ElementsProject · rustyrussell · May 3, 2021 · Apr 19, 2021 · Apr 20, 2021 · Apr 20, 2021
diff --git a/common/amount.c b/common/amount.c
@@ -325,10 +325,10 @@ WARN_UNUSED_RESULT bool amount_msat_add_sat(struct amount_msat *val,
 }
 
 WARN_UNUSED_RESULT bool amount_msat_scale(struct amount_msat *val,
-					  struct amount_msat sat,
+					  struct amount_msat msat,
 					  double scale)
 {
-	double scaled = sat.millisatoshis * scale;
+	double scaled = msat.millisatoshis * scale;
 
 	/* If mantissa is < 64 bits, a naive "if (scaled >
 	 * UINT64_MAX)" doesn't work.  Stick to powers of 2. */
@@ -338,6 +338,20 @@ WARN_UNUSED_RESULT bool amount_msat_scale(struct amount_msat *val,
 	return true;
 }
 
+WARN_UNUSED_RESULT bool amount_sat_scale(struct amount_sat *val,
+					 struct amount_sat sat,
+					 double scale)
+{
+	double scaled = sat.satoshis * scale;
+
+	/* If mantissa is < 64 bits, a naive "if (scaled >
+	 * UINT64_MAX)" doesn't work.  Stick to powers of 2. */
+	if (scaled >= (double)((u64)1 << 63) * 2)
+		return false;
+	val->satoshis = scaled;
+	return true;
+}
+
 bool amount_sat_eq(struct amount_sat a, struct amount_sat b)
 {
 	return a.satoshis == b.satoshis;

diff --git a/common/amount.h b/common/amount.h
@@ -83,6 +83,9 @@ WARN_UNUSED_RESULT bool amount_sat_sub_msat(struct amount_msat *val,
 WARN_UNUSED_RESULT bool amount_msat_scale(struct amount_msat *val,
 					  struct amount_msat msat,
 					  double scale);
+WARN_UNUSED_RESULT bool amount_sat_scale(struct amount_sat *val,
+					 struct amount_sat sat,
+					 double scale);
 
 struct amount_msat amount_msat_div(struct amount_msat msat, u64 div);
 struct amount_sat amount_sat_div(struct amount_sat sat, u64 div);

diff --git a/common/psbt_open.c b/common/psbt_open.c
@@ -481,3 +481,13 @@ bool psbt_input_is_ours(const struct wally_psbt_input *input)
 					  PSBT_TYPE_INPUT_MARKER, &unused);
 	return !(!result);
 }
+
+bool psbt_has_our_input(const struct wally_psbt *psbt)
+{
+	for (size_t i = 0; i < psbt->num_inputs; i++) {
+		if (psbt_input_is_ours(&psbt->inputs[i]))
+			return true;
+	}
+
+	return false;
+}
diff --git a/common/psbt_open.h b/common/psbt_open.h
@@ -174,4 +174,8 @@ void psbt_input_mark_ours(const tal_t *ctx,
  */
 bool psbt_input_is_ours(const struct wally_psbt_input *input);
 
+/* psbt_has_our_input  - Returns true if this psbt contains
+ * 			 any input that is ours
+ */
+bool psbt_has_our_input(const struct wally_psbt *psbt);
 #endif /* LIGHTNING_COMMON_PSBT_OPEN_H */
@@ -864,8 +864,7 @@ def has_funds_on_addr(addr):
                 txnum = i
 
         scid = "{}x{}x{}".format(self.bitcoin.rpc.getblockcount(),
-                                 txnum,
-                                 get_tx_p2wsh_outnum(self.bitcoin, res['tx'], amount))
+                                 txnum, res['outnum'])
 
         if wait_for_active:
             self.wait_channel_active(scid)

diff --git a/contrib/startup_regtest.sh b/contrib/startup_regtest.sh
@@ -92,8 +92,16 @@ start_nodes() {
 
 		# If we've configured to use developer, add dev options
 		if $LIGHTNINGD --help | grep -q dev-fast-gossip; then
-			echo "dev-fast-gossip" >> "/tmp/l$i-$network/config"
-			echo "dev-bitcoind-poll=5" >> "/tmp/l$i-$network/config"
+			cat <<- EOF >> "/tmp/l$i-$network/config"
+			dev-fast-gossip
+			dev-bitcoind-poll=5
+			experimental-dual-fund
+			funder-policy=match
+			funder-policy-mod=1000
+			funder-min-their-funding=10000
+			funder-per-channel-max=100000
+			funder-fuzz-percent=0
+			EOF
 		fi
 
