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/cvs/gvpe/src/vpn_dns.C
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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 1.30 by pcg, Mon Mar 14 17:40:01 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.
52 51
53#define INITIAL_TIMEOUT 0.1 // retry timeouts 52#define INITIAL_TIMEOUT 0.1 // retry timeouts
54#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn
55 54
56#define MIN_SEND_INTERVAL 0.01 // wait at least this time between sending requests 55#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
57#define MAX_SEND_INTERVAL 0.5 // optimistic? 56#define MAX_SEND_INTERVAL 2. // optimistic?
58 57
58#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
59#define MAX_OUTSTANDING 10 // max. outstanding requests 59#define MAX_OUTSTANDING 2 // max. outstanding requests
60#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 60#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 61#define MAX_BACKLOG (100*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
62 62
63#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well 63#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 64// 240 leaves about 4 bytes of server reply data
65// every two request bytes less give room for one reply byte 65// every two request bytes less give room for one reply byte
66 66
67#define SEQNO_MASK 0x3fff 67#define SEQNO_MASK 0x3fff
68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 68#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
… …
423 u16 max_size; 423 u16 max_size;
424 u8 seq_cdc; 424 u8 seq_cdc;
425 u8 req_cdc; 425 u8 req_cdc;
426 426
427 u8 rep_cdc; 427 u8 rep_cdc;
428 u8 delay; // time in 0.01s units that the server may delay replying packets
428 u8 r2, r3, r4; 429 u8 r3, r4;
429 430
430 u8 r5, r6, r7, r8; 431 u8 r5, r6, r7, r8;
431 432
432 void reset (int clientid); 433 void reset (int clientid);
433 bool valid (); 434 bool valid ();
… …
448 flags = 0; 449 flags = 0;
449 def_ttl = 0; 450 def_ttl = 0;
450 seq_cdc = 26; 451 seq_cdc = 26;
451 req_cdc = 62; 452 req_cdc = 62;
452 rep_cdc = 0; 453 rep_cdc = 0;
453 max_size = ntohs (MAX_PKT_SIZE); 454 max_size = htons (MAX_PKT_SIZE);
454 client = ntohs (clientid); 455 client = htons (clientid);
455 uid = next_uid++; 456 uid = next_uid++;
457 delay = 0;
456 458
457 r2 = r3 = r4 = 0; 459 r3 = r4 = 0;
458 r4 = r5 = r6 = r7 = 0; 460 r4 = r5 = r6 = r7 = 0;
459} 461}
460 462
461bool dns_cfg::valid () 463bool dns_cfg::valid ()
462{ 464{
… …
465 && id3 == 'P' 467 && id3 == 'P'
466 && id4 == 'E' 468 && id4 == 'E'
467 && seq_cdc == 26 469 && seq_cdc == 26
468 && req_cdc == 62 470 && req_cdc == 62
469 && rep_cdc == 0 471 && rep_cdc == 0
470 && version == 1 472 && version == 1;
471 && max_size == ntohs (MAX_PKT_SIZE);
472} 473}
473 474
474struct dns_packet : net_packet 475struct dns_packet : net_packet
475{ 476{
476 u16 id; 477 u16 id;
… …
547 548
548 bool established; 549 bool established;
549 550
550 tstamp last_received; 551 tstamp last_received;
551 tstamp last_sent; 552 tstamp last_sent;
552 double last_latency; 553 double min_latency;
553 double poll_interval, send_interval; 554 double poll_interval, send_interval;
554 555
555 vector<dns_rcv *> rcvpq; 556 vector<dns_rcv *> rcvpq;
556 557
557 byte_stream rcvdq; int rcvseq; 558 byte_stream rcvdq; int rcvseq;
… …
729 established = false; 730 established = false;
730 731
731 rcvseq = sndseq = 0; 732 rcvseq = sndseq = 0;
732 733
733 last_sent = last_received = 0; 734 last_sent = last_received = 0;
734 poll_interval = MIN_POLL_INTERVAL; 735 poll_interval = 0.5; // starting here
735 send_interval = 0.5; // starting rate 736 send_interval = 0.5; // starting rate
736 last_latency = INITIAL_TIMEOUT; 737 min_latency = INITIAL_TIMEOUT;
737} 738}
738 739
739dns_connection::~dns_connection () 740dns_connection::~dns_connection ()
740{ 741{
741 for (vector<dns_rcv *>::iterator i = rcvpq.begin (); 742 for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
… …
754 poll_interval = send_interval; 755 poll_interval = send_interval;
755 } 756 }
756 else 757 else
757 { 758 {
758 poll_interval *= 1.5; 759 poll_interval *= 1.5;
760
759 if (poll_interval > MAX_POLL_INTERVAL) 761 if (poll_interval > MAX_POLL_INTERVAL)
760 poll_interval = MAX_POLL_INTERVAL; 762 poll_interval = MAX_POLL_INTERVAL;
761 } 763 }
762 764
763 rcvpq.push_back (r); 765 rcvpq.push_back (r);
… …
892 pkt [offs++] = 0; pkt [offs++] = 0; 894 pkt [offs++] = 0; pkt [offs++] = 0;
893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 895 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
894 896
895 int rdlen_offs = offs += 2; 897 int rdlen_offs = offs += 2;
896 898
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) 899 if (dns)
902 { 900 {
901 int dlen = ntohs (dns->cfg.max_size) - offs;
902
903 // bind doesn't compress well, so reduce further by one label length
904 dlen -= qlen;
905
903 // only put data into in-order sequence packets, if 906 // only put data into in-order sequence packets, if
904 // we receive out-of-order packets we generate empty 907 // we receive out-of-order packets we generate empty
