invoice: option to expose/not-expose private channels.

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

CHANGELOG.md

@@ -40,7 +40,7 @@ This release named by @molxyz and [@ctrlbreak](https://twitter.com/ctrlbreak).
 - JSON API: use `\n\n` to terminate responses, for simplified parsing (pylightning now relies on this)
 - JSON API: `fundchannel` now includes an `announce` option, when false it will keep channel private. Defaults to true.
 - JSON API: `listpeers`'s `channels` now includes a `private` flag to indicate if channel is announced or not.
-- JSON API: `invoice` route hints may now include private channels if you have no public ones.
+- JSON API: `invoice` route hints may now include private channels if you have no public ones, unless new option `exposeprivatechannels` is false.
 - Plugins: experimental plugin support for `lightningd`, including option passthrough and JSON-RPC passthrough.
 
 ### Changed

contrib/pylightning/lightning/lightning.py

@@ -175,7 +175,7 @@ class LightningRpc(UnixDomainSocketRpc):
         }
         return self.call("listchannels", payload)
 
-    def invoice(self, msatoshi, label, description, expiry=None, fallbacks=None, preimage=None):
+    def invoice(self, msatoshi, label, description, expiry=None, fallbacks=None, preimage=None, exposeprivatechannels=None):
         """
         Create an invoice for {msatoshi} with {label} and {description} with
         optional {expiry} seconds (default 1 hour)
@@ -186,7 +186,8 @@ class LightningRpc(UnixDomainSocketRpc):
             "description": description,
             "expiry": expiry,
             "fallbacks": fallbacks,
-            "preimage": preimage
+            "preimage": preimage,
+            "exposeprivatechannels": exposeprivatechannels
         }
         return self.call("invoice", payload)
 

doc/lightning-invoice.7

@@ -2,12 +2,12 @@
 .\"     Title: lightning-invoice
 .\"    Author: [see the "AUTHOR" section]
 .\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
-.\"      Date: 09/27/2018
+.\"      Date: 12/17/2018
 .\"    Manual: \ \&
 .\"    Source: \ \&
 .\"  Language: English
 .\"
-.TH "LIGHTNING\-INVOICE" "7" "09/27/2018" "\ \&" "\ \&"
+.TH "LIGHTNING\-INVOICE" "7" "12/17/2018" "\ \&" "\ \&"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -31,10 +31,10 @@
 lightning-invoice \- Command for accepting payments\&.
 .SH "SYNOPSIS"
 .sp
-\fBinvoice\fR \fImsatoshi\fR \fIlabel\fR \fIdescription\fR [\fIexpiry\fR] [\fIfallbacks\fR] [\fIpreimage\fR]
+\fBinvoice\fR \fImsatoshi\fR \fIlabel\fR \fIdescription\fR [\fIexpiry\fR] [\fIfallbacks\fR] [\fIpreimage\fR] [\fIexposeprivatechannels\fR]
 .SH "DESCRIPTION"
 .sp
-The \fBinvoice\fR RPC command creates the expectation of a payment of a given amount of milli\-satoshi: it returns a unique token which another lightning daemon can use to pay this invoice\&.
+The \fBinvoice\fR RPC command creates the expectation of a payment of a given amount of milli\-satoshi: it returns a unique token which another lightning daemon can use to pay this invoice\&. This token includes a \fIroute hint\fR description of an incoming channel with capacity to pay the invoice, if any exists\&.
 .sp
 The \fImsatoshi\fR can be the string "any", which creates an invoice that can be paid with any amount\&.
 .sp
@@ -47,6 +47,8 @@ The \fIexpiry\fR is optionally the number of seconds the invoice is valid for\&.
 The \fIfallbacks\fR array is one or more fallback addresses to include in the invoice (in order from most\-preferred to least): note that these arrays are not currently tracked to fulfill the invoice\&.
 .sp
 The \fIpreimage\fR is a 64\-digit hex string to be used as payment preimage for the created invoice\&. By default, if unspecified, lightningd will generate a secure pseudorandom preimage seeded from an appropriate entropy source on your system\&. \fBIMPORTANT\fR: if you specify the \fIpreimage\fR, you are responsible, to ensure appropriate care for generating using a secure pseudorandom generator seeded with sufficient entropy, and keeping the preimage secret\&. This parameter is an advanced feature intended for use with cutting\-edge cryptographic protocols and should not be used unless explicitly needed\&.
+.sp
+The \fIexposeprivatechannels\fR includes unpublished channels in the selection of channels for the route hint; by default they are excluded\&.
 .SH "RETURN VALUE"
 .sp
 On success, a hash is returned as \fIpayment_hash\fR to be given to the payer, and the \fIexpiry_time\fR as a UNIX timestamp\&. It also returns a BOLT11 invoice as \fIbolt11\fR to be given to the payer\&.

