/* * net/tipc/net.c: TIPC network routing code * * Copyright (c) 1995-2006, Ericsson AB * Copyright (c) 2005, Wind River Systems * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the names of the copyright holders nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * Alternatively, this software may be distributed under the terms of the * GNU General Public License ("GPL") version 2 as published by the Free * Software Foundation. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "core.h" #include "bearer.h" #include "net.h" #include "zone.h" #include "addr.h" #include "name_table.h" #include "name_distr.h" #include "subscr.h" #include "link.h" #include "msg.h" #include "port.h" #include "bcast.h" #include "discover.h" #include "config.h" /* * The TIPC locking policy is designed to ensure a very fine locking * granularity, permitting complete parallel access to individual * port and node/link instances. The code consists of three major * locking domains, each protected with their own disjunct set of locks. * * 1: The routing hierarchy. * Comprises the structures 'zone', 'cluster', 'node', 'link' * and 'bearer'. The whole hierarchy is protected by a big * read/write lock, tipc_net_lock, to enssure that nothing is added * or removed while code is accessing any of these structures. * This layer must not be called from the two others while they * hold any of their own locks. * Neither must it itself do any upcalls to the other two before * it has released tipc_net_lock and other protective locks. * * Within the tipc_net_lock domain there are two sub-domains;'node' and * 'bearer', where local write operations are permitted, * provided that those are protected by individual spin_locks * per instance. Code holding tipc_net_lock(read) and a node spin_lock * is permitted to poke around in both the node itself and its * subordinate links. I.e, it can update link counters and queues, * change link state, send protocol messages, and alter the * "active_links" array in the node; but it can _not_ remove a link * or a node from the overall structure. * Correspondingly, individual bearers may change status within a * tipc_net_lock(read), protected by an individual spin_lock ber bearer * instance, but it needs tipc_net_lock(write) to remove/add any bearers. * * * 2: The transport level of the protocol. * This consists of the structures port, (and its user level * representations, such as user_port and tipc_sock), reference and * tipc_user (port.c, reg.c, socket.c). * * This layer has four different locks: * - The tipc_port spin_lock. This is protecting each port instance * from parallel data access and removal. Since we can not place * this lock in the port itself, it has been placed in the * corresponding reference table entry, which has the same life * cycle as the module. This entry is difficult to access from * outside the TIPC core, however, so a pointer to the lock has * been added in the port instance, -to be used for unlocking * only. * - A read/write lock to protect the reference table itself (teg.c). * (Nobody is using read-only access to this, so it can just as * well be changed to a spin_lock) * - A spin lock to protect the registry of kernel/driver users (reg.c) * - A global spin_lock (tipc_port_lock), which only task is to ensure * consistency where more than one port is involved in an operation, * i.e., whe a port is part of a linked list of ports. * There are two such lists; 'port_list', which is used for management, * and 'wait_list', which is used to queue ports during congestion. * * 3: The name table (name_table.c, name_distr.c, subscription.c) * - There is one big read/write-lock (tipc_nametbl_lock) protecting the * overall name table structure. Nothing must be added/removed to * this structure without holding write access to it. * - There is one local spin_lock per sub_sequence, which can be seen * as a sub-domain to the tipc_nametbl_lock domain. It is used only * for translation operations, and is needed because a translation * steps the root of the 'publication' linked list between each lookup. * This is always used within the scope of a tipc_nametbl_lock(read). * - A local spin_lock protecting the queue of subscriber events. */ DEFINE_RWLOCK(tipc_net_lock); struct network tipc_net = { NULL }; struct tipc_node *tipc_net_select_remote_node(u32 addr, u32 ref) { return