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 "inspircd_config.h"
53 #include "socketengine.h"
54 #include "configreader.h"
57 pthread_mutex_t connmap_lock = PTHREAD_MUTEX_INITIALIZER;
60 extern InspIRCd* ServerInstance;
61 extern ServerConfig* Config;
63 extern userrec* fd_ref_table[MAX_DESCRIPTORS];
65 enum QueryType { DNS_QRY_A = 1, DNS_QRY_PTR = 12 };
66 enum QueryFlags1 { FLAGS1_MASK_RD = 0x01, FLAGS1_MASK_TC = 0x02, FLAGS1_MASK_AA = 0x04, FLAGS1_MASK_OPCODE = 0x78, FLAGS1_MASK_QR = 0x80 };
67 enum QueryFlags2 { FLAGS2_MASK_RCODE = 0x0F, FLAGS2_MASK_Z = 0x70, FLAGS2_MASK_RA = 0x80 };
71 typedef std::map<int,s_connection*> connlist;
72 typedef connlist::iterator connlist_iter;
75 Resolver* dns_classes[MAX_DESCRIPTORS];
77 struct in_addr servers4[8];
98 unsigned int rdlength;
107 unsigned int qdcount;
108 unsigned int ancount;
109 unsigned int nscount;
110 unsigned int arcount;
111 unsigned char payload[512];
115 void *dns_align(void *inp)
117 char *p = (char*)inp;
118 int offby = ((char *)p - (char *)0) % (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long));
120 return p + ((sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long)) - offby);
126 * Optimized by brain, these were using integer division and modulus.
127 * We can use logic shifts and logic AND to replace these even divisions
128 * and multiplications, it should be a bit faster (probably not noticably,
129 * but of course, more impressive). Also made these inline.
132 inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input)
134 rr->type = (QueryType)((input[0] << 8) + input[1]);
135 rr->_class = (input[2] << 8) + input[3];
136 rr->ttl = (input[4] << 24) + (input[5] << 16) + (input[6] << 8) + input[7];
137 rr->rdlength = (input[8] << 8) + input[9];
140 inline void dns_fill_header(s_header *header, const unsigned char *input, const int l)
142 header->id[0] = input[0];
143 header->id[1] = input[1];
144 header->flags1 = input[2];
145 header->flags2 = input[3];
146 header->qdcount = (input[4] << 8) + input[5];
147 header->ancount = (input[6] << 8) + input[7];
148 header->nscount = (input[8] << 8) + input[9];
149 header->arcount = (input[10] << 8) + input[11];
150 memcpy(header->payload,&input[12],l);
153 inline void dns_empty_header(unsigned char *output, const s_header *header, const int l)
155 output[0] = header->id[0];
156 output[1] = header->id[1];
157 output[2] = header->flags1;
158 output[3] = header->flags2;
159 output[4] = header->qdcount >> 8;
160 output[5] = header->qdcount & 0xFF;
161 output[6] = header->ancount >> 8;
162 output[7] = header->ancount & 0xFF;
163 output[8] = header->nscount >> 8;
164 output[9] = header->nscount & 0xFF;
165 output[10] = header->arcount >> 8;
166 output[11] = header->arcount & 0xFF;
167 memcpy(&output[12],header->payload,l);
170 void dns_close(int fd)
173 if (ServerInstance && ServerInstance->SE)
174 ServerInstance->SE->DelFd(fd);
176 log(DEBUG,"DNS: dns_close on fd %d",fd);
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 */
296 pthread_mutex_lock(&connmap_lock);
298 if (connections.find(s->fd) == connections.end())
299 connections[s->fd] = s;
301 pthread_mutex_unlock(&connmap_lock);
307 int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload)
310 const char * tempchr, * tempchr2;
316 /* split name up into labels, create query */
317 while ((tempchr = strchr(tempchr2,'.')) != NULL)
319 l = tempchr - tempchr2;
320 if (payloadpos + l + 1 > 507)
322 payload[payloadpos++] = l;
323 memcpy(&payload[payloadpos],tempchr2,l);
325 tempchr2 = &tempchr[1];
327 l = strlen(tempchr2);
330 if (payloadpos + l + 2 > 507)
332 payload[payloadpos++] = l;
333 memcpy(&payload[payloadpos],tempchr2,l);
335 payload[payloadpos++] = '\0';
337 if (payloadpos > 508)
340 memcpy(&payload[payloadpos],&l,2);
