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  • Receving multiple multicast feeds on the same port - C, Linux

    - by Gigi
    I have an application that is receiving data from multiple multicast sources on the same port. I am able to receive the data. However, I am trying to account for statistics of each group (i.e. msgs received, bytes received) and all the data is getting mixed up. Does anyone know how to solved this problem? If I try to look at the sender's address, it is not the multicast address, but rather the IP of the sending machine. I am using the following socket options: struct ip_mreq mreq; mreq.imr_multiaddr.s_addr = inet_addr("224.1.2.3"); mreq.imr_interface.s_addr = INADDR_ANY; setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); and also: setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &reuse, sizeof(reuse)); I appreciate any help!!!

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  • How can I obtain the local TCP port and IP Address of my client program?

    - by Dr Dork
    Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain the local IP address and dynamically assigned TCP port of the client. The function I've found to do this is getsockname()... //setup the socket if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("client: socket"); continue; } //Retrieve the locally-bound name of the specified socket and store it in the sockaddr structure sa_len = sizeof(sa); getsock_check = getsockname(sockfd,(struct sockaddr *)&sa,(socklen_t *)&sa_len) ; if (getsock_check== -1) { perror("getsockname"); exit(1); } printf("Local IP address is: %s\n", inet_ntoa(sa.sin_addr)); printf("Local port is: %d\n", (int) ntohs(sa.sin_port)); but the output is always zero... Local IP address is: 0.0.0.0 Local port is: 0 does anyone see anything I might be or am definitely doing wrong? Thanks so much in advance for all your help!

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  • Transferring Data Directly between 2 Connections in Indy (TIdContext)

    - by killercode
    ive a sever running TIdTCPServer, and Client Using Web Browser (or any other software) to Communicate, i dunno the protocol, but what im trying to do is to Send The Data between the client and another Connection (Both Connected to the same TIdTCPServer) for example the data sent by the first client is transmitted to the second client, and the data sent by the second client is transmitted to the first client, like a proxy (i cant really use a proxy server since its just this one condition) and the TIdTCPServer should still be receiving other clients and processing their data. i stumbled upon the first line of code, since TIdContext.Connection.Socket.ReadLn requires a Delimiter, and the Client's Protocol is unknown to the server. any ideas? thanks.

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  • Sending http headers with python

    - by Niklas R
    I've set up a little script that should feed a client with html. import socket sock = socket.socket() sock.bind(('', 8080)) sock.listen(5) client, adress = sock.accept() print "Incoming:", adress print client.recv(1024) print client.send("Content-Type: text/html\n\n") client.send('<html><body></body></html>') print "Answering ..." print "Finished." import os os.system("pause") But it is shown as plain text in the browser. Can you please tell what I need to do ? I just can't find something in google that helps me.. Thanks.

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  • How to recive more than 65000 bytes in C++ socket using recv()

    - by Mr.Cool
    I am developing a client server application (TCP) in Linux using C++. I want to send more than 65,000 bytes at the same time. In TCP, the maximum packet size is 65,635 bytes only. How can I send the entire bytes without loss? Following is my code at server side. //Receive the message from client socket if((iByteCount = recv(GetSocketId(), buffer, MAXRECV, MSG_WAITALL)) > 0) { printf("\n Received bytes %d\n", iByteCount); SetReceivedMessage(buffer); return LS_RESULT_OK; } If I use MSG_WAITALL it takes a long time to receive the bytes so how can I set the flag to receive more than 10 lakhs bytes at time.

