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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. / 90.; // allow bursts |
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static const double CUTOFF = 20.; // one event every CUTOFF seconds |
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static const double EXPIRE = CUTOFF * 30.; // expire entries after this time |
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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 = CUTOFF * (1. / (1. - ALPHA)); |
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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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bool send = ri.diff / ri.pcnt > CUTOFF; |
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|
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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); |
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tap_packet *unpack (connection *conn, u32 &seqno); |
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private: |
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|
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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; |
315 |
} |
316 |
}; |
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|
318 |
void |
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vpndata_packet::setup (connection *conn, int dst, u8 *d, u32 l, u32 seqno) |
320 |
{ |
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EVP_CIPHER_CTX *cctx = &conn->octx->cctx; |
322 |
int outl = 0, outl2; |
323 |
ptype type = PT_DATA_UNCOMPRESSED; |
324 |
|
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#if ENABLE_COMPRESSION |
326 |
u8 cdata[MAX_MTU]; |
327 |
u32 cl; |
328 |
|
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cl = lzf_compress (d, l, cdata + 2, (l - 2) & ~7); |
330 |
if (cl) |
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{ |
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type = PT_DATA_COMPRESSED; |
333 |
d = cdata; |
334 |
l = cl + 2; |
335 |
|
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d[0] = cl >> 8; |
337 |
d[1] = cl; |
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} |
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#endif |
340 |
|
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EVP_EncryptInit_ex (cctx, 0, 0, 0, 0); |
342 |
|
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struct { |
344 |
#if RAND_SIZE |
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u8 rnd[RAND_SIZE]; |
346 |
#endif |
347 |
u32 seqno; |
348 |
} datahdr; |
349 |
|
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datahdr.seqno = ntohl (seqno); |
351 |
#if RAND_SIZE |
352 |
RAND_pseudo_bytes ((unsigned char *) datahdr.rnd, RAND_SIZE); |
353 |
#endif |
354 |
|
355 |
EVP_EncryptUpdate (cctx, |
356 |
(unsigned char *) data + outl, &outl2, |
357 |
(unsigned char *) &datahdr, DATAHDR); |
358 |
outl += outl2; |
359 |
|
360 |
EVP_EncryptUpdate (cctx, |
361 |
(unsigned char *) data + outl, &outl2, |
362 |
(unsigned char *) d, l); |
363 |
