mirror of
https://github.com/impact-eintr/netstack.git
synced 2025-10-05 21:06:50 +08:00
78 lines
2.4 KiB
Go
78 lines
2.4 KiB
Go
package loopback
|
||
|
||
import (
|
||
"fmt"
|
||
"math/rand"
|
||
"netstack/logger"
|
||
"netstack/tcpip"
|
||
"netstack/tcpip/buffer"
|
||
"netstack/tcpip/stack"
|
||
"time"
|
||
)
|
||
|
||
type endpoint struct {
|
||
count int
|
||
dispatcher stack.NetworkDispatcher
|
||
}
|
||
|
||
func New() tcpip.LinkEndpointID {
|
||
return stack.RegisterLinkEndpoint(&endpoint{})
|
||
}
|
||
|
||
func (e *endpoint) MTU() uint32 {
|
||
return 65536
|
||
}
|
||
|
||
// Capabilities返回链路层端点支持的功能集。
|
||
func (e *endpoint) Capabilities() stack.LinkEndpointCapabilities {
|
||
return stack.CapabilityChecksumOffload | stack.CapabilitySaveRestore | stack.CapabilityLoopback
|
||
}
|
||
|
||
// MaxHeaderLength 返回数据链接（和较低级别的图层组合）标头可以具有的最大大小。
|
||
// 较高级别使用此信息来保留它们正在构建的数据包前面预留空间。
|
||
func (e *endpoint) MaxHeaderLength() uint16 {
|
||
return 0
|
||
}
|
||
|
||
// 本地链路层地址
|
||
func (e *endpoint) LinkAddress() tcpip.LinkAddress {
|
||
return ""
|
||
}
|
||
|
||
// 要参与透明桥接，LinkEndpoint实现应调用eth.Encode，
|
||
// 并将header.EthernetFields.SrcAddr设置为r.LocalLinkAddress（如果已提供）。
|
||
func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload buffer.VectorisedView,
|
||
protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
|
||
views := make([]buffer.View, 1, 1+len(payload.Views()))
|
||
views[0] = hdr.View()
|
||
views = append(views, payload.Views()...)
|
||
vv := buffer.NewVectorisedView(len(views[0])+payload.Size(), views)
|
||
|
||
// TODO 这里整点活 在特定的情况下丢掉数据报 模拟网络阻塞
|
||
rand.Seed(time.Now().Unix())
|
||
//time.Sleep(time.Duration(rand.Intn(50)+50) * time.Millisecond)
|
||
|
||
e.count++
|
||
if e.count == -1 { // 丢掉客户端写入的第二个包
|
||
logger.NOTICE(fmt.Sprintf("统计 %d 丢掉这个报文", e.count))
|
||
return nil
|
||
}
|
||
// Because we're immediately turning around and writing the packet back to the
|
||
// rx path, we intentionally don't preserve the remote and local link
|
||
// addresses from the stack.Route we're passed.
|
||
//logger.NOTICE(fmt.Sprintf("统计分发 %d 报文", e.count))
|
||
e.dispatcher.DeliverNetworkPacket(e, "" /* remoteLinkAddr */, "" /* localLinkAddr */, protocol, vv)
|
||
|
||
return nil
|
||
}
|
||
|
||
// Attach 将数据链路层端点附加到协议栈的网络层调度程序。
|
||
func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
|
||
e.dispatcher = dispatcher
|
||
}
|
||
|
||
// 是否已经添加了网络层调度器
|
||
func (e *endpoint) IsAttached() bool {
|
||
return e.dispatcher != nil
|
||
}
|