src/dns.cpp

   1 /*
   2 dns.cpp - based on the firedns 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 using namespace std;
  21
  22 #include <string>
  23 #include <stdlib.h>
  24 #include <time.h>
  25 #include <sys/types.h>
  26 #include <sys/socket.h>
  27 #include <sys/time.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <stdio.h>
  31 #include <errno.h>
  32 #include <fcntl.h>
  33 #include <poll.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <netinet/in.h>
  37 #include <arpa/inet.h>
  38 #include "dns.h"
  39 #include "helperfuncs.h"
  40
  41 extern int statsAccept,statsRefused,statsUnknown,statsCollisions,statsDns,statsDnsGood,statsDnsBad,statsConnects,statsSent,statsRecv;
  42
  43 #define max(a,b) (a > b ? a : b)
  44 #define DNS_MAX              8                    /* max number of nameservers used */
  45 #define DNS_CONFIG_FBCK     "/etc/resolv.conf"    /* fallback config file */
  46 #define DNS_PORT            53                    /* DNS well known port */
  47 #define DNS_QRY_A            1                    /* name to IP address */
  48 #define DNS_QRY_AAAA        28                    /* name to IP6 address */
  49 #define DNS_QRY_PTR         12                    /* IP address to name */
  50 #define DNS_QRY_MX          15                    /* name to MX */
  51 #define DNS_QRY_TXT         16                    /* name to TXT */
  52 #define DNS_QRY_CNAME       5
  53
  54 #define DNS_ALIGN (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long))
  55 #define DNS_TRIES 3
  56 #define RESULTSIZE 1024
  57 #define min(a,b) (a < b ? a : b)
  58
  59 static struct in_addr servers4[DNS_MAX]; /* up to DNS_MAX nameservers; populated by dns_init() */
  60 static int i4; /* actual count of nameservers; set by dns_init() */
  61
  62 static int initdone = 0; /* to ensure dns_init() only runs once (on the first call) */
  63 static int wantclose = 0;
  64 static int lastcreate = -1;
  65
  66 struct s_connection { /* open DNS query */
  67         struct s_connection *next; /* next in list */
  68         unsigned char id[2];
  69         unsigned int _class;
  70         unsigned int type;
  71         int want_list;
  72         int fd; /* file descriptor returned from sockets */
  73 };
  74
  75 struct s_rr_middle {
  76         unsigned int type;
  77         unsigned int _class;
  78         unsigned long ttl;
  79         unsigned int rdlength;
  80 };
  81
  82 #define DNS_POINTER_VALUE 0xc000
  83
  84 static s_connection *connection_head = NULL; /* linked list of open DNS queries; populated by dns_add_query(), decimated by dns_getresult_s() */
  85
  86 struct s_header { /* DNS query header */
  87         unsigned char id[2];
  88         unsigned int flags1;
  89 #define FLAGS1_MASK_QR 0x80
  90 #define FLAGS1_MASK_OPCODE 0x78 /* bitshift right 3 */
  91 #define FLAGS1_MASK_AA 0x04
  92 #define FLAGS1_MASK_TC 0x02
  93 #define FLAGS1_MASK_RD 0x01
  94         unsigned int flags2;
  95 #define FLAGS2_MASK_RA 0x80
  96 #define FLAGS2_MASK_Z  0x70
  97 #define FLAGS2_MASK_RCODE 0x0f
  98         unsigned int qdcount;
  99         unsigned int ancount;
 100         unsigned int nscount;
 101         unsigned int arcount;
 102         unsigned char payload[512]; /* DNS question, populated by dns_build_query_payload() */
 103 };
 104
 105 extern time_t TIME;
 106
 107 void *dns_align(void *inp) {
 108         char *p = (char*)inp;
 109         int offby = ((char *)p - (char *)0) % DNS_ALIGN;
 110         if (offby != 0)
 111                 return p + (DNS_ALIGN - offby);
 112         else
 113                 return p;
 114 }
 115
 116 /*
 117  * These little hacks are here to avoid alignment and type sizing issues completely by doing manual copies
 118  */
 119 void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
 120         rr->type = input[0] * 256 + input[1];
 121         rr->_class = input[2] * 256 + input[3];
 122         rr->ttl = input[4] * 16777216 + input[5] * 65536 + input[6] * 256 + input[7];
 123         rr->rdlength = input[8] * 256 + input[9];
 124 }
 125
 126 void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
 127         header->id[0] = input[0];
 128         header->id[1] = input[1];
 129         header->flags1 = input[2];
 130         header->flags2 = input[3];
 131         header->qdcount = input[4] * 256 + input[5];
 132         header->ancount = input[6] * 256 + input[7];
 133         header->nscount = input[8] * 256 + input[9];
 134         header->arcount = input[10] * 256 + input[11];
 135         memcpy(header->payload,&input[12],l);
 136 }
 137
 138 void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
 139         output[0] = header->id[0];
 140         output[1] = header->id[1];
 141         output[2] = header->flags1;
 142         output[3] = header->flags2;
 143         output[4] = header->qdcount / 256;
 144         output[5] = header->qdcount % 256;
 145         output[6] = header->ancount / 256;
 146         output[7] = header->ancount % 256;
 147         output[8] = header->nscount / 256;
 148         output[9] = header->nscount % 256;
 149         output[10] = header->arcount / 256;
 150         output[11] = header->arcount % 256;
