Import pjproject-2.0.1

1 files changed, 1576 insertions, 0 deletions

diff --git a/pjmedia/src/pjmedia/sdp.c b/pjmedia/src/pjmedia/sdp.c
new file mode 100644
index 0000000..e54bfcf
--- /dev/null
+++ b/pjmedia/src/pjmedia/sdp.c
@@ -0,0 +1,1576 @@
+/* $Id: sdp.c 3945 2012-01-27 09:12:59Z nanang $ */
+/* 
+ * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
+ * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
+ *
+ * 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 <pjmedia/sdp.h>
+#include <pjmedia/errno.h>
+#include <pjlib-util/scanner.h>
+#include <pj/array.h>
+#include <pj/except.h>
+#include <pj/log.h>
+#include <pj/os.h>
+#include <pj/string.h>
+#include <pj/pool.h>
+#include <pj/assert.h>
+#include <pj/ctype.h>
+
+
+enum {
+    SKIP_WS = 0,
+    SYNTAX_ERROR = 1,
+};
+// New token definition from RFC 4566 (SDP)
+#define TOKEN		"!#$%&'*+-.^_`{|}~"
+//#define TOKEN		"-.!%*_=`'~"
+//#define TOKEN		"'`-./:?\"#$&*;=@[]^_`{|}+~!"
+#define NTP_OFFSET	((pj_uint32_t)2208988800)
+#define THIS_FILE	"sdp.c"
+
+typedef struct parse_context
+{ 
+    pj_status_t last_error;
+} parse_context;
+
+
+/*
+ * Prototypes for line parser.
+ */
+static void parse_version(pj_scanner *scanner, parse_context *ctx);
+static void parse_origin(pj_scanner *scanner, pjmedia_sdp_session *ses,
+			 parse_context *ctx);
+static void parse_time(pj_scanner *scanner, pjmedia_sdp_session *ses,
+		       parse_context *ctx);
+static void parse_generic_line(pj_scanner *scanner, pj_str_t *str,
+			       parse_context *ctx);
+static void parse_connection_info(pj_scanner *scanner, pjmedia_sdp_conn *conn,
+				  parse_context *ctx);
+static void parse_bandwidth_info(pj_scanner *scanner, pjmedia_sdp_bandw *bandw,
+				  parse_context *ctx);
+static pjmedia_sdp_attr *parse_attr(pj_pool_t *pool, pj_scanner *scanner,
+				    parse_context *ctx);
+static void parse_media(pj_scanner *scanner, pjmedia_sdp_media *med,
+			parse_context *ctx);
+static void on_scanner_error(pj_scanner *scanner);
+
+/*
+ * Scanner character specification.
+ */
+static int is_initialized;
+static pj_cis_buf_t cis_buf;
+static pj_cis_t cs_digit, cs_token;
+
+static void init_sdp_parser(void)
+{
+    if (is_initialized != 0)
+	return;
+
+    pj_enter_critical_section();
+
+    if (is_initialized != 0) {
+	pj_leave_critical_section();
+	return;
+    }
+    
+    pj_cis_buf_init(&cis_buf);
+
+    pj_cis_init(&cis_buf, &cs_token);
+    pj_cis_add_alpha(&cs_token);
+    pj_cis_add_num(&cs_token);
+    pj_cis_add_str(&cs_token, TOKEN);
+
+    pj_cis_init(&cis_buf, &cs_digit);
+    pj_cis_add_num(&cs_digit);
+
+    is_initialized = 1;
+    pj_leave_critical_section();
+}
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_attr_create( pj_pool_t *pool,
+						   const char *name,
+						   const pj_str_t *value)
+{
+    pjmedia_sdp_attr *attr;
+
+    PJ_ASSERT_RETURN(pool && name, NULL);
+
+    attr = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_attr);
+    pj_strdup2(pool, &attr->name, name);
+
+    if (value)
+	pj_strdup_with_null(pool, &attr->value, value);
+    else {
+	attr->value.ptr = NULL;
+	attr->value.slen = 0;
+    }
+
+    return attr;
+}
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_attr_clone(pj_pool_t *pool, 
+						 const pjmedia_sdp_attr *rhs)
+{
+    pjmedia_sdp_attr *attr;
+    
+    PJ_ASSERT_RETURN(pool && rhs, NULL);
+
+    attr = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_attr);
+
+    pj_strdup(pool, &attr->name, &rhs->name);
+    pj_strdup_with_null(pool, &attr->value, &rhs->value);
+
+    return attr;
+}
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_attr_find (unsigned count, 
+				       pjmedia_sdp_attr *const attr_array[],
+				       const pj_str_t *name,
+				       const pj_str_t *c_fmt)
+{
+    unsigned i;
+    unsigned c_pt = 0xFFFF;
+
+    if (c_fmt)
+	c_pt = pj_strtoul(c_fmt);
+
+    for (i=0; i<count; ++i) {
+	if (pj_strcmp(&attr_array[i]->name, name) == 0) {
+	    const pjmedia_sdp_attr *a = attr_array[i];
+	    if (c_fmt) {
+		unsigned pt = (unsigned) pj_strtoul2(&a->value, NULL, 10);
+		if (pt == c_pt) {
+		    return (pjmedia_sdp_attr*)a;
+		}
+	    } else 
+		return (pjmedia_sdp_attr*)a;
+	}
+    }
+    return NULL;
+}
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_attr_find2(unsigned count, 
+				       pjmedia_sdp_attr *const attr_array[],
+				       const char *c_name,
+				       const pj_str_t *c_fmt)
+{
+    pj_str_t name;
+
+    name.ptr = (char*)c_name;
+    name.slen = pj_ansi_strlen(c_name);
+
+    return pjmedia_sdp_attr_find(count, attr_array, &name, c_fmt);
+}
+
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_add(unsigned *count,
+					 pjmedia_sdp_attr *attr_array[],
+					 pjmedia_sdp_attr *attr)
+{
+    PJ_ASSERT_RETURN(count && attr_array && attr, PJ_EINVAL);
+    PJ_ASSERT_RETURN(*count < PJMEDIA_MAX_SDP_ATTR, PJ_ETOOMANY);
+
+    attr_array[*count] = attr;
+    (*count)++;
+
+    return PJ_SUCCESS;
+}
+
+
+PJ_DEF(unsigned) pjmedia_sdp_attr_remove_all(unsigned *count,
+					     pjmedia_sdp_attr *attr_array[],
+					     const char *name)
+{
+    unsigned i, removed = 0;
+    pj_str_t attr_name;
+
+    PJ_ASSERT_RETURN(count && attr_array && name, PJ_EINVAL);
+
+    attr_name.ptr = (char*)name;
+    attr_name.slen = pj_ansi_strlen(name);
+
+    for (i=0; i<*count; ) {
+	if (pj_strcmp(&attr_array[i]->name, &attr_name)==0) {
+	    pj_array_erase(attr_array, sizeof(pjmedia_sdp_attr*),
+			   *count, i);
+	    --(*count);
+	    ++removed;
+	} else {
+	    ++i;
+	}   
+    }
+
+    return removed;
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_remove( unsigned *count,
+					     pjmedia_sdp_attr *attr_array[],
+					     pjmedia_sdp_attr *attr )
+{
+    unsigned i, removed=0;
+
+    PJ_ASSERT_RETURN(count && attr_array && attr, PJ_EINVAL);
+
+    for (i=0; i<*count; ) {
+	if (attr_array[i] == attr) {
+	    pj_array_erase(attr_array, sizeof(pjmedia_sdp_attr*),
+			   *count, i);
+	    --(*count);
+	    ++removed;
+	} else {
+	    ++i;
+	}
+    }
+
+    return removed ? PJ_SUCCESS : PJ_ENOTFOUND;
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_get_rtpmap( const pjmedia_sdp_attr *attr,
+						 pjmedia_sdp_rtpmap *rtpmap)
+{
+    pj_scanner scanner;
+    pj_str_t token;
+    pj_status_t status = -1;
+    char term = 0;
+    PJ_USE_EXCEPTION;
+
+    PJ_ASSERT_RETURN(pj_strcmp2(&attr->name, "rtpmap")==0, PJ_EINVALIDOP);
+
+    PJ_ASSERT_RETURN(attr->value.slen != 0, PJMEDIA_SDP_EINATTR);
+
+    init_sdp_parser();
+
+    /* Check if input is null terminated, and null terminate if
+     * necessary. Unfortunately this may crash the application if
+     * attribute was allocated from a read-only memory location.
