-/*
-dns.cpp - based on the firedns library Copyright (C) 2002 Ian Gulliver
-
-This program is free software; you can redistribute it and/or modify
-it under the terms of version 2 of the GNU General Public License as
-published by the Free Software Foundation.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+/* +------------------------------------+
+ * | Inspire Internet Relay Chat Daemon |
+ * +------------------------------------+
+ *
+ * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev.
+ * E-mail:
+ * <brain@chatspike.net>
+ * <Craig@chatspike.net>
+ *
+ * Written by Craig Edwards, Craig McLure, and others.
+ * This program is free but copyrighted software; see
+ * the file COPYING for details.
+ *
+ * ---------------------------------------------------
+ */
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+/*
+dns.cpp - Nonblocking DNS functions.
+Very loosely based on the firedns library,
+Copyright (C) 2002 Ian Gulliver.
+
+There have been so many modifications to this file
+to make it fit into InspIRCd and make it object
+orientated that you should not take this code as
+being what firedns really looks like. It used to
+look very different to this! :-P
*/
-#define _DNS_C
-
using namespace std;
#include <string>
#include "dns.h"
#include "inspircd.h"
#include "helperfuncs.h"
+#include "inspircd_config.h"
#include "socketengine.h"
+#include "configreader.h"
+
+#ifdef THREADED_DNS
+pthread_mutex_t connmap_lock = PTHREAD_MUTEX_INITIALIZER;
+#endif
extern InspIRCd* ServerInstance;
extern ServerConfig* Config;
extern time_t TIME;
+extern userrec* fd_ref_table[MAX_DESCRIPTORS];
enum QueryType { DNS_QRY_A = 1, DNS_QRY_PTR = 12 };
enum QueryFlags1 { FLAGS1_MASK_RD = 0x01, FLAGS1_MASK_TC = 0x02, FLAGS1_MASK_AA = 0x04, FLAGS1_MASK_OPCODE = 0x78, FLAGS1_MASK_QR = 0x80 };
typedef connlist::iterator connlist_iter;
connlist connections;
-struct in_addr servers4[8];
+Resolver* dns_classes[MAX_DESCRIPTORS];
+
+insp_inaddr servers4[8];
int i4;
int initdone = 0;
-int wantclose = 0;
int lastcreate = -1;
class s_connection
};
-void *dns_align(void *inp) {
+void *dns_align(void *inp)
+{
char *p = (char*)inp;
int offby = ((char *)p - (char *)0) % (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long));
if (offby != 0)
* but of course, more impressive). Also made these inline.
*/
-inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
+inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input)
+{
rr->type = (QueryType)((input[0] << 8) + input[1]);
rr->_class = (input[2] << 8) + input[3];
rr->ttl = (input[4] << 24) + (input[5] << 16) + (input[6] << 8) + input[7];
rr->rdlength = (input[8] << 8) + input[9];
}
-inline void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
+inline void dns_fill_header(s_header *header, const unsigned char *input, const int l)
+{
header->id[0] = input[0];
header->id[1] = input[1];
header->flags1 = input[2];
memcpy(header->payload,&input[12],l);
}
-inline void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
+inline void dns_empty_header(unsigned char *output, const s_header *header, const int l)
+{
output[0] = header->id[0];
output[1] = header->id[1];
output[2] = header->flags1;
memcpy(&output[12],header->payload,l);
}
-void dns_close(int fd) { /* close query */
+void dns_close(int fd)
+{
#ifndef THREADED_DNS
- ServerInstance->SE->DelFd(fd);
+ if (ServerInstance && ServerInstance->SE)
+ ServerInstance->SE->DelFd(fd);
#endif
log(DEBUG,"DNS: dns_close on fd %d",fd);
- if (fd == lastcreate) {
- wantclose = 1;
- return;
- }
shutdown(fd,2);
close(fd);
