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• Check if line Index was changed in edit control

  - by John.SH

  Can i know or create a message which tells if the cursor moved to up or down a line in edit control?

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• VBS Script for modifying multi-value Active Directory display specifier

  - by sh-beta

  Following the howto Extending the Active Directory Schema To Track Custom Info I'm able to setup a single-value schema attribute that is easily changeable via a context menu in ADUC. Multi-value schema attributes get considerably more complicated. Say (for the sake of argument) my value is "Projects" and each user may be a list as many projects as necessary. Following is a sad little script that will set Project to a single value: Dim oproject Dim oUser1 Dim temp1 Set oproject = Wscript.Arguments Set oUser1 = GetObject(oproject(0)) temp1 = InputBox("Project: " & oUser1.project & vbCRLF & vbCRLF & "Project") if temp1 <> "" then oUser1.Put "project",temp1 oUser1.SetInfo Set oUser1 = Nothing Set oproject = Nothing Set temp1 = Nothing WScript.Quit How can I modify this to allow, assign, and modify multiple values?

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• Doctrine Many to Many

  - by Ru Sh

  Hello, I have a question about Doctrine ORM M:M. I built some tables like this: -User +id +name -Group +id +name I want to link these table via a new table with Doctrine: $this->hasMany('User as Users', array( // I'm wondering what I can fill here 'refClass' => 'Usercategory' )); Please help me fill the blank. Thanks. Looking forward to hearing from you soon. P/S:Sorry for my English

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• Building NDK app with Android ADT on Windows

  - by Michael Sh

  While there are tons of information on the topic, there is no clear guide on how to compile C++ code in ADT. Is Cygwin is required? Where the build artifacts go? How to confogure the destination folder for the build package? Are there a debug and release versions? Is it possible to debug and step through the C++ code in ADT? Maybe it all is described in a single resource, then a link would be welcome!

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• PHP to C# and Vice versa

  - by Daniel Sh.

  I'm in this project: A web page that's gonna be used by the front-end company people to query and update data from a SQL DB. I'm working with visual studio and the code behind (C#) is almost done, so the interactions between SQL and C# and ok. My original idea was to work with ASP.NET which is familiar to me, but that's not gonna be possible. I have to switch to PHP. So, today is my first day learning PHP, checking http://php.net/manual/en/index.php and a lot of things seem quite similar to ASP.NET so I guess it won't be that hard. Anyways, some questions popped up quite fast as I wanted to script something else than a "hello world" . Is there an easy way to get/send C# variables from my class using a php page? I've read soemthing about using XML in order to do so, but still I'm scratching my head, is there another, easier, way to do this?

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• How to protect an ASP Classic Page?

  - by SH

  How can I protect an ASP Classic page with either HTTP AUTH (you must provide a username and password to service) or a randomly generated access key that will be included as one of the parameters of the HTTP POST using the variable name access_key. Can anybody provide asp classic code in this regard? Quick help will be appreciated... PS: OrderGroove is a 3rd party service... neglect it.

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• Asp.Net Cookie sharing

  - by SH

  This is C#.Net code: How to share Cookie between 2 HttpWebRequest calls? Details: I am posting a form in first request, this form contains some setting variables which are used by the system. lets say there is a input field in the form which sets the size of grid pages to be displayed in other pages. Once i have updated the setings in previous request, i go to send a request to another page which shows off asp.net gridview/grid. The grid might contaian several pages and the page size should be the one which i set in previous request. But when i do this via HttpWebReeust it does not happen. When i do it via browser, loading the setting page in the browser and then going to the grid view page... i see the page size is updated. I want to achieve this via code. Sicne i am scraping this grid. i have to set page size or visit the gird pages one by one via code. Or is it possible to set a cookie on 2nd request which is used to set in first request? It will be great if i go this way. any solution?

