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packethandler.cc
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packethandler.cc
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/*
PowerDNS Versatile Database Driven Nameserver
Copyright (C) 2002-2014 PowerDNS.COM BV
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation
Additionally, the license of this program contains a special
exception which allows to distribute the program in binary form when
it is linked against OpenSSL.
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, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "packetcache.hh"
#include "utility.hh"
#include "base32.hh"
#include <string>
#include <sys/types.h>
#include <boost/algorithm/string.hpp>
#include <boost/foreach.hpp>
#include "dnssecinfra.hh"
#include "dnsseckeeper.hh"
#include "dns.hh"
#include "dnsbackend.hh"
#include "ueberbackend.hh"
#include "dnspacket.hh"
#include "nameserver.hh"
#include "distributor.hh"
#include "logger.hh"
#include "arguments.hh"
#include "packethandler.hh"
#include "statbag.hh"
#include "resolver.hh"
#include "communicator.hh"
#include "dnsproxy.hh"
#include "version.hh"
#include "common_startup.hh"
#if 0
#undef DLOG
#define DLOG(x) x
#endif
AtomicCounter PacketHandler::s_count;
extern string s_programname;
enum root_referral {
NO_ROOT_REFERRAL,
LEAN_ROOT_REFERRAL,
FULL_ROOT_REFERRAL
};
PacketHandler::PacketHandler():B(s_programname)
{
++s_count;
d_doDNAME=::arg().mustDo("experimental-dname-processing");
d_doRecursion= ::arg().mustDo("recursor");
d_logDNSDetails= ::arg().mustDo("log-dns-details");
d_doIPv6AdditionalProcessing = ::arg().mustDo("do-ipv6-additional-processing");
d_sendRootReferral = ::arg().mustDo("send-root-referral")
? ( pdns_iequals(::arg()["send-root-referral"], "lean") ? LEAN_ROOT_REFERRAL : FULL_ROOT_REFERRAL )
: NO_ROOT_REFERRAL;
string fname= ::arg()["lua-prequery-script"];
if(fname.empty())
{
d_pdl = NULL;
}
else
{
d_pdl = new AuthLua(fname);
}
}
DNSBackend *PacketHandler::getBackend()
{
return &B;
}
PacketHandler::~PacketHandler()
{
--s_count;
DLOG(L<<Logger::Error<<"PacketHandler destructor called - "<<s_count<<" left"<<endl);
}
void PacketHandler::addRootReferral(DNSPacket* r)
{
// nobody reads what we output, but it appears to be the magic that shuts some nameservers up
static const char*ips[]={"198.41.0.4", "192.228.79.201", "192.33.4.12", "199.7.91.13", "192.203.230.10", "192.5.5.241", "192.112.36.4", "128.63.2.53",
"192.36.148.17","192.58.128.30", "193.0.14.129", "199.7.83.42", "202.12.27.33"};
static char templ[40];
strncpy(templ,"a.root-servers.net", sizeof(templ) - 1);
// add . NS records
DNSResourceRecord rr;
rr.qtype=QType::NS;
rr.ttl=518400;
rr.d_place=DNSResourceRecord::AUTHORITY;
for(char c='a';c<='m';++c) {
*templ=c;
rr.content=templ;
r->addRecord(rr);
}
if( d_sendRootReferral == LEAN_ROOT_REFERRAL )
return;
// add the additional stuff
rr.ttl=3600000;
rr.qtype=QType::A;
rr.d_place=DNSResourceRecord::ADDITIONAL;
for(char c='a';c<='m';++c) {
*templ=c;
rr.qname=templ;
rr.content=ips[c-'a'];
r->addRecord(rr);
}
}
/** This adds DNSKEY records. Returns true if one was added */
bool PacketHandler::addDNSKEY(DNSPacket *p, DNSPacket *r, const SOAData& sd)
{
DNSResourceRecord rr;
bool haveOne=false;
DNSSECPrivateKey dpk;
DNSSECKeeper::keyset_t keyset = d_dk.getKeys(p->qdomain);
BOOST_FOREACH(DNSSECKeeper::keyset_t::value_type value, keyset) {
rr.qtype=QType::DNSKEY;
rr.ttl=sd.default_ttl;
rr.qname=p->qdomain;
rr.content=value.first.getDNSKEY().getZoneRepresentation();
rr.auth=true;
r->addRecord(rr);
haveOne=true;
}
if(::arg().mustDo("direct-dnskey")) {
B.lookup(QType(QType::DNSKEY), p->qdomain, p, sd.domain_id);
while(B.get(rr)) {
rr.ttl=sd.default_ttl;
r->addRecord(rr);
haveOne=true;
}
}
return haveOne;
}
/** This adds NSEC3PARAM records. Returns true if one was added */
bool PacketHandler::addNSEC3PARAM(DNSPacket *p, DNSPacket *r, const SOAData& sd)
{
DNSResourceRecord rr;
NSEC3PARAMRecordContent ns3prc;
if(d_dk.getNSEC3PARAM(p->qdomain, &ns3prc)) {
rr.qtype=QType::NSEC3PARAM;
rr.ttl=sd.default_ttl;
rr.qname=p->qdomain;
ns3prc.d_flags = 0; // the NSEC3PARAM 'flag' is defined to always be zero in RFC5155.
