chan_sip.c

	ASTOBJ_CONTAINER_COMPONENTS(struct sip_peer);
} peerl;

/*! \brief  The register list: Other SIP proxys we register with and place calls to */
static struct ast_register_list {
	ASTOBJ_CONTAINER_COMPONENTS(struct sip_registry);
	int recheck;
} regl;

/*! \todo Move the sip_auth list to AST_LIST */
static struct sip_auth *authl = NULL;		/*!< Authentication list for realm authentication */


/* --- Sockets and networking --------------*/
static int sipsock  = -1;			/*!< Main socket for SIP network communication */
static struct sockaddr_in bindaddr = { 0, };	/*!< The address we bind to */
static struct sockaddr_in externip;		/*!< External IP address if we are behind NAT */
static char externhost[MAXHOSTNAMELEN];		/*!< External host name (possibly with dynamic DNS and DHCP */
static time_t externexpire = 0;			/*!< Expiration counter for re-resolving external host name in dynamic DNS */
static int externrefresh = 10;
static struct ast_ha *localaddr;		/*!< List of local networks, on the same side of NAT as this Asterisk */
static struct in_addr __ourip;
static struct sockaddr_in outboundproxyip;
static int ourport;
static struct sockaddr_in debugaddr;

static struct ast_config *notify_types;		/*!< The list of manual NOTIFY types we know how to send */

/*---------------------------- Forward declarations of functions in chan_sip.c */
/*! \note Sorted up from start to build_rpid.... Will continue categorization in order to
	split up chan_sip.c into several files  */

/*--- PBX interface functions */
static struct ast_channel *sip_request_call(const char *type, int format, void *data, int *cause);
static int sip_devicestate(void *data);
static int sip_sendtext(struct ast_channel *ast, const char *text);
static int sip_call(struct ast_channel *ast, char *dest, int timeout);
static int sip_hangup(struct ast_channel *ast);
static int sip_answer(struct ast_channel *ast);
static struct ast_frame *sip_read(struct ast_channel *ast);
static int sip_write(struct ast_channel *ast, struct ast_frame *frame);
static int sip_indicate(struct ast_channel *ast, int condition, const void *data, size_t datalen);
static int sip_transfer(struct ast_channel *ast, const char *dest);
static int sip_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);
static int sip_senddigit(struct ast_channel *ast, char digit);

/*--- Transmitting responses and requests */
static int __sip_xmit(struct sip_pvt *p, char *data, int len);
static int __sip_reliable_xmit(struct sip_pvt *p, int seqno, int resp, char *data, int len, int fatal, int sipmethod);
static int __transmit_response(struct sip_pvt *p, const char *msg, struct sip_request *req, enum xmittype reliable);
static int transmit_response(struct sip_pvt *p, char *msg, struct sip_request *req);
static int transmit_response_reliable(struct sip_pvt *p, const char *msg, struct sip_request *req);
static int transmit_response_with_date(struct sip_pvt *p, char *msg, struct sip_request *req);
static int transmit_response_with_sdp(struct sip_pvt *p, char *msg, struct sip_request *req, enum xmittype reliable);
static int transmit_response_with_unsupported(struct sip_pvt *p, const char *msg, struct sip_request *req, const char *unsupported);
static int transmit_response_with_auth(struct sip_pvt *p, const char *msg, struct sip_request *req, const char *rand, enum xmittype reliable, const char *header, int stale);
static int transmit_response_with_allow(struct sip_pvt *p, char *msg, struct sip_request *req, enum xmittype reliable);
static int transmit_request(struct sip_pvt *p, int sipmethod, int inc, enum xmittype reliable, int newbranch);
static int transmit_request_with_auth(struct sip_pvt *p, int sipmethod, int inc, enum xmittype reliable, int newbranch);
static int transmit_invite(struct sip_pvt *p, int sipmethod, int sendsdp, int init);
static int transmit_reinvite_with_sdp(struct sip_pvt *p);
static int transmit_info_with_digit(struct sip_pvt *p, char digit);
static int transmit_info_with_vidupdate(struct sip_pvt *p);
static int transmit_message_with_text(struct sip_pvt *p, const char *text);
static int transmit_refer(struct sip_pvt *p, const char *dest);
static int transmit_state_notify(struct sip_pvt *p, int state, int full);
static int transmit_register(struct sip_registry *r, int sipmethod, char *auth, char *authheader);
static int retrans_pkt(void *data);
static int send_response(struct sip_pvt *p, struct sip_request *req, enum xmittype reliable, int seqno);
static int send_request(struct sip_pvt *p, struct sip_request *req, enum xmittype reliable, int seqno);
static void copy_request(struct sip_request *dst, struct sip_request *src);

/*--- Dialog management */
static struct sip_pvt *sip_alloc(ast_string_field callid, struct sockaddr_in *sin,
				 int useglobal_nat, const int intended_method);
static int __sip_autodestruct(void *data);
static int sip_scheddestroy(struct sip_pvt *p, int ms);
static int sip_cancel_destroy(struct sip_pvt *p);
static void sip_destroy(struct sip_pvt *p);
static void __sip_destroy(struct sip_pvt *p, int lockowner);
static int __sip_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod, int reset);
static int __sip_pretend_ack(struct sip_pvt *p);
static int __sip_semi_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod);
static int auto_congest(void *nothing);
static int update_call_counter(struct sip_pvt *fup, int event);
static int hangup_sip2cause(int cause);
static const char *hangup_cause2sip(int cause);
static int sip_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);
static struct sip_pvt *find_call(struct sip_request *req, struct sockaddr_in *sin, const int intended_method);

