Make ERR_ICANN_NAME_COLLISION work for async DNS resolver.

net/dns/dns_test_util.cc

 // Copyright (c) 2012 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/dns/dns_test_util.h"
 
 #include <string>
 
 #include "base/big_endian.h"
 #include "base/bind.h"
@@ skipping 39 matching lines @@
         started_(false),
         delayed_(false) {
     // Find the relevant rule which matches |qtype| and prefix of |hostname|.
     for (size_t i = 0; i < rules.size(); ++i) {
       const std::string& prefix = rules[i].prefix;
       if ((rules[i].qtype == qtype) &&
           (hostname.size() >= prefix.size()) &&
           (hostname.compare(0, prefix.size(), prefix) == 0)) {
         result_ = rules[i].result;
         delayed_ = rules[i].delay;
+
+        // Fill in an IP address for the result if one was not specified.
+        if (result_.ip.empty() && result_.type == MockDnsClientRule::OK) {
+          result_.ip = qtype_ == dns_protocol::kTypeA
+                           ? IPAddress::IPv4Localhost()
+                           : IPAddress::IPv6Localhost();
+        }
         break;
       }
     }
   }
 
   const std::string& GetHostname() const override { return hostname_; }
 
   uint16_t GetType() const override { return qtype_; }
 
   void Start() override {
     EXPECT_FALSE(started_);
     started_ = true;
     if (delayed_)
       return;
     // Using WeakPtr to cleanly cancel when transaction is destroyed.
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(&MockTransaction::Finish, AsWeakPtr()));
   }
 
   void FinishDelayedTransaction() {
     EXPECT_TRUE(delayed_);
     delayed_ = false;
     Finish();
   }
 
   bool delayed() const { return delayed_; }
 
  private:
   void Finish() {
-    switch (result_) {
+    switch (result_.type) {
       case MockDnsClientRule::EMPTY:
       case MockDnsClientRule::OK: {
         std::string qname;
         DNSDomainFromDot(hostname_, &qname);
         DnsQuery query(0, qname, qtype_);
 
         DnsResponse response;
         char* buffer = response.io_buffer()->data();
         int nbytes = query.io_buffer()->size();
         memcpy(buffer, query.io_buffer()->data(), nbytes);
         dns_protocol::Header* header =
             reinterpret_cast<dns_protocol::Header*>(buffer);
         header->flags |= dns_protocol::kFlagResponse;
 
-        if (MockDnsClientRule::OK == result_) {
+        if (MockDnsClientRule::OK == result_.type) {
           const uint16_t kPointerToQueryName =
               static_cast<uint16_t>(0xc000 | sizeof(*header));
 
           const uint32_t kTTL = 86400;  // One day.
 
           // Size of RDATA which is a IPv4 or IPv6 address.
-          size_t rdata_size = qtype_ == dns_protocol::kTypeA
-                                  ? IPAddress::kIPv4AddressSize
-                                  : IPAddress::kIPv6AddressSize;
+          EXPECT_TRUE(result_.ip.IsValid());
+          size_t rdata_size = result_.ip.size();
 
           // 12 is the sum of sizes of the compressed name reference, TYPE,
           // CLASS, TTL and RDLENGTH.
           size_t answer_size = 12 + rdata_size;
 
-          // Write answer with loopback IP address.
+          // Write the answer using the expected IP address.
           header->ancount = base::HostToNet16(1);
           base::BigEndianWriter writer(buffer + nbytes, answer_size);
           writer.WriteU16(kPointerToQueryName);
           writer.WriteU16(qtype_);
           writer.WriteU16(dns_protocol::kClassIN);
           writer.WriteU32(kTTL);
           writer.WriteU16(static_cast<uint16_t>(rdata_size));
-          if (qtype_ == dns_protocol::kTypeA) {
-            char kIPv4Loopback[] = { 0x7f, 0, 0, 1 };
-            writer.WriteBytes(kIPv4Loopback, sizeof(kIPv4Loopback));
-          } else {
-            char kIPv6Loopback[] = { 0, 0, 0, 0, 0, 0, 0, 0,
-                                     0, 0, 0, 0, 0, 0, 0, 1 };
-            writer.WriteBytes(kIPv6Loopback, sizeof(kIPv6Loopback));
-          }
+          writer.WriteBytes(result_.ip.bytes().data(),
+                            result_.ip.bytes().size());

[mmenke, 2016/12/13 19:24:15]

nit:  result_.ip.bytes().size() -> size, or remove rdata_size and just inline
it?  getting the size for the rdata two different places in two adjacent lines
seems weird.

[eroman, 2016/12/13 22:09:04]

Done.

           nbytes += answer_size;
         }
         EXPECT_TRUE(response.InitParse(nbytes, query));
         callback_.Run(this, OK, &response);
       } break;
       case MockDnsClientRule::FAIL:
         callback_.Run(this, ERR_NAME_NOT_RESOLVED, NULL);
         break;
       case MockDnsClientRule::TIMEOUT:
         callback_.Run(this, ERR_DNS_TIMED_OUT, NULL);
@@ skipping 80 matching lines @@
 
 std::unique_ptr<const base::Value> MockDnsClient::GetPersistentData() const {
   return std::unique_ptr<const base::Value>();
 }
 
 void MockDnsClient::CompleteDelayedTransactions() {
   factory_->CompleteDelayedTransactions();
 }
 
 }  // namespace net