+     * But this shouldn't happen as attribute's value normally is
+     * null terminated.
+     */
+    if (attr->value.ptr[attr->value.slen] != 0 &&
+	attr->value.ptr[attr->value.slen] != '\r' &&
+	attr->value.ptr[attr->value.slen] != '\n')
+    {
+	pj_assert(!"Shouldn't happen");
+	term = attr->value.ptr[attr->value.slen];
+	attr->value.ptr[attr->value.slen] = '\0';
+    }
+
+    pj_scan_init(&scanner, (char*)attr->value.ptr, attr->value.slen,
+		 PJ_SCAN_AUTOSKIP_WS, &on_scanner_error);
+
+    /* rtpmap sample:
+     *	a=rtpmap:98 L16/16000/2.
+     */
+
+    /* Init */
+    rtpmap->pt.slen = rtpmap->param.slen = rtpmap->enc_name.slen = 0;
+    rtpmap->clock_rate = 0;
+
+    /* Parse */
+    PJ_TRY {
+
+	/* Get payload type. */
+	pj_scan_get(&scanner, &cs_token, &rtpmap->pt);
+
+
+	/* Get encoding name. */
+	pj_scan_get(&scanner, &cs_token, &rtpmap->enc_name);
+
+	/* Expecting '/' after encoding name. */
+	if (pj_scan_get_char(&scanner) != '/') {
+	    status = PJMEDIA_SDP_EINRTPMAP;
+	    goto on_return;
+	}
+
+
+	/* Get the clock rate. */
+	pj_scan_get(&scanner, &cs_digit, &token);
+	rtpmap->clock_rate = pj_strtoul(&token);
+
+	/* Expecting either '/' or EOF */
+	if (*scanner.curptr == '/') {
+	    pj_scan_get_char(&scanner);
+	    rtpmap->param.ptr = scanner.curptr;
+	    rtpmap->param.slen = scanner.end - scanner.curptr;
+	} else {
+	    rtpmap->param.slen = 0;
+	}
+
+	status = PJ_SUCCESS;
+    }
+    PJ_CATCH_ANY {
+	status = PJMEDIA_SDP_EINRTPMAP;
+    }
+    PJ_END;
+
+
+on_return:
+    pj_scan_fini(&scanner);
+    if (term) {
+	attr->value.ptr[attr->value.slen] = term;
+    }
+    return status;
+}
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_get_fmtp( const pjmedia_sdp_attr *attr,
+					       pjmedia_sdp_fmtp *fmtp)
+{
+    const char *p = attr->value.ptr;
+    const char *end = attr->value.ptr + attr->value.slen;
+    pj_str_t token;
+
+    PJ_ASSERT_RETURN(pj_strcmp2(&attr->name, "fmtp")==0, PJ_EINVALIDOP);
+
+    /* fmtp BNF:
+     *	a=fmtp:<format> <format specific parameter>
+     */
+
+    /* Get format. */
+    token.ptr = (char*)p;
+    while (pj_isdigit(*p) && p!=end)
+	++p;
+    token.slen = p - token.ptr;
+    if (token.slen == 0)
+	return PJMEDIA_SDP_EINFMTP;
+
+    fmtp->fmt = token;
+
+    /* Expecting space after format. */
+    if (*p != ' ') return PJMEDIA_SDP_EINFMTP;
+
+    /* Get space. */
+    ++p;
+
+    /* Set the remaining string as fmtp format parameter. */
+    fmtp->fmt_param.ptr = (char*)p;
+    fmtp->fmt_param.slen = end - p;
+
+    return PJ_SUCCESS;
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_get_rtcp(const pjmedia_sdp_attr *attr,
+					      pjmedia_sdp_rtcp_attr *rtcp)
+{
+    pj_scanner scanner;
+    pj_str_t token;
+    pj_status_t status = -1;
+    PJ_USE_EXCEPTION;
+
+    PJ_ASSERT_RETURN(pj_strcmp2(&attr->name, "rtcp")==0, PJ_EINVALIDOP);
+
+    init_sdp_parser();
+
+    /* fmtp BNF:
+     *	a=rtcp:<port> [nettype addrtype address]
+     */
+
+    pj_scan_init(&scanner, (char*)attr->value.ptr, attr->value.slen,
+		 PJ_SCAN_AUTOSKIP_WS, &on_scanner_error);
+
+    /* Init */
+    rtcp->net_type.slen = rtcp->addr_type.slen = rtcp->addr.slen = 0;
+
+    /* Parse */
+    PJ_TRY {
+
+	/* Get the port */
+	pj_scan_get(&scanner, &cs_token, &token);
+	rtcp->port = pj_strtoul(&token);
+
+	/* Have address? */
+	if (!pj_scan_is_eof(&scanner)) {
+
+	    /* Get network type */
+	    pj_scan_get(&scanner, &cs_token, &rtcp->net_type);
+
+	    /* Get address type */
+	    pj_scan_get(&scanner, &cs_token, &rtcp->addr_type);
+
+	    /* Get the address */
+	    pj_scan_get(&scanner, &cs_token, &rtcp->addr);
+
+	}
+
+	status = PJ_SUCCESS;
+
+    }
+    PJ_CATCH_ANY {
+	status = PJMEDIA_SDP_EINRTCP;
+    }
+    PJ_END;
+
+    pj_scan_fini(&scanner);
+    return status;
+}
+
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_attr_create_rtcp(pj_pool_t *pool,
+						       const pj_sockaddr *a)
+{
+    enum {
+	ATTR_LEN = PJ_INET6_ADDRSTRLEN+16
+    };
+    pjmedia_sdp_attr *attr;
+
+    attr = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_attr);
+    attr->name = pj_str("rtcp");
+    attr->value.ptr = (char*) pj_pool_alloc(pool, ATTR_LEN);
+    if (a->addr.sa_family == pj_AF_INET()) {
+	attr->value.slen = 
+	    pj_ansi_snprintf(attr->value.ptr, ATTR_LEN,
+			    "%u IN IP4 %s",
+			    pj_ntohs(a->ipv4.sin_port),
+			    pj_inet_ntoa(a->ipv4.sin_addr));
+    } else if (a->addr.sa_family == pj_AF_INET6()) {
+	char tmp_addr[PJ_INET6_ADDRSTRLEN];
+	attr->value.slen = 
+	    pj_ansi_snprintf(attr->value.ptr, ATTR_LEN,
+			    "%u IN IP6 %s",
+			    pj_sockaddr_get_port(a),
+			    pj_sockaddr_print(a, tmp_addr, 
+					      sizeof(tmp_addr), 0));
