Redirect DNS for redir://

Run a fake stub DNS resolver at the same port with redir://.

src/net/BUILD.gn

@@ -2382,6 +2382,8 @@ if (!is_ios && !is_android) {
       "tools/naive/naive_proxy_bin.cc",
       "tools/naive/http_proxy_socket.cc",
       "tools/naive/http_proxy_socket.h",
+      "tools/naive/redirect_resolver.h",
+      "tools/naive/redirect_resolver.cc",
       "tools/naive/socks5_server_socket.cc",
       "tools/naive/socks5_server_socket.h",
     ]

src/net/tools/naive/naive_connection.cc

@@ -24,6 +24,7 @@
 #include "net/socket/stream_socket.h"
 #include "net/spdy/spdy_session.h"
 #include "net/tools/naive/http_proxy_socket.h"
+#include "net/tools/naive/redirect_resolver.h"
 #include "net/tools/naive/socks5_server_socket.h"
 
 #if defined(OS_LINUX)
@@ -52,6 +53,7 @@ NaiveConnection::NaiveConnection(
     const ProxyInfo& proxy_info,
     const SSLConfig& server_ssl_config,
     const SSLConfig& proxy_ssl_config,
+    RedirectResolver* resolver,
     HttpNetworkSession* session,
     const NetLogWithSource& net_log,
     std::unique_ptr<StreamSocket> accepted_socket,
@@ -62,6 +64,7 @@ NaiveConnection::NaiveConnection(
       proxy_info_(proxy_info),
       server_ssl_config_(server_ssl_config),
       proxy_ssl_config_(proxy_ssl_config),
+      resolver_(resolver),
       session_(session),
       net_log_(net_log),
       next_state_(STATE_NONE),
@@ -208,7 +211,17 @@ int NaiveConnection::DoConnectServer() {
     if (rv == 0) {
       IPEndPoint ipe;
       if (ipe.FromSockAddr(dst.addr, dst.addr_len)) {
-        origin = HostPortPair::FromIPEndPoint(ipe);
+        const auto& addr = ipe.address();
+        auto name = resolver_->FindNameByAddress(addr);
+        if (!name.empty()) {
+          origin = HostPortPair(name, ipe.port());
+        } else if (!resolver_->IsInResolvedRange(addr)) {
+          origin = HostPortPair::FromIPEndPoint(ipe);
+        } else {
+          LOG(ERROR) << "Connection " << id_ << " to unresolved name for "
+                     << addr.ToString();
+          return ERR_ADDRESS_INVALID;
+        }
       }
     }
 #else

src/net/tools/naive/naive_connection.h

@@ -27,6 +27,7 @@ class ProxyInfo;
 class StreamSocket;
 struct NetworkTrafficAnnotationTag;
 struct SSLConfig;
+class RedirectResolver;
 
 class NaiveConnection {
  public:
@@ -52,6 +53,7 @@ class NaiveConnection {
                   const ProxyInfo& proxy_info,
                   const SSLConfig& server_ssl_config,
                   const SSLConfig& proxy_ssl_config,
+                  RedirectResolver* resolver,
                   HttpNetworkSession* session,
                   const NetLogWithSource& net_log,
                   std::unique_ptr<StreamSocket> accepted_socket,
@@ -103,6 +105,7 @@ class NaiveConnection {
   const ProxyInfo& proxy_info_;
   const SSLConfig& server_ssl_config_;
   const SSLConfig& proxy_ssl_config_;
+  RedirectResolver* resolver_;
   HttpNetworkSession* session_;
   const NetLogWithSource& net_log_;
 

src/net/tools/naive/naive_proxy.cc

@@ -28,11 +28,13 @@ namespace net {
 NaiveProxy::NaiveProxy(std::unique_ptr<ServerSocket> listen_socket,
                        NaiveConnection::Protocol protocol,
                        bool use_padding,
+                       RedirectResolver* resolver,
                        HttpNetworkSession* session,
                        const NetworkTrafficAnnotationTag& traffic_annotation)
     : listen_socket_(std::move(listen_socket)),
       protocol_(protocol),
       use_padding_(use_padding),
+      resolver_(resolver),
       session_(session),
       net_log_(
           NetLogWithSource::Make(session->net_log(), NetLogSourceType::NONE)),
@@ -110,7 +112,7 @@ void NaiveProxy::DoConnect() {
   }
   auto connection_ptr = std::make_unique<NaiveConnection>(
       ++last_id_, protocol_, pad_direction, proxy_info_, server_ssl_config_,
-      proxy_ssl_config_, session_, net_log_, std::move(socket),
+      proxy_ssl_config_, resolver_, session_, net_log_, std::move(socket),
       traffic_annotation_);
   auto* connection = connection_ptr.get();
   connection_by_id_[connection->id()] = std::move(connection_ptr);

