Merge pull request #2691 from wpaulino/refactor-channel-state
[rust-lightning] / lightning / src / ln / channel.rs
index 117986acf1010cc2e08c2f210be05ff97aad0ab5..8d6144fc25f9c3ed4a123c77406cc43b6ca4924f 100644 (file)
@@ -261,76 +261,293 @@ enum HTLCUpdateAwaitingACK {
        },
 }
 
-/// There are a few "states" and then a number of flags which can be applied:
-/// We first move through init with `OurInitSent` -> `TheirInitSent` -> `FundingCreated` -> `FundingSent`.
-/// `TheirChannelReady` and `OurChannelReady` then get set on `FundingSent`, and when both are set we
-/// move on to `ChannelReady`.
-/// Note that `PeerDisconnected` can be set on both `ChannelReady` and `FundingSent`.
-/// `ChannelReady` can then get all remaining flags set on it, until we finish shutdown, then we
-/// move on to `ShutdownComplete`, at which point most calls into this channel are disallowed.
+macro_rules! define_state_flags {
+       ($flag_type_doc: expr, $flag_type: ident, [$(($flag_doc: expr, $flag: ident, $value: expr)),+], $extra_flags: expr) => {
+               #[doc = $flag_type_doc]
+               #[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq)]
+               struct $flag_type(u32);
+
+               impl $flag_type {
+                       $(
+                               #[doc = $flag_doc]
+                               const $flag: $flag_type = $flag_type($value);
+                       )*
+
+                       /// All flags that apply to the specified [`ChannelState`] variant.
+                       #[allow(unused)]
+                       const ALL: $flag_type = Self($(Self::$flag.0 | )* $extra_flags);
+
+                       #[allow(unused)]
+                       fn new() -> Self { Self(0) }
+
+                       #[allow(unused)]
+                       fn from_u32(flags: u32) -> Result<Self, ()> {
+                               if flags & !Self::ALL.0 != 0 {
+                                       Err(())
+                               } else {
+                                       Ok($flag_type(flags))
+                               }
+                       }
+
+                       #[allow(unused)]
+                       fn is_empty(&self) -> bool { self.0 == 0 }
+
+                       #[allow(unused)]
+                       fn is_set(&self, flag: Self) -> bool { *self & flag == flag }
+               }
+
+               impl core::ops::Not for $flag_type {
+                       type Output = Self;
+                       fn not(self) -> Self::Output { Self(!self.0) }
+               }
+               impl core::ops::BitOr for $flag_type {
+                       type Output = Self;
+                       fn bitor(self, rhs: Self) -> Self::Output { Self(self.0 | rhs.0) }
+               }
+               impl core::ops::BitOrAssign for $flag_type {
+                       fn bitor_assign(&mut self, rhs: Self) { self.0 |= rhs.0; }
+               }
+               impl core::ops::BitAnd for $flag_type {
+                       type Output = Self;
+                       fn bitand(self, rhs: Self) -> Self::Output { Self(self.0 & rhs.0) }
+               }
+               impl core::ops::BitAndAssign for $flag_type {
+                       fn bitand_assign(&mut self, rhs: Self) { self.0 &= rhs.0; }
+               }
+       };
+       ($flag_type_doc: expr, $flag_type: ident, $flags: tt) => {
+               define_state_flags!($flag_type_doc, $flag_type, $flags, 0);
+       };
+       ($flag_type_doc: expr, FUNDED_STATE, $flag_type: ident, $flags: tt) => {
+               define_state_flags!($flag_type_doc, $flag_type, $flags, FundedStateFlags::ALL.0);
+               impl core::ops::BitOr<FundedStateFlags> for $flag_type {
+                       type Output = Self;
+                       fn bitor(self, rhs: FundedStateFlags) -> Self::Output { Self(self.0 | rhs.0) }
+               }
+               impl core::ops::BitOrAssign<FundedStateFlags> for $flag_type {
+                       fn bitor_assign(&mut self, rhs: FundedStateFlags) { self.0 |= rhs.0; }
+               }
+               impl core::ops::BitAnd<FundedStateFlags> for $flag_type {
+                       type Output = Self;
+                       fn bitand(self, rhs: FundedStateFlags) -> Self::Output { Self(self.0 & rhs.0) }
+               }
+               impl core::ops::BitAndAssign<FundedStateFlags> for $flag_type {
+                       fn bitand_assign(&mut self, rhs: FundedStateFlags) { self.0 &= rhs.0; }
+               }
+               impl PartialEq<FundedStateFlags> for $flag_type {
+                       fn eq(&self, other: &FundedStateFlags) -> bool { self.0 == other.0 }
+               }
+               impl From<FundedStateFlags> for $flag_type {
+                       fn from(flags: FundedStateFlags) -> Self { Self(flags.0) }
+               }
+       };
+}
+
+/// We declare all the states/flags here together to help determine which bits are still available
+/// to choose.
+mod state_flags {
+       pub const OUR_INIT_SENT: u32 = 1 << 0;
+       pub const THEIR_INIT_SENT: u32 = 1 << 1;
+       pub const FUNDING_NEGOTIATED: u32 = 1 << 2;
+       pub const AWAITING_CHANNEL_READY: u32 = 1 << 3;
+       pub const THEIR_CHANNEL_READY: u32 = 1 << 4;
+       pub const OUR_CHANNEL_READY: u32 = 1 << 5;
+       pub const CHANNEL_READY: u32 = 1 << 6;
+       pub const PEER_DISCONNECTED: u32 = 1 << 7;
+       pub const MONITOR_UPDATE_IN_PROGRESS: u32 = 1 << 8;
+       pub const AWAITING_REMOTE_REVOKE: u32 = 1 << 9;
+       pub const REMOTE_SHUTDOWN_SENT: u32 = 1 << 10;
+       pub const LOCAL_SHUTDOWN_SENT: u32 = 1 << 11;
+       pub const SHUTDOWN_COMPLETE: u32 = 1 << 12;
+       pub const WAITING_FOR_BATCH: u32 = 1 << 13;
+}
+
+define_state_flags!(
+       "Flags that apply to all [`ChannelState`] variants in which the channel is funded.",
+       FundedStateFlags, [
+               ("Indicates the remote side is considered \"disconnected\" and no updates are allowed \
+                       until after we've done a `channel_reestablish` dance.", PEER_DISCONNECTED, state_flags::PEER_DISCONNECTED),
+               ("Indicates the user has told us a `ChannelMonitor` update is pending async persistence \
+                       somewhere and we should pause sending any outbound messages until they've managed to \
+                       complete it.", MONITOR_UPDATE_IN_PROGRESS, state_flags::MONITOR_UPDATE_IN_PROGRESS),
+               ("Indicates we received a `shutdown` message from the remote end. If set, they may not add \
+                       any new HTLCs to the channel, and we are expected to respond with our own `shutdown` \
+                       message when possible.", REMOTE_SHUTDOWN_SENT, state_flags::REMOTE_SHUTDOWN_SENT),
+               ("Indicates we sent a `shutdown` message. At this point, we may not add any new HTLCs to \
+                       the channel.", LOCAL_SHUTDOWN_SENT, state_flags::LOCAL_SHUTDOWN_SENT)
+       ]
+);
+
+define_state_flags!(
+       "Flags that only apply to [`ChannelState::NegotiatingFunding`].",
+       NegotiatingFundingFlags, [
+               ("Indicates we have (or are prepared to) send our `open_channel`/`accept_channel` message.",
+                       OUR_INIT_SENT, state_flags::OUR_INIT_SENT),
+               ("Indicates we have received their `open_channel`/`accept_channel` message.",
+                       THEIR_INIT_SENT, state_flags::THEIR_INIT_SENT)
+       ]
+);
+
+define_state_flags!(
+       "Flags that only apply to [`ChannelState::AwaitingChannelReady`].",
+       FUNDED_STATE, AwaitingChannelReadyFlags, [
+               ("Indicates they sent us a `channel_ready` message. Once both `THEIR_CHANNEL_READY` and \
+                       `OUR_CHANNEL_READY` are set, our state moves on to `ChannelReady`.",
+                       THEIR_CHANNEL_READY, state_flags::THEIR_CHANNEL_READY),
+               ("Indicates we sent them a `channel_ready` message. Once both `THEIR_CHANNEL_READY` and \
+                       `OUR_CHANNEL_READY` are set, our state moves on to `ChannelReady`.",
+                       OUR_CHANNEL_READY, state_flags::OUR_CHANNEL_READY),
+               ("Indicates the channel was funded in a batch and the broadcast of the funding transaction \
+                       is being held until all channels in the batch have received `funding_signed` and have \
+                       their monitors persisted.", WAITING_FOR_BATCH, state_flags::WAITING_FOR_BATCH)
+       ]
+);
+
+define_state_flags!(
+       "Flags that only apply to [`ChannelState::ChannelReady`].",
+       FUNDED_STATE, ChannelReadyFlags, [
+               ("Indicates that we have sent a `commitment_signed` but are awaiting the responding \
+                       `revoke_and_ack` message. During this period, we can't generate new `commitment_signed` \
+                       messages as we'd be unable to determine which HTLCs they included in their `revoke_and_ack` \
+                       implicit ACK, so instead we have to hold them away temporarily to be sent later.",
+                       AWAITING_REMOTE_REVOKE, state_flags::AWAITING_REMOTE_REVOKE)
+       ]
+);
+
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq)]
 enum ChannelState {
-       /// Implies we have (or are prepared to) send our open_channel/accept_channel message
-       OurInitSent = 1 << 0,
-       /// Implies we have received their `open_channel`/`accept_channel` message
-       TheirInitSent = 1 << 1,
-       /// We have sent `funding_created` and are awaiting a `funding_signed` to advance to `FundingSent`.
-       /// Note that this is nonsense for an inbound channel as we immediately generate `funding_signed`
-       /// upon receipt of `funding_created`, so simply skip this state.
-       FundingCreated = 4,
-       /// Set when we have received/sent `funding_created` and `funding_signed` and are thus now waiting
-       /// on the funding transaction to confirm. The `ChannelReady` flags are set to indicate when we
-       /// and our counterparty consider the funding transaction confirmed.
-       FundingSent = 8,
-       /// Flag which can be set on `FundingSent` to indicate they sent us a `channel_ready` message.
-       /// Once both `TheirChannelReady` and `OurChannelReady` are set, state moves on to `ChannelReady`.
-       TheirChannelReady = 1 << 4,
