summaryrefslogtreecommitdiff
path: root/src/dns.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'src/dns.cpp')
-rw-r--r--src/dns.cpp1120
1 files changed, 0 insertions, 1120 deletions
diff --git a/src/dns.cpp b/src/dns.cpp
deleted file mode 100644
index 3d3bc947f..000000000
--- a/src/dns.cpp
+++ /dev/null
@@ -1,1120 +0,0 @@
-/*
- * InspIRCd -- Internet Relay Chat Daemon
- *
- * Copyright (C) 2012 William Pitcock <nenolod@dereferenced.org>
- * Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
- * Copyright (C) 2006, 2009 Robin Burchell <robin+git@viroteck.net>
- * Copyright (C) 2007, 2009 Dennis Friis <peavey@inspircd.org>
- * Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
- * Copyright (C) 2005-2007 Craig Edwards <craigedwards@brainbox.cc>
- *
- * This file is part of InspIRCd. InspIRCd is free software: you can
- * redistribute it and/or modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation, version 2.
- *
- * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-
-/* $Core */
-
-/*
-dns.cpp - Nonblocking DNS functions.
-Very very loosely based on the firedns library,
-Copyright (C) 2002 Ian Gulliver. This file is no
-longer anything like firedns, there are many major
-differences between this code and the original.
-Please do not assume that firedns works like this,
-looks like this, walks like this or tastes like this.
-*/
-
-#ifndef _WIN32
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <errno.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#else
-#include "inspircd_win32wrapper.h"
-#endif
-
-#include "inspircd.h"
-#include "socketengine.h"
-#include "configreader.h"
-#include "socket.h"
-
-#define DN_COMP_BITMASK 0xC000 /* highest 6 bits in a DN label header */
-
-/** Masks to mask off the responses we get from the DNSRequest methods
- */
-enum QueryInfo
-{
- ERROR_MASK = 0x10000 /* Result is an error */
-};
-
-/** Flags which can be ORed into a request or reply for different meanings
- */
-enum QueryFlags
-{
- FLAGS_MASK_RD = 0x01, /* Recursive */
- FLAGS_MASK_TC = 0x02,
- FLAGS_MASK_AA = 0x04, /* Authoritative */
- FLAGS_MASK_OPCODE = 0x78,
- FLAGS_MASK_QR = 0x80,
- FLAGS_MASK_RCODE = 0x0F, /* Request */
- FLAGS_MASK_Z = 0x70,
- FLAGS_MASK_RA = 0x80
-};
-
-
-/** Represents a dns resource record (rr)
- */
-struct ResourceRecord
-{
- QueryType type; /* Record type */
- unsigned int rr_class; /* Record class */
- unsigned long ttl; /* Time to live */
- unsigned int rdlength; /* Record length */
-};
-
-/** Represents a dns request/reply header, and its payload as opaque data.
- */
-class DNSHeader
-{
- public:
- unsigned char id[2]; /* Request id */
- unsigned int flags1; /* Flags */
- unsigned int flags2; /* Flags */
- unsigned int qdcount;
- unsigned int ancount; /* Answer count */
- unsigned int nscount; /* Nameserver count */
- unsigned int arcount;
- unsigned char payload[512]; /* Packet payload */
-};
-
-class DNSRequest
-{
- public:
- unsigned char id[2]; /* Request id */
- unsigned char* res; /* Result processing buffer */
- unsigned int rr_class; /* Request class */
- QueryType type; /* Request type */
- DNS* dnsobj; /* DNS caller (where we get our FD from) */
- unsigned long ttl; /* Time to live */
- std::string orig; /* Original requested name/ip */
-
- DNSRequest(DNS* dns, int id, const std::string &original);
- ~DNSRequest();
- DNSInfo ResultIsReady(DNSHeader &h, unsigned length);
- int SendRequests(const DNSHeader *header, const int length, QueryType qt);
-};
-
-class CacheTimer : public Timer
-{
- private:
- DNS* dns;
- public:
- CacheTimer(DNS* thisdns)
- : Timer(5*60, ServerInstance->Time(), true), dns(thisdns) { }
-
- virtual void Tick(time_t)
