core-lightning/lightningd/invoice.c

#include "invoice.h"
#include "json.h"
#include "jsonrpc.h"
#include "lightningd.h"
#include <bitcoin/address.h>
#include <bitcoin/base58.h>
#include <bitcoin/script.h>
#include <ccan/str/hex/hex.h>
#include <ccan/tal/str/str.h>
#include <common/bech32.h>
#include <common/bolt11.h>
#include <common/json_command.h>
#include <common/json_escaped.h>
#include <common/json_helpers.h>
#include <common/jsonrpc_errors.h>
#include <common/param.h>
#include <common/pseudorand.h>
#include <common/utils.h>
#include <errno.h>
#include <gossipd/gen_gossip_wire.h>
#include <hsmd/gen_hsm_wire.h>
#include <inttypes.h>
#include <lightningd/channel.h>
#include <lightningd/hsm_control.h>
#include <lightningd/log.h>
#include <lightningd/options.h>
#include <lightningd/peer_control.h>
#include <lightningd/subd.h>
#include <sodium/randombytes.h>
#include <wire/wire_sync.h>

static const char *invoice_status_str(const struct invoice_details *inv)
{
	if (inv->state == PAID)
		return "paid";
	if (inv->state == EXPIRED)
		return "expired";
	return "unpaid";
}

static void json_add_invoice(struct json_stream *response,
			     const struct invoice_details *inv)
{
	json_object_start(response, NULL);
	json_add_escaped_string(response, "label", inv->label);
	json_add_string(response, "bolt11", inv->bolt11);
	json_add_hex(response, "payment_hash", &inv->rhash, sizeof(inv->rhash));
	if (inv->msatoshi)
		json_add_u64(response, "msatoshi", *inv->msatoshi);
	json_add_string(response, "status", invoice_status_str(inv));
	if (inv->state == PAID) {
		json_add_u64(response, "pay_index", inv->pay_index);
		json_add_u64(response, "msatoshi_received",
			     inv->msatoshi_received);
		json_add_u64(response, "paid_at", inv->paid_timestamp);
	}

	if (inv->description)
		json_add_string(response, "description", inv->description);

	json_add_u64(response, "expires_at", inv->expiry_time);

	json_object_end(response);
}

static struct command_result *tell_waiter(struct command *cmd,
					  const struct invoice *inv)
{
	struct json_stream *response;
	const struct invoice_details *details;

	details = wallet_invoice_details(cmd, cmd->ld->wallet, *inv);
	if (details->state == PAID) {
		response = json_stream_success(cmd);
		json_add_invoice(response, details);
		return command_success(cmd, response);
	} else {
		/* FIXME: -2 should be a constant in jsonrpc_errors.h.  */
		response = json_stream_fail(cmd, -2,
					    "invoice expired during wait");
		json_add_invoice(response, details);
		return command_failed(cmd, response);
	}
}

static void tell_waiter_deleted(struct command *cmd)
{
	was_pending(command_fail(cmd, LIGHTNINGD,
				 "Invoice deleted during wait"));
}
static void wait_on_invoice(const struct invoice *invoice, void *cmd)
{
	if (invoice)
		tell_waiter((struct command *) cmd, invoice);
	else
		tell_waiter_deleted((struct command *) cmd);
}

static bool hsm_sign_b11(const u5 *u5bytes,
			 const u8 *hrpu8,
			 secp256k1_ecdsa_recoverable_signature *rsig,
			 struct lightningd *ld)
{
	u8 *msg = towire_hsm_sign_invoice(NULL, u5bytes, hrpu8);

	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_hsm_sign_invoice_reply(msg, rsig))
		fatal("HSM gave bad sign_invoice_reply %s",
		      tal_hex(msg, msg));

	return true;
}

static struct command_result *parse_fallback(struct command *cmd,
					     const char *buffer,
					     const jsmntok_t *fallback,
					     const u8 **fallback_script)

{
	enum address_parse_result fallback_parse;

	fallback_parse
		= json_tok_address_scriptpubkey(cmd,
						get_chainparams(cmd->ld),
						buffer, fallback,
						fallback_script);
	if (fallback_parse == ADDRESS_PARSE_UNRECOGNIZED) {
		return command_fail(cmd, LIGHTNINGD,
				    "Fallback address not valid");
	} else if (fallback_parse == ADDRESS_PARSE_WRONG_NETWORK) {
		return command_fail(cmd, LIGHTNINGD,
				    "Fallback address does not match our network %s",
				    get_chainparams(cmd->ld)->network_name);
	}
	return NULL;
}

