Merge QUIC StrikeRegister code to chromium.

net/quic/crypto/strike_register_test.cc

Index: net/quic/crypto/strike_register_test.cc
diff --git a/net/quic/crypto/strike_register_test.cc b/net/quic/crypto/strike_register_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4dd479ea0eb0e365c752c65e92ecc43f1bc02a72
--- /dev/null
+++ b/net/quic/crypto/strike_register_test.cc
@@ -0,0 +1,271 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/quic/crypto/strike_register.h"
+
+#include <set>
+#include <string>
+
+#include "base/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+using net::StrikeRegister;
+using std::set;
+using std::string;
+
+const uint8 kOrbit[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+void
+NonceSetTimeAndOrbit(uint8 nonce[32], unsigned time, const uint8 orbit[8]) {
+  nonce[0] = time >> 24;
+  nonce[1] = time >> 16;
+  nonce[2] = time >> 8;
+  nonce[3] = time;
+  memcpy(nonce + 4, orbit, 8);
+}
+
+TEST(StrikeRegisterTest, SimpleHorizon) {
+  // The set must reject values created on or before its own creation time.
+  StrikeRegister set(10 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[32];
+  NonceSetTimeAndOrbit(nonce, 999, kOrbit);
+  ASSERT_FALSE(set.Insert(nonce, 1000));
+  NonceSetTimeAndOrbit(nonce, 1000, kOrbit);
+  ASSERT_FALSE(set.Insert(nonce, 1000));
+}
+
+TEST(StrikeRegisterTest, WindowFuture) {
+  // The set must reject values outside the window.
+  StrikeRegister set(10 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[32];
+  NonceSetTimeAndOrbit(nonce, 1101, kOrbit);
+  ASSERT_FALSE(set.Insert(nonce, 1000));
+  NonceSetTimeAndOrbit(nonce, 999, kOrbit);
+  ASSERT_FALSE(set.Insert(nonce, 1100));
+}
+
+TEST(StrikeRegisterTest, BadOrbit) {
+  // The set must reject values with the wrong orbit
+  StrikeRegister set(10 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[32];
+  static const uint8 kBadOrbit[8] = {0, 0, 0, 0, 1, 1, 1, 1};
+  NonceSetTimeAndOrbit(nonce, 1101, kBadOrbit);
+  ASSERT_FALSE(set.Insert(nonce, 1100));
+}
+
+TEST(StrikeRegisterTest, OneValue) {
+  StrikeRegister set(10 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[32];
+  NonceSetTimeAndOrbit(nonce, 1101, kOrbit);
+  ASSERT_TRUE(set.Insert(nonce, 1100));
+}
+
+TEST(StrikeRegisterTest, RejectDuplicate) {
+  // The set must reject values with the wrong orbit
+  StrikeRegister set(10 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[32];
+  memset(nonce, 0, sizeof(nonce));
+  NonceSetTimeAndOrbit(nonce, 1101, kOrbit);
+  ASSERT_TRUE(set.Insert(nonce, 1100));
+  ASSERT_FALSE(set.Insert(nonce, 1100));
+}
+
+TEST(StrikeRegisterTest, HorizonUpdating) {
+  StrikeRegister set(5 /* max size */, 1000 /* current time */,
+                     100 /* window secs */, kOrbit);
+  uint8 nonce[6][32];
+  for (unsigned i = 0; i < 5; i++) {
+    NonceSetTimeAndOrbit(nonce[i], 1101, kOrbit);
+    memset(nonce[i] + 12, 0, 20);
+    nonce[i][31] = i;
+    ASSERT_TRUE(set.Insert(nonce[i], 1100));
+  }
+
+  // This should push the oldest value out and force the horizon to be updated.
+  NonceSetTimeAndOrbit(nonce[5], 1102, kOrbit);
+  memset(nonce[5] + 12, 0, 20);
+  ASSERT_TRUE(set.Insert(nonce[5], 1100));
+
+  // This should be behind the horizon now:
+  NonceSetTimeAndOrbit(nonce[5], 1101, kOrbit);
+  memset(nonce[5] + 12, 0, 20);
+  nonce[5][31] = 10;
+  ASSERT_FALSE(set.Insert(nonce[5], 1100));
+}
+
+TEST(StrikeRegisterTest, InsertMany) {
+  StrikeRegister set(5000 /* max size */, 1000 /* current time */,
+                     500 /* window secs */, kOrbit);
+
+  uint8 nonce[32];
+  NonceSetTimeAndOrbit(nonce, 1101, kOrbit);
+  for (unsigned i = 0; i < 100000; i++) {
+    NonceSetTimeAndOrbit(nonce, 1101 + i/500, kOrbit);
+    memcpy(nonce + 12, &i, sizeof(i));
+    set.Insert(nonce, 1100);
+  }
+}
+
+
+// For the following test we create a slow, but simple, version of a
+// StrikeRegister. The behaviour of this object is much easier to understand
+// than the fully fledged version. We then create a test to show, empirically,
+// that the two objects have identical behaviour.
+
+// A SlowStrikeRegister has the same public interface as a StrikeRegister, but
+// is much slower. Hopefully it is also more obviously correct and we can
+// empirically test that their behaviours are identical.
