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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/nearby_sharing/network_traversal_ice_config_fetcher.h"
#include <optional>
#include "base/functional/bind.h"
#include "base/json/json_reader.h"
#include "base/strings/strcat.h"
#include "chrome/services/sharing/public/cpp/sharing_webrtc_metrics.h"
#include "google_apis/google_api_keys.h"
#include "net/base/load_flags.h"
#include "services/network/public/cpp/resource_request.h"
#include "services/network/public/cpp/shared_url_loader_factory.h"
#include "services/network/public/cpp/simple_url_loader.h"
#include "services/network/public/mojom/url_response_head.mojom.h"
namespace {
const char kNetworkTraversalIceConfigApiUrl[] =
"https://networktraversal.googleapis.com/v1alpha/iceconfig?key=";
// Response with 2 ice server configs takes ~1KB. A loose upper bound of 16KB is
// chosen to avoid breaking the flow in case the response has longer URLs in ice
// configs.
constexpr int kMaxBodySize = 16 * 1024;
const net::NetworkTrafficAnnotationTag kTrafficAnnotation =
net::DefineNetworkTrafficAnnotation("network_traversal_ice_config_fetcher",
R"(
semantics {
sender: "NetworkTraversalIceConfigFetcher"
description:
"Fetches ice server configurations for p2p webrtc connection as "
"described in "
"https://www.w3.org/TR/webrtc/#rtciceserver-dictionary."
trigger:
"User uses any Chrome cross-device sharing feature and selects one"
" of their devices to send the data to."
data: "No data is sent in the request."
destination: GOOGLE_OWNED_SERVICE
}
policy {
cookies_allowed: NO
setting:
"Users can disable this behavior by signing out of Chrome."
chrome_policy {
BrowserSignin {
policy_options {mode: MANDATORY}
BrowserSignin: 0
}
}
})");
bool IsLoaderSuccessful(const network::SimpleURLLoader* loader) {
DCHECK(loader);
if (loader->NetError() != net::OK) {
LOG(ERROR) << "NetworkTraversalIceConfigFetcher url loader network error: "
<< loader->NetError();
return false;
}
if (!loader->ResponseInfo() || !loader->ResponseInfo()->headers) {
LOG(ERROR) << "NetworkTraversalIceConfigFetcher invalid response or "
"missing headers";
return false;
}
// Success response codes are 2xx.
bool is_successful_response_code =
(loader->ResponseInfo()->headers->response_code() / 100) == 2;
if (!is_successful_response_code) {
LOG(ERROR)
<< "NetworkTraversalIceConfigFetcher non-successful response code: "
<< loader->ResponseInfo()->headers->response_code();
}
return is_successful_response_code;
}
std::vector<::sharing::mojom::IceServerPtr> GetDefaultIceServers() {
::sharing::mojom::IceServerPtr ice_server(::sharing::mojom::IceServer::New());
ice_server->urls.emplace_back("stun:stun.l.google.com:19302");
ice_server->urls.emplace_back("stun:stun1.l.google.com:19302");
ice_server->urls.emplace_back("stun:stun2.l.google.com:19302");
ice_server->urls.emplace_back("stun:stun3.l.google.com:19302");
ice_server->urls.emplace_back("stun:stun4.l.google.com:19302");
std::vector<::sharing::mojom::IceServerPtr> default_servers;
default_servers.push_back(std::move(ice_server));
return default_servers;
}
std::vector<::sharing::mojom::IceServerPtr> ParseIceConfigJson(
std::string json) {
std::vector<::sharing::mojom::IceServerPtr> ice_servers;
std::optional<base::Value> response = base::JSONReader::Read(json);
if (!response)
return ice_servers;
base::Value::List* ice_servers_json =
response->GetDict().FindList("iceServers");
if (!ice_servers_json)
return ice_servers;
for (base::Value& server : *ice_servers_json) {
base::Value::Dict& server_dict = server.GetDict();
const base::Value::List* urls_json = server_dict.FindList("urls");
if (!urls_json)
continue;
std::vector<GURL> urls;
for (const base::Value& url_json : *urls_json) {
const std::string* url = url_json.GetIfString();
if (!url)
continue;
urls.emplace_back(*url);
}
if (urls.empty())
continue;
::sharing::mojom::IceServerPtr ice_server(
::sharing::mojom::IceServer::New());
ice_server->urls = std::move(urls);
std::string* retrieved_username = server_dict.FindString("username");
if (retrieved_username)
ice_server->username.emplace(std::move(*retrieved_username));
std::string* retrieved_credential = server_dict.FindString("credential");
if (retrieved_credential)
ice_server->credential.emplace(std::move(*retrieved_credential));
ice_servers.push_back(std::move(ice_server));
}
return ice_servers;
}
void OnIceServersResponse(
::sharing::mojom::IceConfigFetcher::GetIceServersCallback callback,
std::unique_ptr<network::SimpleURLLoader> url_loader,
std::unique_ptr<std::string> response_body) {
std::vector<::sharing::mojom::IceServerPtr> ice_servers;
if (IsLoaderSuccessful(url_loader.get()) && response_body)
ice_servers = ParseIceConfigJson(*response_body);
sharing::LogWebRtcIceConfigFetched(ice_servers.size());
if (ice_servers.empty()) {
VLOG(1) << "NetworkTraversalIceConfigFetcher returning default ice servers";
ice_servers = GetDefaultIceServers();
}
std::move(callback).Run(std::move(ice_servers));
}
} // namespace
NetworkTraversalIceConfigFetcher::NetworkTraversalIceConfigFetcher(
scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory)
: url_loader_factory_(std::move(url_loader_factory)) {}
NetworkTraversalIceConfigFetcher::~NetworkTraversalIceConfigFetcher() = default;
void NetworkTraversalIceConfigFetcher::GetIceServers(
GetIceServersCallback callback) {
auto resource_request = std::make_unique<network::ResourceRequest>();
resource_request->url = GURL(base::StrCat(
{kNetworkTraversalIceConfigApiUrl, google_apis::GetSharingAPIKey()}));
resource_request->load_flags =
net::LOAD_BYPASS_CACHE | net::LOAD_DISABLE_CACHE;
resource_request->credentials_mode = network::mojom::CredentialsMode::kOmit;
resource_request->method = net::HttpRequestHeaders::kPostMethod;
resource_request->headers.SetHeader(net::HttpRequestHeaders::kContentType,
"application/json");
auto url_loader = network::SimpleURLLoader::Create(
std::move(resource_request), kTrafficAnnotation);
auto* url_loader_ptr = url_loader.get();
url_loader_ptr->DownloadToString(
url_loader_factory_.get(),
base::BindOnce(&OnIceServersResponse, std::move(callback),
std::move(url_loader)),
kMaxBodySize);
}
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