doc/lightning-invoice.7.txt

@@ -8,13 +8,15 @@ lightning-invoice - Command for accepting payments.
 
 SYNOPSIS
 --------
-*invoice* 'msatoshi' 'label' 'description' ['expiry'] ['fallbacks'] ['preimage']
+*invoice* 'msatoshi' 'label' 'description' ['expiry'] ['fallbacks'] ['preimage'] ['exposeprivatechannels']
 
 DESCRIPTION
 -----------
 The *invoice* RPC command creates the expectation of a payment of a
 given amount of milli-satoshi: it returns a unique token which another
-lightning daemon can use to pay this invoice.
+lightning daemon can use to pay this invoice.  This token includes a
+'route hint' description of an incoming channel with capacity to pay
+the invoice, if any exists.
 
 The 'msatoshi' can be the string "any", which creates an invoice
 that can be paid with any amount.
@@ -48,6 +50,11 @@ secret.
 This parameter is an advanced feature intended for use with cutting-edge
 cryptographic protocols and should not be used unless explicitly needed.
 
+If specified, 'exposeprivatechannels' overrides the default route hint
+logic, which will use unpublished channels only if there are no
+published channels.  If 'true' unpublished channels are always
+considered as a route hint candidate; if 'false', never.
+
 RETURN VALUE
 ------------
 

gossipd/gossip_wire.csv

@@ -144,6 +144,7 @@ gossip_dev_memleak_reply,,leak,bool
 
 # master -> gossipd: get route_info for our incoming channels
 gossip_get_incoming_channels,3025
+gossip_get_incoming_channels,,private_too,?bool
 
 # gossipd -> master: here they are.
 gossip_get_incoming_channels_reply,3125

gossipd/gossipd.c

@@ -2119,6 +2119,18 @@ static bool node_has_public_channels(const struct node *peer,
 	return false;
 }
 
+/*~ The `exposeprivate` flag is a trinary: NULL == dynamic, otherwise
+ * value decides.  Thus, we provide two wrappers for clarity: */
+static bool never_expose(bool *exposeprivate)
+{
+	return exposeprivate && !*exposeprivate;
+}
+
+static bool always_expose(bool *exposeprivate)
+{
+	return exposeprivate && *exposeprivate;
+}
+
 /*~ For routeboost, we offer payers a hint of what incoming channels might
  * have capacity for their payment.  To do this, lightningd asks for the
  * information about all channels to this node; but gossipd doesn't know about
@@ -2130,11 +2142,20 @@ static struct io_plan *get_incoming_channels(struct io_conn *conn,
 	struct node *node;
 	struct route_info *public = tal_arr(tmpctx, struct route_info, 0);
 	struct route_info *private = tal_arr(tmpctx, struct route_info, 0);
-	bool has_public = false;
+	bool has_public;
+	bool *exposeprivate;
 
-	if (!fromwire_gossip_get_incoming_channels(msg))
+	if (!fromwire_gossip_get_incoming_channels(tmpctx, msg, &exposeprivate))
 		master_badmsg(WIRE_GOSSIP_GET_INCOMING_CHANNELS, msg);
 
+	status_trace("exposeprivate = %s",
+		     exposeprivate ? (*exposeprivate ? "TRUE" : "FALSE") : "NULL");
+	status_trace("msg = %s", tal_hex(tmpctx, msg));
+	status_trace("always_expose = %u, never_expose = %u",
+		     always_expose(exposeprivate), never_expose(exposeprivate));
+
+	has_public = always_expose(exposeprivate);
+
 	node = get_node(daemon->rstate, &daemon->rstate->local_id);
 	if (node) {
 		for (size_t i = 0; i < tal_count(node->chans); i++) {
@@ -2160,7 +2181,7 @@ static struct io_plan *get_incoming_channels(struct io_conn *conn,
 			if (!node_has_public_channels(other_node(node, c), c))
 				continue;
 
