forked from quic-go/quic-go
/
handshake_message.go
137 lines (113 loc) · 3.18 KB
/
handshake_message.go
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package handshake
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"sort"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
"github.com/lucas-clemente/quic-go/qerr"
)
// A HandshakeMessage is a handshake message
type HandshakeMessage struct {
Tag Tag
Data map[Tag][]byte
}
var _ fmt.Stringer = &HandshakeMessage{}
// ParseHandshakeMessage reads a crypto message
func ParseHandshakeMessage(r io.Reader) (HandshakeMessage, error) {
slice4 := make([]byte, 4)
if _, err := io.ReadFull(r, slice4); err != nil {
return HandshakeMessage{}, err
}
messageTag := Tag(binary.LittleEndian.Uint32(slice4))
if _, err := io.ReadFull(r, slice4); err != nil {
return HandshakeMessage{}, err
}
nPairs := binary.LittleEndian.Uint32(slice4)
if nPairs > protocol.CryptoMaxParams {
return HandshakeMessage{}, qerr.CryptoTooManyEntries
}
index := make([]byte, nPairs*8)
if _, err := io.ReadFull(r, index); err != nil {
return HandshakeMessage{}, err
}
resultMap := map[Tag][]byte{}
var dataStart uint32
for indexPos := 0; indexPos < int(nPairs)*8; indexPos += 8 {
tag := Tag(binary.LittleEndian.Uint32(index[indexPos : indexPos+4]))
dataEnd := binary.LittleEndian.Uint32(index[indexPos+4 : indexPos+8])
dataLen := dataEnd - dataStart
if dataLen > protocol.CryptoParameterMaxLength {
return HandshakeMessage{}, qerr.Error(qerr.CryptoInvalidValueLength, "value too long")
}
data := make([]byte, dataLen)
if _, err := io.ReadFull(r, data); err != nil {
return HandshakeMessage{}, err
}
resultMap[tag] = data
dataStart = dataEnd
}
return HandshakeMessage{
Tag: messageTag,
Data: resultMap}, nil
}
// Write writes a crypto message
func (h HandshakeMessage) Write(b *bytes.Buffer) {
data := h.Data
utils.LittleEndian.WriteUint32(b, uint32(h.Tag))
utils.LittleEndian.WriteUint16(b, uint16(len(data)))
utils.LittleEndian.WriteUint16(b, 0)
// Save current position in the buffer, so that we can update the index in-place later
indexStart := b.Len()
indexData := make([]byte, 8*len(data))
b.Write(indexData) // Will be updated later
offset := uint32(0)
for i, t := range h.getTagsSorted() {
v := data[t]
b.Write(v)
offset += uint32(len(v))
binary.LittleEndian.PutUint32(indexData[i*8:], uint32(t))
binary.LittleEndian.PutUint32(indexData[i*8+4:], offset)
}
// Now we write the index data for real
copy(b.Bytes()[indexStart:], indexData)
}
func (h *HandshakeMessage) getTagsSorted() []Tag {
tags := make([]Tag, len(h.Data))
i := 0
for t := range h.Data {
tags[i] = t
i++
}
sort.Slice(tags, func(i, j int) bool {
return tags[i] < tags[j]
})
return tags
}
func (h HandshakeMessage) String() string {
var pad string
res := tagToString(h.Tag) + ":\n"
for _, tag := range h.getTagsSorted() {
if tag == TagPAD {
pad = fmt.Sprintf("\t%s: (%d bytes)\n", tagToString(tag), len(h.Data[tag]))
} else {
res += fmt.Sprintf("\t%s: %#v\n", tagToString(tag), string(h.Data[tag]))
}
}
if len(pad) > 0 {
res += pad
}
return res
}
func tagToString(tag Tag) string {
b := make([]byte, 4)
binary.LittleEndian.PutUint32(b, uint32(tag))
for i := range b {
if b[i] == 0 {
b[i] = ' '
}
}
return string(b)
}