1 /* +------------------------------------+
2 * | Inspire Internet Relay Chat Daemon |
3 * +------------------------------------+
5 * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev.
7 * <brain@chatspike.net>
8 * <Craig@chatspike.net>
10 * Written by Craig Edwards, Craig McLure, and others.
11 * This program is free but copyrighted software; see
12 * the file COPYING for details.
14 * ---------------------------------------------------
18 dns.cpp - Nonblocking DNS functions.
19 Very loosely based on the firedns library,
20 Copyright (C) 2002 Ian Gulliver.
22 There have been so many modifications to this file
23 to make it fit into InspIRCd and make it object
24 orientated that you should not take this code as
25 being what firedns really looks like. It used to
26 look very different to this! :-P
34 #include <sys/types.h>
35 #include <sys/socket.h>
43 #include <sys/types.h>
44 #include <sys/socket.h>
45 #include <netinet/in.h>
46 #include <arpa/inet.h>
51 #include "helperfuncs.h"
52 #include "socketengine.h"
53 #include "configreader.h"
55 extern InspIRCd* ServerInstance;
56 extern ServerConfig* Config;
59 enum QueryType { DNS_QRY_A = 1, DNS_QRY_PTR = 12 };
60 enum QueryFlags1 { FLAGS1_MASK_RD = 0x01, FLAGS1_MASK_TC = 0x02, FLAGS1_MASK_AA = 0x04, FLAGS1_MASK_OPCODE = 0x78, FLAGS1_MASK_QR = 0x80 };
61 enum QueryFlags2 { FLAGS2_MASK_RCODE = 0x0F, FLAGS2_MASK_Z = 0x70, FLAGS2_MASK_RA = 0x80 };
65 typedef std::map<int,s_connection*> connlist;
66 typedef connlist::iterator connlist_iter;
69 Resolver* dns_classes[MAX_DESCRIPTORS];
71 struct in_addr servers4[8];
93 unsigned int rdlength;
102 unsigned int qdcount;
103 unsigned int ancount;
104 unsigned int nscount;
105 unsigned int arcount;
106 unsigned char payload[512];
110 void *dns_align(void *inp)
112 char *p = (char*)inp;
113 int offby = ((char *)p - (char *)0) % (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long));
115 return p + ((sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long)) - offby);
121 * Optimized by brain, these were using integer division and modulus.
122 * We can use logic shifts and logic AND to replace these even divisions
123 * and multiplications, it should be a bit faster (probably not noticably,
124 * but of course, more impressive). Also made these inline.
127 inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input)
129 rr->type = (QueryType)((input[0] << 8) + input[1]);
130 rr->_class = (input[2] << 8) + input[3];
131 rr->ttl = (input[4] << 24) + (input[5] << 16) + (input[6] << 8) + input[7];
132 rr->rdlength = (input[8] << 8) + input[9];
135 inline void dns_fill_header(s_header *header, const unsigned char *input, const int l)
137 header->id[0] = input[0];
138 header->id[1] = input[1];
139 header->flags1 = input[2];
140 header->flags2 = input[3];
141 header->qdcount = (input[4] << 8) + input[5];
142 header->ancount = (input[6] << 8) + input[7];
143 header->nscount = (input[8] << 8) + input[9];
144 header->arcount = (input[10] << 8) + input[11];
145 memcpy(header->payload,&input[12],l);
148 inline void dns_empty_header(unsigned char *output, const s_header *header, const int l)
150 output[0] = header->id[0];
151 output[1] = header->id[1];
152 output[2] = header->flags1;
153 output[3] = header->flags2;
154 output[4] = header->qdcount >> 8;
155 output[5] = header->qdcount & 0xFF;
156 output[6] = header->ancount >> 8;
157 output[7] = header->ancount & 0xFF;
158 output[8] = header->nscount >> 8;
159 output[9] = header->nscount & 0xFF;
160 output[10] = header->arcount >> 8;
161 output[11] = header->arcount & 0xFF;
162 memcpy(&output[12],header->payload,l);
165 void dns_close(int fd)
168 if (ServerInstance && ServerInstance->SE)
169 ServerInstance->SE->DelFd(fd);
171 log(DEBUG,"DNS: dns_close on fd %d",fd);
172 if (fd == lastcreate)
193 srand((unsigned int) TIME);
194 memset(servers4,'\0',sizeof(in_addr) * 8);
195 f = fopen("/etc/resolv.conf","r");
198 while (fgets(buf,1024,f) != NULL) {
