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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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#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 (tap_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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tap_packet *pkt_queue::get () |
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{ |
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tap_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. / 180.; // 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++; |
259 |
|
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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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} |
297 |
|
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void vpn_packet::set_hdr (ptype type_, unsigned int dst) |
299 |
{ |
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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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} |
308 |
|
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#define MAXVPNDATA (MAX_MTU - 6 - 6) |
310 |
#define DATAHDR (sizeof (u32) + RAND_SIZE) |
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|
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struct vpndata_packet:vpn_packet |
313 |
{ |
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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); |
317 |
tap_packet *unpack (connection *conn, u32 &seqno); |
318 |
private: |
319 |
|
320 |
const u32 data_hdr_size () const |
321 |
{ |
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return sizeof (vpndata_packet) - sizeof (net_packet) - MAXVPNDATA - DATAHDR; |
323 |
} |
324 |
}; |
325 |
|
326 |
void |
327 |
vpndata_packet::setup (connection *conn, int dst, u8 *d, u32 l, u32 seqno) |
328 |
{ |
329 |
EVP_CIPHER_CTX *cctx = &conn->octx->cctx; |
330 |
int outl = 0, outl2; |
331 |
ptype type = PT_DATA_UNCOMPRESSED; |
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|
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#if ENABLE_COMPRESSION |
334 |
u8 cdata[MAX_MTU]; |
335 |
u32 cl; |
336 |
|
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cl = lzf_compress (d, l, cdata + 2, (l - 2) & ~7); |
338 |
if (cl) |
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{ |
340 |
type = PT_DATA_COMPRESSED; |
341 |
d = cdata; |
342 |
l = cl + 2; |
343 |
|
344 |
d[0] = cl >> 8; |
345 |
d[1] = cl; |
346 |
} |
347 |
#endif |
348 |
|
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EVP_EncryptInit_ex (cctx, 0, 0, 0, 0); |
350 |
|
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struct { |
352 |
#if RAND_SIZE |
353 |
u8 rnd[RAND_SIZE]; |
354 |
#endif |
355 |
u32 seqno; |
356 |
} datahdr; |
357 |
|
358 |
datahdr.seqno = ntohl (seqno); |
359 |
#if RAND_SIZE |
360 |
RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE); |
361 |
#endif |
362 |
|
363 |
EVP_EncryptUpdate (cctx, |
364 |
(unsigned char *) data + outl, &outl2, |
365 |
(unsigned char *) &datahdr, DATAHDR); |
366 |
outl += outl2; |
367 |
|
368 |
EVP_EncryptUpdate (cctx, |
369 |
(unsigned char *) data + outl, &outl2, |
370 |
(unsigned char *) d, l); |
371 |
outl += outl2; |
