79 lines
2.3 KiB
Go
79 lines
2.3 KiB
Go
package ping
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import (
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"net/netip"
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"github.com/sagernet/sing-tun"
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"github.com/sagernet/sing-tun/gtcpip/header"
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"github.com/sagernet/sing/common/buf"
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)
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type DestinationWriter struct {
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tun.DirectRouteDestination
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destination netip.Addr
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}
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func NewDestinationWriter(routeDestination tun.DirectRouteDestination, destination netip.Addr) *DestinationWriter {
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return &DestinationWriter{routeDestination, destination}
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}
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func (w *DestinationWriter) WritePacket(packet *buf.Buffer) error {
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var ipHdr header.Network
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switch header.IPVersion(packet.Bytes()) {
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case header.IPv4Version:
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ipHdr = header.IPv4(packet.Bytes())
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case header.IPv6Version:
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ipHdr = header.IPv6(packet.Bytes())
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default:
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return w.DirectRouteDestination.WritePacket(packet)
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}
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ipHdr.SetDestinationAddr(w.destination)
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if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
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ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
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}
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if ipHdr.TransportProtocol() == header.ICMPv6ProtocolNumber {
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icmpHdr := header.ICMPv6(ipHdr.Payload())
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icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
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Header: icmpHdr,
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Src: ipHdr.SourceAddressSlice(),
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Dst: ipHdr.DestinationAddressSlice(),
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}))
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}
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return w.DirectRouteDestination.WritePacket(packet)
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}
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type ContextDestinationWriter struct {
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tun.DirectRouteContext
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destination netip.Addr
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}
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func NewContextDestinationWriter(context tun.DirectRouteContext, destination netip.Addr) *ContextDestinationWriter {
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return &ContextDestinationWriter{
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context, destination,
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}
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}
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func (w *ContextDestinationWriter) WritePacket(packet []byte) error {
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var ipHdr header.Network
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switch header.IPVersion(packet) {
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case header.IPv4Version:
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ipHdr = header.IPv4(packet)
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case header.IPv6Version:
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ipHdr = header.IPv6(packet)
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default:
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return w.DirectRouteContext.WritePacket(packet)
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}
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ipHdr.SetSourceAddr(w.destination)
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if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
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ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
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}
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if ipHdr.TransportProtocol() == header.ICMPv6ProtocolNumber {
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icmpHdr := header.ICMPv6(ipHdr.Payload())
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icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
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Header: icmpHdr,
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Src: ipHdr.SourceAddressSlice(),
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Dst: ipHdr.DestinationAddressSlice(),
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}))
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}
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return w.DirectRouteContext.WritePacket(packet)
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}
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