Logo Search packages:      
Sourcecode: ecos version File versions  Download package

ip_output.c

//==========================================================================
//
//      src/sys/netinet/ip_output.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * Copyright (c) 1982, 1986, 1988, 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *    @(#)ip_output.c   8.3 (Berkeley) 1/21/94
 * $FreeBSD: src/sys/netinet/ip_output.c,v 1.99.2.16 2001/07/19 06:37:26 kris Exp $
 */

#define _IP_VHL

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>

#ifdef IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#ifdef IPSEC_DEBUG
#include <netkey/key_debug.h>
#else
#define     KEYDEBUG(lev,arg)
#endif
#endif /*IPSEC*/

#include <netinet/ip_fw.h>

#ifdef DUMMYNET
#include <netinet/ip_dummynet.h>
#endif

#ifdef IPFIREWALL_FORWARD_DEBUG
#define print_ip(a)      printf("%ld.%ld.%ld.%ld",(ntohl(a.s_addr)>>24)&0xFF,\
                                      (ntohl(a.s_addr)>>16)&0xFF,\
                                      (ntohl(a.s_addr)>>8)&0xFF,\
                                      (ntohl(a.s_addr))&0xFF);
#endif

u_short ip_id;

static struct mbuf *ip_insertoptions __P((struct mbuf *, struct mbuf *, int *));
static struct ifnet *ip_multicast_if __P((struct in_addr *, int *));
static void ip_mloopback
      __P((struct ifnet *, struct mbuf *, struct sockaddr_in *, int));
static int  ip_getmoptions
      __P((struct sockopt *, struct ip_moptions *));
static int  ip_pcbopts __P((int, struct mbuf **, struct mbuf *));
static int  ip_setmoptions
      __P((struct sockopt *, struct ip_moptions **));

int   ip_optcopy __P((struct ip *, struct ip *));
extern int (*fr_checkp) __P((struct ip *, int, struct ifnet *, int, struct mbuf **));


extern      struct protosw inetsw[];

/*
 * IP output.  The packet in mbuf chain m contains a skeletal IP
 * header (with len, off, ttl, proto, tos, src, dst).
 * The mbuf chain containing the packet will be freed.
 * The mbuf opt, if present, will not be freed.
 */
int
ip_output(m0, opt, ro, flags, imo)
      struct mbuf *m0;
      struct mbuf *opt;
      struct route *ro;
      int flags;
      struct ip_moptions *imo;
{
      struct ip *ip, *mhip;
      struct ifnet *ifp;
      struct mbuf *m = m0;
      int hlen = sizeof (struct ip);
      int len, off, error = 0;
      struct sockaddr_in *dst;
      struct in_ifaddr *ia = NULL;
      int isbroadcast, sw_csum;
#ifdef IPSEC
      struct route iproute;
      struct socket *so = NULL;
      struct secpolicy *sp = NULL;
#endif
      u_int16_t divert_cookie;            /* firewall cookie */
#ifdef IPFIREWALL_FORWARD
      int fwd_rewrite_src = 0;
#endif
      struct ip_fw_chain *rule = NULL;
  
#ifdef IPDIVERT
      /* Get and reset firewall cookie */
      divert_cookie = ip_divert_cookie;
      ip_divert_cookie = 0;
#else
      divert_cookie = 0;
#endif

#if defined(IPFIREWALL) && defined(DUMMYNET)
        /*  
         * dummynet packet are prepended a vestigial mbuf with
         * m_type = MT_DUMMYNET and m_data pointing to the matching
         * rule.
         */ 
        if (m->m_type == MT_DUMMYNET) {
            /*
             * the packet was already tagged, so part of the
             * processing was already done, and we need to go down.
             * Get parameters from the header.
             */
            rule = (struct ip_fw_chain *)(m->m_data) ;
          opt = NULL ;
          ro = & ( ((struct dn_pkt *)m)->ro ) ;
          imo = NULL ;
          dst = ((struct dn_pkt *)m)->dn_dst ;
          ifp = ((struct dn_pkt *)m)->ifp ;
          flags = ((struct dn_pkt *)m)->flags ;

            m0 = m = m->m_next ;
#ifdef IPSEC
          so = ipsec_getsocket(m);
          (void)ipsec_setsocket(m, NULL);
#endif
            ip = mtod(m, struct ip *);
            hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
            if (ro->ro_rt != NULL)
                ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa;
            goto sendit;
        } else
            rule = NULL ;
#endif
#ifdef IPSEC
      so = ipsec_getsocket(m);
      (void)ipsec_setsocket(m, NULL);
#endif

#ifdef      DIAGNOSTIC
      if ((m->m_flags & M_PKTHDR) == 0)
            panic("ip_output no HDR");
      if (!ro)
            panic("ip_output no route, proto = %d",
                  mtod(m, struct ip *)->ip_p);
#endif
      if (opt) {
            m = ip_insertoptions(m, opt, &len);
            hlen = len;
      }
      ip = mtod(m, struct ip *);
      /*
       * Fill in IP header.
       */
      if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) {
            ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
            ip->ip_off &= IP_DF;
#ifdef RANDOM_IP_ID
            ip->ip_id = ip_randomid();
#else
            ip->ip_id = htons(ip_id++);
#endif
            ipstat.ips_localout++;
      } else {
            hlen = IP_VHL_HL(ip->ip_vhl) << 2;
      }

      dst = (struct sockaddr_in *)&ro->ro_dst;
      /*
       * If there is a cached route,
       * check that it is to the same destination
       * and is still up.  If not, free it and try again.
       */
      if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
         dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
            RTFREE(ro->ro_rt);
            ro->ro_rt = (struct rtentry *)0;
      }
      if (ro->ro_rt == 0) {
            dst->sin_family = AF_INET;
            dst->sin_len = sizeof(*dst);
            dst->sin_addr = ip->ip_dst;
      }
      /*
       * If routing to interface only,
       * short circuit routing lookup.
       */
#define ifatoia(ifa)    ((struct in_ifaddr *)(ifa))
#define sintosa(sin)    ((struct sockaddr *)(sin))
      if (flags & IP_ROUTETOIF) {
            if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == 0 &&
                (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == 0) {
                  ipstat.ips_noroute++;
                  error = ENETUNREACH;
                  goto bad;
            }
            ifp = ia->ia_ifp;
            ip->ip_ttl = 1;
            isbroadcast = in_broadcast(dst->sin_addr, ifp);
      } else {
            /*
             * If this is the case, we probably don't want to allocate
             * a protocol-cloned route since we didn't get one from the
             * ULP.  This lets TCP do its thing, while not burdening
             * forwarding or ICMP with the overhead of cloning a route.
             * Of course, we still want to do any cloning requested by
             * the link layer, as this is probably required in all cases
             * for correct operation (as it is for ARP).
             */
            if (ro->ro_rt == 0)
                  rtalloc_ign(ro, RTF_PRCLONING);
            if (ro->ro_rt == 0) {
                  ipstat.ips_noroute++;
                  error = EHOSTUNREACH;
                  goto bad;
            }
            ia = ifatoia(ro->ro_rt->rt_ifa);
            ifp = ro->ro_rt->rt_ifp;
            ro->ro_rt->rt_use++;
            if (ro->ro_rt->rt_flags & RTF_GATEWAY)
                  dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
            if (ro->ro_rt->rt_flags & RTF_HOST)
                  isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
            else
                  isbroadcast = in_broadcast(dst->sin_addr, ifp);
      }
      if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
            struct in_multi *inm;