-       /// Flag which can be set on `FundingSent` to indicate we sent them a `channel_ready` message.
-       /// Once both `TheirChannelReady` and `OurChannelReady` are set, state moves on to `ChannelReady`.
-       OurChannelReady = 1 << 5,
-       ChannelReady = 64,
-       /// Flag which is set on `ChannelReady` and `FundingSent` indicating remote side is considered
-       /// "disconnected" and no updates are allowed until after we've done a `channel_reestablish`
-       /// dance.
-       PeerDisconnected = 1 << 7,
-       /// Flag which is set on `ChannelReady`, FundingCreated, and `FundingSent` indicating the user has
-       /// told us a `ChannelMonitor` update is pending async persistence somewhere and we should pause
-       /// sending any outbound messages until they've managed to finish.
-       MonitorUpdateInProgress = 1 << 8,
-       /// Flag which implies that we have sent a commitment_signed but are awaiting the responding
-       /// revoke_and_ack message. During this time period, we can't generate new commitment_signed
-       /// messages as then we will be unable to determine which HTLCs they included in their
-       /// revoke_and_ack implicit ACK, so instead we have to hold them away temporarily to be sent
-       /// later.
-       /// Flag is set on `ChannelReady`.
-       AwaitingRemoteRevoke = 1 << 9,
-       /// Flag which is set on `ChannelReady` or `FundingSent` after receiving a shutdown message from
-       /// the remote end. If set, they may not add any new HTLCs to the channel, and we are expected
-       /// to respond with our own shutdown message when possible.
-       RemoteShutdownSent = 1 << 10,
-       /// Flag which is set on `ChannelReady` or `FundingSent` after sending a shutdown message. At this
-       /// point, we may not add any new HTLCs to the channel.
-       LocalShutdownSent = 1 << 11,
-       /// We've successfully negotiated a closing_signed dance. At this point ChannelManager is about
-       /// to drop us, but we store this anyway.
-       ShutdownComplete = 4096,
-       /// Flag which is set on `FundingSent` to indicate this channel is funded in a batch and the
-       /// broadcasting of the funding transaction is being held until all channels in the batch
-       /// have received funding_signed and have their monitors persisted.
-       WaitingForBatch = 1 << 13,
+       /// We are negotiating the parameters required for the channel prior to funding it.
+       NegotiatingFunding(NegotiatingFundingFlags),
+       /// We have sent `funding_created` and are awaiting a `funding_signed` to advance to
+       /// `AwaitingChannelReady`. Note that this is nonsense for an inbound channel as we immediately generate
+       /// `funding_signed` upon receipt of `funding_created`, so simply skip this state.
+       FundingNegotiated,
+       /// We've received/sent `funding_created` and `funding_signed` and are thus now waiting on the
+       /// funding transaction to confirm.
+       AwaitingChannelReady(AwaitingChannelReadyFlags),
+       /// Both we and our counterparty consider the funding transaction confirmed and the channel is
+       /// now operational.
+       ChannelReady(ChannelReadyFlags),
+       /// We've successfully negotiated a `closing_signed` dance. At this point, the `ChannelManager`
+       /// is about to drop us, but we store this anyway.
+       ShutdownComplete,
+}
+
+macro_rules! impl_state_flag {
+       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, [$($state: ident),+]) => {
+               #[allow(unused)]
+               fn $get(&self) -> bool {
+                       match self {
+                               $(
+                                       ChannelState::$state(flags) => flags.is_set($state_flag.into()),
+                               )*
+                               _ => false,
+                       }
+               }
+               #[allow(unused)]
+               fn $set(&mut self) {
+                       match self {
+                               $(
+                                       ChannelState::$state(flags) => *flags |= $state_flag,
+                               )*
+                               _ => debug_assert!(false, "Attempted to set flag on unexpected ChannelState"),
+                       }
+               }
+               #[allow(unused)]
+               fn $clear(&mut self) {
+                       match self {
+                               $(
+                                       ChannelState::$state(flags) => *flags &= !($state_flag),
+                               )*
+                               _ => debug_assert!(false, "Attempted to clear flag on unexpected ChannelState"),
+                       }
+               }
+       };
+       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, FUNDED_STATES) => {
+               impl_state_flag!($get, $set, $clear, $state_flag, [AwaitingChannelReady, ChannelReady]);
+       };
+       ($get: ident, $set: ident, $clear: ident, $state_flag: expr, $state: ident) => {
+               impl_state_flag!($get, $set, $clear, $state_flag, [$state]);
+       };
+}
+
+impl ChannelState {
+       fn from_u32(state: u32) -> Result<Self, ()> {
+               match state {
+                       state_flags::FUNDING_NEGOTIATED => Ok(ChannelState::FundingNegotiated),
+                       state_flags::SHUTDOWN_COMPLETE => Ok(ChannelState::ShutdownComplete),
+                       val => {
+                               if val & state_flags::AWAITING_CHANNEL_READY == state_flags::AWAITING_CHANNEL_READY {
+                                       AwaitingChannelReadyFlags::from_u32(val & !state_flags::AWAITING_CHANNEL_READY)
+                                               .map(|flags| ChannelState::AwaitingChannelReady(flags))
+                               } else if val & state_flags::CHANNEL_READY == state_flags::CHANNEL_READY {
+                                       ChannelReadyFlags::from_u32(val & !state_flags::CHANNEL_READY)
+                                               .map(|flags| ChannelState::ChannelReady(flags))
+                               } else if let Ok(flags) = NegotiatingFundingFlags::from_u32(val) {
+                                       Ok(ChannelState::NegotiatingFunding(flags))
+                               } else {
+                                       Err(())
+                               }
+                       },
+               }
+       }
+
+       fn to_u32(&self) -> u32 {
+               match self {
+                       ChannelState::NegotiatingFunding(flags) => flags.0,
+                       ChannelState::FundingNegotiated => state_flags::FUNDING_NEGOTIATED,
+                       ChannelState::AwaitingChannelReady(flags) => state_flags::AWAITING_CHANNEL_READY | flags.0,
+                       ChannelState::ChannelReady(flags) => state_flags::CHANNEL_READY | flags.0,
+                       ChannelState::ShutdownComplete => state_flags::SHUTDOWN_COMPLETE,
+               }
+       }
+
+       fn is_pre_funded_state(&self) -> bool {
+               matches!(self, ChannelState::NegotiatingFunding(_)|ChannelState::FundingNegotiated)
+       }
+
+       fn is_both_sides_shutdown(&self) -> bool {
+               self.is_local_shutdown_sent() && self.is_remote_shutdown_sent()
+       }
+
+       fn with_funded_state_flags_mask(&self) -> FundedStateFlags {
+               match self {
+                       ChannelState::AwaitingChannelReady(flags) => FundedStateFlags((*flags & FundedStateFlags::ALL).0),
+                       ChannelState::ChannelReady(flags) => FundedStateFlags((*flags & FundedStateFlags::ALL).0),
+                       _ => FundedStateFlags::new(),
+               }
+       }
+
+       fn should_force_holding_cell(&self) -> bool {
+               match self {
+                       ChannelState::ChannelReady(flags) =>
+                               flags.is_set(ChannelReadyFlags::AWAITING_REMOTE_REVOKE) ||
+                                       flags.is_set(FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS.into()) ||
+                                       flags.is_set(FundedStateFlags::PEER_DISCONNECTED.into()),
+                       _ => {
+                               debug_assert!(false, "The holding cell is only valid within ChannelReady");
+                               false
+                       },
+               }
+       }
+
+       impl_state_flag!(is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected,
+               FundedStateFlags::PEER_DISCONNECTED, FUNDED_STATES);
+       impl_state_flag!(is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress,
+               FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS, FUNDED_STATES);
+       impl_state_flag!(is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent,
+               FundedStateFlags::LOCAL_SHUTDOWN_SENT, FUNDED_STATES);
+       impl_state_flag!(is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent,
+               FundedStateFlags::REMOTE_SHUTDOWN_SENT, FUNDED_STATES);
+       impl_state_flag!(is_our_channel_ready, set_our_channel_ready, clear_our_channel_ready,
+               AwaitingChannelReadyFlags::OUR_CHANNEL_READY, AwaitingChannelReady);
+       impl_state_flag!(is_their_channel_ready, set_their_channel_ready, clear_their_channel_ready,
+               AwaitingChannelReadyFlags::THEIR_CHANNEL_READY, AwaitingChannelReady);
+       impl_state_flag!(is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch,
+               AwaitingChannelReadyFlags::WAITING_FOR_BATCH, AwaitingChannelReady);
+       impl_state_flag!(is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke,
+               ChannelReadyFlags::AWAITING_REMOTE_REVOKE, ChannelReady);
 }
-const BOTH_SIDES_SHUTDOWN_MASK: u32 =
-       ChannelState::LocalShutdownSent as u32 |
-       ChannelState::RemoteShutdownSent as u32;
-const MULTI_STATE_FLAGS: u32 =
-       BOTH_SIDES_SHUTDOWN_MASK |
-       ChannelState::PeerDisconnected as u32 |
-       ChannelState::MonitorUpdateInProgress as u32;
-const STATE_FLAGS: u32 =
-       MULTI_STATE_FLAGS |
-       ChannelState::TheirChannelReady as u32 |
-       ChannelState::OurChannelReady as u32 |
-       ChannelState::AwaitingRemoteRevoke as u32 |
-       ChannelState::WaitingForBatch as u32;
 
