#include<stdio.h>
#include<string.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<netdb.h>

#define MSIZE 255       //lungimea maxima a mesajului
#define PORT 12345      //portul la care asculta

main()
{
 int socketd,i,len_addr,sd;
 char msg[MSIZE],reply[MSIZE],s[MSIZE];
 struct sockaddr_in sock,sock_client;
 struct hostent *hent;

 //construim un socket stream (orientat conexiune; TCP) pentru domeniul IPv4
 //Internet Protocol (AF_INET)
 socketd=socket(AF_INET,SOCK_STREAM,0);
 printf("Creare socket socketd=%d\n",socketd);
 //curat continutul lui sock (scriu 0)
 memset((char *)&sock,0,sizeof(sock));
 sock.sin_family=AF_INET;                         //domeniul Internet  
 sock.sin_addr.s_addr=htonl(INADDR_ANY);          //adresa IP la care asculta serverul (INADDR_ANY=oricare)
 sock.sin_port=htons(12345);                      //portul server
 
 //legam socketul de structura sock (rezervam portul in kernel) 
 if( bind(socketd,(struct sockaddr *) &sock,sizeof(sock)) <0)
           { perror("Eroare la bind.\n");
             exit(1);
           }
 
 //punem serverul in starea de asteptare de conexiuni
 listen(socketd,2);
 printf("Serverul asteapta conexiuni..\n");
 while(1) {
       len_addr=sizeof(struct sockaddr);
       //am o conexiune ==> sd este descriptorul de socket pt conexiunea cu clientul sock_client
       sd=accept(socketd,(struct sockaddr *) & sock_client,&len_addr);
       printf("Am client.\n");
       
       //pentru fiecare client cream un proces fiu care se va ocupa de el       
       if(fork()==0) {
          i=recv(sd, msg, MSIZE,0);
          if(i>255 || i<=0) {close(sd); exit(1);}
          msg[i]='\0';
          printf("Am primit de la client: %s\n",msg);
          
          //verificam daca mesajul de la client incepe cu "HELLO;"
          if (strstr(msg,"HELLO;")==msg) {
               strcpy(s,(char *) (msg+6));
               strcpy(reply,"HELLO ");
               strcat(reply,s);
               strcat(reply,"! ");
               if (!(hent = gethostbyname ("127.0.0.1")))
                     {perror("Eroare la gethostbyname.\n"); exit(1);}
               strcat(reply,(char *)(char *)hent->h_name);
               strcat(reply," is pleased to meet you.");
               printf("Trimit la client: %s\n",reply);
               send(sd,reply,strlen(reply),0);                               
               } 
           else {
               strcpy(reply,"200 Message not understood!");
               send(sd,reply,strlen(reply),0);
               }
           close(sd);        
          }            
     }
}