gvpe/src/vpn_tcp.C

/*
    vpn_tcp.C -- handle the tcp part of the protocol.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "config.h"

#if ENABLE_TCP

// tcp processing is extremely ugly, since the vpe protocol is simply
// designed for unreliable datagram networks. tcp is implemented by
// multiplexing packets over tcp. errors are completely ignored, as we
// rely on the higher level protocol to time out and reconnect.

#include <cstring>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/uio.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>

#include <map>

#include "netcompat.h"

#include "vpn.h"

#if ENABLE_HTTP_PROXY
# include "conf.h"
#endif

struct tcp_connection;

struct lt_sockinfo
{
  bool operator()(const sockinfo *a, const sockinfo *b) const
  {
    return *a < *b;
  }
};

struct tcp_si_map : public map<const sockinfo *, tcp_connection *, lt_sockinfo> {
  void cleaner_cb (time_watcher &w); time_watcher cleaner;

  tcp_si_map ()
    : cleaner(this, &tcp_si_map::cleaner_cb)
    {
      cleaner.start (0);
    }
} tcp_si;

struct tcp_connection : io_watcher {
  tstamp last_activity;
  const sockinfo si;
  vpn &v;
  bool active; // this connection has been actively established
  enum { ERROR, IDLE, CONNECTING, CONNECTING_PROXY, ESTABLISHED } state;

  vpn_packet *r_pkt;
  u32 r_len, r_ofs;

  vpn_packet *w_pkt;
  u32 w_len, w_ofs;

#if ENABLE_HTTP_PROXY
  char *proxy_req;
  int proxy_req_len;
#endif

  void tcpv4_ev (io_watcher &w, short revents);

  bool send_packet (vpn_packet *pkt, int tos);
  bool write_packet ();

  void error (); // abort conenction && cleanup

  operator tcp_si_map::value_type()
    {
      return tcp_si_map::value_type (&si, this);
    }

  tcp_connection (int fd_, const sockinfo &si_, vpn &v_);
  ~tcp_connection ();
};

void tcp_si_map::cleaner_cb (time_watcher &w)
{
  w.at = NOW + 600;
  tstamp to = NOW - ::conf.keepalive - 30 - 60;

  for (iterator i = begin (); i != end(); )
    if (i->second->last_activity >= to)
      ++i;
    else
      {
        erase (i);
        i = begin ();
      }
}

void
vpn::tcpv4_ev (io_watcher &w, short revents)
{
  if (revents & (POLLIN | POLLERR))
    {
      struct sockaddr_in sa;
      socklen_t sa_len = sizeof (sa);
      int len;

      int fd = accept (w.fd, (sockaddr *)&sa, &sa_len);

      if (fd >= 0)
        {
          sockinfo si(sa, PROT_TCPv4);

          slog (L_DEBUG, _("%s: accepted tcp connection"), (const char *)si);//D

          fcntl (fd, F_SETFL, O_NONBLOCK);

          tcp_connection *i = new tcp_connection (fd, si, *this);
          tcp_si.insert (*i);
        }
    }
}

bool
vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
{
  tcp_si_map::iterator info = tcp_si.find (&si);

  tcp_connection *i;

  if (info == tcp_si.end ())
    {
      i = new tcp_connection (-1, si, *this);
      tcp_si.insert (*i);
    }
  else
    i = info->second;

  return i->send_packet (pkt, tos);
}

bool
tcp_connection::write_packet ()
{
  ssize_t len;

  if (w_ofs < 2)
    {
      u16 plen = htons (w_pkt->len);

      iovec vec[2];
      //TODO: char* is the right type? hardly...
      vec[0].iov_base = (char *)((u8 *)&plen) + w_ofs;
      vec[0].iov_len = 2 - w_ofs;
      vec[1].iov_base = (char *)&((*w_pkt)[0]);
      vec[1].iov_len = w_len - 2;

      len = writev (fd, vec, 2);
    }
  else
    len = write (fd, &((*w_pkt)[w_ofs - 2]), w_len);