- {
- dns->PruneCache();
- }
-};
-
-class RequestTimeout : public Timer
-{
- DNSRequest* watch;
- int watchid;
- public:
- RequestTimeout(unsigned long n, DNSRequest* watching, int id) : Timer(n, ServerInstance->Time()), watch(watching), watchid(id)
- {
- }
- ~RequestTimeout()
- {
- if (ServerInstance->Res)
- Tick(0);
- }
-
- void Tick(time_t)
- {
- if (ServerInstance->Res->requests[watchid] == watch)
- {
- /* Still exists, whack it */
- if (ServerInstance->Res->Classes[watchid])
- {
- ServerInstance->Res->Classes[watchid]->OnError(RESOLVER_TIMEOUT, "Request timed out");
- delete ServerInstance->Res->Classes[watchid];
- ServerInstance->Res->Classes[watchid] = NULL;
- }
- ServerInstance->Res->requests[watchid] = NULL;
- delete watch;
- }
- }
-};
-
-CachedQuery::CachedQuery(const std::string &res, QueryType qt, unsigned int ttl) : data(res), type(qt)
-{
- if (ttl > 5*60)
- ttl = 5*60;
- expires = ServerInstance->Time() + ttl;
-}
-
-int CachedQuery::CalcTTLRemaining()
-{
- int n = expires - ServerInstance->Time();
- return (n < 0 ? 0 : n);
-}
-
-/* Allocate the processing buffer */
-DNSRequest::DNSRequest(DNS* dns, int rid, const std::string &original) : dnsobj(dns)
-{
- /* hardening against overflow here: make our work buffer twice the theoretical
- * maximum size so that hostile input doesn't screw us over.
- */
- res = new unsigned char[sizeof(DNSHeader) * 2];
- *res = 0;
- orig = original;
- RequestTimeout* RT = new RequestTimeout(ServerInstance->Config->dns_timeout ? ServerInstance->Config->dns_timeout : 5, this, rid);
- ServerInstance->Timers->AddTimer(RT); /* The timer manager frees this */
-}
-
-/* Deallocate the processing buffer */
-DNSRequest::~DNSRequest()
-{
- delete[] res;
-}
-
-/** Fill a ResourceRecord class based on raw data input */
-inline void DNS::FillResourceRecord(ResourceRecord* rr, const unsigned char *input)
-{
- rr->type = (QueryType)((input[0] << 8) + input[1]);
- rr->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];
-}
-
-/** Fill a DNSHeader class based on raw data input of a given length */
-inline void DNS::FillHeader(DNSHeader *header, const unsigned char *input, const int length)
-{
- header->id[0] = input[0];
- header->id[1] = input[1];
- header->flags1 = input[2];
- header->flags2 = input[3];
- header->qdcount = (input[4] << 8) + input[5];
- header->ancount = (input[6] << 8) + input[7];
- header->nscount = (input[8] << 8) + input[9];
- header->arcount = (input[10] << 8) + input[11];
- memcpy(header->payload,&input[12],length);
-}
-
-/** Empty a DNSHeader class out into raw data, ready for transmission */
-inline void DNS::EmptyHeader(unsigned char *output, const DNSHeader *header, const int length)
-{
- output[0] = header->id[0];
- output[1] = header->id[1];
- output[2] = header->flags1;
- output[3] = header->flags2;
- output[4] = header->qdcount >> 8;
- output[5] = header->qdcount & 0xFF;
- output[6] = header->ancount >> 8;
- output[7] = header->ancount & 0xFF;
- output[8] = header->nscount >> 8;
- output[9] = header->nscount & 0xFF;
- output[10] = header->arcount >> 8;
- output[11] = header->arcount & 0xFF;
- memcpy(&output[12],header->payload,length);
-}
-
-/** Send requests we have previously built down the UDP socket */
-int DNSRequest::SendRequests(const DNSHeader *header, const int length, QueryType qt)
-{
- ServerInstance->Logs->Log("RESOLVER", DEBUG,"DNSRequest::SendRequests");
-
- unsigned char payload[sizeof(DNSHeader)];
-
- this->rr_class = 1;
- this->type = qt;
-
- DNS::EmptyHeader(payload,header,length);
-
- if (ServerInstance->SE->SendTo(dnsobj, payload, length + 12, 0, &(dnsobj->myserver.sa), sa_size(dnsobj->myserver)) != length+12)
