1 /* $NetBSD: if_loop.c,v 1.113 2021/06/16 00:21:19 riastradh 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 1.113 2021/06/16 00:21:19 riastradh 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/netisr.h> 94 #include <net/route.h> 95 96 #ifdef INET 97 #include <netinet/in.h> 98 #include <netinet/in_systm.h> 99 #include <netinet/in_var.h> 100 #include <netinet/in_offload.h> 101 #include <netinet/ip.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 struct ifqueue *ifq = NULL; 246 int s, isr = -1; 247 int csum_flags; 248 int error = 0; 249 size_t pktlen; 250 251 MCLAIM(m, ifp->if_mowner); 252 253 KERNEL_LOCK_UNLESS_NET_MPSAFE(); 254 255 if ((m->m_flags & M_PKTHDR) == 0) 256 panic("looutput: no header mbuf"); 257 if (ifp->if_flags & IFF_LOOPBACK) 258 bpf_mtap_af(ifp, dst->sa_family, m, BPF_D_OUT); 259 m_set_rcvif(m, ifp); 260 261 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) { 262 m_freem(m); 263 error = (rt->rt_flags & RTF_BLACKHOLE ? 0 : 264 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 265 goto out; 266 } 267 268 pktlen = m->m_pkthdr.len; 269 270 if_statadd2(ifp, if_opackets, 1, if_obytes, pktlen); 271 272 #ifdef ALTQ 273 /* 274 * ALTQ on the loopback interface is just for debugging. It's 275 * used only for loopback interfaces, not for a simplex interface. 276 */ 277 if ((ALTQ_IS_ENABLED(&ifp->if_snd) || TBR_IS_ENABLED(&ifp->if_snd)) && 278 ifp->if_start == lostart) { 279 /* 280 * If the queueing discipline needs packet classification, 281 * do it before prepending the link headers. 282 */ 283 IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family); 284 285 M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT); 286 if (m == NULL) { 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 if (rt != NULL && rt_gettag(rt) != NULL && 301 rt_gettag(rt)->sa_family == AF_MPLS && 302 (m->m_flags & (M_MCAST | M_BCAST)) == 0) { 303 union mpls_shim msh; 304 msh.s_addr = MPLS_GETSADDR(rt); 305 if (msh.shim.label != MPLS_LABEL_IMPLNULL) { 306 ifq = &mplsintrq; 307 isr = NETISR_MPLS; 308 } 309 } 310 if (isr != NETISR_MPLS) 311 #endif 312 switch (dst->sa_family) { 313 314 #ifdef INET 315 case AF_INET: 316 csum_flags = m->m_pkthdr.csum_flags; 317 KASSERT((csum_flags & ~(M_CSUM_IPv4|M_CSUM_UDPv4)) == 0); 318 if (csum_flags != 0 && IN_LOOPBACK_NEED_CHECKSUM(csum_flags)) { 319 in_undefer_cksum(m, 0, csum_flags); 320 m->m_pkthdr.csum_flags = 0; 321 } else { 322 /* 323 * Do nothing. Pass M_CSUM_IPv4 and M_CSUM_UDPv4 as 324 * they are to tell those are calculated and good. 325 */ 326 } 327 pktq = ip_pktq; 328 break; 329 #endif 330 #ifdef INET6 331 case AF_INET6: 332 csum_flags = m->m_pkthdr.csum_flags; 333 KASSERT((csum_flags & ~M_CSUM_UDPv6) == 0); 334 if (csum_flags != 0 && 335 IN6_LOOPBACK_NEED_CHECKSUM(csum_flags)) { 336 in6_undefer_cksum(m, 0, csum_flags); 337 m->m_pkthdr.csum_flags = 0; 338 } else { 339 /* 340 * Do nothing. Pass M_CSUM_UDPv6 as 341 * they are to tell those are calculated and good. 342 */ 343 } 344 m->m_flags |= M_LOOP; 345 pktq = ip6_pktq; 346 break; 347 #endif 348 #ifdef NETATALK 349 case AF_APPLETALK: 350 ifq = &atintrq2; 351 isr = NETISR_ATALK; 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 s = splnet(); 