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Enforce compile-time check for flag getters and setters
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This ensures that we cannot define or use flag getters/setters on
`ChannelState` variants in which said flag is not valid.
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@wpaulino
wpaulino committed Jan 29, 2024
1 parent 9ab7a48 commit 25ec63f
Showing 1 changed file with 49 additions and 40 deletions.
89 changes: 49 additions & 40 deletions lightning/src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -267,7 +267,7 @@ enum HTLCUpdateAwaitingACK {
}

macro_rules! define_state_flags {
($flag_type_doc: expr, $flag_type: ident, [$(($flag_doc: expr, $flag: ident, $value: expr)),+], $extra_flags: expr) => {
($flag_type_doc: expr, $flag_type: ident, [$(($flag_doc: expr, $flag: ident, $value: expr, $get: ident, $set: ident, $clear: ident)),+], $extra_flags: expr) => {
#[doc = $flag_type_doc]
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq)]
struct $flag_type(u32);
Expand Down Expand Up @@ -296,7 +296,6 @@ macro_rules! define_state_flags {

#[allow(unused)]
fn is_empty(&self) -> bool { self.0 == 0 }

#[allow(unused)]
fn is_set(&self, flag: Self) -> bool { *self & flag == flag }
#[allow(unused)]
Expand All @@ -305,10 +304,10 @@ macro_rules! define_state_flags {
fn clear(&mut self, flag: Self) -> Self { self.0 &= !flag.0; *self }
}

impl core::ops::Not for $flag_type {
type Output = Self;
fn not(self) -> Self::Output { Self(!self.0) }
}
$(
define_state_flags!($flag_type, Self::$flag, $get, $set, $clear);
)*

impl core::ops::BitOr for $flag_type {
type Output = Self;
fn bitor(self, rhs: Self) -> Self::Output { Self(self.0 | rhs.0) }
Expand Down Expand Up @@ -339,6 +338,16 @@ macro_rules! define_state_flags {
};
($flag_type_doc: expr, FUNDED_STATE, $flag_type: ident, $flags: tt) => {
define_state_flags!($flag_type_doc, $flag_type, $flags, FundedStateFlags::ALL.0);

define_state_flags!($flag_type, FundedStateFlags::PEER_DISCONNECTED,
is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected);
define_state_flags!($flag_type, FundedStateFlags::MONITOR_UPDATE_IN_PROGRESS,
is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress);
define_state_flags!($flag_type, FundedStateFlags::REMOTE_SHUTDOWN_SENT,
is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent);
define_state_flags!($flag_type, FundedStateFlags::LOCAL_SHUTDOWN_SENT,
is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent);

impl core::ops::BitOr<FundedStateFlags> for $flag_type {
type Output = Self;
fn bitor(self, rhs: FundedStateFlags) -> Self::Output { Self(self.0 | rhs.0) }
Expand Down Expand Up @@ -385,25 +394,29 @@ 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),
until after we've done a `channel_reestablish` dance.", PEER_DISCONNECTED, state_flags::PEER_DISCONNECTED,
is_peer_disconnected, set_peer_disconnected, clear_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),
complete it.", MONITOR_UPDATE_IN_PROGRESS, state_flags::MONITOR_UPDATE_IN_PROGRESS,
is_monitor_update_in_progress, set_monitor_update_in_progress, clear_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),
message when possible.", REMOTE_SHUTDOWN_SENT, state_flags::REMOTE_SHUTDOWN_SENT,
is_remote_shutdown_sent, set_remote_shutdown_sent, clear_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)
the channel.", LOCAL_SHUTDOWN_SENT, state_flags::LOCAL_SHUTDOWN_SENT,
is_local_shutdown_sent, set_local_shutdown_sent, clear_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),
OUR_INIT_SENT, state_flags::OUR_INIT_SENT, is_our_init_sent, set_our_init_sent, clear_our_init_sent),
("Indicates we have received their `open_channel`/`accept_channel` message.",
THEIR_INIT_SENT, state_flags::THEIR_INIT_SENT)
THEIR_INIT_SENT, state_flags::THEIR_INIT_SENT, is_their_init_sent, set_their_init_sent, clear_their_init_sent)
]
);

