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/ifq_var.h>
  54 #include <net/netisr.h>
  55 #include <net/route.h>
  56 #include <net/bpf.h>
  57 #include <net/bpfdesc.h>
  58
  59 #ifdef  INET
  60 #include <netinet/in.h>
  61 #include <netinet/in_var.h>
  62 #endif
  63
  64 #ifdef INET6
  65 #ifndef INET
  66 #include <netinet/in.h>
  67 #endif
  68 #include <netinet6/in6_var.h>
  69 #include <netinet/ip6.h>
  70 #endif
  71
  72 static void     loopattach(void *);
  73 static int      looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
  74                          struct rtentry *);
  75 static int      loioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
  76 static void     lortrequest(int, struct rtentry *);
  77 #ifdef ALTQ
  78 static void     lo_altqstart(struct ifnet *, struct ifaltq_subque *);
  79 #endif
  80 PSEUDO_SET(loopattach, if_loop);
  81
  82 #ifdef TINY_LOMTU
  83 #define LOMTU   (1024+512)
  84 #elif defined(LARGE_LOMTU)
  85 #define LOMTU   131072
  86 #else
  87 #define LOMTU   16384
  88 #endif
  89
  90 #define LO_CSUM_FEATURES        (CSUM_IP | CSUM_UDP | CSUM_TCP)
  91
  92 struct  ifnet loif[NLOOP];
  93
  94 /* ARGSUSED */
  95 static void
  96 loopattach(void *dummy)
  97 {
  98         struct ifnet *ifp;
  99         int i;
 100
 101         for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) {
 102                 if_initname(ifp, "lo", i);
 103                 ifp->if_mtu = LOMTU;
 104                 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
 105                 ifp->if_capabilities = IFCAP_HWCSUM;
 106                 ifp->if_hwassist = LO_CSUM_FEATURES;
 107                 ifp->if_capenable = ifp->if_capabilities;
 108                 ifp->if_ioctl = loioctl;
 109                 ifp->if_output = looutput;
 110                 ifp->if_type = IFT_LOOP;
 111                 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
 112                 ifq_set_ready(&ifp->if_snd);
 113 #ifdef ALTQ
 114                 ifp->if_start = lo_altqstart;
 115 #endif
 116                 if_attach(ifp, NULL);
 117                 bpfattach(ifp, DLT_NULL, sizeof(u_int));
 118         }
 119 }
 120
 121 static int
 122 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 123          struct rtentry *rt)
 124 {
 125         M_ASSERTPKTHDR(m);
 126
 127         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
 128                 m_freem(m);
 129                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
 130                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
 131         }
 132
 133         IFNET_STAT_INC(ifp, opackets, 1);
 134         IFNET_STAT_INC(ifp, obytes, m->m_pkthdr.len);
 135 #if 1   /* XXX */
 136         switch (dst->sa_family) {
 137         case AF_INET:
 138         case AF_INET6:
 139                 break;
 140         default:
 141                 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
 142                 m_freem(m);
 143                 return (EAFNOSUPPORT);
 144         }
 145 #endif
 146
 147         if (ifp->if_capenable & IFCAP_RXCSUM) {
 148                 int csum_flags = 0;
 149
 150                 if (m->m_pkthdr.csum_flags & CSUM_IP)
 151                         csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
 152                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
 153                         csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
 154
 155                 m->m_pkthdr.csum_flags |= csum_flags;
 156                 if (csum_flags & CSUM_DATA_VALID)
 157                         m->m_pkthdr.csum_data = 0xffff;
 158         }
 159         return (if_simloop(ifp, m, dst->sa_family, 0));
 160 }
 161
 162 /*
 163  * if_simloop()
 164  *
 165  * This function is to support software emulation of hardware loopback,
 166  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
 167  * hear their own broadcasts, we create a copy of the packet that we
 168  * would normally receive via a hardware loopback.
 169  *
 170  * This function expects the packet to include the media header of length hlen.
 171  */
 172 int
 173 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
 174 {
 175         int isr;
 176
 177         KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
 178         m->m_pkthdr.rcvif = ifp;
 179
 180         /* BPF write needs to be handled specially */
 181         if (af == AF_UNSPEC) {
 182                 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
 183                 af = *(mtod(m, int *));
 184                 m->m_len -= sizeof(int);
 185                 m->m_pkthdr.len -= sizeof(int);
 186                 m->m_data += sizeof(int);
 187         }
 188
 189         if (ifp->if_bpf) {
 190                 bpf_gettoken();
 191
 192                 /* Re-check */
 193                 if (ifp->if_bpf == NULL)
 194                         goto rel;
 195
 196                 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
 197                         uint32_t bpf_af = (uint32_t)af;
 198                         bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
 199                 } else {
 200                         bpf_mtap(ifp->if_bpf, m);
 201                 }
 202 rel:
 203                 bpf_reltoken();
 204         }
 205
 206         /* Strip away media header */
 207         if (hlen > 0)
 208                 m_adj(m, hlen);
 209
 210 #ifdef ALTQ
 211         /*
 212          * altq for loop is just for debugging.
 213          * only used when called for loop interface (not for
 214          * a simplex interface).
