xref: /freebsd/sys/net/if_loop.c (revision 02f2e93b60c2b91feac8f45c4c889a5a8e40d8a2)
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  *	@(#)if_loop.c	8.1 (Berkeley) 6/10/93
34  * $Id: if_loop.c,v 1.26 1997/03/24 11:33:12 bde Exp $
35  */
36 
37 /*
38  * Loopback interface driver for protocol testing and timing.
39  */
40 #include "loop.h"
41 #if NLOOP > 0
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/mbuf.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 
50 #include <net/if.h>
51 #include <net/if_types.h>
52 #include <net/netisr.h>
53 #include <net/route.h>
54 #include <net/bpf.h>
55 
56 #ifdef	INET
57 #include <netinet/in.h>
58 #include <netinet/in_var.h>
59 #endif
60 
61 #ifdef IPX
62 #include <netipx/ipx.h>
63 #include <netipx/ipx_if.h>
64 #endif
65 
66 #ifdef NS
67 #include <netns/ns.h>
68 #include <netns/ns_if.h>
69 #endif
70 
71 #ifdef ISO
72 #include <netiso/iso.h>
73 #include <netiso/iso_var.h>
74 #endif
75 
76 #ifdef NETATALK
77 #include <netatalk/at.h>
78 #include <netatalk/at_var.h>
79 #endif NETATALK
80 
81 #include "bpfilter.h"
82 
83 static int loioctl __P((struct ifnet *, int, caddr_t));
84 static void lortrequest __P((int, struct rtentry *, struct sockaddr *));
85 
86 static void loopattach __P((void *));
87 PSEUDO_SET(loopattach, if_loop);
88 
89 #ifdef TINY_LOMTU
90 #define	LOMTU	(1024+512)
91 #else
92 #define LOMTU	16384
93 #endif
94 
95 struct	ifnet loif[NLOOP];
96 
97 /* ARGSUSED */
98 static void
99 loopattach(dummy)
100 	void *dummy;
101 {
102 	register struct ifnet *ifp;
103 	register int i = 0;
104 
105 	for (ifp = loif; i < NLOOP; ifp++) {
106 	    ifp->if_name = "lo";
107 	    ifp->if_unit = i++;
108 	    ifp->if_mtu = LOMTU;
109 	    ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
110 	    ifp->if_ioctl = loioctl;
111 	    ifp->if_output = looutput;
112 	    ifp->if_type = IFT_LOOP;
113 	    if_attach(ifp);
114 #if NBPFILTER > 0
115 	    bpfattach(ifp, DLT_NULL, sizeof(u_int));
116 #endif
117 	}
118 }
119 
120 int
121 looutput(ifp, m, dst, rt)
122 	struct ifnet *ifp;
123 	register struct mbuf *m;
124 	struct sockaddr *dst;
125 	register struct rtentry *rt;
126 {
127 	int s, isr;
128 	register struct ifqueue *ifq = 0;
129 
130 	if ((m->m_flags & M_PKTHDR) == 0)
131 		panic("looutput no HDR");
132 #if NBPFILTER > 0
133 	/* BPF write needs to be handled specially */
134 	if (dst->sa_family == AF_UNSPEC) {
135 		dst->sa_family = *(mtod(m, int *));
136 		m->m_len -= sizeof(int);
137 		m->m_pkthdr.len -= sizeof(int);
138 		m->m_data += sizeof(int);
139 	}
140 
141 	if (ifp->if_bpf) {
142 		/*
143 		 * We need to prepend the address family as
144 		 * a four byte field.  Cons up a dummy header
145 		 * to pacify bpf.  This is safe because bpf
146 		 * will only read from the mbuf (i.e., it won't
147 		 * try to free it or keep a pointer a to it).
