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/* |
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connection.C -- manage a single connection |
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|
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This program 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 this program; 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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extern "C" { |
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# include "lzf/lzf.h" |
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} |
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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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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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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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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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EVP_DigestInit (&ctx, RSA_HASH); |
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EVP_DigestUpdate(&ctx, &chg, sizeof chg); |
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EVP_DigestUpdate(&ctx, &id, sizeof id); |
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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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w.at = TSTAMP_CANCEL; |
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else |
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{ |
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w.at = 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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static const double ALPHA = 1. - 1. / 600.; // allow bursts |
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static const double CUTOFF = 10.; // one event every CUTOFF seconds |
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static const double EXPIRE = CUTOFF * 30.; // expire entries after this time |
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static const double MAXDIF = CUTOFF * (1. / (1. - 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 - 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 = MAXDIF; |
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ri.last = NOW; |
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|
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push_front (ri); |
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|
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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 * ALPHA; |
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ri.diff = ri.diff * 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 > CUTOFF; |
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|
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if (dif > MAXDIF) |
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{ |
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ri.pcnt = 1.; |
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ri.diff = 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); |
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|
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return send; |
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} |
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} |
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|
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///////////////////////////////////////////////////////////////////////////// |
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|
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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); |
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|
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memcpy (hmac, hmac_digest, HMACLENGTH); |
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} |
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|
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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); |
