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> 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) */ 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 static struct if_clone *edsc_cloner; 73 static int edsc_clone_create(struct if_clone *, int, caddr_t); 74 static void edsc_clone_destroy(struct ifnet *); 75 76 /* 77 * Interface driver methods. 78 */ 79 static void edsc_init(void *dummy); 80 /* static void edsc_input(struct ifnet *ifp, struct mbuf *m); would be here */ 81 static int edsc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data); 82 static void edsc_start(struct ifnet *ifp); 83 84 /* 85 * We'll allocate softc instances from this. 86 */ 87 static MALLOC_DEFINE(M_EDSC, edscname, "Ethernet discard interface"); 88 89 /* 90 * Create an interface instance. 91 */ 92 static int 93 edsc_clone_create(struct if_clone *ifc, int unit, caddr_t params) 94 { 95 struct edsc_softc *sc; 96 struct ifnet *ifp; 97 static u_char eaddr[ETHER_ADDR_LEN]; /* 0:0:0:0:0:0 */ 98 99 /* 100 * Allocate soft and ifnet structures. Link each to the other. 101 */ 102 sc = malloc(sizeof(struct edsc_softc), M_EDSC, M_WAITOK | M_ZERO); 103 ifp = sc->sc_ifp = if_alloc(IFT_ETHER); 104 if (ifp == NULL) { 105 free(sc, M_EDSC); 106 return (ENOSPC); 107 } 108 109 ifp->if_softc = sc; 110 111 /* 112 * Get a name for this particular interface in its ifnet structure. 113 */ 114 if_initname(ifp, edscname, unit); 115 116 /* 117 * Typical Ethernet interface flags: we can do broadcast and 118 * multicast but can't hear our own broadcasts or multicasts. 119 */ 120 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST | IFF_SIMPLEX; 121 122 /* 123 * We can pretent we have the whole set of hardware features 124 * because we just discard all packets we get from the upper layer. 125 * However, the features are disabled initially. They can be 126 * enabled via edsc_ioctl() when needed. 127 */ 128 ifp->if_capabilities = 129 IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | IFCAP_VLAN_HWCSUM | 130 IFCAP_HWCSUM | IFCAP_TSO | 131 IFCAP_JUMBO_MTU; 132 ifp->if_capenable = 0; 133 134 /* 135 * Set the interface driver methods. 136 */ 137 ifp->if_init = edsc_init; 138 /* ifp->if_input = edsc_input; */ 139 ifp->if_ioctl = edsc_ioctl; 140 ifp->if_start = edsc_start; 141 142 /* 143 * Set the maximum output queue length from the global parameter. 144 */ 145 ifp->if_snd.ifq_maxlen = ifqmaxlen; 146 147 /* 148 * Do ifnet initializations common to all Ethernet drivers 149 * and attach to the network interface framework. 150 * TODO: Pick a non-zero link level address. 151 */ 152 ether_ifattach(ifp, eaddr); 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 ifp->if_obytes += m->m_pkthdr.len; 295 ifp->if_opackets++; 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 /* 311 * This function provides handlers for module events, namely load and unload. 312 */ 313 static int 314 edsc_modevent(module_t mod, int type, void *data) 315 { 316 317 switch (type) { 318 case MOD_LOAD: 319 /* 320 * Connect to the network interface cloning framework. 321 * The last argument is the number of units to be created 322 * from the outset. It's also the minimum number of units 323 * allowed. We don't want any units created as soon as the 324 * driver is loaded. 325 */ 326 edsc_cloner = if_clone_simple(edscname, edsc_clone_create, 327 edsc_clone_destroy, 0); 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