xref: /freebsd/sys/net/if_disc.c (revision 3a92d97ff0f22d21608e1c19b83104c4937523b6)
1 /*-
2  * Copyright (c) 1982, 1986, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	From: @(#)if_loop.c	8.1 (Berkeley) 6/10/93
30  * $FreeBSD$
31  */
32 
33 /*
34  * Discard interface driver for protocol testing and timing.
35  * (Based on the loopback.)
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/mbuf.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 
47 #include <net/if.h>
48 #include <net/if_var.h>
49 #include <net/if_clone.h>
50 #include <net/if_types.h>
51 #include <net/route.h>
52 #include <net/bpf.h>
53 
54 #include "opt_inet.h"
55 #include "opt_inet6.h"
56 
57 #ifdef TINY_DSMTU
58 #define	DSMTU	(1024+512)
59 #else
60 #define DSMTU	65532
61 #endif
62 
63 struct disc_softc {
64 	struct ifnet *sc_ifp;
65 };
66 
67 static int	discoutput(struct ifnet *, struct mbuf *,
68 		    const struct sockaddr *, struct route *);
69 static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
70 static int	discioctl(struct ifnet *, u_long, caddr_t);
71 static int	disc_clone_create(struct if_clone *, int, caddr_t);
72 static void	disc_clone_destroy(struct ifnet *);
73 
74 static const char discname[] = "disc";
75 static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
76 
77 static struct if_clone *disc_cloner;
78 
79 static int
80 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
81 {
82 	struct ifnet		*ifp;
83 	struct disc_softc	*sc;
84 
85 	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
86 	ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
87 	if (ifp == NULL) {
88 		free(sc, M_DISC);
89 		return (ENOSPC);
90 	}
91 
92 	ifp->if_softc = sc;
93 	if_initname(ifp, discname, unit);
94 	ifp->if_mtu = DSMTU;
95 	/*
96 	 * IFF_LOOPBACK should not be removed from disc's flags because
97 	 * it controls what PF-specific routes are magically added when
98 	 * a network address is assigned to the interface.  Things just
99 	 * won't work as intended w/o such routes because the output
100 	 * interface selection for a packet is totally route-driven.
101 	 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
102 	 * IFF_POINTOPOINT, but it would result in different properties
103 	 * of the interface.
104 	 */
105 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
106 	ifp->if_drv_flags = IFF_DRV_RUNNING;
107 	ifp->if_ioctl = discioctl;
108 	ifp->if_output = discoutput;
109 	ifp->if_hdrlen = 0;
110 	ifp->if_addrlen = 0;
111 	ifp->if_snd.ifq_maxlen = 20;
112 	if_attach(ifp);
113 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
114 
115 	return (0);
116 }
117 
118 static void
119 disc_clone_destroy(struct ifnet *ifp)
120 {
121 	struct disc_softc	*sc;
122 
123 	sc = ifp->if_softc;
124 
125 	bpfdetach(ifp);
126 	if_detach(ifp);
127 	if_free(ifp);
128 
129 	free(sc, M_DISC);
130 }
131 
132 static int
133 disc_modevent(module_t mod, int type, void *data)
134 {
135 
136 	switch (type) {
137 	case MOD_LOAD:
138 		disc_cloner = if_clone_simple(discname, disc_clone_create,
139 		    disc_clone_destroy, 0);
140 		break;
141 	case MOD_UNLOAD:
142 		if_clone_detach(disc_cloner);
143 		break;
144 	default:
145 		return (EOPNOTSUPP);
146 	}
147 	return (0);
148 }
149 
150 static moduledata_t disc_mod = {
151 	"if_disc",
152 	disc_modevent,
153 	NULL
154 };
155 
156 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
157 
158 static int
159 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
160     struct route *ro)
161 {
162 	u_int32_t af;
163 
164 	M_ASSERTPKTHDR(m);
165 
166 	/* BPF writes need to be handled specially. */
167 	if (dst->sa_family == AF_UNSPEC)
168 		bcopy(dst->sa_data, &af, sizeof(af));
169 	else
170 		af = dst->sa_family;
171 
172 	if (bpf_peers_present(ifp->if_bpf))
173 		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
174 
175 	m->m_pkthdr.rcvif = ifp;
176 
177 	ifp->if_opackets++;
178 	ifp->if_obytes += m->m_pkthdr.len;
179 
180 	m_freem(m);
181 	return (0);
182 }
183 
184 /* ARGSUSED */
185 static void
186 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
187 {
188 	RT_LOCK_ASSERT(rt);
189 	rt->rt_mtu = DSMTU;
190 }
191 
192 /*
193  * Process an ioctl request.
194  */
195 static int
196 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
197 {
198 	struct ifaddr *ifa;
199 	struct ifreq *ifr = (struct ifreq *)data;
200 	int error = 0;
201 
202 	switch (cmd) {
203 
204 	case SIOCSIFADDR:
205 		ifp->if_flags |= IFF_UP;
206 		ifa = (struct ifaddr *)data;
207 		if (ifa != 0)
208 			ifa->ifa_rtrequest = discrtrequest;
209 		/*
210 		 * Everything else is done at a higher level.
211 		 */
212 		break;
213 
214 	case SIOCADDMULTI:
215 	case SIOCDELMULTI:
216 		if (ifr == 0) {
217 			error = EAFNOSUPPORT;		/* XXX */
218 			break;
219 		}
220 		switch (ifr->ifr_addr.sa_family) {
221 
222 #ifdef INET
223 		case AF_INET:
224 			break;
225 #endif
226 #ifdef INET6
227 		case AF_INET6:
228 			break;
229 #endif
230 
231 		default:
232 			error = EAFNOSUPPORT;
233 			break;
234 		}
235 		break;
236 
237 	case SIOCSIFMTU:
238 		ifp->if_mtu = ifr->ifr_mtu;
239 		break;
240 
241 	default:
242 		error = EINVAL;
243 	}
244 	return (error);
245 }
246