Add safe_sum and use it in state_processing (#1620 )

## Issue Addressed Closes #1098 ## Proposed Changes Add a `SafeArithIter` trait with a `safe_sum` method, and use it in `state_processing`. This seems to be the only place in `consensus` where it is relevant -- i.e. where we were using `sum` and the integer_arith lint is enabled. ## Additional Info This PR doesn't include any Clippy linting to prevent `sum` from being called. It seems there is no existing Clippy lint that suits our purpose, but I'm going to look into that and maybe schedule writing one as a lower-priority task. This theoretically _is_ a consensus breaking change, but it shouldn't impact Medalla (or any other testnet) because `slashings` shouldn't overflow!
Update BLST, add force-adx support (#1595 )
2026-03-05 09:41:42 +00:00 · 2020-09-22 05:40:04 +00:00 · 2020-09-22 05:40:02 +00:00 · 2020-09-22 04:45:15 +00:00 · 2020-09-22 02:06:10 +00:00 · 2020-09-22 01:12:36 +00:00
34 changed files with 631 additions and 256 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,7 +2,7 @@
 # It is not intended for manual editing.
 [[package]]
 name = "account_manager"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "account_utils",
 "bls",
@@ -370,7 +370,7 @@ dependencies = [

 [[package]]
 name = "beacon_node"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "beacon_chain",
 "clap",
@@ -386,7 +386,7 @@ dependencies = [
 "exit-future",
 "futures 0.3.5",
 "genesis",
- "hyper 0.13.7",
+ "hyper 0.13.8",
 "lighthouse_version",
 "logging",
 "node_test_rig",
@@ -525,7 +525,7 @@ dependencies = [
 [[package]]
 name = "blst"
 version = "0.1.1"
-source = "git+https://github.com/sigp/blst.git?rev=284f7059642851c760a09fb1708bcb59c7ca323c#284f7059642851c760a09fb1708bcb59c7ca323c"
+source = "git+https://github.com/supranational/blst.git?rev=a8398ed284b0d78858302ad1ceb25a80e7bbe535#a8398ed284b0d78858302ad1ceb25a80e7bbe535"
 dependencies = [
 "cc",
 "glob",
@@ -534,7 +534,7 @@ dependencies = [

 [[package]]
 name = "boot_node"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "beacon_node",
 "clap",
@@ -777,7 +777,7 @@ dependencies = [
 "sloggers",
 "slot_clock",
 "store",
- "time 0.2.20",
+ "time 0.2.21",
 "timer",
 "tokio 0.2.22",
 "toml",
@@ -1292,9 +1292,9 @@ dependencies = [

 [[package]]
 name = "ed25519-dalek"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53d2e93f837d749c16d118e7ddf7a4dfd0ac8f452cf51e46e9348824e5ef6851"
+checksum = "c762bae6dcaf24c4c84667b8579785430908723d5c889f469d76a41d59cc7a9d"
 dependencies = [
 "curve25519-dalek 3.0.0",
 "ed25519",
@@ -2146,9 +2146,9 @@ dependencies = [

 [[package]]
 name = "hermit-abi"
-version = "0.1.15"
+version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
+checksum = "4c30f6d0bc6b00693347368a67d41b58f2fb851215ff1da49e90fe2c5c667151"
 dependencies = [
 "libc",
 ]
@@ -2262,6 +2262,12 @@ version = "1.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cd179ae861f0c2e53da70d892f5f3029f9594be0c41dc5269cd371691b1dc2f9"

+[[package]]
+name = "httpdate"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "494b4d60369511e7dea41cf646832512a94e542f68bb9c49e54518e0f468eb47"
+
 [[package]]
 name = "humantime"
 version = "1.3.0"
@@ -2322,9 +2328,9 @@ dependencies = [

 [[package]]
 name = "hyper"
-version = "0.13.7"
+version = "0.13.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3e68a8dd9716185d9e64ea473ea6ef63529252e3e27623295a0378a19665d5eb"
+checksum = "2f3afcfae8af5ad0576a31e768415edb627824129e8e5a29b8bfccb2f234e835"
 dependencies = [
 "bytes 0.5.6",
 "futures-channel",
@@ -2334,10 +2340,10 @@ dependencies = [
 "http 0.2.1",
 "http-body 0.3.1",
 "httparse",
+ "httpdate",
 "itoa",
 "pin-project",
 "socket2",
- "time 0.1.44",
 "tokio 0.2.22",
 "tower-service",
 "tracing",
@@ -2364,7 +2370,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d979acc56dcb5b8dddba3917601745e877576475aa046df3226eabdecef78eed"
 dependencies = [
 "bytes 0.5.6",
- "hyper 0.13.7",
+ "hyper 0.13.8",
 "native-tls",
 "tokio 0.2.22",
 "tokio-tls 0.3.1",
@@ -2431,9 +2437,12 @@ dependencies = [

 [[package]]
 name = "instant"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b141fdc7836c525d4d594027d318c84161ca17aaf8113ab1f81ab93ae897485"
+checksum = "63312a18f7ea8760cdd0a7c5aac1a619752a246b833545e3e36d1f81f7cd9e66"
+dependencies = [
+ "cfg-if",
+]

 [[package]]
 name = "int_to_bytes"
@@ -2553,7 +2562,7 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"

 [[package]]
 name = "lcli"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "bls",
 "clap",
@@ -2585,9 +2594,9 @@ dependencies = [

 [[package]]
 name = "leveldb"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5a2fa830c44ac4762564389a7efe22688a469c8d7b71dd11da2e35c33ae96c2"
+checksum = "32651baaaa5596b3a6e0bee625e73fd0334c167db0ea5ac68750ef9a629a2d6a"
 dependencies = [
 "db-key",
 "leveldb-sys",
@@ -2596,8 +2605,9 @@ dependencies = [

 [[package]]
 name = "leveldb-sys"
-version = "2.0.6"
-source = "git+https://github.com/michaelsproul/leveldb-sys?branch=v2.0.6-cmake#e784dba085921bad187ff74b3418c539914a02ff"
+version = "2.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76c44b9b785ca705d58190ebd432a4e7edb900eadf236ff966d7d1307e482e87"
 dependencies = [
 "cmake",
 "libc",
@@ -2911,7 +2921,7 @@ dependencies = [

 [[package]]
 name = "lighthouse"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "account_manager",
 "account_utils",
@@ -3071,9 +3081,9 @@ checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"

 [[package]]
 name = "memoffset"
-version = "0.5.5"
+version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c198b026e1bbf08a937e94c6c60f9ec4a2267f5b0d2eec9c1b21b061ce2be55f"
+checksum = "043175f069eda7b85febe4a74abbaeff828d9f8b448515d3151a14a3542811aa"
 dependencies = [
 "autocfg 1.0.1",
 ]
@@ -4108,9 +4118,9 @@ dependencies = [

 [[package]]
 name = "rayon-core"
-version = "1.8.0"
+version = "1.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91739a34c4355b5434ce54c9086c5895604a9c278586d1f1aa95e04f66b525a0"
+checksum = "e8c4fec834fb6e6d2dd5eece3c7b432a52f0ba887cf40e595190c4107edc08bf"
 dependencies = [
 "crossbeam-channel",
 "crossbeam-deque",
@@ -4212,7 +4222,7 @@ dependencies = [
 "futures-util",
 "http 0.2.1",
 "http-body 0.3.1",
- "hyper 0.13.7",
+ "hyper 0.13.8",
 "hyper-tls 0.4.3",
 "ipnet",
 "js-sys",
@@ -4251,7 +4261,7 @@ dependencies = [
 "futures 0.3.5",
 "hex 0.4.2",
 "http 0.2.1",
- "hyper 0.13.7",
+ "hyper 0.13.8",
 "itertools 0.9.0",
 "lazy_static",
 "lighthouse_metrics",
@@ -4288,7 +4298,7 @@ dependencies = [
 "eth2_hashing",
 "eth2_ssz",
 "eth2_ssz_derive",
- "hyper 0.13.7",
+ "hyper 0.13.8",
 "procinfo",
 "psutil",
 "rayon",
@@ -4915,9 +4925,9 @@ checksum = "fbee7696b84bbf3d89a1c2eccff0850e3047ed46bfcd2e92c29a2d074d57e252"

 [[package]]
 name = "snafu"
-version = "0.6.8"
+version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7f5aed652511f5c9123cf2afbe9c244c29db6effa2abb05c866e965c82405ce"
+checksum = "9c4e6046e4691afe918fd1b603fd6e515bcda5388a1092a9edbada307d159f09"
 dependencies = [
 "doc-comment",
 "snafu-derive",
@@ -4925,9 +4935,9 @@ dependencies = [

 [[package]]
 name = "snafu-derive"
-version = "0.6.8"
+version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebf8f7d5720104a9df0f7076a8682024e958bba0fe9848767bb44f251f3648e9"
+checksum = "7073448732a89f2f3e6581989106067f403d378faeafb4a50812eb814170d3e5"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -5309,9 +5319,9 @@ dependencies = [

 [[package]]
 name = "time"
-version = "0.2.20"
+version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0d4953c513c9bf1b97e9cdd83f11d60c4b0a83462880a360d80d96953a953fee"
+checksum = "2c2e31fb28e2a9f01f5ed6901b066c1ba2333c04b64dc61254142bafcb3feb2c"
 dependencies = [
 "const_fn",
 "libc",
@@ -6026,7 +6036,7 @@ dependencies = [

 [[package]]
 name = "validator_client"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
 "account_utils",
 "bls",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -79,4 +79,3 @@ eth2_ssz = { path = "consensus/ssz" }
 eth2_ssz_derive = { path = "consensus/ssz_derive" }
 eth2_ssz_types = { path = "consensus/ssz_types" }
 eth2_hashing = { path = "crypto/eth2_hashing" }
-leveldb-sys = { git = "https://github.com/michaelsproul/leveldb-sys", branch = "v2.0.6-cmake" }
--- a/account_manager/Cargo.toml
+++ b/account_manager/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "account_manager"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Paul Hauner <paul@paulhauner.com>", "Luke Anderson <luke@sigmaprime.io>"]
 edition = "2018"

