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 | |
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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" |
… | |
… | |
559 | vector<dns_rcv *> rcvpq; |
570 | vector<dns_rcv *> rcvpq; |
560 | |
571 | |
561 | byte_stream rcvdq; int rcvseq; int repseq; |
572 | byte_stream rcvdq; int rcvseq; int repseq; |
562 | byte_stream snddq; int sndseq; |
573 | byte_stream snddq; int sndseq; |
563 | |
574 | |
564 | void time_cb (time_watcher &w); time_watcher tw; |
575 | inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
565 | void receive_rep (dns_rcv *r); |
576 | void receive_rep (dns_rcv *r); |
566 | |
577 | |
567 | dns_connection (connection *c); |
578 | dns_connection (connection *c); |
568 | ~dns_connection (); |
579 | ~dns_connection (); |
569 | }; |
580 | }; |
… | |
… | |
588 | : dns (dns) |
599 | : dns (dns) |
589 | { |
600 | { |
590 | timeout = 0; |
601 | timeout = 0; |
591 | retry = 0; |
602 | retry = 0; |
592 | seqno = 0; |
603 | seqno = 0; |
593 | sent = NOW; |
604 | sent = ev_now (); |
594 | stdhdr = false; |
605 | stdhdr = false; |
595 | |
606 | |
596 | pkt = new dns_packet; |
607 | pkt = new dns_packet; |
597 | |
608 | |
598 | pkt->id = next_id (); |
609 | pkt->id = next_id (); |
… | |
… | |
629 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
640 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
630 | { |
641 | { |
631 | stdhdr = true; |
642 | stdhdr = true; |
632 | this->seqno = seqno; |
643 | this->seqno = seqno; |
633 | |
644 | |
634 | timeout = NOW + INITIAL_TIMEOUT; |
645 | timeout = ev_now () + INITIAL_TIMEOUT; |
635 | |
646 | |
636 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
647 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
637 | pkt->qdcount = htons (1); |
648 | pkt->qdcount = htons (1); |
638 | |
649 | |
639 | int offs = 6*2; |
650 | int offs = 6*2; |
… | |
… | |
674 | pkt->len = offs; |
685 | pkt->len = offs; |
675 | } |
686 | } |
676 | |
687 | |
677 | void dns_snd::gen_syn_req () |
688 | void dns_snd::gen_syn_req () |
678 | { |
689 | { |
679 | timeout = NOW + INITIAL_SYN_TIMEOUT; |
690 | timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
680 | |
691 | |
681 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
692 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
682 | pkt->qdcount = htons (1); |
693 | pkt->qdcount = htons (1); |
683 | |
694 | |
684 | int offs = 6 * 2; |
695 | int offs = 6 * 2; |
… | |
… | |
724 | |
735 | |
725 | dns_connection::dns_connection (connection *c) |
736 | dns_connection::dns_connection (connection *c) |
726 | : c (c) |
737 | : c (c) |
727 | , rcvdq (MAX_BACKLOG * 2) |
738 | , rcvdq (MAX_BACKLOG * 2) |
728 | , snddq (MAX_BACKLOG) |
739 | , snddq (MAX_BACKLOG) |
729 | , tw (this, &dns_connection::time_cb) |
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|
730 | { |
740 | { |
|
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741 | tw.set<dns_connection, &dns_connection::time_cb> (this); |
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742 | |
731 | vpn = c->vpn; |
743 | vpn = c->vpn; |
732 | |
744 | |
733 | established = false; |
745 | established = false; |
734 | |
746 | |
735 | rcvseq = repseq = sndseq = 0; |
747 | rcvseq = repseq = sndseq = 0; |
… | |
… | |
750 | |
762 | |
751 | void dns_connection::receive_rep (dns_rcv *r) |
763 | void dns_connection::receive_rep (dns_rcv *r) |
752 | { |
764 | { |
753 | if (r->datalen) |
765 | if (r->datalen) |
754 | { |
766 | { |
755 | last_received = NOW; |
767 | last_received = ev_now (); |
