Drop ahash dependency in favor of core's SipHasher

tkaitchuck/aHash#196 bumped the MSRV of
`ahash` in a patch release, which makes it rather difficult for us
to have it as a dependency.

Further, it seems that `ahash` hasn't been particularly robust in
the past, notably
tkaitchuck/aHash#163 and
tkaitchuck/aHash#166.

Luckily, `core` provides `SipHasher` even on no-std (sadly its
SipHash-2-4 unlike the SipHash-1-3 used by the `DefaultHasher` in
`std`). Thus, we drop the `ahash` dependency entirely here and
simply wrap `SipHasher` for our `no-std` HashMaps.

.github/workflows/build.yml

@@ -110,7 +110,7 @@ jobs:
         run: |
           cd lightning
           RUSTFLAGS="--cfg=require_route_graph_test" cargo test
-          RUSTFLAGS="--cfg=require_route_graph_test" cargo test --features hashbrown,ahash
+          RUSTFLAGS="--cfg=require_route_graph_test" cargo test --features hashbrown
           cd ..
       - name: Run benchmarks on Rust ${{ matrix.toolchain }}
         run: |

bench/Cargo.toml

@@ -9,7 +9,7 @@ name = "bench"
 harness = false
 
 [features]
-hashbrown = ["lightning/hashbrown", "lightning/ahash"]
+hashbrown = ["lightning/hashbrown"]
 
 [dependencies]
 lightning = { path = "../lightning", features = ["_test_utils", "criterion"] }

ci/check-cfg-flags.py

@@ -13,7 +13,7 @@ def check_feature(feature):
         pass
     elif feature == "no-std":
         pass
-    elif feature == "ahash":
+    elif feature == "possiblyrandom":
         pass
     elif feature == "getrandom":
         pass

fuzz/Cargo.toml

@@ -22,7 +22,6 @@ lightning = { path = "../lightning", features = ["regex", "hashbrown", "_test_ut
 lightning-rapid-gossip-sync = { path = "../lightning-rapid-gossip-sync" }
 bitcoin = { version = "0.30.2", features = ["secp-lowmemory"] }
 hex = { package = "hex-conservative", version = "0.1.1", default-features = false }
-hashbrown = "0.13"
 
 afl = { version = "0.12", optional = true }
 honggfuzz = { version = "0.5", optional = true, default-features = false }

fuzz/src/chanmon_consistency.rs

@@ -51,6 +51,7 @@ use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath};
 use lightning::util::test_channel_signer::{TestChannelSigner, EnforcementState};
 use lightning::util::errors::APIError;
+use lightning::util::hash_tables::*;
 use lightning::util::logger::Logger;
 use lightning::util::config::UserConfig;
 use lightning::util::ser::{Readable, ReadableArgs, Writeable, Writer};
@@ -66,7 +67,6 @@ use bitcoin::secp256k1::schnorr;
 
 use std::mem;
 use std::cmp::{self, Ordering};
-use hashbrown::{HashSet, hash_map, HashMap};
 use std::sync::{Arc,Mutex};
 use std::sync::atomic;
 use std::io::Cursor;
@@ -157,7 +157,7 @@ impl TestChainMonitor {
 			logger,
 			keys,
 			persister,
-			latest_monitors: Mutex::new(HashMap::new()),
+			latest_monitors: Mutex::new(new_hash_map()),
 		}
 	}
 }
@@ -173,16 +173,13 @@ impl chain::Watch<TestChannelSigner> for TestChainMonitor {
 
 	fn update_channel(&self, funding_txo: OutPoint, update: &channelmonitor::ChannelMonitorUpdate) -> chain::ChannelMonitorUpdateStatus {
 		let mut map_lock = self.latest_monitors.lock().unwrap();
-		let mut map_entry = match map_lock.entry(funding_txo) {
-			hash_map::Entry::Occupied(entry) => entry,
-			hash_map::Entry::Vacant(_) => panic!("Didn't have monitor on update call"),
-		};
+		let map_entry = map_lock.get_mut(&funding_txo).expect("Didn't have monitor on update call");
 		let deserialized_monitor = <(BlockHash, channelmonitor::ChannelMonitor<TestChannelSigner>)>::
-			read(&mut Cursor::new(&map_entry.get().1), (&*self.keys, &*self.keys)).unwrap().1;
+			read(&mut Cursor::new(&map_entry.1), (&*self.keys, &*self.keys)).unwrap().1;
 		deserialized_monitor.update_monitor(update, &&TestBroadcaster{}, &&FuzzEstimator { ret_val: atomic::AtomicU32::new(253) }, &self.logger).unwrap();
 		let mut ser = VecWriter(Vec::new());
 		deserialized_monitor.write(&mut ser).unwrap();
-		map_entry.insert((update.update_id, ser.0));
+		*map_entry = (update.update_id, ser.0);
 		self.chain_monitor.update_channel(funding_txo, update)
 	}
 
