lib/ipv6.h

   1
   2 /*
   3  *      BIRD -- IP Addresses et Cetera for IPv6
   4  *
   5  *      (c) 1999--2000 Martin Mares <mj@ucw.cz>
   6  *
   7  *      Can be freely distributed and used under the terms of the GNU GPL.
   8  */
   9
  10 #ifndef _BIRD_IPV6_H_
  11 #define _BIRD_IPV6_H_
  12
  13 #include <sys/types.h>
  14 #include <netinet/in.h>
  15 #include "lib/string.h"
  16 #include "lib/bitops.h"
  17 #include "lib/unaligned.h"
  18
  19 typedef struct ipv6_addr {
  20   u32 addr[4];
  21 } ip_addr;
  22
  23 #define _MI(a,b,c,d) ((struct ipv6_addr) {{ a, b, c, d }})
  24 #define _I0(a) ((a).addr[0])
  25 #define _I1(a) ((a).addr[1])
  26 #define _I2(a) ((a).addr[2])
  27 #define _I3(a) ((a).addr[3])
  28
  29 #define MAX_PREFIX_LENGTH 128
  30 #define BITS_PER_IP_ADDRESS 128
  31 #define STD_ADDRESS_P_LENGTH 39
  32 #define SIZE_OF_IP_HEADER 40
  33
  34 #define IPA_NONE _MI(0,0,0,0)
  35
  36 #define ipa_equal(x,y)  ({ ip_addr _a=(x), _b=(y); \
  37                            _I0(_a) == _I0(_b) && \
  38                            _I1(_a) == _I1(_b) && \
  39                            _I2(_a) == _I2(_b) && \
  40                            _I3(_a) == _I3(_b); })
  41 #define ipa_nonzero(x) ({ ip_addr _a=(x); (_I0(_a) || _I1(_a) || _I2(_a) || _I3(_a)); })
  42 #define ipa_and(x,y) ({ ip_addr _a=(x), _b=(y); \
  43                      _MI(_I0(_a) & _I0(_b), \
  44                          _I1(_a) & _I1(_b), \
  45                          _I2(_a) & _I2(_b), \
  46                          _I3(_a) & _I3(_b)); })
  47 #define ipa_or(x,y)  ({ ip_addr _a=(x), _b=(y); \
  48                      _MI(_I0(_a) | _I0(_b), \
  49                          _I1(_a) | _I1(_b), \
  50                          _I2(_a) | _I2(_b), \
  51                          _I3(_a) | _I3(_b)); })
  52 #define ipa_xor(x,y) ({ ip_addr _a=(x), _b=(y); \
  53                      _MI(_I0(_a) ^ _I0(_b), \
  54                          _I1(_a) ^ _I1(_b), \
  55                          _I2(_a) ^ _I2(_b), \
  56                          _I3(_a) ^ _I3(_b)); })
  57 #define ipa_not(x) ({ ip_addr _a=(x); _MI(~_I0(_a),~_I1(_a),~_I2(_a),~_I3(_a)); })
  58 #define ipa_mkmask(x) ipv6_mkmask(x)
  59 #define ipa_mklen(x) ipv6_mklen(&(x))
  60 #define ipa_hash(x) ipv6_hash(&(x))
  61 #define ipa_hton(x) ipv6_hton(&(x))
  62 #define ipa_ntoh(x) ipv6_ntoh(&(x))
  63 #define ipa_classify(x) ipv6_classify(&(x))
  64 #define ipa_has_link_scope(x) ipv6_has_link_scope(&(x))
  65 #define ipa_opposite_m1(x) ({ ip_addr _a=(x); _MI(_I0(_a),_I1(_a),_I2(_a),_I3(_a) ^ 1); })
  66 #define ipa_opposite_m2(x) ({ ip_addr _a=(x); _MI(_I0(_a),_I1(_a),_I2(_a),_I3(_a) ^ 3); })
  67 /* ipa_class_mask don't make sense with IPv6 */
  68 /* ipa_from_u32 and ipa_to_u32 replaced by ipa_build */
  69 #define ipa_build(a,b,c,d) _MI(a,b,c,d)
  70 #define ipa_compare(x,y) ipv6_compare(x,y)
  71 /* ipa_pxlen() requires that x != y */
  72 #define ipa_pxlen(x, y) ipv6_pxlen(x, y)
  73 #define ipa_getbit(x, y) ipv6_getbit(x, y)
  74 #define ipa_put_addr(x, y) ipv6_put_addr(x, y)
  75 #define ipa_absolutize(x,y) ipv6_absolutize(x,y)
  76
  77 /* In IPv6, SOCK_RAW does not return packet header */
  78 #define ip_skip_header(x, y) x
  79
  80 ip_addr ipv6_mkmask(unsigned);
  81 unsigned ipv6_mklen(ip_addr *);
  82 int ipv6_classify(ip_addr *);
  83 void ipv6_hton(ip_addr *);
  84 void ipv6_ntoh(ip_addr *);
  85 int ipv6_compare(ip_addr, ip_addr);
  86 int ipv4_pton_u32(char *, u32 *);
  87 void ipv6_absolutize(ip_addr *, ip_addr *);
  88
  89 static inline int ipv6_has_link_scope(ip_addr *a)
  90 {
  91   return ((a->addr[0] & 0xffc00000) == 0xfe800000);
  92 }
  93
  94 /*
  95  *  This hash function looks well, but once IPv6 enters
  96  *  mainstream use, we need to check that it has good
  97  *  distribution properties on real routing tables.
  98  */
  99
 100 static inline unsigned ipv6_hash(ip_addr *a)
 101 {
 102   /* Returns a 16-bit hash key */
 103   u32 x = _I0(*a) ^ _I1(*a) ^ _I2(*a) ^ _I3(*a);
 104   return (x ^ (x >> 16) ^ (x >> 8)) & 0xffff;
 105 }
 106
 107 static inline u32 ipv6_getbit(ip_addr a, u32 y)
 108 {
 109   return a.addr[y / 32] & (0x80000000 >> (y % 32));
 110 }
 111
 112 static inline u32 ipv6_pxlen(ip_addr a, ip_addr b)
 113 {
 114   int i = 0;
 115   i+= (a.addr[i] == b.addr[i]);
 116   i+= (a.addr[i] == b.addr[i]);
 117   i+= (a.addr[i] == b.addr[i]);
 118   i+= (a.addr[i] == b.addr[i]);
 119   return 32 * i + 31 - u32_log2(a.addr[i] ^ b.addr[i]);
 120 }
 121
 122 static inline byte * ipv6_put_addr(byte *buf, ip_addr a)
 123 {
 124   put_u32(buf+0,  _I0(a));
 125   put_u32(buf+4,  _I1(a));
 126   put_u32(buf+8,  _I2(a));
 127   put_u32(buf+12, _I3(a));
 128   return buf+16;
 129 }
 130
 131 #define IP_PREC_INTERNET_CONTROL 0xc0
 132
 133 #endif