xref: /freebsd/sys/net/if_loop.c (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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 1.36 1998/06/14 23:53:43 julian 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 "opt_atalk.h"
44 #include "opt_inet.h"
45 #include "opt_ipx.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
50 #include <sys/mbuf.h>
51 #include <sys/socket.h>
52 #include <sys/sockio.h>
53 
54 #include <net/if.h>
55 #include <net/if_types.h>
56 #include <net/netisr.h>
57 #include <net/route.h>
58 #include <net/bpf.h>
59 
60 #ifdef	INET
61 #include <netinet/in.h>
62 #include <netinet/in_var.h>
63 #endif
64 
65 #ifdef IPX
66 #include <netipx/ipx.h>
67 #include <netipx/ipx_if.h>
68 #endif
69 
70 #ifdef NS
71 #include <netns/ns.h>
72 #include <netns/ns_if.h>
73 #endif
74 
75 #ifdef ISO
76 #include <netiso/iso.h>
77 #include <netiso/iso_var.h>
78 #endif
79 
80 #ifdef NETATALK
81 #include <netatalk/at.h>
82 #include <netatalk/at_var.h>
83 #endif NETATALK
84 
85 #include "bpfilter.h"
86 #if NBPFILTER > 0
87 #include <net/bpfdesc.h>
88 #endif
89 
90 static int loioctl __P((struct ifnet *, u_long, caddr_t));
91 static void lortrequest __P((int, struct rtentry *, struct sockaddr *));
92 
93 static void loopattach __P((void *));
94 PSEUDO_SET(loopattach, if_loop);
95 
96 static int looutput __P((struct ifnet *ifp,
97 		struct mbuf *m, struct sockaddr *dst, struct rtentry *rt));
98 
99 #ifdef TINY_LOMTU
100 #define	LOMTU	(1024+512)
101 #else
102 #define LOMTU	16384
103 #endif
104 
105 struct	ifnet loif[NLOOP];
106 
107 /* ARGSUSED */
108 static void
109 loopattach(dummy)
110 	void *dummy;
111 {
112 	register struct ifnet *ifp;
113 	register int i = 0;
114 
115 	for (ifp = loif; i < NLOOP; ifp++) {
116 	    ifp->if_name = "lo";
117 	    ifp->if_unit = i++;
118 	    ifp->if_mtu = LOMTU;
119 	    ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
120 	    ifp->if_ioctl = loioctl;
121 	    ifp->if_output = looutput;
122 	    ifp->if_type = IFT_LOOP;
123 	    if_attach(ifp);
124 #if NBPFILTER > 0
125 	    bpfattach(ifp, DLT_NULL, sizeof(u_int));
126 #endif
127 	}
128 }
129 
130 static int
131 looutput(ifp, m, dst, rt)
132 	struct ifnet *ifp;
133 	register struct mbuf *m;
134 	struct sockaddr *dst;
135 	register struct rtentry *rt;
136 {
137 	if ((m->m_flags & M_PKTHDR) == 0)
138 		panic("looutput no HDR");
139 
140 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
141 		m_freem(m);
142 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
143 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
144 	}
145 	ifp->if_opackets++;
146 	ifp->if_obytes += m->m_pkthdr.len;
147 #if 1	/* XXX */
148 	switch (dst->sa_family) {
149 	case AF_INET:
150 	case AF_IPX:
151 	case AF_NS:
152 	case AF_ISO:
153 	case AF_APPLETALK:
154 		break;
155 	default:
156 		printf("looutput: af=%d unexpected", dst->sa_family);
157 		m_freem(m);
158 		return (EAFNOSUPPORT);
159 	}
160 #endif
161 	return(if_simloop(ifp, m, dst, 0));
162 }
163 
164 /*
165  * if_simloop()
166  *
167  * This function is to support software emulation of hardware loopback,
168  * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
169  * hear their own broadcasts, we create a copy of the packet that we
170  * would normally receive via a hardware loopback.
171  *
172  * This function expects the packet to include the media header of length hlen.
173  */
174 
175 int
176 if_simloop(ifp, m, dst, hlen)
177 	struct ifnet *ifp;
178 	register struct mbuf *m;
179 	struct sockaddr *dst;
180 	int hlen;
181 {
182 	int s, isr;
183 	register struct ifqueue *ifq = 0;
184 
185 	if ((m->m_flags & M_PKTHDR) == 0)
186 		panic("if_simloop: no HDR");
187 	m->m_pkthdr.rcvif = ifp;
188 #if NBPFILTER > 0
189 	/* BPF write needs to be handled specially */
190 	if (dst->sa_family == AF_UNSPEC) {
191 		dst->sa_family = *(mtod(m, int *));
192 		m->m_len -= sizeof(int);
193 		m->m_pkthdr.len -= sizeof(int);
194 		m->m_data += sizeof(int);
195 	}
196 
197 	if (ifp->if_bpf) {
198 		struct mbuf m0, *n = m;
199 		u_int af = dst->sa_family;
200 
201 		if (ifp->if_bpf->bif_dlt == DLT_NULL) {
202 			/*
203 			 * We need to prepend the address family as
204 			 * a four byte field.  Cons up a dummy header
205 			 * to pacify bpf.  This is safe because bpf
206 			 * will only read from the mbuf (i.e., it won't
207 			 * try to free it or keep a pointer a to it).
