if_loop.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)if_loop.c   8.2 (Berkeley) 1/9/95
   32  * $FreeBSD$
   33  */
   34 
   35 /*
   36  * Loopback interface driver for protocol testing and timing.
   37  */
   38 
   39 #include "opt_inet.h"
   40 #include "opt_inet6.h"
   41 #include "opt_rss.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/kernel.h>
   46 #include <sys/mbuf.h>
   47 #include <sys/module.h>
   48 #include <machine/bus.h>
   49 #include <sys/rman.h>
   50 #include <sys/socket.h>
   51 #include <sys/sockio.h>
   52 #include <sys/sysctl.h>
   53 
   54 #include <net/if.h>
   55 #include <net/if_var.h>
   56 #include <net/if_private.h>
   57 #include <net/if_clone.h>
   58 #include <net/if_types.h>
   59 #include <net/netisr.h>
   60 #include <net/route.h>
   61 #include <net/bpf.h>
   62 #include <net/vnet.h>
   63 
   64 #ifdef  INET
   65 #include <netinet/in.h>
   66 #include <netinet/in_var.h>
   67 #endif
   68 
   69 #ifdef INET6
   70 #ifndef INET
   71 #include <netinet/in.h>
   72 #endif
   73 #include <netinet6/in6_var.h>
   74 #include <netinet/ip6.h>
   75 #endif
   76 
   77 #include <security/mac/mac_framework.h>
   78 
   79 #ifdef TINY_LOMTU
   80 #define LOMTU   (1024+512)
   81 #elif defined(LARGE_LOMTU)
   82 #define LOMTU   131072
   83 #else
   84 #define LOMTU   16384
   85 #endif
   86 
   87 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
   88 #define LO_CSUM_FEATURES6       (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
   89 #define LO_CSUM_SET             (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
   90                                     CSUM_PSEUDO_HDR | \
   91                                     CSUM_IP_CHECKED | CSUM_IP_VALID | \
   92                                     CSUM_SCTP_VALID)
   93 
   94 static int      loioctl(struct ifnet *, u_long, caddr_t);
   95 static int      looutput(struct ifnet *ifp, struct mbuf *m,
   96                     const struct sockaddr *dst, struct route *ro);
   97 
   98 VNET_DEFINE(struct ifnet *, loif);      /* Used externally */
   99 
  100 #ifdef VIMAGE
  101 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
  102 #define V_lo_cloner             VNET(lo_cloner)
  103 #endif
  104 
  105 static struct if_clone *lo_cloner;
  106 static const char loname[] = "lo";
  107 
  108 static int
  109 lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
  110 {
  111         if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
  112                 return (EINVAL);
  113 
  114 #ifndef VIMAGE
  115         /* XXX: destroying lo0 will lead to panics. */
  116         KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
  117 #endif
  118 
  119         bpfdetach(ifp);
  120         if_detach(ifp);
  121         if_free(ifp);
  122 
  123         return (0);
  124 }
  125 
  126 static int
  127 lo_clone_create(struct if_clone *ifc, char *name, size_t len,
  128     struct ifc_data *ifd, struct ifnet **ifpp)
  129 {
  130         struct ifnet *ifp;
  131 
  132         ifp = if_alloc(IFT_LOOP);
  133         if (ifp == NULL)
  134                 return (ENOSPC);
  135 
  136         if_initname(ifp, loname, ifd->unit);
  137         ifp->if_mtu = LOMTU;
  138         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
  139         ifp->if_ioctl = loioctl;
  140         ifp->if_output = looutput;
  141         ifp->if_snd.ifq_maxlen = ifqmaxlen;
  142         ifp->if_capabilities = ifp->if_capenable =
  143             IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
  144         ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
  145         if_attach(ifp);
  146         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
  147         if (V_loif == NULL)
  148                 V_loif = ifp;
  149         *ifpp = ifp;
  150 
  151         return (0);
  152 }
  153 
  154 static void
  155 vnet_loif_init(const void *unused __unused)
  156 {
  157         struct if_clone_addreq req = {
  158                 .create_f = lo_clone_create,
  159                 .destroy_f = lo_clone_destroy,
  160                 .flags = IFC_F_AUTOUNIT,
  161         };
  162         lo_cloner = ifc_attach_cloner(loname, &req);
  163 #ifdef VIMAGE
  164         V_lo_cloner = lo_cloner;
  165 #endif
  166         struct ifc_data ifd = { .unit = 0 };
  167         ifc_create_ifp(loname, &ifd, NULL);
  168 }
  169 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
  170     vnet_loif_init, NULL);
  171 
  172 #ifdef VIMAGE
  173 static void
  174 vnet_loif_uninit(const void *unused __unused)
  175 {
  176 
  177         ifc_detach_cloner(V_lo_cloner);
  178         V_loif = NULL;
  179 }
  180 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
  181     vnet_loif_uninit, NULL);
  182 #endif
  183 
  184 static int
  185 loop_modevent(module_t mod, int type, void *data)
  186 {
  187 
  188         switch (type) {
  189         case MOD_LOAD:
  190                 break;
  191 