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} |
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|
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void vpn_packet::set_hdr (ptype type_, unsigned int dst) |
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{ |
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type = type_; |
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|
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int src = THISNODE->id; |
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|
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src1 = src; |
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srcdst = ((src >> 8) << 4) | (dst >> 8); |
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dst1 = dst; |
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} |
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|
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#define MAXVPNDATA (MAX_MTU - 6 - 6) |
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#define DATAHDR (sizeof (u32) + RAND_SIZE) |
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|
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struct vpndata_packet:vpn_packet |
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{ |
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u8 data[MAXVPNDATA + DATAHDR]; // seqno |
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|
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void setup (connection *conn, int dst, u8 *d, u32 len, u32 seqno); |
319 |
tap_packet *unpack (connection *conn, u32 &seqno); |
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private: |
321 |
|
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const u32 data_hdr_size () const |
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{ |
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return sizeof (vpndata_packet) - sizeof (net_packet) - MAXVPNDATA - DATAHDR; |
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} |
326 |
}; |
327 |
|
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void |
329 |
vpndata_packet::setup (connection *conn, int dst, u8 *d, u32 l, u32 seqno) |
330 |
{ |
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EVP_CIPHER_CTX *cctx = &conn->octx->cctx; |
332 |
int outl = 0, outl2; |
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ptype type = PT_DATA_UNCOMPRESSED; |
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|
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#if ENABLE_COMPRESSION |
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u8 cdata[MAX_MTU]; |
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u32 cl; |
338 |
|
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cl = lzf_compress (d, l, cdata + 2, (l - 2) & ~7); |
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if (cl) |
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{ |
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type = PT_DATA_COMPRESSED; |
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d = cdata; |
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l = cl + 2; |
345 |
|
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d[0] = cl >> 8; |
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d[1] = cl; |
348 |
} |
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#endif |
350 |
|
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EVP_EncryptInit_ex (cctx, 0, 0, 0, 0); |
352 |
|
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struct { |
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#if RAND_SIZE |
355 |
u8 rnd[RAND_SIZE]; |
356 |
#endif |
357 |
u32 seqno; |
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} datahdr; |
359 |
|
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datahdr.seqno = ntohl (seqno); |
361 |
#if RAND_SIZE |
362 |
RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE); |
363 |
#endif |
364 |
|
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EVP_EncryptUpdate (cctx, |
366 |
(unsigned char *) data + outl, &outl2, |
367 |
(unsigned char *) &datahdr, DATAHDR); |
368 |
outl += outl2; |
369 |
|
