]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/netinet/ip_output.c
xnu-1504.15.3.tar.gz
[apple/xnu.git] / bsd / netinet / ip_output.c
index c065797e73441f6bc823ffbbb070fb48abb4a16e..07d74f97fbda3a7eaa03630f62400b5c7da0ccb7 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
 #include <kern/locks.h>
 #include <sys/sysctl.h>
 
+#include <machine/endian.h>
+
 #include <net/if.h>
+#include <net/if_dl.h>
 #include <net/route.h>
 
 #include <netinet/in.h>
 #include <netinet/ip_dummynet.h>
 #endif
 
+#if PF
+#include <net/pfvar.h>
+#endif /* PF */
+
 #if IPFIREWALL_FORWARD_DEBUG
 #define print_ip(a)     printf("%ld.%ld.%ld.%ld",(ntohl(a.s_addr)>>24)&0xFF,\
                                                  (ntohl(a.s_addr)>>16)&0xFF,\
@@ -145,6 +152,8 @@ static int  ip_pcbopts(int, struct mbuf **, struct mbuf *);
 static int     ip_setmoptions(struct sockopt *, struct ip_moptions **);
 
 static void ip_out_cksum_stats(int, u_int32_t);
+static struct ifaddr *in_selectsrcif(struct ip *, struct route *, unsigned int);
+static void ip_bindif(struct inpcb *, unsigned int);
 
 int ip_createmoptions(struct ip_moptions **imop);
 int ip_addmembership(struct ip_moptions *imo, struct ip_mreq *mreq);
@@ -155,8 +164,6 @@ void in_cksum_offset(struct mbuf* , size_t );
 
 extern int (*fr_checkp)(struct ip *, int, struct ifnet *, int, struct mbuf **);
 
-extern u_long  route_generation;
-
 extern struct protosw inetsw[];
 
 extern struct ip_linklocal_stat ip_linklocal_stat;
@@ -175,6 +182,11 @@ static int forge_ce = 0;
 SYSCTL_INT(_net_inet_ip, OID_AUTO, forge_ce, CTLFLAG_RW,
     &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,
+    &ip_select_srcif_debug, 0, "log source interface selection debug info");
+
 /*
  * IP output.  The packet in mbuf chain m contains a skeletal IP
  * header (with len, off, ttl, proto, tos, src, dst).
@@ -188,10 +200,10 @@ ip_output(
        struct route *ro,
        int flags,
        struct ip_moptions *imo,
-       struct ifnet *ifp)
+       struct ip_out_args *ipoa)
 {
        int error;
-       error = ip_output_list(m0, 0, opt, ro, flags, imo, ifp);
+       error = ip_output_list(m0, 0, opt, ro, flags, imo, ipoa);
        return error;
 }
 
@@ -225,20 +237,16 @@ ip_output_list(
        struct route *ro,
        int flags,
        struct ip_moptions *imo,
-#if CONFIG_FORCE_OUT_IFP
-       struct ifnet *pdp_ifp
-#else
-       __unused struct ifnet *unused_ifp
-#endif
+       struct ip_out_args *ipoa
        )
 {
-       struct ip *ip, *mhip;
+       struct ip *ip;
        struct ifnet *ifp = NULL;
-       struct mbuf *m = m0;
+       struct mbuf *m = m0, **mppn = NULL;
        int hlen = sizeof (struct ip);
        int len = 0, off, error = 0;
        struct sockaddr_in *dst = NULL;
-       struct in_ifaddr *ia = NULL;
+       struct in_ifaddr *ia = NULL, *src_ia = NULL;
        int isbroadcast, sw_csum;
        struct in_addr pkt_dst;
 #if IPSEC
@@ -249,67 +257,81 @@ ip_output_list(
 #if IPFIREWALL_FORWARD
        int fwd_rewrite_src = 0;
 #endif
+#if IPFIREWALL
        struct ip_fw_args args;
+#endif
        int didfilter = 0;
        ipfilter_t inject_filter_ref = 0;
        struct m_tag    *tag;
        struct route    saved_route;
+       struct ip_out_args saved_ipoa;
        struct mbuf * packetlist;
-       int pktcnt = 0;
-       
+       int pktcnt = 0, tso = 0;
+       unsigned int ifscope;
+       boolean_t select_srcif;
 
        KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
 
        packetlist = m0;
-       args.next_hop = NULL;
 #if IPFIREWALL
+       args.next_hop = NULL;
        args.eh = NULL;
        args.rule = NULL;
        args.divert_rule = 0;                   /* divert cookie */
-       
+       args.ipoa = NULL;
+
+       if (SLIST_EMPTY(&m0->m_pkthdr.tags))
+               goto ipfw_tags_done;
+
        /* Grab info from mtags prepended to the chain */
 #if DUMMYNET
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DUMMYNET, NULL)) != NULL) {
                struct dn_pkt_tag       *dn_tag;
-               
+
                dn_tag = (struct dn_pkt_tag *)(tag+1);
                args.rule = dn_tag->rule;
                opt = NULL;
                saved_route = dn_tag->ro;
                ro = &saved_route;
-                       
+
                imo = NULL;
                dst = dn_tag->dn_dst;
                ifp = dn_tag->ifp;
                flags = dn_tag->flags;
-               
+               saved_ipoa = dn_tag->ipoa;
+               ipoa = &saved_ipoa;
+
                m_tag_delete(m0, tag);
        }
 #endif /* DUMMYNET */
 
 #if IPDIVERT
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_DIVERT, NULL)) != NULL) {
                struct divert_tag       *div_tag;
-               
+
                div_tag = (struct divert_tag *)(tag+1);
                args.divert_rule = div_tag->cookie;
 
                m_tag_delete(m0, tag);
        }
 #endif /* IPDIVERT */
-#endif /* IPFIREWALL */
 
-       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
+       if ((tag = m_tag_locate(m0, KERNEL_MODULE_TAG_ID,
+           KERNEL_TAG_TYPE_IPFORWARD, NULL)) != NULL) {
                struct ip_fwd_tag       *ipfwd_tag;
-               
+
                ipfwd_tag = (struct ip_fwd_tag *)(tag+1);
                args.next_hop = ipfwd_tag->next_hop;
-               
+
                m_tag_delete(m0, tag);
        }
+ipfw_tags_done:
+#endif /* IPFIREWALL */
 
        m = m0;
-       
+
 #if    DIAGNOSTIC
        if ( !m || (m->m_flags & M_PKTHDR) != 0)
                panic("ip_output no HDR");
@@ -318,23 +340,38 @@ ip_output_list(
                      mtod(m, struct ip *)->ip_p);
 #endif
 
+       /*
+        * 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_ifscope;
+       } else {
+               select_srcif = FALSE;
+               ifscope = IFSCOPE_NONE;
+       }
+
 #if IPFIREWALL
        if (args.rule != NULL) {        /* dummynet already saw us */
-            ip = mtod(m, struct ip *);
-            hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
-           lck_mtx_lock(rt_mtx);
-            if (ro->ro_rt != NULL) 
-                ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
-           if (ia)
-               ifaref(&ia->ia_ifa);
-           lck_mtx_unlock(rt_mtx);
+               ip = mtod(m, struct ip *);
+               hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
+               if (ro->ro_rt != NULL) {
+                       RT_LOCK_SPIN(ro->ro_rt);
+                       ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
+                       if (ia)
+                               ifaref(&ia->ia_ifa);
+                       RT_UNLOCK(ro->ro_rt);
+               }
 #if IPSEC
-           if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-               so = ipsec_getsocket(m);
-               (void)ipsec_setsocket(m, NULL);
+               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
+                       so = ipsec_getsocket(m);
+                       (void)ipsec_setsocket(m, NULL);
                }
 #endif
-            goto sendit;
+               goto sendit;
        }
 #endif /* IPFIREWALL */
 
@@ -349,14 +386,21 @@ loopit:
         * No need to proccess packet twice if we've 
         * already seen it
         */
-       inject_filter_ref = ipf_get_inject_filter(m);
+       if (!SLIST_EMPTY(&m->m_pkthdr.tags))
+               inject_filter_ref = ipf_get_inject_filter(m);
+       else
+               inject_filter_ref = 0;
 
        if (opt) {
                m = ip_insertoptions(m, opt, &len);
                hlen = len;
        }
        ip = mtod(m, struct ip *);
+#if IPFIREWALL
        pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
+#else
+       pkt_dst = ip->ip_dst;
+#endif
 
