nta.c

this is simple sip stack.

/** Add a transport to the agent.
 *
 * The function nta_agent_add_tport() creates a new transport and binds it
 * to the port specified by the @a uri. The @a uri must have sip: or sips:
 * scheme or be a wildcard uri ("*"). The @a uri syntax allowed is as
 * follows:
 *
 * @code url <scheme>:<host>[:<port>]<url-params> @endcode
 * where <url-params> may be
 * @code
 * ;transport=<xxx>
 * ;maddr=<actual addr>
 * ;comp=sigcomp
 * @endcode
 *
 * The scheme part determines which transports are used. "sip" implies UDP
 * and TCP, "sips" TLS over TCP. In the future, more transports can be
 * supported, for instance, "sip" can use SCTP or DCCP, "sips" DTLS or TLS
 * over SCTP.
 *
 * The "host" part determines what address/domain name is used in Contact.
 * An "*" in "host" part is shorthand for any local IP address. 0.0.0.0
 * means that the only the IPv4 addresses are used. [::] means that only
 * the IPv6 addresses are used. If a domain name or a specific IP address
 * is given as "host" part, an additional "maddr" parameter can be used to
 * control which addresses are used by the stack when binding listen
 * sockets for incoming requests.
 *
 * The "port" determines what port is used in contact, and to which port the
 * stack binds in order to listen for incoming requests. Empty or missing
 * port means that default port should be used (5060 for sip, 5061 for
 * sips). An "*" in "port" part means any port, i.e., the stack binds to an
 * ephemeral port.
 *
 * The "transport" parameter determines the transport protocol that is used
 * and how they are preferred. If no protocol is specified, both UDP and TCP
 * are used for SIP URL and TLS for SIPS URL. The preference can be
 * indicated with a comma-separated list of transports, for instance,
 * parameter @code transport=tcp,udp @endocde indicates that TCP is
 * preferred to UDP.
 *
 * The "maddr" parameter determines to which address the stack binds in
 * order to listen for incoming requests. An "*" in "maddr" parameter is
 * shorthand for any local IP address. 0.0.0.0 means that only IPv4 sockets
 * are created. [::] means that only IPv6 sockets are created.
 *
 * The "comp" parameter determines the supported compression protocol.
 * Currently only sigcomp is supported (with suitable library.
 *
 * @par Examples:
 * @code sip:172.21.40.24;maddr=* @endcode \n
 * @code sip:172.21.40.24:50600;transport=TCP,UDP;comp=sigcomp @endcode \n
 * @code sips:* @endcode
 *
 * @return
 * On success, zero is returned. On error, -1 is returned, and @a errno is
 * set appropriately.
 */
int nta_agent_add_tport(nta_agent_t *self,
			url_string_t const *uri,
			tag_type_t tag, tag_value_t value, ...)
{
  url_t *url;
  char tp[32];
  char maddr[256];
  char comp[32];
  tp_name_t tpn[1] = {{ NULL }};
  char const * const * tports = tports_sip;
  int error;
  ta_list ta;

  if (self == NULL) {
    su_seterrno(EINVAL);
    return -1;
  }

  if (uri == NULL)
    uri = (url_string_t *)"sip:*";
  else if (url_string_p(uri) ?
	   strcmp(uri->us_str, "*") == 0 :
	   uri->us_url->url_type == url_any) {
    uri = (url_string_t *)"sip:*:*";
  }

  if (!(url = url_hdup(self->sa_home, uri->us_url)) ||
      (url->url_type != url_sip && url->url_type != url_sips)) {
    if (url_string_p(uri))
      SU_DEBUG_1(("nta: %s: invalid bind URL\n", uri->us_str));
    else
      SU_DEBUG_1(("nta: invalid bind URL\n"));
    su_seterrno(EINVAL);
    return -1;
  }

  tpn->tpn_canon = url->url_host;
  tpn->tpn_host = url->url_host;
  tpn->tpn_port = url_port(url);