tipc_zone_select_remote_node(tipc_net.zones[tipc_zone(addr)], addr, ref); } u32 tipc_net_select_router(u32 addr, u32 ref) { return tipc_zone_select_router(tipc_net.zones[tipc_zone(addr)], addr, ref); } #if 0 u32 tipc_net_next_node(u32 a) { if (tipc_net.zones[tipc_zone(a)]) return tipc_zone_next_node(a); return 0; } #endif void tipc_net_remove_as_router(u32 router) { u32 z_num; for (z_num = 1; z_num <= tipc_max_zones; z_num++) { if (!tipc_net.zones[z_num]) continue; tipc_zone_remove_as_router(tipc_net.zones[z_num], router); } } void tipc_net_send_external_routes(u32 dest) { u32 z_num; for (z_num = 1; z_num <= tipc_max_zones; z_num++) { if (tipc_net.zones[z_num]) tipc_zone_send_external_routes(tipc_net.zones[z_num], dest); } } static int net_init(void) { memset(&tipc_net, 0, sizeof(tipc_net)); tipc_net.zones = kcalloc(tipc_max_zones + 1, sizeof(struct _zone *), GFP_ATOMIC); if (!tipc_net.zones) { return -ENOMEM; } return 0; } static void net_stop(void) { u32 z_num; if (!tipc_net.zones) return; for (z_num = 1; z_num <= tipc_max_zones; z_num++) { tipc_zone_delete(tipc_net.zones[z_num]); } kfree(tipc_net.zones); tipc_net.zones = NULL; } static void net_route_named_msg(struct sk_buff *buf) { struct tipc_msg *msg = buf_msg(buf); u32 dnode; u32 dport; if (!msg_named(msg)) { msg_dbg(msg, "tipc_net->drop_nam:"); buf_discard(buf); return; } dnode = addr_domain(msg_lookup_scope(msg)); dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode); dbg("tipc_net->lookup<%u,%u>-><%u,%x>\n", msg_nametype(msg), msg_nameinst(msg), dport, dnode); if (dport) { msg_set_destnode(msg, dnode); msg_set_destport(msg, dport); tipc_net_route_msg(buf); return; } msg_dbg(msg, "tipc_net->rej:NO NAME: "); tipc_reject_msg(buf, TIPC_ERR_NO_NAME); } void tipc_net_route_msg(struct sk_buff *buf) { struct tipc_msg *msg; u32 dnode; if (!buf) return; msg = buf_msg(buf); msg_incr_reroute_cnt(msg); if (msg_reroute_cnt(msg) > 6) { if (msg_errcode(msg)) { msg_dbg(msg, "NET>DISC>:"); buf_discard(buf); } else { msg_dbg(msg, "NET>REJ>:"); tipc_reject_msg(buf, msg_destport(msg) ? TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME); } return; } msg_dbg(msg, "tipc_net->rout: "); /* Handle message for this node */ dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg); if (in_scope(dnode, tipc_own_addr)) { if (msg_isdata(msg)) { if (msg_mcast(msg)) tipc_port_recv_mcast(buf, NULL); else if (msg_destport(msg)) tipc_port_recv_msg(buf); else net_route_named_msg(buf); return; } switch (msg_user(msg)) { case ROUTE_DISTRIBUTOR: tipc_cltr_recv_routing_table(buf); break; case NAME_DISTRIBUTOR: tipc_named_recv(buf); break; case CONN_MANAGER: tipc_port_recv_proto_msg(buf); break; default: msg_dbg(msg,"DROP/NET/SEND>: "); tipc_link_send(buf, dnode, msg_link_selector(msg)); } int tipc_net_start(u32 addr) { char addr_string[16]; int res; if (tipc_mode != TIPC_NODE_MODE) return -ENOPROTOOPT; tipc_subscr_stop(); tipc_cfg_stop(); tipc_own_addr = addr; tipc_mode = TIPC_NET_MODE; tipc_named_reinit(); tipc_port_reinit(); if ((res = tipc_bearer_init()) || (res = net_init()) || (res = tipc_cltr_init()) || (res = tipc_bclink_init())) { return res; } tipc_k_signal((Handler)tipc_subscr_start, 0); tipc_k_signal((Handler)tipc_cfg_init, 0); info("Started in network mode\n"); info("Own node address %s, network identity %u\n", addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); return 0; } void tipc_net_stop(void) { if (tipc_mode != TIPC_NET_MODE) return; write_lock_bh(&tipc_net_lock); tipc_bearer_stop(); tipc_mode = TIPC_NODE_MODE; tipc_bclink_stop(); net_stop(); write_unlock_bh(&tipc_net_lock); info("Left network mode \n"); } ef='#n165'>165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 
/*
 * USB Network driver infrastructure
 * Copyright (C) 2000-2005 by David Brownell
 * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * This is a generic "USB networking" framework that works with several
 * kinds of full and high speed networking devices:  host-to-host cables,
 * smart usb peripherals, and actual Ethernet adapters.
 *
 * These devices usually differ in terms of control protocols (if they
 * even have one!) and sometimes they define new framing to wrap or batch
 * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
 * so interface (un)binding, endpoint I/O queues, fault handling, and other
 * issues can usefully be addressed by this framework.
 */

