数据链接响应

sp<RILRequest> RIL::processSolicited(const Parcel& p) {
    switch (rr->mRequest) {
        case RIL_REQUEST_SETUP_DATA_CALL:
                ret =  responseSetupDataCall(p);
                break;
    }

    …....

       } else {
            if (rr->mResult != NULL) {
                AsyncResult::forMessage(rr->mResult, ret, NULL);
                rr->mResult->sendToTarget();
            }
        }
}

sp<Object> RIL::responseSetupDataCall(const Parcel & p) {
    dataCall = getDataCallResponse(p, ver);
    return dataCall;
}

sp<DataCallResponse> RIL::getDataCallResponse(const Parcel & p, int32_t version) {
      dataCall->status = p.readInt32();
            dataCall->suggestedRetryTime = p.readInt32();
            dataCall->cid = p.readInt32();
            dataCall->active = p.readInt32();
            dataCall->type = readString(p);
            dataCall->ifname = readString(p);
            sp<String> addresses = readString(p);
            sp<String> dnses = readString(p);
            sp<String> gateways = readString(p);

            return dataCall;
}

bool DataConnection::DcActivatingState::processMessage(const sp<Message>& msg) {
    switch (msg->what) {
        case EVENT_SETUP_DATA_CONNECTION_DONE: {
        DataCallResponse::SetupResult result = pDC->onSetupConnectionCompleted(ar);
            switch (result.getValue()) {
                    case DataCallResponse::SetupResult::SUCCESS: {
                    pDC->mDcFailCause = DcFailCause::NONE;
                    pDC->transitionTo(pDC->mActiveState);//状态机状态转化
                    break;
                }
        }
    }
}

DataCallResponse::SetupResult DataConnection::onSetupConnectionCompleted(const sp<AsyncResult>& ar) {
    result = updateLinkProperty(response)->setupResult;
}
sp<DataConnection::UpdateLinkPropertyResult> DataConnection::updateLinkProperty(const sp<DataCallResponse>& newState) {
    result->setupResult = setLinkProperties(newState, result->newLp);
}

void DataConnection::DcActiveState::enter() {
    pDC->notifyAllOfConnected(Phone::REASON_CONNECTED());
}

void DataConnection::notifyAllOfConnected(const android::sp<String>& reason) {
    notifyAllWithEvent(NULL, DctConstants::EVENT_DATA_SETUP_COMPLETE, reason);
}

void DcTrackerBase::handleMessage(const sp<Message>& msg) {
    switch (msg->what) {
          case DctConstants::EVENT_DATA_SETUP_COMPLETE:
        mCidActive = msg->arg1;
        onDataSetupComplete(safe_cast<AsyncResult*>(msg->obj));
        break;
    }
}

void DcTracker::onDataSetupComplete(const android::sp<AsyncResult>& ar) {
    apnContext->setState(DctConstants::State::CONNECTED);
}

void MobileDataStateReceiver::onReceive(const sp<Context>& context, const sp<Intent>& intent) {
    switch (state) {
        case PhoneConstants::DataState::CONNECTED:                  
            mdst->setDetailedState(NetworkInfo::DetailedState::CONNECTED, reason, apnName);
            break;
    }
}

void MobileDataStateTracker::setDetailedState(NetworkInfo::DetailedState state, const sp<String>& reason,const sp<String>& extraInfo) {
    sp<Message>msg=mTarget->obtainMessage(NetworkStateTracker::EVENT_STATE_CHANGED,new NetworkInfo(mNetworkInfo));
      msg->sendToTarget();
}

ConnectivityService.cpp

void ConnectivityService::MyHandler::handleMessage(const sp<Message>& msg) {
    if (msg->what == NetworkStateTracker::EVENT_STATE_CHANGED) {


        } else if (state == NetworkInfo::State::CONNECTED) { 
                             mConnectivityService->handleConnect(info); 
            } 
    }
}

void ConnectivityService::handleConnect(const sp<NetworkInfo>& info) {
    handleConnectivityChange(info, false);
}

void ConnectivityService::handleConnectivityChange(const sp<NetworkInfo>& replacedInfo, bool doReset) { 
        mNetIdtoInterfaces->put(ifa, new Integer(newNetId)); 
                mNetd->createPhysicalNetwork(newNetId); //binder到NetworkManagementService.cpp
                mNetd->addInterfaceToNetwork(ifa, newNetId);  //  1、 addInterfaceToNetwork 

        // 2、 updateRoutes
        bool resetDns = updateRoutes(newLp, curLp, (*mNetConfigs)[netType]->isDefault());
}

1、 addInterfaceToNetwork
NetworkManagementService.cpp

void NetworkManagementService::addInterfaceToNetwork(const android::sp<String> & iface, int netId) { 
    modifyInterfaceInNetwork(new String("add"), netId, iface); 
} 

void NetworkManagementService::modifyInterfaceInNetwork(const android::sp<String> & action, int netId, const android::sp<String> & iface) { 

    mConnector->doCommand(cmd, ret); 
}

NativeDaemonConnector.cpp

Vector<sp<String> > NativeDaemonConnector::doCommand(const sp<String>& cmd, int & ret) { 
    return doCommandLocked(cmd, ret); 
} 