148 		 */
149 		struct mbuf m0;
150 		u_int af = dst->sa_family;
151 
152 		m0.m_next = m;
153 		m0.m_len = 4;
154 		m0.m_data = (char *)&af;
155 
156 		bpf_mtap(ifp, &m0);
157 	}
158 #endif
159 	m->m_pkthdr.rcvif = ifp;
160 
161 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
162 		m_freem(m);
163 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
164 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
165 	}
166 	ifp->if_opackets++;
167 	ifp->if_obytes += m->m_pkthdr.len;
168 	switch (dst->sa_family) {
169 
170 #ifdef INET
171 	case AF_INET:
172 		ifq = &ipintrq;
173 		isr = NETISR_IP;
174 		break;
175 #endif
176 #ifdef IPX
177 	case AF_IPX:
178 		ifq = &ipxintrq;
179 		isr = NETISR_IPX;
180 		break;
181 #endif
182 #ifdef NS
183 	case AF_NS:
184 		ifq = &nsintrq;
185 		isr = NETISR_NS;
186 		break;
187 #endif
188 #ifdef ISO
189 	case AF_ISO:
190 		ifq = &clnlintrq;
191 		isr = NETISR_ISO;
192 		break;
193 #endif
194 #ifdef NETATALK
195 	case AF_APPLETALK:
196 	        ifq = &atintrq2;
197 		isr = NETISR_ATALK;
198 		break;
199 #endif NETATALK
200 	default:
201 		printf("lo%d: can't handle af%d\n", ifp->if_unit,
202 			dst->sa_family);
203 		m_freem(m);
204 		return (EAFNOSUPPORT);
205 	}
206 	s = splimp();
207 	if (IF_QFULL(ifq)) {
208 		IF_DROP(ifq);
209 		m_freem(m);
210 		splx(s);
211 		return (ENOBUFS);
212 	}
213 	IF_ENQUEUE(ifq, m);
214 	schednetisr(isr);
215 	ifp->if_ipackets++;
216 	ifp->if_ibytes += m->m_pkthdr.len;
217 	splx(s);
218 	return (0);
219 }
220 
221 /* ARGSUSED */
222 static void
223 lortrequest(cmd, rt, sa)
224 	int cmd;
225 	struct rtentry *rt;
226 	struct sockaddr *sa;
227 {
228 	if (rt) {
229 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
230 		/*
231 		 * For optimal performance, the send and receive buffers
232 		 * should be at least twice the MTU plus a little more for
233 		 * overhead.
234 		 */
235 		rt->rt_rmx.rmx_recvpipe =
236 			rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
237 	}
238 }
239 
240 /*
241  * Process an ioctl request.
242  */
243 /* ARGSUSED */
244 static int
245 loioctl(ifp, cmd, data)
246 	register struct ifnet *ifp;
247 	int cmd;
248 	caddr_t data;
249 {
250 	register struct ifaddr *ifa;
251 	register struct ifreq *ifr = (struct ifreq *)data;
252 	register int error = 0;
253 
254 	switch (cmd) {
255 
256 	case SIOCSIFADDR:
257 		ifp->if_flags |= IFF_UP | IFF_RUNNING;
258 		ifa = (struct ifaddr *)data;
259 		ifa->ifa_rtrequest = lortrequest;
260 		/*
261 		 * Everything else is done at a higher level.
262 		 */
263 		break;
264 
265 	case SIOCADDMULTI:
266 	case SIOCDELMULTI:
267 		if (ifr == 0) {
268 			error = EAFNOSUPPORT;		/* XXX */
269 			break;
270 		}
271 		switch (ifr->ifr_addr.sa_family) {
272 
273 #ifdef INET
274 		case AF_INET:
275 			break;
276 #endif
277 
278 		default:
279 			error = EAFNOSUPPORT;
280 			break;
281 		}
282 		break;
283 
284 	case SIOCSIFMTU:
285 		ifp->if_mtu = ifr->ifr_mtu;
286 		break;
287 
288 	default:
289 		error = EINVAL;
290 	}
291 	return (error);
292 }
293 #endif /* NLOOP > 0 */
294