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 #include "socketengine.h"
  41
  42 extern SocketEngine* SE;
  43
  44 extern int statsAccept,statsRefused,statsUnknown,statsCollisions,statsDns,statsDnsGood,statsDnsBad,statsConnects,statsSent,statsRecv;
  45
  46 #define max(a,b) (a > b ? a : b)
  47 #define DNS_MAX              8                    /* max number of nameservers used */
  48 #define DNS_CONFIG_FBCK     "/etc/resolv.conf"    /* fallback config file */
  49 #define DNS_PORT            53                    /* DNS well known port */
  50 #define DNS_QRY_A            1                    /* name to IP address */
  51 #define DNS_QRY_AAAA        28                    /* name to IP6 address */
  52 #define DNS_QRY_PTR         12                    /* IP address to name */
  53 #define DNS_QRY_MX          15                    /* name to MX */
  54 #define DNS_QRY_TXT         16                    /* name to TXT */
  55 #define DNS_QRY_CNAME       5
  56
  57 #define DNS_ALIGN (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long))
  58 #define DNS_TRIES 3
  59 #define RESULTSIZE 1024
  60 #define min(a,b) (a < b ? a : b)
  61
  62 static struct in_addr servers4[DNS_MAX]; /* up to DNS_MAX nameservers; populated by dns_init() */
  63 static int i4; /* actual count of nameservers; set by dns_init() */
  64
  65 static int initdone = 0; /* to ensure dns_init() only runs once (on the first call) */
  66 static int wantclose = 0;
  67 static int lastcreate = -1;
  68
  69 struct s_connection { /* open DNS query */
  70         struct s_connection *next; /* next in list */
  71         unsigned char id[2];
  72         unsigned int _class;
  73         unsigned int type;
  74         int want_list;
  75         int fd; /* file descriptor returned from sockets */
  76 };
  77
  78 struct s_rr_middle {
  79         unsigned int type;
  80         unsigned int _class;
  81         unsigned long ttl;
  82         unsigned int rdlength;
  83 };
  84
  85 #define DNS_POINTER_VALUE 0xc000
  86
  87 static s_connection *connection_head = NULL; /* linked list of open DNS queries; populated by dns_add_query(), decimated by dns_getresult_s() */
  88
  89 struct s_header { /* DNS query header */
  90         unsigned char id[2];
  91         unsigned int flags1;
  92 #define FLAGS1_MASK_QR 0x80
  93 #define FLAGS1_MASK_OPCODE 0x78 /* bitshift right 3 */
  94 #define FLAGS1_MASK_AA 0x04
  95 #define FLAGS1_MASK_TC 0x02
  96 #define FLAGS1_MASK_RD 0x01
  97         unsigned int flags2;
  98 #define FLAGS2_MASK_RA 0x80
  99 #define FLAGS2_MASK_Z  0x70
 100 #define FLAGS2_MASK_RCODE 0x0f
 101         unsigned int qdcount;
 102         unsigned int ancount;
 103         unsigned int nscount;
 104         unsigned int arcount;
 105         unsigned char payload[512]; /* DNS question, populated by dns_build_query_payload() */
 106 };
 107
 108 extern time_t TIME;
 109
 110 void *dns_align(void *inp) {
 111         char *p = (char*)inp;
 112         int offby = ((char *)p - (char *)0) % DNS_ALIGN;
 113         if (offby != 0)
 114                 return p + (DNS_ALIGN - offby);
 115         else
 116                 return p;
 117 }
 118
 119 /*
 120  * These little hacks are here to avoid alignment and type sizing issues completely by doing manual copies
 121  */
 122 void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
 123         rr->type = input[0] * 256 + input[1];
 124         rr->_class = input[2] * 256 + input[3];
 125         rr->ttl = input[4] * 16777216 + input[5] * 65536 + input[6] * 256 + input[7];
 126         rr->rdlength = input[8] * 256 + input[9];
 127 }
 128
 129 void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
 130         header->id[0] = input[0];
 131         header->id[1] = input[1];
 132         header->flags1 = input[2];
 133         header->flags2 = input[3];
 134         header->qdcount = input[4] * 256 + input[5];
 135         header->ancount = input[6] * 256 + input[7];
 136         header->nscount = input[8] * 256 + input[9];
 137         header->arcount = input[10] * 256 + input[11];
 138         memcpy(header->payload,&input[12],l);
 139 }
 140
 141 void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
 142         output[0] = header->id[0];
 143         output[1] = header->id[1];
 144         output[2] = header->flags1;
 145         output[3] = header->flags2;
 146         output[4] = header->qdcount / 256;
 147         output[5] = header->qdcount % 256;
 148         output[6] = header->ancount / 256;
 149         output[7] = header->ancount % 256;
 150         output[8] = header->nscount / 256;
 151         output[9] = header->nscount % 256;
 152         output[10] = header->arcount / 256;
 153         output[11] = header->arcount % 256;
 154         memcpy(&output[12],header->payload,l);
 155 }
 156