 

diff --git a/doc/PLUGINS.md b/doc/PLUGINS.md
@@ -1034,6 +1034,7 @@ the v2 protocol, and it has passed basic sanity checks:
     "max_accepted_htlcs": 483,
     "channel_flags": 1
     "locktime": 2453,
+    "channel_max_msat": "16777215000msat"
   }
 }
 ```
@@ -1156,7 +1157,8 @@ requests an RBF for a channel funding transaction.
     "funding_feerate_per_kw": 7500,
     "feerate_our_max": 10000,
     "feerate_our_min": 253,
-    "locktime": 2453,
+    "channel_max_msat": "16777215000msat",
+    "locktime": 2453
   }
 }
 ```

diff --git a/lightningd/dual_open_control.c b/lightningd/dual_open_control.c
@@ -183,6 +183,9 @@ struct rbf_channel_payload {
 	/* General info */
 	u32 feerate_our_max;
 	u32 feerate_our_min;
+	/* What's the maximum amount of funding
+	 * this channel can hold */
+	struct amount_sat channel_max;
 
 	/* Returned from hook */
 	struct amount_sat our_funding;
@@ -206,6 +209,8 @@ rbf_channel_hook_serialize(struct rbf_channel_payload *payload,
 		     payload->feerate_our_min);
 	json_add_num(stream, "funding_feerate_per_kw",
 		     payload->funding_feerate_per_kw);
+	json_add_amount_sat_only(stream, "channel_max_msat",
+				 payload->channel_max);
 	json_object_end(stream);
 }
 
@@ -241,6 +246,9 @@ struct openchannel2_payload {
 	u8 channel_flags;
 	u32 locktime;
 	u8 *shutdown_scriptpubkey;
+	/* What's the maximum amount of funding
+	 * this channel can hold */
+	struct amount_sat channel_max;
 
 	struct amount_sat accepter_funding;
 	struct wally_psbt *psbt;
@@ -278,6 +286,8 @@ openchannel2_hook_serialize(struct openchannel2_payload *payload,
 	if (tal_bytelen(payload->shutdown_scriptpubkey) != 0)
 		json_add_hex_talarr(stream, "shutdown_scriptpubkey",
 				    payload->shutdown_scriptpubkey);
+	json_add_amount_sat_only(stream, "channel_max_msat",
+				 payload->channel_max);
 	json_object_end(stream);
 }
 
@@ -617,6 +627,10 @@ rbf_channel_hook_deserialize(struct rbf_channel_payload *payload,
 				 "our_funding_msat", &payload->our_funding))
 		fatal("Plugin failed to supply our_funding_msat field");
 
+	if (payload->psbt
+	    && amount_sat_eq(payload->our_funding, AMOUNT_SAT(0)))
+		fatal("Plugin failed to supply our_funding_msat field");
+
 	if (!payload->psbt &&
 		!amount_sat_eq(payload->our_funding, AMOUNT_SAT(0))) {
 
@@ -777,8 +791,12 @@ openchannel2_hook_deserialize(struct openchannel2_payload *payload,
 				 &payload->accepter_funding))
 		fatal("Plugin failed to supply our_funding_msat field");
 
-	if (!payload->psbt &&
-		!amount_sat_eq(payload->accepter_funding, AMOUNT_SAT(0))) {
+	if (payload->psbt
+	    && amount_sat_eq(payload->accepter_funding, AMOUNT_SAT(0)))
+		fatal("Plugin failed to supply our_funding_msat field");
+
+	if (!payload->psbt
+	    && !amount_sat_eq(payload->accepter_funding, AMOUNT_SAT(0))) {
 		/* Gotta give a PSBT if you set the accepter_funding amount */
 		/* Let dualopend know we've failed */
 		payload->err_msg = "Client error. Unable to continue";
@@ -1636,6 +1654,12 @@ static void rbf_got_offer(struct subd *dualopend, const u8 *msg)
 	/* No error message known (yet) */
 	payload->err_msg = NULL;
 
+	payload->channel_max = chainparams->max_funding;
+	if (feature_negotiated(dualopend->ld->our_features,
+			       channel->peer->their_features,
+			       OPT_LARGE_CHANNELS))
+		payload->channel_max = AMOUNT_SAT(UINT_MAX);
+
 	tal_add_destructor2(dualopend, rbf_channel_remove_dualopend, payload);
 	plugin_hook_call_rbf_channel(dualopend->ld, payload);
 }
@@ -1695,6 +1719,12 @@ static void accepter_got_offer(struct subd *dualopend,
 	payload->feerate_our_min = feerate_min(dualopend->ld, NULL);
 	payload->feerate_our_max = feerate_max(dualopend->ld, NULL);
 
