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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.26 by pcg, Tue Mar 8 17:25:27 2005 UTC vs.
Revision 1.31 by pcg, Tue Mar 15 11:43:38 2005 UTC

… …
44 44
45#include "netcompat.h" 45#include "netcompat.h"
46 46
47#include "vpn.h" 47#include "vpn.h"
48 48
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 49#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
51#define ACTIVITY_INTERVAL 5. 50#define ACTIVITY_INTERVAL 5.
51
52#define TIMEOUT_FACTOR 2.
52 53
53#define INITIAL_TIMEOUT 0.1 // retry timeouts 54#define INITIAL_TIMEOUT 0.1 // retry timeouts
54#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 55#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
55 56
56#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests 57#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
57#define MAX_SEND_INTERVAL 0.5 // optimistic? 58#define MAX_SEND_INTERVAL 2. // optimistic?
58 59
59#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate 60#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
60#define MAX_OUTSTANDING 20 // max. outstanding requests 61#define MAX_OUTSTANDING 100 // max. outstanding requests
61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 62#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 63#define MAX_BACKLOG (32*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
63 64
64#define MAX_DOMAIN_SIZE 200 // 255 is legal limit, but bind doesn't compress well 65#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 66// 240 leaves about 4 bytes of server reply data
66// every two request bytes less give room for one reply byte 67// every two request bytes less give room for one reply byte
67 68
68#define SEQNO_MASK 0x3fff 69#define SEQNO_MASK 0x0fff
69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 70#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
70 71
71#define MAX_LBL_SIZE 63 72#define MAX_LBL_SIZE 63
72#define MAX_PKT_SIZE 512 73#define MAX_PKT_SIZE 512
73 74
… …
424 u16 max_size; 425 u16 max_size;
425 u8 seq_cdc; 426 u8 seq_cdc;
426 u8 req_cdc; 427 u8 req_cdc;
427 428
428 u8 rep_cdc; 429 u8 rep_cdc;
430 u8 delay; // time in 0.01s units that the server may delay replying packets
429 u8 r2, r3, r4; 431 u8 r3, r4;
430 432
431 u8 r5, r6, r7, r8; 433 u8 r5, r6, r7, r8;
432 434
433 void reset (int clientid); 435 void reset (int clientid);
434 bool valid (); 436 bool valid ();
… …
449 flags = 0; 451 flags = 0;
450 def_ttl = 0; 452 def_ttl = 0;
451 seq_cdc = 26; 453 seq_cdc = 26;
452 req_cdc = 62; 454 req_cdc = 62;
453 rep_cdc = 0; 455 rep_cdc = 0;
454 max_size = ntohs (MAX_PKT_SIZE); 456 max_size = htons (MAX_PKT_SIZE);
455 client = ntohs (clientid); 457 client = htons (clientid);
456 uid = next_uid++; 458 uid = next_uid++;
459 delay = 0;
457 460
458 r2 = r3 = r4 = 0; 461 r3 = r4 = 0;
459 r4 = r5 = r6 = r7 = 0; 462 r4 = r5 = r6 = r7 = 0;
460} 463}
461 464
462bool dns_cfg::valid () 465bool dns_cfg::valid ()
463{ 466{
… …
466 && id3 == 'P' 469 && id3 == 'P'
467 && id4 == 'E' 470 && id4 == 'E'
468 && seq_cdc == 26 471 && seq_cdc == 26
469 && req_cdc == 62 472 && req_cdc == 62
470 && rep_cdc == 0 473 && rep_cdc == 0
471 && version == 1 474 && version == 1;
472 && max_size == ntohs (MAX_PKT_SIZE);
473} 475}
474 476
475struct dns_packet : net_packet 477struct dns_packet : net_packet
476{ 478{
477 u16 id; 479 u16 id;
… …
553 double min_latency; 555 double min_latency;
554 double poll_interval, send_interval; 556 double poll_interval, send_interval;
555 557
556 vector<dns_rcv *> rcvpq; 558 vector<dns_rcv *> rcvpq;
557 559
558 byte_stream rcvdq; int rcvseq; 560 byte_stream rcvdq; int rcvseq; int repseq;
559 byte_stream snddq; int sndseq; 561 byte_stream snddq; int sndseq;
560 562
561 void time_cb (time_watcher &w); time_watcher tw; 563 void time_cb (time_watcher &w); time_watcher tw;
562 void receive_rep (dns_rcv *r); 564 void receive_rep (dns_rcv *r);
563 565
… …
720///////////////////////////////////////////////////////////////////////////// 722/////////////////////////////////////////////////////////////////////////////
721 723
722dns_connection::dns_connection (connection *c) 724dns_connection::dns_connection (connection *c)
723: c (c) 725: c (c)
724, rcvdq (MAX_BACKLOG * 2) 726, rcvdq (MAX_BACKLOG * 2)
725, snddq (MAX_BACKLOG * 2) 727, snddq (MAX_BACKLOG)
726, tw (this, &dns_connection::time_cb) 728, tw (this, &dns_connection::time_cb)
727{ 729{
728 vpn = c->vpn; 730 vpn = c->vpn;
729 731
