]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/net/if.c
xnu-1699.32.7.tar.gz
[apple/xnu.git] / bsd / net / if.c
index 43b96dfffba096042ed77617cd58e41d57132237..595fcaea994c6467ab3ad9585a3a9b411135ba9c 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
 #include <sys/sockio.h>
 #include <sys/syslog.h>
 #include <sys/sysctl.h>
+#include <sys/mcache.h>
+#include <kern/zalloc.h>
 
 #include <machine/endian.h>
 
+#include <pexpert/pexpert.h>
+
 #include <net/if.h>
 #include <net/if_arp.h>
 #include <net/if_dl.h>
 #include <netinet/in.h>
 #include <netinet/in_var.h>
 #include <netinet/ip_var.h>
+#include <netinet/ip6.h>
 #if INET6
 #include <netinet6/in6_var.h>
 #include <netinet6/in6_ifattach.h>
+#include <netinet6/ip6_var.h>
 #endif
 #endif
 
-extern int dlil_multithreaded_input;
-extern struct dlil_threading_info *dlil_lo_thread_ptr;
-
 #if CONFIG_MACF_NET 
 #include <security/mac_framework.h>
 #endif
@@ -124,21 +127,29 @@ extern struct dlil_threading_info *dlil_lo_thread_ptr;
  * System initialization
  */
 
+/* Lock group and attribute for ifaddr lock */
+lck_attr_t     *ifa_mtx_attr;
+lck_grp_t      *ifa_mtx_grp;
+static lck_grp_attr_t  *ifa_mtx_grp_attr;
+
 static int ifconf(u_long cmd, user_addr_t ifrp, int * ret_space);
 static void if_qflush(struct ifqueue *);
 __private_extern__ void link_rtrequest(int, struct rtentry *, struct sockaddr *);
 void if_rtproto_del(struct ifnet *ifp, int protocol);
 
+static int if_addmulti_common(struct ifnet *, const struct sockaddr *,
+    struct ifmultiaddr **, int);
+static int if_delmulti_common(struct ifmultiaddr *, struct ifnet *,
+    const struct sockaddr *, int);
+
 static int if_rtmtu(struct radix_node *, void *);
 static void if_rtmtu_update(struct ifnet *);
 
-static struct  if_clone *if_clone_lookup(const char *, int *);
 #if IF_CLONE_LIST
 static int     if_clone_list(int count, int * total, user_addr_t dst);
 #endif /* IF_CLONE_LIST */
 
 MALLOC_DEFINE(M_IFADDR, "ifaddr", "interface address");
-MALLOC_DEFINE(M_IFMADDR, "ether_multi", "link-level multicast address");
 
 int    ifqmaxlen = IFQ_MAXLEN;
 struct ifnethead ifnet_head = TAILQ_HEAD_INITIALIZER(ifnet_head);
@@ -148,6 +159,50 @@ LIST_HEAD(, if_clone) if_cloners = LIST_HEAD_INITIALIZER(if_cloners);
 
 static struct ifaddr *ifa_ifwithnet_common(const struct sockaddr *,
     unsigned int);
+static void if_attach_ifa_common(struct ifnet *, struct ifaddr *, int);
+static void if_detach_ifa_common(struct ifnet *, struct ifaddr *, int);
+
+static void if_attach_ifma(struct ifnet *, struct ifmultiaddr *, int);
+static int if_detach_ifma(struct ifnet *, struct ifmultiaddr *, int);
+
+static struct ifmultiaddr *ifma_alloc(int);
+static void ifma_free(struct ifmultiaddr *);
+static void ifma_trace(struct ifmultiaddr *, int);
+
+#if DEBUG
+static unsigned int ifma_debug = 1;    /* debugging (enabled) */
+#else
+static unsigned int ifma_debug;                /* debugging (disabled) */
+#endif /* !DEBUG */
+static unsigned int ifma_size;         /* size of zone element */
+static struct zone *ifma_zone;         /* zone for ifmultiaddr */
+
+#define        IFMA_TRACE_HIST_SIZE    32      /* size of trace history */
+
+/* For gdb */
+__private_extern__ unsigned int ifma_trace_hist_size = IFMA_TRACE_HIST_SIZE;
+
+struct ifmultiaddr_dbg {
+       struct ifmultiaddr      ifma;                   /* ifmultiaddr */
+       u_int16_t               ifma_refhold_cnt;       /* # of ref */
+       u_int16_t               ifma_refrele_cnt;       /* # of rele */
+       /*
+        * Circular lists of IFA_ADDREF and IFA_REMREF callers.
+        */
+       ctrace_t                ifma_refhold[IFMA_TRACE_HIST_SIZE];
+       ctrace_t                ifma_refrele[IFMA_TRACE_HIST_SIZE];
+       /*
+        * Trash list linkage
+        */
+       TAILQ_ENTRY(ifmultiaddr_dbg) ifma_trash_link;
+};
+
+/* List of trash ifmultiaddr entries protected by ifma_trash_lock */
+static TAILQ_HEAD(, ifmultiaddr_dbg) ifma_trash_head;
+static decl_lck_mtx_data(, ifma_trash_lock);
+
+#define        IFMA_ZONE_MAX           64              /* maximum elements in zone */
+#define        IFMA_ZONE_NAME          "ifmultiaddr"   /* zone name */
 
 #if INET6
 /*
@@ -155,9 +210,35 @@ static struct ifaddr *ifa_ifwithnet_common(const struct sockaddr *,
  * should be more generalized?
  */
 extern void    nd6_setmtu(struct ifnet *);
+extern lck_mtx_t *nd6_mutex;
 #endif
 
-#define M_CLONE                M_IFADDR
+
+void
+ifa_init(void)
+{
+       /* Setup lock group and attribute for ifaddr */
+       ifa_mtx_grp_attr = lck_grp_attr_alloc_init();
+       ifa_mtx_grp = lck_grp_alloc_init("ifaddr", ifa_mtx_grp_attr);
+       ifa_mtx_attr = lck_attr_alloc_init();
+
+       PE_parse_boot_argn("ifa_debug", &ifma_debug, sizeof (ifma_debug));
+
+       ifma_size = (ifma_debug == 0) ? sizeof (struct ifmultiaddr) :
+           sizeof (struct ifmultiaddr_dbg);
+
+       ifma_zone = zinit(ifma_size, IFMA_ZONE_MAX * ifma_size, 0,
+           IFMA_ZONE_NAME);
+       if (ifma_zone == NULL) {
+               panic("%s: failed allocating %s", __func__, IFMA_ZONE_NAME);
+               /* NOTREACHED */
+       }
+       zone_change(ifma_zone, Z_EXPAND, TRUE);
+       zone_change(ifma_zone, Z_CALLERACCT, FALSE);
+
+       lck_mtx_init(&ifma_trash_lock, ifa_mtx_grp, ifa_mtx_attr);
+       TAILQ_INIT(&ifma_trash_head);
+}
 
 /*
  * Network interface utility routines.
@@ -171,45 +252,106 @@ struct ifaddr **ifnet_addrs;
 struct ifnet **ifindex2ifnet;
 
 __private_extern__ void
-if_attach_ifa(
-       struct ifnet *ifp,
-       struct ifaddr *ifa)
+if_attach_ifa(struct ifnet *ifp, struct ifaddr *ifa)
+{
+       if_attach_ifa_common(ifp, ifa, 0);
+}
+
+__private_extern__ void
+if_attach_link_ifa(struct ifnet *ifp, struct ifaddr *ifa)
+{
+       if_attach_ifa_common(ifp, ifa, 1);
+}
+
+static void
+if_attach_ifa_common(struct ifnet *ifp, struct ifaddr *ifa, int link)
 {
-       ifnet_lock_assert(ifp, LCK_MTX_ASSERT_OWNED);
-       if (ifa->ifa_debug & IFD_ATTACHED) {
-               panic("if_attach_ifa: Attempted to attach address that's already attached!\n");
+       ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
+       IFA_LOCK_ASSERT_HELD(ifa);
+
+       if (ifa->ifa_ifp != ifp) {
+               panic("%s: Mismatch ifa_ifp=%p != ifp=%p", __func__,
+                   ifa->ifa_ifp, ifp);
+               /* NOTREACHED */
+       } else if (ifa->ifa_debug & IFD_ATTACHED) {
+               panic("%s: Attempt to attach an already attached ifa=%p",
+                   __func__, ifa);
+               /* NOTREACHED */
+       } else if (link && !(ifa->ifa_debug & IFD_LINK)) {
+               panic("%s: Unexpected non-link address ifa=%p", __func__, ifa);
+               /* NOTREACHED */
+       } else if (!link && (ifa->ifa_debug & IFD_LINK)) {
+               panic("%s: Unexpected link address ifa=%p", __func__, ifa);
+               /* NOTREACHED */
        }
-       ifaref(ifa);
+       IFA_ADDREF_LOCKED(ifa);
        ifa->ifa_debug |= IFD_ATTACHED;
-       TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
+       if (link)
+               TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
+       else
+               TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link);
+
+       if (ifa->ifa_attached != NULL)
+               (*ifa->ifa_attached)(ifa);
 }
 
 __private_extern__ void
-if_detach_ifa(
-       struct ifnet *ifp,
-       struct ifaddr *ifa)
-{
-       ifnet_lock_assert(ifp, LCK_MTX_ASSERT_OWNED);
-#if 1
-       /* Debugging code */
-       if ((ifa->ifa_debug & IFD_ATTACHED) == 0) {
-               printf("if_detach_ifa: ifa is not attached to any interface! flags=%u\n", ifa->ifa_debug);
-               return;
-       }
-       else {
+if_detach_ifa(struct ifnet *ifp, struct ifaddr *ifa)
+{
+       if_detach_ifa_common(ifp, ifa, 0);
+}
+
+__private_extern__ void
+if_detach_link_ifa(struct ifnet *ifp, struct ifaddr *ifa)
+{
+       if_detach_ifa_common(ifp, ifa, 1);
+}
+
+static void
+if_detach_ifa_common(struct ifnet *ifp, struct ifaddr *ifa, int link)
+{
+       ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
+       IFA_LOCK_ASSERT_HELD(ifa);
+
+       if (link && !(ifa->ifa_debug & IFD_LINK)) {
+               panic("%s: Unexpected non-link address ifa=%p", __func__, ifa);
+               /* NOTREACHED */
+       } else if (link && ifa != TAILQ_FIRST(&ifp->if_addrhead)) {
+               panic("%s: Link address ifa=%p not first", __func__, ifa);
+               /* NOTREACHED */
+       } else if (!link && (ifa->ifa_debug & IFD_LINK)) {
+               panic("%s: Unexpected link address ifa=%p", __func__, ifa);
+               /* NOTREACHED */
+       } else if (!(ifa->ifa_debug & IFD_ATTACHED)) {
+               panic("%s: Attempt to detach an unattached address ifa=%p",
+                   __func__, ifa);
+               /* NOTREACHED */
+       } else if (ifa->ifa_ifp != ifp) {
+               panic("%s: Mismatch ifa_ifp=%p, ifp=%p", __func__,
+                   ifa->ifa_ifp, ifp);
+               /* NOTREACHED */
+       } else if (ifa->ifa_debug & IFD_DEBUG) {
                struct ifaddr *ifa2;
                TAILQ_FOREACH(ifa2, &ifp->if_addrhead, ifa_link) {
                        if (ifa2 == ifa)
                                break;
                }
                if (ifa2 != ifa) {
-                       printf("if_detach_ifa: Attempted to detach IFA that was not attached!\n");
-               }       
+                       panic("%s: Attempt to detach a stray address ifa=%p",
+                           __func__, ifa);
+                       /* NOTREACHED */
+               }
        }
-#endif
        TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
+       /* This must not be the last reference to the ifaddr */
+       if (IFA_REMREF_LOCKED(ifa) == NULL) {
+               panic("%s: unexpected (missing) refcnt ifa=%p", __func__, ifa);
+               /* NOTREACHED */
+       }
        ifa->ifa_debug &= ~IFD_ATTACHED;
-       ifafree(ifa);
+
+       if (ifa->ifa_detached != NULL)
+               (*ifa->ifa_detached)(ifa);
 }
 
 #define INITIAL_IF_INDEXLIM    8
@@ -287,12 +429,13 @@ if_next_index(void)
  * Create a clone network interface.
  */
 static int
-if_clone_create(char *name, int len)
+if_clone_create(char *name, int len, void *params)
 {
        struct if_clone *ifc;
        char *dp;
-       int wildcard, bytoff, bitoff;
-       int unit;
+       int wildcard;
+       u_int32_t bytoff, bitoff;
+       u_int32_t unit;
        int err;
 
        ifc = if_clone_lookup(name, &unit);
@@ -303,7 +446,7 @@ if_clone_create(char *name, int len)
                return (EEXIST);
 
        bytoff = bitoff = 0;
-       wildcard = (unit < 0);
+       wildcard = (unit == UINT32_MAX);
        /*
         * Find a free unit if none was given.
         */
@@ -321,7 +464,7 @@ if_clone_create(char *name, int len)
        if (unit > ifc->ifc_maxunit)
                return (ENXIO);
 
