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/cvs/gvpe/src/vpn_dns.C
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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.27 by pcg, Sat Mar 12 18:10:40 2005 UTC vs.
Revision 1.39 by pcg, Tue Apr 26 00:55:56 2005 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
… …
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 2. // optimistic? 59#define MAX_SEND_INTERVAL 2. // optimistic?
58 60
59#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
60#define MAX_OUTSTANDING 40 // max. outstanding requests
61#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog 61#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 62#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
63 63
64#define MAX_DOMAIN_SIZE 200 // 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
65// 240 leaves about 4 bytes of server reply data 65// 240 leaves about 4 bytes of server reply data
66// every two request bytes less give room for one reply byte 66// every request byte less give room for two reply bytes
67 67
68#define SEQNO_MASK 0x3fff 68#define SEQNO_MASK 0x3fff
69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
70 70
71#define MAX_LBL_SIZE 63 71#define MAX_LBL_SIZE 63
… …
424 u16 max_size; 424 u16 max_size;
425 u8 seq_cdc; 425 u8 seq_cdc;
426 u8 req_cdc; 426 u8 req_cdc;
427 427
428 u8 rep_cdc; 428 u8 rep_cdc;
429 u8 delay; // time in 0.01s units that the server may delay replying packets
429 u8 r2, r3, r4; 430 u8 r3, r4;
430 431
431 u8 r5, r6, r7, r8; 432 u8 r5, r6, r7, r8;
432 433
433 void reset (int clientid); 434 void reset (int clientid);
434 bool valid (); 435 bool valid ();
… …
452 req_cdc = 62; 453 req_cdc = 62;
453 rep_cdc = 0; 454 rep_cdc = 0;
454 max_size = htons (MAX_PKT_SIZE); 455 max_size = htons (MAX_PKT_SIZE);
455 client = htons (clientid); 456 client = htons (clientid);
456 uid = next_uid++; 457 uid = next_uid++;
458 delay = 0;
457 459
458 r2 = r3 = r4 = 0; 460 r3 = r4 = 0;
459 r4 = r5 = r6 = r7 = 0; 461 r4 = r5 = r6 = r7 = 0;
460} 462}
461 463
462bool dns_cfg::valid () 464bool dns_cfg::valid ()
463{ 465{
… …
552 double min_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 min_latency = INITIAL_TIMEOUT; 738 min_latency = INITIAL_TIMEOUT;
737} 739}
738 740
739dns_connection::~dns_connection () 741dns_connection::~dns_connection ()
… …
790 } 792 }
791 793
792 while (vpn_packet *pkt = rcvdq.get ()) 794 while (vpn_packet *pkt = rcvdq.get ())
793 { 795 {
794 sockinfo si; 796 sockinfo si;
795 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;
796 798
797 vpn->recv_vpn_packet (pkt, si); 799 vpn->recv_vpn_packet (pkt, si);
798 800
799 delete pkt; 801 delete pkt;
800 } 802 }
… …
854 if (0 < client && client <= conns.size ()) 856 if (0 < client && client <= conns.size ())
855 { 857 {
856 connection *c = conns [client - 1]; 858 connection *c = conns [client - 1];
857 dns_connection *dns = c->dns; 859 dns_connection *dns = c->dns;
858 dns_rcv *rcv; 860 dns_rcv *rcv;
859 bool in_seq;
860 861
861 if (dns) 862 if (dns)
862 { 863 {
863 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 (); )
864 if (SEQNO_EQ ((*i)->seqno, seqno)) 865 if (SEQNO_EQ ((*i)->seqno, seqno))
… …
875 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);
876 877
877 goto duplicate_request; 878 goto duplicate_request;
878 } 879 }
879 880
880 in_seq = dns->rcvseq == seqno;
881
882 // new packet, queue 881 // new packet, queue
