#ICMP
如何使用NDK实现ICMP Ping功能
要使用NDK实现ICMP Ping功能，您需要使用C或C++编写代码，并使用NDK提供的库。以下是实现ICMP Ping功能的步骤：
1. 包含必要的头文件。
```c
#include<stdio.h>
#include <stdlib.h>
#include<string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <time.h>
#include <errno.h>
```
2. 定义ICMP数据包结构。
```c
typedef struct {
struct icmphdr hdr;
unsigned char data[64 - sizeof(struct icmphdr)];
} icmp_packet_t;
```
3. 创建一个发送ICMP数据包的函数。
```c
void send_icmp_packet(int sockfd, struct sockaddr_in *dst_addr, icmp_packet_t *packet, int seq) {
packet->hdr.type = ICMP_ECHO;
packet->hdr.code = 0;
packet->hdr.un.echo.id = htons(getpid());
packet->hdr.un.echo.sequence = htons(seq);
packet->hdr.checksum = 0;
packet->hdr.checksum = in_cksum((unsigned short *)packet, sizeof(*packet));
sendto(sockfd, packet, sizeof(*packet), 0, (struct sockaddr *)dst_addr, sizeof(*dst_addr));
}
```
4. 创建一个接收ICMP数据包的函数。
```c
int receive_icmp_packet(int sockfd, icmp_packet_t *packet, struct sockaddr_in *src_addr) {
socklen_t src_addr_len = sizeof(*src_addr);
int recv_len = recvfrom(sockfd, packet, sizeof(*packet), 0, (struct sockaddr *)src_addr, &src_addr_len);
if (recv_len < 0) {
return -1;
}
if (packet->hdr.type == ICMP_ECHOREPLY && packet->hdr.un.echo.id == htons(getpid())) {
return 0;
}
return -1;
}
```
5. 在主函数中创建一个循环，发送ICMP数据包并接收响应。
```c
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("Usage: %s<hostname>\n", argv[0]);
return 1;
}
struct hostent *host = gethostbyname(argv[1]);
if (!host) {
perror("gethostbyname");
return 1;
}
struct sockaddr_in dst_addr;
memset(&dst_addr, 0, sizeof(dst_addr));
dst_addr.sin_family = AF_INET;
memcpy(&dst_addr.sin_addr, host->h_addr, host->h_length);
int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (sockfd < 0) {
perror("socket");
return 1;
}
icmp_packet_t packet;
int seq = 0;
while (1) {
send_icmp_packet(sockfd, &dst_addr, &packet, seq);
seq++;
struct timeval timeout;
timeout.tv_sec = 1;
timeout.tv_usec = 0;
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
struct sockaddr_in src_addr;
int ret = receive_icmp_packet(sockfd, &packet, &src_addr);
if (ret == 0) {
printf("Ping %s: seq=%d, time=%.3f ms\n", argv[1], seq, 1.0);
} else {
printf("Request timed out\n");
}
usleep(1000000);
}
close(sockfd);
return 0;
}
```
6. 使用NDK编译代码。
在Android.mk文件中添加以下内容：
```makefile
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := ping
LOCAL_SRC_FILES := ping.c
LOCAL_LDLIBS := -llog
include $(BUILD_EXECUTABLE)
```
然后运行`ndk-build`命令进行编译。
7. 将编译好的可执行文件推送到Android设备上，并使用adb shell运行。
这样，您就可以使用NDK实现ICMP Ping功能了。... 展开详请
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