cfg-gate async signing logic
[rust-lightning] / lightning / src / ln / channel.rs
index 2dd479d21b524a9a2d8abd53fcaaed0a7e882d38..050585ef2673f81a6f9caf8484de05d2fa2bf258 100644 (file)
@@ -259,78 +259,300 @@ enum HTLCUpdateAwaitingACK {
                htlc_id: u64,
                err_packet: msgs::OnionErrorPacket,
        },
+       FailMalformedHTLC {
+               htlc_id: u64,
+               failure_code: u16,
+               sha256_of_onion: [u8; 32],
+       },
+}
+
+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;
 }
 
-/// 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.
+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;
 
@@ -512,7 +734,8 @@ struct CommitmentStats<'a> {
        htlcs_included: Vec<(HTLCOutputInCommitment, Option<&'a HTLCSource>)>, // the list of HTLCs (dust HTLCs *included*) which were not ignored when building the transaction
        local_balance_msat: u64, // local balance before fees but considering dust limits
        remote_balance_msat: u64, // remote balance before fees but considering dust limits
-       preimages: Vec<PaymentPreimage>, // preimages for successful offered HTLCs since last commitment
+       outbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful offered HTLCs since last commitment
+       inbound_htlc_preimages: Vec<PaymentPreimage>, // preimages for successful received HTLCs since last commitment
 }
 
 /// Used when calculating whether we or the remote can afford an additional HTLC.
@@ -575,7 +798,6 @@ pub(super) struct MonitorRestoreUpdates {
 pub(super) struct SignerResumeUpdates {
        pub commitment_update: Option<msgs::CommitmentUpdate>,
        pub funding_signed: Option<msgs::FundingSigned>,
-       pub funding_created: Option<msgs::FundingCreated>,
        pub channel_ready: Option<msgs::ChannelReady>,
 }
 
@@ -599,6 +821,8 @@ pub(crate) struct ShutdownResult {
        /// An unbroadcasted batch funding transaction id. The closure of this channel should be
        /// propagated to the remainder of the batch.
        pub(crate) unbroadcasted_batch_funding_txid: Option<Txid>,
+       pub(crate) channel_id: ChannelId,
+       pub(crate) counterparty_node_id: PublicKey,
 }
 
 /// If the majority of the channels funds are to the fundee and the initiator holds only just
@@ -740,7 +964,7 @@ 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
@@ -1037,49 +1261,55 @@ 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:
@@ -1331,8 +1561,8 @@ 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
@@ -1426,6 +1656,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        }
                }
 
+               let mut inbound_htlc_preimages: Vec<PaymentPreimage> = Vec::new();
+
                for ref htlc in self.pending_inbound_htlcs.iter() {
                        let (include, state_name) = match htlc.state {
                                InboundHTLCState::RemoteAnnounced(_) => (!generated_by_local, "RemoteAnnounced"),
@@ -1443,7 +1675,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                                match &htlc.state {
                                        &InboundHTLCState::LocalRemoved(ref reason) => {
                                                if generated_by_local {
-                                                       if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
+                                                       if let &InboundHTLCRemovalReason::Fulfill(preimage) = reason {
+                                                               inbound_htlc_preimages.push(preimage);
                                                                value_to_self_msat_offset += htlc.amount_msat as i64;
                                                        }
                                                }
@@ -1453,7 +1686,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        }
                }
 
-               let mut preimages: Vec<PaymentPreimage> = Vec::new();
+
+               let mut outbound_htlc_preimages: Vec<PaymentPreimage> = Vec::new();
 
                for ref htlc in self.pending_outbound_htlcs.iter() {
                        let (include, state_name) = match htlc.state {
@@ -1472,7 +1706,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        };
 
                        if let Some(preimage) = preimage_opt {
-                               preimages.push(preimage);
+                               outbound_htlc_preimages.push(preimage);
                        }
 
                        if include {
@@ -1578,7 +1812,8 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        htlcs_included,
                        local_balance_msat: value_to_self_msat as u64,
                        remote_balance_msat: value_to_remote_msat as u64,
-                       preimages
+                       inbound_htlc_preimages,
+                       outbound_htlc_preimages,
                }
        }
 
@@ -2083,11 +2318,14 @@ 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,
                }
        }
 
@@ -2126,7 +2364,7 @@ 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.
@@ -2141,14 +2379,18 @@ 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,
@@ -2158,47 +2400,17 @@ 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,
                        dropped_outbound_htlcs,
                        unbroadcasted_batch_funding_txid,
+                       channel_id: self.channel_id,
+                       counterparty_node_id: self.counterparty_node_id,
                }
        }
 
-       /// Only allowed after [`Self::channel_transaction_parameters`] is set.
-       fn get_funding_created_msg<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
-               let signature = match &self.holder_signer {
-                       // TODO (taproot|arik): move match into calling method for Taproot
-                       ChannelSignerType::Ecdsa(ecdsa) => {
-                               ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.secp_ctx)
-                                       .map(|(sig, _)| sig).ok()?
-                       },
-                       // TODO (taproot|arik)
-                       #[cfg(taproot)]
-                       _ => todo!()
-               };
-
-               if self.signer_pending_funding {
-                       log_trace!(logger, "Counterparty commitment signature ready for funding_created message: clearing signer_pending_funding");
-                       self.signer_pending_funding = false;
-               }
-
-               Some(msgs::FundingCreated {
-                       temporary_channel_id: self.temporary_channel_id.unwrap(),
-                       funding_txid: self.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().txid,
-                       funding_output_index: self.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().index,
-                       signature,
-                       #[cfg(taproot)]
-                       partial_signature_with_nonce: None,
-                       #[cfg(taproot)]
-                       next_local_nonce: None,
-               })
-       }
-
        /// Only allowed after [`Self::channel_transaction_parameters`] is set.
        fn get_funding_signed_msg<L: Deref>(&mut self, logger: &L) -> (CommitmentTransaction, Option<msgs::FundingSigned>) where L::Target: Logger {
                let counterparty_keys = self.build_remote_transaction_keys();
@@ -2212,7 +2424,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                match &self.holder_signer {
                        // TODO (arik): move match into calling method for Taproot
                        ChannelSignerType::Ecdsa(ecdsa) => {
-                               let funding_signed = ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.secp_ctx)
+                               let funding_signed = ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.secp_ctx)
                                        .map(|(signature, _)| msgs::FundingSigned {
                                                channel_id: self.channel_id(),
                                                signature,
@@ -2222,8 +2434,13 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                                        .ok();
 
