Command line utility to run the HostResolver. ...

net/tools/hresolv/hresolv.cc

+// Copyright (c) 2009 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.
+
+// hrseolv is a command line utility which runs the HostResolver in the
+// Chromium network stack.
+//
+// The user specifies the hosts to lookup and when to look them up.
+// The hosts must be specified in order.
+// The hosts can be contained in a file or on the command line. If no
+// time is specified, the resolv is assumed to be the same time as the
+// previous host - which is an offset of 0 for the very first host.
+//
+// The user can also control whether the lookups happen asynchronously
+// or synchronously by specifying --async on the command line.
+//
+// Future ideas:
+//   Specify whether the lookup is speculative.
+//   Interleave synchronous and asynchronous lookups.
+//   Specify the address family.
+
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <ws2tcpip.h>
+#else
+#include <netdb.h>
+#endif
+#include <stdio.h>
+#include <string>
+
+#include "base/at_exit.h"
+#include "base/command_line.h"
+#include "base/condition_variable.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/string_util.h"
+#include "base/thread.h"
+#include "base/time.h"
+#include "base/waitable_event.h"
+#include "net/base/address_list.h"
+#include "net/base/completion_callback.h"
+#include "net/base/host_resolver_impl.h"
+#include "net/base/net_errors.h"
+#include "net/base/net_util.h"
+
+struct FlagName {
+  int flag;
+  const char* name;
+};
+
+static const FlagName kAddrinfoFlagNames[] = {
+  {AI_PASSIVE, "AI_PASSIVE"},
+  {AI_CANONNAME, "AI_CANONNAME"},
+  {AI_NUMERICHOST, "AI_NUMERICHOST"},
+  {AI_V4MAPPED, "AI_V4MAPPED"},
+  {AI_ALL, "AI_ALL"},
+  {AI_ADDRCONFIG, "AI_ADDRCONFIG"},
+#if defined(OS_LINUX) || defined(OS_WIN)
+  {AI_NUMERICSERV, "AI_NUMERICSERV"},
+#endif
+};
+
+std::string FormatAddrinfoFlags(int ai_flags) {
+  std::string flag_names;
+  for (unsigned int i = 0; i < arraysize(kAddrinfoFlagNames); ++i) {
+    const FlagName& flag_name = kAddrinfoFlagNames[i];
+    if (ai_flags & flag_name.flag) {
+      ai_flags &= ~flag_name.flag;
+      if (!flag_names.empty()) {
+        flag_names += "|";
+      }
+      flag_names += flag_name.name;
+    }
+  }
+  if (ai_flags) {
+   if (!flag_names.empty()) {
+     flag_names += "|";
+   }
+   flag_names += StringPrintf("0x%x", ai_flags);
+  }
+  return flag_names;
+}
+
+const char* GetNameOfFlag(const FlagName* flag_names,
+                          unsigned int num_flag_names,
+                          int flag) {
+  for (unsigned int i = 0; i < num_flag_names; ++i) {
+    const FlagName& flag_name = flag_names[i];
+    if (flag_name.flag == flag) {
+      return flag_name.name;
+    }
+  }
+  return "UNKNOWN";
+}
+
+static const FlagName kFamilyFlagNames[] = {
+  {AF_UNSPEC, "AF_UNSPEC"},

[eroman, 2009/12/09 23:00:31]

style-nit: I'm not sure on what the indentation should be here (2 spaces or 4
spaces). I don't much care either way (as long as you are consistent throughout,
which you are), but was curious if you knew offhand which way "correct"  :)

