2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1982, 1986, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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 University 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.
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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
31 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
36 * Loopback interface driver for protocol testing and timing.
40 #include "opt_inet6.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
47 #include <sys/module.h>
48 #include <machine/bus.h>
50 #include <sys/socket.h>
51 #include <sys/sockio.h>
52 #include <sys/sysctl.h>
55 #include <net/if_var.h>
56 #include <net/if_clone.h>
57 #include <net/if_types.h>
58 #include <net/netisr.h>
59 #include <net/route.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
70 #include <netinet/in.h>
72 #include <netinet6/in6_var.h>
73 #include <netinet/ip6.h>
76 #include <security/mac/mac_framework.h>
79 #define LOMTU (1024+512)
80 #elif defined(LARGE_LOMTU)
86 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
87 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
88 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
90 CSUM_IP_CHECKED | CSUM_IP_VALID | \
93 static int loioctl(struct ifnet *, u_long, caddr_t);
94 static int looutput(struct ifnet *ifp, struct mbuf *m,
95 const struct sockaddr *dst, struct route *ro);
97 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
100 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
101 #define V_lo_cloner VNET(lo_cloner)
104 static struct if_clone *lo_cloner;
105 static const char loname[] = "lo";
108 lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
110 if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
114 /* XXX: destroying lo0 will lead to panics. */
115 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
126 lo_clone_create(struct if_clone *ifc, char *name, size_t len,
127 struct ifc_data *ifd, struct ifnet **ifpp)
131 ifp = if_alloc(IFT_LOOP);
135 if_initname(ifp, loname, ifd->unit);
137 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
138 ifp->if_ioctl = loioctl;
139 ifp->if_output = looutput;
140 ifp->if_snd.ifq_maxlen = ifqmaxlen;
141 ifp->if_capabilities = ifp->if_capenable =
142 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
143 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
145 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
154 vnet_loif_init(const void *unused __unused)
156 struct if_clone_addreq req = {
157 .create_f = lo_clone_create,
158 .destroy_f = lo_clone_destroy,
159 .flags = IFC_F_AUTOUNIT,
161 lo_cloner = ifc_attach_cloner(loname, &req);
163 V_lo_cloner = lo_cloner;
165 struct ifc_data ifd = { .unit = 0 };
166 ifc_create_ifp(loname, &ifd, NULL);
168 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
169 vnet_loif_init, NULL);
173 vnet_loif_uninit(const void *unused __unused)
176 ifc_detach_cloner(V_lo_cloner);
179 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
180 vnet_loif_uninit, NULL);
184 loop_modevent(module_t mod, int type, void *data)
192 printf("loop module unload - not possible for this module type\n");
201 static moduledata_t loop_mod = {
207 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
210 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
218 M_ASSERTPKTHDR(m); /* check if we have the packet header */
221 error = mac_ifnet_check_transmit(ifp, m);
228 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
230 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
233 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
234 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
240 /* BPF writes need to be handled specially. */
241 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
242 bcopy(dst->sa_data, &af, sizeof(af));
244 af = RO_GET_FAMILY(ro, dst);
249 if (ifp->if_capenable & IFCAP_RXCSUM) {
250 m->m_pkthdr.csum_data = 0xffff;
251 m->m_pkthdr.csum_flags = LO_CSUM_SET;
253 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
258 * XXX-BZ for now always claim the checksum is good despite
259 * any interface flags. This is a workaround for 9.1-R and
260 * a proper solution ought to be sought later.
262 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
263 m->m_pkthdr.csum_data = 0xffff;
264 m->m_pkthdr.csum_flags = LO_CSUM_SET;
267 m->m_pkthdr.csum_data = 0xffff;
268 m->m_pkthdr.csum_flags = LO_CSUM_SET;
270 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
273 printf("looutput: af=%d unexpected\n", af);
275 return (EAFNOSUPPORT);
278 return (if_simloop(ifp, m, af, 0));
284 * This function is to support software emulation of hardware loopback,
285 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
286 * hear their own broadcasts, we create a copy of the packet that we
287 * would normally receive via a hardware loopback.
289 * This function expects the packet to include the media header of length hlen.
292 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
297 m_tag_delete_nonpersistent(m);
298 m->m_pkthdr.rcvif = ifp;
301 mac_ifnet_create_mbuf(ifp, m);
305 * Let BPF see incoming packet in the following manner:
306 * - Emulated packet loopback for a simplex interface
307 * (net/if_ethersubr.c)
308 * -> passes it to ifp's BPF
309 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
310 * -> not passes it to any BPF
311 * - Normal packet loopback from myself to myself (net/if_loop.c)
312 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
315 if (bpf_peers_present(ifp->if_bpf)) {
316 bpf_mtap(ifp->if_bpf, m);
319 if (bpf_peers_present(V_loif->if_bpf)) {
320 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
321 /* XXX beware sizeof(af) != 4 */
325 * We need to prepend the address family.
327 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
332 /* Strip away media header */
335 #ifndef __NO_STRICT_ALIGNMENT
337 * Some archs do not like unaligned data, so
338 * we move data down in the first mbuf.
340 if (mtod(m, vm_offset_t) & 3) {
341 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
343 (char *)(mtod(m, vm_offset_t)
344 - (mtod(m, vm_offset_t) & 3)),
346 m->m_data -= (mtod(m,vm_offset_t) & 3);
351 /* Deliver to upper layer protocol */
360 m->m_flags |= M_LOOP;
365 printf("if_simloop: can't handle af=%d\n", af);
367 return (EAFNOSUPPORT);
369 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
370 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
371 netisr_queue(isr, m); /* mbuf is free'd on failure. */
376 * Process an ioctl request.
379 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
381 struct ifreq *ifr = (struct ifreq *)data;
386 ifp->if_flags |= IFF_UP;
387 ifp->if_drv_flags |= IFF_DRV_RUNNING;
388 if_link_state_change(ifp, LINK_STATE_UP);
390 * Everything else is done at a higher level.
397 error = EAFNOSUPPORT; /* XXX */
400 switch (ifr->ifr_addr.sa_family) {
411 error = EAFNOSUPPORT;
417 ifp->if_mtu = ifr->ifr_mtu;
421 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
422 LINK_STATE_UP: LINK_STATE_DOWN);
426 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
427 if ((mask & IFCAP_RXCSUM) != 0)
428 ifp->if_capenable ^= IFCAP_RXCSUM;
429 if ((mask & IFCAP_TXCSUM) != 0)
430 ifp->if_capenable ^= IFCAP_TXCSUM;
431 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
433 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
439 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
441 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
447 ifp->if_hwassist = 0;
448 if (ifp->if_capenable & IFCAP_TXCSUM)
449 ifp->if_hwassist = LO_CSUM_FEATURES;
451 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
452 ifp->if_hwassist |= LO_CSUM_FEATURES6;