        /*
         * Fill in IP header.
@@ -369,7 +413,7 @@ loopit:
 #else
                ip->ip_id = htons(ip_id++);
 #endif
-               OSAddAtomic(1, (SInt32*)&ipstat.ips_localout);
+               OSAddAtomic(1, &ipstat.ips_localout);
        } else {
                hlen = IP_VHL_HL(ip->ip_vhl) << 2;
        }
@@ -397,23 +441,36 @@ loopit:
         * cache with IPv6.
         */
 
-       lck_mtx_lock(rt_mtx);
        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) &&
-                   (ifa_foraddr(ip->ip_src.s_addr) == 0)) {
-                       error = EADDRNOTAVAIL;
-                       lck_mtx_unlock(rt_mtx);
-                       goto bad;
+                   (ip->ip_src.s_addr != INADDR_ANY)) {
+                       src_ia = ifa_foraddr(ip->ip_src.s_addr);
+                       if (src_ia == NULL) {
+                               error = EADDRNOTAVAIL;
+                               goto bad;
+                       }
+                       ifafree(&src_ia->ia_ifa);
                }
+               /*
+                * Test rt_flags without holding rt_lock for performance
+                * reasons; if the route is down it will hopefully be
+                * caught by the layer below (since it uses this route
+                * as a hint) or during the next transmit.
+                */
                if ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
                    dst->sin_family != AF_INET ||
                    dst->sin_addr.s_addr != pkt_dst.s_addr) {
-                       rtfree_locked(ro->ro_rt);
+                       rtfree(ro->ro_rt);
                        ro->ro_rt = NULL;
                }
-               if (ro->ro_rt && ro->ro_rt->generation_id != route_generation)
+               /*
+                * If we're doing source interface selection, we may not
+                * want to use this route; only synch up the generation
+                * count otherwise.
+                */
+               if (!select_srcif && ro->ro_rt != NULL &&
+                   ro->ro_rt->generation_id != route_generation)
                        ro->ro_rt->generation_id = route_generation;
        }
        if (ro->ro_rt == NULL) {
@@ -433,31 +490,82 @@ loopit:
                        ifafree(&ia->ia_ifa);
                if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0) {
                        if ((ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
-                               OSAddAtomic(1, (SInt32*)&ipstat.ips_noroute);
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
-                               lck_mtx_unlock(rt_mtx);
                                goto bad;
                        }
                }
                ifp = ia->ia_ifp;
                ip->ip_ttl = 1;
                isbroadcast = in_broadcast(dst->sin_addr, ifp);
+       } else if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) &&
+           imo != NULL && imo->imo_multicast_ifp != NULL) {
+               /*
+                * Bypass the normal routing lookup for multicast
+                * packets if the interface is specified.
+                */
+               ifp = imo->imo_multicast_ifp;
+               isbroadcast = 0;
+               if (ia != NULL)
+                       ifafree(&ia->ia_ifa);
+
+               /* Macro takes reference on ia */
+               IFP_TO_IA(ifp, ia);
        } else {
+               boolean_t cloneok = FALSE;
+               /*
+                * Perform source interface selection; the source IP address
+                * must belong to one of the addresses of the interface used
+                * by the route.  For performance reasons, do this only if
+                * there is no route, or if the routing table has changed,
+                * or if we haven't done source interface selection on this
+                * route (for this PCB instance) before.
+                */
+               if (select_srcif && ip->ip_src.s_addr != INADDR_ANY &&
+                   (ro->ro_rt == NULL || !(ro->ro_rt->rt_flags & RTF_UP) ||
+                   ro->ro_rt->generation_id != route_generation ||
+                   !(ro->ro_flags & ROF_SRCIF_SELECTED))) {
+                       struct ifaddr *ifa;
 
-#if CONFIG_FORCE_OUT_IFP
-               /* Check if this packet should be forced out a specific interface */
-               if (ro->ro_rt == 0 && pdp_ifp != NULL) {
-                       pdp_context_route_locked(pdp_ifp, ro);
-                       
-                       if (ro->ro_rt == NULL) {
-                               OSAddAtomic(1, (UInt32*)&ipstat.ips_noroute);
-                               error = EHOSTUNREACH;
-                               lck_mtx_unlock(rt_mtx);
+                       /* Find the source interface */
+                       ifa = in_selectsrcif(ip, ro, ifscope);
+
+                       /*
+                        * If the source address is spoofed (in the case
+                        * of IP_RAWOUTPUT), or if this is destined for
+                        * local/loopback, just let it go out using the
+                        * interface of the route.  Otherwise, there's no
+                        * interface having such an address, so bail out.
+                        */
+                       if (ifa == NULL && !(flags & IP_RAWOUTPUT) &&
+                           ifscope != lo_ifp->if_index) {
+                               error = EADDRNOTAVAIL;
                                goto bad;
                        }
+
+                       /*
+                        * If the caller didn't explicitly specify the scope,
+                        * pick it up from the source interface.  If the cached
+                        * route was wrong and was blown away as part of source
+                        * interface selection, don't mask out RTF_PRCLONING
+                        * since that route may have been allocated by the ULP,
+                        * unless the IP header was created by the caller or
+                        * the destination is IPv4 LLA.  The check for the
+                        * latter is needed because IPv4 LLAs are never scoped
+                        * in the current implementation, and we don't want to
+                        * replace the resolved IPv4 LLA route with one whose
+                        * gateway points to that of the default gateway on
+                        * the primary interface of the system.
+                        */
+                       if (ifa != NULL) {
+                               if (ifscope == IFSCOPE_NONE)
+                                       ifscope = ifa->ifa_ifp->if_index;
+                               ifafree(ifa);
+                               cloneok = (!(flags & IP_RAWOUTPUT) &&
+                                   !(IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))));
+                       }
                }
-#endif
-               
+
                /*
                 * If this is the case, we probably don't want to allocate
                 * a protocol-cloned route since we didn't get one from the
@@ -467,8 +575,7 @@ loopit:
                 * the link layer, as this is probably required in all cases
                 * for correct operation (as it is for ARP).
                 */
-               
-               if (ro->ro_rt == 0) {
+               if (ro->ro_rt == NULL) {
                        unsigned long ign = RTF_PRCLONING;
                        /*
                         * We make an exception here: if the destination
@@ -481,25 +588,40 @@ loopit:
                         * that allocate a route and those that don't.  The
                         * RTF_BROADCAST route is important since we'd want
                         * to send out undirected IP broadcast packets using
-                        * link-level broadcast address.
+                        * link-level broadcast address. Another exception
+                        * is for ULP-created routes that got blown away by
+                        * source interface selection (see above).
                         *
-                        * This exception will no longer be necessary when
+                        * These exceptions will no longer be necessary when
                         * the RTF_PRCLONING scheme is no longer present.
                         */
-                       if (dst->sin_addr.s_addr == INADDR_BROADCAST)
+                       if (cloneok || dst->sin_addr.s_addr == INADDR_BROADCAST)
                                ign &= ~RTF_PRCLONING;
 
-                       rtalloc_ign_locked(ro, ign);
+                       /*
+                        * Loosen the route lookup criteria if the ifscope
+                        * corresponds to the loopback interface; this is
+                        * needed to support Application Layer Gateways
+                        * listening on loopback, in conjunction with packet
+                        * filter redirection rules.  The final source IP
+                        * address will be rewritten by the packet filter
+                        * prior to the RFC1122 loopback check below.
+                        */
+                       if (ifscope == lo_ifp->if_index)
+                               rtalloc_ign(ro, ign);
+                       else
+                               rtalloc_scoped_ign(ro, ign, ifscope);
                }
-               if (ro->ro_rt == 0) {
-                       OSAddAtomic(1, (SInt32*)&ipstat.ips_noroute);
+
+               if (ro->ro_rt == NULL) {
+                       OSAddAtomic(1, &ipstat.ips_noroute);
                        error = EHOSTUNREACH;
-                       lck_mtx_unlock(rt_mtx);
                        goto bad;
                }
-               
+
                if (ia)
                        ifafree(&ia->ia_ifa);
+               RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
                if (ia)
                        ifaref(&ia->ia_ifa);
@@ -507,12 +629,16 @@ loopit:
                ro->ro_rt->rt_use++;
                if (ro->ro_rt->rt_flags & RTF_GATEWAY)
                        dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
-               if (ro->ro_rt->rt_flags & RTF_HOST)
+               if (ro->ro_rt->rt_flags & RTF_HOST) {
                        isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
-               else
+               } else {
+                       /* Become a regular mutex */
+                       RT_CONVERT_LOCK(ro->ro_rt);
                        isbroadcast = in_broadcast(dst->sin_addr, ifp);
+               }
+               RT_UNLOCK(ro->ro_rt);
        }
-       lck_mtx_unlock(rt_mtx);
+
        if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
                struct in_multi *inm;
 
