前言
最近和同事测试网络带宽问题， 分析网络稳定性的问题时，在网上没有找到合适工具， 我发现网上测试网络带宽的原理都是ping一样的原理就研究一下
ping工具一直是我们使用测量网络是否相通。它的应用有很多，比如我们经常测试网络的带宽，网络安全，使用ICMP攻击使服务器繁忙，DOS攻击
正文
一, ping的原理介绍
ping使用协议在网络ISO中那一层
ping使用ICMP在网络层， 有IP头
里面有一个首部校验
这样我们就可以定义出IP头结构体
typedef struct IPhead
{
//这里使用了C语言的位域，也就是说像version变量它的大小在内存中是占4bit，而不是8bit
uint8_t version : 4; //IP协议版本
uint8_t headLength : 4;//首部长度
uint8_t serverce;//区分服务
uint16_t totalLength;//总长度
uint16_t flagbit;//标识
uint16_t flag : 3;//标志
uint16_t fragmentOffset : 13;//片偏移
char timetoLive;//生存时间（跳数）
uint8_t protocol;//使用协议
uint16_t headcheckSum;//首部校验和
uint32_t srcIPadd;//源IP
uint32_t dstIPadd;//目的IP
//可选项和填充我就不定义了
} IPhead;
我们由最上面图可知道还需要ICMP协议
icmp协议分为请求包和响应包
ICMP协议结构体的定义
//ICMP头
typedef struct ICMPhead
{
uint8_t type;//类型
uint8_t code;//代码
uint16_t checkSum;//校验和
uint16_t ident;//进程标识符
uint16_t seqNum;//序号
} ICMPhead;
//ICMP回显请求报文(发送用)
typedef struct ICMP
{
ICMPhead icmphead;//头部
uint32_t timeStamp;//时间戳
char data[1000];//数据
};
//ICMP应答报文(接收用)
typedef struct ICMPReply
{
IPhead iphead;//IP头
ICMP icmpanswer;//ICMP报文
char data[1024];//应答报文携带的数据缓冲区
} ICMPReply;
二, 实现ping
#include <stdio.h>
#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <sys/time.h>
#include <poll.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <math.h>
#include <fstream>
#include <ctime>
std::ofstream g_fd;
int time64_datetime_format(time_t time, char* out, char date_conn, char datetime_conn, char time_conn)
{
int nCount = 0;
tm now_tm;
::gmtime_r(&time, &now_tm);
if (date_conn > 0)
{
nCount += sprintf(out + nCount, "%04d%c%02d%c%02d", now_tm.tm_year + 1900, date_conn
, now_tm.tm_mon + 1, date_conn, now_tm.tm_mday);
}
else if(date_conn == 0)
{
nCount += sprintf(out + nCount, "%04d%02d%02d", now_tm.tm_year + 1900, now_tm.tm_mon + 1
, now_tm.tm_mday);
}
if (datetime_conn > 0)
{
out[nCount] = datetime_conn;
++nCount;
out[nCount] = '\0';
}
if (time_conn > 0)
{
nCount += sprintf(out + nCount, "%02d%c%02d%c%02d", now_tm.tm_hour, time_conn
, now_tm.tm_min, time_conn, now_tm.tm_sec);
}
else if (time_conn == 0)
{
nCount += sprintf(out + nCount, "%02d%02d%02d", now_tm.tm_hour, now_tm.tm_min, now_tm.tm_sec);
}
return nCount;
}
typedef struct IPhead
{
//这里使用了C语言的位域，也就是说像version变量它的大小在内存中是占4bit，而不是8bit
uint8_t version : 4; //IP协议版本
uint8_t headLength : 4;//首部长度
uint8_t serverce;//区分服务
uint16_t totalLength;//总长度
uint16_t flagbit;//标识
uint16_t flag : 3;//标志
uint16_t fragmentOffset : 13;//片偏移
char timetoLive;//生存时间（跳数）
uint8_t protocol;//使用协议
uint16_t headcheckSum;//首部校验和
uint32_t srcIPadd;//源IP
uint32_t dstIPadd;//目的IP
//可选项和填充我就不定义了
} IPhead;
//ICMP头
typedef struct ICMPhead
{
uint8_t type;//类型
uint8_t code;//代码
uint16_t checkSum;//校验和
uint16_t ident;//进程标识符
uint16_t seqNum;//序号
} ICMPhead;
//ICMP回显请求报文(发送用)
typedef struct ICMP
{
ICMPhead icmphead;//头部
uint32_t timeStamp;//时间戳
char data[1000];//数据
};
//ICMP应答报文(接收用)
typedef struct ICMPReply
{
IPhead iphead;//IP头
ICMP icmpanswer;//ICMP报文
char data[1024];//应答报文携带的数据缓冲区
} ICMPReply;
static uint16_t getCheckSum(void * protocol)
{