/* BOLT11 struct wants an array of arrays (can provide multiple routes) */
static struct route_info **select_inchan(const tal_t *ctx,
					 struct lightningd *ld,
					 u64 capacity_needed,
					 const struct route_info *inchans,
					 bool *any_offline)
{
	const struct route_info *r = NULL;
	struct route_info **ret;

	*any_offline = false;

	/* Weighted reservoir sampling.
	 * Based on https://en.wikipedia.org/wiki/Reservoir_sampling
	 *	 Algorithm A-Chao
	 */
	u64 wsum = 0;
	for (size_t i = 0; i < tal_count(inchans); i++) {
		struct peer *peer;
		struct channel *c;
		u64 msatoshi_avail;

		/* Do we know about this peer? */
		peer = peer_by_id(ld, &inchans[i].pubkey);
		if (!peer)
			continue;

		/* Does it have a channel in state CHANNELD_NORMAL */
		c = peer_normal_channel(peer);
		if (!c)
			continue;

		/* Does it have sufficient capacity. */
		msatoshi_avail = c->funding_satoshi * 1000 - c->our_msatoshi;

		/* Even after reserve taken into account */
		if (c->our_config.channel_reserve_satoshis * 1000
		    > msatoshi_avail)
			continue;

		msatoshi_avail -= c->our_config.channel_reserve_satoshis * 1000;
		if (msatoshi_avail < capacity_needed)
			continue;

		/* Is it offline? */
		if (c->owner == NULL) {
			*any_offline = true;
			continue;
		}

		/* Avoid divide-by-zero corner case. */
		wsum += (msatoshi_avail - capacity_needed + 1);
		if (pseudorand(1ULL << 32)
		    <= ((msatoshi_avail - capacity_needed + 1) << 32) / wsum)
			r = &inchans[i];
	}

	if (!r)
		return NULL;

	ret = tal_arr(ctx, struct route_info *, 1);
	ret[0] = tal_dup(ret, struct route_info, r);
	return ret;
}

/* Encapsulating struct while we wait for gossipd to give us incoming channels */
struct invoice_info {
	struct command *cmd;
	struct preimage payment_preimage;
	struct bolt11 *b11;
	struct json_escaped *label;
};

static void gossipd_incoming_channels_reply(struct subd *gossipd,
					    const u8 *msg,
					    const int *fs,
					    struct invoice_info *info)
{
	struct json_stream *response;
	struct route_info *inchans;
	bool any_offline;
	struct invoice invoice;
	char *b11enc;
	const struct invoice_details *details;
	struct wallet *wallet = info->cmd->ld->wallet;

	if (!fromwire_gossip_get_incoming_channels_reply(tmpctx, msg, &inchans))
		fatal("Gossip gave bad GOSSIP_GET_INCOMING_CHANNELS_REPLY %s",
		      tal_hex(msg, msg));

#if DEVELOPER
	/* dev-routes overrides this. */
	if (!info->b11->routes)
#endif
	info->b11->routes
		= select_inchan(info->b11,
				info->cmd->ld,
				info->b11->msatoshi ? *info->b11->msatoshi : 1,
				inchans,
				&any_offline);

	/* FIXME: add private routes if necessary! */
	b11enc = bolt11_encode(info, info->b11, false,
			       hsm_sign_b11, info->cmd->ld);

	/* Check duplicate preimage (unlikely unless they specified it!) */
	if (wallet_invoice_find_by_rhash(wallet,
					 &invoice, &info->b11->payment_hash)) {
		was_pending(command_fail(info->cmd,
					 INVOICE_PREIMAGE_ALREADY_EXISTS,
					 "preimage already used"));
		return;
	}

	if (!wallet_invoice_create(wallet,
				   &invoice,
				   info->b11->msatoshi,
				   info->label,
				   info->b11->expiry,
				   b11enc,
				   info->b11->description,
				   &info->payment_preimage,
				   &info->b11->payment_hash)) {
		was_pending(command_fail(info->cmd, INVOICE_LABEL_ALREADY_EXISTS,
					 "Duplicate label '%s'",
					 info->label->s));
		return;
	}

