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c0d70cdfc7
core-lightning/plugins/libplugin-pay.c
Christian Decker c0d70cdfc7 paymod: Add invariant verification for constraints on shadowroute 
This was highlighted in #3851, so I added an assertion. After the rewrite in
the next commit we would simply skip if any of the constraints were not
maintained, but this serves as the canary in the coalmine, so we don't paper over.
2020-07-23 10:14:21 +09:30

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#include <bitcoin/preimage.h>
#include <ccan/array_size/array_size.h>
#include <ccan/tal/str/str.h>
#include <common/json_stream.h>
#include <common/pseudorand.h>
#include <common/type_to_string.h>
#include <plugins/libplugin-pay.h>
#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;
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;
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) {
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);
}
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; i<tal_count(chans); i++)
json_add_short_channel_id_dir(js, NULL, &chans[i]);
/* Now also exclude nodes that we think have failed. */
nodes = payment_get_excluded_nodes(tmpctx, p);
for (size_t i=0; i<tal_count(nodes); i++)
json_add_node_id(js, NULL, &nodes[i]);
json_array_end(js);
}
static void payment_getroute(struct payment *p)
{
struct out_req *req;
req = jsonrpc_request_start(p->plugin, 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,
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; i<tal_count(root->channel_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;
tal_arr_expand(&root->channel_hints, hint);
}
/* 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;
}
static struct command_result *
payment_waitsendpay_finished(struct command *cmd, const char *buffer,
const jsmntok_t *toks, struct payment *p)
{
struct payment *root;
struct route_hop *hop;
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);
}
root = payment_root(p);
payment_chanhints_apply_route(p, true);
/* Either we have no erring_index, or it must be a correct index into
* p->route. 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,
* since the hop consists of the processing node, but the payload for
* the next hop. In addition there is a class of onion-related errors
* that are reported by the previous hop to the one erring, since the
* erring node couldn't read the onion in the first place.
*/
assert(p->result->erring_index == NULL ||
*p->result->erring_index - 1 < tal_count(p->route));
switch (p->result->failcode) {
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. */
assert(*p->result->erring_index < tal_count(p->route));
hop = &p->route[*p->result->erring_index];
channel_hints_update(root, &hop->channel_id, hop->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. */
assert(*p->result->erring_index < tal_count(p->route));
hop = &p->route[*p->result->erring_index];
struct amount_msat est = {
.millisatoshis = hop->amount.millisatoshis * 0.75}; /* Raw: Multiplication */
channel_hints_update(root, &hop->channel_id, hop->direction,
true, est);
break;
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:
case WIRE_INVALID_ONION_VERSION:
case WIRE_INVALID_ONION_HMAC:
case WIRE_INVALID_ONION_KEY:
#if EXPERIMENTAL_FEATURES
case WIRE_INVALID_ONION_BLINDING:
#endif
/* These are reported by the last hop, i.e., the destination of hop i-1. */
assert(*p->result->erring_index - 1 < tal_count(p->route));
hop = &p->route[*p->result->erring_index - 1];
tal_arr_expand(&root->excluded_nodes, hop->nodeid);
break;
case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
p->result->code = PAY_DESTINATION_PERM_FAIL;
root->abort = true;
case WIRE_MPP_TIMEOUT:
/* These are permanent failures that should abort all of our
* attempts right away. We'll still track pending partial
* payments correctly, just not start new ones. */
root->abort = true;
break;
case WIRE_AMOUNT_BELOW_MINIMUM:
case WIRE_EXPIRY_TOO_FAR:
case WIRE_EXPIRY_TOO_SOON:
case WIRE_FEE_INSUFFICIENT:
case WIRE_INCORRECT_CLTV_EXPIRY:
case WIRE_FINAL_INCORRECT_CLTV_EXPIRY:
/* These are issues that are due to gossipd being out of date,
* we ignore them here, and wait for gossipd to adjust
* instead. */
break;
case WIRE_FINAL_INCORRECT_HTLC_AMOUNT:
/* These are symptoms of intermediate hops tampering with the
* payment. */
hop = &p->route[*p->result->erring_index];
plugin_log(
p->plugin, LOG_UNUSUAL,
"Node %s reported an incorrect HTLC amount, this could be "
"a prior hop messing with the amounts.",
type_to_string(tmpctx, struct node_id, &hop->nodeid));
break;
}
payment_fail(p, "%s", p->result->message);
return command_still_pending(cmd);
}
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; i<tal_count(secrets); i++)