outl += outl2; |
364 |
|
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EVP_EncryptFinal_ex (cctx, (unsigned char *) data + outl, &outl2); |
366 |
outl += outl2; |
367 |
|
368 |
len = outl + data_hdr_size (); |
369 |
|
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set_hdr (type, dst); |
371 |
|
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hmac_set (conn->octx); |
373 |
} |
374 |
|
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tap_packet * |
376 |
vpndata_packet::unpack (connection *conn, u32 &seqno) |
377 |
{ |
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EVP_CIPHER_CTX *cctx = &conn->ictx->cctx; |
379 |
int outl = 0, outl2; |
380 |
tap_packet *p = new tap_packet; |
381 |
u8 *d; |
382 |
u32 l = len - data_hdr_size (); |
383 |
|
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EVP_DecryptInit_ex (cctx, 0, 0, 0, 0); |
385 |
|
386 |
#if ENABLE_COMPRESSION |
387 |
u8 cdata[MAX_MTU]; |
388 |
|
389 |
if (type == PT_DATA_COMPRESSED) |
390 |
d = cdata; |
391 |
else |
392 |
#endif |
393 |
d = &(*p)[6 + 6 - DATAHDR]; |
394 |
|
395 |
/* this overwrites part of the src mac, but we fix that later */ |
396 |
EVP_DecryptUpdate (cctx, |
397 |
d, &outl2, |
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(unsigned char *)&data, len - data_hdr_size ()); |
399 |
outl += outl2; |
400 |
|
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EVP_DecryptFinal_ex (cctx, (unsigned char *)d + outl, &outl2); |
402 |
outl += outl2; |
403 |
|
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seqno = ntohl (*(u32 *)(d + RAND_SIZE)); |
405 |
|
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id2mac (dst () ? dst() : THISNODE->id, p->dst); |
407 |
id2mac (src (), p->src); |
408 |
|
409 |
#if ENABLE_COMPRESSION |
410 |
if (type == PT_DATA_COMPRESSED) |
411 |
{ |
412 |
u32 cl = (d[DATAHDR] << 8) | d[DATAHDR + 1]; |
413 |
|
414 |
p->len = lzf_decompress (d + DATAHDR + 2, cl < MAX_MTU ? cl : 0, |
415 |
&(*p)[6 + 6], MAX_MTU) |
416 |
+ 6 + 6; |
417 |
} |
418 |
else |
419 |
p->len = outl + (6 + 6 - DATAHDR); |
420 |
#endif |
421 |
|
422 |
return p; |
423 |
} |
424 |
|
425 |
struct ping_packet : vpn_packet |
426 |
{ |
427 |
void setup (int dst, ptype type) |
428 |
{ |
429 |
set_hdr (type, dst); |
430 |
len = sizeof (*this) - sizeof (net_packet); |
431 |
} |
432 |
}; |
433 |
|
434 |
struct config_packet : vpn_packet |
435 |
{ |
436 |
// actually, hmaclen cannot be checked because the hmac |
437 |
// field comes before this data, so peers with other |
438 |
// hmacs simply will not work. |
439 |
u8 prot_major, prot_minor, randsize, hmaclen; |
440 |
u8 flags, challengelen, pad2, pad3; |
441 |
u32 cipher_nid, digest_nid, hmac_nid; |
442 |
|
443 |
const u8 curflags () const |
444 |
{ |
445 |
return 0x80 |
446 |
| (ENABLE_COMPRESSION ? 0x01 : 0x00); |
447 |
} |
448 |
|
449 |
void setup (ptype type, int dst); |
450 |
bool chk_config () const; |
451 |
}; |
452 |
|
453 |
void config_packet::setup (ptype type, int dst) |
454 |
{ |
455 |
prot_major = PROTOCOL_MAJOR; |
456 |
prot_minor = PROTOCOL_MINOR; |
457 |
randsize = RAND_SIZE; |
458 |
