| 1 | /* |
1 | /* |
| 2 | vpn_dns.C -- handle the dns tunnel part of the protocol. |
2 | vpn_dns.C -- handle the dns tunnel part of the protocol. |
| 3 | Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de> |
3 | Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de> |
| 4 | |
4 | |
| 5 | This file is part of GVPE. |
5 | This file is part of GVPE. |
| 6 | |
6 | |
| 7 | GVPE is free software; you can redistribute it and/or modify |
7 | GVPE is free software; you can redistribute it and/or modify it |
| 8 | it under the terms of the GNU General Public License as published by |
8 | under the terms of the GNU General Public License as published by the |
| 9 | the Free Software Foundation; either version 2 of the License, or |
9 | Free Software Foundation; either version 3 of the License, or (at your |
| 10 | (at your option) any later version. |
10 | option) any later version. |
| 11 | |
11 | |
| 12 | This program is distributed in the hope that it will be useful, |
12 | This program is distributed in the hope that it will be useful, but |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General |
| 15 | GNU General Public License for more details. |
15 | Public License for more details. |
| 16 | |
16 | |
| 17 | You should have received a copy of the GNU General Public License |
17 | You should have received a copy of the GNU General Public License along |
| 18 | along with gvpe; if not, write to the Free Software |
18 | with this program; if not, see <http://www.gnu.org/licenses/>. |
| 19 | Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
19 | |
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20 | Additional permission under GNU GPL version 3 section 7 |
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21 | |
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22 | If you modify this Program, or any covered work, by linking or |
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23 | combining it with the OpenSSL project's OpenSSL library (or a modified |
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24 | version of that library), containing parts covered by the terms of the |
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25 | OpenSSL or SSLeay licenses, the licensors of this Program grant you |
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26 | additional permission to convey the resulting work. Corresponding |
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27 | Source for a non-source form of such a combination shall include the |
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28 | source code for the parts of OpenSSL used as well as that of the |
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29 | covered work. |
| 20 | */ |
30 | */ |
| 21 | |
31 | |
| 22 | // TODO: EDNS0 option to increase dns mtu? |
32 | // TODO: EDNS0 option to increase dns mtu? |
| 23 | // TODO: re-write dns packet parsing/creation using a safe mem-buffer |
33 | // TODO: re-write dns packet parsing/creation using a safe mem-buffer |
| 24 | // to ensure no buffer overflows or similar problems. |
34 | // to ensure no buffer overflows or similar problems. |
| … | |
… | |
| 42 | #include <unistd.h> |
52 | #include <unistd.h> |
| 43 | #include <fcntl.h> |
53 | #include <fcntl.h> |
| 44 | |
54 | |
| 45 | #include <map> |
55 | #include <map> |
| 46 | |
56 | |
|
|
57 | #include <cstdio> /* bug in libgmp: gmp.h relies on cstdio being included */ |
| 47 | #include <gmp.h> |
58 | #include <gmp.h> |
| 48 | |
59 | |
| 49 | #include "netcompat.h" |
60 | #include "netcompat.h" |
| 50 | |
61 | |
| 51 | #include "vpn.h" |
62 | #include "vpn.h" |
| … | |
… | |
| 461 | r4 = r5 = r6 = r7 = 0; |
472 | r4 = r5 = r6 = r7 = 0; |
| 462 | } |
473 | } |
| 463 | |
474 | |
| 464 | bool dns_cfg::valid () |
475 | bool dns_cfg::valid () |
| 465 | { |
476 | { |
|
|
477 | // although the protocol itself allows for some configurability, |
|
|
478 | // only the following encoding/decoding settings are implemented. |
| 466 | return id1 == 'G' |
479 | return id1 == 'G' |
| 467 | && id2 == 'V' |
480 | && id2 == 'V' |
| 468 | && id3 == 'P' |
481 | && id3 == 'P' |
| 469 | && id4 == 'E' |
482 | && id4 == 'E' |
| 470 | && seq_cdc == 26 |
483 | && seq_cdc == 26 |
| … | |
… | |
| 557 | vector<dns_rcv *> rcvpq; |
