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chore: share RelayDnsPacket function code

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This commit is contained in:
wwqgtxx
2024-03-04 22:12:08 +08:00
parent fe4acebb8b
commit 8b9813079b
3 changed files with 102 additions and 108 deletions
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88
listener/sing_tun/dns.go
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@@ -2,29 +2,21 @@ package sing_tun
import (
"context"
"encoding/binary"
"io"
"net"
"net/netip"
"sync"
"time"
"github.com/metacubex/mihomo/common/pool"
"github.com/metacubex/mihomo/component/resolver"
"github.com/metacubex/mihomo/listener/sing"
"github.com/metacubex/mihomo/log"
D "github.com/miekg/dns"
"github.com/sagernet/sing/common/buf"
"github.com/sagernet/sing/common/bufio"
M "github.com/sagernet/sing/common/metadata"
"github.com/sagernet/sing/common/network"
)
const DefaultDnsReadTimeout = time.Second * 10
const DefaultDnsRelayTimeout = time.Second * 5
type ListenerHandler struct {
*sing.ListenerHandler
DnsAdds []netip.AddrPort
@@ -45,61 +37,11 @@ func (h *ListenerHandler) ShouldHijackDns(targetAddr netip.AddrPort) bool {
func (h *ListenerHandler) NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error {
if h.ShouldHijackDns(metadata.Destination.AddrPort()) {
log.Debugln("[DNS] hijack tcp:%s", metadata.Destination.String())
buff := pool.Get(pool.UDPBufferSize)
defer func() {
_ = pool.Put(buff)
_ = conn.Close()
}()
for {
if conn.SetReadDeadline(time.Now().Add(DefaultDnsReadTimeout)) != nil {
break
}
length := uint16(0)
if err := binary.Read(conn, binary.BigEndian, &length); err != nil {
break
}
if int(length) > len(buff) {
break
}
n, err := io.ReadFull(conn, buff[:length])
if err != nil {
break
}
err = func() error {
ctx, cancel := context.WithTimeout(ctx, DefaultDnsRelayTimeout)
defer cancel()
inData := buff[:n]
msg, err := RelayDnsPacket(ctx, inData, buff)
if err != nil {
return err
}
err = binary.Write(conn, binary.BigEndian, uint16(len(msg)))
if err != nil {
return err
}
_, err = conn.Write(msg)
if err != nil {
return err
}
return nil
}()
if err != nil {
return err
}
}
return nil
return resolver.RelayDnsConn(ctx, conn)
}
return h.ListenerHandler.NewConnection(ctx, conn, metadata)
}
const SafeDnsPacketSize = 2 * 1024 // safe size which is 1232 from https://dnsflagday.net/2020/, so 2048 is enough
func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.PacketConn, metadata M.Metadata) error {
if h.ShouldHijackDns(metadata.Destination.AddrPort()) {
log.Debugln("[DNS] hijack udp:%s from %s", metadata.Destination.String(), metadata.Source.String())
@@ -114,7 +56,7 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
rwOptions := network.ReadWaitOptions{
FrontHeadroom: network.CalculateFrontHeadroom(conn),
RearHeadroom: network.CalculateRearHeadroom(conn),
MTU: SafeDnsPacketSize,
MTU: resolver.SafeDnsPacketSize,
}
readWaiter, isReadWaiter := bufio.CreatePacketReadWaiter(conn)
if isReadWaiter {
@@ -126,7 +68,7 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
dest M.Socksaddr
err error
)
_ = conn.SetReadDeadline(time.Now().Add(DefaultDnsReadTimeout))
_ = conn.SetReadDeadline(time.Now().Add(resolver.DefaultDnsReadTimeout))
readBuff = nil // clear last loop status, avoid repeat release
if isReadWaiter {
readBuff, dest, err = readWaiter.WaitReadPacket()
@@ -147,15 +89,15 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
return err
}
go func() {
ctx, cancel := context.WithTimeout(ctx, DefaultDnsRelayTimeout)
ctx, cancel := context.WithTimeout(ctx, resolver.DefaultDnsRelayTimeout)
defer cancel()
inData := readBuff.Bytes()
writeBuff := readBuff
writeBuff.Resize(writeBuff.Start(), 0)
if len(writeBuff.FreeBytes()) < SafeDnsPacketSize { // only create a new buffer when space don't enough
if len(writeBuff.FreeBytes()) < resolver.SafeDnsPacketSize { // only create a new buffer when space don't enough
writeBuff = rwOptions.NewPacketBuffer()
}
msg, err := RelayDnsPacket(ctx, inData, writeBuff.FreeBytes())
msg, err := resolver.RelayDnsPacket(ctx, inData, writeBuff.FreeBytes())
if writeBuff != readBuff {
readBuff.Release()
}
@@ -182,21 +124,3 @@ func (h *ListenerHandler) NewPacketConnection(ctx context.Context, conn network.
}
return h.ListenerHandler.NewPacketConnection(ctx, conn, metadata)
}
func RelayDnsPacket(ctx context.Context, payload []byte, target []byte) ([]byte, error) {
msg := &D.Msg{}
if err := msg.Unpack(payload); err != nil {
return nil, err
}
r, err := resolver.ServeMsg(ctx, msg)
if err != nil {
m := new(D.Msg)
m.SetRcode(msg, D.RcodeServerFailure)
return m.PackBuffer(target)
}
r.SetRcode(msg, r.Rcode)
r.Compress = true
return r.PackBuffer(target)
}