hmaclen = HMACLENGTH; |
459 |
flags = curflags (); |
460 |
challengelen = sizeof (rsachallenge); |
461 |
|
462 |
cipher_nid = htonl (EVP_CIPHER_nid (CIPHER)); |
463 |
digest_nid = htonl (EVP_MD_type (RSA_HASH)); |
464 |
hmac_nid = htonl (EVP_MD_type (DIGEST)); |
465 |
|
466 |
len = sizeof (*this) - sizeof (net_packet); |
467 |
set_hdr (type, dst); |
468 |
} |
469 |
|
470 |
bool config_packet::chk_config () const |
471 |
{ |
472 |
return prot_major == PROTOCOL_MAJOR |
473 |
&& randsize == RAND_SIZE |
474 |
&& hmaclen == HMACLENGTH |
475 |
&& flags == curflags () |
476 |
&& challengelen == sizeof (rsachallenge) |
477 |
&& cipher_nid == htonl (EVP_CIPHER_nid (CIPHER)) |
478 |
&& digest_nid == htonl (EVP_MD_type (RSA_HASH)) |
479 |
&& hmac_nid == htonl (EVP_MD_type (DIGEST)); |
480 |
} |
481 |
|
482 |
struct auth_req_packet : config_packet |
483 |
{ |
484 |
char magic[8]; |
485 |
u8 initiate; // false if this is just an automatic reply |
486 |
u8 protocols; // supported protocols (will get patches on forward) |
487 |
u8 pad2, pad3; |
488 |
rsaid id; |
489 |
rsaencrdata encr; |
490 |
|
491 |
auth_req_packet (int dst, bool initiate_, u8 protocols_) |
492 |
{ |
493 |
config_packet::setup (PT_AUTH_REQ, dst); |
494 |
strncpy (magic, MAGIC, 8); |
495 |
initiate = !!initiate_; |
496 |
protocols = protocols_; |
497 |
|
498 |
len = sizeof (*this) - sizeof (net_packet); |
499 |
} |
500 |
}; |
501 |
|
502 |
struct auth_res_packet : config_packet |
503 |
{ |
504 |
rsaid id; |
505 |
u8 pad1, pad2, pad3; |
506 |
u8 response_len; // encrypted length |
507 |
rsaresponse response; |
508 |
|
509 |
auth_res_packet (int dst) |
510 |
{ |
511 |
config_packet::setup (PT_AUTH_RES, dst); |
512 |
|
513 |
len = sizeof (*this) - sizeof (net_packet); |
514 |
} |
515 |
}; |
516 |
|
517 |
struct connect_req_packet : vpn_packet |
518 |
{ |
519 |
u8 id, protocols; |
520 |
u8 pad1, pad2; |
521 |
|
522 |
connect_req_packet (int dst, int id_, u8 protocols_) |
523 |
: id(id_) |
524 |
, protocols(protocols_) |
525 |
{ |
526 |
set_hdr (PT_CONNECT_REQ, dst); |
527 |
len = sizeof (*this) - sizeof (net_packet); |
528 |
} |
529 |
}; |
530 |
|
531 |
struct connect_info_packet : vpn_packet |
532 |
{ |
533 |
u8 id, protocols; |
534 |
u8 pad1, pad2; |
535 |
sockinfo si; |
536 |
|
537 |
connect_info_packet (int dst, int id_, const sockinfo &si_, u8 protocols_) |
538 |
: id(id_) |
539 |
, protocols(protocols_) |
540 |
, si(si_) |
541 |
{ |
542 |
set_hdr (PT_CONNECT_INFO, dst); |
543 |
|
544 |
len = sizeof (*this) - sizeof (net_packet); |
545 |
} |
546 |
}; |
547 |
|
548 |
///////////////////////////////////////////////////////////////////////////// |
549 |
|
550 |
void |
551 |
connection::reset_dstaddr () |
552 |
{ |
553 |
protocol = best_protocol (THISNODE->protocols & conf->protocols); |
554 |
|
555 |
// mask out protocols we cannot establish |
556 |
if (!conf->udp_port) protocol &= ~PROT_UDPv4; |
557 |
if (!conf->tcp_port) protocol &= ~PROT_TCPv4; |
558 |
|
559 |
si.set (conf, protocol); |
560 |
} |
561 |
|
562 |
void |
563 |
connection::send_ping (const sockinfo &si, u8 pong) |
564 |
{ |