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EVP_EncryptUpdate (cctx, |
371 |
(unsigned char *) data + outl, &outl2, |
372 |
(unsigned char *) d, l); |
373 |
outl += outl2; |
374 |
|
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EVP_EncryptFinal_ex (cctx, (unsigned char *) data + outl, &outl2); |
376 |
outl += outl2; |
377 |
|
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len = outl + data_hdr_size (); |
379 |
|
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set_hdr (type, dst); |
381 |
|
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hmac_set (conn->octx); |
383 |
} |
384 |
|
385 |
tap_packet * |
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vpndata_packet::unpack (connection *conn, u32 &seqno) |
387 |
{ |
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EVP_CIPHER_CTX *cctx = &conn->ictx->cctx; |
389 |
int outl = 0, outl2; |
390 |
tap_packet *p = new tap_packet; |
391 |
u8 *d; |
392 |
u32 l = len - data_hdr_size (); |
393 |
|
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EVP_DecryptInit_ex (cctx, 0, 0, 0, 0); |
395 |
|
396 |
#if ENABLE_COMPRESSION |
397 |
u8 cdata[MAX_MTU]; |
398 |
|
399 |
if (type == PT_DATA_COMPRESSED) |
400 |
d = cdata; |
401 |
else |
402 |
#endif |
403 |
d = &(*p)[6 + 6 - DATAHDR]; |
404 |
|
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/* this overwrites part of the src mac, but we fix that later */ |
406 |
EVP_DecryptUpdate (cctx, |
407 |
d, &outl2, |
408 |
(unsigned char *)&data, len - data_hdr_size ()); |
409 |
outl += outl2; |
410 |
|
411 |
EVP_DecryptFinal_ex (cctx, (unsigned char *)d + outl, &outl2); |
412 |
outl += outl2; |
413 |
|
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seqno = ntohl (*(u32 *)(d + RAND_SIZE)); |
415 |
|
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id2mac (dst () ? dst() : THISNODE->id, p->dst); |
417 |
id2mac (src (), p->src); |
418 |
|
419 |
#if ENABLE_COMPRESSION |
420 |
if (type == PT_DATA_COMPRESSED) |
421 |
{ |
422 |
u32 cl = (d[DATAHDR] << 8) | d[DATAHDR + 1]; |
423 |
|
424 |
p->len = lzf_decompress (d + DATAHDR + 2, cl < MAX_MTU ? cl : 0, |
425 |
&(*p)[6 + 6], MAX_MTU) |
426 |
+ 6 + 6; |
427 |
} |
428 |
else |
429 |
p->len = outl + (6 + 6 - DATAHDR); |
430 |
#endif |
431 |
|
432 |
return p; |
433 |
} |
434 |
|
435 |
struct ping_packet : vpn_packet |
436 |
{ |
437 |
void setup (int dst, ptype type) |
438 |
{ |
439 |
set_hdr (type, dst); |
440 |
len = sizeof (*this) - sizeof (net_packet); |
441 |
} |
442 |
}; |
443 |
|
444 |
struct config_packet : vpn_packet |
445 |
{ |
446 |
// actually, hmaclen cannot be checked because the hmac |
447 |
// field comes before this data, so peers with other |
448 |
// hmacs simply will not work. |
449 |
u8 prot_major, prot_minor, randsize, hmaclen; |
450 |
u8 flags, challengelen, pad2, pad3; |
451 |
u32 cipher_nid, digest_nid, hmac_nid; |
452 |
|
453 |
const u8 curflags () const |
454 |
{ |
455 |
return 0x80 |
456 |
| (ENABLE_COMPRESSION ? 0x01 : 0x00); |
457 |
} |
458 |
|
459 |
void setup (ptype type, int dst); |
460 |
bool chk_config () const; |
461 |
}; |
462 |
|
463 |
void config_packet::setup (ptype type, int dst) |
464 |
{ |
465 |
prot_major = PROTOCOL_MAJOR; |
466 |
prot_minor = PROTOCOL_MINOR; |
467 |
randsize = RAND_SIZE; |
468 |
hmaclen = HMACLENGTH; |
469 |
flags = curflags (); |
470 |
challengelen = sizeof (rsachallenge); |
471 |
|
472 |
cipher_nid = htonl (EVP_CIPHER_nid (CIPHER)); |
473 |
digest_nid = htonl (EVP_MD_type (RSA_HASH)); |
474 |
hmac_nid = htonl (EVP_MD_type (DIGEST)); |
475 |
|
476 |
len = sizeof (*this) - sizeof (net_packet); |
477 |
set_hdr (type, dst); |
478 |
} |
479 |
|
480 |
bool config_packet::chk_config () const |
481 |
{ |
482 |
if (prot_major != PROTOCOL_MAJOR) |
483 |
slog (L_WARN, _("major version mismatch (%d <=> %d)"), prot_major, PROTOCOL_MAJOR); |
484 |
else if (randsize != RAND_SIZE) |
485 |
slog (L_WARN, _("rand size mismatch (%d <=> %d)"), randsize, RAND_SIZE); |
486 |
else if (hmaclen != HMACLENGTH) |
487 |
slog (L_WARN, _("hmac length mismatch (%d <=> %d)"), hmaclen, HMACLENGTH); |
488 |
else if (flags != curflags ()) |
489 |
slog (L_WARN, _("flag mismatch (%x <=> %x)"), flags, curflags ()); |
490 |
