outbound.c

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

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2005 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

/**@CFILE outbound.c
 * @brief Implementation of SIP NAT traversal and outbound
 *
 * @author Pekka Pessi <[e-mail]>
 * @author Kai Vehmanen <[e-mail]>
 * @author Martti Mela <Martti [e-mail]>
 *
 * @date Created: Wed May 10 12:11:54 EEST 2006 ppessi
 */

#include "config.h"

#define NTA_OUTGOING_MAGIC_T struct outbound

#include "outbound.h"

#include <sofia-sip/hostdomain.h>
#include <sofia-sip/sip.h>
#include <sofia-sip/sip_protos.h>
#include <sofia-sip/sip_util.h>
#include <sofia-sip/sip_status.h>
#include <sofia-sip/su_tagarg.h>
#include <sofia-sip/tport.h>
#include <sofia-sip/nta_tport.h>

#include <sofia-sip/su_md5.h>
#include <sofia-sip/su_uniqueid.h>
#include <sofia-sip/token64.h>

#define SU_LOG (nua_log)
#include <sofia-sip/su_debug.h>

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>

struct outbound {
  su_home_t ob_home[1];
  outbound_owner_vtable
  const *ob_oo;			/**< Callbacks */
  outbound_owner_t *ob_owner;	/**< Backpointer */

  su_root_t *ob_root;		/**< Root for timers and stuff */
  nta_agent_t *ob_nta;		/**< SIP transactions */

  char ob_cookie[32];		/**< Our magic cookie */

  struct outbound_prefs {
    unsigned interval;	/**< Default keepalive interval for datagram */
    unsigned stream_interval;	/**< Default keepalive interval for streams */
    unsigned gruuize:1;		/**< Establish a GRUU */
    unsigned outbound:1;	/**< Try to use outbound */
    unsigned natify:1;		/**< Try to detect NAT */
    unsigned okeepalive:1;	/**< Connection keepalive with OPTIONS */
    unsigned validate:1;	/**< Validate registration with OPTIONS */
    /* How to detect NAT binding or connect to outbound: */
    unsigned use_connect:1;	/**< Use HTTP connect */
    unsigned use_rport:1;	/**< Use received/rport */
    unsigned use_socks:1;	/**< Detect and use SOCKS V5 */
    unsigned use_upnp:1;	/**< Detect and use UPnP */
    unsigned use_stun:1;	/**< Detect and try to use STUN */
    unsigned :0;
  } ob_prefs;

  struct outbound_info {
    /* See enum outbound_feature: */
    /* 0 do not support, 1 - perhaps supports, 2 - supports, 3 - requires */
    unsigned gruu:2, outbound:2, pref:2;
  } ob_info;

  /** Source of Contact header */
  unsigned ob_by_stack:1;
  /** Self-generated contacts */
  unsigned ob_contacts:1;

  /* The registration state machine. */
  /** Initial REGISTER containing ob_rcontact has been sent */
  unsigned ob_registering:1;
  /** 2XX response to REGISTER containg ob_rcontact has been received */
  unsigned ob_registered:1;
  /** The registration has been validated:
   *  We have successfully sent OPTIONS to ourselves.
   */
  unsigned ob_validated:1;
  /** The registration has been validated once.
   *   We have successfully sent OPTIONS to ourselves, so do not give
   *   up if OPTIONS probe fails.
   */
  unsigned ob_once_validated:1;

  unsigned ob_proxy_override:1;	/**< Override stack default proxy */
  unsigned :0;

  url_string_t *ob_proxy;	/**< Outbound-specific proxy */
  char const *ob_instance;	/**< Our instance ID */
  int32_t ob_reg_id;		/**< Flow-id */
  sip_contact_t *ob_rcontact;	/**< Our contact */
  sip_contact_t *ob_dcontact;	/**< Contact for dialogs */
  sip_contact_t *ob_previous;	/**< Stale contact */
  sip_contact_t *ob_gruu;	/**< Contact added to requests */
  sip_via_t *ob_via;		/**< Via header used to generate contacts */

  sip_contact_t *ob_obp;	/**< Contacts from outbound proxy */

  char *ob_nat_detected;	/**< Our public address */
  char *ob_nat_port;		/**< Our public port number */

  void *ob_stun;		/**< Stun context */
  void *ob_upnp;		/**< UPnP context  */

  struct {
    char *sipstun;		/**< Stun server usable for keep-alives */
    unsigned interval;		/**< Interval. */
    su_timer_t *timer;		/**< Keep-alive timer */
    msg_t *msg;			/**< Keep-alive OPTIONS message */
    nta_outgoing_t *orq;	/**< Keep-alive OPTIONS transaction */
    auth_client_t *auc[1];	/**< Authenticator for OPTIONS */
    /** Progress of registration validation */
    unsigned validating:1, validated:1,:0;
  } ob_keepalive;		/**< Keepalive informatio */
};

static
int outbound_nat_detect(outbound_t *ob,
       			 sip_t const *request,
       			 sip_t const *response);

