FreeBSD/Linux Kernel Cross Reference
sys/net/if_loop.c

     /*      $OpenBSD: if_loop.c,v 1.93 2022/10/21 14:20:03 kn Exp $ */
     /*      $NetBSD: if_loop.c,v 1.15 1996/05/07 02:40:33 thorpej Exp $     */
     
     /*
      * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
     */
    
    /*
     * Copyright (c) 1982, 1986, 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. 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.
     *
     *      @(#)if_loop.c   8.1 (Berkeley) 6/10/93
     */
    
    /*
     *      @(#)COPYRIGHT   1.1 (NRL) 17 January 1995
     *
     * NRL grants permission for redistribution and use in source and binary
     * forms, with or without modification, of the software and documentation
     * created at NRL 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 acknowledgements:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     *      This product includes software developed at the Information
     *      Technology Division, US Naval Research Laboratory.
     * 4. Neither the name of the NRL nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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.
     *
     * The views and conclusions contained in the software and documentation
     * are those of the authors and should not be interpreted as representing
    * official policies, either expressed or implied, of the US Naval
    * Research Laboratory (NRL).
    */
   
   /*
    * Loopback interface driver for protocol testing and timing.
    */
   
   #include "bpfilter.h"
   
   #include <sys/param.h>
   #include <sys/systm.h>
   #include <sys/kernel.h>
   #include <sys/mbuf.h>
   #include <sys/socket.h>
   #include <sys/errno.h>
   #include <sys/ioctl.h>
   #include <sys/time.h>
   
   
   #include <net/if.h>
   #include <net/if_var.h>
   #include <net/if_types.h>
   #include <net/netisr.h>
   #include <net/rtable.h>
   #include <net/route.h>
   
   #include <netinet/in.h>
   
   #ifdef INET6
   #include <netinet/ip6.h>
   #endif
   
   #ifdef MPLS
   #include <netmpls/mpls.h>
   #endif
   
   #if NBPFILTER > 0
   #include <net/bpf.h>
   #endif
   
   #define LOMTU   32768
   
   int     loioctl(struct ifnet *, u_long, caddr_t);
   void    loopattach(int);
   void    lortrequest(struct ifnet *, int, struct rtentry *);
   void    loinput(struct ifnet *, struct mbuf *);
   int     looutput(struct ifnet *,
               struct mbuf *, struct sockaddr *, struct rtentry *);
   
   int     loop_clone_create(struct if_clone *, int);
   int     loop_clone_destroy(struct ifnet *);
   
   struct if_clone loop_cloner =
       IF_CLONE_INITIALIZER("lo", loop_clone_create, loop_clone_destroy);
   
   void
   loopattach(int n)
   {
           if (loop_clone_create(&loop_cloner, 0))
                   panic("unable to create lo0");
   
           if_clone_attach(&loop_cloner);
   }
   
   int
   loop_clone_create(struct if_clone *ifc, int unit)
   {
           struct ifnet *ifp;
   
           ifp = malloc(sizeof(*ifp), M_DEVBUF, M_WAITOK|M_ZERO);
           snprintf(ifp->if_xname, sizeof ifp->if_xname, "lo%d", unit);
           ifp->if_softc = NULL;
           ifp->if_mtu = LOMTU;
           ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
           ifp->if_xflags = IFXF_CLONED;
           ifp->if_rtrequest = lortrequest;
           ifp->if_ioctl = loioctl;
           ifp->if_input = loinput;
           ifp->if_output = looutput;
           ifp->if_type = IFT_LOOP;
           ifp->if_hdrlen = sizeof(u_int32_t);
           if (unit == 0) {
                   if_attachhead(ifp);
                   if_addgroup(ifp, ifc->ifc_name);
                   rtable_l2set(0, 0, ifp->if_index);
           } else
                   if_attach(ifp);
           if_alloc_sadl(ifp);
   #if NBPFILTER > 0
           bpfattach(&ifp->if_bpf, ifp, DLT_LOOP, sizeof(u_int32_t));
   #endif
           return (0);
   }
   
   int
   loop_clone_destroy(struct ifnet *ifp)
   {
           struct ifnet    *p;
           unsigned int     rdomain = 0;
   
           if (ifp->if_index == rtable_loindex(ifp->if_rdomain)) {
                   /* rdomain 0 always needs a loopback */
                   if (ifp->if_rdomain == 0)
                           return (EPERM);
   
                   /* if there is any other interface in this rdomain, deny */
                   NET_LOCK_SHARED();
                   TAILQ_FOREACH(p, &ifnetlist, if_list) {
                           if (p->if_rdomain != ifp->if_rdomain)
                                   continue;
                           if (p->if_index == ifp->if_index)
                                   continue;
                           NET_UNLOCK_SHARED();
                           return (EBUSY);
                   }
                   NET_UNLOCK_SHARED();
   
                   rdomain = ifp->if_rdomain;
           }
   
           if_detach(ifp);
   
           free(ifp, M_DEVBUF, sizeof(*ifp));
   
           if (rdomain)
                   rtable_l2set(rdomain, 0, 0);
           return (0);
   }
   
   void
   loinput(struct ifnet *ifp, struct mbuf *m)
   {
           int error;
   
           if ((m->m_flags & M_PKTHDR) == 0)
                   panic("%s: no header mbuf", __func__);
   
           error = if_input_local(ifp, m, m->m_pkthdr.ph_family);
           if (error)
                   ifp->if_ierrors++;
   }
   
   int
   looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
       struct rtentry *rt)
   {
           if ((m->m_flags & M_PKTHDR) == 0)
                   panic("%s: no header mbuf", __func__);
   
           if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
                   m_freem(m);
                   return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
                           rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
           }
   
           /*
            * Do not call if_input_local() directly.  Queue the packet to avoid
            * stack overflow and make TCP handshake over loopback work.
            */
           return (if_output_local(ifp, m, dst->sa_family));
   }
   
   void
   lortrequest(struct ifnet *ifp, int cmd, struct rtentry *rt)
   {
           if (rt && rt->rt_mtu == 0)
                   rt->rt_mtu = LOMTU;
   }
   
   /*
    * Process an ioctl request.
    */
   int
   loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
   {
           struct ifreq *ifr;
           int error = 0;
   
           switch (cmd) {
           case SIOCSIFFLAGS:
                   break;
   
           case SIOCSIFADDR:
                   ifp->if_flags |= IFF_RUNNING;
                   if_up(ifp);             /* send up RTM_IFINFO */
                   /*
                    * Everything else is done at a higher level.
                    */
                   break;
   
           case SIOCADDMULTI:
           case SIOCDELMULTI:
                   break;
   
           case SIOCSIFMTU:
                   ifr = (struct ifreq *)data;
                   ifp->if_mtu = ifr->ifr_mtu;
                   break;
   
           default:
                   error = ENOTTY;
           }
           return (error);
   }

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