+
+    } else {
+	pj_assert(!"Unsupported address family");
+	return NULL;
+    }
+
+    return attr;
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_attr_to_rtpmap(pj_pool_t *pool,
+					       const pjmedia_sdp_attr *attr,
+					       pjmedia_sdp_rtpmap **p_rtpmap)
+{
+    PJ_ASSERT_RETURN(pool && attr && p_rtpmap, PJ_EINVAL);
+
+    *p_rtpmap = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_rtpmap);
+    PJ_ASSERT_RETURN(*p_rtpmap, PJ_ENOMEM);
+
+    return pjmedia_sdp_attr_get_rtpmap(attr, *p_rtpmap);
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_rtpmap_to_attr(pj_pool_t *pool,
+					       const pjmedia_sdp_rtpmap *rtpmap,
+					       pjmedia_sdp_attr **p_attr)
+{
+    pjmedia_sdp_attr *attr;
+    char tempbuf[128];
+    int len;
+
+    /* Check arguments. */
+    PJ_ASSERT_RETURN(pool && rtpmap && p_attr, PJ_EINVAL);
+
+    /* Check that mandatory attributes are specified. */
+    PJ_ASSERT_RETURN(rtpmap->enc_name.slen && rtpmap->clock_rate,
+		     PJMEDIA_SDP_EINRTPMAP);
+
+
+    attr = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_attr);
+    PJ_ASSERT_RETURN(attr != NULL, PJ_ENOMEM);
+
+    attr->name.ptr = "rtpmap";
+    attr->name.slen = 6;
+
+    /* Format: ":pt enc_name/clock_rate[/param]" */
+    len = pj_ansi_snprintf(tempbuf, sizeof(tempbuf), 
+			   "%.*s %.*s/%u%s%.*s",
+			   (int)rtpmap->pt.slen,
+			   rtpmap->pt.ptr,
+			   (int)rtpmap->enc_name.slen,
+			   rtpmap->enc_name.ptr,
+			   rtpmap->clock_rate,
+			   (rtpmap->param.slen ? "/" : ""),
+			   (int)rtpmap->param.slen,
+			   rtpmap->param.ptr);
+
+    if (len < 1 || len > (int)sizeof(tempbuf))
+	return PJMEDIA_SDP_ERTPMAPTOOLONG;
+
+    attr->value.slen = len;
+    attr->value.ptr = (char*) pj_pool_alloc(pool, attr->value.slen+1);
+    pj_memcpy(attr->value.ptr, tempbuf, attr->value.slen+1);
+
+    *p_attr = attr;
+    return PJ_SUCCESS;
+}
+
+
+static int print_connection_info( pjmedia_sdp_conn *c, char *buf, int len)
+{
+    int printed;
+
+    printed = pj_ansi_snprintf(buf, len, "c=%.*s %.*s %.*s\r\n",
+			       (int)c->net_type.slen,
+			       c->net_type.ptr,
+			       (int)c->addr_type.slen,
+			       c->addr_type.ptr,
+			       (int)c->addr.slen,
+			       c->addr.ptr);
+    if (printed < 1 || printed > len)
+	return -1;
+
+    return printed;
+}
+
+
+PJ_DEF(pjmedia_sdp_conn*) pjmedia_sdp_conn_clone (pj_pool_t *pool, 
+						  const pjmedia_sdp_conn *rhs)
+{
+    pjmedia_sdp_conn *c = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_conn);
+    if (!c) return NULL;
+
+    if (!pj_strdup (pool, &c->net_type, &rhs->net_type)) return NULL;
+    if (!pj_strdup (pool, &c->addr_type, &rhs->addr_type)) return NULL;
+    if (!pj_strdup (pool, &c->addr, &rhs->addr)) return NULL;
+
+    return c;
+}
+
+PJ_DEF(pjmedia_sdp_bandw*)
+pjmedia_sdp_bandw_clone (pj_pool_t *pool, 
+			 const pjmedia_sdp_bandw *rhs)
+{
+    pjmedia_sdp_bandw *b = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_bandw);
+    if (!b) return NULL;
+
+    if (!pj_strdup (pool, &b->modifier, &rhs->modifier)) return NULL;
+    b->value = rhs->value;
+
+    return b;
+}
+
+static pj_ssize_t print_bandw(const pjmedia_sdp_bandw *bandw,
+			      char *buf, pj_size_t len)
+{
+    char *p = buf;
+
+    if ((int)len < bandw->modifier.slen + 10 + 5)
+	return -1;
+
+    *p++ = 'b';
+    *p++ = '=';
+    pj_memcpy(p, bandw->modifier.ptr, bandw->modifier.slen);
+    p += bandw->modifier.slen;
+    *p++ = ':';
+    p += pj_utoa(bandw->value, p);
+
+    *p++ = '\r';
+    *p++ = '\n';
+    return p-buf;
+}
+
+static pj_ssize_t print_attr(const pjmedia_sdp_attr *attr, 
+			     char *buf, pj_size_t len)
+{
+    char *p = buf;
+
+    if ((int)len < attr->name.slen + attr->value.slen + 10)
+	return -1;
+
+    *p++ = 'a';
+    *p++ = '=';
+    pj_memcpy(p, attr->name.ptr, attr->name.slen);
+    p += attr->name.slen;
+    
+
+    if (attr->value.slen) {
+	*p++ = ':';
+	pj_memcpy(p, attr->value.ptr, attr->value.slen);
+	p += attr->value.slen;
+    }
+
+    *p++ = '\r';
+    *p++ = '\n';
+    return p-buf;
+}
+
+static int print_media_desc( pjmedia_sdp_media *m, char *buf, int len)
+{
+    char *p = buf;
+    char *end = buf+len;
+    unsigned i;
+    int printed;
+
+    /* check length for the "m=" line. */
+    if (len < m->desc.media.slen+m->desc.transport.slen+12+24) {
+	return -1;
+    }
+    *p++ = 'm';	    /* m= */
+    *p++ = '=';
+    pj_memcpy(p, m->desc.media.ptr, m->desc.media.slen);
+    p += m->desc.media.slen;
+    *p++ = ' ';
+    printed = pj_utoa(m->desc.port, p);
+    p += printed;
+    if (m->desc.port_count > 1) {
+	*p++ = '/';
+	printed = pj_utoa(m->desc.port_count, p);
+	p += printed;
+    }
+    *p++ = ' ';