372 |
|
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EVP_EncryptFinal_ex (cctx, (unsigned char *) data + outl, &outl2); |
374 |
outl += outl2; |
375 |
|
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len = outl + data_hdr_size (); |
377 |
|
378 |
set_hdr (type, dst); |
379 |
|
380 |
hmac_set (conn->octx); |
381 |
} |
382 |
|
383 |
tap_packet * |
384 |
vpndata_packet::unpack (connection *conn, u32 &seqno) |
385 |
{ |
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EVP_CIPHER_CTX *cctx = &conn->ictx->cctx; |
387 |
int outl = 0, outl2; |
388 |
tap_packet *p = new tap_packet; |
389 |
u8 *d; |
390 |
u32 l = len - data_hdr_size (); |
391 |
|
392 |
EVP_DecryptInit_ex (cctx, 0, 0, 0, 0); |
393 |
|
394 |
#if ENABLE_COMPRESSION |
395 |
u8 cdata[MAX_MTU]; |
396 |
|
397 |
if (type == PT_DATA_COMPRESSED) |
398 |
d = cdata; |
399 |
else |
400 |
#endif |
401 |
d = &(*p)[6 + 6 - DATAHDR]; |
402 |
|
403 |
/* this overwrites part of the src mac, but we fix that later */ |
404 |
EVP_DecryptUpdate (cctx, |
405 |
d, &outl2, |
406 |
(unsigned char *)&data, len - data_hdr_size ()); |
407 |
outl += outl2; |
408 |
|
409 |
EVP_DecryptFinal_ex (cctx, (unsigned char *)d + outl, &outl2); |
410 |
outl += outl2; |
411 |
|
412 |
seqno = ntohl (*(u32 *)(d + RAND_SIZE)); |
413 |
|
414 |
id2mac (dst () ? dst() : THISNODE->id, p->dst); |
415 |
id2mac (src (), p->src); |
416 |
|
417 |
#if ENABLE_COMPRESSION |
418 |
if (type == PT_DATA_COMPRESSED) |
419 |
{ |
420 |
u32 cl = (d[DATAHDR] << 8) | d[DATAHDR + 1]; |
421 |
|
422 |
p->len = lzf_decompress (d + DATAHDR + 2, cl < MAX_MTU ? cl : 0, |
423 |
&(*p)[6 + 6], MAX_MTU) |
424 |
+ 6 + 6; |
425 |
} |
426 |
else |
427 |
p->len = outl + (6 + 6 - DATAHDR); |
428 |
#endif |
429 |
|
430 |
return p; |
431 |
} |
432 |
|
433 |
struct ping_packet : vpn_packet |
434 |
{ |
435 |
void setup (int dst, ptype type) |
436 |
{ |
437 |
set_hdr (type, dst); |
438 |
len = sizeof (*this) - sizeof (net_packet); |
439 |
} |
440 |
}; |
441 |
|
442 |
struct config_packet : vpn_packet |
443 |
{ |
444 |
// actually, hmaclen cannot be checked because the hmac |
445 |
// field comes before this data, so peers with other |
446 |
// hmacs simply will not work. |
447 |
u8 prot_major, prot_minor, randsize, hmaclen; |
448 |
u8 flags, challengelen, pad2, pad3; |
449 |
u32 cipher_nid, digest_nid, hmac_nid; |
450 |
|
451 |
const u8 curflags () const |
452 |
{ |
453 |
return 0x80 |
454 |
| (ENABLE_COMPRESSION ? 0x01 : 0x00); |
455 |
} |
456 |
|
457 |
void setup (ptype type, int dst); |
458 |
bool chk_config () const; |
459 |
}; |
460 |
|
461 |
void config_packet::setup (ptype type, int dst) |
462 |
{ |
463 |
prot_major = PROTOCOL_MAJOR; |
464 |
prot_minor = PROTOCOL_MINOR; |
465 |
randsize = RAND_SIZE; |
466 |
hmaclen = HMACLENGTH; |
467 |
flags = curflags (); |
468 |
challengelen = sizeof (rsachallenge); |
469 |
|
470 |
cipher_nid = htonl (EVP_CIPHER_nid (CIPHER)); |
471 |
digest_nid = htonl (EVP_MD_type (RSA_HASH)); |
472 |
hmac_nid = htonl (EVP_MD_type (DIGEST)); |
473 |
|
474 |
len = sizeof (*this) - sizeof (net_packet); |
475 |
set_hdr (type, dst); |
476 |
} |
477 |
|
478 |
bool config_packet::chk_config () const |
479 |
{ |
480 |
return prot_major == PROTOCOL_MAJOR |
481 |
