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31 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
36 * Discard interface driver for protocol testing and timing.
37 * (Based on the loopback.)
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
46 #include <sys/socket.h>
47 #include <sys/sockio.h>
50 #include <net/if_var.h>
51 #include <net/if_private.h>
52 #include <net/if_clone.h>
53 #include <net/if_types.h>
54 #include <net/route.h>
59 #include "opt_inet6.h"
62 #define DSMTU (1024+512)
71 static int discoutput(struct ifnet *, struct mbuf *,
72 const struct sockaddr *, struct route *);
73 static int discioctl(struct ifnet *, u_long, caddr_t);
74 static int disc_clone_create(struct if_clone *, int, caddr_t);
75 static void disc_clone_destroy(struct ifnet *);
77 static const char discname[] = "disc";
78 static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
80 VNET_DEFINE_STATIC(struct if_clone *, disc_cloner);
81 #define V_disc_cloner VNET(disc_cloner)
84 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
87 struct disc_softc *sc;
89 sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
90 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
97 if_initname(ifp, discname, unit);
100 * IFF_LOOPBACK should not be removed from disc's flags because
101 * it controls what PF-specific routes are magically added when
102 * a network address is assigned to the interface. Things just
103 * won't work as intended w/o such routes because the output
104 * interface selection for a packet is totally route-driven.
105 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
106 * IFF_POINTOPOINT, but it would result in different properties
109 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
110 ifp->if_drv_flags = IFF_DRV_RUNNING;
111 ifp->if_ioctl = discioctl;
112 ifp->if_output = discoutput;
115 ifp->if_snd.ifq_maxlen = 20;
117 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
123 disc_clone_destroy(struct ifnet *ifp)
125 struct disc_softc *sc;
137 vnet_disc_init(const void *unused __unused)
140 V_disc_cloner = if_clone_simple(discname, disc_clone_create,
141 disc_clone_destroy, 0);
143 VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
144 vnet_disc_init, NULL);
147 vnet_disc_uninit(const void *unused __unused)
150 if_clone_detach(V_disc_cloner);
152 VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
153 vnet_disc_uninit, NULL);
156 disc_modevent(module_t mod, int type, void *data)
169 static moduledata_t disc_mod = {
175 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
178 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
185 /* BPF writes need to be handled specially. */
186 if (dst->sa_family == AF_UNSPEC)
187 bcopy(dst->sa_data, &af, sizeof(af));
189 af = RO_GET_FAMILY(ro, dst);
191 if (bpf_peers_present(ifp->if_bpf))
192 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
194 m->m_pkthdr.rcvif = ifp;
196 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
197 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
204 * Process an ioctl request.
207 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
209 struct ifreq *ifr = (struct ifreq *)data;
214 ifp->if_flags |= IFF_UP;
217 * Everything else is done at a higher level.
223 error = EAFNOSUPPORT; /* XXX */
226 switch (ifr->ifr_addr.sa_family) {
236 error = EAFNOSUPPORT;
241 ifp->if_mtu = ifr->ifr_mtu;