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/* ebt_arp
*
* Authors:
* Bart De Schuymer <bdschuym@pandora.be>
* Tim Gardner <timg@tpi.com>
*
* April, 2002
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <xtables.h>
#include <netinet/ether.h>
#include <xtables.h>
#include <net/if_arp.h>
#include <linux/netfilter_bridge/ebt_arp.h>
#include "iptables/nft.h"
#include "iptables/nft-bridge.h"
/* values must correspond with EBT_ARP_* bit positions */
enum {
O_OPCODE = 0,
O_HTYPE,
O_PTYPE,
O_SRC_IP,
O_DST_IP,
O_SRC_MAC,
O_DST_MAC,
O_GRAT,
};
static const struct xt_option_entry brarp_opts[] = {
#define ENTRY(n, i, t) { .name = n, .id = i, .type = t, .flags = XTOPT_INVERT }
ENTRY("arp-opcode", O_OPCODE, XTTYPE_STRING),
ENTRY("arp-op", O_OPCODE, XTTYPE_STRING),
ENTRY("arp-htype", O_HTYPE, XTTYPE_STRING),
ENTRY("arp-ptype", O_PTYPE, XTTYPE_STRING),
ENTRY("arp-ip-src", O_SRC_IP, XTTYPE_HOSTMASK),
ENTRY("arp-ip-dst", O_DST_IP, XTTYPE_HOSTMASK),
ENTRY("arp-mac-src", O_SRC_MAC, XTTYPE_ETHERMACMASK),
ENTRY("arp-mac-dst", O_DST_MAC, XTTYPE_ETHERMACMASK),
ENTRY("arp-gratuitous", O_GRAT, XTTYPE_NONE),
#undef ENTRY
XTOPT_TABLEEND
};
/* a few names */
static char *opcodes[] =
{
"Request",
"Reply",
"Request_Reverse",
"Reply_Reverse",
"DRARP_Request",
"DRARP_Reply",
"DRARP_Error",
"InARP_Request",
"ARP_NAK",
};
static void brarp_print_help(void)
{
int i;
printf(
"arp options:\n"
"[!] --arp-opcode opcode : ARP opcode (integer or string)\n"
"[!] --arp-htype type : ARP hardware type (integer or string)\n"
"[!] --arp-ptype type : ARP protocol type (hexadecimal or string)\n"
"[!] --arp-ip-src address[/mask]: ARP IP source specification\n"
"[!] --arp-ip-dst address[/mask]: ARP IP target specification\n"
"[!] --arp-mac-src address[/mask]: ARP MAC source specification\n"
"[!] --arp-mac-dst address[/mask]: ARP MAC target specification\n"
"[!] --arp-gratuitous : ARP gratuitous packet\n"
" opcode strings: \n");
for (i = 0; i < ARRAY_SIZE(opcodes); i++)
printf(" %d = %s\n", i + 1, opcodes[i]);
printf(
" hardware type string: 1 = Ethernet\n"
" protocol type string: see "XT_PATH_ETHERTYPES"\n");
}
static void brarp_parse(struct xt_option_call *cb)
{
struct ebt_arp_info *arpinfo = cb->data;
struct xt_ethertypeent *ent;
long int i;
char *end;
xtables_option_parse(cb);
arpinfo->bitmask |= 1 << cb->entry->id;
if (cb->invert)
arpinfo->invflags |= 1 << cb->entry->id;
switch (cb->entry->id) {
case O_OPCODE:
i = strtol(cb->arg, &end, 10);
if (i < 0 || i >= (0x1 << 16) || *end !='\0') {
for (i = 0; i < ARRAY_SIZE(opcodes); i++)
if (!strcasecmp(opcodes[i], cb->arg))
break;
if (i == ARRAY_SIZE(opcodes))
xtables_error(PARAMETER_PROBLEM,
"Problem with specified ARP opcode");
i++;
}
arpinfo->opcode = htons(i);
break;
case O_HTYPE:
i = strtol(cb->arg, &end, 10);
if (i < 0 || i >= (0x1 << 16) || *end !='\0') {
if (!strcasecmp("Ethernet", cb->arg))
i = 1;
else
xtables_error(PARAMETER_PROBLEM,
"Problem with specified ARP hardware type");
}
