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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Generic PPP layer for Linux.
4  *
5  * Copyright 1999-2002 Paul Mackerras.
6  *
7  * The generic PPP layer handles the PPP network interfaces, the
8  * /dev/ppp device, packet and VJ compression, and multilink.
9  * It talks to PPP `channels' via the interface defined in
10  * include/linux/ppp_channel.h.  Channels provide the basic means for
11  * sending and receiving PPP frames on some kind of communications
12  * channel.
13  *
14  * Part of the code in this driver was inspired by the old async-only
15  * PPP driver, written by Michael Callahan and Al Longyear, and
16  * subsequently hacked by Paul Mackerras.
17  *
18  * ==FILEVERSION 20041108==
19  */
20 
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/sched/signal.h>
24 #include <linux/kmod.h>
25 #include <linux/init.h>
26 #include <linux/list.h>
27 #include <linux/idr.h>
28 #include <linux/netdevice.h>
29 #include <linux/poll.h>
30 #include <linux/ppp_defs.h>
31 #include <linux/filter.h>
32 #include <linux/ppp-ioctl.h>
33 #include <linux/ppp_channel.h>
34 #include <linux/ppp-comp.h>
35 #include <linux/skbuff.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/if_arp.h>
38 #include <linux/ip.h>
39 #include <linux/tcp.h>
40 #include <linux/spinlock.h>
41 #include <linux/rwsem.h>
42 #include <linux/stddef.h>
43 #include <linux/device.h>
44 #include <linux/mutex.h>
45 #include <linux/slab.h>
46 #include <linux/file.h>
47 #include <asm/unaligned.h>
48 #include <net/slhc_vj.h>
49 #include <linux/atomic.h>
50 #include <linux/refcount.h>
51 
52 #include <linux/nsproxy.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55 
56 #define PPP_VERSION	"2.4.2"
57 
58 /*
59  * Network protocols we support.
60  */
61 #define NP_IP	0		/* Internet Protocol V4 */
62 #define NP_IPV6	1		/* Internet Protocol V6 */
63 #define NP_IPX	2		/* IPX protocol */
64 #define NP_AT	3		/* Appletalk protocol */
65 #define NP_MPLS_UC 4		/* MPLS unicast */
66 #define NP_MPLS_MC 5		/* MPLS multicast */
67 #define NUM_NP	6		/* Number of NPs. */
68 
69 #define MPHDRLEN	6	/* multilink protocol header length */
70 #define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
71 
72 #define PPP_PROTO_LEN	2
73 
74 /*
75  * An instance of /dev/ppp can be associated with either a ppp
76  * interface unit or a ppp channel.  In both cases, file->private_data
77  * points to one of these.
78  */
79 struct ppp_file {
80 	enum {
81 		INTERFACE=1, CHANNEL
82 	}		kind;
83 	struct sk_buff_head xq;		/* pppd transmit queue */
84 	struct sk_buff_head rq;		/* receive queue for pppd */
85 	wait_queue_head_t rwait;	/* for poll on reading /dev/ppp */
86 	refcount_t	refcnt;		/* # refs (incl /dev/ppp attached) */
87 	int		hdrlen;		/* space to leave for headers */
88 	int		index;		/* interface unit / channel number */
89 	int		dead;		/* unit/channel has been shut down */
90 };
91 
92 #define PF_TO_X(pf, X)		container_of(pf, X, file)
93 
94 #define PF_TO_PPP(pf)		PF_TO_X(pf, struct ppp)
95 #define PF_TO_CHANNEL(pf)	PF_TO_X(pf, struct channel)
96 
97 /*
98  * Data structure to hold primary network stats for which
99  * we want to use 64 bit storage.  Other network stats
100  * are stored in dev->stats of the ppp strucute.
101  */
102 struct ppp_link_stats {
103 	u64 rx_packets;
104 	u64 tx_packets;
105 	u64 rx_bytes;
106 	u64 tx_bytes;
107 };
108 
109 /*
110  * Data structure describing one ppp unit.
111  * A ppp unit corresponds to a ppp network interface device
112  * and represents a multilink bundle.
113  * It can have 0 or more ppp channels connected to it.
114  */
115 struct ppp {
116 	struct ppp_file	file;		/* stuff for read/write/poll 0 */
117 	struct file	*owner;		/* file that owns this unit 48 */
118 	struct list_head channels;	/* list of attached channels 4c */
119 	int		n_channels;	/* how many channels are attached 54 */
120 	spinlock_t	rlock;		/* lock for receive side 58 */
121 	spinlock_t	wlock;		/* lock for transmit side 5c */
122 	int __percpu	*xmit_recursion; /* xmit recursion detect */
123 	int		mru;		/* max receive unit 60 */
124 	unsigned int	flags;		/* control bits 64 */
125 	unsigned int	xstate;		/* transmit state bits 68 */
126 	unsigned int	rstate;		/* receive state bits 6c */
127 	int		debug;		/* debug flags 70 */
128 	struct slcompress *vj;		/* state for VJ header compression */
129 	enum NPmode	npmode[NUM_NP];	/* what to do with each net proto 78 */
130 	struct sk_buff	*xmit_pending;	/* a packet ready to go out 88 */
131 	struct compressor *xcomp;	/* transmit packet compressor 8c */
132 	void		*xc_state;	/* its internal state 90 */
133 	struct compressor *rcomp;	/* receive decompressor 94 */
134 	void		*rc_state;	/* its internal state 98 */
135 	unsigned long	last_xmit;	/* jiffies when last pkt sent 9c */
136 	unsigned long	last_recv;	/* jiffies when last pkt rcvd a0 */
137 	struct net_device *dev;		/* network interface device a4 */
138 	int		closing;	/* is device closing down? a8 */
139 #ifdef CONFIG_PPP_MULTILINK
140 	int		nxchan;		/* next channel to send something on */
141 	u32		nxseq;		/* next sequence number to send */
142 	int		mrru;		/* MP: max reconst. receive unit */
143 	u32		nextseq;	/* MP: seq no of next packet */
144 	u32		minseq;		/* MP: min of most recent seqnos */
145 	struct sk_buff_head mrq;	/* MP: receive reconstruction queue */
146 #endif /* CONFIG_PPP_MULTILINK */
147 #ifdef CONFIG_PPP_FILTER
148 	struct bpf_prog *pass_filter;	/* filter for packets to pass */
149 	struct bpf_prog *active_filter; /* filter for pkts to reset idle */
150 #endif /* CONFIG_PPP_FILTER */
151 	struct net	*ppp_net;	/* the net we belong to */
152 	struct ppp_link_stats stats64;	/* 64 bit network stats */
153 };
154 
155 /*
156  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
157  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
158  * SC_MUST_COMP
159  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
160  * Bits in xstate: SC_COMP_RUN
161  */
162 #define SC_FLAG_BITS	(SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
163 			 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
164 			 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
165 
166 /*
167  * Private data structure for each channel.
168  * This includes the data structure used for multilink.
169  */
170 struct channel {
171 	struct ppp_file	file;		/* stuff for read/write/poll */
172 	struct list_head list;		/* link in all/new_channels list */
173 	struct ppp_channel *chan;	/* public channel data structure */
174 	struct rw_semaphore chan_sem;	/* protects `chan' during chan ioctl */
175 	spinlock_t	downl;		/* protects `chan', file.xq dequeue */
176 	struct ppp	*ppp;		/* ppp unit we're connected to */
177 	struct net	*chan_net;	/* the net channel belongs to */
178 	struct list_head clist;		/* link in list of channels per unit */
179 	rwlock_t	upl;		/* protects `ppp' */
180 #ifdef CONFIG_PPP_MULTILINK
181 	u8		avail;		/* flag used in multilink stuff */
182 	u8		had_frag;	/* >= 1 fragments have been sent */
183 	u32		lastseq;	/* MP: last sequence # received */
184 	int		speed;		/* speed of the corresponding ppp channel*/
185 #endif /* CONFIG_PPP_MULTILINK */
186 };
187 
188 struct ppp_config {
189 	struct file *file;
190 	s32 unit;
191 	bool ifname_is_set;
192 };
193 
194 /*
195  * SMP locking issues:
196  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
197  * list and the ppp.n_channels field, you need to take both locks
198  * before you modify them.
199  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
200  * channel.downl.
201  */
202 
203 static DEFINE_MUTEX(ppp_mutex);
204 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
205 static atomic_t channel_count = ATOMIC_INIT(0);
206 
207 /* per-net private data for this module */
208 static unsigned int ppp_net_id __read_mostly;
209 struct ppp_net {
210 	/* units to ppp mapping */
211 	struct idr units_idr;
212 
213 	/*
214 	 * all_ppp_mutex protects the units_idr mapping.
215 	 * It also ensures that finding a ppp unit in the units_idr
216 	 * map and updating its file.refcnt field is atomic.
217 	 */
218 	struct mutex all_ppp_mutex;
219 
220 	/* channels */
221 	struct list_head all_channels;
222 	struct list_head new_channels;
223 	int last_channel_index;
224 
225 	/*
226 	 * all_channels_lock protects all_channels and
227 	 * last_channel_index, and the atomicity of find
228 	 * a channel and updating its file.refcnt field.
229 	 */
230 	spinlock_t all_channels_lock;
231 };
232 
233 /* Get the PPP protocol number from a skb */
234 #define PPP_PROTO(skb)	get_unaligned_be16((skb)->data)
235 
236 /* We limit the length of ppp->file.rq to this (arbitrary) value */
237 #define PPP_MAX_RQLEN	32
238 
239 /*
240  * Maximum number of multilink fragments queued up.
241  * This has to be large enough to cope with the maximum latency of
242  * the slowest channel relative to the others.  Strictly it should
243  * depend on the number of channels and their characteristics.
244  */
245 #define PPP_MP_MAX_QLEN	128
246 
247 /* Multilink header bits. */
248 #define B	0x80		/* this fragment begins a packet */
249 #define E	0x40		/* this fragment ends a packet */
250 
251 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
252 #define seq_before(a, b)	((s32)((a) - (b)) < 0)
253 #define seq_after(a, b)		((s32)((a) - (b)) > 0)
254 
255 /* Prototypes. */
256 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
257 			struct file *file, unsigned int cmd, unsigned long arg);
258 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
259 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
260 static void ppp_push(struct ppp *ppp);
261 static void ppp_channel_push(struct channel *pch);
262 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
263 			      struct channel *pch);
264 static void ppp_receive_error(struct ppp *ppp);
265 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
266 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
267 					    struct sk_buff *skb);
268 #ifdef CONFIG_PPP_MULTILINK
269 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
270 				struct channel *pch);
271 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
272 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
273 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
274 #endif /* CONFIG_PPP_MULTILINK */
275 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
276 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
277 static void ppp_ccp_closed(struct ppp *ppp);
278 static struct compressor *find_compressor(int type);
279 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
280 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
281 static void init_ppp_file(struct ppp_file *pf, int kind);
282 static void ppp_destroy_interface(struct ppp *ppp);
283 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
284 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
285 static int ppp_connect_channel(struct channel *pch, int unit);
286 static int ppp_disconnect_channel(struct channel *pch);
287 static void ppp_destroy_channel(struct channel *pch);
288 static int unit_get(struct idr *p, void *ptr, int min);
289 static int unit_set(struct idr *p, void *ptr, int n);
290 static void unit_put(struct idr *p, int n);
291 static void *unit_find(struct idr *p, int n);
292 static void ppp_setup(struct net_device *dev);
293 
294 static const struct net_device_ops ppp_netdev_ops;
295 
296 static struct class *ppp_class;
297 
298 /* per net-namespace data */
ppp_pernet(struct net * net)299 static inline struct ppp_net *ppp_pernet(struct net *net)
300 {
301 	return net_generic(net, ppp_net_id);
302 }
303 
304 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)305 static inline int proto_to_npindex(int proto)
306 {
307 	switch (proto) {
308 	case PPP_IP:
309 		return NP_IP;
310 	case PPP_IPV6:
311 		return NP_IPV6;
312 	case PPP_IPX:
313 		return NP_IPX;
314 	case PPP_AT:
315 		return NP_AT;
316 	case PPP_MPLS_UC:
317 		return NP_MPLS_UC;
318 	case PPP_MPLS_MC:
319 		return NP_MPLS_MC;
320 	}
321 	return -EINVAL;
322 }
323 
324 /* Translates an NP index into a PPP protocol number */
325 static const int npindex_to_proto[NUM_NP] = {
326 	PPP_IP,
327 	PPP_IPV6,
328 	PPP_IPX,
329 	PPP_AT,
330 	PPP_MPLS_UC,
331 	PPP_MPLS_MC,
332 };
333 
334 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)335 static inline int ethertype_to_npindex(int ethertype)
336 {
337 	switch (ethertype) {
338 	case ETH_P_IP:
339 		return NP_IP;
340 	case ETH_P_IPV6:
341 		return NP_IPV6;
342 	case ETH_P_IPX:
343 		return NP_IPX;
344 	case ETH_P_PPPTALK:
345 	case ETH_P_ATALK:
346 		return NP_AT;
347 	case ETH_P_MPLS_UC:
348 		return NP_MPLS_UC;
349 	case ETH_P_MPLS_MC:
350 		return NP_MPLS_MC;
351 	}
352 	return -1;
353 }
354 
355 /* Translates an NP index into an ethertype */
356 static const int npindex_to_ethertype[NUM_NP] = {
357 	ETH_P_IP,
358 	ETH_P_IPV6,
359 	ETH_P_IPX,
360 	ETH_P_PPPTALK,
361 	ETH_P_MPLS_UC,
362 	ETH_P_MPLS_MC,
363 };
364 
365 /*
366  * Locking shorthand.
367  */
368 #define ppp_xmit_lock(ppp)	spin_lock_bh(&(ppp)->wlock)
369 #define ppp_xmit_unlock(ppp)	spin_unlock_bh(&(ppp)->wlock)
370 #define ppp_recv_lock(ppp)	spin_lock_bh(&(ppp)->rlock)
371 #define ppp_recv_unlock(ppp)	spin_unlock_bh(&(ppp)->rlock)
372 #define ppp_lock(ppp)		do { ppp_xmit_lock(ppp); \
373 				     ppp_recv_lock(ppp); } while (0)
374 #define ppp_unlock(ppp)		do { ppp_recv_unlock(ppp); \
375 				     ppp_xmit_unlock(ppp); } while (0)
376 
377 /*
378  * /dev/ppp device routines.
379  * The /dev/ppp device is used by pppd to control the ppp unit.
380  * It supports the read, write, ioctl and poll functions.
381  * Open instances of /dev/ppp can be in one of three states:
382  * unattached, attached to a ppp unit, or attached to a ppp channel.
383  */
ppp_open(struct inode * inode,struct file * file)384 static int ppp_open(struct inode *inode, struct file *file)
385 {
386 	/*
387 	 * This could (should?) be enforced by the permissions on /dev/ppp.