uint32_t checkSum = 0;
uint16_t* word = (uint16_t*)protocol;
uint32_t size = sizeof(ICMP);
while (size > 1)//用32位变量来存是因为要存储16位数相加可能发生的溢出情况，将溢出的最高位最后加到16位的最低位上
{
checkSum += *word++;
// printf("[%s:%d]checkSum:0x%x\n", __FUNCTION__, __LINE__, checkSum);
size -=sizeof(uint16_t);
}
if (size)
{
checkSum += *(uint8_t*)word;
// printf("[%s:%d]checkSum:0x%x\n", __FUNCTION__, __LINE__, checkSum);
}
//二进制反码求和运算，先取反在相加和先相加在取反的结果是一样的，所以先全部相加在取反
//计算加上溢出后的结果
// while (checkSum >> 16) {
// checkSum = (checkSum >> 16) + (checkSum & 0xffff);
// }
checkSum =(checkSum >> 16) + (checkSum & 0xffff);
// printf("[%s:%d]checkSum:0x%x\n", __FUNCTION__, __LINE__, checkSum);
checkSum +=(checkSum >> 16);
// printf("[%s:%d]checkSum:0x%x\n", __FUNCTION__, __LINE__, checkSum);
//取反
return (~checkSum);
}
static bool sendICMPReq(int mysocket, sockaddr_in &dstAddr,unsigned int num)
{
struct timeval tv;
//创建ICMP请求回显报文
//设置回显请求
ICMP myIcmp;//ICMP请求报文
myIcmp.icmphead.type = 8;
myIcmp.icmphead.code = 0;
//设置初始检验和为0
myIcmp.icmphead.checkSum = 0;
//获得一个进程标识
myIcmp.icmphead.ident = (uint16_t)getpid();
//设置当前序号为0
myIcmp.icmphead.seqNum = ++num;
//保存发送时间
gettimeofday(&tv, NULL);
myIcmp.timeStamp = tv.tv_sec * 1000 + tv.tv_usec / 1000;
// myIcmp.timeStamp = GetTickCount();
//计算并且保存校验和
myIcmp.icmphead.checkSum = getCheckSum((void*)&myIcmp);
//发送报文
printf("[%s:%d]checkSum:0x%x\n", __FUNCTION__, __LINE__, myIcmp.icmphead.checkSum);
printf("[%s:%d]send timeStamp:%lld\n", __FUNCTION__, __LINE__, myIcmp.timeStamp);
int len = sendto(mysocket, (char*)&myIcmp, sizeof(ICMP), 0, (sockaddr*)&dstAddr, sizeof(sockaddr_in));
if (len < 0)
{
printf("sendto len:%d\n", len);
std::cerr << "socket 发送错误:" << errno << std::endl;
return false;
}
return true;
}
// int waitForSocket(int mysocket)
// {
// //5S 等待套接字是否由数据
// timeval timeOut;
// fd_set readfd;
// readfd.fd_count = 1;
// readfd.fd_array[0] = mysocket;
// timeOut.tv_sec = 5;
// timeOut.tv_usec = 0;
// return (select(1, &readfd, NULL, NULL, &timeOut));
// }
static int waitForSocket(int fd, int write)
{
int ev = write ? POLLOUT : POLLIN;
struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };
int ret;
ret = poll(&p, 1, 2000);
return ret < 0 ? ret : p.revents & (ev | POLLERR | POLLHUP) ? 0 : 1;
}
static int64_t readICMPanswer(int mysocket, sockaddr_in &srcAddr, char &TTL)
{
ICMPReply icmpReply;//接收应答报文
int addrLen = sizeof(sockaddr_in);
//接收应答
int len = recvfrom(mysocket, (char*)&icmpReply, sizeof(ICMPReply), 0, (sockaddr*)&srcAddr, (socklen_t *)&addrLen);
printf("[%s:%d]recv len:%d\n", __FUNCTION__, __LINE__, len);
if (len < 0)
{
std::cerr << "socket 接收错误:" << errno << std::endl;
return -1;
}
//读取校验并重新计算对比
uint16_t checkSum = icmpReply.icmpanswer.icmphead.checkSum;
//因为发出去的时候计算的校验和是0
icmpReply.icmpanswer.icmphead.checkSum = 0;
printf("[%s:%d]recv timeStamp:%lld\n", __FUNCTION__, __LINE__, icmpReply.icmpanswer.timeStamp);
//重新计算
if (checkSum == getCheckSum((void*)&icmpReply.icmpanswer)) {
//获取TTL值
TTL = icmpReply.iphead.timetoLive;
return icmpReply.icmpanswer.timeStamp;
}
