#include #include #include #include #include #include #include #define DEFAULT_FINAL_CLTV_DELTA 9 struct payment *payment_new(tal_t *ctx, struct command *cmd, struct payment *parent, struct payment_modifier **mods) { struct payment *p = tal(ctx, struct payment); p->children = tal_arr(p, struct payment *, 0); p->parent = parent; p->modifiers = mods; p->cmd = cmd; p->start_time = time_now(); p->result = NULL; p->why = NULL; p->getroute = tal(p, struct getroute_request); p->label = NULL; p->failreason = NULL; p->getroute->riskfactorppm = 10000000; p->abort = false; /* Copy over the relevant pieces of information. */ if (parent != NULL) { assert(cmd == NULL); tal_arr_expand(&parent->children, p); p->destination = parent->destination; p->amount = parent->amount; p->payment_hash = parent->payment_hash; p->partid = payment_root(p->parent)->next_partid++; p->plugin = parent->plugin; /* Re-establish the unmodified constraints for our sub-payment. */ p->constraints = *parent->start_constraints; p->deadline = parent->deadline; p->invoice = parent->invoice; } else { assert(cmd != NULL); p->partid = 0; p->next_partid = 1; p->plugin = cmd->plugin; p->channel_hints = tal_arr(p, struct channel_hint, 0); p->excluded_nodes = tal_arr(p, struct node_id, 0); } /* Initialize all modifier data so we can point to the fields when * wiring into the param() call in a JSON-RPC handler. The callback * can also just `memcpy` the parent if this outside access is not * required. */ p->modifier_data = tal_arr(p, void *, 0); for (size_t i=0; mods[i] != NULL; i++) { if (mods[i]->data_init != NULL) tal_arr_expand(&p->modifier_data, mods[i]->data_init(p)); else tal_arr_expand(&p->modifier_data, NULL); } return p; } struct payment *payment_root(struct payment *p) { if (p->parent == NULL) return p; else return payment_root(p->parent); } /* Generic handler for RPC failures that should end up failing the payment. */ static struct command_result *payment_rpc_failure(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { payment_fail(p, "Failing a partial payment due to a failed RPC call: %.*s", toks->end - toks->start, buffer + toks->start); return command_still_pending(cmd); } struct payment_tree_result payment_collect_result(struct payment *p) { struct payment_tree_result res; size_t numchildren = tal_count(p->children); res.sent = AMOUNT_MSAT(0); res.attempts = 1; res.treestates = p->step; res.leafstates = 0; res.preimage = NULL; res.failure = NULL; if (p->step == PAYMENT_STEP_FAILED && p->result != NULL) res.failure = p->result; if (numchildren == 0) { res.leafstates |= p->step; if (p->result && p->result->state == PAYMENT_COMPLETE) { res.sent = p->result->amount_sent; res.preimage = p->result->payment_preimage; } } for (size_t i = 0; i < numchildren; i++) { struct payment_tree_result cres = payment_collect_result(p->children[i]); /* Some of our subpayments have succeeded, aggregate how much * we sent in total. */ if (!amount_msat_add(&res.sent, res.sent, cres.sent)) plugin_err( p->plugin, "Number overflow summing partial payments: %s + %s", type_to_string(tmpctx, struct amount_msat, &res.sent), type_to_string(tmpctx, struct amount_msat, &cres.sent)); /* Bubble up the first preimage we see. */ if (res.preimage == NULL && cres.preimage != NULL) res.preimage = cres.preimage; res.leafstates |= cres.leafstates; res.treestates |= cres.treestates; res.attempts += cres.attempts; /* We bubble the failure result with the highest failcode up * to the root. */ if (res.failure == NULL || (cres.failure != NULL && cres.failure->failcode > res.failure->failcode)) { res.failure = cres.failure; } } return res; } static struct command_result *payment_getinfo_success(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { const jsmntok_t *blockheighttok = json_get_member(buffer, toks, "blockheight"); json_to_number(buffer, blockheighttok, &p->start_block); payment_continue(p); return command_still_pending(cmd); } void payment_start(struct payment *p) { struct payment *root = payment_root(p); p->step = PAYMENT_STEP_INITIALIZED; p->current_modifier = -1; /* Pre-generate the getroute request, so modifiers can have their say, * before we actually call `getroute` */ p->getroute->destination = p->destination; p->getroute->max_hops = ROUTING_MAX_HOPS; if (root->invoice != NULL && root->invoice->min_final_cltv_expiry != 0) p->getroute->cltv = root->invoice->min_final_cltv_expiry; else p->getroute->cltv = DEFAULT_FINAL_CLTV_DELTA; p->getroute->amount = p->amount; p->start_constraints = tal_dup(p, struct payment_constraints, &p->constraints); /* TODO If this is not the root, we can actually skip the getinfo call * and just reuse the parent's value. */ send_outreq(p->plugin, jsonrpc_request_start(p->plugin, NULL, "getinfo", payment_getinfo_success, payment_rpc_failure, p)); } static void payment_exclude_most_expensive(struct payment *p) { struct payment *root = payment_root(p); struct route_hop *e = &p->route[0]; struct amount_msat fee, worst = AMOUNT_MSAT(0); struct channel_hint hint; for (size_t i = 0; i < tal_count(p->route)-1; i++) { if (!amount_msat_sub(&fee, p->route[i].amount, p->route[i+1].amount)) plugin_err(p->plugin, "Negative fee in a route."); if (amount_msat_greater_eq(fee, worst)) { e = &p->route[i]; worst = fee; } } hint.scid.scid = e->channel_id; hint.scid.dir = e->direction; hint.enabled = false; hint.local = false; tal_arr_expand(&root->channel_hints, hint); } static void payment_exclude_longest_delay(struct payment *p) { struct payment *root = payment_root(p); struct route_hop *e = &p->route[0]; u32 delay, worst = 0; struct channel_hint hint; for (size_t i = 0; i < tal_count(p->route)-1; i++) { delay = p->route[i].delay - p->route[i+1].delay; if (delay >= worst) { e = &p->route[i]; worst = delay; } } hint.scid.scid = e->channel_id; hint.scid.dir = e->direction; hint.enabled = false; hint.local = false; tal_arr_expand(&root->channel_hints, hint); } static struct amount_msat payment_route_fee(struct payment *p) { struct amount_msat fee; if (!amount_msat_sub(&fee, p->route[0].amount, p->amount)) { plugin_log( p->plugin, LOG_BROKEN, "gossipd returned a route with a negative fee: sending %s " "to deliver %s", type_to_string(tmpctx, struct amount_msat, &p->route[0].amount), type_to_string(tmpctx, struct amount_msat, &p->amount)); abort(); } return fee; } /* Update the constraints by subtracting the delta_fee and delta_cltv if the * result is positive. Returns whether or not the update has been applied. */ static WARN_UNUSED_RESULT bool payment_constraints_update(struct payment_constraints *cons, const struct amount_msat delta_fee, const u32 delta_cltv) { if (delta_cltv > cons->cltv_budget) return false; /* amount_msat_sub performs a check before actually subtracting. */ if (!amount_msat_sub(&cons->fee_budget, cons->fee_budget, delta_fee)) return false; cons->cltv_budget -= delta_cltv; return true; } /* Given a route and a couple of channel hints, apply the route to the channel * hints, so we have a better estimation of channel's capacity. We apply a * route to a channel hint before calling `sendonion` so subsequent `route` * calls don't accidentally try to use those out-of-date estimates. We unapply * if the payment failed, i.e., all HTLCs we might have added have been torn * down again. Finally we leave the update in place if the payment went * through, since the balances really changed in that case. The `remove` * argument indicates whether we want to apply (`remove=false`), or clear a * prior application (`remove=true`). */ static void payment_chanhints_apply_route(struct payment *p, bool remove) { struct route_hop *curhop; struct channel_hint *curhint; struct payment *root = payment_root(p); assert(p->route != NULL); for (size_t i = 0; i < tal_count(p->route); i++) { curhop = &p->route[i]; for (size_t j = 0; j < tal_count(root->channel_hints); j++) { curhint = &root->channel_hints[j]; if (short_channel_id_eq(&curhint->scid.scid, &curhop->channel_id) && curhint->scid.dir == curhop->direction) { /* Update the number of htlcs for any local * channel in the route */ if (curhint->local && remove) curhint->htlc_budget++; else if (curhint->local) curhint->htlc_budget--; if (remove && !amount_msat_add( &curhint->estimated_capacity, curhint->estimated_capacity, curhop->amount)) { /* This should never happen, it'd mean * that we unapply a route that would * result in a msatoshi * wrap-around. */ abort(); } else if (!amount_msat_sub( &curhint->estimated_capacity, curhint->estimated_capacity, curhop->amount)) { /* This can happen in case of multipl * concurrent getroute calls using the * same channel_hints, no biggy, it's * an estimation anyway. */ plugin_log( p->plugin, LOG_UNUSUAL, "Could not update the channel hint " "for %s. Could be a concurrent " "`getroute` call.", type_to_string( tmpctx, struct short_channel_id_dir, &curhint->scid)); } } } } } static struct command_result *payment_getroute_result(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { const jsmntok_t *rtok = json_get_member(buffer, toks, "route"); struct amount_msat fee; assert(rtok != NULL); p->route = json_to_route(p, buffer, rtok); p->step = PAYMENT_STEP_GOT_ROUTE; fee = payment_route_fee(p); /* Ensure that our fee and CLTV budgets are respected. */ if (amount_msat_greater(fee, p->constraints.fee_budget)) { payment_exclude_most_expensive(p); payment_fail( p, "Fee exceeds our fee budget: %s > %s, discarding route", type_to_string(tmpctx, struct amount_msat, &fee), type_to_string(tmpctx, struct amount_msat, &p->constraints.fee_budget)); return command_still_pending(cmd); } if (p->route[0].delay > p->constraints.cltv_budget) { payment_exclude_longest_delay(p); payment_fail(p, "CLTV delay exceeds our CLTV budget: %d > %d", p->route[0].delay, p->constraints.cltv_budget); return command_still_pending(cmd); } /* Now update the constraints in fee_budget and cltv_budget so * modifiers know what constraints they need to adhere to. */ if (!payment_constraints_update(&p->constraints, fee, p->route[0].delay)) { plugin_log(p->plugin, LOG_BROKEN, "Could not update constraints."); abort(); } /* Allow modifiers to modify the route, before * payment_compute_onion_payloads uses the route to generate the * onion_payloads */ payment_continue(p); return command_still_pending(cmd); } static struct command_result *payment_getroute_error(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { int code; const jsmntok_t *codetok = json_get_member(buffer, toks, "code"), *msgtok = json_get_member(buffer, toks, "message"); json_to_int(buffer, codetok, &code); p->route = NULL; payment_fail( p, "Error computing a route to %s: %.