2 * Copyright (c) 1982, 1986, 1993
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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29 * @(#)if_loop.c 8.1 (Berkeley) 6/10/93
30 * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $
34 * Loopback interface driver for protocol testing and timing.
39 #include "opt_inet6.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
46 #include <sys/socket.h>
47 #include <sys/sockio.h>
49 #include <sys/mplock2.h>
52 #include <net/if_types.h>
53 #include <net/ifq_var.h>
54 #include <net/netisr.h>
55 #include <net/route.h>
57 #include <net/bpfdesc.h>
60 #include <netinet/in.h>
61 #include <netinet/in_var.h>
66 #include <netinet/in.h>
68 #include <netinet6/in6_var.h>
69 #include <netinet/ip6.h>
72 static void loopattach(void *);
73 static int looutput(struct ifnet
*, struct mbuf
*, struct sockaddr
*,
75 static int loioctl(struct ifnet
*, u_long
, caddr_t
, struct ucred
*);
76 static void lortrequest(int, struct rtentry
*);
78 static void lo_altqstart(struct ifnet
*, struct ifaltq_subque
*);
80 PSEUDO_SET(loopattach
, if_loop
);
83 #define LOMTU (1024+512)
84 #elif defined(LARGE_LOMTU)
90 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_UDP | CSUM_TCP)
92 struct ifnet loif
[NLOOP
];
96 loopattach(void *dummy
)
101 for (i
= 0, ifp
= loif
; i
< NLOOP
; i
++, ifp
++) {
102 if_initname(ifp
, "lo", i
);
104 ifp
->if_flags
= IFF_LOOPBACK
| IFF_MULTICAST
;
105 ifp
->if_capabilities
= IFCAP_HWCSUM
| IFCAP_RSS
;
106 ifp
->if_hwassist
= LO_CSUM_FEATURES
;
107 ifp
->if_capenable
= ifp
->if_capabilities
;
108 ifp
->if_ioctl
= loioctl
;
109 ifp
->if_output
= looutput
;
110 ifp
->if_type
= IFT_LOOP
;
111 ifq_set_maxlen(&ifp
->if_snd
, ifqmaxlen
);
112 ifq_set_ready(&ifp
->if_snd
);
114 ifp
->if_start
= lo_altqstart
;
116 if_attach(ifp
, NULL
);
117 bpfattach(ifp
, DLT_NULL
, sizeof(u_int
));
122 looutput(struct ifnet
*ifp
, struct mbuf
*m
, struct sockaddr
*dst
,
127 if (rt
&& rt
->rt_flags
& (RTF_REJECT
|RTF_BLACKHOLE
)) {
129 return (rt
->rt_flags
& RTF_BLACKHOLE
? 0 :
130 rt
->rt_flags
& RTF_HOST
? EHOSTUNREACH
: ENETUNREACH
);
133 IFNET_STAT_INC(ifp
, opackets
, 1);
134 IFNET_STAT_INC(ifp
, obytes
, m
->m_pkthdr
.len
);
136 switch (dst
->sa_family
) {
141 kprintf("looutput: af=%d unexpected\n", dst
->sa_family
);
143 return (EAFNOSUPPORT
);
147 if (ifp
->if_capenable
& IFCAP_RXCSUM
) {
150 if (m
->m_pkthdr
.csum_flags
& CSUM_IP
)
151 csum_flags
|= (CSUM_IP_CHECKED
| CSUM_IP_VALID
);
152 if (m
->m_pkthdr
.csum_flags
& CSUM_DELAY_DATA
)
153 csum_flags
|= (CSUM_DATA_VALID
| CSUM_PSEUDO_HDR
);
155 m
->m_pkthdr
.csum_flags
|= csum_flags
;
156 if (csum_flags
& CSUM_DATA_VALID
)
157 m
->m_pkthdr
.csum_data
= 0xffff;
159 if ((ifp
->if_capenable
& IFCAP_RSS
) == 0)
160 m
->m_flags
&= ~M_HASH
;
161 return (if_simloop(ifp
, m
, dst
->sa_family
, 0));
167 * This function is to support software emulation of hardware loopback,
168 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
169 * hear their own broadcasts, we create a copy of the packet that we
170 * would normally receive via a hardware loopback.
172 * This function expects the packet to include the media header of length hlen.
