/*
 * SIP message related functions
 *
 * 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
 */

/*!
 * \file
 * \brief SIP registrar module - SIP message related functions
 * \ingroup registrar
 */



#include "../../core/parser/hf.h"
#include "../../core/dprint.h"
#include "../../core/parser/parse_expires.h"
#include "../../core/ut.h"
#include "../../core/qvalue.h"
#include "../../core/rand/kam_rand.h"
#include "registrar.h"                     /* Module parameters */
#include "regtime.h"                     /* act_time */
#include "rerrno.h"
#include "sip_msg.h"
#include "config.h"
#include <stdlib.h>

static struct hdr_field* act_contact;

/* \brief
 * Return randomized expires between expires-range% and expires.
 * RFC allows only value less or equal to the one provided by UAC.
 */
static inline int randomize_expires( int expires, int range )
{
	int range_min;

	/* if no range is given just return expires */
	if(range == 0)
		return expires;

	range_min = expires - (float)range/100 * expires;

	return range_min + (float)(kam_rand()%100)/100 * ( expires - range_min );
}


/*! \brief
 * Return value of Expires header field
 * if the HF exists, if the HF doesn't exist,
 * returns -1;
 */
static inline int get_expires_hf(struct sip_msg* _m)
{
	exp_body_t* p;

	if (_m->expires) {
		p = (exp_body_t*)_m->expires->parsed;
		if (p->valid) {
			return p->val;
		}
	}
	return -1;
}


/*! \brief
 * Parse the whole message and bodies of all header fields
 * that will be needed by registrar
 */
int parse_message(struct sip_msg* _m)
{
	struct hdr_field* ptr;

	if (parse_headers(_m, HDR_EOH_F, 0) == -1) {
		rerrno = R_PARSE;
		LM_ERR("failed to parse headers\n");
		return -1;
	}

	if (!_m->to) {
		rerrno = R_TO_MISS;
		LM_ERR("To not found\n");
		return -2;
	}

	if (!_m->callid) {
		rerrno = R_CID_MISS;
		LM_ERR("Call-ID not found\n");
		return -3;
	}

	if (!_m->cseq) {
		rerrno = R_CS_MISS;
		LM_ERR("CSeq not found\n");
		return -4;
	}

	if (_m->expires && !_m->expires->parsed && (parse_expires(_m->expires) < 0)) {
		rerrno = R_PARSE_EXP;
		LM_ERR("failed to parse expires body\n");
		return -5;
	}

	if (_m->contact) {
		ptr = _m->contact;
		while(ptr) {
			if (ptr->type == HDR_CONTACT_T) {
				if (!ptr->parsed && (parse_contact(ptr) < 0)) {
					rerrno = R_PARSE_CONT;
					LM_ERR("failed to parse Contact body\n");
					return -6;
				}
			}
			ptr = ptr->next;
		}
	}

	return 0;
}


/*! \brief
 * Check if the originating REGISTER message was formed correctly
 * The whole message must be parsed before calling the function
 * _s indicates whether the contact was star
 */
int check_contacts(struct sip_msg* _m, int* _s)
{
	struct hdr_field* p;
	contact_t*  c;

	*_s = 0;
	/* Message without contacts is OK */
	if (_m->contact == 0) return 0;

	if (((contact_body_t*)_m->contact->parsed)->star == 1) {
		/* The first Contact HF is star */
		/* Expires must be zero */
		if (get_expires_hf(_m) != 0) {
			LM_WARN("expires must be 0 for star contact\n");
			rerrno = R_STAR_EXP;
			return 1;
		}

		/* Message must contain no contacts */
		if (((contact_body_t*)_m->contact->parsed)->contacts) {
			LM_WARN("star contact cannot be mixed with other contacts\n");
			rerrno = R_STAR_CONT;
			return 1;
		}

		/* Message must contain no other Contact HFs */
		p = _m->contact->next;
		while(p) {
			if (p->type == HDR_CONTACT_T) {
				LM_WARN("star contact cannot be mixed with other contacts\n");
				rerrno = R_STAR_CONT;
				return 1;
			}
			p = p->next;
		}