                                if funding_signed.is_none() {
-                                       log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
-                                       self.signer_pending_funding = true;
+                                       #[cfg(not(async_signing))] {
+                                               panic!("Failed to get signature for funding_signed");
+                                       }
+                                       #[cfg(async_signing)] {
+                                               log_trace!(logger, "Counterparty commitment signature not available for funding_signed message; setting signer_pending_funding");
+                                               self.signer_pending_funding = true;
+                                       }
                                } else if self.signer_pending_funding {
                                        log_trace!(logger, "Counterparty commitment signature available for funding_signed message; clearing signer_pending_funding");
                                        self.signer_pending_funding = false;
@@ -2311,6 +2528,64 @@ struct CommitmentTxInfoCached {
        feerate: u32,
 }
 
+/// Contents of a wire message that fails an HTLC backwards. Useful for [`Channel::fail_htlc`] to
+/// fail with either [`msgs::UpdateFailMalformedHTLC`] or [`msgs::UpdateFailHTLC`] as needed.
+trait FailHTLCContents {
+       type Message: FailHTLCMessageName;
+       fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message;
+       fn to_inbound_htlc_state(self) -> InboundHTLCState;
+       fn to_htlc_update_awaiting_ack(self, htlc_id: u64) -> HTLCUpdateAwaitingACK;
+}
+impl FailHTLCContents for msgs::OnionErrorPacket {
+       type Message = msgs::UpdateFailHTLC;
+       fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message {
+               msgs::UpdateFailHTLC { htlc_id, channel_id, reason: self }
+       }
+       fn to_inbound_htlc_state(self) -> InboundHTLCState {
+               InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(self))
+       }
+       fn to_htlc_update_awaiting_ack(self, htlc_id: u64) -> HTLCUpdateAwaitingACK {
+               HTLCUpdateAwaitingACK::FailHTLC { htlc_id, err_packet: self }
+       }
+}
+impl FailHTLCContents for (u16, [u8; 32]) {
+       type Message = msgs::UpdateFailMalformedHTLC; // (failure_code, sha256_of_onion)
+       fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message {
+               msgs::UpdateFailMalformedHTLC {
+                       htlc_id,
+                       channel_id,
+                       failure_code: self.0,
+                       sha256_of_onion: self.1
+               }
+       }
+       fn to_inbound_htlc_state(self) -> InboundHTLCState {
+               InboundHTLCState::LocalRemoved(
+                       InboundHTLCRemovalReason::FailMalformed((self.1, self.0))
+               )
+       }
+       fn to_htlc_update_awaiting_ack(self, htlc_id: u64) -> HTLCUpdateAwaitingACK {
+               HTLCUpdateAwaitingACK::FailMalformedHTLC {
+                       htlc_id,
+                       failure_code: self.0,
+                       sha256_of_onion: self.1
+               }
+       }
+}
+
+trait FailHTLCMessageName {
+       fn name() -> &'static str;
+}
+impl FailHTLCMessageName for msgs::UpdateFailHTLC {
+       fn name() -> &'static str {
+               "update_fail_htlc"
+       }
+}
+impl FailHTLCMessageName for msgs::UpdateFailMalformedHTLC {
+       fn name() -> &'static str {
+               "update_fail_malformed_htlc"
+       }
+}
+
 impl<SP: Deref> Channel<SP> where
        SP::Target: SignerProvider,
        <SP::Target as SignerProvider>::EcdsaSigner: WriteableEcdsaChannelSigner
@@ -2427,7 +2702,7 @@ 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;
@@ -2441,10 +2716,9 @@ 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
@@ -2497,7 +2771,7 @@ 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
@@ -2513,7 +2787,9 @@ impl<SP: Deref> Channel<SP> where
                                                        return UpdateFulfillFetch::DuplicateClaim {};
                                                }
                                        },
-                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } |
+                                               &HTLCUpdateAwaitingACK::FailMalformedHTLC { htlc_id, .. } =>
+                                       {
                                                if htlc_id_arg == htlc_id {
                                                        log_warn!(logger, "Have preimage and want to fulfill HTLC with pending failure against channel {}", &self.context.channel_id());
                                                        // TODO: We may actually be able to switch to a fulfill here, though its
@@ -2525,7 +2801,7 @@ 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,
                        });
@@ -2610,6 +2886,17 @@ impl<SP: Deref> Channel<SP> where
                        .map(|msg_opt| assert!(msg_opt.is_none(), "We forced holding cell?"))
        }
 
+       /// Used for failing back with [`msgs::UpdateFailMalformedHTLC`]. For now, this is used when we
+       /// want to fail blinded HTLCs where we are not the intro node.
+       ///
+       /// See [`Self::queue_fail_htlc`] for more info.
+       pub fn queue_fail_malformed_htlc<L: Deref>(
+               &mut self, htlc_id_arg: u64, failure_code: u16, sha256_of_onion: [u8; 32], logger: &L
+       ) -> Result<(), ChannelError> where L::Target: Logger {
+               self.fail_htlc(htlc_id_arg, (failure_code, sha256_of_onion), true, logger)
+                       .map(|msg_opt| assert!(msg_opt.is_none(), "We forced holding cell?"))
+       }
+
        /// We can only have one resolution per HTLC. In some cases around reconnect, we may fulfill
        /// an HTLC more than once or fulfill once and then attempt to fail after reconnect. We cannot,
        /// however, fail more than once as we wait for an upstream failure to be irrevocably committed
@@ -2618,12 +2905,13 @@ impl<SP: Deref> Channel<SP> where
        /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always
        /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be
        /// [`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) {
+       fn fail_htlc<L: Deref, E: FailHTLCContents + Clone>(
+               &mut self, htlc_id_arg: u64, err_packet: E, mut force_holding_cell: bool,
+               logger: &L
+       ) -> Result<Option<E::Message>, ChannelError> where L::Target: Logger {
+               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
@@ -2657,7 +2945,7 @@ 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;
                }
@@ -2673,7 +2961,9 @@ impl<SP: Deref> Channel<SP> where
                                                        return Ok(None);
                                                }
                                        },
-                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } |
+                                               &HTLCUpdateAwaitingACK::FailMalformedHTLC { htlc_id, .. } =>
+                                       {
                                                if htlc_id_arg == htlc_id {
                                                        debug_assert!(false, "Tried to fail an HTLC that was already failed");
                                                        return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
@@ -2683,127 +2973,28 @@ impl<SP: Deref> Channel<SP> where
                                }
                        }
                        log_trace!(logger, "Placing failure for HTLC ID {} in holding cell in channel {}.", htlc_id_arg, &self.context.channel_id());
-                       self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::FailHTLC {
-                               htlc_id: htlc_id_arg,
-                               err_packet,
-                       });
+                       self.context.holding_cell_htlc_updates.push(err_packet.to_htlc_update_awaiting_ack(htlc_id_arg));
                        return Ok(None);
                }
 