/*--- Codec handling / SDP */
static void try_suggested_sip_codec(struct sip_pvt *p);
static const char *get_sdp_by_line(const char* line, const char *name, int nameLen);
static const char* get_sdp_iterate(int* start, struct sip_request *req, const char *name);
static const char *get_sdp(struct sip_request *req, const char *name);
static int process_sdp(struct sip_pvt *p, struct sip_request *req);
static void add_codec_to_sdp(const struct sip_pvt *p, int codec, int sample_rate,
			     char **m_buf, size_t *m_size, char **a_buf, size_t *a_size,
			     int debug);
static void add_noncodec_to_sdp(const struct sip_pvt *p, int format, int sample_rate,
				char **m_buf, size_t *m_size, char **a_buf, size_t *a_size,
				int debug);
static int add_sdp(struct sip_request *resp, struct sip_pvt *p);

/*--- Authentication stuff */
static int do_proxy_auth(struct sip_pvt *p, struct sip_request *req, char *header, char *respheader, int sipmethod, int init);
static int reply_digest(struct sip_pvt *p, struct sip_request *req, char *header, int sipmethod, char *digest, int digest_len);
static int build_reply_digest(struct sip_pvt *p, int method, char *digest, int digest_len);
static int clear_realm_authentication(struct sip_auth *authlist);	/* Clear realm authentication list (at reload) */
static struct sip_auth *add_realm_authentication(struct sip_auth *authlist, char *configuration, int lineno);	/* Add realm authentication in list */
static struct sip_auth *find_realm_authentication(struct sip_auth *authlist, const char *realm);	/* Find authentication for a specific realm */
static int check_auth(struct sip_pvt *p, struct sip_request *req, const char *username,
		const char *secret, const char *md5secret, int sipmethod,
		char *uri, enum xmittype reliable, int ignore);

/*--- Domain handling */
static int check_sip_domain(const char *domain, char *context, size_t len); /* Check if domain is one of our local domains */

static void free_old_route(struct sip_route *route);

/*--- Misc functions */
static int sip_do_reload(enum channelreloadreason reason);
static int expire_register(void *data);
static int sip_sipredirect(struct sip_pvt *p, const char *dest);
static int restart_monitor(void);
static int sip_send_mwi_to_peer(struct sip_peer *peer);
static void sip_destroy(struct sip_pvt *p);
static int sip_scheddestroy(struct sip_pvt *p, int ms);
static int sip_addrcmp(char *name, struct sockaddr_in *sin);	/* Support for peer matching */

/*--- CLI and manager command helpers */
static const char *sip_nat_mode(const struct sip_pvt *p);

/*--- Debugging */
static void sip_dump_history(struct sip_pvt *dialog);	/* Dump history to LOG_DEBUG at end of dialog, before destroying data */
static inline int sip_debug_test_addr(const struct sockaddr_in *addr);
static inline int sip_debug_test_pvt(struct sip_pvt *p);
static int append_history_full(struct sip_pvt *p, const char *fmt, ...);

/*--- Device object handling */
static struct sip_peer *temp_peer(const char *name);
static struct sip_peer *build_peer(const char *name, struct ast_variable *v, int realtime);
static struct sip_user *build_user(const char *name, struct ast_variable *v, int realtime);
static int update_call_counter(struct sip_pvt *fup, int event);
static void sip_destroy_peer(struct sip_peer *peer);
static void sip_destroy_user(struct sip_user *user);
static int sip_poke_peer(struct sip_peer *peer);
static void set_peer_defaults(struct sip_peer *peer);
static struct sip_peer *temp_peer(const char *name);
static void register_peer_exten(struct sip_peer *peer, int onoff);
static void sip_destroy_peer(struct sip_peer *peer);
static void sip_destroy_user(struct sip_user *user);
static struct sip_peer *find_peer(const char *peer, struct sockaddr_in *sin, int realtime);
static struct sip_user *find_user(const char *name, int realtime);
/* Realtime device support */
static void realtime_update_peer(const char *peername, struct sockaddr_in *sin, const char *username, const char *fullcontact, int expirey);
static struct sip_user *realtime_user(const char *username);
static void update_peer(struct sip_peer *p, int expiry);
static struct sip_peer *realtime_peer(const char *peername, struct sockaddr_in *sin);

/*--- Internal UA client handling (outbound registrations) */
static int __sip_do_register(struct sip_registry *r);
static int ast_sip_ouraddrfor(struct in_addr *them, struct in_addr *us);
static void sip_registry_destroy(struct sip_registry *reg);
static int sip_register(char *value, int lineno);

/*--- Parsing SIP requests and responses */
static void append_date(struct sip_request *req);	/* Append date to SIP packet */
static int determine_firstline_parts(struct sip_request *req);
static const struct cfsubscription_types *find_subscription_type(enum subscriptiontype subtype);
static const char *gettag(const struct sip_request *req, char *header, char *tagbuf, int tagbufsize);
static int find_sip_method(const char *msg);
static unsigned int parse_sip_options(struct sip_pvt *pvt, const char *supported);
static void parse_request(struct sip_request *req);
static const char *get_header(const struct sip_request *req, const char *name);
static char *referstatus2str(enum referstatus rstatus);
static int method_match(enum sipmethod id, const char *name);
static void parse_copy(struct sip_request *dst, struct sip_request *src);
static char *get_in_brackets(char *tmp);
static const char *find_alias(const char *name, const char *_default);
static const char *__get_header(const struct sip_request *req, const char *name, int *start);
static const char *get_header(const struct sip_request *req, const char *name);
static int lws2sws(char *msgbuf, int len);
static void extract_uri(struct sip_pvt *p, struct sip_request *req);