756 | tw.trigger (); |
768 | tw (); |
757 | |
769 | |
758 | poll_interval = send_interval; |
770 | poll_interval = send_interval; |
759 | } |
771 | } |
760 | else |
772 | else |
761 | { |
773 | { |
… | |
… | |
1032 | #if 0 |
1044 | #if 0 |
1033 | dns->send_interval *= 0.999; |
1045 | dns->send_interval *= 0.999; |
1034 | #endif |
1046 | #endif |
1035 | // the latency surely puts an upper bound on |
1047 | // the latency surely puts an upper bound on |
1036 | // the minimum send interval |
1048 | // the minimum send interval |
1037 | double latency = NOW - (*i)->sent; |
1049 | double latency = ev_now () - (*i)->sent; |
1038 | |
1050 | |
1039 | if (latency < dns->min_latency) |
1051 | if (latency < dns->min_latency) |
1040 | dns->min_latency = latency; |
1052 | dns->min_latency = latency; |
1041 | |
1053 | |
1042 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
1054 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
… | |
… | |
1156 | break; |
1168 | break; |
1157 | } |
1169 | } |
1158 | } |
1170 | } |
1159 | |
1171 | |
1160 | void |
1172 | void |
1161 | vpn::dnsv4_ev (io_watcher &w, short revents) |
1173 | vpn::dnsv4_ev (ev::io &w, int revents) |
1162 | { |
1174 | { |
1163 | if (revents & EVENT_READ) |
1175 | if (revents & EV_READ) |
1164 | { |
1176 | { |
1165 | dns_packet *pkt = new dns_packet; |
1177 | dns_packet *pkt = new dns_packet; |
1166 | struct sockaddr_in sa; |
1178 | struct sockaddr_in sa; |
1167 | socklen_t sa_len = sizeof (sa); |
1179 | socklen_t sa_len = sizeof (sa); |
1168 | |
1180 | |
… | |
… | |
1194 | |
1206 | |
1195 | if (!c->dns) |
1207 | if (!c->dns) |
1196 | c->dns = new dns_connection (c); |
1208 | c->dns = new dns_connection (c); |
1197 | |
1209 | |
1198 | if (c->dns->snddq.put (pkt)) |
1210 | if (c->dns->snddq.put (pkt)) |
1199 | c->dns->tw.trigger (); |
1211 | c->dns->tw (); |
1200 | |
1212 | |
1201 | // always return true even if the buffer overflows |
1213 | // always return true even if the buffer overflows |
1202 | return true; |
1214 | return true; |
1203 | } |
1215 | } |
1204 | |
1216 | |
… | |
… | |
1209 | } |
1221 | } |
1210 | |
1222 | |
1211 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1223 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1212 | |
1224 | |
1213 | void |
1225 | void |
1214 | dns_connection::time_cb (time_watcher &w) |
1226 | dns_connection::time_cb (ev::timer &w, int revents) |
1215 | { |
1227 | { |
1216 | // servers have to be polled |
1228 | // servers have to be polled |
1217 | if (THISNODE->dns_port) |
1229 | if (THISNODE->dns_port) |
1218 | return; |
1230 | return; |
1219 | |
1231 | |
1220 | // check for timeouts and (re)transmit |
1232 | // check for timeouts and (re)transmit |
1221 | tstamp next = NOW + poll_interval; |
1233 | tstamp next = ev::now () + poll_interval; |
1222 | dns_snd *send = 0; |
1234 | dns_snd *send = 0; |
1223 | |
1235 | |
1224 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1236 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1225 | i != vpn->dns_sndpq.end (); |
1237 | i != vpn->dns_sndpq.end (); |
1226 | ++i) |
1238 | ++i) |
1227 | { |
1239 | { |
1228 | dns_snd *r = *i; |
1240 | dns_snd *r = *i; |
1229 | |
1241 | |
1230 | if (r->timeout <= NOW) |
1242 | if (r->timeout <= ev_now ()) |
1231 | { |
1243 | { |
1232 | if (!send) |
1244 | if (!send) |
1233 | { |
1245 | { |
1234 | send = r; |
1246 | send = r; |
1235 | |
1247 | |
1236 | r->retry++; |
1248 | r->retry++; |
1237 | r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor); |
