/*
 * utils.c
 * ptunnel is licensed under the BSD license:
 *
 * Copyright (c) 2004-2011, Daniel Stoedle <daniels@cs.uit.no>,
 * Yellow Lemon Software. All rights reserved.
 *
 * Copyright (c) 2017-2019, Toni Uhlig <matzeton@googlemail.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * - Neither the name of the Yellow Lemon Software nor the names of its
 *   contributors may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Contacting the author:
 * You can get in touch with me, Daniel Stødle (that's the Norwegian letter oe,
 * in case your text editor didn't realize), here: <daniels@cs.uit.no>
 *
 * The official ptunnel website is here:
 * <http://www.cs.uit.no/~daniels/PingTunnel/>
 *
 * Note that the source code is best viewed with tabs set to 4 spaces.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#ifdef HAVE_BSD_STDLIB_H
#include <bsd/stdlib.h>
#endif

#ifndef WIN32
#include <errno.h>
#include <syslog.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#else
#include <ws2tcpip.h>
#endif
#include <sys/time.h>

#include "utils.h"
#include "options.h"

void pt_log(enum log_level level, const char * fmt, ...)
{
    va_list args;
    const char * header[] = {"[err]: ", "[inf]: ", "[evt]: ", "[vbs]: ", "[dbg]: ", "[xfr]: "};
#ifndef WIN32
    int syslog_levels[] = {LOG_ERR, LOG_NOTICE, LOG_NOTICE, LOG_INFO, LOG_DEBUG, LOG_DEBUG};
#endif /* !WIN32 */

    if (level <= opts.log_level) {
        va_start(args, fmt);
#ifndef WIN32
        if (opts.use_syslog) {
            char log[255];
            int header_len;
            header_len = snprintf(log, sizeof(log), "%s", header[level]);
            vsnprintf(log + header_len, sizeof(log) - header_len, fmt, args);
            syslog(syslog_levels[level], "%s", log);
        } else
#endif /* !WIN32 */
            fprintf(opts.log_file, "%s", header[level]), vfprintf(opts.log_file, fmt, args);
        va_end(args);
#ifndef WIN32
        if (opts.log_file != stdout && !opts.use_syslog)
#else
        if (opts.log_file != stdout)
#endif
            fflush(opts.log_file);
    }
}

double time_as_double(void)
{
    double result;
    struct timeval tt;

    gettimeofday(&tt, 0);
    result = (double)tt.tv_sec + ((double)tt.tv_usec / (double)10e5);
    return result;
}

int host_to_addr(const char * hostname, uint32_t * result)
{
    int ret;
    struct addrinfo * addrs = NULL;
    struct addrinfo hints;
    struct sockaddr_in * addr;

    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_INET;

    if ((ret = getaddrinfo(hostname, NULL, &hints, &addrs)) != 0)
        return ret;
    addr = (struct sockaddr_in *)addrs->ai_addr;
    *result = *(uint32_t *)&addr->sin_addr;
    freeaddrinfo(addrs);

    return 0;
}

#if 0
static const char hextab[] = "0123456789ABCDEF";

void print_hexstr(unsigned char *buf, size_t siz) {
	char *out = (char *) calloc(3, siz+1);
	unsigned char high, low;

	for (size_t i = 0; i < siz; ++i) {
		high = (buf[i] & 0xF0) >> 4;
		low  = buf[i] & 0x0F;
		out[i  ] = hextab[high];
		out[i+1] = hextab[low];
		out[i+2] = ' ';
	}

	printf("%s\n", out);
	free(out);
}
#endif

int pt_random(void)
{
#if defined(HAVE_ARC4RANDOM) || defined(__COVERITY__)
    return arc4random();
#else
#if defined(RNGDEV) && !defined(_WIN32)
    static int rng_fd = -1;
    ssize_t bytes_read;
    int rnd_val;
    if (rng_fd < 0) {
        rng_fd = open(RNGDEV, O_RDONLY);
        if (rng_fd < 0) {
            pt_log(kLog_error, "FATAL: Could not open random device '%s': %s\n", RNGDEV, strerror(errno));
            exit(EXIT_FAILURE);
        }
    }
    bytes_read = read(rng_fd, &rnd_val, sizeof rnd_val);
    if (bytes_read != sizeof rnd_val) {
        if (bytes_read < 0)
            pt_log(kLog_error, "FATAL: Read from random device failed: %s\n", strerror(errno));
        else
            pt_log(kLog_error, "FATAL: Read only %zd bytes (wanted %zd bytes)\n", bytes_read, sizeof rnd_val);
        exit(EXIT_FAILURE);
    }
    return rnd_val;
#else
    srand(time(0));
    return rand();
#endif
#endif
}