/*--- Constructing requests and responses */
static void initialize_initreq(struct sip_pvt *p, struct sip_request *req);
static int init_req(struct sip_request *req, int sipmethod, const char *recip);
static int reqprep(struct sip_request *req, struct sip_pvt *p, int sipmethod, int seqno, int newbranch);
static int init_resp(struct sip_request *resp, const char *msg);
static int respprep(struct sip_request *resp, struct sip_pvt *p, const char *msg, struct sip_request *req);
static const struct sockaddr_in *sip_real_dst(const struct sip_pvt *p);
static void build_via(struct sip_pvt *p);
static int create_addr_from_peer(struct sip_pvt *r, struct sip_peer *peer);
static int create_addr(struct sip_pvt *dialog, const char *opeer);
static char *generate_random_string(char *buf, size_t size);
static void build_callid_pvt(struct sip_pvt *pvt);
static void build_callid_registry(struct sip_registry *reg, struct in_addr ourip, const char *fromdomain);
static void make_our_tag(char *tagbuf, size_t len);
static int add_header(struct sip_request *req, const char *var, const char *value);
static int add_header_contentLength(struct sip_request *req, int len);
static int add_line(struct sip_request *req, const char *line);
static int add_text(struct sip_request *req, const char *text);
static int add_digit(struct sip_request *req, char digit);
static int add_vidupdate(struct sip_request *req);
static void add_route(struct sip_request *req, struct sip_route *route);
static int copy_header(struct sip_request *req, struct sip_request *orig, char *field);
static int copy_all_header(struct sip_request *req, struct sip_request *orig, char *field);
static int copy_via_headers(struct sip_pvt *p, struct sip_request *req, struct sip_request *orig, char *field);
static void set_destination(struct sip_pvt *p, char *uri);
static void append_date(struct sip_request *req);
static void build_contact(struct sip_pvt *p);
static void build_rpid(struct sip_pvt *p);

/*------Request handling functions */
static int handle_request_invite(struct sip_pvt *p, struct sip_request *req, int debug, int seqno, struct sockaddr_in *sin, int *recount, char *e);
static int handle_request_refer(struct sip_pvt *p, struct sip_request *req, int debug, int ignore, int seqno, int *nounlock);
static int handle_request_bye(struct sip_pvt *p, struct sip_request *req);
static int handle_request_register(struct sip_pvt *p, struct sip_request *req, struct sockaddr_in *sin, char *e);
static int handle_request_cancel(struct sip_pvt *p, struct sip_request *req);
static int handle_request_message(struct sip_pvt *p, struct sip_request *req);
static int handle_request_subscribe(struct sip_pvt *p, struct sip_request *req, struct sockaddr_in *sin, int seqno, char *e);
static void handle_request_info(struct sip_pvt *p, struct sip_request *req);
static int handle_request_options(struct sip_pvt *p, struct sip_request *req);

/*------Response handling functions */
static void handle_response_invite(struct sip_pvt *p, int resp, char *rest, struct sip_request *req, int seqno);
static void handle_response_refer(struct sip_pvt *p, int resp, char *rest, struct sip_request *req, int seqno);
static int handle_response_peerpoke(struct sip_pvt *p, int resp, struct sip_request *req);

/*----- RTP interface functions */
static int sip_set_rtp_peer(struct ast_channel *chan, struct ast_rtp *rtp, struct ast_rtp *vrtp, int codecs, int nat_active);
static struct ast_rtp *sip_get_rtp_peer(struct ast_channel *chan);
static struct ast_rtp *sip_get_vrtp_peer(struct ast_channel *chan);
static int sip_get_codec(struct ast_channel *chan);
static struct ast_frame *sip_rtp_read(struct ast_channel *ast, struct sip_pvt *p);

/*! \brief Definition of this channel for PBX channel registration */
static const struct ast_channel_tech sip_tech = {
	.type = "SIP",
	.description = "Session Initiation Protocol (SIP)",
	.capabilities = ((AST_FORMAT_MAX_AUDIO << 1) - 1),
	.properties = AST_CHAN_TP_WANTSJITTER,
	.requester = sip_request_call,
	.devicestate = sip_devicestate,
	.call = sip_call,
	.hangup = sip_hangup,
	.answer = sip_answer,
	.read = sip_read,
	.write = sip_write,
	.write_video = sip_write,
	.indicate = sip_indicate,
	.transfer = sip_transfer,
	.fixup = sip_fixup,
	.send_digit = sip_senddigit,
	.bridge = ast_rtp_bridge,
	.send_text = sip_sendtext,
};

/**--- some list management macros. **/
 
#define UNLINK(element, head, prev) do {	\
	if (prev)				\
		(prev)->next = (element)->next;	\
	else					\
		(head) = (element)->next;	\
	} while (0)

