VictoriaMetrics/lib/handshake/buffered_conn.go
Roman Khavronenko 27a5461785
lib/handshake: check for deadline in Read and Write methods (#5327)
The buffered connection could have exceeded the underlying connection
deadline during reading or writing to an internal buffer.
With this change, buffered connection struct additionally checks
for a deadline in Read/Write methods.

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-11-16 16:33:40 +01:00

108 lines
2.4 KiB
Go

package handshake
import (
"bufio"
"fmt"
"io"
"net"
"os"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding/zstd"
)
type bufferedWriter interface {
Write(p []byte) (int, error)
Flush() error
}
// BufferedConn is a net.Conn with Flush suport.
type BufferedConn struct {
net.Conn
br io.Reader
bw bufferedWriter
deadline time.Time
}
const bufferSize = 64 * 1024
// newBufferedConn returns buffered connection with the given compression level.
func newBufferedConn(c net.Conn, compressionLevel int, isReadCompressed bool) *BufferedConn {
bc := &BufferedConn{
Conn: c,
}
if compressionLevel <= 0 {
bc.bw = bufio.NewWriterSize(c, bufferSize)
} else {
bc.bw = zstd.NewWriterLevel(c, compressionLevel)
}
if !isReadCompressed {
bc.br = bufio.NewReaderSize(c, bufferSize)
} else {
bc.br = zstd.NewReader(c)
}
return bc
}
// SetDeadline sets the read and write deadlines associated with the connection.
// Deadline is checked on each Read call.
func (bc *BufferedConn) SetDeadline(t time.Time) error {
bc.deadline = t
return bc.Conn.SetDeadline(t)
}
// Read reads up to len(p) from bc to p.
func (bc *BufferedConn) Read(p []byte) (int, error) {
startTime := time.Now()
if startTime.After(bc.deadline) {
return 0, os.ErrDeadlineExceeded
}
n, err := bc.br.Read(p)
if err != nil && err != io.EOF {
err = fmt.Errorf("cannot read data in %.3f seconds: %w", time.Since(startTime).Seconds(), err)
}
return n, err
}
// Write writes p to bc.
//
// Do not forget to call Flush if needed.
func (bc *BufferedConn) Write(p []byte) (int, error) {
startTime := time.Now()
if startTime.After(bc.deadline) {
return 0, os.ErrDeadlineExceeded
}
n, err := bc.bw.Write(p)
if err != nil {
err = fmt.Errorf("cannot write data in %.3f seconds: %w", time.Since(startTime).Seconds(), err)
}
return n, err
}
// Close closes bc.
func (bc *BufferedConn) Close() error {
// Close the Conn at first. It is expected that all the required data
// is already flushed to the Conn.
err := bc.Conn.Close()
bc.Conn = nil
if zr, ok := bc.br.(*zstd.Reader); ok {
zr.Release()
}
bc.br = nil
if zw, ok := bc.bw.(*zstd.Writer); ok {
// Do not call zw.Close(), since we already closed the underlying conn.
zw.Release()
}
bc.bw = nil
return err
}
// Flush flushes internal write buffers to the underlying conn.
func (bc *BufferedConn) Flush() error {
return bc.bw.Flush()
}