	/* Get details */
	details = wallet_invoice_details(info, wallet, invoice);

	response = json_stream_success(info->cmd);
	json_object_start(response, NULL);
	json_add_hex(response, "payment_hash", details->rhash.u.u8,
		     sizeof(details->rhash));
	json_add_u64(response, "expires_at", details->expiry_time);
	json_add_string(response, "bolt11", details->bolt11);

	/* Warn if there's not sufficient incoming capacity. */
	if (tal_count(info->b11->routes) == 0) {
		log_unusual(info->cmd->ld->log,
			    "invoice: insufficient incoming capacity for %"PRIu64
			    " msatoshis%s",
			    info->b11->msatoshi ? *info->b11->msatoshi : 0,
			    any_offline
			    ? " (among currently connected peers)" : "");

		if (any_offline)
			json_add_string(response, "warning_offline",
					"No peers with sufficient"
					" incoming capacity are connected");
		else
			json_add_string(response, "warning_capacity",
					"No channels have sufficient"
					" incoming capacity");
	}
	json_object_end(response);

	was_pending(command_success(info->cmd, response));
}

#if DEVELOPER
/* Since this is a dev-only option, we will crash if dev-routes is not
 * an array-of-arrays-of-correct-items. */
static struct route_info *unpack_route(const tal_t *ctx,
				       const char *buffer,
				       const jsmntok_t *routetok)
{
	const jsmntok_t *t;
	size_t i;
	struct route_info *route = tal_arr(ctx, struct route_info, routetok->size);

	json_for_each_arr(i, t, routetok) {
		const jsmntok_t *pubkey, *fee_base, *fee_prop, *scid, *cltv;
		struct route_info *r = &route[i];
		u32 cltv_u32;

		pubkey = json_get_member(buffer, t, "id");
		scid = json_get_member(buffer, t, "short_channel_id");
		fee_base = json_get_member(buffer, t, "fee_base_msat");
		fee_prop = json_get_member(buffer, t,
					   "fee_proportional_millionths");
		cltv = json_get_member(buffer, t, "cltv_expiry_delta");

		if (!json_to_pubkey(buffer, pubkey, &r->pubkey)
		    || !json_to_short_channel_id(buffer, scid,
						 &r->short_channel_id)
		    || !json_to_number(buffer, fee_base, &r->fee_base_msat)
		    || !json_to_number(buffer, fee_prop,
				       &r->fee_proportional_millionths)
		    || !json_to_number(buffer, cltv, &cltv_u32))
			abort();
		/* We don't have a json_to_u16 */
		r->cltv_expiry_delta = cltv_u32;
	}
	return route;
}

static struct route_info **unpack_routes(const tal_t *ctx,
					 const char *buffer,
					 const jsmntok_t *routestok)
{
	struct route_info **routes;
	const jsmntok_t *t;
	size_t i;

	if (!routestok)
		return NULL;

	routes = tal_arr(ctx, struct route_info *, routestok->size);
	json_for_each_arr(i, t, routestok)
		routes[i] = unpack_route(routes, buffer, t);

	return routes;
}
#endif /* DEVELOPER */

static struct command_result *json_invoice(struct command *cmd,
					   const char *buffer,
					   const jsmntok_t *obj UNNEEDED,
					   const jsmntok_t *params)
{
	const jsmntok_t *fallbacks;
	const jsmntok_t *preimagetok;
	u64 *msatoshi_val;
	struct invoice_info *info;
	const char *desc_val;
	const u8 **fallback_scripts = NULL;
	u64 *expiry;
	struct sha256 rhash;
	bool *exposeprivate;
	const struct chainparams *chainparams;
#if DEVELOPER
	const jsmntok_t *routes;
#endif

	info = tal(cmd, struct invoice_info);
	info->cmd = cmd;

	if (!param(cmd, buffer, params,
		   p_req("msatoshi", param_msat, &msatoshi_val),
		   p_req("label", param_label, &info->label),
		   p_req("description", param_escaped_string, &desc_val),
		   p_opt_def("expiry", param_u64, &expiry, 3600),
		   p_opt("fallbacks", param_array, &fallbacks),
		   p_opt("preimage", param_tok, &preimagetok),
		   p_opt("exposeprivatechannels", param_bool, &exposeprivate),
#if DEVELOPER
		   p_opt("dev-routes", param_array, &routes),
#endif
		   NULL))
		return command_param_failed();

