| 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" |
| … | |
… | |
| 72 | #define MAX_PKT_SIZE 512 |
83 | #define MAX_PKT_SIZE 512 |
| 73 | |
84 | |
| 74 | #define RR_TYPE_A 1 |
85 | #define RR_TYPE_A 1 |
| 75 | #define RR_TYPE_NULL 10 |
86 | #define RR_TYPE_NULL 10 |
| 76 | #define RR_TYPE_TXT 16 |
87 | #define RR_TYPE_TXT 16 |
|
|
88 | #define RR_TYPE_AAAA 28 |
| 77 | #define RR_TYPE_ANY 255 |
89 | #define RR_TYPE_ANY 255 |
| 78 | |
90 | |
| 79 | #define RR_CLASS_IN 1 |
91 | #define RR_CLASS_IN 1 |
| 80 | |
92 | |
| 81 | #define CMD_IP_1 207 |
93 | #define CMD_IP_1 207 |
| … | |
… | |
| 559 | vector<dns_rcv *> rcvpq; |
571 | vector<dns_rcv *> rcvpq; |
| 560 | |
572 | |
| 561 | byte_stream rcvdq; int rcvseq; int repseq; |
573 | byte_stream rcvdq; int rcvseq; int repseq; |
| 562 | byte_stream snddq; int sndseq; |
574 | byte_stream snddq; int sndseq; |
| 563 | |
575 | |
| 564 | void time_cb (time_watcher &w); time_watcher tw; |
576 | inline void time_cb (ev::timer &w, int revents); ev::timer tw; |
| 565 | void receive_rep (dns_rcv *r); |
577 | void receive_rep (dns_rcv *r); |
| 566 | |
578 | |
| 567 | dns_connection (connection *c); |
579 | dns_connection (connection *c); |
| 568 | ~dns_connection (); |
580 | ~dns_connection (); |
| 569 | }; |
581 | }; |
| … | |
… | |
| 588 | : dns (dns) |
600 | : dns (dns) |
| 589 | { |
601 | { |
| 590 | timeout = 0; |
602 | timeout = 0; |
| 591 | retry = 0; |
603 | retry = 0; |
| 592 | seqno = 0; |
604 | seqno = 0; |
| 593 | sent = NOW; |
605 | sent = ev_now (); |
| 594 | stdhdr = false; |
606 | stdhdr = false; |
| 595 | |
607 | |
| 596 | pkt = new dns_packet; |
608 | pkt = new dns_packet; |
| 597 | |
609 | |
| 598 | pkt->id = next_id (); |
610 | pkt->id = next_id (); |
| … | |
… | |
| 629 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
641 | void dns_snd::gen_stream_req (int seqno, byte_stream &stream) |
| 630 | { |
642 | { |
| 631 | stdhdr = true; |
643 | stdhdr = true; |
| 632 | this->seqno = seqno; |
644 | this->seqno = seqno; |
| 633 | |
645 | |
| 634 | timeout = NOW + INITIAL_TIMEOUT; |
646 | timeout = ev_now () + INITIAL_TIMEOUT; |
| 635 | |
647 | |
| 636 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
648 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
| 637 | pkt->qdcount = htons (1); |
649 | pkt->qdcount = htons (1); |
| 638 | |
650 | |
| 639 | int offs = 6*2; |
651 | int offs = 6*2; |
| … | |
… | |
| 674 | pkt->len = offs; |
686 | pkt->len = offs; |
| 675 | } |
687 | } |
| 676 | |
688 | |
| 677 | void dns_snd::gen_syn_req () |
689 | void dns_snd::gen_syn_req () |
| 678 | { |
690 | { |
| 679 | timeout = NOW + INITIAL_SYN_TIMEOUT; |
691 | timeout = ev_now () + INITIAL_SYN_TIMEOUT; |
| 680 | |
692 | |
| 681 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
693 | pkt->flags = htons (DEFAULT_CLIENT_FLAGS); |
| 682 | pkt->qdcount = htons (1); |
694 | pkt->qdcount = htons (1); |
| 683 | |
695 | |
| 684 | int offs = 6 * 2; |
696 | int offs = 6 * 2; |
| … | |
… | |
| 724 | |
736 | |
| 725 | dns_connection::dns_connection (connection *c) |
737 | dns_connection::dns_connection (connection *c) |
| 726 | : c (c) |
738 | : c (c) |
| 727 | , rcvdq (MAX_BACKLOG * 2) |
739 | , rcvdq (MAX_BACKLOG * 2) |
| 728 | , snddq (MAX_BACKLOG) |
740 | , snddq (MAX_BACKLOG) |
| 729 | , tw (this, &dns_connection::time_cb) |
|
|
| 730 | { |
741 | { |
|
|
742 | tw.set<dns_connection, &dns_connection::time_cb> (this); |
