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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.30 by pcg, Mon Mar 14 17:40:01 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
… …
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 INITIAL_TIMEOUT 0.1 // retry timeouts 56#define INITIAL_TIMEOUT 0.1 // retry timeouts
53#define INITIAL_SYN_TIMEOUT 10. // retry timeout for initial syn 57#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
54 58
55#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
56#define MAX_SEND_INTERVAL 2. // optimistic? 59#define MAX_SEND_INTERVAL 2. // optimistic?
57 60
58#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
59#define MAX_OUTSTANDING 2 // 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 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
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
… …
460 r4 = r5 = r6 = r7 = 0; 461 r4 = r5 = r6 = r7 = 0;
461} 462}
462 463
463bool dns_cfg::valid () 464bool dns_cfg::valid ()
464{ 465{
466 // although the protocol itself allows for some configurability,
467 // only the following encoding/decoding settings are implemented.
465 return id1 == 'G' 468 return id1 == 'G'
466 && id2 == 'V' 469 && id2 == 'V'
467 && id3 == 'P' 470 && id3 == 'P'
468 && id4 == 'E' 471 && id4 == 'E'
469 && seq_cdc == 26 472 && seq_cdc == 26
… …
553 double min_latency; 556 double min_latency;
554 double poll_interval, send_interval; 557 double poll_interval, send_interval;
555 558
556 vector<dns_rcv *> rcvpq; 559 vector<dns_rcv *> rcvpq;
557 560
558 byte_stream rcvdq; int rcvseq; 561 byte_stream rcvdq; int rcvseq; int repseq;
559 byte_stream snddq; int sndseq; 562 byte_stream snddq; int sndseq;
560 563
561 void time_cb (time_watcher &w); time_watcher tw; 564 void time_cb (ev::timer &w, int revents); ev::timer tw;
562 void receive_rep (dns_rcv *r); 565 void receive_rep (dns_rcv *r);
563 566
564 dns_connection (connection *c); 567 dns_connection (connection *c);
565 ~dns_connection (); 568 ~dns_connection ();
566}; 569};
… …
585: dns (dns) 588: dns (dns)
586{ 589{
587 timeout = 0; 590 timeout = 0;
588 retry = 0; 591 retry = 0;
589 seqno = 0; 592 seqno = 0;
590 sent = NOW; 593 sent = ev::ev_now ();
591 stdhdr = false; 594 stdhdr = false;
592 595
593 pkt = new dns_packet; 596 pkt = new dns_packet;
594 597
595 pkt->id = next_id (); 598 pkt->id = next_id ();
… …
626void dns_snd::gen_stream_req (int seqno, byte_stream &stream) 629void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
627{ 630{
628 stdhdr = true; 631 stdhdr = true;
629 this->seqno = seqno; 632 this->seqno = seqno;
630 633
631 timeout = NOW + INITIAL_TIMEOUT; 634 timeout = ev::ev_now () + INITIAL_TIMEOUT;
632 635
633 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 636 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
634 pkt->qdcount = htons (1); 637 pkt->qdcount = htons (1);
635 638
636 int offs = 6*2; 639 int offs = 6*2;
… …
671 pkt->len = offs; 674 pkt->len = offs;
672} 675}
673 676
674void dns_snd::gen_syn_req () 677void dns_snd::gen_syn_req ()
675{ 678{
676 timeout = NOW + INITIAL_SYN_TIMEOUT; 679 timeout = ev::ev_now () + INITIAL_SYN_TIMEOUT;
677 680
678 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 681 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
679 pkt->qdcount = htons (1); 682 pkt->qdcount = htons (1);
680 683
681 int offs = 6 * 2; 684 int offs = 6 * 2;
… …
720///////////////////////////////////////////////////////////////////////////// 723/////////////////////////////////////////////////////////////////////////////
721 724
722dns_connection::dns_connection (connection *c) 725dns_connection::dns_connection (connection *c)
723: c (c) 726: c (c)
724, rcvdq (MAX_BACKLOG * 2) 727, rcvdq (MAX_BACKLOG * 2)
725, snddq (MAX_BACKLOG * 2) 728, snddq (MAX_BACKLOG)
726, tw (this, &dns_connection::time_cb) 729, tw (this, &dns_connection::time_cb)
727{ 730{
728 vpn = c->vpn; 731 vpn = c->vpn;
729 732
730 established = false; 733 established = false;
731 734
732 rcvseq = sndseq = 0; 735 rcvseq = repseq = sndseq = 0;
