]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/netinet/ip_output.c
xnu-4570.31.3.tar.gz
[apple/xnu.git] / bsd / netinet / ip_output.c
index c4530e9947830770c844f6b3b0ecd7557cd7ea8f..f5b51ac5251a76661d22467733c9cd2a2218578e 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2000-2011 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2017 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * 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,
@@ -22,7 +22,7 @@
  * 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_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
@@ -58,7 +58,6 @@
  * SUCH DAMAGE.
  *
  *     @(#)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
@@ -67,7 +66,7 @@
  * Version 2.0.
  */
 
-#define _IP_VHL
+#define        _IP_VHL
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <kern/locks.h>
 #include <sys/sysctl.h>
 #include <sys/mcache.h>
+#include <sys/kdebug.h>
 
 #include <machine/endian.h>
 #include <pexpert/pexpert.h>
+#include <mach/sdt.h>
+
+#include <libkern/OSAtomic.h>
+#include <libkern/OSByteOrder.h>
 
 #include <net/if.h>
 #include <net/if_dl.h>
@@ -90,6 +94,8 @@
 #include <net/route.h>
 #include <net/ntstat.h>
 #include <net/net_osdep.h>
+#include <net/dlil.h>
+#include <net/net_perf.h>
 
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_var.h>
 #include <netinet/ip_var.h>
-
 #include <netinet/kpi_ipfilter_var.h>
+#include <netinet/in_tclass.h>
 
 #if CONFIG_MACF_NET
 #include <security/mac_framework.h>
-#endif
+#endif /* CONFIG_MACF_NET */
 
-#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))
+#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)
 
 #if IPSEC
 #include <netinet6/ipsec.h>
 #if IPSEC_DEBUG
 #include <netkey/key_debug.h>
 #else
-#define        KEYDEBUG(lev,arg)
+#define        KEYDEBUG(lev, arg)
 #endif
-#endif /*IPSEC*/
+#endif /* IPSEC */
+
+#if NECP
+#include <net/necp.h>
+#endif /* NECP */
 
+#if IPFIREWALL
 #include <netinet/ip_fw.h>
+#if IPDIVERT
 #include <netinet/ip_divert.h>
-#include <mach/sdt.h>
+#endif /* IPDIVERT */
+#endif /* IPFIREWALL */
 
 #if DUMMYNET
 #include <netinet/ip_dummynet.h>
 #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)>>8)&0xFF,\
-                                                 (ntohl(a.s_addr))&0xFF);
-#endif
-
+#if IPFIREWALL_FORWARD && 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) >> 8) & 0xFF,                              \
+           (ntohl(a.s_addr)) & 0xFF);
+#endif /* IPFIREWALL_FORWARD && IPFIREWALL_FORWARD_DEBUG */
 
 u_short ip_id;
 
-static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
-static void    ip_mloopback(struct ifnet *, struct mbuf *,
-       struct sockaddr_in *, int);
-static int     ip_pcbopts(int, struct mbuf **, struct mbuf *);
-static void    imo_trace(struct ip_moptions *, int);
-
+static int sysctl_reset_ip_output_stats SYSCTL_HANDLER_ARGS;
+static int sysctl_ip_output_measure_bins SYSCTL_HANDLER_ARGS;
+static int sysctl_ip_output_getperf SYSCTL_HANDLER_ARGS;
 static void ip_out_cksum_stats(int, u_int32_t);
+static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
+static int ip_optcopy(struct ip *, struct ip *);
+static int ip_pcbopts(int, struct mbuf **, struct mbuf *);
+static void imo_trace(struct ip_moptions *, int);
+static void ip_mloopback(struct ifnet *, struct ifnet *, struct mbuf *,
+    struct sockaddr_in *, int);
 static struct ifaddr *in_selectsrcif(struct ip *, struct route *, unsigned int);
 
-int    ip_optcopy(struct ip *, struct ip *);
-void in_delayed_cksum_offset(struct mbuf *, int );
-void in_cksum_offset(struct mbuf* , size_t );
-
-extern int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **);
-
-extern struct protosw inetsw[];
-
 extern struct ip_linklocal_stat ip_linklocal_stat;
-extern lck_mtx_t *ip_mutex;
 
 /* temporary: for testing */
 #if IPSEC
 extern int ipsec_bypass;
 #endif
 
-static int     ip_maxchainsent = 0;
-SYSCTL_INT(_net_inet_ip, OID_AUTO, maxchainsent, CTLFLAG_RW | CTLFLAG_LOCKED,
-    &ip_maxchainsent, 0, "use dlil_output_list");
+static int ip_maxchainsent = 0;
+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");
+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");
+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");
+
+static int ip_output_measure = 0;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, output_perf,
+       CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+       &ip_output_measure, 0, sysctl_reset_ip_output_stats, "I",
+       "Do time measurement");
+
+static uint64_t ip_output_measure_bins = 0;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, output_perf_bins,
+       CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED, &ip_output_measure_bins, 0,
+       sysctl_ip_output_measure_bins, "I",
+       "bins for chaining performance data histogram");
+
+static net_perf_t net_perf;
+SYSCTL_PROC(_net_inet_ip, OID_AUTO, output_perf_data,
+       CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
+       0, 0, sysctl_ip_output_getperf, "S,net_perf",
+       "IP output performance data (struct net_perf, net/net_perf.h)");
+
+__private_extern__ int rfc6864 = 1;
+SYSCTL_INT(_net_inet_ip, OID_AUTO, rfc6864, CTLFLAG_RW | CTLFLAG_LOCKED,
+       &rfc6864, 0, "updated ip id field behavior");
 
 #define        IMO_TRACE_HIST_SIZE     32      /* size of trace history */
 
@@ -226,104 +250,128 @@ static struct zone *imo_zone;           /* zone for ip_moptions */
  * The mbuf opt, if present, will not be freed.
  */
 int
-ip_output(
-       struct mbuf *m0,
-       struct mbuf *opt,
-       struct route *ro,
-       int flags,
-       struct ip_moptions *imo,
-       struct ip_out_args *ipoa)
+ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro, int flags,
+    struct ip_moptions *imo, struct ip_out_args *ipoa)
 {
-       int error;
-       error = ip_output_list(m0, 0, opt, ro, flags, imo, ipoa);
-       return error;
+       return (ip_output_list(m0, 0, opt, ro, flags, imo, ipoa));
 }
 
 /*
- * 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]
+ * IP output.  The packet in mbuf chain m contains a skeletal IP
+ * header (with len, off, ttl, proto, tos, src, dst).
+ * The mbuf chain containing the packet will be freed.
+ * The mbuf opt, if present, will not be freed.
+ *
+ * Route ro MUST be non-NULL; if ro->ro_rt is valid, route lookup would be
+ * skipped and ro->ro_rt would be used.  Otherwise the result of route
+ * lookup is stored in ro->ro_rt.
  *
- * 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.
+ * In the IP forwarding case, the packet will arrive with options already
+ * inserted, so must have a NULL opt pointer.
  */
 int
-ip_output_list(
-       struct mbuf *m0,
-       int packetchain,
-       struct mbuf *opt,
-       struct route *ro,
-       int flags,
-       struct ip_moptions *imo,
-       struct ip_out_args *ipoa
-       )
+ip_output_list(struct mbuf *m0, int packetchain, struct mbuf *opt,
+    struct route *ro, int flags, struct ip_moptions *imo,
+    struct ip_out_args *ipoa)
 {
        struct ip *ip;
-       struct ifnet *ifp = NULL;
-       struct mbuf *m = m0, **mppn = NULL;
+       struct ifnet *ifp = NULL;               /* not refcnt'd */
+       struct mbuf *m = m0, *prevnxt = NULL, **mppn = &prevnxt;
        int hlen = sizeof (struct ip);
        int len = 0, error = 0;
        struct sockaddr_in *dst = 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;
+       struct ipf_pktopts *ippo = NULL;
+       ipfilter_t inject_filter_ref = NULL;
+       struct mbuf *packetlist;
+       uint32_t sw_csum, pktcnt = 0, scnt = 0, bytecnt = 0;
+       uint32_t packets_processed = 0;
+       unsigned int ifscope = IFSCOPE_NONE;
+       struct flowadv *adv = NULL;
+       struct timeval start_tv;
 #if IPSEC
-       struct ipsec_output_state ipsec_state;
-       struct route *ipsec_saved_route = NULL;
        struct socket *so = NULL;
        struct secpolicy *sp = NULL;
-#endif
-#if IPFIREWALL_FORWARD
-       int fwd_rewrite_src = 0;
-#endif
+#endif /* IPSEC */
+#if NECP
+       necp_kernel_policy_result necp_result = 0;
+       necp_kernel_policy_result_parameter necp_result_parameter;
+       necp_kernel_policy_id necp_matched_policy_id = 0;
+#endif /* NECP */
 #if IPFIREWALL
-       int off;
-       struct ip_fw_args args;
-       struct m_tag    *tag;
+       int ipfwoff;
        struct sockaddr_in *next_hop_from_ipfwd_tag = NULL;
-#endif
-       int didfilter = 0;
-       ipfilter_t inject_filter_ref = 0;
+#endif /* IPFIREWALL */
+#if IPFIREWALL || DUMMYNET
+       struct m_tag *tag;
+#endif /* IPFIREWALL || DUMMYNET */
 #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, 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);
-
+       struct {
 #if IPSEC
-       bzero(&ipsec_state, sizeof(ipsec_state));
+               struct ipsec_output_state ipsec_state;
 #endif /* IPSEC */
+#if NECP
+               struct route necp_route;
+#endif /* NECP */
+#if IPFIREWALL || DUMMYNET
+               struct ip_fw_args args;
+#endif /* IPFIREWALL || DUMMYNET */
+#if IPFIREWALL_FORWARD
+               struct route sro_fwd;
+#endif /* IPFIREWALL_FORWARD */
+#if DUMMYNET
+               struct route saved_route;
+#endif /* DUMMYNET */
+               struct ipf_pktopts ipf_pktopts;
+       } ipobz;
+#define        ipsec_state     ipobz.ipsec_state
+#define        necp_route      ipobz.necp_route
+#define        args            ipobz.args
+#define        sro_fwd         ipobz.sro_fwd
+#define        saved_route     ipobz.saved_route
+#define        ipf_pktopts     ipobz.ipf_pktopts
+       union {
+               struct {
+                       boolean_t select_srcif : 1;     /* set once */
+                       boolean_t srcbound : 1;         /* set once */
+                       boolean_t nocell : 1;           /* set once */
+                       boolean_t isbroadcast : 1;
+                       boolean_t didfilter : 1;
+                       boolean_t noexpensive : 1;      /* set once */
+                       boolean_t awdl_unrestricted : 1;        /* set once */
+#if IPFIREWALL_FORWARD
+                       boolean_t fwd_rewrite_src : 1;
+#endif /* IPFIREWALL_FORWARD */
+               };
+               uint32_t raw;
+       } ipobf = { .raw = 0 };
 
+/*
+ * Here we check for restrictions when sending frames.
+ * N.B.: IPv4 over internal co-processor interfaces is not allowed.
+ */
+#define        IP_CHECK_RESTRICTIONS(_ifp, _ipobf)                             \
+       (((_ipobf).nocell && IFNET_IS_CELLULAR(_ifp)) ||                \
+        ((_ipobf).noexpensive && IFNET_IS_EXPENSIVE(_ifp)) ||          \
+          (IFNET_IS_INTCOPROC(_ifp)) ||                                        \
+        (!(_ipobf).awdl_unrestricted && IFNET_IS_AWDL_RESTRICTED(_ifp)))
+
+       if (ip_output_measure)
+               net_perf_start_time(&net_perf, &start_tv);
+       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_START, 0, 0, 0, 0, 0);
+
+       VERIFY(m0->m_flags & M_PKTHDR);
        packetlist = m0;
-#if IPFIREWALL
-       args.next_hop = NULL;
-       args.eh = NULL;
-       args.rule = NULL;
-       args.divert_rule = 0;                   /* divert cookie */
-       args.ipoa = NULL;
 
+       /* zero out {ipsec_state, args, sro_fwd, saved_route, ipf_pktops} */
+       bzero(&ipobz, sizeof (ipobz));
+       ippo = &ipf_pktopts;
+
+#if IPFIREWALL || DUMMYNET
        if (SLIST_EMPTY(&m0->m_pkthdr.tags))
                goto ipfw_tags_done;
 
@@ -334,18 +382,21 @@ ip_output_list(
                struct dn_pkt_tag       *dn_tag;
 
                dn_tag = (struct dn_pkt_tag *)(tag+1);
-               args.rule = dn_tag->rule;
+               args.fwa_ipfw_rule = dn_tag->dn_ipfw_rule;
+               args.fwa_pf_rule = dn_tag->dn_pf_rule;
                opt = NULL;
-               saved_route = dn_tag->ro;
+               saved_route = dn_tag->dn_ro;
                ro = &saved_route;
 
                imo = NULL;
-               bcopy(&dn_tag->dn_dst, &dst_buf, sizeof(dst_buf));
+               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;
+               ifp = dn_tag->dn_ifp;
+               flags = dn_tag->dn_flags;
+               if ((dn_tag->dn_flags & IP_OUTARGS)) {
+                       saved_ipoa = dn_tag->dn_ipoa;
+                       ipoa = &saved_ipoa;
+               }
 
                m_tag_delete(m0, tag);
        }
@@ -357,65 +408,108 @@ ip_output_list(
                struct divert_tag       *div_tag;
 
                div_tag = (struct divert_tag *)(tag+1);
-               args.divert_rule = div_tag->cookie;
+               args.fwa_divert_rule = div_tag->cookie;
 
                m_tag_delete(m0, tag);
        }
 #endif /* IPDIVERT */
 
+#if IPFIREWALL
        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);
                next_hop_from_ipfwd_tag = ipfwd_tag->next_hop;
-               
+
                m_tag_delete(m0, tag);
        }
-ipfw_tags_done:
 #endif /* IPFIREWALL */
 
+ipfw_tags_done:
+#endif /* IPFIREWALL || DUMMYNET */
+
        m = m0;
+       m->m_pkthdr.pkt_flags &= ~(PKTF_LOOP|PKTF_IFAINFO);
 