--- a/beacon_node/Cargo.toml
+++ b/beacon_node/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "beacon_node"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Paul Hauner <paul@paulhauner.com>", "Age Manning <Age@AgeManning.com"]
 edition = "2018"

--- a/beacon_node/beacon_chain/src/builder.rs
+++ b/beacon_node/beacon_chain/src/builder.rs
@@ -97,11 +97,12 @@ pub struct BeaconChainBuilder<T: BeaconChainTypes> {
    #[allow(clippy::type_complexity)]
    store: Option<Arc<HotColdDB<T::EthSpec, T::HotStore, T::ColdStore>>>,
    store_migrator: Option<T::StoreMigrator>,
-    canonical_head: Option<BeaconSnapshot<T::EthSpec>>,
-    /// The finalized checkpoint to anchor the chain. May be genesis or a higher
-    /// checkpoint.
-    pub finalized_snapshot: Option<BeaconSnapshot<T::EthSpec>>,
+    pub genesis_time: Option<u64>,
    genesis_block_root: Option<Hash256>,
+    #[allow(clippy::type_complexity)]
+    fork_choice: Option<
+        ForkChoice<BeaconForkChoiceStore<T::EthSpec, T::HotStore, T::ColdStore>, T::EthSpec>,
+    >,
    op_pool: Option<OperationPool<T::EthSpec>>,
    eth1_chain: Option<Eth1Chain<T::Eth1Chain, T::EthSpec>>,
    event_handler: Option<T::EventHandler>,
@@ -146,9 +147,9 @@ where
        Self {
            store: None,
            store_migrator: None,
-            canonical_head: None,
-            finalized_snapshot: None,
+            genesis_time: None,
            genesis_block_root: None,
+            fork_choice: None,
            op_pool: None,
            eth1_chain: None,
            event_handler: None,
@@ -278,22 +279,31 @@ where
                    .to_string()
            })?;

-        self.genesis_block_root = Some(chain.genesis_block_root);
-        self.head_tracker = Some(
-            HeadTracker::from_ssz_container(&chain.ssz_head_tracker)
-                .map_err(|e| format!("Failed to decode head tracker for database: {:?}", e))?,
-        );
+        let persisted_fork_choice = store
+            .get_item::<PersistedForkChoice>(&Hash256::from_slice(&FORK_CHOICE_DB_KEY))
+            .map_err(|e| format!("DB error when reading persisted fork choice: {:?}", e))?
+            .ok_or_else(|| "No persisted fork choice present in database.".to_string())?;

-        let head_block_root = chain.canonical_head_block_root;
-        let head_block = store
-            .get_item::<SignedBeaconBlock<TEthSpec>>(&head_block_root)
-            .map_err(|e| format!("DB error when reading head block: {:?}", e))?
-            .ok_or_else(|| "Head block not found in store".to_string())?;
-        let head_state_root = head_block.state_root();
-        let head_state = store
-            .get_state(&head_state_root, Some(head_block.slot()))
-            .map_err(|e| format!("DB error when reading head state: {:?}", e))?
-            .ok_or_else(|| "Head state not found in store".to_string())?;
+        let fc_store = BeaconForkChoiceStore::from_persisted(
+            persisted_fork_choice.fork_choice_store,
+            store.clone(),
+        )
+        .map_err(|e| format!("Unable to load ForkChoiceStore: {:?}", e))?;
+
+        let fork_choice =
+            ForkChoice::from_persisted(persisted_fork_choice.fork_choice, fc_store)
+                .map_err(|e| format!("Unable to parse persisted fork choice from disk: {:?}", e))?;
+
+        let genesis_block = store
+            .get_item::<SignedBeaconBlock<TEthSpec>>(&chain.genesis_block_root)
+            .map_err(|e| format!("DB error when reading genesis block: {:?}", e))?
+            .ok_or_else(|| "Genesis block not found in store".to_string())?;
+        let genesis_state = store
+            .get_state(&genesis_block.state_root(), Some(genesis_block.slot()))
+            .map_err(|e| format!("DB error when reading genesis state: {:?}", e))?
+            .ok_or_else(|| "Genesis block not found in store".to_string())?;
+
+        self.genesis_time = Some(genesis_state.genesis_time);

        self.op_pool = Some(
            store
@@ -303,35 +313,16 @@ where
                .unwrap_or_else(OperationPool::new),
        );

-        let finalized_block_root = head_state.finalized_checkpoint.root;
-        let finalized_block = store
-            .get_item::<SignedBeaconBlock<TEthSpec>>(&finalized_block_root)
-            .map_err(|e| format!("DB error when reading finalized block: {:?}", e))?
-            .ok_or_else(|| "Finalized block not found in store".to_string())?;
-        let finalized_state_root = finalized_block.state_root();
-        let finalized_state = store
-            .get_state(&finalized_state_root, Some(finalized_block.slot()))
-            .map_err(|e| format!("DB error when reading finalized state: {:?}", e))?
-            .ok_or_else(|| "Finalized state not found in store".to_string())?;
-
-        self.finalized_snapshot = Some(BeaconSnapshot {
-            beacon_block_root: finalized_block_root,
-            beacon_block: finalized_block,
-            beacon_state_root: finalized_state_root,
-            beacon_state: finalized_state,
-        });
-
-        self.canonical_head = Some(BeaconSnapshot {
-            beacon_block_root: head_block_root,
-            beacon_block: head_block,
-            beacon_state_root: head_state_root,
-            beacon_state: head_state,
-        });
-
        let pubkey_cache = ValidatorPubkeyCache::load_from_file(pubkey_cache_path)
            .map_err(|e| format!("Unable to open persisted pubkey cache: {:?}", e))?;

+        self.genesis_block_root = Some(chain.genesis_block_root);
+        self.head_tracker = Some(
+            HeadTracker::from_ssz_container(&chain.ssz_head_tracker)
+                .map_err(|e| format!("Failed to decode head tracker for database: {:?}", e))?,
+        );
        self.validator_pubkey_cache = Some(pubkey_cache);
+        self.fork_choice = Some(fork_choice);

        Ok(self)
    }
@@ -374,12 +365,20 @@ where
                )
            })?;

-        self.finalized_snapshot = Some(BeaconSnapshot {
+        let genesis = BeaconSnapshot {
            beacon_block_root,
            beacon_block,
            beacon_state_root,
            beacon_state,
-        });
+        };
+
+        let fc_store = BeaconForkChoiceStore::get_forkchoice_store(store, &genesis);
+
+        let fork_choice = ForkChoice::from_genesis(fc_store, &genesis.beacon_block.message)
+            .map_err(|e| format!("Unable to build initialize ForkChoice: {:?}", e))?;
+
+        self.fork_choice = Some(fork_choice);
+        self.genesis_time = Some(genesis.beacon_state.genesis_time);

        Ok(self.empty_op_pool())
    }
@@ -457,23 +456,73 @@ where
            .store
            .clone()
            .ok_or_else(|| "Cannot build without a store.".to_string())?;
+        let mut fork_choice = self
+            .fork_choice
+            .ok_or_else(|| "Cannot build without fork choice.".to_string())?;
+        let genesis_block_root = self
+            .genesis_block_root
+            .ok_or_else(|| "Cannot build without a genesis block root".to_string())?;

-        // If this beacon chain is being loaded from disk, use the stored head. Otherwise, just use
-        // the finalized checkpoint (which is probably genesis).
-        let mut canonical_head = if let Some(head) = self.canonical_head {
-            head
+        let current_slot = if slot_clock
+            .is_prior_to_genesis()
+            .ok_or_else(|| "Unable to read slot clock".to_string())?
+        {
+            self.spec.genesis_slot
        } else {
-            self.finalized_snapshot
-                .ok_or_else(|| "Cannot build without a state".to_string())?
+            slot_clock
+                .now()
+                .ok_or_else(|| "Unable to read slot".to_string())?
        };

+        let head_block_root = fork_choice
+            .get_head(current_slot)
+            .map_err(|e| format!("Unable to get fork choice head: {:?}", e))?;
+
+        let head_block = store
+            .get_item::<SignedBeaconBlock<TEthSpec>>(&head_block_root)
+            .map_err(|e| format!("DB error when reading head block: {:?}", e))?
+            .ok_or_else(|| "Head block not found in store".to_string())?;
+        let head_state_root = head_block.state_root();
+        let head_state = store
+            .get_state(&head_state_root, Some(head_block.slot()))
+            .map_err(|e| format!("DB error when reading head state: {:?}", e))?
+            .ok_or_else(|| "Head state not found in store".to_string())?;
+
+        let mut canonical_head = BeaconSnapshot {
+            beacon_block_root: head_block_root,
+            beacon_block: head_block,
+            beacon_state_root: head_state_root,
+            beacon_state: head_state,
+        };
+
+        if canonical_head.beacon_block.state_root() != canonical_head.beacon_state_root {
+            return Err("beacon_block.state_root != beacon_state".to_string());
+        }
+
        canonical_head
            .beacon_state
            .build_all_caches(&self.spec)
            .map_err(|e| format!("Failed to build state caches: {:?}", e))?;

