sendpay: provide 'bolt11' parameter.

Without this, there's no proof of payment, since it is the signed invoice
that make the receipt valid.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - JSON API: `listchannels` now takes a `source` option to filter by node id.
 - JSON API: New command `paystatus` gives detailed information on `pay` commands.
 - JSON API: `getroute` `riskfactor` argument is simplified; `pay` now defaults to setting it to 10.
+- JSON API: `sendpay` now takes a `bolt11` field, and it's returned in `listpayments` and `waitsendpay`.
 - pylightning: New class 'Millisatoshi' can be used for JSON API, and new '_msat' fields are turned into this on reading.
 - JSON API: `fundchannel` and `withdraw` now have a new parameter `minconf` that limits coinselection to outputs that have at least `minconf` confirmations (default 1). (#2380)
 - JSON API: `listfunds` now displays addresses for all outputs owned by the wallet (#2387)

doc/lightning-sendpay.7

@@ -28,10 +28,10 @@
 .\" * MAIN CONTENT STARTS HERE *
 .\" -----------------------------------------------------------------
 .SH "NAME"
-lightning-sendpay \- Command for sending a payment via a route\&.
+lightning-sendpay \- Low\-level command for sending a payment via a route\&.
 .SH "SYNOPSIS"
 .sp
-\fBsendpay\fR \fIroute\fR \fIpayment_hash\fR [\fIdescription\fR] [\fImsatoshi\fR]
+\fBsendpay\fR \fIroute\fR \fIpayment_hash\fR [\fIdescription\fR] [\fImsatoshi\fR] [\fIbolt11\fR]
 .SH "DESCRIPTION"
 .sp
 The \fBsendpay\fR RPC command attempts to send funds associated with the given \fIpayment_hash\fR, along a route to the final destination in the route\&.
@@ -40,7 +40,7 @@ Generally, a client would call lightning\-getroute(7) to resolve a route, then u
 .sp
 The response will occur when the payment is on its way to the destination\&. The \fBsendpay\fR RPC command does not wait for definite success or definite failure of the payment\&. Instead, use the \fBwaitsendpay\fR RPC command to poll or wait for definite success or definite failure\&.
 .sp
-The \fIdescription\fR parameter, if provided, will be returned in \fIwaitsendpay\fR and \fIlistpayments\fR results\&.
+The \fIdescription\fR and \fIbolt11\fR parameters, if provided, will be returned in \fIwaitsendpay\fR and \fIlistpayments\fR results\&.
 .sp
 The \fImsatoshi\fR amount, if provided, is the amount that will be recorded as the target payment value\&. If not specified, it will be the final amount to the destination\&. If specified, then the final amount at the destination must be from the specified \fImsatoshi\fR to twice the specified \fImsatoshi\fR, inclusive\&. This is intended to obscure payments by overpaying slightly at the destination; the actual target payment is what should be specified as the \fImsatoshi\fR argument\&. \fImsatoshi\fR is in millisatoshi precision; it can be a whole number, or a whole number ending in \fImsat\fR or \fIsat\fR, or a number with three decimal places ending in \fIsat\fR, or a number with 1 to 11 decimal places ending in \fIbtc\fR\&.
 .sp

doc/lightning-sendpay.7.txt

@@ -4,11 +4,11 @@ LIGHTNING-SENDPAY(7)
 
 NAME
 ----
-lightning-sendpay - Command for sending a payment via a route.
+lightning-sendpay - Low-level command for sending a payment via a route.
 
 SYNOPSIS
 --------
-*sendpay* 'route' 'payment_hash' ['description'] ['msatoshi']
+*sendpay* 'route' 'payment_hash' ['description'] ['msatoshi'] ['bolt11']
 
 DESCRIPTION
 -----------
@@ -27,7 +27,7 @@ definite failure of the payment.
 Instead, use the *waitsendpay* RPC command to poll or wait for
 definite success or definite failure.
 
-The 'description' parameter, if provided, will be returned in
+The 'description' and 'bolt11' parameters, if provided, will be returned in
 'waitsendpay' and 'listpayments' results.
 
 The 'msatoshi' amount, if provided, is the amount that will be
@@ -44,7 +44,6 @@ be a whole number, or a whole number ending in 'msat' or 'sat', or a
 number with three decimal places ending in 'sat', or a number with 1
 to 11 decimal places ending in 'btc'.
 
