| 1 | /* |
1 | /* |
| 2 | vpn.C -- handle the protocol, encryption, handshaking etc. |
2 | vpn.C -- handle the protocol, encryption, handshaking etc. |
| 3 | Copyright (C) 2003-2008,2010,2011 Marc Lehmann <gvpe@schmorp.de> |
3 | Copyright (C) 2003-2008,2010,2011,2013 Marc Lehmann <gvpe@schmorp.de> |
| 4 | |
4 | |
| 5 | This file is part of GVPE. |
5 | This file is part of GVPE. |
| 6 | |
6 | |
| 7 | GVPE is free software; you can redistribute it and/or modify it |
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 |
8 | under the terms of the GNU General Public License as published by the |
| … | |
… | |
| 78 | { |
78 | { |
| 79 | // the tunnel device mtu should be the physical mtu - overhead |
79 | // the tunnel device mtu should be the physical mtu - overhead |
| 80 | // the tricky part is rounding to the cipher key blocksize |
80 | // the tricky part is rounding to the cipher key blocksize |
| 81 | int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD; |
81 | int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD; |
| 82 | mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion |
82 | mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion |
| 83 | mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round |
83 | mtu -= mtu % BLOCK_SIZE (CIPHER); // round |
| 84 | mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again |
84 | mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again |
| 85 | |
85 | |
| 86 | char *env; |
86 | char *env; |
| 87 | asprintf (&env, "CONFBASE=%s", confbase); putenv (env); |
87 | asprintf (&env, "CONFBASE=%s", confbase); putenv (env); |
| 88 | asprintf (&env, "IFNAME=%s", tap->interface ()); putenv (env); |
88 | asprintf (&env, "IFNAME=%s", tap->interface ()); putenv (env); |
