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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_clone.h>
57 #include <net/if_types.h>
58 #include <net/netisr.h>
59 #include <net/route.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
70 #include <netinet/in.h>
72 #include <netinet6/in6_var.h>
73 #include <netinet/ip6.h>
76 #include <security/mac/mac_framework.h>
79 #define LOMTU (1024+512)
80 #elif defined(LARGE_LOMTU)
86 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
87 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
88 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
90 CSUM_IP_CHECKED | CSUM_IP_VALID | \
93 int loioctl(struct ifnet *, u_long, caddr_t);
94 int looutput(struct ifnet *ifp, struct mbuf *m,
95 const struct sockaddr *dst, struct route *ro);
96 static int lo_clone_create(struct if_clone *, int, caddr_t);
97 static void lo_clone_destroy(struct ifnet *);
99 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
102 VNET_DEFINE_STATIC(struct if_clone *, lo_cloner);
103 #define V_lo_cloner VNET(lo_cloner)
106 static struct if_clone *lo_cloner;
107 static const char loname[] = "lo";
110 lo_clone_destroy(struct ifnet *ifp)
114 /* XXX: destroying lo0 will lead to panics. */
115 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
124 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
128 ifp = if_alloc(IFT_LOOP);
132 if_initname(ifp, loname, unit);
134 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
135 ifp->if_ioctl = loioctl;
136 ifp->if_output = looutput;
137 ifp->if_snd.ifq_maxlen = ifqmaxlen;
138 ifp->if_capabilities = ifp->if_capenable =
139 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6 | IFCAP_LINKSTATE;
140 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
142 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
150 vnet_loif_init(const void *unused __unused)
154 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
156 V_lo_cloner = lo_cloner;
158 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
162 VNET_SYSINIT(vnet_loif_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
163 vnet_loif_init, NULL);
167 vnet_loif_uninit(const void *unused __unused)
170 if_clone_detach(V_lo_cloner);
173 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_INIT_IF, SI_ORDER_SECOND,
174 vnet_loif_uninit, NULL);
178 loop_modevent(module_t mod, int type, void *data)
186 printf("loop module unload - not possible for this module type\n");
195 static moduledata_t loop_mod = {
201 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
204 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
212 M_ASSERTPKTHDR(m); /* check if we have the packet header */
215 error = mac_ifnet_check_transmit(ifp, m);
222 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
224 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
227 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
228 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
234 /* BPF writes need to be handled specially. */
235 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
236 bcopy(dst->sa_data, &af, sizeof(af));
243 if (ifp->if_capenable & IFCAP_RXCSUM) {
244 m->m_pkthdr.csum_data = 0xffff;
245 m->m_pkthdr.csum_flags = LO_CSUM_SET;
247 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
252 * XXX-BZ for now always claim the checksum is good despite
253 * any interface flags. This is a workaround for 9.1-R and
254 * a proper solution ought to be sought later.
256 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
257 m->m_pkthdr.csum_data = 0xffff;
258 m->m_pkthdr.csum_flags = LO_CSUM_SET;
261 m->m_pkthdr.csum_data = 0xffff;
262 m->m_pkthdr.csum_flags = LO_CSUM_SET;
264 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
267 printf("looutput: af=%d unexpected\n", af);
269 return (EAFNOSUPPORT);
272 return (if_simloop(ifp, m, af, 0));
278 * This function is to support software emulation of hardware loopback,
279 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
280 * hear their own broadcasts, we create a copy of the packet that we
281 * would normally receive via a hardware loopback.
283 * This function expects the packet to include the media header of length hlen.
286 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
291 m_tag_delete_nonpersistent(m);
292 m->m_pkthdr.rcvif = ifp;
295 mac_ifnet_create_mbuf(ifp, m);
299 * Let BPF see incoming packet in the following manner:
300 * - Emulated packet loopback for a simplex interface
301 * (net/if_ethersubr.c)
302 * -> passes it to ifp's BPF
303 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
304 * -> not passes it to any BPF
305 * - Normal packet loopback from myself to myself (net/if_loop.c)
306 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
309 if (bpf_peers_present(ifp->if_bpf)) {
310 bpf_mtap(ifp->if_bpf, m);
313 if (bpf_peers_present(V_loif->if_bpf)) {
314 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
315 /* XXX beware sizeof(af) != 4 */
319 * We need to prepend the address family.
321 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
326 /* Strip away media header */
329 #ifndef __NO_STRICT_ALIGNMENT
331 * Some archs do not like unaligned data, so
332 * we move data down in the first mbuf.
334 if (mtod(m, vm_offset_t) & 3) {
335 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
337 (char *)(mtod(m, vm_offset_t)
338 - (mtod(m, vm_offset_t) & 3)),
340 m->m_data -= (mtod(m,vm_offset_t) & 3);
345 /* Deliver to upper layer protocol */
354 m->m_flags |= M_LOOP;
359 printf("if_simloop: can't handle af=%d\n", af);
361 return (EAFNOSUPPORT);
363 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
364 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
365 netisr_queue(isr, m); /* mbuf is free'd on failure. */
370 * Process an ioctl request.
374 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
376 struct ifreq *ifr = (struct ifreq *)data;
381 ifp->if_flags |= IFF_UP;
382 ifp->if_drv_flags |= IFF_DRV_RUNNING;
383 if_link_state_change(ifp, LINK_STATE_UP);
385 * Everything else is done at a higher level.
392 error = EAFNOSUPPORT; /* XXX */
395 switch (ifr->ifr_addr.sa_family) {
407 error = EAFNOSUPPORT;
413 ifp->if_mtu = ifr->ifr_mtu;
417 if_link_state_change(ifp, (ifp->if_flags & IFF_UP) ?
418 LINK_STATE_UP: LINK_STATE_DOWN);
422 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
423 if ((mask & IFCAP_RXCSUM) != 0)
424 ifp->if_capenable ^= IFCAP_RXCSUM;
425 if ((mask & IFCAP_TXCSUM) != 0)
426 ifp->if_capenable ^= IFCAP_TXCSUM;
427 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
429 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
435 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
437 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
443 ifp->if_hwassist = 0;
444 if (ifp->if_capenable & IFCAP_TXCSUM)
445 ifp->if_hwassist = LO_CSUM_FEATURES;
447 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
448 ifp->if_hwassist |= LO_CSUM_FEATURES6;