core-lightning/doc/lightning-setchannel.7.md

lightning-setchannel -- Command for configuring fees / htlc range advertized for a channel

SYNOPSIS

setchannel id [feebase] [feeppm] [htlcmin] [htlcmax] [enforcedelay] [ignorefeelimits]

DESCRIPTION

The setchannel RPC command sets channel specific routing fees, and htlc_minimum_msat or htlc_maximum_msat as defined in BOLT #7. The channel has to be in normal or awaiting state. This can be checked by listpeers reporting a state of CHANNELD_NORMAL or CHANNELD_AWAITING_LOCKIN for the channel.

These changes (for a public channel) will be broadcast to the rest of the network (though many nodes limit the rate of such changes they will accept: we allow 2 a day, with a few extra occasionally).

id is required and should contain a scid (short channel ID), channel id or peerid (pubkey) of the channel to be modified. If id is set to "all", the updates are applied to all channels in states CHANNELD_NORMAL CHANNELD_AWAITING_LOCKIN or DUALOPEND_AWAITING_LOCKIN. If id is a peerid, all channels with the +peer in those states are changed.

feebase is an optional value in millisatoshi that is added as base fee to any routed payment: if omitted, it is unchanged. It can be a whole number, or a whole number ending in msat or sat, or a number with three decimal places ending in sat, or a number with 1 to 11 decimal places ending in btc.

feeppm is an optional value that is added proportionally per-millionths to any routed payment volume in satoshi. For example, if ppm is 1,000 and 1,000,000 satoshi is being routed through the channel, an proportional fee of 1,000 satoshi is added, resulting in a 0.1% fee.

htlcmin is an optional value that limits how small an HTLC we will forward: if omitted, it is unchanged (the default is no lower limit). It can be a whole number, or a whole number ending in msat or sat, or a number with three decimal places ending in sat, or a number with 1 to 11 decimal places ending in btc. Note that the peer also enforces a minimum for the channel: setting it below that will simply set it to that value with a warning. Also note that htlcmin only applies to forwarded HTLCs: we can still send smaller payments ourselves.

htlcmax is an optional value that limits how large an HTLC we will forward: if omitted, it is unchanged (the default is no effective limit). It can be a whole number, or a whole number ending in msat or sat, or a number with three decimal places ending in sat, or a number with 1 to 11 decimal places ending in btc. Note that htlcmax only applies to forwarded HTLCs: we can still send larger payments ourselves.

enforcedelay is the number of seconds to delay before enforcing the new fees/htlc max (default 600, which is ten minutes). This gives the network a chance to catch up with the new rates and avoids rejecting HTLCs before they do. This only has an effect if rates are increased (we always allow users to overpay fees) or htlcmax is decreased, and only applied to a single rate increase per channel (we don't remember an arbitrary number of prior feerates) and if the node is restarted the updated configuration is enforced immediately.

ignorefeelimits set to True means to allow the peer to set the commitment transaction fees (or closing transaction fees) to any value they want. This is dangerous: they could set an exorbitant fee (so HTLCs are unenforcable), or a tiny fee (so that commitment transactions cannot be relayed), but avoids channel breakage in case of feerate disagreements. (Note: the global ignore_fee_limits setting overrides this).

RETURN VALUE

On success, an object containing channels is returned. It is an array of objects, where each object contains:

• peer_id (pubkey): The node_id of the peer
• channel_id (hex): The channel_id of the channel (always 64 characters)
• fee_base_msat (msat): The resulting feebase (this is the BOLT #7 name)
• fee_proportional_millionths (u32): The resulting feeppm (this is the BOLT #7 name)
• ignore_fee_limits (boolean): If we are now allowing peer to set feerate on commitment transaction without restriction (added v23.08)
• minimum_htlc_out_msat (msat): The resulting htlcmin we will advertize (the BOLT #7 name is htlc_minimum_msat)
• maximum_htlc_out_msat (msat): The resulting htlcmax we will advertize (the BOLT #7 name is htlc_maximum_msat)
• short_channel_id (short_channel_id, optional): the short_channel_id (if locked in)
• the following warnings are possible:
  • warning_htlcmin_too_low: The requested htlcmin was too low for this peer, so we set it to the minimum they will allow
  • warning_htlcmax_too_high: The requested htlcmax was greater than the channel capacity, so we set it to the channel capacity

ERRORS

The following error codes may occur:

• -1: Channel is in incorrect state, i.e. Catchall nonspecific error.
• -32602: JSONRPC2_INVALID_PARAMS, i.e. Given id is not a channel ID or short channel ID.

AUTHOR

Michael Schmoock <michael@schmoock.net> is the author of this feature. Rusty Russell <rusty@rustcorp.com.au> is mainly responsible for the Core Lightning project.

SEE ALSO

lightningd-config(5), lightning-fundchannel(7), lightning-listchannels(7), lightning-listpeers(7)

RESOURCES

Main web site: https://github.com/ElementsProject/lightning