<div dir="ltr">Great, I just had a go with your changes and it now works for me. There are a couple of typos, you don't pass in the max-buffer-size keyword arg and you forgot to rename my variable from "usocket" to "socket" (diff attached). <div><br></div><div>With those changes I think I'm happy. Thanks again for looking into this for me.</div><div>Frank,</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 27 May 2015 at 19:09, Chun Tian (binghe) <span dir="ltr"><<a href="mailto:binghe.lisp@gmail.com" target="_blank">binghe.lisp@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Frank,<br>
<br>
Thank you very much! Now I understand the issue, and I think your patch is correct. The function RECEIVE-MESSAGE was directly from my early work (the LispWorks-UDP [1] package), in which there’s no WAIT-FOR-INPUT yet, and raw socket fd is the user-level socket object. If RECEIVE-MESSAGE starts to touch the other slots in the usocket object, we should move all its code back to the SOCKET-RECEIVE method.<br>
<br>
Any way, I have committed a fix with your idea to latest Github master [2], but when I ran your test code, I get following results in both Windows and Mac:<br>
<span class=""><br>
0s 0 Waiting state NIL<br>
</span>5s 1 Waiting state NIL<br>
10s 2 Waiting state NIL<br>
15s 3 Waiting state NIL<br>
<br>
I think that’s because WAIT-FOR-INPUT always returns NIL (nothing can be read from the UDP server socket), therefore your other code (using SOCKET-RECEIVE and SOCKET-SEND) never get a chance to be called… do you think this is reasonable?<br>
<br>
Regards,<br>
<br>
Chun<br>
<br>
[1] <a href="https://common-lisp.net/project/cl-net-snmp/lispworks.html" target="_blank">https://common-lisp.net/project/cl-net-snmp/lispworks.html</a><br>
[2] <a href="https://github.com/usocket/usocket/commit/8763542e354af85989678188898af57e50fc0fbb" target="_blank">https://github.com/usocket/usocket/commit/8763542e354af85989678188898af57e50fc0fbb</a><br>
<div><div class="h5"><br>
Il giorno 26/mag/2015, alle ore 17:30, Frank James <<a href="mailto:frank.a.james@gmail.com">frank.a.james@gmail.com</a>> ha scritto:<br>
<br>
> Hi Chun,<br>
><br>
> I've had a bit more time to look into this and I think I've got a better idea of what's going on.<br>
><br>
> Firstly, I had a really obvious typo above (doh!) which caused the error I saw in socket-send (2, above). Putting in the count parameter and the socket-send succeeds, as expected.<br>
><br>
> Replacing the handler-case with handler-bind and dropping into the debugger, I identified where the strange error I was seeing with socket-receive comes from (4, above). It seems the recvfrom is returning an error code of 10035, (WSAEWOULDBLOCK), which you are signalling with a condition. But the ns-try-again-condition only has a :HOST-OR-IP initarg, not a :SOCKET initarg. So I commented out that bit of code and the condition is signalled ok (although I'm not handling it, but that's fine).<br>
><br>
> So my test function is<br>
><br>
> (defun usocket-test ()<br>
> (let ((s (usocket:socket-connect nil nil<br>
> :protocol :datagram<br>
> :element-type '(unsigned-byte 8)<br>
> :local-port 8001)))<br>
> (unwind-protect<br>
> (do ((i 0 (1+ i))<br>
> (buffer (make-array 1024 :element-type '(unsigned-byte 8)<br>
> :initial-element 0))<br>
> (now (get-universal-time))<br>
> (done nil))<br>
> ((or done (= i 4))<br>
> nil)<br>
> (format t "~Ds ~D Waiting state ~S~%" (- (get-universal-time) now) i (usocket::state s))<br>
> (when (usocket:wait-for-input s :ready-only t :timeout 5)<br>
> (format t "~D state ~S~%" i (usocket::state s))<br>
> (handler-bind<br>
> ((error (lambda (c)<br>
> (format t "socket-receive error: ~A~%" c)<br>
> (break)<br>
> nil)))<br>
> (multiple-value-bind (buffer count remote-host remote-port)<br>
><br>
> (usocket:socket-receive s buffer 1024)<br>
> (handler-bind<br>
> ((error (lambda (c)<br>
> (format t "socket-send error: ~A~%" c)<br>
> (break))))<br>
> (when buffer<br>
> (usocket:socket-send s (subseq buffer 0 count) count<br>
> :host remote-host<br>
> :port remote-port)))))))<br>
