if_disc.c revision 11921 
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 *	$Id: if_disc.c,v 1.7 1995/09/22 17:57:47 wollman Exp $
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/errno.h>
48#include <sys/ioctl.h>
49#include <sys/time.h>
50#include <machine/cpu.h>
51
52#include <net/if.h>
53#include <net/if_types.h>
54#include <net/netisr.h>
55#include <net/route.h>
56#include <net/bpf.h>
57
58#ifdef	INET
59#include <netinet/in.h>
60#include <netinet/in_systm.h>
61#include <netinet/in_var.h>
62#include <netinet/ip.h>
63#endif
64
65#ifdef NS
66#include <netns/ns.h>
67#include <netns/ns_if.h>
68#endif
69
70#ifdef ISO
71#include <netiso/iso.h>
72#include <netiso/iso_var.h>
73#endif
74
75#include "bpfilter.h"
76
77#ifdef TINY_DSMTU
78#define	DSMTU	(1024+512)
79#else
80#define DSMTU	65532
81#endif
82
83static void discattach __P((void *udata));
84PSEUDO_SET(discattach, if_disc);
85
86static struct	ifnet dsif;
87static int dsoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
88		    struct rtentry *);
89static int dsioctl(struct ifnet *, int, caddr_t);
90
91/* ARGSUSED */
92static void
93discattach(udata)
94	void *udata;
95{
96	register struct ifnet *ifp = &dsif;
97
98	ifp->if_name = "ds";
99	ifp->if_mtu = DSMTU;
100	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
101	ifp->if_ioctl = dsioctl;
102	ifp->if_output = dsoutput;
103	ifp->if_type = IFT_LOOP;
104	ifp->if_hdrlen = 0;
105	ifp->if_addrlen = 0;
106	if_attach(ifp);
107#if NBPFILTER > 0
108	bpfattach(&ifp->if_bpf, ifp, DLT_NULL, sizeof(u_int));
109#endif
110}
111
112static int
113dsoutput(ifp, m, dst, rt)
114	struct ifnet *ifp;
115	register struct mbuf *m;
116	struct sockaddr *dst;
117	register struct rtentry *rt;
118{
119	if ((m->m_flags & M_PKTHDR) == 0)
120		panic("dsoutput no HDR");
121	ifp->if_lastchange = time;
122#if NBPFILTER > 0
123	/* BPF write needs to be handled specially */
124	if (dst->sa_family == AF_UNSPEC) {
125		dst->sa_family = *(mtod(m, int *));
126		m->m_len -= sizeof(int);
127		m->m_pkthdr.len -= sizeof(int);
128		m->m_data += sizeof(int);
129	}
130
131	if (dsif.if_bpf) {
132		/*
133		 * We need to prepend the address family as
134		 * a four byte field.  Cons up a dummy header
135		 * to pacify bpf.  This is safe because bpf
136		 * will only read from the mbuf (i.e., it won't
137		 * try to free it or keep a pointer a to it).
138		 */
139		struct mbuf m0;
140		u_int af = dst->sa_family;
141
142		m0.m_next = m;
143		m0.m_len = 4;
144		m0.m_data = (char *)&af;
145
146		bpf_mtap(dsif.if_bpf, &m0);
147	}
148#endif
149	m->m_pkthdr.rcvif = ifp;
150
151	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
152		m_freem(m);
153		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
154		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
155	}
156	ifp->if_opackets++;
157	ifp->if_obytes += m->m_pkthdr.len;
158
159	m_freem(m);
160	return 0;
161}
162
163/* ARGSUSED */
164static void
165dsrtrequest(cmd, rt, sa)
166	int cmd;
167	struct rtentry *rt;
168	struct sockaddr *sa;
169{
170	if (rt)
171		rt->rt_rmx.rmx_mtu = DSMTU;
172}
173
174/*
175 * Process an ioctl request.
176 */
177/* ARGSUSED */
178int
179dsioctl(ifp, cmd, data)
180	register struct ifnet *ifp;
181	int cmd;
182	caddr_t data;
183{
184	register struct ifaddr *ifa;
185	register struct ifreq *ifr = (struct ifreq *)data;
186	register int error = 0;
187
188	switch (cmd) {
189
190	case SIOCSIFADDR:
191		ifp->if_flags |= IFF_UP;
192		ifa = (struct ifaddr *)data;
193		if (ifa != 0)
194			ifa->ifa_rtrequest = dsrtrequest;
195		/*
196		 * Everything else is done at a higher level.
197		 */
198		break;
199
200	case SIOCADDMULTI:
201	case SIOCDELMULTI:
202		if (ifr == 0) {
203			error = EAFNOSUPPORT;		/* XXX */
204			break;
205		}
206		switch (ifr->ifr_addr.sa_family) {
207
208#ifdef INET
209		case AF_INET:
210			break;
211#endif
212
213		default:
214			error = EAFNOSUPPORT;
215			break;
216		}
217		break;
218
219	case SIOCSIFMTU:
220		ifp->if_mtu = ifr->ifr_mtu;
221		break;
222
223	default:
224		error = EINVAL;
225	}
226	return (error);
227}
228