570 | vector<dns_rcv *> rcvpq; |
| 558 | |
571 | |
| 559 | byte_stream rcvdq; int rcvseq; int repseq; |
572 | byte_stream rcvdq; int rcvseq; int repseq; |
| 560 | byte_stream snddq; int sndseq; |
573 | byte_stream snddq; int sndseq; |
| 561 | |
574 | |
| 562 | void time_cb (time_watcher &w); time_watcher tw; |
575 | inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
| 563 | void receive_rep (dns_rcv *r); |
576 | void receive_rep (dns_rcv *r); |
| 564 | |
577 | |
| 565 | dns_connection (connection *c); |
578 | dns_connection (connection *c); |
| 566 | ~dns_connection (); |
579 | ~dns_connection (); |
| 567 | }; |
580 | }; |
| … | |
… | |
| 586 | : dns (dns) |
599 | : dns (dns) |
| 587 | { |
600 | { |
| 588 | timeout = 0; |
601 | timeout = 0; |
| 589 | retry = 0; |
602 | retry = 0; |
| 590 | seqno = 0; |
603 | seqno = 0; |
| 591 | sent = NOW; |
604 | sent = ev_now (); |
| 592 | stdhdr = false; |
605 | stdhdr = false; |
| 593 | |
606 | |
| 594 | pkt = new dns_packet; |
607 | pkt = new dns_packet; |
| 595 | |
608 | |
| 596 | pkt->id = next_id (); |
609 | pkt->id = next_id (); |
| … | |
… | |
| 627 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
640 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
| 628 | { |
641 | { |
| 629 | stdhdr = true; |
642 | stdhdr = true; |
| 630 | this->seqno = seqno; |
643 | this->seqno = seqno; |
| 631 | |
644 | |
| 632 | timeout = NOW + INITIAL_TIMEOUT; |
645 | timeout = ev_now () + INITIAL_TIMEOUT; |
| 633 | |
646 | |
| 634 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
647 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
| 635 | pkt->qdcount = htons (1); |
648 | pkt->qdcount = htons (1); |
| 636 | |
649 | |
| 637 | int offs = 6*2; |
650 | int offs = 6*2; |
| … | |
… | |
| 672 | pkt->len = offs; |
685 | pkt->len = offs; |
| 673 | } |
686 | } |
| 674 | |
687 | |
| 675 | void dns_snd::gen_syn_req () |
688 | void dns_snd::gen_syn_req () |
| 676 | { |
689 | { |
| 677 | timeout = NOW + INITIAL_SYN_TIMEOUT; |
690 | timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
| 678 | |
691 | |
| 679 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
692 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
| 680 | pkt->qdcount = htons (1); |
693 | pkt->qdcount = htons (1); |
| 681 | |
694 | |
| 682 | int offs = 6 * 2; |
695 | int offs = 6 * 2; |
| … | |
… | |
| 722 | |
735 | |
| 723 | dns_connection::dns_connection (connection *c) |
736 | dns_connection::dns_connection (connection *c) |
| 724 | : c (c) |
737 | : c (c) |
| 725 | , rcvdq (MAX_BACKLOG * 2) |
738 | , rcvdq (MAX_BACKLOG * 2) |
| 726 | , snddq (MAX_BACKLOG) |
739 | , snddq (MAX_BACKLOG) |
| 727 | , tw (this, &dns_connection::time_cb) |
|
|
| 728 | { |
740 | { |
|
|
741 | tw.set<dns_connection, &dns_connection::time_cb> (this); |
|
|
742 | |
| 729 | vpn = c->vpn; |
743 | vpn = c->vpn; |
| 730 | |
744 | |
| 731 | established = false; |
745 | established = false; |
| 732 | |
746 | |
| 733 | rcvseq = repseq = sndseq = 0; |
747 | rcvseq = repseq = sndseq = 0; |
| … | |
… | |
| 748 | |
762 | |
| 749 | void dns_connection::receive_rep (dns_rcv *r) |
763 | void dns_connection::receive_rep (dns_rcv *r) |
| 750 | { |
764 | { |
| 751 | if (r->datalen) |
765 | if (r->datalen) |
| 752 | { |
766 | { |
| 753 | last_received = NOW; |
767 | last_received = ev_now (); |
| 754 | tw.trigger (); |
768 | tw (); |
| 755 | |
769 | |
| 756 | poll_interval = send_interval; |
770 | poll_interval = send_interval; |
| 757 | } |
771 | } |
| 758 | else |
772 | else |
| 759 | { |
773 | { |
| … | |
… | |
| 769 | |
783 | |
| 770 | // find next packet |
784 | // find next packet |
| 771 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
785 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
| 772 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
786 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
| 773 | { |
787 | { |
|
|
788 | //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D |
| 774 | // enter the packet into our input stream |
789 | // enter the packet into our input stream |
| 775 | r = *i; |
790 | r = *i; |
| 776 | |
791 | |
| 777 | // remove the oldest packet, look forward, as it's oldest first |
792 | // remove the oldest packet, look forward, as it's oldest first |
| 778 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
