offers: include the payer_note field in the invoice if it's in the re…

…quest.

And list it in bolt12-cli decode, and the `decode` command.

Signed-off-by: Rusty Russell <[email protected]>

devtools/bolt12-cli.c

@@ -373,6 +373,12 @@ static void print_payer_key(const struct pubkey32 *payer_key,
 	printf("\n");
 }
 
+static void print_payer_note(const char *payer_note)
+{
+	printf("payer_note: %.*s\n",
+	       (int)tal_bytelen(payer_note), payer_note);
+}
+
 static void print_timestamp(u64 timestamp)
 {
 	printf("timestamp: %"PRIu64" (%s)\n",
@@ -535,6 +541,8 @@ int main(int argc, char *argv[])
 			print_chains(invreq->chains);
 		if (must_have(invreq, payer_key))
 			print_payer_key(invreq->payer_key, invreq->payer_info);
+		if (invreq->payer_note)
+			print_payer_note(invreq->payer_note);
 		if (must_have(invreq, offer_id))
 			print_offer_id(invreq->offer_id);
 		if (must_have(invreq, amount))
@@ -627,6 +635,8 @@ int main(int argc, char *argv[])
 			print_payer_key(invoice->payer_key, invoice->payer_info);
 		if (must_have(invoice, timestamp))
 			print_timestamp(*invoice->timestamp);
+		if (invoice->payer_note)
+			print_payer_note(invoice->payer_note);
 		print_relative_expiry(invoice->timestamp,
 				      invoice->relative_expiry);
 		if (must_have(invoice, payment_hash))

plugins/offers.c

@@ -533,6 +533,9 @@ static void json_add_b12_invoice(struct json_stream *js,
 		json_add_pubkey32(js, "payer_key", invoice->payer_key);
 	if (invoice->payer_info)
 		json_add_hex_talarr(js, "payer_info", invoice->payer_info);
+	if (invoice->payer_note)
+		json_add_stringn(js, "payer_note", invoice->payer_note,
+				 tal_bytelen(invoice->payer_note));
 
 	/* BOLT-offers #12:
 	 *   - MUST reject the invoice if `timestamp` is not present.
@@ -663,6 +666,9 @@ static void json_add_invoice_request(struct json_stream *js,
 	}
 	if (invreq->payer_info)
 		json_add_hex_talarr(js, "payer_info", invreq->payer_info);
+	if (invreq->payer_note)
+		json_add_stringn(js, "payer_note", invreq->payer_note,
+				 tal_bytelen(invreq->payer_note));
 
 	/* BOLT-offers #12:
 	 *  - MUST fail the request if there is no `payer_signature` field.

plugins/offers_invreq_hook.c

@@ -819,6 +819,14 @@ static struct command_result *listoffers_done(struct command *cmd,
 	ir->inv->payer_info
 		= tal_dup_talarr(ir->inv, u8, ir->invreq->payer_info);
 
+	/* BOLT-offers #12:
+	 * - MUST set (or not set) `payer_note` exactly as the invoice_request
+	 *   did, or MUST not set it.
+	 */
+	/* i.e. we don't have to do anything, but we do. */
+	ir->inv->payer_note
+		= tal_dup_talarr(ir->inv, char, ir->invreq->payer_note);
+
 	randombytes_buf(&ir->preimage, sizeof(ir->preimage));
 	ir->inv->payment_hash = tal(ir->inv, struct sha256);
 	sha256(ir->inv->payment_hash, &ir->preimage, sizeof(ir->preimage));