]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/netinet/ip_output.c
xnu-1699.22.81.tar.gz
[apple/xnu.git] / bsd / netinet / ip_output.c
index e4dc272d826184e767db39824ad9157a46bfd200..57f522919a7f2cbc19a127ac11a996e8194a96e0 100644 (file)
@@ -1,31 +1,29 @@
 /*
- * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
+ * Copyright (c) 2000-2011 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This file contains Original Code and/or Modifications of Original Code 
- * as defined in and that are subject to the Apple Public Source License 
- * Version 2.0 (the 'License'). You may not use this file except in 
- * compliance with the License.  The rights granted to you under the 
- * License may not be used to create, or enable the creation or 
- * redistribution of, unlawful or unlicensed copies of an Apple operating 
- * system, or to circumvent, violate, or enable the circumvention or 
- * violation of, any terms of an Apple operating system software license 
- * agreement.
- *
- * Please obtain a copy of the License at 
- * http://www.opensource.apple.com/apsl/ and read it before using this 
- * file.
- *
- * The Original Code and all software distributed under the License are 
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
- * Please see the License for the specific language governing rights and 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
  * limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * Copyright (c) 1982, 1986, 1988, 1990, 1993
  *     @(#)ip_output.c 8.3 (Berkeley) 1/21/94
  * $FreeBSD: src/sys/netinet/ip_output.c,v 1.99.2.16 2001/07/19 06:37:26 kris Exp $
  */
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections.  This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
+ */
 
 #define _IP_VHL
 
 #include <sys/socketvar.h>
 #include <kern/locks.h>
 #include <sys/sysctl.h>
+#include <sys/mcache.h>
+
+#include <machine/endian.h>
+#include <pexpert/pexpert.h>
 
 #include <net/if.h>
+#include <net/if_dl.h>
+#include <net/if_types.h>
 #include <net/route.h>
+#include <net/ntstat.h>
+#include <net/net_osdep.h>
 
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 
 #include <netinet/kpi_ipfilter_var.h>
 
+#if CONFIG_MACF_NET
+#include <security/mac_framework.h>
+#endif
+
 #include "faith.h"
 
 #include <net/dlil.h>
 #include <sys/kdebug.h>
+#include <libkern/OSAtomic.h>
 
 #define DBG_LAYER_BEG          NETDBG_CODE(DBG_NETIP, 1)
 #define DBG_LAYER_END          NETDBG_CODE(DBG_NETIP, 3)
 #define DBG_FNC_IP_OUTPUT      NETDBG_CODE(DBG_NETIP, (1 << 8) | 1)
 #define DBG_FNC_IPSEC4_OUTPUT  NETDBG_CODE(DBG_NETIP, (2 << 8) | 1)
 
+#define        SWAP16(v) ((((v) & 0xff) << 8) | ((v) >> 8))
 
 #if IPSEC
 #include <netinet6/ipsec.h>
 
 #include <netinet/ip_fw.h>
 #include <netinet/ip_divert.h>
+#include <mach/sdt.h>
 
 #if DUMMYNET
 #include <netinet/ip_dummynet.h>
 #endif
 
+#if PF
+#include <net/pfvar.h>
+#endif /* PF */
+
 #if IPFIREWALL_FORWARD_DEBUG
 #define print_ip(a)     printf("%ld.%ld.%ld.%ld",(ntohl(a.s_addr)>>24)&0xFF,\
                                                  (ntohl(a.s_addr)>>16)&0xFF,\
                                                  (ntohl(a.s_addr))&0xFF);
 #endif
 
-#if IPSEC
-extern lck_mtx_t    *sadb_mutex;
-#endif
 
 u_short ip_id;
 
 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
-static struct ifnet *ip_multicast_if(struct in_addr *, int *);
 static void    ip_mloopback(struct ifnet *, struct mbuf *,
        struct sockaddr_in *, int);
-static int     ip_getmoptions(struct sockopt *, struct ip_moptions *);
 static int     ip_pcbopts(int, struct mbuf **, struct mbuf *);
-static int     ip_setmoptions(struct sockopt *, struct ip_moptions **);
+static void    imo_trace(struct ip_moptions *, int);
+
+static void ip_out_cksum_stats(int, u_int32_t);
+static struct ifaddr *in_selectsrcif(struct ip *, struct route *, unsigned int);
 
-int ip_createmoptions(struct ip_moptions **imop);
-int ip_addmembership(struct ip_moptions *imo, struct ip_mreq *mreq);
-int ip_dropmembership(struct ip_moptions *imo, struct ip_mreq *mreq);
 int    ip_optcopy(struct ip *, struct ip *);
-extern int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **);
-#ifdef __APPLE__
-extern struct mbuf*    m_dup(register struct mbuf *m, int how);
-#endif
+void in_delayed_cksum_offset(struct mbuf *, int );
+void in_cksum_offset(struct mbuf* , size_t );
 
-extern int apple_hwcksum_tx;
-extern u_long  route_generation;
+extern int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **);
 
 extern struct protosw inetsw[];
 
@@ -160,8 +175,50 @@ extern int ipsec_bypass;
 #endif
 
 static int     ip_maxchainsent = 0;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, maxchainsent, CTLFLAG_RW,
+SYSCTL_INT(_net_inet_ip, OID_AUTO, maxchainsent, CTLFLAG_RW | CTLFLAG_LOCKED,
     &ip_maxchainsent, 0, "use dlil_output_list");
+#if DEBUG
+static int forge_ce = 0;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, forge_ce, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &forge_ce, 0, "Forge ECN CE");
+#endif /* DEBUG */
+
+static int ip_select_srcif_debug = 0;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, select_srcif_debug, CTLFLAG_RW | CTLFLAG_LOCKED,
+    &ip_select_srcif_debug, 0, "log source interface selection debug info");
+
+#define        IMO_TRACE_HIST_SIZE     32      /* size of trace history */
+
+/* For gdb */
+__private_extern__ unsigned int imo_trace_hist_size = IMO_TRACE_HIST_SIZE;
+
+struct ip_moptions_dbg {
+       struct ip_moptions      imo;                    /* ip_moptions */
+       u_int16_t               imo_refhold_cnt;        /* # of IMO_ADDREF */
+       u_int16_t               imo_refrele_cnt;        /* # of IMO_REMREF */
+       /*
+        * Alloc and free callers.
+        */
+       ctrace_t                imo_alloc;
+       ctrace_t                imo_free;
+       /*
+        * Circular lists of IMO_ADDREF and IMO_REMREF callers.
+        */
+       ctrace_t                imo_refhold[IMO_TRACE_HIST_SIZE];
+       ctrace_t                imo_refrele[IMO_TRACE_HIST_SIZE];
+};
+
+#if DEBUG
+static unsigned int imo_debug = 1;     /* debugging (enabled) */
+#else
+static unsigned int imo_debug;         /* debugging (disabled) */
+#endif /* !DEBUG */
+static unsigned int imo_size;          /* size of zone element */
+static struct zone *imo_zone;          /* zone for ip_moptions */
+
+#define        IMO_ZONE_MAX            64              /* maximum elements in zone */
+#define        IMO_ZONE_NAME           "ip_moptions"   /* zone name */
+
 /*
  * IP output.  The packet in mbuf chain m contains a skeletal IP
  * header (with len, off, ttl, proto, tos, src, dst).
@@ -174,13 +231,36 @@ ip_output(
        struct mbuf *opt,
        struct route *ro,
        int flags,
-       struct ip_moptions *imo)
+       struct ip_moptions *imo,
+       struct ip_out_args *ipoa)
 {
        int error;
-       error = ip_output_list(m0, 0, opt, ro, flags, imo);
+       error = ip_output_list(m0, 0, opt, ro, flags, imo, ipoa);
        return error;
 }
 
+/*
+ * Returns:    0                       Success
+ *             ENOMEM
+ *             EADDRNOTAVAIL
+ *             ENETUNREACH
+ *             EHOSTUNREACH
+ *             EACCES
+ *             EMSGSIZE
+ *             ENOBUFS
+ *     ipsec4_getpolicybyaddr:???      [IPSEC 4th argument, contents modified]
+ *     ipsec4_getpolicybysock:???      [IPSEC 4th argument, contents modified]
+ *     key_spdacquire:???              [IPSEC]
+ *     ipsec4_output:???               [IPSEC]
+ *     <fr_checkp>:???                 [firewall]
+ *     ip_dn_io_ptr:???                [dummynet]
+ *     dlil_output:???                 [DLIL]
+ *     dlil_output_list:???            [DLIL]
+ *
+ * Notes:      The ipsec4_getpolicyby{addr|sock} function error returns are
+ *             only used as the error return from this function where one of
+ *             these functions fails to return a policy.
+ */
 int
 ip_output_list(
        struct mbuf *m0,
@@ -188,17 +268,20 @@ ip_output_list(
        struct mbuf *opt,
        struct route *ro,
        int flags,
-       struct ip_moptions *imo)
+       struct ip_moptions *imo,
+       struct ip_out_args *ipoa
+       )
 {
-       struct ip *ip, *mhip;
+       struct ip *ip;
        struct ifnet *ifp = NULL;
-       struct mbuf *m = m0;
+       struct mbuf *m = m0, **mppn = NULL;
        int hlen = sizeof (struct ip);
-       int len, off, error = 0;
+       int len = 0, error = 0;
        struct sockaddr_in *dst = NULL;
-       struct in_ifaddr *ia = NULL;
+       struct in_ifaddr *ia = NULL, *src_ia = NULL;
        int isbroadcast, sw_csum;
        struct in_addr pkt_dst;
+       struct ipf_pktopts *ippo = NULL, ipf_pktopts;
 #if IPSEC
        struct route iproute;
        struct socket *so = NULL;
@@ -207,63 +290,88 @@ ip_output_list(
 #if IPFIREWALL_FORWARD
        int fwd_rewrite_src = 0;
 #endif
+#if IPFIREWALL
+       int off;
        struct ip_fw_args args;
+       struct m_tag    *tag;
+       struct sockaddr_in *next_hop_from_ipfwd_tag = NULL;
+#endif
        int didfilter = 0;
        ipfilter_t inject_filter_ref = 0;
-       struct m_tag    *tag;
-       struct route    dn_route;
+#if DUMMYNET
+       struct route    saved_route;
+       struct ip_out_args saved_ipoa;
+       struct sockaddr_in dst_buf;
+#endif /* DUMMYNET */
        struct mbuf * packetlist;
-       int pktcnt = 0;
-       
-       lck_mtx_lock(ip_mutex); 
-
+       int pktcnt = 0, tso = 0;
+       u_int32_t       bytecnt = 0;
+       unsigned int ifscope;
+       unsigned int nocell;
+       boolean_t select_srcif;
        KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
 
        packetlist = m0;
+#if IPFIREWALL
+       args.next_hop = NULL;
        args.eh = NULL;
        args.rule = NULL;
-       args.next_hop = NULL;
        args.divert_rule = 0;                   /* divert cookie */
-       
+       args.ipoa = NULL;
+
+       if (SLIST_EMPTY(&m0->m_pkthdr.tags))
+               goto ipfw_tags_done;
+
        /* Grab info from mtags prepended to the chain */
 #if DUMMYNET
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
                struct dn_pkt_tag       *dn_tag;
-               
+
                dn_tag = (struct dn_pkt_tag *)(tag+1);
                args.rule = dn_tag->rule;
                opt = NULL;
-               dn_route = dn_tag->ro;
-               ro = &dn_route;
-                       
+               saved_route = dn_tag->ro;
+               ro = &saved_route;
+
                imo = NULL;
-               dst = dn_tag->dn_dst;
+               bcopy(&dn_tag->dn_dst, &dst_buf, sizeof(dst_buf));
+               dst = &dst_buf;
                ifp = dn_tag->ifp;
                flags = dn_tag->flags;
-               
+               saved_ipoa = dn_tag->ipoa;
+               ipoa = &saved_ipoa;
+
                m_tag_delete(m0, tag);
        }
 #endif /* DUMMYNET */
 
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
+#if IPDIVERT
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
                struct divert_tag       *div_tag;
-               
+
                div_tag = (struct divert_tag *)(tag+1);
                args.divert_rule = div_tag->cookie;
 
                m_tag_delete(m0, tag);
        }
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
+#endif /* IPDIVERT */
+
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
                struct ip_fwd_tag       *ipfwd_tag;
-               
+
                ipfwd_tag = (struct ip_fwd_tag *)(tag+1);
-               args.next_hop = ipfwd_tag->next_hop;
+               next_hop_from_ipfwd_tag = ipfwd_tag->next_hop;
                
                m_tag_delete(m0, tag);
        }
+ipfw_tags_done:
+#endif /* IPFIREWALL */
 
        m = m0;
-       
+
 #if    DIAGNOSTIC
        if ( !m || (m->m_flags & M_PKTHDR) != 0)
                panic("ip_output no HDR");
@@ -272,21 +380,56 @@ ip_output_list(
                      mtod(m, struct ip *)->ip_p);
 #endif
 
+       bzero(&ipf_pktopts, sizeof(struct ipf_pktopts));
+       ippo = &ipf_pktopts;
+
+       /*
+        * At present the IP_OUTARGS flag implies a request for IP to
+        * perform source interface selection.  In the forwarding case,
+        * only the ifscope value is used, as source interface selection
+        * doesn't take place.
+        */
+       if (ip_doscopedroute && (flags & IP_OUTARGS)) {
+               select_srcif = !(flags & IP_FORWARDING);
+               ifscope = ipoa->ipoa_boundif;
+               ipf_pktopts.ippo_flags = IPPOF_BOUND_IF;
+               ipf_pktopts.ippo_flags |= (ifscope << IPPOF_SHIFT_IFSCOPE);
+       } else {
+               select_srcif = FALSE;
+               ifscope = IFSCOPE_NONE;
+       }
+
+       if (flags & IP_OUTARGS) {
+               nocell = ipoa->ipoa_nocell;
+               if (nocell)
+                       ipf_pktopts.ippo_flags |= IPPOF_NO_IFT_CELLULAR;
+       } else {
+               nocell = 0;
+       }
+
+#if IPFIREWALL
        if (args.rule != NULL) {        /* dummynet already saw us */
-            ip = mtod(m, struct ip *);
-            hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
-            if (ro->ro_rt != NULL)
-                ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
-                       if (ia)
-                               ifaref(&ia->ia_ifa);
-#if IPSEC
-                       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-                               so = ipsec_getsocket(m);
-                               (void)ipsec_setsocket(m, NULL);
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
+               if (ro->ro_rt != NULL) {
+                       RT_LOCK_SPIN(ro->ro_rt);
+                       ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
+                       if (ia) {
+                               /* Become a regular mutex */
+                               RT_CONVERT_LOCK(ro->ro_rt);
+                               IFA_ADDREF(&ia->ia_ifa);
                        }
+                       RT_UNLOCK(ro->ro_rt);
+               }
+#if IPSEC
+               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
+                       so = ipsec_getsocket(m);
+                       (void)ipsec_setsocket(m, NULL);
+               }
 #endif
-            goto sendit;
+               goto sendit;
        }
+#endif /* IPFIREWALL */
 
