+
+int
+fw3_netmask2bitlen(int family, void *mask)
+{
+ int bits;
+ struct in_addr *v4;
+ struct in6_addr *v6;
+
+ if (family == FW3_FAMILY_V6)
+ for (bits = 0, v6 = mask;
+ bits < 128 && (v6->s6_addr[bits / 8] << (bits % 8)) & 128;
+ bits++);
+ else
+ for (bits = 0, v4 = mask;
+ bits < 32 && (ntohl(v4->s_addr) << bits) & 0x80000000;
+ bits++);
+
+ return bits;
+}
+
+bool
+fw3_bitlen2netmask(int family, int bits, void *mask)
+{
+ int i;
+ struct in_addr *v4;
+ struct in6_addr *v6;
+
+ if (family == FW3_FAMILY_V6)
+ {
+ if (bits < -128 || bits > 128)
+ return false;
+
+ v6 = mask;
+ i = abs(bits);
+
+ memset(v6->s6_addr, 0xff, i / 8);
+ memset(v6->s6_addr + (i / 8) + 1, 0, (128 - i) / 8);
+ v6->s6_addr[i / 8] = 0xff << (8 - (i & 7));
+
+ if (bits < 0)
+ for (i = 0; i < 16; i++)
+ v6->s6_addr[i] = ~v6->s6_addr[i];
+ }
+ else
+ {
+ if (bits < -32 || bits > 32)
+ return false;
+
+ v4 = mask;
+ v4->s_addr = htonl(~((1 << (32 - abs(bits))) - 1));
+
+ if (bits < 0)
+ v4->s_addr = ~v4->s_addr;
+ }
+
+ return true;
+}