Files
rtsp-simple-server/internal/protocols/rtmp/rawmessage/reader.go
2024-01-03 21:13:20 +01:00

325 lines
7.9 KiB
Go

package rawmessage
import (
"bufio"
"errors"
"fmt"
"io"
"time"
"github.com/bluenviron/mediamtx/internal/protocols/rtmp/bytecounter"
"github.com/bluenviron/mediamtx/internal/protocols/rtmp/chunk"
)
var errMoreChunksNeeded = errors.New("more chunks are needed")
const (
maxBodySize = 10 * 1024 * 1024
)
func joinFragments(fragments [][]byte, size uint32) []byte {
ret := make([]byte, size)
n := 0
for _, p := range fragments {
n += copy(ret[n:], p)
}
return ret
}
type readerChunkStream struct {
mr *Reader
curTimestamp uint32
curTimestampAvailable bool
curType uint8
curMessageStreamID uint32
curBodyLen uint32
curBodyFragments [][]byte
curBodyRecv uint32
curTimestampDelta uint32
curTimestampDeltaAvailable bool
hasExtendedTimestamp bool
}
func (rc *readerChunkStream) readChunk(c chunk.Chunk, bodySize uint32, hasExtendedTimestamp bool) error {
err := c.Read(rc.mr.br, bodySize, hasExtendedTimestamp)
if err != nil {
return err
}
// check if an ack is needed
if rc.mr.ackWindowSize != 0 {
count := uint32(rc.mr.bcr.Count())
diff := count - rc.mr.lastAckCount
if diff > (rc.mr.ackWindowSize) {
err := rc.mr.onAckNeeded(count)
if err != nil {
return err
}
rc.mr.lastAckCount += (rc.mr.ackWindowSize)
}
}
return nil
}
func (rc *readerChunkStream) readMessage(typ byte) (*Message, error) {
switch typ {
case 0:
if rc.curBodyRecv != 0 {
return nil, fmt.Errorf("received type 0 chunk but expected type 3 chunk")
}
err := rc.readChunk(&rc.mr.c0, rc.mr.chunkSize, false)
if err != nil {
return nil, err
}
rc.curMessageStreamID = rc.mr.c0.MessageStreamID
rc.curType = rc.mr.c0.Type
rc.curTimestamp = rc.mr.c0.Timestamp
rc.curTimestampAvailable = true
rc.curTimestampDeltaAvailable = false
rc.curBodyLen = rc.mr.c0.BodyLen
rc.hasExtendedTimestamp = rc.mr.c0.Timestamp >= 0xFFFFFF
if rc.curBodyLen > maxBodySize {
return nil, fmt.Errorf("body size (%d) exceeds maximum (%d)", rc.curBodyLen, maxBodySize)
}
le := uint32(len(rc.mr.c0.Body))
if rc.mr.c0.BodyLen != le {
rc.curBodyFragments = append(rc.curBodyFragments, rc.mr.c0.Body)
rc.curBodyRecv = le
return nil, errMoreChunksNeeded
}
rc.mr.msg.Timestamp = time.Duration(rc.mr.c0.Timestamp) * time.Millisecond
rc.mr.msg.Type = rc.mr.c0.Type
rc.mr.msg.MessageStreamID = rc.mr.c0.MessageStreamID
rc.mr.msg.Body = rc.mr.c0.Body
return &rc.mr.msg, nil
case 1:
if !rc.curTimestampAvailable {
return nil, fmt.Errorf("received type 1 chunk without previous chunk")
}
if rc.curBodyRecv != 0 {
return nil, fmt.Errorf("received type 1 chunk but expected type 3 chunk")
}
err := rc.readChunk(&rc.mr.c1, rc.mr.chunkSize, false)
if err != nil {
return nil, err
}
rc.curType = rc.mr.c1.Type
rc.curTimestamp += rc.mr.c1.TimestampDelta
rc.curTimestampDelta = rc.mr.c1.TimestampDelta
rc.curTimestampDeltaAvailable = true
rc.curBodyLen = rc.mr.c1.BodyLen
rc.hasExtendedTimestamp = rc.mr.c1.TimestampDelta >= 0xFFFFFF
if rc.curBodyLen > maxBodySize {
return nil, fmt.Errorf("body size (%d) exceeds maximum (%d)", rc.curBodyLen, maxBodySize)
}
le := uint32(len(rc.mr.c1.Body))
if rc.mr.c1.BodyLen != le {
rc.curBodyFragments = append(rc.curBodyFragments, rc.mr.c1.Body)
rc.curBodyRecv = le
return nil, errMoreChunksNeeded
}
rc.mr.msg.Timestamp = time.Duration(rc.curTimestamp) * time.Millisecond
rc.mr.msg.Type = rc.mr.c1.Type
rc.mr.msg.MessageStreamID = rc.curMessageStreamID
rc.mr.msg.Body = rc.mr.c1.Body
return &rc.mr.msg, nil
case 2:
if !rc.curTimestampAvailable {
return nil, fmt.Errorf("received type 2 chunk without previous chunk")
}
if rc.curBodyRecv != 0 {
return nil, fmt.Errorf("received type 2 chunk but expected type 3 chunk")
}
chunkBodyLen := rc.curBodyLen
