1/*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Authors:	Sjur Brendeland
4 *		Daniel Martensson
5 * License terms: GNU General Public License (GPL) version 2
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
9
10#include <linux/fs.h>
11#include <linux/hardirq.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/netdevice.h>
15#include <linux/if_ether.h>
16#include <linux/moduleparam.h>
17#include <linux/ip.h>
18#include <linux/sched.h>
19#include <linux/sockios.h>
20#include <linux/caif/if_caif.h>
21#include <net/rtnetlink.h>
22#include <net/caif/caif_layer.h>
23#include <net/caif/cfpkt.h>
24#include <net/caif/caif_dev.h>
25
26/* GPRS PDP connection has MTU to 1500 */
27#define GPRS_PDP_MTU 1500
28/* 5 sec. connect timeout */
29#define CONNECT_TIMEOUT (5 * HZ)
30#define CAIF_NET_DEFAULT_QUEUE_LEN 500
31#define UNDEF_CONNID 0xffffffff
32
33/*This list is protected by the rtnl lock. */
34static LIST_HEAD(chnl_net_list);
35
36MODULE_LICENSE("GPL");
37MODULE_ALIAS_RTNL_LINK("caif");
38
39enum caif_states {
40	CAIF_CONNECTED		= 1,
41	CAIF_CONNECTING,
42	CAIF_DISCONNECTED,
43	CAIF_SHUTDOWN
44};
45
46struct chnl_net {
47	struct cflayer chnl;
48	struct net_device_stats stats;
49	struct caif_connect_request conn_req;
50	struct list_head list_field;
51	struct net_device *netdev;
52	char name[256];
53	wait_queue_head_t netmgmt_wq;
54	/* Flow status to remember and control the transmission. */
55	bool flowenabled;
56	enum caif_states state;
57};
58
59static void robust_list_del(struct list_head *delete_node)
60{
61	struct list_head *list_node;
62	struct list_head *n;
63	ASSERT_RTNL();
64	list_for_each_safe(list_node, n, &chnl_net_list) {
65		if (list_node == delete_node) {
66			list_del(list_node);
67			return;
68		}
69	}
70	WARN_ON(1);
71}
72
73static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
74{
75	struct sk_buff *skb;
76	struct chnl_net *priv;
77	int pktlen;
78	const u8 *ip_version;
79	u8 buf;
80
81	priv = container_of(layr, struct chnl_net, chnl);
82	if (!priv)
83		return -EINVAL;
84
85	skb = (struct sk_buff *) cfpkt_tonative(pkt);
86
87	/* Get length of CAIF packet. */
88	pktlen = skb->len;
89
90	/* Pass some minimum information and
91	 * send the packet to the net stack.
92	 */
93	skb->dev = priv->netdev;
94
95	/* check the version of IP */
96	ip_version = skb_header_pointer(skb, 0, 1, &buf);
97	if (!ip_version) {
98		kfree_skb(skb);
99		return -EINVAL;
100	}
101
102	switch (*ip_version >> 4) {
103	case 4:
104		skb->protocol = htons(ETH_P_IP);
105		break;
106	case 6:
107		skb->protocol = htons(ETH_P_IPV6);
108		break;
109	default:
110		kfree_skb(skb);
111		priv->netdev->stats.rx_errors++;
112		return -EINVAL;
113	}
114
115	/* If we change the header in loop mode, the checksum is corrupted. */
116	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
117		skb->ip_summed = CHECKSUM_UNNECESSARY;
118	else
119		skb->ip_summed = CHECKSUM_NONE;
120
121	if (in_interrupt())
122		netif_rx(skb);
123	else
124		netif_rx_ni(skb);
125
126	/* Update statistics. */
127	priv->netdev->stats.rx_packets++;
128	priv->netdev->stats.rx_bytes += pktlen;
129
130	return 0;
131}
132
133static int delete_device(struct chnl_net *dev)
134{
135	ASSERT_RTNL();
136	if (dev->netdev)
137		unregister_netdevice(dev->netdev);
138	return 0;
139}
140
141static void close_work(struct work_struct *work)
142{
143	struct chnl_net *dev = NULL;
144	struct list_head *list_node;
145	struct list_head *_tmp;
146
147	rtnl_lock();
148	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
149		dev = list_entry(list_node, struct chnl_net, list_field);
150		if (dev->state == CAIF_SHUTDOWN)
151			dev_close(dev->netdev);
152	}
153	rtnl_unlock();
154}
155static DECLARE_WORK(close_worker, close_work);
156
157static void chnl_hold(struct cflayer *lyr)
158{
159	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
160	dev_hold(priv->netdev);
161}
162
163static void chnl_put(struct cflayer *lyr)
164{
165	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
