]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/net/route.c
xnu-1228.15.4.tar.gz
[apple/xnu.git] / bsd / net / route.c
index ea463b5efb65d1adf0d91da93ad5380ac73da31c..4e4fb302ec1823fea2543e2fec5731bf7c0773f5 100644 (file)
@@ -1,16 +1,19 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
- * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * 
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
@@ -20,7 +23,7 @@
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * Copyright (c) 1980, 1986, 1991, 1993
 #include <sys/socket.h>
 #include <sys/domain.h>
 #include <sys/syslog.h>
+#include <sys/queue.h>
+#include <kern/lock.h>
+#include <kern/zalloc.h>
 
 #include <net/if.h>
 #include <net/route.h>
 
 #include <netinet/in.h>
+#include <netinet/in_var.h>
 #include <netinet/ip_mroute.h>
+#include <netinet/ip_var.h>
+
+#include <net/if_dl.h>
+
+#include <libkern/OSAtomic.h>
+#include <libkern/OSDebug.h>
 
+#include <pexpert/pexpert.h>
+
+#define        equal(a1, a2) (bcmp((caddr_t)(a1), (caddr_t)(a2), (a1)->sa_len) == 0)
 #define        SA(p) ((struct sockaddr *)(p))
 
+extern void kdp_set_gateway_mac (void *gatewaymac);
+
+extern struct domain routedomain;
 struct route_cb route_cb;
-static struct rtstat rtstat;
+__private_extern__ struct rtstat rtstat  = { 0, 0, 0, 0, 0 };
 struct radix_node_head *rt_tables[AF_MAX+1];
 
-static int     rttrash;                /* routes not in table but not freed */
+lck_mtx_t      *rt_mtx;        /*### global routing tables mutex for now */
+lck_attr_t     *rt_mtx_attr;
+lck_grp_t      *rt_mtx_grp;
+lck_grp_attr_t         *rt_mtx_grp_attr;
+
+lck_mtx_t      *route_domain_mtx;      /*### global routing tables mutex for now */
+int rttrash = 0;               /* routes not in table but not freed */
+
+static unsigned int rte_debug;
+
+/* Possible flags for rte_debug */
+#define        RTD_DEBUG       0x1     /* enable or disable rtentry debug facility */
+#define        RTD_TRACE       0x2     /* trace alloc, free and refcnt */
+#define        RTD_NO_FREE     0x4     /* don't free (good to catch corruptions) */
+
+static struct zone *rte_zone;                  /* special zone for rtentry */
+#define        RTE_ZONE_MAX            65536           /* maximum elements in zone */
+#define        RTE_ZONE_NAME           "rtentry"       /* name of rtentry zone */
+
+#define        RTD_INUSE               0xFEEDFACE      /* entry is in use */
+#define        RTD_FREED               0xDEADBEEF      /* entry is freed */
+
+#define        RTD_TRSTACK_SIZE        8               /* depth of stack trace */
+#define        RTD_REFHIST_SIZE        4               /* refcnt history size */
+
+/*
+ * Debug variant of rtentry structure.
+ */
+struct rtentry_dbg {
+       struct rtentry  rtd_entry;                      /* rtentry */
+       struct rtentry  rtd_entry_saved;                /* saved rtentry */
+       u_int32_t       rtd_inuse;                      /* in use pattern */
+       u_int16_t       rtd_refhold_cnt;                /* # of rtref */
+       u_int16_t       rtd_refrele_cnt;                /* # of rtunref */
+       /*
+        * Thread and PC stack trace up to RTD_TRSTACK_SIZE
+        * deep during alloc and free.
+        */
+       struct thread   *rtd_alloc_thread;
+       void            *rtd_alloc_stk_pc[RTD_TRSTACK_SIZE];
+       struct thread   *rtd_free_thread;
+       void            *rtd_free_stk_pc[RTD_TRSTACK_SIZE];
+       /*
+        * Circular lists of rtref and rtunref callers.
+        */
+       u_int16_t       rtd_refhold_next;
+       u_int16_t       rtd_refrele_next;
+       struct {
+               struct thread *th;
+               void *pc[RTD_TRSTACK_SIZE];
+       } rtd_refhold[RTD_REFHIST_SIZE];
+       struct {
+               struct thread *th;
+               void *pc[RTD_TRSTACK_SIZE];
+       } rtd_refrele[RTD_REFHIST_SIZE];
+       /*
+        * Trash list linkage
+        */
+       TAILQ_ENTRY(rtentry_dbg) rtd_trash_link;
+};
+
+/* List of trash route entries protected by rt_mtx */
+static TAILQ_HEAD(, rtentry_dbg) rttrash_head;
+
+static inline struct rtentry *rte_alloc_debug(void);
+static inline void rte_free_debug(struct rtentry *);
+static void rt_maskedcopy(struct sockaddr *,
+           struct sockaddr *, struct sockaddr *);
+static void rtable_init(void **);
+static inline void rtref_audit(struct rtentry_dbg *);
+static inline void rtunref_audit(struct rtentry_dbg *);
+static struct rtentry *rtalloc1_common_locked(struct sockaddr *, int, u_long,
+    unsigned int);
+static int rtrequest_common_locked(int, struct sockaddr *,
+    struct sockaddr *, struct sockaddr *, int, struct rtentry **,
+    unsigned int);
+static void rtalloc_ign_common_locked(struct route *, u_long, unsigned int);
+static inline void sa_set_ifscope(struct sockaddr *, unsigned int);
+static struct sockaddr *sin_copy(struct sockaddr_in *, struct sockaddr_in *,
+    unsigned int);
+static struct sockaddr *mask_copy(struct sockaddr *, struct sockaddr_in *,
+    unsigned int);
+static struct radix_node *node_lookup(struct sockaddr *, struct sockaddr *,
+    unsigned int);
+static struct radix_node *node_lookup_default(void);
+static int rn_match_ifscope(struct radix_node *, void *);
+static struct ifaddr *ifa_ifwithroute_common_locked(int,
+    const struct sockaddr *, const struct sockaddr *, unsigned int);
+
+__private_extern__ u_long route_generation = 0;
+extern int use_routegenid;
 
-static void rt_maskedcopy __P((struct sockaddr *,
-           struct sockaddr *, struct sockaddr *));
-static void rtable_init __P((void **));
+/*
+ * sockaddr_in with embedded interface scope; this is used internally
+ * to keep track of scoped route entries in the routing table.  The
+ * fact that such a scope is embedded in the structure is an artifact
+ * of the current implementation which could change in future.
+ */
+struct sockaddr_inifscope {
+       __uint8_t       sin_len;
+       sa_family_t     sin_family;
+       in_port_t       sin_port;
+       struct  in_addr sin_addr;
+       /*
+        * To avoid possible conflict with an overlaid sockaddr_inarp
+        * having sin_other set to SIN_PROXY, we use the first 4-bytes
+        * of sin_zero since sin_srcaddr is one of the unused fields
+        * in sockaddr_inarp.
+        */
+       union {
+               char    sin_zero[8];
+               struct {
+                       __uint32_t      ifscope;
+               } _in_index;
+       } un;
+#define        sin_ifscope     un._in_index.ifscope
+};
+
+#define        SIN(sa)         ((struct sockaddr_in *)(size_t)(sa))
+#define        SINIFSCOPE(sa)  ((struct sockaddr_inifscope *)(size_t)(sa))
+
+#define        ASSERT_SINIFSCOPE(sa) {                                         \
+       if ((sa)->sa_family != AF_INET ||                               \
+           (sa)->sa_len < sizeof (struct sockaddr_in))                 \
+               panic("%s: bad sockaddr_in %p\n", __func__, sa);        \
+}
+
+/*
+ * Argument to leaf-matching routine; at present it is scoped routing
+ * specific but can be expanded in future to include other search filters.
+ */
+struct matchleaf_arg {
+       unsigned int    ifscope;        /* interface scope */
+};
+
+/*
+ * For looking up the non-scoped default route (sockaddr instead
+ * of sockaddr_in for convenience).
+ */
+static struct sockaddr sin_def = {
+       sizeof (struct sockaddr_in), AF_INET, { 0, }
+};
+
+/*
+ * Interface index (scope) of the primary interface; determined at
+ * the time when the default, non-scoped route gets added, changed
+ * or deleted.  Protected by rt_mtx.
+ */
+static unsigned int primary_ifscope = IFSCOPE_NONE;
+
+#define        INET_DEFAULT(dst)       \
+       ((dst)->sa_family == AF_INET && SIN(dst)->sin_addr.s_addr == 0)
+
+#define        RT(r)           ((struct rtentry *)r)
+#define        RT_HOST(r)      (RT(r)->rt_flags & RTF_HOST)
+
+/*
+ * Given a route, determine whether or not it is the non-scoped default
+ * route; dst typically comes from rt_key(rt) but may be coming from
+ * a separate place when rt is in the process of being created.
+ */
+boolean_t
+rt_inet_default(struct rtentry *rt, struct sockaddr *dst)
+{
+       return (INET_DEFAULT(dst) && !(rt->rt_flags & RTF_IFSCOPE));
+}
+
+/*
+ * Set the ifscope of the primary interface; caller holds rt_mtx.
+ */
+void
+set_primary_ifscope(unsigned int ifscope)
+{
+       primary_ifscope = ifscope;
+}
+
+/*
+ * Return the ifscope of the primary interface; caller holds rt_mtx.
+ */
+unsigned int
+get_primary_ifscope(void)
+{
+       return (primary_ifscope);
+}
+
+/*
+ * Embed ifscope into a given a sockaddr_in.
+ */
+static inline void
+sa_set_ifscope(struct sockaddr *sa, unsigned int ifscope)
+{
+       /* Caller must pass in sockaddr_in */
+       ASSERT_SINIFSCOPE(sa);
+
+       SINIFSCOPE(sa)->sin_ifscope = ifscope;
+}
+
+/*
+ * Given a sockaddr_in, return the embedded ifscope to the caller.
+ */
+unsigned int
+sa_get_ifscope(struct sockaddr *sa)
+{
+       /* Caller must pass in sockaddr_in */
+       ASSERT_SINIFSCOPE(sa);
+
+       return (SINIFSCOPE(sa)->sin_ifscope);
+}
+
+/*
+ * Copy a sockaddr_in src to dst and embed ifscope into dst.
+ */
+static struct sockaddr *
+sin_copy(struct sockaddr_in *src, struct sockaddr_in *dst, unsigned int ifscope)
+{
+       *dst = *src;
+       sa_set_ifscope(SA(dst), ifscope);
+
+       return (SA(dst));
+}
+
+/*
+ * Copy a mask from src to a sockaddr_in dst and embed ifscope into dst.
+ */
+static struct sockaddr *
+mask_copy(struct sockaddr *src, struct sockaddr_in *dst, unsigned int ifscope)
+{
+       /* We know dst is at least the size of sockaddr{_in} */
+       bzero(dst, sizeof (*dst));
+       rt_maskedcopy(src, SA(dst), src);
+
+       /*
+        * The length of the mask sockaddr would need to be adjusted
+        * to cover the additional sin_ifscope field; when ifscope is
+        * IFSCOPE_NONE, we'd end up clearing the embedded ifscope on
+        * the destination mask in addition to extending the length
+        * of the sockaddr, as a side effect.  This is okay, as any
+        * trailing zeroes would be skipped by rn_addmask prior to
+        * inserting or looking up the mask in the mask tree.
+        */
+       SINIFSCOPE(dst)->sin_ifscope = ifscope;
+       SINIFSCOPE(dst)->sin_len =
+           offsetof(struct sockaddr_inifscope, sin_ifscope) +
+           sizeof (SINIFSCOPE(dst)->sin_ifscope);
+
+       return (SA(dst));
+}
+
+/*
+ * Callback leaf-matching routine for rn_matchaddr_args used
+ * for looking up an exact match for a scoped route entry.
+ */
+static int
+rn_match_ifscope(struct radix_node *rn, void *arg)
+{
+       struct rtentry *rt = (struct rtentry *)rn;
+       struct matchleaf_arg *ma = arg;
+
+       if (!(rt->rt_flags & RTF_IFSCOPE) || rt_key(rt)->sa_family != AF_INET)
+               return (0);
+
+       return (SINIFSCOPE(rt_key(rt))->sin_ifscope == ma->ifscope);
+}
 
