mirrors/hello-dns
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it works again

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This commit is contained in:
bert hubert 2018-04-09 20:49:37 +02:00
parent cc894edba6
commit ab91a50402
8 changed files with 118 additions and 51 deletions
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17
tdns/dns-storage.cc
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@ -1,6 +1,23 @@
#include "dns-storage.hh"
using namespace std;
bool dnsname::makeRelative(const dnsname& root)
{
auto us = d_name, them=root.d_name;
while(!them.empty()) {
if(us.empty())
return false;
if(us.back() == them.back()) {
us.pop_back();
them.pop_back();
}
else
return false;
}
d_name = us;
return true;
}
const DNSNode* DNSNode::find(dnsname& name, dnsname& last, bool* passedZonecut) const
{
cout<<"find for '"<<name<<"', last is now '"<<last<<"'"<<endl;

8
tdns/dns-storage.hh
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@ -7,6 +7,7 @@
#include <iostream>
#include <cstdint>
#include <functional>
#include <memory>
#include "nenum.hh"
typedef std::string dnslabel;
@ -44,6 +45,9 @@ struct dnsname
void pop_back() { d_name.pop_back(); }
auto push_front(const dnslabel& dn) { return d_name.push_front(dn); }
auto size() { return d_name.size(); }
bool makeRelative(const dnsname& root);
std::deque<dnslabel> d_name;
};
@ -60,6 +64,10 @@ struct RRGenerator
struct RRSet
{
std::vector<std::unique_ptr<RRGenerator>> contents;
void add(std::unique_ptr<RRGenerator>&& rr)
{
contents.emplace_back(std::move(rr));
}
uint32_t ttl{3600};
};

15
tdns/dns-types.cc
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@ -35,14 +35,15 @@ void SOAGenerator::toMessage(DNSMessageWriter& dmw)
dmw.payload.putUInt32(d_minimum);
}
#if 0
std::string serializeMXRecord(uint16_t prio, const dnsname& mname)
void NameGenerator::toMessage(DNSMessageWriter& dmw)
{
SafeArray<256> sa;
sa.putUInt16(prio);
putName(sa, mname);
return sa.serialize();
putName(dmw.payload, d_name);
}
void MXGenerator::toMessage(DNSMessageWriter& dmw)
{
dmw.payload.putUInt16(d_prio);
putName(dmw.payload, d_name);
}
#endif

29
tdns/dns-types.hh
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@ -37,12 +37,35 @@ struct SOAGenerator : RRGenerator
d_mname(mname), d_rname(rname), d_serial(serial), d_minimum(minimum), d_refresh(refresh), d_retry(retry), d_expire(expire)
{}
template<typename... Targs>
static std::unique_ptr<RRGenerator> make(Targs&&... fargs)
template<typename ... Targs>
static std::unique_ptr<RRGenerator> make(const dnsname& mname, const dnsname& rname, Targs&& ... fargs)
{
return std::move(std::make_unique<SOAGenerator>(std::forward<Targs>(fargs)...));
return std::move(std::make_unique<SOAGenerator>(mname, rname, std::forward<Targs>(fargs)...));
}
void toMessage(DNSMessageWriter& dpw) override;
dnsname d_mname, d_rname;
uint32_t d_serial, d_minimum, d_refresh, d_retry, d_expire;
};
struct NameGenerator : RRGenerator
{
NameGenerator(const dnsname& name) : d_name(name) {}
static std::unique_ptr<RRGenerator> make(const dnsname& mname)
{
return std::move(std::make_unique<NameGenerator>(mname));
}
void toMessage(DNSMessageWriter& dpw) override;
dnsname d_name;
};
struct MXGenerator : RRGenerator
{
MXGenerator(uint16_t prio, const dnsname& name) : d_prio(prio), d_name(name) {}
static std::unique_ptr<RRGenerator> make(uint16_t prio, const dnsname& name)
{
return std::move(std::make_unique<MXGenerator>(prio, name));
}
void toMessage(DNSMessageWriter& dpw) override;
uint16_t d_prio;
dnsname d_name;
};

4
tdns/dnsmessages.cc
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@ -32,9 +32,9 @@ void DNSMessageWriter::putRR(DNSSection section, const dnsname& name, DNSType ty
putName(payload, name);
payload.putUInt16((int)type); payload.putUInt16(1);
payload.putUInt32(ttl);
payload.putUInt16(0); // XXXX
auto pos = payload.putUInt16(0); // placeholder
content->toMessage(*this);
payload.putBlob(content);
payload.putUInt16At(pos, payload.payloadpos-pos-2);
}
catch(...) {
payload.payloadpos = cursize;