+    pj_memcpy(p, m->desc.transport.ptr, m->desc.transport.slen);
+    p += m->desc.transport.slen;
+    for (i=0; i<m->desc.fmt_count; ++i) {
+	*p++ = ' ';
+	pj_memcpy(p, m->desc.fmt[i].ptr, m->desc.fmt[i].slen);
+	p += m->desc.fmt[i].slen;
+    }
+    *p++ = '\r';
+    *p++ = '\n';
+
+    /* print connection info, if present. */
+    if (m->conn) {
+	printed = print_connection_info(m->conn, p, end-p);
+	if (printed < 0) {
+	    return -1;
+	}
+	p += printed;
+    }
+    
+    /* print optional bandwidth info. */
+    for (i=0; i<m->bandw_count; ++i) {
+	printed = print_bandw(m->bandw[i], p, end-p);
+	if (printed < 0) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    /* print attributes. */
+    for (i=0; i<m->attr_count; ++i) {
+	printed = print_attr(m->attr[i], p, end-p);
+	if (printed < 0) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    return p-buf;
+}
+
+PJ_DEF(pjmedia_sdp_media*) pjmedia_sdp_media_clone(
+						 pj_pool_t *pool, 
+						 const pjmedia_sdp_media *rhs)
+{
+    unsigned int i;
+    pjmedia_sdp_media *m = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_media);
+    PJ_ASSERT_RETURN(m != NULL, NULL);
+
+    pj_strdup (pool, &m->desc.media, &rhs->desc.media);
+    m->desc.port = rhs->desc.port;
+    m->desc.port_count = rhs->desc.port_count;
+    pj_strdup (pool, &m->desc.transport, &rhs->desc.transport);
+    m->desc.fmt_count = rhs->desc.fmt_count;
+    for (i=0; i<rhs->desc.fmt_count; ++i)
+	pj_strdup(pool, &m->desc.fmt[i], &rhs->desc.fmt[i]);
+
+    if (rhs->conn) {
+	m->conn = pjmedia_sdp_conn_clone (pool, rhs->conn);
+	PJ_ASSERT_RETURN(m->conn != NULL, NULL);
+    } else {
+	m->conn = NULL;
+    }
+
+    m->bandw_count = rhs->bandw_count;
+    for (i=0; i < rhs->bandw_count; ++i) {
+	m->bandw[i] = pjmedia_sdp_bandw_clone (pool, rhs->bandw[i]);
+	PJ_ASSERT_RETURN(m->bandw[i] != NULL, NULL);
+    }
+
+    m->attr_count = rhs->attr_count;
+    for (i=0; i < rhs->attr_count; ++i) {
+	m->attr[i] = pjmedia_sdp_attr_clone (pool, rhs->attr[i]);
+	PJ_ASSERT_RETURN(m->attr[i] != NULL, NULL);
+    }
+
+    return m;
+}
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_media_find_attr(
+				const pjmedia_sdp_media *m,
+				const pj_str_t *name, const pj_str_t *fmt)
+{
+    PJ_ASSERT_RETURN(m && name, NULL);
+    return pjmedia_sdp_attr_find(m->attr_count, m->attr, name, fmt);
+}
+
+
+
+PJ_DEF(pjmedia_sdp_attr*) pjmedia_sdp_media_find_attr2(
+				const pjmedia_sdp_media *m,
+				const char *name, const pj_str_t *fmt)
+{
+    PJ_ASSERT_RETURN(m && name, NULL);
+    return pjmedia_sdp_attr_find2(m->attr_count, m->attr, name, fmt);
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_media_add_attr( pjmedia_sdp_media *m,
+						pjmedia_sdp_attr *attr)
+{
+    return pjmedia_sdp_attr_add(&m->attr_count, m->attr, attr);
+}
+
+PJ_DEF(pj_status_t) pjmedia_sdp_session_add_attr(pjmedia_sdp_session *s,
+						 pjmedia_sdp_attr *attr)
+{
+    return pjmedia_sdp_attr_add(&s->attr_count, s->attr, attr);
+}
+
+PJ_DEF(unsigned) pjmedia_sdp_media_remove_all_attr(pjmedia_sdp_media *m,
+						   const char *name)
+{
+    return pjmedia_sdp_attr_remove_all(&m->attr_count, m->attr, name);
+}
+
+PJ_DEF(pj_status_t) pjmedia_sdp_media_remove_attr(pjmedia_sdp_media *m,
+			      			  pjmedia_sdp_attr *attr)
+{
+    return pjmedia_sdp_attr_remove(&m->attr_count, m->attr, attr);
+}
+
+static int print_session(const pjmedia_sdp_session *ses, 
+			 char *buf, pj_ssize_t len)
+{
+    char *p = buf;
+    char *end = buf+len;
+    unsigned i;
+    int printed;
+
+    /* Check length for v= and o= lines. */
+    if (len < 5+ 
+	      2+ses->origin.user.slen+18+
+	      ses->origin.net_type.slen+ses->origin.addr.slen + 2)
+    {
+	return -1;
+    }
+
+    /* SDP version (v= line) */
+    pj_memcpy(p, "v=0\r\n", 5);
+    p += 5;
+
+    /* Owner (o=) line. */
+    *p++ = 'o';
+    *p++ = '=';
+    pj_memcpy(p, ses->origin.user.ptr, ses->origin.user.slen);
+    p += ses->origin.user.slen;
+    *p++ = ' ';
+    printed = pj_utoa(ses->origin.id, p);
+    p += printed;
+    *p++ = ' ';
+    printed = pj_utoa(ses->origin.version, p);
+    p += printed;
+    *p++ = ' ';
+    pj_memcpy(p, ses->origin.net_type.ptr, ses->origin.net_type.slen);
+    p += ses->origin.net_type.slen;
+    *p++ = ' ';
+    pj_memcpy(p, ses->origin.addr_type.ptr, ses->origin.addr_type.slen);
+    p += ses->origin.addr_type.slen;
+    *p++ = ' ';
+    pj_memcpy(p, ses->origin.addr.ptr, ses->origin.addr.slen);
+    p += ses->origin.addr.slen;
+    *p++ = '\r';
+    *p++ = '\n';
+
+    /* Session name (s=) line. */
+    if ((end-p)  < 8+ses->name.slen) {
+	return -1;
+    }
+    *p++ = 's';
+    *p++ = '=';