+	payload->channel_max = chainparams->max_funding;
+	if (feature_negotiated(dualopend->ld->our_features,
+			       channel->peer->their_features,
+			       OPT_LARGE_CHANNELS))
+		payload->channel_max = AMOUNT_SAT(UINT64_MAX);
+
 	tal_add_destructor2(dualopend, openchannel2_remove_dualopend, payload);
 	plugin_hook_call_openchannel2(dualopend->ld, payload);
 }

diff --git a/openingd/dualopend.c b/openingd/dualopend.c
@@ -1896,8 +1896,8 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 {
 	struct bitcoin_blkid chain_hash;
 	struct tlv_opening_tlvs *open_tlv;
+	struct channel_id cid, full_cid;
 	char *err_reason;
-	struct channel_id tmp_chan_id;
 	u8 *msg;
 	struct amount_sat total;
 	enum dualopend_wire msg_type;
@@ -1907,7 +1907,7 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 	open_tlv = tlv_opening_tlvs_new(tmpctx);
 
 	if (!fromwire_open_channel2(oc2_msg, &chain_hash,
-				    &state->channel_id, /* Temporary! */
+				    &cid,
 				    &tx_state->feerate_per_kw_funding,
 				    &state->feerate_per_kw_commitment,
 				    &tx_state->opener_funding,
@@ -1939,21 +1939,15 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 	 * `open_channel2`), a temporary `channel_id` should be found
 	 * by using a zeroed out basepoint for the unknown peer.
 	 */
-	derive_tmp_channel_id(&tmp_chan_id,
+	derive_tmp_channel_id(&state->channel_id, /* Temporary! */
 			      &state->their_points.revocation);
-	if (!channel_id_eq(&state->channel_id, &tmp_chan_id))
+	if (!channel_id_eq(&state->channel_id, &cid))
 		negotiation_failed(state, "open_channel2 channel_id incorrect."
 				   " Expected %s, received %s",
 				   type_to_string(tmpctx, struct channel_id,
-						  &tmp_chan_id),
+						  &state->channel_id),
 				   type_to_string(tmpctx, struct channel_id,
-						  &state->channel_id));
-
-	/* Everything's ok. Let's figure out the actual channel_id now */
-	derive_channel_id_v2(&state->channel_id,
-			     &state->our_points.revocation,
-			     &state->their_points.revocation);
-
+						  &cid));
 
 	/* Save feerate on the state as well */
 	state->feerate_per_kw_funding = tx_state->feerate_per_kw_funding;
@@ -1990,8 +1984,12 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 		return;
 	}
 
+	/* We send the 'real' channel id over to lightningd */
+	derive_channel_id_v2(&full_cid,
+			     &state->our_points.revocation,
+			     &state->their_points.revocation);
 	msg = towire_dualopend_got_offer(NULL,
-					 &state->channel_id,
+					 &full_cid,
 					 tx_state->opener_funding,
 					 tx_state->remoteconf.dust_limit,
 					 tx_state->remoteconf.max_htlc_value_in_flight,
@@ -2010,7 +2008,6 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 	if ((msg_type = fromwire_peektype(msg)) == WIRE_DUALOPEND_FAIL) {
 		if (!fromwire_dualopend_fail(msg, msg, &err_reason))
 			master_badmsg(msg_type, msg);
-
 		open_err_warn(state, "%s", err_reason);
 		return;
 	}
@@ -2024,6 +2021,9 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 	if (!tx_state->psbt)
 		tx_state->psbt = create_psbt(tx_state, 0, 0,
 					     tx_state->tx_locktime);
+	else
+		/* Locktimes must match! */
+		tx_state->psbt->tx->locktime = tx_state->tx_locktime;
 
 	/* Check that total funding doesn't overflow */
 	if (!amount_sat_add(&total, tx_state->opener_funding,
@@ -2105,6 +2105,11 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 				     &state->first_per_commitment_point[LOCAL],
 				     a_tlv);
 
+	/* Everything's ok. Let's figure out the actual channel_id now */
+	derive_channel_id_v2(&state->channel_id,
+			     &state->our_points.revocation,
+			     &state->their_points.revocation);
+
 	sync_crypto_write(state->pps, msg);
 	peer_billboard(false, "channel open: accept sent, waiting for reply");
 
@@ -2479,6 +2484,23 @@ static void opener_start(struct state *state, u8 *msg)
 		open_err_fatal(state,  "Parsing accept_channel2 %s",
 			       tal_hex(msg, msg));
 
+	if (!channel_id_eq(&cid, &state->channel_id)) {
+		struct channel_id future_chan_id;
+		/* FIXME: v0.10.0 actually replied with the complete channel id here,
+		 * so we need to accept it for now */
+		derive_channel_id_v2(&future_chan_id,
+				     &state->our_points.revocation,
+				     &state->their_points.revocation);
+		if (!channel_id_eq(&cid, &future_chan_id)) {
+			peer_failed_err(state->pps, &cid,
+					"accept_channel2 ids don't match: "
+					"expected %s, got %s",
+					type_to_string(msg, struct channel_id,
+						       &state->channel_id),
+					type_to_string(msg, struct channel_id, &cid));
+		}
+	}
+
 	if (a_tlv->option_upfront_shutdown_script) {
 		state->upfront_shutdown_script[REMOTE]
 			= tal_steal(state,
@@ -2492,14 +2514,6 @@ static void opener_start(struct state *state, u8 *msg)
 			     &state->our_points.revocation,
 			     &state->their_points.revocation);
 