rr.content=ns3prc.getZoneRepresentation();
rr.auth = true;
r->addRecord(rr);
return true;
}
return false;
}
// This is our chaos class requests handler. Return 1 if content was added, 0 if it wasn't
int PacketHandler::doChaosRequest(DNSPacket *p, DNSPacket *r, string &target)
{
DNSResourceRecord rr;
if(p->qtype.getCode()==QType::TXT) {
if (pdns_iequals(target, "version.pdns") || pdns_iequals(target, "version.bind")) {
// modes: full, powerdns only, anonymous or custom
const static string mode=::arg()["version-string"];
if(mode.empty() || mode=="full")
rr.content=fullVersionString();
else if(mode=="powerdns")
rr.content="Served by PowerDNS - https://www.powerdns.com/";
else if(mode=="anonymous") {
r->setRcode(RCode::ServFail);
return 0;
}
else
rr.content=mode;
}
else if (pdns_iequals(target, "id.server")) {
// modes: disabled, hostname or custom
const static string id=::arg()["server-id"];
if (id == "disabled") {
r->setRcode(RCode::Refused);
return 0;
}
rr.content=id;
}
else {
r->setRcode(RCode::Refused);
return 0;
}
rr.ttl=5;
rr.qname=target;
rr.qtype=QType::TXT;
rr.qclass=QClass::CHAOS;
r->addRecord(rr);
return 1;
}
r->setRcode(RCode::NotImp);
return 0;
}
vector<DNSResourceRecord> PacketHandler::getBestReferralNS(DNSPacket *p, SOAData& sd, const string &target)
{
vector<DNSResourceRecord> ret;
DNSResourceRecord rr;
string subdomain(target);
do {
if(subdomain == sd.qname) // stop at SOA
break;
B.lookup(QType(QType::NS), subdomain, p, sd.domain_id);
while(B.get(rr)) {
ret.push_back(rr); // this used to exclude auth NS records for some reason
}
if(!ret.empty())
return ret;
} while( chopOff( subdomain ) ); // 'www.powerdns.org' -> 'powerdns.org' -> 'org' -> ''
return ret;
}
vector<DNSResourceRecord> PacketHandler::getBestDNAMESynth(DNSPacket *p, SOAData& sd, string &target)
{
vector<DNSResourceRecord> ret;
DNSResourceRecord rr;
string prefix;
string subdomain(target);
do {
DLOG(L<<"Attempting DNAME lookup for "<<subdomain<<", sd.qname="<<sd.qname<<endl);
B.lookup(QType(QType::DNAME), subdomain, p, sd.domain_id);
while(B.get(rr)) {
ret.push_back(rr); // put in the original
rr.qtype = QType::CNAME;
rr.qname = prefix + rr.qname;
rr.content = prefix + rr.content;
target= rr.content;
ret.push_back(rr);
}
if(!ret.empty())
return ret;
string::size_type pos = subdomain.find('.');
if(pos != string::npos)
prefix+= subdomain.substr(0, pos+1);
if(subdomain == sd.qname) // stop at SOA
break;
} while( chopOff( subdomain ) ); // 'www.powerdns.org' -> 'powerdns.org' -> 'org' -> ''
return ret;
}
// Return best matching wildcard or next closer name
bool PacketHandler::getBestWildcard(DNSPacket *p, SOAData& sd, const string &target, string &wildcard, vector<DNSResourceRecord>* ret)
{
ret->clear();
DNSResourceRecord rr;
string subdomain(target);
bool haveSomething=false;
wildcard=subdomain;
while( chopOff( subdomain ) && !haveSomething ) {
if (subdomain.empty()) {
B.lookup(QType(QType::ANY), "*", p, sd.domain_id);
} else {
B.lookup(QType(QType::ANY), "*."+subdomain, p, sd.domain_id);
}
while(B.get(rr)) {
if(rr.qtype == p->qtype || rr.qtype.getCode() == QType::CNAME || (p->qtype.getCode() == QType::ANY && rr.qtype.getCode() != QType::RRSIG))
ret->push_back(rr);
wildcard="*."+subdomain;
haveSomething=true;
}
if ( subdomain == sd.qname || haveSomething ) // stop at SOA or result
break;
B.lookup(QType(QType::ANY), subdomain, p, sd.domain_id);
