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. 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   8.1 (Berkeley) 6/10/93
  30  * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $
  31  */
  32
  33 /*
  34  * Loopback interface driver for protocol testing and timing.
  35  */
  36 #include "use_loop.h"
  37
  38 #include "opt_inet.h"
  39 #include "opt_inet6.h"
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/lock.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/socket.h>
  47 #include <sys/sockio.h>
  48
  49 #include <sys/mplock2.h>
  50
  51 #include <net/if.h>
  52 #include <net/if_types.h>
  53 #include <net/if_clone.h>
  54 #include <net/ifq_var.h>
  55 #include <net/netisr.h>
  56 #include <net/route.h>
  57 #include <net/bpf.h>
  58 #include <net/bpfdesc.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 static int      lo_clone_create(struct if_clone *, int, caddr_t);
  74 static int      lo_clone_destroy(struct ifnet *);
  75
  76 static int      lo_output(struct ifnet *, struct mbuf *, struct sockaddr *,
  77                     struct rtentry *);
  78 static int      lo_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
  79 static void     lo_rtrequest(int, struct rtentry *);
  80 #ifdef ALTQ
  81 static void     lo_altqstart(struct ifnet *, struct ifaltq_subque *);
  82 #endif
  83
  84 #if defined(TINY_LOMTU)
  85 #define LOMTU   (1024+512)
  86 #elif defined(LARGE_LOMTU)
  87 #define LOMTU   131072
  88 #else
  89 #define LOMTU   16384
  90 #endif
  91
  92 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_UDP | CSUM_TCP)
  93
  94 struct ifnet    *loif;
  95
  96 static struct if_clone lo_cloner = IF_CLONE_INITIALIZER("lo",
  97     lo_clone_create, lo_clone_destroy, NLOOP, IF_MAXUNIT);
  98
  99 static void
 100 lo_sysinit(void *dummy __unused)
 101 {
 102         if_clone_attach(&lo_cloner);
 103 }
 104 SYSINIT(lo_sysinit, SI_SUB_PSEUDO, SI_ORDER_ANY, lo_sysinit, NULL);
 105
 106 static int
 107 lo_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused)
 108 {
 109         struct ifnet *ifp;
 110
 111         ifp = kmalloc(sizeof(*ifp), M_IFNET, M_WAITOK | M_ZERO);
 112         if_initname(ifp, ifc->ifc_name, unit);
 113         ifp->if_mtu = LOMTU;
 114         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 115         ifp->if_capabilities = IFCAP_HWCSUM | IFCAP_RSS;
 116         ifp->if_hwassist = LO_CSUM_FEATURES;
 117         ifp->if_capenable = ifp->if_capabilities;
 118         ifp->if_ioctl = lo_ioctl;
 119         ifp->if_output = lo_output;
 120         ifp->if_type = IFT_LOOP;
 121         ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 122         ifq_set_ready(&ifp->if_snd);
 123 #ifdef ALTQ
 124         ifp->if_start = lo_altqstart;
 125 #endif
 126         if_attach(ifp, NULL);
 127         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 128
 129         if (loif == NULL) {
 130                 KASSERT(unit == 0, ("loif is %s", ifp->if_xname));
 131                 loif = ifp;
 132         }
 133         return (0);
 134 }
 135
 136 static int
 137 lo_clone_destroy(struct ifnet *ifp)
 138 {
 139         if (loif == ifp)
 140                 return (EPERM);
 141
 142         bpfdetach(ifp);
 143         if_detach(ifp);
 144         kfree(ifp, M_IFNET);
 145         return (0);
 146 }
 147
 148 static int
 149 lo_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 150     struct rtentry *rt)
 151 {
 152         M_ASSERTPKTHDR(m);
 153
 154         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 155                 m_freem(m);
 156                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 157                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 158         }
 159
 160         IFNET_STAT_INC(ifp, opackets, 1);
 161         IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len);
 162 #if 1   /* XXX */
 163         switch (dst->sa_family) {
 164         case AF_INET:
 165         case AF_INET6:
 166                 break;
 167         default:
 168                 kprintf("lo_output: af=%d unexpected\n", dst->sa_family);
 169                 m_freem(m);
 170                 return (EAFNOSUPPORT);
 171         }
 172 #endif
 173
 174         if (ifp->if_capenable & IFCAP_RXCSUM) {
 175                 int csum_flags = 0;
 176
 177                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 178                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 179                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 180                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 181
 182                 m->m_pkthdr.csum_flags |= csum_flags;
 183                 if (csum_flags & CSUM_DATA_VALID)
 184                         m->m_pkthdr.csum_data = 0xffff;
 185         }
 186         if ((ifp->if_capenable & IFCAP_RSS) == 0)
 187                 m->m_flags &= ~M_HASH;
 188         return (if_simloop(ifp, m, dst->sa_family, 0));
 189 }
 190
 191 /*
 192  * if_simloop()
 193  *
 194  * This function is to support software emulation of hardware loopback,
 195  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 196  * hear their own broadcasts, we create a copy of the packet that we
 197  * would normally receive via a hardware loopback.
 198  *
 199  * This function expects the packet to include the media header of length hlen.
