Native support for Gnosis Beacon Chain network (#2931)

## Proposed Changes

Add a new hardcoded spec for the Gnosis Beacon Chain.
Ideally, official Lighthouse executables will be able to connect to the gnosis beacon chain from now on, using `--network gnosis` CLI option.

.github/workflows/release.yml

@@ -181,19 +181,19 @@ jobs:
 
             - name: Build Lighthouse for x86_64-apple-darwin portable
               if:   matrix.arch == 'x86_64-apple-darwin-portable'
-              run:  cargo install --path lighthouse --force --locked --features portable
+              run:  cargo install --path lighthouse --force --locked --features portable,gnosis
 
             - name: Build Lighthouse for x86_64-apple-darwin modern
               if:   matrix.arch == 'x86_64-apple-darwin'
-              run:  cargo install --path lighthouse --force --locked --features modern
+              run:  cargo install --path lighthouse --force --locked --features modern,gnosis
 
             - name: Build Lighthouse for Windows portable
               if:   matrix.arch == 'x86_64-windows-portable'
-              run:  cargo install --path lighthouse --force --locked --features portable
+              run:  cargo install --path lighthouse --force --locked --features portable,gnosis
 
             - name: Build Lighthouse for Windows modern
               if:   matrix.arch == 'x86_64-windows'
-              run:  cargo install --path lighthouse --force --locked --features modern
+              run:  cargo install --path lighthouse --force --locked --features modern,gnosis
 
             - name: Configure GPG and create artifacts
               if: startsWith(matrix.arch, 'x86_64-windows') != true

Makefile

@@ -50,13 +50,13 @@ endif
 # optimized CPU functions that may not be available on some systems. This
 # results in a more portable binary with ~20% slower BLS verification.
 build-x86_64:
-	cross build --release --manifest-path lighthouse/Cargo.toml --target x86_64-unknown-linux-gnu --features modern
+	cross build --release --manifest-path lighthouse/Cargo.toml --target x86_64-unknown-linux-gnu --features modern,gnosis
 build-x86_64-portable:
-	cross build --release --manifest-path lighthouse/Cargo.toml --target x86_64-unknown-linux-gnu --features portable
+	cross build --release --manifest-path lighthouse/Cargo.toml --target x86_64-unknown-linux-gnu --features portable,gnosis
 build-aarch64:
-	cross build --release --manifest-path lighthouse/Cargo.toml --target aarch64-unknown-linux-gnu
+	cross build --release --manifest-path lighthouse/Cargo.toml --target aarch64-unknown-linux-gnu --features gnosis
 build-aarch64-portable:
-	cross build --release --manifest-path lighthouse/Cargo.toml --target aarch64-unknown-linux-gnu --features portable
+	cross build --release --manifest-path lighthouse/Cargo.toml --target aarch64-unknown-linux-gnu --features portable,gnosis
 
 # Create a `.tar.gz` containing a binary for a specific target.
 define tarball_release_binary

boot_node/src/lib.rs

@@ -63,6 +63,9 @@ pub fn run(
         EthSpecId::Mainnet => {
             main::<types::MainnetEthSpec>(lh_matches, bn_matches, eth2_network_config, log)
         }
+        EthSpecId::Gnosis => {
+            main::<types::GnosisEthSpec>(lh_matches, bn_matches, eth2_network_config, log)
+        }
     } {
         slog::crit!(slog_scope::logger(), "{}", e);
     }

common/eth2_config/src/lib.rs

@@ -53,6 +53,13 @@ impl Eth2Config {
             spec: ChainSpec::minimal(),
         }
     }
+
+    pub fn gnosis() -> Self {
+        Self {
+            eth_spec_id: EthSpecId::Gnosis,
+            spec: ChainSpec::gnosis(),
+        }
+    }
 }
 
