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  • question about pcap

    - by scatman
    hi, i have to do a sniffer as an assignment for the security course. i am using c and the pcap library. i got everything working well (since i got a code from the internet and changed it). but i have some questions about the code. u_int ip_len = (ih->ver_ihl & 0xf) * 4; ih is of type ip_header, and its currently pointing the to ip header in the packet. ver_ihl gives the version of the ip i can't figure out what is: & 0xf) * 4; any help?

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  • How large should my recv buffer be when calling recv in the socket library

    - by Silmaril89
    Hi, I have a few questions about the socket library in C. Here is a snippet of code I'll refer to in my questions. char recv_buffer[3000]; recv(socket, recv_buffer, 3000, 0); First, How do I decide how big to make recv_buffer? I'm using 3000, but it's arbitrary. Second, what happens if recv() receives a packet bigger than my recv_buffer? Third, how can I know if I have received the entire message without calling recv again and have it wait forever when there is nothing to be received? And finally, is there a way I can make a buffer not have a fixed amount of space, so that I can keep adding to it without fear of running out of space? maybe using strcat to concatenate the latest recv() response to the buffer? I know it's a lot of questions in one, but I would greatly appreciate any responses.

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  • Where is a good place for a code review?

    - by Carlos Nunez
    Hi, all! A few colleagues and I created a simple packet capturing application based on libpcap, GTK+ and sqlite as a project for a Networks Engineering course at our university. While it (mostly) works, I am trying to improve my programming skills and would appreciate it if members of the community could look at what we've put together. Is this a good place to ask for such a review? If not, what are good sites I can throw this question up on? The source code is hosted by Google Code (http://code.google.com/p/nbfm-sniffer) and an executable is available for download (Windows only, though it does compile on Linux and should compile on OS X Leopard as well provided one has gtk+ SDK installed). Thanks, everyone! -Carlos Nunez

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  • Benchmark for a .NET WinPcap wrapper

    - by brickner
    I'm developing a .NET wrapper for WinPcap called Pcap.Net. I'm trying to make sure this wrapper has high performance and I want to compare it to WinPcap and to other .net wrappers for WinPcap. The features I want to profile are: WinPcap native features (sending packets in different ways, receiving packets in different ways...) Interpreting packets that Pcap.Net knows how to interpret (like Etherent, IPv4, UDP, TCP, ICMP, ...) Building packet that Pcap.Net knows how to build (the same types it knows how to interpret). I also want to be able to profile the benchmark using Visual Studio 2010 Ultimate profiling tools. My question is: What should my benchmark exactly do to cover these issues and how would you suggest to build it?

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  • Packing a long binary integer in Ruby

    - by user1056142
    I'm trying to send a very long binary integer over UDP (on the order of 200 bits). When I try to use Array's pack method, it complains the string I'm trying to convert is too large. Am I going about this the wrong way? ruby-1.8.7-p352 :003 > [0b1101001010101101111010100101010011010101010110010101010101010010010101001010101010101011101010101010101111010101010101010101].pack('i') RangeError: bignum too big to convert into `unsigned long' from (irb):3:in `pack' from (irb):3 This number is supposed to represent a DNS query packet (this is for a homework assignment; we're not allowed to use any DNS libraries).

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  • linux: disable using loopback and send data via wire between 2 eth cards of one comp

    - by osgx
    Hello I have a comp with 2 eth cards, connected with patch-cord (direct eth. cable from 1st to 2nd). The linux is installed, I want to send data from 1st network card to 2nd. And I want to force the packet to pass via cable. I can set up any ip on cards. With ping I get counters on cards constant. Is it possible with tcp/ip sockets? PS. I need to write a program. which will send packets via eth, so stackoverflow-related question. There can be some OS-dependent way, they will help me too

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  • Injecting raw TCP packets with Python

    - by Evgeniy Arbatov
    Hello! What would be a suitable way to inject a raw TCP packet with Python? For example, I have the payload consisting of hexadecimal numbers and I want to send that sequence of hexadecimal numbers to a network daemon: so that if I choose to send 'abcdef', I see 'abcdef' on the wire too. But not '6162636566' as in the case of: new = socket.socket(socket.AF_INET, socket.SOCK_STREAM) new.connect(('127.0.0.1', 9999)) new.send('abcdef') Can I use Python's SOCK_RAW for this purpose? If so, can you give me an example of sending raw TCP packets with SOCK_RAW (since I did not get it working myself) Thanks! Evgeniy

