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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.34 by pcg, Tue Mar 15 19:26:11 2005 UTC vs.
Revision 1.42 by pcg, Sat Nov 10 05:14:22 2007 UTC

… …
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
… …
47#include "vpn.h" 51#include "vpn.h"
48 52
49#define MAX_POLL_INTERVAL 5. // 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
50#define ACTIVITY_INTERVAL 5. 54#define ACTIVITY_INTERVAL 5.
51 55
52#define TIMEOUT_FACTOR 2.
53
54#define INITIAL_TIMEOUT 0.1 // retry timeouts 56#define INITIAL_TIMEOUT 0.1 // retry timeouts
55#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
56 58
57#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
58#define MAX_SEND_INTERVAL 2. // optimistic? 59#define MAX_SEND_INTERVAL 2. // optimistic?
59 60
60#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
61#define MAX_OUTSTANDING 100 // max. outstanding requests
62#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
63#define MAX_BACKLOG (32*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
64 63
65#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
66// 240 leaves about 4 bytes of server reply data 65// 240 leaves about 4 bytes of server reply data
67// every request byte less give room for two reply bytes 66// every request byte less give room for two reply bytes
68 67
… …
462 r4 = r5 = r6 = r7 = 0; 461 r4 = r5 = r6 = r7 = 0;
463} 462}
464 463
465bool dns_cfg::valid () 464bool dns_cfg::valid ()
466{ 465{
466 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented.
467 return id1 == 'G' 468 return id1 == 'G'
468 && id2 == 'V' 469 && id2 == 'V'
469 && id3 == 'P' 470 && id3 == 'P'
470 && id4 == 'E' 471 && id4 == 'E'
471 && seq_cdc == 26 472 && seq_cdc == 26
… …
558 vector<dns_rcv *> rcvpq; 559 vector<dns_rcv *> rcvpq;
559 560
560 byte_stream rcvdq; int rcvseq; int repseq; 561 byte_stream rcvdq; int rcvseq; int repseq;
561 byte_stream snddq; int sndseq; 562 byte_stream snddq; int sndseq;
562 563
563 void time_cb (time_watcher &w); time_watcher tw; 564 void time_cb (ev::timer &w, int revents); ev::timer tw;
564 void receive_rep (dns_rcv *r); 565 void receive_rep (dns_rcv *r);
565 566
566 dns_connection (connection *c); 567 dns_connection (connection *c);
567 ~dns_connection (); 568 ~dns_connection ();
568}; 569};
… …
587: dns (dns) 588: dns (dns)
588{ 589{
589 timeout = 0; 590 timeout = 0;
590 retry = 0; 591 retry = 0;
591 seqno = 0; 592 seqno = 0;
592 sent = NOW; 593 sent = ev::ev_now ();
593 stdhdr = false; 594 stdhdr = false;
594 595
595 pkt = new dns_packet; 596 pkt = new dns_packet;
596 597
597 pkt->id = next_id (); 598 pkt->id = next_id ();
… …
628void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 629void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
629{ 630{
630 stdhdr = true; 631 stdhdr = true;
631 this->seqno = seqno; 632 this->seqno = seqno;
632 633
633 timeout = NOW + INITIAL_TIMEOUT; 634 timeout = ev::ev_now () + INITIAL_TIMEOUT;
634 635
635 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
636 pkt->qdcount = htons (1); 637 pkt->qdcount = htons (1);
637 638
638 int offs = 6*2; 639 int offs = 6*2;
… …
673 pkt->len = offs; 674 pkt->len = offs;
674} 675}
675 676
676void dns_snd::gen_syn_req () 677void dns_snd::gen_syn_req ()
677{ 678{
678 timeout = NOW + INITIAL_SYN_TIMEOUT; 679 timeout = ev::ev_now () + INITIAL_SYN_TIMEOUT;
679 680
680 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
681 pkt->qdcount = htons (1); 682 pkt->qdcount = htons (1);
682 683
683 int offs = 6 * 2; 684 int offs = 6 * 2;
… …
749 750
750void dns_connection::receive_rep (dns_rcv *r) 751void dns_connection::receive_rep (dns_rcv *r)
751{ 752{
752 if (r->datalen) 753 if (r->datalen)
753 { 754 {
754 last_received = NOW; 755 last_received = ev::ev_now ();
755 tw.trigger (); 756 tw ();
756 757
757 poll_interval = send_interval; 758 poll_interval = send_interval;
758 } 759 }
759 else 760 else
760 { 761 {
… …
770 771
771 // find next packet 772 // find next packet
772 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 773 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
