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 	netns_tracker	ns_tracker;
179 	struct list_head clist;		/* link in list of channels per unit */
180 	rwlock_t	upl;		/* protects `ppp' and 'bridge' */
181 	struct channel __rcu *bridge;	/* "bridged" ppp channel */
182 #ifdef CONFIG_PPP_MULTILINK
183 	u8		avail;		/* flag used in multilink stuff */
184 	u8		had_frag;	/* >= 1 fragments have been sent */
185 	u32		lastseq;	/* MP: last sequence # received */
186 	int		speed;		/* speed of the corresponding ppp channel*/
187 #endif /* CONFIG_PPP_MULTILINK */
188 };
189 
190 struct ppp_config {
191 	struct file *file;
192 	s32 unit;
193 	bool ifname_is_set;
194 };
195 
196 /*
197  * SMP locking issues:
198  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
199  * list and the ppp.n_channels field, you need to take both locks
200  * before you modify them.
201  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
202  * channel.downl.
203  */
204 
205 static DEFINE_MUTEX(ppp_mutex);
206 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
207 static atomic_t channel_count = ATOMIC_INIT(0);
208 
209 /* per-net private data for this module */
210 static unsigned int ppp_net_id __read_mostly;
211 struct ppp_net {
212 	/* units to ppp mapping */
213 	struct idr units_idr;
214 
215 	/*
216 	 * all_ppp_mutex protects the units_idr mapping.
217 	 * It also ensures that finding a ppp unit in the units_idr
218 	 * map and updating its file.refcnt field is atomic.
219 	 */
220 	struct mutex all_ppp_mutex;
221 
222 	/* channels */
223 	struct list_head all_channels;
224 	struct list_head new_channels;
225 	int last_channel_index;
226 
227 	/*
228 	 * all_channels_lock protects all_channels and
229 	 * last_channel_index, and the atomicity of find
230 	 * a channel and updating its file.refcnt field.
231 	 */
232 	spinlock_t all_channels_lock;
233 };
234 
235 /* Get the PPP protocol number from a skb */
236 #define PPP_PROTO(skb)	get_unaligned_be16((skb)->data)
237 
238 /* We limit the length of ppp->file.rq to this (arbitrary) value */
239 #define PPP_MAX_RQLEN	32
240 
241 /*
242  * Maximum number of multilink fragments queued up.
243  * This has to be large enough to cope with the maximum latency of
244  * the slowest channel relative to the others.  Strictly it should
245  * depend on the number of channels and their characteristics.
246  */
247 #define PPP_MP_MAX_QLEN	128
248 
249 /* Multilink header bits. */
250 #define B	0x80		/* this fragment begins a packet */
251 #define E	0x40		/* this fragment ends a packet */
252 
253 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
254 #define seq_before(a, b)	((s32)((a) - (b)) < 0)
255 #define seq_after(a, b)		((s32)((a) - (b)) > 0)
256 
257 /* Prototypes. */
258 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
259 			struct file *file, unsigned int cmd, unsigned long arg);
260 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
261 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
262 static void ppp_push(struct ppp *ppp);
263 static void ppp_channel_push(struct channel *pch);
264 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
265 			      struct channel *pch);
266 static void ppp_receive_error(struct ppp *ppp);
267 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
268 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
269 					    struct sk_buff *skb);
270 #ifdef CONFIG_PPP_MULTILINK
271 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
272 				struct channel *pch);
273 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
274 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
275 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
276 #endif /* CONFIG_PPP_MULTILINK */
277 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
278 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
279 static void ppp_ccp_closed(struct ppp *ppp);
280 static struct compressor *find_compressor(int type);
281 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
282 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
283 static void init_ppp_file(struct ppp_file *pf, int kind);
284 static void ppp_destroy_interface(struct ppp *ppp);
285 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
286 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
287 static int ppp_connect_channel(struct channel *pch, int unit);
288 static int ppp_disconnect_channel(struct channel *pch);
289 static void ppp_destroy_channel(struct channel *pch);
290 static int unit_get(struct idr *p, void *ptr, int min);
291 static int unit_set(struct idr *p, void *ptr, int n);
292 static void unit_put(struct idr *p, int n);
293 static void *unit_find(struct idr *p, int n);
294 static void ppp_setup(struct net_device *dev);
295 
296 static const struct net_device_ops ppp_netdev_ops;
297 
298 static struct class *ppp_class;
299 
300 /* per net-namespace data */
ppp_pernet(struct net * net)301 static inline struct ppp_net *ppp_pernet(struct net *net)
302 {
303 	return net_generic(net, ppp_net_id);
304 }
305 
306 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)307 static inline int proto_to_npindex(int proto)
308 {
309 	switch (proto) {
310 	case PPP_IP:
311 		return NP_IP;
312 	case PPP_IPV6:
313 		return NP_IPV6;
314 	case PPP_IPX:
315 		return NP_IPX;
316 	case PPP_AT:
317 		return NP_AT;
318 	case PPP_MPLS_UC:
319 		return NP_MPLS_UC;
320 	case PPP_MPLS_MC:
321 		return NP_MPLS_MC;
322 	}
323 	return -EINVAL;
324 }
325 
326 /* Translates an NP index into a PPP protocol number */
327 static const int npindex_to_proto[NUM_NP] = {
328 	PPP_IP,
329 	PPP_IPV6,
330 	PPP_IPX,
331 	PPP_AT,
332 	PPP_MPLS_UC,
333 	PPP_MPLS_MC,
334 };
335 
336 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)337 static inline int ethertype_to_npindex(int ethertype)
338 {
339 	switch (ethertype) {
340 	case ETH_P_IP:
341 		return NP_IP;
342 	case ETH_P_IPV6:
343 		return NP_IPV6;
344 	case ETH_P_IPX:
345 		return NP_IPX;
346 	case ETH_P_PPPTALK:
347 	case ETH_P_ATALK:
348 		return NP_AT;
349 	case ETH_P_MPLS_UC:
350 		return NP_MPLS_UC;
351 	case ETH_P_MPLS_MC:
352 		return NP_MPLS_MC;
353 	}
354 	return -1;
355 }
356 
357 /* Translates an NP index into an ethertype */
358 static const int npindex_to_ethertype[NUM_NP] = {
359 	ETH_P_IP,
360 	ETH_P_IPV6,
361 	ETH_P_IPX,
362 	ETH_P_PPPTALK,
363 	ETH_P_MPLS_UC,
364 	ETH_P_MPLS_MC,
365 };
366 
367 /*
368  * Locking shorthand.
369  */
370 #define ppp_xmit_lock(ppp)	spin_lock_bh(&(ppp)->wlock)
371 #define ppp_xmit_unlock(ppp)	spin_unlock_bh(&(ppp)->wlock)
372 #define ppp_recv_lock(ppp)	spin_lock_bh(&(ppp)->rlock)
373 #define ppp_recv_unlock(ppp)	spin_unlock_bh(&(ppp)->rlock)
374 #define ppp_lock(ppp)		do { ppp_xmit_lock(ppp); \
375 				     ppp_recv_lock(ppp); } while (0)
376 #define ppp_unlock(ppp)		do { ppp_recv_unlock(ppp); \
377 				     ppp_xmit_unlock(ppp); } while (0)
378 
379 /*
380  * /dev/ppp device routines.
381  * The /dev/ppp device is used by pppd to control the ppp unit.
382  * It supports the read, write, ioctl and poll functions.
383  * Open instances of /dev/ppp can be in one of three states:
384  * unattached, attached to a ppp unit, or attached to a ppp channel.
385  */
ppp_open(struct inode * inode,struct file * file)386 static int ppp_open(struct inode *inode, struct file *file)
387 {
388 	/*
389 	 * This could (should?) be enforced by the permissions on /dev/ppp.
390 	 */
391 	if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
392 		return -EPERM;
393 	return 0;
394 }
395 
ppp_release(struct inode * unused,struct file * file)396 static int ppp_release(struct inode *unused, struct file *file)
397 {
398 	struct ppp_file *pf = file->private_data;
399 	struct ppp *ppp;
400 
401 	if (pf) {
402 		file->private_data = NULL;
403 		if (pf->kind == INTERFACE) {
404 			ppp = PF_TO_PPP(pf);
405 			rtnl_lock();
406 			if (file == ppp->owner)
407 				unregister_netdevice(ppp->dev);
408 			rtnl_unlock();
409 		}
410 		if (refcount_dec_and_test(&pf->refcnt)) {
411 			switch (pf->kind) {
412 			case INTERFACE:
413 				ppp_destroy_interface(PF_TO_PPP(pf));
414 				break;
415 			case CHANNEL:
416 				ppp_destroy_channel(PF_TO_CHANNEL(pf));
417 				break;
418 			}
419 		}
420 	}
421 	return 0;
422 }
423 
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)424 static ssize_t ppp_read(struct file *file, char __user *buf,
425 			size_t count, loff_t *ppos)
426 {
427 	struct ppp_file *pf = file->private_data;
428 	DECLARE_WAITQUEUE(wait, current);
429 	ssize_t ret;
430 	struct sk_buff *skb = NULL;
431 	struct iovec iov;
432 	struct iov_iter to;
433 
434 	ret = count;
435 
436 	if (!pf)
437 		return -ENXIO;
438 	add_wait_queue(&pf->rwait, &wait);
439 	for (;;) {
440 		set_current_state(TASK_INTERRUPTIBLE);
441 		skb = skb_dequeue(&pf->rq);
442 		if (skb)
443 			break;
444 		ret = 0;
445 		if (pf->dead)
446 			break;
447 		if (pf->kind == INTERFACE) {
448 			/*
449 			 * Return 0 (EOF) on an interface that has no
450 			 * channels connected, unless it is looping
451 			 * network traffic (demand mode).