Vector<sp<String> > NativeDaemonConnector::doCommandLocked(const sp<String>& cmd, int& ret) { 
    bool rc = sendCommandLocked(newCmd); 
}

bool NativeDaemonConnector::sendCommandLocked(const sp<String>& command) { 
    return sendCommandLocked(command, NULL); 
} 

bool NativeDaemonConnector::sendCommandLocked(const sp<String>& command, const sp<String>& argument) { 
     if (mOutputStream == NULL) { 
        return false; 
    } else { 
               mOutputStream->write(outCommand, 0, outCommand->length()); 
    } 
    return true; 
} 

socket(netd)
这个socket是在NetlinkManager中创建的
CommandListener.cpp

int CommandListener::NetworkCommand::runCommand(SocketClient* client, int argc, char** argv) { 
        if (!strcmp(argv[2], "add")) { 
            if (int ret = sNetCtrl->addInterfaceToNetwork(netId, argv[4])) { 
                return operationError(client, "addInterfaceToNetwork() failed", ret); 
            } 
        } else if (!strcmp(argv[2], "remove")) { 
            if (int ret = sNetCtrl->removeInterfaceFromNetwork(netId, argv[4])) { 
                return operationError(client, "removeInterfaceFromNetwork() failed", ret); 
            } 
        }   
}

NetworkController.cpp

int NetworkController::addInterfaceToNetwork(unsigned netId, const char* interface) { 
    RouteController::addInterfaceToLocalNetworkL(netId, interface); 

    return getNetworkLocked(netId)->addInterface(interface); 
} 

PhysicalNetwork.cpp

int PhysicalNetwork::addInterface(const std::string& interface) { 
     if (int ret = RouteController::addInterfaceToPhysicalNetwork(mNetId, interface.c_str(), 
                                                                 mPermission)) { 
        return ret; 
    } 
    return 0; 
} 

RouteController.cpp

int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface, 
                                                   Permission permission) { 
    if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) { 
        return ret; 
    } 
    updateTableNamesFile(); 
    return 0; 
} 

WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface, 
                                             Permission permission, bool add) { 
    uint32_t table = getRouteTableForInterface(interface); 
    if (table == RT_TABLE_UNSPEC) { 
        return -ESRCH; 
    } 

    if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) { 
        return ret; 
    } 
    if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID, add)) { 
        return ret; 
    } 
    if (int ret = modifyOutputInterfaceRule(interface, table, permission, INVALID_UID, INVALID_UID, add)) { 
        return ret; 
    } 
    return modifyImplicitNetworkRule(netId, table, permission, add); 
} 

WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table, 
                                                 Permission permission, uid_t uidStart, 
                                                 uid_t uidEnd, bool add) { 

    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table, fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd); 
} 

WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,uint32_t fwmark, uint32_t mask, const char* iif, const char* oif, uid_t uidStart, uid_t uidEnd) { 
    for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) { 
        rule.family = AF_FAMILIES[i]; 
        if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) { 
            return ret; 
        } 
    } 
}

 int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { 
    int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); 
    if (sock != -1 && 
            connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), 
                    sizeof(NETLINK_ADDRESS)) != -1 && 
            writev(sock, iov, iovlen) != -1 && 
            (ret = recv(sock, &response, sizeof(response), 0)) != -1) { 
        if (ret == sizeof(response)) { 
            ret = response.err.error;  // Netlink errors are negative errno. 
        }
}

2、 updateRoutes

ConnectivityService.cpp
bool ConnectivityService::updateRoutes(const sp<LinkProperties>& newLp, const sp<LinkProperties>& curLp, bool isLinkDefault) {
        if (isLinkDefault || !(r->isDefaultRoute())) { 
            addRoute(newLp, r, TO_DEFAULT_TABLE); 
        } else { 
            addRoute(newLp, r, TO_SECONDARY_TABLE); 
        } 
}

bool ConnectivityService::addRoute(const sp<LinkProperties>& p, const sp<RouteInfo>& r, 
                                   bool toDefaultTable) { 
    sp<String> pIfName = p->getInterfaceName(); 
    return  (pIfName, p, r, 0, ADD, toDefaultTable); 
} 

bool ConnectivityService::modifyRoute(const sp<String>& ifaceName, const sp<LinkProperties>& lp, const sp<RouteInfo>& r, int32_t cycleCount, bool doAdd, bool toDefaultTable) {

    if (r->getDestination() != NULL && r->getDestination()->getNetworkPrefixLength() == 32 && prefixLength != 32) { 
               sp<LinkAddress> l = new LinkAddress(r->getDestination()->getAddress(), prefixLength); 
               sp<RouteInfo> ri = new RouteInfo(l, r->getGateway()); 
               mAddedRoutes->add(ri); 
               mNetd->addRoute(ifaceName,netId, ri); 
           } else { 
               mAddedRoutes->add(r); 
               mNetd->addRoute(ifaceName,netId, r); 
           } 
}

void NetworkManagementService::addRoute(const android::sp<String> & ifname,int32_t netId, const sp<RouteInfo>& route) { 
    modifyRoute(ifname, netId, mADD, route, DEFAULT()); 
} 

void NetworkManagementService::modifyRoute(const android::sp<String> & ifname, int32_t netId, int32_t action, const sp<RouteInfo>& route, const sp<String>& type) {