  if (url->url_type == url_sip) {
    tpn->tpn_proto = "*";
    tports = tports_sip;
    if (!tpn->tpn_port || !tpn->tpn_port[0]) 
      tpn->tpn_port = SIP_DEFAULT_SERV;
  }
  else {
    assert(url->url_type == url_sips);
    tpn->tpn_proto = "*";
    tports = tports_sips;
    if (!tpn->tpn_port || !tpn->tpn_port[0]) 
      tpn->tpn_port = SIPS_DEFAULT_SERV;
  }

  if (url->url_params) {
    if (url_param(url->url_params, "transport", tp, sizeof(tp)) > 0) {
      if (strchr(tp, ',')) {
	int i; char *t, *tps[9];

	/* Split tp into transports */
	for (i = 0, t = tp; t && i < 8; i++) {
	  tps[i] = t;
	  if ((t = strchr(t, ',')))
	    *t++ = '\0';
	}

	tps[i] = NULL;
	tports = (char const * const *)tps;
      } else {
	tpn->tpn_proto = tp;
      }
    }
    if (url_param(url->url_params, "maddr", maddr, sizeof(maddr)) > 0)
      tpn->tpn_host = maddr;
    if (url_param(url->url_params, "comp", comp, sizeof(comp)) > 0)
      tpn->tpn_comp = comp;

    if (tpn->tpn_comp && 
	(nta_compressor_vtable == NULL || 
	 strcasecmp(tpn->tpn_comp, nta_compressor_vtable->ncv_name) != 0)) {
      SU_DEBUG_1(("nta(%p): comp=%s not supported for " URL_PRINT_FORMAT "\n",
		  self, tpn->tpn_comp, URL_PRINT_ARGS(url)));
    }
  }

  ta_start(ta, tag, value);

  if (self->sa_tports == NULL) {
    if (agent_create_master_transport(self, ta_args(ta)) < 0) {
      error = su_errno();
      SU_DEBUG_1(("nta: cannot create master transport: %s\n",
		  su_strerror(error)));
      goto error;
    }
  }

  if (tport_tbind(self->sa_tports, tpn, tports, ta_tags(ta)) < 0) {
    error = su_errno();
    SU_DEBUG_1(("nta: bind(%s:%s;transport=%s%s%s%s%s): %s\n",
		tpn->tpn_canon, tpn->tpn_port, tpn->tpn_proto,
		tpn->tpn_canon != tpn->tpn_host ? ";maddr=" : "",
		tpn->tpn_canon != tpn->tpn_host ? tpn->tpn_host : "",
		tpn->tpn_comp ? ";comp=" : "",
		tpn->tpn_comp ? tpn->tpn_comp : "",
		su_strerror(error)));
    goto error;
  }
  else
    SU_DEBUG_5(("nta: bound to (%s:%s;transport=%s%s%s%s%s)\n",
		tpn->tpn_canon, tpn->tpn_port, tpn->tpn_proto,
		tpn->tpn_canon != tpn->tpn_host ? ";maddr=" : "",
		tpn->tpn_canon != tpn->tpn_host ? tpn->tpn_host : "",
		tpn->tpn_comp ? ";comp=" : "",
		tpn->tpn_comp ? tpn->tpn_comp : ""));

  /* XXX - when to use maddr? */
  if ((agent_init_via(self, tport_primaries(self->sa_tports), 0)) < 0) {
    error = su_errno();
    SU_DEBUG_1(("nta: cannot create Via headers\n"));
    goto error;
  }
  else
    SU_DEBUG_9(("nta: Via fields initialized\n"));

  if ((agent_init_contact(self)) < 0) {
    error = su_errno();
    SU_DEBUG_1(("nta: cannot create Contact header\n"));
    goto error;
  }
  else
    SU_DEBUG_9(("nta: Contact header created\n"));

  su_free(self->sa_home, url);
  ta_end(ta);

  return 0;

 error:
  ta_end(ta);
  su_seterrno(error);
  return -1;
}

static
int agent_create_master_transport(nta_agent_t *self, tagi_t *tags)
{
  self->sa_tports = 
    tport_tcreate(self, nta_agent_class, self->sa_root,
		  TPTAG_SDWN_ERROR(0),
		  TPTAG_IDLE(1800000),
		  TPTAG_DEBUG_DROP(self->sa_drop_prob),
		  TAG_NEXT(tags));

  if (!self->sa_tports)
    return -1;