730 established = false; 732 established = false;
731 733
732 rcvseq = sndseq = 0; 734 rcvseq = repseq = sndseq = 0;
733 735
734 last_sent = last_received = 0; 736 last_sent = last_received = 0;
735 poll_interval = MIN_POLL_INTERVAL; 737 poll_interval = 0.5; // starting here
736 send_interval = 0.5; // starting rate 738 send_interval = 0.5; // starting rate
737 min_latency = INITIAL_TIMEOUT; 739 min_latency = INITIAL_TIMEOUT;
738} 740}
739 741
740dns_connection::~dns_connection () 742dns_connection::~dns_connection ()
… …
855 if (0 < client && client <= conns.size ()) 857 if (0 < client && client <= conns.size ())
856 { 858 {
857 connection *c = conns [client - 1]; 859 connection *c = conns [client - 1];
858 dns_connection *dns = c->dns; 860 dns_connection *dns = c->dns;
859 dns_rcv *rcv; 861 dns_rcv *rcv;
860 bool in_seq;
861 862
862 if (dns) 863 if (dns)
863 { 864 {
864 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 865 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
865 if (SEQNO_EQ ((*i)->seqno, seqno)) 866 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
876 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 877 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
877 878
878 goto duplicate_request; 879 goto duplicate_request;
879 } 880 }
880 881
881 in_seq = dns->rcvseq == seqno;
882
883 // new packet, queue 882 // new packet, queue
884 rcv = new dns_rcv (seqno, data, datalen); 883 rcv = new dns_rcv (seqno, data, datalen);
885 dns->receive_rep (rcv); 884 dns->receive_rep (rcv);
886 } 885 }
887 886
… …
894 pkt [offs++] = 0; pkt [offs++] = 0; 893 pkt [offs++] = 0; pkt [offs++] = 0;
895 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 894 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
896 895
897 int rdlen_offs = offs += 2; 896 int rdlen_offs = offs += 2;
898 897
899 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
900 // bind doesn't compress well, so reduce further by one label length
901 dlen -= qlen;
902
903 if (dns) 898 if (dns)
904 { 899 {
900 int dlen = ntohs (dns->cfg.max_size) - offs;
901
902 // bind doesn't compress well, so reduce further by one label length
903 dlen -= qlen;
904
905 // only put data into in-order sequence packets, if 905 // only put data into in-order sequence packets, if
906 // we receive out-of-order packets we generate empty 906 // we receive out-of-order packets we generate empty
907 // replies 907 // replies
908 while (dlen > 1 && !dns->snddq.empty () && in_seq) 908 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
909 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
909 { 910 {
911 dns->repseq = seqno;
912
913 while (dlen > 1 && !dns->snddq.empty ())
914 {
910 int txtlen = dlen <= 255 ? dlen - 1 : 255; 915 int txtlen = dlen <= 255 ? dlen - 1 : 255;
911 916
912 if (txtlen > dns->snddq.size ()) 917 if (txtlen > dns->snddq.size ())
913 txtlen = dns->snddq.size (); 918 txtlen = dns->snddq.size ();
914 919
915 pkt[offs++] = txtlen; 920 pkt[offs++] = txtlen;
916 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 921 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
917 offs += txtlen; 922 offs += txtlen;
918 dns->snddq.remove (txtlen); 923 dns->snddq.remove (txtlen);
919 924
920 dlen -= txtlen + 1; 925 dlen -= txtlen + 1;
926 }
921 } 927 }
922 928
923 // avoid empty TXT rdata 929 // avoid completely empty TXT rdata
924 if (offs == rdlen_offs) 930 if (offs == rdlen_offs)
925 pkt[offs++] = 0; 931 pkt[offs++] = 0;
926 932
927 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 933 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
928 } 934 }
… …
1020 else 1026 else
1021 { 1027 {
1022#if 0 1028#if 0
1023 dns->send_interval *= 0.999; 1029 dns->send_interval *= 0.999;
1024#endif 1030#endif
1025 if (dns->send_interval < MIN_SEND_INTERVAL)
1026 dns->send_interval = MIN_SEND_INTERVAL;
1027
1028 // the latency surely puts an upper bound on 1031 // the latency surely puts an upper bound on
1029 // the minimum send interval 1032 // the minimum send interval
1030 double latency = NOW - (*i)->sent; 1033 double latency = NOW - (*i)->sent;
1031 1034
1032 if (latency < dns->min_latency) 1035 if (latency < dns->min_latency)
1033 dns->min_latency = latency; 1036 dns->min_latency = latency;
1034 1037
1035 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1038 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
1036 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1039 dns->send_interval = dns->min_latency * LATENCY_FACTOR;