 /// A directory that can be built by downloading files via HTTP.
@@ -229,5 +236,6 @@ macro_rules! define_hardcoded_nets {
 define_hardcoded_nets!(
     (mainnet, "mainnet", GENESIS_STATE_IS_KNOWN),
     (pyrmont, "pyrmont", GENESIS_STATE_IS_KNOWN),
-    (prater, "prater", GENESIS_STATE_IS_KNOWN)
+    (prater, "prater", GENESIS_STATE_IS_KNOWN),
+    (gnosis, "gnosis", GENESIS_STATE_IS_KNOWN)
 );

common/eth2_network_config/built_in_network_configs/gnosis/boot_enr.yaml

@@ -0,0 +1,5 @@
+# Gnosis Chain Team
+- enr:-IS4QGmLwm7gFd0L0CEisllrb1op3v-wAGSc7_pwSMGgN3bOS9Fz7m1dWbwuuPHKqeETz9MbhjVuoWk0ohkyRv98kVoBgmlkgnY0gmlwhGjtlgaJc2VjcDI1NmsxoQLMdh0It9fJbuiLydZ9fpF6MRzgNle0vODaDiMqhbC7WIN1ZHCCIyg
+- enr:-IS4QFUVG3dvLPCUEI7ycRvFm0Ieg_ITa5tALmJ9LI7dJ6ieT3J4fF9xLRjOoB4ApV-Rjp7HeLKzyTWG1xRdbFBNZPQBgmlkgnY0gmlwhErP5weJc2VjcDI1NmsxoQOBbaJBvx0-w_pyZUhQl9A510Ho2T0grE0K8JevzES99IN1ZHCCIyg
+- enr:-Ku4QOQk8V-Hu2gxFzRXmLYIO4AvWDZhoMFwTf3n3DYm_mbsWv0ZitoqiN6JZUUj6Li6e1Jk1w2zFSVHKPMUP1g5tsgBh2F0dG5ldHOIAAAAAAAAAACEZXRoMpD5Jd3FAAAAZP__________gmlkgnY0gmlwhC1PTpmJc2VjcDI1NmsxoQL1Ynt5PoA0UOcHa1Rfn98rmnRlLzNuWTePPP4m4qHVroN1ZHCCKvg
+- enr:-Ku4QFaTwgoms-EiiRIfHUH3FXprWUFgjHg4UuWvilqoUQtDbmTszVIxUEOwQUmA2qkiP-T9wXjc_rVUuh9cU7WgwbgBh2F0dG5ldHOIAAAAAAAAAACEZXRoMpD5Jd3FAAAAZP__________gmlkgnY0gmlwhC0hBmCJc2VjcDI1NmsxoQOpsg1XCrXmCwZKcSTcycLwldoKUMHPUpMEVGeg_EEhuYN1ZHCCKvg

