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/11.2/sys/net/if_loop.c 331722 2018-03-29 02:50:57Z eadler $
   31  */
   32 
   33 /*
   34  * Loopback interface driver for protocol testing and timing.
   35  */
   36 
   37 #include "opt_inet.h"
   38 #include "opt_inet6.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/kernel.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/module.h>
   45 #include <machine/bus.h>
   46 #include <sys/rman.h>
   47 #include <sys/socket.h>
   48 #include <sys/sockio.h>
   49 #include <sys/sysctl.h>
   50 
   51 #include <net/if.h>
   52 #include <net/if_var.h>
   53 #include <net/if_clone.h>
   54 #include <net/if_types.h>
   55 #include <net/netisr.h>
   56 #include <net/route.h>
   57 #include <net/bpf.h>
   58 #include <net/vnet.h>
   59 
   60 #ifdef  INET
   61 #include <netinet/in.h>
   62 #include <netinet/in_var.h>
   63 #endif
   64 
   65 #ifdef INET6
   66 #ifndef INET
   67 #include <netinet/in.h>
   68 #endif
   69 #include <netinet6/in6_var.h>
   70 #include <netinet/ip6.h>
   71 #endif
   72 
   73 #include <security/mac/mac_framework.h>
   74 
   75 #ifdef TINY_LOMTU
   76 #define LOMTU   (1024+512)
   77 #elif defined(LARGE_LOMTU)
   78 #define LOMTU   131072
   79 #else
   80 #define LOMTU   16384
   81 #endif
   82 
   83 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
   84 #define LO_CSUM_FEATURES6       (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
   85 #define LO_CSUM_SET             (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
   86                                     CSUM_PSEUDO_HDR | \
   87                                     CSUM_IP_CHECKED | CSUM_IP_VALID | \
   88                                     CSUM_SCTP_VALID)
   89 
   90 int             loioctl(struct ifnet *, u_long, caddr_t);
   91 int             looutput(struct ifnet *ifp, struct mbuf *m,
   92                     const struct sockaddr *dst, struct route *ro);
   93 static int      lo_clone_create(struct if_clone *, int, caddr_t);
   94 static void     lo_clone_destroy(struct ifnet *);
   95 
   96 VNET_DEFINE(struct ifnet *, loif);      /* Used externally */
   97 
   98 #ifdef VIMAGE
   99 static VNET_DEFINE(struct if_clone *, lo_cloner);
  100 #define V_lo_cloner             VNET(lo_cloner)
  101 #endif
  102 
  103 static struct if_clone *lo_cloner;
  104 static const char loname[] = "lo";
  105 
  106 static void
  107 lo_clone_destroy(struct ifnet *ifp)
  108 {
  109 
  110 #ifndef VIMAGE
  111         /* XXX: destroying lo0 will lead to panics. */
  112         KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
  113 #endif
  114 
  115         bpfdetach(ifp);
  116         if_detach(ifp);
  117         if_free(ifp);
  118 }
  119 
  120 static int
  121 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
  122 {
  123         struct ifnet *ifp;
  124 
  125         ifp = if_alloc(IFT_LOOP);
  126         if (ifp == NULL)
  127                 return (ENOSPC);
  128 
  129         if_initname(ifp, loname, unit);
  130         ifp->if_mtu = LOMTU;
  131         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
  132         ifp->if_ioctl = loioctl;
  133         ifp->if_output = looutput;
  134         ifp->if_snd.ifq_maxlen = ifqmaxlen;
  135         ifp->if_capabilities = ifp->if_capenable =
  136             IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
  137         ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
  138         if_attach(ifp);
  139         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
  140         if (V_loif == NULL)
  141                 V_loif = ifp;
  142 
  143         return (0);
  144 }
  145 
  146 static void
  147 vnet_loif_init(const void *unused __unused)
  148 {
  149 
  150 #ifdef VIMAGE
  151         lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
  152             1);
  153         V_lo_cloner = lo_cloner;
  154 #else
  155         lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
  156             1);
  157 #endif
  158 }
  159 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
  160     vnet_loif_init, NULL);
  161 
  162 #ifdef VIMAGE
  163 static void
  164 vnet_loif_uninit(const void *unused __unused)
  165 {
  166 
  167         if_clone_detach(V_lo_cloner);
  168         V_loif = NULL;
  169 }
  170 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
  171     vnet_loif_uninit, NULL);
  172 #endif
  173 
  174 static int
  175 loop_modevent(module_t mod, int type, void *data)
  176 {
  177 
  178         switch (type) {
  179         case MOD_LOAD:
  180                 break;
  181 
  182         case MOD_UNLOAD:
  183                 printf("loop module unload - not possible for this module type\n");
  184                 return (EINVAL);
