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