common/eth2_network_config/built_in_network_configs/gnosis/config.yaml

@@ -0,0 +1,85 @@
+# Gnosis Beacon Chain config
+
+# Extends the gnosis preset
+PRESET_BASE: 'gnosis'
+
+# Transition
+# ---------------------------------------------------------------
+# TBD, 2**256-2**10 is a placeholder
+TERMINAL_TOTAL_DIFFICULTY: 115792089237316195423570985008687907853269984665640564039457584007913129638912
+# By default, don't use these params
+TERMINAL_BLOCK_HASH: 0x0000000000000000000000000000000000000000000000000000000000000000
+TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH: 18446744073709551615
+
+# Genesis
+# ---------------------------------------------------------------
+# `2**12` (= 4,096)
+MIN_GENESIS_ACTIVE_VALIDATOR_COUNT: 4096
+# Dec 8, 2021, 13:00 UTC
+MIN_GENESIS_TIME: 1638968400
+# Gnosis Beacon Chain initial fork version
+GENESIS_FORK_VERSION: 0x00000064
+# 6000 seconds (100 minutes)
+GENESIS_DELAY: 6000
+
+
+# Forking
+# ---------------------------------------------------------------
+# Some forks are disabled for now:
+#  - These may be re-assigned to another fork-version later
+#  - Temporarily set to max uint64 value: 2**64 - 1
+
+# Altair
+ALTAIR_FORK_VERSION: 0x01000064
+ALTAIR_FORK_EPOCH: 512
+# Merge
+BELLATRIX_FORK_VERSION: 0x02000064
+BELLATRIX_FORK_EPOCH: 18446744073709551615
+# Sharding
+SHARDING_FORK_VERSION: 0x03000064
+SHARDING_FORK_EPOCH: 18446744073709551615
+
+# TBD, 2**32 is a placeholder. Merge transition approach is in active R&D.
+TRANSITION_TOTAL_DIFFICULTY: 4294967296
+
+
+# Time parameters
+# ---------------------------------------------------------------
+# 5 seconds
+SECONDS_PER_SLOT: 5
+# 6 (estimate from Gnosis Chain)
+SECONDS_PER_ETH1_BLOCK: 6
+# 2**8 (= 256) epochs ~8 hours
+MIN_VALIDATOR_WITHDRAWABILITY_DELAY: 256
+# 2**8 (= 256) epochs ~8 hours
+SHARD_COMMITTEE_PERIOD: 256
+# 2**10 (= 1024) ~1.4 hour
+ETH1_FOLLOW_DISTANCE: 1024
+
+
+# Validator cycle
+# ---------------------------------------------------------------
+# 2**2 (= 4)
+INACTIVITY_SCORE_BIAS: 4
+# 2**4 (= 16)
+INACTIVITY_SCORE_RECOVERY_RATE: 16
+# 2**4 * 10**9 (= 16,000,000,000) Gwei
+EJECTION_BALANCE: 16000000000
+# 2**2 (= 4)
+MIN_PER_EPOCH_CHURN_LIMIT: 4
+# 2**12 (= 4096)
+CHURN_LIMIT_QUOTIENT: 4096
+
+
+# Fork choice
+# ---------------------------------------------------------------
+# TODO: enable once proposer boosting is desired on mainnet
+# 70%
+# PROPOSER_SCORE_BOOST: 70
+
+# Deposit contract
+# ---------------------------------------------------------------
+# Gnosis Chain
+DEPOSIT_CHAIN_ID: 100
+DEPOSIT_NETWORK_ID: 100
+DEPOSIT_CONTRACT_ADDRESS: 0x0B98057eA310F4d31F2a452B414647007d1645d9

common/eth2_network_config/built_in_network_configs/gnosis/deploy_block.txt

@@ -0,0 +1 @@
+19469077

common/eth2_network_config/src/lib.rs

@@ -226,7 +226,7 @@ mod tests {
     use super::*;
     use ssz::Encode;
     use tempfile::Builder as TempBuilder;
-    use types::{Config, Eth1Data, Hash256, MainnetEthSpec};
+    use types::{Config, Eth1Data, GnosisEthSpec, Hash256, MainnetEthSpec, GNOSIS};
 
     type E = MainnetEthSpec;
 
@@ -263,7 +263,11 @@ mod tests {
                 .unwrap_or_else(|_| panic!("{:?}", net.name));
 
             // Ensure we can parse the YAML config to a chain spec.
-            config.chain_spec::<MainnetEthSpec>().unwrap();
+            if net.name == GNOSIS {
+                config.chain_spec::<GnosisEthSpec>().unwrap();
+            } else {
+                config.chain_spec::<MainnetEthSpec>().unwrap();
+            }
 
             assert_eq!(
                 config.genesis_state_bytes.is_some(),

consensus/types/presets/gnosis/altair.yaml

@@ -0,0 +1,24 @@
+# Gnosis Beacon Chain preset - Altair
+
+# Updated penalty values
+# ---------------------------------------------------------------
+# 3 * 2**24 (= 50,331,648)
+INACTIVITY_PENALTY_QUOTIENT_ALTAIR: 50331648
+# 2**6 (= 64)
+MIN_SLASHING_PENALTY_QUOTIENT_ALTAIR: 64
+# 2
+PROPORTIONAL_SLASHING_MULTIPLIER_ALTAIR: 2
+
+
+# Sync committee
+# ---------------------------------------------------------------
+# 2**9 (= 512)
+SYNC_COMMITTEE_SIZE: 512
+# 2**8 (= 256)
+EPOCHS_PER_SYNC_COMMITTEE_PERIOD: 512
+
+
+# Sync protocol
+# ---------------------------------------------------------------
+# 1
+MIN_SYNC_COMMITTEE_PARTICIPANTS: 1

