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tb-userspace.c
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tb-userspace.c
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#include <stdio.h>
#include <unistd.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <assert.h>
#include <memory.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <pthread.h>
#include <netinet/in.h>
/* compile with
* cc -l pthread -Wall -O2 -s -o tb_userspace tb_userspace.c
*/
struct Threadargs {
int sockv6;
int tun;
int remote_ip;
int tun_mode; /*0 for 6to4, 1 for tunnelbroker, 2 for isatap*/
};
int tun_create(char *dev, int flags)
{
struct ifreq ifr;
int fd, err;
assert(dev != NULL);
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
return fd;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags |= flags;
if (*dev != '\0')
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
if ((err = ioctl(fd, TUNSETIFF, (void *)&ifr)) < 0) {
close(fd);
return err;
}
strcpy(dev, ifr.ifr_name);
return fd;
}
void printip(int ipaddr) {
printf("%d.%d.%d.%d", 0x000000ff&ipaddr, (0x0000ff00&ipaddr)>>8, (0x00ff0000&ipaddr)>>16 ,(0xff000000&ipaddr)>>24);
}//Only for debug
void s2t_thread(void *s2targs) {
int sockv6, tun, ret, res, remote_ip, leniphead, tun_mode;
unsigned char bufsock[4096];
struct tun_pi pi = {0, htons(ETH_P_IPV6)};
/*pi is sth. like link-layer header for device tun and should be set type IPV6*/
sockv6 = (*(struct Threadargs *)s2targs).sockv6;
tun = (*(struct Threadargs *)s2targs).tun;
remote_ip = (*(struct Threadargs *)s2targs).remote_ip;
tun_mode = (*(struct Threadargs *)s2targs).tun_mode;
while (1) {
res = recv(sockv6, bufsock, sizeof(bufsock), 0);
if (res < 0) {
printf("SOCKS ERROR\r\n");
continue;
}
leniphead = 4*(bufsock[0]&0x0f);
if (leniphead>60 || leniphead<20) {
printf("IPv4 header too long\r\n");
continue;
}
if (tun_mode==1) {/*Only accept package with source IPv4 addr the same as tunnel server's*/
if ( *(int *)(&bufsock[12])!=remote_ip ) {
printf("s2t:Drop package from source IPv4 ");
printip(*(int *)(&bufsock[12]));
printf(" not the relay server");
printip(remote_ip);
printf("\r\n");
continue;
}
}
else if (tun_mode==2) {/*In ISATAP mode, we should accept package (IPv6)prefix:0:5efe:xx.xx.xx.xx in (IPv4)xx.xx.xx.xx*/
if ( ( *(int *)(&bufsock[12])!=remote_ip ) && (( *(int *)(&bufsock[(leniphead+16)])!=0xfe5e0000) || ( *(int *)(&bufsock[12])!=*(int *)(&bufsock[leniphead+20])) ) ) {
printf("s2t:Drop package from source IPv4 ");
printip(*(int *)(&bufsock[12]));
printf(" do not corresponds its IPv6 address.\r\n");
continue;
}
}
else if ((tun_mode==0) && ( *(int *)(&bufsock[12])!=remote_ip) ) {/*In 6to4 mode, (IPv6)2002:xxxx:xxxx::/48 in (IPv4)xx.xx.xx.xx should be accepted*/
if ( *(short *)(&bufsock[(leniphead+8)])!=0x0220) {
printf("s2t:Drop package from source IPv4 ");
printip(*(int *)(&bufsock[12]));
printf(" do not corresponds its IPv6 address.\r\n");
continue;
}
else if( (*(int *)(&bufsock[12]))!=(*(int *)(&bufsock[(leniphead+10)]))) {
printf("s2t:Drop package from source IPv4 ");
printip(*(int *)(&bufsock[12]));
printf(" do not corresponds its IPv6 address.\r\n");
continue;
}
}
ret = res - leniphead;
memcpy(&bufsock[leniphead-sizeof(struct tun_pi)], &pi, sizeof(struct tun_pi));
ret = write(tun, &bufsock[leniphead-sizeof(struct tun_pi)], ret + sizeof(struct tun_pi));
// printf("s2t: %d/%d bytes\r\n", res, ret);
}
}
void t2s_thread(void *t2sargs) {
int sockv6, tun, ret, res, remote_ip, tun_mode;
unsigned char buftun[4096];
sockv6 = (*(struct Threadargs *)t2sargs).sockv6;
tun = (*(struct Threadargs *)t2sargs).tun;
remote_ip = (*(struct Threadargs *)t2sargs).remote_ip;
