1030 lines
38 KiB
Nim
1030 lines
38 KiB
Nim
import
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bitops, chronicles, options, tables,
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ssz, beacon_chain_db, state_transition, extras,
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beacon_node_types, metrics,
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spec/[crypto, datatypes, digest, helpers, validator]
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declareCounter beacon_reorgs_total, "Total occurrences of reorganizations of the chain" # On fork choice
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logScope: topics = "blkpool"
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proc updateStateData*(
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pool: BlockPool, state: var StateData, bs: BlockSlot) {.gcsafe.}
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proc add*(
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pool: var BlockPool, blockRoot: Eth2Digest,
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signedBlock: SignedBeaconBlock): BlockRef {.gcsafe.}
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template withState*(
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pool: BlockPool, cache: var StateData, blockSlot: BlockSlot, body: untyped): untyped =
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## Helper template that updates state to a particular BlockSlot - usage of
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## cache is unsafe outside of block.
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## TODO async transformations will lead to a race where cache gets updated
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## while waiting for future to complete - catch this here somehow?
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updateStateData(pool, cache, blockSlot)
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template hashedState(): HashedBeaconState {.inject, used.} = cache.data
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template state(): BeaconState {.inject, used.} = cache.data.data
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template blck(): BlockRef {.inject, used.} = cache.blck
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template root(): Eth2Digest {.inject, used.} = cache.data.root
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body
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func parent*(bs: BlockSlot): BlockSlot =
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## Return a blockslot representing the previous slot, using the parent block
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## if the current slot had a block
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if bs.slot == Slot(0):
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BlockSlot(blck: nil, slot: Slot(0))
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else:
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BlockSlot(
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blck: if bs.slot > bs.blck.slot: bs.blck else: bs.blck.parent,
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slot: bs.slot - 1
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)
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func link(parent, child: BlockRef) =
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doAssert (not (parent.root == Eth2Digest() or child.root == Eth2Digest())),
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"blocks missing root!"
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doAssert parent.root != child.root, "self-references not allowed"
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child.parent = parent
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parent.children.add(child)
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func isAncestorOf*(a, b: BlockRef): bool =
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var b = b
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var depth = 0
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const maxDepth = (100'i64 * 365 * 24 * 60 * 60 div SECONDS_PER_SLOT.int)
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while true:
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if a == b: return true
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# for now, use an assert for block chain length since a chain this long
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# indicates a circular reference here..
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doAssert depth < maxDepth
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depth += 1
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if a.slot >= b.slot or b.parent.isNil:
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return false
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doAssert b.slot > b.parent.slot
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b = b.parent
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func getAncestorAt*(blck: BlockRef, slot: Slot): BlockRef =
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## Return the most recent block as of the time at `slot` that not more recent
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## than `blck` itself
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var blck = blck
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var depth = 0
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const maxDepth = (100'i64 * 365 * 24 * 60 * 60 div SECONDS_PER_SLOT.int)
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while true:
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if blck.slot <= slot:
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return blck
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if blck.parent.isNil:
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return nil
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doAssert depth < maxDepth
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depth += 1
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blck = blck.parent
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func get_ancestor*(blck: BlockRef, slot: Slot): BlockRef =
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## https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/fork-choice.md#get_ancestor
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## Return ancestor at slot, or nil if queried block is older
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var blck = blck
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var depth = 0
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const maxDepth = (100'i64 * 365 * 24 * 60 * 60 div SECONDS_PER_SLOT.int)
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while true:
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if blck.slot == slot:
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return blck
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if blck.slot < slot:
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return nil
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if blck.parent.isNil:
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return nil
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doAssert depth < maxDepth
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depth += 1
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blck = blck.parent
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func atSlot*(blck: BlockRef, slot: Slot): BlockSlot =
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## Return a BlockSlot at a given slot, with the block set to the closest block
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## available. If slot comes from before the block, a suitable block ancestor
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## will be used, else blck is returned as if all slots after it were empty.
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## This helper is useful when imagining what the chain looked like at a
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## particular moment in time, or when imagining what it will look like in the
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## near future if nothing happens (such as when looking ahead for the next
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## block proposal)
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BlockSlot(blck: blck.getAncestorAt(slot), slot: slot)
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func init*(T: type BlockRef, root: Eth2Digest, slot: Slot): BlockRef =
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BlockRef(
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root: root,
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slot: slot
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)
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func init*(T: type BlockRef, root: Eth2Digest, blck: BeaconBlock): BlockRef =
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BlockRef.init(root, blck.slot)
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func findAncestorBySlot*(blck: BlockRef, slot: Slot): BlockSlot =
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## Find the first ancestor that has a slot number less than or equal to `slot`
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doAssert(not blck.isNil)
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var ret = blck
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while ret.parent != nil and ret.slot > slot:
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ret = ret.parent
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BlockSlot(blck: ret, slot: slot)
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proc init*(T: type BlockPool, db: BeaconChainDB): BlockPool =
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# TODO we require that the db contains both a head and a tail block -
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# asserting here doesn't seem like the right way to go about it however..
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let
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tailBlockRoot = db.getTailBlock()
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headBlockRoot = db.getHeadBlock()
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doAssert tailBlockRoot.isSome(), "Missing tail block, database corrupt?"
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doAssert headBlockRoot.isSome(), "Missing head block, database corrupt?"
