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29 * @(#)if_loop.c 8.2 (Berkeley) 1/9/95
34 * Loopback interface driver for protocol testing and timing.
38 #include "opt_inet6.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
44 #include <sys/module.h>
45 #include <machine/bus.h>
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 #include <sys/sysctl.h>
52 #include <net/if_var.h>
53 #include <net/if_clone.h>
54 #include <net/if_types.h>
55 #include <net/netisr.h>
56 #include <net/route.h>
61 #include <netinet/in.h>
62 #include <netinet/in_var.h>
67 #include <netinet/in.h>
69 #include <netinet6/in6_var.h>
70 #include <netinet/ip6.h>
73 #include <security/mac/mac_framework.h>
76 #define LOMTU (1024+512)
77 #elif defined(LARGE_LOMTU)
83 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
84 #define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
85 #define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
87 CSUM_IP_CHECKED | CSUM_IP_VALID | \
90 int loioctl(struct ifnet *, u_long, caddr_t);
91 int looutput(struct ifnet *ifp, struct mbuf *m,
92 const struct sockaddr *dst, struct route *ro);
93 static int lo_clone_create(struct if_clone *, int, caddr_t);
94 static void lo_clone_destroy(struct ifnet *);
96 VNET_DEFINE(struct ifnet *, loif); /* Used externally */
99 static VNET_DEFINE(struct if_clone *, lo_cloner);
100 #define V_lo_cloner VNET(lo_cloner)
103 static struct if_clone *lo_cloner;
104 static const char loname[] = "lo";
107 lo_clone_destroy(struct ifnet *ifp)
111 /* XXX: destroying lo0 will lead to panics. */
112 KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
121 lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
125 ifp = if_alloc(IFT_LOOP);
129 if_initname(ifp, loname, unit);
131 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
132 ifp->if_ioctl = loioctl;
133 ifp->if_output = looutput;
134 ifp->if_snd.ifq_maxlen = ifqmaxlen;
135 ifp->if_capabilities = ifp->if_capenable =
136 IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
137 ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
139 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
147 vnet_loif_init(const void *unused __unused)
151 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
153 V_lo_cloner = lo_cloner;
155 lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
159 VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
160 vnet_loif_init, NULL);
164 vnet_loif_uninit(const void *unused __unused)
167 if_clone_detach(V_lo_cloner);
170 VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
171 vnet_loif_uninit, NULL);
175 loop_modevent(module_t mod, int type, void *data)
183 printf("loop module unload - not possible for this module type\n");
192 static moduledata_t loop_mod = {
198 DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
201 looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
209 M_ASSERTPKTHDR(m); /* check if we have the packet header */
212 error = mac_ifnet_check_transmit(ifp, m);
219 if (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
221 return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
224 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
225 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
227 /* BPF writes need to be handled specially. */
228 if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
229 bcopy(dst->sa_data, &af, sizeof(af));
236 if (ifp->if_capenable & IFCAP_RXCSUM) {
237 m->m_pkthdr.csum_data = 0xffff;
238 m->m_pkthdr.csum_flags = LO_CSUM_SET;
240 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
245 * XXX-BZ for now always claim the checksum is good despite
246 * any interface flags. This is a workaround for 9.1-R and
247 * a proper solution ought to be sought later.
249 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
250 m->m_pkthdr.csum_data = 0xffff;
251 m->m_pkthdr.csum_flags = LO_CSUM_SET;
254 m->m_pkthdr.csum_data = 0xffff;
255 m->m_pkthdr.csum_flags = LO_CSUM_SET;
257 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
260 printf("looutput: af=%d unexpected\n", af);
262 return (EAFNOSUPPORT);
265 return (if_simloop(ifp, m, af, 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;
352 printf("if_simloop: can't handle af=%d\n", af);
354 return (EAFNOSUPPORT);
356 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
357 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
358 netisr_queue(isr, m); /* mbuf is free'd on failure. */
363 * Process an ioctl request.
367 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
369 struct ifreq *ifr = (struct ifreq *)data;
374 ifp->if_flags |= IFF_UP;
375 ifp->if_drv_flags |= IFF_DRV_RUNNING;
377 * Everything else is done at a higher level.
384 error = EAFNOSUPPORT; /* XXX */
387 switch (ifr->ifr_addr.sa_family) {
399 error = EAFNOSUPPORT;
405 ifp->if_mtu = ifr->ifr_mtu;
412 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
413 if ((mask & IFCAP_RXCSUM) != 0)
414 ifp->if_capenable ^= IFCAP_RXCSUM;
415 if ((mask & IFCAP_TXCSUM) != 0)
416 ifp->if_capenable ^= IFCAP_TXCSUM;
417 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
419 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
425 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
427 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
433 ifp->if_hwassist = 0;
434 if (ifp->if_capenable & IFCAP_TXCSUM)
435 ifp->if_hwassist = LO_CSUM_FEATURES;
437 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
438 ifp->if_hwassist |= LO_CSUM_FEATURES6;