/*! \brief Interface structure with callbacks used to connect to RTP module */
static struct ast_rtp_protocol sip_rtp = {
	type: "SIP",
	get_rtp_info: sip_get_rtp_peer,
	get_vrtp_info: sip_get_vrtp_peer,
	set_rtp_peer: sip_set_rtp_peer,
	get_codec: sip_get_codec,
};

/*! \brief Convert transfer status to string */
static char *referstatus2str(enum referstatus rstatus)
{
	int i = (sizeof(referstatusstrings) / sizeof(referstatusstrings[0]));
	int x;

	for (x = 0; x < i; x++) {
		if (referstatusstrings[x].status ==  rstatus)
			return (char *) referstatusstrings[x].text;
	}
	return "";
}

/*! \brief Initialize the initital request packet in the pvt structure.
 	This packet is used for creating replies and future requests in
	a dialog */
static void initialize_initreq(struct sip_pvt *p, struct sip_request *req)
{
	if (p->initreq.headers) {
		ast_log(LOG_DEBUG, "Initializing already initialized SIP dialog %s (presumably reinvite)\n", p->callid);
	}
	/* Use this as the basis */
	copy_request(&p->initreq, req);
	parse_request(&p->initreq);
	if (ast_test_flag(req, SIP_PKT_DEBUG))
		ast_verbose("%d headers, %d lines\n", p->initreq.headers, p->initreq.lines);
}


/*! \brief returns true if 'name' (with optional trailing whitespace)
 * matches the sip method 'id'.
 * Strictly speaking, SIP methods are case SENSITIVE, but we do
 * a case-insensitive comparison to be more tolerant.
 * following Jon Postel's rule: Be gentle in what you accept, strict with what you send
 */
static int method_match(enum sipmethod id, const char *name)
{
	int len = strlen(sip_methods[id].text);
	int l_name = name ? strlen(name) : 0;
	/* true if the string is long enough, and ends with whitespace, and matches */
	return (l_name >= len && name[len] < 33 &&
		!strncasecmp(sip_methods[id].text, name, len));
}

/*! \brief  find_sip_method: Find SIP method from header */
static int find_sip_method(const char *msg)
{
	int i, res = 0;
	
	if (ast_strlen_zero(msg))
		return 0;
	for (i = 1; i < (sizeof(sip_methods) / sizeof(sip_methods[0])) && !res; i++) {
		if (method_match(i, msg))
			res = sip_methods[i].id;
	}
	return res;
}

/*! \brief Parse supported header in incoming packet */
static unsigned int parse_sip_options(struct sip_pvt *pvt, const char *supported)
{
	char *next, *sep;
	char *temp = ast_strdupa(supported);
	unsigned int profile = 0;
	int i, found;

	if (!pvt || ast_strlen_zero(supported) )
		return 0;

	if (option_debug > 2 && sipdebug)
		ast_log(LOG_DEBUG, "Begin: parsing SIP \"Supported: %s\"\n", supported);

	for (next = temp; next; next = sep) {
		found = FALSE;
		if ( (sep = strchr(next, ',')) != NULL)
			*sep++ = '\0';
		next = ast_skip_blanks(next);
		if (option_debug > 2 && sipdebug)
			ast_log(LOG_DEBUG, "Found SIP option: -%s-\n", next);
		for (i=0; i < (sizeof(sip_options) / sizeof(sip_options[0])); i++) {
			if (!strcasecmp(next, sip_options[i].text)) {
				profile |= sip_options[i].id;
				found = TRUE;
				if (option_debug > 2 && sipdebug)
					ast_log(LOG_DEBUG, "Matched SIP option: %s\n", next);
				break;
			}
		}
		if (!found && option_debug > 2 && sipdebug)
			ast_log(LOG_DEBUG, "Found no match for SIP option: %s (Please file bug report!)\n", next);
	}

	pvt->sipoptions = profile;
	return profile;
}

/*! \brief See if we pass debug IP filter */
static inline int sip_debug_test_addr(const struct sockaddr_in *addr) 
{
	if (!sipdebug)
		return 0;
	if (debugaddr.sin_addr.s_addr) {
		if (((ntohs(debugaddr.sin_port) != 0)
			&& (debugaddr.sin_port != addr->sin_port))
			|| (debugaddr.sin_addr.s_addr != addr->sin_addr.s_addr))
			return 0;
	}
	return 1;
}

/*! \brief The real destination address for a write */
static const struct sockaddr_in *sip_real_dst(const struct sip_pvt *p)
{
	return ast_test_flag(&p->flags[0], SIP_NAT) & SIP_NAT_ROUTE ? &p->recv : &p->sa;
}

/*! \brief Display SIP nat mode */
static const char *sip_nat_mode(const struct sip_pvt *p)
{
	return ast_test_flag(&p->flags[0], SIP_NAT) & SIP_NAT_ROUTE ? "NAT" : "no NAT";
}

/*! \brief Test PVT for debugging output */
static inline int sip_debug_test_pvt(struct sip_pvt *p) 
{
	if (!sipdebug)
		return 0;
	return sip_debug_test_addr(sip_real_dst(p));
}

/*! \brief Transmit SIP message */
static int __sip_xmit(struct sip_pvt *p, char *data, int len)
{
	int res;
	char iabuf[INET_ADDRSTRLEN];
	const struct sockaddr_in *dst = sip_real_dst(p);
	res=sendto(sipsock, data, len, 0, (const struct sockaddr *)dst, sizeof(struct sockaddr_in));

	if (res != len)
		ast_log(LOG_WARNING, "sip_xmit of %p (len %d) to %s:%d returned %d: %s\n", data, len, ast_inet_ntoa(iabuf, sizeof(iabuf), dst->sin_addr), ntohs(dst->sin_port), res, strerror(errno));
	return res;
}