+class SlowStrikeRegister {
+ public:
+  SlowStrikeRegister(unsigned max_entries, uint32 current_time,
+                     uint32 window_secs, const uint8 orbit[8])
+      : max_entries_(max_entries),
+        window_secs_(window_secs),
+        horizon_(current_time + window_secs) {
+    memcpy(orbit_, orbit, sizeof(orbit_));
+  }
+
+  bool Insert(const uint8 nonce_bytes[32], const uint32 current_time) {
+    // Same overflow and underflow check as the real StrikeRegister.
+    if (current_time < window_secs_ ||
+        current_time + window_secs_ < current_time) {
+      nonces_.clear();
+      horizon_ = current_time;
+      return false;
+    }
+
+    // Check to see if the orbit is correct.
+    if (memcmp(nonce_bytes + 4, orbit_, sizeof(orbit_))) {
+      return false;
+    }
+    const uint32 nonce_time = TimeFromBytes(nonce_bytes);
+    // We have dropped one or more nonces with a time value of |horizon_|, so
+    // we have to reject anything with a timestamp less than or equal to that.
+    if (nonce_time <= horizon_) {
+      return false;
+    }
+
+    // Check that the timestamp is in the current window.
+    if (nonce_time < (current_time - window_secs_) ||
+        nonce_time > (current_time + window_secs_)) {
+      return false;
+    }
+
+    const string nonce(reinterpret_cast<const char*>(nonce_bytes), 32);
+
+    set<string>::const_iterator it = nonces_.find(nonce);
+    if (it != nonces_.end()) {
+      return false;
+    }
+
+    if (nonces_.size() == max_entries_) {
+      DropOldestEntry();
+    }
+
+    nonces_.insert(nonce);
+    return true;
+  }
+
+ private:
+  // TimeFromBytes returns a big-endian uint32 from |d|.
+  static uint32 TimeFromBytes(const uint8 d[4]) {
+    return static_cast<uint32>(d[0]) << 24 |
+           static_cast<uint32>(d[1]) << 16 |
+           static_cast<uint32>(d[2]) << 8 |
+           static_cast<uint32>(d[3]);
+  }
+
+  void DropOldestEntry() {
+    set<string>::iterator oldest = nonces_.begin(), it;
+    uint32 oldest_time =
+      TimeFromBytes(reinterpret_cast<const uint8*>(oldest->data()));
+
+    for (it = oldest; it != nonces_.end(); it++) {
+      uint32 t = TimeFromBytes(reinterpret_cast<const uint8*>(it->data()));
+      if (t < oldest_time ||
+          (t == oldest_time && memcmp(it->data(), oldest->data(), 32) < 0)) {
+        oldest_time = t;
+        oldest = it;
+      }
+    }
+
+    nonces_.erase(oldest);
+    horizon_ = oldest_time;
+  }
+
+  const unsigned max_entries_;
+  const unsigned window_secs_;
+  uint8 orbit_[8];
+  uint32 horizon_;
+
+  set<string> nonces_;
+};
+
+TEST(StrikeRegisterStressTest, Stress) {
+  // Fixed seed gives reproducibility for this test.
+  srand(42);
+  unsigned max_entries = 64;
+  uint32 current_time = 10000, window = 200;
+  scoped_ptr<StrikeRegister> s1(new StrikeRegister(
+      max_entries, current_time, window, kOrbit));
+  scoped_ptr<SlowStrikeRegister> s2(new SlowStrikeRegister(
+      max_entries, current_time, window, kOrbit));
+  uint64 i;
+
+  // When making changes it's worth removing the limit on this test and running
+  // it for a while. For the initial development an opt binary was left running
+  // for 10 minutes.
+  const uint64 kMaxIterations = 10000;
+  for (i = 0; i < kMaxIterations; i++) {
+    if (rand() % 1000 == 0) {
+      // 0.1% chance of resetting the sets.
+      max_entries = rand() % 300 + 2;
+      current_time = rand() % 10000;
+      window = rand() % 500;
+      s1.reset(new StrikeRegister(max_entries, current_time, window, kOrbit));
+      s2.reset(new SlowStrikeRegister(max_entries, current_time, window,
+                                      kOrbit));
+    }
+
+    int32 time_delta = rand() % (window * 4);
+    time_delta -= window * 2;
+    const uint32 time = current_time + time_delta;
+    if (time_delta < 0 && time > current_time) {
+      continue;  // overflow
+    }
+
+    uint8 nonce[32];
+    NonceSetTimeAndOrbit(nonce, time, kOrbit);
+    memset(nonce + 12, 0, 20);
+
+    // There are 2048 possible nonce values:
+    const uint32 v = rand() % 2048;
+    nonce[30] = v >> 8;
+    nonce[31] = v;
+
+    const bool r2 = s2->Insert(nonce, time);
+    const bool r1 = s1->Insert(nonce, time);
+
+    if (r1 != r2) {
+      break;
+    }
+
+    if (i % 10 == 0) {
+      s1->Validate();
+    }
+  }
+
+  if (i != kMaxIterations) {
+    FAIL() << "Failed after " << i << " iterations";
+  }
+}
+
+}  // anonymous namespace