342 memcpy(&payload[payloadpos + 2],&l,2);
343 return payloadpos + 4;
346 in_addr* DNS::dns_aton4(const char * const ipstring)
349 return dns_aton4_s(ipstring,&ip);
352 in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
355 if(dns_aton4_s(ipstring,ip) == NULL)
363 in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
364 inet_aton(ipstring,ip);
368 int DNS::dns_getip4(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
376 l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
379 s = dns_add_query(&h);
384 if (dns_send_requests(&h,s,l) == -1)
390 int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retrieve result with dns_getresult() */
397 l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
400 s = dns_add_query(&h);
406 if (dns_send_requests(&h,s,l) == -1)
412 int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
419 c = (unsigned char *)&ip->s_addr;
421 sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
423 l = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char *)&h.payload);
426 s = dns_add_query(&h);
430 s->type = DNS_QRY_PTR;
431 if (dns_send_requests(&h,s,l) == -1)
437 char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
439 return dns_ntoa4_s(ip,r);
442 char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
444 m = (unsigned char *)&ip->s_addr;
445 sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
449 char* DNS::dns_getresult(const int cfd) { /* retrieve result of DNS query */
450 log(DEBUG,"DNS: dns_getresult with cfd=%d",cfd);
451 return dns_getresult_s(cfd,this->localbuf);
454 char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS query (buffered) */
457 int l, i, q, curanswer, o;
459 unsigned char buffer[sizeof(s_header)];
465 /* FireDNS used a linked list for this. How ugly (and slow). */
468 /* XXX: STL really does NOT like being poked and prodded in more than
469 * one orifice by threaded apps. Make sure we remain nice to it, and
470 * lock a mutex around any access to the std::map.
472 pthread_mutex_lock(&connmap_lock);
474 connlist_iter n_iter = connections.find(cfd);
475 if (n_iter == connections.end())
477 log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d",cfd);
482 /* Remove the query from the list */
483 c = (s_connection*)n_iter->second;
484 /* We don't delete c here, because its done later when needed */
485 connections.erase(n_iter);
488 pthread_mutex_unlock(&connmap_lock);
491 l = recv(c->fd,buffer,sizeof(s_header),0);
498 dns_fill_header(&h,buffer,l - 12);
499 if (c->id[0] != h.id[0] || c->id[1] != h.id[1])
501 log(DEBUG,"DNS: id mismatch on query");
503 return NULL; /* ID mismatch */
505 if ((h.flags1 & FLAGS1_MASK_QR) == 0)
507 log(DEBUG,"DNS: didnt get a query result");
511 if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0)
513 log(DEBUG,"DNS: got an OPCODE and didnt want one");
517 if ((h.flags2 & FLAGS2_MASK_RCODE) != 0)
519 log(DEBUG,"DNS lookup failed due to SERVFAIL");
525 log(DEBUG,"DNS: no answers!");
532 while ((unsigned)q < h.qdcount && i < l)
534 if (h.payload[i] > 63)
541 if (h.payload[i] == 0)
546 else i += h.payload[i] + 1;
550 while ((unsigned)curanswer < h.ancount)
553 while (q == 0 && i < l)
555 if (h.payload[i] > 63)
562 if (h.payload[i] == 0)
567 else i += h.payload[i] + 1; /* skip length and label */
575 dns_fill_rr(&rr,&h.payload[i]);
577 if (rr.type != c->type)
583 if (rr._class != c->_class)
591 if ((unsigned)curanswer == h.ancount)
593 if ((unsigned)i + rr.rdlength > (unsigned)l)
595 if (rr.rdlength > 1023)
601 log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
604 while (q == 0 && i < l && o + 256 < 1023)
606 if (h.payload[i] > 63)
608 log(DEBUG,"DNS: h.payload[i] > 63");
609 memcpy(&p,&h.payload[i],2);
610 i = ntohs(p) - 0xC000 - 12;
614 if (h.payload[i] == 0)
623 memcpy(&res[o],&h.payload[i + 1],h.payload[i]);
