soa_static.c

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

 *
 * @retval 1 if session was changed (or to be changed, if @a dryrun is nonzero)
 */ 
static
int soa_sdp_mode_set(sdp_session_t const *user,
		     int const *s2u,
		     sdp_session_t *session,
		     sdp_session_t const *remote,
		     char const *hold,
		     int dryrun)
{
  sdp_media_t *sm;
  sdp_media_t const *rm, *rm_next, *um;
  int retval = 0, i, j;
  int hold_all;
  int inactive_all;
  int inactive = 0;
  char const *hold_media = NULL;
  sdp_mode_t send_mode, recv_mode;

  SU_DEBUG_7(("soa_sdp_mode_set(%p, %p, \"%s\"): called\n",
	      (void *)session, (void *)remote, hold ? hold : ""));

  if (!session || !session->sdp_media)
    return 0;

  rm = remote ? remote->sdp_media : NULL, rm_next = NULL;

  hold_all = str0cmp(hold, "*") == 0;
  inactive_all = str0cmp(hold, "#") == 0;

  i = 0;

  for (sm = session->sdp_media; sm; sm = sm->m_next, rm = rm_next, i++) {
    rm_next = rm ? rm->m_next : NULL;
    inactive = 0;

    if (sm->m_rejected)
      continue;

    assert(s2u);

    for (j = 0, um = user->sdp_media; j != s2u[i]; um = um->m_next, j++)
      assert(um);
    if (um == NULL) {
      if (dryrun)
	return 1;
      else
	retval = 1;
      sm->m_rejected = 1;
      sm->m_mode = sdp_inactive;
      sm->m_port = 0;
      continue;
    }

    send_mode = um->m_mode & sdp_sendonly;
    if (rm)
      send_mode = (rm->m_mode & sdp_recvonly) ? sdp_sendonly : 0;

    recv_mode = um->m_mode & sdp_recvonly;

    if (rm && rm->m_mode == sdp_inactive) {
      send_mode = recv_mode = 0;
    }
    else if (inactive_all) {
      send_mode = recv_mode = 0;
    }
    else if (hold_all) {
      recv_mode = 0;
    }
    else if (hold && (hold_media = strcasestr(hold, sm->m_type_name))) {
      recv_mode = 0;
      hold_media += strlen(sm->m_type_name);
      hold_media += strspn(hold_media, " \t");
      if (hold_media[0] == '=') {
	hold_media += strspn(hold, " \t");
	if (strncasecmp(hold_media, "inactive", strlen("inactive")) == 0)
	  recv_mode = send_mode = 0;
      }
    }

    if (sm->m_mode != (unsigned)(recv_mode | send_mode)) {
      if (dryrun)
	return 1;
      else
	retval = 1;
      sm->m_mode = recv_mode | send_mode;
    }
  }

  return retval;
}

enum offer_answer_action {
  generate_offer,
  generate_answer,
  process_answer
};

/**
 * Updates the modified copy of local SDP based
 * on application provided local SDP and remote SDP.
 */
static int offer_answer_step(soa_session_t *ss,
			     enum offer_answer_action action,
			     char const *by)
{
  soa_static_session_t *sss = (soa_static_session_t *)ss;

  char c_address[64];
  sdp_session_t *local = ss->ss_local->ssd_sdp;
  sdp_session_t local0[1];

  sdp_session_t *user = ss->ss_user->ssd_sdp;
  unsigned user_version = ss->ss_user_version;

  sdp_session_t *remote = ss->ss_remote->ssd_sdp;
  unsigned remote_version = ss->ss_remote_version;

  sdp_origin_t o[1] = {{ sizeof(o) }};
  sdp_connection_t *c, c0[1] = {{ sizeof(c0) }};
  sdp_time_t t[1] = {{ sizeof(t) }};

  int *u2s = NULL, *s2u = NULL, *tbf;

  char const *phrase = "Internal Media Error";

  su_home_t tmphome[SU_HOME_AUTO_SIZE(8192)];

  su_home_auto(tmphome, sizeof tmphome);

  SU_DEBUG_7(("soa_static_offer_answer_action(%p, %s): called\n",
	      (void *)ss, by));

  if (user == NULL)
    return soa_set_status(ss, 500, "No session set by user");

  if (action == generate_offer)
    remote = NULL;
  else if (remote == NULL)
    return soa_set_status(ss, 500, "No remote SDP");

  /* Pre-negotiation Step: Expand truncated remote SDP */
  if (local && remote) switch (action) {
  case generate_answer:
  case process_answer:
    if (sdp_media_count(remote, sdp_media_any, "*", 0, 0) < 
	sdp_media_count(local, sdp_media_any, "*", 0, 0)) {
      SU_DEBUG_5(("%s: remote %s is truncated: expanding\n",
		  by, action == generate_answer ? "offer" : "answer"));
      remote = soa_sdp_expand_media(tmphome, remote, local);
      if (remote == NULL)
	return soa_set_status(ss, 500, "Cannot expand remote session");
    }
  default:
    break;
  }
  