 pub const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
 
@@ -743,7 +960,7 @@ pub(super) struct ChannelContext<SP: Deref> where SP::Target: SignerProvider {
        /// The temporary channel ID used during channel setup. Value kept even after transitioning to a final channel ID.
        /// Will be `None` for channels created prior to 0.0.115.
        temporary_channel_id: Option<ChannelId>,
-       channel_state: u32,
+       channel_state: ChannelState,
 
        // When we reach max(6 blocks, minimum_depth), we need to send an AnnouncementSigs message to
        // our peer. However, we want to make sure they received it, or else rebroadcast it when we
@@ -1040,49 +1257,55 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
        /// Returns true if we've ever received a message from the remote end for this Channel
        pub fn have_received_message(&self) -> bool {
-               self.channel_state & !STATE_FLAGS > (ChannelState::OurInitSent as u32)
+               self.channel_state > ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT)
        }
 
        /// Returns true if this channel is fully established and not known to be closing.
        /// Allowed in any state (including after shutdown)
        pub fn is_usable(&self) -> bool {
-               let mask = ChannelState::ChannelReady as u32 | BOTH_SIDES_SHUTDOWN_MASK;
-               (self.channel_state & mask) == (ChannelState::ChannelReady as u32) && !self.monitor_pending_channel_ready
+               matches!(self.channel_state, ChannelState::ChannelReady(_)) &&
+                       !self.channel_state.is_local_shutdown_sent() &&
+                       !self.channel_state.is_remote_shutdown_sent() &&
+                       !self.monitor_pending_channel_ready
        }
 
        /// shutdown state returns the state of the channel in its various stages of shutdown
        pub fn shutdown_state(&self) -> ChannelShutdownState {
-               if self.channel_state & (ChannelState::ShutdownComplete as u32) != 0 {
-                       return ChannelShutdownState::ShutdownComplete;
-               }
-               if self.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 &&  self.channel_state & (ChannelState::RemoteShutdownSent as u32) == 0 {
-                       return ChannelShutdownState::ShutdownInitiated;
-               }
-               if (self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != 0) && !self.closing_negotiation_ready() {
-                       return ChannelShutdownState::ResolvingHTLCs;
-               }
-               if (self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != 0) && self.closing_negotiation_ready() {
-                       return ChannelShutdownState::NegotiatingClosingFee;
+               match self.channel_state {
+                       ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_) =>
+                               if self.channel_state.is_local_shutdown_sent() && !self.channel_state.is_remote_shutdown_sent() {
+                                       ChannelShutdownState::ShutdownInitiated
+                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && !self.closing_negotiation_ready() {
+                                       ChannelShutdownState::ResolvingHTLCs
+                               } else if (self.channel_state.is_local_shutdown_sent() || self.channel_state.is_remote_shutdown_sent()) && self.closing_negotiation_ready() {
+                                       ChannelShutdownState::NegotiatingClosingFee
+                               } else {
+                                       ChannelShutdownState::NotShuttingDown
+                               },
+                       ChannelState::ShutdownComplete => ChannelShutdownState::ShutdownComplete,
+                       _ => ChannelShutdownState::NotShuttingDown,
                }
-               return ChannelShutdownState::NotShuttingDown;
        }
 
        fn closing_negotiation_ready(&self) -> bool {
+               let is_ready_to_close = match self.channel_state {
+                       ChannelState::AwaitingChannelReady(flags) =>
+                               flags & FundedStateFlags::ALL == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
+                       ChannelState::ChannelReady(flags) =>
+                               flags == FundedStateFlags::LOCAL_SHUTDOWN_SENT | FundedStateFlags::REMOTE_SHUTDOWN_SENT,
+                       _ => false,
+               };
                self.pending_inbound_htlcs.is_empty() &&
-               self.pending_outbound_htlcs.is_empty() &&
-               self.pending_update_fee.is_none() &&
-               self.channel_state &
-               (BOTH_SIDES_SHUTDOWN_MASK |
-                       ChannelState::AwaitingRemoteRevoke as u32 |
-                       ChannelState::PeerDisconnected as u32 |
-                       ChannelState::MonitorUpdateInProgress as u32) == BOTH_SIDES_SHUTDOWN_MASK
+                       self.pending_outbound_htlcs.is_empty() &&
+                       self.pending_update_fee.is_none() &&
+                       is_ready_to_close
        }
 
        /// Returns true if this channel is currently available for use. This is a superset of
        /// is_usable() and considers things like the channel being temporarily disabled.
        /// Allowed in any state (including after shutdown)
        pub fn is_live(&self) -> bool {
-               self.is_usable() && (self.channel_state & (ChannelState::PeerDisconnected as u32) == 0)
+               self.is_usable() && !self.channel_state.is_peer_disconnected()
        }
 
        // Public utilities:
@@ -1334,8 +1557,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
        /// Returns true if funding_signed was sent/received and the
        /// funding transaction has been broadcast if necessary.
        pub fn is_funding_broadcast(&self) -> bool {
-               self.channel_state & !STATE_FLAGS >= ChannelState::FundingSent as u32 &&
-                       self.channel_state & ChannelState::WaitingForBatch as u32 == 0
+               !self.channel_state.is_pre_funded_state() &&
+                       !matches!(self.channel_state, ChannelState::AwaitingChannelReady(flags) if flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH))
        }
 
        /// Transaction nomenclature is somewhat confusing here as there are many different cases - a
@@ -2091,11 +2314,14 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
 
        fn if_unbroadcasted_funding<F, O>(&self, f: F) -> Option<O>
                where F: Fn() -> Option<O> {
-               if self.channel_state & ChannelState::FundingCreated as u32 != 0 ||
-                  self.channel_state & ChannelState::WaitingForBatch as u32 != 0 {
-                       f()
-               } else {
-                       None
+               match self.channel_state {
+                       ChannelState::FundingNegotiated => f(),
+                       ChannelState::AwaitingChannelReady(flags) => if flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH) {
+                               f()
+                       } else {
+                               None
+                       },
+                       _ => None,
                }
        }
 
@@ -2134,7 +2360,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                // called during initialization prior to the chain_monitor in the encompassing ChannelManager
                // being fully configured in some cases. Thus, its likely any monitor events we generate will
                // be delayed in being processed! See the docs for `ChannelManagerReadArgs` for more.
-               assert!(self.channel_state != ChannelState::ShutdownComplete as u32);
+               assert!(!matches!(self.channel_state, ChannelState::ShutdownComplete));
 
                // We go ahead and "free" any holding cell HTLCs or HTLCs we haven't yet committed to and
                // return them to fail the payment.
@@ -2149,14 +2375,18 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        }
                }
                let monitor_update = if let Some(funding_txo) = self.get_funding_txo() {
-                       // If we haven't yet exchanged funding signatures (ie channel_state < FundingSent),
+                       // If we haven't yet exchanged funding signatures (ie channel_state < AwaitingChannelReady),
                        // returning a channel monitor update here would imply a channel monitor update before
                        // we even registered the channel monitor to begin with, which is invalid.
                        // Thus, if we aren't actually at a point where we could conceivably broadcast the
                        // funding transaction, don't return a funding txo (which prevents providing the
                        // monitor update to the user, even if we return one).
                        // See test_duplicate_chan_id and test_pre_lockin_no_chan_closed_update for more.
-                       if self.channel_state & (ChannelState::FundingSent as u32 | ChannelState::ChannelReady as u32 | ChannelState::ShutdownComplete as u32) != 0 {
+                       let generate_monitor_update = match self.channel_state {
+                               ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_)|ChannelState::ShutdownComplete => true,
+                               _ => false,
+                       };
+                       if generate_monitor_update {
                                self.latest_monitor_update_id = CLOSED_CHANNEL_UPDATE_ID;
                                Some((self.get_counterparty_node_id(), funding_txo, ChannelMonitorUpdate {
                                        update_id: self.latest_monitor_update_id,
@@ -2166,7 +2396,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                } else { None };
                let unbroadcasted_batch_funding_txid = self.unbroadcasted_batch_funding_txid();
 
-               self.channel_state = ChannelState::ShutdownComplete as u32;
+               self.channel_state = ChannelState::ShutdownComplete;
                self.update_time_counter += 1;
                ShutdownResult {
                        monitor_update,
@@ -2437,7 +2667,7 @@ impl<SP: Deref> Channel<SP> where
        where L::Target: Logger {
                // Assert that we'll add the HTLC claim to the holding cell in `get_update_fulfill_htlc`
                // (see equivalent if condition there).
-               assert!(self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32) != 0);
+               assert!(self.context.channel_state.should_force_holding_cell());
                let mon_update_id = self.context.latest_monitor_update_id; // Forget the ChannelMonitor update
                let fulfill_resp = self.get_update_fulfill_htlc(htlc_id_arg, payment_preimage_arg, logger);
                self.context.latest_monitor_update_id = mon_update_id;
@@ -2451,10 +2681,9 @@ impl<SP: Deref> Channel<SP> where
                // caller thought we could have something claimed (cause we wouldn't have accepted in an
                // incoming HTLC anyway). If we got to ShutdownComplete, callers aren't allowed to call us,
                // either.
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        panic!("Was asked to fulfill an HTLC when channel was not in an operational state");
                }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
                // ChannelManager may generate duplicate claims/fails due to HTLC update events from
                // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
@@ -2507,7 +2736,7 @@ impl<SP: Deref> Channel<SP> where
                        }],
                };
 
-               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
+               if self.context.channel_state.should_force_holding_cell() {
                        // Note that this condition is the same as the assertion in
                        // `claim_htlc_while_disconnected_dropping_mon_update` and must match exactly -
                        // `claim_htlc_while_disconnected_dropping_mon_update` would not work correctly if we
@@ -2535,7 +2764,7 @@ impl<SP: Deref> Channel<SP> where
                                        _ => {}
                                }
                        }
-                       log_trace!(logger, "Adding HTLC claim to holding_cell in channel {}! Current state: {}", &self.context.channel_id(), self.context.channel_state);
+                       log_trace!(logger, "Adding HTLC claim to holding_cell in channel {}! Current state: {}", &self.context.channel_id(), self.context.channel_state.to_u32());
                        self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::ClaimHTLC {
                                payment_preimage: payment_preimage_arg, htlc_id: htlc_id_arg,
                        });
@@ -2630,10 +2859,9 @@ impl<SP: Deref> Channel<SP> where
        /// [`ChannelError::Ignore`].
        fn fail_htlc<L: Deref>(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L)
        -> Result<Option<msgs::UpdateFailHTLC>, ChannelError> where L::Target: Logger {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        panic!("Was asked to fail an HTLC when channel was not in an operational state");
                }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
                // ChannelManager may generate duplicate claims/fails due to HTLC update events from
                // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
@@ -2667,7 +2895,7 @@ impl<SP: Deref> Channel<SP> where
                        return Ok(None);
                }
 
-               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
+               if self.context.channel_state.should_force_holding_cell() {
                        debug_assert!(force_holding_cell, "!force_holding_cell is only called when emptying the holding cell, so we shouldn't end up back in it!");
                        force_holding_cell = true;
                }
@@ -2726,7 +2954,7 @@ impl<SP: Deref> Channel<SP> where
                if !self.context.is_outbound() {
                        return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
                }
-               if self.context.channel_state & !(ChannelState::MonitorUpdateInProgress as u32) != ChannelState::FundingCreated as u32 {
+               if !matches!(self.context.channel_state, ChannelState::FundingNegotiated) {
                        return Err(ChannelError::Close("Received funding_signed in strange state!".to_owned()));
                }
                if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
@@ -2791,11 +3019,11 @@ impl<SP: Deref> Channel<SP> where
                        counterparty_initial_commitment_tx.to_broadcaster_value_sat(),
                        counterparty_initial_commitment_tx.to_countersignatory_value_sat(), logger);
 
