lightningd: simple wallet support.

This allows us to add funds via the P2SH-wrapped Segwit Transactions.

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

bitcoin/script.c

@@ -322,6 +322,17 @@ u8 *scriptpubkey_p2wpkh(const tal_t *ctx, const struct pubkey *key)
 	return script;
 }
 
+u8 *scriptpubkey_p2wpkh_derkey(const tal_t *ctx, const u8 der[33])
+{
+	u8 *script = tal_arr(ctx, u8, 0);
+	struct ripemd160 h;
+
+	add_op(&script, OP_0);
+	hash160(&h, der, PUBKEY_DER_LEN);
+	add_push_bytes(&script, &h, sizeof(h));
+	return script;
+}
+
 /* Create a witness which spends the 2of2. */
 u8 **bitcoin_witness_2of2(const tal_t *ctx,
 			  const secp256k1_ecdsa_signature *sig1,

bitcoin/script.h

@@ -78,6 +78,9 @@ u8 *scriptpubkey_p2wsh(const tal_t *ctx, const u8 *witnessscript);
 /* Create an output script for a 20-byte witness program. */
 u8 *scriptpubkey_p2wpkh(const tal_t *ctx, const struct pubkey *key);
 
+/* Same as above, but compressed key is already DER-encoded. */
+u8 *scriptpubkey_p2wpkh_derkey(const tal_t *ctx, const u8 der[33]);
+
 /* Create a witness which spends the 2of2. */
 u8 **bitcoin_witness_2of2(const tal_t *ctx,
 			  const secp256k1_ecdsa_signature *sig1,

daemon/test/scripts/helpers.sh

@@ -308,6 +308,12 @@ all_ok()
     exit 0
 }
 
+# If result is in quotes, those are stripped.  Spaces in quotes not handled
+get_field()
+{
+    tr -s '\012\011" ' ' ' | sed 's/.* '$1' : \([^, }]*\).*/\1/'
+}    
+
 # If result is in quotes, those are stripped.  Spaces in quotes not handled
 get_info_field()
 {

lightningd/Makefile

@@ -47,6 +47,7 @@ LIGHTNINGD_LIB_OBJS := $(LIGHTNINGD_LIB_SRC:.c=.o)
 LIGHTNINGD_LIB_HEADERS := $(LIGHTNINGD_LIB_SRC:.c=.h)
 
 LIGHTNINGD_SRC :=				\
+	lightningd/build_utxos.c		\
 	lightningd/gossip_control.c		\
 	lightningd/hsm_control.c		\
 	lightningd/lightningd.c			\
@@ -60,6 +61,7 @@ LIGHTNINGD_JSMN_HEADERS := daemon/jsmn/jsmn.h
 
 # We accumulate all lightningd/ headers in these three:
 LIGHTNINGD_HEADERS_NOGEN =			\
+	lightningd/build_utxos.h		\
 	lightningd/gossip_control.h		\
 	lightningd/hsm_control.h		\
 	lightningd/lightningd.h			\

