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/* |
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connection.C -- manage a single connection |
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Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> |
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|
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This file is part of GVPE. |
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|
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GVPE is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with gvpe; if not, write to the Free Software |
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Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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#include "config.h" |
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|
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#include <cassert> |
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|
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#include <list> |
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|
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#include <openssl/rand.h> |
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#include <openssl/evp.h> |
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#include <openssl/rsa.h> |
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#include <openssl/err.h> |
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|
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#include "gettext.h" |
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|
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#include "conf.h" |
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#include "slog.h" |
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#include "device.h" |
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#include "vpn.h" |
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#include "connection.h" |
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|
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#include "netcompat.h" |
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|
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#if !HAVE_RAND_PSEUDO_BYTES |
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# define RAND_pseudo_bytes RAND_bytes |
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#endif |
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|
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#define MAGIC "vped\xbd\xc6\xdb\x82" // 8 bytes of magic |
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|
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#define ULTRA_FAST 1 |
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#define HLOG 15 |
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#include "lzf/lzf.h" |
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#include "lzf/lzf_c.c" |
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#include "lzf/lzf_d.c" |
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|
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struct crypto_ctx |
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{ |
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EVP_CIPHER_CTX cctx; |
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HMAC_CTX hctx; |
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|
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crypto_ctx (const rsachallenge &challenge, int enc); |
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~crypto_ctx (); |
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}; |
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|
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crypto_ctx::crypto_ctx (const rsachallenge &challenge, int enc) |
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{ |
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EVP_CIPHER_CTX_init (&cctx); |
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require (EVP_CipherInit_ex (&cctx, CIPHER, 0, &challenge[CHG_CIPHER_KEY], 0, enc)); |
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HMAC_CTX_init (&hctx); |
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HMAC_Init_ex (&hctx, &challenge[CHG_HMAC_KEY], HMAC_KEYLEN, DIGEST, 0); |
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} |
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|
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crypto_ctx::~crypto_ctx () |
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{ |
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require (EVP_CIPHER_CTX_cleanup (&cctx)); |
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HMAC_CTX_cleanup (&hctx); |
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} |
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|
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static void |
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rsa_hash (const rsaid &id, const rsachallenge &chg, rsaresponse &h) |
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{ |
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EVP_MD_CTX ctx; |
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|
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EVP_MD_CTX_init (&ctx); |
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require (EVP_DigestInit (&ctx, RSA_HASH)); |
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require (EVP_DigestUpdate(&ctx, &chg, sizeof chg)); |
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require (EVP_DigestUpdate(&ctx, &id, sizeof id)); |
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require (EVP_DigestFinal (&ctx, (unsigned char *)&h, 0)); |
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EVP_MD_CTX_cleanup (&ctx); |
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} |
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|
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struct rsa_entry { |