-			if (is_chan_public(c))
+			if (always_expose(exposeprivate) || is_chan_public(c))
 				tal_arr_expand(&public, ri);
 			else
 				tal_arr_expand(&private, ri);
@@ -2168,7 +2189,7 @@ static struct io_plan *get_incoming_channels(struct io_conn *conn,
 	}
 
 	/* If no public channels (even deadend ones!), share private ones. */
-	if (!has_public)
+	if (!has_public && !never_expose(exposeprivate))
 		msg = towire_gossip_get_incoming_channels_reply(NULL, private);
 	else
 		msg = towire_gossip_get_incoming_channels_reply(NULL, public);

lightningd/invoice.c

@@ -308,6 +308,7 @@ static struct command_result *json_invoice(struct command *cmd,
 	const u8 **fallback_scripts = NULL;
 	u64 *expiry;
 	struct sha256 rhash;
+	bool *exposeprivate;
 
 	info = tal(cmd, struct invoice_info);
 	info->cmd = cmd;
@@ -319,6 +320,7 @@ static struct command_result *json_invoice(struct command *cmd,
 		   p_opt_def("expiry", param_u64, &expiry, 3600),
 		   p_opt("fallbacks", param_array, &fallbacks),
 		   p_opt("preimage", param_tok, &preimagetok),
+		   p_opt("exposeprivatechannels", param_bool, &exposeprivate),
 		   NULL))
 		return command_param_failed();
 
@@ -381,8 +383,10 @@ static struct command_result *json_invoice(struct command *cmd,
 	if (fallback_scripts)
 		info->b11->fallbacks = tal_steal(info->b11, fallback_scripts);
 
+	log_debug(cmd->ld->log, "exposeprivate = %s",
+		  exposeprivate ? (*exposeprivate ? "TRUE" : "FALSE") : "NULL");
 	subd_req(cmd, cmd->ld->gossip,
-		 take(towire_gossip_get_incoming_channels(NULL)),
+		 take(towire_gossip_get_incoming_channels(NULL, exposeprivate)),
 		 -1, 0, gossipd_incoming_channels_reply, info);
 
 	return command_still_pending(cmd);

lightningd/test/run-invoice-select-inchan.c

@@ -397,7 +397,7 @@ u8 *towire_errorfmt(const tal_t *ctx UNNEEDED,
 		    const char *fmt UNNEEDED, ...)
 { fprintf(stderr, "towire_errorfmt called!\n"); abort(); }
 /* Generated stub for towire_gossip_get_incoming_channels */
-u8 *towire_gossip_get_incoming_channels(const tal_t *ctx UNNEEDED)
+u8 *towire_gossip_get_incoming_channels(const tal_t *ctx UNNEEDED, const bool *private_too UNNEEDED)
 { fprintf(stderr, "towire_gossip_get_incoming_channels called!\n"); abort(); }
 /* Generated stub for towire_hsm_get_channel_basepoints */
 u8 *towire_hsm_get_channel_basepoints(const tal_t *ctx UNNEEDED, const struct pubkey *peerid UNNEEDED, u64 dbid UNNEEDED)

tests/test_invoices.py

@@ -194,6 +194,11 @@ def test_invoice_routeboost_private(node_factory, bitcoind):
     assert r['fee_proportional_millionths'] == 10
     assert r['cltv_expiry_delta'] == 6
 
+    # If we explicitly say not to, it won't expose.
+    inv = l2.rpc.invoice(msatoshi=123456, label="inv1", description="?", exposeprivatechannels=False)
+    assert 'warning_capacity' in inv
+    assert 'routes' not in l1.rpc.decodepay(inv['bolt11'])
+
     # The existence of a public channel, even without capacity, will suppress
     # the exposure of private channels.
     l3 = node_factory.get_node()
@@ -204,9 +209,21 @@ def test_invoice_routeboost_private(node_factory, bitcoind):
     # Make sure channel is totally public.
     wait_for(lambda: [c['public'] for c in l3.rpc.listchannels(scid)['channels']] == [True, True])
 
