mirror of
https://github.com/cwinfo/yggdrasil-go.git
synced 2024-11-15 15:30:29 +00:00
421 lines
12 KiB
Go
421 lines
12 KiB
Go
package yggdrasil
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// Wire formatting tools
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// These are all ugly and probably not very secure
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// TODO clean up unused/commented code, and add better comments to whatever is left
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// Packet types, as wire_encode_uint64(type) at the start of each packet
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const (
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wire_Traffic = iota // data being routed somewhere, handle for crypto
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wire_ProtocolTraffic // protocol traffic, pub keys for crypto
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wire_LinkProtocolTraffic // link proto traffic, pub keys for crypto
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wire_SwitchMsg // inside link protocol traffic header
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wire_SessionPing // inside protocol traffic header
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wire_SessionPong // inside protocol traffic header
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wire_DHTLookupRequest // inside protocol traffic header
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wire_DHTLookupResponse // inside protocol traffic header
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)
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// Calls wire_put_uint64 on a nil slice.
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func wire_encode_uint64(elem uint64) []byte {
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return wire_put_uint64(elem, nil)
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}
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// Encode uint64 using a variable length scheme.
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// Similar to binary.Uvarint, but big-endian.
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func wire_put_uint64(e uint64, out []byte) []byte {
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var b [10]byte
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i := len(b) - 1
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b[i] = byte(e & 0x7f)
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for e >>= 7; e != 0; e >>= 7 {
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i--
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b[i] = byte(e | 0x80)
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}
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return append(out, b[i:]...)
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}
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// Returns the length of a wire encoded uint64 of this value.
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func wire_uint64_len(elem uint64) int {
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l := 1
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for e := elem >> 7; e > 0; e >>= 7 {
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l++
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}
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return l
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}
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// Decode uint64 from a []byte slice.
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// Returns the decoded uint64 and the number of bytes used.
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func wire_decode_uint64(bs []byte) (uint64, int) {
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length := 0
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elem := uint64(0)
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for _, b := range bs {
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elem <<= 7
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elem |= uint64(b & 0x7f)
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length++
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if b&0x80 == 0 {
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break
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}
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}
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return elem, length
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}
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// Converts an int64 into uint64 so it can be written to the wire.
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// Non-negative integers are mapped to even integers: 0 -> 0, 1 -> 2, etc.
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// Negative integres are mapped to odd integes: -1 -> 1, -2 -> 3, etc.
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// This means the least significant bit is a sign bit.
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func wire_intToUint(i int64) uint64 {
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return ((uint64(-(i+1))<<1)|0x01)*(uint64(i)>>63) + (uint64(i)<<1)*(^uint64(i)>>63)
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}
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// Converts uint64 back to int64, genreally when being read from the wire.
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func wire_intFromUint(u uint64) int64 {
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return int64(u&0x01)*(-int64(u>>1)-1) + int64(^u&0x01)*int64(u>>1)
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}
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////////////////////////////////////////////////////////////////////////////////
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// Takes coords, returns coords prefixed with encoded coord length.
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func wire_encode_coords(coords []byte) []byte {
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coordLen := wire_encode_uint64(uint64(len(coords)))
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bs := make([]byte, 0, len(coordLen)+len(coords))
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bs = append(bs, coordLen...)
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bs = append(bs, coords...)
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return bs
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}
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// Puts a length prefix and the coords into bs, returns the wire formatted coords.
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// 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.
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func wire_put_coords(coords []byte, bs []byte) []byte {
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bs = wire_put_uint64(uint64(len(coords)), bs)
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bs = append(bs, coords...)
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return bs
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}
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// Takes a slice that begins with coords (starting with coord length).
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// Returns a slice of coords and the number of bytes read.
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// Used as part of various decode() functions for structs.
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func wire_decode_coords(packet []byte) ([]byte, int) {
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coordLen, coordBegin := wire_decode_uint64(packet)
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coordEnd := coordBegin + int(coordLen)
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if coordBegin == 0 || coordEnd > len(packet) {
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return nil, 0
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}
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return packet[coordBegin:coordEnd], coordEnd
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}
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////////////////////////////////////////////////////////////////////////////////
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// Encodes a swtichMsg into its wire format.
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func (m *switchMsg) encode() []byte {
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bs := wire_encode_uint64(wire_SwitchMsg)
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bs = append(bs, m.Root[:]...)
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bs = append(bs, wire_encode_uint64(wire_intToUint(m.TStamp))...)
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for _, hop := range m.Hops {
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bs = append(bs, wire_encode_uint64(uint64(hop.Port))...)
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bs = append(bs, hop.Next[:]...)
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bs = append(bs, hop.Sig[:]...)
