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#include <bitcoin/chainparams.h>
#include <bitcoin/preimage.h>
#include <ccan/cast/cast.h>
#include <ccan/mem/mem.h>
#include <common/bech32_util.h>
#include <common/bolt12.h>
#include <common/bolt12_merkle.h>
#include <common/json_stream.h>
#include <common/overflows.h>
#include <common/type_to_string.h>
#include <plugins/offers.h>
#include <plugins/offers_inv_hook.h>
#include <secp256k1_schnorrsig.h>
/* We need to keep the reply path around so we can reply if error */
struct inv {
struct tlv_invoice *inv;
const char *buf;
/* May be NULL */
const jsmntok_t *replytok;
/* The offer, once we've looked it up. */
struct tlv_offer *offer;
};
static struct command_result *WARN_UNUSED_RESULT
fail_inv_level(struct command *cmd,
const struct inv *inv,
enum log_level l,
const char *fmt, va_list ap)
{
char *full_fmt, *msg;
struct tlv_invoice_error *err;
u8 *errdata;
full_fmt = tal_fmt(tmpctx, "Failed invoice %s",
invoice_encode(tmpctx, inv->inv));
if (inv->inv->offer_id)
tal_append_fmt(&full_fmt, " for offer %s",
type_to_string(tmpctx, struct sha256,
inv->inv->offer_id));
tal_append_fmt(&full_fmt, ": %s", fmt);
msg = tal_vfmt(tmpctx, full_fmt, ap);
plugin_log(cmd->plugin, l, "%s", msg);
/* Only reply if they gave us a path */
if (!inv->replytok)
return command_hook_success(cmd);
/* Don't send back internal error details. */
if (l == LOG_BROKEN)
msg = "Internal error";
err = tlv_invoice_error_new(cmd);
/* Remove NUL terminator */
err->error = tal_dup_arr(err, char, msg, strlen(msg), 0);
/* FIXME: Add suggested_value / erroneous_field! */
errdata = tal_arr(cmd, u8, 0);
towire_invoice_error(&errdata, err);
return send_onion_reply(cmd, inv->buf, inv->replytok, "invoice_error", errdata);
}
static struct command_result *WARN_UNUSED_RESULT
fail_inv(struct command *cmd,
const struct inv *inv,
const char *fmt, ...)
{
va_list ap;
struct command_result *ret;
va_start(ap, fmt);
ret = fail_inv_level(cmd, inv, LOG_DBG, fmt, ap);
va_end(ap);
return ret;
}
static struct command_result *WARN_UNUSED_RESULT
fail_internalerr(struct command *cmd,
const struct inv *inv,
const char *fmt, ...)
{
va_list ap;
struct command_result *ret;
va_start(ap, fmt);
ret = fail_inv_level(cmd, inv, LOG_BROKEN, fmt, ap);
va_end(ap);
return ret;
}
#define inv_must_have(cmd_, i_, fld_) \
test_field(cmd_, i_, i_->inv->fld_ != NULL, #fld_, "missing")
#define inv_must_not_have(cmd_, i_, fld_) \
test_field(cmd_, i_, i_->inv->fld_ == NULL, #fld_, "unexpected")
#define inv_must_equal_offer(cmd_, i_, fld_) \
test_field_eq(cmd_, i_, i_->inv->fld_, i_->offer->fld_, #fld_)
static struct command_result *
test_field(struct command *cmd,
const struct inv *inv,
bool test, const char *fieldname, const char *what)
{
if (!test)
return fail_inv(cmd, inv, "%s %s", what, fieldname);
return NULL;
}
static struct command_result *
test_field_eq(struct command *cmd,
const struct inv *inv,
const tal_t *invfield,
const tal_t *offerfield,
const char *fieldname)
{
if (invfield && !offerfield)
return fail_inv(cmd, inv, "Unexpected %s", fieldname);
if (!invfield && offerfield)
return fail_inv(cmd, inv, "Expected %s", fieldname);
if (!memeq(invfield, tal_bytelen(invfield),
offerfield, tal_bytelen(offerfield)))
return fail_inv(cmd, inv, "Different %s", fieldname);
return NULL;
}
static struct command_result *pay_done(struct command *cmd,
const char *buf,
const jsmntok_t *result,
struct inv *inv)
{
struct amount_msat msat = amount_msat(*inv->inv->amount);
plugin_log(cmd->plugin, LOG_INFORM,
"Payed out %s for offer %s%s: %.*s",
type_to_string(tmpctx, struct amount_msat, &msat),