- return -1;
-
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Sent OK");
- return 0;
-}
-
-/** Add a query with a predefined header, and allocate an ID for it. */
-DNSRequest* DNS::AddQuery(DNSHeader *header, int &id, const char* original)
-{
- /* Is the DNS connection down? */
- if (this->GetFd() == -1)
- return NULL;
-
- /* Create an id */
- unsigned int tries = 0;
- do {
- id = ServerInstance->GenRandomInt(DNS::MAX_REQUEST_ID);
- if (++tries == DNS::MAX_REQUEST_ID*5)
- {
- // If we couldn't find an empty slot this many times, do a sequential scan as a last
- // resort. If an empty slot is found that way, go on, otherwise throw an exception
- id = -1;
- for (int i = 0; i < DNS::MAX_REQUEST_ID; i++)
- {
- if (!requests[i])
- {
- id = i;
- break;
- }
- }
-
- if (id == -1)
- throw ModuleException("DNS: All ids are in use");
-
- break;
- }
- } while (requests[id]);
-
- DNSRequest* req = new DNSRequest(this, id, original);
-
- header->id[0] = req->id[0] = id >> 8;
- header->id[1] = req->id[1] = id & 0xFF;
- header->flags1 = FLAGS_MASK_RD;
- header->flags2 = 0;
- header->qdcount = 1;
- header->ancount = 0;
- header->nscount = 0;
- header->arcount = 0;
-
- /* At this point we already know the id doesnt exist,
- * so there needs to be no second check for the ::end()
- */
- requests[id] = req;
-
- /* According to the C++ spec, new never returns NULL. */
- return req;
-}
-
-int DNS::ClearCache()
-{
- /* This ensures the buckets are reset to sane levels */
- int rv = this->cache->size();
- delete this->cache;
- this->cache = new dnscache();
- return rv;
-}
-
-int DNS::PruneCache()
-{
- int n = 0;
- dnscache* newcache = new dnscache();
- for (dnscache::iterator i = this->cache->begin(); i != this->cache->end(); i++)
- /* Dont include expired items (theres no point) */
- if (i->second.CalcTTLRemaining())
- newcache->insert(*i);
- else
- n++;
-
- delete this->cache;
- this->cache = newcache;
- return n;
-}
-
-void DNS::Rehash()
-{
- if (this->GetFd() > -1)
- {
- ServerInstance->SE->DelFd(this);
- ServerInstance->SE->Shutdown(this, 2);
- ServerInstance->SE->Close(this);
- this->SetFd(-1);
-
- /* Rehash the cache */
- this->PruneCache();
- }
- else
- {
- /* Create initial dns cache */
- this->cache = new dnscache();
- }
-
- irc::sockets::aptosa(ServerInstance->Config->DNSServer, DNS::QUERY_PORT, myserver);
-
- /* Initialize mastersocket */
- int s = socket(myserver.sa.sa_family, SOCK_DGRAM, 0);
- this->SetFd(s);
-
- /* Have we got a socket and is it nonblocking? */
- if (this->GetFd() != -1)
- {
- ServerInstance->SE->SetReuse(s);
- ServerInstance->SE->NonBlocking(s);
- irc::sockets::sockaddrs bindto;
- memset(&bindto, 0, sizeof(bindto));
- bindto.sa.sa_family = myserver.sa.sa_family;
- if (ServerInstance->SE->Bind(this->GetFd(), bindto) < 0)
- {
- /* Failed to bind */
- ServerInstance->Logs->Log("RESOLVER",SPARSE,"Error binding dns socket - hostnames will NOT resolve");
- ServerInstance->SE->Shutdown(this, 2);
- ServerInstance->SE->Close(this);
- this->SetFd(-1);
- }
- else if (!ServerInstance->SE->AddFd(this, FD_WANT_POLL_READ | FD_WANT_NO_WRITE))
- {
- ServerInstance->Logs->Log("RESOLVER",SPARSE,"Internal error starting DNS - hostnames will NOT resolve.");
- ServerInstance->SE->Shutdown(this, 2);
- ServerInstance->SE->Close(this);
- this->SetFd(-1);
- }
- }
- else
- {
- ServerInstance->Logs->Log("RESOLVER",SPARSE,"Error creating DNS socket - hostnames will NOT resolve");
- }
-}
-
-/** Initialise the DNS UDP socket so that we can send requests */
-DNS::DNS()
-{
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::DNS");
- /* Clear the Resolver class table */
- memset(Classes,0,sizeof(Classes));
