server.c

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>

int main(int args, char *argv[]) {

u_int port;
int server;
int client;
int localerror;
struct sockaddr_in myAddr;
struct sockaddr_in cliente_addr;
socklen_t clienteLen;	
int status;

char *cadena;
time_t tiempo = time(0);
struct tm *tlocal = localtime(&tiempo);
char output[128];

    //Validamos los Arguemntos
if(args < 2) {
fprintf(stderr,"Error: Missing Arguments\n");
fprintf(stderr,"\tUSE: %s [PORT]\n",argv[0]);
return 1;
}

port = atoi(argv[1]);
if(port < 1 || port > 65535) {
fprintf(stderr,"Port %i out of range (1-65535)\n",port);
return 1;
}

//Iniciamos la apertura del Socket
server = socket(PF_INET,SOCK_STREAM,0);
if(server == -1) {
localerror = errno;
fprintf(stderr, "Error: %s\n",strerror(localerror));
return 1;
}

//Nos adjudicamos el Puerto.
bzero(&myAddr,sizeof(myAddr));
myAddr.sin_family = AF_INET;
myAddr.sin_addr.s_addr = htonl(INADDR_ANY);
myAddr.sin_port = htons(port);

status = bind(server, (struct sockaddr *)&myAddr, sizeof(myAddr));
if(status != 0) {
localerror = errno;
fprintf(stderr,"Can't Bind Port: %s\n",strerror(localerror));
close(server);
return 1;
}

//Nos ponemos el modo de Escucha
status = listen(server,5);
if(status == -1) {
localerror = errno;
fprintf(stderr,"Can't listen on socket(%s)\n",strerror(localerror));
close(server);
return 1;
}	

//Esperamos una Conexión
while(1) {
bzero(&cliente_addr,sizeof(cliente_addr));
client = accept(server,(struct sockaddr *)&cliente_addr,&clienteLen);
if(client == -1) {
localerror = errno;
fprintf(stderr,"Error acepting conection %s\n",strerror(localerror));
close(server);
return 1;
}

//Inicia el protocolo...
cadena = (char *) calloc(1,20);
while(strcmp(cadena,"Adios\r\n")!=0) {
bzero(cadena,20);
status=read(client,cadena,20);
printf("Nos envio %s\n\n",cadena);
strftime(output,128,"%d/%m/%y %H:%M:%S",tlocal);

status=write(client,output,strlen(output));
if(status != strlen(output)) {
fprintf(stderr,"Se enviaron solo %i de %lu bytes\n",status,strlen(output));
return 1;
}
}

free(cadena);
close(client);
}

//close(server);

return 0;
}