// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ebtable_broute
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*
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* Authors:
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* Bart De Schuymer <bdschuym@pandora.be>
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*
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* April, 2002
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*
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* This table lets you choose between routing and bridging for frames
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* entering on a bridge enslaved nic. This table is traversed before any
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* other ebtables table. See net/bridge/br_input.c.
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*/
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/module.h>
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#include <linux/if_bridge.h>
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#include "../br_private.h"
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/* EBT_ACCEPT means the frame will be bridged
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* EBT_DROP means the frame will be routed
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*/
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static struct ebt_entries initial_chain = {
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.name = "BROUTING",
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.policy = EBT_ACCEPT,
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};
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static struct ebt_replace_kernel initial_table = {
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.name = "broute",
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.valid_hooks = 1 << NF_BR_BROUTING,
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.entries_size = sizeof(struct ebt_entries),
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.hook_entry = {
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[NF_BR_BROUTING] = &initial_chain,
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},
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.entries = (char *)&initial_chain,
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};
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static const struct ebt_table broute_table = {
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.name = "broute",
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.table = &initial_table,
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.valid_hooks = 1 << NF_BR_BROUTING,
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.me = THIS_MODULE,
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};
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static unsigned int ebt_broute(void *priv, struct sk_buff *skb,
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const struct nf_hook_state *s)
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{
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struct net_bridge_port *p = br_port_get_rcu(skb->dev);
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struct nf_hook_state state;
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unsigned char *dest;
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int ret;
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if (!p || p->state != BR_STATE_FORWARDING)
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return NF_ACCEPT;
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nf_hook_state_init(&state, NF_BR_BROUTING,
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NFPROTO_BRIDGE, s->in, NULL, NULL,
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s->net, NULL);
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ret = ebt_do_table(skb, &state, state.net->xt.broute_table);
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if (ret != NF_DROP)
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return ret;
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/* DROP in ebtables -t broute means that the
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* skb should be routed, not bridged.
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* This is awkward, but can't be changed for compatibility
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* reasons.
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*
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* We map DROP to ACCEPT and set the ->br_netfilter_broute flag.
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*/
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BR_INPUT_SKB_CB(skb)->br_netfilter_broute = 1;
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/* undo PACKET_HOST mangling done in br_input in case the dst
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* address matches the logical bridge but not the port.
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*/
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dest = eth_hdr(skb)->h_dest;
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if (skb->pkt_type == PACKET_HOST &&
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!ether_addr_equal(skb->dev->dev_addr, dest) &&
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ether_addr_equal(p->br->dev->dev_addr, dest))
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skb->pkt_type = PACKET_OTHERHOST;
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return NF_ACCEPT;
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}
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static const struct nf_hook_ops ebt_ops_broute = {
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.hook = ebt_broute,
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.pf = NFPROTO_BRIDGE,
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.hooknum = NF_BR_PRE_ROUTING,
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.priority = NF_BR_PRI_FIRST,
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};
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static int __net_init broute_net_init(struct net *net)
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{
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return ebt_register_table(net, &broute_table, &ebt_ops_broute,
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&net->xt.broute_table);
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}
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static void __net_exit broute_net_pre_exit(struct net *net)
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{
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ebt_unregister_table_pre_exit(net, "broute", &ebt_ops_broute);
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}
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static void __net_exit broute_net_exit(struct net *net)
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{
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ebt_unregister_table(net, net->xt.broute_table);
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}
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static struct pernet_operations broute_net_ops = {
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.init = broute_net_init,
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.exit = broute_net_exit,
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.pre_exit = broute_net_pre_exit,
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};
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static int __init ebtable_broute_init(void)
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{
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return register_pernet_subsys(&broute_net_ops);
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}
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static void __exit ebtable_broute_fini(void)
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{
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unregister_pernet_subsys(&broute_net_ops);
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}
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module_init(ebtable_broute_init);
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module_exit(ebtable_broute_fini);
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MODULE_LICENSE("GPL");
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