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 <net/if.h>
  57 #include <net/if_types.h>
  58 #include <net/ifq_var.h>
  59 #include <net/netisr.h>
  60 #include <net/route.h>
  61 #include <net/bpf.h>
  62 #include <net/bpfdesc.h>
  63
  64 #ifdef  INET
  65 #include <netinet/in.h>
  66 #include <netinet/in_var.h>
  67 #endif
  68
  69 #ifdef IPX
  70 #include <netproto/ipx/ipx.h>
  71 #include <netproto/ipx/ipx_if.h>
  72 #endif
  73
  74 #ifdef INET6
  75 #ifndef INET
  76 #include <netinet/in.h>
  77 #endif
  78 #include <netinet6/in6_var.h>
  79 #include <netinet/ip6.h>
  80 #endif
  81
  82 #ifdef NS
  83 #include <netns/ns.h>
  84 #include <netns/ns_if.h>
  85 #endif
  86
  87 #ifdef NETATALK
  88 #include <netproto/atalk/at.h>
  89 #include <netproto/atalk/at_var.h>
  90 #endif
  91
  92 static void     loopattach(void *);
  93 static int      looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
  94                          struct rtentry *);
  95 static int      loioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
  96 static void     lortrequest(int, struct rtentry *, struct rt_addrinfo *);
  97 #ifdef ALTQ
  98 static void     lo_altqstart(struct ifnet *);
  99 #endif
 100 PSEUDO_SET(loopattach, if_loop);
 101
 102 #ifdef TINY_LOMTU
 103 #define LOMTU   (1024+512)
 104 #elif defined(LARGE_LOMTU)
 105 #define LOMTU   131072
 106 #else
 107 #define LOMTU   16384
 108 #endif
 109
 110 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_UDP | CSUM_TCP)
 111
 112 struct  ifnet loif[NLOOP];
 113
 114 /* ARGSUSED */
 115 static void
 116 loopattach(void *dummy)
 117 {
 118         struct ifnet *ifp;
 119         int i;
 120
 121         for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) {
 122                 if_initname(ifp, "lo", i);
 123                 ifp->if_mtu = LOMTU;
 124                 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 125                 ifp->if_capabilities = IFCAP_HWCSUM;
 126                 ifp->if_hwassist = LO_CSUM_FEATURES;
 127                 ifp->if_capenable = ifp->if_capabilities;
 128                 ifp->if_ioctl = loioctl;
 129                 ifp->if_output = looutput;
 130                 ifp->if_type = IFT_LOOP;
 131                 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 132                 ifq_set_ready(&ifp->if_snd);
 133 #ifdef ALTQ
 134                 ifp->if_start = lo_altqstart;
 135 #endif
 136                 if_attach(ifp, NULL);
 137                 bpfattach(ifp, DLT_NULL, sizeof(u_int));
 138         }
 139 }
 140
 141 static int
 142 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 143          struct rtentry *rt)
 144 {
 145         M_ASSERTPKTHDR(m);
 146
 147         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 148                 m_freem(m);
 149                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 150                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 151         }
 152
 153         ifp->if_opackets++;
 154         ifp->if_obytes += m->m_pkthdr.len;
 155 #if 1   /* XXX */
 156         switch (dst->sa_family) {
 157         case AF_INET:
 158         case AF_INET6:
 159         case AF_IPX:
 160         case AF_NS:
 161         case AF_APPLETALK:
 162                 break;
 163         default:
 164                 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
 165                 m_freem(m);
 166                 return (EAFNOSUPPORT);
 167         }
 168 #endif
 169
 170         if (ifp->if_capenable & IFCAP_RXCSUM) {
 171                 int csum_flags = 0;
 172
 173                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 174                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 175                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 176                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 177
 178                 m->m_pkthdr.csum_flags |= csum_flags;
 179                 if (csum_flags & CSUM_DATA_VALID)
 180                         m->m_pkthdr.csum_data = 0xffff;
 181         }
 182         return (if_simloop(ifp, m, dst->sa_family, 0));
 183 }
 184
 185 /*
 186  * if_simloop()
 187  *
 188  * This function is to support software emulation of hardware loopback,
 189  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 190  * hear their own broadcasts, we create a copy of the packet that we
 191  * would normally receive via a hardware loopback.
