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upgrade 'tres' so it can now function as your resolver, plus adjust to new simplesocket

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This commit is contained in:
bert hubert 2018-10-16 11:20:10 +02:00
parent 642a5a3522
commit 1677111b2d
3 changed files with 133 additions and 28 deletions
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13
tdns/Makefile
View File

@ -1,4 +1,4 @@
CXXFLAGS:=-std=gnu++14 -Wall -O2 -MMD -MP -ggdb -Iext/simplesocket -Iext/catch -pthread
CXXFLAGS:=-std=gnu++14 -Wall -O2 -MMD -MP -ggdb -Iext/simplesocket -Iext/simplesocket/ext/fmt-5.2.1/include -Iext/catch -pthread
CFLAGS:= -Wall -O2 -MMD -MP -ggdb
PROGRAMS = tdns tdig tres tdns-c-test
@ -14,19 +14,20 @@ check: testrunner tdns tdig
-include *.d
tdns: tdns.o record-types.o dns-storage.o dnsmessages.o contents.o ext/simplesocket/comboaddress.o ext/simplesocket/sclasses.o ext/simplesocket/swrappers.o tdnssec.o
SIMPLESOCKET = ext/simplesocket/comboaddress.o ext/simplesocket/sclasses.o ext/simplesocket/swrappers.o ext/simplesocket/ext/fmt-5.2.1/src/format.o
tdns: tdns.o record-types.o dns-storage.o dnsmessages.o contents.o tdnssec.o $(SIMPLESOCKET)
g++ -std=gnu++14 $^ -o $@ -pthread
tdig: tdig.o record-types.o dns-storage.o dnsmessages.o ext/simplesocket/comboaddress.o ext/simplesocket/sclasses.o ext/simplesocket/swrappers.o
tdig: tdig.o record-types.o dns-storage.o dnsmessages.o $(SIMPLESOCKET)
g++ -std=gnu++14 $^ -o $@ -pthread
tres: tres.o record-types.o dns-storage.o dnsmessages.o ext/simplesocket/comboaddress.o ext/simplesocket/sclasses.o ext/simplesocket/swrappers.o
tres: tres.o record-types.o dns-storage.o dnsmessages.o $(SIMPLESOCKET)
g++ -std=gnu++14 $^ -o $@ -pthread
tdns-c-test: tdns-c-test.o tdns-c.o record-types.o dns-storage.o dnsmessages.o ext/simplesocket/comboaddress.o ext/simplesocket/sclasses.o ext/simplesocket/swrappers.o
tdns-c-test: tdns-c-test.o tdns-c.o record-types.o dns-storage.o dnsmessages.o $(SIMPLESOCKET)
g++ -std=gnu++14 $^ -o $@
testrunner: tests.o record-types.o dns-storage.o dnsmessages.o
g++ -std=gnu++14 $^ -o $@

2
tdns/ext/simplesocket

@ -1 +1 @@
Subproject commit dbadaf003470898fc1471c1621ef3c9e824969d6
Subproject commit 2b02339cddcfa038626b85b87340065845b932ef

