dhclient: use fqdn.fqdn for server DDNS updates

dhclient only supports fqdn.fqdn for server DDNS updates with
DHCPv6.  And even though the underlying DHCP options that fqdn.fqdn
controls allow non-qualified hostnames on the wire, dhclient does
not.  So we must require a fully-qualified name for DHCPv6.

Second, while no-client-updates seems like it should be "off", doing
that apparently makes dhclient set the "O" flag to 1 which appears to
be a bug, and results in the server not doing the DDNS update.  So
we must stop setting that option too.

Found by: Alexander Groß

src/dhcp-manager/nm-dhcp-dhclient-utils.c

@@ -39,8 +39,8 @@
 #define HOSTNAME4_TAG    "send host-name"
 #define HOSTNAME4_FORMAT HOSTNAME4_TAG " \"%s\"; # added by NetworkManager"
 
-#define HOSTNAME6_TAG    "send fqdn.fqdn"
+#define FQDN_TAG    "send fqdn.fqdn"
-#define HOSTNAME6_FORMAT HOSTNAME6_TAG " \"%s\"; # added by NetworkManager"
+#define FQDN_FORMAT FQDN_TAG " \"%s\"; # added by NetworkManager"
 
 #define ALSOREQ_TAG "also request "
 
@@ -57,7 +57,7 @@ add_also_request (GPtrArray *array, const char *item)
 }
 
 static void
-add_hostname (GString *str, const char *format, const char *hostname)
+add_hostname4 (GString *str, const char *format, const char *hostname)
 {
 	char *plain_hostname, *dot;
 
@@ -109,7 +109,7 @@ add_ip4_config (GString *str, GBytes *client_id, const char *hostname)
 		g_string_append (str, "; # added by NetworkManager\n");
 	}
 
-	add_hostname (str, HOSTNAME4_FORMAT "\n", hostname);
+	add_hostname4 (str, HOSTNAME4_FORMAT "\n", hostname);
 
 	g_string_append_c (str, '\n');
 
@@ -125,13 +125,18 @@ add_ip4_config (GString *str, GBytes *client_id, const char *hostname)
 }
 
 static void
-add_ip6_config (GString *str, const char *hostname)
+add_hostname6 (GString *str, const char *hostname)
 {
-	add_hostname (str, HOSTNAME6_FORMAT "\n", hostname);
+	/* dhclient only supports the fqdn.fqdn for DHCPv6 and requires a fully-
+	 * qualified name for this option, so we must require one here too.
+	 */
+	if (hostname && strchr (hostname, '.')) {
+		g_string_append_printf (str, FQDN_FORMAT "\n", hostname);
 		g_string_append (str,
 		                 "send fqdn.encoded on;\n"
-	                 "send fqdn.no-client-update on;\n"
 		                 "send fqdn.server-update on;\n");
+		g_string_append_c (str, '\n');
+	}
 }
 
 static GBytes *
@@ -232,7 +237,7 @@ nm_dhcp_dhclient_create_config (const char *interface,
 			if (hostname) {
 				if (strncmp (p, HOSTNAME4_TAG, strlen (HOSTNAME4_TAG)) == 0)
 					continue;
-				if (strncmp (p, HOSTNAME6_TAG, strlen (HOSTNAME6_TAG)) == 0)
+				if (strncmp (p, FQDN_TAG, strlen (FQDN_TAG)) == 0)
 					continue;
 			}
 
@@ -290,7 +295,7 @@ nm_dhcp_dhclient_create_config (const char *interface,
 		g_string_append_c (new_contents, '\n');
 
 	if (is_ip6) {
-		add_ip6_config (new_contents, hostname);
+		add_hostname6 (new_contents, hostname);
 		add_also_request (alsoreq, "dhcp6.name-servers");
 		add_also_request (alsoreq, "dhcp6.domain-search");
 		add_also_request (alsoreq, "dhcp6.client-id");

src/dhcp-manager/tests/test-dhcp-dhclient.c

@@ -39,6 +39,7 @@
 static void
 test_config (const char *orig,
              const char *expected,
+             gboolean ipv6,
              const char *hostname,
              const char *dhcp_client_id,
              GBytes *expected_new_client_id,
@@ -55,7 +56,7 @@ test_config (const char *orig,
 	}
 
 	new = nm_dhcp_dhclient_create_config (iface,
-	                                      FALSE,
+	                                      ipv6,
 	                                      client_id,
 	                                      anycast_addr,
 	                                      hostname,
@@ -103,7 +104,7 @@ static const char *orig_missing_expected = \
 static void
 test_orig_missing (void)
 {
-	test_config (NULL, orig_missing_expected, NULL, NULL, NULL, "eth0", NULL);
+	test_config (NULL, orig_missing_expected, FALSE, NULL, NULL, NULL, "eth0", NULL);
 }
 
