1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1993
5 *	The Regents of the University of California.  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 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.
18 *
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
29 * SUCH DAMAGE.
30 */
31
32/*
33 * Loopback interface driver for protocol testing and timing.
34 */
35
36#include "opt_inet.h"
37#include "opt_inet6.h"
38#include "opt_rss.h"
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/kernel.h>
43#include <sys/mbuf.h>
44#include <sys/module.h>
45#include <machine/bus.h>
46#include <sys/rman.h>
47#include <sys/socket.h>
48#include <sys/sockio.h>
49#include <sys/sysctl.h>
50
51#include <net/if.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>
58#include <net/bpf.h>
59#include <net/vnet.h>
60
61#ifdef	INET
62#include <netinet/in.h>
63#include <netinet/in_var.h>
64#endif
65
66#ifdef INET6
67#ifndef INET
68#include <netinet/in.h>
69#endif
70#include <netinet6/in6_var.h>
71#include <netinet/ip6.h>
72#endif
73
74#include <security/mac/mac_framework.h>
75
76#ifdef TINY_LOMTU
77#define	LOMTU	(1024+512)
78#elif defined(LARGE_LOMTU)
79#define LOMTU	131072
80#else
81#define LOMTU	16384
82#endif
83
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 | \
87				    CSUM_PSEUDO_HDR | \
88				    CSUM_IP_CHECKED | CSUM_IP_VALID | \
89				    CSUM_SCTP_VALID)
90
91static int	loioctl(struct ifnet *, u_long, caddr_t);
92static int	looutput(struct ifnet *ifp, struct mbuf *m,
93		    const struct sockaddr *dst, struct route *ro);
94
95VNET_DEFINE(struct ifnet *, loif);	/* Used externally */
96
97#ifdef VIMAGE
98VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
99#define	V_lo_cloner		VNET(lo_cloner)
100#endif
101
102static struct if_clone *lo_cloner;
103static const char loname[] = "lo";
104
105static int
106lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
107{
108	if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
109		return (EINVAL);
110
111#ifndef VIMAGE
112	/* XXX: destroying lo0 will lead to panics. */
113	KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
114#endif
115
116	bpfdetach(ifp);
117	if_detach(ifp);
118	if_free(ifp);
119
120	return (0);
121}
122
123static int
124lo_clone_create(struct if_clone *ifc, char *name, size_t len,
125    struct ifc_data *ifd, struct ifnet **ifpp)
126{
127	struct ifnet *ifp;
128
129	ifp = if_alloc(IFT_LOOP);
130	if (ifp == NULL)
131		return (ENOSPC);
132
133	if_initname(ifp, loname, ifd->unit);
134	ifp->if_mtu = LOMTU;
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;
142	if_attach(ifp);
143	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
144	if (V_loif == NULL)
145		V_loif = ifp;
146	*ifpp = ifp;
147
148	return (0);
149}
150
151static void
152vnet_loif_init(const void *unused __unused)
153{
154	struct if_clone_addreq req = {
155		.create_f = lo_clone_create,
156		.destroy_f = lo_clone_destroy,
157		.flags = IFC_F_AUTOUNIT,
158	};
159	lo_cloner = ifc_attach_cloner(loname, &req);
160#ifdef VIMAGE
161	V_lo_cloner = lo_cloner;
162#endif
163	struct ifc_data ifd = { .unit = 0 };
164	ifc_create_ifp(loname, &ifd, NULL);
165}
166VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
167    vnet_loif_init, NULL);
168
169#ifdef VIMAGE
170static void
171vnet_loif_uninit(const void *unused __unused)
172{
173
174	ifc_detach_cloner(V_lo_cloner);
175	V_loif = NULL;
176}
177VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
178    vnet_loif_uninit, NULL);
179#endif
180
181static int
182loop_modevent(module_t mod, int type, void *data)
183{
184
185	switch (type) {
186	case MOD_LOAD:
187		break;
188
189	case MOD_UNLOAD:
190		printf("loop module unload - not possible for this module type\n");
191		return (EINVAL);
192
193	default:
194		return (EOPNOTSUPP);
195	}
196	return (0);
197}
198
199static moduledata_t loop_mod = {
200	"if_lo",
201	loop_modevent,
202	0
203};
204
205DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
206
207static int
208looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
209    struct route *ro)
210{
211	u_int32_t af;
212#ifdef MAC
213	int error;
214#endif
215
216	M_ASSERTPKTHDR(m); /* check if we have the packet header */
217
218#ifdef MAC
219	error = mac_ifnet_check_transmit(ifp, m);
220	if (error) {
221		m_freem(m);
222		return (error);
223	}
224#endif
225
226	if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
227		m_freem(m);
228		return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
229	}
230
231	if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
232	if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
233
234#ifdef RSS
235	M_HASHTYPE_CLEAR(m);
236#endif
237
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));
241	else
242		af = RO_GET_FAMILY(ro, dst);
243
244#if 1	/* XXX */
245	switch (af) {
246	case AF_INET:
247		if (ifp->if_capenable & IFCAP_RXCSUM) {
248			m->m_pkthdr.csum_data = 0xffff;
249			m->m_pkthdr.csum_flags = LO_CSUM_SET;
250		}
251		m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
252		break;
253	case AF_INET6:
254#if 0
255		/*
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.