            m->m_flags |= M_MCAST;
            /*
             * IP destination address is multicast.  Make sure "dst"
             * still points to the address in "ro".  (It may have been
             * changed to point to a gateway address, above.)
             */
            dst = (struct sockaddr_in *)&ro->ro_dst;
            /*
             * See if the caller provided any multicast options
             */
            if (imo != NULL) {
                  ip->ip_ttl = imo->imo_multicast_ttl;
                  if (imo->imo_multicast_ifp != NULL)
                        ifp = imo->imo_multicast_ifp;
                  if (imo->imo_multicast_vif != -1)
                        ip->ip_src.s_addr =
                            ip_mcast_src(imo->imo_multicast_vif);
            } else
                  ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
            /*
             * Confirm that the outgoing interface supports multicast.
             */
            if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
                  if ((ifp->if_flags & IFF_MULTICAST) == 0) {
                        ipstat.ips_noroute++;
                        error = ENETUNREACH;
                        goto bad;
                  }
            }
            /*
             * If source address not specified yet, use address
             * of outgoing interface.
             */
            if (ip->ip_src.s_addr == INADDR_ANY) {
                  register struct in_ifaddr *ia1;

                  TAILQ_FOREACH(ia1, &in_ifaddrhead, ia_link)
                        if (ia1->ia_ifp == ifp) {
                              ip->ip_src = IA_SIN(ia1)->sin_addr;
                              break;
                        }
            }

            IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm);
            if (inm != NULL &&
               (imo == NULL || imo->imo_multicast_loop)) {
                  /*
                   * If we belong to the destination multicast group
                   * on the outgoing interface, and the caller did not
                   * forbid loopback, loop back a copy.
                   */
                  ip_mloopback(ifp, m, dst, hlen);
            }
            else {
                  /*
                   * If we are acting as a multicast router, perform
                   * multicast forwarding as if the packet had just
                   * arrived on the interface to which we are about
                   * to send.  The multicast forwarding function
                   * recursively calls this function, using the
                   * IP_FORWARDING flag to prevent infinite recursion.
                   *
                   * Multicasts that are looped back by ip_mloopback(),
                   * above, will be forwarded by the ip_input() routine,
                   * if necessary.
                   */
                  if (ip_mrouter && (flags & IP_FORWARDING) == 0) {
                        /*
                         * Check if rsvp daemon is running. If not, don't
                         * set ip_moptions. This ensures that the packet
                         * is multicast and not just sent down one link
                         * as prescribed by rsvpd.
                         */
                        if (!rsvp_on)
                          imo = NULL;
                        if (ip_mforward(ip, ifp, m, imo) != 0) {
                              m_freem(m);
                              goto done;
                        }
                  }
            }

            /*
             * Multicasts with a time-to-live of zero may be looped-
             * back, above, but must not be transmitted on a network.
             * Also, multicasts addressed to the loopback interface
             * are not sent -- the above call to ip_mloopback() will
             * loop back a copy if this host actually belongs to the
             * destination group on the loopback interface.
             */
            if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
                  m_freem(m);
                  goto done;
            }

            goto sendit;
      }
#ifndef notdef
      /*
       * If source address not specified yet, use address
       * of outgoing interface.
       */
      if (ip->ip_src.s_addr == INADDR_ANY) {
            ip->ip_src = IA_SIN(ia)->sin_addr;
#ifdef IPFIREWALL_FORWARD
            /* Keep note that we did this - if the firewall changes
             * the next-hop, our interface may change, changing the
             * default source IP. It's a shame so much effort happens
             * twice. Oh well. 
             */
            fwd_rewrite_src++;
#endif /* IPFIREWALL_FORWARD */
      }
#endif /* notdef */
#ifdef ALTQ
      /*
       * disable packet drop hack.
       * packetdrop should be done by queueing.
       */
#else /* !ALTQ */
      /*
       * Verify that we have any chance at all of being able to queue
       *      the packet or packet fragments
       */
      if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
            ifp->if_snd.ifq_maxlen) {
                  error = ENOBUFS;
                  goto bad;
      }
#endif /* !ALTQ */

      /*
       * Look for broadcast address and
       * and verify user is allowed to send
       * such a packet.
       */
      if (isbroadcast) {
            if ((ifp->if_flags & IFF_BROADCAST) == 0) {
                  error = EADDRNOTAVAIL;
                  goto bad;
            }
            if ((flags & IP_ALLOWBROADCAST) == 0) {
                  error = EACCES;
                  goto bad;
            }
            /* don't allow broadcast messages to be fragmented */
            if ((u_short)ip->ip_len > ifp->if_mtu) {
                  error = EMSGSIZE;
                  goto bad;
            }
            m->m_flags |= M_BCAST;
      } else {
            m->m_flags &= ~M_BCAST;
      }

sendit:
#ifdef IPSEC
      /* get SP for this packet */
      if (so == NULL)
            sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
      else
            sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);

      if (sp == NULL) {
            ipsecstat.out_inval++;
            goto bad;
      }

      error = 0;

      /* check policy */
      switch (sp->policy) {
      case IPSEC_POLICY_DISCARD:
            /*
             * This packet is just discarded.
             */
            ipsecstat.out_polvio++;
            goto bad;

      case IPSEC_POLICY_BYPASS:
      case IPSEC_POLICY_NONE:
            /* no need to do IPsec. */
            goto skip_ipsec;
      
      case IPSEC_POLICY_IPSEC:
            if (sp->req == NULL) {
                  /* acquire a policy */
                  error = key_spdacquire(sp);
                  goto bad;
            }
            break;

      case IPSEC_POLICY_ENTRUST:
      default:
            printf("ip_output: Invalid policy found. %d\n", sp->policy);
      }
    {
      struct ipsec_output_state state;
      bzero(&state, sizeof(state));
      state.m = m;
      if (flags & IP_ROUTETOIF) {
            state.ro = &iproute;
            bzero(&iproute, sizeof(iproute));
      } else
            state.ro = ro;
      state.dst = (struct sockaddr *)dst;

      ip->ip_sum = 0;

      /*
       * XXX
       * delayed checksums are not currently compatible with IPsec
       */
      if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
            in_delayed_cksum(m);
            m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
      }