-        if canonical_head.beacon_block.state_root() != canonical_head.beacon_state_root {
-            return Err("beacon_block.state_root != beacon_state".to_string());
+        // Perform a check to ensure that the finalization points of the head and fork choice are
+        // consistent.
+        //
+        // This is a sanity check to detect database corruption.
+        let fc_finalized = fork_choice.finalized_checkpoint();
+        let head_finalized = canonical_head.beacon_state.finalized_checkpoint;
+        if fc_finalized != head_finalized {
+            if head_finalized.root == Hash256::zero()
+                && head_finalized.epoch == fc_finalized.epoch
+                && fc_finalized.root == genesis_block_root
+            {
+                // This is a legal edge-case encountered during genesis.
+            } else {
+                return Err(format!(
+                    "Database corrupt: fork choice is finalized at {:?} whilst head is finalized at \
+                    {:?}",
+                    fc_finalized, head_finalized
+                ));
+            }
        }

        let pubkey_cache_path = self
@@ -485,26 +534,6 @@ where
                .map_err(|e| format!("Unable to init validator pubkey cache: {:?}", e))
        })?;

-        let persisted_fork_choice = store
-            .get_item::<PersistedForkChoice>(&Hash256::from_slice(&FORK_CHOICE_DB_KEY))
-            .map_err(|e| format!("DB error when reading persisted fork choice: {:?}", e))?;
-
-        let fork_choice = if let Some(persisted) = persisted_fork_choice {
-            let fc_store =
-                BeaconForkChoiceStore::from_persisted(persisted.fork_choice_store, store.clone())
-                    .map_err(|e| format!("Unable to load ForkChoiceStore: {:?}", e))?;
-
-            ForkChoice::from_persisted(persisted.fork_choice, fc_store)
-                .map_err(|e| format!("Unable to parse persisted fork choice from disk: {:?}", e))?
-        } else {
-            let genesis = &canonical_head;
-
-            let fc_store = BeaconForkChoiceStore::get_forkchoice_store(store.clone(), genesis);
-
-            ForkChoice::from_genesis(fc_store, &genesis.beacon_block.message)
-                .map_err(|e| format!("Unable to build initialize ForkChoice: {:?}", e))?
-        };
-
        let beacon_chain = BeaconChain {
            spec: self.spec,
            config: self.chain_config,
@@ -533,9 +562,7 @@ where
            eth1_chain: self.eth1_chain,
            genesis_validators_root: canonical_head.beacon_state.genesis_validators_root,
            canonical_head: TimeoutRwLock::new(canonical_head.clone()),
-            genesis_block_root: self
-                .genesis_block_root
-                .ok_or_else(|| "Cannot build without a genesis block root".to_string())?,
+            genesis_block_root,
            fork_choice: RwLock::new(fork_choice),
            event_handler: self
                .event_handler
@@ -634,11 +661,8 @@ where
    /// Requires the state to be initialized.
    pub fn testing_slot_clock(self, slot_duration: Duration) -> Result<Self, String> {
        let genesis_time = self
-            .finalized_snapshot
-            .as_ref()
-            .ok_or_else(|| "testing_slot_clock requires an initialized state")?
-            .beacon_state
-            .genesis_time;
+            .genesis_time
+            .ok_or_else(|| "testing_slot_clock requires an initialized state")?;

        let slot_clock = TestingSlotClock::new(
            Slot::new(0),
--- a/beacon_node/beacon_chain/src/persisted_beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/persisted_beacon_chain.rs
@@ -6,6 +6,13 @@ use types::Hash256;

 #[derive(Clone, Encode, Decode)]
 pub struct PersistedBeaconChain {
+    /// This value is ignored to resolve the issue described here:
+    ///
+    /// https://github.com/sigp/lighthouse/pull/1639
+    ///
+    /// The following PR will clean-up and remove this field:
+    ///
+    /// https://github.com/sigp/lighthouse/pull/1638
    pub canonical_head_block_root: Hash256,
    pub genesis_block_root: Hash256,
    pub ssz_head_tracker: SszHeadTracker,
--- a/beacon_node/beacon_chain/tests/persistence_tests.rs
+++ b/beacon_node/beacon_chain/tests/persistence_tests.rs
@@ -153,8 +153,11 @@ fn assert_chains_pretty_much_the_same<T: BeaconChainTypes>(a: &BeaconChain<T>, b
        a.genesis_block_root, b.genesis_block_root,
        "genesis_block_root should be equal"
    );
+
+    let slot = a.slot().unwrap();
    assert!(
-        *a.fork_choice.read() == *b.fork_choice.read(),
-        "fork_choice should be equal"
+        a.fork_choice.write().get_head(slot).unwrap()
+            == b.fork_choice.write().get_head(slot).unwrap(),
+        "fork_choice heads should be equal"
    );
 }
--- a/beacon_node/client/src/builder.rs
+++ b/beacon_node/client/src/builder.rs
@@ -713,11 +713,8 @@ where
            .ok_or_else(|| "system_time_slot_clock requires a beacon_chain_builder")?;

        let genesis_time = beacon_chain_builder
-            .finalized_snapshot
-            .as_ref()
-            .ok_or_else(|| "system_time_slot_clock requires an initialized beacon state")?
-            .beacon_state
-            .genesis_time;
+            .genesis_time
+            .ok_or_else(|| "system_time_slot_clock requires an initialized beacon state")?;

        let spec = self
            .chain_spec
--- a/beacon_node/eth2_libp2p/src/behaviour/mod.rs
+++ b/beacon_node/eth2_libp2p/src/behaviour/mod.rs
@@ -1,6 +1,7 @@
 use crate::peer_manager::{score::PeerAction, PeerManager, PeerManagerEvent};
 use crate::rpc::*;
-use crate::types::{EnrBitfield, GossipEncoding, GossipKind, GossipTopic, SubnetDiscovery};
+use crate::service::METADATA_FILENAME;
+use crate::types::{GossipEncoding, GossipKind, GossipTopic, SubnetDiscovery};
 use crate::Eth2Enr;
 use crate::{error, metrics, Enr, NetworkConfig, NetworkGlobals, PubsubMessage, TopicHash};
 use futures::prelude::*;
@@ -23,9 +24,9 @@ use libp2p::{
    PeerId,
 };
 use slog::{crit, debug, o, trace, warn};
-use ssz::{Decode, Encode};
+use ssz::Encode;
 use std::fs::File;
-use std::io::{Read, Write};
+use std::io::Write;
 use std::path::PathBuf;
 use std::{
    collections::VecDeque,
@@ -38,7 +39,6 @@ use types::{EnrForkId, EthSpec, SignedBeaconBlock, SubnetId};
 mod handler;

 const MAX_IDENTIFY_ADDRESSES: usize = 10;
-const METADATA_FILENAME: &str = "metadata";

 /// Builds the network behaviour that manages the core protocols of eth2.
 /// This core behaviour is managed by `Behaviour` which adds peer management to all core
@@ -58,8 +58,6 @@ pub struct Behaviour<TSpec: EthSpec> {
    events: VecDeque<BehaviourEvent<TSpec>>,
    /// Queue of peers to disconnect and an optional reason for the disconnection.
    peers_to_dc: VecDeque<(PeerId, Option<GoodbyeReason>)>,
-    /// The current meta data of the node, so respond to pings and get metadata
-    meta_data: MetaData<TSpec>,
    /// A collections of variables accessible outside the network service.
    network_globals: Arc<NetworkGlobals<TSpec>>,
    /// Keeps track of the current EnrForkId for upgrading gossipsub topics.
@@ -95,8 +93,6 @@ impl<TSpec: EthSpec> Behaviour<TSpec> {
            .eth2()
            .expect("Local ENR must have a fork id");

-        let meta_data = load_or_build_metadata(&net_conf.network_dir, &log);
-
        let gossipsub = Gossipsub::new(MessageAuthenticity::Anonymous, net_conf.gs_config.clone())
            .map_err(|e| format!("Could not construct gossipsub: {:?}", e))?;

@@ -115,7 +111,6 @@ impl<TSpec: EthSpec> Behaviour<TSpec> {
                .await?,
            events: VecDeque::new(),
            peers_to_dc: VecDeque::new(),
-            meta_data,
            network_globals,
            enr_fork_id,
            waker: None,
@@ -407,21 +402,31 @@ impl<TSpec: EthSpec> Behaviour<TSpec> {

    /// Updates the current meta data of the node to match the local ENR.
    fn update_metadata(&mut self) {
-        self.meta_data.seq_number += 1;
-        self.meta_data.attnets = self
+        let local_attnets = self
            .peer_manager
            .discovery()
            .local_enr()
            .bitfield::<TSpec>()
            .expect("Local discovery must have bitfield");
+
+        {
+            // write lock scope
+            let mut meta_data = self.network_globals.local_metadata.write();
+            meta_data.seq_number += 1;
+            meta_data.attnets = local_attnets;
+        }
        // Save the updated metadata to disk
-        save_metadata_to_disk(&self.network_dir, self.meta_data.clone(), &self.log);
+        save_metadata_to_disk(
+            &self.network_dir,
+            self.network_globals.local_metadata.read().clone(),
+            &self.log,
+        );
    }

    /// Sends a Ping request to the peer.
    fn ping(&mut self, id: RequestId, peer_id: PeerId) {
        let ping = crate::rpc::Ping {
-            data: self.meta_data.seq_number,
+            data: self.network_globals.local_metadata.read().seq_number,
        };
        trace!(self.log, "Sending Ping"; "request_id" => id, "peer_id" => peer_id.to_string());

@@ -432,7 +437,7 @@ impl<TSpec: EthSpec> Behaviour<TSpec> {
    /// Sends a Pong response to the peer.
    fn pong(&mut self, id: PeerRequestId, peer_id: PeerId) {
        let ping = crate::rpc::Ping {
-            data: self.meta_data.seq_number,
+            data: self.network_globals.local_metadata.read().seq_number,
        };
        trace!(self.log, "Sending Pong"; "request_id" => id.1, "peer_id" => peer_id.to_string());
        let event = RPCCodedResponse::Success(RPCResponse::Pong(ping));
@@ -448,7 +453,9 @@ impl<TSpec: EthSpec> Behaviour<TSpec> {