arpinfo->htype = htons(i);
break;
case O_PTYPE:
i = strtol(cb->arg, &end, 16);
if (i >= 0 && i < (0x1 << 16) && *end == '\0') {
arpinfo->ptype = htons(i);
break;
}
ent = xtables_getethertypebyname(cb->arg);
if (!ent)
xtables_error(PARAMETER_PROBLEM,
"Problem with specified ARP protocol type");
arpinfo->ptype = htons(ent->e_ethertype);
break;
case O_SRC_IP:
arpinfo->saddr = cb->val.haddr.ip & cb->val.hmask.ip;
arpinfo->smsk = cb->val.hmask.ip;
break;
case O_DST_IP:
arpinfo->daddr = cb->val.haddr.ip & cb->val.hmask.ip;
arpinfo->dmsk = cb->val.hmask.ip;
break;
case O_SRC_MAC:
memcpy(arpinfo->smaddr, cb->val.ethermac, ETH_ALEN);
memcpy(arpinfo->smmsk, cb->val.ethermacmask, ETH_ALEN);
break;
case O_DST_MAC:
memcpy(arpinfo->dmaddr, cb->val.ethermac, ETH_ALEN);
memcpy(arpinfo->dmmsk, cb->val.ethermacmask, ETH_ALEN);
break;
}
}
static void brarp_print(const void *ip, const struct xt_entry_match *match, int numeric)
{
const struct ebt_arp_info *arpinfo = (struct ebt_arp_info *)match->data;
if (arpinfo->bitmask & EBT_ARP_OPCODE) {
int opcode = ntohs(arpinfo->opcode);
if (arpinfo->invflags & EBT_ARP_OPCODE)
printf("! ");
printf("--arp-op ");
if (opcode > 0 && opcode <= ARRAY_SIZE(opcodes))
printf("%s ", opcodes[opcode - 1]);
else
printf("%d ", opcode);
}
if (arpinfo->bitmask & EBT_ARP_HTYPE) {
if (arpinfo->invflags & EBT_ARP_HTYPE)
printf("! ");
printf("--arp-htype %d ", ntohs(arpinfo->htype));
}
if (arpinfo->bitmask & EBT_ARP_PTYPE) {
if (arpinfo->invflags & EBT_ARP_PTYPE)
printf("! ");
printf("--arp-ptype 0x%x ", ntohs(arpinfo->ptype));
}
if (arpinfo->bitmask & EBT_ARP_SRC_IP) {
if (arpinfo->invflags & EBT_ARP_SRC_IP)
printf("! ");
printf("--arp-ip-src %s%s ",
xtables_ipaddr_to_numeric((void *)&arpinfo->saddr),
xtables_ipmask_to_numeric((void *)&arpinfo->smsk));
}
if (arpinfo->bitmask & EBT_ARP_DST_IP) {
if (arpinfo->invflags & EBT_ARP_DST_IP)
printf("! ");
printf("--arp-ip-dst %s%s ",
xtables_ipaddr_to_numeric((void *)&arpinfo->daddr),
xtables_ipmask_to_numeric((void *)&arpinfo->dmsk));
}
if (arpinfo->bitmask & EBT_ARP_SRC_MAC) {
if (arpinfo->invflags & EBT_ARP_SRC_MAC)
printf("! ");
printf("--arp-mac-src ");
xtables_print_mac_and_mask(arpinfo->smaddr, arpinfo->smmsk);
printf(" ");
}
if (arpinfo->bitmask & EBT_ARP_DST_MAC) {
if (arpinfo->invflags & EBT_ARP_DST_MAC)
printf("! ");
printf("--arp-mac-dst ");
xtables_print_mac_and_mask(arpinfo->dmaddr, arpinfo->dmmsk);
printf(" ");
}
if (arpinfo->bitmask & EBT_ARP_GRAT) {
if (arpinfo->invflags & EBT_ARP_GRAT)
printf("! ");
printf("--arp-gratuitous ");
}
}
static struct xtables_match brarp_match = {
.name = "arp",
.version = XTABLES_VERSION,
.family = NFPROTO_BRIDGE,
.size = XT_ALIGN(sizeof(struct ebt_arp_info)),
.userspacesize = XT_ALIGN(sizeof(struct ebt_arp_info)),
.help = brarp_print_help,
.x6_parse = brarp_parse,
.print = brarp_print,
.x6_options = brarp_opts,
};
void _init(void)
{
xtables_register_match(&brarp_match);
}
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