-       err = (*ifc->ifc_create)(ifc, unit);
+       err = (*ifc->ifc_create)(ifc, unit, params);
        if (err != 0)
                return (err);
 
@@ -347,7 +490,8 @@ if_clone_create(char *name, int len)
                         * there's no straightforward way to recover if
                         * it happens.
                         */
-                       panic("if_clone_create(): interface name too long");
+                       panic("%s: interface name too long", __func__);
+                       /* NOTREACHED */
                }
 
        }
@@ -364,7 +508,7 @@ if_clone_destroy(const char *name)
        struct if_clone *ifc;
        struct ifnet *ifp;
        int bytoff, bitoff;
-       int unit;
+       u_int32_t unit;
 
        ifc = if_clone_lookup(name, &unit);
        if (ifc == NULL)
@@ -397,8 +541,8 @@ if_clone_destroy(const char *name)
  * Look up a network interface cloner.
  */
 
-static struct if_clone *
-if_clone_lookup(const char *name, int *unitp)
+__private_extern__ struct if_clone *
+if_clone_lookup(const char *name, u_int32_t *unitp)
 {
        struct if_clone *ifc;
        const char *cp;
@@ -419,7 +563,7 @@ if_clone_lookup(const char *name, int *unitp)
 
  found_name:
        if (*cp == '\0') {
-               i = -1;
+               i = 0xffff;
        } else {
                for (i = 0; *cp != '\0'; cp++) {
                        if (*cp < '0' || *cp > '9') {
@@ -444,7 +588,7 @@ if_clone_attach(struct if_clone *ifc)
        int bytoff, bitoff;
        int err;
        int len, maxclone;
-       int unit;
+       u_int32_t unit;
 
        KASSERT(ifc->ifc_minifs - 1 <= ifc->ifc_maxunit,
            ("%s: %s requested more units then allowed (%d > %d)",
@@ -467,7 +611,7 @@ if_clone_attach(struct if_clone *ifc)
        if_cloners_count++;
 
        for (unit = 0; unit < ifc->ifc_minifs; unit++) {
-               err = (*ifc->ifc_create)(ifc, unit);
+               err = (*ifc->ifc_create)(ifc, unit, NULL);
                KASSERT(err == 0,
                    ("%s: failed to create required interface %s%d",
                    __func__, ifc->ifc_name, unit));
@@ -549,36 +693,72 @@ ifa_foraddr_scoped(unsigned int addr, unsigned int scope)
 
        lck_rw_lock_shared(in_ifaddr_rwlock);
        TAILQ_FOREACH(ia, INADDR_HASH(addr), ia_hash) {
+               IFA_LOCK_SPIN(&ia->ia_ifa);
                if (ia->ia_addr.sin_addr.s_addr == addr &&
-                   (scope == IFSCOPE_NONE || ia->ia_ifp->if_index == scope))
+                   (scope == IFSCOPE_NONE || ia->ia_ifp->if_index == scope)) {
+                       IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for caller */
+                       IFA_UNLOCK(&ia->ia_ifa);
                        break;
+               }
+               IFA_UNLOCK(&ia->ia_ifa);
        }
-       if (ia != NULL)
-               ifaref(&ia->ia_ifa);
        lck_rw_done(in_ifaddr_rwlock);
        return (ia);
 }
 
+#if INET6
+/*
+ * Similar to ifa_foraddr, except that this for IPv6.
+ */
+__private_extern__ struct in6_ifaddr *
+ifa_foraddr6(struct in6_addr *addr6)
+{
+       return (ifa_foraddr6_scoped(addr6, IFSCOPE_NONE));
+}
+
+__private_extern__ struct in6_ifaddr *
+ifa_foraddr6_scoped(struct in6_addr *addr6, unsigned int scope)
+{
+       struct in6_ifaddr *ia = NULL;
+
+       lck_rw_lock_shared(&in6_ifaddr_rwlock);
+       for (ia = in6_ifaddrs; ia; ia = ia->ia_next) {
+               IFA_LOCK(&ia->ia_ifa);
+               if (IN6_ARE_ADDR_EQUAL(&ia->ia_addr.sin6_addr, addr6) &&
+                   (scope == IFSCOPE_NONE || ia->ia_ifp->if_index == scope)) {
+                       IFA_ADDREF_LOCKED(&ia->ia_ifa); /* for caller */
+                       IFA_UNLOCK(&ia->ia_ifa);
+                       break;
+               }
+               IFA_UNLOCK(&ia->ia_ifa);
+       }
+       lck_rw_done(&in6_ifaddr_rwlock);
+
+       return (ia);
+}
+#endif /* INET6 */
+
 /*
  * Return the first (primary) address of a given family on an interface.
  */
 __private_extern__ struct ifaddr *
 ifa_ifpgetprimary(struct ifnet *ifp, int family)
 {
-       struct ifaddr *ifa0 = NULL, *ifa;
+       struct ifaddr *ifa;
 
        ifnet_lock_shared(ifp);
        TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
-               if (ifa->ifa_addr->sa_family == family && ifa0 == NULL) {
-                       ifa0 = ifa;
+               IFA_LOCK_SPIN(ifa);
+               if (ifa->ifa_addr->sa_family == family) {
+                       IFA_ADDREF_LOCKED(ifa); /* for caller */
+                       IFA_UNLOCK(ifa);
                        break;
                }
+               IFA_UNLOCK(ifa);
        }
-       if (ifa0 != NULL)
-               ifaref(ifa0);
        ifnet_lock_done(ifp);
 
-       return (ifa0);
+       return (ifa);
 }
 
 /*
@@ -586,75 +766,89 @@ ifa_ifpgetprimary(struct ifnet *ifp, int family)
  */
 /*ARGSUSED*/
 struct ifaddr *
-ifa_ifwithaddr(
-       const struct sockaddr *addr)
+ifa_ifwithaddr(const struct sockaddr *addr)
 {
        struct ifnet *ifp;
        struct ifaddr *ifa;
        struct ifaddr *result = NULL;
 
-#define        equal(a1, a2) \
-  (bcmp((const void*)(a1), (const void*)(a2), ((const struct sockaddr *)(a1))->sa_len) == 0)
-  
+#define        equal(a1, a2)                                                   \
+       (bcmp((const void*)(a1), (const void*)(a2),                     \
+           ((const struct sockaddr *)(a1))->sa_len) == 0)
+
        ifnet_head_lock_shared();
-       for (ifp = ifnet_head.tqh_first; ifp && !result; ifp = ifp->if_link.tqe_next) {
+       for (ifp = ifnet_head.tqh_first; ifp && !result;
+           ifp = ifp->if_link.tqe_next) {
                ifnet_lock_shared(ifp);
                for (ifa = ifp->if_addrhead.tqh_first; ifa;
-                        ifa = ifa->ifa_link.tqe_next) {
-                       if (ifa->ifa_addr->sa_family != addr->sa_family)
+                   ifa = ifa->ifa_link.tqe_next) {
+                       IFA_LOCK_SPIN(ifa);
+                       if (ifa->ifa_addr->sa_family != addr->sa_family) {
+                               IFA_UNLOCK(ifa);
                                continue;
+                       }
                        if (equal(addr, ifa->ifa_addr)) {
                                result = ifa;
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
                        }
-                       if ((ifp->if_flags & IFF_BROADCAST) && ifa->ifa_broadaddr &&
-                               /* IP6 doesn't have broadcast */
-                               ifa->ifa_broadaddr->sa_len != 0 &&
-                               equal(ifa->ifa_broadaddr, addr)) {
+                       if ((ifp->if_flags & IFF_BROADCAST) &&
+                           ifa->ifa_broadaddr != NULL &&
+                           /* IP6 doesn't have broadcast */
+                           ifa->ifa_broadaddr->sa_len != 0 &&
+                           equal(ifa->ifa_broadaddr, addr)) {
                                result = ifa;
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
                        }
+                       IFA_UNLOCK(ifa);
                }
-               if (result)
-                       ifaref(result);
                ifnet_lock_done(ifp);
        }
        ifnet_head_done();
-       
-       return result;
+
+       return (result);
 }
 /*
  * Locate the point to point interface with a given destination address.
  */
 /*ARGSUSED*/
 struct ifaddr *
-ifa_ifwithdstaddr(
-       const struct sockaddr *addr)
+ifa_ifwithdstaddr(const struct sockaddr *addr)
 {
        struct ifnet *ifp;
        struct ifaddr *ifa;
        struct ifaddr *result = NULL;
 
        ifnet_head_lock_shared();
-       for (ifp = ifnet_head.tqh_first; ifp && !result; ifp = ifp->if_link.tqe_next) {
-           if (ifp->if_flags & IFF_POINTOPOINT) {
+       for (ifp = ifnet_head.tqh_first; ifp && !result;
+           ifp = ifp->if_link.tqe_next) {
+           if ((ifp->if_flags & IFF_POINTOPOINT)) {
                        ifnet_lock_shared(ifp);
                        for (ifa = ifp->if_addrhead.tqh_first; ifa;
-                                ifa = ifa->ifa_link.tqe_next) {
-                               if (ifa->ifa_addr->sa_family != addr->sa_family)
+                           ifa = ifa->ifa_link.tqe_next) {
+                               IFA_LOCK_SPIN(ifa);
+                               if (ifa->ifa_addr->sa_family !=
+                                   addr->sa_family) {
+                                       IFA_UNLOCK(ifa);
                                        continue;
-                               if (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)) {
+                               }
+                               if (ifa->ifa_dstaddr &&
+                                   equal(addr, ifa->ifa_dstaddr)) {
                                        result = ifa;
+                                       IFA_ADDREF_LOCKED(ifa); /* for caller */
+                                       IFA_UNLOCK(ifa);
                                        break;
                                }
+                               IFA_UNLOCK(ifa);
                        }
-                       if (result)
-                               ifaref(result);
                        ifnet_lock_done(ifp);
                }
        }
        ifnet_head_done();
-       return result;
+       return (result);
 }
 
 /*
@@ -687,10 +881,15 @@ ifa_ifwithaddr_scoped(const struct sockaddr *addr, unsigned int ifscope)
                ifnet_lock_shared(ifp);
                for (ifa = ifp->if_addrhead.tqh_first; ifa != NULL;
                    ifa = ifa->ifa_link.tqe_next) {
-                       if (ifa->ifa_addr->sa_family != addr->sa_family)
+                       IFA_LOCK_SPIN(ifa);
+                       if (ifa->ifa_addr->sa_family != addr->sa_family) {
+                               IFA_UNLOCK(ifa);
                                continue;
+                       }
                        if (equal(addr, ifa->ifa_addr)) {
                                result = ifa;
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
                        }
                        if ((ifp->if_flags & IFF_BROADCAST) &&
@@ -699,11 +898,12 @@ ifa_ifwithaddr_scoped(const struct sockaddr *addr, unsigned int ifscope)
                            ifa->ifa_broadaddr->sa_len != 0 &&
                            equal(ifa->ifa_broadaddr, addr)) {
                                result = ifa;
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
                        }
+                       IFA_UNLOCK(ifa);
                }
-               if (result != NULL)
-                       ifaref(result);
                ifnet_lock_done(ifp);
        }
        ifnet_head_done();
@@ -732,11 +932,17 @@ ifa_ifwithnet_common(const struct sockaddr *addr, unsigned int ifscope)
 {
        struct ifnet *ifp;
        struct ifaddr *ifa = NULL;
-       struct ifaddr *ifa_maybe = (struct ifaddr *) 0;
+       struct ifaddr *ifa_maybe = NULL;
        u_int af = addr->sa_family;
        const char *addr_data = addr->sa_data, *cplim;
 
-       if (!ip_doscopedroute || addr->sa_family != AF_INET)
+#if INET6
+       if ((af != AF_INET && af != AF_INET6) ||
+           (af == AF_INET && !ip_doscopedroute) ||
+           (af == AF_INET6 && !ip6_doscopedroute))
+#else
+       if (af != AF_INET || !ip_doscopedroute)
+#endif /* !INET6 */
                ifscope = IFSCOPE_NONE;
 
        ifnet_head_lock_shared();
@@ -745,15 +951,14 @@ ifa_ifwithnet_common(const struct sockaddr *addr, unsigned int ifscope)
         * so do that if we can.
         */
        if (af == AF_LINK) {
-           const struct sockaddr_dl *sdl = (const struct sockaddr_dl *)addr;
-           if (sdl->sdl_index && sdl->sdl_index <= if_index) {
+               const struct sockaddr_dl *sdl = (const struct sockaddr_dl *)addr;
+               if (sdl->sdl_index && sdl->sdl_index <= if_index) {
                        ifa = ifnet_addrs[sdl->sdl_index - 1];
-       
-                       if (ifa)
-                               ifaref(ifa);
-                       
+                       if (ifa != NULL)
+                               IFA_ADDREF(ifa);
+
                        ifnet_head_done();
-                       return ifa;
+                       return (ifa);
                }
        }
 
