if_disc.c revision 54263 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	From: @(#)if_loop.c	8.1 (Berkeley) 6/10/93
34 * $FreeBSD: head/sys/net/if_disc.c 54263 1999-12-07 17:39:16Z shin $
35 */
36
37/*
38 * Discard interface driver for protocol testing and timing.
39 * (Based on the loopback.)
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/mbuf.h>
46#include <sys/socket.h>
47#include <sys/sockio.h>
48
49#include <net/if.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
63static void discattach __P((void *dummy));
64PSEUDO_SET(discattach, if_disc);
65
66static struct	ifnet discif;
67static int discoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
68		    struct rtentry *);
69static void discrtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa);
70static int discioctl(struct ifnet *, u_long, caddr_t);
71
72/* ARGSUSED */
73static void
74discattach(dummy)
75	void *dummy;
76{
77	register struct ifnet *ifp = &discif;
78
79	ifp->if_name = "ds";
80	ifp->if_mtu = DSMTU;
81	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
82	ifp->if_ioctl = discioctl;
83	ifp->if_output = discoutput;
84	ifp->if_type = IFT_LOOP;
85	ifp->if_hdrlen = 0;
86	ifp->if_addrlen = 0;
87	ifp->if_snd.ifq_maxlen = 20;
88	if_attach(ifp);
89	bpfattach(ifp, DLT_NULL, sizeof(u_int));
90}
91
92static int
93discoutput(ifp, m, dst, rt)
94	struct ifnet *ifp;
95	register struct mbuf *m;
96	struct sockaddr *dst;
97	register struct rtentry *rt;
98{
99	if ((m->m_flags & M_PKTHDR) == 0)
100		panic("discoutput no HDR");
101	/* BPF write needs to be handled specially */
102	if (dst->sa_family == AF_UNSPEC) {
103		dst->sa_family = *(mtod(m, int *));
104		m->m_len -= sizeof(int);
105		m->m_pkthdr.len -= sizeof(int);
106		m->m_data += sizeof(int);
107	}
108
109	if (discif.if_bpf) {
110		/*
111		 * We need to prepend the address family as
112		 * a four byte field.  Cons up a dummy header
113		 * to pacify bpf.  This is safe because bpf
114		 * will only read from the mbuf (i.e., it won't
115		 * try to free it or keep a pointer a to it).
116		 */
117		struct mbuf m0;
118		u_int af = dst->sa_family;
119
120		m0.m_next = m;
121		m0.m_len = 4;
122		m0.m_data = (char *)&af;
123
124		bpf_mtap(&discif, &m0);
125	}
126	m->m_pkthdr.rcvif = ifp;
127
128	ifp->if_opackets++;
129	ifp->if_obytes += m->m_pkthdr.len;
130
131	m_freem(m);
132	return 0;
133}
134
135/* ARGSUSED */
136static void
137discrtrequest(cmd, rt, sa)
138	int cmd;
139	struct rtentry *rt;
140	struct sockaddr *sa;
141{
142	if (rt)
143		rt->rt_rmx.rmx_mtu = DSMTU;
144}
145
146/*
147 * Process an ioctl request.
148 */
149/* ARGSUSED */
150static int
151discioctl(ifp, cmd, data)
152	register struct ifnet *ifp;
153	u_long cmd;
154	caddr_t data;
155{
156	register struct ifaddr *ifa;
157	register struct ifreq *ifr = (struct ifreq *)data;
158	register int error = 0;
159
160	switch (cmd) {
161
162	case SIOCSIFADDR:
163		ifp->if_flags |= IFF_UP;
164		ifa = (struct ifaddr *)data;
165		if (ifa != 0)
166			ifa->ifa_rtrequest = discrtrequest;
167		/*
168		 * Everything else is done at a higher level.
169		 */
170		break;
171
172	case SIOCADDMULTI:
173	case SIOCDELMULTI:
174		if (ifr == 0) {
175			error = EAFNOSUPPORT;		/* XXX */
176			break;
177		}
178		switch (ifr->ifr_addr.sa_family) {
179
180#ifdef INET
181		case AF_INET:
182			break;
183#endif
184#ifdef INET6
185		case AF_INET6:
186			break;
187#endif
188
189		default:
190			error = EAFNOSUPPORT;
191			break;
192		}
193		break;
194
195	case SIOCSIFMTU:
196		ifp->if_mtu = ifr->ifr_mtu;
197		break;
198
199	default:
200		error = EINVAL;
201	}
202	return (error);
203}
204