-               assert_eq!(self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32), 0); // We have no had any monitor(s) yet to fail update!
+               assert!(!self.context.channel_state.is_monitor_update_in_progress()); // We have no had any monitor(s) yet to fail update!
                if self.context.is_batch_funding() {
-                       self.context.channel_state = ChannelState::FundingSent as u32 | ChannelState::WaitingForBatch as u32;
+                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH);
                } else {
-                       self.context.channel_state = ChannelState::FundingSent as u32;
+                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
                }
                self.context.cur_holder_commitment_transaction_number -= 1;
                self.context.cur_counterparty_commitment_transaction_number -= 1;
@@ -2813,7 +3041,7 @@ impl<SP: Deref> Channel<SP> where
        /// treated as a non-batch channel going forward.
        pub fn set_batch_ready(&mut self) {
                self.context.is_batch_funding = None;
-               self.context.channel_state &= !(ChannelState::WaitingForBatch as u32);
+               self.context.channel_state.clear_waiting_for_batch();
        }
 
        /// Handles a channel_ready message from our peer. If we've already sent our channel_ready
@@ -2827,7 +3055,7 @@ impl<SP: Deref> Channel<SP> where
                NS::Target: NodeSigner,
                L::Target: Logger
        {
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        self.context.workaround_lnd_bug_4006 = Some(msg.clone());
                        return Err(ChannelError::Ignore("Peer sent channel_ready when we needed a channel_reestablish. The peer is likely lnd, see https://github.com/lightningnetwork/lnd/issues/4006".to_owned()));
                }
@@ -2841,24 +3069,31 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
-               let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
-
                // Our channel_ready shouldn't have been sent if we are waiting for other channels in the
                // batch, but we can receive channel_ready messages.
-               debug_assert!(
-                       non_shutdown_state & ChannelState::OurChannelReady as u32 == 0 ||
-                       non_shutdown_state & ChannelState::WaitingForBatch as u32 == 0
-               );
-               if non_shutdown_state & !(ChannelState::WaitingForBatch as u32) == ChannelState::FundingSent as u32 {
-                       self.context.channel_state |= ChannelState::TheirChannelReady as u32;
-               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurChannelReady as u32) {
-                       self.context.channel_state = ChannelState::ChannelReady as u32 | (self.context.channel_state & MULTI_STATE_FLAGS);
-                       self.context.update_time_counter += 1;
-               } else if self.context.channel_state & (ChannelState::ChannelReady as u32) != 0 ||
-                       // If we reconnected before sending our `channel_ready` they may still resend theirs:
-                       (self.context.channel_state & (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32) ==
-                                             (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32))
-               {
+               let mut check_reconnection = false;
+               match &self.context.channel_state {
+                       ChannelState::AwaitingChannelReady(flags) => {
+                               let flags = *flags & !FundedStateFlags::ALL;
+                               debug_assert!(!flags.is_set(AwaitingChannelReadyFlags::OUR_CHANNEL_READY) || !flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH));
+                               if flags & !AwaitingChannelReadyFlags::WAITING_FOR_BATCH == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY {
+                                       // If we reconnected before sending our `channel_ready` they may still resend theirs.
+                                       check_reconnection = true;
+                               } else if (flags & !AwaitingChannelReadyFlags::WAITING_FOR_BATCH).is_empty() {
+                                       self.context.channel_state.set_their_channel_ready();
+                               } else if flags == AwaitingChannelReadyFlags::OUR_CHANNEL_READY {
+                                       self.context.channel_state = ChannelState::ChannelReady(self.context.channel_state.with_funded_state_flags_mask().into());
+                                       self.context.update_time_counter += 1;
+                               } else {
+                                       // We're in `WAITING_FOR_BATCH`, so we should wait until we're ready.
+                                       debug_assert!(flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH));
+                               }
+                       }
+                       // If we reconnected before sending our `channel_ready` they may still resend theirs.
+                       ChannelState::ChannelReady(_) => check_reconnection = true,
+                       _ => return Err(ChannelError::Close("Peer sent a channel_ready at a strange time".to_owned())),
+               }
+               if check_reconnection {
                        // They probably disconnected/reconnected and re-sent the channel_ready, which is
                        // required, or they're sending a fresh SCID alias.
                        let expected_point =
@@ -2882,8 +3117,6 @@ impl<SP: Deref> Channel<SP> where
                                return Err(ChannelError::Close("Peer sent a reconnect channel_ready with a different point".to_owned()));
                        }
                        return Ok(None);
-               } else {
-                       return Err(ChannelError::Close("Peer sent a channel_ready at a strange time".to_owned()));
                }
 
                self.context.counterparty_prev_commitment_point = self.context.counterparty_cur_commitment_point;
@@ -2901,17 +3134,18 @@ impl<SP: Deref> Channel<SP> where
        where F: for<'a> Fn(&'a Self, PendingHTLCStatus, u16) -> PendingHTLCStatus,
                FE::Target: FeeEstimator, L::Target: Logger,
        {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
+                       return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
+               }
                // We can't accept HTLCs sent after we've sent a shutdown.
-               let local_sent_shutdown = (self.context.channel_state & (ChannelState::ChannelReady as u32 | ChannelState::LocalShutdownSent as u32)) != (ChannelState::ChannelReady as u32);
-               if local_sent_shutdown {
+               if self.context.channel_state.is_local_shutdown_sent() {
                        pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x4000|8);
                }
                // If the remote has sent a shutdown prior to adding this HTLC, then they are in violation of the spec.
-               let remote_sent_shutdown = (self.context.channel_state & (ChannelState::ChannelReady as u32 | ChannelState::RemoteShutdownSent as u32)) != (ChannelState::ChannelReady as u32);
-               if remote_sent_shutdown {
+               if self.context.channel_state.is_remote_shutdown_sent() {
                        return Err(ChannelError::Close("Got add HTLC message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent update_add_htlc when we needed a channel_reestablish".to_owned()));
                }
                if msg.amount_msat > self.context.channel_value_satoshis * 1000 {
@@ -3046,7 +3280,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Close("Remote provided CLTV expiry in seconds instead of block height".to_owned()));
                }
 
-               if self.context.channel_state & ChannelState::LocalShutdownSent as u32 != 0 {
+               if self.context.channel_state.is_local_shutdown_sent() {
                        if let PendingHTLCStatus::Forward(_) = pending_forward_status {
                                panic!("ChannelManager shouldn't be trying to add a forwardable HTLC after we've started closing");
                        }
@@ -3096,10 +3330,10 @@ impl<SP: Deref> Channel<SP> where
        }
 
        pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<(HTLCSource, u64), ChannelError> {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent update_fulfill_htlc when we needed a channel_reestablish".to_owned()));
                }
 
@@ -3107,10 +3341,10 @@ impl<SP: Deref> Channel<SP> where
        }
 
        pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got fail HTLC message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent update_fail_htlc when we needed a channel_reestablish".to_owned()));
                }
 
@@ -3119,10 +3353,10 @@ impl<SP: Deref> Channel<SP> where
        }
 
        pub fn update_fail_malformed_htlc(&mut self, msg: &msgs::UpdateFailMalformedHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got fail malformed HTLC message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent update_fail_malformed_htlc when we needed a channel_reestablish".to_owned()));
                }
 
@@ -3133,13 +3367,13 @@ impl<SP: Deref> Channel<SP> where
        pub fn commitment_signed<L: Deref>(&mut self, msg: &msgs::CommitmentSigned, logger: &L) -> Result<Option<ChannelMonitorUpdate>, ChannelError>
                where L::Target: Logger
        {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got commitment signed message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent commitment_signed when we needed a channel_reestablish".to_owned()));
                }
-               if self.context.channel_state & BOTH_SIDES_SHUTDOWN_MASK == BOTH_SIDES_SHUTDOWN_MASK && self.context.last_sent_closing_fee.is_some() {
+               if self.context.channel_state.is_both_sides_shutdown() && self.context.last_sent_closing_fee.is_some() {
                        return Err(ChannelError::Close("Peer sent commitment_signed after we'd started exchanging closing_signeds".to_owned()));
                }
 
@@ -3314,11 +3548,11 @@ impl<SP: Deref> Channel<SP> where
                // build_commitment_no_status_check() next which will reset this to RAAFirst.
                self.context.resend_order = RAACommitmentOrder::CommitmentFirst;
 
-               if (self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32) != 0 {
+               if self.context.channel_state.is_monitor_update_in_progress() {
                        // In case we initially failed monitor updating without requiring a response, we need
                        // to make sure the RAA gets sent first.
                        self.context.monitor_pending_revoke_and_ack = true;
-                       if need_commitment && (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
+                       if need_commitment && !self.context.channel_state.is_awaiting_remote_revoke() {
                                // If we were going to send a commitment_signed after the RAA, go ahead and do all
                                // the corresponding HTLC status updates so that
                                // get_last_commitment_update_for_send includes the right HTLCs.
@@ -3334,7 +3568,7 @@ impl<SP: Deref> Channel<SP> where
                        return Ok(self.push_ret_blockable_mon_update(monitor_update));
                }
 