146
tdns/tres.cc
View File

@ -6,6 +6,7 @@
#include <signal.h>
#include <random>
#include "record-types.hh"
#include <thread>
/*!
@file
@ -52,7 +53,7 @@ DNSMessageReader getResponse(const ComboAddress& server, const DNSName& dn, cons
bool doEDNS=true, doTCP=false;
for(int tries = 0; tries < 4 ; ++tries) {
if(++g_numqueries > 30) // there is the possibility our algorithm will loop
if(++g_numqueries > 300) // there is the possibility our algorithm will loop
throw TooManyQueriesException(); // and send out thousands of queries, so let's not
DNSMessageWriter dmw(dn, dt);
@ -133,6 +134,22 @@ struct NxdomainException{};
//! Or if your type does not exist
struct NodataException{};
struct ResolveRR
{
DNSName name;
uint32_t ttl;
std::unique_ptr<RRGen> rr;
};
struct ResolveResult
{
vector<ResolveRR> res;
vector<ResolveRR> intermediate;
void clear()
{
res.clear();
intermediate.clear();
}
};
/** This attempts to look up the name dn with type dt. The depth parameter is for
trace output.
@ -141,17 +158,15 @@ struct NodataException{};
root-servers.
*/
vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, int depth=0, const DNSName& auth={}, const multimap<DNSName, ComboAddress>& mservers=g_root)
ResolveResult resolveAt(const DNSName& dn, const DNSType& dt, int depth=0, const DNSName& auth={}, const multimap<DNSName, ComboAddress>& mservers=g_root)
{
std::string prefix(depth, ' ');
prefix += dn.toString() + "|"+toString(dt)+" ";
vector<std::unique_ptr<RRGen>> ret;
// it is good form to sort the servers in order of response time
// for tres, this is not done, but we do randomize
cout << prefix << "Starting query at authority = "<<auth<< ", have "<<mservers.size() << " addresses to try"<<endl;
// it is good form to sort the servers in order of response time
// for tres, this is not done (since we have no memory), but we do randomize:
vector<pair<DNSName, ComboAddress> > servers;
for(auto& sp : mservers)
servers.push_back(sp);
@ -160,6 +175,7 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
std::mt19937 g(rd());
std::shuffle(servers.begin(), servers.end(), g);
ResolveResult ret;
for(auto& sp : servers) {
ret.clear();
ComboAddress server=sp.second;
@ -209,10 +225,12 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
if(dmr.dh.aa==1) {
if(dn == rrdn && dt == rrdt) {
cout << prefix<<"We got an answer to our question!"<<endl;
ret.push_back(std::move(rr));
ret.res.push_back({dn, ttl, std::move(rr)});
}
if(dn == rrdn && rrdt == DNSType::CNAME) {
DNSName target = dynamic_cast<CNAMEGen*>(rr.get())->d_name;
ret.intermediate.push_back({dn, ttl, std::move(rr)}); // rr is DEAD now!
cout << prefix<<"We got a CNAME to " << target <<", chasing"<<endl;
if(target.isPartOf(auth)) { // this points to something we consider this server auth for
@ -221,7 +239,7 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
while(dmr.getRR(rrsection, rrdn, rrdt, ttl, rr)) {
if(rrsection==DNSSection::Answer && rrdn == target && rrdt == dt) {
hadMatch=true;
ret.push_back(std::move(rr));
ret.res.push_back({dn, ttl, std::move(rr)});
}
}
if(hadMatch) { // if it worked, great, otherwise actual chase
@ -232,7 +250,11 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
cout <<prefix<<"in-message chase not successful, will do new query for "<<target<<endl;
}
return resolveAt(target, dt, depth + 1);
auto chaseres=resolveAt(target, dt, depth + 1);
ret.res = std::move(chaseres.res);
for(auto& rr : chaseres.intermediate) // add up their intermediates
ret.intermediate.push_back(std::move(rr));
return ret;
}
}
else {
@ -255,9 +277,9 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
}
}
}
if(!ret.empty()) {
if(!ret.res.empty()) {
// the answer is in!
cout << prefix<<"Done, returning "<<ret.size()<<" results\n";
cout << prefix<<"Done, returning "<<ret.res.size()<<" results, "<<ret.intermediate.size()<<" intermediate\n";
return ret;
}
else if(dmr.dh.aa) {
@ -273,7 +295,7 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
cout << p.first <<"="<<p.second.toString()<<" ";