if (B.get(rr)) {
DLOG(L<<"No wildcard match, ancestor exists"<<endl);
while (B.get(rr)) ;
break;
}
wildcard=subdomain;
}
return haveSomething;
}
/** dangling is declared true if we were unable to resolve everything */
int PacketHandler::doAdditionalProcessingAndDropAA(DNSPacket *p, DNSPacket *r, const SOAData& soadata)
{
DNSResourceRecord rr;
SOAData sd;
sd.db=0;
if(p->qtype.getCode()!=QType::AXFR) { // this packet needs additional processing
vector<DNSResourceRecord *> arrs=r->getAPRecords();
if(arrs.empty())
return 1;
DLOG(L<<Logger::Warning<<"This packet needs additional processing!"<<endl);
vector<DNSResourceRecord> crrs;
for(vector<DNSResourceRecord *>::const_iterator i=arrs.begin(); i!=arrs.end(); ++i)
crrs.push_back(**i);
// we now have a copy, push_back on packet might reallocate!
for(vector<DNSResourceRecord>::const_iterator i=crrs.begin(); i!=crrs.end(); ++i) {
if(r->d.aa && !i->qname.empty() && i->qtype.getCode()==QType::NS && !B.getSOA(i->qname,sd,p)) { // drop AA in case of non-SOA-level NS answer, except for root referral
r->setA(false);
// i->d_place=DNSResourceRecord::AUTHORITY; // XXX FIXME
}
string content = stripDot(i->content);
QType qtypes[2];
qtypes[0]="A"; qtypes[1]="AAAA";
for(int n=0 ; n < d_doIPv6AdditionalProcessing + 1; ++n) {
if (i->qtype.getCode()==QType::SRV) {
vector<string>parts;
stringtok(parts, content);
if (parts.size() >= 3) {
B.lookup(qtypes[n],parts[2],p);
}
else
continue;
}
else {
B.lookup(qtypes[n], content, p);
}
while(B.get(rr)) {
if(rr.domain_id!=i->domain_id && ::arg()["out-of-zone-additional-processing"]=="no") {
DLOG(L<<Logger::Warning<<"Not including out-of-zone additional processing of "<<i->qname<<" ("<<rr.qname<<")"<<endl);
continue; // not adding out-of-zone additional data
}
if(rr.auth && !endsOn(rr.qname, soadata.qname)) // don't sign out of zone data using the main key
rr.auth=false;
rr.d_place=DNSResourceRecord::ADDITIONAL;
r->addRecord(rr);
}
}
}
}
return 1;
}
void PacketHandler::emitNSEC(const std::string& begin, const std::string& end, const std::string& toNSEC, const SOAData& sd, DNSPacket *r, int mode)
{
// cerr<<"We should emit '"<<begin<<"' - ('"<<toNSEC<<"') - '"<<end<<"'"<<endl;
NSECRecordContent nrc;
nrc.d_set.insert(QType::RRSIG);
nrc.d_set.insert(QType::NSEC);
if(pdns_iequals(sd.qname, begin)) {
nrc.d_set.insert(QType::SOA);
nrc.d_set.insert(QType::DNSKEY);
}
DNSResourceRecord rr;
B.lookup(QType(QType::ANY), begin, NULL, sd.domain_id);
while(B.get(rr)) {
if(rr.qtype.getCode() == QType::NS || rr.auth)
nrc.d_set.insert(rr.qtype.getCode());
}
nrc.d_next=end;
rr.qname=begin;
rr.ttl = sd.default_ttl;
rr.qtype=QType::NSEC;
rr.content=nrc.getZoneRepresentation();
rr.d_place = (mode == 5 ) ? DNSResourceRecord::ANSWER: DNSResourceRecord::AUTHORITY;
rr.auth = true;
r->addRecord(rr);
}
void emitNSEC3(DNSBackend& B, const NSEC3PARAMRecordContent& ns3prc, const SOAData& sd, const std::string& unhashed, const std::string& begin, const std::string& end, const std::string& toNSEC3, DNSPacket *r, int mode)
{
// cerr<<"We should emit NSEC3 '"<<toBase32Hex(begin)<<"' - ('"<<toNSEC3<<"') - '"<<toBase32Hex(end)<<"' (unhashed: '"<<unhashed<<"')"<<endl;
NSEC3RecordContent n3rc;
n3rc.d_salt=ns3prc.d_salt;
n3rc.d_flags = ns3prc.d_flags;
n3rc.d_iterations = ns3prc.d_iterations;
n3rc.d_algorithm = 1; // SHA1, fixed in PowerDNS for now
