channeld: add hsm_capabilities and add hsm_is_capable to common

Changelog-Added: Added hsm_capabilities and hsm_is_capable to channeld.

channeld/channeld.c

@@ -77,6 +77,9 @@ struct peer {
 	/* Features we support. */
 	struct feature_set *our_features;
 
+	/* What (additional) messages the HSM accepts */
+	u32 *hsm_capabilities;
+
 	/* Tolerable amounts for feerate (only relevant for fundee). */
 	u32 feerate_min, feerate_max;
 
@@ -6085,6 +6088,7 @@ static void init_channel(struct peer *peer)
 	if (!fromwire_channeld_init(peer, msg,
 				    &chainparams,
 				    &peer->our_features,
+				    &peer->hsm_capabilities,
 				    &peer->channel_id,
 				    &funding,
 				    &funding_sats,

channeld/channeld_wire.csv

@@ -15,6 +15,8 @@
 msgtype,channeld_init,1000
 msgdata,channeld_init,chainparams,chainparams,
 msgdata,channeld_init,our_features,feature_set,
+msgdata,channeld_init,num_hsm_capabilities,u16,
+msgdata,channeld_init,hsm_capabilities,u32,num_hsm_capabilities
 msgdata,channeld_init,channel_id,channel_id,
 msgdata,channeld_init,funding,bitcoin_outpoint,
 msgdata,channeld_init,funding_satoshi,amount_sat,

common/Makefile

@@ -41,6 +41,7 @@ COMMON_SRC_NOGEN :=				\
 	common/gossmap.c			\
 	common/hash_u5.c			\
 	common/hmac.c				\
+	common/hsm_capable.c			\
 	common/hsm_encryption.c			\
 	common/htlc_state.c			\
 	common/htlc_trim.c			\

common/hsm_capable.c

@@ -0,0 +1,13 @@
+#include "config.h"
+#include <common/hsm_capable.h>
+
+/* Is this capability supported by the HSM? (So far, always a message
+ * number) */
+bool hsm_is_capable(u32 *capabilities, u32 msgtype)
+{
+	for (size_t i = 0; i < tal_count(capabilities); i++) {
+		if (capabilities[i] == msgtype)
+			return true;
+	}
+	return false;
+}

common/hsm_capable.h

@@ -0,0 +1,11 @@
+#ifndef LIGHTNING_COMMON_HSM_CAPABLE_H
+#define LIGHTNING_COMMON_HSM_CAPABLE_H
+#include "config.h"
+#include <ccan/short_types/short_types.h>
+#include <ccan/tal/tal.h>
+#include <stdbool.h>
+
+/* Is this capability supported by the HSM? (So far, always a message
+ * number) */
+bool hsm_is_capable(u32 *capabilities, u32 msgtype);
+#endif /* LIGHTNING_COMMON_HSM_CAPABLE_H */

lightningd/Makefile

@@ -103,6 +103,7 @@ LIGHTNINGD_COMMON_OBJS :=			\
 	common/status_wiregen.o			\
 	common/hash_u5.o			\
 	common/hmac.o				\
+	common/hsm_capable.o			\
 	common/hsm_encryption.o			\
 	common/htlc_state.o			\
 	common/htlc_trim.o			\

lightningd/channel_control.c

@@ -1626,6 +1626,9 @@ bool peer_start_channeld(struct channel *channel,
 	initmsg = towire_channeld_init(tmpctx,
 				       chainparams,
 				       ld->our_features,
+				       /* Capabilities arg needs to be a tal array */
+				       tal_dup_arr(tmpctx, u32, ld->hsm_capabilities,
+						   tal_count(ld->hsm_capabilities), 0),
 				       &channel->cid,
 				       &channel->funding,
 				       channel->funding_sats,

lightningd/hsm_control.c

@@ -3,6 +3,7 @@
 #include <ccan/fdpass/fdpass.h>
 #include <common/ecdh.h>
 #include <common/errcode.h>
+#include <common/hsm_capable.h>
 #include <common/hsm_encryption.h>
 #include <common/hsm_version.h>
 #include <common/invoice_path_id.h>
@@ -78,11 +79,7 @@ static unsigned int hsm_msg(struct subd *hsmd,
  * number) */
 bool hsm_capable(struct lightningd *ld, u32 msgtype)
 {
-	for (size_t i = 0; i < tal_count(ld->hsm_capabilities); i++) {
-		if (ld->hsm_capabilities[i] == msgtype)
-			return true;
-	}
-	return false;
+	return hsm_is_capable(ld->hsm_capabilities, msgtype);
 }
 
 struct ext_key *hsm_init(struct lightningd *ld)

wallet/test/Makefile

@@ -14,6 +14,7 @@ WALLET_TEST_COMMON_OBJS :=			\
 	common/derive_basepoints.o		\
 	common/features.o			\
 	common/htlc_state.o			\
+	common/hsm_capable.o			\
 	common/htlc_wire.o			\
 	common/fee_states.o			\
 	common/type_to_string.o			\