/* cont_s.c - Send continue request to the server.
 * 
 * Copyright (C) 2010, 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"
#if defined(HAVE_OPENSSL_MD5_H) && defined(HAVE_LIBCRYPTO)
# include <openssl/md5.h>
#else
# include "md5.h"
#endif

/* this function sends a continue packet do TACACS+ server, asking
 * for validation of given password
 *
 * return value:
 *      0 : success
 *   <  0 : error status code, see LIBTAC_STATUS_...
 *         LIBTAC_STATUS_WRITE_ERR
 *         LIBTAC_STATUS_WRITE_TIMEOUT  (pending impl)
 *         LIBTAC_STATUS_ASSEMBLY_ERR
 */
int tac_cont_send_seq(int fd, const char *pass, int seq) {
	HDR *th; /* TACACS+ packet header */
	struct authen_cont tb; /* continue body */
	int pass_len, bodylength, w;
	int pkt_len = 0;
	int ret = 0;
	u_char *pkt = NULL;

	th = _tac_req_header(TAC_PLUS_AUTHEN, 1);

	/* set some header options */
	th->version = TAC_PLUS_VER_0;
	th->seq_no = seq; /* 1 = request, 2 = reply, 3 = continue, 4 = reply */
	th->encryption =
			tac_encryption ?
					TAC_PLUS_ENCRYPTED_FLAG : TAC_PLUS_UNENCRYPTED_FLAG;

	/* get size of submitted data */
	pass_len = strlen(pass);

	/* fill the body of message */
	tb.user_msg_len = htons(pass_len);
	tb.user_data_len = tb.flags = 0;

	/* fill body length in header */
	bodylength = TAC_AUTHEN_CONT_FIXED_FIELDS_SIZE + 0 + pass_len;

	th->datalength = htonl(bodylength);

	/* we can now write the header */
	w = write(fd, th, TAC_PLUS_HDR_SIZE);
	if (w < 0 || w < TAC_PLUS_HDR_SIZE) {
		TACSYSLOG(
				LOG_ERR, "%s: short write on header, wrote %d of %d: %m", __FUNCTION__, w, TAC_PLUS_HDR_SIZE);
		free(pkt);
		free(th);
		return LIBTAC_STATUS_WRITE_ERR;
	}

	/* build the packet */
	pkt = (u_char *) xcalloc(1, bodylength);

	bcopy(&tb, pkt + pkt_len, TAC_AUTHEN_CONT_FIXED_FIELDS_SIZE); /* packet body beginning */
	pkt_len += TAC_AUTHEN_CONT_FIXED_FIELDS_SIZE;
	bcopy(pass, pkt + pkt_len, pass_len); /* password */
	pkt_len += pass_len;

	/* pkt_len == bodylength ? */
	if (pkt_len != bodylength) {
		TACSYSLOG(
				LOG_ERR, "%s: bodylength %d != pkt_len %d", __FUNCTION__, bodylength, pkt_len);
		free(pkt);
		free(th);
		return LIBTAC_STATUS_ASSEMBLY_ERR;
	}

	/* encrypt the body */
	_tac_crypt(pkt, th);

	w = write(fd, pkt, pkt_len);
	if (w < 0 || w < pkt_len) {
		TACSYSLOG(
				LOG_ERR, "%s: short write on body, wrote %d of %d: %m", __FUNCTION__, w, pkt_len);
		ret = LIBTAC_STATUS_WRITE_ERR;
	}

	free(pkt);
	free(th);
	TACDEBUG(LOG_DEBUG, "%s: exit status=%d", __FUNCTION__, ret);
	return ret;
} /* tac_cont_send */