sdp_parse.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

  post_session(p, sdp);
}

int sdp_connection_is_inaddr_any(sdp_connection_t const *c)
{
  return 
    c && 
    c->c_nettype == sdp_net_in && 
    ((c->c_addrtype == sdp_addr_ip4 && strcmp(c->c_address, "0.0.0.0")) ||
     (c->c_addrtype == sdp_addr_ip6 && strcmp(c->c_address, "::")));
}

/**Postprocess session description.
 *
 * The function post_session() postprocesses the session description. The
 * postprocessing includes setting the session backpointer for each media.
 */
static void post_session(sdp_parser_t *p, sdp_session_t *sdp)
{
  sdp_media_t *m;
  sdp_connection_t const *c;

  if (!p->pr_ok)
    return;

  /* Set session back-pointer */
  for (m = sdp->sdp_media; m; m = m->m_next) {
    m->m_session = sdp;
  }

  if (p->pr_config) {
    if (sdp->sdp_version[0] != 0)
      parsing_error(p, "Incorrect version");
    return;
  }
  
  /* Go through all media and set mode */
  for (m = sdp->sdp_media; m; m = m->m_next) {
    if (m->m_port == 0) {
      m->m_mode = sdp_inactive;
      m->m_rejected = 1;
      continue;
    }

    c = sdp_media_connections(m);

    if (p->pr_mode_0000 && c) {
      if (c->c_nettype == sdp_net_in &&
	  c->c_addrtype == sdp_addr_ip4 &&
	  strcmp(c->c_address, "0.0.0.0") == 0)
	/* Reset recvonly flag */
	m->m_mode &= ~sdp_recvonly;
    }
  }

  if (p->pr_insane)
    return;

  /* Verify that all mandatory fields are present */
  if (sdp_sanity_check(p) < 0)
    return;
}

/** Validates that all mandatory fields exist 
 *
 * Checks that all necessary fields (v=, o=) exists in the parsed sdp. If
 * strict, check that all mandatory fields (c=, o=, s=, t=) are present. 
 * This function also goes through all media, marks rejected media as such,
 * and updates the mode accordingly.
 * 
 * @retval 0 if parsed SDP description is valid
 * @retval -1 if some SDP line is missing
 * @retval -2 if c= line is missing
 */
int sdp_sanity_check(sdp_parser_t *p)
{
  sdp_session_t *sdp = p->pr_session;
  sdp_media_t *m;

  if (!p || !p->pr_ok)
    return -1;
  else if (sdp->sdp_version[0] != 0)
    return parsing_error(p, "Incorrect version");
  else if (!sdp->sdp_origin)
    return parsing_error(p, "No o= present");
  else if (p->pr_strict && !sdp->sdp_subject)
    return parsing_error(p, "No s= present");
  else if (p->pr_strict && !sdp->sdp_time)
    return parsing_error(p, "No t= present");

  /* If there is no session level c= check that one exists for all media */
  /* c= line may be missing if this is a RTSP description */
  if (!p->pr_c_missing && !sdp->sdp_connection) {
    for (m = sdp->sdp_media ; m ; m = m->m_next) {
      if (!m->m_connections && !m->m_rejected) {
	parsing_error(p, "No c= on either session level or all mediums");
	return -2;
      }
    }
  }

  return 0;
}

#if 0
/**
 * Parse a "v=" field
 *
 * The function parser_version() parses the SDP version field.
 *
 * @param p      pointer to SDP parser object
 * @param r      pointer to record data
 * @param result pointer to which parsed record is assigned
 */
static void parse_version(sdp_parser_t *p, char *r, sdp_version_t *result)
{
  /*
   proto-version =       "v=" 1*DIGIT CRLF
                         ;[RFC2327] describes version 0
   */
  if (parse_ul(p, &r, result, 0))
    parsing_error(p, "version \"%s\" is invalid", r);
  else if (*result > 0)
    parsing_error(p, "unknown version v=%s", r);
}
#endif