388 	 */
389 	if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
390 		return -EPERM;
391 	return 0;
392 }
393 
ppp_release(struct inode * unused,struct file * file)394 static int ppp_release(struct inode *unused, struct file *file)
395 {
396 	struct ppp_file *pf = file->private_data;
397 	struct ppp *ppp;
398 
399 	if (pf) {
400 		file->private_data = NULL;
401 		if (pf->kind == INTERFACE) {
402 			ppp = PF_TO_PPP(pf);
403 			rtnl_lock();
404 			if (file == ppp->owner)
405 				unregister_netdevice(ppp->dev);
406 			rtnl_unlock();
407 		}
408 		if (refcount_dec_and_test(&pf->refcnt)) {
409 			switch (pf->kind) {
410 			case INTERFACE:
411 				ppp_destroy_interface(PF_TO_PPP(pf));
412 				break;
413 			case CHANNEL:
414 				ppp_destroy_channel(PF_TO_CHANNEL(pf));
415 				break;
416 			}
417 		}
418 	}
419 	return 0;
420 }
421 
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)422 static ssize_t ppp_read(struct file *file, char __user *buf,
423 			size_t count, loff_t *ppos)
424 {
425 	struct ppp_file *pf = file->private_data;
426 	DECLARE_WAITQUEUE(wait, current);
427 	ssize_t ret;
428 	struct sk_buff *skb = NULL;
429 	struct iovec iov;
430 	struct iov_iter to;
431 
432 	ret = count;
433 
434 	if (!pf)
435 		return -ENXIO;
436 	add_wait_queue(&pf->rwait, &wait);
437 	for (;;) {
438 		set_current_state(TASK_INTERRUPTIBLE);
439 		skb = skb_dequeue(&pf->rq);
440 		if (skb)
441 			break;
442 		ret = 0;
443 		if (pf->dead)
444 			break;
445 		if (pf->kind == INTERFACE) {
446 			/*
447 			 * Return 0 (EOF) on an interface that has no
448 			 * channels connected, unless it is looping
449 			 * network traffic (demand mode).
450 			 */
451 			struct ppp *ppp = PF_TO_PPP(pf);
452 
453 			ppp_recv_lock(ppp);
454 			if (ppp->n_channels == 0 &&
455 			    (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
456 				ppp_recv_unlock(ppp);
457 				break;
458 			}
459 			ppp_recv_unlock(ppp);
460 		}
461 		ret = -EAGAIN;
462 		if (file->f_flags & O_NONBLOCK)
463 			break;
464 		ret = -ERESTARTSYS;
465 		if (signal_pending(current))
466 			break;
467 		schedule();
468 	}
469 	set_current_state(TASK_RUNNING);
470 	remove_wait_queue(&pf->rwait, &wait);
471 
472 	if (!skb)
473 		goto out;
474 
475 	ret = -EOVERFLOW;
476 	if (skb->len > count)
477 		goto outf;
478 	ret = -EFAULT;
479 	iov.iov_base = buf;
480 	iov.iov_len = count;
481 	iov_iter_init(&to, READ, &iov, 1, count);
482 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
483 		goto outf;
484 	ret = skb->len;
485 
486  outf:
487 	kfree_skb(skb);
488  out:
489 	return ret;
490 }
491 
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)492 static ssize_t ppp_write(struct file *file, const char __user *buf,
493 			 size_t count, loff_t *ppos)
494 {
495 	struct ppp_file *pf = file->private_data;
496 	struct sk_buff *skb;
497 	ssize_t ret;
498 
499 	if (!pf)
500 		return -ENXIO;
501 	/* All PPP packets should start with the 2-byte protocol */
502 	if (count < PPP_PROTO_LEN)
503 		return -EINVAL;
504 	ret = -ENOMEM;
505 	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
506 	if (!skb)
507 		goto out;
508 	skb_reserve(skb, pf->hdrlen);
509 	ret = -EFAULT;
510 	if (copy_from_user(skb_put(skb, count), buf, count)) {
511 		kfree_skb(skb);
512 		goto out;
513 	}
514 
515 	switch (pf->kind) {
516 	case INTERFACE:
517 		ppp_xmit_process(PF_TO_PPP(pf), skb);
518 		break;
519 	case CHANNEL:
520 		skb_queue_tail(&pf->xq, skb);
521 		ppp_channel_push(PF_TO_CHANNEL(pf));
522 		break;
523 	}
524 
525 	ret = count;
526 
527  out:
528 	return ret;
529 }
530 
531 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)532 static __poll_t ppp_poll(struct file *file, poll_table *wait)
533 {
534 	struct ppp_file *pf = file->private_data;
535 	__poll_t mask;
536 
537 	if (!pf)
538 		return 0;
539 	poll_wait(file, &pf->rwait, wait);
540 	mask = EPOLLOUT | EPOLLWRNORM;
541 	if (skb_peek(&pf->rq))
542 		mask |= EPOLLIN | EPOLLRDNORM;
543 	if (pf->dead)
544 		mask |= EPOLLHUP;
545 	else if (pf->kind == INTERFACE) {
546 		/* see comment in ppp_read */
547 		struct ppp *ppp = PF_TO_PPP(pf);
548 
549 		ppp_recv_lock(ppp);
550 		if (ppp->n_channels == 0 &&
551 		    (ppp->flags & SC_LOOP_TRAFFIC) == 0)
552 			mask |= EPOLLIN | EPOLLRDNORM;
553 		ppp_recv_unlock(ppp);
554 	}
555 
556 	return mask;
557 }
558 
559 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)560 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
561 {
562 	struct sock_fprog_kern fprog;
563 	struct bpf_prog *res = NULL;
564 	int err;
565 
566 	if (!uprog->len)
567 		return NULL;
568 
569 	/* uprog->len is unsigned short, so no overflow here */
570 	fprog.len = uprog->len;
571 	fprog.filter = memdup_user(uprog->filter,
572 				   uprog->len * sizeof(struct sock_filter));
573 	if (IS_ERR(fprog.filter))
574 		return ERR_CAST(fprog.filter);
575 
576 	err = bpf_prog_create(&res, &fprog);
577 	kfree(fprog.filter);
578 
579 	return err ? ERR_PTR(err) : res;
580 }
581 
ppp_get_filter(struct sock_fprog __user * p)582 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
583 {
584 	struct sock_fprog uprog;
585 
586 	if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
587 		return ERR_PTR(-EFAULT);
588 	return get_filter(&uprog);
589 }
590 
591 #ifdef CONFIG_COMPAT
592 struct sock_fprog32 {
593 	unsigned short len;
594 	compat_caddr_t filter;
595 };
596 
597 #define PPPIOCSPASS32		_IOW('t', 71, struct sock_fprog32)
598 #define PPPIOCSACTIVE32		_IOW('t', 70, struct sock_fprog32)
599 
compat_ppp_get_filter(struct sock_fprog32 __user * p)600 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
601 {
602 	struct sock_fprog32 uprog32;
603 	struct sock_fprog uprog;
604 
605 	if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
606 		return ERR_PTR(-EFAULT);
607 	uprog.len = uprog32.len;
608 	uprog.filter = compat_ptr(uprog32.filter);
609 	return get_filter(&uprog);
610 }
611 #endif
612 #endif
613 
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)614 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
615 {
616 	struct ppp_file *pf;
617 	struct ppp *ppp;
618 	int err = -EFAULT, val, val2, i;
619 	struct ppp_idle32 idle32;
620 	struct ppp_idle64 idle64;
621 	struct npioctl npi;
622 	int unit, cflags;
623 	struct slcompress *vj;
624 	void __user *argp = (void __user *)arg;
625 	int __user *p = argp;
626 
627 	mutex_lock(&ppp_mutex);
628 
629 	pf = file->private_data;
630 	if (!pf) {
631 		err = ppp_unattached_ioctl(current->nsproxy->net_ns,
632 					   pf, file, cmd, arg);
633 		goto out;
634 	}
635 
636 	if (cmd == PPPIOCDETACH) {
637 		/*
638 		 * PPPIOCDETACH is no longer supported as it was heavily broken,
639 		 * and is only known to have been used by pppd older than
640 		 * ppp-2.4.2 (released November 2003).
641 		 */
642 		pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
643 			     current->comm, current->pid);
644 		err = -EINVAL;
645 		goto out;
646 	}
647 
648 	if (pf->kind == CHANNEL) {
649 		struct channel *pch;
650 		struct ppp_channel *chan;
651 
652 		pch = PF_TO_CHANNEL(pf);
653 
654 		switch (cmd) {
655 		case PPPIOCCONNECT:
656 			if (get_user(unit, p))
657 				break;
658 			err = ppp_connect_channel(pch, unit);
659 			break;
660 
661 		case PPPIOCDISCONN:
662 			err = ppp_disconnect_channel(pch);
663 			break;
664 
665 		default:
666 			down_read(&pch->chan_sem);
667 			chan = pch->chan;
668 			err = -ENOTTY;
669 			if (chan && chan->ops->ioctl)
670 				err = chan->ops->ioctl(chan, cmd, arg);
671 			up_read(&pch->chan_sem);
672 		}
673 		goto out;
674 	}
675 
676 	if (pf->kind != INTERFACE) {
677 		/* can't happen */
678 		pr_err("PPP: not interface or channel??\n");
679 		err = -EINVAL;
680 		goto out;
681 	}
682 
683 	ppp = PF_TO_PPP(pf);
684 	switch (cmd) {
685 	case PPPIOCSMRU:
686 		if (get_user(val, p))
687 			break;
688 		ppp->mru = val;
689 		err = 0;
690 		break;
691 
692 	case PPPIOCSFLAGS:
693 		if (get_user(val, p))
694 			break;
695 		ppp_lock(ppp);
696 		cflags = ppp->flags & ~val;
697 #ifdef CONFIG_PPP_MULTILINK
698 		if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
699 			ppp->nextseq = 0;
700 #endif
701 		ppp->flags = val & SC_FLAG_BITS;
702 		ppp_unlock(ppp);
703 		if (cflags & SC_CCP_OPEN)
704 			ppp_ccp_closed(ppp);
705 		err = 0;
706 		break;
707 
708 	case PPPIOCGFLAGS:
709 		val = ppp->flags | ppp->xstate | ppp->rstate;
710 		if (put_user(val, p))
711 			break;
712 		err = 0;
713 		break;
714 
715 	case PPPIOCSCOMPRESS:
716 	{
717 		struct ppp_option_data data;
718 		if (copy_from_user(&data, argp, sizeof(data)))
719 			err = -EFAULT;
720 		else
721 			err = ppp_set_compress(ppp, &data);
722 		break;
723 	}
724 	case PPPIOCGUNIT:
725 		if (put_user(ppp->file.index, p))
726 			break;
727 		err = 0;
728 		break;
729 
730 	case PPPIOCSDEBUG:
731 		if (get_user(val, p))
732 			break;
733 		ppp->debug = val;
734 		err = 0;
735 		break;
736 
737 	case PPPIOCGDEBUG:
738 		if (put_user(ppp->debug, p))
739 			break;
740 		err = 0;
741 		break;
742 
743 	case PPPIOCGIDLE32:
744                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
745                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
746                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
747 			break;
748 		err = 0;
749 		break;
750 
751 	case PPPIOCGIDLE64:
752 		idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
753 		idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
754 		if (copy_to_user(argp, &idle64, sizeof(idle64)))
755 			break;
756 		err = 0;
757 		break;
758 
759 	case PPPIOCSMAXCID:
760 		if (get_user(val, p))
761 			break;
762 		val2 = 15;
763 		if ((val >> 16) != 0) {
764 			val2 = val >> 16;
765 			val &= 0xffff;
766 		}
767 		vj = slhc_init(val2+1, val+1);
768 		if (IS_ERR(vj)) {
769 			err = PTR_ERR(vj);
770 			break;
771 		}
772 		ppp_lock(ppp);
773 		if (ppp->vj)
774 			slhc_free(ppp->vj);
775 		ppp->vj = vj;
776 		ppp_unlock(ppp);
777 		err = 0;
778 		break;
779 
780 	case PPPIOCGNPMODE:
781 	case PPPIOCSNPMODE:
782 		if (copy_from_user(&npi, argp, sizeof(npi)))
783 			break;
784 		err = proto_to_npindex(npi.protocol);
785 		if (err < 0)
786 			break;
787 		i = err;
788 		if (cmd == PPPIOCGNPMODE) {
789 			err = -EFAULT;
790 			npi.mode = ppp->npmode[i];
791 			if (copy_to_user(argp, &npi, sizeof(npi)))
792 				break;
793 		} else {
794 			ppp->npmode[i] = npi.mode;
795 			/* we may be able to transmit more packets now (??) */
796 			netif_wake_queue(ppp->dev);
797 		}
798 		err = 0;
799 		break;
800 
801 #ifdef CONFIG_PPP_FILTER
802 	case PPPIOCSPASS:
803 	case PPPIOCSACTIVE:
804 	{
805 		struct bpf_prog *filter = ppp_get_filter(argp);
806 		struct bpf_prog **which;
807 
808 		if (IS_ERR(filter)) {
809 			err = PTR_ERR(filter);
810 			break;
811 		}
812 		if (cmd == PPPIOCSPASS)
813 			which = &ppp->pass_filter;
814 		else
815 			which = &ppp->active_filter;
816 		ppp_lock(ppp);
817 		if (*which)
818 			bpf_prog_destroy(*which);
819 		*which = filter;
820 		ppp_unlock(ppp);
821 		err = 0;
822 		break;
823 	}
824 #endif /* CONFIG_PPP_FILTER */
825 
826 #ifdef CONFIG_PPP_MULTILINK
827 	case PPPIOCSMRRU:
828 		if (get_user(val, p))
829 			break;
830 		ppp_recv_lock(ppp);
831 		ppp->mrru = val;
832 		ppp_recv_unlock(ppp);
833 		err = 0;
834 		break;
835 #endif /* CONFIG_PPP_MULTILINK */
836 
837 	default:
838 		err = -ENOTTY;
839 	}
840 
841 out:
842 	mutex_unlock(&ppp_mutex);
843 
844 	return err;
845 }
846 
847 #ifdef CONFIG_COMPAT
848 struct ppp_option_data32 {
849 	compat_uptr_t		ptr;
850 	u32			length;
851 	compat_int_t		transmit;
852 };
853 #define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)
854 
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)855 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
856 {
857 	struct ppp_file *pf;
858 	int err = -ENOIOCTLCMD;
859 	void __user *argp = (void __user *)arg;
860 
861 	mutex_lock(&ppp_mutex);
862 
863 	pf = file->private_data;
864 	if (pf && pf->kind == INTERFACE) {
865 		struct ppp *ppp = PF_TO_PPP(pf);
866 		switch (cmd) {
867 #ifdef CONFIG_PPP_FILTER
868 		case PPPIOCSPASS32:
869 		case PPPIOCSACTIVE32:
870 		{
871 			struct bpf_prog *filter = compat_ppp_get_filter(argp);
872 			struct bpf_prog **which;
