pruning proof improvements

consensus/core/src/api/mod.rs

@@ -17,7 +17,7 @@ use crate::{
         tx::TxResult,
     },
     header::Header,
-    pruning::{PruningPointProof, PruningPointTrustedData, PruningPointsList},
+    pruning::{PruningPointProof, PruningPointTrustedData, PruningPointsList, PruningProofMetadata},
     trusted::{ExternalGhostdagData, TrustedBlock},
     tx::{MutableTransaction, Transaction, TransactionOutpoint, UtxoEntry},
     BlockHashSet, BlueWorkType, ChainPath,
@@ -203,7 +203,7 @@ pub trait ConsensusApi: Send + Sync {
         unimplemented!()
     }
 
-    fn validate_pruning_proof(&self, proof: &PruningPointProof) -> PruningImportResult<()> {
+    fn validate_pruning_proof(&self, proof: &PruningPointProof, proof_metadata: &PruningProofMetadata) -> PruningImportResult<()> {
         unimplemented!()
     }
 

consensus/core/src/errors/pruning.rs

@@ -59,6 +59,9 @@ pub enum PruningImportError {
 
     #[error("process exit was initiated while validating pruning point proof")]
     PruningValidationInterrupted,
+
+    #[error("block {0} at level {1} has invalid proof of work for level")]
+    ProofOfWorkFailed(Hash, BlockLevel),
 }
 
 pub type PruningImportResult<T> = std::result::Result<T, PruningImportError>;

consensus/core/src/lib.rs

@@ -41,6 +41,10 @@ pub mod utxo;
 /// overall blocks, so 2^192 is definitely a justified upper-bound.
 pub type BlueWorkType = spectre_math::Uint192;
 
+/// The extends directly from the expectation above about having no more than
+/// 2^128 work in a single block
+pub const MAX_WORK_LEVEL: BlockLevel = 128;
+
 /// The type used to represent the GHOSTDAG K parameter
 pub type KType = u16;
 

consensus/core/src/pruning.rs

@@ -1,6 +1,7 @@
 use crate::{
     header::Header,
     trusted::{TrustedGhostdagData, TrustedHeader},
+    BlueWorkType,
 };
 use spectre_hashes::Hash;
 use std::sync::Arc;
@@ -19,3 +20,15 @@ pub struct PruningPointTrustedData {
     /// Union of GHOSTDAG data required to verify blocks in the future of the pruning point
     pub ghostdag_blocks: Vec<TrustedGhostdagData>,
 }
+
+#[derive(Clone, Copy)]
+pub struct PruningProofMetadata {
+    /// The claimed work of the initial relay block (from the prover)
+    pub relay_block_blue_work: BlueWorkType,
+}
+
+impl PruningProofMetadata {
+    pub fn new(relay_block_blue_work: BlueWorkType) -> Self {
+        Self { relay_block_blue_work }
+    }
+}

consensus/pow/src/lib.rs

@@ -56,12 +56,22 @@ impl State {
 }
 
 pub fn calc_block_level(header: &Header, max_block_level: BlockLevel) -> BlockLevel {
+    let (block_level, _) = calc_block_level_check_pow(header, max_block_level);
+    block_level
+}
+
+pub fn calc_block_level_check_pow(header: &Header, max_block_level: BlockLevel) -> (BlockLevel, bool) {
     if header.parents_by_level.is_empty() {
-        return max_block_level; // Genesis has the max block level
+        return (max_block_level, true); // Genesis has the max block level
     }
 
     let state = State::new(header);
-    let (_, pow) = state.check_pow(header.nonce);
+    let (passed, pow) = state.check_pow(header.nonce);
+    let block_level = calc_level_from_pow(pow, max_block_level);
+    (block_level, passed)
+}
+
+pub fn calc_level_from_pow(pow: Uint256, max_block_level: BlockLevel) -> BlockLevel {
     let signed_block_level = max_block_level as i64 - pow.bits() as i64;
     max(signed_block_level, 0) as BlockLevel
 }

