2 * Copyright (c) 1982, 1986, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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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
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18 * may be used to endorse or promote products derived from this software
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33 * @(#)if_loop.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $
35 * $DragonFly: src/sys/net/if_loop.c,v 1.26 2008/10/04 11:21:10 sephe Exp $
39 * Loopback interface driver for protocol testing and timing.
43 #include "opt_atalk.h"
45 #include "opt_inet6.h"
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
53 #include <sys/socket.h>
54 #include <sys/sockio.h>
57 #include <net/if_types.h>
58 #include <net/ifq_var.h>
59 #include <net/netisr.h>
60 #include <net/route.h>
62 #include <net/bpfdesc.h>
65 #include <netinet/in.h>
66 #include <netinet/in_var.h>
70 #include <netproto/ipx/ipx.h>
71 #include <netproto/ipx/ipx_if.h>
76 #include <netinet/in.h>
78 #include <netinet6/in6_var.h>
79 #include <netinet/ip6.h>
84 #include <netns/ns_if.h>
88 #include <netproto/atalk/at.h>
89 #include <netproto/atalk/at_var.h>
92 static void loopattach(void *);
93 static int looutput(struct ifnet
*, struct mbuf
*, struct sockaddr
*,
95 static int loioctl(struct ifnet
*, u_long
, caddr_t
, struct ucred
*);
96 static void lortrequest(int, struct rtentry
*, struct rt_addrinfo
*);
98 static void lo_altqstart(struct ifnet
*);
100 PSEUDO_SET(loopattach
, if_loop
);
103 #define LOMTU (1024+512)
104 #elif defined(LARGE_LOMTU)
110 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_UDP | CSUM_TCP)
112 struct ifnet loif
[NLOOP
];
116 loopattach(void *dummy
)
121 for (i
= 0, ifp
= loif
; i
< NLOOP
; i
++, ifp
++) {
122 if_initname(ifp
, "lo", i
);
124 ifp
->if_flags
= IFF_LOOPBACK
| IFF_MULTICAST
;
125 ifp
->if_capabilities
= IFCAP_HWCSUM
;
126 ifp
->if_hwassist
= LO_CSUM_FEATURES
;
127 ifp
->if_capenable
= ifp
->if_capabilities
;
128 ifp
->if_ioctl
= loioctl
;
129 ifp
->if_output
= looutput
;
130 ifp
->if_type
= IFT_LOOP
;
131 ifq_set_maxlen(&ifp
->if_snd
, ifqmaxlen
);
132 ifq_set_ready(&ifp
->if_snd
);
134 ifp
->if_start
= lo_altqstart
;
136 if_attach(ifp
, NULL
);
137 bpfattach(ifp
, DLT_NULL
, sizeof(u_int
));
142 looutput(struct ifnet
*ifp
, struct mbuf
*m
, struct sockaddr
*dst
,
147 if (rt
&& rt
->rt_flags
& (RTF_REJECT
|RTF_BLACKHOLE
)) {
149 return (rt
->rt_flags
& RTF_BLACKHOLE
? 0 :
150 rt
->rt_flags
& RTF_HOST
? EHOSTUNREACH
: ENETUNREACH
);
154 ifp
->if_obytes
+= m
->m_pkthdr
.len
;
156 switch (dst
->sa_family
) {
164 kprintf("looutput: af=%d unexpected\n", dst
->sa_family
);
166 return (EAFNOSUPPORT
);
170 if (ifp
->if_capenable
& IFCAP_RXCSUM
) {
173 if (m
->m_pkthdr
.csum_flags
& CSUM_IP
)
174 csum_flags
|= (CSUM_IP_CHECKED
| CSUM_IP_VALID
);
175 if (m
->m_pkthdr
.csum_flags
& CSUM_DELAY_DATA
)
176 csum_flags
|= (CSUM_DATA_VALID
| CSUM_PSEUDO_HDR
);
178 m
->m_pkthdr
.csum_flags
|= csum_flags
;
179 if (csum_flags
& CSUM_DATA_VALID
)
180 m
->m_pkthdr
.csum_data
= 0xffff;
182 return (if_simloop(ifp
, m
, dst
->sa_family
, 0));
188 * This function is to support software emulation of hardware loopback,
189 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
190 * hear their own broadcasts, we create a copy of the packet that we
191 * would normally receive via a hardware loopback.
193 * This function expects the packet to include the media header of length hlen.