      HTONS(ip->ip_len);
      HTONS(ip->ip_off);

      error = ipsec4_output(&state, sp, flags);

      m = state.m;
      if (flags & IP_ROUTETOIF) {
            /*
             * if we have tunnel mode SA, we may need to ignore
             * IP_ROUTETOIF.
             */
            if (state.ro != &iproute || state.ro->ro_rt != NULL) {
                  flags &= ~IP_ROUTETOIF;
                  ro = state.ro;
            }
      } else
            ro = state.ro;
      dst = (struct sockaddr_in *)state.dst;
      if (error) {
            /* mbuf is already reclaimed in ipsec4_output. */
            m0 = NULL;
            switch (error) {
            case EHOSTUNREACH:
            case ENETUNREACH:
            case EMSGSIZE:
            case ENOBUFS:
            case ENOMEM:
                  break;
            default:
                  printf("ip4_output (ipsec): error code %d\n", error);
                  /*fall through*/
            case ENOENT:
                  /* don't show these error codes to the user */
                  error = 0;
                  break;
            }
            goto bad;
      }

      /* be sure to update variables that are affected by ipsec4_output() */
      ip = mtod(m, struct ip *);
#ifdef _IP_VHL
      hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
      hlen = ip->ip_hl << 2;
#endif
      if (ro->ro_rt == NULL) {
            if ((flags & IP_ROUTETOIF) == 0) {
                  printf("ip_output: "
                        "can't update route after IPsec processing\n");
                  error = EHOSTUNREACH;   /*XXX*/
                  goto bad;
            }
      } else {
            if (state.encap) {
                  ia = ifatoia(ro->ro_rt->rt_ifa);
                  ifp = ro->ro_rt->rt_ifp;
            }
      }
    }

      /* make it flipped, again. */
      NTOHS(ip->ip_len);
      NTOHS(ip->ip_off);
skip_ipsec:
#endif /*IPSEC*/

      /*
       * IpHack's section.
       * - Xlate: translate packet's addr/port (NAT).
       * - Firewall: deny/allow/etc.
       * - Wrap: fake packet's addr/port <unimpl.>
       * - Encapsulate: put it in another IP and send out. <unimp.>
       */ 
      if (fr_checkp) {
            struct  mbuf    *m1 = m;

            if ((error = (*fr_checkp)(ip, hlen, ifp, 1, &m1)) || !m1)
                  goto done;
            ip = mtod(m = m1, struct ip *);
      }

      /*
       * Check with the firewall...
       */
      if (fw_enable && ip_fw_chk_ptr) {
            struct sockaddr_in *old = dst;

            off = (*ip_fw_chk_ptr)(&ip,
                hlen, ifp, &divert_cookie, &m, &rule, &dst);
                /*
                 * On return we must do the following:
                 * IP_FW_PORT_DENY_FLAG         -> drop the pkt (XXX new)
                 * 1<=off<= 0xffff   -> DIVERT
                 * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
                 * (off & IP_FW_PORT_TEE_FLAG)  -> TEE the packet
                 * dst != old        -> IPFIREWALL_FORWARD
                 * off==0, dst==old  -> accept
                 * If some of the above modules is not compiled in, then
                 * we should't have to check the corresponding condition
                 * (because the ipfw control socket should not accept
                 * unsupported rules), but better play safe and drop
                 * packets in case of doubt.
                 */
            if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
                  if (m)
                        m_freem(m);
                  error = EACCES ;
                  goto done ;
            }
            ip = mtod(m, struct ip *);
            if (off == 0 && dst == old) /* common case */
                  goto pass ;
#ifdef DUMMYNET
                if ((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!
                     */ 
                error = dummynet_io(off & 0xffff, DN_TO_IP_OUT, m,
                        ifp,ro,dst,rule, flags);
                goto done;
            }
#endif   
#ifdef IPDIVERT
            if (off != 0 && (off & IP_FW_PORT_DYNT_FLAG) == 0) {
                  struct mbuf *clone = NULL;

                  /* Clone packet if we're doing a 'tee' */
                  if ((off & IP_FW_PORT_TEE_FLAG) != 0)
                        clone = m_dup(m, M_DONTWAIT);

                  /*
                   * XXX
                   * delayed checksums are not currently compatible
                   * with divert sockets.
                   */
                  if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
                        in_delayed_cksum(m);
                        m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
                  }

                  /* Restore packet header fields to original values */
                  HTONS(ip->ip_len);
                  HTONS(ip->ip_off);

                  /* Deliver packet to divert input routine */
                  ip_divert_cookie = divert_cookie;
                  divert_packet(m, 0, off & 0xffff);

                  /* If 'tee', continue with original packet */
                  if (clone != NULL) {
                        m = clone;
                        ip = mtod(m, struct ip *);
                        goto pass;
                  }
                  goto done;
            }
#endif

#ifdef IPFIREWALL_FORWARD
            /* Here we check dst to make sure it's directly reachable on the
             * interface we previously thought it was.
             * If it isn't (which may be likely in some situations) we have
             * to re-route it (ie, find a route for the next-hop and the
             * associated interface) and set them here. This is nested
             * forwarding which in most cases is undesirable, except where
             * such control is nigh impossible. So we do it here.
             * And I'm babbling.
             */
            if (off == 0 && old != dst) {
                  struct in_ifaddr *ia;

                  /* It's changed... */
                  /* There must be a better way to do this next line... */
                  static struct route sro_fwd, *ro_fwd = &sro_fwd;
#ifdef IPFIREWALL_FORWARD_DEBUG
                  printf("IPFIREWALL_FORWARD: New dst ip: ");
                  print_ip(dst->sin_addr);
                  printf("\n");
#endif
                  /*
                   * We need to figure out if we have been forwarded
                   * to a local socket. If so then we should somehow 
                   * "loop back" to ip_input, and get directed to the
                   * PCB as if we had received this packet. This is
                   * because it may be dificult to identify the packets
                   * you want to forward until they are being output
                   * and have selected an interface. (e.g. locally
                   * initiated packets) If we used the loopback inteface,
                   * we would not be able to control what happens 
                   * as the packet runs through ip_input() as
                   * it is done through a ISR.
                   */
                  TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) {
                        /*
                         * If the addr to forward to is one
                         * of ours, we pretend to
                         * be the destination for this packet.
                         */
                        if (IA_SIN(ia)->sin_addr.s_addr ==
                                     dst->sin_addr.s_addr)
                              break;
                  }
                  if (ia) {
                        /* tell ip_input "dont filter" */
                        ip_fw_fwd_addr = dst;
                        if (m->m_pkthdr.rcvif == NULL)
                              m->m_pkthdr.rcvif = ifunit("lo0");
                        if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
                              m->m_pkthdr.csum_flags |=
                                  CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
                              m0->m_pkthdr.csum_data = 0xffff;
                        }
                        m->m_pkthdr.csum_flags |=
                            CSUM_IP_CHECKED | CSUM_IP_VALID;
                        HTONS(ip->ip_len);
                        HTONS(ip->ip_off);
                        ip_input(m);
                        goto done;
                  }
                  /* Some of the logic for this was
                   * nicked from above.
                   *
                   * This rewrites the cached route in a local PCB.
                   * Is this what we want to do?
                   */
                  bcopy(dst, &ro_fwd->ro_dst, sizeof(*dst));