452 			 */
453 			struct ppp *ppp = PF_TO_PPP(pf);
454 
455 			ppp_recv_lock(ppp);
456 			if (ppp->n_channels == 0 &&
457 			    (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
458 				ppp_recv_unlock(ppp);
459 				break;
460 			}
461 			ppp_recv_unlock(ppp);
462 		}
463 		ret = -EAGAIN;
464 		if (file->f_flags & O_NONBLOCK)
465 			break;
466 		ret = -ERESTARTSYS;
467 		if (signal_pending(current))
468 			break;
469 		schedule();
470 	}
471 	set_current_state(TASK_RUNNING);
472 	remove_wait_queue(&pf->rwait, &wait);
473 
474 	if (!skb)
475 		goto out;
476 
477 	ret = -EOVERFLOW;
478 	if (skb->len > count)
479 		goto outf;
480 	ret = -EFAULT;
481 	iov.iov_base = buf;
482 	iov.iov_len = count;
483 	iov_iter_init(&to, READ, &iov, 1, count);
484 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
485 		goto outf;
486 	ret = skb->len;
487 
488  outf:
489 	kfree_skb(skb);
490  out:
491 	return ret;
492 }
493 
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)494 static ssize_t ppp_write(struct file *file, const char __user *buf,
495 			 size_t count, loff_t *ppos)
496 {
497 	struct ppp_file *pf = file->private_data;
498 	struct sk_buff *skb;
499 	ssize_t ret;
500 
501 	if (!pf)
502 		return -ENXIO;
503 	/* All PPP packets should start with the 2-byte protocol */
504 	if (count < PPP_PROTO_LEN)
505 		return -EINVAL;
506 	ret = -ENOMEM;
507 	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
508 	if (!skb)
509 		goto out;
510 	skb_reserve(skb, pf->hdrlen);
511 	ret = -EFAULT;
512 	if (copy_from_user(skb_put(skb, count), buf, count)) {
513 		kfree_skb(skb);
514 		goto out;
515 	}
516 
517 	switch (pf->kind) {
518 	case INTERFACE:
519 		ppp_xmit_process(PF_TO_PPP(pf), skb);
520 		break;
521 	case CHANNEL:
522 		skb_queue_tail(&pf->xq, skb);
523 		ppp_channel_push(PF_TO_CHANNEL(pf));
524 		break;
525 	}
526 
527 	ret = count;
528 
529  out:
530 	return ret;
531 }
532 
533 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)534 static __poll_t ppp_poll(struct file *file, poll_table *wait)
535 {
536 	struct ppp_file *pf = file->private_data;
537 	__poll_t mask;
538 
539 	if (!pf)
540 		return 0;
541 	poll_wait(file, &pf->rwait, wait);
542 	mask = EPOLLOUT | EPOLLWRNORM;
543 	if (skb_peek(&pf->rq))
544 		mask |= EPOLLIN | EPOLLRDNORM;
545 	if (pf->dead)
546 		mask |= EPOLLHUP;
547 	else if (pf->kind == INTERFACE) {
548 		/* see comment in ppp_read */
549 		struct ppp *ppp = PF_TO_PPP(pf);
550 
551 		ppp_recv_lock(ppp);
552 		if (ppp->n_channels == 0 &&
553 		    (ppp->flags & SC_LOOP_TRAFFIC) == 0)
554 			mask |= EPOLLIN | EPOLLRDNORM;
555 		ppp_recv_unlock(ppp);
556 	}
557 
558 	return mask;
559 }
560 
561 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)562 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
563 {
564 	struct sock_fprog_kern fprog;
565 	struct bpf_prog *res = NULL;
566 	int err;
567 
568 	if (!uprog->len)
569 		return NULL;
570 
571 	/* uprog->len is unsigned short, so no overflow here */
572 	fprog.len = uprog->len;
573 	fprog.filter = memdup_user(uprog->filter,
574 				   uprog->len * sizeof(struct sock_filter));
575 	if (IS_ERR(fprog.filter))
576 		return ERR_CAST(fprog.filter);
577 
578 	err = bpf_prog_create(&res, &fprog);
579 	kfree(fprog.filter);
580 
581 	return err ? ERR_PTR(err) : res;
582 }
583 
ppp_get_filter(struct sock_fprog __user * p)584 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
585 {
586 	struct sock_fprog uprog;
587 
588 	if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
589 		return ERR_PTR(-EFAULT);
590 	return get_filter(&uprog);
591 }
592 
593 #ifdef CONFIG_COMPAT
594 struct sock_fprog32 {
595 	unsigned short len;
596 	compat_caddr_t filter;
597 };
598 
599 #define PPPIOCSPASS32		_IOW('t', 71, struct sock_fprog32)
600 #define PPPIOCSACTIVE32		_IOW('t', 70, struct sock_fprog32)
601 
compat_ppp_get_filter(struct sock_fprog32 __user * p)602 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
603 {
604 	struct sock_fprog32 uprog32;
605 	struct sock_fprog uprog;
606 
607 	if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
608 		return ERR_PTR(-EFAULT);
609 	uprog.len = uprog32.len;
610 	uprog.filter = compat_ptr(uprog32.filter);
611 	return get_filter(&uprog);
612 }
613 #endif
614 #endif
615 
616 /* Bridge one PPP channel to another.
617  * When two channels are bridged, ppp_input on one channel is redirected to
618  * the other's ops->start_xmit handler.
619  * In order to safely bridge channels we must reject channels which are already
620  * part of a bridge instance, or which form part of an existing unit.
621  * Once successfully bridged, each channel holds a reference on the other
622  * to prevent it being freed while the bridge is extant.
623  */
ppp_bridge_channels(struct channel * pch,struct channel * pchb)624 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
625 {
626 	write_lock_bh(&pch->upl);
627 	if (pch->ppp ||
628 	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
629 		write_unlock_bh(&pch->upl);
630 		return -EALREADY;
631 	}
632 	refcount_inc(&pchb->file.refcnt);
633 	rcu_assign_pointer(pch->bridge, pchb);
634 	write_unlock_bh(&pch->upl);
635 
636 	write_lock_bh(&pchb->upl);
637 	if (pchb->ppp ||
638 	    rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
639 		write_unlock_bh(&pchb->upl);
640 		goto err_unset;
641 	}
642 	refcount_inc(&pch->file.refcnt);
643 	rcu_assign_pointer(pchb->bridge, pch);
644 	write_unlock_bh(&pchb->upl);
645 
646 	return 0;
647 
648 err_unset:
649 	write_lock_bh(&pch->upl);
650 	/* Re-read pch->bridge with upl held in case it was modified concurrently */
651 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
652 	RCU_INIT_POINTER(pch->bridge, NULL);
653 	write_unlock_bh(&pch->upl);
654 	synchronize_rcu();
655 
656 	if (pchb)
657 		if (refcount_dec_and_test(&pchb->file.refcnt))
658 			ppp_destroy_channel(pchb);
659 
660 	return -EALREADY;
661 }
662 
ppp_unbridge_channels(struct channel * pch)663 static int ppp_unbridge_channels(struct channel *pch)
664 {
665 	struct channel *pchb, *pchbb;
666 
667 	write_lock_bh(&pch->upl);
668 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
669 	if (!pchb) {
670 		write_unlock_bh(&pch->upl);
671 		return -EINVAL;
672 	}
673 	RCU_INIT_POINTER(pch->bridge, NULL);
674 	write_unlock_bh(&pch->upl);
675 
676 	/* Only modify pchb if phcb->bridge points back to pch.
677 	 * If not, it implies that there has been a race unbridging (and possibly
678 	 * even rebridging) pchb.  We should leave pchb alone to avoid either a
679 	 * refcount underflow, or breaking another established bridge instance.
680 	 */
681 	write_lock_bh(&pchb->upl);
682 	pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
683 	if (pchbb == pch)
684 		RCU_INIT_POINTER(pchb->bridge, NULL);
685 	write_unlock_bh(&pchb->upl);
686 
687 	synchronize_rcu();
688 
689 	if (pchbb == pch)
690 		if (refcount_dec_and_test(&pch->file.refcnt))
691 			ppp_destroy_channel(pch);
692 
693 	if (refcount_dec_and_test(&pchb->file.refcnt))
694 		ppp_destroy_channel(pchb);
695 
696 	return 0;
697 }
698 
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)699 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
700 {
701 	struct ppp_file *pf;
702 	struct ppp *ppp;
703 	int err = -EFAULT, val, val2, i;
704 	struct ppp_idle32 idle32;
705 	struct ppp_idle64 idle64;
706 	struct npioctl npi;
707 	int unit, cflags;
708 	struct slcompress *vj;
709 	void __user *argp = (void __user *)arg;
710 	int __user *p = argp;
711 
712 	mutex_lock(&ppp_mutex);
713 
714 	pf = file->private_data;
715 	if (!pf) {
716 		err = ppp_unattached_ioctl(current->nsproxy->net_ns,
717 					   pf, file, cmd, arg);
718 		goto out;
719 	}
720 
721 	if (cmd == PPPIOCDETACH) {
722 		/*
723 		 * PPPIOCDETACH is no longer supported as it was heavily broken,
724 		 * and is only known to have been used by pppd older than
725 		 * ppp-2.4.2 (released November 2003).
726 		 */
727 		pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
728 			     current->comm, current->pid);
729 		err = -EINVAL;
730 		goto out;
731 	}
732 
733 	if (pf->kind == CHANNEL) {
734 		struct channel *pch, *pchb;
735 		struct ppp_channel *chan;
736 		struct ppp_net *pn;
737 
738 		pch = PF_TO_CHANNEL(pf);
739 
740 		switch (cmd) {
741 		case PPPIOCCONNECT:
742 			if (get_user(unit, p))
743 				break;
744 			err = ppp_connect_channel(pch, unit);
745 			break;
746 
747 		case PPPIOCDISCONN:
748 			err = ppp_disconnect_channel(pch);
749 			break;
750 
751 		case PPPIOCBRIDGECHAN:
752 			if (get_user(unit, p))
753 				break;
754 			err = -ENXIO;
755 			pn = ppp_pernet(current->nsproxy->net_ns);
756 			spin_lock_bh(&pn->all_channels_lock);
757 			pchb = ppp_find_channel(pn, unit);
758 			/* Hold a reference to prevent pchb being freed while
759 			 * we establish the bridge.
760 			 */
761 			if (pchb)
762 				refcount_inc(&pchb->file.refcnt);
763 			spin_unlock_bh(&pn->all_channels_lock);
764 			if (!pchb)
765 				break;
766 			err = ppp_bridge_channels(pch, pchb);
767 			/* Drop earlier refcount now bridge establishment is complete */
768 			if (refcount_dec_and_test(&pchb->file.refcnt))
769 				ppp_destroy_channel(pchb);
770 			break;
771 
772 		case PPPIOCUNBRIDGECHAN:
773 			err = ppp_unbridge_channels(pch);
774 			break;
775 
776 		default:
777 			down_read(&pch->chan_sem);
778 			chan = pch->chan;
779 			err = -ENOTTY;
780 			if (chan && chan->ops->ioctl)
781 				err = chan->ops->ioctl(chan, cmd, arg);
782 			up_read(&pch->chan_sem);
783 		}
784 		goto out;
785 	}
786 
787 	if (pf->kind != INTERFACE) {
788 		/* can't happen */
789 		pr_err("PPP: not interface or channel??\n");
790 		err = -EINVAL;
791 		goto out;
792 	}
793 
794 	ppp = PF_TO_PPP(pf);
795 	switch (cmd) {
796 	case PPPIOCSMRU:
797 		if (get_user(val, p))
798 			break;
799 		ppp->mru = val;
800 		err = 0;
801 		break;
802 
803 	case PPPIOCSFLAGS:
804 		if (get_user(val, p))
805 			break;
806 		ppp_lock(ppp);
807 		cflags = ppp->flags & ~val;
808 #ifdef CONFIG_PPP_MULTILINK
809 		if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
810 			ppp->nextseq = 0;
811 #endif
812 		ppp->flags = val & SC_FLAG_BITS;
813 		ppp_unlock(ppp);
814 		if (cflags & SC_CCP_OPEN)
815 			ppp_ccp_closed(ppp);
816 		err = 0;
817 		break;
818 
819 	case PPPIOCGFLAGS:
820 		val = ppp->flags | ppp->xstate | ppp->rstate;
821 		if (put_user(val, p))
822 			break;
823 		err = 0;
824 		break;
825 
826 	case PPPIOCSCOMPRESS:
827 	{
828 		struct ppp_option_data data;
829 		if (copy_from_user(&data, argp, sizeof(data)))
830 			err = -EFAULT;
831 		else
832 			err = ppp_set_compress(ppp, &data);
833 		break;
834 	}
835 	case PPPIOCGUNIT:
836 		if (put_user(ppp->file.index, p))
837 			break;
838 		err = 0;
839 		break;
840 
841 	case PPPIOCSDEBUG:
842 		if (get_user(val, p))
843 			break;
844 		ppp->debug = val;
845 		err = 0;
846 		break;
847 
848 	case PPPIOCGDEBUG:
849 		if (put_user(ppp->debug, p))
850 			break;
851 		err = 0;
852 		break;
853 
854 	case PPPIOCGIDLE32:
855                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
856                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
857                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
858 			break;
859 		err = 0;
860 		break;
861 
862 	case PPPIOCGIDLE64:
863 		idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
864 		idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
865 		if (copy_to_user(argp, &idle64, sizeof(idle64)))
866 			break;
867 		err = 0;
868 		break;
869 
870 	case PPPIOCSMAXCID:
871 		if (get_user(val, p))
872 			break;
873 		val2 = 15;