DNSResourceRecord rr;
if(!unhashed.empty()) {
B.lookup(QType(QType::ANY), unhashed, NULL, sd.domain_id);
while(B.get(rr)) {
if(rr.qtype.getCode() && (rr.qtype.getCode() == QType::NS || rr.auth)) // skip empty non-terminals
n3rc.d_set.insert(rr.qtype.getCode());
}
if (pdns_iequals(sd.qname, unhashed)) {
n3rc.d_set.insert(QType::SOA);
n3rc.d_set.insert(QType::NSEC3PARAM);
n3rc.d_set.insert(QType::DNSKEY);
}
}
if (n3rc.d_set.size() && !(n3rc.d_set.size() == 1 && n3rc.d_set.count(QType::NS)))
n3rc.d_set.insert(QType::RRSIG);
n3rc.d_nexthash=end;
rr.qname=dotConcat(toBase32Hex(begin), sd.qname);
rr.ttl = sd.default_ttl;
rr.qtype=QType::NSEC3;
rr.content=n3rc.getZoneRepresentation();
rr.d_place = (mode == 5 ) ? DNSResourceRecord::ANSWER: DNSResourceRecord::AUTHORITY;
rr.auth = true;
r->addRecord(rr);
}
void PacketHandler::emitNSEC3(const NSEC3PARAMRecordContent& ns3prc, const SOAData& sd, const std::string& unhashed, const std::string& begin, const std::string& end, const std::string& toNSEC3, DNSPacket *r, int mode)
{
::emitNSEC3(B, ns3prc, sd, unhashed, begin, end, toNSEC3, r, mode);
}
/*
mode 0 = No Data Responses, QTYPE is not DS
mode 1 = No Data Responses, QTYPE is DS
mode 2 = Wildcard No Data Responses
mode 3 = Wildcard Answer Responses
mode 4 = Name Error Responses
mode 5 = Direct NSEC request
*/
void PacketHandler::addNSECX(DNSPacket *p, DNSPacket *r, const string& target, const string& wildcard, const string& auth, int mode)
{
if(!p->d_dnssecOk && mode != 5)
return;
NSEC3PARAMRecordContent ns3rc;
// cerr<<"Doing NSEC3PARAM lookup for '"<<auth<<"', "<<p->qdomain<<"|"<<p->qtype.getName()<<": ";
bool narrow;
if(d_dk.getNSEC3PARAM(auth, &ns3rc, &narrow)) {
// cerr<<"Present, narrow="<<narrow<<endl;
if (mode != 5) // no direct NSEC3 please
addNSEC3(p, r, target, wildcard, auth, ns3rc, narrow, mode);
}
else {
// cerr<<"Not present"<<endl;
addNSEC(p, r, target, wildcard, auth, mode);
}
}
static void incrementHash(std::string& raw) // I wonder if this is correct, cmouse? ;-)
{
if(raw.empty())
return;
for(string::size_type pos=raw.size(); pos; ) {
--pos;
unsigned char c = (unsigned char)raw[pos];
++c;
raw[pos] = (char) c;
if(c)
break;
}
}
static void decrementHash(std::string& raw) // I wonder if this is correct, cmouse? ;-)
{
if(raw.empty())
return;
for(string::size_type pos=raw.size(); pos; ) {
--pos;
unsigned char c = (unsigned char)raw[pos];
--c;
raw[pos] = (char) c;
if(c != 0xff)
break;
}
}
bool getNSEC3Hashes(bool narrow, DNSBackend* db, int id, const std::string& hashed, bool decrement, string& unhashed, string& before, string& after, int mode)
{
bool ret;
if(narrow) { // nsec3-narrow
ret=true;
before=hashed;
if(decrement) {
decrementHash(before);
unhashed.clear();
}
after=hashed;
incrementHash(after);
}
else {
if (decrement || mode <= 1)
before.clear();
else
before=' ';
ret=db->getBeforeAndAfterNamesAbsolute(id, toBase32Hex(hashed), unhashed, before, after);
before=fromBase32Hex(before);
after=fromBase32Hex(after);
}
// cerr<<"rgetNSEC3Hashes: "<<hashed<<", "<<unhashed<<", "<<before<<", "<<after<<endl;
return ret;
}
void PacketHandler::addNSEC3(DNSPacket *p, DNSPacket *r, const string& target, const string& wildcard, const string& auth, const NSEC3PARAMRecordContent& ns3rc, bool narrow, int mode)
{
DLOG(L<<"addNSEC3() mode="<<mode<<" auth="<<auth<<" target="<<target<<" wildcard="<<wildcard<<endl);
SOAData sd;
