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/*
* Shared library add-on to iptables to match
* packets by their type (BROADCAST, UNICAST, MULTICAST).
*
* Michal Ludvig <michal@logix.cz>
*/
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#if defined(__GLIBC__) && __GLIBC__ == 2
#include <net/ethernet.h>
#else
#include <linux/if_ether.h>
#endif
#include <xtables.h>
#include <linux/if_packet.h>
#include <linux/netfilter/xt_pkttype.h>
#define PKTTYPE_VERSION "0.1"
struct pkttypes {
const char *name;
unsigned char pkttype;
unsigned char printhelp;
const char *help;
};
static const struct pkttypes supported_types[] = {
{"unicast", PACKET_HOST, 1, "to us"},
{"broadcast", PACKET_BROADCAST, 1, "to all"},
{"multicast", PACKET_MULTICAST, 1, "to group"},
/*
{"otherhost", PACKET_OTHERHOST, 1, "to someone else"},
{"outgoing", PACKET_OUTGOING, 1, "outgoing of any type"},
*/
/* aliases */
{"bcast", PACKET_BROADCAST, 0, NULL},
{"mcast", PACKET_MULTICAST, 0, NULL},
{"host", PACKET_HOST, 0, NULL}
};
static void print_types(void)
{
unsigned int i;
printf("Valid packet types:\n");
for (i = 0; i < ARRAY_SIZE(supported_types); ++i)
if(supported_types[i].printhelp == 1)
printf("\t%-14s\t\t%s\n", supported_types[i].name, supported_types[i].help);
printf("\n");
}
static void pkttype_help(void)
{
printf(
"pkttype match options:\n"
"[!] --pkt-type packettype match packet type\n");
print_types();
}
static const struct option pkttype_opts[] = {
{"pkt-type", 1, NULL, '1'},
{ .name = NULL }
};
static void parse_pkttype(const char *pkttype, struct xt_pkttype_info *info)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(supported_types); ++i)
if(strcasecmp(pkttype, supported_types[i].name)==0)
{
info->pkttype=supported_types[i].pkttype;
return;
}
xtables_error(PARAMETER_PROBLEM, "Bad packet type '%s'", pkttype);
}
static int pkttype_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct xt_pkttype_info *info = (struct xt_pkttype_info *)(*match)->data;
switch(c)
{
case '1':
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
parse_pkttype(optarg, info);
if(invert)
info->invert=1;
*flags=1;
break;
default:
return 0;
}
return 1;
}
static void pkttype_check(unsigned int flags)
{
if (!flags)
xtables_error(PARAMETER_PROBLEM, "You must specify \"--pkt-type\"");
}
static void print_pkttype(const struct xt_pkttype_info *info)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(supported_types); ++i)
if(supported_types[i].pkttype==info->pkttype)
{
printf("%s ", supported_types[i].name);
return;
}
printf("%d ", info->pkttype); /* in case we didn't find an entry in named-packtes */
}
static void pkttype_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct xt_pkttype_info *info = (const void *)match->data;
printf("PKTTYPE %s= ", info->invert?"!":"");
print_pkttype(info);
}
static void pkttype_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_pkttype_info *info = (const void *)match->data;
printf("%s--pkt-type ", info->invert ? "! " : "");
print_pkttype(info);
}
static struct xtables_match pkttype_match = {
.family = NFPROTO_UNSPEC,
.name = "pkttype",
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_pkttype_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_pkttype_info)),
.help = pkttype_help,
.parse = pkttype_parse,
.final_check = pkttype_check,
.print = pkttype_print,
.save = pkttype_save,
.extra_opts = pkttype_opts,
};
void _init(void)
{
xtables_register_match(&pkttype_match);
}
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