ebtables.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 *  ebtables
  4 *
  5 *	Authors:
  6 *	Bart De Schuymer		<bdschuym@pandora.be>
  7 *
  8 *  ebtables.c,v 2.0, April, 2002
  9 *
 10 *  This code is strongly inspired by the iptables code which is
 11 *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 12 */
 13#ifndef __LINUX_BRIDGE_EFF_H
 14#define __LINUX_BRIDGE_EFF_H
 15
 16#include <linux/if.h>
 17#include <linux/if_ether.h>
 18#include <uapi/linux/netfilter_bridge/ebtables.h>
 19
 20struct ebt_match {
 21	struct list_head list;
 22	const char name[EBT_FUNCTION_MAXNAMELEN];
 23	bool (*match)(const struct sk_buff *skb, const struct net_device *in,
 24		const struct net_device *out, const struct xt_match *match,
 25		const void *matchinfo, int offset, unsigned int protoff,
 26		bool *hotdrop);
 27	bool (*checkentry)(const char *table, const void *entry,
 28		const struct xt_match *match, void *matchinfo,
 29		unsigned int hook_mask);
 30	void (*destroy)(const struct xt_match *match, void *matchinfo);
 31	unsigned int matchsize;
 32	u_int8_t revision;
 33	u_int8_t family;
 34	struct module *me;
 35};
 36
 37struct ebt_watcher {
 38	struct list_head list;
 39	const char name[EBT_FUNCTION_MAXNAMELEN];
 40	unsigned int (*target)(struct sk_buff *skb,
 41		const struct net_device *in, const struct net_device *out,
 42		unsigned int hook_num, const struct xt_target *target,
 43		const void *targinfo);
 44	bool (*checkentry)(const char *table, const void *entry,
 45		const struct xt_target *target, void *targinfo,
 46		unsigned int hook_mask);
 47	void (*destroy)(const struct xt_target *target, void *targinfo);
 48	unsigned int targetsize;
 49	u_int8_t revision;
 50	u_int8_t family;
 51	struct module *me;
 52};
 53
 54struct ebt_target {
 55	struct list_head list;
 56	const char name[EBT_FUNCTION_MAXNAMELEN];
 57	/* returns one of the standard EBT_* verdicts */
 58	unsigned int (*target)(struct sk_buff *skb,
 59		const struct net_device *in, const struct net_device *out,
 60		unsigned int hook_num, const struct xt_target *target,
 61		const void *targinfo);
 62	bool (*checkentry)(const char *table, const void *entry,
 63		const struct xt_target *target, void *targinfo,
 64		unsigned int hook_mask);
 65	void (*destroy)(const struct xt_target *target, void *targinfo);
 66	unsigned int targetsize;
 67	u_int8_t revision;
 68	u_int8_t family;
 69	struct module *me;
 70};
 71
 72/* used for jumping from and into user defined chains (udc) */
 73struct ebt_chainstack {
 74	struct ebt_entries *chaininfo; /* pointer to chain data */
 75	struct ebt_entry *e; /* pointer to entry data */
 76	unsigned int n; /* n'th entry */
 77};
 78
 79struct ebt_table_info {
 80	/* total size of the entries */
 81	unsigned int entries_size;
 82	unsigned int nentries;
 83	/* pointers to the start of the chains */
 84	struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
 85	/* room to maintain the stack used for jumping from and into udc */
 86	struct ebt_chainstack **chainstack;
 87	char *entries;
 88	struct ebt_counter counters[] ____cacheline_aligned;
 89};
 90
 91struct ebt_table {
 92	struct list_head list;
 93	char name[EBT_TABLE_MAXNAMELEN];
 94	struct ebt_replace_kernel *table;
 95	unsigned int valid_hooks;
 96	rwlock_t lock;
 97	/* the data used by the kernel */
 98	struct ebt_table_info *private;
 99	struct nf_hook_ops *ops;
100	struct module *me;
101};
102
103#define EBT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) & \
104		     ~(__alignof__(struct _xt_align)-1))
105
106extern int ebt_register_table(struct net *net,
107			      const struct ebt_table *table,
108			      const struct nf_hook_ops *ops);
109extern void ebt_unregister_table(struct net *net, const char *tablename);
110void ebt_unregister_table_pre_exit(struct net *net, const char *tablename);
111extern unsigned int ebt_do_table(void *priv, struct sk_buff *skb,
112				 const struct nf_hook_state *state);
113
114/* True if the hook mask denotes that the rule is in a base chain,
115 * used in the check() functions */
116#define BASE_CHAIN (par->hook_mask & (1 << NF_BR_NUMHOOKS))
117/* Clear the bit in the hook mask that tells if the rule is on a base chain */
118#define CLEAR_BASE_CHAIN_BIT (par->hook_mask &= ~(1 << NF_BR_NUMHOOKS))
119
120static inline bool ebt_invalid_target(int target)
121{
122	return (target < -NUM_STANDARD_TARGETS || target >= 0);
123}
124
125int ebt_register_template(const struct ebt_table *t, int(*table_init)(struct net *net));
126void ebt_unregister_template(const struct ebt_table *t);
127#endif