xtables-addons/extensions/libxt_RAWSNAT.c

/*
 *	"RAWNAT" target extension for iptables
 *	Copyright © Jan Engelhardt, 2008 - 2009
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License; either
 *	version 2 of the License, or any later version, as published by the
 *	Free Software Foundation.
 */
#include <netinet/in.h>
#include <getopt.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <xtables.h>
#include <linux/netfilter.h>
#include "xt_RAWNAT.h"
#include "compat_user.h"

enum {
	FLAGS_TO = 1 << 0,
};

static const struct option rawsnat_tg_opts[] = {
	{.name = "to-source", .has_arg = true, .val = 't'},
	{},
};

static void rawsnat_tg_help(void)
{
	printf(
"RAWSNAT target options:\n"
"    --to-source addr[/mask]    Address or network to map to\n"
);
}

static int
rawsnat_tg4_parse(int c, char **argv, int invert, unsigned int *flags,
                  const void *entry, struct xt_entry_target **target)
{
	struct xt_rawnat_tginfo *info = (void *)(*target)->data;
	struct in_addr *a;
	unsigned int mask;
	char *end;

	switch (c) {
	case 't':
		info->mask = 32;
		end = strchr(optarg, '/');
		if (end != NULL) {
			*end++ = '\0';
			if (!xtables_strtoui(end, NULL, &mask, 0, 32))
				xtables_param_act(XTF_BAD_VALUE, "RAWSNAT",
					"--to-source", optarg);
			info->mask = mask;
		}
		a = xtables_numeric_to_ipaddr(optarg);
		if (a == NULL)
			xtables_param_act(XTF_BAD_VALUE, "RAWSNAT",
				"--to-source", optarg);
		memcpy(&info->addr.in, a, sizeof(*a));
		*flags |= FLAGS_TO;
		return true;
	}
	return false;
}

static int
rawsnat_tg6_parse(int c, char **argv, int invert, unsigned int *flags,
                  const void *entry, struct xt_entry_target **target)
{
	struct xt_rawnat_tginfo *info = (void *)(*target)->data;
	struct in6_addr *a;
	unsigned int mask;
	char *end;

	switch (c) {
	case 't':
		info->mask = 128;
		end = strchr(optarg, '/');
		if (end != NULL) {
			*end++ = '\0';
			if (!xtables_strtoui(end, NULL, &mask, 0, 128))
				xtables_param_act(XTF_BAD_VALUE, "RAWSNAT",
					"--to-source", optarg);
			info->mask = mask;
		}
		a = xtables_numeric_to_ip6addr(optarg);
		if (a == NULL)
			xtables_param_act(XTF_BAD_VALUE, "RAWSNAT",
				"--to-source", optarg);
		memcpy(&info->addr.in6, a, sizeof(*a));
		*flags |= FLAGS_TO;
		return true;
	}
	return false;
}

static void rawsnat_tg_check(unsigned int flags)
{
	if (!(flags & FLAGS_TO))
		xtables_error(PARAMETER_PROBLEM, "RAWSNAT: "
			"\"--to-source\" is required.");
}

static void
rawsnat_tg4_print(const void *entry, const struct xt_entry_target *target,
                  int numeric)
{
	const struct xt_rawnat_tginfo *info = (const void *)target->data;

	if (!numeric && info->mask == 32)
		printf("to-source %s ",
		       xtables_ipaddr_to_anyname(&info->addr.in));
	else
		printf("to-source %s/%u ",
		       xtables_ipaddr_to_numeric(&info->addr.in), info->mask);
}

static void
rawsnat_tg6_print(const void *entry, const struct xt_entry_target *target,
                  int numeric)
{
	const struct xt_rawnat_tginfo *info = (const void *)target->data;

	if (!numeric && info->mask == 128)
		printf("to-source %s ",
		       xtables_ip6addr_to_anyname(&info->addr.in6));
	else
		printf("to-source %s/%u ",
		       xtables_ip6addr_to_numeric(&info->addr.in6), info->mask);
}

static void
rawsnat_tg4_save(const void *entry, const struct xt_entry_target *target)
{
	const struct xt_rawnat_tginfo *info = (const void *)target->data;

	printf("--to-source %s/%u ",
	       xtables_ipaddr_to_numeric(&info->addr.in),
	       info->mask);
}

static void
rawsnat_tg6_save(const void *entry, const struct xt_entry_target *target)
{
	const struct xt_rawnat_tginfo *info = (const void *)target->data;

	printf("--to-source %s/%u ",
	       xtables_ip6addr_to_numeric(&info->addr.in6),
	       info->mask);
}

static struct xtables_target rawsnat_tg4_reg = {
	.version       = XTABLES_VERSION,
	.name          = "RAWSNAT",
	.revision      = 0,
	.family        = NFPROTO_IPV4,
	.size          = XT_ALIGN(sizeof(struct xt_rawnat_tginfo)),
	.userspacesize = XT_ALIGN(sizeof(struct xt_rawnat_tginfo)),
	.help          = rawsnat_tg_help,
	.parse         = rawsnat_tg4_parse,
	.final_check   = rawsnat_tg_check,
	.print         = rawsnat_tg4_print,
	.save          = rawsnat_tg4_save,
	.extra_opts    = rawsnat_tg_opts,
};

static struct xtables_target rawsnat_tg6_reg = {
	.version       = XTABLES_VERSION,
	.name          = "RAWSNAT",
	.revision      = 0,
	.family        = NFPROTO_IPV6,
	.size          = XT_ALIGN(sizeof(struct xt_rawnat_tginfo)),
	.userspacesize = XT_ALIGN(sizeof(struct xt_rawnat_tginfo)),
	.help          = rawsnat_tg_help,
	.parse         = rawsnat_tg6_parse,
	.final_check   = rawsnat_tg_check,
	.print         = rawsnat_tg6_print,
	.save          = rawsnat_tg6_save,
	.extra_opts    = rawsnat_tg_opts,
};

static void _init(void)
{
	xtables_register_target(&rawsnat_tg4_reg);
	xtables_register_target(&rawsnat_tg6_reg);
}