type_to_string(tmpctx, struct sha256, inv->inv->offer_id),
inv->offer->refund_for ? " (refund)": "",
json_tok_full_len(result),
json_tok_full(buf, result));
return command_hook_success(cmd);
}
static struct command_result *pay_error(struct command *cmd,
const char *buf,
const jsmntok_t *error,
struct inv *inv)
{
const jsmntok_t *msgtok = json_get_member(buf, error, "message");
return fail_inv(cmd, inv, "pay attempt failed: %.*s",
json_tok_full_len(msgtok),
json_tok_full(buf, msgtok));
}
static struct command_result *listoffers_done(struct command *cmd,
const char *buf,
const jsmntok_t *result,
struct inv *inv)
{
const jsmntok_t *arr = json_get_member(buf, result, "offers");
const jsmntok_t *offertok, *activetok, *b12tok;
bool active;
struct amount_msat amt;
char *fail;
struct out_req *req;
struct command_result *err;
/* BOLT-offers #12:
* - otherwise if `offer_id` is set:
* - MUST reject the invoice if the `offer_id` does not refer an
* unexpired offer with `send_invoice`
*/
if (arr->size == 0)
return fail_inv(cmd, inv, "Unknown offer");
plugin_log(cmd->plugin, LOG_INFORM,
"Attempting payment of offer %.*s",
json_tok_full_len(result),
json_tok_full(buf, result));
offertok = arr + 1;
activetok = json_get_member(buf, offertok, "active");
if (!activetok) {
return fail_internalerr(cmd, inv,
"Missing active: %.*s",
json_tok_full_len(offertok),
json_tok_full(buf, offertok));
}
json_to_bool(buf, activetok, &active);
if (!active)
return fail_inv(cmd, inv, "Offer no longer available");
b12tok = json_get_member(buf, offertok, "bolt12");
if (!b12tok) {
return fail_internalerr(cmd, inv,
"Missing bolt12: %.*s",
json_tok_full_len(offertok),
json_tok_full(buf, offertok));
}
inv->offer = offer_decode(inv,
buf + b12tok->start,
b12tok->end - b12tok->start,
plugin_feature_set(cmd->plugin),
chainparams, &fail);
if (!inv->offer) {
return fail_internalerr(cmd, inv,
"Invalid offer: %s (%.*s)",
fail,
json_tok_full_len(offertok),
json_tok_full(buf, offertok));
}
if (inv->offer->absolute_expiry
&& time_now().ts.tv_sec >= *inv->offer->absolute_expiry) {
/* FIXME: do deloffer to disable it */
return fail_inv(cmd, inv, "Offer expired");
}
if (!inv->offer->send_invoice) {
return fail_inv(cmd, inv, "Offer did not expect invoice");
}
/* BOLT-offers #12:
* - MUST reject the invoice unless the following fields are equal
* or unset exactly as they are in the `offer`:
* - `refund_for`
* - `description`
* - `vendor`
*/
err = inv_must_equal_offer(cmd, inv, refund_for);
if (err)
return err;
err = inv_must_equal_offer(cmd, inv, description);
if (err)
return err;
err = inv_must_equal_offer(cmd, inv, vendor);
if (err)
return err;
/* BOLT-offers #12:
* - if the offer had a `quantity_min` or `quantity_max` field:
* - MUST fail the request if there is no `quantity` field.
* - MUST fail the request if there is `quantity` is not within
* that (inclusive) range.
* - otherwise:
* - MUST fail the request if there is a `quantity` field.
*/
if (inv->offer->quantity_min || inv->offer->quantity_max) {
err = inv_must_have(cmd, inv, quantity);
if (err)
return err;
if (inv->offer->quantity_min &&
*inv->inv->quantity < *inv->offer->quantity_min) {
return fail_inv(cmd, inv,
"quantity %"PRIu64 " < %"PRIu64,
*inv->inv->quantity,
*inv->offer->quantity_min);
}
if (inv->offer->quantity_max &&
*inv->inv->quantity > *inv->offer->quantity_max) {
return fail_inv(cmd, inv,
"quantity %"PRIu64" > %"PRIu64,
*inv->inv->quantity,
*inv->offer->quantity_max);
}
} else {
err = inv_must_not_have(cmd, inv, quantity);
if (err)
return err;
}
/* BOLT-offers #12:
* - MUST reject the invoice if `msat` is not present.