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  • iOS Efficiency File Saving Efficiency

    - by Guvvy Aba
    I was working on my iOS app and my goal is to save a file that I am receiving from the internet bit by bit. My current setup is that I have a NSMutableData object and I add a bit of data to it as I receive my file. After the last "packet" is received, I write the NSData to a file and the process is complete. I'm kind of worried that this isn't the ideal way to do it because of the limitations of RAM in a mobile device and it would be problematic to receive large files. My next thought was to implement a NSFileHandle so that as the file arrives, it would be saved to the disk, rather than the virtual memory. In terms of speed and efficiency, which method do you think will work decently on an iOS device. I am currently using the first, NSMutableData approach. Is it worth changing my app to use the NSFileHandle? Thanks in advance, Guvvy

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  • Using Active Objects and BLOBs

    - by Andrew L.
    I am in a group of people who are creating a Defect Tracking program as a project. We have been using Active Objects and have run into some issues. Currently maximum file size for the blob is approx. 2Mb but we want to be able to increase it up to 2Gb. We currently have been looking at many sites and have not been able to find out how to increase the size. We are currently storing the blob as an array of bytes. Our current error says, Packet for Query is too large? We don't know how to set the variable, and we don't know how to set it using AO. We are programming this in Java, too. We are wondering if anyone has a solution to this problem. Thanks for the Help.

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  • AudioQueueOfflineRender returning empty data

    - by hyn
    I'm having problems using AudioQueueOfflineRender to decode AAC data. When I examine the buffer after the call, it is always filled with empty data. I made sure the input buffer is valid and packet descriptions are provided. I searched and found that a few others have had the same problem: http://lists.apple.com/archives/Coreaudio-api/2008/Jul/msg00119.html Also, the inTimestamp argument doesn't make sense to me. Why should the renderer care where in the audio the beginning of the buffer corresponds to? The function throws an error if I pass in NULL, so I pass in the timestamp anyway.

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  • Calculation of charged traffic in GPRS network

    - by TyBoer
    I am working with a distributed application communicating over GPRS. I use UDP packets to send business data and ICMP pings to verify connectivity. And now I have a problem with calculating a traffic for which I will be charged by the provider. I have to consider following factors: UDP payload: that is obvious. UDP overhead: UDP header + IP header = 8 + 20 bytes. ICMP echo request without data: IP header + ICMP payload = 28 bytes. ICMP echo reply: as in 3. Above means that for evey data packet I am charged for payload + 28 bytes and for every ping 56 bytes. Am I right or I am missing/misunderstanding something?

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  • How do the routers communicate with each other ?

    - by Berkay
    Let's say that i want make a request a to a web page which is hosted in Europe (i live in USA).My packets only consist the IP address of the web page, first the domain name to ip address transformation is done, then my packets start their journey through to europe. i assume that MAC addresses never used in this situation? are they? First, my packets deal with many routers on way how these routers communicate with each other?, are router addresses added to my packet headers ? Second, is there a specific path router to router comminication or which conditions affect this route? Third to cross the Atlantic Ocean, are cables used or... ?

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  • Catch database exception in Kohana

    - by danilo
    I'm using Kohana 2. I would like to catch a database exception to prevent an error page when no connection to the server can be established. The error displayed is system/libraries/drivers/Database/Mysql.php [61]: mysql_connect() [function.mysql-connect]: Lost connection to MySQL server at 'reading initial communication packet', system error: 110 The database server is not reachable at all at this point. I'm doing this from a model. I tried both public function __construct() { // load database library into $this->db try { parent::__construct(); } catch (Exception $e) { die('Database error occured'); } } as well as try { $hoststatus = $this->db->query('SELECT x FROM y WHERE z;'); } catch (Exception $e) { die('Database error occured'); } ...but none of them seemed to work. It seems as if no exception gets passed on from the main model. Is there another way to catch the database error and use my own error handling?