 192  *
 193  * This function expects the packet to include the media header of length hlen.
 194  */
 195 int
 196 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 197 {
 198         int isr;
 199
 200         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 201         m->m_pkthdr.rcvif = ifp;
 202
 203         /* BPF write needs to be handled specially */
 204         if (af == AF_UNSPEC) {
 205                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 206                 af = *(mtod(m, int *));
 207                 m->m_len -= sizeof(int);
 208                 m->m_pkthdr.len -= sizeof(int);
 209                 m->m_data += sizeof(int);
 210         }
 211
 212         if (ifp->if_bpf) {
 213                 get_mplock();
 214
 215                 /* Re-check */
 216                 if (ifp->if_bpf == NULL)
 217                         goto rel;
 218
 219                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 220                         uint32_t bpf_af = (uint32_t)af;
 221                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 222                 } else {
 223                         bpf_mtap(ifp->if_bpf, m);
 224                 }
 225 rel:
 226                 rel_mplock();
 227         }
 228
 229         /* Strip away media header */
 230         if (hlen > 0)
 231                 m_adj(m, hlen);
 232
 233 #ifdef ALTQ
 234         /*
 235          * altq for loop is just for debugging.
 236          * only used when called for loop interface (not for
 237          * a simplex interface).
 238          */
 239         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 240                 struct altq_pktattr pktattr;
 241                 int32_t *afp;
 242                 int error;
 243
 244                 /*
 245                  * if the queueing discipline needs packet classification,
 246                  * do it before prepending link headers.
 247                  */
 248                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 249
 250                 M_PREPEND(m, sizeof(int32_t), MB_DONTWAIT);
 251                 if (m == 0)
 252                         return(ENOBUFS);
 253                 afp = mtod(m, int32_t *);
 254                 *afp = (int32_t)af;
 255
 256                 /*
 257                  * A critical section is needed for subsystems protected by
 258                  * the MP lock, and the serializer is assumed to already
 259                  * be held for MPSAFE subsystems.
 260                  */
 261                 crit_enter();
 262                 error = ifq_enqueue(&ifp->if_snd, m, &pktattr);
 263                 lwkt_serialize_enter(ifp->if_serializer);
 264                 ifp->if_start(ifp);
 265                 lwkt_serialize_exit(ifp->if_serializer);
 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 static 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, mask;
 400
 401         switch (cmd) {
 402         case SIOCSIFADDR:
 403                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 404                 ifa = (struct ifaddr *)data;
 405                 ifa->ifa_rtrequest = lortrequest;
 406                 /*
 407                  * Everything else is done at a higher level.
 408                  */
 409                 break;
 410
 411         case SIOCADDMULTI:
 412         case SIOCDELMULTI:
 413                 if (ifr == 0) {
 414                         error = EAFNOSUPPORT;           /* XXX */
 415                         break;
 416                 }
 417                 switch (ifr->ifr_addr.sa_family) {
 418
 419 #ifdef INET
 420                 case AF_INET:
 421                         break;
 422 #endif
 423 #ifdef INET6
 424                 case AF_INET6:
 425                         break;
 426 #endif
 427
 428                 default:
 429                         error = EAFNOSUPPORT;
 430                         break;
 431                 }
 432                 break;
 433
 434         case SIOCSIFMTU:
 435                 ifp->if_mtu = ifr->ifr_mtu;
 436                 break;
 437
 438         case SIOCSIFFLAGS:
 439                 break;
 440
 441         case SIOCSIFCAP:
 442                 mask = (ifr->ifr_reqcap ^ ifp->if_capenable) & IFCAP_HWCSUM;
 443                 if (mask) {
 444                         ifp->if_capenable ^= mask;
 445                         if (IFCAP_TXCSUM & ifp->if_capenable)
 446                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 447                         else
 448                                 ifp->if_hwassist = 0;
 449                 }
 450                 break;
 451
 452         default:
 453                 error = EINVAL;
 454         }
 455         return (error);
 456 }