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stream.go
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stream.go
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package minq
import (
"encoding/hex"
"fmt"
"io"
)
// SendStreamState is the state of a SendStream
type SendStreamState uint8
// SendStreamState values. Not all of these are tracked
const (
SendStreamStateOpen = SendStreamState(0)
SendStreamStateSend = SendStreamState(1)
SendStreamStateCloseQueued = SendStreamState(2) // Not in the spec
SendStreamStateDataSent = SendStreamState(3)
SendStreamStateResetSent = SendStreamState(4)
SendStreamStateDataRecvd = SendStreamState(5) // Not tracked
SendStreamStateResetRecvd = SendStreamState(6) // Not tracked
)
// String produces a nice string from a SendStreamState.
func (s SendStreamState) String() string {
switch s {
case SendStreamStateOpen:
return "SendStreamStateOpen"
case SendStreamStateSend:
return "SendStreamStateSend"
case SendStreamStateCloseQueued:
return "SendStreamStateCloseQueued"
case SendStreamStateDataSent:
return "SendStreamStateDataSent"
case SendStreamStateResetSent:
return "SendStreamStateResetSent"
case SendStreamStateDataRecvd:
return "SendStreamStateDataRecvd"
case SendStreamStateResetRecvd:
return "SendStreamStateResetRecvd"
default:
panic("Unknown SendStreamState")
}
}
// RecvStreamState is the state of a RecvStream
type RecvStreamState uint8
// RecvStreamState values. Not all of these are tracked.
const (
RecvStreamStateRecv = RecvStreamState(0)
RecvStreamStateSizeKnown = RecvStreamState(1)
RecvStreamStateDataRecvd = RecvStreamState(2) // Not tracked
RecvStreamStateResetRecvd = RecvStreamState(3)
RecvStreamStateDataRead = RecvStreamState(4)
RecvStreamStateResetRead = RecvStreamState(5)
)
// String produces a nice string from a RecvStreamState.
func (s RecvStreamState) String() string {
switch s {
case RecvStreamStateRecv:
return "RecvStreamStateRecv"
case RecvStreamStateSizeKnown:
return "RecvStreamStateSizeKnown"
case RecvStreamStateDataRecvd:
return "RecvStreamStateDataRecvd"
case RecvStreamStateResetRecvd:
return "RecvStreamStateResetRecvd"
case RecvStreamStateDataRead:
return "RecvStreamStateDataRead"
case RecvStreamStateResetRead:
return "RecvStreamStateResetRead"
default:
panic("Unknown RecvStreamState")
}
}
// The structure here is a little convoluted.
//
// There are three primary interfaces: SendStream, RecvStream, and Stream. These
// all implement hasIdentity and one or both (for Stream) of sendStreamMethods
// or recvStreamMethods.
//
// The implementations are layered.
//
// streamCommon is at the bottom, it includes stuff common to sending and receiving.
//
// sendStreamBase and recvStreamBase add sending and receiving functions. These
// know how to send and receive, but don't know about identifiers or
// connections. This allows them to be tested in isolation.
//
// Those types don't know about connections, so sendStream and recvStream add
// that by mixing in streamWithIdentity. The same applies to stream, which mixes
// both sendStream and recvStream. These include the concrete implementations of
// the interfaces.
type hasIdentity interface {
Id() uint64
}
type sendStreamMethods interface {
io.WriteCloser
Reset(uint16) error
SendState() SendStreamState
}
type sendStreamPrivateMethods interface {
setSendState(SendStreamState)
outstandingQueuedBytes() int
processMaxStreamData(uint64)
outputWritable() []streamChunk
flowControl() flowControl
}
type recvStreamMethods interface {
io.Reader
StopSending(uint16) error
RecvState() RecvStreamState
}
type recvStreamPrivateMethods interface {
setRecvState(RecvStreamState)
handleReset(offset uint64) error
clearReadable() bool
newFrameData(uint64, bool, []byte, *flowControl) error
updateMaxStreamData(bool)
}
// SendStream can send.
type SendStream interface {
hasIdentity
sendStreamMethods
}
type sendStreamPrivate interface {
SendStream
sendStreamPrivateMethods
}
// RecvStream can receive.
type RecvStream interface {
hasIdentity
recvStreamMethods
}
type recvStreamPrivate interface {
RecvStream
recvStreamPrivateMethods
}
// Stream is both a send and receive stream.
