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android / platform / external / grpc-grpc / cd4ff81b3f / . / src / core / lib / iomgr / tcp_posix.cc
blob: 4664d1a10d257cc254900f4086a21e531049b7bf [file] [log] [blame]
//
//
// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//
#include <grpc/support/port_platform.h>
#include <grpc/impl/grpc_types.h>
#include "src/core/lib/iomgr/exec_ctx.h"
#include "src/core/lib/iomgr/port.h"
#ifdef GRPC_POSIX_SOCKET_TCP
#include <errno.h>
#include <limits.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <unordered_map>
#include <grpc/slice.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include <grpc/support/sync.h>
#include <grpc/support/time.h>
#include "src/core/lib/address_utils/sockaddr_utils.h"
#include "src/core/lib/debug/event_log.h"
#include "src/core/lib/debug/stats.h"
#include "src/core/lib/debug/stats_data.h"
#include "src/core/lib/debug/trace.h"
#include "src/core/lib/experiments/experiments.h"
#include "src/core/lib/gpr/string.h"
#include "src/core/lib/gpr/useful.h"
#include "src/core/lib/gprpp/crash.h"
#include "src/core/lib/gprpp/strerror.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/iomgr/buffer_list.h"
#include "src/core/lib/iomgr/ev_posix.h"
#include "src/core/lib/iomgr/event_engine_shims/endpoint.h"
#include "src/core/lib/iomgr/executor.h"
#include "src/core/lib/iomgr/socket_utils_posix.h"
#include "src/core/lib/iomgr/tcp_posix.h"
#include "src/core/lib/resource_quota/api.h"
#include "src/core/lib/resource_quota/memory_quota.h"
#include "src/core/lib/resource_quota/trace.h"
#include "src/core/lib/slice/slice_internal.h"
#include "src/core/lib/slice/slice_string_helpers.h"
#ifndef SOL_TCP
#define SOL_TCP IPPROTO_TCP
#endif
#ifndef TCP_INQ
#define TCP_INQ 36
#define TCP_CM_INQ TCP_INQ
#endif
#ifdef GRPC_HAVE_MSG_NOSIGNAL
#define SENDMSG_FLAGS MSG_NOSIGNAL
#else
#define SENDMSG_FLAGS 0
#endif
// TCP zero copy sendmsg flag.
// NB: We define this here as a fallback in case we're using an older set of
// library headers that has not defined MSG_ZEROCOPY. Since this constant is
// part of the kernel, we are guaranteed it will never change/disagree so
// defining it here is safe.
#ifndef MSG_ZEROCOPY
#define MSG_ZEROCOPY 0x4000000
#endif
#ifdef GRPC_MSG_IOVLEN_TYPE
typedef GRPC_MSG_IOVLEN_TYPE msg_iovlen_type;
#else
typedef size_t msg_iovlen_type;
#endif
extern grpc_core::TraceFlag grpc_tcp_trace;
namespace grpc_core {
class TcpZerocopySendRecord {
public:
TcpZerocopySendRecord() { grpc_slice_buffer_init(&buf_); }
~TcpZerocopySendRecord() {
AssertEmpty();
grpc_slice_buffer_destroy(&buf_);
}
// Given the slices that we wish to send, and the current offset into the
// slice buffer (indicating which have already been sent), populate an iovec
// array that will be used for a zerocopy enabled sendmsg().
msg_iovlen_type PopulateIovs(size_t* unwind_slice_idx,
size_t* unwind_byte_idx, size_t* sending_length,
iovec* iov);
// A sendmsg() may not be able to send the bytes that we requested at this
// time, returning EAGAIN (possibly due to backpressure). In this case,
// unwind the offset into the slice buffer so we retry sending these bytes.
void UnwindIfThrottled(size_t unwind_slice_idx, size_t unwind_byte_idx) {
out_offset_.byte_idx = unwind_byte_idx;
out_offset_.slice_idx = unwind_slice_idx;
}
// Update the offset into the slice buffer based on how much we wanted to sent
// vs. what sendmsg() actually sent (which may be lower, possibly due to
// backpressure).
void UpdateOffsetForBytesSent(size_t sending_length, size_t actually_sent);
// Indicates whether all underlying data has been sent or not.
bool AllSlicesSent() { return out_offset_.slice_idx == buf_.count; }
// Reset this structure for a new tcp_write() with zerocopy.
void PrepareForSends(grpc_slice_buffer* slices_to_send) {
AssertEmpty();
out_offset_.slice_idx = 0;
out_offset_.byte_idx = 0;
grpc_slice_buffer_swap(slices_to_send, &buf_);
Ref();
}
// References: 1 reference per sendmsg(), and 1 for the tcp_write().
void Ref() { ref_.fetch_add(1, std::memory_order_relaxed); }
// Unref: called when we get an error queue notification for a sendmsg(), if a
// sendmsg() failed or when tcp_write() is done.
bool Unref() {
const intptr_t prior = ref_.fetch_sub(1, std::memory_order_acq_rel);
GPR_DEBUG_ASSERT(prior > 0);
if (prior == 1) {
AllSendsComplete();
return true;
}
return false;
}
private:
struct OutgoingOffset {
size_t slice_idx = 0;
size_t byte_idx = 0;
};
void AssertEmpty() {
GPR_DEBUG_ASSERT(buf_.count == 0);
GPR_DEBUG_ASSERT(buf_.length == 0);
GPR_DEBUG_ASSERT(ref_.load(std::memory_order_relaxed) == 0);
}
// When all sendmsg() calls associated with this tcp_write() have been
// completed (ie. we have received the notifications for each sequence number
// for each sendmsg()) and all reference counts have been dropped, drop our
// reference to the underlying data since we no longer need it.
void AllSendsComplete() {
GPR_DEBUG_ASSERT(ref_.load(std::memory_order_relaxed) == 0);
grpc_slice_buffer_reset_and_unref(&buf_);
}
grpc_slice_buffer buf_;
std::atomic<intptr_t> ref_{0};
OutgoingOffset out_offset_;
};
class TcpZerocopySendCtx {
public:
static constexpr int kDefaultMaxSends = 4;
static constexpr size_t kDefaultSendBytesThreshold = 16 * 1024; // 16KB
explicit TcpZerocopySendCtx(
int max_sends = kDefaultMaxSends,
size_t send_bytes_threshold = kDefaultSendBytesThreshold)
: max_sends_(max_sends),
free_send_records_size_(max_sends),
threshold_bytes_(send_bytes_threshold) {
send_records_ = static_cast<TcpZerocopySendRecord*>(
gpr_malloc(max_sends * sizeof(*send_records_)));
free_send_records_ = static_cast<TcpZerocopySendRecord**>(
gpr_malloc(max_sends * sizeof(*free_send_records_)));
if (send_records_ == nullptr || free_send_records_ == nullptr) {
gpr_free(send_records_);
gpr_free(free_send_records_);
gpr_log(GPR_INFO, "Disabling TCP TX zerocopy due to memory pressure.\n");
memory_limited_ = true;
} else {
for (int idx = 0; idx < max_sends_; ++idx) {
new (send_records_ + idx) TcpZerocopySendRecord();
free_send_records_[idx] = send_records_ + idx;
}
}
}
~TcpZerocopySendCtx() {
if (send_records_ != nullptr) {
for (int idx = 0; idx < max_sends_; ++idx) {
send_records_[idx].~TcpZerocopySendRecord();
}
}
gpr_free(send_records_);
gpr_free(free_send_records_);
}
// True if we were unable to allocate the various bookkeeping structures at
// transport initialization time. If memory limited, we do not zerocopy.
bool memory_limited() const { return memory_limited_; }
// TCP send zerocopy maintains an implicit sequence number for every
// successful sendmsg() with zerocopy enabled; the kernel later gives us an
// error queue notification with this sequence number indicating that the
// underlying data buffers that we sent can now be released. Once that
// notification is received, we can release the buffers associated with this
// zerocopy send record. Here, we associate the sequence number with the data
// buffers that were sent with the corresponding call to sendmsg().
void NoteSend(TcpZerocopySendRecord* record) {
record->Ref();
{
MutexLock guard(&lock_);
is_in_write_ = true;
AssociateSeqWithSendRecordLocked(last_send_, record);
}
++last_send_;
}
// If sendmsg() actually failed, though, we need to revert the sequence number
// that we speculatively bumped before calling sendmsg(). Note that we bump
// this sequence number and perform relevant bookkeeping (see: NoteSend())
// *before* calling sendmsg() since, if we called it *after* sendmsg(), then
// there is a possible race with the release notification which could occur on
// another thread before we do the necessary bookkeeping. Hence, calling
// NoteSend() *before* sendmsg() and implementing an undo function is needed.
void UndoSend() {
--last_send_;
if (ReleaseSendRecord(last_send_)->Unref()) {
// We should still be holding the ref taken by tcp_write().
GPR_DEBUG_ASSERT(0);
}
}
// Simply associate this send record (and the underlying sent data buffers)
// with the implicit sequence number for this zerocopy sendmsg().
void AssociateSeqWithSendRecordLocked(uint32_t seq,
TcpZerocopySendRecord* record) {
ctx_lookup_.emplace(seq, record);
}
// Get a send record for a send that we wish to do with zerocopy.
TcpZerocopySendRecord* GetSendRecord() {
MutexLock guard(&lock_);
return TryGetSendRecordLocked();
}
// A given send record corresponds to a single tcp_write() with zerocopy
// enabled. This can result in several sendmsg() calls to flush all of the
// data to wire. Each sendmsg() takes a reference on the
// TcpZerocopySendRecord, and corresponds to a single sequence number.
// ReleaseSendRecord releases a reference on TcpZerocopySendRecord for a
// single sequence number. This is called either when we receive the relevant
// error queue notification (saying that we can discard the underlying
// buffers for this sendmsg()) is received from the kernel - or, in case
// sendmsg() was unsuccessful to begin with.
