mirror of
https://github.com/aljazceru/lightning.git
synced 2026-01-05 23:24:21 +01:00
offers: convert currency when they request an invoice.
Means a reshuffle of our logic: we want to multiply by quantity before conversion for maximum accuracy. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
committed by
Christian Decker
Christian Decker
parent
9681d491df
commit
4bb05e46e9
@@ -4,6 +4,7 @@
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#include <common/bech32_util.h>
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#include <common/bolt12.h>
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#include <common/bolt12_merkle.h>
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#include <common/iso4217.h>
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#include <common/json_stream.h>
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#include <common/overflows.h>
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#include <common/type_to_string.h>
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@@ -405,6 +406,170 @@ static bool check_recurrence_sig(const struct tlv_invoice_request *invreq,
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sighash.u.u8, &payer_key->pubkey) == 1;
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}
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static struct command_result *invreq_amount_by_quantity(struct command *cmd,
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const struct invreq *ir,
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u64 *raw_amt)
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{
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struct command_result *err;
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assert(ir->offer->amount);
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/* BOLT-offers #12:
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*
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* - if the offer included `amount`:
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* - MUST fail the request if it contains `amount`.
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*/
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err = invreq_must_not_have(cmd, ir, amount);
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if (err)
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return err;
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*raw_amt = *ir->offer->amount;
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/* BOLT-offers #12:
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* - if request contains `quantity`, multiply by `quantity`.
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*/
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if (ir->invreq->quantity) {
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if (mul_overflows_u64(*ir->invreq->quantity, *raw_amt)) {
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return fail_invreq(cmd, ir,
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"quantity %"PRIu64
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" causes overflow",
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*ir->invreq->quantity);
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}
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*raw_amt *= *ir->invreq->quantity;
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}
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return NULL;
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}
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/* The non-currency-converting case. */
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static struct command_result *invreq_base_amount_simple(struct command *cmd,
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const struct invreq *ir,
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struct amount_msat *amt)
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{
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struct command_result *err;
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if (ir->offer->amount) {
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u64 raw_amount;
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assert(!ir->offer->currency);
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err = invreq_amount_by_quantity(cmd, ir, &raw_amount);
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if (err)
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return err;
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*amt = amount_msat(raw_amount);
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} else {
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/* BOLT-offers #12:
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*
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* - otherwise:
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* - MUST fail the request if it does not contain `amount`.
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* - MUST use the request `amount` as the *base invoice amount*.
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* (Note: invoice amount can be further modiifed by recurrence
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* below)
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*/
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err = invreq_must_have(cmd, ir, amount);
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if (err)
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return err;
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*amt = amount_msat(*ir->invreq->amount);
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}
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return NULL;
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}
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static struct command_result *handle_amount_and_recurrence(struct command *cmd,
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struct invreq *ir,
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struct amount_msat amount)
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{
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ir->inv->amount = tal_dup(ir->inv, u64,
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&amount.millisatoshis); /* Raw: wire protocol */
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/* Last of all, we handle recurrence details, which often requires
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* further lookups. */
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/* BOLT-offers #12:
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* - MUST set (or not set) `recurrence_counter` exactly as the
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* invoice_request did.
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*/
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if (ir->invreq->recurrence_counter) {
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ir->inv->recurrence_counter = ir->invreq->recurrence_counter;
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return check_previous_invoice(cmd, ir);
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}
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/* We're happy with 2 hours timeout (default): they can always
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* request another. */
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/* FIXME: Fallbacks? */
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return create_invoicereq(cmd, ir);
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}
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static struct command_result *currency_done(struct command *cmd,
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const char *buf,
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const jsmntok_t *result,
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struct invreq *ir)
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{
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const jsmntok_t *msat = json_get_member(buf, result, "msat");
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struct amount_msat amount;
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/* Fail in this case, forwarding warnings. */
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if (!msat)
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return fail_internalerr(cmd, ir,
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"Cannot convert currency %.*s: %.*s",
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(int)tal_bytelen(ir->offer->currency),
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(const char *)ir->offer->currency,
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json_tok_full_len(result),
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json_tok_full(buf, result));
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if (!json_to_msat(buf, msat, &amount))
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return fail_internalerr(cmd, ir,
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"Bad convert for currency %.*s: %.*s",
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(int)tal_bytelen(ir->offer->currency),
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(const char *)ir->offer->currency,
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json_tok_full_len(msat),
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json_tok_full(buf, msat));
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return handle_amount_and_recurrence(cmd, ir, amount);
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}
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static struct command_result *convert_currency(struct command *cmd,
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struct invreq *ir)
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{
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struct out_req *req;
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u64 raw_amount;
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double double_amount;
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struct command_result *err;
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const struct iso4217_name_and_divisor *iso4217;
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assert(ir->offer->currency);
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/* Multiply by quantity *first*, for best precision */
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err = invreq_amount_by_quantity(cmd, ir, &raw_amount);
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if (err)
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return err;
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/* BOLT-offers #12:
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* - MUST calculate the *base invoice amount* using the offer
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* `amount`:
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* - if offer `currency` is not the invoice currency, convert
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* to the invoice currency.
