xref: /freebsd/sys/net/if_loop.c (revision 0c43d89a0d8e976ca494d4837f4c1f3734d2c300)
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 1.5 1994/08/02 07:46:17 davidg Exp $
35  */
36 
37 /*
38  * Loopback interface driver for protocol testing and timing.
39  */
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/mbuf.h>
45 #include <sys/socket.h>
46 #include <sys/errno.h>
47 #include <sys/ioctl.h>
48 #include <sys/time.h>
49 #include <machine/cpu.h>
50 
51 #include <net/if.h>
52 #include <net/if_types.h>
53 #include <net/netisr.h>
54 #include <net/route.h>
55 #include <net/bpf.h>
56 
57 #ifdef	INET
58 #include <netinet/in.h>
59 #include <netinet/in_systm.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip.h>
62 #endif
63 
64 #ifdef NS
65 #include <netns/ns.h>
66 #include <netns/ns_if.h>
67 #endif
68 
69 #ifdef ISO
70 #include <netiso/iso.h>
71 #include <netiso/iso_var.h>
72 #endif
73 
74 #include "bpfilter.h"
75 
76 #ifdef TINY_LOMTU
77 #define	LOMTU	(1024+512)
78 #else
79 #define LOMTU	65532
80 #endif
81 
82 struct	ifnet loif;
83 
84 /* ARGSUSED */
85 void
86 loopattach(void)
87 {
88 	register struct ifnet *ifp = &loif;
89 
90 	ifp->if_name = "lo";
91 	ifp->if_mtu = LOMTU;
92 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
93 	ifp->if_ioctl = loioctl;
94 	ifp->if_output = looutput;
95 	ifp->if_type = IFT_LOOP;
96 	ifp->if_hdrlen = 0;
97 	ifp->if_addrlen = 0;
98 	if_attach(ifp);
99 #if NBPFILTER > 0
100 	bpfattach(&ifp->if_bpf, ifp, DLT_NULL, sizeof(u_int));
101 #endif
102 }
103 
104 TEXT_SET(pseudo_set, loopattach);
105 
106 int
107 looutput(ifp, m, dst, rt)
108 	struct ifnet *ifp;
109 	register struct mbuf *m;
110 	struct sockaddr *dst;
111 	register struct rtentry *rt;
112 {
113 	int s, isr;
114 	register struct ifqueue *ifq = 0;
115 
116 	if ((m->m_flags & M_PKTHDR) == 0)
117 		panic("looutput no HDR");
118 	ifp->if_lastchange = time;
119 #if NBPFILTER > 0
120 	if (loif.if_bpf) {
121 		/*
122 		 * We need to prepend the address family as
123 		 * a four byte field.  Cons up a dummy header
124 		 * to pacify bpf.  This is safe because bpf
125 		 * will only read from the mbuf (i.e., it won't
126 		 * try to free it or keep a pointer a to it).
127 		 */
128 		struct mbuf m0;
129 		u_int af = dst->sa_family;
130 
131 		m0.m_next = m;
132 		m0.m_len = 4;
133 		m0.m_data = (char *)&af;
134 
135 		bpf_mtap(loif.if_bpf, &m0);
136 	}
137 #endif
138 	m->m_pkthdr.rcvif = ifp;
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 	switch (dst->sa_family) {
148 
149 #ifdef INET
150 	case AF_INET:
151 		ifq = &ipintrq;
152 		isr = NETISR_IP;
153 		break;
154 #endif
155 #ifdef NS
156 	case AF_NS:
157 		ifq = &nsintrq;
158 		isr = NETISR_NS;
159 		break;
160 #endif
161 #ifdef ISO
162 	case AF_ISO:
163 		ifq = &clnlintrq;
164 		isr = NETISR_ISO;
165 		break;
166 #endif
167 	default:
168 		printf("lo%d: can't handle af%d\n", ifp->if_unit,
169 			dst->sa_family);
170 		m_freem(m);
171 		return (EAFNOSUPPORT);
172 	}
173 	s = splimp();
174 	if (IF_QFULL(ifq)) {
175 		IF_DROP(ifq);
176 		m_freem(m);
177 		splx(s);
178 		return (ENOBUFS);
179 	}
180 	IF_ENQUEUE(ifq, m);
181 	schednetisr(isr);
182 	ifp->if_ipackets++;
183 	ifp->if_ibytes += m->m_pkthdr.len;
184 	splx(s);
185 	return (0);
186 }
187 
188 /* ARGSUSED */
189 void
190 lortrequest(cmd, rt, sa)
191 	int cmd;
192 	struct rtentry *rt;
193 	struct sockaddr *sa;
194 {
195 
196 	if (rt)
197 		rt->rt_rmx.rmx_mtu = LOMTU;
198 }
199 
200 /*
201  * Process an ioctl request.
202  */
203 /* ARGSUSED */
204 int
205 loioctl(ifp, cmd, data)
206 	register struct ifnet *ifp;
207 	int cmd;
208 	caddr_t data;
209 {
210 	register struct ifaddr *ifa;
211 	register struct ifreq *ifr = (struct ifreq *)data;
212 	register int error = 0;
213 
214 	switch (cmd) {
215 
216 	case SIOCSIFADDR:
217 		ifp->if_flags |= IFF_UP;
218 		ifa = (struct ifaddr *)data;
219 		if (ifa != 0 && ifa->ifa_addr->sa_family == AF_ISO)
220 			ifa->ifa_rtrequest = lortrequest;
221 		/*
222 		 * Everything else is done at a higher level.
223 		 */
224 		break;
225 
226 	case SIOCADDMULTI:
227 	case SIOCDELMULTI:
228 		if (ifr == 0) {
229 			error = EAFNOSUPPORT;		/* XXX */
230 			break;
231 		}
232 		switch (ifr->ifr_addr.sa_family) {
233 
234 #ifdef INET
235 		case AF_INET:
236 			break;
237 #endif
238 
239 		default:
240 			error = EAFNOSUPPORT;
241 			break;
242 		}
243 		break;
244 
245 	case SIOCSIFMTU:
246 		ifp->if_mtu = ifr->ifr_mtu;
247 		break;
248 
249 	default:
250 		error = EINVAL;
251 	}
252 	return (error);
253 }
254