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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.24 by pcg, Mon Mar 7 01:31:26 2005 UTC vs.
Revision 1.38 by pcg, Tue Apr 19 04:23:38 2005 UTC

… …
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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20*/ 20*/
21 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.
25
22#include "config.h" 26#include "config.h"
23 27
24#if ENABLE_DNS 28#if ENABLE_DNS
25 29
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 30// dns processing is EXTREMELY ugly. For obvious(?) reasons.
… …
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 0.5 // optimistic? 59#define MAX_SEND_INTERVAL 2. // optimistic?
58 60
59#define MAX_OUTSTANDING 10 // max. outstanding requests
60#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
61#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
62 63
63#define MAX_DOMAIN_SIZE 220 // 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
64// 240 leaves about 4 bytes of server reply data 65// 240 leaves about 4 bytes of server reply data
65// every two request bytes less give room for one reply byte 66// every request byte less give room for two reply bytes
66 67
67#define SEQNO_MASK 0x3fff 68#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
69 70
70#define MAX_LBL_SIZE 63 71#define MAX_LBL_SIZE 63
… …
423 u16 max_size; 424 u16 max_size;
424 u8 seq_cdc; 425 u8 seq_cdc;
425 u8 req_cdc; 426 u8 req_cdc;
426 427
427 u8 rep_cdc; 428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
428 u8 r2, r3, r4; 430 u8 r3, r4;
429 431
430 u8 r5, r6, r7, r8; 432 u8 r5, r6, r7, r8;
431 433
432 void reset (int clientid); 434 void reset (int clientid);
433 bool valid (); 435 bool valid ();
… …
448 flags = 0; 450 flags = 0;
449 def_ttl = 0; 451 def_ttl = 0;
450 seq_cdc = 26; 452 seq_cdc = 26;
451 req_cdc = 62; 453 req_cdc = 62;
452 rep_cdc = 0; 454 rep_cdc = 0;
453 max_size = ntohs (MAX_PKT_SIZE); 455 max_size = htons (MAX_PKT_SIZE);
454 client = ntohs (clientid); 456 client = htons (clientid);
455 uid = next_uid++; 457 uid = next_uid++;
458 delay = 0;
456 459
457 r2 = r3 = r4 = 0; 460 r3 = r4 = 0;
458 r4 = r5 = r6 = r7 = 0; 461 r4 = r5 = r6 = r7 = 0;
459} 462}
460 463
461bool dns_cfg::valid () 464bool dns_cfg::valid ()
462{ 465{
… …
465 && id3 == 'P' 468 && id3 == 'P'
466 && id4 == 'E' 469 && id4 == 'E'
467 && seq_cdc == 26 470 && seq_cdc == 26
468 && req_cdc == 62 471 && req_cdc == 62
469 && rep_cdc == 0 472 && rep_cdc == 0
470 && version == 1 473 && version == 1;
471 && max_size == ntohs (MAX_PKT_SIZE);
472} 474}
473 475
474struct dns_packet : net_packet 476struct dns_packet : net_packet
475{ 477{
476 u16 id; 478 u16 id;
… …
547 549
548 bool established; 550 bool established;
549 551
550 tstamp last_received; 552 tstamp last_received;
551 tstamp last_sent; 553 tstamp last_sent;
552 double last_latency; 554 double min_latency;
553 double poll_interval, send_interval; 555 double poll_interval, send_interval;
554 556
555 vector<dns_rcv *> rcvpq; 557 vector<dns_rcv *> rcvpq;
556 558
557 byte_stream rcvdq; int rcvseq; 559 byte_stream rcvdq; int rcvseq; int repseq;
558 byte_stream snddq; int sndseq; 560 byte_stream snddq; int sndseq;
559 561
560 void time_cb (time_watcher &w); time_watcher tw; 562 void time_cb (time_watcher &w); time_watcher tw;
561 void receive_rep (dns_rcv *r); 563 void receive_rep (dns_rcv *r);
562 564
… …
719///////////////////////////////////////////////////////////////////////////// 721/////////////////////////////////////////////////////////////////////////////
720 722
721dns_connection::dns_connection (connection *c) 723dns_connection::dns_connection (connection *c)