sd.db = (DNSBackend*)-1; // force uncached answer
if(!B.getSOA(auth, sd)) {
DLOG(L<<"Could not get SOA for domain");
return;
}
bool doNextcloser = false;
string unhashed, hashed, before, after;
string closest;
DNSResourceRecord rr;
if (mode == 2 || mode == 3 || mode == 4) {
closest=wildcard;
(void) chopOff(closest);
} else
closest=target;
// add matching NSEC3 RR
if (mode != 3) {
unhashed=(mode == 0 || mode == 1 || mode == 5) ? target : closest;
hashed=hashQNameWithSalt(ns3rc.d_iterations, ns3rc.d_salt, unhashed);
DLOG(L<<"1 hash: "<<toBase32Hex(hashed)<<" "<<unhashed<<endl);
if(!B.getDirectNSECx(sd.domain_id, hashed, QType(QType::NSEC3), before, rr))
getNSEC3Hashes(narrow, sd.db, sd.domain_id, hashed, false, unhashed, before, after, mode);
if (((mode == 0 && ns3rc.d_flags) || mode == 1) && (hashed != before)) {
DLOG(L<<"No matching NSEC3, do closest (provable) encloser"<<endl);
bool doBreak = false;
DNSResourceRecord rr;
while( chopOff( closest ) && (closest != sd.qname)) { // stop at SOA
B.lookup(QType(QType::ANY), closest, p, sd.domain_id);
while(B.get(rr))
if (rr.auth)
doBreak = true;
if(doBreak)
break;
}
doNextcloser = true;
unhashed=closest;
hashed=hashQNameWithSalt(ns3rc.d_iterations, ns3rc.d_salt, unhashed);
DLOG(L<<"1 hash: "<<toBase32Hex(hashed)<<" "<<unhashed<<endl);
if(!B.getDirectNSECx(sd.domain_id, hashed, QType(QType::NSEC3), before, rr))
getNSEC3Hashes(narrow, sd.db, sd.domain_id, hashed, false, unhashed, before, after);
}
if (!after.empty()) {
DLOG(L<<"Done calling for matching, hashed: '"<<toBase32Hex(hashed)<<"' before='"<<toBase32Hex(before)<<"', after='"<<toBase32Hex(after)<<"'"<<endl);
emitNSEC3(ns3rc, sd, unhashed, before, after, target, r, mode);
} else if(!before.empty())
r->addRecord(rr);
}
// add covering NSEC3 RR
if ((mode >= 2 && mode <= 4) || doNextcloser) {
string next(target);
do {
unhashed=next;
}
while( chopOff( next ) && !pdns_iequals(next, closest));
hashed=hashQNameWithSalt(ns3rc.d_iterations, ns3rc.d_salt, unhashed);
DLOG(L<<"2 hash: "<<toBase32Hex(hashed)<<" "<<unhashed<<endl);
if(!B.getDirectNSECx(sd.domain_id, hashed, QType(QType::NSEC3), before, rr)) {
getNSEC3Hashes(narrow, sd.db,sd.domain_id, hashed, true, unhashed, before, after);
DLOG(L<<"Done calling for covering, hashed: '"<<toBase32Hex(hashed)<<"' before='"<<toBase32Hex(before)<<"', after='"<<toBase32Hex(after)<<"'"<<endl);
emitNSEC3( ns3rc, sd, unhashed, before, after, target, r, mode);
} else if(!before.empty())
r->addRecord(rr);
}
// wildcard denial
if (mode == 2 || mode == 4) {
unhashed=dotConcat("*", closest);
hashed=hashQNameWithSalt(ns3rc.d_iterations, ns3rc.d_salt, unhashed);
DLOG(L<<"3 hash: "<<toBase32Hex(hashed)<<" "<<unhashed<<endl);
if(!B.getDirectNSECx(sd.domain_id, hashed, QType(QType::NSEC3), before, rr)) {
getNSEC3Hashes(narrow, sd.db, sd.domain_id, hashed, (mode != 2), unhashed, before, after);
DLOG(L<<"Done calling for '*', hashed: '"<<toBase32Hex(hashed)<<"' before='"<<toBase32Hex(before)<<"', after='"<<toBase32Hex(after)<<"'"<<endl);
emitNSEC3( ns3rc, sd, unhashed, before, after, target, r, mode);
} else if(!before.empty())
r->addRecord(rr);
}
}
void PacketHandler::addNSEC(DNSPacket *p, DNSPacket *r, const string& target, const string& wildcard, const string& auth, int mode)
{
DLOG(L<<"addNSEC() mode="<<mode<<" auth="<<auth<<" target="<<target<<" wildcard="<<wildcard<<endl);