793 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
| 779 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
794 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
| 780 | { |
795 | { |
|
|
796 | //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D |
| 781 | delete *j; |
797 | delete *j; |
| 782 | rcvpq.erase (j); |
798 | rcvpq.erase (j); |
| 783 | break; |
799 | break; |
| 784 | } |
800 | } |
| 785 | |
801 | |
| … | |
… | |
| 1013 | { |
1029 | { |
| 1014 | dns_connection *dns = (*i)->dns; |
1030 | dns_connection *dns = (*i)->dns; |
| 1015 | connection *c = dns->c; |
1031 | connection *c = dns->c; |
| 1016 | int seqno = (*i)->seqno; |
1032 | int seqno = (*i)->seqno; |
| 1017 | u8 data[MAXSIZE], *datap = data; |
1033 | u8 data[MAXSIZE], *datap = data; |
|
|
1034 | //printf ("rcv pkt %x\n", seqno);//D |
| 1018 | |
1035 | |
| 1019 | if ((*i)->retry) |
1036 | if ((*i)->retry) |
| 1020 | { |
1037 | { |
| 1021 | dns->send_interval *= 1.01; |
1038 | dns->send_interval *= 1.01; |
| 1022 | if (dns->send_interval > MAX_SEND_INTERVAL) |
1039 | if (dns->send_interval > MAX_SEND_INTERVAL) |
| … | |
… | |
| 1027 | #if 0 |
1044 | #if 0 |
| 1028 | dns->send_interval *= 0.999; |
1045 | dns->send_interval *= 0.999; |
| 1029 | #endif |
1046 | #endif |
| 1030 | // the latency surely puts an upper bound on |
1047 | // the latency surely puts an upper bound on |
| 1031 | // the minimum send interval |
1048 | // the minimum send interval |
| 1032 | double latency = NOW - (*i)->sent; |
1049 | double latency = ev_now () - (*i)->sent; |
| 1033 | |
1050 | |
| 1034 | if (latency < dns->min_latency) |
1051 | if (latency < dns->min_latency) |
| 1035 | dns->min_latency = latency; |
1052 | dns->min_latency = latency; |
| 1036 | |
1053 | |
| 1037 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
1054 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
| … | |
… | |
| 1151 | break; |
1168 | break; |
| 1152 | } |
1169 | } |
| 1153 | } |
1170 | } |
| 1154 | |
1171 | |
| 1155 | void |
1172 | void |
| 1156 | vpn::dnsv4_ev (io_watcher &w, short revents) |
1173 | vpn::dnsv4_ev (ev::io &w, int revents) |
| 1157 | { |
1174 | { |
| 1158 | if (revents & EVENT_READ) |
1175 | if (revents & EV_READ) |
| 1159 | { |
1176 | { |
| 1160 | dns_packet *pkt = new dns_packet; |
1177 | dns_packet *pkt = new dns_packet; |
| 1161 | struct sockaddr_in sa; |
1178 | struct sockaddr_in sa; |
| 1162 | socklen_t sa_len = sizeof (sa); |
1179 | socklen_t sa_len = sizeof (sa); |
| 1163 | |
1180 | |
| … | |
… | |
| 1189 | |
1206 | |
| 1190 | if (!c->dns) |
1207 | if (!c->dns) |
| 1191 | c->dns = new dns_connection (c); |
1208 | c->dns = new dns_connection (c); |
| 1192 | |
1209 | |
| 1193 | if (c->dns->snddq.put (pkt)) |
1210 | if (c->dns->snddq.put (pkt)) |
| 1194 | c->dns->tw.trigger (); |
1211 | c->dns->tw (); |
| 1195 | |
1212 | |
| 1196 | // always return true even if the buffer overflows |
1213 | // always return true even if the buffer overflows |
| 1197 | return true; |
1214 | return true; |
| 1198 | } |
1215 | } |
| 1199 | |
1216 | |
| … | |
… | |
| 1204 | } |
1221 | } |
| 1205 | |
1222 | |
| 1206 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1223 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
| 1207 | |
1224 | |
| 1208 | void |
1225 | void |
| 1209 | dns_connection::time_cb (time_watcher &w) |
1226 | dns_connection::time_cb (ev::timer &w, int revents) |
| 1210 | { |
1227 | { |
| 1211 | // servers have to be polled |
1228 | // servers have to be polled |
| 1212 | if (THISNODE->dns_port) |
1229 | if (THISNODE->dns_port) |
| 1213 | return; |
1230 | return; |
| 1214 | |
1231 | |
| 1215 | // check for timeouts and (re)transmit |
1232 | // check for timeouts and (re)transmit |
| 1216 | tstamp next = NOW + poll_interval; |
1233 | tstamp next = ev::now () + poll_interval; |
| 1217 | dns_snd *send = 0; |
1234 | dns_snd *send = 0; |
| 1218 | |
1235 | |
| 1219 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1236 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
| 1220 | i != vpn->dns_sndpq.end (); |
1237 | i != vpn->dns_sndpq.end (); |
| 1221 | ++i) |
1238 | ++i) |
| 1222 | { |
1239 | { |
| 1223 | dns_snd *r = *i; |
1240 | dns_snd *r = *i; |
| 1224 | |
1241 | |
| 1225 | if (r->timeout <= NOW) |