lightningd/build_utxos.c

@@ -0,0 +1,238 @@
+#include <bitcoin/base58.h>
+#include <bitcoin/script.h>
+#include <ccan/structeq/structeq.h>
+#include <daemon/jsonrpc.h>
+#include <lightningd/build_utxos.h>
+#include <lightningd/lightningd.h>
+#include <utils.h>
+#include <wally_bip32.h>
+
+struct tracked_utxo {
+	struct list_node list;
+
+	/* Currently being used for a connection. */
+	bool reserved;
+
+	struct utxo utxo;
+};
+
+static void json_newaddr(struct command *cmd,
+			 const char *buffer, const jsmntok_t *params)
+{
+	struct json_result *response = new_json_result(cmd);
+	struct lightningd *ld = ld_from_dstate(cmd->dstate);
+	struct ext_key ext;
+	struct sha256 h;
+	struct ripemd160 p2sh;
+	struct pubkey pubkey;
+	u8 *redeemscript;
+
+	if (ld->bip32_max_index == BIP32_INITIAL_HARDENED_CHILD) {
+		command_fail(cmd, "Keys exhausted ");
+		return;
+	}
+
+	if (bip32_key_from_parent(ld->bip32_base, ld->bip32_max_index,
+				  BIP32_FLAG_KEY_PUBLIC, &ext) != WALLY_OK) {
+		command_fail(cmd, "Keys generation failure");
+		return;
+	}
+
+	if (!secp256k1_ec_pubkey_parse(secp256k1_ctx, &pubkey.pubkey,
+				       ext.pub_key, sizeof(ext.pub_key))) {
+		command_fail(cmd, "Key parsing failure");
+		return;
+	}
+
+	redeemscript = bitcoin_redeem_p2wpkh(cmd, &pubkey);
+	sha256(&h, redeemscript, tal_count(redeemscript));
+	ripemd160(&p2sh, h.u.u8, sizeof(h));
+
+	ld->bip32_max_index++;
+
+	json_object_start(response, NULL);
+	json_add_string(response, "address",
+			p2sh_to_base58(cmd, cmd->dstate->testnet, &p2sh));
+	json_object_end(response);
+	command_success(cmd, response);
+}
+
+static const struct json_command newaddr_command = {
+	"newaddr",
+	json_newaddr,
+	"Get a new address to fund a channel",
+	"Returns {address} a p2sh address"
+};
+AUTODATA(json_command, &newaddr_command);
+
+/* FIXME: This is very slow with lots of inputs! */
+static bool can_spend(struct lightningd *ld, const u8 *script,
+		      u32 *index, bool *output_is_p2sh)
+{
+	struct ext_key ext;
+	u32 i;
+
+	/* If not one of these, can't be for us. */
+	if (is_p2sh(script))
+		*output_is_p2sh = true;
+	else if (is_p2wpkh(script))
+		*output_is_p2sh = false;
+	else
+		return false;
+
+	for (i = 0; i < ld->bip32_max_index; i++) {
+		u8 *s;
+
+		if (bip32_key_from_parent(ld->bip32_base, i,
+					  BIP32_FLAG_KEY_PUBLIC, &ext)
+		    != WALLY_OK) {
+			abort();
+		}
+		s = scriptpubkey_p2wpkh_derkey(ld, ext.pub_key);
+		if (*output_is_p2sh) {
+			u8 *p2sh = scriptpubkey_p2sh(ld, s);
+			tal_free(s);
+			s = p2sh;
+		}
+		if (scripteq(s, script)) {
+			tal_free(s);
+			*index = i;
+			return true;
+		}
+		tal_free(s);
+	}
+	return false;
+}
+
+static void json_addfunds(struct command *cmd,
+			  const char *buffer, const jsmntok_t *params)
+{
+	struct lightningd *ld = ld_from_dstate(cmd->dstate);
+	struct json_result *response = new_json_result(cmd);
+	jsmntok_t *txtok;
+	struct bitcoin_tx *tx;
+	int output;
+	size_t txhexlen, num_utxos = 0;
+	u64 total_satoshi = 0;
+
+	if (!json_get_params(buffer, params, "tx", &txtok, NULL)) {
+		command_fail(cmd, "Need tx sending to address from newaddr");
+		return;
+	}
+
+	txhexlen = txtok->end - txtok->start;
+	tx = bitcoin_tx_from_hex(cmd, buffer + txtok->start, txhexlen);
+	if (!tx) {
+		command_fail(cmd, "'%.*s' is not a valid transaction",
+			     txtok->end - txtok->start,
+			     buffer + txtok->start);
+		return;
+	}
+
+	/* Find an output we know how to spend. */
+	for (output = 0; output < tal_count(tx->output); output++) {
+		struct tracked_utxo *utxo;
+		u32 index;
+		bool is_p2sh;
+
+		if (!can_spend(ld, tx->output[output].script, &index, &is_p2sh))
+			continue;
+
+		utxo = tal(ld, struct tracked_utxo);
+		utxo->utxo.keyindex = index;
+		utxo->utxo.is_p2sh = is_p2sh;
+		utxo->utxo.amount = tx->output[output].amount;
+		bitcoin_txid(tx, &utxo->utxo.txid);
+		utxo->utxo.outnum = output;
+		utxo->reserved = false;
+		list_add_tail(&ld->utxos, &utxo->list);
+		total_satoshi += utxo->utxo.amount;
+		num_utxos++;
+	}
+
+	if (!num_utxos) {
+		command_fail(cmd, "No usable outputs");
+		return;
+	}
+
+	json_object_start(response, NULL);
+	json_add_num(response, "outputs", num_utxos);
+	json_add_u64(response, "satoshis", total_satoshi);
+	json_object_end(response);
+	command_success(cmd, response);
+}
+
+static const struct json_command addfunds_command = {
+	"addfunds",
+	json_addfunds,
+	"Add funds for lightningd to spend to create channels, using {tx}",
+	"Returns how many {outputs} it can use and total {satoshis}"
+};
+AUTODATA(json_command, &addfunds_command);
+
+static void unreserve_utxo(struct lightningd *ld, const struct utxo *unres)
+{
+	struct tracked_utxo *utxo;
+
+	list_for_each(&ld->utxos, utxo, list) {
+		if (unres->outnum != utxo->utxo.outnum
+		    || !structeq(&unres->txid, &utxo->utxo.txid))
+			continue;
+		assert(utxo->reserved);
+		assert(unres->amount == utxo->utxo.amount);
+		assert(unres->keyindex == utxo->utxo.keyindex);
+		assert(unres->is_p2sh == utxo->utxo.is_p2sh);
+		utxo->reserved = false;
+		return;
+	}
+	abort();
+}
+
+struct utxo *build_utxos(const tal_t *ctx,
+			 struct lightningd *ld, u64 satoshi_out,
+			 u32 feerate_per_kw, u64 dust_limit,
+			 u64 *change_amount, u32 *change_keyindex)
+{
+	size_t i = 0;
+	struct utxo *utxos = tal_arr(ctx, struct utxo, 0);
+	struct tracked_utxo *utxo;
+	/* We assume two outputs for the weight. */
+	u64 satoshi_in = 0, weight = (4 + (8 + 22) * 2 + 4) * 4;
+
+	list_for_each(&ld->utxos, utxo, list) {
+		u64 fee;
+
+		if (utxo->reserved)
+			continue;
+
+		tal_resize(&utxos, i+1);
+		utxos[i] = utxo->utxo;
+		utxo->reserved = true;
+
+		/* Add this input's weight. */
+		weight += (32 + 4 + 4) * 4;
+		if (utxos[i].is_p2sh)
+			weight += 22 * 4;
+
+		satoshi_in += utxos[i].amount;
+
+		fee = weight * feerate_per_kw / 1000;
+		if (satoshi_in >= fee + satoshi_out) {
+			/* We simply eliminate change if it's dust. */
+			*change_amount = satoshi_in - (fee + satoshi_out);
+			if (*change_amount < dust_limit)
+				*change_amount = 0;
+			else
+				*change_keyindex = ld->bip32_max_index++;
+
+			return utxos;
+		}
+		i++;
+	}
+
+	/* Failed, unmark them all. */
+	for (i = 0; i < tal_count(utxos); i++)
+		unreserve_utxo(ld, &utxos[i]);
+
+	return tal_free(utxos);
+}

