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/cvs/gvpe/src/vpn_dns.C
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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.18 by pcg, Sat Mar 5 19:13:16 2005 UTC vs.
Revision 1.24 by pcg, Mon Mar 7 01:31:26 2005 UTC

… …
25 25
26// dns processing is EXTREMELY ugly. For obvious(?) reasons. 26// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27// it's a hack, use only in emergency situations please. 27// it's a hack, use only in emergency situations please.
28 28
29#include <cstring> 29#include <cstring>
30#include <cassert>
30 31
31#include <sys/types.h> 32#include <sys/types.h>
32#include <sys/socket.h> 33#include <sys/socket.h>
33#include <sys/wait.h> 34#include <sys/wait.h>
34#include <sys/uio.h> 35#include <sys/uio.h>
… …
264static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO"); 265static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
265 266
266///////////////////////////////////////////////////////////////////////////// 267/////////////////////////////////////////////////////////////////////////////
267 268
268#define HDRSIZE 6 269#define HDRSIZE 6
269 270
270inline void encode_header (char *data, int clientid, int seqno, int retry = 0) 271inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
271{ 272{
272 seqno &= SEQNO_MASK; 273 seqno &= SEQNO_MASK;
273 274
274 u8 hdr[3] = { 275 u8 hdr[3] = {
… …
408struct dns_cfg 409struct dns_cfg
409{ 410{
410 static int next_uid; 411 static int next_uid;
411 412
412 u8 id1, id2, id3, id4; 413 u8 id1, id2, id3, id4;
414
413 u8 version; 415 u8 version;
416 u8 flags;
414 u8 rrtype; 417 u8 rrtype;
415 u8 flags;
416 u8 def_ttl; 418 u8 def_ttl;
417 u8 rcv_cdc; 419
418 u8 snd_cdc;
419 u16 max_size;
420 u16 client; 420 u16 client;
421 u16 uid; // to make request unique 421 u16 uid; // to make request unique
422 422
423 u8 reserved[8]; 423 u16 max_size;
424 u8 seq_cdc;
425 u8 req_cdc;
426
427 u8 rep_cdc;
428 u8 r2, r3, r4;
429
430 u8 r5, r6, r7, r8;
424 431
425 void reset (int clientid); 432 void reset (int clientid);
426 bool valid (); 433 bool valid ();
427}; 434};
428 435
… …
437 444
438 version = 1; 445 version = 1;
439 446
440 rrtype = RR_TYPE_TXT; 447 rrtype = RR_TYPE_TXT;
441 flags = 0; 448 flags = 0;
442 def_ttl = 1; 449 def_ttl = 0;
450 seq_cdc = 26;
451 req_cdc = 62;
443 rcv_cdc = 0; 452 rep_cdc = 0;
444 snd_cdc = 62;
445 max_size = ntohs (MAX_PKT_SIZE); 453 max_size = ntohs (MAX_PKT_SIZE);
446 client = ntohs (clientid); 454 client = ntohs (clientid);
447 uid = next_uid++; 455 uid = next_uid++;
448 456
449 memset (reserved, 0, 8); 457 r2 = r3 = r4 = 0;
458 r4 = r5 = r6 = r7 = 0;
450} 459}
451 460
452bool dns_cfg::valid () 461bool dns_cfg::valid ()
453{ 462{
454 return id1 == 'G' 463 return id1 == 'G'
455 && id2 == 'V' 464 && id2 == 'V'
456 && id3 == 'P' 465 && id3 == 'P'
457 && id4 == 'E' 466 && id4 == 'E'
467 && seq_cdc == 26
468 && req_cdc == 62
469 && rep_cdc == 0
458 && version == 1 470 && version == 1
459 && flags == 0
460 && rcv_cdc == 0
461 && snd_cdc == 62
462 && max_size == ntohs (MAX_PKT_SIZE); 471 && max_size == ntohs (MAX_PKT_SIZE);
463} 472}
464 473
465struct dns_packet : net_packet 474struct dns_packet : net_packet
466{ 475{
467 u16 id; 476 u16 id;
468 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4 477 u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
469 u16 qdcount, ancount, nscount, arcount; 478 u16 qdcount, ancount, nscount, arcount;
470 479
471 u8 data[MAXSIZE - 6 * 2]; 480 u8 data [MAXSIZE - 6 * 2];
472 481
473 int decode_label (char *data, int size, int &offs); 482 int decode_label (char *data, int size, int &offs);
474}; 483};
475 484
476int dns_packet::decode_label (char *data, int size, int &offs) 485int dns_packet::decode_label (char *data, int size, int &offs)
… …
622 631
623 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 632 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
624 pkt->qdcount = htons (1); 633 pkt->qdcount = htons (1);
625 634
626 int offs = 6*2; 635 int offs = 6*2;
627 int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2); 636 int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
628 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well, 637 // MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
629 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra 638 // so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