  if (len > 0)
    {
      w_ofs += len;
      w_len -= len;

      return w_len == 0;
    }
  else if (len < 0 && (errno == EAGAIN || errno == EINTR))
    return false;
  else
    {
      error ();
      return false;
    }
}

void
tcp_connection::tcpv4_ev (io_watcher &w, short revents)
{
  last_activity = NOW;

  if (revents & (POLLERR | POLLHUP))
    {
      error ();
      return;
    }

  if (revents & POLLOUT)
    {
      if (state == CONNECTING)
        {
          state = ESTABLISHED;
          set (POLLIN);
#if ENABLE_HTTP_PROXY
          if (::conf.proxy_host && ::conf.proxy_port)
            {
              state = CONNECTING_PROXY;
              write (fd, proxy_req, proxy_req_len);
              free (proxy_req); proxy_req = 0;
            }
#endif
        }
      else if (state == ESTABLISHED)
        {
          if (w_pkt)
            {
              if (write_packet ())
                {
                  delete w_pkt; w_pkt = 0;

                  set (POLLIN);
                }
            }
          else
            set (POLLIN);
        }
      else
        set (POLLIN);
    }

  if (revents & POLLIN)
    {
      if (state == ESTABLISHED)
        for (;;)
          {
            if (!r_pkt)
              {
                r_pkt = new vpn_packet;
                r_ofs = 0;
                r_len = 2; // header
              }

            ssize_t len = read (fd, &((*r_pkt)[r_ofs < 2 ? r_ofs : r_ofs - 2]), r_len);

            if (len > 0)
              {
                r_len -= len;
                r_ofs += len;

                if (r_len == 0)
                  {
                    if (r_ofs == 2)
                      {
                        r_len = ntohs (*(u16 *)&((*r_pkt)[0]));
                        r_pkt->len = r_len;

                        if (r_len > 0 && r_len < MAXSIZE)
                          continue;
                      }
                    else
                      {
                        v.recv_vpn_packet (r_pkt, si);
                        delete r_pkt;
                        r_pkt = 0;

                        continue;
                      }
                  }
                else
                  break;
              }
            else if (len < 0 && (errno == EINTR || errno == EAGAIN))
              break;

            error ();
            break;
          }
#if ENABLE_HTTP_PROXY
      else if (state == CONNECTING_PROXY)
        {
          fcntl (fd, F_SETFL, 0);
          char r[1024];
          int i;
          bool emptyline = false;

          // we do a blocking read of the response, to hell with it
          for (i = 0; i < 1023; i++)
            {
              int l = read (fd, &r[i], 1);

              if (l <= 0)
                {
                  error ();
                  return;
                }

              if (r[i] == '\012')
                {
                  if (emptyline)
                    break;
                  else
                    emptyline = true;
                }
              else if (r[i] != '\015')
                emptyline = false;
            }

          fcntl (fd, F_SETFL, O_NONBLOCK);

          if (i < 12)
            {
              slog (L_ERR, _("(%s): unable to do proxy-forwarding, short response"),
                    (const char *)si);
              error ();
            }
          else if (r[0] != 'H' || r[1] != 'T' || r[2] != 'T' || r[3] != 'P' || r[4] != '/'
                   || r[5] != '1' // http-major
                   || r[9] != '2') // response
            {
              slog (L_ERR, _("(%s): malformed or unexpected proxy response (%.12s)"),
                    (const char *)si, r);
              error ();
            }
          else
            state = ESTABLISHED;
        }
#endif
    }
}

bool
tcp_connection::send_packet (vpn_packet *pkt, int tos)
{
  last_activity = NOW;

  if (state == IDLE)
    {
      // woaw, the first lost packet ;)
      fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);

      if (fd >= 0)
        {
          const sockinfo *csi = &si;