873 
874 			if (IS_ERR(filter)) {
875 				err = PTR_ERR(filter);
876 				break;
877 			}
878 			if (cmd == PPPIOCSPASS32)
879 				which = &ppp->pass_filter;
880 			else
881 				which = &ppp->active_filter;
882 			ppp_lock(ppp);
883 			if (*which)
884 				bpf_prog_destroy(*which);
885 			*which = filter;
886 			ppp_unlock(ppp);
887 			err = 0;
888 			break;
889 		}
890 #endif /* CONFIG_PPP_FILTER */
891 		case PPPIOCSCOMPRESS32:
892 		{
893 			struct ppp_option_data32 data32;
894 			if (copy_from_user(&data32, argp, sizeof(data32))) {
895 				err = -EFAULT;
896 			} else {
897 				struct ppp_option_data data = {
898 					.ptr = compat_ptr(data32.ptr),
899 					.length = data32.length,
900 					.transmit = data32.transmit
901 				};
902 				err = ppp_set_compress(ppp, &data);
903 			}
904 			break;
905 		}
906 		}
907 	}
908 	mutex_unlock(&ppp_mutex);
909 
910 	/* all other commands have compatible arguments */
911 	if (err == -ENOIOCTLCMD)
912 		err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
913 
914 	return err;
915 }
916 #endif
917 
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)918 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
919 			struct file *file, unsigned int cmd, unsigned long arg)
920 {
921 	int unit, err = -EFAULT;
922 	struct ppp *ppp;
923 	struct channel *chan;
924 	struct ppp_net *pn;
925 	int __user *p = (int __user *)arg;
926 
927 	switch (cmd) {
928 	case PPPIOCNEWUNIT:
929 		/* Create a new ppp unit */
930 		if (get_user(unit, p))
931 			break;
932 		err = ppp_create_interface(net, file, &unit);
933 		if (err < 0)
934 			break;
935 
936 		err = -EFAULT;
937 		if (put_user(unit, p))
938 			break;
939 		err = 0;
940 		break;
941 
942 	case PPPIOCATTACH:
943 		/* Attach to an existing ppp unit */
944 		if (get_user(unit, p))
945 			break;
946 		err = -ENXIO;
947 		pn = ppp_pernet(net);
948 		mutex_lock(&pn->all_ppp_mutex);
949 		ppp = ppp_find_unit(pn, unit);
950 		if (ppp) {
951 			refcount_inc(&ppp->file.refcnt);
952 			file->private_data = &ppp->file;
953 			err = 0;
954 		}
955 		mutex_unlock(&pn->all_ppp_mutex);
956 		break;
957 
958 	case PPPIOCATTCHAN:
959 		if (get_user(unit, p))
960 			break;
961 		err = -ENXIO;
962 		pn = ppp_pernet(net);
963 		spin_lock_bh(&pn->all_channels_lock);
964 		chan = ppp_find_channel(pn, unit);
965 		if (chan) {
966 			refcount_inc(&chan->file.refcnt);
967 			file->private_data = &chan->file;
968 			err = 0;
969 		}
970 		spin_unlock_bh(&pn->all_channels_lock);
971 		break;
972 
973 	default:
974 		err = -ENOTTY;
975 	}
976 
977 	return err;
978 }
979 
980 static const struct file_operations ppp_device_fops = {
981 	.owner		= THIS_MODULE,
982 	.read		= ppp_read,
983 	.write		= ppp_write,
984 	.poll		= ppp_poll,
985 	.unlocked_ioctl	= ppp_ioctl,
986 #ifdef CONFIG_COMPAT
987 	.compat_ioctl	= ppp_compat_ioctl,
988 #endif
989 	.open		= ppp_open,
990 	.release	= ppp_release,
991 	.llseek		= noop_llseek,
992 };
993 
ppp_init_net(struct net * net)994 static __net_init int ppp_init_net(struct net *net)
995 {
996 	struct ppp_net *pn = net_generic(net, ppp_net_id);
997 
998 	idr_init(&pn->units_idr);
999 	mutex_init(&pn->all_ppp_mutex);
1000 
1001 	INIT_LIST_HEAD(&pn->all_channels);
1002 	INIT_LIST_HEAD(&pn->new_channels);
1003 
1004 	spin_lock_init(&pn->all_channels_lock);
1005 
1006 	return 0;
1007 }
1008 
ppp_exit_net(struct net * net)1009 static __net_exit void ppp_exit_net(struct net *net)
1010 {
1011 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1012 	struct net_device *dev;
1013 	struct net_device *aux;
1014 	struct ppp *ppp;
1015 	LIST_HEAD(list);
1016 	int id;
1017 
1018 	rtnl_lock();
1019 	for_each_netdev_safe(net, dev, aux) {
1020 		if (dev->netdev_ops == &ppp_netdev_ops)
1021 			unregister_netdevice_queue(dev, &list);
1022 	}
1023 
1024 	idr_for_each_entry(&pn->units_idr, ppp, id)
1025 		/* Skip devices already unregistered by previous loop */
1026 		if (!net_eq(dev_net(ppp->dev), net))
1027 			unregister_netdevice_queue(ppp->dev, &list);
1028 
1029 	unregister_netdevice_many(&list);
1030 	rtnl_unlock();
1031 
1032 	mutex_destroy(&pn->all_ppp_mutex);
1033 	idr_destroy(&pn->units_idr);
1034 	WARN_ON_ONCE(!list_empty(&pn->all_channels));
1035 	WARN_ON_ONCE(!list_empty(&pn->new_channels));
1036 }
1037 
1038 static struct pernet_operations ppp_net_ops = {
1039 	.init = ppp_init_net,
1040 	.exit = ppp_exit_net,
1041 	.id   = &ppp_net_id,
1042 	.size = sizeof(struct ppp_net),
1043 };
1044 
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1045 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1046 {
1047 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1048 	int ret;
1049 
1050 	mutex_lock(&pn->all_ppp_mutex);
1051 
1052 	if (unit < 0) {
1053 		ret = unit_get(&pn->units_idr, ppp, 0);
1054 		if (ret < 0)
1055 			goto err;
1056 		if (!ifname_is_set) {
1057 			while (1) {
1058 				snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1059 				if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name))
1060 					break;
1061 				unit_put(&pn->units_idr, ret);
1062 				ret = unit_get(&pn->units_idr, ppp, ret + 1);
1063 				if (ret < 0)
1064 					goto err;
1065 			}
1066 		}
1067 	} else {
1068 		/* Caller asked for a specific unit number. Fail with -EEXIST
1069 		 * if unavailable. For backward compatibility, return -EEXIST
1070 		 * too if idr allocation fails; this makes pppd retry without
1071 		 * requesting a specific unit number.
1072 		 */
1073 		if (unit_find(&pn->units_idr, unit)) {
1074 			ret = -EEXIST;
1075 			goto err;
1076 		}
1077 		ret = unit_set(&pn->units_idr, ppp, unit);
1078 		if (ret < 0) {
1079 			/* Rewrite error for backward compatibility */
1080 			ret = -EEXIST;
1081 			goto err;
1082 		}
1083 	}
1084 	ppp->file.index = ret;
1085 
1086 	if (!ifname_is_set)
1087 		snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1088 
1089 	mutex_unlock(&pn->all_ppp_mutex);
1090 
1091 	ret = register_netdevice(ppp->dev);
1092 	if (ret < 0)
1093 		goto err_unit;
1094 
1095 	atomic_inc(&ppp_unit_count);
1096 
1097 	return 0;
1098 
1099 err_unit:
1100 	mutex_lock(&pn->all_ppp_mutex);
1101 	unit_put(&pn->units_idr, ppp->file.index);
1102 err:
1103 	mutex_unlock(&pn->all_ppp_mutex);
1104 
1105 	return ret;
1106 }
1107 
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1108 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1109 			     const struct ppp_config *conf)
1110 {
1111 	struct ppp *ppp = netdev_priv(dev);
1112 	int indx;
1113 	int err;
1114 	int cpu;
1115 
1116 	ppp->dev = dev;
1117 	ppp->ppp_net = src_net;
1118 	ppp->mru = PPP_MRU;
1119 	ppp->owner = conf->file;
1120 
1121 	init_ppp_file(&ppp->file, INTERFACE);
1122 	ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1123 
1124 	for (indx = 0; indx < NUM_NP; ++indx)
1125 		ppp->npmode[indx] = NPMODE_PASS;
1126 	INIT_LIST_HEAD(&ppp->channels);
1127 	spin_lock_init(&ppp->rlock);
1128 	spin_lock_init(&ppp->wlock);
1129 
1130 	ppp->xmit_recursion = alloc_percpu(int);
1131 	if (!ppp->xmit_recursion) {
1132 		err = -ENOMEM;
1133 		goto err1;
1134 	}
1135 	for_each_possible_cpu(cpu)
1136 		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1137 
1138 #ifdef CONFIG_PPP_MULTILINK
1139 	ppp->minseq = -1;
1140 	skb_queue_head_init(&ppp->mrq);
1141 #endif /* CONFIG_PPP_MULTILINK */
1142 #ifdef CONFIG_PPP_FILTER
1143 	ppp->pass_filter = NULL;
1144 	ppp->active_filter = NULL;
1145 #endif /* CONFIG_PPP_FILTER */
1146 
1147 	err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1148 	if (err < 0)
1149 		goto err2;
1150 
1151 	conf->file->private_data = &ppp->file;
1152 
1153 	return 0;
1154 err2:
1155 	free_percpu(ppp->xmit_recursion);
1156 err1:
1157 	return err;
1158 }
1159 
1160 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1161 	[IFLA_PPP_DEV_FD]	= { .type = NLA_S32 },
1162 };
1163 
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1164 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1165 			   struct netlink_ext_ack *extack)
1166 {
1167 	if (!data)
1168 		return -EINVAL;
1169 
1170 	if (!data[IFLA_PPP_DEV_FD])
1171 		return -EINVAL;
1172 	if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1173 		return -EBADF;
1174 
1175 	return 0;
1176 }
1177 
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1178 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1179 			  struct nlattr *tb[], struct nlattr *data[],
1180 			  struct netlink_ext_ack *extack)
1181 {
1182 	struct ppp_config conf = {
1183 		.unit = -1,
1184 		.ifname_is_set = true,
1185 	};
1186 	struct file *file;
1187 	int err;
1188 
1189 	file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1190 	if (!file)
1191 		return -EBADF;
1192 
1193 	/* rtnl_lock is already held here, but ppp_create_interface() locks
1194 	 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1195 	 * possible deadlock due to lock order inversion, at the cost of
1196 	 * pushing the problem back to userspace.
1197 	 */
1198 	if (!mutex_trylock(&ppp_mutex)) {
1199 		err = -EBUSY;
1200 		goto out;
1201 	}
1202 
1203 	if (file->f_op != &ppp_device_fops || file->private_data) {
1204 		err = -EBADF;
1205 		goto out_unlock;
1206 	}
1207 
1208 	conf.file = file;
1209 
1210 	/* Don't use device name generated by the rtnetlink layer when ifname
1211 	 * isn't specified. Let ppp_dev_configure() set the device name using
1212 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1213 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1214 	 */
1215 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1216 		conf.ifname_is_set = false;
1217 
1218 	err = ppp_dev_configure(src_net, dev, &conf);
1219 
1220 out_unlock:
1221 	mutex_unlock(&ppp_mutex);
1222 out:
1223 	fput(file);
1224 
1225 	return err;
1226 }
1227 
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1228 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1229 {
1230 	unregister_netdevice_queue(dev, head);
1231 }
1232 
ppp_nl_get_size(const struct net_device * dev)1233 static size_t ppp_nl_get_size(const struct net_device *dev)
1234 {
1235 	return 0;
1236 }
1237 
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1238 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1239 {
1240 	return 0;
1241 }
1242 
ppp_nl_get_link_net(const struct net_device * dev)1243 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1244 {
1245 	struct ppp *ppp = netdev_priv(dev);
1246 
1247 	return ppp->ppp_net;
1248 }
1249 
1250 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1251 	.kind		= "ppp",
1252 	.maxtype	= IFLA_PPP_MAX,
1253 	.policy		= ppp_nl_policy,
1254 	.priv_size	= sizeof(struct ppp),
1255 	.setup		= ppp_setup,
1256 	.validate	= ppp_nl_validate,
1257 	.newlink	= ppp_nl_newlink,
1258 	.dellink	= ppp_nl_dellink,
1259 	.get_size	= ppp_nl_get_size,
1260 	.fill_info	= ppp_nl_fill_info,
1261 	.get_link_net	= ppp_nl_get_link_net,
1262 };
1263 
1264 #define PPP_MAJOR	108
1265 
1266 /* Called at boot time if ppp is compiled into the kernel,
1267    or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1268 static int __init ppp_init(void)
1269 {
1270 	int err;
1271 
1272 	pr_info("PPP generic driver version " PPP_VERSION "\n");
1273 
1274 	err = register_pernet_device(&ppp_net_ops);
1275 	if (err) {
1276 		pr_err("failed to register PPP pernet device (%d)\n", err);
1277 		goto out;
1278 	}
1279 
1280 	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1281 	if (err) {
1282 		pr_err("failed to register PPP device (%d)\n", err);
1283 		goto out_net;
1284 	}
1285 
1286 	ppp_class = class_create(THIS_MODULE, "ppp");
1287 	if (IS_ERR(ppp_class)) {
1288 		err = PTR_ERR(ppp_class);
1289 		goto out_chrdev;
1290 	}
1291 
1292 	err = rtnl_link_register(&ppp_link_ops);
1293 	if (err) {
1294 		pr_err("failed to register rtnetlink PPP handler\n");
1295 		goto out_class;
1296 	}
1297 
1298 	/* not a big deal if we fail here :-) */
1299 	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1300 
1301 	return 0;
1302 
1303 out_class:
1304 	class_destroy(ppp_class);
1305 out_chrdev:
1306 	unregister_chrdev(PPP_MAJOR, "ppp");
1307 out_net:
1308 	unregister_pernet_device(&ppp_net_ops);
1309 out:
1310 	return err;
1311 }
1312 
1313 /*
1314  * Network interface unit routines.