@@ -544,7 +670,7 @@ loopit:
                 */
                if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
                        if ((ifp->if_flags & IFF_MULTICAST) == 0) {
-                               OSAddAtomic(1, (SInt32*)&ipstat.ips_noroute);
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = ENETUNREACH;
                                goto bad;
                        }
@@ -554,15 +680,14 @@ loopit:
                 * of outgoing interface.
                 */
                if (ip->ip_src.s_addr == INADDR_ANY) {
-                       register struct in_ifaddr *ia1;
-                       lck_mtx_lock(rt_mtx);   
+                       struct in_ifaddr *ia1;
+                       lck_rw_lock_shared(in_ifaddr_rwlock);
                        TAILQ_FOREACH(ia1, &in_ifaddrhead, ia_link)
                                if (ia1->ia_ifp == ifp) {
                                        ip->ip_src = IA_SIN(ia1)->sin_addr;
-                                       
                                        break;
                                }
-                       lck_mtx_unlock(rt_mtx); 
+                       lck_rw_done(in_ifaddr_rwlock);
                        if (ip->ip_src.s_addr == INADDR_ANY) {
                                error = ENETUNREACH;
                                goto bad;
@@ -594,9 +719,12 @@ loopit:
                                ipf_ref();
                                
                                /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
                                HTONS(ip->ip_len);
                                HTONS(ip->ip_off);
-                               
+#endif
+
                                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                                        if (seen == 0) {
                                                if ((struct ipfilter *)inject_filter_ref == filter)
@@ -617,9 +745,12 @@ 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;
                        }
@@ -714,6 +845,29 @@ loopit:
        }
 
 sendit:
+#if PF
+       /* Invoke outbound packet filter */
+       if (pf_af_hook(ifp, mppn, &m, AF_INET, FALSE) != 0) {
+               if (packetlist == m0) {
+                       packetlist = m;
+                       mppn = NULL;
+               }
+               if (m != NULL) {
+                       m0 = m;
+                       /* Next packet in the chain */
+                       goto loopit;
+               } else if (packetlist != NULL) {
+                       /* No more packet; send down the chain */
+                       goto sendchain;
+               }
+               /* Nothing left; we're done */
+               goto done;
+       }
+       m0 = m;
+       ip = mtod(m, struct ip *);
+       pkt_dst = ip->ip_dst;
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+#endif /* PF */
         /*
          * Force IP TTL to 255 following draft-ietf-zeroconf-ipv4-linklocal.txt
          */
@@ -728,13 +882,25 @@ sendit:
        if (!didfilter && !TAILQ_EMPTY(&ipv4_filters)) {
                struct ipfilter *filter;
                int seen = (inject_filter_ref == 0);
-               
+       
+               /* Check that a TSO frame isn't passed to a filter.
+                * This could happen if a filter is inserted while
+                * TCP is sending the TSO packet.
+                */
+               if (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) {
+                       error = EMSGSIZE;
+                       goto bad;
+               }
+
                ipf_ref();
                
                /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(ip->ip_len);
                HTONS(ip->ip_off);
-               
+#endif
+
                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                        if (seen == 0) {
                                if ((struct ipfilter *)inject_filter_ref == filter)
@@ -755,9 +921,12 @@ 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();
        }
 
@@ -836,8 +1005,11 @@ sendit:
                m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
 
+
+#if BYTE_ORDER != BIG_ENDIAN
        HTONS(ip->ip_len);
        HTONS(ip->ip_off);
+#endif
 
        error = ipsec4_output(&state, sp, flags);
     
@@ -888,53 +1060,71 @@ sendit:
        hlen = ip->ip_hl << 2;
 #endif
        /* Check that there wasn't a route change and src is still valid */
-
-       lck_mtx_lock(rt_mtx);
-       if (ro->ro_rt && ro->ro_rt->generation_id != route_generation) {
-               if (ifa_foraddr(ip->ip_src.s_addr) == 0 && ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0)) {
-                       error = EADDRNOTAVAIL;
-                       lck_mtx_unlock(rt_mtx);
-                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 5,0,0,0,0);
+       if (ro->ro_rt != NULL && ro->ro_rt->generation_id != route_generation) {
+               if ((src_ia = ifa_foraddr(ip->ip_src.s_addr)) == NULL &&
+                   ((flags & (IP_ROUTETOIF | IP_FORWARDING)) == 0)) {
+                       error = EADDRNOTAVAIL;
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                           5,0,0,0,0);
                        goto bad;
                }
-               rtfree_locked(ro->ro_rt);
+               rtfree(ro->ro_rt);
                ro->ro_rt = NULL;
+               if (src_ia != NULL)
+                       ifafree(&src_ia->ia_ifa);
        }
 
        if (ro->ro_rt == NULL) {
                if ((flags & IP_ROUTETOIF) == 0) {
-                       printf("ip_output: "
-                               "can't update route after IPsec processing\n");
-                       error = EHOSTUNREACH;   /*XXX*/ 
-                       lck_mtx_unlock(rt_mtx);
-                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 6,0,0,0,0);
+                       printf("ip_output: can't update route after "
+                           "IPsec processing\n");
+                       error = EHOSTUNREACH;   /*XXX*/
+                       KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END,
+                           6,0,0,0,0);
                        goto bad;
                }
        } else {
                if (ia)
                        ifafree(&ia->ia_ifa);
+               RT_LOCK_SPIN(ro->ro_rt);
                ia = ifatoia(ro->ro_rt->rt_ifa);
                if (ia)
                        ifaref(&ia->ia_ifa);
                ifp = ro->ro_rt->rt_ifp;
+               RT_UNLOCK(ro->ro_rt);
        }
-       lck_mtx_unlock(rt_mtx);
 
        /* make it flipped, again. */
+
+#if BYTE_ORDER != BIG_ENDIAN
        NTOHS(ip->ip_len);
        NTOHS(ip->ip_off);
+#endif
+       
        KERNEL_DEBUG(DBG_FNC_IPSEC4_OUTPUT | DBG_FUNC_END, 7,0xff,0xff,0xff,0xff);
        
        /* Pass to filters again */
        if (!TAILQ_EMPTY(&ipv4_filters)) {
                struct ipfilter *filter;
                
+               /* Check that a TSO frame isn't passed to a filter.
+                * This could happen if a filter is inserted while
+                * TCP is sending the TSO packet.
+                */
+               if (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4) {
+                       error = EMSGSIZE;
+                       goto bad;
+               }
+
                ipf_ref();
                
                /* 4135317 - always pass network byte order to filter */
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(ip->ip_len);
                HTONS(ip->ip_off);
-               
+#endif
+
                TAILQ_FOREACH(filter, &ipv4_filters, ipf_link) {
                        if (filter->ipf_filter.ipf_output) {
                                errno_t result;
@@ -952,9 +1142,12 @@ 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:
@@ -1019,22 +1212,24 @@ skip_ipsec:
                }
 #if DUMMYNET
                 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG) != 0) {
-                    /*
-                     * pass the pkt to dummynet. Need to include
-                     * pipe number, m, ifp, ro, dst because these are
-                     * not recomputed in the next pass.
-                     * All other parameters have been already used and
-                     * so they are not needed anymore. 
-                     * XXX note: if the ifp or ro entry are deleted
-                     * while a pkt is in dummynet, we are in trouble!
-                     */ 
-                   args.ro = ro;
-                   args.dst = dst;
-                   args.flags = flags;
-
-                   error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
-                               &args);
-                   goto done;
+                       /*
+                        * pass the pkt to dummynet. Need to include
+                        * pipe number, m, ifp, ro, dst because these are
+                        * not recomputed in the next pass.
+                        * All other parameters have been already used and
+                        * so they are not needed anymore.
+                        * XXX note: if the ifp or ro entry are deleted
+                        * while a pkt is in dummynet, we are in trouble!
+                        */
+                       args.ro = ro;
+                       args.dst = dst;
+                       args.flags = flags;
+                       if (flags & IP_OUTARGS)
+                               args.ipoa = ipoa;
+
+                       error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
+                           &args);
+                       goto done;
                }
 #endif /* DUMMYNET */
 #if IPDIVERT
@@ -1055,8 +1250,11 @@ skip_ipsec:
                        }
 
