#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <unistd.h>
//#include <linux/if_packet.h>
#define PACKET_VNET_HDR 15

struct virtio_net_hdr
{
    uint8_t flags;
    uint8_t gso_type;
    uint16_t hdr_len;
    uint16_t gso_size;
    uint16_t csum_start;
    uint16_t csum_offset;
};
#define VIRTIO_NET_HDR_F_NEEDS_CSUM     1

unsigned char eth_hdr[] = {
	0x52, 0x54, 0x00, 0x3a, 0xbe, 0x28, 0x52, 0x54, 0x00, 0x74, 0x2f, 0xfd, 0x08, 0x00
};
unsigned char icmp_pkt[] = {
        0x45, 0x00, 0x00, 0x54, 0x11, 0xec, 0x40, 0x00, 0x40, 0x01, 0xb3, 0x58, 0xc0, 0xa8, 0x7a, 0x12,
        0xc0, 0xa8, 0x7a, 0x01, 0x08, 0x00, 0x00, 0x00, 0x07, 0xd2, 0x00, 0x01, 0x63, 0x7f, 0x02, 0x56,
        0x00, 0x00, 0x00, 0x00, 0x7c, 0x1b, 0x0b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x11, 0x12, 0x13,
        0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
        0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33,
        0x34, 0x35, 0x36, 0x37
};

unsigned char udp_pkt[] = {
	0x45, 0x00, 0x00, 0x22, 0xc4, 0x25, 0x40, 0x00, 0x40, 0x11, 0x01, 0x41, 0xc0, 0xa8, 0x7a, 0x12,
        0xc0, 0xa8, 0x7a, 0x01, 0xae, 0xc7, 0x1f, 0x90, 0x00, 0x0e, 0x75, 0x84, 0x68, 0x65, 0x6c, 0x6c,
        0x6f, 0x0a
};

int main(int argc, char **argv)
{
	struct ifreq req;
	struct sockaddr_ll lladdr;
	int fd, ret, val;
	struct {
		struct virtio_net_hdr vnet;
		unsigned char eth[14];
		unsigned char pkt[2048];
	} buf;

	if (argc != 2) {
		fprintf(stderr, "Usage: %s <ifname>\n", argv[0]);
		exit(1);
	}
	fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_IP));
	if (fd < 0) {
		perror("socket");
		exit(1);
	}

	memset(&req, 0, sizeof(req));
	strncpy(req.ifr_name, argv[1], IFNAMSIZ-1);
	ret = ioctl(fd, SIOCGIFINDEX, &req);
	if (ret < 0) {
		perror("SIOGIFINDEX");
		exit(1);
	}

	memset(&lladdr, 0, sizeof(lladdr));
	lladdr.sll_family   = AF_PACKET;
	lladdr.sll_protocol = htons(ETH_P_IP);
	lladdr.sll_ifindex  = req.ifr_ifindex;
	ret = bind(fd, (const struct sockaddr *)&lladdr, sizeof(lladdr));
	if (ret < 0) {
		perror("bind");
		exit(1);
	}

        val = 1;
        ret = setsockopt(fd, SOL_PACKET, PACKET_VNET_HDR, (const char *)&val,
			 sizeof(val));
        if (ret < 0) {
		perror("setsockopt(SOL_PACKET, PACKET_VNET_HDR)");
		exit(1);
	}

	memset(&buf.vnet, 0, sizeof(buf.vnet));
	memcpy(&buf.eth, eth_hdr, sizeof(eth_hdr));

	memcpy(&buf.pkt, udp_pkt, sizeof(udp_pkt));
	buf.vnet.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
	buf.vnet.csum_start = 0x22;
	buf.vnet.csum_offset = 0x6;
	if (write(fd, (void *)&buf, sizeof(buf.vnet) + 14 + sizeof(udp_pkt)) < 0) {
	        perror("Write UDP packet");
		exit(1);
	}

	memcpy(&buf.pkt, icmp_pkt, sizeof(icmp_pkt));
	buf.vnet.csum_offset = 0x2;
	if (write(fd, (void *)&buf, sizeof(buf.vnet) + 14 + sizeof(icmp_pkt)) < 0) {
		perror("Write ICMP packet");
		exit(1);
	}
	return 0;
}