Expand All @@ -412,13 +425,16 @@ define_state_flags!(
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),
THEIR_CHANNEL_READY, state_flags::THEIR_CHANNEL_READY,
is_their_channel_ready, set_their_channel_ready, clear_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),
OUR_CHANNEL_READY, state_flags::OUR_CHANNEL_READY,
is_our_channel_ready, set_our_channel_ready, clear_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)
their monitors persisted.", WAITING_FOR_BATCH, state_flags::WAITING_FOR_BATCH,
is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch)
]
);

Expand All @@ -429,7 +445,8 @@ define_state_flags!(
`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)
AWAITING_REMOTE_REVOKE, state_flags::AWAITING_REMOTE_REVOKE,
is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke)
]
);

Expand All @@ -455,12 +472,12 @@ enum ChannelState {
}

macro_rules! impl_state_flag {
($get: ident, $set: ident, $clear: ident, $state_flag: expr, [$($state: ident),+]) => {
($get: ident, $set: ident, $clear: ident, [$($state: ident),+]) => {
#[allow(unused)]
fn $get(&self) -> bool {
match self {
$(
ChannelState::$state(flags) => flags.is_set($state_flag.into()),
ChannelState::$state(flags) => flags.$get(),
)*
_ => false,
}
Expand All @@ -469,7 +486,7 @@ macro_rules! impl_state_flag {
fn $set(&mut self) {
match self {
$(
ChannelState::$state(flags) => *flags |= $state_flag,
ChannelState::$state(flags) => flags.$set(),
)*
_ => debug_assert!(false, "Attempted to set flag on unexpected ChannelState"),
}
Expand All @@ -478,17 +495,17 @@ macro_rules! impl_state_flag {
fn $clear(&mut self) {
match self {
$(
ChannelState::$state(flags) => *flags &= !($state_flag),
ChannelState::$state(flags) => { let _ = flags.$clear(); },
)*
_ => debug_assert!(false, "Attempted to clear flag on unexpected ChannelState"),
}
}
};
($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, $clear: ident, FUNDED_STATES) => {
impl_state_flag!($get, $set, $clear, [AwaitingChannelReady, ChannelReady]);
};
($get: ident, $set: ident, $clear: ident, $state_flag: expr, $state: ident) => {
impl_state_flag!($get, $set, $clear, $state_flag, [$state]);
($get: ident, $set: ident, $clear: ident, $state: ident) => {
impl_state_flag!($get, $set, $clear, [$state]);
};
}

Expand Down Expand Up @@ -552,22 +569,14 @@ impl ChannelState {
}
}

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);
impl_state_flag!(is_peer_disconnected, set_peer_disconnected, clear_peer_disconnected, FUNDED_STATES);
impl_state_flag!(is_monitor_update_in_progress, set_monitor_update_in_progress, clear_monitor_update_in_progress, FUNDED_STATES);
impl_state_flag!(is_local_shutdown_sent, set_local_shutdown_sent, clear_local_shutdown_sent, FUNDED_STATES);
impl_state_flag!(is_remote_shutdown_sent, set_remote_shutdown_sent, clear_remote_shutdown_sent, FUNDED_STATES);
impl_state_flag!(is_our_channel_ready, set_our_channel_ready, clear_our_channel_ready, AwaitingChannelReady);
impl_state_flag!(is_their_channel_ready, set_their_channel_ready, clear_their_channel_ready, AwaitingChannelReady);
impl_state_flag!(is_waiting_for_batch, set_waiting_for_batch, clear_waiting_for_batch, AwaitingChannelReady);
impl_state_flag!(is_awaiting_remote_revoke, set_awaiting_remote_revoke, clear_awaiting_remote_revoke, ChannelReady);
}

pub const INITIAL_COMMITMENT_NUMBER: u64 = (1 << 48) - 1;
Expand Down

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