… | |
… | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | GNU General Public License for more details. |
15 | GNU General 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 |
18 | along with gvpe; if not, write to the Free Software |
18 | along with gvpe; if not, write to the Free Software |
19 | Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
19 | Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
20 | */ |
20 | */ |
|
|
21 | |
|
|
22 | // TODO: EDNS0 option to increase dns mtu? |
|
|
23 | // TODO: re-write dns packet parsing/creation using a safe mem-buffer |
|
|
24 | // to ensure no buffer overflows or similar problems. |
21 | |
25 | |
22 | #include "config.h" |
26 | #include "config.h" |
23 | |
27 | |
24 | #if ENABLE_DNS |
28 | #if ENABLE_DNS |
25 | |
29 | |
… | |
… | |
44 | |
48 | |
45 | #include "netcompat.h" |
49 | #include "netcompat.h" |
46 | |
50 | |
47 | #include "vpn.h" |
51 | #include "vpn.h" |
48 | |
52 | |
49 | #define MIN_POLL_INTERVAL .02 // how often to poll minimally when the server has data |
|
|
50 | #define MAX_POLL_INTERVAL 6. // how often to poll minimally when the server has no data |
53 | #define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data |
51 | #define ACTIVITY_INTERVAL 5. |
54 | #define ACTIVITY_INTERVAL 5. |
52 | |
55 | |
53 | #define INITIAL_TIMEOUT 0.1 // retry timeouts |
56 | #define INITIAL_TIMEOUT 0.1 // retry timeouts |
54 | #define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn |
57 | #define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn |
55 | |
58 | |
56 | #define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests |
|
|
57 | #define MAX_SEND_INTERVAL 2. // optimistic? |
59 | #define MAX_SEND_INTERVAL 2. // optimistic? |
58 | |
60 | |
59 | #define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate |
|
|
60 | #define MAX_OUTSTANDING 100 // max. outstanding requests |
|
|
61 | #define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog |
61 | #define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog |
62 | #define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE |
62 | #define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE |
63 | |
63 | |
64 | #define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well |
64 | #define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well |
65 | // 240 leaves about 4 bytes of server reply data |
65 | // 240 leaves about 4 bytes of server reply data |
66 | // every two request bytes less give room for one reply byte |
66 | // every request byte less give room for two reply bytes |
67 | |
67 | |
68 | #define SEQNO_MASK 0x3fff |
68 | #define SEQNO_MASK 0x3fff |
69 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
69 | #define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) |
70 | |
70 | |
71 | #define MAX_LBL_SIZE 63 |
71 | #define MAX_LBL_SIZE 63 |
… | |
… | |
424 | u16 max_size; |
424 | u16 max_size; |
425 | u8 seq_cdc; |
425 | u8 seq_cdc; |
426 | u8 req_cdc; |
426 | u8 req_cdc; |
427 | |
427 | |
428 | u8 rep_cdc; |
428 | u8 rep_cdc; |
|
|
429 | u8 delay; // time in 0.01s units that the server may delay replying packets |
429 | u8 r2, r3, r4; |
430 | u8 r3, r4; |
430 | |
431 | |
431 | u8 r5, r6, r7, r8; |
432 | u8 r5, r6, r7, r8; |
432 | |
433 | |
433 | void reset (int clientid); |
434 | void reset (int clientid); |
434 | bool valid (); |
435 | bool valid (); |
… | |
… | |
452 | req_cdc = 62; |
453 | req_cdc = 62; |
453 | rep_cdc = 0; |
454 | rep_cdc = 0; |
454 | max_size = htons (MAX_PKT_SIZE); |
455 | max_size = htons (MAX_PKT_SIZE); |
455 | client = htons (clientid); |
456 | client = htons (clientid); |
456 | uid = next_uid++; |
457 | uid = next_uid++; |
|
|
458 | delay = 0; |
457 | |
459 | |
458 | r2 = r3 = r4 = 0; |
460 | r3 = r4 = 0; |
459 | r4 = r5 = r6 = r7 = 0; |
461 | r4 = r5 = r6 = r7 = 0; |
460 | } |
462 | } |
461 | |
463 | |
462 | bool dns_cfg::valid () |
464 | bool dns_cfg::valid () |
