/*
 * Here we implement SIP INVITE response generation.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <syslog.h>
#include "../include/gsm48_const.h"
#include "../libsip/sdp.h"
#include "../libsip/out_msg.h"
#include "call.h"

extern struct in_addr sip_bind_ip;
extern unsigned sip_bind_port;
extern unsigned sip_linger_error;

fill_invite_resp_from_call(msg, call)
	struct sip_msg_out *msg;
	struct call *call;
{
	char cseq_str[32];
	int rc;

	rc = out_msg_add_header(msg, "From", call->invite_from);
	if (rc < 0)
		return rc;
	rc = out_msg_add_header(msg, "To", call->invite_to);
	if (rc < 0)
		return rc;
	rc = out_msg_add_header(msg, "Call-ID", call->sip_call_id);
	if (rc < 0)
		return rc;
	sprintf(cseq_str, "%u INVITE", call->invite_cseq);
	rc = out_msg_add_header(msg, "CSeq", cseq_str);
	if (rc < 0)
		return rc;
	return out_msg_add_header(msg, "Via", call->invite_via);
}

fill_invite_200_resp(msg, call)
	struct sip_msg_out *msg;
	struct call *call;
{
	char contact_str[80];
	struct sdp_gen sdp;
	int rc;

	start_response_out_msg(msg, "200 CONNECT");
	rc = fill_invite_resp_from_call(msg, call);
	if (rc < 0)
		return rc;
	sprintf(contact_str, "<sip:%s:%u;transport=udp>",
		inet_ntoa(sip_bind_ip), sip_bind_port);
	rc = out_msg_add_header(msg, "Contact", contact_str);
	if (rc < 0)
		return rc;
	rc = out_msg_add_header(msg, "Content-Type", "application/sdp");
	if (rc < 0)
		return rc;
	bzero(&sdp, sizeof sdp);
	sdp.conn_ip = call->pstn_rtp_local.sin_addr;
	sdp.conn_port = ntohs(call->pstn_rtp_local.sin_port);
	sdp.codec_mask = call->use_pcma ? SDP_CODEC_MASK_PCMA
					: SDP_CODEC_MASK_PCMU;
	sdp.session_id = (sdp.conn_port << 16) | call->sdp_addend;
	sdp.owner_ip = sip_bind_ip;
	return out_msg_finish_sdp(msg, &sdp);
}

void
signal_invite_ringing(call)
	struct call *call;
{
	struct sip_msg_out resp;
	int rc;

	start_response_out_msg(&resp, "180 Ringing");
	rc = fill_invite_resp_from_call(&resp, call);
	if (rc < 0) {
msg_size_err:	syslog(LOG_ERR, "INVITE 180 response length exceeded");
		call->sip_state = SIP_STATE_MSG_SIZE_ERR;
		call->overall_state = OVERALL_STATE_TEARDOWN;
		disconnect_mncc(call, GSM48_CAUSE_LOC_PRN_S_LU,
				GSM48_CC_CAUSE_INTERWORKING);
		disconnect_tmgw(call);
		sip_mark_end_time(call, sip_linger_error);
		return;
	}
	if (call->use_100rel) {
		rc = out_msg_add_header(&resp, "Require", "100rel");
		if (rc < 0)
			goto msg_size_err;
		rc = out_msg_add_header(&resp, "RSeq", "1");
		if (rc < 0)
			goto msg_size_err;
	}
	out_msg_finish(&resp);
	sip_tx_packet(&resp, &call->udp_sin);
	if (call->use_100rel) {
		call->sip_state = SIP_STATE_RINGING_REL;
		call->sip_tx_count = 1;
	} else
		call->sip_state = SIP_STATE_RINGING;
}

void
signal_invite_200(call)
	struct call *call;
{
	struct sip_msg_out resp;
	int rc;

	rc = fill_invite_200_resp(&resp, call);
	if (rc < 0) {
		syslog(LOG_ERR, "INVITE 200 response length exceeded");
		call->sip_state = SIP_STATE_MSG_SIZE_ERR;
		call->overall_state = OVERALL_STATE_TEARDOWN;
		disconnect_mncc(call, GSM48_CAUSE_LOC_PRN_S_LU,
				GSM48_CC_CAUSE_INTERWORKING);
		disconnect_tmgw(call);
		sip_mark_end_time(call, sip_linger_error);
		return;
	}
	sip_tx_packet(&resp, &call->udp_sin);
	call->sip_state = SIP_STATE_INVITE_200;
	call->sip_tx_count = 1;
}

void
signal_invite_error(call)
	struct call *call;
{
	struct sip_msg_out resp;
	int rc;

	start_response_out_msg(&resp, call->invite_fail);
	rc = fill_invite_resp_from_call(&resp, call);
	if (rc < 0) {
		syslog(LOG_ERR, "INVITE late error response length exceeded");
		call->sip_state = SIP_STATE_MSG_SIZE_ERR;
		sip_mark_end_time(call, sip_linger_error);
		transition_dead_sip(call);
		return;
	}
	out_msg_finish(&resp);
	sip_tx_packet(&resp, &call->udp_sin);
	call->sip_state = SIP_STATE_INVITE_ERR;
	call->sip_tx_count = 1;
}