Create an experiment to study whether too many bindings cause NAT failure

content/renderer/media/webrtc/stun_field_trial.cc

Index: content/renderer/media/webrtc/stun_field_trial.cc
diff --git a/content/renderer/media/webrtc/stun_field_trial.cc b/content/renderer/media/webrtc/stun_field_trial.cc
index 41be3588a749b09ce5071862cd892effe1095dca..98761af520b3094c086d4e189783be6987bf0659 100644
--- a/content/renderer/media/webrtc/stun_field_trial.cc
+++ b/content/renderer/media/webrtc/stun_field_trial.cc
@@ -6,8 +6,10 @@
 
 #include <math.h>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
@@ -21,7 +23,6 @@
 #include "third_party/webrtc/base/socketaddress.h"
 #include "third_party/webrtc/base/thread.h"
 #include "third_party/webrtc/p2p/base/packetsocketfactory.h"
-#include "third_party/webrtc/p2p/stunprober/stunprober.h"
 
 using stunprober::StunProber;
 
@@ -65,78 +66,145 @@ int ClampProbingInterval(int interval_ms) {
 
 std::string HistogramName(const std::string& prefix,
                           NatType nat_type,
-                          int interval_ms) {
-  return base::StringPrintf("WebRTC.Stun.%s.%s.%dms", prefix.c_str(),
-                            NatTypeNames[nat_type], interval_ms);
+                          int interval_ms,
+                          int batch_index) {
+  return base::StringPrintf("WebRTC.Stun.%s.%s.%dms.%d.%d", prefix.c_str(),
+                            NatTypeNames[nat_type], interval_ms, batch_index);
 }
 
-void SaveHistogramData(StunProber* prober) {
-  StunProber::Stats stats;
-  if (!prober->GetStats(&stats))
-    return;
-
-  NatType nat_type = GetNatType(stats.nat_type);
-
-  // Use the real probe interval for reporting, converting from nanosecond to
-  // millisecond at 5ms boundary.
-  int interval_ms =
-      round(static_cast<float>(stats.actual_request_interval_ns) / 5000) * 5;
-
-  interval_ms = ClampProbingInterval(interval_ms);
-
-  UMA_HISTOGRAM_ENUMERATION("WebRTC.NAT.Metrics", nat_type, NAT_TYPE_MAX);
-
-  std::string histogram_name =
-      HistogramName("SuccessPercent", nat_type, interval_ms);
-
-  // Mimic the same behavior as UMA_HISTOGRAM_PERCENTAGE. We can't use that
-  // macro as the histogram name is determined dynamically.
-  base::HistogramBase* histogram = base::Histogram::FactoryGet(
-      histogram_name, 1, 101, 102, base::Histogram::kUmaTargetedHistogramFlag);
-  histogram->Add(stats.success_percent);
+}  // namespace
 
-  DVLOG(1) << "Histogram '" << histogram_name.c_str()
-           << "' = " << stats.success_percent;
+StunProberWithWeakPtr::StunProberWithWeakPtr(StunProber* prober)
+    : prober_(prober), weak_factory_(this) {}
 
-  histogram_name = HistogramName("ResponseLatency", nat_type, interval_ms);
+void StunProberWithWeakPtr::set_next_prober(
+    StunProberWithWeakPtr* next_prober) {
+  DCHECK(!next_prober_);
+  next_prober_ = next_prober;
+}
 
-  histogram = base::Histogram::FactoryTimeGet(
-      histogram_name, base::TimeDelta::FromMilliseconds(1),
-      base::TimeDelta::FromSeconds(10), 50,
-      base::Histogram::kUmaTargetedHistogramFlag);
-  histogram->AddTime(base::TimeDelta::FromMilliseconds(stats.average_rtt_ms));
+void StunProberWithWeakPtr::Start(StunProber::Observer* observer) {
+  if (next_prober_) {
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE, base::Bind(&StunProberWithWeakPtr::Start,
+                              next_prober_->GetWeakPtr(), observer),
+        base::TimeDelta::FromMilliseconds(prober_->estimated_execution_time()));
+  }
+  prober_->Start(observer);
+}
 
-  DVLOG(1) << "Histogram '" << histogram_name.c_str()
-           << "' = " << stats.average_rtt_ms << " ms";
+StunProberWithWeakPtr::~StunProberWithWeakPtr() {
+  if (next_prober_) {
+    base::MessageLoop::current()->DeleteSoon(FROM_HERE, next_prober_);
+  }
+}
 