  SU_DEBUG_9(("nta: master transport created\n"));

  return 0;
}


/** Initialize Via headers. */
static
int agent_init_via(nta_agent_t *self, tport_t *primaries, int use_maddr)
{
  sip_via_t *via = NULL, *new_via, *dup_via, *v, **vv = &via;
  sip_via_t *new_vias, **next_new_via, *new_publics, **next_new_public;
  tport_t *tp;
  su_addrinfo_t const *ai;

  su_home_t autohome[SU_HOME_AUTO_SIZE(2048)];

  su_home_auto(autohome, sizeof autohome);

  self->sa_tport_ip4 = 0;
  self->sa_tport_ip6 = 0;
  self->sa_tport_udp = 0;
  self->sa_tport_tcp = 0;
  self->sa_tport_sctp = 0;
  self->sa_tport_tls = 0;

  /* Set via fields for the tports */
  for (tp = primaries; tp; tp = tport_next(tp)) {
    int maddr, first_via;
    tp_name_t tpn[1];
    char const *comp = NULL;

    *tpn = *tport_name(tp);

    assert(tpn->tpn_proto);
    assert(tpn->tpn_canon);
    assert(tpn->tpn_host);
    assert(tpn->tpn_port);

#if 0
    if (getenv("SIP_UDP_CONNECT")
	&& strcmp(tpn->tpn_proto, "udp") == 0)
      tport_set_params(tp, TPTAG_CONNECT(1), TAG_END());
#endif

    if (tport_has_ip4(tp)) self->sa_tport_ip4 = 1;

#if SU_HAVE_IN6
    if (tport_has_ip6(tp)) self->sa_tport_ip6 = 1;
#endif

    if (strcasecmp(tpn->tpn_proto, "udp") == 0)
      self->sa_tport_udp = 1;
    else if (strcasecmp(tpn->tpn_proto, "tcp") == 0)
      self->sa_tport_tcp = 1;
    else if (strcasecmp(tpn->tpn_proto, "sctp") == 0)
      self->sa_tport_sctp = 1;

    if (tport_has_tls(tp)) self->sa_tport_tls = 1;

    first_via = 1;

    ai = tport_get_address(tp);

    for (; ai; ai = ai->ai_next) {
      char host[TPORT_HOSTPORTSIZE] = "";
      char sport[8];
      char const *canon = ai->ai_canonname;
      su_sockaddr_t *su = (void *)ai->ai_addr;
      int port;

      if (su) {
	inet_ntop(su->su_family, SU_ADDR(su), host, sizeof host);
	maddr = use_maddr && strcasecmp(canon, host) != 0;
	port = ntohs(su->su_port);
      }
      else {
	msg_random_token(host, 16, NULL, 0);
	canon = strcat(host, ".is.invalid");
	maddr = 0;
	port = 0;
      }
	
      if (strncasecmp(tpn->tpn_proto, "tls", 3)
	  ? port == SIP_DEFAULT_PORT
	  : port == SIPS_DEFAULT_PORT)
	port = 0;

      snprintf(sport, sizeof sport, ":%u", port);
      
      comp = tpn->tpn_comp;