-
 Once a payment has succeeded, calls to *sendpay* with the same 'payment_hash'
 but a different 'msatoshi' or destination will fail; this prevents
 accidental multiple payments.

lightningd/pay.c

@@ -101,6 +101,8 @@ json_add_payment_fields(struct json_stream *response,
 			     sizeof(*t->payment_preimage));
 	if (t->description)
 		json_add_string(response, "description", t->description);
+	if (t->bolt11)
+		json_add_string(response, "bolt11", t->bolt11);
 }
 
 static struct command_result *sendpay_success(struct command *cmd,
@@ -580,7 +582,8 @@ send_payment(struct lightningd *ld,
 	     const struct sha256 *rhash,
 	     const struct route_hop *route,
 	     struct amount_msat msat,
-	     const char *description TAKES)
+	     const char *description TAKES,
+	     const char *b11str TAKES)
 {
 	const u8 *onion;
 	u8 sessionkey[32];
@@ -720,6 +723,10 @@ send_payment(struct lightningd *ld,
 		payment->description = tal_strdup(payment, description);
 	else
 		payment->description = NULL;
+	if (b11str != NULL)
+		payment->bolt11 = tal_strdup(payment, b11str);
+	else
+		payment->bolt11 = NULL;
 
 	/* We write this into db when HTLC is actually sent. */
 	wallet_payment_setup(ld->wallet, payment);
@@ -743,7 +750,7 @@ static struct command_result *json_sendpay(struct command *cmd,
 	struct sha256 *rhash;
 	struct route_hop *route;
 	struct amount_msat *msat;
-	const char *description;
+	const char *description, *b11str;
 	struct command_result *res;
 
 	if (!param(cmd, buffer, params,
@@ -751,6 +758,7 @@ static struct command_result *json_sendpay(struct command *cmd,
 		   p_req("payment_hash", param_sha256, &rhash),
 		   p_opt("description", param_escaped_string, &description),
 		   p_opt("msatoshi", param_msat, &msat),
+		   p_opt("bolt11", param_string, &b11str),
 		   NULL))
 		return command_param_failed();
 
@@ -836,7 +844,7 @@ static struct command_result *json_sendpay(struct command *cmd,
 
 	res = send_payment(cmd->ld, cmd, rhash, route,
 			   msat ? *msat : route[routetok->size-1].amount,
-			   description);
+			   description, b11str);
 	if (res)
 		return res;
 	return command_still_pending(cmd);

wallet/db.c

@@ -359,6 +359,8 @@ char *dbmigrations[] = {
     /* Fix dangling peers with no channels. */
     "DELETE FROM peers WHERE id NOT IN (SELECT peer_id FROM channels);",
     "ALTER TABLE outputs ADD scriptpubkey BLOB;",
+    /* Keep bolt11 string for payments. */
+    "ALTER TABLE payments ADD bolt11 TEXT;",
     NULL,
 };
 

wallet/wallet.c

@@ -1722,8 +1722,9 @@ void wallet_payment_store(struct wallet *wallet,
 		"  route_nodes,"
 		"  route_channels,"
 		"  msatoshi_sent,"
-		"  description"
+		"  description,"
-		") VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?);");
+		"  bolt11"
+		") VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);");
 
 	sqlite3_bind_int(stmt, 1, payment->status);
 	sqlite3_bind_sha256(stmt, 2, &payment->payment_hash);
@@ -1745,6 +1746,13 @@ void wallet_payment_store(struct wallet *wallet,
 	else
 		sqlite3_bind_null(stmt, 10);
 
+	if (payment->bolt11 != NULL)
+		sqlite3_bind_text(stmt, 11, payment->bolt11,
+				  strlen(payment->bolt11),
+				  SQLITE_TRANSIENT);
+	else
+		sqlite3_bind_null(stmt, 11);
+
 	db_exec_prepared(wallet->db, stmt);
 
 	tal_free(payment);
@@ -1804,6 +1812,12 @@ static struct wallet_payment *wallet_stmt2payment(const tal_t *ctx,
 	else
 		payment->description = NULL;
 
+	if (sqlite3_column_type(stmt, 12) != SQLITE_NULL)
+		payment->bolt11 = tal_strdup(payment,
+					     (const char *)sqlite3_column_text(stmt, 12));
+	else
+		payment->bolt11 = NULL;
+
 	return payment;
 }
 
@@ -1811,7 +1825,7 @@ static struct wallet_payment *wallet_stmt2payment(const tal_t *ctx,
 #define PAYMENT_FIELDS                                                         \
 	"id, status, destination, msatoshi, payment_hash, timestamp, "         \
 	"payment_preimage, path_secrets, route_nodes, route_channels, "        \
-	"msatoshi_sent, description "
+	"msatoshi_sent, description, bolt11 "
 
 struct wallet_payment *
 wallet_payment_by_hash(const tal_t *ctx, struct wallet *wallet,

wallet/wallet.h

@@ -224,6 +224,8 @@ struct wallet_payment {
 	struct secret *path_secrets;
 	struct pubkey *route_nodes;
 	struct short_channel_id *route_channels;
+	/* bolt11 string; NULL for old payments. */
+	const char *bolt11;
 
 	/* The description of the payment. Must support `tal_len` */
 	const char *description;