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nghttp2/src/shrpx_memcached_connection.cc

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/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2015 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "shrpx_memcached_connection.h"
#include <limits.h>
#include <sys/uio.h>
#include <cerrno>
#include "shrpx_memcached_request.h"
#include "shrpx_memcached_result.h"
#include "shrpx_config.h"
#include "shrpx_tls.h"
#include "shrpx_log.h"
#include "util.h"
namespace shrpx {
namespace {
void timeoutcb(struct ev_loop *loop, ev_timer *w, int revents) {
auto conn = static_cast<Connection *>(w->data);
auto mconn = static_cast<MemcachedConnection *>(conn->data);
if (w == &conn->rt && !conn->expired_rt()) {
return;
}
if (LOG_ENABLED(INFO)) {
MCLOG(INFO, mconn) << "Time out";
}
mconn->disconnect();
}
} // namespace
namespace {
void readcb(struct ev_loop *loop, ev_io *w, int revents) {
auto conn = static_cast<Connection *>(w->data);
auto mconn = static_cast<MemcachedConnection *>(conn->data);
if (mconn->on_read() != 0) {
mconn->reconnect_or_fail();
return;
}
}
} // namespace
namespace {
void writecb(struct ev_loop *loop, ev_io *w, int revents) {
auto conn = static_cast<Connection *>(w->data);
auto mconn = static_cast<MemcachedConnection *>(conn->data);
if (mconn->on_write() != 0) {
mconn->reconnect_or_fail();
return;
}
}
} // namespace
namespace {
void connectcb(struct ev_loop *loop, ev_io *w, int revents) {
auto conn = static_cast<Connection *>(w->data);
auto mconn = static_cast<MemcachedConnection *>(conn->data);
if (mconn->connected() != 0) {
mconn->disconnect();
return;
}
writecb(loop, w, revents);
}
} // namespace
constexpr auto write_timeout = 10_s;
constexpr auto read_timeout = 10_s;
MemcachedConnection::MemcachedConnection(const Address *addr,
struct ev_loop *loop, SSL_CTX *ssl_ctx,
const StringRef &sni_name,
MemchunkPool *mcpool,
std::mt19937 &gen)
: conn_(loop, -1, nullptr, mcpool, write_timeout, read_timeout, {}, {},
connectcb, readcb, timeoutcb, this, 0, 0., Proto::MEMCACHED),
do_read_(&MemcachedConnection::noop),
do_write_(&MemcachedConnection::noop),
sni_name_(sni_name),
connect_blocker_(
gen, loop, [] {}, [] {}),
parse_state_{},
addr_(addr),
ssl_ctx_(ssl_ctx),
sendsum_(0),
try_count_(0),
connected_(false) {}
MemcachedConnection::~MemcachedConnection() { conn_.disconnect(); }
namespace {
void clear_request(std::deque<std::unique_ptr<MemcachedRequest>> &q) {
for (auto &req : q) {
if (req->cb) {
req->cb(req.get(),
MemcachedResult(MemcachedStatusCode::EXT_NETWORK_ERROR));
}
}
q.clear();
}
} // namespace
void MemcachedConnection::disconnect() {
clear_request(recvq_);
clear_request(sendq_);
sendbufv_.clear();
sendsum_ = 0;
parse_state_ = {};
connected_ = false;
conn_.disconnect();
assert(recvbuf_.rleft() == 0);
recvbuf_.reset();
do_read_ = do_write_ = &MemcachedConnection::noop;
}
int MemcachedConnection::initiate_connection() {
assert(conn_.fd == -1);
if (ssl_ctx_) {
auto ssl = tls::create_ssl(ssl_ctx_);
if (!ssl) {
return -1;
}
conn_.set_ssl(ssl);
conn_.tls.client_session_cache = &tls_session_cache_;
}
conn_.fd = util::create_nonblock_socket(addr_->su.storage.ss_family);
if (conn_.fd == -1) {
auto error = errno;
MCLOG(WARN, this) << "socket() failed; errno=" << error;