874 		if ((val >> 16) != 0) {
875 			val2 = val >> 16;
876 			val &= 0xffff;
877 		}
878 		vj = slhc_init(val2+1, val+1);
879 		if (IS_ERR(vj)) {
880 			err = PTR_ERR(vj);
881 			break;
882 		}
883 		ppp_lock(ppp);
884 		if (ppp->vj)
885 			slhc_free(ppp->vj);
886 		ppp->vj = vj;
887 		ppp_unlock(ppp);
888 		err = 0;
889 		break;
890 
891 	case PPPIOCGNPMODE:
892 	case PPPIOCSNPMODE:
893 		if (copy_from_user(&npi, argp, sizeof(npi)))
894 			break;
895 		err = proto_to_npindex(npi.protocol);
896 		if (err < 0)
897 			break;
898 		i = err;
899 		if (cmd == PPPIOCGNPMODE) {
900 			err = -EFAULT;
901 			npi.mode = ppp->npmode[i];
902 			if (copy_to_user(argp, &npi, sizeof(npi)))
903 				break;
904 		} else {
905 			ppp->npmode[i] = npi.mode;
906 			/* we may be able to transmit more packets now (??) */
907 			netif_wake_queue(ppp->dev);
908 		}
909 		err = 0;
910 		break;
911 
912 #ifdef CONFIG_PPP_FILTER
913 	case PPPIOCSPASS:
914 	case PPPIOCSACTIVE:
915 	{
916 		struct bpf_prog *filter = ppp_get_filter(argp);
917 		struct bpf_prog **which;
918 
919 		if (IS_ERR(filter)) {
920 			err = PTR_ERR(filter);
921 			break;
922 		}
923 		if (cmd == PPPIOCSPASS)
924 			which = &ppp->pass_filter;
925 		else
926 			which = &ppp->active_filter;
927 		ppp_lock(ppp);
928 		if (*which)
929 			bpf_prog_destroy(*which);
930 		*which = filter;
931 		ppp_unlock(ppp);
932 		err = 0;
933 		break;
934 	}
935 #endif /* CONFIG_PPP_FILTER */
936 
937 #ifdef CONFIG_PPP_MULTILINK
938 	case PPPIOCSMRRU:
939 		if (get_user(val, p))
940 			break;
941 		ppp_recv_lock(ppp);
942 		ppp->mrru = val;
943 		ppp_recv_unlock(ppp);
944 		err = 0;
945 		break;
946 #endif /* CONFIG_PPP_MULTILINK */
947 
948 	default:
949 		err = -ENOTTY;
950 	}
951 
952 out:
953 	mutex_unlock(&ppp_mutex);
954 
955 	return err;
956 }
957 
958 #ifdef CONFIG_COMPAT
959 struct ppp_option_data32 {
960 	compat_uptr_t		ptr;
961 	u32			length;
962 	compat_int_t		transmit;
963 };
964 #define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)
965 
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)966 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
967 {
968 	struct ppp_file *pf;
969 	int err = -ENOIOCTLCMD;
970 	void __user *argp = (void __user *)arg;
971 
972 	mutex_lock(&ppp_mutex);
973 
974 	pf = file->private_data;
975 	if (pf && pf->kind == INTERFACE) {
976 		struct ppp *ppp = PF_TO_PPP(pf);
977 		switch (cmd) {
978 #ifdef CONFIG_PPP_FILTER
979 		case PPPIOCSPASS32:
980 		case PPPIOCSACTIVE32:
981 		{
982 			struct bpf_prog *filter = compat_ppp_get_filter(argp);
983 			struct bpf_prog **which;
984 
985 			if (IS_ERR(filter)) {
986 				err = PTR_ERR(filter);
987 				break;
988 			}
989 			if (cmd == PPPIOCSPASS32)
990 				which = &ppp->pass_filter;
991 			else
992 				which = &ppp->active_filter;
993 			ppp_lock(ppp);
994 			if (*which)
995 				bpf_prog_destroy(*which);
996 			*which = filter;
997 			ppp_unlock(ppp);
998 			err = 0;
999 			break;
1000 		}
1001 #endif /* CONFIG_PPP_FILTER */
1002 		case PPPIOCSCOMPRESS32:
1003 		{
1004 			struct ppp_option_data32 data32;
1005 			if (copy_from_user(&data32, argp, sizeof(data32))) {
1006 				err = -EFAULT;
1007 			} else {
1008 				struct ppp_option_data data = {
1009 					.ptr = compat_ptr(data32.ptr),
1010 					.length = data32.length,
1011 					.transmit = data32.transmit
1012 				};
1013 				err = ppp_set_compress(ppp, &data);
1014 			}
1015 			break;
1016 		}
1017 		}
1018 	}
1019 	mutex_unlock(&ppp_mutex);
1020 
1021 	/* all other commands have compatible arguments */
1022 	if (err == -ENOIOCTLCMD)
1023 		err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1024 
1025 	return err;
1026 }
1027 #endif
1028 
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)1029 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1030 			struct file *file, unsigned int cmd, unsigned long arg)
1031 {
1032 	int unit, err = -EFAULT;
1033 	struct ppp *ppp;
1034 	struct channel *chan;
1035 	struct ppp_net *pn;
1036 	int __user *p = (int __user *)arg;
1037 
1038 	switch (cmd) {
1039 	case PPPIOCNEWUNIT:
1040 		/* Create a new ppp unit */
1041 		if (get_user(unit, p))
1042 			break;
1043 		err = ppp_create_interface(net, file, &unit);
1044 		if (err < 0)
1045 			break;
1046 
1047 		err = -EFAULT;
1048 		if (put_user(unit, p))
1049 			break;
1050 		err = 0;
1051 		break;
1052 
1053 	case PPPIOCATTACH:
1054 		/* Attach to an existing ppp unit */
1055 		if (get_user(unit, p))
1056 			break;
1057 		err = -ENXIO;
1058 		pn = ppp_pernet(net);
1059 		mutex_lock(&pn->all_ppp_mutex);
1060 		ppp = ppp_find_unit(pn, unit);
1061 		if (ppp) {
1062 			refcount_inc(&ppp->file.refcnt);
1063 			file->private_data = &ppp->file;
1064 			err = 0;
1065 		}
1066 		mutex_unlock(&pn->all_ppp_mutex);
1067 		break;
1068 
1069 	case PPPIOCATTCHAN:
1070 		if (get_user(unit, p))
1071 			break;
1072 		err = -ENXIO;
1073 		pn = ppp_pernet(net);
1074 		spin_lock_bh(&pn->all_channels_lock);
1075 		chan = ppp_find_channel(pn, unit);
1076 		if (chan) {
1077 			refcount_inc(&chan->file.refcnt);
1078 			file->private_data = &chan->file;
1079 			err = 0;
1080 		}
1081 		spin_unlock_bh(&pn->all_channels_lock);
1082 		break;
1083 
1084 	default:
1085 		err = -ENOTTY;
1086 	}
1087 
1088 	return err;
1089 }
1090 
1091 static const struct file_operations ppp_device_fops = {
1092 	.owner		= THIS_MODULE,
1093 	.read		= ppp_read,
1094 	.write		= ppp_write,
1095 	.poll		= ppp_poll,
1096 	.unlocked_ioctl	= ppp_ioctl,
1097 #ifdef CONFIG_COMPAT
1098 	.compat_ioctl	= ppp_compat_ioctl,
1099 #endif
1100 	.open		= ppp_open,
1101 	.release	= ppp_release,
1102 	.llseek		= noop_llseek,
1103 };
1104 
ppp_init_net(struct net * net)1105 static __net_init int ppp_init_net(struct net *net)
1106 {
1107 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1108 
1109 	idr_init(&pn->units_idr);
1110 	mutex_init(&pn->all_ppp_mutex);
1111 
1112 	INIT_LIST_HEAD(&pn->all_channels);
1113 	INIT_LIST_HEAD(&pn->new_channels);
1114 
1115 	spin_lock_init(&pn->all_channels_lock);
1116 
1117 	return 0;
1118 }
1119 
ppp_exit_net(struct net * net)1120 static __net_exit void ppp_exit_net(struct net *net)
1121 {
1122 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1123 	struct net_device *dev;
1124 	struct net_device *aux;
1125 	struct ppp *ppp;
1126 	LIST_HEAD(list);
1127 	int id;
1128 
1129 	rtnl_lock();
1130 	for_each_netdev_safe(net, dev, aux) {
1131 		if (dev->netdev_ops == &ppp_netdev_ops)
1132 			unregister_netdevice_queue(dev, &list);
1133 	}
1134 
1135 	idr_for_each_entry(&pn->units_idr, ppp, id)
1136 		/* Skip devices already unregistered by previous loop */
1137 		if (!net_eq(dev_net(ppp->dev), net))
1138 			unregister_netdevice_queue(ppp->dev, &list);
1139 
1140 	unregister_netdevice_many(&list);
1141 	rtnl_unlock();
1142 
1143 	mutex_destroy(&pn->all_ppp_mutex);
1144 	idr_destroy(&pn->units_idr);
1145 	WARN_ON_ONCE(!list_empty(&pn->all_channels));
1146 	WARN_ON_ONCE(!list_empty(&pn->new_channels));
1147 }
1148 
1149 static struct pernet_operations ppp_net_ops = {
1150 	.init = ppp_init_net,
1151 	.exit = ppp_exit_net,
1152 	.id   = &ppp_net_id,
1153 	.size = sizeof(struct ppp_net),
1154 };
1155 
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1156 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1157 {
1158 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1159 	int ret;
1160 
1161 	mutex_lock(&pn->all_ppp_mutex);
1162 
1163 	if (unit < 0) {
1164 		ret = unit_get(&pn->units_idr, ppp, 0);
1165 		if (ret < 0)
1166 			goto err;
1167 		if (!ifname_is_set) {
1168 			while (1) {
1169 				snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1170 				if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1171 					break;
1172 				unit_put(&pn->units_idr, ret);
1173 				ret = unit_get(&pn->units_idr, ppp, ret + 1);
1174 				if (ret < 0)
1175 					goto err;
1176 			}
1177 		}
1178 	} else {
1179 		/* Caller asked for a specific unit number. Fail with -EEXIST
1180 		 * if unavailable. For backward compatibility, return -EEXIST
1181 		 * too if idr allocation fails; this makes pppd retry without
1182 		 * requesting a specific unit number.
1183 		 */
1184 		if (unit_find(&pn->units_idr, unit)) {
1185 			ret = -EEXIST;
1186 			goto err;
1187 		}
1188 		ret = unit_set(&pn->units_idr, ppp, unit);
1189 		if (ret < 0) {
1190 			/* Rewrite error for backward compatibility */
1191 			ret = -EEXIST;
1192 			goto err;
1193 		}
1194 	}
1195 	ppp->file.index = ret;
1196 
1197 	if (!ifname_is_set)
1198 		snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1199 
1200 	mutex_unlock(&pn->all_ppp_mutex);
1201 
1202 	ret = register_netdevice(ppp->dev);
1203 	if (ret < 0)
1204 		goto err_unit;
1205 
1206 	atomic_inc(&ppp_unit_count);
1207 
1208 	return 0;
1209 
1210 err_unit:
1211 	mutex_lock(&pn->all_ppp_mutex);
1212 	unit_put(&pn->units_idr, ppp->file.index);
1213 err:
1214 	mutex_unlock(&pn->all_ppp_mutex);
1215 
1216 	return ret;
1217 }
1218 
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1219 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1220 			     const struct ppp_config *conf)
1221 {
1222 	struct ppp *ppp = netdev_priv(dev);
1223 	int indx;
1224 	int err;
1225 	int cpu;
1226 
1227 	ppp->dev = dev;
1228 	ppp->ppp_net = src_net;
1229 	ppp->mru = PPP_MRU;
1230 	ppp->owner = conf->file;
1231 
1232 	init_ppp_file(&ppp->file, INTERFACE);
1233 	ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1234 
1235 	for (indx = 0; indx < NUM_NP; ++indx)
1236 		ppp->npmode[indx] = NPMODE_PASS;
1237 	INIT_LIST_HEAD(&ppp->channels);
1238 	spin_lock_init(&ppp->rlock);
1239 	spin_lock_init(&ppp->wlock);
1240 
1241 	ppp->xmit_recursion = alloc_percpu(int);
1242 	if (!ppp->xmit_recursion) {
1243 		err = -ENOMEM;
1244 		goto err1;
1245 	}
1246 	for_each_possible_cpu(cpu)
1247 		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1248 
1249 #ifdef CONFIG_PPP_MULTILINK
1250 	ppp->minseq = -1;
1251 	skb_queue_head_init(&ppp->mrq);
1252 #endif /* CONFIG_PPP_MULTILINK */
1253 #ifdef CONFIG_PPP_FILTER
1254 	ppp->pass_filter = NULL;
1255 	ppp->active_filter = NULL;
1256 #endif /* CONFIG_PPP_FILTER */
1257 
1258 	err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1259 	if (err < 0)
1260 		goto err2;
1261 
1262 	conf->file->private_data = &ppp->file;
1263 
1264 	return 0;
1265 err2:
1266 	free_percpu(ppp->xmit_recursion);
1267 err1:
1268 	return err;
1269 }
1270 
1271 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1272 	[IFLA_PPP_DEV_FD]	= { .type = NLA_S32 },
1273 };
1274 
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1275 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1276 			   struct netlink_ext_ack *extack)
1277 {
1278 	if (!data)
1279 		return -EINVAL;
1280 
1281 	if (!data[IFLA_PPP_DEV_FD])
1282 		return -EINVAL;
1283 	if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1284 		return -EBADF;
1285 
1286 	return 0;
1287 }
1288 
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1289 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1290 			  struct nlattr *tb[], struct nlattr *data[],
1291 			  struct netlink_ext_ack *extack)
1292 {
1293 	struct ppp_config conf = {
1294 		.unit = -1,
1295 		.ifname_is_set = true,
1296 	};
1297 	struct file *file;
1298 	int err;
1299 
1300 	file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1301 	if (!file)
1302 		return -EBADF;
1303 
1304 	/* rtnl_lock is already held here, but ppp_create_interface() locks
1305 	 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1306 	 * possible deadlock due to lock order inversion, at the cost of
1307 	 * pushing the problem back to userspace.
