if_l2tp.h revision 1.7
1 /* $NetBSD: if_l2tp.h,v 1.7 2019/09/19 04:59:42 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 l2tp_req) 48 #define SIOCDL2TPSESSION _IOW('i', 152, struct l2tp_req) 49 #define SIOCSL2TPCOOKIE _IOW('i', 153, struct l2tp_req) 50 #define SIOCDL2TPCOOKIE _IOW('i', 154, struct l2tp_req) 51 #define SIOCSL2TPSTATE _IOW('i', 155, struct l2tp_req) 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_ro { 95 struct route lr_ro; 96 kmutex_t *lr_lock; 97 }; 98 99 struct l2tp_softc { 100 struct ethercom l2tp_ec; /* common area - must be at the top */ 101 /* to use ether_input(), we must have this */ 102 percpu_t *l2tp_ro_percpu; /* struct l2tp_ro */ 103 struct l2tp_variant *l2tp_var; /* 104 * reader must use l2tp_getref_variant() 105 * instead of direct dereference. 106 */ 107 kmutex_t l2tp_lock; /* writer lock for l2tp_var */ 108 pserialize_t l2tp_psz; 109 110 void *l2tp_si; 111 percpu_t *l2tp_ifq_percpu; 112 113 LIST_ENTRY(l2tp_softc) l2tp_list; /* list of all l2tps */ 114 struct pslist_entry l2tp_hash; /* hashed list to lookup by session id */ 115 }; 116 117 #define L2TP_ROUTE_TTL 10 118 119 #define L2TP_MTU (1280) /* Default MTU */ 120 #define L2TP_MTU_MIN (1280) /* Minimum MTU */ 121 #define L2TP_MTU_MAX (8192) /* Maximum MTU */ 122 123 /* 124 * Get l2tp_variant from l2tp_softc. 125 * 126 * l2tp_variant itself is protected not to be freed by lv_psref. 127 * In contrast, sc->sc_var can be changed to NULL even if reader critical 128 * section. see l2tp_variant_update(). 129 * So, once a reader dereference sc->sc_var by this API, the reader must not 130 * re-dereference form sc->sc_var. 131 */ 132 static __inline struct l2tp_variant * 133 l2tp_getref_variant(struct l2tp_softc *sc, struct psref *psref) 134 { 135 struct l2tp_variant *var; 136 int s; 137 138 s = pserialize_read_enter(); 139 var = sc->l2tp_var; 140 if (var == NULL) { 141 pserialize_read_exit(s); 142 return NULL; 143 } 144 membar_datadep_consumer(); 145 psref_acquire(psref, &var->lv_psref, lv_psref_class); 146 pserialize_read_exit(s); 147 148 return var; 149 } 150 151 static __inline void 152 l2tp_putref_variant(struct l2tp_variant *var, struct psref *psref) 153 { 154 155 if (var == NULL) 156 return; 157 psref_release(psref, &var->lv_psref, lv_psref_class); 158 } 159 160 static __inline bool 161 l2tp_heldref_variant(struct l2tp_variant *var) 162 { 163 164 return psref_held(&var->lv_psref, lv_psref_class); 165 } 166 167 168 /* Prototypes */ 169 void l2tpattach(int); 170 int l2tpattach0(struct l2tp_softc *); 171 void l2tp_input(struct mbuf *, struct ifnet *); 172 int l2tp_ioctl(struct ifnet *, u_long, void *); 173 174 struct l2tp_variant *l2tp_lookup_session_ref(uint32_t, struct psref *); 175 int l2tp_check_nesting(struct ifnet *, struct mbuf *); 176 177 /* TODO IP_TCPMSS support */ 178 #ifdef IP_TCPMSS 179 struct mbuf *l2tp_tcpmss_clamp(struct ifnet *, struct mbuf *); 180 #endif /* IP_TCPMSS */ 181 #endif /* _KERNEL */ 182 183 /* 184 * Locking notes: 185 * + l2tp_softc_list is protected by l2tp_list_lock (an adaptive mutex) 186 * l2tp_softc_list is list of all l2tp_softcs, and it is used to avoid 187 * unload while busy. 188 * + l2tp_hashed_list is protected by 189 * - l2tp_hash_lock (an adaptive mutex) for writer 190 * - pserialize for reader 191 * l2tp_hashed_list is hashed list of all l2tp_softcs, and it is used by 192 * input processing to find appropriate softc. 193 * + l2tp_softc->l2tp_var is protected by 194 * - l2tp_softc->l2tp_lock (an adaptive mutex) for writer 195 * - l2tp_var->lv_psref for reader 196 * l2tp_softc->l2tp_var is used for variant values while the l2tp tunnel 197 * exists. 198 * + struct l2tp_ro->lr_ro is protected by struct l2tp_ro->lr_lock. 199 * This lock is required to exclude softnet/0 lwp(such as output 200 * processing softint) and processing lwp(such as DAD timer processing). 201 * 202 * Locking order: 203 * - encap_lock => struct l2tp_softc->l2tp_lock 204 * Other mutexes must not hold simultaneously. 205 * 206 * NOTICE 207 * - l2tp_softc must not have a variant value while the l2tp tunnel exists. 208 * Such variant values must be in l2tp_softc->l2tp_var. 209 * - l2tp_softc->l2tp_var is modified like read-copy-update. 210 * So, once we dereference l2tp_softc->l2tp_var, we must 211 * keep the pointer during the same context. If we re-derefence 212 * l2tp_softc->l2tp_var, the l2tp_var may be other one because of 213 * concurrent writer processing. 214 */ 215 #endif /* _NET_IF_L2TP_H_ */ 216
Indexes created Wed Sep 24 05:09:52 GMT 2025