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}
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return bs
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}
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// Decodes a wire formatted switchMsg into the struct, returns true if successful.
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func (m *switchMsg) decode(bs []byte) bool {
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var pType uint64
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var tstamp uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_SwitchMsg:
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return false
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case !wire_chop_slice(m.Root[:], &bs):
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return false
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case !wire_chop_uint64(&tstamp, &bs):
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return false
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}
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m.TStamp = wire_intFromUint(tstamp)
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for len(bs) > 0 {
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var hop switchMsgHop
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switch {
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case !wire_chop_uint64((*uint64)(&hop.Port), &bs):
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return false
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case !wire_chop_slice(hop.Next[:], &bs):
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return false
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case !wire_chop_slice(hop.Sig[:], &bs):
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return false
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}
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m.Hops = append(m.Hops, hop)
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}
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return true
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}
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////////////////////////////////////////////////////////////////////////////////
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// A utility function used to copy bytes into a slice and advance the beginning of the source slice, returns true if successful.
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func wire_chop_slice(toSlice []byte, fromSlice *[]byte) bool {
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if len(*fromSlice) < len(toSlice) {
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return false
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}
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copy(toSlice, *fromSlice)
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*fromSlice = (*fromSlice)[len(toSlice):]
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return true
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}
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// A utility function to extract coords from a slice and advance the source slices, returning true if successful.
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func wire_chop_coords(toCoords *[]byte, fromSlice *[]byte) bool {
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coords, coordLen := wire_decode_coords(*fromSlice)
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if coordLen == 0 {
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return false
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}
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*toCoords = append((*toCoords)[:0], coords...)
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*fromSlice = (*fromSlice)[coordLen:]
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return true
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}
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// 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.
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func wire_chop_uint64(toUInt64 *uint64, fromSlice *[]byte) bool {
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dec, decLen := wire_decode_uint64(*fromSlice)
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if decLen == 0 {
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return false
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}
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*toUInt64 = dec
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*fromSlice = (*fromSlice)[decLen:]
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return true
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}
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////////////////////////////////////////////////////////////////////////////////
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// Wire traffic packets
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// The wire format for ordinary IPv6 traffic encapsulated by the network.
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type wire_trafficPacket struct {
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Coords []byte
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Handle handle
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Nonce boxNonce
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Payload []byte
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}
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// Encodes a wire_trafficPacket into its wire format.
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func (p *wire_trafficPacket) encode() []byte {
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bs := util_getBytes()
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bs = wire_put_uint64(wire_Traffic, bs)
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bs = wire_put_coords(p.Coords, bs)
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bs = append(bs, p.Handle[:]...)
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bs = append(bs, p.Nonce[:]...)
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bs = append(bs, p.Payload...)
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return bs
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}
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// Decodes an encoded wire_trafficPacket into the struct, returning true if successful.
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func (p *wire_trafficPacket) decode(bs []byte) bool {
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var pType uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_Traffic:
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return false
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case !wire_chop_coords(&p.Coords, &bs):
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return false
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case !wire_chop_slice(p.Handle[:], &bs):
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return false
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case !wire_chop_slice(p.Nonce[:], &bs):
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return false
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}
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p.Payload = append(util_getBytes(), bs...)
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return true
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}
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// The wire format for protocol traffic, such as dht req/res or session ping/pong packets.
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type wire_protoTrafficPacket struct {
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Coords []byte
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ToKey boxPubKey
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FromKey boxPubKey
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Nonce boxNonce
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Payload []byte
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}
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// Encodes a wire_protoTrafficPacket into its wire format.
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func (p *wire_protoTrafficPacket) encode() []byte {
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coords := wire_encode_coords(p.Coords)
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bs := wire_encode_uint64(wire_ProtocolTraffic)
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bs = append(bs, coords...)
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bs = append(bs, p.ToKey[:]...)
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bs = append(bs, p.FromKey[:]...)
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bs = append(bs, p.Nonce[:]...)
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bs = append(bs, p.Payload...)
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return bs
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}
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// Decodes an encoded wire_protoTrafficPacket into the struct, returning true if successful.
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func (p *wire_protoTrafficPacket) decode(bs []byte) bool {
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var pType uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_ProtocolTraffic:
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return false
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case !wire_chop_coords(&p.Coords, &bs):
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return false
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case !wire_chop_slice(p.ToKey[:], &bs):
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return false
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case !wire_chop_slice(p.FromKey[:], &bs):
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return false
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case !wire_chop_slice(p.Nonce[:], &bs):
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return false
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}
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p.Payload = bs
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return true
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}
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// The wire format for link protocol traffic, namely switchMsg.
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// There's really two layers of this, with the outer layer using permanent keys, and the inner layer using ephemeral keys.