630 639
631 char enc[256], *encp = enc; 640 char enc[256], *encp = enc;
632 encode_header (enc, THISNODE->id, seqno); 641 encode_header (enc, THISNODE->id, seqno);
… …
650 encp += lbllen; 659 encp += lbllen;
651 660
652 enclen -= lbllen; 661 enclen -= lbllen;
653 } 662 }
654 663
655 append_domain (*pkt, offs, THISNODE->domain); 664 append_domain (*pkt, offs, dns->c->conf->domain);
656 665
657 (*pkt)[offs++] = 0; 666 (*pkt)[offs++] = 0;
658 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY; 667 (*pkt)[offs++] = RR_TYPE_ANY >> 8; (*pkt)[offs++] = RR_TYPE_ANY;
659 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 668 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
660 669
… …
663 672
664void dns_snd::gen_syn_req () 673void dns_snd::gen_syn_req ()
665{ 674{
666 timeout = NOW + INITIAL_SYN_TIMEOUT; 675 timeout = NOW + INITIAL_SYN_TIMEOUT;
667 676
668 printf ("send syn\n");//D
669
670 pkt->flags = htons (DEFAULT_CLIENT_FLAGS); 677 pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
671 pkt->qdcount = htons (1); 678 pkt->qdcount = htons (1);
672 679
673 int offs = 6 * 2; 680 int offs = 6 * 2;
674 681
… …
676 683
677 assert (elen <= MAX_LBL_SIZE); 684 assert (elen <= MAX_LBL_SIZE);
678 685
679 (*pkt)[offs] = elen; 686 (*pkt)[offs] = elen;
680 offs += elen + 1; 687 offs += elen + 1;
681 append_domain (*pkt, offs, THISNODE->domain); 688 append_domain (*pkt, offs, dns->c->conf->domain);
682 689
683 (*pkt)[offs++] = 0; 690 (*pkt)[offs++] = 0;
684 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A; 691 (*pkt)[offs++] = RR_TYPE_A >> 8; (*pkt)[offs++] = RR_TYPE_A;
685 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN; 692 (*pkt)[offs++] = RR_CLASS_IN >> 8; (*pkt)[offs++] = RR_CLASS_IN;
686 693
… …
806 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 813 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
807 814
808 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK)) 815 if (0 == (flags & (FLAG_RESPONSE | FLAG_OP_MASK))
809 && pkt.qdcount == htons (1)) 816 && pkt.qdcount == htons (1))
810 { 817 {
811 char qname[MAXSIZE]; 818 char qname [MAXSIZE];
812 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs); 819 int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
813 820
814 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++]; 821 u16 qtype = pkt [offs++] << 8; qtype |= pkt [offs++];
815 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++]; 822 u16 qclass = pkt [offs++] << 8; qclass |= pkt [offs++];
816 823
… …
823 830
824 int dlen = strlen (THISNODE->domain); 831 int dlen = strlen (THISNODE->domain);
825 832
826 if (qclass == RR_CLASS_IN 833 if (qclass == RR_CLASS_IN
827 && qlen > dlen + 1 834 && qlen > dlen + 1
828 && !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen)) 835 && !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
829 { 836 {
830 // now generate reply 837 // now generate reply
831 pkt.ancount = htons (1); // one answer RR 838 pkt.ancount = htons (1); // one answer RR
832 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK); 839 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_OK);
833 840
… …
874 // new packet, queue 881 // new packet, queue
875 rcv = new dns_rcv (seqno, data, datalen); 882 rcv = new dns_rcv (seqno, data, datalen);
876 dns->receive_rep (rcv); 883 dns->receive_rep (rcv);
877 } 884 }
878 885
886 {
879 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section 887 pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
880 888
881 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A; 889 int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
882 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type 890 pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
883 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 891 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
884 pkt [offs++] = 0; pkt [offs++] = 0; 892 pkt [offs++] = 0; pkt [offs++] = 0;
885 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL 893 pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
886 894
887 int rdlen_offs = offs += 2; 895 int rdlen_offs = offs += 2;
888 896
889 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs; 897 int dlen = (dns ? ntohs (dns->cfg.max_size) : MAX_PKT_SIZE) - offs;
890 // bind doesn't compress well, so reduce further by one label length 898 // bind doesn't compress well, so reduce further by one label length