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tstamp expire; |
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rsaid id; |
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rsachallenge chg; |
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}; |
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|
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struct rsa_cache : list<rsa_entry> |
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{ |
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void cleaner_cb (time_watcher &w); time_watcher cleaner; |
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|
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bool find (const rsaid &id, rsachallenge &chg) |
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{ |
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for (iterator i = begin (); i != end (); ++i) |
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{ |
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if (!memcmp (&id, &i->id, sizeof id) && i->expire > NOW) |
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{ |
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memcpy (&chg, &i->chg, sizeof chg); |
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|
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erase (i); |
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return true; |
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} |
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} |
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|
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if (cleaner.at < NOW) |
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cleaner.start (NOW + RSA_TTL); |
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|
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return false; |
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} |
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|
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void gen (rsaid &id, rsachallenge &chg) |
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{ |
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rsa_entry e; |
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|
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RAND_bytes ((unsigned char *)&id, sizeof id); |
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RAND_bytes ((unsigned char *)&chg, sizeof chg); |
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|
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e.expire = NOW + RSA_TTL; |
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e.id = id; |
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memcpy (&e.chg, &chg, sizeof chg); |
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|
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push_back (e); |
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|
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if (cleaner.at < NOW) |
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cleaner.start (NOW + RSA_TTL); |
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} |
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|
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rsa_cache () |
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: cleaner (this, &rsa_cache::cleaner_cb) |
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{ } |
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|
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} rsa_cache; |
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|
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void rsa_cache::cleaner_cb (time_watcher &w) |
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{ |
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if (!empty ()) |
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{ |
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w.start (NOW + RSA_TTL); |
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|
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for (iterator i = begin (); i != end (); ) |
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if (i->expire <= NOW) |
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i = erase (i); |
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else |
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++i; |
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} |
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} |
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|
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////////////////////////////////////////////////////////////////////////////// |
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|
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void pkt_queue::put (net_packet *p) |
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{ |
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if (queue[i]) |
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{ |
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delete queue[i]; |
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j = (j + 1) % QUEUEDEPTH; |
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} |
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|
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queue[i] = p; |
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|
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i = (i + 1) % QUEUEDEPTH; |
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} |
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|
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net_packet *pkt_queue::get () |
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{ |
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net_packet *p = queue[j]; |
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|
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if (p) |
