diff options
Diffstat (limited to 'net/bridge/netfilter/ebtable_broute.c')
-rw-r--r-- | net/bridge/netfilter/ebtable_broute.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebtable_broute.c b/net/bridge/netfilter/ebtable_broute.c new file mode 100644 index 000000000..8f1925302 --- /dev/null +++ b/net/bridge/netfilter/ebtable_broute.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ebtable_broute + * + * Authors: + * Bart De Schuymer <bdschuym@pandora.be> + * + * April, 2002 + * + * This table lets you choose between routing and bridging for frames + * entering on a bridge enslaved nic. This table is traversed before any + * other ebtables table. See net/bridge/br_input.c. + */ + +#include <linux/netfilter_bridge/ebtables.h> +#include <linux/module.h> +#include <linux/if_bridge.h> + +#include "../br_private.h" + +/* EBT_ACCEPT means the frame will be bridged + * EBT_DROP means the frame will be routed + */ +static struct ebt_entries initial_chain = { + .name = "BROUTING", + .policy = EBT_ACCEPT, +}; + +static struct ebt_replace_kernel initial_table = { + .name = "broute", + .valid_hooks = 1 << NF_BR_BROUTING, + .entries_size = sizeof(struct ebt_entries), + .hook_entry = { + [NF_BR_BROUTING] = &initial_chain, + }, + .entries = (char *)&initial_chain, +}; + +static const struct ebt_table broute_table = { + .name = "broute", + .table = &initial_table, + .valid_hooks = 1 << NF_BR_BROUTING, + .me = THIS_MODULE, +}; + +static unsigned int ebt_broute(void *priv, struct sk_buff *skb, + const struct nf_hook_state *s) +{ + struct net_bridge_port *p = br_port_get_rcu(skb->dev); + struct nf_hook_state state; + unsigned char *dest; + int ret; + + if (!p || p->state != BR_STATE_FORWARDING) + return NF_ACCEPT; + + nf_hook_state_init(&state, NF_BR_BROUTING, + NFPROTO_BRIDGE, s->in, NULL, NULL, + s->net, NULL); + + ret = ebt_do_table(priv, skb, &state); + if (ret != NF_DROP) + return ret; + + /* DROP in ebtables -t broute means that the + * skb should be routed, not bridged. + * This is awkward, but can't be changed for compatibility + * reasons. + * + * We map DROP to ACCEPT and set the ->br_netfilter_broute flag. + */ + BR_INPUT_SKB_CB(skb)->br_netfilter_broute = 1; + + /* undo PACKET_HOST mangling done in br_input in case the dst + * address matches the logical bridge but not the port. + */ + dest = eth_hdr(skb)->h_dest; + if (skb->pkt_type == PACKET_HOST && + !ether_addr_equal(skb->dev->dev_addr, dest) && + ether_addr_equal(p->br->dev->dev_addr, dest)) + skb->pkt_type = PACKET_OTHERHOST; + + return NF_ACCEPT; +} + +static const struct nf_hook_ops ebt_ops_broute = { + .hook = ebt_broute, + .pf = NFPROTO_BRIDGE, + .hooknum = NF_BR_PRE_ROUTING, + .priority = NF_BR_PRI_FIRST, +}; + +static int broute_table_init(struct net *net) +{ + return ebt_register_table(net, &broute_table, &ebt_ops_broute); +} + +static void __net_exit broute_net_pre_exit(struct net *net) +{ + ebt_unregister_table_pre_exit(net, "broute"); +} + +static void __net_exit broute_net_exit(struct net *net) +{ + ebt_unregister_table(net, "broute"); +} + +static struct pernet_operations broute_net_ops = { + .exit = broute_net_exit, + .pre_exit = broute_net_pre_exit, +}; + +static int __init ebtable_broute_init(void) +{ + int ret = ebt_register_template(&broute_table, broute_table_init); + + if (ret) + return ret; + + ret = register_pernet_subsys(&broute_net_ops); + if (ret) { + ebt_unregister_template(&broute_table); + return ret; + } + + return 0; +} + +static void __exit ebtable_broute_fini(void) +{ + unregister_pernet_subsys(&broute_net_ops); + ebt_unregister_template(&broute_table); +} + +module_init(ebtable_broute_init); +module_exit(ebtable_broute_fini); +MODULE_LICENSE("GPL"); |