&& randsize == RAND_SIZE |
482 |
&& hmaclen == HMACLENGTH |
483 |
&& flags == curflags () |
484 |
&& challengelen == sizeof (rsachallenge) |
485 |
&& cipher_nid == htonl (EVP_CIPHER_nid (CIPHER)) |
486 |
&& digest_nid == htonl (EVP_MD_type (RSA_HASH)) |
487 |
&& hmac_nid == htonl (EVP_MD_type (DIGEST)); |
488 |
} |
489 |
|
490 |
struct auth_req_packet : config_packet |
491 |
{ |
492 |
char magic[8]; |
493 |
u8 initiate; // false if this is just an automatic reply |
494 |
u8 protocols; // supported protocols (will get patches on forward) |
495 |
u8 pad2, pad3; |
496 |
rsaid id; |
497 |
rsaencrdata encr; |
498 |
|
499 |
auth_req_packet (int dst, bool initiate_, u8 protocols_) |
500 |
{ |
501 |
config_packet::setup (PT_AUTH_REQ, dst); |
502 |
strncpy (magic, MAGIC, 8); |
503 |
initiate = !!initiate_; |
504 |
protocols = protocols_; |
505 |
|
506 |
len = sizeof (*this) - sizeof (net_packet); |
507 |
} |
508 |
}; |
509 |
|
510 |
struct auth_res_packet : config_packet |
511 |
{ |
512 |
rsaid id; |
513 |
u8 pad1, pad2, pad3; |
514 |
u8 response_len; // encrypted length |
515 |
rsaresponse response; |
516 |
|
517 |
auth_res_packet (int dst) |
518 |
{ |
519 |
config_packet::setup (PT_AUTH_RES, dst); |
520 |
|
521 |
len = sizeof (*this) - sizeof (net_packet); |
522 |
} |
523 |
}; |
524 |
|
525 |
struct connect_req_packet : vpn_packet |
526 |
{ |
527 |
u8 id, protocols; |
528 |
u8 pad1, pad2; |
529 |
|
530 |
connect_req_packet (int dst, int id_, u8 protocols_) |
531 |
: id(id_) |
532 |
, protocols(protocols_) |
533 |
{ |
534 |
set_hdr (PT_CONNECT_REQ, dst); |
535 |
len = sizeof (*this) - sizeof (net_packet); |
536 |
} |
537 |
}; |
538 |
|
539 |
struct connect_info_packet : vpn_packet |
540 |
{ |
541 |
u8 id, protocols; |
542 |
u8 pad1, pad2; |
543 |
sockinfo si; |
544 |
|
545 |
connect_info_packet (int dst, int id_, const sockinfo &si_, u8 protocols_) |
546 |
: id(id_) |
547 |
, protocols(protocols_) |
548 |
, si(si_) |
549 |
{ |
550 |
set_hdr (PT_CONNECT_INFO, dst); |
551 |
|
552 |
len = sizeof (*this) - sizeof (net_packet); |
553 |
} |
554 |
}; |
555 |
|
556 |
///////////////////////////////////////////////////////////////////////////// |
557 |
|
558 |
void |
559 |
connection::connection_established () |
560 |
{ |
561 |
if (ictx && octx) |
562 |
{ |
563 |
connectmode = conf->connectmode; |
564 |
|
565 |
rekey.start (NOW + ::conf.rekey); |
566 |
keepalive.start (NOW + ::conf.keepalive); |
567 |
|
568 |
// send queued packets |
569 |
if (ictx && octx) |
570 |
while (tap_packet *p = queue.get ()) |
571 |
{ |
572 |
send_data_packet (p); |
573 |
delete p; |
574 |
} |
575 |
} |
576 |
else |
577 |
{ |
578 |
retry_cnt = 0; |
579 |
establish_connection.start (NOW + 5); |
580 |
keepalive.reset (); |
581 |
rekey.reset (); |
582 |
} |
583 |
} |
584 |
|
585 |
void |
586 |
connection::reset_si () |
587 |
{ |
588 |
protocol = best_protocol (THISNODE->protocols & conf->protocols); |
589 |
|
590 |
// mask out protocols we cannot establish |
591 |
if (!conf->udp_port) protocol &= ~PROT_UDPv4; |
592 |
if (!conf->tcp_port) protocol &= ~PROT_TCPv4; |
593 |
|
594 |
si.set (conf, protocol); |
595 |
} |
596 |
|
597 |
// ensure sockinfo is valid, forward if necessary |
598 |
const sockinfo & |
599 |
