使用F＃中的原始套接字编写异步Ping，以使用尽可能少的线程启用并行请求。不使用“System.Net.NetworkInformation.Ping”，因为它似乎为每个请求分配一个线程。我也对使用F＃异步工作流感兴趣。
当目标主机不存在/响应时，下面的同步版本会正确超时，但异步版本会挂起。当主机做出响应时，两者都有效。不确定这是一个.NET问题，还是一个F＃...
有什么想法吗？
（注意：该进程必须以Admin身份运行以允许Raw Socket访问）
这会引发超时：
let result = Ping.Ping ( IPAddress.Parse( "192.168.33.22" ), 1000 )
然而，这种情况仍然存在：
let result = Ping.AsyncPing ( IPAddress.Parse( "192.168.33.22" ), 1000 )
|> Async.RunSynchronously
这是代码......
module Ping
open System
open System.Net
open System.Net.Sockets
open System.Threading
//---- ICMP Packet Classes
type IcmpMessage (t : byte) =
let mutable m_type = t
let mutable m_code = 0uy
let mutable m_checksum = 0us
member this.Type
with get() = m_type
member this.Code
with get() = m_code
member this.Checksum = m_checksum
abstract Bytes : byte array
default this.Bytes
with get() =
[|
m_type
m_code
byte(m_checksum)
byte(m_checksum >>> 8)
|]
member this.GetChecksum() =
let mutable sum = 0ul
let bytes = this.Bytes
let mutable i = 0
// Sum up uint16s
while i < bytes.Length - 1 do
sum <- sum + uint32(BitConverter.ToUInt16( bytes, i ))
i <- i + 2
// Add in last byte, if an odd size buffer
if i <> bytes.Length then
sum <- sum + uint32(bytes.[i])
// Shuffle the bits
sum <- (sum >>> 16) + (sum &&& 0xFFFFul)
sum <- sum + (sum >>> 16)
sum <- ~~~sum
uint16(sum)
member this.UpdateChecksum() =
m_checksum <- this.GetChecksum()
type InformationMessage (t : byte) =
inherit IcmpMessage(t)
let mutable m_identifier = 0us
let mutable m_sequenceNumber = 0us
member this.Identifier = m_identifier
member this.SequenceNumber = m_sequenceNumber
override this.Bytes
with get() =
Array.append (base.Bytes)
[|
byte(m_identifier)
byte(m_identifier >>> 8)
byte(m_sequenceNumber)
byte(m_sequenceNumber >>> 8)
|]
type EchoMessage() =
inherit InformationMessage( 8uy )
let mutable m_data = Array.create 32 32uy
do base.UpdateChecksum()
member this.Data
with get() = m_data
and set(d) = m_data <- d
this.UpdateChecksum()
override this.Bytes
with get() =
Array.append (base.Bytes)
(this.Data)
//---- Synchronous Ping
let Ping (host : IPAddress, timeout : int ) =
let mutable ep = new IPEndPoint( host, 0 )
let socket = new Socket( AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp )
socket.SetSocketOption( SocketOptionLevel.Socket, SocketOptionName.SendTimeout, timeout )
socket.SetSocketOption( SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, timeout )
let packet = EchoMessage()
let mutable buffer = packet.Bytes
try
if socket.SendTo( buffer, ep ) <= 0 then
raise (SocketException())
buffer <- Array.create (buffer.Length + 20) 0uy
let mutable epr = ep :> EndPoint
if socket.ReceiveFrom( buffer, &epr ) <= 0 then
raise (SocketException())
finally
socket.Close()
buffer
//---- Entensions to the F# Async class to allow up to 5 paramters (not just 3)
type Async with
static member FromBeginEnd(arg1,arg2,arg3,arg4,beginAction,endAction,?cancelAction): Async<'T> =
Async.FromBeginEnd((fun (iar,state) -> beginAction(arg1,arg2,arg3,arg4,iar,state)), endAction, ?cancelAction=cancelAction)
static member FromBeginEnd(arg1,arg2,arg3,arg4,arg5,beginAction,endAction,?cancelAction): Async<'T> =
Async.FromBeginEnd((fun (iar,state) -> beginAction(arg1,arg2,arg3,arg4,arg5,iar,state)), endAction, ?cancelAction=cancelAction)