463 | { |
465 | { |
|
|
466 | // although the protocol itself allows for some configurability, |
|
|
467 | // only the following encoding/decoding settings are implemented. |
464 | return id1 == 'G' |
468 | return id1 == 'G' |
465 | && id2 == 'V' |
469 | && id2 == 'V' |
466 | && id3 == 'P' |
470 | && id3 == 'P' |
467 | && id4 == 'E' |
471 | && id4 == 'E' |
468 | && seq_cdc == 26 |
472 | && seq_cdc == 26 |
… | |
… | |
552 | double min_latency; |
556 | double min_latency; |
553 | double poll_interval, send_interval; |
557 | double poll_interval, send_interval; |
554 | |
558 | |
555 | vector<dns_rcv *> rcvpq; |
559 | vector<dns_rcv *> rcvpq; |
556 | |
560 | |
557 | byte_stream rcvdq; int rcvseq; |
561 | byte_stream rcvdq; int rcvseq; int repseq; |
558 | byte_stream snddq; int sndseq; |
562 | byte_stream snddq; int sndseq; |
559 | |
563 | |
560 | void time_cb (time_watcher &w); time_watcher tw; |
564 | void time_cb (time_watcher &w); time_watcher tw; |
561 | void receive_rep (dns_rcv *r); |
565 | void receive_rep (dns_rcv *r); |
562 | |
566 | |
… | |
… | |
719 | ///////////////////////////////////////////////////////////////////////////// |
723 | ///////////////////////////////////////////////////////////////////////////// |
720 | |
724 | |
721 | dns_connection::dns_connection (connection *c) |
725 | dns_connection::dns_connection (connection *c) |
722 | : c (c) |
726 | : c (c) |
723 | , rcvdq (MAX_BACKLOG * 2) |
727 | , rcvdq (MAX_BACKLOG * 2) |
724 | , snddq (MAX_BACKLOG * 2) |
728 | , snddq (MAX_BACKLOG) |
725 | , tw (this, &dns_connection::time_cb) |
729 | , tw (this, &dns_connection::time_cb) |
726 | { |
730 | { |
727 | vpn = c->vpn; |
731 | vpn = c->vpn; |
728 | |
732 | |
729 | established = false; |
733 | established = false; |
730 | |
734 | |
731 | rcvseq = sndseq = 0; |
735 | rcvseq = repseq = sndseq = 0; |
732 | |
736 | |
733 | last_sent = last_received = 0; |
737 | last_sent = last_received = 0; |
734 | poll_interval = MIN_POLL_INTERVAL; |
738 | poll_interval = 0.5; // starting here |
735 | send_interval = 0.5; // starting rate |
739 | send_interval = 0.5; // starting rate |
736 | min_latency = INITIAL_TIMEOUT; |
740 | min_latency = INITIAL_TIMEOUT; |
737 | } |
741 | } |
738 | |
742 | |
739 | dns_connection::~dns_connection () |
743 | dns_connection::~dns_connection () |
… | |
… | |
790 | } |
794 | } |
791 | |
795 | |
792 | while (vpn_packet *pkt = rcvdq.get ()) |
796 | while (vpn_packet *pkt = rcvdq.get ()) |
793 | { |
797 | { |
794 | sockinfo si; |
798 | sockinfo si; |
795 | si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; |
799 | si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4; |
796 | |
800 | |
797 | vpn->recv_vpn_packet (pkt, si); |
801 | vpn->recv_vpn_packet (pkt, si); |
798 | |
802 | |
799 | delete pkt; |
803 | delete pkt; |
800 | } |
804 | } |
… | |
… | |
854 | if (0 < client && client <= conns.size ()) |
858 | if (0 < client && client <= conns.size ()) |
855 | { |
859 | { |
856 | connection *c = conns [client - 1]; |
860 | connection *c = conns [client - 1]; |
857 | dns_connection *dns = c->dns; |
861 | dns_connection *dns = c->dns; |
858 | dns_rcv *rcv; |
862 | dns_rcv *rcv; |
859 | bool in_seq; |
|
|
860 | |
863 | |
861 | if (dns) |
864 | if (dns) |
862 | { |
865 | { |
863 | for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) |
866 | for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) |
864 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
867 | if (SEQNO_EQ ((*i)->seqno, seqno)) |
… | |
… | |
875 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
878 | memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); |
876 | |
879 | |
877 | goto duplicate_request; |
880 | goto duplicate_request; |
878 | } |
881 | } |
879 | |
882 | |
880 | in_seq = dns->rcvseq == seqno; |
|
|
881 | |
|
|
882 | // new packet, queue |
883 | // new packet, queue |
883 | rcv = new dns_rcv (seqno, data, datalen); |
