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         IP_NAT_MANIP_SRC,
  10         IP_NAT_MANIP_DST
  11 };
  12
  13 /* SRC manip occurs POST_ROUTING or LOCAL_IN */
  14 #define HOOK2MANIP(hooknum) ((hooknum) != NF_INET_POST_ROUTING && \
  15                              (hooknum) != NF_INET_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 #define IP_NAT_RANGE_PERSISTENT 8
  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         /* 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         unsigned int rangesize; /* Must be 1. */
  46
  47         /* hangs off end. */
  48         struct nf_nat_range range[1];
  49 };
  50
  51 #include <linux/list.h>
  52 #include <linux/netfilter/nf_conntrack_pptp.h>
  53 #include <net/netfilter/nf_conntrack_extend.h>
  54
  55 /* per conntrack: nat application helper private data */
  56 union nf_conntrack_nat_help {
  57         /* insert nat helper private data here */
  58 #if defined(CONFIG_NF_NAT_PPTP) || defined(CONFIG_NF_NAT_PPTP_MODULE)
  59         struct nf_nat_pptp nat_pptp_info;
  60 #endif
  61 };
  62
  63 struct nf_conn;
  64
  65 /* The structure embedded in the conntrack structure. */
  66 struct nf_conn_nat {
  67         struct hlist_node bysource;
  68         struct nf_nat_seq seq[IP_CT_DIR_MAX];
  69         struct nf_conn *ct;
  70         union nf_conntrack_nat_help help;
  71 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
  72     defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
  73         int masq_index;
  74 #endif
  75 };
  76
  77 /* Set up the info structure to map into this range. */
  78 extern unsigned int nf_nat_setup_info(struct nf_conn *ct,
  79                                       const struct nf_nat_range *range,
  80                                       enum nf_nat_manip_type maniptype);
  81
  82 /* Is this tuple already taken? (not by us)*/
  83 extern int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
  84                              const struct nf_conn *ignored_conntrack);
  85
  86 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
  87 {
  88 #if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
  89         return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
  90 #else
  91         return NULL;
  92 #endif
  93 }
  94
  95 #endif