//---- Extensions to the Socket class to provide async SendTo and ReceiveFrom
type System.Net.Sockets.Socket with
member this.AsyncSendTo( buffer, offset, size, socketFlags, remoteEP ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, remoteEP,
this.BeginSendTo,
this.EndSendTo )
member this.AsyncReceiveFrom( buffer, offset, size, socketFlags, remoteEP ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, remoteEP,
this.BeginReceiveFrom,
(fun asyncResult -> this.EndReceiveFrom(asyncResult, remoteEP) ) )
//---- Asynchronous Ping
let AsyncPing (host : IPAddress, timeout : int ) =
async {
let ep = IPEndPoint( host, 0 )
use socket = new Socket( AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp )
socket.SetSocketOption( SocketOptionLevel.Socket, SocketOptionName.SendTimeout, timeout )
socket.SetSocketOption( SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, timeout )
let packet = EchoMessage()
let outbuffer = packet.Bytes
try
let! result = socket.AsyncSendTo( outbuffer, 0, outbuffer.Length, SocketFlags.None, ep )
if result <= 0 then
raise (SocketException())
let epr = ref (ep :> EndPoint)
let inbuffer = Array.create (outbuffer.Length + 256) 0uy
let! result = socket.AsyncReceiveFrom( inbuffer, 0, inbuffer.Length, SocketFlags.None, epr )
if result <= 0 then
raise (SocketException())
return inbuffer
finally
socket.Close()
}
答案 0 :(得分：7)
詹姆斯，你自己接受的答案有一个我想指出的问题。您只分配一个计时器，这使AsyncReceiveEx返回的异步对象成为有状态的一次性对象。这是我剪下来的一个类似的例子：
let b,e,c = Async.AsBeginEnd(Async.Sleep)
type Example() =
member this.Close() = ()
member this.AsyncReceiveEx( sleepTime, (timeoutMS:int) ) =
let timedOut = ref false
let completed = ref false
let timer = new System.Timers.Timer(double(timeoutMS), AutoReset=false)
timer.Elapsed.Add( fun _ ->
lock timedOut (fun () ->
timedOut := true
if not !completed
then this.Close()
)
)
let complete() =
lock timedOut (fun () ->
timer.Stop()
timer.Dispose()
completed := true
)
Async.FromBeginEnd( sleepTime,
(fun st ->
let result = b(st)
timer.Start()
result
),
(fun result ->
complete()
if !timedOut
then printfn "err"; ()
else e(result)
),
(fun () ->
complete()
this.Close()
)
)
let ex = new Example()
let a = ex.AsyncReceiveEx(3000, 1000)
Async.RunSynchronously a
printfn "ok..."
// below throws ODE, because only allocated one Timer
Async.RunSynchronously a
理想情况下，您希望AsyncReceiveEx返回的异步的每次“运行”行为相同，这意味着每次运行都需要自己的计时器和一组ref标志。这很容易解决：
let b,e,c = Async.AsBeginEnd(Async.Sleep)
type Example() =
member this.Close() = ()
member this.AsyncReceiveEx( sleepTime, (timeoutMS:int) ) =
async {
let timedOut = ref false
let completed = ref false
let timer = new System.Timers.Timer(double(timeoutMS), AutoReset=false)
timer.Elapsed.Add( fun _ ->
lock timedOut (fun () ->
timedOut := true
if not !completed
then this.Close()
)
)
let complete() =
lock timedOut (fun () ->
timer.Stop()
timer.Dispose()
completed := true
)
return! Async.FromBeginEnd( sleepTime,
(fun st ->
let result = b(st)
timer.Start()
result
),
(fun result ->
complete()
if !timedOut
then printfn "err"; ()
else e(result)
),
(fun () ->
complete()
this.Close()
)
)
}
let ex = new Example()
let a = ex.AsyncReceiveEx(3000, 1000)
Async.RunSynchronously a
printfn "ok..."
