简介

使用socket函数创建套接字，并与uv_udp_t关联，可以实现对icmp包的发送和接收，实现类似ping命令的功能。

uv_loop_t* loop = uv_default_loop();	uv_udp_t* pUdp = new uv_udp_t;	int sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);    uv_udp_init(loop, pUdp);    uv_udp_open(pUdp, sock);

源码

学习icmp协议和libuv关于udp，定时器的使用。

创建了ICMP的套接字，并与uv_udp_t关联
创建一个定时器，并与uv_udp_t关联，用于处理响应超时
构造并发送一个icmp包req
收到icmp包rsp，打印响应内容，关闭定时器，关闭uv_udp_t句柄
超时未收到rsp，打印超时，关闭uv_udp_t句柄，关闭定时器

需要注意的是：由于套接字协议是IPPROTO_ICMP，收到的包是包含IP头的。

///*在入口函数中包含 _CrtDumpMemoryLeaks();  即可检测到内存泄露*/#define CRTDBG_MAP_ALLOC  #include 
   
      #include 
    
       ////#include 
     
          //for kbhit()#include "stdafx.h"#include "uv.h"#pragma pack(1)#define ICMP_ECHOREPLY  0#define ICMP_ECHOREQ    8#define REQ_DATASIZE    32     // Echo 请求数据的大小// IP Header -- RFC 791typedef struct tagIPHDR{
       u_char      VIHL;          // Version and IHL    u_char      TOS;           // Type Of Service    short       TotLen;        // Total Length    short       ID;            // Identification    short       FlagOff;       // Flags and Fragment Offset    u_char      TTL;           // Time To Live    u_char      Protocol;      // Protocol    u_short     Checksum;      // Checksum    struct    in_addr iaSrc;   // Internet Address - Source    struct    in_addr iaDst;   // Internet Address - Destination}IPHDR, *PIPHDR;// ICMP Header - RFC 792typedef struct tagICMPHDR{
       u_char    Type;            // Type    u_char    Code;            // Code    u_short   Checksum;        // Checksum    u_short   ID;              // Identification    u_short   Seq;             // Sequence    char      Data;            // Data}ICMPHDR, *PICMPHDR;// ICMP Echo Requesttypedef struct tagECHOREQUEST{
       ICMPHDR   icmpHdr;    uint64_t  dwTime;    char      cData[REQ_DATASIZE];}ECHOREQUEST, *PECHOREQUEST;// ICMP Echo Replytypedef struct tagECHOREPLY{
       IPHDR           ipHdr;    ECHOREQUEST     echoRequest;    char            cFiller[256];}ECHOREPLY, *PECHOREPLY;#pragma pack()//目的ipstruct sockaddr_in g_saDest;//icmp校验u_short in_cksum(u_short *addr, int len){
       register int nleft = len;    register u_short *w = addr;    register u_short answer;    register int sum = 0;    while( nleft > 1 )  {
           sum += *w++;        nleft -= 2;    }    if( nleft == 1 ) {
           u_short    u = 0;        *(u_char *)(&u) = *(u_char *)w ;        sum += u;    }    sum = (sum >> 16) + (sum & 0xffff);        sum += (sum >> 16);                answer = ~sum;                    return (answer);}void CreateIcmp(char* buff, ULONG* size){
       ECHOREQUEST echoReq;    static int nId = 1;    static int nSeq = 1;    int nRet;    //构造请求    echoReq.icmpHdr.Type        = ICMP_ECHOREQ;    echoReq.icmpHdr.Code        = 0;    echoReq.icmpHdr.Checksum    = 0;    echoReq.icmpHdr.ID          = nId++;    echoReq.icmpHdr.Seq         = nSeq++;    for (nRet = 0; nRet < REQ_DATASIZE; nRet++)        echoReq.cData[nRet] = ' '+nRet;    //保存发送时间    echoReq.dwTime              = uv_hrtime();    echoReq.icmpHdr.Checksum    = in_cksum((u_short *)&echoReq, sizeof(ECHOREQUEST));        memcpy(buff, &echoReq, sizeof(ECHOREQUEST));    *size = sizeof(ECHOREQUEST);}static void slab_alloc(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
