C socket demo

I. Server-server. c

# Include <stdio. h> # include <sys/socket. h> # include <ARPA/inet. h> # include <stdlib. h> # include <string. h> # include <unistd. h> # include <netinet/in. h> # define maxpending 5 # define buffsize 32 void die (char * mess) {perror (MESS); exit (1);} void handleclient (INT sock) {char buffer [buffsize]; int writable ED =-1; if (cached ED = Recv (sock, buffer, buffsize, 0) <0) {die ("failed to recevie in1_bytes from client ");} While (bounded ed> 0) {If (send (sock, buffer, cached ed, 0 )! = Committed ed) {die ("failed to send bytes to client");} If (cached ED = Recv (sock, buffer, buffsize, 0) <0) {die ("failed to receive additional bytes from client") ;}} close (sock) ;}int main (INT argc, char * argv []) {int serversock, clientsock; struct sockaddr_in echoserver, echoclient; If (argc! = 2) {fprintf (stderr, "Usage: echoserver <port>/N"); exit (1) ;}if (serversock = socket (pf_inet, sock_stream, ipproto_tcp )) <0) {die ("failed to create socket");} memset (& echoserver, 0, sizeof (echoserver); echoserver. sin_family = af_inet; echoserver. sin_addr.s_addr = htonl (inaddr_any); echoserver. sin_port = htons (atoi (argv [1]); If (BIND (serversock, (struct sockaddr *) & echoserver, sizeof (echoserver) <0) {die ("failed to bind the server socket");} If (Listen (serversock, maxpending) <0) {die ("failed to listen on server socket ");} while (1) {unsigned int clientlen = sizeof (echoclient); If (clientsock = accept (serversock, (struct sockaddr *) & echoclient, & clientlen) <0) {die ("failed to accept client connection");} fprintf (stdout, "Client Connected: % s/n", inet_ntoa (echoclient. sin_addr); handleclient (clientsock );}} 

 

Ii. Client-client. c

# Include <stdio. h> # include <sys/socket. h> # include <ARPA/inet. h> # include <stdlib. h> # include <string. h> # include <unistd. h> # include <netinet/in. h> # define buffsize 32 # define FP fprintfvoid die (char * mess) {perror (MESS); exit (1);} int main (INT argc, char * argv []) {int sock; struct sockaddr_in echoserver; char buffer [buffsize]; unsigned int echolen; int received = 0; If (argc! = 4) {FP (stderr, "Usage: TCP echo <server_ip> <word> <port>/N"); exit (1 );} if (sock = socket (pf_inet, sock_stream, ipproto_tcp) <0) {die ("failed to create socket");} memset (& echoserver, 0, sizeof (echoserver); echoserver. sin_family = af_inet; echoserver. sin_addr.s_addr = inet_addr (argv [1]); echoserver. sin_port = htons (atoi (argv [3]); If (connect (sock, (struct sockaddr *) & echoserver, sizeof (Echoserver) <0) {die ("failed to connect with server");} echolen = strlen (argv [2]); If (send (sock, argv [2], echolen, 0 )! = Echolen) {die ("mismatch in number of sent bytes");} FP (stdout, "Received:"); While (received <echolen) {int bytes = 0; if (Bytes = Recv (sock, buffer, BUFFSIZE-1, 0) <1) {die ("failed to receive bytes from server");} received + = bytes; buffer [bytes] = '/0'; FP (stdout, buffer);} FP (stdout, "/N"); close (sock); exit (0 );}