sing-box/inbound/dns.go
2022-07-11 12:56:57 +08:00

115 lines
3.3 KiB
Go

package inbound
import (
"context"
"encoding/binary"
"io"
"net"
"github.com/sagernet/sing-box/adapter"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing/common"
"github.com/sagernet/sing/common/buf"
N "github.com/sagernet/sing/common/network"
"golang.org/x/net/dns/dnsmessage"
)
func NewDNSConnection(ctx context.Context, router adapter.Router, logger log.Logger, conn net.Conn, metadata adapter.InboundContext) error {
ctx = adapter.WithContext(ctx, &metadata)
_buffer := buf.StackNewSize(1024)
defer common.KeepAlive(_buffer)
buffer := common.Dup(_buffer)
defer buffer.Release()
for {
var queryLength uint16
err := binary.Read(conn, binary.BigEndian, &queryLength)
if err != nil {
return err
}
if queryLength > 1024 {
return io.ErrShortBuffer
}
buffer.FullReset()
_, err = buffer.ReadFullFrom(conn, int(queryLength))
if err != nil {
return err
}
var message dnsmessage.Message
err = message.Unpack(buffer.Bytes())
if err != nil {
return err
}
if len(message.Questions) > 0 {
question := message.Questions[0]
metadata.Domain = string(question.Name.Data[:question.Name.Length-1])
logger.WithContext(ctx).Debug("inbound dns query ", formatDNSQuestion(question), " from ", metadata.Source)
}
go func() error {
response, err := router.Exchange(ctx, &message)
if err != nil {
return err
}
_responseBuffer := buf.StackNewSize(1024)
defer common.KeepAlive(_responseBuffer)
responseBuffer := common.Dup(_responseBuffer)
defer responseBuffer.Release()
responseBuffer.Resize(2, 0)
n, err := response.AppendPack(responseBuffer.Index(0))
if err != nil {
return err
}
responseBuffer.Truncate(len(n))
binary.BigEndian.PutUint16(responseBuffer.ExtendHeader(2), uint16(len(n)))
_, err = conn.Write(responseBuffer.Bytes())
return err
}()
}
}
func NewDNSPacketConnection(ctx context.Context, router adapter.Router, logger log.Logger, conn N.PacketConn, metadata adapter.InboundContext) error {
ctx = adapter.WithContext(ctx, &metadata)
_buffer := buf.StackNewSize(1024)
defer common.KeepAlive(_buffer)
buffer := common.Dup(_buffer)
defer buffer.Release()
for {
buffer.FullReset()
destination, err := conn.ReadPacket(buffer)
if err != nil {
return err
}
var message dnsmessage.Message
err = message.Unpack(buffer.Bytes())
if err != nil {
return err
}
if len(message.Questions) > 0 {
question := message.Questions[0]
metadata.Domain = string(question.Name.Data[:question.Name.Length-1])
logger.WithContext(ctx).Debug("inbound dns query ", formatDNSQuestion(question), " from ", metadata.Source)
}
go func() error {
response, err := router.Exchange(ctx, &message)
if err != nil {
return err
}
_responseBuffer := buf.StackNewSize(1024)
defer common.KeepAlive(_responseBuffer)
responseBuffer := common.Dup(_responseBuffer)
defer responseBuffer.Release()
n, err := response.AppendPack(responseBuffer.Index(0))
if err != nil {
return err
}
responseBuffer.Truncate(len(n))
err = conn.WritePacket(responseBuffer, destination)
return err
}()
}
}
func formatDNSQuestion(question dnsmessage.Question) string {
return string(question.Name.Data[:question.Name.Length-1]) + " " + question.Type.String()[4:] + " " + question.Class.String()[5:]
}