chan_sip.c

static void parse_copy(struct sip_request *dst, const struct sip_request *src)
{
	memset(dst, 0, sizeof(*dst));
	memcpy(dst->data, src->data, sizeof(dst->data));
	dst->len = src->len;
	parse_request(dst);
}

/*! \brief add a blank line if no body */
static void add_blank(struct sip_request *req)
{
	if (!req->lines) {
		/* Add extra empty return. add_header() reserves 4 bytes so cannot be truncated */
		ast_copy_string(req->data + req->len, "\r\n", sizeof(req->data) - req->len);
		req->len += strlen(req->data + req->len);
	}
}

/*! \brief Transmit response on SIP request*/
static int send_response(struct sip_pvt *p, struct sip_request *req, enum xmittype reliable, int seqno)
{
	int res;

	add_blank(req);
	if (sip_debug_test_pvt(p)) {
		const struct sockaddr_in *dst = sip_real_dst(p);

		ast_verbose("\n<--- %sTransmitting (%s) to %s:%d --->\n%s\n<------------>\n",
			reliable ? "Reliably " : "", sip_nat_mode(p),
			ast_inet_ntoa(dst->sin_addr),
			ntohs(dst->sin_port), req->data);
	}
	if (p->do_history) {
		struct sip_request tmp;
		parse_copy(&tmp, req);
		append_history(p, reliable ? "TxRespRel" : "TxResp", "%s / %s - %s", tmp.data, get_header(&tmp, "CSeq"), 
			(tmp.method == SIP_RESPONSE || tmp.method == SIP_UNKNOWN) ? tmp.rlPart2 : sip_methods[tmp.method].text);
	}
	res = (reliable) ?
		 __sip_reliable_xmit(p, seqno, 1, req->data, req->len, (reliable == XMIT_CRITICAL), req->method) :
		__sip_xmit(p, req->data, req->len);
	if (res > 0)
		return 0;
	return res;
}

/*! \brief Send SIP Request to the other part of the dialogue */
static int send_request(struct sip_pvt *p, struct sip_request *req, enum xmittype reliable, int seqno)
{
	int res;

	/* If we have an outbound proxy, reset peer address 
		Only do this once.
	*/
	if (p->outboundproxy) {
		p->sa = p->outboundproxy->ip;
	}

	add_blank(req);
	if (sip_debug_test_pvt(p)) {
		if (ast_test_flag(&p->flags[0], SIP_NAT_ROUTE))
			ast_verbose("%sTransmitting (NAT) to %s:%d:\n%s\n---\n", reliable ? "Reliably " : "", ast_inet_ntoa(p->recv.sin_addr), ntohs(p->recv.sin_port), req->data);
		else
			ast_verbose("%sTransmitting (no NAT) to %s:%d:\n%s\n---\n", reliable ? "Reliably " : "", ast_inet_ntoa(p->sa.sin_addr), ntohs(p->sa.sin_port), req->data);
	}
	if (p->do_history) {
		struct sip_request tmp;
		parse_copy(&tmp, req);
		append_history(p, reliable ? "TxReqRel" : "TxReq", "%s / %s - %s", tmp.data, get_header(&tmp, "CSeq"), sip_methods[tmp.method].text);
	}
	res = (reliable) ?
		__sip_reliable_xmit(p, seqno, 0, req->data, req->len, (reliable == XMIT_CRITICAL), req->method) :
		__sip_xmit(p, req->data, req->len);
	return res;
}

/*! \brief Locate closing quote in a string, skipping escaped quotes.
 * optionally with a limit on the search.
 * start must be past the first quote.
 */
static const char *find_closing_quote(const char *start, const char *lim)
{
	char last_char = '\0';
	const char *s;
	for (s = start; *s && s != lim; last_char = *s++) {
		if (*s == '"' && last_char != '\\')
			break;
	}
	return s;
}

/*! \brief Pick out text in brackets from character string
	\return pointer to terminated stripped string
	\param tmp input string that will be modified
	Examples:
\verbatim
	"foo" <bar>	valid input, returns bar
	foo		returns the whole string
	< "foo ... >	returns the string between brackets
	< "foo...	bogus (missing closing bracket), returns the whole string
			XXX maybe should still skip the opening bracket
\endverbatim
 */
static char *get_in_brackets(char *tmp)
{
	const char *parse = tmp;
	char *first_bracket;

