lightningd: generalize htlc_set.

Make it a set of arbitrary data, so we can use it for local payments,
not just HTLCs.

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

lightningd/htlc_set.c

@@ -8,15 +8,32 @@
 #include <lightningd/lightningd.h>
 #include <lightningd/peer_htlcs.h>
 
-/* If an HTLC times out, we need to free entire set, since we could be processing
- * it in invoice.c right now. */
-static void htlc_set_hin_destroyed(struct htlc_in *hin,
+static struct incoming_payment *new_inpay(const tal_t *ctx,
+					  struct logger *log,
+					  struct amount_msat msat,
+					  void (*fail)(void *, const u8 *),
+					  void (*succeeded)(void *,
+							    const struct preimage *),
+					  void *arg)
+{
+	struct incoming_payment *inpay = tal(ctx, struct incoming_payment);
+	inpay->log = log;
+	inpay->msat = msat;
+	inpay->fail = fail;
+	inpay->succeeded = succeeded;
+	inpay->arg = arg;
+	return inpay;
+}
+
+/* If an HTLC times out, we need to free entire set, since we could be
+ * processing it in invoice.c right now. */
+static void htlc_set_inpay_destroyed(struct incoming_payment *inpay,
 				     struct htlc_set *set)
 {
-	for (size_t i = 0; i < tal_count(set->htlcs); i++) {
-		if (set->htlcs[i] == hin) {
+	for (size_t i = 0; i < tal_count(set->inpays); i++) {
+		if (set->inpays[i] == inpay) {
 			/* Don't try to re-fail this HTLC! */
-			tal_arr_remove(&set->htlcs, i);
+			tal_arr_remove(&set->inpays, i);
 			/* Kind of the correct failure code. */
 			htlc_set_fail(set, take(towire_mpp_timeout(NULL)));
 			return;
@@ -49,42 +66,45 @@ void htlc_set_fail_(struct htlc_set *set, const u8 *failmsg TAKES,
 	if (taken(failmsg))
 		tal_steal(set, failmsg);
 
-	for (size_t i = 0; i < tal_count(set->htlcs); i++) {
+	for (size_t i = 0; i < tal_count(set->inpays); i++) {
 		const u8 *this_failmsg;
 
 		/* Don't remove from set */
-		tal_del_destructor2(set->htlcs[i], htlc_set_hin_destroyed, set);
+		tal_del_destructor2(set->inpays[i], htlc_set_inpay_destroyed, set);
 
 		if (tal_bytelen(failmsg) == 0)
-			this_failmsg = towire_incorrect_or_unknown_payment_details(tmpctx, set->htlcs[i]->msat, get_block_height(set->ld->topology));
+			this_failmsg = towire_incorrect_or_unknown_payment_details(tmpctx, set->inpays[i]->msat, get_block_height(set->ld->topology));
 		else
 			this_failmsg = failmsg;
 
-		log_debug(set->htlcs[i]->key.channel->log,
+		log_debug(set->inpays[i]->log,
 			  "failing with %s: %s:%u",
 			  onion_wire_name(fromwire_peektype(this_failmsg)),
 			  file, line);
-		local_fail_in_htlc(set->htlcs[i], this_failmsg);
+		/* Attach inpays[i] to set so it's freed below (not with arg) */
+		tal_steal(set->inpays, set->inpays[i]);
+		set->inpays[i]->fail(set->inpays[i]->arg, this_failmsg);
 	}
 	tal_free(set);
 }
 
 void htlc_set_fulfill(struct htlc_set *set, const struct preimage *preimage)
 {
-	for (size_t i = 0; i < tal_count(set->htlcs); i++) {
+	for (size_t i = 0; i < tal_count(set->inpays); i++) {
 		/* Don't remove from set */
-		tal_del_destructor2(set->htlcs[i], htlc_set_hin_destroyed, set);
+		tal_del_destructor2(set->inpays[i],
+				    htlc_set_inpay_destroyed, set);
 
-		/* mark that we filled -- needed for tagging coin mvt */
-		set->htlcs[i]->we_filled = tal(set->htlcs[i], bool);
-		*set->htlcs[i]->we_filled = true;
-		fulfill_htlc(set->htlcs[i], preimage);
+		/* Reparent set->inpays[i] so it's freed with set */
+		tal_steal(set->inpays, set->inpays[i]);
+		set->inpays[i]->succeeded(set->inpays[i]->arg, preimage);
 	}
 	tal_free(set);
 }
 
 static struct htlc_set *new_htlc_set(struct lightningd *ld,
-				     struct htlc_in *hin,
+				     struct incoming_payment *inpay,
+				     const struct sha256 *payment_hash,
 				     struct amount_msat total_msat)
 {
 	struct htlc_set *set;
@@ -92,10 +112,10 @@ static struct htlc_set *new_htlc_set(struct lightningd *ld,
 	set = tal(ld, struct htlc_set);
 	set->ld = ld;
 	set->total_msat = total_msat;
-	set->payment_hash = hin->payment_hash;
+	set->payment_hash = *payment_hash;
 	set->so_far = AMOUNT_MSAT(0);
-	set->htlcs = tal_arr(set, struct htlc_in *, 1);
-	set->htlcs[0] = hin;
+	set->inpays = tal_arr(set, struct incoming_payment *, 1);
+	set->inpays[0] = inpay;
 