199 if (strncmp(buf,"nameserver",10) == 0)
202 while (buf[i] == ' ' || buf[i] == '\t')
206 if (dns_aton4_s(&buf[i],&addr4) != NULL)
207 memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
214 void DNS::dns_init_2(const char* dnsserver)
218 srand((unsigned int) TIME);
219 memset(servers4,'\0',sizeof(in_addr) * 8);
220 if (dns_aton4_s(dnsserver,&addr4) != NULL)
221 memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
225 int dns_send_requests(const s_header *h, const s_connection *s, const int l)
229 unsigned char payload[sizeof(s_header)];
231 dns_empty_header(payload,h,l);
236 /* otherwise send via standard ipv4 boringness */
237 memset(&addr4,0,sizeof(addr4));
238 memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
239 addr4.sin_family = AF_INET;
240 addr4.sin_port = htons(53);
241 if (sendto(s->fd, payload, l + 12, 0, (sockaddr *) &addr4, sizeof(addr4)) == -1)
249 s_connection *dns_add_query(s_header *h)
252 s_connection * s = new s_connection;
253 int id = rand() % 65536;
255 /* set header flags */
256 h->id[0] = s->id[0] = id >> 8; /* verified by dns_getresult_s() */
257 h->id[1] = s->id[1] = id & 0xFF;
258 h->flags1 = 0 | FLAGS1_MASK_RD;
265 s->fd = socket(PF_INET, SOCK_DGRAM, 0);
268 if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0)
278 memset(&addr,0,sizeof(addr));
279 addr.sin_family = AF_INET;
281 addr.sin_addr.s_addr = INADDR_ANY;
282 if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0)
294 /* create new connection object, add to linked list */
295 if (connections.find(s->fd) == connections.end())
296 connections[s->fd] = s;
300 shutdown(lastcreate,2);
308 int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload)
311 const char * tempchr, * tempchr2;
317 /* split name up into labels, create query */
318 while ((tempchr = strchr(tempchr2,'.')) != NULL)
320 l = tempchr - tempchr2;
321 if (payloadpos + l + 1 > 507)
323 payload[payloadpos++] = l;
324 memcpy(&payload[payloadpos],tempchr2,l);
326 tempchr2 = &tempchr[1];
328 l = strlen(tempchr2);
331 if (payloadpos + l + 2 > 507)
333 payload[payloadpos++] = l;
334 memcpy(&payload[payloadpos],tempchr2,l);
336 payload[payloadpos++] = '\0';
338 if (payloadpos > 508)
341 memcpy(&payload[payloadpos],&l,2);
343 memcpy(&payload[payloadpos + 2],&l,2);
344 return payloadpos + 4;
347 in_addr* DNS::dns_aton4(const char * const ipstring)
350 return dns_aton4_s(ipstring,&ip);
353 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
356 if(dns_aton4_s(ipstring,ip) == NULL)
364 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
365 inet_aton(ipstring,ip);
369 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
377 l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
380 s = dns_add_query(&h);
385 if (dns_send_requests(&h,s,l) == -1)
391 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
398 l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
401 s = dns_add_query(&h);
407 if (dns_send_requests(&h,s,l) == -1)
413 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
420 c = (unsigned char *)&ip->s_addr;
422 sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
424 l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
427 s = dns_add_query(&h);
431 s->type = DNS_QRY_PTR;
432 if (dns_send_requests(&h,s,l) == -1)
438 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
440 return dns_ntoa4_s(ip,r);
443 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
445 m = (unsigned char *)&ip->s_addr;
446 sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
450 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
451 log(DEBUG,"DNS: dns_getresult with cfd=%d",cfd);
452 return dns_getresult_s(cfd,this->localbuf);
455 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
458 int l, i, q, curanswer, o;
460 unsigned char buffer[sizeof(s_header)];
466 /* FireDNS used a linked list for this. How ugly (and slow). */
467 connlist_iter n_iter = connections.find(cfd);
468 if (n_iter == connections.end())
470 log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d",cfd);
