feat: Adds canton sign txn external support (namespace delegation)

apps/canton_app/canton_context.h

@@ -18,6 +18,7 @@
 #include <stdint.h>
 
 #include "canton/sign_txn.pb.h"
+#include "canton/sign_txn_external.pb.h"
 #include "sha2.h"
 
 /*****************************************************************************
@@ -63,6 +64,8 @@
 #define PREAPPROVAL_TXN_TYPE_TEXT "Enable Transfer Pre-approval"
 #define MERGE_DELEGATION_PROPOSAL_TXN_TYPE_TEXT "Enable UTXO Management"
 
+#define NAMESPACE_DELEGATION_TXN_TYPE_TEXT "Namespace Delegation"
+
 /*****************************************************************************
  * TYPEDEFS
  *****************************************************************************/
@@ -128,6 +131,19 @@ typedef struct {
   uint8_t public_key[CANTON_PUB_KEY_SIZE];
 } canton_unsigned_topology_txn;
 
+typedef struct {
+  uint8_t target_public_key[CANTON_PUB_KEY_SIZE];
+  char namespace[CANTON_FINGERPRINT_STR_SIZE];
+} canton_namespace_delegation_txn_display_info_t;
+
+typedef struct {
+  canton_sign_txn_external_supported_txn_types_t txn_type;
+  uint8_t hash[CANTON_HASH_SIZE];
+  union {
+    canton_namespace_delegation_txn_display_info_t namespace_delegation;
+  } display_info;
+} canton_unsigned_txn_external_info_t;
+
 /*****************************************************************************
  * EXPORTED VARIABLES
  *****************************************************************************/

apps/canton_app/canton_main.c

@@ -143,6 +143,11 @@ void canton_main(usb_event_t usb_event, const void *canton_app_config) {
       break;
     }
 
+    case CANTON_QUERY_SIGN_TXN_EXTERNAL_TAG: {
+      canton_sign_txn_external(&query);
+      break;
+    }
+
     /* Incase we encounter an invalid query */
     default: {
       canton_send_error(ERROR_COMMON_ERROR_CORRUPT_DATA_TAG,

apps/canton_app/canton_priv.h

@@ -17,6 +17,7 @@
 #include <stdint.h>
 
 #include "canton/core.pb.h"
+#include "canton/sign_txn_external.pb.h"
 #include "canton_context.h"
 #include "canton_txn_encoding.h"
 #include "sha2.h"
@@ -48,6 +49,11 @@ typedef struct {
 
 } canton_topology_txn_context_t;
 
+typedef struct {
+  canton_sign_txn_external_initiate_request_t init_info;
+  canton_unsigned_txn_external_info_t unsigned_txn_external_info;
+} canton_txn_external_context_t;
+
 /*****************************************************************************
  * EXPORTED VARIABLES
  *****************************************************************************/
@@ -86,4 +92,13 @@ void canton_sign_transaction(canton_query_t *query);
  */
 void canton_sign_topology_transaction(canton_query_t *query);
 
+/**
+ * @brief Entry point for sign_txn_external type queries
+ * @details Function handles complete flow required to sign and required
+ * transaction, this includes: recieving further data, parsing and validating
+ * data, user confirmation, returning data to the host. And incase of any error,
+ * returns error to the host.
+ */
+void canton_sign_txn_external(canton_query_t *query);
+
 #endif