891 dlen -= qlen; 899 dlen -= qlen;
892 900
893 if (dns) 901 if (dns)
894 { 902 {
895 // only put data into in-order sequence packets, if 903 // only put data into in-order sequence packets, if
896 // we receive out-of-order packets we generate empty 904 // we receive out-of-order packets we generate empty
897 // replies 905 // replies
898 while (dlen > 1 && !dns->snddq.empty () && in_seq) 906 while (dlen > 1 && !dns->snddq.empty () && in_seq)
899 { 907 {
900 int txtlen = dlen <= 255 ? dlen - 1 : 255; 908 int txtlen = dlen <= 255 ? dlen - 1 : 255;
901 909
902 if (txtlen > dns->snddq.size ()) 910 if (txtlen > dns->snddq.size ())
903 txtlen = dns->snddq.size (); 911 txtlen = dns->snddq.size ();
904 912
905 pkt[offs++] = txtlen; 913 pkt[offs++] = txtlen;
906 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen); 914 memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
907 offs += txtlen; 915 offs += txtlen;
908 dns->snddq.remove (txtlen); 916 dns->snddq.remove (txtlen);
909 917
910 dlen -= txtlen + 1; 918 dlen -= txtlen + 1;
911 } 919 }
912 920
913 // avoid empty TXT rdata 921 // avoid empty TXT rdata
914 if (offs == rdlen_offs) 922 if (offs == rdlen_offs)
915 pkt[offs++] = 0; 923 pkt[offs++] = 0;
916 924
917 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ()); 925 slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
918 } 926 }
919 else 927 else
920 { 928 {
921 // send RST 929 // send RST
922 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 930 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
923 pkt [offs++] = CMD_IP_RST; 931 pkt [offs++] = CMD_IP_RST;
924 } 932 }
925 933
926 int rdlen = offs - rdlen_offs; 934 int rdlen = offs - rdlen_offs;
927 935
928 pkt [rdlen_offs - 2] = rdlen >> 8; 936 pkt [rdlen_offs - 2] = rdlen >> 8;
929 pkt [rdlen_offs - 1] = rdlen; 937 pkt [rdlen_offs - 1] = rdlen;
930 938
931 if (dns) 939 if (dns)
932 { 940 {
933 // now update dns_rcv copy 941 // now update dns_rcv copy
934 rcv->pkt->len = offs; 942 rcv->pkt->len = offs;
935 memcpy (rcv->pkt->at (0), pkt.at (0), offs); 943 memcpy (rcv->pkt->at (0), pkt.at (0), offs);
936 } 944 }
945 }
937 946
938 duplicate_request: ; 947 duplicate_request: ;
939 } 948 }
940 else 949 else
941 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR); 950 pkt.flags = htons (DEFAULT_SERVER_FLAGS | FLAG_RCODE_FORMERR);
… …
953 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class 962 pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
954 pkt [offs++] = 0; pkt [offs++] = 0; 963 pkt [offs++] = 0; pkt [offs++] = 0;
955 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL 964 pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
956 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength 965 pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
957 966
958 slog (L_INFO, _("DNS: client %d tries to connect"), client); 967 slog (L_INFO, _("DNS: client %d connects"), client);
959 968
960 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3; 969 pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
961 pkt [offs++] = CMD_IP_REJ; 970 pkt [offs++] = CMD_IP_REJ;
962 971
963 if (0 < client && client <= conns.size ()) 972 if (0 < client && client <= conns.size ())
… …
1145 1154
1146 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len); 1155 pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
1147 1156
1148 if (pkt->len > 0) 1157 if (pkt->len > 0)
1149 { 1158 {
1150 if (THISNODE->dns_port) 1159 if (ntohs (pkt->flags) & FLAG_RESPONSE)
1160 dnsv4_client (*pkt);
1161 else
1151 { 1162 {
1152 dnsv4_server (*pkt); 1163 dnsv4_server (*pkt);
1153 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len); 1164 sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
1154 } 1165 }
1155 else
1156 dnsv4_client (*pkt);
1157 1166
1158 delete pkt; 1167 delete pkt;
1159 } 1168 }
1160 } 1169 }
1161} 1170}
… …
1237 { 1246 {
1238 if (vpn->dns_sndpq.empty ()) 1247 if (vpn->dns_sndpq.empty ())
1239 { 1248 {
1240 send = new dns_snd (this); 1249 send = new dns_snd (this);
1241 1250
1242 printf ("new conn %p %d\n", this, c->conf->id);//D
1243 cfg.reset (THISNODE->id); 1251 cfg.reset (THISNODE->id);
1244 send->gen_syn_req (); 1252 send->gen_syn_req ();
1245 } 1253 }
1246 } 1254 }
1247 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING 1255 else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING

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