565 |
ping_packet *pkt = new ping_packet; |
566 |
|
567 |
pkt->setup (conf->id, pong ? ping_packet::PT_PONG : ping_packet::PT_PING); |
568 |
vpn->send_vpn_packet (pkt, si, IPTOS_LOWDELAY); |
569 |
|
570 |
delete pkt; |
571 |
} |
572 |
|
573 |
void |
574 |
connection::send_reset (const sockinfo &si) |
575 |
{ |
576 |
if (reset_rate_limiter.can (si) && connectmode != conf_node::C_DISABLED) |
577 |
{ |
578 |
config_packet *pkt = new config_packet; |
579 |
|
580 |
pkt->setup (vpn_packet::PT_RESET, conf->id); |
581 |
vpn->send_vpn_packet (pkt, si, IPTOS_MINCOST); |
582 |
|
583 |
delete pkt; |
584 |
} |
585 |
} |
586 |
|
587 |
void |
588 |
connection::send_auth_request (const sockinfo &si, bool initiate) |
589 |
{ |
590 |
auth_req_packet *pkt = new auth_req_packet (conf->id, initiate, THISNODE->protocols); |
591 |
|
592 |
rsachallenge chg; |
593 |
|
594 |
rsa_cache.gen (pkt->id, chg); |
595 |
|
596 |
if (0 > RSA_public_encrypt (sizeof chg, |
597 |
(unsigned char *)&chg, (unsigned char *)&pkt->encr, |
598 |
conf->rsa_key, RSA_PKCS1_OAEP_PADDING)) |
599 |
fatal ("RSA_public_encrypt error"); |
600 |
|
601 |
slog (L_TRACE, ">>%d PT_AUTH_REQ [%s]", conf->id, (const char *)si); |
602 |
|
603 |
vpn->send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly |
604 |
|
605 |
delete pkt; |
606 |
} |
607 |
|
608 |
void |
609 |
connection::send_auth_response (const sockinfo &si, const rsaid &id, const rsachallenge &chg) |
610 |
{ |
611 |
auth_res_packet *pkt = new auth_res_packet (conf->id); |
612 |
|
613 |
pkt->id = id; |
614 |
|
615 |
rsa_hash (id, chg, pkt->response); |
616 |
|
617 |
pkt->hmac_set (octx); |
618 |
|
619 |
slog (L_TRACE, ">>%d PT_AUTH_RES [%s]", conf->id, (const char *)si); |
620 |
|
621 |
vpn->send_vpn_packet (pkt, si, IPTOS_RELIABILITY); // rsa is very very costly |
622 |
|
623 |
delete pkt; |
624 |
} |
625 |
|
626 |
void |
627 |
connection::send_connect_info (int rid, const sockinfo &rsi, u8 rprotocols) |
628 |
{ |
629 |
slog (L_TRACE, ">>%d PT_CONNECT_INFO(%d,%s)\n", |
630 |
conf->id, rid, (const char *)rsi); |
631 |
|
632 |
connect_info_packet *r = new connect_info_packet (conf->id, rid, rsi, rprotocols); |
633 |
|
634 |
r->hmac_set (octx); |
635 |
vpn->send_vpn_packet (r, si); |
636 |
|
637 |
delete r; |
638 |
} |
639 |
|
640 |
void |
641 |
connection::establish_connection_cb (time_watcher &w) |
642 |
{ |
643 |
if (ictx || conf == THISNODE |
644 |
|| connectmode == conf_node::C_NEVER |
645 |
|| connectmode == conf_node::C_DISABLED) |
646 |
w.at = TSTAMP_CANCEL; |
647 |
else if (w.at <= NOW) |
648 |
{ |
649 |
double retry_int = double (retry_cnt & 3 ? (retry_cnt & 3) : 1 << (retry_cnt >> 2)) * 0.6; |
650 |
|
651 |
if (retry_int < 3600 * 8) |
652 |
retry_cnt++; |
653 |
|
654 |
w.at = NOW + retry_int; |
655 |
|
656 |
if (conf->hostname) |
657 |
{ |
658 |
reset_dstaddr (); |
659 |
|
660 |
if (si.valid () && auth_rate_limiter.can (si)) |
661 |
{ |
662 |
if (retry_cnt < 4) |
663 |
send_auth_request (si, true); |
664 |
else |
665 |
send_ping (si, 0); |
666 |
} |
667 |
} |
668 |
else |
669 |
vpn->connect_request (conf->id); |
670 |
} |
671 |