-  DVLOG(1) << "Shared Socket Mode: " << stats.shared_socket_mode;
-  DVLOG(1) << "Requests sent: " << stats.num_request_sent;
-  DVLOG(1) << "Responses received: " << stats.num_response_received;
-  DVLOG(1) << "Target interval (ns): " << stats.target_request_interval_ns;
-  DVLOG(1) << "Actual interval (ns): " << stats.actual_request_interval_ns;
-  DVLOG(1) << "NAT Type: " << NatTypeNames[nat_type];
-  DVLOG(1) << "Host IP: " << stats.host_ip;
-  DVLOG(1) << "Server-reflexive ips: ";
-  for (const auto& ip : stats.srflx_addrs)
-    DVLOG(1) << "\t" << ip;
+StunProberTrial::StunProberTrial(rtc::NetworkManager* network_manager,
+                                 const std::string& params,
+                                 rtc::PacketSocketFactory* factory)
+    : network_manager_(network_manager), params_(params), factory_(factory) {
+  // We have to connect to the signal to avoid a race condition if network
+  // manager hasn't received the network update when we start, the StunProber
+  // will just fail.
+  network_manager_->SignalNetworksChanged.connect(
+      this, &StunProberTrial::OnNetworksChanged);
+  network_manager_->StartUpdating();
 }
 
-void OnStunProbeTrialFinished(StunProber* prober, int result) {
-  if (result == StunProber::SUCCESS)
-    SaveHistogramData(prober);
+StunProberTrial::~StunProberTrial() {
+  DCHECK(thread_checker_.CalledOnValidThread());
 }
 
-}  // namespace
+void StunProberTrial::SaveHistogramData() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  NatType nat_type = NAT_TYPE_MAX;
+  int interval_ms = 0;
+  int count = 0;
+  int total_sent = 0;
+  int total_recv = 0;
+  for (StunProberWithWeakPtr* prober = prober_head_.get(); prober != nullptr;
+       prober = prober->GetNextProber()) {
+    ++count;
+
+    // Get the stats.
+    StunProber::Stats stats;
+    if (!prober->GetStats(&stats))
+      return;
+
+    // Check if the NAT type is consistent.
+    if (nat_type == NAT_TYPE_MAX) {
+      nat_type = GetNatType(stats.nat_type);
+      // If we can't figure out the nattype at the beginning, just return.
+      if (nat_type == NAT_TYPE_UNKNOWN)
+        return;
+    }
+    // For subsequent probers, we might get unknown as nattype if all the
+    // bindings fail, but it's ok.
+    else if (nat_type != GetNatType(stats.nat_type) &&
+             nat_type != NAT_TYPE_UNKNOWN)
+      return;
+
+    // Check that the interval is consistent.
+    // Use the real probe interval for reporting, converting from nanosecond to
+    // millisecond at 5ms boundary.
+    int new_interval_ms = ClampProbingInterval(
+        round(static_cast<float>(stats.actual_request_interval_ns) / 5000) * 5);
+    if (interval_ms == 0) {
+      interval_ms = new_interval_ms;
+    } else if (interval_ms != new_interval_ms)
+      return;
+
+    // Sum up the total sent and recv packets.
+    total_sent += stats.num_request_sent;
+    total_recv += stats.num_response_received;
+
+    if (count % batch_size_ > 0)
+      continue;
+
+    if (total_sent == 0) {
+      total_recv = 0;
+      continue;
+    }
+
+    int success_rate = total_recv * 100 / total_sent;
+    std::string histogram_name = HistogramName(
+        "SuccessPercent", nat_type, interval_ms, count / batch_size_);
+
+    // Mimic the same behavior as UMA_HISTOGRAM_PERCENTAGE. We can't use
+    // that macro as the histogram name is determined dynamically.
+    base::HistogramBase* histogram =
+        base::Histogram::FactoryGet(histogram_name, 1, 101, 102,
+                                    base::Histogram::kUmaTargetedHistogramFlag);
+    histogram->Add(success_rate);
+
+    DVLOG(1) << "Histogram '" << histogram_name.c_str()
+             << "' = " << stats.success_percent;
+
+    DVLOG(1) << "Shared Socket Mode: " << stats.shared_socket_mode;
+    DVLOG(1) << "Requests sent: " << total_sent;
+    DVLOG(1) << "Responses received: " << total_recv;
+    DVLOG(1) << "Target interval (ns): " << stats.target_request_interval_ns;
+    DVLOG(1) << "Actual interval (ns): " << stats.actual_request_interval_ns;
+    DVLOG(1) << "NAT Type: " << NatTypeNames[nat_type];
+    DVLOG(1) << "Host IP: " << stats.host_ip;
+
+    total_sent = 0;
+    total_recv = 0;
+  }
+}
 
-bool ParseStunProbeParameters(const std::string& params,
-                              int* requests_per_ip,
-                              int* interval_ms,
-                              int* shared_socket_mode,
-                              std::vector<rtc::SocketAddress>* servers) {
+bool StunProberTrial::ParseParameters(
+    const std::string& params,
+    int* requests_per_ip,
+    int* interval_ms,
+    int* shared_socket_mode,
+    int* batch_size,
+    int* total_batches,
+    std::vector<rtc::SocketAddress>* servers) {
   std::vector<std::string> stun_params = base::SplitString(
       params, "/", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
 