/*! \brief Build a Via header for a request */
static void build_via(struct sip_pvt *p)
{
	char iabuf[INET_ADDRSTRLEN];
	/* Work around buggy UNIDEN UIP200 firmware */
	const char *rport = ast_test_flag(&p->flags[0], SIP_NAT) & SIP_NAT_RFC3581 ? ";rport" : "";

	/* z9hG4bK is a magic cookie.  See RFC 3261 section 8.1.1.7 */
	ast_string_field_build(p, via, "SIP/2.0/UDP %s:%d;branch=z9hG4bK%08x%s",
			 ast_inet_ntoa(iabuf, sizeof(iabuf), p->ourip), ourport, p->branch, rport);
}

/*! \brief NAT fix - decide which IP address to use for ASterisk server?
 * Only used for outbound registrations */
static int ast_sip_ouraddrfor(struct in_addr *them, struct in_addr *us)
{
	/*
	 * Using the localaddr structure built up with localnet statements
	 * apply it to their address to see if we need to substitute our
	 * externip or can get away with our internal bindaddr
	 */
	struct sockaddr_in theirs;
	theirs.sin_addr = *them;

	if (localaddr && externip.sin_addr.s_addr &&
	   ast_apply_ha(localaddr, &theirs)) {
		if (externexpire && time(NULL) >= externexpire) {
			struct ast_hostent ahp;
			struct hostent *hp;

			time(&externexpire);
			externexpire += externrefresh;
			if ((hp = ast_gethostbyname(externhost, &ahp))) {
				memcpy(&externip.sin_addr, hp->h_addr, sizeof(externip.sin_addr));
			} else
				ast_log(LOG_NOTICE, "Warning: Re-lookup of '%s' failed!\n", externhost);
		}
		*us = externip.sin_addr;
		if (option_debug) {
			char iabuf[INET_ADDRSTRLEN];
			ast_inet_ntoa(iabuf, sizeof(iabuf), *(struct in_addr *)&them->s_addr);
		
			ast_log(LOG_DEBUG, "Target address %s is not local, substituting externip\n", iabuf);
		}
	} else if (bindaddr.sin_addr.s_addr)
		*us = bindaddr.sin_addr;
	else
		return ast_ouraddrfor(them, us);
	return 0;
}

/*! \brief Append to SIP dialog history 
	\return Always returns 0 */
#define append_history(p, event, fmt , args... )	append_history_full(p, "%-15s " fmt, event, ## args)

static int append_history_full(struct sip_pvt *p, const char *fmt, ...)
	__attribute__ ((format (printf, 2, 3)));

/*! \brief Append to SIP dialog history with arg list  */
static void append_history_va(struct sip_pvt *p, const char *fmt, va_list ap)
{
	char buf[80], *c = buf; /* max history length */
	struct sip_history *hist;
	int l;

	vsnprintf(buf, sizeof(buf), fmt, ap);
	strsep(&c, "\r\n"); /* Trim up everything after \r or \n */
	l = strlen(buf) + 1;
	if (!(hist = ast_calloc(1, sizeof(*hist) + l)))
		return;
	if (!p->history && !(p->history = ast_calloc(1, sizeof(*p->history)))) {
		free(hist);
		return;
	}
	memcpy(hist->event, buf, l);
	AST_LIST_INSERT_TAIL(p->history, hist, list);
}

/*! \brief Append to SIP dialog history with arg list  */
static int append_history_full(struct sip_pvt *p, const char *fmt, ...)
{
	va_list ap;

	if (!recordhistory || !p)
		return 0;
	va_start(ap, fmt);
	append_history_va(p, fmt, ap);
	va_end(ap);

	return 0;
}

/*! \brief Retransmit SIP message if no answer (Called from scheduler) */
static int retrans_pkt(void *data)
{
	struct sip_pkt *pkt = data, *prev, *cur = NULL;
	char iabuf[INET_ADDRSTRLEN];
	int reschedule = DEFAULT_RETRANS;

	/* Lock channel PVT */
	ast_mutex_lock(&pkt->owner->lock);

	if (pkt->retrans < MAX_RETRANS) {
		pkt->retrans++;
 		if (!pkt->timer_t1) {	/* Re-schedule using timer_a and timer_t1 */
			if (sipdebug && option_debug > 3)
 				ast_log(LOG_DEBUG, "SIP TIMER: Not rescheduling id #%d:%s (Method %d) (No timer T1)\n", pkt->retransid, sip_methods[pkt->method].text, pkt->method);
		} else {
 			int siptimer_a;

 			if (sipdebug && option_debug > 3)
 				ast_log(LOG_DEBUG, "SIP TIMER: Rescheduling retransmission #%d (%d) %s - %d\n", pkt->retransid, pkt->retrans, sip_methods[pkt->method].text, pkt->method);
 			if (!pkt->timer_a)
 				pkt->timer_a = 2 ;
 			else
 				pkt->timer_a = 2 * pkt->timer_a;
 