*s (%d)", type_to_string(tmpctx, struct node_id, p->getroute->destination), json_tok_full_len(msgtok), json_tok_full(buffer, msgtok), code); /* Let payment_finished_ handle this, so we mark it as pending */ return command_still_pending(cmd); } static const struct short_channel_id_dir * payment_get_excluded_channels(const tal_t *ctx, struct payment *p) { struct payment *root = payment_root(p); struct channel_hint *hint; struct short_channel_id_dir *res = tal_arr(ctx, struct short_channel_id_dir, 0); for (size_t i = 0; i < tal_count(root->channel_hints); i++) { hint = &root->channel_hints[i]; if (!hint->enabled) tal_arr_expand(&res, hint->scid); else if (amount_msat_greater_eq(p->amount, hint->estimated_capacity)) tal_arr_expand(&res, hint->scid); else if (hint->local && hint->htlc_budget == 0) /* If we cannot add any HTLCs to the channel we * shouldn't look for a route through that channel */ tal_arr_expand(&res, hint->scid); } return res; } static const struct node_id *payment_get_excluded_nodes(const tal_t *ctx, struct payment *p) { struct payment *root = payment_root(p); return root->excluded_nodes; } /* Iterate through the channel_hints and exclude any channel that we are * confident will not be able to handle this payment. */ static void payment_getroute_add_excludes(struct payment *p, struct json_stream *js) { const struct node_id *nodes; const struct short_channel_id_dir *chans; json_array_start(js, "exclude"); /* Collect and exclude all channels that are disabled or we know have * insufficient capacity. */ chans = payment_get_excluded_channels(tmpctx, p); for (size_t i=0; iplugin, NULL, "getroute", payment_getroute_result, payment_getroute_error, p); json_add_node_id(req->js, "id", p->getroute->destination); json_add_amount_msat_only(req->js, "msatoshi", p->getroute->amount); json_add_num(req->js, "cltv", p->getroute->cltv); json_add_num(req->js, "maxhops", p->getroute->max_hops); json_add_member(req->js, "riskfactor", false, "%lf", p->getroute->riskfactorppm / 1000000.0); payment_getroute_add_excludes(p, req->js); send_outreq(p->plugin, req); } static u8 *tal_towire_legacy_payload(const tal_t *ctx, const struct legacy_payload *payload) { const u8 padding[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; /* Prepend 0 byte for realm */ u8 *buf = tal_arrz(ctx, u8, 1); towire_short_channel_id(&buf, &payload->scid); towire_u64(&buf, payload->forward_amt.millisatoshis); /* Raw: low-level serializer */ towire_u32(&buf, payload->outgoing_cltv); towire(&buf, padding, ARRAY_SIZE(padding)); assert(tal_bytelen(buf) == 1 + 32); return buf; } static struct payment_result *tal_sendpay_result_from_json(const tal_t *ctx, const char *buffer, const jsmntok_t *toks) { const jsmntok_t *idtok = json_get_member(buffer, toks, "id"); const jsmntok_t *hashtok = json_get_member(buffer, toks, "payment_hash"); const jsmntok_t *partidtok = json_get_member(buffer, toks, "partid"); const jsmntok_t *senttok = json_get_member(buffer, toks, "amount_sent_msat"); const jsmntok_t *statustok = json_get_member(buffer, toks, "status"); const jsmntok_t *preimagetok = json_get_member(buffer, toks, "payment_preimage"); const jsmntok_t *codetok = json_get_member(buffer, toks, "code"); const jsmntok_t *datatok = json_get_member(buffer, toks, "data"); const jsmntok_t *erridxtok, *msgtok, *failcodetok, *rawmsgtok, *failcodenametok, *errchantok, *errnodetok, *errdirtok; struct payment_result *result; /* Check if we have an error and need to descend into data to get * details. */ if (codetok != NULL && datatok != NULL) { idtok = json_get_member(buffer, datatok, "id"); hashtok = json_get_member(buffer, datatok, "payment_hash"); partidtok = json_get_member(buffer, datatok, "partid"); senttok = json_get_member(buffer, datatok, "amount_sent_msat"); statustok = json_get_member(buffer, datatok, "status"); } /* Initial sanity checks, all these fields must exist. */ if (idtok == NULL || idtok->type != JSMN_PRIMITIVE || hashtok == NULL || hashtok->type != JSMN_STRING || senttok == NULL || senttok->type != JSMN_STRING || statustok == NULL || statustok->type != JSMN_STRING) { return NULL; } result = tal(ctx, struct payment_result); if (codetok != NULL) json_to_u32(buffer, codetok, &result->code); else result->code = 0; /* If the partid is 0 it'd be omitted in waitsendpay, fix this here. */ if (partidtok != NULL) json_to_u32(buffer, partidtok, &result->partid); else result->partid = 0; json_to_u64(buffer, idtok, &result->id); json_to_msat(buffer, senttok, &result->amount_sent); if (json_tok_streq(buffer, statustok, "pending")) { result->state = PAYMENT_PENDING; } else if (json_tok_streq(buffer, statustok, "complete")) { result->state = PAYMENT_COMPLETE; } else if (json_tok_streq(buffer, statustok, "failed")) { result->state = PAYMENT_FAILED; } else { goto fail; } if (preimagetok != NULL) { result->payment_preimage = tal(result, struct preimage); json_to_preimage(buffer, preimagetok, result->payment_preimage); } /* Now extract the error details if the error code is not 0 */ if (result->code != 0) { erridxtok = json_get_member(buffer, datatok, "erring_index"); errnodetok = json_get_member(buffer, datatok, "erring_node"); errchantok = json_get_member(buffer, datatok, "erring_channel"); errdirtok = json_get_member(buffer, datatok, "erring_direction"); failcodetok = json_get_member(buffer, datatok, "failcode"); failcodenametok =json_get_member(buffer, datatok, "failcodename"); msgtok = json_get_member(buffer, toks, "message"); rawmsgtok = json_get_member(buffer, datatok, "raw_message"); if (failcodetok == NULL || failcodetok->type != JSMN_PRIMITIVE || (failcodenametok != NULL && failcodenametok->type != JSMN_STRING) || (erridxtok != NULL && erridxtok->type != JSMN_PRIMITIVE) || (errnodetok != NULL && errnodetok->type != JSMN_STRING) || (errchantok != NULL && errchantok->type != JSMN_STRING) || (errdirtok != NULL && errdirtok->type != JSMN_PRIMITIVE) || msgtok == NULL || msgtok->type != JSMN_STRING || (rawmsgtok != NULL && rawmsgtok->type != JSMN_STRING)) goto fail; if (rawmsgtok != NULL) result->raw_message = json_tok_bin_from_hex(result, buffer, rawmsgtok); else result->raw_message = NULL; if (failcodenametok != NULL) result->failcodename = json_strdup(result, buffer, failcodenametok); else result->failcodename = NULL; json_to_u32(buffer, failcodetok, &result->failcode); result->message = json_strdup(result, buffer, msgtok); if (erridxtok != NULL) { result->erring_index = tal(result, u32); json_to_u32(buffer, erridxtok, result->erring_index); } else { result->erring_index = NULL; } if (errdirtok != NULL) { result->erring_direction = tal(result, int); json_to_int(buffer, errdirtok, result->erring_direction); } else { result->erring_direction = NULL; } if (errnodetok != NULL) { result->erring_node = tal(result, struct node_id); json_to_node_id(buffer, errnodetok, result->erring_node); } else { result->erring_node = NULL; } if (errchantok != NULL) { result->erring_channel = tal(result, struct short_channel_id); json_to_short_channel_id(buffer, errchantok, result->erring_channel); } else { result->erring_channel = NULL; } } return result; fail: return tal_free(result); } static void channel_hints_update(struct payment *root, const struct short_channel_id *scid, int direction, bool enabled, struct amount_msat estimated_capacity) { struct channel_hint hint; /* Try and look for an existing hint: */ for (size_t i=0; ichannel_hints); i++) { struct channel_hint *hint = &root->channel_hints[i]; if (short_channel_id_eq(&hint->scid.scid, scid) && hint->scid.dir == direction) { /* Prefer to disable a channel. */ hint->enabled = hint->enabled & enabled; /* Prefer the more conservative estimate. */ if (amount_msat_greater(hint->estimated_capacity, estimated_capacity)) hint->estimated_capacity = estimated_capacity; return; } } /* No hint found, create one. */ hint.enabled = enabled; hint.scid.scid = *scid; hint.scid.dir = direction; hint.estimated_capacity = estimated_capacity; hint.local = false; tal_arr_expand(&root->channel_hints, hint); plugin_log( root->plugin, LOG_DBG, "Added a channel hint for %s: enabled %s, estimated capacity %s", type_to_string(tmpctx, struct short_channel_id_dir, &hint.scid), hint.enabled ? "true" : "false", type_to_string(tmpctx, struct amount_msat, &hint.estimated_capacity)); } /* Try to infer the erring_node, erring_channel and erring_direction from what * we know, but don't override the values that are returned by `waitsendpay`. */ static void payment_result_infer(struct route_hop *route, struct payment_result *r) { int i, len; assert(r != NULL); if (r->code == 0 || r->erring_index == NULL || route == NULL) return; len = tal_count(route); i = *r->erring_index; assert(i <= len); if (r->erring_node == NULL) r->erring_node = &route[i-1].nodeid; /* The above assert was enough for the erring_node, but might be off * by one on channel and direction, in case the destination failed on * us. */ if (i == len) return; if (r->erring_channel == NULL) r->erring_channel = &route[i].channel_id; if (r->erring_direction == NULL) r->erring_direction = &route[i].direction; } /* If a node takes too much fee or cltv, the