@@ -767,15 +972,19 @@ ifa_ifwithnet_common(const struct sockaddr *addr, unsigned int ifscope)
                     ifa = ifa->ifa_link.tqe_next) {
                        const char *cp, *cp2, *cp3;
 
-                       if (ifa->ifa_addr->sa_family != af)
-next:                          continue;
+                       IFA_LOCK(ifa);
+                       if (ifa->ifa_addr == NULL ||
+                           ifa->ifa_addr->sa_family != af) {
+next:
+                               IFA_UNLOCK(ifa);
+                               continue;
+                       }
 #ifndef __APPLE__
 /* This breaks tunneling application trying to install a route with
  * a specific subnet and the local address as the destination
  * It's breaks binary compatibility with previous version of MacOS X
  */
                        if (
 #if INET6 /* XXX: for maching gif tunnel dst as routing entry gateway */
                            addr->sa_family != AF_INET6 &&
 #endif
@@ -788,10 +997,13 @@ next:                             continue;
                                 * The trouble is that we don't know the
                                 * netmask for the remote end.
                                 */
-                               if (ifa->ifa_dstaddr != 0
-                                   && equal(addr, ifa->ifa_dstaddr)) {
-                                   break;
-                               }
+                               if (ifa->ifa_dstaddr != 0 &&
+                                   equal(addr, ifa->ifa_dstaddr)) {
+                                       IFA_ADDREF_LOCKED(ifa);
+                                       IFA_UNLOCK(ifa);
+                                       break;
+                               }
+                               IFA_UNLOCK(ifa);
                        } else
 #endif /* __APPLE__*/
                        {
@@ -800,8 +1012,10 @@ next:                             continue;
                                 * find using a matching interface.
                                 */
                                if (ifscope != IFSCOPE_NONE &&
-                                   ifp->if_index != ifscope)
+                                   ifp->if_index != ifscope) {
+                                       IFA_UNLOCK(ifa);
                                        continue;
+                               }
 
                                /*
                                 * Scan all the bits in the ifa's address.
@@ -810,8 +1024,10 @@ next:                             continue;
                                 * to see if it really matters.
                                 * (A byte at a time)
                                 */
-                               if (ifa->ifa_netmask == 0)
+                               if (ifa->ifa_netmask == 0) {
+                                       IFA_UNLOCK(ifa);
                                        continue;
+                               }
                                cp = addr_data;
                                cp2 = ifa->ifa_addr->sa_data;
                                cp3 = ifa->ifa_netmask->sa_data;
@@ -827,40 +1043,33 @@ next:                            continue;
                                 * before continuing to search
                                 * for an even better one.
                                 */
-                               if (ifa_maybe == 0 ||
+                               if (ifa_maybe == NULL ||
                                    rn_refines((caddr_t)ifa->ifa_netmask,
                                    (caddr_t)ifa_maybe->ifa_netmask)) {
-                                       ifaref(ifa);
-                                       if (ifa_maybe)
-                                               ifafree(ifa_maybe);
+                                       IFA_ADDREF_LOCKED(ifa); /* ifa_maybe */
+                                       IFA_UNLOCK(ifa);
+                                       if (ifa_maybe != NULL)
+                                               IFA_REMREF(ifa_maybe);
                                        ifa_maybe = ifa;
+                               } else {
+                                       IFA_UNLOCK(ifa);
                                }
                        }
+                       IFA_LOCK_ASSERT_NOTHELD(ifa);
                }
-               
-               if (ifa) {
-                       ifaref(ifa);
-               }
-               
-               /*
-                * ifa is set if we found an exact match.
-                * take a reference to the ifa before
-                * releasing the ifp lock
-                */
                ifnet_lock_done(ifp);
-               
-               if (ifa) {
+
+               if (ifa != NULL)
                        break;
-               }
        }
        ifnet_head_done();
-       if (!ifa)
+
+       if (ifa == NULL)
                ifa = ifa_maybe;
-       else if (ifa_maybe) {
-               ifafree(ifa_maybe);
-               ifa_maybe = NULL;
-       }
-       return ifa;
+       else if (ifa_maybe != NULL)
+               IFA_REMREF(ifa_maybe);
+
+       return (ifa);
 }
 
 /*
@@ -868,9 +1077,7 @@ next:                              continue;
  * a given address.
  */
 struct ifaddr *
-ifaof_ifpforaddr(
-       const struct sockaddr *addr,
-       struct ifnet *ifp)
+ifaof_ifpforaddr(const struct sockaddr *addr, struct ifnet *ifp)
 {
        struct ifaddr *ifa = NULL;
        const char *cp, *cp2, *cp3;
@@ -881,55 +1088,80 @@ ifaof_ifpforaddr(
 
        if (af >= AF_MAX)
                return (NULL);
-       
+
        ifnet_lock_shared(ifp);
        for (ifa = ifp->if_addrhead.tqh_first; ifa;
             ifa = ifa->ifa_link.tqe_next) {
-               if (ifa->ifa_addr->sa_family != af)
+               IFA_LOCK(ifa);
+               if (ifa->ifa_addr->sa_family != af) {
+                       IFA_UNLOCK(ifa);
                        continue;
-               if (ifa_maybe == 0)
+               }
+               if (ifa_maybe == NULL) {
+                       IFA_ADDREF_LOCKED(ifa); /* for ifa_maybe */
                        ifa_maybe = ifa;
+               }
                if (ifa->ifa_netmask == 0) {
-                       if (equal(addr, ifa->ifa_addr) ||
-                           (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)))
-                           break;
+                       if (equal(addr, ifa->ifa_addr) || (ifa->ifa_dstaddr &&
+                           equal(addr, ifa->ifa_dstaddr))) {
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
+                               break;
+                       }
+                       IFA_UNLOCK(ifa);
                        continue;
                }
                if (ifp->if_flags & IFF_POINTOPOINT) {
-                       if (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr))
+                       if (ifa->ifa_dstaddr && equal(addr, ifa->ifa_dstaddr)) {
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
+                       }
                } else {
-                       if (equal(addr, ifa->ifa_addr)) {
+                       if (equal(addr, ifa->ifa_addr)) {
                                /* exact match */
+                               IFA_ADDREF_LOCKED(ifa); /* for caller */
+                               IFA_UNLOCK(ifa);
                                break;
                        }
                        cp = addr->sa_data;
                        cp2 = ifa->ifa_addr->sa_data;
                        cp3 = ifa->ifa_netmask->sa_data;
-                       cplim = ifa->ifa_netmask->sa_len + (char *)ifa->ifa_netmask;
+                       cplim = ifa->ifa_netmask->sa_len +
+                           (char *)ifa->ifa_netmask;
                        for (; cp3 < cplim; cp3++)
                                if ((*cp++ ^ *cp2++) & *cp3)
                                        break;
                        if (cp3 == cplim) {
                                /* subnet match */
                                if (better_ifa_maybe == NULL) {
+                                       /* for better_ifa_maybe */
+                                       IFA_ADDREF_LOCKED(ifa);
                                        better_ifa_maybe = ifa;
                                }
                        }
                }
+               IFA_UNLOCK(ifa);
        }
-       
+
        if (ifa == NULL) {
                if (better_ifa_maybe != NULL) {
                        ifa = better_ifa_maybe;
+                       better_ifa_maybe = NULL;
                } else {
                        ifa = ifa_maybe;
+                       ifa_maybe = NULL;
                }
        }
-       if (ifa) ifaref(ifa);
-       
+
        ifnet_lock_done(ifp);
-       return ifa;
+
+       if (better_ifa_maybe != NULL)
+               IFA_REMREF(better_ifa_maybe);
+       if (ifa_maybe != NULL)
+               IFA_REMREF(ifa_maybe);
+
+       return (ifa);
 }
 
 #include <net/route.h>
@@ -945,6 +1177,7 @@ link_rtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa)
        struct ifaddr *ifa;
        struct sockaddr *dst;
        struct ifnet *ifp;
+       void (*ifa_rtrequest)(int, struct rtentry *, struct sockaddr *);
 
        lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED);
        RT_LOCK_ASSERT_HELD(rt);
@@ -952,12 +1185,19 @@ link_rtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa)
        if (cmd != RTM_ADD || ((ifa = rt->rt_ifa) == 0) ||
            ((ifp = ifa->ifa_ifp) == 0) || ((dst = rt_key(rt)) == 0))
                return;
+
+       /* Become a regular mutex, just in case */
+       RT_CONVERT_LOCK(rt);
+
        ifa = ifaof_ifpforaddr(dst, ifp);
        if (ifa) {
                rtsetifa(rt, ifa);
-               if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
-                       ifa->ifa_rtrequest(cmd, rt, sa);
-               ifafree(ifa);
+               IFA_LOCK_SPIN(ifa);
+               ifa_rtrequest = ifa->ifa_rtrequest;
+               IFA_UNLOCK(ifa);
+               if (ifa_rtrequest != NULL && ifa_rtrequest != link_rtrequest)
+                       ifa_rtrequest(cmd, rt, sa);
+               IFA_REMREF(ifa);
        }
 }
 
@@ -1089,19 +1329,19 @@ ifunit(const char *name)
 
        len = strlen(name);
        if (len < 2 || len > IFNAMSIZ)
-               return NULL;
+               return (NULL);
        cp = name + len - 1;
        c = *cp;
        if (c < '0' || c > '9')
-               return NULL;            /* trailing garbage */
+               return (NULL);          /* trailing garbage */
        unit = 0;
        m = 1;
        do {
                if (cp == name)
-                       return NULL;    /* no interface name */
+                       return (NULL);  /* no interface name */
                unit += (c - '0') * m;
                if (unit > 1000000)
-                       return NULL;    /* number is unreasonable */
+                       return (NULL);  /* number is unreasonable */
                m *= 10;
                c = *--cp;
        } while (c >= '0' && c <= '9');
@@ -1135,7 +1375,7 @@ if_withname(struct sockaddr *sa)
 
        if ( (sa->sa_family != AF_LINK) || (sdl->sdl_nlen == 0) ||
             (sdl->sdl_nlen > IFNAMSIZ) )
-               return NULL;
+               return (NULL);
 
        /*
         * ifunit wants a null-terminated name.  It may not be null-terminated
@@ -1146,7 +1386,7 @@ if_withname(struct sockaddr *sa)
 
        bcopy(sdl->sdl_data, ifname, sdl->sdl_nlen);
        ifname[sdl->sdl_nlen] = '\0';
-       return ifunit(ifname);
+       return (ifunit(ifname));
 }
 
 
@@ -1164,6 +1404,8 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
        struct kev_msg        ev_msg;
        struct net_event_data ev_data;
 
+       bzero(&ev_data, sizeof(struct net_event_data));
+       bzero(&ev_msg, sizeof(struct kev_msg));
        switch (cmd) {
        case OSIOCGIFCONF32:
        case SIOCGIFCONF32: {
@@ -1182,13 +1424,17 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
        ifr = (struct ifreq *)data;
        switch (cmd) {
        case SIOCIFCREATE:
+       case SIOCIFCREATE2:
+                error = proc_suser(p);
+                if (error)
+                        return (error);
+                return if_clone_create(ifr->ifr_name, sizeof(ifr->ifr_name),
+                        cmd == SIOCIFCREATE2 ? ifr->ifr_data : NULL);
        case SIOCIFDESTROY:
                error = proc_suser(p);
                if (error)
                        return (error);
-               return ((cmd == SIOCIFCREATE) ?
-                       if_clone_create(ifr->ifr_name, sizeof(ifr->ifr_name)) :
-                       if_clone_destroy(ifr->ifr_name));
+               return if_clone_destroy(ifr->ifr_name);
 #if IF_CLONE_LIST
        case SIOCIFGCLONERS32: {
                struct if_clonereq32 *ifcr = (struct if_clonereq32 *)data;
@@ -1206,22 +1452,33 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 #endif /* IF_CLONE_LIST */
        }
 
+       /*
+        * ioctls which require ifp.  Note that we acquire dlil_ifnet_lock
+        * here to ensure that the ifnet, if found, has been fully attached.
+        */
+       dlil_if_lock();
        ifp = ifunit(ifr->ifr_name);
-       if (ifp == 0)
+       dlil_if_unlock();
+       if (ifp == NULL)
                return (ENXIO);
-       switch (cmd) {
 
+       switch (cmd) {
        case SIOCGIFFLAGS:
                ifnet_lock_shared(ifp);
                ifr->ifr_flags = ifp->if_flags;
                ifnet_lock_done(ifp);
                break;
 
+       case SIOCGIFCAP:
+               ifnet_lock_shared(ifp);
+               ifr->ifr_reqcap = ifp->if_capabilities;
+               ifr->ifr_curcap = ifp->if_capenable;
+               ifnet_lock_done(ifp);
+               break;
+
 #if CONFIG_MACF_NET
        case SIOCGIFMAC:
                error = mac_ifnet_label_get(kauth_cred_get(), ifr, ifp);
-               if (error)
-                       return (error);
                break;
 #endif
        case SIOCGIFMETRIC:
@@ -1244,19 +1501,27 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 
        case SIOCSIFFLAGS:
                error = proc_suser(p);
-               if (error)
-                       return (error);
+               if (error != 0)
+                       break;
 