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{ |
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queue[j] = 0; |
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j = (j + 1) % QUEUEDEPTH; |
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} |
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|
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return p; |
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} |
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|
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pkt_queue::pkt_queue () |
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{ |
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memset (queue, 0, sizeof (queue)); |
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i = 0; |
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j = 0; |
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} |
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|
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pkt_queue::~pkt_queue () |
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{ |
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for (i = QUEUEDEPTH; --i > 0; ) |
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delete queue[i]; |
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} |
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|
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struct net_rateinfo { |
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u32 host; |
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double pcnt, diff; |
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tstamp last; |
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}; |
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|
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// only do action once every x seconds per host whole allowing bursts. |
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// this implementation ("splay list" ;) is inefficient, |
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// but low on resources. |
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struct net_rate_limiter : list<net_rateinfo> |
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{ |
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# define NRL_ALPHA (1. - 1. / 600.) // allow bursts |
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# define NRL_CUTOFF 10. // one event every CUTOFF seconds |
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# define NRL_EXPIRE (NRL_CUTOFF * 30.) // expire entries after this time |
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# define NRL_MAXDIF (NRL_CUTOFF * (1. / (1. - NRL_ALPHA))) // maximum diff /count value |
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|
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bool can (const sockinfo &si) { return can((u32)si.host); } |
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bool can (u32 host); |
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}; |
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|
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net_rate_limiter auth_rate_limiter, reset_rate_limiter; |
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|
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bool net_rate_limiter::can (u32 host) |
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{ |
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iterator i; |
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|
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for (i = begin (); i != end (); ) |
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if (i->host == host) |
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break; |
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else if (i->last < NOW - NRL_EXPIRE) |
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i = erase (i); |
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else |
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i++; |
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|
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if (i == end ()) |
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{ |
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net_rateinfo ri; |
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|
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ri.host = host; |
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ri.pcnt = 1.; |
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ri.diff = NRL_MAXDIF; |
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ri.last = NOW; |
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|
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push_front (ri); |
242 |
|
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return true; |
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} |
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else |
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{ |
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net_rateinfo ri (*i); |
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erase (i); |
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|
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ri.pcnt = ri.pcnt * NRL_ALPHA; |
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ri.diff = ri.diff * NRL_ALPHA + (NOW - ri.last); |
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|
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ri.last = NOW; |
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|
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double dif = ri.diff / ri.pcnt; |
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|
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bool send = dif > NRL_CUTOFF; |
258 |
|
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if (dif > NRL_MAXDIF) |
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{ |
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ri.pcnt = 1.; |
