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      looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
  77                          struct rtentry *);
  78 static int      loioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
  79 static void     lortrequest(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 = loioctl;
 121         ifp->if_output = looutput;
 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         return (0);
 148 }
 149
 150 static int
 151 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 152          struct rtentry *rt)
 153 {
 154         M_ASSERTPKTHDR(m);
 155
 156         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 157                 m_freem(m);
 158                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 159                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 160         }
 161
 162         IFNET_STAT_INC(ifp, opackets, 1);
 163         IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len);
 164 #if 1   /* XXX */
 165         switch (dst->sa_family) {
 166         case AF_INET:
 167         case AF_INET6:
 168                 break;
 169         default:
 170                 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
 171                 m_freem(m);
 172                 return (EAFNOSUPPORT);
 173         }
 174 #endif
 175
 176         if (ifp->if_capenable & IFCAP_RXCSUM) {
 177                 int csum_flags = 0;
 178
 179                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 180                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 181                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 182                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 183
 184                 m->m_pkthdr.csum_flags |= csum_flags;
 185                 if (csum_flags & CSUM_DATA_VALID)
 186                         m->m_pkthdr.csum_data = 0xffff;
 187         }
 188         if ((ifp->if_capenable & IFCAP_RSS) == 0)
 189                 m->m_flags &= ~M_HASH;
 190         return (if_simloop(ifp, m, dst->sa_family, 0));
 191 }
 192
 193 /*
 194  * if_simloop()
 195  *
 196  * This function is to support software emulation of hardware loopback,
 197  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 198  * hear their own broadcasts, we create a copy of the packet that we
 199  * would normally receive via a hardware loopback.
 200  *
 201  * This function expects the packet to include the media header of length hlen.
 202  */
 203 int
 204 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 205 {
 206         int isr;
 207
 208         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 209         m->m_pkthdr.rcvif = ifp;
 210
 211         /* BPF write needs to be handled specially */
 212         if (af == AF_UNSPEC) {
 213                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 214                 af = *(mtod(m, int *));
 215                 m->m_len -= sizeof(int);
 216                 m->m_pkthdr.len -= sizeof(int);
 217                 m->m_data += sizeof(int);
 218         }
 219
 220         if (ifp->if_bpf) {
 221                 bpf_gettoken();
 222
 223                 /* Re-check */
 224                 if (ifp->if_bpf == NULL)
 225                         goto rel;
 226
 227                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 228                         uint32_t bpf_af = (uint32_t)af;
 229                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 230                 } else {
 231                         bpf_mtap(ifp->if_bpf, m);
 232                 }
 233 rel:
 234                 bpf_reltoken();
 235         }
 236
 237         /* Strip away media header */
 238         if (hlen > 0)
 239                 m_adj(m, hlen);
 240
 241 #ifdef ALTQ
 242         /*
 243          * altq for loop is just for debugging.
 244          * only used when called for loop interface (not for
 245          * a simplex interface).
 246          */
 247         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 248                 struct altq_pktattr pktattr;
 249                 int32_t *afp;
 250
 251                 /*
 252                  * if the queueing discipline needs packet classification,
 253                  * do it before prepending link headers.
