bsd/netinet6/nd6_rti.c

   1 /*
   2  * Copyright (c) 2020 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <kern/zalloc.h>
  29 #include <net/if.h>
  30 #include <net/if_var.h>
  31 #include <netinet/in.h>
  32 #include <netinet6/in6_var.h>
  33 #include <netinet6/in6_ifattach.h>
  34 #include <netinet/ip6.h>
  35 #include <netinet6/ip6_var.h>
  36 #include <netinet6/nd6.h>
  37 #include <netinet6/scope6_var.h>
  38 #include <sys/mcache.h>
  39
  40 #define NDRTI_ZONE_NAME "nd6_route_info"        /* zone name */
  41
  42 extern lck_mtx_t *nd6_mutex;
  43 static struct nd_route_info *nd6_rti_lookup(struct nd_route_info *);
  44
  45 static ZONE_DECLARE(ndrti_zone, "nd6_route_info",
  46     sizeof(struct nd_route_info), ZC_ZFREE_CLEARMEM);
  47
  48 static boolean_t nd6_rti_list_busy = FALSE;             /* protected by nd6_mutex */
  49
  50
  51 void
  52 nd6_rti_list_wait(const char *func)
  53 {
  54         LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_OWNED);
  55         while (nd6_rti_list_busy) {
  56                 nd6log2(debug, "%s: someone else is operating "
  57                     "on rti list. Entering sleep.\n", func);
  58                 (void) msleep(&nd6_rti_list_busy, nd6_mutex, (PZERO - 1),
  59                     func, NULL);
  60                 LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_OWNED);
  61         }
  62         nd6_rti_list_busy = TRUE;
  63 }
  64
  65 void
  66 nd6_rti_list_signal_done(void)
  67 {
  68         LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_OWNED);
  69         nd6_rti_list_busy = FALSE;
  70         wakeup(&nd6_rti_list_busy);
  71 }
  72
  73 struct nd_route_info *
  74 ndrti_alloc(void)
  75 {
  76         return zalloc_flags(ndrti_zone, Z_WAITOK | Z_ZERO);
  77 }
  78
  79 void
  80 ndrti_free(struct nd_route_info *rti)
  81 {
  82         if (!TAILQ_EMPTY(&rti->nd_rti_router_list)) {
  83                 panic("%s: rti freed with non-empty router list", __func__);
  84         }
  85         zfree(ndrti_zone, rti);
  86 }
  87
  88 static struct nd_route_info *
  89 nd6_rti_lookup(struct nd_route_info *rti)
  90 {
  91         struct nd_route_info *tmp_rti = NULL;
  92
  93         LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_OWNED);
  94
  95         TAILQ_FOREACH(tmp_rti, &nd_rti_list, nd_rti_entry) {
  96                 if (IN6_ARE_ADDR_EQUAL(&tmp_rti->nd_rti_prefix, &rti->nd_rti_prefix) &&
  97                     tmp_rti->nd_rti_prefixlen == rti->nd_rti_prefixlen) {
  98                         break;
  99                 }
 100         }
 101         return tmp_rti;
 102 }
 103
 104 void
 105 nd6_rtilist_update(struct nd_route_info *new_rti, struct nd_defrouter *dr)
 106 {
 107         struct nd_route_info *rti = NULL;
 108
 109         lck_mtx_lock(nd6_mutex);
 110         VERIFY(new_rti != NULL && dr != NULL);
 111         nd6_rti_list_wait(__func__);
 112
 113         if ((rti = nd6_rti_lookup(new_rti)) != NULL) {
 114                 (void)defrtrlist_update(dr, &rti->nd_rti_router_list);
 115                 /*
 116                  * The above may have removed an entry from default router list.
 117                  * If it did and the list is now empty, remove the rti as well.
 118                  */
 119                 if (TAILQ_EMPTY(&rti->nd_rti_router_list)) {
 120                         TAILQ_REMOVE(&nd_rti_list, rti, nd_rti_entry);
 121                         ndrti_free(rti);
 122                 }
 123         } else if (dr->rtlifetime != 0) {
 124                 rti = ndrti_alloc();
 125                 TAILQ_INIT(&rti->nd_rti_router_list);
 126                 rti->nd_rti_prefix = new_rti->nd_rti_prefix;
 127                 rti->nd_rti_prefixlen = new_rti->nd_rti_prefixlen;
 128                 (void)defrtrlist_update(dr, &rti->nd_rti_router_list);
 129                 TAILQ_INSERT_HEAD(&nd_rti_list, rti, nd_rti_entry);
 130         }
 131         /* If rti doesn't exist and lifetime is 0, simply ignore */
 132         nd6_rti_list_signal_done();
 133         lck_mtx_unlock(nd6_mutex);
 134 }
 135
 136 void
 137 nd6_rti_purge(struct nd_route_info *new_rti)
 138 {
 139         VERIFY(new_rti != NULL);
 140         LCK_MTX_ASSERT(nd6_mutex, LCK_MTX_ASSERT_OWNED);
 141
 142         struct nd_route_info *rti = NULL;
 143         nd6_rti_list_wait(__func__);
 144
 145         if ((rti = nd6_rti_lookup(new_rti)) != NULL) {
 146                 struct nd_defrouter *dr = NULL;
 147                 struct nd_defrouter *ndr = NULL;
 148
 149                 TAILQ_FOREACH_SAFE(dr, &rti->nd_rti_router_list, dr_entry, ndr) {
 150                         TAILQ_REMOVE(&rti->nd_rti_router_list, dr, dr_entry);
 151                         defrtrlist_del(dr, &rti->nd_rti_router_list);
 152                         NDDR_REMREF(dr);
 153                 }
 154                 TAILQ_REMOVE(&nd_rti_list, rti, nd_rti_entry);
 155                 ndrti_free(rti);
 156         }
 157         nd6_rti_list_signal_done();
 158 }