xref: /linux/drivers/atm/atmtcp.c (revision 4b4193256c8d3bc3a5397b5cd9494c2ad386317d) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* drivers/atm/atmtcp.c - ATM over TCP "device" driver */
3 
4 /* Written 1997-2000 by Werner Almesberger, EPFL LRC/ICA */
5 
6 
7 #include <linux/module.h>
8 #include <linux/wait.h>
9 #include <linux/atmdev.h>
10 #include <linux/atm_tcp.h>
11 #include <linux/bitops.h>
12 #include <linux/init.h>
13 #include <linux/slab.h>
14 #include <linux/uaccess.h>
15 #include <linux/atomic.h>
16 
17 
18 extern int atm_init_aal5(struct atm_vcc *vcc); /* "raw" AAL5 transport */
19 
20 
21 #define PRIV(dev) ((struct atmtcp_dev_data *) ((dev)->dev_data))
22 
23 
24 struct atmtcp_dev_data {
25 	struct atm_vcc *vcc;	/* control VCC; NULL if detached */
26 	int persist;		/* non-zero if persistent */
27 };
28 
29 
30 #define DEV_LABEL    "atmtcp"
31 
32 #define MAX_VPI_BITS  8	/* simplifies life */
33 #define MAX_VCI_BITS 16
34 
35 
36 /*
37  * Hairy code ahead: the control VCC may be closed while we're still
38  * waiting for an answer, so we need to re-validate out_vcc every once
39  * in a while.
40  */
41 
42 
43 static int atmtcp_send_control(struct atm_vcc *vcc,int type,
44     const struct atmtcp_control *msg,int flag)
45 {
46 	DECLARE_WAITQUEUE(wait,current);
47 	struct atm_vcc *out_vcc;
48 	struct sk_buff *skb;
49 	struct atmtcp_control *new_msg;
50 	int old_test;
51 	int error = 0;
52 
53 	out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
54 	if (!out_vcc) return -EUNATCH;
55 	skb = alloc_skb(sizeof(*msg),GFP_KERNEL);
56 	if (!skb) return -ENOMEM;
57 	mb();
58 	out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
59 	if (!out_vcc) {
60 		dev_kfree_skb(skb);
61 		return -EUNATCH;
62 	}
63 	atm_force_charge(out_vcc,skb->truesize);
64 	new_msg = skb_put(skb, sizeof(*new_msg));
65 	*new_msg = *msg;
66 	new_msg->hdr.length = ATMTCP_HDR_MAGIC;
67 	new_msg->type = type;
68 	memset(&new_msg->vcc,0,sizeof(atm_kptr_t));
69 	*(struct atm_vcc **) &new_msg->vcc = vcc;
70 	old_test = test_bit(flag,&vcc->flags);
71 	out_vcc->push(out_vcc,skb);
72 	add_wait_queue(sk_sleep(sk_atm(vcc)), &wait);
73 	while (test_bit(flag,&vcc->flags) == old_test) {
74 		mb();
75 		out_vcc = PRIV(vcc->dev) ? PRIV(vcc->dev)->vcc : NULL;
76 		if (!out_vcc) {
77 			error = -EUNATCH;
78 			break;
79 		}
80 		set_current_state(TASK_UNINTERRUPTIBLE);
81 		schedule();
82 	}
83 	set_current_state(TASK_RUNNING);
84 	remove_wait_queue(sk_sleep(sk_atm(vcc)), &wait);
85 	return error;
86 }
87 
88 
89 static int atmtcp_recv_control(const struct atmtcp_control *msg)
90 {
91 	struct atm_vcc *vcc = *(struct atm_vcc **) &msg->vcc;
92 
93 	vcc->vpi = msg->addr.sap_addr.vpi;
94 	vcc->vci = msg->addr.sap_addr.vci;
