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29 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
34 * Loopback interface driver for protocol testing and timing.
37 #include "opt_atalk.h"
39 #include "opt_inet6.h"
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
47 #include <sys/module.h>
48 #include <machine/bus.h>
50 #include <sys/socket.h>
51 #include <sys/sockio.h>
52 #include <sys/sysctl.h>
55 #include <net/if_clone.h>
56 #include <net/if_types.h>
57 #include <net/netisr.h>
58 #include <net/route.h>
60 #include <net/bpfdesc.h>
63 #include <netinet/in.h>
64 #include <netinet/in_var.h>
68 #include <netipx/ipx.h>
69 #include <netipx/ipx_if.h>
74 #include <netinet/in.h>
76 #include <netinet6/in6_var.h>
77 #include <netinet/ip6.h>
81 #include <netatalk/at.h>
82 #include <netatalk/at_var.h>
86 #define LOMTU (1024+512)
87 #elif defined(LARGE_LOMTU)
99 int loioctl(struct ifnet *, u_long, caddr_t);
100 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
101 int looutput(struct ifnet *ifp, struct mbuf *m,
102 struct sockaddr *dst, struct rtentry *rt);
103 static int lo_clone_create(struct if_clone *, int, caddr_t);
104 static void lo_clone_destroy(struct ifnet *);
106 struct ifnet *loif = NULL; /* Used externally */
108 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
110 IFC_SIMPLE_DECLARE(lo, 1);
113 lo_clone_destroy(ifp)
120 /* XXX: destroying lo0 will lead to panics. */
121 KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
130 lo_clone_create(ifc, unit, params)
131 struct if_clone *ifc;
138 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
139 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
145 if_initname(ifp, ifc->ifc_name, unit);
147 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
148 ifp->if_ioctl = loioctl;
149 ifp->if_output = looutput;
150 ifp->if_snd.ifq_maxlen = ifqmaxlen;
153 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
161 loop_modevent(module_t mod, int type, void *data)
165 if_clone_attach(&lo_cloner);
168 printf("loop module unload - not possible for this module type\n");
176 static moduledata_t loop_mod = {
182 DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
185 looutput(ifp, m, dst, rt)
187 register struct mbuf *m;
188 struct sockaddr *dst;
189 register struct rtentry *rt;
193 M_ASSERTPKTHDR(m); /* check if we have the packet header */
195 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
197 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
198 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
202 ifp->if_obytes += m->m_pkthdr.len;
204 /* BPF writes need to be handled specially. */
205 if (dst->sa_family == AF_UNSPEC) {
206 bcopy(dst->sa_data, &af, sizeof(af));
211 switch (dst->sa_family) {
218 printf("looutput: af=%d unexpected\n", dst->sa_family);
220 return (EAFNOSUPPORT);
223 return(if_simloop(ifp, m, dst->sa_family, 0));
229 * This function is to support software emulation of hardware loopback,
230 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
231 * hear their own broadcasts, we create a copy of the packet that we
232 * would normally receive via a hardware loopback.
234 * This function expects the packet to include the media header of length hlen.
238 if_simloop(ifp, m, af, hlen)
247 m_tag_delete_nonpersistent(m);
248 m->m_pkthdr.rcvif = ifp;
251 * Let BPF see incoming packet in the following manner:
252 * - Emulated packet loopback for a simplex interface
253 * (net/if_ethersubr.c)
254 * -> passes it to ifp's BPF
255 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
256 * -> not passes it to any BPF
257 * - Normal packet loopback from myself to myself (net/if_loop.c)
258 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
261 if (bpf_peers_present(ifp->if_bpf)) {
262 bpf_mtap(ifp->if_bpf, m);
265 if (bpf_peers_present(loif->if_bpf)) {
266 if ((m->m_flags & M_MCAST) == 0 || loif == ifp) {
267 /* XXX beware sizeof(af) != 4 */
271 * We need to prepend the address family.
273 bpf_mtap2(loif->if_bpf, &af1, sizeof(af1), m);
278 /* Strip away media header */
281 #ifndef __NO_STRICT_ALIGNMENT
283 * Some archs do not like unaligned data, so
284 * we move data down in the first mbuf.
286 if (mtod(m, vm_offset_t) & 3) {
287 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
289 (char *)(mtod(m, vm_offset_t)
290 - (mtod(m, vm_offset_t) & 3)),
292 m->m_data -= (mtod(m,vm_offset_t) & 3);
297 /* Deliver to upper layer protocol */
306 m->m_flags |= M_LOOP;
321 printf("if_simloop: can't handle af=%d\n", af);
323 return (EAFNOSUPPORT);
326 ifp->if_ibytes += m->m_pkthdr.len;
327 netisr_queue(isr, m); /* mbuf is free'd on failure. */
333 lortrequest(cmd, rt, info)
336 struct rt_addrinfo *info;
339 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
343 * Process an ioctl request.
347 loioctl(ifp, cmd, data)
348 register struct ifnet *ifp;
352 register struct ifaddr *ifa;
353 register struct ifreq *ifr = (struct ifreq *)data;
354 register int error = 0;
359 ifp->if_flags |= IFF_UP;
360 ifp->if_drv_flags |= IFF_DRV_RUNNING;
361 ifa = (struct ifaddr *)data;
362 ifa->ifa_rtrequest = lortrequest;
364 * Everything else is done at a higher level.
371 error = EAFNOSUPPORT; /* XXX */
374 switch (ifr->ifr_addr.sa_family) {
386 error = EAFNOSUPPORT;
392 ifp->if_mtu = ifr->ifr_mtu;