return;
}
-void DNS::dns_init() {
+void DNS::dns_init()
+{
FILE *f;
int i;
- in_addr addr4;
+ insp_inaddr addr4;
char buf[1024];
if (initdone == 1)
return;
initdone = 1;
srand((unsigned int) TIME);
- memset(servers4,'\0',sizeof(in_addr) * 8);
+ memset(servers4,'\0',sizeof(insp_inaddr) * 8);
f = fopen("/etc/resolv.conf","r");
if (f == NULL)
return;
while (fgets(buf,1024,f) != NULL) {
- if (strncmp(buf,"nameserver",10) == 0) {
+ if (strncmp(buf,"nameserver",10) == 0)
+ {
i = 10;
while (buf[i] == ' ' || buf[i] == '\t')
i++;
- if (i4 < 8) {
+ if (i4 < 8)
+ {
if (dns_aton4_s(&buf[i],&addr4) != NULL)
- memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
+ memcpy(&servers4[i4++],&addr4,sizeof(insp_inaddr));
}
}
}
void DNS::dns_init_2(const char* dnsserver)
{
- in_addr addr4;
- i4 = 0;
- srand((unsigned int) TIME);
- memset(servers4,'\0',sizeof(in_addr) * 8);
- if (dns_aton4_s(dnsserver,&addr4) != NULL)
- memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
+ insp_inaddr addr4;
+ i4 = 0;
+ srand((unsigned int) TIME);
+ memset(servers4,'\0',sizeof(insp_inaddr) * 8);
+ if (dns_aton4_s(dnsserver,&addr4) != NULL)
+ memcpy(&servers4[i4++],&addr4,sizeof(insp_inaddr));
}
-static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
+int dns_send_requests(const s_header *h, const s_connection *s, const int l)
{
int i;
- sockaddr_in addr4;
+ insp_sockaddr addr4;
unsigned char payload[sizeof(s_header)];
dns_empty_header(payload,h,l);
return 0;
}
-static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
+s_connection *dns_add_query(s_header *h)
+{
s_connection * s = new s_connection;
int id = rand() % 65536;
h->ancount = 0;
h->nscount = 0;
h->arcount = 0;
-
- /* turn off want_list by default */
s->want_list = 0;
-
- /* try to create ipv6 or ipv4 socket */
- s->fd = socket(PF_INET, SOCK_DGRAM, 0);
- if (s->fd != -1) {
- if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
- shutdown(s->fd,2);
- close(s->fd);
- s->fd = -1;
- }
- }
- if (s->fd != -1) {
- sockaddr_in addr;
- memset(&addr,0,sizeof(addr));
- addr.sin_family = AF_INET;
- addr.sin_port = 0;
- addr.sin_addr.s_addr = INADDR_ANY;
- if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
- shutdown(s->fd,2);
- close(s->fd);
- s->fd = -1;
- }
+ s->fd = socket(PF_INET, SOCK_DGRAM, 0);
+ if (s->fd != -1)
+ {
+ if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0)
+ {
+ shutdown(s->fd,2);
+ close(s->fd);
+ s->fd = -1;
}
- if (s->fd == -1) {
- delete s;
- return NULL;
+ }
+ if (s->fd != -1)
+ {
+ insp_sockaddr addr;
+ memset(&addr,0,sizeof(addr));
+ addr.sin_family = AF_INET;
+ addr.sin_port = 0;
+ addr.sin_addr.s_addr = INADDR_ANY;
+ if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0)
+ {
+ shutdown(s->fd,2);
+ close(s->fd);
+ s->fd = -1;
}
+ }
+ if (s->fd == -1)
+ {
+ DELETE(s);
+ return NULL;
+ }
/* create new connection object, add to linked list */
+#ifdef THREADED_DNS
+ pthread_mutex_lock(&connmap_lock);
+#endif
if (connections.find(s->fd) == connections.end())
connections[s->fd] = s;
+#ifdef THREADED_DNS
+ pthread_mutex_unlock(&connmap_lock);
+#endif
- if (wantclose == 1) {
- shutdown(lastcreate,2);
- close(lastcreate);
- wantclose = 0;
- }
- lastcreate = s->fd;
return s;
}
-static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
+int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload)
+{
short payloadpos;
const char * tempchr, * tempchr2;
unsigned short l;
tempchr2 = name;
/* split name up into labels, create query */
- while ((tempchr = strchr(tempchr2,'.')) != NULL) {
+ while ((tempchr = strchr(tempchr2,'.')) != NULL)