next one reports it. We don't * know who to believe, but log it */ static void report_tampering(struct payment *p, size_t report_pos, const char *style) { const struct node_id *id = &p->route[report_pos].nodeid; if (report_pos == 0) { plugin_log(p->plugin, LOG_UNUSUAL, "Node #%zu (%s) claimed we sent them invalid %s", report_pos + 1, type_to_string(tmpctx, struct node_id, id), style); } else { plugin_log(p->plugin, LOG_UNUSUAL, "Node #%zu (%s) claimed #%zu (%s) sent them invalid %s", report_pos + 1, type_to_string(tmpctx, struct node_id, id), report_pos, type_to_string(tmpctx, struct node_id, &p->route[report_pos-1].nodeid), style); } } static struct command_result * handle_final_failure(struct command *cmd, struct payment *p, const struct node_id *final_id, enum onion_type failcode) { /* We use an exhaustive switch statement here so you get a compile * warning when new ones are added, and can think about where they go */ switch (failcode) { case WIRE_FINAL_INCORRECT_CLTV_EXPIRY: report_tampering(p, tal_count(p->route)-1, "cltv"); goto error; case WIRE_FINAL_INCORRECT_HTLC_AMOUNT: report_tampering(p, tal_count(p->route)-1, "amount"); goto error; /* BOLT #4: * * A _forwarding node_ MAY, but a _final node_ MUST NOT: *... * - return an `invalid_onion_version` error. *... * - return an `invalid_onion_hmac` error. *... * - return an `invalid_onion_key` error. *... * - return a `temporary_channel_failure` error. *... * - return a `permanent_channel_failure` error. *... * - return a `required_channel_feature_missing` error. *... * - return an `unknown_next_peer` error. *... * - return an `amount_below_minimum` error. *... * - return a `fee_insufficient` error. *... * - return an `incorrect_cltv_expiry` error. *... * - return an `expiry_too_soon` error. *... * - return an `expiry_too_far` error. *... * - return a `channel_disabled` error. */ case WIRE_INVALID_ONION_VERSION: case WIRE_INVALID_ONION_HMAC: case WIRE_INVALID_ONION_KEY: case WIRE_TEMPORARY_CHANNEL_FAILURE: case WIRE_PERMANENT_CHANNEL_FAILURE: case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING: case WIRE_UNKNOWN_NEXT_PEER: case WIRE_AMOUNT_BELOW_MINIMUM: case WIRE_FEE_INSUFFICIENT: case WIRE_INCORRECT_CLTV_EXPIRY: case WIRE_EXPIRY_TOO_FAR: case WIRE_EXPIRY_TOO_SOON: case WIRE_CHANNEL_DISABLED: goto strange_error; case WIRE_INVALID_ONION_PAYLOAD: case WIRE_INVALID_REALM: case WIRE_PERMANENT_NODE_FAILURE: case WIRE_TEMPORARY_NODE_FAILURE: case WIRE_REQUIRED_NODE_FEATURE_MISSING: #if EXPERIMENTAL_FEATURES case WIRE_INVALID_ONION_BLINDING: #endif case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS: case WIRE_MPP_TIMEOUT: goto error; } strange_error: plugin_log(p->plugin, LOG_UNUSUAL, "Final node %s reported strange error code %u", type_to_string(tmpctx, struct node_id, final_id), failcode); error: p->result->code = PAY_DESTINATION_PERM_FAIL; payment_root(p)->abort = true; payment_fail(p, "%s", p->result->message); return command_still_pending(cmd); } static struct command_result * handle_intermediate_failure(struct command *cmd, struct payment *p, const struct node_id *errnode, const struct route_hop *errchan, enum onion_type failcode) { struct payment *root = payment_root(p); /* We use an exhaustive switch statement here so you get a compile * warning when new ones are added, and can think about where they go */ switch (failcode) { /* BOLT #4: * * An _intermediate hop_ MUST NOT, but the _final node_: *... * - MUST return an `incorrect_or_unknown_payment_details` error. *... * - MUST return `final_incorrect_cltv_expiry` error. *... * - MUST return a `final_incorrect_htlc_amount` error. */ case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS: case WIRE_FINAL_INCORRECT_CLTV_EXPIRY: case WIRE_FINAL_INCORRECT_HTLC_AMOUNT: /* FIXME: Document in BOLT that intermediates must not return this! */ case WIRE_MPP_TIMEOUT: goto strange_error; case WIRE_PERMANENT_CHANNEL_FAILURE: case WIRE_CHANNEL_DISABLED: case WIRE_UNKNOWN_NEXT_PEER: case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING: /* All of these result in the channel being marked as disabled. */ channel_hints_update(root, &errchan->channel_id, errchan->direction, false, AMOUNT_MSAT(0)); break; case WIRE_TEMPORARY_CHANNEL_FAILURE: { /* These are an indication that the capacity was insufficient, * remember the amount we tried as an estimate. */ struct amount_msat est = errchan->amount; est.millisatoshis *= 0.75; /* Raw: Multiplication */ channel_hints_update(root, &errchan->channel_id, errchan->direction, true, est); goto error; } case WIRE_INCORRECT_CLTV_EXPIRY: report_tampering(p, errchan - p->route, "cltv"); goto error; case WIRE_INVALID_ONION_VERSION: case WIRE_INVALID_ONION_HMAC: case WIRE_INVALID_ONION_KEY: case WIRE_PERMANENT_NODE_FAILURE: case WIRE_TEMPORARY_NODE_FAILURE: case WIRE_REQUIRED_NODE_FEATURE_MISSING: case WIRE_INVALID_ONION_PAYLOAD: case WIRE_INVALID_REALM: #if EXPERIMENTAL_FEATURES case WIRE_INVALID_ONION_BLINDING: #endif tal_arr_expand(&root->excluded_nodes, *errnode); goto error; case WIRE_AMOUNT_BELOW_MINIMUM: case WIRE_FEE_INSUFFICIENT: case WIRE_EXPIRY_TOO_FAR: case WIRE_EXPIRY_TOO_SOON: goto error; } strange_error: plugin_log(p->plugin, LOG_UNUSUAL, "Intermediate node %s reported strange error code %u", type_to_string(tmpctx, struct node_id, errnode), failcode); error: payment_fail(p, "%s", p->result->message); return command_still_pending(cmd); } /* From the docs: * * - *erring_index*: The index of the node along the route that * reported the error. 0 for the local node, 1 for the first hop, * and so on. * * The only difficulty is mapping the erring_index to the correct hop. * We split into the erring node, and the error channel, since they're * used in different contexts. NULL error_channel means it's the final * node, whose errors are treated differently. */ static bool assign_blame(const struct payment *p, const struct node_id **errnode, const struct route_hop **errchan) { int index; if (p->result->erring_index == NULL) return false; index = *p->result->erring_index; /* BADONION errors are reported on behalf of the next node. */ if (p->result->failcode & BADONION) index++; /* Final node *shouldn't* report BADONION, but don't assume. */ if (index >= tal_count(p->route)) { *errchan = NULL; *errnode = &p->route[tal_count(p->route) - 1].nodeid; return true; } *errchan = &p->route[index]; if (index == 0) *errnode = p->local_id; else *errnode = &p->route[index - 1].nodeid; return true; } static struct command_result * payment_waitsendpay_finished(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { const struct node_id *errnode; const struct route_hop *errchan; assert(p->route != NULL); p->end_time = time_now(); p->result = tal_sendpay_result_from_json(p, buffer, toks); if (p->result == NULL) { plugin_log(p->plugin, LOG_UNUSUAL, "Unable to parse `waitsendpay` result: %.*s", json_tok_full_len(toks), json_tok_full(buffer, toks)); payment_set_step(p, PAYMENT_STEP_FAILED); payment_continue(p); return command_still_pending(cmd); } payment_result_infer(p->route, p->result); if (p->result->state == PAYMENT_COMPLETE) { payment_set_step(p, PAYMENT_STEP_SUCCESS); payment_continue(p); return command_still_pending(cmd); } payment_chanhints_apply_route(p, true); if (!assign_blame(p, &errnode, &errchan)) { plugin_log(p->plugin, LOG_UNUSUAL, "No erring_index set in `waitsendpay` result: %.*s", json_tok_full_len(toks), json_tok_full(buffer, toks)); /* FIXME: Pick a random channel to fail? */ payment_set_step(p, PAYMENT_STEP_FAILED); payment_continue(p); return command_still_pending(cmd); } if (!errchan) return handle_final_failure(cmd, p, errnode, p->result->failcode); return handle_intermediate_failure(cmd, p, errnode, errchan, p->result->failcode); } static struct command_result *payment_sendonion_success(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { struct out_req *req; req = jsonrpc_request_start(p->plugin, NULL, "waitsendpay", payment_waitsendpay_finished, payment_waitsendpay_finished, p); json_add_sha256(req->js, "payment_hash", p->payment_hash); json_add_num(req->js, "partid", p->partid); send_outreq(p->plugin, req); return command_still_pending(cmd); } static struct command_result *payment_createonion_success(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { struct out_req *req; struct route_hop *first = &p->route[0]; struct secret *secrets; payment_chanhints_apply_route(p, false); p->createonion_response = json_to_createonion_response(p, buffer, toks); req = jsonrpc_request_start(p->plugin, NULL, "sendonion", payment_sendonion_success, payment_rpc_failure, p); json_add_hex_talarr(req->js, "onion", p->createonion_response->onion); json_object_start(req->js, "first_hop"); json_add_short_channel_id(req->js, "channel", &first->channel_id); json_add_num(req->js, "direction", first->direction); json_add_amount_msat_only(req->js, "amount_msat", first->amount); json_add_num(req->js, "delay", first->delay); json_add_node_id(req->js, "id", &first->nodeid); json_object_end(req->js); json_add_sha256(req->js, "payment_hash", p->payment_hash); json_array_start(req->js, "shared_secrets"); secrets = p->createonion_response->shared_secrets; for(size_t i=0; ijs, NULL, &secrets[i]); json_array_end(req->js); json_add_num(req->js, "partid", p->partid); if (p->label) json_add_string(req->js, "label", p->label); send_outreq(p->plugin, req); return command_still_pending(cmd); } /* Temporary serialization method for the tlv_payload.data until we rework the * API that is generated from the specs to use the setter/getter interface. */ static void tlvstream_set_tlv_payload_data(struct tlv_field **stream, struct secret *payment_secret, u64 total_msat) { u8 *ser = tal_arr(NULL, u8, 0); towire_secret(&ser, payment_secret); towire_tu64(&ser, total_msat); tlvstream_set_raw(stream, TLV_TLV_PAYLOAD_PAYMENT_DATA, ser, tal_bytelen(ser)); tal_free(ser); } static