 static void
-rtable_init(table)
-       void **table;
+rtable_init(void **table)
 {
        struct domain *dom;
        for (dom = domains; dom; dom = dom->dom_next)
@@ -96,163 +372,262 @@ rtable_init(table)
 }
 
 void
-route_init()
+route_init(void)
 {
+       int size;
+
+       PE_parse_boot_argn("rte_debug", &rte_debug, sizeof (rte_debug));
+       if (rte_debug != 0)
+               rte_debug |= RTD_DEBUG;
+
+       rt_mtx_grp_attr = lck_grp_attr_alloc_init();
+
+       rt_mtx_grp = lck_grp_alloc_init("route", rt_mtx_grp_attr);
+
+       rt_mtx_attr = lck_attr_alloc_init();
+
+       if ((rt_mtx = lck_mtx_alloc_init(rt_mtx_grp, rt_mtx_attr)) == NULL) {
+               printf("route_init: can't alloc rt_mtx\n");
+               return;
+       }
+
+       lck_mtx_lock(rt_mtx);
        rn_init();      /* initialize all zeroes, all ones, mask table */
+       lck_mtx_unlock(rt_mtx);
        rtable_init((void **)rt_tables);
+       route_domain_mtx = routedomain.dom_mtx;
+
+       if (rte_debug & RTD_DEBUG)
+               size = sizeof (struct rtentry_dbg);
+       else
+               size = sizeof (struct rtentry);
+
+       rte_zone = zinit(size, RTE_ZONE_MAX * size, 0, RTE_ZONE_NAME);
+       if (rte_zone == NULL)
+               panic("route_init: failed allocating rte_zone");
+
+       zone_change(rte_zone, Z_EXPAND, TRUE);
+
+       TAILQ_INIT(&rttrash_head);
 }
 
 /*
  * Packet routing routines.
  */
 void
-rtalloc(ro)
-       register struct route *ro;
+rtalloc(struct route *ro)
 {
        rtalloc_ign(ro, 0UL);
 }
 
 void
-rtalloc_ign(ro, ignore)
-       register struct route *ro;
-       u_long ignore;
+rtalloc_ign_locked(struct route *ro, u_long ignore)
+{
+       return (rtalloc_ign_common_locked(ro, ignore, IFSCOPE_NONE));
+}
+
+void
+rtalloc_scoped_ign_locked(struct route *ro, u_long ignore, unsigned int ifscope)
+{
+       return (rtalloc_ign_common_locked(ro, ignore, ifscope));
+}
+
+static void
+rtalloc_ign_common_locked(struct route *ro, u_long ignore,
+    unsigned int ifscope)
 {
        struct rtentry *rt;
-       int s;
 
        if ((rt = ro->ro_rt) != NULL) {
                if (rt->rt_ifp != NULL && rt->rt_flags & RTF_UP)
                        return;
-               /* XXX - We are probably always at splnet here already. */
-               s = splnet();
-               rtfree(rt);
+               rtfree_locked(rt);
                ro->ro_rt = NULL;
-               splx(s);
        }
-       ro->ro_rt = rtalloc1(&ro->ro_dst, 1, ignore);
+       ro->ro_rt = rtalloc1_common_locked(&ro->ro_dst, 1, ignore, ifscope);
+       if (ro->ro_rt)
+               ro->ro_rt->generation_id = route_generation;
+}
+void
+rtalloc_ign(struct route *ro, u_long ignore)
+{
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);
+       rtalloc_ign_locked(ro, ignore);
+       lck_mtx_unlock(rt_mtx);
+}
+
+struct rtentry *
+rtalloc1_locked(struct sockaddr *dst, int report, u_long ignflags)
+{
+       return (rtalloc1_common_locked(dst, report, ignflags, IFSCOPE_NONE));
+}
+
+struct rtentry *
+rtalloc1_scoped_locked(struct sockaddr *dst, int report, u_long ignflags,
+    unsigned int ifscope)
+{
+       return (rtalloc1_common_locked(dst, report, ignflags, ifscope));
 }
 
 /*
  * Look up the route that matches the address given
  * Or, at least try.. Create a cloned route if needed.
  */
-struct rtentry *
-rtalloc1(dst, report, ignflags)
-       register struct sockaddr *dst;
-       int report;
-       u_long ignflags;
+static struct rtentry *
+rtalloc1_common_locked(struct sockaddr *dst, int report, u_long ignflags,
+    unsigned int ifscope)
 {
-       register struct radix_node_head *rnh = rt_tables[dst->sa_family];
-       register struct rtentry *rt;
-       register struct radix_node *rn;
-       struct rtentry *newrt = 0;
+       struct radix_node_head *rnh = rt_tables[dst->sa_family];
+       struct rtentry *rt, *newrt = NULL;
        struct rt_addrinfo info;
        u_long nflags;
-       int  s = splnet(), err = 0, msgtype = RTM_MISS;
+       int  err = 0, msgtype = RTM_MISS;
+
+       if (rnh == NULL)
+               goto unreachable;
 
        /*
-        * Look up the address in the table for that Address Family
+        * Find the longest prefix or exact (in the scoped case) address match;
+        * callee adds a reference to entry and checks for root node as well
         */
-       if (rnh && (rn = rnh->rnh_matchaddr((caddr_t)dst, rnh)) &&
-           ((rn->rn_flags & RNF_ROOT) == 0)) {
+       rt = rt_lookup(FALSE, dst, NULL, rnh, ifscope);
+       if (rt == NULL)
+               goto unreachable;
+
+       newrt = rt;
+       nflags = rt->rt_flags & ~ignflags;
+       if (report && (nflags & (RTF_CLONING | RTF_PRCLONING))) {
                /*
-                * If we find it and it's not the root node, then
-                * get a refernce on the rtentry associated.
+                * We are apparently adding (report = 0 in delete).
+                * If it requires that it be cloned, do so.
+                * (This implies it wasn't a HOST route.)
                 */
-               newrt = rt = (struct rtentry *)rn;
-               nflags = rt->rt_flags & ~ignflags;
-               if (report && (nflags & (RTF_CLONING | RTF_PRCLONING))) {
+               err = rtrequest_locked(RTM_RESOLVE, dst, NULL, NULL, 0, &newrt);
+               if (err) {
                        /*
-                        * We are apparently adding (report = 0 in delete).
-                        * If it requires that it be cloned, do so.
-                        * (This implies it wasn't a HOST route.)
+                        * If the cloning didn't succeed, maybe what we
+                        * have from lookup above will do.  Return that;
+                        * no need to hold another reference since it's
+                        * already done.
                         */
-                       err = rtrequest(RTM_RESOLVE, dst, SA(0),
-                                             SA(0), 0, &newrt);
-                       if (err) {
-                               /*
-                                * If the cloning didn't succeed, maybe
-                                * what we have will do. Return that.
-                                */
-                               newrt = rt;
-                               rtref(rt);
-                               goto miss;
-                       }
-                       if ((rt = newrt) && (rt->rt_flags & RTF_XRESOLVE)) {
-                               /*
-                                * If the new route specifies it be
-                                * externally resolved, then go do that.
-                                */
-                               msgtype = RTM_RESOLVE;
-                               goto miss;
-                       }
-               } else
-                       rtref(rt);
-       } else {
+                       newrt = rt;
+                       goto miss;
+               }
+
                /*
-                * Either we hit the root or couldn't find any match,
-                * Which basically means
-                * "caint get there frm here"
+                * We cloned it; drop the original route found during lookup.
+                * The resulted cloned route (newrt) would now have an extra
+                * reference held during rtrequest.
                 */
-               rtstat.rts_unreach++;
-       miss:   if (report) {
+               rtfree_locked(rt);
+               if ((rt = newrt) && (rt->rt_flags & RTF_XRESOLVE)) {
                        /*
-                        * If required, report the failure to the supervising
-                        * Authorities.
-                        * For a delete, this is not an error. (report == 0)
+                        * If the new route specifies it be
+                        * externally resolved, then go do that.
                         */
-                       bzero((caddr_t)&info, sizeof(info));
-                       info.rti_info[RTAX_DST] = dst;
-                       rt_missmsg(msgtype, &info, 0, err);
+                       msgtype = RTM_RESOLVE;
+                       goto miss;
                }
        }
-       splx(s);
+       goto done;
+
+unreachable:
+       /*
+        * Either we hit the root or couldn't find any match,
+        * Which basically means "cant get there from here"
+        */
+       rtstat.rts_unreach++;
+miss:
+       if (report) {
+               /*
+                * If required, report the failure to the supervising
+                * Authorities.
+                * For a delete, this is not an error. (report == 0)
+                */
+               bzero((caddr_t)&info, sizeof(info));
+               info.rti_info[RTAX_DST] = dst;
+               rt_missmsg(msgtype, &info, 0, err);
+       }
+done:
        return (newrt);
 }
 
+struct rtentry *
+rtalloc1(struct sockaddr *dst, int report, u_long ignflags)
+{
+       struct rtentry * entry;
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);
+       entry = rtalloc1_locked(dst, report, ignflags);
+       lck_mtx_unlock(rt_mtx);
+       return (entry);
+}
+
 /*
  * Remove a reference count from an rtentry.
  * If the count gets low enough, take it out of the routing table
  */
 void
-rtfree(rt)
-       register struct rtentry *rt;
+rtfree_locked(struct rtentry *rt)
 {
        /*
         * find the tree for that address family
+        * Note: in the case of igmp packets, there might not be an rnh
         */
-       register struct radix_node_head *rnh =
-               rt_tables[rt_key(rt)->sa_family];
+       struct radix_node_head *rnh;
 
