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libplugin-pay.c
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3927 lines (3408 loc) · 121 KB
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#include "config.h"
#include <ccan/mem/mem.h>
#include <ccan/tal/str/str.h>
#include <common/blindedpay.h>
#include <common/bolt11.h>
#include <common/clock_time.h>
#include <common/daemon.h>
#include <common/dijkstra.h>
#include <common/features.h>
#include <common/gossmap.h>
#include <common/gossmods_listpeerchannels.h>
#include <common/json_stream.h>
#include <common/memleak.h>
#include <common/random_select.h>
#include <common/route.h>
#include <common/trace.h>
#include <errno.h>
#include <inttypes.h>
#include <math.h>
#include <plugins/channel_hint.h>
#include <plugins/libplugin-pay.h>
#include <wire/peer_wire.h>
static struct gossmap *global_gossmap;
static bool got_gossmap;
static void init_gossmap(struct plugin *plugin)
{
global_gossmap
= notleak_with_children(gossmap_load(NULL,
GOSSIP_STORE_FILENAME,
plugin_gossmap_logcb,
plugin));
if (!global_gossmap)
plugin_err(plugin, "Could not load gossmap %s: %s",
GOSSIP_STORE_FILENAME, strerror(errno));
}
struct gossmap *get_raw_gossmap(struct payment *payment)
{
assert(!got_gossmap);
if (!global_gossmap)
init_gossmap(payment->plugin);
else
gossmap_refresh(global_gossmap);
return global_gossmap;
}
static struct gossmap *get_gossmap(struct payment *payment)
{
get_raw_gossmap(payment);
got_gossmap = true;
assert(payment->mods);
gossmap_apply_localmods(global_gossmap, payment->mods);
return global_gossmap;
}
static void put_gossmap(struct payment *payment)
{
assert(got_gossmap);
got_gossmap = false;
gossmap_remove_localmods(global_gossmap, payment->mods);
}
int libplugin_pay_poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
assert(!got_gossmap);
return daemon_poll(fds, nfds, timeout);
}
/* Only root has a non-NULL cmd ptr */
static struct command *payment_cmd(struct payment *p)
{
return payment_root(p)->cmd;
}
struct payment *payment_new(tal_t *ctx, struct command *cmd,
struct payment *parent,
struct channel_hint_set *channel_hints,
struct payment_modifier **mods)
{
struct payment *p = tal(ctx, struct payment);
static u64 next_id = 0;
p->children = tal_arr(p, struct payment *, 0);
p->parent = parent;
p->modifiers = mods;
p->cmd = cmd;
p->finished = false;
p->start_time = clock_time();
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;
p->invstring_used = false;
p->route = NULL;
p->temp_exclusion = NULL;
p->failroute_retry = false;
p->routetxt = NULL;
p->max_htlcs = UINT32_MAX;
p->aborterror = NULL;
p->on_payment_success = NULL;
p->on_payment_failure = NULL;
p->errorcode = 0;
/* Copy over the relevant pieces of information. */
if (parent != NULL) {
assert(cmd == NULL);
tal_arr_expand(&parent->children, p);
p->route_destination = parent->route_destination;
p->pay_destination = parent->pay_destination;
p->final_amount = parent->final_amount;
p->our_amount = parent->our_amount;
p->label = parent->label;
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->min_final_cltv_expiry = parent->min_final_cltv_expiry;
p->routes = parent->routes;
p->features = parent->features;
p->id = parent->id;
p->local_id = parent->local_id;
p->local_invreq_id = parent->local_invreq_id;
p->groupid = parent->groupid;
p->invstring = parent->invstring;
p->description = parent->description;
p->mods = parent->mods;
p->chainlag = parent->chainlag;
} else {
assert(cmd != NULL);
p->partid = 0;
p->next_partid = 1;
p->plugin = cmd->plugin;
p->excluded_nodes = tal_arr(p, struct node_id, 0);
p->id = next_id++;
p->description = NULL;
/* Caller must set this. */
p->local_id = NULL;
p->local_invreq_id = NULL;
p->groupid = 0;
p->mods = NULL;
p->chainlag = 0;
assert(channel_hints != NULL);
p->hints = channel_hints;
}
/* 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);
}
static const char *paymod_log_header(const tal_t *ctx,
struct payment *p)
{
const char *id = payment_cmd(p)->id;
if (strstarts(id, "\""))
return tal_strndup(ctx, id+1, strlen(id+1)-1);
return tal_strdup(ctx, id);
}
void
paymod_log(struct payment *p, enum log_level l, const char *fmt, ...)