/* -------------------------------------------------------------------------
 * Function parse_origin() - parse an "o=" field
 *
 * Description:
 *   This function parses an SDP origin field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_origin(sdp_parser_t *p, char *r, sdp_origin_t **result)
{
  /*
   origin-field =        "o=" username space
                         sess-id space sess-version space
                         nettype space addrtype space
                         addr CRLF

   username =            safe
                         ;pretty wide definition, but doesn't include space

   sess-id =             1*(DIGIT)
                         ;should be unique for this originating username/host

   sess-version =        1*(DIGIT)
                         ;0 is a new session

			 
   */
  PARSE_ALLOC(p, sdp_origin_t, o);

  *result = o;

  o->o_username = token(&r, SPACE TAB, NULL, SPACE TAB);
  if (!o->o_username) {
    parsing_error(p, "invalid username");
    return;
  }
  if (parse_ull(p, &r, &o->o_id, 0)) {
    parsing_error(p, "invalid session id");
    return;
  }

  if (parse_ull(p, &r, &o->o_version, 0)) {
    parsing_error(p, "invalid session version");
    return;
  }

  parse_connection(p, r, &o->o_address);
}

/* -------------------------------------------------------------------------
 * Function parse_subject() - parse an "s=" field
 *
 * Description:
 *   This function parses an SDP subject field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_subject(sdp_parser_t *p, char *r, sdp_text_t **result)
{
  /*
   session-name-field =  "s=" text CRLF
   text =                byte-string
   */
  *result = r;
}

/* -------------------------------------------------------------------------
 * Function parse_information() - parse an "i=" field
 *
 * Description:
 *   This function parses an SDP information field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_information(sdp_parser_t *p, char *r, sdp_text_t **result)
{
  /*
   information-field =   ["i=" text CRLF]
   */
  *result = r;
}

/* -------------------------------------------------------------------------
 * Function parse_uri() - parse an "u=" field
 *
 * Description:
 *   This function parses an SDP URI field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_uri(sdp_parser_t *p, char *r, sdp_text_t **result)
{
  /*
    uri-field =           ["u=" uri CRLF]

    uri=                  ;defined in RFC1630
  */
  /* XXX - no syntax checking here */
  *result = r;
}

/* -------------------------------------------------------------------------
 * Function parse_email() - parse an "e=" field
 *
 * Description:
 *   This function parses an SDP email field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_email(sdp_parser_t *p, char *r, sdp_list_t **result)
{
  /*
   email-fields =        *("e=" email-address CRLF)

   email-address =       email | email "(" email-safe ")" |
                         email-safe "<" email ">"

   email =               ;defined in RFC822  */
  parse_text_list(p, r, result);
}

/* -------------------------------------------------------------------------
 * Function parse_phone() - parse an "p=" field
 *
 * Description:
 *   This function parses an SDP phone field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_phone(sdp_parser_t *p, char *r, sdp_list_t **result)
{
  /*
   phone-fields =        *("p=" phone-number CRLF)

   phone-number =        phone | phone "(" email-safe ")" |
                         email-safe "<" phone ">"

   phone =               "+" POS-DIGIT 1*(space | "-" | DIGIT)
                         ;there must be a space or hyphen between the
                         ;international code and the rest of the number.
  */
  parse_text_list(p, r, result);
}

/* -------------------------------------------------------------------------
 * Function parse_connection() - parse an "c=" field
 *
 * Description:
 *   This function parses an SDP connection field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_connection(sdp_parser_t *p, char *r, sdp_connection_t **result)
{
  /*
   connection-field =    ["c=" nettype space addrtype space
                         connection-address CRLF]
                         ;a connection field must be present
                         ;in every media description or at the
                         ;session-level

   nettype =             "IN"
                         ;list to be extended

   addrtype =            "IP4" | "IP6"
                         ;list to be extended

   connection-address =  multicast-address
                         | addr

   multicast-address =   3*(decimal-uchar ".") decimal-uchar "/" ttl
                         [ "/" integer ]
                         ;multicast addresses may be in the range
                         ;224.0.0.0 to 239.255.255.255

   ttl =                 decimal-uchar

   addr =                FQDN | unicast-address

   FQDN =                4*(alpha-numeric|"-"|".")
                         ;fully qualified domain name as specified in RFC1035

   unicast-address =     IP4-address | IP6-address

   IP4-address =         b1 "." decimal-uchar "." decimal-uchar "." b4
   b1 =                  decimal-uchar
                         ;less than "224"; not "0" or "127"
   b4 =                  decimal-uchar
                         ;not "0"