@@ -467,7 +464,7 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 		($node_id: expr, $fee_estimator: expr) => { {
 			let logger: Arc<dyn Logger> = Arc::new(test_logger::TestLogger::new($node_id.to_string(), out.clone()));
 			let node_secret = SecretKey::from_slice(&[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, $node_id]).unwrap();
-			let keys_manager = Arc::new(KeyProvider { node_secret, rand_bytes_id: atomic::AtomicU32::new(0), enforcement_states: Mutex::new(HashMap::new()) });
+			let keys_manager = Arc::new(KeyProvider { node_secret, rand_bytes_id: atomic::AtomicU32::new(0), enforcement_states: Mutex::new(new_hash_map()) });
 			let monitor = Arc::new(TestChainMonitor::new(broadcast.clone(), logger.clone(), $fee_estimator.clone(),
 				Arc::new(TestPersister {
 					update_ret: Mutex::new(ChannelMonitorUpdateStatus::Completed)
@@ -508,13 +505,13 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 				config.manually_accept_inbound_channels = true;
 			}
 
-			let mut monitors = HashMap::new();
+			let mut monitors = new_hash_map();
 			let mut old_monitors = $old_monitors.latest_monitors.lock().unwrap();
 			for (outpoint, (update_id, monitor_ser)) in old_monitors.drain() {
 				monitors.insert(outpoint, <(BlockHash, ChannelMonitor<TestChannelSigner>)>::read(&mut Cursor::new(&monitor_ser), (&*$keys_manager, &*$keys_manager)).expect("Failed to read monitor").1);
 				chain_monitor.latest_monitors.lock().unwrap().insert(outpoint, (update_id, monitor_ser));
 			}
-			let mut monitor_refs = HashMap::new();
+			let mut monitor_refs = new_hash_map();
 			for (outpoint, monitor) in monitors.iter_mut() {
 				monitor_refs.insert(*outpoint, monitor);
 			}
@@ -981,7 +978,7 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 				// In case we get 256 payments we may have a hash collision, resulting in the
 				// second claim/fail call not finding the duplicate-hash HTLC, so we have to
 				// deduplicate the calls here.
-				let mut claim_set = HashSet::new();
+				let mut claim_set = new_hash_map();
 				let mut events = nodes[$node].get_and_clear_pending_events();
 				// Sort events so that PendingHTLCsForwardable get processed last. This avoids a
 				// case where we first process a PendingHTLCsForwardable, then claim/fail on a
@@ -1003,7 +1000,7 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 				for event in events.drain(..) {
 					match event {
 						events::Event::PaymentClaimable { payment_hash, .. } => {
-							if claim_set.insert(payment_hash.0) {
+							if claim_set.insert(payment_hash.0, ()).is_none() {
 								if $fail {
 									nodes[$node].fail_htlc_backwards(&payment_hash);
 								} else {

fuzz/src/full_stack.rs

@@ -49,6 +49,7 @@ use lightning::routing::gossip::{P2PGossipSync, NetworkGraph};
 use lightning::routing::utxo::UtxoLookup;
 use lightning::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters, Router};
 use lightning::util::config::{ChannelConfig, UserConfig};
+use lightning::util::hash_tables::*;
 use lightning::util::errors::APIError;
 use lightning::util::test_channel_signer::{TestChannelSigner, EnforcementState};
 use lightning::util::logger::Logger;
@@ -63,7 +64,6 @@ use bitcoin::secp256k1::ecdsa::{RecoverableSignature, Signature};
 use bitcoin::secp256k1::schnorr;
 
 use std::cell::RefCell;
-use hashbrown::{HashMap, hash_map};
 use std::convert::TryInto;
 use std::cmp;
 use std::sync::{Arc, Mutex};
@@ -229,7 +229,7 @@ impl<'a> MoneyLossDetector<'a> {
 
 			peers,
 			funding_txn: Vec::new(),
-			txids_confirmed: HashMap::new(),
+			txids_confirmed: new_hash_map(),
 			header_hashes: vec![(genesis_block(Network::Bitcoin).block_hash(), 0)],
 			height: 0,
 			max_height: 0,
@@ -241,13 +241,10 @@ impl<'a> MoneyLossDetector<'a> {
 		let mut txdata = Vec::with_capacity(all_txn.len());
 		for (idx, tx) in all_txn.iter().enumerate() {
 			let txid = tx.txid();
-			match self.txids_confirmed.entry(txid) {
-				hash_map::Entry::Vacant(e) => {
-					e.insert(self.height);
-					txdata.push((idx + 1, tx));
-				},
-				_ => {},
-			}
+			self.txids_confirmed.entry(txid).or_insert_with(|| {
+				txdata.push((idx + 1, tx));
+				self.height
+			});
 		}
 