else if (challengelen != sizeof (rsachallenge)) |
491 |
slog (L_WARN, _("challenge length mismatch (%d <=> %d)"), challengelen, sizeof (rsachallenge)); |
492 |
else if (cipher_nid != htonl (EVP_CIPHER_nid (CIPHER))) |
493 |
slog (L_WARN, _("cipher mismatch (%x <=> %x)"), ntohl (cipher_nid), EVP_CIPHER_nid (CIPHER)); |
494 |
else if (digest_nid != htonl (EVP_MD_type (RSA_HASH))) |
495 |
slog (L_WARN, _("digest mismatch (%x <=> %x)"), ntohl (digest_nid), EVP_MD_type (RSA_HASH)); |
496 |
else if (hmac_nid != htonl (EVP_MD_type (DIGEST))) |
497 |
slog (L_WARN, _("hmac mismatch (%x <=> %x)"), ntohl (hmac_nid), EVP_MD_type (DIGEST)); |
498 |
else |
499 |
return true; |
500 |
|
501 |
return false; |
502 |
} |
503 |
|
504 |
struct auth_req_packet : config_packet |
505 |
{ |
506 |
char magic[8]; |
507 |
u8 initiate; // false if this is just an automatic reply |
508 |
u8 protocols; // supported protocols (will get patches on forward) |
509 |
u8 pad2, pad3; |
510 |
rsaid id; |
511 |
rsaencrdata encr; |
512 |
|
513 |
auth_req_packet (int dst, bool initiate_, u8 protocols_) |
514 |
{ |
515 |
config_packet::setup (PT_AUTH_REQ, dst); |
516 |
strncpy (magic, MAGIC, 8); |
517 |
initiate = !!initiate_; |
518 |
protocols = protocols_; |
519 |
|
520 |
len = sizeof (*this) - sizeof (net_packet); |
521 |
} |
522 |
}; |
523 |
|
524 |
struct auth_res_packet : config_packet |
525 |
{ |
526 |
rsaid id; |
527 |
u8 pad1, pad2, pad3; |
528 |
u8 response_len; // encrypted length |
529 |
rsaresponse response; |
530 |
|
531 |
auth_res_packet (int dst) |
532 |
{ |
533 |
config_packet::setup (PT_AUTH_RES, dst); |
534 |
|
535 |
len = sizeof (*this) - sizeof (net_packet); |
536 |
} |
537 |
}; |
538 |
|
539 |
struct connect_req_packet : vpn_packet |
540 |
{ |
541 |
u8 id, protocols; |
542 |
u8 pad1, pad2; |
543 |
|
544 |
connect_req_packet (int dst, int id_, u8 protocols_) |
545 |
: id(id_) |
546 |
, protocols(protocols_) |
547 |
{ |
548 |
set_hdr (PT_CONNECT_REQ, dst); |
549 |
len = sizeof (*this) - sizeof (net_packet); |
550 |
} |
551 |
}; |
552 |
|
553 |
struct connect_info_packet : vpn_packet |
554 |
{ |
555 |
u8 id, protocols; |
556 |
u8 pad1, pad2; |
557 |
sockinfo si; |
558 |
|
559 |
connect_info_packet (int dst, int id_, const sockinfo &si_, u8 protocols_) |
560 |
: id(id_) |
561 |
, protocols(protocols_) |
562 |
, si(si_) |
563 |
{ |
564 |
set_hdr (PT_CONNECT_INFO, dst); |
565 |
|
566 |
len = sizeof (*this) - sizeof (net_packet); |
567 |
} |
568 |
}; |
569 |
|
570 |
///////////////////////////////////////////////////////////////////////////// |
571 |
|
572 |
void |
573 |
connection::connection_established () |
574 |
{ |
575 |
if (ictx && octx) |
576 |
{ |
577 |
connectmode = conf->connectmode; |
578 |
|
579 |
rekey.start (NOW + ::conf.rekey); |
580 |
keepalive.start (NOW + ::conf.keepalive); |
581 |
|
582 |
// send queued packets |
583 |
if (ictx && octx) |
584 |
{ |
585 |
while (tap_packet *p = (tap_packet *)data_queue.get ()) |
586 |
{ |
587 |
send_data_packet (p); |
588 |
delete p; |
589 |
} |
590 |
|
591 |
while (vpn_packet *p = (vpn_packet *)vpn_queue.get ()) |
592 |
{ |
593 |
send_vpn_packet (p, si, IPTOS_RELIABILITY); |
594 |
delete p; |
595 |
} |
596 |
} |
597 |
} |
598 |
else |
599 |
{ |
600 |
retry_cnt = 0; |
601 |
establish_connection.start (NOW + 5); |
602 |
keepalive.reset (); |
603 |
rekey.reset (); |
604 |
} |
605 |
} |
606 |
|
607 |
void |
608 |
connection::reset_si () |
609 |
{ |
610 |
protocol = best_protocol (THISNODE->protocols & conf->protocols); |
611 |
|
612 |
// mask out protocols we cannot establish |
613 |
if (!conf->udp_port) protocol &= ~PROT_UDPv4; |
614 |
if (!conf->tcp_port) protocol &= ~PROT_TCPv4; |
615 |
|
616 |
si.set (conf, protocol); |
617 |
} |
618 |
|
619 |
// ensure sockinfo is valid, forward if necessary |
620 |
const sockinfo & |
621 |
connection::forward_si (const sockinfo &si) const |
622 |
{ |
623 |
if (!si.valid ()) |
624 |
{ |
625 |
connection *r = vpn->find_router (); |
626 |
|
627 |
if (r) |
628 |
{ |
629 |
slog (L_DEBUG, _("%s: no common protocol, trying indirectly through %s"), |
630 |
conf->nodename, r->conf->nodename); |
631 |
return r->si; |
632 |