return -1;
}
static void doPing(int mysocket, sockaddr_in & srcAddr, sockaddr_in & dstAddr, int num)
{
int64_t timeSent;//发送时的时间
uint32_t timeElapsed;//延迟时间
char TTL;//跳数
struct timeval tv;
//发送ICMP回显请求
sendICMPReq(mysocket, dstAddr, num);
//等待数据
int ret = waitForSocket(mysocket, 0);
if (ret < 0)
{
std::cerr << "socket发生错误:" << errno << std::endl;
return;
}
if (ret > 0)
{
std::cout << "请求超时:" << std::endl;
return;
}
timeSent = readICMPanswer(mysocket, srcAddr, TTL);
printf("[%s:%d]timeSent:%u\n", __FUNCTION__, __LINE__, (uint32_t)timeSent);
if (!g_fd.is_open())
{
//std::cout << "not open log file dest url = " << log_name << std::endl;
g_fd.open("ping.csv", std::ios::out | std::ios::trunc);
if (!g_fd.is_open())
{
std::cout << "not open log file dest url = " << "" << std::endl;
}
//return false;
}
static int row_num = 0;
char buf[1024] = {0};
if (row_num == 0)
{
g_fd << "date, M/s" << std::endl;
++row_num;
}
time64_datetime_format(::time(NULL), buf, '-', ' ', ':');
g_fd << buf << ",";
if (timeSent != -1) {
gettimeofday(&tv, NULL);
uint32_t timer_sec_usec = tv.tv_sec * 1000 + tv.tv_usec / 1000;
printf("[cur_time = %lld]\n", timer_sec_usec);
timeElapsed = (timer_sec_usec) - timeSent;
//double speed_time = static_cast<double>( timeElapsed / 1000)
//输出信息，注意TTL值是ASCII码，要进行转换
double temp_speed = static_cast<double>( 1000 * 8 / timeElapsed );
std::cout << "[dst " << inet_ntoa(srcAddr.sin_addr) << " recv: byte= " << sizeof(((ICMP *)0)->data) << " time= " << timeElapsed << "ms TTL= " << fabs((int)TTL) << "]" << std::endl;
std::cout << "[ speed = " << temp_speed << " bps/ms]" << std::endl;
uint32_t bps_time = temp_speed * 1000 ;
std::cout << "[ speed = " << bps_time << " bps/s]" << std::endl;
//std::cout << "[ speed = " << bps_time / 1000000 << " Mbps/s]" << std::endl;
g_fd << temp_speed << std::endl;
}
else {
std::cout << "请求超时" << std::endl;
g_fd << 0 << std::endl;
}
//g_fd.write('\n', 1);
g_fd.flush();
}
static int ping(const char * dstIPaddr, short port)
{
int rawSocket;//socket
sockaddr_in srcAddr;//socket源地址
sockaddr_in dstAddr;//socket目的地址
int Ret;//捕获状态值
char TTL = '0';//跳数
//生成一个套接字
//TCP/IP协议族,RAW模式，ICMP协议
//RAW创建的是一个原始套接字，最低可以访问到数据链路层的数据，也就是说在网络层的IP头的数据也可以拿到了。
// rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
printf("[%s:%d]rawSocket:%d\n", __FUNCTION__, __LINE__, rawSocket);
if (rawSocket < 0) {
printf("[%s:%d]socket create err:<%d> rawSocket:%d\n", __FUNCTION__, __LINE__, errno, rawSocket);
return -1;
}
//设置目标IP地址
dstAddr.sin_addr.s_addr = inet_addr(dstIPaddr);
//端口
dstAddr.sin_port = htons(port);
//协议族
dstAddr.sin_family = AF_INET;
//提示信息
printf("ping address:%s bytes:%d\n", inet_ntoa(dstAddr.sin_addr), sizeof(((ICMP *)0)->data));
//执行4次ping
for (int i = 0; i < 4000000000; i++)
{
doPing(rawSocket, srcAddr, dstAddr, i);
usleep(1000000);
}
close(rawSocket);
return 0;
}
int main(int argc, char *argv[]) {
char *addr = "127.0.0.1";
printf("start ping ...\n");
// ping("172.16.20.202", 0);
if (argc > 1) {
addr = argv[1];
}
ping(addr, 0);
printf("end ping ...\n");
}
