script: add helper for checking if a 'known type'

To be used for verifying remote inputs' validity

bitcoin/script.c

@@ -436,6 +436,12 @@ bool is_p2wpkh(const u8 *script, struct bitcoin_address *addr)
 	return true;
 }
 
+bool is_known_scripttype(const u8 *script)
+{
+	return is_p2wpkh(script, NULL) || is_p2wsh(script, NULL)
+		|| is_p2sh(script, NULL) || is_p2pkh(script, NULL);
+}
+
 u8 **bitcoin_witness_sig_and_element(const tal_t *ctx,
 				     const struct bitcoin_signature *sig,
 				     const void *elem, size_t elemsize,

bitcoin/script.h

@@ -135,6 +135,9 @@ bool is_p2wsh(const u8 *script, struct sha256 *addr);
 /* Is this (version 0) pay to witness pubkey hash? (extract addr if not NULL) */
 bool is_p2wpkh(const u8 *script, struct bitcoin_address *addr);
 
+/* Is this one of the four above script types? */
+bool is_known_scripttype(const u8 *script);
+
 /* Are these two scripts equal? */
 bool scripteq(const u8 *s1, const u8 *s2);