 151         memcpy(&output[12],header->payload,l);
 152 }
 153
 154 void dns_close(int fd) { /* close query */
 155         if (fd == lastcreate) {
 156                 wantclose = 1;
 157                 return;
 158         }
 159         close(fd);
 160         return;
 161 }
 162
 163 void DNS::dns_init() { /* on first call only: populates servers4 struct with up to DNS_MAX nameserver IP addresses from /etc/resolv.conf */
 164         FILE *f;
 165         int i;
 166         in_addr addr4;
 167         char buf[1024];
 168         if (initdone == 1)
 169                 return;
 170         i4 = 0;
 171
 172         initdone = 1;
 173         srand((unsigned int) TIME);
 174         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 175         f = fopen(DNS_CONFIG_FBCK,"r");
 176         if (f == NULL)
 177                 return;
 178         while (fgets(buf,1024,f) != NULL) {
 179                 if (strncmp(buf,"nameserver",10) == 0) {
 180                         i = 10;
 181                         while (buf[i] == ' ' || buf[i] == '\t')
 182                                 i++;
 183                         if (i4 < DNS_MAX) {
 184                                 if (dns_aton4_s(&buf[i],&addr4) != NULL)
 185                                         memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 186                         }
 187                 }
 188         }
 189         fclose(f);
 190 }
 191
 192 void DNS::dns_init_2(const char* dnsserver)
 193 {
 194         in_addr addr4;
 195         i4 = 0;
 196         srand((unsigned int) TIME);
 197         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 198         if (dns_aton4_s(dnsserver,&addr4) != NULL)
 199             memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 200 }
 201
 202
 203 static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
 204 {
 205         int i;
 206         sockaddr_in addr4;
 207         unsigned char payload[sizeof(s_header)];
 208
 209         dns_empty_header(payload,h,l);
 210
 211
 212         i = 0;
 213
 214         /* otherwise send via standard ipv4 boringness */
 215         memset(&addr4,0,sizeof(addr4));
 216         memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
 217         addr4.sin_family = AF_INET;
 218         addr4.sin_port = htons(DNS_PORT);
 219         if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
 220         {
 221                 return -1;
 222         }
 223
 224         return 0;
 225 }
 226
 227 static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
 228         s_connection * s;
 229
 230         s = new s_connection;
 231
 232         /* set header flags */
 233         h->id[0] = s->id[0] = rand() % 255; /* verified by dns_getresult_s() */
 234         h->id[1] = s->id[1] = rand() % 255;
 235         h->flags1 = 0 | FLAGS1_MASK_RD;
 236         h->flags2 = 0;
 237         h->qdcount = 1;
 238         h->ancount = 0;
 239         h->nscount = 0;
 240         h->arcount = 0;
 241
 242         /* turn off want_list by default */
 243         s->want_list = 0;
 244
 245         /* try to create ipv6 or ipv4 socket */
 246                 s->fd = socket(PF_INET, SOCK_DGRAM, 0);
 247                 if (s->fd != -1) {
 248                         if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
 249                                 close(s->fd);
 250                                 s->fd = -1;
 251                         }
 252                 }
 253                 if (s->fd != -1) {
 254                         sockaddr_in addr;
 255                         memset(&addr,0,sizeof(addr));
 256                         addr.sin_family = AF_INET;
 257                         addr.sin_port = 0;
 258                         addr.sin_addr.s_addr = INADDR_ANY;
 259                         if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
 260                                 close(s->fd);
 261                                 s->fd = -1;
 262                         }
 263                 }
 264                 if (s->fd == -1) {
 265                         delete s;
 266                         return NULL;
 267                 }
 268         /* create new connection object, add to linked list */
 269         s->next = connection_head;
 270         connection_head = s;
 271
 272         if (wantclose == 1) {
 273                 close(lastcreate);
 274                 wantclose = 0;
 275         }
 276         lastcreate = s->fd;
 277         return s;
 278 }
 279
 280 static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
 281         short payloadpos;
 282         const char * tempchr, * tempchr2;
 283         unsigned short l;
 284
 285         payloadpos = 0;
 286         tempchr2 = name;
 287
 288         /* split name up into labels, create query */
 289         while ((tempchr = strchr(tempchr2,'.')) != NULL) {
 290                 l = tempchr - tempchr2;
 291                 if (payloadpos + l + 1 > 507)
 292                         return -1;
 293                 payload[payloadpos++] = l;
 294                 memcpy(&payload[payloadpos],tempchr2,l);
 295                 payloadpos += l;
 296                 tempchr2 = &tempchr[1];
 297         }
 298         l = strlen(tempchr2);
