When opening, reserve inputs for 2016 blocks.

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

@@ -1246,22 +1246,24 @@ def txsend(self, txid):
         }
         return self.call("txsend", payload)
 
-    def reserveinputs(self, psbt, exclusive=True):
+    def reserveinputs(self, psbt, exclusive=True, reserve=None):
         """
         Reserve any inputs in this psbt.
         """
         payload = {
             "psbt": psbt,
             "exclusive": exclusive,
+            "reserve": reserve,
         }
         return self.call("reserveinputs", payload)
 
-    def unreserveinputs(self, psbt):
+    def unreserveinputs(self, psbt, reserve=None):
         """
         Unreserve (or reduce reservation) on any UTXOs in this psbt were previously reserved.
         """
         payload = {
             "psbt": psbt,
+            "reserve": reserve,
         }
         return self.call("unreserveinputs", payload)
 
@@ -1308,12 +1310,13 @@ def signpsbt(self, psbt, signonly=None):
         }
         return self.call("signpsbt", payload)
 
-    def sendpsbt(self, psbt):
+    def sendpsbt(self, psbt, reserve=None):
         """
         Finalize extract and broadcast a PSBT
         """
         payload = {
             "psbt": psbt,
+            "reserve": reserve,
         }
         return self.call("sendpsbt", payload)
 

doc/lightning-fundpsbt.7.md

@@ -33,8 +33,10 @@ added any inputs.
 *minconf* specifies the minimum number of confirmations that used
 outputs should have. Default is 1.
 
-*reserve* is a boolean: if true (the default), then *reserveinputs* is
-called (successfully, with *exclusive* true) on the returned PSBT.
+*reserve* is either boolean or a number: if *true* or a non-zero
+number then *reserveinputs* is called (successfully, with
+*exclusive* true) on the returned PSBT for this number of blocks (or
+72 blocks if *reserve* is simply *true*).
 
 *locktime* is an optional locktime: if not set, it is set to a recent
 block height.
@@ -77,8 +79,8 @@ available.  This could be zero, or dust.  If *satoshi* was "all",
 then *excess_msat* is the entire amount once fees are subtracted
 for the weights of the inputs and startweight.
 
-If *reserve* was true, then a *reservations* array is returned,
-exactly like *reserveinputs*.
+If *reserve* was *true* or a non-zero number, then a *reservations*
+array is returned, exactly like *reserveinputs*.
 
 If *excess_as_change* is true and the excess is enough to cover
 an additional output above the `dust_limit`, then an output is

doc/lightning-listfunds.7.md

@@ -34,6 +34,7 @@ Each entry in *outputs* will include:
 -   *redeemscript* (the redeemscript of the output, in hex, only if it's p2sh-wrapped)
 -   *status* (whether *unconfirmed*, *confirmed*, or *spent*)
 -   *reserved* (whether this is UTXO is currently reserved for an in-flight tx)
+-   *reserved_to_block* (when reservation expires, if *reserved* is true)
 
 Each entry in *channels* will include:
 -   *peer\_id* - the peer with which the channel is opened.

doc/lightning-reserveinputs.7.md

@@ -4,7 +4,7 @@ lightning-reserveinputs -- Construct a transaction and reserve the UTXOs it spen
 SYNOPSIS
 --------
 
-**reserveinputs** *psbt* [*exclusive*]
+**reserveinputs** *psbt* [*exclusive*] [*reserve*]
 
 DESCRIPTION
 -----------
@@ -18,6 +18,8 @@ Normally the command will fail (with no reservations made) if an input
 is already reserved.  If *exclusive* is set to *False*, then existing
 reservations are simply extended, rather than causing failure.
 
+By default, reservations are for the next 72 blocks (approximately 6
+hours), but this can be changed by setting *reserve*.
 
 RETURN VALUE
 ------------

doc/lightning-sendpsbt.7.md

@@ -4,14 +4,15 @@ lightning-sendpsbt -- Command to finalize, extract and send a partially signed b
 SYNOPSIS
 --------
 
-**sendpsbt** *psbt*
+**sendpsbt** *psbt* [*reserve*]
 
 DESCRIPTION
 -----------
 
 The **sendpsbt** is a low-level RPC command which sends a fully-signed PSBT.
 
 - *psbt*: A string that represents psbt value.
+- *reserve*: an optional number of blocks to increase reservation of any of our inputs by; default is 72.
 
 EXAMPLE JSON REQUEST
 --------------------

doc/lightning-unreserveinputs.7.md

@@ -4,7 +4,7 @@ lightning-unreserveinputs -- Release reserved UTXOs
 SYNOPSIS
 --------
 
-**unreserveinputs** *psbt*
+**unreserveinputs** *psbt* [*reserve*]
 
 DESCRIPTION
 -----------
@@ -15,6 +15,9 @@ lightning-reserveinputs(7).
 
 The inputs to unreserve are the inputs specified in the passed-in *psbt*.
 
+If *reserve* is specified, it is the number of blocks to decrease
+reservation by; default is 72.
+
 RETURN VALUE
 ------------
 

doc/lightning-utxopsbt.7.md

@@ -23,6 +23,11 @@ the resulting transaction plus *startweight* at the given *feerate*,
 with at least *satoshi* left over (unless *satoshi* is **all**, which
 is equivalent to setting it to zero).
 
