Merge pull request #1703 from pi-hole/fix/delete_dhcp_lease

Managing DHCP leases is only possible when the DHCP server is enabled

src/api/dhcp.c

@@ -73,7 +73,7 @@ int api_dhcp_leases_GET(struct ftl_conn *api)
 }
 
 // defined in dnsmasq_interface.c
-extern bool FTL_unlink_DHCP_lease(const char *ipaddr);
+extern bool FTL_unlink_DHCP_lease(const char *ipaddr, const char **hint);
 
 // Delete DHCP leases
 int api_dhcp_leases_DELETE(struct ftl_conn *api)
@@ -92,7 +92,18 @@ int api_dhcp_leases_DELETE(struct ftl_conn *api)
 
 	// Delete lease
 	log_debug(DEBUG_API, "Deleting DHCP lease for address %s", api->item);
-	const bool found = FTL_unlink_DHCP_lease(api->item);
+
+	const char *hint = NULL;
+	const bool found = FTL_unlink_DHCP_lease(api->item, &hint);
+	if(!found && hint != NULL)
+	{
+		// Send error when something went wrong (hint is not NULL)
+		return send_json_error(api,
+		                       400,
+		                       "bad_request",
+		                       "Failed to delete DHCP lease",
+		                       hint);
+	}
 
 	// Send empty reply with codes:
 	// - 204 No Content (if a lease was deleted)

src/api/docs/content/specs/dhcp.yaml

@@ -36,6 +36,7 @@ components:
         operationId: "delete_dhcp"
         description: |
           This API hook removes a currently active DHCP lease.
+          Managing DHCP leases is only possible when the DHCP server is enabled.
           *Note:* There will be no content on success.
         responses:
           '204':

src/dnsmasq_interface.c

@@ -3244,12 +3244,18 @@ void FTL_TCP_worker_created(const int confd)
 	gravityDB_forked();
 }
 
-bool FTL_unlink_DHCP_lease(const char *ipaddr)
+bool FTL_unlink_DHCP_lease(const char *ipaddr, const char **hint)
 {
 	struct dhcp_lease *lease;
 	union all_addr addr;
 	const time_t now = dnsmasq_time();
 
+	if(!daemon->dhcp)
+	{
+		*hint = "DHCP is not enabled";
+		return false;
+	}
+
 	// Try to extract IP address
 	if (inet_pton(AF_INET, ipaddr, &addr.addr4) > 0)
 	{
@@ -3263,7 +3269,8 @@ bool FTL_unlink_DHCP_lease(const char *ipaddr)
 #endif
 	else
 	{
-		// Invalid IP address or no lease found
+		// Invalid IP address
+		*hint = "invalid target address (neither IPv4 nor IPv6)";
 		return false;
 	}
 
@@ -3280,6 +3287,11 @@ bool FTL_unlink_DHCP_lease(const char *ipaddr)
 		// (variable lease.c:dns_dirty is used here)
 		lease_update_dns(0);
 	}
+	else
+	{
+		*hint = NULL;
+		return false;
+	}
 
 	// Return success
 	return true;

src/dnsmasq_interface.h

@@ -46,7 +46,7 @@ void FTL_dnsmasq_reload(void);
 void FTL_TCP_worker_created(const int confd);
 void FTL_TCP_worker_terminating(bool finished);
 
-bool FTL_unlink_DHCP_lease(const char *ipaddr);
+bool FTL_unlink_DHCP_lease(const char *ipaddr, const char **hint);
 
 // defined in src/dnsmasq/cache.c
 extern char *querystr(char *desc, unsigned short type);