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/poll.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <sys/uio.h>
#include <arpa/inet.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>

#include <map>
#include <unistd.h>
#include <fcntl.h>
#include <sys/poll.h>

#include "vpn.h"

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, ESTABLISHED } state;

  vpn_packet *r_pkt;
  u32 r_len, r_ofs;

  vpn_packet *w_pkt;
  u32 w_len, w_ofs;

  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);
}

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

  delete r_pkt; r_pkt = 0;
  delete w_pkt; w_pkt = 0;

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

bool
tcp_connection::write_packet ()
{
  ssize_t len;

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

      iovec vec[2];
      vec[0].iov_base = ((u8 *)&plen) + w_ofs;
      vec[0].iov_len = 2 - w_ofs;
      vec[1].iov_base = &((*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);
        }
      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)
    {
      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;
        }
    }
}

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)
        {
          fcntl (fd, F_SETFL, O_NONBLOCK);
          
          if (connect (fd, si.sav4 (), si.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 ;)
          setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);

          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;
}

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

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

#endif

Revision:	1.3
Committed:	Sun Apr 6 20:01:53 2003 UTC (21 years, 1 month ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+96 -27 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1	/*
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/poll.h>
33			#include <sys/wait.h>
34			#include <netinet/in.h>
35			#include <sys/uio.h>
36			#include <arpa/inet.h>
37			#include <errno.h>
38			#include <time.h>
39			#include <unistd.h>
40
41			#include <map>
42			#include <unistd.h>
43			#include <fcntl.h>
44			#include <sys/poll.h>
45
46			#include "vpn.h"
47
48			struct tcp_connection;
49
50			struct lt_sockinfo
51			{
52			bool operator()(const sockinfo a, const sockinfo b) const
53			{
54			return a < b;
55			}
56			};
57
58			struct tcp_si_map : public map<const sockinfo , tcp_connection , lt_sockinfo> {
59			void cleaner_cb (time_watcher &w); time_watcher cleaner;
60
61			tcp_si_map ()
62			: cleaner(this, &tcp_si_map::cleaner_cb)
63			{
64			cleaner.start (0);
65			}
66			} tcp_si;
67
68			struct tcp_connection : io_watcher {
69			tstamp last_activity;
70			const sockinfo si;
71			vpn &v;
72			bool active; // this connection has been actively established
73			enum { ERROR, IDLE, CONNECTING, ESTABLISHED } state;
74
75			vpn_packet *r_pkt;
76			u32 r_len, r_ofs;
77
78	pcg	1.3	vpn_packet *w_pkt;
79			u32 w_len, w_ofs;
80
81	pcg	1.1	void tcpv4_ev (io_watcher &w, short revents);
82
83	pcg	1.2	bool send_packet (vpn_packet *pkt, int tos);
84	pcg	1.3	bool write_packet ();
85	pcg	1.1
86			void error (); // abort conenction && cleanup
87
88			operator tcp_si_map::value_type()
89			{
90			return tcp_si_map::value_type (&si, this);
91			}
92
93			tcp_connection (int fd_, const sockinfo &si_, vpn &v_);
94			~tcp_connection ();
95			};
96
97			void tcp_si_map::cleaner_cb (time_watcher &w)
98			{
99			w.at = NOW + 600;
100			tstamp to = NOW - ::conf.keepalive - 30 - 60;
101
102			for (iterator i = begin (); i != end(); )
103			if (i->second->last_activity >= to)
104			++i;
105			else
106			{
107			erase (i);
108			i = begin ();
109			}
110			}
111
112			void
113			vpn::tcpv4_ev (io_watcher &w, short revents)
114			{
115			if (revents & (POLLIN \| POLLERR))
116			{
117			struct sockaddr_in sa;
118			socklen_t sa_len = sizeof (sa);
119			int len;
120
121			int fd = accept (w.fd, (sockaddr *)&sa, &sa_len);
122
123			if (fd >= 0)
124			{
125			sockinfo si(sa, PROT_TCPv4);
126
127			slog (L_DEBUG, _("%s: accepted tcp connection"), (const char *)si);//D
128
129			fcntl (fd, F_SETFL, O_NONBLOCK);
130
131			tcp_connection i = new tcp_connection (fd, si, this);
132			tcp_si.insert (*i);
133			}
134			}
135			}
136
137	pcg	1.2	bool
138	pcg	1.1	vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
