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29 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
34 * Discard interface driver for protocol testing and timing.
35 * (Based on the loopback.)
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
48 #include <net/if_var.h>
49 #include <net/if_clone.h>
50 #include <net/if_types.h>
51 #include <net/route.h>
56 #include "opt_inet6.h"
59 #define DSMTU (1024+512)
68 static int discoutput(struct ifnet *, struct mbuf *,
69 const struct sockaddr *, struct route *);
70 static void discrtrequest(int, struct rtentry *, struct rt_addrinfo *);
71 static int discioctl(struct ifnet *, u_long, caddr_t);
72 static int disc_clone_create(struct if_clone *, int, caddr_t);
73 static void disc_clone_destroy(struct ifnet *);
75 static const char discname[] = "disc";
76 static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
78 static VNET_DEFINE(struct if_clone *, disc_cloner);
79 #define V_disc_cloner VNET(disc_cloner)
82 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
85 struct disc_softc *sc;
87 sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
88 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
95 if_initname(ifp, discname, unit);
98 * IFF_LOOPBACK should not be removed from disc's flags because
99 * it controls what PF-specific routes are magically added when
100 * a network address is assigned to the interface. Things just
101 * won't work as intended w/o such routes because the output
102 * interface selection for a packet is totally route-driven.
103 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
104 * IFF_POINTOPOINT, but it would result in different properties
107 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
108 ifp->if_drv_flags = IFF_DRV_RUNNING;
109 ifp->if_ioctl = discioctl;
110 ifp->if_output = discoutput;
113 ifp->if_snd.ifq_maxlen = 20;
115 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
121 disc_clone_destroy(struct ifnet *ifp)
123 struct disc_softc *sc;
135 vnet_disc_init(const void *unused __unused)
138 V_disc_cloner = if_clone_simple(discname, disc_clone_create,
139 disc_clone_destroy, 0);
141 VNET_SYSINIT(vnet_disc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
142 vnet_disc_init, NULL);
145 vnet_disc_uninit(const void *unused __unused)
148 if_clone_detach(V_disc_cloner);
150 VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
151 vnet_disc_uninit, NULL);
154 disc_modevent(module_t mod, int type, void *data)
167 static moduledata_t disc_mod = {
173 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
176 discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
183 /* BPF writes need to be handled specially. */
184 if (dst->sa_family == AF_UNSPEC)
185 bcopy(dst->sa_data, &af, sizeof(af));
189 if (bpf_peers_present(ifp->if_bpf))
190 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
192 m->m_pkthdr.rcvif = ifp;
194 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
195 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
203 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
211 * Process an ioctl request.
214 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
217 struct ifreq *ifr = (struct ifreq *)data;
222 ifp->if_flags |= IFF_UP;
223 ifa = (struct ifaddr *)data;
225 ifa->ifa_rtrequest = discrtrequest;
227 * Everything else is done at a higher level.
233 error = EAFNOSUPPORT; /* XXX */
236 switch (ifr->ifr_addr.sa_family) {
246 error = EAFNOSUPPORT;
251 ifp->if_mtu = ifr->ifr_mtu;