175 if_simloop(struct ifnet
*ifp
, struct mbuf
*m
, int af
, int hlen
)
179 KASSERT((m
->m_flags
& M_PKTHDR
) != 0, ("if_simloop: no HDR"));
180 m
->m_pkthdr
.rcvif
= ifp
;
182 /* BPF write needs to be handled specially */
183 if (af
== AF_UNSPEC
) {
184 KASSERT(m
->m_len
>= sizeof(int), ("if_simloop: m_len"));
185 af
= *(mtod(m
, int *));
186 m
->m_len
-= sizeof(int);
187 m
->m_pkthdr
.len
-= sizeof(int);
188 m
->m_data
+= sizeof(int);
195 if (ifp
->if_bpf
== NULL
)
198 if (ifp
->if_bpf
->bif_dlt
== DLT_NULL
) {
199 uint32_t bpf_af
= (uint32_t)af
;
200 bpf_ptap(ifp
->if_bpf
, m
, &bpf_af
, 4);
202 bpf_mtap(ifp
->if_bpf
, m
);
208 /* Strip away media header */
214 * altq for loop is just for debugging.
215 * only used when called for loop interface (not for
216 * a simplex interface).
218 if (ifq_is_enabled(&ifp
->if_snd
) && ifp
->if_start
== lo_altqstart
) {
219 struct altq_pktattr pktattr
;
223 * if the queueing discipline needs packet classification,
224 * do it before prepending link headers.
226 ifq_classify(&ifp
->if_snd
, m
, af
, &pktattr
);
228 M_PREPEND(m
, sizeof(int32_t), M_NOWAIT
);
231 afp
= mtod(m
, int32_t *);
234 return ifq_dispatch(ifp
, m
, &pktattr
);
238 /* Deliver to upper layer protocol */
247 m
->m_flags
|= M_LOOP
;
252 kprintf("if_simloop: can't handle af=%d\n", af
);
254 return (EAFNOSUPPORT
);
257 IFNET_STAT_INC(ifp
, ipackets
, 1);
258 IFNET_STAT_INC(ifp
, ibytes
, m
->m_pkthdr
.len
);
259 netisr_queue(isr
, m
);
265 lo_altqstart(struct ifnet
*ifp
, struct ifaltq_subque
*ifsq
)
273 m
= ifsq_dequeue(ifsq
);
278 afp
= mtod(m
, int32_t *);
280 m_adj(m
, sizeof(int32_t));
290 m
->m_flags
|= M_LOOP
;
295 kprintf("lo_altqstart: can't handle af%d\n", af
);
300 IFNET_STAT_INC(ifp
, ipackets
, 1);
301 IFNET_STAT_INC(ifp
, ibytes
, m
->m_pkthdr
.len
);
302 netisr_queue(isr
, m
);
309 lortrequest(int cmd
, struct rtentry
*rt
)
312 rt
->rt_rmx
.rmx_mtu
= rt
->rt_ifp
->if_mtu
; /* for ISO */
314 * For optimal performance, the send and receive buffers
315 * should be at least twice the MTU plus a little more for
318 rt
->rt_rmx
.rmx_recvpipe
= rt
->rt_rmx
.rmx_sendpipe
= 3 * LOMTU
;
323 * Process an ioctl request.
327 loioctl(struct ifnet
*ifp
, u_long cmd
, caddr_t data
, struct ucred
*cr
)
330 struct ifreq
*ifr
= (struct ifreq
*)data
;
335 ifp
->if_flags
|= IFF_UP
| IFF_RUNNING
;
336 ifa
= (struct ifaddr
*)data
;
337 ifa
->ifa_rtrequest
= lortrequest
;
339 * Everything else is done at a higher level.
346 error
= EAFNOSUPPORT
; /* XXX */
349 switch (ifr
->ifr_addr
.sa_family
) {
361 error
= EAFNOSUPPORT
;
367 ifp
->if_mtu
= ifr
->ifr_mtu
;
374 mask
= ifr
->ifr_reqcap
^ ifp
->if_capenable
;
375 if (mask
& IFCAP_HWCSUM
) {
376 ifp
->if_capenable
^= (mask
& IFCAP_HWCSUM
);
377 if (IFCAP_TXCSUM
& ifp
->if_capenable
)
378 ifp
->if_hwassist
= LO_CSUM_FEATURES
;
380 ifp
->if_hwassist
= 0;
382 if (mask
& IFCAP_RSS
)
383 ifp
->if_capenable
^= IFCAP_RSS
;