                  ro_fwd->ro_rt = 0;
                  rtalloc_ign(ro_fwd, RTF_PRCLONING);

                  if (ro_fwd->ro_rt == 0) {
                        ipstat.ips_noroute++;
                        error = EHOSTUNREACH;
                        goto bad;
                  }

                  ia = ifatoia(ro_fwd->ro_rt->rt_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)
                        isbroadcast =
                            (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
                  else
                        isbroadcast = in_broadcast(dst->sin_addr, ifp);
                  RTFREE(ro->ro_rt);
                  ro->ro_rt = ro_fwd->ro_rt;
                  dst = (struct sockaddr_in *)&ro_fwd->ro_dst;

                  /*
                   * 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)->sin_addr;
                  goto pass ;
            }
#endif /* IPFIREWALL_FORWARD */
                /*
                 * if we get here, none of the above matches, and 
                 * we have to drop the pkt
                 */
            m_freem(m);
                error = EACCES; /* not sure this is the right error msg */
                goto done;
      }

pass:
      m->m_pkthdr.csum_flags |= CSUM_IP;
      sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
      if (sw_csum & CSUM_DELAY_DATA) {
            in_delayed_cksum(m);
            sw_csum &= ~CSUM_DELAY_DATA;
      }
      m->m_pkthdr.csum_flags &= ifp->if_hwassist;

      /*
       * 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 ||
          ifp->if_hwassist & CSUM_FRAGMENT) {
            HTONS(ip->ip_len);
            HTONS(ip->ip_off);
            ip->ip_sum = 0;
            if (sw_csum & CSUM_DELAY_IP) {
                  if (ip->ip_vhl == IP_VHL_BORING) {
                        ip->ip_sum = in_cksum_hdr(ip);
                  } else {
                        ip->ip_sum = in_cksum(m, hlen);
                  }
            }

            /* Record statistics for this interface address. */
            if (!(flags & IP_FORWARDING) && ia != NULL) {
                  ia->ia_ifa.if_opackets++;
                  ia->ia_ifa.if_obytes += m->m_pkthdr.len;
            }

#ifdef IPSEC
            /* clean ipsec history once it goes out of the node */
            ipsec_delaux(m);
#endif

            error = (*ifp->if_output)(ifp, m,
                        (struct sockaddr *)dst, ro->ro_rt);
            goto done;
      }
      /*
       * Too large for interface; fragment if possible.
       * Must be able to put at least 8 bytes per fragment.
       */
      if (ip->ip_off & IP_DF) {
            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.
             */
            if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST))
                && !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU)
                && (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
                  ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
            }
            ipstat.ips_cantfrag++;
            goto bad;
      }
      len = (ifp->if_mtu - hlen) &~ 7;
      if (len < 8) {
            error = EMSGSIZE;
            goto bad;
      }

      /*
       * if the interface will not calculate checksums on
       * fragmented packets, then do it here.
       */
      if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA &&
          (ifp->if_hwassist & CSUM_IP_FRAGS) == 0) {
            in_delayed_cksum(m);
            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.
       */
      m0 = m;
      mhlen = sizeof (struct ip);
      for (off = hlen + len; off < (u_short)ip->ip_len; off += len) {
            MGETHDR(m, M_DONTWAIT, MT_HEADER);
            if (m == 0) {
                  error = ENOBUFS;
                  ipstat.ips_odropped++;
                  goto sendorfree;
            }
            m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
            m->m_data += max_linkhdr;
            mhip = mtod(m, struct ip *);
            *mhip = *ip;
            if (hlen > sizeof (struct ip)) {
                  mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
                  mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
            }
            m->m_len = mhlen;
            mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
            if (ip->ip_off & IP_MF)
                  mhip->ip_off |= IP_MF;
            if (off + len >= (u_short)ip->ip_len)
                  len = (u_short)ip->ip_len - off;
            else
                  mhip->ip_off |= IP_MF;
            mhip->ip_len = htons((u_short)(len + mhlen));
            m->m_next = m_copy(m0, off, len);
            if (m->m_next == 0) {
                  (void) m_free(m);
                  error = ENOBUFS;  /* ??? */
                  ipstat.ips_odropped++;
                  goto sendorfree;
            }
            m->m_pkthdr.len = mhlen + len;
            m->m_pkthdr.rcvif = (struct ifnet *)0;
            m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
            HTONS(mhip->ip_off);
            mhip->ip_sum = 0;
            if (sw_csum & CSUM_DELAY_IP) {
                  if (mhip->ip_vhl == IP_VHL_BORING) {
                        mhip->ip_sum = in_cksum_hdr(mhip);
                  } else {
                        mhip->ip_sum = in_cksum(m, mhlen);
                  }
            }
            *mnext = m;
            mnext = &m->m_nextpkt;
            nfrags++;
      }
      ipstat.ips_ofragments += nfrags;

      /* set first/last markers for fragment chain */
      m->m_flags |= M_LASTFRAG;
      m0->m_flags |= M_FIRSTFRAG | M_FRAG;
      m0->m_pkthdr.csum_data = nfrags;

      /*
       * Update first fragment by trimming what's been copied out
       * and updating header, then send each fragment (in order).
       */
      m = m0;
      m_adj(m, hlen + firstlen - (u_short)ip->ip_len);
      m->m_pkthdr.len = hlen + firstlen;
      ip->ip_len = htons((u_short)m->m_pkthdr.len);
      ip->ip_off |= IP_MF;
      HTONS(ip->ip_off);
      ip->ip_sum = 0;
      if (sw_csum & CSUM_DELAY_IP) {
            if (ip->ip_vhl == IP_VHL_BORING) {
                  ip->ip_sum = in_cksum_hdr(ip);
            } else {
                  ip->ip_sum = in_cksum(m, hlen);
            }
      }
sendorfree:
      for (m = m0; m; m = m0) {
            m0 = m->m_nextpkt;
            m->m_nextpkt = 0;
#ifdef IPSEC
            /* clean ipsec history once it goes out of the node */
            ipsec_delaux(m);
#endif
            if (error == 0) {
                  /* Record statistics for this interface address. */
                  if (ia != NULL) {
                        ia->ia_ifa.if_opackets++;
                        ia->ia_ifa.if_obytes += m->m_pkthdr.len;
                  }
                  
                  error = (*ifp->if_output)(ifp, m,
                      (struct sockaddr *)dst, ro->ro_rt);
            } else
                  m_freem(m);
      }

      if (error == 0)
            ipstat.ips_fragmented++;
    }
done:
#ifdef IPSEC
      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:%p\n", sp));
            key_freesp(sp);
      }
#endif /* IPSEC */
      return (error);
bad:
      m_freem(m0);
      goto done;
}

void
in_delayed_cksum(struct mbuf *m)
{
      struct ip *ip;
      u_short csum, offset;

      ip = mtod(m, struct ip *);
      offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
      csum = in_cksum_skip(m, ip->ip_len, offset);
      if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
            csum = 0xffff;
      offset += m->m_pkthdr.csum_data;    /* checksum offset */

      if (offset + sizeof(u_short) > m->m_len) {
            printf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
                m->m_len, offset, ip->ip_p);
            /*
             * XXX
             * this shouldn't happen, but if it does, the
             * correct behavior may be to insert the checksum
             * in the existing chain instead of rearranging it.
             */
            m = m_pullup(m, offset + sizeof(u_short));
      }
      *(u_short *)(m->m_data + offset) = csum;
}

