mirrors/core-lightning
1
0
Fork 0
mirror of https://github.com/ElementsProject/lightning.git synced 2025-01-18 13:25:43 +01:00
Code Issues Projects Releases Wiki Activity

payalgo: Be willing to overpay up to maxfeepercent, for privacy.

Browse Source 
This obscures how far an intermediate hop is from the ultimate
payee, and also obscures slightly the exact payment value.

Fixes: #1089
This commit is contained in:
ZmnSCPxj 2018-03-21 15:19:31 +00:00 committed by Christian Decker
parent bc5fc692d1
commit c1a43a04af
1 changed files with 19 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
lightningd/payalgo.c
View File

@ -5,6 +5,7 @@
#include <ccan/tal/str/str.h> #include <ccan/tal/str/str.h>
#include <ccan/time/time.h> #include <ccan/time/time.h>
#include <common/bolt11.h> #include <common/bolt11.h>
#include <common/pseudorand.h>
#include <common/timeout.h> #include <common/timeout.h>
#include <common/type_to_string.h> #include <common/type_to_string.h>
#include <gossipd/gen_gossip_wire.h> #include <gossipd/gen_gossip_wire.h>
@ -487,6 +488,8 @@ static bool json_pay_try(struct pay *pay)
struct command *cmd = pay->cmd; struct command *cmd = pay->cmd;
struct timeabs now = time_now(); struct timeabs now = time_now();
struct siphash_seed seed; struct siphash_seed seed;
u64 maxoverpayment;
u64 overpayment;
/* If too late anyway, fail now. */ /* If too late anyway, fail now. */
if (time_after(now, pay->expiry)) { if (time_after(now, pay->expiry)) {
@ -513,13 +516,28 @@ static bool json_pay_try(struct pay *pay)
/* Generate random seed */ /* Generate random seed */
randombytes_buf(&seed, sizeof(seed)); randombytes_buf(&seed, sizeof(seed));
/* Generate an overpayment, from fuzz * maxfee. */
/* Now normally the use of double for money is very bad.
* Note however that a later stage will ensure that
* we do not end up paying more than maxfeepercent
* of the msatoshi we intend to pay. */
maxoverpayment = ((double) pay->msatoshi * pay->fuzz * pay->maxfeepercent)
/ 100.0;
if (maxoverpayment > 0) {
/* We will never generate the maximum computed
* overpayment this way. Maybe OK for most
* purposes. */
overpayment = pseudorand(maxoverpayment);
} else
overpayment = 0;
++pay->getroute_tries; ++pay->getroute_tries;
/* FIXME: use b11->routes */ /* FIXME: use b11->routes */
req = towire_gossip_getroute_request(pay->try_parent, req = towire_gossip_getroute_request(pay->try_parent,
&cmd->ld->id, &cmd->ld->id,
&pay->receiver_id, &pay->receiver_id,
pay->msatoshi, pay->msatoshi + overpayment,
pay->riskfactor, pay->riskfactor,
pay->min_final_cltv_expiry, pay->min_final_cltv_expiry,
&pay->fuzz, &pay->fuzz,