/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* 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. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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.
*/
struct gif_softc {
struct ifnet gif_if; /* common area - must be at the top */
percpu_t *gif_ro_percpu; /* struct tunnel_ro */
struct gif_variant *gif_var; /*
* reader must use gif_getref_variant()
* instead of direct dereference.
*/
kmutex_t gif_lock; /* writer lock for gif_var */
pserialize_t gif_psz;
int gif_pmtu;
LIST_ENTRY(gif_softc) gif_list; /* list of all gifs */
};
#define GIF_ROUTE_TTL 10
#define GIF_MTU (1280) /* Default MTU */
#define GIF_MTU_MIN (1280) /* Minimum MTU */
#define GIF_MTU_MAX (8192) /* Maximum MTU */
/*
* Get gif_variant from gif_softc.
*
* Never return NULL by contract.
* gif_variant itself is protected not to be freed by gv_psref.
* Once a reader dereference sc->sc_var by this API, the reader must not
* re-dereference form sc->sc_var.
*/
static __inline struct gif_variant *
gif_getref_variant(struct gif_softc *sc, struct psref *psref)
{
struct gif_variant *var;
int s;
s = pserialize_read_enter();
var = atomic_load_consume(&sc->gif_var);
KASSERT(var != NULL);
psref_acquire(psref, &var->gv_psref, gv_psref_class);
pserialize_read_exit(s);
/*
* Locking notes:
* + gif_softc_list is protected by gif_softcs.lock (an adaptive mutex)
* gif_softc_list is list of all gif_softcs. It is used by ioctl
* context only.
* + gif_softc->gif_var is protected by
* - gif_softc->gif_lock (an adaptive mutex) for writer
* - gif_var->gv_psref for reader
* gif_softc->gif_var is used for variant values while the gif tunnel
* exists.
* + Each CPU's tunnel_ro.tr_ro of gif_ro_percpu are protected by
* percpu'ed tunnel_ro.tr_lock.
*
* Locking order:
* - encap_lock => gif_softc->gif_lock => gif_softcs.lock
*/
#endif /* !_NET_IF_GIF_H_ */