+    pj_memcpy(p, ses->name.ptr, ses->name.slen);
+    p += ses->name.slen;
+    *p++ = '\r';
+    *p++ = '\n';
+
+    /* Connection line (c=) if exist. */
+    if (ses->conn) {
+	printed = print_connection_info(ses->conn, p, end-p);
+	if (printed < 1) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    /* print optional bandwidth info. */
+    for (i=0; i<ses->bandw_count; ++i) {
+	printed = print_bandw(ses->bandw[i], p, end-p);
+	if (printed < 1) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    /* Time */
+    if ((end-p) < 24) {
+	return -1;
+    }
+    *p++ = 't';
+    *p++ = '=';
+    printed = pj_utoa(ses->time.start, p);
+    p += printed;
+    *p++ = ' ';
+    printed = pj_utoa(ses->time.stop, p);
+    p += printed;
+    *p++ = '\r';
+    *p++ = '\n';
+
+    /* Print all attribute (a=) lines. */
+    for (i=0; i<ses->attr_count; ++i) {
+	printed = print_attr(ses->attr[i], p, end-p);
+	if (printed < 0) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    /* Print media (m=) lines. */
+    for (i=0; i<ses->media_count; ++i) {
+	printed = print_media_desc(ses->media[i], p, end-p);
+	if (printed < 0) {
+	    return -1;
+	}
+	p += printed;
+    }
+
+    return p-buf;
+}
+
+/******************************************************************************
+ * PARSERS
+ */
+
+static void parse_version(pj_scanner *scanner, parse_context *ctx)
+{
+    ctx->last_error = PJMEDIA_SDP_EINVER;
+
+    /* check equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* check version is 0 */
+    if (*(scanner->curptr+2) != '0') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+}
+
+static void parse_origin(pj_scanner *scanner, pjmedia_sdp_session *ses,
+			 parse_context *ctx)
+{
+    pj_str_t str;
+
+    ctx->last_error = PJMEDIA_SDP_EINORIGIN;
+
+    /* check equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* o= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* username. */
+    pj_scan_get_until_ch(scanner, ' ', &ses->origin.user);
+    pj_scan_get_char(scanner);
+
+    /* id */
+    pj_scan_get_until_ch(scanner, ' ', &str);
+    ses->origin.id = pj_strtoul(&str);
+    pj_scan_get_char(scanner);
+
+    /* version */
+    pj_scan_get_until_ch(scanner, ' ', &str);
+    ses->origin.version = pj_strtoul(&str);
+    pj_scan_get_char(scanner);
+
+    /* network-type */
+    pj_scan_get_until_ch(scanner, ' ', &ses->origin.net_type);
+    pj_scan_get_char(scanner);
+
+    /* addr-type */
+    pj_scan_get_until_ch(scanner, ' ', &ses->origin.addr_type);
+    pj_scan_get_char(scanner);
+
+    /* address */
+    pj_scan_get_until_chr(scanner, " \t\r\n", &ses->origin.addr);
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+
+}
+
+static void parse_time(pj_scanner *scanner, pjmedia_sdp_session *ses,
+		       parse_context *ctx)
+{
+    pj_str_t str;
+
+    ctx->last_error = PJMEDIA_SDP_EINTIME;
+
+    /* check equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* t= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* start time */
+    pj_scan_get_until_ch(scanner, ' ', &str);
+    ses->time.start = pj_strtoul(&str);
+
+    pj_scan_get_char(scanner);
+
+    /* stop time */
+    pj_scan_get_until_chr(scanner, " \t\r\n", &str);
+    ses->time.stop = pj_strtoul(&str);
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+}
+
+static void parse_generic_line(pj_scanner *scanner, pj_str_t *str,
+			       parse_context *ctx)
+{
+    ctx->last_error = PJMEDIA_SDP_EINSDP;
+
+    /* check equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* x= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* get anything until newline (including whitespaces). */
+    pj_scan_get_until_chr(scanner, "\r\n", str);
+
+    /* newline. */
+    pj_scan_get_newline(scanner);
+}
+
+static void parse_connection_info(pj_scanner *scanner, pjmedia_sdp_conn *conn,
+				  parse_context *ctx)
+{
+    ctx->last_error = PJMEDIA_SDP_EINCONN;
+
+    /* c= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* network-type */
+    pj_scan_get_until_ch(scanner, ' ', &conn->net_type);
+    pj_scan_get_char(scanner);
+
+    /* addr-type */
+    pj_scan_get_until_ch(scanner, ' ', &conn->addr_type);
+    pj_scan_get_char(scanner);
+
+    /* address. */
+    pj_scan_get_until_chr(scanner, "/ \t\r\n", &conn->addr);
+    PJ_TODO(PARSE_SDP_CONN_ADDRESS_SUBFIELDS);
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+}
+
+static void parse_bandwidth_info(pj_scanner *scanner, pjmedia_sdp_bandw *bandw,
+				  parse_context *ctx)
+{
+    pj_str_t str;
+
+    ctx->last_error = PJMEDIA_SDP_EINBANDW;
+
+    /* b= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* modifier */
+    pj_scan_get_until_ch(scanner, ':', &bandw->modifier);