259		 */
260		if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
261			m->m_pkthdr.csum_data = 0xffff;
262			m->m_pkthdr.csum_flags = LO_CSUM_SET;
263		}
264#else
265		m->m_pkthdr.csum_data = 0xffff;
266		m->m_pkthdr.csum_flags = LO_CSUM_SET;
267#endif
268		m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
269		break;
270	default:
271		printf("looutput: af=%d unexpected\n", af);
272		m_freem(m);
273		return (EAFNOSUPPORT);
274	}
275#endif
276	return (if_simloop(ifp, m, af, 0));
277}
278
279/*
280 * if_simloop()
281 *
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.
286 *
287 * This function expects the packet to include the media header of length hlen.
288 */
289int
290if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
291{
292	int isr;
293
294	M_ASSERTPKTHDR(m);
295	m_tag_delete_nonpersistent(m);
296	m->m_pkthdr.rcvif = ifp;
297
298#ifdef MAC
299	mac_ifnet_create_mbuf(ifp, m);
300#endif
301
302	/*
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)
311	 */
312	if (hlen > 0) {
313		if (bpf_peers_present(ifp->if_bpf)) {
314			bpf_mtap(ifp->if_bpf, m);
315		}
316	} else {
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 */
320				u_int32_t af1 = af;
321
322				/*
323				 * We need to prepend the address family.
324				 */
325				bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
326			}
327		}
328	}
329
330	/* Strip away media header */
331	if (hlen > 0) {
332		m_adj(m, hlen);
333#ifndef __NO_STRICT_ALIGNMENT
334		/*
335		 * Some archs do not like unaligned data, so
336		 * we move data down in the first mbuf.
337		 */
338		if (mtod(m, vm_offset_t) & 3) {
339			KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
340			bcopy(m->m_data,
341			    (char *)(mtod(m, vm_offset_t)
342				- (mtod(m, vm_offset_t) & 3)),
343			    m->m_len);
344			m->m_data -= (mtod(m,vm_offset_t) & 3);
345		}
346#endif
347	}
348
349	/* Deliver to upper layer protocol */
350	switch (af) {
351#ifdef INET
352	case AF_INET:
353		isr = NETISR_IP;
354		break;
355#endif
356#ifdef INET6
357	case AF_INET6:
358		m->m_flags |= M_LOOP;
359		isr = NETISR_IPV6;
360		break;
361#endif
362	default:
363		printf("if_simloop: can't handle af=%d\n", af);
364		m_freem(m);
365		return (EAFNOSUPPORT);
366	}
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. */
370	return (0);
371}
372
373/*
374 * Process an ioctl request.
375 */
376static int
377loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
378{
379	struct ifreq *ifr = (struct ifreq *)data;
380	int error = 0, mask;
381
382	switch (cmd) {
383	case SIOCSIFADDR:
384		ifp->if_flags |= IFF_UP;
385		ifp->if_drv_flags |= IFF_DRV_RUNNING;
386		if_link_state_change(ifp, LINK_STATE_UP);
387		/*
388		 * Everything else is done at a higher level.
389		 */
390		break;
391
392	case SIOCADDMULTI:
393	case SIOCDELMULTI:
394		if (ifr == NULL) {
395			error = EAFNOSUPPORT;		/* XXX */
396			break;
397		}
398		switch (ifr->ifr_addr.sa_family) {
399#ifdef INET
400		case AF_INET:
401			break;
402#endif
403#ifdef INET6
404		case AF_INET6:
405			break;
406#endif
407
408		default:
409			error = EAFNOSUPPORT;
410			break;
411		}
412		break;
413
414	case SIOCSIFMTU:
415		ifp->if_mtu = ifr->ifr_mtu;
416		break;
417
418	case SIOCSIFFLAGS:
419		if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
420		    LINK_STATE_UP: LINK_STATE_DOWN);
421		break;
422
423	case SIOCSIFCAP:
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) {
430#if 0
431			ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
432#else
433			error = EOPNOTSUPP;
434			break;
435#endif
436		}
437		if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
438#if 0
439			ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
440#else
441			error = EOPNOTSUPP;
442			break;
443#endif
444		}
445		ifp->if_hwassist = 0;
446		if (ifp->if_capenable & IFCAP_TXCSUM)
447			ifp->if_hwassist = LO_CSUM_FEATURES;
448#if 0
449		if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
450			ifp->if_hwassist |= LO_CSUM_FEATURES6;
451#endif
452		break;
453
454	default:
455		error = EINVAL;
456	}
457	return (error);
458}
459