TcpZerocopySendRecord* ReleaseSendRecord(uint32_t seq) {
MutexLock guard(&lock_);
return ReleaseSendRecordLocked(seq);
}
// After all the references to a TcpZerocopySendRecord are released, we can
// add it back to the pool (of size max_sends_). Note that we can only have
// max_sends_ tcp_write() instances with zerocopy enabled in flight at the
// same time.
void PutSendRecord(TcpZerocopySendRecord* record) {
GPR_DEBUG_ASSERT(record >= send_records_ &&
record < send_records_ + max_sends_);
MutexLock guard(&lock_);
PutSendRecordLocked(record);
}
// Indicate that we are disposing of this zerocopy context. This indicator
// will prevent new zerocopy writes from being issued.
void Shutdown() { shutdown_.store(true, std::memory_order_release); }
// Indicates that there are no inflight tcp_write() instances with zerocopy
// enabled.
bool AllSendRecordsEmpty() {
MutexLock guard(&lock_);
return free_send_records_size_ == max_sends_;
}
bool enabled() const { return enabled_; }
void set_enabled(bool enabled) {
GPR_DEBUG_ASSERT(!enabled || !memory_limited());
enabled_ = enabled;
}
// Only use zerocopy if we are sending at least this many bytes. The
// additional overhead of reading the error queue for notifications means that
// zerocopy is not useful for small transfers.
size_t threshold_bytes() const { return threshold_bytes_; }
// Expected to be called by handler reading messages from the err queue.
// It is used to indicate that some OMem meory is now available. It returns
// true to tell the caller to mark the file descriptor as immediately
// writable.
//
// If a write is currently in progress on the socket (ie. we have issued a
// sendmsg() and are about to check its return value) then we set omem state
// to CHECK to make the sending thread know that some tcp_omem was
// concurrently freed even if sendmsg() returns ENOBUFS. In this case, since
// there is already an active send thread, we do not need to mark the
// socket writeable, so we return false.
//
// If there was no write in progress on the socket, and the socket was not
// marked as FULL, then we need not mark the socket writeable now that some
// tcp_omem memory is freed since it was not considered as blocked on
// tcp_omem to begin with. So in this case, return false.
//
// But, if a write was not in progress and the omem state was FULL, then we
// need to mark the socket writeable since it is no longer blocked by
// tcp_omem. In this case, return true.
//
// Please refer to the STATE TRANSITION DIAGRAM below for more details.
//
bool UpdateZeroCopyOMemStateAfterFree() {
MutexLock guard(&lock_);
if (is_in_write_) {
zcopy_enobuf_state_ = OMemState::CHECK;
return false;
}
GPR_DEBUG_ASSERT(zcopy_enobuf_state_ != OMemState::CHECK);
if (zcopy_enobuf_state_ == OMemState::FULL) {
// A previous sendmsg attempt was blocked by ENOBUFS. Return true to
// mark the fd as writable so the next write attempt could be made.
zcopy_enobuf_state_ = OMemState::OPEN;
return true;
} else if (zcopy_enobuf_state_ == OMemState::OPEN) {
// No need to mark the fd as writable because the previous write
// attempt did not encounter ENOBUFS.
return false;
} else {
// This state should never be reached because it implies that the previous
// state was CHECK and is_in_write is false. This means that after the
// previous sendmsg returned and set is_in_write to false, it did
// not update the z-copy change from CHECK to OPEN.
Crash("OMem state error!");
}
}
// Expected to be called by the thread calling sendmsg after the syscall
// invocation. is complete. If an ENOBUF is seen, it checks if the error
// handler (Tx0cp completions) has already run and free'ed up some OMem. It
// returns true indicating that the write can be attempted again immediately.
// If ENOBUFS was seen but no Tx0cp completions have been received between the
// sendmsg() and us taking this lock, then tcp_omem is still full from our
// point of view. Therefore, we do not signal that the socket is writeable
// with respect to the availability of tcp_omem. Therefore the function
// returns false. This indicates that another write should not be attempted
// immediately and the calling thread should wait until the socket is writable
// again. If ENOBUFS was not seen, then again return false because the next
// write should be attempted only when the socket is writable again.
//
// Please refer to the STATE TRANSITION DIAGRAM below for more details.
//
bool UpdateZeroCopyOMemStateAfterSend(bool seen_enobuf) {
MutexLock guard(&lock_);
is_in_write_ = false;
if (seen_enobuf) {
if (zcopy_enobuf_state_ == OMemState::CHECK) {
zcopy_enobuf_state_ = OMemState::OPEN;
return true;
} else {
zcopy_enobuf_state_ = OMemState::FULL;
}
} else if (zcopy_enobuf_state_ != OMemState::OPEN) {
zcopy_enobuf_state_ = OMemState::OPEN;
}
return false;
}
private:
// STATE TRANSITION DIAGRAM
//
// sendmsg succeeds Tx-zero copy succeeds and there is no active sendmsg
// ----<<--+ +------<<-------------------------------------+
// | | | |
// | | v sendmsg returns ENOBUFS |
// +-----> OPEN ------------->>-------------------------> FULL
// ^ |
// | |
// | sendmsg completes |
// +----<<---------- CHECK <-------<<-------------+
// Tx-zero copy succeeds and there is
// an active sendmsg
//
enum class OMemState : int8_t {
OPEN, // Everything is clear and omem is not full.
FULL, // The last sendmsg() has returned with an errno of ENOBUFS.
CHECK, // Error queue is read while is_in_write_ was true, so we should
// check this state after the sendmsg.
};
TcpZerocopySendRecord* ReleaseSendRecordLocked(uint32_t seq) {
auto iter = ctx_lookup_.find(seq);
GPR_DEBUG_ASSERT(iter != ctx_lookup_.end());
TcpZerocopySendRecord* record = iter->second;
ctx_lookup_.erase(iter);
return record;
}
TcpZerocopySendRecord* TryGetSendRecordLocked() {
if (shutdown_.load(std::memory_order_acquire)) {
return nullptr;
}
if (free_send_records_size_ == 0) {
return nullptr;
}
free_send_records_size_--;
return free_send_records_[free_send_records_size_];
}
void PutSendRecordLocked(TcpZerocopySendRecord* record) {
GPR_DEBUG_ASSERT(free_send_records_size_ < max_sends_);
free_send_records_[free_send_records_size_] = record;
free_send_records_size_++;
}
TcpZerocopySendRecord* send_records_;
TcpZerocopySendRecord** free_send_records_;
int max_sends_;
int free_send_records_size_;
Mutex lock_;
uint32_t last_send_ = 0;
std::atomic<bool> shutdown_{false};
bool enabled_ = false;
size_t threshold_bytes_ = kDefaultSendBytesThreshold;
std::unordered_map<uint32_t, TcpZerocopySendRecord*> ctx_lookup_;
bool memory_limited_ = false;
bool is_in_write_ = false;
OMemState zcopy_enobuf_state_;
};
} // namespace grpc_core
using grpc_core::TcpZerocopySendCtx;
using grpc_core::TcpZerocopySendRecord;
namespace {
struct grpc_tcp {
explicit grpc_tcp(const grpc_core::PosixTcpOptions& tcp_options)
: min_read_chunk_size(tcp_options.tcp_min_read_chunk_size),
max_read_chunk_size(tcp_options.tcp_max_read_chunk_size),
tcp_zerocopy_send_ctx(
tcp_options.tcp_tx_zerocopy_max_simultaneous_sends,
tcp_options.tcp_tx_zerocopy_send_bytes_threshold) {}
grpc_endpoint base;
grpc_fd* em_fd;
int fd;
// Used by the endpoint read function to distinguish the very first read call
// from the rest
bool is_first_read;
bool has_posted_reclaimer ABSL_GUARDED_BY(read_mu) = false;
double target_length;
double bytes_read_this_round;
grpc_core::RefCount refcount;
gpr_atm shutdown_count;
int min_read_chunk_size;
int max_read_chunk_size;
int set_rcvlowat = 0;
// garbage after the last read
grpc_slice_buffer last_read_buffer;
grpc_core::Mutex read_mu;
grpc_slice_buffer* incoming_buffer ABSL_GUARDED_BY(read_mu) = nullptr;
int inq; // bytes pending on the socket from the last read.
bool inq_capable; // cache whether kernel supports inq
grpc_slice_buffer* outgoing_buffer;
// byte within outgoing_buffer->slices[0] to write next
size_t outgoing_byte_idx;
grpc_closure* read_cb;
grpc_closure* write_cb;
grpc_closure* release_fd_cb;
int* release_fd;
grpc_closure read_done_closure;
grpc_closure write_done_closure;
grpc_closure error_closure;
std::string peer_string;
std::string local_address;
grpc_core::MemoryOwner memory_owner;
grpc_core::MemoryAllocator::Reservation self_reservation;
grpc_core::TracedBufferList tb_list; // List of traced buffers
// grpc_endpoint_write takes an argument which if non-null means that the
// transport layer wants the TCP layer to collect timestamps for this write.
