121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/* Byte Stream Connection Server Example
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Copyright (C) 1991-2022 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <stdlib.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 <netdb.h>
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#define PORT 5555
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#define MAXMSG 512
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int
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read_from_client (int filedes)
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{
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char buffer[MAXMSG];
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int nbytes;
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nbytes = read (filedes, buffer, MAXMSG);
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if (nbytes < 0)
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{
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/* Read error. */
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perror ("read");
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exit (EXIT_FAILURE);
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}
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else if (nbytes == 0)
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/* End-of-file. */
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return -1;
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else
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{
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/* Data read. */
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fprintf (stderr, "Server: got message: `%s'\n", buffer);
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return 0;
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}
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}
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int
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main (void)
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{
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extern int make_socket (uint16_t port);
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int sock;
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fd_set active_fd_set, read_fd_set;
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int i;
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struct sockaddr_in clientname;
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size_t size;
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/* Create the socket and set it up to accept connections. */
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sock = make_socket (PORT);
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if (listen (sock, 1) < 0)
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{
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perror ("listen");
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exit (EXIT_FAILURE);
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}
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/* Initialize the set of active sockets. */
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FD_ZERO (&active_fd_set);
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FD_SET (sock, &active_fd_set);
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while (1)
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{
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/* Block until input arrives on one or more active sockets. */
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read_fd_set = active_fd_set;
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if (select (FD_SETSIZE, &read_fd_set, NULL, NULL, NULL) < 0)
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{
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perror ("select");
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exit (EXIT_FAILURE);
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}
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/* Service all the sockets with input pending. */
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for (i = 0; i < FD_SETSIZE; ++i)
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if (FD_ISSET (i, &read_fd_set))
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{
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if (i == sock)
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{
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/* Connection request on original socket. */
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int new;
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size = sizeof (clientname);
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new = accept (sock,
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(struct sockaddr *) &clientname,
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&size);
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if (new < 0)
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{
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perror ("accept");
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exit (EXIT_FAILURE);
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}
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fprintf (stderr,
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"Server: connect from host %s, port %hd.\n",
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inet_ntoa (clientname.sin_addr),
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ntohs (clientname.sin_port));
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FD_SET (new, &active_fd_set);
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}
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else
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{
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/* Data arriving on an already-connected socket. */
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if (read_from_client (i) < 0)
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{
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close (i);
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FD_CLR (i, &active_fd_set);
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}
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}
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}
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}
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}
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