{
char *txt;
va_list ap;
va_start(ap, fmt);
txt = tal_vfmt(tmpctx, fmt, ap);
va_end(ap);
plugin_log(p->plugin, l, "cmd %s partid %"PRIu32": %s",
paymod_log_header(tmpctx, p), p->partid, txt);
}
static void
paymod_err(struct payment *p, const char *fmt, ...)
{
char *txt;
va_list ap;
va_start(ap, fmt);
txt = tal_vfmt(tmpctx, fmt, ap);
va_end(ap);
plugin_err(p->plugin, "cmd %s partid %"PRIu32": %s",
paymod_log_header(tmpctx, p), p->partid, txt);
}
/* Generic handler for RPC failures that should end up failing the payment. */
static struct command_result *payment_rpc_failure(struct command *cmd,
const char *method,
const char *buffer,
const jsmntok_t *toks,
struct payment *p)
{
return payment_fail(p,
"Failing a partial payment due to a failed RPC call %s: %.*s",
method, toks->end - toks->start, buffer + toks->start);
}
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_accumulate(&res.sent, cres.sent))
paymod_err(
p,
"Number overflow summing partial payments: %s + %s",
fmt_amount_msat(tmpctx, res.sent),
fmt_amount_msat(tmpctx, 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_waitblockheight_cb(struct command *cmd,
const char *method,
const char *buffer,
const jsmntok_t *toks,
struct payment *p)
{
u32 syncheight;
json_scan(tmpctx, buffer, toks, "{blockheight:%}",
JSON_SCAN(json_to_u32, &syncheight));
paymod_log(p, LOG_DBG, "waitblockheight reports syncheight=%d",
syncheight);
p->chainlag = p->start_block - syncheight;
if (p->chainlag > 0)
paymod_log(p, LOG_INFORM,
"Starting the payment with chainlag=%d "
"(syncheight=%d < headercount=%d)",
p->chainlag, syncheight, p->start_block);
return payment_continue(p);
}
static struct command_result *
payment_getblockheight_success(struct command *cmd,
const char *method,
const char *buffer,
const jsmntok_t *toks,
struct payment *p)
{
struct out_req *req;
u32 blockcount, headercount;
json_scan(tmpctx, buffer, toks, "{blockcount:%,headercount:%}",
JSON_SCAN(json_to_u32, &blockcount),
JSON_SCAN(json_to_u32, &headercount));
paymod_log(p, LOG_DBG,
"Received getchaininfo blockcount=%d, headercount=%d",
blockcount, headercount);
p->start_block = headercount;
/* Now we just need to ask `lightningd` what height it has
* synced up to, and we remember that as chainlag. */
req = jsonrpc_request_start(cmd, "waitblockheight",
&payment_waitblockheight_cb,
&payment_rpc_failure, p);
json_add_u32(req->js, "blockheight", 0);
return send_outreq(req);
}
#define INVALID_BLOCKHEIGHT UINT32_MAX
static struct command_result *
payment_start_at_blockheight(struct payment *p, u32 blockheight)
{
struct payment *root = payment_root(p);
/* Should have been set in root payment, or propagated from root
* payment to all child payments. */
assert(p->local_id);
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->route_destination;
p->getroute->max_hops = ROUTING_MAX_HOPS;
p->getroute->cltv = root->min_final_cltv_expiry;
p->getroute->amount = p->our_amount;
p->start_constraints = tal_dup(p, struct payment_constraints, &p->constraints);
if (blockheight != INVALID_BLOCKHEIGHT) {
/* The caller knows the actual blockheight. */
p->start_block = blockheight;
return payment_continue(p);
}
if (p->parent) {
/* The parent should have a start block. */
p->start_block = p->parent->start_block;
return payment_continue(p);
}
/* Check with the backend what it believes the network's
* height to be. We'll base all of our offsets based on that
* height, allowing us to send while still syncing.