#if ENABLE_HTTP_PROXY
          sockinfo psi;

          if (::conf.proxy_host && ::conf.proxy_port)
            {
              psi.set (::conf.proxy_host, ::conf.proxy_port, PROT_TCPv4);

              if (psi.valid ())
                {
                  csi = &psi;

                  proxy_req_len = asprintf (&proxy_req,
                                            "CONNECT %s:%d HTTP/1.0\015\012"
                                            "%s%s%s" // optional proxy-auth
                                            "\015\012",
                                            si.ntoa (),
                                            ntohs (si.port),
                                            ::conf.proxy_auth ? "Proxy-Authorization: Basic " : "",
                                            ::conf.proxy_auth ? ::conf.proxy_auth             : "",
                                            ::conf.proxy_auth ? "\015\012"                    : "");

                }
              else
                slog (L_ERR, _("unable to resolve http proxy hostname '%s', trying direct"),
                      ::conf.proxy_host);
            }
#endif
          
          fcntl (fd, F_SETFL, O_NONBLOCK);

          if (connect (fd, csi->sav4 (), csi->salenv4 ()) >= 0
              || errno == EINPROGRESS)
            {
              state = CONNECTING;
              start (fd, POLLOUT);
            }
          else
            close (fd);
        }
    }
  else if (state == ESTABLISHED)
    {
      // drop packet if the tcp write buffer is full. this *is* the
      // right thing to do, not using tcp *is* the right thing to do.
      if (!w_pkt)
        {
          // how this maps to the underlying tcp packets we don't know
          // and we don't care. at least we tried ;)
#if defined(SOL_IP) && defined(IP_TOS)
          setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);
#endif

          w_pkt = pkt;
          w_ofs = 0;
          w_len = pkt->len + 2; // length + size header

          if (write_packet ())
            w_pkt = 0;
          else
            {
              w_pkt = new vpn_packet;
              w_pkt->set (*pkt);

              set (POLLIN | POLLOUT);
            }
        }
    }

  return state != ERROR;
}

void tcp_connection::error ()
{
  if (fd >= 0)
    {
      close (fd);
      fd = -1;
    }

  delete r_pkt; r_pkt = 0;
  delete w_pkt; w_pkt = 0;
#if ENABLE_HTTP_PROXY
  free (proxy_req); proxy_req = 0;
#endif

  stop ();
  state = active ? IDLE : ERROR;
}

tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_)
: v(v_), si(si_), io_watcher(this, &tcp_connection::tcpv4_ev)
{
  last_activity = NOW;
  r_pkt = 0;
  w_pkt = 0;
  fd = fd_;
#if ENABLE_HTTP_PROXY
  proxy_req = 0;
#endif

  if (fd < 0)
    {
      active = true;
      state = IDLE;
    }
  else
    {
      active = false;
      state = ESTABLISHED;
      start (fd, POLLIN);
    }
}