 	/* BOLT #4:
 	 * - MUST fail all HTLCs in the HTLC set after some reasonable
@@ -110,11 +130,17 @@ static struct htlc_set *new_htlc_set(struct lightningd *ld,
 	return set;
 }
 
-void htlc_set_add(struct lightningd *ld,
-		  struct htlc_in *hin,
+void htlc_set_add_(struct lightningd *ld,
+		   struct logger *log,
+		   struct amount_msat msat,
 		   struct amount_msat total_msat,
-		  const struct secret *payment_secret)
+		   const struct sha256 *payment_hash,
+		   const struct secret *payment_secret,
+		   void (*fail)(void *, const u8 *),
+		   void (*succeeded)(void *, const struct preimage *),
+		   void *arg)
 {
+	struct incoming_payment *inpay;
 	struct htlc_set *set;
 	const struct invoice_details *details;
 	const char *err;
@@ -125,23 +151,21 @@ void htlc_set_add(struct lightningd *ld,
 	 *     [Failure Messages](#failure-messages)
 	 *     - Note: "amount paid" specified there is the `total_msat` field.
 	 */
-	details = invoice_check_payment(tmpctx, ld, &hin->payment_hash,
+	details = invoice_check_payment(tmpctx, ld, payment_hash,
 					total_msat, payment_secret, &err);
 	if (!details) {
-		log_debug(hin->key.channel->log, "payment failed: %s", err);
-		local_fail_in_htlc(hin,
-				   take(failmsg_incorrect_or_unknown(NULL, ld, hin->msat)));
+		log_debug(log, "payment failed: %s", err);
+		fail(arg, take(failmsg_incorrect_or_unknown(NULL, ld, msat)));
 		return;
 	}
 
 	/* If we insist on a payment secret, it must always have it */
 	if (feature_is_set(details->features, COMPULSORY_FEATURE(OPT_PAYMENT_SECRET))
 	    && !payment_secret) {
-		log_debug(hin->key.channel->log,
+		log_debug(log,
 			  "Missing payment_secret, but required for %s",
-			  fmt_sha256(tmpctx, &hin->payment_hash));
-		local_fail_in_htlc(hin,
-				   take(failmsg_incorrect_or_unknown(NULL, ld, hin->msat)));
+			  fmt_sha256(tmpctx, payment_hash));
+		fail(arg, take(failmsg_incorrect_or_unknown(NULL, ld, msat)));
 		return;
 	}
 
@@ -149,9 +173,10 @@ void htlc_set_add(struct lightningd *ld,
 	 *  - otherwise, if it supports `basic_mpp`:
 	 *    - MUST add it to the HTLC set corresponding to that `payment_hash`.
 	 */
-	set = htlc_set_map_get(ld->htlc_sets, &hin->payment_hash);
+	inpay = new_inpay(arg, log, msat, fail, succeeded, arg);
+	set = htlc_set_map_get(ld->htlc_sets, payment_hash);
 	if (!set)
-		set = new_htlc_set(ld, hin, total_msat);
+		set = new_htlc_set(ld, inpay, payment_hash, total_msat);
 	else {
 		/* BOLT #4:
 		 *
@@ -165,48 +190,48 @@ void htlc_set_add(struct lightningd *ld,
 		/* We check this now, since we want to fail with this as soon
 		 * as possible, to avoid other probing attacks. */
 		if (!payment_secret) {
-			log_debug(hin->key.channel->log,
+			log_debug(log,
 				  "Missing payment_secret, but required for MPP");
-			local_fail_in_htlc(hin, take(failmsg_incorrect_or_unknown(NULL, ld, hin->msat)));
+			fail(arg, take(failmsg_incorrect_or_unknown(NULL, ld, msat)));
 			return;
 		}
-		tal_arr_expand(&set->htlcs, hin);
+		tal_arr_expand(&set->inpays, inpay);
 	}
 
 	/* Remove from set should hin get destroyed somehow */
-	tal_add_destructor2(hin, htlc_set_hin_destroyed, set);
+	tal_add_destructor2(inpay, htlc_set_inpay_destroyed, set);
 