-               log_trace!(logger, "Failing HTLC ID {} back with a update_fail_htlc message in channel {}.", htlc_id_arg, &self.context.channel_id());
+               log_trace!(logger, "Failing HTLC ID {} back with {} message in channel {}.", htlc_id_arg,
+                       E::Message::name(), &self.context.channel_id());
                {
                        let htlc = &mut self.context.pending_inbound_htlcs[pending_idx];
-                       htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(err_packet.clone()));
+                       htlc.state = err_packet.clone().to_inbound_htlc_state();
                }
 
-               Ok(Some(msgs::UpdateFailHTLC {
-                       channel_id: self.context.channel_id(),
-                       htlc_id: htlc_id_arg,
-                       reason: err_packet
-               }))
+               Ok(Some(err_packet.to_message(htlc_id_arg, self.context.channel_id())))
        }
 
        // Message handlers:
-
-       /// Handles a funding_signed message from the remote end.
-       /// If this call is successful, broadcast the funding transaction (and not before!)
-       pub fn funding_signed<L: Deref>(
-               &mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L
-       ) -> Result<ChannelMonitor<<SP::Target as SignerProvider>::EcdsaSigner>, ChannelError>
-       where
-               L::Target: Logger
-       {
-               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 {
-                       return Err(ChannelError::Close("Received funding_signed in strange state!".to_owned()));
-               }
-               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
-                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
-               }
-
-               let funding_script = self.context.get_funding_redeemscript();
-
-               let counterparty_keys = self.context.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
-               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
-               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
-
-               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
-                       &self.context.channel_id(), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
-
-               let holder_signer = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx;
-               {
-                       let trusted_tx = initial_commitment_tx.trust();
-                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
-                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
-                       // They sign our commitment transaction, allowing us to broadcast the tx if we wish.
-                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.context.get_counterparty_pubkeys().funding_pubkey) {
-                               return Err(ChannelError::Close("Invalid funding_signed signature from peer".to_owned()));
-                       }
-               }
-
-               let holder_commitment_tx = HolderCommitmentTransaction::new(
-                       initial_commitment_tx,
-                       msg.signature,
-                       Vec::new(),
-                       &self.context.get_holder_pubkeys().funding_pubkey,
-                       self.context.counterparty_funding_pubkey()
-               );
-
-               self.context.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, Vec::new())
-                       .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
-
-
-               let funding_redeemscript = self.context.get_funding_redeemscript();
-               let funding_txo = self.context.get_funding_txo().unwrap();
-               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
-               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
-               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
-               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
-               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
-               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
-                                                         shutdown_script, self.context.get_holder_selected_contest_delay(),
-                                                         &self.context.destination_script, (funding_txo, funding_txo_script),
-                                                         &self.context.channel_transaction_parameters,
-                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
-                                                         obscure_factor,
-                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
-               channel_monitor.provide_initial_counterparty_commitment_tx(
-                       counterparty_initial_bitcoin_tx.txid, Vec::new(),
-                       self.context.cur_counterparty_commitment_transaction_number,
-                       self.context.counterparty_cur_commitment_point.unwrap(),
-                       counterparty_initial_commitment_tx.feerate_per_kw(),
-                       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!
-               if self.context.is_batch_funding() {
-                       self.context.channel_state = ChannelState::FundingSent as u32 | ChannelState::WaitingForBatch as u32;
-               } else {
-                       self.context.channel_state = ChannelState::FundingSent as u32;
-               }
-               self.context.cur_holder_commitment_transaction_number -= 1;
-               self.context.cur_counterparty_commitment_transaction_number -= 1;
-
-               log_info!(logger, "Received funding_signed from peer for channel {}", &self.context.channel_id());
-
-               let need_channel_ready = self.check_get_channel_ready(0).is_some();
-               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
-               Ok(channel_monitor)
-       }
-
        /// Updates the state of the channel to indicate that all channels in the batch have received
        /// funding_signed and persisted their monitors.
        /// The funding transaction is consequently allowed to be broadcast, and the channel can be
        /// 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
@@ -2817,7 +3008,7 @@ 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()));
                }
@@ -2831,24 +3022,31 @@ 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 =
@@ -2872,8 +3070,6 @@ 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;
@@ -2891,17 +3087,18 @@ 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 {
@@ -3036,7 +3233,7 @@ 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");
                        }
@@ -3086,10 +3283,10 @@ 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()));
                }
 
@@ -3097,10 +3294,10 @@ 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()));
                }
 
@@ -3109,10 +3306,10 @@ 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()));
                }
 
@@ -3123,13 +3320,13 @@ 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()));
                }
 
@@ -3242,7 +3439,7 @@ impl<SP: Deref> Channel<SP> where
                        self.context.counterparty_funding_pubkey()
                );
 
-               self.context.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, commitment_stats.preimages)
+               self.context.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, commitment_stats.outbound_htlc_preimages)
                        .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
 
                // Update state now that we've passed all the can-fail calls...
@@ -3304,11 +3501,11 @@ 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.
@@ -3324,7 +3521,7 @@ 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().
@@ -3350,8 +3547,7 @@ 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()) }
        }
@@ -3363,7 +3559,7 @@ 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());
@@ -3446,6 +3642,20 @@ impl<SP: Deref> Channel<SP> where
                                                        }
                                                }
                                        },
+                                       &HTLCUpdateAwaitingACK::FailMalformedHTLC { htlc_id, failure_code, sha256_of_onion } => {
+                                               match self.fail_htlc(htlc_id, (failure_code, sha256_of_onion), false, logger) {
+                                                       Ok(update_fail_malformed_opt) => {
+                                                               debug_assert!(update_fail_malformed_opt.is_some()); // See above comment
+                                                               update_fail_count += 1;
+                                                       },
+                                                       Err(e) => {
+                                                               if let ChannelError::Ignore(_) = e {}
+                                                               else {
+                                                                       panic!("Got a non-IgnoreError action trying to fail holding cell HTLC");
+                                                               }
+                                                       }
+                                               }
+                                       },
                                }
                        }
                        if update_add_count == 0 && update_fulfill_count == 0 && update_fail_count == 0 && self.context.holding_cell_update_fee.is_none() {
@@ -3484,13 +3694,13 @@ 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()));
                }
 