// This arg is forwarded to the timestamps callback function when the ACK
// timestamp is received from the kernel. This arg is a (void *) which allows
// users of this API to pass in a pointer to any kind of structure. This
// structure could actually be a tag or any book-keeping object that the user
// can use to distinguish between different traced writes. The only
// requirement from the TCP endpoint layer is that this arg should be non-null
// if the user wants timestamps for the write.
void* outgoing_buffer_arg;
// A counter which starts at 0. It is initialized the first time the socket
// options for collecting timestamps are set, and is incremented with each
// byte sent.
int bytes_counter;
bool socket_ts_enabled; // True if timestamping options are set on the socket
//
bool ts_capable; // Cache whether we can set timestamping options
gpr_atm stop_error_notification; // Set to 1 if we do not want to be notified
// on errors anymore
TcpZerocopySendCtx tcp_zerocopy_send_ctx;
TcpZerocopySendRecord* current_zerocopy_send = nullptr;
int min_progress_size; // A hint from upper layers specifying the minimum
// number of bytes that need to be read to make
// meaningful progress
};
struct backup_poller {
gpr_mu* pollset_mu;
grpc_closure run_poller;
};
} // namespace
static void ZerocopyDisableAndWaitForRemaining(grpc_tcp* tcp);
#define BACKUP_POLLER_POLLSET(b) ((grpc_pollset*)((b) + 1))
static grpc_core::Mutex* g_backup_poller_mu = nullptr;
static int g_uncovered_notifications_pending
ABSL_GUARDED_BY(g_backup_poller_mu);
static backup_poller* g_backup_poller ABSL_GUARDED_BY(g_backup_poller_mu);
static void tcp_handle_read(void* arg /* grpc_tcp */, grpc_error_handle error);
static void tcp_handle_write(void* arg /* grpc_tcp */, grpc_error_handle error);
static void tcp_drop_uncovered_then_handle_write(void* arg /* grpc_tcp */,
grpc_error_handle error);
static void done_poller(void* bp, grpc_error_handle /*error_ignored*/) {
backup_poller* p = static_cast<backup_poller*>(bp);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p destroy", p);
}
grpc_pollset_destroy(BACKUP_POLLER_POLLSET(p));
gpr_free(p);
}
static void run_poller(void* bp, grpc_error_handle /*error_ignored*/) {
backup_poller* p = static_cast<backup_poller*>(bp);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p run", p);
}
gpr_mu_lock(p->pollset_mu);
grpc_core::Timestamp deadline =
grpc_core::Timestamp::Now() + grpc_core::Duration::Seconds(10);
GRPC_LOG_IF_ERROR(
"backup_poller:pollset_work",
grpc_pollset_work(BACKUP_POLLER_POLLSET(p), nullptr, deadline));
gpr_mu_unlock(p->pollset_mu);
g_backup_poller_mu->Lock();
// last "uncovered" notification is the ref that keeps us polling
if (g_uncovered_notifications_pending == 1) {
GPR_ASSERT(g_backup_poller == p);
g_backup_poller = nullptr;
g_uncovered_notifications_pending = 0;
g_backup_poller_mu->Unlock();
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p shutdown", p);
}
grpc_pollset_shutdown(BACKUP_POLLER_POLLSET(p),
GRPC_CLOSURE_INIT(&p->run_poller, done_poller, p,
grpc_schedule_on_exec_ctx));
} else {
g_backup_poller_mu->Unlock();
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p reschedule", p);
}
grpc_core::Executor::Run(&p->run_poller, absl::OkStatus(),
grpc_core::ExecutorType::DEFAULT,
grpc_core::ExecutorJobType::LONG);
}
}
static void drop_uncovered(grpc_tcp* /*tcp*/) {
int old_count;
backup_poller* p;
g_backup_poller_mu->Lock();
p = g_backup_poller;
old_count = g_uncovered_notifications_pending--;
g_backup_poller_mu->Unlock();
GPR_ASSERT(old_count > 1);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p uncover cnt %d->%d", p, old_count,
old_count - 1);
}
}
// gRPC API considers a Write operation to be done the moment it clears ‘flow
// control’ i.e., not necessarily sent on the wire. This means that the
// application MIGHT not call `grpc_completion_queue_next/pluck` in a timely
// manner when its `Write()` API is acked.
//
// We need to ensure that the fd is 'covered' (i.e being monitored by some
// polling thread and progress is made) and hence add it to a backup poller here
static void cover_self(grpc_tcp* tcp) {
backup_poller* p;
g_backup_poller_mu->Lock();
int old_count = 0;
if (g_uncovered_notifications_pending == 0) {
g_uncovered_notifications_pending = 2;
p = static_cast<backup_poller*>(
gpr_zalloc(sizeof(*p) + grpc_pollset_size()));
g_backup_poller = p;
grpc_pollset_init(BACKUP_POLLER_POLLSET(p), &p->pollset_mu);
g_backup_poller_mu->Unlock();
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p create", p);
}
grpc_core::Executor::Run(
GRPC_CLOSURE_INIT(&p->run_poller, run_poller, p, nullptr),
absl::OkStatus(), grpc_core::ExecutorType::DEFAULT,
grpc_core::ExecutorJobType::LONG);
} else {
old_count = g_uncovered_notifications_pending++;
p = g_backup_poller;
g_backup_poller_mu->Unlock();
}
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "BACKUP_POLLER:%p add %p cnt %d->%d", p, tcp,
old_count - 1, old_count);
}
grpc_pollset_add_fd(BACKUP_POLLER_POLLSET(p), tcp->em_fd);
}
static void notify_on_read(grpc_tcp* tcp) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p notify_on_read", tcp);
}
grpc_fd_notify_on_read(tcp->em_fd, &tcp->read_done_closure);
}
static void notify_on_write(grpc_tcp* tcp) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p notify_on_write", tcp);
}
if (!grpc_event_engine_run_in_background()) {
cover_self(tcp);
}
grpc_fd_notify_on_write(tcp->em_fd, &tcp->write_done_closure);
}
static void tcp_drop_uncovered_then_handle_write(void* arg,
grpc_error_handle error) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p got_write: %s", arg,
grpc_core::StatusToString(error).c_str());
}
drop_uncovered(static_cast<grpc_tcp*>(arg));
tcp_handle_write(arg, error);
}
static void add_to_estimate(grpc_tcp* tcp, size_t bytes) {
tcp->bytes_read_this_round += static_cast<double>(bytes);
}
static void finish_estimate(grpc_tcp* tcp) {
// If we read >80% of the target buffer in one read loop, increase the size
// of the target buffer to either the amount read, or twice its previous
// value
if (tcp->bytes_read_this_round > tcp->target_length * 0.8) {
tcp->target_length =
std::max(2 * tcp->target_length, tcp->bytes_read_this_round);
} else {
tcp->target_length =
0.99 * tcp->target_length + 0.01 * tcp->bytes_read_this_round;
}
tcp->bytes_read_this_round = 0;
}
static grpc_error_handle tcp_annotate_error(grpc_error_handle src_error,
grpc_tcp* tcp) {
return grpc_error_set_str(
grpc_error_set_int(
grpc_error_set_int(src_error, grpc_core::StatusIntProperty::kFd,
tcp->fd),
// All tcp errors are marked with UNAVAILABLE so that application may
// choose to retry.
grpc_core::StatusIntProperty::kRpcStatus, GRPC_STATUS_UNAVAILABLE),
grpc_core::StatusStrProperty::kTargetAddress, tcp->peer_string);
}
static void tcp_handle_read(void* arg /* grpc_tcp */, grpc_error_handle error);
static void tcp_handle_write(void* arg /* grpc_tcp */, grpc_error_handle error);
static void tcp_shutdown(grpc_endpoint* ep, grpc_error_handle why) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
ZerocopyDisableAndWaitForRemaining(tcp);
grpc_fd_shutdown(tcp->em_fd, why);
tcp->read_mu.Lock();
tcp->memory_owner.Reset();
tcp->read_mu.Unlock();
}
static void tcp_free(grpc_tcp* tcp) {
grpc_fd_orphan(tcp->em_fd, tcp->release_fd_cb, tcp->release_fd,
"tcp_unref_orphan");
grpc_slice_buffer_destroy(&tcp->last_read_buffer);
tcp->tb_list.Shutdown(tcp->outgoing_buffer_arg,
GRPC_ERROR_CREATE("endpoint destroyed"));
tcp->outgoing_buffer_arg = nullptr;
delete tcp;
}
#ifndef NDEBUG
#define TCP_UNREF(tcp, reason) tcp_unref((tcp), (reason), DEBUG_LOCATION)
#define TCP_REF(tcp, reason) tcp_ref((tcp), (reason), DEBUG_LOCATION)
static void tcp_unref(grpc_tcp* tcp, const char* reason,
const grpc_core::DebugLocation& debug_location) {
if (GPR_UNLIKELY(tcp->refcount.Unref(debug_location, reason))) {
tcp_free(tcp);
}
}
static void tcp_ref(grpc_tcp* tcp, const char* reason,
const grpc_core::DebugLocation& debug_location) {
tcp->refcount.Ref(debug_location, reason);
}
#else
#define TCP_UNREF(tcp, reason) tcp_unref((tcp))
#define TCP_REF(tcp, reason) tcp_ref((tcp))
static void tcp_unref(grpc_tcp* tcp) {
if (GPR_UNLIKELY(tcp->refcount.Unref())) {
tcp_free(tcp);
}
}
static void tcp_ref(grpc_tcp* tcp) { tcp->refcount.Ref(); }
#endif
static void tcp_destroy(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
if (grpc_event_engine_can_track_errors()) {
ZerocopyDisableAndWaitForRemaining(tcp);
gpr_atm_no_barrier_store(&tcp->stop_error_notification, true);
grpc_fd_set_error(tcp->em_fd);
}
tcp->read_mu.Lock();
tcp->memory_owner.Reset();
tcp->read_mu.Unlock();
TCP_UNREF(tcp, "destroy");
}
static void perform_reclamation(grpc_tcp* tcp)
ABSL_LOCKS_EXCLUDED(tcp->read_mu) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_resource_quota_trace)) {
gpr_log(GPR_INFO, "TCP: benign reclamation to free memory");
}
tcp->read_mu.Lock();
if (tcp->incoming_buffer != nullptr) {
grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
}
tcp->has_posted_reclaimer = false;
tcp->read_mu.Unlock();
}
static void maybe_post_reclaimer(grpc_tcp* tcp)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(tcp->read_mu) {
if (!tcp->has_posted_reclaimer) {
tcp->has_posted_reclaimer = true;
TCP_REF(tcp, "posted_reclaimer");
tcp->memory_owner.PostReclaimer(
grpc_core::ReclamationPass::kBenign,
[tcp](absl::optional<grpc_core::ReclamationSweep> sweep) {
if (sweep.has_value()) {
perform_reclamation(tcp);
}
TCP_UNREF(tcp, "posted_reclaimer");
});
}
}
static void tcp_trace_read(grpc_tcp* tcp, grpc_error_handle error)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(tcp->read_mu) {
grpc_closure* cb = tcp->read_cb;
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p call_cb %p %p:%p", tcp, cb, cb->cb, cb->cb_arg);
size_t i;
gpr_log(GPR_INFO, "READ %p (peer=%s) error=%s", tcp,
tcp->peer_string.c_str(), grpc_core::StatusToString(error).c_str());
if (gpr_should_log(GPR_LOG_SEVERITY_DEBUG)) {
for (i = 0; i < tcp->incoming_buffer->count; i++) {
char* dump = grpc_dump_slice(tcp->incoming_buffer->slices[i],
GPR_DUMP_HEX | GPR_DUMP_ASCII);
gpr_log(GPR_DEBUG, "READ DATA: %s", dump);
gpr_free(dump);
}
}
}
}
static void update_rcvlowat(grpc_tcp* tcp)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(tcp->read_mu) {
if (!grpc_core::IsTcpRcvLowatEnabled()) return;
// TODO(ctiller): Check if supported by OS.