} |
672 |
|
673 |
void |
674 |
connection::reset_connection () |
675 |
{ |
676 |
if (ictx && octx) |
677 |
{ |
678 |
slog (L_INFO, _("%s(%s): connection lost"), |
679 |
conf->nodename, (const char *)si); |
680 |
|
681 |
if (::conf.script_node_down) |
682 |
run_script (run_script_cb (this, &connection::script_node_down), false); |
683 |
} |
684 |
|
685 |
delete ictx; ictx = 0; |
686 |
delete octx; octx = 0; |
687 |
|
688 |
si.host= 0; |
689 |
|
690 |
last_activity = 0; |
691 |
retry_cnt = 0; |
692 |
|
693 |
rekey.reset (); |
694 |
keepalive.reset (); |
695 |
establish_connection.reset (); |
696 |
} |
697 |
|
698 |
void |
699 |
connection::shutdown () |
700 |
{ |
701 |
if (ictx && octx) |
702 |
send_reset (si); |
703 |
|
704 |
reset_connection (); |
705 |
} |
706 |
|
707 |
void |
708 |
connection::rekey_cb (time_watcher &w) |
709 |
{ |
710 |
w.at = TSTAMP_CANCEL; |
711 |
|
712 |
reset_connection (); |
713 |
establish_connection (); |
714 |
} |
715 |
|
716 |
void |
717 |
connection::send_data_packet (tap_packet *pkt, bool broadcast) |
718 |
{ |
719 |
vpndata_packet *p = new vpndata_packet; |
720 |
int tos = 0; |
721 |
|
722 |
if (conf->inherit_tos |
723 |
&& (*pkt)[12] == 0x08 && (*pkt)[13] == 0x00 // IP |
724 |
&& ((*pkt)[14] & 0xf0) == 0x40) // IPv4 |
725 |
tos = (*pkt)[15] & IPTOS_TOS_MASK; |
726 |
|
727 |
p->setup (this, broadcast ? 0 : conf->id, &((*pkt)[6 + 6]), pkt->len - 6 - 6, ++oseqno); // skip 2 macs |
728 |
vpn->send_vpn_packet (p, si, tos); |
729 |
|
730 |
delete p; |
731 |
|
732 |
if (oseqno > MAX_SEQNO) |
733 |
rekey (); |
734 |
} |
735 |
|
736 |
void |
737 |
connection::inject_data_packet (tap_packet *pkt, bool broadcast) |
738 |
{ |
739 |
if (ictx && octx) |
740 |
send_data_packet (pkt, broadcast); |
741 |
else |
742 |
{ |
743 |
if (!broadcast)//DDDD |
744 |
queue.put (new tap_packet (*pkt)); |
745 |
|
746 |
establish_connection (); |
747 |
} |
748 |
} |
749 |
|
750 |
void |
751 |
connection::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi) |
752 |
{ |
753 |
last_activity = NOW; |
754 |
|
755 |
slog (L_NOISE, "<<%d received packet type %d from %d to %d", |
756 |
conf->id, pkt->typ (), pkt->src (), pkt->dst ()); |
757 |
|
758 |
switch (pkt->typ ()) |
759 |
{ |
760 |
case vpn_packet::PT_PING: |
761 |
// we send pings instead of auth packets after some retries, |
762 |
// so reset the retry counter and establish a connection |
763 |
// when we receive a ping. |
764 |
if (!ictx) |
765 |
{ |
766 |
if (auth_rate_limiter.can (rsi)) |
767 |
send_auth_request (rsi, true); |
768 |
} |
769 |
else |
770 |
send_ping (rsi, 1); // pong |
771 |
|
772 |
break; |
773 |
|
774 |
case vpn_packet::PT_PONG: |
775 |
break; |
776 |
|
777 |
case vpn_packet::PT_RESET: |
778 |
{ |
779 |
reset_connection (); |
780 |
|
781 |
config_packet *p = (config_packet *) pkt; |
782 |
|
783 |
if (!p->chk_config ()) |
784 |
{ |
785 |
slog (L_WARN, _("%s(%s): protocol mismatch, disabling node"), |
786 |
conf->nodename, (const char *)rsi); |
787 |
connectmode = conf_node::C_DISABLED; |
788 |
} |
789 |
else if (connectmode == conf_node::C_ALWAYS) |
790 |