 #if IPSEC
        if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
@@ -299,14 +442,39 @@ loopit:
         * No need to proccess packet twice if we've 
         * already seen it
         */
-       inject_filter_ref = ipf_get_inject_filter(m);
+       if (!SLIST_EMPTY(&m->m_pkthdr.tags))
+               inject_filter_ref = ipf_get_inject_filter(m);
+       else
+               inject_filter_ref = 0;
 
        if (opt) {
                m = ip_insertoptions(m, opt, &len);
                hlen = len;
        }
        ip = mtod(m, struct ip *);
+#if IPFIREWALL
+       /*
+        * rdar://8542331
+        *
+        * When dealing with a packet chain, we need to reset "next_hop" because 
+        * "dst" may have been changed to the gateway address below for the previous
+        * packet of the chain. This could cause the route to be inavertandly changed 
+        * to the route to the gateway address (instead of the route to the destination).
+        */
+       args.next_hop = next_hop_from_ipfwd_tag;
        pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
+#else
+       pkt_dst = ip->ip_dst;
+#endif
+
+       /*
+        * We must not send if the packet is destined to network zero.
+        * RFC1122 3.2.1.3 (a) and (b).
+        */
+       if (IN_ZERONET(ntohl(pkt_dst.s_addr))) {
+               error = EHOSTUNREACH;
+               goto bad;
+       }
 
        /*
         * Fill in IP header.
@@ -319,14 +487,24 @@ loopit:
 #else
                ip->ip_id = htons(ip_id++);
 #endif
-               ipstat.ips_localout++;
+               OSAddAtomic(1, &ipstat.ips_localout);
        } else {
                hlen = IP_VHL_HL(ip->ip_vhl) << 2;
        }
+       
+#if DEBUG
+       /* For debugging, we let the stack forge congestion */
+       if (forge_ce != 0 &&
+               ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_ECT1 ||
+                (ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_ECT0)) {
+               ip->ip_tos = (ip->ip_tos & ~IPTOS_ECN_MASK) | IPTOS_ECN_CE;
+               forge_ce--;
+       }
+#endif /* DEBUG */
 
        KERNEL_DEBUG(DBG_LAYER_BEG, ip->ip_dst.s_addr, 
                     ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
-
+       
        dst = (struct sockaddr_in *)&ro->ro_dst;
 
        /*
@@ -337,21 +515,39 @@ loopit:
         * cache with IPv6.
         */
 
-       {
-               if (ro->ro_rt && (ro->ro_rt->generation_id != route_generation) &&
-                       ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0) && (ip->ip_src.s_addr != INADDR_ANY) &&
-                       (ifa_foraddr(ip->ip_src.s_addr) == 0)) {
-                       error = EADDRNOTAVAIL;
-                       goto bad;
+       if (ro->ro_rt != NULL) {
+               if (ro->ro_rt->generation_id != route_generation &&
+                   ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0) &&
+                   (ip->ip_src.s_addr != INADDR_ANY)) {
+                       src_ia = ifa_foraddr(ip->ip_src.s_addr);
+                       if (src_ia == NULL) {
+                               error = EADDRNOTAVAIL;
+                               goto bad;
+                       }
+                       IFA_REMREF(&src_ia->ia_ifa);
                }
+               /*
+                * Test rt_flags without holding rt_lock for performance
+                * reasons; if the route is down it will hopefully be
+                * caught by the layer below (since it uses this route
+                * as a hint) or during the next transmit.
+                */
+               if ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
+                   dst->sin_family != AF_INET ||
+                   dst->sin_addr.s_addr != pkt_dst.s_addr) {
+                       rtfree(ro->ro_rt);
+                       ro->ro_rt = NULL;
+               }
+               /*
+                * If we're doing source interface selection, we may not
+                * want to use this route; only synch up the generation
+                * count otherwise.
+                */
+               if (!select_srcif && ro->ro_rt != NULL &&
+                   ro->ro_rt->generation_id != route_generation)
+                       ro->ro_rt->generation_id = route_generation;
        }
-       if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
-          dst->sin_family != AF_INET ||
-          dst->sin_addr.s_addr != pkt_dst.s_addr)) {
-               rtfree(ro->ro_rt);
-               ro->ro_rt = (struct rtentry *)0;
-       }
-       if (ro->ro_rt == 0) {
+       if (ro->ro_rt == NULL) {
                bzero(dst, sizeof(*dst));
                dst->sin_family = AF_INET;
                dst->sin_len = sizeof(*dst);
@@ -365,10 +561,10 @@ loopit:
 #define sintosa(sin)   ((struct sockaddr *)(sin))
        if (flags & IP_ROUTETOIF) {
                if (ia)
-                       ifafree(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
                if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0) {
                        if ((ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
-                               ipstat.ips_noroute++;
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
                                goto bad;
                        }
@@ -376,7 +572,85 @@ loopit:
                ifp = ia->ia_ifp;
                ip->ip_ttl = 1;
                isbroadcast = in_broadcast(dst->sin_addr, ifp);
+       } else if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) &&
+           imo != NULL && (ifp = imo->imo_multicast_ifp) != NULL) {
+               /*
+                * Bypass the normal routing lookup for multicast
+                * packets if the interface is specified.
+                */
+               isbroadcast = 0;
+               if (ia != NULL)
+                       IFA_REMREF(&ia->ia_ifa);
+
+               /* Macro takes reference on ia */
+               IFP_TO_IA(ifp, ia);
        } else {
+               boolean_t cloneok = FALSE;
+               /*
+                * Perform source interface selection; the source IP address
+                * must belong to one of the addresses of the interface used
+                * by the route.  For performance reasons, do this only if
+                * there is no route, or if the routing table has changed,
+                * or if we haven't done source interface selection on this
+                * route (for this PCB instance) before.
+                */
+               if (select_srcif && ip->ip_src.s_addr != INADDR_ANY &&
+                   (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP) ||
+                   ro->ro_rt->generation_id != route_generation ||
+                   !(ro->ro_flags & ROF_SRCIF_SELECTED))) {
+                       struct ifaddr *ifa;
+
+                       /* Find the source interface */
+                       ifa = in_selectsrcif(ip, ro, ifscope);
+
+                       /*
+                        * If the source address belongs to a cellular interface
+                        * and the caller forbids our using interfaces of such
+                        * type, pretend that there is no source address.
+                        */
+                       if (nocell && ifa != NULL &&
+                           ifa->ifa_ifp->if_type == IFT_CELLULAR) {
+                               IFA_REMREF(ifa);
+                               error = EADDRNOTAVAIL;
+                               goto bad;
+                       }
+
+                       /*
+                        * If the source address is spoofed (in the case
+                        * of IP_RAWOUTPUT), or if this is destined for
+                        * local/loopback, just let it go out using the
+                        * interface of the route.  Otherwise, there's no
+                        * interface having such an address, so bail out.
+                        */
+                       if (ifa == NULL && !(flags & IP_RAWOUTPUT) &&
+                           ifscope != lo_ifp->if_index) {
+                               error = EADDRNOTAVAIL;
+                               goto bad;
+                       }
+
+                       /*
+                        * If the caller didn't explicitly specify the scope,
+                        * pick it up from the source interface.  If the cached
+                        * route was wrong and was blown away as part of source
+                        * interface selection, don't mask out RTF_PRCLONING
+                        * since that route may have been allocated by the ULP,
+                        * unless the IP header was created by the caller or
+                        * the destination is IPv4 LLA.  The check for the
+                        * latter is needed because IPv4 LLAs are never scoped
+                        * in the current implementation, and we don't want to
+                        * replace the resolved IPv4 LLA route with one whose
+                        * gateway points to that of the default gateway on
+                        * the primary interface of the system.
+                        */
+                       if (ifa != NULL) {
+                               if (ifscope == IFSCOPE_NONE)
+                                       ifscope = ifa->ifa_ifp->if_index;
+                               IFA_REMREF(ifa);
+                               cloneok = (!(flags & IP_RAWOUTPUT) &&
+                                   !(IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))));
+                       }
+               }
+
                /*
                 * If this is the case, we probably don't want to allocate
                 * a protocol-cloned route since we didn't get one from the
@@ -386,29 +660,95 @@ loopit:
                 * the link layer, as this is probably required in all cases
                 * for correct operation (as it is for ARP).
                 */
-               if (ro->ro_rt == 0)
-                       rtalloc_ign(ro, RTF_PRCLONING);
-               if (ro->ro_rt == 0) {
-                       ipstat.ips_noroute++;
+               if (ro->ro_rt == NULL) {
+                       unsigned long ign = RTF_PRCLONING;
+                       /*
+                        * We make an exception here: if the destination
+                        * address is INADDR_BROADCAST, allocate a protocol-
+                        * cloned host route so that we end up with a route
+                        * marked with the RTF_BROADCAST flag.  Otherwise,
+                        * we would end up referring to the default route,
+                        * instead of creating a cloned host route entry.
+                        * That would introduce inconsistencies between ULPs
+                        * that allocate a route and those that don't.  The
+                        * RTF_BROADCAST route is important since we'd want
+                        * to send out undirected IP broadcast packets using
+                        * link-level broadcast address. Another exception
+                        * is for ULP-created routes that got blown away by
+                        * source interface selection (see above).
+                        *
+                        * These exceptions will no longer be necessary when
+                        * the RTF_PRCLONING scheme is no longer present.
+                        */
+                       if (cloneok || dst->sin_addr.s_addr == INADDR_BROADCAST)
+                               ign &= ~RTF_PRCLONING;
+
+                       /*
+                        * Loosen the route lookup criteria if the ifscope
+                        * corresponds to the loopback interface; this is
+                        * needed to support Application Layer Gateways
+                        * listening on loopback, in conjunction with packet
+                        * filter redirection rules.  The final source IP
+                        * address will be rewritten by the packet filter
+                        * prior to the RFC1122 loopback check below.
+                        */
+                       if (ifscope == lo_ifp->if_index)
+                               rtalloc_ign(ro, ign);
+                       else
+                               rtalloc_scoped_ign(ro, ign, ifscope);
+
+                       /*
+                        * If the route points to a cellular interface and the
+                        * caller forbids our using interfaces of such type,
+                        * pretend that there is no route.
+                        */
+                       if (nocell && ro->ro_rt != NULL) {
+                               RT_LOCK_SPIN(ro->ro_rt);
+                               if (ro->ro_rt->rt_ifp->if_type ==
+                                   IFT_CELLULAR) {
+                                       RT_UNLOCK(ro->ro_rt);
+                                       rtfree(ro->ro_rt);
+                                       ro->ro_rt = NULL;
+                               } else {
+                                       RT_UNLOCK(ro->ro_rt);
+                               }
+                       }
+               }
+
+               if (ro->ro_rt == NULL) {
+                       OSAddAtomic(1, &ipstat.ips_noroute);
                        error = EHOSTUNREACH;
                        goto bad;
                }
+
                if (ia)
-                       ifafree(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
+               RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
-               if (ia)
-                       ifaref(&ia->ia_ifa);
+               if (ia) {
+                       /* Become a regular mutex */
+                       RT_CONVERT_LOCK(ro->ro_rt);
+                       IFA_ADDREF(&ia->ia_ifa);
+               }
                ifp = ro->ro_rt->rt_ifp;
                ro->ro_rt->rt_use++;
                if (ro->ro_rt->rt_flags & RTF_GATEWAY)
                        dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
-               if (ro->ro_rt->rt_flags & RTF_HOST)
+               if (ro->ro_rt->rt_flags & RTF_HOST) {
                        isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
-               else
+               } else {
+                       /* Become a regular mutex */
+                       RT_CONVERT_LOCK(ro->ro_rt);
                        isbroadcast = in_broadcast(dst->sin_addr, ifp);
+               }
+               RT_UNLOCK(ro->ro_rt);
        }
+
        if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
                struct in_multi *inm;
+               u_int32_t vif;
+               u_int8_t ttl = IP_DEFAULT_MULTICAST_TTL;
+               u_int8_t loop = IP_DEFAULT_MULTICAST_LOOP;
 
                m->m_flags |= M_MCAST;
                /*
@@ -421,22 +761,30 @@ loopit:
                 * See if the caller provided any multicast options
                 */
                if (imo != NULL) {
-                       if ((flags & IP_RAWOUTPUT) == 0) ip->ip_ttl = imo->imo_multicast_ttl;
-                       if (imo->imo_multicast_ifp != NULL) {
+                       IMO_LOCK(imo);
+                       vif = imo->imo_multicast_vif;
+                       ttl = imo->imo_multicast_ttl;
+                       loop = imo->imo_multicast_loop;
+                       if ((flags & IP_RAWOUTPUT) == 0)
+                               ip->ip_ttl = ttl;
+                       if (imo->imo_multicast_ifp != NULL)
                                ifp = imo->imo_multicast_ifp;
-                       }
-                       if (imo->imo_multicast_vif != -1 && 
-                               ((flags & IP_RAWOUTPUT) == 0 || ip->ip_src.s_addr == INADDR_ANY))
-                               ip->ip_src.s_addr =
-                                       ip_mcast_src(imo->imo_multicast_vif);
-               } else
-                       if ((flags & IP_RAWOUTPUT) == 0) ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
+                       IMO_UNLOCK(imo);
+#if MROUTING
+                       if (vif != -1 && ((flags & IP_RAWOUTPUT) == 0 ||
+                           ip->ip_src.s_addr == INADDR_ANY))
+                               ip->ip_src.s_addr = ip_mcast_src(vif);
+#endif /* MROUTING */
+               } else if ((flags & IP_RAWOUTPUT) == 0) {
+                       vif = -1;
+                       ip->ip_ttl = ttl;
+               }
                /*
                 * Confirm that the outgoing interface supports multicast.
                 */
-               if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
+               if (imo == NULL || vif == -1) {
                        if ((ifp->if_flags & IFF_MULTICAST) == 0) {
-                               ipstat.ips_noroute++;
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
                                goto bad;
                        }
@@ -446,25 +794,28 @@ loopit:
                 * of outgoing interface.
                 */
                if (ip->ip_src.s_addr == INADDR_ANY) {
-                       register struct in_ifaddr *ia1;
-
-                       TAILQ_FOREACH(ia1, &in_ifaddrhead, ia_link)
+                       struct in_ifaddr *ia1;
+                       lck_rw_lock_shared(in_ifaddr_rwlock);
+                       TAILQ_FOREACH(ia1, &in_ifaddrhead, ia_link) {
+                               IFA_LOCK_SPIN(&ia1->ia_ifa);
                                if (ia1->ia_ifp == ifp) {
                                        ip->ip_src = IA_SIN(ia1)->sin_addr;
-                                       
+                                       IFA_UNLOCK(&ia1->ia_ifa);
                                        break;
                                }
+                               IFA_UNLOCK(&ia1->ia_ifa);
+                       }
+                       lck_rw_done(in_ifaddr_rwlock);
                        if (ip->ip_src.s_addr == INADDR_ANY) {
                                error = ENETUNREACH;
                                goto bad;
                        }
                }
 
