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31 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
35 * Discard interface driver for protocol testing and timing.
36 * Mimics an Ethernet device so that VLANs can be attached to it etc.
39 #include <sys/param.h> /* types, important constants */
40 #include <sys/kernel.h> /* SYSINIT for load-time initializations */
41 #include <sys/malloc.h> /* malloc(9) */
42 #include <sys/module.h> /* module(9) */
43 #include <sys/mbuf.h> /* mbuf(9) */
44 #include <sys/socket.h> /* struct ifreq */
45 #include <sys/sockio.h> /* socket ioctl's */
46 /* #include <sys/systm.h> if you need printf(9) or other all-purpose globals */
48 #include <net/bpf.h> /* bpf(9) */
49 #include <net/ethernet.h> /* Ethernet related constants and types */
51 #include <net/if_var.h> /* basic part of ifnet(9) */
52 #include <net/if_private.h>
53 #include <net/if_clone.h> /* network interface cloning */
54 #include <net/if_types.h> /* IFT_ETHER and friends */
57 static const char edscname[] = "edsc";
60 * Software configuration of an interface specific to this device type.
63 struct ifnet *sc_ifp; /* ptr to generic interface configuration */
66 * A non-null driver can keep various things here, for instance,
67 * the hardware revision, cached values of write-only registers, etc.
72 * Attach to the interface cloning framework.
74 VNET_DEFINE_STATIC(struct if_clone *, edsc_cloner);
75 #define V_edsc_cloner VNET(edsc_cloner)
76 static int edsc_clone_create(struct if_clone *, int, caddr_t);
77 static void edsc_clone_destroy(struct ifnet *);
80 * Interface driver methods.
82 static void edsc_init(void *dummy);
83 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */
84 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
85 static void edsc_start(struct ifnet *ifp);
88 * We'll allocate softc instances from this.
90 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface");
93 * Create an interface instance.
96 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
98 struct edsc_softc *sc;
100 struct ether_addr eaddr;
103 * Allocate soft and ifnet structures. Link each to the other.
105 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO);
106 ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
115 * Get a name for this particular interface in its ifnet structure.
117 if_initname(ifp, edscname, unit);
120 * Typical Ethernet interface flags: we can do broadcast and
121 * multicast but can't hear our own broadcasts or multicasts.
123 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX;
126 * We can pretent we have the whole set of hardware features
127 * because we just discard all packets we get from the upper layer.
128 * However, the features are disabled initially. They can be
129 * enabled via edsc_ioctl() when needed.
131 ifp->if_capabilities =
132 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM |
133 IFCAP_HWCSUM | IFCAP_TSO |
135 ifp->if_capenable = 0;
138 * Set the interface driver methods.
140 ifp->if_init = edsc_init;
141 /* ifp->if_input = edsc_input; */
142 ifp->if_ioctl = edsc_ioctl;
143 ifp->if_start = edsc_start;
146 * Set the maximum output queue length from the global parameter.
148 ifp->if_snd.ifq_maxlen = ifqmaxlen;
151 * Generate an arbitrary MAC address for the cloned interface.
153 ether_gen_addr(ifp, &eaddr);
156 * Do ifnet initializations common to all Ethernet drivers
157 * and attach to the network interface framework.
159 ether_ifattach(ifp, eaddr.octet);
162 * Now we can mark the interface as running, i.e., ready
165 ifp->if_drv_flags |= IFF_DRV_RUNNING;
171 * Destroy an interface instance.
174 edsc_clone_destroy(struct ifnet *ifp)
176 struct edsc_softc *sc = ifp->if_softc;
179 * Detach from the network interface framework.
184 * Free memory occupied by ifnet and softc.
191 * This method is invoked from ether_ioctl() when it's time
192 * to bring up the hardware.
195 edsc_init(void *dummy)
197 #if 0 /* what a hardware driver would do here... */
198 struct edsc_soft *sc = (struct edsc_softc *)dummy;
199 struct ifnet *ifp = sc->sc_ifp;
206 * Network interfaces are controlled via the ioctl(2) syscall.
209 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
211 struct ifreq *ifr = (struct ifreq *)data;
217 * Just turn on any capabilities requested.
218 * The generic ifioctl() function has already made sure
219 * that they are supported, i.e., set in if_capabilities.
221 ifp->if_capenable = ifr->ifr_reqcap;
224 * A h/w driver would need to analyze the requested
225 * bits and program the hardware, e.g.:
227 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
229 if (mask & IFCAP_VLAN_HWTAGGING) {
230 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING;
232 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING)
242 * Offload the rest onto the common Ethernet handler.
244 return (ether_ioctl(ifp, cmd, data));
251 * Process the output queue.
254 edsc_start(struct ifnet *ifp)
259 * A hardware interface driver can set IFF_DRV_OACTIVE
260 * in ifp->if_drv_flags:
262 * ifp->if_drv_flags |= IFF_DRV_OACTIVE;
264 * to prevent if_start from being invoked again while the
265 * transmission is under way. The flag is to protect the
266 * device's transmitter, not the method itself. The output
267 * queue is locked and several threads can process it in
268 * parallel safely, so the driver can use other means to
269 * serialize access to the transmitter.
271 * If using IFF_DRV_OACTIVE, the driver should clear the flag
272 * not earlier than the current transmission is complete, e.g.,
273 * upon an interrupt from the device, not just before returning
274 * from if_start. This method merely starts the transmission,
275 * which may proceed asynchronously.
279 * We loop getting packets from the queue until it's empty.
280 * A h/w driver would loop until the device can accept more
281 * data into its buffer, or while there are free transmit
282 * descriptors, or whatever.
286 * Try to dequeue one packet. Stop if the queue is empty.
287 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded.
289 IFQ_DEQUEUE(&ifp->if_snd, m);
294 * Let bpf(9) at the packet.
299 * Update the interface counters.
301 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
302 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
305 * Finally, just drop the packet.
306 * TODO: Reply to ARP requests unless IFF_NOARP is set.
312 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
313 * would be here only if the transmission were synchronous.
318 vnet_edsc_init(const void *unused __unused)
322 * Connect to the network interface cloning framework.
323 * The last argument is the number of units to be created
324 * from the outset. It's also the minimum number of units
325 * allowed. We don't want any units created as soon as the
328 V_edsc_cloner = if_clone_simple(edscname, edsc_clone_create,
329 edsc_clone_destroy, 0);
331 VNET_SYSINIT(vnet_edsc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
332 vnet_edsc_init, NULL);
335 vnet_edsc_uninit(const void *unused __unused)
339 * Disconnect from the cloning framework.
340 * Existing interfaces will be disposed of properly.
342 if_clone_detach(V_edsc_cloner);
344 VNET_SYSUNINIT(vnet_edsc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
345 vnet_edsc_uninit, NULL);
348 * This function provides handlers for module events, namely load and unload.
351 edsc_modevent(module_t mod, int type, void *data)
360 * There are other event types, but we don't handle them.
368 static moduledata_t edsc_mod = {
369 "if_edsc", /* name */
370 edsc_modevent, /* event handler */
371 NULL /* additional data */
374 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);