95 	vcc->qos = msg->qos;
96 	sk_atm(vcc)->sk_err = -msg->result;
97 	switch (msg->type) {
98 	    case ATMTCP_CTRL_OPEN:
99 		change_bit(ATM_VF_READY,&vcc->flags);
100 		break;
101 	    case ATMTCP_CTRL_CLOSE:
102 		change_bit(ATM_VF_ADDR,&vcc->flags);
103 		break;
104 	    default:
105 		printk(KERN_ERR "atmtcp_recv_control: unknown type %d\n",
106 		    msg->type);
107 		return -EINVAL;
108 	}
109 	wake_up(sk_sleep(sk_atm(vcc)));
110 	return 0;
111 }
112 
113 
114 static void atmtcp_v_dev_close(struct atm_dev *dev)
115 {
116 	/* Nothing.... Isn't this simple :-)  -- REW */
117 }
118 
119 
120 static int atmtcp_v_open(struct atm_vcc *vcc)
121 {
122 	struct atmtcp_control msg;
123 	int error;
124 	short vpi = vcc->vpi;
125 	int vci = vcc->vci;
126 
127 	memset(&msg,0,sizeof(msg));
128 	msg.addr.sap_family = AF_ATMPVC;
129 	msg.hdr.vpi = htons(vpi);
130 	msg.addr.sap_addr.vpi = vpi;
131 	msg.hdr.vci = htons(vci);
132 	msg.addr.sap_addr.vci = vci;
133 	if (vpi == ATM_VPI_UNSPEC || vci == ATM_VCI_UNSPEC) return 0;
134 	msg.type = ATMTCP_CTRL_OPEN;
135 	msg.qos = vcc->qos;
136 	set_bit(ATM_VF_ADDR,&vcc->flags);
137 	clear_bit(ATM_VF_READY,&vcc->flags); /* just in case ... */
138 	error = atmtcp_send_control(vcc,ATMTCP_CTRL_OPEN,&msg,ATM_VF_READY);
139 	if (error) return error;
140 	return -sk_atm(vcc)->sk_err;
141 }
142 
143 
144 static void atmtcp_v_close(struct atm_vcc *vcc)
145 {
146 	struct atmtcp_control msg;
147 
148 	memset(&msg,0,sizeof(msg));
149 	msg.addr.sap_family = AF_ATMPVC;
150 	msg.addr.sap_addr.vpi = vcc->vpi;
151 	msg.addr.sap_addr.vci = vcc->vci;
152 	clear_bit(ATM_VF_READY,&vcc->flags);
153 	(void) atmtcp_send_control(vcc,ATMTCP_CTRL_CLOSE,&msg,ATM_VF_ADDR);
154 }
155 
156 
157 static int atmtcp_v_ioctl(struct atm_dev *dev,unsigned int cmd,void __user *arg)
158 {
159 	struct atm_cirange ci;
160 	struct atm_vcc *vcc;
161 	struct sock *s;
162 	int i;
163 
164 	if (cmd != ATM_SETCIRANGE) return -ENOIOCTLCMD;
165 	if (copy_from_user(&ci, arg,sizeof(ci))) return -EFAULT;
166 	if (ci.vpi_bits == ATM_CI_MAX) ci.vpi_bits = MAX_VPI_BITS;
167 	if (ci.vci_bits == ATM_CI_MAX) ci.vci_bits = MAX_VCI_BITS;
168 	if (ci.vpi_bits > MAX_VPI_BITS || ci.vpi_bits < 0 ||
169 	    ci.vci_bits > MAX_VCI_BITS || ci.vci_bits < 0) return -EINVAL;
170 	read_lock(&vcc_sklist_lock);
171 	for(i = 0; i < VCC_HTABLE_SIZE; ++i) {
172 		struct hlist_head *head = &vcc_hash[i];
173 
174 		sk_for_each(s, head) {
175 			vcc = atm_sk(s);
176 			if (vcc->dev != dev)
177 				continue;
178 			if ((vcc->vpi >> ci.vpi_bits) ||
179 			    (vcc->vci >> ci.vci_bits)) {
180 				read_unlock(&vcc_sklist_lock);
181 				return -EBUSY;
182 			}
183 		}
184 	}
185 	read_unlock(&vcc_sklist_lock);
186 	dev->ci_range = ci;
187 	return 0;
