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33 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/net/if_disc.c,v 1.26.2.2 2001/12/20 10:30:16 ru Exp $
38 * Discard interface driver for protocol testing and timing.
39 * (Based on the loopback.)
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/module.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
51 #include <net/if_types.h>
52 #include <net/route.h>
56 #include "opt_inet6.h"
59 #define DSMTU (1024+512)
64 static void discattach __P((void));
66 static struct ifnet discif;
67 static int discoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
69 static void discrtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info);
70 static int discioctl(struct ifnet *, u_long, caddr_t);
76 register struct ifnet *ifp = &discif;
80 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
81 ifp->if_ioctl = discioctl;
82 ifp->if_output = discoutput;
83 ifp->if_type = IFT_LOOP;
86 ifp->if_snd.ifq_maxlen = 20;
88 bpfattach(ifp, DLT_NULL, sizeof(u_int));
92 disc_modevent(module_t mod, int type, void *data)
99 printf("if_disc module unload - not possible for this module type\n");
105 static moduledata_t disc_mod = {
111 DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
114 discoutput(ifp, m, dst, rt)
116 register struct mbuf *m;
117 struct sockaddr *dst;
118 register struct rtentry *rt;
120 if ((m->m_flags & M_PKTHDR) == 0)
121 panic("discoutput no HDR");
122 /* BPF write needs to be handled specially */
123 if (dst->sa_family == AF_UNSPEC) {
124 dst->sa_family = *(mtod(m, int *));
125 m->m_len -= sizeof(int);
126 m->m_pkthdr.len -= sizeof(int);
127 m->m_data += sizeof(int);
132 * We need to prepend the address family as
133 * a four byte field. Cons up a dummy header
134 * to pacify bpf. This is safe because bpf
135 * will only read from the mbuf (i.e., it won't
136 * try to free it or keep a pointer a to it).
139 u_int af = dst->sa_family;
143 m0.m_data = (char *)⁡
145 bpf_mtap(&discif, &m0);
147 m->m_pkthdr.rcvif = ifp;
150 ifp->if_obytes += m->m_pkthdr.len;
158 discrtrequest(cmd, rt, info)
161 struct rt_addrinfo *info;
164 rt->rt_rmx.rmx_mtu = DSMTU;
168 * Process an ioctl request.
172 discioctl(ifp, cmd, data)
173 register struct ifnet *ifp;
177 register struct ifaddr *ifa;
178 register struct ifreq *ifr = (struct ifreq *)data;
179 register int error = 0;
184 ifp->if_flags |= IFF_UP;
185 ifa = (struct ifaddr *)data;
187 ifa->ifa_rtrequest = discrtrequest;
189 * Everything else is done at a higher level.
196 error = EAFNOSUPPORT; /* XXX */
199 switch (ifr->ifr_addr.sa_family) {
211 error = EAFNOSUPPORT;
217 ifp->if_mtu = ifr->ifr_mtu;