icmp ping实现C语言

### 实现ICMP Ping功能 为了在 Linux 中使用 C 语言实现 ICMP Ping 功能，程序需要创建原始套接字并发送 ICMP 请求消息给目标主机。下面是一个简化版本的代码示例： ```c #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <arpa/inet.h> #include <sys/socket.h> #define BUFFER_SIZE 60 void create_icmp_packet(char *buffer, int id) { struct icmp { unsigned char type; unsigned char code; unsigned short checksum; unsigned short identifier; unsigned short sequence_number; } __attribute__((packed)) packet; packet.type = 8; /* Echo request */ packet.code = 0; packet.checksum = 0; packet.identifier = htons(id); packet.sequence_number = htons(1); memcpy(buffer, &packet, sizeof(packet)); } unsigned short calculate_checksum(unsigned short *addr, int len) { int nleft = len; int sum = 0; unsigned short answer = 0; unsigned short *w = addr; while (nleft > 1) { sum += *w++; nleft -= 2; } if (nleft == 1) { *(u_char *) (&answer) = *(u_char *) w; sum += answer; } sum = (sum >> 16) + (sum & 0xffff); sum += (sum >> 16); answer = ~sum; return answer; } int main(int argc, char **argv) { if (argc != 3) { fprintf(stderr, "Usage: %s <IP address> <identifier>\n", argv[0]); exit(EXIT_FAILURE); } const char *target_ip = argv[1]; int id = atoi(argv[2]); int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); if (sockfd < 0) { perror("socket"); exit(EXIT_FAILURE); } char buffer[BUFFER_SIZE]; memset(buffer, '\0', BUFFER_SIZE); create_icmp_packet(buffer, id); struct sockaddr_in dest_addr; dest_addr.sin_family = AF_INET; inet_pton(AF_INET, target_ip, &(dest_addr.sin_addr)); sendto(sockfd, buffer, sizeof(struct icmp), 0, (struct sockaddr *)&dest_addr, sizeof(dest_addr)); close(sockfd); printf("Ping sent to IP: %s with ID: %d\n", target_ip, id); } ``` 上述代码展示了如何构建一个简单的 ICMP echo 请求报文，并通过原始套接字将其发送到指定的目标地址[^1]。