/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Gleb Smirnoff <glebius@FreeBSD.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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE 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 THE 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/param.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/pfil.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int dev;

static const char * const typenames[] = {
        [PFIL_TYPE_IP4] = "IPv4",
        [PFIL_TYPE_IP6] = "IPv6",
        [PFIL_TYPE_ETHERNET] = "Ethernet",
};

static void listheads(int argc, char *argv[]);
static void listhooks(int argc, char *argv[]);
static void hook(int argc, char *argv[]);
static void help(void);

static const struct cmd {
        const char      *cmd_name;
        void            (*cmd_func)(int argc, char *argv[]);
} cmds[] = {
        { "heads",      listheads },
        { "hooks",      listhooks },
        { "link",       hook },
        { "unlink",     hook },
        { NULL,         NULL },
};

int
main(int argc __unused, char *argv[] __unused)
{
        int cmd = -1;

        if (--argc == 0)
                help();
        argv++;

        for (int i = 0; cmds[i].cmd_name != NULL; i++)
                if (!strncmp(argv[0], cmds[i].cmd_name, strlen(argv[0]))) {
                        if (cmd != -1)
                                errx(1, "ambiguous command: %s", argv[0]);
                        cmd = i;
                }
        if (cmd == -1)
                errx(1, "unknown command: %s", argv[0]);

        dev = open("/dev/" PFILDEV, O_RDWR);
        if (dev == -1)
                err(1, "open(%s)", "/dev/" PFILDEV);

        (*cmds[cmd].cmd_func)(argc, argv);

        return (0);
}

static void
help(void)
{

        fprintf(stderr, "usage: %s (heads|hooks|link|unlink)\n", getprogname());
        exit(0);
}

static void
listheads(int argc __unused, char *argv[] __unused)
{
        struct pfilioc_list plh;
        u_int nheads, nhooks, i;
        int j, h;

        plh.pio_nheads = 0;
        plh.pio_nhooks = 0;
        if (ioctl(dev, PFILIOC_LISTHEADS, &plh) != 0)
                err(1, "ioctl(PFILIOC_LISTHEADS)");

retry:
        plh.pio_heads = calloc(plh.pio_nheads, sizeof(struct pfilioc_head));
        if (plh.pio_heads == NULL)
                err(1, "malloc");
        plh.pio_hooks = calloc(plh.pio_nhooks, sizeof(struct pfilioc_hook));
        if (plh.pio_hooks == NULL)
                err(1, "malloc");

        nheads = plh.pio_nheads;
        nhooks = plh.pio_nhooks;

        if (ioctl(dev, PFILIOC_LISTHEADS, &plh) != 0)
                err(1, "ioctl(PFILIOC_LISTHEADS)");

        if (plh.pio_nheads > nheads || plh.pio_nhooks > nhooks) {
                free(plh.pio_heads);
                free(plh.pio_hooks);
                goto retry;
        }

#define FMTHD   "%16s %8s\n"
#define FMTHK   "%29s %16s:%s\n"
        printf("%16s %8s %3s %16s\n", "Intercept point", "Type", "Dir", "Hook");
        for (i = 0, h = 0; i < plh.pio_nheads; i++) {
                printf(FMTHD, plh.pio_heads[i].pio_name,
                    typenames[plh.pio_heads[i].pio_type]);
                for (j = 0; j < plh.pio_heads[i].pio_nhooksin; j++, h++)
                        printf(FMTHK, "In", plh.pio_hooks[h].pio_module,
                            plh.pio_hooks[h].pio_ruleset);
                for (j = 0; j < plh.pio_heads[i].pio_nhooksout; j++, h++)
                        printf(FMTHK, "Out", plh.pio_hooks[h].pio_module,
                            plh.pio_hooks[h].pio_ruleset);
        }
}

static void
listhooks(int argc __unused, char *argv[] __unused)
{
        struct pfilioc_list plh;
        u_int nhooks, i;

        plh.pio_nhooks = 0;
        if (ioctl(dev, PFILIOC_LISTHOOKS, &plh) != 0)
                err(1, "ioctl(PFILIOC_LISTHOOKS)");
retry:
        plh.pio_hooks = calloc(plh.pio_nhooks, sizeof(struct pfilioc_hook));
        if (plh.pio_hooks == NULL)
                err(1, "malloc");

        nhooks = plh.pio_nhooks;

        if (ioctl(dev, PFILIOC_LISTHOOKS, &plh) != 0)
                err(1, "ioctl(PFILIOC_LISTHOOKS)");

        if (plh.pio_nhooks > nhooks) {
                free(plh.pio_hooks);
                goto retry;
        }

        printf("%16s %16s %8s\n", "Hook", "", "Type");
        for (i = 0; i < plh.pio_nhooks; i++) {
                printf("%16s:%-16s %8s\n", plh.pio_hooks[i].pio_module,
                    plh.pio_hooks[i].pio_ruleset,
                    typenames[plh.pio_hooks[i].pio_type]);
        }
}

static void
hook(int argc, char *argv[])
{
        struct pfilioc_link req;
        int c;
        char *ruleset;

        if (argv[0][0] == 'u')
                req.pio_flags = PFIL_UNLINK;
        else
                req.pio_flags = 0;

        while ((c = getopt(argc, argv, "ioa")) != -1)
                switch (c) {
                case 'i':
                        req.pio_flags |= PFIL_IN;
                        break;
                case 'o':
                        req.pio_flags |= PFIL_OUT;
                        break;
                case 'a':
                        req.pio_flags |= PFIL_APPEND;
                        break;
                default:
                        help();
                }

        if (!PFIL_DIR(req.pio_flags))
                help();

        argc -= optind;
        argv += optind;

        if (argc != 2)
                help();

        /* link mod:ruleset head */
        if ((ruleset = strchr(argv[0], ':')) == NULL)
                help();
        *ruleset = '\0';
        ruleset++;

        strlcpy(req.pio_name, argv[1], sizeof(req.pio_name));
        strlcpy(req.pio_module, argv[0], sizeof(req.pio_module));
        strlcpy(req.pio_ruleset, ruleset, sizeof(req.pio_ruleset));

        if (ioctl(dev, PFILIOC_LINK, &req) != 0)
                err(1, "ioctl(PFILIOC_LINK)");
}