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ri.diff = NRL_MAXDIF; |
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} |
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else if (send) |
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ri.pcnt++; |
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|
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push_front (ri); |
268 |
|
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return send; |
270 |
} |
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} |
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|
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///////////////////////////////////////////////////////////////////////////// |
274 |
|
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unsigned char hmac_packet::hmac_digest[EVP_MAX_MD_SIZE]; |
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|
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void hmac_packet::hmac_gen (crypto_ctx *ctx) |
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{ |
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unsigned int xlen; |
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|
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HMAC_CTX *hctx = &ctx->hctx; |
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|
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HMAC_Init_ex (hctx, 0, 0, 0, 0); |
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HMAC_Update (hctx, ((unsigned char *) this) + sizeof (hmac_packet), |
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len - sizeof (hmac_packet)); |
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HMAC_Final (hctx, (unsigned char *) &hmac_digest, &xlen); |
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} |
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|
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void |
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hmac_packet::hmac_set (crypto_ctx *ctx) |
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{ |
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hmac_gen (ctx); |
293 |
|
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memcpy (hmac, hmac_digest, HMACLENGTH); |
295 |
} |
296 |
|
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bool |
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hmac_packet::hmac_chk (crypto_ctx *ctx) |
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{ |
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hmac_gen (ctx); |
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|
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return !memcmp (hmac, hmac_digest, HMACLENGTH); |
303 |
} |
304 |
|
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void vpn_packet::set_hdr (ptype type_, unsigned int dst) |
306 |
{ |
307 |
type = type_; |
308 |
|
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int src = THISNODE->id; |
310 |
|
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src1 = src; |
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srcdst = ((src >> 8) << 4) | (dst >> 8); |
313 |
dst1 = dst; |
314 |
} |
315 |
|
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#define MAXVPNDATA (MAX_MTU - 6 - 6) |
317 |
#define DATAHDR (sizeof (u32) + RAND_SIZE) |
318 |
|
319 |
struct vpndata_packet : vpn_packet |
320 |
{ |
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u8 data[MAXVPNDATA + DATAHDR]; // seqno |
322 |
|
323 |
void setup (connection *conn, int dst, u8 *d, u32 len, u32 seqno); |
324 |
tap_packet *unpack (connection *conn, u32 &seqno); |
325 |
private: |
326 |
|
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const u32 data_hdr_size () const |
328 |
{ |
329 |
return sizeof (vpndata_packet) - sizeof (net_packet) - MAXVPNDATA - DATAHDR; |
330 |
} |
331 |
}; |
332 |
|
333 |
void |
334 |
vpndata_packet::setup (connection *conn, int dst, u8 *d, u32 l, u32 seqno) |
335 |
{ |
336 |
EVP_CIPHER_CTX *cctx = &conn->octx->cctx; |
337 |
int outl = 0, outl2; |
338 |
ptype type = PT_DATA_UNCOMPRESSED; |
339 |
|
340 |
#if ENABLE_COMPRESSION |
341 |
u8 cdata[MAX_MTU]; |
342 |
|
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if (conn->features & ENABLE_COMPRESSION) |
344 |
{ |
345 |
u32 cl = lzf_compress (d, l, cdata + 2, (l - 2) & ~7); |
346 |
|
347 |
if (cl) |
348 |
{ |
349 |
type = PT_DATA_COMPRESSED; |
350 |
d = cdata; |
351 |
l = cl + 2; |
352 |
|
353 |
d[0] = cl >> 8; |
354 |
d[1] = cl; |
355 |
} |
356 |
} |
357 |
#endif |
358 |
|
359 |
require (EVP_EncryptInit_ex (cctx, 0, 0, 0, 0)); |
360 |
|
361 |
struct { |
362 |
#if RAND_SIZE |
363 |
u8 rnd[RAND_SIZE]; |
364 |
#endif |
365 |
u32 seqno; |
366 |
} datahdr; |
367 |
|
368 |
datahdr.seqno = ntohl (seqno); |
369 |
#if RAND_SIZE |
370 |
RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE); |
371 |
#endif |
372 |
|
373 |
require (EVP_EncryptUpdate (cctx, |
374 |
(unsigned char *) data + outl, &outl2, |
375 |
(unsigned char *) &datahdr, DATAHDR)); |
376 |
outl += outl2; |
377 |
|
378 |
require (EVP_EncryptUpdate (cctx, |
379 |
(unsigned char *) data + outl, &outl2, |
380 |
(unsigned char *) d, l)); |
381 |
outl += outl2; |
382 |
|
383 |
require (EVP_EncryptFinal_ex (cctx, (unsigned char *) data + outl, &outl2)); |
384 |
outl += outl2; |
385 |
|
386 |
len = outl + data_hdr_size (); |
387 |
|
388 |
set_hdr (type, dst); |
389 |
|
390 |
hmac_set (conn->octx); |
391 |
} |
392 |
|
393 |
tap_packet * |
394 |
vpndata_packet::unpack (connection *conn, u32 &seqno) |
395 |
{ |
396 |
EVP_CIPHER_CTX *cctx = &conn->ictx->cctx; |
397 |
int outl = 0, outl2; |
398 |
tap_packet *p = new tap_packet; |
399 |
u8 *d; |
400 |
u32 l = len - data_hdr_size (); |
401 |
|
402 |
require (EVP_DecryptInit_ex (cctx, 0, 0, 0, 0)); |
403 |
|
404 |
#if ENABLE_COMPRESSION |
405 |
u8 cdata[MAX_MTU]; |
406 |
|
407 |
if (type == PT_DATA_COMPRESSED) |
408 |
d = cdata; |
409 |
else |
410 |
#endif |
411 |
d = &(*p)[6 + 6 - DATAHDR]; |
412 |
|
413 |
