/*
 * Copyright (c) 2014 - 2018 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Bill Yuan <bycn82@dragonflybsd.org>
 *
 * 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.
 * 3. Neither the name of The DragonFly Project 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 HOLDERS 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/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/wait.h>

#include <arpa/inet.h>
#include <ctype.h>
#include <dlfcn.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <netdb.h>
#include <pwd.h>
#include <sysexits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <timeconv.h>
#include <unistd.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/ethernet.h>

#include <net/ipfw3/ip_fw3.h>
#include <net/ipfw3_basic/ip_fw3_table.h>
#include <net/ipfw3_basic/ip_fw3_sync.h>
#include <net/ipfw3_basic/ip_fw3_basic.h>
#include <net/ipfw3_nat/ip_fw3_nat.h>
#include <net/dummynet3/ip_dummynet3.h>

#include "ipfw3.h"
#include "ipfw3nat.h"

extern int verbose;
extern int do_time;
extern int do_quiet;
extern int do_force;


void
nat_config_add(int ac, char **av)
{
        struct ioc_nat *ioc;
        struct in_addr *ip;
        int error, len = 0;
        char *id, buf[LEN_NAT_CMD_BUF];

        memset(buf, 0, LEN_NAT_CMD_BUF);
        ioc = (struct ioc_nat *)buf;

        NEXT_ARG;
        if (ac && isdigit(**av)) {
                id = *av;
                ioc->id = atoi(*av);
                if (ioc->id <= 0 || ioc->id > NAT_ID_MAX) {
                        errx(EX_DATAERR, "invalid nat id");
                }
        } else {
                errx(EX_DATAERR, "missing nat id");
        }
        len += LEN_IOC_NAT;

        NEXT_ARG;
        if (strncmp(*av, "ip", strlen(*av))) {
                errx(EX_DATAERR, "missing `ip'");
        }
        NEXT_ARG;
        ip = &ioc->ip;
        while (ac > 0){
                if (!inet_aton(*av, ip)) {
                        errx(EX_DATAERR, "bad ip addr `%s'", *av);
                }
                ioc->count++;
                len += LEN_IN_ADDR;
                ip++;
                NEXT_ARG;
        }

        error = do_set_x(IP_FW_NAT_ADD, ioc, len);
        if (error) {
                err(1, "do_set_x(%s)", "IP_FW_NAT_ADD");
        }

        /* show the rule after configured */
        int _ac = 2;
        char *_av[] = {"config", id};
        nat_config_get(_ac, _av);
}

void
nat_config_show(char *buf, int nbytes, int nat_id)
{
        struct ioc_nat *ioc;
        struct in_addr *ip;
        int n, len = 0;

        while (len < nbytes) {
                ioc = (struct ioc_nat *)(buf + len);
                if (nat_id == 0 || ioc->id == nat_id) {
                        printf("ipfw3 nat %u config ip", ioc->id);
                }
                ip = &ioc->ip;
                len += LEN_IOC_NAT;
                for (n = 0; n < ioc->count; n++) {
                        if (nat_id == 0 || ioc->id == nat_id) {
                                printf(" %s", inet_ntoa(*ip));
                        }
                        ip++;
                        len += LEN_IN_ADDR;
                }
                if (nat_id == 0 || ioc->id == nat_id) {
                        printf("\n");
                }
        }
}

void
nat_config_get(int ac, char **av)
{
        int nbytes, nalloc;
        int nat_id;
        uint8_t *data;

        nalloc = 1024;
        data = NULL;
        nat_id = 0;

