uac_fifo.c

用来作为linux中SIP SERVER,完成VOIP网络电话中服务器的功能

	dst EOL 				// ("." if no outbound server used)
							// must be used with dialogs/lr
	<EOL separated HFs>+	// From and To must be present at least;
							// dialog-apps must include tag in From
 							// (an ephemeral is appended otherwise)
							// and supply CSeq/CallId
	.[EOL]
	[body] 
	.EOL


	there is also the possibility to have server placed its
    hostname:portnumber in header fields -- just put double
	exclamation mark in any of the optional header fields
	(i.e., any but From/To/CallID,CSeq), they will be 
	substituted hn:pn

Example:

sc fifo t_uac_dlg MESSAGE sip:joe@192.168.2.1 \
	. \ # no outbound proxy
	'From:[e-mail];tagd=123'  \ # no to-tag -> ephemeral
	'To:[e-mail]' \
	'Foo: sip:user@!! '  \ # expansion here
	'CSEQ: 11 MESSAGE   ' \
	. \ # EoH
	.	# empty body
---
U 192.168.2.16:5060 -> 192.168.2.1:5060
MESSAGE sip:joe@192.168.2.1 SIP/2.0..
Via: SIP/2.0/UDP 192.168.2.16;branch=z9hG4bK760c.922ea6a1.0..
To: [e-mail]..
From: [e-mail];tagd=123;tag=5405e669bc2980663aed2624dc31396f-fa77..
CSeq: 11 MESSAGE..
Call-ID: e863bf56-22255@192.168.2.16..
Content-Length: 0..
User-Agent: Sip EXpress router (0.8.11pre4-tcp1-locking (i386/linux))..
Foo: sip:user@192.168.2.16:5060..
..


*/


/*
 * Make sure that the FIFO user created the message
 * correctly
 */
static inline int fifo_check_msg(struct sip_msg* msg, str* method, char* resp, str* body, 
				 int* fromtag, int *cseq_is, int* cseq, str* callid)
{
	struct to_body* parsed_from;
	struct cseq_body *parsed_cseq;
	int i;
	char c;

	if (body->len && !msg->content_type) {
		fifo_uac_error(resp, 400, "Content-Type missing");
		return -1;
	}

	if (body->len && msg->content_length) {
		fifo_uac_error(resp, 400, "Content-Length disallowed");
		return -2;
	}

	if (!msg->to) {
		fifo_uac_error(resp, 400, "To missing");
		return -3;
	}

	if (!msg->from) {
		fifo_uac_error(resp, 400, "From missing");
		return -4;
	}

	     /* we also need to know if there is from-tag and add it otherwise */
	if (parse_from_header(msg) < 0) {
		fifo_uac_error(resp, 400, "Error in From");
		return -5;
	}

	parsed_from = (struct to_body*)msg->from->parsed;
	*fromtag = parsed_from->tag_value.s && parsed_from->tag_value.len;

	*cseq = 0;
	if (msg->cseq && (parsed_cseq = get_cseq(msg))) {
		*cseq_is = 1;
		for (i = 0; i < parsed_cseq->number.len; i++) {
			c = parsed_cseq->number.s[i];
			if (c >= '0' && c <= '9' ) *cseq = (*cseq) * 10 + c - '0';
			else {
			        DBG("found non-numerical in CSeq: <%i>='%c'\n",(unsigned int)c,c);
				fifo_uac_error(resp, 400, "non-numerical CSeq");
				return -6;
			}
		}
		
		if (parsed_cseq->method.len != method->len 
		    || memcmp(parsed_cseq->method.s, method->s, method->len) !=0 ) {
			fifo_uac_error(resp, 400, "CSeq method mismatch");
			return -7;
		}
	} else {
		*cseq_is = 0;
	}

	if (msg->callid) {
		callid->s = msg->callid->body.s;
		callid->len = msg->callid->body.len;
	} else {
		callid->s = 0;
		callid->len = 0;
	}