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let
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tailRoot = tailBlockRoot.get()
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tailBlock = db.getBlock(tailRoot).get()
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tailRef = BlockRef.init(tailRoot, tailBlock.message)
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headRoot = headBlockRoot.get()
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var
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blocks = {tailRef.root: tailRef}.toTable()
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latestStateRoot = Option[tuple[stateRoot: Eth2Digest, blckRef: BlockRef]]()
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headRef: BlockRef
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if headRoot != tailRoot:
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var curRef: BlockRef
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for root, blck in db.getAncestors(headRoot):
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if root == tailRef.root:
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doAssert(not curRef.isNil)
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link(tailRef, curRef)
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curRef = curRef.parent
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break
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let newRef = BlockRef.init(root, blck.message)
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if curRef == nil:
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curRef = newRef
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headRef = newRef
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else:
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link(newRef, curRef)
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curRef = curRef.parent
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blocks[curRef.root] = curRef
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trace "Populating block pool", key = curRef.root, val = curRef
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if latestStateRoot.isNone() and db.containsState(blck.message.state_root):
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latestStateRoot = some((blck.message.state_root, curRef))
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doAssert curRef == tailRef,
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"head block does not lead to tail, database corrupt?"
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else:
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headRef = tailRef
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if latestStateRoot.isNone():
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doAssert db.containsState(tailBlock.message.state_root),
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"state data missing for tail block, database corrupt?"
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latestStateRoot = some((tailBlock.message.state_root, tailRef))
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# TODO can't do straight init because in mainnet config, there are too
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# many live beaconstates on the stack...
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var tmpState = new Option[BeaconState]
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# We're only saving epoch boundary states in the database right now, so when
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# we're loading the head block, the corresponding state does not necessarily
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# exist in the database - we'll load this latest state we know about and use
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# that as finalization point.
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tmpState[] = db.getState(latestStateRoot.get().stateRoot)
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let
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finalizedSlot =
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tmpState[].get().finalized_checkpoint.epoch.compute_start_slot_at_epoch()
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finalizedHead = headRef.findAncestorBySlot(finalizedSlot)
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justifiedSlot =
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tmpState[].get().current_justified_checkpoint.epoch.compute_start_slot_at_epoch()
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justifiedHead = headRef.findAncestorBySlot(justifiedSlot)
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head = Head(blck: headRef, justified: justifiedHead)
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justifiedBlock = db.getBlock(justifiedHead.blck.root).get()
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justifiedStateRoot = justifiedBlock.message.state_root
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doAssert justifiedHead.slot >= finalizedHead.slot,
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"justified head comes before finalized head - database corrupt?"
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debug "Block pool initialized",
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head = head.blck, finalizedHead, tail = tailRef,
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totalBlocks = blocks.len
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let res = BlockPool(
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pending: initTable[Eth2Digest, SignedBeaconBlock](),
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missing: initTable[Eth2Digest, MissingBlock](),
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blocks: blocks,
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tail: tailRef,
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head: head,
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finalizedHead: finalizedHead,
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db: db,
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heads: @[head],
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)
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res.headState = StateData(
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data: HashedBeaconState(
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data: tmpState[].get(), root: latestStateRoot.get().stateRoot),
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blck: latestStateRoot.get().blckRef)
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res.updateStateData(res.headState, BlockSlot(blck: head.blck, slot: head.blck.slot))
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res.tmpState = res.headState
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tmpState[] = db.getState(justifiedStateRoot)
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res.justifiedState = StateData(
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data: HashedBeaconState(data: tmpState[].get(), root: justifiedStateRoot),
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blck: justifiedHead.blck)
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res
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proc addResolvedBlock(
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pool: var BlockPool, state: BeaconState, blockRoot: Eth2Digest,
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signedBlock: SignedBeaconBlock, parent: BlockRef): BlockRef =
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logScope: pcs = "block_resolution"
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doAssert state.slot == signedBlock.message.slot, "state must match block"
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let blockRef = BlockRef.init(blockRoot, signedBlock.message)
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link(parent, blockRef)
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pool.blocks[blockRoot] = blockRef
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trace "Populating block pool", key = blockRoot, val = blockRef
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# Resolved blocks should be stored in database
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pool.db.putBlock(blockRoot, signedBlock)
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# This block *might* have caused a justification - make sure we stow away
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# that information:
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let justifiedSlot =
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state.current_justified_checkpoint.epoch.compute_start_slot_at_epoch()
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var foundHead: Option[Head]
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for head in pool.heads.mitems():
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if head.blck.isAncestorOf(blockRef):
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if head.justified.slot != justifiedSlot:
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head.justified = blockRef.findAncestorBySlot(justifiedSlot)
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head.blck = blockRef
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foundHead = some(head)
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break
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if foundHead.isNone():
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foundHead = some(Head(
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blck: blockRef,
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justified: blockRef.findAncestorBySlot(justifiedSlot)))
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pool.heads.add(foundHead.get())
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info "Block resolved",
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blck = shortLog(signedBlock.message),
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blockRoot = shortLog(blockRoot),
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justifiedRoot = shortLog(foundHead.get().justified.blck.root),
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justifiedSlot = shortLog(foundHead.get().justified.slot),
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heads = pool.heads.len(),
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cat = "filtering"
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# Now that we have the new block, we should see if any of the previously
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# unresolved blocks magically become resolved
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# TODO there are more efficient ways of doing this that don't risk
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# running out of stack etc
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# TODO This code is convoluted because when there are more than ~1.5k
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# blocks being synced, there's a stack overflow as `add` gets called
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# for the whole chain of blocks. Instead we use this ugly field in `pool`
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# which could be avoided by refactoring the code
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if not pool.inAdd:
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pool.inAdd = true
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defer: pool.inAdd = false
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var keepGoing = true
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while keepGoing:
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let retries = pool.pending
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for k, v in retries:
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discard pool.add(k, v)
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# Keep going for as long as the pending pool is shrinking
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# TODO inefficient! so what?