tcp_connection::~tcp_connection ()
{
  error ();
}

#endif

Revision:	1.9
Committed:	Wed Oct 15 00:41:59 2003 UTC (20 years, 7 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.8:	+1 -4 lines
Log Message:	* empty log message *
#	Content
1	/*
2	vpn_tcp.C -- handle the tcp part of the protocol.
3
4	This program is free software; you can redistribute it and/or modify
5	it under the terms of the GNU General Public License as published by
6	the Free Software Foundation; either version 2 of the License, or
7	(at your option) any later version.
8
9	This program is distributed in the hope that it will be useful,
10	but WITHOUT ANY WARRANTY; without even the implied warranty of
11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12	GNU General Public License for more details.
13
14	You should have received a copy of the GNU General Public License
15	along with this program; if not, write to the Free Software
16	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17	*/
18
19	#include "config.h"
20
21	#if ENABLE_TCP
22
23	// tcp processing is extremely ugly, since the vpe protocol is simply
24	// designed for unreliable datagram networks. tcp is implemented by
25	// multiplexing packets over tcp. errors are completely ignored, as we
26	// rely on the higher level protocol to time out and reconnect.
27
28	#include <cstring>
29
30	#include <sys/types.h>
31	#include <sys/socket.h>
32	#include <sys/wait.h>
33	#include <sys/uio.h>
34	#include <errno.h>
35	#include <time.h>
36	#include <unistd.h>
37	#include <fcntl.h>
38
39	#include <map>
40
41	#include "netcompat.h"
42
43	#include "vpn.h"
44
45	#if ENABLE_HTTP_PROXY
46	# include "conf.h"
47	#endif
48
49	struct tcp_connection;
50
51	struct lt_sockinfo
52	{
53	bool operator()(const sockinfo a, const sockinfo b) const
54	{
55	return a < b;
56	}
57	};
58
59	struct tcp_si_map : public map<const sockinfo , tcp_connection , lt_sockinfo> {
60	void cleaner_cb (time_watcher &w); time_watcher cleaner;
61
62	tcp_si_map ()
63	: cleaner(this, &tcp_si_map::cleaner_cb)
64	{
65	cleaner.start (0);
66	}
67	} tcp_si;
68
69	struct tcp_connection : io_watcher {
70	tstamp last_activity;
71	const sockinfo si;
72	vpn &v;
73	bool active; // this connection has been actively established
74	enum { ERROR, IDLE, CONNECTING, CONNECTING_PROXY, ESTABLISHED } state;
75
76	vpn_packet *r_pkt;
77	u32 r_len, r_ofs;
78
79	vpn_packet *w_pkt;
80	u32 w_len, w_ofs;
81
82	#if ENABLE_HTTP_PROXY
83	char *proxy_req;
84	int proxy_req_len;
85	#endif
86
87	void tcpv4_ev (io_watcher &w, short revents);
88
89	bool send_packet (vpn_packet *pkt, int tos);
90	bool write_packet ();
91
92	void error (); // abort conenction && cleanup
93
94	operator tcp_si_map::value_type()
95	{
96	return tcp_si_map::value_type (&si, this);
97	}
98
99	tcp_connection (int fd_, const sockinfo &si_, vpn &v_);
100	~tcp_connection ();
101	};
102
103	void tcp_si_map::cleaner_cb (time_watcher &w)
104	{
105	w.at = NOW + 600;
106	tstamp to = NOW - ::conf.keepalive - 30 - 60;
107
108	for (iterator i = begin (); i != end(); )
109	if (i->second->last_activity >= to)
110	++i;
111	else
112	{
113	erase (i);
114	i = begin ();
115	}
116	}
117
118	void
119	vpn::tcpv4_ev (io_watcher &w, short revents)
120	{
121	if (revents & (POLLIN \| POLLERR))
122	{
123	struct sockaddr_in sa;
124	socklen_t sa_len = sizeof (sa);
