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_clone.h>
   57 #include <net/if_types.h>
   58 #include <net/netisr.h>
   59 #include <net/route.h>
   60 #include <net/bpf.h>
   61 #include <net/vnet.h>
   62 
   63 #ifdef  INET
   64 #include <netinet/in.h>
   65 #include <netinet/in_var.h>
   66 #endif
   67 
   68 #ifdef INET6
   69 #ifndef INET
   70 #include <netinet/in.h>
   71 #endif
   72 #include <netinet6/in6_var.h>
   73 #include <netinet/ip6.h>
   74 #endif
   75 
   76 #include <security/mac/mac_framework.h>
   77 
   78 #ifdef TINY_LOMTU
   79 #define LOMTU   (1024+512)
   80 #elif defined(LARGE_LOMTU)
   81 #define LOMTU   131072
   82 #else
   83 #define LOMTU   16384
   84 #endif
   85 
   86 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
   87 #define LO_CSUM_FEATURES6       (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
   88 #define LO_CSUM_SET             (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
   89                                     CSUM_PSEUDO_HDR | \
   90                                     CSUM_IP_CHECKED | CSUM_IP_VALID | \
   91                                     CSUM_SCTP_VALID)
   92 
   93 int             loioctl(struct ifnet *, u_long, caddr_t);
   94 int             looutput(struct ifnet *ifp, struct mbuf *m,
   95                     const struct sockaddr *dst, struct route *ro);
   96 static int      lo_clone_create(struct if_clone *, int, caddr_t);
   97 static void     lo_clone_destroy(struct ifnet *);
   98 
   99 VNET_DEFINE(struct ifnet *, loif);      /* Used externally */
  100 
  101 #ifdef VIMAGE
  102 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
  103 #define V_lo_cloner             VNET(lo_cloner)
  104 #endif
  105 
  106 static struct if_clone *lo_cloner;
  107 static const char loname[] = "lo";
  108 
  109 static void
  110 lo_clone_destroy(struct ifnet *ifp)
  111 {
  112 
  113 #ifndef VIMAGE
  114         /* XXX: destroying lo0 will lead to panics. */
  115         KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
  116 #endif
  117 
  118         bpfdetach(ifp);
  119         if_detach(ifp);
  120         if_free(ifp);
  121 }
  122 
  123 static int
  124 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  125 {
  126         struct ifnet *ifp;
  127 
  128         ifp = if_alloc(IFT_LOOP);
  129         if (ifp == NULL)
  130                 return (ENOSPC);
  131 
  132         if_initname(ifp, loname, unit);
  133         ifp->if_mtu = LOMTU;
  134         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
  135         ifp->if_ioctl = loioctl;
  136         ifp->if_output = looutput;
  137         ifp->if_snd.ifq_maxlen = ifqmaxlen;
  138         ifp->if_capabilities = ifp->if_capenable =
  139             IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
  140         ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
  141         if_attach(ifp);
  142         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
  143         if (V_loif == NULL)
  144                 V_loif = ifp;
  145 
  146         return (0);
  147 }
  148 
  149 static void
  150 vnet_loif_init(const void *unused __unused)
  151 {
  152 
  153 #ifdef VIMAGE
  154         lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
  155             1);
  156         V_lo_cloner = lo_cloner;
  157 #else
  158         lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
  159             1);
  160 #endif
  161 }
  162 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
  163     vnet_loif_init, NULL);
  164 
  165 #ifdef VIMAGE
  166 static void
  167 vnet_loif_uninit(const void *unused __unused)
  168 {
  169 
  170         if_clone_detach(V_lo_cloner);
  171         V_loif = NULL;
  172 }
  173 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
  174     vnet_loif_uninit, NULL);
  175 #endif
  176 
  177 static int
  178 loop_modevent(module_t mod, int type, void *data)
  179 {
  180 
  181         switch (type) {
  182         case MOD_LOAD:
  183                 break;
  184 
  185         case MOD_UNLOAD:
  186                 printf("loop module unload - not possible for this module type\n");
  187                 return (EINVAL);
  188 
  189         default:
  190                 return (EOPNOTSUPP);
  191         }
  192         return (0);
  193 }
  194 
  195 static moduledata_t loop_mod = {
  196         "if_lo",
  197         loop_modevent,
  198         0
  199 };
  200 
  201 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  202 
