/*	$NetBSD: npf_ext_log.c,v 1.13 2017/02/18 23:27:32 christos Exp $	*/

/*-
 * Copyright (c) 2010-2012 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This material is based upon work partially supported by The
 * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * NPF logging extension.
 */

#ifdef _KERNEL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: npf_ext_log.c,v 1.13 2017/02/18 23:27:32 christos Exp $");

#include <sys/types.h>
#include <sys/module.h>

#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/queue.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/bpf.h>
#endif

#include "npf_impl.h"
#include "if_npflog.h"

NPF_EXT_MODULE(npf_ext_log, "");

#define	NPFEXT_LOG_VER		1

static void *		npf_ext_log_id;

typedef struct {
	unsigned int	if_idx;
} npf_ext_log_t;

static int
npf_log_ctor(npf_rproc_t *rp, prop_dictionary_t params)
{
	npf_ext_log_t *meta;

	meta = kmem_zalloc(sizeof(npf_ext_log_t), KM_SLEEP);
	prop_dictionary_get_uint32(params, "log-interface", &meta->if_idx);
	npf_rproc_assign(rp, meta);
	return 0;
}

static void
npf_log_dtor(npf_rproc_t *rp, void *meta)
{
	kmem_free(meta, sizeof(npf_ext_log_t));
}

static bool
npf_log(npf_cache_t *npc, void *meta, const npf_match_info_t *mi, int *decision)
{
	struct mbuf *m = nbuf_head_mbuf(npc->npc_nbuf);
	const npf_ext_log_t *log = meta;
	struct psref psref;
	ifnet_t *ifp;
	struct npfloghdr hdr;

	memset(&hdr, 0, sizeof(hdr));
	/* Set the address family. */
	if (npf_iscached(npc, NPC_IP4)) {
		hdr.af = AF_INET;
	} else if (npf_iscached(npc, NPC_IP6)) {
		hdr.af = AF_INET6;
	} else {
		hdr.af = AF_UNSPEC;
	}

	hdr.length = NPFLOG_REAL_HDRLEN;
	hdr.action = *decision == NPF_DECISION_PASS ?
	    0 /* pass */ : 1 /* block */;
	hdr.reason = 0;	/* match */

	struct nbuf *nb = npc->npc_nbuf;
	npf_ifmap_copyname(npc->npc_ctx, nb ? nb->nb_ifid : 0,
	    hdr.ifname, sizeof(hdr.ifname));

	hdr.rulenr = htonl((uint32_t)mi->mi_rid);
	hdr.subrulenr = htonl((uint32_t)(mi->mi_rid >> 32));
	strlcpy(hdr.ruleset, "rules", sizeof(hdr.ruleset));

	hdr.uid = UID_MAX;
	hdr.pid = (pid_t)-1;
	hdr.rule_uid = UID_MAX;
	hdr.rule_pid = (pid_t)-1;

	switch (mi->mi_di) {
	default:
	case PFIL_IN|PFIL_OUT:
		hdr.dir = 0;
		break;
	case PFIL_IN:
		hdr.dir = 1;
		break;
	case PFIL_OUT:
		hdr.dir = 2;
		break;
	}

	KERNEL_LOCK(1, NULL);

	/* Find a pseudo-interface to log. */
	ifp = if_get_byindex(log->if_idx, &psref);
	if (ifp == NULL) {
		/* No interface. */
		KERNEL_UNLOCK_ONE(NULL);
		return true;
	}

	/* Pass through BPF. */
	ifp->if_opackets++;
	ifp->if_obytes += m->m_pkthdr.len;
	if (ifp->if_bpf)
		bpf_mtap2(ifp->if_bpf, &hdr, NPFLOG_HDRLEN, m);
	if_put(ifp, &psref);

	KERNEL_UNLOCK_ONE(NULL);

	return true;
}

/*
 * Module interface.
 */
static int
npf_ext_log_modcmd(modcmd_t cmd, void *arg)
{
	static const npf_ext_ops_t npf_log_ops = {
		.version	= NPFEXT_LOG_VER,
		.ctx		= NULL,
		.ctor		= npf_log_ctor,
		.dtor		= npf_log_dtor,
		.proc		= npf_log
	};
	npf_t *npf = npf_getkernctx();
	int error;

	switch (cmd) {
	case MODULE_CMD_INIT:
		/*
		 * Initialise the NPF logging extension.
		 */
		npf_ext_log_id = npf_ext_register(npf, "log", &npf_log_ops);
		if (!npf_ext_log_id) {
			return EEXIST;
		}
		break;

	case MODULE_CMD_FINI:
		error = npf_ext_unregister(npf, npf_ext_log_id);
		if (error) {
			return error;
		}
		break;

	case MODULE_CMD_AUTOUNLOAD:
		/* Allow auto-unload only if NPF permits it. */
		return npf_autounload_p() ? 0 : EBUSY;

	default:
		return ENOTTY;
	}
	return 0;
}