722: c (c) 724: c (c)
723, rcvdq (MAX_BACKLOG * 2) 725, rcvdq (MAX_BACKLOG * 2)
724, snddq (MAX_BACKLOG * 2) 726, snddq (MAX_BACKLOG)
725, tw (this, &dns_connection::time_cb) 727, tw (this, &dns_connection::time_cb)
726{ 728{
727 vpn = c->vpn; 729 vpn = c->vpn;
728 730
729 established = false; 731 established = false;
730 732
731 rcvseq = sndseq = 0; 733 rcvseq = repseq = sndseq = 0;
732 734
733 last_sent = last_received = 0; 735 last_sent = last_received = 0;
734 poll_interval = MIN_POLL_INTERVAL; 736 poll_interval = 0.5; // starting here
735 send_interval = 0.5; // starting rate 737 send_interval = 0.5; // starting rate
736 last_latency = INITIAL_TIMEOUT; 738 min_latency = INITIAL_TIMEOUT;
737} 739}
738 740
739dns_connection::~dns_connection () 741dns_connection::~dns_connection ()
740{ 742{
741 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 743 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
754 poll_interval = send_interval; 756 poll_interval = send_interval;
755 } 757 }
756 else 758 else
757 { 759 {
758 poll_interval *= 1.5; 760 poll_interval *= 1.5;
761
759 if (poll_interval > MAX_POLL_INTERVAL) 762 if (poll_interval > MAX_POLL_INTERVAL)
760 poll_interval = MAX_POLL_INTERVAL; 763 poll_interval = MAX_POLL_INTERVAL;
761 } 764 }
762 765
763 rcvpq.push_back (r); 766 rcvpq.push_back (r);
… …
789 } 792 }
790 793
791 while (vpn_packet *pkt = rcvdq.get ()) 794 while (vpn_packet *pkt = rcvdq.get ())
792 { 795 {
793 sockinfo si; 796 sockinfo si;
794 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 797 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
795 798
796 vpn->recv_vpn_packet (pkt, si); 799 vpn->recv_vpn_packet (pkt, si);
797 800
798 delete pkt; 801 delete pkt;
799 } 802 }
… …
853 if (0 < client && client <= conns.size ()) 856 if (0 < client && client <= conns.size ())
854 { 857 {
855 connection *c = conns [client - 1]; 858 connection *c = conns [client - 1];
856 dns_connection *dns = c->dns; 859 dns_connection *dns = c->dns;
857 dns_rcv *rcv; 860 dns_rcv *rcv;
858 bool in_seq;
859 861
860 if (dns) 862 if (dns)
861 { 863 {
862 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 864 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
863 if (SEQNO_EQ ((*i)->seqno, seqno)) 865 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
874 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 876 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
875 877
876 goto duplicate_request; 878 goto duplicate_request;
877 } 879 }
878 880
879 in_seq = dns->rcvseq == seqno;
880
881 // new packet, queue 881 // new packet, queue
882 rcv = new dns_rcv (seqno, data, datalen); 882 rcv = new dns_rcv (seqno, data, datalen);
883 dns->receive_rep (rcv); 883 dns->receive_rep (rcv);
884 } 884 }
885 885
… …
892 pkt [offs++] = 0; pkt [offs++] = 0; 892 pkt [offs++] = 0; pkt [offs++] = 0;
893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
894 894
895 int rdlen_offs = offs += 2; 895 int rdlen_offs = offs += 2;
896 896
897 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
898 // bind doesn't compress well, so reduce further by one label length
899 dlen -= qlen;
900
901 if (dns) 897 if (dns)
902 { 898 {
899 int dlen = ntohs (dns->cfg.max_size) - offs;
900
901 // bind doesn't compress well, so reduce further by one label length
902 dlen -= qlen;
903
903 // only put data into in-order sequence packets, if 904 // only put data into in-order sequence packets, if
904 // we receive out-of-order packets we generate empty 905 // we receive out-of-order packets we generate empty
905 // replies 906 // replies
