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