You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
91 lines
2.1 KiB
91 lines
2.1 KiB
#include <stdio.h> |
|
#include <xtables.h> |
|
#include <linux/netfilter/xt_length.h> |
|
|
|
enum { |
|
O_LENGTH = 0, |
|
}; |
|
|
|
static void length_help(void) |
|
{ |
|
printf( |
|
"length match options:\n" |
|
"[!] --length length[:length] Match packet length against value or range\n" |
|
" of values (inclusive)\n"); |
|
} |
|
|
|
static const struct xt_option_entry length_opts[] = { |
|
{.name = "length", .id = O_LENGTH, .type = XTTYPE_UINT16RC, |
|
.flags = XTOPT_MAND | XTOPT_INVERT}, |
|
XTOPT_TABLEEND, |
|
}; |
|
|
|
static void length_parse(struct xt_option_call *cb) |
|
{ |
|
struct xt_length_info *info = cb->data; |
|
|
|
xtables_option_parse(cb); |
|
info->min = cb->val.u16_range[0]; |
|
info->max = cb->val.u16_range[0]; |
|
if (cb->nvals >= 2) |
|
info->max = cb->val.u16_range[1]; |
|
if (cb->invert) |
|
info->invert = 1; |
|
} |
|
|
|
static void |
|
length_print(const void *ip, const struct xt_entry_match *match, int numeric) |
|
{ |
|
const struct xt_length_info *info = (void *)match->data; |
|
|
|
printf(" length %s", info->invert ? "!" : ""); |
|
if (info->min == info->max) |
|
printf("%u", info->min); |
|
else |
|
printf("%u:%u", info->min, info->max); |
|
} |
|
|
|
static void length_save(const void *ip, const struct xt_entry_match *match) |
|
{ |
|
const struct xt_length_info *info = (void *)match->data; |
|
|
|
printf("%s --length ", info->invert ? " !" : ""); |
|
if (info->min == info->max) |
|
printf("%u", info->min); |
|
else |
|
printf("%u:%u", info->min, info->max); |
|
} |
|
|
|
static int length_xlate(struct xt_xlate *xl, |
|
const struct xt_xlate_mt_params *params) |
|
{ |
|
const struct xt_length_info *info = (void *)params->match->data; |
|
|
|
xt_xlate_add(xl, "meta length %s", info->invert ? "!= " : ""); |
|
if (info->min == info->max) |
|
xt_xlate_add(xl, "%u", info->min); |
|
else |
|
xt_xlate_add(xl, "%u-%u", info->min, info->max); |
|
|
|
return 1; |
|
} |
|
|
|
|
|
static struct xtables_match length_match = { |
|
.family = NFPROTO_UNSPEC, |
|
.name = "length", |
|
.version = XTABLES_VERSION, |
|
.size = XT_ALIGN(sizeof(struct xt_length_info)), |
|
.userspacesize = XT_ALIGN(sizeof(struct xt_length_info)), |
|
.help = length_help, |
|
.print = length_print, |
|
.save = length_save, |
|
.x6_parse = length_parse, |
|
.x6_options = length_opts, |
|
.xlate = length_xlate, |
|
}; |
|
|
|
void _init(void) |
|
{ |
|
xtables_register_match(&length_match); |
|
}
|
|
|