1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Various user-configurable channel limits and settings which ChannelManager
13 use ln::channelmanager::{BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
15 /// Top-level config which holds ChannelHandshakeLimits and ChannelConfig.
17 /// Default::default() provides sane defaults for most configurations
18 /// (but currently with 0 relay fees!)
19 #[derive(Clone, Debug)]
20 pub struct UserConfig {
21 /// Channel config that we propose to our counterparty.
22 pub own_channel_config: ChannelHandshakeConfig,
23 /// Limits applied to our counterparty's proposed channel config settings.
24 pub peer_channel_config_limits: ChannelHandshakeLimits,
25 /// Channel config which affects behavior during channel lifetime.
26 pub channel_options: ChannelConfig,
29 impl Default for UserConfig {
30 fn default() -> Self {
32 own_channel_config: ChannelHandshakeConfig::default(),
33 peer_channel_config_limits: ChannelHandshakeLimits::default(),
34 channel_options: ChannelConfig::default(),
39 /// Configuration we set when applicable.
41 /// Default::default() provides sane defaults.
42 #[derive(Clone, Debug)]
43 pub struct ChannelHandshakeConfig {
44 /// Confirmations we will wait for before considering the channel locked in.
45 /// Applied only for inbound channels (see ChannelHandshakeLimits::max_minimum_depth for the
46 /// equivalent limit applied to outbound channels).
49 pub minimum_depth: u32,
50 /// Set to the amount of time we require our counterparty to wait to claim their money.
52 /// It's one of the main parameter of our security model. We (or one of our watchtowers) MUST
53 /// be online to check for peer having broadcast a revoked transaction to steal our funds
54 /// at least once every our_to_self_delay blocks.
56 /// Meanwhile, asking for a too high delay, we bother peer to freeze funds for nothing in
57 /// case of an honest unilateral channel close, which implicitly decrease the economic value of
60 /// Default value: BREAKDOWN_TIMEOUT (currently 144), we enforce it as a minimum at channel
61 /// opening so you can tweak config to ask for more security, not less.
62 pub our_to_self_delay: u16,
63 /// Set to the smallest value HTLC we will accept to process.
65 /// This value is sent to our counterparty on channel-open and we close the channel any time
66 /// our counterparty misbehaves by sending us an HTLC with a value smaller than this.
68 /// Default value: 1. If the value is less than 1, it is ignored and set to 1, as is required
70 pub our_htlc_minimum_msat: u64,
73 impl Default for ChannelHandshakeConfig {
74 fn default() -> ChannelHandshakeConfig {
75 ChannelHandshakeConfig {
77 our_to_self_delay: BREAKDOWN_TIMEOUT,
78 our_htlc_minimum_msat: 1,
83 /// Optional channel limits which are applied during channel creation.
85 /// These limits are only applied to our counterparty's limits, not our own.
87 /// Use 0/<type>::max_value() as appropriate to skip checking.
89 /// Provides sane defaults for most configurations.
91 /// Most additional limits are disabled except those with which specify a default in individual
92 /// field documentation. Note that this may result in barely-usable channels, but since they
93 /// are applied mostly only to incoming channels that's not much of a problem.
94 #[derive(Copy, Clone, Debug)]
95 pub struct ChannelHandshakeLimits {
96 /// Minimum allowed satoshis when a channel is funded, this is supplied by the sender and so
97 /// only applies to inbound channels.
100 pub min_funding_satoshis: u64,
101 /// The remote node sets a limit on the minimum size of HTLCs we can send to them. This allows
102 /// you to limit the maximum minimum-size they can require.
104 /// Default value: u64::max_value.
105 pub max_htlc_minimum_msat: u64,
106 /// The remote node sets a limit on the maximum value of pending HTLCs to them at any given
107 /// time to limit their funds exposure to HTLCs. This allows you to set a minimum such value.
109 /// Default value: 0.
110 pub min_max_htlc_value_in_flight_msat: u64,
111 /// The remote node will require we keep a certain amount in direct payment to ourselves at all
112 /// time, ensuring that we are able to be punished if we broadcast an old state. This allows to
113 /// you limit the amount which we will have to keep to ourselves (and cannot use for HTLCs).
115 /// Default value: u64::max_value.
116 pub max_channel_reserve_satoshis: u64,
117 /// The remote node sets a limit on the maximum number of pending HTLCs to them at any given
118 /// time. This allows you to set a minimum such value.
120 /// Default value: 0.
121 pub min_max_accepted_htlcs: u16,
122 /// Outputs below a certain value will not be added to on-chain transactions. The dust value is
123 /// required to always be higher than this value so this only applies to HTLC outputs (and
124 /// potentially to-self outputs before any payments have been made).
