redirect to a website in c - sockets

Question

I am using the following code to redirect client request. But when doing the following the clients are not redirected. Its showing "Unable to connect" in the browser. I redirect the clients to port 8080 using iptables. And running the following executable to redirect. How to redirect the clients. Please provide solution....
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
#include<stdlib.h>
int main(int argc, char *argv[])
{
int listenfd = 0, connfd = 0;
struct sockaddr_in serv_addr;
char *reply = "HTTP/1.1 301 Moved Permanently\nServer: Apache/2.2.3\nLocation:
http://www.google.com\nContent-Length: 1000\nConnection: close\nContent-Type:
text/html; charset=UTF-8";
char sendBuff[1025];
time_t ticks;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(&serv_addr, '0', sizeof(serv_addr));
memset(sendBuff, '0', sizeof(sendBuff));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(8080);
bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
listen(listenfd, 10);
while(1)
{
connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
printf("client connected\n");
send(connfd, reply, strlen(reply), 0);
close(connfd);
sleep(1);
}
}

Answer 1

Please refer to the example in this page or this page to construct a valid http response on the server side. Then, add your html body below it.
Minimum you would need is
HTTP/1.1 200 OK
Content-Length: XXXXX <- put size of the your html body
Connection: close
Content-Type: text/html; charset=UTF-8

Answer 2

I am unable to reproduce the error that you see. You should provide more details (e.g., what kind of client, exact text of iptables rule). For my test, I did not set any iptables rule, and instead pointed the Firefox 12.0 browser directly to localhost:8080.
Splitting up your reply so that it is easier to read shows:
char *reply =
"HTTP/1.1 301 Moved Permanently\n"
"Server: Apache/2.2.3\n"
"Location: http://www.google.com\n"
"Content-Length: 1000\n"
"Connection: close\n"
"Content-Type: text/html; charset=UTF-8"
;
Although the RFC specifies \r\n for line terminators, most clients will accept \n (you don't say which client you are using). But, three other glaring issues are that the last line is not terminated, the response itself is not terminated by a blank line, and you have a Content-Length header of 1000, but no content. Any of these issues could be cause for a client to treat the response as invalid and ignore it.
char *reply =
"HTTP/1.1 301 Moved Permanently\r\n"
"Server: Apache/2.2.3\r\n"
"Location: http://www.google.com\r\n"
"Content-Length: 0\r\n"
"Connection: close\r\n"
"Content-Type: text/html; charset=UTF-8\r\n"
"\r\n"
;
Reading farther into your code, you close the connection immediately after sending your reply without first reading the request. This might lead to an (albeit unlikely) race where you close the connection before the request is fully delivered to the server. Then, when the request does arrive, it will trigger a reset to the client, and the response could be dropped. So, you should add code to make the delivery of your reply more robust:
printf("client connected\n");
send(connfd, reply, strlen(reply), 0);
shutdown(connfd, SHUT_WR);
while (recv(connfd, sendBuff, sizeof(sendBuff), 0) > 0) {}
close(connfd);
Given that I cannot reproduce your issue with the response as it is, though, it is also possible that you did not set your iptable redirect rule properly.