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keepGoing = pool.pending.len < retries.len
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blockRef
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proc add*(
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pool: var BlockPool, blockRoot: Eth2Digest,
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signedBlock: SignedBeaconBlock): BlockRef {.gcsafe.} =
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## return the block, if resolved...
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## the state parameter may be updated to include the given block, if
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## everything checks out
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# TODO reevaluate passing the state in like this
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let blck = signedBlock.message
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doAssert blockRoot == hash_tree_root(blck)
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logScope: pcs = "block_addition"
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# Already seen this block??
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if blockRoot in pool.blocks:
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debug "Block already exists",
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blck = shortLog(blck),
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blockRoot = shortLog(blockRoot),
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cat = "filtering"
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return pool.blocks[blockRoot]
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pool.missing.del(blockRoot)
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# If the block we get is older than what we finalized already, we drop it.
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# One way this can happen is that we start resolving a block and finalization
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# happens in the meantime - the block we requested will then be stale
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# by the time it gets here.
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if blck.slot <= pool.finalizedHead.slot:
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debug "Old block, dropping",
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blck = shortLog(blck),
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tailSlot = shortLog(pool.tail.slot),
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blockRoot = shortLog(blockRoot),
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cat = "filtering"
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return
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let parent = pool.blocks.getOrDefault(blck.parent_root)
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if parent != nil:
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if parent.slot >= blck.slot:
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# TODO Malicious block? inform peer pool?
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notice "Invalid block slot",
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blck = shortLog(blck),
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blockRoot = shortLog(blockRoot),
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parentRoot = shortLog(parent.root),
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parentSlot = shortLog(parent.slot)
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return
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# The block might have been in either of pending or missing - we don't want
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# any more work done on its behalf
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pool.pending.del(blockRoot)
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# The block is resolved, now it's time to validate it to ensure that the
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# blocks we add to the database are clean for the given state
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# TODO if the block is from the future, we should not be resolving it (yet),
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# but maybe we should use it as a hint that our clock is wrong?
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updateStateData(pool, pool.tmpState, BlockSlot(blck: parent, slot: blck.slot - 1))
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if not state_transition(pool.tmpState.data, signedBlock, {}):
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# TODO find a better way to log all this block data
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notice "Invalid block",
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blck = shortLog(blck),
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blockRoot = shortLog(blockRoot),
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cat = "filtering"
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return
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# Careful, tmpState.data has been updated but not blck - we need to create
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# the BlockRef first!
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pool.tmpState.blck = pool.addResolvedBlock(
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pool.tmpState.data.data, blockRoot, signedBlock, parent)
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return pool.tmpState.blck
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# TODO already checked hash though? main reason to keep this is because
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# the pending pool calls this function back later in a loop, so as long
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# as pool.add(...) requires a SignedBeaconBlock, easier to keep them in
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# pending too.
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pool.pending[blockRoot] = signedBlock
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# TODO possibly, it makes sense to check the database - that would allow sync
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# to simply fill up the database with random blocks the other clients
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# think are useful - but, it would also risk filling the database with
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# junk that's not part of the block graph
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if blck.parent_root in pool.missing or
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blck.parent_root in pool.pending:
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return
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# This is an unresolved block - put its parent on the missing list for now...
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# TODO if we receive spam blocks, one heurestic to implement might be to wait
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# for a couple of attestations to appear before fetching parents - this
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# would help prevent using up network resources for spam - this serves
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# two purposes: one is that attestations are likely to appear for the
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# block only if it's valid / not spam - the other is that malicious
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# validators that are not proposers can sign invalid blocks and send
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# them out without penalty - but signing invalid attestations carries
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# a risk of being slashed, making attestations a more valuable spam
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# filter.
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# TODO when we receive the block, we don't know how many others we're missing
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# from that branch, so right now, we'll just do a blind guess
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let parentSlot = blck.slot - 1
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pool.missing[blck.parent_root] = MissingBlock(
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slots:
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# The block is at least two slots ahead - try to grab whole history
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if parentSlot > pool.head.blck.slot:
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parentSlot - pool.head.blck.slot
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else:
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# It's a sibling block from a branch that we're missing - fetch one
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# epoch at a time
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max(1.uint64, SLOTS_PER_EPOCH.uint64 -
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(parentSlot.uint64 mod SLOTS_PER_EPOCH.uint64))
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)
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debug "Unresolved block (parent missing)",
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blck = shortLog(blck),
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blockRoot = shortLog(blockRoot),
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pending = pool.pending.len,
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missing = pool.missing.len,
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cat = "filtering"
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func getRef*(pool: BlockPool, root: Eth2Digest): BlockRef =
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## Retrieve a resolved block reference, if available
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pool.blocks.getOrDefault(root, nil)
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proc getBlockRange*(pool: BlockPool, headBlock: Eth2Digest,
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startSlot: Slot, skipStep: Natural,
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output: var openarray[BlockRef]): Natural =
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## This function populates an `output` buffer of blocks
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## with a range starting from `startSlot` and skipping
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## every `skipTest` number of blocks.
