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31 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
35 * Loopback interface driver for protocol testing and timing.
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_var.h>
55 #include <net/if_clone.h>
56 #include <net/if_types.h>
57 #include <net/netisr.h>
58 #include <net/route.h>
63 #include <netinet/in.h>
64 #include <netinet/in_var.h>
69 #include <netinet/in.h>
71 #include <netinet6/in6_var.h>
72 #include <netinet/ip6.h>
75 #include <security/mac/mac_framework.h>
78 #define LOMTU (1024+512)
79 #elif defined(LARGE_LOMTU)
85 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
86 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
87 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
89 CSUM_IP_CHECKED | CSUM_IP_VALID | \
92 int loioctl(struct ifnet *, u_long, caddr_t);
93 int looutput(struct ifnet *ifp, struct mbuf *m,
94 const struct sockaddr *dst, struct route *ro);
95 static int lo_clone_create(struct if_clone *, int, caddr_t);
96 static void lo_clone_destroy(struct ifnet *);
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 ifnet *ifp)
113 /* XXX: destroying lo0 will lead to panics. */
114 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
123 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
127 ifp = if_alloc(IFT_LOOP);
131 if_initname(ifp, loname, unit);
133 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
134 ifp->if_ioctl = loioctl;
135 ifp->if_output = looutput;
136 ifp->if_snd.ifq_maxlen = ifqmaxlen;
137 ifp->if_capabilities = ifp->if_capenable =
138 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
139 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
141 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
149 vnet_loif_init(const void *unused __unused)
153 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
155 V_lo_cloner = lo_cloner;
157 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
161 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
162 vnet_loif_init, NULL);
166 vnet_loif_uninit(const void *unused __unused)
169 if_clone_detach(V_lo_cloner);
172 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
173 vnet_loif_uninit, NULL);
177 loop_modevent(module_t mod, int type, void *data)
185 printf("loop module unload - not possible for this module type\n");
194 static moduledata_t loop_mod = {
200 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
203 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
211 M_ASSERTPKTHDR(m); /* check if we have the packet header */
214 error = mac_ifnet_check_transmit(ifp, m);
221 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
223 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
226 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
227 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
233 /* BPF writes need to be handled specially. */
234 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
235 bcopy(dst->sa_data, &af, sizeof(af));
237 af = RO_GET_FAMILY(ro, dst);
242 if (ifp->if_capenable & IFCAP_RXCSUM) {
243 m->m_pkthdr.csum_data = 0xffff;
244 m->m_pkthdr.csum_flags = LO_CSUM_SET;
246 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
251 * XXX-BZ for now always claim the checksum is good despite
252 * any interface flags. This is a workaround for 9.1-R and
253 * a proper solution ought to be sought later.
255 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
256 m->m_pkthdr.csum_data = 0xffff;
257 m->m_pkthdr.csum_flags = LO_CSUM_SET;
260 m->m_pkthdr.csum_data = 0xffff;
261 m->m_pkthdr.csum_flags = LO_CSUM_SET;
263 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
266 printf("looutput: af=%d unexpected\n", af);
268 return (EAFNOSUPPORT);
271 return (if_simloop(ifp, m, af, 0));
277 * This function is to support software emulation of hardware loopback,
278 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
279 * hear their own broadcasts, we create a copy of the packet that we
280 * would normally receive via a hardware loopback.
282 * This function expects the packet to include the media header of length hlen.
285 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
290 m_tag_delete_nonpersistent(m);
291 m->m_pkthdr.rcvif = ifp;
294 mac_ifnet_create_mbuf(ifp, m);
298 * Let BPF see incoming packet in the following manner:
299 * - Emulated packet loopback for a simplex interface
300 * (net/if_ethersubr.c)
301 * -> passes it to ifp's BPF
302 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
303 * -> not passes it to any BPF
304 * - Normal packet loopback from myself to myself (net/if_loop.c)
305 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
308 if (bpf_peers_present(ifp->if_bpf)) {
309 bpf_mtap(ifp->if_bpf, m);
312 if (bpf_peers_present(V_loif->if_bpf)) {
313 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
314 /* XXX beware sizeof(af) != 4 */
318 * We need to prepend the address family.
320 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
325 /* Strip away media header */
328 #ifndef __NO_STRICT_ALIGNMENT
330 * Some archs do not like unaligned data, so
331 * we move data down in the first mbuf.
333 if (mtod(m, vm_offset_t) & 3) {
334 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
336 (char *)(mtod(m, vm_offset_t)
337 - (mtod(m, vm_offset_t) & 3)),
339 m->m_data -= (mtod(m,vm_offset_t) & 3);
344 /* Deliver to upper layer protocol */
353 m->m_flags |= M_LOOP;
358 printf("if_simloop: can't handle af=%d\n", af);
360 return (EAFNOSUPPORT);
362 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
363 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
364 netisr_queue(isr, m); /* mbuf is free'd on failure. */
369 * Process an ioctl request.
373 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
375 struct ifreq *ifr = (struct ifreq *)data;
380 ifp->if_flags |= IFF_UP;
381 ifp->if_drv_flags |= IFF_DRV_RUNNING;
382 if_link_state_change(ifp, LINK_STATE_UP);
384 * Everything else is done at a higher level.
391 error = EAFNOSUPPORT; /* XXX */
394 switch (ifr->ifr_addr.sa_family) {
405 error = EAFNOSUPPORT;
411 ifp->if_mtu = ifr->ifr_mtu;
415 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
416 LINK_STATE_UP: LINK_STATE_DOWN);
420 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
421 if ((mask & IFCAP_RXCSUM) != 0)
422 ifp->if_capenable ^= IFCAP_RXCSUM;
423 if ((mask & IFCAP_TXCSUM) != 0)
424 ifp->if_capenable ^= IFCAP_TXCSUM;
425 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
427 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
433 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
435 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
441 ifp->if_hwassist = 0;
442 if (ifp->if_capenable & IFCAP_TXCSUM)
443 ifp->if_hwassist = LO_CSUM_FEATURES;
445 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
446 ifp->if_hwassist |= LO_CSUM_FEATURES6;