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wire.go
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wire.go
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package yggdrasil
// Wire formatting tools
// These are all ugly and probably not very secure
// TODO clean up unused/commented code, and add better comments to whatever is left
// Packet types, as wire_encode_uint64(type) at the start of each packet
import (
"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
)
const (
wire_Traffic = iota // data being routed somewhere, handle for crypto
wire_ProtocolTraffic // protocol traffic, pub keys for crypto
wire_LinkProtocolTraffic // link proto traffic, pub keys for crypto
wire_SwitchMsg // inside link protocol traffic header
wire_SessionPing // inside protocol traffic header
wire_SessionPong // inside protocol traffic header
wire_DHTLookupRequest // inside protocol traffic header
wire_DHTLookupResponse // inside protocol traffic header
wire_NodeInfoRequest // inside protocol traffic header
wire_NodeInfoResponse // inside protocol traffic header
)
// Calls wire_put_uint64 on a nil slice.
func wire_encode_uint64(elem uint64) []byte {
return wire_put_uint64(elem, nil)
}
// Encode uint64 using a variable length scheme.
// Similar to binary.Uvarint, but big-endian.
func wire_put_uint64(e uint64, out []byte) []byte {
var b [10]byte
i := len(b) - 1
b[i] = byte(e & 0x7f)
for e >>= 7; e != 0; e >>= 7 {
i--
b[i] = byte(e | 0x80)
}
return append(out, b[i:]...)
}
// Returns the length of a wire encoded uint64 of this value.
func wire_uint64_len(elem uint64) int {
l := 1
for e := elem >> 7; e > 0; e >>= 7 {
l++
}
return l
}
// Decode uint64 from a []byte slice.
// Returns the decoded uint64 and the number of bytes used.
func wire_decode_uint64(bs []byte) (uint64, int) {
length := 0
elem := uint64(0)
for _, b := range bs {
elem <<= 7
elem |= uint64(b & 0x7f)
length++
if b&0x80 == 0 {
break
}
}
return elem, length
}
// Converts an int64 into uint64 so it can be written to the wire.
// Non-negative integers are mapped to even integers: 0 -> 0, 1 -> 2, etc.
// Negative integers are mapped to odd integers: -1 -> 1, -2 -> 3, etc.
// This means the least significant bit is a sign bit.
// This is known as zigzag encoding.
func wire_intToUint(i int64) uint64 {
// signed arithmetic shift
return uint64((i >> 63) ^ (i << 1))
}
// Converts uint64 back to int64, genreally when being read from the wire.
func wire_intFromUint(u uint64) int64 {
// non-arithmetic shift
return int64((u >> 1) ^ -(u & 1))
}
////////////////////////////////////////////////////////////////////////////////
// Takes coords, returns coords prefixed with encoded coord length.
func wire_encode_coords(coords []byte) []byte {
coordLen := wire_encode_uint64(uint64(len(coords)))
bs := make([]byte, 0, len(coordLen)+len(coords))
bs = append(bs, coordLen...)
bs = append(bs, coords...)
return bs
}
// Puts a length prefix and the coords into bs, returns the wire formatted coords.
// Useful in hot loops where we don't want to allocate and we know the rest of the later parts of the slice are safe to overwrite.
func wire_put_coords(coords []byte, bs []byte) []byte {
bs = wire_put_uint64(uint64(len(coords)), bs)
bs = append(bs, coords...)
return bs
}
// Takes a slice that begins with coords (starting with coord length).
// Returns a slice of coords and the number of bytes read.
// Used as part of various decode() functions for structs.
func wire_decode_coords(packet []byte) ([]byte, int) {
coordLen, coordBegin := wire_decode_uint64(packet)
coordEnd := coordBegin + int(coordLen)
if coordBegin == 0 || coordEnd > len(packet) {
return nil, 0
}
return packet[coordBegin:coordEnd], coordEnd
}
// Converts a []uint64 set of coords to a []byte set of coords.
func wire_coordsUint64stoBytes(in []uint64) (out []byte) {
for _, coord := range in {
c := wire_encode_uint64(coord)
out = append(out, c...)
}
return out
}
// Converts a []byte set of coords to a []uint64 set of coords.
func wire_coordsBytestoUint64s(in []byte) (out []uint64) {
offset := 0
for {
coord, length := wire_decode_uint64(in[offset:])
if length == 0 {
break
}
out = append(out, coord)
offset += length
}
return out
}
////////////////////////////////////////////////////////////////////////////////
// Encodes a swtichMsg into its wire format.
func (m *switchMsg) encode() []byte {
bs := wire_encode_uint64(wire_SwitchMsg)
bs = append(bs, m.Root[:]...)
bs = append(bs, wire_encode_uint64(wire_intToUint(m.TStamp))...)
for _, hop := range m.Hops {
bs = append(bs, wire_encode_uint64(uint64(hop.Port))...)
bs = append(bs, hop.Next[:]...)
bs = append(bs, hop.Sig[:]...)
