gvpe/src/ether_emu.C

/*
    ether_emu.C -- ethernet "emulator" library
    Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
 
    This file is part of GVPE.

    GVPE 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 3 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, see <http://www.gnu.org/licenses/>.
   
    Additional permission under GNU GPL version 3 section 7
   
    If you modify this Program, or any covered work, by linking or
    combining it with the OpenSSL project's OpenSSL library (or a modified
    version of that library), containing parts covered by the terms of the
    OpenSSL or SSLeay licenses, the licensors of this Program grant you
    additional permission to convey the resulting work.  Corresponding
    Source for a non-source form of such a combination shall include the
    source code for the parts of OpenSSL used as well as that of the
    covered work.
*/

#include "config.h"

#include <map>

#include "vpn.h"

extern struct vpn network;

struct ether_emu : map<u32, int>
{
  typedef map<u32, int> ipv4map;
  ipv4map ipv4;

  bool tun_to_tap (tap_packet *pkt);
  bool tap_to_tun (tap_packet *pkt);

  void set_ipv4 (u32 ip, int dst)
    {
      (ipv4.insert (pair<u32, int>(ip, dst)).first)->second = dst;
    }
};

static struct ether_emu ether_emu;

bool 
ether_emu::tun_to_tap (tap_packet *pkt)
{
  int dst;

  if (pkt->is_ipv4 ())
    {
      // update arp cache for _local_ hosts
      set_ipv4 (pkt->ipv4_src (), THISNODE->id);

      ipv4map::iterator i = ipv4.find (pkt->ipv4_dst ());

      if (i == ipv4.end ())
        {
          u32 ip_src = pkt->ipv4_src ();
          u32 ip_dst = pkt->ipv4_dst ();

          // throw away current packet and make it an arp request
          (*pkt)[12] = 0x08; (*pkt)[13] = 0x06;
          (*pkt)[14] = 0x00; (*pkt)[15] = 0x01; // hw
          (*pkt)[16] = 0x08; (*pkt)[17] = 0x00; // prot
          (*pkt)[18] = 0x06; // hw_len
          (*pkt)[19] = 0x04; // prot_len
          (*pkt)[20] = 0x00; (*pkt)[21] = 0x01; // op

          id2mac (THISNODE->id, &(*pkt)[22]);
          *(u32 *)&(*pkt)[28] = ip_src;
          id2mac (0, &(*pkt)[32]);
          *(u32 *)&(*pkt)[38] = ip_dst;

          pkt->len = 42;

          dst = 0;
        }
      else
        dst = i->second;
    }
  else
    dst = 0; // broadcast non-ip

  id2mac (THISNODE->id, pkt->src);
  id2mac (dst, pkt->dst);

  return true;
}

bool 
ether_emu::tap_to_tun (tap_packet *pkt)
{
  if (pkt->is_arp ())
    {
      u32 ip_src = *(u32 *)&(*pkt)[28];

      // always update with all info we can get. in this case, the arp sender.
      set_ipv4 (ip_src, mac2id (&(*pkt)[22]));

      //TODO: remove cache dumper
      //for (ipv4map::iterator i = ipv4.begin (); i != ipv4.end (); ++i) printf ("%08lx => %d\n", i->first, i->second);

      if ((*pkt)[20] == 0x00 && (*pkt)[21] == 0x01) // arp request
        {
          // send a reply, if applicable
          u32 ip_dst = *(u32 *)&(*pkt)[38];
          ipv4map::iterator i = ipv4.find (ip_dst);
          
          // TODO: look up list of local networks and answer for them
          if (i != ipv4.end () && i->second == THISNODE->id)
            {
              // create an arp reply
              tap_packet *rep = new tap_packet;

              id2mac (THISNODE->id, rep->src);
              memcpy (rep->dst, pkt->src, sizeof (mac));

              (*rep)[12] = 0x08; (*rep)[13] = 0x06;
              (*rep)[14] = 0x00; (*rep)[15] = 0x01; // hw
              (*rep)[16] = 0x08; (*rep)[17] = 0x00; // prot
              (*rep)[18] = 0x06; // hw_len
              (*rep)[19] = 0x04; // prot_len
              (*rep)[20] = 0x00; (*rep)[21] = 0x02; // op

              id2mac (THISNODE->id, &(*rep)[22]);
              *(u32 *)&(*rep)[28] = ip_dst;
              memcpy (&(*rep)[32], &(*pkt)[22], sizeof (mac));
              *(u32 *)&(*rep)[38] = ip_src;

              rep->len = 42;

              network.inject_data_packet (rep, mac2id (rep->dst));

              delete rep;
            }
        }
      else if ((*pkt)[20] == 0x00 && (*pkt)[21] == 0x02) // arp reply
        set_ipv4 (*(u32 *)&(*pkt)[28], mac2id (&(*pkt)[22]));

      return false;
    }
  else if (pkt->is_ipv4 ())
    {
      // update arp cache
      set_ipv4 (pkt->ipv4_src (), mac2id (pkt->src));
      set_ipv4 (pkt->ipv4_dst (), mac2id (pkt->dst));
    }