+  {AF_INET, "AF_INET"},
+  {AF_INET6, "AF_INET6"},
+};
+
+const char* FormatAddrinfoFamily(int ai_family) {
+  return GetNameOfFlag(kFamilyFlagNames,
+                       arraysize(kFamilyFlagNames),
+                       ai_family);
+}
+
+static const FlagName kSocktypeFlagNames[] = {
+  {SOCK_STREAM, "SOCK_STREAM"},
+  {SOCK_DGRAM, "SOCK_DGRAM"},
+  {SOCK_RAW, "SOCK_RAW"},
+};
+
+const char* FormatAddrinfoSocktype(int ai_socktype) {
+  return GetNameOfFlag(kSocktypeFlagNames,
+                       arraysize(kSocktypeFlagNames),
+                       ai_socktype);
+}
+
+static const FlagName kProtocolFlagNames[] = {
+  {IPPROTO_TCP, "IPPROTO_TCP"},
+  {IPPROTO_UDP, "IPPROTO_UDP"},
+};
+
+const char* FormatAddrinfoProtocol(int ai_protocol) {
+  return GetNameOfFlag(kProtocolFlagNames,
+                       arraysize(kProtocolFlagNames),
+                       ai_protocol);
+}
+
+std::string FormatAddrinfoDetails(const struct addrinfo& ai,
+                                  const char* indent) {
+  std::string ai_flags = FormatAddrinfoFlags(ai.ai_flags);
+  const char* ai_family = FormatAddrinfoFamily(ai.ai_family);
+  const char* ai_socktype = FormatAddrinfoSocktype(ai.ai_socktype);
+  const char* ai_protocol = FormatAddrinfoProtocol(ai.ai_protocol);
+  std::string ai_addr = net::NetAddressToString(&ai);
+  std::string ai_canonname;
+  if (ai.ai_canonname) {
+    ai_canonname = StringPrintf("%s  ai_canonname: %s\n",
+                                indent,
+                                ai.ai_canonname);
+  }
+  return StringPrintf("%saddrinfo {\n"
+                      "%s  ai_flags: %s\n"
+                      "%s  ai_family: %s\n"
+                      "%s  ai_socktype: %s\n"
+                      "%s  ai_protocol: %s\n"
+                      "%s  ai_addrlen: %d\n"
+                      "%s  ai_addr: %s\n"
+                      "%s"
+                      "%s}\n",
+                      indent,
+                      indent, ai_flags.c_str(),
+                      indent, ai_family,
+                      indent, ai_socktype,
+                      indent, ai_protocol,
+                      indent, ai.ai_addrlen,
+                      indent, ai_addr.c_str(),
+                      ai_canonname.c_str(),
+                      indent);
+}
+
+std::string FormatAddressList(const net::AddressList& address_list,
+                              const std::string& host) {
+  std::string ret_string;
+  StringAppendF(&ret_string, "AddressList {\n");
+  StringAppendF(&ret_string, "  Host: %s\n", host.c_str());
+  for (const struct addrinfo* it = address_list.head();

[eroman, 2009/12/09 23:00:31]

style-nit: I suggest using a more descriptive name than |it|. Perhaps
|cur_address|

+       it != NULL;

[eroman, 2009/12/09 23:00:31]

minor-style-nit: Omit the "!= NULL"

+       it = it->ai_next) {
+    StringAppendF(&ret_string, "%s", FormatAddrinfoDetails(*it, "  ").c_str());
+  }
+  StringAppendF(&ret_string, "}\n");
+  return ret_string;
+}
+
+class ResolverInvoker;
+
+// DelayedResolve contains state for a DNS resolution to be performed later.
+class DelayedResolve : public base::RefCounted<DelayedResolve> {
+ public:
+  DelayedResolve(const std::string& host, bool is_async,
+                 net::HostResolver* resolver,
+                 ResolverInvoker* invoker)
+      : host_(host),
+        address_list_(),

[eroman, 2009/12/09 23:00:31]

nit: omit default constructor calls.

+        is_async_(is_async),
+        resolver_(resolver),
+        invoker_(invoker),
+        ALLOW_THIS_IN_INITIALIZER_LIST(
+            io_callback_(this, &DelayedResolve::OnResolveComplete)) {
+   }
+
+  void Start() {
+    net::CompletionCallback* callback = (is_async_) ? &io_callback_ : NULL;
+    net::HostResolver::RequestInfo request_info(host_, 80);
+    int rv = resolver_->Resolve(request_info,
+                                &address_list_,
+                                callback,
+                                NULL,
+                                NULL);
+    if (rv != net::ERR_IO_PENDING) {
+      OnResolveComplete(rv);
+    }
+  }
+
+ private:
+

[eroman, 2009/12/09 23:00:31]

nit: please delete this blank line.

