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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,
205 struct rtentry *rt = NULL;
210 M_ASSERTPKTHDR(m); /* check if we have the packet header */
215 error = mac_ifnet_check_transmit(ifp, m);
222 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
224 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
225 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
228 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
229 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
231 /* BPF writes need to be handled specially. */
232 if (dst->sa_family == AF_UNSPEC)
233 bcopy(dst->sa_data, &af, sizeof(af));
240 if (ifp->if_capenable & IFCAP_RXCSUM) {
241 m->m_pkthdr.csum_data = 0xffff;
242 m->m_pkthdr.csum_flags = LO_CSUM_SET;
244 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
249 * XXX-BZ for now always claim the checksum is good despite
250 * any interface flags. This is a workaround for 9.1-R and
251 * a proper solution ought to be sought later.
253 if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
254 m->m_pkthdr.csum_data = 0xffff;
255 m->m_pkthdr.csum_flags = LO_CSUM_SET;
258 m->m_pkthdr.csum_data = 0xffff;
259 m->m_pkthdr.csum_flags = LO_CSUM_SET;
261 m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
264 printf("looutput: af=%d unexpected\n", af);
266 return (EAFNOSUPPORT);
269 return (if_simloop(ifp, m, af, 0));
275 * This function is to support software emulation of hardware loopback,
276 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
277 * hear their own broadcasts, we create a copy of the packet that we
278 * would normally receive via a hardware loopback.
280 * This function expects the packet to include the media header of length hlen.
283 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
288 m_tag_delete_nonpersistent(m);
289 m->m_pkthdr.rcvif = ifp;
292 mac_ifnet_create_mbuf(ifp, m);
296 * Let BPF see incoming packet in the following manner:
297 * - Emulated packet loopback for a simplex interface
298 * (net/if_ethersubr.c)
299 * -> passes it to ifp's BPF
300 * - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
301 * -> not passes it to any BPF
302 * - Normal packet loopback from myself to myself (net/if_loop.c)
303 * -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
306 if (bpf_peers_present(ifp->if_bpf)) {
307 bpf_mtap(ifp->if_bpf, m);
310 if (bpf_peers_present(V_loif->if_bpf)) {
311 if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
312 /* XXX beware sizeof(af) != 4 */
316 * We need to prepend the address family.
318 bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
323 /* Strip away media header */
326 #ifndef __NO_STRICT_ALIGNMENT
328 * Some archs do not like unaligned data, so
329 * we move data down in the first mbuf.
331 if (mtod(m, vm_offset_t) & 3) {
332 KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
334 (char *)(mtod(m, vm_offset_t)
335 - (mtod(m, vm_offset_t) & 3)),
337 m->m_data -= (mtod(m,vm_offset_t) & 3);
342 /* Deliver to upper layer protocol */
351 m->m_flags |= M_LOOP;
356 printf("if_simloop: can't handle af=%d\n", af);
358 return (EAFNOSUPPORT);
360 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
361 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
362 netisr_queue(isr, m); /* mbuf is free'd on failure. */
367 * Process an ioctl request.
371 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
373 struct ifreq *ifr = (struct ifreq *)data;
378 ifp->if_flags |= IFF_UP;
379 ifp->if_drv_flags |= IFF_DRV_RUNNING;
381 * Everything else is done at a higher level.
388 error = EAFNOSUPPORT; /* XXX */
391 switch (ifr->ifr_addr.sa_family) {
403 error = EAFNOSUPPORT;
409 ifp->if_mtu = ifr->ifr_mtu;
416 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
417 if ((mask & IFCAP_RXCSUM) != 0)
418 ifp->if_capenable ^= IFCAP_RXCSUM;
419 if ((mask & IFCAP_TXCSUM) != 0)
420 ifp->if_capenable ^= IFCAP_TXCSUM;
421 if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
423 ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
429 if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
431 ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
437 ifp->if_hwassist = 0;
438 if (ifp->if_capenable & IFCAP_TXCSUM)
439 ifp->if_hwassist = LO_CSUM_FEATURES;
441 if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
442 ifp->if_hwassist |= LO_CSUM_FEATURES6;