|
|
743 | |
| 731 | vpn = c->vpn; |
744 | vpn = c->vpn; |
| 732 | |
745 | |
| 733 | established = false; |
746 | established = false; |
| 734 | |
747 | |
| 735 | rcvseq = repseq = sndseq = 0; |
748 | rcvseq = repseq = sndseq = 0; |
| … | |
… | |
| 750 | |
763 | |
| 751 | void dns_connection::receive_rep (dns_rcv *r) |
764 | void dns_connection::receive_rep (dns_rcv *r) |
| 752 | { |
765 | { |
| 753 | if (r->datalen) |
766 | if (r->datalen) |
| 754 | { |
767 | { |
| 755 | last_received = NOW; |
768 | last_received = ev_now (); |
| 756 | tw.trigger (); |
769 | tw (); |
| 757 | |
770 | |
| 758 | poll_interval = send_interval; |
771 | poll_interval = send_interval; |
| 759 | } |
772 | } |
| 760 | else |
773 | else |
| 761 | { |
774 | { |
| … | |
… | |
| 771 | |
784 | |
| 772 | // find next packet |
785 | // find next packet |
| 773 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
786 | for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) |
| 774 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
787 | if (SEQNO_EQ (rcvseq, (*i)->seqno)) |
| 775 | { |
788 | { |
|
|
789 | //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D |
| 776 | // enter the packet into our input stream |
790 | // enter the packet into our input stream |
| 777 | r = *i; |
791 | r = *i; |
| 778 | |
792 | |
| 779 | // remove the oldest packet, look forward, as it's oldest first |
793 | // remove the oldest packet, look forward, as it's oldest first |
| 780 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
794 | for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) |
| 781 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
795 | if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) |
| 782 | { |
796 | { |
|
|
797 | //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D |
| 783 | delete *j; |
798 | delete *j; |
| 784 | rcvpq.erase (j); |
799 | rcvpq.erase (j); |
| 785 | break; |
800 | break; |
| 786 | } |
801 | } |
| 787 | |
802 | |
| … | |
… | |
| 1015 | { |
1030 | { |
| 1016 | dns_connection *dns = (*i)->dns; |
1031 | dns_connection *dns = (*i)->dns; |
| 1017 | connection *c = dns->c; |
1032 | connection *c = dns->c; |
| 1018 | int seqno = (*i)->seqno; |
1033 | int seqno = (*i)->seqno; |
| 1019 | u8 data[MAXSIZE], *datap = data; |
1034 | u8 data[MAXSIZE], *datap = data; |
|
|
1035 | //printf ("rcv pkt %x\n", seqno);//D |
| 1020 | |
1036 | |
| 1021 | if ((*i)->retry) |
1037 | if ((*i)->retry) |
| 1022 | { |
1038 | { |
| 1023 | dns->send_interval *= 1.01; |
1039 | dns->send_interval *= 1.01; |
| 1024 | if (dns->send_interval > MAX_SEND_INTERVAL) |
1040 | if (dns->send_interval > MAX_SEND_INTERVAL) |
| … | |
… | |
| 1029 | #if 0 |
1045 | #if 0 |
| 1030 | dns->send_interval *= 0.999; |
1046 | dns->send_interval *= 0.999; |
| 1031 | #endif |
1047 | #endif |
| 1032 | // the latency surely puts an upper bound on |
1048 | // the latency surely puts an upper bound on |
| 1033 | // the minimum send interval |
1049 | // the minimum send interval |
| 1034 | double latency = NOW - (*i)->sent; |
1050 | double latency = ev_now () - (*i)->sent; |
| 1035 | |
1051 | |
| 1036 | if (latency < dns->min_latency) |
1052 | if (latency < dns->min_latency) |
| 1037 | dns->min_latency = latency; |
1053 | dns->min_latency = latency; |
| 1038 | |
1054 | |
| 1039 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
1055 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