  203 int
  204 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
  205     struct route *ro)
  206 {
  207         u_int32_t af;
  208 #ifdef MAC
  209         int error;
  210 #endif
  211 
  212         M_ASSERTPKTHDR(m); /* check if we have the packet header */
  213 
  214 #ifdef MAC
  215         error = mac_ifnet_check_transmit(ifp, m);
  216         if (error) {
  217                 m_freem(m);
  218                 return (error);
  219         }
  220 #endif
  221 
  222         if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
  223                 m_freem(m);
  224                 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
  225         }
  226 
  227         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
  228         if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
  229 
  230 #ifdef RSS
  231         M_HASHTYPE_CLEAR(m);
  232 #endif
  233 
  234         /* BPF writes need to be handled specially. */
  235         if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
  236                 bcopy(dst->sa_data, &af, sizeof(af));
  237         else
  238                 af = dst->sa_family;
  239 
  240 #if 1   /* XXX */
  241         switch (af) {
  242         case AF_INET:
  243                 if (ifp->if_capenable & IFCAP_RXCSUM) {
  244                         m->m_pkthdr.csum_data = 0xffff;
  245                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  246                 }
  247                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
  248                 break;
  249         case AF_INET6:
  250 #if 0
  251                 /*
  252                  * XXX-BZ for now always claim the checksum is good despite
  253                  * any interface flags.   This is a workaround for 9.1-R and
  254                  * a proper solution ought to be sought later.
  255                  */
  256                 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
  257                         m->m_pkthdr.csum_data = 0xffff;
  258                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  259                 }
  260 #else
  261                 m->m_pkthdr.csum_data = 0xffff;
  262                 m->m_pkthdr.csum_flags = LO_CSUM_SET;
  263 #endif
  264                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
  265                 break;
  266         default:
  267                 printf("looutput: af=%d unexpected\n", af);
  268                 m_freem(m);
  269                 return (EAFNOSUPPORT);
  270         }
  271 #endif
  272         return (if_simloop(ifp, m, af, 0));
  273 }
  274 
  275 /*
  276  * if_simloop()
  277  *
  278  * This function is to support software emulation of hardware loopback,
  279  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
  280  * hear their own broadcasts, we create a copy of the packet that we
  281  * would normally receive via a hardware loopback.
  282  *
  283  * This function expects the packet to include the media header of length hlen.
  284  */
  285 int
  286 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
  287 {
  288         int isr;
  289 
  290         M_ASSERTPKTHDR(m);
  291         m_tag_delete_nonpersistent(m);
  292         m->m_pkthdr.rcvif = ifp;
  293 
  294 #ifdef MAC
  295         mac_ifnet_create_mbuf(ifp, m);
  296 #endif
  297 
  298         /*
  299          * Let BPF see incoming packet in the following manner:
  300          *  - Emulated packet loopback for a simplex interface
  301          *    (net/if_ethersubr.c)
  302          *      -> passes it to ifp's BPF
  303          *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
  304          *      -> not passes it to any BPF
  305          *  - Normal packet loopback from myself to myself (net/if_loop.c)
  306          *      -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
  307          */
  308         if (hlen > 0) {
  309                 if (bpf_peers_present(ifp->if_bpf)) {
  310                         bpf_mtap(ifp->if_bpf, m);
  311                 }
  312         } else {
  313                 if (bpf_peers_present(V_loif->if_bpf)) {
  314                         if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
  315                                 /* XXX beware sizeof(af) != 4 */
  316                                 u_int32_t af1 = af;
  317 
  318                                 /*
  319                                  * We need to prepend the address family.