  return true;
}

Revision:	1.8
Committed:	Thu Aug 7 17:54:27 2008 UTC (15 years, 9 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-2_2, rel-2_21, rel-2_22
Changes since 1.7:	+24 -14 lines
Log Message:	update to gplv3, finally
#	User	Rev	Content
1	pcg	1.1	/*
2			ether_emu.C -- ethernet "emulator" library
3	pcg	1.8	Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
4	pcg	1.1
5	pcg	1.5	This file is part of GVPE.
6
7	pcg	1.8	GVPE is free software; you can redistribute it and/or modify it
8			under the terms of the GNU General Public License as published by the
9			Free Software Foundation; either version 3 of the License, or (at your
10			option) any later version.
11
12			This program is distributed in the hope that it will be useful, but
13			WITHOUT ANY WARRANTY; without even the implied warranty of
14			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15			Public License for more details.
16
17			You should have received a copy of the GNU General Public License along
18			with this program; if not, see <http://www.gnu.org/licenses/>.
19
20			Additional permission under GNU GPL version 3 section 7
21
22			If you modify this Program, or any covered work, by linking or
23			combining it with the OpenSSL project's OpenSSL library (or a modified
24			version of that library), containing parts covered by the terms of the
25			OpenSSL or SSLeay licenses, the licensors of this Program grant you
26			additional permission to convey the resulting work. Corresponding
27			Source for a non-source form of such a combination shall include the
28			source code for the parts of OpenSSL used as well as that of the
29			covered work.
30	pcg	1.1	*/
31
32			#include "config.h"
33
34			#include <map>
35
36			#include "vpn.h"
37
38	pcg	1.3	extern struct vpn network;
39
40	pcg	1.7	struct ether_emu : map<u32, int>
41			{
42	pcg	1.1	typedef map<u32, int> ipv4map;
43			ipv4map ipv4;
44
45			bool tun_to_tap (tap_packet *pkt);
46			bool tap_to_tun (tap_packet *pkt);
47
48			void set_ipv4 (u32 ip, int dst)
49			{
50			(ipv4.insert (pair<u32, int>(ip, dst)).first)->second = dst;
51			}
52			};
53
54			static struct ether_emu ether_emu;
55
56			bool
57			ether_emu::tun_to_tap (tap_packet *pkt)
58			{
59			int dst;
60
61			if (pkt->is_ipv4 ())
62			{
63			// update arp cache for _local_ hosts
64			set_ipv4 (pkt->ipv4_src (), THISNODE->id);
65
66			ipv4map::iterator i = ipv4.find (pkt->ipv4_dst ());
67
68			if (i == ipv4.end ())
69			{
70			u32 ip_src = pkt->ipv4_src ();
71			u32 ip_dst = pkt->ipv4_dst ();
72
73			// throw away current packet and make it an arp request
74			(pkt)[12] = 0x08; (pkt)[13] = 0x06;
75			(pkt)[14] = 0x00; (pkt)[15] = 0x01; // hw
76			(pkt)[16] = 0x08; (pkt)[17] = 0x00; // prot
77			(*pkt)[18] = 0x06; // hw_len
78			(*pkt)[19] = 0x04; // prot_len
79			(pkt)[20] = 0x00; (pkt)[21] = 0x01; // op
80
81			id2mac (THISNODE->id, &(*pkt)[22]);
82			(u32 )&(*pkt)[28] = ip_src;
83			id2mac (0, &(*pkt)[32]);
84			(u32 )&(*pkt)[38] = ip_dst;
85
86			pkt->len = 42;
87
88			dst = 0;
89			}
90			else
91			dst = i->second;
92			}
93			else
94			dst = 0; // broadcast non-ip
95
96			id2mac (THISNODE->id, pkt->src);
97			id2mac (dst, pkt->dst);
98
99			return true;
100			}
101
102			bool
103			ether_emu::tap_to_tun (tap_packet *pkt)
104			{
105			if (pkt->is_arp ())
106			{
107			u32 ip_src = (u32 )&(*pkt)[28];
108
109			// always update with all info we can get. in this case, the arp sender.
110			set_ipv4 (ip_src, mac2id (&(*pkt)[22]));
111
112			//TODO: remove cache dumper
113			//for (ipv4map::iterator i = ipv4.begin (); i != ipv4.end (); ++i) printf ("%08lx => %d\n", i->first, i->second);
114
115			if ((pkt)[20] == 0x00 && (pkt)[21] == 0x01) // arp request
116			{
117			// send a reply, if applicable
118			u32 ip_dst = (u32 )&(*pkt)[38];
119			ipv4map::iterator i = ipv4.find (ip_dst);
120
121			// TODO: look up list of local networks and answer for them
122			if (i != ipv4.end () && i->second == THISNODE->id)
123			{
124			// create an arp reply
125			tap_packet *rep = new tap_packet;
126
127			id2mac (THISNODE->id, rep->src);
128			memcpy (rep->dst, pkt->src, sizeof (mac));
129
130			(rep)[12] = 0x08; (rep)[13] = 0x06;
131			(rep)[14] = 0x00; (rep)[15] = 0x01; // hw
132			(rep)[16] = 0x08; (rep)[17] = 0x00; // prot
133			(*rep)[18] = 0x06; // hw_len
134			(*rep)[19] = 0x04; // prot_len
135			(rep)[20] = 0x00; (rep)[21] = 0x02; // op
136
137			id2mac (THISNODE->id, &(*rep)[22]);
138			(u32 )&(*rep)[28] = ip_dst;
139			memcpy (&(rep)[32], &(pkt)[22], sizeof (mac));
140			(u32 )&(*rep)[38] = ip_src;
141
142			rep->len = 42;
143
144			network.inject_data_packet (rep, mac2id (rep->dst));
145
146			delete rep;
147			}
148			}
149			else if ((pkt)[20] == 0x00 && (pkt)[21] == 0x02) // arp reply
150			set_ipv4 ((u32 )&(pkt)[28], mac2id (&(pkt)[22]));
151
152			return false;
153			}
154			else if (pkt->is_ipv4 ())
155			{
156			// update arp cache
157			set_ipv4 (pkt->ipv4_src (), mac2id (pkt->src));
158			set_ipv4 (pkt->ipv4_dst (), mac2id (pkt->dst));
159			}
160
161			return true;
162			}
163