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askrene: simply fail if a flow amount exceeds 64 bits.

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Rather than handling failure, simply report and exit the plugin.
Simplifies error handling.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2024-08-07 11:19:54 +09:30
parent 7bf399cac5
commit 1db5cf6dea
3 changed files with 69 additions and 88 deletions
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132
plugins/askrene/flow.c
View file

@ -14,7 +14,9 @@
#define SUPERVERBOSE_ENABLED 1
#endif
struct amount_msat *tal_flow_amounts(const tal_t *ctx, const struct flow *flow)
struct amount_msat *tal_flow_amounts(const tal_t *ctx,
struct plugin *plugin,
const struct flow *flow)
{
const size_t pathlen = tal_count(flow->path);
struct amount_msat *amounts = tal_arr(ctx, struct amount_msat, pathlen);
@ -24,14 +26,15 @@ struct amount_msat *tal_flow_amounts(const tal_t *ctx, const struct flow *flow)
const struct half_chan *h = flow_edge(flow, i + 1);
amounts[i] = amounts[i + 1];
if (!amount_msat_add_fee(&amounts[i], h->base_fee,
h->proportional_fee))
goto function_fail;
h->proportional_fee)) {
plugin_err(plugin, "Could not add fee %u/%u to amount %s in %i/%zu",
h->base_fee, h->proportional_fee,
fmt_amount_msat(tmpctx, &amounts[i+1]),
i, pathlen);
}
}
return amounts;
function_fail:
return tal_free(amounts);
}
const char *fmt_flows(const tal_t *ctx, const struct gossmap *gossmap,
@ -168,39 +171,21 @@ flow_maximum_deliverable(struct amount_msat *max_deliverable,
// }
/* How much do we deliver to destination using this set of routes */
bool flowset_delivers(struct amount_msat *delivers, struct flow **flows)
struct amount_msat flowset_delivers(struct plugin *plugin,
struct flow **flows)
{
struct amount_msat final = AMOUNT_MSAT(0);
for (size_t i = 0; i < tal_count(flows); i++) {
if (!amount_msat_add(&final, flows[i]->amount, final))
return false;
if (!amount_msat_add(&final, flows[i]->amount, final)) {
plugin_err(plugin, "Could not add flowsat %s to %s (%zu/%zu)",
fmt_amount_msat(tmpctx, flows[i]->amount),
fmt_amount_msat(tmpctx, final),
i, tal_count(flows));
}
}
*delivers = final;
return true;
return final;
}
/* Checks if the flows satisfy the liquidity bounds imposed by the known maximum
* liquidity and pending HTLCs.
*
* FIXME The function returns false even in the case of failure. The caller has
* no way of knowing the difference between a failure of evaluation and a
* negative answer. */
// static bool check_liquidity_bounds(struct flow **flows,
// const struct gossmap *gossmap,
// struct chan_extra_map *chan_extra_map)
// {
// bool check = true;
// for (size_t i = 0; i < tal_count(flows); ++i) {
// struct amount_msat max_deliverable;
// if (!flow_maximum_deliverable(&max_deliverable, flows[i],
// gossmap, chan_extra_map))
// return false;
// struct amount_msat delivers = flow_delivers(flows[i]);
// check &= amount_msat_less_eq(delivers, max_deliverable);
// }
// return check;
// }
/* Compute the prob. of success of a set of concurrent set of flows.
*
* IMPORTANT: this is not simply the multiplication of the prob. of success of
@ -226,7 +211,9 @@ struct chan_inflight_flow
// TODO(eduardo): here chan_extra_map should be const
// TODO(eduardo): here flows should be const
double flowset_probability(const tal_t *ctx, struct flow **flows,
double flowset_probability(const tal_t *ctx,
struct plugin *plugin,
struct flow **flows,
const struct gossmap *const gossmap,
struct chan_extra_map *chan_extra_map, char **fail)
{
@ -250,14 +237,6 @@ double flowset_probability(const tal_t *ctx, struct flow **flows,
const struct flow *f = flows[i];
const size_t pathlen = tal_count(f->path);
struct amount_msat *amounts = tal_flow_amounts(this_ctx, f);
if (!amounts)
{
if (fail)
*fail = tal_fmt(
ctx,
"failed to compute amounts along the path");
goto function_fail;
}
for (size_t j = 0; j < pathlen; ++j) {
const struct chan_extra_half *h =
@ -313,59 +292,50 @@ double flowset_probability(const tal_t *ctx, struct flow **flows,
return -1;
}
bool flow_spend(struct amount_msat *ret, struct flow *flow)
struct amount_msat flow_spend(struct plugin *plugin, const struct flow *flow)
{
assert(ret);
assert(flow);
const size_t pathlen = tal_count(flow->path);
struct amount_msat spend = flow->amount;
for (int i = (int)pathlen - 1; i >= 0; i--) {
const struct half_chan *h = flow_edge(flow, i);
if (!amount_msat_add_fee(&spend, h->base_fee,
h->proportional_fee))
goto function_fail;
h->proportional_fee)) {
plugin_err(plugin, "Could not add fee %u/%u to amount %s in %i/%zu",
h->base_fee, h->proportional_fee,
fmt_amount_msat(tmpctx, &amounts[i]),
i, pathlen);
}
}
*ret = spend;
return true;
function_fail:
return false;
return spend;
}
bool flow_fee(struct amount_msat *ret, struct flow *flow)
struct amount_msat flow_fee(struct plugin *plugin, const struct flow *flow)
{
assert(ret);
assert(flow);
struct amount_msat spend = flow_spend(plugin, flow);
struct amount_msat fee;
struct amount_msat spend;
if (!flow_spend(&spend, flow))
goto function_fail;
if (!amount_msat_sub(&fee, spend, flow->amount))
goto function_fail;
if (!amount_msat_sub(&fee, spend, flow->amount)) {
plugin_err(plugin, "Could not subtract %s from %s for fee",
fmt_amount_msat(tmpctx, flow->amount),
fmt_amount_msat(tmpctx, spend));
}
*ret = fee;
return true;
function_fail:
return false;
return fee;
}
bool flowset_fee(struct amount_msat *ret, struct flow **flows)
struct amount_msat flowset_fee(struct plugin *plugin, struct flow **flows)
{
assert(ret);
assert(flows);
struct amount_msat fee = AMOUNT_MSAT(0);
for (size_t i = 0; i < tal_count(flows); i++) {
struct amount_msat this_fee;
if (!flow_fee(&this_fee, flows[i]))
return false;
if (!amount_msat_add(&fee, this_fee, fee))
return false;
struct amount_msat this_fee = flow_fee(plugin, flows[i]);
if (!amount_msat_add(&fee, this_fee, fee)) {
plugin_err(plugin, "Could not add %s to %s for flowset fee",
fmt_amount_msat(tmpctx, this_fee),
fmt_amount_msat(tmpctx, fee));
}
}
*ret = fee;
return true;
return fee;
}
/* Helper to access the half chan at flow index idx */
@ -396,7 +366,9 @@ bool flow_assign_delivery(struct flow *flow, const struct gossmap *gossmap,
* IMPORTANT: flow->success_prob is misleading, because that's the prob. of
* success provided that there are no other flows in the current MPP flow set.
* */
double flow_probability(struct flow *flow, const struct gossmap *gossmap,
double flow_probability(const struct flow *flow,
struct plugin *plugin,
const struct gossmap *gossmap,
struct chan_extra_map *chan_extra_map)
{
assert(flow);
@ -417,8 +389,12 @@ double flow_probability(struct flow *flow, const struct gossmap *gossmap,
if (prob < 0)
goto function_fail;
if (!amount_msat_add_fee(&spend, h->base_fee,
h->proportional_fee))
goto function_fail;
h->proportional_fee)) {
plugin_err(plugin, "Could not add fee %u/%u to amount %s in %i/%zu",
h->base_fee, h->proportional_fee,
fmt_amount_msat(tmpctx, spend),
i, pathlen);
}
}
return prob;

