static void connect_handler(nsock_pool nsp, nsock_event evt, void *data)
{
enum nse_status status = nse_status(evt);
enum nse_type type = nse_type(evt);
assert(type == NSE_TYPE_CONNECT || type == NSE_TYPE_CONNECT_SSL);
if (status == NSE_STATUS_ERROR) {
loguser("%s.\n", socket_strerror(nse_errorcode(evt)));
exit(1);
} else if (status == NSE_STATUS_TIMEOUT) {
loguser("%s.\n", socket_strerror(ETIMEDOUT));
exit(1);
} else {
assert(status == NSE_STATUS_SUCCESS);
}
#ifdef HAVE_OPENSSL
if (nsi_checkssl(cs.sock_nsi)) {
/* Check the domain name. ssl_post_connect_check prints an
error message if appropriate. */
if (!ssl_post_connect_check((SSL *) nsi_getssl(cs.sock_nsi), o.target))
bye("Certificate verification error.");
}
#endif
connect_report(cs.sock_nsi);
/* Create IOD for nsp->stdin */
if ((cs.stdin_nsi = nsi_new2(nsp, 0, NULL)) == NULL)
bye("Failed to create stdin nsiod.");
post_connect(nsp, nse_iod(evt));
}
void telnet_event_handler(nsock_pool nsp, nsock_event nse, void *mydata) {
nsock_iod nsi = nse_iod(nse);
enum nse_status status = nse_status(nse);
enum nse_type type = nse_type(nse);
struct sockaddr_in peer;
struct telnet_state *ts;
int nbytes;
char *str;
int read_timeout = -1;
int write_timeout = 2000;
ts = (struct telnet_state *)mydata;
printf("telnet_event_handler: Received callback of type %s with status %s\n", nse_type2str(type), nse_status2str(status));
if (status == NSE_STATUS_SUCCESS) {
switch (type) {
case NSE_TYPE_CONNECT:
case NSE_TYPE_CONNECT_SSL:
nsi_getlastcommunicationinfo(nsi, NULL, NULL, NULL, (struct sockaddr *)&peer, sizeof peer);
printf("Successfully connected %sto %s:%hu -- start typing lines\n", (type == NSE_TYPE_CONNECT_SSL) ? "(SSL!) " : "", inet_ntoa(peer.sin_addr), peer.sin_port);
/* First of all, lets add STDIN to our list of watched filehandles */
if ((ts->stdin_nsi = nsi_new2(nsp, STDIN_FILENO, NULL)) == NULL) {
fprintf(stderr, "Failed to create stdin msi\n");
exit(1);
}
/* Now lets read from stdin and the network, line buffered (by nsock) */
ts->latest_readtcpev = nsock_readlines(nsp, ts->tcp_nsi, telnet_event_handler, read_timeout, ts, 1);
ts->latest_readstdinev = nsock_readlines(nsp, ts->stdin_nsi, telnet_event_handler, read_timeout, ts, 1);
break;
case NSE_TYPE_READ:
str = nse_readbuf(nse, &nbytes);
if (nsi == ts->tcp_nsi) {
printf("%s", str);
/* printf("Read from tcp socket (%d bytes):\n%s", nbytes, str); */
ts->latest_readtcpev = nsock_readlines(nsp, ts->tcp_nsi, telnet_event_handler, read_timeout, ts, 1);
} else {
/* printf("Read from stdin (%d bytes):\n%s", nbytes, str); */
nsock_write(nsp, ts->tcp_nsi, telnet_event_handler, write_timeout, ts, str, nbytes);
ts->latest_readstdinev = nsock_readlines(nsp, ts->stdin_nsi, telnet_event_handler, read_timeout, ts, 1);
}
break;
case NSE_TYPE_WRITE:
/* Nothing to do, really */
break;
case NSE_TYPE_TIMER:
break;
default:
fprintf(stderr, "telnet_event_handler: Got bogus type -- quitting\n");
exit(1);
break;
}
} else if (status == NSE_STATUS_EOF) {
printf("Got EOF from %s\nCancelling outstanding readevents.\n", (nsi == ts->tcp_nsi) ? "tcp socket" : "stdin");
/* One of these is the event I am currently handling! But I wanted to
be evil when testing this out... */
if (nsock_event_cancel(nsp, ts->latest_readtcpev, 1) != 0) {
printf("Cancelled tcp event: %li\n", ts->latest_readtcpev);
}
if (nsock_event_cancel(nsp, ts->latest_readstdinev, 1) != 0) {
printf("Cancelled stdin event: %li\n", ts->latest_readstdinev);
}
} else if (status == NSE_STATUS_ERROR) {
if (nsi_checkssl(nsi)) {
printf("SSL %s failed: %s\n", nse_type2str(type), ERR_error_string(ERR_get_error(), NULL));
} else {
int err;
err = nse_errorcode(nse);
printf("%s failed: (%d) %s\n", nse_type2str(type), err, strerror(err));
}
}
return;
}
int ncat_connect(void)
{
nsock_pool mypool;
int rc;
/* Unless explicitely asked not to do so, ncat uses the
* fallback nsock engine to maximize compatibility between
* operating systems and the different use cases.
