *size, flags);
+    if (status == PJ_EBUSY) {
+	/* Re-negotiation is on progress, delay sending */
+	status = delay_send(ssock, send_key, data, *size, flags);
+    }
+
+on_return:
+    pj_lock_release(ssock->write_mutex);
+    return status;
+}
+
+
+/**
+ * Send datagram using the socket.
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_sendto (pj_ssl_sock_t *ssock,
+					pj_ioqueue_op_key_t *send_key,
+					const void *data,
+					pj_ssize_t *size,
+					unsigned flags,
+					const pj_sockaddr_t *addr,
+					int addr_len)
+{
+    PJ_UNUSED_ARG(ssock);
+    PJ_UNUSED_ARG(send_key);
+    PJ_UNUSED_ARG(data);
+    PJ_UNUSED_ARG(size);
+    PJ_UNUSED_ARG(flags);
+    PJ_UNUSED_ARG(addr);
+    PJ_UNUSED_ARG(addr_len);
+
+    return PJ_ENOTSUP;
+}
+
+
+/**
+ * Starts asynchronous socket accept() operations on this secure socket. 
+ */
+PJ_DEF(pj_status_t) pj_ssl_sock_start_accept (pj_ssl_sock_t *ssock,
+					      pj_pool_t *pool,
+					      const pj_sockaddr_t *localaddr,
+					      int addr_len)
+{
+    pj_activesock_cb asock_cb;
+    pj_activesock_cfg asock_cfg;
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(ssock && pool && localaddr && addr_len, PJ_EINVAL);
+
+    /* Create socket */
+    status = pj_sock_socket(ssock->param.sock_af, ssock->param.sock_type, 0, 
+			    &ssock->sock);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Bind socket */
+    status = pj_sock_bind(ssock->sock, localaddr, addr_len);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Start listening to the address */
+    status = pj_sock_listen(ssock->sock, PJ_SOMAXCONN);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Create active socket */
+    pj_activesock_cfg_default(&asock_cfg);
+    asock_cfg.async_cnt = ssock->param.async_cnt;
+    asock_cfg.concurrency = ssock->param.concurrency;
+    asock_cfg.whole_data = PJ_TRUE;
+
+    pj_bzero(&asock_cb, sizeof(asock_cb));
+    asock_cb.on_accept_complete = asock_on_accept_complete;
+
+    status = pj_activesock_create(pool,
+				  ssock->sock, 
+				  ssock->param.sock_type,
+				  &asock_cfg,
+				  ssock->param.ioqueue, 
+				  &asock_cb,
+				  ssock,
+				  &ssock->asock);
+
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Start accepting */
+    status = pj_activesock_start_accept(ssock->asock, pool);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Update local address */
+    ssock->addr_len = addr_len;
+    status = pj_sock_getsockname(ssock->sock, &ssock->local_addr, 
+				 &ssock->addr_len);
+    if (status != PJ_SUCCESS)
+	pj_sockaddr_cp(&ssock->local_addr, localaddr);
+
+    ssock->is_server = PJ_TRUE;
+
+    return PJ_SUCCESS;
+
+on_error:
+    reset_ssl_sock_state(ssock);
+    return status;
+}
+
+
+/**
+ * Starts asynchronous socket connect() operation.
+ */
+PJ_DECL(pj_status_t) pj_ssl_sock_start_connect(pj_ssl_sock_t *ssock,
+					       pj_pool_t *pool,
+					       const pj_sockaddr_t *localaddr,
+					       const pj_sockaddr_t *remaddr,
+					       int addr_len)
+{
+    pj_activesock_cb asock_cb;
+    pj_activesock_cfg asock_cfg;
+    pj_status_t status;
+
+    PJ_ASSERT_RETURN(ssock && pool && localaddr && remaddr && addr_len,
+		     PJ_EINVAL);
+
+    /* Create socket */
+    status = pj_sock_socket(ssock->param.sock_af, ssock->param.sock_type, 0, 
+			    &ssock->sock);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Bind socket */
+    status = pj_sock_bind(ssock->sock, localaddr, addr_len);
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    /* Create active socket */
+    pj_activesock_cfg_default(&asock_cfg);
+    asock_cfg.async_cnt = ssock->param.async_cnt;
+    asock_cfg.concurrency = ssock->param.concurrency;
+    asock_cfg.whole_data = PJ_TRUE;
+
+    pj_bzero(&asock_cb, sizeof(asock_cb));
+    asock_cb.on_connect_complete = asock_on_connect_complete;
+    asock_cb.on_data_read = asock_on_data_read;
+    asock_cb.on_data_sent = asock_on_data_sent;
+
+    status = pj_activesock_create(pool,
+				  ssock->sock, 
+				  ssock->param.sock_type,
+				  &asock_cfg,
+				  ssock->param.ioqueue, 
+				  &asock_cb,
+				  ssock,
+				  &ssock->asock);
+
+    if (status != PJ_SUCCESS)
+	goto on_error;
+
+    status = pj_activesock_start_connect(ssock->asock, pool, remaddr,
+					 addr_len);
+
+    if (status == PJ_SUCCESS)
+	asock_on_connect_complete(ssock->asock, PJ_SUCCESS);
+    else if (status != PJ_EPENDING)
+	goto on_error;
+
+    /* Update local address */
+    ssock->addr_len = addr_len;
+    status = pj_sock_getsockname(ssock->sock, &ssock->local_addr,
+				 &ssock->addr_len);
+    if (status != PJ_SUCCESS)
+	pj_sockaddr_cp(&ssock->local_addr, localaddr);
+
+    /* Set remote address */
+    pj_sockaddr_cp(&ssock->rem_addr, remaddr);
+
+    /* Update SSL state */
+    ssock->is_server = PJ_FALSE;
+
+    return PJ_EPENDING;
+
+on_error:
+    reset_ssl_sock_state(ssock);
+    return status;
+}
+
+
+//#endif  /* PJ_HAS_SSL_SOCK */
+