-               ifnet_lock_shared(ifp);
-               IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
-               ifnet_lock_done(ifp);
-               if (inm != NULL &&
-                  (imo == NULL || imo->imo_multicast_loop)) {
+               in_multihead_lock_shared();
+               IN_LOOKUP_MULTI(&pkt_dst, ifp, inm);
+               in_multihead_lock_done();
+               if (inm != NULL && (imo == NULL || loop)) {
                        /*
                         * If we belong to the destination multicast group
                         * on the outgoing interface, and the caller did not
@@ -473,17 +824,23 @@ loopit:
                        if (!TAILQ_EMPTY(&ipv4_filters)) {
                                struct ipfilter *filter;
                                int seen = (inject_filter_ref == 0);
-                               struct ipf_pktopts *ippo = 0, ipf_pktopts;
 
-                               if (imo) {                                              
-                                       ippo = &ipf_pktopts;
-                                       ipf_pktopts.ippo_mcast_ifnet = imo->imo_multicast_ifp;
-                                       ipf_pktopts.ippo_mcast_ttl = imo->imo_multicast_ttl;
-                                       ipf_pktopts.ippo_mcast_loop = imo->imo_multicast_loop;
+                               if (imo != NULL) {
+                                       ipf_pktopts.ippo_flags |= IPPOF_MCAST_OPTS;
+                                       ipf_pktopts.ippo_mcast_ifnet = ifp;
+                                       ipf_pktopts.ippo_mcast_ttl = ttl;
+                                       ipf_pktopts.ippo_mcast_loop = loop;
                                }
-                               
-                               lck_mtx_unlock(ip_mutex);
+
                                ipf_ref();
+
+                               /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
+                               HTONS(ip->ip_len);
+                               HTONS(ip->ip_off);
+#endif
+
                                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                                        if (seen == 0) {
                                                if ((struct ipfilter *)inject_filter_ref == filter)
@@ -493,21 +850,31 @@ loopit:
                                                result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, ippo);
                                                if (result == EJUSTRETURN) {
                                                        ipf_unref();
+                                                       INM_REMREF(inm);
                                                        goto done;
                                                }
                                                if (result != 0) {
                                                        ipf_unref();
-                                                       lck_mtx_lock(ip_mutex);
+                                                       INM_REMREF(inm);
                                                        goto bad;
                                                }
                                        }
                                }
-                               lck_mtx_lock(ip_mutex);
+
+                               /* set back to host byte order */
+                               ip = mtod(m, struct ip *);
+
+#if BYTE_ORDER != BIG_ENDIAN
+                               NTOHS(ip->ip_len);
+                               NTOHS(ip->ip_off);
+#endif
+
                                ipf_unref();
                                didfilter = 1;
                        }
                        ip_mloopback(ifp, m, dst, hlen);
                }
+#if MROUTING
                else {
                        /*
                         * If we are acting as a multicast router, perform
@@ -529,15 +896,18 @@ loopit:
                                 * as prescribed by rsvpd.
                                 */
                                if (!rsvp_on)
-                                 imo = NULL;
+                                       imo = NULL;
                                if (ip_mforward(ip, ifp, m, imo) != 0) {
                                        m_freem(m);
-                                       lck_mtx_unlock(ip_mutex);
+                                       if (inm != NULL)
+                                               INM_REMREF(inm);
                                        goto done;
                                }
                        }
                }
-
+#endif /* MROUTING */
+               if (inm != NULL)
+                       INM_REMREF(inm);
                /*
                 * Multicasts with a time-to-live of zero may be looped-
                 * back, above, but must not be transmitted on a network.
@@ -548,7 +918,6 @@ loopit:
                 */
                if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
                        m_freem(m);
-                       lck_mtx_unlock(ip_mutex);
                        goto done;
                }
 
@@ -560,7 +929,9 @@ loopit:
         * of outgoing interface.
         */
        if (ip->ip_src.s_addr == INADDR_ANY) {
+               IFA_LOCK_SPIN(&ia->ia_ifa);
                ip->ip_src = IA_SIN(ia)->sin_addr;
+               IFA_UNLOCK(&ia->ia_ifa);
 #if IPFIREWALL_FORWARD
                /* Keep note that we did this - if the firewall changes
                 * the next-hop, our interface may change, changing the
@@ -597,6 +968,33 @@ loopit:
        }
 
 sendit:
+#if PF
+       /* Invoke outbound packet filter */
+       if ( PF_IS_ENABLED) {
+               int rc;
+               rc = pf_af_hook(ifp, mppn, &m, AF_INET, FALSE);
+               if (rc != 0) {
+                       if (packetlist == m0) {
+                               packetlist = m;
+                               mppn = NULL;
+                       }
+                       if (m != NULL) {
+                               m0 = m;
+                               /* Next packet in the chain */
+                               goto loopit;
+                       } else if (packetlist != NULL) {
+                               /* No more packet; send down the chain */
+                               goto sendchain;
+                       }
+                       /* Nothing left; we're done */
+                       goto done;
+               }
+               m0 = m;
+               ip = mtod(m, struct ip *);
+               pkt_dst = ip->ip_dst;
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+       }
+#endif /* PF */
         /*
          * Force IP TTL to 255 following draft-ietf-zeroconf-ipv4-linklocal.txt
          */
@@ -608,33 +1006,56 @@ sendit:
                }
         }
 
-injectit:
        if (!didfilter && !TAILQ_EMPTY(&ipv4_filters)) {
                struct ipfilter *filter;
                int seen = (inject_filter_ref == 0);
-               
-               lck_mtx_unlock(ip_mutex);
+               ipf_pktopts.ippo_flags &= ~IPPOF_MCAST_OPTS;
+
+               /* Check that a TSO frame isn't passed to a filter.
+                * This could happen if a filter is inserted while
+                * TCP is sending the TSO packet.
+                */
+               if (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) {
+                       error = EMSGSIZE;
+                       goto bad;
+               }
+
                ipf_ref();
+               
+               /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
+               HTONS(ip->ip_len);
+               HTONS(ip->ip_off);
+#endif
+
                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                        if (seen == 0) {
                                if ((struct ipfilter *)inject_filter_ref == filter)
                                        seen = 1;
                        } else if (filter->ipf_filter.ipf_output) {
                                errno_t result;
-                               result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, 0);
+                               result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, ippo);
                                if (result == EJUSTRETURN) {
                                        ipf_unref();
                                        goto done;
                                }
                                if (result != 0) {
                                        ipf_unref();
-                                       lck_mtx_lock(ip_mutex);
                                        goto bad;
                                }
                        }
                }
+               
+               /* set back to host byte order */
+               ip = mtod(m, struct ip *);
+
+#if BYTE_ORDER != BIG_ENDIAN
+               NTOHS(ip->ip_len);
+               NTOHS(ip->ip_off);
+#endif
+
                ipf_unref();
-               lck_mtx_lock(ip_mutex);
        }
 
 #if IPSEC
@@ -645,7 +1066,6 @@ injectit:
 
        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
 
-       lck_mtx_lock(sadb_mutex);
 
        /* get SP for this packet */
        if (so == NULL)
@@ -654,9 +1074,8 @@ injectit:
                sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
 
        if (sp == NULL) {
-               ipsecstat.out_inval++;
+               IPSEC_STAT_INCREMENT(ipsecstat.out_inval);              
                KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
-               lck_mtx_unlock(sadb_mutex);
                goto bad;
        }
 
@@ -665,19 +1084,18 @@ injectit:
        /* check policy */
        switch (sp->policy) {
        case IPSEC_POLICY_DISCARD:
+       case IPSEC_POLICY_GENERATE:
                /*
                 * This packet is just discarded.
                 */
-               ipsecstat.out_polvio++;
+               IPSEC_STAT_INCREMENT(ipsecstat.out_polvio);
                KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 1,0,0,0,0);
-               lck_mtx_unlock(sadb_mutex);
                goto bad;
 
        case IPSEC_POLICY_BYPASS:
        case IPSEC_POLICY_NONE:
                /* no need to do IPsec. */
                KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 2,0,0,0,0);
-               lck_mtx_unlock(sadb_mutex);
                goto skip_ipsec;
        
        case IPSEC_POLICY_IPSEC:
@@ -685,7 +1103,6 @@ injectit:
                        /* acquire a policy */
                        error = key_spdacquire(sp);
                        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 3,0,0,0,0);
-                       lck_mtx_unlock(sadb_mutex);
                        goto bad;
                }
                break;
@@ -716,13 +1133,17 @@ injectit:
                m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
 
+
+#if BYTE_ORDER != BIG_ENDIAN
        HTONS(ip->ip_len);
        HTONS(ip->ip_off);
+#endif
+
+       DTRACE_IP6(send, struct mbuf *, m, struct inpcb *, NULL,
+               struct ip *, ip, struct ifnet *, ifp,
+               struct ip *, ip, struct ip6_hdr *, NULL);
 
-       lck_mtx_unlock(ip_mutex);
        error = ipsec4_output(&state, sp, flags);
-       lck_mtx_unlock(sadb_mutex);
-       lck_mtx_lock(ip_mutex);
     
        m0 = m = state.m;
        
@@ -771,66 +1192,105 @@ injectit:
        hlen = ip->ip_hl << 2;
 #endif
        /* Check that there wasn't a route change and src is still valid */
-
-       if (ro->ro_rt->generation_id != route_generation) {
-               if (ifa_foraddr(ip->ip_src.s_addr) == 0 && ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0)) {
-                       error = EADDRNOTAVAIL;
-                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 5,0,0,0,0);
+       if (ro->ro_rt != NULL && ro->ro_rt->generation_id != route_generation) {
+               if ((src_ia = ifa_foraddr(ip->ip_src.s_addr)) == NULL &&
+                   ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0)) {
+                       error = EADDRNOTAVAIL;
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                           5,0,0,0,0);
                        goto bad;
                }
                rtfree(ro->ro_rt);
                ro->ro_rt = NULL;
+               if (src_ia != NULL)
+                       IFA_REMREF(&src_ia->ia_ifa);
        }
 
        if (ro->ro_rt == NULL) {
                if ((flags & IP_ROUTETOIF) == 0) {
-                       printf("ip_output: "
-                               "can't update route after IPsec processing\n");
-                       error = EHOSTUNREACH;   /*XXX*/ 
-                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 6,0,0,0,0);
+                       printf("ip_output: can't update route after "
+                           "IPsec processing\n");
+                       error = EHOSTUNREACH;   /*XXX*/
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                           6,0,0,0,0);
                        goto bad;
                }
        } else {
                if (ia)
-                       ifafree(&ia->ia_ifa);
+                       IFA_REMREF(&ia->ia_ifa);
+               RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
-               if (ia)
-                       ifaref(&ia->ia_ifa);
+               if (ia) {
+                       /* Become a regular mutex */
+                       RT_CONVERT_LOCK(ro->ro_rt);
+                       IFA_ADDREF(&ia->ia_ifa);
+               }
                ifp = ro->ro_rt->rt_ifp;
+               RT_UNLOCK(ro->ro_rt);
        }
 
        /* make it flipped, again. */
+
+#if BYTE_ORDER != BIG_ENDIAN
        NTOHS(ip->ip_len);
        NTOHS(ip->ip_off);
+#endif
+       
        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 7,0xff,0xff,0xff,0xff);
        
        /* Pass to filters again */
        if (!TAILQ_EMPTY(&ipv4_filters)) {
                struct ipfilter *filter;
                
-               lck_mtx_unlock(ip_mutex);
+               ipf_pktopts.ippo_flags &= ~IPPOF_MCAST_OPTS;
+
+               /* Check that a TSO frame isn't passed to a filter.
+                * This could happen if a filter is inserted while
+                * TCP is sending the TSO packet.
+                */
+               if (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) {
+                       error = EMSGSIZE;
+                       goto bad;
+               }
+
                ipf_ref();
+               
+               /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
+               HTONS(ip->ip_len);
+               HTONS(ip->ip_off);
+#endif
+
                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                        if (filter->ipf_filter.ipf_output) {
                                errno_t result;
-                               result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, 0);
+                               result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, ippo);
                                if (result == EJUSTRETURN) {
                                        ipf_unref();
                                        goto done;
                                }
                                if (result != 0) {
                                        ipf_unref();
-                                       lck_mtx_lock(ip_mutex);
                                        goto bad;
                                }
                        }
                }
+               
+               /* set back to host byte order */
+               ip = mtod(m, struct ip *);
+
+#if BYTE_ORDER != BIG_ENDIAN
+               NTOHS(ip->ip_len);
+               NTOHS(ip->ip_off);
+#endif
+
                ipf_unref();
-               lck_mtx_lock(ip_mutex);
        }
 skip_ipsec:
 #endif /*IPSEC*/
 
+#if IPFIREWALL
        /*
         * IpHack's section.
         * - Xlate: translate packet's addr/port (NAT).
@@ -842,7 +1302,6 @@ skip_ipsec:
                struct  mbuf    *m1 = m;
 
                if ((error = (*fr_checkp)(ip, hlen, ifp, 1, &m1)) || !m1) {
-                       lck_mtx_unlock(ip_mutex);
                        goto done;
                }
                ip = mtod(m0 = m = m1, struct ip *);
@@ -858,7 +1317,6 @@ skip_ipsec:
                args.m = m;
                args.next_hop = dst;
                args.oif = ifp;
-               lck_mtx_unlock(ip_mutex);
                off = ip_fw_chk_ptr(&args);
                m = args.m;
                dst = args.next_hop;
@@ -885,31 +1343,32 @@ skip_ipsec:
                        goto done ;
                }
                ip = mtod(m, struct ip *);
+               
                if (off == 0 && dst == old) {/* common case */
-                       lck_mtx_lock(ip_mutex);
                        goto pass ;
                }
 #if DUMMYNET
                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG) != 0) {
-                    /*
-                     * pass the pkt to dummynet. Need to include
-                     * pipe number, m, ifp, ro, dst because these are
-                     * not recomputed in the next pass.
-                     * All other parameters have been already used and
-                     * so they are not needed anymore. 
-                     * XXX note: if the ifp or ro entry are deleted
-                     * while a pkt is in dummynet, we are in trouble!
-                     */ 
-                   args.ro = ro;
-                   args.dst = dst;
-                   args.flags = flags;
-
-                   error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
-                               &args);
-                   goto done;
+                       /*
+                        * pass the pkt to dummynet. Need to include
+                        * pipe number, m, ifp, ro, dst because these are
+                        * not recomputed in the next pass.
+                        * All other parameters have been already used and
+                        * so they are not needed anymore.
+                        * XXX note: if the ifp or ro entry are deleted
+                        * while a pkt is in dummynet, we are in trouble!
+                        */
+                       args.ro = ro;
+                       args.dst = dst;
+                       args.flags = flags;
+                       if (flags & IP_OUTARGS)
+                               args.ipoa = ipoa;
+
+                       error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
+                           &args);
+                       goto done;
                }
 #endif /* DUMMYNET */
-               lck_mtx_lock(ip_mutex);
 #if IPDIVERT
                if (off != 0 && (off & IP_FW_PORT_DYNT_FLAG) == 0) {
                        struct mbuf *clone = NULL;
@@ -928,8 +1387,11 @@ skip_ipsec:
                        }
 
