diff --git a/pkg/sentry/socket/unix/transport/queue.go b/pkg/sentry/socket/unix/transport/queue.go index 5dcd3d95e..d8f3ad63d 100644 --- a/pkg/sentry/socket/unix/transport/queue.go +++ b/pkg/sentry/socket/unix/transport/queue.go @@ -18,6 +18,8 @@ import ( "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserr" + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/waiter" ) @@ -100,12 +102,16 @@ func (q *queue) IsWritable() bool { // Enqueue adds an entry to the data queue if room is available. // +// If discardEmpty is true and there are zero bytes of data, the packet is +// dropped. +// // If truncate is true, Enqueue may truncate the message before enqueuing it. -// Otherwise, the entire message must fit. If n < e.Length(), err indicates why. +// Otherwise, the entire message must fit. If l is less than the size of data, +// err indicates why. // // If notify is true, ReaderQueue.Notify must be called: // q.ReaderQueue.Notify(waiter.EventIn) -func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *syserr.Error) { +func (q *queue) Enqueue(data [][]byte, c ControlMessages, from tcpip.FullAddress, discardEmpty bool, truncate bool) (l int64, notify bool, err *syserr.Error) { q.mu.Lock() if q.closed { @@ -113,9 +119,16 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s return 0, false, syserr.ErrClosedForSend } - free := q.limit - q.used + for _, d := range data { + l += int64(len(d)) + } + if discardEmpty && l == 0 { + q.mu.Unlock() + c.Release() + return 0, false, nil + } - l = e.Length() + free := q.limit - q.used if l > free && truncate { if free == 0 { @@ -124,8 +137,7 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s return 0, false, syserr.ErrWouldBlock } - e.Truncate(free) - l = e.Length() + l = free err = syserr.ErrWouldBlock } @@ -136,14 +148,26 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s } if l > free { - // Message can't fit right now. + // Message can't fit right now, and could not be truncated. q.mu.Unlock() return 0, false, syserr.ErrWouldBlock } + // Aggregate l bytes of data. This will truncate the data if l is less than + // the total bytes held in data. + v := make([]byte, l) + for i, b := 0, v; i < len(data) && len(b) > 0; i++ { + n := copy(b, data[i]) + b = b[n:] + } + notify = q.dataList.Front() == nil q.used += l - q.dataList.PushBack(e) + q.dataList.PushBack(&message{ + Data: buffer.View(v), + Control: c, + Address: from, + }) q.mu.Unlock() diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go index dcbafe0e5..2ef654235 100644 --- a/pkg/sentry/socket/unix/transport/unix.go +++ b/pkg/sentry/socket/unix/transport/unix.go @@ -581,7 +581,7 @@ type ConnectedEndpoint interface { // // syserr.ErrWouldBlock can be returned along with a partial write if // the caller should block to send the rest of the data. - Send(data [][]byte, controlMessages ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error) + Send(data [][]byte, c ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error) // SendNotify notifies the ConnectedEndpoint of a successful Send. This // must not be called while holding any endpoint locks. @@ -653,35 +653,22 @@ func (e *connectedEndpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) } // Send implements ConnectedEndpoint.Send. -func (e *connectedEndpoint) Send(data [][]byte, controlMessages ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { - var l int64 - for _, d := range data { - l += int64(len(d)) - } - +func (e *connectedEndpoint) Send(data [][]byte, c ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { + discardEmpty := false truncate := false if e.endpoint.Type() == linux.SOCK_STREAM { - // Since stream sockets don't preserve message boundaries, we - // can write only as much of the message as fits in the queue. - truncate = true - // Discard empty stream packets. Since stream sockets don't // preserve message boundaries, sending zero bytes is a no-op. // In Linux, the receiver actually uses a zero-length receive // as an indication that the stream was closed. - if l == 0 { - controlMessages.Release() - return 0, false, nil - } + discardEmpty = true + + // Since stream sockets don't preserve message boundaries, we + // can write only as much of the message as fits in the queue. + truncate = true } - v := make([]byte, 0, l) - for _, d := range data { - v = append(v, d...) - } - - l, notify, err := e.writeQueue.Enqueue(&message{Data: buffer.View(v), Control: controlMessages, Address: from}, truncate) - return int64(l), notify, err + return e.writeQueue.Enqueue(data, c, from, discardEmpty, truncate) } // SendNotify implements ConnectedEndpoint.SendNotify.