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 "inspircd.h"
  40 #include "helperfuncs.h"
  41 #include "socketengine.h"
  42
  43 extern InspIRCd* ServerInstance;
  44 extern ServerConfig* Config;
  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 #ifndef THREADED_DNS
 159         ServerInstance->SE->DelFd(fd);
 160 #endif
 161         log(DEBUG,"DNS: dns_close on fd %d",fd);
 162         if (fd == lastcreate) {
 163                 wantclose = 1;
 164                 return;
 165         }
 166         shutdown(fd,2);
 167         close(fd);
 168         return;
 169 }
 170
 171 void DNS::dns_init() { /* on first call only: populates servers4 struct with up to DNS_MAX nameserver IP addresses from /etc/resolv.conf */
 172         FILE *f;
 173         int i;
 174         in_addr addr4;
 175         char buf[1024];
 176         if (initdone == 1)
 177                 return;
 178         i4 = 0;
 179
 180         initdone = 1;
 181         srand((unsigned int) TIME);
 182         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 183         f = fopen(DNS_CONFIG_FBCK,"r");
 184         if (f == NULL)
 185                 return;
 186         while (fgets(buf,1024,f) != NULL) {
 187                 if (strncmp(buf,"nameserver",10) == 0) {
 188                         i = 10;
 189                         while (buf[i] == ' ' || buf[i] == '\t')
 190                                 i++;
 191                         if (i4 < DNS_MAX) {
 192                                 if (dns_aton4_s(&buf[i],&addr4) != NULL)
 193                                         memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 194                         }
 195                 }
 196         }
 197         fclose(f);
 198 }
 199
 200 void DNS::dns_init_2(const char* dnsserver)
 201 {
 202         in_addr addr4;
 203         i4 = 0;
 204         srand((unsigned int) TIME);
 205         memset(servers4,'\0',sizeof(in_addr) * DNS_MAX);
 206         if (dns_aton4_s(dnsserver,&addr4) != NULL)
 207             memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
 208 }
 209
 210
 211 static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
 212 {
 213         int i;
 214         sockaddr_in addr4;
 215         unsigned char payload[sizeof(s_header)];
 216
 217         dns_empty_header(payload,h,l);
 218
 219
 220         i = 0;
 221
 222         /* otherwise send via standard ipv4 boringness */
 223         memset(&addr4,0,sizeof(addr4));
 224         memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
 225         addr4.sin_family = AF_INET;
 226         addr4.sin_port = htons(DNS_PORT);
 227         if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
 228         {
 229                 return -1;
 230         }
 231
 232         return 0;
 233 }
 234
 235 static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
 236         s_connection * s;
 237
 238         s = new s_connection;
 239
 240         /* set header flags */
 241         h->id[0] = s->id[0] = rand() % 255; /* verified by dns_getresult_s() */
 242         h->id[1] = s->id[1] = rand() % 255;
 243         h->flags1 = 0 | FLAGS1_MASK_RD;
 244         h->flags2 = 0;
 245         h->qdcount = 1;
 246         h->ancount = 0;
 247         h->nscount = 0;
 248         h->arcount = 0;
 249
 250         /* turn off want_list by default */
 251         s->want_list = 0;
 252
 253         /* try to create ipv6 or ipv4 socket */
 254                 s->fd = socket(PF_INET, SOCK_DGRAM, 0);
 255                 if (s->fd != -1) {
 256                         if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
 257                                 shutdown(s->fd,2);
 258                                 close(s->fd);
 259                                 s->fd = -1;
 260                         }
 261                 }
 262                 if (s->fd != -1) {
 263                         sockaddr_in addr;
 264                         memset(&addr,0,sizeof(addr));
 265                         addr.sin_family = AF_INET;
 266                         addr.sin_port = 0;
 267                         addr.sin_addr.s_addr = INADDR_ANY;
 268                         if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
 269                                 shutdown(s->fd,2);
 270                                 close(s->fd);
 271                                 s->fd = -1;
 272                         }
 273                 }
 274                 if (s->fd == -1) {
 275                         delete s;
 276                         return NULL;
 277                 }
 278         /* create new connection object, add to linked list */
 279         s->next = connection_head;
 280         connection_head = s;
 281
 282         if (wantclose == 1) {
 283                 shutdown(lastcreate,2);