733 736
734 last_sent = last_received = 0; 737 last_sent = last_received = 0;
735 poll_interval = 0.5; // starting here 738 poll_interval = 0.5; // starting here
736 send_interval = 0.5; // starting rate 739 send_interval = 0.5; // starting rate
737 min_latency = INITIAL_TIMEOUT; 740 min_latency = INITIAL_TIMEOUT;
… …
747 750
748void dns_connection::receive_rep (dns_rcv *r) 751void dns_connection::receive_rep (dns_rcv *r)
749{ 752{
750 if (r->datalen) 753 if (r->datalen)
751 { 754 {
752 last_received = NOW; 755 last_received = ev::ev_now ();
753 tw.trigger (); 756 tw ();
754 757
755 poll_interval = send_interval; 758 poll_interval = send_interval;
756 } 759 }
757 else 760 else
758 { 761 {
… …
768 771
769 // find next packet 772 // find next packet
770 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); ) 773 for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
771 if (SEQNO_EQ (rcvseq, (*i)->seqno)) 774 if (SEQNO_EQ (rcvseq, (*i)->seqno))
772 { 775 {
776 //printf ("seqno eq %x %x\n", rcvseq, (*i)->seqno);//D
773 // enter the packet into our input stream 777 // enter the packet into our input stream
774 r = *i; 778 r = *i;
775 779
776 // remove the oldest packet, look forward, as it's oldest first 780 // remove the oldest packet, look forward, as it's oldest first
777 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)
778 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW)) 782 if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
779 { 783 {
784 //printf ("seqno RR %x %x\n", (*j)->seqno, rcvseq - MAX_WINDOW);//D
780 delete *j; 785 delete *j;
781 rcvpq.erase (j); 786 rcvpq.erase (j);
782 break; 787 break;
783 } 788 }
784 789
… …
791 } 796 }
792 797
793 while (vpn_packet *pkt = rcvdq.get ()) 798 while (vpn_packet *pkt = rcvdq.get ())
794 { 799 {
795 sockinfo si; 800 sockinfo si;
796 si.host = 0x01010101; si.port = htons (c->conf->id); si.prot = PROT_DNSv4; 801 si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
797 802
798 vpn->recv_vpn_packet (pkt, si); 803 vpn->recv_vpn_packet (pkt, si);
799 804
800 delete pkt; 805 delete pkt;
801 } 806 }
… …
855 if (0 < client && client <= conns.size ()) 860 if (0 < client && client <= conns.size ())
856 { 861 {
857 connection *c = conns [client - 1]; 862 connection *c = conns [client - 1];
858 dns_connection *dns = c->dns; 863 dns_connection *dns = c->dns;
859 dns_rcv *rcv; 864 dns_rcv *rcv;
860 bool in_seq;
861 865
862 if (dns) 866 if (dns)
863 { 867 {
864 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); ) 868 for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
865 if (SEQNO_EQ ((*i)->seqno, seqno)) 869 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
876 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len); 880 memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
877 881
878 goto duplicate_request; 882 goto duplicate_request;
879 } 883 }
880 884
881 in_seq = dns->rcvseq == seqno;
882
883 // new packet, queue 885 // new packet, queue
884 rcv = new dns_rcv (seqno, data, datalen); 886 rcv = new dns_rcv (seqno, data, datalen);
885 dns->receive_rep (rcv); 887 dns->receive_rep (rcv);
886 } 888 }
887 889
… …
904 dlen -= qlen; 906 dlen -= qlen;
905 907
906 // only put data into in-order sequence packets, if 908 // only put data into in-order sequence packets, if
907 // we receive out-of-order packets we generate empty 909 // we receive out-of-order packets we generate empty
908 // replies 910 // replies
909 while (dlen > 1 && !dns->snddq.empty () && in_seq) 911 //printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
912 if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
910 { 913 {
914 dns->repseq = seqno;
915
916 while (dlen > 1 && !dns->snddq.empty ())
917 {
911 int txtlen = dlen <= 255 ? dlen - 1 : 255; 918 int txtlen = dlen <= 255 ? dlen - 1 : 255;
912 919
913 if (txtlen > dns->snddq.size ()) 920 if (txtlen > dns->snddq.size ())
914 txtlen = dns->snddq.size (); 921 txtlen = dns->snddq.size ();
915 922
916 pkt[offs++] = txtlen; 923 pkt[offs++] = txtlen;