@@ -3502,7 +3712,7 @@ 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
@@ -3546,7 +3756,7 @@ 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);
@@ -3688,7 +3898,7 @@ 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 {
@@ -3810,7 +4020,7 @@ 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;
                }
 
@@ -3835,12 +4045,12 @@ 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(());
@@ -3902,7 +4112,7 @@ 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(())
        }
@@ -3929,7 +4139,7 @@ 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
@@ -3943,19 +4153,22 @@ 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;
                }
 
@@ -3986,7 +4199,7 @@ 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 {
@@ -4023,7 +4236,7 @@ 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)?;
@@ -4051,7 +4264,7 @@ impl<SP: Deref> Channel<SP> where
 
        /// Indicates that the signer may have some signatures for us, so we should retry if we're
        /// blocked.
-       #[allow(unused)]
+       #[cfg(async_signing)]
        pub fn signer_maybe_unblocked<L: Deref>(&mut self, logger: &L) -> SignerResumeUpdates where L::Target: Logger {
                let commitment_update = if self.context.signer_pending_commitment_update {
                        self.get_last_commitment_update_for_send(logger).ok()
@@ -4062,20 +4275,15 @@ impl<SP: Deref> Channel<SP> where
                let channel_ready = if funding_signed.is_some() {
                        self.check_get_channel_ready(0)
                } else { None };
-               let funding_created = if self.context.signer_pending_funding && self.context.is_outbound() {
-                       self.context.get_funding_created_msg(logger)
-               } else { None };
 
-               log_trace!(logger, "Signer unblocked with {} commitment_update, {} funding_signed, {} funding_created, and {} channel_ready",
+               log_trace!(logger, "Signer unblocked with {} commitment_update, {} funding_signed and {} channel_ready",
                        if commitment_update.is_some() { "a" } else { "no" },
                        if funding_signed.is_some() { "a" } else { "no" },
-                       if funding_created.is_some() { "a" } else { "no" },
                        if channel_ready.is_some() { "a" } else { "no" });
 
                SignerResumeUpdates {
                        commitment_update,
                        funding_signed,
-                       funding_created,
                        channel_ready,
                }
        }
@@ -4160,11 +4368,16 @@ impl<SP: Deref> Channel<SP> where
                        }
                        update
                } else {
-                       if !self.context.signer_pending_commitment_update {
-                               log_trace!(logger, "Commitment update awaiting signer: setting signer_pending_commitment_update");
-                               self.context.signer_pending_commitment_update = true;
+                       #[cfg(not(async_signing))] {
+                               panic!("Failed to get signature for new commitment state");
+                       }
+                       #[cfg(async_signing)] {
+                               if !self.context.signer_pending_commitment_update {
+                                       log_trace!(logger, "Commitment update awaiting signer: setting signer_pending_commitment_update");
+                                       self.context.signer_pending_commitment_update = true;
+                               }
+                               return Err(());
                        }
-                       return Err(());
                };
                Ok(msgs::CommitmentUpdate {
                        update_add_htlcs, update_fulfill_htlcs, update_fail_htlcs, update_fail_malformed_htlcs, update_fee,
@@ -4174,7 +4387,7 @@ 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,
@@ -4198,7 +4411,7 @@ 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.
@@ -4248,17 +4461,17 @@ 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()));
                                }
@@ -4290,7 +4503,7 @@ 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 {
@@ -4309,7 +4522,7 @@ 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();
                }
@@ -4345,7 +4558,7 @@ 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,
@@ -4532,10 +4745,10 @@ 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...
@@ -4546,7 +4759,7 @@ 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())));
@@ -4563,7 +4776,7 @@ 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,
@@ -4583,7 +4796,7 @@ 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 {
@@ -4619,7 +4832,7 @@ 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))
@@ -4653,10 +4866,10 @@ 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() {
@@ -4670,7 +4883,7 @@ 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));
                }
@@ -4706,9 +4919,11 @@ impl<SP: Deref> Channel<SP> where
                                        monitor_update: None,
                                        dropped_outbound_htlcs: Vec::new(),
                                        unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
+                                       channel_id: self.context.channel_id,
+                                       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)));
                        }
@@ -4734,8 +4949,10 @@ impl<SP: Deref> Channel<SP> where
                                                                monitor_update: None,
                                                                dropped_outbound_htlcs: Vec::new(),
                                                                unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
+                                                               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))
@@ -4860,7 +5077,7 @@ 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 {
@@ -4900,7 +5117,7 @@ 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.
@@ -4942,17 +5159,18 @@ 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.
@@ -4974,27 +5192,25 @@ 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 {
@@ -5031,35 +5247,36 @@ 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 {
@@ -5213,9 +5430,8 @@ 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
@@ -5242,8 +5458,8 @@ 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);
                }
 
@@ -5265,7 +5481,7 @@ impl<SP: Deref> Channel<SP> where
                        // larger. If we don't know that time has moved forward, we can just set it to the last
                        // time we saw and it will be ignored.
                        let best_time = self.context.update_time_counter;
-                       match self.do_best_block_updated(reorg_height, best_time, None::<(ChainHash, &&NodeSigner, &UserConfig)>, logger) {
+                       match self.do_best_block_updated(reorg_height, best_time, None::<(ChainHash, &&dyn NodeSigner, &UserConfig)>, logger) {
                                Ok((channel_ready, timed_out_htlcs, announcement_sigs)) => {
                                        assert!(channel_ready.is_none(), "We can't generate a funding with 0 confirmations?");
                                        assert!(timed_out_htlcs.is_empty(), "We can't have accepted HTLCs with a timeout before our funding confirmation?");
@@ -5341,7 +5557,7 @@ 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;
                }
@@ -5479,7 +5695,7 @@ 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
@@ -5515,7 +5731,7 @@ 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,
@@ -5577,7 +5793,10 @@ 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;
@@ -5600,7 +5819,7 @@ 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
@@ -5610,7 +5829,7 @@ 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" }
@@ -5717,7 +5936,7 @@ 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
        }
 
@@ -5771,8 +5990,12 @@ impl<SP: Deref> Channel<SP> where
                                                htlcs.push(htlc);
                                        }
 