/* this overwrites part of the src mac, but we fix that later */ |
414 |
require (EVP_DecryptUpdate (cctx, |
415 |
d, &outl2, |
416 |
(unsigned char *)&data, len - data_hdr_size ())); |
417 |
outl += outl2; |
418 |
|
419 |
require (EVP_DecryptFinal_ex (cctx, (unsigned char *)d + outl, &outl2)); |
420 |
outl += outl2; |
421 |
|
422 |
seqno = ntohl (*(u32 *)(d + RAND_SIZE)); |
423 |
|
424 |
id2mac (dst () ? dst() : THISNODE->id, p->dst); |
425 |
id2mac (src (), p->src); |
426 |
|
427 |
#if ENABLE_COMPRESSION |
428 |
if (type == PT_DATA_COMPRESSED) |
429 |
{ |
430 |
u32 cl = (d[DATAHDR] << 8) | d[DATAHDR + 1]; |
431 |
|
432 |
p->len = lzf_decompress (d + DATAHDR + 2, cl < MAX_MTU ? cl : 0, |
433 |
&(*p)[6 + 6], MAX_MTU) |
434 |
+ 6 + 6; |
435 |
} |
436 |
else |
437 |
p->len = outl + (6 + 6 - DATAHDR); |
438 |
#endif |
439 |
|
440 |
return p; |
441 |
} |
442 |
|
443 |
struct ping_packet : vpn_packet |
444 |
{ |
445 |
void setup (int dst, ptype type) |
446 |
{ |
447 |
set_hdr (type, dst); |
448 |
len = sizeof (*this) - sizeof (net_packet); |
449 |
} |
450 |
}; |
451 |
|
452 |
struct config_packet : vpn_packet |
453 |
{ |
454 |
// actually, hmaclen cannot be checked because the hmac |
455 |
// field comes before this data, so peers with other |
456 |
// hmacs simply will not work. |
457 |
u8 prot_major, prot_minor, randsize, hmaclen; |
458 |
u8 flags, challengelen, features, pad3; |
459 |
u32 cipher_nid, digest_nid, hmac_nid; |
460 |
|
461 |
void setup (ptype type, int dst); |
462 |
bool chk_config () const; |
463 |
|
464 |
static u8 get_features () |
465 |
{ |
466 |
u8 f = 0; |
467 |
#if ENABLE_COMPRESSION |
468 |
f |= FEATURE_COMPRESSION; |
469 |
#endif |
470 |
#if ENABLE_ROHC |
471 |
f |= FEATURE_ROHC; |
472 |
#endif |
473 |
return f; |
474 |
} |
475 |
}; |
476 |
|
477 |
void config_packet::setup (ptype type, int dst) |
478 |
{ |
479 |
prot_major = PROTOCOL_MAJOR; |
480 |
prot_minor = PROTOCOL_MINOR; |
481 |
randsize = RAND_SIZE; |
482 |
hmaclen = HMACLENGTH; |
483 |
flags = 0; |
484 |
challengelen = sizeof (rsachallenge); |
485 |
features = get_features (); |
486 |
|
487 |
cipher_nid = htonl (EVP_CIPHER_nid (CIPHER)); |
488 |
digest_nid = htonl (EVP_MD_type (RSA_HASH)); |
489 |
hmac_nid = htonl (EVP_MD_type (DIGEST)); |
490 |
|
491 |
len = sizeof (*this) - sizeof (net_packet); |
492 |
set_hdr (type, dst); |
493 |
} |
494 |
|
495 |
bool config_packet::chk_config () const |
496 |
{ |
497 |
if (prot_major != PROTOCOL_MAJOR) |
498 |
slog (L_WARN, _("major version mismatch (remote %d <=> local %d)"), prot_major, PROTOCOL_MAJOR); |
499 |
else if (randsize != RAND_SIZE) |
500 |
slog (L_WARN, _("rand size mismatch (remote %d <=> local %d)"), randsize, RAND_SIZE); |
501 |
else if (hmaclen != HMACLENGTH) |
502 |
slog (L_WARN, _("hmac length mismatch (remote %d <=> local %d)"), hmaclen, HMACLENGTH); |
503 |
else if (challengelen != sizeof (rsachallenge)) |
504 |
slog (L_WARN, _("challenge length mismatch (remote %d <=> local %d)"), challengelen, sizeof (rsachallenge)); |
505 |
else if (cipher_nid != htonl (EVP_CIPHER_nid (CIPHER))) |
506 |
slog (L_WARN, _("cipher mismatch (remote %x <=> local %x)"), ntohl (cipher_nid), EVP_CIPHER_nid (CIPHER)); |
507 |
else if (digest_nid != htonl (EVP_MD_type (RSA_HASH))) |
508 |
slog (L_WARN, _("digest mismatch (remote %x <=> local %x)"), ntohl (digest_nid), EVP_MD_type (RSA_HASH)); |
509 |
else if (hmac_nid != htonl (EVP_MD_type (DIGEST))) |
510 |
slog (L_WARN, _("hmac mismatch (remote %x <=> local %x)"), ntohl (hmac_nid), EVP_MD_type (DIGEST)); |
511 |
else |
512 |
return true; |
513 |
|
514 |
return false; |
515 |
} |
516 |
|
517 |
struct auth_req_packet : config_packet |
518 |
{ |
519 |
char magic[8]; |
520 |
u8 initiate; // false if this is just an automatic reply |
521 |
u8 protocols; // supported protocols (will be patched on forward) |
522 |
u8 pad2, pad3; |
523 |
rsaid id; |
524 |
rsaencrdata encr; |
525 |
|
526 |
auth_req_packet (int dst, bool initiate_, u8 protocols_) |
527 |
{ |
528 |
config_packet::setup (PT_AUTH_REQ, dst); |
529 |
strncpy (magic, MAGIC, 8); |
530 |
initiate = !!initiate_; |
531 |
protocols = protocols_; |
532 |
|
533 |
len = sizeof (*this) - sizeof (net_packet); |
534 |
} |
535 |
}; |
536 |
|
537 |
struct auth_res_packet : config_packet |
538 |
{ |
539 |
rsaid id; |
540 |
u8 pad1, pad2, pad3; |
541 |
u8 response_len; // encrypted length |
542 |
rsaresponse response; |
543 |
|
544 |
auth_res_packet (int dst) |
545 |
{ |
546 |
config_packet::setup (PT_AUTH_RES, dst); |
547 |
|
548 |
len = sizeof (*this) - sizeof (net_packet); |
549 |
} |
550 |
}; |
551 |
|
552 |
struct connect_req_packet : vpn_packet |
553 |
{ |
554 |
u8 id, protocols; |
555 |
u8 pad1, pad2; |
556 |
|
557 |
connect_req_packet (int dst, int id_, u8 protocols_) |
558 |
: id(id_) |
559 |
, protocols(protocols_) |
560 |
{ |
561 |
set_hdr (PT_CONNECT_REQ, dst); |
562 |
len = sizeof (*this) - sizeof (net_packet); |
563 |
} |
564 |
}; |
565 |
|
566 |
struct connect_info_packet : vpn_packet |
567 |
{ |
568 |
u8 id, protocols; |
569 |
u8 pad1, pad2; |
570 |
sockinfo si; |
571 |
|
572 |
connect_info_packet (int dst, int id_, const sockinfo &si_, u8 protocols_) |
573 |
: id(id_) |
574 |
, protocols(protocols_) |
575 |
, si(si_) |
576 |
{ |
577 |
set_hdr (PT_CONNECT_INFO, dst); |
578 |
|
579 |
len = sizeof (*this) - sizeof (net_packet); |
580 |
} |
581 |
}; |
582 |
|
583 |
///////////////////////////////////////////////////////////////////////////// |
584 |
|
585 |
void |
586 |
connection::connection_established () |
587 |
{ |
588 |
if (ictx && octx) |
589 |
{ |
590 |
connectmode = conf->connectmode; |
591 |
|
592 |
// make sure rekeying timeouts are slightly asymmetric |
593 |
rekey.start (NOW + ::conf.rekey |
594 |
+ (conf->id > THISNODE->id ? 10 : 0)); |
595 |
keepalive.start (NOW + ::conf.keepalive); |
596 |
|
597 |
// send queued packets |
598 |
if (ictx && octx) |
599 |
{ |
600 |
while (tap_packet *p = (tap_packet *)data_queue.get ()) |
601 |
