Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
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
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Authors:	Sjur Brendeland/sjur.brandeland@stericsson.com
 *		Daniel Martensson / Daniel.Martensson@stericsson.com
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/fs.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/moduleparam.h>
#include <linux/ip.h>
#include <linux/sched.h>
#include <linux/sockios.h>
#include <linux/caif/if_caif.h>
#include <net/rtnetlink.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/caif_dev.h>

/* GPRS PDP connection has MTU to 1500 */
#define GPRS_PDP_MTU 1500
/* 5 sec. connect timeout */
#define CONNECT_TIMEOUT (5 * HZ)
#define CAIF_NET_DEFAULT_QUEUE_LEN 500
#define UNDEF_CONNID 0xffffffff

/*This list is protected by the rtnl lock. */
static LIST_HEAD(chnl_net_list);

MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK("caif");

enum caif_states {
	CAIF_CONNECTED		= 1,
	CAIF_CONNECTING,
	CAIF_DISCONNECTED,
	CAIF_SHUTDOWN
};

struct chnl_net {
	struct cflayer chnl;
	struct net_device_stats stats;
	struct caif_connect_request conn_req;
	struct list_head list_field;
	struct net_device *netdev;
	char name[256];
	wait_queue_head_t netmgmt_wq;
	/* Flow status to remember and control the transmission. */
	bool flowenabled;
	enum caif_states state;
};

static void robust_list_del(struct list_head *delete_node)
{
	struct list_head *list_node;
	struct list_head *n;
	ASSERT_RTNL();
	list_for_each_safe(list_node, n, &chnl_net_list) {
		if (list_node == delete_node) {
			list_del(list_node);
			return;
		}
	}
	WARN_ON(1);
}

static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
{
	struct sk_buff *skb;
	struct chnl_net *priv;
	int pktlen;
	const u8 *ip_version;
	u8 buf;

	priv = container_of(layr, struct chnl_net, chnl);
	if (!priv)
		return -EINVAL;

	skb = (struct sk_buff *) cfpkt_tonative(pkt);

	/* Get length of CAIF packet. */
	pktlen = skb->len;

	/* Pass some minimum information and
	 * send the packet to the net stack.
	 */
	skb->dev = priv->netdev;

	/* check the version of IP */
	ip_version = skb_header_pointer(skb, 0, 1, &buf);
	if (!ip_version) {
		kfree_skb(skb);
		return -EINVAL;
	}

	switch (*ip_version >> 4) {
	case 4:
		skb->protocol = htons(ETH_P_IP);
		break;
	case 6:
		skb->protocol = htons(ETH_P_IPV6);
		break;
	default:
		kfree_skb(skb);
		priv->netdev->stats.rx_errors++;
		return -EINVAL;
	}

	/* If we change the header in loop mode, the checksum is corrupted. */
	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	else
		skb->ip_summed = CHECKSUM_NONE;

	if (in_interrupt())
		netif_rx(skb);
	else
		netif_rx_ni(skb);

	/* Update statistics. */
	priv->netdev->stats.rx_packets++;
	priv->netdev->stats.rx_bytes += pktlen;

	return 0;
}

static int delete_device(struct chnl_net *dev)
{
	ASSERT_RTNL();
	if (dev->netdev)
		unregister_netdevice(dev->netdev);
	return 0;
}

static void close_work(struct work_struct *work)
{
	struct chnl_net *dev = NULL;
	struct list_head *list_node;
	struct list_head *_tmp;

	rtnl_lock();
	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
		dev = list_entry(list_node, struct chnl_net, list_field);
		if (dev->state == CAIF_SHUTDOWN)
			dev_close(dev->netdev);
	}
	rtnl_unlock();
}
static DECLARE_WORK(close_worker, close_work);

static void chnl_hold(struct cflayer *lyr)
{
	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
	dev_hold(priv->netdev);
}

static void chnl_put(struct cflayer *lyr)
{
	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
	dev_put(priv->netdev);
}

static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
				int phyid)
{
	struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
	pr_debug("NET flowctrl func called flow: %s\n",
		flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
		flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
		flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
		flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
		flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
		flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
		 "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");



	switch (flow) {
	case CAIF_CTRLCMD_FLOW_OFF_IND:
		priv->flowenabled = false;
		netif_stop_queue(priv->netdev);
		break;
	case CAIF_CTRLCMD_DEINIT_RSP:
		priv->state = CAIF_DISCONNECTED;
		break;
	case CAIF_CTRLCMD_INIT_FAIL_RSP:
		priv->state = CAIF_DISCONNECTED;
		wake_up_interruptible(&priv->netmgmt_wq);
		break;
	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
		priv->state = CAIF_SHUTDOWN;
		netif_tx_disable(priv->netdev);
		schedule_work(&close_worker);
		break;
	case CAIF_CTRLCMD_FLOW_ON_IND:
		priv->flowenabled = true;
		netif_wake_queue(priv->netdev);
		break;
	case CAIF_CTRLCMD_INIT_RSP:
		caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
		priv->state = CAIF_CONNECTED;
		priv->flowenabled = true;
		netif_wake_queue(priv->netdev);
		wake_up_interruptible(&priv->netmgmt_wq);
		break;
	default:
		break;
	}
}