884 | rcv = new dns_rcv (seqno, data, datalen); |
884 | dns->receive_rep (rcv); |
885 | dns->receive_rep (rcv); |
885 | } |
886 | } |
886 | |
887 | |
… | |
… | |
903 | dlen -= qlen; |
904 | dlen -= qlen; |
904 | |
905 | |
905 | // only put data into in-order sequence packets, if |
906 | // only put data into in-order sequence packets, if |
906 | // we receive out-of-order packets we generate empty |
907 | // we receive out-of-order packets we generate empty |
907 | // replies |
908 | // replies |
908 | while (dlen > 1 && !dns->snddq.empty () && in_seq) |
909 | //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D |
|
|
910 | if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW) |
909 | { |
911 | { |
|
|
912 | dns->repseq = seqno; |
|
|
913 | |
|
|
914 | while (dlen > 1 && !dns->snddq.empty ()) |
|
|
915 | { |
910 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
916 | int txtlen = dlen <= 255 ? dlen - 1 : 255; |
911 | |
917 | |
912 | if (txtlen > dns->snddq.size ()) |
918 | if (txtlen > dns->snddq.size ()) |
913 | txtlen = dns->snddq.size (); |
919 | txtlen = dns->snddq.size (); |
914 | |
920 | |
915 | pkt[offs++] = txtlen; |
921 | pkt[offs++] = txtlen; |
916 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
922 | memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); |
917 | offs += txtlen; |
923 | offs += txtlen; |
918 | dns->snddq.remove (txtlen); |
924 | dns->snddq.remove (txtlen); |
919 | |
925 | |
920 | dlen -= txtlen + 1; |
926 | dlen -= txtlen + 1; |
|
|
927 | } |
921 | } |
928 | } |
922 | |
929 | |
923 | // avoid empty TXT rdata |
930 | // avoid completely empty TXT rdata |
924 | if (offs == rdlen_offs) |
931 | if (offs == rdlen_offs) |
925 | pkt[offs++] = 0; |
932 | pkt[offs++] = 0; |
926 | |
933 | |
927 | slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); |
934 | slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); |
928 | } |
935 | } |
… | |
… | |
1027 | double latency = NOW - (*i)->sent; |
1034 | double latency = NOW - (*i)->sent; |
1028 | |
1035 | |
1029 | if (latency < dns->min_latency) |
1036 | if (latency < dns->min_latency) |
1030 | dns->min_latency = latency; |
1037 | dns->min_latency = latency; |
1031 | |
1038 | |
1032 | if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) |
1039 | if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor) |
1033 | dns->send_interval = dns->min_latency * LATENCY_FACTOR; |
1040 | dns->send_interval = dns->min_latency * conf.dns_overlap_factor; |
1034 | |
1041 | |
1035 | if (dns->send_interval < MIN_SEND_INTERVAL) |
1042 | if (dns->send_interval < conf.dns_send_interval) |
1036 | dns->send_interval = MIN_SEND_INTERVAL; |
1043 | dns->send_interval = conf.dns_send_interval; |
1037 | } |
1044 | } |
1038 | |
1045 | |
1039 | delete *i; |
1046 | delete *i; |
1040 | dns_sndpq.erase (i); |
1047 | dns_sndpq.erase (i); |
1041 | |
1048 | |
… | |
… | |
1174 | } |
1181 | } |
1175 | |
1182 | |
1176 | bool |
1183 | bool |
1177 | vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1184 | vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) |
1178 | { |
1185 | { |
1179 | int client = ntohs (si.port); |
1186 | int client = ntohl (si.host); |
1180 | |
1187 | |
1181 | assert (0 < client && client <= conns.size ()); |
1188 | assert (0 < client && client <= conns.size ()); |
1182 | |
1189 | |
1183 | connection *c = conns [client - 1]; |
1190 | connection *c = conns [client - 1]; |
1184 | |
1191 | |
1185 | if (!c->dns) |
1192 | if (!c->dns) |
1186 | c->dns = new dns_connection (c); |
1193 | c->dns = new dns_connection (c); |
1187 | |
1194 | |
1188 | if (!c->dns->snddq.put (pkt)) |
1195 | if (c->dns->snddq.put (pkt)) |
1189 | return false; |
|
|
1190 | |
|
|
1191 | c->dns->tw.trigger (); |
1196 | c->dns->tw.trigger (); |
1192 | |
1197 | |
|
|
1198 | // always return true even if the buffer overflows |
1193 | return true; |
1199 | return true; |
1194 | } |
1200 | } |
1195 | |
1201 | |
1196 | void |
