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  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      @(#)if_loop.c   8.2 (Berkeley) 1/9/95
   30  * $FreeBSD: releng/9.1/sys/net/if_loop.c 238876 2012-07-28 23:11:09Z bz $
   31  */
   32 
   33 /*
   34  * Loopback interface driver for protocol testing and timing.
   35  */
   36 
   37 #include "opt_atalk.h"
   38 #include "opt_inet.h"
   39 #include "opt_inet6.h"
   40 #include "opt_ipx.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/kernel.h>
   45 #include <sys/mbuf.h>
   46 #include <sys/module.h>
   47 #include <machine/bus.h>
   48 #include <sys/rman.h>
   49 #include <sys/socket.h>
   50 #include <sys/sockio.h>
   51 #include <sys/sysctl.h>
   52 
   53 #include <net/if.h>
   54 #include <net/if_clone.h>
   55 #include <net/if_types.h>
   56 #include <net/netisr.h>
   57 #include <net/route.h>
   58 #include <net/bpf.h>
   59 #include <net/vnet.h>
   60 
   61 #ifdef  INET
   62 #include <netinet/in.h>
   63 #include <netinet/in_var.h>
   64 #endif
   65 
   66 #ifdef IPX
   67 #include <netipx/ipx.h>
   68 #include <netipx/ipx_if.h>
   69 #endif
   70 
   71 #ifdef INET6
   72 #ifndef INET
   73 #include <netinet/in.h>
   74 #endif
   75 #include <netinet6/in6_var.h>
   76 #include <netinet/ip6.h>
   77 #endif
   78 
   79 #ifdef NETATALK
   80 #include <netatalk/at.h>
   81 #include <netatalk/at_var.h>
   82 #endif
   83 
   84 #include <security/mac/mac_framework.h>
   85 
   86 #ifdef TINY_LOMTU
   87 #define LOMTU   (1024+512)
   88 #elif defined(LARGE_LOMTU)
   89 #define LOMTU   131072
   90 #else
   91 #define LOMTU   16384
   92 #endif
   93 
   94 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
   95 #define LO_CSUM_FEATURES6       (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
   96 #define LO_CSUM_SET             (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
   97                                     CSUM_PSEUDO_HDR | \
   98                                     CSUM_IP_CHECKED | CSUM_IP_VALID | \
   99                                     CSUM_SCTP_VALID)
  100 
  101 int             loioctl(struct ifnet *, u_long, caddr_t);
  102 static void     lortrequest(int, struct rtentry *, struct rt_addrinfo *);
  103 int             looutput(struct ifnet *ifp, struct mbuf *m,
  104                     struct sockaddr *dst, struct route *ro);
  105 static int      lo_clone_create(struct if_clone *, int, caddr_t);
  106 static void     lo_clone_destroy(struct ifnet *);
  107 
  108 VNET_DEFINE(struct ifnet *, loif);      /* Used externally */
  109 
  110 #ifdef VIMAGE
  111 static VNET_DEFINE(struct ifc_simple_data, lo_cloner_data);
  112 static VNET_DEFINE(struct if_clone, lo_cloner);
  113 #define V_lo_cloner_data        VNET(lo_cloner_data)
  114 #define V_lo_cloner             VNET(lo_cloner)
  115 #endif
  116 
  117 IFC_SIMPLE_DECLARE(lo, 1);
  118 
  119 static void
  120 lo_clone_destroy(struct ifnet *ifp)
  121 {
  122 
  123 #ifndef VIMAGE
  124         /* XXX: destroying lo0 will lead to panics. */
  125         KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
  126 #endif
  127 
  128         bpfdetach(ifp);
  129         if_detach(ifp);
  130         if_free(ifp);
  131 }
  132 
  133 static int
  134 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  135 {
  136         struct ifnet *ifp;
  137 
  138         ifp = if_alloc(IFT_LOOP);
  139         if (ifp == NULL)
  140                 return (ENOSPC);
  141 
  142         if_initname(ifp, ifc->ifc_name, unit);
  143         ifp->if_mtu = LOMTU;
  144         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
  145         ifp->if_ioctl = loioctl;
  146         ifp->if_output = looutput;
  147         ifp->if_snd.ifq_maxlen = ifqmaxlen;
  148         ifp->if_capabilities = ifp->if_capenable =
  149             IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
  150         ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
  151         if_attach(ifp);
  152         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
  153         if (V_loif == NULL)
  154                 V_loif = ifp;
  155 
  156         return (0);
  157 }
  158 
  159 static void
  160 vnet_loif_init(const void *unused __unused)
  161 {
  162 
  163 #ifdef VIMAGE
  164         V_lo_cloner = lo_cloner;
  165         V_lo_cloner_data = lo_cloner_data;
  166         V_lo_cloner.ifc_data = &V_lo_cloner_data;
  167         if_clone_attach(&V_lo_cloner);
  168 #else
  169         if_clone_attach(&lo_cloner);
  170 #endif
  171 }
  172 VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  173     vnet_loif_init, NULL);
  174 
  175 #ifdef VIMAGE
  176 static void
  177 vnet_loif_uninit(const void *unused __unused)
  178 {
  179 
  180         if_clone_detach(&V_lo_cloner);
  181         V_loif = NULL;
  182 }
  183 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
  184     vnet_loif_uninit, NULL);
  185 #endif
  186 
  187 static int
  188 loop_modevent(module_t mod, int type, void *data)
  189 {
  190 
  191         switch (type) {
  192         case MOD_LOAD:
  193                 break;
