invoice: add ctlv option.

This is required if we want to create a "bouncer" plugin (in my copious free time!)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `invoice` now takes an optional `cltv` parameter.

contrib/pyln-client/pyln/client/lightning.py

@@ -872,7 +872,7 @@ class LightningRpc(UnixDomainSocketRpc):
         }
         return self.call("help", payload)
 
-    def invoice(self, msatoshi, label, description, expiry=None, fallbacks=None, preimage=None, exposeprivatechannels=None):
+    def invoice(self, msatoshi, label, description, expiry=None, fallbacks=None, preimage=None, exposeprivatechannels=None, cltv=None):
         """
         Create an invoice for {msatoshi} with {label} and {description} with
         optional {expiry} seconds (default 1 week).
@@ -884,7 +884,8 @@ class LightningRpc(UnixDomainSocketRpc):
             "expiry": expiry,
             "fallbacks": fallbacks,
             "preimage": preimage,
-            "exposeprivatechannels": exposeprivatechannels
+            "exposeprivatechannels": exposeprivatechannels,
+            "cltv": cltv,
         }
         return self.call("invoice", payload)
 

doc/lightning-invoice.7

@@ -4,7 +4,7 @@ lightning-invoice - Command for accepting payments
 .SH SYNOPSIS
 
 \fBinvoice\fR \fImsatoshi\fR \fIlabel\fR \fIdescription\fR [\fIexpiry\fR]
-[\fIfallbacks\fR] [\fIpreimage\fR] [\fIexposeprivatechannels\fR]
+[\fIfallbacks\fR] [\fIpreimage\fR] [\fIexposeprivatechannels\fR] [\fIcltv\fR]
 
 .SH DESCRIPTION
 
@@ -71,6 +71,10 @@ other public channel)\. The selection uses some randomness to prevent
 probing, but favors channels that become more balanced after the
 payment\.
 
+
+If specified, \fIcltv\fR sets the \fImin_final_cltv_expiry\fR for the invoice\.
+Otherwise, it's set to the parameter \fBcltv-final\fR\.
+
 .SH RETURN VALUE
 
 On success, a hash is returned as \fIpayment_hash\fR to be given to the
@@ -124,4 +128,4 @@ Rusty Russell \fI<rusty@rustcorp.com.au\fR> is mainly responsible\.
 
 Main web site: \fIhttps://github.com/ElementsProject/lightning\fR
 
-\" SHA256STAMP:9a361884baa1bdceffb9861839ce4728cf38eaf5d08b3437ad4b3f5b9b42d8db
+\" SHA256STAMP:5a7792cb739f34adf7db346f3bd615816915230fcb8343af1b742336a677dbc2

doc/lightning-invoice.7.md

@@ -5,7 +5,7 @@ SYNOPSIS
 --------
 
 **invoice** *msatoshi* *label* *description* \[*expiry*\]
-\[*fallbacks*\] \[*preimage*\] \[*exposeprivatechannels*\]
+\[*fallbacks*\] \[*preimage*\] \[*exposeprivatechannels*\] \[*cltv*\]
 
 DESCRIPTION
 -----------
@@ -65,6 +65,9 @@ other public channel). The selection uses some randomness to prevent
 probing, but favors channels that become more balanced after the
 payment.
 
+If specified, *cltv* sets the *min_final_cltv_expiry* for the invoice.
+Otherwise, it's set to the parameter **cltv-final**.
+
 RETURN VALUE
 ------------
 

lightningd/invoice.c

@@ -1006,6 +1006,7 @@ static struct command_result *json_invoice(struct command *cmd,
 	struct sha256 rhash;
 	struct secret payment_secret;
 	struct preimage *preimage;
+	u32 *cltv;
 #if DEVELOPER
 	const jsmntok_t *routes;
 #endif
@@ -1022,6 +1023,8 @@ static struct command_result *json_invoice(struct command *cmd,
 		   p_opt("preimage", param_preimage, &preimage),
 		   p_opt("exposeprivatechannels", param_chanhints,
 			 &info->chanhints),
+		   p_opt_def("cltv", param_number, &cltv,
+			     cmd->ld->config.cltv_final),
 #if DEVELOPER
 		   p_opt("dev-routes", param_array, &routes),
 #endif
@@ -1081,7 +1084,7 @@ static struct command_result *json_invoice(struct command *cmd,
 	info->b11->timestamp = time_now().ts.tv_sec;
 	info->b11->payment_hash = rhash;
 	info->b11->receiver_id = cmd->ld->id;
-	info->b11->min_final_cltv_expiry = cmd->ld->config.cltv_final;
+	info->b11->min_final_cltv_expiry = *cltv;
 	info->b11->expiry = *expiry;
 	info->b11->description = tal_steal(info->b11, desc_val);
 	info->b11->description_hash = NULL;

tests/test_invoices.py

@@ -30,6 +30,7 @@ def test_invoice(node_factory, chainparams):
     assert b11['fallbacks'][0]['type'] == 'P2WPKH'
     assert b11['fallbacks'][1]['addr'] == addr2
     assert b11['fallbacks'][1]['type'] == 'P2SH'
+    assert b11['min_final_cltv_expiry'] == 5
     # There's no incoming channel, so no routeboost
     assert 'routes' not in b11
     assert 'warning_capacity' in inv
@@ -58,6 +59,11 @@ def test_invoice(node_factory, chainparams):
         l2.rpc.invoice(4294967295 + 1, 'inv3', '?')
     l2.rpc.invoice(4294967295, 'inv3', '?')
 
+    # Test cltv option.
+    inv = l1.rpc.invoice(123000, 'label3', 'description', '3700', cltv=99)
+    b11 = l1.rpc.decodepay(inv['bolt11'])
+    assert b11['min_final_cltv_expiry'] == 99
+
 
 def test_invoice_zeroval(node_factory):
     """A zero value invoice is unpayable, did you mean 'any'?"""