establish_connection (); |
791 |
} |
792 |
break; |
793 |
|
794 |
case vpn_packet::PT_AUTH_REQ: |
795 |
if (auth_rate_limiter.can (rsi)) |
796 |
{ |
797 |
auth_req_packet *p = (auth_req_packet *) pkt; |
798 |
|
799 |
slog (L_TRACE, "<<%d PT_AUTH_REQ(%d)", conf->id, p->initiate); |
800 |
|
801 |
if (p->chk_config () && !strncmp (p->magic, MAGIC, 8)) |
802 |
{ |
803 |
if (p->prot_minor != PROTOCOL_MINOR) |
804 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
805 |
conf->nodename, (const char *)rsi, |
806 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
807 |
|
808 |
if (p->initiate) |
809 |
send_auth_request (rsi, false); |
810 |
|
811 |
rsachallenge k; |
812 |
|
813 |
if (0 > RSA_private_decrypt (sizeof (p->encr), |
814 |
(unsigned char *)&p->encr, (unsigned char *)&k, |
815 |
::conf.rsa_key, RSA_PKCS1_OAEP_PADDING)) |
816 |
slog (L_ERR, _("%s(%s): challenge illegal or corrupted"), |
817 |
conf->nodename, (const char *)rsi); |
818 |
else |
819 |
{ |
820 |
retry_cnt = 0; |
821 |
establish_connection.start (NOW + 8); //? ;) |
822 |
keepalive.reset (); |
823 |
rekey.reset (); |
824 |
|
825 |
delete ictx; |
826 |
ictx = 0; |
827 |
|
828 |
delete octx; |
829 |
|
830 |
octx = new crypto_ctx (k, 1); |
831 |
oseqno = ntohl (*(u32 *)&k[CHG_SEQNO]) & 0x7fffffff; |
832 |
|
833 |
conf->protocols = p->protocols; |
834 |
send_auth_response (rsi, p->id, k); |
835 |
|
836 |
break; |
837 |
} |
838 |
} |
839 |
|
840 |
send_reset (rsi); |
841 |
} |
842 |
|
843 |
break; |
844 |
|
845 |
case vpn_packet::PT_AUTH_RES: |
846 |
{ |
847 |
auth_res_packet *p = (auth_res_packet *) pkt; |
848 |
|
849 |
slog (L_TRACE, "<<%d PT_AUTH_RES", conf->id); |
850 |
|
851 |
if (p->chk_config ()) |
852 |
{ |
853 |
if (p->prot_minor != PROTOCOL_MINOR) |
854 |
slog (L_INFO, _("%s(%s): protocol minor version mismatch: ours is %d, %s's is %d."), |
855 |
conf->nodename, (const char *)rsi, |
856 |
PROTOCOL_MINOR, conf->nodename, p->prot_minor); |
857 |
|
858 |
rsachallenge chg; |
859 |
|
860 |
if (!rsa_cache.find (p->id, chg)) |
861 |
slog (L_ERR, _("%s(%s): unrequested auth response"), |
862 |
conf->nodename, (const char *)rsi); |
863 |
else |
864 |
{ |
865 |
crypto_ctx *cctx = new crypto_ctx (chg, 0); |
866 |
|
867 |
if (!p->hmac_chk (cctx)) |
868 |
slog (L_ERR, _("%s(%s): hmac authentication error on auth response, received invalid packet\n" |
869 |
"could be an attack, or just corruption or an synchronization error"), |
870 |
conf->nodename, (const char *)rsi); |
871 |
else |
872 |
{ |
873 |
rsaresponse h; |
874 |
|
875 |
rsa_hash (p->id, chg, h); |
876 |
|
877 |
if (!memcmp ((u8 *)&h, (u8 *)p->response, sizeof h)) |
878 |
{ |
879 |
prot_minor = p->prot_minor; |
880 |
|
881 |
delete ictx; ictx = cctx; |
882 |
|
883 |
iseqno.reset (ntohl (*(u32 *)&chg[CHG_SEQNO]) & 0x7fffffff); // at least 2**31 sequence numbers are valid |
884 |
|
885 |
si = rsi; |
886 |
protocol = rsi.prot; |
887 |
|
888 |
rekey.start (NOW + ::conf.rekey); |
889 |
keepalive.start (NOW + ::conf.keepalive); |
890 |
|
891 |
// send queued packets |
892 |
while (tap_packet *p = queue.get ()) |
893 |
{ |
894 |