*/
if (!o.nsock_engine)
nsock_set_default_engine("select");
/* Create an nsock pool */
if ((mypool = nsp_new(NULL)) == NULL)
bye("Failed to create nsock_pool.");
if (o.debug >= 6)
nsock_set_loglevel(mypool, NSOCK_LOG_DBG_ALL);
else if (o.debug >= 3)
nsock_set_loglevel(mypool, NSOCK_LOG_DBG);
else if (o.debug >= 1)
nsock_set_loglevel(mypool, NSOCK_LOG_INFO);
else
nsock_set_loglevel(mypool, NSOCK_LOG_ERROR);
/* Allow connections to broadcast addresses. */
nsp_setbroadcast(mypool, 1);
#ifdef HAVE_OPENSSL
set_ssl_ctx_options((SSL_CTX *) nsp_ssl_init(mypool));
#endif
if (httpconnect.storage.ss_family == AF_UNSPEC
&& socksconnect.storage.ss_family == AF_UNSPEC) {
/* A non-proxy connection. Create an iod for a new socket. */
cs.sock_nsi = nsi_new(mypool, NULL);
if (cs.sock_nsi == NULL)
bye("Failed to create nsock_iod.");
if (nsi_set_hostname(cs.sock_nsi, o.target) == -1)
bye("Failed to set hostname on iod.");
#if HAVE_SYS_UN_H
/* For DGRAM UNIX socket we have to use source socket */
if (o.af == AF_UNIX && o.udp)
{
if (srcaddr.storage.ss_family != AF_UNIX) {
char *tmp_name = NULL;
/* If no source socket was specified, we have to create temporary one. */
if ((tmp_name = tempnam(NULL, "ncat.")) == NULL)
bye("Failed to create name for temporary DGRAM source Unix domain socket (tempnam).");
srcaddr.un.sun_family = AF_UNIX;
strncpy(srcaddr.un.sun_path, tmp_name, sizeof(srcaddr.un.sun_path));
free (tmp_name);
}
nsi_set_localaddr(cs.sock_nsi, &srcaddr.storage, SUN_LEN((struct sockaddr_un *)&srcaddr.storage));
if (o.verbose)
loguser("[%s] used as source DGRAM Unix domain socket.\n", srcaddr.un.sun_path);
}
else
#endif
if (srcaddr.storage.ss_family != AF_UNSPEC)
nsi_set_localaddr(cs.sock_nsi, &srcaddr.storage, sizeof(srcaddr.storage));
if (o.numsrcrtes) {
unsigned char *ipopts = NULL;
size_t ipoptslen = 0;
if (o.af != AF_INET)
bye("Sorry, -g can only currently be used with IPv4.");
ipopts = buildsrcrte(targetss.in.sin_addr, o.srcrtes, o.numsrcrtes, o.srcrteptr, &ipoptslen);
nsi_set_ipoptions(cs.sock_nsi, ipopts, ipoptslen);
free(ipopts); /* Nsock has its own copy */
}
#if HAVE_SYS_UN_H
if (o.af == AF_UNIX) {
if (o.udp) {
nsock_connect_unixsock_datagram(mypool, cs.sock_nsi, connect_handler, NULL,
&targetss.sockaddr,
SUN_LEN((struct sockaddr_un *)&targetss.sockaddr));
} else {
nsock_connect_unixsock_stream(mypool, cs.sock_nsi, connect_handler, o.conntimeout,
NULL, &targetss.sockaddr,
SUN_LEN((struct sockaddr_un *)&targetss.sockaddr));
}
} else
#endif
if (o.udp) {
nsock_connect_udp(mypool, cs.sock_nsi, connect_handler,
NULL, &targetss.sockaddr, targetsslen,
inet_port(&targetss));
}
#ifdef HAVE_OPENSSL
else if (o.sctp && o.ssl) {
nsock_connect_ssl(mypool, cs.sock_nsi, connect_handler,
o.conntimeout, NULL,
&targetss.sockaddr, targetsslen,
IPPROTO_SCTP, inet_port(&targetss),
NULL);
}
#endif
else if (o.sctp) {
nsock_connect_sctp(mypool, cs.sock_nsi, connect_handler,
o.conntimeout, NULL,
&targetss.sockaddr, targetsslen,
inet_port(&targetss));
}
#ifdef HAVE_OPENSSL
else if (o.ssl) {
nsock_connect_ssl(mypool, cs.sock_nsi, connect_handler,
o.conntimeout, NULL,
&targetss.sockaddr, targetsslen,
IPPROTO_TCP, inet_port(&targetss),
