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      1 /*	$NetBSD: if_gif.h,v 1.35 2020/02/01 02:57:45 riastradh Exp $	*/
      2 /*	$KAME: if_gif.h,v 1.23 2001/07/27 09:21:42 itojun Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the project nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * if_gif.h
     35  */
     36 
     37 #ifndef _NET_IF_GIF_H_
     38 #define _NET_IF_GIF_H_
     39 
     40 #include <sys/queue.h>
     41 #include <sys/percpu.h>
     42 #ifdef _KERNEL
     43 #include <sys/pserialize.h>
     44 #include <sys/psref.h>
     45 #endif
     46 
     47 #ifdef _KERNEL_OPT
     48 #include "opt_inet.h"
     49 #endif
     50 
     51 #include <netinet/in.h>
     52 /* xxx sigh, why route have struct route instead of pointer? */
     53 
     54 extern struct psref_class *gv_psref_class;
     55 
     56 struct encaptab;
     57 
     58 struct gif_variant {
     59 	struct gif_softc *gv_softc;
     60 	struct sockaddr	*gv_psrc; /* Physical src addr */
     61 	struct sockaddr	*gv_pdst; /* Physical dst addr */
     62 	const struct encaptab *gv_encap_cookie4;
     63 	const struct encaptab *gv_encap_cookie6;
     64 	int (*gv_output)(struct gif_variant *, int, struct mbuf *);
     65 
     66 	struct psref_target gv_psref;
     67 };
     68 
     69 struct gif_softc {
     70 	struct ifnet	gif_if;		/* common area - must be at the top */
     71 	percpu_t *gif_ro_percpu;	/* struct tunnel_ro */
     72 	struct gif_variant *gif_var;	/*
     73 					 * reader must use gif_getref_variant()
     74 					 * instead of direct dereference.
     75 					 */
     76 	kmutex_t gif_lock;		/* writer lock for gif_var */
     77 	pserialize_t gif_psz;
     78 
     79 	int gif_pmtu;
     80 
     81 	LIST_ENTRY(gif_softc) gif_list;	/* list of all gifs */
     82 };
     83 #define GIF_ROUTE_TTL	10
     84 
     85 #define GIF_MTU		(1280)	/* Default MTU */
     86 #define	GIF_MTU_MIN	(1280)	/* Minimum MTU */
     87 #define	GIF_MTU_MAX	(8192)	/* Maximum MTU */
     88 
     89 /*
     90  * Get gif_variant from gif_softc.
     91  *
     92  * Never return NULL by contract.
     93  * gif_variant itself is protected not to be freed by gv_psref.
     94  * Once a reader dereference sc->sc_var by this API, the reader must not
     95  * re-dereference form sc->sc_var.
     96  */
     97 static __inline struct gif_variant *
     98 gif_getref_variant(struct gif_softc *sc, struct psref *psref)
     99 {
    100 	struct gif_variant *var;
    101 	int s;
    102 
    103 	s = pserialize_read_enter();
    104 	var = atomic_load_consume(&sc->gif_var);
    105 	KASSERT(var != NULL);
    106 	psref_acquire(psref, &var->gv_psref, gv_psref_class);
    107 	pserialize_read_exit(s);
    108 
    109 	return var;
    110 }
    111 
    112 static __inline void
    113 gif_putref_variant(struct gif_variant *var, struct psref *psref)
    114 {
    115 
    116 	KASSERT(var != NULL);
    117 	psref_release(psref, &var->gv_psref, gv_psref_class);
    118 }
    119 
    120 static __inline bool
    121 gif_heldref_variant(struct gif_variant *var)
    122 {
    123 
    124 	return psref_held(&var->gv_psref, gv_psref_class);
    125 }
    126 
    127 /* Prototypes */
    128 void	gif_input(struct mbuf *, int, struct ifnet *);
    129 
    130 #ifdef GIF_ENCAPCHECK
    131 int	gif_encapcheck(struct mbuf *, int, int, void *);
    132 #endif
    133 
    134 /*
    135  * Locking notes:
    136  * + gif_softc_list is protected by gif_softcs.lock (an adaptive mutex)
    137  *       gif_softc_list is list of all gif_softcs. It is used by ioctl
    138  *       context only.
    139  * + gif_softc->gif_var is protected by
    140  *   - gif_softc->gif_lock (an adaptive mutex) for writer
    141  *   - gif_var->gv_psref for reader
    142  *       gif_softc->gif_var is used for variant values while the gif tunnel
    143  *       exists.
    144  * + Each CPU's tunnel_ro.tr_ro of gif_ro_percpu are protected by
    145  *   percpu'ed tunnel_ro.tr_lock.
    146  *
    147  * Locking order:
    148  *     - encap_lock => gif_softc->gif_lock => gif_softcs.lock
    149  */
    150 #endif /* !_NET_IF_GIF_H_ */
    151