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 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93 32 * $FreeBSD$ 33 */ 34 35 /* 36 * Discard interface driver for protocol testing and timing. 37 * Mimics an Ethernet device so that VLANs can be attached to it etc. 38 */ 39 40 #include <sys/param.h> /* types, important constants */ 41 #include <sys/kernel.h> /* SYSINIT for load-time initializations */ 42 #include <sys/malloc.h> /* malloc(9) */ 43 #include <sys/module.h> /* module(9) */ 44 #include <sys/mbuf.h> /* mbuf(9) */ 45 #include <sys/socket.h> /* struct ifreq */ 46 #include <sys/sockio.h> /* socket ioctl's */ 47 /* #include <sys/systm.h> if you need printf(9) or other all-purpose globals */ 48 49 #include <net/bpf.h> /* bpf(9) */ 50 #include <net/ethernet.h> /* Ethernet related constants and types */ 51 #include <net/if.h> 52 #include <net/if_var.h> /* basic part of ifnet(9) */ 53 #include <net/if_private.h> 54 #include <net/if_clone.h> /* network interface cloning */ 55 #include <net/if_types.h> /* IFT_ETHER and friends */ 56 #include <net/vnet.h> 57 58 static const char edscname[] = "edsc"; 59 60 /* 61 * Software configuration of an interface specific to this device type. 62 */ 63 struct edsc_softc { 64 struct ifnet *sc_ifp; /* ptr to generic interface configuration */ 65 66 /* 67 * A non-null driver can keep various things here, for instance, 68 * the hardware revision, cached values of write-only registers, etc. 69 */ 70 }; 71 72 /* 73 * Attach to the interface cloning framework. 74 */ 75 VNET_DEFINE_STATIC(struct if_clone *, edsc_cloner); 76 #define V_edsc_cloner VNET(edsc_cloner) 77 static int edsc_clone_create(struct if_clone *, int, caddr_t); 78 static void edsc_clone_destroy(struct ifnet *); 79 80 /* 81 * Interface driver methods. 82 */ 83 static void edsc_init(void *dummy); 84 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */ 85 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data); 86 static void edsc_start(struct ifnet *ifp); 87 88 /* 89 * We'll allocate softc instances from this. 90 */ 91 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface"); 92 93 /* 94 * Create an interface instance. 95 */ 96 static int 97 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 98 { 99 struct edsc_softc *sc; 100 struct ifnet *ifp; 101 struct ether_addr eaddr; 102 103 /* 104 * Allocate soft and ifnet structures. Link each to the other. 105 */ 106 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO); 107 ifp = sc->sc_ifp = if_alloc(IFT_ETHER); 108 if (ifp == NULL) { 109 free(sc, M_EDSC); 110 return (ENOSPC); 111 } 112 113 ifp->if_softc = sc; 114 115 /* 116 * Get a name for this particular interface in its ifnet structure. 117 */ 118 if_initname(ifp, edscname, unit); 119 120 /* 121 * Typical Ethernet interface flags: we can do broadcast and 122 * multicast but can't hear our own broadcasts or multicasts. 123 */ 124 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX; 125 126 /* 127 * We can pretent we have the whole set of hardware features 128 * because we just discard all packets we get from the upper layer. 129 * However, the features are disabled initially. They can be 130 * enabled via edsc_ioctl() when needed. 131 */ 132 ifp->if_capabilities = 133 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM | 134 IFCAP_HWCSUM | IFCAP_TSO | 135 IFCAP_JUMBO_MTU; 136 ifp->if_capenable = 0; 137 138 /* 139 * Set the interface driver methods. 140 */ 141 ifp->if_init = edsc_init; 142 /* ifp->if_input = edsc_input; */ 143 ifp->if_ioctl = edsc_ioctl; 144 ifp->if_start = edsc_start; 145 146 /* 147 * Set the maximum output queue length from the global parameter. 148 */ 149 ifp->if_snd.ifq_maxlen = ifqmaxlen; 150 151 /* 152 * Generate an arbitrary MAC address for the cloned interface. 153 */ 154 ether_gen_addr(ifp, &eaddr); 155 156 /* 157 * Do ifnet initializations common to all Ethernet drivers 158 * and attach to the network interface framework. 159 */ 160 ether_ifattach(ifp, eaddr.octet); 161 162 /* 163 * Now we can mark the interface as running, i.e., ready 164 * for operation. 165 */ 166 ifp->if_drv_flags |= IFF_DRV_RUNNING; 167 168 return (0); 169 } 170 171 /* 172 * Destroy an interface instance. 173 */ 174 static void 175 edsc_clone_destroy(struct ifnet *ifp) 176 { 177 struct edsc_softc *sc = ifp->if_softc; 178 179 /* 180 * Detach from the network interface framework. 181 */ 182 ether_ifdetach(ifp); 183 184 /* 185 * Free memory occupied by ifnet and softc. 186 */ 187 if_free(ifp); 188 free(sc, M_EDSC); 189 } 190 191 /* 192 * This method is invoked from ether_ioctl() when it's time 193 * to bring up the hardware. 