Async.RunSynchronously a
唯一的变化是将AsyncReceiveEx的主体放在async{...}内，并且最后一行return!。
答案 1 :(得分：3)
答案 2 :(得分：2)
经过一番思考，想出了以下内容。此代码将AsyncReceiveEx成员添加到Socket，其中包含超时值。它隐藏了接收方法中看门狗定时器的细节......非常整洁和自包含。现在这就是我要找的东西！
请参阅下面的完整异步ping示例。
不确定锁是否必要，但比抱歉更安全......
type System.Net.Sockets.Socket with
member this.AsyncSend( buffer, offset, size, socketFlags, err ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
this.BeginSend,
this.EndSend,
this.Close )
member this.AsyncReceive( buffer, offset, size, socketFlags, err ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
this.BeginReceive,
this.EndReceive,
this.Close )
member this.AsyncReceiveEx( buffer, offset, size, socketFlags, err, (timeoutMS:int) ) =
async {
let timedOut = ref false
let completed = ref false
let timer = new System.Timers.Timer( double(timeoutMS), AutoReset=false )
timer.Elapsed.Add( fun _ ->
lock timedOut (fun () ->
timedOut := true
if not !completed
then this.Close()
)
)
let complete() =
lock timedOut (fun () ->
timer.Stop()
timer.Dispose()
completed := true
)
return! Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
(fun (b,o,s,sf,e,st,uo) ->
let result = this.BeginReceive(b,o,s,sf,e,st,uo)
timer.Start()
result
),
(fun result ->
complete()
if !timedOut
then err := SocketError.TimedOut; 0
else this.EndReceive( result, err )
),
(fun () ->
complete()
this.Close()
)
)
}
这是一个完整的Ping示例。为了避免耗尽源端口并防止一次收到太多回复，它一次扫描一个C类子网。
module Ping
open System
open System.Net
open System.Net.Sockets
open System.Threading
//---- ICMP Packet Classes
type IcmpMessage (t : byte) =
let mutable m_type = t
let mutable m_code = 0uy
let mutable m_checksum = 0us
member this.Type
with get() = m_type
member this.Code
with get() = m_code
member this.Checksum = m_checksum
abstract Bytes : byte array
default this.Bytes
with get() =
[|
m_type
m_code
byte(m_checksum)
byte(m_checksum >>> 8)
|]
member this.GetChecksum() =
let mutable sum = 0ul
let bytes = this.Bytes
let mutable i = 0
// Sum up uint16s
while i < bytes.Length - 1 do
sum <- sum + uint32(BitConverter.ToUInt16( bytes, i ))
i <- i + 2
// Add in last byte, if an odd size buffer
if i <> bytes.Length then
sum <- sum + uint32(bytes.[i])
// Shuffle the bits
sum <- (sum >>> 16) + (sum &&& 0xFFFFul)
sum <- sum + (sum >>> 16)
sum <- ~~~sum
uint16(sum)
member this.UpdateChecksum() =
m_checksum <- this.GetChecksum()
type InformationMessage (t : byte) =
inherit IcmpMessage(t)
let mutable m_identifier = 0us
let mutable m_sequenceNumber = 0us
member this.Identifier = m_identifier
member this.SequenceNumber = m_sequenceNumber
override this.Bytes
with get() =
Array.append (base.Bytes)
[|
byte(m_identifier)
byte(m_identifier >>> 8)
byte(m_sequenceNumber)
byte(m_sequenceNumber >>> 8)
|]
type EchoMessage() =
inherit InformationMessage( 8uy )
let mutable m_data = Array.create 32 32uy
do base.UpdateChecksum()
member this.Data
with get() = m_data
and set(d) = m_data <- d
this.UpdateChecksum()
override this.Bytes
with get() =
Array.append (base.Bytes)
(this.Data)
//---- Entensions to the F# Async class to allow up to 5 paramters (not just 3)
type Async with