                        /* Restore packet header fields to original values */
+
+#if BYTE_ORDER != BIG_ENDIAN
                        HTONS(ip->ip_len);
                        HTONS(ip->ip_off);
+#endif
 
                        /* Deliver packet to divert input routine */
                        divert_packet(m, 0, off & 0xffff, args.divert_rule);
@@ -940,7 +1402,6 @@ skip_ipsec:
                                ip = mtod(m, struct ip *);
                                goto pass;
                        }
-                       lck_mtx_unlock(ip_mutex);
                        goto done;
                }
 #endif
@@ -979,35 +1440,42 @@ skip_ipsec:
                         * as the packet runs through ip_input() as
                         * it is done through a ISR.
                         */
+                       lck_rw_lock_shared(in_ifaddr_rwlock);
                        TAILQ_FOREACH(ia_fw, &in_ifaddrhead, ia_link) {
                                /*
                                 * If the addr to forward to is one
                                 * of ours, we pretend to
                                 * be the destination for this packet.
                                 */
+                               IFA_LOCK_SPIN(&ia_fw->ia_ifa);
                                if (IA_SIN(ia_fw)->sin_addr.s_addr ==
-                                                dst->sin_addr.s_addr)
+                                   dst->sin_addr.s_addr) {
+                                       IFA_UNLOCK(&ia_fw->ia_ifa);
                                        break;
+                               }
+                               IFA_UNLOCK(&ia_fw->ia_ifa);
                        }
-                       if (ia) {
+                       lck_rw_done(in_ifaddr_rwlock);
+                       if (ia_fw) {
                                /* tell ip_input "dont filter" */
                                struct m_tag            *fwd_tag;
                                struct ip_fwd_tag       *ipfwd_tag;
-                               
-                               fwd_tag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD,
-                                               sizeof(struct sockaddr_in), M_NOWAIT);
+
+                               fwd_tag = m_tag_create(KERNEL_MODULE_TAG_ID,
+                                   KERNEL_TAG_TYPE_IPFORWARD,
+                                   sizeof (*ipfwd_tag), M_NOWAIT, m);
                                if (fwd_tag == NULL) {
                                        error = ENOBUFS;
                                        goto bad;
                                }
-                               
+
                                ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
                                ipfwd_tag->next_hop = args.next_hop;
 
                                m_tag_prepend(m, fwd_tag);
 
                                if (m->m_pkthdr.rcvif == NULL)
-                                       m->m_pkthdr.rcvif = ifunit("lo0");
+                                       m->m_pkthdr.rcvif = lo_ifp;
                                if ((~IF_HWASSIST_CSUM_FLAGS(m->m_pkthdr.rcvif->if_hwassist) & 
                                                m->m_pkthdr.csum_flags) == 0) {
                                        if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
@@ -1024,10 +1492,11 @@ skip_ipsec:
                                        m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
                                        ip->ip_sum = in_cksum(m, hlen);
                                }
+
+#if BYTE_ORDER != BIG_ENDIAN
                                HTONS(ip->ip_len);
                                HTONS(ip->ip_off);
-                               
-                               lck_mtx_unlock(ip_mutex);
+#endif                         
                                
                                /*  we need to call dlil_output to run filters
                                 *      and resync to avoid recursion loops.
@@ -1048,25 +1517,35 @@ skip_ipsec:
                         */
                        bcopy(dst, &ro_fwd->ro_dst, sizeof(*dst));
 
-                       ro_fwd->ro_rt = 0;
+                       ro_fwd->ro_rt = NULL;
                        rtalloc_ign(ro_fwd, RTF_PRCLONING);
 
-                       if (ro_fwd->ro_rt == 0) {
-                               ipstat.ips_noroute++;
+                       if (ro_fwd->ro_rt == NULL) {
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = EHOSTUNREACH;
                                goto bad;
                        }
 
+                       RT_LOCK_SPIN(ro_fwd->ro_rt);
                        ia_fw = ifatoia(ro_fwd->ro_rt->rt_ifa);
+                       if (ia_fw != NULL) {
+                               /* Become a regular mutex */
+                               RT_CONVERT_LOCK(ro_fwd->ro_rt);
+                               IFA_ADDREF(&ia_fw->ia_ifa);
+                       }
                        ifp = ro_fwd->ro_rt->rt_ifp;
                        ro_fwd->ro_rt->rt_use++;
                        if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
                                dst = (struct sockaddr_in *)ro_fwd->ro_rt->rt_gateway;
-                       if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
+                       if (ro_fwd->ro_rt->rt_flags & RTF_HOST) {
                                isbroadcast =
                                    (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
-                       else
+                       } else {
+                               /* Become a regular mutex */
+                               RT_CONVERT_LOCK(ro_fwd->ro_rt);
                                isbroadcast = in_broadcast(dst->sin_addr, ifp);
+                       }
+                       RT_UNLOCK(ro_fwd->ro_rt);
                        rtfree(ro->ro_rt);
                        ro->ro_rt = ro_fwd->ro_rt;
                        dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
@@ -1076,8 +1555,14 @@ skip_ipsec:
                         * which would have been gotten from the-then
                         * interface, do it again, from the new one.
                         */
-                       if (fwd_rewrite_src)
-                               ip->ip_src = IA_SIN(ia_fw)->sin_addr;
+                       if (ia_fw != NULL) {
+                               if (fwd_rewrite_src) {
+                                       IFA_LOCK_SPIN(&ia_fw->ia_ifa);
+                                       ip->ip_src = IA_SIN(ia_fw)->sin_addr;
+                                       IFA_UNLOCK(&ia_fw->ia_ifa);
+                               }
+                               IFA_REMREF(&ia_fw->ia_ifa);
+                       }
                        goto pass ;
                }
 #endif /* IPFIREWALL_FORWARD */
@@ -1087,17 +1572,17 @@ skip_ipsec:
                  */
                m_freem(m);
                error = EACCES; /* not sure this is the right error msg */
-               lck_mtx_unlock(ip_mutex);
                goto done;
        }
 
 pass:
+#endif /* IPFIREWALL */
 #if __APPLE__
        /* Do not allow loopback address to wind up on a wire */
        if ((ifp->if_flags & IFF_LOOPBACK) == 0 &&
                 ((ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
                  (ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET)) {
-               ipstat.ips_badaddr++;
+               OSAddAtomic(1, &ipstat.ips_badaddr);
                m_freem(m);
                /* 
                 * Do not simply drop the packet just like a firewall -- we want the 
@@ -1107,11 +1592,12 @@ pass:
                 * loopback as the source address.
                 */
                error = ENETUNREACH;
-               lck_mtx_unlock(ip_mutex);
                goto done;
        }
 #endif
        m->m_pkthdr.csum_flags |= CSUM_IP;
+       tso =  (ifp->if_hwassist & IFNET_TSO_IPV4) && (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4);
+                    
        sw_csum = m->m_pkthdr.csum_flags 
                & ~IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist);
 
@@ -1135,6 +1621,9 @@ pass:
                        /* let the software handle any UDP or TCP checksums */
                        sw_csum |= (CSUM_DELAY_DATA & m->m_pkthdr.csum_flags);
                }
+       } else if (apple_hwcksum_tx == 0) {
+               sw_csum |= (CSUM_DELAY_DATA | CSUM_DELAY_IP) &
+                   m->m_pkthdr.csum_flags;
        }
        
        if (sw_csum & CSUM_DELAY_DATA) {
@@ -1142,17 +1631,29 @@ pass:
                sw_csum &= ~CSUM_DELAY_DATA;
                m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
-       
-       m->m_pkthdr.csum_flags &= IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist);
+
+       if (apple_hwcksum_tx != 0) {
+               m->m_pkthdr.csum_flags &=
+                   IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist);
+       } else {
+               m->m_pkthdr.csum_flags = 0;
+       }
 
        /*
         * If small enough for interface, or the interface will take
         * care of the fragmentation for us, can just send directly.
         */
-       if ((u_short)ip->ip_len <= ifp->if_mtu ||
+       if ((u_short)ip->ip_len <= ifp->if_mtu || tso ||
            ifp->if_hwassist & CSUM_FRAGMENT) {
+               if (tso) 
+                       m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
+                       
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(ip->ip_len);
                HTONS(ip->ip_off);
+#endif
+               
                ip->ip_sum = 0;
                if (sw_csum & CSUM_DELAY_IP) {
                        ip->ip_sum = in_cksum(m, hlen);
@@ -1172,21 +1673,29 @@ pass:
                        ipsec_delaux(m);
 #endif
                if (packetchain == 0) {
-                       lck_mtx_unlock(ip_mutex);
-                       error = dlil_output(ifp, PF_INET, m, (void *) ro->ro_rt,
-                                   (struct sockaddr *)dst, 0);
-                       goto done;      
+                       if (ro->ro_rt && nstat_collect)
+                               nstat_route_tx(ro->ro_rt, 1, m->m_pkthdr.len, 0);
+                       error = ifnet_output(ifp, PF_INET, m, ro->ro_rt,
+                           (struct sockaddr *)dst);
+                       goto done;
                }
                else { /* packet chaining allows us to reuse the route for all packets */
+                       bytecnt += m->m_pkthdr.len;
+                       mppn = &m->m_nextpkt;
                        m = m->m_nextpkt;
                        if (m == NULL) {
+#if PF
+sendchain:
+#endif /* PF */
                                if (pktcnt > ip_maxchainsent)
                                        ip_maxchainsent = pktcnt;
+                               if (ro->ro_rt && nstat_collect)
+                                       nstat_route_tx(ro->ro_rt, pktcnt, bytecnt, 0);
                                //send
-                               lck_mtx_unlock(ip_mutex);
-                               error = dlil_output_list(ifp, PF_INET, packetlist, (void *) ro->ro_rt,
-                                       (struct sockaddr *)dst, 0);
+                               error = ifnet_output(ifp, PF_INET, packetlist,
+                                   ro->ro_rt, (struct sockaddr *)dst);
                                pktcnt = 0;
+                               bytecnt = 0;
                                goto done;
        
                        }
@@ -1199,7 +1708,9 @@ pass:
         * Too large for interface; fragment if possible.
         * Must be able to put at least 8 bytes per fragment.
         */
-       if (ip->ip_off & IP_DF) {
+
+       if (ip->ip_off & IP_DF  || (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) ||
+               pktcnt > 0) {
                error = EMSGSIZE;
                /*
                 * This case can happen if the user changed the MTU
@@ -1208,20 +1719,107 @@ pass:
                 * them, there is no way for one to update all its
                 * routes when the MTU is changed.
                 */
-               if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST))
-                   && !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU)
-                   && (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
-                       ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
+               if (ro->ro_rt) {
+                       RT_LOCK_SPIN(ro->ro_rt);
+                       if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST))
+                           && !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU)
+                           && (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
+                               ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
+                       }
+                       RT_UNLOCK(ro->ro_rt);
+               }
+               if (pktcnt > 0) {
+                       m0 = packetlist;
                }
-               ipstat.ips_cantfrag++;
+               OSAddAtomic(1, &ipstat.ips_cantfrag);
                goto bad;
        }
-       len = (ifp->if_mtu - hlen) &~ 7;
-       if (len < 8) {
-               error = EMSGSIZE;
+
+       error = ip_fragment(m, ifp, ifp->if_mtu, sw_csum);
+       if (error != 0) {
+               m0 = m = NULL;
                goto bad;
        }
 
+       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
+                    ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+       for (m = m0; m; m = m0) {
+               m0 = m->m_nextpkt;
+               m->m_nextpkt = 0;
+#if IPSEC
+               /* clean ipsec history once it goes out of the node */
+               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0)
+                       ipsec_delaux(m);
+#endif
+               if (error == 0) {
+#ifndef __APPLE__
+                       /* Record statistics for this interface address. */
+                       if (ia != NULL) {
+                               ia->ia_ifa.if_opackets++;
+                               ia->ia_ifa.if_obytes += m->m_pkthdr.len;
+                       }
+#endif
+                       if ((packetchain != 0)  && (pktcnt > 0))
+                               panic("ip_output: mix of packet in packetlist is wrong=%p", packetlist);
+                       if (ro->ro_rt && nstat_collect)
+                               nstat_route_tx(ro->ro_rt, 1, m->m_pkthdr.len, 0);
+                       error = ifnet_output(ifp, PF_INET, m, ro->ro_rt,
+                           (struct sockaddr *)dst);
+               } else
+                       m_freem(m);
+       }
+
+       if (error == 0)
+               OSAddAtomic(1, &ipstat.ips_fragmented);
+
+done:
+       if (ia) {
+               IFA_REMREF(&ia->ia_ifa);
+               ia = NULL;
+       }
+#if IPSEC
+       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
+       if (ro == &iproute && ro->ro_rt) {
+               rtfree(ro->ro_rt);
+               ro->ro_rt = NULL;
+       }
+       if (sp != NULL) {
+               KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
+                       printf("DP ip_output call free SP:%x\n", sp));
+               key_freesp(sp, KEY_SADB_UNLOCKED);
+       }
+       }
+#endif /* IPSEC */
+
+       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error,0,0,0,0);
+       return (error);
+bad:
+       m_freem(m0);
+       goto done;
+}
+
+int
+ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
+{
+       struct ip *ip, *mhip;
+       int len, hlen, mhlen, firstlen, off, error = 0;
+       struct mbuf **mnext = &m->m_nextpkt, *m0;
+       int nfrags = 1;
+
+       ip = mtod(m, struct ip *);
+#ifdef _IP_VHL
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+#else
+       hlen = ip->ip_hl << 2;
+#endif
+
+       firstlen = len = (mtu - hlen) &~ 7;
+       if (len < 8) {
+               m_freem(m);
+               return (EMSGSIZE);
+       }
+
        /*
         * if the interface will not calculate checksums on
         * fragmented packets, then do it here.
@@ -1229,19 +1827,9 @@ pass:
        if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
            (ifp->if_hwassist & CSUM_IP_FRAGS) == 0) {
                in_delayed_cksum(m);
-               if (m == NULL) {
-                       lck_mtx_unlock(ip_mutex);
-                       return(ENOMEM);
-               }
                m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
 