                        /* Restore packet header fields to original values */
+
+#if BYTE_ORDER != BIG_ENDIAN
                        HTONS(ip->ip_len);
                        HTONS(ip->ip_off);
+#endif
 
                        /* Deliver packet to divert input routine */
                        divert_packet(m, 0, off & 0xffff, args.divert_rule);
@@ -1105,6 +1303,7 @@ skip_ipsec:
                         * as the packet runs through ip_input() as
                         * it is done through a ISR.
                         */
+                       lck_rw_lock_shared(in_ifaddr_rwlock);
                        TAILQ_FOREACH(ia_fw, &in_ifaddrhead, ia_link) {
                                /*
                                 * If the addr to forward to is one
@@ -1115,13 +1314,15 @@ skip_ipsec:
                                                 dst->sin_addr.s_addr)
                                        break;
                        }
-                       if (ia) {
+                       lck_rw_done(in_ifaddr_rwlock);
+                       if (ia_fw) {
                                /* tell ip_input "dont filter" */
                                struct m_tag            *fwd_tag;
                                struct ip_fwd_tag       *ipfwd_tag;
                                
-                               fwd_tag = m_tag_alloc(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_IPFORWARD,
-                                               sizeof(struct sockaddr_in), M_NOWAIT);
+                               fwd_tag = m_tag_alloc(KERNEL_MODULE_TAG_ID,
+                                   KERNEL_TAG_TYPE_IPFORWARD,
+                                   sizeof (*ipfwd_tag), M_NOWAIT);
                                if (fwd_tag == NULL) {
                                        error = ENOBUFS;
                                        goto bad;
@@ -1150,9 +1351,11 @@ skip_ipsec:
                                        m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
                                        ip->ip_sum = in_cksum(m, hlen);
                                }
+
+#if BYTE_ORDER != BIG_ENDIAN
                                HTONS(ip->ip_len);
                                HTONS(ip->ip_off);
-                               
+#endif                         
                                
                                /*  we need to call dlil_output to run filters
                                 *      and resync to avoid recursion loops.
@@ -1173,39 +1376,46 @@ skip_ipsec:
                         */
                        bcopy(dst, &ro_fwd->ro_dst, sizeof(*dst));
 
-                       ro_fwd->ro_rt = 0;
-                       lck_mtx_lock(rt_mtx);
-                       rtalloc_ign_locked(ro_fwd, RTF_PRCLONING);
+                       ro_fwd->ro_rt = NULL;
+                       rtalloc_ign(ro_fwd, RTF_PRCLONING);
 
-                       if (ro_fwd->ro_rt == 0) {
-                               OSAddAtomic(1, (SInt32*)&ipstat.ips_noroute);
+                       if (ro_fwd->ro_rt == NULL) {
+                               OSAddAtomic(1, &ipstat.ips_noroute);
                                error = EHOSTUNREACH;
-                               lck_mtx_unlock(rt_mtx);
                                goto bad;
                        }
 
+                       RT_LOCK_SPIN(ro_fwd->ro_rt);
                        ia_fw = ifatoia(ro_fwd->ro_rt->rt_ifa);
+                       if (ia_fw != NULL)
+                               ifaref(&ia_fw->ia_ifa);
                        ifp = ro_fwd->ro_rt->rt_ifp;
                        ro_fwd->ro_rt->rt_use++;
                        if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
                                dst = (struct sockaddr_in *)ro_fwd->ro_rt->rt_gateway;
-                       if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
+                       if (ro_fwd->ro_rt->rt_flags & RTF_HOST) {
                                isbroadcast =
                                    (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
-                       else
+                       } else {
+                               /* Become a regular mutex */
+                               RT_CONVERT_LOCK(ro_fwd->ro_rt);
                                isbroadcast = in_broadcast(dst->sin_addr, ifp);
-                       rtfree_locked(ro->ro_rt);
+                       }
+                       RT_UNLOCK(ro_fwd->ro_rt);
+                       rtfree(ro->ro_rt);
                        ro->ro_rt = ro_fwd->ro_rt;
                        dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
-                       lck_mtx_unlock(rt_mtx);
 
                        /*
                         * If we added a default src ip earlier,
                         * which would have been gotten from the-then
                         * interface, do it again, from the new one.
                         */
-                       if (fwd_rewrite_src)
-                               ip->ip_src = IA_SIN(ia_fw)->sin_addr;
+                       if (ia_fw != NULL) {
+                               if (fwd_rewrite_src)
+                                       ip->ip_src = IA_SIN(ia_fw)->sin_addr;
+                               ifafree(&ia_fw->ia_ifa);
+                       }
                        goto pass ;
                }
 #endif /* IPFIREWALL_FORWARD */
@@ -1225,7 +1435,7 @@ pass:
        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)) {
-               OSAddAtomic(1, (SInt32*)&ipstat.ips_badaddr);
+               OSAddAtomic(1, &ipstat.ips_badaddr);
                m_freem(m);
                /* 
                 * Do not simply drop the packet just like a firewall -- we want the 
@@ -1239,6 +1449,8 @@ pass:
        }
 #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);
 
@@ -1284,12 +1496,17 @@ pass:
         * If small enough for interface, or the interface will take
         * care of the fragmentation for us, can just send directly.
         */
-       if ((u_short)ip->ip_len <= ifp->if_mtu ||
+       if ((u_short)ip->ip_len <= ifp->if_mtu || tso ||
            ifp->if_hwassist & CSUM_FRAGMENT) {
-               struct rtentry *rte;
+               if (tso) 
+                       m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4;
+                       
 
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(ip->ip_len);
                HTONS(ip->ip_off);
+#endif
+               
                ip->ip_sum = 0;
                if (sw_csum & CSUM_DELAY_IP) {
                        ip->ip_sum = in_cksum(m, hlen);
@@ -1309,30 +1526,22 @@ pass:
                        ipsec_delaux(m);
 #endif
                if (packetchain == 0) {
-                       lck_mtx_lock(rt_mtx);
-                       if ((rte = ro->ro_rt) != NULL)
-                               rtref(rte);
-                       lck_mtx_unlock(rt_mtx);
-                       error = ifnet_output(ifp, PF_INET, m, rte,
+                       error = ifnet_output(ifp, PF_INET, m, ro->ro_rt,
                            (struct sockaddr *)dst);
-                       if (rte != NULL)
-                               rtfree(rte);
                        goto done;
                }
                else { /* packet chaining allows us to reuse the route for all packets */
+                       mppn = &m->m_nextpkt;
                        m = m->m_nextpkt;
                        if (m == NULL) {
+#if PF
+sendchain:
+#endif /* PF */
                                if (pktcnt > ip_maxchainsent)
                                        ip_maxchainsent = pktcnt;
-                               lck_mtx_lock(rt_mtx);
-                               if ((rte = ro->ro_rt) != NULL)
-                                       rtref(rte);
-                               lck_mtx_unlock(rt_mtx);
                                //send
                                error = ifnet_output(ifp, PF_INET, packetlist,
-                                   rte, (struct sockaddr *)dst);
-                               if (rte != NULL)
-                                       rtfree(rte);
+                                   ro->ro_rt, (struct sockaddr *)dst);
                                pktcnt = 0;
                                goto done;
        