+    pj_scan_get_char(scanner);
+
+    /* value */
+    pj_scan_get_until_chr(scanner, " \t\r\n", &str);
+    bandw->value = pj_strtoul(&str);
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+}
+
+static void parse_media(pj_scanner *scanner, pjmedia_sdp_media *med,
+			parse_context *ctx)
+{
+    pj_str_t str;
+
+    ctx->last_error = PJMEDIA_SDP_EINMEDIA;
+
+    /* check the equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return;
+    }
+
+    /* m= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+
+    /* type */
+    pj_scan_get_until_ch(scanner, ' ', &med->desc.media);
+    pj_scan_get_char(scanner);
+
+    /* port */
+    pj_scan_get(scanner, &cs_token, &str);
+    med->desc.port = (unsigned short)pj_strtoul(&str);
+    if (*scanner->curptr == '/') {
+	/* port count */
+	pj_scan_get_char(scanner);
+	pj_scan_get(scanner, &cs_token, &str);
+	med->desc.port_count = pj_strtoul(&str);
+
+    } else {
+	med->desc.port_count = 0;
+    }
+
+    if (pj_scan_get_char(scanner) != ' ') {
+	PJ_THROW(SYNTAX_ERROR);
+    }
+
+    /* transport */
+    pj_scan_get_until_chr(scanner, " \t\r\n", &med->desc.transport);
+
+    /* format list */
+    med->desc.fmt_count = 0;
+    while (*scanner->curptr == ' ') {
+	pj_str_t fmt;
+
+	pj_scan_get_char(scanner);
+
+	/* Check again for the end of the line */
+	if ((*scanner->curptr == '\r') || (*scanner->curptr == '\n'))
+		break;
+
+	pj_scan_get(scanner, &cs_token, &fmt);
+	if (med->desc.fmt_count < PJMEDIA_MAX_SDP_FMT)
+	    med->desc.fmt[med->desc.fmt_count++] = fmt;
+	else
+	    PJ_PERROR(2,(THIS_FILE, PJ_ETOOMANY, 
+		         "Error adding SDP media format %.*s, "
+			 "format is ignored",
+			 (int)fmt.slen, fmt.ptr));
+    }
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+}
+
+static void on_scanner_error(pj_scanner *scanner)
+{
+    PJ_UNUSED_ARG(scanner);
+
+    PJ_THROW(SYNTAX_ERROR);
+}
+
+static pjmedia_sdp_attr *parse_attr( pj_pool_t *pool, pj_scanner *scanner,
+				    parse_context *ctx)
+{
+    pjmedia_sdp_attr *attr;
+
+    ctx->last_error = PJMEDIA_SDP_EINATTR;
+
+    attr = PJ_POOL_ALLOC_T(pool, pjmedia_sdp_attr);
+
+    /* check equal sign */
+    if (*(scanner->curptr+1) != '=') {
+	on_scanner_error(scanner);
+	return NULL;
+    }
+
+    /* skip a= */
+    pj_scan_advance_n(scanner, 2, SKIP_WS);
+    
+    /* get attr name. */
+    pj_scan_get(scanner, &cs_token, &attr->name);
+
+    if (*scanner->curptr && *scanner->curptr != '\r' && 
+	*scanner->curptr != '\n') 
+    {
+	/* skip ':' if present. */
+	if (*scanner->curptr == ':')
+	    pj_scan_get_char(scanner);
+
+	/* get value */
+	if (*scanner->curptr != '\r' && *scanner->curptr != '\n') {
+	    pj_scan_get_until_chr(scanner, "\r\n", &attr->value);
+	} else {
+	    attr->value.ptr = NULL;
+	    attr->value.slen = 0;
+	}
+
+    } else {
+	attr->value.ptr = NULL;
+	attr->value.slen = 0;
+    }
+
+    /* We've got what we're looking for, skip anything until newline */
+    pj_scan_skip_line(scanner);
+
+    return attr;
+}
+
+
+/*
+ * Apply direction attribute in session to all media.
+ */
+static void apply_media_direction(pjmedia_sdp_session *sdp)
+{
+    pjmedia_sdp_attr *dir_attr = NULL;
+    unsigned i;
+
+    const pj_str_t inactive = { "inactive", 8 };
+    const pj_str_t sendonly = { "sendonly", 8 };
+    const pj_str_t recvonly = { "recvonly", 8 };
+    const pj_str_t sendrecv = { "sendrecv", 8 };
+
+    /* Find direction attribute in session, don't need to find default 
+     * direction "sendrecv".
+     */
+    for (i = 0; i < sdp->attr_count && !dir_attr; ++i) {
+	if (!pj_strcmp(&sdp->attr[i]->name, &sendonly) ||
+	    !pj_strcmp(&sdp->attr[i]->name, &recvonly) ||
+	    !pj_strcmp(&sdp->attr[i]->name, &inactive)) 
+	{
+	    dir_attr = sdp->attr[i];
+	}
+    }
+
+    /* Found the direction attribute */
+    if (dir_attr) {
+	/* Remove the direction attribute in session */
+	pjmedia_sdp_attr_remove(&sdp->attr_count, sdp->attr, dir_attr);
+
+	/* Apply the direction attribute to all media, but not overriding it
+	 * if media already has direction attribute.
+	 */
+	for (i = 0; i < sdp->media_count; ++i) {
+	    pjmedia_sdp_media *m;
+	    unsigned j;
+
+	    /* Find direction attribute in this media */
+	    m = sdp->media[i];
+	    for (j = 0; j < m->attr_count; ++j) {
+		if (!pj_strcmp(&m->attr[j]->name, &sendrecv) ||
+		    !pj_strcmp(&m->attr[j]->name, &sendonly) ||
+		    !pj_strcmp(&m->attr[j]->name, &recvonly) ||
+		    !pj_strcmp(&m->attr[j]->name, &inactive)) 
+		{
+		    break;
+		}
+	    }
+
+	    /* Not found, apply direction attribute from session */
+	    if (j == m->attr_count)
+		pjmedia_sdp_media_add_attr(m, dir_attr);
+	}
+    }
+}
+
+
+/*
+ * Parse SDP message.
