if_loop.c

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    1 /*
    2  * Copyright (c) 1982, 1986, 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  * 3. All advertising materials mentioning features or use of this software
   14  *    must display the following acknowledgement:
   15  *      This product includes software developed by the University of
   16  *      California, Berkeley and its contributors.
   17  * 4. Neither the name of the University nor the names of its contributors
   18  *    may be used to endorse or promote products derived from this software
   19  *    without specific prior written permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31  * SUCH DAMAGE.
   32  *
   33  *      @(#)if_loop.c   8.2 (Berkeley) 1/9/95
   34  * $FreeBSD: releng/5.1/sys/net/if_loop.c 115360 2003-05-28 02:04:33Z silby $
   35  */
   36 
   37 /*
   38  * Loopback interface driver for protocol testing and timing.
   39  */
   40 
   41 #include "opt_atalk.h"
   42 #include "opt_inet.h"
   43 #include "opt_inet6.h"
   44 #include "opt_ipx.h"
   45 #include "opt_mac.h"
   46 
   47 #include <sys/param.h>
   48 #include <sys/systm.h>
   49 #include <sys/kernel.h>
   50 #include <sys/mac.h>
   51 #include <sys/malloc.h>
   52 #include <sys/mbuf.h>
   53 #include <sys/module.h>
   54 #include <machine/bus.h>
   55 #include <sys/rman.h>
   56 #include <sys/socket.h>
   57 #include <sys/sockio.h>
   58 #include <sys/sysctl.h>
   59 
   60 #include <net/if.h>
   61 #include <net/if_types.h>
   62 #include <net/netisr.h>
   63 #include <net/route.h>
   64 #include <net/bpf.h>
   65 #include <net/bpfdesc.h>
   66 
   67 #ifdef  INET
   68 #include <netinet/in.h>
   69 #include <netinet/in_var.h>
   70 #endif
   71 
   72 #ifdef IPX
   73 #include <netipx/ipx.h>
   74 #include <netipx/ipx_if.h>
   75 #endif
   76 
   77 #ifdef INET6
   78 #ifndef INET
   79 #include <netinet/in.h>
   80 #endif
   81 #include <netinet6/in6_var.h>
   82 #include <netinet/ip6.h>
   83 #endif
   84 
   85 #ifdef NETATALK
   86 #include <netatalk/at.h>
   87 #include <netatalk/at_var.h>
   88 #endif
   89 
   90 #ifdef TINY_LOMTU
   91 #define LOMTU   (1024+512)
   92 #elif defined(LARGE_LOMTU)
   93 #define LOMTU   131072
   94 #else
   95 #define LOMTU   16384
   96 #endif
   97 
   98 #define LONAME  "lo"
   99 
  100 struct lo_softc {
  101         struct  ifnet sc_if;            /* network-visible interface */
  102         LIST_ENTRY(lo_softc) sc_next;
  103 };
  104 
  105 int             loioctl(struct ifnet *, u_long, caddr_t);
  106 static void     lortrequest(int, struct rtentry *, struct rt_addrinfo *);
  107 int             looutput(struct ifnet *ifp, struct mbuf *m,
  108                     struct sockaddr *dst, struct rtentry *rt);
  109 int             lo_clone_create(struct if_clone *, int);
  110 void            lo_clone_destroy(struct ifnet *);
  111 
  112 struct ifnet *loif = NULL;                      /* Used externally */
  113 
  114 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
  115 
  116 static LIST_HEAD(lo_list, lo_softc) lo_list;
  117 
  118 struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
  119     lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
  120 
  121 void
  122 lo_clone_destroy(ifp)
  123         struct ifnet *ifp;
  124 {
  125         struct lo_softc *sc;
  126         
  127         sc = ifp->if_softc;
  128 
  129         /* XXX: destroying lo0 will lead to panics. */
  130         KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
  131 
  132         bpfdetach(ifp);
  133         if_detach(ifp);
  134         LIST_REMOVE(sc, sc_next);
  135         free(sc, M_LO);
  136 }
  137 
  138 int
  139 lo_clone_create(ifc, unit)
  140         struct if_clone *ifc;
  141         int unit;
  142 {
  143         struct lo_softc *sc;
  144 
  145         MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
  146 
  147         sc->sc_if.if_name = LONAME;
  148         sc->sc_if.if_unit = unit;
  149         sc->sc_if.if_mtu = LOMTU;
  150         sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
  151         sc->sc_if.if_ioctl = loioctl;
  152         sc->sc_if.if_output = looutput;
  153         sc->sc_if.if_type = IFT_LOOP;
  154         sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
  155         sc->sc_if.if_softc = sc;
  156         if_attach(&sc->sc_if);
  157         bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
