/*
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "../../globals.h"
#include "../../forward.h"
#include "../../dprint.h"
#include "../../md5utils.h"
#include "../../msg_translator.h"
#include "../../udp_server.h"
#include "../../timer.h"
#include "../../mem/mem.h"
#include "../../mem/shm_mem.h"
#include "../../crc.h"
#include "../../dset.h"
#include "../../data_lump_rpl.h"
#include "../../action.h"
#include "../../config.h"
#include "../../tags.h"
#include "../../parser/parse_to.h"
#include "../../route.h"
#include "../../receive.h"
#include "../../onsend.h"
#include "sl_stats.h"
#include "sl_funcs.h"
#include "sl.h"


/* to-tag including pre-calculated and fixed part */
static char           sl_tag_buf[TOTAG_VALUE_LEN];
static str            sl_tag = {sl_tag_buf,TOTAG_VALUE_LEN};
/* from here, the variable prefix begins */
static char           *tag_suffix;
/* if we for this time did not send any stateless reply,
   we do not filter */
static unsigned int  *sl_timeout;

static int _sl_filtered_ack_route = -1; /* default disabled */

static int _sl_evrt_local_response = -1; /* default disabled */

/*!
 * lookup sl event routes
 */
void sl_lookup_event_routes(void)
{
	_sl_filtered_ack_route=route_lookup(&event_rt, "sl:filtered-ack");
	if (_sl_filtered_ack_route>=0 && event_rt.rlist[_sl_filtered_ack_route]==0)
		_sl_filtered_ack_route=-1; /* disable */

	 _sl_evrt_local_response = route_lookup(&event_rt, "sl:local-response");
	if (_sl_evrt_local_response>=0
			&& event_rt.rlist[_sl_evrt_local_response]==NULL)
		_sl_evrt_local_response = -1;
}

/*!
 * init sl internal structures
 */
int sl_startup()
{
	init_tags( sl_tag.s, &tag_suffix,
			"SER-stateless",
			SL_TOTAG_SEPARATOR );

	/*timeout*/
	sl_timeout = (unsigned int*)shm_malloc(sizeof(unsigned int));
	if (!sl_timeout)
	{
		LOG(L_ERR,"ERROR:sl_startup: no more free memory!\n");
		return -1;
	}
	*(sl_timeout)=get_ticks();

	return 1;
}

/*!
 * free sl internal structures
 */
int sl_shutdown()
{
	if (sl_timeout)
		shm_free(sl_timeout);
	return 1;
}

/*!
 * get the To-tag for stateless reply
 */
int sl_get_reply_totag(struct sip_msg *msg, str *totag)
{
	if(msg==NULL || totag==NULL)
		return -1;
	calc_crc_suffix(msg, tag_suffix);
	*totag = sl_tag;
	return 1;
}


/*!
 * helper function for stateless reply
 */
int sl_reply_helper(struct sip_msg *msg, int code, char *reason, str *tag)
{
	str buf = {0, 0};
	str dset = {0, 0};
	struct dest_info dst;
	struct bookmark dummy_bm;
	int backup_mhomed, ret;
	str text;

	int backup_rt;
	struct run_act_ctx ctx;
	struct sip_msg pmsg;

	if (msg->first_line.u.request.method_value==METHOD_ACK)
		goto error;

	init_dest_info(&dst);
	if (reply_to_via) {
		if (update_sock_struct_from_via(&dst.to, msg, msg->via1 )==-1)
		{
			LOG(L_ERR, "ERROR: sl_reply_helper: cannot lookup reply dst: %s\n",
				msg->via1->host.s);
			goto error;
		}
	} else update_sock_struct_from_ip(&dst.to, msg);

	/* if that is a redirection message, dump current message set to it */
	if (code>=300 && code<400) {
		dset.s=print_dset(msg, &dset.len);
		if (dset.s) {
			add_lump_rpl(msg, dset.s, dset.len, LUMP_RPL_HDR);
		}
	}

	text.s = reason;
	text.len = strlen(reason);

	/* add a to-tag if there is a To header field without it */
	if ( 	/* since RFC3261, we append to-tags anywhere we can, except
		 * 100 replies */
       		/* msg->first_line.u.request.method_value==METHOD_INVITE && */
		code>=180 &&
		(msg->to || (parse_headers(msg,HDR_TO_F, 0)!=-1 && msg->to))
		&& (get_to(msg)->tag_value.s==0 || get_to(msg)->tag_value.len==0) ) 
	{
		if(tag!=NULL && tag->s!=NULL) {
			buf.s = build_res_buf_from_sip_req(code, &text, tag,
						msg, (unsigned int*)&buf.len, &dummy_bm);
		} else {
			calc_crc_suffix( msg, tag_suffix );
			buf.s = build_res_buf_from_sip_req(code, &text, &sl_tag, msg,
					(unsigned int*)&buf.len, &dummy_bm);
		}
	} else {
		buf.s = build_res_buf_from_sip_req(code, &text, 0, msg,
				(unsigned int*)&buf.len, &dummy_bm);
	}
	if (!buf.s)
	{
		DBG("DEBUG: sl_reply_helper: response building failed\n");
		goto error;
	}
	
	sl_run_callbacks(SLCB_REPLY_READY, msg, code, reason, &buf, &dst);