> (usocket:socket-close s))))<br>
><br>
><br>
><br>
> My output is now:<br>
><br>
> 0s 0 Waiting state NIL<br>
> 0 state :READ<br>
> 2s 1 Waiting state :READ<br>
> 1 state :READ<br>
> 2s 2 Waiting state :READ<br>
> 2 state :READ<br>
> 2s 3 Waiting state :READ<br>
> 3 state :READ<br>
> NIL<br>
><br>
><br>
> We are getting closer. The read state is still staying in :READ even after a successful socket-receive call, so the loop is still spinning. I can fix this easily by passing in the socket instance directly to the receive-message function and manually setting the %ready-p flag to nil. This gives me the correct behaviour:<br>
><br>
> 0s 0 Waiting state NIL<br>
> 0 state :READ<br>
> 4s 1 Waiting state :READ<br>
> 9s 2 Waiting state NIL<br>
> 14s 3 Waiting state NIL<br>
> NIL<br>
><br>
> I've attached a diff of backend/lispworks.lisp showing what I describe above, feel free to use/ignore it.<br>
><br>
><br>
> Frank.<br>
><br>
><br>
><br>
> On 24 May 2015 at 20:57, Frank James <<a href="mailto:frank.a.james@gmail.com">frank.a.james@gmail.com</a>> wrote:<br>
> Hi Chun,<br>
><br>
> Thanks for looking into this. I've just pulled the most recent codes from github and have had a little play with them. I now get an error signalled on the socket-receive when I expect an error (rather than a simple -1 count as before). This is good.<br>
><br>
> However, I am still seeing the socket-state behaviour I described before, along with a new bug that has probably been introduced by the recent changes.<br>
><br>
> Consider the following simple function which listens for UDP port 8001 for up to 4 iterations:<br>
><br>
> (defun usocket-test ()<br>
> (let ((s (usocket:socket-connect nil nil<br>
> :protocol :datagram<br>
> :element-type '(unsigned-byte 8)<br>
> :local-port 8001)))<br>
> (unwind-protect<br>
> (do ((i 0 (1+ i))<br>
> (buffer (make-array 1024 :element-type '(unsigned-byte 8) :initial-element 0))<br>
> (done nil))<br>
> ((or done (= i 4))<br>
> nil)<br>
> (when (usocket:wait-for-input s :ready-only t :timeout 10)<br>
> (format t "~D state ~S~%" i (usocket::state s))<br>
> (handler-case<br>
> (multiple-value-bind (buffer count remote-host remote-port)<br>
> (usocket:socket-receive s buffer 1024)<br>
> (handler-case<br>
> (usocket:socket-send s (subseq buffer 0 count)<br>
> :host remote-host<br>
> :port remote-port)<br>
> (error (c)<br>
> (format t "socket-send error: ~A~%" c))))<br>
> (error (c)<br>
> (format t "socket-receive error: ~A~%" c)))))<br>
> (usocket:socket-close s))))<br>
><br>
><br>
> after calling this from your repl, from another process send a UDP packet to port 8001 to get things going. I get the following output:<br>
><br>
> 0 state :READ<br>
> socket-send error: #<STANDARD-GENERIC-FUNCTION USOCKET:SOCKET-SEND 21CADCFA> is called with unpaired keyword in (2130706433 :PORT 58279).<br>
> 1 state :READ<br>
> socket-receive error: MAKE-INSTANCE is called with keyword :SOCKET among the arguments (USOCKET:NS-TRY-AGAIN-CONDITION :SOCKET 2604) which is not one of (:HOST-OR-IP).<br>
> 2 state :READ<br>
> socket-receive error: MAKE-INSTANCE is called with keyword :SOCKET among the arguments (USOCKET:NS-TRY-AGAIN-CONDITION :SOCKET 2604) which is not one of (:HOST-OR-IP).<br>
> 3 state :READ<br>
> socket-receive error: MAKE-INSTANCE is called with keyword :SOCKET among the arguments (USOCKET:NS-TRY-AGAIN-CONDITION :SOCKET 2604) which is not one of (:HOST-OR-IP).<br>
> NIL<br>
><br>
> My observations:<br>
> 1. The initial socket-receive succeeds (as expected).<br>
> 2. The initial socket-send fails with an error I've not seen before and can't diagnose...<br>
> 3. Subsequent calls to wait-for-input return immediately because the socket is still in a :READ state, even though I already successfully called socket-receive in the first iteration.<br>
> 4. Subsequent calls to socket-receive now fail with a different error I can't diagnose.<br>
><br>