773 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 774 if (SEQNO_EQ (rcvseq, (*i)->seqno))
774 { 775 {
776 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
775 // enter the packet into our input stream 777 // enter the packet into our input stream
776 r = *i; 778 r = *i;
777 779
778 // remove the oldest packet, look forward, as it's oldest first 780 // remove the oldest packet, look forward, as it's oldest first
779 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j) 781 for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
780 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 782 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
781 { 783 {
784 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
782 delete *j; 785 delete *j;
783 rcvpq.erase (j); 786 rcvpq.erase (j);
784 break; 787 break;
785 } 788 }
786 789
… …
1014 { 1017 {
1015 dns_connection *dns = (*i)->dns; 1018 dns_connection *dns = (*i)->dns;
1016 connection *c = dns->c; 1019 connection *c = dns->c;
1017 int seqno = (*i)->seqno; 1020 int seqno = (*i)->seqno;
1018 u8 data[MAXSIZE], *datap = data; 1021 u8 data[MAXSIZE], *datap = data;
1022 //printf ("rcv pkt %x\n", seqno);//D
1019 1023
1020 if ((*i)->retry) 1024 if ((*i)->retry)
1021 { 1025 {
1022 dns->send_interval *= 1.01; 1026 dns->send_interval *= 1.01;
1023 if (dns->send_interval > MAX_SEND_INTERVAL) 1027 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1028#if 0 1032#if 0
1029 dns->send_interval *= 0.999; 1033 dns->send_interval *= 0.999;
1030#endif 1034#endif
1031 // the latency surely puts an upper bound on 1035 // the latency surely puts an upper bound on
1032 // the minimum send interval 1036 // the minimum send interval
1033 double latency = NOW - (*i)->sent; 1037 double latency = ev::ev_now () - (*i)->sent;
1034 1038
1035 if (latency < dns->min_latency) 1039 if (latency < dns->min_latency)
1036 dns->min_latency = latency; 1040 dns->min_latency = latency;
1037 1041
1038 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1042 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1039 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1043 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1040 1044
1041 if (dns->send_interval < MIN_SEND_INTERVAL) 1045 if (dns->send_interval < conf.dns_send_interval)
1042 dns->send_interval = MIN_SEND_INTERVAL; 1046 dns->send_interval = conf.dns_send_interval;
1043 } 1047 }
1044 1048
1045 delete *i; 1049 delete *i;
1046 dns_sndpq.erase (i); 1050 dns_sndpq.erase (i);
1047 1051
… …
1152 break; 1156 break;
1153 } 1157 }
1154} 1158}
1155 1159
1156void 1160void
1157vpn::dnsv4_ev (io_watcher &w, short revents) 1161vpn::dnsv4_ev (ev::io &w, int revents)
1158{ 1162{
1159 if (revents & EVENT_READ) 1163 if (revents & EV_READ)
1160 { 1164 {
1161 dns_packet *pkt = new dns_packet; 1165 dns_packet *pkt = new dns_packet;
1162 struct sockaddr_in sa; 1166 struct sockaddr_in sa;
1163 socklen_t sa_len = sizeof (sa); 1167 socklen_t sa_len = sizeof (sa);
1164 1168
… …
1190 1194
1191 if (!c->dns) 1195 if (!c->dns)
1192 c->dns = new dns_connection (c); 1196 c->dns = new dns_connection (c);
1193 1197
1194 if (c->dns->snddq.put (pkt)) 1198 if (c->dns->snddq.put (pkt))
1195 c->dns->tw.trigger (); 1199 c->dns->tw ();
1196 1200
1197 // always return true even if the buffer overflows 1201 // always return true even if the buffer overflows
1198 return true; 1202 return true;
1199} 1203}
1200 1204
… …
1205} 1209}
1206 1210
1207#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1211#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1208 1212
1209void 1213void
1210dns_connection::time_cb (time_watcher &w) 1214dns_connection::time_cb (ev::timer &w, int revents)
1211{ 1215{
1212 // servers have to be polled 1216 // servers have to be polled
1213 if (THISNODE->dns_port) 1217 if (THISNODE->dns_port)
1214 return; 1218 return;
1215 1219
1216 // check for timeouts and (re)transmit 1220 // check for timeouts and (re)transmit
1217 tstamp next = NOW + poll_interval; 1221 tstamp next = ev::now () + poll_interval;
1218 dns_snd *send = 0; 1222 dns_snd *send = 0;
1219 1223