   IP6-address =         ;to be defined
   */
  PARSE_ALLOC(p, sdp_connection_t, c);

  *result = c;

  if (strncasecmp(r, "IN", 2) == 0) {
    char *s;

    /* nettype is internet */
    c->c_nettype = sdp_net_in;
    s = token(&r, SPACE TAB, NULL, NULL);

    /* addrtype */
    s = token(&r, SPACE TAB, NULL, NULL);
    if (s && strcasecmp(s, "IP4") == 0)
      c->c_addrtype = sdp_addr_ip4;
    else if (s && strcasecmp(s, "IP6") == 0)
      c->c_addrtype = sdp_addr_ip6;
    else {
      parsing_error(p, "unknown IN address type: %s", s);
      return;
    }

    /* address */
    s = next(&r, SPACE TAB, SPACE TAB);
    c->c_address = s;
    if (!s || !*s) {
      parsing_error(p, "invalid address");
      return;
    }

    /* ttl */
    s = strchr(s, '/');
    if (s) {
      unsigned long value;
      *s++ = 0;
      if (parse_ul(p, &s, &value, 256) ||
	  (*s && *s != '/')) {
	parsing_error(p, "invalid ttl");
	return;
      }
      c->c_ttl = value;
      c->c_mcast = 1;

      /* multiple groups */
      value = 1;
      if (*s++ == '/')
	if (parse_ul(p, &s, &value, 0) || *s) {
	  parsing_error(p, "invalid number of multicast groups");
	  return;
	}
      c->c_groups = value;
    }
    else
      c->c_groups = 1;
  }
  else if (p->pr_anynet) {
    c->c_nettype = sdp_net_x;
    c->c_addrtype = sdp_addr_x;
    c->c_address = r;
    c->c_ttl = 0;
    c->c_groups = 1;
  }
  else 
    parsing_error(p, "invalid address");
}

/* -------------------------------------------------------------------------
 * Function parse_bandwidth() - parse an "b=" field
 *
 * Description:
 *   This function parses an SDP bandwidth field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_bandwidth(sdp_parser_t *p, char *r, sdp_bandwidth_t **result)
{
  /*
   bandwidth-fields =    *("b=" bwtype ":" bandwidth CRLF)

   bwtype =              1*(alpha-numeric)
                         ; CT or AS
   bandwidth =           1*(DIGIT)
   */
  /* NOTE: bwtype can also be like X-barf */
  sdp_bandwidth_e modifier;
  char *name;
  unsigned long value;

  name = token(&r, ":", ALPHA DIGIT "-", SPACE TAB);

  if (name == NULL || parse_ul(p, &r, &value, 0)) {
    parsing_error(p, "invalid bandwidth");
    return;
  }

  if (strcmp(name, "CT") == 0)
    modifier = sdp_bw_ct, name = NULL;
  else if (strcmp(name, "AS") == 0)
    modifier = sdp_bw_as, name = NULL;
  else
    modifier = sdp_bw_x;

  if (STRICT(p))
    PARSE_CHECK_REST(p, r, "b");
  
  {
    PARSE_ALLOC(p, sdp_bandwidth_t, b);
    *result = b;
    b->b_modifier = modifier;
    b->b_modifier_name = name;
    b->b_value = value;
  }
}

/* -------------------------------------------------------------------------
 * Function parse_time() - parse an "t=" field
 *
 * Description:
 *   This function parses an SDP time field.
 *
 * Parameters:
 *   p      - pointer to SDP parser object
 *   r      - pointer to record data
 *   result - pointer to which parsed record is assigned
 */
static void parse_time(sdp_parser_t *p, char *r, sdp_time_t **result)
{
  /*
   time-fields =         1*( "t=" start-time space stop-time