    /// Sends a METADATA response to a peer.
    fn send_meta_data_response(&mut self, id: PeerRequestId, peer_id: PeerId) {
-        let event = RPCCodedResponse::Success(RPCResponse::MetaData(self.meta_data.clone()));
+        let event = RPCCodedResponse::Success(RPCResponse::MetaData(
+            self.network_globals.local_metadata.read().clone(),
+        ));
        self.eth2_rpc.send_response(peer_id, id, event);
    }

@@ -1107,45 +1114,8 @@ pub enum BehaviourEvent<TSpec: EthSpec> {
    StatusPeer(PeerId),
 }

-/// Load metadata from persisted file. Return default metadata if loading fails.
-fn load_or_build_metadata<E: EthSpec>(network_dir: &PathBuf, log: &slog::Logger) -> MetaData<E> {
-    // Default metadata
-    let mut meta_data = MetaData {
-        seq_number: 0,
-        attnets: EnrBitfield::<E>::default(),
-    };
-    // Read metadata from persisted file if available
-    let metadata_path = network_dir.join(METADATA_FILENAME);
-    if let Ok(mut metadata_file) = File::open(metadata_path) {
-        let mut metadata_ssz = Vec::new();
-        if metadata_file.read_to_end(&mut metadata_ssz).is_ok() {
-            match MetaData::<E>::from_ssz_bytes(&metadata_ssz) {
-                Ok(persisted_metadata) => {
-                    meta_data.seq_number = persisted_metadata.seq_number;
-                    // Increment seq number if persisted attnet is not default
-                    if persisted_metadata.attnets != meta_data.attnets {
-                        meta_data.seq_number += 1;
-                    }
-                    debug!(log, "Loaded metadata from disk");
-                }
-                Err(e) => {
-                    debug!(
-                        log,
-                        "Metadata from file could not be decoded";
-                        "error" => format!("{:?}", e),
-                    );
-                }
-            }
-        }
-    };
-
-    debug!(log, "Metadata sequence number"; "seq_num" => meta_data.seq_number);
-    save_metadata_to_disk(network_dir, meta_data.clone(), &log);
-    meta_data
-}
-
 /// Persist metadata to disk
-fn save_metadata_to_disk<E: EthSpec>(dir: &PathBuf, metadata: MetaData<E>, log: &slog::Logger) {
+pub fn save_metadata_to_disk<E: EthSpec>(dir: &PathBuf, metadata: MetaData<E>, log: &slog::Logger) {
    let _ = std::fs::create_dir_all(&dir);
    match File::create(dir.join(METADATA_FILENAME))
        .and_then(|mut f| f.write_all(&metadata.as_ssz_bytes()))
--- a/beacon_node/eth2_libp2p/src/config.rs
+++ b/beacon_node/eth2_libp2p/src/config.rs
@@ -1,5 +1,5 @@
 use crate::types::GossipKind;
-use crate::Enr;
+use crate::{Enr, PeerIdSerialized};
 use discv5::{Discv5Config, Discv5ConfigBuilder};
 use libp2p::gossipsub::{
    GossipsubConfig, GossipsubConfigBuilder, GossipsubMessage, MessageId, ValidationMode,
@@ -58,6 +58,9 @@ pub struct Config {
    /// List of libp2p nodes to initially connect to.
    pub libp2p_nodes: Vec<Multiaddr>,

+    /// List of trusted libp2p nodes which are not scored.
+    pub trusted_peers: Vec<PeerIdSerialized>,
+
    /// Client version
    pub client_version: String,

@@ -139,6 +142,7 @@ impl Default for Config {
            boot_nodes_enr: vec![],
            boot_nodes_multiaddr: vec![],
            libp2p_nodes: vec![],
+            trusted_peers: vec![],
            client_version: lighthouse_version::version_with_platform(),
            disable_discovery: false,
            topics,
--- a/beacon_node/eth2_libp2p/src/lib.rs
+++ b/beacon_node/eth2_libp2p/src/lib.rs
@@ -14,6 +14,50 @@ pub mod rpc;
 mod service;
 pub mod types;

+use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
+use std::str::FromStr;
+
+/// Wrapper over a libp2p `PeerId` which implements `Serialize` and `Deserialize`
+#[derive(Clone, Debug)]
+pub struct PeerIdSerialized(libp2p::PeerId);
+
+impl From<PeerIdSerialized> for PeerId {
+    fn from(peer_id: PeerIdSerialized) -> Self {
+        peer_id.0
+    }
+}
+
+impl FromStr for PeerIdSerialized {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(
+            PeerId::from_str(s).map_err(|e| format!("Invalid peer id: {}", e))?,
+        ))
+    }
+}
+
+impl Serialize for PeerIdSerialized {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.0.to_string())
+    }
+}
+
+impl<'de> Deserialize<'de> for PeerIdSerialized {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let s: String = Deserialize::deserialize(deserializer)?;
+        Ok(Self(PeerId::from_str(&s).map_err(|e| {
+            de::Error::custom(format!("Failed to deserialise peer id: {:?}", e))
+        })?))
+    }
+}
+
 pub use crate::types::{error, Enr, GossipTopic, NetworkGlobals, PubsubMessage, SubnetDiscovery};
 pub use behaviour::{BehaviourEvent, PeerRequestId, Request, Response};
 pub use config::Config as NetworkConfig;
--- a/beacon_node/eth2_libp2p/src/peer_manager/mod.rs
+++ b/beacon_node/eth2_libp2p/src/peer_manager/mod.rs
@@ -133,9 +133,9 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
    pub fn goodbye_peer(&mut self, peer_id: &PeerId, reason: GoodbyeReason) {
        // get the peer info
        if let Some(info) = self.network_globals.peers.write().peer_info_mut(peer_id) {
-            debug!(self.log, "Sending goodbye to peer"; "peer_id" => peer_id.to_string(), "reason" => reason.to_string(), "score" => info.score.to_string());
+            debug!(self.log, "Sending goodbye to peer"; "peer_id" => peer_id.to_string(), "reason" => reason.to_string(), "score" => info.score().to_string());
            // Goodbye's are fatal
-            info.score.apply_peer_action(PeerAction::Fatal);
+            info.apply_peer_action_to_score(PeerAction::Fatal);
            if info.connection_status.is_connected_or_dialing() {
                self.events
                    .push(PeerManagerEvent::DisconnectPeer(peer_id.clone(), reason));
@@ -155,12 +155,12 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
        let mut unban_peer = None;

        if let Some(info) = self.network_globals.peers.write().peer_info_mut(peer_id) {
-            let previous_state = info.score.state();
-            info.score.apply_peer_action(action);
-            if previous_state != info.score.state() {
-                match info.score.state() {
+            let previous_state = info.score_state();
+            info.apply_peer_action_to_score(action);
+            if previous_state != info.score_state() {
+                match info.score_state() {
                    ScoreState::Banned => {
-                        debug!(self.log, "Peer has been banned"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string());
+                        debug!(self.log, "Peer has been banned"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string());
                        ban_peer = Some(peer_id.clone());
                        if info.connection_status.is_connected_or_dialing() {
                            self.events.push(PeerManagerEvent::DisconnectPeer(
@@ -170,7 +170,7 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
                        }
                    }
                    ScoreState::Disconnected => {
-                        debug!(self.log, "Peer transitioned to disconnect state"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string(), "past_state" => previous_state.to_string());
+                        debug!(self.log, "Peer transitioned to disconnect state"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string(), "past_state" => previous_state.to_string());
                        // disconnect the peer if it's currently connected or dialing
                        unban_peer = Some(peer_id.clone());
                        if info.connection_status.is_connected_or_dialing() {
@@ -182,13 +182,13 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
                        // TODO: Update the peer manager to inform that the peer is disconnecting.
                    }
                    ScoreState::Healthy => {
-                        debug!(self.log, "Peer transitioned to healthy state"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string(), "past_state" => previous_state.to_string());
+                        debug!(self.log, "Peer transitioned to healthy state"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string(), "past_state" => previous_state.to_string());
                        // unban the peer if it was previously banned.
                        unban_peer = Some(peer_id.clone());
                    }
                }
            } else {
-                debug!(self.log, "Peer score adjusted"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string());
+                debug!(self.log, "Peer score adjusted"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string());
            }
        }

@@ -689,9 +689,9 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
        let mut to_unban_peers = Vec::new();

        for (peer_id, info) in pdb.peers_mut() {
-            let previous_state = info.score.state();
+            let previous_state = info.score_state();
            // Update scores
-            info.score.update();
+            info.score_update();

            /* TODO: Implement logic about connection lifetimes
            match info.connection_status {
@@ -746,10 +746,10 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
            */