363 if (__predict_true(pktq)) { 364 error = 0; 365 366 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 error = ENOBUFS; 371 } 372 splx(s); 373 goto out; 374 } 375 if (IF_QFULL(ifq)) { 376 IF_DROP(ifq); 377 m_freem(m); 378 splx(s); 379 error = ENOBUFS; 380 goto out; 381 } 382 if_statadd2(ifp, if_ipackets, 1, if_ibytes, m->m_pkthdr.len); 383 IF_ENQUEUE(ifq, m); 384 schednetisr(isr); 385 splx(s); 386 out: 387 KERNEL_UNLOCK_UNLESS_NET_MPSAFE(); 388 return error; 389 } 390 391 #ifdef ALTQ 392 static void 393 lostart(struct ifnet *ifp) 394 { 395 for (;;) { 396 pktqueue_t *pktq = NULL; 397 struct ifqueue *ifq = NULL; 398 struct mbuf *m; 399 size_t pktlen; 400 uint32_t af; 401 int s, isr = 0; 402 403 IFQ_DEQUEUE(&ifp->if_snd, m); 404 if (m == NULL) 405 return; 406 407 af = *(mtod(m, uint32_t *)); 408 m_adj(m, sizeof(uint32_t)); 409 410 switch (af) { 411 #ifdef INET 412 case AF_INET: 413 pktq = ip_pktq; 414 break; 415 #endif 416 #ifdef INET6 417 case AF_INET6: 418 m->m_flags |= M_LOOP; 419 pktq = ip6_pktq; 420 break; 421 #endif 422 #ifdef NETATALK 423 case AF_APPLETALK: 424 ifq = &atintrq2; 425 isr = NETISR_ATALK; 426 break; 427 #endif 428 default: 429 printf("%s: can't handle af%d\n", ifp->if_xname, af); 430 m_freem(m); 431 return; 432 } 433 pktlen = m->m_pkthdr.len; 434 435 s = splnet(); 436 if (__predict_true(pktq)) { 437 if (__predict_false(pktq_enqueue(pktq, m, 0))) { 438 m_freem(m); 439 splx(s); 440 return; 441 } 442 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen); 443 splx(s); 444 continue; 445 } 446 if (IF_QFULL(ifq)) { 447 IF_DROP(ifq); 448 splx(s); 449 m_freem(m); 450 return; 451 } 452 IF_ENQUEUE(ifq, m); 453 schednetisr(isr); 454 if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen); 455 splx(s); 456 } 457 } 458 #endif /* ALTQ */ 459 460 /* ARGSUSED */ 461 static void 462 loop_rtrequest(int cmd, struct rtentry *rt, 463 const struct rt_addrinfo *info) 464 { 465 466 if (rt) 467 rt->rt_rmx.rmx_mtu = lo0ifp->if_mtu; 468 } 469 470 /* 471 * Process an ioctl request. 472 */ 473 /* ARGSUSED */ 474 int 475 loioctl(struct ifnet *ifp, u_long cmd, void *data) 476 { 477 struct ifaddr *ifa; 478 struct ifreq *ifr = data; 479 int error = 0; 480 481 switch (cmd) { 482 483 case SIOCINITIFADDR: 484 ifp->if_flags |= IFF_UP; 485 ifa = (struct ifaddr *)data; 486 if (ifa != NULL) 487 ifa->ifa_rtrequest = loop_rtrequest; 488 /* 489 * Everything else is done at a higher level. 490 */ 491 break; 492 493 case SIOCSIFMTU: 494 if ((unsigned)ifr->ifr_mtu > LOMTU_MAX) 495 error = EINVAL; 496 else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET){ 497 error = 0; 498 } 499 break; 500 501 case SIOCADDMULTI: 502 case SIOCDELMULTI: 503 if (ifr == NULL) { 504 error = EAFNOSUPPORT; /* XXX */ 505 break; 506 } 507 switch (ifreq_getaddr(cmd, ifr)->sa_family) { 508 509 #ifdef INET 510 case AF_INET: 511 break; 512 #endif 513 #ifdef INET6 514 case AF_INET6: 515 break; 516 #endif 517 518 default: 519 error = EAFNOSUPPORT; 520 break; 521 } 522 break; 523 524 default: 525 error = ifioctl_common(ifp, cmd, data); 526 } 527 return (error); 528 } 529 530 /* 531 * Module infrastructure 532 */ 533 #include "if_module.h" 534 535 IF_MODULE(MODULE_CLASS_DRIVER, loop, NULL) 536