src/net/tools/naive/naive_proxy.h

@@ -25,12 +25,14 @@ class NaiveConnection;
 class ServerSocket;
 class StreamSocket;
 struct NetworkTrafficAnnotationTag;
+class RedirectResolver;
 
 class NaiveProxy {
  public:
   NaiveProxy(std::unique_ptr<ServerSocket> server_socket,
              NaiveConnection::Protocol protocol,
              bool use_padding,
+             RedirectResolver* resolver,
              HttpNetworkSession* session,
              const NetworkTrafficAnnotationTag& traffic_annotation);
   ~NaiveProxy();
@@ -58,6 +60,7 @@ class NaiveProxy {
   ProxyInfo proxy_info_;
   SSLConfig server_ssl_config_;
   SSLConfig proxy_ssl_config_;
+  RedirectResolver* resolver_;
   HttpNetworkSession* session_;
   NetLogWithSource net_log_;
 

src/net/tools/naive/naive_proxy_bin.cc

@@ -47,8 +47,10 @@
 #include "net/socket/client_socket_pool_manager.h"
 #include "net/socket/ssl_client_socket.h"
 #include "net/socket/tcp_server_socket.h"
+#include "net/socket/udp_server_socket.h"
 #include "net/ssl/ssl_key_logger_impl.h"
 #include "net/tools/naive/naive_proxy.h"
+#include "net/tools/naive/redirect_resolver.h"
 #include "net/traffic_annotation/network_traffic_annotation.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_builder.h"
@@ -74,6 +76,7 @@ struct CommandLine {
   std::string proxy;
   bool padding;
   std::string host_resolver_rules;
+  std::string resolver_range;
   bool no_log;
   base::FilePath log;
   base::FilePath log_net_log;
@@ -89,6 +92,8 @@ struct Params {
   std::string proxy_user;
   std::string proxy_pass;
   std::string host_resolver_rules;
+  net::IPAddress resolver_range;
+  size_t resolver_prefix;
   logging::LoggingSettings log_settings;
   base::FilePath net_log_path;
   base::FilePath ssl_key_path;
@@ -176,6 +181,7 @@ void GetCommandLine(const base::CommandLine& proc, CommandLine* cmdline) {
                  "                           proto: https, quic\n"
                  "--padding                  Use padding\n"
                  "--host-resolver-rules=...  Resolver rules\n"
+                 "--resolver-range=...       Redirect resolver range\n"
                  "--log[=<path>]             Log to stderr, or file\n"
                  "--log-net-log=<path>       Save NetLog\n"
                  "--ssl-key-log-file=<path>  Save SSL keys for Wireshark\n"
@@ -193,6 +199,7 @@ void GetCommandLine(const base::CommandLine& proc, CommandLine* cmdline) {
   cmdline->padding = proc.HasSwitch("padding");
   cmdline->host_resolver_rules =
       proc.GetSwitchValueASCII("host-resolver-rules");
+  cmdline->resolver_range = proc.GetSwitchValueASCII("resolver-range");
   cmdline->no_log = !proc.HasSwitch("log");
   cmdline->log = proc.GetSwitchValuePath("log");
   cmdline->log_net_log = proc.GetSwitchValuePath("log-net-log");
@@ -228,6 +235,9 @@ void GetCommandLineFromConfig(const base::FilePath& config_path,
     cmdline->host_resolver_rules =
         value->FindKey("host-resolver-rules")->GetString();
   }
+  if (value->FindKeyOfType("resolver-range", base::Value::Type::STRING)) {
+    cmdline->resolver_range = value->FindKey("resolver-range")->GetString();
+  }
   cmdline->no_log = true;
   if (value->FindKeyOfType("log", base::Value::Type::STRING)) {
     cmdline->no_log = false;
@@ -267,8 +277,13 @@ bool ParseCommandLine(const CommandLine& cmdline, Params* params) {
       params->protocol = net::NaiveConnection::kHttp;
       params->listen_port = 8080;
     } else if (url.scheme() == "redir") {
+#if defined(OS_LINUX)
       params->protocol = net::NaiveConnection::kRedir;
       params->listen_port = 1080;
+#else
+      std::cerr << "Redir protocol only supports Linux." << std::endl;
+      return false;
+#endif
     } else {
       std::cerr << "Invalid scheme in --listen" << std::endl;
       return false;
@@ -311,6 +326,22 @@ bool ParseCommandLine(const CommandLine& cmdline, Params* params) {
 
   params->host_resolver_rules = cmdline.host_resolver_rules;
 
