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33 * @(#)if_loop.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/net/if_loop.c,v 1.47.2.9 2004/02/08 08:40:24 silby Exp $
35 * $DragonFly: src/sys/net/if_loop.c,v 1.24 2008/09/06 05:46:47 sephe Exp $
39 * Loopback interface driver for protocol testing and timing.
43 #include "opt_atalk.h"
45 #include "opt_inet6.h"
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
52 #include <sys/socket.h>
53 #include <sys/sockio.h>
56 #include <net/if_types.h>
57 #include <net/ifq_var.h>
58 #include <net/netisr.h>
59 #include <net/route.h>
61 #include <net/bpfdesc.h>
64 #include <netinet/in.h>
65 #include <netinet/in_var.h>
69 #include <netproto/ipx/ipx.h>
70 #include <netproto/ipx/ipx_if.h>
75 #include <netinet/in.h>
77 #include <netinet6/in6_var.h>
78 #include <netinet/ip6.h>
83 #include <netns/ns_if.h>
87 #include <netproto/atalk/at.h>
88 #include <netproto/atalk/at_var.h>
91 int loioctl (struct ifnet *, u_long, caddr_t, struct ucred *);
92 static void lortrequest (int, struct rtentry *, struct rt_addrinfo *);
94 static void loopattach (void *);
96 static void lo_altqstart(struct ifnet *);
98 PSEUDO_SET(loopattach, if_loop);
100 int looutput (struct ifnet *ifp,
101 struct mbuf *m, struct sockaddr *dst, struct rtentry *rt);
104 #define LOMTU (1024+512)
105 #elif defined(LARGE_LOMTU)
111 #define LO_CSUM_FEATURES (CSUM_IP | CSUM_UDP | CSUM_TCP)
113 struct ifnet loif[NLOOP];
117 loopattach(void *dummy)
122 for (i = 0, ifp = loif; i < NLOOP; i++, ifp++) {
123 if_initname(ifp, "lo", i);
125 ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
126 ifp->if_capabilities = IFCAP_HWCSUM;
127 ifp->if_hwassist = LO_CSUM_FEATURES;
128 ifp->if_capenable = ifp->if_capabilities;
129 ifp->if_ioctl = loioctl;
130 ifp->if_output = looutput;
131 ifp->if_type = IFT_LOOP;
132 ifq_set_maxlen(&ifp->if_snd, ifqmaxlen);
133 ifq_set_ready(&ifp->if_snd);
135 ifp->if_start = lo_altqstart;
137 if_attach(ifp, NULL);
138 bpfattach(ifp, DLT_NULL, sizeof(u_int));
143 looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
148 if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
150 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
151 rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
155 ifp->if_obytes += m->m_pkthdr.len;
157 switch (dst->sa_family) {
165 kprintf("looutput: af=%d unexpected\n", dst->sa_family);
167 return (EAFNOSUPPORT);
171 if (ifp->if_capenable & IFCAP_RXCSUM) {
174 if (m->m_pkthdr.csum_flags & CSUM_IP)
175 csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
176 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
177 csum_flags |= (CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
179 m->m_pkthdr.csum_flags |= csum_flags;
180 if (csum_flags & CSUM_DATA_VALID)
181 m->m_pkthdr.csum_data = 0xffff;
183 return (if_simloop(ifp, m, dst->sa_family, 0));
189 * This function is to support software emulation of hardware loopback,
190 * i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
191 * hear their own broadcasts, we create a copy of the packet that we
192 * would normally receive via a hardware loopback.
194 * This function expects the packet to include the media header of length hlen.
197 if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
201 KASSERT((m->m_flags & M_PKTHDR) != 0, ("if_simloop: no HDR"));
202 m->m_pkthdr.rcvif = ifp;
204 /* BPF write needs to be handled specially */
205 if (af == AF_UNSPEC) {
206 KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
207 af = *(mtod(m, int *));
208 m->m_len -= sizeof(int);
209 m->m_pkthdr.len -= sizeof(int);
210 m->m_data += sizeof(int);
214 if (ifp->if_bpf->bif_dlt == DLT_NULL) {
215 uint32_t bpf_af = (uint32_t)af;
216 bpf_ptap(ifp->if_bpf, m, &bpf_af, 4);
219 bpf_mtap(ifp->if_bpf, m);
223 /* Strip away media header */
229 * altq for loop is just for debugging.
230 * only used when called for loop interface (not for
231 * a simplex interface).
233 if (ifq_is_enabled(&ifp->if_snd) && ifp->if_start == lo_altqstart) {
234 struct altq_pktattr pktattr;
239 * if the queueing discipline needs packet classification,
240 * do it before prepending link headers.
242 ifq_classify(&ifp->if_snd, m, af, &pktattr);
244 M_PREPEND(m, sizeof(int32_t), MB_DONTWAIT);
247 afp = mtod(m, int32_t *);
251 * A critical section is needed for subsystems protected by
252 * the MP lock, and the serializer is assumed to already
253 * be held for MPSAFE subsystems.
256 error = ifq_enqueue(&ifp->if_snd, m, &pktattr);
257 lwkt_serialize_enter(ifp->if_serializer);
259 lwkt_serialize_exit(ifp->if_serializer);
265 /* Deliver to upper layer protocol */
274 m->m_flags |= M_LOOP;
294 kprintf("if_simloop: can't handle af=%d\n", af);
296 return (EAFNOSUPPORT);
300 ifp->if_ibytes += m->m_pkthdr.len;
301 netisr_queue(isr, m);
307 lo_altqstart(struct ifnet *ifp)
315 m = ifq_dequeue(&ifp->if_snd, NULL);
320 afp = mtod(m, int32_t *);
322 m_adj(m, sizeof(int32_t));
332 m->m_flags |= M_LOOP;
357 kprintf("lo_altqstart: can't handle af%d\n", af);
363 ifp->if_ibytes += m->m_pkthdr.len;
364 netisr_queue(isr, m);
371 lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
374 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
376 * For optimal performance, the send and receive buffers
377 * should be at least twice the MTU plus a little more for
380 rt->rt_rmx.rmx_recvpipe = rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
385 * Process an ioctl request.
389 loioctl(struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
392 struct ifreq *ifr = (struct ifreq *)data;
397 ifp->if_flags |= IFF_UP | IFF_RUNNING;
398 ifa = (struct ifaddr *)data;
399 ifa->ifa_rtrequest = lortrequest;
401 * Everything else is done at a higher level.
408 error = EAFNOSUPPORT; /* XXX */
411 switch (ifr->ifr_addr.sa_family) {
423 error = EAFNOSUPPORT;
429 ifp->if_mtu = ifr->ifr_mtu;
436 mask = (ifr->ifr_reqcap ^ ifp->if_capenable) & IFCAP_HWCSUM;
438 ifp->if_capenable ^= mask;
439 if (IFCAP_TXCSUM & ifp->if_capenable)
440 ifp->if_hwassist = LO_CSUM_FEATURES;
442 ifp->if_hwassist = 0;