/*
 * Here we handle incoming INVITE requests in the UAS role: even though
 * we are strictly outbound, BulkVS servers will send us periodic
 * re-INVITEs as keepalives, and we have to play along.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <syslog.h>
#include "../include/out_routes.h"
#include "../libsip/parse.h"
#include "../libsip/uas_basic.h"
#include "../libsip/out_msg.h"
#include "call.h"

extern struct call *find_call_by_sip_id();

static void
invite_found_call(req, ess, sin, call)
	struct sip_pkt_rx *req;
	struct uas_parse_hdrs *ess;
	struct sockaddr_in *sin;
	struct call *call;
{
	struct sip_msg_out resp;
	int rc;

	switch (call->sip_state) {
	case SIP_STATE_INV_SENT:
	case SIP_STATE_100_RCVD:
		start_response_out_msg(&resp, "491 Outbound INVITE pending");
		break;
	case SIP_STATE_CONNECTED:
		start_response_out_msg(&resp, "200 OK");
		break;
	case SIP_STATE_CANCEL_SENT:
	case SIP_STATE_BYE_SENT:
	case SIP_STATE_ACCEPT_100:
	case SIP_STATE_ACCEPT_200:
	case SIP_STATE_ENDED:
		start_response_out_msg(&resp, "488 Call terminated");
		break;
	case SIP_STATE_MSG_SIZE_ERR:
		return;
	default:
		syslog(LOG_CRIT,
			"FATAL: invalid SIP state 0x%x on incoming re-INVITE",
			call->sip_state);
		exit(1);
	}
	rc = add_resp_basic_headers(&resp, ess, req->req_method);
	if (rc < 0) {
		syslog(LOG_ERR, "Re-INVITE response message size error");
		return;
	}
	out_msg_finish(&resp);
	sip_tx_packet(&resp, sin);
}

static void
invite_unknown_call(req, ess, sin)
	struct sip_pkt_rx *req;
	struct uas_parse_hdrs *ess;
	struct sockaddr_in *sin;
{
	struct sip_msg_out resp;
	int rc;

	start_response_out_msg(&resp, "405 This gateway is outbound only");
	rc = add_resp_basic_headers(&resp, ess, req->req_method);
	if (rc < 0)
		return;
	out_msg_finish(&resp);
	sip_tx_packet(&resp, sin);
}

void
handle_invite_req(req, ess, sin)
	struct sip_pkt_rx *req;
	struct uas_parse_hdrs *ess;
	struct sockaddr_in *sin;
{
	struct call *call;

	call = find_call_by_sip_id(ess->call_id);
	if (call)
		invite_found_call(req, ess, sin, call);
	else
		invite_unknown_call(req, ess, sin);
}