The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet/ip_output.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1990, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)ip_output.c 8.3 (Berkeley) 1/21/94
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/8.2/sys/netinet/ip_output.c 214338 2010-10-25 13:16:11Z attilio $");
   34 
   35 #include "opt_ipfw.h"
   36 #include "opt_ipsec.h"
   37 #include "opt_route.h"
   38 #include "opt_mbuf_stress_test.h"
   39 #include "opt_mpath.h"
   40 #include "opt_sctp.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/kernel.h>
   45 #include <sys/malloc.h>
   46 #include <sys/mbuf.h>
   47 #include <sys/priv.h>
   48 #include <sys/proc.h>
   49 #include <sys/protosw.h>
   50 #include <sys/socket.h>
   51 #include <sys/socketvar.h>
   52 #include <sys/sysctl.h>
   53 #include <sys/ucred.h>
   54 
   55 #include <net/if.h>
   56 #include <net/if_llatbl.h>
   57 #include <net/netisr.h>
   58 #include <net/pfil.h>
   59 #include <net/route.h>
   60 #include <net/flowtable.h>
   61 #ifdef RADIX_MPATH
   62 #include <net/radix_mpath.h>
   63 #endif
   64 #include <net/vnet.h>
   65 
   66 #include <netinet/in.h>
   67 #include <netinet/in_systm.h>
   68 #include <netinet/ip.h>
   69 #include <netinet/in_pcb.h>
   70 #include <netinet/in_var.h>
   71 #include <netinet/ip_var.h>
   72 #include <netinet/ip_options.h>
   73 #ifdef SCTP
   74 #include <netinet/sctp.h>
   75 #include <netinet/sctp_crc32.h>
   76 #endif
   77 
   78 #ifdef IPSEC
   79 #include <netinet/ip_ipsec.h>
   80 #include <netipsec/ipsec.h>
   81 #endif /* IPSEC*/
   82 
   83 #include <machine/in_cksum.h>
   84 
   85 #include <security/mac/mac_framework.h>
   86 
   87 #define print_ip(x, a, y)        printf("%s %d.%d.%d.%d%s",\
   88                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
   89                                   (ntohl(a.s_addr)>>16)&0xFF,\
   90                                   (ntohl(a.s_addr)>>8)&0xFF,\
   91                                   (ntohl(a.s_addr))&0xFF, y);
   92 
   93 VNET_DEFINE(u_short, ip_id);
   94 
   95 #ifdef MBUF_STRESS_TEST
   96 int mbuf_frag_size = 0;
   97 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
   98         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
   99 #endif
  100 
  101 static void     ip_mloopback
  102         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
  103 
  104 
  105 extern int in_mcast_loop;
  106 extern  struct protosw inetsw[];
  107 
  108 /*
  109  * IP output.  The packet in mbuf chain m contains a skeletal IP
  110  * header (with len, off, ttl, proto, tos, src, dst).
  111  * The mbuf chain containing the packet will be freed.
  112  * The mbuf opt, if present, will not be freed.
  113  * In the IP forwarding case, the packet will arrive with options already
  114  * inserted, so must have a NULL opt pointer.
  115  */
  116 int
  117 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags,
  118     struct ip_moptions *imo, struct inpcb *inp)
  119 {
  120         struct ip *ip;
  121         struct ifnet *ifp = NULL;       /* keep compiler happy */
  122         struct mbuf *m0;
  123         int hlen = sizeof (struct ip);
  124         int mtu;
  125         int len, error = 0;
  126         int nortfree = 0;
  127         struct sockaddr_in *dst = NULL; /* keep compiler happy */
  128         struct in_ifaddr *ia = NULL;
  129         int isbroadcast, sw_csum;
  130         struct route iproute;
  131         struct rtentry *rte;    /* cache for ro->ro_rt */
  132         struct in_addr odst;
  133 #ifdef IPFIREWALL_FORWARD
  134         struct m_tag *fwd_tag = NULL;
  135 #endif
  136 #ifdef IPSEC
  137         int no_route_but_check_spd = 0;
  138 #endif
  139         M_ASSERTPKTHDR(m);
  140 
  141         if (inp != NULL) {
  142                 INP_LOCK_ASSERT(inp);
  143                 M_SETFIB(m, inp->inp_inc.inc_fibnum);
  144                 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) {
  145                         m->m_pkthdr.flowid = inp->inp_flowid;
  146                         m->m_flags |= M_FLOWID;
  147                 }
  148         }
  149 
  150         if (ro == NULL) {
  151                 ro = &iproute;
  152                 bzero(ro, sizeof (*ro));
  153 
  154 #ifdef FLOWTABLE
  155                 {
  156                         struct flentry *fle;
  157                         
  158                         /*
  159                          * The flow table returns route entries valid for up to 30
  160                          * seconds; we rely on the remainder of ip_output() taking no
  161                          * longer than that long for the stability of ro_rt.  The
  162                          * flow ID assignment must have happened before this point.
  163                          */
  164                         if ((fle = flowtable_lookup_mbuf(V_ip_ft, m, AF_INET)) != NULL) {
  165                                 flow_to_route(fle, ro);
  166                                 nortfree = 1;
  167                         }
  168                 }
  169 #endif
  170         }
  171 
  172         if (opt) {
  173                 len = 0;
  174                 m = ip_insertoptions(m, opt, &len);
  175                 if (len != 0)
  176                         hlen = len;
  177         }
  178         ip = mtod(m, struct ip *);
  179 
  180         /*
  181          * Fill in IP header.  If we are not allowing fragmentation,
  182          * then the ip_id field is meaningless, but we don't set it
  183          * to zero.  Doing so causes various problems when devices along
  184          * the path (routers, load balancers, firewalls, etc.) illegally
  185          * disable DF on our packet.  Note that a 16-bit counter
  186          * will wrap around in less than 10 seconds at 100 Mbit/s on a
  187          * medium with MTU 1500.  See Steven M. Bellovin, "A Technique
  188          * for Counting NATted Hosts", Proc. IMW'02, available at
  189          * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>.