 	/* BOLT #4:
 	 * - SHOULD fail the entire HTLC set if `total_msat` is not
 	 *   the same for all HTLCs in the set.
 	 */
 	if (!amount_msat_eq(total_msat, set->total_msat)) {
-		log_unusual(ld->log, "Failing HTLC set %s:"
+		log_unusual(log, "Failing HTLC set %s:"
 			    " total_msat %s new htlc total %s",
 			    fmt_sha256(tmpctx, &set->payment_hash),
 			    fmt_amount_msat(tmpctx, set->total_msat),
 			    fmt_amount_msat(tmpctx, total_msat));
 		htlc_set_fail(set,
 			      take(towire_final_incorrect_htlc_amount(NULL,
-								      hin->msat)));
+								      msat)));
 		return;
 	}
 
-	if (!amount_msat_accumulate(&set->so_far, hin->msat)) {
+	if (!amount_msat_accumulate(&set->so_far, msat)) {
 		log_unusual(ld->log, "Failing HTLC set %s:"
 			    " overflow adding %s+%s",
 			    fmt_sha256(tmpctx, &set->payment_hash),
 			    fmt_amount_msat(tmpctx, set->so_far),
-			    fmt_amount_msat(tmpctx, hin->msat));
+			    fmt_amount_msat(tmpctx, msat));
 		htlc_set_fail(set,
 			      take(towire_final_incorrect_htlc_amount(NULL,
-								      hin->msat)));
+								      msat)));
 		return;
 	}
 
 	log_debug(ld->log,
 		  "HTLC set contains %zu HTLCs, for a total of %s out of %s (%spayment_secret)",
-		  tal_count(set->htlcs),
+		  tal_count(set->inpays),
 		  fmt_amount_msat(tmpctx, set->so_far),
 		  fmt_amount_msat(tmpctx, total_msat),
 		  payment_secret ? "" : "no "

lightningd/htlc_set.h

@@ -9,15 +9,28 @@
 #include <common/utils.h>
 #include <wire/onion_wire.h>
 
-struct htlc_in;
 struct lightningd;
+struct logger;
+
+/* Could be an incoming HTLC, could be a local payment */
+struct incoming_payment {
+	/* Where to log */
+	struct logger *log;
+	/* Amount of this payment */
+	struct amount_msat msat;
+	/* If it fails */
+	void (*fail)(void *arg, const u8 *failmsg TAKES);
+	/* If it succeeded: here's the preimage. */
+	void (*succeeded)(void *arg, const struct preimage *preimage);
+	void *arg;
+};
 
 /* Set of incoming HTLCs for multi-part-payments */
 struct htlc_set {
 	struct lightningd *ld;
 	struct amount_msat total_msat, so_far;
 	struct sha256 payment_hash;
-	struct htlc_in **htlcs;
+	struct incoming_payment **inpays;
 	struct oneshot *timeout;
 };
 
@@ -43,11 +56,28 @@ HTABLE_DEFINE_TYPE(struct htlc_set,
 		   htlc_set_eq,
 		   htlc_set_map);
 
-/* Handles hin: if it completes a set, hands that to invoice_try_pay */
-void htlc_set_add(struct lightningd *ld,
-		  struct htlc_in *hin,
+/* Handles arg: if it completes a set, calls invoice_try_pay */
+void htlc_set_add_(struct lightningd *ld,
+		   struct logger *log,
+		   struct amount_msat msat,
 		   struct amount_msat total_msat,
-		  const struct secret *payment_secret);
+		   const struct sha256 *payment_hash,
+		   const struct secret *payment_secret,
+		   void (*fail)(void *, const u8 *),
+		   void (*succeeded)(void *, const struct preimage *),
+		   void *arg);
+
+#define htlc_set_add(ld, log, msat, total_msat, payment_hash, payment_secret, \
+		     fail, succeeded, arg)				\
+	htlc_set_add_((ld), (log), (msat), (total_msat), (payment_hash), \
+		      (payment_secret),					\
+		      typesafe_cb_postargs(void, void *,		\
+					   (fail), (arg),		\
+					   const u8 *),			\
+		      typesafe_cb_postargs(void, void *,		\
+					   (succeeded), (arg),		\
+					   const struct preimage *),	\
+		      (arg))
 
 /* Fail every htlc in the set: frees set.  If failmsg is NULL/zero-length,
  * it sends each one a WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS. */

lightningd/invoice.c

@@ -176,10 +176,14 @@ static void invoice_payment_add_tlvs(struct json_stream *stream,
 {
 	struct htlc_in *hin;
 	const struct tlv_payload *tlvs;
-	assert(tal_count(hset->htlcs) > 0);
+	assert(tal_count(hset->inpays) > 0);
+
+	/* Only do this if it's actually an HTLC */
+	if ((void *)hset->inpays[0]->fail != (void *)local_fail_in_htlc)
+		return;
 
