src/dns.cpp

   1 /*
   2 dns.cpp - based on the dns library Copyright (C) 2002 Ian Gulliver
   3
   4 This program is free software; you can redistribute it and/or modify
   5 it under the terms of version 2 of the GNU General Public License as
   6 published by the Free Software Foundation.
   7
   8 This program is distributed in the hope that it will be useful,
   9 but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 GNU General Public License for more details.
  12
  13 You should have received a copy of the GNU General Public License
  14 along with this program; if not, write to the Free Software
  15 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16 */
  17
  18 #define _DNS_C
  19
  20 #include <string>
  21 #include <stdlib.h>
  22 #include <time.h>
  23 #include <sys/types.h>
  24 #include <sys/socket.h>
  25 #include <sys/time.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <stdio.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <poll.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netinet/in.h>
  35 #include <arpa/inet.h>
  36 #include "dns.h"
  37
  38 extern int statsAccept,statsRefused,statsUnknown,statsCollisions,statsDns,statsDnsGood,statsDnsBad,statsConnects,statsSent,statsRecv;
  39
  40 #define max(a,b) (a > b ? a : b)
  41 #define DNS_MAX              8                    /* max number of nameservers used */
  42 #define DNS_CONFIG_FBCK     "/etc/resolv.conf"    /* fallback config file */
  43 #define DNS_PORT            53                    /* DNS well known port */
  44 #define DNS_QRY_A            1                    /* name to IP address */
  45 #define DNS_QRY_AAAA        28                    /* name to IP6 address */
  46 #define DNS_QRY_PTR         12                    /* IP address to name */
  47 #define DNS_QRY_MX          15                    /* name to MX */
  48 #define DNS_QRY_TXT         16                    /* name to TXT */
  49 #define DNS_QRY_CNAME       5
  50
  51 #define DNS_ALIGN (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long))
  52 #define DNS_TRIES 3
  53 #define RESULTSIZE 1024
  54 #define min(a,b) (a < b ? a : b)
  55
  56 static struct in_addr servers4[DNS_MAX]; /* up to DNS_MAX nameservers; populated by dns_init() */
  57 static int i4; /* actual count of nameservers; set by dns_init() */
  58
  59 static int initdone = 0; /* to ensure dns_init() only runs once (on the first call) */
  60 static int wantclose = 0;
  61 static int lastcreate = -1;
  62
  63 struct s_connection { /* open DNS query */
  64         struct s_connection *next; /* next in list */
  65         unsigned char id[2];
  66         unsigned int _class;
  67         unsigned int type;
  68         int want_list;
  69         int fd; /* file descriptor returned from sockets */
  70 };
  71
  72 struct s_rr_middle {
  73         unsigned int type;
  74         unsigned int _class;
  75         unsigned long ttl;
  76         unsigned int rdlength;
  77 };
  78
  79 #define DNS_POINTER_VALUE 0xc000
  80
  81 static s_connection *connection_head = NULL; /* linked list of open DNS queries; populated by dns_add_query(), decimated by dns_getresult_s() */
  82
  83 struct s_header { /* DNS query header */
  84         unsigned char id[2];
  85         unsigned int flags1;
  86 #define FLAGS1_MASK_QR 0x80
  87 #define FLAGS1_MASK_OPCODE 0x78 /* bitshift right 3 */
  88 #define FLAGS1_MASK_AA 0x04
  89 #define FLAGS1_MASK_TC 0x02
  90 #define FLAGS1_MASK_RD 0x01
  91         unsigned int flags2;
  92 #define FLAGS2_MASK_RA 0x80
  93 #define FLAGS2_MASK_Z  0x70
  94 #define FLAGS2_MASK_RCODE 0x0f
  95         unsigned int qdcount;
  96         unsigned int ancount;
  97         unsigned int nscount;
  98         unsigned int arcount;
  99         unsigned char payload[512]; /* DNS question, populated by dns_build_query_payload() */
 100 };
 101
 102 extern time_t TIME;
 103
 104 void *dns_align(void *inp) {
 105         char *p = (char*)inp;
 106         int offby = ((char *)p - (char *)0) % DNS_ALIGN;
 107         if (offby != 0)
 108                 return p + (DNS_ALIGN - offby);
 109         else
 110                 return p;
 111 }
 112
 113 /*
 114  * These little hacks are here to avoid alignment and type sizing issues completely by doing manual copies
 115  */
 116 void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
 117         rr->type = input[0] * 256 + input[1];
 118         rr->_class = input[2] * 256 + input[3];
 119         rr->ttl = input[4] * 16777216 + input[5] * 65536 + input[6] * 256 + input[7];
 120         rr->rdlength = input[8] * 256 + input[9];
 121 }
 122
 123 void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
 124         header->id[0] = input[0];
 125         header->id[1] = input[1];
 126         header->flags1 = input[2];
 127         header->flags2 = input[3];
 128         header->qdcount = input[4] * 256 + input[5];
 129         header->ancount = input[6] * 256 + input[7];
 130         header->nscount = input[8] * 256 + input[9];
 131         header->arcount = input[10] * 256 + input[11];
 132         memcpy(header->payload,&input[12],l);
 133 }
 134