-#if    DIAGNOSTIC
-       if ( !m || (m->m_flags & M_PKTHDR) != 0)
-               panic("ip_output no HDR");
-       if (!ro)
-               panic("ip_output no route, proto = %d",
-                     mtod(m, struct ip *)->ip_p);
-#endif
+#if IPSEC
+       if (ipsec_bypass == 0 && !(flags & IP_NOIPSEC)) {
+               /* If packet is bound to an interface, check bound policies */
+               if ((flags & IP_OUTARGS) && (ipoa != NULL) &&
+                       (ipoa->ipoa_flags & IPOAF_BOUND_IF) &&
+                       ipoa->ipoa_boundif != IFSCOPE_NONE) {
+                       if (ipsec4_getpolicybyinterface(m, IPSEC_DIR_OUTBOUND,
+                               &flags, ipoa, &sp) != 0)
+                               goto bad;
+               }
+       }
+#endif /* IPSEC */
 
-       bzero(&ipf_pktopts, sizeof(struct ipf_pktopts));
-       ippo = &ipf_pktopts;
+       VERIFY(ro != NULL);
 
-       /*
-        * 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);
+       if (flags & IP_OUTARGS) {
+               /*
+                * In the forwarding case, only the ifscope value is used,
+                * as source interface selection doesn't take place.
+                */
+               if ((ipobf.select_srcif = (!(flags & IP_FORWARDING) &&
+                   (ipoa->ipoa_flags & IPOAF_SELECT_SRCIF)))) {
+                       ipf_pktopts.ippo_flags |= IPPOF_SELECT_SRCIF;
+               }
+
+               if ((ipoa->ipoa_flags & IPOAF_BOUND_IF) &&
+                   ipoa->ipoa_boundif != IFSCOPE_NONE) {
+                       ifscope = ipoa->ipoa_boundif;
+                       ipf_pktopts.ippo_flags |=
+                           (IPPOF_BOUND_IF | (ifscope << IPPOF_SHIFT_IFSCOPE));
+               }
+
+               /* double negation needed for bool bit field */
+               ipobf.srcbound = !!(ipoa->ipoa_flags & IPOAF_BOUND_SRCADDR);
+               if (ipobf.srcbound)
+                       ipf_pktopts.ippo_flags |= IPPOF_BOUND_SRCADDR;
        } else {
-               select_srcif = FALSE;
+               ipobf.select_srcif = FALSE;
+               ipobf.srcbound = FALSE;
                ifscope = IFSCOPE_NONE;
+               if (flags & IP_OUTARGS) {
+                       ipoa->ipoa_boundif = IFSCOPE_NONE;
+                       ipoa->ipoa_flags &= ~(IPOAF_SELECT_SRCIF |
+                           IPOAF_BOUND_IF | IPOAF_BOUND_SRCADDR);
+               }
        }
 
        if (flags & IP_OUTARGS) {
-               nocell = ipoa->ipoa_nocell;
-               if (nocell)
+               if (ipoa->ipoa_flags & IPOAF_NO_CELLULAR) {
+                       ipobf.nocell = TRUE;
                        ipf_pktopts.ippo_flags |= IPPOF_NO_IFT_CELLULAR;
-       } else {
-               nocell = 0;
+               }
+               if (ipoa->ipoa_flags & IPOAF_NO_EXPENSIVE) {
+                       ipobf.noexpensive = TRUE;
+                       ipf_pktopts.ippo_flags |= IPPOF_NO_IFF_EXPENSIVE;
+               }
+               if (ipoa->ipoa_flags & IPOAF_AWDL_UNRESTRICTED)
+                       ipobf.awdl_unrestricted = TRUE;
+               adv = &ipoa->ipoa_flowadv;
+               adv->code = FADV_SUCCESS;
+               ipoa->ipoa_retflags = 0;
        }
 
-#if IPFIREWALL
-       if (args.rule != NULL) {        /* dummynet already saw us */
+#if IPSEC
+       if (ipsec_bypass == 0 && !(flags & IP_NOIPSEC)) {
+               so = ipsec_getsocket(m);
+               if (so != NULL) {
+                       (void) ipsec_setsocket(m, NULL);
+               }
+       }
+#endif /* IPSEC */
+
+#if DUMMYNET
+       if (args.fwa_ipfw_rule != NULL || args.fwa_pf_rule != NULL) {
+               /* dummynet already saw us */
                ip = mtod(m, struct ip *);
-               hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+               pkt_dst = ip->ip_dst;
                if (ro->ro_rt != NULL) {
                        RT_LOCK_SPIN(ro->ro_rt);
                        ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
@@ -426,51 +520,60 @@ ipfw_tags_done:
                        }
                        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;
-       }
-#endif /* IPFIREWALL */
 
-#if IPSEC
-       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-               so = ipsec_getsocket(m);
-               (void)ipsec_setsocket(m, NULL);
+#if IPFIREWALL
+               if (args.fwa_ipfw_rule != NULL)
+                       goto skip_ipsec;
+#endif /* IPFIREWALL  */
+               if (args.fwa_pf_rule != NULL)
+                       goto sendit;
        }
-#endif
-loopit:        
+#endif /* DUMMYNET */
+
+loopit:
+       packets_processed++;
+       ipobf.isbroadcast = FALSE;
+       ipobf.didfilter = FALSE;
+#if IPFIREWALL_FORWARD
+       ipobf.fwd_rewrite_src = FALSE;
+#endif /* IPFIREWALL_FORWARD */
+
+       VERIFY(m->m_flags & M_PKTHDR);
        /*
-        * No need to proccess packet twice if we've 
-        * already seen it
+        * No need to proccess packet twice if we've already seen it.
         */
        if (!SLIST_EMPTY(&m->m_pkthdr.tags))
                inject_filter_ref = ipf_get_inject_filter(m);
        else
-               inject_filter_ref = 0;
+               inject_filter_ref = NULL;
 
        if (opt) {
                m = ip_insertoptions(m, opt, &len);
                hlen = len;
+               /* Update the chain */
+               if (m != m0) {
+                       if (m0 == packetlist)
+                               packetlist = m;
+                       m0 = m;
+               }
        }
        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).
+        * 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
+       args.fwa_next_hop = next_hop_from_ipfwd_tag;
+       pkt_dst = args.fwa_next_hop ? args.fwa_next_hop->sin_addr : ip->ip_dst;
+#else /* !IPFIREWALL */
        pkt_dst = ip->ip_dst;
-#endif
+#endif /* !IPFIREWALL */
 
        /*
         * We must not send if the packet is destined to network zero.
@@ -484,33 +587,34 @@ loopit:
        /*
         * Fill in IP header.
         */
-       if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
+       if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
                ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
                ip->ip_off &= IP_DF;
-#if RANDOM_IP_ID
-               ip->ip_id = ip_randomid();
-#else
-               ip->ip_id = htons(ip_id++);
-#endif
+               if (rfc6864 && IP_OFF_IS_ATOMIC(ip->ip_off)) {
+                       // Per RFC6864, value of ip_id is undefined for atomic ip packets
+                       ip->ip_id = 0;
+               } else {
+                       ip->ip_id = ip_randomid();
+               }
                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 & 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;
+       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 = SIN(&ro->ro_dst);
 
        /*
         * If there is a cached route,
@@ -521,15 +625,15 @@ loopit:
         */
 
        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)) {
+               if (ROUTE_UNUSABLE(ro) && ip->ip_src.s_addr != INADDR_ANY &&
+                   !(flags & (IP_ROUTETOIF | IP_FORWARDING))) {
                        src_ia = ifa_foraddr(ip->ip_src.s_addr);
                        if (src_ia == NULL) {
                                error = EADDRNOTAVAIL;
                                goto bad;
                        }
                        IFA_REMREF(&src_ia->ia_ifa);
+                       src_ia = NULL;
                }
                /*
                 * Test rt_flags without holding rt_lock for performance
@@ -537,59 +641,68 @@ loopit:
                 * 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 (ROUTE_UNUSABLE(ro) || dst->sin_family != AF_INET ||
+                   dst->sin_addr.s_addr != pkt_dst.s_addr)
+                       ROUTE_RELEASE(ro);
+
                /*
                 * 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 (!ipobf.select_srcif && ro->ro_rt != NULL &&
+                   RT_GENID_OUTOFSYNC(ro->ro_rt))
+                       RT_GENID_SYNC(ro->ro_rt);
        }
        if (ro->ro_rt == NULL) {
-               bzero(dst, sizeof(*dst));
+               bzero(dst, sizeof (*dst));
                dst->sin_family = AF_INET;
-               dst->sin_len = sizeof(*dst);
+               dst->sin_len = sizeof (*dst);
                dst->sin_addr = pkt_dst;
        }
        /*
         * If routing to interface only,
         * short circuit routing lookup.
         */
-#define ifatoia(ifa)   ((struct in_ifaddr *)(ifa))
-#define sintosa(sin)   ((struct sockaddr *)(sin))
        if (flags & IP_ROUTETOIF) {
-               if (ia)
+               if (ia != NULL)
                        IFA_REMREF(&ia->ia_ifa);
-               if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0) {
-                       if ((ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
+               if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) {
+                       ia = ifatoia(ifa_ifwithnet(sintosa(dst)));
+                       if (ia == NULL) {
                                OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
+                               /* XXX IPv6 APN fallback notification?? */
                                goto bad;
                        }
                }
                ifp = ia->ia_ifp;
                ip->ip_ttl = 1;
-               isbroadcast = in_broadcast(dst->sin_addr, ifp);
+               ipobf.isbroadcast = in_broadcast(dst->sin_addr, ifp);
+               /*
+                * For consistency with other cases below.  Loopback
+                * multicast case is handled separately by ip_mloopback().
+                */
+               if ((ifp->if_flags & IFF_LOOPBACK) &&
+                   !IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
+                       m->m_pkthdr.rcvif = ifp;
+                       ip_setsrcifaddr_info(m, ifp->if_index, NULL);
+                       ip_setdstifaddr_info(m, ifp->if_index, NULL);
+               }
        } 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;
+               ipobf.isbroadcast = FALSE;
                if (ia != NULL)
                        IFA_REMREF(&ia->ia_ifa);
 
                /* Macro takes reference on ia */
                IFP_TO_IA(ifp, ia);
        } else {
+               struct ifaddr *ia0 = NULL;
                boolean_t cloneok = FALSE;
                /*
                 * Perform source interface selection; the source IP address
@@ -599,36 +712,38 @@ loopit:
                 * 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 ||
+               if (ipobf.select_srcif &&
+                   ip->ip_src.s_addr != INADDR_ANY && (ROUTE_UNUSABLE(ro) ||
                    !(ro->ro_flags & ROF_SRCIF_SELECTED))) {
-                       struct ifaddr *ifa;
-
                        /* Find the source interface */
-                       ifa = in_selectsrcif(ip, ro, ifscope);
+                       ia0 = 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 the source address belongs to a restricted
+                        * interface and the caller forbids our using
+                        * interfaces of such type, pretend that there is no
+                        * route.
                         */
-                       if (nocell && ifa != NULL &&
-                           ifa->ifa_ifp->if_type == IFT_CELLULAR) {
-                               IFA_REMREF(ifa);
-                               error = EADDRNOTAVAIL;
+                       if (ia0 != NULL &&
+                           IP_CHECK_RESTRICTIONS(ia0->ifa_ifp, ipobf)) {
+                               IFA_REMREF(ia0);
+                               ia0 = NULL;
+                               error = EHOSTUNREACH;
+                               if (flags & IP_OUTARGS)
+                                       ipoa->ipoa_retflags |= IPOARF_IFDENIED;
                                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 the source address is spoofed (in the case of
+                        * IP_RAWOUTPUT on an unbounded socket), 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) {
+                       if (ia0 == NULL && (!(flags & IP_RAWOUTPUT) ||
+                           ipobf.srcbound) && ifscope != lo_ifp->if_index) {
                                error = EADDRNOTAVAIL;
                                goto bad;
                        }
@@ -647,10 +762,9 @@ loopit:
                         * gateway points to that of the default gateway on
                         * the primary interface of the system.
                         */
-                       if (ifa != NULL) {
+                       if (ia0 != NULL) {
                                if (ifscope == IFSCOPE_NONE)
-                                       ifscope = ifa->ifa_ifp->if_index;
-                               IFA_REMREF(ifa);
+                                       ifscope = ia0->ifa_ifp->if_index;
                                cloneok = (!(flags & IP_RAWOUTPUT) &&
                                    !(IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))));
                        }
@@ -703,17 +817,20 @@ loopit:
                                rtalloc_scoped_ign(ro, ign, ifscope);
 
                        /*
-                        * If the route points to a cellular interface and the
-                        * caller forbids our using interfaces of such type,
+                        * If the route points to a cellular/expensive interface
+                        * and the caller forbids our using interfaces of such type,
                         * pretend that there is no route.
                         */
-                       if (nocell && ro->ro_rt != NULL) {
+                       if (ro->ro_rt != NULL) {
                                RT_LOCK_SPIN(ro->ro_rt);
-                               if (ro->ro_rt->rt_ifp->if_type ==
-                                   IFT_CELLULAR) {
+                               if (IP_CHECK_RESTRICTIONS(ro->ro_rt->rt_ifp,
+                                   ipobf)) {
                                        RT_UNLOCK(ro->ro_rt);
-                                       rtfree(ro->ro_rt);
-                                       ro->ro_rt = NULL;
+                                       ROUTE_RELEASE(ro);
+                                       if (flags & IP_OUTARGS) {
+                                               ipoa->ipoa_retflags |=
+                                                   IPOARF_IFDENIED;
+                                       }
                                } else {
                                        RT_UNLOCK(ro->ro_rt);
                                }
@@ -723,35 +840,77 @@ loopit:
                if (ro->ro_rt == NULL) {
                        OSAddAtomic(1, &ipstat.ips_noroute);
                        error = EHOSTUNREACH;
+                       if (ia0 != NULL) {
+                               IFA_REMREF(ia0);
+                               ia0 = NULL;
+                       }
                        goto bad;
                }
 