-
-    {
-       int mhlen, firstlen = len;
-       struct mbuf **mnext = &m->m_nextpkt;
-       int nfrags = 1;
-
        /*
         * Loop through length of segment after first fragment,
         * make new header and copy data of each part and link onto chain.
@@ -1249,10 +1837,10 @@ pass:
        m0 = m;
        mhlen = sizeof (struct ip);
        for (off = hlen + len; off < (u_short)ip->ip_len; off += len) {
-               MGETHDR(m, M_DONTWAIT, MT_HEADER);
+               MGETHDR(m, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
                if (m == 0) {
                        error = ENOBUFS;
-                       ipstat.ips_odropped++;
+                       OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
                }
                m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
@@ -1276,14 +1864,21 @@ pass:
                if (m->m_next == 0) {
                        (void) m_free(m);
                        error = ENOBUFS;        /* ??? */
-                       ipstat.ips_odropped++;
+                       OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
                }
                m->m_pkthdr.len = mhlen + len;
                m->m_pkthdr.rcvif = 0;
                m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
                m->m_pkthdr.socket_id = m0->m_pkthdr.socket_id;
+#if CONFIG_MACF_NET
+               mac_netinet_fragment(m0, m);
+#endif
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(mhip->ip_off);
+#endif
+
                mhip->ip_sum = 0;
                if (sw_csum & CSUM_DELAY_IP) {
                        mhip->ip_sum = in_cksum(m, mhlen);
@@ -1292,7 +1887,7 @@ pass:
                mnext = &m->m_nextpkt;
                nfrags++;
        }
-       ipstat.ips_ofragments += nfrags;
+       OSAddAtomic(nfrags, &ipstat.ips_ofragments);
 
        /* set first/last markers for fragment chain */
        m->m_flags |= M_LASTFRAG;
@@ -1308,96 +1903,69 @@ pass:
        m->m_pkthdr.len = hlen + firstlen;
        ip->ip_len = htons((u_short)m->m_pkthdr.len);
        ip->ip_off |= IP_MF;
+
+#if BYTE_ORDER != BIG_ENDIAN
        HTONS(ip->ip_off);
+#endif
+       
        ip->ip_sum = 0;
        if (sw_csum & CSUM_DELAY_IP) {
                ip->ip_sum = in_cksum(m, hlen);
        }
 sendorfree:
+       if (error)
+               m_freem_list(m0);
 
-       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
-                    ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
-
-       lck_mtx_unlock(ip_mutex);
-       for (m = m0; m; m = m0) {
-               m0 = m->m_nextpkt;
-               m->m_nextpkt = 0;
-#if IPSEC
-               /* clean ipsec history once it goes out of the node */
-               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0)
-                       ipsec_delaux(m);
-#endif
-               if (error == 0) {
-#ifndef __APPLE__
-                       /* Record statistics for this interface address. */
-                       if (ia != NULL) {
-                               ia->ia_ifa.if_opackets++;
-                               ia->ia_ifa.if_obytes += m->m_pkthdr.len;
-                       }
-#endif
-                   if ((packetchain != 0)  && (pktcnt > 0))    
-                               panic("ip_output: mix of packet in packetlist is wrong=%x", packetlist);
-                   error = dlil_output(ifp, PF_INET, m, (void *) ro->ro_rt,
-                                       (struct sockaddr *)dst, 0);
-               } else
-                       m_freem(m);
-       }
+       return (error);
+}
 
-       if (error == 0)
-               ipstat.ips_fragmented++;
-    }
-done:
-       if (ia) {
-               ifafree(&ia->ia_ifa);
-               ia = NULL;
-       }
-#if IPSEC
-       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-       if (ro == &iproute && ro->ro_rt) {
-               rtfree(ro->ro_rt);
-               ro->ro_rt = NULL;
-       }
-       if (sp != NULL) {
-               KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
-                       printf("DP ip_output call free SP:%x\n", sp));
-               lck_mtx_lock(sadb_mutex);
-               key_freesp(sp);
-               lck_mtx_unlock(sadb_mutex);
-       }
+static void
+ip_out_cksum_stats(int proto, u_int32_t len)
+{
+       switch (proto) {
+       case IPPROTO_TCP:
+               tcp_out_cksum_stats(len);
+               break;
+       case IPPROTO_UDP:
+               udp_out_cksum_stats(len);
+               break;
+       default:
+               /* keep only TCP or UDP stats for now */
+               break;
        }
-#endif /* IPSEC */
-
-       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error,0,0,0,0);
-       return (error);
-bad:
-       m_freem(m0);
-       lck_mtx_unlock(ip_mutex);
-       goto done;
 }
 
 void
-in_delayed_cksum_offset(struct mbuf *m, int ip_offset)
+in_delayed_cksum_offset(struct mbuf *m0, int ip_offset)
 {
        struct ip *ip;
-       u_short csum, offset;
-       
-       while (ip_offset > m->m_len) {
+       unsigned char buf[sizeof(struct ip)];
+       u_short csum, offset, ip_len;
+
+        /* Save copy of first mbuf pointer and the ip_offset before modifying */
+        struct mbuf *m = m0;
+        int ip_offset_copy = ip_offset;
+
+       while (ip_offset >= m->m_len) {
                ip_offset -= m->m_len;
                m = m->m_next;
-               if (m) {
+               if (m == NULL) {
                        printf("in_delayed_cksum_withoffset failed - ip_offset wasn't in the packet\n");
                        return;
                }
        }
        
+       /* Sometimes the IP header is not contiguous, yes this can happen! */
        if (ip_offset + sizeof(struct ip) > m->m_len) {
+#if DEBUG              
                printf("delayed m_pullup, m->len: %d  off: %d\n",
                        m->m_len, ip_offset);
-               /*
-                * XXX
-                * this shouldn't happen
-                */
-               m = m_pullup(m, ip_offset + sizeof(struct ip));
+#endif
+               m_copydata(m, ip_offset, sizeof(struct ip), (caddr_t) buf);
+               
+               ip = (struct ip *)buf;
+       } else {
+               ip = (struct ip*)(m->m_data + ip_offset);
        }
        
        /* Gross */
@@ -1406,36 +1974,60 @@ in_delayed_cksum_offset(struct mbuf *m, int ip_offset)
                m->m_data += ip_offset;
        }
        
-       ip = mtod(m, struct ip*);
        offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
-       csum = in_cksum_skip(m, ip->ip_len, offset);
-       if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
+
+       /*
+        * We could be in the context of an IP or interface filter; in the
+        * former case, ip_len would be in host (correct) order while for
+        * the latter it would be in network order.  Because of this, we
+        * attempt to interpret the length field by comparing it against
+        * the actual packet length.  If the comparison fails, byte swap
+        * the length and check again.  If it still fails, then the packet
+        * is bogus and we give up.
+        */
+       ip_len = ip->ip_len;
+       if (ip_len != (m0->m_pkthdr.len - ip_offset_copy)) {
+               ip_len = SWAP16(ip_len);
+               if (ip_len != (m0->m_pkthdr.len - ip_offset_copy)) {
+                       printf("in_delayed_cksum_offset: ip_len %d (%d) "
+                           "doesn't match actual length %d\n", ip->ip_len,
+                           ip_len, (m0->m_pkthdr.len - ip_offset_copy));
+                       return;
+               }
+       }
+
+       csum = in_cksum_skip(m, ip_len, offset);
+
+       /* Update stats */
+       ip_out_cksum_stats(ip->ip_p, ip_len - offset);
+
+       if (m0->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
                csum = 0xffff;
-       offset += m->m_pkthdr.csum_data & 0xFFFF;        /* checksum offset */
-       
+       offset += m0->m_pkthdr.csum_data & 0xFFFF;        /* checksum offset */
+
        /* Gross */
        if (ip_offset) {
                if (M_LEADINGSPACE(m) < ip_offset)
-                       panic("in_delayed_cksum_withoffset - chain modified!\n");
+                       panic("in_delayed_cksum_offset - chain modified!\n");
                m->m_len += ip_offset;
                m->m_data -= ip_offset;
        }
 
-       if (offset > ip->ip_len) /* bogus offset */
+       if (offset > ip_len) /* bogus offset */
                return;
 
+       /* Insert the checksum in the existing chain */
        if (offset + ip_offset + sizeof(u_short) > m->m_len) {
-               printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
+               char tmp[2];
+               
+#if DEBUG
+               printf("delayed m_copyback, m->len: %d  off: %d  p: %d\n",
                    m->m_len, offset + ip_offset, ip->ip_p);
-               /*
-                * XXX
-                * this shouldn't happen, but if it does, the
-                * correct behavior may be to insert the checksum
-                * in the existing chain instead of rearranging it.
-                */
-               m = m_pullup(m, offset + ip_offset + sizeof(u_short));
-       }
-       *(u_short *)(m->m_data + offset + ip_offset) = csum;
+#endif
+               *(u_short *)tmp = csum;
+               m_copyback(m, offset + ip_offset, 2, tmp);
+       } else
+               *(u_short *)(m->m_data + offset + ip_offset) = csum;
 }
 
 void
@@ -1449,24 +2041,37 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
 {
        struct ip* ip = NULL;
        int hlen = 0;
+       unsigned char buf[sizeof(struct ip)];
+       int swapped = 0;
+
+        /* Save copy of first mbuf pointer and the ip_offset before modifying */
+        struct mbuf* m0 = m;
+        size_t ip_offset_copy = ip_offset;
        
-       while (ip_offset > m->m_len) {
+       while (ip_offset >= m->m_len) {
                ip_offset -= m->m_len;
                m = m->m_next;
-               if (m) {
+               if (m == NULL) {
                        printf("in_cksum_offset failed - ip_offset wasn't in the packet\n");
                        return;
                }
        }
        
+       /* Sometimes the IP header is not contiguous, yes this can happen! */
        if (ip_offset + sizeof(struct ip) > m->m_len) {
-               printf("in_cksum_offset - delayed m_pullup, m->len: %d  off: %d\n",
+
+#if DEBUG
+               printf("in_cksum_offset - delayed m_pullup, m->len: %d  off: %lu\n",
                        m->m_len, ip_offset);
-               /*
-                * XXX
-                * this shouldn't happen
-                */
-               m = m_pullup(m, ip_offset + sizeof(struct ip));
+#endif 
+               m_copydata(m, ip_offset, sizeof(struct ip), (caddr_t) buf);
+
+               ip = (struct ip *)buf;
+               ip->ip_sum = 0;
+               m_copyback(m, ip_offset + offsetof(struct ip, ip_sum), 2, (caddr_t)&ip->ip_sum);
+       } else {
+               ip = (struct ip*)(m->m_data + ip_offset);
+               ip->ip_sum = 0;
        }
        
        /* Gross */
@@ -1475,17 +2080,38 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
                m->m_data += ip_offset;
        }
 
-       ip = mtod(m, struct ip*);
-
 #ifdef _IP_VHL
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 #else
        hlen = ip->ip_hl << 2;
 #endif
-       
+       /*
+        * We could be in the context of an IP or interface filter; in the
+        * former case, ip_len would be in host order while for the latter
+        * it would be in network (correct) order.  Because of this, we
+        * attempt to interpret the length field by comparing it against
+        * the actual packet length.  If the comparison fails, byte swap
+        * the length and check again.  If it still fails, then the packet
+        * is bogus and we give up.
+        */
+       if (ntohs(ip->ip_len) != (m0->m_pkthdr.len - ip_offset_copy)) {
+               ip->ip_len = SWAP16(ip->ip_len);
+               swapped = 1;
+               if (ntohs(ip->ip_len) != (m0->m_pkthdr.len - ip_offset_copy)) {
+                       ip->ip_len = SWAP16(ip->ip_len);
+                       printf("in_cksum_offset: ip_len %d (%d) "
+                           "doesn't match actual length %lu\n",
+                           ip->ip_len, SWAP16(ip->ip_len),
+                           (m0->m_pkthdr.len - ip_offset_copy));
+                       return;
+               }
+       }
+
        ip->ip_sum = 0;
        ip->ip_sum = in_cksum(m, hlen);
-       
+       if (swapped)
+               ip->ip_len = SWAP16(ip->ip_len);
+
        /* Gross */
        if (ip_offset) {
                if (M_LEADINGSPACE(m) < ip_offset)
@@ -1493,6 +2119,18 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
                m->m_len += ip_offset;
                m->m_data -= ip_offset;
        }
+
+       /* Insert the checksum in the existing chain if IP header not contiguous */
+       if (ip_offset + sizeof(struct ip) > m->m_len) {
+               char tmp[2];
+
+#if DEBUG
+               printf("in_cksum_offset m_copyback, m->len: %u  off: %lu  p: %d\n",
+                   m->m_len, ip_offset + offsetof(struct ip, ip_sum), ip->ip_p);
+#endif
+               *(u_short *)tmp = ip->ip_sum;
+               m_copyback(m, ip_offset + offsetof(struct ip, ip_sum), 2, tmp);
+       }
 }
 
 /*
@@ -1519,10 +2157,13 @@ ip_insertoptions(m, opt, phlen)
        if (p->ipopt_dst.s_addr)
                ip->ip_dst = p->ipopt_dst;
        if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
-               MGETHDR(n, M_DONTWAIT, MT_HEADER);
+               MGETHDR(n, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
                if (n == 0)
                        return (m);
                n->m_pkthdr.rcvif = 0;
+#if CONFIG_MACF_NET
+               mac_mbuf_label_copy(m, n);
+#endif
                n->m_pkthdr.len = m->m_pkthdr.len + optlen;
                m->m_len -= sizeof(struct ip);
                m->m_data += sizeof(struct ip);
@@ -1620,7 +2261,8 @@ ip_ctloutput(so, sopt)
                                error = EMSGSIZE;
                                break;
                        }
-                       MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_HEADER);
+                       MGET(m, sopt->sopt_p != kernproc ? M_WAIT : M_DONTWAIT,
+                           MT_HEADER);
                        if (m == 0) {
                                error = ENOBUFS;
                                break;
@@ -1645,6 +2287,7 @@ ip_ctloutput(so, sopt)
 #if defined(NFAITH) && NFAITH > 0
                case IP_FAITH:
 #endif
+               case IP_RECVPKTINFO:
                        error = sooptcopyin(sopt, &optval, sizeof optval,
                                            sizeof optval);
                        if (error)
@@ -1689,17 +2332,99 @@ ip_ctloutput(so, sopt)
                                OPTSET(INP_FAITH);
                                break;
 #endif
+                       case IP_RECVPKTINFO:
+                               OPTSET(INP_PKTINFO);
+                               break;
                        }
                        break;
 #undef OPTSET
 