consensus/types/presets/gnosis/bellatrix.yaml

@@ -0,0 +1,21 @@
+# Gnosis Beacon Chain preset - Bellatrix
+
+# Updated penalty values
+# ---------------------------------------------------------------
+# 2**24 (= 16,777,216)
+INACTIVITY_PENALTY_QUOTIENT_BELLATRIX: 16777216
+# 2**5 (= 32)
+MIN_SLASHING_PENALTY_QUOTIENT_BELLATRIX: 32
+# 3
+PROPORTIONAL_SLASHING_MULTIPLIER_BELLATRIX: 3
+
+# Execution
+# ---------------------------------------------------------------
+# 2**30 (= 1,073,741,824)
+MAX_BYTES_PER_TRANSACTION: 1073741824
+# 2**20 (= 1,048,576)
+MAX_TRANSACTIONS_PER_PAYLOAD: 1048576
+# 2**8 (= 256)
+BYTES_PER_LOGS_BLOOM: 256
+# 2**5 (= 32)
+MAX_EXTRA_DATA_BYTES: 32

consensus/types/presets/gnosis/phase0.yaml

@@ -0,0 +1,94 @@
+# Gnosis Beacon Chain preset - Phase0
+
+# Misc
+# ---------------------------------------------------------------
+# 2**6 (= 64)
+MAX_COMMITTEES_PER_SLOT: 64
+# 2**7 (= 128)
+TARGET_COMMITTEE_SIZE: 128
+# 2**11 (= 2,048)
+MAX_VALIDATORS_PER_COMMITTEE: 2048
+# See issue 563
+SHUFFLE_ROUND_COUNT: 90
+# 4
+HYSTERESIS_QUOTIENT: 4
+# 1 (minus 0.25)
+HYSTERESIS_DOWNWARD_MULTIPLIER: 1
+# 5 (plus 1.25)
+HYSTERESIS_UPWARD_MULTIPLIER: 5
+
+
+# Fork Choice
+# ---------------------------------------------------------------
+# 2**3 (= 8)
+SAFE_SLOTS_TO_UPDATE_JUSTIFIED: 8
+
+
+# Gwei values
+# ---------------------------------------------------------------
+# 2**0 * 10**9 (= 1,000,000,000) Gwei
+MIN_DEPOSIT_AMOUNT: 1000000000
+# 2**5 * 10**9 (= 32,000,000,000) Gwei
+MAX_EFFECTIVE_BALANCE: 32000000000
+# 2**0 * 10**9 (= 1,000,000,000) Gwei
+EFFECTIVE_BALANCE_INCREMENT: 1000000000
+
+
+# Time parameters
+# ---------------------------------------------------------------
+# 2**0 (= 1) slots 5 seconds
+MIN_ATTESTATION_INCLUSION_DELAY: 1
+# 2**4 (= 16) slots 1.87 minutes
+SLOTS_PER_EPOCH: 16
+# 2**0 (= 1) epochs 1.87 minutes
+MIN_SEED_LOOKAHEAD: 1
+# 2**2 (= 4) epochs 7.47 minutes
+MAX_SEED_LOOKAHEAD: 4
+# 2**6 (= 64) epochs ~2 hours
+EPOCHS_PER_ETH1_VOTING_PERIOD: 64
+# 2**13 (= 8,192) slots ~15.9 hours
+SLOTS_PER_HISTORICAL_ROOT: 8192
+# 2**2 (= 4) epochs 7.47 minutes
+MIN_EPOCHS_TO_INACTIVITY_PENALTY: 4
+
+
+# State list lengths
+# ---------------------------------------------------------------
+# 2**16 (= 65,536) epochs ~85 days
+EPOCHS_PER_HISTORICAL_VECTOR: 65536
+# 2**13 (= 8,192) epochs ~10.6 days
+EPOCHS_PER_SLASHINGS_VECTOR: 8192
+# 2**24 (= 16,777,216) historical roots, ~15,243 years
+HISTORICAL_ROOTS_LIMIT: 16777216
+# 2**40 (= 1,099,511,627,776) validator spots
+VALIDATOR_REGISTRY_LIMIT: 1099511627776
+
+
+# Reward and penalty quotients
+# ---------------------------------------------------------------
+# 2**6 (= 64)
+BASE_REWARD_FACTOR: 25
+# 2**9 (= 512)
+WHISTLEBLOWER_REWARD_QUOTIENT: 512
+# 2**3 (= 8)
+PROPOSER_REWARD_QUOTIENT: 8
+# 2**26 (= 67,108,864)
+INACTIVITY_PENALTY_QUOTIENT: 67108864
+# 2**7 (= 128) (lower safety margin at Phase 0 genesis)
+MIN_SLASHING_PENALTY_QUOTIENT: 128
+# 1 (lower safety margin at Phase 0 genesis)
+PROPORTIONAL_SLASHING_MULTIPLIER: 1
+
+
+# Max operations per block
+# ---------------------------------------------------------------
+# 2**4 (= 16)
+MAX_PROPOSER_SLASHINGS: 16
+# 2**1 (= 2)
+MAX_ATTESTER_SLASHINGS: 2
+# 2**7 (= 128)
+MAX_ATTESTATIONS: 128
+# 2**4 (= 16)
+MAX_DEPOSITS: 16
+# 2**4 (= 16)
+MAX_VOLUNTARY_EXITS: 16