if chunkBodyLen > rc.mr.chunkSize {
chunkBodyLen = rc.mr.chunkSize
}
err := rc.readChunk(&rc.mr.c2, chunkBodyLen, false)
if err != nil {
return nil, err
}
rc.curTimestamp += rc.mr.c2.TimestampDelta
rc.curTimestampDelta = rc.mr.c2.TimestampDelta
rc.curTimestampDeltaAvailable = true
rc.hasExtendedTimestamp = rc.mr.c2.TimestampDelta >= 0xFFFFFF
le := uint32(len(rc.mr.c2.Body))
if rc.curBodyLen != le {
rc.curBodyFragments = append(rc.curBodyFragments, rc.mr.c2.Body)
rc.curBodyRecv = le
return nil, errMoreChunksNeeded
}
rc.mr.msg.Timestamp = time.Duration(rc.curTimestamp) * time.Millisecond
rc.mr.msg.Type = rc.curType
rc.mr.msg.MessageStreamID = rc.curMessageStreamID
rc.mr.msg.Body = rc.mr.c2.Body
return &rc.mr.msg, nil
default: // 3
if rc.curBodyRecv != 0 {
chunkBodyLen := rc.curBodyLen - rc.curBodyRecv
if chunkBodyLen > rc.mr.chunkSize {
chunkBodyLen = rc.mr.chunkSize
}
err := rc.readChunk(&rc.mr.c3, chunkBodyLen, rc.hasExtendedTimestamp)
if err != nil {
return nil, err
}
rc.curBodyFragments = append(rc.curBodyFragments, rc.mr.c3.Body)
rc.curBodyRecv += uint32(len(rc.mr.c3.Body))
if rc.curBodyLen != rc.curBodyRecv {
return nil, errMoreChunksNeeded
}
rc.mr.msg.Timestamp = time.Duration(rc.curTimestamp) * time.Millisecond
rc.mr.msg.Type = rc.curType
rc.mr.msg.MessageStreamID = rc.curMessageStreamID
rc.mr.msg.Body = joinFragments(rc.curBodyFragments, rc.curBodyRecv)
rc.curBodyFragments = rc.curBodyFragments[:0]
rc.curBodyRecv = 0
return &rc.mr.msg, nil
}
if !rc.curTimestampDeltaAvailable {
return nil, fmt.Errorf("received type 3 chunk without previous chunk")
}
chunkBodyLen := rc.curBodyLen
if chunkBodyLen > rc.mr.chunkSize {
chunkBodyLen = rc.mr.chunkSize
}
err := rc.readChunk(&rc.mr.c3, chunkBodyLen, rc.hasExtendedTimestamp)
if err != nil {
return nil, err
}
rc.curTimestamp += rc.curTimestampDelta
le := uint32(len(rc.mr.c3.Body))
if rc.curBodyLen != le {
rc.curBodyFragments = append(rc.curBodyFragments, rc.mr.c3.Body)
rc.curBodyRecv = le
return nil, errMoreChunksNeeded
}
rc.mr.msg.Timestamp = time.Duration(rc.curTimestamp) * time.Millisecond
rc.mr.msg.Type = rc.curType
rc.mr.msg.MessageStreamID = rc.curMessageStreamID
rc.mr.msg.Body = rc.mr.c3.Body
return &rc.mr.msg, nil
}
}
// Reader is a raw message reader.
type Reader struct {
bcr *bytecounter.Reader
onAckNeeded func(uint32) error
br *bufio.Reader
chunkSize uint32
ackWindowSize uint32
lastAckCount uint32
msg Message
c0 chunk.Chunk0
c1 chunk.Chunk1
c2 chunk.Chunk2
c3 chunk.Chunk3
chunkStreams map[byte]*readerChunkStream
}
// NewReader allocates a Reader.
func NewReader(
r io.Reader,
bcr *bytecounter.Reader,
onAckNeeded func(uint32) error,
) *Reader {
return &Reader{
bcr: bcr,
br: bufio.NewReader(r),
onAckNeeded: onAckNeeded,
chunkSize: 128,
chunkStreams: make(map[byte]*readerChunkStream),
}
}
// SetChunkSize sets the maximum chunk size.
func (r *Reader) SetChunkSize(v uint32) error {
if v > maxBodySize {
return fmt.Errorf("chunk size (%d) exceeds maximum (%d)", v, maxBodySize)
}
r.chunkSize = v
return nil
}
// SetWindowAckSize sets the window acknowledgement size.
func (r *Reader) SetWindowAckSize(v uint32) {
r.ackWindowSize = v
}
// Read reads a Message.
func (r *Reader) Read() (*Message, error) {
for {
byt, err := r.br.ReadByte()
if err != nil {
return nil, err
}
typ := byt >> 6
chunkStreamID := byt & 0x3F
if chunkStreamID < 2 {
return nil, fmt.Errorf("extended chunk stream IDs are not supported (yet)")
}
rc, ok := r.chunkStreams[chunkStreamID]
if !ok {
rc = &readerChunkStream{mr: r}
r.chunkStreams[chunkStreamID] = rc
}
r.br.UnreadByte() //nolint:errcheck
msg, err := rc.readMessage(typ)
if err != nil {
if errors.Is(err, errMoreChunksNeeded) {
continue
}
return nil, err
}
msg.ChunkStreamID = chunkStreamID
return msg, err
}
}