connection::forward_si (const sockinfo &si) const |
600 |
{ |
601 |
if (!si.valid ()) |
602 |
{ |
603 |
connection *r = vpn->find_router (); |
604 |
|
605 |
if (r) |
606 |
{ |
607 |
slog (L_DEBUG, _("%s: no common protocol, trying indirectly through %s"), |
608 |
conf->nodename, r->conf->nodename); |
609 |
return r->si; |
610 |
} |
611 |
else |
612 |
slog (L_DEBUG, _("%s: node unreachable, no common protocol"), |
613 |
conf->nodename); |
614 |
} |
615 |
|
616 |
return si; |
617 |
} |
618 |
|
619 |
void |
620 |
connection::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
621 |
{ |
622 |
if (!vpn->send_vpn_packet (pkt, si, tos)) |
623 |
reset_connection (); |
624 |
} |
625 |
|
626 |
void |
627 |
connection::send_ping (const sockinfo &si, u8 pong) |
628 |
{ |
629 |
ping_packet *pkt = new ping_packet; |
630 |
|
631 |
pkt->setup (conf->id, pong ? ping_packet::PT_PONG : ping_packet::PT_PING); |
632 |
send_vpn_packet (pkt, si, IPTOS_LOWDELAY); |
633 |
|
634 |
delete pkt; |
635 |
} |
636 |
|
637 |
void |
638 |
connection::send_reset (const sockinfo &si) |
639 |
{ |
640 |
if (reset_rate_limiter.can (si) && connectmode != conf_node::C_DISABLED) |
641 |
{ |
642 |
config_packet *pkt = new config_packet; |
643 |
|
644 |
pkt->setup (vpn_packet::PT_RESET, conf->id); |
645 |
send_vpn_packet (pkt, si, IPTOS_MINCOST); |
646 |
|
647 |
delete pkt; |
648 |
} |
649 |
} |
650 |
|
651 |
void |
652 |
connection::send_auth_request (const sockinfo &si, bool initiate) |
653 |
{ |
654 |
auth_req_packet *pkt = new auth_req_packet (conf->id, initiate, THISNODE->protocols); |
655 |
|
656 |
rsachallenge chg; |
657 |
|
658 |
rsa_cache.gen (pkt->id, chg); |
659 |
|
660 |
if (0 > RSA_public_encrypt (sizeof chg, |
661 |
(unsigned char *)&chg, (unsigned char *)&pkt->encr, |
662 |
conf->rsa_key, RSA_PKCS1_OAEP_PADDING)) |
663 |
fatal ("RSA_public_encrypt error"); |
664 |
|
665 |
slog (L_TRACE, ">>%d PT_AUTH_REQ [%s]", conf->id, (const char *)si); |
666 |
|
667 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY | IPTOS_LOWDELAY); // rsa is very very costly |
668 |
|
669 |
delete pkt; |
670 |
} |
671 |
|
672 |
void |
673 |
connection::send_auth_response (const sockinfo &si, const rsaid &id, const rsachallenge &chg) |
674 |
{ |
675 |
auth_res_packet *pkt = new auth_res_packet (conf->id); |
676 |
|
677 |
pkt->id = id; |
678 |
|
679 |
rsa_hash (id, chg, pkt->response); |
680 |
|
681 |
pkt->hmac_set (octx); |
682 |
|
683 |
slog (L_TRACE, ">>%d PT_AUTH_RES [%s]", conf->id, (const char *)si); |
684 |
|
685 |
send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly |
686 |
|
687 |
delete pkt; |
688 |
} |
689 |
|
690 |
void |
691 |
connection::send_connect_info (int rid, const sockinfo &rsi, u8 rprotocols) |
692 |
{ |
693 |
slog (L_TRACE, ">>%d PT_CONNECT_INFO(%d,%s)\n", |
694 |
conf->id, rid, (const char *)rsi); |
695 |
|
696 |
connect_info_packet *r = new connect_info_packet (conf->id, rid, rsi, rprotocols); |
697 |
|
698 |
r->hmac_set (octx); |
699 |
send_vpn_packet (r, si); |
700 |
|
701 |
delete r; |
702 |
} |
703 |
|
704 |
void |
705 |
connection::establish_connection_cb (time_watcher &w) |
706 |
{ |
707 |
if (ictx || conf == THISNODE |
708 |
|| connectmode == conf_node::C_NEVER |
709 |
|| connectmode == conf_node::C_DISABLED) |