/*
 * Insert IP options into preformed packet.
 * Adjust IP destination as required for IP source routing,
 * as indicated by a non-zero in_addr at the start of the options.
 *
 * XXX This routine assumes that the packet has no options in place.
 */
static struct mbuf *
ip_insertoptions(m, opt, phlen)
      register struct mbuf *m;
      struct mbuf *opt;
      int *phlen;
{
      register struct ipoption *p = mtod(opt, struct ipoption *);
      struct mbuf *n;
      register struct ip *ip = mtod(m, struct ip *);
      unsigned optlen;

      optlen = opt->m_len - sizeof(p->ipopt_dst);
      if (optlen + (u_short)ip->ip_len > IP_MAXPACKET)
            return (m);       /* XXX should fail */
      if (p->ipopt_dst.s_addr)
            ip->ip_dst = p->ipopt_dst;
      if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
            MGETHDR(n, M_DONTWAIT, MT_HEADER);
            if (n == 0)
                  return (m);
            n->m_pkthdr.rcvif = (struct ifnet *)0;
            n->m_pkthdr.len = m->m_pkthdr.len + optlen;
            m->m_len -= sizeof(struct ip);
            m->m_data += sizeof(struct ip);
            n->m_next = m;
            m = n;
            m->m_len = optlen + sizeof(struct ip);
            m->m_data += max_linkhdr;
            (void)memcpy(mtod(m, void *), ip, sizeof(struct ip));
      } else {
            m->m_data -= optlen;
            m->m_len += optlen;
            m->m_pkthdr.len += optlen;
            ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
      }
      ip = mtod(m, struct ip *);
      bcopy(p->ipopt_list, ip + 1, optlen);
      *phlen = sizeof(struct ip) + optlen;
      ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
      ip->ip_len += optlen;
      return (m);
}

/*
 * Copy options from ip to jp,
 * omitting those not copied during fragmentation.
 */
int
ip_optcopy(ip, jp)
      struct ip *ip, *jp;
{
      register u_char *cp, *dp;
      int opt, optlen, cnt;

      cp = (u_char *)(ip + 1);
      dp = (u_char *)(jp + 1);
      cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof (struct ip);
      for (; cnt > 0; cnt -= optlen, cp += optlen) {
            opt = cp[0];
            if (opt == IPOPT_EOL)
                  break;
            if (opt == IPOPT_NOP) {
                  /* Preserve for IP mcast tunnel's LSRR alignment. */
                  *dp++ = IPOPT_NOP;
                  optlen = 1;
                  continue;
            }
#ifdef DIAGNOSTIC
            if (cnt < IPOPT_OLEN + sizeof(*cp))
                  panic("malformed IPv4 option passed to ip_optcopy");
#endif
            optlen = cp[IPOPT_OLEN];
#ifdef DIAGNOSTIC
            if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
                  panic("malformed IPv4 option passed to ip_optcopy");
#endif
            /* bogus lengths should have been caught by ip_dooptions */
            if (optlen > cnt)
                  optlen = cnt;
            if (IPOPT_COPIED(opt)) {
                  bcopy(cp, dp, optlen);
                  dp += optlen;
            }
      }
      for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
            *dp++ = IPOPT_EOL;
      return (optlen);
}

/*
 * IP socket option processing.
 */
int
ip_ctloutput(so, sopt)
      struct socket *so;
      struct sockopt *sopt;
{
      struct      inpcb *inp = sotoinpcb(so);
      int   error, optval;

      error = optval = 0;
      if (sopt->sopt_level != IPPROTO_IP) {
            return (EINVAL);
      }

      switch (sopt->sopt_dir) {
      case SOPT_SET:
            switch (sopt->sopt_name) {
            case IP_OPTIONS:
#ifdef notyet
            case IP_RETOPTS:
#endif
            {
                  struct mbuf *m;
                  if (sopt->sopt_valsize > MLEN) {
                        error = EMSGSIZE;
                        break;
                  }
                  MGET(m, sopt->sopt_p ? M_WAIT : M_DONTWAIT, MT_HEADER);
                  if (m == 0) {
                        error = ENOBUFS;
                        break;
                  }
                  m->m_len = sopt->sopt_valsize;
                  error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
                                  m->m_len);
                  
                  return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
                                 m));
            }

            case IP_TOS:
            case IP_TTL:
            case IP_RECVOPTS:
            case IP_RECVRETOPTS:
            case IP_RECVDSTADDR:
            case IP_RECVIF:
#if defined(NFAITH) && NFAITH > 0
            case IP_FAITH:
#endif
                  error = sooptcopyin(sopt, &optval, sizeof optval,
                                  sizeof optval);
                  if (error)
                        break;

                  switch (sopt->sopt_name) {
                  case IP_TOS:
                        inp->inp_ip_tos = optval;
                        break;

                  case IP_TTL:
                        inp->inp_ip_ttl = optval;
                        break;
#define     OPTSET(bit) \
      if (optval) \
            inp->inp_flags |= bit; \
      else \
            inp->inp_flags &= ~bit;

                  case IP_RECVOPTS:
                        OPTSET(INP_RECVOPTS);
                        break;

                  case IP_RECVRETOPTS:
                        OPTSET(INP_RECVRETOPTS);
                        break;

                  case IP_RECVDSTADDR:
                        OPTSET(INP_RECVDSTADDR);
                        break;

                  case IP_RECVIF:
                        OPTSET(INP_RECVIF);
                        break;

