sdp.c

一个开源SIP协议栈

/* $Id: sdp.c 974 2007-02-19 01:13:53Z bennylp $ */
/* 
 * Copyright (C) 2003-2007 Benny Prijono <[e-mail]>
 *
 * 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,
};
#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 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(pool, sizeof(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(pool, sizeof(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;

    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) {
		if (a->value.slen > c_fmt->slen &&
		    pj_strncmp(&a->value, c_fmt, c_fmt->slen)==0)
		{
		    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);

    /* 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')
    {
	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(SYNTAX_ERROR) {
	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);

    /* 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(SYNTAX_ERROR) {
	status = PJMEDIA_SDP_EINRTCP;
    }
    PJ_END;

    pj_scan_fini(&scanner);
    return status;
}



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(pool, sizeof(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)