            // handle score transitions
-            if previous_state != info.score.state() {
-                match info.score.state() {
+            if previous_state != info.score_state() {
+                match info.score_state() {
                    ScoreState::Banned => {
-                        debug!(self.log, "Peer has been banned"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string());
+                        debug!(self.log, "Peer has been banned"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string());
                        to_ban_peers.push(peer_id.clone());
                        if info.connection_status.is_connected_or_dialing() {
                            self.events.push(PeerManagerEvent::DisconnectPeer(
@@ -759,7 +759,7 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
                        }
                    }
                    ScoreState::Disconnected => {
-                        debug!(self.log, "Peer transitioned to disconnect state"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string(), "past_state" => previous_state.to_string());
+                        debug!(self.log, "Peer transitioned to disconnect state"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string(), "past_state" => previous_state.to_string());
                        // disconnect the peer if it's currently connected or dialing
                        to_unban_peers.push(peer_id.clone());
                        if info.connection_status.is_connected_or_dialing() {
@@ -771,7 +771,7 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
                        // TODO: Update peer manager to report that it's disconnecting.
                    }
                    ScoreState::Healthy => {
-                        debug!(self.log, "Peer transitioned to healthy state"; "peer_id" => peer_id.to_string(), "score" => info.score.to_string(), "past_state" => previous_state.to_string());
+                        debug!(self.log, "Peer transitioned to healthy state"; "peer_id" => peer_id.to_string(), "score" => info.score().to_string(), "past_state" => previous_state.to_string());
                        // unban the peer if it was previously banned.
                        to_unban_peers.push(peer_id.clone());
                    }
@@ -821,7 +821,7 @@ impl<TSpec: EthSpec> PeerManager<TSpec> {
                .take(connected_peer_count - self.target_peers)
                //we only need to disconnect peers with healthy scores, since the others got already
                //disconnected in update_peer_scores
-                .filter(|(_, info)| info.score.state() == ScoreState::Healthy)
+                .filter(|(_, info)| info.score_state() == ScoreState::Healthy)
            {
                self.events.push(PeerManagerEvent::DisconnectPeer(
                    (*peer_id).clone(),
--- a/beacon_node/eth2_libp2p/src/peer_manager/peer_info.rs
+++ b/beacon_node/eth2_libp2p/src/peer_manager/peer_info.rs
@@ -1,5 +1,5 @@
 use super::client::Client;
-use super::score::Score;
+use super::score::{PeerAction, Score, ScoreState};
 use super::PeerSyncStatus;
 use crate::rpc::MetaData;
 use crate::Multiaddr;
@@ -19,7 +19,7 @@ pub struct PeerInfo<T: EthSpec> {
    /// The connection status of the peer
    _status: PeerStatus,
    /// The peers reputation
-    pub score: Score,
+    score: Score,
    /// Client managing this peer
    pub client: Client,
    /// Connection status of this peer
@@ -36,6 +36,8 @@ pub struct PeerInfo<T: EthSpec> {
    /// necessary.
    #[serde(skip)]
    pub min_ttl: Option<Instant>,
+    /// Is the peer a trusted peer.
+    pub is_trusted: bool,
 }

 impl<TSpec: EthSpec> Default for PeerInfo<TSpec> {
@@ -49,11 +51,21 @@ impl<TSpec: EthSpec> Default for PeerInfo<TSpec> {
            sync_status: PeerSyncStatus::Unknown,
            meta_data: None,
            min_ttl: None,
+            is_trusted: false,
        }
    }
 }

 impl<T: EthSpec> PeerInfo<T> {
+    /// Return a PeerInfo struct for a trusted peer.
+    pub fn trusted_peer_info() -> Self {
+        PeerInfo {
+            score: Score::max_score(),
+            is_trusted: true,
+            ..Default::default()
+        }
+    }
+
    /// Returns if the peer is subscribed to a given `SubnetId`
    pub fn on_subnet(&self, subnet_id: SubnetId) -> bool {
        if let Some(meta_data) = &self.meta_data {
@@ -69,6 +81,38 @@ impl<T: EthSpec> PeerInfo<T> {
    pub fn has_future_duty(&self) -> bool {
        self.min_ttl.map_or(false, |i| i >= Instant::now())
    }
+
+    /// Returns score of the peer.
+    pub fn score(&self) -> Score {
+        self.score
+    }
+
+    /// Returns the state of the peer based on the score.
+    pub(crate) fn score_state(&self) -> ScoreState {
+        self.score.state()
+    }
+
+    /// Applies decay rates to a non-trusted peer's score.
+    pub fn score_update(&mut self) {
+        if !self.is_trusted {
+            self.score.update()
+        }
+    }
+
+    /// Apply peer action to a non-trusted peer's score.
+    pub fn apply_peer_action_to_score(&mut self, peer_action: PeerAction) {
+        if !self.is_trusted {
+            self.score.apply_peer_action(peer_action)
+        }
+    }
+
+    #[cfg(test)]
+    /// Add an f64 to a non-trusted peer's score abiding by the limits.
+    pub fn add_to_score(&mut self, score: f64) {
+        if !self.is_trusted {
+            self.score.add(score)
+        }
+    }
 }

 #[derive(Clone, Debug, Serialize)]
--- a/beacon_node/eth2_libp2p/src/peer_manager/peerdb.rs
+++ b/beacon_node/eth2_libp2p/src/peer_manager/peerdb.rs
@@ -86,12 +86,17 @@ impl BannedPeersCount {
 }

 impl<TSpec: EthSpec> PeerDB<TSpec> {
-    pub fn new(log: &slog::Logger) -> Self {
+    pub fn new(trusted_peers: Vec<PeerId>, log: &slog::Logger) -> Self {
+        // Initialize the peers hashmap with trusted peers
+        let peers = trusted_peers
+            .into_iter()
+            .map(|peer_id| (peer_id, PeerInfo::trusted_peer_info()))
+            .collect();
        Self {
            log: log.clone(),
            disconnected_peers: 0,
            banned_peers_count: BannedPeersCount::new(),
-            peers: HashMap::new(),
+            peers,
        }
    }

@@ -101,7 +106,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
    pub fn score(&self, peer_id: &PeerId) -> Score {
        self.peers
            .get(peer_id)
-            .map_or(Score::default(), |info| info.score)
+            .map_or(Score::default(), |info| info.score())
    }

    /// Returns an iterator over all peers in the db.
@@ -159,7 +164,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
    /// Returns true if the Peer is banned.
    pub fn is_banned(&self, peer_id: &PeerId) -> bool {
        if let Some(peer) = self.peers.get(peer_id) {
-            match peer.score.state() {
+            match peer.score().state() {
                ScoreState::Banned => true,
                _ => self.ip_is_banned(peer),
            }
@@ -181,7 +186,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
    /// Returns true if the Peer is either banned or in the disconnected state.
    pub fn is_banned_or_disconnected(&self, peer_id: &PeerId) -> bool {
        if let Some(peer) = self.peers.get(peer_id) {
-            match peer.score.state() {
+            match peer.score().state() {
                ScoreState::Banned | ScoreState::Disconnected => true,
                _ => self.ip_is_banned(peer),
            }
@@ -264,7 +269,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
            .collect::<Vec<_>>();

        connected.shuffle(&mut rand::thread_rng());
-        connected.sort_by_key(|(_, info)| info.score);
+        connected.sort_by_key(|(_, info)| info.score());
        connected
    }

@@ -279,7 +284,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
            .iter()
            .filter(|(_, info)| is_status(&info.connection_status))
            .collect::<Vec<_>>();
-        by_status.sort_by_key(|(_, info)| info.score);
+        by_status.sort_by_key(|(_, info)| info.score());
        by_status.into_iter().rev().collect()
    }

@@ -291,7 +296,7 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
        self.peers
            .iter()
            .filter(|(_, info)| is_status(&info.connection_status))
-            .max_by_key(|(_, info)| info.score)
+            .max_by_key(|(_, info)| info.score())
            .map(|(id, _)| id)
    }

@@ -455,8 +460,8 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
                .filter(|(_, info)| info.connection_status.is_banned())
                .min_by(|(_, info_a), (_, info_b)| {
                    info_a
-                        .score
-                        .partial_cmp(&info_b.score)
+                        .score()
+                        .partial_cmp(&info_b.score())
                        .unwrap_or(std::cmp::Ordering::Equal)
                }) {
                self.banned_peers_count
@@ -485,8 +490,8 @@ impl<TSpec: EthSpec> PeerDB<TSpec> {
                .filter(|(_, info)| info.connection_status.is_disconnected())
                .min_by(|(_, info_a), (_, info_b)| {
                    info_a
-                        .score
-                        .partial_cmp(&info_b.score)
+                        .score()
+                        .partial_cmp(&info_b.score())
                        .unwrap_or(std::cmp::Ordering::Equal)
                })
                .map(|(id, _)| id.clone())
@@ -543,13 +548,13 @@ mod tests {

    fn add_score<TSpec: EthSpec>(db: &mut PeerDB<TSpec>, peer_id: &PeerId, score: f64) {
        if let Some(info) = db.peer_info_mut(peer_id) {
-            info.score.add(score);
+            info.add_to_score(score);
        }
    }

    fn get_db() -> PeerDB<M> {
        let log = build_log(slog::Level::Debug, false);
-        PeerDB::new(&log)
+        PeerDB::new(vec![], &log)
    }

    #[test]
@@ -938,4 +943,28 @@ mod tests {
        assert!(pdb.is_banned(&p1));
        assert!(!pdb.is_banned(&p2));
    }
+
+    #[test]
+    fn test_trusted_peers_score() {
+        let trusted_peer = PeerId::random();
+        let log = build_log(slog::Level::Debug, false);
+        let mut pdb: PeerDB<M> = PeerDB::new(vec![trusted_peer.clone()], &log);
+
+        pdb.connect_ingoing(&trusted_peer);
+
+        // Check trusted status and score
+        assert!(pdb.peer_info(&trusted_peer).unwrap().is_trusted);
+        assert_eq!(
+            pdb.peer_info(&trusted_peer).unwrap().score().score(),
+            Score::max_score().score()
+        );
+
+        // Adding/Subtracting score should have no effect on a trusted peer
+        add_score(&mut pdb, &trusted_peer, -50.0);
+
+        assert_eq!(
+            pdb.peer_info(&trusted_peer).unwrap().score().score(),
+            Score::max_score().score()
+        );
+    }
 }
--- a/beacon_node/eth2_libp2p/src/peer_manager/score.rs
+++ b/beacon_node/eth2_libp2p/src/peer_manager/score.rs
@@ -145,6 +145,13 @@ impl std::fmt::Display for ScoreState {
 }

 impl Score {
+    /// Return max possible score.
+    pub fn max_score() -> Self {
+        Score {
+            score: MAX_SCORE,
+            last_updated: Instant::now(),
+        }
+    }
    /// Access to the underlying score.
    pub fn score(&self) -> f64 {
        self.score
--- a/beacon_node/eth2_libp2p/src/rpc/codec/ssz_snappy.rs
+++ b/beacon_node/eth2_libp2p/src/rpc/codec/ssz_snappy.rs
@@ -99,6 +99,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyInboundCodec<TSpec> {
    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
        if self.len.is_none() {
            // Decode the length of the uncompressed bytes from an unsigned varint
+            // Note: length-prefix of > 10 bytes(uint64) would be a decoding error
            match self.inner.decode(src).map_err(RPCError::from)? {
                Some(length) => {
                    self.len = Some(length);
@@ -116,7 +117,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyInboundCodec<TSpec> {
        let mut reader = FrameDecoder::new(Cursor::new(&src));
        let mut decoded_buffer = vec![0; length];

