UDP client added

computer_networks/lab/lab1/UDPclient.c

@@ -0,0 +1,60 @@
+/**
+ * /mnt/z/my_git/sixth-semester/computer_networks/lab/lab1/UDPclient.c
+ * @author Avinal Kumar
+ * @since January 27, 2021
+ * Roll Number - 185067
+ *
+ * LAB 1
+*/
+
+// Client side implementation of UDP client-server model
+#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 2047	 // Q1: previously 8080
+#define MAXLINE 4096 // Q4: changed to 4096
+
+// Driver code
+int main()
+{
+	int sockfd;
+	char buffer[MAXLINE];
+	char *hello = "UDP Client: Hello this message has been changed. Did you get it?";
+	struct sockaddr_in servaddr;
+
+	// Creating socket file descriptor
+	if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
+	{
+		perror("socket creation failed");
+		exit(EXIT_FAILURE);
+	}
+
+	memset(&servaddr, 0, sizeof(servaddr));
+
+	// Filling server information
+	servaddr.sin_family = AF_INET;
+	servaddr.sin_port = htons(PORT);
+	servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); // Q3: changed to localhost
+
+	int n, len;
+
+	sendto(sockfd, (const char *)hello, strlen(hello),
+		   MSG_CONFIRM, (const struct sockaddr *)&servaddr,
+		   sizeof(servaddr));
+	printf("New message sent.\n");
+
+	n = recvfrom(sockfd, (char *)buffer, MAXLINE,
+				 MSG_WAITALL, (struct sockaddr *)&servaddr,
+				 &len);
+	buffer[n] = '\0';
+	printf("Server : %s\n", buffer);
+
+	close(sockfd);
+	return 0;
+}