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##
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## Please note that the function may not necessarily
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## populate the entire buffer. The values will be written
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## in a way such that the last block is placed at the end
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## of the buffer while the first indices of the buffer
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## may remain unwritten.
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##
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## The result value of the function will be the index of
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## the first block in the resulting buffer. If no values
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## were written to the buffer, the result will be equal to
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## `buffer.len`. In other words, you can use the function
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## like this:
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##
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## var buffer: array[N, BlockRef]
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## let startPos = pool.getBlockRange(headBlock, startSlot, skipStep, buffer)
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## for i in startPos ..< buffer.len:
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## echo buffer[i].slot
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##
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result = output.len
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trace "getBlockRange entered", headBlock, startSlot, skipStep
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var b = pool.getRef(headBlock)
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if b == nil:
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trace "head block not found", headBlock
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return
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trace "head block found", headBlock = b
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if b.slot < startSlot:
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trace "head block is older than startSlot", headBlockSlot = b.slot, startSlot
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return
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template skip(n: int) =
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let targetSlot = b.slot - Slot(n)
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while b.slot > targetSlot:
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if b.parent == nil:
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trace "stopping at parentless block", slot = b.slot, root = b.root
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return
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trace "skipping block", nextBlock = b.parent
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b = b.parent
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# We must compute the last block that is eligible for inclusion
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# in the results. This will be a block with a slot number that's
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# aligned to the stride of the requested block range, so we first
|
|
# compute the steps needed to get to an aligned position:
|
|
var blocksToSkip = b.slot.int mod skipStep
|
|
let alignedHeadSlot = b.slot.int - blocksToSkip
|
|
|
|
# Then we see if this aligned position is within our wanted
|
|
# range. If it's outside it, we must skip more blocks:
|
|
let lastWantedSlot = startSlot.int + (output.len - 1) * skipStep
|
|
if alignedHeadSlot > lastWantedSlot:
|
|
blocksToSkip += (alignedHeadSlot - lastWantedSlot)
|
|
|
|
# Finally, we skip the computed number of blocks
|
|
trace "aligning head", blocksToSkip
|
|
skip blocksToSkip
|
|
|
|
# From here, we can just write out the requested block range:
|
|
while b != nil and b.slot >= startSlot and result > 0:
|
|
dec result
|
|
output[result] = b
|
|
trace "getBlockRange result", position = result, blockSlot = b.slot
|
|
skip skipStep
|
|
|
|
func getBlockBySlot*(pool: BlockPool, slot: Slot): BlockRef =
|
|
## Retrieves the first block in the current canonical chain
|
|
## with slot number less or equal to `slot`.
|
|
pool.head.blck.findAncestorBySlot(slot).blck
|
|
|
|
func getBlockByPreciseSlot*(pool: BlockPool, slot: Slot): BlockRef =
|
|
## Retrieves a block from the canonical chain with a slot
|
|
## number equal to `slot`.
|
|
let found = pool.getBlockBySlot(slot)
|
|
if found.slot != slot: found else: nil
|
|
|
|
proc get*(pool: BlockPool, blck: BlockRef): BlockData =
|
|
## Retrieve the associated block body of a block reference
|
|
doAssert (not blck.isNil), "Trying to get nil BlockRef"
|
|
|
|
let data = pool.db.getBlock(blck.root)
|
|
doAssert data.isSome, "BlockRef without backing data, database corrupt?"
|
|
|
|
BlockData(data: data.get(), refs: blck)
|
|
|
|
proc get*(pool: BlockPool, root: Eth2Digest): Option[BlockData] =
|
|
## Retrieve a resolved block reference and its associated body, if available
|
|
let refs = pool.getRef(root)
|
|
|
|
if not refs.isNil:
|
|
some(pool.get(refs))
|
|
else:
|
|
none(BlockData)
|
|
|
|
func getOrResolve*(pool: var BlockPool, root: Eth2Digest): BlockRef =
|
|
## Fetch a block ref, or nil if not found (will be added to list of
|
|
## blocks-to-resolve)
|
|
result = pool.getRef(root)
|
|
|
|
if result.isNil:
|
|
pool.missing[root] = MissingBlock(slots: 1)
|
|
|
|
func checkMissing*(pool: var BlockPool): seq[FetchRecord] =
|
|
## Return a list of blocks that we should try to resolve from other client -
|
|
## to be called periodically but not too often (once per slot?)
|
|
var done: seq[Eth2Digest]
|
|
|
|
for k, v in pool.missing.mpairs():
|
|
if v.tries > 8:
|
|
done.add(k)
|
|
else:
|
|
inc v.tries
|
|
|
|
for k in done:
|
|
# TODO Need to potentially remove from pool.pending - this is currently a
|
|
# memory leak here!
|
|
pool.missing.del(k)