 			/* For non-invites, a maximum of 4 secs */
 			siptimer_a = pkt->timer_t1 * pkt->timer_a;	/* Double each time */
 			if (pkt->method != SIP_INVITE && siptimer_a > 4000)
 				siptimer_a = 4000;
 		
 			/* Reschedule re-transmit */
			reschedule = siptimer_a;
 			if (option_debug > 3)
 				ast_log(LOG_DEBUG, "** SIP timers: Rescheduling retransmission %d to %d ms (t1 %d ms (Retrans id #%d)) \n", pkt->retrans +1, siptimer_a, pkt->timer_t1, pkt->retransid);
 		} 

		if (pkt->owner && sip_debug_test_pvt(pkt->owner)) {
			if (ast_test_flag(&pkt->owner->flags[0], SIP_NAT_ROUTE))
				ast_verbose("Retransmitting #%d (NAT) to %s:%d:\n%s\n---\n", pkt->retrans, ast_inet_ntoa(iabuf, sizeof(iabuf), pkt->owner->recv.sin_addr), ntohs(pkt->owner->recv.sin_port), pkt->data);
			else
				ast_verbose("Retransmitting #%d (no NAT) to %s:%d:\n%s\n---\n", pkt->retrans, ast_inet_ntoa(iabuf, sizeof(iabuf), pkt->owner->sa.sin_addr), ntohs(pkt->owner->sa.sin_port), pkt->data);
		}

		append_history(pkt->owner, "ReTx", "%d %s", reschedule, pkt->data);
		__sip_xmit(pkt->owner, pkt->data, pkt->packetlen);
		ast_mutex_unlock(&pkt->owner->lock);
		return  reschedule;
	} 
	/* Too many retries */
	if (pkt->owner && pkt->method != SIP_OPTIONS) {
		if (ast_test_flag(pkt, FLAG_FATAL) || sipdebug)	/* Tell us if it's critical or if we're debugging */
			ast_log(LOG_WARNING, "Maximum retries exceeded on transmission %s for seqno %d (%s %s)\n", pkt->owner->callid, pkt->seqno, (ast_test_flag(pkt, FLAG_FATAL)) ? "Critical" : "Non-critical", (ast_test_flag(pkt, FLAG_RESPONSE)) ? "Response" : "Request");
	} else {
		if ((pkt->method == SIP_OPTIONS) && sipdebug)
			ast_log(LOG_WARNING, "Cancelling retransmit of OPTIONs (call id %s) \n", pkt->owner->callid);
	}
	append_history(pkt->owner, "MaxRetries", "%s", (ast_test_flag(pkt, FLAG_FATAL)) ? "(Critical)" : "(Non-critical)");
 		
	pkt->retransid = -1;

	if (ast_test_flag(pkt, FLAG_FATAL)) {
		while(pkt->owner->owner && ast_mutex_trylock(&pkt->owner->owner->lock)) {
			ast_mutex_unlock(&pkt->owner->lock);
			usleep(1);
			ast_mutex_lock(&pkt->owner->lock);
		}
		if (pkt->owner->owner) {
			ast_set_flag(&pkt->owner->flags[0], SIP_ALREADYGONE);
			ast_log(LOG_WARNING, "Hanging up call %s - no reply to our critical packet.\n", pkt->owner->callid);
			ast_queue_hangup(pkt->owner->owner);
			ast_channel_unlock(pkt->owner->owner);
		} else {
			/* If no channel owner, destroy now */
			ast_set_flag(&pkt->owner->flags[0], SIP_NEEDDESTROY);	
		}
	}
	/* In any case, go ahead and remove the packet */
	for (prev = NULL, cur = pkt->owner->packets; cur; prev = cur, cur = cur->next) {
		if (cur == pkt)
			break;
	}
	if (cur) {
		if (prev)
			prev->next = cur->next;
		else
			pkt->owner->packets = cur->next;
		ast_mutex_unlock(&pkt->owner->lock);
		free(cur);
		pkt = NULL;
	} else
		ast_log(LOG_WARNING, "Weird, couldn't find packet owner!\n");
	if (pkt)
		ast_mutex_unlock(&pkt->owner->lock);
	return 0;
}

/*! \brief Transmit packet with retransmits 
	\return 0 on success, -1 on failure to allocate packet 
*/
static int __sip_reliable_xmit(struct sip_pvt *p, int seqno, int resp, char *data, int len, int fatal, int sipmethod)
{
	struct sip_pkt *pkt;
	int siptimer_a = DEFAULT_RETRANS;

	if (!(pkt = ast_calloc(1, sizeof(*pkt) + len + 1)))
		return -1;
	memcpy(pkt->data, data, len);
	pkt->method = sipmethod;
	pkt->packetlen = len;
	pkt->next = p->packets;
	pkt->owner = p;
	pkt->seqno = seqno;
	pkt->flags = resp;
	pkt->data[len] = '\0';
	pkt->timer_t1 = p->timer_t1;	/* Set SIP timer T1 */
	if (fatal)
		ast_set_flag(pkt, FLAG_FATAL);
	if (pkt->timer_t1)
		siptimer_a = pkt->timer_t1 * 2;

	/* Schedule retransmission */
	pkt->retransid = ast_sched_add_variable(sched, siptimer_a, retrans_pkt, pkt, 1);
	if (option_debug > 3 && sipdebug)
		ast_log(LOG_DEBUG, "*** SIP TIMER: Initalizing retransmit timer on packet: Id  #%d\n", pkt->retransid);
	pkt->next = p->packets;
	p->packets = pkt;

