lnrpc: add AMPRecord to Hop

lnrpc/routerrpc/router.swagger.json

@@ -441,6 +441,23 @@
       ],
       "default": "IN_FLIGHT"
     },
+    "lnrpcAMPRecord": {
+      "type": "object",
+      "properties": {
+        "root_share": {
+          "type": "string",
+          "format": "byte"
+        },
+        "set_id": {
+          "type": "string",
+          "format": "byte"
+        },
+        "child_index": {
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
     "lnrpcChannelPoint": {
       "type": "object",
       "properties": {
@@ -677,7 +694,11 @@
         },
         "mpp_record": {
           "$ref": "#/definitions/lnrpcMPPRecord",
-          "description": "An optional TLV record that signals the use of an MPP payment. If present,\nthe receiver will enforce that that the same mpp_record is included in the\nfinal hop payload of all non-zero payments in the HTLC set. If empty, a\nregular single-shot payment is or was attempted."
+          "description": "An optional TLV record that signals the use of an MPP payment. If present,\nthe receiver will enforce that the same mpp_record is included in the final\nhop payload of all non-zero payments in the HTLC set. If empty, a regular\nsingle-shot payment is or was attempted."
+        },
+        "amp_record": {
+          "$ref": "#/definitions/lnrpcAMPRecord",
+          "description": "An optional TLV record that signals the use of an AMP payment. If present,\nthe receiver will treat all received payments including the same\n(payment_addr, set_id) pair  as being part of one logical payment. The\npayment will be settled by XORing the root_share's together and deriving the\nchild hashes and preimages according to BOLT XX. Must be used in conjunction\nwith mpp_record."
         },
         "custom_records": {
           "type": "object",

lnrpc/rpc.proto

@@ -2493,12 +2493,22 @@ message Hop {
 
     /*
     An optional TLV record that signals the use of an MPP payment. If present,
-    the receiver will enforce that that the same mpp_record is included in the
+    the receiver will enforce that the same mpp_record is included in the final
-    final hop payload of all non-zero payments in the HTLC set. If empty, a
+    hop payload of all non-zero payments in the HTLC set. If empty, a regular
-    regular single-shot payment is or was attempted.
+    single-shot payment is or was attempted.
     */
     MPPRecord mpp_record = 10;
 
+    /*
+    An optional TLV record that signals the use of an AMP payment. If present,
+    the receiver will treat all received payments including the same
+    (payment_addr, set_id) pair  as being part of one logical payment. The
+    payment will be settled by XORing the root_share's together and deriving the
+    child hashes and preimages according to BOLT XX. Must be used in conjunction
+    with mpp_record.
+    */
+    AMPRecord amp_record = 12;
+
     /*
     An optional set of key-value TLV records. This is useful within the context
     of the SendToRoute call as it allows callers to specify arbitrary K-V pairs
@@ -2525,6 +2535,14 @@ message MPPRecord {
     int64 total_amt_msat = 10;
 }
 
+message AMPRecord {
+    bytes root_share = 1;
+
+    bytes set_id = 2;
+
+    uint32 child_index = 3;
+}
+
 /*
 A path through the channel graph which runs over one or more channels in
 succession. This struct carries all the information required to craft the

lnrpc/rpc.swagger.json

@@ -2536,6 +2536,23 @@
       },
       "description": "Details specific to AMP HTLCs."
     },
+    "lnrpcAMPRecord": {
+      "type": "object",
+      "properties": {
+        "root_share": {
+          "type": "string",
+          "format": "byte"
+        },
+        "set_id": {
+          "type": "string",
+          "format": "byte"
+        },
+        "child_index": {
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
     "lnrpcAbandonChannelResponse": {
       "type": "object"
     },
@@ -4025,7 +4042,11 @@
         },
         "mpp_record": {
           "$ref": "#/definitions/lnrpcMPPRecord",
-          "description": "An optional TLV record that signals the use of an MPP payment. If present,\nthe receiver will enforce that that the same mpp_record is included in the\nfinal hop payload of all non-zero payments in the HTLC set. If empty, a\nregular single-shot payment is or was attempted."
+          "description": "An optional TLV record that signals the use of an MPP payment. If present,\nthe receiver will enforce that the same mpp_record is included in the final\nhop payload of all non-zero payments in the HTLC set. If empty, a regular\nsingle-shot payment is or was attempted."
+        },
+        "amp_record": {
+          "$ref": "#/definitions/lnrpcAMPRecord",
+          "description": "An optional TLV record that signals the use of an AMP payment. If present,\nthe receiver will treat all received payments including the same\n(payment_addr, set_id) pair  as being part of one logical payment. The\npayment will be settled by XORing the root_share's together and deriving the\nchild hashes and preimages according to BOLT XX. Must be used in conjunction\nwith mpp_record."
         },
         "custom_records": {
           "type": "object",