type Stream interface {
hasIdentity
sendStreamMethods
recvStreamMethods
}
type streamPrivate interface {
Stream
sendStreamPrivateMethods
recvStreamPrivateMethods
}
type streamChunk struct {
offset uint64
last bool
data []byte
}
func (sc streamChunk) String() string {
return fmt.Sprintf("chunk(offset=%v, len=%v, last=%v)", sc.offset, len(sc.data), sc.last)
}
type streamCommon struct {
log loggingFunction
chunks []streamChunk
fc flowControl
readOffset uint64
}
func (s *streamCommon) insertSortedChunk(offset uint64, last bool, payload []byte) {
c := streamChunk{offset, last, dup(payload)}
s.log(logTypeStream, "insert %v, current offset=%v", c, s.fc.used)
s.log(logTypeTrace, "payload %v", hex.EncodeToString(payload))
if len(payload) == 0 && !last && offset != 0 {
// Empty frame, ignore
return
}
// First check if we can append the new slice at the end
if nchunks := len(s.chunks); nchunks == 0 || offset > s.chunks[nchunks-1].offset {
s.chunks = append(s.chunks, c)
} else {
// Otherwise find out where it should go
var i int
for i = 0; i < nchunks; i++ {
if offset < s.chunks[i].offset {
break
}
}
// This may not be the fastest way to do this splice.
tmp := make([]streamChunk, 0, nchunks+1)
tmp = append(tmp, s.chunks[:i]...)
tmp = append(tmp, c)
tmp = append(tmp, s.chunks[i:]...)
s.chunks = tmp
}
s.log(logTypeStream, "Stream now has %v chunks", len(s.chunks))
}
type sendStreamBase struct {
streamCommon
state SendStreamState
}
func (s *sendStreamBase) setSendState(state SendStreamState) {
if state != s.state {
s.log(logTypeStream, "set state %v->%v", s.state, state)
s.state = state
}
}
// SendState returns the current state of the receive stream.
func (s *sendStreamBase) SendState() SendStreamState {
return s.state
}
func (s *sendStreamBase) queue(payload []byte, cfc *flowControl) (int, error) {
s.log(logTypeStream, "queueing %v bytes, flow control %v %v", len(payload), &s.fc, cfc)
offset := s.fc.used
allowed := s.fc.take(cfc, uint64(len(payload)))
s.log(logTypeFlowControl, "flow control consumed %v %v", &s.fc, cfc)
if allowed == 0 {
s.log(logTypeFlowControl, "blocked write")
return 0, ErrorWouldBlock
}
payload = payload[:allowed]
s.insertSortedChunk(offset, false, payload)
return int(allowed), nil
}
func (s *sendStreamBase) write(data []byte, connectionFlowControl *flowControl) (int, error) {
switch s.state {
case SendStreamStateOpen:
s.setSendState(SendStreamStateSend)
// Allow a zero-octet write on a stream that hasn't been opened.
if len(data) == 0 {
return s.queue(data, connectionFlowControl)
}
case SendStreamStateSend:
// OK to send
default:
return 0, ErrorStreamIsClosed
}
written := 0
for len(data) > 0 {
tocpy := 1024
if tocpy > len(data) {
tocpy = len(data)
}
n, err := s.queue(data[:tocpy], connectionFlowControl)
if (err == ErrorWouldBlock) && (written > 0) {
s.log(logTypeFlowControl, "write flow control blocked at offset %d", s.fc.used)
break
}
if err != nil {
return written, err
}
written += n
data = data[tocpy:]
}
s.log(logTypeTrace, "wrote %d bytes", written)
return written, nil
}
func (s *sendStreamBase) outstandingQueuedBytes() int {
n := 0
for _, ch := range s.chunks {
n += len(ch.data)
}
return n
}
func (s *sendStreamBase) flowControl() flowControl {
return s.fc
}
// Push out all pending frames. Set the stream state if the end of the stream is available.
func (s *sendStreamBase) outputWritable() []streamChunk {
s.log(logTypeStream, "outputWritable, chunks=%v current max offset=%d)", len(s.chunks), s.fc.max)
for _, ch := range s.chunks {
if ch.last {
s.setSendState(SendStreamStateDataSent)
}
}
out := s.chunks
s.chunks = nil
return out
}
func (s *sendStreamBase) processMaxStreamData(offset uint64) {
s.fc.update(offset)
}
func (s *sendStreamBase) close() {
switch s.state {
case SendStreamStateOpen, SendStreamStateSend:
s.insertSortedChunk(s.fc.used, true, nil)
s.setSendState(SendStreamStateCloseQueued)
default:
// NOOP
}
}
type recvStreamBase struct {
streamCommon
state RecvStreamState
readable bool
}
func (s *recvStreamBase) setRecvState(state RecvStreamState) {
if state != s.state {
s.log(logTypeStream, "set state %v->%v", s.state, state)
s.state = state
}
}
// RecvState returns the current state of the receive stream.
