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 #ifdef 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
 103         if_clone_attach(&lo_cloner);
 104 }
 105 SYSINIT(lo_sysinit, SI_SUB_PSEUDO, SI_ORDER_ANY, lo_sysinit, NULL);
 106
 107 static int
 108 lo_clone_create(struct if_clone *ifc __unused, int unit, caddr_t param __unused)
 109 {
 110         struct ifnet *ifp;
 111
 112         ifp = kmalloc(sizeof(*ifp), M_IFNET, M_WAITOK | M_ZERO);
 113
 114         if_initname(ifp, "lo", unit);
 115         ifp->if_mtu = LOMTU;
 116         ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 117         ifp->if_capabilities = IFCAP_HWCSUM | IFCAP_RSS;
 118         ifp->if_hwassist = LO_CSUM_FEATURES;
 119         ifp->if_capenable = ifp->if_capabilities;
 120         ifp->if_ioctl = lo_ioctl;
 121         ifp->if_output = lo_output;
 122         ifp->if_type = IFT_LOOP;
 123         ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 124         ifq_set_ready(&ifp->if_snd);
 125 #ifdef ALTQ
 126         ifp->if_start = lo_altqstart;
 127 #endif
 128         if_attach(ifp, NULL);
 129         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 130
 131         if (loif == NULL) {
 132                 KASSERT(unit == 0, ("loif is %s", ifp->if_xname));
 133                 loif = ifp;
 134         }
 135         return (0);
 136 }
 137
 138 static int
 139 lo_clone_destroy(struct ifnet *ifp)
 140 {
 141
 142         if (loif == ifp)
 143                 return (EPERM);
 144
 145         bpfdetach(ifp);
 146         if_detach(ifp);
 147         kfree(ifp, M_IFNET);
 148         return (0);
 149 }
 150
 151 static int
 152 lo_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 153     struct rtentry *rt)
 154 {
 155         M_ASSERTPKTHDR(m);
 156
 157         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 158                 m_freem(m);
 159                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 160                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 161         }
 162
 163         IFNET_STAT_INC(ifp, opackets, 1);
 164         IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len);
 165 #if 1   /* XXX */
 166         switch (dst->sa_family) {
 167         case AF_INET:
 168         case AF_INET6:
 169                 break;
 170         default:
 171                 kprintf("lo_output: af=%d unexpected\n", dst->sa_family);
 172                 m_freem(m);
 173                 return (EAFNOSUPPORT);
 174         }
 175 #endif
 176
 177         if (ifp->if_capenable & IFCAP_RXCSUM) {
 178                 int csum_flags = 0;
 179
 180                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 181                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 182                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 183                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 184
 185                 m->m_pkthdr.csum_flags |= csum_flags;
 186                 if (csum_flags & CSUM_DATA_VALID)
 187                         m->m_pkthdr.csum_data = 0xffff;
 188         }
 189         if ((ifp->if_capenable & IFCAP_RSS) == 0)
 190                 m->m_flags &= ~M_HASH;
 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                 bpf_gettoken();
 223
 224                 /* Re-check */
 225                 if (ifp->if_bpf == NULL)
 226                         goto rel;
 227
 228                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 229                         uint32_t bpf_af = (uint32_t)af;
 230                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 231                 } else {
 232                         bpf_mtap(ifp->if_bpf, m);
 233                 }
 234 rel:
 235                 bpf_reltoken();
 236         }
 237
 238         /* Strip away media header */
 239         if (hlen > 0)
 240                 m_adj(m, hlen);
 241
 242 #ifdef ALTQ
 243         /*
 244          * altq for loop is just for debugging.
 245          * only used when called for loop interface (not for
 246          * a simplex interface).
 247          */
 248         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 249                 struct altq_pktattr pktattr;
 250                 int32_t *afp;
 251
 252                 /*
 253                  * if the queueing discipline needs packet classification,
 254                  * do it before prepending link headers.