-               ifnet_set_flags(ifp, ifr->ifr_flags, (u_int16_t)~IFF_CANTCHANGE);
+               (void) ifnet_set_flags(ifp, ifr->ifr_flags,
+                   (u_int16_t)~IFF_CANTCHANGE);
 
-               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                       cmd, data);
+               /*
+                * Note that we intentionally ignore any error from below
+                * for the SIOCSIFFLAGS case.
+                */
+               (void) ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
 
-               /* Send the event even upon error from the driver because we changed the flags */
+               /*
+                * Send the event even upon error from the driver because
+                * we changed the flags.
+                */
                ev_msg.vendor_code    = KEV_VENDOR_APPLE;
                ev_msg.kev_class      = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
-               
+
                ev_msg.event_code = KEV_DL_SIFFLAGS;
                strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
                ev_data.if_family = ifp->if_family;
@@ -1269,24 +1534,37 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
                ifnet_touch_lastchange(ifp);
                break;
 
+       case SIOCSIFCAP:
+               error = proc_suser(p);
+               if (error != 0)
+                       break;
+
+               if ((ifr->ifr_reqcap & ~ifp->if_capabilities)) {
+                       error = EINVAL;
+                       break;
+               }
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+
+               ifnet_touch_lastchange(ifp);
+               break;
+
 #if CONFIG_MACF_NET
        case SIOCSIFMAC:
                error = mac_ifnet_label_set(kauth_cred_get(), ifr, ifp);
-               if (error)
-                       return (error);
                break;
 #endif
        case SIOCSIFMETRIC:
                error = proc_suser(p);
-               if (error)
-                       return (error);
-               ifp->if_metric = ifr->ifr_metric;
+               if (error != 0)
+                       break;
 
+               ifp->if_metric = ifr->ifr_metric;
 
                ev_msg.vendor_code    = KEV_VENDOR_APPLE;
                ev_msg.kev_class      = KEV_NETWORK_CLASS;
                ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
-       
+
                ev_msg.event_code = KEV_DL_SIFMETRICS;
                strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
                ev_data.if_family = ifp->if_family;
@@ -1302,144 +1580,165 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 
        case SIOCSIFPHYS:
                error = proc_suser(p);
-               if (error)
-                       return error;
+               if (error != 0)
+                       break;
 
-               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                       cmd, data);
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+               if (error != 0)
+                       break;
 
-               if (error == 0) {
-                       ev_msg.vendor_code    = KEV_VENDOR_APPLE;
-                       ev_msg.kev_class      = KEV_NETWORK_CLASS;
-                       ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
-
-                       ev_msg.event_code = KEV_DL_SIFPHYS;
-                       strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
-                       ev_data.if_family = ifp->if_family;
-                       ev_data.if_unit   = (u_int32_t) ifp->if_unit;
-                       ev_msg.dv[0].data_length = sizeof(struct net_event_data);
-                       ev_msg.dv[0].data_ptr    = &ev_data;
-                       ev_msg.dv[1].data_length = 0;
-                       kev_post_msg(&ev_msg);
-
-                       ifnet_touch_lastchange(ifp);
-               }
-               return(error);
+               ev_msg.vendor_code    = KEV_VENDOR_APPLE;
+               ev_msg.kev_class      = KEV_NETWORK_CLASS;
+               ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
+
+               ev_msg.event_code = KEV_DL_SIFPHYS;
+               strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
+               ev_data.if_family = ifp->if_family;
+               ev_data.if_unit   = (u_int32_t) ifp->if_unit;
+               ev_msg.dv[0].data_length = sizeof(struct net_event_data);
+               ev_msg.dv[0].data_ptr    = &ev_data;
+               ev_msg.dv[1].data_length = 0;
+               kev_post_msg(&ev_msg);
+
+               ifnet_touch_lastchange(ifp);
+               break;
 
        case SIOCSIFMTU:
        {
                u_int32_t oldmtu = ifp->if_mtu;
 
                error = proc_suser(p);
-               if (error)
-                       return (error);
-               if (ifp->if_ioctl == NULL)
-                       return (EOPNOTSUPP);
-               if (ifr->ifr_mtu < IF_MINMTU || ifr->ifr_mtu > IF_MAXMTU)
-                       return (EINVAL);
-
-               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                       cmd, data);
+               if (error != 0)
+                       break;
 
-               if (error == 0) {
-                    ev_msg.vendor_code    = KEV_VENDOR_APPLE;
-                    ev_msg.kev_class      = KEV_NETWORK_CLASS;
-                    ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
-       
-                    ev_msg.event_code = KEV_DL_SIFMTU;
-                    strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
-                    ev_data.if_family = ifp->if_family;
-                    ev_data.if_unit   = (u_int32_t) ifp->if_unit;
-                    ev_msg.dv[0].data_length = sizeof(struct net_event_data);
-                    ev_msg.dv[0].data_ptr    = &ev_data;
-                    ev_msg.dv[1].data_length = 0;
-                    kev_post_msg(&ev_msg);
-
-                       ifnet_touch_lastchange(ifp);
-                       rt_ifmsg(ifp);
+               if (ifp->if_ioctl == NULL) {
+                       error = EOPNOTSUPP;
+                       break;
+               }
+               if (ifr->ifr_mtu < IF_MINMTU || ifr->ifr_mtu > IF_MAXMTU) {
+                       error = EINVAL;
+                       break;
                }
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+               if (error != 0)
+                       break;
+
+               ev_msg.vendor_code    = KEV_VENDOR_APPLE;
+               ev_msg.kev_class      = KEV_NETWORK_CLASS;
+               ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
+
+               ev_msg.event_code = KEV_DL_SIFMTU;
+               strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
+               ev_data.if_family = ifp->if_family;
+               ev_data.if_unit   = (u_int32_t) ifp->if_unit;
+               ev_msg.dv[0].data_length = sizeof(struct net_event_data);
+               ev_msg.dv[0].data_ptr    = &ev_data;
+               ev_msg.dv[1].data_length = 0;
+               kev_post_msg(&ev_msg);
+
+               ifnet_touch_lastchange(ifp);
+               rt_ifmsg(ifp);
+
                /*
                 * If the link MTU changed, do network layer specific procedure
                 * and update all route entries associated with the interface,
                 * so that their MTU metric gets updated.
                 */
-               if (error == 0 && ifp->if_mtu != oldmtu) {
+               if (ifp->if_mtu != oldmtu) {
                        if_rtmtu_update(ifp);
 #if INET6
                        nd6_setmtu(ifp);
 #endif
                }
-               return (error);
+               break;
        }
 
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                error = proc_suser(p);
-               if (error)
-                       return (error);
+               if (error != 0)
+                       break;
 
                /* Don't allow group membership on non-multicast interfaces. */
-               if ((ifp->if_flags & IFF_MULTICAST) == 0)
-                       return EOPNOTSUPP;
+               if ((ifp->if_flags & IFF_MULTICAST) == 0) {
+                       error = EOPNOTSUPP;
+                       break;
+               }
 
-#ifndef __APPLE__
                /* Don't let users screw up protocols' entries. */
-               if (ifr->ifr_addr.sa_family != AF_LINK)
-                       return EINVAL;
-#endif
+               if (ifr->ifr_addr.sa_family != AF_UNSPEC &&
+                   ifr->ifr_addr.sa_family != AF_LINK) {
+                       error = EINVAL;
+                       break;
+               }
 
+               /*
+                * User is permitted to anonymously join a particular link
+                * multicast group via SIOCADDMULTI.  Subsequent join requested
+                * for the same record which has an outstanding refcnt from a
+                * past if_addmulti_anon() will not result in EADDRINUSE error
+                * (unlike other BSDs.)  Anonymously leaving a group is also
+                * allowed only as long as there is an outstanding refcnt held
+                * by a previous anonymous request, or else ENOENT (even if the
+                * link-layer multicast membership exists for a network-layer
+                * membership.)
+                */
                if (cmd == SIOCADDMULTI) {
-                       error = if_addmulti(ifp, &ifr->ifr_addr, NULL);
+                       error = if_addmulti_anon(ifp, &ifr->ifr_addr, NULL);
                        ev_msg.event_code = KEV_DL_ADDMULTI;
                } else {
-                       error = if_delmulti(ifp, &ifr->ifr_addr);
+                       error = if_delmulti_anon(ifp, &ifr->ifr_addr);
                        ev_msg.event_code = KEV_DL_DELMULTI;
                }
-               if (error == 0) {
-                    ev_msg.vendor_code    = KEV_VENDOR_APPLE;
-                    ev_msg.kev_class      = KEV_NETWORK_CLASS;
-                    ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
-                    strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
-       
-                    ev_data.if_family = ifp->if_family;
-                    ev_data.if_unit   = (u_int32_t) ifp->if_unit;
-                    ev_msg.dv[0].data_length = sizeof(struct net_event_data);
-                    ev_msg.dv[0].data_ptr    = &ev_data;
-                    ev_msg.dv[1].data_length = 0;
-                    kev_post_msg(&ev_msg);
-
-                    ifnet_touch_lastchange(ifp);
-               }
-               return error;
+               if (error != 0)
+                       break;
 
-       case SIOCSIFPHYADDR:
-       case SIOCDIFPHYADDR:
-#if INET6
-       case SIOCSIFPHYADDR_IN6_32:
-       case SIOCSIFPHYADDR_IN6_64:
-#endif
-       case SIOCSLIFPHYADDR:
-       case SIOCSIFMEDIA:
-       case SIOCSIFGENERIC:
-       case SIOCSIFLLADDR:
-       case SIOCSIFALTMTU:
-       case SIOCSIFVLAN:
-       case SIOCSIFBOND:
-               error = proc_suser(p);
-               if (error)
-                       return (error);
+               ev_msg.vendor_code    = KEV_VENDOR_APPLE;
+               ev_msg.kev_class      = KEV_NETWORK_CLASS;
+               ev_msg.kev_subclass   = KEV_DL_SUBCLASS;
+               strlcpy(&ev_data.if_name[0], ifp->if_name, IFNAMSIZ);
+
+               ev_data.if_family = ifp->if_family;
+               ev_data.if_unit   = (u_int32_t) ifp->if_unit;
+               ev_msg.dv[0].data_length = sizeof(struct net_event_data);
+               ev_msg.dv[0].data_ptr    = &ev_data;
+               ev_msg.dv[1].data_length = 0;
+               kev_post_msg(&ev_msg);
+
+               ifnet_touch_lastchange(ifp);
+               break;
+
+       case SIOCSIFPHYADDR:
+       case SIOCDIFPHYADDR:
+#if INET6
+       case SIOCSIFPHYADDR_IN6_32:
+       case SIOCSIFPHYADDR_IN6_64:
+#endif
+       case SIOCSLIFPHYADDR:
+       case SIOCSIFMEDIA:
+       case SIOCSIFGENERIC:
+       case SIOCSIFLLADDR:
+       case SIOCSIFALTMTU:
+       case SIOCSIFVLAN:
+       case SIOCSIFBOND:
+               error = proc_suser(p);
+               if (error != 0)
+                       break;
 
-               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                       cmd, data);
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+               if (error != 0)
+                       break;
 
-               if (error == 0)
-                       ifnet_touch_lastchange(ifp);
-               return error;
+               ifnet_touch_lastchange(ifp);
+               break;
 
        case SIOCGIFSTATUS:
                ifs = (struct ifstat *)data;
                ifs->ascii[0] = '\0';
-               
+
        case SIOCGIFPSRCADDR:
        case SIOCGIFPDSTADDR:
        case SIOCGLIFPHYADDR:
@@ -1447,28 +1746,38 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
        case SIOCGIFMEDIA64:
        case SIOCGIFGENERIC:
        case SIOCGIFDEVMTU:
-               return ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                  cmd, data);
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+               break;
+
        case SIOCGIFVLAN:
        case SIOCGIFBOND:
-               return ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family, 
-                                                  cmd, data);
+               error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
+                   cmd, data);
+               break;
 
        case SIOCGIFWAKEFLAGS:
                ifnet_lock_shared(ifp);
                ifr->ifr_wake_flags = ifnet_get_wake_flags(ifp);
                ifnet_lock_done(ifp);
                break;
-               
+
+       case SIOCGIFGETRTREFCNT:
+               ifnet_lock_shared(ifp);
+               ifr->ifr_route_refcnt = ifp->if_route_refcnt;
+               ifnet_lock_done(ifp);
+               break;
+
        default:
                oif_flags = ifp->if_flags;
-               if (so->so_proto == 0)
-                       return (EOPNOTSUPP);
+               if (so->so_proto == NULL) {
+                       error = EOPNOTSUPP;
+                       break;
+               }
            {
-               int ocmd = cmd;
+               u_long ocmd = cmd;
 
                switch (cmd) {
-
                case SIOCSIFDSTADDR:
                case SIOCSIFADDR:
                case SIOCSIFBRDADDR:
@@ -1500,12 +1809,13 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
                case OSIOCGIFNETMASK:
                        cmd = SIOCGIFNETMASK;
                }
+
                socket_lock(so, 1);
-               error =  ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
-                               data, ifp, p));
+               error = ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd,
+                   data, ifp, p));
                socket_unlock(so, 1);
-               switch (ocmd) {
 