+#if CONFIG_FORCE_OUT_IFP
+               /*
+                * Apple private interface, similar to IP_BOUND_IF, except
+                * that the parameter is a NULL-terminated string containing
+                * the name of the network interface; an emptry string means
+                * unbind.  Applications are encouraged to use IP_BOUND_IF
+                * instead, as that is the current "official" API.
+                */
+               case IP_FORCE_OUT_IFP: {
+                       char ifname[IFNAMSIZ];
+                       unsigned int ifscope;
+
+                       /* This option is settable only for IPv4 */
+                       if (!(inp->inp_vflag & INP_IPV4)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       /* Verify interface name parameter is sane */
+                       if (sopt->sopt_valsize > sizeof(ifname)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       /* Copy the interface name */
+                       if (sopt->sopt_valsize != 0) {
+                               error = sooptcopyin(sopt, ifname,
+                                   sizeof (ifname), sopt->sopt_valsize);
+                               if (error)
+                                       break;
+                       }
+
+                       if (sopt->sopt_valsize == 0 || ifname[0] == '\0') {
+                               /* Unbind this socket from any interface */
+                               ifscope = IFSCOPE_NONE;
+                       } else {
+                               ifnet_t ifp;
+
+                               /* Verify name is NULL terminated */
+                               if (ifname[sopt->sopt_valsize - 1] != '\0') {
+                                       error = EINVAL;
+                                       break;
+                               }
+
+                               /* Bail out if given bogus interface name */
+                               if (ifnet_find_by_name(ifname, &ifp) != 0) {
+                                       error = ENXIO;
+                                       break;
+                               }
+
+                               /* Bind this socket to this interface */
+                               ifscope = ifp->if_index;
+
+                               /*
+                                * Won't actually free; since we don't release
+                                * this later, we should do it now.
+                                */
+                               ifnet_release(ifp);
+                       }
+                       inp_bindif(inp, ifscope);
+               }
+               break;
+#endif
+               /*
+                * Multicast socket options are processed by the in_mcast
+                * module.
+                */
                case IP_MULTICAST_IF:
+               case IP_MULTICAST_IFINDEX:
                case IP_MULTICAST_VIF:
                case IP_MULTICAST_TTL:
                case IP_MULTICAST_LOOP:
                case IP_ADD_MEMBERSHIP:
                case IP_DROP_MEMBERSHIP:
-                       error = ip_setmoptions(sopt, &inp->inp_moptions);
+               case IP_ADD_SOURCE_MEMBERSHIP:
+               case IP_DROP_SOURCE_MEMBERSHIP:
+               case IP_BLOCK_SOURCE:
+               case IP_UNBLOCK_SOURCE:
+               case IP_MSFILTER:
+               case MCAST_JOIN_GROUP:
+               case MCAST_LEAVE_GROUP:
+               case MCAST_JOIN_SOURCE_GROUP:
+               case MCAST_LEAVE_SOURCE_GROUP:
+               case MCAST_BLOCK_SOURCE:
+               case MCAST_UNBLOCK_SOURCE:
+                       error = inp_setmoptions(inp, sopt);
                        break;
 
                case IP_PORTRANGE:
@@ -1739,29 +2464,97 @@ ip_ctloutput(so, sopt)
                        struct mbuf *m;
                        int optname;
 
-                        if (sopt->sopt_valsize > MCLBYTES) {
-                                error = EMSGSIZE;
-                                break;
-                        }
                        if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
                                break;
                        if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
                                break;
-                       priv = (sopt->sopt_p != NULL &&
-                               proc_suser(sopt->sopt_p) != 0) ? 0 : 1;
+                       priv = (proc_suser(sopt->sopt_p) == 0);
                        if (m) {
                                req = mtod(m, caddr_t);
                                len = m->m_len;
                        }
                        optname = sopt->sopt_name;
-                       lck_mtx_lock(sadb_mutex);
                        error = ipsec4_set_policy(inp, optname, req, len, priv);
-                       lck_mtx_unlock(sadb_mutex);
                        m_freem(m);
                        break;
                }
 #endif /*IPSEC*/
 
+#if TRAFFIC_MGT
+               case IP_TRAFFIC_MGT_BACKGROUND:
+               {
+                       unsigned        background = 0;
+                       error = sooptcopyin(sopt, &background, sizeof(background), sizeof(background));
+                       if (error) 
+                               break;
+
+                       if (background) {
+                               socket_set_traffic_mgt_flags_locked(so,
+                                   TRAFFIC_MGT_SO_BACKGROUND);
+                       } else {
+                               socket_clear_traffic_mgt_flags_locked(so,
+                                   TRAFFIC_MGT_SO_BACKGROUND);
+                       }
+
+                       break;
+               }
+#endif /* TRAFFIC_MGT */
+
+               /*
+                * On a multihomed system, scoped routing can be used to
+                * restrict the source interface used for sending packets.
+                * The socket option IP_BOUND_IF binds a particular AF_INET
+                * socket to an interface such that data sent on the socket
+                * is restricted to that interface.  This is unlike the
+                * SO_DONTROUTE option where the routing table is bypassed;
+                * therefore it allows for a greater flexibility and control
+                * over the system behavior, and does not place any restriction
+                * on the destination address type (e.g.  unicast, multicast,
+                * or broadcast if applicable) or whether or not the host is
+                * directly reachable.  Note that in the multicast transmit
+                * case, IP_MULTICAST_{IF,IFINDEX} takes precedence over
+                * IP_BOUND_IF, since the former practically bypasses the
+                * routing table; in this case, IP_BOUND_IF sets the default
+                * interface used for sending multicast packets in the absence
+                * of an explicit multicast transmit interface.
+                */
+               case IP_BOUND_IF:
+                       /* This option is settable only for IPv4 */
+                       if (!(inp->inp_vflag & INP_IPV4)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       error = sooptcopyin(sopt, &optval, sizeof (optval),
+                           sizeof (optval));
+
+                       if (error)
+                               break;
+
+                       inp_bindif(inp, optval);
+                       break;
+
+               case IP_NO_IFT_CELLULAR:
+                       /* This option is settable only for IPv4 */
+                       if (!(inp->inp_vflag & INP_IPV4)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       error = sooptcopyin(sopt, &optval, sizeof (optval),
+                           sizeof (optval));
+
+                       if (error)
+                               break;
+
+                       error = inp_nocellular(inp, optval);
+                       break;
+
+               case IP_OUT_IF:
+                       /* This option is not settable */
+                       error = EINVAL;
+                       break;
+
                default:
                        error = ENOPROTOOPT;
                        break;
@@ -1792,6 +2585,7 @@ ip_ctloutput(so, sopt)
 #if defined(NFAITH) && NFAITH > 0
                case IP_FAITH:
 #endif
+               case IP_RECVPKTINFO:
                        switch (sopt->sopt_name) {
 
                        case IP_TOS:
@@ -1838,17 +2632,20 @@ ip_ctloutput(so, sopt)
                                optval = OPTBIT(INP_FAITH);
                                break;
 #endif
+                       case IP_RECVPKTINFO:
+                               optval = OPTBIT(INP_PKTINFO);
+                               break;
                        }
                        error = sooptcopyout(sopt, &optval, sizeof optval);
                        break;
 
                case IP_MULTICAST_IF:
+               case IP_MULTICAST_IFINDEX:
                case IP_MULTICAST_VIF:
                case IP_MULTICAST_TTL:
                case IP_MULTICAST_LOOP:
-               case IP_ADD_MEMBERSHIP:
-               case IP_DROP_MEMBERSHIP:
-                       error = ip_getmoptions(sopt, inp->inp_moptions);
+               case IP_MSFILTER:
+                       error = inp_getmoptions(inp, sopt);
                        break;
 
 #if IPSEC
@@ -1862,9 +2659,7 @@ ip_ctloutput(so, sopt)
                                req = mtod(m, caddr_t);
                                len = m->m_len;
                        }
-                       lck_mtx_lock(sadb_mutex);
                        error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
-                       lck_mtx_unlock(sadb_mutex);
                        if (error == 0)
                                error = soopt_mcopyout(sopt, m); /* XXX */
                        if (error == 0)
@@ -1873,13 +2668,38 @@ ip_ctloutput(so, sopt)
                }
 #endif /*IPSEC*/
 
-               default:
-                       error = ENOPROTOOPT;
+#if TRAFFIC_MGT
+               case IP_TRAFFIC_MGT_BACKGROUND:
+               {
+                       unsigned        background = (so->so_traffic_mgt_flags &  TRAFFIC_MGT_SO_BACKGROUND);
+                       return (sooptcopyout(sopt, &background, sizeof(background)));
                        break;
                }
-               break;
-       }
-       return (error);
+#endif /* TRAFFIC_MGT */
+
+               case IP_BOUND_IF:
+                       if (inp->inp_flags & INP_BOUND_IF)
+                               optval = inp->inp_boundif;
+                       error = sooptcopyout(sopt, &optval, sizeof (optval));
+                       break;
+
+               case IP_NO_IFT_CELLULAR:
+                       optval = (inp->inp_flags & INP_NO_IFT_CELLULAR) ? 1 : 0;
+                       error = sooptcopyout(sopt, &optval, sizeof (optval));
+                       break;
+
+               case IP_OUT_IF:
+                       optval = inp->inp_last_outif;
+                       error = sooptcopyout(sopt, &optval, sizeof (optval));
+                       break;
+
+               default:
+                       error = ENOPROTOOPT;
+                       break;
+               }
+               break;
+       }
+       return (error);
 }
 
 /*
@@ -1888,10 +2708,10 @@ ip_ctloutput(so, sopt)
  * with destination address if source routed.
  */
 static int
-ip_pcbopts(optname, pcbopt, m)
-       int optname;
-       struct mbuf **pcbopt;
-       register struct mbuf *m;
+ip_pcbopts(
+       __unused int optname,
+       struct mbuf **pcbopt,
+       register struct mbuf *m)
 {
        register int cnt, optlen;
        register u_char *cp;
@@ -1987,460 +2807,138 @@ bad:
        return (EINVAL);
 }
 
-/*
- * XXX
- * The whole multicast option thing needs to be re-thought.
- * Several of these options are equally applicable to non-multicast
- * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
- * standard option (IP_TTL).
- */
-
-/*
- * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
- */
-static struct ifnet *
-ip_multicast_if(a, ifindexp)
-       struct in_addr *a;
-       int *ifindexp;
+void
+ip_moptions_init(void)
 {
-       int ifindex;
-       struct ifnet *ifp;
+       PE_parse_boot_argn("ifa_debug", &imo_debug, sizeof (imo_debug));
 
-       if (ifindexp)
-               *ifindexp = 0;
-       if (ntohl(a->s_addr) >> 24 == 0) {
-               ifindex = ntohl(a->s_addr) & 0xffffff;
-               ifnet_head_lock_shared();
-               if (ifindex < 0 || if_index < ifindex) {
-                       ifnet_head_done();
-                       return NULL;
-               }
-               ifp = ifindex2ifnet[ifindex];
-               ifnet_head_done();
-               if (ifindexp)
-                       *ifindexp = ifindex;
-       } else {
-               INADDR_TO_IFP(*a, ifp);
+       imo_size = (imo_debug == 0) ? sizeof (struct ip_moptions) :
+           sizeof (struct ip_moptions_dbg);
+
+       imo_zone = zinit(imo_size, IMO_ZONE_MAX * imo_size, 0,
+           IMO_ZONE_NAME);
+       if (imo_zone == NULL) {
+               panic("%s: failed allocating %s", __func__, IMO_ZONE_NAME);
+               /* NOTREACHED */
        }
-       return ifp;
+       zone_change(imo_zone, Z_EXPAND, TRUE);
 }
 
-/*
- * Set the IP multicast options in response to user setsockopt().
- */
-static int
-ip_setmoptions(sopt, imop)
-       struct sockopt *sopt;
-       struct ip_moptions **imop;
+void
+imo_addref(struct ip_moptions *imo, int locked)
 {
-       int error = 0;
-       int i;
-       struct in_addr addr;
-       struct ip_mreq mreq;
-       struct ifnet *ifp = NULL;
-       struct ip_moptions *imo = *imop;
-       int ifindex;
+       if (!locked)
+               IMO_LOCK(imo);
+       else
+               IMO_LOCK_ASSERT_HELD(imo);
 
-       if (imo == NULL) {
-               /*
-                * No multicast option buffer attached to the pcb;
-                * allocate one and initialize to default values.
-                */
-               error = ip_createmoptions(imop);
-               if (error != 0)
-                       return error;
-               imo = *imop;
+       if (++imo->imo_refcnt == 0) {
+               panic("%s: imo %p wraparound refcnt\n", __func__, imo);
+               /* NOTREACHED */
+       } else if (imo->imo_trace != NULL) {
+               (*imo->imo_trace)(imo, TRUE);
        }
 
-       switch (sopt->sopt_name) {
-       /* store an index number for the vif you wanna use in the send */
-       case IP_MULTICAST_VIF:
-               if (legal_vif_num == 0) {
-                       error = EOPNOTSUPP;
-                       break;
-               }
-               error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
-               if (error)
-                       break;
-               if (!legal_vif_num(i) && (i != -1)) {
-                       error = EINVAL;
-                       break;
-               }
-               imo->imo_multicast_vif = i;
-               break;
-
-       case IP_MULTICAST_IF:
-               /*
-                * Select the interface for outgoing multicast packets.
-                */
-               error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
-               if (error)
-                       break;
-               /*
-                * INADDR_ANY is used to remove a previous selection.
-                * When no interface is selected, a default one is
-                * chosen every time a multicast packet is sent.
-                */
-               if (addr.s_addr == INADDR_ANY) {
-                       imo->imo_multicast_ifp = NULL;
-                       break;
-               }
-               /*
-                * The selected interface is identified by its local
-                * IP address.  Find the interface and confirm that
-                * it supports multicasting.
-                */
-               ifp = ip_multicast_if(&addr, &ifindex);
-               if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
-                       error = EADDRNOTAVAIL;
-                       break;
-               }
-               imo->imo_multicast_ifp = ifp;
-               if (ifindex)
-                       imo->imo_multicast_addr = addr;
-               else
-                       imo->imo_multicast_addr.s_addr = INADDR_ANY;
-               break;
-
-       case IP_MULTICAST_TTL:
-               /*
-                * Set the IP time-to-live for outgoing multicast packets.
-                * The original multicast API required a char argument,
-                * which is inconsistent with the rest of the socket API.
-                * We allow either a char or an int.
-                */
-               if (sopt->sopt_valsize == 1) {
-                       u_char ttl;
-                       error = sooptcopyin(sopt, &ttl, 1, 1);
-                       if (error)
-                               break;
-                       imo->imo_multicast_ttl = ttl;
-               } else {
-                       u_int ttl;
-                       error = sooptcopyin(sopt, &ttl, sizeof ttl, 
-                                           sizeof ttl);
-                       if (error)
-                               break;
-                       if (ttl > 255)
-                               error = EINVAL;
-                       else
-                               imo->imo_multicast_ttl = ttl;
-               }
-               break;
-
-       case IP_MULTICAST_LOOP:
-               /*
-                * Set the loopback flag for outgoing multicast packets.
-                * Must be zero or one.  The original multicast API required a
-                * char argument, which is inconsistent with the rest
-                * of the socket API.  We allow either a char or an int.
-                */
-               if (sopt->sopt_valsize == 1) {
-                       u_char loop;
-                       error = sooptcopyin(sopt, &loop, 1, 1);
-                       if (error)
-                               break;
-                       imo->imo_multicast_loop = !!loop;
-               } else {
-                       u_int loop;
-                       error = sooptcopyin(sopt, &loop, sizeof loop,
-                                           sizeof loop);
-                       if (error)
-                               break;
-                       imo->imo_multicast_loop = !!loop;
-               }
-               break;
-
-       case IP_ADD_MEMBERSHIP:
-               /*
-                * Add a multicast group membership.
-                * Group must be a valid IP multicast address.
-                */
-               error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
-               if (error)
-                       break;
-               
-               error = ip_addmembership(imo, &mreq);
-               break;
+       if (!locked)
+               IMO_UNLOCK(imo);
+}
 
