/*-
 * Copyright (c) 2016 Yandex LLC
 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_pflog.h>
#include <net/if_var.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/vnet.h>
#include <net/bpf.h>

#include <netinet/in.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_var.h>
#include <netpfil/ipfw/ip_fw_private.h>

static VNET_DEFINE(struct ifnet *, log_if);
static VNET_DEFINE(struct ifnet *, pflog_if);
static VNET_DEFINE(struct if_clone *, ipfw_cloner);
static VNET_DEFINE(struct if_clone *, ipfwlog_cloner);
#define	V_ipfw_cloner		VNET(ipfw_cloner)
#define	V_ipfwlog_cloner	VNET(ipfwlog_cloner)
#define	V_log_if		VNET(log_if)
#define	V_pflog_if		VNET(pflog_if)

static struct rmlock log_if_lock;
#define	LOGIF_LOCK_INIT(x)	rm_init(&log_if_lock, "ipfw log_if lock")
#define	LOGIF_LOCK_DESTROY(x)	rm_destroy(&log_if_lock)
#define	LOGIF_RLOCK_TRACKER	struct rm_priotracker _log_tracker
#define	LOGIF_RLOCK(x)		rm_rlock(&log_if_lock, &_log_tracker)
#define	LOGIF_RUNLOCK(x)	rm_runlock(&log_if_lock, &_log_tracker)
#define	LOGIF_WLOCK(x)		rm_wlock(&log_if_lock)
#define	LOGIF_WUNLOCK(x)	rm_wunlock(&log_if_lock)

static const char ipfwname[] = "ipfw";
static const char ipfwlogname[] = "ipfwlog";

static int
ipfw_bpf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
{

	return (EINVAL);
}

static int
ipfw_bpf_output(struct ifnet *ifp, struct mbuf *m,
	const struct sockaddr *dst, struct route *ro)
{

	if (m != NULL)
		FREE_PKT(m);
	return (0);
}

static void
ipfw_clone_destroy(struct ifnet *ifp)
{

	LOGIF_WLOCK();
	if (ifp->if_hdrlen == ETHER_HDR_LEN)
		V_log_if = NULL;
	else
		V_pflog_if = NULL;
	LOGIF_WUNLOCK();

	bpfdetach(ifp);
	if_detach(ifp);
	if_free(ifp);
}

static int
ipfw_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
	struct ifnet *ifp;

	ifp = if_alloc(IFT_PFLOG);
	if (ifp == NULL)
		return (ENOSPC);
	if_initname(ifp, ipfwname, unit);
	ifp->if_flags = IFF_UP | IFF_SIMPLEX | IFF_MULTICAST;
	ifp->if_mtu = 65536;
	ifp->if_ioctl = ipfw_bpf_ioctl;
	ifp->if_output = ipfw_bpf_output;
	ifp->if_hdrlen = ETHER_HDR_LEN;
	if_attach(ifp);
	bpfattach(ifp, DLT_EN10MB, ETHER_HDR_LEN);
	LOGIF_WLOCK();
	if (V_log_if != NULL) {
		LOGIF_WUNLOCK();
		bpfdetach(ifp);
		if_detach(ifp);
		if_free(ifp);
		return (EEXIST);
	}
	V_log_if = ifp;
	LOGIF_WUNLOCK();
	return (0);
}

static int
ipfwlog_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
	struct ifnet *ifp;

	ifp = if_alloc(IFT_PFLOG);
	if (ifp == NULL)
		return (ENOSPC);
	if_initname(ifp, ipfwlogname, unit);
	ifp->if_flags = IFF_UP | IFF_SIMPLEX | IFF_MULTICAST;
	ifp->if_mtu = 65536;
	ifp->if_ioctl = ipfw_bpf_ioctl;
	ifp->if_output = ipfw_bpf_output;
	ifp->if_hdrlen = PFLOG_HDRLEN;
	if_attach(ifp);
	bpfattach(ifp, DLT_PFLOG, PFLOG_HDRLEN);
	LOGIF_WLOCK();
	if (V_pflog_if != NULL) {
		LOGIF_WUNLOCK();
		bpfdetach(ifp);
		if_detach(ifp);
		if_free(ifp);
		return (EEXIST);
	}
	V_pflog_if = ifp;
	LOGIF_WUNLOCK();
	return (0);
}

void
ipfw_bpf_mtap2(void *data, u_int dlen, struct mbuf *m)
{
	LOGIF_RLOCK_TRACKER;

	LOGIF_RLOCK();
	if (dlen == ETHER_HDR_LEN) {
		if (V_log_if == NULL) {
			LOGIF_RUNLOCK();
			return;
		}
		BPF_MTAP2(V_log_if, data, dlen, m);
	} else if (dlen == PFLOG_HDRLEN) {
		if (V_pflog_if == NULL) {
			LOGIF_RUNLOCK();
			return;
		}
		BPF_MTAP2(V_pflog_if, data, dlen, m);
	}
	LOGIF_RUNLOCK();
}

void
ipfw_bpf_init(int first)
{

	if (first) {
		LOGIF_LOCK_INIT();
		V_log_if = NULL;
		V_pflog_if = NULL;
	}
	V_ipfw_cloner = if_clone_simple(ipfwname, ipfw_clone_create,
	    ipfw_clone_destroy, 0);
	V_ipfwlog_cloner = if_clone_simple(ipfwlogname, ipfwlog_clone_create,
	    ipfw_clone_destroy, 0);
}

void
ipfw_bpf_uninit(int last)
{

	if_clone_detach(V_ipfw_cloner);
	if_clone_detach(V_ipfwlog_cloner);
	if (last)
		LOGIF_LOCK_DESTROY();
}