      SU_DEBUG_9(("nta: agent_init_via: "
		  "%s/%s %s%s%s%s%s%s (%s)\n",
		  SIP_VERSION_CURRENT, tpn->tpn_proto,
		  canon, port ? sport : "",
		  maddr ? ";maddr=" : "", maddr ? host : "",
		  comp ? ";comp=" : "", comp ? comp : "",
		  tpn->tpn_ident ? tpn->tpn_ident : "*"));

      v = sip_via_format(autohome,
			 "%s/%s %s%s%s%s%s%s",
			 SIP_VERSION_CURRENT, tpn->tpn_proto,
			 canon, port ? sport : "",
			 maddr ? ";maddr=" : "", maddr ? host : "",
			 comp ? ";comp=" : "", comp ? comp : "");
      if (v == NULL)
	goto error;

      v->v_comment = tpn->tpn_ident;
      v->v_common->h_data = tp;	/* Nasty trick */
      *vv = v; vv = &(*vv)->v_next;
    }
  }

  /* Duplicate the list bind to the transports */
  new_via = sip_via_dup(self->sa_home, via);
  /* Duplicate the complete list shown to the application */
  dup_via = sip_via_dup(self->sa_home, via);

  if (via && (!new_via || !dup_via)) {
    msg_header_free(self->sa_home, (void *)new_via);
    msg_header_free(self->sa_home, (void *)dup_via);
    goto error;
  }

  new_vias = NULL, next_new_via = &new_vias;
  new_publics = NULL, next_new_public = &new_publics;

  /* Set via field magic for the tports */
  for (tp = primaries; tp; tp = tport_next(tp)) {
    assert(via->v_common->h_data == tp);
    v = tport_magic(tp);
    tport_set_magic(tp, new_via);
    msg_header_free(self->sa_home, (void *)v);

    if (tport_is_public(tp))
      *next_new_public = dup_via;
    else
      *next_new_via = dup_via;

    while (via->v_next && via->v_next->v_common->h_data == tp)
      via = via->v_next, new_via = new_via->v_next, dup_via = dup_via->v_next;
    
    via = via->v_next;
    /* Break the link in via list between transports */
    vv = &new_via->v_next, new_via = *vv, *vv = NULL;
    vv = &dup_via->v_next, dup_via = *vv, *vv = NULL;

    if (tport_is_public(tp))
      while (*next_new_public) next_new_public = &(*next_new_public)->v_next;
    else
      while (*next_new_via) next_new_via = &(*next_new_via)->v_next;
  }

  assert(dup_via == NULL);
  assert(new_via == NULL);

  if (self->sa_tport_udp)
    agent_set_udp_params(self, self->sa_udp_mtu);

  v = self->sa_vias;
  self->sa_vias = new_vias; 
  msg_header_free(self->sa_home, (void *)v);

  v = self->sa_public_vias;
  self->sa_public_vias = new_publics;
  msg_header_free(self->sa_home, (void *)v);

  su_home_deinit(autohome);

  return 0;

 error:
  su_home_deinit(autohome);
  return -1;
}


/** Initialize main contact header. */
static
int agent_init_contact(nta_agent_t *self)
{
  sip_via_t const *v1, *v2;
  char const *tp;

  if (self->sa_contact)
    return 0;

  if (self->sa_vias)
    v1 = self->sa_vias;
  else
    v1 = self->sa_public_vias;

  if (!v1)
    return -1;

  tp = strrchr(v1->v_protocol, '/');
  if (!tp++)
    return -1;

  v2 = v1->v_next;

  if (v2 && 
      strcasecmp(v1->v_host, v2->v_host) == 0 &&
      str0casecmp(v1->v_port, v2->v_port) == 0) {
    char const *p1 = v1->v_protocol, *p2 = v2->v_protocol;

    if (strcasecmp(p1, sip_transport_udp))
      p1 = v2->v_protocol, p2 = v1->v_protocol;

    if (strcasecmp(p1, sip_transport_udp) == 0 &&
	strcasecmp(p2, sip_transport_tcp) == 0)
      /* Do not include transport if we have both UDP and TCP */
      tp = NULL;
  }

  self->sa_contact = 
    sip_contact_create_from_via_with_transport(self->sa_home, v1, NULL, tp);

  if (!self->sa_contact)
    return -1;

  return 0;
}

/** Return Via line corresponging to tport. */