	/*
	 * Skip any quoted text until we find the part in brackets.
	* On any error give up and return the full string.
	*/
	while ( (first_bracket = strchr(parse, '<')) ) {
		char *first_quote = strchr(parse, '"');

		if (!first_quote || first_quote > first_bracket)
			break; /* no need to look at quoted part */
		/* the bracket is within quotes, so ignore it */
		parse = find_closing_quote(first_quote + 1, NULL);
		if (!*parse) { /* not found, return full string ? */
			/* XXX or be robust and return in-bracket part ? */
			ast_log(LOG_WARNING, "No closing quote found in '%s'\n", tmp);
			break;
		}
		parse++;
	}
	if (first_bracket) {
		char *second_bracket = strchr(first_bracket + 1, '>');
		if (second_bracket) {
			*second_bracket = '\0';
			tmp = first_bracket + 1;
		} else {
			ast_log(LOG_WARNING, "No closing bracket found in '%s'\n", tmp);
		}
	}
	
	return tmp;
}

/*! \brief * parses a URI in its components.
 *
 * \note 
 * - If scheme is specified, drop it from the top.
 * - If a component is not requested, do not split around it.
 *
 * This means that if we don't have domain, we cannot split
 * name:pass and domain:port.
 * It is safe to call with ret_name, pass, domain, port
 * pointing all to the same place.
 * Init pointers to empty string so we never get NULL dereferencing.
 * Overwrites the string.
 * return 0 on success, other values on error.
 * \verbatim 
 * general form we are expecting is sip[s]:username[:password][;parameter]@host[:port][;...] 
 * \endverbatim
 */
static int parse_uri(char *uri, char *scheme,
	char **ret_name, char **pass, char **domain, char **port, char **options)
{
	char *name = NULL;
	int error = 0;

	/* init field as required */
	if (pass)
		*pass = "";
	if (port)
		*port = "";
	if (scheme) {
		int l = strlen(scheme);
		if (!strncasecmp(uri, scheme, l))
			uri += l;
		else {
			ast_debug(1, "Missing scheme '%s' in '%s'\n", scheme, uri);
			error = -1;
		}
	}
	if (!domain) {
		/* if we don't want to split around domain, keep everything as a name,
		 * so we need to do nothing here, except remember why.
		 */
	} else {
		/* store the result in a temp. variable to avoid it being
		 * overwritten if arguments point to the same place.
		 */
		char *c, *dom = "";

		if ((c = strchr(uri, '@')) == NULL) {
			/* domain-only URI, according to the SIP RFC. */
			dom = uri;
			name = "";
		} else {
			*c++ = '\0';
			dom = c;
			name = uri;
		}

		/* Remove options in domain and name */
		dom = strsep(&dom, ";");
		name = strsep(&name, ";");

		if (port && (c = strchr(dom, ':'))) { /* Remove :port */
			*c++ = '\0';
			*port = c;
		}
		if (pass && (c = strchr(name, ':'))) {	/* user:password */
			*c++ = '\0';
			*pass = c;
		}
		*domain = dom;
	}
	if (ret_name)	/* same as for domain, store the result only at the end */
		*ret_name = name;
	if (options)
		*options = uri ? uri : "";

	return error;
}

/*! \brief Send message with Access-URL header, if this is an HTML URL only! */
static int sip_sendhtml(struct ast_channel *chan, int subclass, const char *data, int datalen)
{
	struct sip_pvt *p = chan->tech_pvt;

	if (subclass != AST_HTML_URL)
		return -1;

	ast_string_field_build(p, url, "<%s>;mode=active", data);

	if (sip_debug_test_pvt(p))
		ast_debug(1, "Send URL %s, state = %d!\n", data, chan->_state);

	switch (chan->_state) {
	case AST_STATE_RING:
		transmit_response(p, "100 Trying", &p->initreq);
		break;
	case AST_STATE_RINGING:
		transmit_response(p, "180 Ringing", &p->initreq);
		break;
	case AST_STATE_UP:
		if (!p->pendinginvite) {		/* We are up, and have no outstanding invite */
			transmit_reinvite_with_sdp(p, FALSE, FALSE);
		} else if (!ast_test_flag(&p->flags[0], SIP_PENDINGBYE)) {
			ast_set_flag(&p->flags[0], SIP_NEEDREINVITE);	
		}	
		break;
	default:
		ast_log(LOG_WARNING, "Don't know how to send URI when state is %d!\n", chan->_state);
	}

	return 0;
}

/*! \brief Deliver SIP call ID for the call */
static char *sip_get_callid(struct ast_channel *chan)
{
	struct sip_pvt *p = chan->tech_pvt;
	if (!p)
		return "";
	return ((char *)p->callid);
}

/*! \brief Send SIP MESSAGE text within a call
	Called from PBX core sendtext() application */
static int sip_sendtext(struct ast_channel *ast, const char *text)
{
	struct sip_pvt *p = ast->tech_pvt;
	int debug = sip_debug_test_pvt(p);

	if (debug)
		ast_verbose("Sending text %s on %s\n", text, ast->name);
	if (!p)
		return -1;
	if (ast_strlen_zero(text))
		return 0;
	if (debug)
		ast_verbose("Really sending text %s on %s\n", text, ast->name);
	transmit_message_with_text(p, text);
	return 0;	
}

