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:	1.9
Committed:	Tue Feb 8 23:13:48 2011 UTC (13 years, 3 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_0, rel-2_25, HEAD
Changes since 1.8:	+2 -2 lines
Log Message:	whitespace cleanup
#	Content
1	/*
2	ether_emu.C -- ethernet "emulator" library
3	Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
4
5	This file is part of GVPE.
6
7	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	*/
31
32	#include "config.h"
33
34	#include <map>
35
36	#include "vpn.h"
37
38	extern struct vpn network;
39
40	struct ether_emu : map<u32, int>
41	{
42	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