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if_ipsec.h revision 1.4
      1 /*	$NetBSD: if_ipsec.h,v 1.4 2018/10/19 00:12:56 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  * if_ipsec.h
     31  */
     32 
     33 #ifndef _NET_IF_IPSEC_H_
     34 #define _NET_IF_IPSEC_H_
     35 
     36 #include <sys/queue.h>
     37 #ifdef _KERNEL
     38 #include <sys/pserialize.h>
     39 #include <sys/psref.h>
     40 #endif
     41 
     42 #ifdef _KERNEL_OPT
     43 #include "opt_inet.h"
     44 #endif
     45 
     46 #include <netinet/in.h>
     47 #include <netipsec/ipsec.h>
     48 
     49 #ifdef _KERNEL
     50 /*
     51  * This macro controls the upper limitation on nesting of ipsec tunnels.
     52  * Since, setting a large value to this macro with a careless configuration
     53  * may introduce system crash, we don't allow any nestings by default.
     54  * If you need to configure nested ipsec tunnels, you can define this macro
     55  * in your kernel configuration file.  However, if you do so, please be
     56  * careful to configure the tunnels so that it won't make a loop.
     57  */
     58 #ifndef MAX_IPSEC_NEST
     59 #define MAX_IPSEC_NEST 1
     60 #endif
     61 
     62 #define IFF_NAT_T	IFF_LINK0	/* enable NAT-T */
     63 #define IFF_ECN		IFF_LINK1	/* enable ECN */
     64 #define IFF_FWD_IPV6	IFF_LINK2	/* foward IPv6 packet */
     65 
     66 extern struct psref_class *iv_psref_class;
     67 
     68 struct ipsec_variant {
     69 	struct ipsec_softc *iv_softc;
     70 
     71 	struct sockaddr	*iv_psrc;	/* Physical src addr */
     72 	struct sockaddr	*iv_pdst;	/* Physical dst addr */
     73 	const struct encaptab *iv_encap_cookie4;
     74 	const struct encaptab *iv_encap_cookie6;
     75 	int (*iv_output)(struct ipsec_variant *, int, struct mbuf *);
     76 	in_port_t iv_sport;
     77 	in_port_t iv_dport;
     78 
     79 	/*
     80 	 * IPsec SPs
     81 	 * Don't change directly, use if_ipsec_replace_sp().
     82 	 */
     83 	struct secpolicy *iv_sp[IPSEC_DIR_MAX];
     84 	struct secpolicy *iv_sp6[IPSEC_DIR_MAX];
     85 
     86 	struct psref_target iv_psref;
     87 };
     88 
     89 struct ipsec_ro {
     90 	struct route ir_ro;
     91 	kmutex_t *ir_lock;
     92 };
     93 
     94 struct ipsec_softc {
     95 	struct ifnet	ipsec_if;	/* common area - must be at the top */
     96 	percpu_t *ipsec_ro_percpu;	/* struct ipsec_ro */
     97 	struct ipsec_variant *ipsec_var; /*
     98 					  * reader must use ipsec_getref_variant()
     99 					  * instead of direct dereference.
    100 					  */
    101 	kmutex_t ipsec_lock;		/* writer lock for ipsec_var */
    102 	pserialize_t ipsec_psz;
    103 
    104 	LIST_ENTRY(ipsec_softc) ipsec_list; /* list of all gifs */
    105 };
    106 
    107 #define IPSEC_MTU		(1280)	/* Default MTU */
    108 #define	IPSEC_MTU_MIN		(1280)	/* Minimum MTU */
    109 #define	IPSEC_MTU_MAX		(8192)	/* Maximum MTU */
    110 
    111 #define IV_SP_IN(x) ((x)->iv_sp[IPSEC_DIR_INBOUND])
    112 #define IV_SP_IN6(x) ((x)->iv_sp6[IPSEC_DIR_INBOUND])
    113 #define IV_SP_OUT(x) ((x)->iv_sp[IPSEC_DIR_OUTBOUND])
    114 #define IV_SP_OUT6(x) ((x)->iv_sp6[IPSEC_DIR_OUTBOUND])
    115 
    116 static __inline bool
    117 if_ipsec_variant_is_configured(struct ipsec_variant *var)
    118 {
    119 
    120 	return (var->iv_psrc != NULL && var->iv_pdst != NULL);
    121 }
    122 
    123 static __inline bool
    124 if_ipsec_variant_is_unconfigured(struct ipsec_variant *var)
    125 {
    126 
    127 	return (var->iv_psrc == NULL || var->iv_pdst == NULL);
    128 }
    129 
    130 static __inline void
    131 if_ipsec_copy_variant(struct ipsec_variant *dst, struct ipsec_variant *src)
    132 {
    133 
    134 	dst->iv_softc = src->iv_softc;
    135 	dst->iv_psrc = src->iv_psrc;
    136 	dst->iv_pdst = src->iv_pdst;
    137 	dst->iv_encap_cookie4 = src->iv_encap_cookie4;
    138 	dst->iv_encap_cookie6 = src->iv_encap_cookie6;
    139 	dst->iv_output = src->iv_output;
    140 	dst->iv_sport = src->iv_sport;
    141 	dst->iv_dport = src->iv_dport;
    142 }
    143 
    144 static __inline void
    145 if_ipsec_clear_config(struct ipsec_variant *var)
    146 {
    147 
    148 	var->iv_psrc = NULL;
    149 	var->iv_pdst = NULL;
    150 	var->iv_encap_cookie4 = NULL;
    151 	var->iv_encap_cookie6 = NULL;
    152 	var->iv_output = NULL;
    153 	var->iv_sport = 0;
    154 	var->iv_dport = 0;
    155 }
    156 
    157 /*
    158  * Get ipsec_variant from ipsec_softc.