 /*******************************************/
@@ -132,7 +133,7 @@ static void
 test_override_client_id (void)
 {
 	test_config (override_client_id_orig, override_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             "11:22:33:44:55:66",
 	             NULL,
 	             "eth0",
@@ -161,7 +162,7 @@ static void
 test_quote_client_id (void)
 {
 	test_config (NULL, quote_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             "1234",
 	             NULL,
 	             "eth0",
@@ -190,7 +191,7 @@ static void
 test_ascii_client_id (void)
 {
 	test_config (NULL, ascii_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             "qb:cd:ef:12:34:56",
 	             NULL,
 	             "eth0",
@@ -219,7 +220,7 @@ static void
 test_hex_single_client_id (void)
 {
 	test_config (NULL, hex_single_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             "ab:cd:e:12:34:56",
 	             NULL,
 	             "eth0",
@@ -256,7 +257,7 @@ test_existing_hex_client_id (void)
 
 	new_client_id = g_bytes_new (bytes, sizeof (bytes));
 	test_config (existing_hex_client_id_orig, existing_hex_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             NULL,
 	             new_client_id,
 	             "eth0",
@@ -296,7 +297,7 @@ test_existing_ascii_client_id (void)
 	memcpy (buf + 1, EACID, STRLEN (EACID));
 	new_client_id = g_bytes_new (buf, sizeof (buf));
 	test_config (existing_ascii_client_id_orig, existing_ascii_client_id_expected,
-	             NULL,
+	             FALSE, NULL,
 	             NULL,
 	             new_client_id,
 	             "eth0",
@@ -329,7 +330,58 @@ static void
 test_override_hostname (void)
 {
 	test_config (override_hostname_orig, override_hostname_expected,
-	             "blahblah",
+	             FALSE, "blahblah",
+	             NULL,
+	             NULL,
+	             "eth0",
+	             NULL);
+}
+
+/*******************************************/
+
+static const char *override_hostname6_orig = \
+	"send fqdn.fqdn \"foobar\";\n";
+
+static const char *override_hostname6_expected = \
+	"# Created by NetworkManager\n"
+	"# Merged from /path/to/dhclient.conf\n"
+	"\n"
+	"send fqdn.fqdn \"blahblah.local\"; # added by NetworkManager\n"
+	"send fqdn.encoded on;\n"
+	"send fqdn.server-update on;\n"
+	"\n"
+	"also request dhcp6.name-servers;\n"
+	"also request dhcp6.domain-search;\n"
+	"also request dhcp6.client-id;\n"
+	"\n";
+
+static void
+test_override_hostname6 (void)
+{
+	test_config (override_hostname6_orig, override_hostname6_expected,
+	             TRUE, "blahblah.local",
+	             NULL,
+	             NULL,
+	             "eth0",
+	             NULL);
+}
+
+/*******************************************/
+
+static const char *nonfqdn_hostname6_expected = \
+	"# Created by NetworkManager\n"
+	"\n"
+	"also request dhcp6.name-servers;\n"
+	"also request dhcp6.domain-search;\n"
+	"also request dhcp6.client-id;\n"
+	"\n";
+
+static void
+test_nonfqdn_hostname6 (void)
+{
+	/* Non-FQDN hostname can't be used with dhclient */
+	test_config (NULL, nonfqdn_hostname6_expected,
+	             TRUE, "blahblah",
 	             NULL,
 	             NULL,
 	             "eth0",
@@ -364,7 +416,7 @@ static void
 test_existing_alsoreq (void)
 {
 	test_config (existing_alsoreq_orig, existing_alsoreq_expected,
-	             NULL,
+	             FALSE, NULL,
 	             NULL,
 	             NULL,
 	             "eth0",
@@ -403,7 +455,7 @@ static void
 test_existing_multiline_alsoreq (void)
 {
 	test_config (existing_multiline_alsoreq_orig, existing_multiline_alsoreq_expected,
-	             NULL,
+	             FALSE, NULL,
 	             NULL,
 	             NULL,
 	             "eth0",
@@ -721,6 +773,8 @@ main (int argc, char **argv)
 	g_test_add_func ("/dhcp/dhclient/existing-hex-client-id", test_existing_hex_client_id);
 	g_test_add_func ("/dhcp/dhclient/existing-ascii-client-id", test_existing_ascii_client_id);
 	g_test_add_func ("/dhcp/dhclient/override_hostname", test_override_hostname);
+	g_test_add_func ("/dhcp/dhclient/override_hostname6", test_override_hostname6);
+	g_test_add_func ("/dhcp/dhclient/nonfqdn_hostname6", test_nonfqdn_hostname6);
 	g_test_add_func ("/dhcp/dhclient/existing_alsoreq", test_existing_alsoreq);
 	g_test_add_func ("/dhcp/dhclient/existing_multiline_alsoreq", test_existing_multiline_alsoreq);
 	g_test_add_func ("/dhcp/dhclient/duids", test_duids);