func (s *recvStreamBase) RecvState() RecvStreamState {
return s.state
}
// clearReadable clears the readable flag and returns true if it was set.
func (s *recvStreamBase) clearReadable() bool {
r := s.readable
s.readable = false
return r
}
// Add data to a stream. Return true if this is readable now.
func (s *recvStreamBase) newFrameData(offset uint64, last bool, payload []byte,
cfc *flowControl) error {
s.log(logTypeStream, "new data offset=%d, len=%d", offset, len(payload))
s.log(logTypeFlowControl, "new data flow control %v %v", &s.fc, cfc)
end := offset + uint64(len(payload))
if last {
if end < s.fc.used {
// The end can't be less than what we've received already.
return ErrorFlowControlError
}
if s.state == RecvStreamStateRecv {
s.setRecvState(RecvStreamStateSizeKnown)
}
} else if end > s.fc.used {
if s.state != RecvStreamStateRecv {
// We shouldn't be increasing used in any other state.
return ErrorFlowControlError
}
increase := end - s.fc.used
taken := increase
if !s.fc.unlimited {
taken := s.fc.take(cfc, increase)
s.log(logTypeFlowControl, "taken flow control %d, now %v %v", taken, &s.fc, cfc)
}
if taken < increase {
// We didn't have that much available.
return ErrorFlowControlError
}
} else if end <= s.readOffset {
// No new data here.
return nil
}
if s.state != RecvStreamStateRecv && s.state != RecvStreamStateSizeKnown {
// We shouldn't be receiving in other states.
return nil
}
s.insertSortedChunk(offset, last, payload)
if s.chunks[0].offset <= s.readOffset {
s.readable = true
}
return nil
}
func (s *recvStreamBase) read(b []byte) (int, error) {
s.log(logTypeStream, "Reading len=%v read offset=%v available chunks=%v",
len(b), s.readOffset, len(s.chunks))
if s.state == RecvStreamStateResetRecvd {
s.log(logTypeStream, "Reading stopped for RST_STREAM")
s.setRecvState(RecvStreamStateResetRead)
return 0, ErrorStreamReset
}
read := 0
for len(b) > 0 {
if len(s.chunks) == 0 {
break
}
chunk := s.chunks[0]
s.log(logTypeTrace, "next chunk %v", chunk)
// We have a gap.
if chunk.offset > s.readOffset {
break
}
// Remove leading bytes
remove := s.readOffset - chunk.offset
if remove > uint64(len(chunk.data)) {
// Nothing left.
s.chunks = s.chunks[1:]
continue
}
chunk.offset += remove
chunk.data = chunk.data[remove:]
// Now figure out how much we can read
n := copy(b, chunk.data)
s.log(logTypeTrace, "read %v at offset %v", n, s.readOffset)
chunk.data = chunk.data[n:]
chunk.offset += uint64(n)
s.readOffset += uint64(n)
b = b[n:]
read += n
// This chunk is empty.
if len(chunk.data) == 0 {
s.chunks = s.chunks[1:]
if chunk.last {
s.setRecvState(RecvStreamStateDataRead)
s.chunks = nil
break
}
}
}
// If we have read no data, say we would have blocked.
if read == 0 {
switch s.state {
case RecvStreamStateRecv, RecvStreamStateSizeKnown:
return 0, ErrorWouldBlock
default:
if s.chunks == nil {
return 0, io.EOF
}
return 0, ErrorStreamIsClosed
}
}
s.log(logTypeStream, "Returning %v bytes chunks=%v", read, len(s.chunks))
return read, nil
}
func (s *recvStreamBase) handleReset(offset uint64) error {
switch s.state {
case RecvStreamStateRecv:
s.fc.used = offset
case RecvStreamStateDataRecvd, RecvStreamStateResetRead:
panic("we don't use this state")
case RecvStreamStateSizeKnown, RecvStreamStateDataRead, RecvStreamStateResetRecvd:
if offset != s.fc.used {
return ErrorProtocolViolation
}
default:
panic(fmt.Sprintf("unknown state %v", s.state))
}
s.setRecvState(RecvStreamStateResetRecvd)
s.chunks = nil
return nil
}
// SendStream is a unidirectional stream for sending.