void payment_add_hop_onion_payload(struct payment *p, struct createonion_hop *dst, struct route_hop *node, struct route_hop *next, bool final, struct secret *payment_secret) { struct createonion_request *cr = p->createonion_request; u32 cltv = p->start_block + next->delay; u64 msat = next->amount.millisatoshis; /* Raw: TLV payload generation*/ struct tlv_field **fields; static struct short_channel_id all_zero_scid = {.u64 = 0}; /* This is the information of the node processing this payload, while * `next` are the instructions to include in the payload, which is * basically the channel going to the next node. */ dst->style = node->style; dst->pubkey = node->nodeid; switch (node->style) { case ROUTE_HOP_LEGACY: dst->legacy_payload = tal(cr->hops, struct legacy_payload); dst->legacy_payload->forward_amt = next->amount; if (!final) dst->legacy_payload->scid = next->channel_id; else dst->legacy_payload->scid = all_zero_scid; dst->legacy_payload->outgoing_cltv = cltv; break; case ROUTE_HOP_TLV: dst->tlv_payload = tlv_tlv_payload_new(cr->hops); fields = &dst->tlv_payload->fields; tlvstream_set_tu64(fields, TLV_TLV_PAYLOAD_AMT_TO_FORWARD, msat); tlvstream_set_tu32(fields, TLV_TLV_PAYLOAD_OUTGOING_CLTV_VALUE, cltv); if (!final) tlvstream_set_short_channel_id(fields, TLV_TLV_PAYLOAD_SHORT_CHANNEL_ID, &next->channel_id); if (payment_secret != NULL) { assert(final); tlvstream_set_tlv_payload_data(fields, payment_secret, msat); } break; } } static void payment_compute_onion_payloads(struct payment *p) { struct createonion_request *cr; size_t hopcount; struct payment *root = payment_root(p); p->step = PAYMENT_STEP_ONION_PAYLOAD; hopcount = tal_count(p->route); /* Now compute the payload we're about to pass to `createonion` */ cr = p->createonion_request = tal(p, struct createonion_request); cr->assocdata = tal_arr(cr, u8, 0); towire_sha256(&cr->assocdata, p->payment_hash); cr->session_key = NULL; cr->hops = tal_arr(cr, struct createonion_hop, tal_count(p->route)); /* Non-final hops */ for (size_t i = 0; i < hopcount - 1; i++) { /* The message is destined for hop i, but contains fields for * i+1 */ payment_add_hop_onion_payload(p, &cr->hops[i], &p->route[i], &p->route[i + 1], false, NULL); } /* Final hop */ payment_add_hop_onion_payload( p, &cr->hops[hopcount - 1], &p->route[hopcount - 1], &p->route[hopcount - 1], true, root->payment_secret); /* Now allow all the modifiers to mess with the payloads, before we * serialize via a call to createonion in the next step. */ payment_continue(p); } static void payment_sendonion(struct payment *p) { struct out_req *req; u8 *payload, *tlv; req = jsonrpc_request_start(p->plugin, NULL, "createonion", payment_createonion_success, payment_rpc_failure, p); json_array_start(req->js, "hops"); for (size_t i = 0; i < tal_count(p->createonion_request->hops); i++) { json_object_start(req->js, NULL); struct createonion_hop *hop = &p->createonion_request->hops[i]; json_add_node_id(req->js, "pubkey", &hop->pubkey); if (hop->style == ROUTE_HOP_LEGACY) { payload = tal_towire_legacy_payload(tmpctx, hop->legacy_payload); json_add_hex_talarr(req->js, "payload", payload); }else { tlv = tal_arr(tmpctx, u8, 0); towire_tlvstream_raw(&tlv, hop->tlv_payload->fields); payload = tal_arr(tmpctx, u8, 0); towire_bigsize(&payload, tal_bytelen(tlv)); towire(&payload, tlv, tal_bytelen(tlv)); json_add_hex_talarr(req->js, "payload", payload); tal_free(tlv); } tal_free(payload); json_object_end(req->js); } json_array_end(req->js); json_add_hex_talarr(req->js, "assocdata", p->createonion_request->assocdata); if (p->createonion_request->session_key) json_add_secret(req->js, "sessionkey", p->createonion_request->session_key); send_outreq(p->plugin, req); } /* Mutual recursion. */ static void payment_finished(struct payment *p); /* A payment is finished if a) it is in a final state, of b) it's in a * child-spawning state and all of its children are in a final state. */ static bool payment_is_finished(const struct payment *p) { if (p->step == PAYMENT_STEP_FAILED || p->step == PAYMENT_STEP_SUCCESS || p->abort) return true; else if (p->step == PAYMENT_STEP_SPLIT || p->step == PAYMENT_STEP_RETRY) { bool running_children = false; for (size_t i = 0; i < tal_count(p->children); i++) running_children |= !payment_is_finished(p->children[i]); return !running_children; } else { return false; } } static enum payment_step payment_aggregate_states(struct payment *p) { enum payment_step agg = p->step; for (size_t i=0; ichildren); i++) agg |= payment_aggregate_states(p->children[i]); return agg; } /* A payment is finished if a) it is in a final state, of b) it's in a * child-spawning state and all of its children are in a final state. */ static bool payment_is_success(struct payment *p) { return (payment_aggregate_states(p) & PAYMENT_STEP_SUCCESS) != 0; } /* Function to bubble up completions to the root, which actually holds on to * the command that initiated the flow. */ static void payment_child_finished(struct payment *p, struct payment *child) { if (!payment_is_finished(p)) return; /* Should we continue bubbling up? */ payment_finished(p); } static void payment_add_attempt(struct json_stream *s, const char *fieldname, struct payment *p, bool recurse) { bool finished = p->step >= PAYMENT_STEP_RETRY, success = p->step == PAYMENT_STEP_SUCCESS; /* A fieldname is only reasonable if we're not recursing. Otherwise the * fieldname would be reused for all attempts. */ assert(!recurse || fieldname == NULL); json_object_start(s, fieldname); if (!finished) json_add_string(s, "status", "pending"); else if (success) json_add_string(s, "status", "success"); else json_add_string(s, "status", "failed"); if (p->failreason != NULL) json_add_string(s, "failreason", p->failreason); json_add_u64(s, "partid", p->partid); json_add_amount_msat_only(s, "amount", p->amount); if (p->parent != NULL) json_add_u64(s, "parent_partid", p->parent->partid); json_object_end(s); for (size_t i=0; ichildren); i++) { payment_add_attempt(s, fieldname, p->children[i], recurse); } } static void payment_json_add_attempts(struct json_stream *s, const char *fieldname, struct payment *p) { assert(p == payment_root(p)); json_array_start(s, fieldname); payment_add_attempt(s, NULL, p, true); json_array_end(s); } /* This function is called whenever a payment ends up in a final state, or all * leafs in the subtree rooted in the payment are all in a final state. It is * called only once, and it is guaranteed to be called in post-order * traversal, i.e., all children are finished before the parent is called. */ static void payment_finished(struct payment *p) { struct payment_tree_result result = payment_collect_result(p); struct json_stream *ret; struct command *cmd = p->cmd; const char *msg; /* Either none of the leaf attempts succeeded yet, or we have a * preimage. */ assert((result.leafstates & PAYMENT_STEP_SUCCESS) == 0 || result.preimage != NULL); if (p->parent == NULL) { /* We are about to reply, unset the pointer to the cmd so we * don't attempt to return a response twice. */ p->cmd = NULL; if (cmd == NULL) { /* This is the tree root, but we already reported * success or failure, so noop. */ return; } else if (payment_is_success(p)) { assert(result.treestates & PAYMENT_STEP_SUCCESS); assert(result.leafstates & PAYMENT_STEP_SUCCESS); assert(result.preimage != NULL); ret = jsonrpc_stream_success(cmd); json_add_node_id(ret, "destination", p->destination); json_add_sha256(ret, "payment_hash", p->payment_hash); json_add_timeabs(ret, "created_at", p->start_time); json_add_num(ret, "parts", result.attempts); json_add_amount_msat_compat(ret, p->amount, "msatoshi", "amount_msat"); json_add_amount_msat_compat(ret, result.sent, "msatoshi_sent", "amount_sent_msat"); if (result.leafstates != PAYMENT_STEP_SUCCESS) json_add_string( ret, "warning_partial_completion", "Some parts of the payment are not yet " "completed, but we have the confirmation " "from the recipient."); json_add_preimage(ret, "payment_preimage", result.preimage); json_add_string(ret, "status", "complete"); if (command_finished(cmd, ret)) {/* Ignore result. */} return; } else if (result.failure == NULL || result.failure->failcode < NODE) { /* This is failing because we have no more routes to try */ msg = tal_fmt(cmd, "Ran out of routes to try after " "%d attempt%s: see `paystatus`", result.attempts, result.attempts == 1 ? "" : "s"); ret = jsonrpc_stream_fail(cmd, PAY_STOPPED_RETRYING, msg); payment_json_add_attempts(ret, "attempts", p); if (command_finished(cmd, ret)) {/* Ignore result. */} return; } else { struct payment_result *failure = result.failure; assert(failure!