-               if (ia)
+               if (ia != NULL)
                        IFA_REMREF(&ia->ia_ifa);
                RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
-               if (ia) {
+               if (ia != NULL) {
                        /* Become a regular mutex */
                        RT_CONVERT_LOCK(ro->ro_rt);
                        IFA_ADDREF(&ia->ia_ifa);
                }
+               /*
+                * Note: ia_ifp may not be the same as rt_ifp; the latter
+                * is what we use for determining outbound i/f, mtu, etc.
+                */
                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_GATEWAY) {
+                       dst = SIN(ro->ro_rt->rt_gateway);
+               }
                if (ro->ro_rt->rt_flags & RTF_HOST) {
-                       isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
+                       /* double negation needed for bool bit field */
+                       ipobf.isbroadcast =
+                           !!(ro->ro_rt->rt_flags & RTF_BROADCAST);
                } else {
                        /* Become a regular mutex */
                        RT_CONVERT_LOCK(ro->ro_rt);
-                       isbroadcast = in_broadcast(dst->sin_addr, ifp);
+                       ipobf.isbroadcast = in_broadcast(dst->sin_addr, ifp);
+               }
+               /*
+                * For consistency with IPv6, as well as to ensure that
+                * IP_RECVIF is set correctly for packets that are sent
+                * to one of the local addresses.  ia (rt_ifa) would have
+                * been fixed up by rt_setif for local routes.  This
+                * would make it appear as if the packet arrives on the
+                * interface which owns the local address.  Loopback
+                * multicast case is handled separately by ip_mloopback().
+                */
+               if (ia != NULL && (ifp->if_flags & IFF_LOOPBACK) &&
+                   !IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
+                       uint32_t srcidx;
+
+                       m->m_pkthdr.rcvif = ia->ia_ifa.ifa_ifp;
+
+                       if (ia0 != NULL)
+                               srcidx = ia0->ifa_ifp->if_index;
+                       else if ((ro->ro_flags & ROF_SRCIF_SELECTED) &&
+                           ro->ro_srcia != NULL)
+                               srcidx = ro->ro_srcia->ifa_ifp->if_index;
+                       else
+                               srcidx = 0;
+
+                       ip_setsrcifaddr_info(m, srcidx, NULL);
+                       ip_setdstifaddr_info(m, 0, ia);
                }
                RT_UNLOCK(ro->ro_rt);
+               if (ia0 != NULL) {
+                       IFA_REMREF(ia0);
+                       ia0 = NULL;
+               }
        }
 
        if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
+               struct ifnet *srcifp = NULL;
                struct in_multi *inm;
-               u_int32_t vif;
+               u_int32_t vif = 0;
                u_int8_t ttl = IP_DEFAULT_MULTICAST_TTL;
                u_int8_t loop = IP_DEFAULT_MULTICAST_LOOP;
 
@@ -761,7 +920,7 @@ loopit:
                 * still points to the address in "ro".  (It may have been
                 * changed to point to a gateway address, above.)
                 */
-               dst = (struct sockaddr_in *)&ro->ro_dst;
+               dst = SIN(&ro->ro_dst);
                /*
                 * See if the caller provided any multicast options
                 */
@@ -770,17 +929,12 @@ loopit:
                        vif = imo->imo_multicast_vif;
                        ttl = imo->imo_multicast_ttl;
                        loop = imo->imo_multicast_loop;
-                       if ((flags & IP_RAWOUTPUT) == 0)
+                       if (!(flags & IP_RAWOUTPUT))
                                ip->ip_ttl = ttl;
                        if (imo->imo_multicast_ifp != NULL)
                                ifp = imo->imo_multicast_ifp;
                        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) {
+               } else if (!(flags & IP_RAWOUTPUT)) {
                        vif = -1;
                        ip->ip_ttl = ttl;
                }
@@ -788,7 +942,7 @@ loopit:
                 * Confirm that the outgoing interface supports multicast.
                 */
                if (imo == NULL || vif == -1) {
-                       if ((ifp->if_flags & IFF_MULTICAST) == 0) {
+                       if (!(ifp->if_flags & IFF_MULTICAST)) {
                                OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
                                goto bad;
@@ -805,6 +959,7 @@ loopit:
                                IFA_LOCK_SPIN(&ia1->ia_ifa);
                                if (ia1->ia_ifp == ifp) {
                                        ip->ip_src = IA_SIN(ia1)->sin_addr;
+                                       srcifp = ifp;
                                        IFA_UNLOCK(&ia1->ia_ifa);
                                        break;
                                }
@@ -828,10 +983,11 @@ loopit:
                         */
                        if (!TAILQ_EMPTY(&ipv4_filters)) {
                                struct ipfilter *filter;
-                               int seen = (inject_filter_ref == 0);
+                               int seen = (inject_filter_ref == NULL);
 
                                if (imo != NULL) {
-                                       ipf_pktopts.ippo_flags |= IPPOF_MCAST_OPTS;
+                                       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;
@@ -839,20 +995,26 @@ loopit:
 
                                ipf_ref();
 
-                               /* 4135317 - always pass network byte order to filter */
-
+                               /*
+                                * 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)
+                                               if ((struct ipfilter *)
+                                                   inject_filter_ref == filter)
                                                        seen = 1;
-                                       } else if (filter->ipf_filter.ipf_output) {
+                                       } else if (filter->ipf_filter.
+                                           ipf_output != NULL) {
                                                errno_t result;
-                                               result = filter->ipf_filter.ipf_output(filter->ipf_filter.cookie, (mbuf_t*)&m, ippo);
+                                               result = filter->ipf_filter.
+                                                   ipf_output(filter->
+                                                   ipf_filter.cookie,
+                                                   (mbuf_t *)&m, ippo);
                                                if (result == EJUSTRETURN) {
                                                        ipf_unref();
                                                        INM_REMREF(inm);
@@ -868,49 +1030,15 @@ loopit:
 
                                /* 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
-                        * multicast forwarding as if the packet had just
-                        * arrived on the interface to which we are about
-                        * to send.  The multicast forwarding function
-                        * recursively calls this function, using the
-                        * IP_FORWARDING flag to prevent infinite recursion.
-                        *
-                        * Multicasts that are looped back by ip_mloopback(),
-                        * above, will be forwarded by the ip_input() routine,
-                        * if necessary.
-                        */
-                       if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
-                               /*
-                                * Check if rsvp daemon is running. If not, don't
-                                * set ip_moptions. This ensures that the packet
-                                * is multicast and not just sent down one link
-                                * as prescribed by rsvpd.
-                                */
-                               if (!rsvp_on)
-                                       imo = NULL;
-                               if (ip_mforward(ip, ifp, m, imo) != 0) {
-                                       m_freem(m);
-                                       if (inm != NULL)
-                                               INM_REMREF(inm);
-                                       goto done;
-                               }
+                               ipobf.didfilter = TRUE;
                        }
+                       ip_mloopback(srcifp, ifp, m, dst, hlen);
                }
-#endif /* MROUTING */
                if (inm != NULL)
                        INM_REMREF(inm);
                /*
@@ -928,7 +1056,6 @@ loopit:
 
                goto sendit;
        }
-#ifndef notdef
        /*
         * If source address not specified yet, use address
         * of outgoing interface.
@@ -938,27 +1065,27 @@ loopit:
                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
+               /*
+                * Keep note that we did this - if the firewall changes
                 * the next-hop, our interface may change, changing the
                 * default source IP. It's a shame so much effort happens
-                * twice. Oh well. 
+                * twice. Oh well.
                 */
-               fwd_rewrite_src++;
+               ipobf.fwd_rewrite_src = TRUE;
 #endif /* IPFIREWALL_FORWARD */
        }
-#endif /* notdef */
 
        /*
         * Look for broadcast address and
         * and verify user is allowed to send
         * such a packet.
         */
-       if (isbroadcast) {
-               if ((ifp->if_flags & IFF_BROADCAST) == 0) {
+       if (ipobf.isbroadcast) {
+               if (!(ifp->if_flags & IFF_BROADCAST)) {
                        error = EADDRNOTAVAIL;
                        goto bad;
                }
-               if ((flags & IP_ALLOWBROADCAST) == 0) {
+               if (!(flags & IP_ALLOWBROADCAST)) {
                        error = EACCES;
                        goto bad;
                }
@@ -975,14 +1102,31 @@ loopit:
 sendit:
 #if PF
        /* Invoke outbound packet filter */
-       if ( PF_IS_ENABLED) {
+       if (PF_IS_ENABLED) {
                int rc;
-               rc = pf_af_hook(ifp, mppn, &m, AF_INET, FALSE);
-               if (rc != 0) {
-                       if (packetlist == m0) {
+
+               m0 = m; /* Save for later */
+#if DUMMYNET
+               args.fwa_m = m;
+               args.fwa_next_hop = dst;
+               args.fwa_oif = ifp;
+               args.fwa_ro = ro;
+               args.fwa_dst = dst;
+               args.fwa_oflags = flags;
+               if (flags & IP_OUTARGS)
+                       args.fwa_ipoa = ipoa;
+               rc = pf_af_hook(ifp, mppn, &m, AF_INET, FALSE, &args);
+#else /* DUMMYNET */
+               rc = pf_af_hook(ifp, mppn, &m, AF_INET, FALSE, NULL);
+#endif /* DUMMYNET */
+               if (rc != 0 || m == NULL) {
+                       /* Move to the next packet */
+                       m = *mppn;
+
+                       /* Skip ahead if first packet in list got dropped */
+                       if (packetlist == m0)
                                packetlist = m;
-                               mppn = NULL;
-                       }
+
                        if (m != NULL) {
                                m0 = m;
                                /* Next packet in the chain */
@@ -1000,23 +1144,25 @@ sendit:
                hlen = IP_VHL_HL(ip->ip_vhl) << 2;
        }
 #endif /* PF */
-        /*
-         * Force IP TTL to 255 following draft-ietf-zeroconf-ipv4-linklocal.txt
-         */
-        if (IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)) || IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
+       /*
+        * Force IP TTL to 255 following draft-ietf-zeroconf-ipv4-linklocal.txt
+        */
+       if (IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)) ||
+           IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
                ip_linklocal_stat.iplls_out_total++;
                if (ip->ip_ttl != MAXTTL) {
                        ip_linklocal_stat.iplls_out_badttl++;
-                       ip->ip_ttl = MAXTTL;
+                       ip->ip_ttl = MAXTTL;
                }
-        }
+       }
 
-       if (!didfilter && !TAILQ_EMPTY(&ipv4_filters)) {
+       if (!ipobf.didfilter && !TAILQ_EMPTY(&ipv4_filters)) {
                struct ipfilter *filter;
-               int seen = (inject_filter_ref == 0);
+               int seen = (inject_filter_ref == NULL);
                ipf_pktopts.ippo_flags &= ~IPPOF_MCAST_OPTS;
 
-               /* Check that a TSO frame isn't passed to a filter.
+               /*
+                * 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.
                 */
@@ -1026,21 +1172,22 @@ sendit:
                }
 
                ipf_ref();
-               
-               /* 4135317 - always pass network byte order to filter */
 
+               /* 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)
+                               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, ippo);
+                               result = filter->ipf_filter.
+                                   ipf_output(filter->ipf_filter.cookie,
+                                   (mbuf_t *)&m, ippo);
                                if (result == EJUSTRETURN) {
                                        ipf_unref();
                                        goto done;
@@ -1051,37 +1198,100 @@ sendit:
                                }
                        }
                }
-               
                /* 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();
        }
 
-#if IPSEC
-       /* temporary for testing only: bypass ipsec alltogether */
-
-       if (ipsec_bypass != 0 || (flags & IP_NOIPSEC) != 0)
-               goto skip_ipsec;
+#if NECP
+       /* Process Network Extension Policy. Will Pass, Drop, or Rebind packet. */
+       necp_matched_policy_id = necp_ip_output_find_policy_match (m,
+               flags, (flags & IP_OUTARGS) ? ipoa : NULL, &necp_result, &necp_result_parameter);
+       if (necp_matched_policy_id) {
+               necp_mark_packet_from_ip(m, necp_matched_policy_id);
+               switch (necp_result) {
+                       case NECP_KERNEL_POLICY_RESULT_PASS:
+                               /* Check if the interface is allowed */
+                               if (!necp_packet_is_allowed_over_interface(m, ifp)) {
+                                       error = EHOSTUNREACH;
+                                       OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+                                       goto bad;
+                               }
+                               goto skip_ipsec;
+                       case NECP_KERNEL_POLICY_RESULT_DROP:
+                       case NECP_KERNEL_POLICY_RESULT_SOCKET_DIVERT:
+                               /* Flow divert packets should be blocked at the IP layer */
+                               error = EHOSTUNREACH;
+                               OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+                               goto bad;
+                       case NECP_KERNEL_POLICY_RESULT_IP_TUNNEL: {
+                               /* Verify that the packet is being routed to the tunnel */
+                               struct ifnet *policy_ifp = necp_get_ifnet_from_result_parameter(&necp_result_parameter);
+                               if (policy_ifp == ifp) {
+                                       /* Check if the interface is allowed */
+                                       if (!necp_packet_is_allowed_over_interface(m, ifp)) {
+                                               error = EHOSTUNREACH;
+                                               OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+                                               goto bad;
+                                       }
+                                       goto skip_ipsec;
+                               } else {
+                                       if (necp_packet_can_rebind_to_ifnet(m, policy_ifp, &necp_route, AF_INET)) {
+                                               /* Check if the interface is allowed */
+                                               if (!necp_packet_is_allowed_over_interface(m, policy_ifp)) {
+                                                       error = EHOSTUNREACH;
+                                                       OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+                                                       goto bad;
+                                               }
 
-       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
+                                               /* Set ifp to the tunnel interface, since it is compatible with the packet */
+                                               ifp = policy_ifp;
+                                               ro = &necp_route;
+                                               goto skip_ipsec;
+                                       } else {
+                                               error = ENETUNREACH;
+                                               OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+                                               goto bad;
+                                       }
+                               }
+                       }
+                       default:
+                               break;
+               }
+       }
+       /* Catch-all to check if the interface is allowed */
+       if (!necp_packet_is_allowed_over_interface(m, ifp)) {
+               error = EHOSTUNREACH;
+               OSAddAtomic(1, &ipstat.ips_necp_policy_drop);
+               goto bad;
+       }
+#endif /* NECP */
 