/*! \brief Update peer object in realtime storage 
	If the Asterisk system name is set in asterisk.conf, we will use
	that name and store that in the "regserver" field in the sippeers
	table to facilitate multi-server setups.
*/
static void realtime_update_peer(const char *peername, struct sockaddr_in *sin, const char *defaultuser, const char *fullcontact, int expirey)
{
	char port[10];
	char ipaddr[INET_ADDRSTRLEN];
	char regseconds[20];
	char *tablename = NULL;

	const char *sysname = ast_config_AST_SYSTEM_NAME;
	char *syslabel = NULL;

	time_t nowtime = time(NULL) + expirey;
	const char *fc = fullcontact ? "fullcontact" : NULL;

	int realtimeregs = ast_check_realtime("sipregs");

	tablename = realtimeregs ? "sipregs" : "sippeers";
	
	snprintf(regseconds, sizeof(regseconds), "%d", (int)nowtime);	/* Expiration time */
	ast_copy_string(ipaddr, ast_inet_ntoa(sin->sin_addr), sizeof(ipaddr));
	snprintf(port, sizeof(port), "%d", ntohs(sin->sin_port));
	
	if (ast_strlen_zero(sysname))	/* No system name, disable this */
		sysname = NULL;
	else if (sip_cfg.rtsave_sysname)
		syslabel = "regserver";

	if (fc)
		ast_update_realtime(tablename, "name", peername, "ipaddr", ipaddr,
			"port", port, "regseconds", regseconds,
			"defaultuser", defaultuser, fc, fullcontact, syslabel, sysname, NULL); /* note fc and syslabel _can_ be NULL */
	else
		ast_update_realtime(tablename, "name", peername, "ipaddr", ipaddr,
			"port", port, "regseconds", regseconds,
			"defaultuser", defaultuser, syslabel, sysname, NULL); /* note syslabel _can_ be NULL */
}

/*! \brief Automatically add peer extension to dial plan */
static void register_peer_exten(struct sip_peer *peer, int onoff)
{
	char multi[256];
	char *stringp, *ext, *context;

	/* XXX note that global_regcontext is both a global 'enable' flag and
	 * the name of the global regexten context, if not specified
	 * individually.
	 */
	if (ast_strlen_zero(global_regcontext))
		return;

	ast_copy_string(multi, S_OR(peer->regexten, peer->name), sizeof(multi));
	stringp = multi;
	while ((ext = strsep(&stringp, "&"))) {
		if ((context = strchr(ext, '@'))) {
			*context++ = '\0';	/* split ext@context */
			if (!ast_context_find(context)) {
				ast_log(LOG_WARNING, "Context %s must exist in regcontext= in sip.conf!\n", context);
				continue;
			}
		} else {
			context = global_regcontext;
		}
		if (onoff)
			ast_add_extension(context, 1, ext, 1, NULL, NULL, "Noop",
				 ast_strdup(peer->name), ast_free_ptr, "SIP");
		else
			ast_context_remove_extension(context, ext, 1, NULL);
	}
}

/*! Destroy mailbox subscriptions */
static void destroy_mailbox(struct sip_mailbox *mailbox)
{
	if (mailbox->mailbox)
		ast_free(mailbox->mailbox);
	if (mailbox->context)
		ast_free(mailbox->context);
	if (mailbox->event_sub)
		ast_event_unsubscribe(mailbox->event_sub);
	ast_free(mailbox);
}

/*! Destroy all peer-related mailbox subscriptions */
static void clear_peer_mailboxes(struct sip_peer *peer)
{
	struct sip_mailbox *mailbox;

	while ((mailbox = AST_LIST_REMOVE_HEAD(&peer->mailboxes, entry)))
		destroy_mailbox(mailbox);
}

/*! \brief Destroy peer object from memory */
static void sip_destroy_peer(struct sip_peer *peer)
{
	ast_debug(3, "Destroying SIP peer %s\n", peer->name);

	if (peer->outboundproxy)
		ast_free(peer->outboundproxy);
	peer->outboundproxy = NULL;

	/* Delete it, it needs to disappear */
	if (peer->call)
		peer->call = sip_destroy(peer->call);

	if (peer->mwipvt) 	/* We have an active subscription, delete it */
		peer->mwipvt = sip_destroy(peer->mwipvt);

	if (peer->chanvars) {
		ast_variables_destroy(peer->chanvars);
		peer->chanvars = NULL;
	}

	/* If the schedule delete fails, that means the schedule is currently
	 * running, which means we should wait for that thread to complete.
	 * Otherwise, there's a crashable race condition.
	 *
	 * NOTE: once peer is refcounted, this probably is no longer necessary.
	 */
	while (peer->expire > -1 && ast_sched_del(sched, peer->expire))
		usleep(1);
	while (peer->pokeexpire > -1 && ast_sched_del(sched, peer->pokeexpire))
		usleep(1);

	register_peer_exten(peer, FALSE);
	ast_free_ha(peer->ha);
	if (peer->selfdestruct)
		apeerobjs--;
	else if (peer->is_realtime) {
		rpeerobjs--;
		ast_debug(3,"-REALTIME- peer Destroyed. Name: %s. Realtime Peer objects: %d\n", peer->name, rpeerobjs);
	} else
		speerobjs--;
	clear_realm_authentication(peer->auth);
	peer->auth = NULL;
	if (peer->dnsmgr)
		ast_dnsmgr_release(peer->dnsmgr);
	clear_peer_mailboxes(peer);
	ast_free(peer);
}