{ |
602 |
send_data_packet (p); |
603 |
delete p; |
604 |
} |
605 |
|
606 |
while (vpn_packet *p = (vpn_packet *)vpn_queue.get ()) |
607 |
{ |
608 |
send_vpn_packet (p, si, IPTOS_RELIABILITY); |
609 |
delete p; |
610 |
} |
611 |
} |
612 |
} |
613 |
else |
614 |
{ |
615 |
retry_cnt = 0; |
616 |
establish_connection.start (NOW + 5); |
617 |
keepalive.stop (); |
618 |
rekey.stop (); |
619 |
} |
620 |
} |
621 |
|
622 |
void |
623 |
connection::reset_si () |
624 |
{ |
625 |
protocol = best_protocol (THISNODE->protocols & conf->protocols); |
626 |
|
627 |
// mask out protocols we cannot establish |
628 |
if (!conf->udp_port) protocol &= ~PROT_UDPv4; |
629 |
if (!conf->tcp_port) protocol &= ~PROT_TCPv4; |
630 |
if (!conf->dns_port) protocol &= ~PROT_DNSv4; |
631 |
|
632 |
si.set (conf, protocol); |
633 |
} |
634 |
|
635 |
// ensure sockinfo is valid, forward if necessary |
636 |
const sockinfo & |
637 |
connection::forward_si (const sockinfo &si) const |
638 |
{ |
639 |
if (!si.valid ()) |
640 |
{ |
641 |
connection *r = vpn->find_router (); |
642 |
|
643 |
if (r) |
644 |
{ |
645 |
slog (L_DEBUG, _("%s: no common protocol, trying indirectly through %s (%s)"), |
646 |
conf->nodename, r->conf->nodename, (const char *)r->si); |
647 |
return r->si; |
648 |
} |
649 |
else |
650 |
slog (L_DEBUG, _("%s: node unreachable, no common protocol"), |
651 |
conf->nodename); |
652 |
} |
653 |
|
654 |
return si; |
655 |
} |
656 |
|
657 |
void |
658 |
connection::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
659 |
{ |
660 |
if (!vpn->send_vpn_packet (pkt, si, tos)) |
661 |
reset_connection (); |
662 |
} |
663 |
|
664 |
void |
665 |
connection::send_ping (const sockinfo &si, u8 pong) |
666 |
{ |
667 |
ping_packet *pkt = new ping_packet; |
668 |
|
669 |
pkt->setup (conf->id, pong ? ping_packet::PT_PONG : ping_packet::PT_PING); |
670 |
send_vpn_packet (pkt, si, IPTOS_LOWDELAY); |
671 |
|
672 |
delete pkt; |
673 |
} |
674 |
|
675 |
void |
676 |
connection::send_reset (const sockinfo &si) |
677 |
{ |
678 |
if (reset_rate_limiter.can (si) && connectmode != conf_node::C_DISABLED) |
679 |
{ |
680 |
config_packet *pkt = new config_packet; |
681 |
|
682 |
pkt->setup (vpn_packet::PT_RESET, conf->id); |
683 |
send_vpn_packet (pkt, si, IPTOS_MINCOST); |
684 |
|
685 |
delete pkt; |
686 |
} |
687 |
} |
688 |
|
689 |
void |
690 |
connection::send_auth_request (const sockinfo &si, bool initiate) |
691 |
{ |
692 |
auth_req_packet *pkt = new auth_req_packet (conf->id, initiate, THISNODE->protocols); |
693 |
|
694 |
rsachallenge chg; |
695 |
rsa_cache.gen (pkt->id, chg); |
696 |
rsa_encrypt (conf->rsa_key, chg, pkt->encr); |
697 |
|
698 |
slog (L_TRACE, ">>%d PT_AUTH_REQ [%s]", conf->id, (const char *)si); |
699 |
|
700 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY | IPTOS_LOWDELAY); // rsa is very very costly |
701 |
|
702 |
delete pkt; |
703 |
} |
704 |
|
705 |
void |
706 |
connection::send_auth_response (const sockinfo &si, const rsaid &id, const rsachallenge &chg) |
707 |
{ |
708 |
auth_res_packet *pkt = new auth_res_packet (conf->id); |
709 |
|
710 |
pkt->id = id; |
711 |
|
712 |
rsa_hash (id, chg, pkt->response); |
713 |
|
714 |
pkt->hmac_set (octx); |
715 |
|
716 |
slog (L_TRACE, ">>%d PT_AUTH_RES [%s]", conf->id, (const char *)si); |
717 |
|
718 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly |
719 |
|
720 |
delete pkt; |
721 |
} |
722 |
|
723 |
void |
724 |
connection::send_connect_info (int rid, const sockinfo &rsi, u8 rprotocols) |
725 |
{ |
726 |
slog (L_TRACE, ">>%d PT_CONNECT_INFO(%d,%s)\n", |
727 |
conf->id, rid, (const char *)rsi); |
728 |
|
729 |
connect_info_packet *r = new connect_info_packet (conf->id, rid, rsi, rprotocols); |
730 |
|
731 |
r->hmac_set (octx); |
732 |
send_vpn_packet (r, si); |
733 |
|
734 |
delete r; |
735 |
} |
736 |
|
737 |
void |
738 |
connection::establish_connection_cb (time_watcher &w) |
739 |
{ |
740 |
if (!ictx |
741 |
&& conf != THISNODE |
742 |
&& connectmode != conf_node::C_NEVER |
743 |
&& connectmode != conf_node::C_DISABLED |
744 |
&& NOW > w.at) |
745 |
{ |
746 |
w.at = TSTAMP_MAX; // first disable this watcher in case of recursion |
747 |
|
748 |
double retry_int = double (retry_cnt & 3 |
749 |
? (retry_cnt & 3) + 1 |
750 |
: 1 << (retry_cnt >> 2)); |
751 |
|
752 |
reset_si (); |
753 |
|
754 |
bool slow = si.prot & PROT_SLOW; |
755 |
|
756 |
if (si.prot && !si.host) |
757 |
vpn->send_connect_request (conf->id); |
758 |
else |
759 |
{ |
760 |
const sockinfo &dsi = forward_si (si); |
761 |
|
762 |
slow = slow || (dsi.prot & PROT_SLOW); |
763 |
|
764 |
if (dsi.valid () && auth_rate_limiter.can (dsi)) |
765 |
{ |
766 |
if (retry_cnt < 4) |
767 |
send_auth_request (dsi, true); |
768 |
else |
769 |
send_ping (dsi, 0); |
770 |
} |
771 |
} |
772 |
|
773 |
retry_int *= slow ? 8. : 0.7; |
774 |
|
775 |
if (retry_int < conf->max_retry) |
776 |
retry_cnt++; |
777 |
else |
778 |
retry_int = conf->max_retry; |
779 |
|
780 |
w.start (NOW + retry_int); |
781 |
} |
782 |
} |
783 |
|
784 |
void |
785 |
connection::reset_connection () |
786 |
{ |
787 |
if (ictx && octx) |
788 |
{ |
789 |
slog (L_INFO, _("%s(%s): connection lost"), |
790 |
conf->nodename, (const char *)si); |
791 |
|
792 |
if (::conf.script_node_down) |
793 |
run_script (run_script_cb (this, &connection::script_node_down), false); |
794 |
} |
795 |
|
796 |
delete ictx; ictx = 0; |
797 |
delete octx; octx = 0; |
798 |
#if ENABLE_DNS |
799 |
dnsv4_reset_connection (); |
800 |
#endif |
801 |
|
802 |
si.host = 0; |
803 |
|
804 |
last_activity = 0; |
805 |
retry_cnt = 0; |
806 |
|
807 |
rekey.stop (); |
808 |
keepalive.stop (); |
809 |
establish_connection.stop (); |
810 |
} |
811 |
|
812 |
void |
813 |
connection::shutdown () |
814 |
{ |
815 |
if (ictx && octx) |
816 |
send_reset (si); |
817 |
|
818 |
reset_connection (); |
819 |
} |
820 |
|
821 |
void |
822 |
connection::rekey_cb (time_watcher &w) |
823 |
{ |
824 |
reset_connection (); |
825 |
establish_connection (); |
826 |
} |