710 |
w.at = TSTAMP_CANCEL; |
711 |
else if (w.at <= NOW) |
712 |
{ |
713 |
double retry_int = double (retry_cnt & 3 ? (retry_cnt & 3) : 1 << (retry_cnt >> 2)) * 0.6; |
714 |
|
715 |
if (retry_int < 3600 * 8) |
716 |
retry_cnt++; |
717 |
|
718 |
w.at = NOW + retry_int; |
719 |
|
720 |
reset_si (); |
721 |
|
722 |
if (si.prot && !si.host) |
723 |
vpn->send_connect_request (conf->id); |
724 |
else |
725 |
{ |
726 |
const sockinfo &dsi = forward_si (si); |
727 |
|
728 |
if (dsi.valid () && auth_rate_limiter.can (dsi)) |
729 |
{ |
730 |
if (retry_cnt < 4) |
731 |
send_auth_request (dsi, true); |
732 |
else |
733 |
send_ping (dsi, 0); |
734 |
} |
735 |
} |
736 |
} |
737 |
} |
738 |
|
739 |
void |
740 |
connection::reset_connection () |
741 |
{ |
742 |
if (ictx && octx) |
743 |
{ |
744 |
slog (L_INFO, _("%s(%s): connection lost"), |
745 |
conf->nodename, (const char *)si); |
746 |
|
747 |
if (::conf.script_node_down) |
748 |
run_script (run_script_cb (this, &connection::script_node_down), false); |
749 |
} |
750 |
|
751 |
delete ictx; ictx = 0; |
752 |
delete octx; octx = 0; |
753 |
|
754 |
si.host= 0; |
755 |
|
756 |
last_activity = 0; |
757 |
retry_cnt = 0; |
758 |
|
759 |
rekey.reset (); |
760 |
keepalive.reset (); |
761 |
establish_connection.reset (); |
762 |
} |
763 |
|
764 |
void |
765 |
connection::shutdown () |
766 |
{ |
767 |
if (ictx && octx) |
768 |
send_reset (si); |
769 |
|
770 |
reset_connection (); |
771 |
} |
772 |
|
773 |
void |
774 |
connection::rekey_cb (time_watcher &w) |
775 |
{ |
776 |
w.at = TSTAMP_CANCEL; |
777 |
|
778 |
reset_connection (); |
779 |
establish_connection (); |
780 |
} |
781 |
|
782 |
void |
783 |
connection::send_data_packet (tap_packet *pkt, bool broadcast) |
784 |
{ |
785 |
vpndata_packet *p = new vpndata_packet; |
786 |
int tos = 0; |
787 |
|
788 |
if (conf->inherit_tos |
789 |
&& (*pkt)[12] == 0x08 && (*pkt)[13] == 0x00 // IP |
790 |
&& ((*pkt)[14] & 0xf0) == 0x40) // IPv4 |
791 |
tos = (*pkt)[15] & IPTOS_TOS_MASK; |
792 |
|
793 |
p->setup (this, broadcast ? 0 : conf->id, &((*pkt)[6 + 6]), pkt->len - 6 - 6, ++oseqno); // skip 2 macs |
794 |
send_vpn_packet (p, si, tos); |
795 |
|
796 |
delete p; |
797 |
|
798 |
if (oseqno > MAX_SEQNO) |
799 |
rekey (); |
800 |
} |
801 |
|
802 |
void |
803 |
connection::inject_data_packet (tap_packet *pkt, bool broadcast) |
804 |
{ |
805 |
if (ictx && octx) |
806 |
send_data_packet (pkt, broadcast); |
807 |
else |
808 |
{ |
809 |
if (!broadcast)//DDDD |
810 |
queue.put (new tap_packet (*pkt)); |
811 |
|
812 |
establish_connection (); |
813 |
} |
814 |
} |
815 |
|
816 |
void connection::inject_vpn_packet (vpn_packet *pkt, int tos) |
817 |
{ |
818 |
if (ictx && octx) |
819 |
send_vpn_packet (pkt, si, tos); |
820 |
else |
821 |
establish_connection (); |
822 |
} |
823 |
|
824 |
void |
825 |
connection::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi) |
826 |
{ |
827 |
last_activity = NOW; |
828 |
|
829 |
slog (L_NOISE, "<<%d received packet type %d from %d to %d", |
830 |
conf->id, pkt->typ (), pkt->src (), pkt->dst ()); |
831 |
|
832 |
switch (pkt->typ ()) |
833 |
{ |
834 |
case vpn_packet::PT_PING: |
835 |
// we send pings instead of auth packets after some retries, |
836 |
