1 /* 2 * CAIF Interface registration. 3 * Copyright (C) ST-Ericsson AB 2010 4 * Author: Sjur Brendeland/sjur.brandeland@stericsson.com 5 * License terms: GNU General Public License (GPL) version 2 6 * 7 * Borrowed heavily from file: pn_dev.c. Thanks to 8 * Remi Denis-Courmont <remi.denis-courmont@nokia.com> 9 * and Sakari Ailus <sakari.ailus@nokia.com> 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ 13 14 #include <linux/kernel.h> 15 #include <linux/if_arp.h> 16 #include <linux/net.h> 17 #include <linux/netdevice.h> 18 #include <linux/mutex.h> 19 #include <linux/module.h> 20 #include <linux/spinlock.h> 21 #include <net/netns/generic.h> 22 #include <net/net_namespace.h> 23 #include <net/pkt_sched.h> 24 #include <net/caif/caif_device.h> 25 #include <net/caif/caif_layer.h> 26 #include <net/caif/cfpkt.h> 27 #include <net/caif/cfcnfg.h> 28 #include <net/caif/cfserl.h> 29 30 MODULE_LICENSE("GPL"); 31 32 /* Used for local tracking of the CAIF net devices */ 33 struct caif_device_entry { 34 struct cflayer layer; 35 struct list_head list; 36 struct net_device *netdev; 37 int __percpu *pcpu_refcnt; 38 spinlock_t flow_lock; 39 struct sk_buff *xoff_skb; 40 void (*xoff_skb_dtor)(struct sk_buff *skb); 41 bool xoff; 42 }; 43 44 struct caif_device_entry_list { 45 struct list_head list; 46 /* Protects simulanous deletes in list */ 47 struct mutex lock; 48 }; 49 50 struct caif_net { 51 struct cfcnfg *cfg; 52 struct caif_device_entry_list caifdevs; 53 }; 54 55 static int caif_net_id; 56 static int q_high = 50; /* Percent */ 57 58 struct cfcnfg *get_cfcnfg(struct net *net) 59 { 60 struct caif_net *caifn; 61 caifn = net_generic(net, caif_net_id); 62 if (!caifn) 63 return NULL; 64 return caifn->cfg; 65 } 66 EXPORT_SYMBOL(get_cfcnfg); 67 68 static struct caif_device_entry_list *caif_device_list(struct net *net) 69 { 70 struct caif_net *caifn; 71 caifn = net_generic(net, caif_net_id); 72 if (!caifn) 73 return NULL; 74 return &caifn->caifdevs; 75 } 76 77 static void caifd_put(struct caif_device_entry *e) 78 { 79 this_cpu_dec(*e->pcpu_refcnt); 80 } 81 82 static void caifd_hold(struct caif_device_entry *e) 83 { 84 this_cpu_inc(*e->pcpu_refcnt); 85 } 86 87 static int caifd_refcnt_read(struct caif_device_entry *e) 88 { 89 int i, refcnt = 0; 90 for_each_possible_cpu(i) 91 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i); 92 return refcnt; 93 } 94 95 /* Allocate new CAIF device. */ 96 static struct caif_device_entry *caif_device_alloc(struct net_device *dev) 97 { 98 struct caif_device_entry_list *caifdevs; 99 struct caif_device_entry *caifd; 100 101 caifdevs = caif_device_list(dev_net(dev)); 102 if (!caifdevs) 103 return NULL; 104 105 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL); 106 if (!caifd) 107 return NULL; 108 caifd->pcpu_refcnt = alloc_percpu(int); 109 if (!caifd->pcpu_refcnt) { 110 kfree(caifd); 111 return NULL; 112 } 113 caifd->netdev = dev; 114 dev_hold(dev); 115 return caifd; 116 } 117 118 static struct caif_device_entry *caif_get(struct net_device *dev) 119 { 120 struct caif_device_entry_list *caifdevs = 121 caif_device_list(dev_net(dev)); 122 struct caif_device_entry *caifd; 123 if (!caifdevs) 124 return NULL; 125 126 list_for_each_entry_rcu(caifd, &caifdevs->list, list) { 127 if (caifd->netdev == dev) 128 return caifd; 129 } 130 return NULL; 131 } 132 133 void caif_flow_cb(struct sk_buff *skb) 134 { 135 struct caif_device_entry *caifd; 136 void (*dtor)(struct sk_buff *skb) = NULL; 137 bool send_xoff; 138 139 WARN_ON(skb->dev == NULL); 140 141 rcu_read_lock(); 142 caifd = caif_get(skb->dev); 143 caifd_hold(caifd); 144 rcu_read_unlock(); 145 146 spin_lock_bh(&caifd->flow_lock); 147 send_xoff = caifd->xoff; 148 caifd->xoff = 0; 149 dtor = caifd->xoff_skb_dtor; 150 151 if (WARN_ON(caifd->xoff_skb != skb)) 152 skb = NULL; 153 154 caifd->xoff_skb = NULL; 155 caifd->xoff_skb_dtor = NULL; 156 157 spin_unlock_bh(&caifd->flow_lock); 158 159 if (dtor && skb) 160 dtor(skb); 161 162 if (send_xoff) 163 caifd->layer.up-> 164 ctrlcmd(caifd->layer.up, 165 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND, 166 caifd->layer.id); 167 caifd_put(caifd); 168 } 169 170 static int transmit(struct cflayer *layer, struct cfpkt *pkt) 171 { 172 int err, high = 0, qlen = 0; 173 struct caif_dev_common *caifdev; 174 struct caif_device_entry *caifd = 175 container_of(layer, struct caif_device_entry, layer); 176 struct sk_buff *skb; 177 struct netdev_queue *txq; 178 179 rcu_read_lock_bh(); 180 181 skb = cfpkt_tonative(pkt); 182 skb->dev = caifd->netdev; 183 skb_reset_network_header(skb); 184 skb->protocol = htons(ETH_P_CAIF); 185 caifdev = netdev_priv(caifd->netdev); 186 187 /* Check if we need to handle xoff */ 188 if (likely(caifd->netdev->tx_queue_len == 0)) 189 goto noxoff; 190 191 if (unlikely(caifd->xoff)) 192 goto noxoff; 193 194 if (likely(!netif_queue_stopped(caifd->netdev))) { 195 /* If we run with a TX queue, check if the queue is too long*/ 196 txq = netdev_get_tx_queue(skb->dev, 0); 197 qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc)); 198 199 if (likely(qlen == 0)) 200 goto noxoff; 201 202 high = (caifd->netdev->tx_queue_len * q_high) / 100; 203 if (likely(qlen < high)) 204 goto noxoff; 205 } 206 207 /* Hold lock while accessing xoff */ 208 spin_lock_bh(&caifd->flow_lock); 209 if (caifd->xoff) { 210 spin_unlock_bh(&caifd->flow_lock); 211 goto noxoff; 212 } 213 214 /* 215 * Handle flow off, we do this by temporary hi-jacking this 216 * skb's destructor function, and replace it with our own 217 * flow-on callback. The callback will set flow-on and call 218 * the original destructor. 219 */ 220 221 pr_debug("queue has stopped(%d) or is full (%d > %d)\n", 222 netif_queue_stopped(caifd->netdev), 223 qlen, high); 224 caifd->xoff = 1; 225 caifd->xoff_skb = skb; 226 caifd->xoff_skb_dtor = skb->destructor; 227 skb->destructor = caif_flow_cb; 228 spin_unlock_bh(&caifd->flow_lock); 229 230 caifd->layer.up->ctrlcmd(caifd->layer.up, 231 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, 232 caifd->layer.id); 233 noxoff: 234 rcu_read_unlock_bh(); 235 236 err = dev_queue_xmit(skb); 237 if (err > 0) 238 err = -EIO; 239 240 return err; 241 } 242 243 /* 244 * Stuff received packets into the CAIF stack. 245 * On error, returns non-zero and releases the skb. 246 */ 247 static int receive(struct sk_buff *skb, struct net_device *dev, 248 struct packet_type *pkttype, struct net_device *orig_dev) 249 { 250 struct cfpkt *pkt; 251 struct caif_device_entry *caifd; 252 int err; 253 254 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb); 255 256 rcu_read_lock(); 257 caifd = caif_get(dev); 258 259 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive || 260 !netif_oper_up(caifd->netdev)) { 261 rcu_read_unlock(); 262 kfree_skb(skb); 263 return NET_RX_DROP; 264 } 265 266 /* Hold reference to netdevice while using CAIF stack */ 267 caifd_hold(caifd); 268 rcu_read_unlock(); 269 270 err = caifd->layer.up->receive(caifd->layer.up, pkt); 271 272 /* For -EILSEQ the packet is not freed so so it now */ 273 if (err == -EILSEQ) 274 cfpkt_destroy(pkt); 275 276 /* Release reference to stack upwards */ 277 caifd_put(caifd); 278 279 if (err != 0) 280 err = NET_RX_DROP; 281 return err; 282 } 283 284 static struct packet_type caif_packet_type __read_mostly = { 285 .type = cpu_to_be16(ETH_P_CAIF), 286 .func = receive, 287 }; 288 289 static void dev_flowctrl(struct net_device *dev, int on) 290 { 291 struct caif_device_entry *caifd; 292 293 rcu_read_lock(); 294 295 caifd = caif_get(dev); 296 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { 297 rcu_read_unlock(); 298 return; 299 } 300 301 caifd_hold(caifd); 302 rcu_read_unlock(); 303 304 caifd->layer.up->ctrlcmd(caifd->layer.up, 305 on ? 