// #define	DEBUG			// error path messages, extra info
// #define	VERBOSE			// more; success messages

#include <linux/config.h>
#ifdef	CONFIG_USB_DEBUG
#   define DEBUG
#endif
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>

#include "usbnet.h"

#define DRIVER_VERSION		"22-Aug-2005"


/*-------------------------------------------------------------------------*/

/*
 * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
 * Several dozen bytes of IPv4 data can fit in two such transactions.
 * One maximum size Ethernet packet takes twenty four of them.
 * For high speed, each frame comfortably fits almost 36 max size
 * Ethernet packets (so queues should be bigger).
 *
 * REVISIT qlens should be members of 'struct usbnet'; the goal is to
 * let the USB host controller be busy for 5msec or more before an irq
 * is required, under load.  Jumbograms change the equation.
 */
#define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)
#define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 60 : 4)

// reawaken network queue this soon after stopping; else watchdog barks
#define TX_TIMEOUT_JIFFIES	(5*HZ)

// throttle rx/tx briefly after some faults, so khubd might disconnect()
// us (it polls at HZ/4 usually) before we report too many false errors.
#define THROTTLE_JIFFIES	(HZ/8)

// between wakeups
#define UNLINK_TIMEOUT_MS	3

/*-------------------------------------------------------------------------*/

// randomly generated ethernet address
static u8	node_id [ETH_ALEN];

static const char driver_name [] = "usbnet";

/* use ethtool to change the level for any given device */
static int msg_level = -1;
module_param (msg_level, int, 0);
MODULE_PARM_DESC (msg_level, "Override default message level");

/*-------------------------------------------------------------------------*/

/* handles CDC Ethernet and many other network "bulk data" interfaces */
int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
{
	int				tmp;
	struct usb_host_interface	*alt = NULL;
	struct usb_host_endpoint	*in = NULL, *out = NULL;
	struct usb_host_endpoint	*status = NULL;

	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
		unsigned	ep;

		in = out = status = NULL;
		alt = intf->altsetting + tmp;

		/* take the first altsetting with in-bulk + out-bulk;
		 * remember any status endpoint, just in case;
		 * ignore other endpoints and altsetttings.
		 */
		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
			struct usb_host_endpoint	*e;
			int				intr = 0;

			e = alt->endpoint + ep;
			switch (e->desc.bmAttributes) {
			case USB_ENDPOINT_XFER_INT:
				if (!(e->desc.bEndpointAddress & USB_DIR_IN))
					continue;
				intr = 1;
				/* FALLTHROUGH */
			case USB_ENDPOINT_XFER_BULK:
				break;
			default:
				continue;
			}
			if (e->desc.bEndpointAddress & USB_DIR_IN) {
				if (!intr && !in)
					in = e;
				else if (intr && !status)
					status = e;
			} else {
				if (!out)
					out = e;
			}
		}
		if (in && out)
			break;
	}
	if (!alt || !in || !out)
		return -EINVAL;

	if (alt->desc.bAlternateSetting != 0
			|| !(dev->driver_info->flags & FLAG_NO_SETINT)) {
		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
				alt->desc.bAlternateSetting);
		if (tmp < 0)
			return tmp;
	}
	