  192         case MOD_UNLOAD:
  193                 printf("loop module unload - not possible for this module type\n");
  194                 return (EINVAL);
  195 
  196         default:
  197                 return (EOPNOTSUPP);
  198         }
  199         return (0);
  200 }
  201 
  202 static moduledata_t loop_mod = {
  203         "if_lo",
  204         loop_modevent,
  205         0
  206 };
  207 
  208 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  209 
  210 static int
  211 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
  212     struct route *ro)
  213 {
  214         u_int32_t af;
  215 #ifdef MAC
  216         int error;
  217 #endif
  218 
  219         M_ASSERTPKTHDR(m); /* check if we have the packet header */
  220 
  221 #ifdef MAC
  222         error = mac_ifnet_check_transmit(ifp, m);
  223         if (error) {
  224                 m_freem(m);
  225                 return (error);
  226         }
  227 #endif
  228 
  229         if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
  230                 m_freem(m);
  231                 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
  232         }
  233 
  234         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
  235         if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
  236 
  237 #ifdef RSS
  238         M_HASHTYPE_CLEAR(m);
  239 #endif
  240 
  241         /* BPF writes need to be handled specially. */
  242         if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
  243                 bcopy(dst->sa_data, &af, sizeof(af));
  244         else
  245                 af = RO_GET_FAMILY(ro, dst);
  246 
  247 #if 1   /* XXX */
  248         switch (af) {
  249         case AF_INET:
  250                 if (ifp->if_capenable & IFCAP_RXCSUM) {
  251                         m->m_pkthdr.csum_data = 0xffff;
  252                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  253                 }
  254                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
  255                 break;
  256         case AF_INET6:
  257 #if 0
  258                 /*
  259                  * XXX-BZ for now always claim the checksum is good despite
  260                  * any interface flags.   This is a workaround for 9.1-R and
  261                  * a proper solution ought to be sought later.
  262                  */
  263                 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
  264                         m->m_pkthdr.csum_data = 0xffff;
  265                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  266                 }
  267 #else
  268                 m->m_pkthdr.csum_data = 0xffff;
  269                 m->m_pkthdr.csum_flags = LO_CSUM_SET;
  270 #endif
  271                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
  272                 break;
  273         default:
  274                 printf("looutput: af=%d unexpected\n", af);
  275                 m_freem(m);
  276                 return (EAFNOSUPPORT);
  277         }
  278 #endif
  279         return (if_simloop(ifp, m, af, 0));
  280 }
  281 
  282 /*
  283  * if_simloop()
  284  *
  285  * This function is to support software emulation of hardware loopback,
  286  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
  287  * hear their own broadcasts, we create a copy of the packet that we
  288  * would normally receive via a hardware loopback.
  289  *
  290  * This function expects the packet to include the media header of length hlen.
  291  */
  292 int
  293 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
  294 {
  295         int isr;
  296 
  297         M_ASSERTPKTHDR(m);
  298         m_tag_delete_nonpersistent(m);
  299         m->m_pkthdr.rcvif = ifp;
  300 
  301 #ifdef MAC
  302         mac_ifnet_create_mbuf(ifp, m);
  303 #endif
  304 
  305         /*
  306          * Let BPF see incoming packet in the following manner:
  307          *  - Emulated packet loopback for a simplex interface
  308          *    (net/if_ethersubr.c)
  309          *      -> passes it to ifp's BPF
  310          *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
  311          *      -> not passes it to any BPF
  312          *  - Normal packet loopback from myself to myself (net/if_loop.c)
  313          *      -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
  314          */
  315         if (hlen > 0) {
  316                 if (bpf_peers_present(ifp->if_bpf)) {
  317                         bpf_mtap(ifp->if_bpf, m);
  318                 }
  319         } else {
  320                 if (bpf_peers_present(V_loif->if_bpf)) {
  321                         if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
  322                                 /* XXX beware sizeof(af) != 4 */
  323                                 u_int32_t af1 = af;
  324 
  325                                 /*
  326                                  * We need to prepend the address family.