= NULL); ret = jsonrpc_stream_fail(cmd, failure->code, failure->message); json_add_u64(ret, "id", failure->id); json_add_u32(ret, "failcode", failure->failcode); json_add_string(ret, "failcodename", failure->failcodename); if (p->bolt11) json_add_string(ret, "bolt11", p->bolt11); json_add_hex_talarr(ret, "raw_message", result.failure->raw_message); json_add_num(ret, "created_at", p->start_time.ts.tv_sec); json_add_string(ret, "message", result.failure->message); json_add_node_id(ret, "destination", p->destination); json_add_sha256(ret, "payment_hash", p->payment_hash); if (result.leafstates & PAYMENT_STEP_SUCCESS) { /* If one sub-payment succeeded then we have * proof of payment, and the payment is a * success. */ json_add_string(ret, "status", "complete"); } else if (result.leafstates & ~PAYMENT_FAILED) { /* If there are non-failed leafs we are still trying. */ json_add_string(ret, "status", "pending"); } else { json_add_string(ret, "status", "failed"); } json_add_amount_msat_compat(ret, p->amount, "msatoshi", "amount_msat"); json_add_amount_msat_compat(ret, result.sent, "msatoshi_sent", "amount_sent_msat"); if (failure != NULL) { if (failure->erring_index) json_add_num(ret, "erring_index", *failure->erring_index); if (failure->erring_node) json_add_node_id(ret, "erring_node", failure->erring_node); if (failure->erring_channel) json_add_short_channel_id( ret, "erring_channel", failure->erring_channel); if (failure->erring_direction) json_add_num( ret, "erring_direction", *failure->erring_direction); } if (command_finished(cmd, ret)) {/* Ignore result. */} return; } } else { payment_child_finished(p->parent, p); return; } } void payment_set_step(struct payment *p, enum payment_step newstep) { p->current_modifier = -1; p->step = newstep; /* Any final state needs an end_time */ if (p->step >= PAYMENT_STEP_SPLIT) p->end_time = time_now(); } void payment_continue(struct payment *p) { struct payment_modifier *mod; void *moddata; /* If we are in the middle of calling the modifiers, continue calling * them, otherwise we can continue with the payment state-machine. */ p->current_modifier++; mod = p->modifiers[p->current_modifier]; if (mod != NULL) { /* There is another modifier, so call it. */ moddata = p->modifier_data[p->current_modifier]; return mod->post_step_cb(moddata, p); } else { /* There are no more modifiers, so reset the call chain and * proceed to the next state. */ p->current_modifier = -1; switch (p->step) { case PAYMENT_STEP_INITIALIZED: payment_getroute(p); return; case PAYMENT_STEP_GOT_ROUTE: payment_compute_onion_payloads(p); return; case PAYMENT_STEP_ONION_PAYLOAD: payment_sendonion(p); return; case PAYMENT_STEP_SUCCESS: case PAYMENT_STEP_FAILED: payment_finished(p); return; case PAYMENT_STEP_RETRY: case PAYMENT_STEP_SPLIT: /* Do nothing, we'll get pinged by a child succeeding * or failing. */ return; } } /* We should never get here, it'd mean one of the state machine called * `payment_continue` after the final state. */ abort(); } void payment_fail(struct payment *p, const char *fmt, ...) { va_list ap; p->end_time = time_now(); payment_set_step(p, PAYMENT_STEP_FAILED); va_start(ap, fmt); p->failreason = tal_vfmt(p, fmt, ap); va_end(ap); plugin_log(p->plugin, LOG_INFORM, "%s", p->failreason); payment_continue(p); } void *payment_mod_get_data(const struct payment *p, const struct payment_modifier *mod) { for (size_t i = 0; p->modifiers[i] != NULL; i++) if (p->modifiers[i] == mod) return p->modifier_data[i]; /* If we ever get here it means that we asked for the data for a * non-existent modifier. This is a compile-time/wiring issue, so we * better check that modifiers match the data we ask for. */ abort(); } static struct retry_mod_data *retry_data_init(struct payment *p); static inline void retry_step_cb(struct retry_mod_data *rd, struct payment *p); static struct retry_mod_data * retry_data_init(struct payment *p) { struct retry_mod_data *rdata = tal(p, struct retry_mod_data); struct retry_mod_data *parent_rdata; /* We start the retry counter from scratch for the root payment, or if * the parent was split, meaning this is a new attempt with new * amounts. */ if (p->parent == NULL || p->parent->step == PAYMENT_STEP_SPLIT) { rdata->retries = 10; } else { parent_rdata = payment_mod_retry_get_data(p->parent); rdata->retries = parent_rdata->retries - 1; } return rdata; } /* Determine whether retrying could possibly succeed. Retrying in this case * means that we repeat the entire flow, including computing a new route, new * payload and a new sendonion call. It does not mean we retry the exact same * attempt that just failed. */ static bool payment_can_retry(struct payment *p) { struct payment_result *res = p->result; u32 idx; bool is_final; if (p->result == NULL) return false; idx = res->erring_index != NULL ? *res->erring_index : 0; is_final = (idx == tal_count(p->route)); /* Full matrix of failure code x is_final. Prefer to retry once too * often over eagerly failing. */ switch (res->failcode) { case WIRE_EXPIRY_TOO_FAR: case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS: case WIRE_INVALID_ONION_PAYLOAD: case WIRE_INVALID_ONION_VERSION: case WIRE_INVALID_REALM: case WIRE_MPP_TIMEOUT: case WIRE_PERMANENT_NODE_FAILURE: case WIRE_REQUIRED_NODE_FEATURE_MISSING: case WIRE_TEMPORARY_NODE_FAILURE: case WIRE_UNKNOWN_NEXT_PEER: return !is_final; case WIRE_AMOUNT_BELOW_MINIMUM: case WIRE_CHANNEL_DISABLED: case WIRE_EXPIRY_TOO_SOON: case WIRE_FEE_INSUFFICIENT: case WIRE_FINAL_INCORRECT_CLTV_EXPIRY: case WIRE_FINAL_INCORRECT_HTLC_AMOUNT: case WIRE_INCORRECT_CLTV_EXPIRY: case WIRE_INVALID_ONION_HMAC: case WIRE_INVALID_ONION_KEY: case WIRE_PERMANENT_CHANNEL_FAILURE: case WIRE_REQUIRED_CHANNEL_FEATURE_MISSING: case WIRE_TEMPORARY_CHANNEL_FAILURE: #if EXPERIMENTAL_FEATURES case WIRE_INVALID_ONION_BLINDING: #endif return true; } /* We should never get here, otherwise the above `switch` isn't * exhaustive. Nevertheless the failcode is provided by the erring * node, so retry anyway. `abort()`ing on externally supplied info is * not a good idea. */ return true; } static inline void retry_step_cb(struct retry_mod_data *rd, struct payment *p) { struct payment *subpayment, *root = payment_root(p); struct retry_mod_data *rdata = payment_mod_retry_get_data(p); struct timeabs now = time_now(); if (p->step != PAYMENT_STEP_FAILED) return payment_continue(p); if (time_after(now, p->deadline)) { plugin_log( p->plugin, LOG_INFORM, "Payment deadline expired, not retrying (partial-)payment " "%s/%d", type_to_string(tmpctx, struct sha256, p->payment_hash), p->partid); root->abort = true; return payment_continue(p); } /* If we failed to find a route, it's unlikely we can suddenly find a * new one without any other changes, so it's time to give up. */ if (p->route == NULL) return payment_continue(p); /* If the root is marked as abort, we do not retry anymore */ if (payment_root(p)->abort) return payment_continue(p); if (!payment_can_retry(p)) return payment_continue(p); /* If the failure was not final, and we tried a route, try again. */ if (rdata->retries > 0) { subpayment = payment_new(p, NULL, p, p->modifiers); payment_start(subpayment); payment_set_step(p, PAYMENT_STEP_RETRY); subpayment->why = tal_fmt(subpayment, "Still have %d attempts left", rdata->retries - 1); plugin_log( p->plugin, LOG_DBG, "Retrying %s/%d (%s), new partid %d. %d attempts left\n", type_to_string(tmpctx, struct sha256, p->payment_hash), p->partid, type_to_string(tmpctx, struct amount_msat, &p->amount), subpayment->partid, rdata->retries - 1); } payment_continue(p); } REGISTER_PAYMENT_MODIFIER(retry, struct retry_mod_data *, retry_data_init, retry_step_cb); static struct command_result * local_channel_hints_listpeers(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { const jsmntok_t *peers, *peer, *channels, *channel, *spendsats, *scid, *dir, *connected, *max_htlc, *htlcs; size_t i, j; peers = json_get_member(buffer, toks, "peers"); if (peers == NULL) goto done; /* cppcheck-suppress uninitvar - cppcheck can't undestand these macros. */ json_for_each_arr(i, peer, peers) { channels = json_get_member(buffer, peer, "channels"); if (channels == NULL) continue; connected = json_get_member(buffer, peer, "connected"); json_for_each_arr(j, channel, channels) { struct channel_hint h; spendsats = json_get_member(buffer, channel, "spendable_msat"); scid = json_get_member(buffer, channel, "short_channel_id"); dir = json_get_member(buffer, channel, "direction"); max_htlc = json_get_member(buffer, channel, "max_accepted_htlcs"); htlcs = json_get_member(buffer, channel, "htlcs"); if (spendsats == NULL || scid == NULL || dir == NULL || max_htlc == NULL || max_htlc->type != JSMN_PRIMITIVE || htlcs == NULL || htlcs->type != JSMN_ARRAY) continue; json_to_bool(buffer, connected, &h.enabled); json_to_short_channel_id(buffer, scid, &h.scid.scid); json_to_int(buffer, dir, &h.scid.dir); json_to_msat(buffer, spendsats, &h.estimated_capacity); /* Take the configured number of max_htlcs and * subtract any HTLCs that might already be added to * the channel. This is a best effort estimate and * mostly considers stuck htlcs, concurrent payments * may throw us off a bit. */ json_to_u16(buffer, max_htlc, &h.htlc_budget); h.htlc_budget -= htlcs->size; h.local = true; tal_arr_expand(&p->channel_hints, h); } } done: payment_continue(p); return command_still_pending(cmd); } static void local_channel_hints_cb(void *d UNUSED, struct payment *p) { struct out_req *req; /* If we are not the root we don't look up the channel balances since * it is unlikely that the capacities have changed much since the root * payment looked at them. We also only call `listpeers` when the * payment is in state PAYMENT_STEP_INITIALIZED, right before calling * `getroute`. */ if (p->parent != NULL || p->step != PAYMENT_STEP_INITIALIZED) return payment_continue(p); req = jsonrpc_request_start(p->plugin, NULL, "listpeers", local_channel_hints_listpeers, local_channel_hints_listpeers, p); send_outreq(p->plugin, req); } REGISTER_PAYMENT_MODIFIER(local_channel_hints, void *, NULL, local_channel_hints_cb); /* Trim route to this length by taking from the *front* of route * (end points to destination, so we need that bit!) */ static void trim_route(struct route_info **route, size_t n) { size_t remove = tal_count(*route) - n; memmove(*route, *route + remove, sizeof(**route) * n); tal_resize(route, n); } /* Make sure routehints are reasonable length, and (since we assume we * can append), not directly to us. Note: untrusted data! */ static struct route_info **filter_routehints(struct routehints_data *d, struct node_id *myid, struct route_info **hints) { char *mods = tal_strdup(tmpctx, ""); for (size_t i = 0; i < tal_count(hints); i++) { /* Trim any routehint > 10 hops */ size_t max_hops = ROUTING_MAX_HOPS / 2; if (tal_count(hints[i]) > max_hops) { tal_append_fmt(&mods, "Trimmed routehint %zu (%zu hops) to %zu. ", i, tal_count(hints[i]), max_hops); trim_route(&hints[i], max_hops); } /* If we are first hop, trim. */ if (tal_count(hints[i]) > 0 && node_id_eq(&hints[i][0].pubkey, myid)) { tal_append_fmt(&mods, "Removed ourselves from