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 1.47.2.8 2003/06/01 01:46:11 silby Exp $
  35  * $DragonFly: src/sys/net/if_loop.c,v 1.20 2006/12/22 23:44:54 swildner 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/mbuf.h>
  52 #include <sys/socket.h>
  53 #include <sys/sockio.h>
  54
  55 #include <net/if.h>
  56 #include <net/if_types.h>
  57 #include <net/ifq_var.h>
  58 #include <net/netisr.h>
  59 #include <net/route.h>
  60 #include <net/bpf.h>
  61 #include <net/bpfdesc.h>
  62
  63 #ifdef  INET
  64 #include <netinet/in.h>
  65 #include <netinet/in_var.h>
  66 #endif
  67
  68 #ifdef IPX
  69 #include <netproto/ipx/ipx.h>
  70 #include <netproto/ipx/ipx_if.h>
  71 #endif
  72
  73 #ifdef INET6
  74 #ifndef INET
  75 #include <netinet/in.h>
  76 #endif
  77 #include <netinet6/in6_var.h>
  78 #include <netinet/ip6.h>
  79 #endif
  80
  81 #ifdef NS
  82 #include <netns/ns.h>
  83 #include <netns/ns_if.h>
  84 #endif
  85
  86 #ifdef NETATALK
  87 #include <netproto/atalk/at.h>
  88 #include <netproto/atalk/at_var.h>
  89 #endif
  90
  91 int loioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
  92 static void lortrequest (int, struct rtentry *, struct rt_addrinfo *);
  93
  94 static void loopattach (void *);
  95 #ifdef ALTQ
  96 static void lo_altqstart(struct ifnet *);
  97 #endif
  98 PSEUDO_SET(loopattach, if_loop);
  99
 100 int looutput (struct ifnet *ifp,
 101                 struct mbuf *m, struct sockaddr *dst, struct rtentry *rt);
 102
 103 #ifdef TINY_LOMTU
 104 #define LOMTU   (1024+512)
 105 #elif defined(LARGE_LOMTU)
 106 #define LOMTU   131072
 107 #else
 108 #define LOMTU   16384
 109 #endif
 110
 111 struct  ifnet loif[NLOOP];
 112
 113 /* ARGSUSED */
 114 static void
 115 loopattach(void *dummy)
 116 {
 117         struct ifnet *ifp;
 118         int i;
 119
 120         for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) {
 121                 if_initname(ifp, "lo", i);
 122                 ifp->if_mtu = LOMTU;
 123                 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 124                 ifp->if_ioctl = loioctl;
 125                 ifp->if_output = looutput;
 126                 ifp->if_type = IFT_LOOP;
 127                 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 128                 ifq_set_ready(&ifp->if_snd);
 129 #ifdef ALTQ
 130                 ifp->if_start = lo_altqstart;
 131 #endif
 132                 if_attach(ifp, NULL);
 133                 bpfattach(ifp, DLT_NULL, sizeof(u_int));
 134         }
 135 }
 136
 137 int
 138 looutput(
 139         struct ifnet *ifp,
 140         struct mbuf *m,
 141         struct sockaddr *dst,
 142         struct rtentry *rt)
 143 {
 144         struct mbuf *n;
 145
 146         if ((m->m_flags & M_PKTHDR) == 0)
 147                 panic("looutput no HDR");
 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          * KAME requires that the packet to be contiguous on the
 156          * mbuf.  We need to make that sure.
 157          * this kind of code should be avoided.
 158          *
 159          * XXX: KAME may no longer need contiguous packets.  Once
 160          * that has been verified, the following code _should_ be
 161          * removed.
 162          */
 163         if (m && m->m_next != NULL) {
 164
 165                 n = m_defrag(m, MB_DONTWAIT);
 166
 167                 if (n == NULL) {
 168                         m_freem(m);
 169                         return (ENOBUFS);
 170                 } else {
 171                         m = n;
 172                 }
 173         }
 174
 175         ifp->if_opackets++;
 176         ifp->if_obytes += m->m_pkthdr.len;
 177 #if 1   /* XXX */
 178         switch (dst->sa_family) {
 179         case AF_INET:
 180         case AF_INET6:
 181         case AF_IPX:
 182         case AF_NS:
 183         case AF_APPLETALK:
 184                 break;
 185         default:
 186                 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
 187                 m_freem(m);
 188                 return (EAFNOSUPPORT);
 189         }
 190 #endif
 191         return (if_simloop(ifp, m, dst->sa_family, 0));
 192 }
 193
 194 /*
 195  * if_simloop()
 196  *
 197  * This function is to support software emulation of hardware loopback,
 198  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 199  * hear their own broadcasts, we create a copy of the packet that we
 200  * would normally receive via a hardware loopback.
 201  *
 202  * This function expects the packet to include the media header of length hlen.