> If I didn't have the max iteration cap, this would spin using 100% of a CPU core and adding around 2MB to the heap per second (on my machine), maxing out the 1GB personal edition heap limit in a short space of time. So I think it's a pretty serious issue. I mainly use SBCL, I use LispWorks occasionally to make sure my codes work on at least 1 other implementation, so I'm not exactly a LispWorks expert.<br>
><br>
> If you want any more explanations, clarifications or examples I'll be happy to do my best to help.<br>
><br>
> As before, I'm using LispWorks personal edition 6.1.1 on Windows 8.1.<br>
><br>
> Frank.<br>
><br>
><br>
><br>
> On 22 May 2015 at 09:24, Chun Tian (binghe) <<a href="mailto:binghe.lisp@gmail.com">binghe.lisp@gmail.com</a>> wrote:<br>
> Hi Frank,<br>
><br>
> Today I have modified SOCKET-SEND and SOCKET-RECEIVE for LispWorks, to be able to detect and report socket errors. I think in this way, these APIs on LispWorks could behavior closer to other platforms.<br>
><br>
> Now on Windows, your test code should return a USOCKET:CONNECTION-RESET-ERROR condition, which equals to WSA error ECONNRESET. However, when I test the same code on Mac OS X, it instead returns USOCKET:CONNECTION-REFUSED-ERROR, I think this is a behavior of BSD sockets.<br>
><br>
> I hope you can try latest usocket code from Git [1], to see if it works better for your case now. My code changes commit can be seen here [2].<br>
><br>
> For wait-for-input, I can’t see what you see (the socket object remains in a :READ state), if you still think this is an issue, I hope you can create another test code to demonstrate this issue.<br>
><br>
> Regards,<br>
><br>
> Chun<br>
><br>
> [1] <a href="https://github.com/usocket/usocket" target="_blank">https://github.com/usocket/usocket</a><br>
> [2] <a href="https://github.com/usocket/usocket/commit/13386639889fa812540fc4f77824c47e7616db37" target="_blank">https://github.com/usocket/usocket/commit/13386639889fa812540fc4f77824c47e7616db37</a><br>
><br>
> Il giorno 10/apr/2015, alle ore 23:00, Frank James <<a href="mailto:frank.a.james@gmail.com">frank.a.james@gmail.com</a>> ha scritto:<br>
><br>
> > I've been testing some UDP codes on Lispworks (personal 32bit Windows version) and have encountered some undocumented behaviour, I think it's a matter of opinion whether it's a bug or not but it should probably have a sentence or two documenting it somewhere.<br>
> ><br>
> > Basically I'm sending a UDP packet to a host and listening for a reply, using socket-send and socket-receive. If the host in question is not listening for UDP traffic on that particular port, the Windows socket API says it should return an ECONNRESET error immediately on the socket-receive call, this is indicated by a -1 return value from the underlying recvfrom call.<br>
> ><br>
> > When this happens the Lispworks backend code returns a length of -1 (and buffer nil). This is perfectly acceptable behaviour I think (although it'd be somewhat nicer to signal an error, but that's a matter of taste). But it should be documented that checking the length here is the correct way to detect an error occurred.<br>
> ><br>
> > Example code would be something like:<br>
> ><br>
> > (let ((sock (usocket:socket-connect "localhost" 1234 :protocol :datagram :element-type '(unsigned-byte 8))))<br>
> > (unwind-protect<br>
> > (progn<br>
> > (usocket:socket-send sock (make-array 16 :element-type '(unsigned-byte 8) :initial-element 0) 16)<br>
> > (let ((buffer (make-array 16 :element-type '(unsigned-byte 8) :initial-element 0)))<br>
> > (usocket:socket-receive sock buffer 16)))<br>
> > (usocket:socket-close sock)))<br>
> ><br>
> ><br>
> > What is somewhat more annoying is that the socket object remains in a :READ state. This means that a polling loop using wait-for-input spins continuously, with each socket-receive returning -1 (as explained above). Probably the socket state should be cleared if a socket-receive fails.<br>
> ><br>
> > Apologies if this is all well-known to those reading this list, but it caused me 10 minutes of head scratching earlier today and thought it was worth mentioning.<br>
> ><br>
> > Frank.<br>
> ><br>
><br>
><br>
><br>
</div></div>> <diff.lisp><br>
<br>
</blockquote></div><br></div>