1315  */
1316 static netdev_tx_t
ppp_start_xmit(struct sk_buff * skb,struct net_device * dev)1317 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1318 {
1319 	struct ppp *ppp = netdev_priv(dev);
1320 	int npi, proto;
1321 	unsigned char *pp;
1322 
1323 	npi = ethertype_to_npindex(ntohs(skb->protocol));
1324 	if (npi < 0)
1325 		goto outf;
1326 
1327 	/* Drop, accept or reject the packet */
1328 	switch (ppp->npmode[npi]) {
1329 	case NPMODE_PASS:
1330 		break;
1331 	case NPMODE_QUEUE:
1332 		/* it would be nice to have a way to tell the network
1333 		   system to queue this one up for later. */
1334 		goto outf;
1335 	case NPMODE_DROP:
1336 	case NPMODE_ERROR:
1337 		goto outf;
1338 	}
1339 
1340 	/* Put the 2-byte PPP protocol number on the front,
1341 	   making sure there is room for the address and control fields. */
1342 	if (skb_cow_head(skb, PPP_HDRLEN))
1343 		goto outf;
1344 
1345 	pp = skb_push(skb, 2);
1346 	proto = npindex_to_proto[npi];
1347 	put_unaligned_be16(proto, pp);
1348 
1349 	skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1350 	ppp_xmit_process(ppp, skb);
1351 
1352 	return NETDEV_TX_OK;
1353 
1354  outf:
1355 	kfree_skb(skb);
1356 	++dev->stats.tx_dropped;
1357 	return NETDEV_TX_OK;
1358 }
1359 
1360 static int
ppp_net_ioctl(struct net_device * dev,struct ifreq * ifr,int cmd)1361 ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1362 {
1363 	struct ppp *ppp = netdev_priv(dev);
1364 	int err = -EFAULT;
1365 	void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1366 	struct ppp_stats stats;
1367 	struct ppp_comp_stats cstats;
1368 	char *vers;
1369 
1370 	switch (cmd) {
1371 	case SIOCGPPPSTATS:
1372 		ppp_get_stats(ppp, &stats);
1373 		if (copy_to_user(addr, &stats, sizeof(stats)))
1374 			break;
1375 		err = 0;
1376 		break;
1377 
1378 	case SIOCGPPPCSTATS:
1379 		memset(&cstats, 0, sizeof(cstats));
1380 		if (ppp->xc_state)
1381 			ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1382 		if (ppp->rc_state)
1383 			ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1384 		if (copy_to_user(addr, &cstats, sizeof(cstats)))
1385 			break;
1386 		err = 0;
1387 		break;
1388 
1389 	case SIOCGPPPVER:
1390 		vers = PPP_VERSION;
1391 		if (copy_to_user(addr, vers, strlen(vers) + 1))
1392 			break;
1393 		err = 0;
1394 		break;
1395 
1396 	default:
1397 		err = -EINVAL;
1398 	}
1399 
1400 	return err;
1401 }
1402 
1403 static void
ppp_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats64)1404 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1405 {
1406 	struct ppp *ppp = netdev_priv(dev);
1407 
1408 	ppp_recv_lock(ppp);
1409 	stats64->rx_packets = ppp->stats64.rx_packets;
1410 	stats64->rx_bytes   = ppp->stats64.rx_bytes;
1411 	ppp_recv_unlock(ppp);
1412 
1413 	ppp_xmit_lock(ppp);
1414 	stats64->tx_packets = ppp->stats64.tx_packets;
1415 	stats64->tx_bytes   = ppp->stats64.tx_bytes;
1416 	ppp_xmit_unlock(ppp);
1417 
1418 	stats64->rx_errors        = dev->stats.rx_errors;
1419 	stats64->tx_errors        = dev->stats.tx_errors;
1420 	stats64->rx_dropped       = dev->stats.rx_dropped;
1421 	stats64->tx_dropped       = dev->stats.tx_dropped;
1422 	stats64->rx_length_errors = dev->stats.rx_length_errors;
1423 }
1424 
ppp_dev_init(struct net_device * dev)1425 static int ppp_dev_init(struct net_device *dev)
1426 {
1427 	struct ppp *ppp;
1428 
1429 	netdev_lockdep_set_classes(dev);
1430 
1431 	ppp = netdev_priv(dev);
1432 	/* Let the netdevice take a reference on the ppp file. This ensures
1433 	 * that ppp_destroy_interface() won't run before the device gets
1434 	 * unregistered.
1435 	 */
1436 	refcount_inc(&ppp->file.refcnt);
1437 
1438 	return 0;
1439 }
1440 
ppp_dev_uninit(struct net_device * dev)1441 static void ppp_dev_uninit(struct net_device *dev)
1442 {
1443 	struct ppp *ppp = netdev_priv(dev);
1444 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1445 
1446 	ppp_lock(ppp);
1447 	ppp->closing = 1;
1448 	ppp_unlock(ppp);
1449 
1450 	mutex_lock(&pn->all_ppp_mutex);
1451 	unit_put(&pn->units_idr, ppp->file.index);
1452 	mutex_unlock(&pn->all_ppp_mutex);
1453 
1454 	ppp->owner = NULL;
1455 
1456 	ppp->file.dead = 1;
1457 	wake_up_interruptible(&ppp->file.rwait);
1458 }
1459 
ppp_dev_priv_destructor(struct net_device * dev)1460 static void ppp_dev_priv_destructor(struct net_device *dev)
1461 {
1462 	struct ppp *ppp;
1463 
1464 	ppp = netdev_priv(dev);
1465 	if (refcount_dec_and_test(&ppp->file.refcnt))
1466 		ppp_destroy_interface(ppp);
1467 }
1468 
1469 static const struct net_device_ops ppp_netdev_ops = {
1470 	.ndo_init	 = ppp_dev_init,
1471 	.ndo_uninit      = ppp_dev_uninit,
1472 	.ndo_start_xmit  = ppp_start_xmit,
1473 	.ndo_do_ioctl    = ppp_net_ioctl,
1474 	.ndo_get_stats64 = ppp_get_stats64,
1475 };
1476 
1477 static struct device_type ppp_type = {
1478 	.name = "ppp",
1479 };
1480 
ppp_setup(struct net_device * dev)1481 static void ppp_setup(struct net_device *dev)
1482 {
1483 	dev->netdev_ops = &ppp_netdev_ops;
1484 	SET_NETDEV_DEVTYPE(dev, &ppp_type);
1485 
1486 	dev->features |= NETIF_F_LLTX;
1487 
1488 	dev->hard_header_len = PPP_HDRLEN;
1489 	dev->mtu = PPP_MRU;
1490 	dev->addr_len = 0;
1491 	dev->tx_queue_len = 3;
1492 	dev->type = ARPHRD_PPP;
1493 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1494 	dev->priv_destructor = ppp_dev_priv_destructor;
1495 	netif_keep_dst(dev);
1496 }
1497 
1498 /*
1499  * Transmit-side routines.
1500  */
1501 
1502 /* Called to do any work queued up on the transmit side that can now be done */
__ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1503 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1504 {
1505 	ppp_xmit_lock(ppp);
1506 	if (!ppp->closing) {
1507 		ppp_push(ppp);
1508 
1509 		if (skb)
1510 			skb_queue_tail(&ppp->file.xq, skb);
1511 		while (!ppp->xmit_pending &&
1512 		       (skb = skb_dequeue(&ppp->file.xq)))
1513 			ppp_send_frame(ppp, skb);
1514 		/* If there's no work left to do, tell the core net
1515 		   code that we can accept some more. */
1516 		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1517 			netif_wake_queue(ppp->dev);
1518 		else
1519 			netif_stop_queue(ppp->dev);
1520 	} else {
1521 		kfree_skb(skb);
1522 	}
1523 	ppp_xmit_unlock(ppp);
1524 }
1525 
ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1526 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1527 {
1528 	local_bh_disable();
1529 
1530 	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1531 		goto err;
1532 
1533 	(*this_cpu_ptr(ppp->xmit_recursion))++;
1534 	__ppp_xmit_process(ppp, skb);
1535 	(*this_cpu_ptr(ppp->xmit_recursion))--;
1536 
1537 	local_bh_enable();
1538 
1539 	return;
1540 
1541 err:
1542 	local_bh_enable();
1543 
1544 	kfree_skb(skb);
1545 
1546 	if (net_ratelimit())
1547 		netdev_err(ppp->dev, "recursion detected\n");
1548 }
1549 
1550 static inline struct sk_buff *
pad_compress_skb(struct ppp * ppp,struct sk_buff * skb)1551 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1552 {
1553 	struct sk_buff *new_skb;
1554 	int len;
1555 	int new_skb_size = ppp->dev->mtu +
1556 		ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1557 	int compressor_skb_size = ppp->dev->mtu +
1558 		ppp->xcomp->comp_extra + PPP_HDRLEN;
1559 	new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1560 	if (!new_skb) {
1561 		if (net_ratelimit())
1562 			netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1563 		return NULL;
1564 	}
1565 	if (ppp->dev->hard_header_len > PPP_HDRLEN)
1566 		skb_reserve(new_skb,
1567 			    ppp->dev->hard_header_len - PPP_HDRLEN);
1568 
1569 	/* compressor still expects A/C bytes in hdr */
1570 	len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1571 				   new_skb->data, skb->len + 2,
1572 				   compressor_skb_size);
1573 	if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1574 		consume_skb(skb);
1575 		skb = new_skb;
1576 		skb_put(skb, len);
1577 		skb_pull(skb, 2);	/* pull off A/C bytes */
1578 	} else if (len == 0) {
1579 		/* didn't compress, or CCP not up yet */
1580 		consume_skb(new_skb);
1581 		new_skb = skb;
1582 	} else {
1583 		/*
1584 		 * (len < 0)
1585 		 * MPPE requires that we do not send unencrypted
1586 		 * frames.  The compressor will return -1 if we
1587 		 * should drop the frame.  We cannot simply test
1588 		 * the compress_proto because MPPE and MPPC share
1589 		 * the same number.
1590 		 */
1591 		if (net_ratelimit())
1592 			netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1593 		kfree_skb(skb);
1594 		consume_skb(new_skb);
1595 		new_skb = NULL;
1596 	}
1597 	return new_skb;
1598 }
1599 
1600 /*
1601  * Compress and send a frame.
1602  * The caller should have locked the xmit path,
1603  * and xmit_pending should be 0.
1604  */
1605 static void
ppp_send_frame(struct ppp * ppp,struct sk_buff * skb)1606 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1607 {
1608 	int proto = PPP_PROTO(skb);
1609 	struct sk_buff *new_skb;
1610 	int len;
1611 	unsigned char *cp;
1612 
1613 	if (proto < 0x8000) {
1614 #ifdef CONFIG_PPP_FILTER
1615 		/* check if we should pass this packet */
1616 		/* the filter instructions are constructed assuming
1617 		   a four-byte PPP header on each packet */
1618 		*(u8 *)skb_push(skb, 2) = 1;
1619 		if (ppp->pass_filter &&
1620 		    BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
1621 			if (ppp->debug & 1)
1622 				netdev_printk(KERN_DEBUG, ppp->dev,
1623 					      "PPP: outbound frame "
1624 					      "not passed\n");
1625 			kfree_skb(skb);
1626 			return;
1627 		}
1628 		/* if this packet passes the active filter, record the time */
1629 		if (!(ppp->active_filter &&
1630 		      BPF_PROG_RUN(ppp->active_filter, skb) == 0))
1631 			ppp->last_xmit = jiffies;
1632 		skb_pull(skb, 2);
1633 #else
1634 		/* for data packets, record the time */
1635 		ppp->last_xmit = jiffies;
1636 #endif /* CONFIG_PPP_FILTER */
1637 	}
1638 
1639 	++ppp->stats64.tx_packets;
1640 	ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1641 
1642 	switch (proto) {
1643 	case PPP_IP:
1644 		if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1645 			break;
1646 		/* try to do VJ TCP header compression */
1647 		new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1648 				    GFP_ATOMIC);
1649 		if (!new_skb) {
1650 			netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1651 			goto drop;
1652 		}
1653 		skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1654 		cp = skb->data + 2;
1655 		len = slhc_compress(ppp->vj, cp, skb->len - 2,
1656 				    new_skb->data + 2, &cp,
1657 				    !(ppp->flags & SC_NO_TCP_CCID));
1658 		if (cp == skb->data + 2) {
1659 			/* didn't compress */
1660 			consume_skb(new_skb);
1661 		} else {
1662 			if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1663 				proto = PPP_VJC_COMP;
1664 				cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1665 			} else {
1666 				proto = PPP_VJC_UNCOMP;
1667 				cp[0] = skb->data[2];
1668 			}
1669 			consume_skb(skb);
1670 			skb = new_skb;
1671 			cp = skb_put(skb, len + 2);
1672 			cp[0] = 0;
1673 			cp[1] = proto;
1674 		}
1675 		break;
1676 
1677 	case PPP_CCP:
1678 		/* peek at outbound CCP frames */
1679 		ppp_ccp_peek(ppp, skb, 0);
1680 		break;
1681 	}
1682 
1683 	/* try to do packet compression */
1684 	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1685 	    proto != PPP_LCP && proto != PPP_CCP) {
1686 		if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1687 			if (net_ratelimit())
1688 				netdev_err(ppp->dev,
1689 					   "ppp: compression required but "
1690 					   "down - pkt dropped.\n");
1691 			goto drop;
1692 		}
1693 		skb = pad_compress_skb(ppp, skb);
1694 		if (!skb)
1695 			goto drop;
1696 	}
1697 
1698 	/*
1699 	 * If we are waiting for traffic (demand dialling),
1700 	 * queue it up for pppd to receive.
1701 	 */
1702 	if (ppp->flags & SC_LOOP_TRAFFIC) {
1703 		if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1704 			goto drop;
1705 		skb_queue_tail(&ppp->file.rq, skb);
1706 		wake_up_interruptible(&ppp->file.rwait);
1707 		return;
1708 	}
1709 
1710 	ppp->xmit_pending = skb;
1711 	ppp_push(ppp);
1712 	return;
1713 
1714  drop:
1715 	kfree_skb(skb);
1716 	++ppp->dev->stats.tx_errors;
1717 }
1718 
1719 /*
1720  * Try to send the frame in xmit_pending.
1721  * The caller should have the xmit path locked.