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  • Python 3.3 Webserver restarting problems

    - by IPDGino
    I have made a simple webserver in python, and had some problems with it before as described here: Python (3.3) Webserver script with an interesting error In that question, the answer was to use a While True: loop so that any crashes or errors would be resolved instantly, because it would just start itself again. I've used this for a while, and still want to make the server restart itself every few minutes, but on Linux for some reason it won't work for me. On windows the code below works fine, but on linux it keeps saying Handler class up here ... ... class Server: def __init__(self): self.server_class = HTTPServer self.server_adress = ('MY IP GOES HERE, or localhost', 8080) global httpd httpd = self.server_class(self.server_adress, Handler) self.main() def main(self): if count > 1: global SERVER_UP_SINCE HOUR_CHECK = int(((count - 1) * RESTART_INTERVAL) / 60) SERVER_UPTIME = str(HOUR_CHECK) + " MINUTES" if HOUR_CHECK > 60: minutes = int(HOUR_CHECK % 60) hours = int(HOUR_CHECK // 60) SERVER_UPTIME = ("%s HOURS, %s MINUTES" % (str(hours), str(minutes))) SERVING_ON_ADDR = self.server_adress SERVER_UP_SINCE = str(SERVER_UP_SINCE) SERVER_RESTART_NUMBER = count - 1 print(""" SERVER INFO ------------------------------------- SERVER_UPTIME: %s SERVER_UP_SINCE: %s TOTAL_FILES_SERVED: %d SERVING_ON_ADDR: %s SERVER_RESTART_NUMBER: %s \n\nSERVER HAS RESTARTED """ % (SERVER_UPTIME, SERVER_UP_SINCE, TOTAL_FILES, SERVING_ON_ADDR, SERVER_RESTART_NUMBER)) else: print("SERVER_BOOT=1\nSERVER_ONLINE=TRUE\nRESTART_LOOP=TRUE\nSERVING_ON_ADDR:%s" % str(self.server_adress)) while True: try: httpd.serve_forever() except KeyboardInterrupt: print("Shutting down...") break httpd.shutdown() httpd.socket.close() raise(SystemExit) return def server_restart(): """If you want the restart timer to be longer, replace the number after the RESTART_INTERVAL variable""" global RESTART_INTERVAL RESTART_INTERVAL = 10 threading.Timer(RESTART_INTERVAL, server_restart).start() global count count = count + 1 instance = Server() if __name__ == "__main__": global SERVER_UP_SINCE SERVER_UP_SINCE = strftime("%d-%m-%Y %H:%M:%S", gmtime()) server_restart() Basically, I make a thread to restart it every 10 seconds (For testing purposes) and start the server. After ten seconds it will say File "/home/username/Desktop/Webserver/server.py", line 199, in __init__ httpd = self.server_class(self.server_adress, Handler) File "/usr/lib/python3.3/socketserver.py", line 430, in __init__ self.server_bind() File "/usr/lib/python3.3/http/server.py", line 135, in server_bind socketserver.TCPServer.server_bind(self) File "/usr/lib/python3.3/socketserver.py", line 441, in server_bind self.socket.bind(self.server_address) OSError: [Errno 98] Address already in use As you can see in the except KeyboardInterruption line, I tried everything to make the server stop, and the program stop, but it will NOT stop. But the thing I really want to know is how to make this server able to restart, without giving some wonky errors.

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  • Socket.Recieve Failing When Multithreaded

    - by Qua
    The following piece of code runs fine when parallelized to 4-5 threads, but starts to fail as the number of threads increase somewhere beyond 10 concurrentthreads int totalRecieved = 0; int recieved; StringBuilder contentSB = new StringBuilder(4000); while ((recieved = socket.Receive(buffer, SocketFlags.None)) > 0) { contentSB.Append(Encoding.ASCII.GetString(buffer, 0, recieved)); totalRecieved += recieved; } The Recieve method returns with zero bytes read, and if I continue calling the recieve method then I eventually get a 'An established connection was aborted by the software in your host machine'-exception. So I'm assuming that the host actually sent data and then closed the connection, but for some reason I never recieved it. I'm curious as to why this problem arises when there are a lot of threads. I'm thinking it must have something to do with the fact that each thread doesn't get as much execution time and therefore there are some idle time for the threads which causes this error. Just can't figure out why idle time would cause the socket not to recieve any data.

