xref: /freebsd/sys/net/if_loop.c (revision df8bae1de4b67ccf57f4afebd4e2bf258c38910d)
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  */
35 
36 /*
37  * Loopback interface driver for protocol testing and timing.
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/mbuf.h>
44 #include <sys/socket.h>
45 #include <sys/errno.h>
46 #include <sys/ioctl.h>
47 #include <sys/time.h>
48 #include <machine/cpu.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_systm.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip.h>
61 #endif
62 
63 #ifdef NS
64 #include <netns/ns.h>
65 #include <netns/ns_if.h>
66 #endif
67 
68 #ifdef ISO
69 #include <netiso/iso.h>
70 #include <netiso/iso_var.h>
71 #endif
72 
73 #include "bpfilter.h"
74 
75 #define	LOMTU	(1024+512)
76 
77 struct	ifnet loif;
78 
79 /* ARGSUSED */
80 void
81 loopattach(n)
82 	int n;
83 {
84 	register struct ifnet *ifp = &loif;
85 
86 #ifdef lint
87 	n = n;			/* Highlander: there can only be one... */
88 #endif
89 	ifp->if_name = "lo";
90 	ifp->if_mtu = LOMTU;
91 	ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
92 	ifp->if_ioctl = loioctl;
93 	ifp->if_output = looutput;
94 	ifp->if_type = IFT_LOOP;
95 	ifp->if_hdrlen = 0;
96 	ifp->if_addrlen = 0;
97 	if_attach(ifp);
98 #if NBPFILTER > 0
99 	bpfattach(&ifp->if_bpf, ifp, DLT_NULL, sizeof(u_int));
100 #endif
101 }
102 
103 int
104 looutput(ifp, m, dst, rt)
105 	struct ifnet *ifp;
106 	register struct mbuf *m;
107 	struct sockaddr *dst;
108 	register struct rtentry *rt;
109 {
110 	int s, isr;
111 	register struct ifqueue *ifq = 0;
112 
113 	if ((m->m_flags & M_PKTHDR) == 0)
114 		panic("looutput no HDR");
115 	ifp->if_lastchange = time;
116 #if NBPFILTER > 0
117 	if (loif.if_bpf) {
118 		/*
119 		 * We need to prepend the address family as
120 		 * a four byte field.  Cons up a dummy header
121 		 * to pacify bpf.  This is safe because bpf
122 		 * will only read from the mbuf (i.e., it won't
123 		 * try to free it or keep a pointer a to it).
124 		 */
125 		struct mbuf m0;
126 		u_int af = dst->sa_family;
127 
128 		m0.m_next = m;
129 		m0.m_len = 4;
130 		m0.m_data = (char *)&af;
131 
132 		bpf_mtap(loif.if_bpf, &m0);
133 	}
134 #endif
135 	m->m_pkthdr.rcvif = ifp;
136 
137 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
138 		m_freem(m);
139 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
140 		        rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
141 	}
142 	ifp->if_opackets++;
143 	ifp->if_obytes += m->m_pkthdr.len;
144 	switch (dst->sa_family) {
145 
146 #ifdef INET
147 	case AF_INET:
148 		ifq = &ipintrq;
149 		isr = NETISR_IP;
150 		break;
151 #endif
152 #ifdef NS
153 	case AF_NS:
154 		ifq = &nsintrq;
155 		isr = NETISR_NS;
156 		break;
157 #endif
158 #ifdef ISO
159 	case AF_ISO:
160 		ifq = &clnlintrq;
161 		isr = NETISR_ISO;
162 		break;
163 #endif
164 	default:
165 		printf("lo%d: can't handle af%d\n", ifp->if_unit,
166 			dst->sa_family);
167 		m_freem(m);
168 		return (EAFNOSUPPORT);
169 	}
170 	s = splimp();
171 	if (IF_QFULL(ifq)) {
172 		IF_DROP(ifq);
173 		m_freem(m);
174 		splx(s);
175 		return (ENOBUFS);
176 	}
177 	IF_ENQUEUE(ifq, m);
178 	schednetisr(isr);
179 	ifp->if_ipackets++;
180 	ifp->if_ibytes += m->m_pkthdr.len;
181 	splx(s);
182 	return (0);
183 }
184 
185 /* ARGSUSED */
186 void
187 lortrequest(cmd, rt, sa)
188 	int cmd;
189 	struct rtentry *rt;
190 	struct sockaddr *sa;
191 {
192 
193 	if (rt)
194 		rt->rt_rmx.rmx_mtu = LOMTU;
195 }
196 
197 /*
198  * Process an ioctl request.
199  */
200 /* ARGSUSED */
201 int
202 loioctl(ifp, cmd, data)
203 	register struct ifnet *ifp;
204 	int cmd;
205 	caddr_t data;
206 {
207 	register struct ifaddr *ifa;
208 	register struct ifreq *ifr;
209 	register int error = 0;
210 
211 	switch (cmd) {
212 
213 	case SIOCSIFADDR:
214 		ifp->if_flags |= IFF_UP;
215 		ifa = (struct ifaddr *)data;
216 		if (ifa != 0 && ifa->ifa_addr->sa_family == AF_ISO)
217 			ifa->ifa_rtrequest = lortrequest;
218 		/*
219 		 * Everything else is done at a higher level.
220 		 */
221 		break;
222 
223 	case SIOCADDMULTI:
224 	case SIOCDELMULTI:
225 		ifr = (struct ifreq *)data;
226 		if (ifr == 0) {
227 			error = EAFNOSUPPORT;		/* XXX */
228 			break;
229 		}
230 		switch (ifr->ifr_addr.sa_family) {
231 
232 #ifdef INET
233 		case AF_INET:
234 			break;
235 #endif
236 
237 		default:
238 			error = EAFNOSUPPORT;
239 			break;
240 		}
241 		break;
242 
243 	default:
244 		error = EINVAL;
245 	}
246 	return (error);
247 }
248