+               switch (ocmd) {
                case OSIOCGIFADDR:
                case OSIOCGIFDSTADDR:
                case OSIOCGIFBRDADDR:
@@ -1521,12 +1831,12 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
                }
 
                if (error == EOPNOTSUPP || error == ENOTSUP)
-                       error = ifnet_ioctl(ifp, so->so_proto->pr_domain->dom_family,
-                                                               cmd, data);
+                       error = ifnet_ioctl(ifp,
+                           so->so_proto->pr_domain->dom_family, cmd, data);
 
-               return (error);
+               break;
        }
-       return (0);
+       return (error);
 }
 
 int
@@ -1551,47 +1861,43 @@ ifnet_set_promiscuous(
        ifnet_t ifp,
        int pswitch)
 {
-       struct ifreq ifr;
        int error = 0;
-       int oldflags;
-       int locked = 0;
-       int changed = 0;
+       int oldflags = 0;
+       int newflags = 0;
 
        ifnet_lock_exclusive(ifp);
-       locked = 1;
        oldflags = ifp->if_flags;
-       if (pswitch) {
-               /*
-                * If the device is not configured up, we cannot put it in
-                * promiscuous mode.
-                */
-               if ((ifp->if_flags & IFF_UP) == 0) {
-                       error = ENETDOWN;
-                       goto done;
-               }
-               if (ifp->if_pcount++ != 0) {
-                       goto done;
-               }
+       ifp->if_pcount += pswitch ? 1 : -1;
+       
+       if (ifp->if_pcount > 0)
                ifp->if_flags |= IFF_PROMISC;
-       } else {
-               if (--ifp->if_pcount > 0)
-                       goto done;
+       else
                ifp->if_flags &= ~IFF_PROMISC;
-       }
-       ifr.ifr_flags = ifp->if_flags;
-       locked = 0;
+       
+       newflags = ifp->if_flags;
        ifnet_lock_done(ifp);
-       error = ifnet_ioctl(ifp, 0, SIOCSIFFLAGS, &ifr);
-       if (error == 0)
-               rt_ifmsg(ifp);
-       else
-               ifp->if_flags = oldflags;
-done:
-       if (locked) ifnet_lock_done(ifp);
-       if (changed) {
-               log(LOG_INFO, "%s%d: promiscuous mode %s\n",
+       
+       if (newflags != oldflags && (newflags & IFF_UP) != 0) {
+               error = ifnet_ioctl(ifp, 0, SIOCSIFFLAGS, NULL);
+               if (error == 0) {
+                       rt_ifmsg(ifp);
+               } else {
+                       ifnet_lock_exclusive(ifp);
+                       // revert the flags
+                       ifp->if_pcount -= pswitch ? 1 : -1;
+                       if (ifp->if_pcount > 0)
+                           ifp->if_flags |= IFF_PROMISC;
+                       else
+                           ifp->if_flags &= ~IFF_PROMISC;
+                       ifnet_lock_done(ifp);
+               }
+       }
+       
+       if (newflags != oldflags) {
+               log(LOG_INFO, "%s%d: promiscuous mode %s%s\n",
                    ifp->if_name, ifp->if_unit,
-                   pswitch != 0 ? "enabled" : "disabled");
+                   (newflags & IFF_PROMISC) != 0 ? "enable" : "disable",
+                   error != 0 ? " failed" : " succeeded");
        }
        return error;
 }
@@ -1611,7 +1917,7 @@ ifconf(u_long cmd, user_addr_t ifrp, int * ret_space)
        struct ifreq ifr;
        int error = 0;
        size_t space;
-       
+
        /*
         * Zero the ifr buffer to make sure we don't
         * disclose the contents of the stack.
@@ -1620,7 +1926,8 @@ ifconf(u_long cmd, user_addr_t ifrp, int * ret_space)
 
        space = *ret_space;
        ifnet_head_lock_shared();
-       for (ifp = ifnet_head.tqh_first; space > sizeof(ifr) && ifp; ifp = ifp->if_link.tqe_next) {
+       for (ifp = ifnet_head.tqh_first; space > sizeof(ifr) &&
+           ifp; ifp = ifp->if_link.tqe_next) {
                char workbuf[64];
                size_t ifnlen, addrs;
 
@@ -1632,17 +1939,22 @@ ifconf(u_long cmd, user_addr_t ifrp, int * ret_space)
                } else {
                        strlcpy(ifr.ifr_name, workbuf, IFNAMSIZ);
                }
-               
+
                ifnet_lock_shared(ifp);
 
                addrs = 0;
                ifa = ifp->if_addrhead.tqh_first;
                for ( ; space > sizeof (ifr) && ifa;
                    ifa = ifa->ifa_link.tqe_next) {
-                       struct sockaddr *sa = ifa->ifa_addr;
+                       struct sockaddr *sa;
+
+                       IFA_LOCK(ifa);
+                       sa = ifa->ifa_addr;
 #ifndef __APPLE__
-                       if (curproc->p_prison && prison_if(curproc, sa))
+                       if (curproc->p_prison && prison_if(curproc, sa)) {
+                               IFA_UNLOCK(ifa);
                                continue;
+                       }
 #endif
                        addrs++;
                        if (cmd == OSIOCGIFCONF32 || cmd == OSIOCGIFCONF64) {
@@ -1650,30 +1962,38 @@ ifconf(u_long cmd, user_addr_t ifrp, int * ret_space)
                                         (struct osockaddr *)&ifr.ifr_addr;
                                ifr.ifr_addr = *sa;
                                osa->sa_family = sa->sa_family;
-                               error = copyout((caddr_t)&ifr, ifrp, sizeof(ifr));
+                               error = copyout((caddr_t)&ifr, ifrp,
+                                   sizeof (ifr));
                                ifrp += sizeof(struct ifreq);
                        } else if (sa->sa_len <= sizeof(*sa)) {
                                ifr.ifr_addr = *sa;
-                               error = copyout((caddr_t)&ifr, ifrp, sizeof(ifr));
+                               error = copyout((caddr_t)&ifr, ifrp,
+                                   sizeof (ifr));
                                ifrp += sizeof(struct ifreq);
                        } else {
-                               if (space < sizeof (ifr) + sa->sa_len - sizeof(*sa))
+                               if (space <
+                                   sizeof (ifr) + sa->sa_len - sizeof(*sa)) {
+                                       IFA_UNLOCK(ifa);
                                        break;
+                               }
                                space -= sa->sa_len - sizeof(*sa);
-                               error = copyout((caddr_t)&ifr, ifrp, sizeof (ifr.ifr_name));
+                               error = copyout((caddr_t)&ifr, ifrp,
+                                   sizeof (ifr.ifr_name));
                                if (error == 0) {
-                                   error = copyout((caddr_t)sa,
-                                               (ifrp + offsetof(struct ifreq, ifr_addr)),
-                                               sa->sa_len);
+                                   error = copyout((caddr_t)sa, (ifrp +
+                                       offsetof(struct ifreq, ifr_addr)),
+                                       sa->sa_len);
                                }
-                               ifrp += (sa->sa_len + offsetof(struct ifreq, ifr_addr));
+                               ifrp += (sa->sa_len + offsetof(struct ifreq,
+                                   ifr_addr));
                        }
+                       IFA_UNLOCK(ifa);
                        if (error)
                                break;
                        space -= sizeof (ifr);
                }
                ifnet_lock_done(ifp);
-               
+
                if (error)
                        break;
                if (!addrs) {
@@ -1725,64 +2045,300 @@ if_allmulti(struct ifnet *ifp, int onswitch)
        return error;
 }
 
+static struct ifmultiaddr *
+ifma_alloc(int how)
+{
+       struct ifmultiaddr *ifma;
+
+       ifma = (how == M_WAITOK) ? zalloc(ifma_zone) :
+           zalloc_noblock(ifma_zone);
+
+       if (ifma != NULL) {
+               bzero(ifma, ifma_size);
+               lck_mtx_init(&ifma->ifma_lock, ifa_mtx_grp, ifa_mtx_attr);
+               ifma->ifma_debug |= IFD_ALLOC;
+               if (ifma_debug != 0) {
+                       ifma->ifma_debug |= IFD_DEBUG;
+                       ifma->ifma_trace = ifma_trace;
+               }
+       }
+       return (ifma);
+}
+
+static void
+ifma_free(struct ifmultiaddr *ifma)
+{
+       IFMA_LOCK(ifma);
+
+       if (ifma->ifma_protospec != NULL) {
+               panic("%s: Protospec not NULL for ifma=%p", __func__, ifma);
+               /* NOTREACHED */
+       } else if ((ifma->ifma_flags & IFMAF_ANONYMOUS) ||
+           ifma->ifma_anoncnt != 0) {
+               panic("%s: Freeing ifma=%p with outstanding anon req",
+                   __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_debug & IFD_ATTACHED) {
+               panic("%s: ifma=%p attached to ifma_ifp=%p is being freed",
+                   __func__, ifma, ifma->ifma_ifp);
+               /* NOTREACHED */
+       } else if (!(ifma->ifma_debug & IFD_ALLOC)) {
+               panic("%s: ifma %p cannot be freed", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_refcount != 0) {
+               panic("%s: non-zero refcount ifma=%p", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_reqcnt != 0) {
+               panic("%s: non-zero reqcnt ifma=%p", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_ifp != NULL) {
+               panic("%s: non-NULL ifma_ifp=%p for ifma=%p", __func__,
+                   ifma->ifma_ifp, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_ll != NULL) {
+               panic("%s: non-NULL ifma_ll=%p for ifma=%p", __func__,
+                   ifma->ifma_ll, ifma);
+               /* NOTREACHED */
+       }
+       ifma->ifma_debug &= ~IFD_ALLOC;
+       if ((ifma->ifma_debug & (IFD_DEBUG | IFD_TRASHED)) ==
+           (IFD_DEBUG | IFD_TRASHED)) {
+               lck_mtx_lock(&ifma_trash_lock);
+               TAILQ_REMOVE(&ifma_trash_head, (struct ifmultiaddr_dbg *)ifma,
+                   ifma_trash_link);
+               lck_mtx_unlock(&ifma_trash_lock);
+               ifma->ifma_debug &= ~IFD_TRASHED;
+       }
+       IFMA_UNLOCK(ifma);
+
+       if (ifma->ifma_addr != NULL) {
+               FREE(ifma->ifma_addr, M_IFADDR);
+               ifma->ifma_addr = NULL;
+       }
+       lck_mtx_destroy(&ifma->ifma_lock, ifa_mtx_grp);
+       zfree(ifma_zone, ifma);
+}
+
+static void
+ifma_trace(struct ifmultiaddr *ifma, int refhold)
+{
+       struct ifmultiaddr_dbg *ifma_dbg = (struct ifmultiaddr_dbg *)ifma;
+       ctrace_t *tr;
+       u_int32_t idx;
+       u_int16_t *cnt;
+
+       if (!(ifma->ifma_debug & IFD_DEBUG)) {
+               panic("%s: ifma %p has no debug structure", __func__, ifma);
+               /* NOTREACHED */
+       }
+       if (refhold) {
+               cnt = &ifma_dbg->ifma_refhold_cnt;
+               tr = ifma_dbg->ifma_refhold;
+       } else {
+               cnt = &ifma_dbg->ifma_refrele_cnt;
+               tr = ifma_dbg->ifma_refrele;
+       }
+
+       idx = atomic_add_16_ov(cnt, 1) % IFMA_TRACE_HIST_SIZE;
+       ctrace_record(&tr[idx]);
+}
+
 void
-ifma_reference(
-       struct ifmultiaddr *ifma)
+ifma_addref(struct ifmultiaddr *ifma, int locked)
 {
-       if (OSIncrementAtomic(&ifma->ifma_refcount) <= 0)
-               panic("ifma_reference: ifma already released or invalid\n");
+       if (!locked)
+               IFMA_LOCK(ifma);
+       else
+               IFMA_LOCK_ASSERT_HELD(ifma);
+
+       if (++ifma->ifma_refcount == 0) {
+               panic("%s: ifma=%p wraparound refcnt", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_trace != NULL) {
+               (*ifma->ifma_trace)(ifma, TRUE);
+       }
+       if (!locked)
+               IFMA_UNLOCK(ifma);
 }
 
