text: #include <getopt.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <xtables.h>
  #include <linux/netfilter/xt_MARK.h>
  
  /* Version 0 */
  struct xt_mark_target_info {
  	unsigned long mark;
  };
  
  /* Version 1 */
  enum {
  	XT_MARK_SET=0,
  	XT_MARK_AND,
  	XT_MARK_OR,
  };
  
  struct xt_mark_target_info_v1 {
  	unsigned long mark;
  	uint8_t mode;
  };
  
  enum {
  	O_SET_MARK = 0,
  	O_AND_MARK,
  	O_OR_MARK,
  	O_XOR_MARK,
  	O_SET_XMARK,
  	F_SET_MARK  = 1 << O_SET_MARK,
  	F_AND_MARK  = 1 << O_AND_MARK,
  	F_OR_MARK   = 1 << O_OR_MARK,
  	F_XOR_MARK  = 1 << O_XOR_MARK,
  	F_SET_XMARK = 1 << O_SET_XMARK,
  	F_ANY       = F_SET_MARK | F_AND_MARK | F_OR_MARK |
  	              F_XOR_MARK | F_SET_XMARK,
  };
  
  static void MARK_help(void)
  {
  	printf(
  "MARK target options:\n"
  "  --set-mark value                   Set nfmark value\n"
  "  --and-mark value                   Binary AND the nfmark with value\n"
  "  --or-mark  value                   Binary OR  the nfmark with value\n");
  }
  
  static const struct xt_option_entry MARK_opts[] = {
  	{.name = "set-mark", .id = O_SET_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	{.name = "and-mark", .id = O_AND_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	{.name = "or-mark", .id = O_OR_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	XTOPT_TABLEEND,
  };
  
  static const struct xt_option_entry mark_tg_opts[] = {
  	{.name = "set-xmark", .id = O_SET_XMARK, .type = XTTYPE_MARKMASK32,
  	 .excl = F_ANY},
  	{.name = "set-mark", .id = O_SET_MARK, .type = XTTYPE_MARKMASK32,
  	 .excl = F_ANY},
  	{.name = "and-mark", .id = O_AND_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	{.name = "or-mark", .id = O_OR_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	{.name = "xor-mark", .id = O_XOR_MARK, .type = XTTYPE_UINT32,
  	 .excl = F_ANY},
  	XTOPT_TABLEEND,
  };
  
  static void mark_tg_help(void)
  {
  	printf(
  "MARK target options:\n"
  "  --set-xmark value[/mask]  Clear bits in mask and XOR value into nfmark\n"
  "  --set-mark value[/mask]   Clear bits in mask and OR value into nfmark\n"
  "  --and-mark bits           Binary AND the nfmark with bits\n"
  "  --or-mark bits            Binary OR the nfmark with bits\n"
  "  --xor-mark bits           Binary XOR the nfmark with bits\n"
  "\n");
  }
  
  static void MARK_parse_v0(struct xt_option_call *cb)
  {
  	struct xt_mark_target_info *markinfo = cb->data;
  
  	xtables_option_parse(cb);
  	switch (cb->entry->id) {
  	case O_SET_MARK:
  		markinfo->mark = cb->val.mark;
  		break;
  	default:
  		xtables_error(PARAMETER_PROBLEM,
  			   "MARK target: kernel too old for --%s",
  			   cb->entry->name);
  	}
  }
  
  static void MARK_check(struct xt_fcheck_call *cb)
  {
  	if (cb->xflags == 0)
  		xtables_error(PARAMETER_PROBLEM,
  		           "MARK target: Parameter --set/and/or-mark"
  			   " is required");
  }
  
  static void MARK_parse_v1(struct xt_option_call *cb)
  {
  	struct xt_mark_target_info_v1 *markinfo = cb->data;
  
