atmtcp.c

  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
 18extern 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
 24struct 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
 43static 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
 89static 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
114static void atmtcp_v_dev_close(struct atm_dev *dev)
115{
116	/* Nothing.... Isn't this simple :-)  -- REW */
117}
118
119
120static 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
144static 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
157static 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
191static 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
235static 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
246static 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
263static 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
282static int atmtcp_c_pre_send(struct atm_vcc *vcc, struct sk_buff *skb)
283{
284	struct atmtcp_hdr *hdr;
285
286	if (skb->len < sizeof(struct atmtcp_hdr))
287		return -EINVAL;
288
289	hdr = (struct atmtcp_hdr *)skb->data;
290	if (hdr->length == ATMTCP_HDR_MAGIC)
291		return -EINVAL;
292
293	return 0;
294}
295
296static int atmtcp_c_send(struct atm_vcc *vcc,struct sk_buff *skb)
297{
298	struct atm_dev *dev;
299	struct atmtcp_hdr *hdr;
300	struct atm_vcc *out_vcc;
301	struct sk_buff *new_skb;
302	int result = 0;
303
304	dev = vcc->dev_data;
305	hdr = (struct atmtcp_hdr *) skb->data;
306	if (hdr->length == ATMTCP_HDR_MAGIC) {
307		result = atmtcp_recv_control(
308		    (struct atmtcp_control *) skb->data);
309		goto done;
310	}
311	read_lock(&vcc_sklist_lock);
312	out_vcc = find_vcc(dev, ntohs(hdr->vpi), ntohs(hdr->vci));
313	read_unlock(&vcc_sklist_lock);
314	if (!out_vcc) {
315		result = -EUNATCH;
316		atomic_inc(&vcc->stats->tx_err);
317		goto done;
318	}
319	skb_pull(skb,sizeof(struct atmtcp_hdr));
320	new_skb = atm_alloc_charge(out_vcc,skb->len,GFP_KERNEL);
321	if (!new_skb) {
322		result = -ENOBUFS;
323		goto done;
324	}
325	__net_timestamp(new_skb);
326	skb_copy_from_linear_data(skb, skb_put(new_skb, skb->len), skb->len);
327	out_vcc->push(out_vcc,new_skb);
328	atomic_inc(&vcc->stats->tx);
329	atomic_inc(&out_vcc->stats->rx);
330done:
331	if (vcc->pop) vcc->pop(vcc,skb);
332	else dev_kfree_skb(skb);
333	return result;
334}
335
336
337/*
338 * Device operations for the virtual ATM devices created by ATMTCP.
339 */
340
341
342static const struct atmdev_ops atmtcp_v_dev_ops = {
343	.dev_close	= atmtcp_v_dev_close,
344	.open		= atmtcp_v_open,
345	.close		= atmtcp_v_close,
346	.ioctl		= atmtcp_v_ioctl,
347	.send		= atmtcp_v_send,
348	.proc_read	= atmtcp_v_proc,
349	.owner		= THIS_MODULE
350};
351
352
353/*
354 * Device operations for the ATMTCP control device.