// so reset the retry counter and establish a connection |
837 |
// when we receive a ping. |
838 |
if (!ictx) |
839 |
{ |
840 |
if (auth_rate_limiter.can (rsi)) |
841 |
send_auth_request (rsi, true); |
842 |
} |
843 |
else |
844 |
send_ping (rsi, 1); // pong |
845 |
|
846 |
break; |
847 |
|
848 |
case vpn_packet::PT_PONG: |
849 |
break; |
850 |
|
851 |
case vpn_packet::PT_RESET: |
852 |
{ |
853 |
reset_connection (); |
854 |
|
855 |
config_packet *p = (config_packet *) pkt; |
856 |
|
857 |
if (!p->chk_config ()) |
858 |
{ |
859 |
slog (L_WARN, _("%s(%s): protocol mismatch, disabling node"), |
860 |
conf->nodename, (const char *)rsi); |
861 |
connectmode = conf_node::C_DISABLED; |
862 |
} |
863 |
else if (connectmode == conf_node::C_ALWAYS) |
864 |
establish_connection (); |
865 |
} |
866 |
break; |
867 |
|
868 |
case vpn_packet::PT_AUTH_REQ: |
869 |
if (auth_rate_limiter.can (rsi)) |
870 |
{ |
871 |
auth_req_packet *p = (auth_req_packet *) pkt; |
872 |
|
873 |
slog (L_TRACE, "<<%d PT_AUTH_REQ(%d)", conf->id, p->initiate); |
874 |
|
875 |
if (p->chk_config () && !strncmp (p->magic, MAGIC, 8)) |
876 |
{ |
877 |
if (p->prot_minor != PROTOCOL_MINOR) |
878 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
879 |
conf->nodename, (const char *)rsi, |
880 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
881 |
|
882 |
if (p->initiate) |
883 |
send_auth_request (rsi, false); |
884 |
|
885 |
rsachallenge k; |
886 |
|
887 |
if (0 > RSA_private_decrypt (sizeof (p->encr), |
888 |
(unsigned char *)&p->encr, (unsigned char *)&k, |
889 |
::conf.rsa_key, RSA_PKCS1_OAEP_PADDING)) |
890 |
slog (L_ERR, _("%s(%s): challenge illegal or corrupted"), |
891 |
conf->nodename, (const char *)rsi); |
892 |
else |
893 |
{ |
894 |
delete octx; |
895 |
|
896 |
octx = new crypto_ctx (k, 1); |
897 |
oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff; |
898 |
|
899 |
conf->protocols = p->protocols; |
900 |
|
901 |
send_auth_response (rsi, p->id, k); |
902 |
|
903 |
connection_established (); |
904 |
|
905 |
break; |
906 |
} |
907 |
} |
908 |
|
909 |
send_reset (rsi); |
910 |
} |
911 |
|
912 |
break; |
913 |
|
914 |
case vpn_packet::PT_AUTH_RES: |
915 |
{ |
916 |
auth_res_packet *p = (auth_res_packet *) pkt; |
917 |
|
918 |
slog (L_TRACE, "<<%d PT_AUTH_RES", conf->id); |
919 |
|
920 |
if (p->chk_config ()) |
921 |
{ |
922 |
if (p->prot_minor != PROTOCOL_MINOR) |
923 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
924 |
conf->nodename, (const char *)rsi, |
925 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
926 |
|
927 |
rsachallenge chg; |
928 |
|
929 |
if (!rsa_cache.find (p->id, chg)) |
930 |
slog (L_ERR, _("%s(%s): unrequested auth response"), |
931 |
conf->nodename, (const char *)rsi); |
932 |
else |
933 |
{ |
934 |
crypto_ctx *cctx = new crypto_ctx (chg, 0); |
935 |
|
936 |
if (!p->hmac_chk (cctx)) |
937 |
slog (L_ERR, _("%s(%s): hmac authentication error on auth response, received invalid packet\n" |
938 |
"could be an attack, or just corruption or an synchronization error"), |
939 |
conf->nodename, (const char *)rsi); |
940 |
else |
941 |
{ |
942 |
rsaresponse h; |
943 |
|
944 |
rsa_hash (p->id, chg, h); |
945 |
|
946 |
if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h)) |
947 |
{ |
948 |