125	int len;
126
127	int fd = accept (w.fd, (sockaddr *)&sa, &sa_len);
128
129	if (fd >= 0)
130	{
131	sockinfo si(sa, PROT_TCPv4);
132
133	slog (L_DEBUG, _("%s: accepted tcp connection"), (const char *)si);//D
134
135	fcntl (fd, F_SETFL, O_NONBLOCK);
136
137	tcp_connection i = new tcp_connection (fd, si, this);
138	tcp_si.insert (*i);
139	}
140	}
141	}
142
143	bool
144	vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
145	{
146	tcp_si_map::iterator info = tcp_si.find (&si);
147
148	tcp_connection *i;
149
150	if (info == tcp_si.end ())
151	{
152	i = new tcp_connection (-1, si, *this);
153	tcp_si.insert (*i);
154	}
155	else
156	i = info->second;
157
158	return i->send_packet (pkt, tos);
159	}
160
161	bool
162	tcp_connection::write_packet ()
163	{
164	ssize_t len;
165
166	if (w_ofs < 2)
167	{
168	u16 plen = htons (w_pkt->len);
169
170	iovec vec[2];
171	//TODO: char* is the right type? hardly...
172	vec[0].iov_base = (char )((u8 )&plen) + w_ofs;
173	vec[0].iov_len = 2 - w_ofs;
174	vec[1].iov_base = (char )&((w_pkt)[0]);
175	vec[1].iov_len = w_len - 2;
176
177	len = writev (fd, vec, 2);
178	}
179	else
180	len = write (fd, &((*w_pkt)[w_ofs - 2]), w_len);
181
182	if (len > 0)
183	{
184	w_ofs += len;
185	w_len -= len;
186
187	return w_len == 0;
188	}
189	else if (len < 0 && (errno == EAGAIN \|\| errno == EINTR))
190	return false;
191	else
192	{
193	error ();
194	return false;
195	}
196	}
197
198	void
199	tcp_connection::tcpv4_ev (io_watcher &w, short revents)
200	{
201	last_activity = NOW;
202
203	if (revents & (POLLERR \| POLLHUP))
204	{
205	error ();
206	return;
207	}
208
209	if (revents & POLLOUT)
210	{
211	if (state == CONNECTING)
212	{
213	state = ESTABLISHED;
214	set (POLLIN);
215	#if ENABLE_HTTP_PROXY
216	if (::conf.proxy_host && ::conf.proxy_port)
217	{
218	state = CONNECTING_PROXY;
219	write (fd, proxy_req, proxy_req_len);
220	free (proxy_req); proxy_req = 0;
221	}
222	#endif
223	}
224	else if (state == ESTABLISHED)
225	{
226	if (w_pkt)
227	{
228	if (write_packet ())
229	{
230	delete w_pkt; w_pkt = 0;
231
232	set (POLLIN);
233	}
234	}
235	else
236	set (POLLIN);
237	}
238	else
239	set (POLLIN);
240	}
241
242	if (revents & POLLIN)
243	{
244	if (state == ESTABLISHED)
245	for (;;)
246	{
247	if (!r_pkt)
248	{
249	r_pkt = new vpn_packet;
250	r_ofs = 0;
251	r_len = 2; // header
252	}
253
254	ssize_t len = read (fd, &((*r_pkt)[r_ofs < 2 ? r_ofs : r_ofs - 2]), r_len);
255
256	if (len > 0)
257	{
258	r_len -= len;
259	r_ofs += len;
260
261	if (r_len == 0)
262	{
263	if (r_ofs == 2)
264	{
265	r_len = ntohs ((u16 )&((*r_pkt)[0]));
266	r_pkt->len = r_len;
267
268	if (r_len > 0 && r_len < MAXSIZE)
269	continue;
270	}
271	else
272	{
273	v.recv_vpn_packet (r_pkt, si);
274	delete r_pkt;
275	r_pkt = 0;
276
277	continue;
278	}
279	}
280	else
281	break;
282	}
283	else if (len < 0 && (errno == EINTR \|\| errno == EAGAIN))
284	break;
285
286	error ();
287	break;
288	}
289	#if ENABLE_HTTP_PROXY
290	else if (state == CONNECTING_PROXY)
291	{
292	fcntl (fd, F_SETFL, 0);
293	char r[1024];
294	int i;
295	bool emptyline = false;
296
297	// we do a blocking read of the response, to hell with it
298	for (i = 0; i < 1023; i++)
299	{
300	int l = read (fd, &r[i], 1);
301
302	if (l <= 0)
303	{
304	error ();
305	return;
306	}
307
308	if (r[i] == '\012')
309	{
310	if (emptyline)
311	break;
312	else