+#if IPSEC
+       if (ipsec_bypass != 0 || (flags & IP_NOIPSEC))
+               goto skip_ipsec;
 
-       /* get SP for this packet */
-       if (so == NULL)
-               sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
-       else
-               sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
+       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_START, 0, 0, 0, 0, 0);
 
        if (sp == NULL) {
-               IPSEC_STAT_INCREMENT(ipsecstat.out_inval);              
-               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 0,0,0,0,0);
-               goto bad;
+               /* get SP for this packet */
+               if (so != NULL) {
+                       sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND,
+                               so, &error);
+               } else {
+                       sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
+                               flags, &error);
+               }
+               if (sp == NULL) {
+                       IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                                                0, 0, 0, 0, 0);
+                       goto bad;
+               }
        }
 
        error = 0;
@@ -1094,20 +1304,30 @@ sendit:
                 * This packet is just discarded.
                 */
                IPSEC_STAT_INCREMENT(ipsecstat.out_polvio);
-               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 1,0,0,0,0);
+               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                   1, 0, 0, 0, 0);
                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);
+               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                   2, 0, 0, 0, 0);
                goto skip_ipsec;
-       
+
        case IPSEC_POLICY_IPSEC:
                if (sp->req == NULL) {
                        /* acquire a policy */
                        error = key_spdacquire(sp);
-                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 3,0,0,0,0);
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                           3, 0, 0, 0, 0);
+                       goto bad;
+               }
+               if (sp->ipsec_if) {
+                       /* Verify the redirect to ipsec interface */
+                       if (sp->ipsec_if == ifp) {
+                               goto skip_ipsec;
+                       }
                        goto bad;
                }
                break;
@@ -1116,13 +1336,14 @@ sendit:
        default:
                printf("ip_output: Invalid policy found. %d\n", sp->policy);
        }
-    {
+       {
        ipsec_state.m = m;
        if (flags & IP_ROUTETOIF) {
-               bzero(&ipsec_state.ro, sizeof(ipsec_state.ro));
-       } else
-               route_copyout(&ipsec_state.ro, ro, sizeof(ipsec_state.ro));
-       ipsec_state.dst = (struct sockaddr *)dst;
+               bzero(&ipsec_state.ro, sizeof (ipsec_state.ro));
+       } else {
+               route_copyout((struct route *)&ipsec_state.ro, ro, sizeof (struct route));
+       }
+       ipsec_state.dst = SA(dst);
 
        ip->ip_sum = 0;
 
@@ -1130,11 +1351,8 @@ sendit:
         * XXX
         * delayed checksums are not currently compatible with IPsec
         */
-       if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
+       if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
                in_delayed_cksum(m);
-               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
-       }
-
 
 #if BYTE_ORDER != BIG_ENDIAN
        HTONS(ip->ip_len);
@@ -1142,13 +1360,28 @@ sendit:
 #endif
 
        DTRACE_IP6(send, struct mbuf *, m, struct inpcb *, NULL,
-               struct ip *, ip, struct ifnet *, ifp,
-               struct ip *, ip, struct ip6_hdr *, NULL);
+           struct ip *, ip, struct ifnet *, ifp,
+           struct ip *, ip, struct ip6_hdr *, NULL);
 
        error = ipsec4_output(&ipsec_state, sp, flags);
-    
+       if (ipsec_state.tunneled == 6) {
+               m0 = m = NULL;
+               error = 0;
+               goto bad;
+       }
+
        m0 = m = ipsec_state.m;
-       
+
+#if DUMMYNET
+       /*
+        * If we're about to use the route in ipsec_state
+        * and this came from dummynet, cleaup now.
+        */
+       if (ro == &saved_route &&
+           (!(flags & IP_ROUTETOIF) || ipsec_state.tunneled))
+               ROUTE_RELEASE(ro);
+#endif /* DUMMYNET */
+
        if (flags & IP_ROUTETOIF) {
                /*
                 * if we have tunnel mode SA, we may need to ignore
@@ -1156,14 +1389,12 @@ sendit:
                 */
                if (ipsec_state.tunneled) {
                        flags &= ~IP_ROUTETOIF;
-                       ipsec_saved_route = ro;
-                       ro = &ipsec_state.ro;
+                       ro = (struct route *)&ipsec_state.ro;
                }
        } else {
-               ipsec_saved_route = ro;
-               ro = &ipsec_state.ro;
+               ro = (struct route *)&ipsec_state.ro;
        }
-       dst = (struct sockaddr_in *)ipsec_state.dst;
+       dst = SIN(ipsec_state.dst);
        if (error) {
                /* mbuf is already reclaimed in ipsec4_output. */
                m0 = NULL;
@@ -1176,55 +1407,59 @@ sendit:
                        break;
                default:
                        printf("ip4_output (ipsec): error code %d\n", error);
-                       /*fall through*/
+                       /* FALLTHRU */
                case ENOENT:
                        /* don't show these error codes to the user */
                        error = 0;
                        break;
                }
-               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 4,0,0,0,0);
+               KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                   4, 0, 0, 0, 0);
                goto bad;
        }
-    }
+       }
 
        /* be sure to update variables that are affected by ipsec4_output() */
        ip = mtod(m, struct ip *);
-       
+
 #ifdef _IP_VHL
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
-#else
+#else /* !_IP_VHL */
        hlen = ip->ip_hl << 2;
-#endif
+#endif /* !_IP_VHL */
        /* Check that there wasn't a route change and src is still valid */
-       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)) {
+       if (ROUTE_UNUSABLE(ro)) {
+               ROUTE_RELEASE(ro);
+               VERIFY(src_ia == NULL);
+               if (ip->ip_src.s_addr != INADDR_ANY &&
+                   !(flags & (IP_ROUTETOIF | IP_FORWARDING)) &&
+                   (src_ia = ifa_foraddr(ip->ip_src.s_addr)) == NULL) {
                        error = EADDRNOTAVAIL;
                        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
-                           5,0,0,0,0);
+                           5, 0, 0, 0, 0);
                        goto bad;
                }
-               rtfree(ro->ro_rt);
-               ro->ro_rt = NULL;
-               if (src_ia != NULL)
+               if (src_ia != NULL) {
                        IFA_REMREF(&src_ia->ia_ifa);
+                       src_ia = NULL;
+               }
        }
 
        if (ro->ro_rt == NULL) {
-               if ((flags & IP_ROUTETOIF) == 0) {
-                       printf("ip_output: can't update route after "
-                           "IPsec processing\n");
-                       error = EHOSTUNREACH;   /*XXX*/
+               if (!(flags & IP_ROUTETOIF)) {
+                       printf("%s: can't update route after "
+                           "IPsec processing\n", __func__);
+                       error = EHOSTUNREACH;   /* XXX */
                        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
-                           6,0,0,0,0);
+                           6, 0, 0, 0, 0);
                        goto bad;
                }
        } else {
-               if (ia)
+               if (ia != NULL)
                        IFA_REMREF(&ia->ia_ifa);
                RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
-               if (ia) {
+               if (ia != NULL) {
                        /* Become a regular mutex */
                        RT_CONVERT_LOCK(ro->ro_rt);
                        IFA_ADDREF(&ia->ia_ifa);
@@ -1234,21 +1469,21 @@ sendit:
        }
 
        /* 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);
-       
+       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;
-               
+
                ipf_pktopts.ippo_flags &= ~IPPOF_MCAST_OPTS;
 
-               /* Check that a TSO frame isn't passed to a filter.
+               /*
+                * 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.
                 */
@@ -1258,18 +1493,18 @@ sendit:
                }
 
                ipf_ref();
-               
-               /* 4135317 - always pass network byte order to filter */
 
+               /* 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, ippo);
+                               result = filter->ipf_filter.
+                                   ipf_output(filter->ipf_filter.cookie,
+                                   (mbuf_t *)&m, ippo);
                                if (result == EJUSTRETURN) {
                                        ipf_unref();
                                        goto done;
@@ -1280,79 +1515,60 @@ sendit:
                                }
                        }
                }
-               
                /* 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();
        }
 skip_ipsec:
-#endif /*IPSEC*/
+#endif /* IPSEC */
 
 #if IPFIREWALL
-       /*
-        * IpHack's section.
-        * - Xlate: translate packet's addr/port (NAT).
-        * - Firewall: deny/allow/etc.
-        * - Wrap: fake packet's addr/port <unimpl.>
-        * - Encapsulate: put it in another IP and send out. <unimp.>
-        */ 
-       if (fr_checkp) {
-               struct  mbuf    *m1 = m;
-
-               if ((error = (*fr_checkp)(ip, hlen, ifp, 1, &m1)) || !m1) {
-                       goto done;
-               }
-               ip = mtod(m0 = m = m1, struct ip *);
-       }
-
        /*
         * Check with the firewall...
         * but not if we are already being fwd'd from a firewall.
         */
-       if (fw_enable && IPFW_LOADED && !args.next_hop) {
+       if (fw_enable && IPFW_LOADED && !args.fwa_next_hop) {
                struct sockaddr_in *old = dst;
 
-               args.m = m;
-               args.next_hop = dst;
-               args.oif = ifp;
-               off = ip_fw_chk_ptr(&args);
-               m = args.m;
-               dst = args.next_hop;
-
-                /*
-                 * On return we must do the following:
-                 * IP_FW_PORT_DENY_FLAG                -> drop the pkt (XXX new)
-                 * 1<=off<= 0xffff   -> DIVERT
-                 * (off & IP_FW_PORT_DYNT_FLAG)        -> send to a DUMMYNET pipe
-                 * (off & IP_FW_PORT_TEE_FLAG) -> TEE the packet
-                 * dst != old        -> IPFIREWALL_FORWARD
-                 * off==0, dst==old  -> accept
-                 * If some of the above modules is not compiled in, then
-                 * we should't have to check the corresponding condition
-                 * (because the ipfw control socket should not accept
-                 * unsupported rules), but better play safe and drop
-                 * packets in case of doubt.
-                 */
+               args.fwa_m = m;
+               args.fwa_next_hop = dst;
+               args.fwa_oif = ifp;
+               ipfwoff = ip_fw_chk_ptr(&args);
+               m = args.fwa_m;
+               dst = args.fwa_next_hop;
+
+               /*
+                * On return we must do the following:
+                *   IP_FW_PORT_DENY_FLAG         -> drop the pkt (XXX new)
+                *   1<=off<= 0xffff              -> DIVERT
+                *   (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
+                *   (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
+                *   dst != old                   -> IPFIREWALL_FORWARD
+                *   off==0, dst==old             -> accept
+                * If some of the above modules is not compiled in, then
+                * we should't have to check the corresponding condition
+                * (because the ipfw control socket should not accept
+                * unsupported rules), but better play safe and drop
+                * packets in case of doubt.
+                */
                m0 = m;
-               if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
+               if ((ipfwoff & IP_FW_PORT_DENY_FLAG) || m == NULL) {
                        if (m)
                                m_freem(m);
-                       error = EACCES ;
-                       goto done ;
+                       error = EACCES;
+                       goto done;
                }
                ip = mtod(m, struct ip *);
-               
-               if (off == 0 && dst == old) {/* common case */
-                       goto pass ;
+
+               if (ipfwoff == 0 && dst == old) {       /* common case */
+                       goto pass;
                }
 #if DUMMYNET
-                if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG) != 0) {
+               if (DUMMYNET_LOADED && (ipfwoff & IP_FW_PORT_DYNT_FLAG) != 0) {
                        /*
                         * pass the pkt to dummynet. Need to include
                         * pipe number, m, ifp, ro, dst because these are
@@ -1362,33 +1578,31 @@ skip_ipsec:
                         * 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;
+                       args.fwa_ro = ro;
+                       args.fwa_dst = dst;
+                       args.fwa_oflags = flags;
                        if (flags & IP_OUTARGS)
-                               args.ipoa = ipoa;
+                               args.fwa_ipoa = ipoa;
 
-                       error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
-                           &args);
+                       error = ip_dn_io_ptr(m, ipfwoff & 0xffff, DN_TO_IP_OUT,
+                           &args, DN_CLIENT_IPFW);
                        goto done;
                }
 #endif /* DUMMYNET */
 #if IPDIVERT
-               if (off != 0 && (off & IP_FW_PORT_DYNT_FLAG) == 0) {
+               if (ipfwoff != 0 && (ipfwoff & IP_FW_PORT_DYNT_FLAG) == 0) {
                        struct mbuf *clone = NULL;
 
                        /* Clone packet if we're doing a 'tee' */
-                       if ((off & IP_FW_PORT_TEE_FLAG) != 0)
+                       if ((ipfwoff & IP_FW_PORT_TEE_FLAG) != 0)
                                clone = m_dup(m, M_DONTWAIT);
                        /*
                         * XXX
                         * delayed checksums are not currently compatible
                         * with divert sockets.
                         */
-                       if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
+                       if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
                                in_delayed_cksum(m);
-                               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
-                       }
 
                        /* Restore packet header fields to original values */
 
@@ -1398,7 +1612,8 @@ skip_ipsec:
 #endif
 
                        /* Deliver packet to divert input routine */
-                       divert_packet(m, 0, off & 0xffff, args.divert_rule);
+                       divert_packet(m, 0, ipfwoff & 0xffff,
+                           args.fwa_divert_rule);
 
                        /* If 'tee', continue with original packet */
                        if (clone != NULL) {
@@ -1408,11 +1623,11 @@ skip_ipsec:
                        }
                        goto done;
                }
-#endif
-
+#endif /* IPDIVERT */
 #if IPFIREWALL_FORWARD
-               /* Here we check dst to make sure it's directly reachable on the
-                * interface we previously thought it was.
+               /*
+                * Here we check dst to make sure it's directly reachable on
+                * the interface we previously thought it was.
                 * If it isn't (which may be likely in some situations) we have
                 * to re-route it (ie, find a route for the next-hop and the
                 * associated interface) and set them here. This is nested
@@ -1420,27 +1635,25 @@ skip_ipsec:
                 * such control is nigh impossible. So we do it here.
                 * And I'm babbling.
                 */
-               if (off == 0 && old != dst) {
+               if (ipfwoff == 0 && old != dst) {
                        struct in_ifaddr *ia_fw;
+                       struct route *ro_fwd = &sro_fwd;
 
