diff options
| -rw-r--r-- | lib/prefix.c | 128 |
1 files changed, 19 insertions, 109 deletions
diff --git a/lib/prefix.c b/lib/prefix.c index 60e573a6..a3b1adf8 100644 --- a/lib/prefix.c +++ b/lib/prefix.c @@ -31,79 +31,6 @@ /* Maskbit. */ static const u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff}; -static const u_int32_t maskbytes_big_endian[] = -{ - 0x00000000, /* /0 0.0.0.0 */ - 0x80000000, /* /1 128.0.0.0 */ - 0xc0000000, /* /2 192.0.0.0 */ - 0xe0000000, /* /3 224.0.0.0 */ - 0xf0000000, /* /4 240.0.0.0 */ - 0xf8000000, /* /5 248.0.0.0 */ - 0xfc000000, /* /6 252.0.0.0 */ - 0xfe000000, /* /7 254.0.0.0 */ - 0xff000000, /* /8 255.0.0.0 */ - 0xff800000, /* /9 255.128.0.0 */ - 0xffc00000, /* /10 255.192.0.0 */ - 0xffe00000, /* /11 255.224.0.0 */ - 0xfff00000, /* /12 255.240.0.0 */ - 0xfff80000, /* /13 255.248.0.0 */ - 0xfffc0000, /* /14 255.252.0.0 */ - 0xfffe0000, /* /15 255.254.0.0 */ - 0xffff0000, /* /16 255.255.0.0 */ - 0xffff8000, /* /17 255.255.128.0 */ - 0xffffc000, /* /18 255.255.192.0 */ - 0xffffe000, /* /19 255.255.224.0 */ - 0xfffff000, /* /20 255.255.240.0 */ - 0xfffff800, /* /21 255.255.248.0 */ - 0xfffffc00, /* /22 255.255.252.0 */ - 0xfffffe00, /* /23 255.255.254.0 */ - 0xffffff00, /* /24 255.255.255.0 */ - 0xffffff80, /* /25 255.255.255.128 */ - 0xffffffc0, /* /26 255.255.255.192 */ - 0xffffffe0, /* /27 255.255.255.224 */ - 0xfffffff0, /* /28 255.255.255.240 */ - 0xfffffff8, /* /29 255.255.255.248 */ - 0xfffffffc, /* /30 255.255.255.252 */ - 0xfffffffe, /* /31 255.255.255.254 */ - 0xffffffff /* /32 255.255.255.255 */ -}; - -static const u_int32_t maskbytes_little_endian[] = -{ - 0x00000000, /* /0 0.0.0.0 */ - 0x00000080, /* /1 128.0.0.0 */ - 0x000000c0, /* /2 192.0.0.0 */ - 0x000000e0, /* /3 224.0.0.0 */ - 0x000000f0, /* /4 240.0.0.0 */ - 0x000000f8, /* /5 248.0.0.0 */ - 0x000000fc, /* /6 252.0.0.0 */ - 0x000000fe, /* /7 254.0.0.0 */ - 0x000000ff, /* /8 255.0.0.0 */ - 0x000080ff, /* /9 255.128.0.0 */ - 0x0000c0ff, /* /10 255.192.0.0 */ - 0x0000e0ff, /* /11 255.224.0.0 */ - 0x0000f0ff, /* /12 255.240.0.0 */ - 0x0000f8ff, /* /13 255.248.0.0 */ - 0x0000fcff, /* /14 255.252.0.0 */ - 0x0000feff, /* /15 255.254.0.0 */ - 0x0000ffff, /* /16 255.255.0.0 */ - 0x0080ffff, /* /17 255.255.128.0 */ - 0x00c0ffff, /* /18 255.255.192.0 */ - 0x00e0ffff, /* /19 255.255.224.0 */ - 0x00f0ffff, /* /20 255.255.240.0 */ - 0x00f8ffff, /* /21 255.255.248.0 */ - 0x00fcffff, /* /22 255.255.252.0 */ - 0x00feffff, /* /23 255.255.254.0 */ - 0x00ffffff, /* /24 255.255.255.0 */ - 0x80ffffff, /* /25 255.255.255.128 */ - 0xc0ffffff, /* /26 255.255.255.192 */ - 0xe0ffffff, /* /27 255.255.255.224 */ - 0xf0ffffff, /* /28 255.255.255.240 */ - 0xf8ffffff, /* /29 255.255.255.248 */ - 0xfcffffff, /* /30 255.255.255.252 */ - 0xfeffffff, /* /31 255.255.255.254 */ - 0xffffffff /* /32 255.255.255.255 */ -}; static const struct in6_addr maskbytes6[] = { @@ -527,11 +454,15 @@ void masklen2ip (const int masklen, struct in_addr *netmask) { assert (masklen >= 0 && masklen <= IPV4_MAX_BITLEN); -#if (BYTE_ORDER == LITTLE_ENDIAN) - netmask->s_addr = maskbytes_little_endian[masklen]; -#elif (BYTE_ORDER == BIG_ENDIAN) - netmask->s_addr = maskbytes_big_endian[masklen]; -#endif + + /* left shift is only defined for less than the size of the type. + * we unconditionally use long long in case the target platform + * has defined behaviour for << 32 (or has a 64-bit left shift) */ + + if (sizeof(unsigned long long) > 4) + netmask->s_addr = htonl(0xffffffffULL << (32 - masklen)); + else + netmask->s_addr = htonl(masklen ? 0xffffffffU << (32 - masklen) : 0); } /* Convert IP address's netmask into integer. We assume netmask is @@ -539,43 +470,22 @@ masklen2ip (const int masklen, struct in_addr *netmask) u_char ip_masklen (struct in_addr netmask) { - u_char len; - u_char *pnt; - u_char *end; - u_char val; - - len = 0; - pnt = (u_char *) &netmask; - end = pnt + 4; - - while ((pnt < end) && (*pnt == 0xff)) - { - len+= 8; - pnt++; - } - - if (pnt < end) - { - val = *pnt; - while (val) - { - len++; - val <<= 1; - } - } - return len; + uint32_t tmp = ~ntohl(netmask.s_addr); + if (tmp) + /* clz: count leading zeroes. sadly, the behaviour of this builtin + * is undefined for a 0 argument, even though most CPUs give 32 */ + return __builtin_clz(tmp); + else + return 32; } /* Apply mask to IPv4 prefix (network byte order). */ void apply_mask_ipv4 (struct prefix_ipv4 *p) { - assert (p->prefixlen >= 0 && p->prefixlen <= IPV4_MAX_BITLEN); -#if (BYTE_ORDER == LITTLE_ENDIAN) - p->prefix.s_addr &= maskbytes_little_endian[p->prefixlen]; -#elif (BYTE_ORDER == BIG_ENDIAN) - p->prefix.s_addr &= maskbytes_big_endian[p->prefixlen]; -#endif + struct in_addr mask; + masklen2ip(p->prefixlen, &mask); + p->prefix.s_addr &= mask.s_addr; } /* If prefix is 0.0.0.0/0 then return 1 else return 0. */ |