I have currently had the need to go back to basic socket programming, and implemented a simple udp packet sender. But I realized I needed to be able to select which network interface to send the packets from.
The reason is so that one of the interfaces has vlan tagging, and I need my UDP packets to be accordingly vlan tagged. For example, one of the interfaces is eth1.200.
I'm facing a strange problem with our code. What the program does is to wait on a select() after a non-blocking connect. And I expect the select wake up with write_set after the ESTAB. And I expect select wakeup with both rd_set and wr_set if I recv a RST back for our SYN or any similar errors. But in one of the cases I'm seeing select is waking up with only rd_set in a non-connected sockeet, which is causing a lot of problems for me.
The code is organized such that the socket close() happens only in wr_set processing. Because of that with the above problem I'm going in to a strange scenario. After the event I call select() again and wait for another socket event. But with this issue, my select is waking up there after everytime as soon as I call select(). That too only with rd_set. So it keeps on going with select() sleeping 0 secs. Thus the program is hung and eating lot of CPU cycles also.
The trigger for all these problems seems to be some event which causes the waking up of select() with rd_set only. I tried many ways to find out what is happening with this. Couldn't find anything interesting yet.
iam just trying to connect to server which accepts one client and server will read(blocking operation) infinitely, but After closing the client socket the server "read operation" is returning zero and "errno variable(in errno.h)" value is also zero. how can i detect whether a client socket is closed/active..?
client.c
Serv_Addr.sin_family = AF_INET;
Serv_Addr.sin_addr.s_addr = inet_addr("127.0.0.1");
Serv_Addr.sin_port = htons(26553);
if( 0 > connect (Serv_Fds,&Serv_Addr,sizeof(Serv_Addr)) )
{
perror("connect");
return 0;
[Code]....
I have a server listening on incoming client connections. Once the client establishes SSL connection with the server, the server waits on read() from the client. Only Client can disconnect the connection. I want to have a timer in the server program to wait for x secs after read() and then disconnect the Client connection.
View 3 Replies View Relatedi have a server program which accept multiple client connection and am using polling. like every 2 secs it will look to client whether any data is received after it binded. i have used setitimer but there is runtime error i got.. the server accept all client connection but doesn't execute any msg which client sent.
#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<netdb.h>
#include<unistd.h>
#include<pthread.h>
#include<string.h>
[Code]....
i have problem in socket programming, while displaying received message in file,i got a problem... i cant able to write it in the file.... this is the code....
Code:
/* tcpserver.c */
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
[Code]....
now my problem is run time error i can able to create file but i cant able to write file....log.txt contain nothing.... as here i have give sample code... dont say not initialising function and all.... i have initialised , please only see func1() - my problem is only not able to write msg which i got received from the client..
how to use socket programming in order to implement chatting feature
View 5 Replies View Relatedi'm writing a simple program of client socket program. Here below is the code sample which i'm writing...
Code:
//tcp_client.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include<string.h>
#include<stdlib.h>
[Code].....
the above code works fine.if we copmile and run ./a.exe 192.xx.xx.xxx 1111 and press enter it works fine..everytime it asks "Please enter the message: " and if give that will be displayed in server. but my problem is i dont want to print everytime "Please enter the message: " i just want to feed some words one by one to the socket.
im getting that error in my code for some reason. I compiled my code, and when i try to run this server it throws me an error on my call to setsocketopt(). The only way it can reach that part of my loop is if it succeeds when it calls sock() so I dont understand why the error says its an operation on a non-socket. Im just trying to set up a server to pass messages from a client to it a viceversa. Here is the code:
Code:
int main()
{
int socket_fd, new_socket_fd, k;
struct addrinfo hints, *server_info, *p;
struct sockaddr_storage peer_address;
code....
When sending data over the socket, the sending socket includes 0x00 after each sent byte. I wonder how this can be avoided -- I just want to transfer the data in the tx_buffer as it is.
# ./serv &
[1] 6895
# ./EUG 127.0.0.1
EUG: Data to be transmitted: 0x35 0x32 0x30 0xff 0x03 0x31
EUG: Data - #Bytes transmitted: 6
./serv: Here is the message: '5'
[Code]...
Is it possible to swap a client ip and port ? This is what I am trying to do. Let say you have Comp1 and Comp2 And you have Server between them. My goal is to get Comp1 and Comp2 know each others IP So Comp1 connects to server And server stores comp1's IP In a text file or other place And Comp2 connect to server And server also stores his info And then both comp1 and comp2 dowload the tex file And use the info on it.
View 9 Replies View RelatedHow can we build a packet using C?we have a structure called sockaddr_in which is use to for IPv4,so that we can define address,port and etc in this way:
Code:
struct sockaddr_in sock;
sock.sin_family=AF_INET;
[code]...
This is my main question:Quote: In raw socket sniffing: how do I copy data from a structure into a char[] or pointer? My problem: I started doing some raw socket programming in OpenWRT (I'm a newbie) for research. It's been a long time since the last time I programmed in C, so here's my newbie question/problem.
I'm receiving packets and using an .h file with the structures to get the information of each 802.11 packet in monitor mode (attached to this post).My (simple) goal is to get the Tx MAC Address. No luck. This is my "read the prism header" function:
Code:
ParsePrismHeader(unsigned char *packet,int len)
{
wlan_header *wlan;ieee_802_11_header *i802;u_int16_t eth_type;
unsigned char *mac;unsigned char *mac2;
wlan = (wlan_header *)packet;
i802 = (ieee_802_11_header *)(packet + wlan->msglen);
[Code]...