 284                 close(lastcreate);
 285                 wantclose = 0;
 286         }
 287         lastcreate = s->fd;
 288         return s;
 289 }
 290
 291 static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
 292         short payloadpos;
 293         const char * tempchr, * tempchr2;
 294         unsigned short l;
 295
 296         payloadpos = 0;
 297         tempchr2 = name;
 298
 299         /* split name up into labels, create query */
 300         while ((tempchr = strchr(tempchr2,'.')) != NULL) {
 301                 l = tempchr - tempchr2;
 302                 if (payloadpos + l + 1 > 507)
 303                         return -1;
 304                 payload[payloadpos++] = l;
 305                 memcpy(&payload[payloadpos],tempchr2,l);
 306                 payloadpos += l;
 307                 tempchr2 = &tempchr[1];
 308         }
 309         l = strlen(tempchr2);
 310         if (l) {
 311                 if (payloadpos + l + 2 > 507)
 312                         return -1;
 313                 payload[payloadpos++] = l;
 314                 memcpy(&payload[payloadpos],tempchr2,l);
 315                 payloadpos += l;
 316                 payload[payloadpos++] = '\0';
 317         }
 318         if (payloadpos > 508)
 319                 return -1;
 320         l = htons(rr);
 321         memcpy(&payload[payloadpos],&l,2);
 322         l = htons(_class);
 323         memcpy(&payload[payloadpos + 2],&l,2);
 324         return payloadpos + 4;
 325 }
 326
 327 in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
 328         static in_addr ip;
 329         return dns_aton4_s(ipstring,&ip);
 330 }
 331
 332 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
 333         in_addr* ip;
 334         ip = new in_addr;
 335         if(dns_aton4_s(ipstring,ip) == NULL) {
 336                 delete ip;
 337                 return NULL;
 338         }
 339         return ip;
 340 }
 341
 342 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
 343         inet_aton(ipstring,ip);
 344         return ip;
 345 }
 346
 347 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 348         s_header h;
 349         s_connection *s;
 350         int l;
 351
 352         dns_init();
 353
 354
 355         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 356         if (l == -1)
 357                 return -1;
 358         s = dns_add_query(&h);
 359         if (s == NULL)
 360                 return -1;
 361         s->_class = 1;
 362         s->type = DNS_QRY_A;
 363         if (dns_send_requests(&h,s,l) == -1)
 364                 return -1;
 365
 366         return s->fd;
 367 }
 368
 369 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
 370         s_header h;
 371         s_connection *s;
 372         int l;
 373
 374         dns_init();
 375
 376
 377         l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
 378         if (l == -1)
 379                 return -1;
 380         s = dns_add_query(&h);
 381         if (s == NULL)
 382                 return -1;
 383         s->_class = 1;
 384         s->type = DNS_QRY_A;
 385         s->want_list = 1;
 386         if (dns_send_requests(&h,s,l) == -1)
 387                 return -1;
 388
 389         return s->fd;
 390 }
 391
 392 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
 393         char query[512];
 394         s_header h;
 395         s_connection * s;
 396         unsigned char *c;
 397         int l;
 398
 399         c = (unsigned char *)&ip->s_addr;
 400
 401         sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
 402
 403         l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
 404         if (l == -1)
 405                 return -1;
 406         s = dns_add_query(&h);
 407         if (s == NULL)
 408                 return -1;
 409         s->_class = 1;
 410         s->type = DNS_QRY_PTR;
 411         if (dns_send_requests(&h,s,l) == -1)
 412                 return -1;
 413
 414         return s->fd;
 415 }
 416
 417 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
 418         static char r[256];
 419         return dns_ntoa4_s(ip,r);
 420 }
 421
 422 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
 423         unsigned char *m;
 424         m = (unsigned char *)&ip->s_addr;
 425         sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
 426         return r;
 427 }
 428
 429 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
 430         log(DEBUG,"DNS: dns_getresult with cfd=%d",cfd);
 431         return dns_getresult_s(cfd,this->localbuf);
 432 }
 433
 434 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
 435         s_header h;
 436         s_connection *c, *prev;
 437         int l,i,q,curanswer,o;
 438         s_rr_middle rr;
 439         unsigned char buffer[sizeof(s_header)];