+ */
+PJ_DEF(pj_status_t) pjmedia_sdp_parse( pj_pool_t *pool,
+				       char *buf, pj_size_t len, 
+				       pjmedia_sdp_session **p_sdp)
+{
+    pj_scanner scanner;
+    pjmedia_sdp_session *session;
+    pjmedia_sdp_media *media = NULL;
+    pjmedia_sdp_attr *attr;
+    pjmedia_sdp_conn *conn;
+    pjmedia_sdp_bandw *bandw;
+    pj_str_t dummy;
+    int cur_name = 254;
+    parse_context ctx;
+    PJ_USE_EXCEPTION;
+
+    ctx.last_error = PJ_SUCCESS;
+
+    init_sdp_parser();
+
+    pj_scan_init(&scanner, buf, len, 0, &on_scanner_error);
+    session = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_session);
+    PJ_ASSERT_RETURN(session != NULL, PJ_ENOMEM);
+
+    /* Ignore leading newlines */
+    while (*scanner.curptr=='\r' || *scanner.curptr=='\n')
+	pj_scan_get_char(&scanner);
+
+    PJ_TRY {
+	while (!pj_scan_is_eof(&scanner)) {
+		cur_name = *scanner.curptr;
+		switch (cur_name) {
+		case 'a':
+		    attr = parse_attr(pool, &scanner, &ctx);
+		    if (attr) {
+			if (media) {
+			    pjmedia_sdp_media_add_attr(media, attr);
+			} else {
+			    pjmedia_sdp_session_add_attr(session, attr);
+			}
+		    }
+		    break;
+		case 'o':
+		    parse_origin(&scanner, session, &ctx);
+		    break;
+		case 's':
+		    parse_generic_line(&scanner, &session->name, &ctx);
+		    break;
+		case 'c':
+		    conn = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_conn);
+		    parse_connection_info(&scanner, conn, &ctx);
+		    if (media) {
+			media->conn = conn;
+		    } else {
+			session->conn = conn;
+		    }
+		    break;
+		case 't':
+		    parse_time(&scanner, session, &ctx);
+		    break;
+		case 'm':
+		    media = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_media);
+		    parse_media(&scanner, media, &ctx);
+		    if (session->media_count < PJMEDIA_MAX_SDP_MEDIA)
+			session->media[ session->media_count++ ] = media;
+		    else
+			PJ_PERROR(2,(THIS_FILE, PJ_ETOOMANY,
+				     "Error adding media, media is ignored"));
+		    break;
+		case 'v':
+		    parse_version(&scanner, &ctx);
+		    break;
+		case 13:
+		case 10:
+		    pj_scan_get_char(&scanner);
+		    /* Allow empty newlines at the end of the message */
+		    while (!pj_scan_is_eof(&scanner)) {
+			if (*scanner.curptr != 13 && *scanner.curptr != 10) {
+			    ctx.last_error = PJMEDIA_SDP_EINSDP;
+			    on_scanner_error(&scanner);
+			}
+			pj_scan_get_char(&scanner);
+		    }
+		    break;
+		case 'b':
+		    bandw = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_bandw);
+		    parse_bandwidth_info(&scanner, bandw, &ctx);
+		    if (media) {
+			media->bandw[media->bandw_count++] = bandw;
+		    } else {
+			session->bandw[session->bandw_count++] = bandw;
+		    }
+		    break;
+		default:
+		    if (cur_name >= 'a' && cur_name <= 'z')
+			parse_generic_line(&scanner, &dummy, &ctx);
+		    else  {
+			ctx.last_error = PJMEDIA_SDP_EINSDP;
+			on_scanner_error(&scanner);
+		    }
+		    break;
+		}
+	}
+
+	ctx.last_error = PJ_SUCCESS;
+
+    }
+    PJ_CATCH_ANY {
+	
+	char errmsg[PJ_ERR_MSG_SIZE];
+	pj_strerror(ctx.last_error, errmsg, sizeof(errmsg));
+
+	PJ_LOG(4, (THIS_FILE, "Error parsing SDP in line %d col %d: %s",
+		   scanner.line, pj_scan_get_col(&scanner),
+		   errmsg));
+
+	session = NULL;
+
+	pj_assert(ctx.last_error != PJ_SUCCESS);
+    }
+    PJ_END;
+
+    pj_scan_fini(&scanner);
+
+    if (session)
+	apply_media_direction(session);
+
+    *p_sdp = session;
+    return ctx.last_error;
+}
+
+/*
+ * Print SDP description.
+ */
+PJ_DEF(int) pjmedia_sdp_print( const pjmedia_sdp_session *desc, 
+			       char *buf, pj_size_t size)
+{
+    return print_session(desc, buf, size);
+}
+
+
+/*
+ * Clone session
+ */
+PJ_DEF(pjmedia_sdp_session*) pjmedia_sdp_session_clone( pj_pool_t *pool,
+			   			const pjmedia_sdp_session *rhs)
+{
+    pjmedia_sdp_session *sess;
+    unsigned i;
+
+    PJ_ASSERT_RETURN(pool && rhs, NULL);
+
+    sess = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_session);
+    PJ_ASSERT_RETURN(sess != NULL, NULL);
+
+    /* Clone origin line. */
+    pj_strdup(pool, &sess->origin.user, &rhs->origin.user);
+    sess->origin.id = rhs->origin.id;
+    sess->origin.version = rhs->origin.version;
+    pj_strdup(pool, &sess->origin.net_type, &rhs->origin.net_type);
+    pj_strdup(pool, &sess->origin.addr_type, &rhs->origin.addr_type);
+    pj_strdup(pool, &sess->origin.addr, &rhs->origin.addr);
+
+    /* Clone subject line. */
+    pj_strdup(pool, &sess->name, &rhs->name);
+
+    /* Clone connection line */
+    if (rhs->conn) {
+	sess->conn = pjmedia_sdp_conn_clone(pool, rhs->conn);
+	PJ_ASSERT_RETURN(sess->conn != NULL, NULL);
+    }
+
+    /* Duplicate bandwidth info */
+    sess->bandw_count = rhs->bandw_count;
+    for (i=0; i<rhs->bandw_count; ++i) {
+	sess->bandw[i] = pjmedia_sdp_bandw_clone(pool, rhs->bandw[i]);
+    }
+
+    /* Clone time line. */
+    sess->time.start = rhs->time.start;
+    sess->time.stop = rhs->time.stop;
+
+    /* Duplicate session attributes. */
+    sess->attr_count = rhs->attr_count;
+    for (i=0; i<rhs->attr_count; ++i) {
+	sess->attr[i] = pjmedia_sdp_attr_clone(pool, rhs->attr[i]);
