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[TOC]
双通道概述
指设备连接着WiFi的情况下，同时打开蜂窝通道，从而实现双通道同时进行网络请求，提高访问速度。
graph LR
client---|socket1| WiFi网卡 -->|socket1|Server
client---|socket2| 4G蜂窝网络网卡 -->|socket2| Server
Android系统下双通结合libCurl的方案概述
不同于iOS的权限简洁，能将网卡直接丢给libCurl使用。Android在native层使用4G网卡，需要费劲很多。
sequenceDiagram
native ->>+ java: 发起请求打开双通
java ->>+ Android OS: 向系统申请4G通道
Note over Android OS : 手机顶部状态栏的4G流量图标常驻
Android OS ->>- java: 持有SocketFactory
java ->>- native:回调开启成功
loop 网络请求
native -->> native:发起网络请求
native ->>+ java:通知创建socket
java ->>+ Android OS: 创建socket
java ->> java: 使用socket解析域名
Android OS ->>- java:已经绑定过目标IP的socket
java ->>- native:获取socket的fd
native ->>+ server: libcurl正常建连
server ->>- native: 完成数据传输
end
native ->>+ java:关闭4G通道
java ->>+ Android OS: 主动释放4G通道
Note over Android OS : 手机顶部状态栏上4G流量图标消失
Android OS ->>- java: 释放成功
java ->>- native:回调关闭成功
关于域名解析服务：
仅使用localHost时：
如果仅使用localHost，那么只需要java层面，用socket绑定域名，不需要额外代码，就能自动的在4G网卡上进行域名解析为ip。
查看socket绑定的ip是socket.getRemoteSocketAddress()
使用自有DNS服务
在指定socket目的IP时，必须主动区分当前socket出口的IP类型，不能讲IPv4与IPv6混用。如果结合自己的DNS方案，那就需要把IPv6作为判断的参数。这里的样例代码，也是仅仅是从已经建联的socket中取出ip地址，没有进一步复杂化。
传递java上层的socket到native
这里利用到的是ParcelFileDescriptor，在java层获取socket的描述符，直接丢给libCurl使用
问题概述
- 对比iOS的方案，Android环境下，libCurl不能直接绑定4G网卡，在Android系统层面，限制了直接使用4G网卡。
- Android系统绕不开Java层配合。
- Android上层保持4G通道的打开，libCurl仍然不能直接使用4G网卡。
- Android系统绕不开Java层创建network（可用这个创建socket）
- 开启与关闭双通，都需要C++层面通知到Java层。
代码说明
Android双通的基本使用
在普通的使用场景中，我们不关注SocketFactory，也不用关注域名解析，因为系统API返回的connect可以直接进行网络请求，而内部的域名解析细节可以完全忽略：network.openConnection(new URL(url));。
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
final String TAG = "NetworkCardInfo";
TlogUtils.d(TAG, "4g通道,尝试开启");
ConnectivityManager connectivityManager = (ConnectivityManager) getApplication().getSystemService(CONNECTIVITY_SERVICE);
NetworkRequest request = new NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
ConnectivityManager.NetworkCallback networkCallback = new ConnectivityManager.NetworkCallback() {
@Override
public void onAvailable(Network network) {
TlogUtils.d(TAG, "4g通道,已经开启");
// 用network进行网络请求
try {
HttpURLConnection urlConnection = (HttpURLConnection) network.openConnection(new URL(url));
int code = urlConnection.getResponseCode();
} catch (IOException e) {
e.printStackTrace();
}
}
};
connectivityManager.requestNetwork(request, networkCallback);
}
}
不成功的方案：libCurl直接绑定4G网卡
精准的获取蜂窝网卡名：
Android设备下，网卡非常多，想获取到有效的网卡，必须过滤网卡名，同时必须判断网卡下是否存在有效的IP：
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;
final class NetworkCardInfo {
private final static String TAG = "NetworkCardInfo";
/**
* 获取4G网卡名
*/
public static String getNetworkCardName(boolean isWifi) {
String networkCardNameKey = isWifi ? "wlan" : "rmnet";
final String tag = TAG + "," + networkCardNameKey;
NameAndIp nameAndIp = getNetworkCardInfoOfCellularImpl(networkCardNameKey, tag);
