#include <stdio.h>

#include <xtables.h>

#include <linux/netfilter_ipv6/ip6t_ah.h>

enum {

	O_AHSPI = 0,

	O_AHLEN,

	O_AHRES,

};

static void ah_help(void)

{

	printf(

"ah match options:\n"

"[!] --ahspi spi[:spi]          match spi (range)\n"

"[!] --ahlen length             total length of this header\n"

" --ahres                       check the reserved field too\n");

}

#define s struct ip6t_ah

static const struct xt_option_entry ah_opts[] = {

	{.name = "ahspi", .id = O_AHSPI, .type = XTTYPE_UINT32RC,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spis)},

	{.name = "ahlen", .id = O_AHLEN, .type = XTTYPE_UINT32,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hdrlen)},

	{.name = "ahres", .id = O_AHRES, .type = XTTYPE_NONE},

	XTOPT_TABLEEND,

};

#undef s

static void ah_init(struct xt_entry_match *m)

{

	struct ip6t_ah *ahinfo = (void *)m->data;

	/* Defaults for when no --ahspi is used at all */

	ahinfo->spis[1] = ~0U;

}

static void ah_parse(struct xt_option_call *cb)

{

	struct ip6t_ah *ahinfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_AHSPI:

		if (cb->nvals == 1)

			ahinfo->spis[1] = ahinfo->spis[0];

		if (cb->invert)

			ahinfo->invflags |= IP6T_AH_INV_SPI;

		break;

	case O_AHLEN:

		if (cb->invert)

			ahinfo->invflags |= IP6T_AH_INV_LEN;

		break;

	case O_AHRES:

		ahinfo->hdrres = 1;

		break;

	}

}

static void

print_spis(const char *name, uint32_t min, uint32_t max,

	    int invert)

{

	const char *inv = invert ? "!" : "";

	if (min != 0 || max != 0xFFFFFFFF || invert) {

		if (min == max)

			printf("%s:%s%u", name, inv, min);

		else

			printf("%ss:%s%u:%u", name, inv, min, max);

	}

}

static void

print_len(const char *name, uint32_t len, int invert)

{

	const char *inv = invert ? "!" : "";

	if (len != 0 || invert)

		printf("%s:%s%u", name, inv, len);

}

static void ah_print(const void *ip, const struct xt_entry_match *match,

                     int numeric)

{

	const struct ip6t_ah *ah = (struct ip6t_ah *)match->data;

	printf(" ah ");

	print_spis("spi", ah->spis[0], ah->spis[1],

		    ah->invflags & IP6T_AH_INV_SPI);

	print_len("length", ah->hdrlen, 

		    ah->invflags & IP6T_AH_INV_LEN);

	if (ah->hdrres)

		printf(" reserved");

	if (ah->invflags & ~IP6T_AH_INV_MASK)

		printf(" Unknown invflags: 0x%X",

		       ah->invflags & ~IP6T_AH_INV_MASK);

}

static void ah_save(const void *ip, const struct xt_entry_match *match)

{

	const struct ip6t_ah *ahinfo = (struct ip6t_ah *)match->data;

	if (!(ahinfo->spis[0] == 0

	    && ahinfo->spis[1] == 0xFFFFFFFF)) {

		printf("%s --ahspi ",

			(ahinfo->invflags & IP6T_AH_INV_SPI) ? " !" : "");

		if (ahinfo->spis[0]

		    != ahinfo->spis[1])

			printf("%u:%u",

			       ahinfo->spis[0],

			       ahinfo->spis[1]);

		else

			printf("%u",

			       ahinfo->spis[0]);

	}

	if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN) ) {

		printf("%s --ahlen %u",

			(ahinfo->invflags & IP6T_AH_INV_LEN) ? " !" : "",

			ahinfo->hdrlen);

	}

	if (ahinfo->hdrres != 0 )

		printf(" --ahres");

}

static int ah_xlate(struct xt_xlate *xl,

		    const struct xt_xlate_mt_params *params)

{

	const struct ip6t_ah *ahinfo = (struct ip6t_ah *)params->match->data;

	char *space = "";

	if (!(ahinfo->spis[0] == 0 && ahinfo->spis[1] == 0xFFFFFFFF)) {

		xt_xlate_add(xl, "ah spi%s ",

			(ahinfo->invflags & IP6T_AH_INV_SPI) ? " !=" : "");

		if (ahinfo->spis[0] != ahinfo->spis[1])

			xt_xlate_add(xl, "%u-%u", ahinfo->spis[0],

				     ahinfo->spis[1]);

		else

			xt_xlate_add(xl, "%u", ahinfo->spis[0]);

		space = " ";

	}

	if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN)) {

		xt_xlate_add(xl, "%sah hdrlength%s %u", space,

			     (ahinfo->invflags & IP6T_AH_INV_LEN) ? " !=" : "",

			     ahinfo->hdrlen);

		space = " ";

	}

	if (ahinfo->hdrres != 0) {

		xt_xlate_add(xl, "%sah reserved %u", space, ahinfo->hdrres);

		space = " ";

	}

	if (!space[0]) /* plain '-m ah' */

		xt_xlate_add(xl, "meta l4proto ah");

	return 1;

}

static struct xtables_match ah_mt6_reg = {

	.name          = "ah",

	.version       = XTABLES_VERSION,

	.family        = NFPROTO_IPV6,

	.size          = XT_ALIGN(sizeof(struct ip6t_ah)),

	.userspacesize = XT_ALIGN(sizeof(struct ip6t_ah)),

	.help          = ah_help,

	.init          = ah_init,

	.print         = ah_print,

	.save          = ah_save,

	.x6_parse      = ah_parse,

	.x6_options    = ah_opts,

	.xlate	       = ah_xlate,

};

void

_init(void)

{

	xtables_register_match(&ah_mt6_reg);

}