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• Asp.Net Scrapping Grid Pages

  - by SH

  I need cod in C#. Look, i am trying to post the search.aspx page which contains Asp.Net grid. When grid is rendered it loads very first page on the screen and then there are number of pages in the grid header. I scrap first page, and now i want to move on to the next page. All this is being done using following code: HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("http://pubrec3.hillsclerk.com/oncore/search.aspx?" + param); myRequest.Method = "GET"; myRequest.KeepAlive = false; HttpWebResponse webresponse; try { webresponse = (HttpWebResponse)myRequest.GetResponse(); Encoding enc = System.Text.Encoding.GetEncoding(1252); StreamReader loResponseStream = new StreamReader(webresponse.GetResponseStream(), enc); string r = loResponseStream.ReadToEnd(); loResponseStream.Close(); webresponse.Close(); //if (GetRecordCount(r)) ExtractResultTable(bd, ed, r); } catch (Exception ex) { } The above code grabs first page... and now i have to move on to the next page. This is the link which produces a grid with 3 pages. http://pubrec3.hillsclerk.com/oncore/search.aspx?bd=01/01/2008&ed=12/31/2008&bt=O&lb=1000000&ub=1000000000&d=5/6/2010&pt=-1&dt=D,%20MTG&st=consideration Using above code i need to load the 2nd page with the same search criteria but the records found in 2nd page. and then so on. I know there is a trick to navigate through the grid pages. I used it but it did not work on this page. the trick is, you can pass __EVENTTARGET and __EVENTARGUMENT in query string to navigate through the gird but it does not work on this website. I am desperately searching a way, how to cope with this website. i really want this done. i do not want any code but a way to nevigate throgh the grid using query string if it does work. Otherwise please be specific to the problem.

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• Can I find a filename from a filehandle in Perl?

  - by sh-beta

  open(my $fh, '>', $path) || die $!; my_sub($fh); Can my_sub() somehow extrapolate $path from $fh?

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• How to stop my emails to be sent as bulk email?

  - by SH

  I have a reason to do that. I have recorded a voice message, attached with email, and sent it to several companies. One company, takes that voice message/email, and send it to millions of people. I want to stop resend of my email/voice recording. I am C# develop, one of my client asked me this question. I asked him to introduce verification codes, so that nobody will be able to listen the voice but still emails would be sent to millions of poeple. Any workaround for this problem?

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• How to Send and Receive XML request to another ASP classic page?

  - by SH

  I want to send an XML to another Asp Classic page on the same domain. i am using following code for sending XMl url = "http://localhost/api/xmlget.asp" information = "ColtTaylor100" Set xmlhttp = server.Createobject("MSXML2.ServerXMLHTTP") xmlhttp.Open "POST", url, false xmlhttp.setRequestHeader "Content-Type", "text/xml" xmlhttp.send information And i have setup xmlget.asp with following code to receive XML: Dim xmlDoc Dim userName set xmlDoc=Server.CreateObject("Microsoft.XMLDOM") xmlDoc.async="false" xmlDoc.load(Request) I run the code but do not see any reflection, how would i know? And if it is successful I want to know the xml and i dont know exact property to load from xmlDoc!

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• Navigate through .Net Grid

  - by SH

  is there a way to navigate through gird found on this page by passing parameters in query string? http://pubrec3.hillsclerk.com/oncore/search.aspx?bd=01/01/2008&ed=12/31/2008&bt=O&lb=1000000&ub=1000000000&d=5/6/2010&pt=-1&dt=D,%20MTG&st=consideration Or any code suggestion? All example could i need in C#.

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• How to project an ASP Classic Page?

  - by SH

  How to project an ASP Classic page with either HTTP AUTH (you must provide a username and password to OrderGroove) or a randomly generated access key that will be included as one of the parameters of the HTTP POST using the variable name access_key. Can anybody provide asp classic code in this regard? Quick help will be appreciated...

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• Mp3 Header information edit

  - by SH

  I want to edit the header information of an existing MP3 file. Can any one suggest how to achieve it in C#.net?

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• Any work around to restrict my email recepient to send it to others?

  - by SH

  Is there a way to if somebody receives my email, and s/he can not forward it to others?