	if (strlen(info->label->s) > INVOICE_MAX_LABEL_LEN) {
		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
				    "Label '%s' over %u bytes", info->label->s,
				    INVOICE_MAX_LABEL_LEN);
	}

	if (strlen(desc_val) >= BOLT11_FIELD_BYTE_LIMIT) {
		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
				    "Descriptions greater than %d bytes "
				    "not yet supported "
				    "(description length %zu)",
				    BOLT11_FIELD_BYTE_LIMIT,
				    strlen(desc_val));
	}

	chainparams = get_chainparams(cmd->ld);
	if (msatoshi_val && *msatoshi_val > chainparams->max_payment_msat) {
		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
				    "msatoshi cannot exceed %"PRIu64
				    " millisatoshis",
				    chainparams->max_payment_msat);
	}

	if (fallbacks) {
		size_t i;
		const jsmntok_t *t;

		fallback_scripts = tal_arr(cmd, const u8 *, fallbacks->size);
		json_for_each_arr(i, t, fallbacks) {
			struct command_result *r;

			r = parse_fallback(cmd, buffer, t, &fallback_scripts[i]);
			if (r)
				return r;
		}
	}

	if (preimagetok) {
		/* Get secret preimage from user. */
		if (!hex_decode(buffer + preimagetok->start,
				preimagetok->end - preimagetok->start,
				&info->payment_preimage,
				sizeof(info->payment_preimage))) {
			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
					    "preimage must be 64 hex digits");
		}
	} else
		/* Generate random secret preimage. */
		randombytes_buf(&info->payment_preimage,
				sizeof(info->payment_preimage));
	/* Generate preimage hash. */
	sha256(&rhash, &info->payment_preimage, sizeof(info->payment_preimage));

	/* Construct bolt11 string. */
	info->b11 = new_bolt11(info, msatoshi_val);
	info->b11->chain = chainparams;
	info->b11->timestamp = time_now().ts.tv_sec;
	info->b11->payment_hash = rhash;
	info->b11->receiver_id = cmd->ld->id;
	info->b11->min_final_cltv_expiry = cmd->ld->config.cltv_final;
	info->b11->expiry = *expiry;
	info->b11->description = tal_steal(info->b11, desc_val);
	info->b11->description_hash = NULL;

#if DEVELOPER
	info->b11->routes = unpack_routes(info->b11, buffer, routes);
#endif
	if (fallback_scripts)
		info->b11->fallbacks = tal_steal(info->b11, fallback_scripts);

	log_debug(cmd->ld->log, "exposeprivate = %s",
		  exposeprivate ? (*exposeprivate ? "TRUE" : "FALSE") : "NULL");
	subd_req(cmd, cmd->ld->gossip,
		 take(towire_gossip_get_incoming_channels(NULL, exposeprivate)),
		 -1, 0, gossipd_incoming_channels_reply, info);

	return command_still_pending(cmd);
}

static const struct json_command invoice_command = {
    "invoice", json_invoice, "Create an invoice for {msatoshi} with {label} "
			     "and {description} with optional {expiry} seconds "
			     "(default 1 hour), optional {fallbacks} address list"
                             "(default empty list) and optional {preimage} "
			     "(default autogenerated)"};
AUTODATA(json_command, &invoice_command);

static void json_add_invoices(struct json_stream *response,
			      struct wallet *wallet,
			      const struct json_escaped *label)
{
	struct invoice_iterator it;
	const struct invoice_details *details;