-        match reader.read_exact(&mut decoded_buffer) {
+        match read_exact(&mut reader, &mut decoded_buffer, length) {
            Ok(()) => {
                // `n` is how many bytes the reader read in the compressed stream
                let n = reader.get_ref().position();
@@ -194,8 +195,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyInboundCodec<TSpec> {
                }
            }
            Err(e) => match e.kind() {
-                // Haven't received enough bytes to decode yet
-                // TODO: check if this is the only Error variant where we return `Ok(None)`
+                // Haven't received enough bytes to decode yet, wait for more
                ErrorKind::UnexpectedEof => Ok(None),
                _ => Err(e).map_err(RPCError::from),
            },
@@ -277,6 +277,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyOutboundCodec<TSpec> {
    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
        if self.len.is_none() {
            // Decode the length of the uncompressed bytes from an unsigned varint
+            // Note: length-prefix of > 10 bytes(uint64) would be a decoding error
            match self.inner.decode(src).map_err(RPCError::from)? {
                Some(length) => {
                    self.len = Some(length as usize);
@@ -293,7 +294,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyOutboundCodec<TSpec> {
        }
        let mut reader = FrameDecoder::new(Cursor::new(&src));
        let mut decoded_buffer = vec![0; length];
-        match reader.read_exact(&mut decoded_buffer) {
+        match read_exact(&mut reader, &mut decoded_buffer, length) {
            Ok(()) => {
                // `n` is how many bytes the reader read in the compressed stream
                let n = reader.get_ref().position();
@@ -364,8 +365,7 @@ impl<TSpec: EthSpec> Decoder for SSZSnappyOutboundCodec<TSpec> {
                }
            }
            Err(e) => match e.kind() {
-                // Haven't received enough bytes to decode yet
-                // TODO: check if this is the only Error variant where we return `Ok(None)`
+                // Haven't received enough bytes to decode yet, wait for more
                ErrorKind::UnexpectedEof => Ok(None),
                _ => Err(e).map_err(RPCError::from),
            },
@@ -398,7 +398,7 @@ impl<TSpec: EthSpec> OutboundCodec<RPCRequest<TSpec>> for SSZSnappyOutboundCodec
        }
        let mut reader = FrameDecoder::new(Cursor::new(&src));
        let mut decoded_buffer = vec![0; length];
-        match reader.read_exact(&mut decoded_buffer) {
+        match read_exact(&mut reader, &mut decoded_buffer, length) {
            Ok(()) => {
                // `n` is how many bytes the reader read in the compressed stream
                let n = reader.get_ref().position();
@@ -409,11 +409,67 @@ impl<TSpec: EthSpec> OutboundCodec<RPCRequest<TSpec>> for SSZSnappyOutboundCodec
                )?)))
            }
            Err(e) => match e.kind() {
-                // Haven't received enough bytes to decode yet
-                // TODO: check if this is the only Error variant where we return `Ok(None)`
+                // Haven't received enough bytes to decode yet, wait for more
                ErrorKind::UnexpectedEof => Ok(None),
                _ => Err(e).map_err(RPCError::from),
            },
        }
    }
 }
+
+/// Wrapper over `read` implementation of `FrameDecoder`.
+///
+/// Works like the standard `read_exact` implementation, except that it returns an error if length of
+// compressed bytes read from the underlying reader is greater than worst case compression length for snappy.
+fn read_exact<T: std::convert::AsRef<[u8]>>(
+    reader: &mut FrameDecoder<Cursor<T>>,
+    mut buf: &mut [u8],
+    uncompressed_length: usize,
+) -> Result<(), std::io::Error> {
+    // Calculate worst case compression length for given uncompressed length
+    let max_compressed_len = snap::raw::max_compress_len(uncompressed_length) as u64;
+
+    // Initialize the position of the reader
+    let mut pos = reader.get_ref().position();
+    let mut count = 0;
+    while !buf.is_empty() {
+        match reader.read(buf) {
+            Ok(0) => break,
+            Ok(n) => {
+                let tmp = buf;
+                buf = &mut tmp[n..];
+            }
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            Err(e) => return Err(e),
+        }
+        // Get current position of reader
+        let curr_pos = reader.get_ref().position();
+        // Note: reader should always advance forward. However, this behaviour
+        // depends on the implementation of `snap::FrameDecoder`, so it is better
+        // to check to avoid underflow panic.
+        if curr_pos > pos {
+            count += reader.get_ref().position() - pos;
+            pos = curr_pos;
+        } else {
+            return Err(std::io::Error::new(
+                ErrorKind::InvalidData,
+                "snappy: reader is not advanced forward while reading",
+            ));
+        }
+
+        if count > max_compressed_len {
+            return Err(std::io::Error::new(
+                ErrorKind::InvalidData,
+                "snappy: compressed data is > max_compressed_len",
+            ));
+        }
+    }
+    if !buf.is_empty() {
+        Err(std::io::Error::new(
+            ErrorKind::UnexpectedEof,
+            "failed to fill whole buffer",
+        ))
+    } else {
+        Ok(())
+    }
+}
--- a/beacon_node/eth2_libp2p/src/service.rs
+++ b/beacon_node/eth2_libp2p/src/service.rs
@@ -1,8 +1,10 @@
-use crate::behaviour::{Behaviour, BehaviourEvent, PeerRequestId, Request, Response};
+use crate::behaviour::{
+    save_metadata_to_disk, Behaviour, BehaviourEvent, PeerRequestId, Request, Response,
+};
 use crate::discovery::enr;
 use crate::multiaddr::Protocol;
-use crate::rpc::{GoodbyeReason, RPCResponseErrorCode, RequestId};
-use crate::types::{error, GossipKind};
+use crate::rpc::{GoodbyeReason, MetaData, RPCResponseErrorCode, RequestId};
+use crate::types::{error, EnrBitfield, GossipKind};
 use crate::EnrExt;
 use crate::{NetworkConfig, NetworkGlobals, PeerAction};
 use futures::prelude::*;
@@ -15,6 +17,7 @@ use libp2p::{
    PeerId, Swarm, Transport,
 };
 use slog::{crit, debug, info, o, trace, warn};
+use ssz::Decode;
 use std::fs::File;
 use std::io::prelude::*;
 use std::io::{Error, ErrorKind};
@@ -26,6 +29,8 @@ use types::{EnrForkId, EthSpec};
 pub const NETWORK_KEY_FILENAME: &str = "key";
 /// The maximum simultaneous libp2p connections per peer.
 const MAX_CONNECTIONS_PER_PEER: usize = 1;
+/// The filename to store our local metadata.
+pub const METADATA_FILENAME: &str = "metadata";

 /// The types of events than can be obtained from polling the libp2p service.
 ///
@@ -70,11 +75,20 @@ impl<TSpec: EthSpec> Service<TSpec> {
            enr::build_or_load_enr::<TSpec>(local_keypair.clone(), config, enr_fork_id, &log)?;

        let local_peer_id = enr.peer_id();
+
+        let meta_data = load_or_build_metadata(&config.network_dir, &log);
+
        // set up a collection of variables accessible outside of the network crate
        let network_globals = Arc::new(NetworkGlobals::new(
            enr.clone(),
            config.libp2p_port,
            config.discovery_port,
+            meta_data,
+            config
+                .trusted_peers
+                .iter()
+                .map(|x| PeerId::from(x.clone()))
+                .collect(),
            &log,
        ));

@@ -420,3 +434,43 @@ fn strip_peer_id(addr: &mut Multiaddr) {
        _ => {}
    }
 }
+
+/// Load metadata from persisted file. Return default metadata if loading fails.
+fn load_or_build_metadata<E: EthSpec>(
+    network_dir: &std::path::PathBuf,
+    log: &slog::Logger,
+) -> MetaData<E> {
+    // Default metadata
+    let mut meta_data = MetaData {
+        seq_number: 0,
+        attnets: EnrBitfield::<E>::default(),
+    };
+    // Read metadata from persisted file if available
+    let metadata_path = network_dir.join(METADATA_FILENAME);
+    if let Ok(mut metadata_file) = File::open(metadata_path) {
+        let mut metadata_ssz = Vec::new();
+        if metadata_file.read_to_end(&mut metadata_ssz).is_ok() {
+            match MetaData::<E>::from_ssz_bytes(&metadata_ssz) {
+                Ok(persisted_metadata) => {
+                    meta_data.seq_number = persisted_metadata.seq_number;
+                    // Increment seq number if persisted attnet is not default
+                    if persisted_metadata.attnets != meta_data.attnets {
+                        meta_data.seq_number += 1;
+                    }
+                    debug!(log, "Loaded metadata from disk");
+                }
+                Err(e) => {
+                    debug!(
+                        log,
+                        "Metadata from file could not be decoded";
+                        "error" => format!("{:?}", e),
+                    );
+                }
+            }
+        }
+    };
+
+    debug!(log, "Metadata sequence number"; "seq_num" => meta_data.seq_number);
+    save_metadata_to_disk(network_dir, meta_data.clone(), &log);
+    meta_data
+}
--- a/beacon_node/eth2_libp2p/src/types/globals.rs
+++ b/beacon_node/eth2_libp2p/src/types/globals.rs
@@ -1,5 +1,6 @@
 //! A collection of variables that are accessible outside of the network thread itself.
 use crate::peer_manager::PeerDB;
+use crate::rpc::MetaData;
 use crate::types::SyncState;
 use crate::Client;
 use crate::EnrExt;
@@ -22,6 +23,8 @@ pub struct NetworkGlobals<TSpec: EthSpec> {
    pub listen_port_udp: AtomicU16,
    /// The collection of known peers.
    pub peers: RwLock<PeerDB<TSpec>>,
+    // The local meta data of our node.
+    pub local_metadata: RwLock<MetaData<TSpec>>,
    /// The current gossipsub topic subscriptions.
    pub gossipsub_subscriptions: RwLock<HashSet<GossipTopic>>,
    /// The current sync status of the node.
@@ -29,14 +32,22 @@ pub struct NetworkGlobals<TSpec: EthSpec> {
 }

