eburet-oss/sing-tun-lx
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

ping: Add destination rewriter

Browse source
This commit is contained in:
世界 2025-09-11 18:51:00 +08:00
parent 960457abba
commit 0381a06643
No known key found for this signature in database
GPG key ID: CD109927C34A63C4
3 changed files with 88 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

150
ping/rewriter.go
View file

@ -1,150 +0,0 @@
package ping
import (
"context"
"net/netip"
"sync"
"github.com/sagernet/sing-tun"
"github.com/sagernet/sing-tun/internal/gtcpip/header"
"github.com/sagernet/sing/common/logger"
)
type Rewriter struct {
ctx context.Context
logger logger.ContextLogger
access sync.RWMutex
sessions map[tun.DirectRouteSession]tun.DirectRouteContext
sourceAddress map[uint16]netip.Addr
inet4Address netip.Addr
inet6Address netip.Addr
}
func NewRewriter(ctx context.Context, logger logger.ContextLogger, inet4Address netip.Addr, inet6Address netip.Addr) *Rewriter {
return &Rewriter{
ctx: ctx,
logger: logger,
sessions: make(map[tun.DirectRouteSession]tun.DirectRouteContext),
sourceAddress: make(map[uint16]netip.Addr),
inet4Address: inet4Address,
inet6Address: inet6Address,
}
}
func (m *Rewriter) CreateSession(session tun.DirectRouteSession, context tun.DirectRouteContext) {
m.access.Lock()
m.sessions[session] = context
m.access.Unlock()
}
func (m *Rewriter) DeleteSession(session tun.DirectRouteSession) {
m.access.Lock()
delete(m.sessions, session)
m.access.Unlock()
}
func (m *Rewriter) RewritePacket(packet []byte) {
var ipHdr header.Network
var bindAddr netip.Addr
switch header.IPVersion(packet) {
case header.IPv4Version:
ipHdr = header.IPv4(packet)
bindAddr = m.inet4Address
case header.IPv6Version:
ipHdr = header.IPv6(packet)
bindAddr = m.inet6Address
default:
return
}
sourceAddr := ipHdr.SourceAddr()
ipHdr.SetSourceAddr(bindAddr)
if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
}
switch ipHdr.TransportProtocol() {
case header.ICMPv4ProtocolNumber:
icmpHdr := header.ICMPv4(ipHdr.Payload())
m.access.Lock()
m.sourceAddress[icmpHdr.Ident()] = sourceAddr
m.access.Unlock()
m.logger.TraceContext(m.ctx, "write ICMPv4 echo request from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
case header.ICMPv6ProtocolNumber:
icmpHdr := header.ICMPv6(ipHdr.Payload())
icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
Header: icmpHdr,
Src: ipHdr.SourceAddressSlice(),
Dst: ipHdr.DestinationAddressSlice(),
}))
m.access.Lock()
m.sourceAddress[icmpHdr.Ident()] = sourceAddr
m.access.Unlock()
m.logger.TraceContext(m.ctx, "write ICMPv6 echo request from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
}
}
func (m *Rewriter) WriteBack(packet []byte) (bool, error) {
var ipHdr header.Network
var routeSession tun.DirectRouteSession
switch header.IPVersion(packet) {
case header.IPv4Version:
ipHdr = header.IPv4(packet)
routeSession.Destination = ipHdr.SourceAddr()
case header.IPv6Version:
ipHdr = header.IPv6(packet)
routeSession.Destination = ipHdr.SourceAddr()
default:
return false, nil
}
switch ipHdr.TransportProtocol() {
case header.ICMPv4ProtocolNumber:
icmpHdr := header.ICMPv4(ipHdr.Payload())
m.access.Lock()
ident := icmpHdr.Ident()
source, loaded := m.sourceAddress[ident]
if !loaded {
m.access.Unlock()
return false, nil
}
delete(m.sourceAddress, icmpHdr.Ident())
m.access.Unlock()
routeSession.Source = source
case header.ICMPv6ProtocolNumber:
icmpHdr := header.ICMPv6(ipHdr.Payload())
m.access.Lock()
ident := icmpHdr.Ident()
source, loaded := m.sourceAddress[ident]
if !loaded {
m.access.Unlock()
return false, nil
}
delete(m.sourceAddress, icmpHdr.Ident())
m.access.Unlock()
routeSession.Source = source
default:
return false, nil
}
m.access.RLock()
context, loaded := m.sessions[routeSession]
m.access.RUnlock()
if !loaded {
return false, nil
}
ipHdr.SetDestinationAddr(routeSession.Source)
if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
}
switch ipHdr.TransportProtocol() {
case header.ICMPv4ProtocolNumber:
icmpHdr := header.ICMPv4(ipHdr.Payload())
m.logger.TraceContext(m.ctx, "read ICMPv4 echo reply from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
case header.ICMPv6ProtocolNumber:
icmpHdr := header.ICMPv6(ipHdr.Payload())
icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
Header: icmpHdr,
Src: ipHdr.SourceAddressSlice(),
Dst: ipHdr.DestinationAddressSlice(),
}))
m.logger.TraceContext(m.ctx, "read ICMPv6 echo reply from ", ipHdr.SourceAddr(), " to ", ipHdr.DestinationAddr(), " id ", icmpHdr.Ident(), " seq ", icmpHdr.Sequence())
}
return true, context.WritePacket(packet)
}