1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following edsclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following edsclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE EDSCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Discard interface driver for protocol testing and timing. 34 * Mimics an Ethernet device so that VLANs can be attached to it etc. 35 */ 36 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 */ 45 46 #include <net/bpf.h> /* bpf(9) */ 47 #include <net/ethernet.h> /* Ethernet related constants and types */ 48 #include <net/if.h> 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 */ 53 #include <net/vnet.h> 54 55 static const char edscname[] = "edsc"; 56 57 /* 58 * Software configuration of an interface specific to this device type. 59 */ 60 struct edsc_softc { 61 struct ifnet *sc_ifp; /* ptr to generic interface configuration */ 62 63 /* 64 * A non-null driver can keep various things here, for instance, 65 * the hardware revision, cached values of write-only registers, etc. 66 */ 67 }; 68 69 /* 70 * Attach to the interface cloning framework. 71 */ 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 *); 76 77 /* 78 * Interface driver methods. 79 */ 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); 84 85 /* 86 * We'll allocate softc instances from this. 87 */ 88 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface"); 89 90 /* 91 * Create an interface instance. 92 */ 93 static int 94 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 95 { 96 struct edsc_softc *sc; 97 struct ifnet *ifp; 98 struct ether_addr eaddr; 99 100 /* 101 * Allocate soft and ifnet structures. Link each to the other. 102 */ 103 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO); 104 ifp = sc->sc_ifp = if_alloc(IFT_ETHER); 105 ifp->if_softc = sc; 106 107 /* 108 * Get a name for this particular interface in its ifnet structure. 109 */ 110 if_initname(ifp, edscname, unit); 111 112 /* 113 * Typical Ethernet interface flags: we can do broadcast and 114 * multicast but can't hear our own broadcasts or multicasts. 115 */ 116 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX; 117 118 /* 119 * We can pretent we have the whole set of hardware features 120 * because we just discard all packets we get from the upper layer. 121 * However, the features are disabled initially. They can be 122 * enabled via edsc_ioctl() when needed. 123 */ 124 ifp->if_capabilities = 125 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM | 126 IFCAP_HWCSUM | IFCAP_TSO | 127 IFCAP_JUMBO_MTU; 128 ifp->if_capenable = 0; 129 130 /* 131 * Set the interface driver methods. 132 */ 133 ifp->if_init = edsc_init; 134 /* ifp->if_input = edsc_input; */ 135 ifp->if_ioctl = edsc_ioctl; 136 ifp->if_start = edsc_start; 137 138 /* 139 * Set the maximum output queue length from the global parameter. 140 */ 141 ifp->if_snd.ifq_maxlen = ifqmaxlen; 142 143 /* 144 * Generate an arbitrary MAC address for the cloned interface. 145 */ 146 ether_gen_addr(ifp, &eaddr); 147 148 /* 149 * Do ifnet initializations common to all Ethernet drivers 150 * and attach to the network interface framework. 151 */ 152 ether_ifattach(ifp, eaddr.octet); 153 154 /* 155 * Now we can mark the interface as running, i.e., ready 156 * for operation. 157 */ 158 ifp->if_drv_flags |= IFF_DRV_RUNNING; 159 160 return (0); 161 } 162 163 /* 164 * Destroy an interface instance. 165 */ 166 static void 167 edsc_clone_destroy(struct ifnet *ifp) 168 { 169 struct edsc_softc *sc = ifp->if_softc; 170 171 /* 172 * Detach from the network interface framework. 173 */ 174 ether_ifdetach(ifp); 175 176 /* 177 * Free memory occupied by ifnet and softc. 178 */ 179 if_free(ifp); 180 free(sc, M_EDSC); 181 } 182 183 /* 184 * This method is invoked from ether_ioctl() when it's time 185 * to bring up the hardware. 186 */ 187 static void 188 edsc_init(void *dummy) 189 { 190 #if 0 /* what a hardware driver would do here... */ 191 struct edsc_soft *sc = (struct edsc_softc *)dummy; 192 struct ifnet *ifp = sc->sc_ifp; 193 194 /* blah-blah-blah */ 195 #endif 196 } 197 198 /* 199 * Network interfaces are controlled via the ioctl(2) syscall. 200 */ 201 static int 202 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 203 { 204 struct ifreq *ifr = (struct ifreq *)data; 205 206 switch (cmd) { 207 case SIOCSIFCAP: 208 #if 1 209 /* 210 * Just turn on any capabilities requested. 