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*/
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iso4217 = find_iso4217(ir->offer->currency,
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tal_bytelen(ir->offer->currency));
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/* We should not create offer with unknown currency! */
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if (!iso4217)
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return fail_internalerr(cmd, ir,
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"Unknown offer currency %.*s",
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(int)tal_bytelen(ir->offer->currency),
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ir->offer->currency);
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double_amount = (double)raw_amount;
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for (size_t i = 0; i < iso4217->minor_unit; i++)
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double_amount /= 10;
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req = jsonrpc_request_start(cmd->plugin, cmd, "currencyconvert",
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currency_done, error, ir);
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json_add_stringn(req->js, "currency",
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(const char *)ir->offer->currency,
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tal_bytelen(ir->offer->currency));
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json_add_member(req->js, "amount", false, "%f", double_amount);
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return send_outreq(cmd->plugin, req);
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}
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static struct command_result *listoffers_done(struct command *cmd,
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const char *buf,
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const jsmntok_t *result,
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@@ -413,9 +578,9 @@ static struct command_result *listoffers_done(struct command *cmd,
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const jsmntok_t *arr = json_get_member(buf, result, "offers");
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const jsmntok_t *offertok, *activetok, *b12tok;
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bool active;
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struct amount_msat amt;
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char *fail;
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struct command_result *err;
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struct amount_msat amt;
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/* BOLT-offers #12:
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*
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@@ -498,64 +663,6 @@ static struct command_result *listoffers_done(struct command *cmd,
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return err;
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}
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if (ir->offer->amount) {
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u64 raw_amount;
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/* BOLT-offers #12:
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*
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* - if the offer included `amount`:
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* - MUST fail the request if it contains `amount`.
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*/
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err = invreq_must_not_have(cmd, ir, amount);
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if (err)
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return err;
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/* BOLT-offers #12:
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* - MUST calculate the *base invoice amount* using the offer
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* `amount`:
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* - if offer `currency` is not the invoice currency, convert
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* to the invoice currency.
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*/
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if (ir->offer->currency) {
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/* FIXME: Currency conversion! */
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return fail_invreq(cmd, ir,
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"FIXME: Request for currency %.*s",
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(int)tal_bytelen(ir->offer->currency),
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(char *)ir->offer->currency);
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} else
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raw_amount = *ir->offer->amount;
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/* BOLT-offers #12:
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* - if request contains `quantity`, multiply by `quantity`.
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*/
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if (ir->invreq->quantity) {
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if (mul_overflows_u64(*ir->invreq->quantity, raw_amount)) {
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return fail_invreq(cmd, ir,
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"quantity %"PRIu64
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" causes overflow",
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*ir->invreq->quantity);
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}
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raw_amount *= *ir->invreq->quantity;
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}
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amt = amount_msat(raw_amount);
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} else {
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/* BOLT-offers #12:
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*
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* - otherwise:
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* - MUST fail the request if it does not contain `amount`.
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* - MUST use the request `amount` as the *base invoice amount*.
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* (Note: invoice amount can be further modiifed by recurrence
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* below)
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*/
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err = invreq_must_have(cmd, ir, amount);
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if (err)
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return err;
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amt = amount_msat(*ir->invreq->amount);
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}
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if (ir->offer->recurrence) {
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/* BOLT-offers #12:
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*
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@@ -612,8 +719,6 @@ static struct command_result *listoffers_done(struct command *cmd,
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/* Which is the same as the invreq */
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ir->inv->offer_id = tal_dup(ir->inv, struct sha256,
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ir->invreq->offer_id);
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ir->inv->amount = tal_dup(ir->inv, u64,
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&amt.millisatoshis); /* Raw: wire protocol */
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ir->inv->description = tal_dup_talarr(ir->inv, char,
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ir->offer->description);
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ir->inv->features = tal_dup_talarr(ir->inv, u8,
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@@ -651,23 +756,14 @@ static struct command_result *listoffers_done(struct command *cmd,
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ir->inv->timestamp = tal(ir->inv, u64);
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*ir->inv->timestamp = time_now().ts.tv_sec;
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/* Last of all, we handle recurrence details, which often requires
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* further lookups. */
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/* We may require currency lookup; if so, do it now. */
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if (ir->offer->amount && ir->offer->currency)
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return convert_currency(cmd, ir);
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/* BOLT-offers #12:
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* - MUST set (or not set) `recurrence_counter` exactly as the
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* invoice_request did.
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*/
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if (ir->invreq->recurrence_counter) {
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ir->inv->recurrence_counter = ir->invreq->recurrence_counter;
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return check_previous_invoice(cmd, ir);
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}
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/* We're happy with 2 hours timeout (default): they can always
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* request another. */
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/* FIXME: Fallbacks? */
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/* FIXME: refunds? */
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return create_invoicereq(cmd, ir);
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err = invreq_base_amount_simple(cmd, ir, &amt);
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if (err)
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return err;
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return handle_amount_and_recurrence(cmd, ir, amt);
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}
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static struct command_result *handle_offerless_request(struct command *cmd,
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