1242 | if (r->timeout <= ev_now ()) |
| 1226 | { |
1243 | { |
| 1227 | if (!send) |
1244 | if (!send) |
| 1228 | { |
1245 | { |
| 1229 | send = r; |
1246 | send = r; |
| 1230 | |
1247 | |
| 1231 | r->retry++; |
1248 | r->retry++; |
| 1232 | r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor); |
1249 | r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); |
|
|
1250 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
| 1233 | |
1251 | |
| 1234 | // the following code changes the query section a bit, forcing |
1252 | // the following code changes the query section a bit, forcing |
| 1235 | // the forwarder to generate a new request |
1253 | // the forwarder to generate a new request |
| 1236 | if (r->stdhdr) |
1254 | if (r->stdhdr) |
| 1237 | { |
|
|
| 1238 | //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry); |
|
|
| 1239 | //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
1255 | encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
| 1240 | } |
|
|
| 1241 | } |
1256 | } |
| 1242 | } |
1257 | } |
| 1243 | else |
1258 | else |
| 1244 | NEXT (r->timeout); |
1259 | NEXT (r->timeout); |
| 1245 | } |
1260 | } |
| … | |
… | |
| 1259 | } |
1274 | } |
| 1260 | } |
1275 | } |
| 1261 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1276 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
| 1262 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1277 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
| 1263 | { |
1278 | { |
| 1264 | if (last_sent + send_interval <= NOW) |
1279 | if (last_sent + send_interval <= ev_now ()) |
| 1265 | { |
1280 | { |
| 1266 | //printf ("sending data request etc.\n"); //D |
1281 | //printf ("sending data request etc.\n"); //D |
| 1267 | if (!snddq.empty () || last_received + 1. > NOW) |
1282 | if (!snddq.empty () || last_received + 1. > ev_now ()) |
| 1268 | { |
1283 | { |
| 1269 | poll_interval = send_interval; |
1284 | poll_interval = send_interval; |
| 1270 | NEXT (NOW + send_interval); |
1285 | NEXT (ev_now () + send_interval); |
| 1271 | } |
1286 | } |
| 1272 | |
1287 | |
| 1273 | send = new dns_snd (this); |
1288 | send = new dns_snd (this); |
| 1274 | send->gen_stream_req (sndseq, snddq); |
1289 | send->gen_stream_req (sndseq, snddq); |
| 1275 | send->timeout = NOW + min_latency * conf.dns_timeout_factor; |
1290 | send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
|
|
1291 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
| 1276 | |
1292 | |
| 1277 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1293 | sndseq = (sndseq + 1) & SEQNO_MASK; |
| 1278 | } |
1294 | } |
| 1279 | else |
1295 | else |
| 1280 | NEXT (last_sent + send_interval); |
1296 | NEXT (last_sent + send_interval); |
| … | |
… | |
| 1284 | vpn->dns_sndpq.push_back (send); |
1300 | vpn->dns_sndpq.push_back (send); |
| 1285 | } |
1301 | } |
| 1286 | |
1302 | |
| 1287 | if (send) |
1303 | if (send) |
| 1288 | { |
1304 | { |
| 1289 | last_sent = NOW; |
1305 | last_sent = ev_now (); |
| 1290 | sendto (vpn->dnsv4_fd, |
1306 | sendto (vpn->dnsv4_fd, |
| 1291 | send->pkt->at (0), send->pkt->len, 0, |
1307 | send->pkt->at (0), send->pkt->len, 0, |
| 1292 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1308 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
| 1293 | } |
1309 | } |
| 1294 | |
1310 | |
| 1295 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
1311 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
| 1296 | poll_interval, send_interval, next - NOW, |
1312 | poll_interval, send_interval, next - ev_now (), |
| 1297 | vpn->dns_sndpq.size (), snddq.size (), |
1313 | vpn->dns_sndpq.size (), snddq.size (), |
| 1298 | rcvpq.size ()); |
1314 | rcvpq.size ()); |
| 1299 | |
1315 | |
| 1300 | // TODO: no idea when this happens, but when next < NOW, we have a problem |
1316 | // TODO: no idea when this happens, but when next < ev_now (), we have a problem |
| 1301 | // doesn't seem to happen anymore |
1317 | // doesn't seem to happen anymore |
| 1302 | if (next < NOW + 0.001) |
1318 | if (next < ev_now () + 0.001) |
| 1303 | next = NOW + 0.1; |
1319 | next = ev_now () + 0.1; |
| 1304 | |
1320 | |
| 1305 | w.start (next); |
1321 | w.start (next - ev_now ()); |
| 1306 | } |
1322 | } |
| 1307 | |
1323 | |
| 1308 | #endif |
1324 | #endif |
| 1309 | |
1325 | |