// TODO(ctiller): Allow some adjustments instead of hardcoding things.
static constexpr int kRcvLowatMax = 16 * 1024 * 1024;
static constexpr int kRcvLowatThreshold = 16 * 1024;
int remaining = std::min(static_cast<int>(tcp->incoming_buffer->length),
tcp->min_progress_size);
remaining = std::min(remaining, kRcvLowatMax);
// Setting SO_RCVLOWAT for small quantities does not save on CPU.
if (remaining < 2 * kRcvLowatThreshold) {
remaining = 0;
}
// Decrement remaining by kRcvLowatThreshold. This would have the effect of
// waking up a little early. It would help with latency because some bytes
// may arrive while we execute the recvmsg syscall after waking up.
if (remaining > 0) {
remaining -= kRcvLowatThreshold;
}
// We still do not know the RPC size. Do not set SO_RCVLOWAT.
if (tcp->set_rcvlowat <= 1 && remaining <= 1) return;
// Previous value is still valid. No change needed in SO_RCVLOWAT.
if (tcp->set_rcvlowat == remaining) {
return;
}
if (setsockopt(tcp->fd, SOL_SOCKET, SO_RCVLOWAT, &remaining,
sizeof(remaining)) != 0) {
gpr_log(GPR_ERROR, "%s",
absl::StrCat("Cannot set SO_RCVLOWAT on fd=", tcp->fd,
" err=", grpc_core::StrError(errno).c_str())
.c_str());
return;
}
tcp->set_rcvlowat = remaining;
}
// Returns true if data available to read or error other than EAGAIN.
#define MAX_READ_IOVEC 64
static bool tcp_do_read(grpc_tcp* tcp, grpc_error_handle* error)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(tcp->read_mu) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p do_read", tcp);
}
struct msghdr msg;
struct iovec iov[MAX_READ_IOVEC];
ssize_t read_bytes;
size_t total_read_bytes = 0;
size_t iov_len =
std::min<size_t>(MAX_READ_IOVEC, tcp->incoming_buffer->count);
#ifdef GRPC_LINUX_ERRQUEUE
constexpr size_t cmsg_alloc_space =
CMSG_SPACE(sizeof(grpc_core::scm_timestamping)) + CMSG_SPACE(sizeof(int));
#else
constexpr size_t cmsg_alloc_space = 24 /* CMSG_SPACE(sizeof(int)) */;
#endif // GRPC_LINUX_ERRQUEUE
char cmsgbuf[cmsg_alloc_space];
for (size_t i = 0; i < iov_len; i++) {
iov[i].iov_base = GRPC_SLICE_START_PTR(tcp->incoming_buffer->slices[i]);
iov[i].iov_len = GRPC_SLICE_LENGTH(tcp->incoming_buffer->slices[i]);
}
GPR_ASSERT(tcp->incoming_buffer->length != 0);
GPR_DEBUG_ASSERT(tcp->min_progress_size > 0);
do {
// Assume there is something on the queue. If we receive TCP_INQ from
// kernel, we will update this value, otherwise, we have to assume there is
// always something to read until we get EAGAIN.
tcp->inq = 1;
msg.msg_name = nullptr;
msg.msg_namelen = 0;
msg.msg_iov = iov;
msg.msg_iovlen = static_cast<msg_iovlen_type>(iov_len);
if (tcp->inq_capable) {
msg.msg_control = cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
} else {
msg.msg_control = nullptr;
msg.msg_controllen = 0;
}
msg.msg_flags = 0;
grpc_core::global_stats().IncrementTcpReadOffer(
tcp->incoming_buffer->length);
grpc_core::global_stats().IncrementTcpReadOfferIovSize(
tcp->incoming_buffer->count);
do {
grpc_core::global_stats().IncrementSyscallRead();
read_bytes = recvmsg(tcp->fd, &msg, 0);
} while (read_bytes < 0 && errno == EINTR);
if (read_bytes < 0 && errno == EAGAIN) {
// NB: After calling call_read_cb a parallel call of the read handler may
// be running.
if (total_read_bytes > 0) {
break;
}
finish_estimate(tcp);
tcp->inq = 0;
return false;
}
// We have read something in previous reads. We need to deliver those
// bytes to the upper layer.
if (read_bytes <= 0 && total_read_bytes >= 1) {
tcp->inq = 1;
break;
}
if (read_bytes <= 0) {
// 0 read size ==> end of stream
grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
if (read_bytes == 0) {
*error = tcp_annotate_error(absl::InternalError("Socket closed"), tcp);
} else {
*error =
tcp_annotate_error(absl::InternalError(absl::StrCat(
"recvmsg:", grpc_core::StrError(errno))),
tcp);
}
return true;
}
grpc_core::global_stats().IncrementTcpReadSize(read_bytes);
add_to_estimate(tcp, static_cast<size_t>(read_bytes));
GPR_DEBUG_ASSERT((size_t)read_bytes <=
tcp->incoming_buffer->length - total_read_bytes);
#ifdef GRPC_HAVE_TCP_INQ
if (tcp->inq_capable) {
GPR_DEBUG_ASSERT(!(msg.msg_flags & MSG_CTRUNC));
struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
for (; cmsg != nullptr; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_TCP && cmsg->cmsg_type == TCP_CM_INQ &&
cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
tcp->inq = *reinterpret_cast<int*>(CMSG_DATA(cmsg));
break;
}
}
}
#endif // GRPC_HAVE_TCP_INQ
total_read_bytes += read_bytes;
if (tcp->inq == 0 || total_read_bytes == tcp->incoming_buffer->length) {
break;
}
// We had a partial read, and still have space to read more data.
// So, adjust IOVs and try to read more.
size_t remaining = read_bytes;
size_t j = 0;
for (size_t i = 0; i < iov_len; i++) {
if (remaining >= iov[i].iov_len) {
remaining -= iov[i].iov_len;
continue;
}
if (remaining > 0) {
iov[j].iov_base = static_cast<char*>(iov[i].iov_base) + remaining;
iov[j].iov_len = iov[i].iov_len - remaining;
remaining = 0;
} else {
iov[j].iov_base = iov[i].iov_base;
iov[j].iov_len = iov[i].iov_len;
}
++j;
}
iov_len = j;
} while (true);
if (tcp->inq == 0) {
finish_estimate(tcp);
}
GPR_DEBUG_ASSERT(total_read_bytes > 0);
*error = absl::OkStatus();
if (grpc_core::IsTcpFrameSizeTuningEnabled()) {
// Update min progress size based on the total number of bytes read in
// this round.
tcp->min_progress_size -= total_read_bytes;
if (tcp->min_progress_size > 0) {
// There is still some bytes left to be read before we can signal
// the read as complete. Append the bytes read so far into
// last_read_buffer which serves as a staging buffer. Return false
// to indicate tcp_handle_read needs to be scheduled again.
grpc_slice_buffer_move_first(tcp->incoming_buffer, total_read_bytes,
&tcp->last_read_buffer);
return false;
} else {
// The required number of bytes have been read. Append the bytes
// read in this round into last_read_buffer. Then swap last_read_buffer
// and incoming_buffer. Now incoming buffer contains all the bytes
// read since the start of the last tcp_read operation. last_read_buffer
// would contain any spare space left in the incoming buffer. This
// space will be used in the next tcp_read operation.
tcp->min_progress_size = 1;
grpc_slice_buffer_move_first(tcp->incoming_buffer, total_read_bytes,
&tcp->last_read_buffer);
grpc_slice_buffer_swap(&tcp->last_read_buffer, tcp->incoming_buffer);
return true;
}
}
if (total_read_bytes < tcp->incoming_buffer->length) {
grpc_slice_buffer_trim_end(tcp->incoming_buffer,
tcp->incoming_buffer->length - total_read_bytes,
&tcp->last_read_buffer);
}
return true;
}
static void maybe_make_read_slices(grpc_tcp* tcp)
ABSL_EXCLUSIVE_LOCKS_REQUIRED(tcp->read_mu) {
static const int kBigAlloc = 64 * 1024;
static const int kSmallAlloc = 8 * 1024;
if (tcp->incoming_buffer->length <
static_cast<size_t>(tcp->min_progress_size)) {
size_t allocate_length = tcp->min_progress_size;
const size_t target_length = static_cast<size_t>(tcp->target_length);
// If memory pressure is low and we think there will be more than
// min_progress_size bytes to read, allocate a bit more.