-    inv = l2.rpc.invoice(msatoshi=10**7, label="inv1", description="?")
+    inv = l2.rpc.invoice(msatoshi=10**7, label="inv2", description="?")
     assert 'warning_capacity' in inv
 
+    # Unless we tell it to include it.
+    inv = l2.rpc.invoice(msatoshi=10**7, label="inv3", description="?", exposeprivatechannels=True)
+    assert 'warning_capacity' not in inv
+    assert 'warning_offline' not in inv
+    # Route array has single route with single element.
+    r = only_one(only_one(l1.rpc.decodepay(inv['bolt11'])['routes']))
+    assert r['pubkey'] == l1.info['id']
+    assert r['short_channel_id'] == l1.rpc.listchannels()['channels'][0]['short_channel_id']
+    assert r['fee_base_msat'] == 1
+    assert r['fee_proportional_millionths'] == 10
+    assert r['cltv_expiry_delta'] == 6
+
 
 def test_invoice_expiry(node_factory, executor):
     l1, l2 = node_factory.line_graph(2, fundchannel=True)

tools/generate-wire.py

@@ -392,29 +392,34 @@ class Message(object):
                 self.print_fromwire_array('*' + f.name, subcalls, basetype, f,
                                           '*' + f.name, f.lenvar)
             else:
+                if f.optional:
+                    assignable = f.fieldtype.is_assignable()
+                    deref = '*'
+                else:
+                    deref = ''
+                    assignable = f.is_assignable()
+
+                if assignable:
+                    if f.is_len_var:
+                        s = '{} = fromwire_{}(&cursor, &plen);'.format(f.name, basetype)
+                    else:
+                        s = '{}*{} = fromwire_{}(&cursor, &plen);'.format(deref, f.name, basetype)
+                elif basetype in varlen_structs:
+                    s = '{}*{} = fromwire_{}(ctx, &cursor, &plen);'.format(deref, f.name, basetype)
+                else:
+                    s = 'fromwire_{}(&cursor, &plen, {}{});'.format(basetype, deref, f.name)
+
                 if f.optional:
                     subcalls.append("if (!fromwire_bool(&cursor, &plen))\n"
                                     "*{} = NULL;\n"
                                     "else {{\n"
                                     "*{} = tal(ctx, {});\n"
-                                    "fromwire_{}(&cursor, &plen, *{});\n"
+                                    "{}\n"
                                     "}}"
                                     .format(f.name, f.name, f.fieldtype.name,
-                                            basetype, f.name))
-                elif f.is_assignable():
-                    subcalls.append("//3rd case {name}".format(name=f.name))
-                    if f.is_len_var:
-                        subcalls.append('{} = fromwire_{}(&cursor, &plen);'
-                                        .format(f.name, basetype))
+                                            s))
                 else:
-                        subcalls.append('*{} = fromwire_{}(&cursor, &plen);'
-                                        .format(f.name, basetype))
-                elif basetype in varlen_structs:
-                    subcalls.append('*{} = fromwire_{}(ctx, &cursor, &plen);'
-                                    .format(f.name, basetype))
-                else:
-                    subcalls.append('fromwire_{}(&cursor, &plen, {});'
-                                    .format(basetype, f.name))
+                    subcalls.append(s)
 
         return template.format(
             name=self.name,
@@ -481,12 +486,16 @@ class Message(object):
                 self.print_towire_array(subcalls, basetype, f, f.lenvar)
             else:
                 if f.optional:
+                    if f.fieldtype.is_assignable():
+                        deref = '*'
+                    else:
+                        deref = ''
                     subcalls.append("if (!{})\n"
                                     "towire_bool(&p, false);\n"
                                     "else {{\n"
                                     "towire_bool(&p, true);\n"
-                                    "towire_{}(&p, {});\n"
-                                    "}}".format(f.name, basetype, f.name))
+                                    "towire_{}(&p, {}{});\n"
+                                    "}}".format(f.name, basetype, deref, f.name))
                 else:
                     subcalls.append('towire_{}(&p, {});'
                                     .format(basetype, f.name))