#if defined(NFAITH) && NFAITH > 0
                  case IP_FAITH:
                        OPTSET(INP_FAITH);
                        break;
#endif
                  }
                  break;
#undef OPTSET

            case IP_MULTICAST_IF:
            case IP_MULTICAST_VIF:
            case IP_MULTICAST_TTL:
            case IP_MULTICAST_LOOP:
            case IP_ADD_MEMBERSHIP:
            case IP_DROP_MEMBERSHIP:
                  error = ip_setmoptions(sopt, &inp->inp_moptions);
                  break;

            case IP_PORTRANGE:
                  error = sooptcopyin(sopt, &optval, sizeof optval,
                                  sizeof optval);
                  if (error)
                        break;

                  switch (optval) {
                  case IP_PORTRANGE_DEFAULT:
                        inp->inp_flags &= ~(INP_LOWPORT);
                        inp->inp_flags &= ~(INP_HIGHPORT);
                        break;

                  case IP_PORTRANGE_HIGH:
                        inp->inp_flags &= ~(INP_LOWPORT);
                        inp->inp_flags |= INP_HIGHPORT;
                        break;

                  case IP_PORTRANGE_LOW:
                        inp->inp_flags &= ~(INP_HIGHPORT);
                        inp->inp_flags |= INP_LOWPORT;
                        break;

                  default:
                        error = EINVAL;
                        break;
                  }
                  break;

#ifdef IPSEC
            case IP_IPSEC_POLICY:
            {
                  caddr_t req;
                  size_t len = 0;
                  int priv;
                  struct mbuf *m;
                  int optname;

                  if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
                        break;
                  if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
                        break;
                  priv = (sopt->sopt_p != NULL &&
                        suser(sopt->sopt_p) != 0) ? 0 : 1;
                  req = mtod(m, caddr_t);
                  len = m->m_len;
                  optname = sopt->sopt_name;
                  error = ipsec4_set_policy(inp, optname, req, len, priv);
                  m_freem(m);
                  break;
            }
#endif /*IPSEC*/

            default:
                  error = ENOPROTOOPT;
                  break;
            }
            break;

      case SOPT_GET:
            switch (sopt->sopt_name) {
            case IP_OPTIONS:
            case IP_RETOPTS:
                  if (inp->inp_options)
                        error = sooptcopyout(sopt, 
                                         mtod(inp->inp_options,
                                            char *),
                                         inp->inp_options->m_len);
                  else
                        sopt->sopt_valsize = 0;
                  break;

            case IP_TOS:
            case IP_TTL:
            case IP_RECVOPTS:
            case IP_RECVRETOPTS:
            case IP_RECVDSTADDR:
            case IP_RECVIF:
            case IP_PORTRANGE:
#if defined(NFAITH) && NFAITH > 0
            case IP_FAITH:
#endif
                  switch (sopt->sopt_name) {

                  case IP_TOS:
                        optval = inp->inp_ip_tos;
                        break;

                  case IP_TTL:
                        optval = inp->inp_ip_ttl;
                        break;

#define     OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)

                  case IP_RECVOPTS:
                        optval = OPTBIT(INP_RECVOPTS);
                        break;

                  case IP_RECVRETOPTS:
                        optval = OPTBIT(INP_RECVRETOPTS);
                        break;

                  case IP_RECVDSTADDR:
                        optval = OPTBIT(INP_RECVDSTADDR);
                        break;

                  case IP_RECVIF:
                        optval = OPTBIT(INP_RECVIF);
                        break;

                  case IP_PORTRANGE:
                        if (inp->inp_flags & INP_HIGHPORT)
                              optval = IP_PORTRANGE_HIGH;
                        else if (inp->inp_flags & INP_LOWPORT)
                              optval = IP_PORTRANGE_LOW;
                        else
                              optval = 0;
                        break;

#if defined(NFAITH) && NFAITH > 0
                  case IP_FAITH:
                        optval = OPTBIT(INP_FAITH);
                        break;
#endif
                  }
                  error = sooptcopyout(sopt, &optval, sizeof optval);
                  break;

            case IP_MULTICAST_IF:
            case IP_MULTICAST_VIF:
            case IP_MULTICAST_TTL:
            case IP_MULTICAST_LOOP:
            case IP_ADD_MEMBERSHIP:
            case IP_DROP_MEMBERSHIP:
                  error = ip_getmoptions(sopt, inp->inp_moptions);
                  break;

#ifdef IPSEC
            case IP_IPSEC_POLICY:
            {
                  struct mbuf *m = NULL;
                  caddr_t req = NULL;
                  size_t len = 0;

                  if (m != 0) {
                        req = mtod(m, caddr_t);
                        len = m->m_len;
                  }
                  error = ipsec4_get_policy(sotoinpcb(so), req, len, &m);
                  if (error == 0)
                        error = soopt_mcopyout(sopt, m); /* XXX */
                  if (error == 0)
                        m_freem(m);
                  break;
            }
#endif /*IPSEC*/

            default:
                  error = ENOPROTOOPT;
                  break;
            }
            break;
      }
      return (error);
}

/*
 * Set up IP options in pcb for insertion in output packets.
 * Store in mbuf with pointer in pcbopt, adding pseudo-option
 * with destination address if source routed.
 */
static int
ip_pcbopts(optname, pcbopt, m)
      int optname;
      struct mbuf **pcbopt;
      register struct mbuf *m;
{
      register int cnt, optlen;
      register u_char *cp;
      u_char opt;

      /* turn off any old options */
      if (*pcbopt)
            (void)m_free(*pcbopt);
      *pcbopt = 0;
      if (m == (struct mbuf *)0 || m->m_len == 0) {
            /*
             * Only turning off any previous options.
             */
            if (m)
                  (void)m_free(m);
            return (0);
      }

#ifndef     vax
      if (m->m_len % sizeof(int32_t))
            goto bad;
#endif
      /*
       * IP first-hop destination address will be stored before
       * actual options; move other options back
       * and clear it when none present.
       */
      if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
            goto bad;
      cnt = m->m_len;
      m->m_len += sizeof(struct in_addr);
      cp = mtod(m, u_char *) + sizeof(struct in_addr);
      ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
      bzero(mtod(m, caddr_t), sizeof(struct in_addr));

      for (; cnt > 0; cnt -= optlen, cp += optlen) {
            opt = cp[IPOPT_OPTVAL];
            if (opt == IPOPT_EOL)
                  break;
            if (opt == IPOPT_NOP)
                  optlen = 1;
            else {
                  if (cnt < IPOPT_OLEN + sizeof(*cp))
                        goto bad;
                  optlen = cp[IPOPT_OLEN];
                  if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt)
                        goto bad;
            }
            switch (opt) {

            default:
                  break;

            case IPOPT_LSRR:
            case IPOPT_SSRR:
                  /*
                   * user process specifies route as:
                   *    ->A->B->C->D
                   * D must be our final destination (but we can't
                   * check that since we may not have connected yet).
                   * A is first hop destination, which doesn't appear in
                   * actual IP option, but is stored before the options.
                   */
                  if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
                        goto bad;
                  m->m_len -= sizeof(struct in_addr);
                  cnt -= sizeof(struct in_addr);
                  optlen -= sizeof(struct in_addr);
                  cp[IPOPT_OLEN] = optlen;
                  /*
                   * Move first hop before start of options.
                   */
                  bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
                      sizeof(struct in_addr));
                  /*
                   * Then copy rest of options back
                   * to close up the deleted entry.
                   */
                  ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
                      sizeof(struct in_addr)),
                      (caddr_t)&cp[IPOPT_OFFSET+1],
                      (unsigned)cnt + sizeof(struct in_addr));
                  break;
            }
      }
      if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
            goto bad;
      *pcbopt = m;
      return (0);

bad:
      (void)m_free(m);
      return (EINVAL);
}

/*
 * XXX
 * The whole multicast option thing needs to be re-thought.
 * Several of these options are equally applicable to non-multicast
 * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
 * standard option (IP_TTL).
 */