-                                       let res = ecdsa.sign_counterparty_commitment(&commitment_stats.tx, commitment_stats.preimages, &self.context.secp_ctx)
-                                               .map_err(|_| ChannelError::Ignore("Failed to get signatures for new commitment_signed".to_owned()))?;
+                                       let res = ecdsa.sign_counterparty_commitment(
+                                                       &commitment_stats.tx,
+                                                       commitment_stats.inbound_htlc_preimages,
+                                                       commitment_stats.outbound_htlc_preimages,
+                                                       &self.context.secp_ctx,
+                                               ).map_err(|_| ChannelError::Ignore("Failed to get signatures for new commitment_signed".to_owned()))?;
                                        signature = res.0;
                                        htlc_signatures = res.1;
 
@@ -5847,44 +6070,32 @@ impl<SP: Deref> Channel<SP> where
 
        /// Begins the shutdown process, getting a message for the remote peer and returning all
        /// holding cell HTLCs for payment failure.
-       ///
-       /// May jump to the channel being fully shutdown (see [`Self::is_shutdown`]) in which case no
-       /// [`ChannelMonitorUpdate`] will be returned).
        pub fn get_shutdown(&mut self, signer_provider: &SP, their_features: &InitFeatures,
                target_feerate_sats_per_kw: Option<u32>, override_shutdown_script: Option<ShutdownScript>)
-       -> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>, Option<ShutdownResult>), APIError>
+       -> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), APIError>
        {
                for htlc in self.context.pending_outbound_htlcs.iter() {
                        if let OutboundHTLCState::LocalAnnounced(_) = htlc.state {
                                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 {
-                       chan_closed = true;
-               }
-
                let update_shutdown_script = match self.context.shutdown_scriptpubkey {
                        Some(_) => false,
-                       None if !chan_closed => {
+                       None => {
                                // use override shutdown script if provided
                                let shutdown_scriptpubkey = match override_shutdown_script {
                                        Some(script) => script,
@@ -5902,23 +6113,11 @@ impl<SP: Deref> Channel<SP> where
                                self.context.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
                                true
                        },
-                       None => false,
                };
 
                // 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 = ShutdownResult {
-                               monitor_update: None,
-                               dropped_outbound_htlcs: Vec::new(),
-                               unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
-                       };
-                       self.context.channel_state = ChannelState::ShutdownComplete as u32;
-                       Some(shutdown_result)
-               } else {
-                       self.context.channel_state |= ChannelState::LocalShutdownSent as u32;
-                       None
-               };
+               self.context.channel_state.set_local_shutdown_sent();
                self.context.update_time_counter += 1;
 
                let monitor_update = if update_shutdown_script {
@@ -5954,7 +6153,7 @@ impl<SP: Deref> Channel<SP> where
                debug_assert!(!self.is_shutdown() || monitor_update.is_none(),
                        "we can't both complete shutdown and return a monitor update");
 
-               Ok((shutdown, monitor_update, dropped_outbound_htlcs, shutdown_result))
+               Ok((shutdown, monitor_update, dropped_outbound_htlcs))
        }
 
        pub fn inflight_htlc_sources(&self) -> impl Iterator<Item=(&HTLCSource, &PaymentHash)> {
@@ -6065,7 +6264,7 @@ 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,
@@ -6182,6 +6381,38 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                })
        }
 
+       /// Only allowed after [`ChannelContext::channel_transaction_parameters`] is set.
+       fn get_funding_created_msg<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+               let signature = match &self.context.holder_signer {
+                       // TODO (taproot|arik): move match into calling method for Taproot
+                       ChannelSignerType::Ecdsa(ecdsa) => {
+                               ecdsa.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), Vec::new(), &self.context.secp_ctx)
+                                       .map(|(sig, _)| sig).ok()?
+                       },
+                       // TODO (taproot|arik)
+                       #[cfg(taproot)]
+                       _ => todo!()
+               };
+
+               if self.context.signer_pending_funding {
+                       log_trace!(logger, "Counterparty commitment signature ready for funding_created message: clearing signer_pending_funding");
+                       self.context.signer_pending_funding = false;
+               }
+
+               Some(msgs::FundingCreated {
+                       temporary_channel_id: self.context.temporary_channel_id.unwrap(),
+                       funding_txid: self.context.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().txid,
+                       funding_output_index: self.context.channel_transaction_parameters.funding_outpoint.as_ref().unwrap().index,
+                       signature,
+                       #[cfg(taproot)]
+                       partial_signature_with_nonce: None,
+                       #[cfg(taproot)]
+                       next_local_nonce: None,
+               })
+       }
+
        /// Updates channel state with knowledge of the funding transaction's txid/index, and generates
        /// a funding_created message for the remote peer.
        /// Panics if called at some time other than immediately after initial handshake, if called twice,
@@ -6189,12 +6420,15 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
        /// Note that channel_id changes during this call!
        /// Do NOT broadcast the funding transaction until after a successful funding_signed call!
        /// If an Err is returned, it is a ChannelError::Close.
-       pub fn get_funding_created<L: Deref>(mut self, funding_transaction: Transaction, funding_txo: OutPoint, is_batch_funding: bool, logger: &L)
-       -> Result<(Channel<SP>, Option<msgs::FundingCreated>), (Self, ChannelError)> where L::Target: Logger {
+       pub fn get_funding_created<L: Deref>(&mut self, funding_transaction: Transaction, funding_txo: OutPoint, is_batch_funding: bool, logger: &L)
+       -> Result<Option<msgs::FundingCreated>, (Self, ChannelError)> where L::Target: Logger {
                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) ||
@@ -6208,7 +6442,7 @@ 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.
@@ -6222,19 +6456,20 @@ impl<SP: Deref> OutboundV1Channel<SP> where SP::Target: SignerProvider {
                self.context.funding_transaction = Some(funding_transaction);
                self.context.is_batch_funding = Some(()).filter(|_| is_batch_funding);
 
-               let funding_created = self.context.get_funding_created_msg(logger);
+               let funding_created = self.get_funding_created_msg(logger);
                if funding_created.is_none() {
-                       if !self.context.signer_pending_funding {
-                               log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
-                               self.context.signer_pending_funding = true;
+                       #[cfg(not(async_signing))] {
+                               panic!("Failed to get signature for new funding creation");
+                       }
+                       #[cfg(async_signing)] {
+                               if !self.context.signer_pending_funding {
+                                       log_trace!(logger, "funding_created awaiting signer; setting signer_pending_funding");
+                                       self.context.signer_pending_funding = true;
+                               }
                        }
                }
 