 440         unsigned short p;
 441
 442         if (res)
 443         {
 444                 res[0] = 0;
 445         }
 446
 447         prev = NULL;
 448         c = connection_head;
 449         while (c != NULL) { /* find query in list of open queries */
 450                 if (c->fd == cfd)
 451                         break;
 452                 prev = c;
 453                 c = c->next;
 454         }
 455         if (c == NULL) {
 456                 log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d",cfd);
 457                 return NULL; /* query not found */
 458         }
 459         /* query found-- pull from list: */
 460         if (prev != NULL)
 461                 prev->next = c->next;
 462         else
 463                 connection_head = c->next;
 464
 465         l = recv(c->fd,buffer,sizeof(s_header),0);
 466         dns_close(c->fd);
 467         if (l < 12) {
 468                 delete c;
 469                 return NULL;
 470         }
 471         dns_fill_header(&h,buffer,l - 12);
 472         if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
 473                 log(DEBUG,"DNS: id mismatch on query");
 474                 delete c;
 475                 return NULL; /* ID mismatch */
 476         }
 477         if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
 478                 log(DEBUG,"DNS: didnt get a query result");
 479                 delete c;
 480                 return NULL;
 481         }
 482         if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
 483                 log(DEBUG,"DNS: got an OPCODE and didnt want one");
 484                 delete c;
 485                 return NULL;
 486         }
 487         if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
 488                 log(DEBUG,"DNS lookup failed due to SERVFAIL");
 489                 delete c;
 490                 return NULL;
 491         }
 492         if (h.ancount < 1)  { /* no sense going on if we don't have any answers */
 493                 log(DEBUG,"DNS: no answers!");
 494                 delete c;
 495                 return NULL;
 496         }
 497         /* skip queries */
 498         i = 0;
 499         q = 0;
 500         l -= 12;
 501         while ((unsigned)q < h.qdcount && i < l) {
 502                 if (h.payload[i] > 63) { /* pointer */
 503                         i += 6; /* skip pointer, _class and type */
 504                         q++;
 505                 } else { /* label */
 506                         if (h.payload[i] == 0) {
 507                                 q++;
 508                                 i += 5; /* skip nil, _class and type */
 509                         } else
 510                                 i += h.payload[i] + 1; /* skip length and label */
 511                 }
 512         }
 513         /* &h.payload[i] should now be the start of the first response */
 514         curanswer = 0;
 515         while ((unsigned)curanswer < h.ancount) {
 516                 q = 0;
 517                 while (q == 0 && i < l) {
 518                         if (h.payload[i] > 63) { /* pointer */
 519                                 i += 2; /* skip pointer */
 520                                 q = 1;
 521                         } else { /* label */
 522                                 if (h.payload[i] == 0) {
 523                                         i++;
 524                                         q = 1;
 525                                 } else
 526                                         i += h.payload[i] + 1; /* skip length and label */
 527                         }
 528                 }
 529                 if (l - i < 10) {
 530                         delete c;
 531                         return NULL;
 532                 }
 533                 dns_fill_rr(&rr,&h.payload[i]);
 534                 i += 10;
 535                 if (rr.type != c->type) {
 536                         curanswer++;
 537                         i += rr.rdlength;
 538                         continue;
 539                 }
 540                 if (rr._class != c->_class) {
 541                         curanswer++;
 542                         i += rr.rdlength;
 543                         continue;
 544                 }
 545                 break;
 546         }
 547         if ((unsigned)curanswer == h.ancount)
 548                 return NULL;
 549         if ((unsigned)i + rr.rdlength > (unsigned)l)
 550                 return NULL;
 551         if (rr.rdlength > 1023)
 552                 return NULL;
 553
 554         switch (rr.type) {
 555                 case DNS_QRY_PTR:
 556                         log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
 557                         o = 0;
 558                         q = 0;
