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const cenc = require('compact-encoding')
const IPv4 = exports.IPv4 = {
preencode (state, ip) {
state.end += 4
},
encode (state, ip) {
const nums = ip.split('.')
state.buffer[state.start++] = Number(nums[0]) || 0
state.buffer[state.start++] = Number(nums[1]) || 0
state.buffer[state.start++] = Number(nums[2]) || 0
state.buffer[state.start++] = Number(nums[3]) || 0
},
decode (state) {
if (state.end - state.start < 4) throw new Error('Out of bounds')
return state.buffer[state.start++] + '.' + state.buffer[state.start++] + '.' + state.buffer[state.start++] + '.' + state.buffer[state.start++]
}
}
const peerIPv4 = {
preencode (state, peer) {
state.end += 6
},
encode (state, peer) {
IPv4.encode(state, peer.host)
cenc.uint16.encode(state, peer.port)
},
decode (state) {
return {
host: IPv4.decode(state),
port: cenc.uint16.decode(state)
}
}
}
const dhtPeerIPv4 = exports.dhtPeerIPv4 = {
preencode (state, peer) {
state.end += 6 + 32
},
encode (state, peer) {
cenc.fixed32.encode(state, peer.id)
IPv4.encode(state, peer.host)
cenc.uint16.encode(state, peer.port)
},
decode (state) {
return {
id: cenc.fixed32.decode(state),
host: IPv4.decode(state),
port: cenc.uint16.decode(state)
}
}
}
const dhtPeerIPv4Array = exports.dhtPeerIPv4Array = cenc.array(dhtPeerIPv4)
/* eslint-disable no-multi-spaces */
const TYPE = 0b0001
const HAS_TOKEN = 0b0010
const HAS_NODE_ID = 0b0100
const HAS_TARGET = 0b1001
const HAS_CLOSER_NODES = 0b1001
const RESPONSE = 0b0000
const REQUEST = 0b0001
const TOKEN = 0b0010
const NODE_ID = 0b0100
const TARGET = 0b1000 | REQUEST
const CLOSER_NODES = 0b1000 | RESPONSE
exports.message = {
preencode (state, m) {
state.end += 1 // version
state.end += 1 // flags
state.end += 2 // tid
state.end += 6 // to
if (m.token) state.end += 32
if (m.nodeId) state.end += 32
if (m.target) state.end += 32
if (m.closerNodes && m.closerNodes.length) dhtPeerIPv4Array.preencode(state, m.closerNodes)
if (m.command) cenc.string.preencode(state, m.command)
else cenc.uint.preencode(state, m.status)
cenc.buffer.preencode(state, m.value)
},
encode (state, m) {
const closerNodes = m.closerNodes || []
const flags = (m.token ? HAS_TOKEN : 0) |
(m.nodeId ? NODE_ID : 0) |
(m.target ? TARGET : 0) |
(closerNodes.length ? CLOSER_NODES : 0) |
(m.command ? REQUEST : 0)
state.buffer[state.start++] = 1
state.buffer[state.start++] = flags
cenc.uint16.encode(state, m.tid)
peerIPv4.encode(state, m.to)
if ((flags & HAS_TOKEN) === TOKEN) cenc.fixed32.encode(state, m.token)
if ((flags & HAS_NODE_ID) === NODE_ID) cenc.fixed32.encode(state, m.nodeId)
if ((flags & HAS_TARGET) === TARGET) cenc.fixed32.encode(state, m.target)
if ((flags & HAS_CLOSER_NODES) === CLOSER_NODES) dhtPeerIPv4Array.encode(state, closerNodes)
if ((flags & TYPE) === REQUEST) cenc.string.encode(state, m.command)
if ((flags & TYPE) === RESPONSE) cenc.uint.encode(state, m.status)
cenc.buffer.encode(state, m.value)
},
decode (state) {
const version = state.buffer[state.start++]
if (version !== 1) {
throw new Error('Incompatible version')
}
const flags = cenc.uint.decode(state)
return {
version: 1,
tid: cenc.uint16.decode(state),
from: null, // populated in caller
to: peerIPv4.decode(state),
token: ((flags & HAS_TOKEN) === TOKEN) ? cenc.fixed32.decode(state) : null,
nodeId: ((flags & HAS_NODE_ID) === NODE_ID) ? cenc.fixed32.decode(state) : null,
target: ((flags & HAS_TARGET) === TARGET) ? cenc.fixed32.decode(state) : null,
closerNodes: ((flags & HAS_CLOSER_NODES) === CLOSER_NODES) ? dhtPeerIPv4Array.decode(state) : null,
command: ((flags & TYPE) === REQUEST) ? cenc.string.decode(state) : null,
status: ((flags & TYPE) === RESPONSE) ? cenc.uint.decode(state) : 0,
value: cenc.buffer.decode(state)
}
}
}