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;

  void tcpv4_ev (io_watcher &w, short revents);

  bool send_packet (vpn_packet *pkt, int tos);

  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;

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

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

  if (revents & (POLLERR | POLLHUP))
    error ();
  else if (revents & POLLOUT && state == CONNECTING)
    {
      state = ESTABLISHED;
      set (POLLIN);
    }

  else 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 if (len < 0 && (errno == EINTR || errno == EAGAIN))
            return;

          error ();
          return;
        }
    }
}

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)
    {
      // how this maps to the underlying tcp packet we don't know
      // and we don't care. at least we tried ;)
      setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);

      // we use none of the advantages of tcp; if an error occurs, just drop
      // (this happens when a tcp connection gets stuck, too, which might not be
      // the wisest thing to do.. either drop packet (too late) or make sure
      // it gets delivered)
      u16 len = htons (pkt->len);

      iovec vec[2];
      vec[0].iov_base = &len;
      vec[0].iov_len = sizeof len;
      vec[1].iov_base = &((*pkt)[0]);
      vec[1].iov_len = pkt->len;
      
      if (sizeof (u16) + pkt->len != writev (fd, vec, 2))
        error ();
    }

  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;
  fd = fd_;

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

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

#endif

Revision:	1.2
Committed:	Sun Apr 6 18:12:18 2003 UTC (21 years, 1 month ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+6 -4 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			void tcpv4_ev (io_watcher &w, short revents);
79
80	pcg	1.2	bool send_packet (vpn_packet *pkt, int tos);
81	pcg	1.1
82			void error (); // abort conenction && cleanup
83
84			operator tcp_si_map::value_type()
85			{
86			return tcp_si_map::value_type (&si, this);
87			}
88
89			tcp_connection (int fd_, const sockinfo &si_, vpn &v_);
90			~tcp_connection ();
91			};
92
93			void tcp_si_map::cleaner_cb (time_watcher &w)
94			{
95			w.at = NOW + 600;
96			tstamp to = NOW - ::conf.keepalive - 30 - 60;
97
98			for (iterator i = begin (); i != end(); )
99			if (i->second->last_activity >= to)
100			++i;
101			else
102			{
103			erase (i);
104			i = begin ();
105			}
106			}
107
108			void
109			vpn::tcpv4_ev (io_watcher &w, short revents)
110			{
111			if (revents & (POLLIN \| POLLERR))
112			{
113			struct sockaddr_in sa;
114			socklen_t sa_len = sizeof (sa);
115			int len;
116
117			int fd = accept (w.fd, (sockaddr *)&sa, &sa_len);
118
119			if (fd >= 0)
120			{
121			sockinfo si(sa, PROT_TCPv4);
122
123			slog (L_DEBUG, _("%s: accepted tcp connection"), (const char *)si);//D
124
125			fcntl (fd, F_SETFL, O_NONBLOCK);
126
127			tcp_connection i = new tcp_connection (fd, si, this);
128			tcp_si.insert (*i);
129			}
130			}
131			}
132
133	pcg	1.2	bool
134	pcg	1.1	vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
135			{
136			tcp_si_map::iterator info = tcp_si.find (&si);
137
138			tcp_connection *i;
139
140			if (info == tcp_si.end ())
141			{
142			i = new tcp_connection (-1, si, *this);
143			tcp_si.insert (*i);
144			}
145			else
146			i = info->second;
147
148	pcg	1.2	return i->send_packet (pkt, tos);
149	pcg	1.1	}
150
151			void tcp_connection::error ()
152			{
153			if (fd >= 0)
154			{
155			close (fd);
156			fd = -1;
157			}
158
159			delete r_pkt;
160			r_pkt = 0;
161
162			stop ();
163			state = active ? IDLE : ERROR;
164			}
165
166			void
167			tcp_connection::tcpv4_ev (io_watcher &w, short revents)
168			{
169			last_activity = NOW;
170
171			if (revents & (POLLERR \| POLLHUP))
172			error ();
173			else if (revents & POLLOUT && state == CONNECTING)
174			{
175			state = ESTABLISHED;
176			set (POLLIN);
177			}
178
179			else if (revents & POLLIN)
180			{
181			for (;;)
182			{
183			if (!r_pkt)
184			{
185			r_pkt = new vpn_packet;
186			r_ofs = 0;
187			r_len = 2; // header
188			}
189
190			ssize_t len = read (fd, &((*r_pkt)[r_ofs < 2 ? r_ofs : r_ofs - 2]), r_len);
191
192			if (len > 0)
193			{
194			r_len -= len;
195			r_ofs += len;
196
197			if (r_len == 0)
198			{
199			if (r_ofs == 2)
200			{
201			r_len = ntohs ((u16 )&((*r_pkt)[0]));
202			r_pkt->len = r_len;
203
204			if (r_len > 0 && r_len < MAXSIZE)
205			continue;
206			}
207			else
208			{
209			v.recv_vpn_packet (r_pkt, si);
210			delete r_pkt;
211			r_pkt = 0;
212
213			continue;
214			}
215			}
216
217			}
218			else if (len < 0 && (errno == EINTR \|\| errno == EAGAIN))
219			return;
220
221			error ();
222			return;
223			}
224			}
225			}
226
227	pcg	1.2	bool
228	pcg	1.1	tcp_connection::send_packet (vpn_packet *pkt, int tos)
229			{
230			last_activity = NOW;
231
232			if (state == IDLE)
233			{
234			// woaw, the first lost packet ;)
235			fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
236
237			if (fd >= 0)
238			{
239			fcntl (fd, F_SETFL, O_NONBLOCK);
240
241			if (connect (fd, si.sav4 (), si.salenv4 ()) >= 0
242			\|\| errno == EINPROGRESS)
243			{
244			state = CONNECTING;
245			start (fd, POLLOUT);
246			}
247			else
248			close (fd);
249			}
250			}
251			else if (state == ESTABLISHED)
252			{
253			// how this maps to the underlying tcp packet we don't know
254			// and we don't care. at least we tried ;)
255			setsockopt (fd, SOL_IP, IP_TOS, &tos, sizeof tos);
256
257			// we use none of the advantages of tcp; if an error occurs, just drop
258			// (this happens when a tcp connection gets stuck, too, which might not be
259			// the wisest thing to do.. either drop packet (too late) or make sure
260			// it gets delivered)
261			u16 len = htons (pkt->len);
262
263			iovec vec[2];
264			vec[0].iov_base = &len;
265			vec[0].iov_len = sizeof len;
266			vec[1].iov_base = &((*pkt)[0]);
267			vec[1].iov_len = pkt->len;
268
269			if (sizeof (u16) + pkt->len != writev (fd, vec, 2))
270			error ();
271			}
272	pcg	1.2
273			return state != ERROR;
274	pcg	1.1	}
275
276			tcp_connection::tcp_connection (int fd_, const sockinfo &si_, vpn &v_)
277			: v(v_), si(si_), io_watcher(this, &tcp_connection::tcpv4_ev)
278			{
279			last_activity = NOW;
280			r_pkt = 0;
281			fd = fd_;
282
283			if (fd < 0)
284			{
285			active = true;
286			state = IDLE;
287			}
288			else
289			{
290			active = false;
291			state = ESTABLISHED;
292			start (fd, POLLIN);
293			}
294			}
295
296			tcp_connection::~tcp_connection ()
297			{
298			error ();
299			}
300
301			#endif
302