xref: /freebsd/sys/net/if_loop.c (revision 9ee40678bbdcedc6a3ac1e311abe740018911cf1)
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 1.21 1996/06/10 23:07:31 gpalmer 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/errno.h>
49 #include <sys/ioctl.h>
50 #include <sys/time.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 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 <netinet/if_ether.h>
82 #include <netatalk/at.h>
83 #include <netatalk/at_var.h>
84 #endif NETATALK
85 
86 #include "bpfilter.h"
87 
88 static int loioctl __P((struct ifnet *, int, caddr_t));
89 static void lortrequest __P((int, struct rtentry *, struct sockaddr *));
90 
91 static void loopattach __P((void *));
92 PSEUDO_SET(loopattach, if_loop);
93 
94 #ifdef TINY_LOMTU
95 #define	LOMTU	(1024+512)
96 #else
97 #define LOMTU	16384
98 #endif
99 
100 struct	ifnet loif[NLOOP];
101 
102 /* ARGSUSED */
103 static void
104 loopattach(dummy)
105 	void *dummy;
106 {
107 	register struct ifnet *ifp;
108 	register int i = 0;
109 
110 	for (ifp = loif; i < NLOOP; ifp++) {
111 	    ifp->if_name = "lo";
112 	    ifp->if_next = NULL;
113 	    ifp->if_unit = i++;
114 	    ifp->if_mtu = LOMTU;
115 	    ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
116 	    ifp->if_ioctl = loioctl;
117 	    ifp->if_output = looutput;
118 	    ifp->if_type = IFT_LOOP;
119 	    ifp->if_hdrlen = 0;
120 	    ifp->if_addrlen = 0;
121 	    if_attach(ifp);
122 #if NBPFILTER > 0
123 	    bpfattach(ifp, DLT_NULL, sizeof(u_int));
124 #endif
125 	}
126 }
127 
128 int
129 looutput(ifp, m, dst, rt)
130 	struct ifnet *ifp;
131 	register struct mbuf *m;
132 	struct sockaddr *dst;
133 	register struct rtentry *rt;
134 {
135 	int s, isr;
136 	register struct ifqueue *ifq = 0;
137 
138 	if ((m->m_flags & M_PKTHDR) == 0)
139 		panic("looutput no HDR");
140 #if NBPFILTER > 0
141 	/* BPF write needs to be handled specially */
142 	if (dst->sa_family == AF_UNSPEC) {
143 		dst->sa_family = *(mtod(m, int *));
144 		m->m_len -= sizeof(int);
145 		m->m_pkthdr.len -= sizeof(int);
146 		m->m_data += sizeof(int);
147 	}
148 
149 	if (ifp->if_bpf) {
150 		/*
151 		 * We need to prepend the address family as
152 		 * a four byte field.  Cons up a dummy header
153 		 * to pacify bpf.  This is safe because bpf
154 		 * will only read from the mbuf (i.e., it won't
155 		 * try to free it or keep a pointer a to it).
156 		 */
157 		struct mbuf m0;
158 		u_int af = dst->sa_family;
159 
160 		m0.m_next = m;
161 		m0.m_len = 4;
162 		m0.m_data = (char *)&af;
163 
164 		bpf_mtap(ifp, &m0);
165 	}
166 #endif
167 	m->m_pkthdr.rcvif = ifp;
168 
169 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
170 		m_freem(m);
171 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
172 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
173 	}
174 	ifp->if_opackets++;
175 	ifp->if_obytes += m->m_pkthdr.len;
176 	switch (dst->sa_family) {
177 
178 #ifdef INET
179 	case AF_INET:
180 		ifq = &ipintrq;
181 		isr = NETISR_IP;
182 		break;
183 #endif
184 #ifdef IPX
185 	case AF_IPX:
186 		ifq = &ipxintrq;
187 		isr = NETISR_IPX;
188 		break;
189 #endif
190 #ifdef NS
191 	case AF_NS:
192 		ifq = &nsintrq;
193 		isr = NETISR_NS;
194 		break;
195 #endif
196 #ifdef ISO
197 	case AF_ISO:
198 		ifq = &clnlintrq;
199 		isr = NETISR_ISO;
200 		break;
201 #endif
202 #ifdef NETATALK
203 	case AF_APPLETALK:
204 	        ifq = &atintrq2;
205 		isr = NETISR_ATALK;
206 		break;
207 #endif NETATALK
208 	default:
209 		printf("lo%d: can't handle af%d\n", ifp->if_unit,
210 			dst->sa_family);
211 		m_freem(m);
212 		return (EAFNOSUPPORT);
213 	}
214 	s = splimp();
215 	if (IF_QFULL(ifq)) {
216 		IF_DROP(ifq);
217 		m_freem(m);
218 		splx(s);
219 		return (ENOBUFS);
220 	}
221 	IF_ENQUEUE(ifq, m);
222 	schednetisr(isr);
223 	ifp->if_ipackets++;
224 	ifp->if_ibytes += m->m_pkthdr.len;
225 	splx(s);
226 	return (0);
227 }
228 
229 /* ARGSUSED */
230 static void
231 lortrequest(cmd, rt, sa)
232 	int cmd;
233 	struct rtentry *rt;
234 	struct sockaddr *sa;
235 {
236 	if (rt) {
237 		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
238 		/*
239 		 * For optimal performance, the send and receive buffers
240 		 * should be at least twice the MTU plus a little more for
241 		 * overhead.
242 		 */
243 		rt->rt_rmx.rmx_recvpipe =
244 			rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
245 	}
246 }
247 
248 /*
249  * Process an ioctl request.
250  */
251 /* ARGSUSED */
252 static int
253 loioctl(ifp, cmd, data)
254 	register struct ifnet *ifp;
255 	int cmd;
256 	caddr_t data;
257 {
258 	register struct ifaddr *ifa;
259 	register struct ifreq *ifr = (struct ifreq *)data;
260 	register int error = 0;
261 
262 	switch (cmd) {
263 
264 	case SIOCSIFADDR:
265 		ifp->if_flags |= IFF_UP | IFF_RUNNING;
266 		ifa = (struct ifaddr *)data;
267 		ifa->ifa_rtrequest = lortrequest;
268 		/*
269 		 * Everything else is done at a higher level.
270 		 */
271 		break;
272 
273 	case SIOCADDMULTI:
274 	case SIOCDELMULTI:
275 		if (ifr == 0) {
276 			error = EAFNOSUPPORT;		/* XXX */
277 			break;
278 		}
279 		switch (ifr->ifr_addr.sa_family) {
280 
281 #ifdef INET
282 		case AF_INET:
283 			break;
284 #endif
285 
286 		default:
287 			error = EAFNOSUPPORT;
288 			break;
289 		}
290 		break;
291 
292 	case SIOCSIFMTU:
293 		ifp->if_mtu = ifr->ifr_mtu;
294 		break;
295 
296 	default:
297 		error = EINVAL;
298 	}
299 	return (error);
300 }
301 #endif /* NLOOP > 0 */
302