1308 	 */
1309 	if (!mutex_trylock(&ppp_mutex)) {
1310 		err = -EBUSY;
1311 		goto out;
1312 	}
1313 
1314 	if (file->f_op != &ppp_device_fops || file->private_data) {
1315 		err = -EBADF;
1316 		goto out_unlock;
1317 	}
1318 
1319 	conf.file = file;
1320 
1321 	/* Don't use device name generated by the rtnetlink layer when ifname
1322 	 * isn't specified. Let ppp_dev_configure() set the device name using
1323 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1324 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1325 	 */
1326 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1327 		conf.ifname_is_set = false;
1328 
1329 	err = ppp_dev_configure(src_net, dev, &conf);
1330 
1331 out_unlock:
1332 	mutex_unlock(&ppp_mutex);
1333 out:
1334 	fput(file);
1335 
1336 	return err;
1337 }
1338 
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1339 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1340 {
1341 	unregister_netdevice_queue(dev, head);
1342 }
1343 
ppp_nl_get_size(const struct net_device * dev)1344 static size_t ppp_nl_get_size(const struct net_device *dev)
1345 {
1346 	return 0;
1347 }
1348 
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1349 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1350 {
1351 	return 0;
1352 }
1353 
ppp_nl_get_link_net(const struct net_device * dev)1354 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1355 {
1356 	struct ppp *ppp = netdev_priv(dev);
1357 
1358 	return ppp->ppp_net;
1359 }
1360 
1361 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1362 	.kind		= "ppp",
1363 	.maxtype	= IFLA_PPP_MAX,
1364 	.policy		= ppp_nl_policy,
1365 	.priv_size	= sizeof(struct ppp),
1366 	.setup		= ppp_setup,
1367 	.validate	= ppp_nl_validate,
1368 	.newlink	= ppp_nl_newlink,
1369 	.dellink	= ppp_nl_dellink,
1370 	.get_size	= ppp_nl_get_size,
1371 	.fill_info	= ppp_nl_fill_info,
1372 	.get_link_net	= ppp_nl_get_link_net,
1373 };
1374 
1375 #define PPP_MAJOR	108
1376 
1377 /* Called at boot time if ppp is compiled into the kernel,
1378    or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1379 static int __init ppp_init(void)
1380 {
1381 	int err;
1382 
1383 	pr_info("PPP generic driver version " PPP_VERSION "\n");
1384 
1385 	err = register_pernet_device(&ppp_net_ops);
1386 	if (err) {
1387 		pr_err("failed to register PPP pernet device (%d)\n", err);
1388 		goto out;
1389 	}
1390 
1391 	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1392 	if (err) {
1393 		pr_err("failed to register PPP device (%d)\n", err);
1394 		goto out_net;
1395 	}
1396 
1397 	ppp_class = class_create(THIS_MODULE, "ppp");
1398 	if (IS_ERR(ppp_class)) {
1399 		err = PTR_ERR(ppp_class);
1400 		goto out_chrdev;
1401 	}
1402 
1403 	err = rtnl_link_register(&ppp_link_ops);
1404 	if (err) {
1405 		pr_err("failed to register rtnetlink PPP handler\n");
1406 		goto out_class;
1407 	}
1408 
1409 	/* not a big deal if we fail here :-) */
1410 	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1411 
1412 	return 0;
1413 
1414 out_class:
1415 	class_destroy(ppp_class);
1416 out_chrdev:
1417 	unregister_chrdev(PPP_MAJOR, "ppp");
1418 out_net:
1419 	unregister_pernet_device(&ppp_net_ops);
1420 out:
1421 	return err;
1422 }
1423 
1424 /*
1425  * Network interface unit routines.
1426  */
1427 static netdev_tx_t
ppp_start_xmit(struct sk_buff * skb,struct net_device * dev)1428 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1429 {
1430 	struct ppp *ppp = netdev_priv(dev);
1431 	int npi, proto;
1432 	unsigned char *pp;
1433 
1434 	npi = ethertype_to_npindex(ntohs(skb->protocol));
1435 	if (npi < 0)
1436 		goto outf;
1437 
1438 	/* Drop, accept or reject the packet */
1439 	switch (ppp->npmode[npi]) {
1440 	case NPMODE_PASS:
1441 		break;
1442 	case NPMODE_QUEUE:
1443 		/* it would be nice to have a way to tell the network
1444 		   system to queue this one up for later. */
1445 		goto outf;
1446 	case NPMODE_DROP:
1447 	case NPMODE_ERROR:
1448 		goto outf;
1449 	}
1450 
1451 	/* Put the 2-byte PPP protocol number on the front,
1452 	   making sure there is room for the address and control fields. */
1453 	if (skb_cow_head(skb, PPP_HDRLEN))
1454 		goto outf;
1455 
1456 	pp = skb_push(skb, 2);
1457 	proto = npindex_to_proto[npi];
1458 	put_unaligned_be16(proto, pp);
1459 
1460 	skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1461 	ppp_xmit_process(ppp, skb);
1462 
1463 	return NETDEV_TX_OK;
1464 
1465  outf:
1466 	kfree_skb(skb);
1467 	++dev->stats.tx_dropped;
1468 	return NETDEV_TX_OK;
1469 }
1470 
1471 static int
ppp_net_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * addr,int cmd)1472 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1473 		       void __user *addr, int cmd)
1474 {
1475 	struct ppp *ppp = netdev_priv(dev);
1476 	int err = -EFAULT;
1477 	struct ppp_stats stats;
1478 	struct ppp_comp_stats cstats;
1479 	char *vers;
1480 
1481 	switch (cmd) {
1482 	case SIOCGPPPSTATS:
1483 		ppp_get_stats(ppp, &stats);
1484 		if (copy_to_user(addr, &stats, sizeof(stats)))
1485 			break;
1486 		err = 0;
1487 		break;
1488 
1489 	case SIOCGPPPCSTATS:
1490 		memset(&cstats, 0, sizeof(cstats));
1491 		if (ppp->xc_state)
1492 			ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1493 		if (ppp->rc_state)
1494 			ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1495 		if (copy_to_user(addr, &cstats, sizeof(cstats)))
1496 			break;
1497 		err = 0;
1498 		break;
1499 
1500 	case SIOCGPPPVER:
1501 		vers = PPP_VERSION;
1502 		if (copy_to_user(addr, vers, strlen(vers) + 1))
1503 			break;
1504 		err = 0;
1505 		break;
1506 
1507 	default:
1508 		err = -EINVAL;
1509 	}
1510 
1511 	return err;
1512 }
1513 
1514 static void
ppp_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats64)1515 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1516 {
1517 	struct ppp *ppp = netdev_priv(dev);
1518 
1519 	ppp_recv_lock(ppp);
1520 	stats64->rx_packets = ppp->stats64.rx_packets;
1521 	stats64->rx_bytes   = ppp->stats64.rx_bytes;
1522 	ppp_recv_unlock(ppp);
1523 
1524 	ppp_xmit_lock(ppp);
1525 	stats64->tx_packets = ppp->stats64.tx_packets;
1526 	stats64->tx_bytes   = ppp->stats64.tx_bytes;
1527 	ppp_xmit_unlock(ppp);
1528 
1529 	stats64->rx_errors        = dev->stats.rx_errors;
1530 	stats64->tx_errors        = dev->stats.tx_errors;
1531 	stats64->rx_dropped       = dev->stats.rx_dropped;
1532 	stats64->tx_dropped       = dev->stats.tx_dropped;
1533 	stats64->rx_length_errors = dev->stats.rx_length_errors;
1534 }
1535 
ppp_dev_init(struct net_device * dev)1536 static int ppp_dev_init(struct net_device *dev)
1537 {
1538 	struct ppp *ppp;
1539 
1540 	netdev_lockdep_set_classes(dev);
1541 
1542 	ppp = netdev_priv(dev);
1543 	/* Let the netdevice take a reference on the ppp file. This ensures
1544 	 * that ppp_destroy_interface() won't run before the device gets
1545 	 * unregistered.
1546 	 */
1547 	refcount_inc(&ppp->file.refcnt);
1548 
1549 	return 0;
1550 }
1551 
ppp_dev_uninit(struct net_device * dev)1552 static void ppp_dev_uninit(struct net_device *dev)
1553 {
1554 	struct ppp *ppp = netdev_priv(dev);
1555 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1556 
1557 	ppp_lock(ppp);
1558 	ppp->closing = 1;
1559 	ppp_unlock(ppp);
1560 
1561 	mutex_lock(&pn->all_ppp_mutex);
1562 	unit_put(&pn->units_idr, ppp->file.index);
1563 	mutex_unlock(&pn->all_ppp_mutex);
1564 
1565 	ppp->owner = NULL;
1566 
1567 	ppp->file.dead = 1;
1568 	wake_up_interruptible(&ppp->file.rwait);
1569 }
1570 
ppp_dev_priv_destructor(struct net_device * dev)1571 static void ppp_dev_priv_destructor(struct net_device *dev)
1572 {
1573 	struct ppp *ppp;
1574 
1575 	ppp = netdev_priv(dev);
1576 	if (refcount_dec_and_test(&ppp->file.refcnt))
1577 		ppp_destroy_interface(ppp);
1578 }
1579 
ppp_fill_forward_path(struct net_device_path_ctx * ctx,struct net_device_path * path)1580 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1581 				 struct net_device_path *path)
1582 {
1583 	struct ppp *ppp = netdev_priv(ctx->dev);
1584 	struct ppp_channel *chan;
1585 	struct channel *pch;
1586 
1587 	if (ppp->flags & SC_MULTILINK)
1588 		return -EOPNOTSUPP;
1589 
1590 	if (list_empty(&ppp->channels))
1591 		return -ENODEV;
1592 
1593 	pch = list_first_entry(&ppp->channels, struct channel, clist);
1594 	chan = pch->chan;
1595 	if (!chan->ops->fill_forward_path)
1596 		return -EOPNOTSUPP;
1597 
1598 	return chan->ops->fill_forward_path(ctx, path, chan);
1599 }
1600 
1601 static const struct net_device_ops ppp_netdev_ops = {
1602 	.ndo_init	 = ppp_dev_init,
1603 	.ndo_uninit      = ppp_dev_uninit,
1604 	.ndo_start_xmit  = ppp_start_xmit,
1605 	.ndo_siocdevprivate = ppp_net_siocdevprivate,
1606 	.ndo_get_stats64 = ppp_get_stats64,
1607 	.ndo_fill_forward_path = ppp_fill_forward_path,
1608 };
1609 
1610 static struct device_type ppp_type = {
1611 	.name = "ppp",
1612 };
1613 
ppp_setup(struct net_device * dev)1614 static void ppp_setup(struct net_device *dev)
1615 {
1616 	dev->netdev_ops = &ppp_netdev_ops;
1617 	SET_NETDEV_DEVTYPE(dev, &ppp_type);
1618 
1619 	dev->features |= NETIF_F_LLTX;
1620 
1621 	dev->hard_header_len = PPP_HDRLEN;
1622 	dev->mtu = PPP_MRU;
1623 	dev->addr_len = 0;
1624 	dev->tx_queue_len = 3;
1625 	dev->type = ARPHRD_PPP;
1626 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1627 	dev->priv_destructor = ppp_dev_priv_destructor;
1628 	netif_keep_dst(dev);
1629 }
1630 
1631 /*
1632  * Transmit-side routines.
