Ethernet frame structure of computer network

The structure of an Ethernet frame

#include <linux/if_ether.h>

struct eth_hdr
{
    
    
    unsigned char dmac[6];  //目的mac地址(6字节)
    unsigned char smac[6];  //源mac地址(6字节)
    uint16_t ethertype;     //如果字段的值大于或等于1536,则该字段包含有效载荷的类型(例如IPv4,ARP),如果该值小于该值,则它包含有效载荷的长度
    unsigned char payload[];//数据字段,最小长度必须为46字节以保证帧长至少为64字节,最大长度为1500字节
} __attribute__((packed));

The Ethernet frame is also followed by a cyclic redundancy check field (FCS) to provide an error detection mechanism. The field length is 4 bytes.

That’s all, simplicity is better than complexity