883 rcv = new dns_rcv (seqno, data, datalen); 882 rcv = new dns_rcv (seqno, data, datalen);
884 dns->receive_rep (rcv); 883 dns->receive_rep (rcv);
885 } 884 }
886 885
… …
903 dlen -= qlen; 902 dlen -= qlen;
904 903
905 // only put data into in-order sequence packets, if 904 // only put data into in-order sequence packets, if
906 // we receive out-of-order packets we generate empty 905 // we receive out-of-order packets we generate empty
907 // replies 906 // replies
908 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)
909 { 909 {
910 dns->repseq = seqno;
911
912 while (dlen > 1 && !dns->snddq.empty ())
913 {
910 int txtlen = dlen <= 255 ? dlen - 1 : 255; 914 int txtlen = dlen <= 255 ? dlen - 1 : 255;
911 915
912 if (txtlen > dns->snddq.size ()) 916 if (txtlen > dns->snddq.size ())
913 txtlen = dns->snddq.size (); 917 txtlen = dns->snddq.size ();
914 918
915 pkt[offs++] = txtlen; 919 pkt[offs++] = txtlen;
916 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 920 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
917 offs += txtlen; 921 offs += txtlen;
918 dns->snddq.remove (txtlen); 922 dns->snddq.remove (txtlen);
919 923
920 dlen -= txtlen + 1; 924 dlen -= txtlen + 1;
925 }
921 } 926 }
922 927
923 // avoid empty TXT rdata 928 // avoid completely empty TXT rdata
924 if (offs == rdlen_offs) 929 if (offs == rdlen_offs)
925 pkt[offs++] = 0; 930 pkt[offs++] = 0;
926 931
927 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 932 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
928 } 933 }
… …
1027 double latency = NOW - (*i)->sent; 1032 double latency = NOW - (*i)->sent;
1028 1033
1029 if (latency < dns->min_latency) 1034 if (latency < dns->min_latency)
1030 dns->min_latency = latency; 1035 dns->min_latency = latency;
1031 1036
1032 if (dns->send_interval > dns->min_latency * LATENCY_FACTOR) 1037 if (dns->send_interval > dns->min_latency * conf.dns_overlap_factor)
1033 dns->send_interval = dns->min_latency * LATENCY_FACTOR; 1038 dns->send_interval = dns->min_latency * conf.dns_overlap_factor;
1034 1039
1035 if (dns->send_interval < MIN_SEND_INTERVAL) 1040 if (dns->send_interval < conf.dns_send_interval)
1036 dns->send_interval = MIN_SEND_INTERVAL; 1041 dns->send_interval = conf.dns_send_interval;
1037 } 1042 }
1038 1043
1039 delete *i; 1044 delete *i;
1040 dns_sndpq.erase (i); 1045 dns_sndpq.erase (i);
1041 1046
… …
1174} 1179}
1175 1180
1176bool 1181bool
1177vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos) 1182vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
1178{ 1183{
1179 int client = ntohs (si.port); 1184 int client = ntohl (si.host);
1180 1185
1181 assert (0 < client && client <= conns.size ()); 1186 assert (0 < client && client <= conns.size ());
1182 1187
1183 connection *c = conns [client - 1]; 1188 connection *c = conns [client - 1];
1184 1189
1185 if (!c->dns) 1190 if (!c->dns)
1186 c->dns = new dns_connection (c); 1191 c->dns = new dns_connection (c);
1187 1192
1188 if (!c->dns->snddq.put (pkt)) 1193 if (c->dns->snddq.put (pkt))
1189 return false;
1190
1191 c->dns->tw.trigger (); 1194 c->dns->tw.trigger ();
1192 1195
1196 // always return true even if the buffer overflows
1193 return true; 1197 return true;
1194} 1198}
1195 1199
1196void 1200void
1197connection::dnsv4_reset_connection () 1201connection::dnsv4_reset_connection ()
… …
1223 if (!send) 1227 if (!send)
1224 { 1228 {
1225 send = r; 1229 send = r;
1226 1230
1227 r->retry++; 1231 r->retry++;