306 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND : 307 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, 308 caifd->layer.id); 309 caifd_put(caifd); 310 } 311 312 void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev, 313 struct cflayer *link_support, int head_room, 314 struct cflayer **layer, int (**rcv_func)( 315 struct sk_buff *, struct net_device *, 316 struct packet_type *, struct net_device *)) 317 { 318 struct caif_device_entry *caifd; 319 enum cfcnfg_phy_preference pref; 320 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev)); 321 struct caif_device_entry_list *caifdevs; 322 323 caifdevs = caif_device_list(dev_net(dev)); 324 if (!cfg || !caifdevs) 325 return; 326 caifd = caif_device_alloc(dev); 327 if (!caifd) 328 return; 329 *layer = &caifd->layer; 330 spin_lock_init(&caifd->flow_lock); 331 332 switch (caifdev->link_select) { 333 case CAIF_LINK_HIGH_BANDW: 334 pref = CFPHYPREF_HIGH_BW; 335 break; 336 case CAIF_LINK_LOW_LATENCY: 337 pref = CFPHYPREF_LOW_LAT; 338 break; 339 default: 340 pref = CFPHYPREF_HIGH_BW; 341 break; 342 } 343 mutex_lock(&caifdevs->lock); 344 list_add_rcu(&caifd->list, &caifdevs->list); 345 346 strncpy(caifd->layer.name, dev->name, 347 sizeof(caifd->layer.name) - 1); 348 caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0; 349 caifd->layer.transmit = transmit; 350 cfcnfg_add_phy_layer(cfg, 351 dev, 352 &caifd->layer, 353 pref, 354 link_support, 355 caifdev->use_fcs, 356 head_room); 357 mutex_unlock(&caifdevs->lock); 358 if (rcv_func) 359 *rcv_func = receive; 360 } 361 EXPORT_SYMBOL(caif_enroll_dev); 362 363 /* notify Caif of device events */ 364 static int caif_device_notify(struct notifier_block *me, unsigned long what, 365 void *arg) 366 { 367 struct net_device *dev = arg; 368 struct caif_device_entry *caifd = NULL; 369 struct caif_dev_common *caifdev; 370 struct cfcnfg *cfg; 371 struct cflayer *layer, *link_support; 372 int head_room = 0; 373 struct caif_device_entry_list *caifdevs; 374 375 cfg = get_cfcnfg(dev_net(dev)); 376 caifdevs = caif_device_list(dev_net(dev)); 377 if (!cfg || !caifdevs) 378 return 0; 379 380 caifd = caif_get(dev); 381 if (caifd == NULL && dev->type != ARPHRD_CAIF) 382 return 0; 383 384 switch (what) { 385 case NETDEV_REGISTER: 386 if (caifd != NULL) 387 break; 388 389 caifdev = netdev_priv(dev); 390 391 link_support = NULL; 392 if (caifdev->use_frag) { 393 head_room = 1; 394 link_support = cfserl_create(dev->ifindex, 395 caifdev->use_stx); 396 if (!link_support) { 397 pr_warn("Out of memory\n"); 398 break; 399 } 400 } 401 caif_enroll_dev(dev, caifdev, link_support, head_room, 402 &layer, NULL); 403 caifdev->flowctrl = dev_flowctrl; 404 break; 405 406 case NETDEV_UP: 407 rcu_read_lock(); 408 409 caifd = caif_get(dev); 410 if (caifd == NULL) { 411 rcu_read_unlock(); 412 break; 413 } 414 415 caifd->xoff = 0; 416 cfcnfg_set_phy_state(cfg, &caifd->layer, true); 417 rcu_read_unlock(); 418 419 break; 420 421 case NETDEV_DOWN: 422 rcu_read_lock(); 423 424 caifd = caif_get(dev); 425 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { 426 rcu_read_unlock(); 427 return -EINVAL; 428 } 429 430 cfcnfg_set_phy_state(cfg, &caifd->layer, false); 431 caifd_hold(caifd); 432 rcu_read_unlock(); 433 434 caifd->layer.up->ctrlcmd(caifd->layer.up, 435 _CAIF_CTRLCMD_PHYIF_DOWN_IND, 436 caifd->layer.id); 437 438 spin_lock_bh(&caifd->flow_lock); 439 440 /* 441 * Replace our xoff-destructor with original destructor. 