196 if_simloop(struct ifnet
*ifp
, struct mbuf
*m
, int af
, int hlen
)
200 KASSERT((m
->m_flags
& M_PKTHDR
) != 0, ("if_simloop: no HDR"));
201 m
->m_pkthdr
.rcvif
= ifp
;
203 /* BPF write needs to be handled specially */
204 if (af
== AF_UNSPEC
) {
205 KASSERT(m
->m_len
>= sizeof(int), ("if_simloop: m_len"));
206 af
= *(mtod(m
, int *));
207 m
->m_len
-= sizeof(int);
208 m
->m_pkthdr
.len
-= sizeof(int);
209 m
->m_data
+= sizeof(int);
216 if (ifp
->if_bpf
== NULL
)
219 if (ifp
->if_bpf
->bif_dlt
== DLT_NULL
) {
220 uint32_t bpf_af
= (uint32_t)af
;
221 bpf_ptap(ifp
->if_bpf
, m
, &bpf_af
, 4);
223 bpf_mtap(ifp
->if_bpf
, m
);
229 /* Strip away media header */
235 * altq for loop is just for debugging.
236 * only used when called for loop interface (not for
237 * a simplex interface).
239 if (ifq_is_enabled(&ifp
->if_snd
) && ifp
->if_start
== lo_altqstart
) {
240 struct altq_pktattr pktattr
;
245 * if the queueing discipline needs packet classification,
246 * do it before prepending link headers.
248 ifq_classify(&ifp
->if_snd
, m
, af
, &pktattr
);
250 M_PREPEND(m
, sizeof(int32_t), MB_DONTWAIT
);
253 afp
= mtod(m
, int32_t *);
257 * A critical section is needed for subsystems protected by
258 * the MP lock, and the serializer is assumed to already
259 * be held for MPSAFE subsystems.
262 error
= ifq_enqueue(&ifp
->if_snd
, m
, &pktattr
);
263 ifnet_serialize_tx(ifp
);
265 ifnet_deserialize_tx(ifp
);
271 /* Deliver to upper layer protocol */
280 m
->m_flags
|= M_LOOP
;
300 kprintf("if_simloop: can't handle af=%d\n", af
);
302 return (EAFNOSUPPORT
);
306 ifp
->if_ibytes
+= m
->m_pkthdr
.len
;
307 netisr_queue(isr
, m
);
313 lo_altqstart(struct ifnet
*ifp
)
321 m
= ifq_dequeue(&ifp
->if_snd
, NULL
);
326 afp
= mtod(m
, int32_t *);
328 m_adj(m
, sizeof(int32_t));
338 m
->m_flags
|= M_LOOP
;
363 kprintf("lo_altqstart: can't handle af%d\n", af
);
369 ifp
->if_ibytes
+= m
->m_pkthdr
.len
;
370 netisr_queue(isr
, m
);
377 lortrequest(int cmd
, struct rtentry
*rt
, struct rt_addrinfo
*info
)
380 rt
->rt_rmx
.rmx_mtu
= rt
->rt_ifp
->if_mtu
; /* for ISO */
382 * For optimal performance, the send and receive buffers
383 * should be at least twice the MTU plus a little more for
386 rt
->rt_rmx
.rmx_recvpipe
= rt
->rt_rmx
.rmx_sendpipe
= 3 * LOMTU
;
391 * Process an ioctl request.
395 loioctl(struct ifnet
*ifp
, u_long cmd
, caddr_t data
, struct ucred
*cr
)
398 struct ifreq
*ifr
= (struct ifreq
*)data
;
403 ifp
->if_flags
|= IFF_UP
| IFF_RUNNING
;
404 ifa
= (struct ifaddr
*)data
;
405 ifa
->ifa_rtrequest
= lortrequest
;
407 * Everything else is done at a higher level.
414 error
= EAFNOSUPPORT
; /* XXX */
417 switch (ifr
->ifr_addr
.sa_family
) {
429 error
= EAFNOSUPPORT
;
435 ifp
->if_mtu
= ifr
->ifr_mtu
;
442 mask
= (ifr
->ifr_reqcap
^ ifp
->if_capenable
) & IFCAP_HWCSUM
;
444 ifp
->if_capenable
^= mask
;
445 if (IFCAP_TXCSUM
& ifp
->if_capenable
)
446 ifp
->if_hwassist
= LO_CSUM_FEATURES
;
448 ifp
->if_hwassist
= 0;