xref: /kernel/linux/linux-5.10/net/caif/chnl_net.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) ST-Ericsson AB 2010
4 * Authors:	Sjur Brendeland
5 *		Daniel Martensson
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
9
10#include <linux/fs.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/netdevice.h>
14#include <linux/if_ether.h>
15#include <linux/ip.h>
16#include <linux/sched.h>
17#include <linux/sockios.h>
18#include <linux/caif/if_caif.h>
19#include <net/rtnetlink.h>
20#include <net/caif/caif_layer.h>
21#include <net/caif/cfpkt.h>
22#include <net/caif/caif_dev.h>
23
24/* GPRS PDP connection has MTU to 1500 */
25#define GPRS_PDP_MTU 1500
26/* 5 sec. connect timeout */
27#define CONNECT_TIMEOUT (5 * HZ)
28#define CAIF_NET_DEFAULT_QUEUE_LEN 500
29#define UNDEF_CONNID 0xffffffff
30
31/*This list is protected by the rtnl lock. */
32static LIST_HEAD(chnl_net_list);
33
34MODULE_LICENSE("GPL");
35MODULE_ALIAS_RTNL_LINK("caif");
36
37enum caif_states {
38	CAIF_CONNECTED		= 1,
39	CAIF_CONNECTING,
40	CAIF_DISCONNECTED,
41	CAIF_SHUTDOWN
42};
43
44struct chnl_net {
45	struct cflayer chnl;
46	struct caif_connect_request conn_req;
47	struct list_head list_field;
48	struct net_device *netdev;
49	char name[256];
50	wait_queue_head_t netmgmt_wq;
51	/* Flow status to remember and control the transmission. */
52	bool flowenabled;
53	enum caif_states state;
54};
55
56static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
57{
58	struct sk_buff *skb;
59	struct chnl_net *priv;
60	int pktlen;
61	const u8 *ip_version;
62	u8 buf;
63
64	priv = container_of(layr, struct chnl_net, chnl);
65	if (!priv)
66		return -EINVAL;
67
68	skb = (struct sk_buff *) cfpkt_tonative(pkt);
69
70	/* Get length of CAIF packet. */
71	pktlen = skb->len;
72
73	/* Pass some minimum information and
74	 * send the packet to the net stack.
75	 */
76	skb->dev = priv->netdev;
77
78	/* check the version of IP */
79	ip_version = skb_header_pointer(skb, 0, 1, &buf);
80	if (!ip_version) {
81		kfree_skb(skb);
82		return -EINVAL;
83	}
84
85	switch (*ip_version >> 4) {
86	case 4:
87		skb->protocol = htons(ETH_P_IP);
88		break;
89	case 6:
90		skb->protocol = htons(ETH_P_IPV6);
91		break;
92	default:
93		kfree_skb(skb);
94		priv->netdev->stats.rx_errors++;
95		return -EINVAL;
96	}
97
98	/* If we change the header in loop mode, the checksum is corrupted. */
99	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
100		skb->ip_summed = CHECKSUM_UNNECESSARY;
101	else
102		skb->ip_summed = CHECKSUM_NONE;
103
104	if (in_interrupt())
105		netif_rx(skb);
106	else
107		netif_rx_ni(skb);
108
109	/* Update statistics. */
110	priv->netdev->stats.rx_packets++;
111	priv->netdev->stats.rx_bytes += pktlen;
112
113	return 0;
114}
115
116static int delete_device(struct chnl_net *dev)
117{
118	ASSERT_RTNL();
119	if (dev->netdev)
120		unregister_netdevice(dev->netdev);
121	return 0;
122}
123
124static void close_work(struct work_struct *work)
125{
126	struct chnl_net *dev = NULL;
127	struct list_head *list_node;
128	struct list_head *_tmp;
129
130	rtnl_lock();
131	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
132		dev = list_entry(list_node, struct chnl_net, list_field);
133		if (dev->state == CAIF_SHUTDOWN)
134			dev_close(dev->netdev);
135	}
136	rtnl_unlock();
137}
138static DECLARE_WORK(close_worker, close_work);
139
140static void chnl_hold(struct cflayer *lyr)
141{
142	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
143	dev_hold(priv->netdev);
144}
145
146static void chnl_put(struct cflayer *lyr)
147{
148	struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
149	dev_put(priv->netdev);
150}
151
152static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
153			     int phyid)
154{
155	struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
