/* SPDX-License-Identifier: GPL-2.0 */
/*
* connection tracking helpers.
*
* 16 Dec 2003: Yasuyuki Kozakai @USAGI <[email protected]>
* - generalize L3 protocol dependent part.
*
* Derived from include/linux/netfiter_ipv4/ip_conntrack_helper.h
*/
#ifndef _NF_CONNTRACK_HELPER_H
#define _NF_CONNTRACK_HELPER_H
#include <linux/refcount.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_conntrack_expect.h>
#define NF_NAT_HELPER_PREFIX "ip_nat_"
#define NF_NAT_HELPER_NAME(name) NF_NAT_HELPER_PREFIX name
#define MODULE_ALIAS_NF_NAT_HELPER(name) \
MODULE_ALIAS(NF_NAT_HELPER_NAME(name))
struct module;
enum nf_ct_helper_flags {
NF_CT_HELPER_F_USERSPACE = (1 << 0),
NF_CT_HELPER_F_CONFIGURED = (1 << 1),
};
#define NF_CT_HELPER_NAME_LEN 16
struct nf_conntrack_helper {
struct hlist_node hnode; /* Internal use. */
char name[NF_CT_HELPER_NAME_LEN]; /* name of the module */
refcount_t refcnt;
struct module *me; /* pointer to self */
const struct nf_conntrack_expect_policy *expect_policy;
/* Tuple of things we will help (compared against server response) */
struct nf_conntrack_tuple tuple;
/* Function to call when data passes; return verdict, or -1 to
invalidate. */
int (*help)(struct sk_buff *skb,
unsigned int protoff,
struct nf_conn *ct,
enum ip_conntrack_info conntrackinfo);
void (*destroy)(struct nf_conn *ct);
int (*from_nlattr)(struct nlattr *attr, struct nf_conn *ct);
int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
unsigned int expect_class_max;
unsigned int flags;
/* For user-space helpers: */
unsigned int queue_num;
/* length of userspace private data stored in nf_conn_help->data */
u16 data_len;
/* name of NAT helper module */
char nat_mod_name[NF_CT_HELPER_NAME_LEN];
};
/* Must be kept in sync with the classes defined by helpers */
#define NF_CT_MAX_EXPECT_CLASSES 4
/* nf_conn feature for connections that have a helper */
struct nf_conn_help {
/* Helper. if any */
struct nf_conntrack_helper __rcu *helper;
struct hlist_head expectations;
/* Current number of expected connections */
u8 expecting[NF_CT_MAX_EXPECT_CLASSES];
/* private helper information. */
char data[32] __aligned(8);
};
#define NF_CT_HELPER_BUILD_BUG_ON(structsize) \
BUILD_BUG_ON((structsize) > sizeof_field(struct nf_conn_help, data))
struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
u16 l3num, u8 protonum);
struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
u16 l3num,
u8 protonum);
void nf_conntrack_helper_put(struct nf_conntrack_helper *helper);
void nf_ct_helper_init(struct nf_conntrack_helper *helper,
u16 l3num, u16 protonum, const char *name,
u16 default_port, u16 spec_port, u32 id,
const struct nf_conntrack_expect_policy *exp_pol,
u32 expect_class_max,
int (*help)(struct sk_buff *skb, unsigned int protoff,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo),
int (*from_nlattr)(struct nlattr *attr,
struct nf_conn *ct),
struct module *module);
int nf_conntrack_helper_register(struct nf_conntrack_helper *);
void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
int nf_conntrack_helpers_register(struct nf_conntrack_helper *, unsigned int);
void nf_conntrack_helpers_unregister(struct nf_conntrack_helper *,
unsigned int);
struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
gfp_t flags);
int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, u16 proto);
int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family,
u8 proto, bool nat, struct nf_conntrack_helper **hp);
void nf_ct_helper_destroy(struct nf_conn *ct);
static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
{
return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
}
static inline void *nfct_help_data(const struct nf_conn *ct)
{
struct nf_conn_help *help;
help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
return (void *)help->data;
}
int nf_conntrack_helper_init(void);
void nf_conntrack_helper_fini(void);
int nf_conntrack_broadcast_help(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
unsigned int timeout);
struct nf_ct_helper_expectfn {
struct list_head head;
const char *name;
void (*expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
};
__printf(3,4)
void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
const char *fmt, ...);
void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n);
void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n);
struct nf_ct_helper_expectfn *
nf_ct_helper_expectfn_find_by_name(const char *name);
struct nf_ct_helper_expectfn *
nf_ct_helper_expectfn_find_by_symbol(const void *symbol);
extern struct hlist_head *nf_ct_helper_hash;
extern unsigned int nf_ct_helper_hsize;
struct nf_conntrack_nat_helper {
struct list_head list;
char mod_name[NF_CT_HELPER_NAME_LEN]; /* module name */
struct module *module; /* pointer to self */
};
#define NF_CT_NAT_HELPER_INIT(name) \
{ \
.mod_name = NF_NAT_HELPER_NAME(name), \
.module = THIS_MODULE \
}
void nf_nat_helper_register(struct nf_conntrack_nat_helper *nat);
void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat);
int nf_nat_helper_try_module_get(const char *name, u16 l3num,
u8 protonum);
void nf_nat_helper_put(struct nf_conntrack_helper *helper);
#endif /*_NF_CONNTRACK_HELPER_H*/
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