/*! \brief Update peer data in database (if used) */
static void update_peer(struct sip_peer *p, int expiry)
{
	int rtcachefriends = ast_test_flag(&p->flags[1], SIP_PAGE2_RTCACHEFRIENDS);
	if (sip_cfg.peer_rtupdate &&
	    (p->is_realtime || rtcachefriends)) {
		realtime_update_peer(p->name, &p->addr, p->username, rtcachefriends ? p->fullcontact : NULL, expiry);
	}
}

static struct ast_variable *get_insecure_variable_from_config(struct ast_config *config)
{
	struct ast_variable *var = NULL;
	struct ast_flags flags = {0};
	char *cat = NULL;
	const char *insecure;
	while ((cat = ast_category_browse(config, cat))) {
		insecure = ast_variable_retrieve(config, cat, "insecure");
		set_insecure_flags(&flags, insecure, -1);
		if (ast_test_flag(&flags, SIP_INSECURE_PORT)) {
			var = ast_category_root(config, cat);
			break;
		}
	}
	return var;
}

static const char *get_name_from_variable(struct ast_variable *var, const char *newpeername)
{
	struct ast_variable *tmp;
	for (tmp = var; tmp; tmp = tmp->next) {
		if (!newpeername && !strcasecmp(tmp->name, "name"))
			newpeername = tmp->value;
	}
	return newpeername;
}

/*! \brief  realtime_peer: Get peer from realtime storage
 * Checks the "sippeers" realtime family from extconfig.conf 
 * Checks the "sipregs" realtime family from extconfig.conf if it's configured.
*/
static struct sip_peer *realtime_peer(const char *newpeername, struct sockaddr_in *sin)
{
	struct sip_peer *peer;
	struct ast_variable *var = NULL;
	struct ast_variable *varregs = NULL;
	struct ast_variable *tmp;
	struct ast_config *peerlist = NULL;
	char ipaddr[INET_ADDRSTRLEN];
	char portstring[6]; /*up to 5 digits plus null terminator*/
	char *cat = NULL;
	unsigned short portnum;
	int realtimeregs = ast_check_realtime("sipregs");

	/* First check on peer name */
	if (newpeername) {
		if (realtimeregs)
			varregs = ast_load_realtime("sipregs", "name", newpeername, NULL);

		var = ast_load_realtime("sippeers", "name", newpeername, "host", "dynamic", NULL);
		if (!var && sin)
			var = ast_load_realtime("sippeers", "name", newpeername, "host", ast_inet_ntoa(sin->sin_addr), NULL);
		if (!var) {
			var = ast_load_realtime("sippeers", "name", newpeername, NULL);
			/*!\note
			 * If this one loaded something, then we need to ensure that the host
			 * field matched.  The only reason why we can't have this as a criteria
			 * is because we only have the IP address and the host field might be
			 * set as a name (and the reverse PTR might not match).
			 */
			if (var) {
				for (tmp = var; tmp; tmp = tmp->next) {
					if (!strcasecmp(var->name, "host")) {
						struct in_addr sin2 = { 0, };
						struct ast_dnsmgr_entry *dnsmgr = NULL;
						if ((ast_dnsmgr_lookup(tmp->value, &sin2, &dnsmgr) < 0) || (memcmp(&sin2, &sin->sin_addr, sizeof(sin2)) != 0)) {
							/* No match */
							ast_variables_destroy(var);
							var = NULL;
						}
						break;
					}
				}
			}
		}
	}