lightningd/build_utxos.h

@@ -0,0 +1,14 @@
+#ifndef LIGHTNING_LIGHTNINGD_BUILD_UTXOS_H
+#define LIGHTNING_LIGHTNINGD_BUILD_UTXOS_H
+#include "config.h"
+#include <lightningd/lightningd.h>
+#include <lightningd/utxo.h>
+
+/* Reserves UTXOs to build tx which pays this amount; returns NULL if
+ * impossible.  *change_amount 0 if no change needed. */
+struct utxo *build_utxos(const tal_t *ctx,
+			 struct lightningd *ld, u64 satoshi_out,
+			 u32 feerate_per_kw, u64 dust_limit,
+			 u64 *change_amount, u32 *change_keyindex);
+
+#endif /* LIGHTNING_LIGHTNINGD_BUILD_UTXOS_H */

lightningd/lightningd.c

@@ -71,6 +71,8 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	struct lightningd *ld = tal(ctx, struct lightningd);
 
 	list_head_init(&ld->peers);
+	ld->bip32_max_index = 0;
+	list_head_init(&ld->utxos);
 	ld->dstate.log_book = new_log_book(&ld->dstate, 20*1024*1024,LOG_INFORM);
 	ld->log = ld->dstate.base_log = new_log(&ld->dstate,
 						ld->dstate.log_book,

lightningd/lightningd.h

@@ -31,8 +31,12 @@ struct lightningd {
 	/* All peers we're tracking. */
 	struct list_head peers;
 
-	/* Public base for bip32 keys. */
+	/* Public base for bip32 keys, and max we've ever used. */
 	struct ext_key *bip32_base;
+	u32 bip32_max_index;
+
+	/* UTXOs we have available to spend. */
+	struct list_head utxos;
 };
 