*/
struct out_req *req;
req = jsonrpc_request_start(payment_cmd(p), "getchaininfo",
&payment_getblockheight_success,
&payment_rpc_failure, p);
json_add_u32(req->js, "last_height", 0);
return send_outreq(req);
}
void payment_start(struct payment *p)
{
payment_start_at_blockheight(p, INVALID_BLOCKHEIGHT);
}
/**
* Notify subscribers of the `channel_hint` topic about a changed hint
*
* We share the channel_hints across payments, and across plugins, in order
* to maximize the context they have when performing payments.
*/
static void channel_hint_notify_core(struct plugin *plugin,
struct json_stream *js,
const char *fieldname,
const struct channel_hint *hint)
{
/* The timestamp used to decay the observation over time. */
channel_hint_to_json(fieldname, hint, js);
}
static void channel_hint_notify(struct plugin *plugin,
const struct channel_hint *hint)
{
struct json_stream *js =
plugin_notification_start_obs(plugin, "channel_hint_update");
/* Fake up the old "payload" style, *and* the old unwrapped style */
if (notification_deprecated_out_ok(plugin, "notification", "payload",
"v25.09", "v26.09")) {
json_add_string(js, "origin", "pay");
json_object_start(js, "payload");
channel_hint_notify_core(plugin, js, "channel_hint", hint);
json_object_end(js);
}
channel_hint_notify_core(plugin, js, "channel_hint_update", hint);
plugin_notification_end_obs(plugin, js);
}
static void channel_hints_update(struct payment *p,
const struct short_channel_id scid,
int direction, bool enabled, bool local,
const struct amount_msat *estimated_capacity,
const struct amount_msat overall_capacity,
u16 *htlc_budget)
{
struct payment *root = payment_root(p);
struct short_channel_id_dir *scidd =
tal(tmpctx, struct short_channel_id_dir);
struct channel_hint *hint;
scidd->scid = scid;
scidd->dir = direction;
/* Local channels must have an HTLC budget */
assert(!local || htlc_budget != NULL);
channel_hint_set_add(root->hints, clock_time().ts.tv_sec, scidd, enabled,
estimated_capacity, overall_capacity, htlc_budget);
hint = channel_hint_set_find(root->hints, scidd);
if (local) {
hint->local = tal_free(hint->local);
hint->local = tal(root->hints, struct local_hint);
hint->local->htlc_budget = *htlc_budget;
}
/* If the channel is marked as enabled it must have an estimate. */
assert(!enabled || estimated_capacity != NULL);
if (hint != NULL) {
paymod_log(p, LOG_DBG,
"Updated a channel hint for %s: "
"enabled %s, "
"estimated capacity %s",
fmt_short_channel_id_dir(tmpctx, &hint->scid),
hint->enabled ? "true" : "false",
hint->enabled ? fmt_amount_msat(tmpctx, hint->estimated_capacity) : "UNKNOWN");
channel_hint_notify(p->plugin, 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->our_amount)) {
paymod_log(
p,
LOG_BROKEN,
"gossipd returned a route with a negative fee: sending %s "
"to deliver %s",
fmt_amount_msat(tmpctx, p->route[0].amount),
fmt_amount_msat(tmpctx, p->our_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_deduct(&cons->fee_budget, delta_fee))
return false;
cons->cltv_budget -= delta_cltv;
return true;
}
static struct channel_hint *payment_chanhints_get(struct payment *p,
struct route_hop *h)
{
struct payment *root = payment_root(p);
struct short_channel_id_dir scidd = {.scid = h->scid, .dir = h->direction};
return channel_hint_set_find(root->hints, &scidd);
}
/* 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.
*/
static bool payment_chanhints_apply_route(struct payment *p)
{
bool apply;
struct route_hop *curhop;
struct channel_hint *curhint;
struct payment *root = payment_root(p);
assert(p->route != NULL);
/* First round: make sure we can cleanly apply the update. */
for (size_t i = 0; i < tal_count(p->route); i++) {
curhop = &p->route[i];
curhint = payment_chanhints_get(root, curhop);
/* If we don't have a hint we can't fail updating it. */
if (!curhint)
continue;
/* For local channels we check that we don't overwhelm
* them with too many HTLCs. */
apply = (!curhint->local) ||
(curhint->local->htlc_budget > 0);
/* For all channels we check that they have a
* sufficiently large estimated capacity to have some
* chance of succeeding. */
apply &= amount_msat_greater_eq(curhint->estimated_capacity,
curhop->amount);
if (!apply) {
/* This can happen in case of multiple
* concurrent getroute calls using the
* same channel_hints, no biggy, it's
* an estimation anyway. */
paymod_log(p, LOG_DBG,
"Could not update the channel hint "
"for %s. Could be a concurrent "
"`getroute` call.",
fmt_short_channel_id_dir(tmpctx,
&curhint->scid));
paymod_log(
p, LOG_DBG,
"Capacity: estimated_capacity=%s, hop_amount=%s. "
"local=%s%s",
fmt_amount_msat(tmpctx, curhint->estimated_capacity),
fmt_amount_msat(tmpctx, curhop->amount),
curhint->local ? "Y" : "N",
curhint->local ?