-
- /* Clear the requests class table */
- memset(requests,0,sizeof(requests));
-
- /* DNS::Rehash() sets this to a valid ptr
- */
- this->cache = NULL;
-
- /* Again, DNS::Rehash() sets this to a
- * valid value
- */
- this->SetFd(-1);
-
- /* Actually read the settings
- */
- this->Rehash();
-
- this->PruneTimer = new CacheTimer(this);
-
- ServerInstance->Timers->AddTimer(this->PruneTimer);
-}
-
-/** Build a payload to be placed after the header, based upon input data, a resource type, a class and a pointer to a buffer */
-int DNS::MakePayload(const char * const name, const QueryType rr, const unsigned short rr_class, unsigned char * const payload)
-{
- short payloadpos = 0;
- const char* tempchr, *tempchr2 = name;
- unsigned short length;
-
- /* split name up into labels, create query */
- while ((tempchr = strchr(tempchr2,'.')) != NULL)
- {
- length = tempchr - tempchr2;
- if (payloadpos + length + 1 > 507)
- return -1;
- payload[payloadpos++] = length;
- memcpy(&payload[payloadpos],tempchr2,length);
- payloadpos += length;
- tempchr2 = &tempchr[1];
- }
- length = strlen(tempchr2);
- if (length)
- {
- if (payloadpos + length + 2 > 507)
- return -1;
- payload[payloadpos++] = length;
- memcpy(&payload[payloadpos],tempchr2,length);
- payloadpos += length;
- payload[payloadpos++] = 0;
- }
- if (payloadpos > 508)
- return -1;
- length = htons(rr);
- memcpy(&payload[payloadpos],&length,2);
- length = htons(rr_class);
- memcpy(&payload[payloadpos + 2],&length,2);
- return payloadpos + 4;
-}
-
-/** Start lookup of an hostname to an IP address */
-int DNS::GetIP(const char *name)
-{
- DNSHeader h;
- int id;
- int length;
-
- if ((length = this->MakePayload(name, DNS_QUERY_A, 1, (unsigned char*)&h.payload)) == -1)
- return -1;
-
- DNSRequest* req = this->AddQuery(&h, id, name);
-
- if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_A) == -1))
- return -1;
-
- return id;
-}
-
-/** Start lookup of an hostname to an IPv6 address */
-int DNS::GetIP6(const char *name)
-{
- DNSHeader h;
- int id;
- int length;
-
- if ((length = this->MakePayload(name, DNS_QUERY_AAAA, 1, (unsigned char*)&h.payload)) == -1)
- return -1;
-
- DNSRequest* req = this->AddQuery(&h, id, name);
-
- if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_AAAA) == -1))
- return -1;
-
- return id;
-}
-
-/** Start lookup of a cname to another name */
-int DNS::GetCName(const char *alias)
-{
- DNSHeader h;
- int id;
- int length;
-
- if ((length = this->MakePayload(alias, DNS_QUERY_CNAME, 1, (unsigned char*)&h.payload)) == -1)
- return -1;
-
- DNSRequest* req = this->AddQuery(&h, id, alias);
-
- if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_CNAME) == -1))
- return -1;
-
- return id;
-}
-
-/** Start lookup of an IP address to a hostname */
-int DNS::GetNameForce(const char *ip, ForceProtocol fp)
-{
- char query[128];
- DNSHeader h;
- int id;
- int length;
-
- if (fp == PROTOCOL_IPV6)
- {
- in6_addr i;
- if (inet_pton(AF_INET6, ip, &i) > 0)
- {
- DNS::MakeIP6Int(query, &i);
- }
- else
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::GetNameForce IPv6 bad format for '%s'", ip);
- /* Invalid IP address */
- return -1;
- }
- }
- else
- {
- in_addr i;
- if (inet_aton(ip, &i))
- {
- unsigned char* c = (unsigned char*)&i.s_addr;
- sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
- }
- else
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::GetNameForce IPv4 bad format for '%s'", ip);
- /* Invalid IP address */
- return -1;
- }
- }
-
- length = this->MakePayload(query, DNS_QUERY_PTR, 1, (unsigned char*)&h.payload);
- if (length == -1)
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::GetNameForce can't query '%s' using '%s' because it's too long", ip, query);