-	if (!channel_id_eq(&cid, &state->channel_id))
-		peer_failed_err(state->pps, &cid,
-				"accept_channel2 ids don't match: "
-				"expected %s, got %s",
-				type_to_string(msg, struct channel_id,
-					       &state->channel_id),
-				type_to_string(msg, struct channel_id, &cid));
-
 	/* Check that total funding doesn't overflow */
 	if (!amount_sat_add(&total, tx_state->opener_funding,
 			    tx_state->accepter_funding))

diff --git a/plugins/.gitignore b/plugins/.gitignore
@@ -1,5 +1,6 @@
 autoclean
 bcli
+funder
 pay
 spenderp
 multifundchannel

diff --git a/plugins/Makefile b/plugins/Makefile
@@ -43,10 +43,18 @@ PLUGIN_SPENDER_HEADER :=			\
 	plugins/spender/openchannel.h
 PLUGIN_SPENDER_OBJS := $(PLUGIN_SPENDER_SRC:.c=.o)
 
+PLUGIN_FUNDER_SRC :=				\
+	plugins/funder.c			\
+	plugins/funder_policy.c
+PLUGIN_FUNDER_HEADER :=				\
+	plugins/funder_policy.h
+PLUGIN_FUNDER_OBJS := $(PLUGIN_FUNDER_SRC:.c=.o)
+
 PLUGIN_ALL_SRC :=				\
 	$(PLUGIN_AUTOCLEAN_SRC)			\
 	$(PLUGIN_BCLI_SRC)			\
 	$(PLUGIN_FETCHINVOICE_SRC)		\
+	$(PLUGIN_FUNDER_SRC)			\
 	$(PLUGIN_KEYSEND_SRC)			\
 	$(PLUGIN_TXPREPARE_SRC)			\
 	$(PLUGIN_LIB_SRC)			\
@@ -57,6 +65,7 @@ PLUGIN_ALL_SRC :=				\
 
 PLUGIN_ALL_HEADER :=				\
 	$(PLUGIN_LIB_HEADER)			\
+	$(PLUGIN_FUNDER_HEADER)			\
 	$(PLUGIN_PAY_LIB_HEADER)		\
 	$(PLUGIN_OFFERS_HEADER)			\
 	$(PLUGIN_SPENDER_HEADER)
@@ -66,6 +75,7 @@ PLUGINS :=					\
 	plugins/autoclean			\
 	plugins/bcli				\
 	plugins/fetchinvoice			\
+	plugins/funder				\
 	plugins/keysend				\
 	plugins/offers				\
 	plugins/pay				\
@@ -106,6 +116,7 @@ PLUGIN_COMMON_OBJS :=				\
 	common/memleak.o			\
 	common/node_id.o			\
 	common/param.o				\
+	common/psbt_open.o			\
 	common/pseudorand.o			\
 	common/random_select.o			\
 	common/setup.o				\
@@ -137,9 +148,13 @@ plugins/offers: bitcoin/chainparams.o $(PLUGIN_OFFERS_OBJS) $(PLUGIN_LIB_OBJS) $
 
 plugins/fetchinvoice: bitcoin/chainparams.o $(PLUGIN_FETCHINVOICE_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_COMMON_OBJS) common/bolt12.o common/bolt12_merkle.o common/iso4217.o $(WIRE_OBJS) bitcoin/block.o common/channel_id.o bitcoin/preimage.o $(JSMN_OBJS) $(CCAN_OBJS) common/gossmap.o common/fp16.o common/dijkstra.o common/route.o common/blindedpath.o common/hmac.o common/blinding.o
 
+plugins/funder: bitcoin/chainparams.o bitcoin/psbt.o common/psbt_open.o $(PLUGIN_FUNDER_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)
+
 $(PLUGIN_ALL_OBJS): $(PLUGIN_LIB_HEADER)
 
 # Generated from PLUGINS definition in plugins/Makefile
 ALL_C_HEADERS += plugins/list_of_builtin_plugins_gen.h
 plugins/list_of_builtin_plugins_gen.h: plugins/Makefile Makefile
 	@$(call VERBOSE,GEN $@,echo "static const char *list_of_builtin_plugins[] = { $(foreach d,$(notdir $(PLUGINS)),\"$d\",) NULL };" > $@)
+
+include plugins/test/Makefile