TCP server added

computer_networks/lab/lab1/TCP_server.c

@@ -0,0 +1,67 @@
+/**
+ * /mnt/z/my_git/sixth-semester/computer_networks/lab/lab1/TCP_server.c
+ * @author Avinal Kumar
+ * @since January 27, 2021
+ * Roll Number - 185067
+ *
+ * LAB 1 
+*/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <stdlib.h>
+#include <netinet/in.h>
+#include <string.h>
+#define PORT 2047 // Q1: previously 8080
+
+int main(int argc, char const *argv[])
+{
+    int server_fd, new_socket, valread;
+    struct sockaddr_in address;
+    int opt = 1;
+    int addrlen = sizeof(address);
+    char buffer[4096] = {0}; // Q4: changed to 4096
+    char *hello = "TCP Server: Yeah we've got the new message.";
+
+    // Creating socket file descriptor
+    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0)
+    {
+        perror("socket failed");
+        exit(EXIT_FAILURE);
+    }
+
+    // Forcefully attaching socket to the port 8080
+    /*if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) 
+	{ 
+		perror("setsockopt"); 
+		exit(EXIT_FAILURE); 
+	}*/
+    address.sin_family = AF_INET;
+    address.sin_addr.s_addr = inet_addr("127.0.0.1"); // Q4: chenged to localhost
+    address.sin_port = htons(PORT);
+
+    // Forcefully attaching socket to the port 8080
+    if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0)
+    {
+        perror("bind failed");
+        exit(EXIT_FAILURE);
+    }
+    if (listen(server_fd, 7) < 0) // Q2: listen(server_fd, 3)
+    {
+        perror("listen");
+        exit(EXIT_FAILURE);
+    }
+    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t *)&addrlen)) < 0)
+    {
+        perror("accept");
+        exit(EXIT_FAILURE);
+    }
+    valread = read(new_socket, buffer, 4096); // Q4: changed to 4096
+    printf("%s\n", buffer);
+    printf("Processing ...!!!\n");
+    sleep(4);
+    send(new_socket, hello, strlen(hello), 0);
+    printf("New message sent\n");
+    return 0;
+}