-       if (rt == 0 || rnh == 0)
-               panic("rtfree");
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       /* See 3582620 - We hit this during the transition from funnels to locks */
+       if (rt == 0) {
+               printf("rtfree - rt is NULL\n");
+               return;
+       }
+       
+       rnh = rt_tables[rt_key(rt)->sa_family];
 
        /*
         * decrement the reference count by one and if it reaches 0,
         * and there is a close function defined, call the close function
         */
-       rt->rt_refcnt--;
-       if(rnh->rnh_close && rt->rt_refcnt == 0) {
+       rtunref(rt);
+       if (rt->rt_refcnt > 0)
+               return;
+
+       /*
+        * On last reference give the "close method" a chance to cleanup
+        * private state.  This also permits (for IPv4 and IPv6) a chance
+        * to decide if the routing table entry should be purged immediately
+        * or at a later time.  When an immediate purge is to happen the
+        * close routine typically issues RTM_DELETE which clears the RTF_UP
+        * flag on the entry so that the code below reclaims the storage.
+        */
+       if (rnh && rnh->rnh_close && rt->rt_refcnt == 0)
                rnh->rnh_close((struct radix_node *)rt, rnh);
-       }
 
        /*
         * If we are no longer "up" (and ref == 0)
         * then we can free the resources associated
         * with the route.
         */
-       if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0) {
+       if (!(rt->rt_flags & RTF_UP)) {
                if (rt->rt_nodes->rn_flags & (RNF_ACTIVE | RNF_ROOT))
                        panic ("rtfree 2");
                /*
                 * the rtentry must have been removed from the routing table
                 * so it is represented in rttrash.. remove that now.
                 */
-               rttrash--;
+               (void) OSDecrementAtomic((SInt32 *)&rttrash);
+               if (rte_debug & RTD_DEBUG) {
+                       TAILQ_REMOVE(&rttrash_head, (struct rtentry_dbg *)rt,
+                           rtd_trash_link);
+               }
 
 #ifdef DIAGNOSTIC
                if (rt->rt_refcnt < 0) {
-                       printf("rtfree: %p not freed (neg refs)\n", rt);
+                       printf("rtfree: %p not freed (neg refs) cnt=%d\n",
+                           rt, rt->rt_refcnt);
                        return;
                }
 #endif
@@ -262,20 +637,11 @@ rtfree(rt)
                 * e.g other routes and ifaddrs.
                 */
                if (rt->rt_parent)
-                       rtfree(rt->rt_parent);
+                       rtfree_locked(rt->rt_parent);
 
-               if(rt->rt_ifa && !(rt->rt_parent && rt->rt_parent->rt_ifa == rt->rt_ifa)) {
-                       /*
-                        * Only release the ifa if our parent doesn't hold it for us.
-                        * The parent route is responsible for holding a reference
-                        * to the ifa for us. Ifa refcounts are 16bit, if every
-                        * cloned route held a reference, the 16bit refcount may
-                        * rollover, making a mess :(
-                        *
-                        * FreeBSD solved this by making the ifa_refcount 32bits, but
-                        * we can't do that since it changes the size of the ifaddr struct.
-                        */
+               if(rt->rt_ifa) {
                        ifafree(rt->rt_ifa);
+                       rt->rt_ifa = NULL;
                }
 
                /*
@@ -283,42 +649,98 @@ rtfree(rt)
                 * This also frees the gateway, as they are always malloc'd
                 * together.
                 */
-               Free(rt_key(rt));
+               R_Free(rt_key(rt));
 
                /*
                 * and the rtentry itself of course
                 */
-               Free(rt);
+               rte_free(rt);
        }
 }
 
+void
+rtfree(struct rtentry *rt)
+{
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);   
+       rtfree_locked(rt);
+       lck_mtx_unlock(rt_mtx);
+}
+
 /*
  * Decrements the refcount but does not free the route when
  * the refcount reaches zero. Unless you have really good reason,
  * use rtfree not rtunref.
  */
 void
-rtunref(struct rtentry* rt)
+rtunref(struct rtentry *p)
 {
-       if (rt == NULL)
-               panic("rtunref");
-       rt->rt_refcnt--;
-#if DEBUG
-       if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0)
-               printf("rtunref - if rtfree were called, we would have freed route\n");
-#endif
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       if (p->rt_refcnt <= 0)
+               panic("rtunref: bad refcnt %d for rt=%p\n", p->rt_refcnt, p);
+
+       if (rte_debug & RTD_DEBUG)
+               rtunref_audit((struct rtentry_dbg *)p);
+
+       p->rt_refcnt--;
+}
+
+static inline void
+rtunref_audit(struct rtentry_dbg *rte)
+{
+       if (rte->rtd_inuse != RTD_INUSE)
+               panic("rtunref: on freed rte=%p\n", rte);
+
+       rte->rtd_refrele_cnt++;
+
+       if (rte_debug & RTD_TRACE) {
+               rte->rtd_refrele[rte->rtd_refrele_next].th = current_thread();
+               bzero(rte->rtd_refrele[rte->rtd_refrele_next].pc,
+                   sizeof (rte->rtd_refrele[rte->rtd_refrele_next].pc));
+               (void) OSBacktrace(rte->rtd_refrele[rte->rtd_refrele_next].pc,
+                   RTD_TRSTACK_SIZE);
+
+               rte->rtd_refrele_next =
+                   (rte->rtd_refrele_next + 1) % RTD_REFHIST_SIZE;
+       }
 }
 
 /*
  * Add a reference count from an rtentry.
  */
 void
-rtref(struct rtentry* rt)
+rtref(struct rtentry *p)
 {
-       if (rt == NULL)
-               panic("rtref");
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       if (p->rt_refcnt < 0)
+               panic("rtref: bad refcnt %d for rt=%p\n", p->rt_refcnt, p);
+
+       if (rte_debug & RTD_DEBUG)
+               rtref_audit((struct rtentry_dbg *)p);
+
+       p->rt_refcnt++;
+}
+
+static inline void
+rtref_audit(struct rtentry_dbg *rte)
+{
+       if (rte->rtd_inuse != RTD_INUSE)
+               panic("rtref_audit: on freed rte=%p\n", rte);
+
+       rte->rtd_refhold_cnt++;
 
-       rt->rt_refcnt++;
+       if (rte_debug & RTD_TRACE) {
+               rte->rtd_refhold[rte->rtd_refhold_next].th = current_thread();
+               bzero(rte->rtd_refhold[rte->rtd_refhold_next].pc,
+                   sizeof (rte->rtd_refhold[rte->rtd_refhold_next].pc));
+               (void) OSBacktrace(rte->rtd_refhold[rte->rtd_refhold_next].pc,
+                   RTD_TRSTACK_SIZE);
+
+               rte->rtd_refhold_next =
+                   (rte->rtd_refhold_next + 1) % RTD_REFHIST_SIZE;
+       }
 }
 
 void
@@ -330,99 +752,109 @@ rtsetifa(struct rtentry *rt, struct ifaddr* ifa)
        if (rt->rt_ifa == ifa)
                return;
 
-       /* Release the old ifa if it isn't our parent route's ifa */
-       if (rt->rt_ifa && !(rt->rt_parent && rt->rt_parent->rt_ifa == rt->rt_ifa))
+       /* Release the old ifa */
+       if (rt->rt_ifa)
                ifafree(rt->rt_ifa);
 
        /* Set rt_ifa */
        rt->rt_ifa = ifa;
 
-       /* Take a reference to the ifa if it isn't our parent route's ifa */
-       if (rt->rt_ifa && !(rt->rt_parent && rt->rt_parent->rt_ifa == ifa))
+       /* Take a reference to the ifa */
+       if (rt->rt_ifa)
                ifaref(rt->rt_ifa);
 }
 
 void
-ifafree(ifa)
-       register struct ifaddr *ifa;
+ifafree(struct ifaddr *ifa)
 {
+       int oldval;
+
        if (ifa == NULL)
                panic("ifafree");
-       if (ifa->ifa_refcnt == 0) {
-#ifdef __APPLE__
-               /* Detect case where an ifa is being freed before it should */
-               struct ifnet* ifp;
-               /* Verify this ifa isn't attached to an interface */
-               for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next) {
-                       struct ifaddr *ifaInUse;
-                       for (ifaInUse = ifp->if_addrhead.tqh_first; ifaInUse; ifaInUse = ifaInUse->ifa_link.tqe_next) {
-                               if (ifa == ifaInUse) {
-                                       /*
-                                        * This is an ugly hack done because we can't move to a 32 bit
-                                        * refcnt like bsd has. We have to maintain binary compatibility
-                                        * in our kernel, unlike FreeBSD.
-                                        */
-                                       log(LOG_ERR, "ifa attached to ifp is being freed, leaking insted\n");
-                                       return;
-                               }
-                       }
+
+       oldval = OSAddAtomic(-1, (SInt32 *)&ifa->ifa_refcnt);
+
+       if (oldval == 0) {
+               if  ((ifa->ifa_debug & IFA_ATTACHED) != 0) {
+                       panic("ifa attached to ifp is being freed\n");
                }
-#endif
                FREE(ifa, M_IFADDR);
        }
-       else
-               ifa->ifa_refcnt--;
 }
 
-#ifdef __APPLE__
 void
 ifaref(struct ifaddr *ifa)
 {
        if (ifa == NULL)
                panic("ifaref");
-       ifa->ifa_refcnt++;
+
+       if (OSAddAtomic(1, (SInt32 *)&ifa->ifa_refcnt) == 0xffffffff)
+               panic("ifaref - reference count rolled over!");
 }
-#endif
 
 /*
  * Force a routing table entry to the specified
  * destination to go through the given gateway.
  * Normally called as a result of a routing redirect
  * message from the network layer.
- *
- * N.B.: must be called at splnet
- *
  */
 void
-rtredirect(dst, gateway, netmask, flags, src, rtp)
-       struct sockaddr *dst, *gateway, *netmask, *src;
-       int flags;
-       struct rtentry **rtp;
+rtredirect(struct ifnet *ifp, struct sockaddr *dst, struct sockaddr *gateway,
+   struct sockaddr *netmask, int flags, struct sockaddr *src,
+   struct rtentry **rtp)
 {
-       register struct rtentry *rt;
+       struct rtentry *rt = NULL;
        int error = 0;
        short *stat = 0;
        struct rt_addrinfo info;
-       struct ifaddr *ifa;
+       struct ifaddr *ifa = NULL;
+       unsigned int ifscope = (ifp != NULL) ? ifp->if_index : IFSCOPE_NONE;
+       struct sockaddr_in sin;
+
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);
 
