1#ifndef _NF_NAT_H
2#define _NF_NAT_H
3#include <linux/netfilter_ipv4.h>
4#include <linux/netfilter/nf_nat.h>
5#include <net/netfilter/nf_conntrack_tuple.h>
6
7enum nf_nat_manip_type {
8	NF_NAT_MANIP_SRC,
9	NF_NAT_MANIP_DST
10};
11
12/* SRC manip occurs POST_ROUTING or LOCAL_IN */
13#define HOOK2MANIP(hooknum) ((hooknum) != NF_INET_POST_ROUTING && \
14			     (hooknum) != NF_INET_LOCAL_IN)
15
16#include <linux/list.h>
17#include <linux/netfilter/nf_conntrack_pptp.h>
18#include <net/netfilter/nf_conntrack_extend.h>
19
20/* per conntrack: nat application helper private data */
21union nf_conntrack_nat_help {
22	/* insert nat helper private data here */
23#if defined(CONFIG_NF_NAT_PPTP) || defined(CONFIG_NF_NAT_PPTP_MODULE)
24	struct nf_nat_pptp nat_pptp_info;
25#endif
26};
27
28struct nf_conn;
29
30/* The structure embedded in the conntrack structure. */
31struct nf_conn_nat {
32	struct hlist_node bysource;
33	struct nf_conn *ct;
34	union nf_conntrack_nat_help help;
35#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV4) || \
36    IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV6)
37	int masq_index;
38#endif
39};
40
41/* Set up the info structure to map into this range. */
42unsigned int nf_nat_setup_info(struct nf_conn *ct,
43			       const struct nf_nat_range *range,
44			       enum nf_nat_manip_type maniptype);
45
46extern unsigned int nf_nat_alloc_null_binding(struct nf_conn *ct,
47					      unsigned int hooknum);
48
49struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct);
50
51/* Is this tuple already taken? (not by us)*/
52int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
53		      const struct nf_conn *ignored_conntrack);
54
55static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
56{
57#if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
58	return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
59#else
60	return NULL;
61#endif
62}
63
64static inline bool nf_nat_oif_changed(unsigned int hooknum,
65				      enum ip_conntrack_info ctinfo,
66				      struct nf_conn_nat *nat,
67				      const struct net_device *out)
68{
69#if IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV4) || \
70    IS_ENABLED(CONFIG_NF_NAT_MASQUERADE_IPV6)
71	return nat->masq_index && hooknum == NF_INET_POST_ROUTING &&
72	       CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL &&
73	       nat->masq_index != out->ifindex;
74#else
75	return false;
76#endif
77}
78
79#endif
80