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/* fatvpn client by eeeee
* Public Domain */
#include "config.h"
#include "common.h"
#include <netdb.h>
#define LOGFILE "/tmp/fatvpn.log"
#define TIMEOUT_P 10 /* ping timeout in seconds */
int main(int argc, char *argv[]){
u8 *pkt;
s32 tmp, res, tap, fdmax, skt;
u32 lptime;
struct sockaddr_storage srv, sender;
struct addrinfo *srvi;
struct timespec t;
struct timeval slp;
struct termios attr;
struct ifreq ifr;
fd_set rset;
/* arguments */
if (argc != 4){
fprintf(stderr, "Using:\n\t"
"%s <tap name> <address> <port>\n\n"
"Example:\n\t"
"%s fvpn0 169.254.123.123 2222\n\t"
"%s tap0 vpn.example.org 5555\n\n",
argv[0], argv[0], argv[0]);
exit(1);
}
if (strlen(argv[1]) + 1 > IFNAMSIZ)
fputs("tap name is too long\n", stderr), exit(1);
tmp = 0;
do { /* dns, ip/port str to num */
res = getaddrinfo(argv[2], argv[3], NULL, &srvi);
tmp++;
usleep(10000); /* 10 ms */
} while (res == EAI_AGAIN && tmp < 5);
if (res){
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(res));
exit(1);
}
/* server address */
switch (srvi->ai_family){
case AF_INET:
memcpy(&srv, srvi->ai_addr, sizeof(struct sockaddr_in));
break;
case AF_INET6:
memcpy(&srv, srvi->ai_addr, sizeof(struct sockaddr_in6));
break;
default:
fprintf(stderr, "unsupported addrfamily: %s\n", argv[2]);
exit(1);
}
if (password[0] == 0){
/* TODO: check std streams redirected to file */
/* get term attrs */
res = tcgetattr(STDOUT_FILENO, &attr);
ERRDIE(res, "tcgetattr");
/* echo off */
attr.c_lflag &= ~ECHO;
res = tcsetattr(STDOUT_FILENO, TCSANOW, &attr);
ERRDIE(res, "tcsetattr");
/* get password */
fputs("Password: ", stdout), fflush(stdout);
pkt = fgets(password, PASSWORD_BUF_SZ, stdin);
fputs("\n", stdout);
if (pkt == NULL)
fputs("can't read password\n", stderr), exit(1);
/* echo on */
attr.c_lflag |= ECHO;
res = tcsetattr(STDOUT_FILENO, TCSANOW, &attr);
ERRDIE(res, "tcsetattr");
}
/* password without '\r\n' */
res = 0;
while (password[res] != '\0'
&& password[res] != '\r'
&& password[res] != '\n') res++;
/* hash password */
sponge256_hash32(key, password, res);
memset(password, 0, PASSWORD_BUF_SZ);
/* feed prng with key and current time */
duplex257_prng_feed(prng_state, ((u32*)key)[0]);
duplex257_prng_feed(prng_state, ((u32*)key)[1]);
duplex257_prng_feed(prng_state, ((u32*)key)[2]);
duplex257_prng_feed(prng_state, ((u32*)key)[3]);
duplex257_prng_feed(prng_state, ((u32*)key)[4]);
duplex257_prng_feed(prng_state, ((u32*)key)[5]);
duplex257_prng_feed(prng_state, ((u32*)key)[6]);
duplex257_prng_feed(prng_state, ((u32*)key)[7]);
clock_gettime(CLOCK_MONOTONIC, &t);
duplex257_prng_feed(prng_state, (u32)t.tv_sec);
duplex257_prng_feed(prng_state, (u32)t.tv_nsec);
lptime = (u32)t.tv_sec;
/* daemonize: redirect std streams */
res = open("/dev/null", O_RDONLY); ERRDIE(res, "open");
close(STDIN_FILENO), dup(res), close(res);
res = open(LOGFILE, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR);
ERRDIE(res, "open");
close(STDOUT_FILENO);
close(STDERR_FILENO);
dup(res), dup(res), close(res);
/* daemonize: fork 1 */
res = fork(); ERRDIE(res, "fork 1");
if (res != 0) exit(0);
/* daemonize: become session leader */
setsid();
/* daemonize: fork 2 */
res = fork(); ERRDIE(res, "fork 2");
if (res != 0) exit(0); /* kill session leader */
/* daemonized! */
/* cur pkt buf */
pkt = malloc(MAX_PKT_SZ);
if (pkt == NULL) fputs("pkt = malloc() failed\n",stderr), exit(1);
/* socket, setsockopt */
skt = socket(srv.ss_family, SOCK_DGRAM, 0); ERRDIE(skt, "socket");
res = 1;
res = setsockopt(skt, SOL_SOCKET, SO_REUSEADDR, &res, sizeof(res));
ERRDIE(res, "SO_REUSEADDR");
/* tap */
tap = open("/dev/net/tun", O_RDWR);
ERRDIE(tap, "/dev/net/tun");
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, argv[1], IFNAMSIZ);
res = ioctl(tap, TUNSETIFF, &ifr);
ERRDIE(res, "TUNSETIFF");
fdmax = (tap > skt) ? tap+1 : skt+1;
inf_loop:
/* select */
FD_ZERO(&rset);
FD_SET(skt, &rset);
FD_SET(tap, &rset);
slp.tv_sec = 0;
slp.tv_usec = 50000;
select(fdmax, &rset, NULL, NULL, &slp);
clock_gettime(CLOCK_MONOTONIC, &t);
if (TIMEOUT_P <= (u32)t.tv_sec - lptime){
/* ping for NAT keepalive */
send_pkt(skt, pkt, 14, &srv);
lptime = t.tv_sec;
}
/* read packet from tap */
if (FD_ISSET(tap, &rset)){
res = read(tap, pkt, MAX_PKT_SZ);
ERRDIE(res, "read(tap)");
/* TODO: check res+N > MAX_PKT_SZ */
send_pkt(skt, pkt, res, &srv);
}
/* recv packet from server */
if (0 == FD_ISSET(skt, &rset)) goto inf_loop;
res = recv_pkt(skt, pkt, MAX_PKT_SZ, &sender);
if (res < 14) goto inf_loop; /* ignore too small packets */
/* compare port and ip */
switch (srvi->ai_family){
case AF_INET:
if (((struct sockaddr_in*)&srv)->sin_port !=
((struct sockaddr_in*)&sender)->sin_port) goto inf_loop;
tmp = memcmp(&((struct sockaddr_in*)&srv)->sin_addr.s_addr,
&((struct sockaddr_in*)&sender)->sin_addr.s_addr,
4);
break;
case AF_INET6:
if (((struct sockaddr_in6*)&srv)->sin6_port !=
((struct sockaddr_in6*)&sender)->sin6_port) goto inf_loop;
tmp = memcmp(((struct sockaddr_in6*)&srv)->sin6_addr.s6_addr,
((struct sockaddr_in6*)&sender)->sin6_addr.s6_addr,
16);
break;
}
if (tmp != 0) goto inf_loop;
/* packet recv time for entropy and last packet time */
clock_gettime(CLOCK_MONOTONIC, &t);
duplex257_prng_feed(prng_state, t.tv_nsec);
lptime = t.tv_sec;
tmp = write(tap, pkt, res);
if (tmp < res)
fprintf(stderr, "tmp < res, tmp=%d, res=%d\n", tmp, res),
exit(1);
goto inf_loop;
return 0;
}
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