-       /* verify the gateway is directly reachable */
-       if ((ifa = ifa_ifwithnet(gateway)) == 0) {
+       /*
+        * Verify the gateway is directly reachable; if scoped routing
+        * is enabled, verify that it is reachable from the interface
+        * where the ICMP redirect arrived on.
+        */
+       if ((ifa = ifa_ifwithnet_scoped(gateway, ifscope)) == NULL) {
                error = ENETUNREACH;
                goto out;
        }
-       rt = rtalloc1(dst, 0, 0UL);
+
+       /* Lookup route to the destination (from the original IP header) */
+       rt = rtalloc1_scoped_locked(dst, 0, RTF_CLONING|RTF_PRCLONING, ifscope);
+
+       /* Embed scope in src for comparison against rt_gateway below */
+       if (ip_doscopedroute && src->sa_family == AF_INET)
+               src = sin_copy(SIN(src), &sin, ifscope);
+
        /*
         * If the redirect isn't from our current router for this dst,
         * it's either old or wrong.  If it redirects us to ourselves,
         * we have a routing loop, perhaps as a result of an interface
         * going down recently.
         */
-#define        equal(a1, a2) (bcmp((caddr_t)(a1), (caddr_t)(a2), (a1)->sa_len) == 0)
        if (!(flags & RTF_DONE) && rt &&
-            (!equal(src, rt->rt_gateway) || rt->rt_ifa != ifa))
+            (!equal(src, rt->rt_gateway) || !equal(rt->rt_ifa->ifa_addr,
+            ifa->ifa_addr))) {
                error = EINVAL;
-       else if (ifa_ifwithaddr(gateway))
-               error = EHOSTUNREACH;
+       } else {
+               ifafree(ifa);
+               if ((ifa = ifa_ifwithaddr(gateway))) {
+                       ifafree(ifa);
+                       ifa = NULL;
+                       error = EHOSTUNREACH;
+               }
+       }
+       
+       if (ifa) {
+               ifafree(ifa);
+               ifa = NULL;
+       }
+       
        if (error)
                goto done;
        /*
@@ -441,13 +873,14 @@ rtredirect(dst, gateway, netmask, flags, src, rtp)
                if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
                        /*
                         * Changing from route to net => route to host.
-                        * Create new route, rather than smashing route to net.
+                        * Create new route, rather than smashing route
+                        * to net; similar to cloned routes, the newly
+                        * created host route is scoped as well.
                         */
                create:
                        flags |=  RTF_GATEWAY | RTF_DYNAMIC;
-                       error = rtrequest((int)RTM_ADD, dst, gateway,
-                                   netmask, flags,
-                                   (struct rtentry **)0);
+                       error = rtrequest_scoped_locked(RTM_ADD, dst,
+                           gateway, netmask, flags, NULL, ifscope);
                        stat = &rtstat.rts_dynamic;
                } else {
                        /*
@@ -460,58 +893,108 @@ rtredirect(dst, gateway, netmask, flags, src, rtp)
                        /*
                         * add the key and gateway (in one malloc'd chunk).
                         */
-                       rt_setgate(rt, rt_key(rt), gateway);
+                       error = rt_setgate(rt, rt_key(rt), gateway);
                }
-       } else
+       } else {
                error = EHOSTUNREACH;
+       }
 done:
        if (rt) {
                if (rtp && !error)
                        *rtp = rt;
                else
-                       rtfree(rt);
+                       rtfree_locked(rt);
        }
 out:
-       if (error)
+       if (error) {
                rtstat.rts_badredirect++;
-       else if (stat != NULL)
-               (*stat)++;
+       } else {
+               if (stat != NULL)
+                       (*stat)++;
+               if (use_routegenid)
+                       route_generation++;
+       }
        bzero((caddr_t)&info, sizeof(info));
        info.rti_info[RTAX_DST] = dst;
        info.rti_info[RTAX_GATEWAY] = gateway;
        info.rti_info[RTAX_NETMASK] = netmask;
        info.rti_info[RTAX_AUTHOR] = src;
        rt_missmsg(RTM_REDIRECT, &info, flags, error);
+       lck_mtx_unlock(rt_mtx);
 }
 
 /*
 * Routing table ioctl interface.
 */
 int
-rtioctl(req, data, p)
-       int req;
-       caddr_t data;
-       struct proc *p;
+rtioctl(int req, caddr_t data, struct proc *p)
 {
-#if INET
-       /* Multicast goop, grrr... */
-#if MROUTING
+#pragma unused(p)
+#if INET && MROUTING
        return mrt_ioctl(req, data);
 #else
-       return mrt_ioctl(req, data, p);
-#endif
-#else /* INET */
        return ENXIO;
-#endif /* INET */
+#endif
+}
+
+struct ifaddr *
+ifa_ifwithroute(
+       int flags,
+       const struct sockaddr   *dst,
+       const struct sockaddr *gateway)
+{
+       struct ifaddr *ifa;
+
+       lck_mtx_lock(rt_mtx);
+       ifa = ifa_ifwithroute_locked(flags, dst, gateway);
+       lck_mtx_unlock(rt_mtx);
+
+       return (ifa);
 }
 
 struct ifaddr *
-ifa_ifwithroute(flags, dst, gateway)
-       int flags;
-       struct sockaddr *dst, *gateway;
+ifa_ifwithroute_locked(int flags, const struct sockaddr *dst,
+    const struct sockaddr *gateway)
 {
-       register struct ifaddr *ifa;
-       if ((flags & RTF_GATEWAY) == 0) {
+       return (ifa_ifwithroute_common_locked((flags & ~RTF_IFSCOPE), dst,
+           gateway, IFSCOPE_NONE));
+}
+
+struct ifaddr *
+ifa_ifwithroute_scoped_locked(int flags, const struct sockaddr *dst,
+    const struct sockaddr *gateway, unsigned int ifscope)
+{
+       if (ifscope != IFSCOPE_NONE)
+               flags |= RTF_IFSCOPE;
+       else
+               flags &= ~RTF_IFSCOPE;
+
+       return (ifa_ifwithroute_common_locked(flags, dst, gateway, ifscope));
+}
+
+static struct ifaddr *
+ifa_ifwithroute_common_locked(int flags, const struct sockaddr *dst,
+    const struct sockaddr *gateway, unsigned int ifscope)
+{
+       struct ifaddr *ifa = NULL;
+       struct rtentry *rt = NULL;
+       struct sockaddr_in dst_in, gw_in;
+
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       if (ip_doscopedroute) {
+               /*
+                * Just in case the sockaddr passed in by the caller
+                * contains embedded scope, make sure to clear it since
+                * IPv4 interface addresses aren't scoped.
+                */
+               if (dst != NULL && dst->sa_family == AF_INET)
+                       dst = sin_copy(SIN(dst), &dst_in, IFSCOPE_NONE);
+               if (gateway != NULL && gateway->sa_family == AF_INET)
+                       gateway = sin_copy(SIN(gateway), &gw_in, IFSCOPE_NONE);
+       }
+
+       if (!(flags & RTF_GATEWAY)) {
                /*
                 * If we are adding a route to an interface,
                 * and the interface is a pt to pt link
@@ -519,12 +1002,11 @@ ifa_ifwithroute(flags, dst, gateway)
                 * as our clue to the interface.  Otherwise
                 * we can use the local address.
                 */
-               ifa = 0;
                if (flags & RTF_HOST) {
                        ifa = ifa_ifwithdstaddr(dst);
                }
-               if (ifa == 0)
-                       ifa = ifa_ifwithaddr(gateway);
+               if (ifa == NULL)
+                       ifa = ifa_ifwithaddr_scoped(gateway, ifscope);
        } else {
                /*
                 * If we are adding a route to a remote net
@@ -533,22 +1015,59 @@ ifa_ifwithroute(flags, dst, gateway)
                 */
                ifa = ifa_ifwithdstaddr(gateway);
        }
-       if (ifa == 0)
-               ifa = ifa_ifwithnet(gateway);
-       if (ifa == 0) {
-               struct rtentry *rt = rtalloc1(dst, 0, 0UL);
-               if (rt == 0)
-                       return (0);
+       if (ifa == NULL)
+               ifa = ifa_ifwithnet_scoped(gateway, ifscope);
+       if (ifa == NULL) {
+               /* Workaround to avoid gcc warning regarding const variable */
+               rt = rtalloc1_scoped_locked((struct sockaddr *)(size_t)dst,
+                   0, 0UL, ifscope);
+               if (rt != NULL) {
+                       ifa = rt->rt_ifa;
+                       if (ifa != NULL)
+                               ifaref(ifa);
+                       rtunref(rt);
+                       rt = NULL;
+               }
+       }
+       if (ifa != NULL && ifa->ifa_addr->sa_family != dst->sa_family) {
+               struct ifaddr *newifa;
+               /* Callee adds reference to newifa upon success */
+               newifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
+               if (newifa != NULL) {
+                       ifafree(ifa);
+                       ifa = newifa;
+               }
+       }
+       /*
+        * If we are adding a gateway, it is quite possible that the
+        * routing table has a static entry in place for the gateway,
+        * that may not agree with info garnered from the interfaces.
+        * The routing table should carry more precedence than the
+        * interfaces in this matter.  Must be careful not to stomp
+        * on new entries from rtinit, hence (ifa->ifa_addr != gateway).
+        */
+       if ((ifa == NULL ||
+           !equal(ifa->ifa_addr, (struct sockaddr *)(size_t)gateway)) &&
+           (rt = rtalloc1_scoped_locked((struct sockaddr *)(size_t)gateway,
+           0, 0UL, ifscope)) != NULL) {
+               if (ifa != NULL)
+                       ifafree(ifa);
+               ifa = rt->rt_ifa;
+               if (ifa != NULL)
+                       ifaref(ifa);
                rtunref(rt);
-               if ((ifa = rt->rt_ifa) == 0)
-                       return (0);
        }
-       if (ifa->ifa_addr->sa_family != dst->sa_family) {
-               struct ifaddr *oifa = ifa;
-               ifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
-               if (ifa == 0)
-                       ifa = oifa;
+       /*
+        * If an interface scope was specified, the interface index of
+        * the found ifaddr must be equivalent to that of the scope;
+        * otherwise there is no match.
+        */
+       if ((flags & RTF_IFSCOPE) &&
+           ifa != NULL && ifa->ifa_ifp->if_index != ifscope) {
+               ifafree(ifa);
+               ifa = NULL;
        }
+
        return (ifa);
 }
 
@@ -562,24 +1081,58 @@ struct rtfc_arg {
        struct radix_node_head *rnh;
 };
 
