sys/net/if_loop.c

   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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)if_loop.c   8.1 (Berkeley) 6/10/93
  34  * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $
  35  * $DragonFly: src/sys/net/if_loop.c,v 1.26 2008/10/04 11:21:10 sephe Exp $
  36  */
  37
  38 /*
  39  * Loopback interface driver for protocol testing and timing.
  40  */
  41 #include "use_loop.h"
  42
  43 #include "opt_atalk.h"
  44 #include "opt_inet.h"
  45 #include "opt_inet6.h"
  46 #include "opt_ipx.h"
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/kernel.h>
  51 #include <sys/lock.h>
  52 #include <sys/mbuf.h>
  53 #include <sys/socket.h>
  54 #include <sys/sockio.h>
  55
  56 #include <sys/mplock2.h>
  57
  58 #include <net/if.h>
  59 #include <net/if_types.h>
  60 #include <net/ifq_var.h>
  61 #include <net/netisr.h>
  62 #include <net/route.h>
  63 #include <net/bpf.h>
  64 #include <net/bpfdesc.h>
  65
  66 #ifdef  INET
  67 #include <netinet/in.h>
  68 #include <netinet/in_var.h>
  69 #endif
  70
  71 #ifdef IPX
  72 #include <netproto/ipx/ipx.h>
  73 #include <netproto/ipx/ipx_if.h>
  74 #endif
  75
  76 #ifdef INET6
  77 #ifndef INET
  78 #include <netinet/in.h>
  79 #endif
  80 #include <netinet6/in6_var.h>
  81 #include <netinet/ip6.h>
  82 #endif
  83
  84 #ifdef NS
  85 #include <netns/ns.h>
  86 #include <netns/ns_if.h>
  87 #endif
  88
  89 #ifdef NETATALK
  90 #include <netproto/atalk/at.h>
  91 #include <netproto/atalk/at_var.h>
  92 #endif
  93
  94 static void     loopattach(void *);
  95 static int      looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
  96                          struct rtentry *);
  97 static int      loioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
  98 static void     lortrequest(int, struct rtentry *, struct rt_addrinfo *);
  99 #ifdef ALTQ
 100 static void     lo_altqstart(struct ifnet *);
 101 #endif
 102 PSEUDO_SET(loopattach, if_loop);
 103
 104 #ifdef TINY_LOMTU
 105 #define LOMTU   (1024+512)
 106 #elif defined(LARGE_LOMTU)
 107 #define LOMTU   131072
 108 #else
 109 #define LOMTU   16384
 110 #endif
 111
 112 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_UDP | CSUM_TCP)
 113
 114 struct  ifnet loif[NLOOP];
 115
 116 /* ARGSUSED */
 117 static void
 118 loopattach(void *dummy)
 119 {
 120         struct ifnet *ifp;
 121         int i;
 122
 123         for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) {
 124                 if_initname(ifp, "lo", i);
 125                 ifp->if_mtu = LOMTU;
 126                 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 127                 ifp->if_capabilities = IFCAP_HWCSUM;
 128                 ifp->if_hwassist = LO_CSUM_FEATURES;
 129                 ifp->if_capenable = ifp->if_capabilities;
 130                 ifp->if_ioctl = loioctl;
 131                 ifp->if_output = looutput;
 132                 ifp->if_type = IFT_LOOP;
 133                 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 134                 ifq_set_ready(&ifp->if_snd);
 135 #ifdef ALTQ
 136                 ifp->if_start = lo_altqstart;
 137 #endif
 138                 if_attach(ifp, NULL);
 139                 bpfattach(ifp, DLT_NULL, sizeof(u_int));
 140         }
 141 }
 142
 143 static int
 144 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 145          struct rtentry *rt)
 146 {
 147         M_ASSERTPKTHDR(m);
 148
 149         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 150                 m_freem(m);
 151                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 152                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 153         }
 154
 155         ifp->if_opackets++;
 156         ifp->if_obytes += m->m_pkthdr.len;
 157 #if 1   /* XXX */
 158         switch (dst->sa_family) {
 159         case AF_INET:
 160         case AF_INET6:
 161         case AF_IPX:
 162         case AF_NS:
 163         case AF_APPLETALK:
 164                 break;
 165         default:
 166                 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
 167                 m_freem(m);
 168                 return (EAFNOSUPPORT);
 169         }
 170 #endif
 171
 172         if (ifp->if_capenable & IFCAP_RXCSUM) {
 173                 int csum_flags = 0;
 174
 175                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 176                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 177                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 178                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 179
 180                 m->m_pkthdr.csum_flags |= csum_flags;
 181                 if (csum_flags & CSUM_DATA_VALID)
 182                         m->m_pkthdr.csum_data = 0xffff;
 183         }
 184         return (if_simloop(ifp, m, dst->sa_family, 0));
 185 }
 186
 187 /*
 188  * if_simloop()
 189  *
 190  * This function is to support software emulation of hardware loopback,
 191  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 192  * hear their own broadcasts, we create a copy of the packet that we
 193  * would normally receive via a hardware loopback.