       /* up to 16 datagrams at once */    static char slab[16 * 64 * 1024];    buf->base = slab;    buf->len = sizeof(slab);}static void on_recv(uv_udp_t* handle, ssize_t nread, const uv_buf_t* rcvbuf, const struct sockaddr* addr, unsigned flags) {
       ECHOREPLY* r = (ECHOREPLY*)rcvbuf->base;    struct sockaddr_in* ad = (struct sockaddr_in*)addr;    uv_timer_t* pTimer = (uv_timer_t*)handle->data;    char ip[64] = {
   0};    uv_ip4_name(ad, ip, sizeof(ip));    if (nread == 0) {
           /* Everything OK, but nothing read. */        return;    }    if (memcmp(&g_saDest.sin_addr, &ad->sin_addr, sizeof(ad->sin_addr)) != 0)    {
           return;    }    uint64_t now = uv_hrtime();    uint64_t time = now - (r->echoRequest.dwTime);    double   dtime = time / 1000000.0 ;    printf("%d bytes form %s: icmp_seq=%d ttl=%d time=%.3f ms\n",     	sizeof(ECHOREQUEST) - sizeof(ICMPHDR), ip, (r->echoRequest.icmpHdr.Seq), r->ipHdr.TTL, dtime);        //停止定时器，关闭定时器句柄    if(pTimer)    {
           uv_timer_stop(pTimer);        uv_close((uv_handle_t*)pTimer, NULL);    }	//停止udp的接收，关闭udp句柄    uv_udp_recv_stop(handle);    uv_close((uv_handle_t*)handle, NULL);}static void on_send(uv_udp_send_t* req, int status) {
       uv_buf_t *buf = (uv_buf_t *)req->data;	//发送完毕释放内存    delete [] buf->base;    delete buf;    delete req;}void timercb(uv_timer_t* req){
       uv_udp_t* handle = (uv_udp_t*)req->data;    //停止udp的接收，关闭udp句柄    uv_udp_recv_stop(handle);    uv_close((uv_handle_t*)handle, NULL);    printf("timeout\n");        //停止定时器，关闭定时器句柄    uv_timer_stop(req);    uv_close((uv_handle_t*)req, NULL);}int _tmain(int argc, _TCHAR* argv[]){
   	//libuv环境初始化，内存分配    uv_loop_t* loop = uv_default_loop();    uv_udp_t* pUdp = new uv_udp_t;    uv_timer_t* pTimer = new uv_timer_t;    uv_udp_send_t *reqSend = new uv_udp_send_t;        //设置ping的目的地址    const char* strDstIp = "192.168.10.1";    uv_ip4_addr(strDstIp, 0, &g_saDest);        	//创建发送数据的buf    uv_buf_t *buf = new uv_buf_t;    buf->base = new char[sizeof(ECHOREQUEST)] ;    buf->len  = sizeof(ECHOREQUEST);    	//创建套接字，设置关联    int sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);    uv_udp_init(loop, pUdp);    uv_udp_open(pUdp, sock);	//初始化定时器，做简单的数据关联，以便后续管理    uv_timer_init(loop, pTimer);    pTimer->data = pUdp;    pUdp->data   = pTimer;    reqSend->data = buf;	//构造icmp请求报文    CreateIcmp(buf->base, &buf->len);    printf("ping %s:\n", strDstIp);	//发送icmp报文，启动udp接收，启动1s超时的定时器    uv_udp_send(reqSend, pUdp, buf, 1, (const sockaddr*)&g_saDest, on_send);    uv_udp_recv_start(pUdp, slab_alloc, on_recv);    uv_timer_start(pTimer, timercb, 1000, 0);    uv_run(loop, UV_RUN_DEFAULT);	//超时或收到响应后退出释放内存    delete pUdp;    delete pTimer;	//关闭loop    printf("uv_loop_close ...\n");    uv_loop_close(loop);    _CrtDumpMemoryLeaks();    getchar();    return 0;}