script: enhance is_p2sh/is_p2pkh/is_p2wsh/is_p2wpkh to extract addr.

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

bitcoin/script.c

@@ -368,7 +368,7 @@ u8 *p2wpkh_scriptcode(const tal_t *ctx, const struct pubkey *key)
 	return script;
 }
 
-bool is_p2pkh(const u8 *script)
+bool is_p2pkh(const u8 *script, struct bitcoin_address *addr)
 {
 	size_t script_len = tal_len(script);
 
@@ -384,10 +384,12 @@ bool is_p2pkh(const u8 *script)
 		return false;
 	if (script[24] != OP_CHECKSIG)
 		return false;
+	if (addr)
+		memcpy(addr, script+3, 20);
 	return true;
 }
 
-bool is_p2sh(const u8 *script)
+bool is_p2sh(const u8 *script, struct ripemd160 *addr)
 {
 	size_t script_len = tal_len(script);
 
@@ -399,10 +401,12 @@ bool is_p2sh(const u8 *script)
 		return false;
 	if (script[22] != OP_EQUAL)
 		return false;
+	if (addr)
+		memcpy(addr, script+2, 20);
 	return true;
 }
 
-bool is_p2wsh(const u8 *script)
+bool is_p2wsh(const u8 *script, struct sha256 *addr)
 {
 	size_t script_len = tal_len(script);
 
@@ -412,10 +416,12 @@ bool is_p2wsh(const u8 *script)
 		return false;
 	if (script[1] != OP_PUSHBYTES(sizeof(struct sha256)))
 		return false;
+	if (addr)
+		memcpy(addr, script+2, sizeof(struct sha256));
 	return true;
 }
 
-bool is_p2wpkh(const u8 *script)
+bool is_p2wpkh(const u8 *script, struct bitcoin_address *addr)
 {
 	size_t script_len = tal_len(script);
 
@@ -425,6 +431,8 @@ bool is_p2wpkh(const u8 *script)
 		return false;
 	if (script[1] != OP_PUSHBYTES(sizeof(struct ripemd160)))
 		return false;
+	if (addr)
+		memcpy(addr, script+2, sizeof(*addr));
 	return true;
 }
 

bitcoin/script.h

@@ -125,17 +125,17 @@ u8 *bitcoin_wscript_htlc_tx(const tal_t *ctx,
 			    const struct pubkey *revocation_pubkey,
 			    const struct pubkey *local_delayedkey);
 
-/* Is this a pay to pubkey hash? */
-bool is_p2pkh(const u8 *script);
+/* Is this a pay to pubkey hash? (extract addr if not NULL) */
+bool is_p2pkh(const u8 *script, struct bitcoin_address *addr);
 
-/* Is this a pay to script hash? */
-bool is_p2sh(const u8 *script);
+/* Is this a pay to script hash? (extract addr if not NULL) */
+bool is_p2sh(const u8 *script, struct ripemd160 *addr);
 
-/* Is this (version 0) pay to witness script hash? */
-bool is_p2wsh(const u8 *script);
+/* Is this (version 0) pay to witness script hash? (extract addr if not NULL) */
+bool is_p2wsh(const u8 *script, struct sha256 *addr);
 
-/* Is this (version 0) pay to witness pubkey hash? */
-bool is_p2wpkh(const u8 *script);
+/* Is this (version 0) pay to witness pubkey hash? (extract addr if not NULL) */
+bool is_p2wpkh(const u8 *script, struct bitcoin_address *addr);
 
 /* Are these two scripts equal? */
 bool scripteq(const tal_t *s1, const tal_t *s2);

lightningd/peer_control.c

@@ -1620,8 +1620,8 @@ static void peer_got_shutdown(struct peer *peer, const u8 *msg)
 	 *
 	 * A receiving node SHOULD fail the connection if the `scriptpubkey`
 	 * is not one of those forms. */
-	if (!is_p2pkh(scriptpubkey) && !is_p2sh(scriptpubkey)
-	    && !is_p2wpkh(scriptpubkey) && !is_p2wsh(scriptpubkey)) {
+	if (!is_p2pkh(scriptpubkey, NULL) && !is_p2sh(scriptpubkey, NULL)
+	    && !is_p2wpkh(scriptpubkey, NULL) && !is_p2wsh(scriptpubkey, NULL)) {
 		char *str = tal_fmt(peer, "Bad shutdown scriptpubkey %s",
 				    tal_hex(peer, scriptpubkey));
 		peer_fail_permanent_str(peer, take(str));

onchaind/onchain.c

@@ -1086,7 +1086,7 @@ static int match_htlc_output(const struct bitcoin_tx *tx,
 			     u8 **htlc_scripts)
 {
 	/* Must be a p2wsh output */
-	if (!is_p2wsh(tx->output[outnum].script))
+	if (!is_p2wsh(tx->output[outnum].script, NULL))
 		return -1;
 
 	for (size_t i = 0; i < tal_count(htlc_scripts); i++) {

wallet/wallet.c

@@ -195,9 +195,9 @@ bool wallet_can_spend(struct wallet *w, const u8 *script,
 	u32 i;
 
 	/* If not one of these, can't be for us. */
-	if (is_p2sh(script))
+	if (is_p2sh(script, NULL))
 		*output_is_p2sh = true;
-	else if (is_p2wpkh(script))
+	else if (is_p2wpkh(script, NULL))
 		*output_is_p2sh = false;
 	else
 		return false;