static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct chnl_net *priv;
	struct cfpkt *pkt = NULL;
	int len;
	int result = -1;
	/* Get our private data. */
	priv = netdev_priv(dev);

	if (skb->len > priv->netdev->mtu) {
		pr_warn("Size of skb exceeded MTU\n");
		kfree_skb(skb);
		dev->stats.tx_errors++;
		return NETDEV_TX_OK;
	}

	if (!priv->flowenabled) {
		pr_debug("dropping packets flow off\n");
		kfree_skb(skb);
		dev->stats.tx_dropped++;
		return NETDEV_TX_OK;
	}

	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
		swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);

	/* Store original SKB length. */
	len = skb->len;

	pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);

	/* Send the packet down the stack. */
	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
	if (result) {
		dev->stats.tx_dropped++;
		return NETDEV_TX_OK;
	}

	/* Update statistics. */
	dev->stats.tx_packets++;
	dev->stats.tx_bytes += len;

	return NETDEV_TX_OK;
}

static int chnl_net_open(struct net_device *dev)
{
	struct chnl_net *priv = NULL;
	int result = -1;
	int llifindex, headroom, tailroom, mtu;
	struct net_device *lldev;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	if (!priv) {
		pr_debug("chnl_net_open: no priv\n");
		return -ENODEV;
	}

	if (priv->state != CAIF_CONNECTING) {
		priv->state = CAIF_CONNECTING;
		result = caif_connect_client(dev_net(dev), &priv->conn_req,
						&priv->chnl, &llifindex,
						&headroom, &tailroom);
		if (result != 0) {
				pr_debug("err: "
					 "Unable to register and open device,"
					 " Err:%d\n",
					 result);
				goto error;
		}

		lldev = dev_get_by_index(dev_net(dev), llifindex);

		if (lldev == NULL) {
			pr_debug("no interface?\n");
			result = -ENODEV;
			goto error;
		}

		dev->needed_tailroom = tailroom + lldev->needed_tailroom;
		dev->hard_header_len = headroom + lldev->hard_header_len +
			lldev->needed_tailroom;

		/*
		 * MTU, head-room etc is not know before we have a
		 * CAIF link layer device available. MTU calculation may
		 * override initial RTNL configuration.
		 * MTU is minimum of current mtu, link layer mtu pluss
		 * CAIF head and tail, and PDP GPRS contexts max MTU.
		 */
		mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
		mtu = min_t(int, GPRS_PDP_MTU, mtu);
		dev_set_mtu(dev, mtu);
		dev_put(lldev);

		if (mtu < 100) {
			pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
			result = -ENODEV;
			goto error;
		}
	}

	rtnl_unlock();  /* Release RTNL lock during connect wait */

	result = wait_event_interruptible_timeout(priv->netmgmt_wq,
						priv->state != CAIF_CONNECTING,
						CONNECT_TIMEOUT);

	rtnl_lock();

	if (result == -ERESTARTSYS) {
		pr_debug("wait_event_interruptible woken by a signal\n");
		result = -ERESTARTSYS;
		goto error;
	}

	if (result == 0) {
		pr_debug("connect timeout\n");
		caif_disconnect_client(dev_net(dev), &priv->chnl);
		priv->state = CAIF_DISCONNECTED;
		pr_debug("state disconnected\n");
		result = -ETIMEDOUT;
		goto error;
	}

	if (priv->state != CAIF_CONNECTED) {
		pr_debug("connect failed\n");
		result = -ECONNREFUSED;
		goto error;
	}
	pr_debug("CAIF Netdevice connected\n");
	return 0;

error:
	caif_disconnect_client(dev_net(dev), &priv->chnl);
	priv->state = CAIF_DISCONNECTED;
	pr_debug("state disconnected\n");
	return result;

}

static int chnl_net_stop(struct net_device *dev)
{
	struct chnl_net *priv;