	dev->in = usb_rcvbulkpipe (dev->udev,
			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->out = usb_sndbulkpipe (dev->udev,
			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->status = status;
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_get_endpoints);

static void intr_complete (struct urb *urb, struct pt_regs *regs);

static int init_status (struct usbnet *dev, struct usb_interface *intf)
{
	char		*buf = NULL;
	unsigned	pipe = 0;
	unsigned	maxp;
	unsigned	period;

	if (!dev->driver_info->status)
		return 0;

	pipe = usb_rcvintpipe (dev->udev,
			dev->status->desc.bEndpointAddress
				& USB_ENDPOINT_NUMBER_MASK);
	maxp = usb_maxpacket (dev->udev, pipe, 0);

	/* avoid 1 msec chatter:  min 8 msec poll rate */
	period = max ((int) dev->status->desc.bInterval,
		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);

	buf = kmalloc (maxp, SLAB_KERNEL);
	if (buf) {
		dev->interrupt = usb_alloc_urb (0, SLAB_KERNEL);
		if (!dev->interrupt) {
			kfree (buf);
			return -ENOMEM;
		} else {
			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
				buf, maxp, intr_complete, dev, period);
			dev_dbg(&intf->dev,
				"status ep%din, %d bytes period %d\n",
				usb_pipeendpoint(pipe), maxp, period);
		}
	}
	return  0;
}

/* Passes this packet up the stack, updating its accounting.
 * Some link protocols batch packets, so their rx_fixup paths
 * can return clones as well as just modify the original skb.
 */
void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
{
	int	status;

	skb->dev = dev->net;
	skb->protocol = eth_type_trans (skb, dev->net);
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;

	if (netif_msg_rx_status (dev))
		devdbg (dev, "< rx, len %zu, type 0x%x",
			skb->len + sizeof (struct ethhdr), skb->protocol);
	memset (skb->cb, 0, sizeof (struct skb_data));
	status = netif_rx (skb);
	if (status != NET_RX_SUCCESS && netif_msg_rx_err (dev))
		devdbg (dev, "netif_rx status %d", status);
}
EXPORT_SYMBOL_GPL(usbnet_skb_return);


/*-------------------------------------------------------------------------
 *
 * Network Device Driver (peer link to "Host Device", from USB host)
 *
 *-------------------------------------------------------------------------*/

static int usbnet_change_mtu (struct net_device *net, int new_mtu)
{
	struct usbnet	*dev = netdev_priv(net);
	int		ll_mtu = new_mtu + net->hard_header_len;

	if (new_mtu <= 0 || ll_mtu > dev->hard_mtu)
		return -EINVAL;
	// no second zero-length packet read wanted after mtu-sized packets
	if ((ll_mtu % dev->maxpacket) == 0)
		return -EDOM;
	net->mtu = new_mtu;
	return 0;
}

/*-------------------------------------------------------------------------*/

static struct net_device_stats *usbnet_get_stats (struct net_device *net)
{
	struct usbnet	*dev = netdev_priv(net);
	return &dev->stats;
}

/*-------------------------------------------------------------------------*/

/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 * completion callbacks.  2.5 should have fixed those bugs...
 */

static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
{
	unsigned long		flags;

	spin_lock_irqsave(&list->lock, flags);
	__skb_unlink(skb, list);
	spin_unlock(&list->lock);
	spin_lock(&dev->done.lock);
	__skb_queue_tail(&dev->done, skb);
	if (dev->done.qlen == 1)
		tasklet_schedule(&dev->bh);
	spin_unlock_irqrestore(&dev->done.lock, flags);
}

/* some work can't be done in tasklets, so we use keventd
 *
 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 * but tasklet_schedule() doesn't.  hope the failure is rare.
 */
void usbnet_defer_kevent (struct usbnet *dev, int work)
{
	set_bit (work, &dev->flags);
	if (!schedule_work (&dev->kevent))
		deverr (dev, "kevent %d may have been dropped", work);
	else
		devdbg (dev, "kevent %d scheduled", work);
}
EXPORT_SYMBOL_GPL(usbnet_defer_kevent);