 		self.blocks_connected += 1;
@@ -489,7 +486,7 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger>) {
 		node_secret: our_network_key.clone(),
 		inbound_payment_key: KeyMaterial(inbound_payment_key.try_into().unwrap()),
 		counter: AtomicU64::new(0),
-		signer_state: RefCell::new(HashMap::new())
+		signer_state: RefCell::new(new_hash_map())
 	});
 	let network = Network::Bitcoin;
 	let best_block_timestamp = genesis_block(network).header.time;
@@ -518,7 +515,7 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger>) {
 	let mut intercepted_htlcs: Vec<InterceptId> = Vec::new();
 	let mut payments_sent: u16 = 0;
 	let mut pending_funding_generation: Vec<(ChannelId, PublicKey, u64, ScriptBuf)> = Vec::new();
-	let mut pending_funding_signatures = HashMap::new();
+	let mut pending_funding_signatures = new_hash_map();
 
 	loop {
 		match get_slice!(1)[0] {

fuzz/src/indexedmap.rs

@@ -9,7 +9,7 @@
 
 use lightning::util::indexed_map::{IndexedMap, self};
 use std::collections::{BTreeMap, btree_map};
-use hashbrown::HashSet;
+use lightning::util::hash_tables::*;
 
 use crate::utils::test_logger;
 
@@ -80,23 +80,23 @@ fn check_eq(btree: &BTreeMap<u8, u8>, mut indexed: IndexedMap<u8, u8>) {
 		}
 	}
 
-	let mut key_set = HashSet::with_capacity(256);
+	let mut key_set = hash_map_with_capacity(1024);
 	for k in indexed.unordered_keys() {
-		assert!(key_set.insert(*k));
+		assert!(key_set.insert(*k, ()).is_none());
 		assert!(btree.contains_key(k));
 	}
 	assert_eq!(key_set.len(), btree.len());
 
 	key_set.clear();
 	for (k, v) in indexed.unordered_iter() {
-		assert!(key_set.insert(*k));
+		assert!(key_set.insert(*k, ()).is_none());
 		assert_eq!(btree.get(k).unwrap(), v);
 	}
 	assert_eq!(key_set.len(), btree.len());
 
 	key_set.clear();
 	for (k, v) in indexed_clone.unordered_iter_mut() {
-		assert!(key_set.insert(*k));
+		assert!(key_set.insert(*k, ()).is_none());
 		assert_eq!(btree.get(k).unwrap(), v);
 	}
 	assert_eq!(key_set.len(), btree.len());

fuzz/src/router.rs

@@ -23,6 +23,7 @@ use lightning::routing::utxo::{UtxoFuture, UtxoLookup, UtxoLookupError, UtxoResu
 use lightning::routing::router::{find_route, PaymentParameters, RouteHint, RouteHintHop, RouteParameters};
 use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters};
 use lightning::util::config::UserConfig;
+use lightning::util::hash_tables::*;
 use lightning::util::ser::Readable;
 
 use bitcoin::hashes::Hash;
@@ -32,7 +33,6 @@ use bitcoin::network::constants::Network;
 use crate::utils::test_logger;
 
 use std::convert::TryInto;
-use hashbrown::HashSet;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
@@ -198,7 +198,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 		net_graph: &net_graph,
 	};
 
-	let mut node_pks = HashSet::new();
+	let mut node_pks = new_hash_map();
 	let mut scid = 42;
 