 135 void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
 136         output[0] = header->id[0];
 137         output[1] = header->id[1];
 138         output[2] = header->flags1;
 139         output[3] = header->flags2;
 140         output[4] = header->qdcount / 256;
 141         output[5] = header->qdcount % 256;
 142         output[6] = header->ancount / 256;
 143         output[7] = header->ancount % 256;
 144         output[8] = header->nscount / 256;
 145         output[9] = header->nscount % 256;
 146         output[10] = header->arcount / 256;
 147         output[11] = header->arcount % 256;
 148         memcpy(&output[12],header->payload,l);
 149 }
 150
 151 void dns_close(int fd) { /* close query */
 152         if (fd == lastcreate) {
 153                 wantclose = 1;
 154                 return;
 155         }
 156         close(fd);
 157         return;
 158 }
 159
 160 void DNS::dns_init() { /* on first call only: populates servers4 struct with up to DNS_MAX nameserver IP addresses from /etc/resolv.conf */
 161         FILE *f;
 162         int i;
 163         in_addr addr4;
 164         char buf[1024];
 165         if (initdone == 1)
 166                 return;
 167         i4 = 0;
 168
 169         initdone = 1;
 170         srand((unsigned int) TIME);
 171         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 172         f = fopen(DNS_CONFIG_FBCK,"r");
 173         if (f == NULL)
 174                 return;
 175         while (fgets(buf,1024,f) != NULL) {
 176                 if (strncmp(buf,"nameserver",10) == 0) {
 177                         i = 10;
 178                         while (buf[i] == ' ' || buf[i] == '\t')
 179                                 i++;
 180                         if (i4 < DNS_MAX) {
 181                                 if (dns_aton4_s(&buf[i],&addr4) != NULL)
 182                                         memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 183                         }
 184                 }
 185         }
 186         fclose(f);
 187 }
 188
 189 void DNS::dns_init_2(const char* dnsserver)
 190 {
 191         in_addr addr4;
 192         i4 = 0;
 193         srand((unsigned int) TIME);
 194         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 195         if (dns_aton4_s(dnsserver,&addr4) != NULL)
 196             memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 197 }
 198
 199
 200 static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
 201 {
 202         int i;
 203         sockaddr_in addr4;
 204         unsigned char payload[sizeof(s_header)];
 205
 206         dns_empty_header(payload,h,l);
 207
 208
 209         i = 0;
 210
 211         /* otherwise send via standard ipv4 boringness */
 212         memset(&addr4,0,sizeof(addr4));
 213         memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
 214         addr4.sin_family = AF_INET;
 215         addr4.sin_port = htons(DNS_PORT);
 216         if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
 217         {
 218                 return -1;
 219         }
 220
 221         return 0;
 222 }
 223
 224 static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
 225         s_connection * s;
 226
 227         s = new s_connection;
 228
 229         /* set header flags */
 230         h->id[0] = s->id[0] = rand() % 255; /* verified by dns_getresult_s() */
 231         h->id[1] = s->id[1] = rand() % 255;
 232         h->flags1 = 0 | FLAGS1_MASK_RD;
 233         h->flags2 = 0;
 234         h->qdcount = 1;
 235         h->ancount = 0;
 236         h->nscount = 0;
 237         h->arcount = 0;
 238
 239         /* turn off want_list by default */
 240         s->want_list = 0;
 241
 242         /* try to create ipv6 or ipv4 socket */
 243                 s->fd = socket(PF_INET, SOCK_DGRAM, 0);
 244                 if (s->fd != -1) {
 245                         if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
 246                                 close(s->fd);
 247                                 s->fd = -1;
 248                         }
 249                 }
 250                 if (s->fd != -1) {
 251                         sockaddr_in addr;
 252                         memset(&addr,0,sizeof(addr));
 253                         addr.sin_family = AF_INET;
 254                         addr.sin_port = 0;
 255                         addr.sin_addr.s_addr = INADDR_ANY;
 256                         if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
 257                                 close(s->fd);
 258                                 s->fd = -1;
 259                         }
 260                 }
 261                 if (s->fd == -1) {
 262                         delete s;
 263                         return NULL;
 264                 }
 265         /* create new connection object, add to linked list */
 266         s->next = connection_head;
 267         connection_head = s;
 268
 269         if (wantclose == 1) {
 270                 close(lastcreate);
 271                 wantclose = 0;
 272         }
 273         lastcreate = s->fd;
 274         return s;
 275 }
 276
