diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/bitops.c | 21 | ||||
| -rw-r--r-- | lib/bitops.h | 2 | ||||
| -rw-r--r-- | lib/ipv4.h | 10 | ||||
| -rw-r--r-- | lib/ipv6.h | 20 |
4 files changed, 53 insertions, 0 deletions
diff --git a/lib/bitops.c b/lib/bitops.c index 6ca05050..88cef78a 100644 --- a/lib/bitops.c +++ b/lib/bitops.c @@ -45,3 +45,24 @@ u32_masklen(u32 x) if (x & 0xaaaaaaaa) l++; return l; } + +/** + * u32_log2 - compute a binary logarithm. + * @v: number + * + * This function computes a integral part of binary logarithm of given + * integer @v and returns it. The computed value is also an index of the + * first non-zero bit position. + */ + +u32 +u32_log2(u32 v) +{ + u32 r, shift; + r = (v > 0xFFFF) << 4; v >>= r; + shift = (v > 0xFF ) << 3; v >>= shift; r |= shift; + shift = (v > 0xF ) << 2; v >>= shift; r |= shift; + shift = (v > 0x3 ) << 1; v >>= shift; r |= shift; + r |= (v >> 1); + return r; +} diff --git a/lib/bitops.h b/lib/bitops.h index 1b6dc68e..bebd830d 100644 --- a/lib/bitops.h +++ b/lib/bitops.h @@ -17,3 +17,5 @@ u32 u32_mkmask(unsigned n); int u32_masklen(u32 x); + +u32 u32_log2(u32 v); @@ -35,6 +35,7 @@ typedef u32 ip_addr; #endif +#define MAX_PREFIX_LENGTH 32 #define BITS_PER_IP_ADDRESS 32 #define STD_ADDRESS_P_LENGTH 15 #define SIZE_OF_IP_HEADER 24 @@ -58,6 +59,9 @@ typedef u32 ip_addr; #define ipa_from_u32(x) _MI(x) #define ipa_to_u32(x) _I(x) #define ipa_compare(x,y) ipv4_compare(_I(x),_I(y)) +/* ipa_pxlen() requires that x != y */ +#define ipa_pxlen(x, y) ipv4_pxlen(_I(x), _I(y)) +#define ipa_getbit(x, y) (_I(x) & (0x80000000 >> (y))) #define ip_skip_header(x, y) ipv4_skip_header(x, y) @@ -78,6 +82,12 @@ static inline int ipv4_compare(u32 x, u32 y) return (x > y) - (x < y); } +static inline u32 ipv4_pxlen(u32 a, u32 b) +{ + return 31 - u32_log2(a ^ b); +} + + #define IP_PREC_INTERNET_CONTROL 0xc0 #endif @@ -12,6 +12,7 @@ #include <sys/types.h> #include <netinet/in.h> #include "lib/string.h" +#include "lib/bitops.h" typedef struct ipv6_addr { u32 addr[4]; @@ -23,6 +24,7 @@ typedef struct ipv6_addr { #define _I2(a) ((a).addr[2]) #define _I3(a) ((a).addr[3]) +#define MAX_PREFIX_LENGTH 128 #define BITS_PER_IP_ADDRESS 128 #define STD_ADDRESS_P_LENGTH 39 #define SIZE_OF_IP_HEADER 40 @@ -57,6 +59,9 @@ typedef struct ipv6_addr { /* ipa_from_u32 and ipa_to_u32 replaced by ipa_build */ #define ipa_build(a,b,c,d) _MI(a,b,c,d) #define ipa_compare(x,y) ipv6_compare(x,y) +/* ipa_pxlen() requires that x != y */ +#define ipa_pxlen(x, y) ipv6_pxlen(x, y) +#define ipa_getbit(x, y) ipv6_getbit(x, y) #define ipa_absolutize(x,y) ipv6_absolutize(x,y) ip_addr ipv6_mkmask(unsigned); @@ -81,6 +86,21 @@ static inline unsigned ipv6_hash(ip_addr *a) return (x ^ (x >> 16) ^ (x >> 8)) & 0xffff; } +static inline u32 ipv6_getbit(ip_addr a, u32 y) +{ + return a.addr[y / 32] & (0x80000000 >> (y % 32)); +} + +static inline u32 ipv6_pxlen(ip_addr a, ip_addr b) +{ + int i = 0; + i+= (a.addr[i] == b.addr[i]); + i+= (a.addr[i] == b.addr[i]); + i+= (a.addr[i] == b.addr[i]); + i+= (a.addr[i] == b.addr[i]); + return 32 * i + 31 - u32_log2(a.addr[i] ^ b.addr[i]); +} + /* * RFC 1883 defines packet precendece, but RFC 2460 replaces it * by generic Traffic Class ID with no defined semantics. Better |