+ {
l = tempchr - tempchr2;
if (payloadpos + l + 1 > 507)
return -1;
tempchr2 = &tempchr[1];
}
l = strlen(tempchr2);
- if (l) {
+ if (l)
+ {
if (payloadpos + l + 2 > 507)
return -1;
payload[payloadpos++] = l;
return payloadpos + 4;
}
-in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
- static in_addr ip;
+insp_inaddr* DNS::dns_aton4(const char * const ipstring)
+{
+ static insp_inaddr ip;
return dns_aton4_s(ipstring,&ip);
}
-in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
- in_addr* ip;
- ip = new in_addr;
- if(dns_aton4_s(ipstring,ip) == NULL) {
- delete ip;
+insp_inaddr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
+ insp_inaddr* ip;
+ ip = new insp_inaddr;
+ if(dns_aton4_s(ipstring,ip) == NULL)
+ {
+ DELETE(ip);
return NULL;
}
return ip;
}
-in_addr* DNS::dns_aton4_s(const char *ipstring, in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
+insp_inaddr* DNS::dns_aton4_s(const char *ipstring, insp_inaddr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
inet_aton(ipstring,ip);
return ip;
}
dns_init();
-
l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
return s->fd;
}
-int DNS::dns_getname4(const in_addr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
+int DNS::dns_getname4(const insp_inaddr *ip) { /* build, add and send PTR query; retrieve result with dns_getresult() */
char query[512];
s_header h;
s_connection * s;
return s->fd;
}
-char* DNS::dns_ntoa4(const in_addr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
+char* DNS::dns_ntoa4(const insp_inaddr * const ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
static char r[256];
return dns_ntoa4_s(ip,r);
}
-char* DNS::dns_ntoa4_s(const in_addr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
+char* DNS::dns_ntoa4_s(const insp_inaddr *ip, char *r) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
unsigned char *m;
m = (unsigned char *)&ip->s_addr;
sprintf(r,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
*res = 0;
/* FireDNS used a linked list for this. How ugly (and slow). */
+
+#ifdef THREADED_DNS
+ /* XXX: STL really does NOT like being poked and prodded in more than
+ * one orifice by threaded apps. Make sure we remain nice to it, and
+ * lock a mutex around any access to the std::map.
+ */
+ pthread_mutex_lock(&connmap_lock);
+#endif
connlist_iter n_iter = connections.find(cfd);
if (n_iter == connections.end())
{
log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d",cfd);
+#ifdef THREADED_DNS
+ pthread_mutex_unlock(&connmap_lock);
+#endif
return NULL;
}
else
/* We don't delete c here, because its done later when needed */
connections.erase(n_iter);
}
+#ifdef THREADED_DNS
+ pthread_mutex_unlock(&connmap_lock);
+#endif
l = recv(c->fd,buffer,sizeof(s_header),0);
dns_close(c->fd);
- if (l < 12) {
- delete c;
+ if (l < 12)
+ {
+ DELETE(c);
return NULL;
}
dns_fill_header(&h,buffer,l - 12);
- if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
+ if (c->id[0] != h.id[0] || c->id[1] != h.id[1])
+ {
log(DEBUG,"DNS: id mismatch on query");
- delete c;
+ DELETE(c);
return NULL; /* ID mismatch */
}
- if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
+ if ((h.flags1 & FLAGS1_MASK_QR) == 0)
+ {
log(DEBUG,"DNS: didnt get a query result");
- delete c;
+ DELETE(c);
return NULL;
}
- if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
+ if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0)
+ {
log(DEBUG,"DNS: got an OPCODE and didnt want one");
- delete c;
+ DELETE(c);
return NULL;
}
- if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
+ if ((h.flags2 & FLAGS2_MASK_RCODE) != 0)