  185 
  186         default:
  187                 return (EOPNOTSUPP);
  188         }
  189         return (0);
  190 }
  191 
  192 static moduledata_t loop_mod = {
  193         "if_lo",
  194         loop_modevent,
  195         0
  196 };
  197 
  198 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
  199 
  200 int
  201 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
  202     struct route *ro)
  203 {
  204         u_int32_t af;
  205 #ifdef MAC
  206         int error;
  207 #endif
  208 
  209         M_ASSERTPKTHDR(m); /* check if we have the packet header */
  210 
  211 #ifdef MAC
  212         error = mac_ifnet_check_transmit(ifp, m);
  213         if (error) {
  214                 m_freem(m);
  215                 return (error);
  216         }
  217 #endif
  218 
  219         if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
  220                 m_freem(m);
  221                 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
  222         }
  223 
  224         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
  225         if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
  226 
  227         /* BPF writes need to be handled specially. */
  228         if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
  229                 bcopy(dst->sa_data, &af, sizeof(af));
  230         else
  231                 af = dst->sa_family;
  232 
  233 #if 1   /* XXX */
  234         switch (af) {
  235         case AF_INET:
  236                 if (ifp->if_capenable & IFCAP_RXCSUM) {
  237                         m->m_pkthdr.csum_data = 0xffff;
  238                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  239                 }
  240                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
  241                 break;
  242         case AF_INET6:
  243 #if 0
  244                 /*
  245                  * XXX-BZ for now always claim the checksum is good despite
  246                  * any interface flags.   This is a workaround for 9.1-R and
  247                  * a proper solution ought to be sought later.
  248                  */
  249                 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
  250                         m->m_pkthdr.csum_data = 0xffff;
  251                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
  252                 }
  253 #else
  254                 m->m_pkthdr.csum_data = 0xffff;
  255                 m->m_pkthdr.csum_flags = LO_CSUM_SET;
  256 #endif
  257                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
  258                 break;
  259         default:
  260                 printf("looutput: af=%d unexpected\n", af);
  261                 m_freem(m);
  262                 return (EAFNOSUPPORT);
  263         }
  264 #endif
  265         return (if_simloop(ifp, m, af, 0));
  266 }
  267 
  268 /*
  269  * if_simloop()
  270  *
  271  * This function is to support software emulation of hardware loopback,
  272  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
  273  * hear their own broadcasts, we create a copy of the packet that we
  274  * would normally receive via a hardware loopback.
  275  *
  276  * This function expects the packet to include the media header of length hlen.
  277  */
  278 int
  279 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
  280 {
  281         int isr;
  282 
  283         M_ASSERTPKTHDR(m);
  284         m_tag_delete_nonpersistent(m);
  285         m->m_pkthdr.rcvif = ifp;
  286 
  287 #ifdef MAC
  288         mac_ifnet_create_mbuf(ifp, m);
  289 #endif
  290 
  291         /*
  292          * Let BPF see incoming packet in the following manner:
  293          *  - Emulated packet loopback for a simplex interface
  294          *    (net/if_ethersubr.c)
  295          *      -> passes it to ifp's BPF
  296          *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
  297          *      -> not passes it to any BPF
  298          *  - Normal packet loopback from myself to myself (net/if_loop.c)
  299          *      -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
  300          */
  301         if (hlen > 0) {
  302                 if (bpf_peers_present(ifp->if_bpf)) {
  303                         bpf_mtap(ifp->if_bpf, m);
  304                 }
  305         } else {
  306                 if (bpf_peers_present(V_loif->if_bpf)) {
  307                         if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
  308                                 /* XXX beware sizeof(af) != 4 */
  309                                 u_int32_t af1 = af;
  310 
  311                                 /*
  312                                  * We need to prepend the address family.