consensus/src/consensus/mod.rs

@@ -64,7 +64,7 @@ use spectre_consensus_core::{
     merkle::calc_hash_merkle_root,
     muhash::MuHashExtensions,
     network::NetworkType,
-    pruning::{PruningPointProof, PruningPointTrustedData, PruningPointsList},
+    pruning::{PruningPointProof, PruningPointTrustedData, PruningPointsList, PruningProofMetadata},
     trusted::{ExternalGhostdagData, TrustedBlock},
     tx::{MutableTransaction, Transaction, TransactionOutpoint, UtxoEntry},
     BlockHashSet, BlueWorkType, ChainPath, HashMapCustomHasher,
@@ -758,8 +758,12 @@ impl ConsensusApi for Consensus {
         calc_hash_merkle_root(txs.iter(), storage_mass_activated)
     }
 
-    fn validate_pruning_proof(&self, proof: &PruningPointProof) -> Result<(), PruningImportError> {
-        self.services.pruning_proof_manager.validate_pruning_point_proof(proof)
+    fn validate_pruning_proof(
+        &self,
+        proof: &PruningPointProof,
+        proof_metadata: &PruningProofMetadata,
+    ) -> Result<(), PruningImportError> {
+        self.services.pruning_proof_manager.validate_pruning_point_proof(proof, proof_metadata)
     }
 
     fn apply_pruning_proof(&self, proof: PruningPointProof, trusted_set: &[TrustedBlock]) -> PruningImportResult<()> {

consensus/src/consensus/services.rs

@@ -118,7 +118,6 @@ impl ConsensusServices {
             relations_services[0].clone(),
             storage.headers_store.clone(),
             reachability_service.clone(),
-            false,
         );
 
         let coinbase_manager = CoinbaseManager::new(

consensus/src/pipeline/header_processor/pre_ghostdag_validation.rs

@@ -9,7 +9,7 @@ use spectre_consensus_core::header::Header;
 use spectre_consensus_core::BlockLevel;
 use spectre_core::time::unix_now;
 use spectre_database::prelude::StoreResultExtensions;
-use std::cmp::max;
+use spectre_pow::calc_level_from_pow;
 
 impl HeaderProcessor {
     /// Validates the header in isolation including pow check against header declared bits.
@@ -102,8 +102,7 @@ impl HeaderProcessor {
         let state = spectre_pow::State::new(header);
         let (passed, pow) = state.check_pow(header.nonce);
         if passed || self.skip_proof_of_work {
-            let signed_block_level = self.max_block_level as i64 - pow.bits() as i64;
-            Ok(max(signed_block_level, 0) as BlockLevel)
+            Ok(calc_level_from_pow(pow, self.max_block_level))
         } else {
             Err(RuleError::InvalidPoW)
         }

consensus/src/processes/difficulty.rs

@@ -6,7 +6,7 @@ use crate::model::stores::{
 use spectre_consensus_core::{
     config::params::MIN_DIFFICULTY_WINDOW_LEN,
     errors::difficulty::{DifficultyError, DifficultyResult},
-    BlockHashSet, BlueWorkType,
+    BlockHashSet, BlueWorkType, MAX_WORK_LEVEL,
 };
 use spectre_math::{Uint256, Uint320};
 use std::{
@@ -282,6 +282,16 @@ pub fn calc_work(bits: u32) -> BlueWorkType {
     res.try_into().expect("Work should not exceed 2**192")
 }
 
