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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)
97 LIST_ENTRY(lo_softc) sc_next;
100 int loioctl(struct ifnet *, u_long, caddr_t);
101 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
102 int looutput(struct ifnet *ifp, struct mbuf *m,
103 struct sockaddr *dst, struct rtentry *rt);
104 static int lo_clone_create(struct if_clone *, int, caddr_t);
105 static void lo_clone_destroy(struct ifnet *);
107 struct ifnet *loif = NULL; /* Used externally */
109 static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
111 static struct mtx lo_mtx;
112 static LIST_HEAD(lo_list, lo_softc) lo_list;
114 IFC_SIMPLE_DECLARE(lo, 1);
117 lo_clone_destroy(struct ifnet *ifp)
123 /* XXX: destroying lo0 will lead to panics. */
124 KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
127 LIST_REMOVE(sc, sc_next);
136 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
141 MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
142 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
148 if_initname(ifp, ifc->ifc_name, unit);
150 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
151 ifp->if_ioctl = loioctl;
152 ifp->if_output = looutput;
153 ifp->if_snd.ifq_maxlen = ifqmaxlen;
156 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
158 LIST_INSERT_HEAD(&lo_list, sc, sc_next);
167 loop_modevent(module_t mod, int type, void *data)
171 mtx_init(&lo_mtx, "lo_mtx", NULL, MTX_DEF);
173 if_clone_attach(&lo_cloner);
177 printf("loop module unload - not possible for this module type\n");
186 static moduledata_t loop_mod = {
192 DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
195 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
200 M_ASSERTPKTHDR(m); /* check if we have the packet header */
202 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
204 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
205 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
209 ifp->if_obytes += m->m_pkthdr.len;
211 /* BPF writes need to be handled specially. */
212 if (dst->sa_family == AF_UNSPEC) {
213 bcopy(dst->sa_data, &af, sizeof(af));
218 switch (dst->sa_family) {
225 printf("looutput: af=%d unexpected\n", dst->sa_family);
227 return (EAFNOSUPPORT);
230 return (if_simloop(ifp, m, dst->sa_family, 0));
236 * This function is to support software emulation of hardware loopback,
237 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
238 * hear their own broadcasts, we create a copy of the packet that we
239 * would normally receive via a hardware loopback.
241 * This function expects the packet to include the media header of length hlen.
244 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
249 m_tag_delete_nonpersistent(m);
250 m->m_pkthdr.rcvif = ifp;
253 * Let BPF see incoming packet in the following manner:
254 * - Emulated packet loopback for a simplex interface
255 * (net/if_ethersubr.c)
256 * -> passes it to ifp's BPF
257 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
258 * -> not passes it to any BPF
259 * - Normal packet loopback from myself to myself (net/if_loop.c)
260 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
263 if (bpf_peers_present(ifp->if_bpf)) {
264 bpf_mtap(ifp->if_bpf, m);
267 if (bpf_peers_present(loif->if_bpf)) {
268 if ((m->m_flags & M_MCAST) == 0 || loif == ifp) {
269 /* XXX beware sizeof(af) != 4 */
273 * We need to prepend the address family.
275 bpf_mtap2(loif->if_bpf, &af1, sizeof(af1), m);
280 /* Strip away media header */
283 #ifndef __NO_STRICT_ALIGNMENT
285 * Some archs do not like unaligned data, so
286 * we move data down in the first mbuf.
288 if (mtod(m, vm_offset_t) & 3) {
289 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
291 (char *)(mtod(m, vm_offset_t)
292 - (mtod(m, vm_offset_t) & 3)),
294 m->m_data -= (mtod(m,vm_offset_t) & 3);
299 /* Deliver to upper layer protocol */
308 m->m_flags |= M_LOOP;
323 printf("if_simloop: can't handle af=%d\n", af);
325 return (EAFNOSUPPORT);
328 ifp->if_ibytes += m->m_pkthdr.len;
329 netisr_queue(isr, m); /* mbuf is free'd on failure. */
335 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
339 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
343 * Process an ioctl request.
347 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
350 struct ifreq *ifr = (struct ifreq *)data;
355 ifp->if_flags |= IFF_UP;
356 ifp->if_drv_flags |= IFF_DRV_RUNNING;
357 ifa = (struct ifaddr *)data;
358 ifa->ifa_rtrequest = lortrequest;
360 * Everything else is done at a higher level.
367 error = EAFNOSUPPORT; /* XXX */
370 switch (ifr->ifr_addr.sa_family) {
382 error = EAFNOSUPPORT;
388 ifp->if_mtu = ifr->ifr_mtu;