-                       /* It's changed... */
-                       /* There must be a better way to do this next line... */
-                       static struct route sro_fwd, *ro_fwd = &sro_fwd;
 #if IPFIREWALL_FORWARD_DEBUG
                        printf("IPFIREWALL_FORWARD: New dst ip: ");
                        print_ip(dst->sin_addr);
                        printf("\n");
-#endif
+#endif /* IPFIREWALL_FORWARD_DEBUG */
                        /*
                         * We need to figure out if we have been forwarded
-                        * to a local socket. If so then we should somehow 
+                        * to a local socket. If so then we should somehow
                         * "loop back" to ip_input, and get directed to the
                         * PCB as if we had received this packet. This is
                         * because it may be dificult to identify the packets
                         * you want to forward until they are being output
                         * and have selected an interface. (e.g. locally
                         * initiated packets) If we used the loopback inteface,
-                        * we would not be able to control what happens 
+                        * we would not be able to control what happens
                         * as the packet runs through ip_input() as
                         * it is done through a ISR.
                         */
@@ -1462,7 +1675,7 @@ skip_ipsec:
                        lck_rw_done(in_ifaddr_rwlock);
                        if (ia_fw) {
                                /* tell ip_input "dont filter" */
-                               struct m_tag            *fwd_tag;
+                               struct m_tag            *fwd_tag;
                                struct ip_fwd_tag       *ipfwd_tag;
 
                                fwd_tag = m_tag_create(KERNEL_MODULE_TAG_ID,
@@ -1474,55 +1687,42 @@ skip_ipsec:
                                }
 
                                ipfwd_tag = (struct ip_fwd_tag *)(fwd_tag+1);
-                               ipfwd_tag->next_hop = args.next_hop;
+                               ipfwd_tag->next_hop = args.fwa_next_hop;
 
                                m_tag_prepend(m, fwd_tag);
 
                                if (m->m_pkthdr.rcvif == NULL)
                                        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) {
-                                               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
-                                               m->m_pkthdr.csum_flags |=
-                                                       CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
-                                               m->m_pkthdr.csum_data = 0xffff;
-                                       }
-                                       m->m_pkthdr.csum_flags |=
-                                               CSUM_IP_CHECKED | CSUM_IP_VALID;
-                               }
-                               else if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
-                                       in_delayed_cksum(m);
-                                       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);
-#endif                         
-                               
-                               /*  we need to call dlil_output to run filters
-                                *      and resync to avoid recursion loops.
+#endif
+                               mbuf_outbound_finalize(m, PF_INET, 0);
+
+                               /*
+                                * we need to call dlil_output to run filters
+                                * and resync to avoid recursion loops.
                                 */
                                if (lo_ifp) {
-                                       dlil_output(lo_ifp, PF_INET, m, 0, (struct sockaddr *)dst, 0);
-                               }
-                               else {
-                                       printf("ip_output: no loopback ifp for forwarding!!!\n");
+                                       dlil_output(lo_ifp, PF_INET, m, NULL,
+                                           SA(dst), 0, adv);
+                               } else {
+                                       printf("%s: no loopback ifp for "
+                                           "forwarding!!!\n", __func__);
                                }
                                goto done;
                        }
-                       /* Some of the logic for this was
-                        * nicked from above.
+                       /*
+                        * Some of the logic for this was nicked from above.
                         *
                         * This rewrites the cached route in a local PCB.
                         * Is this what we want to do?
                         */
-                       bcopy(dst, &ro_fwd->ro_dst, sizeof(*dst));
+                       ROUTE_RELEASE(ro_fwd);
+                       bcopy(dst, &ro_fwd->ro_dst, sizeof (*dst));
 
-                       ro_fwd->ro_rt = NULL;
-                       rtalloc_ign(ro_fwd, RTF_PRCLONING);
+                       rtalloc_ign(ro_fwd, RTF_PRCLONING, false);
 
                        if (ro_fwd->ro_rt == NULL) {
                                OSAddAtomic(1, &ipstat.ips_noroute);
@@ -1540,19 +1740,22 @@ skip_ipsec:
                        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;
+                               dst = SIN(ro_fwd->ro_rt->rt_gateway);
                        if (ro_fwd->ro_rt->rt_flags & RTF_HOST) {
-                               isbroadcast =
-                                   (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
+                               /* double negation needed for bool bit field */
+                               ipobf.isbroadcast =
+                                   !!(ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
                        } else {
                                /* Become a regular mutex */
                                RT_CONVERT_LOCK(ro_fwd->ro_rt);
-                               isbroadcast = in_broadcast(dst->sin_addr, ifp);
+                               ipobf.isbroadcast =
+                                   in_broadcast(dst->sin_addr, ifp);
                        }
                        RT_UNLOCK(ro_fwd->ro_rt);
-                       rtfree(ro->ro_rt);
+                       ROUTE_RELEASE(ro);
                        ro->ro_rt = ro_fwd->ro_rt;
-                       dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
+                       ro_fwd->ro_rt = NULL;
+                       dst = SIN(&ro_fwd->ro_dst);
 
                        /*
                         * If we added a default src ip earlier,
@@ -1560,20 +1763,20 @@ skip_ipsec:
                         * interface, do it again, from the new one.
                         */
                        if (ia_fw != NULL) {
-                               if (fwd_rewrite_src) {
+                               if (ipobf.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 ;
+                       goto pass;
                }
 #endif /* IPFIREWALL_FORWARD */
-                /*
-                 * if we get here, none of the above matches, and 
-                 * we have to drop the pkt
-                 */
+               /*
+                * if we get here, none of the above matches, and
+                * we have to drop the pkt
+                */
                m_freem(m);
                error = EACCES; /* not sure this is the right error msg */
                goto done;
@@ -1581,109 +1784,91 @@ skip_ipsec:
 
 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)) {
+
+       /* 127/8 must not appear on wire - RFC1122 */
+       if (!(ifp->if_flags & IFF_LOOPBACK) &&
+           ((ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
+           (ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET)) {
                OSAddAtomic(1, &ipstat.ips_badaddr);
-               m_freem(m);
-               /* 
-                * Do not simply drop the packet just like a firewall -- we want the 
-                * the application to feel the pain.
-                * Return ENETUNREACH like ip6_output does in some similar cases. 
-                * This can startle the otherwise clueless process that specifies
-                * loopback as the source address.
-                */
-               error = ENETUNREACH;
-               goto done;
+               error = EADDRNOTAVAIL;
+               goto bad;
        }
-#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);
 
-       if ((ifp->if_hwassist & CSUM_TCP_SUM16) != 0) {
-               /*
-                * Special case code for GMACE
-                * frames that can be checksumed by GMACE SUM16 HW:
-                * frame >64, no fragments, no UDP
-                */
-               if (apple_hwcksum_tx && (m->m_pkthdr.csum_flags & CSUM_TCP)
-                       && (ip->ip_len > 50) && (ip->ip_len <= ifp->if_mtu)) {
-                       /* Apple GMAC HW, expects STUFF_OFFSET << 16  | START_OFFSET */
-                       u_short offset = (IP_VHL_HL(ip->ip_vhl) << 2) +14 ; /* IP+Enet header length */
-                       u_short csumprev= m->m_pkthdr.csum_data & 0xFFFF;
-                       m->m_pkthdr.csum_flags = CSUM_DATA_VALID | CSUM_TCP_SUM16; /* for GMAC */
-                       m->m_pkthdr.csum_data = (csumprev + offset)  << 16 ;
-                       m->m_pkthdr.csum_data += offset; 
-                       sw_csum = CSUM_DELAY_IP; /* do IP hdr chksum in software */
-               }
-               else {
-                       /* let the software handle any UDP or TCP checksums */
-                       sw_csum |= (CSUM_DELAY_DATA & m->m_pkthdr.csum_flags);
+       if (ipoa != NULL) {
+               u_int8_t dscp = ip->ip_tos >> IPTOS_DSCP_SHIFT;
+
+               error = set_packet_qos(m, ifp,
+                   ipoa->ipoa_flags & IPOAF_QOSMARKING_ALLOWED ? TRUE : FALSE,
+                   ipoa->ipoa_sotc, ipoa->ipoa_netsvctype, &dscp);
+               if (error == 0) {
+                       ip->ip_tos &= IPTOS_ECN_MASK;
+                       ip->ip_tos |= dscp << IPTOS_DSCP_SHIFT;
+               } else {
+                       printf("%s if_dscp_for_mbuf() error %d\n", __func__, error);
+                       error = 0;
                }
-       } 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) {
-               in_delayed_cksum(m);
-               sw_csum &= ~CSUM_DELAY_DATA;
-               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
 
-       if (apple_hwcksum_tx != 0) {
-               m->m_pkthdr.csum_flags &=
-                   IF_HWASSIST_CSUM_FLAGS(ifp->if_hwassist);
-       } else {
-               m->m_pkthdr.csum_flags = 0;
+       /*
+        * Some Wi-Fi AP implementations do not correctly handle multicast IP
+        * packets with DSCP bits set -- see radr://9331522 -- so as a
+        * workaround we clear the DSCP bits and set the service class to BE
+        */
+       if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) && IFNET_IS_WIFI_INFRA(ifp)) {
+               ip->ip_tos &= IPTOS_ECN_MASK;
+               mbuf_set_service_class(m, MBUF_SC_BE);
        }
 
+       ip_output_checksum(ifp, m, (IP_VHL_HL(ip->ip_vhl) << 2),
+           ip->ip_len, &sw_csum);
+
        /*
         * 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 || tso ||
-           ifp->if_hwassist & CSUM_FRAGMENT) {
-               if (tso) 
-                       m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
-                       
-
+       if ((u_short)ip->ip_len <= ifp->if_mtu || TSO_IPV4_OK(ifp, m) ||
+           (!(ip->ip_off & IP_DF) && (ifp->if_hwassist & CSUM_FRAGMENT))) {
 #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);
-               }
-               
-#ifndef __APPLE__
-               /* Record statistics for this interface address. */
-               if (!(flags & IP_FORWARDING) && ia != NULL) {
-                       ia->ia_ifa.if_opackets++;
-                       ia->ia_ifa.if_obytes += m->m_pkthdr.len;
+                       ip->ip_sum = ip_cksum_hdr_out(m, hlen);
+                       sw_csum &= ~CSUM_DELAY_IP;
+                       m->m_pkthdr.csum_flags &= ~CSUM_DELAY_IP;
                }
-#endif
 
 #if IPSEC
                /* clean ipsec history once it goes out of the node */
-               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0)
+               if (ipsec_bypass == 0 && !(flags & IP_NOIPSEC))
                        ipsec_delaux(m);
-#endif
+#endif /* IPSEC */
+               if ((m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) &&
+                   (m->m_pkthdr.tso_segsz > 0))
+                       scnt += m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
+               else
+                       scnt++;
+
                if (packetchain == 0) {
-                       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);
+                       if (ro->ro_rt != NULL && nstat_collect)
+                               nstat_route_tx(ro->ro_rt, scnt,
+                                   m->m_pkthdr.len, 0);
+
+                       error = dlil_output(ifp, PF_INET, m, ro->ro_rt,
+                           SA(dst), 0, adv);
+                       if (dlil_verbose && error) {
+                               printf("dlil_output error on interface %s: %d\n",
+                                       ifp->if_xname, error);
+                       }
+                       scnt = 0;
                        goto done;
-               }
-               else { /* packet chaining allows us to reuse the route for all packets */
+               } 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;
@@ -1693,15 +1878,21 @@ 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
-                               error = ifnet_output(ifp, PF_INET, packetlist,
-                                   ro->ro_rt, (struct sockaddr *)dst);
+                               if (ro->ro_rt != NULL && nstat_collect)
+                                       nstat_route_tx(ro->ro_rt, scnt,
+                                           bytecnt, 0);
+
+                               error = dlil_output(ifp, PF_INET, packetlist,
+                                   ro->ro_rt, SA(dst), 0, adv);
+                               if (dlil_verbose && error) {
+                                       printf("dlil_output error on interface %s: %d\n",
+                                       ifp->if_xname, error);
+                               }
                                pktcnt = 0;
+                               scnt = 0;
                                bytecnt = 0;
                                goto done;
-       
+
                        }
                        m0 = m;
                        pktcnt++;
@@ -1711,10 +1902,10 @@ sendchain:
        /*
         * Too large for interface; fragment if possible.
         * Must be able to put at least 8 bytes per fragment.
+        * Balk when DF bit is set or the interface didn't support TSO.
         */
-
-       if (ip->ip_off & IP_DF  || (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) ||
-               pktcnt > 0) {
+       if ((ip->ip_off & IP_DF) || pktcnt > 0 ||
+           (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4)) {
                error = EMSGSIZE;
                /*
                 * This case can happen if the user changed the MTU
@@ -1725,9 +1916,9 @@ sendchain:
                 */
                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)) {
+                       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);
@@ -1745,60 +1936,82 @@ sendchain:
                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);
+       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)
+               if (ipsec_bypass == 0 && !(flags & IP_NOIPSEC))
                        ipsec_delaux(m);
-#endif
+#endif /* IPSEC */
                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;
+                       if ((packetchain != 0) && (pktcnt > 0)) {
+                               panic("%s: mix of packet in packetlist is "
+                                   "wrong=%p", __func__, packetlist);
+                               /* NOTREACHED */
                        }
-#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
+                       if (ro->ro_rt != NULL && nstat_collect) {
+                               nstat_route_tx(ro->ro_rt, 1,
+                                   m->m_pkthdr.len, 0);
+                       }
+                       error = dlil_output(ifp, PF_INET, m, ro->ro_rt,
+                           SA(dst), 0, adv);
+                       if (dlil_verbose && error) {
+                               printf("dlil_output error on interface %s: %d\n",
+                                          ifp->if_xname, error);
+                       }
+               } else {
                        m_freem(m);
+               }
        }
 
        if (error == 0)
                OSAddAtomic(1, &ipstat.ips_fragmented);
 
 done:
-       if (ia) {
+       if (ia != NULL) {
                IFA_REMREF(&ia->ia_ifa);
                ia = NULL;
        }
 #if IPSEC
-       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-               if (ipsec_state.ro.ro_rt)
-                       rtfree(ipsec_state.ro.ro_rt);
+       ROUTE_RELEASE(&ipsec_state.ro);
        if (sp != NULL) {
                KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
-                       printf("DP ip_output call free SP:%x\n", sp));
+                   printf("DP ip_output call free SP:%x\n", sp));
                key_freesp(sp, KEY_SADB_UNLOCKED);
        }
-       }
 #endif /* IPSEC */
+#if NECP
+       ROUTE_RELEASE(&necp_route);
+#endif /* NECP */
+#if DUMMYNET
+       ROUTE_RELEASE(&saved_route);
+#endif /* DUMMYNET */
+#if IPFIREWALL_FORWARD
+       ROUTE_RELEASE(&sro_fwd);
+#endif /* IPFIREWALL_FORWARD */
 