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  • Flash, parameters, security

    - by Quandary
    Hi, I have a question: In Flash, I have the ability to save certain info onto the server. Now the problem is the user needs to be authenticated as admin in order to do so. I can't use sessions, since if you work longer than 20 minutes in the Flash application, the session is gone. The way I see it, I have 2 possibilities: 1. passing a parameter (bIsAdmin) to Flash from the Website. 2. Launch a http-get request, to get this value (bIsAdmin) from an ashx handler on application startup, when the session has not yet exired. In my opinion, both possibilities are not really secure... So, Which one is safer, 1 or 2? Or does anybody have a better idea ? In my opinion, 1 is safer, because with 2, you can just switch a packet tamperer in between, and bang, you're admin, with permission to save (or overwrite, =delete) anything.

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  • Efficient JSON encoding for data that may be binary, but is often text

    - by Evgeny
    I need to send a JSON packet across the wire with the contents of an arbitrary file. This may be a binary file (like a ZIP file), but most often it will be plain ASCII text. I'm currently using base64 encoding, which handles all files, but it increases the size of the data significantly - even if the file is ASCII to begin with. Is there a more efficient way I can encode the data, other than manually checking for any non-ASCII characters and then deciding whether or not to base64-encode it? I'm currently writing this in Python, but will probably need to do the same in Java, C# and C++, so an easily portable solution would be preferable.

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  • Find element with attribute with minidom

    - by Xster
    Given <field name="frame.time_delta_displayed" showname="Time delta from previous displayed frame: 0.000008000 seconds" size="0" pos="0" show="0.000008000"/> <field name="frame.time_relative" showname="Time since reference or first frame: 0.000008000 seconds" size="0" pos="0" show="0.000008000"/> <field name="frame.number" showname="Frame Number: 2" size="0" pos="0" show="2"/> <field name="frame.pkt_len" showname="Packet Length: 1506 bytes" hide="yes" size="0" pos="0" show="1506"/> <field name="frame.len" showname="Frame Length: 1506 bytes" size="0" pos="0" show="1506"/> <field name="frame.cap_len" showname="Capture Length: 1506 bytes" size="0" pos="0" show="1506"/> <field name="frame.marked" showname="Frame is marked: False" size="0" pos="0" show="0"/> <field name="frame.protocols" showname="Protocols in frame: eth:ip:tcp:http:data" size="0" pos="0" show="eth:ip:tcp:http:data"/> How do I get the field with name="frame.len" right away without iterating through every tag and checking the attributes?

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  • Reverse engineering windows mobile live search CellID location awareness protocol (yikes)...