@@ -1346,32 +1555,111 @@ pass:
         * Too large for interface; fragment if possible.
         * Must be able to put at least 8 bytes per fragment.
         */
-       if (ip->ip_off & IP_DF) {
+
+       if (ip->ip_off & IP_DF  || (m->m_pkthdr.csum_flags & CSUM_TSO_IPV4)) {
                error = EMSGSIZE;
                /*
                 * This case can happen if the user changed the MTU
+                *   
                 * of an interface after enabling IP on it.  Because
                 * most netifs don't keep track of routes pointing to
                 * them, there is no way for one to update all its
                 * routes when the MTU is changed.
                 */
-               
-               lck_mtx_lock(rt_mtx);
+               RT_LOCK_SPIN(ro->ro_rt);
                if (ro->ro_rt && (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;
                }
-               lck_mtx_unlock(rt_mtx);
-               OSAddAtomic(1, (SInt32*)&ipstat.ips_cantfrag);
+               RT_UNLOCK(ro->ro_rt);
+               OSAddAtomic(1, &ipstat.ips_cantfrag);
                goto bad;
        }
-       len = (ifp->if_mtu - hlen) &~ 7;
-       if (len < 8) {
-               error = EMSGSIZE;
+
+       error = ip_fragment(m, ifp, ifp->if_mtu, sw_csum);
+       if (error != 0) {
+               m0 = m = NULL;
                goto bad;
        }
 
+       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
+                    ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
+
+       for (m = m0; m; m = m0) {
+               m0 = m->m_nextpkt;
+               m->m_nextpkt = 0;
+#if IPSEC
+               /* clean ipsec history once it goes out of the node */
+               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0)
+                       ipsec_delaux(m);
+#endif
+               if (error == 0) {
+#ifndef __APPLE__
+                       /* Record statistics for this interface address. */
+                       if (ia != NULL) {
+                               ia->ia_ifa.if_opackets++;
+                               ia->ia_ifa.if_obytes += m->m_pkthdr.len;
+                       }
+#endif
+                       if ((packetchain != 0)  && (pktcnt > 0))
+                               panic("ip_output: mix of packet in packetlist is wrong=%p", packetlist);
+                       error = ifnet_output(ifp, PF_INET, m, ro->ro_rt,
+                           (struct sockaddr *)dst);
+               } else
+                       m_freem(m);
+       }
+
+       if (error == 0)
+               OSAddAtomic(1, &ipstat.ips_fragmented);
+
+done:
+       if (ia) {
+               ifafree(&ia->ia_ifa);
+               ia = NULL;
+       }
+#if IPSEC
+       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
+       if (ro == &iproute && ro->ro_rt) {
+               rtfree(ro->ro_rt);
+               ro->ro_rt = NULL;
+       }
+       if (sp != NULL) {
+               KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
+                       printf("DP ip_output call free SP:%x\n", sp));
+               key_freesp(sp, KEY_SADB_UNLOCKED);
+       }
+       }
+#endif /* IPSEC */
+
+       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error,0,0,0,0);
+       return (error);
+bad:
+       m_freem(m0);
+       goto done;
+}
+
+int
+ip_fragment(struct mbuf *m, struct ifnet *ifp, unsigned long mtu, int sw_csum)
+{
+       struct ip *ip, *mhip;
+       int len, hlen, mhlen, firstlen, off, error = 0;
+       struct mbuf **mnext = &m->m_nextpkt, *m0;
+       int nfrags = 1;
+
+       ip = mtod(m, struct ip *);
+#ifdef _IP_VHL
+       hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+#else
+       hlen = ip->ip_hl << 2;
+#endif
+
+       firstlen = len = (mtu - hlen) &~ 7;
+       if (len < 8) {
+               m_freem(m);
+               return (EMSGSIZE);
+       }
+
        /*
         * if the interface will not calculate checksums on
         * fragmented packets, then do it here.
@@ -1382,12 +1670,6 @@ pass:
                m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
        }
 
-
-    {
-       int mhlen, firstlen = len;
-       struct mbuf **mnext = &m->m_nextpkt;
-       int nfrags = 1;
-
        /*
         * Loop through length of segment after first fragment,
         * make new header and copy data of each part and link onto chain.
@@ -1398,7 +1680,7 @@ pass:
                MGETHDR(m, M_DONTWAIT, MT_HEADER);      /* MAC-OK */
                if (m == 0) {
                        error = ENOBUFS;
-                       OSAddAtomic(1, (SInt32*)&ipstat.ips_odropped);
+                       OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
                }
                m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
@@ -1422,7 +1704,7 @@ pass:
                if (m->m_next == 0) {
                        (void) m_free(m);
                        error = ENOBUFS;        /* ??? */
-                       OSAddAtomic(1, (SInt32*)&ipstat.ips_odropped);
+                       OSAddAtomic(1, &ipstat.ips_odropped);
                        goto sendorfree;
                }
                m->m_pkthdr.len = mhlen + len;
@@ -1432,7 +1714,11 @@ pass:
 #if CONFIG_MACF_NET
                mac_netinet_fragment(m0, m);
 #endif
+
+#if BYTE_ORDER != BIG_ENDIAN
                HTONS(mhip->ip_off);
+#endif
+
                mhip->ip_sum = 0;
                if (sw_csum & CSUM_DELAY_IP) {
                        mhip->ip_sum = in_cksum(m, mhlen);
@@ -1441,7 +1727,7 @@ pass:
                mnext = &m->m_nextpkt;
                nfrags++;
        }
-       OSAddAtomic(nfrags, (SInt32*)&ipstat.ips_ofragments);
+       OSAddAtomic(nfrags, &ipstat.ips_ofragments);
 
        /* set first/last markers for fragment chain */
        m->m_flags |= M_LASTFRAG;
@@ -1457,74 +1743,20 @@ pass:
        m->m_pkthdr.len = hlen + firstlen;
        ip->ip_len = htons((u_short)m->m_pkthdr.len);
        ip->ip_off |= IP_MF;
+
+#if BYTE_ORDER != BIG_ENDIAN
        HTONS(ip->ip_off);
+#endif
+       
        ip->ip_sum = 0;
        if (sw_csum & CSUM_DELAY_IP) {
                ip->ip_sum = in_cksum(m, hlen);
        }
 sendorfree:
+       if (error)
+               m_freem_list(m0);
 
-       KERNEL_DEBUG(DBG_LAYER_END, ip->ip_dst.s_addr, 
-                    ip->ip_src.s_addr, ip->ip_p, ip->ip_off, ip->ip_len);
-
-       for (m = m0; m; m = m0) {
-               m0 = m->m_nextpkt;
-               m->m_nextpkt = 0;
-#if IPSEC
-               /* clean ipsec history once it goes out of the node */
-               if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0)
-                       ipsec_delaux(m);
-#endif
-               if (error == 0) {
-                       struct rtentry *rte;
-#ifndef __APPLE__
-                       /* Record statistics for this interface address. */
-                       if (ia != NULL) {
-                               ia->ia_ifa.if_opackets++;
-                               ia->ia_ifa.if_obytes += m->m_pkthdr.len;
-                       }
-#endif
-                       if ((packetchain != 0)  && (pktcnt > 0))
-                               panic("ip_output: mix of packet in packetlist is wrong=%p", packetlist);
-                       lck_mtx_lock(rt_mtx);
-                       if ((rte = ro->ro_rt) != NULL)
-                               rtref(rte);
-                       lck_mtx_unlock(rt_mtx);
-                       error = ifnet_output(ifp, PF_INET, m, rte,
-                           (struct sockaddr *)dst);
-                       if (rte != NULL)
-                               rtfree(rte);
-               } else
-                       m_freem(m);
-       }
-
-       if (error == 0)
-               OSAddAtomic(1, (SInt32*)&ipstat.ips_fragmented);
-    }
-done:
-       if (ia) {
-               ifafree(&ia->ia_ifa);
-               ia = NULL;
-       }
-#if IPSEC
-       if (ipsec_bypass == 0 && (flags & IP_NOIPSEC) == 0) {
-       if (ro == &iproute && ro->ro_rt) {
-               rtfree(ro->ro_rt);
-               ro->ro_rt = NULL;
-       }
-       if (sp != NULL) {
-               KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
-                       printf("DP ip_output call free SP:%x\n", sp));
-               key_freesp(sp, KEY_SADB_UNLOCKED);
-       }
-       }
-#endif /* IPSEC */
-
-       KERNEL_DEBUG(DBG_FNC_IP_OUTPUT | DBG_FUNC_END, error,0,0,0,0);
        return (error);
-bad:
-       m_freem(m0);
-       goto done;
 }
 
 static void
@@ -1563,7 +1795,7 @@ in_delayed_cksum_offset(struct mbuf *m0, int ip_offset)
        /* 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: %ld  off: %d\n",
+               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);
@@ -1626,7 +1858,7 @@ in_delayed_cksum_offset(struct mbuf *m0, int ip_offset)
                char tmp[2];
                
