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/*
* This file is part of PowerDNS or dnsdist.
* Copyright -- PowerDNS.COM B.V. and its contributors
*
* 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.
*
* In addition, for the avoidance of any doubt, permission is granted to
* link this program with OpenSSL and to (re)distribute the binaries
* produced as the result of such linking.
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#pragma once
#include <time.h>
#include <unordered_map>
#include <boost/variant.hpp>
#include "circular_buffer.hh"
#include "dnsname.hh"
#include "iputils.hh"
#include "lock.hh"
#include "stat_t.hh"
#include "dnsdist-protocols.hh"
struct Rings {
struct Query
{
ComboAddress requestor;
DNSName name;
struct timespec when;
struct dnsheader dh;
uint16_t size;
uint16_t qtype;
// incoming protocol
dnsdist::Protocol protocol;
};
struct Response
{
ComboAddress requestor;
ComboAddress ds; // who handled it
DNSName name;
struct timespec when;
struct dnsheader dh;
unsigned int usec;
unsigned int size;
uint16_t qtype;
// outgoing protocol
dnsdist::Protocol protocol;
};
struct Shard
{
LockGuarded<boost::circular_buffer<Query>> queryRing{boost::circular_buffer<Query>()};
LockGuarded<boost::circular_buffer<Response>> respRing{boost::circular_buffer<Response>()};
};
Rings(size_t capacity=10000, size_t numberOfShards=10, size_t nbLockTries=5, bool keepLockingStats=false): d_blockingQueryInserts(0), d_blockingResponseInserts(0), d_deferredQueryInserts(0), d_deferredResponseInserts(0), d_nbQueryEntries(0), d_nbResponseEntries(0), d_currentShardId(0), d_numberOfShards(numberOfShards), d_nbLockTries(nbLockTries), d_keepLockingStats(keepLockingStats)
{
setCapacity(capacity, numberOfShards);
}
std::unordered_map<int, vector<boost::variant<string,double> > > getTopBandwidth(unsigned int numentries);
size_t numDistinctRequestors();
/* This function should only be called at configuration time before any query or response has been inserted */
void setCapacity(size_t newCapacity, size_t numberOfShards)
{
if (numberOfShards <= 1) {
d_nbLockTries = 0;
}
d_shards.resize(numberOfShards);
d_numberOfShards = numberOfShards;
/* resize all the rings */
for (auto& shard : d_shards) {
shard = std::make_unique<Shard>();
shard->queryRing.lock()->set_capacity(newCapacity / numberOfShards);
shard->respRing.lock()->set_capacity(newCapacity / numberOfShards);
}
/* we just recreated the shards so they are now empty */
d_nbQueryEntries = 0;
d_nbResponseEntries = 0;
}
void setNumberOfLockRetries(size_t retries)
{
if (d_numberOfShards <= 1) {
d_nbLockTries = 0;
} else {
d_nbLockTries = retries;
}
}
size_t getNumberOfShards() const
{
return d_numberOfShards;
}
size_t getNumberOfQueryEntries() const
{
return d_nbQueryEntries;
}
size_t getNumberOfResponseEntries() const
{
return d_nbResponseEntries;
}
void insertQuery(const struct timespec& when, const ComboAddress& requestor, const DNSName& name, uint16_t qtype, uint16_t size, const struct dnsheader& dh, dnsdist::Protocol protocol)
{
for (size_t idx = 0; idx < d_nbLockTries; idx++) {
auto& shard = getOneShard();
auto lock = shard->queryRing.try_lock();
if (lock.owns_lock()) {
insertQueryLocked(*lock, when, requestor, name, qtype, size, dh, protocol);
return;
}
if (d_keepLockingStats) {
++d_deferredQueryInserts;
}
}
/* out of luck, let's just wait */
if (d_keepLockingStats) {
++d_blockingResponseInserts;
}
auto& shard = getOneShard();
auto lock = shard->queryRing.lock();
insertQueryLocked(*lock, when, requestor, name, qtype, size, dh, protocol);
}
void insertResponse(const struct timespec& when, const ComboAddress& requestor, const DNSName& name, uint16_t qtype, unsigned int usec, unsigned int size, const struct dnsheader& dh, const ComboAddress& backend, dnsdist::Protocol protocol)
{
for (size_t idx = 0; idx < d_nbLockTries; idx++) {
auto& shard = getOneShard();
auto lock = shard->respRing.try_lock();
if (lock.owns_lock()) {
insertResponseLocked(*lock, when, requestor, name, qtype, usec, size, dh, backend, protocol);
return;
}
if (d_keepLockingStats) {
++d_deferredResponseInserts;
}
}
/* out of luck, let's just wait */
if (d_keepLockingStats) {
++d_blockingResponseInserts;
}
auto& shard = getOneShard();
auto lock = shard->respRing.lock();
insertResponseLocked(*lock, when, requestor, name, qtype, usec, size, dh, backend, protocol);
}
void clear()
{
for (auto& shard : d_shards) {
shard->queryRing.lock()->clear();
shard->respRing.lock()->clear();
}
d_nbQueryEntries.store(0);
d_nbResponseEntries.store(0);
d_currentShardId.store(0);
d_blockingQueryInserts.store(0);
d_blockingResponseInserts.store(0);
d_deferredQueryInserts.store(0);
d_deferredResponseInserts.store(0);
}
/* load the content of the ring buffer from a file in the format emitted by grepq(),
only useful for debugging purposes */
size_t loadFromFile(const std::string& filepath, const struct timespec& now);
std::vector<std::unique_ptr<Shard> > d_shards;
pdns::stat_t d_blockingQueryInserts;
pdns::stat_t d_blockingResponseInserts;
pdns::stat_t d_deferredQueryInserts;
pdns::stat_t d_deferredResponseInserts;
private:
size_t getShardId()
{
return (d_currentShardId++ % d_numberOfShards);
}
std::unique_ptr<Shard>& getOneShard()
{
return d_shards[getShardId()];
}
void insertQueryLocked(boost::circular_buffer<Query>& ring, const struct timespec& when, const ComboAddress& requestor, const DNSName& name, uint16_t qtype, uint16_t size, const struct dnsheader& dh, dnsdist::Protocol protocol)
{
if (!ring.full()) {
d_nbQueryEntries++;
}
ring.push_back({requestor, name, when, dh, size, qtype, protocol});
}
void insertResponseLocked(boost::circular_buffer<Response>& ring, const struct timespec& when, const ComboAddress& requestor, const DNSName& name, uint16_t qtype, unsigned int usec, unsigned int size, const struct dnsheader& dh, const ComboAddress& backend, dnsdist::Protocol protocol)
{
if (!ring.full()) {
d_nbResponseEntries++;
}
ring.push_back({requestor, backend, name, when, dh, usec, size, qtype, protocol});
}
std::atomic<size_t> d_nbQueryEntries;
std::atomic<size_t> d_nbResponseEntries;
std::atomic<size_t> d_currentShardId;
size_t d_numberOfShards;
size_t d_nbLockTries = 5;
bool d_keepLockingStats{false};
};
extern Rings g_rings;
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