send_data_packet (p); |
895 |
delete p; |
896 |
} |
897 |
|
898 |
connectmode = conf->connectmode; |
899 |
|
900 |
slog (L_INFO, _("%s(%s): connection established, protocol version %d.%d"), |
901 |
conf->nodename, (const char *)rsi, |
902 |
p->prot_major, p->prot_minor); |
903 |
|
904 |
if (::conf.script_node_up) |
905 |
run_script (run_script_cb (this, &connection::script_node_up), false); |
906 |
|
907 |
break; |
908 |
} |
909 |
else |
910 |
slog (L_ERR, _("%s(%s): sent and received challenge do not match"), |
911 |
conf->nodename, (const char *)rsi); |
912 |
} |
913 |
|
914 |
delete cctx; |
915 |
} |
916 |
} |
917 |
} |
918 |
|
919 |
send_reset (rsi); |
920 |
break; |
921 |
|
922 |
case vpn_packet::PT_DATA_COMPRESSED: |
923 |
#if !ENABLE_COMPRESSION |
924 |
send_reset (rsi); |
925 |
break; |
926 |
#endif |
927 |
|
928 |
case vpn_packet::PT_DATA_UNCOMPRESSED: |
929 |
|
930 |
if (ictx && octx) |
931 |
{ |
932 |
vpndata_packet *p = (vpndata_packet *)pkt; |
933 |
|
934 |
if (rsi == si) |
935 |
{ |
936 |
if (!p->hmac_chk (ictx)) |
937 |
slog (L_ERR, _("%s(%s): hmac authentication error, 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 |
u32 seqno; |
943 |
tap_packet *d = p->unpack (this, seqno); |
944 |
|
945 |
if (iseqno.recv_ok (seqno)) |
946 |
{ |
947 |
vpn->tap->send (d); |
948 |
|
949 |
if (p->dst () == 0) // re-broadcast |
950 |
for (vpn::conns_vector::iterator i = vpn->conns.begin (); i != vpn->conns.end (); ++i) |
951 |
{ |
952 |
connection *c = *i; |
953 |
|
954 |
if (c->conf != THISNODE && c->conf != conf) |
955 |
c->inject_data_packet (d); |
956 |
} |
957 |
|
958 |
delete d; |
959 |
|
960 |
break; |
961 |
} |
962 |
} |
963 |
} |
964 |
else |
965 |
slog (L_ERR, _("received data packet from unknown source %s"), (const char *)rsi); |
966 |
} |
967 |
|
968 |
send_reset (rsi); |
969 |
break; |
970 |
|
971 |
case vpn_packet::PT_CONNECT_REQ: |
972 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
973 |
{ |
974 |
connect_req_packet *p = (connect_req_packet *) pkt; |
975 |
|
976 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
977 |
connection *c = vpn->conns[p->id - 1]; |
978 |
conf->protocols = p->protocols; |
979 |
|
980 |
slog (L_TRACE, "<<%d PT_CONNECT_REQ(%d) [%d]\n", |
981 |
conf->id, p->id, c->ictx && c->octx); |
982 |
|
983 |
if (c->ictx && c->octx) |
984 |
{ |
985 |
// send connect_info packets to both sides, in case one is |
986 |
// behind a nat firewall (or both ;) |
987 |
c->send_connect_info (conf->id, si, conf->protocols); |
988 |
send_connect_info (c->conf->id, c->si, c->conf->protocols); |
989 |
} |
990 |
} |
991 |
|
992 |
break; |
993 |
|
994 |
case vpn_packet::PT_CONNECT_INFO: |
995 |
if (ictx && octx && rsi == si && pkt->hmac_chk (ictx)) |
996 |
{ |
997 |
connect_info_packet *p = (connect_info_packet *) pkt; |
998 |
|
999 |
assert (p->id > 0 && p->id <= vpn->conns.size ()); // hmac-auth does not mean we accept anything |
1000 |
|
1001 |
connection *c = vpn->conns[p->id - 1]; |
1002 |
|
1003 |
c->conf->protocols = p->protocols; |
1004 |
protocol = best_protocol (c->conf->protocols & THISNODE->protocols & p->si.supported_protocols (c->conf)); |
