lib/ipv4.h

   1 /*
   2  *      BIRD -- IP Addresses et Cetera for IPv4
   3  *
   4  *      (c) 1998--1999 Martin Mares <mj@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #ifndef _BIRD_IPV4_H_
  10 #define _BIRD_IPV4_H_
  11
  12 #include "lib/endian.h"
  13 #include "lib/bitops.h"
  14 #include "lib/unaligned.h"
  15
  16 #ifdef DEBUGGING
  17
  18 /*
  19  *      Use the structural representation when you want to make sure
  20  *      nobody unauthorized attempts to handle ip_addr as number.
  21  */
  22
  23 typedef struct ipv4_addr {
  24   u32 addr;
  25 } ip_addr;
  26
  27 #define _I(x) (x).addr
  28 #define _MI(x) ((struct ipv4_addr) { x })
  29
  30 #else
  31
  32 typedef u32 ip_addr;
  33
  34 #define _I(x) (x)
  35 #define _MI(x) (x)
  36
  37 #endif
  38
  39 #define MAX_PREFIX_LENGTH 32
  40 #define BITS_PER_IP_ADDRESS 32
  41 #define STD_ADDRESS_P_LENGTH 15
  42 #define SIZE_OF_IP_HEADER 24
  43
  44 #define IPA_NONE (_MI(0))
  45
  46 #define ipa_equal(x,y) (_I(x) == _I(y))
  47 #define ipa_nonzero(x) _I(x)
  48 #define ipa_and(x,y) _MI(_I(x) & _I(y))
  49 #define ipa_or(x,y) _MI(_I(x) | _I(y))
  50 #define ipa_xor(x,y) _MI(_I(x) ^ _I(y))
  51 #define ipa_not(x) _MI(~_I(x))
  52 #define ipa_mkmask(x) _MI(u32_mkmask(x))
  53 #define ipa_mklen(x) u32_masklen(_I(x))
  54 #define ipa_hash(x) ipv4_hash(_I(x))
  55 #define ipa_hash32(x) ipv4_hash32(_I(x))
  56 #define ipa_hton(x) x = _MI(htonl(_I(x)))
  57 #define ipa_ntoh(x) x = _MI(ntohl(_I(x)))
  58 #define ipa_classify(x) ipv4_classify(_I(x))
  59 #define ipa_has_link_scope(x) ipv4_has_link_scope(_I(x))
  60 #define ipa_opposite_m1(x) _MI(_I(x) ^ 1)
  61 #define ipa_opposite_m2(x) _MI(_I(x) ^ 3)
  62 #define ipa_class_mask(x) _MI(ipv4_class_mask(_I(x)))
  63 #define ipa_from_u32(x) _MI(x)
  64 #define ipa_to_u32(x) _I(x)
  65 #define ipa_compare(x,y) ipv4_compare(_I(x),_I(y))
  66 /* ipa_pxlen() requires that x != y */
  67 #define ipa_pxlen(x, y) ipv4_pxlen(_I(x), _I(y))
  68 #define ipa_getbit(x, y) (_I(x) & (0x80000000 >> (y)))
  69 #define ipa_put_addr(x, y) ipv4_put_addr(x, y)
  70
  71 #define ip_skip_header(x, y) ipv4_skip_header(x, y)
  72
  73 int ipv4_classify(u32);
  74 u32 ipv4_class_mask(u32);
  75 byte *ipv4_skip_header(byte *, int *);
  76
  77 static inline int ipv4_has_link_scope(u32 a UNUSED)
  78 {
  79   return 0;
  80 }
  81
  82 static inline unsigned ipv4_hash(u32 a)
  83 {
  84   /* Returns a 16-bit value */
  85   a ^= a >> 16;
  86   a ^= a << 10;
  87   return a & 0xffff;
  88 }
  89
  90 static inline u32 ipv4_hash32(u32 a)
  91 {
  92   /* Returns a 32-bit value, although low-order bits are not mixed */
  93   a ^= a << 16;
  94   a ^= a << 12;
  95   return a;
  96 }
  97
  98 static inline int ipv4_compare(u32 x, u32 y)
  99 {
 100   return (x > y) - (x < y);
 101 }
 102
 103 static inline u32 ipv4_pxlen(u32 a, u32 b)
 104 {
 105   return 31 - u32_log2(a ^ b);
 106 }
 107
 108 static inline byte * ipv4_put_addr(byte *buf, ip_addr a)
 109 {
 110   put_u32(buf, _I(a));
 111   return buf+4;
 112 }
 113
 114 #define IP_PREC_INTERNET_CONTROL 0xc0
 115
 116 #endif