+    }
+
+    /* Duplicate media descriptors. */
+    sess->media_count = rhs->media_count;
+    for (i=0; i<rhs->media_count; ++i) {
+	sess->media[i] = pjmedia_sdp_media_clone(pool, rhs->media[i]);
+    }
+
+    return sess;
+}
+
+
+#define CHECK(exp,ret)	do {			\
+			    /*pj_assert(exp);*/	\
+			    if (!(exp))		\
+				return ret;	\
+			} while (0)
+
+/* Validate SDP connetion info. */
+static pj_status_t validate_sdp_conn(const pjmedia_sdp_conn *c)
+{
+    CHECK( c, PJ_EINVAL);
+    CHECK( pj_strcmp2(&c->net_type, "IN")==0, PJMEDIA_SDP_EINCONN);
+    CHECK( pj_strcmp2(&c->addr_type, "IP4")==0 ||
+	   pj_strcmp2(&c->addr_type, "IP6")==0, 
+	   PJMEDIA_SDP_EINCONN);
+    CHECK( c->addr.slen != 0, PJMEDIA_SDP_EINCONN);
+
+    return PJ_SUCCESS;
+}
+
+
+/* Validate SDP session descriptor. */
+PJ_DEF(pj_status_t) pjmedia_sdp_validate(const pjmedia_sdp_session *sdp)
+{
+    unsigned i;
+    const pj_str_t STR_RTPMAP = { "rtpmap", 6 };
+
+    CHECK( sdp != NULL, PJ_EINVAL);
+
+    /* Validate origin line. */
+    CHECK( sdp->origin.user.slen != 0, PJMEDIA_SDP_EINORIGIN);
+    CHECK( pj_strcmp2(&sdp->origin.net_type, "IN")==0, 
+	   PJMEDIA_SDP_EINORIGIN);
+    CHECK( pj_strcmp2(&sdp->origin.addr_type, "IP4")==0 ||
+	   pj_strcmp2(&sdp->origin.addr_type, "IP6")==0, 
+	   PJMEDIA_SDP_EINORIGIN);
+    CHECK( sdp->origin.addr.slen != 0, PJMEDIA_SDP_EINORIGIN);
+
+    /* Validate subject line. */
+    CHECK( sdp->name.slen != 0, PJMEDIA_SDP_EINNAME);
+
+    /* Ignore start and stop time. */
+
+    /* If session level connection info is present, validate it. */
+    if (sdp->conn) {
+	pj_status_t status = validate_sdp_conn(sdp->conn);
+	if (status != PJ_SUCCESS)
+	    return status;
+    }
+
+    /* Validate each media. */
+    for (i=0; i<sdp->media_count; ++i) {
+	const pjmedia_sdp_media *m = sdp->media[i];
+	unsigned j;
+
+	/* Validate the m= line. */
+	CHECK( m->desc.media.slen != 0, PJMEDIA_SDP_EINMEDIA);
+	CHECK( m->desc.transport.slen != 0, PJMEDIA_SDP_EINMEDIA);
+	CHECK( m->desc.fmt_count != 0 || m->desc.port==0, PJMEDIA_SDP_ENOFMT);
+
+	/* If media level connection info is present, validate it. */
+	if (m->conn) {
+	    pj_status_t status = validate_sdp_conn(m->conn);
+	    if (status != PJ_SUCCESS)
+		return status;
+	}
+
+	/* If media doesn't have connection info, then connection info
+	 * must be present in the session.
+	 */
+	if (m->conn == NULL) {
+	    if (sdp->conn == NULL)
+		return PJMEDIA_SDP_EMISSINGCONN;
+	}
+
+	/* Verify payload type. */
+	for (j=0; j<m->desc.fmt_count; ++j) {
+
+	    /* Arrgh noo!! Payload type can be non-numeric!!
+	     * RTC based programs sends "null" for instant messaging!
+	     */
+	    if (pj_isdigit(*m->desc.fmt[j].ptr)) {
+		unsigned pt = pj_strtoul(&m->desc.fmt[j]);
+
+		/* Payload type is between 0 and 127. 
+		 */
+		CHECK( pt <= 127, PJMEDIA_SDP_EINPT);
+
+		/* If port is not zero, then for each dynamic payload type, an
+		 * rtpmap attribute must be specified.
+		 */
+		if (m->desc.port != 0 && pt >= 96) {
+		    const pjmedia_sdp_attr *a;
+
+		    a = pjmedia_sdp_media_find_attr(m, &STR_RTPMAP, 
+						    &m->desc.fmt[j]);
+		    CHECK( a != NULL, PJMEDIA_SDP_EMISSINGRTPMAP);
+		}
+	    }
+	}
+    }
+
+    /* Looks good. */
+    return PJ_SUCCESS;
+}
+
+PJ_DEF(pj_status_t) pjmedia_sdp_transport_cmp( const pj_str_t *t1,
+					       const pj_str_t *t2)
+{
+    static const pj_str_t ID_RTP_AVP  = { "RTP/AVP", 7 };
+    static const pj_str_t ID_RTP_SAVP = { "RTP/SAVP", 8 };
+
+    /* Exactly equal? */
+    if (pj_stricmp(t1, t2) == 0)
+	return PJ_SUCCESS;
+
+    /* Compatible? */
+    if ((!pj_stricmp(t1, &ID_RTP_AVP) || !pj_stricmp(t1, &ID_RTP_SAVP)) &&
+        (!pj_stricmp(t2, &ID_RTP_AVP) || !pj_stricmp(t2, &ID_RTP_SAVP)))
+	return PJ_SUCCESS;
+
+    return PJMEDIA_SDP_ETPORTNOTEQUAL;
+}
+
+
+PJ_DEF(pj_status_t) pjmedia_sdp_media_deactivate(pj_pool_t *pool,
+						 pjmedia_sdp_media *m)
+{
+    PJ_ASSERT_RETURN(m, PJ_EINVAL);
+    PJ_UNUSED_ARG(pool);
+
+    /* Set port to zero */
+    m->desc.port = 0;
+
+    /* And remove attributes */
+    m->attr_count = 0;
+
+    return PJ_SUCCESS;
+}
+
+
+PJ_DEF(pjmedia_sdp_media*) pjmedia_sdp_media_clone_deactivate(
+						pj_pool_t *pool,
+						const pjmedia_sdp_media *rhs)
+{
+    unsigned int i;
+    pjmedia_sdp_media *m;
+
+    PJ_ASSERT_RETURN(pool && rhs, NULL);
+
+    m = PJ_POOL_ZALLOC_T(pool, pjmedia_sdp_media);
+    pj_memcpy(m, rhs, sizeof(*m));
+
+    /* Clone the media line only */
+    pj_strdup (pool, &m->desc.media, &rhs->desc.media);
+    pj_strdup (pool, &m->desc.transport, &rhs->desc.transport);
+    for (i=0; i<rhs->desc.fmt_count; ++i)
+	pj_strdup(pool, &m->desc.fmt[i], &rhs->desc.fmt[i]);
+
+    if (rhs->conn) {
+	m->conn = pjmedia_sdp_conn_clone (pool, rhs->conn);
+	PJ_ASSERT_RETURN(m->conn != NULL, NULL);
+    }
+
+    m->bandw_count = rhs->bandw_count;
+    for (i=0; i < rhs->bandw_count; ++i) {
+	m->bandw[i] = pjmedia_sdp_bandw_clone (pool, rhs->bandw[i]);
+	PJ_ASSERT_RETURN(m->bandw[i] != NULL, NULL);
+    }
+
+    /* And deactivate it */
+    pjmedia_sdp_media_deactivate(pool, m);
+
+    return m;
+}