 277 static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
 278         short payloadpos;
 279         const char * tempchr, * tempchr2;
 280         unsigned short l;
 281
 282         payloadpos = 0;
 283         tempchr2 = name;
 284
 285         /* split name up into labels, create query */
 286         while ((tempchr = strchr(tempchr2,'.')) != NULL) {
 287                 l = tempchr - tempchr2;
 288                 if (payloadpos + l + 1 > 507)
 289                         return -1;
 290                 payload[payloadpos++] = l;
 291                 memcpy(&payload[payloadpos],tempchr2,l);
 292                 payloadpos += l;
 293                 tempchr2 = &tempchr[1];
 294         }
 295         l = strlen(tempchr2);
 296         if (l) {
 297                 if (payloadpos + l + 2 > 507)
 298                         return -1;
 299                 payload[payloadpos++] = l;
 300                 memcpy(&payload[payloadpos],tempchr2,l);
 301                 payloadpos += l;
 302                 payload[payloadpos++] = '\0';
 303         }
 304         if (payloadpos > 508)
 305                 return -1;
 306         l = htons(rr);
 307         memcpy(&payload[payloadpos],&l,2);
 308         l = htons(_class);
 309         memcpy(&payload[payloadpos + 2],&l,2);
 310         return payloadpos + 4;
 311 }
 312
 313 in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
 314         static in_addr ip;
 315         return dns_aton4_s(ipstring,&ip);
 316 }
 317
 318 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
 319         in_addr* ip;
 320         ip = new in_addr;
 321         if(dns_aton4_s(ipstring,ip) == NULL) {
 322                 delete ip;
 323                 return NULL;
 324         }
 325         return ip;
 326 }
 327
 328 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
 329         inet_aton(ipstring,ip);
 330         return ip;
 331 }
 332
 333 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 334         s_header h;
 335         s_connection *s;
 336         int l;
 337
 338         dns_init();
 339
 340
 341         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 342         if (l == -1)
 343                 return -1;
 344         s = dns_add_query(&h);
 345         if (s == NULL)
 346                 return -1;
 347         s->_class = 1;
 348         s->type = DNS_QRY_A;
 349         if (dns_send_requests(&h,s,l) == -1)
 350                 return -1;
 351
 352         return s->fd;
 353 }
 354
 355 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 356         s_header h;
 357         s_connection *s;
 358         int l;
 359
 360         dns_init();
 361
 362
 363         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 364         if (l == -1)
 365                 return -1;
 366         s = dns_add_query(&h);
 367         if (s == NULL)
 368                 return -1;
 369         s->_class = 1;
 370         s->type = DNS_QRY_A;
 371         s->want_list = 1;
 372         if (dns_send_requests(&h,s,l) == -1)
 373                 return -1;
 374
 375         return s->fd;
 376 }
 377
 378 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
 379         char query[512];
 380         s_header h;
 381         s_connection * s;
 382         unsigned char *c;
 383         int l;
 384
 385         c = (unsigned char *)&ip->s_addr;
 386
 387         sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
 388
 389         l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
 390         if (l == -1)
 391                 return -1;
 392         s = dns_add_query(&h);
 393         if (s == NULL)
 394                 return -1;
 395         s->_class = 1;
 396         s->type = DNS_QRY_PTR;
 397         if (dns_send_requests(&h,s,l) == -1)
 398                 return -1;
 399
 400         return s->fd;
 401 }
 402
 403 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
 404         static char r[256];
 405         return dns_ntoa4_s(ip,r);
 406 }
 407
 408 char* DNS::dns_ntoa4_r(const in_addr *ip) { /* numeric to ascii (reentrant): convert 4part IP addr struct to new string */
 409         char *r;
 410         r = new char[256];
 411         return dns_ntoa4_s(ip,r);
 412 }
 413
 414 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
 415         unsigned char *m;
 416         m = (unsigned char *)&ip->s_addr;
 417         sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
 418         return r;
 419 }
 420
 421 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
 422         static char r[RESULTSIZE];
 423         return dns_getresult_s(cfd,r);
 424 }
 425
 426 char* DNS::dns_getresult_r(const int cfd) { /* retrieve result of DNS query (reentrant) */
 427         char *r;
 428         r = new char[RESULTSIZE];
 429         if(dns_getresult_s(cfd,r) == NULL) {
 430                 delete r;
 431                 return NULL;
 432         }
 433         return r;
 434 }
 435
 436 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
 437         s_header h;
 438         s_connection *c, *prev;
 439         int l,i,q,curanswer,o;
 440         s_rr_middle rr;
 441         unsigned char buffer[sizeof(s_header)];