+  if (params->protocol == net::NaiveConnection::kRedir) {
+    std::string range = "100.64.0.0/10";
+    if (!cmdline.resolver_range.empty())
+      range = cmdline.resolver_range;
+
+    if (!net::ParseCIDRBlock(range, &params->resolver_range,
+                             &params->resolver_prefix)) {
+      std::cerr << "Invalid resolver range" << std::endl;
+      return false;
+    }
+    if (params->resolver_range.IsIPv6()) {
+      std::cerr << "IPv6 resolver range not supported" << std::endl;
+      return false;
+    }
+  }
+
   if (!cmdline.no_log) {
     if (!cmdline.log.empty()) {
       params->log_settings.logging_dest = logging::LOG_TO_FILE;
@@ -458,8 +489,32 @@ int main(int argc, char* argv[]) {
   LOG(INFO) << "Listening on " << params.listen_addr << ":"
             << params.listen_port;
 
+  std::unique_ptr<net::RedirectResolver> resolver;
+  if (params.protocol == net::NaiveConnection::kRedir) {
+    auto resolver_socket =
+        std::make_unique<net::UDPServerSocket>(net_log, net::NetLogSource());
+    resolver_socket->AllowAddressReuse();
+    net::IPAddress listen_addr;
+    if (!listen_addr.AssignFromIPLiteral(params.listen_addr)) {
+      LOG(ERROR) << "Failed to open resolver: " << net::ERR_ADDRESS_INVALID;
+      return EXIT_FAILURE;
+    }
+
+    result = resolver_socket->Listen(
+        net::IPEndPoint(listen_addr, params.listen_port));
+    if (result != net::OK) {
+      LOG(ERROR) << "Failed to open resolver: " << result;
+      return EXIT_FAILURE;
+    }
+
+    resolver = std::make_unique<net::RedirectResolver>(
+        std::move(resolver_socket), params.resolver_range,
+        params.resolver_prefix);
+  }
+
   net::NaiveProxy naive_proxy(std::move(listen_socket), params.protocol,
-                              params.use_padding, session, kTrafficAnnotation);
+                              params.use_padding, resolver.get(), session,
+                              kTrafficAnnotation);
 
   base::RunLoop().Run();
 

