2024年4月17日发(作者：)

linux下ping命令的实现源码

// ping.c

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

#define BUFSIZE 1500

#define MAX_WAIT_TIME 5

#define MAX_NO_PACKETS 3

// Type of the ICMP header

typedef struct icmphdr

unsigned char type;

unsigned char code;

// Type of the ICMP

// Code of the ICMP

unsigned short checksum; // Checksum of the ICMP

unsigned short id; // ID of the ICMP

unsigned short sequence; // Sequence of the ICMP

} icmphdr;

// IP header's structure

struct iphdr

unsigned char h_verlen;

unsigned char tos;

// length of the header

// Type of service

unsigned short total_len; // Total length of packet

unsigned short ident; // Unique identifier

unsigned short frag_and_flags; // Flags

unsigned char ttl; // Time to live

// Protocol (TCP, UDP etc)

unsigned char proto;

unsigned short checksum; // IP checksum

unsigned int sourceIP;

unsigned int destIP;

};

// Source IP

// Destination IP

unsigned short checksum (unsigned short *addr, int len);

int pack(char *buf, int s, int seq);

int send_packet(int sockfd, struct sockaddr_in *addr, char

*sendpacket);

int recv_packet(int sockfd, char *buf, struct sockaddr_in

*addr);

int main(int argc, char *argv[])

struct hostent *host;

struct sockaddr_in addr;

int sockfd, size = 50 * 1024, cnt = MAX_NO_PACKETS, i;

char sendpacket[BUFSIZE], recvpacket[BUFSIZE];

struct sockaddr_in from;

int fromlen = sizeof(from);

// Check for the arguments

if (argc != 2)

printf("Usage: %s hostname/IP addressn", argv[0]);

exit(1);

}

// socket

sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);

if (sockfd < 0)

printf("Socket creating errorn");

exit(1);

}

// Get the hostname

if ((host = gethostbyname(argv[1])) == NULL)

printf("Hostname errorn");

exit(1);

}

// Make address structure

bzero(&addr, sizeof(addr));

_family = AF_INET;

_addr = *(struct in_addr *)host->h_addr;

_port = htons(0);

// set socket buffer size

if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &size,

sizeof(size)) == -1)

printf("Set socket buffer size errorn");

exit(1);

}

// Send the ICMP packet

for (i = 0; i < cnt; i++)