lightningd: add low-level offer interfaces.

The real work is done in a plugin, but provide enough API that we can
manipulate the db.

common/jsonrpc_errors.h

@@ -76,4 +76,8 @@ static const errcode_t INVOICE_STATUS_UNEXPECTED = 906;
 /* Errors from HSM crypto operations. */
 static const errcode_t HSM_ECDH_FAILED = 800;
 
+/* Errors from `offer` commands */
+static const errcode_t OFFER_ALREADY_EXISTS = 1000;
+static const errcode_t OFFER_ALREADY_DISABLED = 1001;
+
 #endif /* LIGHTNING_COMMON_JSONRPC_ERRORS_H */

lightningd/Makefile

@@ -47,6 +47,10 @@ endif
 LIGHTNINGD_SRC_NOHDR :=				\
 	lightningd/signmessage.c
 
+ifeq ($(EXPERIMENTAL_FEATURES),1)
+LIGHTNINGD_SRC_NOHDR += lightningd/offer.c
+endif
+
 LIGHTNINGD_HEADERS :=				\
 	$(LIGHTNINGD_SRC:.c=.h)			\
 	lightningd/channel_state.h		\
@@ -122,6 +126,10 @@ LIGHTNINGD_COMMON_OBJS :=			\
 	common/wire_error.o			\
 	common/wireaddr.o			\
 
+ifeq ($(EXPERIMENTAL_FEATURES),1)
+LIGHTNINGD_COMMON_OBJS += common/bolt12.o common/bolt12_merkle.o
+endif
+
 include wallet/Makefile
 
