xref: /freebsd/sys/net/if_disc.c (revision 282a3889ebf826db9839be296ff1dd903f6d6d6e)
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_ifp;
66 };
67 
68 static int	discoutput(struct ifnet *, struct mbuf *,
69 		    struct sockaddr *, struct rtentry *);
70 static void	discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
71 static int	discioctl(struct ifnet *, u_long, caddr_t);
72 static int	disc_clone_create(struct if_clone *, int, caddr_t);
73 static void	disc_clone_destroy(struct ifnet *);
74 
75 static MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
76 
77 IFC_SIMPLE_DECLARE(disc, 0);
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, ifc->ifc_name, unit);
94 	ifp->if_mtu = DSMTU;
95 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
96 	ifp->if_drv_flags = IFF_DRV_RUNNING;
97 	ifp->if_ioctl = discioctl;
98 	ifp->if_output = discoutput;
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_int32_t));
104 
105 	return (0);
106 }
107 
108 static void
109 disc_clone_destroy(struct ifnet *ifp)
110 {
111 	struct disc_softc	*sc;
112 
113 	sc = ifp->if_softc;
114 
115 	bpfdetach(ifp);
116 	if_detach(ifp);
117 	if_free(ifp);
118 
119 	free(sc, M_DISC);
120 }
121 
122 static int
123 disc_modevent(module_t mod, int type, void *data)
124 {
125 
126 	switch (type) {
127 	case MOD_LOAD:
128 		if_clone_attach(&disc_cloner);
129 		break;
130 	case MOD_UNLOAD:
131 		if_clone_detach(&disc_cloner);
132 		break;
133 	default:
134 		return (EOPNOTSUPP);
135 	}
136 	return (0);
137 }
138 
139 static moduledata_t disc_mod = {
140 	"if_disc",
141 	disc_modevent,
142 	NULL
143 };
144 
145 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
146 
147 static int
148 discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
149     struct rtentry *rt)
150 {
151 	u_int32_t af;
152 
153 	M_ASSERTPKTHDR(m);
154 
155 	/* BPF writes need to be handled specially. */
156 	if (dst->sa_family == AF_UNSPEC) {
157 		bcopy(dst->sa_data, &af, sizeof(af));
158 		dst->sa_family = af;
159 	}
160 
161 	if (bpf_peers_present(ifp->if_bpf)) {
162 		u_int af = dst->sa_family;
163 		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
164 	}
165 	m->m_pkthdr.rcvif = ifp;
166 
167 	ifp->if_opackets++;
168 	ifp->if_obytes += m->m_pkthdr.len;
169 
170 	m_freem(m);
171 	return (0);
172 }
173 
174 /* ARGSUSED */
175 static void
176 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
177 {
178 	RT_LOCK_ASSERT(rt);
179 	rt->rt_rmx.rmx_mtu = DSMTU;
180 }
181 
182 /*
183  * Process an ioctl request.
184  */
185 static int
186 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
187 {
188 	struct ifaddr *ifa;
189 	struct ifreq *ifr = (struct ifreq *)data;
190 	int error = 0;
191 
192 	switch (cmd) {
193 
194 	case SIOCSIFADDR:
195 		ifp->if_flags |= IFF_UP;
196 		ifa = (struct ifaddr *)data;
197 		if (ifa != 0)
198 			ifa->ifa_rtrequest = discrtrequest;
199 		/*
200 		 * Everything else is done at a higher level.
201 		 */
202 		break;
203 
204 	case SIOCADDMULTI:
205 	case SIOCDELMULTI:
206 		if (ifr == 0) {
207 			error = EAFNOSUPPORT;		/* XXX */
208 			break;
209 		}
210 		switch (ifr->ifr_addr.sa_family) {
211 
212 #ifdef INET
213 		case AF_INET:
214 			break;
215 #endif
216 #ifdef INET6
217 		case AF_INET6:
218 			break;
219 #endif
220 
221 		default:
222 			error = EAFNOSUPPORT;
223 			break;
224 		}
225 		break;
226 
227 	case SIOCSIFMTU:
228 		ifp->if_mtu = ifr->ifr_mtu;
229 		break;
230 
231 	default:
232 		error = EINVAL;
233 	}
234 	return (error);
235 }
236