TlogUtils.i(tag, "获取到的网卡名:" + nameAndIp);
// if (isWifi) {
return nameAndIp.name;
// } else {
// return nameAndIp.ip;
// }
}
private static class NameAndIp {
private String name;
private String ip;
public NameAndIp(String name, String ip) {
this.name = name;
this.ip = ip;
}
@Override
public String toString() {
return "NameAndIp{" + "name='" + name + '\'' + ", ip='" + ip + '\'' + '}';
}
}
private static NameAndIp getNetworkCardInfoOfCellularImpl(String networkCardNameKey, String tag) {
try {
Enumeration nis = NetworkInterface.getNetworkInterfaces();
while (nis.hasMoreElements()) {
NetworkInterface ni = (NetworkInterface) nis.nextElement();
String name = ni.getName();
if (name == null) {
name = "";
}
String nameCompare = name.toLowerCase();
if (!nameCompare.contains(networkCardNameKey)) {
TlogUtils.d(tag, "网卡不符:" + name);
continue;
}
TlogUtils.d(tag, "网卡可疑:" + name);
Enumeration ias = ni.getInetAddresses();
while (ias.hasMoreElements()) {
InetAddress ia = ias.nextElement();
// // ipv6
// if(ia instanceof Inet6Address) {
// continue;
// }
String ip = ia.getHostAddress();
// 局域网与广域网IP才认为合理,否则就认为不可用
if (ia.isSiteLocalAddress()) {
// 判断出当前是否为局域网IP,局域网也是合理的
TlogUtils.d(tag, "isSiteLocalAddress:" + ip);
return new NameAndIp(name, ip);
} else if (ia.isLoopbackAddress()) {
TlogUtils.d(tag, "isLoopbackAddress:" + ip);
} else if (ia.isAnyLocalAddress()) {
TlogUtils.d(tag, "isAnyLocalAddress:" + ip);
} else if (ia.isLinkLocalAddress()) {
TlogUtils.d(tag, "isLinkLocalAddress:" + ip);
} else if (ia.isMulticastAddress()) {
TlogUtils.d(tag, "isMulticastAddress:" + ip);
} else if (ia.isMCGlobal()) {
TlogUtils.d(tag, "isMCGlobal:" + ip);
} else if (ia.isMCLinkLocal()) {
TlogUtils.d(tag, "isMCLinkLocal:" + ip);
} else if (ia.isMCNodeLocal()) {
TlogUtils.d(tag, "isMCNodeLocal:" + ip);
} else if (ia.isMCOrgLocal()) {
TlogUtils.d(tag, "isMCOrgLocal:" + ip);
} else if (ia.isMCSiteLocal()) {
TlogUtils.d(tag, "isMCSiteLocal:" + ip);
} else {
// 能走到这里,说明是个普通的广域网IP
TlogUtils.d(tag, "普通ip:" + ip);
return new NameAndIp(name, ip);
}
}
}
} catch (Throwable e) {
e.printStackTrace();
}
return null;
}
}
让libcurl绑定网卡：
curl_easy_setopt(dlcurl->curl, CURLOPT_INTERFACE, "name");
得到错误日志：
2020-08-26 20:00:40.660 4103-8729/com.phone I/DownloadNative.v2: YKCLog_v2: XNDczNDUwMDIwOA==-2 ->[ |name= |videoRetry=0 |retryTime=2 |reqUrl=http://vali.cp31.ott.cibntv.net/67756D6080932713CFC02204E/03000500005F057E4E8BB780000000B94C56DC-0A70-4635-B35C-3E5A291ECB30-00002.ts?ccode=01010201&duration=2700&expire=18000&psid=9bc52504cc5c194fcd8a64f56679022c428e5&ups_client_netip=6a0b29dc&ups_ts=1598443186&ups_userid=1340295651&utid=XvD8%2BJtNHPkDAIaQEYw6XqaA&vid=XNDczNDUwMDIwOA%3D%3D&sm=1&operate_type=1&dre=u30&si=76&eo=0&dst=1&iv=1&s=bcecd0971b7f4e449eea&type=flvhdv3&bc=2&hotvt=1&rid=20000000163E8ED36726AEE7B2825AE912CC906B02000000&vkey=B9f5937585ebfe0e1f40685ecb4039c79&f=vali |finalPath=http://vali.cp31.ott.cibntv.net/67756D6080932713CFC02204E/03000500005F057E4E8BB780000000B94C56DC-0A70-4635-B35C-3E5A291ECB30-00002.ts?ccode=01010201&duration=2700&expire=18000&psid=9bc52504cc5c194fcd8a64f56679022c428e5&ups_client_netip=6a0b29dc&ups_ts=1598443186&ups_userid=1340295651&utid=XvD8%2BJtNHPkDAIaQEYw6XqaA&vid=XNDczNDUwMDIwOA%3D%3D&sm=1&operate_type=1&dre=u30&si=76&eo=0&dst=1&iv=1&s=bcecd0971b7f4e449eea&type=flvhdv3&bc=2&hotvt=1&rid=20000000163E8ED36726AEE7B2825AE912CC906B02000000&vkey=B9f5937585ebfe0e1f40685ecb4039c79&f=vali |savePath=/storage/emulated/0/Android/data/com.phone/files/offlinedata/XNDczNDUwMDIwOA==/2 |finalIpUrl= |repCode=7 |httpCode=0 |io_error:code=0desc:Success |retryType=0 |proxyUrl= |ipIndex=1 ip=113.142.161.248 isHttpIp1 |segSize=1119916 |curSpeed=-1 |contentLen=-1 |downloadLen=0 |contentType= |fileSize=0 |ioErrorDesc= |redirectUrls= |curlInfo= => Hostname 'vali.cp31.ott.cibntv.net' was found in DNS cache
=> Trying 202.108.249.185...
=> TCP_NODELAY set
=> Local Interface rmnet_data0 is ip 10.229.85.126 using address family 2
=> SO_BINDTODEVICE rmnet_data0 failed with errno 1: Operation not permitted; will do regular bind
=> Local port: 0
=> After 5948ms connect time, move on!
=> connect to 202.108.249.185 port 80 failed: Connection timed out
=> Trying 202.108.249.186...
=> TCP_NODELAY set
=> Local Interface rmnet_data0 is ip 10.229.85.126 using address family 2
=> SO_BINDTODEVICE rmnet_data0 failed with errno 1: Operation not permitted; will do regular bind
=> Local port: 0
=> After 2915ms connect time, move on!
=> connect to 202.108.249.186 port 80 failed: Connection timed out
=> Failed to connect to vali.cp31.ott.cibntv.net port 80: Connection timed out
=> Closing connection 21
]
这个方案，在iOS系统上，其实是可以正常。但是Android系统存在的权限管理问题，导致C++的libcurl报错。
我们查看curl的源码介绍，并没有找到有效的解决方案
#ifdef SO_BINDTODEVICE
/* I am not sure any other OSs than Linux that provide this feature,
* and at the least I cannot test. --Ben
*
* This feature allows one to tightly bind the local socket to a
* particular interface. This will force even requests to other
* local interfaces to go out the external interface.
*
*
* Only bind to the interface when specified as interface, not just
* as a hostname or ip address.
*
* interface might be a VRF, eg: vrf-blue, which means it cannot be
* converted to an IP address and would fail Curl_if2ip. Simply try
* to use it straight away.
*/
if(setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,
dev, (curl_socklen_t)strlen(dev) + 1) == 0) {
/* This is typically "errno 1, error: Operation not permitted" if
* you're not running as root or another suitable privileged
* user.
* If it succeeds it means the parameter was a valid interface and
* not an IP address. Return immediately.