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• How to schedule a webpage to be executed on daily basis on shared hosting?

  - by SH

  Hi there, I i want to schedule an asp.net page on my hosting, how to achieve it? for instance, i have a page named myservice.aspx runing on my website.com/myservice.aspx i want to run this page on every 24 hours. any idea?

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• Build-Essentials installation failing

  - by Brickman

  I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo] password for: Reading package lists... Done Building dependency tree Reading state information... Done build-essential is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. :~$ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. :~$ Dump of headers after installation attempts. > /usr/include/boost/interprocess/detail/atomic.hpp > /usr/include/boost/interprocess/smart_ptr/detail/sp_counted_base_atomic.hpp > /usr/include/qt4/Qt/qatomic.h /usr/include/qt4/Qt/qbasicatomic.h > /usr/include/qt4/QtCore/qatomic.h > /usr/include/qt4/QtCore/qbasicatomic.h > /usr/share/doc/git-annex/html/bugs/git_annex_unlock_is_not_atomic.html > /usr/src/linux-headers-3.11.0-15/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-15/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-15/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-15/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-15/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-15/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-15-generic/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-17/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-17/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-17/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-17/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-17/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-17-generic/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-18/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-18/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-18/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-18/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-18/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-18-generic/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-19/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-19/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-19/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-19/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-19/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-19-generic/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-20/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-20/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-20/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-20/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-20/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-20-generic/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/h8300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.11.0-22/include/asm-generic/atomic.h > /usr/src/linux-headers-3.11.0-22/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.11.0-22/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.11.0-22/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.11.0-22/include/linux/atomic.h > /usr/src/linux-headers-3.11.0-22-generic/include/linux/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/alpha/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/arc/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/arm/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/arm64/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/avr32/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/blackfin/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/cris/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/frv/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/hexagon/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/ia64/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/m32r/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/m68k/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/metag/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/microblaze/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/mips/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/mn10300/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/parisc/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/powerpc/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/s390/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/score/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/sh/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/sparc/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/tile/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/x86/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/arch/xtensa/include/asm/atomic.h > /usr/src/linux-headers-3.14.4-031404/include/asm-generic/atomic.h > /usr/src/linux-headers-3.14.4-031404/include/asm-generic/bitops/atomic.h > /usr/src/linux-headers-3.14.4-031404/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-headers-3.14.4-031404/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-headers-3.14.4-031404/include/linux/atomic.h > /usr/src/linux-headers-3.14.4-031404-generic/include/linux/atomic.h > /usr/src/linux-headers-3.14.4-031404-lowlatency/include/linux/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/alpha/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/arc/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/arm/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/arm64/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/avr32/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/blackfin/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/cris/include/arch-v10/arch/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/cris/include/arch-v32/arch/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/cris/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/frv/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/h8300/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/hexagon/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/ia64/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/m32r/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/m68k/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/metag/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/microblaze/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/mips/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/mn10300/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/parisc/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/powerpc/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/s390/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/score/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/sh/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/sparc/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/tile/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/x86/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/arch/xtensa/include/asm/atomic.h > /usr/src/linux-lts-saucy-3.11.0/include/asm-generic/atomic.h > /usr/src/linux-lts-saucy-3.11.0/include/asm-generic/bitops/atomic.h > /usr/src/linux-lts-saucy-3.11.0/include/asm-generic/bitops/ext2-atomic.h > /usr/src/linux-lts-saucy-3.11.0/include/asm-generic/bitops/non-atomic.h > /usr/src/linux-lts-saucy-3.11.0/include/linux/atomic.h > /usr/src/linux-lts-saucy-3.11.0/ubuntu/lttng/lib/ringbuffer/vatomic.h > /usr/src/linux-lts-saucy-3.11.0/ubuntu/lttng/wrapper/ringbuffer/vatomic.h > /usr/src/linux-lts-saucy-3.11.0/ubuntu/lttng-modules/lib/ringbuffer/vatomic.h > /usr/src/linux-lts-saucy-3.11.0/ubuntu/lttng-modules/wrapper/ringbuffer/vatomic.h Yes, I know there are multiple headers of the same type here, but they are different versions. Version "linux-headers-3.14.4-031404" shows to be the latest. Ubuntu shows "Nothing needed to be installed." However, the following C/C++ headers files show to be missing for Eclipse and QT4. #include <linux/version.h> #include <linux/module.h> #include <linux/socket.h> #include <linux/miscdevice.h> #include <linux/list.h> #include <linux/vmalloc.h> #include <linux/slab.h> #include <linux/init.h> #include <asm/uaccess.h> #include <asm/atomic.h> #include <linux/delay.h> #include <linux/usb.h> This problem appears on my 32-bit version of Ubuntu and on both of my 64-bit versions. What I am doing wrong?

