159 lines
4.7 KiB
C
159 lines
4.7 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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/* port we're listening on */
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#define PORT 2020
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int main(int argc, char *argv[])
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{
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/* master file descriptor list */
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fd_set master;
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/* temp file descriptor list for select() */
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fd_set read_fds;
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/* server address */
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struct sockaddr_in serveraddr;
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/* client address */
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struct sockaddr_in clientaddr;
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/* maximum file descriptor number */
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int fdmax;
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/* listening socket descriptor */
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int listener;
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/* newly accept()ed socket descriptor */
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int newfd;
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/* buffer for client data */
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char buf[1024];
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int nbytes;
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/* for setsockopt() SO_REUSEADDR, below */
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int yes = 1;
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int addrlen;
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int i, j;
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/* clear the master and temp sets */
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FD_ZERO(&master);
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FD_ZERO(&read_fds);
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/* get the listener */
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if((listener = socket(AF_INET, SOCK_STREAM, 0)) == -1)
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{
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perror("Server-socket() error lol!");
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exit(1);
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}
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printf("Server-socket() is OK...\n");
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/*"address already in use" error message */
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if(setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1)
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{
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perror("Server-setsockopt() error lol!");
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exit(1);
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}
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printf("Server-setsockopt() is OK...\n");
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/* bind */
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serveraddr.sin_family = AF_INET;
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serveraddr.sin_addr.s_addr = INADDR_ANY;
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serveraddr.sin_port = htons(PORT);
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memset(&(serveraddr.sin_zero), '\0', 8);
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if(bind(listener, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) == -1)
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{
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perror("Server-bind() error lol!");
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exit(1);
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}
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printf("Server-bind() is OK...\n");
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/* listen */
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if(listen(listener, 10) == -1)
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{
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perror("Server-listen() error lol!");
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exit(1);
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}
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printf("Server-listen() is OK...\n");
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/* add the listener to the master set */
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FD_SET(listener, &master);
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/* keep track of the biggest file descriptor */
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fdmax = listener; /* so far, it's this one*/
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/* loop */
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for(;;) {
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/* copy it */
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read_fds = master;
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if(select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1)
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{
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perror("Server-select() error lol!");
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exit(1);
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}
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printf("Server-select() is OK...\n");
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/*run through the existing connections looking for data to be read*/
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for(i = 0; i <= fdmax; i++) {
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if(FD_ISSET(i, &read_fds)) {
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/* we got one... */
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if(i == listener) {
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/* handle new connections */
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addrlen = sizeof(clientaddr);
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if((newfd = accept(listener, (struct sockaddr *)&clientaddr, &addrlen)) == -1)
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{
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perror("Server-accept() error lol!");
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}
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else
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{
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printf("Server-accept() is OK...\n");
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FD_SET(newfd, &master); /* add to master set */
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if(newfd > fdmax)
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{ /* keep track of the maximum */
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fdmax = newfd;
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}
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printf("%s: New connection from %s on socket %d\n"
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, argv[0], inet_ntoa(clientaddr.sin_addr), newfd);
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}
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}
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else {
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/* handle data from a client */
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if((nbytes = recv(i, buf, sizeof(buf), 0)) <= 0) {
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/* got error or connection closed by client */
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if(nbytes == 0)
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/* connection closed */
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printf("%s: socket %d hung up\n", argv[0], i);
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else
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perror("recv() error lol!");
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/* close it... */
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close(i);
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/* remove from master set */
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FD_CLR(i, &master);
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}
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else {
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/* we got some data from a client*/
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for(j = 0; j <= fdmax; j++) {
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/* send to everyone! */
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if(FD_ISSET(j, &master)) {
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/* except the listener and ourselves */
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if(j != listener && j != i) {
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if(send(j, buf, nbytes, 0) == -1)
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perror("send() error lol!");
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}
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}
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}
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}
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}
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}
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}
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}
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return 0;
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}
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