101 lines
2.5 KiB
Go
101 lines
2.5 KiB
Go
//go:build with_gvisor && linux
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package tun
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import (
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"fmt"
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"github.com/sagernet/gvisor/pkg/rawfile"
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"github.com/sagernet/gvisor/pkg/tcpip/link/fdbased"
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"github.com/sagernet/gvisor/pkg/tcpip/stack"
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"golang.org/x/sys/unix"
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)
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func init() {
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fdbased.BufConfig = []int{65535}
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}
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var _ GVisorTun = (*NativeTun)(nil)
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func (t *NativeTun) WritePacket(pkt *stack.PacketBuffer) (int, error) {
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iovecs := t.iovecsOutputDefault
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if t.vnetHdr {
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if t.vnetHdrWriteBuf == nil {
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t.vnetHdrWriteBuf = make([]byte, virtioNetHdrLen)
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}
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vnetHdr := virtioNetHdr{}
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if pkt.GSOOptions.Type != stack.GSONone {
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vnetHdr.hdrLen = uint16(pkt.HeaderSize())
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if pkt.GSOOptions.NeedsCsum {
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vnetHdr.flags = unix.VIRTIO_NET_HDR_F_NEEDS_CSUM
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vnetHdr.csumStart = pkt.GSOOptions.L3HdrLen
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vnetHdr.csumOffset = pkt.GSOOptions.CsumOffset
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}
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if uint16(pkt.Data().Size()) > pkt.GSOOptions.MSS {
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switch pkt.GSOOptions.Type {
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case stack.GSOTCPv4:
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vnetHdr.gsoType = unix.VIRTIO_NET_HDR_GSO_TCPV4
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case stack.GSOTCPv6:
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vnetHdr.gsoType = unix.VIRTIO_NET_HDR_GSO_TCPV6
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default:
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panic(fmt.Sprintf("Unknown gso type: %v", pkt.GSOOptions.Type))
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}
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vnetHdr.gsoSize = pkt.GSOOptions.MSS
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}
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}
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if err := vnetHdr.encode(t.vnetHdrWriteBuf); err != nil {
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return 0, err
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}
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iovec := unix.Iovec{Base: &t.vnetHdrWriteBuf[0]}
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iovec.SetLen(virtioNetHdrLen)
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iovecs = append(iovecs, iovec)
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}
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var dataLen int
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for _, packetSlice := range pkt.AsSlices() {
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dataLen += len(packetSlice)
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iovec := unix.Iovec{
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Base: &packetSlice[0],
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}
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iovec.SetLen(len(packetSlice))
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iovecs = append(iovecs, iovec)
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}
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if cap(iovecs) > cap(t.iovecsOutputDefault) {
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t.iovecsOutputDefault = iovecs[:0]
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}
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errno := rawfile.NonBlockingWriteIovec(t.tunFd, iovecs)
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if errno == 0 {
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return dataLen, nil
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} else {
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return 0, errno
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}
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}
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func (t *NativeTun) NewEndpoint() (stack.LinkEndpoint, stack.NICOptions, error) {
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if t.vnetHdr {
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ep, err := fdbased.New(&fdbased.Options{
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FDs: []int{t.tunFd},
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MTU: t.options.MTU,
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GSOMaxSize: gsoMaxSize,
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GRO: true,
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RXChecksumOffload: true,
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TXChecksumOffload: t.txChecksumOffload,
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})
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if err != nil {
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return nil, stack.NICOptions{}, err
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}
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return ep, stack.NICOptions{}, nil
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} else {
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ep, err := fdbased.New(&fdbased.Options{
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FDs: []int{t.tunFd},
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MTU: t.options.MTU,
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RXChecksumOffload: true,
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TXChecksumOffload: t.txChecksumOffload,
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})
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if err != nil {
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return nil, stack.NICOptions{}, err
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}
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return ep, stack.NICOptions{}, nil
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}
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}
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