113 lines
2.4 KiB
Go
113 lines
2.4 KiB
Go
// Copyright 2019 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 flipcall
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import (
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"bytes"
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"fmt"
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"sync"
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)
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func Example() {
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const (
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reqPrefix = "request "
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respPrefix = "response "
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count = 3
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maxMessageLen = len(respPrefix) + 1 // 1 digit
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)
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pwa, err := NewPacketWindowAllocator()
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if err != nil {
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panic(err)
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}
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defer pwa.Destroy()
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pwd, err := pwa.Allocate(PacketWindowLengthForDataCap(uint32(maxMessageLen)))
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if err != nil {
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panic(err)
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}
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var clientEP Endpoint
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if err := clientEP.Init(ClientSide, pwd); err != nil {
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panic(err)
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}
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defer clientEP.Destroy()
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var serverEP Endpoint
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if err := serverEP.Init(ServerSide, pwd); err != nil {
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panic(err)
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}
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defer serverEP.Destroy()
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var serverRun sync.WaitGroup
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serverRun.Add(1)
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go func() {
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defer serverRun.Done()
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i := 0
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var buf bytes.Buffer
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// wait for first request
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n, err := serverEP.RecvFirst()
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if err != nil {
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return
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}
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for {
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// read request
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buf.Reset()
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buf.Write(serverEP.Data()[:n])
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fmt.Println(buf.String())
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// write response
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buf.Reset()
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fmt.Fprintf(&buf, "%s%d", respPrefix, i)
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copy(serverEP.Data(), buf.Bytes())
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// send response and wait for next request
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n, err = serverEP.SendRecv(uint32(buf.Len()))
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if err != nil {
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return
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}
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i++
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}
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}()
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defer func() {
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serverEP.Shutdown()
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serverRun.Wait()
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}()
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// establish connection as client
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if err := clientEP.Connect(); err != nil {
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panic(err)
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}
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var buf bytes.Buffer
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for i := 0; i < count; i++ {
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// write request
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buf.Reset()
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fmt.Fprintf(&buf, "%s%d", reqPrefix, i)
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copy(clientEP.Data(), buf.Bytes())
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// send request and wait for response
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n, err := clientEP.SendRecv(uint32(buf.Len()))
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if err != nil {
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panic(err)
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}
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// read response
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buf.Reset()
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buf.Write(clientEP.Data()[:n])
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fmt.Println(buf.String())
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}
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// Output:
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// request 0
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// response 0
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// request 1
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// response 1
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// request 2
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// response 2
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}
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