/*-------------------------------------------------------------------------*/

static void rx_complete (struct urb *urb, struct pt_regs *regs);

static void rx_submit (struct usbnet *dev, struct urb *urb, unsigned flags)
{
	struct sk_buff		*skb;
	struct skb_data		*entry;
	int			retval = 0;
	unsigned long		lockflags;
	size_t			size = dev->rx_urb_size;

	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
		if (netif_msg_rx_err (dev))
			devdbg (dev, "no rx skb");
		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
		usb_free_urb (urb);
		return;
	}
	skb_reserve (skb, NET_IP_ALIGN);

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;
	entry->state = rx_start;
	entry->length = 0;

	usb_fill_bulk_urb (urb, dev->udev, dev->in,
		skb->data, size, rx_complete, skb);

	spin_lock_irqsave (&dev->rxq.lock, lockflags);

	if (netif_running (dev->net)
			&& netif_device_present (dev->net)
			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)){ 
		case -EPIPE:
			usbnet_defer_kevent (dev, EVENT_RX_HALT);
			break;
		case -ENOMEM:
			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
			break;
		case -ENODEV:
			if (netif_msg_ifdown (dev))
				devdbg (dev, "device gone");
			netif_device_detach (dev->net);
			break;
		default:
			if (netif_msg_rx_err (dev))
				devdbg (dev, "rx submit, %d", retval);
			tasklet_schedule (&dev->bh);
			break;
		case 0:
			__skb_queue_tail (&dev->rxq, skb);
		}
	} else {
		if (netif_msg_ifdown (dev))
			devdbg (dev, "rx: stopped");
		retval = -ENOLINK;
	}
	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
	if (retval) {
		dev_kfree_skb_any (skb);
		usb_free_urb (urb);
	}
}


/*-------------------------------------------------------------------------*/

static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
{
	if (dev->driver_info->rx_fixup
			&& !dev->driver_info->rx_fixup (dev, skb))
		goto error;
	// else network stack removes extra byte if we forced a short packet

	if (skb->len)
		usbnet_skb_return (dev, skb);
	else {
		if (netif_msg_rx_err (dev))
			devdbg (dev, "drop");
error:
		dev->stats.rx_errors++;
		skb_queue_tail (&dev->done, skb);
	}
}

/*-------------------------------------------------------------------------*/

static void rx_complete (struct urb *urb, struct pt_regs *regs)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;
	int			urb_status = urb->status;

	skb_put (skb, urb->actual_length);
	entry->state = rx_done;
	entry->urb = NULL;

	switch (urb_status) {
	    // success
	    case 0:
		if (skb->len < dev->net->hard_header_len) {
			entry->state = rx_cleanup;
			dev->stats.rx_errors++;
			dev->stats.rx_length_errors++;
			if (netif_msg_rx_err (dev))
				devdbg (dev, "rx length %d", skb->len);
		}
		break;

	    // stalls need manual reset. this is rare ... except that
	    // when going through USB 2.0 TTs, unplug appears this way.
	    // we avoid the highspeed version of the ETIMEOUT/EILSEQ
	    // storm, recovering as needed.
	    case -EPIPE:
		dev->stats.rx_errors++;
		usbnet_defer_kevent (dev, EVENT_RX_HALT);
		// FALLTHROUGH

	    // software-driven interface shutdown
	    case -ECONNRESET:		// async unlink
	    case -ESHUTDOWN:		// hardware gone
		if (netif_msg_ifdown (dev))
			devdbg (dev, "rx shutdown, code %d", urb_status);
		goto block;

	    // we get controller i/o faults during khubd disconnect() delays.
	    // throttle down resubmits, to avoid log floods; just temporarily,
	    // so we still recover when the fault isn't a khubd delay.
	    case -EPROTO:		// ehci
	    case -ETIMEDOUT:		// ohci
	    case -EILSEQ:		// uhci
		dev->stats.rx_errors++;
		if (!timer_pending (&dev->delay)) {
			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
			if (netif_msg_link (dev))
				devdbg (dev, "rx throttle %d", urb_status);
		}
block:
		entry->state = rx_cleanup;
		entry->urb = urb;
		urb = NULL;
		break;

