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#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 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,
};
void
_init(void)
{
xtables_register_match(&frag_mt6_reg);
}
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