-               let channel = Channel {
-                       context: self.context,
-               };
-
-               Ok((channel, funding_created))
+               Ok(funding_created)
        }
 
        fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures) -> ChannelTypeFeatures {
@@ -6269,7 +6504,14 @@ 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(());
@@ -6300,7 +6542,7 @@ 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");
                }
 
@@ -6346,7 +6588,7 @@ 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 {
@@ -6463,11 +6705,119 @@ 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(())
        }
+
+       /// Handles a funding_signed message from the remote end.
+       /// If this call is successful, broadcast the funding transaction (and not before!)
+       pub fn funding_signed<L: Deref>(
+               mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L
+       ) -> Result<(Channel<SP>, ChannelMonitor<<SP::Target as SignerProvider>::EcdsaSigner>), (OutboundV1Channel<SP>, ChannelError)>
+       where
+               L::Target: Logger
+       {
+               if !self.context.is_outbound() {
+                       return Err((self, ChannelError::Close("Received funding_signed for an inbound channel?".to_owned())));
+               }
+               if !matches!(self.context.channel_state, ChannelState::FundingNegotiated) {
+                       return Err((self, ChannelError::Close("Received funding_signed in strange state!".to_owned())));
+               }
+               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
+                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
+               }
+
+               let funding_script = self.context.get_funding_redeemscript();
+
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
+               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
+
+               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
+                       &self.context.channel_id(), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
+
+               let holder_signer = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx;
+               {
+                       let trusted_tx = initial_commitment_tx.trust();
+                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
+                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
+                       // They sign our commitment transaction, allowing us to broadcast the tx if we wish.
+                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.context.get_counterparty_pubkeys().funding_pubkey) {
+                               return Err((self, ChannelError::Close("Invalid funding_signed signature from peer".to_owned())));
+                       }
+               }
+
+               let holder_commitment_tx = HolderCommitmentTransaction::new(
+                       initial_commitment_tx,
+                       msg.signature,
+                       Vec::new(),
+                       &self.context.get_holder_pubkeys().funding_pubkey,
+                       self.context.counterparty_funding_pubkey()
+               );
+
+               let validated =
+                       self.context.holder_signer.as_ref().validate_holder_commitment(&holder_commitment_tx, Vec::new());
+               if validated.is_err() {
+                       return Err((self, ChannelError::Close("Failed to validate our commitment".to_owned())));
+               }
+
+               let funding_redeemscript = self.context.get_funding_redeemscript();
+               let funding_txo = self.context.get_funding_txo().unwrap();
+               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
+               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
+               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
+               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
+               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
+               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
+                                                         shutdown_script, self.context.get_holder_selected_contest_delay(),
+                                                         &self.context.destination_script, (funding_txo, funding_txo_script),
+                                                         &self.context.channel_transaction_parameters,
+                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
+                                                         obscure_factor,
+                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
+               channel_monitor.provide_initial_counterparty_commitment_tx(
+                       counterparty_initial_bitcoin_tx.txid, Vec::new(),
+                       self.context.cur_counterparty_commitment_transaction_number,
+                       self.context.counterparty_cur_commitment_point.unwrap(),
+                       counterparty_initial_commitment_tx.feerate_per_kw(),
+                       counterparty_initial_commitment_tx.to_broadcaster_value_sat(),
+                       counterparty_initial_commitment_tx.to_countersignatory_value_sat(), logger);
+
+               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::AwaitingChannelReady(AwaitingChannelReadyFlags::WAITING_FOR_BATCH);
+               } else {
+                       self.context.channel_state = ChannelState::AwaitingChannelReady(AwaitingChannelReadyFlags::new());
+               }
+               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.cur_counterparty_commitment_transaction_number -= 1;
+
+               log_info!(logger, "Received funding_signed from peer for channel {}", &self.context.channel_id());
+
+               let mut channel = Channel { context: self.context };
+
+               let need_channel_ready = channel.check_get_channel_ready(0).is_some();
+               channel.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
+               Ok((channel, channel_monitor))
+       }
+
+       /// Indicates that the signer may have some signatures for us, so we should retry if we're
+       /// blocked.
+       #[cfg(async_signing)]
+       pub fn signer_maybe_unblocked<L: Deref>(&mut self, logger: &L) -> Option<msgs::FundingCreated> where L::Target: Logger {
+               if self.context.signer_pending_funding && self.context.is_outbound() {
+                       log_trace!(logger, "Signer unblocked a funding_created");
+                       self.get_funding_created_msg(logger)
+               } else { None }
+       }
 }
 
 /// A not-yet-funded inbound (from counterparty) channel using V1 channel establishment.
@@ -6700,7 +7050,9 @@ 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,
 
@@ -6830,7 +7182,10 @@ 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 {
@@ -6910,7 +7265,10 @@ 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.
@@ -6955,7 +7313,7 @@ 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;
@@ -7073,7 +7431,13 @@ 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)?;
@@ -7130,7 +7494,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                let mut pending_outbound_blinding_points: Vec<Option<PublicKey>> = Vec::new();
 
                (self.context.pending_outbound_htlcs.len() as u64).write(writer)?;
-               for (idx, htlc) in self.context.pending_outbound_htlcs.iter().enumerate() {
+               for htlc in self.context.pending_outbound_htlcs.iter() {
                        htlc.htlc_id.write(writer)?;
                        htlc.amount_msat.write(writer)?;
                        htlc.cltv_expiry.write(writer)?;
@@ -7166,21 +7530,16 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                                        reason.write(writer)?;
                                }
                        }
-                       if let Some(skimmed_fee) = htlc.skimmed_fee_msat {
-                               if pending_outbound_skimmed_fees.is_empty() {
-                                       for _ in 0..idx { pending_outbound_skimmed_fees.push(None); }
-                               }
-                               pending_outbound_skimmed_fees.push(Some(skimmed_fee));
-                       } else if !pending_outbound_skimmed_fees.is_empty() {
-                               pending_outbound_skimmed_fees.push(None);
-                       }
+                       pending_outbound_skimmed_fees.push(htlc.skimmed_fee_msat);
                        pending_outbound_blinding_points.push(htlc.blinding_point);
                }
 
                let mut holding_cell_skimmed_fees: Vec<Option<u64>> = Vec::new();
                let mut holding_cell_blinding_points: Vec<Option<PublicKey>> = Vec::new();
+               // Vec of (htlc_id, failure_code, sha256_of_onion)
+               let mut malformed_htlcs: Vec<(u64, u16, [u8; 32])> = Vec::new();
                (self.context.holding_cell_htlc_updates.len() as u64).write(writer)?;
-               for (idx, update) in self.context.holding_cell_htlc_updates.iter().enumerate() {
+               for update in self.context.holding_cell_htlc_updates.iter() {
                        match update {
                                &HTLCUpdateAwaitingACK::AddHTLC {
                                        ref amount_msat, ref cltv_expiry, ref payment_hash, ref source, ref onion_routing_packet,
@@ -7193,13 +7552,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                                        source.write(writer)?;
                                        onion_routing_packet.write(writer)?;
 