	if (!var && sin) {	/* Then check on IP address for dynamic peers */
		ast_copy_string(ipaddr, ast_inet_ntoa(sin->sin_addr), sizeof(ipaddr));
		portnum = ntohs(sin->sin_port);
		sprintf(portstring, "%u", portnum);
		var = ast_load_realtime("sippeers", "host", ipaddr, "port", portstring, NULL);	/* First check for fixed IP hosts */
		if (var) {
			if (realtimeregs) {
				newpeername = get_name_from_variable(var, newpeername);
				varregs = ast_load_realtime("sipregs", "name", newpeername, NULL);
			}
		} else {
			if (realtimeregs)
				varregs = ast_load_realtime("sipregs", "ipaddr", ipaddr, "port", portstring, NULL); /* Then check for registered hosts */
			else
				var = ast_load_realtime("sippeers", "ipaddr", ipaddr, "port", portstring, NULL); /* Then check for registered hosts */
			if (varregs) {
				newpeername = get_name_from_variable(varregs, newpeername);
				var = ast_load_realtime("sippeers", "name", newpeername, NULL);
			}
		}
		if (!var) { /*We couldn't match on ipaddress and port, so we need to check if port is insecure*/
			peerlist = ast_load_realtime_multientry("sippeers", "host", ipaddr, NULL);
			if (peerlist) {
				var = get_insecure_variable_from_config(peerlist);
				if(var) {
					if (realtimeregs) {
						newpeername = get_name_from_variable(var, newpeername);
						varregs = ast_load_realtime("sipregs", "name", newpeername, NULL);
					}
				} else { /*var wasn't found in the list of "hosts", so try "ipaddr"*/
					peerlist = NULL;
					cat = NULL;
					peerlist = ast_load_realtime_multientry("sippeers", "ipaddr", ipaddr, NULL);
					if(peerlist) {
						var = get_insecure_variable_from_config(peerlist);
						if(var) {
							if (realtimeregs) {
								newpeername = get_name_from_variable(var, newpeername);
								varregs = ast_load_realtime("sipregs", "name", newpeername, NULL);
							}
						}
					}
				}
			} else {
				if (realtimeregs) {
					peerlist = ast_load_realtime_multientry("sipregs", "ipaddr", ipaddr, NULL);
					if (peerlist) {
						varregs = get_insecure_variable_from_config(peerlist);
						if (varregs) {
							newpeername = get_name_from_variable(varregs, newpeername);
							var = ast_load_realtime("sippeers", "name", newpeername, NULL);
						}
					}
				} else {
					peerlist = ast_load_realtime_multientry("sippeers", "ipaddr", ipaddr, NULL);
					if (peerlist) {
						var = get_insecure_variable_from_config(peerlist);
						if (var) {
							newpeername = get_name_from_variable(var, newpeername);
							varregs = ast_load_realtime("sipregs", "name", newpeername, NULL);
						}
					}
				}
			}
		}
	}

	if (!var) {
		if (peerlist)
			ast_config_destroy(peerlist);
		return NULL;
	}

	for (tmp = var; tmp; tmp = tmp->next) {
		/* If this is type=user, then skip this object. */
		if (!strcasecmp(tmp->name, "type") &&
		    !strcasecmp(tmp->value, "user")) {
			if(peerlist)
				ast_config_destroy(peerlist);
			else {
				ast_variables_destroy(var);
				ast_variables_destroy(varregs);
			}
			return NULL;
		} else if (!newpeername && !strcasecmp(tmp->name, "name")) {
			newpeername = tmp->value;
		}
	}
	
	if (!newpeername) {	/* Did not find peer in realtime */
		ast_log(LOG_WARNING, "Cannot Determine peer name ip=%s\n", ipaddr);
		if(peerlist)
			ast_config_destroy(peerlist);
		else
			ast_variables_destroy(var);
		return NULL;
	}


	/* Peer found in realtime, now build it in memory */
	peer = build_peer(newpeername, var, varregs, !ast_test_flag(&global_flags[1], SIP_PAGE2_RTCACHEFRIENDS));
	if (!peer) {
		if(peerlist)
			ast_config_destroy(peerlist);
		else {
			ast_variables_destroy(var);
			ast_variables_destroy(varregs);
		}
		return NULL;
	}

	ast_debug(3,"-REALTIME- loading peer from database to memory. Name: %s. Peer objects: %d\n", peer->name, rpeerobjs);

	if (ast_test_flag(&global_flags[1], SIP_PAGE2_RTCACHEFRIENDS)) {
		/* Cache peer */
		ast_copy_flags(&peer->flags[1],&global_flags[1], SIP_PAGE2_RTAUTOCLEAR|SIP_PAGE2_RTCACHEFRIENDS);
		if (ast_test_flag(&global_flags[1], SIP_PAGE2_RTAUTOCLEAR)) {
			peer->expire = ast_sched_replace(peer->expire, sched, 
				global_rtautoclear * 1000, expire_register, (void *) peer);
		}
		ASTOBJ_CONTAINER_LINK(&peerl,peer);
	} else {
		peer->is_realtime = 1;
	}
	if (peerlist)
		ast_config_destroy(peerlist);
	else {
		ast_variables_destroy(var);
		ast_variables_destroy(varregs);
	}

	return peer;
}

/*! \brief Support routine for find_peer */
static int sip_addrcmp(char *name, struct sockaddr_in *sin)
{
	/* We know name is the first field, so we can cast */
	struct sip_peer *p = (struct sip_peer *) name;
	return 	!(!inaddrcmp(&p->addr, sin) || 
					(ast_test_flag(&p->flags[0], SIP_INSECURE_PORT) &&
					(p->addr.sin_addr.s_addr == sin->sin_addr.s_addr)));
}

