sys/net/if_loop.c

   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
  32 /*
  33  * Loopback interface driver for protocol testing and timing.
  34  */
  35
  36 #include "opt_inet.h"
  37 #include "opt_inet6.h"
  38 #include "opt_rss.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_private.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 INET6
  67 #ifndef INET
  68 #include <netinet/in.h>
  69 #endif
  70 #include <netinet6/in6_var.h>
  71 #include <netinet/ip6.h>
  72 #endif
  73
  74 #include <security/mac/mac_framework.h>
  75
  76 #ifdef TINY_LOMTU
  77 #define LOMTU   (1024+512)
  78 #elif defined(LARGE_LOMTU)
  79 #define LOMTU   131072
  80 #else
  81 #define LOMTU   16384
  82 #endif
  83
  84 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
  85 #define LO_CSUM_FEATURES6       (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
  86 #define LO_CSUM_SET             (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
  87                                     CSUM_PSEUDO_HDR | \
  88                                     CSUM_IP_CHECKED | CSUM_IP_VALID | \
  89                                     CSUM_SCTP_VALID)
  90
  91 static int      loioctl(struct ifnet *, u_long, caddr_t);
  92 static int      looutput(struct ifnet *ifp, struct mbuf *m,
  93                     const struct sockaddr *dst, struct route *ro);
  94
  95 VNET_DEFINE(struct ifnet *, loif);      /* Used externally */
  96 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
  97 #define V_lo_cloner             VNET(lo_cloner)
  98
  99 static const char loname[] = "lo";
 100
 101 static int
 102 lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
 103 {
 104         if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
 105                 return (EINVAL);
 106
 107 #ifndef VIMAGE
 108         /* XXX: destroying lo0 will lead to panics. */
 109         KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
 110 #endif
 111
 112         bpfdetach(ifp);
 113         if_detach(ifp);
 114         if_free(ifp);
 115
 116         return (0);
 117 }
 118
 119 static int
 120 lo_clone_create(struct if_clone *ifc, char *name, size_t len,
 121     struct ifc_data *ifd, struct ifnet **ifpp)
 122 {
 123         struct ifnet *ifp;
 124
 125         ifp = if_alloc(IFT_LOOP);
 126         if_initname(ifp, loname, ifd->unit);
 127         ifp->if_mtu = LOMTU;
 128         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 129         ifp->if_ioctl = loioctl;
 130         ifp->if_output = looutput;
 131         ifp->if_snd.ifq_maxlen = ifqmaxlen;
 132         ifp->if_capabilities = ifp->if_capenable =
 133             IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
 134         ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
 135         if_attach(ifp);
 136         bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
 137         *ifpp = ifp;
 138
 139         return (0);
 140 }
 141
 142 static void
 143 vnet_loif_init(const void *unused __unused)
 144 {
 145         struct if_clone_addreq req = {
 146                 .create_f = lo_clone_create,
 147                 .destroy_f = lo_clone_destroy,
 148                 .flags = IFC_F_AUTOUNIT,
 149         };
 150         V_lo_cloner = ifc_attach_cloner(loname, &req);
 151         struct ifc_data ifd = { .unit = 0 };
 152         ifc_create_ifp(loname, &ifd, &V_loif);
 153 }
 154 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
 155     vnet_loif_init, NULL);
 156
 157 #ifdef VIMAGE
 158 static void
 159 vnet_loif_uninit(const void *unused __unused)
 160 {
 161
 162         ifc_detach_cloner(V_lo_cloner);
 163         V_loif = NULL;
 164 }
 165 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
 166     vnet_loif_uninit, NULL);
 167 #endif
 168
 169 static int
 170 loop_modevent(module_t mod, int type, void *data)
 171 {
 172
 173         switch (type) {
 174         case MOD_LOAD:
 175                 break;
 176
 177         case MOD_UNLOAD:
 178                 printf("loop module unload - not possible for this module type\n");
 179                 return (EINVAL);
 180
 181         default:
 182                 return (EOPNOTSUPP);
 183         }
 184         return (0);
 185 }
 186
 187 static moduledata_t loop_mod = {
 188         "if_lo",
 189         loop_modevent,
 190         0
 191 };
 192
 193 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
 194
 195 static int
 196 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 197     struct route *ro)
 198 {
 199         u_int32_t af;
 200 #ifdef MAC
 201         int error;
 202 #endif
 203
 204         M_ASSERTPKTHDR(m); /* check if we have the packet header */
 205
 206 #ifdef MAC
 207         error = mac_ifnet_check_transmit(ifp, m);
 208         if (error) {
 209                 m_freem(m);
 210                 return (error);
 211         }
 212 #endif
 213
 214         if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
 215                 m_freem(m);
 216                 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
 217         }
 218
 219         if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
 220         if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
 221
 222 #ifdef RSS
 223         M_HASHTYPE_CLEAR(m);
 224 #endif
 225
 226         /* BPF writes need to be handled specially. */
 227         if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
 228                 bcopy(dst->sa_data, &af, sizeof(af));
 229         else
 230                 af = RO_GET_FAMILY(ro, dst);
 231
 232 #if 1   /* XXX */
 233         switch (af) {
 234         case AF_INET:
 235                 if (ifp->if_capenable & IFCAP_RXCSUM) {
 236                         m->m_pkthdr.csum_data = 0xffff;
 237                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
 238                 }
 239                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
 240                 break;
 241         case AF_INET6:
 242 #if 0
 243                 /*
 244                  * XXX-BZ for now always claim the checksum is good despite
 245                  * any interface flags.   This is a workaround for 9.1-R and
 246                  * a proper solution ought to be sought later.