|
|
|
|
# simple (simplistic?) exponential backoff for retries..
|
|
for k, v in pool.missing.pairs():
|
|
if v.tries.popcount() == 1:
|
|
result.add(FetchRecord(root: k, historySlots: v.slots))
|
|
|
|
proc skipAndUpdateState(
|
|
state: var HashedBeaconState, slot: Slot,
|
|
afterUpdate: proc (state: HashedBeaconState)) =
|
|
while state.data.slot < slot:
|
|
# Process slots one at a time in case afterUpdate needs to see empty states
|
|
process_slots(state, state.data.slot + 1)
|
|
afterUpdate(state)
|
|
|
|
proc skipAndUpdateState(
|
|
state: var HashedBeaconState, signedBlock: SignedBeaconBlock, flags: UpdateFlags,
|
|
afterUpdate: proc (state: HashedBeaconState)): bool =
|
|
|
|
skipAndUpdateState(state, signedBlock.message.slot - 1, afterUpdate)
|
|
|
|
let ok = state_transition(state, signedBlock, flags)
|
|
|
|
afterUpdate(state)
|
|
|
|
ok
|
|
|
|
proc maybePutState(pool: BlockPool, state: HashedBeaconState, blck: BlockRef) =
|
|
# TODO we save state at every epoch start but never remove them - we also
|
|
# potentially save multiple states per slot if reorgs happen, meaning
|
|
# we could easily see a state explosion
|
|
logScope: pcs = "save_state_at_epoch_start"
|
|
|
|
if state.data.slot mod SLOTS_PER_EPOCH == 0:
|
|
if not pool.db.containsState(state.root):
|
|
info "Storing state",
|
|
blockRoot = shortLog(blck.root),
|
|
blockSlot = shortLog(blck.slot),
|
|
stateSlot = shortLog(state.data.slot),
|
|
stateRoot = shortLog(state.root),
|
|
cat = "caching"
|
|
pool.db.putState(state.root, state.data)
|
|
# TODO this should be atomic with the above write..
|
|
pool.db.putStateRoot(blck.root, state.data.slot, state.root)
|
|
|
|
proc rewindState(pool: BlockPool, state: var StateData, bs: BlockSlot):
|
|
seq[BlockData] =
|
|
logScope: pcs = "replay_state"
|
|
|
|
var ancestors = @[pool.get(bs.blck)]
|
|
# Common case: the last block applied is the parent of the block to apply:
|
|
if not bs.blck.parent.isNil and state.blck.root == bs.blck.parent.root and
|
|
state.data.data.slot < bs.blck.slot:
|
|
return ancestors
|
|
|
|
# It appears that the parent root of the proposed new block is different from
|
|
# what we expected. We will have to rewind the state to a point along the
|
|
# chain of ancestors of the new block. We will do this by loading each
|
|
# successive parent block and checking if we can find the corresponding state
|
|
# in the database.
|
|
var
|
|
stateRoot = pool.db.getStateRoot(bs.blck.root, bs.slot)
|
|
curBs = bs
|
|
|
|
# TODO this can happen when state root is saved but state is gone - this would
|
|
# indicate a corrupt database, but since we're not atomically
|
|
# writing and deleting state+root mappings in a single transaction, it's
|
|
# likely to happen and we guard against it here.
|
|
if stateRoot.isSome() and not pool.db.containsState(stateRoot.get()):
|
|
stateRoot = none(type(stateRoot.get()))
|
|
|
|
while stateRoot.isNone():
|
|
let parBs = curBs.parent()
|
|
if parBs.blck.isNil:
|
|
break # Bug probably!
|
|
|
|
if parBs.blck != curBs.blck:
|
|
ancestors.add(pool.get(parBs.blck))
|
|
|
|
if (let tmp = pool.db.getStateRoot(parBs.blck.root, parBs.slot); tmp.isSome()):
|
|
if pool.db.containsState(tmp.get):
|
|
stateRoot = tmp
|
|
break
|
|
|
|
curBs = parBs
|
|
|
|
if stateRoot.isNone():
|
|
# TODO this should only happen if the database is corrupt - we walked the
|
|
# list of parent blocks and couldn't find a corresponding state in the
|
|
# database, which should never happen (at least we should have the
|
|
# tail state in there!)
|
|
error "Couldn't find ancestor state root!",
|
|
blockRoot = shortLog(bs.blck.root),
|
|
blockSlot = shortLog(bs.blck.slot),
|
|
slot = shortLog(bs.slot),
|
|
cat = "crash"
|
|
doAssert false, "Oh noes, we passed big bang!"
|
|
|
|
let
|
|
ancestor = ancestors.pop()
|
|
ancestorState = pool.db.getState(stateRoot.get())
|
|
|
|
if ancestorState.isNone():
|
|
# TODO this should only happen if the database is corrupt - we walked the
|
|
# list of parent blocks and couldn't find a corresponding state in the
|
|
# database, which should never happen (at least we should have the
|
|
# tail state in there!)
|
|
error "Couldn't find ancestor state or block parent missing!",
|
|
blockRoot = shortLog(bs.blck.root),
|
|
blockSlot = shortLog(bs.blck.slot),
|
|
slot = shortLog(bs.slot),
|
|
cat = "crash"
|
|
doAssert false, "Oh noes, we passed big bang!"