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  • Problem with close socket

    - by zp26
    Hi, I have a problem with my socket program. I create the client program (my code is below) I have a problem when i close the socket with the disconnect method. Can i help me? Thanks and sorry for my English XP CFSocketRef s; -(void)CreaConnessione { CFSocketError errore; struct sockaddr_in sin; CFDataRef address; CFRunLoopSourceRef source; CFSocketContext context = { 0, self, NULL, NULL, NULL }; s = CFSocketCreate( NULL, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketDataCallBack, AcceptDataCallback, &context); memset(&sin, 0, sizeof(sin)); int port = [fieldPorta.text intValue]; NSString *tempIp = fieldIndirizzo.text; const char *ip = [tempIp UTF8String]; sin.sin_family = AF_INET; sin.sin_port = htons(port); sin.sin_addr.s_addr = (long)inet_addr(ip); address = CFDataCreate(NULL, (UInt8 *)&sin, sizeof(sin)); errore = CFSocketConnectToAddress(s, address, 0); if(errore == 0){ buttonInvioMess.enabled = TRUE; fieldMessaggioInvio.enabled = TRUE; labelTemp.text = [NSString stringWithFormat:@"Connesso al Server"]; CFRelease(address); source = CFSocketCreateRunLoopSource(NULL, s, 0); CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopDefaultMode); CFRelease(source); CFRunLoopRun(); } else{ labelTemp.text = [NSString stringWithFormat:@"Errore di connessione. Verificare Ip e Porta"]; switchConnection.on = FALSE; } } //the socket doesn't disconnect -(void)Disconnetti{ CFSocketInvalidate(s); CFRelease(s); } -(IBAction)Connetti { if(switchConnection.on) [self CreaConnessione]; else [self Disconnetti]; }

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  • python sending incomplete data over socket

    - by tipu
    I have this socket server script, import SocketServer import shelve import zlib class MyTCPHandler(SocketServer.BaseRequestHandler): def handle(self): self.words = shelve.open('/home/tipu/Dropbox/dev/workspace/search/words.db', 'r'); self.tweets = shelve.open('/home/tipu/Dropbox/dev/workspace/search/tweets.db', 'r'); param = self.request.recv(1024).strip() try: result = str(self.words[param]) except KeyError: result = "set()" self.request.send(str(result)) if __name__ == "__main__": HOST, PORT = "localhost", 50007 SocketServer.TCPServer.allow_reuse_address = True server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler) server.serve_forever() And this receiver, from django.http import HttpResponse from django.template import Context, loader import shelve import zlib import socket def index(req, param = ''): HOST = 'localhost' PORT = 50007 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((HOST, PORT)) s.send(param) data = zlib.decompress(s.recv(131072)) s.close() print 'Received', repr(data) t = loader.get_template('index.html') c = Context({ 'foo' : data }) return HttpResponse(t.render(c)) I am sending strings to the receiver that are in the hundreds of kilobytes. I end up only receiving a portion of it. Is there a way that I can fix that so that the whole string is sent?