tal_fmt(tmpctx, " HTLC Budget: htlc_budget=%d",
curhint->local->htlc_budget) : "");
return false;
}
}
/* Second round: apply the changes, now that we know they'll succeed. */
for (size_t i = 0; i < tal_count(p->route); i++) {
curhop = &p->route[i];
curhint = payment_chanhints_get(root, curhop);
if (!curhint)
continue;
/* Update the number of htlcs for any local
* channel in the route */
if (curhint->local) {
curhint->local->htlc_budget--;
}
if (!amount_msat_deduct(&curhint->estimated_capacity,
curhop->amount)) {
/* Given our preemptive test
* above, this should never
* happen either. */
abort();
}
}
return true;
}
/* Undo route changes above */
static void payment_chanhints_unapply_route(struct payment *p)
{
struct payment *root = payment_root(p);
for (size_t i = 0; i < tal_count(p->route); i++) {
struct route_hop *curhop;
struct channel_hint *curhint;
curhop = &p->route[i];
curhint = payment_chanhints_get(root, curhop);
if (!curhint)
continue;
/* Update the number of htlcs for any local
* channel in the route */
if (curhint->local)
curhint->local->htlc_budget++;
if (!amount_msat_accumulate(&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();
}
}
}
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 channel_hint_map_iter iter;
struct short_channel_id_dir *res =
tal_arr(ctx, struct short_channel_id_dir, 0);
for (hint = channel_hint_map_first(root->hints->hints, &iter);
hint;
hint = channel_hint_map_next(root->hints->hints, &iter)) {
if (!hint->enabled)
tal_arr_expand(&res, hint->scid);
else if (amount_msat_greater(p->our_amount,
hint->estimated_capacity))
tal_arr_expand(&res, hint->scid);
else if (hint->local && hint->local->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;
}
/* FIXME: This is slow! */
static bool dst_is_excluded(const struct gossmap *gossmap,
const struct gossmap_chan *c,
int dir,
const struct node_id *nodes)
{
struct node_id dstid;
/* Premature optimization */
if (!tal_count(nodes))
return false;
gossmap_node_get_id(gossmap, gossmap_nth_node(gossmap, c, !dir),
&dstid);
for (size_t i = 0; i < tal_count(nodes); i++) {
if (node_id_eq(&dstid, &nodes[i]))
return true;
}
return false;
}
static bool payment_route_check(const struct gossmap *gossmap,
const struct gossmap_chan *c,
int dir,
struct amount_msat amount,
struct payment *p)
{
struct short_channel_id_dir scidd;
const struct channel_hint *hint;
if (dst_is_excluded(gossmap, c, dir, payment_root(p)->excluded_nodes))
return false;
if (dst_is_excluded(gossmap, c, dir, p->temp_exclusion))
return false;
scidd.scid = gossmap_chan_scid(gossmap, c);
scidd.dir = dir;
hint = channel_hint_set_find(payment_root(p)->hints, &scidd);
if (!hint)
return true;
paymod_log(p, LOG_DBG,
"Checking hint {.scid=%s, .enabled=%d, .estimate=%s}",
fmt_short_channel_id_dir(tmpctx, &hint->scid), hint->enabled,
fmt_amount_msat(tmpctx, hint->estimated_capacity));
if (!hint->enabled)
return false;
if (amount_msat_greater_eq(amount, hint->estimated_capacity))
/* We exclude on equality because we've set the
* estimate to the smallest failed attempt. */
return false;
if (hint->local && hint->local->htlc_budget == 0)
/* If we cannot add any HTLCs to the channel we
* shouldn't look for a route through that channel */
return false;
return true;
}
static bool payment_route_can_carry(const struct gossmap *map,
const struct gossmap_chan *c,
int dir,
struct amount_msat amount,
struct payment *p)
{
if (!route_can_carry(map, c, dir, amount, p))
return false;
return payment_route_check(map, c, dir, amount, p);
}
static bool payment_route_can_carry_even_disabled(const struct gossmap *map,