 #if DEBUG
-               printf("delayed m_copyback, m->len: %ld  off: %d  p: %d\n",
+               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;
@@ -1662,7 +1894,7 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
        if (ip_offset + sizeof(struct ip) > m->m_len) {
 
 #if DEBUG
-               printf("in_cksum_offset - delayed m_pullup, m->len: %ld  off: %lu\n",
+               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);
@@ -1726,7 +1958,7 @@ in_cksum_offset(struct mbuf* m, size_t ip_offset)
                char tmp[2];
 
 #if DEBUG
-               printf("in_cksum_offset m_copyback, m->len: %lu  off: %lu  p: %d\n",
+               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;
@@ -1862,7 +2094,8 @@ ip_ctloutput(so, sopt)
                                error = EMSGSIZE;
                                break;
                        }
-                       MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_HEADER);
+                       MGET(m, sopt->sopt_p != kernproc ? M_WAIT : M_DONTWAIT,
+                           MT_HEADER);
                        if (m == 0) {
                                error = ENOBUFS;
                                break;
@@ -1935,58 +2168,66 @@ ip_ctloutput(so, sopt)
                        break;
 #undef OPTSET
 
-#if CONFIG_FORCE_OUT_IFP               
+#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];
-                       ifnet_t ifp;
-                       
+                       char ifname[IFNAMSIZ];
+                       unsigned int ifscope;
+
+                       /* This option is settable only for IPv4 */
+                       if (!(inp->inp_vflag & INP_IPV4)) {
+                               error = EINVAL;
+                               break;
+                       }
+
                        /* Verify interface name parameter is sane */
                        if (sopt->sopt_valsize > sizeof(ifname)) {
                                error = EINVAL;
                                break;
                        }
-                       
+
                        /* Copy the interface name */
                        if (sopt->sopt_valsize != 0) {
-                               error = sooptcopyin(sopt, ifname, sizeof(ifname), sopt->sopt_valsize);
+                               error = sooptcopyin(sopt, ifname,
+                                   sizeof (ifname), sopt->sopt_valsize);
                                if (error)
                                        break;
                        }
-                       
-                       if (sopt->sopt_valsize == 0 || ifname[0] == 0) {
-                               // Set pdp_ifp to NULL
-                               inp->pdp_ifp = NULL;
-                               
-                               // Flush the route
-                               if (inp->inp_route.ro_rt) {
-                                       rtfree(inp->inp_route.ro_rt);
-                                       inp->inp_route.ro_rt = NULL;
+
+                       if (sopt->sopt_valsize == 0 || ifname[0] == NULL) {
+                               /* Unbind this socket from any interface */
+                               ifscope = IFSCOPE_NONE;
+                       } else {
+                               ifnet_t ifp;
+
+                               /* Verify name is NULL terminated */
+                               if (ifname[sopt->sopt_valsize - 1] != NULL) {
+                                       error = EINVAL;
+                                       break;
                                }
-                               
-                               break;
-                       }
-                       
-                       /* Verify name is NULL terminated */
-                       if (ifname[sopt->sopt_valsize - 1] != 0) {
-                               error = EINVAL;
-                               break;
-                       }
-                       
-                       if (ifnet_find_by_name(ifname, &ifp) != 0) {
-                               error = ENXIO;
-                               break;
-                       }
-                       
-                       /* Won't actually free. Since we don't release this later, we should do it now. */
-                       ifnet_release(ifp);
-                       
-                       /* This only works for point-to-point interfaces */
-                       if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
-                               error = ENOTSUP;
-                               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->pdp_ifp = ifp;
+                       ip_bindif(inp, ifscope);
                }
                break;
 #endif
@@ -2044,8 +2285,7 @@ ip_ctloutput(so, sopt)
                                break;
                        if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
                                break;
-                       priv = (sopt->sopt_p != NULL &&
-                               proc_suser(sopt->sopt_p) != 0) ? 0 : 1;
+                       priv = (proc_suser(sopt->sopt_p) == 0);
                        if (m) {
                                req = mtod(m, caddr_t);
                                len = m->m_len;
@@ -2065,15 +2305,54 @@ ip_ctloutput(so, sopt)
                        if (error) 
                                break;
 
-                       if (background) 
-                               so->so_traffic_mgt_flags |= TRAFFIC_MGT_SO_BACKGROUND;
-                       else 
-                               so->so_traffic_mgt_flags &= ~TRAFFIC_MGT_SO_BACKGROUND;
+                       if (background) {
+                               socket_set_traffic_mgt_flags(so,
+                                   TRAFFIC_MGT_SO_BACKGROUND |
+                                   TRAFFIC_MGT_SO_BG_REGULATE);
+                       } else {
+                               socket_clear_traffic_mgt_flags(so,
+                                   TRAFFIC_MGT_SO_BACKGROUND |
+                                   TRAFFIC_MGT_SO_BG_REGULATE);
+                       }
 
                        break;
                }
 #endif /* TRAFFIC_MGT */
 
+               /*
+                * On a multihomed system, scoped routing can be used to
+                * restrict the source interface used for sending packets.
+                * The socket option IP_BOUND_IF binds a particular AF_INET
+                * socket to an interface such that data sent on the socket
+                * is restricted to that interface.  This is unlike the
+                * SO_DONTROUTE option where the routing table is bypassed;
+                * therefore it allows for a greater flexibility and control
+                * over the system behavior, and does not place any restriction
+                * on the destination address type (e.g.  unicast, multicast,
+                * or broadcast if applicable) or whether or not the host is
+                * directly reachable.  Note that in the multicast transmit
+                * case, IP_MULTICAST_IF takes precedence over IP_BOUND_IF,
+                * since the former practically bypasses the routing table;
+                * in this case, IP_BOUND_IF sets the default interface used
+                * for sending multicast packets in the absence of an explicit
+                * transmit interface set via IP_MULTICAST_IF.
+                */
+               case IP_BOUND_IF:
+                       /* This option is settable only for IPv4 */
+                       if (!(inp->inp_vflag & INP_IPV4)) {
+                               error = EINVAL;
+                               break;
+                       }
+
+                       error = sooptcopyin(sopt, &optval, sizeof (optval),
+                           sizeof (optval));
+
+                       if (error)
+                               break;
+
+                       ip_bindif(inp, optval);
+                       break;
+
                default:
                        error = ENOPROTOOPT;
                        break;
@@ -2192,6 +2471,12 @@ ip_ctloutput(so, sopt)
                }
 #endif /* TRAFFIC_MGT */
 
+               case IP_BOUND_IF:
+                       if (inp->inp_flags & INP_BOUND_IF)
+                               optval = inp->inp_boundif;
+                       error = sooptcopyout(sopt, &optval, sizeof (optval));
+                       break;
+
                default:
                        error = ENOPROTOOPT;
                        break;
@@ -2353,7 +2638,6 @@ ip_setmoptions(sopt, imop)
        struct ip_moptions **imop;
 {
        int error = 0;
-       int i;
        struct in_addr addr;
        struct ip_mreq mreq;
        struct ifnet *ifp = NULL;
@@ -2374,20 +2658,23 @@ ip_setmoptions(sopt, imop)
        switch (sopt->sopt_name) {
        /* store an index number for the vif you wanna use in the send */
 #if MROUTING
-       case IP_MULTICAST_VIF:
-               if (legal_vif_num == 0) {
-                       error = EOPNOTSUPP;
-                       break;
-               }
-               error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
-               if (error)
-                       break;
-               if (!legal_vif_num(i) && (i != -1)) {
-                       error = EINVAL;
+       case IP_MULTICAST_VIF: 
+               {
+                       int i;
+                       if (legal_vif_num == 0) {
+                               error = EOPNOTSUPP;
+                               break;
+                       }
+                       error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
+                       if (error)
+                               break;
+                       if (!legal_vif_num(i) && (i != -1)) {
+                               error = EINVAL;
+                               break;
+                       }
+                       imo->imo_multicast_vif = i;
                        break;
                }
-               imo->imo_multicast_vif = i;
-               break;
 #endif /* MROUTING */
 