I am currently doing a research on video transmission over wireless LAN. I tend to transmit my offline file (xx.svc) from server to client.It may sound stupid (since I have a very little knowledge about c programming and raw socket), but my biggest challenges is that when I want to write the file to the buffer, how actually to define/include the file at the programming coding? where I need to locate the file? Is it at the same folder with my c programming, or somewhere in the linuxinclude folder?
Can anyone just give a simple example on how to include a file and write it into a buffer before send it through raw socket.
I am looking to be able to connect to an IRC server in a C program. I have followed some instructions from an old book I have however it doesn't seem to be working. I've tried connecting to localhost on my ssh port and it still doesn't want to work. This is what I have so far as a piece of skeleton test code:
Code:
#include<sys/types.h>
#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<unistd.h>
#include<netinet/in.h>
#include<arpa/inet.h>
[Code]....
Where is the perl module for programming with sockets?
View 4 Replies View Relatedthis is my client and server. I can receive text file. but I can't send other type of file like PDF,Docx,Odt
View 11 Replies View RelatedHas anyone had an issue with gdb not being able to send a UDP msg across a socket?
I have ComponentA sending a msg to ComponentB utilizing gdb. ComponentB gets the msg. ComponentB sends a msg to ComponentC. ComponentC does stuff to the msg and sends a msg back to ComponentB using gdb.
ComponentB never seems to receive the 2nd message.
If I don't use gdb the messages Tx and Rx without an issue.
I'm flying blind without gdb to figure out a different bug.
How does bind system call names a socket.Code:bind(server_sockfd, (struct sockaddr *)&server_address, server_len);I see use of bind in majority of programms as above.But any of the arguments is not the name of socket.
View 1 Replies View Related(Let me first of all state that I am a newbie to any form of programming.) I have been trying to create an IP header + TCP header and send this to another machine on my network.using C)I used the normal stuff: two structures for the headers, a sockaddr_in structure, call to function socket with SOCK_RAW, setsockopt with HDRINCL and call to sendto.All functions seem to return fine (values other then -1) the function that I have used to calculate the checksum for the IPheader matches the value that I manually calculated. I just don?t see the anything coming out of the interface on whireshark.I assumed that it had something do with my piece of code so I used two examples (including mixter void ru rawip html A brief programming tutorial in C for raw sockets[/url]). They show exactly the same thing functions return fine but no packets being send.I use Ubuntu 9.04 2.6.28-14-genericThe machine has two interfaces one with an ip address the other interface is in promiscuous mode. (both interfaces connected to a switch with port mirroring) I can see all normal traffic in/out.
View 2 Replies View RelatedI am programming an application with an ARM device with an embedded version of Linux. My application talks to a java application via socket. If there is any connection problems, it attempts the connection again. My problem is that after exactly 146 times, there is a Segmentation Fault. Apparently this happens in opening the socket, which is not successful after this amount of attempts.
Following, some code that I'm using:
The function for openning the socket and perform a connection:
Code:
I need to read data from a socket but it should be always listening because data arrives continuously .. I thought something like this would do it but it doesn't work .... I already set the socket options before
Code: char databuf[1024];
int datalen = sizeof(databuf);
if(read(sd, databuf, datalen) < 0)
{
[Code]....
I don't have the IP address & Port of the server but I know the hostname (URL) to establish a connection.How can I use it to get connected to the particular host?
View 4 Replies View RelatedI have scoured google for ways to get the source address of the client sent to my server which receives using UDP sockets.
I get the packet with no issue, but I would like to get the source address. Where it currently uses 192.168.0.103, I would like it to be this address.
Code:
#include "rbsocket.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <errno.h>
[Code].....
Code:
void* thread(void* arg)
{
[code]....
Been trying all sorts of different things to implement a non-blocking send on a TCP server socket.As I kill the client, the server keeps blocking on the send no matter what. Am I missing something? Any other way to do that without involving any additional thread?
View 4 Replies View RelatedLet's show the problem: I have a socked connection (in a fd var). In certain moment, I need to use the same socket in two threads. Lets see in the example:
Code: int main(void)
{
int fd; // the socket
[code]....
I want to built a Chat Program (based on Socket connection) between client and server. I use the GTK+ &GLADE graphic tool. Can you send me the code for this program or any material to learn. Also, I want to know how to show the input to text view (in GTK+&Glade).
View 3 Replies View RelatedI need to make a daemon which listens to port 81 for messages like [URL] So far I made a daemon which serves as a simple stream server: I set up a socket to listen to a non-reserved port (like 9999), but I don't know how to read the query strings.
Linux distro: Kubuntu 9.04
Language: C
I am trying to create a socket server in user space and a client in kernel space and send big messages (a little over 64kbytes) between them.
I used an kernel socket programming examplefrom this link - url for the kernel client side.
When the client in kernel side sends out a 64k message, usually, the server side in the user space will get a big part of the message, but will stuck at waiting for the recv() to return to get the rest of it. So I am chopping the packets into small pieces, 1000 bytes each to send to the server. But only some times, the packets will all arrive at the server/receiver side, and the server and assemble the whole message. Many times, the server is stuck at waiting for the last a couple of byte from the sending side. From the sending side printk log, it has already sent every thing.
I am attaching some log here, and the code at the end. Can someone give me some idea on how to force the data to arrive at the receiver side? Maybe the kernel on the receiver side is holding part of the packet so
the receiver program in the user space is blocked at recv()? I tried adding TCP_NODELAY on sockets on both sender and receiver sides, both it did not help.
I got a connection from (10.16.216.217 , 1489)
- Server side stuck on recv()-
bytes_recieved 17384
bytes_recieved 32768, total received 50152, expected 65540
- Client side is already done -
code....