- return -1;
- }
-
- DNSRequest* req = this->AddQuery(&h, id, ip);
-
- if (!req)
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::GetNameForce can't add query (resolver down?)");
- return -1;
- }
-
- if (req->SendRequests(&h, length, DNS_QUERY_PTR) == -1)
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS::GetNameForce can't send (firewall?)");
- return -1;
- }
-
- return id;
-}
-
-/** Build an ipv6 reverse domain from an in6_addr
- */
-void DNS::MakeIP6Int(char* query, const in6_addr *ip)
-{
- const char* hex = "0123456789abcdef";
- for (int index = 31; index >= 0; index--) /* for() loop steps twice per byte */
- {
- if (index % 2)
- /* low nibble */
- *query++ = hex[ip->s6_addr[index / 2] & 0x0F];
- else
- /* high nibble */
- *query++ = hex[(ip->s6_addr[index / 2] & 0xF0) >> 4];
- *query++ = '.'; /* Seperator */
- }
- strcpy(query,"ip6.arpa"); /* Suffix the string */
-}
-
-/** Return the next id which is ready, and the result attached to it */
-DNSResult DNS::GetResult()
-{
- /* Fetch dns query response and decide where it belongs */
- DNSHeader header;
- DNSRequest *req;
- unsigned char buffer[sizeof(DNSHeader)];
- irc::sockets::sockaddrs from;
- memset(&from, 0, sizeof(from));
- socklen_t x = sizeof(from);
-
- int length = ServerInstance->SE->RecvFrom(this, (char*)buffer, sizeof(DNSHeader), 0, &from.sa, &x);
-
- /* Did we get the whole header? */
- if (length < 12)
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"GetResult didn't get a full packet (len=%d)", length);
- /* Nope - something screwed up. */
- return DNSResult(-1,"",0,"");
- }
-
- /* Check wether the reply came from a different DNS
- * server to the one we sent it to, or the source-port
- * is not 53.
- * A user could in theory still spoof dns packets anyway
- * but this is less trivial than just sending garbage
- * to the server, which is possible without this check.
- *
- * -- Thanks jilles for pointing this one out.
- */
- if (from != myserver)
- {
- std::string server1 = from.str();
- std::string server2 = myserver.str();
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Got a result from the wrong server! Bad NAT or DNS forging attempt? '%s' != '%s'",
- server1.c_str(), server2.c_str());
- return DNSResult(-1,"",0,"");
- }
-
- /* Put the read header info into a header class */
- DNS::FillHeader(&header,buffer,length - 12);
-
- /* Get the id of this request.
- * Its a 16 bit value stored in two char's,
- * so we use logic shifts to create the value.
- */
- unsigned long this_id = header.id[1] + (header.id[0] << 8);
-
- /* Do we have a pending request matching this id? */
- if (!requests[this_id])
- {
- /* Somehow we got a DNS response for a request we never made... */
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Hmm, got a result that we didn't ask for (id=%lx). Ignoring.", this_id);
- return DNSResult(-1,"",0,"");
- }
- else
- {
- /* Remove the query from the list of pending queries */
- req = requests[this_id];
- requests[this_id] = NULL;
- }
-
- /* Inform the DNSRequest class that it has a result to be read.
- * When its finished it will return a DNSInfo which is a pair of
- * unsigned char* resource record data, and an error message.
- */
- DNSInfo data = req->ResultIsReady(header, length);
- std::string resultstr;
-
- /* Check if we got a result, if we didnt, its an error */
- if (data.first == NULL)
- {
- /* An error.
- * Mask the ID with the value of ERROR_MASK, so that
- * the dns_deal_with_classes() function knows that its
- * an error response and needs to be treated uniquely.
- * Put the error message in the second field.