static member FromBeginEnd(arg1,arg2,arg3,arg4,beginAction,endAction,?cancelAction): Async<'T> =
Async.FromBeginEnd((fun (iar,state) -> beginAction(arg1,arg2,arg3,arg4,iar,state)), endAction, ?cancelAction=cancelAction)
static member FromBeginEnd(arg1,arg2,arg3,arg4,arg5,beginAction,endAction,?cancelAction): Async<'T> =
Async.FromBeginEnd((fun (iar,state) -> beginAction(arg1,arg2,arg3,arg4,arg5,iar,state)), endAction, ?cancelAction=cancelAction)
//---- Extensions to the Socket class to provide async SendTo and ReceiveFrom
type System.Net.Sockets.Socket with
member this.AsyncSend( buffer, offset, size, socketFlags, err ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
this.BeginSend,
this.EndSend,
this.Close )
member this.AsyncReceive( buffer, offset, size, socketFlags, err ) =
Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
this.BeginReceive,
this.EndReceive,
this.Close )
member this.AsyncReceiveEx( buffer, offset, size, socketFlags, err, (timeoutMS:int) ) =
async {
let timedOut = ref false
let completed = ref false
let timer = new System.Timers.Timer( double(timeoutMS), AutoReset=false )
timer.Elapsed.Add( fun _ ->
lock timedOut (fun () ->
timedOut := true
if not !completed
then this.Close()
)
)
let complete() =
lock timedOut (fun () ->
timer.Stop()
timer.Dispose()
completed := true
)
return! Async.FromBeginEnd( buffer, offset, size, socketFlags, err,
(fun (b,o,s,sf,e,st,uo) ->
let result = this.BeginReceive(b,o,s,sf,e,st,uo)
timer.Start()
result
),
(fun result ->
complete()
if !timedOut
then err := SocketError.TimedOut; 0
else this.EndReceive( result, err )
),
(fun () ->
complete()
this.Close()
)
)
}
//---- Asynchronous Ping
let AsyncPing (ip : IPAddress, timeout : int ) =
async {
use socket = new Socket( AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp )
socket.Connect( IPEndPoint( ip, 0 ) )
let pingTime = System.Diagnostics.Stopwatch()
let packet = EchoMessage()
let outbuffer = packet.Bytes
let err = ref (SocketError())
let isAlive = ref false
try
pingTime.Start()
let! result = socket.AsyncSend( outbuffer, 0, outbuffer.Length, SocketFlags.None, err )
pingTime.Stop()
if result <= 0 then
raise (SocketException(int(!err)))
let inbuffer = Array.create (outbuffer.Length + 256) 0uy
pingTime.Start()
let! reply = socket.AsyncReceiveEx( inbuffer, 0, inbuffer.Length, SocketFlags.None, err, timeout )
pingTime.Stop()
if result <= 0 && not (!err = SocketError.TimedOut) then
raise (SocketException(int(!err)))
isAlive := not (!err = SocketError.TimedOut)
&& inbuffer.[25] = 0uy // Type 0 = echo reply (redundent? necessary?)
&& inbuffer.[26] = 0uy // Code 0 = echo reply (redundent? necessary?)
finally
socket.Close()
return (ip, pingTime.Elapsed, !isAlive )
}
let main() =
let pings net =
seq {
for node in 0..255 do
let ip = IPAddress.Parse( sprintf "192.168.%d.%d" net node )
yield Ping.AsyncPing( ip, 1000 )
}
for net in 0..255 do
pings net
|> Async.Parallel
|> Async.RunSynchronously
|> Seq.filter ( fun (_,_,alive) -> alive )
|> Seq.iter ( fun (ip, time, alive) ->
printfn "%A %dms" ip time.Milliseconds)
main()
System.Console.ReadKey() |> ignore
答案 3 :(得分：1)
有几件事......