 442         unsigned short p;
 443
 444         if (res)
 445         {
 446                 res[0] = 0;
 447         }
 448
 449         prev = NULL;
 450         c = connection_head;
 451         while (c != NULL) { /* find query in list of open queries */
 452                 if (c->fd == cfd)
 453                         break;
 454                 prev = c;
 455                 c = c->next;
 456         }
 457         if (c == NULL) {
 458                 return NULL; /* query not found */
 459         }
 460         /* query found-- pull from list: */
 461         if (prev != NULL)
 462                 prev->next = c->next;
 463         else
 464                 connection_head = c->next;
 465
 466         l = recv(c->fd,buffer,sizeof(s_header),0);
 467         dns_close(c->fd);
 468         if (l < 12) {
 469                 delete c;
 470                 return NULL;
 471         }
 472         dns_fill_header(&h,buffer,l - 12);
 473         if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
 474                 delete c;
 475                 return NULL; /* ID mismatch */
 476         }
 477         if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
 478                 delete c;
 479                 return NULL;
 480         }
 481         if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
 482                 delete c;
 483                 return NULL;
 484         }
 485         if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
 486                 delete c;
 487                 return NULL;
 488         }
 489         if (h.ancount < 1)  { /* no sense going on if we don't have any answers */
 490                 delete c;
 491                 return NULL;
 492         }
 493         /* skip queries */
 494         i = 0;
 495         q = 0;
 496         l -= 12;
 497         while (q < h.qdcount && i < l) {
 498                 if (h.payload[i] > 63) { /* pointer */
 499                         i += 6; /* skip pointer, _class and type */
 500                         q++;
 501                 } else { /* label */
 502                         if (h.payload[i] == 0) {
 503                                 q++;
 504                                 i += 5; /* skip nil, _class and type */
 505                         } else
 506                                 i += h.payload[i] + 1; /* skip length and label */
 507                 }
 508         }
 509         /* &h.payload[i] should now be the start of the first response */
 510         curanswer = 0;
 511         while (curanswer < h.ancount) {
 512                 q = 0;
 513                 while (q == 0 && i < l) {
 514                         if (h.payload[i] > 63) { /* pointer */
 515                                 i += 2; /* skip pointer */
 516                                 q = 1;
 517                         } else { /* label */
 518                                 if (h.payload[i] == 0) {
 519                                         i++;
 520                                         q = 1;
 521                                 } else
 522                                         i += h.payload[i] + 1; /* skip length and label */
 523                         }
 524                 }
 525                 if (l - i < 10) {
 526                         delete c;
 527                         return NULL;
 528                 }
 529                 dns_fill_rr(&rr,&h.payload[i]);
 530                 i += 10;
 531                 if (rr.type != c->type) {
 532                         curanswer++;
 533                         i += rr.rdlength;
 534                         continue;
 535                 }
 536                 if (rr._class != c->_class) {
 537                         curanswer++;
 538                         i += rr.rdlength;
 539                         continue;
 540                 }
 541                 break;
 542         }
 543         if (curanswer == h.ancount)
 544                 return NULL;
 545         if (i + rr.rdlength > l)
 546                 return NULL;
 547         if (rr.rdlength > 1023)
 548                 return NULL;
 549
 550         switch (rr.type) {
 551                 case DNS_QRY_PTR:
 552                         o = 0;
 553                         q = 0;
 554                         while (q == 0 && i < l && o + 256 < 1023) {
 555                                 if (h.payload[i] > 63) { /* pointer */
 556                                         memcpy(&p,&h.payload[i],2);
 557                                         i = ntohs(p) - DNS_POINTER_VALUE - 12;
 558                                 } else { /* label */
 559                                         if (h.payload[i] == 0)
 560                                                 q = 1;
 561                                         else {
 562                                                 res[o] = '\0';
 563                                                 if (o != 0)
 564                                                         res[o++] = '.';
 565                                                 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
 566                                                 o += h.payload[i];
