Factored psbt_add_keypath_to_last_output into common.

Author: ksedgwic

channeld/Makefile

@@ -72,6 +72,7 @@ CHANNELD_COMMON_OBJS :=				\
 	common/per_peer_state.o			\
 	common/permute_tx.o			\
 	common/ping.o				\
+	common/psbt_internal.o		\
 	common/psbt_open.o			\
 	common/private_channel_announcement.o	\
 	common/pseudorand.o			\

channeld/watchtower.c

@@ -7,42 +7,14 @@
 #include <common/htlc_tx.h>
 #include <common/key_derive.h>
 #include <common/keyset.h>
+#include <common/psbt_internal.h>
 #include <common/status.h>
 #include <common/type_to_string.h>
 #include <hsmd/hsmd_wiregen.h>
 #include <wire/wire_sync.h>
 
 static const u8 ONE = 0x1;
 
-static void add_keypath_item_to_last_output(struct bitcoin_tx *tx,
-					    u32 index,
-					    const struct ext_key *ext) {
-	// Skip if there is no wallet keypath for this output.
-	if (index == UINT32_MAX)
-		return;
-
-	size_t outndx = tx->psbt->num_outputs - 1;
-	struct wally_map *map_in = &tx->psbt->outputs[outndx].keypaths;
-
-	u8 fingerprint[BIP32_KEY_FINGERPRINT_LEN];
-	if (bip32_key_get_fingerprint(
-		    (struct ext_key *) ext, fingerprint, sizeof(fingerprint)) != WALLY_OK) {
-		abort();
-	}
-
-	u32 path[1];
-	path[0] = index;
-
-	tal_wally_start();
-	if (wally_map_add_keypath_item(map_in,
-				       ext->pub_key, sizeof(ext->pub_key),
-				       fingerprint, sizeof(fingerprint),
-				       path, 1) != WALLY_OK) {
-		abort();
-	}
-	tal_wally_end(tx->psbt);
-}
-
 const struct bitcoin_tx *
 penalty_tx_create(const tal_t *ctx,
 		  const struct channel *channel,
@@ -104,7 +76,7 @@ penalty_tx_create(const tal_t *ctx,
 			     NULL, to_them_sats, NULL, wscript);
 
 	bitcoin_tx_add_output(tx, final_scriptpubkey, NULL, to_them_sats);
-	add_keypath_item_to_last_output(tx, final_index, final_ext_key);
+	psbt_add_keypath_to_last_output(tx, final_index, final_ext_key);
 
 	/* Worst-case sig is 73 bytes */
 	weight = bitcoin_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(wscript);

closingd/Makefile

@@ -46,6 +46,7 @@ CLOSINGD_COMMON_OBJS :=				\
 	common/peer_failed.o			\
 	common/per_peer_state.o			\
 	common/permute_tx.o			\
+	common/psbt_internal.o			\
 	common/psbt_open.o			\
 	common/pseudorand.o			\
 	common/read_peer_msg.o			\

common/close_tx.c

@@ -2,38 +2,10 @@
 #include "bitcoin/tx.h"
 #include "close_tx.h"
 #include "permute_tx.h"
+#include "psbt_internal.h"
 #include <assert.h>
 #include <common/utils.h>
 
-static void add_keypath_item_to_last_output(struct bitcoin_tx *tx,
-					    u32 index,
-					    const struct ext_key *ext) {
-	// Skip if there is no wallet keypath for this output.
-	if (index == UINT32_MAX)
-		return;
-
-	size_t outndx = tx->psbt->num_outputs - 1;
-	struct wally_map *map_in = &tx->psbt->outputs[outndx].keypaths;
-
-	u8 fingerprint[BIP32_KEY_FINGERPRINT_LEN];
-	if (bip32_key_get_fingerprint(
-		    (struct ext_key *) ext, fingerprint, sizeof(fingerprint)) != WALLY_OK) {
-		abort();
-	}
-
-	u32 path[1];
-	path[0] = index;
-
-	tal_wally_start();
-	if (wally_map_add_keypath_item(map_in,
-				       ext->pub_key, sizeof(ext->pub_key),
-				       fingerprint, sizeof(fingerprint),
-				       path, 1) != WALLY_OK) {
-		abort();
-	}
-	tal_wally_end(tx->psbt);
-}
-
 struct bitcoin_tx *create_close_tx(const tal_t *ctx,
 				   const struct chainparams *chainparams,
 				   u32 local_wallet_index,
@@ -78,7 +50,7 @@ struct bitcoin_tx *create_close_tx(const tal_t *ctx,
 		script = tal_dup_talarr(tx, u8, our_script);
 		/* One output is to us. */
 		bitcoin_tx_add_output(tx, script, NULL, to_us);
-		add_keypath_item_to_last_output(tx, local_wallet_index, local_wallet_ext_key);
+		psbt_add_keypath_to_last_output(tx, local_wallet_index, local_wallet_ext_key);
 		num_outputs++;
 	}
 