	__sip_xmit(pkt->owner, pkt->data, pkt->packetlen);	/* Send packet */
	if (sipmethod == SIP_INVITE) {
		/* Note this is a pending invite */
		p->pendinginvite = seqno;
	}
	return 0;
}

/*! \brief Kill a SIP dialog (called by scheduler) */
static int __sip_autodestruct(void *data)
{
	struct sip_pvt *p = data;

	/* If this is a subscription, tell the phone that we got a timeout */
	if (p->subscribed) {
		p->subscribed = TIMEOUT;
		transmit_state_notify(p, AST_EXTENSION_DEACTIVATED, 1);	/* Send last notification */
		p->subscribed = NONE;
		append_history(p, "Subscribestatus", "timeout");
		if (option_debug > 2)
			ast_log(LOG_DEBUG, "Re-scheduled destruction of SIP subsription %s\n", p->callid ? p->callid : "<unknown>");
		return 10000;	/* Reschedule this destruction so that we know that it's gone */
	}

	/* Reset schedule ID */
	p->autokillid = -1;

	if (option_debug)
		ast_log(LOG_DEBUG, "Auto destroying call '%s'\n", p->callid);
	append_history(p, "AutoDestroy", "");
	if (p->owner) {
		ast_log(LOG_WARNING, "Autodestruct on dialog '%s' with owner in place (Method: %s)\n", p->callid, sip_methods[p->method].text);
		ast_queue_hangup(p->owner);
	} else {
		sip_destroy(p);
	}
	return 0;
}

/*! \brief Schedule destruction of SIP call */
static int sip_scheddestroy(struct sip_pvt *p, int ms)
{
	if (sip_debug_test_pvt(p))
		ast_verbose("Scheduling destruction of SIP dialog '%s' in %d ms (Method: %s)\n", p->callid, ms, sip_methods[p->method].text);
	if (recordhistory)
		append_history(p, "SchedDestroy", "%d ms", ms);

	if (p->autokillid > -1)
		ast_sched_del(sched, p->autokillid);
	p->autokillid = ast_sched_add(sched, ms, __sip_autodestruct, p);
	return 0;
}

/*! \brief Cancel destruction of SIP dialog */
static int sip_cancel_destroy(struct sip_pvt *p)
{
	if (p->autokillid > -1) {
		ast_sched_del(sched, p->autokillid);
		append_history(p, "CancelDestroy", "");
		p->autokillid = -1;
	}
	return 0;
}

/*! \brief Acknowledges receipt of a packet and stops retransmission */
static int __sip_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod, int reset)
{
	struct sip_pkt *cur, *prev = NULL;
	int res = -1;

	/* Just in case... */
	char *msg;

	msg = sip_methods[sipmethod].text;

	ast_mutex_lock(&p->lock);
	for (cur = p->packets; cur; prev = cur, cur = cur->next) {
		if ((cur->seqno == seqno) && ((ast_test_flag(cur, FLAG_RESPONSE)) == resp) &&
			((ast_test_flag(cur, FLAG_RESPONSE)) || 
			 (!strncasecmp(msg, cur->data, strlen(msg)) && (cur->data[strlen(msg)] < 33)))) {
			if (!resp && (seqno == p->pendinginvite)) {
				ast_log(LOG_DEBUG, "Acked pending invite %d\n", p->pendinginvite);
				p->pendinginvite = 0;
			}
			/* this is our baby */
			UNLINK(cur, p->packets, prev);
			if (cur->retransid > -1) {
				if (sipdebug && option_debug > 3)
					ast_log(LOG_DEBUG, "** SIP TIMER: Cancelling retransmit of packet (reply received) Retransid #%d\n", cur->retransid);
				ast_sched_del(sched, cur->retransid);
			}
			if (!reset)
				free(cur);
			res = 0;
			break;
		}
	}
	ast_mutex_unlock(&p->lock);
	if (option_debug)
		ast_log(LOG_DEBUG, "Stopping retransmission on '%s' of %s %d: Match %s\n", p->callid, resp ? "Response" : "Request", seqno, res ? "Not Found" : "Found");
	return res;
}

/*! \brief Pretend to ack all packets */
/* maybe the lock on p is not strictly necessary but there might be a race */
static int __sip_pretend_ack(struct sip_pvt *p)
{
	struct sip_pkt *cur = NULL;

	while (p->packets) {
		int method;
		if (cur == p->packets) {
			ast_log(LOG_WARNING, "Have a packet that doesn't want to give up! %s\n", sip_methods[cur->method].text);
			return -1;
		}
		cur = p->packets;
		method = (cur->method) ? cur->method : find_sip_method(cur->data);
		__sip_ack(p, cur->seqno, ast_test_flag(cur, FLAG_RESPONSE), method, FALSE);
	}
	return 0;
}

