/*-
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 69):
 * <syrinx@FreeBSD.org> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   -Shteryana Shopova
 * ----------------------------------------------------------------------------
 */
#include <sys/types.h>
#include <sys/limits.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#include <arpa/inet.h>
#include <netinet/in.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>


#include <net/ethernet.h>
#include <net/if.h>
#include <net/netmap.h>
#include <net/netmap_user.h>

#define		NETMAP_DEV	"/dev/netmap"
struct nmgen {
	void			*pkts;
	size_t			plen;
	struct pollfd		fds;
	struct nmreq		nmr;
} ng;

static void	cleanup(void);

const char lldp_ttl_big[] =  "\
\x04\x7d\x7b\xa8\xf0\xb9\x00\xa0\x12\x22\x22\x22\x88\xcc\x02\x07\
\x04\x00\xa0\x12\x1b\x00\xa6\x04\x07\x03\x00\xa0\x12\x1b\x00\xa8\
\x06\x02\xff\xff\x10\x0c\x05\x01\x0a\x03\xd9\xd9\x02\x00\x00\x00\
\x02\x00\x10\x0c\x05\x01\x0b\x00\x00\x01\x02\x00\x00\x00\x03\x00\
\x10\x0c\x05\x01\x7f\x00\x00\x01\x02\x00\x00\x00\x01\x00\x10\x0e\
\x07\x06\x00\xa0\x12\x1b\x00\xa6\x02\x00\x00\x00\x00\x00\x08\x14\
\x50\x68\x79\x73\x69\x63\x61\x6c\x20\x49\x6e\x74\x65\x72\x66\x61\
\x63\x65\x20\x32\x0c\x44\x4e\x4f\x4b\x49\x41\x20\x45\x53\x42\x32\
\x36\x20\x73\x6f\x66\x74\x77\x61\x72\x65\x20\x76\x65\x72\x73\x69\
\x6f\x6e\x20\x34\x2e\x34\x2e\x30\x20\x62\x75\x69\x6c\x64\x20\x30\
\x33\x20\x20\x20\x4e\x6f\x76\x20\x32\x39\x20\x32\x30\x30\x36\x20\
\x2d\x20\x31\x37\x3a\x30\x39\x3a\x30\x34\x0e\x04\x00\x12\x00\x12\
\x00\x00";
 
int
main(int argc, char **argv, char **envp)
{
	int i;
	char *buf;
	struct netmap_if *nifp;
	struct netmap_ring *ring;

	bzero(&ng, sizeof(struct nmgen));
	ng.fds.fd = -1;

	if (argc != 2){	
		printf ("Usage: %s <ifname> \n", argv[0]);
		exit(0);
	}

	if (atexit(cleanup) != 0)
		err(1, "Failed to register cleanup routine");

	if ((ng.fds.fd = open(NETMAP_DEV, O_RDWR)) == -1)
		err(1, "open(NETMAP_DEV) failed");

	bzero(&(ng.nmr), sizeof(ng.nmr));
	strlcpy(ng.nmr.nr_name, argv[1], sizeof(ng.nmr.nr_name));
	ng.nmr.nr_version = NETMAP_API;
	if ((ioctl(ng.fds.fd , NIOCGINFO, &(ng.nmr))) == -1)
		err(1, "Failed to bind to interface %s", argv[1]);


	ng.plen = ng.nmr.nr_memsize;
	if ((ng.pkts = mmap(NULL, ng.nmr.nr_memsize, PROT_READ | PROT_WRITE,
	    MAP_SHARED, ng.fds.fd, 0)) == MAP_FAILED)
		err(1, "Failed to alloc memory");

	if ((ioctl(ng.fds.fd , NIOCREGIF, &(ng.nmr))) == -1)
		err(1, "Failed to bind to interface %s", argv[1]);


	nifp = NETMAP_IF(ng.pkts, ng.nmr.nr_offset);
	ring = NETMAP_TXRING(nifp, 0);
	ng.fds.events = POLLOUT | POLLWRNORM | POLLWRBAND;

	printf("Available buffers in ring %d\n", ring->avail);
	ng.plen = ring->avail;

	for (;;) {
		for ( ; ring->avail > 0 ; ring->avail--) {
			i = ring->cur;
			buf = NETMAP_BUF(ring, ring->slot[i].buf_idx);
			memcpy(buf, lldp_ttl_big, sizeof(lldp_ttl_big));
			ring->slot[i].len = sizeof(lldp_ttl_big);
			buf[ETHER_ADDR_LEN - 1] = i;
			buf[2 * ETHER_ADDR_LEN - 1] = i;
			ring->cur = NETMAP_RING_NEXT(ring, i);
		}
		ring->flags = NR_TIMESTAMP | NR_FORWARD;
		if (poll(&(ng.fds), 1, 2000 /*INFTIM*/) == -1)
			err(1, "Poll error");

		if (ioctl(ng.fds.fd, NIOCTXSYNC, NULL) == -1)
			errx(1, "ioctl(NIOCTXSYNC) failed");
	}

	exit(0);
}

static void
cleanup(void)
{
	if (ng.pkts != NULL)
		munmap(ng.pkts, ng.plen);
	if (ng.fds.fd  != -1)
		close(ng.fds.fd);
}