1005 |
p->si.upgrade_protocol (protocol, c->conf); |
1006 |
|
1007 |
slog (L_TRACE, "<<%d PT_CONNECT_INFO(%d,%s) (%d)", |
1008 |
conf->id, p->id, (const char *)p->si, !c->ictx && !c->octx); |
1009 |
//slog (L_ERR, "%d PROTOCL(C%x,T%x,0S%x,S%x,P%x,SP%x)", |
1010 |
// p->id, c->conf->protocols, THISNODE->protocols, p->si.supported_protocols(0), p->si.supported_protocols (c->conf), |
1011 |
// protocol, p->si.prot); |
1012 |
|
1013 |
c->send_auth_request (p->si, true); |
1014 |
} |
1015 |
|
1016 |
break; |
1017 |
|
1018 |
default: |
1019 |
send_reset (rsi); |
1020 |
break; |
1021 |
} |
1022 |
} |
1023 |
|
1024 |
void connection::keepalive_cb (time_watcher &w) |
1025 |
{ |
1026 |
if (NOW >= last_activity + ::conf.keepalive + 30) |
1027 |
{ |
1028 |
reset_connection (); |
1029 |
establish_connection (); |
1030 |
} |
1031 |
else if (NOW < last_activity + ::conf.keepalive) |
1032 |
w.at = last_activity + ::conf.keepalive; |
1033 |
else if (conf->connectmode != conf_node::C_ONDEMAND |
1034 |
|| THISNODE->connectmode != conf_node::C_ONDEMAND) |
1035 |
{ |
1036 |
send_ping (si); |
1037 |
w.at = NOW + 5; |
1038 |
} |
1039 |
else |
1040 |
reset_connection (); |
1041 |
} |
1042 |
|
1043 |
void connection::connect_request (int id) |
1044 |
{ |
1045 |
connect_req_packet *p = new connect_req_packet (conf->id, id, conf->protocols); |
1046 |
|
1047 |
slog (L_TRACE, ">>%d PT_CONNECT_REQ(%d)", conf->id, id); |
1048 |
p->hmac_set (octx); |
1049 |
vpn->send_vpn_packet (p, si); |
1050 |
|
1051 |
delete p; |
1052 |
} |
1053 |
|
1054 |
void connection::script_node () |
1055 |
{ |
1056 |
vpn->script_if_up (); |
1057 |
|
1058 |
char *env; |
1059 |
asprintf (&env, "DESTID=%d", conf->id); putenv (env); |
1060 |
asprintf (&env, "DESTNODE=%s", conf->nodename); putenv (env); |
1061 |
asprintf (&env, "DESTIP=%s", si.ntoa ()); putenv (env); |
1062 |
asprintf (&env, "DESTPORT=%d", ntohs (si.port)); putenv (env); |
1063 |
} |
1064 |
|
1065 |
const char *connection::script_node_up () |
1066 |
{ |
1067 |
script_node (); |
1068 |
|
1069 |
putenv ("STATE=up"); |
1070 |
|
1071 |
return ::conf.script_node_up ? ::conf.script_node_up : "node-up"; |
1072 |
} |
1073 |
|
1074 |
const char *connection::script_node_down () |
1075 |
{ |
1076 |
script_node (); |
1077 |
|
1078 |
putenv ("STATE=down"); |
1079 |
|
1080 |
return ::conf.script_node_up ? ::conf.script_node_down : "node-down"; |
1081 |
} |
1082 |
|
1083 |
connection::connection(struct vpn *vpn_) |
1084 |
: vpn(vpn_) |
1085 |
, rekey (this, &connection::rekey_cb) |
1086 |
, keepalive (this, &connection::keepalive_cb) |
1087 |
, establish_connection (this, &connection::establish_connection_cb) |
1088 |
{ |
1089 |
octx = ictx = 0; |
1090 |
retry_cnt = 0; |
1091 |
|
1092 |
connectmode = conf_node::C_ALWAYS; // initial setting |
1093 |
reset_connection (); |
1094 |
} |
1095 |
|
1096 |
connection::~connection () |
1097 |
{ |
1098 |
shutdown (); |
1099 |
} |
1100 |
|
1101 |
void connection_init () |
1102 |
{ |
1103 |
auth_rate_limiter.clear (); |
1104 |
reset_rate_limiter.clear (); |
1105 |
} |
1106 |
|