  194 
  195         case MOD_UNLOAD:
  196                 printf("loop module unload - not possible for this module type\n");
  197                 return (EINVAL);
  198 
  199         default:
  200                 return (EOPNOTSUPP);
  201         }
  202         return (0);
  203 }
  204 
  205 static moduledata_t loop_mod = {
  206         "if_lo",
  207         loop_modevent,
  208         0
  209 };
  210 
  211 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  212 
  213 int
  214 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
  215     struct route *ro)
  216 {
  217         u_int32_t af;
  218         struct rtentry *rt = NULL;
  219 #ifdef MAC
  220         int error;
  221 #endif
  222 
  223         M_ASSERTPKTHDR(m); /* check if we have the packet header */
  224 
  225         if (ro != NULL)
  226                 rt = ro->ro_rt;
  227 #ifdef MAC
  228         error = mac_ifnet_check_transmit(ifp, m);
  229         if (error) {
  230                 m_freem(m);
  231                 return (error);
  232         }
  233 #endif
  234 
  235         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
  236                 m_freem(m);
  237                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
  238                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
  239         }
  240 
  241         ifp->if_opackets++;
  242         ifp->if_obytes += m->m_pkthdr.len;
  243 
  244         /* BPF writes need to be handled specially. */
  245         if (dst->sa_family == AF_UNSPEC) {
  246                 bcopy(dst->sa_data, &af, sizeof(af));
  247                 dst->sa_family = af;
  248         }
  249 
  250 #if 1   /* XXX */
  251         switch (dst->sa_family) {
  252         case AF_INET:
  253                 if (ifp->if_capenable & IFCAP_RXCSUM) {
  254                         m->m_pkthdr.csum_data = 0xffff;
  255                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  256                 }
  257                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
  258                 break;
  259         case AF_INET6:
  260 #if 0
  261                 /*
  262                  * XXX-BZ for now always claim the checksum is good despite
  263                  * any interface flags.   This is a workaround for 9.1-R and
  264                  * a proper solution ought to be sought later.
  265                  */
  266                 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
  267                         m->m_pkthdr.csum_data = 0xffff;
  268                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  269                 }
  270 #else
  271                 m->m_pkthdr.csum_data = 0xffff;
  272                 m->m_pkthdr.csum_flags = LO_CSUM_SET;
  273 #endif
  274                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
  275                 break;
  276         case AF_IPX:
  277         case AF_APPLETALK:
  278                 break;
  279         default:
  280                 printf("looutput: af=%d unexpected\n", dst->sa_family);
  281                 m_freem(m);
  282                 return (EAFNOSUPPORT);
  283         }
  284 #endif
  285         return (if_simloop(ifp, m, dst->sa_family, 0));
  286 }
  287 
  288 /*
  289  * if_simloop()
  290  *
  291  * This function is to support software emulation of hardware loopback,
  292  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
  293  * hear their own broadcasts, we create a copy of the packet that we
  294  * would normally receive via a hardware loopback.
  295  *
  296  * This function expects the packet to include the media header of length hlen.
  297  */
  298 int
  299 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
  300 {
  301         int isr;
  302 
  303         M_ASSERTPKTHDR(m);
  304         m_tag_delete_nonpersistent(m);
  305         m->m_pkthdr.rcvif = ifp;
  306 
  307 #ifdef MAC
  308         mac_ifnet_create_mbuf(ifp, m);
  309 #endif
  310 
  311         /*
  312          * Let BPF see incoming packet in the following manner:
  313          *  - Emulated packet loopback for a simplex interface
  314          *    (net/if_ethersubr.c)
  315          *      -> passes it to ifp's BPF
  316          *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
  317          *      -> not passes it to any BPF
  318          *  - Normal packet loopback from myself to myself (net/if_loop.c)
  319          *      -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
  320          */
  321         if (hlen > 0) {
  322                 if (bpf_peers_present(ifp->if_bpf)) {
  323                         bpf_mtap(ifp->if_bpf, m);
  324                 }
  325         } else {
  326                 if (bpf_peers_present(V_loif->if_bpf)) {
  327                         if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
  328                                 /* XXX beware sizeof(af) != 4 */
  329                                 u_int32_t af1 = af;
  330 
  331                                 /*
  332                                  * We need to prepend the address family.