475 /* Remove the query from the list */
476 c = (s_connection*)n_iter->second;
477 /* We don't delete c here, because its done later when needed */
478 connections.erase(n_iter);
481 l = recv(c->fd,buffer,sizeof(s_header),0);
488 dns_fill_header(&h,buffer,l - 12);
489 if (c->id[0] != h.id[0] || c->id[1] != h.id[1])
491 log(DEBUG,"DNS: id mismatch on query");
493 return NULL; /* ID mismatch */
495 if ((h.flags1 & FLAGS1_MASK_QR) == 0)
497 log(DEBUG,"DNS: didnt get a query result");
501 if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0)
503 log(DEBUG,"DNS: got an OPCODE and didnt want one");
507 if ((h.flags2 & FLAGS2_MASK_RCODE) != 0)
509 log(DEBUG,"DNS lookup failed due to SERVFAIL");
515 log(DEBUG,"DNS: no answers!");
522 while ((unsigned)q < h.qdcount && i < l)
524 if (h.payload[i] > 63)
531 if (h.payload[i] == 0)
536 else i += h.payload[i] + 1;
540 while ((unsigned)curanswer < h.ancount)
543 while (q == 0 && i < l)
545 if (h.payload[i] > 63)
552 if (h.payload[i] == 0)
557 else i += h.payload[i] + 1; /* skip length and label */
565 dns_fill_rr(&rr,&h.payload[i]);
567 if (rr.type != c->type)
573 if (rr._class != c->_class)
581 if ((unsigned)curanswer == h.ancount)
583 if ((unsigned)i + rr.rdlength > (unsigned)l)
585 if (rr.rdlength > 1023)
591 log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
594 while (q == 0 && i < l && o + 256 < 1023)
596 if (h.payload[i] > 63)
598 memcpy(&p,&h.payload[i],2);
599 i = ntohs(p) - 0xC000 - 12;
603 if (h.payload[i] == 0)
612 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
614 i += h.payload[i] + 1;
621 log(DEBUG,"DNS: got a result of type DNS_QRY_A");
624 dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
625 while ((char *)alist - (char *)res < 700)
627 if (rr.type != DNS_QRY_A)
631 if (rr.rdlength != 4)
636 memcpy(&alist->ip,&h.payload[i],4);
637 if ((unsigned)++curanswer >= h.ancount)
641 while (q == 0 && i < l)
643 if (h.payload[i] > 63)
650 if (h.payload[i] == 0)
655 else i += h.payload[i] + 1;
663 dns_fill_rr(&rr,&h.payload[i]);
665 alist->next = (dns_ip4list *) dns_align(((char *) alist) + sizeof(dns_ip4list));
672 memcpy(res,&h.payload[i],rr.rdlength);
673 res[rr.rdlength] = '\0';
676 memcpy(res,&h.payload[i],rr.rdlength);
677 res[rr.rdlength] = '\0';
687 log(DEBUG,"Create blank DNS");
690 DNS::DNS(const std::string &dnsserver)
692 dns_init_2(dnsserver.c_str());
693 log(DEBUG,"Create DNS with server '%s'",dnsserver.c_str());
696 void DNS::SetNS(const std::string &dnsserver)
698 dns_init_2(dnsserver.c_str());
706 bool DNS::ReverseLookup(const std::string &ip, bool ins)
708 if (ServerInstance && ServerInstance->stats)
709 ServerInstance->stats->statsDns++;
710 binip = dns_aton4(ip.c_str());
716 this->myfd = dns_getname4(binip);
717 if (this->myfd == -1)
721 log(DEBUG,"DNS: ReverseLookup, fd=%d",this->myfd);
725 if (ServerInstance && ServerInstance->SE)
726 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
732 bool DNS::ForwardLookup(const std::string &host, bool ins)
734 if (ServerInstance && ServerInstance->stats)
735 ServerInstance->stats->statsDns++;
736 this->myfd = dns_getip4(host.c_str());
737 if (this->myfd == -1)
741 log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
745 if (ServerInstance && ServerInstance->SE)
746 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
752 bool DNS::ForwardLookupWithFD(const std::string &host, int &fd)
754 if (ServerInstance && ServerInstance->stats)
755 ServerInstance->stats->statsDns++;
756 this->myfd = dns_getip4(host.c_str());
758 if (this->myfd == -1)
762 log(DEBUG,"DNS: ForwardLookupWithFD, fd=%d",this->myfd);
763 if (ServerInstance && ServerInstance->SE)
764 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_MODULE);
768 bool DNS::HasResult(int fd)
770 return (fd == this->myfd);
773 /* Only the multithreaded dns uses this poll() based
774 * check now. As its in another thread we dont have
775 * to worry about its performance that much.
