/******************************************************************************
 *
 *       Filename:  raw_socket1.c
 *
 *    Description:  发送raw 网卡数据, 同一局域网下的pc运行wireshark抓包同时，运行此程序，就可以抓到上图中的数据包
 *
 *        Version:  1.0
 *        Created:  2021年07月07日 20时27分51秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  yangkun (yk)
 *          Email:  [email protected]
 *        Company:  yangkun.com
 *
 *****************************************************************************/
#include <net/ethernet.h> /* the L2 protocols */// ETH_P_ALL
#include <linux/if_packet.h>
#include <linux/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
// 发送mac层数据
int main()
{
    struct sockaddr_ll stTagAddr;
    memset(&stTagAddr, 0 , sizeof(stTagAddr));
    stTagAddr.sll_family    = AF_PACKET;//填写AF_PACKET,不再经协议层处理
    stTagAddr.sll_protocol  = htons(ETH_P_ALL);

    int ret;
    struct ifreq req;
    int sd;
    sd = socket(PF_INET, SOCK_DGRAM, 0);//这个sd就是用来获取eth0的index，完了就关闭
    if(sd == -1)
    {
        printf("error to create socket pf_inet:%s\n", strerror(errno));
        return -1;
    }

    // todo 此处需要更改为你使用的网卡名称
    char *eth_name = "enp3s0";
    strncpy(req.ifr_name, eth_name, strlen(eth_name));//通过设备名称获取index
    ret=ioctl(sd, SIOCGIFINDEX, &req);
    close(sd);
    if (ret==-1)
    {
           printf("Get eth0 index err:%d=>%s \n", errno, strerror(errno));
           return -1;
    }

    // int SockFd = socket(PF_PACKET, SOCK_RAW, htons(VSTRONG_PROTOCOL));
    int SockFd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
    if (-1 == SockFd)
    {
          printf("create socket error:%d.\n",errno); 
          return -11;
    }

    stTagAddr.sll_ifindex   = req.ifr_ifindex;//网卡eth0的index，非常重要，系统把数据往哪张网卡上发，就靠这个标识
    stTagAddr.sll_pkttype   = PACKET_OUTGOING;//标识包的类型为发出去的包
    stTagAddr.sll_halen     = 6;    //目标MAC地址长度为6
    //填写目标MAC地址
    stTagAddr.sll_addr[0]   = 0x2c;
    stTagAddr.sll_addr[1]   = 0xf0;
    stTagAddr.sll_addr[2]   = 0x5d;
    stTagAddr.sll_addr[3]   = 0x6e;
    stTagAddr.sll_addr[4]   = 0x3e;
    stTagAddr.sll_addr[5]   = 0xa6;
    //填充帧头和内容
    char szbuff[20] = "abcdefg123456";
    // 这样网卡会把sebuff中的内容发送出去
    int i32Len = sendto(SockFd, (char *)szbuff, sizeof(szbuff), 0, (const struct sockaddr *)&stTagAddr, sizeof(stTagAddr));
    if(-1 == i32Len)
    {
        printf("error to send data:errno=%d=>%s\n", errno, strerror(errno));
        return -1;
    }
}

/******************************************************************************
 *
 *       Filename:  raw_socket2.c
 *
 *    Description:  发送raw 网卡数据
 *
 *        Version:  2.0
 *        Created:  2021年07月07日 20时27分51秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  yangkun (yk)
 *          Email:  [email protected]
 *        Company:  yangkun.com
 *
 *****************************************************************************/
#include <net/ethernet.h> /* the L2 protocols */// ETH_P_ALL
#include <linux/if_packet.h>
#include <linux/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <netinet/ip.h> // ip head
#include <netinet/udp.h> // udp head

#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

// 校验和函数
unsigned short csum(unsigned short *buf, int nwords)
{
    unsigned long sum;
    for(sum=0; nwords>0; nwords--)
        sum += *buf++;
    sum = (sum >> 16) + (sum &0xffff);
    sum += (sum >> 16);
    return (unsigned short)(~sum);
}

// 发送mac层数据
int main()
{
    struct sockaddr_ll stTagAddr;
    memset(&stTagAddr, 0 , sizeof(stTagAddr));
    stTagAddr.sll_family    = AF_PACKET;//填写AF_PACKET,不再经协议层处理
    stTagAddr.sll_protocol  = htons(ETH_P_ALL);

    int ret;
    struct ifreq req;
    int sd;
    sd = socket(PF_INET, SOCK_DGRAM, 0);//这个sd就是用来获取eth0的index，完了就关闭
    if(sd == -1)
    {
        printf("error to create socket pf_inet:%s\n", strerror(errno));
        return -1;
    }

    // todo 此处需要更改为你使用的网卡名称
    char *eth_name = "enp3s0";
    strncpy(req.ifr_name, eth_name, strlen(eth_name));//通过设备名称获取index
    ret=ioctl(sd, SIOCGIFINDEX, &req);
    if(ret <0)
    {
        perror("SIOCGIFHWADDR");
        return -1;
    }
    
