tun.h

#ifndef TUN_H_
#define TUN_H_

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <linux/if_tun.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <arpa/inet.h> 
#include <sys/select.h>
#include <sys/time.h>
#include <errno.h>
#include <stdarg.h>
#include <assert.h>
#include <unordered_map>

using namespace std;

/* buffer for reading from tun/tap interface, must be >= 1500 */
//#define PKT_SIZE 2000   
#define PORT_ETH 55554
#define PORT_ATH 55555


class Tun {
 public:
  enum IOType {
    kTun=1,
    kWspace, 
    kCellular, 
    kControl,
  };

  Tun(): tun_type_(IFF_TUN), port_eth_(PORT_ETH) {
    bzero(if_name_, sizeof(if_name_));
    bzero(controller_ip_eth_, sizeof(controller_ip_eth_));
  }

  ~Tun() {
    close(tun_fd_);
    close(sock_fd_eth_);
  }
  
  void InitSock();
  int AllocTun(char *dev, int flags);
  int CreateSock();
  void BindSocket(int fd, sockaddr_in *addr);
  void CreateAddr(const char *ip, int port, sockaddr_in *addr);
  uint16_t Read(const IOType &type, char *buf, uint16_t len);
  uint16_t Write(const IOType &type, char *buf, uint16_t len, sockaddr_in *server_addr_eth);
  bool IsValidClient(int client_id);

// Data members:
  int tun_fd_;
  int tun_type_;        // TUN or TAP
  char if_name_[IFNAMSIZ];

  unordered_map<int, char [16]> bs_ip_tbl_; // <bs_id, bs_ip_eth_>.
  unordered_map<int, char [16]> client_ip_tbl_; // <client_id, client_ip_eth_>.

  uint16_t port_eth_;
  int sock_fd_eth_;

  char controller_ip_eth_[16];
  struct sockaddr_in controller_addr_eth_;
};

int cread(int fd, char *buf, int n);
int cwrite(int fd, char *buf, int n);
int read_n(int fd, char *buf, int n);

#endif