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31 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
36 * Loopback interface driver for protocol testing and timing.
40 #include "opt_inet6.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
47 #include <sys/module.h>
48 #include <machine/bus.h>
50 #include <sys/socket.h>
51 #include <sys/sockio.h>
52 #include <sys/sysctl.h>
55 #include <net/if_var.h>
56 #include <net/if_private.h>
57 #include <net/if_clone.h>
58 #include <net/if_types.h>
59 #include <net/netisr.h>
60 #include <net/route.h>
65 #include <netinet/in.h>
66 #include <netinet/in_var.h>
71 #include <netinet/in.h>
73 #include <netinet6/in6_var.h>
74 #include <netinet/ip6.h>
77 #include <security/mac/mac_framework.h>
80 #define LOMTU (1024+512)
81 #elif defined(LARGE_LOMTU)
87 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
88 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
89 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
91 CSUM_IP_CHECKED | CSUM_IP_VALID | \
94 static int loioctl(struct ifnet *, u_long, caddr_t);
95 static int looutput(struct ifnet *ifp, struct mbuf *m,
96 const struct sockaddr *dst, struct route *ro);
98 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
101 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
102 #define V_lo_cloner VNET(lo_cloner)
105 static struct if_clone *lo_cloner;
106 static const char loname[] = "lo";
109 lo_clone_destroy(struct if_clone *ifc, struct ifnet *ifp, uint32_t flags)
111 if (ifp->if_dunit == 0 && (flags & IFC_F_FORCE) == 0)
115 /* XXX: destroying lo0 will lead to panics. */
116 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
127 lo_clone_create(struct if_clone *ifc, char *name, size_t len,
128 struct ifc_data *ifd, struct ifnet **ifpp)
132 ifp = if_alloc(IFT_LOOP);
136 if_initname(ifp, loname, ifd->unit);
138 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
139 ifp->if_ioctl = loioctl;
140 ifp->if_output = looutput;
141 ifp->if_snd.ifq_maxlen = ifqmaxlen;
142 ifp->if_capabilities = ifp->if_capenable =
143 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
144 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
146 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
155 vnet_loif_init(const void *unused __unused)
157 struct if_clone_addreq req = {
158 .create_f = lo_clone_create,
159 .destroy_f = lo_clone_destroy,
160 .flags = IFC_F_AUTOUNIT,
162 lo_cloner = ifc_attach_cloner(loname, &req);
164 V_lo_cloner = lo_cloner;
166 struct ifc_data ifd = { .unit = 0 };
167 ifc_create_ifp(loname, &ifd, NULL);
169 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
170 vnet_loif_init, NULL);
174 vnet_loif_uninit(const void *unused __unused)
177 ifc_detach_cloner(V_lo_cloner);
180 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
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, const struct sockaddr *dst,
219 M_ASSERTPKTHDR(m); /* check if we have the packet header */
222 error = mac_ifnet_check_transmit(ifp, m);
229 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
231 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
234 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
235 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
241 /* BPF writes need to be handled specially. */
242 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
243 bcopy(dst->sa_data, &af, sizeof(af));
245 af = RO_GET_FAMILY(ro, dst);
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;
259 * XXX-BZ for now always claim the checksum is good despite
260 * any interface flags. This is a workaround for 9.1-R and
261 * a proper solution ought to be sought later.
263 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
264 m->m_pkthdr.csum_data = 0xffff;
265 m->m_pkthdr.csum_flags = LO_CSUM_SET;
268 m->m_pkthdr.csum_data = 0xffff;
269 m->m_pkthdr.csum_flags = LO_CSUM_SET;
271 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
274 printf("looutput: af=%d unexpected\n", af);
276 return (EAFNOSUPPORT);
279 return (if_simloop(ifp, m, af, 0));
285 * This function is to support software emulation of hardware loopback,
286 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
287 * hear their own broadcasts, we create a copy of the packet that we
288 * would normally receive via a hardware loopback.
290 * This function expects the packet to include the media header of length hlen.
293 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
298 m_tag_delete_nonpersistent(m);
299 m->m_pkthdr.rcvif = ifp;
302 mac_ifnet_create_mbuf(ifp, m);
306 * Let BPF see incoming packet in the following manner:
307 * - Emulated packet loopback for a simplex interface
308 * (net/if_ethersubr.c)
309 * -> passes it to ifp's BPF
310 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
311 * -> not passes it to any BPF
312 * - Normal packet loopback from myself to myself (net/if_loop.c)
313 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
316 if (bpf_peers_present(ifp->if_bpf)) {
317 bpf_mtap(ifp->if_bpf, m);
320 if (bpf_peers_present(V_loif->if_bpf)) {
321 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
322 /* XXX beware sizeof(af) != 4 */
326 * We need to prepend the address family.
328 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
333 /* Strip away media header */
336 #ifndef __NO_STRICT_ALIGNMENT
338 * Some archs do not like unaligned data, so
339 * we move data down in the first mbuf.
341 if (mtod(m, vm_offset_t) & 3) {
342 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
344 (char *)(mtod(m, vm_offset_t)
345 - (mtod(m, vm_offset_t) & 3)),
347 m->m_data -= (mtod(m,vm_offset_t) & 3);
352 /* Deliver to upper layer protocol */
361 m->m_flags |= M_LOOP;
366 printf("if_simloop: can't handle af=%d\n", af);
368 return (EAFNOSUPPORT);
370 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
371 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
372 netisr_queue(isr, m); /* mbuf is free'd on failure. */
377 * Process an ioctl request.
380 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
382 struct ifreq *ifr = (struct ifreq *)data;
387 ifp->if_flags |= IFF_UP;
388 ifp->if_drv_flags |= IFF_DRV_RUNNING;
389 if_link_state_change(ifp, LINK_STATE_UP);
391 * Everything else is done at a higher level.
398 error = EAFNOSUPPORT; /* XXX */
401 switch (ifr->ifr_addr.sa_family) {
412 error = EAFNOSUPPORT;
418 ifp->if_mtu = ifr->ifr_mtu;
422 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
423 LINK_STATE_UP: LINK_STATE_DOWN);
427 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
428 if ((mask & IFCAP_RXCSUM) != 0)
429 ifp->if_capenable ^= IFCAP_RXCSUM;
430 if ((mask & IFCAP_TXCSUM) != 0)
431 ifp->if_capenable ^= IFCAP_TXCSUM;
432 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
434 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
440 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
442 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
448 ifp->if_hwassist = 0;
449 if (ifp->if_capenable & IFCAP_TXCSUM)
450 ifp->if_hwassist = LO_CSUM_FEATURES;
452 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
453 ifp->if_hwassist |= LO_CSUM_FEATURES6;