cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ebtable_broute.c (3455B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  ebtable_broute
      4 *
      5 *	Authors:
      6 *	Bart De Schuymer <bdschuym@pandora.be>
      7 *
      8 *  April, 2002
      9 *
     10 *  This table lets you choose between routing and bridging for frames
     11 *  entering on a bridge enslaved nic. This table is traversed before any
     12 *  other ebtables table. See net/bridge/br_input.c.
     13 */
     14
     15#include <linux/netfilter_bridge/ebtables.h>
     16#include <linux/module.h>
     17#include <linux/if_bridge.h>
     18
     19#include "../br_private.h"
     20
     21/* EBT_ACCEPT means the frame will be bridged
     22 * EBT_DROP means the frame will be routed
     23 */
     24static struct ebt_entries initial_chain = {
     25	.name		= "BROUTING",
     26	.policy		= EBT_ACCEPT,
     27};
     28
     29static struct ebt_replace_kernel initial_table = {
     30	.name		= "broute",
     31	.valid_hooks	= 1 << NF_BR_BROUTING,
     32	.entries_size	= sizeof(struct ebt_entries),
     33	.hook_entry	= {
     34		[NF_BR_BROUTING]	= &initial_chain,
     35	},
     36	.entries	= (char *)&initial_chain,
     37};
     38
     39static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
     40{
     41	if (valid_hooks & ~(1 << NF_BR_BROUTING))
     42		return -EINVAL;
     43	return 0;
     44}
     45
     46static const struct ebt_table broute_table = {
     47	.name		= "broute",
     48	.table		= &initial_table,
     49	.valid_hooks	= 1 << NF_BR_BROUTING,
     50	.check		= check,
     51	.me		= THIS_MODULE,
     52};
     53
     54static unsigned int ebt_broute(void *priv, struct sk_buff *skb,
     55			       const struct nf_hook_state *s)
     56{
     57	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
     58	struct nf_hook_state state;
     59	unsigned char *dest;
     60	int ret;
     61
     62	if (!p || p->state != BR_STATE_FORWARDING)
     63		return NF_ACCEPT;
     64
     65	nf_hook_state_init(&state, NF_BR_BROUTING,
     66			   NFPROTO_BRIDGE, s->in, NULL, NULL,
     67			   s->net, NULL);
     68
     69	ret = ebt_do_table(priv, skb, &state);
     70	if (ret != NF_DROP)
     71		return ret;
     72
     73	/* DROP in ebtables -t broute means that the
     74	 * skb should be routed, not bridged.
     75	 * This is awkward, but can't be changed for compatibility
     76	 * reasons.
     77	 *
     78	 * We map DROP to ACCEPT and set the ->br_netfilter_broute flag.
     79	 */
     80	BR_INPUT_SKB_CB(skb)->br_netfilter_broute = 1;
     81
     82	/* undo PACKET_HOST mangling done in br_input in case the dst
     83	 * address matches the logical bridge but not the port.
     84	 */
     85	dest = eth_hdr(skb)->h_dest;
     86	if (skb->pkt_type == PACKET_HOST &&
     87	    !ether_addr_equal(skb->dev->dev_addr, dest) &&
     88	     ether_addr_equal(p->br->dev->dev_addr, dest))
     89		skb->pkt_type = PACKET_OTHERHOST;
     90
     91	return NF_ACCEPT;
     92}
     93
     94static const struct nf_hook_ops ebt_ops_broute = {
     95	.hook		= ebt_broute,
     96	.pf		= NFPROTO_BRIDGE,
     97	.hooknum	= NF_BR_PRE_ROUTING,
     98	.priority	= NF_BR_PRI_FIRST,
     99};
    100
    101static int broute_table_init(struct net *net)
    102{
    103	return ebt_register_table(net, &broute_table, &ebt_ops_broute);
    104}
    105
    106static void __net_exit broute_net_pre_exit(struct net *net)
    107{
    108	ebt_unregister_table_pre_exit(net, "broute");
    109}
    110
    111static void __net_exit broute_net_exit(struct net *net)
    112{
    113	ebt_unregister_table(net, "broute");
    114}
    115
    116static struct pernet_operations broute_net_ops = {
    117	.exit = broute_net_exit,
    118	.pre_exit = broute_net_pre_exit,
    119};
    120
    121static int __init ebtable_broute_init(void)
    122{
    123	int ret = ebt_register_template(&broute_table, broute_table_init);
    124
    125	if (ret)
    126		return ret;
    127
    128	ret = register_pernet_subsys(&broute_net_ops);
    129	if (ret) {
    130		ebt_unregister_template(&broute_table);
    131		return ret;
    132	}
    133
    134	return 0;
    135}
    136
    137static void __exit ebtable_broute_fini(void)
    138{
    139	unregister_pernet_subsys(&broute_net_ops);
    140	ebt_unregister_template(&broute_table);
    141}
    142
    143module_init(ebtable_broute_init);
    144module_exit(ebtable_broute_fini);
    145MODULE_LICENSE("GPL");