server

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

int main() {
  int s, ss, l;
  struct sockaddr_in server, server2, client;   //socketul pentru prima conecxiune, a 2-a si clinet

  s = socket(AF_INET, SOCK_STREAM, 0);
  if (s < 0) {
    printf("Eroare la crearea socketului server\n");
    return 1;
  }

  memset(&server, 0, sizeof(server));
  server.sin_port = htons(1234);
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = INADDR_ANY;

  if (bind(s, (struct sockaddr *) &server, sizeof(server)) < 0) {
    printf("Eroare la bind\n");
    return 1;
  }     //bind pe prima conexiune

  ss = socket(AF_INET, SOCK_STREAM, 0);
  if(ss < 0){
      printf("Eroare la crearea noului socket server\n");
      return 1;
  }

  memset(&server2, 0, sizeof(server2));     //initializare socket server 2
  server2.sin_port = htons(2003);       //cu portul triis
  server2.sin_family = AF_INET;
  server2.sin_addr.s_addr = INADDR_ANY;

  if(bind(ss, (struct sockaddr *) &server2, sizeof(server2)) < 0){
      printf("Eroare la bind 2\n");
      return 1;     //bind pe al 2-lea socket
  }

  listen(s, 5); //listen pe scketul 1
  listen(ss, 5);//listen pe socketul 2


  l = sizeof(client);
memset(&client, 0, sizeof(client));   //curatare client

  while (1) {
    int cc, c;
    c = accept(s, (struct sockaddr *) &client, &l);
    printf("S-a conectat un client.\n");
    // deservirea clientului
    short int port = 2003;
    port = htons(port);
    send(c, &port, sizeof(port), 0);
    short int k=9;
    k=htons(k);
    send(c,&k,sizeof(k),0);

    char a[9]="127.0.0.1";

    for(int i=0;i<9;i++)
        send(c,&a[i],sizeof(a[i]),MSG_WAITALL);


    //trimterea noului port


    memset(&client, 0, sizeof(client));
    l = sizeof(client);
    cc = accept(ss, (struct sockaddr*) &client, &l); //conectarea la clinet prin noul port

    printf("Te-ai conectat din nou :)!\n");
    int num_char;
    recv(cc, &num_char, sizeof(num_char), MSG_WAITALL);
    printf("Numarul de barosi este: %d\n", ntohl(num_char));
    num_char = ntohl(num_char);     //primi numarul de caractere de la client prin portul nou

    char* str = (char*)malloc(num_char*sizeof(char));
    for(int i = 0; i<num_char; i++){
        char a;
        recv(cc, &a, sizeof(a), MSG_WAITALL);   //citim sirul de caractere
        str[i] = a;
    }

    for(int i = 0; i<num_char; i++){
        str[i] = 'B';       //cream un not sir

    int to_send = htonl(num_char);  //trimitem inapoi lungimea
    send(cc, &to_send, sizeof(to_send), 0);
    for(int i = 0; i<num_char; i++){
        send(cc, &str[i], sizeof(str[i]), 0);   //trimitem inapoi sirul
    }
    close(c);
    close(cc);
    // sfarsitul deservirii clientului;
  }
}