+*reserve* is either boolean or a number: if *true* or a non-zero
+number then *reserveinputs* is called (successfully, with
+*exclusive* true) on the returned PSBT for this number of blocks (or
+72 blocks if *reserve* is simply *true*).
+
 Unless *reservedok* is set to true (default is false) it will also fail
 if any of the *utxos* are already reserved.
 
@@ -47,8 +52,8 @@ which is available.  This could be zero, or dust.  If *satoshi* was "all",
 then *excess_msat* is the entire amount once fees are subtracted
 for the weights of the inputs and *startweight*.
 
-If *reserve* was true, then a *reservations* array is returned,
-exactly like *reserveinputs*.
+If *reserve* was *true* or a non-zero number, then a *reservations*
+array is returned, exactly like *reserveinputs*.
 
 If *excess_as_change* is true and the excess is enough to cover
 an additional output above the `dust_limit`, then an output is

plugins/spender/multifundchannel.c

@@ -205,6 +205,7 @@ mfc_cleanup_psbt(struct command *cmd,
 	}
 
 	json_add_psbt(req->js, "psbt", take(pruned_psbt));
+	json_add_u32(req->js, "reserve", 2016);
 	send_outreq(cmd->plugin, req);
 }
 
@@ -651,6 +652,9 @@ after_signpsbt(struct command *cmd,
 				    &mfc_forward_error,
 				    mfc);
 	json_add_psbt(req->js, "psbt", mfc->psbt);
+	/* We already reserved inputs by 2 weeks, we don't need
+	 * another 72 blocks. */
+	json_add_u32(req->js, "reserve", 0);
 	return send_outreq(mfc->cmd->plugin, req);
 }
 
@@ -1405,8 +1409,14 @@ perform_fundpsbt(struct multifundchannel_command *mfc)
 		json_add_u32(req->js, "minconf", mfc->minconf);
 	}
 
-	/* The entire point is to reserve the inputs.  */
-	json_add_bool(req->js, "reserve", true);
+	/* The entire point is to reserve the inputs. */
+	/*  BOLT #2:
+	 * The sender:
+	 *...
+	 *     - SHOULD ensure the funding transaction confirms in the next 2016
+	 *       blocks.
+	 */
+	json_add_u32(req->js, "reserve", 2016);
 	/* How much do we need to reserve?  */
 	if (has_all(mfc))
 		json_add_string(req->js, "satoshi", "all");

tests/test_connection.py

@@ -246,6 +246,40 @@ def test_second_channel(node_factory):
     l1.fundchannel(l3, 10**6)
 
 
+def test_channel_abandon(node_factory, bitcoind):
+    """Our open tx isn't mined, we doublespend it away"""
+    l1, l2 = node_factory.get_nodes(2)
+
+    SATS = 10**6
+
+    # Add some for fees
+    l1.fundwallet(SATS + 10000)
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    l1.rpc.fundchannel(l2.info['id'], SATS, feerate='1875perkw')
+
+    opening_utxo = only_one([o for o in l1.rpc.listfunds()['outputs'] if o['reserved']])
+    psbt = l1.rpc.utxopsbt(0, "253perkw", 0, [opening_utxo['txid'] + ':' + str(opening_utxo['output'])], reserve=False, reservedok=True)['psbt']
+
+    # We expect a reservation for 2016 blocks; unreserve it.
+    reservations = only_one(l1.rpc.unreserveinputs(psbt, reserve=2015)['reservations'])
+    assert reservations['reserved']
+    assert reservations['reserved_to_block'] == bitcoind.rpc.getblockchaininfo()['blocks'] + 1
+
+    assert only_one(l1.rpc.unreserveinputs(psbt, reserve=1)['reservations'])['reserved'] is False
+
+    # Now it's unreserved, we can doublespend it (as long as we exceed
+    # previous fee to RBF!).
+    withdraw = l1.rpc.withdraw(l1.rpc.newaddr()['bech32'], "all")
+
+    assert bitcoind.rpc.decoderawtransaction(withdraw['tx'])['vout'][0]['value'] > SATS / 10**8
+    bitcoind.generate_block(1, wait_for_mempool=withdraw['txid'])
+
+    # FIXME: lightningd should notice channel will never now open!
+    print(l1.rpc.listpeers())
+    assert (only_one(only_one(l1.rpc.listpeers()['peers'])['channels'])['state']
+            == 'CHANNELD_AWAITING_LOCKIN')
+
+
 @pytest.mark.developer
 @pytest.mark.openchannel('v1')
 @pytest.mark.openchannel('v2')

tests/test_misc.py

@@ -634,6 +634,7 @@ def dont_spend_outputs(n, txid):
     for out in l1.rpc.listfunds()['outputs']:
         if out['reserved']:
             inputs += [{'txid': out['txid'], 'vout': out['output']}]
+            assert out['reserved_to_block'] > bitcoind.rpc.getblockchaininfo()['blocks']
     l1.rpc.unreserveinputs(bitcoind.rpc.createpsbt(inputs, []))
 
     # Test withdrawal to self.