166	dev_put(priv->netdev);
167}
168
169static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
170			     int phyid)
171{
172	struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
173	pr_debug("NET flowctrl func called flow: %s\n",
174		flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
175		flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
176		flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
177		flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
178		flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
179		flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
180		 "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
181
182
183
184	switch (flow) {
185	case CAIF_CTRLCMD_FLOW_OFF_IND:
186		priv->flowenabled = false;
187		netif_stop_queue(priv->netdev);
188		break;
189	case CAIF_CTRLCMD_DEINIT_RSP:
190		priv->state = CAIF_DISCONNECTED;
191		break;
192	case CAIF_CTRLCMD_INIT_FAIL_RSP:
193		priv->state = CAIF_DISCONNECTED;
194		wake_up_interruptible(&priv->netmgmt_wq);
195		break;
196	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
197		priv->state = CAIF_SHUTDOWN;
198		netif_tx_disable(priv->netdev);
199		schedule_work(&close_worker);
200		break;
201	case CAIF_CTRLCMD_FLOW_ON_IND:
202		priv->flowenabled = true;
203		netif_wake_queue(priv->netdev);
204		break;
205	case CAIF_CTRLCMD_INIT_RSP:
206		caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
207		priv->state = CAIF_CONNECTED;
208		priv->flowenabled = true;
209		netif_wake_queue(priv->netdev);
210		wake_up_interruptible(&priv->netmgmt_wq);
211		break;
212	default:
213		break;
214	}
215}
216
217static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
218{
219	struct chnl_net *priv;
220	struct cfpkt *pkt = NULL;
221	int len;
222	int result = -1;
223	/* Get our private data. */
224	priv = netdev_priv(dev);
225
226	if (skb->len > priv->netdev->mtu) {
227		pr_warn("Size of skb exceeded MTU\n");
228		kfree_skb(skb);
229		dev->stats.tx_errors++;
230		return NETDEV_TX_OK;
231	}
232
233	if (!priv->flowenabled) {
234		pr_debug("dropping packets flow off\n");
235		kfree_skb(skb);
236		dev->stats.tx_dropped++;
237		return NETDEV_TX_OK;
238	}
239
240	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
241		swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
242
243	/* Store original SKB length. */
244	len = skb->len;
245
246	pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
247
248	/* Send the packet down the stack. */
249	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
250	if (result) {
251		dev->stats.tx_dropped++;
252		return NETDEV_TX_OK;
253	}
254
255	/* Update statistics. */
256	dev->stats.tx_packets++;
257	dev->stats.tx_bytes += len;
258
259	return NETDEV_TX_OK;
260}
261
262static int chnl_net_open(struct net_device *dev)
263{
264	struct chnl_net *priv = NULL;
265	int result = -1;
266	int llifindex, headroom, tailroom, mtu;
267	struct net_device *lldev;
268	ASSERT_RTNL();
269	priv = netdev_priv(dev);
270	if (!priv) {
271		pr_debug("chnl_net_open: no priv\n");
272		return -ENODEV;
273	}
274
275	if (priv->state != CAIF_CONNECTING) {
276		priv->state = CAIF_CONNECTING;
277		result = caif_connect_client(dev_net(dev), &priv->conn_req,
278						&priv->chnl, &llifindex,
279						&headroom, &tailroom);
280		if (result != 0) {
281				pr_debug("err: "
282					 "Unable to register and open device,"
283					 " Err:%d\n",
284					 result);
285				goto error;
286		}
287
288		lldev = __dev_get_by_index(dev_net(dev), llifindex);
289
290		if (lldev == NULL) {
291			pr_debug("no interface?\n");
292			result = -ENODEV;
293			goto error;
294		}
295
296		dev->needed_tailroom = tailroom + lldev->needed_tailroom;
297		dev->hard_header_len = headroom + lldev->hard_header_len +
298			lldev->needed_tailroom;
299
300		/*
301		 * MTU, head-room etc is not know before we have a
302		 * CAIF link layer device available. MTU calculation may
303		 * override initial RTNL configuration.