1040
1041 if (dns->send_interval < MIN_SEND_INTERVAL)
1042 dns->send_interval = MIN_SEND_INTERVAL;
1037 } 1043 }
1038 1044
1039 delete *i; 1045 delete *i;
1040 dns_sndpq.erase (i); 1046 dns_sndpq.erase (i);
1041 1047
… …
1183 connection *c = conns [client - 1]; 1189 connection *c = conns [client - 1];
1184 1190
1185 if (!c->dns) 1191 if (!c->dns)
1186 c->dns = new dns_connection (c); 1192 c->dns = new dns_connection (c);
1187 1193
1188 if (!c->dns->snddq.put (pkt)) 1194 if (c->dns->snddq.put (pkt))
1189 return false;
1190
1191 c->dns->tw.trigger (); 1195 c->dns->tw.trigger ();
1192 1196
1197 // always return true even if the buffer overflows
1193 return true; 1198 return true;
1194} 1199}
1195 1200
1196void 1201void
1197connection::dnsv4_reset_connection () 1202connection::dnsv4_reset_connection ()
… …
1223 if (!send) 1228 if (!send)
1224 { 1229 {
1225 send = r; 1230 send = r;
1226 1231
1227 r->retry++; 1232 r->retry++;
1228 r->timeout = NOW + (r->retry * min_latency * 8.); 1233 r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR);
1229 1234
1230 // the following code changes the query section a bit, forcing 1235 // the following code changes the query section a bit, forcing
1231 // the forwarder to generate a new request 1236 // the forwarder to generate a new request
1232 if (r->stdhdr) 1237 if (r->stdhdr)
1233 { 1238 {
1234 //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); 1239 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1235 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1240 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1236 } 1241 }
1237 } 1242 }
1238 } 1243 }
1239 else 1244 else
1240 NEXT (r->timeout); 1245 NEXT (r->timeout);
1241 } 1246 }
1242 1247
1243 if (last_sent + send_interval <= NOW)
1244 {
1245 if (!send) 1248 if (!send)
1249 {
1250 // generate a new packet, if wise
1251
1252 if (!established)
1246 { 1253 {
1247 // generate a new packet, if wise 1254 if (vpn->dns_sndpq.empty ())
1248
1249 if (!established)
1250 { 1255 {
1251 if (vpn->dns_sndpq.empty ())
1252 {
1253 send = new dns_snd (this); 1256 send = new dns_snd (this);
1254 1257
1255 cfg.reset (THISNODE->id); 1258 cfg.reset (THISNODE->id);
1256 send->gen_syn_req (); 1259 send->gen_syn_req ();
1257 }
1258 } 1260 }
1261 }
1259 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1262 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
1260 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1263 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1264 {
1265 if (last_sent + send_interval <= NOW)
1261 { 1266 {
1262 //printf ("sending data request etc.\n"); //D 1267 //printf ("sending data request etc.\n"); //D
1263 if (!snddq.empty () || last_received + 1. > NOW) 1268 if (!snddq.empty () || last_received + 1. > NOW)
1264 { 1269 {
1265 poll_interval = send_interval; 1270 poll_interval = send_interval;
1266 NEXT (NOW + send_interval); 1271 NEXT (NOW + send_interval);
1267 } 1272 }
1268 1273
1269 send = new dns_snd (this); 1274 send = new dns_snd (this);
1270 send->gen_stream_req (sndseq, snddq); 1275 send->gen_stream_req (sndseq, snddq);
1271 send->timeout = NOW + min_latency * 8.; 1276 send->timeout = NOW + min_latency * TIMEOUT_FACTOR;
1272 1277
1273 sndseq = (sndseq + 1) & SEQNO_MASK; 1278 sndseq = (sndseq + 1) & SEQNO_MASK;
1274 } 1279 }
1275 1280 else
1276 if (send) 1281 NEXT (last_sent + send_interval);
1277 vpn->dns_sndpq.push_back (send);
1278 } 1282 }
1279 1283
1280 if (send) 1284 if (send)
1281 { 1285 vpn->dns_sndpq.push_back (send);
1286 }
1287
1288 if (send)
1289 {
1282 last_sent = NOW; 1290 last_sent = NOW;
1291 if (rand () & 15 != 0)//D
1283 sendto (vpn->dnsv4_fd, 1292 sendto (vpn->dnsv4_fd,
1284 send->pkt->at (0), send->pkt->len, 0, 1293 send->pkt->at (0), send->pkt->len, 0,
1285 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1294 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1286 }
1287 } 1295 }
1288 else
1289 NEXT (last_sent + send_interval);
1290 1296
1291 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1297 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
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 (),
1300 rcvpq.size ());
1294 1301
1295 // 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
1296 if (next < NOW + 0.0001) 1303 if (next < NOW + 0.001)
1297 next = NOW + 0.1; 1304 next = NOW + 0.1;
1298 1305
1299 w.start (next); 1306 w.start (next);
1300} 1307}
1301 1308

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