json_add_secret(req->js, 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; i<tal_count(p->children); 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; i<tal_count(p->children); 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;
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");
assert(spendsats != NULL && scid != NULL && dir != NULL);
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);
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)
{
if (p->parent != NULL) {
return payment_mod_shadowroute_get_data(p->parent);
} else {
struct shadow_route_data *d = tal(p, struct shadow_route_data);
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;
/* 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");
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)
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_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) {
bool ok;
/* Ok, we found an extension, let's add it. */
d->destination = best->pubkey;
/* Apply deltas to the constraints in the shadow route so we
* don't overshoot our 1/4th target. */
if (!payment_constraints_update(&d->constraints, best_fee,
best->cltv_expiry_delta)) {
best = NULL;
goto next;
}
/* Now do the same to the payment constraints so other
* modifiers don't do it either. */
ok = payment_constraints_update(&p->constraints, best_fee,
best->cltv_expiry_delta);
/* And now the thing that caused all of this: adjust the call
* to getroute. */
if (d->fuzz_amount) {
/* Only fuzz the amount to route to the destination if
* we didn't opt-out earlier. */
ok &= amount_msat_add(&p->getroute->amount,
p->getroute->amount, best_fee);
}
p->getroute->cltv += best->cltv_expiry_delta;
assert(ok);
}
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; i<tal_count(root->channel_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; i<tal_count(peer->channels); 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.
*/
#define MPP_TARGET_SIZE (10 * 1000 * 1000)
#define MPP_TARGET_MSAT AMOUNT_MSAT(MPP_TARGET_SIZE)
#define MPP_TARGET_FUZZ ( 1 * 1000 * 1000)
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 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);
}
static void presplit_cb(struct presplit_mod_data *d, struct payment *p)
{
struct payment *root = payment_root(p);
struct amount_msat amt = root->amount;
if (d->disable)
return payment_continue(p);
if (!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 == root && p->step == PAYMENT_STEP_INITIALIZED) {
/* The presplitter only acts on the root and only in the first
* step. */
size_t count = 0;
/* 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++;
/* If we are already below the target size don't split it
* either. */
if (amount_msat_greater(MPP_TARGET_MSAT, 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))) {
struct payment *c =
payment_new(p, NULL, p, p->modifiers);
/* Pseudorandom number in the range [-1, 1]. */
double rand = pseudorand_double() * 2 - 1;
double multiplier;
c->amount.millisatoshis = rand * MPP_TARGET_FUZZ + MPP_TARGET_SIZE; /* Raw: Multiplication */
/* Clamp the value to the total amount, so the fuzzing
* doesn't go above the total. */
if (amount_msat_greater(c->amount, amt))
c->amount = amt;
multiplier =
(double)c->amount.millisatoshis / (double)p->amount.millisatoshis; /* Raw: msat division. */
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. */
c->constraints.fee_budget.millisatoshis *= multiplier; /* Raw: Multiplication */
payment_start(c);
count++;
}
p->step = PAYMENT_STEP_SPLIT;
p->end_time = time_now();
p->why = tal_fmt(
p,
"Split into %zu sub-payments due to initial size (%s > "
"%dmsat)",
count,
type_to_string(tmpctx, struct amount_msat, &root->amount),
MPP_TARGET_SIZE);
plugin_log(p->plugin, LOG_INFORM, "%s", p->why);
p->result = NULL;
p->route = NULL;
}
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.
*/
#define MPP_ADAPTIVE_LOWER_LIMIT AMOUNT_MSAT(100 * 1000)
static struct presplit_mod_data *adaptive_splitter_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 void adaptive_splitter_cb(struct presplit_mod_data *d, struct payment *p)
{
struct payment *root = payment_root(p);
if (d->disable)
return payment_continue(p);
if (!payment_supports_mpp(p) || root->abort)
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_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;
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. */
/* Adjust constraints since we don't want to double our
* fee allowance when we split. */
a->constraints.fee_budget.millisatoshis *= (double)a->amount.millisatoshis / (double)p->amount.millisatoshis; /* Raw: msat division. */
ok = amount_msat_sub(&b->constraints.fee_budget,
p->constraints.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;
} 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 presplit_mod_data *,
adaptive_splitter_data_init, adaptive_splitter_cb);
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