const struct gossmap_chan *c,
int dir,
struct amount_msat amount,
struct payment *p)
{
if (!route_can_carry_even_disabled(map, c, dir, amount, p))
return false;
return payment_route_check(map, c, dir, amount, p);
}
/* Rene Pickhardt:
*
* Btw the linear term of the Taylor series of -log((c+1-x)/(c+1)) is 1/(c+1)
* meaning that another suitable Weight for Dijkstra would be amt/(c+1) +
* \mu*fee(amt) which is the linearized version which for small amounts and
* suitable value of \mu should be good enough)
*/
static double capacity_bias(const struct gossmap *map,
const struct gossmap_chan *c,
int dir,
struct amount_msat amount)
{
u64 amtmsat = amount.millisatoshis; /* Raw: lengthy math */
double capmsat;
/* Can fail in theory if gossmap changed underneath. */
capmsat = (double)gossmap_chan_get_capacity(map, c).millisatoshis; /* Raw: log */
return -log((capmsat + 1 - amtmsat) / (capmsat + 1));
}
/* Prioritize costs over distance, but bias to larger channels. */
static u64 route_score(struct amount_msat fee,
struct amount_msat risk,
struct amount_msat total,
int dir,
const struct gossmap_chan *c)
{
double score;
struct amount_msat msat;
/* These two are comparable, so simply sum them. */
if (!amount_msat_add(&msat, fee, risk))
msat = AMOUNT_MSAT(-1ULL);
/* Slight tiebreaker bias: 1 msat per distance */
if (!amount_msat_accumulate(&msat, AMOUNT_MSAT(1)))
msat = AMOUNT_MSAT(-1ULL);
/* Percent penalty at different channel capacities:
* 1%: 1%
* 10%: 11%
* 25%: 29%
* 50%: 69%
* 75%: 138%
* 90%: 230%
* 95%: 300%
* 99%: 461%
*/
score = (capacity_bias(global_gossmap, c, dir, total) + 1)
* msat.millisatoshis; /* Raw: Weird math */
if (score != score || score > 0xFFFFFFFF)
return 0xFFFFFFFF;
/* Cast unnecessary, but be explicit! */
return (u64)score;
}
static struct route_hop *route(const tal_t *ctx,
struct gossmap *gossmap,
const struct gossmap_node *src,
const struct gossmap_node *dst,
struct amount_msat amount,
u32 final_delay,
double riskfactor,
size_t max_hops,
struct payment *p,
const char **errmsg)
{
const struct dijkstra *dij;
struct route_hop *r;
bool (*can_carry)(const struct gossmap *,
const struct gossmap_chan *,
int,
struct amount_msat,
struct payment *);
can_carry = payment_route_can_carry;
dij = dijkstra(tmpctx, gossmap, dst, amount, riskfactor,
can_carry, route_score, p);
r = route_from_dijkstra(ctx, gossmap, dij, src, amount, final_delay);
if (!r) {
/* Try using disabled channels too */
/* FIXME: is there somewhere we can annotate this for paystatus? */
can_carry = payment_route_can_carry_even_disabled;
dij = dijkstra(tmpctx, gossmap, dst, amount, riskfactor,
can_carry, route_score, p);
r = route_from_dijkstra(ctx, gossmap, dij, src,
amount, final_delay);
if (!r) {
*errmsg = "No path found";
return NULL;
}
}
/* If it's too far, fall back to using shortest path. */
if (tal_count(r) > max_hops) {
tal_free(r);
/* FIXME: is there somewhere we can annotate this for paystatus? */
dij = dijkstra(tmpctx, gossmap, dst, amount, riskfactor,
can_carry, route_score_shorter, p);
r = route_from_dijkstra(ctx, gossmap, dij, src,
amount, final_delay);
if (!r) {
*errmsg = "No path found";
return NULL;
}
/* If it's still too far, fail. */
if (tal_count(r) > max_hops) {
*errmsg = tal_fmt(ctx, "Shortest path found was length %zu",
tal_count(r));
return tal_free(r);
}
}
*errmsg = NULL;
return r;
}
static struct command_result *payment_getroute(struct payment *p)
{
const struct gossmap_node *dst, *src;
struct amount_msat fee;
const char *errstr;
struct gossmap *gossmap;
