1 /*- 2 * Copyright (c) 1982, 1986, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following edsclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following edsclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE EDSCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93 30 * $FreeBSD$ 31 */ 32 33 /* 34 * Discard interface driver for protocol testing and timing. 35 * Mimics an Ethernet device so that VLANs can be attached to it etc. 36 */ 37 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 */ 46 47 #include <net/bpf.h> /* bpf(9) */ 48 #include <net/ethernet.h> /* Ethernet related constants and types */ 49 #include <net/if.h> /* basic part of ifnet(9) */ 50 #include <net/if_clone.h> /* network interface cloning */ 51 #include <net/if_types.h> /* IFT_ETHER and friends */ 52 #include <net/if_var.h> /* kernel-only part of ifnet(9) */ 53 54 /* 55 * Software configuration of an interface specific to this device type. 56 */ 57 struct edsc_softc { 58 struct ifnet *sc_ifp; /* ptr to generic interface configuration */ 59 60 /* 61 * A non-null driver can keep various things here, for instance, 62 * the hardware revision, cached values of write-only registers, etc. 63 */ 64 }; 65 66 /* 67 * Simple cloning methods. 68 * IFC_SIMPLE_DECLARE() expects precisely these names. 69 */ 70 static int edsc_clone_create(struct if_clone *, int, caddr_t); 71 static void edsc_clone_destroy(struct ifnet *); 72 73 /* 74 * Interface driver methods. 75 */ 76 static void edsc_init(void *dummy); 77 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */ 78 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data); 79 static void edsc_start(struct ifnet *ifp); 80 81 /* 82 * We'll allocate softc instances from this. 83 */ 84 static MALLOC_DEFINE(M_EDSC, "edsc", "Ethernet discard interface"); 85 86 /* 87 * Attach to the interface cloning framework under the name of "edsc". 88 * The second argument is the number of units to be created from 89 * the outset. It's also the minimum number of units allowed. 90 * We don't want any units created as soon as the driver is loaded. 91 */ 92 IFC_SIMPLE_DECLARE(edsc, 0); 93 94 /* 95 * Create an interface instance. 96 */ 97 static int 98 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 99 { 100 struct edsc_softc *sc; 101 struct ifnet *ifp; 102 static u_char eaddr[ETHER_ADDR_LEN]; /* 0:0:0:0:0:0 */ 103 104 /* 105 * Allocate soft and ifnet structures. Link each to the other. 106 */ 107 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO); 108 ifp = sc->sc_ifp = if_alloc(IFT_ETHER); 109 if (ifp == NULL) { 110 free(sc, M_EDSC); 111 return (ENOSPC); 112 } 113 114 ifp->if_softc = sc; 115 116 /* 117 * Get a name for this particular interface in its ifnet structure. 118 */ 119 if_initname(ifp, ifc->ifc_name, unit); 120 121 /* 122 * Typical Ethernet interface flags: we can do broadcast and 123 * multicast but can't hear our own broadcasts or multicasts. 124 */ 125 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX; 126 127 /* 128 * We can pretent we have the whole set of hardware features 129 * because we just discard all packets we get from the upper layer. 130 * However, the features are disabled initially. They can be 131 * enabled via edsc_ioctl() when needed. 132 */ 133 ifp->if_capabilities = 134 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM | 135 IFCAP_HWCSUM | IFCAP_TSO | 136 IFCAP_JUMBO_MTU; 137 ifp->if_capenable = 0; 138 139 /* 140 * Set the interface driver methods. 141 */ 142 ifp->if_init = edsc_init; 143 /* ifp->if_input = edsc_input; */ 144 ifp->if_ioctl = edsc_ioctl; 145 ifp->if_start = edsc_start; 146 147 /* 148 * Set the maximum output queue length from the global parameter. 149 */ 150 ifp->if_snd.ifq_maxlen = ifqmaxlen; 151 152 /* 153 * Do ifnet initializations common to all Ethernet drivers 154 * and attach to the network interface framework. 