1 /* $NetBSD: if_loop.c,v 1.118 2022/09/04 23:34:51 thorpej Exp $ */ 2 3 /* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1982, 1986, 1993 34 * The Regents of the University of California. All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. Neither the name of the University nor the names of its contributors 45 * may be used to endorse or promote products derived from this software 46 * without specific prior written permission. 47 * 48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 58 * SUCH DAMAGE. 59 * 60 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95 61 */ 62 63 /* 64 * Loopback interface driver for protocol testing and timing. 65 */ 66 67 #include <sys/cdefs.h> 68 __KERNEL_RCSID(0, "$NetBSD: if_loop.c,v 1.118 2022/09/04 23:34:51 thorpej Exp $"); 69 70 #ifdef _KERNEL_OPT 71 #include "opt_inet.h" 72 #include "opt_atalk.h" 73 #include "opt_mbuftrace.h" 74 #include "opt_mpls.h" 75 #include "opt_net_mpsafe.h" 76 #endif 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/kernel.h> 81 #include <sys/mbuf.h> 82 #include <sys/socket.h> 83 #include <sys/errno.h> 84 #include <sys/ioctl.h> 85 #include <sys/time.h> 86 #include <sys/device.h> 87 #include <sys/module.h> 88 89 #include <sys/cpu.h> 90 91 #include <net/if.h> 92 #include <net/if_types.h> 93 #include <net/route.h> 94 95 #ifdef INET 96 #include <netinet/in.h> 97 #include <netinet/in_systm.h> 98 #include <netinet/in_var.h> 99 #include <netinet/in_offload.h> 100 #include <netinet/ip.h> 101 #include <netinet/ip_var.h> 102 #endif 103 104 #ifdef INET6 105 #ifndef INET 106 #include <netinet/in.h> 107 #endif 108 #include <netinet6/in6_var.h> 109 #include <netinet6/in6_offload.h> 110 #include <netinet/ip6.h> 111 #endif 112 113 #ifdef MPLS 114 #include <netmpls/mpls.h> 115 #include <netmpls/mpls_var.h> 116 #endif 117 118 #ifdef NETATALK 119 #include <netatalk/at.h> 120 #include <netatalk/at_var.h> 121 #endif 122 123 #include <net/bpf.h> 124 125 #if defined(LARGE_LOMTU) 126 #define LOMTU (131072 + MHLEN + MLEN) 127 #define LOMTU_MAX LOMTU 128 #else 129 #define LOMTU (32768 + MHLEN + MLEN) 130 #define LOMTU_MAX (65536 + MHLEN + MLEN) 131 #endif 132 133 #ifdef ALTQ 134 static void lostart(struct ifnet *); 135 #endif 136 137 static int loop_clone_create(struct if_clone *, int); 138 static int loop_clone_destroy(struct ifnet *); 139 140 static void loop_rtrequest(int, struct rtentry *, const struct rt_addrinfo *); 141 142 static struct if_clone loop_cloner = 143 IF_CLONE_INITIALIZER("lo", loop_clone_create, loop_clone_destroy); 144 145 void 146 loopattach(int n) 147 { 148 149 #ifndef _MODULE 150 loop_clone_create(&loop_cloner, 0); /* lo0 always exists */ 151 #endif 152 } 153 154 void 155 loopinit(void) 156 { 157 158 if (lo0ifp != NULL) /* can happen in rump kernel */ 159 return; 160 161 #ifdef _MODULE 162 loop_clone_create(&loop_cloner, 0); /* lo0 always exists */ 163 #endif 164 if_clone_attach(&loop_cloner); 165 } 166 167 static int 168 loopdetach(void) 169 { 170 /* no detach for now; we don't allow lo0 to be deleted */ 171 return EBUSY; 172 } 173 174 static int 175 loop_clone_create(struct if_clone *ifc, int unit) 176 { 177 struct ifnet *ifp; 178 179 ifp = if_alloc(IFT_LOOP); 180 181 if_initname(ifp, ifc->ifc_name, unit); 182 183 ifp->if_mtu = LOMTU; 184 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST; 185 #ifdef NET_MPSAFE 186 ifp->if_extflags = IFEF_MPSAFE; 187 #endif 188 ifp->if_ioctl = loioctl; 189 ifp->if_output = looutput; 190 #ifdef ALTQ 191 ifp->if_start = lostart; 192 #endif 193 ifp->if_type = IFT_LOOP; 194 ifp->if_hdrlen = 0; 195 ifp->if_addrlen = 0; 196 ifp->if_dlt = DLT_NULL; 197 IFQ_SET_READY(&ifp->if_snd); 198 if (unit == 0) 199 lo0ifp = ifp; 200 if_initialize(ifp); 201 ifp->if_link_state = LINK_STATE_UP; 202 if_alloc_sadl(ifp); 203 bpf_attach(ifp, DLT_NULL, sizeof(u_int)); 204 #ifdef MBUFTRACE 205 ifp->if_mowner = malloc(sizeof(struct mowner), M_DEVBUF, 206 M_WAITOK | M_ZERO); 207 strlcpy(ifp->if_mowner->mo_name, ifp->if_xname, 208 sizeof(ifp->if_mowner->mo_name)); 209 MOWNER_ATTACH(ifp->if_mowner); 210 #endif 211 212 ifp->if_flags |= IFF_RUNNING; 213 if_register(ifp); 214 215 return (0); 216 } 217 218 static int 219 loop_clone_destroy(struct ifnet *ifp) 220 { 221 222 if (ifp == lo0ifp) 223 return (EPERM); 224 225 ifp->if_flags &= ~IFF_RUNNING; 226 227 #ifdef MBUFTRACE 228 MOWNER_DETACH(ifp->if_mowner); 229 free(ifp->if_mowner, M_DEVBUF); 230 #endif 231 232 bpf_detach(ifp); 233 if_detach(ifp); 234 235 if_free(ifp); 236 237 return (0); 238 } 239 240 int 241 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, 242 const struct rtentry *rt) 243 { 244 pktqueue_t *pktq = NULL; 245 int s; 246 int csum_flags; 247 int error = 0; 248 size_t pktlen; 249 250 MCLAIM(m, ifp->if_mowner); 251 252 KERNEL_LOCK_UNLESS_NET_MPSAFE(); 253 254 if ((m->m_flags & M_PKTHDR) == 0) 255 panic("looutput: no header mbuf"); 256 if (ifp->if_flags & IFF_LOOPBACK) 257 bpf_mtap_af(ifp, dst->sa_family, m, BPF_D_OUT); 258 m_set_rcvif(m, ifp); 259 260 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 261 m_freem(m); 262 error = (rt->rt_flags & RTF_BLACKHOLE ? 0 : 263 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 264 goto out; 265 } 266 267 pktlen = m->m_pkthdr.len; 268 269 if_statadd2(ifp, if_opackets, 1, if_obytes, pktlen); 270 271 #ifdef ALTQ 272 /* 273 * ALTQ on the loopback interface is just for debugging. It's 274 * used only for loopback interfaces, not for a simplex interface. 275 */ 276 if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) && 277 ifp->if_start == lostart) { 278 /* 279 * If the queueing discipline needs packet classification, 280 * do it before prepending the link headers. 281 */ 282 IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family); 283 284 M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT); 285 if (m == NULL) { 286 if_statinc(ifp, if_oerrors); 287 error = ENOBUFS; 288 goto out; 289 } 290 *(mtod(m, uint32_t *)) = dst->sa_family; 291 292 error = if_transmit_lock(ifp, m); 293 goto out; 294 } 295 #endif /* ALTQ */ 296 297 m_tag_delete_chain(m); 298 299 #ifdef MPLS 300 bool is_mpls = false; 301 if (rt != NULL && rt_gettag(rt) != NULL && 302 rt_gettag(rt)->sa_family == AF_MPLS && 303 (m->m_flags & (M_MCAST | M_BCAST)) == 0) { 304 union mpls_shim msh; 305 msh.s_addr = MPLS_GETSADDR(rt); 306 if (msh.shim.label != MPLS_LABEL_IMPLNULL) { 307 is_mpls = true; 308 pktq = mpls_pktq; 309 } 310 } 311 if (!is_mpls) 312 #endif 313 switch (dst->sa_family) { 314 315 #ifdef INET 316 case AF_INET: 317 csum_flags = m->m_pkthdr.csum_flags; 318 KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0); 319 if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) { 320 in_undefer_cksum(m, 0, csum_flags); 321 m->m_pkthdr.csum_flags = 0; 322 } else { 323 /* 324 * Do nothing. Pass M_CSUM_IPv4 and M_CSUM_UDPv4 as 325 * they are to tell those are calculated and good. 326 */ 327 } 328 pktq = ip_pktq; 329 break; 330 #endif 331 #ifdef INET6 332 case AF_INET6: 333 csum_flags = m->m_pkthdr.csum_flags; 