- */
- std::string ro = req->orig;
- delete req;
- return DNSResult(this_id | ERROR_MASK, data.second, 0, ro);
- }
- else
- {
- unsigned long ttl = req->ttl;
- char formatted[128];
-
- /* Forward lookups come back as binary data. We must format them into ascii */
- switch (req->type)
- {
- case DNS_QUERY_A:
- snprintf(formatted,16,"%u.%u.%u.%u",data.first[0],data.first[1],data.first[2],data.first[3]);
- resultstr = formatted;
- break;
-
- case DNS_QUERY_AAAA:
- {
- if (!inet_ntop(AF_INET6, data.first, formatted, sizeof(formatted)))
- {
- std::string ro = req->orig;
- delete req;
- return DNSResult(this_id | ERROR_MASK, "inet_ntop() failed", 0, ro);
- }
-
- resultstr = formatted;
-
- /* Special case. Sending ::1 around between servers
- * and to clients is dangerous, because the : on the
- * start makes the client or server interpret the IP
- * as the last parameter on the line with a value ":1".
- */
- if (*formatted == ':')
- resultstr.insert(0, "0");
- }
- break;
-
- case DNS_QUERY_CNAME:
- /* Identical handling to PTR */
-
- case DNS_QUERY_PTR:
- {
- /* Reverse lookups just come back as char* */
- resultstr = std::string((const char*)data.first);
- if (resultstr.find_first_not_of("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-") != std::string::npos)
- {
- std::string ro = req->orig;
- delete req;
- return DNSResult(this_id | ERROR_MASK, "Invalid char(s) in reply", 0, ro);
- }
- }
- break;
-
- default:
- break;
- }
-
- /* Build the reply with the id and hostname/ip in it */
- std::string ro = req->orig;
- DNSResult result = DNSResult(this_id,resultstr,ttl,ro,req->type);
- delete req;
- return result;
- }
-}
-
-/** A result is ready, process it */
-DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, unsigned length)
-{
- unsigned i = 0, o;
- int q = 0;
- int curanswer;
- ResourceRecord rr;
- unsigned short ptr;
-
- /* This is just to keep _FORTIFY_SOURCE happy */
- rr.type = DNS_QUERY_NONE;
- rr.rdlength = 0;
- rr.ttl = 1; /* GCC is a whiney bastard -- see the XXX below. */
- rr.rr_class = 0; /* Same for VC++ */
-
- if (!(header.flags1 & FLAGS_MASK_QR))
- return std::make_pair((unsigned char*)NULL,"Not a query result");
-
- if (header.flags1 & FLAGS_MASK_OPCODE)
- return std::make_pair((unsigned char*)NULL,"Unexpected value in DNS reply packet");
-
- if (header.flags2 & FLAGS_MASK_RCODE)
- return std::make_pair((unsigned char*)NULL,"Domain name not found");
-
- if (header.ancount < 1)
- return std::make_pair((unsigned char*)NULL,"No resource records returned");
-
- /* Subtract the length of the header from the length of the packet */
- length -= 12;
-
- while ((unsigned int)q < header.qdcount && i < length)
- {
- if (header.payload[i] > 63)
- {
- i += 6;
- q++;
- }
- else
- {
- if (header.payload[i] == 0)
- {
- q++;
- i += 5;
- }
- else i += header.payload[i] + 1;
- }
- }
- curanswer = 0;
- while ((unsigned)curanswer < header.ancount)
- {
- q = 0;
- while (q == 0 && i < length)
- {
- if (header.payload[i] > 63)
- {
- i += 2;
- q = 1;
- }
- else
- {
- if (header.payload[i] == 0)
- {
- i++;
- q = 1;
- }
- else i += header.payload[i] + 1; /* skip length and label */
- }
- }
- if (static_cast<int>(length - i) < 10)
- return std::make_pair((unsigned char*)NULL,"Incorrectly sized DNS reply");
-
- /* XXX: We actually initialise 'rr' here including its ttl field */
- DNS::FillResourceRecord(&rr,&header.payload[i]);
-
- i += 10;
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Resolver: rr.type is %d and this.type is %d rr.class %d this.class %d", rr.type, this->type, rr.rr_class, this->rr_class);
- if (rr.type != this->type)
- {
- curanswer++;
- i += rr.rdlength;
- continue;
- }
- if (rr.rr_class != this->rr_class)
- {
- curanswer++;
- i += rr.rdlength;
- continue;
- }
- break;
- }
- if ((unsigned int)curanswer == header.ancount)
- return std::make_pair((unsigned char*)NULL,"No A, AAAA or PTR type answers (" + ConvToStr(header.ancount) + " answers)");
-
- if (i + rr.rdlength > (unsigned int)length)
- return std::make_pair((unsigned char*)NULL,"Resource record larger than stated");
-
- if (rr.rdlength > 1023)
- return std::make_pair((unsigned char*)NULL,"Resource record too large");
-
- this->ttl = rr.ttl;
-
- switch (rr.type)
- {
- /*
- * CNAME and PTR are compressed. We need to decompress them.
