xref: /freebsd/sys/net/if_loop.c (revision d82e286489da73321a47e329d98a98817b0438b6)
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 1.13 1995/09/22 17:57:48 wollman 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 #include <machine/cpu.h>
52 
53 #include <net/if.h>
54 #include <net/if_types.h>
55 #include <net/netisr.h>
56 #include <net/route.h>
57 #include <net/bpf.h>
58 
59 #ifdef	INET
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/in_var.h>
63 #include <netinet/ip.h>
64 #endif
65 
66 #ifdef IPX
67 #include <netipx/ipx.h>
68 #include <netipx/ipx_if.h>
69 #endif
70 
71 #ifdef NS
72 #include <netns/ns.h>
73 #include <netns/ns_if.h>
74 #endif
75 
76 #ifdef ISO
77 #include <netiso/iso.h>
78 #include <netiso/iso_var.h>
79 #endif
80 
81 #include "bpfilter.h"
82 
83 static void loopattach __P((void *));
84 PSEUDO_SET(loopattach, if_loop);
85 
86 #ifdef TINY_LOMTU
87 #define	LOMTU	(1024+512)
88 #else
89 #define LOMTU	16384
90 #endif
91 
92 struct	ifnet loif[NLOOP];
93 
94 /* ARGSUSED */
95 static void
96 loopattach(udata)
97 	void *udata;
98 {
99 	register struct ifnet *ifp;
100 	register int i = 0;
101 
102 	for (ifp = loif; i < NLOOP; ifp++) {
103 	    ifp->if_name = "lo";
104 	    ifp->if_next = NULL;
105 	    ifp->if_unit = i++;
106 	    ifp->if_mtu = LOMTU;
107 	    ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
108 	    ifp->if_ioctl = loioctl;
109 	    ifp->if_output = looutput;
110 	    ifp->if_type = IFT_LOOP;
111 	    ifp->if_hdrlen = 0;
112 	    ifp->if_addrlen = 0;
113 	    if_attach(ifp);
114 #if NBPFILTER > 0
115 	    bpfattach(&ifp->if_bpf, 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 	ifp->if_lastchange = time;
133 #if NBPFILTER > 0
134 	/* BPF write needs to be handled specially */
135 	if (dst->sa_family == AF_UNSPEC) {
136 		dst->sa_family = *(mtod(m, int *));
137 		m->m_len -= sizeof(int);
138 		m->m_pkthdr.len -= sizeof(int);
139 		m->m_data += sizeof(int);
140 	}
141 
142 	if (ifp->if_bpf) {
143 		/*
144 		 * We need to prepend the address family as
145 		 * a four byte field.  Cons up a dummy header
146 		 * to pacify bpf.  This is safe because bpf
147 		 * will only read from the mbuf (i.e., it won't
148 		 * try to free it or keep a pointer a to it).
149 		 */
150 		struct mbuf m0;
151 		u_int af = dst->sa_family;
152 
153 		m0.m_next = m;
154 		m0.m_len = 4;
155 		m0.m_data = (char *)&af;
156 
157 		bpf_mtap(ifp->if_bpf, &m0);
158 	}
159 #endif
160 	m->m_pkthdr.rcvif = ifp;
161 
162 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
163 		m_freem(m);
164 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
165 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
166 	}
167 	ifp->if_opackets++;
168 	ifp->if_obytes += m->m_pkthdr.len;
169 	switch (dst->sa_family) {
170 
171 #ifdef INET
172 	case AF_INET:
173 		ifq = &ipintrq;
174 		isr = NETISR_IP;
175 		break;
176 #endif
177 #ifdef IPX
178 	case AF_IPX:
179 		ifq = &ipxintrq;
180 		isr = NETISR_IPX;
181 		break;
182 #endif
183 #ifdef NS
184 	case AF_NS:
185 		ifq = &nsintrq;
186 		isr = NETISR_NS;
187 		break;
188 #endif
189 #ifdef ISO
190 	case AF_ISO:
191 		ifq = &clnlintrq;
192 		isr = NETISR_ISO;
193 		break;
194 #endif
195 	default:
196 		printf("lo%d: can't handle af%d\n", ifp->if_unit,
197 			dst->sa_family);
198 		m_freem(m);
199 		return (EAFNOSUPPORT);
200 	}
201 	s = splimp();
202 	if (IF_QFULL(ifq)) {
203 		IF_DROP(ifq);
204 		m_freem(m);
205 		splx(s);
206 		return (ENOBUFS);
207 	}
208 	IF_ENQUEUE(ifq, m);
209 	schednetisr(isr);
210 	ifp->if_ipackets++;
211 	ifp->if_ibytes += m->m_pkthdr.len;
212 	splx(s);
213 	return (0);
214 }
215 
216 /* ARGSUSED */
217 void
218 lortrequest(cmd, rt, sa)
219 	int cmd;
220 	struct rtentry *rt;
221 	struct sockaddr *sa;
222 {
223 
224 	if (rt)
225 		rt->rt_rmx.rmx_mtu = LOMTU;
226 }
227 
228 /*
229  * Process an ioctl request.
230  */
231 /* ARGSUSED */
232 int
233 loioctl(ifp, cmd, data)
234 	register struct ifnet *ifp;
235 	int cmd;
236 	caddr_t data;
237 {
238 	register struct ifaddr *ifa;
239 	register struct ifreq *ifr = (struct ifreq *)data;
240 	register int error = 0;
241 
242 	switch (cmd) {
243 
244 	case SIOCSIFADDR:
245 		ifp->if_flags |= IFF_UP;
246 		ifa = (struct ifaddr *)data;
247 		if (ifa != 0 && ifa->ifa_addr->sa_family == AF_ISO)
248 			ifa->ifa_rtrequest = lortrequest;
249 		/*
250 		 * Everything else is done at a higher level.
251 		 */
252 		break;
253 
254 	case SIOCADDMULTI:
255 	case SIOCDELMULTI:
256 		if (ifr == 0) {
257 			error = EAFNOSUPPORT;		/* XXX */
258 			break;
259 		}
260 		switch (ifr->ifr_addr.sa_family) {
261 
262 #ifdef INET
263 		case AF_INET:
264 			break;
265 #endif
266 
267 		default:
268 			error = EAFNOSUPPORT;
269 			break;
270 		}
271 		break;
272 
273 	case SIOCSIFMTU:
274 		ifp->if_mtu = ifr->ifr_mtu;
275 		break;
276 
277 	default:
278 		error = EINVAL;
279 	}
280 	return (error);
281 }
282 #endif /* NLOOP > 0 */
283