-                                       if let Some(skimmed_fee) = skimmed_fee_msat {
-                                               if holding_cell_skimmed_fees.is_empty() {
-                                                       for _ in 0..idx { holding_cell_skimmed_fees.push(None); }
-                                               }
-                                               holding_cell_skimmed_fees.push(Some(skimmed_fee));
-                                       } else if !holding_cell_skimmed_fees.is_empty() { holding_cell_skimmed_fees.push(None); }
-
+                                       holding_cell_skimmed_fees.push(skimmed_fee_msat);
                                        holding_cell_blinding_points.push(blinding_point);
                                },
                                &HTLCUpdateAwaitingACK::ClaimHTLC { ref payment_preimage, ref htlc_id } => {
@@ -7212,6 +7565,18 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                                        htlc_id.write(writer)?;
                                        err_packet.write(writer)?;
                                }
+                               &HTLCUpdateAwaitingACK::FailMalformedHTLC {
+                                       htlc_id, failure_code, sha256_of_onion
+                               } => {
+                                       // We don't want to break downgrading by adding a new variant, so write a dummy
+                                       // `::FailHTLC` variant and write the real malformed error as an optional TLV.
+                                       malformed_htlcs.push((htlc_id, failure_code, sha256_of_onion));
+
+                                       let dummy_err_packet = msgs::OnionErrorPacket { data: Vec::new() };
+                                       2u8.write(writer)?;
+                                       htlc_id.write(writer)?;
+                                       dummy_err_packet.write(writer)?;
+                               }
                        }
                }
 
@@ -7372,6 +7737,7 @@ impl<SP: Deref> Writeable for Channel<SP> where SP::Target: SignerProvider {
                        (38, self.context.is_batch_funding, option),
                        (39, pending_outbound_blinding_points, optional_vec),
                        (41, holding_cell_blinding_points, optional_vec),
+                       (43, malformed_htlcs, optional_vec), // Added in 0.0.119
                });
 
                Ok(())
@@ -7406,7 +7772,7 @@ 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)?;
@@ -7662,6 +8028,8 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                let mut pending_outbound_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
                let mut holding_cell_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
 
+               let mut malformed_htlcs: Option<Vec<(u64, u16, [u8; 32])>> = None;
+
                read_tlv_fields!(reader, {
                        (0, announcement_sigs, option),
                        (1, minimum_depth, option),
@@ -7690,14 +8058,14 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        (38, is_batch_funding, option),
                        (39, pending_outbound_blinding_points_opt, optional_vec),
                        (41, holding_cell_blinding_points_opt, optional_vec),
+                       (43, malformed_htlcs, optional_vec), // Added in 0.0.119
                });
 
                let (channel_keys_id, holder_signer) = if let Some(channel_keys_id) = channel_keys_id {
                        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)
@@ -7785,6 +8153,22 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
                        if iter.next().is_some() { return Err(DecodeError::InvalidValue) }
                }
 
+               if let Some(malformed_htlcs) = malformed_htlcs {
+                       for (malformed_htlc_id, failure_code, sha256_of_onion) in malformed_htlcs {
+                               let htlc_idx = holding_cell_htlc_updates.iter().position(|htlc| {
+                                       if let HTLCUpdateAwaitingACK::FailHTLC { htlc_id, err_packet } = htlc {
+                                               let matches = *htlc_id == malformed_htlc_id;
+                                               if matches { debug_assert!(err_packet.data.is_empty()) }
+                                               matches
+                                       } else { false }
+                               }).ok_or(DecodeError::InvalidValue)?;
+                               let malformed_htlc = HTLCUpdateAwaitingACK::FailMalformedHTLC {
+                                       htlc_id: malformed_htlc_id, failure_code, sha256_of_onion
+                               };
+                               let _ = core::mem::replace(&mut holding_cell_htlc_updates[htlc_idx], malformed_htlc);
+                       }
+               }
+
                Ok(Channel {
                        context: ChannelContext {
                                user_id,
@@ -7919,11 +8303,12 @@ mod tests {
        use bitcoin::blockdata::transaction::{Transaction, TxOut};
        use bitcoin::blockdata::opcodes;
        use bitcoin::network::constants::Network;
+       use crate::ln::onion_utils::INVALID_ONION_BLINDING;
        use crate::ln::{PaymentHash, PaymentPreimage};
        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;
@@ -8096,11 +8481,12 @@ mod tests {
                        value: 10000000, script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
-               let (mut node_a_chan, funding_created_msg) = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
+               let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
                let (_, funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg.unwrap(), best_block, &&keys_provider, &&logger).map_err(|_| ()).unwrap();
 
                // Node B --> Node A: funding signed
-               let _ = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger).unwrap();
+               let res = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger);
+               let (mut node_a_chan, _) = if let Ok(res) = res { res } else { panic!(); };
 
                // Put some inbound and outbound HTLCs in A's channel.
                let htlc_amount_msat = 11_092_000; // put an amount below A's effective dust limit but above B's.
@@ -8224,11 +8610,12 @@ mod tests {
                        value: 10000000, script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
-               let (mut node_a_chan, funding_created_msg) = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
+               let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
                let (mut node_b_chan, funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg.unwrap(), best_block, &&keys_provider, &&logger).map_err(|_| ()).unwrap();
 
                // Node B --> Node A: funding signed
-               let _ = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger).unwrap();
+               let res = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger);
+               let (mut node_a_chan, _) = if let Ok(res) = res { res } else { panic!(); };
 