-       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error,0,0,0,0);
+       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error, 0, 0, 0, 0);
+       if (ip_output_measure) {
+               net_perf_measure_time(&net_perf, &start_tv, packets_processed);
+               net_perf_histogram(&net_perf, packets_processed);
+       }
        return (error);
 bad:
-       m_freem(m0);
+       if (pktcnt > 0)
+               m0 = packetlist;
+       m_freem_list(m0);
        goto done;
+
+#undef ipsec_state
+#undef args
+#undef sro_fwd
+#undef saved_route
+#undef ipf_pktopts
+#undef IP_CHECK_RESTRICTIONS
 }
 
 int
@@ -1812,9 +2025,9 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
        ip = mtod(m, struct ip *);
 #ifdef _IP_VHL
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
-#else
+#else /* !_IP_VHL */
        hlen = ip->ip_hl << 2;
-#endif
+#endif /* !_IP_VHL */
 
        firstlen = len = (mtu - hlen) &~ 7;
        if (len < 8) {
@@ -1826,11 +2039,9 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
         * if the interface will not calculate checksums on
         * fragmented packets, then do it here.
         */
-       if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
-           (ifp->if_hwassist & CSUM_IP_FRAGS) == 0) {
+       if ((m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
+           !(ifp->if_hwassist & CSUM_IP_FRAGS))
                in_delayed_cksum(m);
-               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
-       }
 
        /*
         * Loop through length of segment after first fragment,
@@ -1840,7 +2051,7 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
        mhlen = sizeof (struct ip);
        for (off = hlen + len; off < (u_short)ip->ip_len; off += len) {
                MGETHDR(m, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
-               if (m == 0) {
+               if (m == NULL) {
                        error = ENOBUFS;
                        OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
@@ -1863,19 +2074,22 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
                        mhip->ip_off |= IP_MF;
                mhip->ip_len = htons((u_short)(len + mhlen));
                m->m_next = m_copy(m0, off, len);
-               if (m->m_next == 0) {
+               if (m->m_next == NULL) {
                        (void) m_free(m);
                        error = ENOBUFS;        /* ??? */
                        OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
                }
                m->m_pkthdr.len = mhlen + len;
-               m->m_pkthdr.rcvif = 0;
+               m->m_pkthdr.rcvif = NULL;
                m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
-               m->m_pkthdr.socket_id = m0->m_pkthdr.socket_id;
+
+               M_COPY_CLASSIFIER(m, m0);
+               M_COPY_PFTAG(m, m0);
+
 #if CONFIG_MACF_NET
                mac_netinet_fragment(m0, m);
-#endif
+#endif /* CONFIG_MACF_NET */
 
 #if BYTE_ORDER != BIG_ENDIAN
                HTONS(mhip->ip_off);
@@ -1883,7 +2097,8 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
 
                mhip->ip_sum = 0;
                if (sw_csum & CSUM_DELAY_IP) {
-                       mhip->ip_sum = in_cksum(m, mhlen);
+                       mhip->ip_sum = ip_cksum_hdr_out(m, mhlen);
+                       m->m_pkthdr.csum_flags &= ~CSUM_DELAY_IP;
                }
                *mnext = m;
                mnext = &m->m_nextpkt;
@@ -1909,10 +2124,11 @@ ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
 #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);
+               ip->ip_sum = ip_cksum_hdr_out(m, hlen);
+               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_IP;
        }
 sendorfree:
        if (error)
@@ -1937,46 +2153,64 @@ ip_out_cksum_stats(int proto, u_int32_t len)
        }
 }
 
-void
-in_delayed_cksum_offset(struct mbuf *m0, int ip_offset)
+/*
+ * Process a delayed payload checksum calculation (outbound path.)
+ *
+ * hoff is the number of bytes beyond the mbuf data pointer which
+ * points to the IP header.
+ *
+ * Returns a bitmask representing all the work done in software.
+ */
+uint32_t
+in_finalize_cksum(struct mbuf *m, uint32_t hoff, uint32_t csum_flags)
 {
+       unsigned char buf[15 << 2] __attribute__((aligned(8)));
        struct ip *ip;
-       unsigned char buf[sizeof(struct ip)];
-       u_short csum, offset, ip_len;
+       uint32_t offset, _hlen, mlen, hlen, len, sw_csum;
+       uint16_t csum, ip_len;
 
-        /* Save copy of first mbuf pointer and the ip_offset before modifying */
-        struct mbuf *m = m0;
-        int ip_offset_copy = ip_offset;
+       _CASSERT(sizeof (csum) == sizeof (uint16_t));
+       VERIFY(m->m_flags & M_PKTHDR);
 
-       while (ip_offset >= m->m_len) {
-               ip_offset -= m->m_len;
-               m = m->m_next;
-               if (m == NULL) {
-                       printf("in_delayed_cksum_withoffset failed - ip_offset wasn't in the packet\n");
-                       return;
-               }
+       sw_csum = (csum_flags & m->m_pkthdr.csum_flags);
+
+       if ((sw_csum &= (CSUM_DELAY_IP | CSUM_DELAY_DATA)) == 0)
+               goto done;
+
+       mlen = m->m_pkthdr.len;                         /* total mbuf len */
+
+       /* sanity check (need at least simple IP header) */
+       if (mlen < (hoff + sizeof (*ip))) {
+               panic("%s: mbuf %p pkt len (%u) < hoff+ip_hdr "
+                   "(%u+%u)\n", __func__, m, mlen, hoff,
+                   (uint32_t)sizeof (*ip));
+               /* NOTREACHED */
        }
-       
-       /* 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);
-#endif
-               m_copydata(m, ip_offset, sizeof(struct ip), (caddr_t) buf);
-               
-               ip = (struct ip *)buf;
+
+       /*
+        * In case the IP header is not contiguous, or not 32-bit aligned,
+        * or if we're computing the IP header checksum, copy it to a local
+        * buffer.  Copy only the simple IP header here (IP options case
+        * is handled below.)
+        */
+       if ((sw_csum & CSUM_DELAY_IP) || (hoff + sizeof (*ip)) > m->m_len ||
+           !IP_HDR_ALIGNED_P(mtod(m, caddr_t) + hoff)) {
+               m_copydata(m, hoff, sizeof (*ip), (caddr_t)buf);
+               ip = (struct ip *)(void *)buf;
+               _hlen = sizeof (*ip);
        } else {
-               ip = (struct ip*)(m->m_data + ip_offset);
+               ip = (struct ip *)(void *)(m->m_data + hoff);
+               _hlen = 0;
        }
-       
-       /* Gross */
-       if (ip_offset) {
-               m->m_len -= ip_offset;
-               m->m_data += ip_offset;
+
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;              /* IP header len */
+
+       /* sanity check */
+       if (mlen < (hoff + hlen)) {
+               panic("%s: mbuf %p pkt too short (%d) for IP header (%u), "
+                   "hoff %u", __func__, m, mlen, hlen, hoff);
+               /* NOTREACHED */
        }
-       
-       offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
 
        /*
         * We could be in the context of an IP or interface filter; in the
@@ -1984,155 +2218,117 @@ in_delayed_cksum_offset(struct mbuf *m0, int ip_offset)
         * 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.
+        * the length and check again.  If it still fails, use the actual
+        * packet length.  This also covers the trailing bytes case.
         */
        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;
+       if (ip_len != (mlen - hoff)) {
+               ip_len = OSSwapInt16(ip_len);
+               if (ip_len != (mlen - hoff)) {
+                       printf("%s: mbuf 0x%llx proto %d IP len %d (%x) "
+                           "[swapped %d (%x)] doesn't match actual packet "
+                           "length; %d is used instead\n", __func__,
+                           (uint64_t)VM_KERNEL_ADDRPERM(m), ip->ip_p,
+                           ip->ip_len, ip->ip_len, ip_len, ip_len,
+                           (mlen - hoff));
+                       ip_len = mlen - hoff;
                }
        }
 
-       csum = in_cksum_skip(m, ip_len, offset);
+       len = ip_len - hlen;                            /* csum span */
+
+       if (sw_csum & CSUM_DELAY_DATA) {
+               uint16_t ulpoff;
 
-       /* Update stats */
-       ip_out_cksum_stats(ip->ip_p, ip_len - offset);
+               /*
+                * offset is added to the lower 16-bit value of csum_data,
+                * which is expected to contain the ULP offset; therefore
+                * CSUM_PARTIAL offset adjustment must be undone.
+                */
+               if ((m->m_pkthdr.csum_flags & (CSUM_PARTIAL|CSUM_DATA_VALID)) ==
+                   (CSUM_PARTIAL|CSUM_DATA_VALID)) {
+                       /*
+                        * Get back the original ULP offset (this will
+                        * undo the CSUM_PARTIAL logic in ip_output.)
+                        */
+                       m->m_pkthdr.csum_data = (m->m_pkthdr.csum_tx_stuff -
+                           m->m_pkthdr.csum_tx_start);
+               }
 
-       if (m0->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
-               csum = 0xffff;
-       offset += m0->m_pkthdr.csum_data & 0xFFFF;        /* checksum offset */
+               ulpoff = (m->m_pkthdr.csum_data & 0xffff); /* ULP csum offset */
+               offset = hoff + hlen;                   /* ULP header */
 
-       /* Gross */
-       if (ip_offset) {
-               if (M_LEADINGSPACE(m) < ip_offset)
-                       panic("in_delayed_cksum_offset - chain modified!\n");
-               m->m_len += ip_offset;
-               m->m_data -= ip_offset;
-       }
+               if (mlen < (ulpoff + sizeof (csum))) {
+                       panic("%s: mbuf %p pkt len (%u) proto %d invalid ULP "
+                           "cksum offset (%u) cksum flags 0x%x\n", __func__,
+                           m, mlen, ip->ip_p, ulpoff, m->m_pkthdr.csum_flags);
+                       /* NOTREACHED */
+               }
 
-       if (offset > ip_len) /* bogus offset */
-               return;
+               csum = inet_cksum(m, 0, offset, len);
 
-       /* Insert the checksum in the existing chain */
-       if (offset + ip_offset + sizeof(u_short) > m->m_len) {
-               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);
-#endif
-               *(u_short *)tmp = csum;
-               m_copyback(m, offset + ip_offset, 2, tmp);
-       } else
-               *(u_short *)(m->m_data + offset + ip_offset) = csum;
-}
+               /* Update stats */
+               ip_out_cksum_stats(ip->ip_p, len);
 
-void
-in_delayed_cksum(struct mbuf *m)
-{
-       in_delayed_cksum_offset(m, 0);
-}
+               /* RFC1122 4.1.3.4 */
+               if (csum == 0 &&
+                   (m->m_pkthdr.csum_flags & (CSUM_UDP|CSUM_ZERO_INVERT)))
+                       csum = 0xffff;
 
-void
-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) {
-               ip_offset -= m->m_len;
-               m = m->m_next;
-               if (m == NULL) {
-                       printf("in_cksum_offset failed - ip_offset wasn't in the packet\n");
-                       return;
+               /* Insert the checksum in the ULP csum field */
+               offset += ulpoff;
+               if (offset + sizeof (csum) > m->m_len) {
+                       m_copyback(m, offset, sizeof (csum), &csum);
+               } else if (IP_HDR_ALIGNED_P(mtod(m, char *) + hoff)) {
+                       *(uint16_t *)(void *)(mtod(m, char *) + offset) = csum;
+               } else {
+                       bcopy(&csum, (mtod(m, char *) + offset), sizeof (csum));
                }
+               m->m_pkthdr.csum_flags &= ~(CSUM_DELAY_DATA | CSUM_DATA_VALID |
+                   CSUM_PARTIAL | CSUM_ZERO_INVERT);
        }
-       
-       /* Sometimes the IP header is not contiguous, yes this can happen! */
-       if (ip_offset + sizeof(struct ip) > m->m_len) {
 
-#if DEBUG
-               printf("in_cksum_offset - delayed m_pullup, m->len: %d  off: %lu\n",
-                       m->m_len, ip_offset);
-#endif 
-               m_copydata(m, ip_offset, sizeof(struct ip), (caddr_t) buf);
+       if (sw_csum & CSUM_DELAY_IP) {
+               /* IP header must be in the local buffer */
+               VERIFY(_hlen == sizeof (*ip));
+               if (_hlen != hlen) {
+                       VERIFY(hlen <= sizeof (buf));
+                       m_copydata(m, hoff, hlen, (caddr_t)buf);
+                       ip = (struct ip *)(void *)buf;
+                       _hlen = hlen;
+               }
 