*/
return CURLE_OK;
}
#endif
透传socket方案：
java层申请打开蜂窝通道，创建一个socket，将socket透传给C++
void openDoubleChanel() {
TlogUtils.d(TAG, "4g通道,尝试开启");
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
final ConnectivityManager connectivityManager = (ConnectivityManager) getApplication().getSystemService(CONNECTIVITY_SERVICE);
NetworkRequest request = new NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
connectivityManager.requestNetwork(request, new NetworkCallbackImpl(connectivityManager));
}
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public static class NetworkCallbackImpl extends ConnectivityManager.NetworkCallback {
final ConnectivityManager connectivityManager;
public NetworkCallbackImpl(ConnectivityManager connectivityManager) {
this.connectivityManager = connectivityManager;
}
@Override
public void onAvailable(Network network) {
TlogUtils.d(TAG, "4g通道,已经开启");
// 不要测百度，百度不支持IPv6，但是可以测m.baidu.com
String url = "http://valipl.cp31.ott.cibntv.net/6975030867335716092826D8B/03000300005F56527AB06EB7961451D178FC12-4CD4-44A7-A033-FAE171DF26A0.m3u8?ccode=01010101&duration=5374&expire=18000&psid=851c388bd1f8fc9a0aa11888f95b2854434af&ups_client_netip=2f580582&ups_ts=1599658512&ups_userid=1340295651&utid=XvD8%2BJtNHPkDAIaQEYw6XqaA&vid=XNDgwODE0NDc0MA&vkey=Bfcc9d9a459df2c6a97c2df3e223e65df&sm=1&operate_type=1&dre=u33&si=75&eo=0&dst=1&iv=1&s=aedc187a7603482190d5&type=3gphdv3&bc=2&rid=20000000DB5093085DD73D72365407F5E57F9FBE02000000";//hostEt.getText().toString();
try {
URL url1 = new URL(url);
int port = url1.getPort();
if (port <= -1) {
port = url1.getDefaultPort();
}
SocketFactory socketFactory = network.getSocketFactory();
//java 层创建好socket并绑好
final Socket socket = socketFactory.createSocket(url1.getHost(), port);
InetSocketAddress socketAddress = (InetSocketAddress) socket.getRemoteSocketAddress();
Log.e(TAG, "java层解析到的ip: " + socketAddress);
final ParcelFileDescriptor parcelFileDescriptor = ParcelFileDescriptor.fromSocket(socket);
// 开启C++
IYKCache.testSocket(parcelFileDescriptor.getFd(), url, new SocketOptionImpl(connectivityManager, this, socket, parcelFileDescriptor));
} catch (IOException e) {
e.printStackTrace();
}
}
}
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
private static class SocketOptionImpl implements SocketOption {
private final ConnectivityManager connectivityManager;
private final NetworkCallbackImpl networkCallback;
private final Socket socket;
private final ParcelFileDescriptor parcelFileDescriptor;
public SocketOptionImpl(ConnectivityManager connectivityManager, NetworkCallbackImpl networkCallback, Socket socket, ParcelFileDescriptor parcelFileDescriptor) {
this.connectivityManager = connectivityManager;
this.networkCallback = networkCallback;
this.socket = socket;
this.parcelFileDescriptor = parcelFileDescriptor;
}
// 关闭socket
@Override
public void closeSocket() {
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
parcelFileDescriptor.detachFd();
try {
parcelFileDescriptor.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 关闭双通
@Override
public void closeDoubleChanel() {
connectivityManager.unregisterNetworkCallback(networkCallback);
}
}
对应的C++层发起请求，请求结束后关闭socket，关闭4G通道
#include
#include
#include
#include
#include
#ifdef WIN32
#include
#include
#include
#define close closesocket
#else
#include
#include
#include
#include
#include
#endif
std::string resStr;
static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream) {
resStr += std::string((char *) ptr, size * nmemb);
return size * nmemb;
}
static curl_socket_t
opensocket(void *clientp, curlsocktype purpose, struct curl_sockaddr *address) {
curl_socket_t sockfd;
(void) purpose;
(void) address;
sockfd = *(curl_socket_t *) clientp;
/* the actual externally set socket is passed in via the OPENSOCKETDATA
option */
flash_util::log::d("双通道", std::string("opensocket"));
return sockfd;
}