src/net/tools/naive/redirect_resolver.cc

@@ -0,0 +1,241 @@
+// Copyright 2019 klzgrad <kizdiv@gmail.com>. 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/tools/naive/redirect_resolver.h"
+
+#include <cstring>
+#include <iterator>
+#include <utility>
+
+#include "base/logging.h"
+#include "base/optional.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/dns/dns_query.h"
+#include "net/dns/dns_response.h"
+#include "net/dns/dns_util.h"
+#include "net/socket/datagram_server_socket.h"
+
+namespace {
+constexpr int kUdpReadBufferSize = 1024;
+constexpr int kResolutionTtl = 60;
+constexpr int kResolutionRecycleTime = 60 * 5;
+
+std::string PackedIPv4ToString(uint32_t addr) {
+  return net::IPAddress(addr >> 24, addr >> 16, addr >> 8, addr).ToString();
+}
+}  // namespace
+
+namespace net {
+
+Resolution::Resolution() = default;
+
+Resolution::~Resolution() = default;
+
+RedirectResolver::RedirectResolver(std::unique_ptr<DatagramServerSocket> socket,
+                                   const IPAddress& range,
+                                   size_t prefix)
+    : socket_(std::move(socket)),
+      range_(range),
+      prefix_(prefix),
+      offset_(0),
+      buffer_(base::MakeRefCounted<IOBufferWithSize>(kUdpReadBufferSize)) {
+  DCHECK(socket_);
+  // Start accepting connections in next run loop in case when delegate is not
+  // ready to get callbacks.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::BindOnce(&RedirectResolver::DoRead,
+                                weak_ptr_factory_.GetWeakPtr()));
+}
+
+RedirectResolver::~RedirectResolver() = default;
+
+void RedirectResolver::DoRead() {
+  for (;;) {
+    int rv = socket_->RecvFrom(
+        buffer_.get(), kUdpReadBufferSize, &recv_address_,
+        base::BindOnce(&RedirectResolver::OnRecv, base::Unretained(this)));
+    if (rv == ERR_IO_PENDING)
+      return;
+    rv = HandleReadResult(rv);
+    if (rv == ERR_IO_PENDING)
+      return;
+    if (rv < 0) {
+      LOG(INFO) << "DoRead: ignoring error " << rv;
+    }
+  }
+}
+
+void RedirectResolver::OnRecv(int result) {
+  int rv;
+  rv = HandleReadResult(result);
+  if (rv == ERR_IO_PENDING)
+    return;
+  if (rv < 0) {
+    LOG(INFO) << "OnRecv: ignoring error " << result;
+  }
+
+  DoRead();
+}
+
+void RedirectResolver::OnSend(int result) {
+  if (result < 0) {
+    LOG(INFO) << "OnSend: ignoring error " << result;
+  }
+
+  DoRead();
+}
+
+int RedirectResolver::HandleReadResult(int result) {
+  if (result < 0)
+    return result;
+
+  DnsQuery query(buffer_.get());
+  if (!query.Parse(result)) {
+    LOG(INFO) << "Malformed DNS query from " << recv_address_.ToString();
+    return ERR_INVALID_ARGUMENT;
+  }
+
+  int size;
+  if (query.qtype() == dns_protocol::kTypeA) {
+    Resolution res;
+
+    auto name = DNSDomainToString(query.qname());
+
+    auto by_name_lookup = resolution_by_name_.emplace(name, resolutions_.end());
+    auto by_name = by_name_lookup.first;
+    bool has_name = !by_name_lookup.second;
+    if (has_name) {
+      auto res_it = by_name->second;
+      auto by_addr = res_it->by_addr;
+      uint32_t addr = res_it->addr;
+
+      resolutions_.erase(res_it);
+      resolutions_.emplace_back();
+      res_it = std::prev(resolutions_.end());
+
+      by_name->second = res_it;
+      by_addr->second = res_it;
+      res_it->addr = addr;
+      res_it->name = name;
+      res_it->time = base::TimeTicks::Now();
+      res_it->by_name = by_name;
+      res_it->by_addr = by_addr;
+    } else {
+      uint32_t addr = (range_.bytes()[0] << 24) | (range_.bytes()[1] << 16) |
+                      (range_.bytes()[2] << 8) | range_.bytes()[3];
+      uint32_t subnet = ~0U >> prefix_;
+      addr &= ~subnet;
+      addr += offset_;
+      offset_ = (offset_ + 1) & subnet;
+
+      auto by_addr_lookup =
+          resolution_by_addr_.emplace(addr, resolutions_.end());
+      auto by_addr = by_addr_lookup.first;
+      bool has_addr = !by_addr_lookup.second;
+      if (has_addr) {
+        // Too few available addresses. Overwrites old one.
+        auto res_it = by_addr->second;
+
+        LOG(INFO) << "Overwrite " << res_it->name << " "
+                  << PackedIPv4ToString(res_it->addr) << " with " << name << " "
+                  << PackedIPv4ToString(addr);
+        resolution_by_name_.erase(res_it->by_name);
+        resolutions_.erase(res_it);
+        resolutions_.emplace_back();
+        res_it = std::prev(resolutions_.end());
+
+        by_name->second = res_it;
+        by_addr->second = res_it;
+        res_it->addr = addr;
+        res_it->name = name;
+        res_it->time = base::TimeTicks::Now();
+        res_it->by_name = by_name;
+        res_it->by_addr = by_addr;
+      } else {
+        LOG(INFO) << "Add " << name << " " << PackedIPv4ToString(addr);
+        resolutions_.emplace_back();
+        auto res_it = std::prev(resolutions_.end());
+
+        by_name->second = res_it;
+        by_addr->second = res_it;
+        res_it->addr = addr;
+        res_it->name = name;
+        res_it->time = base::TimeTicks::Now();
+        res_it->by_name = by_name;
+        res_it->by_addr = by_addr;
+
+        // Collects garbage.
+        auto now = base::TimeTicks::Now();
+        for (auto it = resolutions_.begin();
+             it != resolutions_.end() &&
+             (now - it->time).InSeconds() > kResolutionRecycleTime;) {
+          auto next = std::next(it);
+          LOG(INFO) << "Drop " << it->name << " "
+                    << PackedIPv4ToString(it->addr);
+          resolution_by_name_.erase(it->by_name);
+          resolution_by_addr_.erase(it->by_addr);
+          resolutions_.erase(it);
+          it = next;
+        }
+      }
+    }
+
+    DnsResourceRecord record;
+    record.name = name;
+    record.type = dns_protocol::kTypeA;
+    record.klass = dns_protocol::kClassIN;
+    record.ttl = kResolutionTtl;
+    uint32_t addr = by_name->second->addr;
+    record.SetOwnedRdata(IPAddressToPackedString(
+        IPAddress(addr >> 24, addr >> 16, addr >> 8, addr)));
+    base::Optional<DnsQuery> query_opt(base::in_place, query.id(),
+                                       query.qname(), query.qtype());
+    DnsResponse response(query.id(), /*is_authoritative=*/false,
+                         /*answers=*/{std::move(record)},
+                         /*authority_records=*/{}, /*additional_records=*/{},
+                         query_opt);
+    size = response.io_buffer_size();
+    if (size > buffer_->size() || !response.io_buffer()) {
+      return ERR_NO_BUFFER_SPACE;
+    }
+    std::memcpy(buffer_->data(), response.io_buffer()->data(), size);
+  } else {
+    base::Optional<DnsQuery> query_opt(base::in_place, query.id(),
+                                       query.qname(), query.qtype());
+    DnsResponse response(query.id(), /*is_authoritative=*/false, /*answers=*/{},
+                         /*authority_records=*/{}, /*additional_records=*/{},
+                         query_opt, dns_protocol::kRcodeSERVFAIL);
+    size = response.io_buffer_size();
+    if (size > buffer_->size() || !response.io_buffer()) {
+      return ERR_NO_BUFFER_SPACE;
+    }
+    std::memcpy(buffer_->data(), response.io_buffer()->data(), size);
+  }
+
+  return socket_->SendTo(
+      buffer_.get(), size, recv_address_,
+      base::BindOnce(&RedirectResolver::OnSend, base::Unretained(this)));
+}
+
+bool RedirectResolver::IsInResolvedRange(const IPAddress& address) const {
+  if (!address.IsIPv4())
+    return false;
+  return IPAddressMatchesPrefix(address, range_, prefix_);
+}
+
+std::string RedirectResolver::FindNameByAddress(
+    const IPAddress& address) const {
+  if (!address.IsIPv4())
+    return {};
+  uint32_t addr = (address.bytes()[0] << 24) | (address.bytes()[1] << 16) |
+                  (address.bytes()[2] << 8) | address.bytes()[3];
+  auto by_addr = resolution_by_addr_.find(addr);
+  if (by_addr == resolution_by_addr_.end())
+    return {};
+  return by_addr->second->name;
+}
+
+}  // namespace net