const bool low_memory_pressure =
tcp->memory_owner.GetPressureInfo().pressure_control_value < 0.8;
if (low_memory_pressure && target_length > allocate_length) {
allocate_length = target_length;
}
int extra_wanted =
allocate_length - static_cast<int>(tcp->incoming_buffer->length);
if (extra_wanted >=
(low_memory_pressure ? kSmallAlloc * 3 / 2 : kBigAlloc)) {
while (extra_wanted > 0) {
extra_wanted -= kBigAlloc;
grpc_slice_buffer_add_indexed(tcp->incoming_buffer,
tcp->memory_owner.MakeSlice(kBigAlloc));
grpc_core::global_stats().IncrementTcpReadAlloc64k();
}
} else {
while (extra_wanted > 0) {
extra_wanted -= kSmallAlloc;
grpc_slice_buffer_add_indexed(tcp->incoming_buffer,
tcp->memory_owner.MakeSlice(kSmallAlloc));
grpc_core::global_stats().IncrementTcpReadAlloc8k();
}
}
maybe_post_reclaimer(tcp);
}
}
static void tcp_handle_read(void* arg /* grpc_tcp */, grpc_error_handle error) {
grpc_tcp* tcp = static_cast<grpc_tcp*>(arg);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p got_read: %s", tcp,
grpc_core::StatusToString(error).c_str());
}
tcp->read_mu.Lock();
grpc_error_handle tcp_read_error;
if (GPR_LIKELY(error.ok()) && tcp->memory_owner.is_valid()) {
maybe_make_read_slices(tcp);
if (!tcp_do_read(tcp, &tcp_read_error)) {
// Maybe update rcv lowat value based on the number of bytes read in this
// round.
update_rcvlowat(tcp);
tcp->read_mu.Unlock();
// We've consumed the edge, request a new one
notify_on_read(tcp);
return;
}
tcp_trace_read(tcp, tcp_read_error);
} else {
if (!tcp->memory_owner.is_valid() && error.ok()) {
tcp_read_error =
tcp_annotate_error(absl::InternalError("Socket closed"), tcp);
} else {
tcp_read_error = error;
}
grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
}
// Update rcv lowat needs to be called at the end of the current read
// operation to ensure the right SO_RCVLOWAT value is set for the next read.
// Otherwise the next endpoint read operation may get stuck indefinitely
// because the previously set rcv lowat value will persist and the socket may
// erroneously considered to not be ready for read.
update_rcvlowat(tcp);
grpc_closure* cb = tcp->read_cb;
tcp->read_cb = nullptr;
tcp->incoming_buffer = nullptr;
tcp->read_mu.Unlock();
grpc_core::Closure::Run(DEBUG_LOCATION, cb, tcp_read_error);
TCP_UNREF(tcp, "read");
}
static void tcp_read(grpc_endpoint* ep, grpc_slice_buffer* incoming_buffer,
grpc_closure* cb, bool urgent, int min_progress_size) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
GPR_ASSERT(tcp->read_cb == nullptr);
tcp->read_cb = cb;
tcp->read_mu.Lock();
tcp->incoming_buffer = incoming_buffer;
tcp->min_progress_size = grpc_core::IsTcpFrameSizeTuningEnabled()
? std::max(min_progress_size, 1)
: 1;
grpc_slice_buffer_reset_and_unref(incoming_buffer);
grpc_slice_buffer_swap(incoming_buffer, &tcp->last_read_buffer);
TCP_REF(tcp, "read");
if (tcp->is_first_read) {
tcp->read_mu.Unlock();
// Endpoint read called for the very first time. Register read callback with
// the polling engine
tcp->is_first_read = false;
notify_on_read(tcp);
} else if (!urgent && tcp->inq == 0) {
tcp->read_mu.Unlock();
// Upper layer asked to read more but we know there is no pending data
// to read from previous reads. So, wait for POLLIN.
//
notify_on_read(tcp);
} else {
tcp->read_mu.Unlock();
// Not the first time. We may or may not have more bytes available. In any
// case call tcp->read_done_closure (i.e tcp_handle_read()) which does the
// right thing (i.e calls tcp_do_read() which either reads the available
// bytes or calls notify_on_read() to be notified when new bytes become
// available
grpc_core::Closure::Run(DEBUG_LOCATION, &tcp->read_done_closure,
absl::OkStatus());
}
}
// A wrapper around sendmsg. It sends \a msg over \a fd and returns the number
// of bytes sent.
ssize_t tcp_send(int fd, const struct msghdr* msg, int* saved_errno,
int additional_flags = 0) {
ssize_t sent_length;
do {
// TODO(klempner): Cork if this is a partial write
grpc_core::global_stats().IncrementSyscallWrite();
sent_length = sendmsg(fd, msg, SENDMSG_FLAGS | additional_flags);
} while (sent_length < 0 && (*saved_errno = errno) == EINTR);
return sent_length;
}
/// This is to be called if outgoing_buffer_arg is not null. On linux platforms,
/// this will call sendmsg with socket options set to collect timestamps inside
/// the kernel. On return, sent_length is set to the return value of the sendmsg
/// call. Returns false if setting the socket options failed. This is not
/// implemented for non-linux platforms currently, and crashes out.
///
static bool tcp_write_with_timestamps(grpc_tcp* tcp, struct msghdr* msg,
size_t sending_length,
ssize_t* sent_length, int* saved_errno,
int additional_flags = 0);
/// The callback function to be invoked when we get an error on the socket.
static void tcp_handle_error(void* arg /* grpc_tcp */, grpc_error_handle error);
static TcpZerocopySendRecord* tcp_get_send_zerocopy_record(
grpc_tcp* tcp, grpc_slice_buffer* buf);
#ifdef GRPC_LINUX_ERRQUEUE
static bool process_errors(grpc_tcp* tcp);
static TcpZerocopySendRecord* tcp_get_send_zerocopy_record(
grpc_tcp* tcp, grpc_slice_buffer* buf) {
TcpZerocopySendRecord* zerocopy_send_record = nullptr;
const bool use_zerocopy =
tcp->tcp_zerocopy_send_ctx.enabled() &&
tcp->tcp_zerocopy_send_ctx.threshold_bytes() < buf->length;
if (use_zerocopy) {
zerocopy_send_record = tcp->tcp_zerocopy_send_ctx.GetSendRecord();
if (zerocopy_send_record == nullptr) {
process_errors(tcp);
zerocopy_send_record = tcp->tcp_zerocopy_send_ctx.GetSendRecord();
}
if (zerocopy_send_record != nullptr) {
zerocopy_send_record->PrepareForSends(buf);
GPR_DEBUG_ASSERT(buf->count == 0);
GPR_DEBUG_ASSERT(buf->length == 0);
tcp->outgoing_byte_idx = 0;
tcp->outgoing_buffer = nullptr;
}
}
return zerocopy_send_record;
}
static void ZerocopyDisableAndWaitForRemaining(grpc_tcp* tcp) {
tcp->tcp_zerocopy_send_ctx.Shutdown();
while (!tcp->tcp_zerocopy_send_ctx.AllSendRecordsEmpty()) {
process_errors(tcp);
}
}
static bool tcp_write_with_timestamps(grpc_tcp* tcp, struct msghdr* msg,
size_t sending_length,
ssize_t* sent_length, int* saved_errno,
int additional_flags) {
if (!tcp->socket_ts_enabled) {
uint32_t opt = grpc_core::kTimestampingSocketOptions;
if (setsockopt(tcp->fd, SOL_SOCKET, SO_TIMESTAMPING,
static_cast<void*>(&opt), sizeof(opt)) != 0) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_ERROR, "Failed to set timestamping options on the socket.");
}
return false;
}
tcp->bytes_counter = -1;
tcp->socket_ts_enabled = true;
}
// Set control message to indicate that you want timestamps.
union {
char cmsg_buf[CMSG_SPACE(sizeof(uint32_t))];
struct cmsghdr align;
} u;
cmsghdr* cmsg = reinterpret_cast<cmsghdr*>(u.cmsg_buf);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SO_TIMESTAMPING;
cmsg->cmsg_len = CMSG_LEN(sizeof(uint32_t));
*reinterpret_cast<int*>(CMSG_DATA(cmsg)) =
grpc_core::kTimestampingRecordingOptions;
msg->msg_control = u.cmsg_buf;
msg->msg_controllen = CMSG_SPACE(sizeof(uint32_t));
// If there was an error on sendmsg the logic in tcp_flush will handle it.
ssize_t length = tcp_send(tcp->fd, msg, saved_errno, additional_flags);
*sent_length = length;
// Only save timestamps if all the bytes were taken by sendmsg.
if (sending_length == static_cast<size_t>(length)) {
tcp->tb_list.AddNewEntry(static_cast<uint32_t>(tcp->bytes_counter + length),
tcp->fd, tcp->outgoing_buffer_arg);
tcp->outgoing_buffer_arg = nullptr;
}
return true;
}
static void UnrefMaybePutZerocopySendRecord(grpc_tcp* tcp,
TcpZerocopySendRecord* record,
uint32_t seq, const char* tag);
// Reads \a cmsg to process zerocopy control messages.
static void process_zerocopy(grpc_tcp* tcp, struct cmsghdr* cmsg) {
GPR_DEBUG_ASSERT(cmsg);
auto serr = reinterpret_cast<struct sock_extended_err*>(CMSG_DATA(cmsg));
GPR_DEBUG_ASSERT(serr->ee_errno == 0);
GPR_DEBUG_ASSERT(serr->ee_origin == SO_EE_ORIGIN_ZEROCOPY);
const uint32_t lo = serr->ee_info;
const uint32_t hi = serr->ee_data;
for (uint32_t seq = lo; seq <= hi; ++seq) {
// TODO(arjunroy): It's likely that lo and hi refer to zerocopy sequence
// numbers that are generated by a single call to grpc_endpoint_write; ie.