type sendStream struct {
c *Connection
id uint64
sendStreamBase
}
// Compile-time interface check.
var _ SendStream = &sendStream{}
func newSendStream(c *Connection, id uint64, initialMax uint64) sendStreamPrivate {
return &sendStream{
c: c, id: id,
sendStreamBase: sendStreamBase{
streamCommon: streamCommon{
log: newStreamLogger(id, "send", c.log),
fc: newFlowControl(initialMax),
},
state: SendStreamStateOpen,
},
}
}
// Id returns the id.
func (s *sendStream) Id() uint64 {
return s.id
}
// Write writes data.
func (s *sendStream) Write(data []byte) (int, error) {
s.log(logTypeStream, "Stream %v: writing %v bytes", s.Id(), len(data))
if s.c.isClosed() {
return 0, ErrorConnIsClosed
}
n, err := s.write(data, &s.c.sendFlowControl)
if err != nil {
if err == ErrorWouldBlock {
s.c.updateStreamBlocked(s)
s.c.updateBlocked()
}
return n, err
}
s.c.sendQueued(false)
return n, nil
}
// Close makes the stream end cleanly.
func (s *sendStream) Close() error {
s.close()
s.c.sendQueued(false)
return nil
}
// Reset abandons writing on the stream.
func (s *sendStream) Reset(code uint16) error {
s.setSendState(SendStreamStateResetSent)
f := newRstStreamFrame(s.id, code, s.fc.used)
return s.c.sendFrame(f)
}
// recvStream is the implementation of a unidirectional stream for receiving.
type recvStream struct {
c *Connection
id uint64
recvStreamBase
}
// Compile-time interface check.
var _ RecvStream = &recvStream{}
func newRecvStream(c *Connection, id uint64, maxStreamData uint64) recvStreamPrivate {
return &recvStream{
c: c, id: id,
recvStreamBase: recvStreamBase{
streamCommon: streamCommon{
log: newStreamLogger(id, "recv", c.log),
fc: newFlowControl(maxStreamData),
},
state: RecvStreamStateRecv,
readable: false,
},
}
}
// Id returns the id.
func (s *recvStream) Id() uint64 {
return s.id
}
// updateMaxStreamData checks the current flow control limit and sends
// MAX_STREAM_DATA as necessary.
func (s *recvStream) updateMaxStreamData(force bool) {
s.log(logTypeFlowControl, "credit flow control %v", &s.fc)
if force || s.fc.remaining() < kInitialMaxStreamData/2 {
s.fc.max = s.readOffset + kInitialMaxData
s.log(logTypeFlowControl, "increased flow control to %v", &s.fc)
s.c.issueStreamCredit(s, s.fc.max)
}
}
// Read implements io.Reader.
func (s *recvStream) Read(b []byte) (int, error) {
if s.c.isClosed() {
return 0, io.EOF
}
n, err := s.read(b)
if err != nil {
return 0, err
}
s.c.amountRead += uint64(n)
// Now issue credit for stream flow control, ...
s.updateMaxStreamData(false)
// ..., connection flow control, ...
s.c.issueCredit(false)
// ..., and streams.
if s.state == RecvStreamStateDataRead {
s.c.issueStreamIdCredit(streamTypeFromId(s.id, s.c.role))
}
return n, nil
}
func (s *recvStream) handleReset(offset uint64) error {
err := s.recvStreamBase.handleReset(offset)
if err != nil {
return err
}
// Pretend that we read this much data.
s.c.amountRead += s.fc.used - s.readOffset
s.readOffset = s.fc.used
s.c.issueCredit(false)
return nil
}
// StopSending requests a reset.
func (s *recvStream) StopSending(code uint16) error {
f := newStopSendingFrame(s.id, code)
return s.c.sendFrame(f)
}
// stream is a bidirectional stream.
type stream struct {
c *Connection
id uint64
sendStreamPrivate
recvStreamPrivate
}
// Compile-time interface check.
var _ Stream = &stream{}
func newStream(c *Connection, id uint64, sendMax uint64, recvMax uint64) streamPrivate {
return &stream{
sendStreamPrivate: newSendStream(c, id, sendMax),
recvStreamPrivate: newRecvStream(c, id, recvMax),
}
}
// Id needs to be overwritten so that the ambiguity between send and receive can be resolved.
func (s *stream) Id() uint64 {
return s.sendStreamPrivate.Id()
}
type streamType uint8
// These values match the low bits of the stream ID for a client, but the low
// bit is flipped for a server.