1722  */
1723 static void
ppp_push(struct ppp * ppp)1724 ppp_push(struct ppp *ppp)
1725 {
1726 	struct list_head *list;
1727 	struct channel *pch;
1728 	struct sk_buff *skb = ppp->xmit_pending;
1729 
1730 	if (!skb)
1731 		return;
1732 
1733 	list = &ppp->channels;
1734 	if (list_empty(list)) {
1735 		/* nowhere to send the packet, just drop it */
1736 		ppp->xmit_pending = NULL;
1737 		kfree_skb(skb);
1738 		return;
1739 	}
1740 
1741 	if ((ppp->flags & SC_MULTILINK) == 0) {
1742 		/* not doing multilink: send it down the first channel */
1743 		list = list->next;
1744 		pch = list_entry(list, struct channel, clist);
1745 
1746 		spin_lock(&pch->downl);
1747 		if (pch->chan) {
1748 			if (pch->chan->ops->start_xmit(pch->chan, skb))
1749 				ppp->xmit_pending = NULL;
1750 		} else {
1751 			/* channel got unregistered */
1752 			kfree_skb(skb);
1753 			ppp->xmit_pending = NULL;
1754 		}
1755 		spin_unlock(&pch->downl);
1756 		return;
1757 	}
1758 
1759 #ifdef CONFIG_PPP_MULTILINK
1760 	/* Multilink: fragment the packet over as many links
1761 	   as can take the packet at the moment. */
1762 	if (!ppp_mp_explode(ppp, skb))
1763 		return;
1764 #endif /* CONFIG_PPP_MULTILINK */
1765 
1766 	ppp->xmit_pending = NULL;
1767 	kfree_skb(skb);
1768 }
1769 
1770 #ifdef CONFIG_PPP_MULTILINK
1771 static bool mp_protocol_compress __read_mostly = true;
1772 module_param(mp_protocol_compress, bool, 0644);
1773 MODULE_PARM_DESC(mp_protocol_compress,
1774 		 "compress protocol id in multilink fragments");
1775 
1776 /*
1777  * Divide a packet to be transmitted into fragments and
1778  * send them out the individual links.
1779  */
ppp_mp_explode(struct ppp * ppp,struct sk_buff * skb)1780 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1781 {
1782 	int len, totlen;
1783 	int i, bits, hdrlen, mtu;
1784 	int flen;
1785 	int navail, nfree, nzero;
1786 	int nbigger;
1787 	int totspeed;
1788 	int totfree;
1789 	unsigned char *p, *q;
1790 	struct list_head *list;
1791 	struct channel *pch;
1792 	struct sk_buff *frag;
1793 	struct ppp_channel *chan;
1794 
1795 	totspeed = 0; /*total bitrate of the bundle*/
1796 	nfree = 0; /* # channels which have no packet already queued */
1797 	navail = 0; /* total # of usable channels (not deregistered) */
1798 	nzero = 0; /* number of channels with zero speed associated*/
1799 	totfree = 0; /*total # of channels available and
1800 				  *having no queued packets before
1801 				  *starting the fragmentation*/
1802 
1803 	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1804 	i = 0;
1805 	list_for_each_entry(pch, &ppp->channels, clist) {
1806 		if (pch->chan) {
1807 			pch->avail = 1;
1808 			navail++;
1809 			pch->speed = pch->chan->speed;
1810 		} else {
1811 			pch->avail = 0;
1812 		}
1813 		if (pch->avail) {
1814 			if (skb_queue_empty(&pch->file.xq) ||
1815 				!pch->had_frag) {
1816 					if (pch->speed == 0)
1817 						nzero++;
1818 					else
1819 						totspeed += pch->speed;
1820 
1821 					pch->avail = 2;
1822 					++nfree;
1823 					++totfree;
1824 				}
1825 			if (!pch->had_frag && i < ppp->nxchan)
1826 				ppp->nxchan = i;
1827 		}
1828 		++i;
1829 	}
1830 	/*
1831 	 * Don't start sending this packet unless at least half of
1832 	 * the channels are free.  This gives much better TCP
1833 	 * performance if we have a lot of channels.
1834 	 */
1835 	if (nfree == 0 || nfree < navail / 2)
1836 		return 0; /* can't take now, leave it in xmit_pending */
1837 
1838 	/* Do protocol field compression */
1839 	p = skb->data;
1840 	len = skb->len;
1841 	if (*p == 0 && mp_protocol_compress) {
1842 		++p;
1843 		--len;
1844 	}
1845 
1846 	totlen = len;
1847 	nbigger = len % nfree;
1848 
1849 	/* skip to the channel after the one we last used
1850 	   and start at that one */
1851 	list = &ppp->channels;
1852 	for (i = 0; i < ppp->nxchan; ++i) {
1853 		list = list->next;
1854 		if (list == &ppp->channels) {
1855 			i = 0;
1856 			break;
1857 		}
1858 	}
1859 
1860 	/* create a fragment for each channel */
1861 	bits = B;
1862 	while (len > 0) {
1863 		list = list->next;
1864 		if (list == &ppp->channels) {
1865 			i = 0;
1866 			continue;
1867 		}
1868 		pch = list_entry(list, struct channel, clist);
1869 		++i;
1870 		if (!pch->avail)
1871 			continue;
1872 
1873 		/*
1874 		 * Skip this channel if it has a fragment pending already and
1875 		 * we haven't given a fragment to all of the free channels.
1876 		 */
1877 		if (pch->avail == 1) {
1878 			if (nfree > 0)
1879 				continue;
1880 		} else {
1881 			pch->avail = 1;
1882 		}
1883 
1884 		/* check the channel's mtu and whether it is still attached. */
1885 		spin_lock(&pch->downl);
1886 		if (pch->chan == NULL) {
1887 			/* can't use this channel, it's being deregistered */
1888 			if (pch->speed == 0)
1889 				nzero--;
1890 			else
1891 				totspeed -= pch->speed;
1892 
1893 			spin_unlock(&pch->downl);
1894 			pch->avail = 0;
1895 			totlen = len;
1896 			totfree--;
1897 			nfree--;
1898 			if (--navail == 0)
1899 				break;
1900 			continue;
1901 		}
1902 
1903 		/*
1904 		*if the channel speed is not set divide
1905 		*the packet evenly among the free channels;
1906 		*otherwise divide it according to the speed
1907 		*of the channel we are going to transmit on
1908 		*/
1909 		flen = len;
1910 		if (nfree > 0) {
1911 			if (pch->speed == 0) {
1912 				flen = len/nfree;
1913 				if (nbigger > 0) {
1914 					flen++;
1915 					nbigger--;
1916 				}
1917 			} else {
1918 				flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1919 					((totspeed*totfree)/pch->speed)) - hdrlen;
1920 				if (nbigger > 0) {
1921 					flen += ((totfree - nzero)*pch->speed)/totspeed;
1922 					nbigger -= ((totfree - nzero)*pch->speed)/
1923 							totspeed;
1924 				}
1925 			}
1926 			nfree--;
1927 		}
1928 
1929 		/*
1930 		 *check if we are on the last channel or
1931 		 *we exceded the length of the data to
1932 		 *fragment
1933 		 */
1934 		if ((nfree <= 0) || (flen > len))
1935 			flen = len;
1936 		/*
1937 		 *it is not worth to tx on slow channels:
1938 		 *in that case from the resulting flen according to the
1939 		 *above formula will be equal or less than zero.
1940 		 *Skip the channel in this case
1941 		 */
1942 		if (flen <= 0) {
1943 			pch->avail = 2;
1944 			spin_unlock(&pch->downl);
1945 			continue;
1946 		}
1947 
1948 		/*
1949 		 * hdrlen includes the 2-byte PPP protocol field, but the
1950 		 * MTU counts only the payload excluding the protocol field.
1951 		 * (RFC1661 Section 2)
1952 		 */
1953 		mtu = pch->chan->mtu - (hdrlen - 2);
1954 		if (mtu < 4)
1955 			mtu = 4;
1956 		if (flen > mtu)
1957 			flen = mtu;
1958 		if (flen == len)
1959 			bits |= E;
1960 		frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1961 		if (!frag)
1962 			goto noskb;
1963 		q = skb_put(frag, flen + hdrlen);
1964 
1965 		/* make the MP header */
1966 		put_unaligned_be16(PPP_MP, q);
1967 		if (ppp->flags & SC_MP_XSHORTSEQ) {
1968 			q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1969 			q[3] = ppp->nxseq;
1970 		} else {
1971 			q[2] = bits;
1972 			q[3] = ppp->nxseq >> 16;
1973 			q[4] = ppp->nxseq >> 8;
1974 			q[5] = ppp->nxseq;
1975 		}
1976 
1977 		memcpy(q + hdrlen, p, flen);
1978 
1979 		/* try to send it down the channel */
1980 		chan = pch->chan;
1981 		if (!skb_queue_empty(&pch->file.xq) ||
1982 			!chan->ops->start_xmit(chan, frag))
1983 			skb_queue_tail(&pch->file.xq, frag);
1984 		pch->had_frag = 1;
1985 		p += flen;
1986 		len -= flen;
1987 		++ppp->nxseq;
1988 		bits = 0;
1989 		spin_unlock(&pch->downl);
1990 	}
1991 	ppp->nxchan = i;
1992 
1993 	return 1;
1994 
1995  noskb:
1996 	spin_unlock(&pch->downl);
1997 	if (ppp->debug & 1)
1998 		netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
1999 	++ppp->dev->stats.tx_errors;
2000 	++ppp->nxseq;
2001 	return 1;	/* abandon the frame */
2002 }
2003 #endif /* CONFIG_PPP_MULTILINK */
2004 
2005 /* Try to send data out on a channel */
__ppp_channel_push(struct channel * pch)2006 static void __ppp_channel_push(struct channel *pch)
2007 {
2008 	struct sk_buff *skb;
2009 	struct ppp *ppp;
2010 
2011 	spin_lock(&pch->downl);
2012 	if (pch->chan) {
2013 		while (!skb_queue_empty(&pch->file.xq)) {
2014 			skb = skb_dequeue(&pch->file.xq);
2015 			if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2016 				/* put the packet back and try again later */
2017 				skb_queue_head(&pch->file.xq, skb);
2018 				break;
2019 			}
2020 		}
2021 	} else {
2022 		/* channel got deregistered */
2023 		skb_queue_purge(&pch->file.xq);
2024 	}
2025 	spin_unlock(&pch->downl);
2026 	/* see if there is anything from the attached unit to be sent */
2027 	if (skb_queue_empty(&pch->file.xq)) {
2028 		ppp = pch->ppp;
2029 		if (ppp)
2030 			__ppp_xmit_process(ppp, NULL);
2031 	}
2032 }
2033 
ppp_channel_push(struct channel * pch)2034 static void ppp_channel_push(struct channel *pch)
2035 {
2036 	read_lock_bh(&pch->upl);
2037 	if (pch->ppp) {
2038 		(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2039 		__ppp_channel_push(pch);
2040 		(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2041 	} else {
2042 		__ppp_channel_push(pch);
2043 	}
2044 	read_unlock_bh(&pch->upl);
2045 }
2046 
2047 /*
2048  * Receive-side routines.
2049  */
2050 
2051 struct ppp_mp_skb_parm {
2052 	u32		sequence;
2053 	u8		BEbits;
2054 };
2055 #define PPP_MP_CB(skb)	((struct ppp_mp_skb_parm *)((skb)->cb))
2056 
2057 static inline void
ppp_do_recv(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2058 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2059 {
2060 	ppp_recv_lock(ppp);
2061 	if (!ppp->closing)
2062 		ppp_receive_frame(ppp, skb, pch);
2063 	else
2064 		kfree_skb(skb);
2065 	ppp_recv_unlock(ppp);
2066 }
2067 
2068 /**
2069  * __ppp_decompress_proto - Decompress protocol field, slim version.
2070  * @skb: Socket buffer where protocol field should be decompressed. It must have
2071  *	 at least 1 byte of head room and 1 byte of linear data. First byte of
2072  *	 data must be a protocol field byte.
2073  *
2074  * Decompress protocol field in PPP header if it's compressed, e.g. when
2075  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2076  * length are done in this function.
2077  */
__ppp_decompress_proto(struct sk_buff * skb)2078 static void __ppp_decompress_proto(struct sk_buff *skb)
2079 {
2080 	if (skb->data[0] & 0x01)
2081 		*(u8 *)skb_push(skb, 1) = 0x00;
2082 }
2083 
2084 /**
2085  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2086  * @skb: Socket buffer where protocol field should be decompressed. First byte
2087  *	 of data must be a protocol field byte.
2088  *
2089  * Decompress protocol field in PPP header if it's compressed, e.g. when
2090  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2091  * sure that skb data room is sufficient for Protocol field, before and after
2092  * decompression.
2093  *
2094  * Return: true - decompressed successfully, false - not enough room in skb.
2095  */
ppp_decompress_proto(struct sk_buff * skb)2096 static bool ppp_decompress_proto(struct sk_buff *skb)
2097 {
2098 	/* At least one byte should be present (if protocol is compressed) */
2099 	if (!pskb_may_pull(skb, 1))
2100 		return false;
2101 
2102 	__ppp_decompress_proto(skb);
2103 
2104 	/* Protocol field should occupy 2 bytes when not compressed */
2105 	return pskb_may_pull(skb, 2);
2106 }
2107 
2108 void
ppp_input(struct ppp_channel * chan,struct sk_buff * skb)2109 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2110 {
2111 	struct channel *pch = chan->ppp;
2112 	int proto;
2113 
2114 	if (!pch) {
2115 		kfree_skb(skb);
2116 		return;
2117 	}
2118 
2119 	read_lock_bh(&pch->upl);
2120 	if (!ppp_decompress_proto(skb)) {
2121 		kfree_skb(skb);
2122 		if (pch->ppp) {
2123 			++pch->ppp->dev->stats.rx_length_errors;
2124 			ppp_receive_error(pch->ppp);
2125 		}
2126 		goto done;
2127 	}
2128 
2129 	proto = PPP_PROTO(skb);
2130 	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2131 		/* put it on the channel queue */
2132 		skb_queue_tail(&pch->file.rq, skb);
2133 		/* drop old frames if queue too long */
2134 		while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2135 		       (skb = skb_dequeue(&pch->file.rq)))
2136 			kfree_skb(skb);
2137 		wake_up_interruptible(&pch->file.rwait);
2138 	} else {
2139 		ppp_do_recv(pch->ppp, skb, pch);
2140 	}
2141 
2142 done:
2143 	read_unlock_bh(&pch->upl);
2144 }
2145 
2146 /* Put a 0-length skb in the receive queue as an error indication */
2147 void
ppp_input_error(struct ppp_channel * chan,int code)2148 ppp_input_error(struct ppp_channel *chan, int code)
2149 {
2150 	struct channel *pch = chan->ppp;
2151 	struct sk_buff *skb;
2152 
2153 	if (!pch)
2154 		return;
2155 
2156 	read_lock_bh(&pch->upl);
2157 	if (pch->ppp) {
2158 		skb = alloc_skb(0, GFP_ATOMIC);
2159 		if (skb) {
2160 			skb->len = 0;		/* probably unnecessary */
2161 			skb->cb[0] = code;
2162 			ppp_do_recv(pch->ppp, skb, pch);
2163 		}
2164 	}
2165 	read_unlock_bh(&pch->upl);
2166 }
2167 
2168 /*
2169  * We come in here to process a received frame.
2170  * The receive side of the ppp unit is locked.