 255                  */
 256                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 257
 258                 M_PREPEND(m, sizeof(int32_t), M_NOWAIT);
 259                 if (m == NULL)
 260                         return(ENOBUFS);
 261                 afp = mtod(m, int32_t *);
 262                 *afp = (int32_t)af;
 263
 264                 return ifq_dispatch(ifp, m, &pktattr);
 265         }
 266 #endif /* ALTQ */
 267
 268         /* Deliver to upper layer protocol */
 269         switch (af) {
 270 #ifdef INET
 271         case AF_INET:
 272                 isr = NETISR_IP;
 273                 break;
 274 #endif
 275 #ifdef INET6
 276         case AF_INET6:
 277                 m->m_flags |= M_LOOP;
 278                 isr = NETISR_IPV6;
 279                 break;
 280 #endif
 281         default:
 282                 kprintf("if_simloop: can't handle af=%d\n", af);
 283                 m_freem(m);
 284                 return (EAFNOSUPPORT);
 285         }
 286
 287         IFNET_STAT_INC(ifp, ipackets, 1);
 288         IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 289         netisr_queue(isr, m);
 290         return (0);
 291 }
 292
 293 #ifdef ALTQ
 294 static void
 295 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq)
 296 {
 297         struct mbuf *m;
 298         int32_t af, *afp;
 299         int isr;
 300
 301         while (1) {
 302                 crit_enter();
 303                 m = ifsq_dequeue(ifsq);
 304                 crit_exit();
 305                 if (m == NULL)
 306                         return;
 307
 308                 afp = mtod(m, int32_t *);
 309                 af = *afp;
 310                 m_adj(m, sizeof(int32_t));
 311
 312                 switch (af) {
 313 #ifdef INET
 314                 case AF_INET:
 315                         isr = NETISR_IP;
 316                         break;
 317 #endif
 318 #ifdef INET6
 319                 case AF_INET6:
 320                         m->m_flags |= M_LOOP;
 321                         isr = NETISR_IPV6;
 322                         break;
 323 #endif
 324                 default:
 325                         kprintf("lo_altqstart: can't handle af%d\n", af);
 326                         m_freem(m);
 327                         return;
 328                 }
 329
 330                 IFNET_STAT_INC(ifp, ipackets, 1);
 331                 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 332                 netisr_queue(isr, m);
 333         }
 334 }
 335 #endif /* ALTQ */
 336
 337 /* ARGSUSED */
 338 static void
 339 lo_rtrequest(int cmd, struct rtentry *rt)
 340 {
 341         if (rt) {
 342                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 343                 /*
 344                  * For optimal performance, the send and receive buffers
 345                  * should be at least twice the MTU plus a little more for
 346                  * overhead.
 347                  */
 348                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 349         }
 350 }
 351
 352 /*
 353  * Process an ioctl request.
 354  */
 355 /* ARGSUSED */
 356 static int
 357 lo_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 358 {
 359         struct ifaddr *ifa;
 360         struct ifreq *ifr = (struct ifreq *)data;
 361         int error = 0, mask;
 362
 363         switch (cmd) {
 364         case SIOCSIFADDR:
 365                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 366                 ifa = (struct ifaddr *)data;
 367                 ifa->ifa_rtrequest = lo_rtrequest;
 368                 /*
 369                  * Everything else is done at a higher level.
 370                  */
 371                 break;
 372
 373         case SIOCADDMULTI:
 374         case SIOCDELMULTI:
 375                 if (ifr == NULL) {
 376                         error = EAFNOSUPPORT;           /* XXX */
 377                         break;
 378                 }
 379                 switch (ifr->ifr_addr.sa_family) {
 380
 381 #ifdef INET
 382                 case AF_INET:
 383                         break;
 384 #endif
 385 #ifdef INET6
 386                 case AF_INET6:
 387                         break;
 388 #endif
 389
 390                 default:
 391                         error = EAFNOSUPPORT;
 392                         break;
 393                 }
 394                 break;
 395
 396         case SIOCSIFMTU:
 397                 ifp->if_mtu = ifr->ifr_mtu;
 398                 break;
 399
 400         case SIOCSIFFLAGS:
 401                 break;
 402
 403         case SIOCSIFCAP:
 404                 mask = ifr->ifr_reqcap ^ ifp->if_capenable;
 405                 if (mask & IFCAP_HWCSUM) {
 406                         ifp->if_capenable ^= (mask & IFCAP_HWCSUM);
 407                         if (IFCAP_TXCSUM & ifp->if_capenable)
 408                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 409                         else
 410                                 ifp->if_hwassist = 0;
 411                 }
 412                 if (mask & IFCAP_RSS)
 413                         ifp->if_capenable ^= IFCAP_RSS;
 414                 break;
 415
 416         default:
 417                 error = EINVAL;
 418         }
 419         return (error);
 420 }