examples: Example showing client-server communication using tcp sockets

Example used send and recv apis to transfer messages.

Signed-off-by: Rajalaxmi Angadi <[email protected]>

Author: rajalaxmia

examples/Makefile

@@ -5,7 +5,7 @@ CFLAGS		= -g -O0 $(INCLUDES) $(LIBS)
 LDFLAGS		= -lfabric
 EXEC_PREFIX	= fi_example_
 
-PROGRAMS = rdm msg rdm_tagged rdm_rma
+PROGRAMS = rdm msg rdm_tagged rdm_rma tcp_socket
 
 EXECUTABLES = $(addprefix $(EXEC_PREFIX), $(PROGRAMS))
 

examples/README.md

@@ -78,3 +78,17 @@ FI_PROVIDER=<prov> ./fi_example_rdm_rma
 ```bash
 FI_PROVIDER=<prov> ./fi_example_rdm_rma <server_addr>
 ```
+
+### fi_example_tcp_socket (tcp_socket.c)
+
+This example uses tcp sockets with a simple server and client to showcase send and receive messages.
+
+#### Server
+```bash
+./fi_example_tcp_socket -s <server_addr>
+```
+
+#### Client
+```bash
+./fi_example_tcp_socket -s <server_addr> -c
+```

examples/tcp_socket.c

@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <getopt.h>
+#include <stdbool.h>
+
+#define PORT 43192
+
+char *serv_addr = NULL;
+bool client_flag = 0;
+
+int main(int argc, char *argv[])
+{
+	int socket_desc, client_sock, client_size, op;
+	struct sockaddr_in server_addr, client_addr;
+	char server_message[256];
+	char client_message[256] = "Hello, server! I am the client you've been waiting for!";
+
+	while ((op = getopt(argc, argv, "hs:c")) != -1) {
+		switch (op) {
+		case 's':
+			serv_addr = optarg;
+			break;
+		case 'c':
+			client_flag = 1;
+			break;
+		default:
+		case '?':
+		case 'h':
+			printf(argv[0], "A simple tcp client-server example.\n");
+			printf("-s <server's ip address>\n");
+			printf("-c  => indicating this is client\n");
+			return 0;
+		}
+	}
+
+	if (!serv_addr) {
+		printf("Need a server address\n");
+		return -1;
+	}
+
+	// Clean buffers:
+	memset(server_message, '\0', sizeof(server_message));
+
+	// Create socket:
+	socket_desc = socket(AF_INET, SOCK_STREAM, 0);
+
+	if (socket_desc < 0) {
+		printf("Error while creating socket\n");
+		return -1;
+	}
+	printf("Socket created successfully\n");
+
+	// Set port and IP:
+	server_addr.sin_family = AF_INET;
+	server_addr.sin_port = htons(PORT);
+	server_addr.sin_addr.s_addr = inet_addr(serv_addr);
+	if (!client_flag) {
+		// Bind to the set port and IP:
+		if (bind(socket_desc, (struct sockaddr*)&server_addr,
+			 sizeof(server_addr)) < 0) {
+			printf("Couldn't bind to the port\n");
+			return -1;
+		}
+		printf("Binding complete\n");
+
+		// Listen for clients:
+		if (listen(socket_desc, 1) < 0) {
+			printf("Error while listening\n");
+			return -1;
+		}
+		printf("Listening for incoming connections...\n");
+
+		// Accept an incoming connection:
+		client_size = sizeof(client_addr);
+		client_sock = accept(socket_desc,
+				     (struct sockaddr*)&client_addr,
+				     &client_size);
+
+		if (client_sock < 0) {
+			printf("Can't accept\n");
+			return -1;
+		}
+		printf("Client connected at IP: %s and port: %i\n",
+			inet_ntoa(client_addr.sin_addr),
+			ntohs(client_addr.sin_port));
+
+		// Receive client's message:
+		if (recv(client_sock, client_message,
+			 sizeof(client_message), 0) < 0) {
+			printf("Couldn't receive\n");
+			return -1;
+		}
+		printf("Msg from client: %s\n", client_message);
+
+		// Respond to client:
+		strcpy(server_message, "Hello! This is the server.");
+
+		if (send(client_sock, server_message,
+			 strlen(server_message), 0) < 0) {
+			printf("Can't send\n");
+			return -1;
+		}
+	}
+
+	if (client_flag) {
+		// Send connection request to server:
+		if (connect(socket_desc, (struct sockaddr*)&server_addr,
+			    sizeof(server_addr)) < 0) {
+			printf("Unable to connect\n");
+			return -1;
+		}
+		printf("Connected with server successfully\n");
+
+		// Send the message to server:
+		if (send(socket_desc, client_message,
+			 strlen(client_message), 0) < 0) {
+			printf("Unable to send message\n");
+			return -1;
+		}
+
+		// Receive the server's response:
+		if (recv(socket_desc, server_message,
+			 sizeof(server_message), 0) < 0) {
+			printf("Error while receiving server's msg\n");
+			return -1;
+		}
+		printf("Server's response: %s\n",server_message);
+	}
+
+	close(client_sock);
+
+	close(socket_desc);
+
+	return 0;
+}