	    // data overrun ... flush fifo?
	    case -EOVERFLOW:
		dev->stats.rx_over_errors++;
		// FALLTHROUGH
	    
	    default:
		entry->state = rx_cleanup;
		dev->stats.rx_errors++;
		if (netif_msg_rx_err (dev))
			devdbg (dev, "rx status %d", urb_status);
		break;
	}

	defer_bh(dev, skb, &dev->rxq);

	if (urb) {
		if (netif_running (dev->net)
				&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
			rx_submit (dev, urb, GFP_ATOMIC);
			return;
		}
		usb_free_urb (urb);
	}
	if (netif_msg_rx_err (dev))
		devdbg (dev, "no read resubmitted");
}

static void intr_complete (struct urb *urb, struct pt_regs *regs)
{
	struct usbnet	*dev = urb->context;
	int		status = urb->status;

	switch (status) {
	    /* success */
	    case 0:
		dev->driver_info->status(dev, urb);
		break;

	    /* software-driven interface shutdown */
	    case -ENOENT:		// urb killed
	    case -ESHUTDOWN:		// hardware gone
		if (netif_msg_ifdown (dev))
			devdbg (dev, "intr shutdown, code %d", status);
		return;

	    /* NOTE:  not throttling like RX/TX, since this endpoint
	     * already polls infrequently
	     */
	    default:
		devdbg (dev, "intr status %d", status);
		break;
	}

	if (!netif_running (dev->net))
		return;

	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
	status = usb_submit_urb (urb, GFP_ATOMIC);
	if (status != 0 && netif_msg_timer (dev))
		deverr(dev, "intr resubmit --> %d", status);
}

/*-------------------------------------------------------------------------*/

// unlink pending rx/tx; completion handlers do all other cleanup

static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
{
	unsigned long		flags;
	struct sk_buff		*skb, *skbnext;
	int			count = 0;

	spin_lock_irqsave (&q->lock, flags);
	for (skb = q->next; skb != (struct sk_buff *) q; skb = skbnext) {
		struct skb_data		*entry;
		struct urb		*urb;
		int			retval;

		entry = (struct skb_data *) skb->cb;
		urb = entry->urb;
		skbnext = skb->next;

		// during some PM-driven resume scenarios,
		// these (async) unlinks complete immediately
		retval = usb_unlink_urb (urb);
		if (retval != -EINPROGRESS && retval != 0)
			devdbg (dev, "unlink urb err, %d", retval);
		else
			count++;
	}
	spin_unlock_irqrestore (&q->lock, flags);
	return count;
}


/*-------------------------------------------------------------------------*/

// precondition: never called in_interrupt

static int usbnet_stop (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			temp;
	DECLARE_WAIT_QUEUE_HEAD (unlink_wakeup); 
	DECLARE_WAITQUEUE (wait, current);

	netif_stop_queue (net);

	if (netif_msg_ifdown (dev))
		devinfo (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld",
			dev->stats.rx_packets, dev->stats.tx_packets, 
			dev->stats.rx_errors, dev->stats.tx_errors
			);

	// ensure there are no more active urbs
	add_wait_queue (&unlink_wakeup, &wait);
	dev->wait = &unlink_wakeup;
	temp = unlink_urbs (dev, &dev->txq) + unlink_urbs (dev, &dev->rxq);

	// maybe wait for deletions to finish.
	while (!skb_queue_empty(&dev->rxq) &&
	       !skb_queue_empty(&dev->txq) &&
	       !skb_queue_empty(&dev->done)) {
		msleep(UNLINK_TIMEOUT_MS);
		if (netif_msg_ifdown (dev))
			devdbg (dev, "waited for %d urb completions", temp);
	}
	dev->wait = NULL;
	remove_wait_queue (&unlink_wakeup, &wait); 

	usb_kill_urb(dev->interrupt);