    Vector<sp<String> > rsp = mConnector->doCommand(cmd->toString(), ret);
}

NativeDaemonConnector.cpp

Vector<sp<String> > NativeDaemonConnector::doCommand(const sp<String>& cmd, int & ret) { 
    return doCommandLocked(cmd, ret); 
} 

Vector<sp<String> > NativeDaemonConnector::doCommandLocked(const sp<String>& cmd, int& ret) { 
    bool rc = sendCommandLocked(newCmd); 
}

bool NativeDaemonConnector::sendCommandLocked(const sp<String>& command) { 
    return sendCommandLocked(command, NULL); 
} 

bool NativeDaemonConnector::sendCommandLocked(const sp<String>& command, const sp<String>& argument) { 
     if (mOutputStream == NULL) { 
        return false; 
    } else { 
               mOutputStream->write(outCommand, 0, outCommand->length()); 
    } 
    return true; 
} 

socket(netd)
这个socket是在NetlinkManager中创建的

CommandListener.cpp

int CommandListener::NetworkCommand::runCommand(SocketClient* client, int argc, char** argv) { 
         if (add) { 
            ret = sNetCtrl->addRoute(netId, interface, destination, nexthop, legacy, uid); 
        } else { 
            ret = sNetCtrl->removeRoute(netId, interface, destination, nexthop, legacy, uid); 
        } 
}

NetworkController.cpp
int NetworkController::addRoute(unsigned netId, const char* interface, const char* destination, 
                                const char* nexthop, bool legacy, uid_t uid) { 
    return modifyRoute(netId, interface, destination, nexthop, true, legacy, uid); 
} 

int NetworkController::modifyRoute(unsigned netId, const char* interface, const char* destination, 
                                   const char* nexthop, bool add, bool legacy, uid_t uid) { 
            if(add) { 
     RouteController::addRoute(interface, destination, nexthop, RouteController::LOCAL_NETWORK); 
            } else { 
                RouteController::removeRoute(interface, destination, nexthop, RouteController::LOCAL_NETWORK); 
            } 
}

RouteController.cpp

int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop, 
                              TableType tableType) { 
    return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType); 
}
int modifyRoute(uint16_t action, const char* interface, const char* destination, const char*                nexthop, RouteController::TableType tableType) { 
    int ret = modifyIpRoute(action, table, interface, destination, nexthop); 
    return 0; 
} 

int modifyIpRoute(uint16_t action, uint32_t table, const char* interface, 
                                     const char* destination, const char* nexthop) { 
    return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov));
}

 int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { 
    int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); 
    if (sock != -1 && 
            connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), 
                    sizeof(NETLINK_ADDRESS)) != -1 && 
            writev(sock, iov, iovlen) != -1 && 
            (ret = recv(sock, &response, sizeof(response), 0)) != -1) { 
        if (ret == sizeof(response)) { 
            ret = response.err.error;  // Netlink errors are negative errno. 
        }
}

注：socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); 套接字AF_NETLINK，则是用于与kernel通讯的接口。通过向量IO向kernel中发送 iov数据，并同时接收响应，错误处理。

NETD
Android5.0之后，网络的功能实现完全转移到netd上面，主要包括ip，路由配置，dns代理设置，带宽控制和流量统计等。
下面是Netd框架示意图，NetworkManagerService和NativeDeamonConnect是java代码，NetworkManagerService作为service随系统启动，java层所有对网络的操作都通过它来完成。
其他都是c++代码，主要完成两个工作：
1、接收上层的命令，完成指定对网络的操作；
2、接收kernel netlink信息，传递到上层。
接收上层命令的工作，通过4个socket完成：
/dev/socket/netd ————– CommandListener
/dev/socket/dnsproxyd ————– DnsproxyListener
/dev/socket/mdns –————– MdnsSdListener
/dev/socket/fwmarkd –————– FwmarkServer

CommandListener接收配置ip，路由，iptables的命令
DnsproxyListener接收查询dns的操作

MdnsSdListener接收针对mdnsd的操作

FwmarkServer用于对特定的socket设置mark值

下图是Netlink部分，模块调用关系示例NetlinkManager启动3个socket，用于监听3种不同的event：Uevent，RouteEvent，QuotaEvent。 通过SocketListener实现监听功能，netlink信息，最终通过/dev/socket/netd送到 NetworkManagementService(java代码)，分配到注册到它里面的各个观察者实例(Ethernet，wifi等)。