}
return bs
}
// Decodes a wire formatted switchMsg into the struct, returns true if successful.
func (m *switchMsg) decode(bs []byte) bool {
var pType uint64
var tstamp uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_SwitchMsg:
return false
case !wire_chop_slice(m.Root[:], &bs):
return false
case !wire_chop_uint64(&tstamp, &bs):
return false
}
m.TStamp = wire_intFromUint(tstamp)
for len(bs) > 0 {
var hop switchMsgHop
switch {
case !wire_chop_uint64((*uint64)(&hop.Port), &bs):
return false
case !wire_chop_slice(hop.Next[:], &bs):
return false
case !wire_chop_slice(hop.Sig[:], &bs):
return false
}
m.Hops = append(m.Hops, hop)
}
return true
}
////////////////////////////////////////////////////////////////////////////////
// A utility function used to copy bytes into a slice and advance the beginning of the source slice, returns true if successful.
func wire_chop_slice(toSlice []byte, fromSlice *[]byte) bool {
if len(*fromSlice) < len(toSlice) {
return false
}
copy(toSlice, *fromSlice)
*fromSlice = (*fromSlice)[len(toSlice):]
return true
}
// A utility function to extract coords from a slice and advance the source slices, returning true if successful.
func wire_chop_coords(toCoords *[]byte, fromSlice *[]byte) bool {
coords, coordLen := wire_decode_coords(*fromSlice)
if coordLen == 0 {
return false
}
*toCoords = append((*toCoords)[:0], coords...)
*fromSlice = (*fromSlice)[coordLen:]
return true
}
// A utility function to extract a wire encoded uint64 into the provided pointer while advancing the start of the source slice, returning true if successful.
func wire_chop_uint64(toUInt64 *uint64, fromSlice *[]byte) bool {
dec, decLen := wire_decode_uint64(*fromSlice)
if decLen == 0 {
return false
}
*toUInt64 = dec
*fromSlice = (*fromSlice)[decLen:]
return true
}
////////////////////////////////////////////////////////////////////////////////
// Wire traffic packets
// The wire format for ordinary IPv6 traffic encapsulated by the network.
type wire_trafficPacket struct {
Coords []byte
Handle crypto.Handle
Nonce crypto.BoxNonce
Payload []byte
}
// Encodes a wire_trafficPacket into its wire format.
// The returned slice was taken from the pool.
func (p *wire_trafficPacket) encode() []byte {
bs := pool_getBytes(0)
bs = wire_put_uint64(wire_Traffic, bs)
bs = wire_put_coords(p.Coords, bs)
bs = append(bs, p.Handle[:]...)
bs = append(bs, p.Nonce[:]...)
bs = append(bs, p.Payload...)
return bs
}
// Decodes an encoded wire_trafficPacket into the struct, returning true if successful.
// Either way, the argument slice is added to the pool.
func (p *wire_trafficPacket) decode(bs []byte) bool {
defer pool_putBytes(bs)
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_Traffic:
return false
case !wire_chop_coords(&p.Coords, &bs):
return false
case !wire_chop_slice(p.Handle[:], &bs):
return false
case !wire_chop_slice(p.Nonce[:], &bs):
return false
}
p.Payload = append(p.Payload, bs...)
return true
}
// The wire format for protocol traffic, such as dht req/res or session ping/pong packets.
type wire_protoTrafficPacket struct {
Coords []byte
ToKey crypto.BoxPubKey
FromKey crypto.BoxPubKey
Nonce crypto.BoxNonce
Payload []byte
}
// Encodes a wire_protoTrafficPacket into its wire format.
func (p *wire_protoTrafficPacket) encode() []byte {
coords := wire_encode_coords(p.Coords)
bs := wire_encode_uint64(wire_ProtocolTraffic)
bs = append(bs, coords...)
bs = append(bs, p.ToKey[:]...)
bs = append(bs, p.FromKey[:]...)
bs = append(bs, p.Nonce[:]...)
bs = append(bs, p.Payload...)
return bs
}
// Decodes an encoded wire_protoTrafficPacket into the struct, returning true if successful.
func (p *wire_protoTrafficPacket) decode(bs []byte) bool {
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_ProtocolTraffic:
return false
case !wire_chop_coords(&p.Coords, &bs):
return false
case !wire_chop_slice(p.ToKey[:], &bs):
return false
case !wire_chop_slice(p.FromKey[:], &bs):
return false
case !wire_chop_slice(p.Nonce[:], &bs):
return false
}
p.Payload = bs
return true
}
// The wire format for link protocol traffic, namely switchMsg.
// There's really two layers of this, with the outer layer using permanent keys, and the inner layer using ephemeral keys.
// The keys themselves are exchanged as part of the connection setup, and then omitted from the packets.