// we can batch the unref operation. So, check if record is the same for
// both; if so, batch the unref/put.
TcpZerocopySendRecord* record =
tcp->tcp_zerocopy_send_ctx.ReleaseSendRecord(seq);
GPR_DEBUG_ASSERT(record);
UnrefMaybePutZerocopySendRecord(tcp, record, seq, "CALLBACK RCVD");
}
if (tcp->tcp_zerocopy_send_ctx.UpdateZeroCopyOMemStateAfterFree()) {
grpc_fd_set_writable(tcp->em_fd);
}
}
// Whether the cmsg received from error queue is of the IPv4 or IPv6 levels.
static bool CmsgIsIpLevel(const cmsghdr& cmsg) {
return (cmsg.cmsg_level == SOL_IPV6 && cmsg.cmsg_type == IPV6_RECVERR) ||
(cmsg.cmsg_level == SOL_IP && cmsg.cmsg_type == IP_RECVERR);
}
static bool CmsgIsZeroCopy(const cmsghdr& cmsg) {
if (!CmsgIsIpLevel(cmsg)) {
return false;
}
auto serr = reinterpret_cast<const sock_extended_err*> CMSG_DATA(&cmsg);
return serr->ee_errno == 0 && serr->ee_origin == SO_EE_ORIGIN_ZEROCOPY;
}
/// Reads \a cmsg to derive timestamps from the control messages. If a valid
/// timestamp is found, the traced buffer list is updated with this timestamp.
/// The caller of this function should be looping on the control messages found
/// in \a msg. \a cmsg should point to the control message that the caller wants
/// processed.
/// On return, a pointer to a control message is returned. On the next
/// iteration, CMSG_NXTHDR(msg, ret_val) should be passed as \a cmsg.
struct cmsghdr* process_timestamp(grpc_tcp* tcp, msghdr* msg,
struct cmsghdr* cmsg) {
auto next_cmsg = CMSG_NXTHDR(msg, cmsg);
cmsghdr* opt_stats = nullptr;
if (next_cmsg == nullptr) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_ERROR, "Received timestamp without extended error");
}
return cmsg;
}
// Check if next_cmsg is an OPT_STATS msg
if (next_cmsg->cmsg_level == SOL_SOCKET &&
next_cmsg->cmsg_type == SCM_TIMESTAMPING_OPT_STATS) {
opt_stats = next_cmsg;
next_cmsg = CMSG_NXTHDR(msg, opt_stats);
if (next_cmsg == nullptr) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_ERROR, "Received timestamp without extended error");
}
return opt_stats;
}
}
if (!(next_cmsg->cmsg_level == SOL_IP || next_cmsg->cmsg_level == SOL_IPV6) ||
!(next_cmsg->cmsg_type == IP_RECVERR ||
next_cmsg->cmsg_type == IPV6_RECVERR)) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_ERROR, "Unexpected control message");
}
return cmsg;
}
auto tss =
reinterpret_cast<struct grpc_core::scm_timestamping*>(CMSG_DATA(cmsg));
auto serr = reinterpret_cast<struct sock_extended_err*>(CMSG_DATA(next_cmsg));
if (serr->ee_errno != ENOMSG ||
serr->ee_origin != SO_EE_ORIGIN_TIMESTAMPING) {
gpr_log(GPR_ERROR, "Unexpected control message");
return cmsg;
}
tcp->tb_list.ProcessTimestamp(serr, opt_stats, tss);
return next_cmsg;
}
/// For linux platforms, reads the socket's error queue and processes error
/// messages from the queue.
///
static bool process_errors(grpc_tcp* tcp) {
bool processed_err = false;
struct iovec iov;
iov.iov_base = nullptr;
iov.iov_len = 0;
struct msghdr msg;
msg.msg_name = nullptr;
msg.msg_namelen = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 0;
msg.msg_flags = 0;
// Allocate enough space so we don't need to keep increasing this as size
// of OPT_STATS increase
constexpr size_t cmsg_alloc_space =
CMSG_SPACE(sizeof(grpc_core::scm_timestamping)) +
CMSG_SPACE(sizeof(sock_extended_err) + sizeof(sockaddr_in)) +
CMSG_SPACE(32 * NLA_ALIGN(NLA_HDRLEN + sizeof(uint64_t)));
// Allocate aligned space for cmsgs received along with timestamps
union {
char rbuf[cmsg_alloc_space];
struct cmsghdr align;
} aligned_buf;
msg.msg_control = aligned_buf.rbuf;
int r, saved_errno;
while (true) {
msg.msg_controllen = sizeof(aligned_buf.rbuf);
do {
r = recvmsg(tcp->fd, &msg, MSG_ERRQUEUE);
saved_errno = errno;
} while (r < 0 && saved_errno == EINTR);
if (r == -1 && saved_errno == EAGAIN) {
return processed_err; // No more errors to process
}
if (r == -1) {
return processed_err;
}
if (GPR_UNLIKELY((msg.msg_flags & MSG_CTRUNC) != 0)) {
gpr_log(GPR_ERROR, "Error message was truncated.");
}
if (msg.msg_controllen == 0) {
// There was no control message found. It was probably spurious.
return processed_err;
}
bool seen = false;
for (auto cmsg = CMSG_FIRSTHDR(&msg); cmsg && cmsg->cmsg_len;
cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (CmsgIsZeroCopy(*cmsg)) {
process_zerocopy(tcp, cmsg);
seen = true;
processed_err = true;
} else if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_TIMESTAMPING) {
cmsg = process_timestamp(tcp, &msg, cmsg);
seen = true;
processed_err = true;
} else {
// Got a control message that is not a timestamp or zerocopy. Don't know
// how to handle this.
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO,
"unknown control message cmsg_level:%d cmsg_type:%d",
cmsg->cmsg_level, cmsg->cmsg_type);
}
return processed_err;
}
}
if (!seen) {
return processed_err;
}
}
}
static void tcp_handle_error(void* arg /* grpc_tcp */,
grpc_error_handle error) {
grpc_tcp* tcp = static_cast<grpc_tcp*>(arg);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "TCP:%p got_error: %s", tcp,
grpc_core::StatusToString(error).c_str());
}
if (!error.ok() ||
static_cast<bool>(gpr_atm_acq_load(&tcp->stop_error_notification))) {
// We aren't going to register to hear on error anymore, so it is safe to
// unref.
TCP_UNREF(tcp, "error-tracking");
return;
}
// We are still interested in collecting timestamps, so let's try reading
// them.
bool processed = process_errors(tcp);
// This might not a timestamps error. Set the read and write closures to be
// ready.
if (!processed) {
grpc_fd_set_readable(tcp->em_fd);
grpc_fd_set_writable(tcp->em_fd);
}
grpc_fd_notify_on_error(tcp->em_fd, &tcp->error_closure);
}
#else // GRPC_LINUX_ERRQUEUE
static TcpZerocopySendRecord* tcp_get_send_zerocopy_record(
grpc_tcp* /*tcp*/, grpc_slice_buffer* /*buf*/) {
return nullptr;
}
static void ZerocopyDisableAndWaitForRemaining(grpc_tcp* /*tcp*/) {}
static bool tcp_write_with_timestamps(grpc_tcp* /*tcp*/, struct msghdr* /*msg*/,
size_t /*sending_length*/,
ssize_t* /*sent_length*/,
int* /* saved_errno */,
int /*additional_flags*/) {
gpr_log(GPR_ERROR, "Write with timestamps not supported for this platform");
GPR_ASSERT(0);
return false;
}
static void tcp_handle_error(void* /*arg*/ /* grpc_tcp */,
grpc_error_handle /*error*/) {
gpr_log(GPR_ERROR, "Error handling is not supported for this platform");
GPR_ASSERT(0);
}
#endif // GRPC_LINUX_ERRQUEUE
// If outgoing_buffer_arg is filled, shuts down the list early, so that any
// release operations needed can be performed on the arg
void tcp_shutdown_buffer_list(grpc_tcp* tcp) {
if (tcp->outgoing_buffer_arg) {
tcp->tb_list.Shutdown(tcp->outgoing_buffer_arg,
GRPC_ERROR_CREATE("TracedBuffer list shutdown"));
tcp->outgoing_buffer_arg = nullptr;
}
}
#if defined(IOV_MAX) && IOV_MAX < 260
#define MAX_WRITE_IOVEC IOV_MAX
#else
#define MAX_WRITE_IOVEC 260
#endif
msg_iovlen_type TcpZerocopySendRecord::PopulateIovs(size_t* unwind_slice_idx,
size_t* unwind_byte_idx,
size_t* sending_length,
iovec* iov) {
msg_iovlen_type iov_size;
*unwind_slice_idx = out_offset_.slice_idx;
*unwind_byte_idx = out_offset_.byte_idx;
for (iov_size = 0;
out_offset_.slice_idx != buf_.count && iov_size != MAX_WRITE_IOVEC;
iov_size++) {
iov[iov_size].iov_base =
GRPC_SLICE_START_PTR(buf_.slices[out_offset_.slice_idx]) +
out_offset_.byte_idx;
iov[iov_size].iov_len =
GRPC_SLICE_LENGTH(buf_.slices[out_offset_.slice_idx]) -
out_offset_.byte_idx;
*sending_length += iov[iov_size].iov_len;
++(out_offset_.slice_idx);
out_offset_.byte_idx = 0;
}
GPR_DEBUG_ASSERT(iov_size > 0);
return iov_size;
}
void TcpZerocopySendRecord::UpdateOffsetForBytesSent(size_t sending_length,
size_t actually_sent) {
size_t trailing = sending_length - actually_sent;
while (trailing > 0) {
size_t slice_length;
out_offset_.slice_idx--;
slice_length = GRPC_SLICE_LENGTH(buf_.slices[out_offset_.slice_idx]);
if (slice_length > trailing) {
out_offset_.byte_idx = slice_length - trailing;
break;
} else {
trailing -= slice_length;
}
}
}
// returns true if done, false if pending; if returning true, *error is set
static bool do_tcp_flush_zerocopy(grpc_tcp* tcp, TcpZerocopySendRecord* record,
grpc_error_handle* error) {
msg_iovlen_type iov_size;
ssize_t sent_length = 0;
size_t sending_length;
size_t unwind_slice_idx;
size_t unwind_byte_idx;
bool tried_sending_message;
int saved_errno;
msghdr msg;
// iov consumes a large space. Keep it as the last item on the stack to
// improve locality. After all, we expect only the first elements of it being
// populated in most cases.