188 }
189 
190 
191 static int atmtcp_v_send(struct atm_vcc *vcc,struct sk_buff *skb)
192 {
193 	struct atmtcp_dev_data *dev_data;
194 	struct atm_vcc *out_vcc=NULL; /* Initializer quietens GCC warning */
195 	struct sk_buff *new_skb;
196 	struct atmtcp_hdr *hdr;
197 	int size;
198 
199 	if (vcc->qos.txtp.traffic_class == ATM_NONE) {
200 		if (vcc->pop) vcc->pop(vcc,skb);
201 		else dev_kfree_skb(skb);
202 		return -EINVAL;
203 	}
204 	dev_data = PRIV(vcc->dev);
205 	if (dev_data) out_vcc = dev_data->vcc;
206 	if (!dev_data || !out_vcc) {
207 		if (vcc->pop) vcc->pop(vcc,skb);
208 		else dev_kfree_skb(skb);
209 		if (dev_data) return 0;
210 		atomic_inc(&vcc->stats->tx_err);
211 		return -ENOLINK;
212 	}
213 	size = skb->len+sizeof(struct atmtcp_hdr);
214 	new_skb = atm_alloc_charge(out_vcc,size,GFP_ATOMIC);
215 	if (!new_skb) {
216 		if (vcc->pop) vcc->pop(vcc,skb);
217 		else dev_kfree_skb(skb);
218 		atomic_inc(&vcc->stats->tx_err);
219 		return -ENOBUFS;
220 	}
221 	hdr = skb_put(new_skb, sizeof(struct atmtcp_hdr));
222 	hdr->vpi = htons(vcc->vpi);
223 	hdr->vci = htons(vcc->vci);
224 	hdr->length = htonl(skb->len);
225 	skb_copy_from_linear_data(skb, skb_put(new_skb, skb->len), skb->len);
226 	if (vcc->pop) vcc->pop(vcc,skb);
227 	else dev_kfree_skb(skb);
228 	out_vcc->push(out_vcc,new_skb);
229 	atomic_inc(&vcc->stats->tx);
230 	atomic_inc(&out_vcc->stats->rx);
231 	return 0;
232 }
233 
234 
235 static int atmtcp_v_proc(struct atm_dev *dev,loff_t *pos,char *page)
236 {
237 	struct atmtcp_dev_data *dev_data = PRIV(dev);
238 
239 	if (*pos) return 0;
240 	if (!dev_data->persist) return sprintf(page,"ephemeral\n");
241 	return sprintf(page,"persistent, %sconnected\n",
242 	    dev_data->vcc ? "" : "dis");
243 }
244 
245 
246 static void atmtcp_c_close(struct atm_vcc *vcc)
247 {
248 	struct atm_dev *atmtcp_dev;
249 	struct atmtcp_dev_data *dev_data;
250 
251 	atmtcp_dev = (struct atm_dev *) vcc->dev_data;
252 	dev_data = PRIV(atmtcp_dev);
253 	dev_data->vcc = NULL;
254 	if (dev_data->persist) return;
255 	atmtcp_dev->dev_data = NULL;
256 	kfree(dev_data);
257 	atm_dev_deregister(atmtcp_dev);
258 	vcc->dev_data = NULL;
259 	module_put(THIS_MODULE);
260 }
261 
262 
263 static struct atm_vcc *find_vcc(struct atm_dev *dev, short vpi, int vci)
264 {
265         struct hlist_head *head;
266         struct atm_vcc *vcc;
267         struct sock *s;
268 
269         head = &vcc_hash[vci & (VCC_HTABLE_SIZE -1)];
270 
271 	sk_for_each(s, head) {
272                 vcc = atm_sk(s);
273                 if (vcc->dev == dev &&
274                     vcc->vci == vci && vcc->vpi == vpi &&
275                     vcc->qos.rxtp.traffic_class != ATM_NONE) {
276                                 return vcc;
