include/net/netfilter/nf_nat.h

   1 #ifndef _NF_NAT_H
   2 #define _NF_NAT_H
   3 #include <linux/netfilter_ipv4.h>
   4 #include <net/netfilter/nf_conntrack_tuple.h>
   5
   6 #define NF_NAT_MAPPING_TYPE_MAX_NAMELEN 16
   7
   8 enum nf_nat_manip_type
   9 {
  10         IP_NAT_MANIP_SRC,
  11         IP_NAT_MANIP_DST
  12 };
  13
  14 /* SRC manip occurs POST_ROUTING or LOCAL_IN */
  15 #define HOOK2MANIP(hooknum) ((hooknum) != NF_IP_POST_ROUTING && (hooknum) != NF_IP_LOCAL_IN)
  16
  17 #define IP_NAT_RANGE_MAP_IPS 1
  18 #define IP_NAT_RANGE_PROTO_SPECIFIED 2
  19 #define IP_NAT_RANGE_PROTO_RANDOM 4
  20
  21 /* NAT sequence number modifications */
  22 struct nf_nat_seq {
  23         /* position of the last TCP sequence number modification (if any) */
  24         u_int32_t correction_pos;
  25
  26         /* sequence number offset before and after last modification */
  27         int16_t offset_before, offset_after;
  28 };
  29
  30 /* Single range specification. */
  31 struct nf_nat_range
  32 {
  33         /* Set to OR of flags above. */
  34         unsigned int flags;
  35
  36         /* Inclusive: network order. */
  37         __be32 min_ip, max_ip;
  38
  39         /* Inclusive: network order */
  40         union nf_conntrack_man_proto min, max;
  41 };
  42
  43 /* For backwards compat: don't use in modern code. */
  44 struct nf_nat_multi_range_compat
  45 {
  46         unsigned int rangesize; /* Must be 1. */
  47
  48         /* hangs off end. */
  49         struct nf_nat_range range[1];
  50 };
  51
  52 #ifdef __KERNEL__
  53 #include <linux/list.h>
  54 #include <linux/netfilter/nf_conntrack_pptp.h>
  55 #include <net/netfilter/nf_conntrack_extend.h>
  56
  57 /* per conntrack: nat application helper private data */
  58 union nf_conntrack_nat_help
  59 {
  60         /* insert nat helper private data here */
  61         struct nf_nat_pptp nat_pptp_info;
  62 };
  63
  64 struct nf_conn;
  65
  66 /* The structure embedded in the conntrack structure. */
  67 struct nf_conn_nat
  68 {
  69         struct hlist_node bysource;
  70         struct nf_nat_seq seq[IP_CT_DIR_MAX];
  71         struct nf_conn *ct;
  72         union nf_conntrack_nat_help help;
  73 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
  74     defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
  75         int masq_index;
  76 #endif
  77 };
  78
  79 /* Set up the info structure to map into this range. */
  80 extern unsigned int nf_nat_setup_info(struct nf_conn *ct,
  81                                       const struct nf_nat_range *range,
  82                                       unsigned int hooknum);
  83
  84 /* Is this tuple already taken? (not by us)*/
  85 extern int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
  86                              const struct nf_conn *ignored_conntrack);
  87
  88 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
  89 {
  90         return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
  91 }
  92
  93 #else  /* !__KERNEL__: iptables wants this to compile. */
  94 #define nf_nat_multi_range nf_nat_multi_range_compat
  95 #endif /*__KERNEL__*/
  96 #endif