  190          */
  191         if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
  192                 ip->ip_v = IPVERSION;
  193                 ip->ip_hl = hlen >> 2;
  194                 ip->ip_id = ip_newid();
  195                 IPSTAT_INC(ips_localout);
  196         } else {
  197                 hlen = ip->ip_hl << 2;
  198         }
  199 
  200         dst = (struct sockaddr_in *)&ro->ro_dst;
  201 again:
  202         /*
  203          * If there is a cached route,
  204          * check that it is to the same destination
  205          * and is still up.  If not, free it and try again.
  206          * The address family should also be checked in case of sharing the
  207          * cache with IPv6.
  208          */
  209         rte = ro->ro_rt;
  210         if (rte && ((rte->rt_flags & RTF_UP) == 0 ||
  211                     rte->rt_ifp == NULL ||
  212                     !RT_LINK_IS_UP(rte->rt_ifp) ||
  213                           dst->sin_family != AF_INET ||
  214                           dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
  215                 if (!nortfree)
  216                         RTFREE(rte);
  217                 rte = ro->ro_rt = (struct rtentry *)NULL;
  218                 ro->ro_lle = (struct llentry *)NULL;
  219         }
  220 #ifdef IPFIREWALL_FORWARD
  221         if (rte == NULL && fwd_tag == NULL) {
  222 #else
  223         if (rte == NULL) {
  224 #endif
  225                 bzero(dst, sizeof(*dst));
  226                 dst->sin_family = AF_INET;
  227                 dst->sin_len = sizeof(*dst);
  228                 dst->sin_addr = ip->ip_dst;
  229         }
  230         /*
  231          * If routing to interface only, short circuit routing lookup.
  232          * The use of an all-ones broadcast address implies this; an
  233          * interface is specified by the broadcast address of an interface,
  234          * or the destination address of a ptp interface.
  235          */
  236         if (flags & IP_SENDONES) {
  237                 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL &&
  238                     (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) {
  239                         IPSTAT_INC(ips_noroute);
  240                         error = ENETUNREACH;
  241                         goto bad;
  242                 }
  243                 ip->ip_dst.s_addr = INADDR_BROADCAST;
  244                 dst->sin_addr = ip->ip_dst;
  245                 ifp = ia->ia_ifp;
  246                 ip->ip_ttl = 1;
  247                 isbroadcast = 1;
  248         } else if (flags & IP_ROUTETOIF) {
  249                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
  250                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) {
  251                         IPSTAT_INC(ips_noroute);
  252                         error = ENETUNREACH;
  253                         goto bad;
  254                 }
  255                 ifp = ia->ia_ifp;
  256                 ip->ip_ttl = 1;
  257                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
  258         } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
  259             imo != NULL && imo->imo_multicast_ifp != NULL) {
  260                 /*
  261                  * Bypass the normal routing lookup for multicast
  262                  * packets if the interface is specified.
  263                  */
  264                 ifp = imo->imo_multicast_ifp;
  265                 IFP_TO_IA(ifp, ia);
  266                 isbroadcast = 0;        /* fool gcc */
  267         } else {
  268                 /*
  269                  * We want to do any cloning requested by the link layer,
  270                  * as this is probably required in all cases for correct
  271                  * operation (as it is for ARP).
  272                  */
  273                 if (rte == NULL) {
  274 #ifdef RADIX_MPATH
  275                         rtalloc_mpath_fib(ro,
  276                             ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr),
  277                             inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
  278 #else
  279                         in_rtalloc_ign(ro, 0,
  280                             inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m));
  281 #endif
  282                         rte = ro->ro_rt;
  283                 }
  284                 if (rte == NULL ||
  285                     rte->rt_ifp == NULL ||
  286                     !RT_LINK_IS_UP(rte->rt_ifp)) {
  287 #ifdef IPSEC
  288                         /*
  289                          * There is no route for this packet, but it is
  290                          * possible that a matching SPD entry exists.
  291                          */
  292                         no_route_but_check_spd = 1;
  293                         mtu = 0; /* Silence GCC warning. */
  294                         goto sendit;
  295 #endif
  296                         IPSTAT_INC(ips_noroute);
  297                         error = EHOSTUNREACH;
  298                         goto bad;
  299                 }
  300                 ia = ifatoia(rte->rt_ifa);
  301                 ifa_ref(&ia->ia_ifa);
  302                 ifp = rte->rt_ifp;
  303                 rte->rt_rmx.rmx_pksent++;
  304                 if (rte->rt_flags & RTF_GATEWAY)
  305                         dst = (struct sockaddr_in *)rte->rt_gateway;
  306                 if (rte->rt_flags & RTF_HOST)
  307                         isbroadcast = (rte->rt_flags & RTF_BROADCAST);
  308                 else
  309                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
  310         }
  311         /*
  312          * Calculate MTU.  If we have a route that is up, use that,
  313          * otherwise use the interface's MTU.
  314          */
  315         if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) {
  316                 /*
  317                  * This case can happen if the user changed the MTU
  318                  * of an interface after enabling IP on it.  Because
  319                  * most netifs don't keep track of routes pointing to
  320                  * them, there is no way for one to update all its
  321                  * routes when the MTU is changed.
  322                  */
  323                 if (rte->rt_rmx.rmx_mtu > ifp->if_mtu)
  324                         rte->rt_rmx.rmx_mtu = ifp->if_mtu;
  325                 mtu = rte->rt_rmx.rmx_mtu;
  326         } else {
  327                 mtu = ifp->if_mtu;
  328         }
  329         if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
  330                 m->m_flags |= M_MCAST;
  331                 /*
  332                  * IP destination address is multicast.  Make sure "dst"
  333                  * still points to the address in "ro".  (It may have been
  334                  * changed to point to a gateway address, above.)