211 * The generic ifioctl() function has already made sure 212 * that they are supported, i.e., set in if_capabilities. 213 */ 214 ifp->if_capenable = ifr->ifr_reqcap; 215 #else 216 /* 217 * A h/w driver would need to analyze the requested 218 * bits and program the hardware, e.g.: 219 */ 220 mask = ifp->if_capenable ^ ifr->ifr_reqcap; 221 222 if (mask & IFCAP_VLAN_HWTAGGING) { 223 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING; 224 225 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING) 226 /* blah-blah-blah */ 227 else 228 /* etc-etc-etc */ 229 } 230 #endif 231 break; 232 233 default: 234 /* 235 * Offload the rest onto the common Ethernet handler. 236 */ 237 return (ether_ioctl(ifp, cmd, data)); 238 } 239 240 return (0); 241 } 242 243 /* 244 * Process the output queue. 245 */ 246 static void 247 edsc_start(struct ifnet *ifp) 248 { 249 struct mbuf *m; 250 251 /* 252 * A hardware interface driver can set IFF_DRV_OACTIVE 253 * in ifp->if_drv_flags: 254 * 255 * ifp->if_drv_flags |= IFF_DRV_OACTIVE; 256 * 257 * to prevent if_start from being invoked again while the 258 * transmission is under way. The flag is to protect the 259 * device's transmitter, not the method itself. The output 260 * queue is locked and several threads can process it in 261 * parallel safely, so the driver can use other means to 262 * serialize access to the transmitter. 263 * 264 * If using IFF_DRV_OACTIVE, the driver should clear the flag 265 * not earlier than the current transmission is complete, e.g., 266 * upon an interrupt from the device, not just before returning 267 * from if_start. This method merely starts the transmission, 268 * which may proceed asynchronously. 269 */ 270 271 /* 272 * We loop getting packets from the queue until it's empty. 273 * A h/w driver would loop until the device can accept more 274 * data into its buffer, or while there are free transmit 275 * descriptors, or whatever. 276 */ 277 for (;;) { 278 /* 279 * Try to dequeue one packet. Stop if the queue is empty. 280 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded. 281 */ 282 IFQ_DEQUEUE(&ifp->if_snd, m); 283 if (m == NULL) 284 break; 285 286 /* 287 * Let bpf(9) at the packet. 288 */ 289 BPF_MTAP(ifp, m); 290 291 /* 292 * Update the interface counters. 293 */ 294 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len); 295 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 296 297 /* 298 * Finally, just drop the packet. 299 * TODO: Reply to ARP requests unless IFF_NOARP is set. 300 */ 301 m_freem(m); 302 } 303 304 /* 305 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE; 306 * would be here only if the transmission were synchronous. 307 */ 308 } 309 310 static void 311 vnet_edsc_init(const void *unused __unused) 312 { 313 314 /* 315 * Connect to the network interface cloning framework. 316 * The last argument is the number of units to be created 317 * from the outset. It's also the minimum number of units 318 * allowed. We don't want any units created as soon as the 319 * driver is loaded. 320 */ 321 V_edsc_cloner = if_clone_simple(edscname, edsc_clone_create, 322 edsc_clone_destroy, 0); 323 } 324 VNET_SYSINIT(vnet_edsc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY, 325 vnet_edsc_init, NULL); 326 327 static void 328 vnet_edsc_uninit(const void *unused __unused) 329 { 330 331 /* 332 * Disconnect from the cloning framework. 333 * Existing interfaces will be disposed of properly. 334 */ 335 if_clone_detach(V_edsc_cloner); 336 } 337 VNET_SYSUNINIT(vnet_edsc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY, 338 vnet_edsc_uninit, NULL); 339 340 /* 341 * This function provides handlers for module events, namely load and unload. 342 */ 343 static int 344 edsc_modevent(module_t mod, int type, void *data) 345 { 346 347 switch (type) { 348 case MOD_LOAD: 349 case MOD_UNLOAD: 350 break; 351 default: 352 /* 353 * There are other event types, but we don't handle them. 354 * See module(9). 355 */ 356 return (EOPNOTSUPP); 357 } 358 return (0); 359 } 360 361 static moduledata_t edsc_mod = { 362 "if_edsc", /* name */ 363 edsc_modevent, /* event handler */ 364 NULL /* additional data */ 365 }; 366 367 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 368