139			{
140			tcp_si_map::iterator info = tcp_si.find (&si);
141
142			tcp_connection *i;
143
144			if (info == tcp_si.end ())
145			{
146			i = new tcp_connection (-1, si, *this);
147			tcp_si.insert (*i);
148			}
149			else
150			i = info->second;
151
152	pcg	1.2	return i->send_packet (pkt, tos);
153	pcg	1.1	}
154
155			void tcp_connection::error ()
156			{
157			if (fd >= 0)
158			{
159			close (fd);
160			fd = -1;
161			}
162
163	pcg	1.3	delete r_pkt; r_pkt = 0;
164			delete w_pkt; w_pkt = 0;
165	pcg	1.1
166			stop ();
167			state = active ? IDLE : ERROR;
168			}
169
170	pcg	1.3	bool
171			tcp_connection::write_packet ()
172			{
173			ssize_t len;
174
175			if (w_ofs < 2)
176			{
177			u16 plen = htons (w_pkt->len);
178
179			iovec vec[2];
180			vec[0].iov_base = ((u8 *)&plen) + w_ofs;
181			vec[0].iov_len = 2 - w_ofs;
182			vec[1].iov_base = &((*w_pkt)[0]);
183			vec[1].iov_len = w_len - 2;
184
185			len = writev (fd, vec, 2);
186			}
187			else
188			len = write (fd, &((*w_pkt)[w_ofs - 2]), w_len);
189
190			if (len > 0)
191			{
192			w_ofs += len;
193			w_len -= len;
194
195			return w_len == 0;
196			}
197			else if (len < 0 && (errno == EAGAIN \|\| errno == EINTR))
198			return false;
199			else
200			{
201			error ();
202			return false;
203			}
204			}
205
206	pcg	1.1	void
207			tcp_connection::tcpv4_ev (io_watcher &w, short revents)
208			{
209			last_activity = NOW;
210
211			if (revents & (POLLERR \| POLLHUP))
212			{
213	pcg	1.3	error ();
214			return;
215	pcg	1.1	}
216
217	pcg	1.3	if (revents & POLLOUT)
218			{
219			if (state == CONNECTING)
220			{
221			state = ESTABLISHED;
222			set (POLLIN);
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	pcg	1.1	{
244			for (;;)
245			{
246			if (!r_pkt)
247			{
248			r_pkt = new vpn_packet;
249			r_ofs = 0;
250			r_len = 2; // header
251			}
252
253			ssize_t len = read (fd, &((*r_pkt)[r_ofs < 2 ? r_ofs : r_ofs - 2]), r_len);
254
255			if (len > 0)
256			{
257			r_len -= len;
258			r_ofs += len;
259
260			if (r_len == 0)
261			{
262			if (r_ofs == 2)
263			{
264			r_len = ntohs ((u16 )&((*r_pkt)[0]));
265			r_pkt->len = r_len;
266
267			if (r_len > 0 && r_len < MAXSIZE)
268			continue;
269			}
270			else
271			{
272			v.recv_vpn_packet (r_pkt, si);
273			delete r_pkt;
274			r_pkt = 0;
275
276			continue;
277			}
278			}
279	pcg	1.3	else
280			break;
281	pcg	1.1	}
282			else if (len < 0 && (errno == EINTR \|\| errno == EAGAIN))
283	pcg	1.3	break;
284	pcg	1.1
285			error ();
286	pcg	1.3	break;
287	pcg	1.1	}
288			}
289			}
290
291	pcg	1.2	bool
292	pcg	1.1	tcp_connection::send_packet (vpn_packet *pkt, int tos)
293			{
294			last_activity = NOW;
295
296			if (state == IDLE)
297			{
298			// woaw, the first lost packet ;)
299			fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
300
301			if (fd >= 0)
302			{
303			fcntl (fd, F_SETFL, O_NONBLOCK);
304
305			if (connect (fd, si.sav4 (), si.salenv4 ()) >= 0
306			\|\| errno == EINPROGRESS)
307			{
308			state = CONNECTING;
309			start (fd, POLLOUT);
310			}
311			else
312			close (fd);
313			}
314			}
315			else if (state == ESTABLISHED)
316			{
317	pcg	1.3	// drop packet if the tcp write buffer is full. this is the
318			// right thing to do, not using tcp is the right thing to do.
319			if (!w_pkt)
320			{
321			// how this maps to the underlying tcp packets we don't know
322			// and we don't care. at least we tried ;)
323			setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);
324
325			w_pkt = pkt;
326			w_ofs = 0;
327			w_len = pkt->len + 2; // length + size header
328
329			if (write_packet ())
330			w_pkt = 0;
331			else
332			{
333			w_pkt = new vpn_packet;
334			w_pkt->set (*pkt);
335	pcg	1.1
336	pcg	1.3	set (POLLIN \| POLLOUT);
337			}
338			}
339	pcg	1.1	}
340	pcg	1.2
341			return state != ERROR;
342	pcg	1.1	}
343
344			tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_)
345			: v(v_), si(si_), io_watcher(this, &tcp_connection::tcpv4_ev)
346			{
347			last_activity = NOW;
348			r_pkt = 0;
349	pcg	1.3	w_pkt = 0;
350	pcg	1.1	fd = fd_;
351
352			if (fd < 0)
353			{
354			active = true;
355			state = IDLE;
356			}
357			else
358			{
359			active = false;
360			state = ESTABLISHED;
361			start (fd, POLLIN);
362			}
363			}
364
365			tcp_connection::~tcp_connection ()
366			{
367			error ();
368			}
369
370			#endif
371