827 |
|
828 |
void |
829 |
connection::send_data_packet (tap_packet *pkt) |
830 |
{ |
831 |
vpndata_packet *p = new vpndata_packet; |
832 |
int tos = 0; |
833 |
|
834 |
// I am not hilarious about peeking into packets, but so be it. |
835 |
if (conf->inherit_tos && pkt->is_ipv4 ()) |
836 |
tos = (*pkt)[15] & IPTOS_TOS_MASK; |
837 |
|
838 |
p->setup (this, conf->id, &((*pkt)[6 + 6]), pkt->len - 6 - 6, ++oseqno); // skip 2 macs |
839 |
send_vpn_packet (p, si, tos); |
840 |
|
841 |
delete p; |
842 |
|
843 |
if (oseqno > MAX_SEQNO) |
844 |
rekey (); |
845 |
} |
846 |
|
847 |
void |
848 |
connection::inject_data_packet (tap_packet *pkt, bool broadcast/*TODO DDD*/) |
849 |
{ |
850 |
if (ictx && octx) |
851 |
send_data_packet (pkt); |
852 |
else |
853 |
{ |
854 |
if (!broadcast)//DDDD |
855 |
data_queue.put (new tap_packet (*pkt)); |
856 |
|
857 |
establish_connection (); |
858 |
} |
859 |
} |
860 |
|
861 |
void connection::inject_vpn_packet (vpn_packet *pkt, int tos) |
862 |
{ |
863 |
if (ictx && octx) |
864 |
send_vpn_packet (pkt, si, tos); |
865 |
else |
866 |
{ |
867 |
vpn_queue.put ((vpn_packet *)new data_packet (*(data_packet *)pkt)); |
868 |
|
869 |
establish_connection (); |
870 |
} |
871 |
} |
872 |
|
873 |
void |
874 |
connection::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi) |
875 |
{ |
876 |
last_activity = NOW; |
877 |
|
878 |
slog (L_NOISE, "<<%d received packet type %d from %d to %d", |
879 |
conf->id, pkt->typ (), pkt->src (), pkt->dst ()); |
880 |
|
881 |
switch (pkt->typ ()) |
882 |
{ |
883 |
case vpn_packet::PT_PING: |
884 |
// we send pings instead of auth packets after some retries, |
885 |
// so reset the retry counter and establish a connection |
886 |
// when we receive a ping. |
887 |
if (!ictx) |
888 |
{ |
889 |
if (auth_rate_limiter.can (rsi)) |
890 |
send_auth_request (rsi, true); |
891 |
} |
892 |
else |
893 |
send_ping (rsi, 1); // pong |
894 |
|
895 |
break; |
896 |
|
897 |
case vpn_packet::PT_PONG: |
898 |
break; |
899 |
|
900 |
case vpn_packet::PT_RESET: |
901 |
{ |
902 |
reset_connection (); |
903 |
|
904 |
config_packet *p = (config_packet *) pkt; |
905 |
|
906 |
if (!p->chk_config ()) |
907 |
{ |
908 |
slog (L_WARN, _("%s(%s): protocol mismatch, disabling node"), |
909 |
conf->nodename, (const char *)rsi); |
910 |
connectmode = conf_node::C_DISABLED; |
911 |
} |
912 |
else if (connectmode == conf_node::C_ALWAYS) |
913 |
establish_connection (); |
914 |
} |
915 |
break; |
916 |
|
917 |
case vpn_packet::PT_AUTH_REQ: |
918 |
if (auth_rate_limiter.can (rsi)) |
919 |
{ |
920 |
auth_req_packet *p = (auth_req_packet *) pkt; |
921 |
|
922 |
slog (L_TRACE, "<<%d PT_AUTH_REQ(%d)", conf->id, p->initiate); |
923 |
|
924 |
if (p->chk_config () && !strncmp (p->magic, MAGIC, 8)) |
925 |
{ |
926 |
if (p->prot_minor != PROTOCOL_MINOR) |
927 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
928 |
conf->nodename, (const char *)rsi, |
929 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
930 |
|
931 |
if (p->initiate) |
932 |
send_auth_request (rsi, false); |
933 |
|
934 |
rsachallenge k; |
935 |
|
936 |
if (!rsa_decrypt (::conf.rsa_key, p->encr, k)) |
937 |
{ |
938 |
slog (L_ERR, _("%s(%s): challenge illegal or corrupted (%s). mismatched key or config file?"), |
939 |
conf->nodename, (const char *)rsi, ERR_error_string (ERR_get_error (), 0)); |
940 |
break; |
941 |
} |
942 |
else |
943 |
{ |
944 |
delete octx; |
945 |
|
946 |
octx = new crypto_ctx (k, 1); |
947 |
oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff; |
948 |
|
949 |
conf->protocols = p->protocols; |
950 |
features = p->features & config_packet::get_features (); |
951 |
|
952 |
send_auth_response (rsi, p->id, k); |
953 |
|
954 |
connection_established (); |
955 |
|
956 |
break; |
957 |
} |
958 |
} |
959 |
else |
960 |
slog (L_WARN, _("%s(%s): protocol mismatch"), |
961 |
conf->nodename, (const char *)rsi); |
962 |
|
963 |
send_reset (rsi); |
964 |
} |
965 |
|
966 |
break; |
967 |
|
968 |
case vpn_packet::PT_AUTH_RES: |
969 |
{ |
970 |
auth_res_packet *p = (auth_res_packet *) pkt; |
971 |
|
972 |
slog (L_TRACE, "<<%d PT_AUTH_RES", conf->id); |
973 |
|
974 |
if (p->chk_config ()) |
975 |
{ |
976 |
if (p->prot_minor != PROTOCOL_MINOR) |
977 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
978 |
conf->nodename, (const char *)rsi, |
979 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
980 |
|
981 |
rsachallenge chg; |
982 |
|
983 |
if (!rsa_cache.find (p->id, chg)) |
984 |
{ |
985 |
slog (L_ERR, _("%s(%s): unrequested auth response ignored"), |
986 |
conf->nodename, (const char *)rsi); |
987 |
break; |
988 |
} |
989 |
else |
990 |
{ |
991 |
crypto_ctx *cctx = new crypto_ctx (chg, 0); |
992 |
|
993 |
if (!p->hmac_chk (cctx)) |
994 |
{ |
995 |
slog (L_ERR, _("%s(%s): hmac authentication error on auth response, received invalid packet\n" |
996 |
"could be an attack, or just corruption or a synchronization error"), |
997 |
conf->nodename, (const char *)rsi); |
998 |
break; |
999 |
} |
1000 |
else |
1001 |
{ |
1002 |
rsaresponse h; |
1003 |
|
1004 |
rsa_hash (p->id, chg, h); |
1005 |
|
1006 |
if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h)) |
1007 |
{ |
1008 |
prot_minor = p->prot_minor; |
1009 |
|
1010 |
delete ictx; ictx = cctx; |
1011 |
|
1012 |
iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid |
1013 |
|
1014 |
si = rsi; |
1015 |
protocol = rsi.prot; |
1016 |
|
1017 |
connection_established (); |
1018 |
|
1019 |
slog (L_INFO, _("%s(%s): connection established, protocol version %d.%d"), |
1020 |
conf->nodename, (const char *)rsi, |
1021 |
p->prot_major, p->prot_minor); |
1022 |
|
1023 |
if (::conf.script_node_up) |
1024 |
run_script (run_script_cb (this, &connection::script_node_up), false); |
1025 |
|
1026 |
break; |
1027 |
} |
1028 |
else |
1029 |
slog (L_ERR, _("%s(%s): sent and received challenge do not match"), |
1030 |
conf->nodename, (const char *)rsi); |
1031 |
} |
1032 |
|
1033 |
delete cctx; |
1034 |
} |
1035 |
} |
1036 |
} |
1037 |
|