consensus/types/src/chain_spec.rs

@@ -596,6 +596,161 @@ impl ChainSpec {
             ..ChainSpec::mainnet()
         }
     }
+
+    /// Returns a `ChainSpec` compatible with the Gnosis Beacon Chain specification.
+    pub fn gnosis() -> Self {
+        Self {
+            /*
+             * Constants
+             */
+            genesis_slot: Slot::new(0),
+            far_future_epoch: Epoch::new(u64::MAX),
+            base_rewards_per_epoch: 4,
+            deposit_contract_tree_depth: 32,
+
+            /*
+             * Misc
+             */
+            max_committees_per_slot: 64,
+            target_committee_size: 128,
+            min_per_epoch_churn_limit: 4,
+            churn_limit_quotient: 4_096,
+            shuffle_round_count: 90,
+            min_genesis_active_validator_count: 4_096,
+            min_genesis_time: 1638968400, // Dec 8, 2020
+            hysteresis_quotient: 4,
+            hysteresis_downward_multiplier: 1,
+            hysteresis_upward_multiplier: 5,
+
+            /*
+             *  Gwei values
+             */
+            min_deposit_amount: option_wrapper(|| {
+                u64::checked_pow(2, 0)?.checked_mul(u64::checked_pow(10, 9)?)
+            })
+            .expect("calculation does not overflow"),
+            max_effective_balance: option_wrapper(|| {
+                u64::checked_pow(2, 5)?.checked_mul(u64::checked_pow(10, 9)?)
+            })
+            .expect("calculation does not overflow"),
+            ejection_balance: option_wrapper(|| {
+                u64::checked_pow(2, 4)?.checked_mul(u64::checked_pow(10, 9)?)
+            })
+            .expect("calculation does not overflow"),
+            effective_balance_increment: option_wrapper(|| {
+                u64::checked_pow(2, 0)?.checked_mul(u64::checked_pow(10, 9)?)
+            })
+            .expect("calculation does not overflow"),
+
+            /*
+             * Initial Values
+             */
+            genesis_fork_version: [0x00, 0x00, 0x00, 0x64],
+            bls_withdrawal_prefix_byte: 0,
+
+            /*
+             * Time parameters
+             */
+            genesis_delay: 6000, // 100 minutes
+            seconds_per_slot: 5,
+            min_attestation_inclusion_delay: 1,
+            min_seed_lookahead: Epoch::new(1),
+            max_seed_lookahead: Epoch::new(4),
+            min_epochs_to_inactivity_penalty: 4,
+            min_validator_withdrawability_delay: Epoch::new(256),
+            shard_committee_period: 256,
+
+            /*
+             * Reward and penalty quotients
+             */
+            base_reward_factor: 25,
+            whistleblower_reward_quotient: 512,
+            proposer_reward_quotient: 8,
+            inactivity_penalty_quotient: u64::checked_pow(2, 26).expect("pow does not overflow"),
+            min_slashing_penalty_quotient: 128,
+            proportional_slashing_multiplier: 1,
+
+            /*
+             * Signature domains
+             */
+            domain_beacon_proposer: 0,
+            domain_beacon_attester: 1,
+            domain_randao: 2,
+            domain_deposit: 3,
+            domain_voluntary_exit: 4,
+            domain_selection_proof: 5,
+            domain_aggregate_and_proof: 6,
+
+            /*
+             * Fork choice
+             */
+            safe_slots_to_update_justified: 8,
+            proposer_score_boost: None,
+
+            /*
+             * Eth1
+             */
+            eth1_follow_distance: 1024,
+            seconds_per_eth1_block: 6,