 299         if (l) {
 300                 if (payloadpos + l + 2 > 507)
 301                         return -1;
 302                 payload[payloadpos++] = l;
 303                 memcpy(&payload[payloadpos],tempchr2,l);
 304                 payloadpos += l;
 305                 payload[payloadpos++] = '\0';
 306         }
 307         if (payloadpos > 508)
 308                 return -1;
 309         l = htons(rr);
 310         memcpy(&payload[payloadpos],&l,2);
 311         l = htons(_class);
 312         memcpy(&payload[payloadpos + 2],&l,2);
 313         return payloadpos + 4;
 314 }
 315
 316 in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
 317         static in_addr ip;
 318         return dns_aton4_s(ipstring,&ip);
 319 }
 320
 321 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
 322         in_addr* ip;
 323         ip = new in_addr;
 324         if(dns_aton4_s(ipstring,ip) == NULL) {
 325                 delete ip;
 326                 return NULL;
 327         }
 328         return ip;
 329 }
 330
 331 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
 332         inet_aton(ipstring,ip);
 333         return ip;
 334 }
 335
 336 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 337         s_header h;
 338         s_connection *s;
 339         int l;
 340
 341         dns_init();
 342
 343
 344         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 345         if (l == -1)
 346                 return -1;
 347         s = dns_add_query(&h);
 348         if (s == NULL)
 349                 return -1;
 350         s->_class = 1;
 351         s->type = DNS_QRY_A;
 352         if (dns_send_requests(&h,s,l) == -1)
 353                 return -1;
 354
 355         return s->fd;
 356 }
 357
 358 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 359         s_header h;
 360         s_connection *s;
 361         int l;
 362
 363         dns_init();
 364
 365
 366         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 367         if (l == -1)
 368                 return -1;
 369         s = dns_add_query(&h);
 370         if (s == NULL)
 371                 return -1;
 372         s->_class = 1;
 373         s->type = DNS_QRY_A;
 374         s->want_list = 1;
 375         if (dns_send_requests(&h,s,l) == -1)
 376                 return -1;
 377
 378         return s->fd;
 379 }
 380
 381 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
 382         char query[512];
 383         s_header h;
 384         s_connection * s;
 385         unsigned char *c;
 386         int l;
 387
 388         c = (unsigned char *)&ip->s_addr;
 389
 390         sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
 391
 392         l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
 393         if (l == -1)
 394                 return -1;
 395         s = dns_add_query(&h);
 396         if (s == NULL)
 397                 return -1;
 398         s->_class = 1;
 399         s->type = DNS_QRY_PTR;
 400         if (dns_send_requests(&h,s,l) == -1)
 401                 return -1;
 402
 403         return s->fd;
 404 }
 405
 406 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
 407         static char r[256];
 408         return dns_ntoa4_s(ip,r);
 409 }
 410
 411 char* DNS::dns_ntoa4_r(const in_addr *ip) { /* numeric to ascii (reentrant): convert 4part IP addr struct to new string */
 412         char *r;
 413         r = new char[256];
 414         return dns_ntoa4_s(ip,r);
 415 }
 416
 417 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
 418         unsigned char *m;
 419         m = (unsigned char *)&ip->s_addr;
 420         sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
 421         return r;
 422 }
 423
 424 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
 425         static char r[RESULTSIZE];
 426         return dns_getresult_s(cfd,r);
 427 }
 428
 429 char* DNS::dns_getresult_r(const int cfd) { /* retrieve result of DNS query (reentrant) */
 430         char *r;
 431         r = new char[RESULTSIZE];
 432         if(dns_getresult_s(cfd,r) == NULL) {
 433                 delete r;
 434                 return NULL;
 435         }
 436         return r;
 437 }
 438
 439 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
 440         s_header h;
 441         s_connection *c, *prev;
 442         int l,i,q,curanswer,o;
 443         s_rr_middle rr;
 444         unsigned char buffer[sizeof(s_header)];
 445         unsigned short p;
 446
 447         if (res)
 448         {
 449                 res[0] = 0;
 450         }
 451
 452         prev = NULL;
 453         c = connection_head;
 454         while (c != NULL) { /* find query in list of open queries */
 455                 if (c->fd == cfd)
 456                         break;
 457                 prev = c;
 458                 c = c->next;
 459         }
 460         if (c == NULL) {
 461                 return NULL; /* query not found */
 462         }
 463         /* query found-- pull from list: */
 464         if (prev != NULL)
 465                 prev->next = c->next;
 466         else
 467                 connection_head = c->next;
 468
 469         l = recv(c->fd,buffer,sizeof(s_header),0);
 470         dns_close(c->fd);