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• C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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• C#/.NET Little Wonders: The ConcurrentDictionary

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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• Why do I start at privilege level 1 when logging into a Cisco ASA 5510?

  - by Alain O'Dea

  I have created a test user that is set to privilege 15 in the config: username test password **************** encrypted privilege 15 When I log in to the ASA 5510 I am in privilege 1 according to sh curpriv: login as: test [email protected]'s password: Type help or '?' for a list of available commands. asa> sh curpriv Username : test Current privilege level : 1 Current Mode/s : P_UNPR Attempting enable fails even though I know I have the correct enable password: asa> en Password: ************************* Password: ************************* Password: ************************* Access denied. Logging in from unprivileged puts me on privilege 15 and I can do as a please: asa> login Username : test Pasword: ************************* asa> sh curpriv Current privilege level : 15 Current Mode/s : P_PRIV asa> The only thing I can track this to is a configuration change I made where I removed a VPN user we no longer needed. Why do I start at privilege level 1 when logging into a Cisco ASA 5510?

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• Linux - Only first virtual interface can ping external gateway

  - by husvar

  I created 3 virtual interfaces with different mac addresses all linked to the same physical interface. I see that they successfully arp for the gw and they can ping (the request is coming in the packet capture in wireshark). However the ping utility does not count the responses. Does anyone knows the issue? I am running Ubuntu 14.04 in a VmWare. root@ubuntu:~# ip link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff inet6 fe80::20c:29ff:febc:fc8b/64 scope link valid_lft forever preferred_lft forever root@ubuntu:~# ip route sh root@ubuntu:~# ip link add link eth0 eth0.1 addr 00:00:00:00:00:11 type macvlan root@ubuntu:~# ip link add link eth0 eth0.2 addr 00:00:00:00:00:22 type macvlan root@ubuntu:~# ip link add link eth0 eth0.3 addr 00:00:00:00:00:33 type macvlan root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh root@ubuntu:~# dhclient -v eth0.1 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.1/00:00:00:00:00:11 Sending on LPF/eth0.1/00:00:00:00:00:11 Sending on Socket/fallback DHCPDISCOVER on eth0.1 to 255.255.255.255 port 67 interval 3 (xid=0x568eac05) DHCPREQUEST of 192.168.1.145 on eth0.1 to 255.255.255.255 port 67 (xid=0x568eac05) DHCPOFFER of 192.168.1.145 from 192.168.1.254 DHCPACK of 192.168.1.145 from 192.168.1.254 bound to 192.168.1.145 -- renewal in 1473 seconds. root@ubuntu:~# dhclient -v eth0.2 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.2/00:00:00:00:00:22 Sending on LPF/eth0.2/00:00:00:00:00:22 Sending on Socket/fallback DHCPDISCOVER on eth0.2 to 255.255.255.255 port 67 interval 3 (xid=0x21e3114e) DHCPREQUEST of 192.168.1.146 on eth0.2 to 255.255.255.255 port 67 (xid=0x21e3114e) DHCPOFFER of 192.168.1.146 from 192.168.1.254 DHCPACK of 192.168.1.146 from 192.168.1.254 bound to 192.168.1.146 -- renewal in 1366 seconds. root@ubuntu:~# dhclient -v eth0.3 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.3/00:00:00:00:00:33 Sending on LPF/eth0.3/00:00:00:00:00:33 Sending on Socket/fallback DHCPDISCOVER on eth0.3 to 255.255.255.255 port 67 interval 3 (xid=0x11dc5f03) DHCPREQUEST of 192.168.1.147 on eth0.3 to 255.255.255.255 port 67 (xid=0x11dc5f03) DHCPOFFER of 192.168.1.147 from 192.168.1.254 DHCPACK of 192.168.1.147 from 192.168.1.254 bound to 192.168.1.147 -- renewal in 1657 seconds. root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.145/24 brd 192.168.1.255 scope global eth0.1 valid_lft forever preferred_lft forever 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.146/24 brd 192.168.1.255 scope global eth0.2 valid_lft forever preferred_lft forever 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.147/24 brd 192.168.1.255 scope global eth0.3 valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh default via 192.168.1.254 dev eth0.1 192.168.1.0/24 dev eth0.1 proto kernel scope link src 192.168.1.145 192.168.1.0/24 dev eth0.2 proto kernel scope link src 192.168.1.146 192.168.1.0/24 dev eth0.3 proto kernel scope link src 192.168.1.147 root@ubuntu:~# arping -c 5 -I eth0.1 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.145 eth0.1 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 6.936ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.986ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 0.654ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.137ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.426ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.2 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.146 eth0.2 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.665ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.753ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 16.500ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.287ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 32.438ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.3 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.147 eth0.3 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 4.422ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.429ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.321ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 40.423ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.268ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# tcpdump -n -i eth0.1 -v & [1] 5317 root@ubuntu:~# ping -c5 -q -I eth0.1 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.145 eth0.1: 56(84) bytes of data. tcpdump: listening on eth0.1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:37.612558 IP (tos 0x0, ttl 64, id 2595, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 2, length 64 13:18:37.618864 IP (tos 0x68, ttl 64, id 14493, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 2, length 64 13:18:37.743650 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:38.134997 IP (tos 0x0, ttl 128, id 23547, offset 0, flags [none], proto UDP (17), length 229) 192.168.1.86.138 > 192.168.1.255.138: NBT UDP PACKET(138) 13:18:38.614580 IP (tos 0x0, ttl 64, id 2596, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 3, length 64 13:18:38.793479 IP (tos 0x68, ttl 64, id 14495, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 3, length 64 13:18:39.151282 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:39.615612 IP (tos 0x0, ttl 64, id 2597, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 4, length 64 13:18:39.746981 IP (tos 0x68, ttl 64, id 14496, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 4, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4008ms rtt min/avg/max/mdev = 2.793/67.810/178.934/73.108 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 12 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.1 -v root@ubuntu:~# tcpdump -n -i eth0.2 -v & [1] 5320 root@ubuntu:~# ping -c5 -q -I eth0.2 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.146 eth0.2: 56(84) bytes of data. tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:41.536874 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.254 is-at 58:98:35:57:a0:70, length 46 13:18:41.536933 IP (tos 0x0, ttl 64, id 2599, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 1, length 64 13:18:41.539255 IP (tos 0x68, ttl 64, id 14507, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 1, length 64 13:18:42.127715 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:42.511725 IP (tos 0x0, ttl 64, id 2600, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 2, length 64 13:18:42.514385 IP (tos 0x68, ttl 64, id 14527, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 2, length 64 13:18:42.743856 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:43.511727 IP (tos 0x0, ttl 64, id 2601, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 3, length 64 13:18:43.513768 IP (tos 0x68, ttl 64, id 14528, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 3, length 64 13:18:43.637598 IP (tos 0x0, ttl 128, id 23551, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.641185 IP (tos 0x0, ttl 128, id 23552, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 192.168.1.255.17500: UDP, length 197 13:18:43.641201 IP (tos 0x0, ttl 128, id 23553, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.743890 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:44.510758 IP (tos 0x0, ttl 64, id 2602, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 4, length 64 13:18:44.512892 IP (tos 0x68, ttl 64, id 14538, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 4, length 64 13:18:45.510794 IP (tos 0x0, ttl 64, id 2603, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 5, length 64 13:18:45.519701 IP (tos 0x68, ttl 64, id 14539, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 5, length 64 13:18:49.287554 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:50.013463 IP (tos 0x0, ttl 255, id 50737, offset 0, flags [DF], proto UDP (17), length 73) 192.168.1.146.5353 > 224.0.0.251.5353: 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:50.218874 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:51.129961 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:52.197074 IP6 (hlim 255, next-header UDP (17) payload length: 53) 2001:818:d812:da00:200:ff:fe00:22.5353 > ff02::fb.5353: [udp sum ok] 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:54.128240 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4000ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 13:18:54.657731 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:54.743174 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 25 packets captured 26 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.2 -v root@ubuntu:~# tcpdump -n -i eth0.3 icmp & [1] 5324 root@ubuntu:~# ping -c5 -q -I eth0.3 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.147 eth0.3: 56(84) bytes of data. tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0.3, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:56.373434 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 1, length 64 13:18:57.372116 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 2, length 64 13:18:57.381263 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 2, length 64 13:18:58.371141 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 3, length 64 13:18:58.373275 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 3, length 64 13:18:59.371165 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 4, length 64 13:18:59.373259 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 4, length 64 13:19:00.371211 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 5, length 64 13:19:00.373278 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 5, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 1 received, 80% packet loss, time 4001ms rtt min/avg/max/mdev = 13.666/13.666/13.666/0.000 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 10 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.3 icmp root@ubuntu:~# arp -n Address HWtype HWaddress Flags Mask Iface 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.1 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.2 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.3

