1 //! Various user-configurable channel limits and settings which ChannelManager
4 use ln::channelmanager::{BREAKDOWN_TIMEOUT, MAX_LOCAL_BREAKDOWN_TIMEOUT};
6 /// Top-level config which holds ChannelHandshakeLimits and ChannelConfig.
7 #[derive(Clone, Debug)]
8 pub struct UserConfig {
9 /// Channel config that we propose to our counterparty.
10 pub own_channel_config: ChannelHandshakeConfig,
11 /// Limits applied to our counterparty's proposed channel config settings.
12 pub peer_channel_config_limits: ChannelHandshakeLimits,
13 /// Channel config which affects behavior during channel lifetime.
14 pub channel_options: ChannelConfig,
18 /// Provides sane defaults for most configurations (but with 0 relay fees!)
21 own_channel_config: ChannelHandshakeConfig::new(),
22 peer_channel_config_limits: ChannelHandshakeLimits::new(),
23 channel_options: ChannelConfig::new(),
28 /// Configuration we set when applicable.
29 #[derive(Clone, Debug)]
30 pub struct ChannelHandshakeConfig {
31 /// Confirmations we will wait for before considering the channel locked in.
32 /// Applied only for inbound channels (see ChannelHandshakeLimits::max_minimum_depth for the
33 /// equivalent limit applied to outbound channels).
34 pub minimum_depth: u32,
35 /// Set to the amount of time we require our counterparty to wait to claim their money.
37 /// It's one of the main parameter of our security model. We (or one of our watchtowers) MUST
38 /// be online to check for peer having broadcast a revoked transaction to steal our funds
39 /// at least once every our_to_self_delay blocks.
40 /// Default is BREAKDOWN_TIMEOUT, we enforce it as a minimum at channel opening so you can
41 /// tweak config to ask for more security, not less.
43 /// Meanwhile, asking for a too high delay, we bother peer to freeze funds for nothing in
44 /// case of an honest unilateral channel close, which implicitly decrease the economic value of
46 pub our_to_self_delay: u16,
49 impl ChannelHandshakeConfig {
50 /// Provides sane defaults for `ChannelHandshakeConfig`
51 pub fn new() -> ChannelHandshakeConfig {
52 ChannelHandshakeConfig {
54 our_to_self_delay: BREAKDOWN_TIMEOUT,
59 /// Optional channel limits which are applied during channel creation.
61 /// These limits are only applied to our counterparty's limits, not our own.
63 /// Use 0/<type>::max_value() as appropriate to skip checking.
64 #[derive(Copy, Clone, Debug)]
65 pub struct ChannelHandshakeLimits {
66 /// Minimum allowed satoshis when a channel is funded, this is supplied by the sender and so
67 /// only applies to inbound channels.
68 pub min_funding_satoshis: u64,
69 /// The remote node sets a limit on the minimum size of HTLCs we can send to them. This allows
70 /// you to limit the maximum minimum-size they can require.
71 pub max_htlc_minimum_msat: u64,
72 /// The remote node sets a limit on the maximum value of pending HTLCs to them at any given
73 /// time to limit their funds exposure to HTLCs. This allows you to set a minimum such value.
74 pub min_max_htlc_value_in_flight_msat: u64,
75 /// The remote node will require we keep a certain amount in direct payment to ourselves at all
76 /// time, ensuring that we are able to be punished if we broadcast an old state. This allows to
77 /// you limit the amount which we will have to keep to ourselves (and cannot use for HTLCs).
78 pub max_channel_reserve_satoshis: u64,
79 /// The remote node sets a limit on the maximum number of pending HTLCs to them at any given
80 /// time. This allows you to set a minimum such value.
81 pub min_max_accepted_htlcs: u16,
82 /// Outputs below a certain value will not be added to on-chain transactions. The dust value is
83 /// required to always be higher than this value so this only applies to HTLC outputs (and
84 /// potentially to-self outputs before any payments have been made).
85 /// Thus, HTLCs below this amount plus HTLC transaction fees are not enforceable on-chain.
86 /// This setting allows you to set a minimum dust limit for their commitment transactions,
87 /// reflecting the reality that tiny outputs are not considered standard transactions and will
88 /// not propagate through the Bitcoin network.
