wallet: Add scriptPubkey to struct utxo

In order to avoid having to ask the HSM for public keys to
their_unilateral/to_us outputs we just store the `scriptPubkey` with the UTXO,
which can then be converted to the P2WPKH address.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

common/utxo.c

@@ -31,6 +31,11 @@ struct utxo *fromwire_utxo(const tal_t *ctx, const u8 **ptr, size_t *max)
 	utxo->amount = fromwire_amount_sat(ptr, max);
 	utxo->keyindex = fromwire_u32(ptr, max);
 	utxo->is_p2sh = fromwire_bool(ptr, max);
+
+	/* No need to tell hsmd about the scriptPubkey, it has all the info to
+	 * derive it from the rest. */
+	utxo->scriptPubkey = NULL;
+
 	if (fromwire_bool(ptr, max)) {
 		utxo->close_info = tal(utxo, struct unilateral_close_info);
 		utxo->close_info->channel_id = fromwire_u64(ptr, max);

common/utxo.h

@@ -35,6 +35,9 @@ struct utxo {
 
 	/* NULL if not spent yet, otherwise, the block the spending transaction is in */
 	const u32 *spendheight;
+
+	/* The scriptPubkey if it is known */
+	u8 *scriptPubkey;
 };
 
 void towire_utxo(u8 **pptr, const struct utxo *utxo);

lightningd/onchain_control.c

@@ -272,6 +272,7 @@ static void onchain_add_utxo(struct channel *channel, const u8 *msg)
 	u->close_info->channel_id = channel->dbid;
 	u->close_info->peer_id = channel->peer->id;
 	u->spendheight = NULL;
+	u->scriptPubkey = NULL;
 
 	if (!fromwire_onchain_add_utxo(msg, &u->txid, &u->outnum,
 				       &u->close_info->commitment_point,

wallet/db.c

@@ -358,6 +358,7 @@ char *dbmigrations[] = {
     "ALTER TABLE payments ADD faildirection INTEGER;", /* erring_direction */
     /* Fix dangling peers with no channels. */
     "DELETE FROM peers WHERE id NOT IN (SELECT peer_id FROM channels);",
+    "ALTER TABLE outputs ADD scriptpubkey BLOB;",
     NULL,
 };
 

wallet/wallet.c

@@ -65,7 +65,7 @@ struct wallet *wallet_new(struct lightningd *ld,
 #define UTXO_FIELDS							\
 	"prev_out_tx, prev_out_index, value, type, status, keyindex, "	\
 	"channel_id, peer_id, commitment_point, confirmation_height, "	\
-	"spend_height"
+	"spend_height, scriptpubkey"
 
 /* We actually use the db constraints to uniquify, so OK if this fails. */
 bool wallet_add_utxo(struct wallet *w, struct utxo *utxo,
@@ -75,7 +75,7 @@ bool wallet_add_utxo(struct wallet *w, struct utxo *utxo,
 
 	stmt = db_prepare(w->db, "INSERT INTO outputs ("
 			  UTXO_FIELDS
-			  ") VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);");
+			  ") VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);");
 	sqlite3_bind_blob(stmt, 1, &utxo->txid, sizeof(utxo->txid), SQLITE_TRANSIENT);
 	sqlite3_bind_int(stmt, 2, utxo->outnum);
 	sqlite3_bind_amount_sat(stmt, 3, utxo->amount);
@@ -102,6 +102,13 @@ bool wallet_add_utxo(struct wallet *w, struct utxo *utxo,
 	else
 		sqlite3_bind_null(stmt, 11);
 
+	if (utxo->scriptPubkey)
+		sqlite3_bind_blob(stmt, 12, utxo->scriptPubkey,
+				  tal_bytelen(utxo->scriptPubkey),
+				  SQLITE_TRANSIENT);
+	else
+		sqlite3_bind_null(stmt, 12);
+
 	/* May fail if we already know about the tx, e.g., because
 	 * it's change or some internal tx. */
 	return db_exec_prepared_mayfail(w->db, stmt);
@@ -131,6 +138,7 @@ static struct utxo *wallet_stmt2output(const tal_t *ctx, sqlite3_stmt *stmt)
 
 	utxo->blockheight = NULL;
 	utxo->spendheight = NULL;
+	utxo->scriptPubkey = NULL;
 
 	if (sqlite3_column_type(stmt, 9) != SQLITE_NULL) {
 		blockheight = tal(utxo, u32);
@@ -144,6 +152,12 @@ static struct utxo *wallet_stmt2output(const tal_t *ctx, sqlite3_stmt *stmt)
 		utxo->spendheight = spendheight;
 	}
 
+	if (sqlite3_column_type(stmt, 11) != SQLITE_NULL) {
+		utxo->scriptPubkey =
+		    tal_dup_arr(utxo, u8, sqlite3_column_blob(stmt, 11),
+				sqlite3_column_bytes(stmt, 11), 0);
+	}
+
 	return utxo;
 }
 
@@ -1162,6 +1176,7 @@ int wallet_extract_owned_outputs(struct wallet *w, const struct bitcoin_tx *tx,
 
 		utxo->blockheight = blockheight ? blockheight : NULL;
 		utxo->spendheight = NULL;
+		utxo->scriptPubkey = tx->output[output].script;
 
 		log_debug(w->log, "Owning output %zu %s (%s) txid %s%s",
 			  output,