81 lines
2.8 KiB
Go
81 lines
2.8 KiB
Go
// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package tcp_rcv_buf_space_test
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import (
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"context"
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"flag"
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"syscall"
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"testing"
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"golang.org/x/sys/unix"
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"gvisor.dev/gvisor/pkg/tcpip/header"
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"gvisor.dev/gvisor/test/packetimpact/testbench"
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)
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func init() {
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testbench.RegisterFlags(flag.CommandLine)
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}
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// TestReduceRecvBuf tests that a packet within window is still dropped
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// if the available buffer space drops below the size of the incoming
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// segment.
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func TestReduceRecvBuf(t *testing.T) {
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dut := testbench.NewDUT(t)
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defer dut.TearDown()
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listenFd, remotePort := dut.CreateListener(t, unix.SOCK_STREAM, unix.IPPROTO_TCP, 1)
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defer dut.Close(t, listenFd)
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conn := testbench.NewTCPIPv4(t, testbench.TCP{DstPort: &remotePort}, testbench.TCP{SrcPort: &remotePort})
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defer conn.Close(t)
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conn.Connect(t)
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acceptFd, _ := dut.Accept(t, listenFd)
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defer dut.Close(t, acceptFd)
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// Set a small receive buffer for the test.
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const rcvBufSz = 4096
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dut.SetSockOptInt(t, acceptFd, unix.SOL_SOCKET, unix.SO_RCVBUF, rcvBufSz)
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// Retrieve the actual buffer.
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bufSz := dut.GetSockOptInt(t, acceptFd, unix.SOL_SOCKET, unix.SO_RCVBUF)
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// Generate a payload of 1 more than the actual buffer size used by the
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// DUT.
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sampleData := testbench.GenerateRandomPayload(t, int(bufSz)+1)
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// Send and receive sample data to the dut.
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const pktSize = 1400
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for payload := sampleData; len(payload) != 0; {
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payloadBytes := pktSize
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if l := len(payload); l < payloadBytes {
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payloadBytes = l
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}
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conn.Send(t, testbench.TCP{Flags: testbench.Uint8(header.TCPFlagAck)}, []testbench.Layer{&testbench.Payload{Bytes: payload[:payloadBytes]}}...)
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payload = payload[payloadBytes:]
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}
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// First read should read < len(sampleData)
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if ret, _, err := dut.RecvWithErrno(context.Background(), t, acceptFd, int32(len(sampleData)), 0); ret == -1 || int(ret) == len(sampleData) {
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t.Fatalf("dut.RecvWithErrno(ctx, t, %d, %d, 0) = %d,_, %s", acceptFd, int32(len(sampleData)), ret, err)
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}
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// Second read should return EAGAIN as the last segment should have been
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// dropped due to it exceeding the receive buffer space available in the
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// socket.
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if ret, got, err := dut.RecvWithErrno(context.Background(), t, acceptFd, int32(len(sampleData)), syscall.MSG_DONTWAIT); got != nil || ret != -1 || err != syscall.EAGAIN {
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t.Fatalf("expected no packets but got: %s", got)
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}
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}
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