  158         LIST_INSERT_HEAD(&lo_list, sc, sc_next);
  159         if (loif == NULL)
  160                 loif = &sc->sc_if;
  161 
  162         return (0);
  163 }
  164 
  165 static int
  166 loop_modevent(module_t mod, int type, void *data) 
  167 { 
  168         switch (type) { 
  169         case MOD_LOAD: 
  170                 LIST_INIT(&lo_list);
  171                 if_clone_attach(&lo_cloner);
  172                 break; 
  173         case MOD_UNLOAD: 
  174                 printf("loop module unload - not possible for this module type\n"); 
  175                 return EINVAL; 
  176         } 
  177         return 0; 
  178 } 
  179 
  180 static moduledata_t loop_mod = { 
  181         "loop", 
  182         loop_modevent, 
  183         0
  184 }; 
  185 
  186 DECLARE_MODULE(loop, loop_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
  187 
  188 int
  189 looutput(ifp, m, dst, rt)
  190         struct ifnet *ifp;
  191         register struct mbuf *m;
  192         struct sockaddr *dst;
  193         register struct rtentry *rt;
  194 {
  195         struct mbuf *n;
  196 
  197         M_ASSERTPKTHDR(m); /* check if we have the packet header */
  198 
  199         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
  200                 m_freem(m);
  201                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
  202                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
  203         }
  204         /*
  205          * KAME requires that the packet to be contiguous on the
  206          * mbuf.  We need to make that sure.
  207          * this kind of code should be avoided.
  208          *
  209          * XXX: KAME may no longer need contiguous packets.  Once
  210          * that has been verified, the following code _should_ be
  211          * removed.
  212          */
  213 
  214         if (m && m->m_next != NULL) {
  215 
  216                 n = m_defrag(m, M_DONTWAIT);
  217 
  218                 if (n == NULL) {
  219                         m_freem(m);
  220                         return (ENOBUFS);
  221                 } else {
  222                         m = n;
  223                 }
  224         }
  225 
  226         ifp->if_opackets++;
  227         ifp->if_obytes += m->m_pkthdr.len;
  228 #if 1   /* XXX */
  229         switch (dst->sa_family) {
  230         case AF_INET:
  231         case AF_INET6:
  232         case AF_IPX:
  233         case AF_APPLETALK:
  234                 break;
  235         default:
  236                 printf("looutput: af=%d unexpected\n", dst->sa_family);
  237                 m_freem(m);
  238                 return (EAFNOSUPPORT);
  239         }
  240 #endif
  241         return(if_simloop(ifp, m, dst->sa_family, 0));
  242 }
  243 
  244 /*
  245  * if_simloop()
  246  *
  247  * This function is to support software emulation of hardware loopback,
  248  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
  249  * hear their own broadcasts, we create a copy of the packet that we
  250  * would normally receive via a hardware loopback.
  251  *
  252  * This function expects the packet to include the media header of length hlen.
  253  */
  254 
  255 int
  256 if_simloop(ifp, m, af, hlen)
  257         struct ifnet *ifp;
  258         struct mbuf *m;
  259         int af;
  260         int hlen;
  261 {
  262         int isr;
  263 
  264         M_ASSERTPKTHDR(m);
  265         m->m_pkthdr.rcvif = ifp;
  266 
  267         /* BPF write needs to be handled specially */
  268         if (af == AF_UNSPEC) {
  269                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
  270                 af = *(mtod(m, int *));
  271                 m->m_len -= sizeof(int);
  272                 m->m_pkthdr.len -= sizeof(int);
  273                 m->m_data += sizeof(int);
  274         }
  275 
  276         /* Let BPF see incoming packet */
  277         if (ifp->if_bpf) {
  278                 struct mbuf m0, *n = m;
  279 
  280                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
  281                         /*
  282                          * We need to prepend the address family as
  283                          * a four byte field.  Cons up a dummy header
  284                          * to pacify bpf.  This is safe because bpf
  285                          * will only read from the mbuf (i.e., it won't
  286                          * try to free it or keep a pointer a to it).
