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)
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);
723 if (ServerInstance && ServerInstance->SE)
724 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
729 bool DNS::ForwardLookup(const std::string &host)
731 if (ServerInstance && ServerInstance->stats)
732 ServerInstance->stats->statsDns++;
733 this->myfd = dns_getip4(host.c_str());
734 if (this->myfd == -1)
738 log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
740 if (ServerInstance && ServerInstance->SE)
741 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
746 bool DNS::ForwardLookupWithFD(const std::string &host, int &fd)
748 if (ServerInstance && ServerInstance->stats)
749 ServerInstance->stats->statsDns++;
750 this->myfd = dns_getip4(host.c_str());
752 if (this->myfd == -1)
756 log(DEBUG,"DNS: ForwardLookupWithFD, fd=%d",this->myfd);
757 if (ServerInstance && ServerInstance->SE)
758 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_MODULE);
762 bool DNS::HasResult(int fd)
764 return (fd == this->myfd);
767 /* Only the multithreaded dns uses this poll() based
768 * check now. As its in another thread we dont have
769 * to worry about its performance that much.
771 bool DNS::HasResult()
773 log(DEBUG,"DNS: HasResult, fd=%d",this->myfd);
775 polls.fd = this->myfd;
776 polls.events = POLLIN;
777 int ret = poll(&polls,1,1);
778 log(DEBUG,"DNS: Hasresult returning %d",ret);
787 std::string DNS::GetResult()
789 log(DEBUG,"DNS: GetResult()");
790 result = dns_getresult(this->myfd);
793 if (ServerInstance && ServerInstance->stats)
794 ServerInstance->stats->statsDnsGood++;
795 dns_close(this->myfd);
800 if (ServerInstance && ServerInstance->stats)
801 ServerInstance->stats->statsDnsBad++;
802 if (this->myfd != -1)
804 dns_close(this->myfd);
810 std::string DNS::GetResultIP()
813 log(DEBUG,"DNS: GetResultIP()");
814 result = dns_getresult(this->myfd);
815 if (this->myfd != -1)
817 dns_close(this->myfd);
821 if (ServerInstance && ServerInstance->stats)
822 ServerInstance->stats->statsDnsGood++;
823 unsigned char a = (unsigned)result[0];
824 unsigned char b = (unsigned)result[1];
825 unsigned char c = (unsigned)result[2];
826 unsigned char d = (unsigned)result[3];
827 snprintf(r,1024,"%u.%u.%u.%u",a,b,c,d);
832 if (ServerInstance && ServerInstance->stats)
833 ServerInstance->stats->statsDnsBad++;
834 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
842 void* dns_task(void* arg)
844 userrec* u = (userrec*)arg;
845 log(DEBUG,"DNS thread for user %s",u->nick);
850 if (dns1.ReverseLookup((char*)inet_ntoa(u->ip4)))
852 while (!dns1.HasResult())
856 host = dns1.GetResult();
859 if (dns2.ForwardLookup(host))
861 while (!dns2.HasResult())
865 ip = dns2.GetResultIP();
866 if (ip == std::string((char*)inet_ntoa(u->ip4)))
868 if (host.length() < 160)
870 strcpy(u->host,host.c_str());
871 strcpy(u->dhost,host.c_str());
882 Resolver::Resolver(const std::string &source, bool forward, const std::string &dnsserver = "") : input(source), fwd(forward), server(dnsserver)
884 if (this->server != "")
885 Query.SetNS(this->server);
887 Query.SetNS(Config->DNSServer);
890 this->fd = Query.ForwardLookup(input.c_str());
892 this->fd = Query.ReverseLookup(input.c_str());
894 this->OnError(RESOLVER_NSDOWN);
896 if (ServerInstance && ServerInstance->SE)
897 ServerInstance->SE->AddFd(this->fd,true,X_ESTAB_CLASSDNS);
899 this->OnError(RESOLVER_NOTREADY);
902 Resolver::~Resolver()
904 if (ServerInstance && ServerInstance->SE)
905 ServerInstance->SE->DelFd(this->fd);
908 int Resolver::GetFd()
913 bool Resolver::ProcessResult()
916 result = Query.GetResultIP();
918 result = Query.GetResult();
922 this->OnLookupComplete(result);
927 this->OnError(RESOLVER_NXDOMAIN);
932 void Resolver::OnLookupComplete(const std::string &result)
936 void Resolver::OnError(ResolverError e)
940 void dns_deal_with_classes(int fd)
942 if ((fd > -1) && (dns_classes[fd]))
944 dns_classes[fd]->ProcessResult();
945 delete dns_classes[fd];
946 dns_classes[fd] = NULL;
950 bool dns_add_class(Resolver* r)
952 if ((r) && (r->GetFd() > -1))
954 if (!dns_classes[r->GetFd()])
956 dns_classes[r->GetFd()] = r;
973 memset(dns_classes,0,sizeof(dns_classes));