  333                                  */
  334                                 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
  335                         }
  336                 }
  337         }
  338 
  339         /* Strip away media header */
  340         if (hlen > 0) {
  341                 m_adj(m, hlen);
  342 #ifndef __NO_STRICT_ALIGNMENT
  343                 /*
  344                  * Some archs do not like unaligned data, so
  345                  * we move data down in the first mbuf.
  346                  */
  347                 if (mtod(m, vm_offset_t) & 3) {
  348                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
  349                         bcopy(m->m_data,
  350                             (char *)(mtod(m, vm_offset_t)
  351                                 - (mtod(m, vm_offset_t) & 3)),
  352                             m->m_len);
  353                         m->m_data -= (mtod(m,vm_offset_t) & 3);
  354                 }
  355 #endif
  356         }
  357 
  358         /* Deliver to upper layer protocol */
  359         switch (af) {
  360 #ifdef INET
  361         case AF_INET:
  362                 isr = NETISR_IP;
  363                 break;
  364 #endif
  365 #ifdef INET6
  366         case AF_INET6:
  367                 m->m_flags |= M_LOOP;
  368                 isr = NETISR_IPV6;
  369                 break;
  370 #endif
  371 #ifdef IPX
  372         case AF_IPX:
  373                 isr = NETISR_IPX;
  374                 break;
  375 #endif
  376 #ifdef NETATALK
  377         case AF_APPLETALK:
  378                 isr = NETISR_ATALK2;
  379                 break;
  380 #endif
  381         default:
  382                 printf("if_simloop: can't handle af=%d\n", af);
  383                 m_freem(m);
  384                 return (EAFNOSUPPORT);
  385         }
  386         ifp->if_ipackets++;
  387         ifp->if_ibytes += m->m_pkthdr.len;
  388         netisr_queue(isr, m);   /* mbuf is free'd on failure. */
  389         return (0);
  390 }
  391 
  392 /* ARGSUSED */
  393 static void
  394 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
  395 {
  396 
  397         RT_LOCK_ASSERT(rt);
  398         rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
  399 }
  400 
  401 /*
  402  * Process an ioctl request.
  403  */
  404 /* ARGSUSED */
  405 int
  406 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  407 {
  408         struct ifaddr *ifa;
  409         struct ifreq *ifr = (struct ifreq *)data;
  410         int error = 0, mask;
  411 
  412         switch (cmd) {
  413         case SIOCSIFADDR:
  414                 ifp->if_flags |= IFF_UP;
  415                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
  416                 ifa = (struct ifaddr *)data;
  417                 ifa->ifa_rtrequest = lortrequest;
  418                 /*
  419                  * Everything else is done at a higher level.
  420                  */
  421                 break;
  422 
  423         case SIOCADDMULTI:
  424         case SIOCDELMULTI:
  425                 if (ifr == 0) {
  426                         error = EAFNOSUPPORT;           /* XXX */
  427                         break;
  428                 }
  429                 switch (ifr->ifr_addr.sa_family) {
  430 
  431 #ifdef INET
  432                 case AF_INET:
  433                         break;
  434 #endif
  435 #ifdef INET6
  436                 case AF_INET6:
  437                         break;
  438 #endif
  439 
  440                 default:
  441                         error = EAFNOSUPPORT;
  442                         break;
  443                 }
  444                 break;
  445 
  446         case SIOCSIFMTU:
  447                 ifp->if_mtu = ifr->ifr_mtu;
  448                 break;
  449 
  450         case SIOCSIFFLAGS:
  451                 break;
  452 
  453         case SIOCSIFCAP:
  454                 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
  455                 if ((mask & IFCAP_RXCSUM) != 0)
  456                         ifp->if_capenable ^= IFCAP_RXCSUM;
  457                 if ((mask & IFCAP_TXCSUM) != 0)
  458                         ifp->if_capenable ^= IFCAP_TXCSUM;
  459                 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
  460 #if 0
  461                         ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
  462 #else
  463                         error = EOPNOTSUPP;
  464                         break;
  465 #endif
  466                 }
  467                 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
  468 #if 0
  469                         ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
  470 #else
  471                         error = EOPNOTSUPP;
  472                         break;
  473 #endif
  474                 }
  475                 ifp->if_hwassist = 0;
  476                 if (ifp->if_capenable & IFCAP_TXCSUM)
  477                         ifp->if_hwassist = LO_CSUM_FEATURES;
  478 #if 0
  479                 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
  480                         ifp->if_hwassist |= LO_CSUM_FEATURES6;
  481 #endif
  482                 break;
  483 
  484         default:
  485                 error = EINVAL;
  486         }
  487         return (error);
  488 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_loop.c

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