  335                  */
  336                 dst = (struct sockaddr_in *)&ro->ro_dst;
  337                 /*
  338                  * See if the caller provided any multicast options
  339                  */
  340                 if (imo != NULL) {
  341                         ip->ip_ttl = imo->imo_multicast_ttl;
  342                         if (imo->imo_multicast_vif != -1)
  343                                 ip->ip_src.s_addr =
  344                                     ip_mcast_src ?
  345                                     ip_mcast_src(imo->imo_multicast_vif) :
  346                                     INADDR_ANY;
  347                 } else
  348                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
  349                 /*
  350                  * Confirm that the outgoing interface supports multicast.
  351                  */
  352                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
  353                         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
  354                                 IPSTAT_INC(ips_noroute);
  355                                 error = ENETUNREACH;
  356                                 goto bad;
  357                         }
  358                 }
  359                 /*
  360                  * If source address not specified yet, use address
  361                  * of outgoing interface.
  362                  */
  363                 if (ip->ip_src.s_addr == INADDR_ANY) {
  364                         /* Interface may have no addresses. */
  365                         if (ia != NULL)
  366                                 ip->ip_src = IA_SIN(ia)->sin_addr;
  367                 }
  368 
  369                 if ((imo == NULL && in_mcast_loop) ||
  370                     (imo && imo->imo_multicast_loop)) {
  371                         /*
  372                          * Loop back multicast datagram if not expressly
  373                          * forbidden to do so, even if we are not a member
  374                          * of the group; ip_input() will filter it later,
  375                          * thus deferring a hash lookup and mutex acquisition
  376                          * at the expense of a cheap copy using m_copym().
  377                          */
  378                         ip_mloopback(ifp, m, dst, hlen);
  379                 } else {
  380                         /*
  381                          * If we are acting as a multicast router, perform
  382                          * multicast forwarding as if the packet had just
  383                          * arrived on the interface to which we are about
  384                          * to send.  The multicast forwarding function
  385                          * recursively calls this function, using the
  386                          * IP_FORWARDING flag to prevent infinite recursion.
  387                          *
  388                          * Multicasts that are looped back by ip_mloopback(),
  389                          * above, will be forwarded by the ip_input() routine,
  390                          * if necessary.
  391                          */
  392                         if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) {
  393                                 /*
  394                                  * If rsvp daemon is not running, do not
  395                                  * set ip_moptions. This ensures that the packet
  396                                  * is multicast and not just sent down one link
  397                                  * as prescribed by rsvpd.
  398                                  */
  399                                 if (!V_rsvp_on)
  400                                         imo = NULL;
  401                                 if (ip_mforward &&
  402                                     ip_mforward(ip, ifp, m, imo) != 0) {
  403                                         m_freem(m);
  404                                         goto done;
  405                                 }
  406                         }
  407                 }
  408 
  409                 /*
  410                  * Multicasts with a time-to-live of zero may be looped-
  411                  * back, above, but must not be transmitted on a network.
  412                  * Also, multicasts addressed to the loopback interface
  413                  * are not sent -- the above call to ip_mloopback() will
  414                  * loop back a copy. ip_input() will drop the copy if
  415                  * this host does not belong to the destination group on
  416                  * the loopback interface.
  417                  */
  418                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
  419                         m_freem(m);
  420                         goto done;
  421                 }
  422 
  423                 goto sendit;
  424         }
  425 
  426         /*
  427          * If the source address is not specified yet, use the address
  428          * of the outoing interface.
  429          */
  430         if (ip->ip_src.s_addr == INADDR_ANY) {
  431                 /* Interface may have no addresses. */
  432                 if (ia != NULL) {
  433                         ip->ip_src = IA_SIN(ia)->sin_addr;
  434                 }
  435         }
  436 
  437         /*
  438          * Verify that we have any chance at all of being able to queue the
  439          * packet or packet fragments, unless ALTQ is enabled on the given
  440          * interface in which case packetdrop should be done by queueing.
  441          */
  442 #ifdef ALTQ
  443         if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) &&
  444             ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >=
  445             ifp->if_snd.ifq_maxlen))
  446 #else
  447         if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >=
  448             ifp->if_snd.ifq_maxlen)
  449 #endif /* ALTQ */
  450         {
  451                 error = ENOBUFS;
  452                 IPSTAT_INC(ips_odropped);
  453                 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1);
  454                 goto bad;
  455         }
  456 
  457         /*
  458          * Look for broadcast address and
  459          * verify user is allowed to send
  460          * such a packet.
  461          */
  462         if (isbroadcast) {
  463                 if ((ifp->if_flags & IFF_BROADCAST) == 0) {
  464                         error = EADDRNOTAVAIL;
  465                         goto bad;
  466                 }
  467                 if ((flags & IP_ALLOWBROADCAST) == 0) {
  468                         error = EACCES;
  469                         goto bad;
  470                 }
  471                 /* don't allow broadcast messages to be fragmented */
  472                 if (ip->ip_len > mtu) {
  473                         error = EMSGSIZE;
  474                         goto bad;
  475                 }
  476                 m->m_flags |= M_BCAST;
  477         } else {
  478                 m->m_flags &= ~M_BCAST;
  479         }
  480 
  481 sendit:
  482 #ifdef IPSEC
  483         switch(ip_ipsec_output(&m, inp, &flags, &error, &ifp)) {
  484         case 1:
  485                 goto bad;
  486         case -1:
  487                 goto done;
  488         case 0:
  489         default:
  490                 break;  /* Continue with packet processing. */
  491         }
  492         /*
  493          * Check if there was a route for this packet; return error if not.