} |
633 |
else |
634 |
slog (L_DEBUG, _("%s: node unreachable, no common protocol"), |
635 |
conf->nodename); |
636 |
} |
637 |
|
638 |
return si; |
639 |
} |
640 |
|
641 |
void |
642 |
connection::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
643 |
{ |
644 |
if (!vpn->send_vpn_packet (pkt, si, tos)) |
645 |
reset_connection (); |
646 |
} |
647 |
|
648 |
void |
649 |
connection::send_ping (const sockinfo &si, u8 pong) |
650 |
{ |
651 |
ping_packet *pkt = new ping_packet; |
652 |
|
653 |
pkt->setup (conf->id, pong ? ping_packet::PT_PONG : ping_packet::PT_PING); |
654 |
send_vpn_packet (pkt, si, IPTOS_LOWDELAY); |
655 |
|
656 |
delete pkt; |
657 |
} |
658 |
|
659 |
void |
660 |
connection::send_reset (const sockinfo &si) |
661 |
{ |
662 |
if (reset_rate_limiter.can (si) && connectmode != conf_node::C_DISABLED) |
663 |
{ |
664 |
config_packet *pkt = new config_packet; |
665 |
|
666 |
pkt->setup (vpn_packet::PT_RESET, conf->id); |
667 |
send_vpn_packet (pkt, si, IPTOS_MINCOST); |
668 |
|
669 |
delete pkt; |
670 |
} |
671 |
} |
672 |
|
673 |
void |
674 |
connection::send_auth_request (const sockinfo &si, bool initiate) |
675 |
{ |
676 |
auth_req_packet *pkt = new auth_req_packet (conf->id, initiate, THISNODE->protocols); |
677 |
|
678 |
rsachallenge chg; |
679 |
|
680 |
rsa_cache.gen (pkt->id, chg); |
681 |
|
682 |
if (0 > RSA_public_encrypt (sizeof chg, |
683 |
(unsigned char *)&chg, (unsigned char *)&pkt->encr, |
684 |
conf->rsa_key, RSA_PKCS1_OAEP_PADDING)) |
685 |
fatal ("RSA_public_encrypt error"); |
686 |
|
687 |
slog (L_TRACE, ">>%d PT_AUTH_REQ [%s]", conf->id, (const char *)si); |
688 |
|
689 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY | IPTOS_LOWDELAY); // rsa is very very costly |
690 |
|
691 |
delete pkt; |
692 |
} |
693 |
|
694 |
void |
695 |
connection::send_auth_response (const sockinfo &si, const rsaid &id, const rsachallenge &chg) |
696 |
{ |
697 |
auth_res_packet *pkt = new auth_res_packet (conf->id); |
698 |
|
699 |
pkt->id = id; |
700 |
|
701 |
rsa_hash (id, chg, pkt->response); |
702 |
|
703 |
pkt->hmac_set (octx); |
704 |
|
705 |
slog (L_TRACE, ">>%d PT_AUTH_RES [%s]", conf->id, (const char *)si); |
706 |
|
707 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly |
708 |
|
709 |
delete pkt; |
710 |
} |
711 |
|
712 |
void |
713 |
connection::send_connect_info (int rid, const sockinfo &rsi, u8 rprotocols) |
714 |
{ |
715 |
slog (L_TRACE, ">>%d PT_CONNECT_INFO(%d,%s)\n", |
716 |
conf->id, rid, (const char *)rsi); |
717 |
|
718 |
connect_info_packet *r = new connect_info_packet (conf->id, rid, rsi, rprotocols); |
719 |
|
720 |
r->hmac_set (octx); |
721 |
send_vpn_packet (r, si); |
722 |
|
723 |
delete r; |
724 |
} |
725 |
|
726 |
void |
727 |
connection::establish_connection_cb (time_watcher &w) |
728 |
{ |
729 |
if (ictx || conf == THISNODE |
730 |
|| connectmode == conf_node::C_NEVER |
731 |
|| connectmode == conf_node::C_DISABLED) |
732 |
w.at = TSTAMP_CANCEL; |
733 |
else if (w.at <= NOW) |
734 |
{ |
735 |
double retry_int = double (retry_cnt & 3 ? (retry_cnt & 3) : 1 << (retry_cnt >> 2)) * 0.6; |
736 |
|
737 |
if (retry_int < 3600 * 8) |
738 |
retry_cnt++; |
739 |
|
740 |
w.at = NOW + retry_int; |
741 |
|
742 |
reset_si (); |
743 |
|
744 |
if (si.prot && !si.host) |
745 |
vpn->send_connect_request (conf->id); |
746 |
else |
747 |
{ |
748 |
const sockinfo &dsi = forward_si (si); |
749 |
|
750 |
if (dsi.valid () && auth_rate_limiter.can (dsi)) |
751 |
{ |
752 |
if (retry_cnt < 4) |
753 |
send_auth_request (dsi, true); |
754 |
else |
755 |
send_ping (dsi, 0); |
756 |
} |
757 |
} |
758 |
} |
759 |
} |
760 |
|
761 |
void |
762 |
connection::reset_connection () |
763 |
{ |
764 |
if (ictx && octx) |
765 |
{ |
766 |
slog (L_INFO, _("%s(%s): connection lost"), |
767 |
conf->nodename, (const char *)si); |
768 |
|
769 |
if (::conf.script_node_down) |
770 |
run_script (run_script_cb (this, &connection::script_node_down), false); |
771 |
} |
772 |
|
773 |
delete ictx; ictx = 0; |
774 |
delete octx; octx = 0; |
775 |
|
776 |
si.host= 0; |
777 |
|
778 |
last_activity = 0; |
779 |
retry_cnt = 0; |
780 |
|
781 |
rekey.reset (); |
782 |
keepalive.reset (); |