1
tdns/dnsmessages.hh
View File

@ -1,3 +1,4 @@
#pragma once
#include "dns.hh"
#include "safearray.hh"
#include "dns-storage.hh"

9
tdns/safearray.hh
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@ -35,11 +35,18 @@ struct SafeArray
payload.at(payloadpos++)=val;
}
void putUInt16(uint16_t val)
uint16_t putUInt16(uint16_t val)
{
val = htons(val);
memcpy(&payload.at(payloadpos+2)-2, &val, 2);
payloadpos+=2;
return payloadpos - 2;
}
void putUInt16At(uint16_t pos, uint16_t val)
{
val = htons(val);
memcpy(&payload.at(pos+2)-2, &val, 2);
}
void putUInt32(uint32_t val)

86
tdns/tdns.cc
View File

@ -18,17 +18,6 @@
using namespace std;
std::string serializeDNSName(const dnsname& dn)
{
std::string ret;
for(const auto & l : dn) {
ret.append(1, l.size());
ret+=l;
}
ret.append(1, (char)0);
return ret;
}
bool processQuestion(const DNSNode& zones, DNSMessageReader& dm, const ComboAddress& local, const ComboAddress& remote, DNSMessageWriter& response)
try
{
@ -67,6 +56,8 @@ try
auto bestzone = fnd->zone;
dnsname searchname(name), lastnode;
bool passedZonecut=false;
int CNAMELoopCount = 0;
loopCNAME:;
auto node = bestzone->find(searchname, lastnode, &passedZonecut);
if(passedZonecut)
response.dh.aa = false;
@ -84,21 +75,32 @@ try
if(iter != node->rrsets.end() && passedZonecut) {
cout<<"Have delegation"<<endl;
const auto& rrset = iter->second;
vector<dnsname> toresolve;
for(const auto& rr : rrset.contents) {
response.putRR(DNSSection::Authority, lastnode+zone, DNSType::NS, rrset.ttl, rr);
toresolve.push_back(dynamic_cast<NameGenerator*>(rr.get())->d_name);
}
dnsname addname{"ns1", "fra"}, wuh;
cout<<"Looking up glue record "<<addname<<endl;
auto addnode = bestzone->find(addname, wuh);
auto iter2 = addnode->rrsets.find(DNSType::A);
if(iter2 != addnode->rrsets.end()) {
cout<<"Lastnode for '"<<addname<<"' glue: "<<wuh<<endl;
const auto& rrset = iter2->second;
for(const auto& rr : rrset.contents) {
response.putRR(DNSSection::Additional, wuh+zone, DNSType::A, rrset.ttl, rr);
for(auto& addname : toresolve ) {
if(!addname.makeRelative(zone)) {
cout<<addname<<" is not within our zone, not doing glue"<<endl;
continue;
}
dnsname wuh;
cout<<"Looking up glue record "<<addname<<" in zone "<<zone<<endl;
auto addnode = bestzone->find(addname, wuh);
if(!addnode || !addname.empty()) {
cout<<"Found nothing, continuing"<<endl;
}
auto iter2 = addnode->rrsets.find(DNSType::A);
if(iter2 != addnode->rrsets.end()) {
cout<<"Lastnode for '"<<addname<<"' glue: "<<wuh<<endl;
const auto& rrset = iter2->second;
for(const auto& rr : rrset.contents) {
response.putRR(DNSSection::Additional, wuh+zone, DNSType::A, rrset.ttl, rr);
}
}
}
// should do additional processing here
}
else {
cout<<"This is an NXDOMAIN situation"<<endl;
@ -128,10 +130,19 @@ try
else if(iter = node->rrsets.find(DNSType::CNAME), iter != node->rrsets.end()) {
cout<<"We do have a CNAME!"<<endl;
const auto& rrset = iter->second;
dnsname target;
for(const auto& rr : rrset.contents) {
response.putRR(DNSSection::Answer, lastnode+zone, DNSType::CNAME, rrset.ttl, rr);
target=dynamic_cast<NameGenerator*>(rr.get())->d_name;
}
cout<<" We should actually follow this, at least within our zone"<<endl;
if(target.makeRelative(zone)) {
cout<<" Should follow CNAME to "<<target<<" within our zone"<<endl;
searchname = target;
if(CNAMELoopCount++ < 10)
goto loopCNAME;
}
else
cout<<" CNAME points to record "<<target<<" in other zone, good luck"<<endl;