-               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);
+               /*
+                * Compute the IP header checksum as if the IP length
+                * is the length which we believe is "correct"; see
+                * how ip_len gets calculated above.  Note that this
+                * is done on the local copy and not on the real one.
+                */
+               ip->ip_len = htons(ip_len);
                ip->ip_sum = 0;
-       }
-       
-       /* Gross */
-       if (ip_offset) {
-               m->m_len -= ip_offset;
-               m->m_data += ip_offset;
-       }
-
-#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;
-               }
-       }
+               csum = in_cksum_hdr_opt(ip);
 
-       ip->ip_sum = 0;
-       ip->ip_sum = in_cksum(m, hlen);
-       if (swapped)
-               ip->ip_len = SWAP16(ip->ip_len);
+               /* Update stats */
+               ipstat.ips_snd_swcsum++;
+               ipstat.ips_snd_swcsum_bytes += hlen;
 
-       /* Gross */
-       if (ip_offset) {
-               if (M_LEADINGSPACE(m) < ip_offset)
-                       panic("in_cksum_offset - chain modified!\n");
-               m->m_len += ip_offset;
-               m->m_data -= ip_offset;
+               /*
+                * Insert only the checksum in the existing IP header
+                * csum field; all other fields are left unchanged.
+                */
+               offset = hoff + offsetof(struct ip, ip_sum);
+               if (offset + sizeof (csum) > m->m_len) {
+                       m_copyback(m, offset, sizeof (csum), &csum);
+               } else if (IP_HDR_ALIGNED_P(mtod(m, char *) + hoff)) {
+                       *(uint16_t *)(void *)(mtod(m, char *) + offset) = csum;
+               } else {
+                       bcopy(&csum, (mtod(m, char *) + offset), sizeof (csum));
+               }
+               m->m_pkthdr.csum_flags &= ~CSUM_DELAY_IP;
        }
 
-       /* 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);
-       }
+done:
+       return (sw_csum);
 }
 
 /*
@@ -2143,46 +2339,43 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
  * XXX This routine assumes that the packet has no options in place.
  */
 static struct mbuf *
-ip_insertoptions(m, opt, phlen)
-       register struct mbuf *m;
-       struct mbuf *opt;
-       int *phlen;
+ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
 {
-       register struct ipoption *p = mtod(opt, struct ipoption *);
+       struct ipoption *p = mtod(opt, struct ipoption *);
        struct mbuf *n;
-       register struct ip *ip = mtod(m, struct ip *);
+       struct ip *ip = mtod(m, struct ip *);
        unsigned optlen;
 
-       optlen = opt->m_len - sizeof(p->ipopt_dst);
+       optlen = opt->m_len - sizeof (p->ipopt_dst);
        if (optlen + (u_short)ip->ip_len > IP_MAXPACKET)
                return (m);             /* XXX should fail */
        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);      /* MAC-OK */
-               if (n == 0)
+               if (n == NULL)
                        return (m);
                n->m_pkthdr.rcvif = 0;
 #if CONFIG_MACF_NET
                mac_mbuf_label_copy(m, n);
-#endif
+#endif /* CONFIG_MACF_NET */
                n->m_pkthdr.len = m->m_pkthdr.len + optlen;
-               m->m_len -= sizeof(struct ip);
-               m->m_data += sizeof(struct ip);
+               m->m_len -= sizeof (struct ip);
+               m->m_data += sizeof (struct ip);
                n->m_next = m;
                m = n;
-               m->m_len = optlen + sizeof(struct ip);
+               m->m_len = optlen + sizeof (struct ip);
                m->m_data += max_linkhdr;
-               (void)memcpy(mtod(m, void *), ip, sizeof(struct ip));
+               (void) memcpy(mtod(m, void *), ip, sizeof (struct ip));
        } else {
                m->m_data -= optlen;
                m->m_len += optlen;
                m->m_pkthdr.len += optlen;
-               ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
+               ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof (struct ip));
        }
        ip = mtod(m, struct ip *);
        bcopy(p->ipopt_list, ip + 1, optlen);
-       *phlen = sizeof(struct ip) + optlen;
+       *phlen = sizeof (struct ip) + optlen;
        ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
        ip->ip_len += optlen;
        return (m);
@@ -2192,11 +2385,10 @@ ip_insertoptions(m, opt, phlen)
  * Copy options from ip to jp,
  * omitting those not copied during fragmentation.
  */
-int
-ip_optcopy(ip, jp)
-       struct ip *ip, *jp;
+static int
+ip_optcopy(struct ip *ip, struct ip *jp)
 {
-       register u_char *cp, *dp;
+       u_char *cp, *dp;
        int opt, optlen, cnt;
 
        cp = (u_char *)(ip + 1);
@@ -2213,13 +2405,17 @@ ip_optcopy(ip, jp)
                        continue;
                }
 #if DIAGNOSTIC
-               if (cnt < IPOPT_OLEN + sizeof(*cp))
+               if (cnt < IPOPT_OLEN + sizeof (*cp)) {
                        panic("malformed IPv4 option passed to ip_optcopy");
+                       /* NOTREACHED */
+               }
 #endif
                optlen = cp[IPOPT_OLEN];
 #if DIAGNOSTIC
-               if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
+               if (optlen < IPOPT_OLEN + sizeof (*cp) || optlen > cnt) {
                        panic("malformed IPv4 option passed to ip_optcopy");
+                       /* NOTREACHED */
+               }
 #endif
                /* bogus lengths should have been caught by ip_dooptions */
                if (optlen > cnt)
@@ -2238,45 +2434,44 @@ ip_optcopy(ip, jp)
  * IP socket option processing.
  */
 int
-ip_ctloutput(so, sopt)
-       struct socket *so;
-       struct sockopt *sopt;
+ip_ctloutput(struct socket *so, struct sockopt *sopt)
 {
        struct  inpcb *inp = sotoinpcb(so);
        int     error, optval;
 
        error = optval = 0;
-       if (sopt->sopt_level != IPPROTO_IP) {
+       if (sopt->sopt_level != IPPROTO_IP)
                return (EINVAL);
-       }
 
        switch (sopt->sopt_dir) {
        case SOPT_SET:
                switch (sopt->sopt_name) {
-               case IP_OPTIONS:
 #ifdef notyet
                case IP_RETOPTS:
 #endif
-               {
+               case IP_OPTIONS: {
                        struct mbuf *m;
+
                        if (sopt->sopt_valsize > MLEN) {
                                error = EMSGSIZE;
                                break;
                        }
                        MGET(m, sopt->sopt_p != kernproc ? M_WAIT : M_DONTWAIT,
                            MT_HEADER);
-                       if (m == 0) {
+                       if (m == NULL) {
                                error = ENOBUFS;
                                break;
                        }
                        m->m_len = sopt->sopt_valsize;
-                       error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
-                                           m->m_len);
-                       if (error)
+                       error = sooptcopyin(sopt, mtod(m, char *),
+                           m->m_len, m->m_len);
+                       if (error) {
+                               m_freem(m);
                                break;
-                       
-                       return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
-                                          m));
+                       }
+
+                       return (ip_pcbopts(sopt->sopt_name,
+                           &inp->inp_options, m));
                }
 
                case IP_TOS:
@@ -2286,12 +2481,10 @@ ip_ctloutput(so, sopt)
                case IP_RECVDSTADDR:
                case IP_RECVIF:
                case IP_RECVTTL:
-#if defined(NFAITH) && NFAITH > 0
-               case IP_FAITH:
-#endif
                case IP_RECVPKTINFO:
-                       error = sooptcopyin(sopt, &optval, sizeof optval,
-                                           sizeof optval);
+               case IP_RECVTOS:
+                       error = sooptcopyin(sopt, &optval, sizeof (optval),
+                           sizeof (optval));
                        if (error)
                                break;
 
@@ -2329,81 +2522,16 @@ ip_ctloutput(so, sopt)
                                OPTSET(INP_RECVTTL);
                                break;
 
-#if defined(NFAITH) && NFAITH > 0
-                       case IP_FAITH:
-                               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;
+                       case IP_RECVTOS:
+                               OPTSET(INP_RECVTOS);
                                break;
+ #undef OPTSET
                        }
-
-                       /* 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
+                       break;
                /*
                 * Multicast socket options are processed by the in_mcast
                 * module.
@@ -2430,8 +2558,8 @@ ip_ctloutput(so, sopt)
                        break;
 
                case IP_PORTRANGE:
-                       error = sooptcopyin(sopt, &optval, sizeof optval,
-                                           sizeof optval);
+                       error = sooptcopyin(sopt, &optval, sizeof (optval),
+                           sizeof (optval));
                        if (error)
                                break;
 
@@ -2458,8 +2586,7 @@ ip_ctloutput(so, sopt)
                        break;
 
 #if IPSEC
-               case IP_IPSEC_POLICY:
-               {
+               case IP_IPSEC_POLICY: {
                        caddr_t req = NULL;
                        size_t len = 0;
                        int priv;
@@ -2480,14 +2607,15 @@ ip_ctloutput(so, sopt)
                        m_freem(m);
                        break;
                }
-#endif /*IPSEC*/
+#endif /* IPSEC */
 
 #if TRAFFIC_MGT
-               case IP_TRAFFIC_MGT_BACKGROUND:
-               {
-                       unsigned        background = 0;
-                       error = sooptcopyin(sopt, &background, sizeof(background), sizeof(background));
-                       if (error) 
+               case IP_TRAFFIC_MGT_BACKGROUND: {
+                       unsigned background = 0;
+
+                       error = sooptcopyin(sopt, &background,
+                           sizeof (background), sizeof (background));
+                       if (error)
                                break;
 
                        if (background) {
@@ -2533,7 +2661,7 @@ ip_ctloutput(so, sopt)
                        if (error)
                                break;
 
-                       inp_bindif(inp, optval);
+                       error = inp_bindif(inp, optval, NULL);
                        break;
 
                case IP_NO_IFT_CELLULAR:
@@ -2549,7 +2677,14 @@ ip_ctloutput(so, sopt)
                        if (error)
                                break;
 
-                       error = inp_nocellular(inp, optval);
+                       /* once set, it cannot be unset */
+                       if (!optval && INP_NO_CELLULAR(inp)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       error = so_set_restrictions(so,
+                           SO_RESTRICT_DENY_CELLULAR);
                        break;
 
                case IP_OUT_IF:
@@ -2567,13 +2702,13 @@ ip_ctloutput(so, sopt)
                switch (sopt->sopt_name) {
                case IP_OPTIONS:
                case IP_RETOPTS:
-                       if (inp->inp_options)
-                               error = sooptcopyout(sopt, 
-                                                    mtod(inp->inp_options,
-                                                         char *),
-                                                    inp->inp_options->m_len);
-                       else
+                       if (inp->inp_options) {
+                               error = sooptcopyout(sopt,
+                                   mtod(inp->inp_options, char *),
+                                   inp->inp_options->m_len);
+                       } else {
                                sopt->sopt_valsize = 0;
+                       }
                        break;
 
                case IP_TOS:
@@ -2584,12 +2719,9 @@ ip_ctloutput(so, sopt)
                case IP_RECVIF:
                case IP_RECVTTL:
                case IP_PORTRANGE:
-#if defined(NFAITH) && NFAITH > 0
-               case IP_FAITH:
-#endif
                case IP_RECVPKTINFO:
+               case IP_RECVTOS:
                        switch (sopt->sopt_name) {
-
                        case IP_TOS:
                                optval = inp->inp_ip_tos;
                                break;
@@ -2629,16 +2761,15 @@ ip_ctloutput(so, sopt)
                                        optval = 0;
                                break;
 
-#if defined(NFAITH) && NFAITH > 0
-                       case IP_FAITH:
-                               optval = OPTBIT(INP_FAITH);
-                               break;
-#endif
                        case IP_RECVPKTINFO:
                                optval = OPTBIT(INP_PKTINFO);
                                break;
+
+                       case IP_RECVTOS:
+                               optval = OPTBIT(INP_RECVTOS);
+                               break;
                        }
-                       error = sooptcopyout(sopt, &optval, sizeof optval);
+                       error = sooptcopyout(sopt, &optval, sizeof (optval));
                        break;
 
                case IP_MULTICAST_IF:
@@ -2651,47 +2782,35 @@ ip_ctloutput(so, sopt)
                        break;
 
 #if IPSEC
-               case IP_IPSEC_POLICY:
-               {
-                       struct mbuf *m = NULL;
-                       caddr_t req = NULL;
-                       size_t len = 0;
-
-                       if (m != 0) {
-                               req = mtod(m, caddr_t);
-                               len = m->m_len;
-                       }
-                       error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
-                       if (error == 0)
-                               error = soopt_mcopyout(sopt, m); /* XXX */
-                       if (error == 0)
-                               m_freem(m);
+               case IP_IPSEC_POLICY: {
+                       error = 0; /* This option is no longer supported */
                        break;
                }
-#endif /*IPSEC*/
+#endif /* IPSEC */
 
 #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;
+               case IP_TRAFFIC_MGT_BACKGROUND: {
+                       unsigned background = (so->so_flags1 &
+                           SOF1_TRAFFIC_MGT_SO_BACKGROUND) ? 1 : 0;
+                       return (sooptcopyout(sopt, &background,
+                           sizeof (background)));
                }
 #endif /* TRAFFIC_MGT */
 
                case IP_BOUND_IF:
                        if (inp->inp_flags & INP_BOUND_IF)
-                               optval = inp->inp_boundif;
+                               optval = inp->inp_boundifp->if_index;
                        error = sooptcopyout(sopt, &optval, sizeof (optval));
                        break;
 
                case IP_NO_IFT_CELLULAR:
-                       optval = (inp->inp_flags & INP_NO_IFT_CELLULAR) ? 1 : 0;
+                       optval = INP_NO_CELLULAR(inp) ? 1 : 0;
                        error = sooptcopyout(sopt, &optval, sizeof (optval));
                        break;
 
                case IP_OUT_IF:
-                       optval = inp->inp_last_outif;
+                       optval = (inp->inp_last_outifp != NULL) ?
+                           inp->inp_last_outifp->if_index : 0;
                        error = sooptcopyout(sopt, &optval, sizeof (optval));
                        break;
 