  /* Step A: Create local SDP session (based on user-supplied SDP) */
  if (local == NULL) switch (action) {
  case generate_offer:
  case generate_answer:
    SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by,
		"generating local description"));

    local = local0;
    *local = *user, local->sdp_media = NULL;

    if (local->sdp_origin) {
      o->o_username = local->sdp_origin->o_username;
      /* o->o_address = local->sdp_origin->o_address; */
    }
    if (!o->o_address)
      o->o_address = c0; 
    local->sdp_origin = o;

    if (soa_init_sdp_origin(ss, o, c_address) < 0) {
      phrase = "Cannot Get IP Address for Media";
      goto internal_error;
    }

    break;

  case process_answer:
  default:
    goto internal_error;
  }

  /* Step B: upgrade local SDP (add m= lines to it)  */
  switch (action) {
  case generate_offer:
    /* Upgrade local SDP based on user SDP */
    if (local != local0 && ss->ss_local_user_version == user_version)
      break;
    if (local != local0)
      *local0 = *local, local = local0;
    SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by, 
		"upgrade with local description"));
    if (soa_sdp_upgrade(ss, tmphome, local, user, NULL, &u2s, &s2u) < 0)
      goto internal_error;
    break;
  case generate_answer:
    /* Upgrade local SDP based on remote SDP */
    if (ss->ss_local_user_version == user_version &&
	ss->ss_local_remote_version == remote_version)
      break;
    if (1) {
      if (local != local0)
	*local0 = *local, local = local0;
      SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by,
		  "upgrade with remote description"));
      if (soa_sdp_upgrade(ss, tmphome, local, user, remote, &u2s, &s2u) < 0)
	goto internal_error;
    }
    break;
  case process_answer:
  default:
    break;
  }


  /* Step C: reject media */
  switch (action) {
  case generate_offer:
    /* Local media is marked as rejected already in upgrade phase */
    break;
  case generate_answer:
  case process_answer:
    if (ss->ss_local_remote_version == remote_version)
      break;
    if (soa_sdp_reject_is_needed(local, remote)) {
      if (local != local0) {
	*local0 = *local, local = local0;
#define DUP_LOCAL(local)					 \
	do {							 \
	  if (!local->sdp_media) break;				 \
	  local->sdp_media =					 \
	    sdp_media_dup_all(tmphome, local->sdp_media, local); \
	  if (!local->sdp_media)				 \
	    goto internal_error;				 \
	} while (0)
	DUP_LOCAL(local);
      }
      SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by, 
		  "marking rejected media"));
      soa_sdp_reject(tmphome, local, remote);
    }
    break;
  default:
    break;
  }

  /* Step D: Set media mode bits */
  switch (action) {
    int const *s2u_;

  case generate_offer:
  case generate_answer:
  case process_answer:
    s2u_ = s2u;

    if (!s2u_) s2u_ = sss->sss_s2u;

    if (soa_sdp_mode_set(user, s2u_, local, remote, ss->ss_hold, 1)) {
      if (local != local0) {
	*local0 = *local, local = local0;
	DUP_LOCAL(local);
      }

      soa_sdp_mode_set(user, s2u_, local, remote, ss->ss_hold, 0);
    }
    break;
  default:
    break;
  }

  /* Step E: Upgrade codecs by answer. */
  switch (action) {
  case process_answer:
    /* Upgrade local SDP based on remote SDP */
    if (ss->ss_local_remote_version == remote_version)
      break;
    if (1 /* We don't have good test for codecs */) {
      SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by,
		  "upgrade codecs with remote description"));
      if (local != local0) {
	*local0 = *local, local = local0; 
	DUP_LOCAL(local);
      }
      soa_sdp_session_upgrade_rtpmaps(ss, local, remote);
    }
    break;
  case generate_offer:
  case generate_answer:
  default:
    break;
  }

  /* Step F: Update c= line */ 
  switch (action) {
  case generate_offer:
  case generate_answer:
    /* Upgrade local SDP based of user SDP */
    if (ss->ss_local_user_version == user_version &&
	local->sdp_connection)
      break;

    if (local->sdp_connection == NULL || 
	(user->sdp_connection != NULL && 
	 sdp_connection_cmp(local->sdp_connection, user->sdp_connection))) {
      sdp_media_t *m;