125 /// Thus, HTLCs below this amount plus HTLC transaction fees are not enforceable on-chain.
126 /// This setting allows you to set a minimum dust limit for their commitment transactions,
127 /// reflecting the reality that tiny outputs are not considered standard transactions and will
128 /// not propagate through the Bitcoin network.
130 /// Default value: 546, the current dust limit on the Bitcoin network.
131 pub min_dust_limit_satoshis: u64,
132 /// Maximum allowed threshold above which outputs will not be generated in their commitment
134 /// HTLCs below this amount plus HTLC transaction fees are not enforceable on-chain.
136 /// Default value: u64::max_value.
137 pub max_dust_limit_satoshis: u64,
138 /// Before a channel is usable the funding transaction will need to be confirmed by at least a
139 /// certain number of blocks, specified by the node which is not the funder (as the funder can
140 /// assume they aren't going to double-spend themselves).
141 /// This config allows you to set a limit on the maximum amount of time to wait.
143 /// Default value: 144, or roughly one day and only applies to outbound channels.
144 pub max_minimum_depth: u32,
145 /// Set to force the incoming channel to match our announced channel preference in
148 /// Default value: true, to make the default that no announced channels are possible (which is
149 /// appropriate for any nodes which are not online very reliably).
150 pub force_announced_channel_preference: bool,
151 /// Set to the amount of time we're willing to wait to claim money back to us.
153 /// Not checking this value would be a security issue, as our peer would be able to set it to
154 /// max relative lock-time (a year) and we would "lose" money as it would be locked for a long time.
156 /// Default value: MAX_LOCAL_BREAKDOWN_TIMEOUT (1008), which we also enforce as a maximum value
157 /// so you can tweak config to reduce the loss of having useless locked funds (if your peer accepts)
158 pub their_to_self_delay: u16
161 impl Default for ChannelHandshakeLimits {
162 fn default() -> Self {
163 ChannelHandshakeLimits {
164 min_funding_satoshis: 0,
165 max_htlc_minimum_msat: <u64>::max_value(),
166 min_max_htlc_value_in_flight_msat: 0,
167 max_channel_reserve_satoshis: <u64>::max_value(),
168 min_max_accepted_htlcs: 0,
169 min_dust_limit_satoshis: 546,
170 max_dust_limit_satoshis: <u64>::max_value(),
171 max_minimum_depth: 144,
172 force_announced_channel_preference: true,
173 their_to_self_delay: MAX_LOCAL_BREAKDOWN_TIMEOUT,
178 /// Options which apply on a per-channel basis and may change at runtime or based on negotiation
179 /// with our counterparty.
180 #[derive(Copy, Clone, Debug)]
181 pub struct ChannelConfig {
182 /// Amount (in millionths of a satoshi) the channel will charge per transferred satoshi.
183 /// This may be allowed to change at runtime in a later update, however doing so must result in
184 /// update messages sent to notify all nodes of our updated relay fee.
186 /// Default value: 0.
187 pub fee_proportional_millionths: u32,
188 /// Set to announce the channel publicly and notify all nodes that they can route via this
191 /// This should only be set to true for nodes which expect to be online reliably.
193 /// As the node which funds a channel picks this value this will only apply for new outbound
194 /// channels unless ChannelHandshakeLimits::force_announced_channel_preferences is set.
196 /// This cannot be changed after the initial channel handshake.
198 /// Default value: false.
199 pub announced_channel: bool,
200 /// When set, we commit to an upfront shutdown_pubkey at channel open. If our counterparty
201 /// supports it, they will then enforce the mutual-close output to us matches what we provided
202 /// at intialization, preventing us from closing to an alternate pubkey.
204 /// This is set to true by default to provide a slight increase in security, though ultimately
205 /// any attacker who is able to take control of a channel can just as easily send the funds via
206 /// lightning payments, so we never require that our counterparties support this option.
208 /// This cannot be changed after a channel has been initialized.
210 /// Default value: true.
211 pub commit_upfront_shutdown_pubkey: bool
214 impl Default for ChannelConfig {
215 /// Provides sane defaults for most configurations (but with zero relay fees!).
216 fn default() -> Self {
218 fee_proportional_millionths: 0,
219 announced_channel: false,
220 commit_upfront_shutdown_pubkey: true,
225 //Add write and readable traits to channelconfig
226 impl_writeable!(ChannelConfig, 8+1+1, {
227 fee_proportional_millionths,
229 commit_upfront_shutdown_pubkey