625 i += h.payload[i] + 1;
632 log(DEBUG,"DNS: got a result of type DNS_QRY_A");
635 dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
636 while ((char *)alist - (char *)res < 700)
638 if (rr.type != DNS_QRY_A)
642 if (rr.rdlength != 4)
647 memcpy(&alist->ip,&h.payload[i],4);
648 if ((unsigned)++curanswer >= h.ancount)
652 while (q == 0 && i < l)
654 if (h.payload[i] > 63)
661 if (h.payload[i] == 0)
666 else i += h.payload[i] + 1;
674 dns_fill_rr(&rr,&h.payload[i]);
676 alist->next = (dns_ip4list *) dns_align(((char *) alist) + sizeof(dns_ip4list));
683 memcpy(res,&h.payload[i],rr.rdlength);
684 res[rr.rdlength] = '\0';
687 memcpy(res,&h.payload[i],rr.rdlength);
688 res[rr.rdlength] = '\0';
698 log(DEBUG,"Create blank DNS");
701 DNS::DNS(const std::string &dnsserver)
703 dns_init_2(dnsserver.c_str());
704 log(DEBUG,"Create DNS with server '%s'",dnsserver.c_str());
707 void DNS::SetNS(const std::string &dnsserver)
709 dns_init_2(dnsserver.c_str());
717 bool DNS::ReverseLookup(const std::string &ip, bool ins)
719 if (ServerInstance && ServerInstance->stats)
720 ServerInstance->stats->statsDns++;
721 binip = dns_aton4(ip.c_str());
727 this->myfd = dns_getname4(binip);
728 if (this->myfd == -1)
732 log(DEBUG,"DNS: ReverseLookup, fd=%d",this->myfd);
736 if (ServerInstance && ServerInstance->SE)
737 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
743 bool DNS::ForwardLookup(const std::string &host, bool ins)
745 if (ServerInstance && ServerInstance->stats)
746 ServerInstance->stats->statsDns++;
747 this->myfd = dns_getip4(host.c_str());
748 if (this->myfd == -1)
752 log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
756 if (ServerInstance && ServerInstance->SE)
757 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
763 bool DNS::ForwardLookupWithFD(const std::string &host, int &fd)
765 if (ServerInstance && ServerInstance->stats)
766 ServerInstance->stats->statsDns++;
767 this->myfd = dns_getip4(host.c_str());
769 if (this->myfd == -1)
773 log(DEBUG,"DNS: ForwardLookupWithFD, fd=%d",this->myfd);
774 if (ServerInstance && ServerInstance->SE)
775 ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_MODULE);
779 bool DNS::HasResult(int fd)
781 return (fd == this->myfd);
784 /* Only the multithreaded dns uses this poll() based
785 * check now. As its in another thread we dont have
786 * to worry about its performance that much.
788 bool DNS::HasResult()
790 log(DEBUG,"DNS: HasResult, fd=%d",this->myfd);
792 polls.fd = this->myfd;
793 polls.events = POLLIN;
794 int ret = poll(&polls,1,1);
795 log(DEBUG,"DNS: Hasresult returning %d",ret);
804 std::string DNS::GetResult()
806 log(DEBUG,"DNS: GetResult()");
807 result = dns_getresult(this->myfd);
810 if (ServerInstance && ServerInstance->stats)
811 ServerInstance->stats->statsDnsGood++;
812 dns_close(this->myfd);
818 if (ServerInstance && ServerInstance->stats)
819 ServerInstance->stats->statsDnsBad++;
820 if (this->myfd != -1)
822 dns_close(this->myfd);
829 std::string DNS::GetResultIP()
832 log(DEBUG,"DNS: GetResultIP()");
833 result = dns_getresult(this->myfd);
834 if (this->myfd != -1)
836 dns_close(this->myfd);
841 if (ServerInstance && ServerInstance->stats)
842 ServerInstance->stats->statsDnsGood++;
843 unsigned char a = (unsigned)result[0];
844 unsigned char b = (unsigned)result[1];
845 unsigned char c = (unsigned)result[2];
846 unsigned char d = (unsigned)result[3];
847 snprintf(r,1024,"%u.%u.%u.%u",a,b,c,d);
852 if (ServerInstance && ServerInstance->stats)
853 ServerInstance->stats->statsDnsBad++;
854 log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
863 /* This function is a thread function which can be thought of as a lightweight process
864 * to all you non-threaded people. In actuality its so much more, and pretty damn cool.