+int
+rtrequest_locked(int req, struct sockaddr *dst, struct sockaddr *gateway,
+    struct sockaddr *netmask, int flags, struct rtentry **ret_nrt)
+{
+       return (rtrequest_common_locked(req, dst, gateway, netmask,
+           (flags & ~RTF_IFSCOPE), ret_nrt, IFSCOPE_NONE));
+}
+
+int
+rtrequest_scoped_locked(int req, struct sockaddr *dst,
+    struct sockaddr *gateway, struct sockaddr *netmask, int flags,
+    struct rtentry **ret_nrt, unsigned int ifscope)
+{
+       if (ifscope != IFSCOPE_NONE)
+               flags |= RTF_IFSCOPE;
+       else
+               flags &= ~RTF_IFSCOPE;
+
+       return (rtrequest_common_locked(req, dst, gateway, netmask,
+           flags, ret_nrt, ifscope));
+}
+
 /*
- * Do appropriate manipulations of a routing tree given
- * all the bits of info needed
+ * Do appropriate manipulations of a routing tree given all the bits of
+ * info needed.
+ *
+ * Embedding the scope in the radix key is an internal job that should be
+ * left to routines in this module.  Callers should specify the scope value
+ * to the "scoped" variants of route routines instead of manipulating the
+ * key itself.  This is typically done when creating a scoped route, e.g.
+ * rtrequest(RTM_ADD).  Once such a route is created and marked with the
+ * RTF_IFSCOPE flag, callers can simply use its rt_key(rt) to clone it
+ * (RTM_RESOLVE) or to remove it (RTM_DELETE).  An exception to this is
+ * during certain routing socket operations where the search key might be
+ * derived from the routing message itself, in which case the caller must
+ * specify the destination address and scope value for RTM_ADD/RTM_DELETE.
  */
-int
-rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
-       int req, flags;
-       struct sockaddr *dst, *gateway, *netmask;
-       struct rtentry **ret_nrt;
+static int
+rtrequest_common_locked(int req, struct sockaddr *dst0,
+    struct sockaddr *gateway, struct sockaddr *netmask, int flags,
+    struct rtentry **ret_nrt, unsigned int ifscope)
 {
-       int s = splnet(); int error = 0;
-       register struct rtentry *rt;
-       register struct radix_node *rn;
-       register struct radix_node_head *rnh;
-       struct ifaddr *ifa;
-       struct sockaddr *ndst;
+       int error = 0;
+       struct rtentry *rt;
+       struct radix_node *rn;
+       struct radix_node_head *rnh;
+       struct ifaddr *ifa = NULL;
+       struct sockaddr *ndst, *dst = dst0;
+       struct sockaddr_in sin, mask;
 #define senderr(x) { error = x ; goto bad; }
 
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
        /*
         * Find the correct routing tree to use for this Address Family
         */
@@ -591,6 +1144,37 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
         */
        if (flags & RTF_HOST)
                netmask = 0;
+
+       /*
+        * If RTF_IFSCOPE is specified, use a local copy of the destination
+        * address to embed the scope into.  This logic is repeated below
+        * in the RTM_RESOLVE handler since the caller does not normally
+        * specify such a flag during a resolve; instead it passes in the
+        * route used for cloning for which the scope info is derived from.
+        * Note also that in the case of RTM_DELETE, the address passed in
+        * by the caller might already contain the embedded scope info when
+        * it is the key itself, thus making RTF_IFSCOPE unnecessary; one
+        * instance where it is explicitly set is inside route_output()
+        * as part of handling a routing socket request.
+        */
+       if (req != RTM_RESOLVE && (flags & RTF_IFSCOPE)) {
+               /* Scoped routing is for AF_INET only */
+               if (dst->sa_family != AF_INET ||
+                   (req == RTM_ADD && !ip_doscopedroute))
+                       senderr(EINVAL);
+
+               if (ifscope == IFSCOPE_NONE) {
+                       flags &= ~RTF_IFSCOPE;
+               } else {
+                       /* Embed ifscope into the key (local copy) */
+                       dst = sin_copy(SIN(dst), &sin, ifscope);
+
+                       /* Embed ifscope into netmask (local copy) */
+                       if (netmask != NULL)
+                               netmask = mask_copy(netmask, &mask, ifscope);
+               }
+       }
+
        switch (req) {
        case RTM_DELETE:
                /*
@@ -603,6 +1187,18 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                        panic ("rtrequest delete");
                rt = (struct rtentry *)rn;
 
+               /*
+                * Take an extra reference to handle the deletion of a route
+                * entry whose reference count is already 0; e.g. an expiring
+                * cloned route entry or an entry that was added to the table
+                * with 0 reference. If the caller is interested in this route,
+                * we will return it with the reference intact. Otherwise we
+                * will decrement the reference via rtfree_locked() and then
+                * possibly deallocate it.
+                */
+               rtref(rt);
+               rt->rt_flags &= ~RTF_UP;
+
                /*
                 * Now search what's left of the subtree for any cloned
                 * routes which might have been formed from this node.
@@ -620,41 +1216,45 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                 */
                if (rt->rt_gwroute) {
                        rt = rt->rt_gwroute;
-                       rtfree(rt);
+                       rtfree_locked(rt);
                        (rt = (struct rtentry *)rn)->rt_gwroute = 0;
                }
 
-               /*
-                * NB: RTF_UP must be set during the search above,
-                * because we might delete the last ref, causing
-                * rt to get freed prematurely.
-                *  eh? then why not just add a reference?
-                * I'm not sure how RTF_UP helps matters. (JRE)
-                */
-               rt->rt_flags &= ~RTF_UP;
-
                /*
                 * give the protocol a chance to keep things in sync.
                 */
                if ((ifa = rt->rt_ifa) && ifa->ifa_rtrequest)
                        ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
+               ifa = NULL;
 
                /*
                 * one more rtentry floating around that is not
                 * linked to the routing table.
                 */
-               rttrash++;
+               (void) OSIncrementAtomic((SInt32 *)&rttrash);
+               if (rte_debug & RTD_DEBUG) {
+                       TAILQ_INSERT_TAIL(&rttrash_head,
+                           (struct rtentry_dbg *)rt, rtd_trash_link);
+               }
+
+               /*
+                * If this is the (non-scoped) default route, clear
+                * the interface index used for the primary ifscope.
+                */
+               if (rt_inet_default(rt, rt_key(rt)))
+                       set_primary_ifscope(IFSCOPE_NONE);
 
                /*
                 * If the caller wants it, then it can have it,
                 * but it's up to it to free the rtentry as we won't be
                 * doing it.
                 */
-               if (ret_nrt)
+               if (ret_nrt != NULL) {
+                       /* Return the route to caller with reference intact */
                        *ret_nrt = rt;
-               else if (rt->rt_refcnt <= 0) {
-                       rt->rt_refcnt++; /* make a 1->0 transition */
-                       rtfree(rt);
+               } else {
+                       /* Dereference or deallocate the route */
+                       rtfree_locked(rt);
                }
                break;
 
@@ -662,33 +1262,67 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                if (ret_nrt == 0 || (rt = *ret_nrt) == 0)
                        senderr(EINVAL);
                ifa = rt->rt_ifa;
+               ifaref(ifa);
                flags = rt->rt_flags &
                    ~(RTF_CLONING | RTF_PRCLONING | RTF_STATIC);
                flags |= RTF_WASCLONED;
                gateway = rt->rt_gateway;
                if ((netmask = rt->rt_genmask) == 0)
                        flags |= RTF_HOST;
+
+               if (!ip_doscopedroute || dst->sa_family != AF_INET)
+                       goto makeroute;
+               /*
+                * When scoped routing is enabled, cloned entries are
+                * always scoped according to the interface portion of
+                * the parent route.  The exception to this are IPv4
+                * link local addresses.
+                */
+               if (!IN_LINKLOCAL(ntohl(SIN(dst)->sin_addr.s_addr))) {
+                       if (flags & RTF_IFSCOPE) {
+                               ifscope = sa_get_ifscope(rt_key(rt));
+                       } else {
+                               ifscope = rt->rt_ifp->if_index;
+                               flags |= RTF_IFSCOPE;
+                       }
+               } else {
+                       ifscope = IFSCOPE_NONE;
+                       flags &= ~RTF_IFSCOPE;
+               }
+
+               /* Embed or clear ifscope into/from the key (local copy) */
+               dst = sin_copy(SIN(dst), &sin, ifscope);
+
+               /* Embed or clear ifscope into/from netmask (local copy) */
+               if (netmask != NULL)
+                       netmask = mask_copy(netmask, &mask, ifscope);
+
                goto makeroute;
 
        case RTM_ADD:
                if ((flags & RTF_GATEWAY) && !gateway)
-                       panic("rtrequest: GATEWAY but no gateway");
+                       panic("rtrequest: RTF_GATEWAY but no gateway");
 
-               if ((ifa = ifa_ifwithroute(flags, dst, gateway)) == 0)
+               if (flags & RTF_IFSCOPE) {
+                       ifa = ifa_ifwithroute_scoped_locked(flags, dst0,
+                           gateway, ifscope);
+               } else {
+                       ifa = ifa_ifwithroute_locked(flags, dst0, gateway);
+               }
+               if (ifa == NULL)
                        senderr(ENETUNREACH);
-
-       makeroute:
-               R_Malloc(rt, struct rtentry *, sizeof(*rt));
-               if (rt == 0)
+makeroute:
+               if ((rt = rte_alloc()) == NULL)
                        senderr(ENOBUFS);
                Bzero(rt, sizeof(*rt));
                rt->rt_flags = RTF_UP | flags;
+
                /*
                 * Add the gateway. Possibly re-malloc-ing the storage for it
                 * also add the rt_gwroute if possible.
                 */
                if ((error = rt_setgate(rt, dst, gateway)) != 0) {
-                       Free(rt);
+                       rte_free(rt);
                        senderr(error);
                }
 
@@ -700,9 +1334,9 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                /*
                 * make sure it contains the value we want (masked if needed).
                 */
-               if (netmask) {
+               if (netmask)
                        rt_maskedcopy(dst, ndst, netmask);
-               else
+               else
                        Bcopy(dst, ndst, dst->sa_len);
 