  494          */
  495         if (no_route_but_check_spd) {
  496                 IPSTAT_INC(ips_noroute);
  497                 error = EHOSTUNREACH;
  498                 goto bad;
  499         }
  500         /* Update variables that are affected by ipsec4_output(). */
  501         ip = mtod(m, struct ip *);
  502         hlen = ip->ip_hl << 2;
  503 #endif /* IPSEC */
  504 
  505         /* Jump over all PFIL processing if hooks are not active. */
  506         if (!PFIL_HOOKED(&V_inet_pfil_hook))
  507                 goto passout;
  508 
  509         /* Run through list of hooks for output packets. */
  510         odst.s_addr = ip->ip_dst.s_addr;
  511         error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp);
  512         if (error != 0 || m == NULL)
  513                 goto done;
  514 
  515         ip = mtod(m, struct ip *);
  516 
  517         /* See if destination IP address was changed by packet filter. */
  518         if (odst.s_addr != ip->ip_dst.s_addr) {
  519                 m->m_flags |= M_SKIP_FIREWALL;
  520                 /* If destination is now ourself drop to ip_input(). */
  521                 if (in_localip(ip->ip_dst)) {
  522                         m->m_flags |= M_FASTFWD_OURS;
  523                         if (m->m_pkthdr.rcvif == NULL)
  524                                 m->m_pkthdr.rcvif = V_loif;
  525                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  526                                 m->m_pkthdr.csum_flags |=
  527                                     CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
  528                                 m->m_pkthdr.csum_data = 0xffff;
  529                         }
  530                         m->m_pkthdr.csum_flags |=
  531                             CSUM_IP_CHECKED | CSUM_IP_VALID;
  532 #ifdef SCTP
  533                         if (m->m_pkthdr.csum_flags & CSUM_SCTP)
  534                                 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
  535 #endif
  536                         error = netisr_queue(NETISR_IP, m);
  537                         goto done;
  538                 } else
  539                         goto again;     /* Redo the routing table lookup. */
  540         }
  541 
  542 #ifdef IPFIREWALL_FORWARD
  543         /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */
  544         if (m->m_flags & M_FASTFWD_OURS) {
  545                 if (m->m_pkthdr.rcvif == NULL)
  546                         m->m_pkthdr.rcvif = V_loif;
  547                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  548                         m->m_pkthdr.csum_flags |=
  549                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
  550                         m->m_pkthdr.csum_data = 0xffff;
  551                 }
  552 #ifdef SCTP
  553                 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
  554                         m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
  555 #endif
  556                 m->m_pkthdr.csum_flags |=
  557                             CSUM_IP_CHECKED | CSUM_IP_VALID;
  558 
  559                 error = netisr_queue(NETISR_IP, m);
  560                 goto done;
  561         }
  562         /* Or forward to some other address? */
  563         fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
  564         if (fwd_tag) {
  565                 dst = (struct sockaddr_in *)&ro->ro_dst;
  566                 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in));
  567                 m->m_flags |= M_SKIP_FIREWALL;
  568                 m_tag_delete(m, fwd_tag);
  569                 goto again;
  570         }
  571 #endif /* IPFIREWALL_FORWARD */
  572 
  573 passout:
  574         /* 127/8 must not appear on wire - RFC1122. */
  575         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
  576             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
  577                 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
  578                         IPSTAT_INC(ips_badaddr);
  579                         error = EADDRNOTAVAIL;
  580                         goto bad;
  581                 }
  582         }
  583 
  584         m->m_pkthdr.csum_flags |= CSUM_IP;
  585         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
  586         if (sw_csum & CSUM_DELAY_DATA) {
  587                 in_delayed_cksum(m);
  588                 sw_csum &= ~CSUM_DELAY_DATA;
  589         }
  590 #ifdef SCTP
  591         if (sw_csum & CSUM_SCTP) {
  592                 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
  593                 sw_csum &= ~CSUM_SCTP;
  594         }
  595 #endif
  596         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
  597 
  598         /*
  599          * If small enough for interface, or the interface will take
  600          * care of the fragmentation for us, we can just send directly.
  601          */
  602         if (ip->ip_len <= mtu ||
  603             (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 ||
  604             ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) {
  605                 ip->ip_len = htons(ip->ip_len);
  606                 ip->ip_off = htons(ip->ip_off);
  607                 ip->ip_sum = 0;
  608                 if (sw_csum & CSUM_DELAY_IP)
  609                         ip->ip_sum = in_cksum(m, hlen);
  610 
  611                 /*
  612                  * Record statistics for this interface address.
  613                  * With CSUM_TSO the byte/packet count will be slightly
  614                  * incorrect because we count the IP+TCP headers only
  615                  * once instead of for every generated packet.
  616                  */
  617                 if (!(flags & IP_FORWARDING) && ia) {
  618                         if (m->m_pkthdr.csum_flags & CSUM_TSO)
  619                                 ia->ia_ifa.if_opackets +=
  620                                     m->m_pkthdr.len / m->m_pkthdr.tso_segsz;
  621                         else
  622                                 ia->ia_ifa.if_opackets++;
  623                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
  624                 }
  625 #ifdef MBUF_STRESS_TEST
  626                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size)
  627                         m = m_fragment(m, M_DONTWAIT, mbuf_frag_size);
  628 #endif
  629                 /*
  630                  * Reset layer specific mbuf flags
  631                  * to avoid confusing lower layers.
  632                  */
  633                 m->m_flags &= ~(M_PROTOFLAGS);
  634                 error = (*ifp->if_output)(ifp, m,
  635                                 (struct sockaddr *)dst, ro);
  636                 goto done;
  637         }
  638 
  639         /* Balk when DF bit is set or the interface didn't support TSO. */
  640         if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) {
  641                 error = EMSGSIZE;
  642                 IPSTAT_INC(ips_cantfrag);
  643                 goto bad;
  644         }
  645 
  646         /*
  647          * Too large for interface; fragment if possible. If successful,
  648          * on return, m will point to a list of packets to be sent.