1633  */
1634 
1635 /* 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)1636 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1637 {
1638 	ppp_xmit_lock(ppp);
1639 	if (!ppp->closing) {
1640 		ppp_push(ppp);
1641 
1642 		if (skb)
1643 			skb_queue_tail(&ppp->file.xq, skb);
1644 		while (!ppp->xmit_pending &&
1645 		       (skb = skb_dequeue(&ppp->file.xq)))
1646 			ppp_send_frame(ppp, skb);
1647 		/* If there's no work left to do, tell the core net
1648 		   code that we can accept some more. */
1649 		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1650 			netif_wake_queue(ppp->dev);
1651 		else
1652 			netif_stop_queue(ppp->dev);
1653 	} else {
1654 		kfree_skb(skb);
1655 	}
1656 	ppp_xmit_unlock(ppp);
1657 }
1658 
ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1659 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1660 {
1661 	local_bh_disable();
1662 
1663 	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1664 		goto err;
1665 
1666 	(*this_cpu_ptr(ppp->xmit_recursion))++;
1667 	__ppp_xmit_process(ppp, skb);
1668 	(*this_cpu_ptr(ppp->xmit_recursion))--;
1669 
1670 	local_bh_enable();
1671 
1672 	return;
1673 
1674 err:
1675 	local_bh_enable();
1676 
1677 	kfree_skb(skb);
1678 
1679 	if (net_ratelimit())
1680 		netdev_err(ppp->dev, "recursion detected\n");
1681 }
1682 
1683 static inline struct sk_buff *
pad_compress_skb(struct ppp * ppp,struct sk_buff * skb)1684 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1685 {
1686 	struct sk_buff *new_skb;
1687 	int len;
1688 	int new_skb_size = ppp->dev->mtu +
1689 		ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1690 	int compressor_skb_size = ppp->dev->mtu +
1691 		ppp->xcomp->comp_extra + PPP_HDRLEN;
1692 	new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1693 	if (!new_skb) {
1694 		if (net_ratelimit())
1695 			netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1696 		return NULL;
1697 	}
1698 	if (ppp->dev->hard_header_len > PPP_HDRLEN)
1699 		skb_reserve(new_skb,
1700 			    ppp->dev->hard_header_len - PPP_HDRLEN);
1701 
1702 	/* compressor still expects A/C bytes in hdr */
1703 	len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1704 				   new_skb->data, skb->len + 2,
1705 				   compressor_skb_size);
1706 	if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1707 		consume_skb(skb);
1708 		skb = new_skb;
1709 		skb_put(skb, len);
1710 		skb_pull(skb, 2);	/* pull off A/C bytes */
1711 	} else if (len == 0) {
1712 		/* didn't compress, or CCP not up yet */
1713 		consume_skb(new_skb);
1714 		new_skb = skb;
1715 	} else {
1716 		/*
1717 		 * (len < 0)
1718 		 * MPPE requires that we do not send unencrypted
1719 		 * frames.  The compressor will return -1 if we
1720 		 * should drop the frame.  We cannot simply test
1721 		 * the compress_proto because MPPE and MPPC share
1722 		 * the same number.
1723 		 */
1724 		if (net_ratelimit())
1725 			netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1726 		kfree_skb(skb);
1727 		consume_skb(new_skb);
1728 		new_skb = NULL;
1729 	}
1730 	return new_skb;
1731 }
1732 
1733 /*
1734  * Compress and send a frame.
1735  * The caller should have locked the xmit path,
1736  * and xmit_pending should be 0.
1737  */
1738 static void
ppp_send_frame(struct ppp * ppp,struct sk_buff * skb)1739 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1740 {
1741 	int proto = PPP_PROTO(skb);
1742 	struct sk_buff *new_skb;
1743 	int len;
1744 	unsigned char *cp;
1745 
1746 	if (proto < 0x8000) {
1747 #ifdef CONFIG_PPP_FILTER
1748 		/* check if we should pass this packet */
1749 		/* the filter instructions are constructed assuming
1750 		   a four-byte PPP header on each packet */
1751 		*(u8 *)skb_push(skb, 2) = 1;
1752 		if (ppp->pass_filter &&
1753 		    bpf_prog_run(ppp->pass_filter, skb) == 0) {
1754 			if (ppp->debug & 1)
1755 				netdev_printk(KERN_DEBUG, ppp->dev,
1756 					      "PPP: outbound frame "
1757 					      "not passed\n");
1758 			kfree_skb(skb);
1759 			return;
1760 		}
1761 		/* if this packet passes the active filter, record the time */
1762 		if (!(ppp->active_filter &&
1763 		      bpf_prog_run(ppp->active_filter, skb) == 0))
1764 			ppp->last_xmit = jiffies;
1765 		skb_pull(skb, 2);
1766 #else
1767 		/* for data packets, record the time */
1768 		ppp->last_xmit = jiffies;
1769 #endif /* CONFIG_PPP_FILTER */
1770 	}
1771 
1772 	++ppp->stats64.tx_packets;
1773 	ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1774 
1775 	switch (proto) {
1776 	case PPP_IP:
1777 		if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1778 			break;
1779 		/* try to do VJ TCP header compression */
1780 		new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1781 				    GFP_ATOMIC);
1782 		if (!new_skb) {
1783 			netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1784 			goto drop;
1785 		}
1786 		skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1787 		cp = skb->data + 2;
1788 		len = slhc_compress(ppp->vj, cp, skb->len - 2,
1789 				    new_skb->data + 2, &cp,
1790 				    !(ppp->flags & SC_NO_TCP_CCID));
1791 		if (cp == skb->data + 2) {
1792 			/* didn't compress */
1793 			consume_skb(new_skb);
1794 		} else {
1795 			if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1796 				proto = PPP_VJC_COMP;
1797 				cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1798 			} else {
1799 				proto = PPP_VJC_UNCOMP;
1800 				cp[0] = skb->data[2];
1801 			}
1802 			consume_skb(skb);
1803 			skb = new_skb;
1804 			cp = skb_put(skb, len + 2);
1805 			cp[0] = 0;
1806 			cp[1] = proto;
1807 		}
1808 		break;
1809 
1810 	case PPP_CCP:
1811 		/* peek at outbound CCP frames */
1812 		ppp_ccp_peek(ppp, skb, 0);
1813 		break;
1814 	}
1815 
1816 	/* try to do packet compression */
1817 	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1818 	    proto != PPP_LCP && proto != PPP_CCP) {
1819 		if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1820 			if (net_ratelimit())
1821 				netdev_err(ppp->dev,
1822 					   "ppp: compression required but "
1823 					   "down - pkt dropped.\n");
1824 			goto drop;
1825 		}
1826 		skb = pad_compress_skb(ppp, skb);
1827 		if (!skb)
1828 			goto drop;
1829 	}
1830 
1831 	/*
1832 	 * If we are waiting for traffic (demand dialling),
1833 	 * queue it up for pppd to receive.
1834 	 */
1835 	if (ppp->flags & SC_LOOP_TRAFFIC) {
1836 		if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1837 			goto drop;
1838 		skb_queue_tail(&ppp->file.rq, skb);
1839 		wake_up_interruptible(&ppp->file.rwait);
1840 		return;
1841 	}
1842 
1843 	ppp->xmit_pending = skb;
1844 	ppp_push(ppp);
1845 	return;
1846 
1847  drop:
1848 	kfree_skb(skb);
1849 	++ppp->dev->stats.tx_errors;
1850 }
1851 
1852 /*
1853  * Try to send the frame in xmit_pending.
1854  * The caller should have the xmit path locked.
1855  */
1856 static void
ppp_push(struct ppp * ppp)1857 ppp_push(struct ppp *ppp)
1858 {
1859 	struct list_head *list;
1860 	struct channel *pch;
1861 	struct sk_buff *skb = ppp->xmit_pending;
1862 
1863 	if (!skb)
1864 		return;
1865 
1866 	list = &ppp->channels;
1867 	if (list_empty(list)) {
1868 		/* nowhere to send the packet, just drop it */
1869 		ppp->xmit_pending = NULL;
1870 		kfree_skb(skb);
1871 		return;
1872 	}
1873 
1874 	if ((ppp->flags & SC_MULTILINK) == 0) {
1875 		/* not doing multilink: send it down the first channel */
1876 		list = list->next;
1877 		pch = list_entry(list, struct channel, clist);
1878 
1879 		spin_lock(&pch->downl);
1880 		if (pch->chan) {
1881 			if (pch->chan->ops->start_xmit(pch->chan, skb))
1882 				ppp->xmit_pending = NULL;
1883 		} else {
1884 			/* channel got unregistered */
1885 			kfree_skb(skb);
1886 			ppp->xmit_pending = NULL;
1887 		}
1888 		spin_unlock(&pch->downl);
1889 		return;
1890 	}
1891 
1892 #ifdef CONFIG_PPP_MULTILINK
1893 	/* Multilink: fragment the packet over as many links
1894 	   as can take the packet at the moment. */
1895 	if (!ppp_mp_explode(ppp, skb))
1896 		return;
1897 #endif /* CONFIG_PPP_MULTILINK */
1898 
1899 	ppp->xmit_pending = NULL;
1900 	kfree_skb(skb);
1901 }
1902 
1903 #ifdef CONFIG_PPP_MULTILINK
1904 static bool mp_protocol_compress __read_mostly = true;
1905 module_param(mp_protocol_compress, bool, 0644);
1906 MODULE_PARM_DESC(mp_protocol_compress,
1907 		 "compress protocol id in multilink fragments");
1908 
1909 /*
1910  * Divide a packet to be transmitted into fragments and
1911  * send them out the individual links.
1912  */
ppp_mp_explode(struct ppp * ppp,struct sk_buff * skb)1913 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1914 {
1915 	int len, totlen;
1916 	int i, bits, hdrlen, mtu;
1917 	int flen;
1918 	int navail, nfree, nzero;
1919 	int nbigger;
1920 	int totspeed;
1921 	int totfree;
1922 	unsigned char *p, *q;
1923 	struct list_head *list;
1924 	struct channel *pch;
1925 	struct sk_buff *frag;
1926 	struct ppp_channel *chan;
1927 
1928 	totspeed = 0; /*total bitrate of the bundle*/
1929 	nfree = 0; /* # channels which have no packet already queued */
1930 	navail = 0; /* total # of usable channels (not deregistered) */
1931 	nzero = 0; /* number of channels with zero speed associated*/
1932 	totfree = 0; /*total # of channels available and
1933 				  *having no queued packets before
1934 				  *starting the fragmentation*/
1935 
1936 	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1937 	i = 0;
1938 	list_for_each_entry(pch, &ppp->channels, clist) {
1939 		if (pch->chan) {
1940 			pch->avail = 1;
1941 			navail++;
1942 			pch->speed = pch->chan->speed;
1943 		} else {
1944 			pch->avail = 0;
1945 		}
1946 		if (pch->avail) {
1947 			if (skb_queue_empty(&pch->file.xq) ||
1948 				!pch->had_frag) {
1949 					if (pch->speed == 0)
1950 						nzero++;
1951 					else
1952 						totspeed += pch->speed;
1953 
1954 					pch->avail = 2;
1955 					++nfree;
1956 					++totfree;
1957 				}
1958 			if (!pch->had_frag && i < ppp->nxchan)
1959 				ppp->nxchan = i;
1960 		}
1961 		++i;
1962 	}
1963 	/*
1964 	 * Don't start sending this packet unless at least half of
1965 	 * the channels are free.  This gives much better TCP
1966 	 * performance if we have a lot of channels.
