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