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stick closer to upstream tun reading code

This commit is contained in:
Josh Bleecher Snyder 2021-06-03 14:03:42 -07:00
parent 001dec84de
commit 78fd2b7880
2 changed files with 19 additions and 5 deletions
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17
net/tstun/wrap.go
View File

@ -315,7 +315,7 @@ func (t *Wrapper) poll() {
if t.isClosed() {
return
}
n, err = t.tdev.Read(t.buffer[:], PacketStartOffset)
n, err = t.read(t.buffer[:], PacketStartOffset)
}
t.sendOutbound(tunReadResult{data: t.buffer[PacketStartOffset : PacketStartOffset+n], err: err})
}
@ -565,6 +565,21 @@ func (t *Wrapper) write(buf []byte, offset int) (int, error) {
return n, err
}
func (t *Wrapper) read(buf []byte, offset int) (n int, err error) {
// TODO: upstream has graceful shutdown error handling here.
buff := buf[offset-4:]
n, err = t.ring.Read(buff[:])
if errors.Is(err, syscall.EBADFD) {
err = os.ErrClosed
}
if n < 4 {
n = 0
} else {
n -= 4
}
return
}
func (t *Wrapper) GetFilter() *filter.Filter {
filt, _ := t.filter.Load().(*filter.Filter)
return filt

7
net/uring/io_uring_linux.go
View File

@ -343,7 +343,7 @@ type fileReq struct {
// Read data into buf[offset:].
// We are allowed to write junk into buf[offset-4:offset].
func (u *File) Read(buf []byte, offset int) (n int, err error) { // read a packet from the device (without any additional headers)
func (u *File) Read(buf []byte) (n int, err error) { // read a packet from the device (without any additional headers)
if u.fd == 0 {
return 0, errors.New("invalid uring.File")
}
@ -353,10 +353,8 @@ func (u *File) Read(buf []byte, offset int) (n int, err error) { // read a packe
return 0, fmt.Errorf("Read: %v", err)
}
r := u.readReqs[idx]
// Ignore the first 4 bytes of r.buf, because it contains TUN IP header, which we don't use.
// TODO: open with NOPI?
rbuf := sliceOf(r.buf, n)
n = copy(buf[offset:], rbuf[4:])
copy(buf, rbuf)
// Queue up a new request.
err = u.submitReadvRequest(int(idx))
if err != nil {
@ -406,6 +404,7 @@ func (u *File) Write(buf []byte) (int, error) {
func (u *File) Close() error {
u.close.Do(func() {
u.file.Close()
// TODO: require kernel 5.5, send an abort SQE, handle aborts gracefully
C.io_uring_queue_exit(u.readRing)
C.io_uring_queue_exit(u.writeRing)
u.readRing = nil