355 */
356
357
358static const struct atmdev_ops atmtcp_c_dev_ops = {
359	.close		= atmtcp_c_close,
360	.pre_send	= atmtcp_c_pre_send,
361	.send		= atmtcp_c_send
362};
363
364
365static struct atm_dev atmtcp_control_dev = {
366	.ops		= &atmtcp_c_dev_ops,
367	.type		= "atmtcp",
368	.number		= 999,
369	.lock		= __SPIN_LOCK_UNLOCKED(atmtcp_control_dev.lock)
370};
371
372
373static int atmtcp_create(int itf,int persist,struct atm_dev **result)
374{
375	struct atmtcp_dev_data *dev_data;
376	struct atm_dev *dev;
377
378	dev_data = kmalloc(sizeof(*dev_data),GFP_KERNEL);
379	if (!dev_data)
380		return -ENOMEM;
381
382	dev = atm_dev_register(DEV_LABEL,NULL,&atmtcp_v_dev_ops,itf,NULL);
383	if (!dev) {
384		kfree(dev_data);
385		return itf == -1 ? -ENOMEM : -EBUSY;
386	}
387	dev->ci_range.vpi_bits = MAX_VPI_BITS;
388	dev->ci_range.vci_bits = MAX_VCI_BITS;
389	dev->dev_data = dev_data;
390	PRIV(dev)->vcc = NULL;
391	PRIV(dev)->persist = persist;
392	if (result) *result = dev;
393	return 0;
394}
395
396
397static int atmtcp_attach(struct atm_vcc *vcc,int itf)
398{
399	struct atm_dev *dev;
400
401	dev = NULL;
402	if (itf != -1) dev = atm_dev_lookup(itf);
403	if (dev) {
404		if (dev->ops != &atmtcp_v_dev_ops) {
405			atm_dev_put(dev);
406			return -EMEDIUMTYPE;
407		}
408		if (PRIV(dev)->vcc) {
409			atm_dev_put(dev);
410			return -EBUSY;
411		}
412	}
413	else {
414		int error;
415
416		error = atmtcp_create(itf,0,&dev);
417		if (error) return error;
418	}
419	PRIV(dev)->vcc = vcc;
420	vcc->dev = &atmtcp_control_dev;
421	vcc_insert_socket(sk_atm(vcc));
422	set_bit(ATM_VF_META,&vcc->flags);
423	set_bit(ATM_VF_READY,&vcc->flags);
424	vcc->dev_data = dev;
425	(void) atm_init_aal5(vcc); /* @@@ losing AAL in transit ... */
426	vcc->stats = &atmtcp_control_dev.stats.aal5;
427	return dev->number;
428}
429
430
431static int atmtcp_create_persistent(int itf)
432{
433	return atmtcp_create(itf,1,NULL);
434}
435
436
437static int atmtcp_remove_persistent(int itf)
438{
439	struct atm_dev *dev;
440	struct atmtcp_dev_data *dev_data;
441
442	dev = atm_dev_lookup(itf);
443	if (!dev) return -ENODEV;
444	if (dev->ops != &atmtcp_v_dev_ops) {
445		atm_dev_put(dev);
446		return -EMEDIUMTYPE;
447	}
448	dev_data = PRIV(dev);
449	if (!dev_data->persist) {
450		atm_dev_put(dev);
451		return 0;
452	}
453	dev_data->persist = 0;
454	if (PRIV(dev)->vcc) {
455		atm_dev_put(dev);
456		return 0;
457	}
458	kfree(dev_data);
459	atm_dev_put(dev);
460	atm_dev_deregister(dev);
461	return 0;
462}
463
464static int atmtcp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
465{
466	int err = 0;
467	struct atm_vcc *vcc = ATM_SD(sock);
468
469	if (cmd != SIOCSIFATMTCP && cmd != ATMTCP_CREATE && cmd != ATMTCP_REMOVE)
470		return -ENOIOCTLCMD;
471
472	if (!capable(CAP_NET_ADMIN))
473		return -EPERM;
474
475	switch (cmd) {
476		case SIOCSIFATMTCP:
477			err = atmtcp_attach(vcc, (int) arg);
478			if (err >= 0) {
479				sock->state = SS_CONNECTED;
480				__module_get(THIS_MODULE);
481			}
482			break;
483		case ATMTCP_CREATE:
484			err = atmtcp_create_persistent((int) arg);
485			break;
486		case ATMTCP_REMOVE:
487			err = atmtcp_remove_persistent((int) arg);
488			break;
489	}
490	return err;
491}
492
493static struct atm_ioctl atmtcp_ioctl_ops = {
494	.owner 	= THIS_MODULE,
495	.ioctl	= atmtcp_ioctl,
496};
497
498static __init int atmtcp_init(void)
499{
500	register_atm_ioctl(&atmtcp_ioctl_ops);
501	return 0;
502}
503
504
505static void __exit atmtcp_exit(void)
506{
507	deregister_atm_ioctl(&atmtcp_ioctl_ops);
508}
509
510MODULE_DESCRIPTION("ATM over TCP");
511MODULE_LICENSE("GPL");
512module_init(atmtcp_init);
513module_exit(atmtcp_exit);