277                 }
278         }
279         return NULL;
280 }
281 
282 
283 static int atmtcp_c_send(struct atm_vcc *vcc,struct sk_buff *skb)
284 {
285 	struct atm_dev *dev;
286 	struct atmtcp_hdr *hdr;
287 	struct atm_vcc *out_vcc;
288 	struct sk_buff *new_skb;
289 	int result = 0;
290 
291 	if (!skb->len) return 0;
292 	dev = vcc->dev_data;
293 	hdr = (struct atmtcp_hdr *) skb->data;
294 	if (hdr->length == ATMTCP_HDR_MAGIC) {
295 		result = atmtcp_recv_control(
296 		    (struct atmtcp_control *) skb->data);
297 		goto done;
298 	}
299 	read_lock(&vcc_sklist_lock);
300 	out_vcc = find_vcc(dev, ntohs(hdr->vpi), ntohs(hdr->vci));
301 	read_unlock(&vcc_sklist_lock);
302 	if (!out_vcc) {
303 		result = -EUNATCH;
304 		atomic_inc(&vcc->stats->tx_err);
305 		goto done;
306 	}
307 	skb_pull(skb,sizeof(struct atmtcp_hdr));
308 	new_skb = atm_alloc_charge(out_vcc,skb->len,GFP_KERNEL);
309 	if (!new_skb) {
310 		result = -ENOBUFS;
311 		goto done;
312 	}
313 	__net_timestamp(new_skb);
314 	skb_copy_from_linear_data(skb, skb_put(new_skb, skb->len), skb->len);
315 	out_vcc->push(out_vcc,new_skb);
316 	atomic_inc(&vcc->stats->tx);
317 	atomic_inc(&out_vcc->stats->rx);
318 done:
319 	if (vcc->pop) vcc->pop(vcc,skb);
320 	else dev_kfree_skb(skb);
321 	return result;
322 }
323 
324 
325 /*
326  * Device operations for the virtual ATM devices created by ATMTCP.
327  */
328 
329 
330 static struct atmdev_ops atmtcp_v_dev_ops = {
331 	.dev_close	= atmtcp_v_dev_close,
332 	.open		= atmtcp_v_open,
333 	.close		= atmtcp_v_close,
334 	.ioctl		= atmtcp_v_ioctl,
335 	.send		= atmtcp_v_send,
336 	.proc_read	= atmtcp_v_proc,
337 	.owner		= THIS_MODULE
338 };
339 
340 
341 /*
342  * Device operations for the ATMTCP control device.
343  */
344 
345 
346 static const struct atmdev_ops atmtcp_c_dev_ops = {
347 	.close		= atmtcp_c_close,
348 	.send		= atmtcp_c_send
349 };
350 
351 
352 static struct atm_dev atmtcp_control_dev = {
353 	.ops		= &atmtcp_c_dev_ops,
354 	.type		= "atmtcp",
355 	.number		= 999,
356 	.lock		= __SPIN_LOCK_UNLOCKED(atmtcp_control_dev.lock)
357 };
358 
359 
360 static int atmtcp_create(int itf,int persist,struct atm_dev **result)
361 {
362 	struct atmtcp_dev_data *dev_data;
363 	struct atm_dev *dev;
364 
365 	dev_data = kmalloc(sizeof(*dev_data),GFP_KERNEL);
366 	if (!dev_data)
367 		return -ENOMEM;
368 
369 	dev = atm_dev_register(DEV_LABEL,NULL,&atmtcp_v_dev_ops,itf,NULL);
370 	if (!dev) {
371 		kfree(dev_data);
372 		return itf == -1 ? -ENOMEM : -EBUSY;
373 	}
374 	dev->ci_range.vpi_bits = MAX_VPI_BITS;
375 	dev->ci_range.vci_bits = MAX_VCI_BITS;
376 	dev->dev_data = dev_data;
377 	PRIV(dev)->vcc = NULL;
378 	PRIV(dev)->persist = persist;
379 	if (result) *result = dev;
380 	return 0;