2171  */
2172 static void
ppp_receive_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2173 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2174 {
2175 	/* note: a 0-length skb is used as an error indication */
2176 	if (skb->len > 0) {
2177 		skb_checksum_complete_unset(skb);
2178 #ifdef CONFIG_PPP_MULTILINK
2179 		/* XXX do channel-level decompression here */
2180 		if (PPP_PROTO(skb) == PPP_MP)
2181 			ppp_receive_mp_frame(ppp, skb, pch);
2182 		else
2183 #endif /* CONFIG_PPP_MULTILINK */
2184 			ppp_receive_nonmp_frame(ppp, skb);
2185 	} else {
2186 		kfree_skb(skb);
2187 		ppp_receive_error(ppp);
2188 	}
2189 }
2190 
2191 static void
ppp_receive_error(struct ppp * ppp)2192 ppp_receive_error(struct ppp *ppp)
2193 {
2194 	++ppp->dev->stats.rx_errors;
2195 	if (ppp->vj)
2196 		slhc_toss(ppp->vj);
2197 }
2198 
2199 static void
ppp_receive_nonmp_frame(struct ppp * ppp,struct sk_buff * skb)2200 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2201 {
2202 	struct sk_buff *ns;
2203 	int proto, len, npi;
2204 
2205 	/*
2206 	 * Decompress the frame, if compressed.
2207 	 * Note that some decompressors need to see uncompressed frames
2208 	 * that come in as well as compressed frames.
2209 	 */
2210 	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2211 	    (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2212 		skb = ppp_decompress_frame(ppp, skb);
2213 
2214 	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2215 		goto err;
2216 
2217 	/* At this point the "Protocol" field MUST be decompressed, either in
2218 	 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2219 	 */
2220 	proto = PPP_PROTO(skb);
2221 	switch (proto) {
2222 	case PPP_VJC_COMP:
2223 		/* decompress VJ compressed packets */
2224 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2225 			goto err;
2226 
2227 		if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2228 			/* copy to a new sk_buff with more tailroom */
2229 			ns = dev_alloc_skb(skb->len + 128);
2230 			if (!ns) {
2231 				netdev_err(ppp->dev, "PPP: no memory "
2232 					   "(VJ decomp)\n");
2233 				goto err;
2234 			}
2235 			skb_reserve(ns, 2);
2236 			skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2237 			consume_skb(skb);
2238 			skb = ns;
2239 		}
2240 		else
2241 			skb->ip_summed = CHECKSUM_NONE;
2242 
2243 		len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2244 		if (len <= 0) {
2245 			netdev_printk(KERN_DEBUG, ppp->dev,
2246 				      "PPP: VJ decompression error\n");
2247 			goto err;
2248 		}
2249 		len += 2;
2250 		if (len > skb->len)
2251 			skb_put(skb, len - skb->len);
2252 		else if (len < skb->len)
2253 			skb_trim(skb, len);
2254 		proto = PPP_IP;
2255 		break;
2256 
2257 	case PPP_VJC_UNCOMP:
2258 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2259 			goto err;
2260 
2261 		/* Until we fix the decompressor need to make sure
2262 		 * data portion is linear.
2263 		 */
2264 		if (!pskb_may_pull(skb, skb->len))
2265 			goto err;
2266 
2267 		if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2268 			netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2269 			goto err;
2270 		}
2271 		proto = PPP_IP;
2272 		break;
2273 
2274 	case PPP_CCP:
2275 		ppp_ccp_peek(ppp, skb, 1);
2276 		break;
2277 	}
2278 
2279 	++ppp->stats64.rx_packets;
2280 	ppp->stats64.rx_bytes += skb->len - 2;
2281 
2282 	npi = proto_to_npindex(proto);
2283 	if (npi < 0) {
2284 		/* control or unknown frame - pass it to pppd */
2285 		skb_queue_tail(&ppp->file.rq, skb);
2286 		/* limit queue length by dropping old frames */
2287 		while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2288 		       (skb = skb_dequeue(&ppp->file.rq)))
2289 			kfree_skb(skb);
2290 		/* wake up any process polling or blocking on read */
2291 		wake_up_interruptible(&ppp->file.rwait);
2292 
2293 	} else {
2294 		/* network protocol frame - give it to the kernel */
2295 
2296 #ifdef CONFIG_PPP_FILTER
2297 		/* check if the packet passes the pass and active filters */
2298 		/* the filter instructions are constructed assuming
2299 		   a four-byte PPP header on each packet */
2300 		if (ppp->pass_filter || ppp->active_filter) {
2301 			if (skb_unclone(skb, GFP_ATOMIC))
2302 				goto err;
2303 
2304 			*(u8 *)skb_push(skb, 2) = 0;
2305 			if (ppp->pass_filter &&
2306 			    BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
2307 				if (ppp->debug & 1)
2308 					netdev_printk(KERN_DEBUG, ppp->dev,
2309 						      "PPP: inbound frame "
2310 						      "not passed\n");
2311 				kfree_skb(skb);
2312 				return;
2313 			}
2314 			if (!(ppp->active_filter &&
2315 			      BPF_PROG_RUN(ppp->active_filter, skb) == 0))
2316 				ppp->last_recv = jiffies;
2317 			__skb_pull(skb, 2);
2318 		} else
2319 #endif /* CONFIG_PPP_FILTER */
2320 			ppp->last_recv = jiffies;
2321 
2322 		if ((ppp->dev->flags & IFF_UP) == 0 ||
2323 		    ppp->npmode[npi] != NPMODE_PASS) {
2324 			kfree_skb(skb);
2325 		} else {
2326 			/* chop off protocol */
2327 			skb_pull_rcsum(skb, 2);
2328 			skb->dev = ppp->dev;
2329 			skb->protocol = htons(npindex_to_ethertype[npi]);
2330 			skb_reset_mac_header(skb);
2331 			skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2332 						      dev_net(ppp->dev)));
2333 			netif_rx(skb);
2334 		}
2335 	}
2336 	return;
2337 
2338  err:
2339 	kfree_skb(skb);
2340 	ppp_receive_error(ppp);
2341 }
2342 
2343 static struct sk_buff *
ppp_decompress_frame(struct ppp * ppp,struct sk_buff * skb)2344 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2345 {
2346 	int proto = PPP_PROTO(skb);
2347 	struct sk_buff *ns;
2348 	int len;
2349 
2350 	/* Until we fix all the decompressor's need to make sure
2351 	 * data portion is linear.
2352 	 */
2353 	if (!pskb_may_pull(skb, skb->len))
2354 		goto err;
2355 
2356 	if (proto == PPP_COMP) {
2357 		int obuff_size;
2358 
2359 		switch(ppp->rcomp->compress_proto) {
2360 		case CI_MPPE:
2361 			obuff_size = ppp->mru + PPP_HDRLEN + 1;
2362 			break;
2363 		default:
2364 			obuff_size = ppp->mru + PPP_HDRLEN;
2365 			break;
2366 		}
2367 
2368 		ns = dev_alloc_skb(obuff_size);
2369 		if (!ns) {
2370 			netdev_err(ppp->dev, "ppp_decompress_frame: "
2371 				   "no memory\n");
2372 			goto err;
2373 		}
2374 		/* the decompressor still expects the A/C bytes in the hdr */
2375 		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2376 				skb->len + 2, ns->data, obuff_size);
2377 		if (len < 0) {
2378 			/* Pass the compressed frame to pppd as an
2379 			   error indication. */
2380 			if (len == DECOMP_FATALERROR)
2381 				ppp->rstate |= SC_DC_FERROR;
2382 			kfree_skb(ns);
2383 			goto err;
2384 		}
2385 
2386 		consume_skb(skb);
2387 		skb = ns;
2388 		skb_put(skb, len);
2389 		skb_pull(skb, 2);	/* pull off the A/C bytes */
2390 
2391 		/* Don't call __ppp_decompress_proto() here, but instead rely on
2392 		 * corresponding algo (mppe/bsd/deflate) to decompress it.
2393 		 */
2394 	} else {
2395 		/* Uncompressed frame - pass to decompressor so it
2396 		   can update its dictionary if necessary. */
2397 		if (ppp->rcomp->incomp)
2398 			ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2399 					   skb->len + 2);
2400 	}
2401 
2402 	return skb;
2403 
2404  err:
2405 	ppp->rstate |= SC_DC_ERROR;
2406 	ppp_receive_error(ppp);
2407 	return skb;
2408 }
2409 
2410 #ifdef CONFIG_PPP_MULTILINK
2411 /*
2412  * Receive a multilink frame.
2413  * We put it on the reconstruction queue and then pull off
2414  * as many completed frames as we can.
2415  */
2416 static void
ppp_receive_mp_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2417 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2418 {
2419 	u32 mask, seq;
2420 	struct channel *ch;
2421 	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2422 
2423 	if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2424 		goto err;		/* no good, throw it away */
2425 
2426 	/* Decode sequence number and begin/end bits */
2427 	if (ppp->flags & SC_MP_SHORTSEQ) {
2428 		seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2429 		mask = 0xfff;
2430 	} else {
2431 		seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2432 		mask = 0xffffff;
2433 	}
2434 	PPP_MP_CB(skb)->BEbits = skb->data[2];
2435 	skb_pull(skb, mphdrlen);	/* pull off PPP and MP headers */
2436 
2437 	/*
2438 	 * Do protocol ID decompression on the first fragment of each packet.
2439 	 * We have to do that here, because ppp_receive_nonmp_frame() expects
2440 	 * decompressed protocol field.
2441 	 */
2442 	if (PPP_MP_CB(skb)->BEbits & B)
2443 		__ppp_decompress_proto(skb);
2444 
2445 	/*
2446 	 * Expand sequence number to 32 bits, making it as close
2447 	 * as possible to ppp->minseq.
2448 	 */
2449 	seq |= ppp->minseq & ~mask;
2450 	if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2451 		seq += mask + 1;
2452 	else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2453 		seq -= mask + 1;	/* should never happen */
2454 	PPP_MP_CB(skb)->sequence = seq;
2455 	pch->lastseq = seq;
2456 
2457 	/*
2458 	 * If this packet comes before the next one we were expecting,
2459 	 * drop it.
2460 	 */
2461 	if (seq_before(seq, ppp->nextseq)) {
2462 		kfree_skb(skb);
2463 		++ppp->dev->stats.rx_dropped;
2464 		ppp_receive_error(ppp);
2465 		return;
2466 	}
2467 
2468 	/*
2469 	 * Reevaluate minseq, the minimum over all channels of the
2470 	 * last sequence number received on each channel.  Because of
2471 	 * the increasing sequence number rule, we know that any fragment
2472 	 * before `minseq' which hasn't arrived is never going to arrive.
2473 	 * The list of channels can't change because we have the receive
2474 	 * side of the ppp unit locked.
2475 	 */
2476 	list_for_each_entry(ch, &ppp->channels, clist) {
2477 		if (seq_before(ch->lastseq, seq))
2478 			seq = ch->lastseq;
2479 	}
2480 	if (seq_before(ppp->minseq, seq))
2481 		ppp->minseq = seq;
2482 
2483 	/* Put the fragment on the reconstruction queue */
2484 	ppp_mp_insert(ppp, skb);
2485 
2486 	/* If the queue is getting long, don't wait any longer for packets
2487 	   before the start of the queue. */
2488 	if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2489 		struct sk_buff *mskb = skb_peek(&ppp->mrq);
2490 		if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2491 			ppp->minseq = PPP_MP_CB(mskb)->sequence;
2492 	}
2493 
2494 	/* Pull completed packets off the queue and receive them. */
2495 	while ((skb = ppp_mp_reconstruct(ppp))) {
2496 		if (pskb_may_pull(skb, 2))
2497 			ppp_receive_nonmp_frame(ppp, skb);
2498 		else {
2499 			++ppp->dev->stats.rx_length_errors;
2500 			kfree_skb(skb);
2501 			ppp_receive_error(ppp);
2502 		}
2503 	}
2504 
2505 	return;
2506 
2507  err:
2508 	kfree_skb(skb);
2509 	ppp_receive_error(ppp);
2510 }
2511 
2512 /*
2513  * Insert a fragment on the MP reconstruction queue.
2514  * The queue is ordered by increasing sequence number.
2515  */
2516 static void
ppp_mp_insert(struct ppp * ppp,struct sk_buff * skb)2517 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2518 {
2519 	struct sk_buff *p;
2520 	struct sk_buff_head *list = &ppp->mrq;
2521 	u32 seq = PPP_MP_CB(skb)->sequence;
2522 
2523 	/* N.B. we don't need to lock the list lock because we have the
2524 	   ppp unit receive-side lock. */
2525 	skb_queue_walk(list, p) {
2526 		if (seq_before(seq, PPP_MP_CB(p)->sequence))
2527 			break;
2528 	}
2529 	__skb_queue_before(list, p, skb);
2530 }
2531 
2532 /*
2533  * Reconstruct a packet from the MP fragment queue.
2534  * We go through increasing sequence numbers until we find a
2535  * complete packet, or we get to the sequence number for a fragment
2536  * which hasn't arrived but might still do so.
2537  */
2538 static struct sk_buff *
ppp_mp_reconstruct(struct ppp * ppp)2539 ppp_mp_reconstruct(struct ppp *ppp)
2540 {
2541 	u32 seq = ppp->nextseq;
2542 	u32 minseq = ppp->minseq;
2543 	struct sk_buff_head *list = &ppp->mrq;
2544 	struct sk_buff *p, *tmp;
2545 	struct sk_buff *head, *tail;
2546 	struct sk_buff *skb = NULL;
2547 	int lost = 0, len = 0;
2548 
2549 	if (ppp->mrru == 0)	/* do nothing until mrru is set */
2550 		return NULL;
2551 	head = __skb_peek(list);
2552 	tail = NULL;
2553 	skb_queue_walk_safe(list, p, tmp) {
2554 	again:
2555 		if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2556 			/* this can't happen, anyway ignore the skb */
2557 			netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2558 				   "seq %u < %u\n",
2559 				   PPP_MP_CB(p)->sequence, seq);
2560 			__skb_unlink(p, list);
2561 			kfree_skb(p);
2562 			continue;
2563 		}
2564 		if (PPP_MP_CB(p)->sequence != seq) {
2565 			u32 oldseq;
2566 			/* Fragment `seq' is missing.  If it is after
2567 			   minseq, it might arrive later, so stop here. */
2568 			if (seq_after(seq, minseq))
2569 				break;
2570 			/* Fragment `seq' is lost, keep going. */
2571 			lost = 1;
2572 			oldseq = seq;
2573 			seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2574 				minseq + 1: PPP_MP_CB(p)->sequence;
2575 
2576 			if (ppp->debug & 1)
2577 				netdev_printk(KERN_DEBUG, ppp->dev,
2578 					      "lost frag %u..%u\n",
2579 					      oldseq, seq-1);
2580 
2581 			goto again;
2582 		}
2583 
2584 		/*
2585 		 * At this point we know that all the fragments from
2586 		 * ppp->nextseq to seq are either present or lost.