334 KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0); 335 if (csum_flags != 0 && 336 IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) { 337 in6_undefer_cksum(m, 0, csum_flags); 338 m->m_pkthdr.csum_flags = 0; 339 } else { 340 /* 341 * Do nothing. Pass M_CSUM_UDPv6 as 342 * they are to tell those are calculated and good. 343 */ 344 } 345 m->m_flags |= M_LOOP; 346 pktq = ip6_pktq; 347 break; 348 #endif 349 #ifdef NETATALK 350 case AF_APPLETALK: 351 pktq = at_pktq2; 352 break; 353 #endif 354 default: 355 printf("%s: can't handle af%d\n", ifp->if_xname, 356 dst->sa_family); 357 m_freem(m); 358 error = EAFNOSUPPORT; 359 goto out; 360 } 361 362 KASSERT(pktq != NULL); 363 364 error = 0; 365 s = splnet(); 366 if (__predict_true(pktq_enqueue(pktq, m, 0))) { 367 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen); 368 } else { 369 m_freem(m); 370 if_statinc(ifp, if_oerrors); 371 error = ENOBUFS; 372 } 373 splx(s); 374 out: 375 KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 376 return error; 377 } 378 379 #ifdef ALTQ 380 static void 381 lostart(struct ifnet *ifp) 382 { 383 for (;;) { 384 pktqueue_t *pktq = NULL; 385 struct mbuf *m; 386 size_t pktlen; 387 uint32_t af; 388 int s; 389 390 IFQ_DEQUEUE(&ifp->if_snd, m); 391 if (m == NULL) 392 return; 393 394 af = *(mtod(m, uint32_t *)); 395 m_adj(m, sizeof(uint32_t)); 396 397 switch (af) { 398 #ifdef INET 399 case AF_INET: 400 pktq = ip_pktq; 401 break; 402 #endif 403 #ifdef INET6 404 case AF_INET6: 405 m->m_flags |= M_LOOP; 406 pktq = ip6_pktq; 407 break; 408 #endif 409 #ifdef NETATALK 410 case AF_APPLETALK: 411 pktq = at_pktq2; 412 break; 413 #endif 414 default: 415 printf("%s: can't handle af%d\n", ifp->if_xname, af); 416 m_freem(m); 417 return; 418 } 419 pktlen = m->m_pkthdr.len; 420 421 KASSERT(pktq != NULL); 422 423 s = splnet(); 424 if (__predict_false(pktq_enqueue(pktq, m, 0))) { 425 m_freem(m); 426 splx(s); 427 return; 428 } 429 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen); 430 splx(s); 431 } 432 } 433 #endif /* ALTQ */ 434 435 /* ARGSUSED */ 436 static void 437 loop_rtrequest(int cmd, struct rtentry *rt, 438 const struct rt_addrinfo *info) 439 { 440 441 if (rt) 442 rt->rt_rmx.rmx_mtu = lo0ifp->if_mtu; 443 } 444 445 /* 446 * Process an ioctl request. 447 */ 448 /* ARGSUSED */ 449 int 450 loioctl(struct ifnet *ifp, u_long cmd, void *data) 451 { 452 struct ifaddr *ifa; 453 struct ifreq *ifr = data; 454 int error = 0; 455 456 switch (cmd) { 457 458 case SIOCINITIFADDR: 459 ifp->if_flags |= IFF_UP; 460 ifa = (struct ifaddr *)data; 461 if (ifa != NULL) 462 ifa->ifa_rtrequest = loop_rtrequest; 463 /* 464 * Everything else is done at a higher level. 465 */ 466 break; 467 468 case SIOCSIFMTU: 469 if ((unsigned)ifr->ifr_mtu > LOMTU_MAX) 470 error = EINVAL; 471 else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET){ 472 error = 0; 473 } 474 break; 475 476 case SIOCADDMULTI: 477 case SIOCDELMULTI: 478 if (ifr == NULL) { 479 error = EAFNOSUPPORT; /* XXX */ 480 break; 481 } 482 switch (ifreq_getaddr(cmd, ifr)->sa_family) { 483 484 #ifdef INET 485 case AF_INET: 486 break; 487 #endif 488 #ifdef INET6 489 case AF_INET6: 490 break; 491 #endif 492 493 default: 494 error = EAFNOSUPPORT; 495 break; 496 } 497 break; 498 499 default: 500 error = ifioctl_common(ifp, cmd, data); 501 } 502 return (error); 503 } 504 505 /* 506 * Module infrastructure 507 */ 508 #include "if_module.h" 509 510 IF_MODULE(MODULE_CLASS_DRIVER, loop, NULL) 511
Indexes created Sat Sep 20 22:09:52 GMT 2025