1202 | void |
1197 | connection::dnsv4_reset_connection () |
1203 | connection::dnsv4_reset_connection () |
… | |
… | |
1223 | if (!send) |
1229 | if (!send) |
1224 | { |
1230 | { |
1225 | send = r; |
1231 | send = r; |
1226 | |
1232 | |
1227 | r->retry++; |
1233 | r->retry++; |
1228 | r->timeout = NOW + (r->retry * min_latency * 8.); |
1234 | r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor); |
1229 | |
1235 | |
1230 | // the following code changes the query section a bit, forcing |
1236 | // the following code changes the query section a bit, forcing |
1231 | // the forwarder to generate a new request |
1237 | // the forwarder to generate a new request |
1232 | if (r->stdhdr) |
1238 | if (r->stdhdr) |
1233 | { |
1239 | { |
… | |
… | |
1240 | NEXT (r->timeout); |
1246 | NEXT (r->timeout); |
1241 | } |
1247 | } |
1242 | |
1248 | |
1243 | if (!send) |
1249 | if (!send) |
1244 | { |
1250 | { |
1245 | if (last_sent + send_interval <= NOW) |
1251 | // generate a new packet, if wise |
|
|
1252 | |
|
|
1253 | if (!established) |
1246 | { |
1254 | { |
1247 | // generate a new packet, if wise |
1255 | if (vpn->dns_sndpq.empty ()) |
1248 | |
|
|
1249 | if (!established) |
|
|
1250 | { |
1256 | { |
1251 | if (vpn->dns_sndpq.empty ()) |
|
|
1252 | { |
|
|
1253 | send = new dns_snd (this); |
1257 | send = new dns_snd (this); |
1254 | |
1258 | |
1255 | cfg.reset (THISNODE->id); |
1259 | cfg.reset (THISNODE->id); |
1256 | send->gen_syn_req (); |
1260 | send->gen_syn_req (); |
1257 | } |
|
|
1258 | } |
1261 | } |
1259 | else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING |
1262 | } |
|
|
1263 | else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding |
1260 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
1264 | && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) |
|
|
1265 | { |
|
|
1266 | if (last_sent + send_interval <= NOW) |
1261 | { |
1267 | { |
1262 | //printf ("sending data request etc.\n"); //D |
1268 | //printf ("sending data request etc.\n"); //D |
1263 | if (!snddq.empty () || last_received + 1. > NOW) |
1269 | if (!snddq.empty () || last_received + 1. > NOW) |
1264 | { |
1270 | { |
1265 | poll_interval = send_interval; |
1271 | poll_interval = send_interval; |
1266 | NEXT (NOW + send_interval); |
1272 | NEXT (NOW + send_interval); |
1267 | } |
1273 | } |
1268 | |
1274 | |
1269 | send = new dns_snd (this); |
1275 | send = new dns_snd (this); |
1270 | send->gen_stream_req (sndseq, snddq); |
1276 | send->gen_stream_req (sndseq, snddq); |
1271 | send->timeout = NOW + min_latency * 8.; |
1277 | send->timeout = NOW + min_latency * conf.dns_timeout_factor; |
1272 | |
1278 | |
1273 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1279 | sndseq = (sndseq + 1) & SEQNO_MASK; |
1274 | } |
1280 | } |
1275 | |
1281 | else |
1276 | if (send) |
1282 | NEXT (last_sent + send_interval); |
1277 | vpn->dns_sndpq.push_back (send); |
|
|
1278 | } |
1283 | } |
1279 | else |
1284 | |
1280 | NEXT (last_sent + send_interval); |
1285 | if (send) |
|
|
1286 | vpn->dns_sndpq.push_back (send); |
1281 | } |
1287 | } |
1282 | |
1288 | |
1283 | if (send) |
1289 | if (send) |
1284 | { |
1290 | { |
1285 | last_sent = NOW; |
1291 | last_sent = NOW; |
… | |
… | |
1292 | poll_interval, send_interval, next - NOW, |
1298 | poll_interval, send_interval, next - NOW, |
1293 | vpn->dns_sndpq.size (), snddq.size (), |
1299 | vpn->dns_sndpq.size (), snddq.size (), |
1294 | rcvpq.size ()); |
1300 | rcvpq.size ()); |
1295 | |
1301 | |
1296 | // TODO: no idea when this happens, but when next < NOW, we have a problem |
1302 | // TODO: no idea when this happens, but when next < NOW, we have a problem |
|
|
1303 | // doesn't seem to happen anymore |
1297 | if (next < NOW + 0.0001) |
1304 | if (next < NOW + 0.001) |
1298 | next = NOW + 0.1; |
1305 | next = NOW + 0.1; |
1299 | |
1306 | |
1300 | w.start (next); |
1307 | w.start (next); |
1301 | } |
1308 | } |
1302 | |
1309 | |