 void
-ifma_release(
-       struct ifmultiaddr *ifma)
-{
-       while (ifma) {
-               struct ifmultiaddr *next;
-               int32_t prevValue = OSDecrementAtomic(&ifma->ifma_refcount);
-               if (prevValue < 1)
-                       panic("ifma_release: ifma already released or invalid\n");
-               if (prevValue != 1)
-                       break;
-               
-               /* Allow the allocator of the protospec to free it */
-               if (ifma->ifma_protospec && ifma->ifma_free) {
-                       ifma->ifma_free(ifma->ifma_protospec);
-               }
-               
-               next = ifma->ifma_ll;
-               FREE(ifma->ifma_addr, M_IFMADDR);
-               FREE(ifma, M_IFMADDR);
-               ifma = next;
+ifma_remref(struct ifmultiaddr *ifma)
+{
+       struct ifmultiaddr *ll;
+
+       IFMA_LOCK(ifma);
+
+       if (ifma->ifma_refcount == 0) {
+               panic("%s: ifma=%p negative refcnt", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_trace != NULL) {
+               (*ifma->ifma_trace)(ifma, FALSE);
+       }
+
+       --ifma->ifma_refcount;
+       if (ifma->ifma_refcount > 0) {
+               IFMA_UNLOCK(ifma);
+               return;
+       }
+
+       ll = ifma->ifma_ll;
+       ifma->ifma_ifp = NULL;
+       ifma->ifma_ll = NULL;
+       IFMA_UNLOCK(ifma);
+       ifma_free(ifma);        /* deallocate it */
+
+       if (ll != NULL)
+               IFMA_REMREF(ll);
+}
+
+static void
+if_attach_ifma(struct ifnet *ifp, struct ifmultiaddr *ifma, int anon)
+{
+       ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
+       IFMA_LOCK_ASSERT_HELD(ifma);
+
+       if (ifma->ifma_ifp != ifp) {
+               panic("%s: Mismatch ifma_ifp=%p != ifp=%p", __func__,
+                   ifma->ifma_ifp, ifp);
+               /* NOTREACHED */
+       } else if (ifma->ifma_debug & IFD_ATTACHED) {
+               panic("%s: Attempt to attach an already attached ifma=%p",
+                   __func__, ifma);
+               /* NOTREACHED */
+       } else if (anon && (ifma->ifma_flags & IFMAF_ANONYMOUS)) {
+               panic("%s: ifma=%p unexpected IFMAF_ANONYMOUS", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_debug & IFD_TRASHED) {
+               panic("%s: Attempt to reattach a detached ifma=%p",
+                   __func__, ifma);
+               /* NOTREACHED */
+       }
+
+       ifma->ifma_reqcnt++;
+       VERIFY(ifma->ifma_reqcnt == 1);
+       IFMA_ADDREF_LOCKED(ifma);
+       ifma->ifma_debug |= IFD_ATTACHED;
+       if (anon) {
+               ifma->ifma_anoncnt++;
+               VERIFY(ifma->ifma_anoncnt == 1);
+               ifma->ifma_flags |= IFMAF_ANONYMOUS;
        }
+
+       LIST_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
 }
 
- /*
-  * Find an ifmultiaddr that matches a socket address on an interface. 
-  *
-  * Caller is responsible for holding the ifnet_lock while calling
-  * this function.
-  */
 static int
-if_addmulti_doesexist(
-       struct ifnet *ifp,
-       const struct sockaddr *sa,
-       struct ifmultiaddr **retifma)
+if_detach_ifma(struct ifnet *ifp, struct ifmultiaddr *ifma, int anon)
+{
+       ifnet_lock_assert(ifp, IFNET_LCK_ASSERT_EXCLUSIVE);
+       IFMA_LOCK_ASSERT_HELD(ifma);
+
+       if (ifma->ifma_reqcnt == 0) {
+               panic("%s: ifma=%p negative reqcnt", __func__, ifma);
+               /* NOTREACHED */
+       } else if (anon && !(ifma->ifma_flags & IFMAF_ANONYMOUS)) {
+               panic("%s: ifma=%p missing IFMAF_ANONYMOUS", __func__, ifma);
+               /* NOTREACHED */
+       } else if (anon && ifma->ifma_anoncnt == 0) {
+               panic("%s: ifma=%p negative anonreqcnt", __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_ifp != ifp) {
+               panic("%s: Mismatch ifma_ifp=%p, ifp=%p", __func__,
+                   ifma->ifma_ifp, ifp);
+               /* NOTREACHED */
+       }
+
+       if (anon) {
+               --ifma->ifma_anoncnt;
+               if (ifma->ifma_anoncnt > 0)
+                       return (0);
+               ifma->ifma_flags &= ~IFMAF_ANONYMOUS;
+       }
+
+       --ifma->ifma_reqcnt;
+       if (ifma->ifma_reqcnt > 0)
+               return (0);
+
+       if (ifma->ifma_protospec != NULL) {
+               panic("%s: Protospec not NULL for ifma=%p", __func__, ifma);
+               /* NOTREACHED */
+       } else if ((ifma->ifma_flags & IFMAF_ANONYMOUS) ||
+           ifma->ifma_anoncnt != 0) {
+               panic("%s: Detaching ifma=%p with outstanding anon req",
+                   __func__, ifma);
+               /* NOTREACHED */
+       } else if (!(ifma->ifma_debug & IFD_ATTACHED)) {
+               panic("%s: Attempt to detach an unattached address ifma=%p",
+                   __func__, ifma);
+               /* NOTREACHED */
+       } else if (ifma->ifma_debug & IFD_TRASHED) {
+               panic("%s: ifma %p is already in trash list", __func__, ifma);
+               /* NOTREACHED */
+       }
+
+       /*
+        * NOTE: Caller calls IFMA_REMREF
+        */
+       ifma->ifma_debug &= ~IFD_ATTACHED;
+       LIST_REMOVE(ifma, ifma_link);
+       if (LIST_EMPTY(&ifp->if_multiaddrs))
+               ifp->if_updatemcasts = 0;
+
+       if (ifma->ifma_debug & IFD_DEBUG) {
+               /* Become a regular mutex, just in case */
+               IFMA_CONVERT_LOCK(ifma);
+               lck_mtx_lock(&ifma_trash_lock);
+               TAILQ_INSERT_TAIL(&ifma_trash_head,
+                   (struct ifmultiaddr_dbg *)ifma, ifma_trash_link);
+               lck_mtx_unlock(&ifma_trash_lock);
+               ifma->ifma_debug |= IFD_TRASHED;
+       }
+
+       return (1);
+}
+
+/*
+ * Find an ifmultiaddr that matches a socket address on an interface. 
+ *
+ * Caller is responsible for holding the ifnet_lock while calling
+ * this function.
+ */
+static int
+if_addmulti_doesexist(struct ifnet *ifp, const struct sockaddr *sa,
+    struct ifmultiaddr **retifma, int anon)
 {
        struct ifmultiaddr *ifma;
-       for (ifma = ifp->if_multiaddrs.lh_first; ifma;
-            ifma = ifma->ifma_link.le_next) {
-               if (equal(sa, ifma->ifma_addr)) {
-                       ifma->ifma_usecount++;
-                       if (retifma) {
-                               *retifma = ifma;
-                               ifma_reference(*retifma);
+
+       for (ifma = LIST_FIRST(&ifp->if_multiaddrs); ifma != NULL;
+            ifma = LIST_NEXT(ifma, ifma_link)) {
+               IFMA_LOCK_SPIN(ifma);
+               if (!equal(sa, ifma->ifma_addr)) {
+                       IFMA_UNLOCK(ifma);
+                       continue;
+               }
+               if (anon) {
+                       VERIFY(!(ifma->ifma_flags & IFMAF_ANONYMOUS) ||
+                           ifma->ifma_anoncnt != 0);
+                       VERIFY((ifma->ifma_flags & IFMAF_ANONYMOUS) ||
+                           ifma->ifma_anoncnt == 0);
+                       ifma->ifma_anoncnt++;
+                       if (!(ifma->ifma_flags & IFMAF_ANONYMOUS)) {
+                               VERIFY(ifma->ifma_anoncnt == 1);
+                               ifma->ifma_flags |= IFMAF_ANONYMOUS;
                        }
-                       return 0;
                }
+               if (!anon || ifma->ifma_anoncnt == 1) {
+                       ifma->ifma_reqcnt++;
+                       VERIFY(ifma->ifma_reqcnt > 1);
+               }
+               if (retifma != NULL) {
+                       *retifma = ifma;
+                       IFMA_ADDREF_LOCKED(ifma);
+               }
+               IFMA_UNLOCK(ifma);
+               return (0);
        }
-       
-       return ENOENT;
+       return (ENOENT);
 }
 
 /*
@@ -1851,67 +2407,114 @@ copy_and_normalize(
 }
 
 /*
- * Add a multicast listenership to the interface in question.
- * The link layer provides a routine which converts
+ * Network-layer protocol domains which hold references to the underlying
+ * link-layer record must use this routine.
+ */
+int
+if_addmulti(struct ifnet *ifp, const struct sockaddr *sa,
+    struct ifmultiaddr **retifma)
+{
+       return (if_addmulti_common(ifp, sa, retifma, 0));
+}
+
+/*
+ * Anything other than network-layer protocol domains which hold references
+ * to the underlying link-layer record must use this routine: SIOCADDMULTI
+ * ioctl, ifnet_add_multicast(), AppleTalk, if_bond.
  */
 int
-if_addmulti(
-       struct ifnet *ifp,      /* interface to manipulate */
-       const struct sockaddr *sa,      /* address to add */
-       struct ifmultiaddr **retifma)
+if_addmulti_anon(struct ifnet *ifp, const struct sockaddr *sa,
+    struct ifmultiaddr **retifma)
+{
+       return (if_addmulti_common(ifp, sa, retifma, 1));
+}
+
+/*
+ * Register an additional multicast address with a network interface.
+ *
+ * - If the address is already present, bump the reference count on the
+ *   address and return.
+ * - If the address is not link-layer, look up a link layer address.
+ * - Allocate address structures for one or both addresses, and attach to the
+ *   multicast address list on the interface.  If automatically adding a link
+ *   layer address, the protocol address will own a reference to the link
+ *   layer address, to be freed when it is freed.
+ * - Notify the network device driver of an addition to the multicast address
+ *   list.
+ *
+ * 'sa' points to caller-owned memory with the desired multicast address.
+ *
+ * 'retifma' will be used to return a pointer to the resulting multicast
+ * address reference, if desired.
+ *
+ * 'anon' indicates a link-layer address with no protocol address reference
+ * made to it.  Anything other than network-layer protocol domain requests
+ * are considered as anonymous.
+ */
+static int
+if_addmulti_common(struct ifnet *ifp, const struct sockaddr *sa,
+    struct ifmultiaddr **retifma, int anon)
 {
        struct sockaddr_storage storage;
        struct sockaddr *llsa = NULL;
        struct sockaddr *dupsa = NULL;
-       int error = 0;
+       int error = 0, ll_firstref = 0, lladdr;
        struct ifmultiaddr *ifma = NULL;
        struct ifmultiaddr *llifma = NULL;
-       
+
+       /* Only AF_UNSPEC/AF_LINK is allowed for an "anonymous" address */
+       VERIFY(!anon || sa->sa_family == AF_UNSPEC ||
+           sa->sa_family == AF_LINK);
+
        /* If sa is a AF_LINK or AF_UNSPEC, duplicate and normalize it */
        if (sa->sa_family == AF_LINK || sa->sa_family == AF_UNSPEC) {
                dupsa = copy_and_normalize(sa);
                if (dupsa == NULL) {
-                       return ENOMEM;
+                       error = ENOMEM;
+                       goto cleanup;
                }
                sa = dupsa;
        }
-       
+
        ifnet_lock_exclusive(ifp);
-       error = if_addmulti_doesexist(ifp, sa, retifma);
-       ifnet_lock_done(ifp);
-       
-       if (error == 0) {
+       if (!(ifp->if_flags & IFF_MULTICAST)) {
+               error = EADDRNOTAVAIL;
+               ifnet_lock_done(ifp);
                goto cleanup;
        }
 
+       /* If the address is already present, return a new reference to it */
+       error = if_addmulti_doesexist(ifp, sa, retifma, anon);
+       ifnet_lock_done(ifp);
+       if (error == 0)
+               goto cleanup;
+
        /*
-        * Give the link layer a chance to accept/reject it, and also
-        * find out which AF_LINK address this maps to, if it isn't one
-        * already.
+        * The address isn't already present; give the link layer a chance
+        * to accept/reject it, and also find out which AF_LINK address this
+        * maps to, if it isn't one already.
         */
-       error = dlil_resolve_multi(ifp, sa, (struct sockaddr*)&storage,
-                                                          sizeof(storage));
+       error = dlil_resolve_multi(ifp, sa, (struct sockaddr *)&storage,
+           sizeof (storage));
        if (error == 0 && storage.ss_len != 0) {
-               llsa = copy_and_normalize((struct sockaddr*)&storage);
+               llsa = copy_and_normalize((struct sockaddr *)&storage);
                if (llsa == NULL) {
                        error = ENOMEM;
                        goto cleanup;
                }
-               
-               MALLOC(llifma, struct ifmultiaddr *, sizeof *llifma, M_IFMADDR, M_WAITOK);
+
+               llifma = ifma_alloc(M_WAITOK);
                if (llifma == NULL) {
                        error = ENOMEM;
                        goto cleanup;
                }
        }
-       
+
        /* to be similar to FreeBSD */
-       if (error == EOPNOTSUPP) {
+       if (error == EOPNOTSUPP)
                error = 0;
-       }
-       else if (error) {
+       else if (error != 0)
                goto cleanup;
-       }
 
