Make fdbased endpoint detachabledetachable-fdbased

Cancel the inbound dispatchers if the endpoint is detached.

Signed-off-by: Mikael Magnusson <mikma@users.sourceforge.net>

4 files changed, 64 insertions, 8 deletions

diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index 2bb1be5d6..01d1ad3c8 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -57,6 +57,7 @@ import (
 // NetworkDispatcher.
 type linkDispatcher interface {
 	dispatch() (bool, tcpip.Error)
+	Cancel()
 }
 
 // PacketDispatchMode are the various supported methods of receiving and
@@ -322,9 +323,24 @@ func isSocketFD(fd int) (bool, error) {
 	return (stat.Mode & unix.S_IFSOCK) == unix.S_IFSOCK, nil
 }
 
+func (e *endpoint) detach() {
+	for _, d := range e.inboundDispatchers {
+		d.Cancel()
+	}
+	e.Wait()
+}
+
 // Attach launches the goroutine that reads packets from the file descriptor and
 // dispatches them via the provided dispatcher.
 func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	if (e.dispatcher != nil) {
+		e.detach()
+	}
+
+	if (dispatcher == nil) {
+		return
+	}
+
 	e.dispatcher = dispatcher
 	// Link endpoints are not savable. When transportation endpoints are
 	// saved, they stop sending outgoing packets and all incoming packets
diff --git a/pkg/tcpip/link/fdbased/mmap.go b/pkg/tcpip/link/fdbased/mmap.go
index 5d698a5e9..3c95143c9 100644
--- a/pkg/tcpip/link/fdbased/mmap.go
+++ b/pkg/tcpip/link/fdbased/mmap.go
@@ -160,6 +160,10 @@ func (d *packetMMapDispatcher) readMMappedPacket() ([]byte, tcpip.Error) {
 	return pkt, nil
 }
 
+func (d *packetMMapDispatcher) Cancel() {
+	// TODO
+}
+
 // dispatch reads packets from an mmaped ring buffer and dispatches them to the
 // network stack.
 func (d *packetMMapDispatcher) dispatch() (bool, tcpip.Error) {
diff --git a/pkg/tcpip/link/fdbased/packet_dispatchers.go b/pkg/tcpip/link/fdbased/packet_dispatchers.go
index a7adf822b..9deee81ac 100644
--- a/pkg/tcpip/link/fdbased/packet_dispatchers.go
+++ b/pkg/tcpip/link/fdbased/packet_dispatchers.go
@@ -17,6 +17,8 @@
 package fdbased
 
 import (
+	"os"
+
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -124,18 +126,29 @@ type readVDispatcher struct {
 
 	// buf is the iovec buffer that contains the packet contents.
 	buf *iovecBuffer
+
+	cancelRead *os.File
+	cancelWrite *os.File
 }
 
 func newReadVDispatcher(fd int, e *endpoint) (linkDispatcher, error) {
-	d := &readVDispatcher{fd: fd, e: e}
+	cancelRead, cancelWrite, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+	d := &readVDispatcher{fd: fd, e: e, cancelRead: cancelRead, cancelWrite: cancelWrite}
 	skipsVnetHdr := d.e.Capabilities()&stack.CapabilityHardwareGSO != 0
 	d.buf = newIovecBuffer(BufConfig, skipsVnetHdr)
 	return d, nil
 }
 
+func (d *readVDispatcher) Cancel() {
+	d.cancelWrite.Write([]byte{0})
+}
+
 // dispatch reads one packet from the file descriptor and dispatches it.
 func (d *readVDispatcher) dispatch() (bool, tcpip.Error) {
-	n, err := rawfile.BlockingReadv(d.fd, d.buf.nextIovecs())
+	n, err := rawfile.BlockingReadvWithCancel(d.fd, d.buf.nextIovecs(), d.cancelRead)
 	if n == 0 || err != nil {
 		return false, err
 	}
@@ -219,6 +232,10 @@ func newRecvMMsgDispatcher(fd int, e *endpoint) (linkDispatcher, error) {
 	return d, nil
 }
 
+func (d *recvMMsgDispatcher) Cancel() {
+	// TODO
+}
+
 // recvMMsgDispatch reads more than one packet at a time from the file
 // descriptor and dispatches it.
 func (d *recvMMsgDispatcher) dispatch() (bool, tcpip.Error) {
diff --git a/pkg/tcpip/link/rawfile/rawfile_unsafe.go b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
index ba92aedbc..591cb4279 100644
--- a/pkg/tcpip/link/rawfile/rawfile_unsafe.go
+++ b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
@@ -19,6 +19,7 @@
 package rawfile
 
 import (
+	"os"
 	"unsafe"
 
 	"golang.org/x/sys/unix"
@@ -105,7 +106,7 @@ func BlockingRead(fd int, b []byte) (int, tcpip.Error) {
 
 		event := PollEvent{
 			FD:     int32(fd),
-			Events: 1, // POLLIN
+			Events: unix.POLLIN,
 		}
 
 		_, e = BlockingPoll(&event, 1, nil)
@@ -119,21 +120,39 @@ func BlockingRead(fd int, b []byte) (int, tcpip.Error) {
 // stores the data in a list of iovecs buffers. If no data is available, it will
 // block in a poll() syscall until the file descriptor becomes readable.
 func BlockingReadv(fd int, iovecs []unix.Iovec) (int, tcpip.Error) {
+	return BlockingReadvWithCancel(fd, iovecs, nil)
+}
+
+func BlockingReadvWithCancel(fd int, iovecs []unix.Iovec, cancel *os.File) (int, tcpip.Error) {
 	for {
 		n, _, e := unix.RawSyscall(unix.SYS_READV, uintptr(fd), uintptr(unsafe.Pointer(&iovecs[0])), uintptr(len(iovecs)))
 		if e == 0 {
 			return int(n), nil
 		}
 
-		event := PollEvent{
-			FD:     int32(fd),
-			Events: 1, // POLLIN
+		var cancelFd uintptr = 0
+		nfds := 1
+
+		if cancel != nil {
+			cancelFd = cancel.Fd()
+			nfds += 1
 		}
 
-		_, e = BlockingPoll(&event, 1, nil)
+		events := []PollEvent{{
+			FD:     int32(fd),
+			Events: unix.POLLIN,
+		},{
+			FD:     int32(cancelFd),
+			Events: unix.POLLIN,
+		}}
+
+		_, e = BlockingPoll(&events[0], nfds, nil)
 		if e != 0 && e != unix.EINTR {
 			return 0, TranslateErrno(e)
 		}
+		if nfds > 1 && events[1].Revents == unix.POLLIN {
+			return 0, &tcpip.ErrAborted{}
+		}
 	}
 }
 
@@ -157,7 +176,7 @@ func BlockingRecvMMsg(fd int, msgHdrs []MMsgHdr) (int, tcpip.Error) {
 
 		event := PollEvent{
 			FD:     int32(fd),
-			Events: 1, // POLLIN
+			Events: unix.POLLIN,
 		}
 
 		if _, e := BlockingPoll(&event, 1, nil); e != 0 && e != unix.EINTR {