1 /* $NetBSD: if_l2tp.h,v 1.10 2021/03/16 07:00:38 knakahara Exp $ */ 2 3 /* 4 * Copyright (c) 2017 Internet Initiative Japan Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * L2TPv3 kernel interface 31 */ 32 33 #ifndef _NET_IF_L2TP_H_ 34 #define _NET_IF_L2TP_H_ 35 36 #include <sys/queue.h> 37 #include <sys/ioccom.h> 38 #ifdef _KERNEL 39 #include <sys/pserialize.h> 40 #include <sys/psref.h> 41 #include <sys/pslist.h> 42 #endif 43 44 #include <net/if_ether.h> 45 #include <netinet/in.h> 46 47 #define SIOCSL2TPSESSION _IOW('i', 151, struct ifreq) 48 #define SIOCDL2TPSESSION _IOW('i', 152, struct ifreq) 49 #define SIOCSL2TPCOOKIE _IOW('i', 153, struct ifreq) 50 #define SIOCDL2TPCOOKIE _IOW('i', 154, struct ifreq) 51 #define SIOCSL2TPSTATE _IOW('i', 155, struct ifreq) 52 #define SIOCGL2TP SIOCGIFGENERIC 53 54 struct l2tp_req { 55 int state; 56 u_int my_cookie_len; 57 u_int peer_cookie_len; 58 uint32_t my_sess_id; 59 uint32_t peer_sess_id; 60 uint64_t my_cookie; 61 uint64_t peer_cookie; 62 }; 63 64 #define L2TP_STATE_UP 1 65 #define L2TP_STATE_DOWN 0 66 67 #define L2TP_COOKIE_ON 1 68 #define L2TP_COOKIE_OFF 0 69 70 #ifdef _KERNEL 71 extern struct psref_class *lv_psref_class; 72 73 struct l2tp_variant { 74 struct l2tp_softc *lv_softc; 75 76 struct sockaddr *lv_psrc; /* Physical src addr */ 77 struct sockaddr *lv_pdst; /* Physical dst addr */ 78 const struct encaptab *lv_encap_cookie; 79 80 /* L2TP session info */ 81 int lv_state; 82 uint32_t lv_my_sess_id; /* my session ID */ 83 uint32_t lv_peer_sess_id; /* peer session ID */ 84 85 int lv_use_cookie; 86 u_int lv_my_cookie_len; 87 u_int lv_peer_cookie_len; 88 uint64_t lv_my_cookie; /* my cookie */ 89 uint64_t lv_peer_cookie; /* peer cookie */ 90 91 struct psref_target lv_psref; 92 }; 93 94 struct l2tp_softc { 95 struct ethercom l2tp_ec; /* common area - must be at the top */ 96 /* to use ether_input(), we must have this */ 97 percpu_t *l2tp_ro_percpu; /* struct tunnel_ro */ 98 struct l2tp_variant *l2tp_var; /* 99 * reader must use l2tp_getref_variant() 100 * instead of direct dereference. 101 */ 102 kmutex_t l2tp_lock; /* writer lock for l2tp_var */ 103 pserialize_t l2tp_psz; 104 105 void *l2tp_si; 106 percpu_t *l2tp_ifq_percpu; 107 108 LIST_ENTRY(l2tp_softc) l2tp_list; /* list of all l2tps */ 109 struct pslist_entry l2tp_hash; /* hashed list to lookup by session id */ 110 }; 111 112 #define L2TP_ROUTE_TTL 10 113 114 #define L2TP_MTU (1280) /* Default MTU */ 115 #define L2TP_MTU_MIN (1280) /* Minimum MTU */ 116 #define L2TP_MTU_MAX (8192) /* Maximum MTU */ 117 118 /* 119 * Get l2tp_variant from l2tp_softc. 120 * 121 * l2tp_variant itself is protected not to be freed by lv_psref. 122 * In contrast, sc->sc_var can be changed to NULL even if reader critical 123 * section. see l2tp_variant_update(). 124 * So, once a reader dereference sc->sc_var by this API, the reader must not 125 * re-dereference form sc->sc_var. 126 */ 127 static __inline struct l2tp_variant * 128 l2tp_getref_variant(struct l2tp_softc *sc, struct psref *psref) 129 { 130 struct l2tp_variant *var; 131 int s; 132 133 s = pserialize_read_enter(); 134 var = atomic_load_consume(&sc->l2tp_var); 135 if (var == NULL) { 136 pserialize_read_exit(s); 137 return NULL; 138 } 139 psref_acquire(psref, &var->lv_psref, lv_psref_class); 140 pserialize_read_exit(s); 141 142 return var; 143 } 144 145 static __inline void 146 l2tp_putref_variant(struct l2tp_variant *var, struct psref *psref) 147 { 148 149 if (var == NULL) 150 return; 151 psref_release(psref, &var->lv_psref, lv_psref_class); 152 } 153 154 static __inline bool 155 l2tp_heldref_variant(struct l2tp_variant *var) 156 { 157 158 return psref_held(&var->lv_psref, lv_psref_class); 159 } 160 161 162 /* Prototypes */ 163 void l2tpattach(int); 164 int l2tpattach0(struct l2tp_softc *); 165 void l2tp_input(struct mbuf *, struct ifnet *); 166 int l2tp_ioctl(struct ifnet *, u_long, void *); 167 168 struct l2tp_variant *l2tp_lookup_session_ref(uint32_t, struct psref *); 169 int l2tp_check_nesting(struct ifnet *, struct mbuf *); 170 171 /* TODO IP_TCPMSS support */ 172 #ifdef IP_TCPMSS 173 struct mbuf *l2tp_tcpmss_clamp(struct ifnet *, struct mbuf *); 174 #endif /* IP_TCPMSS */ 175 #endif /* _KERNEL */ 176 177 /* 178 * Locking notes: 179 * + l2tp_softc_list is protected by l2tp_list_lock (an adaptive mutex) 180 * l2tp_softc_list is list of all l2tp_softcs, and it is used to avoid 181 * unload while busy. 182 * + l2tp_hashed_list is protected by 183 * - l2tp_hash_lock (an adaptive mutex) for writer 184 * - pserialize for reader 185 * l2tp_hashed_list is hashed list of all l2tp_softcs, and it is used by 186 * input processing to find appropriate softc. 187 * + l2tp_softc->l2tp_var is protected by 188 * - l2tp_softc->l2tp_lock (an adaptive mutex) for writer 189 * - l2tp_var->lv_psref for reader 190 * l2tp_softc->l2tp_var is used for variant values while the l2tp tunnel 191 * exists. 192 * + struct l2tp_ro->lr_ro is protected by struct tunnel_ro->tr_lock. 193 * This lock is required to exclude softnet/0 lwp(such as output 194 * processing softint) and processing lwp(such as DAD timer processing). 195 * 196 * Locking order: 197 * - encap_lock => struct l2tp_softc->l2tp_lock 198 * Other mutexes must not hold simultaneously. 199 * 200 * NOTICE 201 * - l2tp_softc must not have a variant value while the l2tp tunnel exists. 202 * Such variant values must be in l2tp_softc->l2tp_var. 203 * - l2tp_softc->l2tp_var is modified like read-copy-update. 204 * So, once we dereference l2tp_softc->l2tp_var, we must 205 * keep the pointer during the same context. If we re-derefence 206 * l2tp_softc->l2tp_var, the l2tp_var may be other one because of 207 * concurrent writer processing. 208 */ 209 #endif /* _NET_IF_L2TP_H_ */ 210
Indexes created Wed Sep 24 15:09:51 GMT 2025