/************************************************************************** * simpletun.c * * * * A simplistic, simple-minded, naive tunnelling program using tun/tap * * interfaces and TCP. DO NOT USE THIS PROGRAM FOR SERIOUS PURPOSES. * * * * You have been warned. * * * * (C) 2010 Davide Brini. * * * * DISCLAIMER AND WARNING: this is all work in progress. The code is * * ugly, the algorithms are naive, error checking and input validation * * are very basic, and of course there can be bugs. If that's not enough, * * the program has not been thoroughly tested, so it might even fail at * * the few simple things it should be supposed to do right. * * Needless to say, I take no responsibility whatsoever for what the * * program might do. The program has been written mostly for learning * * purposes, and can be used in the hope that is useful, but everything * * is to be taken "as is" and without any kind of warranty, implicit or * * explicit. See the file LICENSE for further details. * *************************************************************************/ #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 <pthread.h> /* buffer for reading from tun/tap interface, must be >= 1500 */ #define BUFSIZE 200000 #define CLIENT 0 #define SERVER 1 #define PORT 55555 #define FILEOUT 1 int debug; char *progname; int recv_control_flag, type, value, tap2netInterval = 50; int net_fd; struct sockaddr_in dst_addr; /************************************************************************** * tun_alloc: allocates or reconnects to a tun/tap device. The caller * * must reserve enough space in *dev. * **************************************************************************/ int tun_alloc(char *dev, int flags) { struct ifreq ifr; int fd, err; char *clonedev = "/dev/net/tun"; if( (fd = open(clonedev , O_RDWR)) < 0 ) { perror("Opening /dev/net/tun"); return fd; } memset(&ifr, 0, sizeof(ifr)); ifr.ifr_flags = flags; if (*dev) { strncpy(ifr.ifr_name, dev, IFNAMSIZ); } if( (err = ioctl(fd, TUNSETIFF, (void *)&ifr)) < 0 ) { perror("ioctl(TUNSETIFF)"); close(fd); return err; } strcpy(dev, ifr.ifr_name); return fd; } /************************************************************************** * cread: read routine that checks for errors and exits if an error is * * returned. * **************************************************************************/ int cread(int fd, char *buf, int n){ int nread; if((nread=read(fd, buf, n)) < 0){ perror("Reading data"); exit(1); } return nread; } /************************************************************************** * cwrite: write routine that checks for errors and exits if an error is * * returned. * **************************************************************************/ int cwrite(int fd, char *buf, int n){ int nwrite; if((nwrite=write(fd, buf, n)) < 0){ perror("Writing data"); exit(1); } return nwrite; } /************************************************************************** * read_n: ensures we read exactly n bytes, and puts them into "buf". * * (unless EOF, of course) * **************************************************************************/ int read_n(int fd, char *buf, int n) { int nread, left = n; while(left > 0) { if ((nread = cread(fd, buf, left)) == 0){ return 0 ; }else { left -= nread; buf += nread; } } return n; } /************************************************************************** * do_debug: prints debugging stuff (doh!) * **************************************************************************/ void do_debug(char *msg, ...){ va_list argp; if(debug) { va_start(argp, msg); vfprintf(stderr, msg, argp); va_end(argp); } } /************************************************************************** * my_err: prints custom error messages on stderr. * **************************************************************************/ void my_err(char *msg, ...) { va_list argp; va_start(argp, msg); vfprintf(stderr, msg, argp); va_end(argp); } /************************************************************************** * usage: prints usage and exits. * **************************************************************************/ void usage(void) { fprintf(stderr, "Usage:\n"); fprintf(stderr, "%s -i <ifacename> [-s|-c <serverIP>] [-p <port>] [-u|-a] [-d]\n", progname); fprintf(stderr, "%s -h\n", progname); fprintf(stderr, "\n"); fprintf(stderr, "-i <ifacename>: Name of interface to use (mandatory)\n"); fprintf(stderr, "-s|-c <serverIP>: run in server mode (-s), or specify server address (-c <serverIP>) (mandatory)\n"); fprintf(stderr, "-p <port>: port to listen on (if run in server mode) or to connect to (in client mode), default 55555\n"); fprintf(stderr, "-u|-a: use TUN (-u, default) or TAP (-a)\n"); fprintf(stderr, "-d: outputs debug information while running\n"); fprintf(stderr, "-m: tun or tap ip address\n"); fprintf(stderr, "-h: prints this help text\n"); exit(1); } void *recv_control(void *para) { int cfd = socket(AF_INET, SOCK_DGRAM, 0); if (cfd < 0) { perror("socket error"); exit(1); } struct sockaddr_in serv; struct sockaddr_in clientsock; bzero(&serv, sizeof(serv)); serv.sin_family = AF_INET; serv.sin_port = htons(12366); serv.sin_addr.s_addr = htonl(INADDR_ANY); bind(cfd, (struct sockaddr *)&serv, sizeof(serv)); int i; int n; socklen_t len; uint32_t buf[100]; while (1) { memset(buf, 0x00, sizeof(buf)); len = sizeof(clientsock); n = recvfrom(cfd, buf, sizeof(buf), 0, (struct sockaddr *)&clientsock, &len); for (int i = 0; i < n; i++) { do_debug("%d ", buf[i]); } do_debug("\n"); if ((buf[0] == 0xffffffff) && (buf[1] == 1 || buf[1] == 2) && (buf[2] >= 1 && buf[2] <= 3)) { recv_control_flag = 1; type = buf[1]; value = buf[2]; int32_t control_message[3]; if (type == 2) { control_message[0] = 0xAAAAAAAA; if (value == 1) { tap2netInterval = 50; } else if (value == 2) { tap2netInterval = 250; } int len = sendto(net_fd, control_message, 4, 0, (struct sockaddr *)&dst_addr, sizeof(dst_addr)); do_debug("send reset message len : %d\n", len); sleep(7); } control_message[0] = 0xFFFFFFFF; control_message[1] = type; control_message[2] = value; int len = sendto(net_fd, control_message, 12, 0, (struct sockaddr *)&dst_addr, sizeof(dst_addr)); do_debug("send handout message len : %d\n", len); } else { printf("receive syntax error\n"); } sleep(1); } close(cfd); } int main(int argc, char *argv[]) { int tap_fd, option; int flags = IFF_TUN; char if_name[IFNAMSIZ] = ""; int maxfd; uint32_t nread, nwrite, plength; char buffer[BUFSIZE]; struct sockaddr_in local, remote; char remote_ip[16] = ""; /* dotted quad IP string */ char local_ip[16] = ""; char if_ipaddress[20] =""; unsigned short int port = PORT; unsigned short int rm_port = PORT; int sock_fd, optval = 1; socklen_t remotelen; int cliserv = -1; /* must be specified on cmd line */ unsigned long int tap2net = 0, net2tap = 0; char *Mode[2] = {"tun", "tap"}; int mode = 0; int connected_flag = 0; recv_control_flag = 0; progname = argv[0]; /* Check command line options */ while((option = getopt(argc, argv, "i:s:c:p:r:uahdm:")) > 0) { switch(option) { case 'd': debug = 1; break; case 'h': usage(); break; case 'i': strncpy(if_name,optarg, IFNAMSIZ-1); break; case 's': cliserv = SERVER; strncpy(remote_ip,optarg,15); break; case 'c': cliserv = CLIENT; strncpy(local_ip,optarg,15); break; case 'p': port = atoi(optarg); break; case 'r': rm_port = atoi(optarg); break; case 'u': flags = IFF_TUN; break; case 'a': flags = IFF_TAP; mode = 1; break; case 'm': strncpy(if_ipaddress,optarg,20); break; default: my_err("Unknown option %c\n", option); usage(); } } argv += optind; argc -= optind; if(argc > 0) { my_err("Too many options!\n"); usage(); } if(*if_name == '\0') { my_err("Must specify interface name!\n"); usage(); } else if(cliserv < 0) { my_err("Must specify client or server mode!\n"); usage(); } else if((cliserv == CLIENT)&&(*remote_ip == '\0')) { my_err("Must specify server address!