 215          */
 216         if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
 217                 struct altq_pktattr pktattr;
 218                 int32_t *afp;
 219
 220                 /*
 221                  * if the queueing discipline needs packet classification,
 222                  * do it before prepending link headers.
 223                  */
 224                 ifq_classify(&ifp->if_snd, m, af, &pktattr);
 225
 226                 M_PREPEND(m, sizeof(int32_t), M_NOWAIT);
 227                 if (m == NULL)
 228                         return(ENOBUFS);
 229                 afp = mtod(m, int32_t *);
 230                 *afp = (int32_t)af;
 231
 232                 return ifq_dispatch(ifp, m, &pktattr);
 233         }
 234 #endif /* ALTQ */
 235
 236         /* Deliver to upper layer protocol */
 237         switch (af) {
 238 #ifdef INET
 239         case AF_INET:
 240                 isr = NETISR_IP;
 241                 break;
 242 #endif
 243 #ifdef INET6
 244         case AF_INET6:
 245                 m->m_flags |= M_LOOP;
 246                 isr = NETISR_IPV6;
 247                 break;
 248 #endif
 249         default:
 250                 kprintf("if_simloop: can't handle af=%d\n", af);
 251                 m_freem(m);
 252                 return (EAFNOSUPPORT);
 253         }
 254
 255         IFNET_STAT_INC(ifp, ipackets, 1);
 256         IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 257         netisr_queue(isr, m);
 258         return (0);
 259 }
 260
 261 #ifdef ALTQ
 262 static void
 263 lo_altqstart(struct ifnet *ifp, struct ifaltq_subque *ifsq)
 264 {
 265         struct mbuf *m;
 266         int32_t af, *afp;
 267         int isr;
 268
 269         while (1) {
 270                 crit_enter();
 271                 m = ifsq_dequeue(ifsq);
 272                 crit_exit();
 273                 if (m == NULL)
 274                         return;
 275
 276                 afp = mtod(m, int32_t *);
 277                 af = *afp;
 278                 m_adj(m, sizeof(int32_t));
 279
 280                 switch (af) {
 281 #ifdef INET
 282                 case AF_INET:
 283                         isr = NETISR_IP;
 284                         break;
 285 #endif
 286 #ifdef INET6
 287                 case AF_INET6:
 288                         m->m_flags |= M_LOOP;
 289                         isr = NETISR_IPV6;
 290                         break;
 291 #endif
 292                 default:
 293                         kprintf("lo_altqstart: can't handle af%d\n", af);
 294                         m_freem(m);
 295                         return;
 296                 }
 297
 298                 IFNET_STAT_INC(ifp, ipackets, 1);
 299                 IFNET_STAT_INC(ifp, ibytes, m->m_pkthdr.len);
 300                 netisr_queue(isr, m);
 301         }
 302 }
 303 #endif /* ALTQ */
 304
 305 /* ARGSUSED */
 306 static void
 307 lortrequest(int cmd, struct rtentry *rt)
 308 {
 309         if (rt) {
 310                 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
 311                 /*
 312                  * For optimal performance, the send and receive buffers
 313                  * should be at least twice the MTU plus a little more for
 314                  * overhead.
 315                  */
 316                 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
 317         }
 318 }
 319
 320 /*
 321  * Process an ioctl request.
 322  */
 323 /* ARGSUSED */
 324 static int
 325 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
 326 {
 327         struct ifaddr *ifa;
 328         struct ifreq *ifr = (struct ifreq *)data;
 329         int error = 0, mask;
 330
 331         switch (cmd) {
 332         case SIOCSIFADDR:
 333                 ifp->if_flags |= IFF_UP | IFF_RUNNING;
 334                 ifa = (struct ifaddr *)data;
 335                 ifa->ifa_rtrequest = lortrequest;
 336                 /*
 337                  * Everything else is done at a higher level.
 338                  */
 339                 break;
 340
 341         case SIOCADDMULTI:
 342         case SIOCDELMULTI:
 343                 if (ifr == NULL) {
 344                         error = EAFNOSUPPORT;           /* XXX */
 345                         break;
 346                 }
 347                 switch (ifr->ifr_addr.sa_family) {
 348
 349 #ifdef INET
 350                 case AF_INET:
 351                         break;
 352 #endif
 353 #ifdef INET6
 354                 case AF_INET6:
 355                         break;
 356 #endif
 357
 358                 default:
 359                         error = EAFNOSUPPORT;
 360                         break;
 361                 }
 362                 break;
 363
 364         case SIOCSIFMTU:
 365                 ifp->if_mtu = ifr->ifr_mtu;
 366                 break;
 367
 368         case SIOCSIFFLAGS:
 369                 break;
 370
 371         case SIOCSIFCAP:
 372                 mask = (ifr->ifr_reqcap ^ ifp->if_capenable) & IFCAP_HWCSUM;
 373                 if (mask) {
 374                         ifp->if_capenable ^= mask;
 375                         if (IFCAP_TXCSUM & ifp->if_capenable)
 376                                 ifp->if_hwassist = LO_CSUM_FEATURES;
 377                         else
 378                                 ifp->if_hwassist = 0;
 379                 }
 380                 break;
 381
 382         default:
 383                 error = EINVAL;
 384         }
 385         return (error);
 386 }