1967 	 */
1968 	if (nfree == 0 || nfree < navail / 2)
1969 		return 0; /* can't take now, leave it in xmit_pending */
1970 
1971 	/* Do protocol field compression */
1972 	p = skb->data;
1973 	len = skb->len;
1974 	if (*p == 0 && mp_protocol_compress) {
1975 		++p;
1976 		--len;
1977 	}
1978 
1979 	totlen = len;
1980 	nbigger = len % nfree;
1981 
1982 	/* skip to the channel after the one we last used
1983 	   and start at that one */
1984 	list = &ppp->channels;
1985 	for (i = 0; i < ppp->nxchan; ++i) {
1986 		list = list->next;
1987 		if (list == &ppp->channels) {
1988 			i = 0;
1989 			break;
1990 		}
1991 	}
1992 
1993 	/* create a fragment for each channel */
1994 	bits = B;
1995 	while (len > 0) {
1996 		list = list->next;
1997 		if (list == &ppp->channels) {
1998 			i = 0;
1999 			continue;
2000 		}
2001 		pch = list_entry(list, struct channel, clist);
2002 		++i;
2003 		if (!pch->avail)
2004 			continue;
2005 
2006 		/*
2007 		 * Skip this channel if it has a fragment pending already and
2008 		 * we haven't given a fragment to all of the free channels.
2009 		 */
2010 		if (pch->avail == 1) {
2011 			if (nfree > 0)
2012 				continue;
2013 		} else {
2014 			pch->avail = 1;
2015 		}
2016 
2017 		/* check the channel's mtu and whether it is still attached. */
2018 		spin_lock(&pch->downl);
2019 		if (pch->chan == NULL) {
2020 			/* can't use this channel, it's being deregistered */
2021 			if (pch->speed == 0)
2022 				nzero--;
2023 			else
2024 				totspeed -= pch->speed;
2025 
2026 			spin_unlock(&pch->downl);
2027 			pch->avail = 0;
2028 			totlen = len;
2029 			totfree--;
2030 			nfree--;
2031 			if (--navail == 0)
2032 				break;
2033 			continue;
2034 		}
2035 
2036 		/*
2037 		*if the channel speed is not set divide
2038 		*the packet evenly among the free channels;
2039 		*otherwise divide it according to the speed
2040 		*of the channel we are going to transmit on
2041 		*/
2042 		flen = len;
2043 		if (nfree > 0) {
2044 			if (pch->speed == 0) {
2045 				flen = len/nfree;
2046 				if (nbigger > 0) {
2047 					flen++;
2048 					nbigger--;
2049 				}
2050 			} else {
2051 				flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2052 					((totspeed*totfree)/pch->speed)) - hdrlen;
2053 				if (nbigger > 0) {
2054 					flen += ((totfree - nzero)*pch->speed)/totspeed;
2055 					nbigger -= ((totfree - nzero)*pch->speed)/
2056 							totspeed;
2057 				}
2058 			}
2059 			nfree--;
2060 		}
2061 
2062 		/*
2063 		 *check if we are on the last channel or
2064 		 *we exceded the length of the data to
2065 		 *fragment
2066 		 */
2067 		if ((nfree <= 0) || (flen > len))
2068 			flen = len;
2069 		/*
2070 		 *it is not worth to tx on slow channels:
2071 		 *in that case from the resulting flen according to the
2072 		 *above formula will be equal or less than zero.
2073 		 *Skip the channel in this case
2074 		 */
2075 		if (flen <= 0) {
2076 			pch->avail = 2;
2077 			spin_unlock(&pch->downl);
2078 			continue;
2079 		}
2080 
2081 		/*
2082 		 * hdrlen includes the 2-byte PPP protocol field, but the
2083 		 * MTU counts only the payload excluding the protocol field.
2084 		 * (RFC1661 Section 2)
2085 		 */
2086 		mtu = pch->chan->mtu - (hdrlen - 2);
2087 		if (mtu < 4)
2088 			mtu = 4;
2089 		if (flen > mtu)
2090 			flen = mtu;
2091 		if (flen == len)
2092 			bits |= E;
2093 		frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2094 		if (!frag)
2095 			goto noskb;
2096 		q = skb_put(frag, flen + hdrlen);
2097 
2098 		/* make the MP header */
2099 		put_unaligned_be16(PPP_MP, q);
2100 		if (ppp->flags & SC_MP_XSHORTSEQ) {
2101 			q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2102 			q[3] = ppp->nxseq;
2103 		} else {
2104 			q[2] = bits;
2105 			q[3] = ppp->nxseq >> 16;
2106 			q[4] = ppp->nxseq >> 8;
2107 			q[5] = ppp->nxseq;
2108 		}
2109 
2110 		memcpy(q + hdrlen, p, flen);
2111 
2112 		/* try to send it down the channel */
2113 		chan = pch->chan;
2114 		if (!skb_queue_empty(&pch->file.xq) ||
2115 			!chan->ops->start_xmit(chan, frag))
2116 			skb_queue_tail(&pch->file.xq, frag);
2117 		pch->had_frag = 1;
2118 		p += flen;
2119 		len -= flen;
2120 		++ppp->nxseq;
2121 		bits = 0;
2122 		spin_unlock(&pch->downl);
2123 	}
2124 	ppp->nxchan = i;
2125 
2126 	return 1;
2127 
2128  noskb:
2129 	spin_unlock(&pch->downl);
2130 	if (ppp->debug & 1)
2131 		netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2132 	++ppp->dev->stats.tx_errors;
2133 	++ppp->nxseq;
2134 	return 1;	/* abandon the frame */
2135 }
2136 #endif /* CONFIG_PPP_MULTILINK */
2137 
2138 /* Try to send data out on a channel */
__ppp_channel_push(struct channel * pch)2139 static void __ppp_channel_push(struct channel *pch)
2140 {
2141 	struct sk_buff *skb;
2142 	struct ppp *ppp;
2143 
2144 	spin_lock(&pch->downl);
2145 	if (pch->chan) {
2146 		while (!skb_queue_empty(&pch->file.xq)) {
2147 			skb = skb_dequeue(&pch->file.xq);
2148 			if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2149 				/* put the packet back and try again later */
2150 				skb_queue_head(&pch->file.xq, skb);
2151 				break;
2152 			}
2153 		}
2154 	} else {
2155 		/* channel got deregistered */
2156 		skb_queue_purge(&pch->file.xq);
2157 	}
2158 	spin_unlock(&pch->downl);
2159 	/* see if there is anything from the attached unit to be sent */
2160 	if (skb_queue_empty(&pch->file.xq)) {
2161 		ppp = pch->ppp;
2162 		if (ppp)
2163 			__ppp_xmit_process(ppp, NULL);
2164 	}
2165 }
2166 
ppp_channel_push(struct channel * pch)2167 static void ppp_channel_push(struct channel *pch)
2168 {
2169 	read_lock_bh(&pch->upl);
2170 	if (pch->ppp) {
2171 		(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2172 		__ppp_channel_push(pch);
2173 		(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2174 	} else {
2175 		__ppp_channel_push(pch);
2176 	}
2177 	read_unlock_bh(&pch->upl);
2178 }
2179 
2180 /*
2181  * Receive-side routines.
2182  */
2183 
2184 struct ppp_mp_skb_parm {
2185 	u32		sequence;
2186 	u8		BEbits;
2187 };
2188 #define PPP_MP_CB(skb)	((struct ppp_mp_skb_parm *)((skb)->cb))
2189 
2190 static inline void
ppp_do_recv(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2191 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2192 {
2193 	ppp_recv_lock(ppp);
2194 	if (!ppp->closing)
2195 		ppp_receive_frame(ppp, skb, pch);
2196 	else
2197 		kfree_skb(skb);
2198 	ppp_recv_unlock(ppp);
2199 }
2200 
2201 /**
2202  * __ppp_decompress_proto - Decompress protocol field, slim version.
2203  * @skb: Socket buffer where protocol field should be decompressed. It must have
2204  *	 at least 1 byte of head room and 1 byte of linear data. First byte of
2205  *	 data must be a protocol field byte.
2206  *
2207  * Decompress protocol field in PPP header if it's compressed, e.g. when
2208  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2209  * length are done in this function.
2210  */
__ppp_decompress_proto(struct sk_buff * skb)2211 static void __ppp_decompress_proto(struct sk_buff *skb)
2212 {
2213 	if (skb->data[0] & 0x01)
2214 		*(u8 *)skb_push(skb, 1) = 0x00;
2215 }
2216 
2217 /**
2218  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2219  * @skb: Socket buffer where protocol field should be decompressed. First byte
2220  *	 of data must be a protocol field byte.
2221  *
2222  * Decompress protocol field in PPP header if it's compressed, e.g. when
2223  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2224  * sure that skb data room is sufficient for Protocol field, before and after
2225  * decompression.
2226  *
2227  * Return: true - decompressed successfully, false - not enough room in skb.
2228  */
ppp_decompress_proto(struct sk_buff * skb)2229 static bool ppp_decompress_proto(struct sk_buff *skb)
2230 {
2231 	/* At least one byte should be present (if protocol is compressed) */
2232 	if (!pskb_may_pull(skb, 1))
2233 		return false;
2234 
2235 	__ppp_decompress_proto(skb);
2236 
2237 	/* Protocol field should occupy 2 bytes when not compressed */
2238 	return pskb_may_pull(skb, 2);
2239 }
2240 
2241 /* Attempt to handle a frame via. a bridged channel, if one exists.
2242  * If the channel is bridged, the frame is consumed by the bridge.
2243  * If not, the caller must handle the frame by normal recv mechanisms.
2244  * Returns true if the frame is consumed, false otherwise.
2245  */
ppp_channel_bridge_input(struct channel * pch,struct sk_buff * skb)2246 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2247 {
2248 	struct channel *pchb;
2249 
2250 	rcu_read_lock();
2251 	pchb = rcu_dereference(pch->bridge);
2252 	if (!pchb)
2253 		goto out_rcu;
2254 
2255 	spin_lock(&pchb->downl);
2256 	if (!pchb->chan) {
2257 		/* channel got unregistered */
2258 		kfree_skb(skb);
2259 		goto outl;
2260 	}
2261 
2262 	skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2263 	if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2264 		kfree_skb(skb);
2265 
2266 outl:
2267 	spin_unlock(&pchb->downl);
2268 out_rcu:
2269 	rcu_read_unlock();
2270 
2271 	/* If pchb is set then we've consumed the packet */
2272 	return !!pchb;
2273 }
2274 
2275 void
ppp_input(struct ppp_channel * chan,struct sk_buff * skb)2276 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2277 {
2278 	struct channel *pch = chan->ppp;
2279 	int proto;
2280 
2281 	if (!pch) {
2282 		kfree_skb(skb);
2283 		return;
2284 	}
2285 
2286 	/* If the channel is bridged, transmit via. bridge */
2287 	if (ppp_channel_bridge_input(pch, skb))
2288 		return;
2289 
2290 	read_lock_bh(&pch->upl);
2291 	if (!ppp_decompress_proto(skb)) {
2292 		kfree_skb(skb);
2293 		if (pch->ppp) {
2294 			++pch->ppp->dev->stats.rx_length_errors;
2295 			ppp_receive_error(pch->ppp);
2296 		}
2297 		goto done;
2298 	}
2299 
2300 	proto = PPP_PROTO(skb);
2301 	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2302 		/* put it on the channel queue */
2303 		skb_queue_tail(&pch->file.rq, skb);
2304 		/* drop old frames if queue too long */
2305 		while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2306 		       (skb = skb_dequeue(&pch->file.rq)))
2307 			kfree_skb(skb);
2308 		wake_up_interruptible(&pch->file.rwait);
2309 	} else {
2310 		ppp_do_recv(pch->ppp, skb, pch);
2311 	}
2312 
2313 done:
2314 	read_unlock_bh(&pch->upl);
2315 }
2316 
2317 /* Put a 0-length skb in the receive queue as an error indication */
2318 void
ppp_input_error(struct ppp_channel * chan,int code)2319 ppp_input_error(struct ppp_channel *chan, int code)
2320 {
2321 	struct channel *pch = chan->ppp;
2322 	struct sk_buff *skb;
2323 
2324 	if (!pch)
2325 		return;
2326 
2327 	read_lock_bh(&pch->upl);
2328 	if (pch->ppp) {
2329 		skb = alloc_skb(0, GFP_ATOMIC);
2330 		if (skb) {
2331 			skb->len = 0;		/* probably unnecessary */
2332 			skb->cb[0] = code;
2333 			ppp_do_recv(pch->ppp, skb, pch);
2334 		}
2335 	}
2336 	read_unlock_bh(&pch->upl);
2337 }
2338 
2339 /*
2340  * We come in here to process a received frame.