    // 获取mac地址
    struct ifreq if_mac;
    memset(&if_mac, 0, sizeof(struct ifreq));
    strncpy(if_mac.ifr_name, eth_name, strlen(eth_name));
    if (ioctl(sd, SIOCGIFHWADDR, &if_mac) < 0)
    {
        perror("SIOCGIFHWADDR");
        return -1;
    }


    close(sd);
    if (ret==-1)
    {
           printf("Get eth0 index err:%d=>%s \n", errno, strerror(errno));
           return -1;
    }

    // int SockFd = socket(PF_PACKET, SOCK_RAW, htons(VSTRONG_PROTOCOL));
    int SockFd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
    if (-1 == SockFd)
    {
          printf("create socket error:%d.\n",errno); 
          return -11;
    }

    stTagAddr.sll_ifindex   = req.ifr_ifindex;//网卡eth0的index，非常重要，系统把数据往哪张网卡上发，就靠这个标识
    stTagAddr.sll_pkttype   = PACKET_OUTGOING;//标识包的类型为发出去的包
    stTagAddr.sll_halen     = 6;    //目标MAC地址长度为6
    //填写目标MAC地址
    stTagAddr.sll_addr[0]   = 0x2c;
    stTagAddr.sll_addr[1]   = 0xf0;
    stTagAddr.sll_addr[2]   = 0x5d;
    stTagAddr.sll_addr[3]   = 0x6e;
    stTagAddr.sll_addr[4]   = 0x3e;
    stTagAddr.sll_addr[5]   = 0xa6;
    //填充帧头和内容
    // 构造ethernet header
    int tx_len = 0;
    char sendbuf[1024];
    struct ether_header *eh = (struct ether_header *) sendbuf;
    memset(sendbuf, 0, 1024);
    /* Ethernet header */
    // 此处应该根据源mac 和 目的mac做更改
    eh->ether_shost[0] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[0];
    eh->ether_shost[1] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[1];
    eh->ether_shost[2] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[2];
    eh->ether_shost[3] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[3];
    eh->ether_shost[4] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[4];
    eh->ether_shost[5] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[5];
    eh->ether_dhost[0] = 0x2c;
    eh->ether_dhost[1] = 0xf0;
    eh->ether_dhost[2] = 0x5d;
    eh->ether_dhost[3] = 0x6e;
    eh->ether_dhost[4] = 0x3e;
    eh->ether_dhost[5] = 0xa6;
    eh->ether_type = htons(ETH_P_IP);
    tx_len += sizeof(struct ether_header);

    // 构造ip 头
    struct iphdr *iph = (struct iphdr *) (sendbuf + sizeof(struct ether_header));
    int ttl = 20;
    /* IP Header */
    iph->ihl = 5;
    iph->version = 4;
    iph->tos = 16; // Low delay
    iph->id = htons(54321);
    iph->ttl = ttl; // hops
    iph->protocol = 17; // UDP
    /* Source IP address, can be spoofed */
    //iph->saddr = inet_addr(inet_ntoa(((struct sockaddr_in *)&if_ip.ifr_addr)->sin_addr));
    // 此处要更改源ip和目的ip
    iph->saddr = inet_addr("172.20.2.7");
    /* Destination IP address */
    iph->daddr = inet_addr("172.20.2.76");
    tx_len += sizeof(struct iphdr);
    
    // 构建udp 数据头
    struct udphdr *udph = (struct udphdr *) (sendbuf + sizeof(struct iphdr) + sizeof(struct ether_header));
    /* UDP Header */
    // 源端口, 目的端口
    udph->source = htons(3423);
    udph->dest = htons(5342);
    udph->check = 0; // skip
    tx_len += sizeof(struct udphdr);

    //udp 数据
    /* Packet data */
    sendbuf[tx_len++] = 0xde;
    sendbuf[tx_len++] = 0xad;
    sendbuf[tx_len++] = 0xbe;
    sendbuf[tx_len++] = 0xef;

    // 填充头校验信息
    /* Length of UDP payload and header */
    udph->len = htons(tx_len - sizeof(struct ether_header) - sizeof(struct iphdr));
    /* Length of IP payload and header */
    iph->tot_len = htons(tx_len - sizeof(struct ether_header));
    /* Calculate IP checksum on completed header */
    iph->check = csum((unsigned short *)(sendbuf+sizeof(struct ether_header)), sizeof(struct iphdr)/2);

    // 这样网卡会把sebuff中的内容发送出去
    int i32Len = sendto(SockFd, (char *)sendbuf, tx_len, 0, (const struct sockaddr *)&stTagAddr, sizeof(stTagAddr));
    if(-1 == i32Len)
    {
        printf("error to send data:errno=%d=>%s\n", errno, strerror(errno));
        return -1;
    }
}