src/net/tools/naive/redirect_resolver.h

@@ -0,0 +1,70 @@
+// Copyright 2019 klzgrad <kizdiv@gmail.com>. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_TOOLS_NAIVE_REDIRECT_RESOLVER_H_
+#define NET_TOOLS_NAIVE_REDIRECT_RESOLVER_H_
+
+#include <cstdint>
+#include <list>
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "net/base/ip_address.h"
+#include "net/base/ip_endpoint.h"
+
+namespace net {
+
+class DatagramServerSocket;
+class IOBufferWithSize;
+
+struct Resolution {
+  Resolution();
+  ~Resolution();
+
+  uint32_t addr;
+  std::string name;
+  base::TimeTicks time;
+  std::map<std::string, std::list<Resolution>::iterator>::iterator by_name;
+  std::map<uint32_t, std::list<Resolution>::iterator>::iterator by_addr;
+};
+
+class RedirectResolver {
+ public:
+  RedirectResolver(std::unique_ptr<DatagramServerSocket> socket,
+                   const IPAddress& range,
+                   size_t prefix);
+  ~RedirectResolver();
+
+  bool IsInResolvedRange(const IPAddress& address) const;
+  std::string FindNameByAddress(const IPAddress& address) const;
+
+ private:
+  void DoRead();
+  void OnRecv(int result);
+  void OnSend(int result);
+  int HandleReadResult(int result);
+
+  std::unique_ptr<DatagramServerSocket> socket_;
+  IPAddress range_;
+  size_t prefix_;
+  uint32_t offset_;
+  scoped_refptr<IOBufferWithSize> buffer_;
+  IPEndPoint recv_address_;
+
+  std::map<std::string, std::list<Resolution>::iterator> resolution_by_name_;
+  std::map<uint32_t, std::list<Resolution>::iterator> resolution_by_addr_;
+  std::list<Resolution> resolutions_;
+
+  base::WeakPtrFactory<RedirectResolver> weak_ptr_factory_{this};
+
+  DISALLOW_COPY_AND_ASSIGN(RedirectResolver);
+};
+
+}  // namespace net
+#endif  // NET_TOOLS_NAIVE_REDIRECT_RESOLVER_H_