Merge pull request #24299 from yuwata/dhcp6-no-binding

dhcp6: gracefully handle NoBinding error

src/libsystemd-network/dhcp6-protocol.c

@@ -82,3 +82,14 @@ static const char * const dhcp6_message_status_table[_DHCP6_STATUS_MAX] = {
 };
 
 DEFINE_STRING_TABLE_LOOKUP(dhcp6_message_status, DHCP6Status);
+
+int dhcp6_message_status_to_errno(DHCP6Status s) {
+        switch (s) {
+        case DHCP6_STATUS_SUCCESS:
+                return 0;
+        case DHCP6_STATUS_NO_BINDING:
+                return -EADDRNOTAVAIL;
+        default:
+                return -EINVAL;
+        }
+}

src/libsystemd-network/dhcp6-protocol.h

@@ -154,3 +154,4 @@ const char *dhcp6_message_type_to_string(DHCP6MessageType s) _const_;
 DHCP6MessageType dhcp6_message_type_from_string(const char *s) _pure_;
 const char *dhcp6_message_status_to_string(DHCP6Status s) _const_;
 DHCP6Status dhcp6_message_status_from_string(const char *s) _pure_;
+int dhcp6_message_status_to_errno(DHCP6Status s);

src/libsystemd-network/fuzz-dhcp6-client.c

@@ -48,7 +48,7 @@ static void fuzz_client(sd_dhcp6_client *client, const uint8_t *data, size_t siz
                         assert_se(IN_SET(client->state, DHCP6_STATE_REQUEST, DHCP6_STATE_BOUND));
                         break;
                 case DHCP6_STATE_REQUEST:
-                        assert_se(client->state == DHCP6_STATE_BOUND);
+                        assert_se(IN_SET(client->state, DHCP6_STATE_BOUND, DHCP6_STATE_SOLICITATION));
                         break;
                 default:
                         assert_not_reached();

src/libsystemd-network/sd-dhcp6-client.c

@@ -543,13 +543,9 @@ static void client_notify(sd_dhcp6_client *client, int event) {
                 client->callback(client, event, client->userdata);
 }
 
-static void client_stop(sd_dhcp6_client *client, int error) {
-        DHCP6_CLIENT_DONT_DESTROY(client);
-
+static void client_cleanup(sd_dhcp6_client *client) {
         assert(client);
 
-        client_notify(client, error);
-
         client->lease = sd_dhcp6_lease_unref(client->lease);
 
         /* Reset IRT here. Otherwise, we cannot restart the client in the information requesting mode,
@@ -566,6 +562,16 @@ static void client_stop(sd_dhcp6_client *client, int error) {
         client_set_state(client, DHCP6_STATE_STOPPED);
 }
 
+static void client_stop(sd_dhcp6_client *client, int error) {
+        DHCP6_CLIENT_DONT_DESTROY(client);
+
+        assert(client);
+
+        client_notify(client, error);
+
+        client_cleanup(client);
+}
+
 static int client_append_common_options_in_managed_mode(
                 sd_dhcp6_client *client,
                 uint8_t **opt,
@@ -684,6 +690,9 @@ static int client_append_oro(sd_dhcp6_client *client, uint8_t **opt, size_t *opt
                 req_opts = client->req_opts;
         }
 
+        if (n == 0)
+                return 0;
+
         return dhcp6_option_append(opt, optlen, SD_DHCP6_OPTION_ORO, n * sizeof(be16_t), req_opts);
 }
 
@@ -1133,6 +1142,20 @@ static int client_process_reply(
                 return log_invalid_message_type(client, message);
 
         r = dhcp6_lease_new_from_message(client, message, len, timestamp, server_address, &lease);
+        if (r == -EADDRNOTAVAIL) {
+
+                /* If NoBinding status code is received, we cannot request the address anymore.
+                 * Let's restart transaction from the beginning. */
+
+                if (client->state == DHCP6_STATE_REQUEST)
+                        /* The lease is not acquired yet, hence it is not necessary to notify the restart. */
+                        client_cleanup(client);
+                else
+                        /* We need to notify the previous lease was expired. */
+                        client_stop(client, SD_DHCP6_CLIENT_EVENT_RESEND_EXPIRE);
+
+                return client_start_transaction(client, DHCP6_STATE_SOLICITATION);
+        }
         if (r < 0)
                 return log_dhcp6_client_errno(client, r, "Failed to process received reply message, ignoring: %m");
 

src/libsystemd-network/sd-dhcp6-lease.c

@@ -512,7 +512,7 @@ static int dhcp6_lease_parse_message(
                                 return log_dhcp6_client_errno(client, r, "Failed to parse status code: %m");
 
                         if (r > 0)
-                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL),
+                                return log_dhcp6_client_errno(client, dhcp6_message_status_to_errno(r),
                                                               "Received %s message with non-zero status: %s%s%s",
                                                               dhcp6_message_type_to_string(message->type),
                                                               strempty(msg), isempty(msg) ? "" : ": ",