1220 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1224 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1221 i != vpn->dns_sndpq.end (); 1225 i != vpn->dns_sndpq.end ();
1222 ++i) 1226 ++i)
1223 { 1227 {
1224 dns_snd *r = *i; 1228 dns_snd *r = *i;
1225 1229
1226 if (r->timeout <= NOW) 1230 if (r->timeout <= ev::ev_now ())
1227 { 1231 {
1228 if (!send) 1232 if (!send)
1229 { 1233 {
1230 send = r; 1234 send = r;
1231 1235
1232 r->retry++; 1236 r->retry++;
1233 r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR); 1237 r->timeout = ev::ev_now () + (r->retry * min_latency * conf.dns_timeout_factor);
1238 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - ev::ev_now ());//D
1234 1239
1235 // the following code changes the query section a bit, forcing 1240 // the following code changes the query section a bit, forcing
1236 // the forwarder to generate a new request 1241 // the forwarder to generate a new request
1237 if (r->stdhdr) 1242 if (r->stdhdr)
1238 {
1239 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1240 //encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry); 1243 encode_header ((char *)r->pkt->at (6 * 2 + 1), THISNODE->id, r->seqno, r->retry);
1241 }
1242 } 1244 }
1243 } 1245 }
1244 else 1246 else
1245 NEXT (r->timeout); 1247 NEXT (r->timeout);
1246 } 1248 }
… …
1257 1259
1258 cfg.reset (THISNODE->id); 1260 cfg.reset (THISNODE->id);
1259 send->gen_syn_req (); 1261 send->gen_syn_req ();
1260 } 1262 }
1261 } 1263 }
1262 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1264 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1263 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1265 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1264 { 1266 {
1265 if (last_sent + send_interval <= NOW) 1267 if (last_sent + send_interval <= ev::ev_now ())
1266 { 1268 {
1267 //printf ("sending data request etc.\n"); //D 1269 //printf ("sending data request etc.\n"); //D
1268 if (!snddq.empty () || last_received + 1. > NOW) 1270 if (!snddq.empty () || last_received + 1. > ev::ev_now ())
1269 { 1271 {
1270 poll_interval = send_interval; 1272 poll_interval = send_interval;
1271 NEXT (NOW + send_interval); 1273 NEXT (ev::ev_now () + send_interval);
1272 } 1274 }
1273 1275
1274 send = new dns_snd (this); 1276 send = new dns_snd (this);
1275 send->gen_stream_req (sndseq, snddq); 1277 send->gen_stream_req (sndseq, snddq);
1276 send->timeout = NOW + min_latency * TIMEOUT_FACTOR; 1278 send->timeout = ev::ev_now () + min_latency * conf.dns_timeout_factor;
1279 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - ev::ev_now (), min_latency, conf.dns_timeout_factor);//D
1277 1280
1278 sndseq = (sndseq + 1) & SEQNO_MASK; 1281 sndseq = (sndseq + 1) & SEQNO_MASK;
1279 } 1282 }
1280 else 1283 else
1281 NEXT (last_sent + send_interval); 1284 NEXT (last_sent + send_interval);
… …
1285 vpn->dns_sndpq.push_back (send); 1288 vpn->dns_sndpq.push_back (send);
1286 } 1289 }
1287 1290
1288 if (send) 1291 if (send)
1289 { 1292 {
1290 last_sent = NOW; 1293 last_sent = ev::ev_now ();
1291 sendto (vpn->dnsv4_fd, 1294 sendto (vpn->dnsv4_fd,
1292 send->pkt->at (0), send->pkt->len, 0, 1295 send->pkt->at (0), send->pkt->len, 0,
1293 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1296 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1294 } 1297 }
1295 1298
1296 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1299 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1297 poll_interval, send_interval, next - NOW, 1300 poll_interval, send_interval, next - ev::ev_now (),
1298 vpn->dns_sndpq.size (), snddq.size (), 1301 vpn->dns_sndpq.size (), snddq.size (),
1299 rcvpq.size ()); 1302 rcvpq.size ());
1300 1303
1301 // TODO: no idea when this happens, but when next < NOW, we have a problem 1304 // TODO: no idea when this happens, but when next < ev::ev_now (), we have a problem
1302 if (next < NOW + 0.001) 1305 // doesn't seem to happen anymore
1303 next = NOW + 0.1; 1306 if (next < ev::ev_now () + 0.001)
1307 next = ev::ev_now () + 0.1;
1304 1308
1305 w.start (next); 1309 w.start (next - ev::ev_now ());
1306} 1310}
1307 1311
1308#endif 1312#endif
1309 1313

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