    - by Jean-Charles
    I wasn't sure of how to form the question so I apologize if the title is misleading. Additionally, you may want to get some coffee and take a seat for this one ... It's long. Basically, I'm trying to reverse engineer the protocol used by the Windows Mobile Live Search application to get location based on cellID. Before I go on, I am aware of other open source services (such as OpenCellID) but this is more for the sake of education and a bit for redundancy. According to the packets I captured, a POST request is made to ... mobile.search.live.com/positionlookupservice_1/service.aspx ... with a few specific headers (agent, content-length, etc) and no body. Once this goes through, the server sends back a 100-Continue response. At this point, the application submits this data (I chopped off the packet header): 00 00 00 01 00 00 00 05 55 54 ........UT 46 2d 38 05 65 6e 2d 55 53 05 65 6e 2d 55 53 01 F-8.en-US.en-US. 06 44 65 76 69 63 65 05 64 75 6d 6d 79 01 06 02 .Device.dummy... 50 4c 08 0e 52 65 76 65 72 73 65 47 65 6f 63 6f PL..ReverseGeoco 64 65 01 07 0b 47 50 53 43 68 69 70 49 6e 66 6f de...GPSChipInfo 01 20 06 09 43 65 6c 6c 54 6f 77 65 72 06 03 43 . ..CellTower..C 47 49 08 03 4d 43 43 b6 02 07 03 4d 4e 43 03 34 GI..MCC....MNC.4 31 30 08 03 4c 41 43 cf 36 08 02 43 49 fd 01 00 10..LAC.6..CI... 00 00 00 ... And receives this in response (packet and HTTP response headers chopped): 00 00 00 01 00 00 00 00 01 06 02 50 4c ...........PL 06 08 4c 6f 63 61 6c 69 74 79 06 08 4c 6f 63 61 ..Locality..Loca 74 69 6f 6e 07 03 4c 61 74 09 34 32 2e 33 37 35 tion..Lat.42.375 36 32 31 07 04 4c 6f 6e 67 0a 2d 37 31 2e 31 35 621..Long.-71.15 38 39 33 38 00 07 06 52 61 64 69 75 73 09 32 30 8938...Radius.20 30 30 2e 30 30 30 30 00 42 07 0c 4c 6f 63 61 6c 00.0000.B..Local 69 74 79 4e 61 6d 65 09 57 61 74 65 72 74 6f 77 ityName.Watertow 6e 07 16 41 64 6d 69 6e 69 73 74 72 61 74 69 76 n..Administrativ 65 41 72 65 61 4e 61 6d 65 0d 4d 61 73 73 61 63 eAreaName.Massac 68 75 73 65 74 74 73 07 10 50 6f 73 74 61 6c 43 husetts..PostalC 6f 64 65 4e 75 6d 62 65 72 05 30 32 34 37 32 07 odeNumber.02472. 0b 43 6f 75 6e 74 72 79 4e 61 6d 65 0d 55 6e 69 .CountryName.Uni 74 65 64 20 53 74 61 74 65 73 00 00 00 ted States... Now, here is what I've determined so far: All strings are prepended with one byte that is the decimal equivalent of their length. There seem to be three different casts that are used throughout the request and response. They show up as one byte before the length byte. I've concluded that the three types map out as follows: 0x06 - parent element (subsequent values are children, closed with 0x00) 0x07 - string 0x08 - int? Based on these determinations, here is what the request and response look like in a more readable manner (values surrounded by brackets denote length and values surrounded by parenthesis denote a cast): \0x00\0x00\0x00\0x01\0x00\0x00\0x00 [5]UTF-8 [5]en-US [5]en-US \0x01 [6]Device [5]dummy \0x01 (6)[2]PL (8)[14]ReverseGeocode\0x01 (7)[11]GPSChipInfo[1]\0x20 (6)[9]CellTower (6)[3]CGI (8)[3]MCC\0xB6\0x02 //310 (7)[3]MNC[3]410 //410 (8)[3]LAC\0xCF\0x36 //6991 (8)[2]CI\0xFD\0x01 //259 \0x00 \0x00 \0x00 \0x00 and.. \0x00\0x00\0x00\0x01\0x00\0x00\0x00 \0x00\0x01 (6)[2]PL (6)[8]Locality (6)[8]Location (7)[3]Lat[9]42.375621 (7)[4]Long[10]-71.158938 \0x00 (7)[6]Radius[9]2000.0000 \0x00 \0x42 //"B" ... Has to do with GSM (7)[12]LocalityName[9]Watertown (7)[22]AdministrativeAreaName[13]Massachusetts (7)[16]PostalCodeNumber[5]02472 (7)[11]CountryName[13]United States \0x00 \0x00\0x00 My analysis seems to work out pretty well except for a few things: The 0x01s throughout confuse me ... At first I thought they were some sort of base level element terminators but I'm not certain. I'm not sure the 7-byte header is, in fact, a seven byte header. I wonder if it's maybe 4 bytes and that the three remaining 0x00s are of some other significance. The trailing 0x00s. Why is it that there is only one on the request but two on the response? The type 8 cast mentioned above ... I can't seem to figure out how those values are being encoded. I added comments to those lines with what the values should correspond to. Any advice on these four points will be greatly appreciated. And yes, these packets were captured in Watertown, MA. :)

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  • DIRECTOR "TCP/IP Socket sever/client"

    - by VideoDnd
    Would Director be an option for creating a socket client? My client needs to accept server commands; frame rate, start etc. Director seems like it was made for controlling movies. I've got Director 11.5 at the office. Any lingo experts that could advise? Please post examples if you have any. I'm fed up with Flex and as3 at the moment. SERVER==XML PACKET==CLIENT==swf plays on given frame and duration

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  • Raw socket sendto() failure in OS X

    - by user37278
    When I open a raw socket is OS X, construct my own udp packet (headers and data), and call sendto(), I get the error "Invalid Argument". Here is a sample program "rawudp.c" from the web site http://www.tenouk.com/Module43a.html that demonstrates this problem. The program (after adding string and stdlib #includes) runs under Fedora 10 but fails with "Invalid Argument" under OS X. Can anyone suggest why this fails in OS X? I have looked and looked and looked at the sendto() call, but all the parameters look good. I'm running the code as root, etc. Is there perhaps a kernel setting that prevents even uid 0 executables from sending packets through raw sockets in OS X Snow Leopard? Thanks.