                /*
@@ -710,16 +1344,9 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                 * This moved from below so that rnh->rnh_addaddr() can
                 * examine the ifa and  ifa->ifa_ifp if it so desires.
                 */
-               /*
-                * Note that we do not use rtsetifa here because
-                * rt_parent has not been setup yet.
-                */
-               ifaref(ifa);
-               rt->rt_ifa = ifa;
-               rt->rt_ifp = ifa->ifa_ifp;
-#ifdef __APPLE__
-               rt->rt_dlt = ifa->ifa_dlt; /* dl_tag */
-#endif
+               rtsetifa(rt, ifa);
+               rt->rt_ifp = rt->rt_ifa->ifa_ifp;
+
                /* XXX mtu manipulation will be done in rnh_addaddr -- itojun */
 
                rn = rnh->rnh_addaddr((caddr_t)ndst, (caddr_t)netmask,
@@ -733,19 +1360,25 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                         * mechanism, then we just blow it away and retry
                         * the insertion of the new one.
                         */
-                       rt2 = rtalloc1(dst, 0, RTF_PRCLONING);
+                       if (flags & RTF_IFSCOPE) {
+                               rt2 = rtalloc1_scoped_locked(dst0, 0,
+                                   RTF_CLONING | RTF_PRCLONING, ifscope);
+                       } else {
+                               rt2 = rtalloc1_locked(dst, 0,
+                                   RTF_CLONING | RTF_PRCLONING);
+                       }
                        if (rt2 && rt2->rt_parent) {
-                               rtrequest(RTM_DELETE,
+                               rtrequest_locked(RTM_DELETE,
                                          (struct sockaddr *)rt_key(rt2),
                                          rt2->rt_gateway,
                                          rt_mask(rt2), rt2->rt_flags, 0);
-                               rtfree(rt2);
+                               rtfree_locked(rt2);
                                rn = rnh->rnh_addaddr((caddr_t)ndst,
                                                      (caddr_t)netmask,
                                                      rnh, rt->rt_nodes);
                        } else if (rt2) {
                                /* undo the extra ref we got */
-                               rtfree(rt2);
+                               rtfree_locked(rt2);
                        }
                }
 
@@ -755,12 +1388,12 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                 */
                if (rn == 0) {
                        if (rt->rt_gwroute)
-                               rtfree(rt->rt_gwroute);
+                               rtfree_locked(rt->rt_gwroute);
                        if (rt->rt_ifa) {
                                ifafree(rt->rt_ifa);
                        }
-                       Free(rt_key(rt));
-                       Free(rt);
+                       R_Free(rt_key(rt));
+                       rte_free(rt);
                        senderr(EEXIST);
                }
 
@@ -776,13 +1409,6 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                        if ((*ret_nrt)->rt_flags & (RTF_CLONING | RTF_PRCLONING)) {
                                rt->rt_parent = (*ret_nrt);
                                rtref(*ret_nrt);
-
-                               /*
-                                * If our parent is holding a reference to the same ifa,
-                                * free our reference and rely on the parent holding it.
-                                */
-                               if (rt->rt_parent && rt->rt_parent->rt_ifa == rt->rt_ifa)
-                                       ifafree(rt->rt_ifa);
                        }
                }
 
@@ -792,6 +1418,8 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                 */
                if (ifa->ifa_rtrequest)
                        ifa->ifa_rtrequest(req, rt, SA(ret_nrt ? *ret_nrt : 0));
+               ifafree(ifa);
+               ifa = 0;
 
                /*
                 * We repeat the same procedure from rt_setgate() here because
@@ -806,6 +1434,13 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                                               rt_fixchange, &arg);
                }
 
+               /*
+                * If this is the (non-scoped) default route, record
+                * the interface index used for the primary ifscope.
+                */
+               if (rt_inet_default(rt, rt_key(rt)))
+                       set_primary_ifscope(rt->rt_ifp->if_index);
+
                /*
                 * actually return a resultant rtentry and
                 * give the caller a single reference.
@@ -817,10 +1452,27 @@ rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
                break;
        }
 bad:
-       splx(s);
+       if (ifa)
+               ifafree(ifa);
        return (error);
 }
 
+int
+rtrequest(
+       int req,
+       struct sockaddr *dst,
+       struct sockaddr *gateway,
+       struct sockaddr *netmask,
+       int flags,
+       struct rtentry **ret_nrt)
+{
+       int error;
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);
+       error = rtrequest_locked(req, dst, gateway, netmask, flags, ret_nrt);
+       lck_mtx_unlock(rt_mtx);
+       return (error);
+}
 /*
  * Called from rtrequest(RTM_DELETE, ...) to fix up the route's ``family''
  * (i.e., the routes related to it by the operation of cloning).  This
@@ -829,15 +1481,16 @@ bad:
  * the late parent (passed in as VP here) are themselves deleted.
  */
 static int
-rt_fixdelete(rn, vp)
-       struct radix_node *rn;
-       void *vp;
+rt_fixdelete(struct radix_node *rn, void *vp)
 {
        struct rtentry *rt = (struct rtentry *)rn;
        struct rtentry *rt0 = vp;
 
-       if (rt->rt_parent == rt0 && !(rt->rt_flags & RTF_PINNED)) {
-               return rtrequest(RTM_DELETE, rt_key(rt),
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       if (rt->rt_parent == rt0 &&
+           !(rt->rt_flags & (RTF_PINNED | RTF_CLONING | RTF_PRCLONING))) {
+               return rtrequest_locked(RTM_DELETE, rt_key(rt),
                                 (struct sockaddr *)0, rt_mask(rt),
                                 rt->rt_flags, (struct rtentry **)0);
        }
@@ -857,14 +1510,8 @@ rt_fixdelete(rn, vp)
  * routine just for adds.  I'm not sure why I thought it was necessary to do
  * changes this way.
  */
-#ifdef DEBUG
-static int rtfcdebug = 0;
-#endif
-
 static int
-rt_fixchange(rn, vp)
-       struct radix_node *rn;
-       void *vp;
+rt_fixchange(struct radix_node *rn, void *vp)
 {
        struct rtentry *rt = (struct rtentry *)rn;
        struct rtfc_arg *ap = vp;
@@ -873,33 +1520,20 @@ rt_fixchange(rn, vp)
        u_char *xk1, *xm1, *xk2, *xmp;
        int i, len, mlen;
 
-#ifdef DEBUG
-       if (rtfcdebug)
-               printf("rt_fixchange: rt %p, rt0 %p\n", rt, rt0);
-#endif
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
 
-       if (!rt->rt_parent || (rt->rt_flags & RTF_PINNED)) {
-#ifdef DEBUG
-               if(rtfcdebug) printf("no parent or pinned\n");
-#endif
-               return 0;
-       }
+       if (!rt->rt_parent ||
+           (rt->rt_flags & (RTF_PINNED | RTF_CLONING | RTF_PRCLONING)))
+               return (0);
 
-       if (rt->rt_parent == rt0) {
-#ifdef DEBUG
-               if(rtfcdebug) printf("parent match\n");
-#endif
-               return rtrequest(RTM_DELETE, rt_key(rt),
-                                (struct sockaddr *)0, rt_mask(rt),
-                                rt->rt_flags, (struct rtentry **)0);
-       }
+       if (rt->rt_parent == rt0)
+               goto delete_rt;
 
        /*
         * There probably is a function somewhere which does this...
         * if not, there should be.
         */
-       len = imin(((struct sockaddr *)rt_key(rt0))->sa_len,
-                  ((struct sockaddr *)rt_key(rt))->sa_len);
+       len = imin(rt_key(rt0)->sa_len, rt_key(rt)->sa_len);
 
        xk1 = (u_char *)rt_key(rt0);
        xm1 = (u_char *)rt_mask(rt0);
@@ -907,134 +1541,168 @@ rt_fixchange(rn, vp)
 
        /* avoid applying a less specific route */
        xmp = (u_char *)rt_mask(rt->rt_parent);
-       mlen = ((struct sockaddr *)rt_key(rt->rt_parent))->sa_len;
-       if (mlen > ((struct sockaddr *)rt_key(rt0))->sa_len) {
-#if DEBUG
-               if (rtfcdebug)
-                       printf("rt_fixchange: inserting a less "
-                              "specific route\n");
-#endif
-               return 0;
-       }
+       mlen = rt_key(rt->rt_parent)->sa_len;
+       if (mlen > rt_key(rt0)->sa_len)
+               return (0);
+
        for (i = rnh->rnh_treetop->rn_offset; i < mlen; i++) {
-               if ((xmp[i] & ~(xmp[i] ^ xm1[i])) != xmp[i]) {
-#if DEBUG
-                       if (rtfcdebug)
-                               printf("rt_fixchange: inserting a less "
-                                      "specific route\n");
-#endif
-                       return 0;
-               }
+               if ((xmp[i] & ~(xmp[i] ^ xm1[i])) != xmp[i])
+                       return (0);
        }
 
        for (i = rnh->rnh_treetop->rn_offset; i < len; i++) {
-               if ((xk2[i] & xm1[i]) != xk1[i]) {
-#ifdef DEBUG
-                       if(rtfcdebug) printf("no match\n");
-#endif
-                       return 0;
-               }
+               if ((xk2[i] & xm1[i]) != xk1[i])
+                       return (0);
        }
 
        /*
         * OK, this node is a clone, and matches the node currently being
         * changed/added under the node's mask.  So, get rid of it.
         */
-#ifdef DEBUG
-       if(rtfcdebug) printf("deleting\n");
-#endif
-       return rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0,
-                        rt_mask(rt), rt->rt_flags, (struct rtentry **)0);
+delete_rt:
+       return (rtrequest_locked(RTM_DELETE, rt_key(rt), NULL,
+           rt_mask(rt), rt->rt_flags, NULL));
 }
 
 int
-rt_setgate(rt0, dst, gate)
-       struct rtentry *rt0;
-       struct sockaddr *dst, *gate;
+rt_setgate(struct rtentry *rt, struct sockaddr *dst, struct sockaddr *gate)
 {
-       caddr_t new, old;
        int dlen = ROUNDUP(dst->sa_len), glen = ROUNDUP(gate->sa_len);
-       register struct rtentry *rt = rt0;
        struct radix_node_head *rnh = rt_tables[dst->sa_family];
 
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
        /*
         * A host route with the destination equal to the gateway
         * will interfere with keeping LLINFO in the routing
         * table, so disallow it.
         */
-       if (((rt0->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_LLINFO)) ==
-                                       (RTF_HOST|RTF_GATEWAY)) &&
-           (dst->sa_len == gate->sa_len) &&
+       if (((rt->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_LLINFO)) ==
+           (RTF_HOST|RTF_GATEWAY)) && (dst->sa_len == gate->sa_len) &&
            (bcmp(dst, gate, dst->sa_len) == 0)) {
                /*
                 * The route might already exist if this is an RTM_CHANGE
                 * or a routing redirect, so try to delete it.
                 */
-               if (rt_key(rt0))
-                       rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt0),
-                           rt0->rt_gateway, rt_mask(rt0), rt0->rt_flags, 0);
-               return EADDRNOTAVAIL;
+               if (rt_key(rt))
+                       rtrequest_locked(RTM_DELETE, rt_key(rt),
+                           rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL);
+               return (EADDRNOTAVAIL);
        }
 