                // Now disconnect the two nodes and check that the commitment point in
                // Node B's channel_reestablish message is sane.
@@ -8412,11 +8799,12 @@ mod tests {
                        value: 10000000, script_pubkey: output_script.clone(),
                }]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
-               let (mut node_a_chan, funding_created_msg) = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
+               let funding_created_msg = node_a_chan.get_funding_created(tx.clone(), funding_outpoint, false, &&logger).map_err(|_| ()).unwrap();
                let (_, funding_signed_msg, _) = node_b_chan.funding_created(&funding_created_msg.unwrap(), best_block, &&keys_provider, &&logger).map_err(|_| ()).unwrap();
 
                // Node B --> Node A: funding signed
-               let _ = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger).unwrap();
+               let res = node_a_chan.funding_signed(&funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger);
+               let (mut node_a_chan, _) = if let Ok(res) = res { res } else { panic!(); };
 
                // Make sure that receiving a channel update will update the Channel as expected.
                let update = ChannelUpdate {
@@ -8452,8 +8840,9 @@ mod tests {
        }
 
        #[test]
-       fn blinding_point_ser() {
-               // Ensure that channel blinding points are (de)serialized properly.
+       fn blinding_point_skimmed_fee_malformed_ser() {
+               // Ensure that channel blinding points, skimmed fees, and malformed HTLCs are (de)serialized
+               // properly.
                let feeest = LowerBoundedFeeEstimator::new(&TestFeeEstimator{fee_est: 15000});
                let secp_ctx = Secp256k1::new();
                let seed = [42; 32];
@@ -8494,6 +8883,9 @@ mod tests {
                        if idx % 2 == 0 {
                                htlc.blinding_point = Some(test_utils::pubkey(42 + idx as u8));
                        }
+                       if idx % 3 == 0 {
+                               htlc.skimmed_fee_msat = Some(1);
+                       }
                }
                chan.context.pending_outbound_htlcs = pending_outbound_htlcs.clone();
 
@@ -8515,18 +8907,31 @@ mod tests {
                        payment_preimage: PaymentPreimage([42; 32]),
                        htlc_id: 0,
                };
-               let mut holding_cell_htlc_updates = Vec::with_capacity(10);
-               for i in 0..10 {
-                       if i % 3 == 0 {
+               let dummy_holding_cell_failed_htlc = |htlc_id| HTLCUpdateAwaitingACK::FailHTLC {
+                       htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42] }
+               };
+               let dummy_holding_cell_malformed_htlc = |htlc_id| HTLCUpdateAwaitingACK::FailMalformedHTLC {
+                       htlc_id, failure_code: INVALID_ONION_BLINDING, sha256_of_onion: [0; 32],
+               };
+               let mut holding_cell_htlc_updates = Vec::with_capacity(12);
+               for i in 0..12 {
+                       if i % 5 == 0 {
                                holding_cell_htlc_updates.push(dummy_holding_cell_add_htlc.clone());
-                       } else if i % 3 == 1 {
+                       } else if i % 5 == 1 {
                                holding_cell_htlc_updates.push(dummy_holding_cell_claim_htlc.clone());
-                       } else {
+                       } else if i % 5 == 2 {
                                let mut dummy_add = dummy_holding_cell_add_htlc.clone();
-                               if let HTLCUpdateAwaitingACK::AddHTLC { ref mut blinding_point, .. } = &mut dummy_add {
+                               if let HTLCUpdateAwaitingACK::AddHTLC {
+                                       ref mut blinding_point, ref mut skimmed_fee_msat, ..
+                               } = &mut dummy_add {
                                        *blinding_point = Some(test_utils::pubkey(42 + i));
+                                       *skimmed_fee_msat = Some(42);
                                } else { panic!() }
                                holding_cell_htlc_updates.push(dummy_add);
+                       } else if i % 5 == 3 {
+                               holding_cell_htlc_updates.push(dummy_holding_cell_malformed_htlc(i as u64));
+                       } else {
+                               holding_cell_htlc_updates.push(dummy_holding_cell_failed_htlc(i as u64));
                        }
                }
                chan.context.holding_cell_htlc_updates = holding_cell_htlc_updates.clone();
@@ -8541,7 +8946,7 @@ mod tests {
                assert_eq!(decoded_chan.context.holding_cell_htlc_updates, holding_cell_htlc_updates);
        }
 
-       #[cfg(feature = "_test_vectors")]
+       #[cfg(all(feature = "_test_vectors", not(feature = "grind_signatures")))]
        #[test]
        fn outbound_commitment_test() {
                use bitcoin::sighash;
@@ -8562,7 +8967,7 @@ mod tests {
 
                // Test vectors from BOLT 3 Appendices C and F (anchors):
                let feeest = TestFeeEstimator{fee_est: 15000};
-               let logger : Arc<Logger> = Arc::new(test_utils::TestLogger::new());
+               let logger : Arc<dyn Logger> = Arc::new(test_utils::TestLogger::new());
                let secp_ctx = Secp256k1::new();
 
                let mut signer = InMemorySigner::new(
@@ -9576,11 +9981,8 @@ mod tests {
                                },
                        ]};
                let funding_outpoint = OutPoint{ txid: tx.txid(), index: 0 };
-               let (mut node_a_chan, funding_created_msg) = node_a_chan.get_funding_created(
-                       tx.clone(),
-                       funding_outpoint,
-                       true,
-                       &&logger,
+               let funding_created_msg = node_a_chan.get_funding_created(
+                       tx.clone(), funding_outpoint, true, &&logger,
                ).map_err(|_| ()).unwrap();
                let (mut node_b_chan, funding_signed_msg, _) = node_b_chan.funding_created(
                        &funding_created_msg.unwrap(),
@@ -9598,12 +10000,10 @@ mod tests {
 
                // Receive funding_signed, but the channel will be configured to hold sending channel_ready and
                // broadcasting the funding transaction until the batch is ready.
-               let _ = node_a_chan.funding_signed(
-                       &funding_signed_msg.unwrap(),
-                       best_block,
-                       &&keys_provider,
-                       &&logger,
-               ).unwrap();
+               let res = node_a_chan.funding_signed(
+                       &funding_signed_msg.unwrap(), best_block, &&keys_provider, &&logger,
+               );
+               let (mut node_a_chan, _) = if let Ok(res) = res { res } else { panic!(); };
                let node_a_updates = node_a_chan.monitor_updating_restored(
                        &&logger,
                        &&keys_provider,
@@ -9615,11 +10015,7 @@ 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(
@@ -9632,18 +10028,12 @@ 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());
        }
 }