android接入traceroute in cpp by api

要在 Android 应用程序中使用 C++ 实现 traceroute，可以使用以下步骤：

1. 创建一个 C++ 类，该类将实现 traceroute 功能。这个类可以使用第三方库，如 libnet、libpcap 和 libtrace，来实现 traceroute。

2. 将 C++ 代码编译成共享库（.so 文件）。

3. 在你的 Android 项目中添加共享库文件。

4. 在 Java 代码中调用 C++ 的 traceroute 方法。

以下是一个简单的示例：

1. 创建一个名为 Traceroute 的 C++ 类，该类将实现 traceroute 功能。

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/ip_icmp.h>
#include <sys/types.h>
#include <time.h>

#define PACKETSIZE 64

class Traceroute {
public:
    Traceroute(const char* hostname);
    ~Traceroute();
    void run();
private:
    const char* mHostname;
    int mTtl;
    int mSocket;
    struct sockaddr_in mDestAddr;
    char* mPacket;
    struct timeval mTimeout;
    fd_set mReadSet;
    struct timeval mStartTime;
    struct timeval mEndTime;
    struct timeval mTimeDiff;
    void sendPacket(int ttl);
    int receivePacket(int ttl);
    void printAddress(struct sockaddr_in addr);
};

2. 实现 Traceroute 类的构造函数和析构函数。

Traceroute::Traceroute(const char* hostname) {
    mHostname = hostname;
    mTtl = 1;
    mSocket = -1;
    mPacket = NULL;
    memset(&mDestAddr, 0, sizeof(struct sockaddr_in));
    memset(&mTimeout, 0, sizeof(struct timeval));
    memset(&mReadSet, 0, sizeof(fd_set));
    memset(&mStartTime, 0, sizeof(struct timeval));
    memset(&mEndTime, 0, sizeof(struct timeval));
    memset(&mTimeDiff, 0, sizeof(struct timeval));
}

Traceroute::~Traceroute() {
    if (mSocket != -1) {
        close(mSocket);
    }
    if (mPacket != NULL) {
        free(mPacket);
    }
}

3. 实现 Traceroute 类的 run 方法，该方法将实现 traceroute 功能。

void Traceroute::run() {
    struct hostent* host;
    struct timeval timeout;
    int maxfd;
    int ret;
    int done = 0;

    // resolve hostname
    host = gethostbyname(mHostname);
    if (host == NULL) {
        printf("traceroute: unknown host %s\n", mHostname);
        return;
    }

    // create socket
    mSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
    if (mSocket < 0) {
        printf("traceroute: cannot create socket: %s\n", strerror(errno));
        return;
    }

    // set socket options
    setsockopt(mSocket, IPPROTO_IP, IP_TTL, &mTtl, sizeof(mTtl));

    // set destination address
    mDestAddr.sin_family = AF_INET;
    mDestAddr.sin_port = 0;
    memcpy(&mDestAddr.sin_addr, host->h_addr, host->h_length);

    // allocate packet buffer
    mPacket = (char*)malloc(PACKETSIZE);
    if (mPacket == NULL) {
        printf("traceroute: out of memory\n");
        return;
    }

    // set timeout
    timeout.tv_sec = 1;
    timeout.tv_usec = 0;

    // loop until done
    while (!done) {
        // send packet
        sendPacket(mTtl);

        // receive packet
        ret = receivePacket(mTtl);
        if (ret == 0) {
            // reached destination
            done = 1;
        } else if (ret == -1) {
            // error
            printf("traceroute: error receiving packet: %s\n", strerror(errno));
            return;
        } else {
            // continue
        }

        // increase ttl
        mTtl++;

        // check if max ttl reached
        if (mTtl > 30) {
            printf("traceroute: max ttl reached\n");
            break;
        }
    }
}

4. 实现 Traceroute 类的 sendPacket 和 receivePacket 方法。

void Traceroute::sendPacket(int ttl) {
    struct icmp* icmp;
    int len;

    // set packet data
    icmp = (struct icmp*)mPacket;
    icmp->icmp_type = ICMP_ECHO;
    icmp->icmp_code = 0;
    icmp->icmp_id = getpid();
    icmp->icmp_seq = ttl;
    memset(icmp->icmp_data, 0xa5, PACKETSIZE - sizeof(struct icmp));

    // set packet length
    len = sizeof(struct icmp) + PACKETSIZE - sizeof(struct icmp);

    // send packet
    gettimeofday(&mStartTime, NULL);
    if (sendto(mSocket, mPacket, len, 0, (struct sockaddr*)&mDestAddr, sizeof(struct sockaddr_in)) <= 0) {
        printf("traceroute: error sending packet: %s\n", strerror(errno));
        return;
    }
}

int Traceroute::receivePacket(int ttl) {
    struct sockaddr_in addr;
    socklen_t addrlen;
    struct ip* ip;
    struct icmp* icmp;
    int len;
    int ret;

    // set timeout
    mTimeout.tv_sec = 1;
    mTimeout.tv_usec = 0;

    // clear read set
    FD_ZERO(&mReadSet);
    FD_SET(mSocket, &mReadSet);

    // select
    ret = select(mSocket + 1, &mReadSet, NULL, NULL, &mTimeout);
    if (ret == 0) {
        // timeout
        printf("%2d  * *\n", ttl);
        return 1;
    } else if (ret < 0) {
        // error
        return -1;
    }

    // receive packet
    addrlen = sizeof(struct sockaddr_in);
    len = recvfrom(mSocket, mPacket, PACKETSIZE, 0, (struct sockaddr*)&addr, &addrlen);
    if (len < 0) {
        printf("traceroute: error receiving packet: %s\n", strerror(errno));
        return -1;
    }

    // check packet length
    ip = (struct ip*)mPacket;
    if (len < (int)(ip->ip_hl * 4 + sizeof(struct icmp))) {
        printf("traceroute: packet too short\n");
        return -1;
    }

    // check packet type
    icmp = (struct icmp*)(mPacket + ip->ip_hl * 4);
    if (icmp->icmp_type == ICMP_ECHOREPLY) {
        // received reply
        gettimeofday(&mEndTime, NULL);
        timersub(&mEndTime, &mStartTime, &mTimeDiff);
        printf("%2d  ", ttl);
        printAddress(addr);
        printf("  %.3f ms\n", mTimeDiff.tv_sec * 1000.0 + mTimeDiff.tv_usec / 1000.0);
        return 0;
    } else if (icmp->icmp_type == ICMP_TIME_EXCEEDED) {
        // received time exceeded
        printf("%2d  ", ttl);
        printAddress(addr);
        printf("  *\n");
        return 1;
    } else {
        // received unknown packet
        printf("traceroute: unknown packet type: %d\n", icmp->icmp_type);
        return -1;
    }
}

5. 在 Java 代码中调用 C++ 的 traceroute 方法。

public class MainActivity extends AppCompatActivity {
    static {
        System.loadLibrary("traceroute");
    }

    private static final String HOSTNAME = "www.google.com";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Traceroute traceroute = new Traceroute(HOSTNAME);
        traceroute.run();
    }
}

注意，为了在 Android 应用程序中使用 C++，需要使用 Android NDK。在你的 Android 项目中添加一个名为 jni 的文件夹，并在其中创建一个名为 Android.mk 的文件和一个名为 traceroute.cpp 的文件。Android.mk 文件应该包含以下内容：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := traceroute
LOCAL_SRC_FILES := traceroute.cpp

include $(BUILD_SHARED_LIBRARY)

然后，可以使用 ndk-build 命令编译 C++ 代码，并将生成的共享库文件添加到 Android 项目中。