prot_minor = p->prot_minor; |
949 |
|
950 |
delete ictx; ictx = cctx; |
951 |
|
952 |
iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid |
953 |
|
954 |
si = rsi; |
955 |
protocol = rsi.prot; |
956 |
|
957 |
connection_established (); |
958 |
|
959 |
slog (L_INFO, _("%s(%s): connection established, protocol version %d.%d"), |
960 |
conf->nodename, (const char *)rsi, |
961 |
p->prot_major, p->prot_minor); |
962 |
|
963 |
if (::conf.script_node_up) |
964 |
run_script (run_script_cb (this, &connection::script_node_up), false); |
965 |
|
966 |
break; |
967 |
} |
968 |
else |
969 |
slog (L_ERR, _("%s(%s): sent and received challenge do not match"), |
970 |
conf->nodename, (const char *)rsi); |
971 |
} |
972 |
|
973 |
delete cctx; |
974 |
} |
975 |
} |
976 |
} |
977 |
|
978 |
send_reset (rsi); |
979 |
break; |
980 |
|
981 |
case vpn_packet::PT_DATA_COMPRESSED: |
982 |
#if !ENABLE_COMPRESSION |
983 |
send_reset (rsi); |
984 |
break; |
985 |
#endif |
986 |
|
987 |
case vpn_packet::PT_DATA_UNCOMPRESSED: |
988 |
|
989 |
if (ictx && octx) |
990 |
{ |
991 |
vpndata_packet *p = (vpndata_packet *)pkt; |
992 |
|
993 |
if (!p->hmac_chk (ictx)) |
994 |
slog (L_ERR, _("%s(%s): hmac authentication error, received invalid packet\n" |
995 |
"could be an attack, or just corruption or an synchronization error"), |
996 |
conf->nodename, (const char *)rsi); |
997 |
else |
998 |
{ |
999 |
u32 seqno; |
1000 |
tap_packet *d = p->unpack (this, seqno); |
1001 |
|
1002 |
if (iseqno.recv_ok (seqno)) |
1003 |
{ |
1004 |
vpn->tap->send (d); |
1005 |
|
1006 |
if (p->dst () == 0) // re-broadcast |
1007 |
for (vpn::conns_vector::iterator i = vpn->conns.begin (); i != vpn->conns.end (); ++i) |
1008 |
{ |
1009 |
connection *c = *i; |
1010 |
|
1011 |
if (c->conf != THISNODE && c->conf != conf) |
1012 |
c->inject_data_packet (d); |
1013 |
} |
1014 |
|
1015 |
if (si != rsi) |
1016 |
{ |
1017 |
// fast re-sync on conneciton changes, useful especially for tcp/ip |
1018 |
si = rsi; |
1019 |
|
1020 |
slog (L_INFO, _("%s(%s): socket address changed to %s"), |
1021 |
conf->nodename, (const char *)si, (const char *)rsi); |
1022 |
} |
1023 |
|
1024 |
delete d; |
1025 |
|
1026 |
break; |
1027 |
} |
1028 |
} |
1029 |
} |
1030 |
|
1031 |
send_reset (rsi); |
1032 |
break; |
1033 |
|
1034 |
case vpn_packet::PT_CONNECT_REQ: |
1035 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1036 |
{ |
1037 |
connect_req_packet *p = (connect_req_packet *) pkt; |
1038 |
|
1039 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1040 |
connection *c = vpn->conns[p->id - 1]; |
1041 |
conf->protocols = p->protocols; |
1042 |
|
1043 |
slog (L_TRACE, "<<%d PT_CONNECT_REQ(%d) [%d]\n", |
1044 |
conf->id, p->id, c->ictx && c->octx); |
1045 |
|
1046 |
if (c->ictx && c->octx) |
1047 |
{ |
1048 |
// send connect_info packets to both sides, in case one is |
1049 |
// behind a nat firewall (or both ;) |
1050 |
c->send_connect_info (conf->id, si, conf->protocols); |
1051 |
send_connect_info (c->conf->id, c->si, c->conf->protocols); |
1052 |
} |
1053 |
} |
1054 |
|
1055 |
break; |
1056 |
|
1057 |
case vpn_packet::PT_CONNECT_INFO: |
1058 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
1059 |
{ |
1060 |
connect_info_packet *p = (connect_info_packet *) pkt; |