\n"); usage(); } #if 0 char *gnb = "gnb.txt"; char *ue = "ue.txt"; FILE *gnb_fd, *ue_fd; gnb_fd = fopen(gnb, "w"); ue_fd = fopen(ue, "w"); if (gnb_fd == NULL || ue_fd == NULL) { fprintf(stderr, "can't open file\n"); return 1; } #endif char cmd[256]; snprintf(cmd, sizeof(cmd), "sudo ip tuntap del %s mode tap",if_name); system(cmd); snprintf(cmd, sizeof(cmd), "sudo ip tuntap del %s mode tun",if_name); system(cmd); if(*if_ipaddress != '\0'){ // char *if_ipaddress = "6.6.6.1/24"; snprintf(cmd, sizeof(cmd), "sudo ip tuntap add %s mode %s",if_name, Mode[mode]); system(cmd); snprintf(cmd, sizeof(cmd), "sudo ip addr add %s dev %s", if_ipaddress,if_name); system(cmd); snprintf(cmd, sizeof(cmd), "sudo ip link set dev %s up", if_name); system(cmd); char *remote_tun = (char *)malloc(sizeof(if_ipaddress)); memcpy(remote_tun, if_ipaddress, sizeof(if_ipaddress)); char *lastDot = strrchr(remote_tun, '.'); // int lastOctet = atoi(lastDot + 1); sprintf(lastDot + 1, "0/24"); do_debug("remote_tun ip: %s\n", remote_tun); snprintf(cmd, sizeof(cmd), "sudo ip route add %s dev %s", remote_tun, if_name); system(cmd); } // printf("pass\n"); /* initialize tun/tap interface */ if ( (tap_fd = tun_alloc(if_name, flags | IFF_NO_PI)) < 0 ) { my_err("Error connecting to tun/tap interface %s!\n", if_name); exit(1); } do_debug("Successfully connected to interface %s ip address %s\n", if_name, if_ipaddress); /*while(1){ nread = cread(tap_fd, buffer, BUFSIZE); tap2net++; do_debug("TAP2NET %lu: Read %d bytes from the tap interface\n", tap2net, nread); }*/ pthread_t pthread_recv = 0; int recv_flag = pthread_create(&pthread_recv, NULL, &recv_control, NULL); if (recv_flag != 0) { printf("create control_input failed\n"); } if ( (sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { perror("socket()"); exit(1); } // 第二步：绑定地址(IP + Port) struct sockaddr_in myaddr; myaddr.sin_family = AF_INET; myaddr.sin_addr.s_addr = inet_addr(local_ip); myaddr.sin_port = htons(port); if(bind(sock_fd, (struct sockaddr*)&myaddr, sizeof(myaddr)) == -1) { perror("bind"); return 1; } // 第三步：收发数据 // 发送数�? // 指定接收方地址 dst_addr.sin_family = AF_INET; dst_addr.sin_addr.s_addr = inet_addr(remote_ip);//命令行输入接收方IP dst_addr.sin_port = htons(rm_port);//命令行输入端口号 net_fd = sock_fd; /* use select() to handle two descriptors at once */ maxfd = (tap_fd > net_fd)?tap_fd:net_fd; socklen_t len = sizeof(struct sockaddr_in); struct sockaddr_in serveraddr; while(1) { int ret; fd_set rd_set; FD_ZERO(&rd_set); FD_SET(tap_fd, &rd_set); FD_SET(net_fd, &rd_set); ret = select(maxfd + 1, &rd_set, NULL, NULL, NULL); if (ret < 0 && errno == EINTR){ continue; } if (ret < 0) { perror("select()"); exit(1); } if(FD_ISSET(tap_fd, &rd_set)) { /* data from tun/tap: just read it and write it to the network */ usleep(tap2netInterval); nread = cread(tap_fd, buffer, BUFSIZE); if ((buffer[0]&0xf0)>>4 == 6) continue; tap2net++; do_debug("TAP2NET %lu: Read %d bytes from the tap interface\n", tap2net, nread); /* write length + packet */ //plength = htons(nread); //nwrite = cwrite(net_fd, (char *)&plength, sizeof(plength)); //nwrite = cwrite(net_fd, buffer, nread); sendto(net_fd, buffer, nread, 0, (struct sockaddr *)&dst_addr, sizeof(dst_addr)); do_debug("TAP2NET %lu: Written %d bytes to the network\n", tap2net, nread); #if 1 do_debug("TAP2NET %lu: ", tap2net); for (int i = 0; i < nread; i++){ // if (buffer[i] != 0) // fprintf(gnb_fd, "%02hhx ", buffer[i]); do_debug("%02hhx ", buffer[i]); } //fprintf(gnb_fd, "\n"); do_debug("\n"); #endif } if(FD_ISSET(net_fd, &rd_set)) { /* data from the network: read it, and write it to the tun/tap interface. * We need to read the length first, and then the packet */ /* Read length */ //nread = read_n(net_fd, (char *)&plength, sizeof(plength)); // nread = read_n(net_fd, buffer, BUFSIZE);//ntohs(plength)); remotelen = sizeof(dst_addr); nread = recvfrom(net_fd, buffer, BUFSIZE, 0, (struct sockaddr *)&dst_addr, &remotelen); do_debug("recv:%d\n", nread); if(nread == 0) { /* ctrl-c at the other end */ break; } for (int i = 0; i < nread; i++){ do_debug("%02hhx ", buffer[i]); } do_debug("\n"); net2tap++; // if (nread > 200) printf("recv:%d\n", nread); /* read packet */ // nread = read_n(net_fd, buffer, ntohs(plength)); // do_debug("NET2TAP %lu: Read %d bytes from the network\n", net2tap, nread); /* now buffer[] contains a full packet or frame, write it into the tun/tap interface */ nwrite = write(tap_fd, buffer, nread); do_debug("NET2TAP %lu: Written %d bytes to the tap interface\n", net2tap, nwrite); if (connected_flag == 0) { my_err("baseband successful\n"); connected_flag = 1; } #if 0 do_debug("NET2TAP %lu: ", net2tap); for (int i = 0; i < nwrite; i++){ if (buffer[i] != 0) fprintf(ue_fd, "%02hhx ", buffer[i]); do_debug("%02hhx ", buffer[i]); } fprintf(ue_fd, "\n"); do_debug("\n"); #endif } } return(0); }