+/* Subnet mask handling */
+
+int maskcmp(const void *va, const void *vb, int masklen) {
+ int i, m, result;
+ const char *a = va;
+ const char *b = vb;
+
+ for(m = masklen, i = 0; m >= 8; m -= 8, i++) {
+ result = a[i] - b[i];
+ if(result)
+ return result;
+ }
+
+ if(m)
+ return (a[i] & (0x100 - (1 << (8 - m)))) -
+ (b[i] & (0x100 - (1 << (8 - m))));
+
+ return 0;
+}
+
+void mask(void *va, int masklen, int len) {
+ int i;
+ char *a = va;
+
+ i = masklen / 8;
+ masklen %= 8;
+
+ if(masklen)
+ a[i++] &= (0x100 - (1 << (8 - masklen)));
+
+ for(; i < len; i++)
+ a[i] = 0;
+}
+
+void maskcpy(void *va, const void *vb, int masklen, int len) {
+ int i, m;
+ char *a = va;
+ const char *b = vb;
+
+ for(m = masklen, i = 0; m >= 8; m -= 8, i++)
+ a[i] = b[i];
+
+ if(m) {
+ a[i] = b[i] & (0x100 - (1 << (8 - m)));
+ i++;
+ }
+
+ for(; i < len; i++)
+ a[i] = 0;
+}
+
+bool maskcheck(const void *va, int masklen, int len) {
+ int i;
+ const char *a = va;
+
+ i = masklen / 8;
+ masklen %= 8;
+
+ if(masklen && a[i++] & (0xff >> masklen))
+ return false;