  649          */
  650         error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum);
  651         if (error)
  652                 goto bad;
  653         for (; m; m = m0) {
  654                 m0 = m->m_nextpkt;
  655                 m->m_nextpkt = 0;
  656                 if (error == 0) {
  657                         /* Record statistics for this interface address. */
  658                         if (ia != NULL) {
  659                                 ia->ia_ifa.if_opackets++;
  660                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
  661                         }
  662                         /*
  663                          * Reset layer specific mbuf flags
  664                          * to avoid confusing upper layers.
  665                          */
  666                         m->m_flags &= ~(M_PROTOFLAGS);
  667 
  668                         error = (*ifp->if_output)(ifp, m,
  669                             (struct sockaddr *)dst, ro);
  670                 } else
  671                         m_freem(m);
  672         }
  673 
  674         if (error == 0)
  675                 IPSTAT_INC(ips_fragmented);
  676 
  677 done:
  678         if (ro == &iproute && ro->ro_rt && !nortfree) {
  679                 RTFREE(ro->ro_rt);
  680         }
  681         if (ia != NULL)
  682                 ifa_free(&ia->ia_ifa);
  683         return (error);
  684 bad:
  685         m_freem(m);
  686         goto done;
  687 }
  688 
  689 /*
  690  * Create a chain of fragments which fit the given mtu. m_frag points to the
  691  * mbuf to be fragmented; on return it points to the chain with the fragments.
  692  * Return 0 if no error. If error, m_frag may contain a partially built
  693  * chain of fragments that should be freed by the caller.
  694  *
  695  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
  696  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
  697  */
  698 int
  699 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
  700     u_long if_hwassist_flags, int sw_csum)
  701 {
  702         int error = 0;
  703         int hlen = ip->ip_hl << 2;
  704         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
  705         int off;
  706         struct mbuf *m0 = *m_frag;      /* the original packet          */
  707         int firstlen;
  708         struct mbuf **mnext;
  709         int nfrags;
  710 
  711         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
  712                 IPSTAT_INC(ips_cantfrag);
  713                 return EMSGSIZE;
  714         }
  715 
  716         /*
  717          * Must be able to put at least 8 bytes per fragment.
  718          */
  719         if (len < 8)
  720                 return EMSGSIZE;
  721 
  722         /*
  723          * If the interface will not calculate checksums on
  724          * fragmented packets, then do it here.
  725          */
  726         if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
  727             (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
  728                 in_delayed_cksum(m0);
  729                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  730         }
  731 #ifdef SCTP
  732         if (m0->m_pkthdr.csum_flags & CSUM_SCTP &&
  733             (if_hwassist_flags & CSUM_IP_FRAGS) == 0) {
  734                 sctp_delayed_cksum(m0, hlen);
  735                 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP;
  736         }
  737 #endif
  738         if (len > PAGE_SIZE) {
  739                 /* 
  740                  * Fragment large datagrams such that each segment 
  741                  * contains a multiple of PAGE_SIZE amount of data, 
  742                  * plus headers. This enables a receiver to perform 
  743                  * page-flipping zero-copy optimizations.
  744                  *
  745                  * XXX When does this help given that sender and receiver
  746                  * could have different page sizes, and also mtu could
  747                  * be less than the receiver's page size ?
  748                  */
  749                 int newlen;
  750                 struct mbuf *m;
  751 
  752                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
  753                         off += m->m_len;
  754 
  755                 /*
  756                  * firstlen (off - hlen) must be aligned on an 
  757                  * 8-byte boundary
  758                  */
  759                 if (off < hlen)
  760                         goto smart_frag_failure;
  761                 off = ((off - hlen) & ~7) + hlen;
  762                 newlen = (~PAGE_MASK) & mtu;
  763                 if ((newlen + sizeof (struct ip)) > mtu) {
  764                         /* we failed, go back the default */
  765 smart_frag_failure:
  766                         newlen = len;
  767                         off = hlen + len;
  768                 }
  769                 len = newlen;
  770 
  771         } else {
  772                 off = hlen + len;
  773         }
  774 
  775         firstlen = off - hlen;
  776         mnext = &m0->m_nextpkt;         /* pointer to next packet */
  777 
  778         /*
  779          * Loop through length of segment after first fragment,
  780          * make new header and copy data of each part and link onto chain.
  781          * Here, m0 is the original packet, m is the fragment being created.
  782          * The fragments are linked off the m_nextpkt of the original
  783          * packet, which after processing serves as the first fragment.
  784          */
  785         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
  786                 struct ip *mhip;        /* ip header on the fragment */
  787                 struct mbuf *m;
  788                 int mhlen = sizeof (struct ip);
  789 
  790                 MGETHDR(m, M_DONTWAIT, MT_DATA);
  791                 if (m == NULL) {
  792                         error = ENOBUFS;
  793                         IPSTAT_INC(ips_odropped);
  794                         goto done;
  795                 }
  796                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
  797                 /*
  798                  * In the first mbuf, leave room for the link header, then
  799                  * copy the original IP header including options. The payload
  800                  * goes into an additional mbuf chain returned by m_copym().