|
|
|
|
trace "Replaying state transitions",
|
|
stateSlot = shortLog(state.data.data.slot),
|
|
ancestorStateRoot = shortLog(ancestor.data.message.state_root),
|
|
ancestorStateSlot = shortLog(ancestorState.get().slot),
|
|
slot = shortLog(bs.slot),
|
|
blockRoot = shortLog(bs.blck.root),
|
|
ancestors = ancestors.len,
|
|
cat = "replay_state"
|
|
|
|
state.data.data = ancestorState.get()
|
|
state.data.root = stateRoot.get()
|
|
state.blck = ancestor.refs
|
|
|
|
ancestors
|
|
|
|
proc updateStateData*(pool: BlockPool, state: var StateData, bs: BlockSlot) =
|
|
## Rewind or advance state such that it matches the given block and slot -
|
|
## this may include replaying from an earlier snapshot if blck is on a
|
|
## different branch or has advanced to a higher slot number than slot
|
|
## If slot is higher than blck.slot, replay will fill in with empty/non-block
|
|
## slots, else it is ignored
|
|
|
|
# We need to check the slot because the state might have moved forwards
|
|
# without blocks
|
|
if state.blck.root == bs.blck.root and state.data.data.slot <= bs.slot:
|
|
if state.data.data.slot != bs.slot:
|
|
# Might be that we're moving to the same block but later slot
|
|
skipAndUpdateState(state.data, bs.slot) do(state: HashedBeaconState):
|
|
pool.maybePutState(state, bs.blck)
|
|
|
|
return # State already at the right spot
|
|
|
|
let ancestors = rewindState(pool, state, bs)
|
|
|
|
# If we come this far, we found the state root. The last block on the stack
|
|
# is the one that produced this particular state, so we can pop it
|
|
# TODO it might be possible to use the latest block hashes from the state to
|
|
# do this more efficiently.. whatever!
|
|
|
|
# Time to replay all the blocks between then and now. We skip one because
|
|
# it's the one that we found the state with, and it has already been
|
|
# applied
|
|
for i in countdown(ancestors.len - 1, 0):
|
|
let ok =
|
|
skipAndUpdateState(state.data,
|
|
ancestors[i].data,
|
|
{skipBlsValidation, skipMerkleValidation, skipStateRootValidation}) do (state: HashedBeaconState):
|
|
pool.maybePutState(state, ancestors[i].refs)
|
|
doAssert ok, "Blocks in database should never fail to apply.."
|
|
|
|
skipAndUpdateState(state.data, bs.slot) do(state: HashedBeaconState):
|
|
pool.maybePutState(state, bs.blck)
|
|
|
|
state.blck = bs.blck
|
|
|
|
proc loadTailState*(pool: BlockPool): StateData =
|
|
## Load the state associated with the current tail in the pool
|
|
let stateRoot = pool.db.getBlock(pool.tail.root).get().message.state_root
|
|
StateData(
|
|
data: HashedBeaconState(
|
|
data: pool.db.getState(stateRoot).get(),
|
|
root: stateRoot),
|
|
blck: pool.tail
|
|
)
|
|
|
|
proc delState(pool: BlockPool, bs: BlockSlot) =
|
|
# Delete state state and mapping for a particular block+slot
|
|
if (let root = pool.db.getStateRoot(bs.blck.root, bs.slot); root.isSome()):
|
|
pool.db.delState(root.get())
|
|
pool.db.delStateRoot(bs.blck.root, bs.slot)
|
|
|
|
proc updateHead*(pool: BlockPool, newHead: BlockRef) =
|
|
## Update what we consider to be the current head, as given by the fork
|
|
## choice.
|
|
## The choice of head affects the choice of finalization point - the order
|
|
## of operations naturally becomes important here - after updating the head,
|
|
## blocks that were once considered potential candidates for a tree will
|
|
## now fall from grace, or no longer be considered resolved.
|
|
doAssert newHead.parent != nil or newHead.slot == 0
|
|
logScope: pcs = "fork_choice"
|
|
|
|
if pool.head.blck == newHead:
|
|
info "No head block update",
|
|
headBlockRoot = shortLog(newHead.root),
|
|
headBlockSlot = shortLog(newHead.slot),
|
|
cat = "fork_choice"
|
|
|
|
return
|
|
|
|
let
|
|
lastHead = pool.head
|
|
pool.db.putHeadBlock(newHead.root)
|
|
|
|
# Start off by making sure we have the right state
|
|
updateStateData(
|
|
pool, pool.headState, BlockSlot(blck: newHead, slot: newHead.slot))
|
|
|
|
let
|
|
justifiedSlot = pool.headState.data.data
|
|
.current_justified_checkpoint
|
|
.epoch
|
|
.compute_start_slot_at_epoch()
|
|
justifiedBS = newHead.findAncestorBySlot(justifiedSlot)
|
|
|
|
pool.head = Head(blck: newHead, justified: justifiedBS)
|
|
updateStateData(pool, pool.justifiedState, justifiedBS)