-               let need_commitment_signed = if need_commitment && (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == 0 {
+               let need_commitment_signed = if need_commitment && !self.context.channel_state.is_awaiting_remote_revoke() {
                        // If we're AwaitingRemoteRevoke we can't send a new commitment here, but that's ok -
                        // we'll send one right away when we get the revoke_and_ack when we
                        // free_holding_cell_htlcs().
@@ -3360,8 +3594,7 @@ impl<SP: Deref> Channel<SP> where
        ) -> (Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>)
        where F::Target: FeeEstimator, L::Target: Logger
        {
-               if self.context.channel_state & !STATE_FLAGS >= ChannelState::ChannelReady as u32 &&
-                  (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) == 0 {
+               if matches!(self.context.channel_state, ChannelState::ChannelReady(_)) && !self.context.channel_state.should_force_holding_cell() {
                        self.free_holding_cell_htlcs(fee_estimator, logger)
                } else { (None, Vec::new()) }
        }
@@ -3373,7 +3606,7 @@ impl<SP: Deref> Channel<SP> where
        ) -> (Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>)
        where F::Target: FeeEstimator, L::Target: Logger
        {
-               assert_eq!(self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32, 0);
+               assert!(!self.context.channel_state.is_monitor_update_in_progress());
                if self.context.holding_cell_htlc_updates.len() != 0 || self.context.holding_cell_update_fee.is_some() {
                        log_trace!(logger, "Freeing holding cell with {} HTLC updates{} in channel {}", self.context.holding_cell_htlc_updates.len(),
                                if self.context.holding_cell_update_fee.is_some() { " and a fee update" } else { "" }, &self.context.channel_id());
@@ -3494,13 +3727,13 @@ impl<SP: Deref> Channel<SP> where
        ) -> Result<(Vec<(HTLCSource, PaymentHash)>, Option<ChannelMonitorUpdate>), ChannelError>
        where F::Target: FeeEstimator, L::Target: Logger,
        {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) {
                        return Err(ChannelError::Close("Got revoke/ACK message when channel was not in an operational state".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent revoke_and_ack when we needed a channel_reestablish".to_owned()));
                }
-               if self.context.channel_state & BOTH_SIDES_SHUTDOWN_MASK == BOTH_SIDES_SHUTDOWN_MASK && self.context.last_sent_closing_fee.is_some() {
+               if self.context.channel_state.is_both_sides_shutdown() && self.context.last_sent_closing_fee.is_some() {
                        return Err(ChannelError::Close("Peer sent revoke_and_ack after we'd started exchanging closing_signeds".to_owned()));
                }
 
@@ -3512,7 +3745,7 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
-               if self.context.channel_state & ChannelState::AwaitingRemoteRevoke as u32 == 0 {
+               if !self.context.channel_state.is_awaiting_remote_revoke() {
                        // Our counterparty seems to have burned their coins to us (by revoking a state when we
                        // haven't given them a new commitment transaction to broadcast). We should probably
                        // take advantage of this by updating our channel monitor, sending them an error, and
@@ -3556,7 +3789,7 @@ impl<SP: Deref> Channel<SP> where
                // (note that we may still fail to generate the new commitment_signed message, but that's
                // OK, we step the channel here and *then* if the new generation fails we can fail the
                // channel based on that, but stepping stuff here should be safe either way.
-               self.context.channel_state &= !(ChannelState::AwaitingRemoteRevoke as u32);
+               self.context.channel_state.clear_awaiting_remote_revoke();
                self.context.sent_message_awaiting_response = None;
                self.context.counterparty_prev_commitment_point = self.context.counterparty_cur_commitment_point;
                self.context.counterparty_cur_commitment_point = Some(msg.next_per_commitment_point);
@@ -3698,7 +3931,7 @@ impl<SP: Deref> Channel<SP> where
                        }
                }
 
-               if (self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32) == ChannelState::MonitorUpdateInProgress as u32 {
+               if self.context.channel_state.is_monitor_update_in_progress() {
                        // We can't actually generate a new commitment transaction (incl by freeing holding
                        // cells) while we can't update the monitor, so we just return what we have.
                        if require_commitment {
@@ -3820,7 +4053,7 @@ impl<SP: Deref> Channel<SP> where
                        return None;
                }
 
-               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
+               if self.context.channel_state.is_awaiting_remote_revoke() || self.context.channel_state.is_monitor_update_in_progress() {
                        force_holding_cell = true;
                }
 
@@ -3845,12 +4078,12 @@ impl<SP: Deref> Channel<SP> where
        /// completed.
        /// May return `Err(())`, which implies [`ChannelContext::force_shutdown`] should be called immediately.
        pub fn remove_uncommitted_htlcs_and_mark_paused<L: Deref>(&mut self, logger: &L) -> Result<(), ()> where L::Target: Logger {
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
-               if self.context.channel_state & !STATE_FLAGS < ChannelState::FundingSent as u32 {
-                       return Err(());
+               assert!(!matches!(self.context.channel_state, ChannelState::ShutdownComplete));
+               if self.context.channel_state.is_pre_funded_state() {
+                       return Err(())
                }
 
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == (ChannelState::PeerDisconnected as u32) {
+               if self.context.channel_state.is_peer_disconnected() {
                        // While the below code should be idempotent, it's simpler to just return early, as
                        // redundant disconnect events can fire, though they should be rare.
                        return Ok(());
@@ -3912,7 +4145,7 @@ impl<SP: Deref> Channel<SP> where
 
                self.context.sent_message_awaiting_response = None;
 
-               self.context.channel_state |= ChannelState::PeerDisconnected as u32;
+               self.context.channel_state.set_peer_disconnected();
                log_trace!(logger, "Peer disconnection resulted in {} remote-announced HTLC drops on channel {}", inbound_drop_count, &self.context.channel_id());
                Ok(())
        }
@@ -3939,7 +4172,7 @@ impl<SP: Deref> Channel<SP> where
                self.context.monitor_pending_forwards.append(&mut pending_forwards);
                self.context.monitor_pending_failures.append(&mut pending_fails);
                self.context.monitor_pending_finalized_fulfills.append(&mut pending_finalized_claimed_htlcs);
-               self.context.channel_state |= ChannelState::MonitorUpdateInProgress as u32;
+               self.context.channel_state.set_monitor_update_in_progress();
        }
 
        /// Indicates that the latest ChannelMonitor update has been committed by the client
@@ -3953,19 +4186,22 @@ impl<SP: Deref> Channel<SP> where
                L::Target: Logger,
                NS::Target: NodeSigner
        {
-               assert_eq!(self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32, ChannelState::MonitorUpdateInProgress as u32);
-               self.context.channel_state &= !(ChannelState::MonitorUpdateInProgress as u32);
+               assert!(self.context.channel_state.is_monitor_update_in_progress());
+               self.context.channel_state.clear_monitor_update_in_progress();
 
-               // If we're past (or at) the FundingSent stage on an outbound channel, try to
+               // If we're past (or at) the AwaitingChannelReady stage on an outbound channel, try to
                // (re-)broadcast the funding transaction as we may have declined to broadcast it when we
                // first received the funding_signed.
                let mut funding_broadcastable =
-                       if self.context.is_outbound() && self.context.channel_state & !STATE_FLAGS >= ChannelState::FundingSent as u32 && self.context.channel_state & ChannelState::WaitingForBatch as u32 == 0 {
+                       if self.context.is_outbound() &&
+                               matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(flags) if !flags.is_set(AwaitingChannelReadyFlags::WAITING_FOR_BATCH)) ||
+                               matches!(self.context.channel_state, ChannelState::ChannelReady(_))
+                       {
                                self.context.funding_transaction.take()
                        } else { None };
                // That said, if the funding transaction is already confirmed (ie we're active with a
                // minimum_depth over 0) don't bother re-broadcasting the confirmed funding tx.
-               if self.context.channel_state & !STATE_FLAGS >= ChannelState::ChannelReady as u32 && self.context.minimum_depth != Some(0) {
+               if matches!(self.context.channel_state, ChannelState::ChannelReady(_)) && self.context.minimum_depth != Some(0) {
                        funding_broadcastable = None;
                }
 
@@ -3996,7 +4232,7 @@ impl<SP: Deref> Channel<SP> where
                let mut finalized_claimed_htlcs = Vec::new();
                mem::swap(&mut finalized_claimed_htlcs, &mut self.context.monitor_pending_finalized_fulfills);
 
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) != 0 {
+               if self.context.channel_state.is_peer_disconnected() {
                        self.context.monitor_pending_revoke_and_ack = false;
                        self.context.monitor_pending_commitment_signed = false;
                        return MonitorRestoreUpdates {
@@ -4033,7 +4269,7 @@ impl<SP: Deref> Channel<SP> where
                if self.context.is_outbound() {
                        return Err(ChannelError::Close("Non-funding remote tried to update channel fee".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish".to_owned()));
                }
                Channel::<SP>::check_remote_fee(&self.context.channel_type, fee_estimator, msg.feerate_per_kw, Some(self.context.feerate_per_kw), logger)?;
@@ -4184,7 +4420,7 @@ impl<SP: Deref> Channel<SP> where
 
        /// Gets the `Shutdown` message we should send our peer on reconnect, if any.
        pub fn get_outbound_shutdown(&self) -> Option<msgs::Shutdown> {
-               if self.context.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 {
+               if self.context.channel_state.is_local_shutdown_sent() {
                        assert!(self.context.shutdown_scriptpubkey.is_some());
                        Some(msgs::Shutdown {
                                channel_id: self.context.channel_id,
@@ -4208,7 +4444,7 @@ impl<SP: Deref> Channel<SP> where
                L::Target: Logger,
                NS::Target: NodeSigner
        {
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == 0 {
+               if !self.context.channel_state.is_peer_disconnected() {
                        // While BOLT 2 doesn't indicate explicitly we should error this channel here, it
                        // almost certainly indicates we are going to end up out-of-sync in some way, so we
                        // just close here instead of trying to recover.
@@ -4258,17 +4494,17 @@ impl<SP: Deref> Channel<SP> where
 
                // Go ahead and unmark PeerDisconnected as various calls we may make check for it (and all
                // remaining cases either succeed or ErrorMessage-fail).
-               self.context.channel_state &= !(ChannelState::PeerDisconnected as u32);
+               self.context.channel_state.clear_peer_disconnected();
                self.context.sent_message_awaiting_response = None;
 
                let shutdown_msg = self.get_outbound_shutdown();
 
                let announcement_sigs = self.get_announcement_sigs(node_signer, chain_hash, user_config, best_block.height(), logger);
 