	/* Don't iterate entire db if we're just after one. */
	if (label) {
		struct invoice invoice;
		if (wallet_invoice_find_by_label(wallet, &invoice, label)) {
			details = wallet_invoice_details(response, wallet, invoice);
			json_add_invoice(response, details);
		}
		return;
	}

	memset(&it, 0, sizeof(it));
	while (wallet_invoice_iterate(wallet, &it)) {
		details = wallet_invoice_iterator_deref(response, wallet, &it);
		json_add_invoice(response, details);
	}
}

static struct command_result *json_listinvoices(struct command *cmd,
						const char *buffer,
						const jsmntok_t *obj UNNEEDED,
						const jsmntok_t *params)
{
	struct json_escaped *label;
	struct json_stream *response;
	struct wallet *wallet = cmd->ld->wallet;
	if (!param(cmd, buffer, params,
		   p_opt("label", param_label, &label),
		   NULL))
		return command_param_failed();
	response = json_stream_success(cmd);
	json_object_start(response, NULL);
	json_array_start(response, "invoices");
	json_add_invoices(response, wallet, label);
	json_array_end(response);
	json_object_end(response);
	return command_success(cmd, response);
}

static const struct json_command listinvoices_command = {
	"listinvoices",
	json_listinvoices,
	"Show invoice {label} (or all, if no {label})"
};
AUTODATA(json_command, &listinvoices_command);

static struct command_result *json_delinvoice(struct command *cmd,
					      const char *buffer,
					      const jsmntok_t *obj UNNEEDED,
					      const jsmntok_t *params)
{
	struct invoice i;
	const struct invoice_details *details;
	struct json_stream *response;
	const char *status, *actual_status;
	struct json_escaped *label;
	struct wallet *wallet = cmd->ld->wallet;

	if (!param(cmd, buffer, params,
		   p_req("label", param_label, &label),
		   p_req("status", param_string, &status),
		   NULL))
		return command_param_failed();

	if (!wallet_invoice_find_by_label(wallet, &i, label)) {
		return command_fail(cmd, LIGHTNINGD, "Unknown invoice");
	}

	details = wallet_invoice_details(cmd, cmd->ld->wallet, i);

	/* This is time-sensitive, so only call once; otherwise error msg
	 * might not make sense if it changed! */
	actual_status = invoice_status_str(details);
	if (!streq(actual_status, status)) {
		return command_fail(cmd, LIGHTNINGD,
				    "Invoice status is %s not %s",
				    actual_status, status);
	}

	if (!wallet_invoice_delete(wallet, i)) {
		log_broken(cmd->ld->log,
			   "Error attempting to remove invoice %"PRIu64,
			   i.id);
		return command_fail(cmd, LIGHTNINGD, "Database error");
	}

	response = json_stream_success(cmd);
	json_add_invoice(response, details);
	return command_success(cmd, response);
}

static const struct json_command delinvoice_command = {
	"delinvoice",
	json_delinvoice,
	"Delete unpaid invoice {label} with {status}",
};
AUTODATA(json_command, &delinvoice_command);

static struct command_result *json_delexpiredinvoice(struct command *cmd,
						     const char *buffer,
						     const jsmntok_t *obj UNNEEDED,
						     const jsmntok_t *params)
{
	u64 *maxexpirytime;

	if (!param(cmd, buffer, params,
		   p_opt_def("maxexpirytime", param_u64, &maxexpirytime,
				 time_now().ts.tv_sec),
		   NULL))
		return command_param_failed();

	wallet_invoice_delete_expired(cmd->ld->wallet, *maxexpirytime);

	return command_success(cmd, null_response(cmd));
}
static const struct json_command delexpiredinvoice_command = {
	"delexpiredinvoice",
	json_delexpiredinvoice,
	"Delete all expired invoices that expired as of given {maxexpirytime} (a UNIX epoch time), or all expired invoices if not specified"
};
AUTODATA(json_command, &delexpiredinvoice_command);

static struct command_result *json_autocleaninvoice(struct command *cmd,
						    const char *buffer,
						    const jsmntok_t *obj UNNEEDED,
						    const jsmntok_t *params)
{
	u64 *cycle;
	u64 *exby;

	if (!param(cmd, buffer, params,
		   p_opt_def("cycle_seconds", param_u64, &cycle, 3600),
		   p_opt_def("expired_by", param_u64, &exby, 86400),
		   NULL))
		return command_param_failed();

	wallet_invoice_autoclean(cmd->ld->wallet, *cycle, *exby);

	return command_success(cmd, null_response(cmd));
}
static const struct json_command autocleaninvoice_command = {
	"autocleaninvoice",
	json_autocleaninvoice,
	"Set up autoclean of expired invoices. "
	"Perform cleanup every {cycle_seconds} (default 3600), or disable autoclean if 0. "
	"Clean up expired invoices that have expired for {expired_by} seconds (default 86400). "
};
AUTODATA(json_command, &autocleaninvoice_command);

static struct command_result *json_waitanyinvoice(struct command *cmd,
						  const char *buffer,
						  const jsmntok_t *obj UNNEEDED,
						  const jsmntok_t *params)
{
	u64 *pay_index;
	struct wallet *wallet = cmd->ld->wallet;

	if (!param(cmd, buffer, params,
		   p_opt_def("lastpay_index", param_u64, &pay_index, 0),
		   NULL))
		return command_param_failed();