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• OpenVPN on ec2 bridged mode connects but no Ping, DNS or forwarding

  - by michael

  I am trying to use OpenVPN to access the internet over a secure connection. I have openVPN configured and running on Amazon EC2 in bridge mode with client certs. I can successfully connect from the client, but I cannot get access to the internet or ping anything from the client I checked the following and everything seems to shows a successful connection between the vpn client/server and UDP traffic on 1194 [server] sudo tcpdump -i eth0 udp port 1194 (shows UDP traffic after establishing connection) [server] sudo iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination [server] sudo iptables -L -t nat Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination MASQUERADE all -- ip-W-X-Y-0.us-west-1.compute.internal/24 anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination [server] openvpn.log Wed Oct 19 03:11:26 2011 localhost/a.b.c.d:61905 [localhost] Inactivity timeout (--ping-restart), restarting Wed Oct 19 03:11:26 2011 localhost/a.b.c.d:61905 SIGUSR1[soft,ping-restart] received, client-instance restarting Wed Oct 19 03:41:31 2011 MULTI: multi_create_instance called Wed Oct 19 03:41:31 2011 a.b.c.d:57889 Re-using SSL/TLS context Wed Oct 19 03:41:31 2011 a.b.c.d:57889 LZO compression initialized Wed Oct 19 03:41:31 2011 a.b.c.d:57889 Control Channel MTU parms [ L:1574 D:166 EF:66 EB:0 ET:0 EL:0 ] Wed Oct 19 03:41:31 2011 a.b.c.d:57889 Data Channel MTU parms [ L:1574 D:1450 EF:42 EB:135 ET:32 EL:0 AF:3/1 ] Wed Oct 19 03:41:31 2011 a.b.c.d:57889 Local Options hash (VER=V4): '360696c5' Wed Oct 19 03:41:31 2011 a.b.c.d:57889 Expected Remote Options hash (VER=V4): '13a273ba' Wed Oct 19 03:41:31 2011 a.b.c.d:57889 TLS: Initial packet from [AF_INET]a.b.c.d:57889, sid=dd886604 ab6ebb38 Wed Oct 19 03:41:35 2011 a.b.c.d:57889 VERIFY OK: depth=1, /C=US/ST=CA/L=SanFrancisco/O=EXAMPLE/CN=EXAMPLE_CA/[email protected] Wed Oct 19 03:41:35 2011 a.b.c.d:57889 VERIFY OK: depth=0, /C=US/ST=CA/L=SanFrancisco/O=EXAMPLE/CN=localhost/[email protected] Wed Oct 19 03:41:37 2011 a.b.c.d:57889 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key Wed Oct 19 03:41:37 2011 a.b.c.d:57889 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Wed Oct 19 03:41:37 2011 a.b.c.d:57889 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key Wed Oct 19 03:41:37 2011 a.b.c.d:57889 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Wed Oct 19 03:41:37 2011 a.b.c.d:57889 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 1024 bit RSA Wed Oct 19 03:41:37 2011 a.b.c.d:57889 [localhost] Peer Connection Initiated with [AF_INET]a.b.c.d:57889 Wed Oct 19 03:41:39 2011 localhost/a.b.c.d:57889 PUSH: Received control message: 'PUSH_REQUEST' Wed Oct 19 03:41:39 2011 localhost/a.b.c.d:57889 SENT CONTROL [localhost]: 'PUSH_REPLY,redirect-gateway def1 bypass-dhcp,route-gateway W.X.Y.Z,ping 10,ping-restart 120,ifconfig W.X.Y.Z 255.255.255.0' (status=1) Wed