return -1;
}
int rv;
rv = connect(conn_.fd, &addr_->su.sa, addr_->len);
if (rv != 0 && errno != EINPROGRESS) {
auto error = errno;
MCLOG(WARN, this) << "connect() failed; errno=" << error;
close(conn_.fd);
conn_.fd = -1;
return -1;
}
if (ssl_ctx_) {
if (!util::numeric_host(sni_name_.c_str())) {
SSL_set_tlsext_host_name(conn_.tls.ssl, sni_name_.c_str());
}
auto session = tls::reuse_tls_session(tls_session_cache_);
if (session) {
SSL_set_session(conn_.tls.ssl, session);
SSL_SESSION_free(session);
}
conn_.prepare_client_handshake();
}
if (LOG_ENABLED(INFO)) {
MCLOG(INFO, this) << "Connecting to memcached server";
}
ev_io_set(&conn_.wev, conn_.fd, EV_WRITE);
ev_io_set(&conn_.rev, conn_.fd, EV_READ);
ev_set_cb(&conn_.wev, connectcb);
conn_.wlimit.startw();
ev_timer_again(conn_.loop, &conn_.wt);
return 0;
}
int MemcachedConnection::connected() {
auto sock_error = util::get_socket_error(conn_.fd);
if (sock_error != 0) {
MCLOG(WARN, this) << "memcached connect failed; addr="
<< util::to_numeric_addr(addr_)
<< ": errno=" << sock_error;
connect_blocker_.on_failure();
conn_.wlimit.stopw();
return -1;
}
if (LOG_ENABLED(INFO)) {
MCLOG(INFO, this) << "connected to memcached server";
}
conn_.rlimit.startw();
ev_set_cb(&conn_.wev, writecb);
if (conn_.tls.ssl) {
conn_.again_rt();
do_read_ = &MemcachedConnection::tls_handshake;
do_write_ = &MemcachedConnection::tls_handshake;
return 0;
}
ev_timer_stop(conn_.loop, &conn_.wt);
connected_ = true;
connect_blocker_.on_success();
do_read_ = &MemcachedConnection::read_clear;
do_write_ = &MemcachedConnection::write_clear;
return 0;
}
int MemcachedConnection::on_write() { return do_write_(*this); }
int MemcachedConnection::on_read() { return do_read_(*this); }
int MemcachedConnection::tls_handshake() {
ERR_clear_error();
conn_.last_read = ev_now(conn_.loop);
auto rv = conn_.tls_handshake();
if (rv == SHRPX_ERR_INPROGRESS) {
return 0;
}
if (rv < 0) {
connect_blocker_.on_failure();
return rv;
}
if (LOG_ENABLED(INFO)) {
LOG(INFO) << "SSL/TLS handshake completed";
}
auto &tlsconf = get_config()->tls;
if (!tlsconf.insecure &&
tls::check_cert(conn_.tls.ssl, addr_, sni_name_) != 0) {
connect_blocker_.on_failure();
return -1;
}
ev_timer_stop(conn_.loop, &conn_.rt);
ev_timer_stop(conn_.loop, &conn_.wt);
connected_ = true;
connect_blocker_.on_success();
do_read_ = &MemcachedConnection::read_tls;
do_write_ = &MemcachedConnection::write_tls;
return on_write();
}
int MemcachedConnection::write_tls() {
if (!connected_) {
return 0;
}
conn_.last_read = ev_now(conn_.loop);
std::array<struct iovec, MAX_WR_IOVCNT> iov;
std::array<uint8_t, 16_k> buf;
for (; !sendq_.empty();) {
auto iovcnt = fill_request_buffer(iov.data(), iov.size());
auto p = std::begin(buf);
for (size_t i = 0; i < iovcnt; ++i) {
auto &v = iov[i];
auto n = std::min(static_cast<size_t>(std::end(buf) - p), v.iov_len);
p = std::copy_n(static_cast<uint8_t *>(v.iov_base), n, p);
if (p == std::end(buf)) {
break;
}
}
auto nwrite = conn_.write_tls(buf.data(), p - std::begin(buf));
if (nwrite < 0) {
return -1;
}
if (nwrite == 0) {
return 0;
}
drain_send_queue(nwrite);
}
conn_.wlimit.stopw();
ev_timer_stop(conn_.loop, &conn_.wt);
return 0;
}
int MemcachedConnection::read_tls() {
if (!connected_) {
return 0;
}