	return 0;
}


#define FIFO_ROUTE_PREFIX "Route: "
#define FIFO_ROUTE_SEPARATOR ", "

static inline void print_routes(FILE* out, dlg_t* _d)
{
	rr_t* ptr;

	ptr = _d->hooks.first_route;

	if (ptr) {
		fprintf(out, FIFO_ROUTE_PREFIX);
	} else {
		fprintf(out, ".\n");
		return;
	}

	while(ptr) {
		fprintf(out, "%.*s", ptr->len, ptr->nameaddr.name.s);

		ptr = ptr->next;
		if (ptr) {
			fprintf(out, FIFO_ROUTE_SEPARATOR);
		}
	} 

	if (_d->hooks.last_route) {
		fprintf(out, FIFO_ROUTE_SEPARATOR "<");
		fprintf(out, "%.*s", _d->hooks.last_route->len, _d->hooks.last_route->s);
		fprintf(out, ">");
	}

	if (_d->hooks.first_route) {
		fprintf(out, CRLF);
	}
}


static inline int print_uris(FILE* out, struct sip_msg* reply)
{
	dlg_t* dlg;
	
	dlg = (dlg_t*)shm_malloc(sizeof(dlg_t));
	if (!dlg) {
		LOG(L_ERR, "print_uris(): No memory left\n");
		return -1;
	}

	memset(dlg, 0, sizeof(dlg_t));
	if (dlg_response_uac(dlg, reply) < 0) {
		LOG(L_ERR, "print_uris(): Error while creating dialog structure\n");
		free_dlg(dlg);
		return -2;
	}

	if (dlg->state != DLG_CONFIRMED) {
		fprintf(out, ".\n.\n.\n");
		free_dlg(dlg);
		return 0;
	}

	if (dlg->hooks.request_uri->s) {	
		fprintf(out, "%.*s\n", dlg->hooks.request_uri->len, dlg->hooks.request_uri->s);
	} else {
		fprintf(out, ".\n");
	}
	if (dlg->hooks.next_hop->s) {
		fprintf(out, "%.*s\n", dlg->hooks.next_hop->len, dlg->hooks.next_hop->s);
	} else {
		fprintf(out, ".\n");
	}
	print_routes(out, dlg);
	free_dlg(dlg);
	return 0;
}


static void fifo_callback( struct cell *t, int type, struct tmcb_params *ps )
{
	
	char *filename;
	FILE* f;
	str text;

	DBG("!!!!! ref_counter: %d\n", t->ref_count);

	DBG("DEBUG: fifo UAC completed with status %d\n", ps->code);
	if (!*ps->param) {
		LOG(L_INFO, "INFO: fifo UAC completed with status %d\n", ps->code);
		return;
	}

	filename=(char *)(*ps->param);
	if (ps->rpl==FAKED_REPLY) {
		get_reply_status( &text, ps->rpl, ps->code);
		if (text.s==0) {
			LOG(L_ERR, "ERROR: fifo_callback: get_reply_status failed\n");
			fifo_reply( filename,
				"500 fifo_callback: get_reply_status failed\n");
			goto done;
		}
		fifo_reply(filename, "%.*s\n", text.len, text.s );
		pkg_free(text.s);
	} else {
		text.s = ps->rpl->first_line.u.reply.reason.s;
		text.len = ps->rpl->first_line.u.reply.reason.len;

		f = open_reply_pipe(filename);
		if (!f) return;
		fprintf(f, "%d %.*s\n", ps->rpl->first_line.u.reply.statuscode, text.len, text.s);
		print_uris(f, ps->rpl);
		fprintf(f, "%s\n", ps->rpl->headers->name.s);
		fclose(f);
	}
	DBG("DEBUG: fifo_callback successfully completed\n");
done:
	shm_free(filename);
}