 impl<TSpec: EthSpec> NetworkGlobals<TSpec> {
-    pub fn new(enr: Enr, tcp_port: u16, udp_port: u16, log: &slog::Logger) -> Self {
+    pub fn new(
+        enr: Enr,
+        tcp_port: u16,
+        udp_port: u16,
+        local_metadata: MetaData<TSpec>,
+        trusted_peers: Vec<PeerId>,
+        log: &slog::Logger,
+    ) -> Self {
        NetworkGlobals {
            local_enr: RwLock::new(enr.clone()),
            peer_id: RwLock::new(enr.peer_id()),
            listen_multiaddrs: RwLock::new(Vec::new()),
            listen_port_tcp: AtomicU16::new(tcp_port),
            listen_port_udp: AtomicU16::new(udp_port),
-            peers: RwLock::new(PeerDB::new(log)),
+            local_metadata: RwLock::new(local_metadata),
+            peers: RwLock::new(PeerDB::new(trusted_peers, log)),
            gossipsub_subscriptions: RwLock::new(HashSet::new()),
            sync_state: RwLock::new(SyncState::Stalled),
        }
--- a/beacon_node/network/src/attestation_service/tests/mod.rs
+++ b/beacon_node/network/src/attestation_service/tests/mod.rs
@@ -8,6 +8,8 @@ mod tests {
        migrate::NullMigrator,
    };
    use eth2_libp2p::discovery::{build_enr, Keypair};
+    use eth2_libp2p::rpc::methods::MetaData;
+    use eth2_libp2p::types::EnrBitfield;
    use eth2_libp2p::{
        discovery::CombinedKey, CombinedKeyExt, NetworkConfig, NetworkGlobals, SubnetDiscovery,
    };
@@ -102,7 +104,14 @@ mod tests {
        let enr_key = CombinedKey::from_libp2p(&Keypair::generate_secp256k1()).unwrap();
        let enr = build_enr::<MinimalEthSpec>(&enr_key, &config, EnrForkId::default()).unwrap();

-        let network_globals: NetworkGlobals<MinimalEthSpec> = NetworkGlobals::new(enr, 0, 0, &log);
+        // Default metadata
+        let meta_data = MetaData {
+            seq_number: 0,
+            attnets: EnrBitfield::<MinimalEthSpec>::default(),
+        };
+
+        let network_globals: NetworkGlobals<MinimalEthSpec> =
+            NetworkGlobals::new(enr, 0, 0, meta_data, vec![], &log);
        AttestationService::new(beacon_chain, Arc::new(network_globals), &log)
    }

--- a/beacon_node/src/cli.rs
+++ b/beacon_node/src/cli.rs
@@ -131,7 +131,13 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                .help("Disables the discv5 discovery protocol. The node will not search for new peers or participate in the discovery protocol.")
                .takes_value(false),
        )
-
+        .arg(
+            Arg::with_name("trusted-peers")
+                .long("trusted-peers")
+                .value_name("TRUSTED_PEERS")
+                .help("One or more comma-delimited trusted peer ids which always have the highest score according to the peer scoring system.")
+                .takes_value(true),
+        )
        /* REST API related arguments */
        .arg(
            Arg::with_name("http")
--- a/beacon_node/src/config.rs
+++ b/beacon_node/src/config.rs
@@ -2,7 +2,7 @@ use beacon_chain::builder::PUBKEY_CACHE_FILENAME;
 use clap::ArgMatches;
 use clap_utils::BAD_TESTNET_DIR_MESSAGE;
 use client::{config::DEFAULT_DATADIR, ClientConfig, ClientGenesis};
-use eth2_libp2p::{multiaddr::Protocol, Enr, Multiaddr, NetworkConfig};
+use eth2_libp2p::{multiaddr::Protocol, Enr, Multiaddr, NetworkConfig, PeerIdSerialized};
 use eth2_testnet_config::Eth2TestnetConfig;
 use slog::{crit, info, Logger};
 use ssz::Encode;
@@ -343,6 +343,17 @@ pub fn set_network_config(
            .collect::<Result<Vec<Multiaddr>, _>>()?;
    }

+    if let Some(trusted_peers_str) = cli_args.value_of("trusted-peers") {
+        config.trusted_peers = trusted_peers_str
+            .split(',')
+            .map(|peer_id| {
+                peer_id
+                    .parse()
+                    .map_err(|_| format!("Invalid trusted peer id: {}", peer_id))
+            })
+            .collect::<Result<Vec<PeerIdSerialized>, _>>()?;
+    }
+
    if let Some(enr_udp_port_str) = cli_args.value_of("enr-udp-port") {
        config.enr_udp_port = Some(
            enr_udp_port_str
--- a/beacon_node/store/Cargo.toml
+++ b/beacon_node/store/Cargo.toml
@@ -15,7 +15,7 @@ rayon = "1.3.0"

 [dependencies]
 db-key = "0.0.5"
-leveldb = "0.8.5"
+leveldb = "0.8.6"
 parking_lot = "0.11.0"
 itertools = "0.9.0"
 eth2_ssz = "0.1.2"
--- a/book/src/cross-compiling.md
+++ b/book/src/cross-compiling.md
@@ -18,17 +18,15 @@ project.

 The `Makefile` in the project contains four targets for cross-compiling:

- `build-x86_64`: builds an optimized version for x86_64 processors (suitable
-	for most users).
- `build-x86_64-portable`: builds a version x86_64 processors which avoids
-	using some modern CPU instructions that might cause an "illegal
-	instruction" error on older CPUs.
- `build-aarch64`: builds an optimized version for 64bit ARM processors
+- `build-x86_64`: builds an optimized version for x86_64 processors (suitable for most users).
+  Supports Intel Broadwell (2014) and newer, and AMD Ryzen (2017) and newer.
+- `build-x86_64-portable`: builds a version for x86_64 processors which avoids using some modern CPU
+  instructions that are incompatible with older CPUs. Suitable for pre-Broadwell/Ryzen CPUs.
+- `build-aarch64`: builds an optimized version for 64-bit ARM processors
 	(suitable for Raspberry Pi 4).
- `build-aarch64-portable`: builds a version 64 bit ARM processors which avoids
-	using some modern CPU instructions that might cause an "illegal
-	instruction" error on older CPUs.
-
+- `build-aarch64-portable`: builds a version for 64-bit ARM processors which avoids using some
+  modern CPU instructions. In practice, very few ARM processors lack the instructions necessary to
+  run the faster non-portable build.

 ### Example

--- a/boot_node/Cargo.toml
+++ b/boot_node/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "boot_node"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Sigma Prime <contact@sigmaprime.io>"]
 edition = "2018"

--- a/common/lighthouse_version/src/lib.rs
+++ b/common/lighthouse_version/src/lib.rs
@@ -10,7 +10,7 @@ use target_info::Target;
 /// `Lighthouse/v0.2.0-1419501f2+`
 pub const VERSION: &str = git_version!(
    args = ["--always", "--dirty=+"],
-    prefix = "Lighthouse/v0.2.10-",
+    prefix = "Lighthouse/v0.2.11-",
    fallback = "unknown"
 );

--- a/consensus/fork_choice/src/fork_choice.rs
+++ b/consensus/fork_choice/src/fork_choice.rs
@@ -3,7 +3,8 @@ use std::marker::PhantomData;
 use proto_array::{Block as ProtoBlock, ProtoArrayForkChoice};
 use ssz_derive::{Decode, Encode};
 use types::{
-    BeaconBlock, BeaconState, BeaconStateError, Epoch, EthSpec, Hash256, IndexedAttestation, Slot,
+    BeaconBlock, BeaconState, BeaconStateError, Checkpoint, Epoch, EthSpec, Hash256,
+    IndexedAttestation, Slot,
 };

 use crate::ForkChoiceStore;
@@ -758,6 +759,11 @@ where
            .is_descendant(self.fc_store.finalized_checkpoint().root, block_root)
    }

+    /// Return the current finalized checkpoint.
+    pub fn finalized_checkpoint(&self) -> Checkpoint {
+        *self.fc_store.finalized_checkpoint()
+    }
+
    /// Returns the latest message for a given validator, if any.
    ///
    /// Returns `(block_root, block_slot)`.
--- a/consensus/safe_arith/src/iter.rs
+++ b/consensus/safe_arith/src/iter.rs
@@ -0,0 +1,70 @@
+use crate::{Result, SafeArith};
+
+/// Extension trait for iterators, providing a safe replacement for `sum`.
+pub trait SafeArithIter<T> {
+    fn safe_sum(self) -> Result<T>;
+}
+
+impl<I, T> SafeArithIter<T> for I
+where
+    I: Iterator<Item = T> + Sized,
+    T: SafeArith,
+{
+    fn safe_sum(mut self) -> Result<T> {
+        self.try_fold(T::ZERO, |acc, x| acc.safe_add(x))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::ArithError;
+
+    #[test]
+    fn empty_sum() {
+        let v: Vec<u64> = vec![];
+        assert_eq!(v.into_iter().safe_sum(), Ok(0));
+    }
+
+    #[test]
+    fn unsigned_sum_small() {
+        let v = vec![400u64, 401, 402, 403, 404, 405, 406];
+        assert_eq!(
+            v.iter().copied().safe_sum().unwrap(),
+            v.iter().copied().sum()
+        );
+    }
+
+    #[test]
+    fn unsigned_sum_overflow() {
+        let v = vec![u64::MAX, 1];
+        assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
+    }
+
+    #[test]
+    fn signed_sum_small() {
+        let v = vec![-1i64, -2i64, -3i64, 3, 2, 1];
+        assert_eq!(v.into_iter().safe_sum(), Ok(0));
+    }
+
+    #[test]
+    fn signed_sum_overflow_above() {
+        let v = vec![1, 2, 3, 4, i16::MAX, 0, 1, 2, 3];
+        assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
+    }
+
+    #[test]
+    fn signed_sum_overflow_below() {
+        let v = vec![i16::MIN, -1];
+        assert_eq!(v.into_iter().safe_sum(), Err(ArithError::Overflow));
+    }
+
+    #[test]
+    fn signed_sum_almost_overflow() {
+        let v = vec![i64::MIN, 1, -1i64, i64::MAX, i64::MAX, 1];
+        assert_eq!(
+            v.iter().copied().safe_sum().unwrap(),
+            v.iter().copied().sum()
+        );
+    }
+}
--- a/consensus/safe_arith/src/lib.rs
+++ b/consensus/safe_arith/src/lib.rs
@@ -1,4 +1,7 @@
 //! Library for safe arithmetic on integers, avoiding overflow and division by zero.
+mod iter;
+
+pub use iter::SafeArithIter;