SOAData sd;
sd.db=(DNSBackend *)-1; // force uncached answer
if(!B.getSOA(auth, sd)) {
DLOG(L<<"Could not get SOA for domain"<<endl);
return;
}
string before,after;
DNSResourceRecord rr;
rr.auth=false;
if(!B.getDirectNSECx(sd.domain_id, toLower(labelReverse(makeRelative(target, auth))), QType(QType::NSEC), before, rr)) {
sd.db->getBeforeAndAfterNames(sd.domain_id, auth, target, before, after);
emitNSEC(before, after, target, sd, r, mode);
} else if(rr.auth) {
if (mode == 5)
rr.d_place=DNSResourceRecord::ANSWER;
r->addRecord(rr);
}
if (mode == 2 || mode == 4) {
// wildcard NO-DATA or wildcard denial
before.clear();
string closest(wildcard);
if (mode == 4) {
(void) chopOff(closest);
closest=dotConcat("*", closest);
}
rr.auth=false;
if(!B.getDirectNSECx(sd.domain_id, toLower(labelReverse(makeRelative(closest, auth))), QType(QType::NSEC), before, rr)) {
sd.db->getBeforeAndAfterNames(sd.domain_id, auth, closest, before, after);
emitNSEC(before, after, target, sd, r, mode);
} else if(rr.auth)
r->addRecord(rr);
}
return;
}
/* Semantics:
- only one backend owns the SOA of a zone
- only one AXFR per zone at a time - double startTransaction should fail
- backends need to implement transaction semantics
How BindBackend would implement this:
startTransaction makes a file
feedRecord sends everything to that file
commitTransaction moves that file atomically over the regular file, and triggers a reload
rollbackTransaction removes the file
How PostgreSQLBackend would implement this:
startTransaction starts a sql transaction, which also deletes all records
feedRecord is an insert statement
commitTransaction commits the transaction
rollbackTransaction aborts it
How MySQLBackend would implement this:
(good question!)
*/
int PacketHandler::trySuperMaster(DNSPacket *p)
{
if(p->d_tcp)
{
// do it right now if the client is TCP
// rarely happens
return trySuperMasterSynchronous(p);
}
else
{
// queue it if the client is on UDP
Communicator.addTrySuperMasterRequest(p);
return 0;
}
}
int PacketHandler::trySuperMasterSynchronous(DNSPacket *p)
{
Resolver::res_t nsset;
try {
Resolver resolver;
uint32_t theirserial;
resolver.getSoaSerial(p->getRemote(),p->qdomain, &theirserial);
resolver.resolve(p->getRemote(), p->qdomain.c_str(), QType::NS, &nsset);
}
catch(ResolverException &re) {
L<<Logger::Error<<"Error resolving SOA or NS for "<<p->qdomain<<" at: "<< p->getRemote() <<": "<<re.reason<<endl;
return RCode::ServFail;
}
string nameserver, account;
DNSBackend *db;
if(!B.superMasterBackend(p->getRemote(), p->qdomain, nsset, &nameserver, &account, &db)) {
L<<Logger::Error<<"Unable to find backend willing to host "<<p->qdomain<<" for potential supermaster "<<p->getRemote()<<". "<<nsset.size()<<" remote nameservers: "<<endl;
BOOST_FOREACH(class DNSResourceRecord& rr, nsset) {
L<<Logger::Error<<rr.content<<endl;
}
return RCode::Refused;
}
try {
db->createSlaveDomain(p->getRemote(), p->qdomain, nameserver, account);
}
catch(PDNSException& ae) {
L<<Logger::Error<<"Database error trying to create "<<p->qdomain<<" for potential supermaster "<<p->getRemote()<<": "<<ae.reason<<endl;
return RCode::ServFail;
}
L<<Logger::Warning<<"Created new slave zone '"<<p->qdomain<<"' from supermaster "<<p->getRemote()<<endl;
return RCode::NoError;
}
int PacketHandler::processNotify(DNSPacket *p)
{
/* now what?
was this notification from an approved address?