routehint %zu. ", i); trim_route(&hints[i], tal_count(hints[i])-1); } /* If route is empty, remove altogether. */ if (tal_count(hints[i]) == 0) { tal_append_fmt(&mods, "Removed empty routehint %zu. ", i); tal_arr_remove(&hints, i); i--; } } if (!streq(mods, "")) d->routehint_modifications = tal_steal(d, mods); return tal_steal(d, hints); } static bool routehint_excluded(struct payment *p, const struct route_info *routehint) { const struct node_id *nodes = payment_get_excluded_nodes(tmpctx, p); const struct short_channel_id_dir *chans = payment_get_excluded_channels(tmpctx, p); /* Note that we ignore direction here: in theory, we could have * found that one direction of a channel is unavailable, but they * are suggesting we use it the other way. Very unlikely though! */ for (size_t i = 0; i < tal_count(routehint); i++) { const struct route_info *r = &routehint[i]; for (size_t j=0; tal_count(nodes); j++) if (node_id_eq(&r->pubkey, &nodes[j])) return true; for (size_t j = 0; j < tal_count(chans); j++) if (short_channel_id_eq(&chans[j].scid, &r->short_channel_id)) return true; } return false; } static struct route_info *next_routehint(struct routehints_data *d, struct payment *p) { while (tal_count(d->routehints) > 0) { if (!routehint_excluded(p, d->routehints[0])) { d->current_routehint = d->routehints[0]; tal_arr_remove(&d->routehints, 0); return d->current_routehint; } tal_free(d->routehints[0]); tal_arr_remove(&d->routehints, 0); } return NULL; } /* Calculate how many millisatoshi we need at the start of this route * to get msatoshi to the end. */ static bool route_msatoshi(struct amount_msat *total, const struct amount_msat msat, const struct route_info *route, size_t num_route) { *total = msat; for (ssize_t i = num_route - 1; i >= 0; i--) { if (!amount_msat_add_fee(total, route[i].fee_base_msat, route[i].fee_proportional_millionths)) return false; } return true; } /* The pubkey to use is the destination of this routehint. */ static const struct node_id *route_pubkey(const struct payment *p, const struct route_info *routehint, size_t n) { if (n == tal_count(routehint)) return p->destination; return &routehint[n].pubkey; } static u32 route_cltv(u32 cltv, const struct route_info *route, size_t num_route) { for (size_t i = 0; i < num_route; i++) cltv += route[i].cltv_expiry_delta; return cltv; } static void routehint_step_cb(struct routehints_data *d, struct payment *p) { struct routehints_data *pd; struct route_hop hop; const struct payment *root = payment_root(p); if (p->step == PAYMENT_STEP_INITIALIZED) { if (root->invoice == NULL || root->invoice->routes == NULL) return payment_continue(p); /* The root payment gets the unmodified routehints, children may * start dropping some as they learn that they were not * functional. */ if (p->parent == NULL) { d->routehints = filter_routehints(d, p->local_id, p->invoice->routes); } else { pd = payment_mod_get_data(p->parent, &routehints_pay_mod); d->routehints = tal_dup_talarr(d, struct route_info *, pd->routehints); } d->current_routehint = next_routehint(d, p); if (d->current_routehint != NULL) { /* Change the destination and compute the final msatoshi * amount to send to the routehint entry point. */ if (!route_msatoshi(&p->getroute->amount, p->amount, d->current_routehint, tal_count(d->current_routehint))) { } d->final_cltv = p->getroute->cltv; p->getroute->destination = &d->current_routehint[0].pubkey; p->getroute->cltv = route_cltv(p->getroute->cltv, d->current_routehint, tal_count(d->current_routehint)); } } else if (p->step == PAYMENT_STEP_GOT_ROUTE) { /* Now it's time to stitch the two partial routes together. */ struct amount_msat dest_amount; struct route_info *routehint = d->current_routehint; struct route_hop *prev_hop; for (ssize_t i = 0; i < tal_count(routehint); i++) { prev_hop = &p->route[tal_count(p->route)-1]; if (!route_msatoshi(&dest_amount, p->amount, routehint + i + 1, tal_count(routehint) - i - 1)) { /* Just let it fail, since we couldn't stitch * the routes together. */ return payment_continue(p); } hop.nodeid = *route_pubkey(p, routehint, i + 1); hop.style = ROUTE_HOP_TLV; hop.channel_id = routehint[i].short_channel_id; hop.amount = dest_amount; hop.delay = route_cltv(d->final_cltv, routehint + i + 1, tal_count(routehint) - i - 1); /* Should we get a failure inside the routehint we'll * need the direction so we can exclude it. Luckily * it's rather easy to compute given the two * subsequent hops. */ hop.direction = node_id_cmp(&prev_hop->nodeid, &hop.nodeid) > 0 ? 1 : 0; tal_arr_expand(&p->route, hop); } } payment_continue(p); } static struct routehints_data *routehint_data_init(struct payment *p) { /* We defer the actual initialization to the step callback when we have * the invoice attached. */ return talz(p, struct routehints_data); } REGISTER_PAYMENT_MODIFIER(routehints, struct routehints_data *, routehint_data_init, routehint_step_cb); /* For tiny payments the fees incurred due to the fixed base_fee may dominate * the overall cost of the payment. Since these payments are often used as a * way to signal, rather than actually transfer the amount, we add an * exemption that allows tiny payments to exceed the fee allowance. This is * implemented by setting a larger allowance than we would normally do if the * payment is below the threshold. */ static struct exemptfee_data *exemptfee_data_init(struct payment *p) { if (p->parent == NULL) { struct exemptfee_data *d = tal(p, struct exemptfee_data); d->amount = AMOUNT_MSAT(5000); return d; } else { return payment_mod_exemptfee_get_data(p->parent); } } static void exemptfee_cb(struct exemptfee_data *d, struct payment *p) { if (p->step != PAYMENT_STEP_INITIALIZED || p->parent != NULL) return payment_continue(p); if (amount_msat_greater_eq(d->amount, p->constraints.fee_budget)) { plugin_log( p->plugin, LOG_INFORM, "Payment fee constraint %s is below exemption threshold, " "allowing a maximum fee of %s", type_to_string(tmpctx, struct amount_msat, &p->constraints.fee_budget), type_to_string(tmpctx, struct amount_msat, &d->amount)); p->constraints.fee_budget = d->amount; p->start_constraints->fee_budget = d->amount; } return payment_continue(p); } REGISTER_PAYMENT_MODIFIER(exemptfee, struct exemptfee_data *, exemptfee_data_init, exemptfee_cb); /* BOLT #7: * * If a route is computed by simply routing to the intended recipient and * summing the `cltv_expiry_delta`s, then it's possible for intermediate nodes * to guess their position in the route. Knowing the CLTV of the HTLC, the * surrounding network topology, and the `cltv_expiry_delta`s gives an * attacker a way to guess the intended recipient. Therefore, it's highly * desirable to add a random offset to the CLTV that the intended recipient * will receive, which bumps all CLTVs along the route. * * In order to create a plausible offset, the origin node MAY start a limited * random walk on the graph, starting from the intended recipient and summing * the `cltv_expiry_delta`s, and use the resulting sum as the offset. This * effectively creates a _shadow route extension_ to the actual route and * provides better protection against this attack vector than simply picking a * random offset would. */ static struct shadow_route_data *shadow_route_init(struct payment *p) { struct shadow_route_data *d = tal(p, struct shadow_route_data), *pd; /* If we're not the root we need to inherit the flags set only on the * root payment. Since we inherit them at each step it's sufficient to * do so from our direct parent. */ if (p->parent != NULL) { pd = payment_mod_shadowroute_get_data(p->parent); d->fuzz_amount = pd->fuzz_amount; #if DEVELOPER d->use_shadow = pd->use_shadow; #endif } else { d->fuzz_amount = true; } return d; } /* Mutual recursion */ static struct command_result *shadow_route_listchannels(struct command *cmd, const char *buf, const jsmntok_t *result, struct payment *p); static struct command_result *shadow_route_extend(struct shadow_route_data *d, struct payment *p) { struct out_req *req; req = jsonrpc_request_start(p->plugin, NULL, "listchannels", shadow_route_listchannels, payment_rpc_failure, p); json_add_string(req->js, "source", type_to_string(req, struct node_id, &d->destination)); return send_outreq(p->plugin, req); } static struct command_result *shadow_route_listchannels(struct command *cmd, const char *buf, const jsmntok_t *result, struct payment *p) { /* Use reservoir sampling across the capable channels. */ struct shadow_route_data *d = payment_mod_shadowroute_get_data(p); struct payment_constraints *cons = &d->constraints; struct route_info *best = NULL; size_t i; u64 sample = 0; struct amount_msat best_fee; const jsmntok_t *sattok, *delaytok, *basefeetok, *propfeetok, *desttok, *channelstok, *chan, *scidtok; /* Check the invariants on the constraints between payment and modifier. */ assert(d->constraints.cltv_budget <= p->constraints.cltv_budget / 4); assert(amount_msat_greater_eq(p->constraints.fee_budget, d->constraints.fee_budget)); channelstok = json_get_member(buf, result, "channels"); json_for_each_arr(i, chan, channelstok) { u64 v = pseudorand(UINT64_MAX); struct route_info curr; struct amount_sat capacity; struct amount_msat fee; sattok = json_get_member(buf, chan, "satoshis"); delaytok = json_get_member(buf, chan, "delay"); basefeetok = json_get_member(buf, chan, "base_fee_millisatoshi"); propfeetok = json_get_member(buf, chan, "fee_per_millionth"); scidtok = json_get_member(buf, chan, "short_channel_id"); desttok = json_get_member(buf, chan, "destination"); if (sattok == NULL || delaytok == NULL || delaytok->type != JSMN_PRIMITIVE || basefeetok == NULL || basefeetok->type != JSMN_PRIMITIVE || propfeetok == NULL || propfeetok->type != JSMN_PRIMITIVE || desttok == NULL || scidtok == NULL) continue; json_to_u16(buf, delaytok, &curr.cltv_expiry_delta); json_to_number(buf, basefeetok, &curr.fee_base_msat); json_to_number(buf, propfeetok, &curr.fee_proportional_millionths); json_to_short_channel_id(buf, scidtok, &curr.short_channel_id); json_to_sat(buf, sattok, &capacity); json_to_node_id(buf, desttok, &curr.pubkey); if (!best || v > sample) { /* If the capacity is insufficient to pass the amount * it's not a plausible extension. */ if (amount_msat_greater_sat(p->amount, capacity)) continue; if (curr.cltv_expiry_delta > cons->cltv_budget) continue; if (!amount_msat_fee( &fee, p->amount, curr.fee_base_msat, curr.fee_proportional_millionths)) { /* Fee computation failed... */ continue; } if (amount_msat_greater_eq(fee, cons->fee_budget)) continue; best = tal_dup(tmpctx, struct route_info, &curr); best_fee = fee; sample = v; } } if (best != NULL) { /* Check that we could apply the shadow route extension. Check * against both the shadow route budget as well as the * original payment's budget. */ if (best->cltv_expiry_delta > d->constraints.cltv_budget || best->cltv_expiry_delta > p->constraints.cltv_budget) { best = NULL; goto next; } /* Check the fee budget only if we didn't opt out, since * testing against a virtual budget is not useful if we do not * actually use it (it could give false positives and fail * attempts that might have gone through, */ if (d->fuzz_amount && (amount_msat_greater(best_fee, d->constraints.fee_budget) || (amount_msat_greater(best_fee, p->constraints.fee_budget)))) { best = NULL; goto next; } /* Now we can be sure that adding the shadow route will succeed */ plugin_log( p->plugin, LOG_DBG, "Adding shadow_route hop over channel %s: adding %s " "in fees and %d CLTV delta", type_to_string(tmpctx, struct short_channel_id, &best->short_channel_id), type_to_string(tmpctx, struct amount_msat, &best_fee), best->cltv_expiry_delta); d->destination = best->pubkey; d->constraints.cltv_budget -= best->cltv_expiry_delta; p->getroute->cltv += best->cltv_expiry_delta; if (!d->fuzz_amount) goto next; /* Only try to apply the fee budget changes if we want to fuzz * the amount. Virtual fees that we then don't deliver to the * destination could otherwise cause the route to be too * expensive, while really being ok. If any of these fail then * the above checks are insufficient. */ if (!amount_msat_sub(&d->constraints.fee_budget, d->constraints.fee_budget, best_fee) || !amount_msat_sub(&p->constraints.fee_budget, p->constraints.fee_budget, best_fee)) plugin_err(p->plugin, "Could not update fee constraints " "for shadow route extension. " "payment fee budget %s, modifier " "fee budget %s, shadow fee to add %s", type_to_string(tmpctx, struct amount_msat, &p->constraints.fee_budget), type_to_string(tmpctx, struct amount_msat, &d->constraints.fee_budget), type_to_string(tmpctx, struct amount_msat, &best_fee)); } next: /* Now it's time to decide whether we want to extend or continue. */ if (best == NULL || pseudorand(2) == 0) { payment_continue(p); return command_still_pending(cmd); } else { return shadow_route_extend(d, p); } } static void shadow_route_cb(struct shadow_route_data *d, struct payment *p) { #if DEVELOPER if (!d->use_shadow) return payment_continue(p); #endif if (p->step != PAYMENT_STEP_INITIALIZED) return payment_continue(p); d->destination = *p->destination; /* Allow shadowroutes to consume up to 1/4th of our budget. */ d->constraints.cltv_budget = p->constraints.cltv_budget / 4; d->constraints.fee_budget = p->constraints.fee_budget; d->constraints.fee_budget.millisatoshis /= 4; /* Raw: msat division. */ if (pseudorand(2) == 0) { return payment_continue(p); } else { shadow_route_extend(d, p); } } REGISTER_PAYMENT_MODIFIER(shadowroute, struct shadow_route_data *, shadow_route_init, shadow_route_cb); static void direct_pay_override(struct payment *p) { /* The root has performed the search for a direct channel. */ struct payment *root = payment_root(p); struct direct_pay_data *d; struct channel_hint *hint = NULL; /* If we were unable to find a direct channel we don't need to do * anything. */ d = payment_mod_directpay_get_data(root); if (d->chan == NULL) return payment_continue(p); /* If we have a channel we need to make sure that it still has * sufficient capacity. Look it up in the channel_hints. */ for (size_t i=0; ichannel_hints); i++) { struct short_channel_id_dir *cur = &root->channel_hints[i].scid; if (short_channel_id_eq(&cur->scid, &d->chan->scid) && cur->dir == d->chan->dir) { hint = &root->channel_hints[i]; break; } } if (hint && hint->enabled && amount_msat_greater(hint->estimated_capacity, p->amount)) { /* Now build a route that consists only of this single hop */ p->route = tal_arr(p, struct route_hop, 1); p->route[0].amount = p->amount; p->route[0].delay = p->getroute->cltv; p->route[0].channel_id = hint->scid.scid; p->route[0].direction = hint->scid.dir; p->route[0].nodeid = *p->destination; p->route[0].style = ROUTE_HOP_TLV; plugin_log(p->plugin, LOG_DBG, "Found a direct channel (%s) with sufficient " "capacity, skipping route computation.", type_to_string(tmpctx, struct short_channel_id_dir, &hint->scid)); payment_set_step(p, PAYMENT_STEP_GOT_ROUTE); } payment_continue(p); } /* Now that we have the listpeers result for the root payment, let's search * for a direct channel that is a) connected and b) in state normal. We will * check the capacity based on the channel_hints in the override. */ static struct command_result *direct_pay_listpeers(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { struct listpeers_result *r = json_to_listpeers_result(tmpctx, buffer, toks); struct direct_pay_data *d = payment_mod_directpay_get_data(p); if (tal_count(r->peers) == 1) { struct listpeers_peer *peer = r->peers[0]; if (!peer->connected) goto cont; for (size_t i=0; ichannels); i++) { struct listpeers_channel *chan = r->peers[0]->channels[i]; if (!streq(chan->state, "CHANNELD_NORMAL")) continue; d->chan = tal(d, struct short_channel_id_dir); d->chan->scid = *chan->scid; d->chan->dir = *chan->direction; } } cont: direct_pay_override(p); return command_still_pending(cmd); } static void direct_pay_cb(struct direct_pay_data *d, struct payment *p) { struct out_req *req; /* Look up the direct channel only on root. */ if (p->step != PAYMENT_STEP_INITIALIZED) return payment_continue(p); req = jsonrpc_request_start(p->plugin, NULL, "listpeers", direct_pay_listpeers, direct_pay_listpeers, p); json_add_node_id(req->js, "id", p->destination); send_outreq(p->plugin, req); } static struct direct_pay_data *direct_pay_init(struct payment *p) { struct direct_pay_data *d = tal(p, struct direct_pay_data); d->chan = NULL; return d; } REGISTER_PAYMENT_MODIFIER(directpay, struct direct_pay_data *, direct_pay_init, direct_pay_cb); static struct command_result *waitblockheight_rpc_cb(struct command *cmd, const char *buffer, const jsmntok_t *toks, struct payment *p) { struct payment *subpayment; subpayment = payment_new(p, NULL, p, p->modifiers); payment_start(subpayment); payment_set_step(p, PAYMENT_STEP_RETRY); subpayment->why = tal_fmt(subpayment, "Retrying after waiting for blockchain sync."); payment_continue(p); return command_still_pending(cmd); } static void waitblockheight_cb(void *d, struct payment *p) { struct out_req *req; struct timeabs now = time_now(); struct timerel remaining; u32 blockheight = p->start_block; int failcode; const u8 *raw_message; if (p->step != PAYMENT_STEP_FAILED) return payment_continue(p); /* If we don't have an error message to parse we can't wait for blockheight. */ if (p->result == NULL) return payment_continue(p); if (time_after(now, p->deadline)) return payment_continue(p); failcode = p->result->failcode; raw_message = p->result->raw_message; remaining = time_between(p->deadline, now); if (failcode == 17 /* Former final_expiry_too_soon */) { blockheight = p->start_block + 1; } else { /* If it's incorrect_or_unknown_payment_details, that tells us * what height they're at */ struct amount_msat unused; const void *ptr = raw_message; if (!fromwire_incorrect_or_unknown_payment_details( ptr, &unused, &blockheight)) return payment_continue(p); } /* If we are already at the desired blockheight there is no point in * waiting, and it is likely just some other error. Notice that * start_block gets set by the initial getinfo call for each * attempt.*/ if (blockheight <= p->start_block) return payment_continue(p); plugin_log(p->plugin, LOG_INFORM, "Remote node appears to be on a longer chain, which causes " "CLTV timeouts to be incorrect. Waiting up to %" PRIu64 " seconds to catch up to block %d before retrying.", time_to_sec(remaining), blockheight); /* Set temporarily set the state of the payment to not failed, so * interim status queries don't show this as terminally failed. We're * in control for this payment so nobody else could be fooled by * this. The callback will set it to retry anyway. */ payment_set_step(p, PAYMENT_STEP_RETRY); req = jsonrpc_request_start(p->plugin, NULL, "waitblockheight", waitblockheight_rpc_cb, waitblockheight_rpc_cb, p); json_add_u32(req->js, "blockheight", blockheight); json_add_u32(req->js, "timeout", time_to_sec(remaining)); send_outreq(p->plugin, req); } REGISTER_PAYMENT_MODIFIER(waitblockheight, void *, NULL, waitblockheight_cb); /***************************************************************************** * presplit -- Early MPP splitter modifier. * * This splitter modifier is applied to the root payment, and splits the * payment into parts that are more likely to succeed right away. The * parameters are derived from probing the network for channel capacities, and * may be adjusted in future. */ /*By probing the capacity from a well-connected vantage point in the network * we found that the 80th percentile of capacities is >= 9765 sats. * * Rounding to 10e6 msats per part there is a ~80% chance that the payment * will go through without requiring further splitting. The fuzzing is * symmetric and uniformy distributed around this value, so