138 lines
2.7 KiB
C
138 lines
2.7 KiB
C
/* This file is part of the sample code and exercises
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* used by the class "Advanced Programming in the UNIX
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* Environment" taught by Jan Schaumann
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* <jschauma@netmeister.org> at Stevens Institute of
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* Technology.
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*
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* This file is in the public domain.
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*
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* You don't have to, but if you feel like
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* acknowledging where you got this code, you may
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* reference me by name, email address, or point
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* people to the course website:
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* https://stevens.netmeister.org/631/
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*/
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/*
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* This program illustrates the dilemma of handling
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* multiple file descriptors. Compare with
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* two-sockets-select.c to show how I/O multiplexing
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* could be done.
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*/
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#include <arpa/inet.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#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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#define BACKLOG 5
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int
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createSocket(void)
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{
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int sock;
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socklen_t length;
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struct sockaddr_in6 server;
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memset(&server, 0, sizeof(server));
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if ((sock = socket(PF_INET6, SOCK_STREAM, 0)) < 0) {
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perror("opening stream socket");
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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}
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server.sin6_family = PF_INET6;
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server.sin6_addr = in6addr_any;
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server.sin6_port = 0;
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if (bind(sock, (struct sockaddr *)&server, sizeof(server)) != 0) {
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perror("binding stream socket");
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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}
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length = sizeof(server);
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if (getsockname(sock, (struct sockaddr *)&server, &length) != 0) {
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perror("getting socket name");
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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}
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(void)printf("Socket has port #%d\n", ntohs(server.sin6_port));
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if (listen(sock, BACKLOG) < 0) {
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perror("listening");
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exit(EXIT_FAILURE);
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/* NOTREACHED */
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}
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return sock;
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}
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void
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handleSocket(int s)
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{
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int fd, rval;
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char claddr[INET6_ADDRSTRLEN];
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struct sockaddr_in6 client;
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socklen_t length;
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length = sizeof(client);
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memset(&client, 0, length);
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if ((fd = accept(s, (struct sockaddr *)&client, &length)) < 0) {
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perror("accept");
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return;
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}
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do {
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char buf[BUFSIZ];
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bzero(buf, sizeof(buf));
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if ((rval = read(fd, buf, BUFSIZ)) < 0) {
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perror("reading stream message");
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}
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if (rval == 0) {
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(void)printf("Ending connection\n");
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} else {
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const char *rip;
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if ((rip = inet_ntop(PF_INET6, &(client.sin6_addr), claddr, INET6_ADDRSTRLEN)) == NULL) {
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perror("inet_ntop");
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rip = "unknown";
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} else {
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(void)printf("Client (%s) sent: %s\n", rip, buf);
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}
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}
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} while (rval != 0);
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(void)close(fd);
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}
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/*
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* This program shows that the second socket is blocked until we
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* handled socket number one.1
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*/
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int
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main()
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{
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int s1, s2;
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s1 = createSocket();
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s2 = createSocket();
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for (;;) {
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handleSocket(s1);
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handleSocket(s2);
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}
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/* NOTREACHED */
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}
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