304		 * MTU is minimum of current mtu, link layer mtu pluss
305		 * CAIF head and tail, and PDP GPRS contexts max MTU.
306		 */
307		mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
308		mtu = min_t(int, GPRS_PDP_MTU, mtu);
309		dev_set_mtu(dev, mtu);
310
311		if (mtu < 100) {
312			pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
313			result = -ENODEV;
314			goto error;
315		}
316	}
317
318	rtnl_unlock();  /* Release RTNL lock during connect wait */
319
320	result = wait_event_interruptible_timeout(priv->netmgmt_wq,
321						priv->state != CAIF_CONNECTING,
322						CONNECT_TIMEOUT);
323
324	rtnl_lock();
325
326	if (result == -ERESTARTSYS) {
327		pr_debug("wait_event_interruptible woken by a signal\n");
328		result = -ERESTARTSYS;
329		goto error;
330	}
331
332	if (result == 0) {
333		pr_debug("connect timeout\n");
334		caif_disconnect_client(dev_net(dev), &priv->chnl);
335		priv->state = CAIF_DISCONNECTED;
336		pr_debug("state disconnected\n");
337		result = -ETIMEDOUT;
338		goto error;
339	}
340
341	if (priv->state != CAIF_CONNECTED) {
342		pr_debug("connect failed\n");
343		result = -ECONNREFUSED;
344		goto error;
345	}
346	pr_debug("CAIF Netdevice connected\n");
347	return 0;
348
349error:
350	caif_disconnect_client(dev_net(dev), &priv->chnl);
351	priv->state = CAIF_DISCONNECTED;
352	pr_debug("state disconnected\n");
353	return result;
354
355}
356
357static int chnl_net_stop(struct net_device *dev)
358{
359	struct chnl_net *priv;
360
361	ASSERT_RTNL();
362	priv = netdev_priv(dev);
363	priv->state = CAIF_DISCONNECTED;
364	caif_disconnect_client(dev_net(dev), &priv->chnl);
365	return 0;
366}
367
368static int chnl_net_init(struct net_device *dev)
369{
370	struct chnl_net *priv;
371	ASSERT_RTNL();
372	priv = netdev_priv(dev);
373	strncpy(priv->name, dev->name, sizeof(priv->name));
374	return 0;
375}
376
377static void chnl_net_uninit(struct net_device *dev)
378{
379	struct chnl_net *priv;
380	ASSERT_RTNL();
381	priv = netdev_priv(dev);
382	robust_list_del(&priv->list_field);
383}
384
385static const struct net_device_ops netdev_ops = {
386	.ndo_open = chnl_net_open,
387	.ndo_stop = chnl_net_stop,
388	.ndo_init = chnl_net_init,
389	.ndo_uninit = chnl_net_uninit,
390	.ndo_start_xmit = chnl_net_start_xmit,
391};
392
393static void chnl_net_destructor(struct net_device *dev)
394{
395	struct chnl_net *priv = netdev_priv(dev);
396	caif_free_client(&priv->chnl);
397	free_netdev(dev);
398}
399
400static void ipcaif_net_setup(struct net_device *dev)
401{
402	struct chnl_net *priv;
403	dev->netdev_ops = &netdev_ops;
404	dev->destructor = chnl_net_destructor;
405	dev->flags |= IFF_NOARP;
406	dev->flags |= IFF_POINTOPOINT;
407	dev->mtu = GPRS_PDP_MTU;
408	dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
409
410	priv = netdev_priv(dev);
411	priv->chnl.receive = chnl_recv_cb;
412	priv->chnl.ctrlcmd = chnl_flowctrl_cb;
413	priv->netdev = dev;
414	priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
415	priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
416	priv->conn_req.priority = CAIF_PRIO_LOW;
417	/* Insert illegal value */
418	priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
419	priv->flowenabled = false;
420
421	init_waitqueue_head(&priv->netmgmt_wq);
422}
423
424
425static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
426{
427	struct chnl_net *priv;
428	u8 loop;
429	priv = netdev_priv(dev);
430	if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
431			priv->conn_req.sockaddr.u.dgm.connection_id) ||