+            deposit_chain_id: 100,
+            deposit_network_id: 100,
+            deposit_contract_address: "0B98057eA310F4d31F2a452B414647007d1645d9"
+                .parse()
+                .expect("chain spec deposit contract address"),
+
+            /*
+             * Altair hard fork params
+             */
+            inactivity_penalty_quotient_altair: option_wrapper(|| {
+                u64::checked_pow(2, 24)?.checked_mul(3)
+            })
+            .expect("calculation does not overflow"),
+            min_slashing_penalty_quotient_altair: u64::checked_pow(2, 6)
+                .expect("pow does not overflow"),
+            proportional_slashing_multiplier_altair: 2,
+            inactivity_score_bias: 4,
+            inactivity_score_recovery_rate: 16,
+            min_sync_committee_participants: 1,
+            epochs_per_sync_committee_period: Epoch::new(512),
+            domain_sync_committee: 7,
+            domain_sync_committee_selection_proof: 8,
+            domain_contribution_and_proof: 9,
+            altair_fork_version: [0x01, 0x00, 0x00, 0x64],
+            altair_fork_epoch: Some(Epoch::new(256)),
+
+            /*
+             * Merge hard fork params
+             */
+            inactivity_penalty_quotient_bellatrix: u64::checked_pow(2, 24)
+                .expect("pow does not overflow"),
+            min_slashing_penalty_quotient_bellatrix: u64::checked_pow(2, 5)
+                .expect("pow does not overflow"),
+            proportional_slashing_multiplier_bellatrix: 3,
+            bellatrix_fork_version: [0x02, 0x00, 0x00, 0x64],
+            bellatrix_fork_epoch: None,
+            terminal_total_difficulty: Uint256::MAX
+                .checked_sub(Uint256::from(2u64.pow(10)))
+                .expect("subtraction does not overflow")
+                // Add 1 since the spec declares `2**256 - 2**10` and we use
+                // `Uint256::MAX` which is `2*256- 1`.
+                .checked_add(Uint256::one())
+                .expect("addition does not overflow"),
+            terminal_block_hash: Hash256::zero(),
+            terminal_block_hash_activation_epoch: Epoch::new(u64::MAX),
+
+            /*
+             * Network specific
+             */
+            boot_nodes: vec![],
+            network_id: 100, // Gnosis Chain network id
+            attestation_propagation_slot_range: 32,
+            attestation_subnet_count: 64,
+            random_subnets_per_validator: 1,
+            maximum_gossip_clock_disparity_millis: 500,
+            target_aggregators_per_committee: 16,
+            epochs_per_random_subnet_subscription: 256,
+        }
+    }
 }
 
 impl Default for ChainSpec {
@@ -746,6 +901,7 @@ impl Config {
         match self.preset_base.as_str() {
             "minimal" => Some(EthSpecId::Minimal),
             "mainnet" => Some(EthSpecId::Mainnet),
+            "gnosis" => Some(EthSpecId::Gnosis),
             _ => None,
         }
     }

consensus/types/src/eth_spec.rs

@@ -3,17 +3,17 @@ use crate::*;
 use safe_arith::SafeArith;
 use serde_derive::{Deserialize, Serialize};
 use ssz_types::typenum::{
-    Unsigned, U0, U1024, U1073741824, U1099511627776, U128, U16, U16777216, U2, U2048, U32, U4,
+    bit::B0, UInt, Unsigned, U0, U1024, U1048576, U1073741824, U1099511627776, U128, U16,
-    U4096, U512, U64, U65536, U8, U8192,
+    U16777216, U2, U2048, U256, U32, U4, U4096, U512, U625, U64, U65536, U8, U8192,
 };
 use std::fmt::{self, Debug};
 use std::str::FromStr;
 
