in-addr-util: introduce in_addr_prefix_nth

1 files changed, 40 insertions, 0 deletions

diff --git a/src/test/test-socket-util.c b/src/test/test-socket-util.c
index d36caaa71e..d63f212c19 100644
--- a/src/test/test-socket-util.c
+++ b/src/test/test-socket-util.c
@@ -173,6 +173,45 @@ static void test_in_addr_prefix_next(void) {
         test_in_addr_prefix_next_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff00", 120, NULL);
 }
 
+static void test_in_addr_prefix_nth_one(unsigned f, const char *before, unsigned pl, uint64_t nth, const char *after) {
+        union in_addr_union ubefore, uafter, t;
+
+        assert_se(in_addr_from_string(f, before, &ubefore) >= 0);
+
+        t = ubefore;
+        assert_se((in_addr_prefix_nth(f, &t, pl, nth) > 0) == !!after);
+
+        if (after) {
+                assert_se(in_addr_from_string(f, after, &uafter) >= 0);
+                assert_se(in_addr_equal(f, &t, &uafter) > 0);
+        }
+}
+
+static void test_in_addr_prefix_nth(void) {
+        log_info("/* %s */", __func__);
+
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 0, "192.168.0.0");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 1, "192.168.1.0");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 24, 4, "192.168.4.0");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.0.0", 25, 1, "192.168.0.128");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.255.0", 25, 1, "192.168.255.128");
+        test_in_addr_prefix_nth_one(AF_INET, "192.168.255.0", 24, 0, "192.168.255.0");
+        test_in_addr_prefix_nth_one(AF_INET, "255.255.255.255", 32, 1, NULL);
+        test_in_addr_prefix_nth_one(AF_INET, "255.255.255.255", 0, 1, NULL);
+
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 8, 1, "4500::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 7, 1, "4600::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 64, 1, "4400:0:0:1::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 64, 2, "4400:0:0:2::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 64, 0xbad, "4400:0:0:0bad::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400:0:0:ffff::", 64, 1, "4400:0:1::");
+        test_in_addr_prefix_nth_one(AF_INET6, "4400::", 56, ((uint64_t)1<<48) -1, "44ff:ffff:ffff:ff00::");
+        test_in_addr_prefix_nth_one(AF_INET6, "0000::", 8, 255, "ff00::");
+        test_in_addr_prefix_nth_one(AF_INET6, "0000::", 8, 256, NULL);
+        test_in_addr_prefix_nth_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 128, 1, NULL);
+        test_in_addr_prefix_nth_one(AF_INET6, "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", 0, 1, NULL);
+}
+
 static void test_in_addr_to_string_one(int f, const char *addr) {
         union in_addr_union ua;
         _cleanup_free_ char *r = NULL;
@@ -673,6 +712,7 @@ int main(int argc, char *argv[]) {
         test_in_addr_is_null();
         test_in_addr_prefix_intersect();
         test_in_addr_prefix_next();
+        test_in_addr_prefix_nth();
         test_in_addr_to_string();
         test_in_addr_ifindex_to_string();
         test_in_addr_ifindex_from_string_auto();