783 |
establish_connection.reset (); |
784 |
} |
785 |
|
786 |
void |
787 |
connection::shutdown () |
788 |
{ |
789 |
if (ictx && octx) |
790 |
send_reset (si); |
791 |
|
792 |
reset_connection (); |
793 |
} |
794 |
|
795 |
void |
796 |
connection::rekey_cb (time_watcher &w) |
797 |
{ |
798 |
w.at = TSTAMP_CANCEL; |
799 |
|
800 |
reset_connection (); |
801 |
establish_connection (); |
802 |
} |
803 |
|
804 |
void |
805 |
connection::send_data_packet (tap_packet *pkt, bool broadcast) |
806 |
{ |
807 |
vpndata_packet *p = new vpndata_packet; |
808 |
int tos = 0; |
809 |
|
810 |
// I am not hilarious about peeking into packets, but so be it. |
811 |
if (conf->inherit_tos |
812 |
&& (*pkt)[12] == 0x08 && (*pkt)[13] == 0x00 // IP |
813 |
&& ((*pkt)[14] & 0xf0) == 0x40) // IPv4 |
814 |
tos = (*pkt)[15] & IPTOS_TOS_MASK; |
815 |
|
816 |
p->setup (this, broadcast ? 0 : conf->id, &((*pkt)[6 + 6]), pkt->len - 6 - 6, ++oseqno); // skip 2 macs |
817 |
send_vpn_packet (p, si, tos); |
818 |
|
819 |
delete p; |
820 |
|
821 |
if (oseqno > MAX_SEQNO) |
822 |
rekey (); |
823 |
} |
824 |
|
825 |
void |
826 |
connection::inject_data_packet (tap_packet *pkt, bool broadcast) |
827 |
{ |
828 |
if (ictx && octx) |
829 |
send_data_packet (pkt, broadcast); |
830 |
else |
831 |
{ |
832 |
if (!broadcast)//DDDD |
833 |
data_queue.put (new tap_packet (*pkt)); |
834 |
|
835 |
establish_connection (); |
836 |
} |
837 |
} |
838 |
|
839 |
void connection::inject_vpn_packet (vpn_packet *pkt, int tos) |
840 |
{ |
841 |
if (ictx && octx) |
842 |
send_vpn_packet (pkt, si, tos); |
843 |
else |
844 |
{ |
845 |
vpn_queue.put (new vpn_packet (*pkt)); |
846 |
|
847 |
establish_connection (); |
848 |
} |
849 |
} |
850 |
|
851 |
void |
852 |
connection::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi) |
853 |
{ |
854 |
last_activity = NOW; |
855 |
|
856 |
slog (L_NOISE, "<<%d received packet type %d from %d to %d", |
857 |
conf->id, pkt->typ (), pkt->src (), pkt->dst ()); |
858 |
|
859 |
switch (pkt->typ ()) |
860 |
{ |
861 |
case vpn_packet::PT_PING: |
862 |
// we send pings instead of auth packets after some retries, |
863 |
// so reset the retry counter and establish a connection |
864 |
// when we receive a ping. |
865 |
if (!ictx) |
866 |
{ |
867 |
if (auth_rate_limiter.can (rsi)) |
868 |
send_auth_request (rsi, true); |
869 |
} |
870 |
else |
871 |
send_ping (rsi, 1); // pong |
872 |
|
873 |
break; |
874 |
|
875 |
case vpn_packet::PT_PONG: |
876 |
break; |
877 |
|
878 |
case vpn_packet::PT_RESET: |
879 |
{ |
880 |
reset_connection (); |
881 |
|
882 |
config_packet *p = (config_packet *) pkt; |
883 |
|
884 |
if (!p->chk_config ()) |
885 |
{ |
886 |
slog (L_WARN, _("%s(%s): protocol mismatch, disabling node"), |
887 |
conf->nodename, (const char *)rsi); |
888 |
connectmode = conf_node::C_DISABLED; |
889 |
} |
890 |
else if (connectmode == conf_node::C_ALWAYS) |
891 |
establish_connection (); |
892 |
} |
893 |
break; |
894 |
|
895 |
case vpn_packet::PT_AUTH_REQ: |
896 |
if (auth_rate_limiter.can (rsi)) |
897 |
{ |
898 |
auth_req_packet *p = (auth_req_packet *) pkt; |
899 |
|
900 |
slog (L_TRACE, "<<%d PT_AUTH_REQ(%d)", conf->id, p->initiate); |
901 |
|
902 |
if (p->chk_config () && !strncmp (p->magic, MAGIC, 8)) |
903 |
{ |
904 |
if (p->prot_minor != PROTOCOL_MINOR) |
905 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
906 |
conf->nodename, (const char *)rsi, |
907 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
908 |
|
909 |
if (p->initiate) |
910 |
send_auth_request (rsi, false); |
911 |
|
912 |
rsachallenge k; |
913 |
|
914 |
if (0 > RSA_private_decrypt (sizeof (p->encr), |
915 |
(unsigned char *)&p->encr, (unsigned char *)&k, |
916 |
::conf.rsa_key, RSA_PKCS1_OAEP_PADDING)) |
917 |
slog (L_ERR, _("%s(%s): challenge illegal or corrupted (%s). mismatched key or config file?"), |
918 |
conf->nodename, (const char *)rsi, ERR_error_string (ERR_get_error (), 0)); |
919 |
else |
920 |
{ |
921 |
delete octx; |
922 |
|
923 |
octx = new crypto_ctx (k, 1); |
924 |
oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff; |
925 |
|
926 |
conf->protocols = p->protocols; |
927 |
|
928 |