 157 void dns_close(int fd) { /* close query */
 158         log(DEBUG,"DNS: dns_close on fd %d",fd);
 159         if (fd == lastcreate) {
 160                 wantclose = 1;
 161                 return;
 162         }
 163         shutdown(fd,2);
 164         close(fd);
 165         return;
 166 }
 167
 168 void DNS::dns_init() { /* on first call only: populates servers4 struct with up to DNS_MAX nameserver IP addresses from /etc/resolv.conf */
 169         FILE *f;
 170         int i;
 171         in_addr addr4;
 172         char buf[1024];
 173         if (initdone == 1)
 174                 return;
 175         i4 = 0;
 176
 177         initdone = 1;
 178         srand((unsigned int) TIME);
 179         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 180         f = fopen(DNS_CONFIG_FBCK,"r");
 181         if (f == NULL)
 182                 return;
 183         while (fgets(buf,1024,f) != NULL) {
 184                 if (strncmp(buf,"nameserver",10) == 0) {
 185                         i = 10;
 186                         while (buf[i] == ' ' || buf[i] == '\t')
 187                                 i++;
 188                         if (i4 < DNS_MAX) {
 189                                 if (dns_aton4_s(&buf[i],&addr4) != NULL)
 190                                         memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 191                         }
 192                 }
 193         }
 194         fclose(f);
 195 }
 196
 197 void DNS::dns_init_2(const char* dnsserver)
 198 {
 199         in_addr addr4;
 200         i4 = 0;
 201         srand((unsigned int) TIME);
 202         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 203         if (dns_aton4_s(dnsserver,&addr4) != NULL)
 204             memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 205 }
 206
 207
 208 static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
 209 {
 210         int i;
 211         sockaddr_in addr4;
 212         unsigned char payload[sizeof(s_header)];
 213
 214         dns_empty_header(payload,h,l);
 215
 216
 217         i = 0;
 218
 219         /* otherwise send via standard ipv4 boringness */
 220         memset(&addr4,0,sizeof(addr4));
 221         memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
 222         addr4.sin_family = AF_INET;
 223         addr4.sin_port = htons(DNS_PORT);
 224         if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
 225         {
 226                 return -1;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
 233         s_connection * s;
 234
 235         s = new s_connection;
 236
 237         /* set header flags */
 238         h->id[0] = s->id[0] = rand() % 255; /* verified by dns_getresult_s() */
 239         h->id[1] = s->id[1] = rand() % 255;
 240         h->flags1 = 0 | FLAGS1_MASK_RD;
 241         h->flags2 = 0;
 242         h->qdcount = 1;
 243         h->ancount = 0;
 244         h->nscount = 0;
 245         h->arcount = 0;
 246
 247         /* turn off want_list by default */
 248         s->want_list = 0;
 249
 250         /* try to create ipv6 or ipv4 socket */
 251                 s->fd = socket(PF_INET, SOCK_DGRAM, 0);
 252                 if (s->fd != -1) {
 253                         if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
 254                                 shutdown(s->fd,2);
 255                                 close(s->fd);
 256                                 s->fd = -1;
 257                         }
 258                 }
 259                 if (s->fd != -1) {
 260                         sockaddr_in addr;
 261                         memset(&addr,0,sizeof(addr));
 262                         addr.sin_family = AF_INET;
 263                         addr.sin_port = 0;
 264                         addr.sin_addr.s_addr = INADDR_ANY;
 265                         if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
 266                                 shutdown(s->fd,2);
 267                                 close(s->fd);
 268                                 s->fd = -1;
 269                         }
 270                 }
 271                 if (s->fd == -1) {
 272                         delete s;
 273                         return NULL;
 274                 }
 275         /* create new connection object, add to linked list */
 276         s->next = connection_head;
 277         connection_head = s;
 278
 279         if (wantclose == 1) {
 280                 shutdown(lastcreate,2);
 281                 close(lastcreate);
 282                 wantclose = 0;
 283         }
 284         lastcreate = s->fd;
 285         return s;
 286 }
 287
 288 static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
 289         short payloadpos;
 290         const char * tempchr, * tempchr2;
 291         unsigned short l;
 292
 293         payloadpos = 0;
 294         tempchr2 = name;
 295
