freebsd-nq/sys/net/pfil.h
Kristof Provost effaab8861 netpfil: Introduce PFIL_FWD flag
Forwarded packets passed through PFIL_OUT, which made it difficult for
firewalls to figure out if they were forwarding or producing packets. This in
turn is an issue for pf for IPv6 fragment handling: it needs to call
ip6_output() or ip6_forward() to handle the fragments. Figuring out which was
difficult (and until now, incorrect).
Having pfil distinguish the two removes an ugly piece of code from pf.

Introduce a new variant of the netpfil callbacks with a flags variable, which
has PFIL_FWD set for forwarded packets. This allows pf to reliably work out if
a packet is forwarded.

Reviewed by:	ae, kevans
Differential Revision:	https://reviews.freebsd.org/D13715
2018-03-23 16:56:44 +00:00

132 lines
4.6 KiB
C

/* $FreeBSD$ */
/* $NetBSD: pfil.h,v 1.22 2003/06/23 12:57:08 martin Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1996 Matthew R. Green
* All rights reserved.
*
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
#ifndef _NET_PFIL_H_
#define _NET_PFIL_H_
#include <sys/systm.h>
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <net/vnet.h>
struct mbuf;
struct ifnet;
struct inpcb;
typedef int (*pfil_func_t)(void *, struct mbuf **, struct ifnet *, int,
struct inpcb *);
typedef int (*pfil_func_flags_t)(void *, struct mbuf **, struct ifnet *,
int, int, struct inpcb *);
/*
* The packet filter hooks are designed for anything to call them to
* possibly intercept the packet. Multiple filter hooks are chained
* together and after each other in the specified order.
*/
struct packet_filter_hook {
TAILQ_ENTRY(packet_filter_hook) pfil_chain;
pfil_func_t pfil_func;
pfil_func_flags_t pfil_func_flags;
void *pfil_arg;
};
#define PFIL_IN 0x00000001
#define PFIL_OUT 0x00000002
#define PFIL_WAITOK 0x00000004
#define PFIL_FWD 0x00000008
#define PFIL_ALL (PFIL_IN|PFIL_OUT)
typedef TAILQ_HEAD(pfil_chain, packet_filter_hook) pfil_chain_t;
#define PFIL_TYPE_AF 1 /* key is AF_* type */
#define PFIL_TYPE_IFNET 2 /* key is ifnet pointer */
#define PFIL_FLAG_PRIVATE_LOCK 0x01 /* Personal lock instead of global */
/*
* A pfil head is created by each protocol or packet intercept point.
* For packet is then run through the hook chain for inspection.
*/
struct pfil_head {
pfil_chain_t ph_in;
pfil_chain_t ph_out;
int ph_type;
int ph_nhooks;
#if defined( __linux__ ) || defined( _WIN32 )
rwlock_t ph_mtx;
#else
struct rmlock *ph_plock; /* Pointer to the used lock */
struct rmlock ph_lock; /* Private lock storage */
int flags;
#endif
union {
u_long phu_val;
void *phu_ptr;
} ph_un;
#define ph_af ph_un.phu_val
#define ph_ifnet ph_un.phu_ptr
LIST_ENTRY(pfil_head) ph_list;
};
VNET_DECLARE(struct rmlock, pfil_lock);
#define V_pfil_lock VNET(pfil_lock)
/* Public functions for pfil hook management by packet filters. */
struct pfil_head *pfil_head_get(int, u_long);
int pfil_add_hook_flags(pfil_func_flags_t, void *, int, struct pfil_head *);
int pfil_add_hook(pfil_func_t, void *, int, struct pfil_head *);
int pfil_remove_hook_flags(pfil_func_flags_t, void *, int, struct pfil_head *);
int pfil_remove_hook(pfil_func_t, void *, int, struct pfil_head *);
#define PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
/* Public functions to run the packet inspection by protocols. */
int pfil_run_hooks(struct pfil_head *, struct mbuf **, struct ifnet *, int,
int, struct inpcb *inp);
/* Public functions for pfil head management by protocols. */
int pfil_head_register(struct pfil_head *);
int pfil_head_unregister(struct pfil_head *);
/* Public pfil locking functions for self managed locks by packet filters. */
int pfil_try_rlock(struct pfil_head *, struct rm_priotracker *);
void pfil_rlock(struct pfil_head *, struct rm_priotracker *);
void pfil_runlock(struct pfil_head *, struct rm_priotracker *);
void pfil_wlock(struct pfil_head *);
void pfil_wunlock(struct pfil_head *);
int pfil_wowned(struct pfil_head *ph);
#endif /* _NET_PFIL_H_ */