*/
err = inv_must_have(cmd, inv, amount);
if (err)
return err;
/* FIXME: Handle alternate currency conversion here! */
if (inv->offer->currency)
return fail_inv(cmd, inv, "FIXME: support currency");
amt = amount_msat(*inv->inv->amount);
/* If you send an offer without an amount, you want to give away
* unlimited money. Err, ok? */
if (inv->offer->amount) {
struct amount_msat expected = amount_msat(*inv->offer->amount);
/* We could allow invoices for less, I suppose. */
if (!amount_msat_eq(expected, amt))
return fail_inv(cmd, inv, "Expected invoice for %s",
fmt_amount_msat(tmpctx, expected));
}
plugin_log(cmd->plugin, LOG_INFORM,
"Attempting payment of %s for offer %s%s",
type_to_string(tmpctx, struct amount_msat, &amt),
type_to_string(tmpctx, struct sha256, inv->inv->offer_id),
inv->offer->refund_for ? " (refund)": "");
req = jsonrpc_request_start(cmd->plugin, cmd, "pay",
pay_done, pay_error, inv);
json_add_string(req->js, "bolt11", invoice_encode(tmpctx, inv->inv));
json_add_sha256(req->js, "localofferid", inv->inv->offer_id);
return send_outreq(cmd->plugin, req);
}
static struct command_result *listoffers_error(struct command *cmd,
const char *buf,
const jsmntok_t *err,
struct inv *inv)
{
return fail_internalerr(cmd, inv,
"listoffers gave JSON error: %.*s",
json_tok_full_len(err),
json_tok_full(buf, err));
}
struct command_result *handle_invoice(struct command *cmd,
const char *buf,
const jsmntok_t *invtok,
const jsmntok_t *replytok)
{
const u8 *invbin = json_tok_bin_from_hex(cmd, buf, invtok);
size_t len = tal_count(invbin);
struct inv *inv = tal(cmd, struct inv);
struct out_req *req;
struct command_result *err;
int bad_feature;
struct sha256 m, shash;
/* Make a copy of entire buffer, for later. */
inv->buf = tal_dup_arr(inv, char, buf, replytok->end, 0);
inv->replytok = replytok;
inv->inv = tlv_invoice_new(cmd);
if (!fromwire_invoice(&invbin, &len, inv->inv)) {
return fail_inv(cmd, inv,
"Invalid invoice %s",
tal_hex(tmpctx, invbin));
}
/* BOLT-offers #12:
*
* The reader of an invoice_request:
*...
* - MUST fail the request if `features` contains unknown even bits.
*/
bad_feature = features_unsupported(plugin_feature_set(cmd->plugin),
inv->inv->features,
BOLT11_FEATURE);
if (bad_feature != -1) {
return fail_inv(cmd, inv,
"Unsupported inv feature %i",
bad_feature);
}
/* BOLT-offers #12:
*
* The reader of an invoice_request:
*...
* - MUST fail the request if `chains` does not include (or imply) a
* supported chain.
*/
if (!bolt12_chains_match(inv->inv->chains, chainparams)) {
return fail_inv(cmd, inv,
"Wrong chains %s",
tal_hex(tmpctx, inv->inv->chains));
}
/* BOLT-offers #12:
* - MUST reject the invoice if `signature` is not a valid signature
* using `node_id` as described in
* [Signature Calculation](#signature-calculation).
*/
err = inv_must_have(cmd, inv, node_id);
if (err)
return err;
err = inv_must_have(cmd, inv, signature);
if (err)
return err;
merkle_tlv(inv->inv->fields, &m);
sighash_from_merkle("invoice", "signature", &m, &shash);
if (secp256k1_schnorrsig_verify(secp256k1_ctx,
inv->inv->signature->u8,
shash.u.u8,
&inv->inv->node_id->pubkey) != 1) {
return fail_inv(cmd, inv, "Bad signature");
}
/* We don't pay random invoices off the internet, sorry. */
err = inv_must_have(cmd, inv, offer_id);
if (err)
return err;
/* Now find the offer. */
req = jsonrpc_request_start(cmd->plugin, cmd, "listoffers",
listoffers_done, listoffers_error, inv);
json_add_sha256(req->js, "offer_id", inv->inv->offer_id);
return send_outreq(cmd->plugin, req);
}