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