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 
7 enum 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 /* NAT sequence number modifications */
17 struct nf_nat_seq {
18 	/* position of the last TCP sequence number modification (if any) */
19 	u_int32_t correction_pos;
20 
21 	/* sequence number offset before and after last modification */
22 	int16_t offset_before, offset_after;
23 };
24 
25 #include <linux/list.h>
26 #include <linux/netfilter/nf_conntrack_pptp.h>
27 #include <net/netfilter/nf_conntrack_extend.h>
28 
29 /* per conntrack: nat application helper private data */
30 union nf_conntrack_nat_help {
31 	/* insert nat helper private data here */
32 #if defined(CONFIG_NF_NAT_PPTP) || defined(CONFIG_NF_NAT_PPTP_MODULE)
33 	struct nf_nat_pptp nat_pptp_info;
34 #endif
35 };
36 
37 struct nf_conn;
38 
39 /* The structure embedded in the conntrack structure. */
40 struct nf_conn_nat {
41 	struct hlist_node bysource;
42 	struct nf_nat_seq seq[IP_CT_DIR_MAX];
43 	struct nf_conn *ct;
44 	union nf_conntrack_nat_help help;
45 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
46     defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
47 	int masq_index;
48 #endif
49 };
50 
51 /* Set up the info structure to map into this range. */
52 extern unsigned int nf_nat_setup_info(struct nf_conn *ct,
53 				      const struct nf_nat_ipv4_range *range,
54 				      enum nf_nat_manip_type maniptype);
55 
56 /* Is this tuple already taken? (not by us)*/
57 extern int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
58 			     const struct nf_conn *ignored_conntrack);
59 
nfct_nat(const struct nf_conn * ct)60 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
61 {
62 #if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
63 	return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
64 #else
65 	return NULL;
66 #endif
67 }
68 
69 #endif
70