/*! \brief Acks receipt of packet, keep it around (used for provisional responses) */
static int __sip_semi_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod)
{
	struct sip_pkt *cur;
	int res = -1;

	for (cur = p->packets; cur; cur = cur->next) {
		if (cur->seqno == seqno && ast_test_flag(cur, FLAG_RESPONSE) == resp &&
			(ast_test_flag(cur, FLAG_RESPONSE) || method_match(sipmethod, cur->data))) {
			/* this is our baby */
			if (cur->retransid > -1) {
				if (option_debug > 3 && sipdebug)
					ast_log(LOG_DEBUG, "*** SIP TIMER: Cancelling retransmission #%d - %s (got response)\n", cur->retransid, sip_methods[sipmethod].text);
				ast_sched_del(sched, cur->retransid);
			}
			cur->retransid = -1;
			res = 0;
			break;
		}
	}
	if (option_debug)
		ast_log(LOG_DEBUG, "(Provisional) Stopping retransmission (but retaining packet) on '%s' %s %d: %s\n", p->callid, resp ? "Response" : "Request", seqno, res ? "Not Found" : "Found");
	return res;
}


/*! \brief Copy SIP request, parse it */
static void parse_copy(struct sip_request *dst, struct sip_request *src)
{
	memset(dst, 0, sizeof(*dst));
	memcpy(dst->data, src->data, sizeof(dst->data));
	dst->len = src->len;
	parse_request(dst);
}

/* 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 */
		snprintf(req->data + req->len, sizeof(req->data) - req->len, "\r\n");
		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)) {
		char iabuf[INET_ADDRSTRLEN];
		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(iabuf, sizeof(iabuf), 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(iabuf, sizeof(iabuf), p->sa.sin_addr), ntohs(p->sa.sin_port), req->data);
	}
	if (recordhistory) {
		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.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;

	add_blank(req);
	if (sip_debug_test_pvt(p)) {
		char iabuf[INET_ADDRSTRLEN];
		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(iabuf, sizeof(iabuf), 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(iabuf, sizeof(iabuf), p->sa.sin_addr), ntohs(p->sa.sin_port), req->data);
	}
	if (recordhistory) {
		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 > 1), req->method) :
		__sip_xmit(p, req->data, req->len);
	return res;
}

/*! \brief Pick out text in brackets from character string
	\return pointer to terminated stripped string
	\param tmp input string that will be modified */
static char *get_in_brackets(char *tmp)
{
	char *parse;
	char *first_quote;
	char *first_bracket;
	char *second_bracket;
	char last_char;

	parse = tmp;
	for (;;) {
		first_quote = strchr(parse, '"');
		first_bracket = strchr(parse, '<');
		if (first_quote && first_bracket && (first_quote < first_bracket)) {
			last_char = '\0';
			for (parse = first_quote + 1; *parse; parse++) {
				if ((*parse == '"') && (last_char != '\\'))
					break;
				last_char = *parse;
			}
			if (!*parse) {
				ast_log(LOG_WARNING, "No closing quote found in '%s'\n", tmp);
				return tmp;
			}
			parse++;
			continue;
		}
		if (first_bracket) {
			second_bracket = strchr(first_bracket + 1, '>');
			if (second_bracket) {
				*second_bracket = '\0';
				return first_bracket + 1;
			} else {
				ast_log(LOG_WARNING, "No closing bracket found in '%s'\n", tmp);
				return tmp;
			}
		}
		return tmp;
	}
}

/*! \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 */
static void realtime_update_peer(const char *peername, struct sockaddr_in *sin, const char *username, const char *fullcontact, int expirey)
{
	char port[10];
	char ipaddr[20];
	char regseconds[20];
	time_t nowtime;
	const char *fc = fullcontact ? "fullcontact" : NULL;
	
	time(&nowtime);
	nowtime += expirey;
	snprintf(regseconds, sizeof(regseconds), "%d", (int)nowtime);	/* Expiration time */
	ast_inet_ntoa(ipaddr, sizeof(ipaddr), sin->sin_addr);
	snprintf(port, sizeof(port), "%d", ntohs(sin->sin_port));
	
	ast_update_realtime("sippeers", "name", peername, "ipaddr", ipaddr,
		"port", port, "regseconds", regseconds,
		"username", username, fc, fullcontact, NULL); /* note fc _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;
	if (!ast_strlen_zero(global_regcontext)) {

		ast_copy_string(multi, S_OR(peer->regexten, peer->name), sizeof(multi));
		stringp = multi;
		while((ext = strsep(&stringp, "&"))) {
			if (onoff)
				ast_add_extension(global_regcontext, 1, ext, 1, NULL, NULL, "Noop",
						  ast_strdup(peer->name), free, "SIP");
			else
				ast_context_remove_extension(global_regcontext, ext, 1, NULL);
		}
	}
}

/*! \brief Destroy peer object from memory */
static void sip_destroy_peer(struct sip_peer *peer)
{
	if (option_debug > 2)
		ast_log(LOG_DEBUG, "Destroying SIP peer %s\n", peer->name);

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

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

	if (peer->chanvars) {
		ast_variables_destroy(peer->chanvars);
		peer->chanvars = NULL;
	}
	if (peer->expire > -1)
		ast_sched_del(sched, peer->expire);
	if (peer->pokeexpire > -1)
		ast_sched_del(sched, peer->pokeexpire);
	register_peer_exten(peer, FALSE);
	ast_free_ha(peer->ha);
	if (ast_test_flag(&peer->flags[1], SIP_PAGE2_SELFDESTRUCT))
		apeerobjs--;
	else if (ast_test_flag(&peer->flags[0], SIP_REALTIME))
		rpeerobjs--;
	else
		speerobjs--;
	clear_realm_authentication(peer->auth);
	peer->auth = NULL;
	if (peer->dnsmgr)
		ast_dnsmgr_release(peer->dnsmgr);
	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);