Messo esempio di server elementare.

[gapil.git] / sources / UDP_daytimed.c

diff --git a/sources/UDP_daytimed.c b/sources/UDP_daytimed.c
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+/* UDP_daytimed.c
+ * 
+ * Copyright (C) 2004 Simone Piccardi
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/****************************************************************
+ *
+ * Program daytimed: 
+ * Elementary TCP server for daytime service (port 13)
+ *
+ * Author: Simone Piccardi
+ * Mar. 2004
+ *
+ * Usage: daytimed -h give all info
+ *
+ * $Id: UDP_daytimed.c,v 1.1 2004/03/21 18:30:35 piccardi Exp $
+ *
+ ****************************************************************/
+/* 
+ * Include needed headers
+ */
+#include <sys/types.h>   /* predefined types */
+#include <unistd.h>      /* include unix standard library */
+#include <arpa/inet.h>   /* IP addresses conversion utiliites */
+#include <sys/socket.h>  /* socket library */
+#include <stdio.h>      /* include standard I/O library */
+#include <time.h>
+
+#define MAXLINE 80
+/* Program begin */
+void usage(void);
+int main(int argc, char *argv[])
+{
+/* 
+ * Variables definition  
+ */
+    int sock;
+    int i, n, len, verbose=0;
+    struct sockaddr_in addr;
+    char buffer[MAXLINE];
+    time_t timeval;
+    /*
+     * Input section: decode parameters passed in the calling 
+     * Use getopt function
+     */
+    opterr = 0;         /* don't want writing to stderr */
+    while ( (i = getopt(argc, argv, "hv")) != -1) {
+       switch (i) {
+       /* 
+        * Handling options 
+        */ 
+       case 'h':  
+           printf("Wrong -h option use\n");
+           usage();
+           return(0);
+           break;
+       case 'v':
+           verbose = 1;
+           break;
+       case '?':   /* unrecognized options */
+           printf("Unrecognized options -%c\n",optopt);
+           usage();
+       default:    /* should not reached */
+           usage();
+       }
+    }
+    /* ***********************************************************
+     * 
+     *          Options processing completed
+     *
+     *               Main code beginning
+     * 
+     * ***********************************************************/
+    /* create socket */
+    if ( (sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+       perror("Socket creation error");
+       exit(-1);
+    }
+    /* initialize address */
+    memset((void *)&addr, 0, sizeof(addr));     /* clear server address */
+    addr.sin_family = AF_INET;                  /* address type is INET */
+    addr.sin_port = htons(13);                  /* daytime port is 13 */
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);   /* connect from anywhere */
+    /* bind socket */
+    if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+       perror("bind error");
+       exit(-1);
+    }
+    /* write daytime to client */
+    while (1) {
+       timeval = time(NULL);
+       n = recvfrom(sock, buffer, MAXLINE, 0, (struct sockaddr *)&addr, &len);
+       if (n < 0) {
+           perror("recvfrom error");
+           exit(-1);
+       }
+       if (verbose) {
+           inet_ntop(AF_INET, &addr.sin_addr, buffer, sizeof(buffer));
+           printf("Request from host %s, port %d\n", buffer,
+                  ntohs(addr.sin_port));
+       }
+       snprintf(buffer, sizeof(buffer), "%.24s\r\n", ctime(&timeval));
+       n = sendto(sock, buffer, strlen(buffer), 0, 
+                  (struct sockaddr *)&addr, sizeof(addr));
+       if (n < 0) {
+           perror("sendto error");
+           exit(-1);
+       }
+    }
+    /* normal exit */
+    exit(0);
+}
+/*
+ * routine to print usage info and exit
+ */
+void usage(void) {
+    printf("Simple daytime server\n");
+    printf("Usage:\n");
+    printf("  daytimed [-hv] \n");
+    printf("  -h          print this help\n");
+    printf("  -v          print request source on stdout\n");
+    exit(1);
+}