 203  */
 204 int
 205 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 206 {
 207         int isr;
 208
 209         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 210         m->m_pkthdr.rcvif = ifp;
 211
 212         /* BPF write needs to be handled specially */
 213         if (af == AF_UNSPEC) {
 214                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 215                 af = *(mtod(m, int *));
 216                 m->m_len -= sizeof(int);
 217                 m->m_pkthdr.len -= sizeof(int);
 218                 m->m_data += sizeof(int);
 219         }
 220
 221         if (ifp->if_bpf) {
 222                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 223                         uint32_t bpf_af = (uint32_t)af;
 224                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 225                 }
 226                 else {
 227                         bpf_mtap(ifp->if_bpf, m);
 228                 }
 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                 (*ifp->if_start)(ifp);
 266                 crit_exit();
 267                 return (error);
 268         }
 269 #endif /* ALTQ */
 270
 271         /* Deliver to upper layer protocol */
 272         switch (af) {
 273 #ifdef INET
 274         case AF_INET:
 275                 isr = NETISR_IP;
 276                 break;
 277 #endif
 278 #ifdef INET6
 279         case AF_INET6:
 280                 m->m_flags |= M_LOOP;
 281                 isr = NETISR_IPV6;
 282                 break;
 283 #endif
 284 #ifdef IPX
 285         case AF_IPX:
 286                 isr = NETISR_IPX;
 287                 break;
 288 #endif
 289 #ifdef NS
 290         case AF_NS:
 291                 isr = NETISR_NS;
 292                 break;
 293 #endif
 294 #ifdef NETATALK
 295         case AF_APPLETALK:
 296                 isr = NETISR_ATALK2;
 297                 break;
 298 #endif
 299         default:
 300                 kprintf("if_simloop: can't handle af=%d\n", af);
 301                 m_freem(m);
 302                 return (EAFNOSUPPORT);
 303         }
 304
 305         ifp->if_ipackets++;
 306         ifp->if_ibytes += m->m_pkthdr.len;
 307         netisr_queue(isr, m);
 308         return (0);
 309 }
 310
 311 #ifdef ALTQ
 312 static void
 313 lo_altqstart(struct ifnet *ifp)
 314 {
 315         struct mbuf *m;
 316         int32_t af, *afp;
 317         int isr;
 318
 319         while (1) {
 320                 crit_enter();
 321                 m = ifq_dequeue(&ifp->if_snd, NULL);
 322                 crit_exit();
 323                 if (m == NULL)
 324                         return;
 325
 326                 afp = mtod(m, int32_t *);
 327                 af = *afp;
 328                 m_adj(m, sizeof(int32_t));
 329
 330                 switch (af) {
 331 #ifdef INET
 332                 case AF_INET:
 333                         isr = NETISR_IP;
 334                         break;
 335 #endif
 336 #ifdef INET6
 337                 case AF_INET6:
 338                         m->m_flags |= M_LOOP;
 339                         isr = NETISR_IPV6;
 340                         break;
 341 #endif
 342 #ifdef IPX
 343                 case AF_IPX:
 344                         isr = NETISR_IPX;
 345                         break;
 346 #endif
 347 #ifdef NS
 348                 case AF_NS:
 349                         isr = NETISR_NS;
 350                         break;
 351 #endif
 352 #ifdef ISO
 353                 case AF_ISO:
 354                         isr = NETISR_ISO;
 355                         break;
 356 #endif
 357 #ifdef NETATALK
 358                 case AF_APPLETALK:
 359                         isr = NETISR_ATALK2;
 360                         break;
 361 #endif
 362                 default:
 363                         kprintf("lo_altqstart: can't handle af%d\n", af);
 364                         m_freem(m);
 365                         return;
 366                 }
 367
 368                 ifp->if_ipackets++;
 369                 ifp->if_ibytes += m->m_pkthdr.len;
 370                 netisr_queue(isr, m);
 371         }
 372 }
 373 #endif /* ALTQ */
 374
 375 /* ARGSUSED */
 376 static void
 377 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
 378 {
 379         if (rt) {
 380                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 381                 /*
 382                  * For optimal performance, the send and receive buffers
 383                  * should be at least twice the MTU plus a little more for
 384                  * overhead.
 385                  */
 386                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 387         }
 388 }
 389
 390 /*
 391  * Process an ioctl request.
 392  */
 393 /* ARGSUSED */
 394 int
 395 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 396 {
 397         struct ifaddr *ifa;
 398         struct ifreq *ifr = (struct ifreq *)data;
 399         int error = 0;
 400
 401         switch (cmd) {
 402
 403         case SIOCSIFADDR:
 404                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 405                 ifa = (struct ifaddr *)data;
 406                 ifa->ifa_rtrequest = lortrequest;
 407                 /*
 408                  * Everything else is done at a higher level.
 409                  */
 410                 break;
 411
 412         case SIOCADDMULTI:
 413         case SIOCDELMULTI:
 414                 if (ifr == 0) {
 415                         error = EAFNOSUPPORT;           /* XXX */
 416                         break;
 417                 }
 418                 switch (ifr->ifr_addr.sa_family) {
 419
 420 #ifdef INET
 421                 case AF_INET:
 422                         break;
 423 #endif
 424 #ifdef INET6
 425                 case AF_INET6:
 426                         break;
 427 #endif
 428
 429                 default:
 430                         error = EAFNOSUPPORT;
 431                         break;
 432                 }
 433                 break;
 434
 435         case SIOCSIFMTU:
 436                 ifp->if_mtu = ifr->ifr_mtu;
 437                 break;
 438
 439         case SIOCSIFFLAGS:
 440                 break;
 441
 442         default:
 443                 error = EINVAL;
 444         }
 445         return (error);
 446 }