-use ssz_types::typenum::{bit::B0, UInt, U1048576, U256, U625};
 pub type U5000 = UInt<UInt<UInt<U625, B0>, B0>, B0>; // 625 * 8 = 5000
 
 const MAINNET: &str = "mainnet";
 const MINIMAL: &str = "minimal";
+pub const GNOSIS: &str = "gnosis";
 
 /// Used to identify one of the `EthSpec` instances defined here.
 #[derive(Copy, Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -21,6 +21,7 @@ const MINIMAL: &str = "minimal";
 pub enum EthSpecId {
     Mainnet,
     Minimal,
+    Gnosis,
 }
 
 impl FromStr for EthSpecId {
@@ -30,6 +31,7 @@ impl FromStr for EthSpecId {
         match s {
             MAINNET => Ok(EthSpecId::Mainnet),
             MINIMAL => Ok(EthSpecId::Minimal),
+            GNOSIS => Ok(EthSpecId::Gnosis),
             _ => Err(format!("Unknown eth spec: {}", s)),
         }
     }
@@ -40,6 +42,7 @@ impl fmt::Display for EthSpecId {
         let s = match self {
             EthSpecId::Mainnet => MAINNET,
             EthSpecId::Minimal => MINIMAL,
+            EthSpecId::Gnosis => GNOSIS,
         };
         write!(f, "{}", s)
     }
@@ -317,3 +320,46 @@ impl EthSpec for MinimalEthSpec {
         EthSpecId::Minimal
     }
 }
+
+/// Gnosis Beacon Chain specifications.
+#[cfg_attr(feature = "arbitrary-fuzz", derive(arbitrary::Arbitrary))]
+#[derive(Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize)]
+pub struct GnosisEthSpec;
+
+impl EthSpec for GnosisEthSpec {
+    type JustificationBitsLength = U4;
+    type SubnetBitfieldLength = U64;
+    type MaxValidatorsPerCommittee = U2048;
+    type GenesisEpoch = U0;
+    type SlotsPerEpoch = U16;
+    type EpochsPerEth1VotingPeriod = U64;
+    type SlotsPerHistoricalRoot = U8192;
+    type EpochsPerHistoricalVector = U65536;
+    type EpochsPerSlashingsVector = U8192;
+    type HistoricalRootsLimit = U16777216;
+    type ValidatorRegistryLimit = U1099511627776;
+    type MaxProposerSlashings = U16;
+    type MaxAttesterSlashings = U2;
+    type MaxAttestations = U128;
+    type MaxDeposits = U16;
+    type MaxVoluntaryExits = U16;
+    type SyncCommitteeSize = U512;
+    type SyncCommitteeSubnetCount = U4;
+    type MaxBytesPerTransaction = U1073741824; // 1,073,741,824
+    type MaxTransactionsPerPayload = U1048576; // 1,048,576
+    type BytesPerLogsBloom = U256;
+    type GasLimitDenominator = U1024;
+    type MinGasLimit = U5000;
+    type MaxExtraDataBytes = U32;
+    type SyncSubcommitteeSize = U128; // 512 committee size / 4 sync committee subnet count
+    type MaxPendingAttestations = U2048; // 128 max attestations * 16 slots per epoch
+    type SlotsPerEth1VotingPeriod = U1024; // 64 epochs * 16 slots per epoch
+
+    fn default_spec() -> ChainSpec {
+        ChainSpec::gnosis()
+    }
+
+    fn spec_name() -> EthSpecId {
+        EthSpecId::Gnosis
+    }
+}

consensus/types/src/preset.rs

@@ -187,7 +187,7 @@ impl BellatrixPreset {
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::{MainnetEthSpec, MinimalEthSpec};
+    use crate::{GnosisEthSpec, MainnetEthSpec, MinimalEthSpec};
     use serde::de::DeserializeOwned;
     use std::env;
     use std::fs::File;
@@ -226,6 +226,11 @@ mod test {
         preset_test::<MainnetEthSpec>();
     }
 