-               if self.context.channel_state & (ChannelState::FundingSent as u32) == ChannelState::FundingSent as u32 {
+               if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(_)) {
                        // If we're waiting on a monitor update, we shouldn't re-send any channel_ready's.
-                       if self.context.channel_state & (ChannelState::OurChannelReady as u32) == 0 ||
-                                       self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32) != 0 {
+                       if !self.context.channel_state.is_our_channel_ready() ||
+                                       self.context.channel_state.is_monitor_update_in_progress() {
                                if msg.next_remote_commitment_number != 0 {
                                        return Err(ChannelError::Close("Peer claimed they saw a revoke_and_ack but we haven't sent channel_ready yet".to_owned()));
                                }
@@ -4300,7 +4536,7 @@ impl<SP: Deref> Channel<SP> where
                        // Note that if we need to repeat our ChannelReady we'll do that in the next if block.
                        None
                } else if msg.next_remote_commitment_number + 1 == our_commitment_transaction {
-                       if self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32) != 0 {
+                       if self.context.channel_state.is_monitor_update_in_progress() {
                                self.context.monitor_pending_revoke_and_ack = true;
                                None
                        } else {
@@ -4319,7 +4555,7 @@ impl<SP: Deref> Channel<SP> where
                // revoke_and_ack, not on sending commitment_signed, so we add one if have
                // AwaitingRemoteRevoke set, which indicates we sent a commitment_signed but haven't gotten
                // the corresponding revoke_and_ack back yet.
-               let is_awaiting_remote_revoke = self.context.channel_state & ChannelState::AwaitingRemoteRevoke as u32 != 0;
+               let is_awaiting_remote_revoke = self.context.channel_state.is_awaiting_remote_revoke();
                if is_awaiting_remote_revoke && !self.is_awaiting_monitor_update() {
                        self.mark_awaiting_response();
                }
@@ -4355,7 +4591,7 @@ impl<SP: Deref> Channel<SP> where
                                log_debug!(logger, "Reconnected channel {} with only lost remote commitment tx", &self.context.channel_id());
                        }
 
-                       if self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32) != 0 {
+                       if self.context.channel_state.is_monitor_update_in_progress() {
                                self.context.monitor_pending_commitment_signed = true;
                                Ok(ReestablishResponses {
                                        channel_ready, shutdown_msg, announcement_sigs,
@@ -4542,10 +4778,10 @@ impl<SP: Deref> Channel<SP> where
                &mut self, signer_provider: &SP, their_features: &InitFeatures, msg: &msgs::Shutdown
        ) -> Result<(Option<msgs::Shutdown>, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), ChannelError>
        {
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent shutdown when we needed a channel_reestablish".to_owned()));
                }
-               if self.context.channel_state & !STATE_FLAGS < ChannelState::FundingSent as u32 {
+               if self.context.channel_state.is_pre_funded_state() {
                        // Spec says we should fail the connection, not the channel, but that's nonsense, there
                        // are plenty of reasons you may want to fail a channel pre-funding, and spec says you
                        // can do that via error message without getting a connection fail anyway...
@@ -4556,7 +4792,7 @@ impl<SP: Deref> Channel<SP> where
                                return Err(ChannelError::Close("Got shutdown with remote pending HTLCs".to_owned()));
                        }
                }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
+               assert!(!matches!(self.context.channel_state, ChannelState::ShutdownComplete));
 
                if !script::is_bolt2_compliant(&msg.scriptpubkey, their_features) {
                        return Err(ChannelError::Warn(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_hex_string())));
@@ -4573,7 +4809,7 @@ impl<SP: Deref> Channel<SP> where
                // If we have any LocalAnnounced updates we'll probably just get back an update_fail_htlc
                // immediately after the commitment dance, but we can send a Shutdown because we won't send
                // any further commitment updates after we set LocalShutdownSent.
-               let send_shutdown = (self.context.channel_state & ChannelState::LocalShutdownSent as u32) != ChannelState::LocalShutdownSent as u32;
+               let send_shutdown = !self.context.channel_state.is_local_shutdown_sent();
 
                let update_shutdown_script = match self.context.shutdown_scriptpubkey {
                        Some(_) => false,
@@ -4593,7 +4829,7 @@ impl<SP: Deref> Channel<SP> where
 
                // From here on out, we may not fail!
 
-               self.context.channel_state |= ChannelState::RemoteShutdownSent as u32;
+               self.context.channel_state.set_remote_shutdown_sent();
                self.context.update_time_counter += 1;
 
                let monitor_update = if update_shutdown_script {
@@ -4629,7 +4865,7 @@ impl<SP: Deref> Channel<SP> where
                        }
                });
 
-               self.context.channel_state |= ChannelState::LocalShutdownSent as u32;
+               self.context.channel_state.set_local_shutdown_sent();
                self.context.update_time_counter += 1;
 
                Ok((shutdown, monitor_update, dropped_outbound_htlcs))
@@ -4663,10 +4899,10 @@ impl<SP: Deref> Channel<SP> where
                -> Result<(Option<msgs::ClosingSigned>, Option<Transaction>, Option<ShutdownResult>), ChannelError>
                where F::Target: FeeEstimator
        {
-               if self.context.channel_state & BOTH_SIDES_SHUTDOWN_MASK != BOTH_SIDES_SHUTDOWN_MASK {
+               if !self.context.channel_state.is_both_sides_shutdown() {
                        return Err(ChannelError::Close("Remote end sent us a closing_signed before both sides provided a shutdown".to_owned()));
                }
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+               if self.context.channel_state.is_peer_disconnected() {
                        return Err(ChannelError::Close("Peer sent closing_signed when we needed a channel_reestablish".to_owned()));
                }
                if !self.context.pending_inbound_htlcs.is_empty() || !self.context.pending_outbound_htlcs.is_empty() {
@@ -4680,7 +4916,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Close("Remote tried to send a closing_signed when we were supposed to propose the first one".to_owned()));
                }
 
-               if self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32 != 0 {
+               if self.context.channel_state.is_monitor_update_in_progress() {
                        self.context.pending_counterparty_closing_signed = Some(msg.clone());
                        return Ok((None, None, None));
                }
@@ -4720,7 +4956,7 @@ impl<SP: Deref> Channel<SP> where
                                        counterparty_node_id: self.context.counterparty_node_id,
                                };
                                let tx = self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
-                               self.context.channel_state = ChannelState::ShutdownComplete as u32;
+                               self.context.channel_state = ChannelState::ShutdownComplete;
                                self.context.update_time_counter += 1;
                                return Ok((None, Some(tx), Some(shutdown_result)));
                        }
@@ -4749,7 +4985,7 @@ impl<SP: Deref> Channel<SP> where
                                                                channel_id: self.context.channel_id,
                                                                counterparty_node_id: self.context.counterparty_node_id,
                                                        };
-                                                       self.context.channel_state = ChannelState::ShutdownComplete as u32;
+                                                       self.context.channel_state = ChannelState::ShutdownComplete;
                                                        self.context.update_time_counter += 1;
                                                        let tx = self.build_signed_closing_transaction(&closing_tx, &msg.signature, &sig);
                                                        (Some(tx), Some(shutdown_result))
@@ -4874,7 +5110,7 @@ impl<SP: Deref> Channel<SP> where
        }
 
        pub fn get_cur_counterparty_commitment_transaction_number(&self) -> u64 {
-               self.context.cur_counterparty_commitment_transaction_number + 1 - if self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32) != 0 { 1 } else { 0 }
+               self.context.cur_counterparty_commitment_transaction_number + 1 - if self.context.channel_state.is_awaiting_remote_revoke() { 1 } else { 0 }
        }
 
        pub fn get_revoked_counterparty_commitment_transaction_number(&self) -> u64 {
@@ -4914,7 +5150,7 @@ impl<SP: Deref> Channel<SP> where
        /// Returns true if this channel has been marked as awaiting a monitor update to move forward.
        /// Allowed in any state (including after shutdown)
        pub fn is_awaiting_monitor_update(&self) -> bool {
-               (self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32) != 0
+               self.context.channel_state.is_monitor_update_in_progress()
        }
 
        /// Gets the latest [`ChannelMonitorUpdate`] ID which has been released and is in-flight.
@@ -4956,17 +5192,18 @@ impl<SP: Deref> Channel<SP> where
        /// advanced state.
        pub fn is_awaiting_initial_mon_persist(&self) -> bool {
                if !self.is_awaiting_monitor_update() { return false; }
-               if self.context.channel_state &
-                       !(ChannelState::TheirChannelReady as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32 | ChannelState::WaitingForBatch as u32)
-                               == ChannelState::FundingSent as u32 {
+               if matches!(
+                       self.context.channel_state, ChannelState::AwaitingChannelReady(flags)
+                       if (flags & !(AwaitingChannelReadyFlags::THEIR_CHANNEL_READY | FundedStateFlags::PEER_DISCONNECTED | FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS | AwaitingChannelReadyFlags::WAITING_FOR_BATCH)).is_empty()
+               ) {
                        // If we're not a 0conf channel, we'll be waiting on a monitor update with only
-                       // FundingSent set, though our peer could have sent their channel_ready.
+                       // AwaitingChannelReady set, though our peer could have sent their channel_ready.
                        debug_assert!(self.context.minimum_depth.unwrap_or(1) > 0);
                        return true;
                }
                if self.context.cur_holder_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 &&
                        self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 {
-                       // If we're a 0-conf channel, we'll move beyond FundingSent immediately even while
+                       // If we're a 0-conf channel, we'll move beyond AwaitingChannelReady immediately even while
                        // waiting for the initial monitor persistence. Thus, we check if our commitment
                        // transaction numbers have both been iterated only exactly once (for the
                        // funding_signed), and we're awaiting monitor update.
@@ -4988,27 +5225,25 @@ impl<SP: Deref> Channel<SP> where
 
        /// Returns true if our channel_ready has been sent
        pub fn is_our_channel_ready(&self) -> bool {
-               (self.context.channel_state & ChannelState::OurChannelReady as u32) != 0 || self.context.channel_state & !STATE_FLAGS >= ChannelState::ChannelReady as u32
+               matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(flags) if flags.is_set(AwaitingChannelReadyFlags::OUR_CHANNEL_READY)) ||
+                       matches!(self.context.channel_state, ChannelState::ChannelReady(_))
        }
 
        /// Returns true if our peer has either initiated or agreed to shut down the channel.
        pub fn received_shutdown(&self) -> bool {
-               (self.context.channel_state & ChannelState::RemoteShutdownSent as u32) != 0
+               self.context.channel_state.is_remote_shutdown_sent()
        }
 
        /// Returns true if we either initiated or agreed to shut down the channel.
        pub fn sent_shutdown(&self) -> bool {
-               (self.context.channel_state & ChannelState::LocalShutdownSent as u32) != 0
+               self.context.channel_state.is_local_shutdown_sent()
        }
 