static int closecb(void *clientp, curl_socket_t item) {
(void) clientp;
printf("libcurl wants to close %d now\n", (int) item);
return 0;
}
std::string errStr;
static int
dl_curl_debug_cb(CURL *handle, curl_infotype type, char *data, size_t size, void *userp) {
errStr += std::string((char *) data, size);
return 0;
}
static int sockopt_callback(void *clientp, curl_socket_t curlfd,
curlsocktype purpose) {
(void) clientp;
(void) curlfd;
(void) purpose;
/* This return code was added in libcurl 7.21.5 */
return CURL_SOCKOPT_ALREADY_CONNECTED;
}
extern "C"
JNIEXPORT void JNICALL
Java_com_flash_downloader_jni_FlashDownloaderJni_testSocket(JNIEnv *env, jclass clazz,
jint sockfd,
jstring urlJ,
jobject socket_optionJ) {
CURL *curl = curl_easy_init();
const std::string &url = parseJStringAndDeleteRef(env, urlJ);
curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
/* no progress meter please */
curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
/* send all data to this function */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
/* call this function to get a socket */
curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, dl_curl_debug_cb);
// curl_easy_setopt(curl, CURLOPT_DEBUGDATA, dlcurl);
/* call this function to close sockets */
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closecb);
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &sockfd);
/* call this function to set options for the socket */
curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
// curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
flash_util::log::d("双通道", "begin");
resStr = "";
errStr = "";
CURLcode resCode = curl_easy_perform(curl);
char *ip;
curl_easy_getinfo(curl, CURLINFO_PRIMARY_IP, &(ip));
close(sockfd);
//回调java层关闭fd引用
env->CallVoidMethod(socket_optionJ, env->GetMethodID(env->GetObjectClass(socket_optionJ), "closeSocket", "()V"));
//回调java层关闭双通
env->CallVoidMethod(socket_optionJ, env->GetMethodID(env->GetObjectClass(socket_optionJ), "closeDoubleChanel", "()V"));
curl_easy_cleanup(curl);
flash_util::log::d("双通道",
"code:" + std::to_string(resCode) + " ip:" + ip + "\nresStr:" + resStr + "\nerrStr:" + errStr);
}
成功发起请求，且IP为IPv6类型，当前设备仅蜂窝网才有IPv6，所以说明流量走了蜂窝网。
2020-09-10 12:06:51.377 31409-31409/com.phone D/YKDownload.双通道: 4g通道,尝试开启
2020-09-10 12:06:52.085 31409-31557/com.phone D/YKDownload.双通道: 4g通道,已经开启
2020-09-10 12:06:52.471 31409-31557/com.phone E/双通道: java层解析到的ip: valipl.cp31.ott.cibntv.net/2408:871a:1001:51ff::ff53:80
2020-09-10 12:06:53.282 31409-31557/com.phone D/DownloadNative.双通道: begin
2020-09-10 12:06:53.349 31409-31557/com.phone D/DownloadNative.双通道: opensocket
2020-09-10 12:06:53.400 31409-31557/com.phone D/DownloadNative.双通道: code:0 ip:2408:871a:1001:51ff::ff53
resStr:
403 Forbidden
403 Forbidden
openresty
errStr: Trying 101.227.24.225...
TCP_NODELAY set
Connected to valipl.cp31.ott.cibntv.net (2408:871a:1001:51ff::ff53) port 80 (#0)
GET /6975030867335716092826D8B/03000300005F56527AB06EB7961451D178FC12-4CD4-44A7-A033-FAE171DF26A0.m3u8?ccode=01010101&duration=5374&expire=18000&psid=851c388bd1f8fc9a0aa11888f95b2854434af&ups_client_netip=2f580582&ups_ts=1599658512&ups_userid=1340295651&utid=XvD8%2BJtNHPkDAIaQEYw6XqaA&vid=XNDgwODE0NDc0MA&vkey=Bfcc9d9a459df2c6a97c2df3e223e65df&sm=1&operate_type=1&dre=u33&si=75&eo=0&dst=1&iv=1&s=aedc187a7603482190d5&type=3gphdv3&bc=2&rid=20000000DB5093085DD73D72365407F5E57F9FBE02000000 HTTP/1.1
Host: valipl.cp31.ott.cibntv.net
Accept: */*
HTTP/1.1 403 Forbidden
Date: Thu, 10 Sep 2020 04:06:52 GMT
Content-Type: text/html
Content-Length: 166
Connection: keep-alive
anti-detail-code: 403611
Access-Control-Allow-Origin: *
Access-Control-Expose-Headers: Content-Length
cloud_type: aliyun
Server: Tengine
403 Forbidden
403 Forbidden
openresty
Curl_http_done: called premature == 0
Connection #0 to host valipl.cp31.ott.cibntv.net left intact