core: honor the ipv4.dhcp-reject-servers property

src/devices/nm-device.c

@@ -8876,6 +8876,7 @@ dhcp4_start (NMDevice *self)
 	NMSettingConnection *s_con;
 	GError *error = NULL;
 	const NMPlatformLink *pllink;
+	const char *const *reject_servers;
 
 	connection = nm_device_get_applied_connection (self);
 	g_return_val_if_fail (connection, FALSE);
@@ -8898,6 +8899,7 @@ dhcp4_start (NMDevice *self)
 	client_id = dhcp4_get_client_id (self, connection, hwaddr);
 	vendor_class_identifier
 	    = dhcp4_get_vendor_class_identifier (self, NM_SETTING_IP4_CONFIG (s_ip4));
+	reject_servers = nm_setting_ip_config_get_dhcp_reject_servers (s_ip4, NULL);
 
 	g_warn_if_fail (priv->dhcp_data_4.client == NULL);
 	priv->dhcp_data_4.client = nm_dhcp_manager_start_ip4 (nm_dhcp_manager_get (),
@@ -8919,6 +8921,7 @@ dhcp4_start (NMDevice *self)
 	                                                      priv->dhcp_anycast_address,
 	                                                      NULL,
 	                                                      vendor_class_identifier,
+	                                                      reject_servers,
 	                                                      &error);
 	if (!priv->dhcp_data_4.client) {
 		_LOGW (LOGD_DHCP4, "failure to start DHCP: %s", error->message);

src/dhcp/nm-dhcp-client.c

@@ -52,6 +52,7 @@ NM_GOBJECT_PROPERTIES_DEFINE (NMDhcpClient,
 	PROP_HOSTNAME_FLAGS,
 	PROP_MUD_URL,
 	PROP_VENDOR_CLASS_IDENTIFIER,
+	PROP_REJECT_SERVERS,
 );
 
 typedef struct _NMDhcpClientPrivate {
@@ -62,6 +63,7 @@ typedef struct _NMDhcpClientPrivate {
 	char *       uuid;
 	GBytes *     client_id;
 	char *       hostname;
+	const char **reject_servers;
 	char *       mud_url;
 	GBytes *     vendor_class_identifier;
 	pid_t        pid;
@@ -332,6 +334,14 @@ nm_dhcp_client_get_vendor_class_identifier (NMDhcpClient *self)
 	return NM_DHCP_CLIENT_GET_PRIVATE (self)->vendor_class_identifier;
 }
 
+const char *const *
+nm_dhcp_client_get_reject_servers (NMDhcpClient *self)
+{
+	g_return_val_if_fail (NM_IS_DHCP_CLIENT (self), NULL);
+
+	return (const char *const *) NM_DHCP_CLIENT_GET_PRIVATE (self)->reject_servers;
+}
+
 /*****************************************************************************/
 
 static const char *state_table[NM_DHCP_STATE_MAX + 1] = {
@@ -954,6 +964,38 @@ nm_dhcp_client_handle_event (gpointer unused,
 	return TRUE;
 }
 
+gboolean
+nm_dhcp_client_server_id_is_rejected (NMDhcpClient *self, gconstpointer addr)
+{
+	NMDhcpClientPrivate *priv = NM_DHCP_CLIENT_GET_PRIVATE (self);
+	in_addr_t addr4 = *(in_addr_t *) addr;
+	guint i;
+
+	/* IPv6 not implemented yet */
+	nm_assert (priv->addr_family == AF_INET);
+
+	if (!priv->reject_servers || !priv->reject_servers[0])
+		return FALSE;
+
+	for (i = 0; priv->reject_servers[i]; i++) {
+		in_addr_t r_addr;
+		in_addr_t mask;
+		int r_prefix;
+
+		if (!nm_utils_parse_inaddr_prefix_bin (AF_INET,
+		                                       priv->reject_servers[i],
+		                                       NULL,
+		                                       &r_addr,
+		                                       &r_prefix))
+			nm_assert_not_reached ();
+		mask = _nm_utils_ip4_prefix_to_netmask (r_prefix < 0 ? 32 : r_prefix);
+		if ((addr4 & mask) == (r_addr & mask))
+			return TRUE;
+	}
+
+	return FALSE;
+}
+
 /*****************************************************************************/
 