381 }
382 
383 
384 static int atmtcp_attach(struct atm_vcc *vcc,int itf)
385 {
386 	struct atm_dev *dev;
387 
388 	dev = NULL;
389 	if (itf != -1) dev = atm_dev_lookup(itf);
390 	if (dev) {
391 		if (dev->ops != &atmtcp_v_dev_ops) {
392 			atm_dev_put(dev);
393 			return -EMEDIUMTYPE;
394 		}
395 		if (PRIV(dev)->vcc) {
396 			atm_dev_put(dev);
397 			return -EBUSY;
398 		}
399 	}
400 	else {
401 		int error;
402 
403 		error = atmtcp_create(itf,0,&dev);
404 		if (error) return error;
405 	}
406 	PRIV(dev)->vcc = vcc;
407 	vcc->dev = &atmtcp_control_dev;
408 	vcc_insert_socket(sk_atm(vcc));
409 	set_bit(ATM_VF_META,&vcc->flags);
410 	set_bit(ATM_VF_READY,&vcc->flags);
411 	vcc->dev_data = dev;
412 	(void) atm_init_aal5(vcc); /* @@@ losing AAL in transit ... */
413 	vcc->stats = &atmtcp_control_dev.stats.aal5;
414 	return dev->number;
415 }
416 
417 
418 static int atmtcp_create_persistent(int itf)
419 {
420 	return atmtcp_create(itf,1,NULL);
421 }
422 
423 
424 static int atmtcp_remove_persistent(int itf)
425 {
426 	struct atm_dev *dev;
427 	struct atmtcp_dev_data *dev_data;
428 
429 	dev = atm_dev_lookup(itf);
430 	if (!dev) return -ENODEV;
431 	if (dev->ops != &atmtcp_v_dev_ops) {
432 		atm_dev_put(dev);
433 		return -EMEDIUMTYPE;
434 	}
435 	dev_data = PRIV(dev);
436 	if (!dev_data->persist) {
437 		atm_dev_put(dev);
438 		return 0;
439 	}
440 	dev_data->persist = 0;
441 	if (PRIV(dev)->vcc) {
442 		atm_dev_put(dev);
443 		return 0;
444 	}
445 	kfree(dev_data);
446 	atm_dev_put(dev);
447 	atm_dev_deregister(dev);
448 	return 0;
449 }
450 
451 static int atmtcp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
452 {
453 	int err = 0;
454 	struct atm_vcc *vcc = ATM_SD(sock);
455 
456 	if (cmd != SIOCSIFATMTCP && cmd != ATMTCP_CREATE && cmd != ATMTCP_REMOVE)
457 		return -ENOIOCTLCMD;
458 
459 	if (!capable(CAP_NET_ADMIN))
460 		return -EPERM;
461 
462 	switch (cmd) {
463 		case SIOCSIFATMTCP:
464 			err = atmtcp_attach(vcc, (int) arg);
465 			if (err >= 0) {
466 				sock->state = SS_CONNECTED;
467 				__module_get(THIS_MODULE);
468 			}
469 			break;
470 		case ATMTCP_CREATE:
471 			err = atmtcp_create_persistent((int) arg);
472 			break;
473 		case ATMTCP_REMOVE:
474 			err = atmtcp_remove_persistent((int) arg);
475 			break;
476 	}
477 	return err;
478 }
479 
480 static struct atm_ioctl atmtcp_ioctl_ops = {
481 	.owner 	= THIS_MODULE,
482 	.ioctl	= atmtcp_ioctl,
483 };
484 
485 static __init int atmtcp_init(void)
486 {
487 	register_atm_ioctl(&atmtcp_ioctl_ops);
488 	return 0;
489 }
490 
491 
492 static void __exit atmtcp_exit(void)
493 {
494 	deregister_atm_ioctl(&atmtcp_ioctl_ops);
495 }
496 
497 MODULE_LICENSE("GPL");
498 module_init(atmtcp_init);
499 module_exit(atmtcp_exit);
500