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[Tcl-bugs] [ tcl-Bugs-597970 ] windows tcl server drops connections
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From: <no...@so...> - 2002-08-29 18:29:24
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Bugs item #597970, was opened at 2002-08-20 14:55 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=110894&aid=597970&group_id=10894 Category: 26. Channel Types Group: None Status: Open Resolution: Invalid Priority: 3 Submitted By: David N. Welton (davidw) Assigned to: Andreas Kupries (andreas_kupries) Summary: windows tcl server drops connections Initial Comment: I am running the following on Windows XP: --- set MyCounter 0 proc Cntr {args} { incr ::MyCounter puts "$args Counter ::MyCounter" } socket -server Cntr 8090 vwait forever --- And connecting to it with this: --- set numcon 50 set goodsockets 0 set badsockets 0 set i 0 while { $i < $numcon } { if { [catch { set sk [socket dwelton 80] fconfigure $sk -buffering line puts $sk {GET / HTTP/1.0 } } err] } { incr ::badsockets puts "$::badsockets bad sockets" } else { incr ::goodsockets puts "$::goodsockets good sockets" } incr i } --- The GET stuff is an artifact of this originally being used with tclhttpd, but doesn't really matter. The problem appears to be at a very low level. When I run tcpdump on the connection, it shows that the windows box is sending RST's after the other box sends a SYN - it's not even trying to connect. ---------------------------------------------------------------------- >Comment By: David N. Welton (davidw) Date: 2002-08-29 11:29 Message: Logged In: YES user_id=240 Really? That's ugly and complicated, and makes the simple case that much more difficult. What's more, it's not documented in the socket man page. If I get some time, I will try modifying things and see what I can see. ---------------------------------------------------------------------- Comment By: David Gravereaux (davygrvy) Date: 2002-08-28 17:31 Message: Logged In: YES user_id=7549 proc Cntr isn't 1) accepting the new channel with a [fileevent]. 2) declaring ::MyCounter as global. tcl8.0 I remember you could do a read/gets from the accept proc, but I don't think this is the case anymore. The missing global ::MyCounter is probably just a little typo and i'll infer it should be there. Using the attached scripts, I get this: server -> D:\>tclsh84 accept1_server.tcl Counter: 1 got "GET / HTTP/1.0" on 127.0.0.1:4001 Counter: 2 got "GET / HTTP/1.0" on 127.0.0.1:4002 Counter: 3 got "GET / HTTP/1.0" on 127.0.0.1:4003 Counter: 4 got "GET / HTTP/1.0" on 127.0.0.1:4004 Counter: 5 got "GET / HTTP/1.0" on 127.0.0.1:4005 Counter: 6 got "GET / HTTP/1.0" on 127.0.0.1:4006 Counter: 7 got "GET / HTTP/1.0" on 127.0.0.1:4007 Counter: 8 got "GET / HTTP/1.0" on 127.0.0.1:4008 Counter: 9 got "GET / HTTP/1.0" on 127.0.0.1:4009 Counter: 10 got "GET / HTTP/1.0" on 127.0.0.1:4010 Counter: 11 got "GET / HTTP/1.0" on 127.0.0.1:4011 Counter: 12 got "GET / HTTP/1.0" on 127.0.0.1:4012 Counter: 13 got "GET / HTTP/1.0" on 127.0.0.1:4013 Counter: 14 got "GET / HTTP/1.0" on 127.0.0.1:4014 Counter: 15 got "GET / HTTP/1.0" on 127.0.0.1:4015 Counter: 16 got "GET / HTTP/1.0" on 127.0.0.1:4016 Counter: 17 got "GET / HTTP/1.0" on 127.0.0.1:4017 Counter: 18 got "GET / HTTP/1.0" on 127.0.0.1:4018 Counter: 19 got "GET / HTTP/1.0" on 127.0.0.1:4019 Counter: 20 got "GET / HTTP/1.0" on 127.0.0.1:4020 Counter: 21 got "GET / HTTP/1.0" on 127.0.0.1:4021 Counter: 22 got "GET / HTTP/1.0" on 127.0.0.1:4022 Counter: 23 got "GET / HTTP/1.0" on 127.0.0.1:4023 Counter: 24 got "GET / HTTP/1.0" on 127.0.0.1:4024 Counter: 25 got "GET / HTTP/1.0" on 127.0.0.1:4025 Counter: 26 got "GET / HTTP/1.0" on 127.0.0.1:4026 Counter: 27 got "GET / HTTP/1.0" on 127.0.0.1:4027 Counter: 28 got "GET / HTTP/1.0" on 127.0.0.1:4028 Counter: 29 got "GET / HTTP/1.0" on 127.0.0.1:4029 Counter: 30 got "GET / HTTP/1.0" on 127.0.0.1:4030 Counter: 31 got "GET / HTTP/1.0" on 127.0.0.1:4031 Counter: 32 got "GET / HTTP/1.0" on 127.0.0.1:4032 Counter: 33 got "GET / HTTP/1.0" on 127.0.0.1:4033 Counter: 34 got "GET / HTTP/1.0" on 127.0.0.1:4034 Counter: 35 got "GET / HTTP/1.0" on 127.0.0.1:4035 Counter: 36 got "GET / HTTP/1.0" on 127.0.0.1:4036 Counter: 37 got "GET / HTTP/1.0" on 127.0.0.1:4037 Counter: 38 got "GET / HTTP/1.0" on 127.0.0.1:4038 Counter: 39 got "GET / HTTP/1.0" on 127.0.0.1:4039 Counter: 40 got "GET / HTTP/1.0" on 127.0.0.1:4040 Counter: 41 got "GET / HTTP/1.0" on 127.0.0.1:4041 Counter: 42 got "GET / HTTP/1.0" on 127.0.0.1:4042 Counter: 43 got "GET / HTTP/1.0" on 