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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.
*/
#include <sys/socket.h>
#include <sys/un.h>
#include "dnsdist-lua-network.hh"
#include "dolog.hh"
#include "threadname.hh"
namespace dnsdist
{
NetworkListener::NetworkListener() :
d_mplexer(std::unique_ptr<FDMultiplexer>(FDMultiplexer::getMultiplexerSilent(10)))
{
}
void NetworkListener::readCB(int desc, FDMultiplexer::funcparam_t& param)
{
auto cbData = boost::any_cast<std::shared_ptr<NetworkListener::CBData>>(param);
std::string packet;
#ifdef MSG_TRUNC
/* first we peek to avoid allocating a very large buffer. "MSG_TRUNC [...] return the real length of the datagram, even when it was longer than the passed buffer" */
auto peeked = recvfrom(desc, nullptr, 0, MSG_PEEK | MSG_TRUNC, nullptr, 0);
if (peeked > 0) {
packet.resize(static_cast<size_t>(peeked));
}
#endif
if (packet.size() == 0) {
packet.resize(65535);
}
struct sockaddr_un from;
memset(&from, 0, sizeof(from));
socklen_t fromLen = sizeof(from);
auto got = recvfrom(desc, &packet.at(0), packet.size(), 0, reinterpret_cast<sockaddr*>(&from), &fromLen);
if (got > 0) {
packet.resize(static_cast<size_t>(got));
std::string fromAddr;
if (fromLen <= sizeof(from)) {
fromAddr = std::string(from.sun_path, strlen(from.sun_path));
}
try {
cbData->d_cb(cbData->d_endpoint, std::move(packet), fromAddr);
}
catch (const std::exception& e) {
vinfolog("Exception in the read callback of a NetworkListener: %s", e.what());
}
catch (...) {
vinfolog("Exception in the read callback of a NetworkListener");
}
}
}
bool NetworkListener::addUnixListeningEndpoint(const std::string& path, NetworkListener::EndpointID id, NetworkListener::NetworkDatagramCB cb)
{
if (d_running == true) {
throw std::runtime_error("NetworkListener should not be altered at runtime");
}
struct sockaddr_un sun;
if (makeUNsockaddr(path, &sun) != 0) {
throw std::runtime_error("Invalid Unix socket path '" + path + "'");
}
bool abstractPath = path.at(0) == '\0';
if (!abstractPath) {
int err = unlink(path.c_str());
if (err != 0) {
err = errno;
if (err != ENOENT) {
vinfolog("Error removing Unix socket to path '%s': %s", path, stringerror(err));
}
}
}
Socket sock(sun.sun_family, SOCK_DGRAM, 0);
socklen_t sunLength = sizeof(sun);
if (abstractPath) {
/* abstract paths can contain null bytes so we need to set the actual size */
sunLength = sizeof(sa_family_t) + path.size();
}
if (bind(sock.getHandle(), reinterpret_cast<const struct sockaddr*>(&sun), sunLength) != 0) {
std::string sanitizedPath(path);
if (abstractPath) {
sanitizedPath[0] = '@';
}
throw std::runtime_error("Error binding Unix socket to path '" + sanitizedPath + "': " + stringerror());
}
sock.setNonBlocking();
auto cbData = std::make_shared<CBData>();
cbData->d_endpoint = id;
cbData->d_cb = cb;
d_mplexer->addReadFD(sock.getHandle(), readCB, cbData);
d_sockets.insert({path, std::move(sock)});
return true;
}
void NetworkListener::runOnce(struct timeval& now, uint32_t timeout)
{
d_running = true;
if (d_sockets.empty()) {
throw runtime_error("NetworkListener started with no sockets");
}
d_mplexer->run(&now, timeout);
}
void NetworkListener::mainThread()
{
setThreadName("dnsdist/lua-net");
struct timeval now;
while (true) {
runOnce(now, -1);
}
}
void NetworkListener::start()
{
std::thread main = std::thread([this] {
mainThread();
});
main.detach();
}
NetworkEndpoint::NetworkEndpoint(const std::string& path) :
d_socket(AF_UNIX, SOCK_DGRAM, 0)
{
struct sockaddr_un sun;
if (makeUNsockaddr(path, &sun) != 0) {
throw std::runtime_error("Invalid Unix socket path '" + path + "'");
}
socklen_t sunLength = sizeof(sun);
bool abstractPath = path.at(0) == '\0';
if (abstractPath) {
/* abstract paths can contain null bytes so we need to set the actual size */
sunLength = sizeof(sa_family_t) + path.size();
}
if (connect(d_socket.getHandle(), reinterpret_cast<const struct sockaddr*>(&sun), sunLength) != 0) {
std::string sanitizedPath(path);
if (abstractPath) {
sanitizedPath[0] = '@';
}
throw std::runtime_error("Error connecting Unix socket to path '" + sanitizedPath + "': " + stringerror());
}
d_socket.setNonBlocking();
}
bool NetworkEndpoint::send(const std::string_view& payload) const
{
auto sent = ::send(d_socket.getHandle(), payload.data(), payload.size(), 0);
if (sent <= 0) {
return false;
}
return static_cast<size_t>(sent) == payload.size();
}
}
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