        NEXT_ARG;
        if (ac == 1) {
                nat_id = strtoul(*av, NULL, 10);
        }

        nbytes = nalloc;
        while (nbytes >= nalloc) {
                nalloc = nalloc * 2;
                nbytes = nalloc;
                if ((data = realloc(data, nbytes)) == NULL) {
                        err(EX_OSERR, "realloc");
                }
                if (do_get_x(IP_FW_NAT_GET, data, &nbytes) < 0) {
                        err(EX_OSERR, "do_get_x(IP_FW_NAT_GET)");
                }
        }
        if (nbytes == 0) {
                exit(EX_OK);
        }
        nat_config_show(data, nbytes, nat_id);
}

void
nat_config_delete(int ac, char *av[])
{
        NEXT_ARG;
        int i = 0;
        if (ac > 0) {
                i = atoi(*av);
        }
        if (do_set_x(IP_FW_NAT_DEL, &i, sizeof(i)) == -1)
                errx(EX_USAGE, "NAT %d in use or not exists", i);
}

void
nat_state_show(int ac, char **av)
{
        int nbytes, nalloc;
        int nat_id;
        uint8_t *data;

        nalloc = 1024;
        data = NULL;

        NEXT_ARG;
        if (ac == 0)
                nat_id = 0;
        else
                nat_id = strtoul(*av, NULL, 10);

        nbytes = nalloc;
        while (nbytes >= nalloc) {
                nalloc = nalloc * 2;
                nbytes = nalloc;
                if ((data = realloc(data, nbytes)) == NULL) {
                        err(EX_OSERR, "realloc");
                }
                memcpy(data, &nat_id, sizeof(int));
                if (do_get_x(IP_FW_NAT_GET_RECORD, data, &nbytes) < 0) {
                        err(EX_OSERR, "do_get_x(IP_FW_NAT_GET_RECORD)");
                }
        }
        if (nbytes == 0)
                exit(EX_OK);

        struct ioc_nat_state *ioc;
        ioc =(struct ioc_nat_state *)data;
        int count = nbytes / LEN_IOC_NAT_STATE;
        int i;
        for (i = 0; i < count; i ++) {
                printf("%d %d", ioc->nat_id, ioc->cpu_id);
                if (ioc->proto == IPPROTO_ICMP) {
                        printf(" icmp");
                } else if (ioc->proto == IPPROTO_TCP) {
                        printf(" tcp");
                } else if (ioc->proto == IPPROTO_UDP) {
                        printf(" udp");
                }
                printf(" %s:%hu",inet_ntoa(ioc->src_addr),
                        htons(ioc->src_port));
                printf(" %s:%hu",inet_ntoa(ioc->alias_addr),
                        htons(ioc->alias_port));
                printf(" %s:%hu",inet_ntoa(ioc->dst_addr),
                        htons(ioc->dst_port));
                printf(" %c", ioc->direction? 'o' : 'i');
                printf(" %lld", (long long)ioc->life);
                printf("\n");
                ioc++;
        }
}

void
nat_config_flush(void)
{
        int cmd = IP_FW_NAT_FLUSH;
        if (!do_force) {
                int c;

                printf("Are you sure? [yn] ");
                fflush(stdout);
                do {
                        c = toupper(getc(stdin));
                        while (c != '\n' && getc(stdin) != '\n')
                                if (feof(stdin))
                                        return; /* and do not flush */
                } while (c != 'Y' && c != 'N');
                if (c == 'N')   /* user said no */
                        return;
        }
        if (do_set_x(cmd, NULL, 0) < 0 ) {
                errx(EX_USAGE, "NAT configuration in use");
        }
        if (!do_quiet) {
                printf("Flushed all nat configurations");
        }
}

void
nat_main(int ac, char **av)
{
        if (!strncmp(*av, "config", strlen(*av))) {
                nat_config_add(ac, av);
        } else if (!strncmp(*av, "flush", strlen(*av))) {
                nat_config_flush();
        } else if (!strncmp(*av, "show", strlen(*av))) {
                if (ac > 2 && isdigit(*(av[1]))) {
                        char *p = av[1];
                        av[1] = av[2];
                        av[2] = p;
                }
                NEXT_ARG;
                if (!strncmp(*av, "config", strlen(*av))) {
                        nat_config_get(ac, av);
                } else if (!strncmp(*av, "state", strlen(*av))) {
                        nat_state_show(ac,av);
                } else {
                        errx(EX_USAGE, "bad nat show command `%s'", *av);
                }
        } else if (!strncmp(*av, "delete", strlen(*av))) {
                nat_config_delete(ac, av);
        } else {
                errx(EX_USAGE, "bad ipfw nat command `%s'", *av);
        }
}