iovec iov[MAX_WRITE_IOVEC];
while (true) {
sending_length = 0;
iov_size = record->PopulateIovs(&unwind_slice_idx, &unwind_byte_idx,
&sending_length, iov);
msg.msg_name = nullptr;
msg.msg_namelen = 0;
msg.msg_iov = iov;
msg.msg_iovlen = iov_size;
msg.msg_flags = 0;
tried_sending_message = false;
// Before calling sendmsg (with or without timestamps): we
// take a single ref on the zerocopy send record.
tcp->tcp_zerocopy_send_ctx.NoteSend(record);
saved_errno = 0;
if (tcp->outgoing_buffer_arg != nullptr) {
if (!tcp->ts_capable ||
!tcp_write_with_timestamps(tcp, &msg, sending_length, &sent_length,
&saved_errno, MSG_ZEROCOPY)) {
// We could not set socket options to collect Fathom timestamps.
// Fallback on writing without timestamps.
tcp->ts_capable = false;
tcp_shutdown_buffer_list(tcp);
} else {
tried_sending_message = true;
}
}
if (!tried_sending_message) {
msg.msg_control = nullptr;
msg.msg_controllen = 0;
grpc_core::global_stats().IncrementTcpWriteSize(sending_length);
grpc_core::global_stats().IncrementTcpWriteIovSize(iov_size);
sent_length = tcp_send(tcp->fd, &msg, &saved_errno, MSG_ZEROCOPY);
}
if (tcp->tcp_zerocopy_send_ctx.UpdateZeroCopyOMemStateAfterSend(
saved_errno == ENOBUFS)) {
grpc_fd_set_writable(tcp->em_fd);
}
if (sent_length < 0) {
// If this particular send failed, drop ref taken earlier in this method.
tcp->tcp_zerocopy_send_ctx.UndoSend();
if (saved_errno == EAGAIN || saved_errno == ENOBUFS) {
record->UnwindIfThrottled(unwind_slice_idx, unwind_byte_idx);
return false;
} else if (saved_errno == EPIPE) {
*error = tcp_annotate_error(GRPC_OS_ERROR(saved_errno, "sendmsg"), tcp);
tcp_shutdown_buffer_list(tcp);
return true;
} else {
*error = tcp_annotate_error(GRPC_OS_ERROR(saved_errno, "sendmsg"), tcp);
tcp_shutdown_buffer_list(tcp);
return true;
}
}
grpc_core::EventLog::Append("tcp-write-outstanding", -sent_length);
tcp->bytes_counter += sent_length;
record->UpdateOffsetForBytesSent(sending_length,
static_cast<size_t>(sent_length));
if (record->AllSlicesSent()) {
*error = absl::OkStatus();
return true;
}
}
}
static void UnrefMaybePutZerocopySendRecord(grpc_tcp* tcp,
TcpZerocopySendRecord* record,
uint32_t /*seq*/,
const char* /*tag*/) {
if (record->Unref()) {
tcp->tcp_zerocopy_send_ctx.PutSendRecord(record);
}
}
static bool tcp_flush_zerocopy(grpc_tcp* tcp, TcpZerocopySendRecord* record,
grpc_error_handle* error) {
bool done = do_tcp_flush_zerocopy(tcp, record, error);
if (done) {
// Either we encountered an error, or we successfully sent all the bytes.
// In either case, we're done with this record.
UnrefMaybePutZerocopySendRecord(tcp, record, 0, "flush_done");
}
return done;
}
static bool tcp_flush(grpc_tcp* tcp, grpc_error_handle* error) {
struct msghdr msg;
struct iovec iov[MAX_WRITE_IOVEC];
msg_iovlen_type iov_size;
ssize_t sent_length = 0;
size_t sending_length;
size_t trailing;
size_t unwind_slice_idx;
size_t unwind_byte_idx;
int saved_errno;
// We always start at zero, because we eagerly unref and trim the slice
// buffer as we write
size_t outgoing_slice_idx = 0;
while (true) {
sending_length = 0;
unwind_slice_idx = outgoing_slice_idx;
unwind_byte_idx = tcp->outgoing_byte_idx;
for (iov_size = 0; outgoing_slice_idx != tcp->outgoing_buffer->count &&
iov_size != MAX_WRITE_IOVEC;
iov_size++) {
iov[iov_size].iov_base =
GRPC_SLICE_START_PTR(
tcp->outgoing_buffer->slices[outgoing_slice_idx]) +
tcp->outgoing_byte_idx;
iov[iov_size].iov_len =
GRPC_SLICE_LENGTH(tcp->outgoing_buffer->slices[outgoing_slice_idx]) -
tcp->outgoing_byte_idx;
sending_length += iov[iov_size].iov_len;
outgoing_slice_idx++;
tcp->outgoing_byte_idx = 0;
}
GPR_ASSERT(iov_size > 0);
msg.msg_name = nullptr;
msg.msg_namelen = 0;
msg.msg_iov = iov;
msg.msg_iovlen = iov_size;
msg.msg_flags = 0;
bool tried_sending_message = false;
saved_errno = 0;
if (tcp->outgoing_buffer_arg != nullptr) {
if (!tcp->ts_capable ||
!tcp_write_with_timestamps(tcp, &msg, sending_length, &sent_length,
&saved_errno)) {
// We could not set socket options to collect Fathom timestamps.
// Fallback on writing without timestamps.
tcp->ts_capable = false;
tcp_shutdown_buffer_list(tcp);
} else {
tried_sending_message = true;
}
}
if (!tried_sending_message) {
msg.msg_control = nullptr;
msg.msg_controllen = 0;
grpc_core::global_stats().IncrementTcpWriteSize(sending_length);
grpc_core::global_stats().IncrementTcpWriteIovSize(iov_size);
sent_length = tcp_send(tcp->fd, &msg, &saved_errno);
}
if (sent_length < 0) {
if (saved_errno == EAGAIN || saved_errno == ENOBUFS) {
tcp->outgoing_byte_idx = unwind_byte_idx;
// unref all and forget about all slices that have been written to this
// point
for (size_t idx = 0; idx < unwind_slice_idx; ++idx) {
grpc_slice_buffer_remove_first(tcp->outgoing_buffer);
}
return false;
} else if (saved_errno == EPIPE) {
*error = tcp_annotate_error(GRPC_OS_ERROR(saved_errno, "sendmsg"), tcp);
grpc_slice_buffer_reset_and_unref(tcp->outgoing_buffer);
tcp_shutdown_buffer_list(tcp);
return true;
} else {
*error = tcp_annotate_error(GRPC_OS_ERROR(saved_errno, "sendmsg"), tcp);
grpc_slice_buffer_reset_and_unref(tcp->outgoing_buffer);
tcp_shutdown_buffer_list(tcp);
return true;
}
}
GPR_ASSERT(tcp->outgoing_byte_idx == 0);
grpc_core::EventLog::Append("tcp-write-outstanding", -sent_length);
tcp->bytes_counter += sent_length;
trailing = sending_length - static_cast<size_t>(sent_length);
while (trailing > 0) {
size_t slice_length;
outgoing_slice_idx--;
slice_length =
GRPC_SLICE_LENGTH(tcp->outgoing_buffer->slices[outgoing_slice_idx]);
if (slice_length > trailing) {
tcp->outgoing_byte_idx = slice_length - trailing;
break;
} else {
trailing -= slice_length;
}
}
if (outgoing_slice_idx == tcp->outgoing_buffer->count) {
*error = absl::OkStatus();
grpc_slice_buffer_reset_and_unref(tcp->outgoing_buffer);
return true;
}
}
}
static void tcp_handle_write(void* arg /* grpc_tcp */,
grpc_error_handle error) {
grpc_tcp* tcp = static_cast<grpc_tcp*>(arg);
grpc_closure* cb;
if (!error.ok()) {
cb = tcp->write_cb;
tcp->write_cb = nullptr;
if (tcp->current_zerocopy_send != nullptr) {
UnrefMaybePutZerocopySendRecord(tcp, tcp->current_zerocopy_send, 0,
"handle_write_err");
tcp->current_zerocopy_send = nullptr;
}
grpc_core::Closure::Run(DEBUG_LOCATION, cb, error);
TCP_UNREF(tcp, "write");
return;
}
bool flush_result =
tcp->current_zerocopy_send != nullptr
? tcp_flush_zerocopy(tcp, tcp->current_zerocopy_send, &error)
: tcp_flush(tcp, &error);
if (!flush_result) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "write: delayed");
}
notify_on_write(tcp);
// tcp_flush does not populate error if it has returned false.