156	pr_debug("NET flowctrl func called flow: %s\n",
157		flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
158		flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
159		flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
160		flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
161		flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
162		flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
163		 "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
164
165
166
167	switch (flow) {
168	case CAIF_CTRLCMD_FLOW_OFF_IND:
169		priv->flowenabled = false;
170		netif_stop_queue(priv->netdev);
171		break;
172	case CAIF_CTRLCMD_DEINIT_RSP:
173		priv->state = CAIF_DISCONNECTED;
174		break;
175	case CAIF_CTRLCMD_INIT_FAIL_RSP:
176		priv->state = CAIF_DISCONNECTED;
177		wake_up_interruptible(&priv->netmgmt_wq);
178		break;
179	case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
180		priv->state = CAIF_SHUTDOWN;
181		netif_tx_disable(priv->netdev);
182		schedule_work(&close_worker);
183		break;
184	case CAIF_CTRLCMD_FLOW_ON_IND:
185		priv->flowenabled = true;
186		netif_wake_queue(priv->netdev);
187		break;
188	case CAIF_CTRLCMD_INIT_RSP:
189		caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
190		priv->state = CAIF_CONNECTED;
191		priv->flowenabled = true;
192		netif_wake_queue(priv->netdev);
193		wake_up_interruptible(&priv->netmgmt_wq);
194		break;
195	default:
196		break;
197	}
198}
199
200static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
201				       struct net_device *dev)
202{
203	struct chnl_net *priv;
204	struct cfpkt *pkt = NULL;
205	int len;
206	int result = -1;
207	/* Get our private data. */
208	priv = netdev_priv(dev);
209
210	if (skb->len > priv->netdev->mtu) {
211		pr_warn("Size of skb exceeded MTU\n");
212		kfree_skb(skb);
213		dev->stats.tx_errors++;
214		return NETDEV_TX_OK;
215	}
216
217	if (!priv->flowenabled) {
218		pr_debug("dropping packets flow off\n");
219		kfree_skb(skb);
220		dev->stats.tx_dropped++;
221		return NETDEV_TX_OK;
222	}
223
224	if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
225		swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
226
227	/* Store original SKB length. */
228	len = skb->len;
229
230	pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
231
232	/* Send the packet down the stack. */
233	result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
234	if (result) {
235		dev->stats.tx_dropped++;
236		return NETDEV_TX_OK;
237	}
238
239	/* Update statistics. */
240	dev->stats.tx_packets++;
241	dev->stats.tx_bytes += len;
242
243	return NETDEV_TX_OK;
244}
245
246static int chnl_net_open(struct net_device *dev)
247{
248	struct chnl_net *priv = NULL;
249	int result = -1;
250	int llifindex, headroom, tailroom, mtu;
251	struct net_device *lldev;
252	ASSERT_RTNL();
253	priv = netdev_priv(dev);
254	if (!priv) {
255		pr_debug("chnl_net_open: no priv\n");
256		return -ENODEV;
257	}
258
259	if (priv->state != CAIF_CONNECTING) {
260		priv->state = CAIF_CONNECTING;
261		result = caif_connect_client(dev_net(dev), &priv->conn_req,
262						&priv->chnl, &llifindex,
263						&headroom, &tailroom);
264		if (result != 0) {
265				pr_debug("err: "
266					 "Unable to register and open device,"
267					 " Err:%d\n",
268					 result);
269				goto error;
270		}
271
272		lldev = __dev_get_by_index(dev_net(dev), llifindex);
273
274		if (lldev == NULL) {
275			pr_debug("no interface?\n");
276			result = -ENODEV;
277			goto error;
278		}
279
280		dev->needed_tailroom = tailroom + lldev->needed_tailroom;
281		dev->hard_header_len = headroom + lldev->hard_header_len +
282			lldev->needed_tailroom;
283
284		/*
285		 * MTU, head-room etc is not know before we have a
286		 * CAIF link layer device available. MTU calculation may
287		 * override initial RTNL configuration.