1038 |
send_reset (rsi); |
1039 |
break; |
1040 |
|
1041 |
case vpn_packet::PT_DATA_COMPRESSED: |
1042 |
#if !ENABLE_COMPRESSION |
1043 |
send_reset (rsi); |
1044 |
break; |
1045 |
#endif |
1046 |
|
1047 |
case vpn_packet::PT_DATA_UNCOMPRESSED: |
1048 |
|
1049 |
if (ictx && octx) |
1050 |
{ |
1051 |
vpndata_packet *p = (vpndata_packet *)pkt; |
1052 |
|
1053 |
if (!p->hmac_chk (ictx)) |
1054 |
slog (L_ERR, _("%s(%s): hmac authentication error, received invalid packet\n" |
1055 |
"could be an attack, or just corruption or a synchronization error"), |
1056 |
conf->nodename, (const char *)rsi); |
1057 |
else |
1058 |
{ |
1059 |
u32 seqno; |
1060 |
tap_packet *d = p->unpack (this, seqno); |
1061 |
|
1062 |
if (iseqno.recv_ok (seqno)) |
1063 |
{ |
1064 |
vpn->tap->send (d); |
1065 |
|
1066 |
if (si != rsi) |
1067 |
{ |
1068 |
// fast re-sync on connection changes, useful especially for tcp/ip |
1069 |
si = rsi; |
1070 |
|
1071 |
slog (L_INFO, _("%s(%s): socket address changed to %s"), |
1072 |
conf->nodename, (const char *)si, (const char *)rsi); |
1073 |
} |
1074 |
} |
1075 |
|
1076 |
delete d; |
1077 |
break; |
1078 |
} |
1079 |
} |
1080 |
|
1081 |
send_reset (rsi); |
1082 |
break; |
1083 |
|
1084 |
case vpn_packet::PT_CONNECT_REQ: |
1085 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1086 |
{ |
1087 |
connect_req_packet *p = (connect_req_packet *) pkt; |
1088 |
|
1089 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1090 |
connection *c = vpn->conns[p->id - 1]; |
1091 |
conf->protocols = p->protocols; |
1092 |
|
1093 |
slog (L_TRACE, "<<%d PT_CONNECT_REQ(%d) [%d]\n", |
1094 |
conf->id, p->id, c->ictx && c->octx); |
1095 |
|
1096 |
if (c->ictx && c->octx) |
1097 |
{ |
1098 |
// send connect_info packets to both sides, in case one is |
1099 |
// behind a nat firewall (or both ;) |
1100 |
c->send_connect_info (conf->id, si, conf->protocols); |
1101 |
send_connect_info (c->conf->id, c->si, c->conf->protocols); |
1102 |
} |
1103 |
else |
1104 |
c->establish_connection (); |
1105 |
} |
1106 |
|
1107 |
break; |
1108 |
|
1109 |
case vpn_packet::PT_CONNECT_INFO: |
1110 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1111 |
{ |
1112 |
connect_info_packet *p = (connect_info_packet *)pkt; |
1113 |
|
1114 |
if (p->id > 0 && p->id <= vpn->conns.size ()) // hmac-auth does not mean we accept anything |
1115 |
{ |
1116 |
connection *c = vpn->conns[p->id - 1]; |
1117 |
|
1118 |
c->conf->protocols = p->protocols; |
1119 |
protocol = best_protocol (c->conf->protocols & THISNODE->protocols & p->si.supported_protocols (c->conf)); |
1120 |
p->si.upgrade_protocol (protocol, c->conf); |
1121 |
|
1122 |
slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)", |
1123 |
conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx); |
1124 |
|
1125 |
const sockinfo &dsi = forward_si (p->si); |
1126 |
|
1127 |
if (dsi.valid ()) |
1128 |
c->send_auth_request (dsi, true); |
1129 |
} |
1130 |
} |
1131 |
|
1132 |
break; |
1133 |
|
1134 |
default: |
1135 |
send_reset (rsi); |
1136 |
break; |
1137 |
} |
1138 |
} |
1139 |
|
1140 |
void connection::keepalive_cb (time_watcher &w) |
1141 |
{ |
1142 |
if (NOW >= last_activity + ::conf.keepalive + 30) |
1143 |
{ |
1144 |
reset_connection (); |
1145 |
establish_connection (); |
1146 |
} |
1147 |
else if (NOW < last_activity + ::conf.keepalive) |
1148 |
w.start (last_activity + ::conf.keepalive); |
1149 |
else if (conf->connectmode != conf_node::C_ONDEMAND |
1150 |
|| THISNODE->connectmode != conf_node::C_ONDEMAND) |
1151 |
{ |
1152 |
send_ping (si); |
1153 |
w.start (NOW + 5); |
1154 |
} |
1155 |
else if (NOW < last_activity + ::conf.keepalive + 10) |
1156 |
// hold ondemand connections implicitly a few seconds longer |
1157 |
// should delete octx, though, or something like that ;) |
1158 |
w.start (last_activity + ::conf.keepalive + 10); |
1159 |
else |
1160 |
reset_connection (); |
1161 |
} |
1162 |
|
1163 |
void connection::send_connect_request (int id) |
1164 |
{ |
1165 |
connect_req_packet *p = new connect_req_packet (conf->id, id, conf->protocols); |
1166 |
|
1167 |
slog (L_TRACE, ">>%d PT_CONNECT_REQ(%d)", conf->id, id); |
1168 |
p->hmac_set (octx); |
1169 |
send_vpn_packet (p, si); |
1170 |
|
1171 |
delete p; |
1172 |
} |
1173 |
|
1174 |
void connection::script_node () |
1175 |
{ |
1176 |
vpn->script_if_up (); |
1177 |
|
1178 |
char *env; |
1179 |
asprintf (&env, "DESTID=%d", conf->id); putenv (env); |
1180 |
asprintf (&env, "DESTNODE=%s", conf->nodename); putenv (env); |
1181 |
asprintf (&env, "DESTIP=%s", si.ntoa ()); putenv (env); |
1182 |
asprintf (&env, "DESTPORT=%d", ntohs (si.port)); putenv (env); |
1183 |
} |
1184 |
|
1185 |
const char *connection::script_node_up () |
1186 |
{ |
1187 |
script_node (); |
1188 |
|
1189 |
putenv ("STATE=up"); |
1190 |
|
1191 |
return ::conf.script_node_up ? ::conf.script_node_up : "node-up"; |
1192 |
} |
1193 |
|
1194 |
const char *connection::script_node_down () |
1195 |
{ |
1196 |
script_node (); |
1197 |
|
1198 |
putenv ("STATE=down"); |
1199 |
|
1200 |
return ::conf.script_node_up ? ::conf.script_node_down : "node-down"; |
1201 |
} |
1202 |
|
1203 |
connection::connection (struct vpn *vpn, conf_node *conf) |
1204 |
: vpn(vpn), conf(conf) |
1205 |
, rekey (this, &connection::rekey_cb) |
1206 |
, keepalive (this, &connection::keepalive_cb) |
1207 |
, establish_connection (this, &connection::establish_connection_cb) |
1208 |
#if ENABLE_DNS |
1209 |
, dns (0) |
1210 |
#endif |
1211 |
{ |
1212 |
octx = ictx = 0; |
1213 |
retry_cnt = 0; |
1214 |
|
1215 |
if (!conf->protocols) // make sure some protocol is enabled |
1216 |
conf->protocols = PROT_UDPv4; |
1217 |
|
1218 |
connectmode = conf_node::C_ALWAYS; // initial setting |
1219 |
reset_connection (); |
1220 |
} |
1221 |
|
1222 |
connection::~connection () |
1223 |
{ |
1224 |
shutdown (); |
1225 |
} |
1226 |
|
1227 |
void connection_init () |
1228 |
{ |
1229 |
auth_rate_limiter.clear (); |
1230 |
reset_rate_limiter.clear (); |
1231 |
} |
1232 |
|