  313                                  */
  314                                 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
  315                         }
  316                 }
  317         }
  318 
  319         /* Strip away media header */
  320         if (hlen > 0) {
  321                 m_adj(m, hlen);
  322 #ifndef __NO_STRICT_ALIGNMENT
  323                 /*
  324                  * Some archs do not like unaligned data, so
  325                  * we move data down in the first mbuf.
  326                  */
  327                 if (mtod(m, vm_offset_t) & 3) {
  328                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
  329                         bcopy(m->m_data,
  330                             (char *)(mtod(m, vm_offset_t)
  331                                 - (mtod(m, vm_offset_t) & 3)),
  332                             m->m_len);
  333                         m->m_data -= (mtod(m,vm_offset_t) & 3);
  334                 }
  335 #endif
  336         }
  337 
  338         /* Deliver to upper layer protocol */
  339         switch (af) {
  340 #ifdef INET
  341         case AF_INET:
  342                 isr = NETISR_IP;
  343                 break;
  344 #endif
  345 #ifdef INET6
  346         case AF_INET6:
  347                 m->m_flags |= M_LOOP;
  348                 isr = NETISR_IPV6;
  349                 break;
  350 #endif
  351         default:
  352                 printf("if_simloop: can't handle af=%d\n", af);
  353                 m_freem(m);
  354                 return (EAFNOSUPPORT);
  355         }
  356         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
  357         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
  358         netisr_queue(isr, m);   /* mbuf is free'd on failure. */
  359         return (0);
  360 }
  361 
  362 /*
  363  * Process an ioctl request.
  364  */
  365 /* ARGSUSED */
  366 int
  367 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  368 {
  369         struct ifreq *ifr = (struct ifreq *)data;
  370         int error = 0, mask;
  371 
  372         switch (cmd) {
  373         case SIOCSIFADDR:
  374                 ifp->if_flags |= IFF_UP;
  375                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
  376                 /*
  377                  * Everything else is done at a higher level.
  378                  */
  379                 break;
  380 
  381         case SIOCADDMULTI:
  382         case SIOCDELMULTI:
  383                 if (ifr == NULL) {
  384                         error = EAFNOSUPPORT;           /* XXX */
  385                         break;
  386                 }
  387                 switch (ifr->ifr_addr.sa_family) {
  388 
  389 #ifdef INET
  390                 case AF_INET:
  391                         break;
  392 #endif
  393 #ifdef INET6
  394                 case AF_INET6:
  395                         break;
  396 #endif
  397 
  398                 default:
  399                         error = EAFNOSUPPORT;
  400                         break;
  401                 }
  402                 break;
  403 
  404         case SIOCSIFMTU:
  405                 ifp->if_mtu = ifr->ifr_mtu;
  406                 break;
  407 
  408         case SIOCSIFFLAGS:
  409                 break;
  410 
  411         case SIOCSIFCAP:
  412                 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
  413                 if ((mask & IFCAP_RXCSUM) != 0)
  414                         ifp->if_capenable ^= IFCAP_RXCSUM;
  415                 if ((mask & IFCAP_TXCSUM) != 0)
  416                         ifp->if_capenable ^= IFCAP_TXCSUM;
  417                 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
  418 #if 0
  419                         ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
  420 #else
  421                         error = EOPNOTSUPP;
  422                         break;
  423 #endif
  424                 }
  425                 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
  426 #if 0
  427                         ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
  428 #else
  429                         error = EOPNOTSUPP;
  430                         break;
  431 #endif
  432                 }
  433                 ifp->if_hwassist = 0;
  434                 if (ifp->if_capenable & IFCAP_TXCSUM)
  435                         ifp->if_hwassist = LO_CSUM_FEATURES;
  436 #if 0
  437                 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
  438                         ifp->if_hwassist |= LO_CSUM_FEATURES6;
  439 #endif
  440                 break;
  441 
  442         default:
  443                 error = EINVAL;
  444         }
  445         return (error);
  446 }
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FreeBSD/Linux Kernel Cross Reference sys/net/if_loop.c

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