/** Return values for outbound_nat_detect(). */
enum {
  ob_nat_error = -1,		/* or anything below zero */
  ob_no_nat = 0,
  ob_nat_detected = 1,
  ob_nat_changed = 2
};

/* ---------------------------------------------------------------------- */

#define SIP_METHOD_UNKNOWN sip_method_unknown, NULL

/** Content-Type sent in OPTIONS probing connectivity */
char const * const outbound_content_type = "application/vnd.nokia-register-usage";

static
int outbound_check_for_nat(outbound_t *ob,
			   sip_t const *request,
			   sip_t const *response);

enum outbound_feature {
  outbound_feature_unsupported = 0,
  outbound_feature_unsure = 1,
  outbound_feature_supported = 2,
  outbound_feature_required = 3
};

static enum outbound_feature feature_level(sip_t const *sip,
					   char const *tag, int level);

static int outbound_contacts_from_via(outbound_t *ob,
				      sip_via_t const *via);

/* ---------------------------------------------------------------------- */

/** Create a new outbound object */
outbound_t *
outbound_new(outbound_owner_t *owner,
	     outbound_owner_vtable const *owner_methods,
	     su_root_t *root,
	     nta_agent_t *agent,
	     char const *instance)
{
  outbound_t *ob;

  if (!owner || !owner_methods || !root || !agent)
    return NULL;

  ob = su_home_clone((su_home_t *)owner, sizeof *ob);
  
  if (ob) {
    su_md5_t md5[1];
    uint8_t digest[SU_MD5_DIGEST_SIZE];
    su_guid_t guid[1];

    ob->ob_owner = owner;
    ob->ob_oo = owner_methods;
    ob->ob_root = root;
    ob->ob_nta = agent;

    if (instance)
      ob->ob_instance =
	su_sprintf(ob->ob_home, "+sip.instance=\"<%s>\"", instance);
    ob->ob_reg_id = 0;

    /* Generate a random cookie (used as Call-ID) for us */
    su_md5_init(md5);
    su_guid_generate(guid);
    if (instance)
      su_md5_update(md5, (void *)instance, strlen(instance));
    su_md5_update(md5, (void *)guid, sizeof guid);
    su_md5_digest(md5, digest);
    token64_e(ob->ob_cookie, sizeof ob->ob_cookie, digest, sizeof digest);
    
    if (instance && !ob->ob_instance)
      su_home_unref(ob->ob_home), ob = NULL;
  }

  return ob;
}

void outbound_unref(outbound_t *ob)
{
  if (ob->ob_keepalive.timer)
    su_timer_destroy(ob->ob_keepalive.timer), ob->ob_keepalive.timer = NULL;

  if (ob->ob_keepalive.orq)
    nta_outgoing_destroy(ob->ob_keepalive.orq), ob->ob_keepalive.orq = NULL;

  if (ob->ob_keepalive.msg)
    msg_destroy(ob->ob_keepalive.msg), ob->ob_keepalive.msg = NULL;

  su_home_unref(ob->ob_home);
}

#include <sofia-sip/bnf.h>

/** Set various outbound and nat-traversal related options. */
int outbound_set_options(outbound_t *ob,
			 char const *_options,
			 unsigned interval,
			 unsigned stream_interval)
{
  struct outbound_prefs prefs[1] = {{ 0 }};
  char *s, *options = su_strdup(NULL, _options);
  int invalid;

  prefs->interval = interval;
  prefs->stream_interval = stream_interval;