777 bool DNS::HasResult()
779 log(DEBUG,"DNS: HasResult, fd=%d",this->myfd);
781 polls.fd = this->myfd;
782 polls.events = POLLIN;
783 int ret = poll(&polls,1,1);
784 log(DEBUG,"DNS: Hasresult returning %d",ret);
793 std::string DNS::GetResult()
795 log(DEBUG,"DNS: GetResult()");
796 result = dns_getresult(this->myfd);
799 if (ServerInstance && ServerInstance->stats)
800 ServerInstance->stats->statsDnsGood++;
801 dns_close(this->myfd);
806 if (ServerInstance && ServerInstance->stats)
807 ServerInstance->stats->statsDnsBad++;
808 if (this->myfd != -1)
810 dns_close(this->myfd);
816 std::string DNS::GetResultIP()
819 log(DEBUG,"DNS: GetResultIP()");
820 result = dns_getresult(this->myfd);
821 if (this->myfd != -1)
823 dns_close(this->myfd);
827 if (ServerInstance && ServerInstance->stats)
828 ServerInstance->stats->statsDnsGood++;
829 unsigned char a = (unsigned)result[0];
830 unsigned char b = (unsigned)result[1];
831 unsigned char c = (unsigned)result[2];
832 unsigned char d = (unsigned)result[3];
833 snprintf(r,1024,"%u.%u.%u.%u",a,b,c,d);
838 if (ServerInstance && ServerInstance->stats)
839 ServerInstance->stats->statsDnsBad++;
840 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
848 void* dns_task(void* arg)
850 userrec* u = (userrec*)arg;
851 log(DEBUG,"DNS thread for user %s",u->nick);
856 if (dns1.ReverseLookup((char*)inet_ntoa(u->ip4)))
858 while (!dns1.HasResult())
862 host = dns1.GetResult();
865 if (dns2.ForwardLookup(host), false)
867 while (!dns2.HasResult())
871 ip = dns2.GetResultIP();
872 if (ip == std::string((char*)inet_ntoa(u->ip4)))
874 if (host.length() < 160)
876 strcpy(u->host,host.c_str());
877 strcpy(u->dhost,host.c_str());
888 Resolver::Resolver(const std::string &source, bool forward, const std::string &dnsserver = "") : input(source), fwd(forward), server(dnsserver)
890 if (this->server != "")
891 Query.SetNS(this->server);
893 Query.SetNS(Config->DNSServer);
897 Query.ForwardLookup(input.c_str(), false);
898 this->fd = Query.GetFD();
902 Query.ReverseLookup(input.c_str(), false);
903 this->Fd = Query.GetFD();
907 log(DEBUG,"Resolver::Resolver: RESOLVER_NSDOWN");
908 this->OnError(RESOLVER_NSDOWN);
912 if (ServerInstance && ServerInstance->SE)
914 log(DEBUG,"Resolver::Resolver: this->fd=%d",this->fd);
915 ServerInstance->SE->AddFd(this->fd,true,X_ESTAB_CLASSDNS);
919 log(DEBUG,"Resolver::Resolver: RESOLVER_NOTREADY");
920 this->OnError(RESOLVER_NOTREADY);
924 Resolver::~Resolver()
926 log(DEBUG,"Resolver::~Resolver");
927 if (ServerInstance && ServerInstance->SE)
928 ServerInstance->SE->DelFd(this->fd);
931 int Resolver::GetFd()
936 bool Resolver::ProcessResult()
938 log(DEBUG,"Resolver::ProcessResult");
940 result = Query.GetResultIP();
942 result = Query.GetResult();
946 log(DEBUG,"Resolver::OnLookupComplete(%s)",result.c_str());
947 this->OnLookupComplete(result);
952 log(DEBUG,"Resolver::OnError(RESOLVER_NXDOMAIN)");
953 this->OnError(RESOLVER_NXDOMAIN);
958 void Resolver::OnLookupComplete(const std::string &result)
962 void Resolver::OnError(ResolverError e)
966 void dns_deal_with_classes(int fd)
968 log(DEBUG,"dns_deal_with_classes(%d)",fd);
969 if ((fd > -1) && (dns_classes[fd]))
971 log(DEBUG,"Valid fd %d",fd);
972 dns_classes[fd]->ProcessResult();
973 delete dns_classes[fd];
974 dns_classes[fd] = NULL;
978 bool dns_add_class(Resolver* r)
980 log(DEBUG,"dns_add_class");
981 if ((r) && (r->GetFd() > -1))
983 if (!dns_classes[r->GetFd()])
985 log(DEBUG,"dns_add_class: added class");
986 dns_classes[r->GetFd()] = r;
991 log(DEBUG,"Space occupied!");
997 log(DEBUG,"Bad class");
1005 memset(dns_classes,0,sizeof(dns_classes));