	/* Set command as pending. We do not know if
	 * wallet_invoice_waitany will return immediately
	 * or not, so indicating pending is safest.  */
	fixme_ignore(command_still_pending(cmd));

	/* Find next paid invoice. */
	wallet_invoice_waitany(cmd, wallet, *pay_index,
			       &wait_on_invoice, (void*) cmd);

	return command_its_complicated("wallet_invoice_waitany might complete"
				       " immediately, but we also call it as a"
				       " callback so plumbing through the return"
				       " is non-trivial.");
}

static const struct json_command waitanyinvoice_command = {
	"waitanyinvoice",
	json_waitanyinvoice,
	"Wait for the next invoice to be paid, after {lastpay_index} (if supplied)"
};
AUTODATA(json_command, &waitanyinvoice_command);


/* Wait for an incoming payment matching the `label` in the JSON
 * command.  This will either return immediately if the payment has
 * already been received or it may add the `cmd` to the list of
 * waiters, if the payment is still pending.
 */
static struct command_result *json_waitinvoice(struct command *cmd,
					       const char *buffer,
					       const jsmntok_t *obj UNNEEDED,
					       const jsmntok_t *params)
{
	struct invoice i;
	const struct invoice_details *details;
	struct wallet *wallet = cmd->ld->wallet;
	struct json_escaped *label;

	if (!param(cmd, buffer, params,
		   p_req("label", param_label, &label),
		   NULL))
		return command_param_failed();

	if (!wallet_invoice_find_by_label(wallet, &i, label)) {
		return command_fail(cmd, LIGHTNINGD, "Label not found");
	}
	details = wallet_invoice_details(cmd, cmd->ld->wallet, i);

	/* If paid or expired return immediately */
	if (details->state == PAID || details->state == EXPIRED) {
		return tell_waiter(cmd, &i);
	} else {
		/* There is an unpaid one matching, let's wait... */
		fixme_ignore(command_still_pending(cmd));
		wallet_invoice_waitone(cmd, wallet, i,
				       &wait_on_invoice, (void *) cmd);
		return command_its_complicated("wallet_invoice_waitone might"
					       " complete immediately");
	}
}

static const struct json_command waitinvoice_command = {
	"waitinvoice",
	json_waitinvoice,
	"Wait for an incoming payment matching the invoice with {label}, or if the invoice expires"
};
AUTODATA(json_command, &waitinvoice_command);

static void json_add_fallback(struct json_stream *response,
			      const char *fieldname,
			      const u8 *fallback,
			      const struct chainparams *chain)
{
	struct bitcoin_address pkh;
	struct ripemd160 sh;
	struct sha256 wsh;

	json_object_start(response, fieldname);
	if (is_p2pkh(fallback, &pkh)) {
		json_add_string(response, "type", "P2PKH");
		json_add_string(response, "addr",
				bitcoin_to_base58(tmpctx, chain->testnet, &pkh));
	} else if (is_p2sh(fallback, &sh)) {
		json_add_string(response, "type", "P2SH");
		json_add_string(response, "addr",
				p2sh_to_base58(tmpctx, chain->testnet, &sh));
	} else if (is_p2wpkh(fallback, &pkh)) {
		char out[73 + strlen(chain->bip173_name)];
		json_add_string(response, "type", "P2WPKH");
		if (segwit_addr_encode(out, chain->bip173_name, 0,
				       (const u8 *)&pkh, sizeof(pkh)))
			json_add_string(response, "addr", out);
	} else if (is_p2wsh(fallback, &wsh)) {
		char out[73 + strlen(chain->bip173_name)];
		json_add_string(response, "type", "P2WSH");
		if (segwit_addr_encode(out, chain->bip173_name, 0,
				       (const u8 *)&wsh, sizeof(wsh)))
			json_add_string(response, "addr", out);
	}
	json_add_hex_talarr(response, "hex", fallback);
	json_object_end(response);
}