 static void
@@ -1090,6 +1132,10 @@ set_property (GObject *object, guint prop_id,
 		/* construct-only */
 		priv->vendor_class_identifier = g_value_dup_boxed (value);
 		break;
+	case PROP_REJECT_SERVERS:
+		/* construct-only */
+		priv->reject_servers = nm_utils_strv_dup_packed (g_value_get_boxed (value), -1);
+		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 		break;
@@ -1131,6 +1177,7 @@ dispose (GObject *object)
 	nm_clear_g_free (&priv->hostname);
 	nm_clear_g_free (&priv->uuid);
 	nm_clear_g_free (&priv->mud_url);
+	nm_clear_g_free (&priv->reject_servers);
 	nm_clear_pointer (&priv->client_id, g_bytes_unref);
 	nm_clear_pointer (&priv->hwaddr, g_bytes_unref);
 	nm_clear_pointer (&priv->bcast_hwaddr, g_bytes_unref);
@@ -1258,6 +1305,12 @@ nm_dhcp_client_class_init (NMDhcpClientClass *client_class)
 	                        G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
 	                        G_PARAM_STATIC_STRINGS);
 
+	obj_properties[PROP_REJECT_SERVERS] =
+	    g_param_spec_boxed (NM_DHCP_CLIENT_REJECT_SERVERS, "", "",
+	                        G_TYPE_STRV,
+	                        G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY |
+	                        G_PARAM_STATIC_STRINGS);
+
 	g_object_class_install_properties (object_class, _PROPERTY_ENUMS_LAST, obj_properties);
 
 	signals[SIGNAL_STATE_CHANGED] =

src/dhcp/nm-dhcp-client.h

@@ -39,6 +39,7 @@
 #define NM_DHCP_CLIENT_IAID_EXPLICIT             "iaid-explicit"
 #define NM_DHCP_CLIENT_HOSTNAME_FLAGS            "hostname-flags"
 #define NM_DHCP_CLIENT_VENDOR_CLASS_IDENTIFIER   "vendor-class-identifier"
+#define NM_DHCP_CLIENT_REJECT_SERVERS            "reject-servers"
 
 #define NM_DHCP_CLIENT_SIGNAL_STATE_CHANGED "state-changed"
 #define NM_DHCP_CLIENT_SIGNAL_PREFIX_DELEGATED "prefix-delegated"
@@ -144,9 +145,11 @@ GBytes *nm_dhcp_client_get_client_id (NMDhcpClient *self);
 
 const char *nm_dhcp_client_get_hostname (NMDhcpClient *self);
 const char *nm_dhcp_client_get_mud_url (NMDhcpClient *self);
+const char *const *nm_dhcp_client_get_reject_servers (NMDhcpClient *self);
 
 NMDhcpHostnameFlags nm_dhcp_client_get_hostname_flags (NMDhcpClient *self);
 
+
 gboolean nm_dhcp_client_get_info_only (NMDhcpClient *self);
 
 gboolean nm_dhcp_client_get_use_fqdn (NMDhcpClient *self);
@@ -208,6 +211,8 @@ void nm_dhcp_client_set_client_id_bin (NMDhcpClient *self,
 void nm_dhcp_client_emit_ipv6_prefix_delegated (NMDhcpClient *self,
                                                 const NMPlatformIP6Address *prefix);
 
+gboolean nm_dhcp_client_server_id_is_rejected (NMDhcpClient *self, gconstpointer addr);
+
 /*****************************************************************************
  * Client data
  *****************************************************************************/

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

@@ -307,6 +307,7 @@ nm_dhcp_dhclient_create_config (const char *interface,
                                 gboolean use_fqdn,
                                 NMDhcpHostnameFlags hostname_flags,
                                 const char *mud_url,
+                                const char *const *reject_servers,
                                 const char *orig_path,
                                 const char *orig_contents,
                                 GBytes **out_new_client_id)
@@ -319,6 +320,7 @@ nm_dhcp_dhclient_create_config (const char *interface,
 
 	g_return_val_if_fail (!anycast_addr || nm_utils_hwaddr_valid (anycast_addr, ETH_ALEN), NULL);
 	g_return_val_if_fail (NM_IN_SET (addr_family, AF_INET, AF_INET6), NULL);
+	g_return_val_if_fail (!reject_servers || addr_family == AF_INET, NULL);
 	nm_assert (!out_new_client_id || !*out_new_client_id);
 
 	new_contents = g_string_new (_("# Created by NetworkManager\n"));
@@ -473,6 +475,18 @@ nm_dhcp_dhclient_create_config (const char *interface,
 	}
 