313	emptyline = true;
314	}
315	else if (r[i] != '\015')
316	emptyline = false;
317	}
318
319	fcntl (fd, F_SETFL, O_NONBLOCK);
320
321	if (i < 12)
322	{
323	slog (L_ERR, _("(%s): unable to do proxy-forwarding, short response"),
324	(const char *)si);
325	error ();
326	}
327	else if (r[0] != 'H' \|\| r[1] != 'T' \|\| r[2] != 'T' \|\| r[3] != 'P' \|\| r[4] != '/'
328	\|\| r[5] != '1' // http-major
329	\|\| r[9] != '2') // response
330	{
331	slog (L_ERR, _("(%s): malformed or unexpected proxy response (%.12s)"),
332	(const char *)si, r);
333	error ();
334	}
335	else
336	state = ESTABLISHED;
337	}
338	#endif
339	}
340	}
341
342	bool
343	tcp_connection::send_packet (vpn_packet *pkt, int tos)
344	{
345	last_activity = NOW;
346
347	if (state == IDLE)
348	{
349	// woaw, the first lost packet ;)
350	fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
351
352	if (fd >= 0)
353	{
354	const sockinfo *csi = &si;
355
356	#if ENABLE_HTTP_PROXY
357	sockinfo psi;
358
359	if (::conf.proxy_host && ::conf.proxy_port)
360	{
361	psi.set (::conf.proxy_host, ::conf.proxy_port, PROT_TCPv4);
362
363	if (psi.valid ())
364	{
365	csi = ψ
366
367	proxy_req_len = asprintf (&proxy_req,
368	"CONNECT %s:%d HTTP/1.0\015\012"
369	"%s%s%s" // optional proxy-auth
370	"\015\012",
371	si.ntoa (),
372	ntohs (si.port),
373	::conf.proxy_auth ? "Proxy-Authorization: Basic " : "",
374	::conf.proxy_auth ? ::conf.proxy_auth : "",
375	::conf.proxy_auth ? "\015\012" : "");
376
377	}
378	else
379	slog (L_ERR, _("unable to resolve http proxy hostname '%s', trying direct"),
380	::conf.proxy_host);
381	}
382	#endif
383
384	fcntl (fd, F_SETFL, O_NONBLOCK);
385
386	if (connect (fd, csi->sav4 (), csi->salenv4 ()) >= 0
387	\|\| errno == EINPROGRESS)
388	{
389	state = CONNECTING;
390	start (fd, POLLOUT);
391	}
392	else
393	close (fd);
394	}
395	}
396	else if (state == ESTABLISHED)
397	{
398	// drop packet if the tcp write buffer is full. this is the
399	// right thing to do, not using tcp is the right thing to do.
400	if (!w_pkt)
401	{
402	// how this maps to the underlying tcp packets we don't know
403	// and we don't care. at least we tried ;)
404	#if defined(SOL_IP) && defined(IP_TOS)
405	setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);
406	#endif
407
408	w_pkt = pkt;
409	w_ofs = 0;
410	w_len = pkt->len + 2; // length + size header
411
412	if (write_packet ())
413	w_pkt = 0;
414	else
415	{
416	w_pkt = new vpn_packet;
417	w_pkt->set (*pkt);
418
419	set (POLLIN \| POLLOUT);
420	}
421	}
422	}
423
424	return state != ERROR;
425	}
426
427	void tcp_connection::error ()
428	{
429	if (fd >= 0)
430	{
431	close (fd);
432	fd = -1;
433	}
434
435	delete r_pkt; r_pkt = 0;
436	delete w_pkt; w_pkt = 0;
437	#if ENABLE_HTTP_PROXY
438	free (proxy_req); proxy_req = 0;
439	#endif
440
441	stop ();
442	state = active ? IDLE : ERROR;
443	}
444
445	tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_)
446	: v(v_), si(si_), io_watcher(this, &tcp_connection::tcpv4_ev)
447	{
448	last_activity = NOW;
449	r_pkt = 0;
450	w_pkt = 0;
451	fd = fd_;
452	#if ENABLE_HTTP_PROXY
453	proxy_req = 0;
454	#endif
455
456	if (fd < 0)
457	{
458	active = true;
459	state = IDLE;
460	}
461	else
462	{
463	active = false;
464	state = ESTABLISHED;
465	start (fd, POLLIN);
466	}
467	}
468
469	tcp_connection::~tcp_connection ()
470	{
471	error ();
472	}
473
474	#endif
475