posix-server.c

/* SPDX-License-Identifier: BSD-3-Clause */
/*
 * Authors: Costin Lupu <costin.lupu@cs.pub.ro>
 *
 * Copyright (c) 2020, University Politehnica of Bucharest. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define PORT      5000
#define MAXLINE   1024


int main(int argc, char **argv)
{
    int sockfd;
    char buffer[MAXLINE];
    char *ack = "ACK";
    struct sockaddr_in servaddr, cliaddr;
    int rc;
    int len, n;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        fprintf(stderr, "error socket() sockfd=%d\n", sockfd);
        rc = -1;
        goto out;
    }

    memset(&servaddr, 0, sizeof(servaddr));
    memset(&cliaddr, 0, sizeof(cliaddr));

    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    rc = bind(sockfd, (const struct sockaddr *) &servaddr, sizeof(servaddr));
    if (rc < 0) {
        fprintf(stderr, "bind failed");
        goto out;
    }

    while (1) {
        len = sizeof(cliaddr);
        n = recvfrom(sockfd, (char*) buffer, MAXLINE,
                MSG_WAITALL, (struct sockaddr*) &cliaddr, &len);
        if (n < 0) {
            fprintf(stderr, "error recvfrom() n=%d\n", n);
            rc = -1;
            goto out;
        }
        buffer[n] = '\0';

        printf("Client : %s\n", buffer);
        n = sendto(sockfd, (const char*) ack, strlen(ack), MSG_CONFIRM,
                (const struct sockaddr*) &cliaddr, len);
        if (n < 0) {
            fprintf(stderr, "error sendto() n=%d\n", n);
            rc = -1;
            goto out;
        }
        printf("ack sent.\n");
    }

out:
    return rc;
}