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// The keys themselves are exchanged as part of the connection setup, and then omitted from the packets.
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// The two layer logic is handled in peers.go, but it's kind of ugly.
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type wire_linkProtoTrafficPacket struct {
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Nonce boxNonce
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Payload []byte
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}
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// Encodes a wire_linkProtoTrafficPacket into its wire format.
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func (p *wire_linkProtoTrafficPacket) encode() []byte {
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bs := wire_encode_uint64(wire_LinkProtocolTraffic)
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bs = append(bs, p.Nonce[:]...)
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bs = append(bs, p.Payload...)
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return bs
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}
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// Decodes an encoded wire_linkProtoTrafficPacket into the struct, returning true if successful.
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func (p *wire_linkProtoTrafficPacket) decode(bs []byte) bool {
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var pType uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_LinkProtocolTraffic:
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return false
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case !wire_chop_slice(p.Nonce[:], &bs):
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return false
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}
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p.Payload = bs
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return true
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}
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////////////////////////////////////////////////////////////////////////////////
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// Encodes a sessionPing into its wire format.
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func (p *sessionPing) encode() []byte {
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var pTypeVal uint64
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if p.IsPong {
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pTypeVal = wire_SessionPong
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} else {
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pTypeVal = wire_SessionPing
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}
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bs := wire_encode_uint64(pTypeVal)
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//p.sendPermPub used in top level (crypto), so skipped here
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bs = append(bs, p.Handle[:]...)
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bs = append(bs, p.SendSesPub[:]...)
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bs = append(bs, wire_encode_uint64(wire_intToUint(p.Tstamp))...)
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coords := wire_encode_coords(p.Coords)
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bs = append(bs, coords...)
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bs = append(bs, wire_encode_uint64(uint64(p.MTU))...)
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return bs
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}
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// Decodes an encoded sessionPing into the struct, returning true if successful.
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func (p *sessionPing) decode(bs []byte) bool {
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var pType uint64
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var tstamp uint64
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var mtu uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_SessionPing && pType != wire_SessionPong:
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return false
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//p.sendPermPub used in top level (crypto), so skipped here
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case !wire_chop_slice(p.Handle[:], &bs):
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return false
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case !wire_chop_slice(p.SendSesPub[:], &bs):
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return false
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case !wire_chop_uint64(&tstamp, &bs):
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return false
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case !wire_chop_coords(&p.Coords, &bs):
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return false
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case !wire_chop_uint64(&mtu, &bs):
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mtu = 1280
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}
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p.Tstamp = wire_intFromUint(tstamp)
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if pType == wire_SessionPong {
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p.IsPong = true
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}
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p.MTU = uint16(mtu)
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return true
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}
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////////////////////////////////////////////////////////////////////////////////
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// Encodes a dhtReq into its wire format.
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func (r *dhtReq) encode() []byte {
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coords := wire_encode_coords(r.Coords)
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bs := wire_encode_uint64(wire_DHTLookupRequest)
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bs = append(bs, coords...)
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bs = append(bs, r.Dest[:]...)
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return bs
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}
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// Decodes an encoded dhtReq into the struct, returning true if successful.
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func (r *dhtReq) decode(bs []byte) bool {
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var pType uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_DHTLookupRequest:
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return false
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case !wire_chop_coords(&r.Coords, &bs):
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return false
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case !wire_chop_slice(r.Dest[:], &bs):
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return false
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default:
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return true
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}
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}
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// Encodes a dhtRes into its wire format.
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func (r *dhtRes) encode() []byte {
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coords := wire_encode_coords(r.Coords)
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bs := wire_encode_uint64(wire_DHTLookupResponse)
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bs = append(bs, coords...)
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bs = append(bs, r.Dest[:]...)
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for _, info := range r.Infos {
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coords = wire_encode_coords(info.coords)
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bs = append(bs, info.key[:]...)
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bs = append(bs, coords...)
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}
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return bs
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}
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// Decodes an encoded dhtRes into the struct, returning true if successful.
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func (r *dhtRes) decode(bs []byte) bool {
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var pType uint64
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switch {
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case !wire_chop_uint64(&pType, &bs):
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return false
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case pType != wire_DHTLookupResponse:
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return false
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case !wire_chop_coords(&r.Coords, &bs):
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return false
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case !wire_chop_slice(r.Dest[:], &bs):
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return false
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}
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for len(bs) > 0 {
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info := dhtInfo{}
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switch {
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case !wire_chop_slice(info.key[:], &bs):
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return false
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case !wire_chop_coords(&info.coords, &bs):
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return false
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}
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r.Infos = append(r.Infos, &info)
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}
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return true
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}
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