 471         if (l < 12) {
 472                 delete c;
 473                 return NULL;
 474         }
 475         dns_fill_header(&h,buffer,l - 12);
 476         if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
 477                 delete c;
 478                 return NULL; /* ID mismatch */
 479         }
 480         if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
 481                 delete c;
 482                 return NULL;
 483         }
 484         if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
 485                 delete c;
 486                 return NULL;
 487         }
 488         if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
 489                 delete c;
 490                 return NULL;
 491         }
 492         if (h.ancount < 1)  { /* no sense going on if we don't have any answers */
 493                 delete c;
 494                 return NULL;
 495         }
 496         /* skip queries */
 497         i = 0;
 498         q = 0;
 499         l -= 12;
 500         while ((unsigned)q < h.qdcount && i < l) {
 501                 if (h.payload[i] > 63) { /* pointer */
 502                         i += 6; /* skip pointer, _class and type */
 503                         q++;
 504                 } else { /* label */
 505                         if (h.payload[i] == 0) {
 506                                 q++;
 507                                 i += 5; /* skip nil, _class and type */
 508                         } else
 509                                 i += h.payload[i] + 1; /* skip length and label */
 510                 }
 511         }
 512         /* &h.payload[i] should now be the start of the first response */
 513         curanswer = 0;
 514         while ((unsigned)curanswer < h.ancount) {
 515                 q = 0;
 516                 while (q == 0 && i < l) {
 517                         if (h.payload[i] > 63) { /* pointer */
 518                                 i += 2; /* skip pointer */
 519                                 q = 1;
 520                         } else { /* label */
 521                                 if (h.payload[i] == 0) {
 522                                         i++;
 523                                         q = 1;
 524                                 } else
 525                                         i += h.payload[i] + 1; /* skip length and label */
 526                         }
 527                 }
 528                 if (l - i < 10) {
 529                         delete c;
 530                         return NULL;
 531                 }
 532                 dns_fill_rr(&rr,&h.payload[i]);
 533                 i += 10;
 534                 if (rr.type != c->type) {
 535                         curanswer++;
 536                         i += rr.rdlength;
 537                         continue;
 538                 }
 539                 if (rr._class != c->_class) {
 540                         curanswer++;
 541                         i += rr.rdlength;
 542                         continue;
 543                 }
 544                 break;
 545         }
 546         if ((unsigned)curanswer == h.ancount)
 547                 return NULL;
 548         if ((unsigned)i + rr.rdlength > (unsigned)l)
 549                 return NULL;
 550         if (rr.rdlength > 1023)
 551                 return NULL;
 552
 553         switch (rr.type) {
 554                 case DNS_QRY_PTR:
 555                         o = 0;
 556                         q = 0;
 557                         while (q == 0 && i < l && o + 256 < 1023) {
 558                                 if (h.payload[i] > 63) { /* pointer */
 559                                         memcpy(&p,&h.payload[i],2);
 560                                         i = ntohs(p) - DNS_POINTER_VALUE - 12;
 561                                 } else { /* label */
 562                                         if (h.payload[i] == 0)
 563                                                 q = 1;
 564                                         else {
 565                                                 res[o] = '\0';
 566                                                 if (o != 0)
 567                                                         res[o++] = '.';
 568                                                 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
 569                                                 o += h.payload[i];
 570                                                 i += h.payload[i] + 1;
 571                                         }
 572                                 }
 573                         }
 574                         res[o] = '\0';
 575                         break;
 576                 case DNS_QRY_A:
 577                         if (c->want_list) {
 578                                 dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
 579                                 while ((char *)alist - (char *)res < 700) {
 580                                         if (rr.type != DNS_QRY_A)
 581                                                 break;
 582                                         if (rr._class != 1)
 583                                                 break;