        case IP_MULTICAST_IF:
@@ -2505,7 +2792,7 @@ ip_setmoptions(sopt, imop)
         * If all options have default values, no need to keep the mbuf.
         */
        if (imo->imo_multicast_ifp == NULL &&
-           imo->imo_multicast_vif == (u_long)-1 &&
+           imo->imo_multicast_vif == (u_int32_t)-1 &&
            imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
            imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
            imo->imo_num_memberships == 0) {
@@ -2553,34 +2840,31 @@ ip_addmembership(
        struct ifnet *ifp = NULL;
        int error = 0;
        int i;
-       
+
+       bzero((caddr_t)&ro, sizeof(ro));
+
        if (!IN_MULTICAST(ntohl(mreq->imr_multiaddr.s_addr))) {
                error = EINVAL;
-               return error;
+               goto done;
        }
        /*
         * If no interface address was provided, use the interface of
         * the route to the given multicast address.
         */
        if (mreq->imr_interface.s_addr == INADDR_ANY) {
-               bzero((caddr_t)&ro, sizeof(ro));
                dst = (struct sockaddr_in *)&ro.ro_dst;
                dst->sin_len = sizeof(*dst);
                dst->sin_family = AF_INET;
                dst->sin_addr = mreq->imr_multiaddr;
-               lck_mtx_lock(rt_mtx);
-               rtalloc_ign_locked(&ro, 0UL);
+               rtalloc_ign(&ro, 0);
                if (ro.ro_rt != NULL) {
                        ifp = ro.ro_rt->rt_ifp;
-                       rtfree_locked(ro.ro_rt);
-               }
-               else {
+               } else {
                        /* If there's no default route, try using loopback */
-                       mreq->imr_interface.s_addr = INADDR_LOOPBACK;
+                       mreq->imr_interface.s_addr = htonl(INADDR_LOOPBACK);
                }
-               lck_mtx_unlock(rt_mtx);
        }
-       
+
        if (ifp == NULL) {
                ifp = ip_multicast_if(&mreq->imr_interface, NULL);
        }
@@ -2591,7 +2875,7 @@ ip_addmembership(
         */
        if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
                error = EADDRNOTAVAIL;
-               return error;
+               goto done;
        }
        /*
         * See if the membership already exists or if all the
@@ -2605,11 +2889,11 @@ ip_addmembership(
        }
        if (i < imo->imo_num_memberships) {
                error = EADDRINUSE;
-               return error;
+               goto done;
        }
        if (i == IP_MAX_MEMBERSHIPS) {
                error = ETOOMANYREFS;
-               return error;
+               goto done;
        }
        /*
         * Everything looks good; add a new record to the multicast
@@ -2618,10 +2902,14 @@ ip_addmembership(
        if ((imo->imo_membership[i] =
                in_addmulti(&mreq->imr_multiaddr, ifp)) == NULL) {
                error = ENOBUFS;
-               return error;
+               goto done;
        }
        ++imo->imo_num_memberships;
-       
+
+done:
+       if (ro.ro_rt != NULL)
+               rtfree(ro.ro_rt);
+
        return error;
 }
 
@@ -2719,6 +3007,8 @@ ip_getmoptions(sopt, imo)
                        IFP_TO_IA(imo->imo_multicast_ifp, ia);
                        addr.s_addr = (ia == NULL) ? INADDR_ANY
                                : IA_SIN(ia)->sin_addr.s_addr;
+                       if (ia != NULL)
+                               ifafree(&ia->ia_ifa);
                }
                error = sooptcopyout(sopt, &addr, sizeof addr);
                break;
@@ -2798,8 +3088,12 @@ 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);
        /*
@@ -2837,9 +3131,17 @@ ip_mloopback(ifp, m, dst, hlen)
                            CSUM_IP_CHECKED | CSUM_IP_VALID;
                        copym->m_pkthdr.csum_data = 0xffff;
                } else {
+
+#if BYTE_ORDER != BIG_ENDIAN
                        NTOHS(ip->ip_len);
+#endif
+                       
                        in_delayed_cksum(copym);
+
+#if BYTE_ORDER != BIG_ENDIAN
                        HTONS(ip->ip_len);
+#endif
+               
                }
         }
 