+pub fn level_work(level: u8, max_block_level: u8) -> BlueWorkType {
+    // Need to make a special condition for level 0 to ensure true work is always used
+    if level == 0 {
+        return 0.into();
+    }
+    // We use 256 here so the result corresponds to the work at the level from calc_level_from_pow
+    let exp = (level as u32) + 256 - (max_block_level as u32);
+    BlueWorkType::from_u64(1) << exp.min(MAX_WORK_LEVEL as u32)
+}
+
 #[derive(Eq)]
 struct DifficultyBlock {
     timestamp: u64,
@@ -307,3 +317,55 @@ impl Ord for DifficultyBlock {
         self.timestamp.cmp(&other.timestamp).then_with(|| self.sortable_block.cmp(&other.sortable_block))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use spectre_consensus_core::{BlockLevel, BlueWorkType, MAX_WORK_LEVEL};
+    use spectre_math::{Uint256, Uint320};
+    use spectre_pow::calc_level_from_pow;
+
+    use crate::processes::difficulty::{calc_work, level_work};
+    use spectre_utils::hex::ToHex;
+
+    #[test]
+    fn test_target_levels() {
+        let max_block_level: BlockLevel = 225;
+        for level in 1..=max_block_level {
+            // required pow for level
+            let level_target = (Uint320::from_u64(1) << (max_block_level - level).max(MAX_WORK_LEVEL) as u32) - Uint320::from_u64(1);
+            let level_target = Uint256::from_be_bytes(level_target.to_be_bytes()[8..40].try_into().unwrap());
+            let calculated_level = calc_level_from_pow(level_target, max_block_level);
+
+            let true_level_work = calc_work(level_target.compact_target_bits());
+            let calc_level_work = level_work(level, max_block_level);
+
+            // A "good enough" estimate of level work is within 1% diff from work with actual level target
+            // It's hard to calculate percentages with these large numbers, so to get around using floats
+            // we multiply the difference by 100. if the result is <= the calc_level_work it means
+            // difference must have been less than 1%
+            let (percent_diff, overflowed) = (true_level_work - calc_level_work).overflowing_mul(BlueWorkType::from_u64(100));
+            let is_good_enough = percent_diff <= calc_level_work;
+
+            println!("Level {}:", level);
+            println!(
+                "    data | {} | {} | {} / {} |",
+                level_target.compact_target_bits(),
+                level_target.bits(),
+                calculated_level,
+                max_block_level
+            );
+            println!("    pow  | {}", level_target.to_hex());
+            println!("    work | 0000000000000000{}", true_level_work.to_hex());
+            println!("  lvwork | 0000000000000000{}", calc_level_work.to_hex());
+            println!(" diff<1% | {}", !overflowed && (is_good_enough));
+
+            assert!(is_good_enough);
+        }
+    }
+
+    #[test]
+    fn test_base_level_work() {
+        // Expect that at level 0, the level work is always 0
+        assert_eq!(BlueWorkType::from(0), level_work(0, 255));
+    }
+}

consensus/src/processes/ghostdag/protocol.rs

@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use spectre_consensus_core::{
     blockhash::{self, BlockHashExtensions, BlockHashes},
-    BlockHashMap, BlueWorkType, HashMapCustomHasher,
+    BlockHashMap, BlockLevel, BlueWorkType, HashMapCustomHasher,
 };
 use spectre_hashes::Hash;
 use spectre_utils::refs::Refs;
@@ -16,7 +16,7 @@ use crate::{
             relations::RelationsStoreReader,
         },
     },
-    processes::difficulty::calc_work,
+    processes::difficulty::{calc_work, level_work},
 };
 
 use super::ordering::*;
@@ -29,7 +29,15 @@ pub struct GhostdagManager<T: GhostdagStoreReader, S: RelationsStoreReader, U: R
     pub(super) relations_store: S,
     pub(super) headers_store: Arc<V>,
     pub(super) reachability_service: U,
-    use_score_as_work: bool,
+
+    /// Level work is a lower-bound for the amount of work represented by each block.
+    /// When running GD for higher-level sub-DAGs, this value should be set accordingly
+    /// to the work represented by that level, and then used as a lower bound
+    /// for the work calculated from header bits (which depends on current difficulty).
+    /// For instance, assuming level 80 (i.e., pow hash has at least 80 zeros) is always
+    /// above the difficulty target, all blocks in it should represent the same amount of
+    /// work regardless of whether current difficulty requires 20 zeros or 25 zeros.  
+    level_work: BlueWorkType,
 }
 