905 // replies 908 // replies
906 while (dlen > 1 && !dns->snddq.empty () && in_seq) 909 while (dlen > 1 && !dns->snddq.empty () && in_seq)
907 { 910 {
… …
1015 if (dns->send_interval > MAX_SEND_INTERVAL) 1018 if (dns->send_interval > MAX_SEND_INTERVAL)
1016 dns->send_interval = MAX_SEND_INTERVAL; 1019 dns->send_interval = MAX_SEND_INTERVAL;
1017 } 1020 }
1018 else 1021 else
1019 { 1022 {
1020#if 1 1023#if 0
1021 dns->send_interval *= 0.999; 1024 dns->send_interval *= 0.999;
1022#endif 1025#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 1026 // the latency surely puts an upper bound on
1027 // the minimum send interval 1027 // the minimum send interval
1028 double latency = NOW - (*i)->sent; 1028 double latency = NOW - (*i)->sent;
1029
1030 if (latency < dns->min_latency)
1029 dns->last_latency = latency; 1031 dns->min_latency = latency;
1030 1032
1031 if (dns->send_interval > latency) 1033 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
1032 dns->send_interval = latency; 1034 dns->send_interval = dns->min_latency * LATENCY_FACTOR;
1035
1036 if (dns->send_interval < MIN_SEND_INTERVAL)
1037 dns->send_interval = MIN_SEND_INTERVAL;
1033 } 1038 }
1034 1039
1035 delete *i; 1040 delete *i;
1036 dns_sndpq.erase (i); 1041 dns_sndpq.erase (i);
1037 1042
… …
1219 if (!send) 1224 if (!send)
1220 { 1225 {
1221 send = r; 1226 send = r;
1222 1227
1223 r->retry++; 1228 r->retry++;
1224 r->timeout = NOW + (r->retry * last_latency * 8.); 1229 r->timeout = NOW + (r->retry * min_latency * 8.);
1225 1230
1226 // the following code changes the query section a bit, forcing 1231 // the following code changes the query section a bit, forcing
1227 // the forwarder to generate a new request 1232 // the forwarder to generate a new request
1228 if (r->stdhdr) 1233 if (r->stdhdr)
1229 { 1234 {
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); 1235 //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); 1236 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1232 } 1237 }
1233 } 1238 }
1234 } 1239 }
1235 else 1240 else
1236 NEXT (r->timeout); 1241 NEXT (r->timeout);
1237 } 1242 }
1238 1243
1239 if (last_sent + send_interval <= NOW)
1240 {
1241 if (!send) 1244 if (!send)
1245 {
1246 // generate a new packet, if wise
1247
1248 if (!established)
1242 { 1249 {
1243 // generate a new packet, if wise 1250 if (vpn->dns_sndpq.empty ())
1244
1245 if (!established)
1246 { 1251 {
1247 if (vpn->dns_sndpq.empty ())
1248 {
1249 send = new dns_snd (this); 1252 send = new dns_snd (this);
1250 1253
1251 cfg.reset (THISNODE->id); 1254 cfg.reset (THISNODE->id);
1252 send->gen_syn_req (); 1255 send->gen_syn_req ();
1253 }
1254 } 1256 }
1257 }
1255 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1258 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
1256 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1259 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1260 {
1261 if (last_sent + send_interval <= NOW)
1257 { 1262 {
1258 //printf ("sending data request etc.\n"); //D 1263 //printf ("sending data request etc.\n"); //D
1259 if (!snddq.empty ()) 1264 if (!snddq.empty () || last_received + 1. > NOW)
1260 { 1265 {
1261 poll_interval = send_interval; 1266 poll_interval = send_interval;
1262 NEXT (NOW + send_interval); 1267 NEXT (NOW + send_interval);
1263 } 1268 }
1264 1269
1265 send = new dns_snd (this); 1270 send = new dns_snd (this);
1266 send->gen_stream_req (sndseq, snddq); 1271 send->gen_stream_req (sndseq, snddq);
1267 send->timeout = NOW + last_latency * 8.; 1272 send->timeout = NOW + min_latency * 8.;
1268 1273
1269 sndseq = (sndseq + 1) & SEQNO_MASK; 1274 sndseq = (sndseq + 1) & SEQNO_MASK;
1270 } 1275 }
1271 1276 else
1272 if (send) 1277 NEXT (last_sent + send_interval);
1273 vpn->dns_sndpq.push_back (send);
1274 } 1278 }
1275 1279
1276 if (send) 1280 if (send)
1277 { 1281 vpn->dns_sndpq.push_back (send);
1282 }
1283
1284 if (send)
1285 {
1278 last_sent = NOW; 1286 last_sent = NOW;
1279 sendto (vpn->dnsv4_fd, 1287 sendto (vpn->dnsv4_fd,
1280 send->pkt->at (0), send->pkt->len, 0, 1288 send->pkt->at (0), send->pkt->len, 0,
1281 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1289 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1282 }
1283 } 1290 }
1284 else
1285 NEXT (last_sent + send_interval);
1286 1291
1287 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d)", 1292 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1288 poll_interval, send_interval, next - NOW, 1293 poll_interval, send_interval, next - NOW,
1289 vpn->dns_sndpq.size (), snddq.size ()); 1294 vpn->dns_sndpq.size (), snddq.size (),
1295 rcvpq.size ());
1290 1296
1291 // TODO: no idea when this happens, but when next < NOW, we have a problem 1297 // TODO: no idea when this happens, but when next < NOW, we have a problem
1292 if (next < NOW + 0.0001) 1298 if (next < NOW + 0.001)
1293 next = NOW + 0.1; 1299 next = NOW + 0.1;
1294 1300
1295 w.start (next); 1301 w.start (next);
1296} 1302}
1297 1303

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