Routing gossip protocol for the Lightning Network, per BOLT #7.

Overview

This module provides types, encoding/decoding, and validation for BOLT #7 routing gossip messages. The protocol enables nodes to share channel and node information across the network.

Usage

Import this module to access all BOLT #7 functionality:

import Lightning.Protocol.BOLT7

Decoding messages

-- Decode a channel_announcement from wire format
case decodeChannelAnnouncement wireBytes of
  Left err -> handleError err
  Right (msg, rest) -> processAnnouncement msg

Encoding messages

-- Encode a gossip_timestamp_filter
let msg = GossipTimestampFilter
      { gossipFilterChainHash      = mainnetChainHash
      , gossipFilterFirstTimestamp = 1609459200
      , gossipFilterTimestampRange = 86400
      }
let wireBytes = encodeGossipTimestampFilter msg

Validation

-- Validate a channel_announcement before processing
case validateChannelAnnouncement announcement of
  Left ValidateNodeIdOrdering -> rejectMessage
  Right () -> processValidMessage

Signature verification

This library provides hash computation for signature verification:

-- Compute the hash that should be signed
let sigHash = channelAnnouncementHash encodedMessage
-- Verify signatures using ppad-secp256k1 (not included)

Protocol overview

BOLT #7 defines gossip messages for routing in the Lightning Network. Nodes use these messages to build a view of the channel graph.

Re-exported from Lightning.Protocol.BOLT7.Types.

Re-exported from Lightning.Protocol.BOLT7.Messages.

Re-exported from Lightning.Protocol.BOLT7.Codec.

Re-exported from Lightning.Protocol.BOLT7.Hash.

Re-exported from Lightning.Protocol.BOLT7.Validate.

BOLT #7 defines the following message types:

• 256: channel_announcement
• 257: node_announcement
• 258: channel_update
• 259: announcement_signatures
• 261: query_short_channel_ids
• 262: reply_short_channel_ids_end
• 263: query_channel_range
• 264: reply_channel_range
• 265: gossip_timestamp_filter

Channel announcement messages:

• channel_announcement (256) - public channel announcement
• announcement_signatures (259) - signatures enabling announcement

Node announcement message:

• node_announcement (257) - advertises node metadata

Channel update message:

• channel_update (258) - per-direction routing parameters

Gossip query messages:

• query_short_channel_ids (261) - request specific channel info
• reply_short_channel_ids_end (262) - concludes query response
• query_channel_range (263) - query channels in block range
• reply_channel_range (264) - response with channel IDs
• gossip_timestamp_filter (265) - constrain relayed gossip