17
plugins/askrene/flow.h
View file

@ -44,21 +44,24 @@ double flowset_probability(const tal_t *ctx, struct flow **flows,
struct chan_extra_map *chan_extra_map, char **fail);
/* How much do we need to send to make this flow arrive. */
bool flow_spend(struct amount_msat *ret, struct flow *flow);
struct amount_msat flow_spend(struct plugin *plugin, const struct flow *flow);
/* How much do we pay in fees to make this flow arrive. */
bool flow_fee(struct amount_msat *ret, struct flow *flow);
struct amount_msat flow_fee(struct plugin *plugin, const struct flow *flow);
bool flowset_fee(struct amount_msat *fee, struct flow **flows);
struct amount_msat flowset_fee(struct plugin *plugin, struct flow **flows);
bool flowset_delivers(struct amount_msat *delivers, struct flow **flows);
struct amount_msat flowset_delivers(struct plugin *plugin,
struct flow **flows);
static inline struct amount_msat flow_delivers(const struct flow *flow)
{
return flow->amount;
}
struct amount_msat *tal_flow_amounts(const tal_t *ctx, const struct flow *flow);
struct amount_msat *tal_flow_amounts(const tal_t *ctx,
struct plugin *plugin,
const struct flow *flow);
/* FIXME: remove */
enum askrene_errorcode {
@ -85,7 +88,9 @@ bool flow_assign_delivery(struct flow *flow, const struct gossmap *gossmap,
struct chan_extra_map *chan_extra_map,
struct amount_msat requested_amount);
double flow_probability(struct flow *flow, const struct gossmap *gossmap,
double flow_probability(const struct flow *flow,
struct plugin *plugin,
const struct gossmap *gossmap,
struct chan_extra_map *chan_extra_map);
u64 flow_delay(const struct flow *flow);

8
plugins/askrene/mcf.c
View file

@ -1184,6 +1184,7 @@ static inline uint64_t pseudorand_interval(uint64_t a, uint64_t b)
* gossmap that corresponds to this flow. */
static struct flow **
get_flow_paths(const tal_t *ctx, const struct gossmap *gossmap,
struct plugin *plugin,
const bitmap *disabled,
// chan_extra_map cannot be const because we use it to keep
@ -1354,10 +1355,9 @@ get_flow_paths(const tal_t *ctx, const struct gossmap *gossmap,
// accuracy
struct amount_msat delivered = amount_msat(delta*1000);
if (!amount_msat_sub(&delivered, delivered, excess)) {
if (fail)
*fail = tal_fmt(
ctx, "unable to substract excess");
goto function_fail;
plugin_err(plugin, "Unable to subtract excess %s from %s",
fmt_amount_msat(excess),
fmt_amount_msat(delivered));
}
excess = amount_msat(0);
fp->amount = delivered;