GPR_DEBUG_ASSERT(error.ok());
} else {
cb = tcp->write_cb;
tcp->write_cb = nullptr;
tcp->current_zerocopy_send = nullptr;
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "write: %s", grpc_core::StatusToString(error).c_str());
}
// No need to take a ref on error since tcp_flush provides a ref.
grpc_core::Closure::Run(DEBUG_LOCATION, cb, error);
TCP_UNREF(tcp, "write");
}
}
static void tcp_write(grpc_endpoint* ep, grpc_slice_buffer* buf,
grpc_closure* cb, void* arg, int /*max_frame_size*/) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
grpc_error_handle error;
TcpZerocopySendRecord* zerocopy_send_record = nullptr;
grpc_core::EventLog::Append("tcp-write-outstanding", buf->length);
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
size_t i;
for (i = 0; i < buf->count; i++) {
gpr_log(GPR_INFO, "WRITE %p (peer=%s)", tcp, tcp->peer_string.c_str());
if (gpr_should_log(GPR_LOG_SEVERITY_DEBUG)) {
char* data =
grpc_dump_slice(buf->slices[i], GPR_DUMP_HEX | GPR_DUMP_ASCII);
gpr_log(GPR_DEBUG, "WRITE DATA: %s", data);
gpr_free(data);
}
}
}
GPR_ASSERT(tcp->write_cb == nullptr);
GPR_DEBUG_ASSERT(tcp->current_zerocopy_send == nullptr);
if (buf->length == 0) {
grpc_core::Closure::Run(
DEBUG_LOCATION, cb,
grpc_fd_is_shutdown(tcp->em_fd)
? tcp_annotate_error(GRPC_ERROR_CREATE("EOF"), tcp)
: absl::OkStatus());
tcp_shutdown_buffer_list(tcp);
return;
}
zerocopy_send_record = tcp_get_send_zerocopy_record(tcp, buf);
if (zerocopy_send_record == nullptr) {
// Either not enough bytes, or couldn't allocate a zerocopy context.
tcp->outgoing_buffer = buf;
tcp->outgoing_byte_idx = 0;
}
tcp->outgoing_buffer_arg = arg;
if (arg) {
GPR_ASSERT(grpc_event_engine_can_track_errors());
}
bool flush_result =
zerocopy_send_record != nullptr
? tcp_flush_zerocopy(tcp, zerocopy_send_record, &error)
: tcp_flush(tcp, &error);
if (!flush_result) {
TCP_REF(tcp, "write");
tcp->write_cb = cb;
tcp->current_zerocopy_send = zerocopy_send_record;
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "write: delayed");
}
notify_on_write(tcp);
} else {
if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
gpr_log(GPR_INFO, "write: %s", grpc_core::StatusToString(error).c_str());
}
grpc_core::Closure::Run(DEBUG_LOCATION, cb, error);
}
}
static void tcp_add_to_pollset(grpc_endpoint* ep, grpc_pollset* pollset) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
grpc_pollset_add_fd(pollset, tcp->em_fd);
}
static void tcp_add_to_pollset_set(grpc_endpoint* ep,
grpc_pollset_set* pollset_set) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
grpc_pollset_set_add_fd(pollset_set, tcp->em_fd);
}
static void tcp_delete_from_pollset_set(grpc_endpoint* ep,
grpc_pollset_set* pollset_set) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
grpc_pollset_set_del_fd(pollset_set, tcp->em_fd);
}
static absl::string_view tcp_get_peer(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
return tcp->peer_string;
}
static absl::string_view tcp_get_local_address(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
return tcp->local_address;
}
static int tcp_get_fd(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
return tcp->fd;
}
static bool tcp_can_track_err(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
if (!grpc_event_engine_can_track_errors()) {
return false;
}
struct sockaddr addr;
socklen_t len = sizeof(addr);
if (getsockname(tcp->fd, &addr, &len) < 0) {
return false;
}
return addr.sa_family == AF_INET || addr.sa_family == AF_INET6;
}
static const grpc_endpoint_vtable vtable = {tcp_read,
tcp_write,
tcp_add_to_pollset,
tcp_add_to_pollset_set,
tcp_delete_from_pollset_set,
tcp_shutdown,
tcp_destroy,
tcp_get_peer,
tcp_get_local_address,
tcp_get_fd,
tcp_can_track_err};
grpc_endpoint* grpc_tcp_create(grpc_fd* em_fd,
const grpc_core::PosixTcpOptions& options,
absl::string_view peer_string) {
grpc_tcp* tcp = new grpc_tcp(options);
tcp->base.vtable = &vtable;
tcp->peer_string = std::string(peer_string);
tcp->fd = grpc_fd_wrapped_fd(em_fd);
GPR_ASSERT(options.resource_quota != nullptr);
tcp->memory_owner =
options.resource_quota->memory_quota()->CreateMemoryOwner(peer_string);
tcp->self_reservation = tcp->memory_owner.MakeReservation(sizeof(grpc_tcp));
grpc_resolved_address resolved_local_addr;
memset(&resolved_local_addr, 0, sizeof(resolved_local_addr));
resolved_local_addr.len = sizeof(resolved_local_addr.addr);
absl::StatusOr<std::string> addr_uri;
if (getsockname(tcp->fd,
reinterpret_cast<sockaddr*>(resolved_local_addr.addr),
&resolved_local_addr.len) < 0 ||
!(addr_uri = grpc_sockaddr_to_uri(&resolved_local_addr)).ok()) {
tcp->local_address = "";
} else {
tcp->local_address = addr_uri.value();
}
tcp->read_cb = nullptr;
tcp->write_cb = nullptr;
tcp->current_zerocopy_send = nullptr;
tcp->release_fd_cb = nullptr;
tcp->release_fd = nullptr;
tcp->target_length = static_cast<double>(options.tcp_read_chunk_size);
tcp->bytes_read_this_round = 0;
// Will be set to false by the very first endpoint read function
tcp->is_first_read = true;
tcp->bytes_counter = -1;
tcp->socket_ts_enabled = false;
tcp->ts_capable = true;
tcp->outgoing_buffer_arg = nullptr;
tcp->min_progress_size = 1;
if (options.tcp_tx_zero_copy_enabled &&
!tcp->tcp_zerocopy_send_ctx.memory_limited()) {
#ifdef GRPC_LINUX_ERRQUEUE
const int enable = 1;
auto err =
setsockopt(tcp->fd, SOL_SOCKET, SO_ZEROCOPY, &enable, sizeof(enable));
if (err == 0) {
tcp->tcp_zerocopy_send_ctx.set_enabled(true);
} else {
gpr_log(GPR_ERROR, "Failed to set zerocopy options on the socket.");
}
#endif
}
// paired with unref in grpc_tcp_destroy
new (&tcp->refcount) grpc_core::RefCount(
1, GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace) ? "tcp" : nullptr);
gpr_atm_no_barrier_store(&tcp->shutdown_count, 0);
tcp->em_fd = em_fd;
grpc_slice_buffer_init(&tcp->last_read_buffer);
GRPC_CLOSURE_INIT(&tcp->read_done_closure, tcp_handle_read, tcp,
grpc_schedule_on_exec_ctx);
if (grpc_event_engine_run_in_background()) {
// If there is a polling engine always running in the background, there is
// no need to run the backup poller.
GRPC_CLOSURE_INIT(&tcp->write_done_closure, tcp_handle_write, tcp,
grpc_schedule_on_exec_ctx);
} else {
GRPC_CLOSURE_INIT(&tcp->write_done_closure,
tcp_drop_uncovered_then_handle_write, tcp,
grpc_schedule_on_exec_ctx);
}
// Always assume there is something on the queue to read.
tcp->inq = 1;
#ifdef GRPC_HAVE_TCP_INQ
int one = 1;
if (setsockopt(tcp->fd, SOL_TCP, TCP_INQ, &one, sizeof(one)) == 0) {
tcp->inq_capable = true;
} else {
gpr_log(GPR_DEBUG, "cannot set inq fd=%d errno=%d", tcp->fd, errno);
tcp->inq_capable = false;
}
#else
tcp->inq_capable = false;
#endif // GRPC_HAVE_TCP_INQ
// Start being notified on errors if event engine can track errors.
if (grpc_event_engine_can_track_errors()) {
// Grab a ref to tcp so that we can safely access the tcp struct when
// processing errors. We unref when we no longer want to track errors
// separately.
TCP_REF(tcp, "error-tracking");
gpr_atm_rel_store(&tcp->stop_error_notification, 0);
GRPC_CLOSURE_INIT(&tcp->error_closure, tcp_handle_error, tcp,
grpc_schedule_on_exec_ctx);
grpc_fd_notify_on_error(tcp->em_fd, &tcp->error_closure);
}
return &tcp->base;
}
int grpc_tcp_fd(grpc_endpoint* ep) {
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
GPR_ASSERT(ep->vtable == &vtable);
return grpc_fd_wrapped_fd(tcp->em_fd);
}
void grpc_tcp_destroy_and_release_fd(grpc_endpoint* ep, int* fd,
grpc_closure* done) {
if (grpc_event_engine::experimental::grpc_is_event_engine_endpoint(ep)) {
return grpc_event_engine::experimental::
grpc_event_engine_endpoint_destroy_and_release_fd(ep, fd, done);
}
grpc_tcp* tcp = reinterpret_cast<grpc_tcp*>(ep);
GPR_ASSERT(ep->vtable == &vtable);
tcp->release_fd = fd;
tcp->release_fd_cb = done;
grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
if (grpc_event_engine_can_track_errors()) {
// Stop errors notification.
ZerocopyDisableAndWaitForRemaining(tcp);
gpr_atm_no_barrier_store(&tcp->stop_error_notification, true);
grpc_fd_set_error(tcp->em_fd);
}
tcp->read_mu.Lock();
tcp->memory_owner.Reset();
tcp->read_mu.Unlock();
TCP_UNREF(tcp, "destroy");
}
void grpc_tcp_posix_init() { g_backup_poller_mu = new grpc_core::Mutex; }
void grpc_tcp_posix_shutdown() {
delete g_backup_poller_mu;
g_backup_poller_mu = nullptr;
}
#endif // GRPC_POSIX_SOCKET_TCP