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33 * Discard interface driver for protocol testing and timing.
34 * Mimics an Ethernet device so that VLANs can be attached to it etc.
37 #include <sys/param.h> /* types, important constants */
38 #include <sys/kernel.h> /* SYSINIT for load-time initializations */
39 #include <sys/malloc.h> /* malloc(9) */
40 #include <sys/module.h> /* module(9) */
41 #include <sys/mbuf.h> /* mbuf(9) */
42 #include <sys/socket.h> /* struct ifreq */
43 #include <sys/sockio.h> /* socket ioctl's */
44 /* #include <sys/systm.h> if you need printf(9) or other all-purpose globals */
46 #include <net/bpf.h> /* bpf(9) */
47 #include <net/ethernet.h> /* Ethernet related constants and types */
49 #include <net/if_var.h> /* basic part of ifnet(9) */
50 #include <net/if_private.h>
51 #include <net/if_clone.h> /* network interface cloning */
52 #include <net/if_types.h> /* IFT_ETHER and friends */
55 static const char edscname[] = "edsc";
58 * Software configuration of an interface specific to this device type.
61 struct ifnet *sc_ifp; /* ptr to generic interface configuration */
64 * A non-null driver can keep various things here, for instance,
65 * the hardware revision, cached values of write-only registers, etc.
70 * Attach to the interface cloning framework.
72 VNET_DEFINE_STATIC(struct if_clone *, edsc_cloner);
73 #define V_edsc_cloner VNET(edsc_cloner)
74 static int edsc_clone_create(struct if_clone *, int, caddr_t);
75 static void edsc_clone_destroy(struct ifnet *);
78 * Interface driver methods.
80 static void edsc_init(void *dummy);
81 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */
82 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
83 static void edsc_start(struct ifnet *ifp);
86 * We'll allocate softc instances from this.
88 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface");
91 * Create an interface instance.
94 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
96 struct edsc_softc *sc;
98 struct ether_addr eaddr;
101 * Allocate soft and ifnet structures. Link each to the other.
103 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO);
104 ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
113 * Get a name for this particular interface in its ifnet structure.
115 if_initname(ifp, edscname, unit);
118 * Typical Ethernet interface flags: we can do broadcast and
119 * multicast but can't hear our own broadcasts or multicasts.
121 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX;
124 * We can pretent we have the whole set of hardware features
125 * because we just discard all packets we get from the upper layer.
126 * However, the features are disabled initially. They can be
127 * enabled via edsc_ioctl() when needed.
129 ifp->if_capabilities =
130 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM |
131 IFCAP_HWCSUM | IFCAP_TSO |
133 ifp->if_capenable = 0;
136 * Set the interface driver methods.
138 ifp->if_init = edsc_init;
139 /* ifp->if_input = edsc_input; */
140 ifp->if_ioctl = edsc_ioctl;
141 ifp->if_start = edsc_start;
144 * Set the maximum output queue length from the global parameter.
146 ifp->if_snd.ifq_maxlen = ifqmaxlen;
149 * Generate an arbitrary MAC address for the cloned interface.
151 ether_gen_addr(ifp, &eaddr);
154 * Do ifnet initializations common to all Ethernet drivers
155 * and attach to the network interface framework.
157 ether_ifattach(ifp, eaddr.octet);
160 * Now we can mark the interface as running, i.e., ready
163 ifp->if_drv_flags |= IFF_DRV_RUNNING;
169 * Destroy an interface instance.
172 edsc_clone_destroy(struct ifnet *ifp)
174 struct edsc_softc *sc = ifp->if_softc;
177 * Detach from the network interface framework.
182 * Free memory occupied by ifnet and softc.
189 * This method is invoked from ether_ioctl() when it's time
190 * to bring up the hardware.
193 edsc_init(void *dummy)
195 #if 0 /* what a hardware driver would do here... */
196 struct edsc_soft *sc = (struct edsc_softc *)dummy;
197 struct ifnet *ifp = sc->sc_ifp;
204 * Network interfaces are controlled via the ioctl(2) syscall.
207 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
209 struct ifreq *ifr = (struct ifreq *)data;
215 * Just turn on any capabilities requested.
216 * The generic ifioctl() function has already made sure
217 * that they are supported, i.e., set in if_capabilities.
219 ifp->if_capenable = ifr->ifr_reqcap;
222 * A h/w driver would need to analyze the requested
223 * bits and program the hardware, e.g.:
225 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
227 if (mask & IFCAP_VLAN_HWTAGGING) {
228 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING;
230 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING)
240 * Offload the rest onto the common Ethernet handler.
242 return (ether_ioctl(ifp, cmd, data));
249 * Process the output queue.
252 edsc_start(struct ifnet *ifp)
257 * A hardware interface driver can set IFF_DRV_OACTIVE
258 * in ifp->if_drv_flags:
260 * ifp->if_drv_flags |= IFF_DRV_OACTIVE;
262 * to prevent if_start from being invoked again while the
263 * transmission is under way. The flag is to protect the
264 * device's transmitter, not the method itself. The output
265 * queue is locked and several threads can process it in
266 * parallel safely, so the driver can use other means to
267 * serialize access to the transmitter.
269 * If using IFF_DRV_OACTIVE, the driver should clear the flag
270 * not earlier than the current transmission is complete, e.g.,
271 * upon an interrupt from the device, not just before returning
272 * from if_start. This method merely starts the transmission,
273 * which may proceed asynchronously.
277 * We loop getting packets from the queue until it's empty.
278 * A h/w driver would loop until the device can accept more
279 * data into its buffer, or while there are free transmit
280 * descriptors, or whatever.
284 * Try to dequeue one packet. Stop if the queue is empty.
285 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded.
287 IFQ_DEQUEUE(&ifp->if_snd, m);
292 * Let bpf(9) at the packet.
297 * Update the interface counters.
299 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
300 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
303 * Finally, just drop the packet.
304 * TODO: Reply to ARP requests unless IFF_NOARP is set.
310 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
311 * would be here only if the transmission were synchronous.
316 vnet_edsc_init(const void *unused __unused)
320 * Connect to the network interface cloning framework.
321 * The last argument is the number of units to be created
322 * from the outset. It's also the minimum number of units
323 * allowed. We don't want any units created as soon as the
326 V_edsc_cloner = if_clone_simple(edscname, edsc_clone_create,
327 edsc_clone_destroy, 0);
329 VNET_SYSINIT(vnet_edsc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
330 vnet_edsc_init, NULL);
333 vnet_edsc_uninit(const void *unused __unused)
337 * Disconnect from the cloning framework.
338 * Existing interfaces will be disposed of properly.
340 if_clone_detach(V_edsc_cloner);
342 VNET_SYSUNINIT(vnet_edsc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
343 vnet_edsc_uninit, NULL);
346 * This function provides handlers for module events, namely load and unload.
349 edsc_modevent(module_t mod, int type, void *data)
358 * There are other event types, but we don't handle them.
366 static moduledata_t edsc_mod = {
367 "if_edsc", /* name */
368 edsc_modevent, /* event handler */
369 NULL /* additional data */
372 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);