194 */ 195 static void 196 edsc_init(void *dummy) 197 { 198 #if 0 /* what a hardware driver would do here... */ 199 struct edsc_soft *sc = (struct edsc_softc *)dummy; 200 struct ifnet *ifp = sc->sc_ifp; 201 202 /* blah-blah-blah */ 203 #endif 204 } 205 206 /* 207 * Network interfaces are controlled via the ioctl(2) syscall. 208 */ 209 static int 210 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 211 { 212 struct ifreq *ifr = (struct ifreq *)data; 213 214 switch (cmd) { 215 case SIOCSIFCAP: 216 #if 1 217 /* 218 * Just turn on any capabilities requested. 219 * The generic ifioctl() function has already made sure 220 * that they are supported, i.e., set in if_capabilities. 221 */ 222 ifp->if_capenable = ifr->ifr_reqcap; 223 #else 224 /* 225 * A h/w driver would need to analyze the requested 226 * bits and program the hardware, e.g.: 227 */ 228 mask = ifp->if_capenable ^ ifr->ifr_reqcap; 229 230 if (mask & IFCAP_VLAN_HWTAGGING) { 231 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING; 232 233 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING) 234 /* blah-blah-blah */ 235 else 236 /* etc-etc-etc */ 237 } 238 #endif 239 break; 240 241 default: 242 /* 243 * Offload the rest onto the common Ethernet handler. 244 */ 245 return (ether_ioctl(ifp, cmd, data)); 246 } 247 248 return (0); 249 } 250 251 /* 252 * Process the output queue. 253 */ 254 static void 255 edsc_start(struct ifnet *ifp) 256 { 257 struct mbuf *m; 258 259 /* 260 * A hardware interface driver can set IFF_DRV_OACTIVE 261 * in ifp->if_drv_flags: 262 * 263 * ifp->if_drv_flags |= IFF_DRV_OACTIVE; 264 * 265 * to prevent if_start from being invoked again while the 266 * transmission is under way. The flag is to protect the 267 * device's transmitter, not the method itself. The output 268 * queue is locked and several threads can process it in 269 * parallel safely, so the driver can use other means to 270 * serialize access to the transmitter. 271 * 272 * If using IFF_DRV_OACTIVE, the driver should clear the flag 273 * not earlier than the current transmission is complete, e.g., 274 * upon an interrupt from the device, not just before returning 275 * from if_start. This method merely starts the transmission, 276 * which may proceed asynchronously. 277 */ 278 279 /* 280 * We loop getting packets from the queue until it's empty. 281 * A h/w driver would loop until the device can accept more 282 * data into its buffer, or while there are free transmit 283 * descriptors, or whatever. 284 */ 285 for (;;) { 286 /* 287 * Try to dequeue one packet. Stop if the queue is empty. 288 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded. 289 */ 290 IFQ_DEQUEUE(&ifp->if_snd, m); 291 if (m == NULL) 292 break; 293 294 /* 295 * Let bpf(9) at the packet. 296 */ 297 BPF_MTAP(ifp, m); 298 299 /* 300 * Update the interface counters. 301 */ 302 if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len); 303 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); 304 305 /* 306 * Finally, just drop the packet. 307 * TODO: Reply to ARP requests unless IFF_NOARP is set. 308 */ 309 m_freem(m); 310 } 311 312 /* 313 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE; 314 * would be here only if the transmission were synchronous. 315 */ 316 } 317 318 static void 319 vnet_edsc_init(const void *unused __unused) 320 { 321 322 /* 323 * Connect to the network interface cloning framework. 324 * The last argument is the number of units to be created 325 * from the outset. It's also the minimum number of units 326 * allowed. We don't want any units created as soon as the 327 * driver is loaded. 328 */ 329 V_edsc_cloner = if_clone_simple(edscname, edsc_clone_create, 330 edsc_clone_destroy, 0); 331 } 332 VNET_SYSINIT(vnet_edsc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY, 333 vnet_edsc_init, NULL); 334 335 static void 336 vnet_edsc_uninit(const void *unused __unused) 337 { 338 339 /* 340 * Disconnect from the cloning framework. 341 * Existing interfaces will be disposed of properly. 342 */ 343 if_clone_detach(V_edsc_cloner); 344 } 345 VNET_SYSUNINIT(vnet_edsc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY, 346 vnet_edsc_uninit, NULL); 347 348 /* 349 * This function provides handlers for module events, namely load and unload. 350 */ 351 static int 352 edsc_modevent(module_t mod, int type, void *data) 353 { 354 355 switch (type) { 356 case MOD_LOAD: 357 case MOD_UNLOAD: 358 break; 359 default: 360 /* 361 * There are other event types, but we don't handle them. 362 * See module(9). 363 */ 364 return (EOPNOTSUPP); 365 } 366 return (0); 367 } 368 369 static moduledata_t edsc_mod = { 370 "if_edsc", /* name */ 371 edsc_modevent, /* event handler */ 372 NULL /* additional data */ 373 }; 374 375 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 376