common/psbt_internal.c

@@ -102,3 +102,33 @@ psbt_to_witness_stacks(const tal_t *ctx,
 	tal_resize(&stacks, stack_index);
 	return stacks;
 }
+
+void psbt_add_keypath_to_last_output(struct bitcoin_tx *tx,
+				     u32 index,
+				     const struct ext_key *ext) {
+	// Skip if there is no wallet keypath for this output.
+	if (index == UINT32_MAX)
+		return;
+
+	size_t outndx = tx->psbt->num_outputs - 1;
+	struct wally_map *map_in = &tx->psbt->outputs[outndx].keypaths;
+
+	u8 fingerprint[BIP32_KEY_FINGERPRINT_LEN];
+	if (bip32_key_get_fingerprint(
+		    (struct ext_key *) ext, fingerprint, sizeof(fingerprint)) != WALLY_OK) {
+		return; /* FIXME: throw an error ? */
+	}
+
+	u32 path[1];
+	path[0] = index;
+
+	tal_wally_start();
+	if (wally_map_add_keypath_item(map_in,
+				       ext->pub_key, sizeof(ext->pub_key),
+				       fingerprint, sizeof(fingerprint),
+				       path, 1) != WALLY_OK) {
+		return; /* FIXME: throw an error ? */
+	}
+	tal_wally_end(tx->psbt);
+}
+

common/psbt_internal.h

@@ -2,9 +2,12 @@
 #define LIGHTNING_COMMON_PSBT_INTERNAL_H
 
 #include "config.h"
+#include <ccan/short_types/short_types.h>
 #include <ccan/tal/tal.h>
 #include <common/tx_roles.h>
 
+struct bitcoin_tx;
+struct ext_key;
 struct wally_psbt;
 struct wally_psbt_input;
 struct witness_element;
@@ -32,4 +35,11 @@ psbt_to_witness_stacks(const tal_t *ctx,
 		       const struct wally_psbt *psbt,
 		       enum tx_role side_to_stack);
 
+/* psbt_add_keypath_to_last_output - augment the last output with the
+ * given wallet keypath
+ */
+void psbt_add_keypath_to_last_output(struct bitcoin_tx *tx,
+				     u32 index,
+				     const struct ext_key *ext);
+
 #endif /* LIGHTNING_COMMON_PSBT_INTERNAL_H */

onchaind/Makefile

@@ -53,6 +53,7 @@ ONCHAIND_COMMON_OBJS :=				\
 	common/onionreply.o			\
 	common/peer_billboard.o			\
 	common/permute_tx.o			\
+	common/psbt_internal.o			\
 	common/psbt_open.o			\
 	common/pseudorand.o			\
 	common/setup.o				\

onchaind/onchaind.c

@@ -16,6 +16,7 @@
 #include <common/memleak.h>
 #include <common/overflows.h>
 #include <common/peer_billboard.h>
+#include <common/psbt_internal.h>
 #include <common/status.h>
 #include <common/subdaemon.h>
 #include <common/type_to_string.h>
@@ -662,35 +663,6 @@ static u8 *penalty_to_us(const tal_t *ctx,
 					     tx, wscript);
 }
 
-static void add_keypath_item_to_last_output(struct bitcoin_tx *tx,
-					    u32 index,
-					    const struct ext_key *ext) {
-	// Skip if there is no wallet keypath for this output.
-	if (index == UINT32_MAX)
-		return;
-
-	size_t outndx = tx->psbt->num_outputs - 1;
-	struct wally_map *map_in = &tx->psbt->outputs[outndx].keypaths;
-
-	u8 fingerprint[BIP32_KEY_FINGERPRINT_LEN];
-	if (bip32_key_get_fingerprint(
-		    (struct ext_key *) ext, fingerprint, sizeof(fingerprint)) != WALLY_OK) {
-		abort();
-	}
-
-	u32 path[1];
-	path[0] = index;
-
-	tal_wally_start();
-	if (wally_map_add_keypath_item(map_in,
-				       ext->pub_key, sizeof(ext->pub_key),
-				       fingerprint, sizeof(fingerprint),
-				       path, 1) != WALLY_OK) {
-		abort();
-	}
-	tal_wally_end(tx->psbt);
-}
-
 /*
  * This covers:
  * 1. to-us output spend (`<local_delayedsig> 0`)
@@ -726,7 +698,7 @@ static struct bitcoin_tx *tx_to_us(const tal_t *ctx,
 
 	bitcoin_tx_add_output(
 	    tx, scriptpubkey_p2wpkh(tx, &our_wallet_pubkey), NULL, out->sat);
-	add_keypath_item_to_last_output(tx, our_wallet_index, &our_wallet_ext_key);
+	psbt_add_keypath_to_last_output(tx, our_wallet_index, &our_wallet_ext_key);
 
 	/* Worst-case sig is 73 bytes */
 	weight = bitcoin_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(wscript);
@@ -854,7 +826,7 @@ replace_penalty_tx_to_us(const tal_t *ctx,
 							  &our_wallet_pubkey),
 				      NULL,
 				      output_amount);
-		add_keypath_item_to_last_output(tx, our_wallet_index, &our_wallet_ext_key);
+		psbt_add_keypath_to_last_output(tx, our_wallet_index, &our_wallet_ext_key);
 	}
 	else
 		bitcoin_tx_add_output(tx,

onchaind/test/Makefile

@@ -12,6 +12,8 @@ ALL_TEST_PROGRAMS += $(ONCHAIND_TEST_PROGRAMS)
 ONCHAIND_TEST_COMMON_OBJS :=			\
 	common/amount.o				\
 	common/features.o			\
+	common/psbt_internal.o			\
+	common/psbt_open.o			\
 	common/pseudorand.o			\
 	common/setup.o				\
 	common/type_to_string.o			\