-       case IP_DROP_MEMBERSHIP:
-               /*
-                * Drop a multicast group membership.
-                * Group must be a valid IP multicast address.
-                */
-               error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
-               if (error)
-                       break;
-               
-               error = ip_dropmembership(imo, &mreq);
-               break;
+void
+imo_remref(struct ip_moptions *imo)
+{
+       int i;
 
-       default:
-               error = EOPNOTSUPP;
-               break;
+       IMO_LOCK(imo);
+       if (imo->imo_refcnt == 0) {
+               panic("%s: imo %p negative refcnt", __func__, imo);
+               /* NOTREACHED */
+       } else if (imo->imo_trace != NULL) {
+               (*imo->imo_trace)(imo, FALSE);
        }
 
-       /*
-        * If all options have default values, no need to keep the mbuf.
-        */
-       if (imo->imo_multicast_ifp == NULL &&
-           imo->imo_multicast_vif == -1 &&
-           imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
-           imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
-           imo->imo_num_memberships == 0) {
-               FREE(*imop, M_IPMOPTS);
-               *imop = NULL;
+       --imo->imo_refcnt;
+       if (imo->imo_refcnt > 0) {
+               IMO_UNLOCK(imo);
+               return;
        }
 
-       return (error);
-}
+       for (i = 0; i < imo->imo_num_memberships; ++i) {
+               struct in_mfilter *imf;
 
-/*
- * Set the IP multicast options in response to user setsockopt().
- */
-__private_extern__ int
-ip_createmoptions(
-       struct ip_moptions **imop)
-{
-       struct ip_moptions *imo;
-       imo = (struct ip_moptions*) _MALLOC(sizeof(*imo), M_IPMOPTS,
-               M_WAITOK);
-
-       if (imo == NULL)
-               return (ENOBUFS);
-       *imop = imo;
-       imo->imo_multicast_ifp = NULL;
-       imo->imo_multicast_addr.s_addr = INADDR_ANY;
-       imo->imo_multicast_vif = -1;
-       imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
-       imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
-       imo->imo_num_memberships = 0;
-       
-       return 0;
-}
+               imf = imo->imo_mfilters ? &imo->imo_mfilters[i] : NULL;
+               if (imf != NULL)
+                       imf_leave(imf);
 
-/*
- * Add membership to an IPv4 multicast.
- */
-__private_extern__ int
-ip_addmembership(
-       struct ip_moptions *imo,
-       struct ip_mreq *mreq)
-{
-       struct route ro;
-       struct sockaddr_in *dst;
-       struct ifnet *ifp = NULL;
-       int error = 0;
-       int i;
-       
-       if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) {
-               error = EINVAL;
-               return error;
-       }
-       /*
-        * If no interface address was provided, use the interface of
-        * the route to the given multicast address.
-        */
-       if (mreq->imr_interface.s_addr == INADDR_ANY) {
-               bzero((caddr_t)&ro, sizeof(ro));
-               dst = (struct sockaddr_in *)&ro.ro_dst;
-               dst->sin_len = sizeof(*dst);
-               dst->sin_family = AF_INET;
-               dst->sin_addr = mreq->imr_multiaddr;
-               rtalloc(&ro);
-               if (ro.ro_rt != NULL) {
-                       ifp = ro.ro_rt->rt_ifp;
-                       rtfree(ro.ro_rt);
-               }
-               else {
-                       /* If there's no default route, try using loopback */
-                       mreq->imr_interface.s_addr = INADDR_LOOPBACK;
-               }
-       }
-       
-       if (ifp == NULL) {
-               ifp = ip_multicast_if(&mreq->imr_interface, NULL);
-       }
+               (void) in_leavegroup(imo->imo_membership[i], imf);
 
-       /*
-        * See if we found an interface, and confirm that it
-        * supports multicast.
-        */
-       if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
-               error = EADDRNOTAVAIL;
-               return error;
-       }
-       /*
-        * See if the membership already exists or if all the
-        * membership slots are full.
-        */
-       for (i = 0; i < imo->imo_num_memberships; ++i) {
-               if (imo->imo_membership[i]->inm_ifp == ifp &&
-                       imo->imo_membership[i]->inm_addr.s_addr
-                                       == mreq->imr_multiaddr.s_addr)
-                       break;
-       }
-       if (i < imo->imo_num_memberships) {
-               error = EADDRINUSE;
-               return error;
+               if (imf != NULL)
+                       imf_purge(imf);
+
+               INM_REMREF(imo->imo_membership[i]);
+               imo->imo_membership[i] = NULL;
        }
-       if (i == IP_MAX_MEMBERSHIPS) {
-               error = ETOOMANYREFS;
-               return error;
+       imo->imo_num_memberships = 0;
+       if (imo->imo_mfilters != NULL) {
+               FREE(imo->imo_mfilters, M_INMFILTER);
+               imo->imo_mfilters = NULL;
        }
-       /*
-        * Everything looks good; add a new record to the multicast
-        * address list for the given interface.
-        */
-       if ((imo->imo_membership[i] =
-               in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) {
-               error = ENOBUFS;
-               return error;
+       if (imo->imo_membership != NULL) {
+               FREE(imo->imo_membership, M_IPMOPTS);
+               imo->imo_membership = NULL;
        }
-       ++imo->imo_num_memberships;
-       
-       return error;
-}
+       IMO_UNLOCK(imo);
 
-/*
- * Drop membership of an IPv4 multicast.
- */
-__private_extern__ int
-ip_dropmembership(
-       struct ip_moptions *imo,
-       struct ip_mreq *mreq)
-{
-       int error = 0;
-       struct ifnet* ifp = NULL;
-       int i;
-       
-       if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) {
-               error = EINVAL;
-               return error;
-       }
+       lck_mtx_destroy(&imo->imo_lock, ifa_mtx_grp);
 
-       /*
-        * If an interface address was specified, get a pointer
-        * to its ifnet structure.
-        */
-       if (mreq->imr_interface.s_addr == INADDR_ANY)
-               ifp = NULL;
-       else {
-               ifp = ip_multicast_if(&mreq->imr_interface, NULL);
-               if (ifp == NULL) {
-                       error = EADDRNOTAVAIL;
-                       return error;
-               }
+       if (!(imo->imo_debug & IFD_ALLOC)) {
+               panic("%s: imo %p cannot be freed", __func__, imo);
+               /* NOTREACHED */
        }
-       /*
-        * Find the membership in the membership array.
-        */
-       for (i = 0; i < imo->imo_num_memberships; ++i) {
-               if ((ifp == NULL ||
-                        imo->imo_membership[i]->inm_ifp == ifp) &&
-                        imo->imo_membership[i]->inm_addr.s_addr ==
-                        mreq->imr_multiaddr.s_addr)
-                       break;
-       }
-       if (i == imo->imo_num_memberships) {
-               error = EADDRNOTAVAIL;
-               return error;
-       }
-       /*
-        * Give up the multicast address record to which the
-        * membership points.
-        */
-       in_delmulti(&imo->imo_membership[i]);
-       /*
-        * Remove the gap in the membership array.
-        */
-       for (++i; i < imo->imo_num_memberships; ++i)
-               imo->imo_membership[i-1] = imo->imo_membership[i];
-       --imo->imo_num_memberships;
-       
-       return error;
+       zfree(imo_zone, imo);
 }
 
-/*
- * Return the IP multicast options in response to user getsockopt().
- */
-static int
-ip_getmoptions(sopt, imo)
-       struct sockopt *sopt;
-       register struct ip_moptions *imo;
+static void
+imo_trace(struct ip_moptions *imo, int refhold)
 {
-       struct in_addr addr;
-       struct in_ifaddr *ia;
-       int error, optval;
-       u_char coptval;
-
-       error = 0;
-       switch (sopt->sopt_name) {
-       case IP_MULTICAST_VIF: 
-               if (imo != NULL)
-                       optval = imo->imo_multicast_vif;
-               else
-                       optval = -1;
-               error = sooptcopyout(sopt, &optval, sizeof optval);
-               break;
-
-       case IP_MULTICAST_IF:
-               if (imo == NULL || imo->imo_multicast_ifp == NULL)
-                       addr.s_addr = INADDR_ANY;
-               else if (imo->imo_multicast_addr.s_addr) {
-                       /* return the value user has set */
-                       addr = imo->imo_multicast_addr;
-               } else {
-                       IFP_TO_IA(imo->imo_multicast_ifp, ia);
-                       addr.s_addr = (ia == NULL) ? INADDR_ANY
-                               : IA_SIN(ia)->sin_addr.s_addr;
-               }
-               error = sooptcopyout(sopt, &addr, sizeof addr);
-               break;
-
-       case IP_MULTICAST_TTL:
-               if (imo == 0)
-                       optval = coptval = IP_DEFAULT_MULTICAST_TTL;
-               else
-                       optval = coptval = imo->imo_multicast_ttl;
-               if (sopt->sopt_valsize == 1)
-                       error = sooptcopyout(sopt, &coptval, 1);
-               else
-                       error = sooptcopyout(sopt, &optval, sizeof optval);
-               break;
-
-       case IP_MULTICAST_LOOP:
-               if (imo == 0)
-                       optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
-               else
-                       optval = coptval = imo->imo_multicast_loop;
-               if (sopt->sopt_valsize == 1)
-                       error = sooptcopyout(sopt, &coptval, 1);
-               else
-                       error = sooptcopyout(sopt, &optval, sizeof optval);
-               break;
-
-       default:
-               error = ENOPROTOOPT;
-               break;
+       struct ip_moptions_dbg *imo_dbg = (struct ip_moptions_dbg *)imo;
+       ctrace_t *tr;
+       u_int32_t idx;
+       u_int16_t *cnt;
+
+       if (!(imo->imo_debug & IFD_DEBUG)) {
+               panic("%s: imo %p has no debug structure", __func__, imo);
+               /* NOTREACHED */
+       }
+       if (refhold) {
+               cnt = &imo_dbg->imo_refhold_cnt;
+               tr = imo_dbg->imo_refhold;
+       } else {
+               cnt = &imo_dbg->imo_refrele_cnt;
+               tr = imo_dbg->imo_refrele;
        }
-       return (error);
+
+       idx = atomic_add_16_ov(cnt, 1) % IMO_TRACE_HIST_SIZE;
+       ctrace_record(&tr[idx]);
 }
 
-/*
- * Discard the IP multicast options.
- */
-void
-ip_freemoptions(imo)
-       register struct ip_moptions *imo;
+struct ip_moptions *
+ip_allocmoptions(int how)
 {
-       register int i;
+       struct ip_moptions *imo;
 
+       imo = (how == M_WAITOK) ? zalloc(imo_zone) : zalloc_noblock(imo_zone);
        if (imo != NULL) {
-               for (i = 0; i < imo->imo_num_memberships; ++i)
-                       in_delmulti(&imo->imo_membership[i]);
-               FREE(imo, M_IPMOPTS);
+               bzero(imo, imo_size);
+               lck_mtx_init(&imo->imo_lock, ifa_mtx_grp, ifa_mtx_attr);
+               imo->imo_debug |= IFD_ALLOC;
+               if (imo_debug != 0) {
+                       imo->imo_debug |= IFD_DEBUG;
+                       imo->imo_trace = imo_trace;
+               }
+               IMO_ADDREF(imo);
        }
+
+       return (imo);
 }
 
 /*
@@ -2459,83 +2957,370 @@ ip_mloopback(ifp, m, dst, hlen)
 {
        register struct ip *ip;
        struct mbuf *copym;
+       int sw_csum = (apple_hwcksum_tx == 0);
 
        copym = m_copy(m, 0, M_COPYALL);
        if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
                copym = m_pullup(copym, hlen);
-       if (copym != NULL) {
-               /*
-                * We don't bother to fragment if the IP length is greater
-                * than the interface's MTU.  Can this possibly matter?
-                */
-               ip = mtod(copym, struct ip *);
-               HTONS(ip->ip_len);
-               HTONS(ip->ip_off);
-               ip->ip_sum = 0;
-               ip->ip_sum = in_cksum(copym, hlen);
-               /*
-                * NB:
-                * It's not clear whether there are any lingering
-                * reentrancy problems in other areas which might
-                * be exposed by using ip_input directly (in
-                * particular, everything which modifies the packet
-                * in-place).  Yet another option is using the
-                * protosw directly to deliver the looped back
-                * packet.  For the moment, we'll err on the side
-                * of safety by using if_simloop().
-                */
+
+       if (copym == NULL)
+               return;
+
+       /*
+        * We don't bother to fragment if the IP length is greater
+        * than the interface's MTU.  Can this possibly matter?
+        */
+       ip = mtod(copym, struct ip *);
+
+#if BYTE_ORDER != BIG_ENDIAN
+       HTONS(ip->ip_len);
+       HTONS(ip->ip_off);
+#endif
+       
+       ip->ip_sum = 0;
+       ip->ip_sum = in_cksum(copym, hlen);
+       /*
+        * NB:
+        * It's not clear whether there are any lingering
+        * reentrancy problems in other areas which might
+        * be exposed by using ip_input directly (in
+        * particular, everything which modifies the packet
+        * in-place).  Yet another option is using the
+        * protosw directly to deliver the looped back
+        * packet.  For the moment, we'll err on the side
+        * of safety by using if_simloop().
+        */
 #if 1 /* XXX */
-               if (dst->sin_family != AF_INET) {
-                       printf("ip_mloopback: bad address family %d\n",
-                                               dst->sin_family);
-                       dst->sin_family = AF_INET;
-               }
+       if (dst->sin_family != AF_INET) {
+               printf("ip_mloopback: bad address family %d\n",
+                                       dst->sin_family);
+               dst->sin_family = AF_INET;
+       }
 #endif
 