        /*
-        * Both dst and gateway are stored in the same malloc'd chunk
-        * (If I ever get my hands on....)
-        * if we need to malloc a new chunk, then keep the old one around
-        * till we don't need it any more.
+        * The destination is not directly reachable.  Get a route
+        * to the next-hop gateway and store it in rt_gwroute.
         */
-       if (rt->rt_gateway == 0 || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
-               old = (caddr_t)rt_key(rt);
-               R_Malloc(new, caddr_t, dlen + glen);
-               if (new == 0)
-                       return ENOBUFS;
-               rt->rt_nodes->rn_key = new;
-       } else {
+       if (rt->rt_flags & RTF_GATEWAY) {
+               struct rtentry *gwrt;
+               unsigned int ifscope;
+
+               ifscope = (dst->sa_family == AF_INET) ?
+                   sa_get_ifscope(dst) : IFSCOPE_NONE;
+
+               gwrt = rtalloc1_scoped_locked(gate, 1, RTF_PRCLONING, ifscope);
+
+               /*
+                * Cloning loop avoidance:
+                *
+                * In the presence of protocol-cloning and bad configuration,
+                * it is possible to get stuck in bottomless mutual recursion
+                * (rtrequest rt_setgate rtalloc1).  We avoid this by not
+                * allowing protocol-cloning to operate for gateways (which
+                * is probably the correct choice anyway), and avoid the
+                * resulting reference loops by disallowing any route to run
+                * through itself as a gateway.  This is obviously mandatory
+                * when we get rt->rt_output().  It implies that a route to
+                * the gateway must already be present in the system in order
+                * for the gateway to be referred to by another route.
+                */
+               if (gwrt == rt) {
+                       rtunref(gwrt);
+                       return (EADDRINUSE); /* failure */
+               }
+
+               /* If scoped, the gateway route must use the same interface */
+               if (ifscope != IFSCOPE_NONE && (rt->rt_flags & RTF_IFSCOPE) &&
+                   gwrt != NULL && gwrt->rt_ifp != NULL &&
+                   gwrt->rt_ifp->if_index != ifscope) {
+                       rtfree_locked(gwrt);
+                       return ((rt->rt_flags & RTF_HOST) ?
+                           EHOSTUNREACH : ENETUNREACH);
+               }
+
+               if (rt->rt_gwroute != NULL)
+                       rtfree_locked(rt->rt_gwroute);
+               rt->rt_gwroute = gwrt;
+
                /*
-                * otherwise just overwrite the old one
+                * In case the (non-scoped) default route gets modified via
+                * an ICMP redirect, record the interface index used for the
+                * primary ifscope.  Also done in rt_setif() to take care
+                * of the non-redirect cases.
                 */
-               new = rt->rt_nodes->rn_key;
-               old = 0;
+               if (rt_inet_default(rt, dst) && rt->rt_ifp != NULL)
+                       set_primary_ifscope(rt->rt_ifp->if_index);
+
+               /*
+                * Tell the kernel debugger about the new default gateway
+                * if the gateway route uses the primary interface, or
+                * if we are in a transient state before the non-scoped
+                * default gateway is installed (similar to how the system
+                * was behaving in the past).  In future, it would be good
+                * to do all this only when KDP is enabled.
+                */
+               if ((dst->sa_family == AF_INET) &&
+                   gwrt != NULL && gwrt->rt_gateway->sa_family == AF_LINK &&
+                   (gwrt->rt_ifp->if_index == get_primary_ifscope() ||
+                   get_primary_ifscope() == IFSCOPE_NONE))
+                       kdp_set_gateway_mac(SDL(gwrt->rt_gateway)->sdl_data);
        }
 
        /*
-        * copy the new gateway value into the memory chunk
+        * Prepare to store the gateway in rt_gateway.  Both dst and gateway
+        * are stored one after the other in the same malloc'd chunk.  If we
+        * have room, reuse the old buffer since rt_gateway already points
+        * to the right place.  Otherwise, malloc a new block and update
+        * the 'dst' address and point rt_gateway to the right place.
         */
-       Bcopy(gate, (rt->rt_gateway = (struct sockaddr *)(new + dlen)), glen);
+       if (rt->rt_gateway == NULL || glen > ROUNDUP(rt->rt_gateway->sa_len)) {
+               caddr_t new;
 
-       /*
-        * if we are replacing the chunk (or it's new) we need to
-        * replace the dst as well
-        */
-       if (old) {
+               /* The underlying allocation is done with M_WAITOK set */
+               R_Malloc(new, caddr_t, dlen + glen);
+               if (new == NULL) {
+                       if (rt->rt_gwroute != NULL)
+                               rtfree_locked(rt->rt_gwroute);
+                       rt->rt_gwroute = NULL;
+                       return (ENOBUFS);
+               }
+
+               /*
+                * Copy from 'dst' and not rt_key(rt) because we can get
+                * here to initialize a newly allocated route entry, in
+                * which case rt_key(rt) is NULL (and so does rt_gateway).
+                */
                Bcopy(dst, new, dlen);
-               Free(old);
+               R_Free(rt_key(rt));     /* free old block; NULL is okay */
+               rt->rt_nodes->rn_key = new;
+               rt->rt_gateway = (struct sockaddr *)(new + dlen);
        }
 
        /*
-        * If there is already a gwroute, it's now almost definitly wrong
-        * so drop it.
+        * Copy the new gateway value into the memory chunk.
         */
-       if (rt->rt_gwroute) {
-               rt = rt->rt_gwroute; rtfree(rt);
-               rt = rt0; rt->rt_gwroute = 0;
-       }
+       Bcopy(gate, rt->rt_gateway, glen);
+
        /*
-        * Cloning loop avoidance:
-        * In the presence of protocol-cloning and bad configuration,
-        * it is possible to get stuck in bottomless mutual recursion
-        * (rtrequest rt_setgate rtalloc1).  We avoid this by not allowing
-        * protocol-cloning to operate for gateways (which is probably the
-        * correct choice anyway), and avoid the resulting reference loops
-        * by disallowing any route to run through itself as a gateway.
-        * This is obviously mandatory when we get rt->rt_output().
+        * For consistency between rt_gateway and rt_key(gwrt).
         */
-       if (rt->rt_flags & RTF_GATEWAY) {
-               rt->rt_gwroute = rtalloc1(gate, 1, RTF_PRCLONING);
-               if (rt->rt_gwroute == rt) {
-                       rtfree(rt->rt_gwroute);
-                       rt->rt_gwroute = 0;
-                       return EDQUOT; /* failure */
-               }
+       if ((rt->rt_flags & RTF_GATEWAY) && rt->rt_gwroute != NULL &&
+           (rt->rt_gwroute->rt_flags & RTF_IFSCOPE) &&
+           rt->rt_gateway->sa_family == AF_INET &&
+           rt_key(rt->rt_gwroute)->sa_family == AF_INET) {
+               sa_set_ifscope(rt->rt_gateway,
+                   sa_get_ifscope(rt_key(rt->rt_gwroute)));
        }
 
        /*
@@ -1047,19 +1715,19 @@ rt_setgate(rt0, dst, gate)
                arg.rnh = rnh;
                arg.rt0 = rt;
                rnh->rnh_walktree_from(rnh, rt_key(rt), rt_mask(rt),
-                                      rt_fixchange, &arg);
+                   rt_fixchange, &arg);
        }
 
-       return 0;
+       return (0);
 }
 
 static void
-rt_maskedcopy(src, dst, netmask)
-       struct sockaddr *src, *dst, *netmask;
+rt_maskedcopy(struct sockaddr *src, struct sockaddr *dst,
+             struct sockaddr *netmask)
 {
-       register u_char *cp1 = (u_char *)src;
-       register u_char *cp2 = (u_char *)dst;
-       register u_char *cp3 = (u_char *)netmask;
+       u_char *cp1 = (u_char *)src;
+       u_char *cp2 = (u_char *)dst;
+       u_char *cp3 = (u_char *)netmask;
        u_char *cplim = cp2 + *cp3;
        u_char *cplim2 = cp2 + *cp1;
 
@@ -1073,18 +1741,223 @@ rt_maskedcopy(src, dst, netmask)
                bzero((caddr_t)cp2, (unsigned)(cplim2 - cp2));
 }
 