tun_mode = (*(struct Threadargs *)t2sargs).tun_mode;
struct sockaddr_in remoteaddr;
remoteaddr.sin_family = AF_INET;
remoteaddr.sin_port = htons(IPPROTO_IPV6);
bzero(&(remoteaddr.sin_zero), 8);
while (1) {
ret = read(tun, buftun, sizeof(buftun) );
if (ret < 0) {
printf("t2sTUN ERROR\r\n");
continue;
}
remoteaddr.sin_addr.s_addr = remote_ip;
switch (tun_mode) {
case 0:
if (*(short *)(&buftun[(sizeof(struct tun_pi)+24)])==0x0220) {
remoteaddr.sin_addr.s_addr = *(int *)(&buftun[(sizeof(struct tun_pi)+26)]);
}/*send package directly to (IPv4)xx.xx.xx.xx other than default gw 192.88.99.1 when handing (IPv6)2002:xxxx:xxxx::/48 package*/
break;
case 1: break;
case 2:
if ( (*(int *)(&buftun[(sizeof(struct tun_pi)+24)])==*(int *)(&buftun[(sizeof(struct tun_pi)+8)])) && (*(int *)(&buftun[(sizeof(struct tun_pi)+28)])==*(int *)(&buftun[(sizeof(struct tun_pi)+12)])) && (*(int *)(&buftun[(sizeof(struct tun_pi)+32)])==*(int *)(&buftun[(sizeof(struct tun_pi)+16)])) && (*(int *)(&buftun[(sizeof(struct tun_pi)+16)])==0xfe5e0000)) {
remoteaddr.sin_addr.s_addr = *(int *)(&buftun[(sizeof(struct tun_pi)+36)]);
}/*In ISATAP mode, IPv6 packages to /64 neighbours are send directly to their IPv4 address without relay*/
break;
}
res = sendto(sockv6, &buftun[sizeof(struct tun_pi)], ret, 0 ,(struct sockaddr *)&remoteaddr, sizeof(struct sockaddr));
// printf("t2s: %d/%d bytes\r\n", ret ,res);
}
}
int main(int argc, char *argv[])
{
int tun, rets2t, rett2s;
in_addr_t remote_ip;
char tun_name[IFNAMSIZ];
if (argc!=5) {
printf("Usage:%s tun_name remote_ipv4 local_ipv4 mode\r\n",argv[0]);
return 1;
}
strcpy(tun_name, argv[1]);
tun = tun_create(tun_name, IFF_TUN );//| IFF_NO_PI);
if (tun < 0) {
perror("tun_create");
return 1;
}
printf("TUN name is %s\n", tun_name);
int sockv6, if_bind, tun_mode;
sockv6 = socket(AF_INET, SOCK_RAW, IPPROTO_IPV6);
if (sockv6 < 0) {
perror("v4_socket_create");
return 1;
}
printf("IPv4 SOCK_RAW created: %d\r\n", sockv6);
struct sockaddr_in localaddr;
localaddr.sin_family = AF_INET;
localaddr.sin_port = htons(IPPROTO_IPV6);
localaddr.sin_addr.s_addr = inet_addr(argv[3]);
bzero(&(localaddr.sin_zero), 8);
if (localaddr.sin_addr.s_addr != -1) {
if_bind = bind(sockv6, (struct sockaddr *)&localaddr, sizeof(struct sockaddr));
if (if_bind < 0) {
perror("bind local address");
return 1;
}
printf("Bind local IPv4 address ");
printip(localaddr.sin_addr.s_addr);
printf("\r\n");
}/*If local_ipv4(argv[3]) is "any", do not bind local IPv4 address*/
else printf("Do not bind local IPv4 address, using default.\r\n");
pthread_t ids2t, idt2s;
struct Threadargs s2targs, t2sargs;
s2targs.sockv6 = sockv6;
s2targs.tun = tun;
if (!strcmp(argv[4],"sit")) {
if (strcmp(argv[2],"any")) {
remote_ip = inet_addr(argv[2]);
tun_mode = 1;
}
else {
remote_ip = inet_addr("192.88.99.1");
tun_mode = 0;
}
}/*If remote_ipv4(argv[2]) is "any", use 6to4 mode and set default gateway 192.88.99.1*/
else if (!strcmp(argv[4],"isatap")) {
remote_ip = inet_addr(argv[2]);
tun_mode = 2;
}
else {
printf("tunnel mode %s not found.\r\n", argv[4]);
return 1;
}
s2targs.tun_mode = tun_mode;
if (remote_ip == INADDR_NONE) {
printf("Bad remote ipv4 address.\r\n");
return 1;
}
else {
t2sargs.remote_ip = remote_ip;
s2targs.remote_ip = remote_ip;
}
printf("Using remote IPv4 ");
printip(remote_ip);
printf("\r\n");
rets2t = pthread_create(&ids2t, NULL, (void *)s2t_thread, (void *)&s2targs);
t2sargs.sockv6 = sockv6;
t2sargs.tun = tun;
t2sargs.tun_mode = tun_mode;
rett2s = pthread_create(&idt2s, NULL, (void *)t2s_thread, (void *)&t2sargs);
pthread_join(ids2t, NULL);
pthread_join(idt2s, NULL);
return 0;
}