 559                         while (q == 0 && i < l && o + 256 < 1023) {
 560                                 if (h.payload[i] > 63) { /* pointer */
 561                                         memcpy(&p,&h.payload[i],2);
 562                                         i = ntohs(p) - DNS_POINTER_VALUE - 12;
 563                                 } else { /* label */
 564                                         if (h.payload[i] == 0)
 565                                                 q = 1;
 566                                         else {
 567                                                 res[o] = '\0';
 568                                                 if (o != 0)
 569                                                         res[o++] = '.';
 570                                                 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
 571                                                 o += h.payload[i];
 572                                                 i += h.payload[i] + 1;
 573                                         }
 574                                 }
 575                         }
 576                         res[o] = '\0';
 577                         break;
 578                 case DNS_QRY_A:
 579                         log(DEBUG,"DNS: got a result of type DNS_QRY_A");
 580                         if (c->want_list) {
 581                                 dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
 582                                 while ((char *)alist - (char *)res < 700) {
 583                                         if (rr.type != DNS_QRY_A)
 584                                                 break;
 585                                         if (rr._class != 1)
 586                                                 break;
 587                                         if (rr.rdlength != 4) {
 588                                                 delete c;
 589                                                 return NULL;
 590                                         }
 591                                         memcpy(&alist->ip,&h.payload[i],4);
 592                                         if ((unsigned)++curanswer >= h.ancount)
 593                                                 break;
 594                                         i += rr.rdlength;
 595                                         {
 596                                                 /* skip next name */
 597                                                 q = 0;
 598                                                 while (q == 0 && i < l) {
 599                                                         if (h.payload[i] > 63) { /* pointer */
 600                                                                 i += 2; /* skip pointer */
 601                                                                 q = 1;
 602                                                         } else { /* label */
 603                                                                 if (h.payload[i] == 0) {
 604                                                                         i++;
 605                                                                         q = 1;
 606                                                                 } else
 607                                                                         i += h.payload[i] + 1; /* skip length and label */
 608                                                         }
 609                                                 }
 610                                         }
 611                                         if (l - i < 10) {
 612                                                 delete c;
 613                                                 return NULL;
 614                                         }
 615                                         dns_fill_rr(&rr,&h.payload[i]);
 616                                         i += 10;
 617                                         alist->next = (dns_ip4list *) dns_align(((char *) alist) + sizeof(dns_ip4list));
 618                                         alist = alist->next;
 619                                         alist->next = NULL;
 620                                 }
 621                                 alist->next = NULL;
 622                                 break;
 623                         }
 624                         goto defaultcase;
 625                         break;
 626                 default:
 627                 defaultcase:
 628                         log(DEBUG,"DNS: doing something with result 'default'");
 629                         memcpy(res,&h.payload[i],rr.rdlength);
 630                         res[rr.rdlength] = '\0';
 631                         break;
 632         }
 633         delete c;
 634         return res;
 635 }
 636
 637 DNS::DNS()