1061 |
|
1062 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1063 |
|
1064 |
connection *c = vpn->conns[p->id - 1]; |
1065 |
|
1066 |
c->conf->protocols = p->protocols; |
1067 |
protocol = best_protocol (c->conf->protocols & THISNODE->protocols & p->si.supported_protocols (c->conf)); |
1068 |
p->si.upgrade_protocol (protocol, c->conf); |
1069 |
|
1070 |
slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)", |
1071 |
conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx); |
1072 |
|
1073 |
const sockinfo &dsi = forward_si (p->si); |
1074 |
|
1075 |
if (dsi.valid ()) |
1076 |
c->send_auth_request (dsi, true); |
1077 |
} |
1078 |
|
1079 |
break; |
1080 |
|
1081 |
default: |
1082 |
send_reset (rsi); |
1083 |
break; |
1084 |
} |
1085 |
} |
1086 |
|
1087 |
void connection::keepalive_cb (time_watcher &w) |
1088 |
{ |
1089 |
if (NOW >= last_activity + ::conf.keepalive + 30) |
1090 |
{ |
1091 |
reset_connection (); |
1092 |
establish_connection (); |
1093 |
} |
1094 |
else if (NOW < last_activity + ::conf.keepalive) |
1095 |
w.at = last_activity + ::conf.keepalive; |
1096 |
else if (conf->connectmode != conf_node::C_ONDEMAND |
1097 |
|| THISNODE->connectmode != conf_node::C_ONDEMAND) |
1098 |
{ |
1099 |
send_ping (si); |
1100 |
w.at = NOW + 5; |
1101 |
} |
1102 |
else |
1103 |
reset_connection (); |
1104 |
} |
1105 |
|
1106 |
void connection::send_connect_request (int id) |
1107 |
{ |
1108 |
connect_req_packet *p = new connect_req_packet (conf->id, id, conf->protocols); |
1109 |
|
1110 |
slog (L_TRACE, ">>%d PT_CONNECT_REQ(%d)", conf->id, id); |
1111 |
p->hmac_set (octx); |
1112 |
send_vpn_packet (p, si); |
1113 |
|
1114 |
delete p; |
1115 |
} |
1116 |
|
1117 |
void connection::script_node () |
1118 |
{ |
1119 |
vpn->script_if_up (); |
1120 |
|
1121 |
char *env; |
1122 |
asprintf (&env, "DESTID=%d", conf->id); putenv (env); |
1123 |
asprintf (&env, "DESTNODE=%s", conf->nodename); putenv (env); |
1124 |
asprintf (&env, "DESTIP=%s", si.ntoa ()); putenv (env); |
1125 |
asprintf (&env, "DESTPORT=%d", ntohs (si.port)); putenv (env); |
1126 |
} |
1127 |
|
1128 |
const char *connection::script_node_up () |
1129 |
{ |
1130 |
script_node (); |
1131 |
|
1132 |
putenv ("STATE=up"); |
1133 |
|
1134 |
return ::conf.script_node_up ? ::conf.script_node_up : "node-up"; |
1135 |
} |
1136 |
|
1137 |
const char *connection::script_node_down () |
1138 |
{ |
1139 |
script_node (); |
1140 |
|
1141 |
putenv ("STATE=down"); |
1142 |
|
1143 |
return ::conf.script_node_up ? ::conf.script_node_down : "node-down"; |
1144 |
} |
1145 |
|
1146 |
connection::connection(struct vpn *vpn_) |
1147 |
: vpn(vpn_) |
1148 |
, rekey (this, &connection::rekey_cb) |
1149 |
, keepalive (this, &connection::keepalive_cb) |
1150 |
, establish_connection (this, &connection::establish_connection_cb) |
1151 |
{ |
1152 |
octx = ictx = 0; |
1153 |
retry_cnt = 0; |
1154 |
|
1155 |
connectmode = conf_node::C_ALWAYS; // initial setting |
1156 |
reset_connection (); |
1157 |
} |
1158 |
|
1159 |
connection::~connection () |
1160 |
{ |
1161 |
shutdown (); |
1162 |
} |
1163 |
|
1164 |
void connection_init () |
1165 |
{ |
1166 |
auth_rate_limiter.clear (); |
1167 |
reset_rate_limiter.clear (); |
1168 |
} |
1169 |
|