  287                          */
  288                         m0.m_next = m;
  289                         m0.m_len = 4;
  290                         m0.m_data = (char *)&af;
  291                         n = &m0;
  292                 }
  293                 BPF_MTAP(ifp, n);
  294         }
  295 
  296         /* Strip away media header */
  297         if (hlen > 0) {
  298                 m_adj(m, hlen);
  299 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
  300                 /* The alpha doesn't like unaligned data.
  301                  * We move data down in the first mbuf */
  302                 if (mtod(m, vm_offset_t) & 3) {
  303                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
  304                         bcopy(m->m_data, 
  305                             (char *)(mtod(m, vm_offset_t) 
  306                                 - (mtod(m, vm_offset_t) & 3)),
  307                             m->m_len);
  308                         mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
  309                 }
  310 #endif
  311         }
  312 
  313         /* Deliver to upper layer protocol */
  314         switch (af) {
  315 #ifdef INET
  316         case AF_INET:
  317                 isr = NETISR_IP;
  318                 break;
  319 #endif
  320 #ifdef INET6
  321         case AF_INET6:
  322                 m->m_flags |= M_LOOP;
  323                 isr = NETISR_IPV6;
  324                 break;
  325 #endif
  326 #ifdef IPX
  327         case AF_IPX:
  328                 isr = NETISR_IPX;
  329                 break;
  330 #endif
  331 #ifdef NETATALK
  332         case AF_APPLETALK:
  333                 isr = NETISR_ATALK2;
  334                 break;
  335 #endif
  336         default:
  337                 printf("if_simloop: can't handle af=%d\n", af);
  338                 m_freem(m);
  339                 return (EAFNOSUPPORT);
  340         }
  341         ifp->if_ipackets++;
  342         ifp->if_ibytes += m->m_pkthdr.len;
  343         netisr_dispatch(isr, m);
  344         return (0);
  345 }
  346 
  347 /* ARGSUSED */
  348 static void
  349 lortrequest(cmd, rt, info)
  350         int cmd;
  351         struct rtentry *rt;
  352         struct rt_addrinfo *info;
  353 {
  354         if (rt) {
  355                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
  356                 /*
  357                  * For optimal performance, the send and receive buffers
  358                  * should be at least twice the MTU plus a little more for
  359                  * overhead.
  360                  */
  361                 rt->rt_rmx.rmx_recvpipe =
  362                         rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
  363         }
  364 }
  365 
  366 /*
  367  * Process an ioctl request.
  368  */
  369 /* ARGSUSED */
  370 int
  371 loioctl(ifp, cmd, data)
  372         register struct ifnet *ifp;
  373         u_long cmd;
  374         caddr_t data;
  375 {
  376         register struct ifaddr *ifa;
  377         register struct ifreq *ifr = (struct ifreq *)data;
  378         register int error = 0;
  379 
  380         switch (cmd) {
  381 
  382         case SIOCSIFADDR:
  383                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
  384                 ifa = (struct ifaddr *)data;
  385                 ifa->ifa_rtrequest = lortrequest;
  386                 /*
  387                  * Everything else is done at a higher level.
  388                  */
  389                 break;
  390 
  391         case SIOCADDMULTI:
  392         case SIOCDELMULTI:
  393                 if (ifr == 0) {
  394                         error = EAFNOSUPPORT;           /* XXX */
  395                         break;
  396                 }
  397                 switch (ifr->ifr_addr.sa_family) {
  398 
  399 #ifdef INET
  400                 case AF_INET:
  401                         break;
  402 #endif
  403 #ifdef INET6
  404                 case AF_INET6:
  405                         break;
  406 #endif
  407 
  408                 default:
  409                         error = EAFNOSUPPORT;
  410                         break;
  411                 }
  412                 break;
  413 
  414         case SIOCSIFMTU:
  415                 ifp->if_mtu = ifr->ifr_mtu;
  416                 break;
  417 
  418         case SIOCSIFFLAGS:
  419                 break;
  420 
  421         default:
  422                 error = EINVAL;
  423         }
  424         return (error);
  425 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_loop.c

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sys/net/if_loop.c