+ {
log(DEBUG,"DNS lookup failed due to SERVFAIL");
- delete c;
+ DELETE(c);
return NULL;
}
- if (h.ancount < 1) { /* no sense going on if we don't have any answers */
+ if (h.ancount < 1)
+ {
log(DEBUG,"DNS: no answers!");
- delete c;
+ DELETE(c);
return NULL;
}
- /* skip queries */
i = 0;
q = 0;
l -= 12;
- while ((unsigned)q < h.qdcount && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 6; /* skip pointer, _class and type */
+ while ((unsigned)q < h.qdcount && i < l)
+ {
+ if (h.payload[i] > 63)
+ {
+ i += 6;
q++;
- } else { /* label */
- if (h.payload[i] == 0) {
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
q++;
- i += 5; /* skip nil, _class and type */
- } else
- i += h.payload[i] + 1; /* skip length and label */
+ i += 5;
+ }
+ else i += h.payload[i] + 1;
}
}
- /* &h.payload[i] should now be the start of the first response */
curanswer = 0;
- while ((unsigned)curanswer < h.ancount) {
+ while ((unsigned)curanswer < h.ancount)
+ {
q = 0;
- while (q == 0 && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 2; /* skip pointer */
+ while (q == 0 && i < l)
+ {
+ if (h.payload[i] > 63)
+ {
+ i += 2;
q = 1;
- } else { /* label */
- if (h.payload[i] == 0) {
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
i++;
q = 1;
- } else
- i += h.payload[i] + 1; /* skip length and label */
+ }
+ else i += h.payload[i] + 1; /* skip length and label */
}
}
- if (l - i < 10) {
- delete c;
+ if (l - i < 10)
+ {
+ DELETE(c);
return NULL;
}
dns_fill_rr(&rr,&h.payload[i]);
i += 10;
- if (rr.type != c->type) {
+ if (rr.type != c->type)
+ {
curanswer++;
i += rr.rdlength;
continue;
}
- if (rr._class != c->_class) {
+ if (rr._class != c->_class)
+ {
curanswer++;
i += rr.rdlength;
continue;
if (rr.rdlength > 1023)
return NULL;
- switch (rr.type) {
+ switch (rr.type)
+ {
case DNS_QRY_PTR:
log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
o = 0;
q = 0;
- while (q == 0 && i < l && o + 256 < 1023) {
- if (h.payload[i] > 63) { /* pointer */
+ while (q == 0 && i < l && o + 256 < 1023)
+ {
+ if (h.payload[i] > 63)
+ {
+ log(DEBUG,"DNS: h.payload[i] > 63");
memcpy(&p,&h.payload[i],2);
i = ntohs(p) - 0xC000 - 12;
- } else { /* label */
+ }
+ else
+ {
if (h.payload[i] == 0)
+ {
q = 1;
- else {
+ }
+ else
+ {
res[o] = '\0';
if (o != 0)
res[o++] = '.';
}
}
res[o] = '\0';
- break;
+ break;
case DNS_QRY_A:
log(DEBUG,"DNS: got a result of type DNS_QRY_A");
- if (c->want_list) {
+ if (c->want_list)
+ {
dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
- while ((char *)alist - (char *)res < 700) {
+ while ((char *)alist - (char *)res < 700)
+ {
if (rr.type != DNS_QRY_A)
break;
if (rr._class != 1)
break;
- if (rr.rdlength != 4) {
- delete c;
+ if (rr.rdlength != 4)
+ {
+ DELETE(c);
return NULL;
}
memcpy(&alist->ip,&h.payload[i],4);
if ((unsigned)++curanswer >= h.ancount)
break;
i += rr.rdlength;
+ q = 0;
+ while (q == 0 && i < l)
{
- /* skip next name */
- q = 0;
- while (q == 0 && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 2; /* skip pointer */
+ if (h.payload[i] > 63)
+ {
+ i += 2;
+ q = 1;
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
+ i++;
q = 1;
- } else { /* label */
- if (h.payload[i] == 0) {
- i++;
- q = 1;
- } else
- i += h.payload[i] + 1; /* skip length and label */
}
+ else i += h.payload[i] + 1;
}
}
- if (l - i < 10) {
- delete c;
+ if (l - i < 10)
+ {
+ DELETE(c);
return NULL;
}
dns_fill_rr(&rr,&h.payload[i]);
alist->next = NULL;
break;
}
- goto defaultcase;
+ memcpy(res,&h.payload[i],rr.rdlength);
+ res[rr.rdlength] = '\0';
break;
default:
- defaultcase:
- log(DEBUG,"DNS: doing something with result 'default'");
memcpy(res,&h.payload[i],rr.rdlength);
res[rr.rdlength] = '\0';
break;
}
- delete c;
+ DELETE(c);
return res;
}
log(DEBUG,"Create blank DNS");
}
-DNS::DNS(std::string dnsserver)
+DNS::DNS(const std::string &dnsserver)
{
dns_init_2(dnsserver.c_str());
- log(DEBUG,"Create DNS");
+ log(DEBUG,"Create DNS with server '%s'",dnsserver.c_str());
}
-void DNS::SetNS(std::string dnsserver)
+void DNS::SetNS(const std::string &dnsserver)
{
dns_init_2(dnsserver.c_str());
log(DEBUG,"Set NS");
{
}
-bool DNS::ReverseLookup(std::string ip)
+bool DNS::ReverseLookup(const std::string &ip, bool ins)
{
- ServerInstance->stats->statsDns++;
- binip = dns_aton4(ip.c_str());
- if (binip == NULL) {
- return false;
- }
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDns++;
+ binip = dns_aton4(ip.c_str());
+ if (binip == NULL)
+ {
+ return false;
+ }
- this->myfd = dns_getname4(binip);
+ this->myfd = dns_getname4(binip);
if (this->myfd == -1)
{
return false;
}
log(DEBUG,"DNS: ReverseLookup, fd=%d",this->myfd);
#ifndef THREADED_DNS
- ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
+ if (ins)
+ {
+ if (ServerInstance && ServerInstance->SE)
+ ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
+ }
#endif
return true;
}
-bool DNS::ForwardLookup(std::string host)
+bool DNS::ForwardLookup(const std::string &host, bool ins)
{
- ServerInstance->stats->statsDns++;
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDns++;
this->myfd = dns_getip4(host.c_str());
if (this->myfd == -1)
{
}
log(DEBUG,"DNS: ForwardLookup, fd=%d",this->myfd);
#ifndef THREADED_DNS
- ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
+ if (ins)
+ {
+ if (ServerInstance && ServerInstance->SE)
+ ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_DNS);
+ }
#endif
return true;
}
+bool DNS::ForwardLookupWithFD(const std::string &host, int &fd)
+{
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDns++;
+ this->myfd = dns_getip4(host.c_str());
+ fd = this->myfd;
+ if (this->myfd == -1)
+ {
+ return false;
+ }
+ log(DEBUG,"DNS: ForwardLookupWithFD, fd=%d",this->myfd);
+ if (ServerInstance && ServerInstance->SE)
+ ServerInstance->SE->AddFd(this->myfd,true,X_ESTAB_MODULE);
+ return true;
+}
+
bool DNS::HasResult(int fd)
{
return (fd == this->myfd);
std::string DNS::GetResult()
{
log(DEBUG,"DNS: GetResult()");
- result = dns_getresult(this->myfd);
- if (result) {
- ServerInstance->stats->statsDnsGood++;
+ result = dns_getresult(this->myfd);
+ if (result)
+ {
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDnsGood++;
dns_close(this->myfd);
+ this->myfd = -1;
return result;
- } else {
- ServerInstance->stats->statsDnsBad++;
+ }
+ else
+ {
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDnsBad++;
if (this->myfd != -1)
{
dns_close(this->myfd);
+ this->myfd = -1;
}
return "";
}
if (this->myfd != -1)
{
dns_close(this->myfd);
+ this->myfd = -1;
}
if (result)
{
- ServerInstance->stats->statsDnsGood++;
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDnsGood++;
unsigned char a = (unsigned)result[0];
unsigned char b = (unsigned)result[1];
unsigned char c = (unsigned)result[2];
}
else
{
- ServerInstance->stats->statsDnsBad++;
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDnsBad++;
log(DEBUG,"DANGER WILL ROBINSON! NXDOMAIN for forward lookup, but we got a reverse lookup!");
return "";
}
#ifdef THREADED_DNS
+
+/* This function is a thread function which can be thought of as a lightweight process
+ * to all you non-threaded people. In actuality its so much more, and pretty damn cool.
