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