        /// Returns true if this channel is fully shut down. True here implies that no further actions
        /// may/will be taken on this channel, and thus this object should be freed. Any future changes
        /// will be handled appropriately by the chain monitor.
        pub fn is_shutdown(&self) -> bool {
-               if (self.context.channel_state & ChannelState::ShutdownComplete as u32) == ChannelState::ShutdownComplete as u32  {
-                       assert!(self.context.channel_state == ChannelState::ShutdownComplete as u32);
-                       true
-               } else { false }
+               matches!(self.context.channel_state, ChannelState::ShutdownComplete)
        }
 
        pub fn channel_update_status(&self) -> ChannelUpdateStatus {
@@ -5045,35 +5280,36 @@ impl<SP: Deref> Channel<SP> where
 
                // Note that we don't include ChannelState::WaitingForBatch as we don't want to send
                // channel_ready until the entire batch is ready.
-               let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
-               let need_commitment_update = if non_shutdown_state == ChannelState::FundingSent as u32 {
-                       self.context.channel_state |= ChannelState::OurChannelReady as u32;
+               let need_commitment_update = if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if (f & !FundedStateFlags::ALL).is_empty()) {
+                       self.context.channel_state.set_our_channel_ready();
                        true
-               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32) {
-                       self.context.channel_state = ChannelState::ChannelReady as u32 | (self.context.channel_state & MULTI_STATE_FLAGS);
+               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f & !FundedStateFlags::ALL == AwaitingChannelReadyFlags::THEIR_CHANNEL_READY) {
+                       self.context.channel_state = ChannelState::ChannelReady(self.context.channel_state.with_funded_state_flags_mask().into());
                        self.context.update_time_counter += 1;
                        true
-               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurChannelReady as u32) {
+               } else if matches!(self.context.channel_state, ChannelState::AwaitingChannelReady(f) if f & !FundedStateFlags::ALL == AwaitingChannelReadyFlags::OUR_CHANNEL_READY) {
                        // We got a reorg but not enough to trigger a force close, just ignore.
                        false
                } else {
-                       if self.context.funding_tx_confirmation_height != 0 && self.context.channel_state & !STATE_FLAGS < ChannelState::ChannelReady as u32 {
+                       if self.context.funding_tx_confirmation_height != 0 &&
+                               self.context.channel_state < ChannelState::ChannelReady(ChannelReadyFlags::new())
+                       {
                                // We should never see a funding transaction on-chain until we've received
                                // funding_signed (if we're an outbound channel), or seen funding_generated (if we're
                                // an inbound channel - before that we have no known funding TXID). The fuzzer,
                                // however, may do this and we shouldn't treat it as a bug.
                                #[cfg(not(fuzzing))]
-                               panic!("Started confirming a channel in a state pre-FundingSent: {}.\n\
+                               panic!("Started confirming a channel in a state pre-AwaitingChannelReady: {}.\n\
                                        Do NOT broadcast a funding transaction manually - let LDK do it for you!",
-                                       self.context.channel_state);
+                                       self.context.channel_state.to_u32());
                        }
                        // We got a reorg but not enough to trigger a force close, just ignore.
                        false
                };
 
                if need_commitment_update {
-                       if self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32) == 0 {
-                               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == 0 {
+                       if !self.context.channel_state.is_monitor_update_in_progress() {
+                               if !self.context.channel_state.is_peer_disconnected() {
                                        let next_per_commitment_point =
                                                self.context.holder_signer.as_ref().get_per_commitment_point(INITIAL_COMMITMENT_NUMBER - 1, &self.context.secp_ctx);
                                        return Some(msgs::ChannelReady {
@@ -5227,9 +5463,8 @@ impl<SP: Deref> Channel<SP> where
                        return Ok((Some(channel_ready), timed_out_htlcs, announcement_sigs));
                }
 
-               let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
-               if non_shutdown_state & !STATE_FLAGS >= ChannelState::ChannelReady as u32 ||
-                  (non_shutdown_state & ChannelState::OurChannelReady as u32) == ChannelState::OurChannelReady as u32 {
+               if matches!(self.context.channel_state, ChannelState::ChannelReady(_)) ||
+                       self.context.channel_state.is_our_channel_ready() {
                        let mut funding_tx_confirmations = height as i64 - self.context.funding_tx_confirmation_height as i64 + 1;
                        if self.context.funding_tx_confirmation_height == 0 {
                                // Note that check_get_channel_ready may reset funding_tx_confirmation_height to
@@ -5256,8 +5491,8 @@ impl<SP: Deref> Channel<SP> where
                                height >= self.context.channel_creation_height + FUNDING_CONF_DEADLINE_BLOCKS {
                        log_info!(logger, "Closing channel {} due to funding timeout", &self.context.channel_id);
                        // If funding_tx_confirmed_in is unset, the channel must not be active
-                       assert!(non_shutdown_state & !STATE_FLAGS <= ChannelState::ChannelReady as u32);
-                       assert_eq!(non_shutdown_state & ChannelState::OurChannelReady as u32, 0);
+                       assert!(self.context.channel_state <= ChannelState::ChannelReady(ChannelReadyFlags::new()));
+                       assert!(!self.context.channel_state.is_our_channel_ready());
                        return Err(ClosureReason::FundingTimedOut);
                }
 
@@ -5355,7 +5590,7 @@ impl<SP: Deref> Channel<SP> where
                        return None;
                }
 
-               if self.context.channel_state & ChannelState::PeerDisconnected as u32 != 0 {
+               if self.context.channel_state.is_peer_disconnected() {
                        log_trace!(logger, "Cannot create an announcement_signatures as our peer is disconnected");
                        return None;
                }
@@ -5493,7 +5728,7 @@ impl<SP: Deref> Channel<SP> where
        /// May panic if called on a channel that wasn't immediately-previously
        /// self.remove_uncommitted_htlcs_and_mark_paused()'d
        pub fn get_channel_reestablish<L: Deref>(&mut self, logger: &L) -> msgs::ChannelReestablish where L::Target: Logger {
-               assert_eq!(self.context.channel_state & ChannelState::PeerDisconnected as u32, ChannelState::PeerDisconnected as u32);
+               assert!(self.context.channel_state.is_peer_disconnected());
                assert_ne!(self.context.cur_counterparty_commitment_transaction_number, INITIAL_COMMITMENT_NUMBER);
                // Prior to static_remotekey, my_current_per_commitment_point was critical to claiming
                // current to_remote balances. However, it no longer has any use, and thus is now simply
@@ -5529,7 +5764,7 @@ impl<SP: Deref> Channel<SP> where
                        // (which is one further, as they always revoke previous commitment transaction, not
                        // the one we send) so we have to decrement by 1. Note that if
                        // cur_counterparty_commitment_transaction_number is INITIAL_COMMITMENT_NUMBER we will have
-                       // dropped this channel on disconnect as it hasn't yet reached FundingSent so we can't
+                       // dropped this channel on disconnect as it hasn't yet reached AwaitingChannelReady so we can't
                        // overflow here.
                        next_remote_commitment_number: INITIAL_COMMITMENT_NUMBER - self.context.cur_counterparty_commitment_transaction_number - 1,
                        your_last_per_commitment_secret: remote_last_secret,
@@ -5591,7 +5826,10 @@ impl<SP: Deref> Channel<SP> where
        ) -> Result<Option<msgs::UpdateAddHTLC>, ChannelError>
        where F::Target: FeeEstimator, L::Target: Logger
        {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32 | BOTH_SIDES_SHUTDOWN_MASK)) != (ChannelState::ChannelReady as u32) {
+               if !matches!(self.context.channel_state, ChannelState::ChannelReady(_)) ||
+                       self.context.channel_state.is_local_shutdown_sent() ||
+                       self.context.channel_state.is_remote_shutdown_sent()
+               {
                        return Err(ChannelError::Ignore("Cannot send HTLC until channel is fully established and we haven't started shutting down".to_owned()));
                }
                let channel_total_msat = self.context.channel_value_satoshis * 1000;
@@ -5614,7 +5852,7 @@ impl<SP: Deref> Channel<SP> where
                                available_balances.next_outbound_htlc_limit_msat)));
                }
 
-               if (self.context.channel_state & (ChannelState::PeerDisconnected as u32)) != 0 {
+               if self.context.channel_state.is_peer_disconnected() {
                        // Note that this should never really happen, if we're !is_live() on receipt of an
                        // incoming HTLC for relay will result in us rejecting the HTLC and we won't allow
                        // the user to send directly into a !is_live() channel. However, if we
@@ -5624,7 +5862,7 @@ impl<SP: Deref> Channel<SP> where
                        return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned()));
                }
 
-               let need_holding_cell = (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0;
+               let need_holding_cell = self.context.channel_state.should_force_holding_cell();
                log_debug!(logger, "Pushing new outbound HTLC with hash {} for {} msat {}",
                        payment_hash, amount_msat,
                        if force_holding_cell { "into holding cell" }
@@ -5731,7 +5969,7 @@ impl<SP: Deref> Channel<SP> where
                                to_countersignatory_value_sat: Some(counterparty_commitment_tx.to_countersignatory_value_sat()),
                        }]
                };
-               self.context.channel_state |= ChannelState::AwaitingRemoteRevoke as u32;
+               self.context.channel_state.set_awaiting_remote_revoke();
                monitor_update
        }
 
@@ -5877,26 +6115,24 @@ impl<SP: Deref> Channel<SP> where
                                return Err(APIError::APIMisuseError{err: "Cannot begin shutdown with pending HTLCs. Process pending events first".to_owned()});
                        }
                }
-               if self.context.channel_state & BOTH_SIDES_SHUTDOWN_MASK != 0 {
-                       if (self.context.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
-                               return Err(APIError::APIMisuseError{err: "Shutdown already in progress".to_owned()});
-                       }
-                       else if (self.context.channel_state & ChannelState::RemoteShutdownSent as u32) == ChannelState::RemoteShutdownSent as u32 {
-                               return Err(APIError::ChannelUnavailable{err: "Shutdown already in progress by remote".to_owned()});
-                       }
+               if self.context.channel_state.is_local_shutdown_sent() {
+                       return Err(APIError::APIMisuseError{err: "Shutdown already in progress".to_owned()});
+               }
+               else if self.context.channel_state.is_remote_shutdown_sent() {
+                       return Err(APIError::ChannelUnavailable{err: "Shutdown already in progress by remote".to_owned()});
                }
                if self.context.shutdown_scriptpubkey.is_some() && override_shutdown_script.is_some() {
                        return Err(APIError::APIMisuseError{err: "Cannot override shutdown script for a channel with one already set".to_owned()});
                }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32) != 0 {
+               assert!(!matches!(self.context.channel_state, ChannelState::ShutdownComplete));
+               if self.context.channel_state.is_peer_disconnected() || self.context.channel_state.is_monitor_update_in_progress() {
                        return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?".to_owned()});
                }
 