865 * With threaded dns enabled, each user which connects gets a thread attached to their
866 * user record when their DNS lookup starts. This function starts in parallel, and
867 * commences a blocking dns lookup. Because its a seperate thread, this occurs without
868 * actually blocking the main application. Once the dns lookup is completed, the thread
869 * checks if the user is still around by checking their fd against the reference table,
870 * and if they are, writes the hostname into the struct and terminates, after setting
871 * userrec::dns_done to true. Because this is multi-threaded it can make proper use of
872 * SMP setups (like the one i have here *grin*).
873 * This is in comparison to the non-threaded dns, which must monitor the thread sockets
874 * in a nonblocking fashion, consuming more resources to do so.
876 void* dns_task(void* arg)
878 userrec* u = (userrec*)arg;
881 log(DEBUG,"DNS thread for user %s",u->nick);
886 if (dns1.ReverseLookup(inet_ntoa(u->ip4),false))
888 while (!dns1.HasResult())
890 host = dns1.GetResult();
893 if (dns2.ForwardLookup(host, false))
895 while (!dns2.HasResult())
897 ip = dns2.GetResultIP();
898 if (ip == std::string(inet_ntoa(u->ip4)))
900 if (host.length() < 65)
902 if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
906 strcpy(u->host,host.c_str());
907 if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
909 strcpy(u->dhost,host.c_str());
918 if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
924 Resolver::Resolver(const std::string &source, bool forward, const std::string &dnsserver = "") : input(source), fwd(forward), server(dnsserver)
926 if (this->server != "")
927 Query.SetNS(this->server);
929 Query.SetNS(Config->DNSServer);
933 Query.ForwardLookup(input.c_str(), false);
934 this->fd = Query.GetFD();
938 Query.ReverseLookup(input.c_str(), false);
939 this->fd = Query.GetFD();
943 log(DEBUG,"Resolver::Resolver: RESOLVER_NSDOWN");
944 this->OnError(RESOLVER_NSDOWN);
945 ModuleException e("Resolver: Nameserver is down");
947 /* We shouldnt get here really */
951 if (ServerInstance && ServerInstance->SE)
953 log(DEBUG,"Resolver::Resolver: this->fd=%d",this->fd);
954 ServerInstance->SE->AddFd(this->fd,true,X_ESTAB_CLASSDNS);
958 log(DEBUG,"Resolver::Resolver: RESOLVER_NOTREADY");
959 this->OnError(RESOLVER_NOTREADY);
960 ModuleException e("Resolver: Core not initialized yet");
962 /* We shouldnt get here really */
967 Resolver::~Resolver()
969 log(DEBUG,"Resolver::~Resolver");
970 if (ServerInstance && ServerInstance->SE)
971 ServerInstance->SE->DelFd(this->fd);
974 int Resolver::GetFd()
979 bool Resolver::ProcessResult()
981 log(DEBUG,"Resolver::ProcessResult");
983 result = Query.GetResultIP();
985 result = Query.GetResult();
989 log(DEBUG,"Resolver::OnLookupComplete(%s)",result.c_str());
990 this->OnLookupComplete(result);
995 log(DEBUG,"Resolver::OnError(RESOLVER_NXDOMAIN)");
996 this->OnError(RESOLVER_NXDOMAIN);
1001 void Resolver::OnLookupComplete(const std::string &result)
1005 void Resolver::OnError(ResolverError e)
1009 void dns_deal_with_classes(int fd)
1011 log(DEBUG,"dns_deal_with_classes(%d)",fd);
1012 if ((fd > -1) && (dns_classes[fd]))
1014 log(DEBUG,"Valid fd %d",fd);
1015 dns_classes[fd]->ProcessResult();
1016 delete dns_classes[fd];
1017 dns_classes[fd] = NULL;
1021 bool dns_add_class(Resolver* r)
1023 log(DEBUG,"dns_add_class");
1024 if ((r) && (r->GetFd() > -1))
1026 if (!dns_classes[r->GetFd()])
1028 log(DEBUG,"dns_add_class: added class");
1029 dns_classes[r->GetFd()] = r;
1034 log(DEBUG,"Space occupied!");
1040 log(DEBUG,"Bad class");
1048 memset(dns_classes,0,sizeof(dns_classes));