 	add_mud_url_config (new_contents, mud_url, addr_family);
+
+	if (   reject_servers
+	    && reject_servers[0]) {
+		g_string_append (new_contents, "reject ");
+		for (i = 0; reject_servers[i]; i++) {
+			if (i != 0)
+				g_string_append (new_contents, ", ");
+			g_string_append (new_contents, reject_servers[i]);
+		}
+		g_string_append (new_contents, ";\n");
+	}
+
 	if (addr_family == AF_INET) {
 		add_ip4_config (new_contents, client_id, hostname, use_fqdn, hostname_flags);
 		add_request (reqs, "rfc3442-classless-static-routes");

src/dhcp/nm-dhcp-dhclient-utils.h

@@ -18,6 +18,7 @@ char *nm_dhcp_dhclient_create_config (const char *interface,
                                       gboolean use_fqdn,
                                       NMDhcpHostnameFlags hostname_flags,
                                       const char *mud_url,
+                                      const char *const *reject_servers,
                                       const char *orig_path,
                                       const char *orig_contents,
                                       GBytes **out_new_client_id);

src/dhcp/nm-dhcp-dhclient.c

@@ -148,6 +148,7 @@ merge_dhclient_config (NMDhcpDhclient *self,
                        gboolean use_fqdn,
                        NMDhcpHostnameFlags hostname_flags,
                        const char *mud_url,
+                       const char *const *reject_servers,
                        const char *orig_path,
                        GBytes **out_new_client_id,
                        GError **error)
@@ -178,6 +179,7 @@ merge_dhclient_config (NMDhcpDhclient *self,
 	                                      use_fqdn,
 	                                      hostname_flags,
 	                                      mud_url,
+	                                      reject_servers,
 	                                      orig_path,
 	                                      orig,
 	                                      out_new_client_id);
@@ -271,6 +273,7 @@ create_dhclient_config (NMDhcpDhclient *self,
                         gboolean use_fqdn,
                         NMDhcpHostnameFlags hostname_flags,
                         const char *mud_url,
+                        const char *const *reject_servers,
                         GBytes **out_new_client_id)
 {
 	gs_free char *orig = NULL;
@@ -300,6 +303,7 @@ create_dhclient_config (NMDhcpDhclient *self,
 	                            use_fqdn,
 	                            hostname_flags,
 	                            mud_url,
+	                            reject_servers,
 	                            orig,
 	                            out_new_client_id,
 	                            &error)) {
@@ -501,6 +505,7 @@ ip4_start (NMDhcpClient *client,
 	                                          nm_dhcp_client_get_use_fqdn (client),
 	                                          nm_dhcp_client_get_hostname_flags (client),
 	                                          nm_dhcp_client_get_mud_url (client),
+	                                          nm_dhcp_client_get_reject_servers (client),
 	                                          &new_client_id);
 	if (!priv->conf_file) {
 		nm_utils_error_set_literal (error,
@@ -546,6 +551,7 @@ ip6_start (NMDhcpClient *client,
 	                                          TRUE,
 	                                          nm_dhcp_client_get_hostname_flags (client),
 	                                          nm_dhcp_client_get_mud_url (client),
+	                                          NULL,
 	                                          NULL);
 	if (!priv->conf_file) {
 		nm_utils_error_set_literal (error,

src/dhcp/nm-dhcp-manager.c

@@ -226,6 +226,7 @@ client_start (NMDhcpManager *self,
               const char *last_ip4_address,
               guint needed_prefixes,
               GBytes *vendor_class_identifier,
+              const char *const *reject_servers,
               GError **error)
 {
 	NMDhcpManagerPrivate *priv;
@@ -318,6 +319,7 @@ client_start (NMDhcpManager *self,
 	                       NM_DHCP_CLIENT_TIMEOUT, (guint) timeout,
 	                       NM_DHCP_CLIENT_HOSTNAME_FLAGS, (guint) hostname_flags,
 	                       NM_DHCP_CLIENT_VENDOR_CLASS_IDENTIFIER, vendor_class_identifier,
+	                       NM_DHCP_CLIENT_REJECT_SERVERS, reject_servers,
 	                       NM_DHCP_CLIENT_FLAGS, (guint) (0
 	                           | (hostname_use_fqdn ? NM_DHCP_CLIENT_FLAGS_USE_FQDN  : 0)
 	                           | (info_only         ? NM_DHCP_CLIENT_FLAGS_INFO_ONLY : 0)
@@ -399,6 +401,7 @@ nm_dhcp_manager_start_ip4 (NMDhcpManager *self,
                            const char *dhcp_anycast_addr,
                            const char *last_ip_address,
                            GBytes *vendor_class_identifier,
+                           const char *const *reject_servers,
                            GError **error)
 {
 	NMDhcpManagerPrivate *priv;
@@ -459,6 +462,7 @@ nm_dhcp_manager_start_ip4 (NMDhcpManager *self,
 	                     last_ip_address,
 	                     0,
 	                     vendor_class_identifier,
+	                     reject_servers,
 	                     error);
 }
 
