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