/*
 * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
 */
static struct ifnet *
ip_multicast_if(a, ifindexp)
      struct in_addr *a;
      int *ifindexp;
{
      int ifindex;
      struct ifnet *ifp;

      if (ifindexp)
            *ifindexp = 0;
      if (ntohl(a->s_addr) >> 24 == 0) {
            ifindex = ntohl(a->s_addr) & 0xffffff;
            if (ifindex < 0 || if_index < ifindex)
                  return NULL;
            ifp = ifindex2ifnet[ifindex];
            if (ifindexp)
                  *ifindexp = ifindex;
      } else {
            INADDR_TO_IFP(*a, ifp);
      }
      return ifp;
}

/*
 * Set the IP multicast options in response to user setsockopt().
 */
static int
ip_setmoptions(sopt, imop)
      struct sockopt *sopt;
      struct ip_moptions **imop;
{
      int error = 0;
      int i;
      struct in_addr addr;
      struct ip_mreq mreq;
      struct ifnet *ifp;
      struct ip_moptions *imo = *imop;
      struct route ro;
      struct sockaddr_in *dst;
      int ifindex;
      int s;

      if (imo == NULL) {
            /*
             * No multicast option buffer attached to the pcb;
             * allocate one and initialize to default values.
             */
            imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS,
                M_WAITOK);

            if (imo == NULL)
                  return (ENOBUFS);
            *imop = imo;
            imo->imo_multicast_ifp = NULL;
            imo->imo_multicast_addr.s_addr = INADDR_ANY;
            imo->imo_multicast_vif = -1;
            imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
            imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
            imo->imo_num_memberships = 0;
      }

      switch (sopt->sopt_name) {
      /* store an index number for the vif you wanna use in the send */
      case IP_MULTICAST_VIF:
            if (legal_vif_num == 0) {
                  error = EOPNOTSUPP;
                  break;
            }
            error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
            if (error)
                  break;
            if (!legal_vif_num(i) && (i != -1)) {
                  error = EINVAL;
                  break;
            }
            imo->imo_multicast_vif = i;
            break;

      case IP_MULTICAST_IF:
            /*
             * Select the interface for outgoing multicast packets.
             */
            error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
            if (error)
                  break;
            /*
             * INADDR_ANY is used to remove a previous selection.
             * When no interface is selected, a default one is
             * chosen every time a multicast packet is sent.
             */
            if (addr.s_addr == INADDR_ANY) {
                  imo->imo_multicast_ifp = NULL;
                  break;
            }
            /*
             * The selected interface is identified by its local
             * IP address.  Find the interface and confirm that
             * it supports multicasting.
             */
            s = splimp();
            ifp = ip_multicast_if(&addr, &ifindex);
            if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
                  splx(s);
                  error = EADDRNOTAVAIL;
                  break;
            }
            imo->imo_multicast_ifp = ifp;
            if (ifindex)
                  imo->imo_multicast_addr = addr;
            else
                  imo->imo_multicast_addr.s_addr = INADDR_ANY;
            splx(s);
            break;

      case IP_MULTICAST_TTL:
            /*
             * Set the IP time-to-live for outgoing multicast packets.
             * The original multicast API required a char argument,
             * which is inconsistent with the rest of the socket API.
             * We allow either a char or an int.
             */
            if (sopt->sopt_valsize == 1) {
                  u_char ttl;
                  error = sooptcopyin(sopt, &ttl, 1, 1);
                  if (error)
                        break;
                  imo->imo_multicast_ttl = ttl;
            } else {
                  u_int ttl;
                  error = sooptcopyin(sopt, &ttl, sizeof ttl, 
                                  sizeof ttl);
                  if (error)
                        break;
                  if (ttl > 255)
                        error = EINVAL;
                  else
                        imo->imo_multicast_ttl = ttl;
            }
            break;

      case IP_MULTICAST_LOOP:
            /*
             * Set the loopback flag for outgoing multicast packets.
             * Must be zero or one.  The original multicast API required a
             * char argument, which is inconsistent with the rest
             * of the socket API.  We allow either a char or an int.
             */
            if (sopt->sopt_valsize == 1) {
                  u_char loop;
                  error = sooptcopyin(sopt, &loop, 1, 1);
                  if (error)
                        break;
                  imo->imo_multicast_loop = !!loop;
            } else {
                  u_int loop;
                  error = sooptcopyin(sopt, &loop, sizeof loop,
                                  sizeof loop);
                  if (error)
                        break;
                  imo->imo_multicast_loop = !!loop;
            }
            break;

      case IP_ADD_MEMBERSHIP:
            /*
             * Add a multicast group membership.
             * Group must be a valid IP multicast address.
             */
            error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
            if (error)
                  break;

            if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
                  error = EINVAL;
                  break;
            }
            s = splimp();
            /*
             * If no interface address was provided, use the interface of
             * the route to the given multicast address.
             */
            if (mreq.imr_interface.s_addr == INADDR_ANY) {
                  bzero((caddr_t)&ro, sizeof(ro));
                  dst = (struct sockaddr_in *)&ro.ro_dst;
                  dst->sin_len = sizeof(*dst);
                  dst->sin_family = AF_INET;
                  dst->sin_addr = mreq.imr_multiaddr;
                  rtalloc(&ro);
                  if (ro.ro_rt == NULL) {
                        error = EADDRNOTAVAIL;
                        splx(s);
                        break;
                  }
                  ifp = ro.ro_rt->rt_ifp;
                  rtfree(ro.ro_rt);
            }
            else {
                  ifp = ip_multicast_if(&mreq.imr_interface, NULL);
            }