 impl<T: GhostdagStoreReader, S: RelationsStoreReader, U: ReachabilityService, V: HeaderStoreReader> GhostdagManager<T, S, U, V> {
@@ -40,9 +48,30 @@ impl<T: GhostdagStoreReader, S: RelationsStoreReader, U: ReachabilityService, V:
         relations_store: S,
         headers_store: Arc<V>,
         reachability_service: U,
-        use_score_as_work: bool,
     ) -> Self {
-        Self { genesis_hash, k, ghostdag_store, relations_store, reachability_service, headers_store, use_score_as_work }
+        // For ordinary GD, always keep level_work=0 so the lower bound is ineffective
+        Self { genesis_hash, k, ghostdag_store, relations_store, reachability_service, headers_store, level_work: 0.into() }
+    }
+
+    pub fn with_level(
+        genesis_hash: Hash,
+        k: KType,
+        ghostdag_store: Arc<T>,
+        relations_store: S,
+        headers_store: Arc<V>,
+        reachability_service: U,
+        level: BlockLevel,
+        max_block_level: BlockLevel,
+    ) -> Self {
+        Self {
+            genesis_hash,
+            k,
+            ghostdag_store,
+            relations_store,
+            reachability_service,
+            headers_store,
+            level_work: level_work(level, max_block_level),
+        }
     }
 
     pub fn genesis_ghostdag_data(&self) -> GhostdagData {
@@ -115,20 +144,21 @@ impl<T: GhostdagStoreReader, S: RelationsStoreReader, U: ReachabilityService, V:
             }
         }
 
+        // Handle the special case of origin children first
+        if selected_parent.is_origin() {
+            // ORIGIN is always a single parent so both blue score and work should remain zero
+            return new_block_data;
+        }
+
         let blue_score = self.ghostdag_store.get_blue_score(selected_parent).unwrap() + new_block_data.mergeset_blues.len() as u64;
 
-        let blue_work: BlueWorkType = if self.use_score_as_work {
-            blue_score.into()
-        } else {
-            let added_blue_work: BlueWorkType = new_block_data
-                .mergeset_blues
-                .iter()
-                .cloned()
-                .map(|hash| if hash.is_origin() { 0.into() } else { calc_work(self.headers_store.get_bits(hash).unwrap()) })
-                .sum();
-
-            self.ghostdag_store.get_blue_work(selected_parent).unwrap() + added_blue_work
-        };
+        let added_blue_work: BlueWorkType = new_block_data
+            .mergeset_blues
+            .iter()
+            .cloned()
+            .map(|hash| calc_work(self.headers_store.get_bits(hash).unwrap()).max(self.level_work))
+            .sum();
+        let blue_work: BlueWorkType = self.ghostdag_store.get_blue_work(selected_parent).unwrap() + added_blue_work;
 
         new_block_data.finalize_score_and_work(blue_score, blue_work);
 

consensus/src/processes/pruning_proof/apply.rs

@@ -5,6 +5,7 @@ use std::{
 };
 
 use itertools::Itertools;
+use rocksdb::WriteBatch;
 use spectre_consensus_core::{
     blockhash::{BlockHashes, ORIGIN},
     errors::pruning::{PruningImportError, PruningImportResult},
@@ -17,7 +18,6 @@ use spectre_core::{debug, trace};
 use spectre_hashes::Hash;
 use spectre_pow::calc_block_level;
 use spectre_utils::{binary_heap::BinaryHeapExtensions, vec::VecExtensions};
-use rocksdb::WriteBatch;
 
 use crate::{
     model::{
@@ -148,7 +148,7 @@ impl PruningProofManager {
         let mut up_heap = BinaryHeap::with_capacity(capacity_estimate);
         for header in proof.iter().flatten().cloned() {
             if let Vacant(e) = dag.entry(header.hash) {
-                // TODO: Check if pow passes
+                // pow passing has already been checked during validation
                 let block_level = calc_block_level(&header, self.max_block_level);
                 self.headers_store.insert(header.hash, header.clone(), block_level).unwrap();