We determine our internal SOA id (via UeberBackend)
We determine the SOA at our (known) master
if master is higher -> do stuff
*/
if(!::arg().mustDo("slave")) {
L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" but slave support is disabled in the configuration"<<endl;
return RCode::NotImp;
}
DNSBackend *db=0;
DomainInfo di;
di.serial = 0;
if(!B.getDomainInfo(p->qdomain, di) || !(db=di.backend)) {
L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" for which we are not authoritative"<<endl;
return trySuperMaster(p);
}
if(::arg().contains("trusted-notification-proxy", p->getRemote())) {
L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from trusted-notification-proxy "<< p->getRemote()<<endl;
if(di.masters.empty()) {
L<<Logger::Error<<"However, "<<p->qdomain<<" does not have any masters defined"<<endl;
return RCode::Refused;
}
}
else if(!db->isMaster(p->qdomain, p->getRemote())) {
L<<Logger::Error<<"Received NOTIFY for "<<p->qdomain<<" from "<<p->getRemote()<<" which is not a master"<<endl;
return RCode::Refused;
}
// ok, we've done our checks
di.backend = 0;
Communicator.addSlaveCheckRequest(di, p->d_remote);
return 0;
}
bool validDNSName(const string &name)
{
string::size_type pos, length=name.length();
char c;
for(pos=0; pos < length; ++pos) {
c=name[pos];
if(!((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
c =='-' || c == '_' || c=='*' || c=='.' || c=='/' || c=='@' || c==' ' || c=='\\' || c==':'))
return false;
}
return true;
}
DNSPacket *PacketHandler::question(DNSPacket *p)
{
DNSPacket *ret;
if(d_pdl)
{
ret=d_pdl->prequery(p);
if(ret)
return ret;
}
if(p->d.rd) {
static unsigned int &rdqueries=*S.getPointer("rd-queries");
rdqueries++;
}
bool shouldRecurse=false;
ret=questionOrRecurse(p, &shouldRecurse);
if(shouldRecurse) {
DP->sendPacket(p);
}
return ret;
}
void PacketHandler::makeNXDomain(DNSPacket* p, DNSPacket* r, const std::string& target, const std::string& wildcard, SOAData& sd)
{
DNSResourceRecord rr;
rr.qname=sd.qname;
rr.qtype=QType::SOA;
rr.content=serializeSOAData(sd);
rr.ttl=min(sd.ttl, sd.default_ttl);
rr.signttl=sd.ttl;
rr.domain_id=sd.domain_id;
rr.d_place=DNSResourceRecord::AUTHORITY;
rr.auth = 1;
rr.scopeMask = sd.scopeMask;
r->addRecord(rr);
if(d_dk.isSecuredZone(sd.qname))
addNSECX(p, r, target, wildcard, sd.qname, 4);
r->setRcode(RCode::NXDomain);
}
void PacketHandler::makeNOError(DNSPacket* p, DNSPacket* r, const std::string& target, const std::string& wildcard, SOAData& sd, int mode)
{
DNSResourceRecord rr;
rr.qname=sd.qname;
rr.qtype=QType::SOA;
rr.content=serializeSOAData(sd);
rr.ttl=sd.ttl;
rr.ttl=min(sd.ttl, sd.default_ttl);
rr.signttl=sd.ttl;
rr.domain_id=sd.domain_id;
rr.d_place=DNSResourceRecord::AUTHORITY;
rr.auth = 1;
r->addRecord(rr);
if(d_dk.isSecuredZone(sd.qname))
addNSECX(p, r, target, wildcard, sd.qname, mode);
S.ringAccount("noerror-queries",p->qdomain+"/"+p->qtype.getName());
}
bool PacketHandler::addDSforNS(DNSPacket* p, DNSPacket* r, SOAData& sd, const string& dsname)
{
//cerr<<"Trying to find a DS for '"<<dsname<<"', domain_id = "<<sd.domain_id<<endl;
B.lookup(QType(QType::DS), dsname, p, sd.domain_id);
DNSResourceRecord rr;
bool gotOne=false;
while(B.get(rr)) {
gotOne=true;
rr.d_place = DNSResourceRecord::AUTHORITY;
r->addRecord(rr);
}
return gotOne;
}
bool PacketHandler::tryReferral(DNSPacket *p, DNSPacket*r, SOAData& sd, const string &target)
{
vector<DNSResourceRecord> rrset = getBestReferralNS(p, sd, target);
if(rrset.empty())
return false;
DLOG(L<<"The best NS is: "<<rrset.begin()->qname<<endl);
BOOST_FOREACH(DNSResourceRecord rr, rrset) {
DLOG(L<<"\tadding '"<<rr.content<<"'"<<endl);
rr.d_place=DNSResourceRecord::AUTHORITY;
r->addRecord(rr);
}
r->setA(false);
if(d_dk.isSecuredZone(sd.qname) && !addDSforNS(p, r, sd, rrset.begin()->qname))
addNSECX(p, r, rrset.begin()->qname, "", sd.qname, 1);
return true;
}
void PacketHandler::completeANYRecords(DNSPacket *p, DNSPacket*r, SOAData& sd, const string &target)
{
if(!p->d_dnssecOk)
return; // Don't send dnssec info to non validating resolvers.
