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https://github.com/aljazceru/lightning.git
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paymod: Implement keysend sending support as a native RPC command
This makes use of the payment modifier structure to just add the preimage to the TLV payload for the last hop. Changelog-Added: JSON-RPC: The `keysend` command allows sending to a node without requiring an invoice first.
This commit is contained in:
Christian Decker
@@ -2,17 +2,186 @@
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#include <ccan/array_size/array_size.h>
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#include <ccan/tal/str/str.h>
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#include <plugins/libplugin.h>
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#include <plugins/libplugin-pay.h>
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#include <wire/gen_onion_wire.h>
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#define PREIMAGE_TLV_TYPE 5482373484
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#define KEYSEND_FEATUREBIT 55
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static unsigned int maxdelay_default;
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static struct node_id my_id;
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/*****************************************************************************
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* Keysend modifier
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* ================
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*
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* The keysend modifier adds the payment preimage to the TLV payload. This
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* enables the recipient to accept the payment despite it not correspondin to
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* an invoice that the recipient created. Keysend does not provide any proof
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* or payment, but does not require an out-of-band communication round to get
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* an invoice first.
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*/
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/* FIXME: If we have more than one plugin using keysend we can move this to
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* libplugin-pay.c */
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struct keysend_data {
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struct preimage preimage;
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};
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REGISTER_PAYMENT_MODIFIER_HEADER(keysend, struct keysend_data);
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static struct keysend_data *keysend_init(struct payment *p)
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{
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struct keysend_data *d;
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struct sha256 payment_hash;
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if (p->parent == NULL) {
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/* If we are the root payment we generate a random preimage
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* and populate the preimage field in the keysend_data and the
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* payment_hash in the payment. */
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d = tal(p, struct keysend_data);
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randombytes_buf(&d->preimage, sizeof(d->preimage));
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ccan_sha256(&payment_hash, &d->preimage, sizeof(d->preimage));
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p->payment_hash = tal_dup(p, struct sha256, &payment_hash);
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return d;
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} else {
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/* If we are a child payment (retry or split) we copy the
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* parent's information, since the payment_hash needs to match
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* in order to be collated at the recipient. */
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return payment_mod_keysend_get_data(p->parent);
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}
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}
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static void keysend_cb(struct keysend_data *d, struct payment *p) {
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struct route_hop *last_hop;
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struct createonion_hop *last_payload;
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size_t hopcount;
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u8 *raw_preimage;
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if (p->step == PAYMENT_STEP_GOT_ROUTE) {
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/* Force the last step to be a TLV, we might not have an
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* announcement and it still supports it. Required later when
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* we adjust the payload. */
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last_hop = &p->route[tal_count(p->route) - 1];
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last_hop->style = ROUTE_HOP_TLV;
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}
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if (p->step != PAYMENT_STEP_ONION_PAYLOAD)
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return payment_continue(p);
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raw_preimage = tal_dup_arr(p->createonion_request, u8, d->preimage.r,
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sizeof(d->preimage), 0);
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hopcount = tal_count(p->createonion_request->hops);
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last_payload = &p->createonion_request->hops[hopcount - 1];
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tlvstream_set_raw(&last_payload->tlv_payload->fields, PREIMAGE_TLV_TYPE,
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take(raw_preimage));
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return payment_continue(p);
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}
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REGISTER_PAYMENT_MODIFIER(keysend, struct keysend_data *, keysend_init,
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keysend_cb);
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/*
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* End of keysend modifier
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*****************************************************************************/
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static void init(struct plugin *p, const char *buf UNUSED,
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const jsmntok_t *config UNUSED)
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{
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const char *field;
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field = rpc_delve(tmpctx, p, "getinfo",
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take(json_out_obj(NULL, NULL, NULL)), ".id");
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if (!node_id_from_hexstr(field, strlen(field), &my_id))
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plugin_err(p, "getinfo didn't contain valid id: '%s'", field);
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field =
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rpc_delve(tmpctx, p, "listconfigs",
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take(json_out_obj(NULL, "config", "max-locktime-blocks")),
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".max-locktime-blocks");
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maxdelay_default = atoi(field);
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}
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struct payment_modifier *pay_mods[8] = {
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&keysend_pay_mod,
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&local_channel_hints_pay_mod,
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&directpay_pay_mod,
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&shadowroute_pay_mod,
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&exemptfee_pay_mod,
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&waitblockheight_pay_mod,
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&retry_pay_mod,
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NULL,
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};
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static struct command_result *json_keysend(struct command *cmd, const char *buf,
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const jsmntok_t *params)
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{
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struct payment *p;
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const char *label;
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struct amount_msat *exemptfee, *msat;
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struct node_id *destination;
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u64 *maxfee_pct_millionths;
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u32 *maxdelay;
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unsigned int *retryfor;
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#if DEVELOPER
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bool *use_shadow;
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#endif
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p = payment_new(NULL, cmd, NULL /* No parent */, pay_mods);
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if (!param(cmd, buf, params,
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p_req("destination", param_node_id, &destination),
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p_req("msatoshi", param_msat, &msat),
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p_opt("label", param_string, &label),
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p_opt_def("maxfeepercent", param_millionths,
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&maxfee_pct_millionths, 500000),
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p_opt_def("retry_for", param_number, &retryfor, 60),
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p_opt_def("maxdelay", param_number, &maxdelay,
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maxdelay_default),
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p_opt_def("exemptfee", param_msat, &exemptfee, AMOUNT_MSAT(5000)),
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#if DEVELOPER
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p_opt_def("use_shadow", param_bool, &use_shadow, true),
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#endif
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NULL))
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return command_param_failed();
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p->local_id = &my_id;
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p->json_buffer = tal_steal(p, buf);
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p->json_toks = params;
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p->destination = tal_steal(p, destination);
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p->payment_secret = NULL;
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p->amount = *msat;
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p->invoice = NULL;
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p->bolt11 = NULL;
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p->why = "Initial attempt";
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p->constraints.cltv_budget = *maxdelay;
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p->deadline = timeabs_add(time_now(), time_from_sec(*retryfor));
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p->getroute->riskfactorppm = 10000000;
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if (!amount_msat_fee(&p->constraints.fee_budget, p->amount, 0,
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*maxfee_pct_millionths / 100)) {
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tal_free(p);
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return command_fail(
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cmd, JSONRPC2_INVALID_PARAMS,
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"Overflow when computing fee budget, fee rate too high.");
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}
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p->constraints.cltv_budget = *maxdelay;
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payment_mod_exemptfee_get_data(p)->amount = *exemptfee;
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#if DEVELOPER
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payment_mod_shadowroute_get_data(p)->use_shadow = *use_shadow;
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#endif
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p->label = tal_steal(p, label);
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payment_start(p);
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return command_still_pending(cmd);
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}
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static const struct plugin_command commands[] = {
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{
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"keysend",
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"payment",
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"Send a payment without an invoice to a node",
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"Send an unsolicited payment of {amount} to {destination}, by providing the recipient the necessary information to claim the payment",
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json_keysend
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},
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};
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static struct command_result *
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