+ * With threaded dns enabled, each user which connects gets a thread attached to their
+ * user record when their DNS lookup starts. This function starts in parallel, and
+ * commences a blocking dns lookup. Because its a seperate thread, this occurs without
+ * actually blocking the main application. Once the dns lookup is completed, the thread
+ * checks if the user is still around by checking their fd against the reference table,
+ * and if they are, writes the hostname into the struct and terminates, after setting
+ * userrec::dns_done to true. Because this is multi-threaded it can make proper use of
+ * SMP setups (like the one i have here *grin*).
+ * This is in comparison to the non-threaded dns, which must monitor the thread sockets
+ * in a nonblocking fashion, consuming more resources to do so.
+ *
+ * NB: Yes this does scale, thank you. Even with large numbers of connecting clients
+ * in any one timeframe, they wont all connect *at the same time* therefore any argument
+ * of "but there will be thousands of threads it'll blow up" is moot, ive tested this and
+ * there will only ever be somewhere around the listen backlog in number of pending
+ * lookups at any one time. This is significant on any modern SMP system.
+ */
void* dns_task(void* arg)
{
- userrec* u = (userrec*)arg;
- log(DEBUG,"DNS thread for user %s",u->nick);
- DNS dns1;
- DNS dns2;
- std::string host;
- std::string ip;
- if (dns1.ReverseLookup(u->ip))
- {
- while (!dns1.HasResult())
- {
- usleep(100);
- }
- host = dns1.GetResult();
- if (host != "")
- {
- if (dns2.ForwardLookup(host))
- {
- while (!dns2.HasResult())
- {
- usleep(100);
- }
- ip = dns2.GetResultIP();
- if (ip == std::string(u->ip))
- {
- if (host.length() < 160)
- {
- strcpy(u->host,host.c_str());
- strcpy(u->dhost,host.c_str());
- }
- }
- }
- }
- }
- u->dns_done = true;
- return NULL;
+ userrec* u = (userrec*)arg;
+ int thisfd = u->fd;
+
+ log(DEBUG,"DNS thread for user %s",u->nick);
+ DNS dns1(Config->DNSServer);
+ DNS dns2(Config->DNSServer);
+ std::string host;
+ std::string ip;
+ int iterations = 0;
+
+ if (dns1.ReverseLookup(inet_ntoa(u->ip4),false))
+ {
+ /* FIX: Dont make these infinite! */
+ while ((!dns1.HasResult()) && (++iterations < 20))
+ usleep(100);
+
+ if (iterations < 20)
+ {
+ if (dns1.GetFD() != -1)
+ {
+ host = dns1.GetResult();
+ if (host != "")
+ {
+ if (dns2.ForwardLookup(host, false))
+ {
+ iterations = 0;
+ while ((!dns2.HasResult()) && (++iterations < 20))
+ usleep(100);
+
+ if (iterations < 20)
+ {
+ if (dns2.GetFD() != -1)
+ {
+ ip = dns2.GetResultIP();
+ if (ip == std::string(inet_ntoa(u->ip4)))
+ {
+ if (host.length() < 65)
+ {
+ if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
+ {
+ if (!u->dns_done)
+ {
+ strcpy(u->host,host.c_str());