@@ -2710,44 +2829,41 @@ ip_ctloutput(so, sopt)
  * with destination address if source routed.
  */
 static int
-ip_pcbopts(
-       __unused int optname,
-       struct mbuf **pcbopt,
-       register struct mbuf *m)
+ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
 {
-       register int cnt, optlen;
-       register u_char *cp;
+#pragma unused(optname)
+       int cnt, optlen;
+       u_char *cp;
        u_char opt;
 
        /* turn off any old options */
        if (*pcbopt)
-               (void)m_free(*pcbopt);
+               (void) m_free(*pcbopt);
        *pcbopt = 0;
        if (m == (struct mbuf *)0 || m->m_len == 0) {
                /*
                 * Only turning off any previous options.
                 */
                if (m)
-                       (void)m_free(m);
+                       (void) m_free(m);
                return (0);
        }
 
-#ifndef        vax
-       if (m->m_len % sizeof(int32_t))
+       if (m->m_len % sizeof (int32_t))
                goto bad;
-#endif
+
        /*
         * IP first-hop destination address will be stored before
         * actual options; move other options back
         * and clear it when none present.
         */
-       if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
+       if (m->m_data + m->m_len + sizeof (struct in_addr) >= &m->m_dat[MLEN])
                goto bad;
        cnt = m->m_len;
-       m->m_len += sizeof(struct in_addr);
-       cp = mtod(m, u_char *) + sizeof(struct in_addr);
+       m->m_len += sizeof (struct in_addr);
+       cp = mtod(m, u_char *) + sizeof (struct in_addr);
        ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
-       bzero(mtod(m, caddr_t), sizeof(struct in_addr));
+       bzero(mtod(m, caddr_t), sizeof (struct in_addr));
 
        for (; cnt > 0; cnt -= optlen, cp += optlen) {
                opt = cp[IPOPT_OPTVAL];
@@ -2756,10 +2872,10 @@ ip_pcbopts(
                if (opt == IPOPT_NOP)
                        optlen = 1;
                else {
-                       if (cnt < IPOPT_OLEN + sizeof(*cp))
+                       if (cnt < IPOPT_OLEN + sizeof (*cp))
                                goto bad;
                        optlen = cp[IPOPT_OLEN];
-                       if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
+                       if (optlen < IPOPT_OLEN + sizeof (*cp) || optlen > cnt)
                                goto bad;
                }
                switch (opt) {
@@ -2777,35 +2893,35 @@ ip_pcbopts(
                         * A is first hop destination, which doesn't appear in
                         * actual IP option, but is stored before the options.
                         */
-                       if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
+                       if (optlen < IPOPT_MINOFF - 1 + sizeof (struct in_addr))
                                goto bad;
-                       m->m_len -= sizeof(struct in_addr);
-                       cnt -= sizeof(struct in_addr);
-                       optlen -= sizeof(struct in_addr);
+                       m->m_len -= sizeof (struct in_addr);
+                       cnt -= sizeof (struct in_addr);
+                       optlen -= sizeof (struct in_addr);
                        cp[IPOPT_OLEN] = optlen;
                        /*
                         * Move first hop before start of options.
                         */
                        bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
-                           sizeof(struct in_addr));
+                           sizeof (struct in_addr));
                        /*
                         * Then copy rest of options back
                         * to close up the deleted entry.
                         */
                        ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
-                           sizeof(struct in_addr)),
+                           sizeof (struct in_addr)),
                            (caddr_t)&cp[IPOPT_OFFSET+1],
-                           (unsigned)cnt + sizeof(struct in_addr));
+                           (unsigned)cnt + sizeof (struct in_addr));
                        break;
                }
        }
-       if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
+       if (m->m_len > MAX_IPOPTLEN + sizeof (struct in_addr))
                goto bad;
        *pcbopt = m;
        return (0);
 
 bad:
-       (void)m_free(m);
+       (void) m_free(m);
        return (EINVAL);
 }
 
@@ -2951,18 +3067,23 @@ ip_allocmoptions(int how)
  * replicating that code here.
  */
 static void
-ip_mloopback(ifp, m, dst, hlen)
-       struct ifnet *ifp;
-       register struct mbuf *m;
-       register struct sockaddr_in *dst;
-       int hlen;
+ip_mloopback(struct ifnet *srcifp, struct ifnet *origifp, struct mbuf *m,
+    struct sockaddr_in *dst, int hlen)
 {
-       register struct ip *ip;
        struct mbuf *copym;
-       int sw_csum = (apple_hwcksum_tx == 0);
+       struct ip *ip;
+
+       if (lo_ifp == NULL)
+               return;
 
-       copym = m_copy(m, 0, M_COPYALL);
-       if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
+       /*
+        * Copy the packet header as it's needed for the checksum
+        * Make sure to deep-copy IP header portion in case the data
+        * is in an mbuf cluster, so that we can safely override the IP
+        * header portion later.
+        */
+       copym = m_copym_mode(m, 0, M_COPYALL, M_DONTWAIT, M_COPYM_COPY_HDR);
+       if (copym != NULL && ((copym->m_flags & M_EXT) || copym->m_len < hlen))
                copym = m_pullup(copym, hlen);
 
        if (copym == NULL)
@@ -2973,83 +3094,65 @@ ip_mloopback(ifp, m, dst, hlen)
         * 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);
+       ip->ip_sum = ip_cksum_hdr_out(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().
+        * Mark checksum as valid unless receive checksum offload is
+        * disabled; if so, compute checksum in software.  If the
+        * interface itself is lo0, this will be overridden by if_loop.
         */
-#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;
-       }
-#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 (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 (hwcksum_rx) {
+               copym->m_pkthdr.csum_flags &= ~(CSUM_PARTIAL|CSUM_ZERO_INVERT);
+               copym->m_pkthdr.csum_flags |=
+                   CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
+               copym->m_pkthdr.csum_data = 0xffff;
+       } else if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 #if BYTE_ORDER != BIG_ENDIAN
-                       NTOHS(ip->ip_len);
+               NTOHS(ip->ip_len);
 #endif
-                       
-                       in_delayed_cksum(copym);
-
+               in_delayed_cksum(copym);
 #if BYTE_ORDER != BIG_ENDIAN
-                       HTONS(ip->ip_len);
+               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.
         */
+       copym->m_pkthdr.rcvif = origifp;
 
        /*
-        * 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.
+        * Also record the source interface (which owns the source address).
+        * This is basically a stripped down version of ifa_foraddr().
         */
-       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 (srcifp == NULL) {
+               struct in_ifaddr *ia;
+
+               lck_rw_lock_shared(in_ifaddr_rwlock);
+               TAILQ_FOREACH(ia, INADDR_HASH(ip->ip_src.s_addr), ia_hash) {
+                       IFA_LOCK_SPIN(&ia->ia_ifa);
+                       if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_src.s_addr) {
+                               srcifp = ia->ia_ifp;
+                               IFA_UNLOCK(&ia->ia_ifa);
+                               break;
+                       }
+                       IFA_UNLOCK(&ia->ia_ifa);
+               }
+               lck_rw_done(in_ifaddr_rwlock);
        }
+       if (srcifp != NULL)
+               ip_setsrcifaddr_info(copym, srcifp->if_index, NULL);
+       ip_setdstifaddr_info(copym, origifp->if_index, NULL);
+
+       dlil_output(lo_ifp, PF_INET, copym, NULL, SA(dst), 0, NULL);
 }
 
 /*
@@ -3071,6 +3174,8 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
        struct ifnet *rt_ifp;
        char s_src[MAX_IPv4_STR_LEN], s_dst[MAX_IPv4_STR_LEN];
 
+       VERIFY(src.s_addr != INADDR_ANY);
+
        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));
@@ -3103,7 +3208,7 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
                if (scope == IFSCOPE_NONE) {
                        scope = rt_ifp->if_index;
                        if (scope != get_primary_ifscope(AF_INET) &&
-                           ro->ro_rt->generation_id != route_generation)
+                           ROUTE_UNUSABLE(ro))
                                scope = get_primary_ifscope(AF_INET);
                }
 
@@ -3169,7 +3274,7 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
                        sin.sin_addr = dst;
 
                        lck_mtx_lock(rnh_lock);
-                       if ((rt = rt_lookup(TRUE, (struct sockaddr *)&sin, NULL,
+                       if ((rt = rt_lookup(TRUE, SA(&sin), NULL,
                            rt_tables[AF_INET], IFSCOPE_NONE)) != NULL) {
                                RT_LOCK(rt);
                                /*
@@ -3280,9 +3385,7 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
                }
 
                RT_UNLOCK(ro->ro_rt);
-               rtfree(ro->ro_rt);
-               ro->ro_rt = NULL;
-               ro->ro_flags &= ~ROF_SRCIF_SELECTED;
+               ROUTE_RELEASE(ro);
 
                /*
                 * If the destination is IPv4 LLA and the route's interface
@@ -3317,8 +3420,13 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
        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))) {
+               if (ifa != NULL)
+                       IFA_ADDREF(ifa);        /* for route */
+               if (ro->ro_srcia != NULL)
+                       IFA_REMREF(ro->ro_srcia);
+               ro->ro_srcia = ifa;
                ro->ro_flags |= ROF_SRCIF_SELECTED;
-               ro->ro_rt->generation_id = route_generation;
+               RT_GENID_SYNC(ro->ro_rt);
        }
 
        if (ro->ro_rt != NULL)
@@ -3326,3 +3434,142 @@ in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
 
        return (ifa);
 }
+
+void
+ip_output_checksum(struct ifnet *ifp, struct mbuf *m, int hlen, int ip_len,
+    uint32_t *sw_csum)
+{
+       int tso = TSO_IPV4_OK(ifp, m);
+       uint32_t hwcap = ifp->if_hwassist;
+
+       m->m_pkthdr.csum_flags |= CSUM_IP;
+
+       if (!hwcksum_tx) {
+               /* do all in software; hardware checksum offload is disabled */
+               *sw_csum = (CSUM_DELAY_DATA | CSUM_DELAY_IP) &
+                   m->m_pkthdr.csum_flags;
+       } else {
+               /* do in software what the hardware cannot */
+               *sw_csum = m->m_pkthdr.csum_flags &
+                   ~IF_HWASSIST_CSUM_FLAGS(hwcap);
+       }
+
+       if (hlen != sizeof (struct ip)) {
+               *sw_csum |= ((CSUM_DELAY_DATA | CSUM_DELAY_IP) &
+                   m->m_pkthdr.csum_flags);
+       } else if (!(*sw_csum & CSUM_DELAY_DATA) && (hwcap & CSUM_PARTIAL)) {
+               /*
+                * Partial checksum offload, if non-IP fragment, and TCP only
+                * (no UDP support, as the hardware may not be able to convert
+                * +0 to -0 (0xffff) per RFC1122 4.1.3.4. unless the interface
+                * supports "invert zero" capability.)
+                */
+               if (hwcksum_tx && !tso &&
+                   ((m->m_pkthdr.csum_flags & CSUM_TCP) ||
+                   ((hwcap & CSUM_ZERO_INVERT) &&
+                   (m->m_pkthdr.csum_flags & CSUM_ZERO_INVERT))) &&
+                   ip_len <= ifp->if_mtu) {
+                       uint16_t start = sizeof (struct ip);
+                       uint16_t ulpoff = m->m_pkthdr.csum_data & 0xffff;
+                       m->m_pkthdr.csum_flags |=
+                           (CSUM_DATA_VALID | CSUM_PARTIAL);
+                       m->m_pkthdr.csum_tx_stuff = (ulpoff + start);
+                       m->m_pkthdr.csum_tx_start = start;
+                       /* do IP hdr chksum in software */
+                       *sw_csum = CSUM_DELAY_IP;
+               } else {
+                       *sw_csum |= (CSUM_DELAY_DATA & m->m_pkthdr.csum_flags);
+               }
+       }
+
+       if (*sw_csum & CSUM_DELAY_DATA) {
+               in_delayed_cksum(m);
+               *sw_csum &= ~CSUM_DELAY_DATA;
+       }
+
+       if (hwcksum_tx) {
+               /*
+                * Drop off bits that aren't supported by hardware;
+                * also make sure to preserve non-checksum related bits.
+                */
+               m->m_pkthdr.csum_flags =
+                   ((m->m_pkthdr.csum_flags &
+                   (IF_HWASSIST_CSUM_FLAGS(hwcap) | CSUM_DATA_VALID)) |
+                   (m->m_pkthdr.csum_flags & ~IF_HWASSIST_CSUM_MASK));
+       } else {
+               /* drop all bits; hardware checksum offload is disabled */
+               m->m_pkthdr.csum_flags = 0;
+       }
+}
+
+/*
+ * GRE protocol output for PPP/PPTP
+ */
+int
+ip_gre_output(struct mbuf *m)
+{
+       struct route ro;
+       int error;
+
+       bzero(&ro, sizeof (ro));
+
+       error = ip_output(m, NULL, &ro, 0, NULL, NULL);
+
+       ROUTE_RELEASE(&ro);
+
+       return (error);
+}
+
+static int
+sysctl_reset_ip_output_stats SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error, i;
+
+       i = ip_output_measure;
+       error = sysctl_handle_int(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       /* impose bounds */
+       if (i < 0 || i > 1) {
+               error = EINVAL;
+               goto done;
+       }
+       if (ip_output_measure != i && i == 1) {
+               net_perf_initialize(&net_perf, ip_output_measure_bins);
+       }
+       ip_output_measure = i;
+done:
+       return (error);
+}
+
+static int
+sysctl_ip_output_measure_bins SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+       int error;
+       uint64_t i;
+
+       i = ip_output_measure_bins;
+       error = sysctl_handle_quad(oidp, &i, 0, req);
+       if (error || req->newptr == USER_ADDR_NULL)
+               goto done;
+       /* validate data */
+       if (!net_perf_validate_bins(i)) {
+               error = EINVAL;
+               goto done;
+       }
+       ip_output_measure_bins = i;
+done:
+       return (error);
+}
+
+static int
+sysctl_ip_output_getperf SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+       if (req->oldptr == USER_ADDR_NULL)
+               req->oldlen = (size_t)sizeof (struct ipstat);
+
+       return (SYSCTL_OUT(req, &net_perf, MIN(sizeof (net_perf), req->oldlen)));
+}