89 /// Defaults to 546, or the current dust limit on the Bitcoin network.
90 pub min_dust_limit_satoshis: u64,
91 /// Maximum allowed threshold above which outputs will not be generated in their commitment
93 /// HTLCs below this amount plus HTLC transaction fees are not enforceable on-chain.
94 pub max_dust_limit_satoshis: u64,
95 /// Before a channel is usable the funding transaction will need to be confirmed by at least a
96 /// certain number of blocks, specified by the node which is not the funder (as the funder can
97 /// assume they aren't going to double-spend themselves).
98 /// This config allows you to set a limit on the maximum amount of time to wait. Defaults to
99 /// 144 blocks or roughly one day and only applies to outbound channels.
100 pub max_minimum_depth: u32,
101 /// Set to force the incoming channel to match our announced channel preference in
103 /// Defaults to true to make the default that no announced channels are possible (which is
104 /// appropriate for any nodes which are not online very reliably).
105 pub force_announced_channel_preference: bool,
106 /// Set to the amount of time we're willing to wait to claim money back to us.
108 /// Not checking this value would be a security issue, as our peer would be able to set it to
109 /// max relative lock-time (a year) and we would "lose" money as it would be locked for a long time.
110 /// Default is MAX_LOCAL_BREAKDOWN_TIMEOUT, which we also enforce as a maximum value
111 /// so you can tweak config to reduce the loss of having useless locked funds (if your peer accepts)
112 pub their_to_self_delay: u16
115 impl ChannelHandshakeLimits {
116 /// Provides sane defaults for most configurations.
118 /// Most additional limits are disabled except those with which specify a default in individual
119 /// field documentation. Note that this may result in barely-usable channels, but since they
120 /// are applied mostly only to incoming channels that's not much of a problem.
121 pub fn new() -> Self {
122 ChannelHandshakeLimits {
123 min_funding_satoshis: 0,
124 max_htlc_minimum_msat: <u64>::max_value(),
125 min_max_htlc_value_in_flight_msat: 0,
126 max_channel_reserve_satoshis: <u64>::max_value(),
127 min_max_accepted_htlcs: 0,
128 min_dust_limit_satoshis: 546,
129 max_dust_limit_satoshis: <u64>::max_value(),
130 max_minimum_depth: 144,
131 force_announced_channel_preference: true,
132 their_to_self_delay: MAX_LOCAL_BREAKDOWN_TIMEOUT,
137 /// Options which apply on a per-channel basis and may change at runtime or based on negotiation
138 /// with our counterparty.
139 #[derive(Copy, Clone, Debug)]
140 pub struct ChannelConfig {
141 /// Amount (in millionths of a satoshi) the channel will charge per transferred satoshi.
142 /// This may be allowed to change at runtime in a later update, however doing so must result in
143 /// update messages sent to notify all nodes of our updated relay fee.
144 pub fee_proportional_millionths: u32,
145 /// Set to announce the channel publicly and notify all nodes that they can route via this
148 /// This should only be set to true for nodes which expect to be online reliably.
150 /// As the node which funds a channel picks this value this will only apply for new outbound
151 /// channels unless ChannelHandshakeLimits::force_announced_channel_preferences is set.
153 /// This cannot be changed after the initial channel handshake.
154 pub announced_channel: bool,
155 /// When set, we commit to an upfront shutdown_pubkey at channel open. If our counterparty
156 /// supports it, they will then enforce the mutual-close output to us matches what we provided
157 /// at intialization, preventing us from closing to an alternate pubkey.
159 /// This is set to true by default to provide a slight increase in security, though ultimately
160 /// any attacker who is able to take control of a channel can just as easily send the funds via
161 /// lightning payments, so we never require that our counterparties support this option.
163 /// This cannot be changed after a channel has been initialized.
164 pub commit_upfront_shutdown_pubkey: bool
168 /// Provides sane defaults for most configurations (but with zero relay fees!).
169 pub fn new() -> Self {
171 fee_proportional_millionths: 0,
172 announced_channel: false,
173 commit_upfront_shutdown_pubkey: true,
178 //Add write and readable traits to channelconfig
179 impl_writeable!(ChannelConfig, 8+1+1, {
180 fee_proportional_millionths,
182 commit_upfront_shutdown_pubkey