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/cvs/gvpe/src/vpn_dns.C
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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.33 by pcg, Tue Mar 15 19:23:33 2005 UTC vs.
Revision 1.41 by pcg, Wed Nov 22 21:26:41 2006 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 8.
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 220 // 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
69#define SEQNO_MASK 0x3fff 68#define SEQNO_MASK 0x3fff
70#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) ) 69#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
… …
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
… …
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)
… …
1033 double latency = NOW - (*i)->sent; 1037 double latency = 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
… …
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 = NOW + (r->retry * min_latency * conf.dns_timeout_factor);
1234 printf ("TO %d %f\n", r->retry, r->timeout - NOW);//D 1238 //printf ("RETRY %x (%d, %f)\n", r->seqno, r->retry, r->timeout - NOW);//D
1235 1239
1236 // the following code changes the query section a bit, forcing 1240 // the following code changes the query section a bit, forcing
1237 // the forwarder to generate a new request 1241 // the forwarder to generate a new request
1238 if (r->stdhdr) 1242 if (r->stdhdr)
1239 {
1240 //printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
1241 //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);
1242 }
1243 } 1244 }
1244 } 1245 }
1245 else 1246 else
1246 NEXT (r->timeout); 1247 NEXT (r->timeout);
1247 } 1248 }
… …
1258 1259
1259 cfg.reset (THISNODE->id); 1260 cfg.reset (THISNODE->id);
1260 send->gen_syn_req (); 1261 send->gen_syn_req ();
1261 } 1262 }
1262 } 1263 }
1263 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1264 else if (vpn->dns_sndpq.size () < conf.dns_max_outstanding
1264 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1))) 1265 && !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
1265 { 1266 {
1266 if (last_sent + send_interval <= NOW) 1267 if (last_sent + send_interval <= NOW)
1267 { 1268 {
1268 //printf ("sending data request etc.\n"); //D 1269 //printf ("sending data request etc.\n"); //D
… …
1272 NEXT (NOW + send_interval); 1273 NEXT (NOW + send_interval);
1273 } 1274 }
1274 1275
1275 send = new dns_snd (this); 1276 send = new dns_snd (this);
1276 send->gen_stream_req (sndseq, snddq); 1277 send->gen_stream_req (sndseq, snddq);
1277 send->timeout = NOW + min_latency * TIMEOUT_FACTOR; 1278 send->timeout = NOW + min_latency * conf.dns_timeout_factor;
1279 //printf ("SEND %x (%f)\n", send->seqno, send->timeout - NOW, min_latency, conf.dns_timeout_factor);//D
1278 1280
1279 sndseq = (sndseq + 1) & SEQNO_MASK; 1281 sndseq = (sndseq + 1) & SEQNO_MASK;
1280 } 1282 }
1281 else 1283 else
1282 NEXT (last_sent + send_interval); 1284 NEXT (last_sent + send_interval);
… …
1298 poll_interval, send_interval, next - NOW, 1300 poll_interval, send_interval, next - NOW,
1299 vpn->dns_sndpq.size (), snddq.size (), 1301 vpn->dns_sndpq.size (), snddq.size (),
1300 rcvpq.size ()); 1302 rcvpq.size ());
1301 1303
1302 // TODO: no idea when this happens, but when next < NOW, we have a problem 1304 // TODO: no idea when this happens, but when next < NOW, we have a problem
1305 // doesn't seem to happen anymore
1303 if (next < NOW + 0.001) 1306 if (next < NOW + 0.001)
1304 next = NOW + 0.1; 1307 next = NOW + 0.1;
1305 1308
1306 w.start (next); 1309 w.start (next);
1307} 1310}

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