nta.c

this is simple sip stack.

static
sip_via_t const *agent_tport_via(tport_t *tport)
{
  sip_via_t *v = tport_magic(tport);
  while (v && v->v_next)
    v = v->v_next;
  return v;
}

/** Insert Via to a request message */
static
int outgoing_insert_via(nta_outgoing_t *orq, 
			sip_via_t const *via)
{
  nta_agent_t *self = orq->orq_agent;
  msg_t *msg = orq->orq_request;
  sip_t *sip = sip_object(msg);
  char const *branch = orq->orq_via_branch;
  int user_via = orq->orq_user_via;
  sip_via_t *v;
  int clear = 0;

  assert(sip); assert(via);

  if (user_via && sip->sip_via) {
    /* Use existing Via provided by application */
    v = sip->sip_via;
  }
  else if (msg && via && sip->sip_request &&
	   (v = sip_via_copy(msg_home(msg), via))) {
    msg_header_insert(msg, (msg_pub_t *)sip, (msg_header_t *)v);
  }
  else
    return -1;

  if (!v->v_rport && 
      ((self->sa_rport && v->v_protocol == sip_transport_udp) ||
       (self->sa_tcp_rport && v->v_protocol == sip_transport_tcp)))
    msg_header_add_param(msg_home(msg), v->v_common, "rport");

  if (!orq->orq_tpn->tpn_comp)
    msg_header_remove_param(v->v_common, "comp");

  if (branch && branch != v->v_branch) {
    char const *bvalue = branch + strcspn(branch, "=");
    if (*bvalue) bvalue++;
    if (!v->v_branch || strcasecmp(bvalue, v->v_branch))
      msg_header_replace_param(msg_home(msg), v->v_common, branch);
  }

  if (via->v_protocol != v->v_protocol &&
      strcasecmp(via->v_protocol, v->v_protocol))
    clear = 1, v->v_protocol = via->v_protocol;

  /* XXX - should we do this? */
  if (via->v_host != v->v_host &&
      str0cmp(via->v_host, v->v_host))
    clear = 1, v->v_host = via->v_host;

  if (via->v_port != v->v_port &&
      str0cmp(via->v_port, v->v_port))
    clear = 1, v->v_port = via->v_port;

  if (clear)
    msg_fragment_clear(v->v_common);

  return 0;
}

/** Get destination name from Via. 
 *
 * If @a using_rport is non-null, try rport.
 * If *using_rport is non-zero, try rport even if <protocol> is not UDP.
 * If <protocol> is UDP, set *using_rport to zero.
 */
static
int nta_tpn_by_via(tp_name_t *tpn, sip_via_t const *v, int *using_rport)
{
  if (!v)
    return -1;

  tpn->tpn_proto = sip_via_transport(v);
  tpn->tpn_canon = v->v_host;

  if (v->v_maddr)
    tpn->tpn_host = v->v_maddr;
  else if (v->v_received)
    tpn->tpn_host = v->v_received;
  else
    tpn->tpn_host = v->v_host;

  tpn->tpn_port = sip_via_port(v, using_rport);
  tpn->tpn_comp = v->v_comp;
  tpn->tpn_ident = NULL;

  return 0;
}

/** Get transport name from URL. */
int nta_tpn_by_url(su_home_t *home,
		   tp_name_t *tpn,
		   char const **scheme,
		   char const **port,
		   url_string_t const *us)
{
  url_t url[1];
  int n;
  char *b;

  n = url_xtra(us->us_url);
  b = su_alloc(home, n);

  if (b == NULL || url_dup(b, n, url, us->us_url) < 0) {
    su_free(home, b);
    return -1;
  }

  if (url->url_type != url_sip && 
      url->url_type != url_sips &&
      url->url_type != url_im &&
      url->url_type != url_pres) {
    su_free(home, b);
    return -1;
  }

  SU_DEBUG_7(("nta: selecting scheme %s\n", url->url_scheme));

  *scheme = url->url_scheme;
  if (strcasecmp(url->url_scheme, "sips") == 0)
    tpn->tpn_proto = "tls";
  else
    tpn->tpn_proto = "*";
  tpn->tpn_canon = url->url_host;
  tpn->tpn_host = url->url_host;

  if (url->url_params) {
    for (b = (char *)url->url_params; b[0]; b += n) {
      n = strcspn(b, ";");

      if (n > 10 && strncasecmp(b, "transport=", 10) == 0)
	tpn->tpn_proto = b + 10;
      else if (n > 5 && strncasecmp(b, "comp=", 5) == 0)
	tpn->tpn_comp = b + 5;
      else if (n > 6 && strncasecmp(b, "maddr=", 6) == 0)
	tpn->tpn_host = b + 6;

      if (b[n])
	b[n++] = '\0';
    }
  }

  if ((*port = url->url_port))
    tpn->tpn_port = url->url_port;

  tpn->tpn_ident = NULL;

  return 0;
}

/** Handle transport errors. */
static
void agent_tp_error(nta_agent_t *agent,
		    tport_t *tport,
		    int errcode,
		    char const *remote)
{
  su_llog(nta_log, 1,
	  "nta_agent: tport: %s%s%s\n",
	  remote ? remote : "", remote ? ": " : "",
	  su_strerror(errcode));
}