                // If we haven't funded the channel yet, we don't need to bother ensuring the shutdown
                // script is set, we just force-close and call it a day.
                let mut chan_closed = false;
-               if self.context.channel_state & !STATE_FLAGS < ChannelState::FundingSent as u32 {
+               if self.context.channel_state.is_pre_funded_state() {
                        chan_closed = true;
                }
 
@@ -5925,7 +6161,7 @@ impl<SP: Deref> Channel<SP> where
 
                // From here on out, we may not fail!
                self.context.target_closing_feerate_sats_per_kw = target_feerate_sats_per_kw;
-               let shutdown_result = if self.context.channel_state & !STATE_FLAGS < ChannelState::FundingSent as u32 {
+               let shutdown_result = if self.context.channel_state.is_pre_funded_state() {
                        let shutdown_result = ShutdownResult {
                                monitor_update: None,
                                dropped_outbound_htlcs: Vec::new(),
@@ -5933,10 +6169,10 @@ impl<SP: Deref> Channel<SP> where
                                channel_id: self.context.channel_id,
                                counterparty_node_id: self.context.counterparty_node_id,
                        };
-                       self.context.channel_state = ChannelState::ShutdownComplete as u32;
+                       self.context.channel_state = ChannelState::ShutdownComplete;
                        Some(shutdown_result)
                } else {
-                       self.context.channel_state |= ChannelState::LocalShutdownSent as u32;
+                       self.context.channel_state.set_local_shutdown_sent();
                        None
                };
                self.context.update_time_counter += 1;
@@ -6085,7 +6321,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 
                                channel_id: temporary_channel_id,
                                temporary_channel_id: Some(temporary_channel_id),
-                               channel_state: ChannelState::OurInitSent as u32,
+                               channel_state: ChannelState::NegotiatingFunding(NegotiatingFundingFlags::OUR_INIT_SENT),
                                announcement_sigs_state: AnnouncementSigsState::NotSent,
                                secp_ctx,
                                channel_value_satoshis,
@@ -6214,7 +6450,10 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                if !self.context.is_outbound() {
                        panic!("Tried to create outbound funding_created message on an inbound channel!");
                }
-               if self.context.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
+               if !matches!(
+                       self.context.channel_state, ChannelState::NegotiatingFunding(flags)
+                       if flags == (NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT)
+               ) {
                        panic!("Tried to get a funding_created messsage at a time other than immediately after initial handshake completion (or tried to get funding_created twice)");
                }
                if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
@@ -6228,7 +6467,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
 
                // Now that we're past error-generating stuff, update our local state:
 
-               self.context.channel_state = ChannelState::FundingCreated as u32;
+               self.context.channel_state = ChannelState::FundingNegotiated;
                self.context.channel_id = funding_txo.to_channel_id();
 
                // If the funding transaction is a coinbase transaction, we need to set the minimum depth to 100.
@@ -6289,7 +6528,14 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
        where
                F::Target: FeeEstimator
        {
-               if !self.context.is_outbound() || self.context.channel_state != ChannelState::OurInitSent as u32 { return Err(()); }
+               if !self.context.is_outbound() ||
+                       !matches!(
+                               self.context.channel_state, ChannelState::NegotiatingFunding(flags)
+                               if flags == NegotiatingFundingFlags::OUR_INIT_SENT
+                       )
+               {
+                       return Err(());
+               }
                if self.context.channel_type == ChannelTypeFeatures::only_static_remote_key() {
                        // We've exhausted our options
                        return Err(());
@@ -6320,7 +6566,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                if !self.context.is_outbound() {
                        panic!("Tried to open a channel for an inbound channel?");
                }
-               if self.context.channel_state != ChannelState::OurInitSent as u32 {
+               if self.context.have_received_message() {
                        panic!("Cannot generate an open_channel after we've moved forward");
                }
 
@@ -6366,7 +6612,7 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                if !self.context.is_outbound() {
                        return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
                }
-               if self.context.channel_state != ChannelState::OurInitSent as u32 {
+               if !matches!(self.context.channel_state, ChannelState::NegotiatingFunding(flags) if flags == NegotiatingFundingFlags::OUR_INIT_SENT) {
                        return Err(ChannelError::Close("Got an accept_channel message at a strange time".to_owned()));
                }
                if msg.dust_limit_satoshis > 21000000 * 100000000 {
@@ -6483,7 +6729,9 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point);
                self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey;
 
-               self.context.channel_state = ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32;
+               self.context.channel_state = ChannelState::NegotiatingFunding(
+                       NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT
+               );
                self.context.inbound_handshake_limits_override = None; // We're done enforcing limits on our peer's handshake now.
 
                Ok(())
@@ -6720,7 +6968,9 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 
                                temporary_channel_id: Some(msg.temporary_channel_id),
                                channel_id: msg.temporary_channel_id,
-                               channel_state: (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32),
+                               channel_state: ChannelState::NegotiatingFunding(
+                                       NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT
+                               ),
                                announcement_sigs_state: AnnouncementSigsState::NotSent,
                                secp_ctx,
 
@@ -6850,7 +7100,10 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                if self.context.is_outbound() {
                        panic!("Tried to send accept_channel for an outbound channel?");
                }
-               if self.context.channel_state != (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32) {
+               if !matches!(
+                       self.context.channel_state, ChannelState::NegotiatingFunding(flags)
+                       if flags == (NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT)
+               ) {
                        panic!("Tried to send accept_channel after channel had moved forward");
                }
                if self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
@@ -6930,7 +7183,10 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
                if self.context.is_outbound() {
                        return Err((self, ChannelError::Close("Received funding_created for an outbound channel?".to_owned())));
                }
-               if self.context.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
+               if !matches!(
+                       self.context.channel_state, ChannelState::NegotiatingFunding(flags)
+                       if flags == (NegotiatingFundingFlags::OUR_INIT_SENT | NegotiatingFundingFlags::THEIR_INIT_SENT)
+               ) {
                        // BOLT 2 says that if we disconnect before we send funding_signed we SHOULD NOT
                        // remember the channel, so it's safe to just send an error_message here and drop the
                        // channel.
@@ -6975,7 +7231,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 
                // Now that we're past error-generating stuff, update our local state:
 
-               self.context.channel_state = ChannelState::FundingSent as u32;
+               self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
                self.context.channel_id = funding_txo.to_channel_id();
                self.context.cur_counterparty_commitment_transaction_number -= 1;
                self.context.cur_holder_commitment_transaction_number -= 1;
@@ -7093,7 +7349,13 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                writer.write_all(&[0; 8])?;
 
                self.context.channel_id.write(writer)?;
-               (self.context.channel_state | ChannelState::PeerDisconnected as u32).write(writer)?;
+               {
+                       let mut channel_state = self.context.channel_state;
+                       if matches!(channel_state, ChannelState::AwaitingChannelReady(_)|ChannelState::ChannelReady(_)) {
+                               channel_state.set_peer_disconnected();
+                       }
+                       channel_state.to_u32().write(writer)?;
+               }
                self.context.channel_value_satoshis.write(writer)?;
 
                self.context.latest_monitor_update_id.write(writer)?;
@@ -7413,7 +7675,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                }
 
                let channel_id = Readable::read(reader)?;
-               let channel_state = Readable::read(reader)?;
+               let channel_state = ChannelState::from_u32(Readable::read(reader)?).map_err(|_| DecodeError::InvalidValue)?;
                let channel_value_satoshis = Readable::read(reader)?;
 
                let latest_monitor_update_id = Readable::read(reader)?;
@@ -7703,8 +7965,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        let mut holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
                        // If we've gotten to the funding stage of the channel, populate the signer with its
                        // required channel parameters.
-                       let non_shutdown_state = channel_state & (!MULTI_STATE_FLAGS);
-                       if non_shutdown_state & !STATE_FLAGS >= (ChannelState::FundingCreated as u32) {
+                       if channel_state >= ChannelState::FundingNegotiated {
                                holder_signer.provide_channel_parameters(&channel_parameters);
                        }
                        (channel_keys_id, holder_signer)
@@ -7930,7 +8191,7 @@ mod tests {
        use crate::ln::channel_keys::{RevocationKey, RevocationBasepoint};
        use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
        use crate::ln::channel::InitFeatures;
-       use crate::ln::channel::{Channel, ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, HTLCUpdateAwaitingACK, commit_tx_fee_msat};
+       use crate::ln::channel::{AwaitingChannelReadyFlags, Channel, ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, HTLCUpdateAwaitingACK, commit_tx_fee_msat};
        use crate::ln::channel::{MAX_FUNDING_SATOSHIS_NO_WUMBO, TOTAL_BITCOIN_SUPPLY_SATOSHIS, MIN_THEIR_CHAN_RESERVE_SATOSHIS};
        use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, NodeFeatures};
        use crate::ln::msgs;
@@ -9628,11 +9889,7 @@ mod tests {
                // as the funding transaction depends on all channels in the batch becoming ready.
                assert!(node_a_updates.channel_ready.is_none());
                assert!(node_a_updates.funding_broadcastable.is_none());
-               assert_eq!(
-                       node_a_chan.context.channel_state,
-                       ChannelState::FundingSent as u32 |
-                       ChannelState::WaitingForBatch as u32,
-               );
+               assert_eq!(node_a_chan.context.channel_state, ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH));
 
                // It is possible to receive a 0conf channel_ready from the remote node.
                node_a_chan.channel_ready(
@@ -9645,18 +9902,12 @@ mod tests {
                ).unwrap();
                assert_eq!(
                        node_a_chan.context.channel_state,
-                       ChannelState::FundingSent as u32 |
-                       ChannelState::WaitingForBatch as u32 |
-                       ChannelState::TheirChannelReady as u32,
+                       ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH | AwaitingChannelReadyFlags::THEIR_CHANNEL_READY)
                );
 
                // Clear the ChannelState::WaitingForBatch only when called by ChannelManager.
                node_a_chan.set_batch_ready();
-               assert_eq!(
-                       node_a_chan.context.channel_state,
-                       ChannelState::FundingSent as u32 |
-                       ChannelState::TheirChannelReady as u32,
-               );
+               assert_eq!(node_a_chan.context.channel_state, ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::THEIR_CHANNEL_READY));
                assert!(node_a_chan.check_get_channel_ready(0).is_some());
        }
 }