    159  *
    160  * Never return NULL by contract.
    161  * ipsec_variant itself is protected not to be freed by lv_psref.
    162  * Once a reader dereference sc->sc_var by this API, the reader must not
    163  * re-dereference from sc->sc_var.
    164  */
    165 static __inline struct ipsec_variant *
    166 if_ipsec_getref_variant(struct ipsec_softc *sc, struct psref *psref)
    167 {
    168 	struct ipsec_variant *var;
    169 	int s;
    170 
    171 	s = pserialize_read_enter();
    172 	var = sc->ipsec_var;
    173 	KASSERT(var != NULL);
    174 	membar_datadep_consumer();
    175 	psref_acquire(psref, &var->iv_psref, iv_psref_class);
    176 	pserialize_read_exit(s);
    177 
    178 	return var;
    179 }
    180 
    181 static __inline void
    182 if_ipsec_putref_variant(struct ipsec_variant *var, struct psref *psref)
    183 {
    184 
    185 	KASSERT(var != NULL);
    186 	psref_release(psref, &var->iv_psref, iv_psref_class);
    187 }
    188 
    189 static __inline bool
    190 if_ipsec_heldref_variant(struct ipsec_variant *var)
    191 {
    192 
    193 	return psref_held(&var->iv_psref, iv_psref_class);
    194 }
    195 
    196 void ipsecifattach(int);
    197 int if_ipsec_encap_func(struct mbuf *, int, int, void *);
    198 void if_ipsec_input(struct mbuf *, int, struct ifnet *);
    199 int if_ipsec_output(struct ifnet *, struct mbuf *,
    200 		    const struct sockaddr *, const struct rtentry *);
    201 int if_ipsec_ioctl(struct ifnet *, u_long, void *);
    202 #endif /* _KERNEL */
    203 
    204 /*
    205  * sharing SP note:
    206  * When ipsec(4) I/Fs use NAT-T, they can use the same src and dst address pair
    207  * as long as they use different port. Howerver, SPD cannot have the SPs which
    208  * use the same src and dst address pair and the same policy. So, such ipsec(4)
    209  * I/Fs share the same SPs.
    210  * To avoid race between ipsec0 set_tunnel/delete_tunnel and ipsec1
    211  * t_tunnel/delete_tunnel, any global lock is needed. See also the following
    212  * locking notes.
    213  *
    214  * Locking notes:
    215  * + ipsec_softcs.list is protected by ipsec_softcs.lock (an adaptive mutex)
    216  *       ipsec_softc_list is list of all ipsec_softcs. It is used by ioctl
    217  *       context only.
    218  * + ipsec_softc->ipsec_var is protected by
    219  *   - ipsec_softc->ipsec_lock (an adaptive mutex) for writer
    220  *   - ipsec_var->iv_psref for reader
    221  *       ipsec_softc->ipsec_var is used for variant values while the ipsec tunnel
    222  *       exists.
    223  * + struct ipsec_ro->ir_ro is protected by struct ipsec_ro->ir_lock.
    224  *       This lock is required to exclude softnet/0 lwp(such as output
    225  *       processing softint) and  processing lwp(such as DAD timer processing).
    226  * + if_ipsec_share_sp() and if_ipsec_unshare_sp() operations are serialized by
    227  *   encap_lock
    228  *       This only need to be global lock, need not to be encap_lock.
    229  *
    230  * Locking order:
    231  *     - encap_lock => ipsec_softc->ipsec_lock => ipsec_softcs.lock
    232  */
    233 #endif /* _NET_IF_IPSEC_H_ */
    234