        /* Allocate while we aren't holding any locks */
        if (dupsa == NULL) {
@@ -1921,185 +2524,212 @@ if_addmulti(
                        goto cleanup;
                }
        }
-       MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma, M_IFMADDR, M_WAITOK);
+       ifma = ifma_alloc(M_WAITOK);
        if (ifma == NULL) {
                error = ENOMEM;
                goto cleanup;
        }
-       
+
        ifnet_lock_exclusive(ifp);
        /*
         * Check again for the matching multicast.
         */
-       if ((error = if_addmulti_doesexist(ifp, sa, retifma)) == 0) {
+       error = if_addmulti_doesexist(ifp, sa, retifma, anon);
+       if (error == 0) {
                ifnet_lock_done(ifp);
                goto cleanup;
        }
 
-       bzero(ifma, sizeof(*ifma));
-       ifma->ifma_addr = dupsa;
-       ifma->ifma_ifp = ifp;
-       ifma->ifma_usecount = 1;
-       ifma->ifma_refcount = 1;
-       
-       if (llifma != 0) {
-               if (if_addmulti_doesexist(ifp, llsa, &ifma->ifma_ll) == 0) {
-                       FREE(llsa, M_IFMADDR);
-                       FREE(llifma, M_IFMADDR);
+       if (llifma != NULL) {
+               VERIFY(!anon);  /* must not get here if "anonymous" */
+               if (if_addmulti_doesexist(ifp, llsa, &ifma->ifma_ll, 0) == 0) {
+                       FREE(llsa, M_IFADDR);
+                       llsa = NULL;
+                       ifma_free(llifma);
+                       llifma = NULL;
+                       VERIFY(ifma->ifma_ll->ifma_ifp == ifp);
                } else {
-                       bzero(llifma, sizeof(*llifma));
+                       ll_firstref = 1;
                        llifma->ifma_addr = llsa;
                        llifma->ifma_ifp = ifp;
-                       llifma->ifma_usecount = 1;
-                       llifma->ifma_refcount = 1;
-                       LIST_INSERT_HEAD(&ifp->if_multiaddrs, llifma, ifma_link);
-
+                       IFMA_LOCK(llifma);
+                       if_attach_ifma(ifp, llifma, 0);
+                       /* add extra refcnt for ifma */
+                       IFMA_ADDREF_LOCKED(llifma);
+                       IFMA_UNLOCK(llifma);
                        ifma->ifma_ll = llifma;
-                       ifma_reference(ifma->ifma_ll);
                }
        }
-       
-       LIST_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
-       
-       if (retifma) {
+
+       /* "anonymous" request should not result in network address */
+       VERIFY(!anon || ifma->ifma_ll == NULL);
+
+       ifma->ifma_addr = dupsa;
+       ifma->ifma_ifp = ifp;
+       IFMA_LOCK(ifma);
+       if_attach_ifma(ifp, ifma, anon);
+       IFMA_ADDREF_LOCKED(ifma);               /* for this routine */
+       if (retifma != NULL) {
                *retifma = ifma;
-               ifma_reference(*retifma);
+               IFMA_ADDREF_LOCKED(*retifma);   /* for caller */
        }
-
+       lladdr = (ifma->ifma_addr->sa_family == AF_UNSPEC ||
+           ifma->ifma_addr->sa_family == AF_LINK);
+       IFMA_UNLOCK(ifma);
        ifnet_lock_done(ifp);
-       
-       if (llsa != 0)
-               rt_newmaddrmsg(RTM_NEWMADDR, ifma);
+
+       rt_newmaddrmsg(RTM_NEWMADDR, ifma);
+       IFMA_REMREF(ifma);                      /* for this routine */
 
        /*
         * We are certain we have added something, so call down to the
-        * interface to let them know about it.
+        * interface to let them know about it.  Do this only for newly-
+        * added AF_LINK/AF_UNSPEC address in the if_multiaddrs set.
         */
-       ifnet_ioctl(ifp, 0, SIOCADDMULTI, NULL);
-       
-       return 0;
-       
+       if (lladdr || ll_firstref)
+               (void) ifnet_ioctl(ifp, 0, SIOCADDMULTI, NULL);
+
+       if (ifp->if_updatemcasts > 0)
+               ifp->if_updatemcasts = 0;
+
+       return (0);
+
 cleanup:
-       if (ifma)
-               FREE(ifma, M_IFADDR);
-       if (dupsa)
+       if (ifma != NULL)
+               ifma_free(ifma);
+       if (dupsa != NULL)
                FREE(dupsa, M_IFADDR);
-       if (llifma)
-               FREE(llifma, M_IFADDR);
-       if (llsa)
+       if (llifma != NULL)
+               ifma_free(llifma);
+       if (llsa != NULL)
                FREE(llsa, M_IFADDR);
-       
-       return error;
+
+       return (error);
 }
 
+/*
+ * Delete a multicast group membership by network-layer group address.
+ * This routine is deprecated.
+ */
 int
-if_delmultiaddr(
-       struct ifmultiaddr *ifma,
-       int locked)
+if_delmulti(struct ifnet *ifp, const struct sockaddr *sa)
 {
-       struct ifnet *ifp;
-       int     do_del_multi = 0;
-       
-       ifp = ifma->ifma_ifp;
-       
-       if (!locked && ifp) {
-               ifnet_lock_exclusive(ifp);
-       }
-       
-       while (ifma != NULL) {
-               struct ifmultiaddr *ll_ifma;
-               
-               if (ifma->ifma_usecount > 1) {
-                       ifma->ifma_usecount--;
-                       break;
-               }
-               
-               if (ifp)
-                       LIST_REMOVE(ifma, ifma_link);
-       
-               ll_ifma = ifma->ifma_ll;
-       
-               if (ll_ifma) { /* send a routing msg for network addresses only */
-                       if (ifp)
-                               ifnet_lock_done(ifp);
-                       rt_newmaddrmsg(RTM_DELMADDR, ifma);
-                       if (ifp)
-                               ifnet_lock_exclusive(ifp);
-               }
-               
-               /*
-                * Make sure the interface driver is notified
-                * in the case of a link layer mcast group being left.
-                */
-               if (ll_ifma == 0) {
-                       if (ifp && ifma->ifma_addr->sa_family == AF_LINK)
-                               do_del_multi = 1;
-                       break;
-               }
-               
-               if (ifp)
-                       ifma_release(ifma);
-       
-               ifma = ll_ifma;
-       }
-       
-       if (!locked && ifp) {
-               /* This wasn't initially locked, we should unlock it */
-               ifnet_lock_done(ifp);
-       }
-       
-       if (do_del_multi) {
-               if (locked)
-                       ifnet_lock_done(ifp);
-               ifnet_ioctl(ifp, 0, SIOCDELMULTI, NULL);
-               if (locked)
-                       ifnet_lock_exclusive(ifp);
-       }
-       
-       return 0;
+       return (if_delmulti_common(NULL, ifp, sa, 0));
+}
+
+/*
+ * Delete a multicast group membership by group membership pointer.
+ * Network-layer protocol domains must use this routine.
+ */
+int
+if_delmulti_ifma(struct ifmultiaddr *ifma)
+{
+       return (if_delmulti_common(ifma, NULL, NULL, 0));
 }
 
 /*
- * Remove a reference to a multicast address on this interface.  Yell
- * if the request does not match an existing membership.
+ * Anything other than network-layer protocol domains which hold references
+ * to the underlying link-layer record must use this routine: SIOCDELMULTI
+ * ioctl, ifnet_remove_multicast(), AppleTalk, if_bond.
  */
 int
-if_delmulti(
-       struct ifnet *ifp,
-       const struct sockaddr *sa)
+if_delmulti_anon(struct ifnet *ifp, const struct sockaddr *sa)
+{
+       return (if_delmulti_common(NULL, ifp, sa, 1));
+}
+
+/*
+ * Delete a multicast group membership by network-layer group address.
+ *
+ * Returns ENOENT if the entry could not be found.
+ */
+static int
+if_delmulti_common(struct ifmultiaddr *ifma, struct ifnet *ifp,
+    const struct sockaddr *sa, int anon)
 {
-       struct ifmultiaddr      *ifma;
        struct sockaddr         *dupsa = NULL;
-       int retval = 0;
+       int                     lastref, ll_lastref = 0, lladdr;
+       struct ifmultiaddr      *ll = NULL;
 
-       if (sa->sa_family == AF_LINK || sa->sa_family == AF_UNSPEC) {
+       /* sanity check for callers */
+       VERIFY(ifma != NULL || (ifp != NULL && sa != NULL));
+
+       if (ifma != NULL)
+               ifp = ifma->ifma_ifp;
+
+       if (sa != NULL &&
+           (sa->sa_family == AF_LINK || sa->sa_family == AF_UNSPEC)) {
                dupsa = copy_and_normalize(sa);
-               if (dupsa == NULL) {
-                       return ENOMEM;
-               }
+               if (dupsa == NULL)
+                       return (ENOMEM);
                sa = dupsa;
        }
-       
+
        ifnet_lock_exclusive(ifp);
-       for (ifma = ifp->if_multiaddrs.lh_first; ifma;
-            ifma = ifma->ifma_link.le_next)
-               if (equal(sa, ifma->ifma_addr))
+       if (ifma == NULL) {
+               for (ifma = LIST_FIRST(&ifp->if_multiaddrs); ifma != NULL;
+                    ifma = LIST_NEXT(ifma, ifma_link)) {
+                       IFMA_LOCK(ifma);
+                       if (!equal(sa, ifma->ifma_addr) ||
+                           (anon && !(ifma->ifma_flags & IFMAF_ANONYMOUS))) {
+                               VERIFY(!(ifma->ifma_flags & IFMAF_ANONYMOUS) ||
+                                   ifma->ifma_anoncnt != 0);
+                               IFMA_UNLOCK(ifma);
+                               continue;
+                       }
+                       /* found; keep it locked */
                        break;
-       if (ifma == 0) {
-               ifnet_lock_done(ifp);
-               if (dupsa)
-                       FREE(dupsa, M_IFADDR);
-               return ENOENT;
+               }
+               if (ifma == NULL) {
+                       if (dupsa != NULL)
+                               FREE(dupsa, M_IFADDR);
+                       ifnet_lock_done(ifp);
+                       return (ENOENT);
+               }
+       } else {
+               IFMA_LOCK(ifma);
+       }
+       IFMA_LOCK_ASSERT_HELD(ifma);
+       IFMA_ADDREF_LOCKED(ifma);       /* for this routine */
+       lastref = if_detach_ifma(ifp, ifma, anon);
+       VERIFY(!lastref || (!(ifma->ifma_debug & IFD_ATTACHED) &&
+           ifma->ifma_reqcnt == 0));
+       VERIFY(!anon || ifma->ifma_ll == NULL);
+       ll = ifma->ifma_ll;
+       lladdr = (ifma->ifma_addr->sa_family == AF_UNSPEC ||
+           ifma->ifma_addr->sa_family == AF_LINK);
+       IFMA_UNLOCK(ifma);
+       if (lastref && ll != NULL) {
+               IFMA_LOCK(ll);
+               ll_lastref = if_detach_ifma(ifp, ll, 0);
+               IFMA_UNLOCK(ll);
        }
-       
-       retval = if_delmultiaddr(ifma, 1);
        ifnet_lock_done(ifp);
-       if (dupsa)
+
+       if (lastref)
+               rt_newmaddrmsg(RTM_DELMADDR, ifma);
+
+       if ((ll == NULL && lastref && lladdr) || ll_lastref) {
+               /*
+                * Make sure the interface driver is notified in the
+                * case of a link layer mcast group being left.  Do
+                * this only for a AF_LINK/AF_UNSPEC address that has
+                * been removed from the if_multiaddrs set.
+                */
+               ifnet_ioctl(ifp, 0, SIOCDELMULTI, NULL);
+       }
+
+       if (lastref)
+               IFMA_REMREF(ifma);      /* for if_multiaddrs list */
+       if (ll_lastref)
+               IFMA_REMREF(ll);        /* for if_multiaddrs list */
+
+       IFMA_REMREF(ifma);              /* for this routine */
+       if (dupsa != NULL)
                FREE(dupsa, M_IFADDR);
-       
-       return retval;
-}
 
+       return (0);
+}
 
 /*
  * We don't use if_setlladdr, our interfaces are responsible for
@@ -2113,21 +2743,6 @@ if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
 }
 #endif
 