/** Handle updated transport addresses */
static void agent_update_tport(nta_agent_t *self, tport_t *tport)
{
  /* Initialize local Vias first */
  agent_init_via(self, tport_primaries(self->sa_tports), 0);

  if (self->sa_update_tport) {
    self->sa_update_tport(self->sa_update_magic, self);
  }
  else {
    /* XXX - we should do something else? */
    SU_DEBUG_3(("nta(%p): transport address updated\n", self));
  }
}

/* ====================================================================== */
/* 3) Message dispatch */

static void agent_recv_request(nta_agent_t *agent,
			       msg_t *msg,
			       sip_t *sip,
			       tport_t *tport);
static int agent_check_request_via(nta_agent_t *agent,
				   msg_t *msg,
				   sip_t *sip,
				   sip_via_t *v,
				   tport_t *tport);
static int agent_aliases(nta_agent_t const *, url_t [], tport_t *);
static void agent_recv_response(nta_agent_t*, msg_t *, sip_t *,
				sip_via_t *, tport_t*);
static void agent_recv_garbage(nta_agent_t*, msg_t*, tport_t*);


/** Handle incoming message. */
static
void agent_recv_message(nta_agent_t *agent,
			tport_t *tport,
			msg_t *msg,
			sip_via_t *tport_via,
			su_time_t now)
{
  sip_t *sip = sip_object(msg);

  agent->sa_millisec = su_time_ms(agent->sa_now = now);

  if (sip && sip->sip_request) {
    agent_recv_request(agent, msg, sip, tport);
  }
  else if (sip && sip->sip_status) {
    agent_recv_response(agent, msg, sip, tport_via, tport);
  }
  else {
    agent_recv_garbage(agent, msg, tport);
  }

  agent->sa_millisec = 0;
}

/** @internal Handle incoming requests. */
static
void agent_recv_request(nta_agent_t *agent,
			msg_t *msg,
			sip_t *sip,
			tport_t *tport)
{
  nta_leg_t *leg;
  nta_incoming_t *irq, *merge = NULL, *ack = NULL;
  sip_method_t method = sip->sip_request->rq_method;
  char const *method_name = sip->sip_request->rq_method_name;
  url_t url[1];
  unsigned cseq = sip->sip_cseq ? sip->sip_cseq->cs_seq : 0;
  int insane, errors, stream;

  agent->sa_stats->as_recv_msg++;
  agent->sa_stats->as_recv_request++;

  SU_DEBUG_5(("nta: received %s " URL_PRINT_FORMAT " %s (CSeq %u)\n",
	      method_name,
	      URL_PRINT_ARGS(sip->sip_request->rq_url),
	      sip->sip_request->rq_version, cseq));

  stream = tport_is_stream(tport);

  /* Try to use compression on reverse direction if Via has comp=sigcomp  */
  if (stream && 
      sip->sip_via->v_comp &&
      tport_can_send_sigcomp(tport) &&
      tport_name(tport)->tpn_comp == NULL && 
      tport_has_compression(tport_parent(tport), sip->sip_via->v_comp)) {
    tport_set_compression(tport, sip->sip_via->v_comp);
  }

  if (sip->sip_flags & MSG_FLG_TOOLARGE) {
    SU_DEBUG_5(("nta: %s (%u) is %s\n", 
		method_name, cseq, sip_413_Request_too_large));
    agent->sa_stats->as_bad_request++;
    nta_msg_treply(agent, msg, SIP_413_REQUEST_TOO_LARGE,
		   NTATAG_TPORT(tport),
		   NTATAG_INCOMPLETE(1),		   
		   TPTAG_SDWN_AFTER(stream),
		   TAG_END());
    return;
  }

  insane = 0;

  if (agent->sa_bad_req_mask)
    errors = msg_extract_errors(msg) & agent->sa_bad_req_mask;
  else
    errors = sip->sip_error != NULL;

  if (errors ||
      (sip->sip_flags & MSG_FLG_ERROR) /* Fatal error */ || 
      (insane = (sip_sanity_check(sip) < 0))) {
    sip_header_t const *h;
    char const *badname = NULL, *phrase;
    
    agent->sa_stats->as_bad_message++;
    agent->sa_stats->as_bad_request++;

    if (insane)
      SU_DEBUG_5(("nta: %s (%u) %s\n", method_name, cseq,
		  "failed sanity check"));

    for (h = (sip_header_t const *)sip->sip_error; h; h = h->sh_next) {
      char const *bad;

      if (h->sh_class == sip_error_class)
	bad = h->sh_error->er_name;
      else 
	bad = h->sh_class->hc_name;

      if (bad)
	SU_DEBUG_5(("nta: %s has bad %s header\n", method_name, bad));
      
      if (!badname)
	badname = bad;
    }

    if (sip->sip_via && method != sip_method_ack) {
      msg_t *reply = nta_msg_create(agent, 0);
      
      if (reply) {
	agent_check_request_via(agent, msg, sip, sip->sip_via, tport);

	if (badname)
	  phrase = su_sprintf(msg_home(reply), "Bad %s Header", badname);
	else
	  phrase = sip_400_Bad_request;