}
else {
cout<<"Node exists, qtype doesn't, NOERROR situation, inserting SOA"<<endl;
@ -179,12 +190,11 @@ void udpThread(ComboAddress local, Socket* sock, const DNSNode* zones)
void writeTCPResponse(int sock, const DNSMessageWriter& response)
{
string ser="00"+response.serialize();
cout<<"Should send a message of "<<ser.size()<<" bytes in response"<<endl;
cout<<"Sending a message of "<<ser.size()<<" bytes in response"<<endl;
uint16_t len = htons(ser.length()-2);
ser[0] = *((char*)&len);
ser[1] = *(((char*)&len) + 1);
SWriten(sock, ser);
cout<<"Sent!"<<endl;
}
void tcpClientThread(ComboAddress local, ComboAddress remote, int s, const DNSNode* zones)
@ -210,8 +220,6 @@ void tcpClientThread(ComboAddress local, ComboAddress remote, int s, const DNSNo
return;
}
cout<<"Reading "<<len<<" bytes"<<endl;
message = SRead(sock, len);
DNSMessageReader dm;
memcpy(&dm, message.c_str(), message.size());
@ -305,25 +313,27 @@ void loadZones(DNSNode& zones)
{
auto zone = zones.add({"powerdns", "org"});
zone->zone = new DNSNode(); // XXX ICK
SOAGenerator::make({"ns1", "powerdns", "org"}, {"admin", "powerdns", "org"}, 1);
// zone->zone->rrsets[DNSType::SOA]={{}};
// zone->zone->rrsets[DNSType::MX]={{serializeMXRecord(25, {"server1", "powerdns", "org"})}};
zone->zone->rrsets[DNSType::SOA].add(SOAGenerator::make({"ns1", "powerdns", "org"}, {"admin", "powerdns", "org"}, 1));
zone->zone->rrsets[DNSType::MX].add(MXGenerator::make(25, {"server1", "powerdns", "org"}));
zone->zone->rrsets[DNSType::A]={{serializeARecord("1.2.3.4")}, 300};
zone->zone->rrsets[DNSType::AAAA]={{serializeAAAARecord("::1"), serializeAAAARecord("2001::1"), serializeAAAARecord("2a02:a440:b085:1:beee:7bff:fe89:f0fb")}, 900};
zone->zone->rrsets[DNSType::NS]={{serializeDNSName({"ns1", "powerdns", "org"})}, 300};
zone->zone->rrsets[DNSType::A].add(AGenerator::make("1.2.3.4"));
zone->zone->rrsets[DNSType::AAAA].add(AAAAGenerator::make("::1"));
zone->zone->rrsets[DNSType::AAAA].ttl= 900;
zone->zone->rrsets[DNSType::NS].add(NameGenerator::make({"ns1", "powerdns", "org"}));
zone->zone->add({"www"})->rrsets[DNSType::CNAME]={{serializeDNSName({"server1","powerdns","org"})}};
zone->zone->add({"www"})->rrsets[DNSType::CNAME].add(NameGenerator::make({"server1","powerdns","org"}));
zone->zone->add({"server1"})->rrsets[DNSType::A]={{serializeARecord("213.244.168.210")}};
zone->zone->add({"server1"})->rrsets[DNSType::AAAA]={{serializeAAAARecord("::1")}};
zone->zone->add({"server1"})->rrsets[DNSType::A].add(AGenerator::make("213.244.168.210"));
zone->zone->add({"server1"})->rrsets[DNSType::AAAA].add(AAAAGenerator::make("::1"));
// zone->zone->add({"*"})->rrsets[(dnstype)DNSType::A]={"\x05\x06\x07\x08"};
zone->zone->add({"fra"})->rrsets[DNSType::NS]={{serializeDNSName({"ns1","fra","powerdns","org"})}};
zone->zone->add({"fra"})->rrsets[DNSType::NS].add(NameGenerator::make({"ns1","fra","powerdns","org"}));
zone->zone->add({"fra"})->rrsets[DNSType::NS].add(NameGenerator::make({"ns2","fra","powerdns","org"}));
zone->zone->add({"ns1", "fra"})->rrsets[DNSType::A]={{serializeARecord("12.13.14.15")}, 86400};
zone->zone->add({"NS2", "fra"})->rrsets[DNSType::A]={{serializeARecord("12.13.14.16")}, 86400};
zone->zone->add({"ns1", "fra"})->rrsets[DNSType::A].add(AGenerator::make("12.13.14.15"));
zone->zone->add({"NS2", "fra"})->rrsets[DNSType::A].add(AGenerator::make("12.13.14.16"));
}
int main(int argc, char** argv)