	/* supress multhoming support when sending a reply back -- that makes sure
	   that replies will come from where requests came in; good for NATs
	   (there is no known use for mhomed for locally generated replies;
	    note: forwarded cross-interface replies do benefit of mhomed!
	*/
	backup_mhomed=mhomed;
	mhomed=0;
	/* use for sending the received interface -bogdan*/
	dst.proto=msg->rcv.proto;
	dst.send_sock=msg->rcv.bind_address;
	dst.id=msg->rcv.proto_reserved1;
#ifdef USE_COMP
	dst.comp=msg->via1->comp_no;
#endif
	dst.send_flags=msg->rpl_send_flags;
	ret = msg_send(&dst, buf.s, buf.len);
	mhomed=backup_mhomed;

	if (unlikely(_sl_evrt_local_response >= 0))
	{
		if (likely(build_sip_msg_from_buf(&pmsg, buf.s, buf.len,
				inc_msg_no()) == 0))
		{
			char *tmp = NULL;
			struct onsend_info onsnd_info;

			onsnd_info.to=&dst.to;
			onsnd_info.send_sock=dst.send_sock;
			onsnd_info.buf=buf.s;
			onsnd_info.len=buf.len;
			p_onsend=&onsnd_info;

			if (unlikely(!IS_SIP(msg)))
			{
				/* This is an HTTP reply...  So fudge in a CSeq into the parsed message
 				   message structure so that $rm will work in the route */
				struct hdr_field *hf;
				struct cseq_body *cseqb;
				char *tmp2;
				int len;

				if ((hf = (struct hdr_field *) pkg_malloc(sizeof(struct hdr_field))) == NULL)
				{
					LM_ERR("out of package memory\n");
					goto event_route_error;
				}

				if ((cseqb = (struct cseq_body *) pkg_malloc(sizeof(struct cseq_body))) == NULL)
				{
					LM_ERR("out of package memory\n");
					pkg_free(hf);
					goto event_route_error;
				}

				if ((tmp = (char *) pkg_malloc(sizeof(char) * (msg->first_line.u.request.method.len + 5))) == NULL)
				{
					LM_ERR("out of package memory\n");
					pkg_free(cseqb);
					pkg_free(hf);
					goto event_route_error;
				}

				memset(hf, 0, sizeof(struct hdr_field));
				memset(cseqb, 0, sizeof(struct cseq_body));

				len = sprintf(tmp, "0 %.*s\r\n", msg->first_line.u.request.method.len, msg->first_line.u.request.method.s);
				tmp2 = parse_cseq(tmp, &tmp[len], cseqb);

				hf->type = HDR_CSEQ_T;
				hf->body.s = tmp;
				hf->body.len = tmp2 - tmp;
				hf->parsed = cseqb;

				pmsg.parsed_flag|=HDR_CSEQ_F;
				pmsg.cseq = hf;
				if (pmsg.last_header==0) {
					pmsg.headers=hf;
					pmsg.last_header=hf;
				} else {
					pmsg.last_header->next=hf;
					pmsg.last_header=hf;
				}
			}

			backup_rt = get_route_type();
			set_route_type(LOCAL_ROUTE);
			init_run_actions_ctx(&ctx);
			run_top_route(event_rt.rlist[_sl_evrt_local_response], &pmsg, 0);
			set_route_type(backup_rt);
			p_onsend=0;

			if (tmp != NULL)
				pkg_free(tmp);

event_route_error:
			free_sip_msg(&pmsg);
		}
	}

	pkg_free(buf.s);

	if (ret<0) {
		goto error;
	}
	
	*(sl_timeout) = get_ticks() + SL_RPL_WAIT_TIME;

	update_sl_stats(code);
	return 1;

error:
	update_sl_failures();
	return -1;
}

/*! wrapper of sl_reply_helper - reason is charz, tag is null */
int sl_send_reply(struct sip_msg *msg, int code, char *reason)
{
	return sl_reply_helper(msg, code, reason, 0);
}

