#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <errno.h>

#include <xtables.h>

#include <linux/netfilter_ipv6/ip6t_opts.h>

enum {

	O_DSTLEN = 0,

	O_DSTOPTS,

};

static void dst_help(void)

{

	printf(

"dst match options:\n"

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

"  --dst-opts TYPE[:LEN][,TYPE[:LEN]...]\n"

"                                Options and its length (list, max: %d)\n",

IP6T_OPTS_OPTSNR);

}

static const struct xt_option_entry dst_opts[] = {

	{.name = "dst-len", .id = O_DSTLEN, .type = XTTYPE_UINT32,

	 .flags = XTOPT_INVERT | XTOPT_PUT,

	 XTOPT_POINTER(struct ip6t_opts, hdrlen)},

	{.name = "dst-opts", .id = O_DSTOPTS, .type = XTTYPE_STRING},

	XTOPT_TABLEEND,

};

static uint32_t

parse_opts_num(const char *idstr, const char *typestr)

{

	unsigned long int id;

	char* ep;

	id = strtoul(idstr, &ep, 0);

	if ( idstr == ep ) {

		xtables_error(PARAMETER_PROBLEM,

		           "dst: no valid digits in %s `%s'", typestr, idstr);

	}

	if ( id == ULONG_MAX  && errno == ERANGE ) {

		xtables_error(PARAMETER_PROBLEM,

			   "%s `%s' specified too big: would overflow",

			   typestr, idstr);

	}

	if ( *idstr != '\0'  && *ep != '\0' ) {

		xtables_error(PARAMETER_PROBLEM,

		           "dst: error parsing %s `%s'", typestr, idstr);

	}

	return id;

}

static int

parse_options(const char *optsstr, uint16_t *opts)

{

        char *buffer, *cp, *next, *range;

        unsigned int i;

	buffer = strdup(optsstr);

        if (!buffer)

		xtables_error(OTHER_PROBLEM, "strdup failed");

        for (cp = buffer, i = 0; cp && i < IP6T_OPTS_OPTSNR; cp = next, i++)

        {

                next = strchr(cp, ',');

                if (next)

			*next++='\0';

                range = strchr(cp, ':');

                if (range) {

                        if (i == IP6T_OPTS_OPTSNR-1)

				xtables_error(PARAMETER_PROBLEM,

                                           "too many ports specified");

                        *range++ = '\0';

                }

		opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;

                if (range) {

			if (opts[i] == 0)

				xtables_error(PARAMETER_PROBLEM,

					"PAD0 hasn't got length");

			opts[i] |= parse_opts_num(range, "length") & 0xFF;

                } else

                        opts[i] |= (0x00FF);

#ifdef DEBUG

		printf("opts str: %s %s\n", cp, range);

		printf("opts opt: %04X\n", opts[i]);

#endif

	}

        if (cp)

		xtables_error(PARAMETER_PROBLEM, "too many addresses specified");

	free(buffer);

#ifdef DEBUG

	printf("addr nr: %d\n", i);

#endif

	return i;

}

static void dst_parse(struct xt_option_call *cb)

{

	struct ip6t_opts *optinfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_DSTLEN:

		if (cb->invert)

			optinfo->invflags |= IP6T_OPTS_INV_LEN;

		optinfo->flags |= IP6T_OPTS_LEN;

		break;

	case O_DSTOPTS:

		optinfo->optsnr = parse_options(cb->arg, optinfo->opts);

		optinfo->flags |= IP6T_OPTS_OPTS;

		break;

	}

}

static void

print_options(unsigned int optsnr, uint16_t *optsp)

{

	unsigned int i;

	printf(" ");

	for(i = 0; i < optsnr; i++) {

		printf("%d", (optsp[i] & 0xFF00) >> 8);

		if ((optsp[i] & 0x00FF) != 0x00FF)

			printf(":%d", (optsp[i] & 0x00FF));

		printf("%c", (i != optsnr - 1) ? ',' : ' ');

	}

}

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

                      int numeric)

{

	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;

	printf(" dst");

	if (optinfo->flags & IP6T_OPTS_LEN)

		printf(" length:%s%u",

			optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "",

			optinfo->hdrlen);

	if (optinfo->flags & IP6T_OPTS_OPTS)

		printf(" opts");

	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);

	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)

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

		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);

}

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

{

	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;

	if (optinfo->flags & IP6T_OPTS_LEN) {

		printf("%s --dst-len %u",

			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",

			optinfo->hdrlen);

	}

	if (optinfo->flags & IP6T_OPTS_OPTS)

		printf(" --dst-opts");

	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);

}

static struct xtables_match dst_mt6_reg = {

	.name          = "dst",

	.version       = XTABLES_VERSION,

	.family        = NFPROTO_IPV6,

	.size          = XT_ALIGN(sizeof(struct ip6t_opts)),

	.userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),

	.help          = dst_help,

	.print         = dst_print,

	.save          = dst_save,

	.x6_parse      = dst_parse,

	.x6_options    = dst_opts,

};

void

_init(void)

{

	xtables_register_match(&dst_mt6_reg);

}