442 * We trust that skb->destructor *always* is called before 443 * the skb reference is invalid. The hijacked SKB destructor 444 * takes the flow_lock so manipulating the skb->destructor here 445 * should be safe. 446 */ 447 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL) 448 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor; 449 450 caifd->xoff = 0; 451 caifd->xoff_skb_dtor = NULL; 452 caifd->xoff_skb = NULL; 453 454 spin_unlock_bh(&caifd->flow_lock); 455 caifd_put(caifd); 456 break; 457 458 case NETDEV_UNREGISTER: 459 mutex_lock(&caifdevs->lock); 460 461 caifd = caif_get(dev); 462 if (caifd == NULL) { 463 mutex_unlock(&caifdevs->lock); 464 break; 465 } 466 list_del_rcu(&caifd->list); 467 468 /* 469 * NETDEV_UNREGISTER is called repeatedly until all reference 470 * counts for the net-device are released. If references to 471 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for 472 * the next call to NETDEV_UNREGISTER. 473 * 474 * If any packets are in flight down the CAIF Stack, 475 * cfcnfg_del_phy_layer will return nonzero. 476 * If no packets are in flight, the CAIF Stack associated 477 * with the net-device un-registering is freed. 478 */ 479 480 if (caifd_refcnt_read(caifd) != 0 || 481 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) { 482 483 pr_info("Wait for device inuse\n"); 484 /* Enrole device if CAIF Stack is still in use */ 485 list_add_rcu(&caifd->list, &caifdevs->list); 486 mutex_unlock(&caifdevs->lock); 487 break; 488 } 489 490 synchronize_rcu(); 491 dev_put(caifd->netdev); 492 free_percpu(caifd->pcpu_refcnt); 493 kfree(caifd); 494 495 mutex_unlock(&caifdevs->lock); 496 break; 497 } 498 return 0; 499 } 500 501 static struct notifier_block caif_device_notifier = { 502 .notifier_call = caif_device_notify, 503 .priority = 0, 504 }; 505 506 /* Per-namespace Caif devices handling */ 507 static int caif_init_net(struct net *net) 508 { 509 struct caif_net *caifn = net_generic(net, caif_net_id); 510 if (WARN_ON(!caifn)) 511 return -EINVAL; 512 513 INIT_LIST_HEAD(&caifn->caifdevs.list); 514 mutex_init(&caifn->caifdevs.lock); 515 516 caifn->cfg = cfcnfg_create(); 517 if (!caifn->cfg) 518 return -ENOMEM; 519 520 return 0; 521 } 522 523 static void caif_exit_net(struct net *net) 524 { 525 struct caif_device_entry *caifd, *tmp; 526 struct caif_device_entry_list *caifdevs = 527 caif_device_list(net); 528 struct cfcnfg *cfg = get_cfcnfg(net); 529 530 if (!cfg || !caifdevs) 531 return; 532 533 rtnl_lock(); 534 mutex_lock(&caifdevs->lock); 535 536 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) { 537 int i = 0; 538 list_del_rcu(&caifd->list); 539 cfcnfg_set_phy_state(cfg, &caifd->layer, false); 540 541 while (i < 10 && 542 (caifd_refcnt_read(caifd) != 0 || 543 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) { 544 545 pr_info("Wait for device inuse\n"); 546 msleep(250); 547 i++; 548 } 549 synchronize_rcu(); 550 dev_put(caifd->netdev); 551 free_percpu(caifd->pcpu_refcnt); 552 kfree(caifd); 553 } 554 cfcnfg_remove(cfg); 555 556 mutex_unlock(&caifdevs->lock); 557 rtnl_unlock(); 558 } 559 560 static struct pernet_operations caif_net_ops = { 561 .init = caif_init_net, 562 .exit = caif_exit_net, 563 .id = &caif_net_id, 564 .size = sizeof(struct caif_net), 565 }; 566 567 /* Initialize Caif devices list */ 568 static int __init caif_device_init(void) 569 { 570 int result; 571 572 result = register_pernet_device(&caif_net_ops); 573 574 if (result) 575 return result; 576 577 register_netdevice_notifier(&caif_device_notifier); 578 dev_add_pack(&caif_packet_type); 579 580 return result; 581 } 582 583 static void __exit caif_device_exit(void) 584 { 585 unregister_pernet_device(&caif_net_ops); 586 unregister_netdevice_notifier(&caif_device_notifier); 587 dev_remove_pack(&caif_packet_type); 588 } 589 590 module_init(caif_device_init); 591 module_exit(caif_device_exit); 592