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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_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
96 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
98 CSUM_IP_CHECKED | CSUM_IP_VALID | \
101 int loioctl(struct ifnet *, u_long, caddr_t);
102 static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
103 int looutput(struct ifnet *ifp, struct mbuf *m,
104 struct sockaddr *dst, struct route *ro);
105 static int lo_clone_create(struct if_clone *, int, caddr_t);
106 static void lo_clone_destroy(struct ifnet *);
108 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
111 static VNET_DEFINE(struct ifc_simple_data, lo_cloner_data);
112 static VNET_DEFINE(struct if_clone, lo_cloner);
113 #define V_lo_cloner_data VNET(lo_cloner_data)
114 #define V_lo_cloner VNET(lo_cloner)
117 IFC_SIMPLE_DECLARE(lo, 1);
120 lo_clone_destroy(struct ifnet *ifp)
124 /* XXX: destroying lo0 will lead to panics. */
125 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
134 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
138 ifp = if_alloc(IFT_LOOP);
142 if_initname(ifp, ifc->ifc_name, unit);
144 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
145 ifp->if_ioctl = loioctl;
146 ifp->if_output = looutput;
147 ifp->if_snd.ifq_maxlen = ifqmaxlen;
148 ifp->if_capabilities = ifp->if_capenable =
149 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
150 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
152 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
160 vnet_loif_init(const void *unused __unused)
164 V_lo_cloner = lo_cloner;
165 V_lo_cloner_data = lo_cloner_data;
166 V_lo_cloner.ifc_data = &V_lo_cloner_data;
167 if_clone_attach(&V_lo_cloner);
169 if_clone_attach(&lo_cloner);
172 VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
173 vnet_loif_init, NULL);
177 vnet_loif_uninit(const void *unused __unused)
180 if_clone_detach(&V_lo_cloner);
183 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
184 vnet_loif_uninit, NULL);
188 loop_modevent(module_t mod, int type, void *data)
196 printf("loop module unload - not possible for this module type\n");
205 static moduledata_t loop_mod = {
211 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
214 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
218 struct rtentry *rt = NULL;
223 M_ASSERTPKTHDR(m); /* check if we have the packet header */
228 error = mac_ifnet_check_transmit(ifp, m);
235 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
237 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
238 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
242 ifp->if_obytes += m->m_pkthdr.len;
244 /* BPF writes need to be handled specially. */
245 if (dst->sa_family == AF_UNSPEC) {
246 bcopy(dst->sa_data, &af, sizeof(af));
251 switch (dst->sa_family) {
253 if (ifp->if_capenable & IFCAP_RXCSUM) {
254 m->m_pkthdr.csum_data = 0xffff;
255 m->m_pkthdr.csum_flags = LO_CSUM_SET;
257 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
262 * XXX-BZ for now always claim the checksum is good despite
263 * any interface flags. This is a workaround for 9.1-R and
264 * a proper solution ought to be sought later.
266 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
267 m->m_pkthdr.csum_data = 0xffff;
268 m->m_pkthdr.csum_flags = LO_CSUM_SET;
271 m->m_pkthdr.csum_data = 0xffff;
272 m->m_pkthdr.csum_flags = LO_CSUM_SET;
274 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
280 printf("looutput: af=%d unexpected\n", dst->sa_family);
282 return (EAFNOSUPPORT);
285 return (if_simloop(ifp, m, dst->sa_family, 0));
291 * This function is to support software emulation of hardware loopback,
292 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
293 * hear their own broadcasts, we create a copy of the packet that we
294 * would normally receive via a hardware loopback.
296 * This function expects the packet to include the media header of length hlen.
299 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
304 m_tag_delete_nonpersistent(m);
305 m->m_pkthdr.rcvif = ifp;
308 mac_ifnet_create_mbuf(ifp, m);
312 * Let BPF see incoming packet in the following manner:
313 * - Emulated packet loopback for a simplex interface
314 * (net/if_ethersubr.c)
315 * -> passes it to ifp's BPF
316 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
317 * -> not passes it to any BPF
318 * - Normal packet loopback from myself to myself (net/if_loop.c)
319 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
322 if (bpf_peers_present(ifp->if_bpf)) {
323 bpf_mtap(ifp->if_bpf, m);
326 if (bpf_peers_present(V_loif->if_bpf)) {
327 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
328 /* XXX beware sizeof(af) != 4 */
332 * We need to prepend the address family.
334 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
339 /* Strip away media header */
342 #ifndef __NO_STRICT_ALIGNMENT
344 * Some archs do not like unaligned data, so
345 * we move data down in the first mbuf.
347 if (mtod(m, vm_offset_t) & 3) {
348 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
350 (char *)(mtod(m, vm_offset_t)
351 - (mtod(m, vm_offset_t) & 3)),
353 m->m_data -= (mtod(m,vm_offset_t) & 3);
358 /* Deliver to upper layer protocol */
367 m->m_flags |= M_LOOP;
382 printf("if_simloop: can't handle af=%d\n", af);
384 return (EAFNOSUPPORT);
387 ifp->if_ibytes += m->m_pkthdr.len;
388 netisr_queue(isr, m); /* mbuf is free'd on failure. */
394 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
398 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
402 * Process an ioctl request.
406 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
409 struct ifreq *ifr = (struct ifreq *)data;
414 ifp->if_flags |= IFF_UP;
415 ifp->if_drv_flags |= IFF_DRV_RUNNING;
416 ifa = (struct ifaddr *)data;
417 ifa->ifa_rtrequest = lortrequest;
419 * Everything else is done at a higher level.
426 error = EAFNOSUPPORT; /* XXX */
429 switch (ifr->ifr_addr.sa_family) {
441 error = EAFNOSUPPORT;
447 ifp->if_mtu = ifr->ifr_mtu;
454 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
455 if ((mask & IFCAP_RXCSUM) != 0)
456 ifp->if_capenable ^= IFCAP_RXCSUM;
457 if ((mask & IFCAP_TXCSUM) != 0)
458 ifp->if_capenable ^= IFCAP_TXCSUM;
459 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
461 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
467 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
469 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
475 ifp->if_hwassist = 0;
476 if (ifp->if_capenable & IFCAP_TXCSUM)
477 ifp->if_hwassist = LO_CSUM_FEATURES;
479 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
480 ifp->if_hwassist |= LO_CSUM_FEATURES6;