send_auth_response (rsi, p->id, k); |
929 |
|
930 |
connection_established (); |
931 |
|
932 |
break; |
933 |
} |
934 |
} |
935 |
else |
936 |
slog (L_WARN, _("%s(%s): protocol mismatch"), |
937 |
conf->nodename, (const char *)rsi); |
938 |
|
939 |
send_reset (rsi); |
940 |
} |
941 |
|
942 |
break; |
943 |
|
944 |
case vpn_packet::PT_AUTH_RES: |
945 |
{ |
946 |
auth_res_packet *p = (auth_res_packet *) pkt; |
947 |
|
948 |
slog (L_TRACE, "<<%d PT_AUTH_RES", conf->id); |
949 |
|
950 |
if (p->chk_config ()) |
951 |
{ |
952 |
if (p->prot_minor != PROTOCOL_MINOR) |
953 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
954 |
conf->nodename, (const char *)rsi, |
955 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
956 |
|
957 |
rsachallenge chg; |
958 |
|
959 |
if (!rsa_cache.find (p->id, chg)) |
960 |
{ |
961 |
slog (L_ERR, _("%s(%s): unrequested auth response ignored"), |
962 |
conf->nodename, (const char *)rsi); |
963 |
break; |
964 |
} |
965 |
else |
966 |
{ |
967 |
crypto_ctx *cctx = new crypto_ctx (chg, 0); |
968 |
|
969 |
if (!p->hmac_chk (cctx)) |
970 |
{ |
971 |
slog (L_ERR, _("%s(%s): hmac authentication error on auth response, received invalid packet\n" |
972 |
"could be an attack, or just corruption or an synchronization error"), |
973 |
conf->nodename, (const char *)rsi); |
974 |
break; |
975 |
} |
976 |
else |
977 |
{ |
978 |
rsaresponse h; |
979 |
|
980 |
rsa_hash (p->id, chg, h); |
981 |
|
982 |
if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h)) |
983 |
{ |
984 |
prot_minor = p->prot_minor; |
985 |
|
986 |
delete ictx; ictx = cctx; |
987 |
|
988 |
iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid |
989 |
|
990 |
si = rsi; |
991 |
protocol = rsi.prot; |
992 |
|
993 |
connection_established (); |
994 |
|
995 |
slog (L_INFO, _("%s(%s): connection established, protocol version %d.%d"), |
996 |
conf->nodename, (const char *)rsi, |
997 |
p->prot_major, p->prot_minor); |
998 |
|
999 |
if (::conf.script_node_up) |
1000 |
run_script (run_script_cb (this, &connection::script_node_up), false); |
1001 |
|
1002 |
break; |
1003 |
} |
1004 |
else |
1005 |
slog (L_ERR, _("%s(%s): sent and received challenge do not match"), |
1006 |
conf->nodename, (const char *)rsi); |
1007 |
} |
1008 |
|
1009 |
delete cctx; |
1010 |
} |
1011 |
} |
1012 |
} |
1013 |
|
1014 |
send_reset (rsi); |
1015 |
break; |
1016 |
|
1017 |
case vpn_packet::PT_DATA_COMPRESSED: |
1018 |
#if !ENABLE_COMPRESSION |
1019 |
send_reset (rsi); |
1020 |
break; |
1021 |
#endif |
1022 |
|
1023 |
case vpn_packet::PT_DATA_UNCOMPRESSED: |
1024 |
|
1025 |
if (ictx && octx) |
1026 |
{ |
1027 |
vpndata_packet *p = (vpndata_packet *)pkt; |
1028 |
|
1029 |
if (!p->hmac_chk (ictx)) |
1030 |
slog (L_ERR, _("%s(%s): hmac authentication error, received invalid packet\n" |
1031 |
"could be an attack, or just corruption or an synchronization error"), |
1032 |
conf->nodename, (const char *)rsi); |
1033 |
else |
1034 |
{ |
1035 |
u32 seqno; |
1036 |
tap_packet *d = p->unpack (this, seqno); |
1037 |
|
1038 |
if (iseqno.recv_ok (seqno)) |
1039 |
{ |
1040 |
vpn->tap->send (d); |
1041 |
|
1042 |
if (p->dst () == 0) // re-broadcast |
1043 |
for (vpn::conns_vector::iterator i = vpn->conns.begin (); i != vpn->conns.end (); ++i) |
1044 |
{ |
1045 |
connection *c = *i; |
1046 |
|
1047 |
if (c->conf != THISNODE && c->conf != conf) |
1048 |
c->inject_data_packet (d); |
1049 |
} |
1050 |
|
1051 |
if (si != rsi) |
1052 |
{ |
1053 |
// fast re-sync on connection changes, useful especially for tcp/ip |
1054 |
si = rsi; |
1055 |
|
1056 |
slog (L_INFO, _("%s(%s): socket address changed to %s"), |
1057 |
conf->nodename, (const char *)si, (const char *)rsi); |
1058 |
} |
1059 |
|
1060 |
delete d; |
1061 |
|
1062 |
break; |
1063 |
} |
1064 |
} |
1065 |
} |
1066 |
|
1067 |
send_reset (rsi); |
1068 |
break; |
1069 |
|
1070 |
case vpn_packet::PT_CONNECT_REQ: |
1071 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1072 |
{ |
1073 |
connect_req_packet *p = (connect_req_packet *) pkt; |
1074 |
|
1075 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1076 |
connection *c = vpn->conns[p->id - 1]; |
1077 |
conf->protocols = p->protocols; |
1078 |
|
1079 |