/*! \brief Locate peer by name or ip address 
 *	This is used on incoming SIP message to find matching peer on ip
	or outgoing message to find matching peer on name 
	\note Avoid using this function in new functions if there's a way to avoid it, i
	since it causes a database lookup or a traversal of the in-memory peer list.
*/
static struct sip_peer *find_peer(const char *peer, struct sockaddr_in *sin, int realtime)
{
	struct sip_peer *p = NULL;

	if (peer)
		p = ASTOBJ_CONTAINER_FIND(&peerl, peer);
	else
		p = ASTOBJ_CONTAINER_FIND_FULL(&peerl, sin, name, sip_addr_hashfunc, 1, sip_addrcmp);

	if (!p && realtime)
		p = realtime_peer(peer, sin);

	return p;
}

/*! \brief Remove user object from in-memory storage */
static void sip_destroy_user(struct sip_user *user)
{
	ast_debug(3, "Destroying user object from memory: %s\n", user->name);

	ast_free_ha(user->ha);
	if (user->chanvars) {
		ast_variables_destroy(user->chanvars);
		user->chanvars = NULL;
	}
	if (user->is_realtime)
		ruserobjs--;
	else
		suserobjs--;
	ast_free(user);
}

/*! \brief Load user from realtime storage
 * Loads user from "sipusers" category in realtime (extconfig.conf)
 * Users are matched on From: user name (the domain in skipped) */
static struct sip_user *realtime_user(const char *username)
{
	struct ast_variable *var;
	struct ast_variable *tmp;
	struct sip_user *user = NULL;

	var = ast_load_realtime("sipusers", "name", username, NULL);

	if (!var)
		return NULL;

	for (tmp = var; tmp; tmp = tmp->next) {
		if (!strcasecmp(tmp->name, "type") &&
			!strcasecmp(tmp->value, "peer")) {
			ast_variables_destroy(var);
			return NULL;
		}
	}

	user = build_user(username, var, !ast_test_flag(&global_flags[1], SIP_PAGE2_RTCACHEFRIENDS));
	
	if (!user) {	/* No user found */
		ast_variables_destroy(var);
		return NULL;
	}

	if (ast_test_flag(&global_flags[1], SIP_PAGE2_RTCACHEFRIENDS)) {
		ast_set_flag(&user->flags[1], SIP_PAGE2_RTCACHEFRIENDS);
		suserobjs++;
		ASTOBJ_CONTAINER_LINK(&userl,user);
	} else {
		/* Move counter from s to r... */
		suserobjs--;
		ruserobjs++;
		user->is_realtime = 1;
	}
	ast_variables_destroy(var);
	return user;
}

/*! \brief Locate user by name 
 * Locates user by name (From: sip uri user name part) first
 * from in-memory list (static configuration) then from 
 * realtime storage (defined in extconfig.conf) */
static struct sip_user *find_user(const char *name, int realtime)
{
	struct sip_user *u = ASTOBJ_CONTAINER_FIND(&userl, name);
	if (!u && realtime)
		u = realtime_user(name);
	return u;
}

/*! \brief Set nat mode on the various data sockets */
static void do_setnat(struct sip_pvt *p, int natflags)
{
	const char *mode = natflags ? "On" : "Off";

	if (p->rtp) {
		ast_debug(1, "Setting NAT on RTP to %s\n", mode);
		ast_rtp_setnat(p->rtp, natflags);
	}
	if (p->vrtp) {
		ast_debug(1, "Setting NAT on VRTP to %s\n", mode);
		ast_rtp_setnat(p->vrtp, natflags);
	}
	if (p->udptl) {
		ast_debug(1, "Setting NAT on UDPTL to %s\n", mode);
		ast_udptl_setnat(p->udptl, natflags);
	}
	if (p->trtp) {
		ast_debug(1, "Setting NAT on TRTP to %s\n", mode);
		ast_rtp_setnat(p->trtp, natflags);
	}
}

/*! \brief Set the global T38 capabilities on a SIP dialog structure */
static void set_t38_capabilities(struct sip_pvt *p)
{
	p->t38.capability = global_t38_capability;
	if (p->udptl) {
		if (ast_udptl_get_error_correction_scheme(p->udptl) == UDPTL_ERROR_CORRECTION_FEC )
			p->t38.capability |= T38FAX_UDP_EC_FEC;
		else if (ast_udptl_get_error_correction_scheme(p->udptl) == UDPTL_ERROR_CORRECTION_REDUNDANCY )
			p->t38.capability |= T38FAX_UDP_EC_REDUNDANCY;
		else if (ast_udptl_get_error_correction_scheme(p->udptl) == UDPTL_ERROR_CORRECTION_NONE )
			p->t38.capability |= T38FAX_UDP_EC_NONE;
		p->t38.capability |= T38FAX_RATE_MANAGEMENT_TRANSFERED_TCF;
	}
}