 254                  */
 255                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 256
 257                 M_PREPEND(m, sizeof(int32_t), M_NOWAIT);
 258                 if (m == NULL)
 259                         return(ENOBUFS);
 260                 afp = mtod(m, int32_t *);
 261                 *afp = (int32_t)af;
 262
 263                 return ifq_dispatch(ifp, m, &pktattr);
 264         }
 265 #endif /* ALTQ */
 266
 267         /* Deliver to upper layer protocol */
 268         switch (af) {
 269 #ifdef INET
 270         case AF_INET:
 271                 isr = NETISR_IP;
 272                 break;
 273 #endif
 274 #ifdef INET6
 275         case AF_INET6:
 276                 m->m_flags |= M_LOOP;
 277                 isr = NETISR_IPV6;
 278                 break;
 279 #endif
 280         default:
 281                 kprintf("if_simloop: can't handle af=%d\n", af);
 282                 m_freem(m);
 283                 return (EAFNOSUPPORT);
 284         }
 285
 286         IFNET_STAT_INC(ifp, ipackets, 1);
 287         IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 288         netisr_queue(isr, m);
 289         return (0);
 290 }
 291
 292 #ifdef ALTQ
 293 static void
 294 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq)
 295 {
 296         struct mbuf *m;
 297         int32_t af, *afp;
 298         int isr;
 299
 300         while (1) {
 301                 crit_enter();
 302                 m = ifsq_dequeue(ifsq);
 303                 crit_exit();
 304                 if (m == NULL)
 305                         return;
 306
 307                 afp = mtod(m, int32_t *);
 308                 af = *afp;
 309                 m_adj(m, sizeof(int32_t));
 310
 311                 switch (af) {
 312 #ifdef INET
 313                 case AF_INET:
 314                         isr = NETISR_IP;
 315                         break;
 316 #endif
 317 #ifdef INET6
 318                 case AF_INET6:
 319                         m->m_flags |= M_LOOP;
 320                         isr = NETISR_IPV6;
 321                         break;
 322 #endif
 323                 default:
 324                         kprintf("lo_altqstart: can't handle af%d\n", af);
 325                         m_freem(m);
 326                         return;
 327                 }
 328
 329                 IFNET_STAT_INC(ifp, ipackets, 1);
 330                 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 331                 netisr_queue(isr, m);
 332         }
 333 }
 334 #endif /* ALTQ */
 335
 336 /* ARGSUSED */
 337 static void
 338 lortrequest(int cmd, struct rtentry *rt)
 339 {
 340         if (rt) {
 341                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 342                 /*
 343                  * For optimal performance, the send and receive buffers
 344                  * should be at least twice the MTU plus a little more for
 345                  * overhead.
 346                  */
 347                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 348         }
 349 }
 350
 351 /*
 352  * Process an ioctl request.
 353  */
 354 /* ARGSUSED */
 355 static int
 356 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 357 {
 358         struct ifaddr *ifa;
 359         struct ifreq *ifr = (struct ifreq *)data;
 360         int error = 0, mask;
 361
 362         switch (cmd) {
 363         case SIOCSIFADDR:
 364                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 365                 ifa = (struct ifaddr *)data;
 366                 ifa->ifa_rtrequest = lortrequest;
 367                 /*
 368                  * Everything else is done at a higher level.
 369                  */
 370                 break;
 371
 372         case SIOCADDMULTI:
 373         case SIOCDELMULTI:
 374                 if (ifr == NULL) {
 375                         error = EAFNOSUPPORT;           /* XXX */
 376                         break;
 377                 }
 378                 switch (ifr->ifr_addr.sa_family) {
 379
 380 #ifdef INET
 381                 case AF_INET:
 382                         break;
 383 #endif
 384 #ifdef INET6
 385                 case AF_INET6:
 386                         break;
 387 #endif
 388
 389                 default:
 390                         error = EAFNOSUPPORT;
 391                         break;
 392                 }
 393                 break;
 394
 395         case SIOCSIFMTU:
 396                 ifp->if_mtu = ifr->ifr_mtu;
 397                 break;
 398
 399         case SIOCSIFFLAGS:
 400                 break;
 401
 402         case SIOCSIFCAP:
 403                 mask = ifr->ifr_reqcap ^ ifp->if_capenable;
 404                 if (mask & IFCAP_HWCSUM) {
 405                         ifp->if_capenable ^= (mask & IFCAP_HWCSUM);
 406                         if (IFCAP_TXCSUM & ifp->if_capenable)
 407                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 408                         else
 409                                 ifp->if_hwassist = 0;
 410                 }
 411                 if (mask & IFCAP_RSS)
 412                         ifp->if_capenable ^= IFCAP_RSS;
 413                 break;
 414
 415         default:
 416                 error = EINVAL;
 417         }
 418         return (error);
 419 }