432	    nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
433			priv->conn_req.sockaddr.u.dgm.connection_id))
434		goto nla_put_failure;
435	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
436	if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
437		goto nla_put_failure;
438	return 0;
439nla_put_failure:
440	return -EMSGSIZE;
441
442}
443
444static void caif_netlink_parms(struct nlattr *data[],
445			       struct caif_connect_request *conn_req)
446{
447	if (!data) {
448		pr_warn("no params data found\n");
449		return;
450	}
451	if (data[IFLA_CAIF_IPV4_CONNID])
452		conn_req->sockaddr.u.dgm.connection_id =
453			nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
454	if (data[IFLA_CAIF_IPV6_CONNID])
455		conn_req->sockaddr.u.dgm.connection_id =
456			nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
457	if (data[IFLA_CAIF_LOOPBACK]) {
458		if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
459			conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
460		else
461			conn_req->protocol = CAIFPROTO_DATAGRAM;
462	}
463}
464
465static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
466			  struct nlattr *tb[], struct nlattr *data[])
467{
468	int ret;
469	struct chnl_net *caifdev;
470	ASSERT_RTNL();
471	caifdev = netdev_priv(dev);
472	caif_netlink_parms(data, &caifdev->conn_req);
473
474	ret = register_netdevice(dev);
475	if (ret)
476		pr_warn("device rtml registration failed\n");
477	else
478		list_add(&caifdev->list_field, &chnl_net_list);
479
480	/* Use ifindex as connection id, and use loopback channel default. */
481	if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
482		caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
483		caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
484	}
485	return ret;
486}
487
488static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
489			     struct nlattr *data[])
490{
491	struct chnl_net *caifdev;
492	ASSERT_RTNL();
493	caifdev = netdev_priv(dev);
494	caif_netlink_parms(data, &caifdev->conn_req);
495	netdev_state_change(dev);
496	return 0;
497}
498
499static size_t ipcaif_get_size(const struct net_device *dev)
500{
501	return
502		/* IFLA_CAIF_IPV4_CONNID */
503		nla_total_size(4) +
504		/* IFLA_CAIF_IPV6_CONNID */
505		nla_total_size(4) +
506		/* IFLA_CAIF_LOOPBACK */
507		nla_total_size(2) +
508		0;
509}
510
511static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
512	[IFLA_CAIF_IPV4_CONNID]	      = { .type = NLA_U32 },
513	[IFLA_CAIF_IPV6_CONNID]	      = { .type = NLA_U32 },
514	[IFLA_CAIF_LOOPBACK]	      = { .type = NLA_U8 }
515};
516
517
518static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
519	.kind		= "caif",
520	.priv_size	= sizeof(struct chnl_net),
521	.setup		= ipcaif_net_setup,
522	.maxtype	= IFLA_CAIF_MAX,
523	.policy		= ipcaif_policy,
524	.newlink	= ipcaif_newlink,
525	.changelink	= ipcaif_changelink,
526	.get_size	= ipcaif_get_size,
527	.fill_info	= ipcaif_fill_info,
528
529};
530
531static int __init chnl_init_module(void)
532{
533	return rtnl_link_register(&ipcaif_link_ops);
534}
535
536static void __exit chnl_exit_module(void)
537{
538	struct chnl_net *dev = NULL;
539	struct list_head *list_node;
540	struct list_head *_tmp;
541	rtnl_link_unregister(&ipcaif_link_ops);
542	rtnl_lock();
543	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
544		dev = list_entry(list_node, struct chnl_net, list_field);
545		list_del(list_node);
546		delete_device(dev);
547	}
548	rtnl_unlock();
549}
550
551module_init(chnl_init_module);
552module_exit(chnl_exit_module);
553