if_disc.c revision 51646 
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 51646 1999-09-25 12:06:01Z phk $
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
56#ifdef TINY_DSMTU
57#define	DSMTU	(1024+512)
58#else
59#define DSMTU	65532
60#endif
61
62static void discattach __P((void *dummy));
63PSEUDO_SET(discattach, if_disc);
64
65static struct	ifnet discif;
66static int discoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
67		    struct rtentry *);
68static void discrtrequest(int cmd, struct rtentry *rt, struct sockaddr *sa);
69static int discioctl(struct ifnet *, u_long, caddr_t);
70
71/* ARGSUSED */
72static void
73discattach(dummy)
74	void *dummy;
75{
76	register struct ifnet *ifp = &discif;
77
78	ifp->if_name = "ds";
79	ifp->if_mtu = DSMTU;
80	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
81	ifp->if_ioctl = discioctl;
82	ifp->if_output = discoutput;
83	ifp->if_type = IFT_LOOP;
84	ifp->if_hdrlen = 0;
85	ifp->if_addrlen = 0;
86	if_attach(ifp);
87	bpfattach(ifp, DLT_NULL, sizeof(u_int));
88}
89
90static int
91discoutput(ifp, m, dst, rt)
92	struct ifnet *ifp;
93	register struct mbuf *m;
94	struct sockaddr *dst;
95	register struct rtentry *rt;
96{
97	if ((m->m_flags & M_PKTHDR) == 0)
98		panic("discoutput no HDR");
99	/* BPF write needs to be handled specially */
100	if (dst->sa_family == AF_UNSPEC) {
101		dst->sa_family = *(mtod(m, int *));
102		m->m_len -= sizeof(int);
103		m->m_pkthdr.len -= sizeof(int);
104		m->m_data += sizeof(int);
105	}
106
107	if (discif.if_bpf) {
108		/*
109		 * We need to prepend the address family as
110		 * a four byte field.  Cons up a dummy header
111		 * to pacify bpf.  This is safe because bpf
112		 * will only read from the mbuf (i.e., it won't
113		 * try to free it or keep a pointer a to it).
114		 */
115		struct mbuf m0;
116		u_int af = dst->sa_family;
117
118		m0.m_next = m;
119		m0.m_len = 4;
120		m0.m_data = (char *)&af;
121
122		bpf_mtap(&discif, &m0);
123	}
124	m->m_pkthdr.rcvif = ifp;
125
126	ifp->if_opackets++;
127	ifp->if_obytes += m->m_pkthdr.len;
128
129	m_freem(m);
130	return 0;
131}
132
133/* ARGSUSED */
134static void
135discrtrequest(cmd, rt, sa)
136	int cmd;
137	struct rtentry *rt;
138	struct sockaddr *sa;
139{
140	if (rt)
141		rt->rt_rmx.rmx_mtu = DSMTU;
142}
143
144/*
145 * Process an ioctl request.
146 */
147/* ARGSUSED */
148static int
149discioctl(ifp, cmd, data)
150	register struct ifnet *ifp;
151	u_long cmd;
152	caddr_t data;
153{
154	register struct ifaddr *ifa;
155	register struct ifreq *ifr = (struct ifreq *)data;
156	register int error = 0;
157
158	switch (cmd) {
159
160	case SIOCSIFADDR:
161		ifp->if_flags |= IFF_UP;
162		ifa = (struct ifaddr *)data;
163		if (ifa != 0)
164			ifa->ifa_rtrequest = discrtrequest;
165		/*
166		 * Everything else is done at a higher level.
167		 */
168		break;
169
170	case SIOCADDMULTI:
171	case SIOCDELMULTI:
172		if (ifr == 0) {
173			error = EAFNOSUPPORT;		/* XXX */
174			break;
175		}
176		switch (ifr->ifr_addr.sa_family) {
177
178#ifdef INET
179		case AF_INET:
180			break;
181#endif
182
183		default:
184			error = EAFNOSUPPORT;
185			break;
186		}
187		break;
188
189	case SIOCSIFMTU:
190		ifp->if_mtu = ifr->ifr_mtu;
191		break;
192
193	default:
194		error = EINVAL;
195	}
196	return (error);
197}
198