	SU_DEBUG_5(("nta: %s (%u) is %s\n", method_name, cseq, phrase));
	
	nta_msg_mreply(agent, reply, sip_object(reply),
		       400, phrase,
		       msg,
		       NTATAG_TPORT(tport), 
		       NTATAG_INCOMPLETE(1), 
		       TPTAG_SDWN_AFTER(stream),
		       TAG_END());
      }
    } else {
      msg_destroy(msg);
      if (stream)		/* Send FIN */
	tport_shutdown(tport, 1);
    }

    return;
  }

  if (str0casecmp(sip->sip_request->rq_version, sip_version_2_0) != 0) {
    agent->sa_stats->as_bad_request++;
    agent->sa_stats->as_bad_message++;

    SU_DEBUG_5(("nta: bad version %s for %s (%u)\n",
		sip->sip_request->rq_version, method_name, cseq));

    nta_msg_treply(agent, msg, SIP_505_VERSION_NOT_SUPPORTED,
		   NTATAG_TPORT(tport), 
		   TPTAG_SDWN_AFTER(stream),
		   TAG_END());

    return;
  }

  if (agent_check_request_via(agent, msg, sip, sip->sip_via, tport) < 0) {
    agent->sa_stats->as_bad_message++;
    agent->sa_stats->as_bad_request++;
    SU_DEBUG_5(("nta: %s (%u) %s\n", method_name, cseq, "has invalid Via"));
    msg_destroy(msg);
    return;
  }

  /* First, try existing incoming requests */
  irq = incoming_find(agent, sip, sip->sip_via, &merge, &ack);
  if (irq) {
    /* Match - this is a retransmission */
    SU_DEBUG_5(("nta: %s (%u) going to existing %s transaction\n",
		method_name, cseq, irq->irq_rq->rq_method_name));
    if (incoming_recv(irq, msg, sip, tport) >= 0)
      return;
  }
  else if (ack) {
    /* Match - this is an ACK or CANCEL or PRACK */
    SU_DEBUG_5(("nta: %s (%u) is going to %s (%u)\n",
		method_name, cseq,
		ack->irq_rq->rq_method_name, ack->irq_cseq->cs_seq));
    if (method == sip_method_ack) {
      if (incoming_ack(ack, msg, sip, tport) >= 0)
	return;
    }
    else if (method == sip_method_cancel) {
      if (incoming_cancel(ack, msg, sip, tport) >= 0)
	return;
    }
    else if (method == sip_method_prack) {
      if (reliable_recv(ack, msg, sip, tport) >= 0)
	return;
    }
    else {
      assert(!method);
    }
  }
  else if (merge) {
    SU_DEBUG_5(("nta: %s (%u) %s\n",
		method_name, cseq, "is a merged request"));
    if (incoming_merge(merge, msg, sip, tport) >= 0)
      return;
  }

  *url = *sip->sip_request->rq_url;
  url->url_params = NULL;
  agent_aliases(agent, url, tport); /* canonize urls */

  if ((leg = leg_find(agent, 
		      method_name, url, 
		      sip->sip_call_id,
		      sip->sip_from->a_tag, sip->sip_from->a_url, 
		      sip->sip_to->a_tag, sip->sip_to->a_url))) {
    /* Try existing dialog */
    SU_DEBUG_5(("nta: %s (%u) %s\n",
		method_name, cseq, "going to existing leg"));
    leg_recv(leg, msg, sip, tport);
    return;
  }
  else if (!agent->sa_is_stateless &&
	   (leg = dst_find(agent, url, method_name))) {
    /* Dialogless legs - let application process transactions statefully */
    SU_DEBUG_5(("nta: %s (%u) %s\n",
		method_name, cseq, "going to a dialogless leg"));
    leg_recv(leg, msg, sip, tport);
  }
  else if (!agent->sa_is_stateless && (leg = agent->sa_default_leg)) {
    SU_DEBUG_5(("nta: %s (%u) %s\n",
		method_name, cseq, "going to a default leg"));
    leg_recv(leg, msg, sip, tport);
  }
  else if (agent->sa_callback) {
    /* Stateless processing for request */
    agent->sa_stats->as_trless_request++;
    SU_DEBUG_5(("nta: %s (%u) %s\n", 
		method_name, cseq, "to message callback"));
    (void)agent->sa_callback(agent->sa_magic, agent, msg, sip);
  }
  else {
    agent->sa_stats->as_trless_request++;
    SU_DEBUG_5(("nta: %s (%u) no place to go: %d %s\n",
		method_name, cseq, SIP_501_NOT_IMPLEMENTED));
    if (method != sip