  	xtables_option_parse(cb);
  	switch (cb->entry->id) {
  	case O_SET_MARK:
  	        markinfo->mode = XT_MARK_SET;
  		break;
  	case O_AND_MARK:
  	        markinfo->mode = XT_MARK_AND;
  		break;
  	case O_OR_MARK:
  	        markinfo->mode = XT_MARK_OR;
  		break;
  	}
  	markinfo->mark = cb->val.u32;
  }
  
  static void mark_tg_parse(struct xt_option_call *cb)
  {
  	struct xt_mark_tginfo2 *info = cb->data;
  
  	xtables_option_parse(cb);
  	switch (cb->entry->id) {
  	case O_SET_XMARK:
  		info->mark = cb->val.mark;
  		info->mask = cb->val.mask;
  		break;
  	case O_SET_MARK:
  		info->mark = cb->val.mark;
  		info->mask = cb->val.mark | cb->val.mask;
  		break;
  	case O_AND_MARK:
  		info->mark = 0;
  		info->mask = ~cb->val.u32;
  		break;
  	case O_OR_MARK:
  		info->mark = info->mask = cb->val.u32;
  		break;
  	case O_XOR_MARK:
  		info->mark = cb->val.u32;
  		info->mask = 0;
  		break;
  	}
  }
  
  static void mark_tg_check(struct xt_fcheck_call *cb)
  {
  	if (cb->xflags == 0)
  		xtables_error(PARAMETER_PROBLEM, "MARK: One of the --set-xmark, "
  		           "--{and,or,xor,set}-mark options is required");
  }
  
  static void
  print_mark(unsigned long mark)
  {
  	printf(" 0x%lx", mark);
  }
  
  static void MARK_print_v0(const void *ip,
                            const struct xt_entry_target *target, int numeric)
  {
  	const struct xt_mark_target_info *markinfo =
  		(const struct xt_mark_target_info *)target->data;
  	printf(" MARK set");
  	print_mark(markinfo->mark);
  }
  
  static void MARK_save_v0(const void *ip, const struct xt_entry_target *target)
  {
  	const struct xt_mark_target_info *markinfo =
  		(const struct xt_mark_target_info *)target->data;
  
  	printf(" --set-mark");
  	print_mark(markinfo->mark);
  }
  
  static void MARK_print_v1(const void *ip, const struct xt_entry_target *target,
                            int numeric)
  {
  	const struct xt_mark_target_info_v1 *markinfo =
  		(const struct xt_mark_target_info_v1 *)target->data;
  
  	switch (markinfo->mode) {
  	case XT_MARK_SET:
  		printf(" MARK set");
  		break;
  	case XT_MARK_AND:
  		printf(" MARK and");
  		break;
  	case XT_MARK_OR:
  		printf(" MARK or");
  		break;
  	}
  	print_mark(markinfo->mark);
  }
  
  static void mark_tg_print(const void *ip, const struct xt_entry_target *target,
                            int numeric)
  {
  	const struct xt_mark_tginfo2 *info = (const void *)target->data;
  
  	if (info->mark == 0)
  		printf(" MARK and 0x%x", (unsigned int)(uint32_t)~info->mask);
  	else if (info->mark == info->mask)
  		printf(" MARK or 0x%x", info->mark);
  	else if (info->mask == 0)
  		printf(" MARK xor 0x%x", info->mark);
  	else if (info->mask == 0xffffffffU)
  		printf(" MARK set 0x%x", info->mark);
  	else
  		printf(" MARK xset 0x%x/0x%x", info->mark, info->mask);
  }
  
  static void MARK_save_v1(const void *ip, const struct xt_entry_target *target)
  {
  	const struct xt_mark_target_info_v1 *markinfo =
  		(const struct xt_mark_target_info_v1 *)target->data;
  
  	switch (markinfo->mode) {
  	case XT_MARK_SET:
  		printf(" --set-mark");
  		break;
  	case XT_MARK_AND:
  		printf(" --and-mark");
  		break;
  	case XT_MARK_OR:
  		printf(" --or-mark");
  		break;
  	}
  	print_mark(markinfo->mark);
  }
  