#define MATCH(v) (len == sizeof(#v) - 1 && strncasecmp(#v, s, len) == 0)

  if (options) {
    for (s = options; s[0]; s++) if (s[0] == '-') s[0] = '_';
  }

  prefs->gruuize = 1;
  prefs->outbound = 0;
  prefs->natify = 1;
  prefs->okeepalive = 1;
  prefs->validate = 1;
  prefs->use_rport = 1;

  for (s = options; s && s[0]; ) {
    size_t len = span_token(s);
    int value = 1;

    if (len > 3 && strncasecmp(s, "no_", 3) == 0)
      value = 0, s += 3, len -= 3;
    else if (len > 4 && strncasecmp(s, "not_", 4) == 0)
      value = 0, s += 4, len -= 4;

    if (len == 0)
      break;
    else if (MATCH(gruuize)) prefs->gruuize = value;
    else if (MATCH(outbound)) prefs->outbound = value;
    else if (MATCH(natify)) prefs->natify = value;
    else if (MATCH(validate)) prefs->validate = value;
    else if (MATCH(options_keepalive)) prefs->okeepalive = value;
    else if (MATCH(use_connect)) prefs->use_connect = value;
    else if (MATCH(use_rport)) prefs->use_rport = value;
    else if (MATCH(use_socks)) prefs->use_socks = value;
    else if (MATCH(use_upnp)) prefs->use_upnp = value;
    else if (MATCH(use_stun)) prefs->use_stun = value;
    else
      SU_DEBUG_1(("outbound(%p): unknown option \"%.*s\"\n",
		  (void *)ob->ob_owner, (int)len, s));

    s += len;
    len = strspn(s, " \t\n\r,;");
    if (len == 0)
      break;
    s += len;
  }

  invalid = s && s[0];
  su_free(NULL, options);

  if (invalid) {
    SU_DEBUG_1(("outbound(%p): invalid options \"%s\"\n", 
		(void *)ob->ob_owner, options));
    return -1;
  }

  if (prefs->natify &&
      !(prefs->outbound ||
	prefs->use_connect ||
	prefs->use_rport ||
	prefs->use_socks ||
	prefs->use_upnp ||
	prefs->use_stun)) {
    SU_DEBUG_1(("outbound(%p): no nat traversal method given\n",
		(void *)ob->ob_owner));
  }

  ob->ob_prefs = *prefs;
  ob->ob_reg_id = prefs->outbound ? 1 : 0;

  return 0;
}

/** Override stack default proxy for outbound */
int outbound_set_proxy(outbound_t *ob,
		       url_string_t *proxy)
{
  url_string_t *new_proxy = NULL, *old_proxy = ob->ob_proxy;

  if (proxy)
    new_proxy = (url_string_t *)url_as_string(ob->ob_home, proxy->us_url);

  if (proxy == NULL || new_proxy != NULL) {
    ob->ob_proxy_override = 1;
    ob->ob_proxy = new_proxy;
    su_free(ob->ob_home, old_proxy);
    return 0;
  }

  return -1;
}

/* ---------------------------------------------------------------------- */

/** Obtain contacts for REGISTER */
int outbound_get_contacts(outbound_t *ob, 
			  sip_contact_t **return_current_contact, 
			  sip_contact_t **return_previous_contact)
{
  if (ob) {
    if (ob->ob_contacts)
      *return_current_contact = ob->ob_rcontact;
    else {
      sip_contact_t *contact = *return_current_contact;
      if (contact) {
	if (ob->ob_rcontact)
	  msg_header_free_all(ob->ob_home, (msg_header_t*)ob->ob_rcontact);
	ob->ob_rcontact = sip_contact_dup(ob->ob_home, contact);
      }
    }
    *return_previous_contact = ob->ob_previous;
  }
  return 0;
}

/** REGISTER request has been sent */
int outbound_start_registering(outbound_t *ob)
{
  if (ob)
    ob->ob_registering = 1;
  return 0;
}

/** Process response to REGISTER request */
int outbound_register_response(outbound_t *ob,
			       int terminating,
			       sip_t const *request,
			       sip_t const *response)
{
  int status, reregister;

  if (!ob)
    return 0;

  if (terminating) {
    ob->ob_registering = ob->ob_registered = 0;
    return 0;			/* Cleanup is done separately */
  }  

  if (!response || !request)
    return 0;

  assert(request->sip_request); assert(response->sip_status);
  
  reregister = outbound_check_for_nat(ob, request, response);
  if (reregister)
    return reregister;

  status = response->sip_status->st_status;

  if (status < 300) {
    if (request->sip_contact && response->sip_contact)
      ob->ob_registered = ob->ob_registering;
    else
      ob->ob_registered = 0;

    if (ob->ob_previous)
      msg_header_free(ob->ob_home, (void *)ob->ob_previous);
    ob->ob_previous = NULL;
  }