 194  *
 195  * This function expects the packet to include the media header of length hlen.
 196  */
 197 int
 198 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 199 {
 200         int isr;
 201
 202         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 203         m->m_pkthdr.rcvif = ifp;
 204
 205         /* BPF write needs to be handled specially */
 206         if (af == AF_UNSPEC) {
 207                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 208                 af = *(mtod(m, int *));
 209                 m->m_len -= sizeof(int);
 210                 m->m_pkthdr.len -= sizeof(int);
 211                 m->m_data += sizeof(int);
 212         }
 213
 214         if (ifp->if_bpf) {
 215                 get_mplock();
 216
 217                 /* Re-check */
 218                 if (ifp->if_bpf == NULL)
 219                         goto rel;
 220
 221                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 222                         uint32_t bpf_af = (uint32_t)af;
 223                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 224                 } else {
 225                         bpf_mtap(ifp->if_bpf, m);
 226                 }
 227 rel:
 228                 rel_mplock();
 229         }
 230
 231         /* Strip away media header */
 232         if (hlen > 0)
 233                 m_adj(m, hlen);
 234
 235 #ifdef ALTQ
 236         /*
 237          * altq for loop is just for debugging.
 238          * only used when called for loop interface (not for
 239          * a simplex interface).
 240          */
 241         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 242                 struct altq_pktattr pktattr;
 243                 int32_t *afp;
 244                 int error;
 245
 246                 /*
 247                  * if the queueing discipline needs packet classification,
 248                  * do it before prepending link headers.
 249                  */
 250                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 251
 252                 M_PREPEND(m, sizeof(int32_t), MB_DONTWAIT);
 253                 if (m == 0)
 254                         return(ENOBUFS);
 255                 afp = mtod(m, int32_t *);
 256                 *afp = (int32_t)af;
 257
 258                 /*
 259                  * A critical section is needed for subsystems protected by
 260                  * the MP lock, and the serializer is assumed to already
 261                  * be held for MPSAFE subsystems.
 262                  */
 263                 crit_enter();
 264                 error = ifq_enqueue(&ifp->if_snd, m, &pktattr);
 265                 ifnet_serialize_tx(ifp);
 266                 ifp->if_start(ifp);
 267                 ifnet_deserialize_tx(ifp);
 268                 crit_exit();
 269                 return (error);
 270         }
 271 #endif /* ALTQ */
 272
 273         /* Deliver to upper layer protocol */
 274         switch (af) {
 275 #ifdef INET
 276         case AF_INET:
 277                 isr = NETISR_IP;
 278                 break;
 279 #endif
 280 #ifdef INET6
 281         case AF_INET6:
 282                 m->m_flags |= M_LOOP;
 283                 isr = NETISR_IPV6;
 284                 break;
 285 #endif
 286 #ifdef IPX
 287         case AF_IPX:
 288                 isr = NETISR_IPX;
 289                 break;
 290 #endif
 291 #ifdef NS
 292         case AF_NS:
 293                 isr = NETISR_NS;
 294                 break;
 295 #endif
 296 #ifdef NETATALK
 297         case AF_APPLETALK:
 298                 isr = NETISR_ATALK2;
 299                 break;
 300 #endif
 301         default:
 302                 kprintf("if_simloop: can't handle af=%d\n", af);
 303                 m_freem(m);
 304                 return (EAFNOSUPPORT);
 305         }
 306
 307         ifp->if_ipackets++;
 308         ifp->if_ibytes += m->m_pkthdr.len;
 309         netisr_queue(isr, m);
 310         return (0);
 311 }
 312
 313 #ifdef ALTQ
 314 static void
 315 lo_altqstart(struct ifnet *ifp)
 316 {
 317         struct mbuf *m;
 318         int32_t af, *afp;
 319         int isr;
 320
 321         while (1) {
 322                 crit_enter();
 323                 m = ifq_dequeue(&ifp->if_snd, NULL);