static struct command_result *json_decodepay(struct command *cmd,
					     const char *buffer,
					     const jsmntok_t *obj UNNEEDED,
					     const jsmntok_t *params)
{
	struct bolt11 *b11;
	struct json_stream *response;
	const char *str, *desc;
	char *fail;

	if (!param(cmd, buffer, params,
		   p_req("bolt11", param_string, &str),
		   p_opt("description", param_string, &desc),
		   NULL))
		return command_param_failed();

	b11 = bolt11_decode(cmd, str, desc, &fail);

	if (!b11) {
		return command_fail(cmd, LIGHTNINGD, "Invalid bolt11: %s", fail);
	}

	response = json_stream_success(cmd);
	json_object_start(response, NULL);

	json_add_string(response, "currency", b11->chain->bip173_name);
	json_add_u64(response, "created_at", b11->timestamp);
	json_add_u64(response, "expiry", b11->expiry);
	json_add_pubkey(response, "payee", &b11->receiver_id);
        if (b11->msatoshi)
                json_add_u64(response, "msatoshi", *b11->msatoshi);
        if (b11->description) {
		struct json_escaped *esc = json_escape(NULL, b11->description);
                json_add_escaped_string(response, "description", take(esc));
	}
        if (b11->description_hash)
                json_add_hex(response, "description_hash",
                             b11->description_hash,
                             sizeof(*b11->description_hash));
	json_add_num(response, "min_final_cltv_expiry",
		     b11->min_final_cltv_expiry);
        if (tal_count(b11->fallbacks)) {
		json_array_start(response, "fallbacks");
		for (size_t i = 0; i < tal_count(b11->fallbacks); i++)
			json_add_fallback(response, NULL,
					  b11->fallbacks[i], b11->chain);
		json_array_end(response);
        }

        if (tal_count(b11->routes)) {
                size_t i, n;

                json_array_start(response, "routes");
                for (i = 0; i < tal_count(b11->routes); i++) {
                        json_array_start(response, NULL);
                        for (n = 0; n < tal_count(b11->routes[i]); n++) {
                                json_object_start(response, NULL);
                                json_add_pubkey(response, "pubkey",
                                                &b11->routes[i][n].pubkey);
                                json_add_short_channel_id(response,
                                                          "short_channel_id",
                                                          &b11->routes[i][n]
                                                          .short_channel_id);
                                json_add_u64(response, "fee_base_msat",
                                             b11->routes[i][n].fee_base_msat);
                                json_add_u64(response, "fee_proportional_millionths",
                                             b11->routes[i][n].fee_proportional_millionths);
                                json_add_num(response, "cltv_expiry_delta",
                                             b11->routes[i][n]
                                             .cltv_expiry_delta);
                                json_object_end(response);
                        }
                        json_array_end(response);
                }
                json_array_end(response);
        }

        if (!list_empty(&b11->extra_fields)) {
                struct bolt11_field *extra;

                json_array_start(response, "extra");
                list_for_each(&b11->extra_fields, extra, list) {
                        char *data = tal_arr(cmd, char, tal_count(extra->data)+1);
                        size_t i;

                        for (i = 0; i < tal_count(extra->data); i++)
                                data[i] = bech32_charset[extra->data[i]];
                        data[i] = '\0';
                        json_object_start(response, NULL);
                        json_add_string(response, "tag",
                                        tal_fmt(data, "%c", extra->tag));
                        json_add_string(response, "data", data);
                        tal_free(data);
                        json_object_end(response);
                }
                json_array_end(response);
        }

	json_add_hex(response, "payment_hash",
                     &b11->payment_hash, sizeof(b11->payment_hash));

	json_add_string(response, "signature",
                        type_to_string(cmd, secp256k1_ecdsa_signature,
                                       &b11->sig));
	json_object_end(response);
	return command_success(cmd, response);
}

static const struct json_command decodepay_command = {
	"decodepay",
	json_decodepay,
	"Decode {bolt11}, using {description} if necessary"
};
AUTODATA(json_command, &decodepay_command);