@@ -523,6 +527,7 @@ nm_dhcp_manager_start_ip6 (NMDhcpManager *self,
 	                     NULL,
 	                     needed_prefixes,
 	                     NULL,
+	                     NULL,
 	                     error);
 }
 

src/dhcp/nm-dhcp-manager.h

@@ -49,6 +49,7 @@ NMDhcpClient * nm_dhcp_manager_start_ip4     (NMDhcpManager *manager,
                                               const char *dhcp_anycast_addr,
                                               const char *last_ip_address,
                                               GBytes *vendor_class_identifier,
+                                              const char *const *reject_servers,
                                               GError **error);
 
 NMDhcpClient * nm_dhcp_manager_start_ip6     (NMDhcpManager *manager,

src/dhcp/nm-dhcp-nettools.c

@@ -1072,16 +1072,31 @@ dhcp4_event_handle (NMDhcpNettools *self,
                     NDhcp4ClientEvent *event)
 {
 	NMDhcpNettoolsPrivate *priv = NM_DHCP_NETTOOLS_GET_PRIVATE (self);
+	struct in_addr server_id;
+	char addr_str[INET_ADDRSTRLEN];
 	int r;
 
 	_LOGT ("client event %d", event->event);
 
 	switch (event->event) {
 	case N_DHCP4_CLIENT_EVENT_OFFER:
-		/* always accept the first lease */
+		r = n_dhcp4_client_lease_get_server_identifier (event->offer.lease, &server_id);
-		r = n_dhcp4_client_lease_select (event->offer.lease);
+		if (r) {
-		if (r)
 			_LOGW ("selecting lease failed: %d", r);
+			return TRUE;
+		}
+
+		if (nm_dhcp_client_server_id_is_rejected (NM_DHCP_CLIENT (self), &server_id)) {
+			_LOGD ("server-id %s is in the reject-list, ignoring",
+			       nm_utils_inet_ntop (AF_INET, &server_id, addr_str));
+			return TRUE;
+		}
+
+		r = n_dhcp4_client_lease_select (event->offer.lease);
+		if (r) {
+			_LOGW ("selecting lease failed: %d", r);
+			return TRUE;
+		}
 		break;
 	case N_DHCP4_CLIENT_EVENT_RETRACTED:
 	case N_DHCP4_CLIENT_EVENT_EXPIRED:

src/dhcp/nm-dhcp-systemd.c

@@ -524,6 +524,10 @@ dhcp_event_cb (sd_dhcp_client *client, int event, gpointer user_data)
 {
 	NMDhcpSystemd *self = NM_DHCP_SYSTEMD (user_data);
 	NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE (self);
+	char addr_str[INET_ADDRSTRLEN];
+	sd_dhcp_lease *lease;
+	struct in_addr addr;
+	int r;
 
 	nm_assert (priv->client4 == client);
 
@@ -544,6 +548,17 @@ dhcp_event_cb (sd_dhcp_client *client, int event, gpointer user_data)
 		bound4_handle (self, FALSE);
 		break;
 	case SD_DHCP_CLIENT_EVENT_SELECTING:
+		r = sd_dhcp_client_get_lease (priv->client4, &lease);
+		if (r < 0)
+			return r;
+		r = sd_dhcp_lease_get_server_identifier (lease, &addr);
+		if (r < 0)
+			return r;
+		if (nm_dhcp_client_server_id_is_rejected (NM_DHCP_CLIENT (user_data), &addr)) {
+			_LOGD ("server-id %s is in the reject-list, ignoring",
+			       nm_utils_inet_ntop (AF_INET, &addr, addr_str));
+			return -ENOMSG;
+		}
 		break;
 	default:
 		_LOGW ("unhandled DHCP event %d", event);

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

@@ -55,6 +55,7 @@ test_config (const char *orig,
 	                                      use_fqdn,
 	                                      hostname_flags,
 	                                      mud_url,
+	                                      NULL,
 	                                      "/path/to/dhclient.conf",
 	                                      orig,
 	                                      &new_client_id);

src/nm-iface-helper.c

@@ -539,6 +539,7 @@ main (int argc, char *argv[])
 		                                          NULL,
 		                                          global_opt.dhcp4_address,
 		                                          NULL,
+		                                          NULL,
 		                                          &error);
 		if (!dhcp4_client)
 			g_error ("failure to start DHCP: %s", error->message);