if_l2tp.h revision 1.2
1 /* $NetBSD: if_l2tp.h,v 1.2 2017/05/31 08:19:44 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/psref.h> 40 #include <sys/pslist.h> 41 #endif 42 43 #include <net/if_ether.h> 44 #include <netinet/in.h> 45 46 #define SIOCSL2TPSESSION _IOW('i', 151, struct l2tp_req) 47 #define SIOCDL2TPSESSION _IOW('i', 152, struct l2tp_req) 48 #define SIOCSL2TPCOOKIE _IOW('i', 153, struct l2tp_req) 49 #define SIOCDL2TPCOOKIE _IOW('i', 154, struct l2tp_req) 50 #define SIOCSL2TPSTATE _IOW('i', 155, struct l2tp_req) 51 #define SIOCGL2TP SIOCGIFGENERIC 52 53 struct l2tp_req { 54 int state; 55 u_int my_cookie_len; 56 u_int peer_cookie_len; 57 uint32_t my_sess_id; 58 uint32_t peer_sess_id; 59 uint64_t my_cookie; 60 uint64_t peer_cookie; 61 }; 62 63 #define L2TP_STATE_UP 1 64 #define L2TP_STATE_DOWN 0 65 66 #define L2TP_COOKIE_ON 1 67 #define L2TP_COOKIE_OFF 0 68 69 #ifdef _KERNEL 70 extern struct psref_class *lv_psref_class; 71 72 struct l2tp_variant { 73 struct l2tp_softc *lv_softc; 74 75 struct sockaddr *lv_psrc; /* Physical src addr */ 76 struct sockaddr *lv_pdst; /* Physical dst addr */ 77 const struct encaptab *lv_encap_cookie; 78 79 /* L2TP session info */ 80 int lv_state; 81 uint32_t lv_my_sess_id; /* my session ID */ 82 uint32_t lv_peer_sess_id; /* peer session ID */ 83 84 int lv_use_cookie; 85 u_int lv_my_cookie_len; 86 u_int lv_peer_cookie_len; 87 uint64_t lv_my_cookie; /* my cookie */ 88 uint64_t lv_peer_cookie; /* peer cookie */ 89 90 struct psref_target lv_psref; 91 }; 92 93 struct l2tp_ro { 94 struct route lr_ro; 95 kmutex_t lr_lock; 96 }; 97 98 struct l2tp_softc { 99 struct ethercom l2tp_ec; /* common area - must be at the top */ 100 /* to use ether_input(), we must have this */ 101 percpu_t *l2tp_ro_percpu; /* struct l2tp_ro */ 102 struct l2tp_variant *l2tp_var; /* 103 * reader must use l2tp_getref_variant() 104 * instead of direct dereference. 105 */ 106 kmutex_t l2tp_lock; /* writer lock for l2tp_var */ 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 = sc->l2tp_var; 135 if (var == NULL) { 136 pserialize_read_exit(s); 137 return NULL; 138 } 139 membar_datadep_consumer(); 140 psref_acquire(psref, &var->lv_psref, lv_psref_class); 141 pserialize_read_exit(s); 142 143 return var; 144 } 145 146 static inline void 147 l2tp_putref_variant(struct l2tp_variant *var, struct psref *psref) 148 { 149 150 if (var == NULL) 151 return; 152 psref_release(psref, &var->lv_psref, lv_psref_class); 153 } 154 155 static inline bool 156 l2tp_heldref_variant(struct l2tp_variant *var) 157 { 158 159 return psref_held(&var->lv_psref, lv_psref_class); 160 } 161 162 163 /* Prototypes */ 164 void l2tpattach(int); 165 void l2tpattach0(struct l2tp_softc *); 166 void l2tp_input(struct mbuf *, struct ifnet *); 167 int l2tp_ioctl(struct ifnet *, u_long, void *); 168 169 struct l2tp_variant *l2tp_lookup_session_ref(uint32_t, struct psref *); 170 int l2tp_check_nesting(struct ifnet *, struct mbuf *); 171 172 /* TODO IP_TCPMSS support */ 173 #ifdef IP_TCPMSS 174 struct mbuf *l2tp_tcpmss_clamp(struct ifnet *, struct mbuf *); 175 #endif /* IP_TCPMSS */ 176 #endif /* _KERNEL */ 177 178 /* 179 * Locking notes: 180 * + l2tp_softc_list is protected by l2tp_list_lock (an adaptive mutex) 181 * l2tp_softc_list is list of all l2tp_softcs, and it is used to avoid 182 * unload while busy. 183 * + l2tp_hashed_list is protected by 184 * - l2tp_hash_lock (an adaptive mutex) for writer 185 * - pserialize for reader 186 * l2tp_hashed_list is hashed list of all l2tp_softcs, and it is used by 187 * input processing to find appropriate softc. 188 * + l2tp_softc->l2tp_var is protected by 189 * - l2tp_softc->l2tp_lock (an adaptive mutex) for writer 190 * - l2tp_var->lv_psref for reader 191 * l2tp_softc->l2tp_var is used for variant values while the l2tp tunnel 192 * exists. 193 * + struct l2tp_ro->lr_ro is protected by struct l2tp_ro->lr_lock. 194 * This lock is required to exclude softnet/0 lwp(such as output 195 * processing softint) and processing lwp(such as DAD timer processing). 196 * 197 * Locking order: 198 * - encap_lock => struct l2tp_softc->l2tp_lock 199 * Other mutexes must not hold simultaneously. 200 * 201 * NOTICE 202 * - l2tp_softc must not have a variant value while the l2tp tunnel exists. 203 * Such variant values must be in l2tp_softc->l2tp_var. 204 * - l2tp_softc->l2tp_var is modified like read-copy-update. 205 * So, once we dereference l2tp_softc->l2tp_var, we must 206 * keep the pointer during the same context. If we re-derefence 207 * l2tp_softc->l2tp_var, the l2tp_var may be other one because of 208 * concurrent writer processing. 209 */ 210 #endif /* _NET_IF_L2TP_H_ */ 211
Indexes created Thu Sep 25 08:09:54 GMT 2025