include/linux/netfilter_ipv4/ip_nat.h

   1 #ifndef _IP_NAT_H
   2 #define _IP_NAT_H
   3 #include <linux/netfilter_ipv4.h>
   4 #include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
   5
   6 #define IP_NAT_MAPPING_TYPE_MAX_NAMELEN 16
   7
   8 enum ip_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
  20 /* NAT sequence number modifications */
  21 struct ip_nat_seq {
  22         /* position of the last TCP sequence number
  23          * modification (if any) */
  24         u_int32_t correction_pos;
  25         /* sequence number offset before and after last modification */
  26         int16_t offset_before, offset_after;
  27 };
  28
  29 /* Single range specification. */
  30 struct ip_nat_range
  31 {
  32         /* Set to OR of flags above. */
  33         unsigned int flags;
  34
  35         /* Inclusive: network order. */
  36         u_int32_t min_ip, max_ip;
  37
  38         /* Inclusive: network order */
  39         union ip_conntrack_manip_proto min, max;
  40 };
  41
  42 /* For backwards compat: don't use in modern code. */
  43 struct ip_nat_multi_range_compat
  44 {
  45         unsigned int rangesize; /* Must be 1. */
  46
  47         /* hangs off end. */
  48         struct ip_nat_range range[1];
  49 };
  50
  51 #ifdef __KERNEL__
  52 #include <linux/list.h>
  53
  54 /* Protects NAT hash tables, and NAT-private part of conntracks. */
  55 extern rwlock_t ip_nat_lock;
  56
  57 /* The structure embedded in the conntrack structure. */
  58 struct ip_nat_info
  59 {
  60         struct list_head bysource;
  61         struct ip_nat_seq seq[IP_CT_DIR_MAX];
  62 };
  63
  64 struct ip_conntrack;
  65
  66 /* Set up the info structure to map into this range. */
  67 extern unsigned int ip_nat_setup_info(struct ip_conntrack *conntrack,
  68                                       const struct ip_nat_range *range,
  69                                       unsigned int hooknum);
  70
  71 /* Is this tuple already taken? (not by us)*/
  72 extern int ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple,
  73                              const struct ip_conntrack *ignored_conntrack);
  74
  75 /* Calculate relative checksum. */
  76 extern u_int16_t ip_nat_cheat_check(u_int32_t oldvalinv,
  77                                     u_int32_t newval,
  78                                     u_int16_t oldcheck);
  79 #else  /* !__KERNEL__: iptables wants this to compile. */
  80 #define ip_nat_multi_range ip_nat_multi_range_compat
  81 #endif /*__KERNEL__*/
  82 #endif