	/* deferred work (task, timer, softirq) must also stop.
	 * can't flush_scheduled_work() until we drop rtnl (later),
	 * else workers could deadlock; so make workers a NOP.
	 */
	dev->flags = 0;
	del_timer_sync (&dev->delay);
	tasklet_kill (&dev->bh);

	return 0;
}

/*-------------------------------------------------------------------------*/

// posts reads, and enables write queuing

// precondition: never called in_interrupt

static int usbnet_open (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			retval = 0;
	struct driver_info	*info = dev->driver_info;

	// put into "known safe" state
	if (info->reset && (retval = info->reset (dev)) < 0) {
		if (netif_msg_ifup (dev))
			devinfo (dev,
				"open reset fail (%d) usbnet usb-%s-%s, %s",
				retval,
				dev->udev->bus->bus_name, dev->udev->devpath,
			info->description);
		goto done;
	}

	// insist peer be connected
	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
		if (netif_msg_ifup (dev))
			devdbg (dev, "can't open; %d", retval);
		goto done;
	}

	/* start any status interrupt transfer */
	if (dev->interrupt) {
		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
		if (retval < 0) {
			if (netif_msg_ifup (dev))
				deverr (dev, "intr submit %d", retval);
			goto done;
		}
	}

	netif_start_queue (net);
	if (netif_msg_ifup (dev)) {
		char	*framing;

		if (dev->driver_info->flags & FLAG_FRAMING_NC)
			framing = "NetChip";
		else if (dev->driver_info->flags & FLAG_FRAMING_GL)
			framing = "GeneSys";
		else if (dev->driver_info->flags & FLAG_FRAMING_Z)
			framing = "Zaurus";
		else if (dev->driver_info->flags & FLAG_FRAMING_RN)
			framing = "RNDIS";
		else if (dev->driver_info->flags & FLAG_FRAMING_AX)
			framing = "ASIX";
		else
			framing = "simple";

		devinfo (dev, "open: enable queueing "
				"(rx %d, tx %d) mtu %d %s framing",
			RX_QLEN (dev), TX_QLEN (dev), dev->net->mtu,
			framing);
	}

	// delay posting reads until we're fully open
	tasklet_schedule (&dev->bh);
done:
	return retval;
}

/*-------------------------------------------------------------------------*/

/* ethtool methods; minidrivers may need to add some more, but
 * they'll probably want to use this base set.
 */

void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
{
	struct usbnet *dev = netdev_priv(net);

	/* REVISIT don't always return "usbnet" */
	strncpy (info->driver, driver_name, sizeof info->driver);
	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
	strncpy (info->fw_version, dev->driver_info->description,
		sizeof info->fw_version);
	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
}
EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);

static u32 usbnet_get_link (struct net_device *net)
{
	struct usbnet *dev = netdev_priv(net);

	/* If a check_connect is defined, return its result */
	if (dev->driver_info->check_connect)
		return dev->driver_info->check_connect (dev) == 0;

	/* Otherwise, say we're up (to avoid breaking scripts) */
	return 1;
}

u32 usbnet_get_msglevel (struct net_device *net)
{
	struct usbnet *dev = netdev_priv(net);

	return dev->msg_enable;
}
EXPORT_SYMBOL_GPL(usbnet_get_msglevel);

void usbnet_set_msglevel (struct net_device *net, u32 level)
{
	struct usbnet *dev = netdev_priv(net);

	dev->msg_enable = level;
}
EXPORT_SYMBOL_GPL(usbnet_set_msglevel);

/* drivers may override default ethtool_ops in their bind() routine */
static struct ethtool_ops usbnet_ethtool_ops = {
	.get_drvinfo		= usbnet_get_drvinfo,
	.get_link		= usbnet_get_link,
	.get_msglevel		= usbnet_get_msglevel,
	.set_msglevel		= usbnet_set_msglevel,
};