 638 {
 639         dns_init();
 640         log(DEBUG,"Create blank DNS");
 641 }
 642
 643 DNS::DNS(std::string dnsserver)
 644 {
 645         dns_init_2(dnsserver.c_str());
 646         log(DEBUG,"Create DNS");
 647 }
 648
 649 void DNS::SetNS(std::string dnsserver)
 650 {
 651         dns_init_2(dnsserver.c_str());
 652         log(DEBUG,"Set NS");
 653 }
 654
 655 DNS::~DNS()
 656 {
 657 }
 658
 659 bool DNS::ReverseLookup(std::string ip)
 660 {
 661         ServerInstance->stats->statsDns++;
 662         binip = dns_aton4(ip.c_str());
 663         if (binip == NULL) {
 664                 return false;
 665         }
 666
 667         this->myfd = dns_getname4(binip);
 668         if (this->myfd == -1)
 669         {
 670                 return false;
 671         }
 672         log(DEBUG,"DNS: ReverseLookup, fd=%d",this->myfd);
 673 #ifndef THREADED_DNS
 674         ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
 675 #endif
 676         return true;
 677 }
 678
 679 bool DNS::ForwardLookup(std::string host)
 680 {
 681         ServerInstance->stats->statsDns++;
 682         this->myfd = dns_getip4(host.c_str());
 683         if (this->myfd == -1)
 684         {
 685                 return false;
 686         }
 687         log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
 688 #ifndef THREADED_DNS
 689         ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
 690 #endif
 691         return true;
 692 }
 693
 694 bool DNS::HasResult(int fd)
 695 {
 696         return (fd == this->myfd);
 697 }
 698
 699 /* Only the multithreaded dns uses this poll() based
 700  * check now. As its in another thread we dont have
 701  * to worry about its performance that much.
 702  */
 703 bool DNS::HasResult()
 704 {
 705         log(DEBUG,"DNS: HasResult, fd=%d",this->myfd);
 706         pollfd polls;
 707         polls.fd = this->myfd;
 708         polls.events = POLLIN;
 709         int ret = poll(&polls,1,1);
 710         log(DEBUG,"DNS: Hasresult returning %d",ret);
 711         return (ret > 0);
 712 }
 713
 714 int DNS::GetFD()
 715 {
 716         return this->myfd;
 717 }
 718
 719 std::string DNS::GetResult()
 720 {
 721         log(DEBUG,"DNS: GetResult()");
 722         result = dns_getresult(this->myfd);
 723         if (result) {
 724                 ServerInstance->stats->statsDnsGood++;
 725                 dns_close(this->myfd);
 726                 return result;
 727         } else {
 728                 ServerInstance->stats->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                 dns_close(this->myfd);
 745         }
 746         if (result)
 747         {
 748                 ServerInstance->stats->statsDnsGood++;
 749                 unsigned char a = (unsigned)result[0];
 750                 unsigned char b = (unsigned)result[1];
 751                 unsigned char c = (unsigned)result[2];
 752                 unsigned char d = (unsigned)result[3];
 753                 snprintf(r,1024,"%u.%u.%u.%u",a,b,c,d);
 754                 return r;
 755         }
 756         else
 757         {
 758                 ServerInstance->stats->statsDnsBad++;
 759                 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
 760                 return "";
 761         }
 762 }
 763
 764
 765
 766 #ifdef THREADED_DNS
 767 void* dns_task(void* arg)
 768 {
 769         userrec* u = (userrec*)arg;
 770         log(DEBUG,"DNS thread for user %s",u->nick);
 771         DNS dns1;
 772         DNS dns2;
 773         std::string host;
 774         std::string ip;
 775         if (dns1.ReverseLookup(u->ip))
 776         {
 777                 while (!dns1.HasResult())
 778                 {
 779                         usleep(100);
 780                 }
 781                 host = dns1.GetResult();
 782                 if (host != "")
 783                 {
 784                         if (dns2.ForwardLookup(host))
 785                         {
 786                                 while (!dns2.HasResult())
 787                                 {
 788                                         usleep(100);
 789                                 }
 790                                 ip = dns2.GetResultIP();
 791                                 if (ip == std::string(u->ip))
 792                                 {
 793                                         if (host.length() < 160)
 794                                         {
 795                                                 strcpy(u->host,host.c_str());
 796                                                 strcpy(u->dhost,host.c_str());
 797                                         }
 798                                 }
 799                         }
 800                 }
 801         }
 802         u->dns_done = true;
 803         return NULL;
 804 }
 805 #endif