288		 * MTU is minimum of current mtu, link layer mtu pluss
289		 * CAIF head and tail, and PDP GPRS contexts max MTU.
290		 */
291		mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
292		mtu = min_t(int, GPRS_PDP_MTU, mtu);
293		dev_set_mtu(dev, mtu);
294
295		if (mtu < 100) {
296			pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
297			result = -ENODEV;
298			goto error;
299		}
300	}
301
302	rtnl_unlock();  /* Release RTNL lock during connect wait */
303
304	result = wait_event_interruptible_timeout(priv->netmgmt_wq,
305						priv->state != CAIF_CONNECTING,
306						CONNECT_TIMEOUT);
307
308	rtnl_lock();
309
310	if (result == -ERESTARTSYS) {
311		pr_debug("wait_event_interruptible woken by a signal\n");
312		result = -ERESTARTSYS;
313		goto error;
314	}
315
316	if (result == 0) {
317		pr_debug("connect timeout\n");
318		result = -ETIMEDOUT;
319		goto error;
320	}
321
322	if (priv->state != CAIF_CONNECTED) {
323		pr_debug("connect failed\n");
324		result = -ECONNREFUSED;
325		goto error;
326	}
327	pr_debug("CAIF Netdevice connected\n");
328	return 0;
329
330error:
331	caif_disconnect_client(dev_net(dev), &priv->chnl);
332	priv->state = CAIF_DISCONNECTED;
333	pr_debug("state disconnected\n");
334	return result;
335
336}
337
338static int chnl_net_stop(struct net_device *dev)
339{
340	struct chnl_net *priv;
341
342	ASSERT_RTNL();
343	priv = netdev_priv(dev);
344	priv->state = CAIF_DISCONNECTED;
345	caif_disconnect_client(dev_net(dev), &priv->chnl);
346	return 0;
347}
348
349static int chnl_net_init(struct net_device *dev)
350{
351	struct chnl_net *priv;
352	ASSERT_RTNL();
353	priv = netdev_priv(dev);
354	strncpy(priv->name, dev->name, sizeof(priv->name));
355	INIT_LIST_HEAD(&priv->list_field);
356	return 0;
357}
358
359static void chnl_net_uninit(struct net_device *dev)
360{
361	struct chnl_net *priv;
362	ASSERT_RTNL();
363	priv = netdev_priv(dev);
364	list_del_init(&priv->list_field);
365}
366
367static const struct net_device_ops netdev_ops = {
368	.ndo_open = chnl_net_open,
369	.ndo_stop = chnl_net_stop,
370	.ndo_init = chnl_net_init,
371	.ndo_uninit = chnl_net_uninit,
372	.ndo_start_xmit = chnl_net_start_xmit,
373};
374
375static void chnl_net_destructor(struct net_device *dev)
376{
377	struct chnl_net *priv = netdev_priv(dev);
378	caif_free_client(&priv->chnl);
379}
380
381static void ipcaif_net_setup(struct net_device *dev)
382{
383	struct chnl_net *priv;
384	dev->netdev_ops = &netdev_ops;
385	dev->needs_free_netdev = true;
386	dev->priv_destructor = chnl_net_destructor;
387	dev->flags |= IFF_NOARP;
388	dev->flags |= IFF_POINTOPOINT;
389	dev->mtu = GPRS_PDP_MTU;
390	dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
391
392	priv = netdev_priv(dev);
393	priv->chnl.receive = chnl_recv_cb;
394	priv->chnl.ctrlcmd = chnl_flowctrl_cb;
395	priv->netdev = dev;
396	priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
397	priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
398	priv->conn_req.priority = CAIF_PRIO_LOW;
399	/* Insert illegal value */
400	priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
401	priv->flowenabled = false;
402
403	init_waitqueue_head(&priv->netmgmt_wq);
404}
405
406
407static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
408{
409	struct chnl_net *priv;
410	u8 loop;
411	priv = netdev_priv(dev);
412	if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
413			priv->conn_req.sockaddr.u.dgm.connection_id) ||
414	    nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
415			priv->conn_req.sockaddr.u.dgm.connection_id))