conn_.last_read = ev_now(conn_.loop);
for (;;) {
auto nread = conn_.read_tls(recvbuf_.last, recvbuf_.wleft());
if (nread == 0) {
return 0;
}
if (nread < 0) {
return -1;
}
recvbuf_.write(nread);
if (parse_packet() != 0) {
return -1;
}
}
return 0;
}
int MemcachedConnection::write_clear() {
if (!connected_) {
return 0;
}
conn_.last_read = ev_now(conn_.loop);
std::array<struct iovec, MAX_WR_IOVCNT> iov;
for (; !sendq_.empty();) {
auto iovcnt = fill_request_buffer(iov.data(), iov.size());
auto nwrite = conn_.writev_clear(iov.data(), iovcnt);
if (nwrite < 0) {
return -1;
}
if (nwrite == 0) {
return 0;
}
drain_send_queue(nwrite);
}
conn_.wlimit.stopw();
ev_timer_stop(conn_.loop, &conn_.wt);
return 0;
}
int MemcachedConnection::read_clear() {
if (!connected_) {
return 0;
}
conn_.last_read = ev_now(conn_.loop);
for (;;) {
auto nread = conn_.read_clear(recvbuf_.last, recvbuf_.wleft());
if (nread == 0) {
return 0;
}
if (nread < 0) {
return -1;
}
recvbuf_.write(nread);
if (parse_packet() != 0) {
return -1;
}
}
return 0;
}
int MemcachedConnection::parse_packet() {
auto in = recvbuf_.pos;
for (;;) {
auto busy = false;
switch (parse_state_.state) {
case MemcachedParseState::HEADER24: {
if (recvbuf_.last - in < 24) {
recvbuf_.drain_reset(in - recvbuf_.pos);
return 0;
}
if (recvq_.empty()) {
MCLOG(WARN, this)
<< "Response received, but there is no in-flight request.";
return -1;
}
auto &req = recvq_.front();
if (*in != MEMCACHED_RES_MAGIC) {
MCLOG(WARN, this) << "Response has bad magic: "
<< static_cast<uint32_t>(*in);
return -1;
}
++in;
parse_state_.op = static_cast<MemcachedOp>(*in++);
parse_state_.keylen = util::get_uint16(in);
in += 2;
parse_state_.extralen = *in++;
// skip 1 byte reserved data type
++in;
parse_state_.status_code =
static_cast<MemcachedStatusCode>(util::get_uint16(in));
in += 2;
parse_state_.totalbody = util::get_uint32(in);
in += 4;
// skip 4 bytes opaque
in += 4;
parse_state_.cas = util::get_uint64(in);
in += 8;
if (req->op != parse_state_.op) {
MCLOG(WARN, this)
<< "opcode in response does not match to the request: want "
<< static_cast<uint32_t>(req->op) << ", got "
<< static_cast<uint32_t>(parse_state_.op);
return -1;
}
if (parse_state_.keylen != 0) {
MCLOG(WARN, this) << "zero length keylen expected: got "
<< parse_state_.keylen;
return -1;
}
if (parse_state_.totalbody > 16_k) {
MCLOG(WARN, this) << "totalbody is too large: got "
<< parse_state_.totalbody;
return -1;
}
if (parse_state_.op == MemcachedOp::GET &&
parse_state_.status_code == MemcachedStatusCode::NO_ERROR &&
parse_state_.extralen == 0) {
MCLOG(WARN, this) << "response for GET does not have extra";
return -1;
}
if (parse_state_.totalbody <
parse_state_.keylen + parse_state_.extralen) {
MCLOG(WARN, this) << "totalbody is too short: totalbody "
<< parse_state_.totalbody << ", want min "
<< parse_state_.keylen + parse_state_.extralen;
return -1;
}
if (parse_state_.extralen) {
parse_state_.state = MemcachedParseState::EXTRA;
parse_state_.read_left = parse_state_.extralen;
} else {
parse_state_.state = MemcachedParseState::VALUE;
parse_state_.read_left = parse_state_.totalbody - parse_state_.keylen -
parse_state_.extralen;
}
busy = true;
break;
}
case MemcachedParseState::EXTRA: {
// We don't use extra for now. Just read and forget.