/*-------------------------------------------------------------------------*/

/* work that cannot be done in interrupt context uses keventd.
 *
 * NOTE:  with 2.5 we could do more of this using completion callbacks,
 * especially now that control transfers can be queued.
 */
static void
kevent (void *data)
{
	struct usbnet		*dev = data;
	int			status;

	/* usb_clear_halt() needs a thread context */
	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
		unlink_urbs (dev, &dev->txq);
		status = usb_clear_halt (dev->udev, dev->out);
		if (status < 0
				&& status != -EPIPE
				&& status != -ESHUTDOWN) {
			if (netif_msg_tx_err (dev))
				deverr (dev, "can't clear tx halt, status %d",
					status);
		} else {
			clear_bit (EVENT_TX_HALT, &dev->flags);
			if (status != -ESHUTDOWN)
				netif_wake_queue (dev->net);
		}
	}
	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
		unlink_urbs (dev, &dev->rxq);
		status = usb_clear_halt (dev->udev, dev->in);
		if (status < 0
				&& status != -EPIPE
				&& status != -ESHUTDOWN) {
			if (netif_msg_rx_err (dev))
				deverr (dev, "can't clear rx halt, status %d",
					status);
		} else {
			clear_bit (EVENT_RX_HALT, &dev->flags);
			tasklet_schedule (&dev->bh);
		}
	}

	/* tasklet could resubmit itself forever if memory is tight */
	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
		struct urb	*urb = NULL;

		if (netif_running (dev->net))
			urb = usb_alloc_urb (0, GFP_KERNEL);
		else
			clear_bit (EVENT_RX_MEMORY, &dev->flags);
		if (urb != NULL) {
			clear_bit (EVENT_RX_MEMORY, &dev->flags);
			rx_submit (dev, urb, GFP_KERNEL);
			tasklet_schedule (&dev->bh);
		}
	}

	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
		struct driver_info 	*info = dev->driver_info;
		int			retval = 0;

		clear_bit (EVENT_LINK_RESET, &dev->flags);
		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
			devinfo(dev, "link reset failed (%d) usbnet usb-%s-%s, %s",
				retval,
				dev->udev->bus->bus_name, dev->udev->devpath,
				info->description);
		}
	}

	if (dev->flags)
		devdbg (dev, "kevent done, flags = 0x%lx",
			dev->flags);
}

/*-------------------------------------------------------------------------*/

static void tx_complete (struct urb *urb, struct pt_regs *regs)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;

	if (urb->status == 0) {
		dev->stats.tx_packets++;
		dev->stats.tx_bytes += entry->length;
	} else {
		dev->stats.tx_errors++;

		switch (urb->status) {
		case -EPIPE:
			usbnet_defer_kevent (dev, EVENT_TX_HALT);
			break;

		/* software-driven interface shutdown */
		case -ECONNRESET:		// async unlink
		case -ESHUTDOWN:		// hardware gone
			break;

		// like rx, tx gets controller i/o faults during khubd delays
		// and so it uses the same throttling mechanism.
		case -EPROTO:		// ehci
		case -ETIMEDOUT:	// ohci
		case -EILSEQ:		// uhci
			if (!timer_pending (&dev->delay)) {
				mod_timer (&dev->delay,
					jiffies + THROTTLE_JIFFIES);
				if (netif_msg_link (dev))
					devdbg (dev, "tx throttle %d",
							urb->status);
			}
			netif_stop_queue (dev->net);
			break;
		default:
			if (netif_msg_tx_err (dev))
				devdbg (dev, "tx err %d", entry->urb->status);
			break;
		}
	}

	urb->dev = NULL;
	entry->state = tx_done;
	defer_bh(dev, skb, &dev->txq);
}

/*-------------------------------------------------------------------------*/

static void usbnet_tx_timeout (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);

	unlink_urbs (dev, &dev->txq);
	tasklet_schedule (&dev->bh);

	// FIXME: device recovery -- reset?
}

/*-------------------------------------------------------------------------*/

static int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			length;
	int			retval = NET_XMIT_SUCCESS;
	struct urb		*urb = NULL;
	struct skb_data		*entry;
	struct driver_info	*info = dev->driver_info;