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  • Perl MiniWebserver

    - by snikolov
    hey guys i have config this miniwebserver, however i require the server to download a file in the local directory i am getting a problem can you please fix my issue thanks !/usr/bin/perl use strict; use Socket; use IO::Socket; my $buffer; my $file; my $length; my $output; Simple web server in Perl Serves out .html files, echos form data sub parse_form { my $data = $_[0]; my %data; foreach (split /&/, $data) { my ($key, $val) = split /=/; $val =~ s/+/ /g; $val =~ s/%(..)/chr(hex($1))/eg; $data{$key} = $val;} return %data; } Setup and create socket my $port = shift; defined($port) or die "Usage: $0 portno\n"; my $DOCUMENT_ROOT = $ENV{'HOME'} . "public"; my $server = new IO::Socket::INET(Proto = 'tcp', LocalPort = $port, Listen = SOMAXCONN, Reuse = 1); $server or die "Unable to create server socket: $!" ; Await requests and handle them as they arrive while (my $client = $server-accept()) { $client-autoflush(1); my %request = (); my %data; { -------- Read Request --------------- local $/ = Socket::CRLF; while (<$client>) { chomp; # Main http request if (/\s*(\w+)\s*([^\s]+)\s*HTTP\/(\d.\d)/) { $request{METHOD} = uc $1; $request{URL} = $2; $request{HTTP_VERSION} = $3; } # Standard headers elsif (/:/) { (my $type, my $val) = split /:/, $_, 2; $type =~ s/^\s+//; foreach ($type, $val) { s/^\s+//; s/\s+$//; } $request{lc $type} = $val; } # POST data elsif (/^$/) { read($client, $request{CONTENT}, $request{'content-length'}) if defined $request{'content-length'}; last; } } } -------- SORT OUT METHOD --------------- if ($request{METHOD} eq 'GET') { if ($request{URL} =~ /(.*)\?(.*)/) { $request{URL} = $1; $request{CONTENT} = $2; %data = parse_form($request{CONTENT}); } else { %data = (); } $data{"_method"} = "GET"; } elsif ($request{METHOD} eq 'POST') { %data = parse_form($request{CONTENT}); $data{"_method"} = "POST"; } else { $data{"_method"} = "ERROR"; } ------- Serve file ---------------------- my $localfile = $DOCUMENT_ROOT.$request{URL}; Send Response if (open(FILE, "<$localfile")) { print $client "HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: text/html", Socket::CRLF; print $client Socket::CRLF; my $buffer; while (read(FILE, $buffer, 4096)) { print $client $buffer; } $data{"_status"} = "200"; } else { $file = 'a.pl'; open(INFILE, $file); while (<INFILE>) { $output .= $_; ##output of the file } $length = length($output); print $client "'HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: application/octet-stream", Socket::CRLF; print $client "Content-Length:".$length, Socket::CRLF; print $client "Accept-Ranges: bytes", Socket::CRLF; print $client 'Content-Disposition: attachment; filename="test.zip"', Socket::CRLF; print $client $output, Socket::CRLF; print $client 'Content-Transfer-Encoding: binary"', Socket::CRLF; print $client "Connection: Keep-Alive", Socket::CRLF; # #$data{"_status"} = "404"; # } close(FILE); Log Request print ($DOCUMENT_ROOT.$request{URL},"\n"); foreach (keys(%data)) { print (" $_ = $data{$_}\n"); } ----------- Close Connection and loop ------------------ close $client; } END

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  • method to find my UDP socket's "real" port?

    - by yairchu
    Is there any free service to which I could send a UDP packet and it would respond telling me what is my "real" UDP port? (my application is behind a NAT) This kind of service could allow me to make a p2p coordination server with normal php hosting. The p2p clients would know their UDP ports from this service They will then contact my server over HTTP (which is what regular web hosting allows) and tell it their port (and ip, which is normally supplied to cgi scripts) My server will give the clients the IP addresses and ports of the other clients.

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  • Need Help finding an appropriate task asignment algoritm for a collage project involving coordinatin

    - by Trif Mircea
    Hello. I am a long time lurker here and have found over time many answers regarding jquery and web development topics so I decided to ask a question of my own. This time I have to create a c++ project for collage which should help manage the workflow of a company providing all kinds of services through in the field teams. The ideas I have so far are: client-server application; the server is a dispatcher where all the orders from clients get and the clients are mobile devices (PDAs) each team in the field having one a order from a client is a task. Each task is made up of a series of subtasks. You have a database with estimations on how long a task should take to complete you also know what tasks or subtasks each team on the field can perform based on what kind of specialists made up the team (not going to complicate the problem by adding needed materials, it is considered that if a member of a team can perform a subtask he has the stuff needed) Now knowing these factors, what would a good task assignment algorithm be? The criteria is: how many tasks can a team do, how many tasks they have in the queue, it could also be location, how far away are they from the place but I don't think I can implement that.. It needs to be efficient and also to adapt quickly is the human dispatcher manually assigns a task. Any help or leads would be really appreciated. Also I'm not 100% sure in the idea so if you have another way you would go about creating such an application please share, even if it just a quick outline. I have to write a theoretical part too so even if the ideas are far more complex that what i outlined that would be ok ; I'd write those and implement what I can.