+/*
+ * Lookup an AF_INET scoped or non-scoped route depending on the ifscope
+ * value passed in by the caller (IFSCOPE_NONE implies non-scoped).
+ */
+static struct radix_node *
+node_lookup(struct sockaddr *dst, struct sockaddr *netmask,
+    unsigned int ifscope)
+{
+       struct radix_node_head *rnh = rt_tables[AF_INET];
+       struct radix_node *rn;
+       struct sockaddr_in sin, mask;
+       struct matchleaf_arg ma = { ifscope };
+       rn_matchf_t *f = rn_match_ifscope;
+       void *w = &ma;
+
+       if (dst->sa_family != AF_INET)
+               return (NULL);
+
+       /*
+        * Embed ifscope into the search key; for a non-scoped
+        * search this will clear out any embedded scope value.
+        */
+       dst = sin_copy(SIN(dst), &sin, ifscope);
+
+       /* Embed (or clear) ifscope into netmask */
+       if (netmask != NULL)
+               netmask = mask_copy(netmask, &mask, ifscope);
+
+       if (ifscope == IFSCOPE_NONE)
+               f = w = NULL;
+
+       rn = rnh->rnh_lookup_args(dst, netmask, rnh, f, w);
+       if (rn != NULL && (rn->rn_flags & RNF_ROOT))
+               rn = NULL;
+
+       return (rn);
+}
+
+/*
+ * Lookup the AF_INET non-scoped default route.
+ */
+static struct radix_node *
+node_lookup_default(void)
+{
+       struct radix_node_head *rnh = rt_tables[AF_INET];
+       return (rnh->rnh_lookup(&sin_def, NULL, rnh));
+}
+
+/*
+ * Common routine to lookup/match a route.  It invokes the lookup/matchaddr
+ * callback which could be address family-specific.  The main difference
+ * between the two (at least for AF_INET/AF_INET6) is that a lookup does
+ * not alter the expiring state of a route, whereas a match would unexpire
+ * or revalidate the route.
+ *
+ * The optional scope or interface index property of a route allows for a
+ * per-interface route instance.  This permits multiple route entries having
+ * the same destination (but not necessarily the same gateway) to exist in
+ * the routing table; each of these entries is specific to the corresponding
+ * interface.  This is made possible by embedding the scope value into the
+ * radix key, thus making each route entry unique.  These scoped entries
+ * exist along with the regular, non-scoped entries in the same radix tree
+ * for a given address family (currently AF_INET only); the scope logically
+ * partitions it into multiple per-interface sub-trees.
+ *
+ * When a scoped route lookup is performed, the routing table is searched for
+ * the best match that would result in a route using the same interface as the
+ * one associated with the scope (the exception to this are routes that point
+ * to the loopback interface).  The search rule follows the longest matching
+ * prefix with the additional interface constraint.
+ */
+struct rtentry *
+rt_lookup(boolean_t lookup_only, struct sockaddr *dst, struct sockaddr *netmask,
+    struct radix_node_head *rnh, unsigned int ifscope)
+{
+       struct radix_node *rn0, *rn;
+       boolean_t dontcare = (ifscope == IFSCOPE_NONE);
+
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_OWNED);
+
+       if (!lookup_only)
+               netmask = NULL;
+
+       /*
+        * Non-scoped route lookup.
+        */
+       if (!ip_doscopedroute || dst->sa_family != AF_INET) {
+               if (lookup_only)
+                       rn = rnh->rnh_lookup(dst, netmask, rnh);
+               else
+                       rn = rnh->rnh_matchaddr(dst, rnh);
+               goto done;
+       }
+
+       /*
+        * Scoped route lookup:
+        *
+        * We first perform a non-scoped lookup for the original result.
+        * Afterwards, depending on whether or not the caller has specified
+        * a scope, we perform a more specific scoped search and fallback
+        * to this original result upon failure.
+        */
+       rn0 = rn = node_lookup(dst, netmask, IFSCOPE_NONE);
+
+       /*
+        * If the caller did not specify a scope, use the primary scope
+        * derived from the system's non-scoped default route.  If, for
+        * any reason, there is no primary interface, return what we have.
+        */
+       if (dontcare && (ifscope = get_primary_ifscope()) == IFSCOPE_NONE)
+               goto validate;
+
+       /*
+        * Keep the original result if either of the following is true:
+        *
+        *   1) The interface portion of the route has the same interface
+        *      index as the scope value and it is marked with RTF_IFSCOPE.
+        *   2) The route uses the loopback interface, in which case the
+        *      destination (host/net) is local/loopback.
+        *
+        * Otherwise, do a more specified search using the scope.
+        */
+       if (rn != NULL) {
+               struct rtentry *rt = RT(rn);
+               if (rt->rt_ifp != lo_ifp) {
+                       if (rt->rt_ifp->if_index != ifscope) {
+                               /*
+                                * Wrong interface; keep the original result
+                                * only if the caller did not specify a scope,
+                                * and do a more specific scoped search using
+                                * the scope of the found route.  Otherwise,
+                                * start again from scratch.
+                                */
+                               rn = NULL;
+                               if (dontcare)
+                                       ifscope = rt->rt_ifp->if_index;
+                               else
+                                       rn0 = NULL;
+                       } else if (!(rt->rt_flags & RTF_IFSCOPE)) {
+                               /*
+                                * Right interface, except that this route
+                                * isn't marked with RTF_IFSCOPE.  Do a more
+                                * specific scoped search.  Keep the original
+                                * result and return it it in case the scoped
+                                * search fails.
+                                */
+                               rn = NULL;
+                       }
+               }
+       }
+
+       /*
+        * Scoped search.  Find the most specific entry having the same
+        * interface scope as the one requested.  The following will result
+        * in searching for the longest prefix scoped match.
+        */
+       if (rn == NULL)
+               rn = node_lookup(dst, netmask, ifscope);
+
+       /*
+        * Use the original result if either of the following is true:
+        *
+        *   1) The scoped search did not yield any result.
+        *   2) The result from the scoped search is a scoped default route,
+        *      and the original (non-scoped) result is not a default route,
+        *      i.e. the original result is a more specific host/net route.
+        *   3) The scoped search yielded a net route but the original
+        *      result is a host route, i.e. the original result is treated
+        *      as a more specific route.
+        */
+       if (rn == NULL || (rn0 != NULL &&
+           ((INET_DEFAULT(rt_key(RT(rn))) && !INET_DEFAULT(rt_key(RT(rn0)))) ||
+           (!RT_HOST(rn) && RT_HOST(rn0)))))
+               rn = rn0;
+
+       /*
+        * If we still don't have a route, use the non-scoped default
+        * route as long as the interface portion satistifes the scope.
+        */
+       if (rn == NULL && (rn = node_lookup_default()) != NULL &&
+           RT(rn)->rt_ifp->if_index != ifscope)
+               rn = NULL;
+
+validate:
+       if (rn != NULL && !lookup_only)
+               (void) in_validate(rn);
+
+done:
+       if (rn != NULL && (rn->rn_flags & RNF_ROOT))
+               rn = NULL;
+       else if (rn != NULL)
+               rtref(RT(rn));
+
+       return (RT(rn));
+}
+
 /*
  * Set up a routing table entry, normally
  * for an interface.
  */
 int
-rtinit(ifa, cmd, flags)
-       register struct ifaddr *ifa;
-       int cmd, flags;
+rtinit(struct ifaddr *ifa, int cmd, int flags)
+{
+       int error;
+       lck_mtx_assert(rt_mtx, LCK_MTX_ASSERT_NOTOWNED);
+       lck_mtx_lock(rt_mtx);
+       error = rtinit_locked(ifa, cmd, flags);
+       lck_mtx_unlock(rt_mtx);
+       return (error);
+}
+
+int
+rtinit_locked(struct ifaddr *ifa, int cmd, int flags)
 {
-       register struct rtentry *rt;
-       register struct sockaddr *dst;
-       register struct sockaddr *deldst;
+       struct rtentry *rt;
+       struct sockaddr *dst;
+       struct sockaddr *deldst;
        struct mbuf *m = 0;
        struct rtentry *nrt = 0;
        int error;
@@ -1103,8 +1976,9 @@ rtinit(ifa, cmd, flags)
                 */
                if ((flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
                        m = m_get(M_DONTWAIT, MT_SONAME);
-                       if (m == NULL)
+                       if (m == NULL) {
                                return(ENOBUFS);
+                       }
                        deldst = mtod(m, struct sockaddr *);
                        rt_maskedcopy(dst, deldst, ifa->ifa_netmask);
                        dst = deldst;
@@ -1115,7 +1989,7 @@ rtinit(ifa, cmd, flags)
                 * We set "report" to FALSE so that if it doesn't exist,
                 * it doesn't report an error or clone a route, etc. etc.
                 */
-               rt = rtalloc1(dst, 0, 0UL);
+               rt = rtalloc1_locked(dst, 0, 0UL);
                if (rt) {
                        /*
                         * Ok so we found the rtentry. it has an extra reference
@@ -1145,6 +2019,7 @@ rtinit(ifa, cmd, flags)
                         * it doesn't exist, we could just return at this point
                         * with an "ELSE" clause, but apparently not..
                         */
+                       lck_mtx_unlock(rt_mtx);
                        return (flags & RTF_HOST ? EHOSTUNREACH
                                                        : ENETUNREACH);
                }
@@ -1153,7 +2028,7 @@ rtinit(ifa, cmd, flags)
        /*
         * Do the actual request
         */
-       error = rtrequest(cmd, dst, ifa->ifa_addr, ifa->ifa_netmask,
+       error = rtrequest_locked(cmd, dst, ifa->ifa_addr, ifa->ifa_netmask,
                        flags | ifa->ifa_flags, &nrt);
        if (m)
                (void) m_free(m);
@@ -1166,10 +2041,9 @@ rtinit(ifa, cmd, flags)
                 * notify any listenning routing agents of the change
                 */
                rt_newaddrmsg(cmd, ifa, error, nrt);
-               if (rt->rt_refcnt <= 0) {
-                       rt->rt_refcnt++; /* need a 1->0 transition to free */
-                       rtfree(rt);
-               }
+               if (use_routegenid)
+                       route_generation++;
+               rtfree_locked(rt);
        }
 
        /*
@@ -1177,10 +2051,6 @@ rtinit(ifa, cmd, flags)
         * We need to sanity check the result.
         */
        if (cmd == RTM_ADD && error == 0 && (rt = nrt)) {
-               /*
-                * We just wanted to add it.. we don't actually need a reference
-                */
-               rtunref(rt);
                /*
                 * If it came back with an unexpected interface, then it must
                 * have already existed or something. (XXX)
@@ -1206,9 +2076,6 @@ rtinit(ifa, cmd, flags)
                         * we are adding.
                         */
                        rt->rt_ifp = ifa->ifa_ifp;
-#ifdef __APPLE__
-                       rt->rt_dlt = ifa->ifa_dlt;      /* dl_tag */
-#endif
                        rt->rt_rmx.rmx_mtu = ifa->ifa_ifp->if_mtu;      /*XXX*/
                        /*
                         * Now ask the protocol to check if it needs
@@ -1221,6 +2088,84 @@ rtinit(ifa, cmd, flags)
                 * notify any listenning routing agents of the change
                 */
                rt_newaddrmsg(cmd, ifa, error, nrt);
+               if (use_routegenid)
+                       route_generation++;
+               /*
+                * We just wanted to add it; we don't actually need a
+                * reference.  This will result in a route that's added
+                * to the routing table without a reference count.  The
+                * RTM_DELETE code will do the necessary step to adjust
+                * the reference count at deletion time.
+                */
+               rtunref(rt);
        }
        return (error);
 }
+
+struct rtentry *
+rte_alloc(void)
+{
+       if (rte_debug & RTD_DEBUG)
+               return (rte_alloc_debug());
+
+       return ((struct rtentry *)zalloc(rte_zone));
+}
+
+void
+rte_free(struct rtentry *p)
+{
+       if (rte_debug & RTD_DEBUG) {
+               rte_free_debug(p);
+               return;
+       }
+
+       if (p->rt_refcnt != 0)
+               panic("rte_free: rte=%p refcnt=%d non-zero\n", p, p->rt_refcnt);
+
+       zfree(rte_zone, p);
+}
+
+static inline struct rtentry *
+rte_alloc_debug(void)
+{
+       struct rtentry_dbg *rte;
+
+       rte = ((struct rtentry_dbg *)zalloc(rte_zone));
+       if (rte != NULL) {
+               bzero(rte, sizeof (*rte));
+               if (rte_debug & RTD_TRACE) {
+                       rte->rtd_alloc_thread = current_thread();
+                       (void) OSBacktrace(rte->rtd_alloc_stk_pc,
+                           RTD_TRSTACK_SIZE);
+               }
+               rte->rtd_inuse = RTD_INUSE;
+       }
+       return ((struct rtentry *)rte);
+}
+
+static inline void
+rte_free_debug(struct rtentry *p)
+{
+       struct rtentry_dbg *rte = (struct rtentry_dbg *)p;
+
+       if (p->rt_refcnt != 0)
+               panic("rte_free: rte=%p refcnt=%d\n", p, p->rt_refcnt);
+
+       if (rte->rtd_inuse == RTD_FREED)
+               panic("rte_free: double free rte=%p\n", rte);
+       else if (rte->rtd_inuse != RTD_INUSE)
+               panic("rte_free: corrupted rte=%p\n", rte);
+
+       bcopy((caddr_t)p, (caddr_t)&rte->rtd_entry_saved, sizeof (*p));
+       bzero((caddr_t)p, sizeof (*p));
+
+       rte->rtd_inuse = RTD_FREED;
+
+       if (rte_debug & RTD_TRACE) {
+               rte->rtd_free_thread = current_thread();
+               (void) OSBacktrace(rte->rtd_free_stk_pc, RTD_TRSTACK_SIZE);
+       }
+
+       if (!(rte_debug & RTD_NO_FREE))
+               zfree(rte_zone, p);
+}