slog (L_TRACE, "<<%d PT_CONNECT_REQ(%d) [%d]\n", |
1080 |
conf->id, p->id, c->ictx && c->octx); |
1081 |
|
1082 |
if (c->ictx && c->octx) |
1083 |
{ |
1084 |
// send connect_info packets to both sides, in case one is |
1085 |
// behind a nat firewall (or both ;) |
1086 |
c->send_connect_info (conf->id, si, conf->protocols); |
1087 |
send_connect_info (c->conf->id, c->si, c->conf->protocols); |
1088 |
} |
1089 |
else |
1090 |
c->establish_connection (); |
1091 |
} |
1092 |
|
1093 |
break; |
1094 |
|
1095 |
case vpn_packet::PT_CONNECT_INFO: |
1096 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1097 |
{ |
1098 |
connect_info_packet *p = (connect_info_packet *) pkt; |
1099 |
|
1100 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1101 |
|
1102 |
connection *c = vpn->conns[p->id - 1]; |
1103 |
|
1104 |
c->conf->protocols = p->protocols; |
1105 |
protocol = best_protocol (c->conf->protocols & THISNODE->protocols & p->si.supported_protocols (c->conf)); |
1106 |
p->si.upgrade_protocol (protocol, c->conf); |
1107 |
|
1108 |
slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)", |
1109 |
conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx); |
1110 |
|
1111 |
const sockinfo &dsi = forward_si (p->si); |
1112 |
|
1113 |
if (dsi.valid ()) |
1114 |
c->send_auth_request (dsi, true); |
1115 |
} |
1116 |
|
1117 |
break; |
1118 |
|
1119 |
default: |
1120 |
send_reset (rsi); |
1121 |
break; |
1122 |
} |
1123 |
} |
1124 |
|
1125 |
void connection::keepalive_cb (time_watcher &w) |
1126 |
{ |
1127 |
if (NOW >= last_activity + ::conf.keepalive + 30) |
1128 |
{ |
1129 |
reset_connection (); |
1130 |
establish_connection (); |
1131 |
} |
1132 |
else if (NOW < last_activity + ::conf.keepalive) |
1133 |
w.at = last_activity + ::conf.keepalive; |
1134 |
else if (conf->connectmode != conf_node::C_ONDEMAND |
1135 |
|| THISNODE->connectmode != conf_node::C_ONDEMAND) |
1136 |
{ |
1137 |
send_ping (si); |
1138 |
w.at = NOW + 5; |
1139 |
} |
1140 |
else if (NOW < last_activity + ::conf.keepalive + 10) |
1141 |
// hold ondemand connections implicitly a few seconds longer |
1142 |
// should delete octx, though, or something like that ;) |
1143 |
w.at = last_activity + ::conf.keepalive + 10; |
1144 |
else |
1145 |
reset_connection (); |
1146 |
} |
1147 |
|
1148 |
void connection::send_connect_request (int id) |
1149 |
{ |
1150 |
connect_req_packet *p = new connect_req_packet (conf->id, id, conf->protocols); |
1151 |
|
1152 |
slog (L_TRACE, ">>%d PT_CONNECT_REQ(%d)", conf->id, id); |
1153 |
p->hmac_set (octx); |
1154 |
send_vpn_packet (p, si); |
1155 |
|
1156 |
delete p; |
1157 |
} |
1158 |
|
1159 |
void connection::script_node () |
1160 |
{ |
1161 |
vpn->script_if_up (); |
1162 |
|
1163 |
char *env; |
1164 |
asprintf (&env, "DESTID=%d", conf->id); putenv (env); |
1165 |
asprintf (&env, "DESTNODE=%s", conf->nodename); putenv (env); |
1166 |
asprintf (&env, "DESTIP=%s", si.ntoa ()); putenv (env); |
1167 |
asprintf (&env, "DESTPORT=%d", ntohs (si.port)); putenv (env); |
1168 |
} |
1169 |
|
1170 |
const char *connection::script_node_up () |
1171 |
{ |
1172 |
script_node (); |
1173 |
|
1174 |
putenv ("STATE=up"); |
1175 |
|
1176 |
return ::conf.script_node_up ? ::conf.script_node_up : "node-up"; |
1177 |
} |
1178 |
|
1179 |
const char *connection::script_node_down () |
1180 |
{ |
1181 |
script_node (); |
1182 |
|
1183 |
putenv ("STATE=down"); |
1184 |
|
1185 |
return ::conf.script_node_up ? ::conf.script_node_down : "node-down"; |
1186 |
} |
1187 |
|
1188 |
connection::connection(struct vpn *vpn_) |
1189 |
: vpn(vpn_) |
1190 |
, rekey (this, &connection::rekey_cb) |
1191 |
, keepalive (this, &connection::keepalive_cb) |
1192 |
, establish_connection (this, &connection::establish_connection_cb) |
1193 |
{ |
1194 |
octx = ictx = 0; |
1195 |
retry_cnt = 0; |
1196 |
|
1197 |
connectmode = conf_node::C_ALWAYS; // initial setting |
1198 |
reset_connection (); |
1199 |
} |
1200 |
|
1201 |
connection::~connection () |
1202 |
{ |
1203 |
shutdown (); |
1204 |
} |
1205 |
|
1206 |
void connection_init () |
1207 |
{ |
1208 |
auth_rate_limiter.clear (); |
1209 |
reset_rate_limiter.clear (); |
1210 |
} |
1211 |
|