| … | |
… | |
| 1153 | break; |
1169 | break; |
| 1154 | } |
1170 | } |
| 1155 | } |
1171 | } |
| 1156 | |
1172 | |
| 1157 | void |
1173 | void |
| 1158 | vpn::dnsv4_ev (io_watcher &w, short revents) |
1174 | vpn::dnsv4_ev (ev::io &w, int revents) |
| 1159 | { |
1175 | { |
| 1160 | if (revents & EVENT_READ) |
1176 | if (revents & EV_READ) |
| 1161 | { |
1177 | { |
| 1162 | dns_packet *pkt = new dns_packet; |
1178 | dns_packet *pkt = new dns_packet; |
| 1163 | struct sockaddr_in sa; |
1179 | struct sockaddr_in sa; |
| 1164 | socklen_t sa_len = sizeof (sa); |
1180 | socklen_t sa_len = sizeof (sa); |
| 1165 | |
1181 | |
| … | |
… | |
| 1191 | |
1207 | |
| 1192 | if (!c->dns) |
1208 | if (!c->dns) |
| 1193 | c->dns = new dns_connection (c); |
1209 | c->dns = new dns_connection (c); |
| 1194 | |
1210 | |
| 1195 | if (c->dns->snddq.put (pkt)) |
1211 | if (c->dns->snddq.put (pkt)) |
| 1196 | c->dns->tw.trigger (); |
1212 | c->dns->tw (); |
| 1197 | |
1213 | |
| 1198 | // always return true even if the buffer overflows |
1214 | // always return true even if the buffer overflows |
| 1199 | return true; |
1215 | return true; |
| 1200 | } |
1216 | } |
| 1201 | |
1217 | |
| … | |
… | |
| 1206 | } |
1222 | } |
| 1207 | |
1223 | |
| 1208 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
1224 | #define NEXT(w) do { if (next > (w)) next = w; } while (0) |
| 1209 | |
1225 | |
| 1210 | void |
1226 | void |
| 1211 | dns_connection::time_cb (time_watcher &w) |
1227 | dns_connection::time_cb (ev::timer &w, int revents) |
| 1212 | { |
1228 | { |
| 1213 | // servers have to be polled |
1229 | // servers have to be polled |
| 1214 | if (THISNODE->dns_port) |
1230 | if (THISNODE->dns_port) |
| 1215 | return; |
1231 | return; |
| 1216 | |
1232 | |
| 1217 | // check for timeouts and (re)transmit |
1233 | // check for timeouts and (re)transmit |
| 1218 | tstamp next = NOW + poll_interval; |
1234 | tstamp next = ev::now () + poll_interval; |
| 1219 | dns_snd *send = 0; |
1235 | dns_snd *send = 0; |
| 1220 | |
1236 | |
| 1221 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
1237 | for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); |
| 1222 | i != vpn->dns_sndpq.end (); |
1238 | i != vpn->dns_sndpq.end (); |
| 1223 | ++i) |
1239 | ++i) |
| 1224 | { |
1240 | { |
| 1225 | dns_snd *r = *i; |
1241 | dns_snd *r = *i; |
| 1226 | |
1242 | |
| 1227 | if (r->timeout <= NOW) |
1243 | if (r->timeout <= ev_now ()) |
| 1228 | { |
1244 | { |
| 1229 | if (!send) |
1245 | if (!send) |
| 1230 | { |
1246 | { |
| 1231 | send = r; |
1247 | send = r; |
| 1232 | |
1248 | |
| 1233 | r->retry++; |
1249 | r->retry++; |
| 1234 | r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor); |
1250 | r->timeout = ev_now () + (r->retry * min_latency * conf.dns_timeout_factor); |
|
|
1251 | //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev_now ());//D |
| 1235 | |
1252 | |
| 1236 | // the following code changes the query section a bit, forcing |
1253 | // the following code changes the query section a bit, forcing |
| 1237 | // the forwarder to generate a new request |
1254 | // the forwarder to generate a new request |
| 1238 | if (r->stdhdr) |
1255 | if (r->stdhdr) |
| 1239 | { |
|
|
| 1240 | //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry); |
|
|
| 1241 | //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
1256 | encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); |