 	macro_rules! first_hops {
@@ -208,7 +208,8 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 				count => {
 					for _ in 0..count {
 						scid += 1;
-						let rnid = node_pks.iter().skip(u16::from_be_bytes(get_slice!(2).try_into().unwrap()) as usize % node_pks.len()).next().unwrap();
+						let (rnid, _) =
+							node_pks.iter().skip(u16::from_be_bytes(get_slice!(2).try_into().unwrap()) as usize % node_pks.len()).next().unwrap();
 						let capacity = u64::from_be_bytes(get_slice!(8).try_into().unwrap());
 						$first_hops_vec.push(ChannelDetails {
 							channel_id: ChannelId::new_zero(),
@@ -257,7 +258,8 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 			let count = get_slice!(1)[0];
 			for _ in 0..count {
 				scid += 1;
-				let rnid = node_pks.iter().skip(slice_to_be16(get_slice!(2))as usize % node_pks.len()).next().unwrap();
+				let (rnid, _) =
+					node_pks.iter().skip(slice_to_be16(get_slice!(2)) as usize % node_pks.len()).next().unwrap();
 				$last_hops.push(RouteHint(vec![RouteHintHop {
 					src_node_id: *rnid,
 					short_channel_id: scid,
@@ -277,7 +279,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 		($first_hops: expr, $node_pks: expr, $route_params: expr) => {
 			let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &net_graph, &logger);
 			let random_seed_bytes: [u8; 32] = [get_slice!(1)[0]; 32];
-			for target in $node_pks {
+			for (target, ()) in $node_pks {
 				let final_value_msat = slice_to_be64(get_slice!(8));
 				let final_cltv_expiry_delta = slice_to_be32(get_slice!(4));
 				let route_params = $route_params(final_value_msat, final_cltv_expiry_delta, target);
@@ -297,20 +299,20 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 					return;
 				}
 				let msg = decode_msg_with_len16!(msgs::UnsignedNodeAnnouncement, 288);
-				node_pks.insert(get_pubkey_from_node_id!(msg.node_id));
+				node_pks.insert(get_pubkey_from_node_id!(msg.node_id), ());
 				let _ = net_graph.update_node_from_unsigned_announcement(&msg);
 			},
 			1 => {
 				let msg = decode_msg_with_len16!(msgs::UnsignedChannelAnnouncement, 32+8+33*4);
-				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_1));
-				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_2));
+				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_1), ());
+				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_2), ());
 				let _ = net_graph.update_channel_from_unsigned_announcement::
 					<&FuzzChainSource<'_, '_, Out>>(&msg, &None);
 			},
 			2 => {
 				let msg = decode_msg_with_len16!(msgs::UnsignedChannelAnnouncement, 32+8+33*4);
-				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_1));
-				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_2));
+				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_1), ());
+				node_pks.insert(get_pubkey_from_node_id!(msg.node_id_2), ());
 				let _ = net_graph.update_channel_from_unsigned_announcement(&msg, &Some(&chain_source));
 			},
 			3 => {
@@ -367,7 +369,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
 				}).collect();
 				let mut features = Bolt12InvoiceFeatures::empty();
 				features.set_basic_mpp_optional();
-				find_routes!(first_hops, vec![dummy_pk].iter(), |final_amt, _, _| {
+				find_routes!(first_hops, [(dummy_pk, ())].iter(), |final_amt, _, _| {
 					RouteParameters::from_payment_params_and_value(PaymentParameters::blinded(last_hops.clone())
 						.with_bolt12_features(features.clone()).unwrap(),
 					final_amt)

lightning/Cargo.toml

@@ -31,7 +31,7 @@ unsafe_revoked_tx_signing = []
 # Override signing to not include randomness when generating signatures for test vectors.
 _test_vectors = []
 
-no-std = ["hashbrown", "ahash", "bitcoin/no-std", "core2/alloc", "libm"]
+no-std = ["hashbrown", "possiblyrandom", "bitcoin/no-std", "core2/alloc", "libm"]
 std = ["bitcoin/std"]
 
 # Generates low-r bitcoin signatures, which saves 1 byte in 50% of the cases
@@ -42,25 +42,15 @@ default = ["std", "grind_signatures"]
 [dependencies]
 bitcoin = { version = "0.30.2", default-features = false, features = ["secp-recovery"] }
 
-hashbrown = { version = "0.13", optional = true }
-ahash = { version = "0.8", optional = true, default-features = false }
+hashbrown = { version = "0.13", optional = true, default-features = false }
+possiblyrandom = { version = "0.1", optional = true, default-features = false }
 hex = { package = "hex-conservative", version = "0.1.1", default-features = false }
 regex = { version = "1.5.6", optional = true }
 backtrace = { version = "0.3", optional = true }
 
 core2 = { version = "0.3.0", optional = true, default-features = false }
 libm = { version = "0.2", optional = true, default-features = false }
 
-# Because ahash no longer (kinda poorly) does it for us, (roughly) list out the targets that
-# getrandom supports and turn on ahash's `runtime-rng` feature for them.
-[target.'cfg(not(any(target_os = "unknown", target_os = "none")))'.dependencies]
-ahash = { version = "0.8", optional = true, default-features = false, features = ["runtime-rng"] }
-
-# Not sure what target_os gets set to for sgx, so to be safe always enable runtime-rng for x86_64
-# platforms (assuming LDK isn't being used on embedded x86-64 running directly on metal).
-[target.'cfg(target_arch = "x86_64")'.dependencies]
-ahash = { version = "0.8", optional = true, default-features = false, features = ["runtime-rng"] }
-
 [dev-dependencies]
 regex = "1.5.6"