cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

ebt_dnat.c (2489B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  ebt_dnat
      4 *
      5 *	Authors:
      6 *	Bart De Schuymer <bdschuym@pandora.be>
      7 *
      8 *  June, 2002
      9 *
     10 */
     11#include <linux/module.h>
     12#include <net/sock.h>
     13#include "../br_private.h"
     14#include <linux/netfilter.h>
     15#include <linux/netfilter/x_tables.h>
     16#include <linux/netfilter_bridge/ebtables.h>
     17#include <linux/netfilter_bridge/ebt_nat.h>
     18
     19static unsigned int
     20ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par)
     21{
     22	const struct ebt_nat_info *info = par->targinfo;
     23
     24	if (skb_ensure_writable(skb, 0))
     25		return EBT_DROP;
     26
     27	ether_addr_copy(eth_hdr(skb)->h_dest, info->mac);
     28
     29	if (is_multicast_ether_addr(info->mac)) {
     30		if (is_broadcast_ether_addr(info->mac))
     31			skb->pkt_type = PACKET_BROADCAST;
     32		else
     33			skb->pkt_type = PACKET_MULTICAST;
     34	} else {
     35		const struct net_device *dev;
     36
     37		switch (xt_hooknum(par)) {
     38		case NF_BR_BROUTING:
     39			dev = xt_in(par);
     40			break;
     41		case NF_BR_PRE_ROUTING:
     42			dev = br_port_get_rcu(xt_in(par))->br->dev;
     43			break;
     44		default:
     45			dev = NULL;
     46			break;
     47		}
     48
     49		if (!dev) /* NF_BR_LOCAL_OUT */
     50			return info->target;
     51
     52		if (ether_addr_equal(info->mac, dev->dev_addr))
     53			skb->pkt_type = PACKET_HOST;
     54		else
     55			skb->pkt_type = PACKET_OTHERHOST;
     56	}
     57
     58	return info->target;
     59}
     60
     61static int ebt_dnat_tg_check(const struct xt_tgchk_param *par)
     62{
     63	const struct ebt_nat_info *info = par->targinfo;
     64	unsigned int hook_mask;
     65
     66	if (BASE_CHAIN && info->target == EBT_RETURN)
     67		return -EINVAL;
     68
     69	hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
     70	if ((strcmp(par->table, "nat") != 0 ||
     71	    (hook_mask & ~((1 << NF_BR_PRE_ROUTING) |
     72	    (1 << NF_BR_LOCAL_OUT)))) &&
     73	    (strcmp(par->table, "broute") != 0 ||
     74	    hook_mask & ~(1 << NF_BR_BROUTING)))
     75		return -EINVAL;
     76	if (ebt_invalid_target(info->target))
     77		return -EINVAL;
     78	return 0;
     79}
     80
     81static struct xt_target ebt_dnat_tg_reg __read_mostly = {
     82	.name		= "dnat",
     83	.revision	= 0,
     84	.family		= NFPROTO_BRIDGE,
     85	.hooks		= (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
     86			  (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING),
     87	.target		= ebt_dnat_tg,
     88	.checkentry	= ebt_dnat_tg_check,
     89	.targetsize	= sizeof(struct ebt_nat_info),
     90	.me		= THIS_MODULE,
     91};
     92
     93static int __init ebt_dnat_init(void)
     94{
     95	return xt_register_target(&ebt_dnat_tg_reg);
     96}
     97
     98static void __exit ebt_dnat_fini(void)
     99{
    100	xt_unregister_target(&ebt_dnat_tg_reg);
    101}
    102
    103module_init(ebt_dnat_init);
    104module_exit(ebt_dnat_fini);
    105MODULE_DESCRIPTION("Ebtables: Destination MAC address translation");
    106MODULE_LICENSE("GPL");