	ASSERT_RTNL();
	priv = netdev_priv(dev);
	priv->state = CAIF_DISCONNECTED;
	caif_disconnect_client(dev_net(dev), &priv->chnl);
	return 0;
}

static int chnl_net_init(struct net_device *dev)
{
	struct chnl_net *priv;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	strncpy(priv->name, dev->name, sizeof(priv->name));
	return 0;
}

static void chnl_net_uninit(struct net_device *dev)
{
	struct chnl_net *priv;
	ASSERT_RTNL();
	priv = netdev_priv(dev);
	robust_list_del(&priv->list_field);
}

static const struct net_device_ops netdev_ops = {
	.ndo_open = chnl_net_open,
	.ndo_stop = chnl_net_stop,
	.ndo_init = chnl_net_init,
	.ndo_uninit = chnl_net_uninit,
	.ndo_start_xmit = chnl_net_start_xmit,
};

static void chnl_net_destructor(struct net_device *dev)
{
	struct chnl_net *priv = netdev_priv(dev);
	caif_free_client(&priv->chnl);
	free_netdev(dev);
}

static void ipcaif_net_setup(struct net_device *dev)
{
	struct chnl_net *priv;
	dev->netdev_ops = &netdev_ops;
	dev->destructor = chnl_net_destructor;
	dev->flags |= IFF_NOARP;
	dev->flags |= IFF_POINTOPOINT;
	dev->mtu = GPRS_PDP_MTU;
	dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;

	priv = netdev_priv(dev);
	priv->chnl.receive = chnl_recv_cb;
	priv->chnl.ctrlcmd = chnl_flowctrl_cb;
	priv->netdev = dev;
	priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
	priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
	priv->conn_req.priority = CAIF_PRIO_LOW;
	/* Insert illegal value */
	priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
	priv->flowenabled = false;

	init_waitqueue_head(&priv->netmgmt_wq);
}


static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
	struct chnl_net *priv;
	u8 loop;
	priv = netdev_priv(dev);
	if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
			priv->conn_req.sockaddr.u.dgm.connection_id) ||
	    nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
			priv->conn_req.sockaddr.u.dgm.connection_id))
		goto nla_put_failure;
	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
	if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
		goto nla_put_failure;
	return 0;
nla_put_failure:
	return -EMSGSIZE;

}

static void caif_netlink_parms(struct nlattr *data[],
				struct caif_connect_request *conn_req)
{
	if (!data) {
		pr_warn("no params data found\n");
		return;
	}
	if (data[IFLA_CAIF_IPV4_CONNID])
		conn_req->sockaddr.u.dgm.connection_id =
			nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
	if (data[IFLA_CAIF_IPV6_CONNID])
		conn_req->sockaddr.u.dgm.connection_id =
			nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
	if (data[IFLA_CAIF_LOOPBACK]) {
		if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
			conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
		else
			conn_req->protocol = CAIFPROTO_DATAGRAM;
	}
}

static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
			  struct nlattr *tb[], struct nlattr *data[])
{
	int ret;
	struct chnl_net *caifdev;
	ASSERT_RTNL();
	caifdev = netdev_priv(dev);
	caif_netlink_parms(data, &caifdev->conn_req);
	dev_net_set(caifdev->netdev, src_net);

	ret = register_netdevice(dev);
	if (ret)
		pr_warn("device rtml registration failed\n");
	else
		list_add(&caifdev->list_field, &chnl_net_list);

	/* Use ifindex as connection id, and use loopback channel default. */
	if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
		caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
		caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
	}
	return ret;
}

static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
				struct nlattr *data[])
{
	struct chnl_net *caifdev;
	ASSERT_RTNL();
	caifdev = netdev_priv(dev);
	caif_netlink_parms(data, &caifdev->conn_req);
	netdev_state_change(dev);
	return 0;
}

static size_t ipcaif_get_size(const struct net_device *dev)
{
	return
		/* IFLA_CAIF_IPV4_CONNID */
		nla_total_size(4) +
		/* IFLA_CAIF_IPV6_CONNID */
		nla_total_size(4) +
		/* IFLA_CAIF_LOOPBACK */
		nla_total_size(2) +
		0;
}

static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
	[IFLA_CAIF_IPV4_CONNID]	      = { .type = NLA_U32 },
	[IFLA_CAIF_IPV6_CONNID]	      = { .type = NLA_U32 },
	[IFLA_CAIF_LOOPBACK]	      = { .type = NLA_U8 }
};


static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
	.kind		= "caif",
	.priv_size	= sizeof(struct chnl_net),
	.setup		= ipcaif_net_setup,
	.maxtype	= IFLA_CAIF_MAX,
	.policy		= ipcaif_policy,
	.newlink	= ipcaif_newlink,
	.changelink	= ipcaif_changelink,
	.get_size	= ipcaif_get_size,
	.fill_info	= ipcaif_fill_info,

};

static int __init chnl_init_module(void)
{
	return rtnl_link_register(&ipcaif_link_ops);
}

static void __exit chnl_exit_module(void)
{
	struct chnl_net *dev = NULL;
	struct list_head *list_node;
	struct list_head *_tmp;
	rtnl_link_unregister(&ipcaif_link_ops);
	rtnl_lock();
	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
		dev = list_entry(list_node, struct chnl_net, list_field);
		list_del(list_node);
		delete_device(dev);
	}
	rtnl_unlock();
}

module_init(chnl_init_module);
module_exit(chnl_exit_module);