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#include <unistd.h>
#include "threadname.hh"
#include "remote_logger.hh"
#include <sys/uio.h>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef PDNS_CONFIG_ARGS
#include "logger.hh"
#define WE_ARE_RECURSOR
#else
#include "dolog.hh"
#endif
bool CircularWriteBuffer::hasRoomFor(const std::string& str) const
{
if (d_buffer.size() + 2 + str.size() > d_buffer.capacity()) {
return false;
}
return true;
}
bool CircularWriteBuffer::write(const std::string& str)
{
if (str.size() > std::numeric_limits<uint16_t>::max() || !hasRoomFor(str)) {
return false;
}
uint16_t len = htons(str.size());
const char* ptr = reinterpret_cast<const char*>(&len);
d_buffer.insert(d_buffer.end(), ptr, ptr + 2);
d_buffer.insert(d_buffer.end(), str.begin(), str.end());
return true;
}
bool CircularWriteBuffer::flush(int fd)
{
if (d_buffer.empty()) {
// not optional, we report EOF otherwise
return false;
}
auto arr1 = d_buffer.array_one();
auto arr2 = d_buffer.array_two();
struct iovec iov[2];
int pos = 0;
for(const auto& arr : {arr1, arr2}) {
if(arr.second) {
iov[pos].iov_base = arr.first;
iov[pos].iov_len = arr.second;
++pos;
}
}
ssize_t res = 0;
do {
res = writev(fd, iov, pos);
if (res < 0) {
if (errno == EINTR) {
continue;
}
if (errno == EAGAIN || errno == EWOULDBLOCK) {
return false;
}
/* we can't be sure we haven't sent a partial message,
and we don't want to send the remaining part after reconnecting */
d_buffer.clear();
throw std::runtime_error("Couldn't flush a thing: " + stringerror());
}
else if (!res) {
/* we can't be sure we haven't sent a partial message,
and we don't want to send the remaining part after reconnecting */
d_buffer.clear();
throw std::runtime_error("EOF");
}
}
while (res < 0);
if (static_cast<size_t>(res) == d_buffer.size()) {
d_buffer.clear();
}
else {
while (res--) {
d_buffer.pop_front();
}
}
return true;
}
RemoteLogger::RemoteLogger(const ComboAddress& remote, uint16_t timeout, uint64_t maxQueuedBytes, uint8_t reconnectWaitTime, bool asyncConnect): d_remote(remote), d_timeout(timeout), d_reconnectWaitTime(reconnectWaitTime), d_asyncConnect(asyncConnect), d_runtime({CircularWriteBuffer(maxQueuedBytes), nullptr})
{
if (!d_asyncConnect) {
reconnect();
}
d_thread = std::thread(&RemoteLogger::maintenanceThread, this);
}
bool RemoteLogger::reconnect()
{
try {
auto newSock = make_unique<Socket>(d_remote.sin4.sin_family, SOCK_STREAM, 0);
newSock->setNonBlocking();
newSock->connect(d_remote, d_timeout);
{
/* we are now successfully connected, time to take the lock and update the
socket */
auto runtime = d_runtime.lock();
runtime->d_socket = std::move(newSock);
}
}
catch (const std::exception& e) {
#ifdef WE_ARE_RECURSOR
g_log<<Logger::Warning<<"Error connecting to remote logger "<<d_remote.toStringWithPort()<<": "<<e.what()<<std::endl;
#else
warnlog("Error connecting to remote logger %s: %s", d_remote.toStringWithPort(), e.what());
#endif
return false;
}
return true;
}
void RemoteLogger::queueData(const std::string& data)
{
if (data.size() > std::numeric_limits<uint16_t>::max()) {
throw std::runtime_error("Got a request to write an object of size " + std::to_string(data.size()));
}
auto runtime = d_runtime.lock();
if (!runtime->d_writer.hasRoomFor(data)) {
/* not connected, queue is full, just drop */
if (!runtime->d_socket) {
++d_drops;
return;
}
try {
/* we try to flush some data */
if (!runtime->d_writer.flush(runtime->d_socket->getHandle())) {
/* but failed, let's just drop */
++d_drops;
return;
}
/* see if we freed enough data */
if (!runtime->d_writer.hasRoomFor(data)) {
/* we didn't */
++d_drops;
return;
}
}
catch(const std::exception& e) {
// cout << "Got exception writing: "<<e.what()<<endl;
++d_drops;
runtime->d_socket.reset();
return;
}
}
runtime->d_writer.write(data);
++d_processed;
}
void RemoteLogger::maintenanceThread()
{
try {
#ifdef WE_ARE_RECURSOR
string threadName = "pdns-r/remLog";
#else
string threadName = "dnsdist/remLog";
#endif
setThreadName(threadName);
for (;;) {
if (d_exiting) {
break;
}
bool connected = true;
if (d_runtime.lock()->d_socket == nullptr) {
// if it was unset, it will remain so, we are the only ones setting it!
connected = reconnect();
}
/* we will just go to sleep if the reconnection just failed */
if (connected) {
try {
/* we don't want to take the lock while trying to reconnect */
auto runtime = d_runtime.lock();
if (runtime->d_socket) { // check if it is set
/* if flush() returns false, it means that we couldn't flush anything yet
either because there is nothing to flush, or because the outgoing TCP
buffer is full. That's fine by us */
runtime->d_writer.flush(runtime->d_socket->getHandle());
}
else {
connected = false;
}
}
catch (const std::exception& e) {
d_runtime.lock()->d_socket.reset();
connected = false;
}
if (!connected) {
/* let's try to reconnect right away, we are about to sleep anyway */
reconnect();
}
}
sleep(d_reconnectWaitTime);
}
}
catch (const std::exception& e)
{
cerr << "Remote Logger's maintenance thead died on: " << e.what() << endl;
}
catch (...) {
cerr << "Remote Logger's maintenance thead died on unknown exception" << endl;
}
}
RemoteLogger::~RemoteLogger()
{
d_exiting = true;
d_thread.join();
}
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