      /* Every m= line (even rejected one) must have a c= line 
       * or there must be a c= line at session level
       */
      if (user->sdp_connection)
	c = user->sdp_connection;
      else
	c = local->sdp_origin->o_address;

      for (m = local->sdp_media; m; m = m->m_next)
	if (m->m_connections == NULL)
	  break;

      if (m) {
	if (local != local0) {
	  *local0 = *local, local = local0; 
	  DUP_LOCAL(local);
	}
	local->sdp_connection = c;
      }
    }
    break;

  default:
    break;
  }

  soa_description_free(ss, ss->ss_previous);

  if (u2s) {
    u2s = u2s_alloc(ss->ss_home, u2s); 
    s2u = u2s_alloc(ss->ss_home, s2u);
    if (!u2s || !s2u)
      goto internal_error;
  }

  if (ss->ss_local->ssd_sdp != local &&
      sdp_session_cmp(ss->ss_local->ssd_sdp, local)) {
    /* We have modified local session: update origin-line */
    if (local->sdp_origin != o)
      *o = *local->sdp_origin, local->sdp_origin = o;
    o->o_version++;

    /* Do sanity checks for the created SDP */
    if (!local->sdp_subject)	/* s= is mandatory */
      local->sdp_subject = "-";
    if (!local->sdp_time)	/* t= is mandatory */
      local->sdp_time = t;

    if (action == generate_offer) {
      /* Keep a copy of previous session state */
      *ss->ss_previous = *ss->ss_local;
      memset(ss->ss_local, 0, (sizeof *ss->ss_local));
      ss->ss_previous_user_version = ss->ss_local_user_version;
      ss->ss_previous_remote_version = ss->ss_local_remote_version;
    }

    SU_DEBUG_7(("soa_static(%p, %s): %s\n", (void *)ss, by,
		"storing local description"));

    /* Update the unparsed and pretty-printed descriptions  */
    if (soa_description_set(ss, ss->ss_local, local, NULL, 0) < 0) {
      if (action == generate_offer) {
	/* Remove 2nd reference to local session state */
	memset(ss->ss_previous, 0, (sizeof *ss->ss_previous));
	ss->ss_previous_user_version = 0;
	ss->ss_previous_remote_version = 0;
      }
      
      su_free(ss->ss_home, u2s), su_free(ss->ss_home, s2u);

      goto internal_error;
    }
  }

  if (u2s) {
    tbf = sss->sss_u2s, sss->sss_u2s = u2s, su_free(ss->ss_home, tbf);
    tbf = sss->sss_s2u, sss->sss_s2u = s2u, su_free(ss->ss_home, tbf);
  }

  /* Update version numbers */
  switch (action) {
  case generate_offer:
    ss->ss_local_user_version = user_version;
    break;
  case generate_answer:
    ss->ss_local_user_version = user_version;
    ss->ss_local_remote_version = remote_version;
    break;
  case process_answer:
    ss->ss_local_remote_version = remote_version;
  default:
    break;
  }

  su_home_deinit(tmphome);
  return 0;

 internal_error:
  su_home_deinit(tmphome);
  return soa_set_status(ss, 500, phrase);
}

/**
 * Generates offer based on local SDP.
 */
static int soa_static_generate_offer(soa_session_t *ss,
				     soa_callback_f *completed)
{
  if (!ss->ss_user->ssd_sdp)
    return soa_set_status(ss, 500, "No session set by user");

  if (offer_answer_step(ss, generate_offer, "soa_generate_offer") < 0)
    return -1;

  return soa_base_generate_offer(ss, NULL);
}

static int soa_static_generate_answer(soa_session_t *ss,
				      soa_callback_f *completed)
{
  /* NOTE:
   * - local SDP might have changed
   * - remote SDP might have been updated 
   */

  if (offer_answer_step(ss, generate_answer, "soa_generate_answer") < 0)
    return -1;

  return soa_base_generate_answer(ss, NULL);
}

static int soa_static_process_answer(soa_session_t *ss,
				     soa_callback_f *completed)
{
  /* NOTE:
   * - both local and remote information is available
   * - local SDP might have changed
   * - remote SDP might have been updated 
   */
  if (offer_answer_step(ss, process_answer, "soa_process_answer") < 0)
    return -1;

  return soa_base_process_answer(ss, NULL);
}

/** Process rejected offer */
static int soa_static_process_reject(soa_session_t *ss,
				     soa_callback_f *completed)
{
  struct soa_description d[1];

  *d = *ss->ss_local;
  *ss->ss_local = *ss->ss_previous;
  ss->ss_local_user_version = ss->ss_previous_user_version;
  ss->ss_local_remote_version = ss->ss_previous_remote_version;

  memset(ss->ss_previous, 0, (sizeof *ss->ss_previous));
  soa_description_free(ss, d);

  return soa_base_process_reject(ss, NULL);
}

static int soa_static_activate(soa_session_t *ss, char const *option)
{
  return soa_base_activate(ss, option);
}

static int soa_static_deactivate(soa_session_t *ss, char const *option)
{
  return soa_base_deactivate(ss, option);
}

static void soa_static_terminate(soa_session_t *ss, char const *option)
{
  soa_description_free(ss, ss->ss_user);
  soa_base_terminate(ss, option);
}