917 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 924 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
918 offs += txtlen; 925 offs += txtlen;
919 dns->snddq.remove (txtlen); 926 dns->snddq.remove (txtlen);
920 927
921 dlen -= txtlen + 1; 928 dlen -= txtlen + 1;
929 }
922 } 930 }
923 931
924 // avoid empty TXT rdata 932 // avoid completely empty TXT rdata
925 if (offs == rdlen_offs) 933 if (offs == rdlen_offs)
926 pkt[offs++] = 0; 934 pkt[offs++] = 0;
927 935
928 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 936 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
929 } 937 }
… …
1009 { 1017 {
1010 dns_connection *dns = (*i)->dns; 1018 dns_connection *dns = (*i)->dns;
1011 connection *c = dns->c; 1019 connection *c = dns->c;
1012 int seqno = (*i)->seqno; 1020 int seqno = (*i)->seqno;
1013 u8 data[MAXSIZE], *datap = data; 1021 u8 data[MAXSIZE], *datap = data;
1022 //printf ("rcv pkt %x\n", seqno);//D
1014 1023
1015 if ((*i)->retry) 1024 if ((*i)->retry)
1016 { 1025 {
1017 dns->send_interval *= 1.01; 1026 dns->send_interval *= 1.01;
1018 if (dns->send_interval > MAX_SEND_INTERVAL) 1027 if (dns->send_interval > MAX_SEND_INTERVAL)
… …
1023#if 0 1032#if 0
1024 dns->send_interval *= 0.999; 1033 dns->send_interval *= 0.999;
1025#endif 1034#endif
1026 // the latency surely puts an upper bound on 1035 // the latency surely puts an upper bound on
1027 // the minimum send interval 1036 // the minimum send interval
1028 double latency = NOW - (*i)->sent; 1037 double latency = ev::ev_now () - (*i)->sent;
1029 1038
1030 if (latency < dns->min_latency) 1039 if (latency < dns->min_latency)
1031 dns->min_latency = latency; 1040 dns->min_latency = latency;
1032 1041
1033 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1042 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1034 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1043 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1035 1044
1036 if (dns->send_interval < MIN_SEND_INTERVAL) 1045 if (dns->send_interval < conf.dns_send_interval)
1037 dns->send_interval = MIN_SEND_INTERVAL; 1046 dns->send_interval = conf.dns_send_interval;
1038 } 1047 }
1039 1048
1040 delete *i; 1049 delete *i;
1041 dns_sndpq.erase (i); 1050 dns_sndpq.erase (i);
1042 1051
… …
1147 break; 1156 break;
1148 } 1157 }
1149} 1158}
1150 1159
1151void 1160void
1152vpn::dnsv4_ev (io_watcher &w, short revents) 1161vpn::dnsv4_ev (ev::io &w, int revents)
1153{ 1162{
1154 if (revents & EVENT_READ) 1163 if (revents & EV_READ)
1155 { 1164 {
1156 dns_packet *pkt = new dns_packet; 1165 dns_packet *pkt = new dns_packet;
1157 struct sockaddr_in sa; 1166 struct sockaddr_in sa;
1158 socklen_t sa_len = sizeof (sa); 1167 socklen_t sa_len = sizeof (sa);
1159 1168
… …
1175} 1184}
1176 1185
1177bool 1186bool
1178vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1187vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1179{ 1188{
1180 int client = ntohs (si.port); 1189 int client = ntohl (si.host);
1181 1190
1182 assert (0 < client && client <= conns.size ()); 1191 assert (0 < client && client <= conns.size ());
1183 1192
1184 connection *c = conns [client - 1]; 1193 connection *c = conns [client - 1];
1185 1194
1186 if (!c->dns) 1195 if (!c->dns)
1187 c->dns = new dns_connection (c); 1196 c->dns = new dns_connection (c);
1188 1197
1189 if (!c->dns->snddq.put (pkt)) 1198 if (c->dns->snddq.put (pkt))
1190 return false;
1191
1192 c->dns->tw.trigger (); 1199 c->dns->tw ();
1193 1200
1201 // always return true even if the buffer overflows
1194 return true; 1202 return true;
1195} 1203}
1196 1204
1197void 1205void
1198connection::dnsv4_reset_connection () 1206connection::dnsv4_reset_connection ()
… …
1201} 1209}
1202 1210
1203#define NEXT(w) do { if (next > (w)) next = w; } while (0) 1211#define NEXT(w) do { if (next > (w)) next = w; } while (0)
1204 1212
1205void 1213void
1206dns_connection::time_cb (time_watcher &w) 1214dns_connection::time_cb (ev::timer &w, int revents)
1207{ 1215{
1208 // servers have to be polled 1216 // servers have to be polled