 	/* Pick the first HTLC as representative for the entire set. */
-	hin = hset->htlcs[0];
+	hin = hset->inpays[0]->arg;
 
 	tlvs = hin->payload->tlv;
 
@@ -291,7 +295,7 @@ invoice_payment_hooks_done(struct invoice_payment_hook_payload *payload STEALS)
 	log_info(ld->log, "Resolved invoice '%s' with amount %s in %zu htlcs",
 		 payload->label->s,
 		 fmt_amount_msat(tmpctx, payload->msat),
-		 payload->set ? tal_count(payload->set->htlcs) : 0);
+		 payload->set ? tal_count(payload->set->inpays) : 0);
 	if (payload->set)
 		htlc_set_fulfill(payload->set, &payload->preimage);
 

lightningd/peer_htlcs.c

@@ -407,6 +407,16 @@ void fulfill_htlc(struct htlc_in *hin, const struct preimage *preimage)
 	subd_send_msg(channel->owner, take(msg));
 }
 
+/* HTLC-specific wrappers */
+static void htlc_set_fulfill_htlc(struct htlc_in *hin,
+				  const struct preimage *preimage)
+{
+	/* mark that we filled -- needed for tagging coin mvt */
+	hin->we_filled = tal(hin, bool);
+	*hin->we_filled = true;
+	fulfill_htlc(hin, preimage);
+}
+
 static void handle_localpay(struct htlc_in *hin,
 			    struct amount_msat amt_to_forward,
 			    u32 outgoing_cltv_value,
@@ -499,7 +509,13 @@ static void handle_localpay(struct htlc_in *hin,
 		goto fail;
 	}
 
-	htlc_set_add(ld, hin, total_msat, payment_secret);
+	htlc_set_add(ld, hin->key.channel->log,
+		     hin->msat, total_msat,
+		     &hin->payment_hash,
+		     payment_secret,
+		     local_fail_in_htlc,
+		     htlc_set_fulfill_htlc,
+		     hin);
 	return;
 
 fail:

lightningd/test/run-invoice-select-inchan.c

@@ -694,6 +694,9 @@ struct jsonrpc_request *jsonrpc_request_start_(
 void kill_uncommitted_channel(struct uncommitted_channel *uc UNNEEDED,
 			      const char *why UNNEEDED)
 { fprintf(stderr, "kill_uncommitted_channel called!\n"); abort(); }
+/* Generated stub for local_fail_in_htlc */
+void local_fail_in_htlc(struct htlc_in *hin UNNEEDED, const u8 *failmsg TAKES UNNEEDED)
+{ fprintf(stderr, "local_fail_in_htlc called!\n"); abort(); }
 /* Generated stub for lockin_complete */
 void lockin_complete(struct channel *channel UNNEEDED,
 		     enum channel_state expected_state UNNEEDED)

wallet/test/run-wallet.c

@@ -359,12 +359,17 @@ bool htlc_is_trimmed(enum side htlc_owner UNNEEDED,
 		     bool option_anchor_outputs UNNEEDED,
 		     bool option_anchors_zero_fee_htlc_tx UNNEEDED)
 { fprintf(stderr, "htlc_is_trimmed called!\n"); abort(); }
-/* Generated stub for htlc_set_add */
-void htlc_set_add(struct lightningd *ld UNNEEDED,
-		  struct htlc_in *hin UNNEEDED,
+/* Generated stub for htlc_set_add_ */
+void htlc_set_add_(struct lightningd *ld UNNEEDED,
+		   struct logger *log UNNEEDED,
+		   struct amount_msat msat UNNEEDED,
 		   struct amount_msat total_msat UNNEEDED,
-		  const struct secret *payment_secret UNNEEDED)
-{ fprintf(stderr, "htlc_set_add called!\n"); abort(); }
+		   const struct sha256 *payment_hash UNNEEDED,
+		   const struct secret *payment_secret UNNEEDED,
+		   void (*fail)(void * UNNEEDED, const u8 *) UNNEEDED,
+		   void (*succeeded)(void * UNNEEDED, const struct preimage *) UNNEEDED,
+		   void *arg UNNEEDED)
+{ fprintf(stderr, "htlc_set_add_ called!\n"); abort(); }
 /* Generated stub for invoice_check_payment */
 const struct invoice_details *invoice_check_payment(const tal_t *ctx UNNEEDED,
 						    struct lightningd *ld UNNEEDED,