Skip to content

pay: Exempt a fee from the maxfeepercent rule it is still tiny #1765

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
rustyrussell merged 3 commits into from
Jul 30, 2018
Merged

pay: Exempt a fee from the maxfeepercent rule it is still tiny #1765

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
252203d
pay: Exempt a fee from the maxfeepercent rule it is still tiny
cdecker Jul 27, 2018
96881f8
doc: Update the compiled version of doc/lightning-pay.7
cdecker Jul 28, 2018
dddf5ca
json-rpc: Update the help text for `pay` to include exemptfee
cdecker Jul 28, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 3 additions & 3 deletions doc/lightning-pay.7
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,12 +2,12 @@
.\" Title: lightning-pay
.\" Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\" Date: 04/26/2018
.\" Date: 07/28/2018
.\" Manual: \ \&
.\" Source: \ \&
.\" Language: English
.\"
.TH "LIGHTNING\-PAY" "7" "04/26/2018" "\ \&" "\ \&"
.TH "LIGHTNING\-PAY" "7" "07/28/2018" "\ \&" "\ \&"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
Expand All @@ -34,7 +34,7 @@ lightning-pay \- Command for sending a payment to a BOLT11 invoice
\fBpay\fR \fIbolt11\fR [\fImsatoshi\fR] [\fIdescription\fR] [\fIriskfactor\fR] [\fImaxfeepercent\fR] [\fIretry_for\fR] [\fImaxdelay\fR]
.SH "DESCRIPTION"
.sp
The \fBpay\fR RPC command attempts to find a route to the given destination, and send the funds it asks for\&. If the \fIbolt11\fR does not contain an amount, \fImsatoshi\fR is required, otherwise if it is specified it must be \fInull\fR\&. If \fIbolt11\fR contains a description hash (\fIh\fR field) \fIdescription\fR is required, otherwise it is unused\&. The \fIriskfactor\fR is described in detail in lightning\-getroute(7), and defaults to 1\&.0\&. The \fImaxfeepercent\fR limits the money paid in fees, and defaults to 0\&.5\&. The \(oqmaxfeepercent\(cq is a percentage of the amount that is to be paid\&.
The \fBpay\fR RPC command attempts to find a route to the given destination, and send the funds it asks for\&. If the \fIbolt11\fR does not contain an amount, \fImsatoshi\fR is required, otherwise if it is specified it must be \fInull\fR\&. If \fIbolt11\fR contains a description hash (\fIh\fR field) \fIdescription\fR is required, otherwise it is unused\&. The \fIriskfactor\fR is described in detail in lightning\-getroute(7), and defaults to 1\&.0\&. The \fImaxfeepercent\fR limits the money paid in fees, and defaults to 0\&.5\&. The maxfeepercent\*(Aq is a percentage of the amount that is to be paid\&. The `exemptfee option can be used for tiny payments which would be dominated by the fee leveraged by forwarding nodes\&. Setting exemptfee allows the maxfeepercent check to be skipped on fees that are smaller than exemptfee (default: 5000 millsatoshi)\&.
.sp
The \fBpay\fR RPC command will randomize routes slightly, as long as the route achieves the targeted \fImaxfeepercent\fR and \fImaxdelay\fR\&.
.sp
Expand Down
4 changes: 4 additions & 0 deletions doc/lightning-pay.7.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,10 @@ in lightning-getroute(7), and defaults to 1.0.
The 'maxfeepercent' limits the money paid in fees, and defaults to 0.5.
The `maxfeepercent' is a percentage of the amount that is to be
paid.
The `exemptfee` option can be used for tiny payments which would be dominated by
the fee leveraged by forwarding nodes. Setting `exemptfee` allows the
`maxfeepercent` check to be skipped on fees that are smaller than `exemptfee`
(default: 5000 millsatoshi).

The *pay* RPC command will randomize routes slightly, as long as the
route achieves the targeted 'maxfeepercent' and 'maxdelay'.
Expand Down
11 changes: 10 additions & 1 deletion lightningd/payalgo.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -128,6 +128,11 @@ struct pay {

/* Whether we are attempting payment or not. */
bool in_sendpay;

/* Maximum fee that is exempted from the maxfeepercent computation. This
* is mainly useful for tiny transfers for which the leveraged fee would
* be dominated by the forwarding fee. */
u64 exemptfee;
};

static struct routing_failure *
Expand Down Expand Up @@ -435,7 +440,7 @@ static void json_pay_getroute_reply(struct subd *gossip UNUSED,
* That loss will not be representable in double. So, it's Okay to
* cast u64 to double for feepercent calculation. */
feepercent = ((double) fee) * 100.0 / ((double) pay->msatoshi);
fee_too_high = (feepercent > pay->maxfeepercent);
fee_too_high = (fee > pay->exemptfee && feepercent > pay->maxfeepercent);
delay_too_high = (route[0].delay > pay->maxdelay);
/* compare fuzz to range */
if ((fee_too_high || delay_too_high) && pay->fuzz < 0.01) {
Expand Down Expand Up @@ -602,6 +607,7 @@ static void json_pay(struct command *cmd,
char *fail, *b11str, *desc;
unsigned int retryfor;
unsigned int maxdelay;
unsigned int exemptfee;

if (!param(cmd, buffer, params,
p_req("bolt11", json_tok_tok, &bolt11tok),
Expand All @@ -612,6 +618,7 @@ static void json_pay(struct command *cmd,
p_opt_def("retry_for", json_tok_number, &retryfor, 60),
p_opt_def("maxdelay", json_tok_number, &maxdelay,
cmd->ld->config.locktime_max),
p_opt_def("exemptfee", json_tok_number, &exemptfee, 5000),
Copy link
Copy Markdown
Collaborator

@renepickhardt renepickhardt Jul 27, 2018

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

does that also make the argument available as an option in the config file?

Copy link
Copy Markdown
Contributor

@wythe wythe Jul 27, 2018

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No. This only deals with json parameters. config and command line parameters are handled in lightningd/options.c.

NULL))
return;

Expand All @@ -636,6 +643,7 @@ static void json_pay(struct command *cmd,
memset(&pay->expiry, 0, sizeof(pay->expiry));
pay->expiry.ts.tv_sec = b11->timestamp + b11->expiry;
pay->min_final_cltv_expiry = b11->min_final_cltv_expiry;
pay->exemptfee = exemptfee;

if (b11->msatoshi) {
if (msatoshi) {
Expand Down Expand Up @@ -703,6 +711,7 @@ static const struct json_command pay_command = {
"{description} (required if {bolt11} uses description hash), "
"{riskfactor} (default 1.0), "
"{maxfeepercent} (default 0.5) the maximum acceptable fee as a percentage (e.g. 0.5 => 0.5%), "
"{exemptfee} (default 5000 msat) disables the maxfeepercent check for fees below the threshold, "
"{retry_for} (default 60) the integer number of seconds before we stop retrying, and "
"{maxdelay} (default 500) the maximum number of blocks we allow the funds to possibly get locked"
};
Expand Down
6 changes: 3 additions & 3 deletions wallet/invoices.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -65,9 +65,9 @@ bool invoices_create(struct invoices *invoices,
/**
* invoices_find_by_label - Search for an invoice by label
*
* @invoices - the invoice handler.
* @pinvoice - pointer to location to load found invoice in.
* @label - the label to search for.
* @param invoices - the invoice handler.
* @param pinvoice - pointer to location to load found invoice in.
* @param label - the label to search for.
*
* Returns false if no invoice with that label exists.
* Returns true if found.
Expand Down