 247                  */
 248                 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
 249                         m->m_pkthdr.csum_data = 0xffff;
 250                         m->m_pkthdr.csum_flags = LO_CSUM_SET;
 251                 }
 252 #else
 253                 m->m_pkthdr.csum_data = 0xffff;
 254                 m->m_pkthdr.csum_flags = LO_CSUM_SET;
 255 #endif
 256                 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
 257                 break;
 258         default:
 259                 printf("looutput: af=%d unexpected\n", af);
 260                 m_freem(m);
 261                 return (EAFNOSUPPORT);
 262         }
 263 #endif
 264         return (if_simloop(ifp, m, af, 0));
 265 }
 266
 267 /*
 268  * if_simloop()
 269  *
 270  * This function is to support software emulation of hardware loopback,
 271  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 272  * hear their own broadcasts, we create a copy of the packet that we
 273  * would normally receive via a hardware loopback.
 274  *
 275  * This function expects the packet to include the media header of length hlen.
 276  */
 277 int
 278 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 279 {
 280         int isr;
 281
 282         M_ASSERTPKTHDR(m);
 283         m_tag_delete_nonpersistent(m);
 284         m->m_pkthdr.rcvif = ifp;
 285
 286 #ifdef MAC
 287         mac_ifnet_create_mbuf(ifp, m);
 288 #endif
 289
 290         /*
 291          * Let BPF see incoming packet in the following manner:
 292          *  - Emulated packet loopback for a simplex interface
 293          *    (net/if_ethersubr.c)
 294          *      -> passes it to ifp's BPF
 295          *  - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
 296          *      -> not passes it to any BPF
 297          *  - Normal packet loopback from myself to myself (net/if_loop.c)
 298          *      -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
 299          */
 300         if (hlen > 0) {
 301                 if (bpf_peers_present(ifp->if_bpf)) {
 302                         bpf_mtap(ifp->if_bpf, m);
 303                 }
 304         } else {
 305                 if (bpf_peers_present(V_loif->if_bpf)) {
 306                         if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
 307                                 /* XXX beware sizeof(af) != 4 */
 308                                 u_int32_t af1 = af;
 309
 310                                 /*
 311                                  * We need to prepend the address family.
 312                                  */
 313                                 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
 314                         }
 315                 }
 316         }
 317
 318         /* Strip away media header */
 319         if (hlen > 0) {
 320                 m_adj(m, hlen);
 321 #ifndef __NO_STRICT_ALIGNMENT
 322                 /*
 323                  * Some archs do not like unaligned data, so
 324                  * we move data down in the first mbuf.
 325                  */
 326                 if (mtod(m, vm_offset_t) & 3) {
 327                         KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
 328                         bcopy(m->m_data,
 329                             (char *)(mtod(m, vm_offset_t)
 330                                 - (mtod(m, vm_offset_t) & 3)),
 331                             m->m_len);
 332                         m->m_data -= (mtod(m,vm_offset_t) & 3);
 333                 }
 334 #endif
 335         }
 336
 337         /* Deliver to upper layer protocol */
 338         switch (af) {
 339 #ifdef INET
 340         case AF_INET:
 341                 isr = NETISR_IP;
 342                 break;
 343 #endif
 344 #ifdef INET6
 345         case AF_INET6:
 346                 m->m_flags |= M_LOOP;
 347                 isr = NETISR_IPV6;
 348                 break;
 349 #endif
 350         default:
 351                 printf("if_simloop: can't handle af=%d\n", af);
 352                 m_freem(m);
 353                 return (EAFNOSUPPORT);
 354         }
 355         if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
 356         if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
 357         netisr_queue(isr, m);   /* mbuf is free'd on failure. */
 358         return (0);
 359 }
 360
 361 /*
 362  * Process an ioctl request.
 363  */
 364 static int
 365 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 366 {
 367         struct ifreq *ifr = (struct ifreq *)data;
 368         int error = 0, mask;
 369
 370         switch (cmd) {
 371         case SIOCSIFADDR:
 372                 ifp->if_flags |= IFF_UP;
 373                 ifp->if_drv_flags |= IFF_DRV_RUNNING;
 374                 if_link_state_change(ifp, LINK_STATE_UP);
 375                 /*
 376                  * Everything else is done at a higher level.
 377                  */
 378                 break;
 379
 380         case SIOCADDMULTI:
 381         case SIOCDELMULTI:
 382                 if (ifr == NULL) {
 383                         error = EAFNOSUPPORT;           /* XXX */
 384                         break;
 385                 }
 386                 switch (ifr->ifr_addr.sa_family) {
 387 #ifdef INET
 388                 case AF_INET:
 389                         break;
 390 #endif
 391 #ifdef INET6
 392                 case AF_INET6:
 393                         break;
 394 #endif
 395
 396                 default:
 397                         error = EAFNOSUPPORT;
 398                         break;
 399                 }
 400                 break;
 401
 402         case SIOCSIFMTU:
 403                 ifp->if_mtu = ifr->ifr_mtu;
 404                 break;
 405
 406         case SIOCSIFFLAGS:
 407                 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
 408                     LINK_STATE_UP: LINK_STATE_DOWN);
 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 }