int fifo_uac(FILE *stream, char *response_file)
{
	str method, ruri, nexthop, headers, body, hfb, callid;
	struct sip_uri puri, pnexthop;
	struct sip_msg faked_msg;
	int ret, sip_error, err_ret;
	int fromtag, cseq_is, cseq;
	struct cb_data;
	char err_buf[MAX_REASON_LEN];
	char* shm_file;
	dlg_t dlg;

	if (fifo_get_method(stream, response_file, &method) < 0) return 1;
	if (fifo_get_ruri(stream, response_file, &ruri, &puri) < 0) return 1;
	if (fifo_get_nexthop(stream, response_file, &nexthop, &pnexthop) < 0) return 1;
	if (fifo_get_headers(stream, response_file, &headers) < 0) return 1;

	/* use SIP parser to look at what is in the FIFO request */
	memset(&faked_msg, 0, sizeof(struct sip_msg));
	faked_msg.len = headers.len; 
	faked_msg.buf = faked_msg.unparsed = headers.s;
	if (parse_headers(&faked_msg, HDR_EOH, 0) == -1 ) {
		DBG("DEBUG: fifo_uac: parse_headers failed\n");
		fifo_uac_error(response_file, 400, "HFs unparseable");
		goto error;
	}
	DBG("DEBUG: fifo_uac: parse_headers succeeded\n");

	if (fifo_get_body(stream, response_file, &body) < 0) goto error;
	
	     /* at this moment, we collected all the things we got, let's
	      * verify user has not forgotten something */
	if (fifo_check_msg(&faked_msg, &method, response_file, &body, &fromtag, 
			   &cseq_is, &cseq, &callid) < 0) goto error;

	hfb.s = get_hfblock(nexthop.len ? &nexthop : &ruri, 
			    faked_msg.headers, &hfb.len, PROTO_UDP);
	if (!hfb.s) {
		fifo_uac_error(response_file, 500, "no mem for hf block");
		goto error;
	}

	DBG("DEBUG: fifo_uac: EoL -- proceeding to transaction creation\n");

	memset(&dlg, 0, sizeof(dlg_t));
	     /* Fill in Call-ID, use given Call-ID if
	      * present and generate it if not present
	      */
	if (callid.s && callid.len) dlg.id.call_id = callid;
	else generate_callid(&dlg.id.call_id);
	
	     /* We will not fill in dlg->id.rem_tag because
	      * if present it will be printed within To HF
	      */
	
	     /* Generate fromtag if not present */
	if (!fromtag) {
		generate_fromtag(&dlg.id.loc_tag, &dlg.id.call_id);
	}

	     /* Fill in CSeq */
	if (cseq_is) dlg.loc_seq.value = cseq;
	else dlg.loc_seq.value = DEFAULT_CSEQ;
	dlg.loc_seq.is_set = 1;

	dlg.loc_uri = faked_msg.from->body;
	dlg.rem_uri = faked_msg.to->body;
	dlg.hooks.request_uri = &ruri;
	dlg.hooks.next_hop = (nexthop.len ? &nexthop : &ruri);

#ifdef XL_DEBUG
	print_dlg(stderr, &dlg);
#endif

	/* we got it all, initiate transaction now! */
	if (fifo_cbp(&shm_file, response_file) < 0) goto error01;

	ret = t_uac(&method, &hfb, &body, &dlg, fifo_callback, shm_file);

	if (ret <= 0) {
		err_ret = err2reason_phrase(ret, &sip_error, err_buf,
			sizeof(err_buf), "FIFO/UAC") ;
		if (err_ret > 0 )
		{
			fifo_uac_error(response_file, sip_error, err_buf);
		} else {
			fifo_uac_error(response_file, 500, "FIFO/UAC error");
		}
	}
	
 error01:
	pkg_free(hfb.s);
	
 error:
	     /* free_sip_msg(&faked_msg); */
	if (faked_msg.headers) free_hdr_field_lst(faked_msg.headers);
	return 1;
}