-  if (stun_params.size() < 4) {
+  if (stun_params.size() < 5) {
     DLOG(ERROR) << "Not enough parameters specified in StartStunProbeTrial";
     return false;
   }
@@ -168,6 +236,22 @@ bool ParseStunProbeParameters(const std::string& params,
   }
   param++;
 
+  if (param->empty()) {
+    *batch_size = 5;
+  } else if (!base::StringToInt(*param, batch_size)) {
+    DLOG(ERROR) << "Failed to parse batch_size in StartStunProbeTrial";
+    return false;
+  }
+  param++;
+
+  if (param->empty()) {
+    *total_batches = 5;
+  } else if (!base::StringToInt(*param, total_batches)) {
+    DLOG(ERROR) << "Failed to parse total_batches in StartStunProbeTrial";
+    return false;
+  }
+  param++;
+
   while (param != stun_params.end() && !param->empty()) {
     rtc::SocketAddress server;
     if (!server.FromString(*param)) {
@@ -181,42 +265,77 @@ bool ParseStunProbeParameters(const std::string& params,
   return !servers->empty();
 }
 
-scoped_ptr<stunprober::StunProber> StartStunProbeTrial(
-    const rtc::NetworkManager::NetworkList& networks,
-    const std::string& params,
-    rtc::PacketSocketFactory* factory) {
-  DVLOG(1) << "Starting stun trial with params: " << params;
+void StunProberTrial::OnNetworksChanged() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DVLOG(1) << "Starting stun trial with params: " << params_;
+  rtc::NetworkManager::NetworkList networks;
+  network_manager_->GetNetworks(&networks);
 
   // If we don't have local addresses, we won't be able to determine whether
   // we're behind NAT or not.
   if (networks.empty()) {
     DLOG(ERROR) << "No networks specified in StartStunProbeTrial";
-    return nullptr;
+    return;
   }
 
+  network_manager_->StopUpdating();
+  network_manager_->SignalNetworksChanged.disconnect(this);
+
   int requests_per_ip;
-  int interval_ms;
   int shared_socket_mode;
+  int interval_ms;
+  int total_batches;
   std::vector<rtc::SocketAddress> servers;
 
-  if (!ParseStunProbeParameters(params, &requests_per_ip, &interval_ms,
-                                &shared_socket_mode, &servers)) {
-    return nullptr;
+  if (!ParseParameters(params_, &requests_per_ip, &interval_ms,
+                       &shared_socket_mode, &batch_size_, &total_batches,
+                       &servers)) {
+    return;
   }
 
-  scoped_ptr<StunProber> prober(
-      new StunProber(factory, rtc::Thread::Current(), networks));
+  total_probers_ = total_batches * batch_size_;
+
+  StunProberWithWeakPtr* prev_prober = nullptr;
+
+  for (int i = 0; i < total_probers_; i++) {
+    stunprober::StunProber* prober =
+        new StunProber(factory_, rtc::Thread::Current(), networks);
+    scoped_ptr<StunProberWithWeakPtr> prober_wp(
+        new StunProberWithWeakPtr(prober));
+    if (!prober->Prepare(servers, (shared_socket_mode != 0), interval_ms,
+                         requests_per_ip, 1000, this)) {
+      DLOG(ERROR) << "Failed to Prepare in StartStunProbeTrial";
+      return;
+    }
+
+    if (prev_prober)
+      prev_prober->set_next_prober(prober_wp.get());
+    else
+      prober_head_.reset(prober_wp.get());
 
-  if (!prober->Start(
-          servers, (shared_socket_mode != 0), interval_ms, requests_per_ip,
-          1000,
-          rtc::Callback2<void, StunProber*, int>(&OnStunProbeTrialFinished))) {
-    DLOG(ERROR) << "Failed to Start in StartStunProbeTrial";
-    OnStunProbeTrialFinished(prober.get(), StunProber::GENERIC_FAILURE);
-    return nullptr;
+    prev_prober = prober_wp.release();
   }
+}
 
-  return prober;
+void StunProberTrial::OnFinished(StunProber* prober,
+                                 StunProber::Status result) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (result == StunProber::SUCCESS)
+    ++finished_probers_;
+
+  if (finished_probers_ == total_probers_)
+    SaveHistogramData();
 }
 
+void StunProberTrial::OnPrepared(StunProber* prober,
+                                 StunProber::Status result) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (result == StunProber::SUCCESS)
+    ++ready_probers_;
+
+  if (ready_probers_ == total_probers_) {
+    DCHECK(prober_head_);
+    prober_head_->Start(this);
+  }
+}
 }  // namespace content