/* header.c - Create pre-filled header for TACACS+ request.
 * 
 * Copyright (C) 2010, Pawel Krawczyk <pawel.krawczyk@hush.com> and
 * Jeroen Nijhof <jeroen@jeroennijhof.nl>
 *
 * This program 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.
 *
 * This program 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 - see the file COPYING.
 *
 * See `CHANGES' file for revision history.
 */

#include "libtac.h"
#include "xalloc.h"
#include "magic.h"

/* Miscellaneous variables that are global, because we need
 * store their values between different functions and connections.
 */
/* Session identifier. */
int session_id;

/* Encryption flag. */
int tac_encryption = 0;

/* Pointer to TACACS+ shared secret string. */
/* note: tac_secret will point to tacplus_server[i].key */
const char *tac_secret = NULL;

/* TACACS+ shared login string. */
char tac_login[64]; /* default is PAP */

/* priv_lvl */
int tac_priv_lvl = TAC_PLUS_PRIV_LVL_MIN;

/* Authentication Method */
int tac_authen_method = TAC_PLUS_AUTHEN_METH_TACACSPLUS;

/* Service requesting authentication */
int tac_authen_service = TAC_PLUS_AUTHEN_SVC_PPP;

/* additional runtime flags */

int tac_debug_enable = 0;
int tac_readtimeout_enable = 0;

/* Returns pre-filled TACACS+ packet header of given type.
 * 1. you MUST fill th->datalength and th->version
 * 2. you MAY fill th->encryption
 * 3. you are responsible for freeing allocated header 
 * By default packet encryption is enabled. The version
 * field depends on the TACACS+ request type and thus it
 * cannot be predefined.
 */
HDR *_tac_req_header(u_char type, int cont_session) {
    HDR *th;

    th=(HDR *) xcalloc(1, TAC_PLUS_HDR_SIZE);

    /* preset some packet options in header */
    th->type=type;
    th->seq_no=1; /* always 1 for request */
    th->encryption=TAC_PLUS_ENCRYPTED_FLAG;
 
    /* make session_id from pseudo-random number */
    if (!cont_session)
        session_id = magic();
    th->session_id = htonl(session_id);

    return th;
}