1228 r->timeout = NOW + (r->retry * min_latency * 8.); 1232 r->timeout = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
1229 1233
1230 // the following code changes the query section a bit, forcing 1234 // the following code changes the query section a bit, forcing
1231 // the forwarder to generate a new request 1235 // the forwarder to generate a new request
1232 if (r->stdhdr) 1236 if (r->stdhdr)
1233 { 1237 {
… …
1238 } 1242 }
1239 else 1243 else
1240 NEXT (r->timeout); 1244 NEXT (r->timeout);
1241 } 1245 }
1242 1246
1243 if (send || (last_sent + send_interval <= NOW))
1244 {
1245 if (!send) 1247 if (!send)
1248 {
1249 // generate a new packet, if wise
1250
1251 if (!established)
1246 { 1252 {
1247 // generate a new packet, if wise 1253 if (vpn->dns_sndpq.empty ())
1248
1249 if (!established)
1250 { 1254 {
1251 if (vpn->dns_sndpq.empty ())
1252 {
1253 send = new dns_snd (this); 1255 send = new dns_snd (this);
1254 1256
1255 cfg.reset (THISNODE->id); 1257 cfg.reset (THISNODE->id);
1256 send->gen_syn_req (); 1258 send->gen_syn_req ();
1257 }
1258 } 1259 }
1259 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1260 }
1261 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1260 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1262 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1263 {
1264 if (last_sent + send_interval <= NOW)
1261 { 1265 {
1262 //printf ("sending data request etc.\n"); //D 1266 //printf ("sending data request etc.\n"); //D
1263 if (!snddq.empty () || last_received + 1. > NOW) 1267 if (!snddq.empty () || last_received + 1. > NOW)
1264 { 1268 {
1265 poll_interval = send_interval; 1269 poll_interval = send_interval;
1266 NEXT (NOW + send_interval); 1270 NEXT (NOW + send_interval);
1267 } 1271 }
1268 1272
1269 send = new dns_snd (this); 1273 send = new dns_snd (this);
1270 send->gen_stream_req (sndseq, snddq); 1274 send->gen_stream_req (sndseq, snddq);
1271 send->timeout = NOW + min_latency * 8.; 1275 send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1272 1276
1273 sndseq = (sndseq + 1) & SEQNO_MASK; 1277 sndseq = (sndseq + 1) & SEQNO_MASK;
1274 } 1278 }
1275 1279 else
1276 if (send && !send->retry) 1280 NEXT (last_sent + send_interval);
1277 vpn->dns_sndpq.push_back (send);
1278 } 1281 }
1279 1282
1280 if (send) 1283 if (send)
1281 { 1284 vpn->dns_sndpq.push_back (send);
1285 }
1286
1287 if (send)
1288 {
1282 last_sent = NOW; 1289 last_sent = NOW;
1283 sendto (vpn->dnsv4_fd, 1290 sendto (vpn->dnsv4_fd,
1284 send->pkt->at (0), send->pkt->len, 0, 1291 send->pkt->at (0), send->pkt->len, 0,
1285 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ()); 1292 vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
1286 }
1287 } 1293 }
1288 else
1289 NEXT (last_sent + send_interval);
1290 1294
1291 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)", 1295 slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
1292 poll_interval, send_interval, next - NOW, 1296 poll_interval, send_interval, next - NOW,
1293 vpn->dns_sndpq.size (), snddq.size (), 1297 vpn->dns_sndpq.size (), snddq.size (),
1294 rcvpq.size ()); 1298 rcvpq.size ());
1295 1299
1296 // 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
1297 if (next < NOW + 0.0001) 1302 if (next < NOW + 0.001)
1298 next = NOW + 0.1; 1303 next = NOW + 0.1;
1299 1304
1300 w.start (next); 1305 w.start (next);
1301} 1306}
1302 1307

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