+ if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
+ {
+ strcpy(u->dhost,host.c_str());
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ if ((fd_ref_table[thisfd] == u) && (fd_ref_table[thisfd]))
+ u->dns_done = true;
+ log(DEBUG,"THREAD EXIT");
+ return NULL;
}
#endif
+
+Resolver::Resolver(const std::string &source, bool forward, const std::string &dnsserver = "") : input(source), fwd(forward), server(dnsserver)
+{
+ if (this->server != "")
+ Query.SetNS(this->server);
+ else
+ Query.SetNS(Config->DNSServer);
+
+ if (forward)
+ {
+ Query.ForwardLookup(input.c_str(), false);
+ this->fd = Query.GetFD();
+ }
+ else
+ {
+ Query.ReverseLookup(input.c_str(), false);
+ this->fd = Query.GetFD();
+ }
+ if (fd < 0)
+ {
+ log(DEBUG,"Resolver::Resolver: RESOLVER_NSDOWN");
+ this->OnError(RESOLVER_NSDOWN);
+ ModuleException e("Resolver: Nameserver is down");
+ throw e;
+ /* We shouldnt get here really */
+ return;
+ }
+
+ if (ServerInstance && ServerInstance->SE)
+ {
+ log(DEBUG,"Resolver::Resolver: this->fd=%d",this->fd);
+ ServerInstance->SE->AddFd(this->fd,true,X_ESTAB_CLASSDNS);
+ }
+ else
+ {
+ log(DEBUG,"Resolver::Resolver: RESOLVER_NOTREADY");
+ this->OnError(RESOLVER_NOTREADY);
+ ModuleException e("Resolver: Core not initialized yet");
+ throw e;
+ /* We shouldnt get here really */
+ return;
+ }
+}
+
+Resolver::~Resolver()
+{
+ log(DEBUG,"Resolver::~Resolver");
+ if (ServerInstance && ServerInstance->SE)
+ ServerInstance->SE->DelFd(this->fd);
+}
+
+int Resolver::GetFd()
+{
+ return this->fd;
+}
+
+bool Resolver::ProcessResult()
+{
+ log(DEBUG,"Resolver::ProcessResult");
+ if (this->fwd)
+ result = Query.GetResultIP();
+ else
+ result = Query.GetResult();
+
+ if (result != "")
+ {
+ log(DEBUG,"Resolver::OnLookupComplete(%s)",result.c_str());
+ this->OnLookupComplete(result);
+ return true;
+ }
+ else
+ {
+ log(DEBUG,"Resolver::OnError(RESOLVER_NXDOMAIN)");
+ this->OnError(RESOLVER_NXDOMAIN);
+ return false;
+ }
+}
+
+void Resolver::OnLookupComplete(const std::string &result)
+{
+}
+
+void Resolver::OnError(ResolverError e)
+{
+}
+
+void dns_deal_with_classes(int fd)
+{
+ log(DEBUG,"dns_deal_with_classes(%d)",fd);
+ if ((fd > -1) && (dns_classes[fd]))
+ {
+ log(DEBUG,"Valid fd %d",fd);
+ dns_classes[fd]->ProcessResult();
+ delete dns_classes[fd];
+ dns_classes[fd] = NULL;
+ }
+}
+
+bool dns_add_class(Resolver* r)
+{
+ log(DEBUG,"dns_add_class");
+ if ((r) && (r->GetFd() > -1))
+ {
+ if (!dns_classes[r->GetFd()])
+ {
+ log(DEBUG,"dns_add_class: added class");
+ dns_classes[r->GetFd()] = r;
+ return true;
+ }
+ else
+ {
+ log(DEBUG,"Space occupied!");
+ return false;
+ }
+ }
+ else
+ {
+ log(DEBUG,"Bad class");
+ delete r;
+ return true;
+ }
+}
+
+void init_dns()
+{
+ memset(dns_classes,0,sizeof(dns_classes));
+}
+