2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1982, 1986, 1993
5 * The Regents of the University of California. All rights reserved.
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8 * modification, are permitted provided that the following conditions
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33 * Loopback interface driver for protocol testing and timing.
37 #include "opt_inet6.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
44 #include <sys/module.h>
45 #include <machine/bus.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 #include <sys/sysctl.h>
52 #include <net/if_var.h>
53 #include <net/if_private.h>
54 #include <net/if_clone.h>
55 #include <net/if_types.h>
56 #include <net/netisr.h>
57 #include <net/route.h>
62 #include <netinet/in.h>
63 #include <netinet/in_var.h>
68 #include <netinet/in.h>
70 #include <netinet6/in6_var.h>
71 #include <netinet/ip6.h>
74 #include <security/mac/mac_framework.h>
77 #define LOMTU (1024+512)
78 #elif defined(LARGE_LOMTU)
84 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
85 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
86 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
88 CSUM_IP_CHECKED | CSUM_IP_VALID | \
91 static int loioctl(struct ifnet *, u_long, caddr_t);
92 static int looutput(struct ifnet *ifp, struct mbuf *m,
93 const struct sockaddr *dst, struct route *ro);
95 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
98 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
99 #define V_lo_cloner VNET(lo_cloner)
102 static struct if_clone *lo_cloner;
103 static const char loname[] = "lo";
106 lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
108 if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
112 /* XXX: destroying lo0 will lead to panics. */
113 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
124 lo_clone_create(struct if_clone *ifc, char *name, size_t len,
125 struct ifc_data *ifd, struct ifnet **ifpp)
129 ifp = if_alloc(IFT_LOOP);
133 if_initname(ifp, loname, ifd->unit);
135 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
136 ifp->if_ioctl = loioctl;
137 ifp->if_output = looutput;
138 ifp->if_snd.ifq_maxlen = ifqmaxlen;
139 ifp->if_capabilities = ifp->if_capenable =
140 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
141 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
143 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
152 vnet_loif_init(const void *unused __unused)
154 struct if_clone_addreq req = {
155 .create_f = lo_clone_create,
156 .destroy_f = lo_clone_destroy,
157 .flags = IFC_F_AUTOUNIT,
159 lo_cloner = ifc_attach_cloner(loname, &req);
161 V_lo_cloner = lo_cloner;
163 struct ifc_data ifd = { .unit = 0 };
164 ifc_create_ifp(loname, &ifd, NULL);
166 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
167 vnet_loif_init, NULL);
171 vnet_loif_uninit(const void *unused __unused)
174 ifc_detach_cloner(V_lo_cloner);
177 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
178 vnet_loif_uninit, NULL);
182 loop_modevent(module_t mod, int type, void *data)
190 printf("loop module unload - not possible for this module type\n");
199 static moduledata_t loop_mod = {
205 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
208 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
216 M_ASSERTPKTHDR(m); /* check if we have the packet header */
219 error = mac_ifnet_check_transmit(ifp, m);
226 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
228 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
231 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
232 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
238 /* BPF writes need to be handled specially. */
239 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
240 bcopy(dst->sa_data, &af, sizeof(af));
242 af = RO_GET_FAMILY(ro, dst);
247 if (ifp->if_capenable & IFCAP_RXCSUM) {
248 m->m_pkthdr.csum_data = 0xffff;
249 m->m_pkthdr.csum_flags = LO_CSUM_SET;
251 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
256 * XXX-BZ for now always claim the checksum is good despite
257 * any interface flags. This is a workaround for 9.1-R and
258 * a proper solution ought to be sought later.
260 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
261 m->m_pkthdr.csum_data = 0xffff;
262 m->m_pkthdr.csum_flags = LO_CSUM_SET;
265 m->m_pkthdr.csum_data = 0xffff;
266 m->m_pkthdr.csum_flags = LO_CSUM_SET;
268 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
271 printf("looutput: af=%d unexpected\n", af);
273 return (EAFNOSUPPORT);
276 return (if_simloop(ifp, m, af, 0));
282 * This function is to support software emulation of hardware loopback,
283 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
284 * hear their own broadcasts, we create a copy of the packet that we
285 * would normally receive via a hardware loopback.
287 * This function expects the packet to include the media header of length hlen.
290 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
295 m_tag_delete_nonpersistent(m);
296 m->m_pkthdr.rcvif = ifp;
299 mac_ifnet_create_mbuf(ifp, m);
303 * Let BPF see incoming packet in the following manner:
304 * - Emulated packet loopback for a simplex interface
305 * (net/if_ethersubr.c)
306 * -> passes it to ifp's BPF
307 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
308 * -> not passes it to any BPF
309 * - Normal packet loopback from myself to myself (net/if_loop.c)
310 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
313 if (bpf_peers_present(ifp->if_bpf)) {
314 bpf_mtap(ifp->if_bpf, m);
317 if (bpf_peers_present(V_loif->if_bpf)) {
318 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
319 /* XXX beware sizeof(af) != 4 */
323 * We need to prepend the address family.
325 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
330 /* Strip away media header */
333 #ifndef __NO_STRICT_ALIGNMENT
335 * Some archs do not like unaligned data, so
336 * we move data down in the first mbuf.
338 if (mtod(m, vm_offset_t) & 3) {
339 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
341 (char *)(mtod(m, vm_offset_t)
342 - (mtod(m, vm_offset_t) & 3)),
344 m->m_data -= (mtod(m,vm_offset_t) & 3);
349 /* Deliver to upper layer protocol */
358 m->m_flags |= M_LOOP;
363 printf("if_simloop: can't handle af=%d\n", af);
365 return (EAFNOSUPPORT);
367 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
368 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
369 netisr_queue(isr, m); /* mbuf is free'd on failure. */
374 * Process an ioctl request.
377 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
379 struct ifreq *ifr = (struct ifreq *)data;
384 ifp->if_flags |= IFF_UP;
385 ifp->if_drv_flags |= IFF_DRV_RUNNING;
386 if_link_state_change(ifp, LINK_STATE_UP);
388 * Everything else is done at a higher level.
395 error = EAFNOSUPPORT; /* XXX */
398 switch (ifr->ifr_addr.sa_family) {
409 error = EAFNOSUPPORT;
415 ifp->if_mtu = ifr->ifr_mtu;
419 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
420 LINK_STATE_UP: LINK_STATE_DOWN);
424 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
425 if ((mask & IFCAP_RXCSUM) != 0)
426 ifp->if_capenable ^= IFCAP_RXCSUM;
427 if ((mask & IFCAP_TXCSUM) != 0)
428 ifp->if_capenable ^= IFCAP_TXCSUM;
429 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
431 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
437 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
439 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
445 ifp->if_hwassist = 0;
446 if (ifp->if_capenable & IFCAP_TXCSUM)
447 ifp->if_hwassist = LO_CSUM_FEATURES;
449 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
450 ifp->if_hwassist |= LO_CSUM_FEATURES6;