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  • Ipad, closed environment and threat to privacy

    - by Akshay Bhat
    I had an unusual question about ipad, Since ipad environment is closed and does not allows installation of diagnostic and security related programs. How can then we be sure that any of the software installed on ipad is not infringing upon our privacy by doing stuff such as homing back information, etc. We cant install a packet tracer or any other software to check for attacks on privacy. Also given Apples poor track record (the safari browser was broken in one day), I don't think trusting apple solely would be a good idea. This might not seem to be a big issue but for business users it would be a significant concern.

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  • Can Java ServerSocket and Sockets using ObjectIOStreams lose packets?

    - by Joel Garboden
    I'm using a ServerSocket on my server and Sockets that use ObjectIOStreams to send serializable objects over the network connection. I'm developing an essentially more financial version of monopoly and thus packets being sent and confirmed as sent/received is required. Do I need to implement my own packet loss watcher or is that already taken care of with (Server)Sockets? I'm primarily asking about losing packets during network blips or whatnot, not full connection error. E.g. siblings move a lead plate between my router and computer's wi-fi adapter. http://code.google.com/p/inequity/source/browse/#svn/trunk/src/network Code can be found under network-ClientController and network-Server

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  • how to handle CONNECT http request

    - by davidshen84
    hi, i want to implement a simple web server for my self. i can handle GET and POST request now. but i have no idea what to do with CONNECT request. CONNECT request is send when the client is going to access a https site. according to http://muffin.doit.org/docs/rfc/tunneling_ssl.html, it says i should response '200 Connection established'. but i got 'A TLS packet with unexpected length was received' on the client. the wiki described about the ssl handshake protocol, but it did not mention how to implement it.

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  • Prevent users from being able to access a webpage via web browser?

    - by Rob
    My friend and I are working on a program. This program is going to submit GET data to our webpage. However, we don't want users accessing the webpage any other way than the program. We can prevent users from sharing the program using HWID authentication, but nothing prevents them from using a packet scanner to get the URL of the webpage. We thought about user-agent authentication, which we will implement, but user-agents can easily be spoofed. So my question is, how can we prevent users from accessing the webpage directly, instead of through the program? Even if you don't have an answer that will completely work, anything that will help deter them would be nice. Currently we will be implementing: HWID Authentication to use the program User-Agent Authentication to access the web page Instant IP Blacklisting to anyone accessing the webpage without the proper User-Agent

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  • How to pass data to another droid device when the other device isn't expecting it

    - by James Black
    I am working on an application and one feature that would make it really useful is the ability to share some information, but the other device may not be expecting the data to be sent. For example, if I am reading a really good book, and I realize that a friend may like it, I could use an application to send the data to him, so he could order the book from Amazon. But, since he isn't expecting the data, I would hate for the application to be polling a server every so often, as that will be needlessly draining the battery. Ideally it would be great if there was a way to make a phone call to the target device, send a data packet and end the call. If it could be done and prevent the phone from ringing, then it would be very useful to me. I am curious if there is some way to send data between devices without polling.

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  • Java Socket fails to transmit data over the network

    - by Mark Griffin
    I'm experiencing a bizarre problem with sockets between a Java Knopflerfish client bundle and a PHP (CLI, not web) server. The client/server pair work fine when both are located on the localhost, and all data is transmitted successfully. However, when the Java client exists on a different machine, connections to the server are successful, but no data is received by the PHP script. Packet analysis confirms that the data sent by the Java client is received on by the server - PHP just seems to have problems getting its hands on it. As a further note, I've done some tests with telnet as the client. The PHP server script receives all data fine from any host. This leads me to believe that the problem has something to do with the way java is setting up the socket or that there is some networking issue that I'm not familiar with. Any thoughts would be appreciated. Can post code samples if desired.

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