  327                                  */
  328                                 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
  329                         }
  330                 }
  331         }
  332 
  333         /* Strip away media header */
  334         if (hlen > 0) {
  335                 m_adj(m, hlen);
  336 #ifndef __NO_STRICT_ALIGNMENT
  337                 /*
  338                  * Some archs do not like unaligned data, so
  339                  * we move data down in the first mbuf.
  340                  */
  341                 if (mtod(m, vm_offset_t) & 3) {
  342                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
  343                         bcopy(m->m_data,
  344                             (char *)(mtod(m, vm_offset_t)
  345                                 - (mtod(m, vm_offset_t) & 3)),
  346                             m->m_len);
  347                         m->m_data -= (mtod(m,vm_offset_t) & 3);
  348                 }
  349 #endif
  350         }
  351 
  352         /* Deliver to upper layer protocol */
  353         switch (af) {
  354 #ifdef INET
  355         case AF_INET:
  356                 isr = NETISR_IP;
  357                 break;
  358 #endif
  359 #ifdef INET6
  360         case AF_INET6:
  361                 m->m_flags |= M_LOOP;
  362                 isr = NETISR_IPV6;
  363                 break;
  364 #endif
  365         default:
  366                 printf("if_simloop: can't handle af=%d\n", af);
  367                 m_freem(m);
  368                 return (EAFNOSUPPORT);
  369         }
  370         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
  371         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
  372         netisr_queue(isr, m);   /* mbuf is free'd on failure. */
  373         return (0);
  374 }
  375 
  376 /*
  377  * Process an ioctl request.
  378  */
  379 static int
  380 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  381 {
  382         struct ifreq *ifr = (struct ifreq *)data;
  383         int error = 0, mask;
  384 
  385         switch (cmd) {
  386         case SIOCSIFADDR:
  387                 ifp->if_flags |= IFF_UP;
  388                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
  389                 if_link_state_change(ifp, LINK_STATE_UP);
  390                 /*
  391                  * Everything else is done at a higher level.
  392                  */
  393                 break;
  394 
  395         case SIOCADDMULTI:
  396         case SIOCDELMULTI:
  397                 if (ifr == NULL) {
  398                         error = EAFNOSUPPORT;           /* XXX */
  399                         break;
  400                 }
  401                 switch (ifr->ifr_addr.sa_family) {
  402 #ifdef INET
  403                 case AF_INET:
  404                         break;
  405 #endif
  406 #ifdef INET6
  407                 case AF_INET6:
  408                         break;
  409 #endif
  410 
  411                 default:
  412                         error = EAFNOSUPPORT;
  413                         break;
  414                 }
  415                 break;
  416 
  417         case SIOCSIFMTU:
  418                 ifp->if_mtu = ifr->ifr_mtu;
  419                 break;
  420 
  421         case SIOCSIFFLAGS:
  422                 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
  423                     LINK_STATE_UP: LINK_STATE_DOWN);
  424                 break;
  425 
  426         case SIOCSIFCAP:
  427                 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
  428                 if ((mask & IFCAP_RXCSUM) != 0)
  429                         ifp->if_capenable ^= IFCAP_RXCSUM;
  430                 if ((mask & IFCAP_TXCSUM) != 0)
  431                         ifp->if_capenable ^= IFCAP_TXCSUM;
  432                 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
  433 #if 0
  434                         ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
  435 #else
  436                         error = EOPNOTSUPP;
  437                         break;
  438 #endif
  439                 }
  440                 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
  441 #if 0
  442                         ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
  443 #else
  444                         error = EOPNOTSUPP;
  445                         break;
  446 #endif
  447                 }
  448                 ifp->if_hwassist = 0;
  449                 if (ifp->if_capenable & IFCAP_TXCSUM)
  450                         ifp->if_hwassist = LO_CSUM_FEATURES;
  451 #if 0
  452                 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
  453                         ifp->if_hwassist |= LO_CSUM_FEATURES6;
  454 #endif
  455                 break;
  456 
  457         default:
  458                 error = EINVAL;
  459         }
  460         return (error);
  461 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_loop.c

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