- */
- case DNS_QUERY_CNAME:
- case DNS_QUERY_PTR:
- {
- unsigned short lowest_pos = length;
- o = 0;
- q = 0;
- while (q == 0 && i < length && o + 256 < 1023)
- {
- /* DN label found (byte over 63) */
- if (header.payload[i] > 63)
- {
- memcpy(&ptr,&header.payload[i],2);
-
- i = ntohs(ptr);
-
- /* check that highest two bits are set. if not, we've been had */
- if ((i & DN_COMP_BITMASK) != DN_COMP_BITMASK)
- return std::make_pair((unsigned char *) NULL, "DN label decompression header is bogus");
-
- /* mask away the two highest bits. */
- i &= ~DN_COMP_BITMASK;
-
- /* and decrease length by 12 bytes. */
- i -= 12;
-
- if (i >= lowest_pos)
- return std::make_pair((unsigned char *) NULL, "Invalid decompression pointer");
- lowest_pos = i;
- }
- else
- {
- if (header.payload[i] == 0)
- {
- q = 1;
- }
- else
- {
- res[o] = 0;
- if (o != 0)
- res[o++] = '.';
-
- if (o + header.payload[i] > sizeof(DNSHeader))
- return std::make_pair((unsigned char *) NULL, "DN label decompression is impossible -- malformed/hostile packet?");
-
- memcpy(&res[o], &header.payload[i + 1], header.payload[i]);
- o += header.payload[i];
- i += header.payload[i] + 1;
- }
- }
- }
- res[o] = 0;
- }
- break;
- case DNS_QUERY_AAAA:
- if (rr.rdlength != sizeof(struct in6_addr))
- return std::make_pair((unsigned char *) NULL, "rr.rdlength is larger than 16 bytes for an ipv6 entry -- malformed/hostile packet?");
-
- memcpy(res,&header.payload[i],rr.rdlength);
- res[rr.rdlength] = 0;
- break;
- case DNS_QUERY_A:
- if (rr.rdlength != sizeof(struct in_addr))
- return std::make_pair((unsigned char *) NULL, "rr.rdlength is larger than 4 bytes for an ipv4 entry -- malformed/hostile packet?");
-
- memcpy(res,&header.payload[i],rr.rdlength);
- res[rr.rdlength] = 0;
- break;
- default:
- return std::make_pair((unsigned char *) NULL, "don't know how to handle undefined type (" + ConvToStr(rr.type) + ") -- rejecting");
- break;
- }
- return std::make_pair(res,"No error");
-}
-
-/** Close the master socket */
-DNS::~DNS()
-{
- ServerInstance->SE->Shutdown(this, 2);
- ServerInstance->SE->Close(this);
- ServerInstance->Timers->DelTimer(this->PruneTimer);
- if (cache)
- delete cache;
-}
-
-CachedQuery* DNS::GetCache(const std::string &source)
-{
- dnscache::iterator x = cache->find(source.c_str());
- if (x != cache->end())
- return &(x->second);
- else
- return NULL;
-}
-
-void DNS::DelCache(const std::string &source)
-{
- cache->erase(source.c_str());
-}
-
-void Resolver::TriggerCachedResult()
-{
- if (CQ)
- OnLookupComplete(CQ->data, time_left, true);
-}
-
-/** High level abstraction of dns used by application at large */
-Resolver::Resolver(const std::string &source, QueryType qt, bool &cached, Module* creator) : Creator(creator), input(source), querytype(qt)
-{
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Resolver::Resolver");
- cached = false;
-
- CQ = ServerInstance->Res->GetCache(source);
- if (CQ)
- {
- time_left = CQ->CalcTTLRemaining();
- if (!time_left)
- {
- ServerInstance->Res->DelCache(source);
- }
- else if (CQ->type == qt)
- {
- cached = true;
- return;
- }
- CQ = NULL;
- }
-
- switch (querytype)
- {
- case DNS_QUERY_A:
- this->myid = ServerInstance->Res->GetIP(source.c_str());
- break;
-
- case DNS_QUERY_PTR4:
- querytype = DNS_QUERY_PTR;
- this->myid = ServerInstance->Res->GetNameForce(source.c_str(), PROTOCOL_IPV4);
- break;
-
- case DNS_QUERY_PTR6:
- querytype = DNS_QUERY_PTR;
- this->myid = ServerInstance->Res->GetNameForce(source.c_str(), PROTOCOL_IPV6);
