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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>
46 #include <sys/module.h>
47 #include <machine/bus.h>
49 #include <sys/socket.h>
50 #include <sys/sockio.h>
51 #include <sys/sysctl.h>
54 #include <net/if_clone.h>
55 #include <net/if_types.h>
56 #include <net/netisr.h>
57 #include <net/route.h>
62 #include <netinet/in.h>
63 #include <netinet/in_var.h>
67 #include <netipx/ipx.h>
68 #include <netipx/ipx_if.h>
73 #include <netinet/in.h>
75 #include <netinet6/in6_var.h>
76 #include <netinet/ip6.h>
80 #include <netatalk/at.h>
81 #include <netatalk/at_var.h>
84 #include <security/mac/mac_framework.h>
87 #define LOMTU (1024+512)
88 #elif defined(LARGE_LOMTU)
94 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
95 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_PSEUDO_HDR | \
96 CSUM_IP_CHECKED | CSUM_IP_VALID | \
99 int loioctl(struct ifnet *, u_long, caddr_t);
100 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
101 int looutput(struct ifnet *ifp, struct mbuf *m,
102 struct sockaddr *dst, struct route *ro);
103 static int lo_clone_create(struct if_clone *, int, caddr_t);
104 static void lo_clone_destroy(struct ifnet *);
106 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
109 static VNET_DEFINE(struct ifc_simple_data, lo_cloner_data);
110 static VNET_DEFINE(struct if_clone, lo_cloner);
111 #define V_lo_cloner_data VNET(lo_cloner_data)
112 #define V_lo_cloner VNET(lo_cloner)
115 IFC_SIMPLE_DECLARE(lo, 1);
118 lo_clone_destroy(struct ifnet *ifp)
122 /* XXX: destroying lo0 will lead to panics. */
123 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
132 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
136 ifp = if_alloc(IFT_LOOP);
140 if_initname(ifp, ifc->ifc_name, unit);
142 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
143 ifp->if_ioctl = loioctl;
144 ifp->if_output = looutput;
145 ifp->if_snd.ifq_maxlen = ifqmaxlen;
146 ifp->if_capabilities = ifp->if_capenable = IFCAP_HWCSUM;
147 ifp->if_hwassist = LO_CSUM_FEATURES;
149 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
157 vnet_loif_init(const void *unused __unused)
161 V_lo_cloner = lo_cloner;
162 V_lo_cloner_data = lo_cloner_data;
163 V_lo_cloner.ifc_data = &V_lo_cloner_data;
164 if_clone_attach(&V_lo_cloner);
166 if_clone_attach(&lo_cloner);
169 VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
170 vnet_loif_init, NULL);
174 vnet_loif_uninit(const void *unused __unused)
177 if_clone_detach(&V_lo_cloner);
180 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
181 vnet_loif_uninit, NULL);
185 loop_modevent(module_t mod, int type, void *data)
193 printf("loop module unload - not possible for this module type\n");
202 static moduledata_t loop_mod = {
208 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
211 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
215 struct rtentry *rt = NULL;
220 M_ASSERTPKTHDR(m); /* check if we have the packet header */
225 error = mac_ifnet_check_transmit(ifp, m);
232 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
234 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
235 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
239 ifp->if_obytes += m->m_pkthdr.len;
241 /* BPF writes need to be handled specially. */
242 if (dst->sa_family == AF_UNSPEC) {
243 bcopy(dst->sa_data, &af, sizeof(af));
248 switch (dst->sa_family) {
250 if (ifp->if_capenable & IFCAP_RXCSUM) {
251 m->m_pkthdr.csum_data = 0xffff;
252 m->m_pkthdr.csum_flags = LO_CSUM_SET;
254 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
260 printf("looutput: af=%d unexpected\n", dst->sa_family);
262 return (EAFNOSUPPORT);
265 return (if_simloop(ifp, m, dst->sa_family, 0));
271 * This function is to support software emulation of hardware loopback,
272 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
273 * hear their own broadcasts, we create a copy of the packet that we
274 * would normally receive via a hardware loopback.
276 * This function expects the packet to include the media header of length hlen.
279 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
284 m_tag_delete_nonpersistent(m);
285 m->m_pkthdr.rcvif = ifp;
288 mac_ifnet_create_mbuf(ifp, m);
292 * Let BPF see incoming packet in the following manner:
293 * - Emulated packet loopback for a simplex interface
294 * (net/if_ethersubr.c)
295 * -> passes it to ifp's BPF
296 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
297 * -> not passes it to any BPF
298 * - Normal packet loopback from myself to myself (net/if_loop.c)
299 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
302 if (bpf_peers_present(ifp->if_bpf)) {
303 bpf_mtap(ifp->if_bpf, m);
306 if (bpf_peers_present(V_loif->if_bpf)) {
307 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
308 /* XXX beware sizeof(af) != 4 */
312 * We need to prepend the address family.
314 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
319 /* Strip away media header */
322 #ifndef __NO_STRICT_ALIGNMENT
324 * Some archs do not like unaligned data, so
325 * we move data down in the first mbuf.
327 if (mtod(m, vm_offset_t) & 3) {
328 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
330 (char *)(mtod(m, vm_offset_t)
331 - (mtod(m, vm_offset_t) & 3)),
333 m->m_data -= (mtod(m,vm_offset_t) & 3);
338 /* Deliver to upper layer protocol */
347 m->m_flags |= M_LOOP;
362 printf("if_simloop: can't handle af=%d\n", af);
364 return (EAFNOSUPPORT);
367 ifp->if_ibytes += m->m_pkthdr.len;
368 netisr_queue(isr, m); /* mbuf is free'd on failure. */
374 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
378 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
382 * Process an ioctl request.
386 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
389 struct ifreq *ifr = (struct ifreq *)data;
394 ifp->if_flags |= IFF_UP;
395 ifp->if_drv_flags |= IFF_DRV_RUNNING;
396 ifa = (struct ifaddr *)data;
397 ifa->ifa_rtrequest = lortrequest;
399 * Everything else is done at a higher level.
406 error = EAFNOSUPPORT; /* XXX */
409 switch (ifr->ifr_addr.sa_family) {
421 error = EAFNOSUPPORT;
427 ifp->if_mtu = ifr->ifr_mtu;
434 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
435 if ((mask & IFCAP_RXCSUM) != 0)
436 ifp->if_capenable ^= IFCAP_RXCSUM;
437 if ((mask & IFCAP_TXCSUM) != 0)
438 ifp->if_capenable ^= IFCAP_TXCSUM;
439 if (ifp->if_capenable & IFCAP_TXCSUM)
440 ifp->if_hwassist = LO_CSUM_FEATURES;
442 ifp->if_hwassist = 0;