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  • How to change internal buffer size of DataInputStream

    - by Gaks
    I'm using this kind of code for my TCP/IP connection: sock = new Socket(host, port); sock.setKeepAlive(true); din = new DataInputStream(sock.getInputStream()); dout = new DataOutputStream(sock.getOutputStream()); Then, in separate thread I'm checking din.available() bytes to see if there are some incoming packets to read. The problem is, that if a packet bigger than 2048 bytes arrives, the din.available() returns 2048 anyway. Just like there was a 2048 internal buffer. I can't read those 2048 bytes when I know it's not the full packet my application is waiting for. If I don't read it however - it'll all stuck at 2048 bytes and never receive more. Can I enlarge the buffer size of DataInputStream somehow? Socket receive buffer is 16384 as returned by sock.getReceiveBufferSize() so it's not the socket limiting me to 2048 bytes. If there is no way to increase the DataInputStream buffer size - I guess the only way is to declare my own buffer and read everything from DataInputStream to that buffer? Regards

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  • Silverlight 4 IN Browser Socket

    - by Benny
    I need to use a TCP socket connecting to a port outside of 4502-4532 while running in browser. I know it is possible to do out of browser with allowing full access, but how can I do it inside the browser? I am connecting to an old Unix system so I would prefer not to host a web site hosting a clientaccesspolicy.xml file. Thanks in advance!

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  • How to use data receive event in Socket class?

    - by affan
    I have wrote a simple client that use TcpClient in dotnet to communicate. In order to wait for data messages from server i use a Read() thread that use blocking Read() call on socket. When i receive something i have to generate various events. These event occur in the worker thread and thus you cannot update a UI from it directly. Invoke() can be use but for end developer its difficult as my SDK would be use by users who may not use UI at all or use Presentation Framework. Presentation framework have different way of handling this. Invoke() on our test app as Microstation Addin take a lot of time at the moment. Microstation is single threaded application and call invoke on its thread is not good as it is always busy doing drawing and other stuff message take too long to process. I want my events to generate in same thread as UI so user donot have to go through the Dispatcher or Invoke. Now i want to know how can i be notified by socket when data arrive? Is there a build in callback for that. I like winsock style receive event without use of separate read thread. I also do not want to use window timer to for polling for data. I found IOControlCode.AsyncIO flag in IOControl() function which help says Enable notification for when data is waiting to be received. This value is equal to the Winsock 2 FIOASYNC constant. I could not found any example on how to use it to get notification. If i am write in MFC/Winsock we have to create a window of size(0,0) which was just used for listening for the data receive event or other socket events. But i don't know how to do that in dotnet application.

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  • Reply to specific socket client.

    - by David
    hi, I am using C#. I have one socket server in PC A and three socket clients in PC B,PC C,and PC D.When PC A receives data, I want to send this data to either PC B or PC C or PC D. I mean i don't want to send this data to all PC.I just want to send the PC i need to send. Now, when server receives data from one client PC, it sends back to all clients PC. Thank you.

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  • Comparing a peer's IPv6 address with localhost

    - by indiv
    I have called getpeername on my connected socket and now have an IPv6 address of the connected peer. How do I tell whether my peer's IP address is localhost? (the host name "localhost" is not defined in the target system's hosts file, so I need to work with IP addresses only)

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  • Object Oriented Perl interface to read from and write to a socket

    - by user654967
    I need a perl client-server implementation as a wrapper for a server in C#. A perl script passes the server address and port number and an input string to a module, this module has to create the socket and send the input string to the server. The data sent has to follow ISO-8859-1 encoding. On receiving the information, the client has to first receive 3 byte, then the next 8 bytes, this has the length of the data that has to be received next.. so based on the length the client has to read the next data. each of the data that is read has to be stored in a variable and sent another module for further processing. Currently this is what my perl client looks like..which I'm sure isn't right..could someone tell me how to do this..and set me on the right direction.. sub WriteInfo { my ($addr, $port, $Input) = @_; $socket = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $addr, PeerPort => $port, ); unless ($socket) { die "cannot connect to remote" } while (1) { $socket->send($Input); } } sub ReadData { while (1) { my $ExecutionResult = $socket->recv( $recv_data, 3); my $DataLength = $socket->recv( $recv_data, 8); $DataLength =~ s/^0+// ; my $decval = hex($DataLength); my $Data = $socket->recv( $recv_data, $decval); return($Data); } thanks a lot.. Archer

