/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2008 Edwin Groothuis. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <netinet/in.h>
#include <arpa/tftp.h>

#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>

#include "tftp-utils.h"
#include "tftp-io.h"

/*
 * Default values, can be changed later via the TFTP Options
 */
int             timeoutpacket = TIMEOUT;
int             timeoutnetwork = MAX_TIMEOUTS * TIMEOUT;
int             maxtimeouts = MAX_TIMEOUTS;
uint16_t        segsize = SEGSIZE;
uint16_t        pktsize = SEGSIZE + 4;
uint16_t        windowsize = WINDOWSIZE;

int     acting_as_client;


/*
 * Set timeout values for packet reception. The idea is that you
 * get 'maxtimeouts' of 5 seconds between 'timeoutpacket' (i.e. the
 * first timeout) to 'timeoutnetwork' (i.e. the last timeout)
 */
int
settimeouts(int _timeoutpacket, int _timeoutnetwork, int _maxtimeouts __unused)
{
        int i;

        /* We cannot do impossible things */
        if (_timeoutpacket >= _timeoutnetwork)
                return (0);

        maxtimeouts = 0;
        i = _timeoutpacket;
        while (i < _timeoutnetwork || maxtimeouts < MIN_TIMEOUTS) {
                maxtimeouts++;
                i += 5;
        }

        timeoutpacket = _timeoutpacket;
        timeoutnetwork = i;
        return (1);
}

/* translate IPv4 mapped IPv6 address to IPv4 address */
void
unmappedaddr(struct sockaddr_in6 *sin6)
{
        struct sockaddr_in *sin4;
        u_int32_t addr;
        int port;

        if (sin6->sin6_family != AF_INET6 ||
            !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
                return;
        sin4 = (struct sockaddr_in *)sin6;
        memcpy(&addr, &sin6->sin6_addr.s6_addr[12], sizeof(addr));
        port = sin6->sin6_port;
        memset(sin4, 0, sizeof(struct sockaddr_in));
        sin4->sin_addr.s_addr = addr;
        sin4->sin_port = port;
        sin4->sin_family = AF_INET;
        sin4->sin_len = sizeof(struct sockaddr_in);
}

/* Get a field from a \0 separated string */
size_t
get_field(int peer, char *buffer, size_t size)
{
        char *cp = buffer;

        while (cp < buffer + size) {
                if (*cp == '\0') break;
                cp++;
        }
        if (*cp != '\0') {
                tftp_log(LOG_ERR, "Bad option - no trailing \\0 found");
                send_error(peer, EBADOP);
                exit(1);
        }
        return (cp - buffer + 1);
}

/*
 * Logging functions
 */
static int _tftp_logtostdout = 1;

void
tftp_openlog(const char *ident, int logopt, int facility)
{

        _tftp_logtostdout = (ident == NULL);
        if (_tftp_logtostdout == 0)
                openlog(ident, logopt, facility);
}

void
tftp_closelog(void)
{

        if (_tftp_logtostdout == 0)
                closelog();
}

void
tftp_log(int priority, const char *message, ...)
{
        va_list ap;
        int serrno;
        char *s;

        serrno = errno;
        va_start(ap, message);
        if (_tftp_logtostdout == 0) {
                vasprintf(&s, message, ap);
                syslog(priority, "%s", s);
        } else {
                vprintf(message, ap);
                printf("\n");
        }
        va_end(ap);
        errno = serrno;
}

/*
 * Packet types
 */
struct packettypes packettypes[] = {
        { RRQ,          "RRQ"   },
        { WRQ,          "WRQ"   },
        { DATA,         "DATA"  },
        { ACK,          "ACK"   },
        { ERROR,        "ERROR" },
        { OACK,         "OACK"  },
        { 0,            NULL    },
};

const char *
packettype(int type)
{
        static char failed[100];
        int i = 0;

        while (packettypes[i].name != NULL) {
                if (packettypes[i].value == type)
                        break;
                i++;
        }
        if (packettypes[i].name != NULL)
                return packettypes[i].name;
        sprintf(failed, "unknown (type: %d)", type);
        return (failed);
}

/*
 * Debugs
 */
int     debug = DEBUG_NONE;
struct debugs debugs[] = {
        { DEBUG_PACKETS,        "packet",       "Packet debugging"      },
        { DEBUG_SIMPLE,         "simple",       "Simple debugging"      },
        { DEBUG_OPTIONS,        "options",      "Options debugging"     },
        { DEBUG_ACCESS,         "access",       "TCPd access debugging" },
        { DEBUG_NONE,           NULL,           "No debugging"          },
};
unsigned int packetdroppercentage = 0;

int
debug_find(char *s)
{
        int i = 0;

        while (debugs[i].name != NULL) {
                if (strcasecmp(debugs[i].name, s) == 0)
                        break;
                i++;
        }
        return (debugs[i].value);
}

int
debug_finds(char *s)
{
        int i = 0;
        char *ps = s;

        while (s != NULL) {
                ps = strchr(s, ' ');
                if (ps != NULL)
                        *ps = '\0';
                i += debug_find(s);
                if (ps != NULL)
                        *ps = ' ';
                s = ps;
        }
        return (i);
}

const char *
debug_show(int d)
{
        static char s[100];
        size_t space = sizeof(s);
        int i = 0;

        s[0] = '\0';
        while (debugs[i].name != NULL) {
                if (d&debugs[i].value) {
                        if (s[0] != '\0')
                                strlcat(s, " ", space);
                        strlcat(s, debugs[i].name, space);
                }
                i++;
        }
        if (s[0] != '\0')
                return (s);
        return ("none");
}

/*
 * RP_
 */
struct rp_errors rp_errors[] = {
        { RP_TIMEOUT,           "Network timeout" },
        { RP_TOOSMALL,          "Not enough data bytes" },
        { RP_WRONGSOURCE,       "Invalid IP address of UDP port" },
        { RP_ERROR,             "Error packet" },
        { RP_RECVFROM,          "recvfrom() complained" },
        { RP_TOOBIG,            "Too many data bytes" },
        { RP_NONE,              NULL }
};

char *
rp_strerror(int error)
{
        static char s[100];
        size_t space = sizeof(s);
        int i = 0;

        while (rp_errors[i].desc != NULL) {
                if (rp_errors[i].error == error) {
                        strlcpy(s, rp_errors[i].desc, space);
                        space -= strlen(rp_errors[i].desc);
                }
                i++;
        }
        if (s[0] == '\0')
                sprintf(s, "unknown (error=%d)", error);
        return (s);
}

/*
 * Performance figures
 */

void
stats_init(struct tftp_stats *ts)
{

        ts->amount = 0;
        ts->rollovers = 0;
        ts->retries = 0;
        ts->blocks = 0;
        ts->amount = 0;
        gettimeofday(&(ts->tstart), NULL);
}

void
printstats(const char *direction, int verbose, struct tftp_stats *ts)
{
        double delta;   /* compute delta in 1/10's second units */

        delta = ((ts->tstop.tv_sec*10.)+(ts->tstop.tv_usec/100000)) -
                ((ts->tstart.tv_sec*10.)+(ts->tstart.tv_usec/100000));
        delta = delta/10.;      /* back to seconds */

        printf("%s %zu bytes during %.1f seconds in %u blocks",
            direction, ts->amount, delta, ts->blocks);

        if (ts->rollovers != 0)
                printf(" with %d rollover%s",
                    ts->rollovers, ts->rollovers != 1 ? "s" : "");

        if (verbose)
                printf(" [%.0f bits/sec]", (ts->amount*8.)/delta);
        putchar('\n');
}