#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <net/if.h>
#include <net/bpf.h>
#include <sys/socket.h>
#include <sys/sockio.h>

char packet[] =
	"\xff\xff\xff\xff\xff\xff"
	"\x00\x1c\x25\xa0\xb7\x2e"
	"\x08\x06\x00\x01"
	"\x08\x00\x06\x04\x00\x01"
	"\x00\x1c\x25\xa0\xb7\x2e"
	"\x0a\x00\x00\x0d"
	"\xff\xff\xff\xff\xff\xff"
	"\x0a\x00\x00\x3d"
	"\x00\x00\x00\x00\x00\x00"
	"\x00\x00\x00\x00\x00\x00"
	"\x00\x00\x00\x00\x00\x00"
;

int
send_bpf(const char *iface, char *data, size_t len)
{
	int fd = open("/dev/bpf", O_RDWR);
	if (fd < 0) {
		perror("open");
		return -1;
	}

	struct ifreq ifr;

	(void) memset(&ifr, 0, sizeof ifr);
	(void) memcpy(&ifr.ifr_name, iface, strlen(iface));
	if (ioctl(fd, BIOCSETIF, &ifr) < 0) {
		perror("BIOCSETIF");
		return -2;
	}

	int enable;
       
	enable = 1;
	if (ioctl(fd, BIOCIMMEDIATE, &enable) < 0) {
		perror("BIOCIMMEDIATE");
		return -3;
	}

	enable = 1;
	if (ioctl(fd, BIOCSHDRCMPLT, &enable) < 0) {
		perror("BIOCSHDRCMPLT");
		return -4;
	}

	size_t ret = write(fd, data, len);
	if (ret >= 0)
		printf("send_bpf sent %ld bytes\n", ret);
	if (ret != len) {
		fprintf(stderr, "write returned %ld, expected %ld\n", ret, len);
		return -5;
	}

	if (close(fd) < 0) {
		perror("close");
		return -6;
	}

	return 0;
}

int
send_socket(const char *iface, char *data, size_t len)
{
	int s = socket(AF_PACKET, SOCK_RAW, 0);
	if (s < 0) {
		perror("socket");
		return -1;
	}

	struct ifreq ifr;

	(void) memset(&ifr, 0, sizeof ifr);
	(void) memcpy(&ifr.ifr_name, iface, strlen(iface));
	if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
		perror("SIOCGIFINDEX");
		return -2;
	}

	struct sockaddr_ll lls;
	(void) memset(&lls, 0, sizeof lls);
	lls.sll_family = AF_PACKET;
	lls.sll_protocol = 0;
	lls.sll_ifindex = ifr.ifr_index;

	if (bind(s, (struct sockaddr *)&lls, sizeof lls) < 0) {
		perror("bind");
		return -3;
	}

	size_t ret = send(s, data, len, 0);
	if (ret >= 0)
		printf("send_socket sent %ld bytes\n", ret);
	if (ret != len) {
		fprintf(stderr, "send returned %ld, expected %ld\n", ret, len);
		return -4;
	}

	if (close(s) < 0) {
		perror("close");
		return -5;
	}

	return 0;
}

int main(int argc, char *argv[])
{
	if (argc != 2) {
		fprintf(stderr, "Missing interface\n");
		return 1;
	}

	int ret;

	ret = send_bpf(argv[1], packet, sizeof packet - 1);
	if (ret != 0)
		fprintf(stderr, "send_bpf: %d\n", ret);

	ret = send_socket(argv[1], packet, sizeof packet - 1);
	if (ret != 0)
		fprintf(stderr, "send_socket: %d\n", ret);

	return 0;
}