|
|
|
|
# TODO isAncestorOf may be expensive - too expensive?
|
|
if not lastHead.blck.isAncestorOf(newHead):
|
|
info "Updated head block (new parent)",
|
|
lastHeadRoot = shortLog(lastHead.blck.root),
|
|
parentRoot = shortLog(newHead.parent.root),
|
|
stateRoot = shortLog(pool.headState.data.root),
|
|
headBlockRoot = shortLog(pool.headState.blck.root),
|
|
stateSlot = shortLog(pool.headState.data.data.slot),
|
|
justifiedEpoch = shortLog(pool.headState.data.data.current_justified_checkpoint.epoch),
|
|
finalizedEpoch = shortLog(pool.headState.data.data.finalized_checkpoint.epoch),
|
|
cat = "fork_choice"
|
|
|
|
# A reasonable criterion for "reorganizations of the chain"
|
|
beacon_reorgs_total.inc()
|
|
else:
|
|
info "Updated head block",
|
|
stateRoot = shortLog(pool.headState.data.root),
|
|
headBlockRoot = shortLog(pool.headState.blck.root),
|
|
stateSlot = shortLog(pool.headState.data.data.slot),
|
|
justifiedEpoch = shortLog(pool.headState.data.data.current_justified_checkpoint.epoch),
|
|
finalizedEpoch = shortLog(pool.headState.data.data.finalized_checkpoint.epoch),
|
|
cat = "fork_choice"
|
|
|
|
let
|
|
finalizedEpochStartSlot =
|
|
pool.headState.data.data.finalized_checkpoint.epoch.
|
|
compute_start_slot_at_epoch()
|
|
# TODO there might not be a block at the epoch boundary - what then?
|
|
finalizedHead = newHead.findAncestorBySlot(finalizedEpochStartSlot)
|
|
|
|
doAssert (not finalizedHead.blck.isNil),
|
|
"Block graph should always lead to a finalized block"
|
|
|
|
if finalizedHead != pool.finalizedHead:
|
|
block: # Remove states, walking slot by slot
|
|
discard
|
|
# TODO this is very aggressive - in theory all our operations start at
|
|
# the finalized block so all states before that can be wiped..
|
|
# TODO this is disabled for now because the logic for initializing the
|
|
# block pool and potentially a few other places depend on certain
|
|
# states (like the tail state) being present. It's also problematic
|
|
# because it is not clear what happens when tail and finalized states
|
|
# happen on an empty slot..
|
|
# var cur = finalizedHead
|
|
# while cur != pool.finalizedHead:
|
|
# cur = cur.parent
|
|
# pool.delState(cur)
|
|
|
|
block: # Clean up block refs, walking block by block
|
|
var cur = finalizedHead.blck
|
|
while cur != pool.finalizedHead.blck:
|
|
# Finalization means that we choose a single chain as the canonical one -
|
|
# it also means we're no longer interested in any branches from that chain
|
|
# up to the finalization point.
|
|
# The new finalized head should not be cleaned! We start at its parent and
|
|
# clean everything including the old finalized head.
|
|
cur = cur.parent
|
|
|
|
# TODO what about attestations? we need to drop those too, though they
|
|
# *should* be pretty harmless
|
|
if cur.parent != nil: # This happens for the genesis / tail block
|
|
for child in cur.parent.children:
|
|
if child != cur:
|
|
# TODO also remove states associated with the unviable forks!
|
|
# TODO the easiest thing to do here would probably be to use
|
|
# pool.heads to find unviable heads, then walk those chains
|
|
# and remove everything.. currently, if there's a child with
|
|
# children of its own, those children will not be pruned
|
|
# correctly from the database
|
|
pool.blocks.del(child.root)
|
|
pool.db.delBlock(child.root)
|
|
cur.parent.children = @[cur]
|
|
|
|
pool.finalizedHead = finalizedHead
|
|
|
|
let hlen = pool.heads.len
|
|
for i in 0..<hlen:
|
|
let n = hlen - i - 1
|
|
if not pool.finalizedHead.blck.isAncestorOf(pool.heads[n].blck):
|
|
# Any heads that are not derived from the newly finalized block are no
|
|
# longer viable candidates for future head selection
|
|
pool.heads.del(n)
|
|
|
|
info "Finalized block",
|
|
finalizedBlockRoot = shortLog(finalizedHead.blck.root),
|
|
finalizedBlockSlot = shortLog(finalizedHead.slot),
|
|
headBlockRoot = shortLog(newHead.root),
|
|
headBlockSlot = shortLog(newHead.slot),
|
|
heads = pool.heads.len,
|
|
cat = "fork_choice"
|
|
|
|
# TODO prune everything before weak subjectivity period
|
|
|
|
func latestJustifiedBlock*(pool: BlockPool): BlockSlot =
|
|
## Return the most recent block that is justified and at least as recent
|
|
## as the latest finalized block
|
|
|
|
doAssert pool.heads.len > 0,
|
|
"We should have at least the genesis block in heaads"
|
|
doAssert (not pool.head.blck.isNil()),
|
|
"Genesis block will be head, if nothing else"
|
|
|
|
# Prefer stability: use justified block from current head to break ties!
|
|
result = pool.head.justified
|
|
for head in pool.heads[1 ..< ^0]:
|
|
if head.justified.slot > result.slot:
|
|
result = head.justified
|
|
|
|
proc isInitialized*(T: type BlockPool, db: BeaconChainDB): bool =
|
|
let
|
|
headBlockRoot = db.getHeadBlock()
|
|
tailBlockRoot = db.getTailBlock()
|
|
|
|
if not (headBlockRoot.isSome() and tailBlockRoot.isSome()):
|
|
return false
|
|
|
|
let
|
|
headBlock = db.getBlock(headBlockRoot.get())
|
|
tailBlock = db.getBlock(tailBlockRoot.get())
|
|
|
|
if not (headBlock.isSome() and tailBlock.isSome()):
|
|
return false
|
|
|
|
if not db.containsState(tailBlock.get().message.state_root):