首先，可以将.NET FooAsync / FooCompleted模式调整为F＃异步。 FSharp.Core库为WebClient执行此操作;我想你可以在这里使用相同的模式。这是WebClient代码
type System.Net.WebClient with
member this.AsyncDownloadString (address:Uri) : Async<string> =
let downloadAsync =
Async.FromContinuations (fun (cont, econt, ccont) ->
let userToken = new obj()
let rec handler =
System.Net.DownloadStringCompletedEventHandler (fun _ args ->
if userToken = args.UserState then
this.DownloadStringCompleted.RemoveHandler(handler)
if args.Cancelled then
ccont (new OperationCanceledException())
elif args.Error <> null then
econt args.Error
else
cont args.Result)
this.DownloadStringCompleted.AddHandler(handler)
this.DownloadStringAsync(address, userToken)
)
async {
use! _holder = Async.OnCancel(fun _ -> this.CancelAsync())
return! downloadAsync
}
我认为您可以对SendAsync / SendAsyncCancel / PingCompleted执行相同操作（我没有仔细考虑过）。
其次，为方法AsyncPing命名，而不是PingAsync。 F＃异步方法名为AsyncFoo，而具有事件模式的方法名为FooAsync。
我没有仔细查看您的代码，试图找出错误所在的位置。
答案 4 :(得分：0)
这是使用Async.FromContinuations的版本。
然而，这不是我的问题的答案，因为它不能扩展。该代码可能对某人有用，因此请在此处发布。
这不是答案的原因是因为System.Net.NetworkInformation.Ping似乎每个Ping使用一个线程和相当多的内存（可能是由于线程堆栈空间）。尝试ping整个B类网络将耗尽内存并使用100个线程，而使用原始套接字的代码仅使用少量线程且低于10Mb。
type System.Net.NetworkInformation.Ping with
member this.AsyncPing (address:IPAddress) : Async<PingReply> =
let pingAsync =
Async.FromContinuations (fun (cont, econt, ccont) ->
let userToken = new obj()
let rec handler =
PingCompletedEventHandler (fun _ args ->
if userToken = args.UserState then
this.PingCompleted.RemoveHandler(handler)
if args.Cancelled then
ccont (new OperationCanceledException())
elif args.Error <> null then
econt args.Error
else
cont args.Reply)
this.PingCompleted.AddHandler(handler)
this.SendAsync(address, 1000, userToken)
)
async {
use! _holder = Async.OnCancel(fun _ -> this.SendAsyncCancel())
return! pingAsync
}
let AsyncPingTest() =
let pings =
seq {
for net in 0..255 do
for node in 0..255 do
let ip = IPAddress.Parse( sprintf "192.168.%d.%d" net node )
let ping = new Ping()
yield ping.AsyncPing( ip )
}
pings
|> Async.Parallel
|> Async.RunSynchronously
|> Seq.iter ( fun result ->
printfn "%A" result )
答案 5 :(得分：0)
编辑代码已更改为正常工作版。
James，我修改了你的代码，它看起来和你的版本一样好，但是使用MailboxProcessor作为超时处理程序引擎。该代码比您的版本慢4倍，但使用的内存减少了1.5倍。
let AsyncPing (host: IPAddress) timeout =
let guard =
MailboxProcessor<AsyncReplyChannel<Socket*byte array>>.Start(
fun inbox ->
async {
try
let socket = new Socket( AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp )
try
let ep = IPEndPoint( host, 0 )
let packet = EchoMessage()
let outbuffer = packet.Bytes
let! reply = inbox.Receive()
let! result = socket.AsyncSendTo( outbuffer, 0, outbuffer.Length, SocketFlags.None, ep )
if result <= 0 then
raise (SocketException())
let epr = ref (ep :> EndPoint)
let inbuffer = Array.create (outbuffer.Length + 256) 0uy
let! result = socket.AsyncReceiveFrom( inbuffer, 0, inbuffer.Length, SocketFlags.None, epr )
if result <= 0 then
raise (SocketException())
reply.Reply(socket,inbuffer)
return ()
finally
socket.Close()
finally
()
})
async {
try
//#1: blocks thread and as result have large memory footprint and too many threads to use
//let socket,r = guard.PostAndReply(id,timeout=timeout)
//#2: suggested by Dmitry Lomov
let! socket,r = guard.PostAndAsyncReply(id,timeout=timeout)
printfn "%A: ok" host
socket.Close()
with
_ ->
printfn "%A: failed" host
()
}
//test it
//timeout is ms interval
//i.e. 10000 is equal to 10s
let AsyncPingTest timeout =
seq {
for net in 1..254 do
for node in 1..254 do
let ip = IPAddress.Parse( sprintf "192.168.%d.%d" net node )
yield AsyncPing ip timeout
}
|> Async.Parallel
|> Async.RunSynchronously
答案 6 :(得分：0)