1209 if (THISNODE->dns_port) 1217 if (THISNODE->dns_port)
1210 return; 1218 return;
1211 1219
1212 // check for timeouts and (re)transmit 1220 // check for timeouts and (re)transmit
1213 tstamp next = NOW + poll_interval; 1221 tstamp next = ev::now () + poll_interval;
1214 dns_snd *send = 0; 1222 dns_snd *send = 0;
1215 1223
1216 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin (); 1224 for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
1217 i != vpn->dns_sndpq.end (); 1225 i != vpn->dns_sndpq.end ();
1218 ++i) 1226 ++i)
1219 { 1227 {
1220 dns_snd *r = *i; 1228 dns_snd *r = *i;
1221 1229
1222 if (r->timeout <= NOW) 1230 if (r->timeout <= ev::ev_now ())
1223 { 1231 {
1224 if (!send) 1232 if (!send)
1225 { 1233 {
1226 send = r; 1234 send = r;
1227 1235
1228 r->retry++; 1236 r->retry++;
1229 r->timeout = NOW + (r->retry * min_latency * 8.); 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
1230 1239
1231 // the following code changes the query section a bit, forcing 1240 // the following code changes the query section a bit, forcing
1232 // the forwarder to generate a new request 1241 // the forwarder to generate a new request
1233 if (r->stdhdr) 1242 if (r->stdhdr)
1234 {
1235 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1236 //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);
1237 }
1238 } 1244 }
1239 } 1245 }
1240 else 1246 else
1241 NEXT (r->timeout); 1247 NEXT (r->timeout);
1242 } 1248 }
… …
1253 1259
1254 cfg.reset (THISNODE->id); 1260 cfg.reset (THISNODE->id);
1255 send->gen_syn_req (); 1261 send->gen_syn_req ();
1256 } 1262 }
1257 } 1263 }
1258 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1264 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1259 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1265 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1260 { 1266 {
1261 if (last_sent + send_interval <= NOW) 1267 if (last_sent + send_interval <= ev::ev_now ())
1262 { 1268 {
1263 //printf ("sending data request etc.\n"); //D 1269 //printf ("sending data request etc.\n"); //D
1264 if (!snddq.empty () || last_received + 1. > NOW) 1270 if (!snddq.empty () || last_received + 1. > ev::ev_now ())
1265 { 1271 {
1266 poll_interval = send_interval; 1272 poll_interval = send_interval;
1267 NEXT (NOW + send_interval); 1273 NEXT (ev::ev_now () + send_interval);
1268 } 1274 }
1269 1275
1270 send = new dns_snd (this); 1276 send = new dns_snd (this);
1271 send->gen_stream_req (sndseq, snddq); 1277 send->gen_stream_req (sndseq, snddq);
1272 send->timeout = NOW + min_latency * 8.; 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
1273 1280
1274 sndseq = (sndseq + 1) & SEQNO_MASK; 1281 sndseq = (sndseq + 1) & SEQNO_MASK;
1275 } 1282 }
1276 else 1283 else
1277 NEXT (last_sent + send_interval); 1284 NEXT (last_sent + send_interval);
… …
1281 vpn->dns_sndpq.push_back (send); 1288 vpn->dns_sndpq.push_back (send);
1282 } 1289 }
1283 1290
1284 if (send) 1291 if (send)
1285 { 1292 {
1286 last_sent = NOW; 1293 last_sent = ev::ev_now ();
1287 sendto (vpn->dnsv4_fd, 1294 sendto (vpn->dnsv4_fd,
1288 send->pkt->at (0), send->pkt->len, 0, 1295 send->pkt->at (0), send->pkt->len, 0,
1289 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1296 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1290 } 1297 }
1291 1298
1292 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)",
1293 poll_interval, send_interval, next - NOW, 1300 poll_interval, send_interval, next - ev::ev_now (),
1294 vpn->dns_sndpq.size (), snddq.size (), 1301 vpn->dns_sndpq.size (), snddq.size (),
1295 rcvpq.size ()); 1302 rcvpq.size ());
1296 1303
1297 // 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
1298 if (next < NOW + 0.001) 1305 // doesn't seem to happen anymore
1299 next = NOW + 0.1; 1306 if (next < ev::ev_now () + 0.001)
1307 next = ev::ev_now () + 0.1;
1300 1308
1301 w.start (next); 1309 w.start (next - ev::ev_now ());
1302} 1310}
1303 1311
1304#endif 1312#endif
1305 1313

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