|
|
return false
|
|
|
|
return true
|
|
|
|
proc preInit*(
|
|
T: type BlockPool, db: BeaconChainDB, state: BeaconState,
|
|
signedBlock: SignedBeaconBlock) =
|
|
# write a genesis state, the way the BlockPool expects it to be stored in
|
|
# database
|
|
# TODO probably should just init a blockpool with the freshly written
|
|
# state - but there's more refactoring needed to make it nice - doing
|
|
# a minimal patch for now..
|
|
let
|
|
blockRoot = hash_tree_root(signedBlock.message)
|
|
|
|
doAssert signedBlock.message.state_root == hash_tree_root(state)
|
|
notice "New database from snapshot",
|
|
blockRoot = shortLog(blockRoot),
|
|
stateRoot = shortLog(signedBlock.message.state_root),
|
|
fork = state.fork,
|
|
validators = state.validators.len(),
|
|
cat = "initialization"
|
|
|
|
db.putState(state)
|
|
db.putBlock(signedBlock)
|
|
db.putTailBlock(blockRoot)
|
|
db.putHeadBlock(blockRoot)
|
|
db.putStateRoot(blockRoot, state.slot, signedBlock.message.state_root)
|
|
|
|
proc getProposer*(pool: BlockPool, head: BlockRef, slot: Slot): Option[ValidatorPubKey] =
|
|
pool.withState(pool.tmpState, head.atSlot(slot)):
|
|
var cache = get_empty_per_epoch_cache()
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/validator.md#validator-assignments
|
|
let proposerIdx = get_beacon_proposer_index(state, cache)
|
|
if proposerIdx.isNone:
|
|
warn "Missing proposer index",
|
|
slot=slot,
|
|
epoch=slot.compute_epoch_at_slot,
|
|
num_validators=state.validators.len,
|
|
active_validators=
|
|
get_active_validator_indices(state, slot.compute_epoch_at_slot),
|
|
balances=state.balances
|
|
return
|
|
|
|
return some(state.validators[proposerIdx.get()].pubkey)
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/p2p-interface.md#global-topics
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proc isValidBeaconBlock*(pool: BlockPool,
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signed_beacon_block: SignedBeaconBlock, current_slot: Slot,
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flags: UpdateFlags): bool =
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# In general, checks are ordered from cheap to expensive. Especially, crypto
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# verification could be quite a bit more expensive than the rest. This is an
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# externally easy-to-invoke function by tossing network packets at the node.
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# The block is not from a future slot
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# TODO allow `MAXIMUM_GOSSIP_CLOCK_DISPARITY` leniency, especially towards
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# seemingly future slots.
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if not (signed_beacon_block.message.slot <= current_slot):
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debug "isValidBeaconBlock: block is from a future slot",
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signed_beacon_block_message_slot = signed_beacon_block.message.slot,
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current_slot = current_slot
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return false
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# The block is from a slot greater than the latest finalized slot (with a
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# MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance) -- i.e. validate that
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# signed_beacon_block.message.slot >
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# compute_start_slot_at_epoch(state.finalized_checkpoint.epoch)
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if not (signed_beacon_block.message.slot > pool.finalizedHead.slot):
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debug "isValidBeaconBlock: block is not from a slot greater than the latest finalized slot"
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return false
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# The block is the first block with valid signature received for the proposer
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# for the slot, signed_beacon_block.message.slot.
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# TODO might check unresolved/orphaned blocks too, and this might not see all
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# blocks at a given slot (though, in theory, those get checked elsewhere).
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let slotBlockRef =
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getBlockByPreciseSlot(pool, signed_beacon_block.message.slot)
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if (not slotBlockRef.isNil) and
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pool.get(slotBlockRef).data.message.proposer_index ==
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signed_beacon_block.message.proposer_index:
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debug "isValidBeaconBlock: block isn't first block with valid signature received for the proposer",
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signed_beacon_block_message_slot = signed_beacon_block.message.slot,
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blckRef = getBlockByPreciseSlot(pool, signed_beacon_block.message.slot)
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return false
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# The proposer signature, signed_beacon_block.signature, is valid with
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# respect to the proposer_index pubkey.
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# If this block doesn't have a parent we know about, we can't/don't really
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# trace it back to a known-good state/checkpoint to verify its prevenance;
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# while one could getOrResolve to queue up searching for missing parent it
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# might not be the best place. As much as feasible, this function aims for
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# answering yes/no, not queuing other action or otherwise altering state.
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let parent_ref = pool.getRef(signed_beacon_block.message.parent_root)
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if parent_ref.isNil:
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return false
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let bs =
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BlockSlot(blck: parent_ref, slot: pool.get(parent_ref).data.message.slot)
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pool.withState(pool.tmpState, bs):
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let
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blockRoot = hash_tree_root(signed_beacon_block.message)
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domain = get_domain(pool.headState.data.data, DOMAIN_BEACON_PROPOSER,
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compute_epoch_at_slot(signed_beacon_block.message.slot))
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signing_root = compute_signing_root(blockRoot, domain)
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proposer_index = signed_beacon_block.message.proposer_index
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if proposer_index >= pool.headState.data.data.validators.len.uint64:
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return false
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if not blsVerify(pool.headState.data.data.validators[proposer_index].pubkey,
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signing_root.data, signed_beacon_block.signature):
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debug "isValidBeaconBlock: block failed signature verification"
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return false
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true
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