 200  */
 201 int
 202 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 203 {
 204         int isr;
 205
 206         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 207         m->m_pkthdr.rcvif = ifp;
 208
 209         /* BPF write needs to be handled specially */
 210         if (af == AF_UNSPEC) {
 211                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 212                 af = *(mtod(m, int *));
 213                 m->m_len -= sizeof(int);
 214                 m->m_pkthdr.len -= sizeof(int);
 215                 m->m_data += sizeof(int);
 216         }
 217
 218         if (ifp->if_bpf) {
 219                 bpf_gettoken();
 220
 221                 /* Re-check */
 222                 if (ifp->if_bpf == NULL)
 223                         goto rel;
 224
 225                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 226                         uint32_t bpf_af = (uint32_t)af;
 227                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 228                 } else {
 229                         bpf_mtap(ifp->if_bpf, m);
 230                 }
 231 rel:
 232                 bpf_reltoken();
 233         }
 234
 235         /* Strip away media header */
 236         if (hlen > 0)
 237                 m_adj(m, hlen);
 238
 239 #ifdef ALTQ
 240         /*
 241          * altq for loop is just for debugging.
 242          * only used when called for loop interface (not for
 243          * a simplex interface).
 244          */
 245         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 246                 struct altq_pktattr pktattr;
 247                 int32_t *afp;
 248
 249                 /*
 250                  * if the queueing discipline needs packet classification,
 251                  * do it before prepending link headers.
 252                  */
 253                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 254
 255                 M_PREPEND(m, sizeof(int32_t), M_NOWAIT);
 256                 if (m == NULL)
 257                         return(ENOBUFS);
 258                 afp = mtod(m, int32_t *);
 259                 *afp = (int32_t)af;
 260
 261                 return ifq_dispatch(ifp, m, &pktattr);
 262         }
 263 #endif /* ALTQ */
 264
 265         /* Deliver to upper layer protocol */
 266         switch (af) {
 267 #ifdef INET
 268         case AF_INET:
 269                 isr = NETISR_IP;
 270                 break;
 271 #endif
 272 #ifdef INET6
 273         case AF_INET6:
 274                 m->m_flags |= M_LOOP;
 275                 isr = NETISR_IPV6;
 276                 break;
 277 #endif
 278         default:
 279                 kprintf("if_simloop: can't handle af=%d\n", af);
 280                 m_freem(m);
 281                 return (EAFNOSUPPORT);
 282         }
 283
 284         IFNET_STAT_INC(ifp, ipackets, 1);
 285         IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 286         netisr_queue(isr, m);
 287         return (0);
 288 }
 289
 290 #ifdef ALTQ
 291 static void
 292 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq)
 293 {
 294         struct mbuf *m;
 295         int32_t af, *afp;
 296         int isr;
 297
 298         while (1) {
 299                 crit_enter();
 300                 m = ifsq_dequeue(ifsq);
 301                 crit_exit();
 302                 if (m == NULL)
 303                         return;
 304
 305                 afp = mtod(m, int32_t *);
 306                 af = *afp;
 307                 m_adj(m, sizeof(int32_t));
 308
 309                 switch (af) {
 310 #ifdef INET
 311                 case AF_INET:
 312                         isr = NETISR_IP;
 313                         break;
 314 #endif
 315 #ifdef INET6
 316                 case AF_INET6:
 317                         m->m_flags |= M_LOOP;
 318                         isr = NETISR_IPV6;
 319                         break;
 320 #endif
 321                 default:
 322                         kprintf("lo_altqstart: can't handle af%d\n", af);
 323                         m_freem(m);
 324                         return;
 325                 }
 326
 327                 IFNET_STAT_INC(ifp, ipackets, 1);
 328                 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 329                 netisr_queue(isr, m);
 330         }
 331 }
 332 #endif /* ALTQ */
 333
 334 /* ARGSUSED */
 335 static void
 336 lo_rtrequest(int cmd, struct rtentry *rt)
 337 {
 338         if (rt) {
 339                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 340                 /*
 341                  * For optimal performance, the send and receive buffers
 342                  * should be at least twice the MTU plus a little more for
 343                  * overhead.
 344                  */
 345                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 346         }
 347 }
 348
 349 /*
 350  * Process an ioctl request.
 351  */
 352 /* ARGSUSED */
 353 static int
 354 lo_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 355 {
 356         struct ifaddr *ifa;
 357         struct ifreq *ifr = (struct ifreq *)data;
 358         int error = 0, mask;
 359
 360         switch (cmd) {
 361         case SIOCSIFADDR:
 362                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 363                 ifa = (struct ifaddr *)data;
 364                 ifa->ifa_rtrequest = lo_rtrequest;
 365                 /*
 366                  * Everything else is done at a higher level.
 367                  */
 368                 break;
 369
 370         case SIOCADDMULTI:
 371         case SIOCDELMULTI:
 372                 if (ifr == NULL) {
 373                         error = EAFNOSUPPORT;           /* XXX */
 374                         break;
 375                 }
 376                 switch (ifr->ifr_addr.sa_family) {
 377
 378 #ifdef INET
 379                 case AF_INET:
 380                         break;
 381 #endif
 382 #ifdef INET6
 383                 case AF_INET6:
 384                         break;
 385 #endif
 386
 387                 default:
 388                         error = EAFNOSUPPORT;
 389                         break;
 390                 }
 391                 break;
 392
 393         case SIOCSIFMTU:
 394                 ifp->if_mtu = ifr->ifr_mtu;
 395                 break;
 396
 397         case SIOCSIFFLAGS:
 398                 break;
 399
 400         case SIOCSIFCAP:
 401                 mask = ifr->ifr_reqcap ^ ifp->if_capenable;
 402                 if (mask & IFCAP_HWCSUM) {
 403                         ifp->if_capenable ^= (mask & IFCAP_HWCSUM);
 404                         if (IFCAP_TXCSUM & ifp->if_capenable)
 405                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 406                         else
 407                                 ifp->if_hwassist = 0;
 408                 }
 409                 if (mask & IFCAP_RSS)
 410                         ifp->if_capenable ^= IFCAP_RSS;
 411                 break;
 412
 413         default:
 414                 error = EINVAL;
 415         }
 416         return (error);
 417 }