            /*
             * See if we found an interface, and confirm that it
             * supports multicast.
             */
            if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
                  error = EADDRNOTAVAIL;
                  splx(s);
                  break;
            }
            /*
             * See if the membership already exists or if all the
             * membership slots are full.
             */
            for (i = 0; i < imo->imo_num_memberships; ++i) {
                  if (imo->imo_membership[i]->inm_ifp == ifp &&
                      imo->imo_membership[i]->inm_addr.s_addr
                                    == mreq.imr_multiaddr.s_addr)
                        break;
            }
            if (i < imo->imo_num_memberships) {
                  error = EADDRINUSE;
                  splx(s);
                  break;
            }
            if (i == IP_MAX_MEMBERSHIPS) {
                  error = ETOOMANYREFS;
                  splx(s);
                  break;
            }
            /*
             * Everything looks good; add a new record to the multicast
             * address list for the given interface.
             */
            if ((imo->imo_membership[i] =
                in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
                  error = ENOBUFS;
                  splx(s);
                  break;
            }
            ++imo->imo_num_memberships;
            splx(s);
            break;

      case IP_DROP_MEMBERSHIP:
            /*
             * Drop a multicast group membership.
             * Group must be a valid IP multicast address.
             */
            error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
            if (error)
                  break;

            if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
                  error = EINVAL;
                  break;
            }

            s = splimp();
            /*
             * If an interface address was specified, get a pointer
             * to its ifnet structure.
             */
            if (mreq.imr_interface.s_addr == INADDR_ANY)
                  ifp = NULL;
            else {
                  ifp = ip_multicast_if(&mreq.imr_interface, NULL);
                  if (ifp == NULL) {
                        error = EADDRNOTAVAIL;
                        splx(s);
                        break;
                  }
            }
            /*
             * Find the membership in the membership array.
             */
            for (i = 0; i < imo->imo_num_memberships; ++i) {
                  if ((ifp == NULL ||
                       imo->imo_membership[i]->inm_ifp == ifp) &&
                       imo->imo_membership[i]->inm_addr.s_addr ==
                       mreq.imr_multiaddr.s_addr)
                        break;
            }
            if (i == imo->imo_num_memberships) {
                  error = EADDRNOTAVAIL;
                  splx(s);
                  break;
            }
            /*
             * Give up the multicast address record to which the
             * membership points.
             */
            in_delmulti(imo->imo_membership[i]);
            /*
             * Remove the gap in the membership array.
             */
            for (++i; i < imo->imo_num_memberships; ++i)
                  imo->imo_membership[i-1] = imo->imo_membership[i];
            --imo->imo_num_memberships;
            splx(s);
            break;

      default:
            error = EOPNOTSUPP;
            break;
      }

      /*
       * If all options have default values, no need to keep the mbuf.
       */
      if (imo->imo_multicast_ifp == NULL &&
          imo->imo_multicast_vif == -1 &&
          imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
          imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
          imo->imo_num_memberships == 0) {
            free(*imop, M_IPMOPTS);
            *imop = NULL;
      }

      return (error);
}

/*
 * Return the IP multicast options in response to user getsockopt().
 */
static int
ip_getmoptions(sopt, imo)
      struct sockopt *sopt;
      register struct ip_moptions *imo;
{
      struct in_addr addr;
      struct in_ifaddr *ia;
      int error, optval;
      u_char coptval;

      error = 0;
      switch (sopt->sopt_name) {
      case IP_MULTICAST_VIF: 
            if (imo != NULL)
                  optval = imo->imo_multicast_vif;
            else
                  optval = -1;
            error = sooptcopyout(sopt, &optval, sizeof optval);
            break;

      case IP_MULTICAST_IF:
            if (imo == NULL || imo->imo_multicast_ifp == NULL)
                  addr.s_addr = INADDR_ANY;
            else if (imo->imo_multicast_addr.s_addr) {
                  /* return the value user has set */
                  addr = imo->imo_multicast_addr;
            } else {
                  IFP_TO_IA(imo->imo_multicast_ifp, ia);
                  addr.s_addr = (ia == NULL) ? INADDR_ANY
                        : IA_SIN(ia)->sin_addr.s_addr;
            }
            error = sooptcopyout(sopt, &addr, sizeof addr);
            break;

      case IP_MULTICAST_TTL:
            if (imo == 0)
                  optval = coptval = IP_DEFAULT_MULTICAST_TTL;
            else
                  optval = coptval = imo->imo_multicast_ttl;
            if (sopt->sopt_valsize == 1)
                  error = sooptcopyout(sopt, &coptval, 1);
            else
                  error = sooptcopyout(sopt, &optval, sizeof optval);
            break;

      case IP_MULTICAST_LOOP:
            if (imo == 0)
                  optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
            else
                  optval = coptval = imo->imo_multicast_loop;
            if (sopt->sopt_valsize == 1)
                  error = sooptcopyout(sopt, &coptval, 1);
            else
                  error = sooptcopyout(sopt, &optval, sizeof optval);
            break;

      default:
            error = ENOPROTOOPT;
            break;
      }
      return (error);
}

/*
 * Discard the IP multicast options.
 */
void
ip_freemoptions(imo)
      register struct ip_moptions *imo;
{
      register int i;

      if (imo != NULL) {
            for (i = 0; i < imo->imo_num_memberships; ++i)
                  in_delmulti(imo->imo_membership[i]);
            free(imo, M_IPMOPTS);
      }
}

/*
 * Routine called from ip_output() to loop back a copy of an IP multicast
 * packet to the input queue of a specified interface.  Note that this
 * calls the output routine of the loopback "driver", but with an interface
 * pointer that might NOT be a loopback interface -- evil, but easier than
 * replicating that code here.
 */
static void
ip_mloopback(ifp, m, dst, hlen)
      struct ifnet *ifp;
      register struct mbuf *m;
      register struct sockaddr_in *dst;
      int hlen;
{
      register struct ip *ip;
      struct mbuf *copym;

      copym = m_copy(m, 0, M_COPYALL);
      if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
            copym = m_pullup(copym, hlen);
      if (copym != NULL) {
            /*
             * We don't bother to fragment if the IP length is greater
             * than the interface's MTU.  Can this possibly matter?
             */
            ip = mtod(copym, struct ip *);
            HTONS(ip->ip_len);
            HTONS(ip->ip_off);
            ip->ip_sum = 0;
            if (ip->ip_vhl == IP_VHL_BORING) {
                  ip->ip_sum = in_cksum_hdr(ip);
            } else {
                  ip->ip_sum = in_cksum(copym, hlen);
            }
            /*
             * NB:
             * It's not clear whether there are any lingering
             * reentrancy problems in other areas which might
             * be exposed by using ip_input directly (in
             * particular, everything which modifies the packet
             * in-place).  Yet another option is using the
             * protosw directly to deliver the looped back
             * packet.  For the moment, we'll err on the side
             * of safety by using if_simloop().
             */
#if 1 /* XXX */
            if (dst->sin_family != AF_INET) {
                  printf("ip_mloopback: bad address family %d\n",
                                    dst->sin_family);
                  dst->sin_family = AF_INET;
            }
#endif

#ifdef notdef
            copym->m_pkthdr.rcvif = ifp;
            ip_input(copym);
#else
            /* if the checksum hasn't been computed, mark it as valid */
            if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
                  copym->m_pkthdr.csum_flags |=
                      CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
                  copym->m_pkthdr.csum_data = 0xffff;
            }
            if_simloop(ifp, copym, dst->sin_family, 0);
#endif
      }
}

Generated by  Doxygen 1.6.0   Back to index