 /// Error representing the failure of an arithmetic operation.
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
@@ -7,7 +10,7 @@ pub enum ArithError {
    DivisionByZero,
 }

-type Result<T> = std::result::Result<T, ArithError>;
+pub type Result<T> = std::result::Result<T, ArithError>;

 macro_rules! assign_method {
    ($name:ident, $op:ident, $doc_op:expr) => {
--- a/consensus/state_processing/src/per_epoch_processing/process_slashings.rs
+++ b/consensus/state_processing/src/per_epoch_processing/process_slashings.rs
@@ -1,4 +1,4 @@
-use safe_arith::SafeArith;
+use safe_arith::{SafeArith, SafeArithIter};
 use types::{BeaconStateError as Error, *};

 /// Process slashings.
@@ -10,7 +10,7 @@ pub fn process_slashings<T: EthSpec>(
    spec: &ChainSpec,
 ) -> Result<(), Error> {
    let epoch = state.current_epoch();
-    let sum_slashings = state.get_all_slashings().iter().sum::<u64>();
+    let sum_slashings = state.get_all_slashings().iter().copied().safe_sum()?;

    for (index, validator) in state.validators.iter().enumerate() {
        if validator.slashed
--- a/crypto/bls/Cargo.toml
+++ b/crypto/bls/Cargo.toml
@@ -17,7 +17,7 @@ eth2_hashing = "0.1.0"
 ethereum-types = "0.9.1"
 arbitrary = { version = "0.4.4", features = ["derive"], optional = true }
 zeroize = { version = "1.0.0", features = ["zeroize_derive"] }
-blst = { git = "https://github.com/sigp/blst.git", rev = "284f7059642851c760a09fb1708bcb59c7ca323c" }
+blst = { git = "https://github.com/supranational/blst.git", rev = "a8398ed284b0d78858302ad1ceb25a80e7bbe535" }

 [features]
 default = ["supranational"]
@@ -25,3 +25,4 @@ fake_crypto = []
 milagro = []
 supranational = []
 supranational-portable = ["supranational", "blst/portable"]
+supranational-force-adx = ["supranational", "blst/force-adx"]
--- a/lcli/Cargo.toml
+++ b/lcli/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "lcli"
 description = "Lighthouse CLI (modeled after zcli)"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = "2018"

--- a/lighthouse/Cargo.toml
+++ b/lighthouse/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "lighthouse"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Sigma Prime <contact@sigmaprime.io>"]
 edition = "2018"

@@ -9,6 +9,9 @@ edition = "2018"
 write_ssz_files = ["beacon_node/write_ssz_files"]
 # Compiles the BLS crypto code so that the binary is portable across machines.
 portable = ["bls/supranational-portable"]
+# Compiles BLST so that it always uses ADX instructions.
+# Compatible with processors from 2013 onwards.
+modern = ["bls/supranational-force-adx"]
 # Uses the slower Milagro BLS library, which is written in native Rust.
 milagro = ["bls/milagro"]

--- a/lighthouse/src/main.rs
+++ b/lighthouse/src/main.rs
@@ -16,6 +16,8 @@ pub const ETH2_CONFIG_FILENAME: &str = "eth2-spec.toml";
 fn bls_library_name() -> &'static str {
    if cfg!(feature = "portable") {
        "blst-portable"
+    } else if cfg!(feature = "modern") {
+        "blst-modern"
    } else if cfg!(feature = "milagro") {
        "milagro"
    } else {
@@ -181,6 +183,13 @@ fn run<E: EthSpec>(
        ));
    }

+    #[cfg(all(feature = "modern", target_arch = "x86_64"))]
+    if !std::is_x86_feature_detected!("adx") {
+        return Err(format!(
+            "CPU incompatible with optimized binary, please try Lighthouse portable build"
+        ));
+    }
+
    let debug_level = matches
        .value_of("debug-level")
        .ok_or_else(|| "Expected --debug-level flag".to_string())?;
--- a/validator_client/Cargo.toml
+++ b/validator_client/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "validator_client"
-version = "0.2.10"
+version = "0.2.11"
 authors = ["Paul Hauner <paul@paulhauner.com>", "Age Manning <Age@AgeManning.com>", "Luke Anderson <luke@lukeanderson.com.au>"]
 edition = "2018"
Author	SHA1	Message	Date
Michael Sproul	7aceff4d13	Add `safe_sum` and use it in state_processing (#1620 ) ## Issue Addressed Closes #1098 ## Proposed Changes Add a `SafeArithIter` trait with a `safe_sum` method, and use it in `state_processing`. This seems to be the only place in `consensus` where it is relevant -- i.e. where we were using `sum` and the integer_arith lint is enabled. ## Additional Info This PR doesn't include any Clippy linting to prevent `sum` from being called. It seems there is no existing Clippy lint that suits our purpose, but I'm going to look into that and maybe schedule writing one as a lower-priority task. This theoretically _is_ a consensus breaking change, but it shouldn't impact Medalla (or any other testnet) because `slashings` shouldn't overflow!	2020-09-22 05:40:04 +00:00
Michael Sproul	4fca306397	Update BLST, add force-adx support (#1595 ) ## Issue Addressed Closes #1504 Closes https://github.com/sigp/lighthouse/issues/1505 ## Proposed Changes * Update `blst` to the latest version, which is more portable and includes finer-grained compilation controls (see below). * Detect the case where a binary has been explicitly compiled with ADX support but it's missing at runtime, and report a nicer error than `SIGILL`. ## Known Issues * None. The previous issue with `make build-aarch64` (https://github.com/supranational/blst/issues/27), has been resolved. ## Additional Info I think we should tweak our release process and our Docker builds so that we provide two options: Binaries: * `lighthouse`: compiled with `modern`/`force-adx`, for CPUs 2013 and newer * `lighthouse-portable`: compiled with `portable` for older CPUs Docker images: * `sigp/lighthouse:latest`: multi-arch image with `modern` x86_64 and vanilla aarch64 binary * `sigp/lighthouse:latest-portable`: multi-arch image with `portable` builds for x86_64 and aarch64 And relevant Docker images for the releases (as per https://github.com/sigp/lighthouse/pull/1574#issuecomment-687766141), tagged `v0.x.y` and `v0.x.y-portable`	2020-09-22 05:40:02 +00:00
Paul Hauner	d85d5a435e	Bump to v0.2.11 (#1645 ) ## Issue Addressed NA ## Proposed Changes - Bump version to v0.2.11 - Run `cargo update`. ## Additional Info NA	2020-09-22 04:45:15 +00:00
Paul Hauner	bd39cc8e26	Apply hotfix for inconsistent head (#1639 ) ## Issue Addressed - Resolves #1616 ## Proposed Changes If we look at the function which persists fork choice and the canonical head to disk: `1db8daae0c/beacon_node/beacon_chain/src/beacon_chain.rs (L234-L280)` There is a race-condition which might cause the canonical head and fork choice values to be out-of-sync. I believe this is the cause of #1616. I managed to recreate the issue and produce a database that was unable to sync under the `master` branch but able to sync with this branch. These new changes solve the issue by ignoring the persisted `canonical_head_block_root` value and instead getting fork choice to generate it. This ensures that the canonical head is in-sync with fork choice. ## Additional Info This is hotfix method that leaves some crusty code hanging around. Once this PR is merged (to satisfy the v0.2.x users) we should later update and merge #1638 so we can have a clean fix for the v0.3.x versions.	2020-09-22 02:06:10 +00:00
Pawan Dhananjay	14ff38539c	Add trusted peers (#1640 ) ## Issue Addressed Closes #1581 ## Proposed Changes Adds a new cli option for trusted peers who always have the maximum possible score.	2020-09-22 01:12:36 +00:00
Michael Sproul	5d17eb899f	Update LevelDB to v0.8.6, removing patch (#1636 ) Removes our dependency on a fork of LevelDB now that https://github.com/skade/leveldb-sys/pull/17 is merged	2020-09-21 11:53:53 +00:00
Age Manning	1db8daae0c	Shift metadata to the global network variables (#1631 ) ## Issue Addressed N/A ## Proposed Changes Shifts the local `metadata` to `network_globals` making it accessible to the HTTP API and other areas of lighthouse. ## Additional Info N/A	2020-09-21 02:00:38 +00:00
Pawan Dhananjay	7b97c4ad30	Snappy additional sanity checks (#1625 ) ## Issue Addressed N/A ## Proposed Changes Adds the following check from the spec > A reader SHOULD NOT read more than max_encoded_len(n) bytes after reading the SSZ length-prefix n from the header.	2020-09-21 01:06:25 +00:00