906 while (dlen > 1 && !dns->snddq.empty () && in_seq) 907 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
908 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
907 { 909 {
910 dns->repseq = seqno;
911
912 while (dlen > 1 && !dns->snddq.empty ())
913 {
908 int txtlen = dlen <= 255 ? dlen - 1 : 255; 914 int txtlen = dlen <= 255 ? dlen - 1 : 255;
909 915
910 if (txtlen > dns->snddq.size ()) 916 if (txtlen > dns->snddq.size ())
911 txtlen = dns->snddq.size (); 917 txtlen = dns->snddq.size ();
912 918
913 pkt[offs++] = txtlen; 919 pkt[offs++] = txtlen;
914 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 920 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
915 offs += txtlen; 921 offs += txtlen;
916 dns->snddq.remove (txtlen); 922 dns->snddq.remove (txtlen);
917 923
918 dlen -= txtlen + 1; 924 dlen -= txtlen + 1;
925 }
919 } 926 }
920 927
921 // avoid empty TXT rdata 928 // avoid completely empty TXT rdata
922 if (offs == rdlen_offs) 929 if (offs == rdlen_offs)
923 pkt[offs++] = 0; 930 pkt[offs++] = 0;
924 931
925 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 932 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
926 } 933 }
… …
1015 if (dns->send_interval > MAX_SEND_INTERVAL) 1022 if (dns->send_interval > MAX_SEND_INTERVAL)
1016 dns->send_interval = MAX_SEND_INTERVAL; 1023 dns->send_interval = MAX_SEND_INTERVAL;
1017 } 1024 }
1018 else 1025 else
1019 { 1026 {
1020#if 1 1027#if 0
1021 dns->send_interval *= 0.999; 1028 dns->send_interval *= 0.999;
1022#endif 1029#endif
1023 if (dns->send_interval < MIN_SEND_INTERVAL)
1024 dns->send_interval = MIN_SEND_INTERVAL;
1025
1026 // the latency surely puts an upper bound on 1030 // the latency surely puts an upper bound on
1027 // the minimum send interval 1031 // the minimum send interval
1028 double latency = NOW - (*i)->sent; 1032 double latency = NOW - (*i)->sent;
1033
1034 if (latency < dns->min_latency)
1029 dns->last_latency = latency; 1035 dns->min_latency = latency;
1030 1036
1031 if (dns->send_interval > latency) 1037 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1038 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1039
1040 if (dns->send_interval < conf.dns_send_interval)
1032 dns->send_interval = latency; 1041 dns->send_interval = conf.dns_send_interval;
1033 } 1042 }
1034 1043
1035 delete *i; 1044 delete *i;
1036 dns_sndpq.erase (i); 1045 dns_sndpq.erase (i);
1037 1046
… …
1170} 1179}
1171 1180
1172bool 1181bool
1173vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1182vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1174{ 1183{
1175 int client = ntohs (si.port); 1184 int client = ntohl (si.host);
1176 1185
1177 assert (0 < client && client <= conns.size ()); 1186 assert (0 < client && client <= conns.size ());
1178 1187
1179 connection *c = conns [client - 1]; 1188 connection *c = conns [client - 1];
1180 1189
1181 if (!c->dns) 1190 if (!c->dns)
1182 c->dns = new dns_connection (c); 1191 c->dns = new dns_connection (c);
1183 1192
1184 if (!c->dns->snddq.put (pkt)) 1193 if (c->dns->snddq.put (pkt))
1185 return false;
1186
1187 c->dns->tw.trigger (); 1194 c->dns->tw.trigger ();
1188 1195
1196 // always return true even if the buffer overflows
1189 return true; 1197 return true;
1190} 1198}
1191 1199
1192void 1200void
1193connection::dnsv4_reset_connection () 1201connection::dnsv4_reset_connection ()
… …
1219 if (!send) 1227 if (!send)
1220 { 1228 {
1221 send = r; 1229 send = r;
1222 1230
1223 r->retry++; 1231 r->retry++;
1224 r->timeout = NOW + (r->retry * last_latency * 8.); 1232 r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
1225 1233
1226 // the following code changes the query section a bit, forcing 1234 // the following code changes the query section a bit, forcing
