sdp.c

一个开源SIP协议栈

{
    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(pool, sizeof(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 > sizeof(tempbuf))
	return PJMEDIA_SDP_ERTPMAPTOOLONG;

    attr->value.slen = len;
    attr->value.ptr = pj_pool_alloc(pool, attr->value.slen);
    pj_memcpy(attr->value.ptr, tempbuf, attr->value.slen);

    *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 (pool, sizeof(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;
}

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 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 (pool, sizeof(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->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(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;
    }


    /* 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", &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", &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;