127.0.0.1:4043 Counter: 44 got "GET / HTTP/1.0" on 127.0.0.1:4044 Counter: 45 got "GET / HTTP/1.0" on 127.0.0.1:4045 Counter: 46 got "GET / HTTP/1.0" on 127.0.0.1:4046 Counter: 47 got "GET / HTTP/1.0" on 127.0.0.1:4047 Counter: 48 got "GET / HTTP/1.0" on 127.0.0.1:4048 Counter: 49 got "GET / HTTP/1.0" on 127.0.0.1:4049 Counter: 50 got "" on 127.0.0.1:4050 got "" on 127.0.0.1:4049 got "" on 127.0.0.1:4048 got "" on 127.0.0.1:4047 got "" on 127.0.0.1:4046 got "" on 127.0.0.1:4045 got "" on 127.0.0.1:4044 got "" on 127.0.0.1:4043 got "" on 127.0.0.1:4042 got "" on 127.0.0.1:4041 got "" on 127.0.0.1:4040 got "" on 127.0.0.1:4039 got "" on 127.0.0.1:4038 got "" on 127.0.0.1:4037 got "" on 127.0.0.1:4036 got "" on 127.0.0.1:4035 got "" on 127.0.0.1:4034 got "" on 127.0.0.1:4033 got "" on 127.0.0.1:4032 got "" on 127.0.0.1:4031 got "" on 127.0.0.1:4030 got "" on 127.0.0.1:4029 got "" on 127.0.0.1:4028 got "" on 127.0.0.1:4027 got "" on 127.0.0.1:4026 got "" on 127.0.0.1:4025 got "" on 127.0.0.1:4024 got "" on 127.0.0.1:4023 got "" on 127.0.0.1:4022 got "" on 127.0.0.1:4021 got "" on 127.0.0.1:4020 got "" on 127.0.0.1:4019 got "" on 127.0.0.1:4018 got "" on 127.0.0.1:4017 got "" on 127.0.0.1:4016 got "" on 127.0.0.1:4015 got "" on 127.0.0.1:4014 got "" on 127.0.0.1:4013 got "" on 127.0.0.1:4012 got "" on 127.0.0.1:4011 got "" on 127.0.0.1:4010 got "" on 127.0.0.1:4009 got "" on 127.0.0.1:4008 got "" on 127.0.0.1:4007 got "" on 127.0.0.1:4006 got "" on 127.0.0.1:4005 got "" on 127.0.0.1:4004 got "" on 127.0.0.1:4003 got "" on 127.0.0.1:4002 got "" on 127.0.0.1:4001 client -> D:\>tclsh84 accept_client.tcl 1 good sockets 2 good sockets 3 good sockets 4 good sockets 5 good sockets 6 good sockets 7 good sockets 8 good sockets 9 good sockets 10 good sockets 11 good sockets 12 good sockets 13 good sockets 14 good sockets 15 good sockets 16 good sockets 17 good sockets 18 good sockets 19 good sockets 20 good sockets 21 good sockets 22 good sockets 23 good sockets 24 good sockets 25 good sockets 26 good sockets 27 good sockets 28 good sockets 29 good sockets 30 good sockets 31 good sockets 32 good sockets 33 good sockets 34 good sockets 35 good sockets 36 good sockets 37 good sockets 38 good sockets 39 good sockets 40 good sockets 41 good sockets 42 good sockets 43 good sockets 44 good sockets 45 good sockets 46 good sockets 47 good sockets 48 good sockets 49 good sockets 50 good sockets I think the problem is assuming old 8.0 behavior in the original and not a problem with the core, IMO, of course. ---------------------------------------------------------------------- Comment By: David N. Welton (davidw) Date: 2002-08-21 11:11 Message: Logged In: YES user_id=240 dkf - you may be right, but the number is so low that it seems suspicious. Also worth noting is that on the same server, there is a 'service' running that is written in C. It can handle a lot of open connections with no problems. I was reaching 30 or more without one bad one, whereas with the tcl server I start getting bad ones at around 7 or 8, which seems way too low. The windows guys here don't seem to think it's on OS limit, either. ---------------------------------------------------------------------- Comment By: Donal K. Fellows (dkf) Date: 2002-08-21 02:42 Message: Logged In: YES user_id=79902 My initial suspicion is that your server is hitting a limit on the number of simultaneous open connections, given that you are not even attempting to close the connected sockets. Once you reach that point (which is generally an OS limit, though I don't know exactly the details of that) then all further connections will be closed (with a RST) because there is no hope of them successfully connecting. :^/ IIRC, the limit on Unix systems is higher (256 total FDs per process - which'd translate to 252 connections once you've allowed for stdio and the server socket - is a common limit, because of constraints on the size of select() buffer) but still exists. I'll let AKu close this if my suspicions are close enough to the truth... ---------------------------------------------------------------------- Comment By: David N. Welton (davidw) Date: 2002-08-20 14:59 Message: Logged In: YES user_id=240 I should mention: I ran the second script from a second (linux) box. When run locally, everything works as expected. When trying 50 connections, I get about 15 good sockets and 35 bad ones. I also investigated this being a windows limit, but it is apparently not the case with this OS. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=110894&aid=597970&group_id=10894 |