Oct 19 03:41:40 2011 localhost/a.b.c.d:57889 MULTI: Learn: (IPV6) -> localhost/a.b.c.d:57889 [client] tracert google.com Tracing route to google.com [74.125.71.104] over a maximum of 30 hops: 1 347 ms 349 ms 348 ms PC [w.X.Y.Z] 2 * * * Request timed out. I can also successfully ping the server IP address from the client, and ping google.com from an SSH shell on the server. What am I doing wrong? Here is my config (Note: W.X.Y.Z == amazon EC2 private ipaddress) bridge config on br0 ifconfig eth0 0.0.0.0 promisc up brctl addbr br0 brctl addif br0 eth0 ifconfig br0 W.X.Y.X netmask 255.255.255.0 broadcast W.X.Y.255 up route add default gw W.X.Y.1 br0 /etc/openvpn/server.conf (from https://help.ubuntu.com/10.04/serverguide/C/openvpn.html) local W.X.Y.Z dev tap0 up "/etc/openvpn/up.sh br0" down "/etc/openvpn/down.sh br0" ;server W.X.Y.0 255.255.255.0 server-bridge W.X.Y.Z 255.255.255.0 W.X.Y.105 W.X.Y.200 ;push "route W.X.Y.0 255.255.255.0" push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 208.67.222.222" push "dhcp-option DNS 208.67.220.220" tls-auth ta.key 0 # This file is secret user nobody group nogroup log-append openvpn.log iptables config sudo iptables -A INPUT -i tap0 -j ACCEPT sudo iptables -A INPUT -i br0 -j ACCEPT sudo iptables -A FORWARD -i br0 -j ACCEPT sudo iptables -t nat -A POSTROUTING -s W.X.Y.0/24 -o eth0 -j MASQUERADE echo 1 > /proc/sys/net/ipv4/ip_forward Routing Tables added route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface W.X.Y.0 0.0.0.0 255.255.255.0 U 0 0 0 br0 0.0.0.0 W.X.Y.1 0.0.0.0 UG 0 0 0 br0 C:>route print =========================================================================== Interface List 32...00 ff ac d6 f7 04 ......TAP-Win32 Adapter V9 15...00 14 d1 e9 57 49 ......Microsoft Virtual WiFi Miniport Adapter #2 14...00 14 d1 e9 57 49 ......Realtek RTL8191SU Wireless LAN 802.11n USB 2.0 Net work Adapter 10...00 1f d0 50 1b ca ......Realtek PCIe GBE Family Controller 1...........................Software Loopback Interface 1 11...00 00 00 00 00 00 00 e0 Teredo Tunneling Pseudo-Interface 16...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter 17...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #2 18...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #3 36...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #5 =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.1.2.1 10.1.2.201 25 10.1.2.0 255.255.255.0 On-link 10.1.2.201 281 10.1.2.201 255.255.255.255 On-link 10.1.2.201 281 10.1.2.255 255.255.255.255 On-link 10.1.2.201 281 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 10.1.2.201 281 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 10.1.2.201 281 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 0.0.0.0 0.0.0.0 10.1.2.1 Default =========================================================================== C:>tracert google.com Tracing route to google.com [74.125.71.147] over a maximum of 30 hops: 1 344 ms 345 ms 343 ms PC [W.X.Y.221] 2 * * * Request timed out.