NULL);
}
#endif
else {
nsock_connect_tcp(mypool, cs.sock_nsi, connect_handler,
o.conntimeout, NULL,
&targetss.sockaddr, targetsslen,
inet_port(&targetss));
}
} else {
/* A proxy connection. */
static int connect_socket;
int len;
char *line;
size_t n;
if (httpconnect.storage.ss_family != AF_UNSPEC) {
connect_socket = do_proxy_http();
if (connect_socket == -1)
return 1;
} else if (socksconnect.storage.ss_family != AF_UNSPEC) {
struct socket_buffer stateful_buf;
struct socks4_data socks4msg;
char socksbuf[8];
connect_socket = do_connect(SOCK_STREAM);
if (connect_socket == -1) {
loguser("Proxy connection failed: %s.\n", socket_strerror(socket_errno()));
return 1;
}
socket_buffer_init(&stateful_buf, connect_socket);
if (o.verbose) {
loguser("Connected to proxy %s:%hu\n", inet_socktop(&targetss),
inet_port(&targetss));
}
/* Fill the socks4_data struct */
zmem(&socks4msg, sizeof(socks4msg));
socks4msg.version = SOCKS4_VERSION;
socks4msg.type = SOCKS_CONNECT;
socks4msg.port = socksconnect.in.sin_port;
socks4msg.address = socksconnect.in.sin_addr.s_addr;
if (o.proxy_auth)
Strncpy(socks4msg.username, (char *) o.proxy_auth, sizeof(socks4msg.username));
len = 8 + strlen(socks4msg.username) + 1;
if (send(connect_socket, (char *) &socks4msg, len, 0) < 0) {
loguser("Error sending proxy request: %s.\n", socket_strerror(socket_errno()));
return 1;
}
/* The size of the socks4 response is 8 bytes. So read exactly
8 bytes from the buffer */
if (socket_buffer_readcount(&stateful_buf, socksbuf, 8) < 0) {
loguser("Error: short reponse from proxy.\n");
return 1;
}
if (socksbuf[1] != 90) {
loguser("Proxy connection failed.\n");
return 1;
}
/* Clear out whatever is left in the socket buffer which may be
already sent by proxy server along with http response headers. */
line = socket_buffer_remainder(&stateful_buf, &n);
/* Write the leftover data to stdout. */
Write(STDOUT_FILENO, line, n);
}
/* Once the proxy negotiation is done, Nsock takes control of the
socket. */
cs.sock_nsi = nsi_new2(mypool, connect_socket, NULL);
/* Create IOD for nsp->stdin */
if ((cs.stdin_nsi = nsi_new2(mypool, 0, NULL)) == NULL)
bye("Failed to create stdin nsiod.");
post_connect(mypool, cs.sock_nsi);
}
/* connect */
rc = nsock_loop(mypool, -1);
if (o.verbose) {
struct timeval end_time;
double time;
gettimeofday(&end_time, NULL);
time = TIMEVAL_MSEC_SUBTRACT(end_time, start_time) / 1000.0;
loguser("%lu bytes sent, %lu bytes received in %.2f seconds.\n",
nsi_get_write_count(cs.sock_nsi),
nsi_get_read_count(cs.sock_nsi), time);
}
#if HAVE_SYS_UN_H
if (o.af == AF_UNIX && o.udp) {
if (o.verbose)
loguser("Deleting source DGRAM Unix domain socket. [%s]\n", srcaddr.un.sun_path);
unlink(srcaddr.un.sun_path);
}
#endif
nsp_delete(mypool);
return rc == NSOCK_LOOP_ERROR ? 1 : 0;
}
/* nsock_iod is like a "file descriptor" for the nsock library. You
use it to request events. And here is how you create an nsock_iod.
nsi_new returns NULL if the iod cannot be allocated. Pass NULL as
userdata if you don't want to immediately associate any user data
with the iod. */
nsock_iod nsi_new(nsock_pool nsockp, void *userdata) {
return nsi_new2(nsockp, -1, userdata);
}
