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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_clone.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
54 #include "opt_inet6.h"
57 #define DSMTU (1024+512)
62 #define DISCNAME "disc"
68 static int discoutput(struct ifnet *, struct mbuf *,
69 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 MALLOC_DEFINE(M_DISC, DISCNAME, "Discard interface");
77 IFC_SIMPLE_DECLARE(disc, 0);
80 disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
83 struct disc_softc *sc;
85 sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
86 ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
93 if_initname(ifp, ifc->ifc_name, unit);
96 * IFF_LOOPBACK should not be removed from disc's flags because
97 * it controls what PF-specific routes are magically added when
98 * a network address is assigned to the interface. Things just
99 * won't work as intended w/o such routes because the output
100 * interface selection for a packet is totally route-driven.
101 * A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
102 * IFF_POINTOPOINT, but it would result in different properties
105 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
106 ifp->if_drv_flags = IFF_DRV_RUNNING;
107 ifp->if_ioctl = discioctl;
108 ifp->if_output = discoutput;
111 ifp->if_snd.ifq_maxlen = 20;
113 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
119 disc_clone_destroy(struct ifnet *ifp)
121 struct disc_softc *sc;
133 disc_modevent(module_t mod, int type, void *data)
138 if_clone_attach(&disc_cloner);
141 if_clone_detach(&disc_cloner);
149 static moduledata_t disc_mod = {
155 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
158 discoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
165 /* BPF writes need to be handled specially. */
166 if (dst->sa_family == AF_UNSPEC) {
167 bcopy(dst->sa_data, &af, sizeof(af));
171 if (bpf_peers_present(ifp->if_bpf)) {
172 u_int af = dst->sa_family;
173 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
175 m->m_pkthdr.rcvif = ifp;
178 ifp->if_obytes += m->m_pkthdr.len;
186 discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
189 rt->rt_rmx.rmx_mtu = DSMTU;
193 * Process an ioctl request.
196 discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
199 struct ifreq *ifr = (struct ifreq *)data;
205 ifp->if_flags |= IFF_UP;
206 ifa = (struct ifaddr *)data;
208 ifa->ifa_rtrequest = discrtrequest;
210 * Everything else is done at a higher level.
217 error = EAFNOSUPPORT; /* XXX */
220 switch (ifr->ifr_addr.sa_family) {
232 error = EAFNOSUPPORT;
238 ifp->if_mtu = ifr->ifr_mtu;