 /* FIXME */

lightningd/opening/opening.c

@@ -45,7 +45,7 @@ struct secrets {
 };
 
 struct state {
-	struct crypto_state *cs;
+	struct crypto_state cs;
 	struct pubkey next_per_commit[NUM_SIDES];
 
 	/* Funding and feerate: set by opening peer. */
@@ -59,7 +59,7 @@ struct state {
 
 	/* Our shaseed for generating per-commitment-secrets. */
 	struct sha256 shaseed;
-	struct channel_config *localconf, *remoteconf, *minconf, *maxconf;
+	struct channel_config localconf, *remoteconf, minconf, maxconf;
 
 	struct channel *channel;
 };
@@ -242,25 +242,25 @@ static void open_channel(struct state *state, const struct points *ours)
 
 	msg = towire_open_channel(state, &tmpid,
 				  state->funding_satoshis, state->push_msat,
-				  state->localconf->dust_limit_satoshis,
+				  state->localconf.dust_limit_satoshis,
-				  state->localconf->max_htlc_value_in_flight_msat,
+				  state->localconf.max_htlc_value_in_flight_msat,
-				  state->localconf->channel_reserve_satoshis,
+				  state->localconf.channel_reserve_satoshis,
-				  state->localconf->htlc_minimum_msat,
+				  state->localconf.htlc_minimum_msat,
 				  state->feerate_per_kw,
-				  state->localconf->to_self_delay,
+				  state->localconf.to_self_delay,
-				  state->localconf->max_accepted_htlcs,
+				  state->localconf.max_accepted_htlcs,
 				  &ours->funding_pubkey,
 				  &ours->revocation_basepoint,
 				  &ours->payment_basepoint,
 				  &ours->delayed_payment_basepoint,
 				  &state->next_per_commit[LOCAL]);
-	if (!sync_crypto_write(state->cs, PEER_FD, msg))
+	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		status_failed(WIRE_OPENING_PEER_WRITE_FAILED,
 			      "Writing open_channel");
 
 	state->remoteconf = tal(state, struct channel_config);
 
-	msg = sync_crypto_read(state, state->cs, PEER_FD);
+	msg = sync_crypto_read(state, &state->cs, PEER_FD);
 	if (!msg)
 		status_failed(WIRE_OPENING_PEER_READ_FAILED,
 			      "Reading accept_channel");
@@ -301,7 +301,7 @@ static void open_channel(struct state *state, const struct points *ours)
 			      type_to_string(msg, struct channel_id, &tmpid2));
 
 	check_config_bounds(state->remoteconf,
-			    state->minconf, state->maxconf);
+			    &state->minconf, &state->maxconf);
 
 	/* Now, ask master create a transaction to pay those two addresses. */
 	msg = towire_opening_open_resp(state, &ours->funding_pubkey,
@@ -321,7 +321,7 @@ static void open_channel(struct state *state, const struct points *ours)
 				      state->funding_satoshis,
 				      state->push_msat,
 				      state->feerate_per_kw,
-				      state->localconf,
+				      &state->localconf,
 				      state->remoteconf,
 				      &ours->revocation_basepoint,
 				      &theirs.revocation_basepoint,
@@ -352,7 +352,7 @@ static void open_channel(struct state *state, const struct points *ours)
 				     &state->funding_txid.sha,
 				     state->funding_txout,
 				     &sig);
-	if (!sync_crypto_write(state->cs, PEER_FD, msg))
+	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		status_failed(WIRE_OPENING_PEER_WRITE_FAILED,
 			      "Writing funding_created");
 
@@ -364,7 +364,7 @@ static void open_channel(struct state *state, const struct points *ours)
 	 * commitment transaction, so they can broadcast it knowing they can
 	 * redeem their funds if they need to.
 	 */
-	msg = sync_crypto_read(state, state->cs, PEER_FD);
+	msg = sync_crypto_read(state, &state->cs, PEER_FD);
 	if (!msg)
 		status_failed(WIRE_OPENING_PEER_READ_FAILED,
 			      "Reading funding_signed");
@@ -403,7 +403,7 @@ static void open_channel(struct state *state, const struct points *ours)
 	msg = towire_opening_open_funding_resp(state,
 					       state->remoteconf,
 					       &sig,
-					       state->cs,
+					       &state->cs,
 					       &theirs.revocation_basepoint,
 					       &theirs.payment_basepoint,
 					       &theirs.delayed_payment_basepoint,
@@ -471,28 +471,28 @@ static void recv_channel(struct state *state, const struct points *ours,
 			      state->push_msat, state->funding_satoshis);
 
