conn, device, tun: implement vectorized I/O plumbing
Accept packet vectors for reading and writing in the tun.Device and conn.Bind interfaces, so that the internal plumbing between these interfaces now passes a vector of packets. Vectors move untouched between these interfaces, i.e. if 128 packets are received from conn.Bind.Read(), 128 packets are passed to tun.Device.Write(). There is no internal buffering. Currently, existing implementations are only adjusted to have vectors of length one. Subsequent patches will improve that. Also, as a related fixup, use the unix and windows packages rather than the syscall package when possible. Co-authored-by: James Tucker <james@tailscale.com> Signed-off-by: James Tucker <james@tailscale.com> Signed-off-by: Jordan Whited <jordan@tailscale.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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committed by
Jason A. Donenfeld
parent
21636207a6
commit
3bb8fec7e4
@@ -8,13 +8,13 @@ package tun
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import (
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"errors"
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"fmt"
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"io"
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"net"
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"os"
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"sync"
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"syscall"
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"unsafe"
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"golang.org/x/net/ipv6"
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"golang.org/x/sys/unix"
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)
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@@ -204,45 +204,43 @@ func (tun *NativeTun) Events() <-chan Event {
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return tun.events
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}
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func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
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func (tun *NativeTun) Read(buffs [][]byte, sizes []int, offset int) (int, error) {
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select {
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case err := <-tun.errors:
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return 0, err
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default:
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buff := buff[offset-4:]
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buff := buffs[0][offset-4:]
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n, err := tun.tunFile.Read(buff[:])
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if n < 4 {
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return 0, err
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}
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return n - 4, err
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sizes[0] = n - 4
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return 1, err
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}
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}
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func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
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// reserve space for header
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buff = buff[offset-4:]
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// add packet information header
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buff[0] = 0x00
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buff[1] = 0x00
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buff[2] = 0x00
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if buff[4]>>4 == ipv6.Version {
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buff[3] = unix.AF_INET6
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} else {
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buff[3] = unix.AF_INET
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func (tun *NativeTun) Write(buffs [][]byte, offset int) (int, error) {
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if offset < 4 {
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return 0, io.ErrShortBuffer
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}
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// write
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return tun.tunFile.Write(buff)
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}
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func (tun *NativeTun) Flush() error {
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// TODO: can flushing be implemented by buffering and using sendmmsg?
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return nil
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for i, buf := range buffs {
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buf = buf[offset-4:]
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buf[0] = 0x00
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buf[1] = 0x00
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buf[2] = 0x00
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switch buf[4] >> 4 {
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case 4:
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buf[3] = unix.AF_INET
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case 6:
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buf[3] = unix.AF_INET6
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default:
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return i, unix.EAFNOSUPPORT
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}
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if _, err := tun.tunFile.Write(buf); err != nil {
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return i, err
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}
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}
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return len(buffs), nil
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}
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func (tun *NativeTun) Close() error {
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@@ -329,3 +327,7 @@ func (tun *NativeTun) MTU() (int, error) {
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return int(*(*int32)(unsafe.Pointer(&ifr.MTU))), nil
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}
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func (tun *NativeTun) BatchSize() int {
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return 1
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}
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