  320                                  */
  321                                 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
  322                         }
  323                 }
  324         }
  325 
  326         /* Strip away media header */
  327         if (hlen > 0) {
  328                 m_adj(m, hlen);
  329 #ifndef __NO_STRICT_ALIGNMENT
  330                 /*
  331                  * Some archs do not like unaligned data, so
  332                  * we move data down in the first mbuf.
  333                  */
  334                 if (mtod(m, vm_offset_t) & 3) {
  335                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
  336                         bcopy(m->m_data,
  337                             (char *)(mtod(m, vm_offset_t)
  338                                 - (mtod(m, vm_offset_t) & 3)),
  339                             m->m_len);
  340                         m->m_data -= (mtod(m,vm_offset_t) & 3);
  341                 }
  342 #endif
  343         }
  344 
  345         /* Deliver to upper layer protocol */
  346         switch (af) {
  347 #ifdef INET
  348         case AF_INET:
  349                 isr = NETISR_IP;
  350                 break;
  351 #endif
  352 #ifdef INET6
  353         case AF_INET6:
  354                 m->m_flags |= M_LOOP;
  355                 isr = NETISR_IPV6;
  356                 break;
  357 #endif
  358         default:
  359                 printf("if_simloop: can't handle af=%d\n", af);
  360                 m_freem(m);
  361                 return (EAFNOSUPPORT);
  362         }
  363         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
  364         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
  365         netisr_queue(isr, m);   /* mbuf is free'd on failure. */
  366         return (0);
  367 }
  368 
  369 /*
  370  * Process an ioctl request.
  371  */
  372 /* ARGSUSED */
  373 int
  374 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  375 {
  376         struct ifreq *ifr = (struct ifreq *)data;
  377         int error = 0, mask;
  378 
  379         switch (cmd) {
  380         case SIOCSIFADDR:
  381                 ifp->if_flags |= IFF_UP;
  382                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
  383                 if_link_state_change(ifp, LINK_STATE_UP);
  384                 /*
  385                  * Everything else is done at a higher level.
  386                  */
  387                 break;
  388 
  389         case SIOCADDMULTI:
  390         case SIOCDELMULTI:
  391                 if (ifr == NULL) {
  392                         error = EAFNOSUPPORT;           /* XXX */
  393                         break;
  394                 }
  395                 switch (ifr->ifr_addr.sa_family) {
  396 
  397 #ifdef INET
  398                 case AF_INET:
  399                         break;
  400 #endif
  401 #ifdef INET6
  402                 case AF_INET6:
  403                         break;
  404 #endif
  405 
  406                 default:
  407                         error = EAFNOSUPPORT;
  408                         break;
  409                 }
  410                 break;
  411 
  412         case SIOCSIFMTU:
  413                 ifp->if_mtu = ifr->ifr_mtu;
  414                 break;
  415 
  416         case SIOCSIFFLAGS:
  417                 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
  418                     LINK_STATE_UP: LINK_STATE_DOWN);
  419                 break;
  420 
  421         case SIOCSIFCAP:
  422                 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
  423                 if ((mask & IFCAP_RXCSUM) != 0)
  424                         ifp->if_capenable ^= IFCAP_RXCSUM;
  425                 if ((mask & IFCAP_TXCSUM) != 0)
  426                         ifp->if_capenable ^= IFCAP_TXCSUM;
  427                 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
  428 #if 0
  429                         ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
  430 #else
  431                         error = EOPNOTSUPP;
  432                         break;
  433 #endif
  434                 }
  435                 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
  436 #if 0
  437                         ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
  438 #else
  439                         error = EOPNOTSUPP;
  440                         break;
  441 #endif
  442                 }
  443                 ifp->if_hwassist = 0;
  444                 if (ifp->if_capenable & IFCAP_TXCSUM)
  445                         ifp->if_hwassist = LO_CSUM_FEATURES;
  446 #if 0
  447                 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
  448                         ifp->if_hwassist |= LO_CSUM_FEATURES6;
  449 #endif
  450                 break;
  451 
  452         default:
  453                 error = EINVAL;
  454         }
  455         return (error);
  456 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_loop.c

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