  801                  */
  802                 m->m_data += max_linkhdr;
  803                 mhip = mtod(m, struct ip *);
  804                 *mhip = *ip;
  805                 if (hlen > sizeof (struct ip)) {
  806                         mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
  807                         mhip->ip_v = IPVERSION;
  808                         mhip->ip_hl = mhlen >> 2;
  809                 }
  810                 m->m_len = mhlen;
  811                 /* XXX do we need to add ip->ip_off below ? */
  812                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
  813                 if (off + len >= ip->ip_len) {  /* last fragment */
  814                         len = ip->ip_len - off;
  815                         m->m_flags |= M_LASTFRAG;
  816                 } else
  817                         mhip->ip_off |= IP_MF;
  818                 mhip->ip_len = htons((u_short)(len + mhlen));
  819                 m->m_next = m_copym(m0, off, len, M_DONTWAIT);
  820                 if (m->m_next == NULL) {        /* copy failed */
  821                         m_free(m);
  822                         error = ENOBUFS;        /* ??? */
  823                         IPSTAT_INC(ips_odropped);
  824                         goto done;
  825                 }
  826                 m->m_pkthdr.len = mhlen + len;
  827                 m->m_pkthdr.rcvif = NULL;
  828 #ifdef MAC
  829                 mac_netinet_fragment(m0, m);
  830 #endif
  831                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
  832                 mhip->ip_off = htons(mhip->ip_off);
  833                 mhip->ip_sum = 0;
  834                 if (sw_csum & CSUM_DELAY_IP)
  835                         mhip->ip_sum = in_cksum(m, mhlen);
  836                 *mnext = m;
  837                 mnext = &m->m_nextpkt;
  838         }
  839         IPSTAT_ADD(ips_ofragments, nfrags);
  840 
  841         /* set first marker for fragment chain */
  842         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
  843         m0->m_pkthdr.csum_data = nfrags;
  844 
  845         /*
  846          * Update first fragment by trimming what's been copied out
  847          * and updating header.
  848          */
  849         m_adj(m0, hlen + firstlen - ip->ip_len);
  850         m0->m_pkthdr.len = hlen + firstlen;
  851         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
  852         ip->ip_off |= IP_MF;
  853         ip->ip_off = htons(ip->ip_off);
  854         ip->ip_sum = 0;
  855         if (sw_csum & CSUM_DELAY_IP)
  856                 ip->ip_sum = in_cksum(m0, hlen);
  857 
  858 done:
  859         *m_frag = m0;
  860         return error;
  861 }
  862 
  863 void
  864 in_delayed_cksum(struct mbuf *m)
  865 {
  866         struct ip *ip;
  867         u_short csum, offset;
  868 
  869         ip = mtod(m, struct ip *);
  870         offset = ip->ip_hl << 2 ;
  871         csum = in_cksum_skip(m, ip->ip_len, offset);
  872         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
  873                 csum = 0xffff;
  874         offset += m->m_pkthdr.csum_data;        /* checksum offset */
  875 
  876         if (offset + sizeof(u_short) > m->m_len) {
  877                 printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
  878                     m->m_len, offset, ip->ip_p);
  879                 /*
  880                  * XXX
  881                  * this shouldn't happen, but if it does, the
  882                  * correct behavior may be to insert the checksum
  883                  * in the appropriate next mbuf in the chain.
  884                  */
  885                 return;
  886         }
  887         *(u_short *)(m->m_data + offset) = csum;
  888 }
  889 
  890 /*
  891  * IP socket option processing.
  892  */
  893 int
  894 ip_ctloutput(struct socket *so, struct sockopt *sopt)
  895 {
  896         struct  inpcb *inp = sotoinpcb(so);
  897         int     error, optval;
  898 
  899         error = optval = 0;
  900         if (sopt->sopt_level != IPPROTO_IP) {
  901                 if ((sopt->sopt_level == SOL_SOCKET) &&
  902                     (sopt->sopt_name == SO_SETFIB)) {
  903                         inp->inp_inc.inc_fibnum = so->so_fibnum;
  904                         return (0);
  905                 }
  906                 return (EINVAL);
  907         }
  908 
  909         switch (sopt->sopt_dir) {
  910         case SOPT_SET:
  911                 switch (sopt->sopt_name) {
  912                 case IP_OPTIONS:
  913 #ifdef notyet
  914                 case IP_RETOPTS:
  915 #endif
  916                 {
  917                         struct mbuf *m;
  918                         if (sopt->sopt_valsize > MLEN) {
  919                                 error = EMSGSIZE;
  920                                 break;
  921                         }
  922                         MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, MT_DATA);
  923                         if (m == NULL) {
  924                                 error = ENOBUFS;
  925                                 break;
  926                         }
  927                         m->m_len = sopt->sopt_valsize;
  928                         error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
  929                                             m->m_len);
  930                         if (error) {
  931                                 m_free(m);
  932                                 break;
  933                         }
  934                         INP_WLOCK(inp);
  935                         error = ip_pcbopts(inp, sopt->sopt_name, m);
  936                         INP_WUNLOCK(inp);
  937                         return (error);
  938                 }
  939 
  940                 case IP_BINDANY:
  941                         if (sopt->sopt_td != NULL) {
  942                                 error = priv_check(sopt->sopt_td,
  943                                     PRIV_NETINET_BINDANY);
  944                                 if (error)
  945                                         break;
  946                         }
  947                         /* FALLTHROUGH */
  948                 case IP_TOS:
  949                 case IP_TTL:
  950                 case IP_MINTTL:
  951                 case IP_RECVOPTS:
  952                 case IP_RECVRETOPTS:
  953                 case IP_RECVDSTADDR:
  954                 case IP_RECVTTL:
  955                 case IP_RECVIF:
  956                 case IP_FAITH:
  957                 case IP_ONESBCAST:
  958                 case IP_DONTFRAG:
  959                         error = sooptcopyin(sopt, &optval, sizeof optval,
  960                                             sizeof optval);
  961                         if (error)
  962                                 break;
  963 
  964                         switch (sopt->sopt_name) {
  965                         case IP_TOS:
  966                                 inp->inp_ip_tos = optval;
  967                                 break;
  968 
  969                         case IP_TTL:
  970                                 inp->inp_ip_ttl = optval;
  971                                 break;
  972 
  973                         case IP_MINTTL:
  974                                 if (optval >= 0 && optval <= MAXTTL)
  975                                         inp->inp_ip_minttl = optval;
  976                                 else
  977                                         error = EINVAL;
  978                                 break;
  979 
  980 #define OPTSET(bit) do {                                                \
  981         INP_WLOCK(inp);                                                 \
  982         if (optval)                                                     \
  983                 inp->inp_flags |= bit;                                  \
  984         else                                                            \
  985                 inp->inp_flags &= ~bit;                                 \
  986         INP_WUNLOCK(inp);                                               \
  987 } while (0)
  988 
  989                         case IP_RECVOPTS:
  990                                 OPTSET(INP_RECVOPTS);
  991                                 break;
  992 
  993                         case IP_RECVRETOPTS:
  994                                 OPTSET(INP_RECVRETOPTS);
  995                                 break;
  996 
  997                         case IP_RECVDSTADDR:
  998                                 OPTSET(INP_RECVDSTADDR);
  999                                 break;
 1000 
 1001                         case IP_RECVTTL:
 1002                                 OPTSET(INP_RECVTTL);
 1003                                 break;
 1004 
 1005                         case IP_RECVIF:
 1006                                 OPTSET(INP_RECVIF);
 1007                                 break;
 1008 
 1009                         case IP_FAITH:
 1010                                 OPTSET(INP_FAITH);
 1011                                 break;
 1012 
 1013                         case IP_ONESBCAST:
 1014                                 OPTSET(INP_ONESBCAST);
 1015                                 break;
 1016                         case IP_DONTFRAG:
 1017                                 OPTSET(INP_DONTFRAG);
 1018                                 break;
 1019                         case IP_BINDANY:
 1020                                 OPTSET(INP_BINDANY);
 1021                                 break;
 1022                         }
 1023                         break;
 1024 #undef OPTSET
 1025 
 1026                 /*
 1027                  * Multicast socket options are processed by the in_mcast
 1028                  * module.
 1029                  */
 1030                 case IP_MULTICAST_IF:
 1031                 case IP_MULTICAST_VIF:
 1032                 case IP_MULTICAST_TTL:
 1033                 case IP_MULTICAST_LOOP:
 1034                 case IP_ADD_MEMBERSHIP:
 1035                 case IP_DROP_MEMBERSHIP:
 1036                 case IP_ADD_SOURCE_MEMBERSHIP:
 1037                 case IP_DROP_SOURCE_MEMBERSHIP:
 1038                 case IP_BLOCK_SOURCE:
 1039                 case IP_UNBLOCK_SOURCE:
 1040                 case IP_MSFILTER:
 1041                 case MCAST_JOIN_GROUP:
 1042                 case MCAST_LEAVE_GROUP:
 1043                 case MCAST_JOIN_SOURCE_GROUP:
 1044                 case MCAST_LEAVE_SOURCE_GROUP:
 1045                 case MCAST_BLOCK_SOURCE:
 1046                 case MCAST_UNBLOCK_SOURCE:
 1047                         error = inp_setmoptions(inp, sopt);
 1048                         break;
 1049 
 1050                 case IP_PORTRANGE:
 1051                         error = sooptcopyin(sopt, &optval, sizeof optval,
 1052                                             sizeof optval);
 1053                         if (error)
 1054                                 break;
 1055 
 1056                         INP_WLOCK(inp);
 1057                         switch (optval) {
 1058                         case IP_PORTRANGE_DEFAULT:
 1059                                 inp->inp_flags &= ~(INP_LOWPORT);
 1060                                 inp->inp_flags &= ~(INP_HIGHPORT);
 1061                                 break;
 1062 
 1063                         case IP_PORTRANGE_HIGH:
 1064                                 inp->inp_flags &= ~(INP_LOWPORT);
 1065                                 inp->inp_flags |= INP_HIGHPORT;
 1066                                 break;
 1067 
 1068                         case IP_PORTRANGE_LOW:
 1069                                 inp->inp_flags &= ~(INP_HIGHPORT);
 1070                                 inp->inp_flags |= INP_LOWPORT;
 1071                                 break;
 1072 
 1073                         default:
 1074                                 error = EINVAL;
 1075                                 break;
 1076                         }
 1077                         INP_WUNLOCK(inp);
 1078                         break;
 1079 
 1080 #ifdef IPSEC
 1081                 case IP_IPSEC_POLICY:
 1082                 {
 1083                         caddr_t req;
 1084                         struct mbuf *m;
 1085 
 1086                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
 1087                                 break;
 1088                         if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
 1089                                 break;
 1090                         req = mtod(m, caddr_t);
 1091                         error = ipsec_set_policy(inp, sopt->sopt_name, req,
 1092                             m->m_len, (sopt->sopt_td != NULL) ?