/*! \brief Create address structure from peer reference.
 *	This function copies data from peer to the dialog, so we don't have to look up the peer
 *	again from memory or database during the life time of the dialog.
 *
 * \return -1 on error, 0 on success.
 */
static int create_addr_from_peer(struct sip_pvt *dialog, struct sip_peer *peer)
{
	dialog->socket = peer->socket;

	if ((peer->addr.sin_addr.s_addr || peer->defaddr.sin_addr.s_addr) &&
	    (!peer->maxms || ((peer->lastms >= 0)  && (peer->lastms <= peer->maxms)))) {
		dialog->sa = (peer->addr.sin_addr.s_addr) ? peer->addr : peer->defaddr;
		dialog->recv = dialog->sa;
	} else 
		return -1;

	ast_copy_flags(&dialog->flags[0], &peer->flags[0], SIP_FLAGS_TO_COPY);
	ast_copy_flags(&dialog->flags[1], &peer->flags[1], SIP_PAGE2_FLAGS_TO_COPY);
	dialog->capability = peer->capability;
	if ((!ast_test_flag(&dialog->flags[1], SIP_PAGE2_VIDEOSUPPORT) || !(dialog->capability & AST_FORMAT_VIDEO_MASK)) && dialog->vrtp) {
		ast_rtp_destroy(dialog->vrtp);
		dialog->vrtp = NULL;
	}
	if (!ast_test_flag(&dialog->flags[1], SIP_PAGE2_TEXTSUPPORT) && dialog->trtp) {
		ast_rtp_destroy(dialog->trtp);
		dialog->trtp = NULL;
	}
	dialog->prefs = peer->prefs;
	if (ast_test_flag(&dialog->flags[1], SIP_PAGE2_T38SUPPORT)) {
		ast_copy_flags(&dialog->t38.t38support, &peer->flags[1], SIP_PAGE2_T38SUPPORT);
		set_t38_capabilities(dialog);
		dialog->t38.jointcapability = dialog->t38.capability;
	} else if (dialog->udptl) {
		ast_udptl_destroy(dialog->udptl);
		dialog->udptl = NULL;
	}
	do_setnat(dialog, ast_test_flag(&dialog->flags[0], SIP_NAT) & SIP_NAT_ROUTE);

	if (dialog->rtp) { /* Audio */
		ast_rtp_setdtmf(dialog->rtp, ast_test_flag(&dialog->flags[0], SIP_DTMF) == SIP_DTMF_RFC2833);
		ast_rtp_setdtmfcompensate(dialog->rtp, ast_test_flag(&dialog->flags[1], SIP_PAGE2_RFC2833_COMPENSATE));
		ast_rtp_set_rtptimeout(dialog->rtp, peer->rtptimeout);
		ast_rtp_set_rtpholdtimeout(dialog->rtp, peer->rtpholdtimeout);
		ast_rtp_set_rtpkeepalive(dialog->rtp, peer->rtpkeepalive);
		/* Set Frame packetization */
		ast_rtp_codec_setpref(dialog->rtp, &dialog->prefs);
		dialog->autoframing = peer->autoframing;
	}
	if (dialog->vrtp) { /* Video */
		ast_rtp_setdtmf(dialog->vrtp, 0);
		ast_rtp_setdtmfcompensate(dialog->vrtp, 0);
		ast_rtp_set_rtptimeout(dialog->vrtp, peer->rtptimeout);
		ast_rtp_set_rtpholdtimeout(dialog->vrtp, peer->rtpholdtimeout);
		ast_rtp_set_rtpkeepalive(dialog->vrtp, peer->rtpkeepalive);
	}
	if (dialog->trtp) { /* Realtime text */
		ast_rtp_setdtmf(dialog->trtp, 0);
		ast_rtp_setdtmfcompensate(dialog->trtp, 0);
		ast_rtp_set_rtptimeout(dialog->trtp, peer->rtptimeout);
		ast_rtp_set_rtpholdtimeout(dialog->trtp, peer->rtpholdtimeout);
		ast_rtp_set_rtpkeepalive(dialog->trtp, peer->rtpkeepalive);
	}

	ast_string_field_set(dialog, peername, peer->name);
	ast_string_field_set(dialog, authname, peer->username);
	ast_string_field_set(dialog, username, peer->username);
	ast_string_field_set(dialog, peersecret, peer->secret);
	ast_string_field_set(dialog, peermd5secret, peer->md5secret);
	ast_string_field_set(dialog, mohsuggest, peer->mohsuggest);
	ast_string_field_set(dialog, mohinterpret, peer->mohinterpret);
	ast_string_field_set(dialog, tohost, peer->tohost);
	ast_string_field_set(dialog, fullcontact, peer->fullcontact);
	ast_string_field_set(dialog, context, peer->context);
	dialog->outboundproxy = obproxy_get(dialog, peer);
	dialog->callgroup = peer->callgroup;
	dialog->pickupgroup = peer->pickupgroup;
	dialog->allowtransfer = peer->allowtransfer;
	dialog->jointnoncodeccapability = dialog->noncodeccapability;
	dialog->rtptimeout = peer->rtptimeout;
	dialog->maxcallbitrate = peer->maxcallbitrate;
	if (ast_strlen_zero(dialog->tohost))
		ast_string_field_set(dialog, tohost, ast_inet_ntoa(dialog->sa.sin_addr));
	if (!ast_strlen_zero(peer->fromdomain)) {
		ast_string_field_set(dialog, fromdomain, peer->fromdomain);
		if (!dialog->initreq.headers) {
			char *c;
			char *tmpcall = ast_strdupa(dialog->callid);

			c = strchr(tmpcall, '@');
			if (c) {
				*c = '\0';
				ast_string_field_build(dialog, callid, "%s@%s", tmpcall, peer->fromdomain);
			}
		}
	}
	if (!ast_strlen_zero(peer->fromuser)) 
		ast_string_field_set(dialog, fromuser, peer->fromuser);
	if (!ast_strlen_zero(peer->language))
		ast_string_field_set(dialog, language, peer->language);