 	check_config_bounds(state->remoteconf,
-			    state->minconf, state->maxconf);
+			    &state->minconf, &state->maxconf);
 
 	msg = towire_accept_channel(state, &tmpid,
-				    state->localconf->dust_limit_satoshis,
+				    state->localconf.dust_limit_satoshis,
 				    state->localconf
-				      ->max_htlc_value_in_flight_msat,
+				      .max_htlc_value_in_flight_msat,
-				    state->localconf->channel_reserve_satoshis,
+				    state->localconf.channel_reserve_satoshis,
-				    state->localconf->htlc_minimum_msat,
+				    state->localconf.htlc_minimum_msat,
 				    state->feerate_per_kw,
-				    state->localconf->to_self_delay,
+				    state->localconf.to_self_delay,
-				    state->localconf->max_accepted_htlcs,
+				    state->localconf.max_accepted_htlcs,
 				    &ours->funding_pubkey,
 				    &ours->revocation_basepoint,
 				    &ours->payment_basepoint,
 				    &ours->delayed_payment_basepoint,
 				    &state->next_per_commit[REMOTE]);
 
-	if (!sync_crypto_write(state->cs, PEER_FD, msg))
+	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		status_failed(WIRE_OPENING_PEER_WRITE_FAILED,
 			      "Writing accept_channel");
 
-	msg = sync_crypto_read(state, state->cs, PEER_FD);
+	msg = sync_crypto_read(state, &state->cs, PEER_FD);
 	if (!msg)
 		status_failed(WIRE_OPENING_PEER_READ_FAILED,
 			      "Reading funding_created");
@@ -520,7 +520,7 @@ static void recv_channel(struct state *state, const struct points *ours,
 				      state->funding_satoshis,
 				      state->push_msat,
 				      state->feerate_per_kw,
-				      state->localconf,
+				      &state->localconf,
 				      state->remoteconf,
 				      &ours->revocation_basepoint,
 				      &theirs.revocation_basepoint,
@@ -565,7 +565,7 @@ static void recv_channel(struct state *state, const struct points *ours,
 				 tx);
 
 	msg = towire_funding_signed(state, &tmpid, &sig);
-	if (!sync_crypto_write(state->cs, PEER_FD, msg))
+	if (!sync_crypto_write(&state->cs, PEER_FD, msg))
 		status_failed(WIRE_OPENING_PEER_WRITE_FAILED,
 			      "Writing funding_signed");
 
@@ -574,7 +574,7 @@ static void recv_channel(struct state *state, const struct points *ours,
 					 state->funding_txout,
 					 state->remoteconf,
 					 &theirsig,
-					 state->cs,
+					 &state->cs,
 					 &theirs.funding_pubkey,
 					 &theirs.revocation_basepoint,
 					 &theirs.payment_basepoint,
@@ -609,12 +609,11 @@ int main(int argc, char *argv[])
 	if (!msg)
 		status_failed(WIRE_BAD_COMMAND, "%s", strerror(errno));
 
-	state->cs = tal(state, struct crypto_state);
 	if (!fromwire_opening_init(msg, NULL,
 				   &state->localconf,
 				   &state->minconf,
 				   &state->maxconf,
-				   state->cs,
+				   &state->cs,
 				   &seed))
 		status_failed(WIRE_BAD_COMMAND, "%s", strerror(errno));
 	tal_free(msg);

lightningd/test/test-basic

@@ -30,6 +30,14 @@ lcli1 getpeers info | $FGREP "Exchanging gossip"
 lcli1 getpeers | $FGREP '"owner" : "lightningd_gossip"'
 lcli2 getpeers | $FGREP '"owner" : "lightningd_gossip"'
 
+# Add some funds.
+set -x
+NEWADDR=`lcli1 newaddr | get_field address`
+FUND_INPUT_TXID=`$CLI sendtoaddress $NEWADDR 0.10000002`
+FUND_INPUT_TX=`$CLI getrawtransaction $FUND_INPUT_TXID`
+
+lcli1 addfunds $FUND_INPUT_TX | $FGREP '"satoshis" : 10000002'
+
 lcli1 stop
 lcli2 stop