/* $NetBSD: if_l2tp.h,v 1.6.4.2 2021/03/22 18:06:17 martin 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 #include #ifdef _KERNEL #include #include #include #endif #include #include #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 = sc->l2tp_var; if (var == NULL) { pserialize_read_exit(s); return NULL; } membar_datadep_consumer(); 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_ */