| 1242 | } |
|
|
| 1243 | } |
1257 | } |
| 1244 | } |
1258 | } |
| 1245 | else |
1259 | else |
| 1246 | NEXT (r->timeout); |
1260 | NEXT (r->timeout); |
| 1247 | } |
1261 | } |
| … | |
… | |
| 1261 | } |
1275 | } |
| 1262 | } |
1276 | } |
| 1263 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1277 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
| 1264 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1278 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
| 1265 | { |
1279 | { |
| 1266 | if (last_sent + send_interval <= NOW) |
1280 | if (last_sent + send_interval <= ev_now ()) |
| 1267 | { |
1281 | { |
| 1268 | //printf ("sending data request etc.\n"); //D |
1282 | //printf ("sending data request etc.\n"); //D |
| 1269 | if (!snddq.empty () || last_received + 1. > NOW) |
1283 | if (!snddq.empty () || last_received + 1. > ev_now ()) |
| 1270 | { |
1284 | { |
| 1271 | poll_interval = send_interval; |
1285 | poll_interval = send_interval; |
| 1272 | NEXT (NOW + send_interval); |
1286 | NEXT (ev_now () + send_interval); |
| 1273 | } |
1287 | } |
| 1274 | |
1288 | |
| 1275 | send = new dns_snd (this); |
1289 | send = new dns_snd (this); |
| 1276 | send->gen_stream_req (sndseq, snddq); |
1290 | send->gen_stream_req (sndseq, snddq); |
| 1277 | send->timeout = NOW + min_latency * conf.dns_timeout_factor; |
1291 | send->timeout = ev_now () + min_latency * conf.dns_timeout_factor; |
|
|
1292 | //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev_now (), min_latency, conf.dns_timeout_factor);//D |
| 1278 | |
1293 | |
| 1279 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1294 | sndseq = (sndseq + 1) & SEQNO_MASK; |
| 1280 | } |
1295 | } |
| 1281 | else |
1296 | else |
| 1282 | NEXT (last_sent + send_interval); |
1297 | NEXT (last_sent + send_interval); |
| … | |
… | |
| 1286 | vpn->dns_sndpq.push_back (send); |
1301 | vpn->dns_sndpq.push_back (send); |
| 1287 | } |
1302 | } |
| 1288 | |
1303 | |
| 1289 | if (send) |
1304 | if (send) |
| 1290 | { |
1305 | { |
| 1291 | last_sent = NOW; |
1306 | last_sent = ev_now (); |
| 1292 | sendto (vpn->dnsv4_fd, |
1307 | sendto (vpn->dnsv4_fd, |
| 1293 | send->pkt->at (0), send->pkt->len, 0, |
1308 | send->pkt->at (0), send->pkt->len, 0, |
| 1294 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
1309 | vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); |
| 1295 | } |
1310 | } |
| 1296 | |
1311 | |
| 1297 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
1312 | slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", |
| 1298 | poll_interval, send_interval, next - NOW, |
1313 | poll_interval, send_interval, next - ev_now (), |
| 1299 | vpn->dns_sndpq.size (), snddq.size (), |
1314 | vpn->dns_sndpq.size (), snddq.size (), |
| 1300 | rcvpq.size ()); |
1315 | rcvpq.size ()); |
| 1301 | |
1316 | |
| 1302 | // TODO: no idea when this happens, but when next < NOW, we have a problem |
1317 | // TODO: no idea when this happens, but when next < ev_now (), we have a problem |
| 1303 | // doesn't seem to happen anymore |
1318 | // doesn't seem to happen anymore |
| 1304 | if (next < NOW + 0.001) |
1319 | if (next < ev_now () + 0.001) |
| 1305 | next = NOW + 0.1; |
1320 | next = ev_now () + 0.1; |
| 1306 | |
1321 | |
| 1307 | w.start (next); |
1322 | w.start (next - ev_now ()); |
| 1308 | } |
1323 | } |
| 1309 | |
1324 | |
| 1310 | #endif |
1325 | #endif |
| 1311 | |
1326 | |