2341  * The receive side of the ppp unit is locked.
2342  */
2343 static void
ppp_receive_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2344 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2345 {
2346 	/* note: a 0-length skb is used as an error indication */
2347 	if (skb->len > 0) {
2348 		skb_checksum_complete_unset(skb);
2349 #ifdef CONFIG_PPP_MULTILINK
2350 		/* XXX do channel-level decompression here */
2351 		if (PPP_PROTO(skb) == PPP_MP)
2352 			ppp_receive_mp_frame(ppp, skb, pch);
2353 		else
2354 #endif /* CONFIG_PPP_MULTILINK */
2355 			ppp_receive_nonmp_frame(ppp, skb);
2356 	} else {
2357 		kfree_skb(skb);
2358 		ppp_receive_error(ppp);
2359 	}
2360 }
2361 
2362 static void
ppp_receive_error(struct ppp * ppp)2363 ppp_receive_error(struct ppp *ppp)
2364 {
2365 	++ppp->dev->stats.rx_errors;
2366 	if (ppp->vj)
2367 		slhc_toss(ppp->vj);
2368 }
2369 
2370 static void
ppp_receive_nonmp_frame(struct ppp * ppp,struct sk_buff * skb)2371 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2372 {
2373 	struct sk_buff *ns;
2374 	int proto, len, npi;
2375 
2376 	/*
2377 	 * Decompress the frame, if compressed.
2378 	 * Note that some decompressors need to see uncompressed frames
2379 	 * that come in as well as compressed frames.
2380 	 */
2381 	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2382 	    (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2383 		skb = ppp_decompress_frame(ppp, skb);
2384 
2385 	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2386 		goto err;
2387 
2388 	/* At this point the "Protocol" field MUST be decompressed, either in
2389 	 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2390 	 */
2391 	proto = PPP_PROTO(skb);
2392 	switch (proto) {
2393 	case PPP_VJC_COMP:
2394 		/* decompress VJ compressed packets */
2395 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2396 			goto err;
2397 
2398 		if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2399 			/* copy to a new sk_buff with more tailroom */
2400 			ns = dev_alloc_skb(skb->len + 128);
2401 			if (!ns) {
2402 				netdev_err(ppp->dev, "PPP: no memory "
2403 					   "(VJ decomp)\n");
2404 				goto err;
2405 			}
2406 			skb_reserve(ns, 2);
2407 			skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2408 			consume_skb(skb);
2409 			skb = ns;
2410 		}
2411 		else
2412 			skb->ip_summed = CHECKSUM_NONE;
2413 
2414 		len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2415 		if (len <= 0) {
2416 			netdev_printk(KERN_DEBUG, ppp->dev,
2417 				      "PPP: VJ decompression error\n");
2418 			goto err;
2419 		}
2420 		len += 2;
2421 		if (len > skb->len)
2422 			skb_put(skb, len - skb->len);
2423 		else if (len < skb->len)
2424 			skb_trim(skb, len);
2425 		proto = PPP_IP;
2426 		break;
2427 
2428 	case PPP_VJC_UNCOMP:
2429 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2430 			goto err;
2431 
2432 		/* Until we fix the decompressor need to make sure
2433 		 * data portion is linear.
2434 		 */
2435 		if (!pskb_may_pull(skb, skb->len))
2436 			goto err;
2437 
2438 		if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2439 			netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2440 			goto err;
2441 		}
2442 		proto = PPP_IP;
2443 		break;
2444 
2445 	case PPP_CCP:
2446 		ppp_ccp_peek(ppp, skb, 1);
2447 		break;
2448 	}
2449 
2450 	++ppp->stats64.rx_packets;
2451 	ppp->stats64.rx_bytes += skb->len - 2;
2452 
2453 	npi = proto_to_npindex(proto);
2454 	if (npi < 0) {
2455 		/* control or unknown frame - pass it to pppd */
2456 		skb_queue_tail(&ppp->file.rq, skb);
2457 		/* limit queue length by dropping old frames */
2458 		while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2459 		       (skb = skb_dequeue(&ppp->file.rq)))
2460 			kfree_skb(skb);
2461 		/* wake up any process polling or blocking on read */
2462 		wake_up_interruptible(&ppp->file.rwait);
2463 
2464 	} else {
2465 		/* network protocol frame - give it to the kernel */
2466 
2467 #ifdef CONFIG_PPP_FILTER
2468 		/* check if the packet passes the pass and active filters */
2469 		/* the filter instructions are constructed assuming
2470 		   a four-byte PPP header on each packet */
2471 		if (ppp->pass_filter || ppp->active_filter) {
2472 			if (skb_unclone(skb, GFP_ATOMIC))
2473 				goto err;
2474 
2475 			*(u8 *)skb_push(skb, 2) = 0;
2476 			if (ppp->pass_filter &&
2477 			    bpf_prog_run(ppp->pass_filter, skb) == 0) {
2478 				if (ppp->debug & 1)
2479 					netdev_printk(KERN_DEBUG, ppp->dev,
2480 						      "PPP: inbound frame "
2481 						      "not passed\n");
2482 				kfree_skb(skb);
2483 				return;
2484 			}
2485 			if (!(ppp->active_filter &&
2486 			      bpf_prog_run(ppp->active_filter, skb) == 0))
2487 				ppp->last_recv = jiffies;
2488 			__skb_pull(skb, 2);
2489 		} else
2490 #endif /* CONFIG_PPP_FILTER */
2491 			ppp->last_recv = jiffies;
2492 
2493 		if ((ppp->dev->flags & IFF_UP) == 0 ||
2494 		    ppp->npmode[npi] != NPMODE_PASS) {
2495 			kfree_skb(skb);
2496 		} else {
2497 			/* chop off protocol */
2498 			skb_pull_rcsum(skb, 2);
2499 			skb->dev = ppp->dev;
2500 			skb->protocol = htons(npindex_to_ethertype[npi]);
2501 			skb_reset_mac_header(skb);
2502 			skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2503 						      dev_net(ppp->dev)));
2504 			netif_rx(skb);
2505 		}
2506 	}
2507 	return;
2508 
2509  err:
2510 	kfree_skb(skb);
2511 	ppp_receive_error(ppp);
2512 }
2513 
2514 static struct sk_buff *
ppp_decompress_frame(struct ppp * ppp,struct sk_buff * skb)2515 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2516 {
2517 	int proto = PPP_PROTO(skb);
2518 	struct sk_buff *ns;
2519 	int len;
2520 
2521 	/* Until we fix all the decompressor's need to make sure
2522 	 * data portion is linear.
2523 	 */
2524 	if (!pskb_may_pull(skb, skb->len))
2525 		goto err;
2526 
2527 	if (proto == PPP_COMP) {
2528 		int obuff_size;
2529 
2530 		switch(ppp->rcomp->compress_proto) {
2531 		case CI_MPPE:
2532 			obuff_size = ppp->mru + PPP_HDRLEN + 1;
2533 			break;
2534 		default:
2535 			obuff_size = ppp->mru + PPP_HDRLEN;
2536 			break;
2537 		}
2538 
2539 		ns = dev_alloc_skb(obuff_size);
2540 		if (!ns) {
2541 			netdev_err(ppp->dev, "ppp_decompress_frame: "
2542 				   "no memory\n");
2543 			goto err;
2544 		}
2545 		/* the decompressor still expects the A/C bytes in the hdr */
2546 		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2547 				skb->len + 2, ns->data, obuff_size);
2548 		if (len < 0) {
2549 			/* Pass the compressed frame to pppd as an
2550 			   error indication. */
2551 			if (len == DECOMP_FATALERROR)
2552 				ppp->rstate |= SC_DC_FERROR;
2553 			kfree_skb(ns);
2554 			goto err;
2555 		}
2556 
2557 		consume_skb(skb);
2558 		skb = ns;
2559 		skb_put(skb, len);
2560 		skb_pull(skb, 2);	/* pull off the A/C bytes */
2561 
2562 		/* Don't call __ppp_decompress_proto() here, but instead rely on
2563 		 * corresponding algo (mppe/bsd/deflate) to decompress it.
2564 		 */
2565 	} else {
2566 		/* Uncompressed frame - pass to decompressor so it
2567 		   can update its dictionary if necessary. */
2568 		if (ppp->rcomp->incomp)
2569 			ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2570 					   skb->len + 2);
2571 	}
2572 
2573 	return skb;
2574 
2575  err:
2576 	ppp->rstate |= SC_DC_ERROR;
2577 	ppp_receive_error(ppp);
2578 	return skb;
2579 }
2580 
2581 #ifdef CONFIG_PPP_MULTILINK
2582 /*
2583  * Receive a multilink frame.
2584  * We put it on the reconstruction queue and then pull off
2585  * as many completed frames as we can.
2586  */
2587 static void
ppp_receive_mp_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2588 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2589 {
2590 	u32 mask, seq;
2591 	struct channel *ch;
2592 	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2593 
2594 	if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2595 		goto err;		/* no good, throw it away */
2596 
2597 	/* Decode sequence number and begin/end bits */
2598 	if (ppp->flags & SC_MP_SHORTSEQ) {
2599 		seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2600 		mask = 0xfff;
2601 	} else {
2602 		seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2603 		mask = 0xffffff;
2604 	}
2605 	PPP_MP_CB(skb)->BEbits = skb->data[2];
2606 	skb_pull(skb, mphdrlen);	/* pull off PPP and MP headers */
2607 
2608 	/*
2609 	 * Do protocol ID decompression on the first fragment of each packet.
2610 	 * We have to do that here, because ppp_receive_nonmp_frame() expects
2611 	 * decompressed protocol field.
2612 	 */
2613 	if (PPP_MP_CB(skb)->BEbits & B)
2614 		__ppp_decompress_proto(skb);
2615 
2616 	/*
2617 	 * Expand sequence number to 32 bits, making it as close
2618 	 * as possible to ppp->minseq.
2619 	 */
2620 	seq |= ppp->minseq & ~mask;
2621 	if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2622 		seq += mask + 1;
2623 	else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2624 		seq -= mask + 1;	/* should never happen */
2625 	PPP_MP_CB(skb)->sequence = seq;
2626 	pch->lastseq = seq;
2627 
2628 	/*
2629 	 * If this packet comes before the next one we were expecting,
2630 	 * drop it.
2631 	 */
2632 	if (seq_before(seq, ppp->nextseq)) {
2633 		kfree_skb(skb);
2634 		++ppp->dev->stats.rx_dropped;
2635 		ppp_receive_error(ppp);
2636 		return;
2637 	}
2638 
2639 	/*
2640 	 * Reevaluate minseq, the minimum over all channels of the
2641 	 * last sequence number received on each channel.  Because of
2642 	 * the increasing sequence number rule, we know that any fragment
2643 	 * before `minseq' which hasn't arrived is never going to arrive.