 296         /* split name up into labels, create query */
 297         while ((tempchr = strchr(tempchr2,'.')) != NULL) {
 298                 l = tempchr - tempchr2;
 299                 if (payloadpos + l + 1 > 507)
 300                         return -1;
 301                 payload[payloadpos++] = l;
 302                 memcpy(&payload[payloadpos],tempchr2,l);
 303                 payloadpos += l;
 304                 tempchr2 = &tempchr[1];
 305         }
 306         l = strlen(tempchr2);
 307         if (l) {
 308                 if (payloadpos + l + 2 > 507)
 309                         return -1;
 310                 payload[payloadpos++] = l;
 311                 memcpy(&payload[payloadpos],tempchr2,l);
 312                 payloadpos += l;
 313                 payload[payloadpos++] = '\0';
 314         }
 315         if (payloadpos > 508)
 316                 return -1;
 317         l = htons(rr);
 318         memcpy(&payload[payloadpos],&l,2);
 319         l = htons(_class);
 320         memcpy(&payload[payloadpos + 2],&l,2);
 321         return payloadpos + 4;
 322 }
 323
 324 in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
 325         static in_addr ip;
 326         return dns_aton4_s(ipstring,&ip);
 327 }
 328
 329 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
 330         in_addr* ip;
 331         ip = new in_addr;
 332         if(dns_aton4_s(ipstring,ip) == NULL) {
 333                 delete ip;
 334                 return NULL;
 335         }
 336         return ip;
 337 }
 338
 339 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
 340         inet_aton(ipstring,ip);
 341         return ip;
 342 }
 343
 344 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 345         s_header h;
 346         s_connection *s;
 347         int l;
 348
 349         dns_init();
 350
 351
 352         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 353         if (l == -1)
 354                 return -1;
 355         s = dns_add_query(&h);
 356         if (s == NULL)
 357                 return -1;
 358         s->_class = 1;
 359         s->type = DNS_QRY_A;
 360         if (dns_send_requests(&h,s,l) == -1)
 361                 return -1;
 362
 363         return s->fd;
 364 }
 365
 366 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 367         s_header h;
 368         s_connection *s;
 369         int l;
 370
 371         dns_init();
 372
 373
 374         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 375         if (l == -1)
 376                 return -1;
 377         s = dns_add_query(&h);
 378         if (s == NULL)
 379                 return -1;
 380         s->_class = 1;
 381         s->type = DNS_QRY_A;
 382         s->want_list = 1;
 383         if (dns_send_requests(&h,s,l) == -1)
 384                 return -1;
 385
 386         return s->fd;
 387 }
 388
 389 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
 390         char query[512];
 391         s_header h;
 392         s_connection * s;
 393         unsigned char *c;
 394         int l;
 395
 396         c = (unsigned char *)&ip->s_addr;
 397
 398         sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
 399
 400         l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
 401         if (l == -1)
 402                 return -1;
 403         s = dns_add_query(&h);
 404         if (s == NULL)
 405                 return -1;
 406         s->_class = 1;
 407         s->type = DNS_QRY_PTR;
 408         if (dns_send_requests(&h,s,l) == -1)
 409                 return -1;
 410
 411         return s->fd;
 412 }
 413
 414 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
 415         static char r[256];
 416         return dns_ntoa4_s(ip,r);
 417 }
 418
 419 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
 420         unsigned char *m;
 421         m = (unsigned char *)&ip->s_addr;
 422         sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
 423         return r;
 424 }
 425
 426 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
 427         log(DEBUG,"DNS: dns_getresult with cfd=%d",cfd);
 428         return dns_getresult_s(cfd,this->localbuf);
 429 }
 430
 431 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
 432         s_header h;
 433         s_connection *c, *prev;
 434         int l,i,q,curanswer,o;
 435         s_rr_middle rr;
 436         unsigned char buffer[sizeof(s_header)];
 437         unsigned short p;
 438
 439         if (res)
 440         {
 441                 res[0] = 0;
 442         }
 443
 444         prev = NULL;
 445         c = connection_head;
 446         while (c != NULL) { /* find query in list of open queries */
 447                 if (c->fd == cfd)
 448                         break;
 449                 prev = c;
 450                 c = c->next;
 451         }
 452         if (c == NULL) {