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  • If a nonblocking recv with MSG_PEEK succeeds, will a subsequent recv without MSG_PEEK also succeed?

    - by Michael Wolf
    Here's a simplified version of some code I'm working on: void stuff(int fd) { int ret1, ret2; char buffer[32]; ret1 = recv(fd, buffer, 32, MSG_PEEK | MSG_DONTWAIT); /* Error handling -- and EAGAIN handling -- would go here. Bail if necessary. Otherwise, keep going. */ /* Can this call to recv fail, setting errno to EAGAIN? */ ret2 = recv(fd, buffer, ret1, 0); } If we assume that the first call to recv succeeds, returning a value between 1 and 32, is it safe to assume that the second call will also succeed? Can ret2 ever be less than ret1? In which cases? (For clarity's sake, assume that there are no other error conditions during the second call to recv: that no signal is delivered, that it won't set ENOMEM, etc. Also assume that no other threads will look at fd. I'm on Linux, but MSG_DONTWAIT is, I believe, the only Linux-specific thing here. Assume that the right fnctl was set previously on other platforms.)

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  • Problem about socket communication

    - by Ahmet Altun
    I have two separate socket projects in VS.NET. One of them is sender, other one is receiver. After starting receiver, i send data from sender. Although send method returns 13 bytes as successfully transferred, the receiver receives 0 (zero). The receiver accepts sender socket and listens to it. But cannot receive data. Why? P.S. : If sender code is put in receiver project, receiver can get data, as well.

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  • Java Socks Proxy Socket Error

    - by Ionut Ungureanu
    I am trying to create a http request through a SOCKS (v4 / v5) proxy in Java. After reading about socks communication protocol on WikiPedia, I have put togheter this piece of code: Socket sock = new Socket(); InetSocketAddress remoteProxyAddress = new InetSocketAddress(proxy ip, proxy port); sock.connect(remoteProxyAddress, connTimeout); InputStream in = sock.getInputStream(); OutputStream out = sock.getOutputStream(); out.write(0x04); out.write(0x01); out.write((endpoint.getPort() >> 8) & 0xff); out.write((endpoint.getPort() >> 0) & 0xff); out.write(endpoint.getAddress().getAddress()); out.write(0x0); out.flush(); And here comes the part where I read from the proxy server. The problem is that the response is always "-1". I have tried the proxy on Firefox and it works perfect. So... the problem is in my app. Can anyone help me? Thanks!

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  • Sending buffered images between Java client and Twisted Python socket server

    - by PattimusPrime
    I have a server-side function that draws an image with the Python Imaging Library. The Java client requests an image, which is returned via socket and converted to a BufferedImage. I prefix the data with the size of the image to be sent, followed by a CR. I then read this number of bytes from the socket input stream and attempt to use ImageIO to convert to a BufferedImage. In abbreviated code for the client: public String writeAndReadSocket(String request) { // Write text to the socket BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())); bufferedWriter.write(request); bufferedWriter.flush(); // Read text from the socket BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream())); // Read the prefixed size int size = Integer.parseInt(bufferedReader.readLine()); // Get that many bytes from the stream char[] buf = new char[size]; bufferedReader.read(buf, 0, size); return new String(buf); } public BufferedImage stringToBufferedImage(String imageBytes) { return ImageIO.read(new ByteArrayInputStream(s.getBytes())); } and the server: # Twisted server code here # The analog of the following method is called with the proper client # request and the result is written to the socket. def worker_thread(): img = draw_function() buf = StringIO.StringIO() img.save(buf, format="PNG") img_string = buf.getvalue() return "%i\r%s" % (sys.getsizeof(img_string), img_string) This works for sending and receiving Strings, but image conversion (usually) fails. I'm trying to understand why the images are not being read properly. My best guess is that the client is not reading the proper number of bytes, but I honestly don't know why that would be the case. Side notes: I realize that the char[]-to-String-to-bytes-to-BufferedImage Java logic is roundabout, but reading the bytestream directly produces the same errors. I have a version of this working where the client socket isn't persistent, ie. the request is processed and the connection is dropped. That version works fine, as I don't need to care about the image size, but I want to learn why the proposed approach doesn't work.