208 			 */
209 			m0.m_next = m;
210 			m0.m_len = 4;
211 			m0.m_data = (char *)&af;
212 			n = &m0;
213 		}
214 		bpf_mtap(ifp, n);
215 	}
216 #endif
217 
218 	/* Strip away media header */
219 	if (hlen > 0) {
220 #ifdef __alpha__
221 		/* The alpha doesn't like unaligned data.
222 		 * We move data down in the first mbuf */
223 		if (hlen & 3) {
224 			bcopy(m->m_data + hlen, m->m_data, m->m_len - hlen);
225 			m->m_len -= hlen;
226 			if (m->m_flags & M_PKTHDR)
227 				m->m_pkthdr.len -= hlen;
228 		} else
229 #endif
230 		m_adj(m, hlen);
231 	}
232 
233 	switch (dst->sa_family) {
234 #ifdef INET
235 	case AF_INET:
236 		ifq = &ipintrq;
237 		isr = NETISR_IP;
238 		break;
239 #endif
240 #ifdef IPX
241 	case AF_IPX:
242 		ifq = &ipxintrq;
243 		isr = NETISR_IPX;
244 		break;
245 #endif
246 #ifdef NS
247 	case AF_NS:
248 		ifq = &nsintrq;
249 		isr = NETISR_NS;
250 		break;
251 #endif
252 #ifdef ISO
253 	case AF_ISO:
254 		ifq = &clnlintrq;
255 		isr = NETISR_ISO;
256 		break;
257 #endif
258 #ifdef NETATALK
259 	case AF_APPLETALK:
260 	        ifq = &atintrq2;
261 		isr = NETISR_ATALK;
262 		break;
263 #endif NETATALK
264 	default:
265 		printf("if_simloop: can't handle af=%d\n", dst->sa_family);
266 		m_freem(m);
267 		return (EAFNOSUPPORT);
268 	}
269 	s = splimp();
270 	if (IF_QFULL(ifq)) {
271 		IF_DROP(ifq);
272 		m_freem(m);
273 		splx(s);
274 		return (ENOBUFS);
275 	}
276 	IF_ENQUEUE(ifq, m);
277 	schednetisr(isr);
278 	ifp->if_ipackets++;
279 	ifp->if_ibytes += m->m_pkthdr.len;
280 	splx(s);
281 	return (0);
282 }
283 
284 /* ARGSUSED */
285 static void
286 lortrequest(cmd, rt, sa)
287 	int cmd;
288 	struct rtentry *rt;
289 	struct sockaddr *sa;
290 {
291 	if (rt) {
292 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
293 		/*
294 		 * For optimal performance, the send and receive buffers
295 		 * should be at least twice the MTU plus a little more for
296 		 * overhead.
297 		 */
298 		rt->rt_rmx.rmx_recvpipe =
299 			rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
300 	}
301 }
302 
303 /*
304  * Process an ioctl request.
305  */
306 /* ARGSUSED */
307 static int
308 loioctl(ifp, cmd, data)
309 	register struct ifnet *ifp;
310 	u_long cmd;
311 	caddr_t data;
312 {
313 	register struct ifaddr *ifa;
314 	register struct ifreq *ifr = (struct ifreq *)data;
315 	register int error = 0;
316 
317 	switch (cmd) {
318 
319 	case SIOCSIFADDR:
320 		ifp->if_flags |= IFF_UP | IFF_RUNNING;
321 		ifa = (struct ifaddr *)data;
322 		ifa->ifa_rtrequest = lortrequest;
323 		/*
324 		 * Everything else is done at a higher level.
325 		 */
326 		break;
327 
328 	case SIOCADDMULTI:
329 	case SIOCDELMULTI:
330 		if (ifr == 0) {
331 			error = EAFNOSUPPORT;		/* XXX */
332 			break;
333 		}
334 		switch (ifr->ifr_addr.sa_family) {
335 
336 #ifdef INET
337 		case AF_INET:
338 			break;
339 #endif
340 
341 		default:
342 			error = EAFNOSUPPORT;
343 			break;
344 		}
345 		break;
346 
347 	case SIOCSIFMTU:
348 		ifp->if_mtu = ifr->ifr_mtu;
349 		break;
350 
351 	case SIOCSIFFLAGS:
352 		break;
353 
354 	default:
355 		error = EINVAL;
356 	}
357 	return (error);
358 }
359 #endif /* NLOOP > 0 */
360