1249 | r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); |
1238 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - NOW);//D |
1250 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
1239 | |
1251 | |
1240 | // the following code changes the query section a bit, forcing |
1252 | // the following code changes the query section a bit, forcing |
1241 | // the forwarder to generate a new request |
1253 | // the forwarder to generate a new request |
1242 | if (r->stdhdr) |
1254 | if (r->stdhdr) |
1243 | 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); |
… | |
… | |
1262 | } |
1274 | } |
1263 | } |
1275 | } |
1264 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1276 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1265 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1277 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1266 | { |
1278 | { |
1267 | if (last_sent + send_interval <= NOW) |
1279 | if (last_sent + send_interval <= ev_now ()) |
1268 | { |
1280 | { |
1269 | //printf ("sending data request etc.\n"); //D |
1281 | //printf ("sending data request etc.\n"); //D |
1270 | if (!snddq.empty () || last_received + 1. > NOW) |
1282 | if (!snddq.empty () || last_received + 1. > ev_now ()) |
1271 | { |
1283 | { |
1272 | poll_interval = send_interval; |
1284 | poll_interval = send_interval; |
1273 | NEXT (NOW + send_interval); |
1285 | NEXT (ev_now () + send_interval); |
1274 | } |
1286 | } |
1275 | |
1287 | |
1276 | send = new dns_snd (this); |
1288 | send = new dns_snd (this); |
1277 | send->gen_stream_req (sndseq, snddq); |
1289 | send->gen_stream_req (sndseq, snddq); |
1278 | send->timeout = NOW + min_latency * conf.dns_timeout_factor; |
1290 | send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
1279 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - NOW, min_latency, conf.dns_timeout_factor);//D |
1291 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
1280 | |
1292 | |
1281 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1293 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1282 | } |
1294 | } |
1283 | else |
1295 | else |
1284 | NEXT (last_sent + send_interval); |
1296 | NEXT (last_sent + send_interval); |
… | |
… | |
1288 | vpn->dns_sndpq.push_back (send); |
1300 | vpn->dns_sndpq.push_back (send); |
1289 | } |
1301 | } |
1290 | |
1302 | |
1291 | if (send) |
1303 | if (send) |
1292 | { |
1304 | { |
1293 | last_sent = NOW; |
1305 | last_sent = ev_now (); |
1294 | sendto (vpn->dnsv4_fd, |
1306 | sendto (vpn->dnsv4_fd, |
1295 | send->pkt->at (0), send->pkt->len, 0, |
1307 | send->pkt->at (0), send->pkt->len, 0, |
1296 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1308 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1297 | } |
1309 | } |
1298 | |
1310 | |
1299 | 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)", |
1300 | poll_interval, send_interval, next - NOW, |
1312 | poll_interval, send_interval, next - ev_now (), |
1301 | vpn->dns_sndpq.size (), snddq.size (), |
1313 | vpn->dns_sndpq.size (), snddq.size (), |
1302 | rcvpq.size ()); |
1314 | rcvpq.size ()); |
1303 | |
1315 | |
1304 | // 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 |
1305 | // doesn't seem to happen anymore |
1317 | // doesn't seem to happen anymore |
1306 | if (next < NOW + 0.001) |
1318 | if (next < ev_now () + 0.001) |
1307 | next = NOW + 0.1; |
1319 | next = ev_now () + 0.1; |
1308 | |
1320 | |
1309 | w.start (next); |
1321 | w.start (next - ev_now ()); |
1310 | } |
1322 | } |
1311 | |
1323 | |
1312 | #endif |
1324 | #endif |
1313 | |
1325 | |