1227 // the forwarder to generate a new request 1235 // the forwarder to generate a new request
1228 if (r->stdhdr) 1236 if (r->stdhdr)
1229 { 1237 {
1230 //printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);printf ("reencoded header for ID %d retry %d:%d:%d\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry); 1238 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1231 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1239 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1232 } 1240 }
1233 } 1241 }
1234 } 1242 }
1235 else 1243 else
1236 NEXT (r->timeout); 1244 NEXT (r->timeout);
1237 } 1245 }
1238 1246
1239 if (last_sent + send_interval <= NOW)
1240 {
1241 if (!send) 1247 if (!send)
1248 {
1249 // generate a new packet, if wise
1250
1251 if (!established)
1242 { 1252 {
1243 // generate a new packet, if wise 1253 if (vpn->dns_sndpq.empty ())
1244
1245 if (!established)
1246 { 1254 {
1247 if (vpn->dns_sndpq.empty ())
1248 {
1249 send = new dns_snd (this); 1255 send = new dns_snd (this);
1250 1256
1251 cfg.reset (THISNODE->id); 1257 cfg.reset (THISNODE->id);
1252 send->gen_syn_req (); 1258 send->gen_syn_req ();
1253 }
1254 } 1259 }
1255 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1260 }
1261 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1256 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1262 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1263 {
1264 if (last_sent + send_interval <= NOW)
1257 { 1265 {
1258 //printf ("sending data request etc.\n"); //D 1266 //printf ("sending data request etc.\n"); //D
1259 if (!snddq.empty ()) 1267 if (!snddq.empty () || last_received + 1. > NOW)
1260 { 1268 {
1261 poll_interval = send_interval; 1269 poll_interval = send_interval;
1262 NEXT (NOW + send_interval); 1270 NEXT (NOW + send_interval);
1263 } 1271 }
1264 1272
1265 send = new dns_snd (this); 1273 send = new dns_snd (this);
1266 send->gen_stream_req (sndseq, snddq); 1274 send->gen_stream_req (sndseq, snddq);
1267 send->timeout = NOW + last_latency * 8.; 1275 send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1268 1276
1269 sndseq = (sndseq + 1) & SEQNO_MASK; 1277 sndseq = (sndseq + 1) & SEQNO_MASK;
1270 } 1278 }
1271 1279 else
1272 if (send) 1280 NEXT (last_sent + send_interval);
1273 vpn->dns_sndpq.push_back (send);
1274 } 1281 }
1275 1282
1276 if (send) 1283 if (send)
1277 { 1284 vpn->dns_sndpq.push_back (send);
1285 }
1286
1287 if (send)
1288 {
1278 last_sent = NOW; 1289 last_sent = NOW;
1279 sendto (vpn->dnsv4_fd, 1290 sendto (vpn->dnsv4_fd,
1280 send->pkt->at (0), send->pkt->len, 0, 1291 send->pkt->at (0), send->pkt->len, 0,
1281 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1292 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1282 }
1283 } 1293 }
1284 else
1285 NEXT (last_sent + send_interval);
1286 1294
1287 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1295 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1288 poll_interval, send_interval, next - NOW, 1296 poll_interval, send_interval, next - NOW,
1289 vpn->dns_sndpq.size (), snddq.size ()); 1297 vpn->dns_sndpq.size (), snddq.size (),
1298 rcvpq.size ());
1290 1299
1291 // TODO: no idea when this happens, but when next < NOW, we have a problem 1300 // TODO: no idea when this happens, but when next < NOW, we have a problem
1301 // doesn't seem to happen anymore
1292 if (next < NOW + 0.0001) 1302 if (next < NOW + 0.001)
1293 next = NOW + 0.1; 1303 next = NOW + 0.1;
1294 1304
1295 w.start (next); 1305 w.start (next);
1296} 1306}
1297 1307

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