	/* Set timer T1 to RTT for this peer (if known by qualify=) */
	/* Minimum is settable or default to 100 ms */
	/* If there is a maxms and lastms from a qualify use that over a manual T1
	   value. Otherwise, use the peer's T1 value. */
	if (peer->maxms && peer->lastms)
		dialog->timer_t1 = peer->lastms < global_t1min ? global_t1min : peer->lastms;
	else
		dialog->timer_t1 = peer->timer_t1;

	/* Set timer B to control transaction timeouts, the peer setting is the default and overrides
	   the known timer */
	if (peer->timer_b)
		dialog->timer_b = peer->timer_b;
	else
		dialog->timer_b = 64 * dialog->timer_t1;

	if ((ast_test_flag(&dialog->flags[0], SIP_DTMF) == SIP_DTMF_RFC2833) ||
	    (ast_test_flag(&dialog->flags[0], SIP_DTMF) == SIP_DTMF_AUTO))
		dialog->noncodeccapability |= AST_RTP_DTMF;
	else
		dialog->noncodeccapability &= ~AST_RTP_DTMF;
	if (peer->call_limit)
		ast_set_flag(&dialog->flags[0], SIP_CALL_LIMIT);
	
	return 0;
}

/*! \brief create address structure from peer name
 *      Or, if peer not found, find it in the global DNS 
 *      returns TRUE (-1) on failure, FALSE on success */
static int create_addr(struct sip_pvt *dialog, const char *opeer)
{
	struct hostent *hp;
	struct ast_hostent ahp;
	struct sip_peer *peer;
	char *port;
	int portno;
	char host[MAXHOSTNAMELEN], *hostn;
	char peername[256];

	ast_copy_string(peername, opeer, sizeof(peername));
	port = strchr(peername, ':');
	if (port)
		*port++ = '\0';
	dialog->sa.sin_family = AF_INET;
	dialog->timer_t1 = global_t1; /* Default SIP retransmission timer T1 (RFC 3261) */
	dialog->timer_b = global_timer_b; /* Default SIP transaction timer B (RFC 3261) */
	peer = find_peer(peername, NULL, 1);

	if (peer) {
		int res = create_addr_from_peer(dialog, peer);
		unref_peer(peer);
		return res;
	}

	ast_string_field_set(dialog, tohost, peername);

	/* Get the outbound proxy information */
	dialog->outboundproxy = obproxy_get(dialog, NULL);

	/* If we have an outbound proxy, don't bother with DNS resolution at all */
	if (dialog->outboundproxy)
		return 0;

	/* Let's see if we can find the host in DNS. First try DNS SRV records,
   	   then hostname lookup */

	hostn = peername;
	portno = port ? atoi(port) : (dialog->socket.type & SIP_TRANSPORT_TLS) ? STANDARD_TLS_PORT : STANDARD_SIP_PORT;
	if (global_srvlookup) {
		char service[MAXHOSTNAMELEN];
		int tportno;
		int ret;

		snprintf(service, sizeof(service), "_sip._%s.%s", get_transport(dialog->socket.type), peername);
		ret = ast_get_srv(NULL, host, sizeof(host), &tportno, service);
		if (ret > 0) {
			hostn = host;
			portno = tportno;
		}
	}
	hp = ast_gethostbyname(hostn, &ahp);
	if (!hp) {
		ast_log(LOG_WARNING, "No such host: %s\n", peername);
		return -1;
	}
	memcpy(&dialog->sa.sin_addr, hp->h_addr, sizeof(dialog->sa.sin_addr));
	dialog->sa.sin_port = htons(portno);
	dialog->recv = dialog->sa;
	return 0;
}

/*! \brief Scheduled congestion on a call.
 * Only called by the scheduler, must return the reference when done.
 */
static int auto_congest(const void *arg)
{
	struct sip_pvt *p = (struct sip_pvt *)arg;

	sip_pvt_lock(p);
	p->initid = -1;	/* event gone, will not be rescheduled */
	if (p->owner) {
		/* XXX fails on possible deadlock */
		if (!ast_channel_trylock(p->owner)) {
			ast_log(LOG_NOTICE, "Auto-congesting %s\n", p->owner->name);
			append_history(p, "Cong", "Auto-congesting (timer)");
			ast_queue_control(p->owner, AST_CONTROL_CONGESTION);
			ast_channel_unlock(p->owner);
		}
	}
	sip_pvt_unlock(p);
	dialog_unref(p);
	return 0;