  static void mark_tg_save(const void *ip, const struct xt_entry_target *target)
  {
  	const struct xt_mark_tginfo2 *info = (const void *)target->data;
  
  	printf(" --set-xmark 0x%x/0x%x", info->mark, info->mask);
  }
  
  static void mark_tg_arp_save(const void *ip, const struct xt_entry_target *target)
  {
  	const struct xt_mark_tginfo2 *info = (const void *)target->data;
  
  	if (info->mark == 0)
  		printf(" --and-mark %x", (unsigned int)(uint32_t)~info->mask);
  	else if (info->mark == info->mask)
  		printf(" --or-mark %x", info->mark);
  	else
  		printf(" --set-mark %x", info->mark);
  }
  
  static void mark_tg_arp_print(const void *ip,
  			      const struct xt_entry_target *target, int numeric)
  {
  	mark_tg_arp_save(ip, target);
  }
  
  #define MARK_OPT 1
  #define AND_MARK_OPT 2
  #define OR_MARK_OPT 3
  
  static struct option mark_tg_arp_opts[] = {
  	{ .name = "set-mark", .has_arg = required_argument, .flag = 0, .val = MARK_OPT },
  	{ .name = "and-mark", .has_arg = required_argument, .flag = 0, .val = AND_MARK_OPT },
  	{ .name = "or-mark", .has_arg = required_argument, .flag = 0, .val =  OR_MARK_OPT },
  	{ .name = NULL}
  };
  
  static int
  mark_tg_arp_parse(int c, char **argv, int invert, unsigned int *flags,
  		  const void *entry, struct xt_entry_target **target)
  {
  	struct xt_mark_tginfo2 *info =
  		(struct xt_mark_tginfo2 *)(*target)->data;
  	int i;
  
  	switch (c) {
  	case MARK_OPT:
  		if (sscanf(argv[optind-1], "%x", &i) != 1) {
  			xtables_error(PARAMETER_PROBLEM,
  				"Bad mark value `%s'", optarg);
  			return 0;
  		}
  		info->mark = i;
  		if (*flags)
  			xtables_error(PARAMETER_PROBLEM,
  				"MARK: Can't specify --set-mark twice");
  		*flags = 1;
  		break;
  	case AND_MARK_OPT:
  		if (sscanf(argv[optind-1], "%x", &i) != 1) {
  			xtables_error(PARAMETER_PROBLEM,
  				"Bad mark value `%s'", optarg);
  			return 0;
  		}
  		info->mark = 0;
  		info->mask = ~i;
  		if (*flags)
  			xtables_error(PARAMETER_PROBLEM,
  				"MARK: Can't specify --and-mark twice");
  		*flags = 1;
  		break;
  	case OR_MARK_OPT:
  		if (sscanf(argv[optind-1], "%x", &i) != 1) {
  			xtables_error(PARAMETER_PROBLEM,
  				"Bad mark value `%s'", optarg);
  			return 0;
  		}
  		info->mark = info->mask = i;
  		if (*flags)
  			xtables_error(PARAMETER_PROBLEM,
  				"MARK: Can't specify --or-mark twice");
  		*flags = 1;
  		break;
  	default:
  		return 0;
  	}
  	return 1;
  }
  
  static int mark_tg_xlate(struct xt_xlate *xl,
  			 const struct xt_xlate_tg_params *params)
  {
  	const struct xt_mark_tginfo2 *info = (const void *)params->target->data;
  
  	xt_xlate_add(xl, "meta mark set ");
  
  	if (info->mask == 0xffffffffU)
  		xt_xlate_add(xl, "0x%x ", info->mark);
  	else if (info->mark == 0)
  		xt_xlate_add(xl, "mark and 0x%x ", ~info->mask);
  	else if (info->mark == info->mask)
  		xt_xlate_add(xl, "mark or 0x%x ", info->mark);
  	else if (info->mask == 0)
  		xt_xlate_add(xl, "mark xor 0x%x ", info->mark);
  	else
  		xt_xlate_add(xl, "mark and 0x%x xor 0x%x ", ~info->mask,
  			     info->mark);
  
