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sniffer.go
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/
sniffer.go
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/*
* SPDX-License-Identifier: AGPL-3.0-only
* Copyright (c) 2022-2024, daeuniverse Organization <dae@v2raya.org>
*/
package sniffing
import (
"context"
"io"
"sync"
"time"
"github.com/daeuniverse/dae/component/sniffing/internal/quicutils"
"github.com/daeuniverse/softwind/pool"
"github.com/daeuniverse/softwind/pool/bytes"
)
type Sniffer struct {
// Stream
stream bool
r io.Reader
dataReady chan struct{}
dataError error
// Common
sniffed string
buf *bytes.Buffer
readMu sync.Mutex
ctx context.Context
cancel func()
// Packet
data [][]byte
needMore bool
quicNextRead int
quicCryptos []*quicutils.CryptoFrameOffset
}
func NewStreamSniffer(r io.Reader, bufSize int, timeout time.Duration) *Sniffer {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
buffer := pool.GetBuffer()
buffer.Grow(AssumedTlsClientHelloMaxLength)
buffer.Reset()
s := &Sniffer{
stream: true,
r: r,
buf: buffer,
dataReady: make(chan struct{}),
ctx: ctx,
cancel: cancel,
}
return s
}
func NewPacketSniffer(data []byte, timeout time.Duration) *Sniffer {
buffer := pool.GetBuffer()
buffer.Write(data)
ctx, cancel := context.WithTimeout(context.Background(), timeout)
s := &Sniffer{
stream: false,
r: nil,
buf: buffer,
data: [][]byte{buffer.Bytes()},
dataReady: make(chan struct{}),
ctx: ctx,
cancel: cancel,
}
return s
}
type sniff func() (d string, err error)
func sniffGroup(sniffs ...sniff) (d string, err error) {
for _, sniffer := range sniffs {
d, err = sniffer()
if err == nil {
return d, nil
}
if err != ErrNotApplicable {
return "", err
}
}
return "", ErrNotApplicable
}
func (s *Sniffer) SniffTcp() (d string, err error) {
if s.sniffed != "" {
return s.sniffed, nil
}
defer func() {
if err == nil {
s.sniffed = d
}
}()
s.readMu.Lock()
defer s.readMu.Unlock()
if s.stream {
go func() {
// Read once.
_, err := s.buf.ReadFromOnce(s.r)
if err != nil {
s.dataError = err
}
close(s.dataReady)
}()
// Waiting 100ms for data.
select {
case <-s.dataReady:
if s.dataError != nil {
return "", s.dataError
}
case <-s.ctx.Done():
return "", ErrNotApplicable
}
} else {
close(s.dataReady)
}
if s.buf.Len() == 0 {
return "", ErrNotApplicable
}
return sniffGroup(
// Most sniffable traffic is TLS, thus we sniff it first.
s.SniffTls,
s.SniffHttp,
)
}
func (s *Sniffer) SniffUdp() (d string, err error) {
if s.sniffed != "" {
return s.sniffed, nil
}
defer func() {
if err == nil {
s.sniffed = d
}
}()
defer func() {
if err == nil {
s.sniffed = d
}
}()
s.readMu.Lock()
defer s.readMu.Unlock()
// Always ready.
select {
case <-s.dataReady:
default:
close(s.dataReady)
}
if s.buf.Len() == 0 {
return "", ErrNotApplicable
}
return sniffGroup(
s.SniffQuic,
)
}
func (s *Sniffer) AppendData(data []byte) {
s.needMore = false
ori := s.buf.Len()
s.buf.Write(data)
s.data = append(s.data, s.buf.Bytes()[ori:])
}
func (s *Sniffer) Data() [][]byte {
return s.data
}
func (s *Sniffer) NeedMore() bool {
return s.needMore
}
func (s *Sniffer) Read(p []byte) (n int, err error) {
<-s.dataReady
s.readMu.Lock()
defer s.readMu.Unlock()
if s.dataError != nil {
n, _ = s.buf.Read(p)
return n, s.dataError
}
if s.buf.Len() > 0 {
// Read buf first.
return s.buf.Read(p)
}
if !s.stream {
return 0, io.EOF
}
return s.r.Read(p)
}
func (s *Sniffer) Close() (err error) {
select {
case <-s.ctx.Done():
default:
s.cancel()
if s.buf.Len() == 0 {
pool.PutBuffer(s.buf)
}
}
return nil
}