 324                 crit_exit();
 325                 if (m == NULL)
 326                         return;
 327
 328                 afp = mtod(m, int32_t *);
 329                 af = *afp;
 330                 m_adj(m, sizeof(int32_t));
 331
 332                 switch (af) {
 333 #ifdef INET
 334                 case AF_INET:
 335                         isr = NETISR_IP;
 336                         break;
 337 #endif
 338 #ifdef INET6
 339                 case AF_INET6:
 340                         m->m_flags |= M_LOOP;
 341                         isr = NETISR_IPV6;
 342                         break;
 343 #endif
 344 #ifdef IPX
 345                 case AF_IPX:
 346                         isr = NETISR_IPX;
 347                         break;
 348 #endif
 349 #ifdef NS
 350                 case AF_NS:
 351                         isr = NETISR_NS;
 352                         break;
 353 #endif
 354 #ifdef ISO
 355                 case AF_ISO:
 356                         isr = NETISR_ISO;
 357                         break;
 358 #endif
 359 #ifdef NETATALK
 360                 case AF_APPLETALK:
 361                         isr = NETISR_ATALK2;
 362                         break;
 363 #endif
 364                 default:
 365                         kprintf("lo_altqstart: can't handle af%d\n", af);
 366                         m_freem(m);
 367                         return;
 368                 }
 369
 370                 ifp->if_ipackets++;
 371                 ifp->if_ibytes += m->m_pkthdr.len;
 372                 netisr_queue(isr, m);
 373         }
 374 }
 375 #endif /* ALTQ */
 376
 377 /* ARGSUSED */
 378 static void
 379 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
 380 {
 381         if (rt) {
 382                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 383                 /*
 384                  * For optimal performance, the send and receive buffers
 385                  * should be at least twice the MTU plus a little more for
 386                  * overhead.
 387                  */
 388                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 389         }
 390 }
 391
 392 /*
 393  * Process an ioctl request.
 394  */
 395 /* ARGSUSED */
 396 static int
 397 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 398 {
 399         struct ifaddr *ifa;
 400         struct ifreq *ifr = (struct ifreq *)data;
 401         int error = 0, mask;
 402
 403         switch (cmd) {
 404         case SIOCSIFADDR:
 405                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 406                 ifa = (struct ifaddr *)data;
 407                 ifa->ifa_rtrequest = lortrequest;
 408                 /*
 409                  * Everything else is done at a higher level.
 410                  */
 411                 break;
 412
 413         case SIOCADDMULTI:
 414         case SIOCDELMULTI:
 415                 if (ifr == 0) {
 416                         error = EAFNOSUPPORT;           /* XXX */
 417                         break;
 418                 }
 419                 switch (ifr->ifr_addr.sa_family) {
 420
 421 #ifdef INET
 422                 case AF_INET:
 423                         break;
 424 #endif
 425 #ifdef INET6
 426                 case AF_INET6:
 427                         break;
 428 #endif
 429
 430                 default:
 431                         error = EAFNOSUPPORT;
 432                         break;
 433                 }
 434                 break;
 435
 436         case SIOCSIFMTU:
 437                 ifp->if_mtu = ifr->ifr_mtu;
 438                 break;
 439
 440         case SIOCSIFFLAGS:
 441                 break;
 442
 443         case SIOCSIFCAP:
 444                 mask = (ifr->ifr_reqcap ^ ifp->if_capenable) & IFCAP_HWCSUM;
 445                 if (mask) {
 446                         ifp->if_capenable ^= mask;
 447                         if (IFCAP_TXCSUM & ifp->if_capenable)
 448                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 449                         else
 450                                 ifp->if_hwassist = 0;
 451                 }
 452                 break;
 453
 454         default:
 455                 error = EINVAL;
 456         }
 457         return (error);
 458 }