#include <stdio.h>

#include <xtables.h>

#include <linux/netfilter_ipv6/ip6t_frag.h>

enum {

	O_FRAGID = 0,

	O_FRAGLEN,

	O_FRAGRES,

	O_FRAGFIRST,

	O_FRAGMORE,

	O_FRAGLAST,

	F_FRAGMORE = 1 << O_FRAGMORE,

	F_FRAGLAST = 1 << O_FRAGLAST,

};

static void frag_help(void)

{

	printf(

"frag match options:\n"

"[!] --fragid id[:id]           match the id (range)\n"

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

" --fragres                     check the reserved field too\n"

" --fragfirst                   matches on the first fragment\n"

" [--fragmore|--fraglast]       there are more fragments or this\n"

"                               is the last one\n");

}

#define s struct ip6t_frag

static const struct xt_option_entry frag_opts[] = {

	{.name = "fragid", .id = O_FRAGID, .type = XTTYPE_UINT32RC,

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

	{.name = "fraglen", .id = O_FRAGLEN, .type = XTTYPE_UINT32,

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

	{.name = "fragres", .id = O_FRAGRES, .type = XTTYPE_NONE},

	{.name = "fragfirst", .id = O_FRAGFIRST, .type = XTTYPE_NONE},

	{.name = "fragmore", .id = O_FRAGMORE, .type = XTTYPE_NONE,

	 .excl = F_FRAGLAST},

	{.name = "fraglast", .id = O_FRAGLAST, .type = XTTYPE_NONE,

	 .excl = F_FRAGMORE},

	XTOPT_TABLEEND,

};

#undef s

static void frag_init(struct xt_entry_match *m)

{

	struct ip6t_frag *fraginfo = (void *)m->data;

	fraginfo->ids[1] = ~0U;

}

static void frag_parse(struct xt_option_call *cb)

{

	struct ip6t_frag *fraginfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_FRAGID:

		if (cb->nvals == 1)

			fraginfo->ids[1] = fraginfo->ids[0];

		if (cb->invert)

			fraginfo->invflags |= IP6T_FRAG_INV_IDS;

		/*

		 * Note however that IP6T_FRAG_IDS is not tested by anything,

		 * so it is merely here for completeness.

		 */

		fraginfo->flags |= IP6T_FRAG_IDS;

		break;

	case O_FRAGLEN:

		/*

		 * As of Linux 3.0, the kernel does not check for

		 * fraglen at all.

		 */

		if (cb->invert)

			fraginfo->invflags |= IP6T_FRAG_INV_LEN;

		fraginfo->flags |= IP6T_FRAG_LEN;

		break;

	case O_FRAGRES:

		fraginfo->flags |= IP6T_FRAG_RES;

		break;

	case O_FRAGFIRST:

		fraginfo->flags |= IP6T_FRAG_FST;

		break;

	case O_FRAGMORE:

		fraginfo->flags |= IP6T_FRAG_MF;

		break;

	case O_FRAGLAST:

		fraginfo->flags |= IP6T_FRAG_NMF;

		break;

	}

}

static void

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

	    int invert)

{

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

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

		printf("%s", name);

		if (min == max)

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

		else

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

	}

}

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

                       int numeric)

{

	const struct ip6t_frag *frag = (struct ip6t_frag *)match->data;

	printf(" frag ");

	print_ids("id", frag->ids[0], frag->ids[1],

		    frag->invflags & IP6T_FRAG_INV_IDS);

	if (frag->flags & IP6T_FRAG_LEN) {

		printf(" length:%s%u",

			frag->invflags & IP6T_FRAG_INV_LEN ? "!" : "",

			frag->hdrlen);

	}

	if (frag->flags & IP6T_FRAG_RES)

		printf(" reserved");

	if (frag->flags & IP6T_FRAG_FST)

		printf(" first");

	if (frag->flags & IP6T_FRAG_MF)

		printf(" more");

	if (frag->flags & IP6T_FRAG_NMF)

		printf(" last");

	if (frag->invflags & ~IP6T_FRAG_INV_MASK)

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

		       frag->invflags & ~IP6T_FRAG_INV_MASK);

}

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

{

	const struct ip6t_frag *fraginfo = (struct ip6t_frag *)match->data;

	if (!(fraginfo->ids[0] == 0

	    && fraginfo->ids[1] == 0xFFFFFFFF)) {

		printf("%s --fragid ",

			(fraginfo->invflags & IP6T_FRAG_INV_IDS) ? " !" : "");

		if (fraginfo->ids[0]

		    != fraginfo->ids[1])

			printf("%u:%u",

			       fraginfo->ids[0],

			       fraginfo->ids[1]);

		else

			printf("%u",

			       fraginfo->ids[0]);

	}

	if (fraginfo->flags & IP6T_FRAG_LEN) {

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

			(fraginfo->invflags & IP6T_FRAG_INV_LEN) ? " !" : "",

			fraginfo->hdrlen);

	}

	if (fraginfo->flags & IP6T_FRAG_RES)

		printf(" --fragres");

	if (fraginfo->flags & IP6T_FRAG_FST)

		printf(" --fragfirst");

	if (fraginfo->flags & IP6T_FRAG_MF)

		printf(" --fragmore");

	if (fraginfo->flags & IP6T_FRAG_NMF)

		printf(" --fraglast");

}

static int frag_xlate(struct xt_xlate *xl,

		      const struct xt_xlate_mt_params *params)

{

	const struct ip6t_frag *fraginfo =

		(struct ip6t_frag *)params->match->data;

	char *space= "";

	if (!(fraginfo->ids[0] == 0 && fraginfo->ids[1] == 0xFFFFFFFF)) {

		xt_xlate_add(xl, "frag id %s",

			     (fraginfo->invflags & IP6T_FRAG_INV_IDS) ?

			     "!= " : "");

		if (fraginfo->ids[0] != fraginfo->ids[1])

			xt_xlate_add(xl, "%u-%u", fraginfo->ids[0],

				     fraginfo->ids[1]);

		else

			xt_xlate_add(xl, "%u", fraginfo->ids[0]);

		space = " ";

	}

	if (fraginfo->flags & IP6T_FRAG_RES) {

		xt_xlate_add(xl, "%sfrag reserved 1", space);

		space = " ";

	}

	if (fraginfo->flags & IP6T_FRAG_FST) {

		xt_xlate_add(xl, "%sfrag frag-off 0", space);

		space = " ";

	}

	if (fraginfo->flags & IP6T_FRAG_MF) {

		xt_xlate_add(xl, "%sfrag more-fragments 1", space);

		space = " ";

	}

	if (fraginfo->flags & IP6T_FRAG_NMF) {

		xt_xlate_add(xl, "%sfrag more-fragments 0", space);

	}

	return 1;

}

static struct xtables_match frag_mt6_reg = {

	.name          = "frag",

	.version       = XTABLES_VERSION,

	.family        = NFPROTO_IPV6,

	.size          = XT_ALIGN(sizeof(struct ip6t_frag)),

	.userspacesize = XT_ALIGN(sizeof(struct ip6t_frag)),

	.help          = frag_help,

	.init          = frag_init,

	.print         = frag_print,

	.save          = frag_save,

	.x6_parse      = frag_parse,

	.x6_options    = frag_opts,

	.xlate	       = frag_xlate,

};

void

_init(void)

{

	xtables_register_match(&frag_mt6_reg);

}