in-addr-util: introduce 'struct in_addr_prefix' and hash ops for it

src/basic/in-addr-util.c

@@ -825,6 +825,35 @@ static int in_addr_data_compare_func(const struct in_addr_data *x, const struct
 
 DEFINE_HASH_OPS(in_addr_data_hash_ops, struct in_addr_data, in_addr_data_hash_func, in_addr_data_compare_func);
 
+static void in_addr_prefix_hash_func(const struct in_addr_prefix *a, struct siphash *state) {
+        assert(a);
+        assert(state);
+
+        siphash24_compress(&a->family, sizeof(a->family), state);
+        siphash24_compress(&a->prefixlen, sizeof(a->prefixlen), state);
+        siphash24_compress(&a->address, FAMILY_ADDRESS_SIZE(a->family), state);
+}
+
+static int in_addr_prefix_compare_func(const struct in_addr_prefix *x, const struct in_addr_prefix *y) {
+        int r;
+
+        assert(x);
+        assert(y);
+
+        r = CMP(x->family, y->family);
+        if (r != 0)
+                return r;
+
+        r = CMP(x->prefixlen, y->prefixlen);
+        if (r != 0)
+                return r;
+
+        return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
+}
+
+DEFINE_HASH_OPS(in_addr_prefix_hash_ops, struct in_addr_prefix, in_addr_prefix_hash_func, in_addr_prefix_compare_func);
+DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(in_addr_prefix_hash_ops_free, struct in_addr_prefix, in_addr_prefix_hash_func, in_addr_prefix_compare_func, free);
+
 void in6_addr_hash_func(const struct in6_addr *addr, struct siphash *state) {
         assert(addr);
         assert(state);

src/basic/in-addr-util.h

@@ -20,6 +20,12 @@ struct in_addr_data {
         union in_addr_union address;
 };
 
+struct in_addr_prefix {
+        int family;
+        uint8_t prefixlen;
+        union in_addr_union address;
+};
+
 bool in4_addr_is_null(const struct in_addr *a);
 static inline bool in4_addr_is_set(const struct in_addr *a) {
         return !in4_addr_is_null(a);
@@ -111,4 +117,6 @@ void in6_addr_hash_func(const struct in6_addr *addr, struct siphash *state);
 int in6_addr_compare_func(const struct in6_addr *a, const struct in6_addr *b);
 
 extern const struct hash_ops in_addr_data_hash_ops;
+extern const struct hash_ops in_addr_prefix_hash_ops;
+extern const struct hash_ops in_addr_prefix_hash_ops_free;
 extern const struct hash_ops in6_addr_hash_ops;