2587 		 * Also, there are no complete packets in the queue
2588 		 * that have no missing fragments and end before this
2589 		 * fragment.
2590 		 */
2591 
2592 		/* B bit set indicates this fragment starts a packet */
2593 		if (PPP_MP_CB(p)->BEbits & B) {
2594 			head = p;
2595 			lost = 0;
2596 			len = 0;
2597 		}
2598 
2599 		len += p->len;
2600 
2601 		/* Got a complete packet yet? */
2602 		if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2603 		    (PPP_MP_CB(head)->BEbits & B)) {
2604 			if (len > ppp->mrru + 2) {
2605 				++ppp->dev->stats.rx_length_errors;
2606 				netdev_printk(KERN_DEBUG, ppp->dev,
2607 					      "PPP: reconstructed packet"
2608 					      " is too long (%d)\n", len);
2609 			} else {
2610 				tail = p;
2611 				break;
2612 			}
2613 			ppp->nextseq = seq + 1;
2614 		}
2615 
2616 		/*
2617 		 * If this is the ending fragment of a packet,
2618 		 * and we haven't found a complete valid packet yet,
2619 		 * we can discard up to and including this fragment.
2620 		 */
2621 		if (PPP_MP_CB(p)->BEbits & E) {
2622 			struct sk_buff *tmp2;
2623 
2624 			skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2625 				if (ppp->debug & 1)
2626 					netdev_printk(KERN_DEBUG, ppp->dev,
2627 						      "discarding frag %u\n",
2628 						      PPP_MP_CB(p)->sequence);
2629 				__skb_unlink(p, list);
2630 				kfree_skb(p);
2631 			}
2632 			head = skb_peek(list);
2633 			if (!head)
2634 				break;
2635 		}
2636 		++seq;
2637 	}
2638 
2639 	/* If we have a complete packet, copy it all into one skb. */
2640 	if (tail != NULL) {
2641 		/* If we have discarded any fragments,
2642 		   signal a receive error. */
2643 		if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2644 			skb_queue_walk_safe(list, p, tmp) {
2645 				if (p == head)
2646 					break;
2647 				if (ppp->debug & 1)
2648 					netdev_printk(KERN_DEBUG, ppp->dev,
2649 						      "discarding frag %u\n",
2650 						      PPP_MP_CB(p)->sequence);
2651 				__skb_unlink(p, list);
2652 				kfree_skb(p);
2653 			}
2654 
2655 			if (ppp->debug & 1)
2656 				netdev_printk(KERN_DEBUG, ppp->dev,
2657 					      "  missed pkts %u..%u\n",
2658 					      ppp->nextseq,
2659 					      PPP_MP_CB(head)->sequence-1);
2660 			++ppp->dev->stats.rx_dropped;
2661 			ppp_receive_error(ppp);
2662 		}
2663 
2664 		skb = head;
2665 		if (head != tail) {
2666 			struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2667 			p = skb_queue_next(list, head);
2668 			__skb_unlink(skb, list);
2669 			skb_queue_walk_from_safe(list, p, tmp) {
2670 				__skb_unlink(p, list);
2671 				*fragpp = p;
2672 				p->next = NULL;
2673 				fragpp = &p->next;
2674 
2675 				skb->len += p->len;
2676 				skb->data_len += p->len;
2677 				skb->truesize += p->truesize;
2678 
2679 				if (p == tail)
2680 					break;
2681 			}
2682 		} else {
2683 			__skb_unlink(skb, list);
2684 		}
2685 
2686 		ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2687 	}
2688 
2689 	return skb;
2690 }
2691 #endif /* CONFIG_PPP_MULTILINK */
2692 
2693 /*
2694  * Channel interface.
2695  */
2696 
2697 /* Create a new, unattached ppp channel. */
ppp_register_channel(struct ppp_channel * chan)2698 int ppp_register_channel(struct ppp_channel *chan)
2699 {
2700 	return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2701 }
2702 
2703 /* Create a new, unattached ppp channel for specified net. */
ppp_register_net_channel(struct net * net,struct ppp_channel * chan)2704 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2705 {
2706 	struct channel *pch;
2707 	struct ppp_net *pn;
2708 
2709 	pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2710 	if (!pch)
2711 		return -ENOMEM;
2712 
2713 	pn = ppp_pernet(net);
2714 
2715 	pch->ppp = NULL;
2716 	pch->chan = chan;
2717 	pch->chan_net = get_net(net);
2718 	chan->ppp = pch;
2719 	init_ppp_file(&pch->file, CHANNEL);
2720 	pch->file.hdrlen = chan->hdrlen;
2721 #ifdef CONFIG_PPP_MULTILINK
2722 	pch->lastseq = -1;
2723 #endif /* CONFIG_PPP_MULTILINK */
2724 	init_rwsem(&pch->chan_sem);
2725 	spin_lock_init(&pch->downl);
2726 	rwlock_init(&pch->upl);
2727 
2728 	spin_lock_bh(&pn->all_channels_lock);
2729 	pch->file.index = ++pn->last_channel_index;
2730 	list_add(&pch->list, &pn->new_channels);
2731 	atomic_inc(&channel_count);
2732 	spin_unlock_bh(&pn->all_channels_lock);
2733 
2734 	return 0;
2735 }
2736 
2737 /*
2738  * Return the index of a channel.
2739  */
ppp_channel_index(struct ppp_channel * chan)2740 int ppp_channel_index(struct ppp_channel *chan)
2741 {
2742 	struct channel *pch = chan->ppp;
2743 
2744 	if (pch)
2745 		return pch->file.index;
2746 	return -1;
2747 }
2748 
2749 /*
2750  * Return the PPP unit number to which a channel is connected.
2751  */
ppp_unit_number(struct ppp_channel * chan)2752 int ppp_unit_number(struct ppp_channel *chan)
2753 {
2754 	struct channel *pch = chan->ppp;
2755 	int unit = -1;
2756 
2757 	if (pch) {
2758 		read_lock_bh(&pch->upl);
2759 		if (pch->ppp)
2760 			unit = pch->ppp->file.index;
2761 		read_unlock_bh(&pch->upl);
2762 	}
2763 	return unit;
2764 }
2765 
2766 /*
2767  * Return the PPP device interface name of a channel.
2768  */
ppp_dev_name(struct ppp_channel * chan)2769 char *ppp_dev_name(struct ppp_channel *chan)
2770 {
2771 	struct channel *pch = chan->ppp;
2772 	char *name = NULL;
2773 
2774 	if (pch) {
2775 		read_lock_bh(&pch->upl);
2776 		if (pch->ppp && pch->ppp->dev)
2777 			name = pch->ppp->dev->name;
2778 		read_unlock_bh(&pch->upl);
2779 	}
2780 	return name;
2781 }
2782 
2783 
2784 /*
2785  * Disconnect a channel from the generic layer.
2786  * This must be called in process context.
2787  */
2788 void
ppp_unregister_channel(struct ppp_channel * chan)2789 ppp_unregister_channel(struct ppp_channel *chan)
2790 {
2791 	struct channel *pch = chan->ppp;
2792 	struct ppp_net *pn;
2793 
2794 	if (!pch)
2795 		return;		/* should never happen */
2796 
2797 	chan->ppp = NULL;
2798 
2799 	/*
2800 	 * This ensures that we have returned from any calls into the
2801 	 * the channel's start_xmit or ioctl routine before we proceed.
2802 	 */
2803 	down_write(&pch->chan_sem);
2804 	spin_lock_bh(&pch->downl);
2805 	pch->chan = NULL;
2806 	spin_unlock_bh(&pch->downl);
2807 	up_write(&pch->chan_sem);
2808 	ppp_disconnect_channel(pch);
2809 
2810 	pn = ppp_pernet(pch->chan_net);
2811 	spin_lock_bh(&pn->all_channels_lock);
2812 	list_del(&pch->list);
2813 	spin_unlock_bh(&pn->all_channels_lock);
2814 
2815 	pch->file.dead = 1;
2816 	wake_up_interruptible(&pch->file.rwait);
2817 	if (refcount_dec_and_test(&pch->file.refcnt))
2818 		ppp_destroy_channel(pch);
2819 }
2820 
2821 /*
2822  * Callback from a channel when it can accept more to transmit.
2823  * This should be called at BH/softirq level, not interrupt level.
2824  */
2825 void
ppp_output_wakeup(struct ppp_channel * chan)2826 ppp_output_wakeup(struct ppp_channel *chan)
2827 {
2828 	struct channel *pch = chan->ppp;
2829 
2830 	if (!pch)
2831 		return;
2832 	ppp_channel_push(pch);
2833 }
2834 
2835 /*
2836  * Compression control.
2837  */
2838 
2839 /* Process the PPPIOCSCOMPRESS ioctl. */
2840 static int
ppp_set_compress(struct ppp * ppp,struct ppp_option_data * data)2841 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
2842 {
2843 	int err = -EFAULT;
2844 	struct compressor *cp, *ocomp;
2845 	void *state, *ostate;
2846 	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2847 
2848 	if (data->length > CCP_MAX_OPTION_LENGTH)
2849 		goto out;
2850 	if (copy_from_user(ccp_option, data->ptr, data->length))
2851 		goto out;
2852 
2853 	err = -EINVAL;
2854 	if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
2855 		goto out;
2856 
2857 	cp = try_then_request_module(
2858 		find_compressor(ccp_option[0]),
2859 		"ppp-compress-%d", ccp_option[0]);
2860 	if (!cp)
2861 		goto out;
2862 
2863 	err = -ENOBUFS;
2864 	if (data->transmit) {
2865 		state = cp->comp_alloc(ccp_option, data->length);
2866 		if (state) {
2867 			ppp_xmit_lock(ppp);
2868 			ppp->xstate &= ~SC_COMP_RUN;
2869 			ocomp = ppp->xcomp;
2870 			ostate = ppp->xc_state;
2871 			ppp->xcomp = cp;
2872 			ppp->xc_state = state;
2873 			ppp_xmit_unlock(ppp);
2874 			if (ostate) {
2875 				ocomp->comp_free(ostate);
2876 				module_put(ocomp->owner);
2877 			}
2878 			err = 0;
2879 		} else
2880 			module_put(cp->owner);
2881 
2882 	} else {
2883 		state = cp->decomp_alloc(ccp_option, data->length);
2884 		if (state) {
2885 			ppp_recv_lock(ppp);
2886 			ppp->rstate &= ~SC_DECOMP_RUN;
2887 			ocomp = ppp->rcomp;
2888 			ostate = ppp->rc_state;
2889 			ppp->rcomp = cp;
2890 			ppp->rc_state = state;
2891 			ppp_recv_unlock(ppp);
2892 			if (ostate) {
2893 				ocomp->decomp_free(ostate);
2894 				module_put(ocomp->owner);
2895 			}
2896 			err = 0;
2897 		} else
2898 			module_put(cp->owner);
2899 	}
2900 
2901  out:
2902 	return err;
2903 }
2904 
2905 /*
2906  * Look at a CCP packet and update our state accordingly.
2907  * We assume the caller has the xmit or recv path locked.
2908  */
2909 static void
ppp_ccp_peek(struct ppp * ppp,struct sk_buff * skb,int inbound)2910 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2911 {
2912 	unsigned char *dp;
2913 	int len;
2914 
2915 	if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2916 		return;	/* no header */
2917 	dp = skb->data + 2;
2918 
2919 	switch (CCP_CODE(dp)) {
2920 	case CCP_CONFREQ:
2921 
2922 		/* A ConfReq starts negotiation of compression
2923 		 * in one direction of transmission,
2924 		 * and hence brings it down...but which way?
2925 		 *
2926 		 * Remember:
2927 		 * A ConfReq indicates what the sender would like to receive
2928 		 */
2929 		if(inbound)
2930 			/* He is proposing what I should send */
2931 			ppp->xstate &= ~SC_COMP_RUN;
2932 		else
2933 			/* I am proposing to what he should send */
2934 			ppp->rstate &= ~SC_DECOMP_RUN;
2935 
2936 		break;
2937 
2938 	case CCP_TERMREQ:
2939 	case CCP_TERMACK:
2940 		/*
2941 		 * CCP is going down, both directions of transmission
2942 		 */
2943 		ppp->rstate &= ~SC_DECOMP_RUN;
2944 		ppp->xstate &= ~SC_COMP_RUN;
2945 		break;
2946 
2947 	case CCP_CONFACK:
2948 		if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2949 			break;
2950 		len = CCP_LENGTH(dp);
2951 		if (!pskb_may_pull(skb, len + 2))
2952 			return;		/* too short */
2953 		dp += CCP_HDRLEN;
2954 		len -= CCP_HDRLEN;
2955 		if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2956 			break;
2957 		if (inbound) {
2958 			/* we will start receiving compressed packets */
2959 			if (!ppp->rc_state)
2960 				break;
2961 			if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2962 					ppp->file.index, 0, ppp->mru, ppp->debug)) {
2963 				ppp->rstate |= SC_DECOMP_RUN;
2964 				ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2965 			}
2966 		} else {
2967 			/* we will soon start sending compressed packets */
2968 			if (!ppp->xc_state)
2969 				break;
2970 			if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2971 					ppp->file.index, 0, ppp->debug))
2972 				ppp->xstate |= SC_COMP_RUN;
2973 		}
2974 		break;
2975 
2976 	case CCP_RESETACK:
2977 		/* reset the [de]compressor */
2978 		if ((ppp->flags & SC_CCP_UP) == 0)
2979 			break;
2980 		if (inbound) {
2981 			if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2982 				ppp->rcomp->decomp_reset(ppp->rc_state);
2983 				ppp->rstate &= ~SC_DC_ERROR;
2984 			}
2985 		} else {
2986 			if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2987 				ppp->xcomp->comp_reset(ppp->xc_state);
2988 		}
2989 		break;
2990 	}
2991 }
2992 
2993 /* Free up compression resources. */
2994 static void
ppp_ccp_closed(struct ppp * ppp)2995 ppp_ccp_closed(struct ppp *ppp)
2996 {
2997 	void *xstate, *rstate;
2998 	struct compressor *xcomp, *rcomp;
2999 
3000 	ppp_lock(ppp);
3001 	ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3002 	ppp->xstate = 0;
3003 	xcomp = ppp->xcomp;
3004 	xstate = ppp->xc_state;
3005 	ppp->xc_state = NULL;
3006 	ppp->rstate = 0;
3007 	rcomp = ppp->rcomp;
3008 	rstate = ppp->rc_state;
3009 	ppp->rc_state = NULL;
3010 	ppp_unlock(ppp);
3011 
3012 	if (xstate) {
3013 		xcomp->comp_free(xstate);
3014 		module_put(xcomp->owner);
3015 	}
3016 	if (rstate) {
3017 		rcomp->decomp_free(rstate);
3018 		module_put(rcomp->owner);
3019 	}
3020 }
3021 
3022 /* List of compressors. */
3023 static LIST_HEAD(compressor_list);
3024 static DEFINE_SPINLOCK(compressor_list_lock);
3025 
3026 struct compressor_entry {
3027 	struct list_head list;
3028 	struct compressor *comp;
3029 };
3030 
3031 static struct compressor_entry *
find_comp_entry(int proto)3032 find_comp_entry(int proto)
3033 {
3034 	struct compressor_entry *ce;
3035 
3036 	list_for_each_entry(ce, &compressor_list, list) {
3037 		if (ce->comp->compress_proto == proto)
3038 			return ce;
3039 	}
3040 	return NULL;
3041 }
3042 
3043 /* Register a compressor */
3044 int
ppp_register_compressor(struct compressor * cp)3045 ppp_register_compressor(struct compressor *cp)
3046 {
3047 	struct compressor_entry *ce;
3048 	int ret;
3049 	spin_lock(&compressor_list_lock);
3050 	ret = -EEXIST;
3051 	if (find_comp_entry(cp->compress_proto))
3052 		goto out;
3053 	ret = -ENOMEM;
3054 	ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3055 	if (!ce)
3056 		goto out;
3057 	ret = 0;
3058 	ce->comp = cp;
3059 	list_add(&ce->list, &compressor_list);
3060  out:
3061 	spin_unlock(&compressor_list_lock);
3062 	return ret;
3063 }
3064 
3065 /* Unregister a compressor */
3066 void
ppp_unregister_compressor(struct compressor * cp)3067 ppp_unregister_compressor(struct compressor *cp)
3068 {
3069 	struct compressor_entry *ce;
3070 
3071 	spin_lock(&compressor_list_lock);
3072 	ce = find_comp_entry(cp->compress_proto);
3073 	if (ce && ce->comp == cp) {
3074 		list_del(&ce->list);
3075 		kfree(ce);
3076 	}
3077 	spin_unlock(&compressor_list_lock);
3078 }
3079 
3080 /* Find a compressor. */
3081 static struct compressor *
find_compressor(int type)3082 find_compressor(int type)
3083 {
3084 	struct compressor_entry *ce;
3085 	struct compressor *cp = NULL;
3086 
3087 	spin_lock(&compressor_list_lock);
3088 	ce = find_comp_entry(type);
3089 	if (ce) {
3090 		cp = ce->comp;
3091 		if (!try_module_get(cp->owner))
3092 			cp = NULL;
3093 	}
3094 	spin_unlock(&compressor_list_lock);
3095 	return cp;
3096 }
3097 
3098 /*
3099  * Miscelleneous stuff.
