xref: /freebsd/sys/net/if_disc.c (revision 12f05b84463baacfada5a79eaed061a4899d98aa)
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  #include <net/vnet.h>
54  
55  #include "opt_inet.h"
56  #include "opt_inet6.h"
57  
58  #ifdef TINY_DSMTU
59  #define	DSMTU	(1024+512)
60  #else
61  #define DSMTU	65532
62  #endif
63  
64  struct disc_softc {
65  	struct ifnet *sc_ifp;
66  };
67  
68  static int	discoutput(struct ifnet *, struct mbuf *,
69  		    const struct sockaddr *, struct route *);
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 VNET_DEFINE(struct if_clone *, disc_cloner);
78  #define	V_disc_cloner	VNET(disc_cloner)
79  
80  static int
81  disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
82  {
83  	struct ifnet		*ifp;
84  	struct disc_softc	*sc;
85  
86  	sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
87  	ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
88  	if (ifp == NULL) {
89  		free(sc, M_DISC);
90  		return (ENOSPC);
91  	}
92  
93  	ifp->if_softc = sc;
94  	if_initname(ifp, discname, unit);
95  	ifp->if_mtu = DSMTU;
96  	/*
97  	 * IFF_LOOPBACK should not be removed from disc's flags because
98  	 * it controls what PF-specific routes are magically added when
99  	 * a network address is assigned to the interface.  Things just
100  	 * won't work as intended w/o such routes because the output
101  	 * interface selection for a packet is totally route-driven.
102  	 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
103  	 * IFF_POINTOPOINT, but it would result in different properties
104  	 * of the interface.
105  	 */
106  	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
107  	ifp->if_drv_flags = IFF_DRV_RUNNING;
108  	ifp->if_ioctl = discioctl;
109  	ifp->if_output = discoutput;
110  	ifp->if_hdrlen = 0;
111  	ifp->if_addrlen = 0;
112  	ifp->if_snd.ifq_maxlen = 20;
113  	if_attach(ifp);
114  	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
115  
116  	return (0);
117  }
118  
119  static void
120  disc_clone_destroy(struct ifnet *ifp)
121  {
122  	struct disc_softc	*sc;
123  
124  	sc = ifp->if_softc;
125  
126  	bpfdetach(ifp);
127  	if_detach(ifp);
128  	if_free(ifp);
129  
130  	free(sc, M_DISC);
131  }
132  
133  static void
134  vnet_disc_init(const void *unused __unused)
135  {
136  
137  	V_disc_cloner = if_clone_simple(discname, disc_clone_create,
138  	    disc_clone_destroy, 0);
139  }
140  VNET_SYSINIT(vnet_disc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
141      vnet_disc_init, NULL);
142  
143  static void
144  vnet_disc_uninit(const void *unused __unused)
145  {
146  
147  	if_clone_detach(V_disc_cloner);
148  }
149  VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
150      vnet_disc_uninit, NULL);
151  
152  static int
153  disc_modevent(module_t mod, int type, void *data)
154  {
155  
156  	switch (type) {
157  	case MOD_LOAD:
158  	case MOD_UNLOAD:
159  		break;
160  	default:
161  		return (EOPNOTSUPP);
162  	}
163  	return (0);
164  }
165  
166  static moduledata_t disc_mod = {
167  	"if_disc",
168  	disc_modevent,
169  	NULL
170  };
171  
172  DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
173  
174  static int
175  discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
176      struct route *ro)
177  {
178  	u_int32_t af;
179  
180  	M_ASSERTPKTHDR(m);
181  
182  	/* BPF writes need to be handled specially. */
183  	if (dst->sa_family == AF_UNSPEC)
184  		bcopy(dst->sa_data, &af, sizeof(af));
185  	else
186  		af = dst->sa_family;
187  
188  	if (bpf_peers_present(ifp->if_bpf))
189  		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
190  
191  	m->m_pkthdr.rcvif = ifp;
192  
193  	if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
194  	if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
195  
196  	m_freem(m);
197  	return (0);
198  }
199  
200  /*
201   * Process an ioctl request.
202   */
203  static int
204  discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
205  {
206  	struct ifreq *ifr = (struct ifreq *)data;
207  	int error = 0;
208  
209  	switch (cmd) {
210  	case SIOCSIFADDR:
211  		ifp->if_flags |= IFF_UP;
212  
213  		/*
214  		 * Everything else is done at a higher level.
215  		 */
216  		break;
217  	case SIOCADDMULTI:
218  	case SIOCDELMULTI:
219  		if (ifr == 0) {
220  			error = EAFNOSUPPORT;		/* XXX */
221  			break;
222  		}
223  		switch (ifr->ifr_addr.sa_family) {
224  #ifdef INET
225  		case AF_INET:
226  			break;
227  #endif
228  #ifdef INET6
229  		case AF_INET6:
230  			break;
231  #endif
232  		default:
233  			error = EAFNOSUPPORT;
234  			break;
235  		}
236  		break;
237  	case SIOCSIFMTU:
238  		ifp->if_mtu = ifr->ifr_mtu;
239  		break;
240  	default:
241  		error = EINVAL;
242  	}
243  	return (error);
244  }
245