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 #ifndef CONFIG_IP_NF_NAT_LOCAL
  15 /* SRC manip occurs only on POST_ROUTING */
  16 #define HOOK2MANIP(hooknum) ((hooknum) != NF_IP_POST_ROUTING)
  17 #else
  18 /* SRC manip occurs POST_ROUTING or LOCAL_IN */
  19 #define HOOK2MANIP(hooknum) ((hooknum) != NF_IP_POST_ROUTING && (hooknum) != NF_IP_LOCAL_IN)
  20 #endif
  21
  22 #define IP_NAT_RANGE_MAP_IPS 1
  23 #define IP_NAT_RANGE_PROTO_SPECIFIED 2
  24 /* Used internally by get_unique_tuple(). */
  25 #define IP_NAT_RANGE_FULL 4
  26
  27 /* NAT sequence number modifications */
  28 struct ip_nat_seq {
  29         /* position of the last TCP sequence number
  30          * modification (if any) */
  31         u_int32_t correction_pos;
  32         /* sequence number offset before and after last modification */
  33         int32_t offset_before, offset_after;
  34 };
  35
  36 /* Single range specification. */
  37 struct ip_nat_range
  38 {
  39         /* Set to OR of flags above. */
  40         unsigned int flags;
  41
  42         /* Inclusive: network order. */
  43         u_int32_t min_ip, max_ip;
  44
  45         /* Inclusive: network order */
  46         union ip_conntrack_manip_proto min, max;
  47 };
  48
  49 /* A range consists of an array of 1 or more ip_nat_range */
  50 struct ip_nat_multi_range
  51 {
  52         unsigned int rangesize;
  53
  54         /* hangs off end. */
  55         struct ip_nat_range range[1];
  56 };
  57
  58 /* Worst case: local-out manip + 1 post-routing, and reverse dirn. */
  59 #define IP_NAT_MAX_MANIPS (2*3)
  60
  61 struct ip_nat_info_manip
  62 {
  63         /* The direction. */
  64         u_int8_t direction;
  65
  66         /* Which hook the manipulation happens on. */
  67         u_int8_t hooknum;
  68
  69         /* The manipulation type. */
  70         u_int8_t maniptype;
  71
  72         /* Manipulations to occur at each conntrack in this dirn. */
  73         struct ip_conntrack_manip manip;
  74 };
  75
  76 #ifdef __KERNEL__
  77 #include <linux/list.h>
  78 #include <linux/netfilter_ipv4/lockhelp.h>
  79
  80 /* Protects NAT hash tables, and NAT-private part of conntracks. */
  81 DECLARE_RWLOCK_EXTERN(ip_nat_lock);
  82
  83 /* The structure embedded in the conntrack structure. */
  84 struct ip_nat_info
  85 {
  86         /* Set to zero when conntrack created: bitmask of maniptypes */
  87         u_int16_t initialized;
  88
  89         u_int16_t num_manips;
  90
  91         /* Manipulations to be done on this conntrack. */
  92         struct ip_nat_info_manip manips[IP_NAT_MAX_MANIPS];
  93
  94         struct list_head bysource, byipsproto;
  95
  96         /* Helper (NULL if none). */
  97         struct ip_nat_helper *helper;
  98
  99         struct ip_nat_seq seq[IP_CT_DIR_MAX];
 100 };
 101
 102 /* Set up the info structure to map into this range. */
 103 extern unsigned int ip_nat_setup_info(struct ip_conntrack *conntrack,
 104                                       const struct ip_nat_multi_range *mr,
 105                                       unsigned int hooknum);
 106
 107 /* Is this tuple already taken? (not by us)*/
 108 extern int ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple,
 109                              const struct ip_conntrack *ignored_conntrack);
 110
 111 /* Calculate relative checksum. */
 112 extern u_int16_t ip_nat_cheat_check(u_int32_t oldvalinv,
 113                                     u_int32_t newval,
 114                                     u_int16_t oldcheck);
 115 #endif /*__KERNEL__*/
 116 #endif