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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6t_opts.h>
#define DEBUG 0
enum {
O_HBH_LEN = 0,
O_HBH_OPTS,
};
static void hbh_help(void)
{
printf(
"hbh match options:\n"
"[!] --hbh-len length total length of this header\n"
" --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
" Options and its length (list, max: %d)\n",
IP6T_OPTS_OPTSNR);
}
static const struct xt_option_entry hbh_opts[] = {
{.name = "hbh-len", .id = O_HBH_LEN, .type = XTTYPE_UINT32,
.flags = XTOPT_INVERT | XTOPT_PUT,
XTOPT_POINTER(struct ip6t_opts, hdrlen)},
{.name = "hbh-opts", .id = O_HBH_OPTS, .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,
"hbh: 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,
"hbh: 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 has not got length");
opts[i] |= parse_opts_num(range, "length") & 0xFF;
} else {
opts[i] |= (0x00FF);
}
#if 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);
#if DEBUG
printf("addr nr: %d\n", i);
#endif
return i;
}
static void hbh_parse(struct xt_option_call *cb)
{
struct ip6t_opts *optinfo = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_HBH_LEN:
if (cb->invert)
optinfo->invflags |= IP6T_OPTS_INV_LEN;
optinfo->flags |= IP6T_OPTS_LEN;
break;
case O_HBH_OPTS:
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;
for(i=0; i<optsnr; i++){
printf("%c", (i==0)?' ':',');
printf("%d", (optsp[i] & 0xFF00)>>8);
if ((optsp[i] & 0x00FF) != 0x00FF){
printf(":%d", (optsp[i] & 0x00FF));
}
}
}
static void hbh_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
printf(" hbh");
if (optinfo->flags & IP6T_OPTS_LEN) {
printf(" length");
printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
printf("%u", 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 hbh_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 --hbh-len %u",
(optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",
optinfo->hdrlen);
}
if (optinfo->flags & IP6T_OPTS_OPTS)
printf(" --hbh-opts");
print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
}
static int hbh_xlate(const void *ip, const struct xt_entry_match *match,
struct xt_xlate *xl, int numeric)
{
const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
if (!(optinfo->flags & IP6T_OPTS_LEN) ||
(optinfo->flags & IP6T_OPTS_OPTS))
return 0;
xt_xlate_add(xl, "hbh hdrlength %s%u ",
(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "!= " : "",
optinfo->hdrlen);
return 1;
}
static struct xtables_match hbh_mt6_reg = {
.name = "hbh",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV6,
.size = XT_ALIGN(sizeof(struct ip6t_opts)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),
.help = hbh_help,
.print = hbh_print,
.save = hbh_save,
.x6_parse = hbh_parse,
.x6_options = hbh_opts,
.xlate = hbh_xlate,
};
void
_init(void)
{
xtables_register_match(&hbh_mt6_reg);
}
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