+  // Without this, VC++ complains about the private destructor below.
+  friend class base::RefCounted<DelayedResolve>;
+
+  // The destructor is called by Release.
+  ~DelayedResolve() {}
+
+  void OnResolveComplete(int result);
+
+  std::string host_;
+  net::AddressList address_list_;
+  bool is_async_;
+  scoped_refptr<net::HostResolver> resolver_;
+  ResolverInvoker* invoker_;
+  net::CompletionCallbackImpl<DelayedResolve> io_callback_;
+};
+
+
+struct HostAndTime {
+  // The host to resolve, i.e. www.google.com
+  std::string host;
+  // Time since the start of this program to actually kick off the resolution.
+  int delta_in_milliseconds;
+};
+
+// Invokes a sequence of host resolutions at specified times.
+class ResolverInvoker {
+ public:
+  explicit ResolverInvoker(net::HostResolver* resolver)
+      : message_loop_(MessageLoop::TYPE_DEFAULT),
+        resolver_(resolver),
+        remaining_requests_(0) {
+  }
+
+  ~ResolverInvoker() {
+  }
+
+  // Resolves all specified hosts in the order provided. hosts_and_times is
+  // assumed to be ordered by the delta_in_milliseconds field. There is no
+  // guarantee that the resolutions will complete in the order specified when
+  // async is true. There is no guarantee that the DNS queries will be issued
+  // at exactly the time specified by delta_in_milliseconds, but they are
+  // guaranteed to be issued at a time >= delta_in_milliseconds.
+  //
+  // When async is true, HostResolver::Resolve will issue the DNS lookups
+  // asynchronously - this can be used to have multiple requests in flight at
+  // the same time.
+  //
+  // ResolveAll will block until all resolutions are complete.
+  void ResolveAll(const std::vector<HostAndTime>& hosts_and_times,
+                  bool async) {
+    // Schedule all tasks on our message loop, and then run.
+    int num_requests = hosts_and_times.size();
+    remaining_requests_ = num_requests;
+    for (int i = 0; i < num_requests; ++i) {
+      const HostAndTime& host_and_time = hosts_and_times[i];
+      const std::string& host = host_and_time.host;
+      DelayedResolve* resolve_request = new DelayedResolve(host,
+        async, resolver_, this);
+      resolve_request->AddRef();

[eroman, 2009/12/09 23:00:31]

nit: I recommend documenting that it is balanced by ::OnResolveComplete().

+      message_loop_.PostDelayedTask(
+          FROM_HERE,
+          NewRunnableMethod(resolve_request, &DelayedResolve::Start),
+          host_and_time.delta_in_milliseconds);
+    }
+    message_loop_.Run();
+  }
+
+ private:
+  friend class DelayedResolve;
+
+  void OnResolved(int err, net::AddressList* address_list,
+                  const std::string& host) {
+    if (err == net::OK) {
+      printf("%s", FormatAddressList(*address_list, host).c_str());
+    } else {
+      printf("Error resolving %s\n", host.c_str());
+    }
+    DCHECK(remaining_requests_ > 0);
+    --remaining_requests_;
+    if (remaining_requests_ == 0) {
+      message_loop_.Quit();
+    }
+  }
+
+  MessageLoop message_loop_;
+  scoped_refptr<net::HostResolver> resolver_;
+  int remaining_requests_;
+};
+
+void DelayedResolve::OnResolveComplete(int result) {

[eroman, 2009/12/09 23:00:31]

nit: this definition could be arranged higher up in the file (i.e. nearer the
declaration of DelayedResolve, or inlined inside of DelayedResolve.