auto n = std::min(static_cast<size_t>(recvbuf_.last - in),
parse_state_.read_left);
parse_state_.read_left -= n;
in += n;
if (parse_state_.read_left) {
recvbuf_.reset();
return 0;
}
parse_state_.state = MemcachedParseState::VALUE;
// since we require keylen == 0, totalbody - extralen ==
// valuelen
parse_state_.read_left =
parse_state_.totalbody - parse_state_.keylen - parse_state_.extralen;
busy = true;
break;
}
case MemcachedParseState::VALUE: {
auto n = std::min(static_cast<size_t>(recvbuf_.last - in),
parse_state_.read_left);
parse_state_.value.insert(std::end(parse_state_.value), in, in + n);
parse_state_.read_left -= n;
in += n;
if (parse_state_.read_left) {
recvbuf_.reset();
return 0;
}
if (LOG_ENABLED(INFO)) {
if (parse_state_.status_code != MemcachedStatusCode::NO_ERROR) {
MCLOG(INFO, this) << "response returned error status: "
<< static_cast<uint16_t>(parse_state_.status_code);
}
}
// We require at least one complete response to clear try count.
try_count_ = 0;
auto req = std::move(recvq_.front());
recvq_.pop_front();
if (sendq_.empty() && recvq_.empty()) {
ev_timer_stop(conn_.loop, &conn_.rt);
}
if (!req->canceled && req->cb) {
req->cb(req.get(), MemcachedResult(parse_state_.status_code,
std::move(parse_state_.value)));
}
parse_state_ = {};
break;
}
}
if (!busy && in == recvbuf_.last) {
break;
}
}
assert(in == recvbuf_.last);
recvbuf_.reset();
return 0;
}
#undef DEFAULT_WR_IOVCNT
#define DEFAULT_WR_IOVCNT 128
#if defined(IOV_MAX) && IOV_MAX < DEFAULT_WR_IOVCNT
# define MAX_WR_IOVCNT IOV_MAX
#else // !defined(IOV_MAX) || IOV_MAX >= DEFAULT_WR_IOVCNT
# define MAX_WR_IOVCNT DEFAULT_WR_IOVCNT
#endif // !defined(IOV_MAX) || IOV_MAX >= DEFAULT_WR_IOVCNT
size_t MemcachedConnection::fill_request_buffer(struct iovec *iov,
size_t iovlen) {
if (sendsum_ == 0) {
for (auto &req : sendq_) {
if (req->canceled) {
continue;
}
if (serialized_size(req.get()) + sendsum_ > 1300) {
break;
}
sendbufv_.emplace_back();
sendbufv_.back().req = req.get();
make_request(&sendbufv_.back(), req.get());
sendsum_ += sendbufv_.back().left();
}
if (sendsum_ == 0) {
sendq_.clear();
return 0;
}
}
size_t iovcnt = 0;
for (auto &buf : sendbufv_) {
if (iovcnt + 2 > iovlen) {
break;
}
auto req = buf.req;
if (buf.headbuf.rleft()) {
iov[iovcnt++] = {buf.headbuf.pos, buf.headbuf.rleft()};
}
if (buf.send_value_left) {
iov[iovcnt++] = {req->value.data() + req->value.size() -
buf.send_value_left,
buf.send_value_left};
}
}
return iovcnt;
}
void MemcachedConnection::drain_send_queue(size_t nwrite) {
sendsum_ -= nwrite;
while (nwrite > 0) {
auto &buf = sendbufv_.front();
auto &req = sendq_.front();
if (req->canceled) {
sendq_.pop_front();
continue;
}
assert(buf.req == req.get());
auto n = std::min(static_cast<size_t>(nwrite), buf.headbuf.rleft());
buf.headbuf.drain(n);
nwrite -= n;
n = std::min(static_cast<size_t>(nwrite), buf.send_value_left);
buf.send_value_left -= n;
nwrite -= n;
if (buf.headbuf.rleft() || buf.send_value_left) {
break;
}
sendbufv_.pop_front();
recvq_.push_back(std::move(sendq_.front()));
sendq_.pop_front();
}
// start read timer only when we wait for responses.
