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/* Shared library add-on to ip6tables to add AH support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <errno.h>
#include <ip6tables.h>
#include <linux/netfilter_ipv6/ip6t_ah.h>
static void ah_help(void)
{
printf(
"ah match options:\n"
"[!] --ahspi spi[:spi] match spi (range)\n"
"[!] --ahlen length total length of this header\n"
" --ahres check the reserved filed, too\n");
}
static const struct option ah_opts[] = {
{ .name = "ahspi", .has_arg = 1, .val = '1' },
{ .name = "ahlen", .has_arg = 1, .val = '2' },
{ .name = "ahres", .has_arg = 0, .val = '3' },
{ .name = NULL }
};
static u_int32_t
parse_ah_spi(const char *spistr, const char *typestr)
{
unsigned long int spi;
char* ep;
spi = strtoul(spistr, &ep, 0);
if ( spistr == ep )
exit_error(PARAMETER_PROBLEM,
"AH no valid digits in %s `%s'", typestr, spistr);
if ( spi == ULONG_MAX && errno == ERANGE )
exit_error(PARAMETER_PROBLEM,
"%s `%s' specified too big: would overflow",
typestr, spistr);
if ( *spistr != '\0' && *ep != '\0' )
exit_error(PARAMETER_PROBLEM,
"AH error parsing %s `%s'", typestr, spistr);
return (u_int32_t) spi;
}
static void
parse_ah_spis(const char *spistring, u_int32_t *spis)
{
char *buffer;
char *cp;
buffer = strdup(spistring);
if ((cp = strchr(buffer, ':')) == NULL)
spis[0] = spis[1] = parse_ah_spi(buffer, "spi");
else {
*cp = '\0';
cp++;
spis[0] = buffer[0] ? parse_ah_spi(buffer, "spi") : 0;
spis[1] = cp[0] ? parse_ah_spi(cp, "spi") : 0xFFFFFFFF;
}
free(buffer);
}
static void ah_init(struct xt_entry_match *m)
{
struct ip6t_ah *ahinfo = (struct ip6t_ah *)m->data;
ahinfo->spis[1] = 0xFFFFFFFF;
ahinfo->hdrlen = 0;
ahinfo->hdrres = 0;
}
static int ah_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct ip6t_ah *ahinfo = (struct ip6t_ah *)(*match)->data;
switch (c) {
case '1':
if (*flags & IP6T_AH_SPI)
exit_error(PARAMETER_PROBLEM,
"Only one `--ahspi' allowed");
check_inverse(optarg, &invert, &optind, 0);
parse_ah_spis(argv[optind-1], ahinfo->spis);
if (invert)
ahinfo->invflags |= IP6T_AH_INV_SPI;
*flags |= IP6T_AH_SPI;
break;
case '2':
if (*flags & IP6T_AH_LEN)
exit_error(PARAMETER_PROBLEM,
"Only one `--ahlen' allowed");
check_inverse(optarg, &invert, &optind, 0);
ahinfo->hdrlen = parse_ah_spi(argv[optind-1], "length");
if (invert)
ahinfo->invflags |= IP6T_AH_INV_LEN;
*flags |= IP6T_AH_LEN;
break;
case '3':
if (*flags & IP6T_AH_RES)
exit_error(PARAMETER_PROBLEM,
"Only one `--ahres' allowed");
ahinfo->hdrres = 1;
*flags |= IP6T_AH_RES;
break;
default:
return 0;
}
return 1;
}
static void
print_spis(const char *name, u_int32_t min, u_int32_t max,
int invert)
{
const char *inv = invert ? "!" : "";
if (min != 0 || max != 0xFFFFFFFF || invert) {
if (min == max)
printf("%s:%s%u ", name, inv, min);
else
printf("%ss:%s%u:%u ", name, inv, min, max);
}
}
static void
print_len(const char *name, u_int32_t len, int invert)
{
const char *inv = invert ? "!" : "";
if (len != 0 || invert)
printf("%s:%s%u ", name, inv, len);
}
static void ah_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ip6t_ah *ah = (struct ip6t_ah *)match->data;
printf("ah ");
print_spis("spi", ah->spis[0], ah->spis[1],
ah->invflags & IP6T_AH_INV_SPI);
print_len("length", ah->hdrlen,
ah->invflags & IP6T_AH_INV_LEN);
if (ah->hdrres)
printf("reserved ");
if (ah->invflags & ~IP6T_AH_INV_MASK)
printf("Unknown invflags: 0x%X ",
ah->invflags & ~IP6T_AH_INV_MASK);
}
static void ah_save(const void *ip, const struct xt_entry_match *match)
{
const struct ip6t_ah *ahinfo = (struct ip6t_ah *)match->data;
if (!(ahinfo->spis[0] == 0
&& ahinfo->spis[1] == 0xFFFFFFFF)) {
printf("--ahspi %s",
(ahinfo->invflags & IP6T_AH_INV_SPI) ? "! " : "");
if (ahinfo->spis[0]
!= ahinfo->spis[1])
printf("%u:%u ",
ahinfo->spis[0],
ahinfo->spis[1]);
else
printf("%u ",
ahinfo->spis[0]);
}
if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN) ) {
printf("--ahlen %s%u ",
(ahinfo->invflags & IP6T_AH_INV_LEN) ? "! " : "",
ahinfo->hdrlen);
}
if (ahinfo->hdrres != 0 )
printf("--ahres ");
}
static struct xtables_match ah_mt6_reg = {
.name = "ah",
.version = XTABLES_VERSION,
.family = PF_INET6,
.size = XT_ALIGN(sizeof(struct ip6t_ah)),
.userspacesize = XT_ALIGN(sizeof(struct ip6t_ah)),
.help = ah_help,
.init = ah_init,
.parse = ah_parse,
.print = ah_print,
.save = ah_save,
.extra_opts = ah_opts,
};
void
_init(void)
{
xtables_register_match(&ah_mt6_reg);
}
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