// The two layer logic is handled in peers.go, but it's kind of ugly.
type wire_linkProtoTrafficPacket struct {
Nonce crypto.BoxNonce
Payload []byte
}
// Encodes a wire_linkProtoTrafficPacket into its wire format.
func (p *wire_linkProtoTrafficPacket) encode() []byte {
bs := wire_encode_uint64(wire_LinkProtocolTraffic)
bs = append(bs, p.Nonce[:]...)
bs = append(bs, p.Payload...)
return bs
}
// Decodes an encoded wire_linkProtoTrafficPacket into the struct, returning true if successful.
func (p *wire_linkProtoTrafficPacket) decode(bs []byte) bool {
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_LinkProtocolTraffic:
return false
case !wire_chop_slice(p.Nonce[:], &bs):
return false
}
p.Payload = bs
return true
}
////////////////////////////////////////////////////////////////////////////////
// Encodes a sessionPing into its wire format.
func (p *sessionPing) encode() []byte {
var pTypeVal uint64
if p.IsPong {
pTypeVal = wire_SessionPong
} else {
pTypeVal = wire_SessionPing
}
bs := wire_encode_uint64(pTypeVal)
//p.sendPermPub used in top level (crypto), so skipped here
bs = append(bs, p.Handle[:]...)
bs = append(bs, p.SendSesPub[:]...)
bs = append(bs, wire_encode_uint64(wire_intToUint(p.Tstamp))...)
coords := wire_encode_coords(p.Coords)
bs = append(bs, coords...)
bs = append(bs, wire_encode_uint64(uint64(p.MTU))...)
return bs
}
// Decodes an encoded sessionPing into the struct, returning true if successful.
func (p *sessionPing) decode(bs []byte) bool {
var pType uint64
var tstamp uint64
var mtu uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_SessionPing && pType != wire_SessionPong:
return false
//p.sendPermPub used in top level (crypto), so skipped here
case !wire_chop_slice(p.Handle[:], &bs):
return false
case !wire_chop_slice(p.SendSesPub[:], &bs):
return false
case !wire_chop_uint64(&tstamp, &bs):
return false
case !wire_chop_coords(&p.Coords, &bs):
return false
case !wire_chop_uint64(&mtu, &bs):
mtu = 1280
}
p.Tstamp = wire_intFromUint(tstamp)
if pType == wire_SessionPong {
p.IsPong = true
}
p.MTU = MTU(mtu)
return true
}
////////////////////////////////////////////////////////////////////////////////
// Encodes a nodeinfoReqRes into its wire format.
func (p *nodeinfoReqRes) encode() []byte {
var pTypeVal uint64
if p.IsResponse {
pTypeVal = wire_NodeInfoResponse
} else {
pTypeVal = wire_NodeInfoRequest
}
bs := wire_encode_uint64(pTypeVal)
bs = wire_put_coords(p.SendCoords, bs)
if pTypeVal == wire_NodeInfoResponse {
bs = append(bs, p.NodeInfo...)
}
return bs
}
// Decodes an encoded nodeinfoReqRes into the struct, returning true if successful.
func (p *nodeinfoReqRes) decode(bs []byte) bool {
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_NodeInfoRequest && pType != wire_NodeInfoResponse:
return false
case !wire_chop_coords(&p.SendCoords, &bs):
return false
}
if p.IsResponse = pType == wire_NodeInfoResponse; p.IsResponse {
if len(bs) == 0 {
return false
}
p.NodeInfo = make(NodeInfoPayload, len(bs))
if !wire_chop_slice(p.NodeInfo[:], &bs) {
return false
}
}
return true
}
////////////////////////////////////////////////////////////////////////////////
// Encodes a dhtReq into its wire format.
func (r *dhtReq) encode() []byte {
coords := wire_encode_coords(r.Coords)
bs := wire_encode_uint64(wire_DHTLookupRequest)
bs = append(bs, coords...)
bs = append(bs, r.Dest[:]...)
return bs
}
// Decodes an encoded dhtReq into the struct, returning true if successful.
func (r *dhtReq) decode(bs []byte) bool {
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_DHTLookupRequest:
return false
case !wire_chop_coords(&r.Coords, &bs):
return false
case !wire_chop_slice(r.Dest[:], &bs):
return false
default:
return true
}
}
// Encodes a dhtRes into its wire format.
func (r *dhtRes) encode() []byte {
coords := wire_encode_coords(r.Coords)
bs := wire_encode_uint64(wire_DHTLookupResponse)
bs = append(bs, coords...)
bs = append(bs, r.Dest[:]...)
for _, info := range r.Infos {
coords = wire_encode_coords(info.coords)
bs = append(bs, info.key[:]...)
bs = append(bs, coords...)
}
return bs
}
// Decodes an encoded dhtRes into the struct, returning true if successful.
func (r *dhtRes) decode(bs []byte) bool {
var pType uint64
switch {
case !wire_chop_uint64(&pType, &bs):
return false
case pType != wire_DHTLookupResponse:
return false
case !wire_chop_coords(&r.Coords, &bs):
return false
case !wire_chop_slice(r.Dest[:], &bs):
return false
}
for len(bs) > 0 {
info := dhtInfo{}
switch {
case !wire_chop_slice(info.key[:], &bs):
return false
case !wire_chop_coords(&info.coords, &bs):
return false
}
r.Infos = append(r.Infos, &info)
}
return true
}