 1093                             sopt->sopt_td->td_ucred : NULL);
 1094                         m_freem(m);
 1095                         break;
 1096                 }
 1097 #endif /* IPSEC */
 1098 
 1099                 default:
 1100                         error = ENOPROTOOPT;
 1101                         break;
 1102                 }
 1103                 break;
 1104 
 1105         case SOPT_GET:
 1106                 switch (sopt->sopt_name) {
 1107                 case IP_OPTIONS:
 1108                 case IP_RETOPTS:
 1109                         if (inp->inp_options)
 1110                                 error = sooptcopyout(sopt, 
 1111                                                      mtod(inp->inp_options,
 1112                                                           char *),
 1113                                                      inp->inp_options->m_len);
 1114                         else
 1115                                 sopt->sopt_valsize = 0;
 1116                         break;
 1117 
 1118                 case IP_TOS:
 1119                 case IP_TTL:
 1120                 case IP_MINTTL:
 1121                 case IP_RECVOPTS:
 1122                 case IP_RECVRETOPTS:
 1123                 case IP_RECVDSTADDR:
 1124                 case IP_RECVTTL:
 1125                 case IP_RECVIF:
 1126                 case IP_PORTRANGE:
 1127                 case IP_FAITH:
 1128                 case IP_ONESBCAST:
 1129                 case IP_DONTFRAG:
 1130                 case IP_BINDANY:
 1131                         switch (sopt->sopt_name) {
 1132 
 1133                         case IP_TOS:
 1134                                 optval = inp->inp_ip_tos;
 1135                                 break;
 1136 
 1137                         case IP_TTL:
 1138                                 optval = inp->inp_ip_ttl;
 1139                                 break;
 1140 
 1141                         case IP_MINTTL:
 1142                                 optval = inp->inp_ip_minttl;
 1143                                 break;
 1144 
 1145 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
 1146 
 1147                         case IP_RECVOPTS:
 1148                                 optval = OPTBIT(INP_RECVOPTS);
 1149                                 break;
 1150 
 1151                         case IP_RECVRETOPTS:
 1152                                 optval = OPTBIT(INP_RECVRETOPTS);
 1153                                 break;
 1154 
 1155                         case IP_RECVDSTADDR:
 1156                                 optval = OPTBIT(INP_RECVDSTADDR);
 1157                                 break;
 1158 
 1159                         case IP_RECVTTL:
 1160                                 optval = OPTBIT(INP_RECVTTL);
 1161                                 break;
 1162 
 1163                         case IP_RECVIF:
 1164                                 optval = OPTBIT(INP_RECVIF);
 1165                                 break;
 1166 
 1167                         case IP_PORTRANGE:
 1168                                 if (inp->inp_flags & INP_HIGHPORT)
 1169                                         optval = IP_PORTRANGE_HIGH;
 1170                                 else if (inp->inp_flags & INP_LOWPORT)
 1171                                         optval = IP_PORTRANGE_LOW;
 1172                                 else
 1173                                         optval = 0;
 1174                                 break;
 1175 
 1176                         case IP_FAITH:
 1177                                 optval = OPTBIT(INP_FAITH);
 1178                                 break;
 1179 
 1180                         case IP_ONESBCAST:
 1181                                 optval = OPTBIT(INP_ONESBCAST);
 1182                                 break;
 1183                         case IP_DONTFRAG:
 1184                                 optval = OPTBIT(INP_DONTFRAG);
 1185                                 break;
 1186                         case IP_BINDANY:
 1187                                 optval = OPTBIT(INP_BINDANY);
 1188                                 break;
 1189                         }
 1190                         error = sooptcopyout(sopt, &optval, sizeof optval);
 1191                         break;
 1192 
 1193                 /*
 1194                  * Multicast socket options are processed by the in_mcast
 1195                  * module.
 1196                  */
 1197                 case IP_MULTICAST_IF:
 1198                 case IP_MULTICAST_VIF:
 1199                 case IP_MULTICAST_TTL:
 1200                 case IP_MULTICAST_LOOP:
 1201                 case IP_MSFILTER:
 1202                         error = inp_getmoptions(inp, sopt);
 1203                         break;
 1204 
 1205 #ifdef IPSEC
 1206                 case IP_IPSEC_POLICY:
 1207                 {
 1208                         struct mbuf *m = NULL;
 1209                         caddr_t req = NULL;
 1210                         size_t len = 0;
 1211 
 1212                         if (m != 0) {
 1213                                 req = mtod(m, caddr_t);
 1214                                 len = m->m_len;
 1215                         }
 1216                         error = ipsec_get_policy(sotoinpcb(so), req, len, &m);
 1217                         if (error == 0)
 1218                                 error = soopt_mcopyout(sopt, m); /* XXX */
 1219                         if (error == 0)
 1220                                 m_freem(m);
 1221                         break;
 1222                 }
 1223 #endif /* IPSEC */
 1224 
 1225                 default:
 1226                         error = ENOPROTOOPT;
 1227                         break;
 1228                 }
 1229                 break;
 1230         }
 1231         return (error);
 1232 }
 1233 
 1234 /*
 1235  * Routine called from ip_output() to loop back a copy of an IP multicast
 1236  * packet to the input queue of a specified interface.  Note that this
 1237  * calls the output routine of the loopback "driver", but with an interface
 1238  * pointer that might NOT be a loopback interface -- evil, but easier than
 1239  * replicating that code here.
 1240  */
 1241 static void
 1242 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
 1243     int hlen)
 1244 {
 1245         register struct ip *ip;
 1246         struct mbuf *copym;
 1247 
 1248         /*
 1249          * Make a deep copy of the packet because we're going to
 1250          * modify the pack in order to generate checksums.
 1251          */
 1252         copym = m_dup(m, M_DONTWAIT);
 1253         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
 1254                 copym = m_pullup(copym, hlen);
 1255         if (copym != NULL) {
 1256                 /* If needed, compute the checksum and mark it as valid. */
 1257                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 1258                         in_delayed_cksum(copym);
 1259                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
 1260                         copym->m_pkthdr.csum_flags |=
 1261                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 1262                         copym->m_pkthdr.csum_data = 0xffff;
 1263                 }
 1264                 /*
 1265                  * We don't bother to fragment if the IP length is greater
 1266                  * than the interface's MTU.  Can this possibly matter?
 1267                  */
 1268                 ip = mtod(copym, struct ip *);
 1269                 ip->ip_len = htons(ip->ip_len);
 1270                 ip->ip_off = htons(ip->ip_off);
 1271                 ip->ip_sum = 0;
 1272                 ip->ip_sum = in_cksum(copym, hlen);
 1273 #if 1 /* XXX */
 1274                 if (dst->sin_family != AF_INET) {
 1275                         printf("ip_mloopback: bad address family %d\n",
 1276                                                 dst->sin_family);
 1277                         dst->sin_family = AF_INET;
 1278                 }
 1279 #endif
 1280                 if_simloop(ifp, copym, dst->sin_family, 0);
 1281         }
 1282 }

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