  	return 1;
  }
  
  static int MARK_xlate(struct xt_xlate *xl,
  		      const struct xt_xlate_tg_params *params)
  {
  	const struct xt_mark_target_info_v1 *markinfo =
  		(const struct xt_mark_target_info_v1 *)params->target->data;
  
  	xt_xlate_add(xl, "meta mark set ");
  
  	switch(markinfo->mode) {
  	case XT_MARK_SET:
  		xt_xlate_add(xl, "0x%x ", (uint32_t)markinfo->mark);
  		break;
  	case XT_MARK_AND:
  		xt_xlate_add(xl, "mark and 0x%x ", (uint32_t)markinfo->mark);
  		break;
  	case XT_MARK_OR:
  		xt_xlate_add(xl, "mark or 0x%x ", (uint32_t)markinfo->mark);
  		break;
  	}
  
  	return 1;
  }
  
  static struct xtables_target mark_tg_reg[] = {
  	{
  		.family        = NFPROTO_UNSPEC,
  		.name          = "MARK",
  		.version       = XTABLES_VERSION,
  		.revision      = 0,
  		.size          = XT_ALIGN(sizeof(struct xt_mark_target_info)),
  		.userspacesize = XT_ALIGN(sizeof(struct xt_mark_target_info)),
  		.help          = MARK_help,
  		.print         = MARK_print_v0,
  		.save          = MARK_save_v0,
  		.x6_parse      = MARK_parse_v0,
  		.x6_fcheck     = MARK_check,
  		.x6_options    = MARK_opts,
  	},
  	{
  		.family        = NFPROTO_IPV4,
  		.name          = "MARK",
  		.version       = XTABLES_VERSION,
  		.revision      = 1,
  		.size          = XT_ALIGN(sizeof(struct xt_mark_target_info_v1)),
  		.userspacesize = XT_ALIGN(sizeof(struct xt_mark_target_info_v1)),
  		.help          = MARK_help,
  		.print         = MARK_print_v1,
  		.save          = MARK_save_v1,
  		.x6_parse      = MARK_parse_v1,
  		.x6_fcheck     = MARK_check,
  		.x6_options    = MARK_opts,
  		.xlate	       = MARK_xlate,
  	},
  	{
  		.version       = XTABLES_VERSION,
  		.name          = "MARK",
  		.revision      = 2,
  		.family        = NFPROTO_UNSPEC,
  		.size          = XT_ALIGN(sizeof(struct xt_mark_tginfo2)),
  		.userspacesize = XT_ALIGN(sizeof(struct xt_mark_tginfo2)),
  		.help          = mark_tg_help,
  		.print         = mark_tg_print,
  		.save          = mark_tg_save,
  		.x6_parse      = mark_tg_parse,
  		.x6_fcheck     = mark_tg_check,
  		.x6_options    = mark_tg_opts,
  		.xlate	       = mark_tg_xlate,
  	},
  	{
  		.version       = XTABLES_VERSION,
  		.name          = "MARK",
  		.revision      = 2,
  		.family        = NFPROTO_ARP,
  		.size          = XT_ALIGN(sizeof(struct xt_mark_tginfo2)),
  		.userspacesize = XT_ALIGN(sizeof(struct xt_mark_tginfo2)),
  		.help          = mark_tg_help,
  		.print         = mark_tg_arp_print,
  		.save          = mark_tg_arp_save,
  		.parse         = mark_tg_arp_parse,
  		.extra_opts    = mark_tg_arp_opts,
  	},
  };
  
  void _init(void)
  {
  	xtables_register_targets(mark_tg_reg, ARRAY_SIZE(mark_tg_reg));
  }
  