+  invoker_->OnResolved(result, &address_list_, host_);
+  this->Release();
+}
+
+struct CommandLineOptions {
+  CommandLineOptions()
+      : verbose(false),
+        async(false),
+        cache_size(100),
+        cache_ttl(50),
+        input_path() {
+  }
+
+  bool verbose;
+  bool async;
+  int cache_size;
+  int cache_ttl;
+  FilePath input_path;
+};
+
+const char* kAsync = "async";
+const char* kCacheSize = "cache-size";
+const char* kCacheTtl = "cache-ttl";
+const char* kInputPath = "input-path";
+
+// Parses the command line values. Returns false if there is a problem,
+// options otherwise.
+bool ParseCommandLine(CommandLine* command_line, CommandLineOptions* options) {
+  options->async = command_line->HasSwitch(kAsync);
+  if (command_line->HasSwitch(kCacheSize)) {
+    std::string cache_size = command_line->GetSwitchValueASCII(kCacheSize);
+    bool valid_size = StringToInt(cache_size, &options->cache_size);
+    if (valid_size) {
+      valid_size = options->cache_size >= 0;
+    }
+    if (!valid_size) {
+      printf("Invalid --cachesize value: %s\n", cache_size.c_str());
+      return false;
+    }
+  }
+
+  if (command_line->HasSwitch(kCacheTtl)) {
+    std::string cache_ttl = command_line->GetSwitchValueASCII(kCacheTtl);
+    bool valid_ttl = StringToInt(cache_ttl, &options->cache_ttl);
+    if (valid_ttl) {
+      valid_ttl = options->cache_ttl >= 0;
+    }
+    if (!valid_ttl) {
+      printf("Invalid --cachettl value: %s\n", cache_ttl.c_str());
+      return false;
+    }
+  }
+
+  if (command_line->HasSwitch(kInputPath)) {
+    options->input_path = command_line->GetSwitchValuePath(kInputPath);
+  }
+
+  return true;
+}
+
+bool ReadHostsAndTimesFromLooseValues(
+    const std::vector<std::wstring>& loose_args,
+    std::vector<HostAndTime>* hosts_and_times) {
+  std::vector<std::wstring>::const_iterator loose_args_end = loose_args.end();
+  for (std::vector<std::wstring>::const_iterator it = loose_args.begin();
+       it != loose_args_end;
+       ++it) {
+    // TODO(cbentzel): Read time offset.
+    HostAndTime host_and_time = {WideToASCII(*it), 0};
+    hosts_and_times->push_back(host_and_time);
+  }
+  return true;
+}
+
+bool ReadHostsAndTimesFromFile(const FilePath& path,
+                               std::vector<HostAndTime>* hosts_and_times) {
+  // TODO(cbentzel): There are smarter and safer ways to do this.
+  std::string file_contents;
+  if (!file_util::ReadFileToString(path, &file_contents)) {
+    return false;
+  }
+  std::vector<std::string> lines;
+  // TODO(cbentzel): This should probably handle CRLF-style separators as well.
+  // Maybe it's worth adding functionality like this to base tools.
+  SplitString(file_contents, '\n', &lines);
+  std::vector<std::string>::const_iterator line_end = lines.end();
+  int previous_timestamp = 0;
+  for (std::vector<std::string>::const_iterator it = lines.begin();
+       it != line_end;
+       ++it) {
+    std::vector<std::string> tokens;
+    SplitStringAlongWhitespace(*it, &tokens);
+    switch (tokens.size()) {
+      case 0:
+        // Unexpected, but keep going.
+        break;
+      case 1: {
+        HostAndTime host_and_time = {tokens[0], previous_timestamp};
+        hosts_and_times->push_back(host_and_time);
+        break;
+      }
+      case 2: {
+        int timestamp;
+        if (!StringToInt(tokens[1], &timestamp)) {
+          // Unexpected value - keep going.
+        }
+        if (timestamp < previous_timestamp) {
+          // Unexpected value - ignore.
+        }
+        previous_timestamp = timestamp;
+        HostAndTime host_and_time = {tokens[0], timestamp};
+        hosts_and_times->push_back(host_and_time);
+        break;
+      }
+      default:
+        DCHECK(false);
+        break;
+    }
+  }
+  return true;
+}
+
+int main(int argc, char** argv) {
+  base::AtExitManager at_exit_manager;
+  CommandLine::Init(argc, argv);
+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  CommandLineOptions options;
+  if (!ParseCommandLine(command_line, &options)) {
+    exit(1);
+  }
+
+  // Get the hosts and times - either from a file or command line options.
+  // TODO(cbentzel): Add stdin support to POSIX versions - not sure if
+  // there's an equivalent in Windows.
+  // TODO(cbentzel): If really large, may not want to spool the whole
+  // file into memory.
+  std::vector<HostAndTime> hosts_and_times;
+  if (options.input_path.empty()) {
+    if (!ReadHostsAndTimesFromLooseValues(command_line->GetLooseValues(),
+                                          &hosts_and_times)) {
+      exit(1);
+    }
+  } else {
+    if (!ReadHostsAndTimesFromFile(options.input_path, &hosts_and_times)) {
+      exit(1);
+    }
+  }
+
+  scoped_refptr<net::HostResolver> host_resolver(
+      new net::HostResolverImpl(NULL, options.cache_size, options.cache_ttl));

[eroman, 2009/12/09 23:00:31]

Depending who checks in first, someone will have some merging to do :)

I have a soon to come CL that changes the constructor:
http://codereview.chromium.org/464084/show

+  ResolverInvoker invoker(host_resolver.get());
+  invoker.ResolveAll(hosts_and_times, options.async);
+
+  CommandLine::Reset();
+  return 0;
+}