 584                                         if (rr.rdlength != 4) {
 585                                                 delete c;
 586                                                 return NULL;
 587                                         }
 588                                         memcpy(&alist->ip,&h.payload[i],4);
 589                                         if ((unsigned)++curanswer >= h.ancount)
 590                                                 break;
 591                                         i += rr.rdlength;
 592                                         {
 593                                                 /* skip next name */
 594                                                 q = 0;
 595                                                 while (q == 0 && i < l) {
 596                                                         if (h.payload[i] > 63) { /* pointer */
 597                                                                 i += 2; /* skip pointer */
 598                                                                 q = 1;
 599                                                         } else { /* label */
 600                                                                 if (h.payload[i] == 0) {
 601                                                                         i++;
 602                                                                         q = 1;
 603                                                                 } else
 604                                                                         i += h.payload[i] + 1; /* skip length and label */
 605                                                         }
 606                                                 }
 607                                         }
 608                                         if (l - i < 10) {
 609                                                 delete c;
 610                                                 return NULL;
 611                                         }
 612                                         dns_fill_rr(&rr,&h.payload[i]);
 613                                         i += 10;
 614                                         alist->next = (dns_ip4list *) dns_align(((char *) alist) + sizeof(dns_ip4list));
 615                                         alist = alist->next;
 616                                         alist->next = NULL;
 617                                 }
 618                                 alist->next = NULL;
 619                                 break;
 620                         }
 621                         goto defaultcase;
 622                         break;
 623                 default:
 624                 defaultcase:
 625                         memcpy(res,&h.payload[i],rr.rdlength);
 626                         res[rr.rdlength] = '\0';
 627                         break;
 628         }
 629         delete c;
 630         return res;
 631 }
 632
 633 DNS::DNS()
 634 {
 635         dns_init();
 636 }
 637
 638 DNS::DNS(std::string dnsserver)
 639 {
 640         dns_init_2(dnsserver.c_str());
 641 }
 642
 643 void DNS::SetNS(std::string dnsserver)
 644 {
 645         dns_init_2(dnsserver.c_str());
 646 }
 647
 648 DNS::~DNS()
 649 {
 650 }
 651
 652 bool DNS::ReverseLookup(std::string ip)
 653 {
 654         statsDns++;
 655         binip = dns_aton4(ip.c_str());
 656         if (binip == NULL) {
 657                 return false;
 658         }
 659
 660         this->fd = dns_getname4(binip);
 661         if (this->fd == -1)
 662         {
 663                 return false;
 664         }
 665         return true;
 666 }
 667
 668 bool DNS::ForwardLookup(std::string host)
 669 {
 670         statsDns++;
 671         this->fd = dns_getip4(host.c_str());
 672         if (this->fd == -1)
 673         {
 674                 return false;
 675         }
 676         return true;
 677 }
 678
 679 bool DNS::HasResult()
 680 {
 681         pollfd polls;
 682         polls.fd = this->fd;
 683         polls.events = POLLIN;
 684         int ret = poll(&polls,1,1);
 685         return (ret > 0);
 686 }
 687
 688 int DNS::GetFD()
 689 {
 690         return this->fd;
 691 }
 692
 693 std::string DNS::GetResult()
 694 {
 695         result = dns_getresult(this->fd);
 696         if (result) {
 697                 statsDnsGood++;
 698                 dns_close(this->fd);
 699                 return result;
 700         } else {
 701                 statsDnsBad++;
 702                 if (this->fd != -1)
 703                 {
 704                         dns_close(this->fd);
 705                 }
 706                 return "";
 707         }
 708 }
 709
 710 std::string DNS::GetResultIP()
 711 {
 712         char r[1024];
 713         result = dns_getresult(this->fd);
 714         if (this->fd != -1)
 715         {
 716                 dns_close(this->fd);
 717         }
 718         if (result)
 719         {
 720                 sprintf(r,"%ld.%ld.%ld.%ld",result[0],result[1],result[2],result[3]);
 721                 return r;
 722         }
 723         else
 724         {
 725                 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
 726                 return "";
 727         }
 728 }