- break;
-
- case DNS_QUERY_AAAA:
- this->myid = ServerInstance->Res->GetIP6(source.c_str());
- break;
-
- case DNS_QUERY_CNAME:
- this->myid = ServerInstance->Res->GetCName(source.c_str());
- break;
-
- default:
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS request with unknown query type %d", querytype);
- this->myid = -1;
- break;
- }
- if (this->myid == -1)
- {
- throw ModuleException("Resolver: Couldn't get an id to make a request");
- }
- else
- {
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"DNS request id %d", this->myid);
- }
-}
-
-/** Called when an error occurs */
-void Resolver::OnError(ResolverError, const std::string&)
-{
- /* Nothing in here */
-}
-
-/** Destroy a resolver */
-Resolver::~Resolver()
-{
- /* Nothing here (yet) either */
-}
-
-/** Get the request id associated with this class */
-int Resolver::GetId()
-{
- return this->myid;
-}
-
-Module* Resolver::GetCreator()
-{
- return this->Creator;
-}
-
-/** Process a socket read event */
-void DNS::HandleEvent(EventType, int)
-{
- /* Fetch the id and result of the next available packet */
- DNSResult res(0,"",0,"");
- res.id = 0;
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Handle DNS event");
-
- res = this->GetResult();
-
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"Result id %d", res.id);
-
- /* Is there a usable request id? */
- if (res.id != -1)
- {
- /* Its an error reply */
- if (res.id & ERROR_MASK)
- {
- /* Mask off the error bit */
- res.id -= ERROR_MASK;
- /* Marshall the error to the correct class */
- if (Classes[res.id])
- {
- if (ServerInstance && ServerInstance->stats)
- ServerInstance->stats->statsDnsBad++;
- Classes[res.id]->OnError(RESOLVER_NXDOMAIN, res.result);
- delete Classes[res.id];
- Classes[res.id] = NULL;
- }
- return;
- }
- else
- {
- /* It is a non-error result, marshall the result to the correct class */
- if (Classes[res.id])
- {
- if (ServerInstance && ServerInstance->stats)
- ServerInstance->stats->statsDnsGood++;
-
- if (!this->GetCache(res.original.c_str()))
- {
- if (cache->size() >= MAX_CACHE_SIZE)
- cache->clear();
- this->cache->insert(std::make_pair(res.original.c_str(), CachedQuery(res.result, res.type, res.ttl)));
- }
-
- Classes[res.id]->OnLookupComplete(res.result, res.ttl, false);
- delete Classes[res.id];
- Classes[res.id] = NULL;
- }
- }
-
- if (ServerInstance && ServerInstance->stats)
- ServerInstance->stats->statsDns++;
- }
-}
-
-/** Add a derived Resolver to the working set */
-bool DNS::AddResolverClass(Resolver* r)
-{
- ServerInstance->Logs->Log("RESOLVER",DEBUG,"AddResolverClass 0x%08lx", (unsigned long)r);
- /* Check the pointers validity and the id's validity */
- if ((r) && (r->GetId() > -1))
- {
- /* Check the slot isnt already occupied -
- * This should NEVER happen unless we have
- * a severely broken DNS server somewhere
- */
- if (!Classes[r->GetId()])
- {
- /* Set up the pointer to the class */
- Classes[r->GetId()] = r;
- return true;
- }
- }
-
- /* Pointer or id not valid, or duplicate id.
- * Free the item and return
- */
- delete r;
- return false;
-}
-
-void DNS::CleanResolvers(Module* module)
-{
- for (int i = 0; i < MAX_REQUEST_ID; i++)
- {
- if (Classes[i])
- {
- if (Classes[i]->GetCreator() == module)
- {
- Classes[i]->OnError(RESOLVER_FORCEUNLOAD, "Parent module is unloading");
- delete Classes[i];
- Classes[i] = NULL;
- }
- }
- }
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 16:12:59 +0000