const (
streamTypeBidirectionalLocal = streamType(0)
streamTypeBidirectionalRemote = streamType(1)
streamTypeUnidirectionalLocal = streamType(2)
streamTypeUnidirectionalRemote = streamType(3)
)
func streamTypeFromId(id uint64, role Role) streamType {
t := id & 3
if role == RoleServer {
t ^= 1
}
return streamType(t)
}
func (t streamType) suffix(role Role) uint64 {
suff := uint64(t)
if role == RoleServer {
suff ^= 1
}
return suff
}
func (t streamType) String() string {
switch t {
case streamTypeBidirectionalLocal:
return "bidirectional local"
case streamTypeBidirectionalRemote:
return "bidirectional remote"
case streamTypeUnidirectionalLocal:
return "unidirectional local"
case streamTypeUnidirectionalRemote:
return "unidirectional remote"
default:
panic("unknown stream type")
}
}
type streamSet struct {
// t is the type of stream relative to the endpoints role
t streamType
// role is the endpoint's role
role Role
// nstreams is the maximum number of streams (as opposed to the maximum ID)
nstreams int
// typeless array of streams because go doesn't have generics
streams []hasIdentity
}
func newStreamSet(t streamType, role Role, nstreams int) *streamSet {
return &streamSet{t, role, nstreams, make([]hasIdentity, 0, nstreams)}
}
func (ss *streamSet) check(id uint64) {
// If sizeof(int) == sizeof(uint64), then we will never overflow int.
assert(^uint64(0) == uint64(^uint(0)))
assert((id & (^uint64(0) >> 2)) == id) // The top bits should be clear.
assert((id & 3) == ss.t.suffix(ss.role))
}
func (ss *streamSet) index(id uint64) int {
ss.check(id)
return int(id >> 2)
}
func (ss *streamSet) id(index int) uint64 {
assert(index >= 0)
return uint64(index<<2) | uint64(ss.t.suffix(ss.role))
}
type flowControl struct {
unlimited bool
max uint64
used uint64
}
func newFlowControl(initialMax uint64) flowControl {
fc := flowControl{false, initialMax, 0}
if initialMax == ^uint64(0) {
fc.unlimited = true
}
return fc
}
func (fc *flowControl) String() string {
if fc.unlimited {
return ("Unlimited")
}
return fmt.Sprintf("%d/%d", fc.used, fc.max)
}
func (fc *flowControl) update(max uint64) {
if max > fc.max {
fc.max = max
}
}
func (fc *flowControl) take(other *flowControl, amount uint64) uint64 {
taken := uint64(0)
if !fc.unlimited {
taken = fc.remaining()
if taken > other.remaining() {
taken = other.remaining()
}
} else {
taken = ^uint64(0)
}
if taken > amount {
taken = amount
}
fc.used += taken
// TODO(ekr@rtfm.com): Is this still needed.
if other != nil {
other.used += taken
}
return taken
}
func (fc *flowControl) remaining() uint64 {
return fc.max - fc.used
}
func (ss *streamSet) updateMax(id uint64) {
ss.nstreams = ss.index(id) + 1
}
func (ss *streamSet) credit(n int) uint64 {
ss.nstreams += n
return ss.id(ss.nstreams - 1)
}
func (ss *streamSet) get(id uint64) hasIdentity {
i := ss.index(id)
if i >= len(ss.streams) {
return nil
}
return ss.streams[i]
}
type streamSetCtor func(id uint64) hasIdentity
func (ss *streamSet) create(ctor streamSetCtor) hasIdentity {
i := len(ss.streams)
if i >= ss.nstreams {
return nil
}
ss.streams = append(ss.streams, ctor(ss.id(i)))
return ss.streams[i]
}
func (ss *streamSet) ensure(id uint64, ctor streamSetCtor,
notify func(s hasIdentity)) hasIdentity {
i := ss.index(id)
if i >= ss.nstreams {
return nil
}
if i >= len(ss.streams) {
needed := i - len(ss.streams) + 1
start := len(ss.streams)
ss.streams = append(ss.streams, make([]hasIdentity, needed)...)
for j := start; j < len(ss.streams); j++ {
s := ctor(ss.id(j))
ss.check(s.Id())
ss.streams[j] = s
notify(ss.streams[j])
}
}
return ss.streams[i]
}
func (ss *streamSet) forEach(f func(hasIdentity)) {
for _, s := range ss.streams {
f(s)
}
}