Dissecting Bitcoin Core

Proposal: Review and update of the book "Dissection of Bitcoin"

Brief Contents

• Architecture
• Network Layer
  • ADDR Relay
  • Evicting An Incoming Connection
  • Evicting An Outgoing Connection
  • Socket Programming
  • Connection Manager
• Adresses
• Transactions
• Serialization
• Functional Test Framework

Contents in Detail

• Architecture
  • Executables
  • Protocol - P2P
  • Concurrency Model
    • TraceThread
    • Script Verification
    • Loading Blocks
    • Servicing RPC Calls
    • Load Peer Addresses From DNS Seeds
    • Send And Receive Messages To And From Peers
    • Initializing Network Connections
    • Opening Added Network Connections
    • Process Messages from net -> net_processing
  • Notifications Mechanism (ValidationInterface)
  • Regions
    • net.{h,cpp}
    • net_processing.{h,cpp}
    • validation.{h,cpp}
    • txmempool.{h,cpp}
    • coins.{h,cpp} & txdb.{h,cpp}
    • dbwrapper.{h,cpp} & indexes/
    • script/
    • consensus/
    • policy/
    • interface/
    • qt/
    • rpc/
    • wallet/
    • miner.{h,cpp}
  • Summary
  • References
• ADDR Relay
  • Connection Types
  • Peer seeding sources
    • 1. Loaded from peers.dat
    • 2. DNS Seeds
    • 3. Fixed seeds
    • 4. ADDR_FETCH via -seednode
    • 5. Manual connection in -connect mode
    • 6. Manual connection with -addnode
  • Initial Connection
  • ADDR or ADDRV2
  • RelayAddress()
  • MaybeSendAddr()
  • GETADDR
  • Summary
• Address Manager (AddrMan)
  • Original Implementation
  • Eclipse Attack
    • Deployed Countermeasures for Eclipse Attacks
      • Countermeasure 4: Feeler Connections
      • Countermeasure 3: test-before-evict
      • Countermeasure 1: Deterministic random eviction
      • Countermeasure 2: Random selection
      • Countermeasure 6: More buckets
      • Countermeasure 5: Anchor connections
    • Undeployed (or partially deployed) countermeasures
      • Countermeasure 7: More outgoing connections
      • Countermeasure 8: Ban unsolicited ADDR messages
      • Countermeasure 9: Diversify incoming connections
      • Countermeasure 10: Anomaly detection
  • Erebus Attack
    • Deployed Countermeasures for Erebus Attack
      • Countermeasure 2: More outgoing connections
      • Countermeasure 3: Selecting peers with AS topology information
    • Undeployed countermeasures
      • Countermeasure 1: Table size reduction
      • Countermeasure 4: Smarter eviction policy
  • Current Implementation
    • CNetAddr
    • CService
    • CAddress
    • CAddrInfo
    • CAddrMan
  • Adding New Address
  • Connecting to an Address
  • Test-Before-Evict
  • Responding to GETADDR Messages
  • Summary
  • References
• Evicting An Incoming Connection
  • Eviction Mechanism
    • Rule 1: Protect 4 peers with the highest network group
    • Rule 2: Protect 8 peers with the lowest minimum ping time
    • Rule 3: Protect 4 peers that most recently sent us novel transactions
    • Rule 4: Protect up to 8 block-relay only peers that have sent novel blocks
    • Rule 5: Protect 4 peers that most recently sent us novel blocks
    • Rule 6: Protect up to 1/4 peers connected via the onion service
    • Rule 7: Any remaining slots of the 1/4 peers connected, or at least 2 additional slots, are allocated to protect localhost peers
    • Rule 8: Protect the remaining peers until completing half of them all, prioritizing those with longest uptime
    • Rule 9: Consider only the peers preferred for eviction to be disconnected
    • Rule 10: Identify the network group with the most connections and evict the youngest member
  • Summary
  • References
• Evicting An Outgoing Connection
  • Disconnecting from bad outbound peers with bad headers chains in IBD
  • Disconnection of outbound peers on bad/slow chains
  • Connecting to a new outbound peer if the node's tip is stale
  • Summary
• Socket Programming
  • sockaddr_in
  • htonl() and htons()
  • socket()
  • setsockopt()
  • WSAStartup()
  • bind()
  • listen()
  • accept()
  • select()
  • poll()
  • recv()
  • send()
  • Summary
  • References
• Connection Manager
  • Starting The Node
  • Starting Connections
  • ThreadSocketHandler
  • ThreadDNSAddressSeed
  • ThreadOpenAddedConnections
  • ThreadOpenConnections
  • ThreadMessageHandler
  • Summary
• Adresses
• Transactions
• Serialization
  • Original Implementation
  • Relevant Changes
    • PR #352 - secure_allocator and zero_after_free_allocator
    • PR #1567 - CHashWriter
    • PR #2409 - CSerializeData
    • PR #4508 - CSizeComputer
    • PR #5510 - Big endian support
    • PR #6914 - prevector
  • Transactions Serialization - Current Implementation (BIP 144)
    • VarInt
    • SerializeTransaction()
    • UnserializeTransaction()
    • Serializing a transaction - Process
      • Sending Requested Transaction
• Functional Test Framework
  • test/test_framework/*
  • BitcoinTestFramework
  • TestNode
  • P2PInterface
  • Test 1 - Sending Money
  • Test 2 - Expected Mempool Behavior
  • Test 3 - Adding P2PInterface Connections
  • Summary
  • References