xref: /freebsd/sys/net/if_disc.c (revision 74bf4e164ba5851606a27d4feff27717452583e5)
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_clone.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
51 #include <net/bpf.h>
52 
53 #include "opt_inet.h"
54 #include "opt_inet6.h"
55 
56 #ifdef TINY_DSMTU
57 #define	DSMTU	(1024+512)
58 #else
59 #define DSMTU	65532
60 #endif
61 
62 #define DISCNAME	"disc"
63 
64 struct disc_softc {
65 	struct ifnet sc_if;	/* must be first */
66 	LIST_ENTRY(disc_softc) sc_list;
67 };
68 
69 static int	discoutput(struct ifnet *, struct mbuf *,
70 		    struct sockaddr *, struct rtentry *);
71 static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
72 static int	discioctl(struct ifnet *, u_long, caddr_t);
73 static int	disc_clone_create(struct if_clone *, int);
74 static void	disc_clone_destroy(struct ifnet *);
75 
76 static struct mtx disc_mtx;
77 static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
78 static LIST_HEAD(, disc_softc) disc_softc_list;
79 
80 IFC_SIMPLE_DECLARE(disc, 0);
81 
82 static int
83 disc_clone_create(struct if_clone *ifc, int unit)
84 {
85 	struct ifnet		*ifp;
86 	struct disc_softc	*sc;
87 
88 	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
89 
90 	ifp = &sc->sc_if;
91 
92 	ifp->if_softc = sc;
93 	if_initname(ifp, ifc->ifc_name, unit);
94 	ifp->if_mtu = DSMTU;
95 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
96 	ifp->if_ioctl = discioctl;
97 	ifp->if_output = discoutput;
98 	ifp->if_type = IFT_LOOP;
99 	ifp->if_hdrlen = 0;
100 	ifp->if_addrlen = 0;
101 	ifp->if_snd.ifq_maxlen = 20;
102 	if_attach(ifp);
103 	bpfattach(ifp, DLT_NULL, sizeof(u_int));
104 	mtx_lock(&disc_mtx);
105 	LIST_INSERT_HEAD(&disc_softc_list, sc, sc_list);
106 	mtx_unlock(&disc_mtx);
107 
108 	return (0);
109 }
110 
111 static void
112 disc_destroy(struct disc_softc *sc)
113 {
114 
115 	bpfdetach(&sc->sc_if);
116 	if_detach(&sc->sc_if);
117 
118 	free(sc, M_DISC);
119 }
120 
121 static void
122 disc_clone_destroy(struct ifnet *ifp)
123 {
124 	struct disc_softc	*sc;
125 
126 	sc = ifp->if_softc;
127 	mtx_lock(&disc_mtx);
128 	LIST_REMOVE(sc, sc_list);
129 	mtx_unlock(&disc_mtx);
130 
131 	disc_destroy(sc);
132 }
133 
134 static int
135 disc_modevent(module_t mod, int type, void *data)
136 {
137 	struct disc_softc *sc;
138 
139 	switch (type) {
140 	case MOD_LOAD:
141 		mtx_init(&disc_mtx, "disc_mtx", NULL, MTX_DEF);
142 		LIST_INIT(&disc_softc_list);
143 		if_clone_attach(&disc_cloner);
144 		break;
145 	case MOD_UNLOAD:
146 		if_clone_detach(&disc_cloner);
147 
148 		mtx_lock(&disc_mtx);
149 		while ((sc = LIST_FIRST(&disc_softc_list)) != NULL) {
150 			LIST_REMOVE(sc, sc_list);
151 			mtx_unlock(&disc_mtx);
152 			disc_destroy(sc);
153 			mtx_lock(&disc_mtx);
154 		}
155 		mtx_unlock(&disc_mtx);
156 		mtx_destroy(&disc_mtx);
157 		break;
158 	default:
159 		return (EOPNOTSUPP);
160 	}
161 	return (0);
162 }
163 
164 static moduledata_t disc_mod = {
165 	"if_disc",
166 	disc_modevent,
167 	NULL
168 };
169 
170 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
171 
172 static int
173 discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
174     struct rtentry *rt)
175 {
176 
177 	M_ASSERTPKTHDR(m);
178 
179 	/* BPF write needs to be handled specially */
180 	if (dst->sa_family == AF_UNSPEC) {
181 		dst->sa_family = *(mtod(m, int *));
182 		m->m_len -= sizeof(int);
183 		m->m_pkthdr.len -= sizeof(int);
184 		m->m_data += sizeof(int);
185 	}
186 
187 	if (ifp->if_bpf) {
188 		u_int af = dst->sa_family;
189 		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
190 	}
191 	m->m_pkthdr.rcvif = ifp;
192 
193 	ifp->if_opackets++;
194 	ifp->if_obytes += m->m_pkthdr.len;
195 
196 	m_freem(m);
197 	return (0);
198 }
199 
200 /* ARGSUSED */
201 static void
202 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
203 {
204 	RT_LOCK_ASSERT(rt);
205 
206 	if (rt)
207 		rt->rt_rmx.rmx_mtu = DSMTU;
208 }
209 
210 /*
211  * Process an ioctl request.
212  */
213 static int
214 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
215 {
216 	struct ifaddr *ifa;
217 	struct ifreq *ifr = (struct ifreq *)data;
218 	int error = 0;
219 
220 	switch (cmd) {
221 
222 	case SIOCSIFADDR:
223 		ifp->if_flags |= IFF_UP;
224 		ifa = (struct ifaddr *)data;
225 		if (ifa != 0)
226 			ifa->ifa_rtrequest = discrtrequest;
227 		/*
228 		 * Everything else is done at a higher level.
229 		 */
230 		break;
231 
232 	case SIOCADDMULTI:
233 	case SIOCDELMULTI:
234 		if (ifr == 0) {
235 			error = EAFNOSUPPORT;		/* XXX */
236 			break;
237 		}
238 		switch (ifr->ifr_addr.sa_family) {
239 
240 #ifdef INET
241 		case AF_INET:
242 			break;
243 #endif
244 #ifdef INET6
245 		case AF_INET6:
246 			break;
247 #endif
248 
249 		default:
250 			error = EAFNOSUPPORT;
251 			break;
252 		}
253 		break;
254 
255 	case SIOCSIFMTU:
256 		ifp->if_mtu = ifr->ifr_mtu;
257 		break;
258 
259 	default:
260 		error = EINVAL;
261 	}
262 	return (error);
263 }
264