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  • Packet fragmentation when sending data via SSLStream

    - by Ive
    When using an SSLStream to send a 'large' chunk of data (1 meg) to a (already authenticated) client, the packet fragmentation / dissasembly I'm seeing is FAR greater than when using a normal NetworkStream. Using an async read on the client (i.e. BeginRead()), the ReadCallback is repeatedly called with exactly the same size chunk of data up until the final packet (the remainder of the data). With the data I'm sending (it's a zip file), the segments happen to be 16363 bytes long. Note: My receive buffer is much bigger than this and changing it's size has no effect I understand that SSL encrypts data in chunks no bigger than 18Kb, but since SSL sits on top of TCP, I wouldn't think that the number of SSL chunks would have any relevance to the TCP packet fragmentation? Essentially, the data is taking about 20 times longer to be fully read by the client than with a standard NetworkStream (both on localhost!) What am I missing? EDIT: I'm beginning to suspect that the receive (or send) buffer size of an SSLStream is limited. Even if I use synchronous reads (i.e. SSLStream.Read()), no more data ever becomes available, regardless of how long I wait before attempting to read. This would be the same behavior as if I were to limit the receive buffer to 16363 bytes. Setting the Underlying NetworkStream's SendBufferSize (on the server), and ReceiveBufferSize (on the client) has no effect.

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  • Sending email to gmail account using c++ on windows error check