155 * TODO: Pick a non-zero link level address. 156 */ 157 ether_ifattach(ifp, eaddr); 158 159 /* 160 * Now we can mark the interface as running, i.e., ready 161 * for operation. 162 */ 163 ifp->if_drv_flags |= IFF_DRV_RUNNING; 164 165 return (0); 166 } 167 168 /* 169 * Destroy an interface instance. 170 */ 171 static void 172 edsc_clone_destroy(struct ifnet *ifp) 173 { 174 struct edsc_softc *sc = ifp->if_softc; 175 176 /* 177 * Detach from the network interface framework. 178 */ 179 ether_ifdetach(ifp); 180 181 /* 182 * Free memory occupied by ifnet and softc. 183 */ 184 if_free(ifp); 185 free(sc, M_EDSC); 186 } 187 188 /* 189 * This method is invoked from ether_ioctl() when it's time 190 * to bring up the hardware. 191 */ 192 static void 193 edsc_init(void *dummy) 194 { 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; 198 199 /* blah-blah-blah */ 200 #endif 201 } 202 203 /* 204 * Network interfaces are controlled via the ioctl(2) syscall. 205 */ 206 static int 207 edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 208 { 209 struct ifreq *ifr = (struct ifreq *)data; 210 211 switch (cmd) { 212 case SIOCSIFCAP: 213 #if 1 214 /* 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. 218 */ 219 ifp->if_capenable = ifr->ifr_reqcap; 220 #else 221 /* 222 * A h/w driver would need to analyze the requested 223 * bits and program the hardware, e.g.: 224 */ 225 mask = ifp->if_capenable ^ ifr->ifr_reqcap; 226 227 if (mask & IFCAP_VLAN_HWTAGGING) { 228 ifp->if_capenable ^= IFCAP_VLAN_HWTAGGING; 229 230 if (ifp->if_capenable & IFCAP_VLAN_HWTAGGING) 231 /* blah-blah-blah */ 232 else 233 /* etc-etc-etc */ 234 } 235 #endif 236 break; 237 238 default: 239 /* 240 * Offload the rest onto the common Ethernet handler. 241 */ 242 return (ether_ioctl(ifp, cmd, data)); 243 } 244 245 return (0); 246 } 247 248 /* 249 * Process the output queue. 250 */ 251 static void 252 edsc_start(struct ifnet *ifp) 253 { 254 struct mbuf *m; 255 256 /* 257 * A hardware interface driver can set IFF_DRV_OACTIVE 258 * in ifp->if_drv_flags: 259 * 260 * ifp->if_drv_flags |= IFF_DRV_OACTIVE; 261 * 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. 268 * 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. 274 */ 275 276 /* 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. 281 */ 282 for (;;) { 283 /* 284 * Try to dequeue one packet. Stop if the queue is empty. 285 * Use IF_DEQUEUE() here if ALTQ(9) support is unneeded. 286 */ 287 IFQ_DEQUEUE(&ifp->if_snd, m); 288 if (m == NULL) 289 break; 290 291 /* 292 * Let bpf(9) at the packet. 293 */ 294 BPF_MTAP(ifp, m); 295 296 /* 297 * Update the interface counters. 298 */ 299 ifp->if_obytes += m->m_pkthdr.len; 300 ifp->if_opackets++; 301 302 /* 303 * Finally, just drop the packet. 304 * TODO: Reply to ARP requests unless IFF_NOARP is set. 305 */ 306 m_freem(m); 307 } 308 309 /* 310 * ifp->if_drv_flags &= ~IFF_DRV_OACTIVE; 311 * would be here only if the transmission were synchronous. 312 */ 313 } 314 315 /* 316 * This function provides handlers for module events, namely load and unload. 317 */ 318 static int 319 edsc_modevent(module_t mod, int type, void *data) 320 { 321 322 switch (type) { 323 case MOD_LOAD: 324 /* 325 * Connect to the network interface cloning framework. 326 */ 327 if_clone_attach(&edsc_cloner); 328 break; 329 330 case MOD_UNLOAD: 331 /* 332 * Disconnect from the cloning framework. 333 * Existing interfaces will be disposed of properly. 334 */ 335 if_clone_detach(&edsc_cloner); 336 break; 337 338 default: 339 /* 340 * There are other event types, but we don't handle them. 341 * See module(9). 342 */ 343 return (EOPNOTSUPP); 344 } 345 return (0); 346 } 347 348 static moduledata_t edsc_mod = { 349 "if_edsc", /* name */ 350 edsc_modevent, /* event handler */ 351 NULL /* additional data */ 352 }; 353 354 DECLARE_MODULE(if_edsc, edsc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 355