network-list: Cap prefix length based on family

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/libloc/network.h

@@ -103,6 +103,19 @@ static inline int loc_address_family(const struct in6_addr* address) {
 		return AF_INET6;
 }
 
+static inline int loc_address_family_bit_length(const int family) {
+	switch (family) {
+		case AF_INET6:
+			return 128;
+
+		case AF_INET:
+			return 32;
+
+		default:
+			return -1;
+	}
+}
+
 static inline int loc_address_all_zeroes(const struct in6_addr* address) {
 	struct in6_addr all_zeroes = IN6ADDR_ANY_INIT;
 

src/network-list.c

@@ -307,10 +307,11 @@ int loc_network_list_summarize(struct loc_ctx* ctx,
 		return 1;
 	}
 
-	int family = loc_address_family(first);
+	const int family1 = loc_address_family(first);
+	const int family2 = loc_address_family(last);
 
-	// Families must match
-	if (family != loc_address_family(last)) {
+	// Check if address families match
+	if (family1 != family2) {
 		ERROR(ctx, "Address families do not match\n");
 		errno = EINVAL;
 		return 1;
@@ -326,11 +327,20 @@ int loc_network_list_summarize(struct loc_ctx* ctx,
 	struct loc_network* network = NULL;
 	struct in6_addr start = *first;
 
+	const int family_bit_length = loc_address_family_bit_length(family1);
+
 	while (in6_addr_cmp(&start, last) <= 0) {
 		struct in6_addr num;
+		int bits1;
 
 		// Find the number of trailing zeroes of the start address
-		int bits1 = loc_address_count_trailing_zero_bits(&start);
+		if (loc_address_all_zeroes(&start))
+			bits1 = family_bit_length;
+		else {
+			bits1 = loc_address_count_trailing_zero_bits(&start);
+			if (bits1 > family_bit_length)
+				bits1 = family_bit_length;
+		}
 
 		// Subtract the start address from the last address and add one
 		// (i.e. how many addresses are in this network?)