+    #[test]
+    fn gnosis_presets_consistent() {
+        preset_test::<GnosisEthSpec>();
+    }
+
     #[test]
     fn minimal_presets_consistent() {
         preset_test::<MinimalEthSpec>();

lcli/src/main.rs

@@ -38,7 +38,7 @@ fn main() {
                 .value_name("STRING")
                 .takes_value(true)
                 .required(true)
-                .possible_values(&["minimal", "mainnet"])
+                .possible_values(&["minimal", "mainnet", "gnosis"])
                 .default_value("mainnet")
                 .global(true),
         )
@@ -665,6 +665,7 @@ fn main() {
         .and_then(|eth_spec_id| match eth_spec_id {
             EthSpecId::Minimal => run(EnvironmentBuilder::minimal(), &matches),
             EthSpecId::Mainnet => run(EnvironmentBuilder::mainnet(), &matches),
+            EthSpecId::Gnosis => run(EnvironmentBuilder::gnosis(), &matches),
         });
 
     match result {

lighthouse/Cargo.toml

@@ -16,6 +16,8 @@ modern = ["bls/supranational-force-adx"]
 milagro = ["bls/milagro"]
 # Support minimal spec (used for testing only).
 spec-minimal = []
+# Support Gnosis spec and Gnosis Beacon Chain.
+gnosis = []
 
 [dependencies]
 beacon_node = { "path" = "../beacon_node" }

lighthouse/environment/src/lib.rs

@@ -21,7 +21,7 @@ use std::path::PathBuf;
 use std::sync::Arc;
 use task_executor::{ShutdownReason, TaskExecutor};
 use tokio::runtime::{Builder as RuntimeBuilder, Runtime};
-use types::{EthSpec, MainnetEthSpec, MinimalEthSpec};
+use types::{EthSpec, GnosisEthSpec, MainnetEthSpec, MinimalEthSpec};
 
 #[cfg(target_family = "unix")]
 use {
@@ -87,6 +87,19 @@ impl EnvironmentBuilder<MainnetEthSpec> {
     }
 }
 
+impl EnvironmentBuilder<GnosisEthSpec> {
+    /// Creates a new builder using the `gnosis` eth2 specification.
+    pub fn gnosis() -> Self {
+        Self {
+            runtime: None,
+            log: None,
+            eth_spec_instance: GnosisEthSpec,
+            eth2_config: Eth2Config::gnosis(),
+            eth2_network_config: None,
+        }
+    }
+}
+
 impl<E: EthSpec> EnvironmentBuilder<E> {
     /// Specifies that a multi-threaded tokio runtime should be used. Ideal for production uses.
     ///

lighthouse/src/main.rs

@@ -52,11 +52,12 @@ fn main() {
                 "{}\n\
                  BLS library: {}\n\
                  SHA256 hardware acceleration: {}\n\
-                 Specs: mainnet (true), minimal ({})",
+                 Specs: mainnet (true), minimal ({}), gnosis ({})",
                  VERSION.replace("Lighthouse/", ""),
                  bls_library_name(),
                  have_sha_extensions(),
                  cfg!(feature = "spec-minimal"),
+                 cfg!(feature = "gnosis"),
             ).as_str()
         )
         .arg(
@@ -302,9 +303,11 @@ fn main() {
 
         match eth_spec_id {
             EthSpecId::Mainnet => run(EnvironmentBuilder::mainnet(), &matches, eth2_network_config),
+            #[cfg(feature = "gnosis")]
+            EthSpecId::Gnosis => run(EnvironmentBuilder::gnosis(), &matches, eth2_network_config),
             #[cfg(feature = "spec-minimal")]
             EthSpecId::Minimal => run(EnvironmentBuilder::minimal(), &matches, eth2_network_config),
-            #[cfg(not(feature = "spec-minimal"))]
+            #[cfg(not(all(feature = "spec-minimal", feature = "gnosis")))]
             other => {
                 eprintln!(
                     "Eth spec `{}` is not supported by this build of Lighthouse",