 # All together in one convenient var

lightningd/offer.c

@@ -0,0 +1,209 @@
+#include <common/bolt12.h>
+#include <common/bolt12_merkle.h>
+#include <common/json_command.h>
+#include <common/json_helpers.h>
+#include <common/jsonrpc_errors.h>
+#include <common/param.h>
+#include <hsmd/hsmd_wiregen.h>
+#include <lightningd/jsonrpc.h>
+#include <lightningd/lightningd.h>
+#include <wallet/wallet.h>
+#include <wire/wire_sync.h>
+
+static void json_populate_offer(struct json_stream *response,
+				const struct sha256 *offer_id,
+				const char *b12,
+				const struct json_escape *label,
+				enum offer_status status)
+{
+	json_add_sha256(response, "offer_id", offer_id);
+	json_add_bool(response, "active", offer_status_active(status));
+	json_add_bool(response, "single_use", offer_status_single(status));
+	json_add_string(response, "bolt12", b12);
+	if (status == OFFER_USED)
+		json_add_bool(response, "used", true);
+	if (label)
+		json_add_escaped_string(response, "label", label);
+}
+
+static struct command_result *param_b12_offer(struct command *cmd,
+					      const char *name,
+					      const char *buffer,
+					      const jsmntok_t *tok,
+					      struct tlv_offer **offer)
+{
+	char *fail;
+	*offer = offer_decode_nosig(cmd, buffer + tok->start,
+				    tok->end - tok->start,
+				    cmd->ld->our_features, chainparams, &fail);
+	if (!*offer)
+		return command_fail_badparam(cmd, name, buffer, tok, fail);
+	if ((*offer)->signature)
+		return command_fail_badparam(cmd, name, buffer, tok,
+					     "must be unsigned offer");
+	return NULL;
+}
+
+static void hsm_sign_b12_offer(struct lightningd *ld,
+			       const struct sha256 *merkle,
+			       struct bip340sig *sig)
+{
+	u8 *msg;
+
+	msg = towire_hsmd_sign_bolt12(NULL, "offer", "signature", merkle);
+
+	if (!wire_sync_write(ld->hsm_fd, take(msg)))
+		fatal("Could not write to HSM: %s", strerror(errno));
+
+	msg = wire_sync_read(tmpctx, ld->hsm_fd);
+        if (!fromwire_hsmd_sign_bolt12_reply(msg, sig))
+		fatal("HSM gave bad sign_offer_reply %s",
+		      tal_hex(msg, msg));
+}
+
+static struct command_result *json_createoffer(struct command *cmd,
+					       const char *buffer,
+					       const jsmntok_t *obj UNNEEDED,
+					       const jsmntok_t *params)
+{
+	struct json_stream *response;
+	struct json_escape *label;
+	struct tlv_offer *offer;
+	struct sha256 merkle;
+	const char *b12str;
+	bool *single_use;
+	enum offer_status status;
+
+	if (!param(cmd, buffer, params,
+		   p_req("bolt12", param_b12_offer, &offer),
+		   p_opt("label", param_label, &label),
+		   p_opt_def("single_use", param_bool, &single_use, false),
+		   NULL))
+		return command_param_failed();
+
+	if (*single_use)
+		status = OFFER_SINGLE_USE;
+	else
+		status = OFFER_MULTIPLE_USE;
+ 	merkle_tlv(offer->fields, &merkle);
+	offer->signature = tal(offer, struct bip340sig);
+	hsm_sign_b12_offer(cmd->ld, &merkle, offer->signature);
+	b12str = offer_encode(cmd, offer);
+	if (!wallet_offer_create(cmd->ld->wallet, &merkle, b12str, label,
+				 status)) {
+		return command_fail(cmd,
+				    OFFER_ALREADY_EXISTS,
+				    "Duplicate offer");
+	}
+
+	response = json_stream_success(cmd);
+	json_populate_offer(response, &merkle, b12str, label, status);
+	return command_success(cmd, response);
+}
+
+static const struct json_command createoffer_command = {
+	"createoffer",
+	"payment",
+	json_createoffer,
+	"Create and sign an offer {bolt12} with and optional {label}."
+};
+AUTODATA(json_command, &createoffer_command);
+
+static struct command_result *json_listoffers(struct command *cmd,
+					       const char *buffer,
+					       const jsmntok_t *obj UNNEEDED,
+					       const jsmntok_t *params)
+{
+	struct sha256 *offer_id;
+	struct json_stream *response;
+	struct wallet *wallet = cmd->ld->wallet;
+	const char *b12;
+	const struct json_escape *label;
+	bool *active_only;
+	enum offer_status status;
+
+	if (!param(cmd, buffer, params,
+		   p_opt("offer_id", param_sha256, &offer_id),
+		   p_opt_def("active_only", param_bool, &active_only, false),
+		   NULL))
+		return command_param_failed();
+
+	response = json_stream_success(cmd);
+	json_array_start(response, "offers");
+	if (offer_id) {
+		b12 = wallet_offer_find(tmpctx, wallet, offer_id, &label,
+					&status);
+		if (b12 && offer_status_active(status) >= *active_only) {
+			json_object_start(response, NULL);
+			json_populate_offer(response,
+					    offer_id, b12, label, status);
+			json_object_end(response);
+		}
+	} else {
+		struct db_stmt *stmt;
+		struct sha256 id;
+
+		for (stmt = wallet_offer_first(cmd->ld->wallet, &id);
+		     stmt;
+		     stmt = wallet_offer_next(cmd->ld->wallet, stmt, &id)) {
+			b12 = wallet_offer_find(tmpctx, wallet, &id,
+						&label, &status);
+			if (offer_status_active(status) >= *active_only) {
+				json_object_start(response, NULL);
+				json_populate_offer(response,
+						    &id, b12, label, status);
+				json_object_end(response);
+			}
+		}
+	}
+	json_array_end(response);
+	return command_success(cmd, response);
+}
+
+static const struct json_command listoffers_command = {
+	"listoffers",
+	"payment",
+	json_listoffers,
+	"If {offer_id} is set, show that."
+	" Otherwise, if {showdisabled} is true, list all, otherwise just non-disabled ones."
+};
+AUTODATA(json_command, &listoffers_command);
+
+static struct command_result *json_disableoffer(struct command *cmd,
+						const char *buffer,
+						const jsmntok_t *obj UNNEEDED,
+						const jsmntok_t *params)
+{
+	struct json_stream *response;
+	struct sha256 *offer_id;
+	struct wallet *wallet = cmd->ld->wallet;
+	const char *b12;
+	const struct json_escape *label;
+	enum offer_status status;
+
+	if (!param(cmd, buffer, params,
+		   p_req("offer_id", param_sha256, &offer_id),
+		   NULL))
+		return command_param_failed();
+
+	b12 = wallet_offer_find(tmpctx, wallet, offer_id, &label, &status);
+	if (!b12)
+		return command_fail(cmd, LIGHTNINGD, "Unknown offer");
+
+	if (!offer_status_active(status))
+		return command_fail(cmd, OFFER_ALREADY_DISABLED,
+				    "offer is not active");
+	status = wallet_offer_disable(wallet, offer_id, status);
+
+	response = json_stream_success(cmd);
+	json_populate_offer(response, offer_id, b12, label, status);
+	return command_success(cmd, response);
+}
+
+static const struct json_command disableoffer_command = {
+	"disableoffer",
+	"payment",
+	json_disableoffer,
+	"Disable offer {offer_id}",
+};
+AUTODATA(json_command, &disableoffer_command);