/* If we retry the getroute call we might already have a route, so
* free an eventual stale route. */
p->route = tal_free(p->route);
gossmap = get_gossmap(p);
dst = gossmap_find_node(gossmap, p->getroute->destination);
if (!dst) {
put_gossmap(p);
return payment_fail(
p, "Unknown destination %s",
fmt_node_id(tmpctx, p->getroute->destination));
}
/* If we don't exist in gossip, routing can't happen. */
src = gossmap_find_node(gossmap, p->local_id);
if (!src) {
put_gossmap(p);
return payment_fail(p, "We don't have any channels");
}
p->route = route(p, gossmap, src, dst, p->getroute->amount, p->getroute->cltv,
p->getroute->riskfactorppm / 1000000.0, p->getroute->max_hops,
p, &errstr);
put_gossmap(p);
if (!p->route) {
return payment_fail(p, "%s", errstr);
}
/* OK, now we *have* a route */
p->step = PAYMENT_STEP_GOT_ROUTE;
if (tal_count(p->route) == 0) {
payment_root(p)->abort = true;
return payment_fail(p, "Empty route returned by getroute, are you "
"trying to pay yourself?");
}
fee = payment_route_fee(p);
/* Ensure that our fee and CLTV budgets are respected. */
if (amount_msat_greater(fee, p->constraints.fee_budget)) {
p->route = tal_free(p->route);
return payment_fail(
p, "Fee exceeds our fee budget: %s > %s, discarding route",
fmt_amount_msat(tmpctx, fee),
fmt_amount_msat(tmpctx, p->constraints.fee_budget));
}
if (p->route[0].delay > p->constraints.cltv_budget) {
u32 delay = p->route[0].delay;
p->route = tal_free(p->route);
return payment_fail(p, "CLTV delay exceeds our CLTV budget: %d > %d",
delay, p->constraints.cltv_budget);
}
/* 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)) {
paymod_log(p, 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 */
return payment_continue(p);
}
/**
* Compute the total sum of balances. Limits the maximum size we can
* pay as a preflight test. Returns `false` on errors, otherwise
* `sum` contains the sum of all channel balances.*/
static bool payment_listpeerchannels_balance_sum(struct payment *p,
const char *buf,
const jsmntok_t *toks,
struct amount_msat *sum)
{
*sum = AMOUNT_MSAT(0);
const jsmntok_t *channels, *channel;
struct amount_msat spendable;
bool connected;
size_t i;
const char *err;
channels = json_get_member(buf, toks, "channels");
json_for_each_arr(i, channel, channels)
{
err = json_scan(tmpctx, buf, channel,
"{spendable_msat?:%,peer_connected:%}",
JSON_SCAN(json_to_msat, &spendable),
JSON_SCAN(json_to_bool, &connected));
if (err) {
paymod_log(p, LOG_UNUSUAL,
"Bad listpeerchannels.channels %zu: %s", i,
err);
return false;
}
if (!amount_msat_accumulate(sum, spendable)) {
paymod_log(
p, LOG_BROKEN,
"Integer sum overflow summing spendable amounts.");
return false;
}
}
return true;
}
static struct command_result *
payment_listpeerchannels_success(struct command *cmd,
const char *method,
const char *buffer,
const jsmntok_t *toks,
struct payment *p)
{
/* The maximum amount we may end up trying to send. This
* includes the value and the full fee budget. If the
* available funds are below this, we emit a warning. */
struct amount_msat maxrequired, spendable;
if (!amount_msat_add(&maxrequired, p->getroute->amount,
p->constraints.fee_budget)) {
paymod_log(p, LOG_BROKEN,
"amount_msat overflow computing the fee budget");
return payment_getroute(p);
}
p->mods = gossmods_from_listpeerchannels(
p, p->local_id, buffer, toks, true, gossmod_add_localchan, NULL);
if (!payment_listpeerchannels_balance_sum(p, buffer, toks,
&spendable)) {
paymod_log(p, LOG_UNUSUAL,
"Unable to get total spendable amount from "
"listpeerchannels. Skipping affordability check.");