-struct ifmultiaddr *
-ifmaof_ifpforaddr(const struct sockaddr *sa, struct ifnet *ifp)
-{
-       struct ifmultiaddr *ifma;
-       
-       ifnet_lock_shared(ifp);
-       for (ifma = ifp->if_multiaddrs.lh_first; ifma;
-            ifma = ifma->ifma_link.le_next)
-               if (equal(ifma->ifma_addr, sa))
-                       break;
-       ifnet_lock_done(ifp);
-
-       return ifma;
-}
-
 SYSCTL_NODE(_net, PF_LINK, link, CTLFLAG_RW|CTLFLAG_LOCKED, 0, "Link layers");
 SYSCTL_NODE(_net_link, 0, generic, CTLFLAG_RW|CTLFLAG_LOCKED, 0, "Generic link-management");
 
@@ -2266,17 +2881,18 @@ void if_rtmtu_update(struct ifnet *ifp)
 }
 
 __private_extern__ void
-if_data_internal_to_if_data(
-       struct ifnet *ifp,
-       const struct if_data_internal   *if_data_int,
-       struct if_data                                  *if_data)
+if_data_internal_to_if_data(struct ifnet *ifp,
+    const struct if_data_internal *if_data_int, struct if_data *if_data)
 {
-       struct dlil_threading_info *thread;
-               if ((thread = ifp->if_input_thread) == NULL || (dlil_multithreaded_input == 0))
-               thread = dlil_lo_thread_ptr;
-
-#define COPYFIELD(fld) if_data->fld = if_data_int->fld
+#pragma unused(ifp)
+#define COPYFIELD(fld)         if_data->fld = if_data_int->fld
 #define COPYFIELD32(fld)       if_data->fld = (u_int32_t)(if_data_int->fld)
+/* compiler will cast down to 32-bit */
+#define        COPYFIELD32_ATOMIC(fld) do {                                            \
+       atomic_get_64(if_data->fld,                                             \
+           (u_int64_t *)(void *)(uintptr_t)&if_data_int->fld);                 \
+} while (0)
+
        COPYFIELD(ifi_type);
        COPYFIELD(ifi_typelen);
        COPYFIELD(ifi_physical);
@@ -2289,29 +2905,28 @@ if_data_internal_to_if_data(
        COPYFIELD(ifi_metric);
        if (if_data_int->ifi_baudrate & 0xFFFFFFFF00000000LL) {
                if_data->ifi_baudrate = 0xFFFFFFFF;
-       }
-       else {
+       } else {
                COPYFIELD32(ifi_baudrate);
        }
+
+       COPYFIELD32_ATOMIC(ifi_ipackets);
+       COPYFIELD32_ATOMIC(ifi_ierrors);
+       COPYFIELD32_ATOMIC(ifi_opackets);
+       COPYFIELD32_ATOMIC(ifi_oerrors);
+       COPYFIELD32_ATOMIC(ifi_collisions);
+       COPYFIELD32_ATOMIC(ifi_ibytes);
+       COPYFIELD32_ATOMIC(ifi_obytes);
+       COPYFIELD32_ATOMIC(ifi_imcasts);
+       COPYFIELD32_ATOMIC(ifi_omcasts);
+       COPYFIELD32_ATOMIC(ifi_iqdrops);
+       COPYFIELD32_ATOMIC(ifi_noproto);
+
+       COPYFIELD(ifi_recvtiming);
+       COPYFIELD(ifi_xmittiming);
        
-       lck_mtx_lock(thread->input_lck);
-       COPYFIELD32(ifi_ipackets);
-       COPYFIELD32(ifi_ierrors);
-       COPYFIELD32(ifi_opackets);
-       COPYFIELD32(ifi_oerrors);
-       COPYFIELD32(ifi_collisions);
-       COPYFIELD32(ifi_ibytes);
-       COPYFIELD32(ifi_obytes);
-       COPYFIELD32(ifi_imcasts);
-       COPYFIELD32(ifi_omcasts);
-       COPYFIELD32(ifi_iqdrops);
-       COPYFIELD32(ifi_noproto);
-       COPYFIELD32(ifi_recvtiming);
-       COPYFIELD32(ifi_xmittiming);
        if_data->ifi_lastchange.tv_sec = if_data_int->ifi_lastchange.tv_sec;
        if_data->ifi_lastchange.tv_usec = if_data_int->ifi_lastchange.tv_usec;
-       lck_mtx_unlock(thread->input_lck);
-       
+
 #if IF_LASTCHANGEUPTIME
        if_data->ifi_lastchange.tv_sec += boottime_sec();
 #endif
@@ -2320,70 +2935,103 @@ if_data_internal_to_if_data(
        COPYFIELD(ifi_hwassist);
        if_data->ifi_reserved1 = 0;
        if_data->ifi_reserved2 = 0;
+#undef COPYFIELD32_ATOMIC
 #undef COPYFIELD32
 #undef COPYFIELD
 }
 
 __private_extern__ void
-if_data_internal_to_if_data64(
-       struct ifnet *ifp,
-       const struct if_data_internal   *if_data_int,
-       struct if_data64                                *if_data64)
+if_data_internal_to_if_data64(struct ifnet *ifp,
+    const struct if_data_internal *if_data_int,
+    struct if_data64 *if_data64)
 {
-       struct dlil_threading_info *thread;
-               if ((thread = ifp->if_input_thread) == NULL || (dlil_multithreaded_input == 0))
-               thread = dlil_lo_thread_ptr;
-
-#define COPYFIELD(fld) if_data64->fld = if_data_int->fld
-       COPYFIELD(ifi_type);
-       COPYFIELD(ifi_typelen);
-       COPYFIELD(ifi_physical);
-       COPYFIELD(ifi_addrlen);
-       COPYFIELD(ifi_hdrlen);
-       COPYFIELD(ifi_recvquota);
-       COPYFIELD(ifi_xmitquota);
+#pragma unused(ifp)
+#define COPYFIELD64(fld)       if_data64->fld = if_data_int->fld
+#define COPYFIELD64_ATOMIC(fld) do {                                           \
+       atomic_get_64(if_data64->fld,                                           \
+       (u_int64_t *)(void *)(uintptr_t)&if_data_int->fld);                     \
+} while (0)
+
+       COPYFIELD64(ifi_type);
+       COPYFIELD64(ifi_typelen);
+       COPYFIELD64(ifi_physical);
+       COPYFIELD64(ifi_addrlen);
+       COPYFIELD64(ifi_hdrlen);
+       COPYFIELD64(ifi_recvquota);
+       COPYFIELD64(ifi_xmitquota);
        if_data64->ifi_unused1 = 0;
-       COPYFIELD(ifi_mtu);
-       COPYFIELD(ifi_metric);
-       COPYFIELD(ifi_baudrate);
-
-       lck_mtx_lock(thread->input_lck);
-       COPYFIELD(ifi_ipackets);
-       COPYFIELD(ifi_ierrors);
-       COPYFIELD(ifi_opackets);
-       COPYFIELD(ifi_oerrors);
-       COPYFIELD(ifi_collisions);
-       COPYFIELD(ifi_ibytes);
-       COPYFIELD(ifi_obytes);
-       COPYFIELD(ifi_imcasts);
-       COPYFIELD(ifi_omcasts);
-       COPYFIELD(ifi_iqdrops);
-       COPYFIELD(ifi_noproto);
-       COPYFIELD(ifi_recvtiming);
-       COPYFIELD(ifi_xmittiming);
+       COPYFIELD64(ifi_mtu);
+       COPYFIELD64(ifi_metric);
+       COPYFIELD64(ifi_baudrate);
+
+       COPYFIELD64_ATOMIC(ifi_ipackets);
+       COPYFIELD64_ATOMIC(ifi_ierrors);
+       COPYFIELD64_ATOMIC(ifi_opackets);
+       COPYFIELD64_ATOMIC(ifi_oerrors);
+       COPYFIELD64_ATOMIC(ifi_collisions);
+       COPYFIELD64_ATOMIC(ifi_ibytes);
+       COPYFIELD64_ATOMIC(ifi_obytes);
+       COPYFIELD64_ATOMIC(ifi_imcasts);
+       COPYFIELD64_ATOMIC(ifi_omcasts);
+       COPYFIELD64_ATOMIC(ifi_iqdrops);
+       COPYFIELD64_ATOMIC(ifi_noproto);
+
+       /* Note these two fields are actually 32 bit, so doing COPYFIELD64_ATOMIC will
+        * cause them to be misaligned
+        */
+       COPYFIELD64(ifi_recvtiming);
+       COPYFIELD64(ifi_xmittiming);
+
        if_data64->ifi_lastchange.tv_sec = if_data_int->ifi_lastchange.tv_sec;
        if_data64->ifi_lastchange.tv_usec = if_data_int->ifi_lastchange.tv_usec;
-       lck_mtx_unlock(thread->input_lck);
-       
+
 #if IF_LASTCHANGEUPTIME
        if_data64->ifi_lastchange.tv_sec += boottime_sec();
 #endif
 
-#undef COPYFIELD
+#undef COPYFIELD64
 }
 
-void
-ifafree(struct ifaddr *ifa)
+__private_extern__ void
+if_copy_traffic_class(struct ifnet *ifp,
+    struct if_traffic_class *if_tc)
 {
-       int oldval;
+#define COPY_IF_TC_FIELD64_ATOMIC(fld) do {                            \
+       atomic_get_64(if_tc->fld,                                                       \
+       (u_int64_t *)(void *)(uintptr_t)&ifp->if_tc.fld);       \
+} while (0)
+
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ibkpackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ibkbytes);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_obkpackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_obkbytes);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ivipackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ivibytes);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ovipackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ovibytes);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ivopackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ivobytes);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ovopackets);
+       COPY_IF_TC_FIELD64_ATOMIC(ifi_ovobytes);
+
+#undef COPY_IF_TC_FIELD64_ATOMIC
+}
 
-       oldval = OSAddAtomic(-1, &ifa->ifa_refcnt);
-       if (oldval >= 1 && ifa->ifa_trace != NULL)
-               (*ifa->ifa_trace)(ifa, FALSE);
-       if (oldval == 0) {
+
+struct ifaddr *
+ifa_remref(struct ifaddr *ifa, int locked)
+{
+       if (!locked)
+               IFA_LOCK_SPIN(ifa);
+       else
+               IFA_LOCK_ASSERT_HELD(ifa);
+
+       if (ifa->ifa_refcnt == 0)
                panic("%s: ifa %p negative refcnt\n", __func__, ifa);
-       } else if (oldval == 1) {
-               if  (ifa->ifa_debug & IFD_ATTACHED)
+       else if (ifa->ifa_trace != NULL)
+               (*ifa->ifa_trace)(ifa, FALSE);
+       if (--ifa->ifa_refcnt == 0) {
+               if (ifa->ifa_debug & IFD_ATTACHED)
                        panic("ifa %p attached to ifp is being freed\n", ifa);
                /*
                 * Some interface addresses are allocated either statically
@@ -2393,22 +3041,54 @@ ifafree(struct ifaddr *ifa)
                 * leave it alone.
                 */
                if (ifa->ifa_debug & IFD_ALLOC) {
-                       if (ifa->ifa_free == NULL)
+                       if (ifa->ifa_free == NULL) {
+                               IFA_UNLOCK(ifa);
                                FREE(ifa, M_IFADDR);
-                       else
+                       } else {
+                               /* Become a regular mutex */
+                               IFA_CONVERT_LOCK(ifa);
+                               /* callee will unlock */
                                (*ifa->ifa_free)(ifa);
+                       }
+               } else {
+                       IFA_UNLOCK(ifa);
                }
+               ifa = NULL;
        }
+
+       if (!locked && ifa != NULL)
+               IFA_UNLOCK(ifa);
+
+       return (ifa);
 }
 
 void
-ifaref(struct ifaddr *ifa)
+ifa_addref(struct ifaddr *ifa, int locked)
 {
-       int oldval;
+       if (!locked)
+               IFA_LOCK_SPIN(ifa);
+       else
+               IFA_LOCK_ASSERT_HELD(ifa);
 
-       oldval = OSAddAtomic(1, &ifa->ifa_refcnt);
-       if (oldval < 0)
-               panic("%s: ifa %p negative refcnt\n", __func__, ifa);
-       else if (ifa->ifa_trace != NULL)
+       if (++ifa->ifa_refcnt == 0) {
+               panic("%s: ifa %p wraparound refcnt\n", __func__, ifa);
+               /* NOTREACHED */
+       } else if (ifa->ifa_trace != NULL) {
                (*ifa->ifa_trace)(ifa, TRUE);
+       }
+       if (!locked)
+               IFA_UNLOCK(ifa);
+}
+
+void
+ifa_lock_init(struct ifaddr *ifa)
+{
+       lck_mtx_init(&ifa->ifa_lock, ifa_mtx_grp, ifa_mtx_attr);
+}
+
+void
+ifa_lock_destroy(struct ifaddr *ifa)
+{
+       IFA_LOCK_ASSERT_NOTHELD(ifa);
+       lck_mtx_destroy(&ifa->ifa_lock, ifa_mtx_grp);
 }