@@ -2864,3 +3166,309 @@ ip_mloopback(ifp, m, dst, hlen)
                m_freem(copym);
        }
 }
+
+/*
+ * Given a source IP address (and route, if available), determine the best
+ * interface to send the packet from.  Checking for (and updating) the
+ * ROF_SRCIF_SELECTED flag in the pcb-supplied route placeholder is done
+ * without any locks based on the assumption that ip_output() is single-
+ * threaded per-pcb, i.e. for any given pcb there can only be one thread
+ * performing output at the IP layer.
+ */
+static struct ifaddr *
+in_selectsrcif(struct ip *ip, struct route *ro, unsigned int ifscope)
+{
+       struct ifaddr *ifa = NULL;
+       struct in_addr src = ip->ip_src;
+       struct in_addr dst = ip->ip_dst;
+       struct ifnet *rt_ifp;
+       char s_src[MAX_IPv4_STR_LEN], s_dst[MAX_IPv4_STR_LEN];
+
+       if (ip_select_srcif_debug) {
+               (void) inet_ntop(AF_INET, &src.s_addr, s_src, sizeof (s_src));
+               (void) inet_ntop(AF_INET, &dst.s_addr, s_dst, sizeof (s_dst));
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_LOCK(ro->ro_rt);
+
+       rt_ifp = (ro->ro_rt != NULL) ? ro->ro_rt->rt_ifp : NULL;
+
+       /*
+        * Given the source IP address, find a suitable source interface
+        * to use for transmission; if the caller has specified a scope,
+        * optimize the search by looking at the addresses only for that
+        * interface.  This is still suboptimal, however, as we need to
+        * traverse the per-interface list.
+        */
+       if (ifscope != IFSCOPE_NONE || ro->ro_rt != NULL) {
+               unsigned int scope = ifscope;
+
+               /*
+                * If no scope is specified and the route is stale (pointing
+                * to a defunct interface) use the current primary interface;
+                * this happens when switching between interfaces configured
+                * with the same IP address.  Otherwise pick up the scope
+                * information from the route; the ULP may have looked up a
+                * correct route and we just need to verify it here and mark
+                * it with the ROF_SRCIF_SELECTED flag below.
+                */
+               if (scope == IFSCOPE_NONE) {
+                       scope = rt_ifp->if_index;
+                       if (scope != get_primary_ifscope() &&
+                           ro->ro_rt->generation_id != route_generation)
+                               scope = get_primary_ifscope();
+               }
+
+               ifa = (struct ifaddr *)ifa_foraddr_scoped(src.s_addr, scope);
+
+               if (ifa == NULL && ip->ip_p != IPPROTO_UDP &&
+                   ip->ip_p != IPPROTO_TCP && ipforwarding) {
+                       /*
+                        * If forwarding is enabled, and if the packet isn't
+                        * TCP or UDP, check if the source address belongs
+                        * to one of our own interfaces; if so, demote the
+                        * interface scope and do a route lookup right below.
+                        */
+                       ifa = (struct ifaddr *)ifa_foraddr(src.s_addr);
+                       if (ifa != NULL) {
+                               ifafree(ifa);
+                               ifa = NULL;
+                               ifscope = IFSCOPE_NONE;
+                       }
+               }
+
+               if (ip_select_srcif_debug && ifa != NULL) {
+                       if (ro->ro_rt != NULL) {
+                               printf("%s->%s ifscope %d->%d ifa_if %s%d "
+                                   "ro_if %s%d\n", s_src, s_dst, ifscope,
+                                   scope, ifa->ifa_ifp->if_name,
+                                   ifa->ifa_ifp->if_unit, rt_ifp->if_name,
+                                   rt_ifp->if_unit);
+                       } else {
+                               printf("%s->%s ifscope %d->%d ifa_if %s%d\n",
+                                   s_src, s_dst, ifscope, scope,
+                                   ifa->ifa_ifp->if_name,
+                                   ifa->ifa_ifp->if_unit);
+                       }
+               }
+       }
+
+       /*
+        * Slow path; search for an interface having the corresponding source
+        * IP address if the scope was not specified by the caller, and:
+        *
+        *   1) There currently isn't any route, or,
+        *   2) The interface used by the route does not own that source
+        *      IP address; in this case, the route will get blown away
+        *      and we'll do a more specific scoped search using the newly
+        *      found interface.
+        */
+       if (ifa == NULL && ifscope == IFSCOPE_NONE) {
+               ifa = (struct ifaddr *)ifa_foraddr(src.s_addr);
+
+               /*
+                * If we have the IP address, but not the route, we don't
+                * really know whether or not it belongs to the correct
+                * interface (it could be shared across multiple interfaces.)
+                * The only way to find out is to do a route lookup.
+                */
+               if (ifa != NULL && ro->ro_rt == NULL) {
+                       struct rtentry *rt;
+                       struct sockaddr_in sin;
+                       struct ifaddr *oifa = NULL;
+
+                       bzero(&sin, sizeof (sin));
+                       sin.sin_family = AF_INET;
+                       sin.sin_len = sizeof (sin);
+                       sin.sin_addr = dst;
+
+                       lck_mtx_lock(rnh_lock);
+                       if ((rt = rt_lookup(TRUE, (struct sockaddr *)&sin, NULL,
+                           rt_tables[AF_INET], IFSCOPE_NONE)) != NULL) {
+                               RT_LOCK(rt);
+                               /*
+                                * If the route uses a different interface,
+                                * use that one instead.  The IP address of
+                                * the ifaddr that we pick up here is not
+                                * relevant.
+                                */
+                               if (ifa->ifa_ifp != rt->rt_ifp) {
+                                       oifa = ifa;
+                                       ifa = rt->rt_ifa;
+                                       ifaref(ifa);
+                                       RT_UNLOCK(rt);
+                               } else {
+                                       RT_UNLOCK(rt);
+                               }
+                               rtfree_locked(rt);
+                       }
+                       lck_mtx_unlock(rnh_lock);
+
+                       if (oifa != NULL) {
+                               struct ifaddr *iifa;
+
+                               /*
+                                * See if the interface pointed to by the
+                                * route is configured with the source IP
+                                * address of the packet.
+                                */
+                               iifa = (struct ifaddr *)ifa_foraddr_scoped(
+                                   src.s_addr, ifa->ifa_ifp->if_index);
+
+                               if (iifa != NULL) {
+                                       /*
+                                        * Found it; drop the original one
+                                        * as well as the route interface
+                                        * address, and use this instead.
+                                        */
+                                       ifafree(oifa);
+                                       ifafree(ifa);
+                                       ifa = iifa;
+                               } else if (!ipforwarding ||
+                                   (rt->rt_flags & RTF_GATEWAY)) {
+                                       /*
+                                        * This interface doesn't have that
+                                        * source IP address; drop the route
+                                        * interface address and just use the
+                                        * original one, and let the caller
+                                        * do a scoped route lookup.
+                                        */
+                                       ifafree(ifa);
+                                       ifa = oifa;
+                               } else {
+                                       /*
+                                        * Forwarding is enabled and the source
+                                        * address belongs to one of our own
+                                        * interfaces which isn't the outgoing
+                                        * interface, and we have a route, and
+                                        * the destination is on a network that
+                                        * is directly attached (onlink); drop
+                                        * the original one and use the route
+                                        * interface address instead.
+                                        */
+                                       ifafree(oifa);
+                               }
+                       }
+               } else if (ifa != NULL && ro->ro_rt != NULL &&
+                   !(ro->ro_rt->rt_flags & RTF_GATEWAY) &&
+                   ifa->ifa_ifp != ro->ro_rt->rt_ifp && ipforwarding) {
+                       /*
+                        * Forwarding is enabled and the source address belongs
+                        * to one of our own interfaces which isn't the same
+                        * as the interface used by the known route; drop the
+                        * original one and use the route interface address.
+                        */
+                       ifafree(ifa);
+                       ifa = ro->ro_rt->rt_ifa;
+                       ifaref(ifa);
+               }
+
+               if (ip_select_srcif_debug && ifa != NULL) {
+                       printf("%s->%s ifscope %d ifa_if %s%d\n",
+                           s_src, s_dst, ifscope, ifa->ifa_ifp->if_name,
+                           ifa->ifa_ifp->if_unit);
+               }
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_LOCK_ASSERT_HELD(ro->ro_rt);
+       /*
+        * If there is a non-loopback route with the wrong interface, or if
+        * there is no interface configured with such an address, blow it
+        * away.  Except for local/loopback, we look for one with a matching
+        * interface scope/index.
+        */
+       if (ro->ro_rt != NULL &&
+           (ifa == NULL || (ifa->ifa_ifp != rt_ifp && rt_ifp != lo_ifp) ||
+           !(ro->ro_rt->rt_flags & RTF_UP))) {
+               if (ip_select_srcif_debug) {
+                       if (ifa != NULL) {
+                               printf("%s->%s ifscope %d ro_if %s%d != "
+                                   "ifa_if %s%d (cached route cleared)\n",
+                                   s_src, s_dst, ifscope, rt_ifp->if_name,
+                                   rt_ifp->if_unit, ifa->ifa_ifp->if_name,
+                                   ifa->ifa_ifp->if_unit);
+                       } else {
+                               printf("%s->%s ifscope %d ro_if %s%d "
+                                   "(no ifa_if found)\n",
+                                   s_src, s_dst, ifscope, rt_ifp->if_name,
+                                   rt_ifp->if_unit);
+                       }
+               }
+
+               RT_UNLOCK(ro->ro_rt);
+               rtfree(ro->ro_rt);
+               ro->ro_rt = NULL;
+               ro->ro_flags &= ~ROF_SRCIF_SELECTED;
+
+               /*
+                * If the destination is IPv4 LLA and the route's interface
+                * doesn't match the source interface, then the source IP
+                * address is wrong; it most likely belongs to the primary
+                * interface associated with the IPv4 LL subnet.  Drop the
+                * packet rather than letting it go out and return an error
+                * to the ULP.  This actually applies not only to IPv4 LL
+                * but other shared subnets; for now we explicitly test only
+                * for the former case and save the latter for future.
+                */
+               if (IN_LINKLOCAL(ntohl(dst.s_addr)) &&
+                   !IN_LINKLOCAL(ntohl(src.s_addr)) && ifa != NULL) {
+                       ifafree(ifa);
+                       ifa = NULL;
+               }
+       }
+
+       if (ip_select_srcif_debug && ifa == NULL) {
+               printf("%s->%s ifscope %d (neither ro_if/ifa_if found)\n",
+                   s_src, s_dst, ifscope);
+       }
+
+       /*
+        * If there is a route, mark it accordingly.  If there isn't one,
+        * we'll get here again during the next transmit (possibly with a
+        * route) and the flag will get set at that point.  For IPv4 LLA
+        * destination, mark it only if the route has been fully resolved;
+        * otherwise we want to come back here again when the route points
+        * to the interface over which the ARP reply arrives on.
+        */
+       if (ro->ro_rt != NULL && (!IN_LINKLOCAL(ntohl(dst.s_addr)) ||
+           (ro->ro_rt->rt_gateway->sa_family == AF_LINK &&
+           SDL(ro->ro_rt->rt_gateway)->sdl_alen != 0))) {
+               ro->ro_flags |= ROF_SRCIF_SELECTED;
+               ro->ro_rt->generation_id = route_generation;
+       }
+
+       if (ro->ro_rt != NULL)
+               RT_UNLOCK(ro->ro_rt);
+
+       return (ifa);
+}
+
+/*
+ * Handler for setting IP_FORCE_OUT_IFP or IP_BOUND_IF socket option.
+ */
+static void
+ip_bindif(struct inpcb *inp, unsigned int ifscope)
+{
+       /*
+        * A zero interface scope value indicates an "unbind".
+        * Otherwise, take in whatever value the app desires;
+        * the app may already know the scope (or force itself
+        * to such a scope) ahead of time before the interface
+        * gets attached.  It doesn't matter either way; any
+        * route lookup from this point on will require an
+        * exact match for the embedded interface scope.
+        */
+       inp->inp_boundif = ifscope;
+       if (inp->inp_boundif == IFSCOPE_NONE)
+               inp->inp_flags &= ~INP_BOUND_IF;
+       else
+               inp->inp_flags |= INP_BOUND_IF;
+
+       /* Blow away any cached route in the PCB */
+       if (inp->inp_route.ro_rt != NULL) {
+               rtfree(inp->inp_route.ro_rt);
+               inp->inp_route.ro_rt = NULL;
+       }
+}