this should not * change the success rate much. For the remaining 20% of payments we might * require a split to make the parts succeed, so we try only a limited number * of times before we split adaptively. * * Notice that these numbers are based on a worst case assumption that * payments from any node to any other node are equally likely, which isn't * really the case, so this is likely a lower bound on the success rate. * * As the network evolves these numbers are also likely to change. * * Finally, if applied trivially this splitter may end up creating more splits * than the sum of all channels can support, i.e., each split results in an * HTLC, and each channel has an upper limit on the number of HTLCs it'll * allow us to add. If the initial split would result in more than 1/3rd of * the total available HTLCs we clamp the number of splits to 1/3rd. We don't * use 3/3rds in order to retain flexibility in the adaptive splitter. */ #define MPP_TARGET_SIZE (10 * 1000 * 1000) #define PRESPLIT_MAX_HTLC_SHARE 3 static struct presplit_mod_data *presplit_mod_data_init(struct payment *p) { struct presplit_mod_data *d; if (p->parent == NULL) { d = tal(p, struct presplit_mod_data); d->disable = false; return d; } else { return payment_mod_presplit_get_data(p->parent); } } static u32 payment_max_htlcs(const struct payment *p) { struct channel_hint *h; u32 res = 0; for (size_t i = 0; i < tal_count(p->channel_hints); i++) { h = &p->channel_hints[i]; if (h->local && h->enabled) res += h->htlc_budget; } return res; } static bool payment_supports_mpp(struct payment *p) { if (p->invoice == NULL || p->invoice->features == NULL) return false; return feature_offered(p->invoice->features, OPT_BASIC_MPP); } /* Return fuzzed amount ~= target, but never exceeding max */ static struct amount_msat fuzzed_near(struct amount_msat target, struct amount_msat max) { s64 fuzz; struct amount_msat res = target; /* Somewhere within 25% of target please. */ fuzz = pseudorand(target.millisatoshis / 2) /* Raw: fuzz */ - target.millisatoshis / 4; /* Raw: fuzz */ res.millisatoshis = target.millisatoshis + fuzz; /* Raw: fuzz < msat */ if (amount_msat_greater(res, max)) res = max; return res; } static void presplit_cb(struct presplit_mod_data *d, struct payment *p) { struct payment *root = payment_root(p); if (d->disable || p->parent != NULL || !payment_supports_mpp(p)) return payment_continue(p); if (p->step == PAYMENT_STEP_ONION_PAYLOAD) { /* We need to tell the last hop the total we're going to * send. Presplit disables amount fuzzing, so we should always * get the exact value through. */ size_t lastidx = tal_count(p->createonion_request->hops) - 1; struct createonion_hop *hop = &p->createonion_request->hops[lastidx]; if (hop->style == ROUTE_HOP_TLV) { struct tlv_field **fields = &hop->tlv_payload->fields; tlvstream_set_tlv_payload_data( fields, root->payment_secret, root->amount.millisatoshis); /* Raw: onion payload */ } } else if (p->step == PAYMENT_STEP_INITIALIZED) { /* The presplitter only acts on the root and only in the first * step. */ size_t count = 0; u32 htlcs = payment_max_htlcs(p) / PRESPLIT_MAX_HTLC_SHARE; struct amount_msat target, amt = p->amount; /* We need to opt-in to the MPP sending facility no matter * what we do. That means setting all partids to a non-zero * value. */ root->partid++; /* Bump the next_partid as well so we don't have duplicate * partids. Not really necessary since the root payment whose * id could be reused will never reach the `sendonion` step, * but makes debugging a bit easier. */ root->next_partid++; if (htlcs == 0) { p->abort = true; return payment_fail( p, "Cannot attempt payment, we have no channel to " "which we can add an HTLC"); } else if (p->amount.millisatoshis / MPP_TARGET_SIZE > htlcs) /* Raw: division */ target.millisatoshis = p->amount.millisatoshis / htlcs; /* Raw: division */ else target = AMOUNT_MSAT(MPP_TARGET_SIZE); /* If we are already below the target size don't split it * either. */ if (amount_msat_greater(target, p->amount)) return payment_continue(p); /* Ok, we know we should split, so split here and then skip this * payment and start the children instead. */ while (!amount_msat_eq(amt, AMOUNT_MSAT(0))) { double multiplier; struct payment *c = payment_new(p, NULL, p, p->modifiers); /* Get ~ target, but don't exceed amt */ c->amount = fuzzed_near(target, amt); if (!amount_msat_sub(&amt, amt, c->amount)) plugin_err( p->plugin, "Cannot subtract %s from %s in splitter", type_to_string(tmpctx, struct amount_msat, &c->amount), type_to_string(tmpctx, struct amount_msat, &amt)); /* Now adjust the constraints so we don't multiply them * when splitting. */ multiplier = (double)c->amount.millisatoshis / (double)p->amount.millisatoshis; /* Raw: msat division. */ c->constraints.fee_budget.millisatoshis *= multiplier; /* Raw: Multiplication */ payment_start(c); count++; } p->result = NULL; p->route = NULL; p->why = tal_fmt( p, "Split into %zu sub-payments due to initial size (%s > %s)", count, type_to_string(tmpctx, struct amount_msat, &root->amount), type_to_string(tmpctx, struct amount_msat, &target)); payment_set_step(p, PAYMENT_STEP_SPLIT); plugin_log(p->plugin, LOG_INFORM, "%s", p->why); } payment_continue(p); } REGISTER_PAYMENT_MODIFIER(presplit, struct presplit_mod_data *, presplit_mod_data_init, presplit_cb); /***************************************************************************** * Adaptive splitter -- Split payment if we can't get it through. * * The adaptive splitter splits the amount of a failed payment in half, with * +/- 10% randomness, and then starts two attempts, one for either side of * the split. The goal is to find two smaller routes, that still adhere to our * constraints, but that can complete the payment. * * This modifier also checks whether we can split and still have enough HTLCs * available on the channels and aborts if that's no longer the case. */ #define MPP_ADAPTIVE_LOWER_LIMIT AMOUNT_MSAT(100 * 1000) static struct adaptive_split_mod_data *adaptive_splitter_data_init(struct payment *p) { struct adaptive_split_mod_data *d; if (p->parent == NULL) { d = tal(p, struct adaptive_split_mod_data); d->disable = false; d->htlc_budget = 0; return d; } else { return payment_mod_adaptive_splitter_get_data(p->parent); } } static void adaptive_splitter_cb(struct adaptive_split_mod_data *d, struct payment *p) { struct payment *root = payment_root(p); struct adaptive_split_mod_data *root_data = payment_mod_adaptive_splitter_get_data(root); if (d->disable) return payment_continue(p); if (!payment_supports_mpp(p) || root->abort) return payment_continue(p); if (p->parent == NULL && d->htlc_budget == 0) { /* Now that we potentially had an early splitter run, let's * update our htlc_budget that we own exclusively from now * on. We do this by subtracting the number of payment * attempts an eventual presplitter has already performed. */ struct payment_tree_result res; res = payment_collect_result(p); d->htlc_budget = payment_max_htlcs(p); if (res.attempts > d->htlc_budget) { p->abort = true; return payment_fail( p, "Cannot add %d HTLCs to our channels, we " "only have %d HTLCs available.", res.attempts, d->htlc_budget); } d->htlc_budget -= res.attempts; } if (p->step == PAYMENT_STEP_ONION_PAYLOAD) { /* We need to tell the last hop the total we're going to * send. Presplit disables amount fuzzing, so we should always * get the exact value through. */ size_t lastidx = tal_count(p->createonion_request->hops) - 1; struct createonion_hop *hop = &p->createonion_request->hops[lastidx]; if (hop->style == ROUTE_HOP_TLV) { struct tlv_field **fields = &hop->tlv_payload->fields; tlvstream_set_tlv_payload_data( fields, root->payment_secret, root->amount.millisatoshis); /* Raw: onion payload */ } } else if (p->step == PAYMENT_STEP_FAILED && !p->abort) { if (amount_msat_greater(p->amount, MPP_ADAPTIVE_LOWER_LIMIT)) { struct payment *a, *b; /* Random number in the range [90%, 110%] */ double rand = pseudorand_double() * 0.2 + 0.9; u64 mid = p->amount.millisatoshis / 2 * rand; /* Raw: multiplication */ bool ok; /* Use the start constraints, not the ones updated by routes and shadow-routes. */ struct payment_constraints *pconstraints = p->start_constraints; /* First check that splitting doesn't exceed our HTLC budget */ if (root_data->htlc_budget == 0) { root->abort = true; return payment_fail( p, "Cannot split payment any further without " "exceeding the maximum number of HTLCs " "allowed by our channels"); } a = payment_new(p, NULL, p, p->modifiers); b = payment_new(p, NULL, p, p->modifiers); a->amount.millisatoshis = mid; /* Raw: split. */ b->amount.millisatoshis -= mid; /* Raw: split. */ double multiplier = (double)a->amount.millisatoshis / (double)p->amount.millisatoshis; /* Raw: msat division */ assert(multiplier >= 0.4 && multiplier < 0.6); /* Adjust constraints since we don't want to double our * fee allowance when we split. */ a->constraints.fee_budget.millisatoshis = pconstraints->fee_budget.millisatoshis * multiplier; /* Raw: msat multiplication. */ ok = amount_msat_sub(&b->constraints.fee_budget, pconstraints->fee_budget, a->constraints.fee_budget); /* Should not fail, mid is less than 55% of original * amount. fee_budget_a <= 55% of fee_budget_p (parent * of the new payments).*/ assert(ok); payment_start(a); payment_start(b); p->step = PAYMENT_STEP_SPLIT; /* Take note that we now have an additional split that * may end up using an HTLC. */ root_data->htlc_budget--; } else { plugin_log(p->plugin, LOG_INFORM, "Lower limit of adaptive splitter reached " "(%s < %s), not splitting further.", type_to_string(tmpctx, struct amount_msat, &p->amount), type_to_string(tmpctx, struct amount_msat, &MPP_ADAPTIVE_LOWER_LIMIT)); } } payment_continue(p); } REGISTER_PAYMENT_MODIFIER(adaptive_splitter, struct adaptive_split_mod_data *, adaptive_splitter_data_init, adaptive_splitter_cb);