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29 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
34 * Discard interface driver for protocol testing and timing.
35 * Mimics an Ethernet device so that VLANs can be attached to it etc.
38 #include <sys/param.h> /* types, important constants */
39 #include <sys/kernel.h> /* SYSINIT for load-time initializations */
40 #include <sys/malloc.h> /* malloc(9) */
41 #include <sys/module.h> /* module(9) */
42 #include <sys/mbuf.h> /* mbuf(9) */
43 #include <sys/socket.h> /* struct ifreq */
44 #include <sys/sockio.h> /* socket ioctl's */
45 /* #include <sys/systm.h> if you need printf(9) or other all-purpose globals */
47 #include <net/bpf.h> /* bpf(9) */
48 #include <net/ethernet.h> /* Ethernet related constants and types */
50 #include <net/if_var.h> /* basic part of ifnet(9) */
51 #include <net/if_clone.h> /* network interface cloning */
52 #include <net/if_types.h> /* IFT_ETHER and friends */
53 #include <net/if_var.h> /* kernel-only part of ifnet(9) */
56 static const char edscname[] = "edsc";
59 * Software configuration of an interface specific to this device type.
62 struct ifnet *sc_ifp; /* ptr to generic interface configuration */
65 * A non-null driver can keep various things here, for instance,
66 * the hardware revision, cached values of write-only registers, etc.
71 * Attach to the interface cloning framework.
73 static VNET_DEFINE(struct if_clone *, edsc_cloner);
74 #define V_edsc_cloner VNET(edsc_cloner)
75 static int edsc_clone_create(struct if_clone *, int, caddr_t);
76 static void edsc_clone_destroy(struct ifnet *);
79 * Interface driver methods.
81 static void edsc_init(void *dummy);
82 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */
83 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data);
84 static void edsc_start(struct ifnet *ifp);
87 * We'll allocate softc instances from this.
89 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface");
92 * Create an interface instance.
95 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
97 struct edsc_softc *sc;
99 static u_char eaddr[ETHER_ADDR_LEN]; /* 0:0:0:0:0:0 */
102 * Allocate soft and ifnet structures. Link each to the other.
104 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO);
105 ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
114 * Get a name for this particular interface in its ifnet structure.
116 if_initname(ifp, edscname, unit);
119 * Typical Ethernet interface flags: we can do broadcast and
120 * multicast but can't hear our own broadcasts or multicasts.
122 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX;
125 * We can pretent we have the whole set of hardware features
126 * because we just discard all packets we get from the upper layer.
127 * However, the features are disabled initially. They can be
128 * enabled via edsc_ioctl() when needed.
130 ifp->if_capabilities =
131 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM |
132 IFCAP_HWCSUM | IFCAP_TSO |
134 ifp->if_capenable = 0;
137 * Set the interface driver methods.
139 ifp->if_init = edsc_init;
140 /* ifp->if_input = edsc_input; */
141 ifp->if_ioctl = edsc_ioctl;
142 ifp->if_start = edsc_start;
145 * Set the maximum output queue length from the global parameter.
147 ifp->if_snd.ifq_maxlen = ifqmaxlen;
150 * Do ifnet initializations common to all Ethernet drivers
151 * and attach to the network interface framework.
152 * TODO: Pick a non-zero link level address.
154 ether_ifattach(ifp, eaddr);
157 * Now we can mark the interface as running, i.e., ready
160 ifp->if_drv_flags |= IFF_DRV_RUNNING;
166 * Destroy an interface instance.
169 edsc_clone_destroy(struct ifnet *ifp)
171 struct edsc_softc *sc = ifp->if_softc;
174 * Detach from the network interface framework.
179 * Free memory occupied by ifnet and softc.
186 * This method is invoked from ether_ioctl() when it's time
187 * to bring up the hardware.
190 edsc_init(void *dummy)
192 #if 0 /* what a hardware driver would do here... */
193 struct edsc_soft *sc = (struct edsc_softc *)dummy;
194 struct ifnet *ifp = sc->sc_ifp;
201 * Network interfaces are controlled via the ioctl(2) syscall.
204 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
206 struct ifreq *ifr = (struct ifreq *)data;
212 * Just turn on any capabilities requested.
213 * The generic ifioctl() function has already made sure
214 * that they are supported, i.e., set in if_capabilities.
216 ifp->if_capenable = ifr->ifr_reqcap;
219 * A h/w driver would need to analyze the requested
220 * bits and program the hardware, e.g.:
222 mask = ifp->if_capenable ^ ifr->ifr_reqcap;
224 if (mask & IFCAP_VLAN_HWTAGGING) {
225 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING;
227 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING)
237 * Offload the rest onto the common Ethernet handler.
239 return (ether_ioctl(ifp, cmd, data));
246 * Process the output queue.
249 edsc_start(struct ifnet *ifp)
254 * A hardware interface driver can set IFF_DRV_OACTIVE
255 * in ifp->if_drv_flags:
257 * ifp->if_drv_flags |= IFF_DRV_OACTIVE;
259 * to prevent if_start from being invoked again while the
260 * transmission is under way. The flag is to protect the
261 * device's transmitter, not the method itself. The output
262 * queue is locked and several threads can process it in
263 * parallel safely, so the driver can use other means to
264 * serialize access to the transmitter.
266 * If using IFF_DRV_OACTIVE, the driver should clear the flag
267 * not earlier than the current transmission is complete, e.g.,
268 * upon an interrupt from the device, not just before returning
269 * from if_start. This method merely starts the transmission,
270 * which may proceed asynchronously.
274 * We loop getting packets from the queue until it's empty.
275 * A h/w driver would loop until the device can accept more
276 * data into its buffer, or while there are free transmit
277 * descriptors, or whatever.
281 * Try to dequeue one packet. Stop if the queue is empty.
282 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded.
284 IFQ_DEQUEUE(&ifp->if_snd, m);
289 * Let bpf(9) at the packet.
294 * Update the interface counters.
296 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
297 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
300 * Finally, just drop the packet.
301 * TODO: Reply to ARP requests unless IFF_NOARP is set.
307 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
308 * would be here only if the transmission were synchronous.
313 vnet_edsc_init(const void *unused __unused)
317 * Connect to the network interface cloning framework.
318 * The last argument is the number of units to be created
319 * from the outset. It's also the minimum number of units
320 * allowed. We don't want any units created as soon as the
323 V_edsc_cloner = if_clone_simple(edscname, edsc_clone_create,
324 edsc_clone_destroy, 0);
326 VNET_SYSINIT(vnet_edsc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
327 vnet_edsc_init, NULL);
330 vnet_edsc_uninit(const void *unused __unused)
334 * Disconnect from the cloning framework.
335 * Existing interfaces will be disposed of properly.
337 if_clone_detach(V_edsc_cloner);
339 VNET_SYSUNINIT(vnet_edsc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
340 vnet_edsc_uninit, NULL);
343 * This function provides handlers for module events, namely load and unload.
346 edsc_modevent(module_t mod, int type, void *data)
355 * There are other event types, but we don't handle them.
363 static moduledata_t edsc_mod = {
364 "if_edsc", /* name */
365 edsc_modevent, /* event handler */
366 NULL /* additional data */
369 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);