 453                 log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d",cfd);
 454                 return NULL; /* query not found */
 455         }
 456         /* query found-- pull from list: */
 457         if (prev != NULL)
 458                 prev->next = c->next;
 459         else
 460                 connection_head = c->next;
 461
 462         l = recv(c->fd,buffer,sizeof(s_header),0);
 463         dns_close(c->fd);
 464         if (l < 12) {
 465                 delete c;
 466                 return NULL;
 467         }
 468         dns_fill_header(&h,buffer,l - 12);
 469         if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
 470                 log(DEBUG,"DNS: id mismatch on query");
 471                 delete c;
 472                 return NULL; /* ID mismatch */
 473         }
 474         if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
 475                 log(DEBUG,"DNS: didnt get a query result");
 476                 delete c;
 477                 return NULL;
 478         }
 479         if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
 480                 log(DEBUG,"DNS: got an OPCODE and didnt want one");
 481                 delete c;
 482                 return NULL;
 483         }
 484         if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
 485                 log(DEBUG,"DNS lookup failed due to SERVFAIL");
 486                 delete c;
 487                 return NULL;
 488         }
 489         if (h.ancount < 1)  { /* no sense going on if we don't have any answers */
 490                 log(DEBUG,"DNS: no answers!");
 491                 delete c;
 492                 return NULL;
 493         }
 494         /* skip queries */
 495         i = 0;
 496         q = 0;
 497         l -= 12;
 498         while ((unsigned)q < h.qdcount && i < l) {
 499                 if (h.payload[i] > 63) { /* pointer */
 500                         i += 6; /* skip pointer, _class and type */
 501                         q++;
 502                 } else { /* label */
 503                         if (h.payload[i] == 0) {
 504                                 q++;
 505                                 i += 5; /* skip nil, _class and type */
 506                         } else
 507                                 i += h.payload[i] + 1; /* skip length and label */
 508                 }
 509         }
 510         /* &h.payload[i] should now be the start of the first response */
 511         curanswer = 0;
 512         while ((unsigned)curanswer < h.ancount) {
 513                 q = 0;
 514                 while (q == 0 && i < l) {
 515                         if (h.payload[i] > 63) { /* pointer */
 516                                 i += 2; /* skip pointer */
 517                                 q = 1;
 518                         } else { /* label */
 519                                 if (h.payload[i] == 0) {
 520                                         i++;
 521                                         q = 1;
 522                                 } else
 523                                         i += h.payload[i] + 1; /* skip length and label */
 524                         }
 525                 }
 526                 if (l - i < 10) {
 527                         delete c;
 528                         return NULL;
 529                 }
 530                 dns_fill_rr(&rr,&h.payload[i]);
 531                 i += 10;
 532                 if (rr.type != c->type) {
 533                         curanswer++;
 534                         i += rr.rdlength;
 535                         continue;
 536                 }
 537                 if (rr._class != c->_class) {
 538                         curanswer++;
 539                         i += rr.rdlength;
 540                         continue;
 541                 }
 542                 break;
 543         }
 544         if ((unsigned)curanswer == h.ancount)
 545                 return NULL;
 546         if ((unsigned)i + rr.rdlength > (unsigned)l)
 547                 return NULL;
 548         if (rr.rdlength > 1023)
 549                 return NULL;
 550
 551         switch (rr.type) {
 552                 case DNS_QRY_PTR:
 553                         log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
 554                         o = 0;
 555                         q = 0;
 556                         while (q == 0 && i < l && o + 256 < 1023) {
 557                                 if (h.payload[i] > 63) { /* pointer */
 558                                         memcpy(&p,&h.payload[i],2);
 559                                         i = ntohs(p) - DNS_POINTER_VALUE - 12;
 560                                 } else { /* label */
 561                                         if (h.payload[i] == 0)
 562                                                 q = 1;