if(!d_dk.isSecuredZone(sd.qname))
return;
addNSECX(p, r, target, "", sd.qname, 5);
if(pdns_iequals(sd.qname, p->qdomain)) {
addDNSKEY(p, r, sd);
addNSEC3PARAM(p, r, sd);
}
}
bool PacketHandler::tryDNAME(DNSPacket *p, DNSPacket*r, SOAData& sd, string &target)
{
if(!d_doDNAME)
return false;
DLOG(L<<Logger::Warning<<"Let's try DNAME.."<<endl);
vector<DNSResourceRecord> rrset = getBestDNAMESynth(p, sd, target);
if(!rrset.empty()) {
BOOST_FOREACH(DNSResourceRecord& rr, rrset) {
rr.d_place = DNSResourceRecord::ANSWER;
r->addRecord(rr);
}
return true;
}
return false;
}
bool PacketHandler::tryWildcard(DNSPacket *p, DNSPacket*r, SOAData& sd, string &target, string &wildcard, bool& retargeted, bool& nodata)
{
retargeted = nodata = false;
string bestmatch;
vector<DNSResourceRecord> rrset;
if(!getBestWildcard(p, sd, target, wildcard, &rrset))
return false;
if(rrset.empty()) {
DLOG(L<<"Wildcard matched something, but not of the correct type"<<endl);
nodata=true;
}
else {
DLOG(L<<"The best wildcard match: "<<rrset.begin()->qname<<endl);
BOOST_FOREACH(DNSResourceRecord rr, rrset) {
rr.wildcardname = rr.qname;
rr.qname=bestmatch=target;
if(rr.qtype.getCode() == QType::CNAME) {
retargeted=true;
target=rr.content;
}
DLOG(L<<"\tadding '"<<rr.content<<"'"<<endl);
rr.d_place=DNSResourceRecord::ANSWER;
r->addRecord(rr);
}
}
if(d_dk.isSecuredZone(sd.qname) && !nodata) {
addNSECX(p, r, bestmatch, wildcard, sd.qname, 3);
}
return true;
}
//! Called by the Distributor to ask a question. Returns 0 in case of an error
DNSPacket *PacketHandler::questionOrRecurse(DNSPacket *p, bool *shouldRecurse)
{
*shouldRecurse=false;
DNSResourceRecord rr;
SOAData sd;
sd.db=0;
string subdomain="";
string soa;
int retargetcount=0;
set<string, CIStringCompare> authSet;
vector<DNSResourceRecord> rrset;
bool weDone=0, weRedirected=0, weHaveUnauth=0;
DNSPacket *r=0;
bool noCache=false;
if(p->d.qr) { // QR bit from dns packet (thanks RA from N)
L<<Logger::Error<<"Received an answer (non-query) packet from "<<p->getRemote()<<", dropping"<<endl;
S.inc("corrupt-packets");
S.ringAccount("remotes-corrupt", p->getRemote());
return 0;
}
if(p->d_havetsig) {
string keyname, secret;
TSIGRecordContent trc;
if(!checkForCorrectTSIG(p, &B, &keyname, &secret, &trc)) {
r=p->replyPacket(); // generate an empty reply packet
if(d_logDNSDetails)
L<<Logger::Error<<"Received a TSIG signed message with a non-validating key"<<endl;
// RFC3007 describes that a non-secure message should be sending Refused for DNS Updates
if (p->d.opcode == Opcode::Update)
r->setRcode(RCode::Refused);
else