if (recvq_.empty()) {
ev_timer_stop(conn_.loop, &conn_.rt);
} else if (!ev_is_active(&conn_.rt)) {
conn_.again_rt();
}
}
size_t MemcachedConnection::serialized_size(MemcachedRequest *req) {
switch (req->op) {
case MemcachedOp::GET:
return 24 + req->key.size();
case MemcachedOp::ADD:
default:
return 24 + 8 + req->key.size() + req->value.size();
}
}
void MemcachedConnection::make_request(MemcachedSendbuf *sendbuf,
MemcachedRequest *req) {
auto &headbuf = sendbuf->headbuf;
std::fill(std::begin(headbuf.buf), std::end(headbuf.buf), 0);
headbuf[0] = MEMCACHED_REQ_MAGIC;
headbuf[1] = static_cast<uint8_t>(req->op);
switch (req->op) {
case MemcachedOp::GET:
util::put_uint16be(&headbuf[2], req->key.size());
util::put_uint32be(&headbuf[8], req->key.size());
headbuf.write(24);
break;
case MemcachedOp::ADD:
util::put_uint16be(&headbuf[2], req->key.size());
headbuf[4] = 8;
util::put_uint32be(&headbuf[8], 8 + req->key.size() + req->value.size());
util::put_uint32be(&headbuf[28], req->expiry);
headbuf.write(32);
break;
}
headbuf.write(req->key.c_str(), req->key.size());
sendbuf->send_value_left = req->value.size();
}
int MemcachedConnection::add_request(std::unique_ptr<MemcachedRequest> req) {
if (connect_blocker_.blocked()) {
return -1;
}
sendq_.push_back(std::move(req));
if (connected_) {
signal_write();
return 0;
}
if (conn_.fd == -1 && initiate_connection() != 0) {
connect_blocker_.on_failure();
disconnect();
return -1;
}
return 0;
}
// TODO should we start write timer too?
void MemcachedConnection::signal_write() { conn_.wlimit.startw(); }
int MemcachedConnection::noop() { return 0; }
void MemcachedConnection::reconnect_or_fail() {
if (!connected_ || (recvq_.empty() && sendq_.empty())) {
disconnect();
return;
}
constexpr size_t MAX_TRY_COUNT = 3;
if (++try_count_ >= MAX_TRY_COUNT) {
if (LOG_ENABLED(INFO)) {
MCLOG(INFO, this) << "Tried " << MAX_TRY_COUNT
<< " times, and all failed. Aborting";
}
try_count_ = 0;
disconnect();
return;
}
std::vector<std::unique_ptr<MemcachedRequest>> q;
q.reserve(recvq_.size() + sendq_.size());
if (LOG_ENABLED(INFO)) {
MCLOG(INFO, this) << "Retry connection, enqueue "
<< recvq_.size() + sendq_.size() << " request(s) again";
}
q.insert(std::end(q), std::make_move_iterator(std::begin(recvq_)),
std::make_move_iterator(std::end(recvq_)));
q.insert(std::end(q), std::make_move_iterator(std::begin(sendq_)),
std::make_move_iterator(std::end(sendq_)));
recvq_.clear();
sendq_.clear();
disconnect();
sendq_.insert(std::end(sendq_), std::make_move_iterator(std::begin(q)),
std::make_move_iterator(std::end(q)));
if (initiate_connection() != 0) {
connect_blocker_.on_failure();
disconnect();
return;
}
}
} // namespace shrpx
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