Messo esempio di server elementare.

[gapil.git] / listati / UDP_daytimed.c

diff --git a/listati/UDP_daytimed.c b/listati/UDP_daytimed.c
new file mode 100644 (file)
index 0000000..f43853d
--- /dev/null
+++ b/listati/UDP_daytimed.c
@@ -0,0 +1,47 @@
+int main(int argc, char *argv[])
+{
+    int sock;
+    int i, n, len, verbose=0;
+    struct sockaddr_in addr;
+    char buffer[MAXLINE];
+    time_t timeval;
+    ...
+    /* 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);
+}