416		goto nla_put_failure;
417	loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
418	if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
419		goto nla_put_failure;
420	return 0;
421nla_put_failure:
422	return -EMSGSIZE;
423
424}
425
426static void caif_netlink_parms(struct nlattr *data[],
427			       struct caif_connect_request *conn_req)
428{
429	if (!data) {
430		pr_warn("no params data found\n");
431		return;
432	}
433	if (data[IFLA_CAIF_IPV4_CONNID])
434		conn_req->sockaddr.u.dgm.connection_id =
435			nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
436	if (data[IFLA_CAIF_IPV6_CONNID])
437		conn_req->sockaddr.u.dgm.connection_id =
438			nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
439	if (data[IFLA_CAIF_LOOPBACK]) {
440		if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
441			conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
442		else
443			conn_req->protocol = CAIFPROTO_DATAGRAM;
444	}
445}
446
447static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
448			  struct nlattr *tb[], struct nlattr *data[],
449			  struct netlink_ext_ack *extack)
450{
451	int ret;
452	struct chnl_net *caifdev;
453	ASSERT_RTNL();
454	caifdev = netdev_priv(dev);
455	caif_netlink_parms(data, &caifdev->conn_req);
456
457	ret = register_netdevice(dev);
458	if (ret)
459		pr_warn("device rtml registration failed\n");
460	else
461		list_add(&caifdev->list_field, &chnl_net_list);
462
463	/* Use ifindex as connection id, and use loopback channel default. */
464	if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
465		caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
466		caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
467	}
468	return ret;
469}
470
471static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
472			     struct nlattr *data[],
473			     struct netlink_ext_ack *extack)
474{
475	struct chnl_net *caifdev;
476	ASSERT_RTNL();
477	caifdev = netdev_priv(dev);
478	caif_netlink_parms(data, &caifdev->conn_req);
479	netdev_state_change(dev);
480	return 0;
481}
482
483static size_t ipcaif_get_size(const struct net_device *dev)
484{
485	return
486		/* IFLA_CAIF_IPV4_CONNID */
487		nla_total_size(4) +
488		/* IFLA_CAIF_IPV6_CONNID */
489		nla_total_size(4) +
490		/* IFLA_CAIF_LOOPBACK */
491		nla_total_size(2) +
492		0;
493}
494
495static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
496	[IFLA_CAIF_IPV4_CONNID]	      = { .type = NLA_U32 },
497	[IFLA_CAIF_IPV6_CONNID]	      = { .type = NLA_U32 },
498	[IFLA_CAIF_LOOPBACK]	      = { .type = NLA_U8 }
499};
500
501
502static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
503	.kind		= "caif",
504	.priv_size	= sizeof(struct chnl_net),
505	.setup		= ipcaif_net_setup,
506	.maxtype	= IFLA_CAIF_MAX,
507	.policy		= ipcaif_policy,
508	.newlink	= ipcaif_newlink,
509	.changelink	= ipcaif_changelink,
510	.get_size	= ipcaif_get_size,
511	.fill_info	= ipcaif_fill_info,
512
513};
514
515static int __init chnl_init_module(void)
516{
517	return rtnl_link_register(&ipcaif_link_ops);
518}
519
520static void __exit chnl_exit_module(void)
521{
522	struct chnl_net *dev = NULL;
523	struct list_head *list_node;
524	struct list_head *_tmp;
525	rtnl_link_unregister(&ipcaif_link_ops);
526	rtnl_lock();
527	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
528		dev = list_entry(list_node, struct chnl_net, list_field);
529		list_del_init(list_node);
530		delete_device(dev);
531	}
532	rtnl_unlock();
533}
534
535module_init(chnl_init_module);
536module_exit(chnl_exit_module);
537