		*_s = 1;
	} else { /* The first Contact HF is not star */
		p = _m->contact;
		while(p) {
			if (p->type == HDR_CONTACT_T) {
				/* Message must contain no star Contact HF */
				if (((contact_body_t*)p->parsed)->star == 1) {
					LM_WARN("star contact cannot be mixed with other contacts\n");
					rerrno = R_STAR_CONT;
					return 1;
				}
				/* check also the length of all contacts */
				for(c=((contact_body_t*)p->parsed)->contacts ; c ; c=c->next) {
					if (c->uri.len > contact_max_size) {
						LM_WARN("contact uri is too long: [%.*s]\n", c->uri.len, c->uri.s);
						rerrno = R_CONTACT_LEN;
						return 1;
					}
					if (c->received && c->received->len>RECEIVED_MAX_SIZE) {
						LM_WARN("received attribute of contact is too long\n");
						rerrno = R_CONTACT_LEN;
						return 1;
					}
				}
			}
			p = p->next;
		}
	}

	return 0;
}


/*! \brief
 * Get the first contact in message
 */
contact_t* get_first_contact(struct sip_msg* _m)
{
	if (_m->contact == 0) return 0;

	act_contact = _m->contact;
	return (((contact_body_t*)_m->contact->parsed)->contacts);
}


/*! \brief
 * Get next contact in message
 */
contact_t* get_next_contact(contact_t* _c)
{
	struct hdr_field* p;
	if (_c->next == 0) {
		p = act_contact->next;
		while(p) {
			if (p->type == HDR_CONTACT_T) {
				act_contact = p;
				return (((contact_body_t*)p->parsed)->contacts);
			}
			p = p->next;
		}
		return 0;
	} else {
		return _c->next;
	}
}


/*! \brief
 * Calculate absolute expires value per contact as follows:
 * 1) If the contact has expires value, use the value. If it
 *    is not zero, add actual time to it
 * 2) If the contact has no expires parameter, use expires
 *    header field in the same way
 * 3) If the message contained no expires header field, use
 *    the default value
 */
void calc_contact_expires(struct sip_msg* _m, param_t* _ep, int* _e, int novariation)
{
	int range = 0;

	if (!_ep || !_ep->body.len) {
		*_e = get_expires_hf(_m);

		if ( *_e < 0 ) {
			*_e = cfg_get(registrar, registrar_cfg, default_expires);
			range = cfg_get(registrar, registrar_cfg, default_expires_range);
		} else {
			range = cfg_get(registrar, registrar_cfg, expires_range);
		}
	} else {
		if (str2int(&_ep->body, (unsigned int*)_e) < 0) {
			*_e = cfg_get(registrar, registrar_cfg, default_expires);
			range = cfg_get(registrar, registrar_cfg, default_expires_range);
		} else {
			range = cfg_get(registrar, registrar_cfg, expires_range);
		}
	}

	if ( *_e != 0 )
	{
		if (*_e < cfg_get(registrar, registrar_cfg, min_expires)) {
			*_e = cfg_get(registrar, registrar_cfg, min_expires);
		}

		if (!novariation) {
			*_e = randomize_expires( *_e, range );
			if (*_e < cfg_get(registrar, registrar_cfg, min_expires)) {
				*_e = cfg_get(registrar, registrar_cfg, min_expires);
			}
		}

		if (cfg_get(registrar, registrar_cfg, max_expires) && (*_e > cfg_get(registrar, registrar_cfg, max_expires))) {
			*_e = cfg_get(registrar, registrar_cfg, max_expires);
		}

		/* Convert to absolute value */
		*_e += act_time;
	}
}


/*! \brief
 * Calculate contact q value as follows:
 * 1) If xavp_cfg q has been defined, use it
 * 2) If q parameter exists in contact, use it
 * 3) If the parameter doesn't exist in contact, use the default value
 */
int calc_contact_q(param_t* _q, qvalue_t* _r)
{
	sr_xavp_t *vavp = NULL;
	str xqname = str_init("q");

	if (reg_xavp_cfg.s != NULL)
		vavp = xavp_get_child_with_ival(&reg_xavp_cfg, &xqname);

	if (vavp != NULL) {
		if ((vavp->val.v.i >= 0) && (vavp->val.v.i <= 1000)) {
			*_r = vavp->val.v.i;
			return 0;
		} else {
			rerrno = R_INV_Q; /* Invalid q parameter */
			LM_ERR("invalid q parameter\n");
			return -1;
		}
	}

	if (!_q || (_q->body.len == 0)) {
		*_r = cfg_get(registrar, registrar_cfg, default_q);
	} else {
		if (str2q(_r, _q->body.s, _q->body.len) < 0) {
			rerrno = R_INV_Q; /* Invalid q parameter */
			LM_ERR("invalid q parameter\n");
			return -1;
		}
	}

	return 0;
}