 563                                         else {
 564                                                 res[o] = '\0';
 565                                                 if (o != 0)
 566                                                         res[o++] = '.';
 567                                                 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
 568                                                 o += h.payload[i];
 569                                                 i += h.payload[i] + 1;
 570                                         }
 571                                 }
 572                         }
 573                         res[o] = '\0';
 574                         break;
 575                 case DNS_QRY_A:
 576                         log(DEBUG,"DNS: got a result of type 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                         log(DEBUG,"DNS: doing something with result 'default'");
 626                         memcpy(res,&h.payload[i],rr.rdlength);
 627                         res[rr.rdlength] = '\0';
 628                         break;
 629         }
 630         delete c;
 631         return res;
 632 }
 633
 634 DNS::DNS()
 635 {
 636         dns_init();
 637         log(DEBUG,"Create blank DNS");
 638 }
 639
 640 DNS::DNS(std::string dnsserver)
 641 {
 642         dns_init_2(dnsserver.c_str());
 643         log(DEBUG,"Create DNS");
 644 }
 645
 646 void DNS::SetNS(std::string dnsserver)
 647 {
 648         dns_init_2(dnsserver.c_str());
 649         log(DEBUG,"Set NS");
 650 }
 651
 652 DNS::~DNS()
 653 {
 654 }
 655
 656 bool DNS::ReverseLookup(std::string ip)
 657 {
 658         statsDns++;
 659         binip = dns_aton4(ip.c_str());
 660         if (binip == NULL) {
 661                 return false;
 662         }
 663
 664         this->myfd = dns_getname4(binip);
 665         if (this->myfd == -1)
 666         {
 667                 return false;
 668         }
 669         log(DEBUG,"DNS: ReverseLookup, fd=%d",this->myfd);
 670 #ifndef THREADED_DNS
 671         SE->AddFd(this->myfd,true,X_ESTAB_DNS);
 672 #endif
 673         return true;
 674 }
 675
 676 bool DNS::ForwardLookup(std::string host)
 677 {
 678         statsDns++;
 679         this->myfd = dns_getip4(host.c_str());
 680         if (this->myfd == -1)
 681         {
 682                 return false;
 683         }
 684         log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
 685 #ifndef THREADED_DNS
 686         SE->AddFd(this->myfd,true,X_ESTAB_DNS);
 687 #endif
 688         return true;
 689 }
 690
 691 bool DNS::HasResult(int fd)
 692 {
 693         return (fd == this->myfd);
 694 }
 695
 696 /* Only the multithreaded dns uses this poll() based
 697  * check now. As its in another thread we dont have
 698  * to worry about its performance that much.
 699  */
 700 bool DNS::HasResult()
 701 {
 702         log(DEBUG,"DNS: HasResult, fd=%d",this->myfd);
 703         pollfd polls;
 704         polls.fd = this->myfd;
 705         polls.events = POLLIN;
 706         int ret = poll(&polls,1,1);
 707         log(DEBUG,"DNS: Hasresult returning %d",ret);
 708         return (ret > 0);
 709 }
 710
 711 int DNS::GetFD()
 712 {
 713         return this->myfd;
 714 }
 715
 716 std::string DNS::GetResult()
 717 {
 718         log(DEBUG,"DNS: GetResult()");
 719         result = dns_getresult(this->myfd);
 720 #ifndef THREADED_DNS
 721         SE->DelFd(this->myfd);
 722 #endif
 723         if (result) {
 724                 statsDnsGood++;
 725                 dns_close(this->myfd);
 726                 return result;
 727         } else {
 728                 statsDnsBad++;
 729                 if (this->myfd != -1)
 730                 {
 731                         dns_close(this->myfd);
 732                 }
 733                 return "";
 734         }
 735 }
 736
 737 std::string DNS::GetResultIP()
 738 {
 739         char r[1024];
 740         log(DEBUG,"DNS: GetResultIP()");
 741         result = dns_getresult(this->myfd);
 742         if (this->myfd != -1)
 743         {
 744 #ifndef THREADED_DNS
 745                 SE->DelFd(this->myfd);
 746 #endif
 747                 dns_close(this->myfd);
 748         }
 749         if (result)
 750         {
 751                 statsDnsGood++;
 752                 unsigned char a = (unsigned)result[0];
 753                 unsigned char b = (unsigned)result[1];
 754                 unsigned char c = (unsigned)result[2];
 755                 unsigned char d = (unsigned)result[3];
 756                 snprintf(r,1024,"%u.%u.%u.%u",a,b,c,d);
 757                 return r;
 758         }
 759         else
 760         {
 761                 statsDnsBad++;
 762                 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
 763                 return "";
 764         }
 765 }
 766