cout <<endl;
auto res2=resolveAt(dn, dt, depth+1, newAuth, addresses);
if(!res2.empty())
if(!res2.res.empty())
return res2;
cout << prefix<<"The IP addresses we had did not provide a good answer"<<endl;
}
@ -288,9 +310,9 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
for(const DNSType& qtype : {DNSType::A, DNSType::AAAA}) {
try {
auto result = resolveAt(name, qtype, depth+1);
cout << prefix<<"Got "<<result.size()<<" nameserver IPv4 addresses, adding to list"<<endl;
for(const auto& res : result)
newns.insert({name, getIP(res)});
cout << prefix<<"Got "<<result.res.size()<<" nameserver IPv4 addresses, adding to list"<<endl;
for(const auto& res : result.res)
newns.insert({name, getIP(res.rr)});
}
catch(...)
{
@ -303,7 +325,7 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
// we have a new (set) of addresses to try
auto res2 = resolveAt(dn, dt, depth+1, newAuth, newns);
if(!res2.empty()) // it worked!
if(!res2.res.empty()) // it worked!
return res2;
// it didn't, let's move on to the next server
}
@ -316,11 +338,61 @@ vector<std::unique_ptr<RRGen>> resolveAt(const DNSName& dn, const DNSType& dt, i
return ret;
}
void processQuery(int sock, ComboAddress client, DNSMessageReader dmr)
try
{
g_numqueries = 0;
DNSName dn;
DNSType dt;
dmr.getQuestion(dn, dt);
DNSMessageWriter dmw(dn, dt);
dmw.dh.rd = dmr.dh.rd;
dmw.dh.ra = true;
dmw.dh.qr = true;
dmw.dh.id = dmr.dh.id;
ResolveResult res;
try {
res = resolveAt(dn, dt);
cout<<"Result or query for "<< dn <<"|"<<toString(dt)<<endl;
for(const auto& r : res.intermediate) {
cout<<r.name <<" "<<r.ttl<<" "<<r.rr->getType()<<" " << r.rr->toString()<<endl;
}
for(const auto& r : res.res) {
cout<<r.name <<" "<<r.ttl<<" "<<r.rr->getType()<<" "<<r.rr->toString()<<endl;
}
}
catch(NodataException& nd)
{
SSendto(sock, dmw.serialize(), client);
return;
}
catch(NxdomainException& nx)
{
dmw.dh.rcode = (int)RCode::Nxdomain;
SSendto(sock, dmw.serialize(), client);
return;
}
for(const auto& rr : res.intermediate)
dmw.putRR(DNSSection::Answer, rr.name, rr.ttl, rr.rr);
for(const auto& rr : res.res)
dmw.putRR(DNSSection::Answer, rr.name, rr.ttl, rr.rr);
string resp = dmw.serialize();
SSendto(sock, resp, client);
}
catch(exception& e)
{
cerr << "Thread died: " << e.what() << endl;
}
int main(int argc, char** argv)
try
{
if(argc != 3) {
if(argc != 2 && argc != 3) {
cerr<<"Syntax: tres name type\n";
cerr<<"Syntax: tres ip:port\n";
return(EXIT_FAILURE);
}
signal(SIGPIPE, SIG_IGN); // TCP, so we need this
@ -330,7 +402,7 @@ try
{makeDNSName("k.root-servers.net"), ComboAddress("193.0.14.129", 53)},
};
// retrieve the actual live NSSET from the hints
// retrieve the actual live root NSSET from the hints
for(const auto& h : hints) {
try {
DNSMessageReader dmr = getResponse(h.second, makeDNSName("."), DNSType::NS);
@ -353,13 +425,45 @@ try
cout<<"Retrieved . NSSET from hints, have "<<g_root.size()<<" addresses"<<endl;
if(argc == 2) {
ComboAddress local(argv[1]);
Socket sock(local.sin4.sin_family, SOCK_DGRAM);
SBind(sock, local);
string packet;
ComboAddress client;
for(;;) {
try {
packet = SRecvfrom(sock, 1500, client);
cout<<"Received packet from "<< client.toStringWithPort() << endl;
DNSMessageReader dmr(packet);
if(dmr.dh.qr) {
cout << "Packet from " << client.toStringWithPort()<< " was not a query"<<endl;
continue;
}
std::thread t(processQuery, (int)sock, client, dmr);
t.detach();
}
catch(exception& e) {
cout << "Processing packet from " << client.toStringWithPort() <<": "<<e.what() << endl;
}
}
}
// single shot operation
DNSName dn = makeDNSName(argv[1]);
DNSType dt = makeDNSType(argv[2]);
auto res = resolveAt(dn, dt);
cout<<"Result or query for "<< dn <<"|"<<toString(dt)<<endl;
for(const auto& r : res) {
cout<<r->toString()<<endl;
for(const auto& r : res.intermediate) {
cout<<r.name <<" "<<r.ttl<<" "<<r.rr->getType()<<" " << r.rr->toString()<<endl;
}
for(const auto& r : res.res) {
cout<<r.name <<" "<<r.ttl<<" "<<r.rr->getType()<<" "<<r.rr->toString()<<endl;
}
cout<<"Used "<<g_numqueries << " queries"<<endl;
}