 567                                                 i += h.payload[i] + 1;
 568                                         }
 569                                 }
 570                         }
 571                         res[o] = '\0';
 572                         break;
 573                 case DNS_QRY_A:
 574                         if (c->want_list) {
 575                                 dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
 576                                 while ((char *)alist - (char *)res < 700) {
 577                                         if (rr.type != DNS_QRY_A)
 578                                                 break;
 579                                         if (rr._class != 1)
 580                                                 break;
 581                                         if (rr.rdlength != 4) {
 582                                                 delete c;
 583                                                 return NULL;
 584                                         }
 585                                         memcpy(&alist->ip,&h.payload[i],4);
 586                                         if (++curanswer >= h.ancount)
 587                                                 break;
 588                                         i += rr.rdlength;
 589                                         {
 590                                                 /* skip next name */
 591                                                 q = 0;
 592                                                 while (q == 0 && i < l) {
 593                                                         if (h.payload[i] > 63) { /* pointer */
 594                                                                 i += 2; /* skip pointer */
 595                                                                 q = 1;
 596                                                         } else { /* label */
 597                                                                 if (h.payload[i] == 0) {
 598                                                                         i++;
 599                                                                         q = 1;
 600                                                                 } else
 601                                                                         i += h.payload[i] + 1; /* skip length and label */
 602                                                         }
 603                                                 }
 604                                         }
 605                                         if (l - i < 10) {
 606                                                 delete c;
 607                                                 return NULL;
 608                                         }
 609                                         dns_fill_rr(&rr,&h.payload[i]);
 610                                         i += 10;
 611                                         alist->next = (dns_ip4list *) dns_align(((char *) alist) + sizeof(dns_ip4list));
 612                                         alist = alist->next;
 613                                         alist->next = NULL;
 614                                 }
 615                                 alist->next = NULL;
 616                                 break;
 617                         }
 618                         goto defaultcase;
 619                         break;
 620                 default:
 621                 defaultcase:
 622                         memcpy(res,&h.payload[i],rr.rdlength);
 623                         res[rr.rdlength] = '\0';
 624                         break;
 625         }
 626         delete c;
 627         return res;
 628 }
 629
 630 DNS::DNS()
 631 {
 632         dns_init();
 633 }
 634
 635 DNS::DNS(std::string dnsserver)
 636 {
 637         dns_init_2(dnsserver.c_str());
 638 }
 639
 640 void DNS::SetNS(std::string dnsserver)
 641 {
 642         dns_init_2(dnsserver.c_str());
 643 }
 644
 645 DNS::~DNS()
 646 {
 647 }
 648
 649 bool DNS::ReverseLookup(std::string ip)
 650 {
 651         statsDns++;
 652         binip = dns_aton4(ip.c_str());
 653         if (binip == NULL) {
 654                 return false;
 655         }
 656
 657         this->fd = dns_getname4(binip);
 658         if (this->fd == -1)
 659         {
 660                 return false;
 661         }
 662         return true;
 663 }
 664
 665 bool DNS::ForwardLookup(std::string host)
 666 {
 667 }
 668
 669 bool DNS::HasResult()
 670 {
 671         pollfd polls;
 672         polls.fd = this->fd;
 673         polls.events = POLLIN;
 674         int ret = poll(&polls,1,1);
 675         return (ret > 0);
 676 }
 677
 678 int DNS::GetFD()
 679 {
 680         return this->fd;
 681 }
 682
 683 std::string DNS::GetResult()
 684 {
 685         result = dns_getresult(this->fd);
 686         if (result) {
 687                 statsDnsGood++;
 688                 dns_close(this->fd);
 689                 return result;
 690         } else {
 691                 statsDnsBad++;
 692                 return "";
 693         }
 694 }