-
         /*
-        * Mark checksum as valid or calculate checksum for loopback.
-        * 
-        * This is done this way because we have to embed the ifp of
-        * the interface we will send the original copy of the packet
-        * out on in the mbuf. ip_input will check if_hwassist of the
-        * embedded ifp and ignore all csum_flags if if_hwassist is 0.
-        * The UDP checksum has not been calculated yet.
-        */
-        if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
-            if (IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist)) {
-                copym->m_pkthdr.csum_flags |=
-                    CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
-                    CSUM_IP_CHECKED | CSUM_IP_VALID;
-                copym->m_pkthdr.csum_data = 0xffff;
-            } else {
-               NTOHS(ip->ip_len);
-                in_delayed_cksum(copym);
-               HTONS(ip->ip_len);
-           }
+         * Mark checksum as valid or calculate checksum for loopback.
+         *
+         * This is done this way because we have to embed the ifp of
+         * the interface we will send the original copy of the packet
+         * out on in the mbuf. ip_input will check if_hwassist of the
+         * embedded ifp and ignore all csum_flags if if_hwassist is 0.
+         * The UDP checksum has not been calculated yet.
+         */
+        if (sw_csum || (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA)) {
+               if (!sw_csum && IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist)) {
+                       copym->m_pkthdr.csum_flags |=
+                           CSUM_DATA_VALID | CSUM_PSEUDO_HDR |
+                           CSUM_IP_CHECKED | CSUM_IP_VALID;
+                       copym->m_pkthdr.csum_data = 0xffff;
+               } else {
+
+#if BYTE_ORDER != BIG_ENDIAN
+                       NTOHS(ip->ip_len);
+#endif
+                       
+                       in_delayed_cksum(copym);
+
+#if BYTE_ORDER != BIG_ENDIAN
+                       HTONS(ip->ip_len);
+#endif
+               
+               }
         }
 
+       /*
+        * TedW: 
+        * We need to send all loopback traffic down to dlil in case 
+        * a filter has tapped-in.
+        */
+
+       /*
+        * Stuff the 'real' ifp into the pkthdr, to be used in matching
+        *  in ip_input(); we need the loopback ifp/dl_tag passed as args
+        *  to make the loopback driver compliant with the data link
+        *  requirements.
+        */
+       if (lo_ifp) {
+               copym->m_pkthdr.rcvif = ifp;
+               dlil_output(lo_ifp, PF_INET, copym, 0,
+                   (struct sockaddr *) dst, 0);
+       } else {
+               printf("Warning: ip_output call to dlil_find_dltag failed!\n");
+               m_freem(copym);
+       }
+}
+
+/*
+ * Given a source IP address (and route, if available), determine the best
+ * interface to send the packet from.  Checking for (and updating) the
+ * ROF_SRCIF_SELECTED flag in the pcb-supplied route placeholder is done
+ * without any locks based on the assumption that ip_output() is single-
+ * threaded per-pcb, i.e. for any given pcb there can only be one thread
+ * performing output at the IP layer.
+ *
+ * This routine is analogous to in6_selectroute() for IPv6.
+ */
+static struct ifaddr *
+in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
+{
+       struct ifaddr *ifa = NULL;
+       struct in_addr src = ip->ip_src;
+       struct in_addr dst = ip->ip_dst;
+       struct ifnet *rt_ifp;
+       char s_src[MAX_IPv4_STR_LEN], s_dst[MAX_IPv4_STR_LEN];
+
+       if (ip_select_srcif_debug) {
+               (void) inet_ntop(AF_INET, &src.s_addr, s_src, sizeof (s_src));
+               (void) inet_ntop(AF_INET, &dst.s_addr, s_dst, sizeof (s_dst));
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_LOCK(ro->ro_rt);
+
+       rt_ifp = (ro->ro_rt != NULL) ? ro->ro_rt->rt_ifp : NULL;
+
+       /*
+        * Given the source IP address, find a suitable source interface
+        * to use for transmission; if the caller has specified a scope,
+        * optimize the search by looking at the addresses only for that
+        * interface.  This is still suboptimal, however, as we need to
+        * traverse the per-interface list.
+        */
+       if (ifscope != IFSCOPE_NONE || ro->ro_rt != NULL) {
+               unsigned int scope = ifscope;
+
+               /*
+                * If no scope is specified and the route is stale (pointing
+                * to a defunct interface) use the current primary interface;
+                * this happens when switching between interfaces configured
+                * with the same IP address.  Otherwise pick up the scope
+                * information from the route; the ULP may have looked up a
+                * correct route and we just need to verify it here and mark
+                * it with the ROF_SRCIF_SELECTED flag below.
+                */
+               if (scope == IFSCOPE_NONE) {
+                       scope = rt_ifp->if_index;
+                       if (scope != get_primary_ifscope(AF_INET) &&
+                           ro->ro_rt->generation_id != route_generation)
+                               scope = get_primary_ifscope(AF_INET);
+               }
+
+               ifa = (struct ifaddr *)ifa_foraddr_scoped(src.s_addr, scope);
+
+               if (ifa == NULL && ip->ip_p != IPPROTO_UDP &&
+                   ip->ip_p != IPPROTO_TCP && ipforwarding) {
+                       /*
+                        * If forwarding is enabled, and if the packet isn't
+                        * TCP or UDP, check if the source address belongs
+                        * to one of our own interfaces; if so, demote the
+                        * interface scope and do a route lookup right below.
+                        */
+                       ifa = (struct ifaddr *)ifa_foraddr(src.s_addr);
+                       if (ifa != NULL) {
+                               IFA_REMREF(ifa);
+                               ifa = NULL;
+                               ifscope = IFSCOPE_NONE;
+                       }
+               }
+
+               if (ip_select_srcif_debug && ifa != NULL) {
+                       if (ro->ro_rt != NULL) {
+                               printf("%s->%s ifscope %d->%d ifa_if %s "
+                                   "ro_if %s\n", s_src, s_dst, ifscope,
+                                   scope, if_name(ifa->ifa_ifp),
+                                   if_name(rt_ifp));
+                       } else {
+                               printf("%s->%s ifscope %d->%d ifa_if %s\n",
+                                   s_src, s_dst, ifscope, scope,
+                                   if_name(ifa->ifa_ifp));
+                       }
+               }
+       }
+
+       /*
+        * Slow path; search for an interface having the corresponding source
+        * IP address if the scope was not specified by the caller, and:
+        *
+        *   1) There currently isn't any route, or,
+        *   2) The interface used by the route does not own that source
+        *      IP address; in this case, the route will get blown away
+        *      and we'll do a more specific scoped search using the newly
+        *      found interface.
+        */
+       if (ifa == NULL && ifscope == IFSCOPE_NONE) {
+               ifa = (struct ifaddr *)ifa_foraddr(src.s_addr);
 
                /*
-                * TedW: 
-                * We need to send all loopback traffic down to dlil in case 
-                * a filter has tapped-in.
+                * If we have the IP address, but not the route, we don't
+                * really know whether or not it belongs to the correct
+                * interface (it could be shared across multiple interfaces.)
+                * The only way to find out is to do a route lookup.
                 */
+               if (ifa != NULL && ro->ro_rt == NULL) {
+                       struct rtentry *rt;
+                       struct sockaddr_in sin;
+                       struct ifaddr *oifa = NULL;
+
+                       bzero(&sin, sizeof (sin));
+                       sin.sin_family = AF_INET;
+                       sin.sin_len = sizeof (sin);
+                       sin.sin_addr = dst;
+
+                       lck_mtx_lock(rnh_lock);
+                       if ((rt = rt_lookup(TRUE, (struct sockaddr *)&sin, NULL,
+                           rt_tables[AF_INET], IFSCOPE_NONE)) != NULL) {
+                               RT_LOCK(rt);
+                               /*
+                                * If the route uses a different interface,
+                                * use that one instead.  The IP address of
+                                * the ifaddr that we pick up here is not
+                                * relevant.
+                                */
+                               if (ifa->ifa_ifp != rt->rt_ifp) {
+                                       oifa = ifa;
+                                       ifa = rt->rt_ifa;
+                                       IFA_ADDREF(ifa);
+                                       RT_UNLOCK(rt);
+                               } else {
+                                       RT_UNLOCK(rt);
+                               }
+                               rtfree_locked(rt);
+                       }
+                       lck_mtx_unlock(rnh_lock);
+
+                       if (oifa != NULL) {
+                               struct ifaddr *iifa;
+
+                               /*
+                                * See if the interface pointed to by the
+                                * route is configured with the source IP
+                                * address of the packet.
+                                */
+                               iifa = (struct ifaddr *)ifa_foraddr_scoped(
+                                   src.s_addr, ifa->ifa_ifp->if_index);
+
+                               if (iifa != NULL) {
+                                       /*
+                                        * Found it; drop the original one
+                                        * as well as the route interface
+                                        * address, and use this instead.
+                                        */
+                                       IFA_REMREF(oifa);
+                                       IFA_REMREF(ifa);
+                                       ifa = iifa;
+                               } else if (!ipforwarding ||
+                                   (rt->rt_flags & RTF_GATEWAY)) {
+                                       /*
+                                        * This interface doesn't have that
+                                        * source IP address; drop the route
+                                        * interface address and just use the
+                                        * original one, and let the caller
+                                        * do a scoped route lookup.
+                                        */
+                                       IFA_REMREF(ifa);
+                                       ifa = oifa;
+                               } else {
+                                       /*
+                                        * Forwarding is enabled and the source
+                                        * address belongs to one of our own
+                                        * interfaces which isn't the outgoing
+                                        * interface, and we have a route, and
+                                        * the destination is on a network that
+                                        * is directly attached (onlink); drop
+                                        * the original one and use the route
+                                        * interface address instead.
+                                        */
+                                       IFA_REMREF(oifa);
+                               }
+                       }
+               } else if (ifa != NULL && ro->ro_rt != NULL &&
+                   !(ro->ro_rt->rt_flags & RTF_GATEWAY) &&
+                   ifa->ifa_ifp != ro->ro_rt->rt_ifp && ipforwarding) {
+                       /*
+                        * Forwarding is enabled and the source address belongs
+                        * to one of our own interfaces which isn't the same
+                        * as the interface used by the known route; drop the
+                        * original one and use the route interface address.
+                        */
+                       IFA_REMREF(ifa);
+                       ifa = ro->ro_rt->rt_ifa;
+                       IFA_ADDREF(ifa);
+               }
+
+               if (ip_select_srcif_debug && ifa != NULL) {
+                       printf("%s->%s ifscope %d ifa_if %s\n",
+                           s_src, s_dst, ifscope, if_name(ifa->ifa_ifp));
+               }
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_LOCK_ASSERT_HELD(ro->ro_rt);
+       /*
+        * If there is a non-loopback route with the wrong interface, or if
+        * there is no interface configured with such an address, blow it
+        * away.  Except for local/loopback, we look for one with a matching
+        * interface scope/index.
+        */
+       if (ro->ro_rt != NULL &&
+           (ifa == NULL || (ifa->ifa_ifp != rt_ifp && rt_ifp != lo_ifp) ||
+           !(ro->ro_rt->rt_flags & RTF_UP))) {
+               if (ip_select_srcif_debug) {
+                       if (ifa != NULL) {
+                               printf("%s->%s ifscope %d ro_if %s != "
+                                   "ifa_if %s (cached route cleared)\n",
+                                   s_src, s_dst, ifscope, if_name(rt_ifp),
+                                   if_name(ifa->ifa_ifp));
+                       } else {
+                               printf("%s->%s ifscope %d ro_if %s "
+                                   "(no ifa_if found)\n",
+                                   s_src, s_dst, ifscope, if_name(rt_ifp));
+                       }
+               }
+
+               RT_UNLOCK(ro->ro_rt);
+               rtfree(ro->ro_rt);
+               ro->ro_rt = NULL;
+               ro->ro_flags &= ~ROF_SRCIF_SELECTED;
 
                /*
-                * Stuff the 'real' ifp into the pkthdr, to be used in matching
-                *  in ip_input(); we need the loopback ifp/dl_tag passed as args
-                *  to make the loopback driver compliant with the data link
-                *  requirements.
+                * If the destination is IPv4 LLA and the route's interface
+                * doesn't match the source interface, then the source IP
+                * address is wrong; it most likely belongs to the primary
+                * interface associated with the IPv4 LL subnet.  Drop the
+                * packet rather than letting it go out and return an error
+                * to the ULP.  This actually applies not only to IPv4 LL
+                * but other shared subnets; for now we explicitly test only
+                * for the former case and save the latter for future.
                 */
-               if (lo_ifp) {
-                       copym->m_pkthdr.rcvif = ifp;
-                   dlil_output(lo_ifp, PF_INET, copym, 0, (struct sockaddr *) dst, 0);
-               } else {
-                   printf("Warning: ip_output call to dlil_find_dltag failed!\n");
-                   m_freem(copym);
+               if (IN_LINKLOCAL(ntohl(dst.s_addr)) &&
+                   !IN_LINKLOCAL(ntohl(src.s_addr)) && ifa != NULL) {
+                       IFA_REMREF(ifa);
+                       ifa = NULL;
                }
+       }
 
-/*             if_simloop(ifp, copym, (struct sockaddr *)dst, 0);*/
+       if (ip_select_srcif_debug && ifa == NULL) {
+               printf("%s->%s ifscope %d (neither ro_if/ifa_if found)\n",
+                   s_src, s_dst, ifscope);
        }
+
+       /*
+        * If there is a route, mark it accordingly.  If there isn't one,
+        * we'll get here again during the next transmit (possibly with a
+        * route) and the flag will get set at that point.  For IPv4 LLA
+        * destination, mark it only if the route has been fully resolved;
+        * otherwise we want to come back here again when the route points
+        * to the interface over which the ARP reply arrives on.
+        */
+       if (ro->ro_rt != NULL && (!IN_LINKLOCAL(ntohl(dst.s_addr)) ||
+           (ro->ro_rt->rt_gateway->sa_family == AF_LINK &&
+           SDL(ro->ro_rt->rt_gateway)->sdl_alen != 0))) {
+               ro->ro_flags |= ROF_SRCIF_SELECTED;
+               ro->ro_rt->generation_id = route_generation;
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_UNLOCK(ro->ro_rt);
+
+       return (ifa);
 }