    - by LCD Fire
    I know this has been disscused a lot, but I I'm not asking how to do it, I'm just asking why it doesn't work. What I am doing wrong. It says that the email was sent succesfully but I don't see it in my inbox. I want to send an email to a gmail account, not through it. #include <iostream> #include <windows.h> #include <fstream> #include <conio.h> #pragma comment(lib, "ws2_32.lib") // Insist on at least Winsock v1.1 const int VERSION_MAJOR = 1; const int VERSION_MINOR = 1; #define CRLF "\r\n" // carriage-return/line feed pair using namespace std; // Basic error checking for send() and recv() functions void Check(int iStatus, char *szFunction) { if((iStatus != SOCKET_ERROR) && (iStatus)) return; cerr<< "Error during call to " << szFunction << ": " << iStatus << " - " << GetLastError() << endl; } int main(int argc, char *argv[]) { int iProtocolPort = 25; char szSmtpServerName[64] = ""; char szToAddr[64] = ""; char szFromAddr[64] = ""; char szBuffer[4096] = ""; char szLine[255] = ""; char szMsgLine[255] = ""; SOCKET hServer; WSADATA WSData; LPHOSTENT lpHostEntry; LPSERVENT lpServEntry; SOCKADDR_IN SockAddr; // Check for four command-line args //if(argc != 5) // ShowUsage(); // Load command-line args lstrcpy(szSmtpServerName, "smtp.gmail.com"); lstrcpy(szToAddr, "[email protected]"); lstrcpy(szFromAddr, "[email protected]"); // Create input stream for reading email message file ifstream MsgFile("D:\\d.txt"); // Attempt to intialize WinSock (1.1 or later) if(WSAStartup(MAKEWORD(VERSION_MAJOR, VERSION_MINOR), &WSData)) { cout << "Cannot find Winsock v" << VERSION_MAJOR << "." << VERSION_MINOR << " or later!" << endl; return 1; } // Lookup email server's IP address. lpHostEntry = gethostbyname(szSmtpServerName); if(!lpHostEntry) { cout << "Cannot find SMTP mail server " << szSmtpServerName << endl; return 1; } // Create a TCP/IP socket, no specific protocol hServer = socket(PF_INET, SOCK_STREAM, 0); if(hServer == INVALID_SOCKET) { cout << "Cannot open mail server socket" << endl; return 1; } // Get the mail service port lpServEntry = getservbyname("mail", 0); // Use the SMTP default port if no other port is specified if(!lpServEntry) iProtocolPort = htons(IPPORT_SMTP); else iProtocolPort = lpServEntry->s_port; // Setup a Socket Address structure SockAddr.sin_family = AF_INET; SockAddr.sin_port = iProtocolPort; SockAddr.sin_addr = *((LPIN_ADDR)*lpHostEntry->h_addr_list); // Connect the Socket if(connect(hServer, (PSOCKADDR) &SockAddr, sizeof(SockAddr))) { cout << "Error connecting to Server socket" << endl; return 1; } // Receive initial response from SMTP server Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() Reply"); // Send HELO server.com sprintf(szMsgLine, "HELO %s%s", szSmtpServerName, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() HELO"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() HELO"); // Send MAIL FROM: <[email protected]> sprintf(szMsgLine, "MAIL FROM:<%s>%s", szFromAddr, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() MAIL FROM"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() MAIL FROM"); // Send RCPT TO: <[email protected]> sprintf(szMsgLine, "RCPT TO:<%s>%s", szToAddr, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() RCPT TO"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() RCPT TO"); // Send DATA sprintf(szMsgLine, "DATA%s", CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() DATA"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() DATA"); //strat writing about the subject, end it with two CRLF chars and after that you can //write data to the body oif the message sprintf(szMsgLine, "Subject: My own subject %s%s", CRLF, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() DATA"); // Send all lines of message body (using supplied text file) MsgFile.getline(szLine, sizeof(szLine)); // Get first line do // for each line of message text... { sprintf(szMsgLine, "%s%s", szLine, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() message-line"); MsgFile.getline(szLine, sizeof(szLine)); // get next line. } while(!MsgFile.eof()); // Send blank line and a period sprintf(szMsgLine, "%s.%s", CRLF, CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() end-message"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() end-message"); // Send QUIT sprintf(szMsgLine, "QUIT%s", CRLF); Check(send(hServer, szMsgLine, strlen(szMsgLine), 0), "send() QUIT"); Check(recv(hServer, szBuffer, sizeof(szBuffer), 0), "recv() QUIT"); // Report message has been sent cout<< "Sent " << argv[4] << " as email message to " << szToAddr << endl; // Close server socket and prepare to exit. closesocket(hServer); WSACleanup(); _getch(); return 0; }

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  • Connections hanging on read()

    - by viraptor
    Hi, Short version: I've got a strange issue with a server accepting TCP connections. Even though there are normally some processes waiting, at some volume of connections it hangs. Long version: The server is written in Perl and binds a $srv socket with the reuse flag and listen == 5. Afterwards, it forks into 10 processes with a loop of $clt=$srv->accept(); do_processing($clt); $clt->shutdown(2); The client written in C is also very simple - it sends some lines, then receives all lines available and does a shutdown(sockfd, 2); There's nothing async going on and at the end both send and receive queues are empty (as reported by netstat). Connections last only ~20ms. All clients behave the same way, are the same implementation, etc. Now let's say I'm accepting X connections from client 1 and another X from client 2. Processes still report that they're idle all the time. If I add another X connections from client 3, suddenly the server processes start hanging just after accepting. The first blocking thing they do after accept(); is while (<$clt>) ... - but they don't get any data (on the first try already). Suddenly all 10 processes are in this state and do not stop waiting. On strace, the server processes seem to hang on read(), which makes sense. There are loads of connections in TIME_WAIT state belonging to that server (~100 when the problem starts to manifest), but this might be a red herring. What could be happening here?

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