/*! wrapper of sl_reply_helper - reason is str, tag is null */
int sl_send_reply_str(struct sip_msg *msg, int code, str *reason)
{
	char *r;
	int ret;

	if(reason->s[reason->len-1]=='\0') {
		r = reason->s;
	} else {
		r = as_asciiz(reason);
		if (r == NULL)
		{
			LM_ERR("no pkg for reason phrase\n");
			return -1;
		}
	}

	ret = sl_reply_helper(msg, code, r, 0);

    if (r!=reason->s) pkg_free(r);
	return ret;
}

/*! wrapper of sl_reply_helper - reason is str, tag is str */
int sl_send_reply_dlg(struct sip_msg *msg, int code, str *reason, str *tag)
{
	char *r;
	int ret;

	if(reason->s[reason->len-1]=='\0') {
		r = reason->s;
	} else {
		r = as_asciiz(reason);
		if (r == NULL)
		{
			LM_ERR("no pkg for reason phrase\n");
			return -1;
		}
	}

	ret = sl_reply_helper(msg, code, r, tag);

    if (r!=reason->s) pkg_free(r);
	return ret;
}

int sl_reply_error(struct sip_msg *msg )
{
	static char err_buf[MAX_REASON_LEN];
	int sip_error;
	int ret;

	ret=err2reason_phrase( prev_ser_error, &sip_error, 
		err_buf, sizeof(err_buf), "SL");
	if (ret>0) {
	        sl_send_reply( msg, sip_error, err_buf );
		LOG(L_ERR, "ERROR: sl_reply_error used: %s\n", 
			err_buf );
		return 1;
	} else {
		LOG(L_ERR, "ERROR: sl_reply_error: err2reason failed\n");
		return -1;
	}
}



/* Returns:
    0  : ACK to a local reply
    -1 : error
    1  : is not an ACK  or a non-local ACK
*/
int sl_filter_ACK(struct sip_msg *msg, unsigned int flags, void *bar )
{
	str *tag_str;

	if (msg->first_line.u.request.method_value!=METHOD_ACK)
		goto pass_it;

	/*check the timeout value*/
	if ( *(sl_timeout)<= get_ticks() )
	{
		DBG("DEBUG : sl_filter_ACK: to late to be a local ACK!\n");
		goto pass_it;
	}

	/*force to parse to header -> we need it for tag param*/
	if (parse_headers( msg, HDR_TO_F, 0 )==-1)
	{
		LOG(L_ERR,"ERROR : SL_FILTER_ACK: unable to parse To header\n");
		return -1;
	}

	if (msg->to) {
		tag_str = &(get_to(msg)->tag_value);
		if ( tag_str->len==TOTAG_VALUE_LEN )
		{
			/* calculate the variable part of to-tag */	
			calc_crc_suffix(msg, tag_suffix);
			/* test whether to-tag equal now */
			if (memcmp(tag_str->s,sl_tag.s,sl_tag.len)==0) {
				LM_DBG("SL local ACK found -> dropping it!\n" );
				update_sl_filtered_acks();
				sl_run_callbacks(SLCB_ACK_FILTERED, msg, 0, 0, 0, 0);
				if(unlikely(_sl_filtered_ack_route>=0)) {
					run_top_route(event_rt.rlist[_sl_filtered_ack_route],
							msg, 0);
				}
				return 0;
			}
		}
	}

pass_it:
	return 1;
}

/**
 * SL callbacks handling
 */

static sl_cbelem_t *_sl_cbelem_list = NULL;
static int _sl_cbelem_mask = 0;

void sl_destroy_callbacks_list(void)
{
	sl_cbelem_t *p1;
	sl_cbelem_t *p2;

	p1 = _sl_cbelem_list;
	while(p1) {
		p2 = p1;
		p1 = p1->next;
		pkg_free(p2);
	}
}

int sl_register_callback(sl_cbelem_t *cbe)
{
	sl_cbelem_t *p1;

	if(cbe==NULL) {
		LM_ERR("invalid parameter\n");
		return -1;
	}
	p1 = (sl_cbelem_t*)pkg_malloc(sizeof(sl_cbelem_t));

	if(p1==NULL) {
		LM_ERR("no more pkg\n");
		return -1;
	}

	memcpy(p1, cbe, sizeof(sl_cbelem_t));
	p1->next = _sl_cbelem_list;
	_sl_cbelem_list = p1;
	_sl_cbelem_mask |= cbe->type;

	return 0;
}

void sl_run_callbacks(unsigned int type, struct sip_msg *req,
		int code, char *reason, str *reply, struct dest_info *dst)
{
	sl_cbp_t param;
	sl_cbelem_t *p1;
	static str sreason;

	if(likely((_sl_cbelem_mask&type)==0))
		return;

	/* memset(&cbp, 0, sizeof(sl_cbp_t)); */
	param.type   = type;
	param.req    = req;
	param.code   = code;
	sreason.s    = reason;
	if(reason)
		sreason.len  = strlen(reason);
	else
		sreason.len  = 0;
	param.reason = &sreason;
	param.reply  = reply;
	param.dst    = dst;

	for(p1=_sl_cbelem_list; p1; p1=p1->next) {
		if (p1->type&type) {
			LM_DBG("execute callback for event type %d\n", type);
			param.cbp = p1->cbp;
			p1->cbf(&param);
		}
	}
}