Remove txid normalization.

Since any transaction with all segregated-witness inputs is non-malleable,
and all our transactions are that, we can remove normalized txids.

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

daemon/bitcoind.c

@@ -414,23 +414,6 @@ void bitcoind_getblockhash_(struct lightningd_state *dstate,
 			  "getblockhash", str, NULL);
 }
 
-/* FIXME: Seg witness removes need for this! */
-void normalized_txid(const struct bitcoin_tx *tx, struct sha256_double *txid)
-{
-	size_t i;
-	struct bitcoin_tx tx_copy = *tx;
-	struct bitcoin_tx_input input_copy[tx->input_count];
-
-	/* Copy inputs, but scripts are 0 length. */
-	for (i = 0; i < tx_copy.input_count; i++) {
-		input_copy[i] = tx->input[i];
-		input_copy[i].script_length = 0;
-	}
-	tx_copy.input = input_copy;
-
-	bitcoin_txid(&tx_copy, txid);
-}
-
 /* Make testnet/regtest status matches us. */
 void check_bitcoind_config(struct lightningd_state *dstate)
 {

daemon/bitcoind.h

@@ -87,7 +87,5 @@ void bitcoind_getrawblock_(struct lightningd_state *dstate,
 						  struct bitcoin_block *), \
 			      (arg))
 
-void normalized_txid(const struct bitcoin_tx *tx, struct sha256_double *txid);
-
 void check_bitcoind_config(struct lightningd_state *dstate);
 #endif /* LIGHTNING_DAEMON_BITCOIND_H */

daemon/chaintopology.c

@@ -152,12 +152,8 @@ static void connect_blocks(struct lightningd_state *dstate, struct block *b)
 		}
 
 		/* We do spends first, in case that tells us to watch tx. */
-		normalized_txid(tx, &txid);
-		w = txwatch_hash_get(&dstate->txwatches, &txid);
-		if (!w) {
 		bitcoin_txid(tx, &txid);
 		w = txwatch_hash_get(&dstate->txwatches, &txid);
-		}
 		if (w) {
 			add_tx_to_block(b, w);
 			/* Fire if it's the first we've seen it: this might

daemon/peer.c

@@ -876,7 +876,7 @@ static void watch_commit_outputs(struct peer *peer, const struct bitcoin_tx *tx)
 	varint_t i;
 	struct sha256_double txid;
 
-	normalized_txid(tx, &txid);
+	bitcoin_txid(tx, &txid);
 	for (i = 0; i < tx->output_count; i++) {
 		watch_txo(peer, peer, &txid, i, our_commit_spent,
 			  peer->us.commit);

daemon/watch.c

@@ -116,7 +116,7 @@ struct txwatch *watch_tx_(const tal_t *ctx,
 {
 	struct sha256_double txid;
 
-	normalized_txid(tx, &txid);
+	bitcoin_txid(tx, &txid);
 	return watch_txid(ctx, peer, &txid, cb, cb_arg);
 }
 

daemon/watch.h

@@ -114,9 +114,6 @@ struct txowatch *watch_txo_(const tal_t *ctx,
 				      const struct bitcoin_tx *),	\
 		  (cbdata))
 
-/* FIXME: Seg witness removes need for this! */
-void normalized_txid(const struct bitcoin_tx *tx, struct sha256_double *txid);
-
 void txwatch_fire(struct lightningd_state *dstate,
 		  struct txwatch *txw,
 		  unsigned int depth);