NetBSD/sys/net/if_l2tp.h

210 lines
6.5 KiB
C

/* $NetBSD: if_l2tp.h,v 1.10 2021/03/16 07:00:38 knakahara Exp $ */
/*
* Copyright (c) 2017 Internet Initiative Japan Inc.
* 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.
*
* 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.
*/
/*
* L2TPv3 kernel interface
*/
#ifndef _NET_IF_L2TP_H_
#define _NET_IF_L2TP_H_
#include <sys/queue.h>
#include <sys/ioccom.h>
#ifdef _KERNEL
#include <sys/pserialize.h>
#include <sys/psref.h>
#include <sys/pslist.h>
#endif
#include <net/if_ether.h>
#include <netinet/in.h>
#define SIOCSL2TPSESSION _IOW('i', 151, struct ifreq)
#define SIOCDL2TPSESSION _IOW('i', 152, struct ifreq)
#define SIOCSL2TPCOOKIE _IOW('i', 153, struct ifreq)
#define SIOCDL2TPCOOKIE _IOW('i', 154, struct ifreq)
#define SIOCSL2TPSTATE _IOW('i', 155, struct ifreq)
#define SIOCGL2TP SIOCGIFGENERIC
struct l2tp_req {
int state;
u_int my_cookie_len;
u_int peer_cookie_len;
uint32_t my_sess_id;
uint32_t peer_sess_id;
uint64_t my_cookie;
uint64_t peer_cookie;
};
#define L2TP_STATE_UP 1
#define L2TP_STATE_DOWN 0
#define L2TP_COOKIE_ON 1
#define L2TP_COOKIE_OFF 0
#ifdef _KERNEL
extern struct psref_class *lv_psref_class;
struct l2tp_variant {
struct l2tp_softc *lv_softc;
struct sockaddr *lv_psrc; /* Physical src addr */
struct sockaddr *lv_pdst; /* Physical dst addr */
const struct encaptab *lv_encap_cookie;
/* L2TP session info */
int lv_state;
uint32_t lv_my_sess_id; /* my session ID */
uint32_t lv_peer_sess_id; /* peer session ID */
int lv_use_cookie;
u_int lv_my_cookie_len;
u_int lv_peer_cookie_len;
uint64_t lv_my_cookie; /* my cookie */
uint64_t lv_peer_cookie; /* peer cookie */
struct psref_target lv_psref;
};
struct l2tp_softc {
struct ethercom l2tp_ec; /* common area - must be at the top */
/* to use ether_input(), we must have this */
percpu_t *l2tp_ro_percpu; /* struct tunnel_ro */
struct l2tp_variant *l2tp_var; /*
* reader must use l2tp_getref_variant()
* instead of direct dereference.
*/
kmutex_t l2tp_lock; /* writer lock for l2tp_var */
pserialize_t l2tp_psz;
void *l2tp_si;
percpu_t *l2tp_ifq_percpu;
LIST_ENTRY(l2tp_softc) l2tp_list; /* list of all l2tps */
struct pslist_entry l2tp_hash; /* hashed list to lookup by session id */
};
#define L2TP_ROUTE_TTL 10
#define L2TP_MTU (1280) /* Default MTU */
#define L2TP_MTU_MIN (1280) /* Minimum MTU */
#define L2TP_MTU_MAX (8192) /* Maximum MTU */
/*
* Get l2tp_variant from l2tp_softc.
*
* l2tp_variant itself is protected not to be freed by lv_psref.
* In contrast, sc->sc_var can be changed to NULL even if reader critical
* section. see l2tp_variant_update().
* So, once a reader dereference sc->sc_var by this API, the reader must not
* re-dereference form sc->sc_var.
*/
static __inline struct l2tp_variant *
l2tp_getref_variant(struct l2tp_softc *sc, struct psref *psref)
{
struct l2tp_variant *var;
int s;
s = pserialize_read_enter();
var = atomic_load_consume(&sc->l2tp_var);
if (var == NULL) {
pserialize_read_exit(s);
return NULL;
}
psref_acquire(psref, &var->lv_psref, lv_psref_class);
pserialize_read_exit(s);
return var;
}
static __inline void
l2tp_putref_variant(struct l2tp_variant *var, struct psref *psref)
{
if (var == NULL)
return;
psref_release(psref, &var->lv_psref, lv_psref_class);
}
static __inline bool
l2tp_heldref_variant(struct l2tp_variant *var)
{
return psref_held(&var->lv_psref, lv_psref_class);
}
/* Prototypes */
void l2tpattach(int);
int l2tpattach0(struct l2tp_softc *);
void l2tp_input(struct mbuf *, struct ifnet *);
int l2tp_ioctl(struct ifnet *, u_long, void *);
struct l2tp_variant *l2tp_lookup_session_ref(uint32_t, struct psref *);
int l2tp_check_nesting(struct ifnet *, struct mbuf *);
/* TODO IP_TCPMSS support */
#ifdef IP_TCPMSS
struct mbuf *l2tp_tcpmss_clamp(struct ifnet *, struct mbuf *);
#endif /* IP_TCPMSS */
#endif /* _KERNEL */
/*
* Locking notes:
* + l2tp_softc_list is protected by l2tp_list_lock (an adaptive mutex)
* l2tp_softc_list is list of all l2tp_softcs, and it is used to avoid
* unload while busy.
* + l2tp_hashed_list is protected by
* - l2tp_hash_lock (an adaptive mutex) for writer
* - pserialize for reader
* l2tp_hashed_list is hashed list of all l2tp_softcs, and it is used by
* input processing to find appropriate softc.
* + l2tp_softc->l2tp_var is protected by
* - l2tp_softc->l2tp_lock (an adaptive mutex) for writer
* - l2tp_var->lv_psref for reader
* l2tp_softc->l2tp_var is used for variant values while the l2tp tunnel
* exists.
* + struct l2tp_ro->lr_ro is protected by struct tunnel_ro->tr_lock.
* This lock is required to exclude softnet/0 lwp(such as output
* processing softint) and processing lwp(such as DAD timer processing).
*
* Locking order:
* - encap_lock => struct l2tp_softc->l2tp_lock
* Other mutexes must not hold simultaneously.
*
* NOTICE
* - l2tp_softc must not have a variant value while the l2tp tunnel exists.
* Such variant values must be in l2tp_softc->l2tp_var.
* - l2tp_softc->l2tp_var is modified like read-copy-update.
* So, once we dereference l2tp_softc->l2tp_var, we must
* keep the pointer during the same context. If we re-derefence
* l2tp_softc->l2tp_var, the l2tp_var may be other one because of
* concurrent writer processing.
*/
#endif /* _NET_IF_L2TP_H_ */