3100  */
3101 
3102 static void
ppp_get_stats(struct ppp * ppp,struct ppp_stats * st)3103 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3104 {
3105 	struct slcompress *vj = ppp->vj;
3106 
3107 	memset(st, 0, sizeof(*st));
3108 	st->p.ppp_ipackets = ppp->stats64.rx_packets;
3109 	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3110 	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3111 	st->p.ppp_opackets = ppp->stats64.tx_packets;
3112 	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3113 	st->p.ppp_obytes = ppp->stats64.tx_bytes;
3114 	if (!vj)
3115 		return;
3116 	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3117 	st->vj.vjs_compressed = vj->sls_o_compressed;
3118 	st->vj.vjs_searches = vj->sls_o_searches;
3119 	st->vj.vjs_misses = vj->sls_o_misses;
3120 	st->vj.vjs_errorin = vj->sls_i_error;
3121 	st->vj.vjs_tossed = vj->sls_i_tossed;
3122 	st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3123 	st->vj.vjs_compressedin = vj->sls_i_compressed;
3124 }
3125 
3126 /*
3127  * Stuff for handling the lists of ppp units and channels
3128  * and for initialization.
3129  */
3130 
3131 /*
3132  * Create a new ppp interface unit.  Fails if it can't allocate memory
3133  * or if there is already a unit with the requested number.
3134  * unit == -1 means allocate a new number.
3135  */
ppp_create_interface(struct net * net,struct file * file,int * unit)3136 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3137 {
3138 	struct ppp_config conf = {
3139 		.file = file,
3140 		.unit = *unit,
3141 		.ifname_is_set = false,
3142 	};
3143 	struct net_device *dev;
3144 	struct ppp *ppp;
3145 	int err;
3146 
3147 	dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3148 	if (!dev) {
3149 		err = -ENOMEM;
3150 		goto err;
3151 	}
3152 	dev_net_set(dev, net);
3153 	dev->rtnl_link_ops = &ppp_link_ops;
3154 
3155 	rtnl_lock();
3156 
3157 	err = ppp_dev_configure(net, dev, &conf);
3158 	if (err < 0)
3159 		goto err_dev;
3160 	ppp = netdev_priv(dev);
3161 	*unit = ppp->file.index;
3162 
3163 	rtnl_unlock();
3164 
3165 	return 0;
3166 
3167 err_dev:
3168 	rtnl_unlock();
3169 	free_netdev(dev);
3170 err:
3171 	return err;
3172 }
3173 
3174 /*
3175  * Initialize a ppp_file structure.
3176  */
3177 static void
init_ppp_file(struct ppp_file * pf,int kind)3178 init_ppp_file(struct ppp_file *pf, int kind)
3179 {
3180 	pf->kind = kind;
3181 	skb_queue_head_init(&pf->xq);
3182 	skb_queue_head_init(&pf->rq);
3183 	refcount_set(&pf->refcnt, 1);
3184 	init_waitqueue_head(&pf->rwait);
3185 }
3186 
3187 /*
3188  * Free the memory used by a ppp unit.  This is only called once
3189  * there are no channels connected to the unit and no file structs
3190  * that reference the unit.
3191  */
ppp_destroy_interface(struct ppp * ppp)3192 static void ppp_destroy_interface(struct ppp *ppp)
3193 {
3194 	atomic_dec(&ppp_unit_count);
3195 
3196 	if (!ppp->file.dead || ppp->n_channels) {
3197 		/* "can't happen" */
3198 		netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3199 			   "but dead=%d n_channels=%d !\n",
3200 			   ppp, ppp->file.dead, ppp->n_channels);
3201 		return;
3202 	}
3203 
3204 	ppp_ccp_closed(ppp);
3205 	if (ppp->vj) {
3206 		slhc_free(ppp->vj);
3207 		ppp->vj = NULL;
3208 	}
3209 	skb_queue_purge(&ppp->file.xq);
3210 	skb_queue_purge(&ppp->file.rq);
3211 #ifdef CONFIG_PPP_MULTILINK
3212 	skb_queue_purge(&ppp->mrq);
3213 #endif /* CONFIG_PPP_MULTILINK */
3214 #ifdef CONFIG_PPP_FILTER
3215 	if (ppp->pass_filter) {
3216 		bpf_prog_destroy(ppp->pass_filter);
3217 		ppp->pass_filter = NULL;
3218 	}
3219 
3220 	if (ppp->active_filter) {
3221 		bpf_prog_destroy(ppp->active_filter);
3222 		ppp->active_filter = NULL;
3223 	}
3224 #endif /* CONFIG_PPP_FILTER */
3225 
3226 	kfree_skb(ppp->xmit_pending);
3227 	free_percpu(ppp->xmit_recursion);
3228 
3229 	free_netdev(ppp->dev);
3230 }
3231 
3232 /*
3233  * Locate an existing ppp unit.
3234  * The caller should have locked the all_ppp_mutex.
3235  */
3236 static struct ppp *
ppp_find_unit(struct ppp_net * pn,int unit)3237 ppp_find_unit(struct ppp_net *pn, int unit)
3238 {
3239 	return unit_find(&pn->units_idr, unit);
3240 }
3241 
3242 /*
3243  * Locate an existing ppp channel.
3244  * The caller should have locked the all_channels_lock.
3245  * First we look in the new_channels list, then in the
3246  * all_channels list.  If found in the new_channels list,
3247  * we move it to the all_channels list.  This is for speed
3248  * when we have a lot of channels in use.
3249  */
3250 static struct channel *
ppp_find_channel(struct ppp_net * pn,int unit)3251 ppp_find_channel(struct ppp_net *pn, int unit)
3252 {
3253 	struct channel *pch;
3254 
3255 	list_for_each_entry(pch, &pn->new_channels, list) {
3256 		if (pch->file.index == unit) {
3257 			list_move(&pch->list, &pn->all_channels);
3258 			return pch;
3259 		}
3260 	}
3261 
3262 	list_for_each_entry(pch, &pn->all_channels, list) {
3263 		if (pch->file.index == unit)
3264 			return pch;
3265 	}
3266 
3267 	return NULL;
3268 }
3269 
3270 /*
3271  * Connect a PPP channel to a PPP interface unit.
3272  */
3273 static int
ppp_connect_channel(struct channel * pch,int unit)3274 ppp_connect_channel(struct channel *pch, int unit)
3275 {
3276 	struct ppp *ppp;
3277 	struct ppp_net *pn;
3278 	int ret = -ENXIO;
3279 	int hdrlen;
3280 
3281 	pn = ppp_pernet(pch->chan_net);
3282 
3283 	mutex_lock(&pn->all_ppp_mutex);
3284 	ppp = ppp_find_unit(pn, unit);
3285 	if (!ppp)
3286 		goto out;
3287 	write_lock_bh(&pch->upl);
3288 	ret = -EINVAL;
3289 	if (pch->ppp)
3290 		goto outl;
3291 
3292 	ppp_lock(ppp);
3293 	spin_lock_bh(&pch->downl);
3294 	if (!pch->chan) {
3295 		/* Don't connect unregistered channels */
3296 		spin_unlock_bh(&pch->downl);
3297 		ppp_unlock(ppp);
3298 		ret = -ENOTCONN;
3299 		goto outl;
3300 	}
3301 	spin_unlock_bh(&pch->downl);
3302 	if (pch->file.hdrlen > ppp->file.hdrlen)
3303 		ppp->file.hdrlen = pch->file.hdrlen;
3304 	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
3305 	if (hdrlen > ppp->dev->hard_header_len)
3306 		ppp->dev->hard_header_len = hdrlen;
3307 	list_add_tail(&pch->clist, &ppp->channels);
3308 	++ppp->n_channels;
3309 	pch->ppp = ppp;
3310 	refcount_inc(&ppp->file.refcnt);
3311 	ppp_unlock(ppp);
3312 	ret = 0;
3313 
3314  outl:
3315 	write_unlock_bh(&pch->upl);
3316  out:
3317 	mutex_unlock(&pn->all_ppp_mutex);
3318 	return ret;
3319 }
3320 
3321 /*
3322  * Disconnect a channel from its ppp unit.
3323  */
3324 static int
ppp_disconnect_channel(struct channel * pch)3325 ppp_disconnect_channel(struct channel *pch)
3326 {
3327 	struct ppp *ppp;
3328 	int err = -EINVAL;
3329 
3330 	write_lock_bh(&pch->upl);
3331 	ppp = pch->ppp;
3332 	pch->ppp = NULL;
3333 	write_unlock_bh(&pch->upl);
3334 	if (ppp) {
3335 		/* remove it from the ppp unit's list */
3336 		ppp_lock(ppp);
3337 		list_del(&pch->clist);
3338 		if (--ppp->n_channels == 0)
3339 			wake_up_interruptible(&ppp->file.rwait);
3340 		ppp_unlock(ppp);
3341 		if (refcount_dec_and_test(&ppp->file.refcnt))
3342 			ppp_destroy_interface(ppp);
3343 		err = 0;
3344 	}
3345 	return err;
3346 }
3347 
3348 /*
3349  * Free up the resources used by a ppp channel.
3350  */
ppp_destroy_channel(struct channel * pch)3351 static void ppp_destroy_channel(struct channel *pch)
3352 {
3353 	put_net(pch->chan_net);
3354 	pch->chan_net = NULL;
3355 
3356 	atomic_dec(&channel_count);
3357 
3358 	if (!pch->file.dead) {
3359 		/* "can't happen" */
3360 		pr_err("ppp: destroying undead channel %p !\n", pch);
3361 		return;
3362 	}
3363 	skb_queue_purge(&pch->file.xq);
3364 	skb_queue_purge(&pch->file.rq);
3365 	kfree(pch);
3366 }
3367 
ppp_cleanup(void)3368 static void __exit ppp_cleanup(void)
3369 {
3370 	/* should never happen */
3371 	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3372 		pr_err("PPP: removing module but units remain!\n");
3373 	rtnl_link_unregister(&ppp_link_ops);
3374 	unregister_chrdev(PPP_MAJOR, "ppp");
3375 	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3376 	class_destroy(ppp_class);
3377 	unregister_pernet_device(&ppp_net_ops);
3378 }
3379 
3380 /*
3381  * Units handling. Caller must protect concurrent access
3382  * by holding all_ppp_mutex
3383  */
3384 
3385 /* associate pointer with specified number */
unit_set(struct idr * p,void * ptr,int n)3386 static int unit_set(struct idr *p, void *ptr, int n)
3387 {
3388 	int unit;
3389 
3390 	unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3391 	if (unit == -ENOSPC)
3392 		unit = -EINVAL;
3393 	return unit;
3394 }
3395 
3396 /* get new free unit number and associate pointer with it */
unit_get(struct idr * p,void * ptr,int min)3397 static int unit_get(struct idr *p, void *ptr, int min)
3398 {
3399 	return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3400 }
3401 
3402 /* put unit number back to a pool */
unit_put(struct idr * p,int n)3403 static void unit_put(struct idr *p, int n)
3404 {
3405 	idr_remove(p, n);
3406 }
3407 
3408 /* get pointer associated with the number */
unit_find(struct idr * p,int n)3409 static void *unit_find(struct idr *p, int n)
3410 {
3411 	return idr_find(p, n);
3412 }
3413 
3414 /* Module/initialization stuff */
3415 
3416 module_init(ppp_init);
3417 module_exit(ppp_cleanup);
3418 
3419 EXPORT_SYMBOL(ppp_register_net_channel);
3420 EXPORT_SYMBOL(ppp_register_channel);
3421 EXPORT_SYMBOL(ppp_unregister_channel);
3422 EXPORT_SYMBOL(ppp_channel_index);
3423 EXPORT_SYMBOL(ppp_unit_number);
3424 EXPORT_SYMBOL(ppp_dev_name);
3425 EXPORT_SYMBOL(ppp_input);
3426 EXPORT_SYMBOL(ppp_input_error);
3427 EXPORT_SYMBOL(ppp_output_wakeup);
3428 EXPORT_SYMBOL(ppp_register_compressor);
3429 EXPORT_SYMBOL(ppp_unregister_compressor);
3430 MODULE_LICENSE("GPL");
3431 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3432 MODULE_ALIAS_RTNL_LINK("ppp");
3433 MODULE_ALIAS("devname:ppp");
3434