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• SmartSVN - Unable to create new repository profile

  - by Sandeepan Nath

  I have just installed SmartSVN on this fedora system. The application starts (on running ./smartsvn.sh) with its usual UI but many things are not working. Creating New repository profile Trying to create a new repository profile (Repositories- Repository Profiles- Add) An Error occurred while processing an SVN command - Cannot connect to 'svn+ssh://192.168.0.103': There was a problem while connecting to 192.168.0.103:22 Quick Checkout Trying to do Quick Checkout (less configuration) An Error occurred while processing an SVN command - Malformed XML. Some Observations When I run the smartsvn.sh file like this:- ./smartsvn.sh It shows this in the console - Warning: /bin/java does not exist Could not lock /root/.smartsvn/_lock_ Switched to running instance I was using SmartSVN in another system before this where it was working. There too, it was showing the warning like Warning: /bin/java does not exist but this part was not showing:- Could not lock /root/.smartsvn/_lock_ Switched to running instance I have only JRE installed in both the systems and not JDK. So, what could be the reason? Any pointers? Thanks, Sandeepan

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• dansguardian error: filterports must match number of filterips (pfsense)

  - by Bulki

  Hi I'm setting up pfsense with squid3 and dansguardian packages. When I try to start the dansguardian service however, I get the following errors: May 27 22:17:37 php: /pkg_edit.php: The command '/usr/local/etc/rc.d/dansguardian.sh start' returned exit code '1', the output was 'kern.ipc.somaxconn: 16384 -> 16384 kern.maxfiles: 131072 -> 131072 kern.maxfilesperproc: 104856 -> 104856 kern.threads.max_threads_per_proc: 4096 -> 4096 Starting dansguardian. filterports (2) must match number of filterips (1) Error parsing the dansguardian.conf file or other DansGuardian configuration files /usr/local/etc/rc.d/dansguardian.sh: WARNING: failed to start dansguardian' May 27 22:17:37 root: /usr/local/etc/rc.d/dansguardian.sh: WARNING: failed to start dansguardian May 27 22:17:37 dansguardian[52944]: Error parsing the dansguardian.conf file or other DansGuardian configuration files May 27 22:17:37 dansguardian[52944]: filterports must match number of filterips What does "filterports must match number of filterips" mean? Any thoughts on the matter?

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• execute a command in all subdirectories bash

  - by Luigi R. Viggiano

  I have a directory structure composed by: iTunes/Music/${author}/${album}/${song.mp3} I implemented a script to strip my mp3 bitrate to 128 kbps using lame (which works on a single file at time). My script looks like this 'normalize_mp3.sh': #!/bin/bash SAVEIFS=$IFS IFS=$(echo -en "\n\b") for f in *.mp3 do lame --cbr $f __out.mp3 mv __out.mp3 $f done IFS=$SAVEIFS This works fine, if I go folder by folder and execute this command. But I'd like to have a "global" command, like in 4DOS so I can run: $ cd iTunes/Music $ global normalize_mp3.sh and the global command would traverse all subdirs and execute the normalize_mp3.sh to strip all my mp3 in all subfolders. Anyone knows if there is a unix equivalent to the 4dos global command? I tried to play with find -exec but I just managed to get an headache.

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