TCP协议学习记录 (二) Ping程序

简单的实现了一个ping程序,没有做icmp差错报文的检查。

支持自定义字节数,支持发包个数 

 

#pragma pack(4)

#define  ECHO_REQUEST        8
#define  DATASIZE            65500
#define  PACKETSIZE          65535

struct iphdr
{
    unsigned char  ip_hdr_len : 4; //包头长度
    unsigned char  ip_version : 4; //版本
    unsigned char  ip_tos;

    unsigned short ip_length;  //总长度
    unsigned short ip_identify;//标识
    unsigned short ip_offset;//片偏移
    unsigned char  ip_ttl;
    unsigned char  ip_protocol;
    unsigned short ip_cksum;

    struct in_addr ip_src; //源地址
    struct in_addr ip_dst; //目的地址
};

struct icmphdr
{
    unsigned char  icmp_type; //8位类型
    unsigned char  icmp_code; //8位代码
    unsigned short icmp_cksum; //16位的校验和

    unsigned short icmp_identify;
    unsigned short icmp_seq;
    
    LONGLONG       icmp_timestamp;
    char           icmp_data[DATASIZE];
};

unsigned short checksum(int count,unsigned short* addr)
{
    long sum = 0;

    while(count > 1)
    {
        sum   +=*addr++;
        count -= sizeof(unsigned short);
    }

    if(count > 0)
    {
        sum  +=*(unsigned char*)addr;
    }

    while(sum >> 16)
    {
        sum = (sum & 0xFFFF) + (sum >> 16);
    }
    
    return (unsigned short)(~sum);
}

void packet_pad(char * buf,int payload)
{
    char pad[] = "\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f\x70\x71\x7\x73\x74\x75\x76\x77";
    
    int size   = sizeof(pad) -1;
    int count  = payload / size;
    int remain = payload % size;
    int offset = 0; //偏移

    memset((void *)buf,0,payload);

    for(int i = 0;i < count; ++i)
    {
        memcpy((void *)(buf + offset),(void *)pad,size);
        offset += size;
    }

    memcpy((void *)(buf + offset),(void *)pad,remain);
}

LONGLONG getsystickcount64()
{
    static LARGE_INTEGER tickspersecond = {0};
    LARGE_INTEGER tick;

    if(!tickspersecond.QuadPart)
    {
        QueryPerformanceFrequency(&tickspersecond);
    }

    QueryPerformanceCounter(&tick);

    LONGLONG seconds     = tick.QuadPart / tickspersecond.QuadPart;
    LONGLONG leftPart    = tick.QuadPart - (tickspersecond.QuadPart * seconds);
    LONGLONG millseconds = ((leftpart << 10)  - ((leftpart << 4) + (leftpart << 3)))  / tickspersecond.QuadPart;
    LONGLONG ret         = ((seconds  << 10)  - ((seconds  << 4) + (seconds  << 3)))  + millseconds;

    return ret;
};

bool ping(char * target,int payload,int count)
{
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);

    SOCKET soc = socket(AF_INET,SOCK_RAW,IPPROTO_ICMP);
    if(soc == -1)
    {
        printf("create raw socket failed!\n");
        return false;
    }
    
    if(payload > DATASIZE)
    {
        printf("发送的字节数有错误,有效范围从 0 到 %d",DATASIZE);
        return false;
    }

    payload = payload - sizeof(LONGLONG); 

    struct sockaddr_in  addrsrv;

    addrsrv.sin_family        = AF_INET;
    addrsrv.sin_port          = htons(0);
    struct hostent* phostent  = gethostbyname(target);  
    if (phostent)  
    {  
        addrsrv.sin_addr.s_addr = *(u_long *)phostent->h_addr_list[0];
    }

    printf("正在 Ping %s [%s] 具有 %d 字节的数据: \n",target,inet_ntoa(addrsrv.sin_addr),payload + sizeof(LONGLONG));
    
    icmphdr ihdr       = {0};
    
    memset((void *)ihdr.icmp_data,0,DATASIZE);
    packet_pad(ihdr.icmp_data,payload); //填充数据
    
    ihdr.icmp_type        = ECHO_REQUEST;
    ihdr.icmp_identify    = (unsigned short)GetCurrentProcessId();
    
    int hdr_len           = payload + sizeof(icmphdr) - DATASIZE;

    struct timeval timeout; 
    struct sockaddr_in addrcli;

    char recv[PACKETSIZE]   = {0};

    unsigned long interval  = 0;
    unsigned long avgdelay  = 0;
    unsigned long maxdelay  = 0;
    unsigned long mindelay  = ~0;

    unsigned int  sndcnt = count;
    unsigned int  loscnt = 0;

    for(int seq = 0; seq < count; ++seq)
    {
        memset((void *)recv,0,PACKETSIZE);

        ihdr.icmp_seq        = seq;
        ihdr.icmp_cksum      = 0;
        ihdr.icmp_timestamp  = getsystickcount64(); //时间戳
        ihdr.icmp_cksum      = checksum(hdr_len,(unsigned short *)&ihdr);
        
        if(sendto(soc,(char *)&ihdr,hdr_len,0,(sockaddr *)&addrsrv,sizeof(addrsrv)) == -1)
        {
            --sndcnt;
            continue;
        }
        
        int  nlength    = sizeof(addrcli);
        timeout.tv_sec  = 3000;  
        timeout.tv_usec = 0;

        setsockopt(soc, SOL_SOCKET,SO_RCVTIMEO, (char*)&timeout,sizeof(timeout));

        if(recvfrom(soc,recv,PACKETSIZE,0,(sockaddr *)&addrcli,&nlength) == -1)
        {
            printf("请求超时!\n");
            ++loscnt;
            continue;
        }

        iphdr* piphdr = (iphdr *)recv;
        if(checksum(piphdr->ip_hdr_len << 2,(unsigned short *)piphdr) != 0)
        {
            printf("invalid ip packet!\n");
            continue;
        }

        icmphdr* pichdr = (icmphdr *)(piphdr + 1);
        if(checksum(hdr_len,(unsigned short *)pichdr) != 0)
        {
            printf("invalid icmp packet!\n");
            continue;
        }
    
        interval = getsystickcount64() - pichdr->icmp_timestamp;
        avgdelay+= interval;

        maxdelay = interval > maxdelay ? interval : maxdelay;
        mindelay = interval > mindelay ? mindelay : interval;
        
        printf("来自 %s 的回复: 字节=%d 时间=%dms TTL=%u\n",inet_ntoa(addrsrv.sin_addr),payload + sizeof(LONGLONG),interval,piphdr->ip_ttl);

        Sleep(1000);
    }

    printf("\n");
    printf("%s 的 Ping 统计信息: \n",inet_ntoa(addrsrv.sin_addr));
    printf("    数据包: 已发送 = %d, 已接收 = %d, 丢失 = %d (%.2f%% 丢失),\n",sndcnt,sndcnt-loscnt,loscnt,(loscnt * 100) / (double)sndcnt);
    printf("往返行程的估计时间(以毫秒为单位):\n");
    printf("    最短 = %dms, 最长 = %dms, 平均 = %dms\n",mindelay,maxdelay,avgdelay / sndcnt);
    printf("\n");
}

int main(int argc,char * argv[])
{
    ping("www.baidu.com",1464,4);
    return 0;
}