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33 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
38 * Loopback interface driver for protocol testing and timing.
41 #include "opt_atalk.h"
43 #include "opt_inet6.h"
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
51 #include <sys/malloc.h>
53 #include <sys/module.h>
54 #include <machine/bus.h>
56 #include <sys/socket.h>
57 #include <sys/sockio.h>
58 #include <sys/sysctl.h>
61 #include <net/if_types.h>
62 #include <net/netisr.h>
63 #include <net/route.h>
65 #include <net/bpfdesc.h>
68 #include <netinet/in.h>
69 #include <netinet/in_var.h>
73 #include <netipx/ipx.h>
74 #include <netipx/ipx_if.h>
79 #include <netinet/in.h>
81 #include <netinet6/in6_var.h>
82 #include <netinet/ip6.h>
86 #include <netatalk/at.h>
87 #include <netatalk/at_var.h>
91 #define LOMTU (1024+512)
92 #elif defined(LARGE_LOMTU)
101 struct ifnet sc_if; /* network-visible interface */
102 LIST_ENTRY(lo_softc) sc_next;
105 int loioctl(struct ifnet *, u_long, caddr_t);
106 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
107 int looutput(struct ifnet *ifp, struct mbuf *m,
108 struct sockaddr *dst, struct rtentry *rt);
109 int lo_clone_create(struct if_clone *, int);
110 void lo_clone_destroy(struct ifnet *);
112 struct ifnet *loif = NULL; /* Used externally */
114 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
116 static LIST_HEAD(lo_list, lo_softc) lo_list;
118 struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
119 lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
122 lo_clone_destroy(ifp)
129 /* XXX: destroying lo0 will lead to panics. */
130 KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
134 LIST_REMOVE(sc, sc_next);
139 lo_clone_create(ifc, unit)
140 struct if_clone *ifc;
145 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
147 sc->sc_if.if_name = LONAME;
148 sc->sc_if.if_unit = unit;
149 sc->sc_if.if_mtu = LOMTU;
150 sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
151 sc->sc_if.if_ioctl = loioctl;
152 sc->sc_if.if_output = looutput;
153 sc->sc_if.if_type = IFT_LOOP;
154 sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
155 sc->sc_if.if_softc = sc;
156 if_attach(&sc->sc_if);
157 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
158 LIST_INSERT_HEAD(&lo_list, sc, sc_next);
166 loop_modevent(module_t mod, int type, void *data)
171 if_clone_attach(&lo_cloner);
174 printf("loop module unload - not possible for this module type\n");
180 static moduledata_t loop_mod = {
186 DECLARE_MODULE(loop, loop_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
189 looutput(ifp, m, dst, rt)
191 register struct mbuf *m;
192 struct sockaddr *dst;
193 register struct rtentry *rt;
199 M_ASSERTPKTHDR(m); /* check if we have the packet header */
201 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
203 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
204 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
208 * KAME requires that the packet to be contiguous on the
209 * mbuf. We need to make that sure.
210 * this kind of code should be avoided.
212 * XXX: KAME may no longer need contiguous packets. Once
213 * that has been verified, the following code _should_ be
217 if (m && m->m_next != NULL) {
219 n = m_defrag(m, M_DONTWAIT);
231 ifp->if_obytes += m->m_pkthdr.len;
233 switch (dst->sa_family) {
240 printf("looutput: af=%d unexpected\n", dst->sa_family);
242 return (EAFNOSUPPORT);
245 return(if_simloop(ifp, m, dst->sa_family, 0));
251 * This function is to support software emulation of hardware loopback,
252 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
253 * hear their own broadcasts, we create a copy of the packet that we
254 * would normally receive via a hardware loopback.
256 * This function expects the packet to include the media header of length hlen.
260 if_simloop(ifp, m, af, hlen)
269 m->m_pkthdr.rcvif = ifp;
271 /* BPF write needs to be handled specially */
272 if (af == AF_UNSPEC) {
273 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
274 af = *(mtod(m, int *));
275 m->m_len -= sizeof(int);
276 m->m_pkthdr.len -= sizeof(int);
277 m->m_data += sizeof(int);
280 /* Let BPF see incoming packet */
282 struct mbuf m0, *n = m;
284 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
286 * We need to prepend the address family as
287 * a four byte field. Cons up a dummy header
288 * to pacify bpf. This is safe because bpf
289 * will only read from the mbuf (i.e., it won't
290 * try to free it or keep a pointer a to it).
294 m0.m_data = (char *)⁡
300 /* Strip away media header */
303 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
304 /* The alpha doesn't like unaligned data.
305 * We move data down in the first mbuf */
306 if (mtod(m, vm_offset_t) & 3) {
307 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
309 (char *)(mtod(m, vm_offset_t)
310 - (mtod(m, vm_offset_t) & 3)),
312 mtod(m,vm_offset_t) -= (mtod(m, vm_offset_t) & 3);
317 /* Deliver to upper layer protocol */
326 m->m_flags |= M_LOOP;
341 printf("if_simloop: can't handle af=%d\n", af);
343 return (EAFNOSUPPORT);
346 ifp->if_ibytes += m->m_pkthdr.len;
347 netisr_dispatch(isr, m);
353 lortrequest(cmd, rt, info)
356 struct rt_addrinfo *info;
361 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
363 * For optimal performance, the send and receive buffers
364 * should be at least twice the MTU plus a little more for
367 rt->rt_rmx.rmx_recvpipe =
368 rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
373 * Process an ioctl request.
377 loioctl(ifp, cmd, data)
378 register struct ifnet *ifp;
382 register struct ifaddr *ifa;
383 register struct ifreq *ifr = (struct ifreq *)data;
384 register int error = 0;
389 ifp->if_flags |= IFF_UP | IFF_RUNNING;
390 ifa = (struct ifaddr *)data;
391 ifa->ifa_rtrequest = lortrequest;
393 * Everything else is done at a higher level.
400 error = EAFNOSUPPORT; /* XXX */
403 switch (ifr->ifr_addr.sa_family) {
415 error = EAFNOSUPPORT;
421 ifp->if_mtu = ifr->ifr_mtu;