2644 	 * The list of channels can't change because we have the receive
2645 	 * side of the ppp unit locked.
2646 	 */
2647 	list_for_each_entry(ch, &ppp->channels, clist) {
2648 		if (seq_before(ch->lastseq, seq))
2649 			seq = ch->lastseq;
2650 	}
2651 	if (seq_before(ppp->minseq, seq))
2652 		ppp->minseq = seq;
2653 
2654 	/* Put the fragment on the reconstruction queue */
2655 	ppp_mp_insert(ppp, skb);
2656 
2657 	/* If the queue is getting long, don't wait any longer for packets
2658 	   before the start of the queue. */
2659 	if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2660 		struct sk_buff *mskb = skb_peek(&ppp->mrq);
2661 		if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2662 			ppp->minseq = PPP_MP_CB(mskb)->sequence;
2663 	}
2664 
2665 	/* Pull completed packets off the queue and receive them. */
2666 	while ((skb = ppp_mp_reconstruct(ppp))) {
2667 		if (pskb_may_pull(skb, 2))
2668 			ppp_receive_nonmp_frame(ppp, skb);
2669 		else {
2670 			++ppp->dev->stats.rx_length_errors;
2671 			kfree_skb(skb);
2672 			ppp_receive_error(ppp);
2673 		}
2674 	}
2675 
2676 	return;
2677 
2678  err:
2679 	kfree_skb(skb);
2680 	ppp_receive_error(ppp);
2681 }
2682 
2683 /*
2684  * Insert a fragment on the MP reconstruction queue.
2685  * The queue is ordered by increasing sequence number.
2686  */
2687 static void
ppp_mp_insert(struct ppp * ppp,struct sk_buff * skb)2688 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2689 {
2690 	struct sk_buff *p;
2691 	struct sk_buff_head *list = &ppp->mrq;
2692 	u32 seq = PPP_MP_CB(skb)->sequence;
2693 
2694 	/* N.B. we don't need to lock the list lock because we have the
2695 	   ppp unit receive-side lock. */
2696 	skb_queue_walk(list, p) {
2697 		if (seq_before(seq, PPP_MP_CB(p)->sequence))
2698 			break;
2699 	}
2700 	__skb_queue_before(list, p, skb);
2701 }
2702 
2703 /*
2704  * Reconstruct a packet from the MP fragment queue.
2705  * We go through increasing sequence numbers until we find a
2706  * complete packet, or we get to the sequence number for a fragment
2707  * which hasn't arrived but might still do so.
2708  */
2709 static struct sk_buff *
ppp_mp_reconstruct(struct ppp * ppp)2710 ppp_mp_reconstruct(struct ppp *ppp)
2711 {
2712 	u32 seq = ppp->nextseq;
2713 	u32 minseq = ppp->minseq;
2714 	struct sk_buff_head *list = &ppp->mrq;
2715 	struct sk_buff *p, *tmp;
2716 	struct sk_buff *head, *tail;
2717 	struct sk_buff *skb = NULL;
2718 	int lost = 0, len = 0;
2719 
2720 	if (ppp->mrru == 0)	/* do nothing until mrru is set */
2721 		return NULL;
2722 	head = __skb_peek(list);
2723 	tail = NULL;
2724 	skb_queue_walk_safe(list, p, tmp) {
2725 	again:
2726 		if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2727 			/* this can't happen, anyway ignore the skb */
2728 			netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2729 				   "seq %u < %u\n",
2730 				   PPP_MP_CB(p)->sequence, seq);
2731 			__skb_unlink(p, list);
2732 			kfree_skb(p);
2733 			continue;
2734 		}
2735 		if (PPP_MP_CB(p)->sequence != seq) {
2736 			u32 oldseq;
2737 			/* Fragment `seq' is missing.  If it is after
2738 			   minseq, it might arrive later, so stop here. */
2739 			if (seq_after(seq, minseq))
2740 				break;
2741 			/* Fragment `seq' is lost, keep going. */
2742 			lost = 1;
2743 			oldseq = seq;
2744 			seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2745 				minseq + 1: PPP_MP_CB(p)->sequence;
2746 
2747 			if (ppp->debug & 1)
2748 				netdev_printk(KERN_DEBUG, ppp->dev,
2749 					      "lost frag %u..%u\n",
2750 					      oldseq, seq-1);
2751 
2752 			goto again;
2753 		}
2754 
2755 		/*
2756 		 * At this point we know that all the fragments from
2757 		 * ppp->nextseq to seq are either present or lost.
2758 		 * Also, there are no complete packets in the queue
2759 		 * that have no missing fragments and end before this
2760 		 * fragment.
2761 		 */
2762 
2763 		/* B bit set indicates this fragment starts a packet */
2764 		if (PPP_MP_CB(p)->BEbits & B) {
2765 			head = p;
2766 			lost = 0;
2767 			len = 0;
2768 		}
2769 
2770 		len += p->len;
2771 
2772 		/* Got a complete packet yet? */
2773 		if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2774 		    (PPP_MP_CB(head)->BEbits & B)) {
2775 			if (len > ppp->mrru + 2) {
2776 				++ppp->dev->stats.rx_length_errors;
2777 				netdev_printk(KERN_DEBUG, ppp->dev,
2778 					      "PPP: reconstructed packet"
2779 					      " is too long (%d)\n", len);
2780 			} else {
2781 				tail = p;
2782 				break;
2783 			}
2784 			ppp->nextseq = seq + 1;
2785 		}
2786 
2787 		/*
2788 		 * If this is the ending fragment of a packet,
2789 		 * and we haven't found a complete valid packet yet,
2790 		 * we can discard up to and including this fragment.
2791 		 */
2792 		if (PPP_MP_CB(p)->BEbits & E) {
2793 			struct sk_buff *tmp2;
2794 
2795 			skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2796 				if (ppp->debug & 1)
2797 					netdev_printk(KERN_DEBUG, ppp->dev,
2798 						      "discarding frag %u\n",
2799 						      PPP_MP_CB(p)->sequence);
2800 				__skb_unlink(p, list);
2801 				kfree_skb(p);
2802 			}
2803 			head = skb_peek(list);
2804 			if (!head)
2805 				break;
2806 		}
2807 		++seq;
2808 	}
2809 
2810 	/* If we have a complete packet, copy it all into one skb. */
2811 	if (tail != NULL) {
2812 		/* If we have discarded any fragments,
2813 		   signal a receive error. */
2814 		if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2815 			skb_queue_walk_safe(list, p, tmp) {
2816 				if (p == head)
2817 					break;
2818 				if (ppp->debug & 1)
2819 					netdev_printk(KERN_DEBUG, ppp->dev,
2820 						      "discarding frag %u\n",
2821 						      PPP_MP_CB(p)->sequence);
2822 				__skb_unlink(p, list);
2823 				kfree_skb(p);
2824 			}
2825 
2826 			if (ppp->debug & 1)
2827 				netdev_printk(KERN_DEBUG, ppp->dev,
2828 					      "  missed pkts %u..%u\n",
2829 					      ppp->nextseq,
2830 					      PPP_MP_CB(head)->sequence-1);
2831 			++ppp->dev->stats.rx_dropped;
2832 			ppp_receive_error(ppp);
2833 		}
2834 
2835 		skb = head;
2836 		if (head != tail) {
2837 			struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2838 			p = skb_queue_next(list, head);
2839 			__skb_unlink(skb, list);
2840 			skb_queue_walk_from_safe(list, p, tmp) {
2841 				__skb_unlink(p, list);
2842 				*fragpp = p;
2843 				p->next = NULL;
2844 				fragpp = &p->next;
2845 
2846 				skb->len += p->len;
2847 				skb->data_len += p->len;
2848 				skb->truesize += p->truesize;
2849 
2850 				if (p == tail)
2851 					break;
2852 			}
2853 		} else {
2854 			__skb_unlink(skb, list);
2855 		}
2856 
2857 		ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2858 	}
2859 
2860 	return skb;
2861 }
2862 #endif /* CONFIG_PPP_MULTILINK */
2863 
2864 /*
2865  * Channel interface.
2866  */
2867 
2868 /* Create a new, unattached ppp channel. */
ppp_register_channel(struct ppp_channel * chan)2869 int ppp_register_channel(struct ppp_channel *chan)
2870 {
2871 	return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2872 }
2873 
2874 /* Create a new, unattached ppp channel for specified net. */
ppp_register_net_channel(struct net * net,struct ppp_channel * chan)2875 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2876 {
2877 	struct channel *pch;
2878 	struct ppp_net *pn;
2879 
2880 	pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2881 	if (!pch)
2882 		return -ENOMEM;
2883 
2884 	pn = ppp_pernet(net);
2885 
2886 	pch->ppp = NULL;
2887 	pch->chan = chan;
2888 	pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2889 	chan->ppp = pch;
2890 	init_ppp_file(&pch->file, CHANNEL);
2891 	pch->file.hdrlen = chan->hdrlen;
2892 #ifdef CONFIG_PPP_MULTILINK
2893 	pch->lastseq = -1;
2894 #endif /* CONFIG_PPP_MULTILINK */
2895 	init_rwsem(&pch->chan_sem);
2896 	spin_lock_init(&pch->downl);
2897 	rwlock_init(&pch->upl);
2898 
2899 	spin_lock_bh(&pn->all_channels_lock);
2900 	pch->file.index = ++pn->last_channel_index;
2901 	list_add(&pch->list, &pn->new_channels);
2902 	atomic_inc(&channel_count);
2903 	spin_unlock_bh(&pn->all_channels_lock);
2904 
2905 	return 0;
2906 }
2907 
2908 /*
2909  * Return the index of a channel.
2910  */
ppp_channel_index(struct ppp_channel * chan)2911 int ppp_channel_index(struct ppp_channel *chan)
2912 {
2913 	struct channel *pch = chan->ppp;
2914 
2915 	if (pch)
2916 		return pch->file.index;
2917 	return -1;
2918 }
2919 
2920 /*
2921  * Return the PPP unit number to which a channel is connected.
2922  */
ppp_unit_number(struct ppp_channel * chan)2923 int ppp_unit_number(struct ppp_channel *chan)
2924 {
2925 	struct channel *pch = chan->ppp;
2926 	int unit = -1;
2927 
2928 	if (pch) {
2929 		read_lock_bh(&pch->upl);
2930 		if (pch->ppp)
2931 			unit = pch->ppp->file.index;
2932 		read_unlock_bh(&pch->upl);
2933 	}
2934 	return unit;
2935 }
2936 
2937 /*
2938  * Return the PPP device interface name of a channel.
2939  */
ppp_dev_name(struct ppp_channel * chan)2940 char *ppp_dev_name(struct ppp_channel *chan)
2941 {
2942 	struct channel *pch = chan->ppp;
2943 	char *name = NULL;
2944 
2945 	if (pch) {
2946 		read_lock_bh(&pch->upl);
2947 		if (pch->ppp && pch->ppp->dev)
2948 			name = pch->ppp->dev->name;
2949 		read_unlock_bh(&pch->upl);
2950 	}
2951 	return name;
2952 }
2953 
2954 
2955 /*
2956  * Disconnect a channel from the generic layer.
2957  * This must be called in process context.
2958  */
2959 void
ppp_unregister_channel(struct ppp_channel * chan)2960 ppp_unregister_channel(struct ppp_channel *chan)
2961 {
2962 	struct channel *pch = chan->ppp;
2963 	struct ppp_net *pn;
2964 
2965 	if (!pch)
2966 		return;		/* should never happen */
2967 
2968 	chan->ppp = NULL;
2969 
2970 	/*
2971 	 * This ensures that we have returned from any calls into the
2972 	 * the channel's start_xmit or ioctl routine before we proceed.
2973 	 */
2974 	down_write(&pch->chan_sem);
2975 	spin_lock_bh(&pch->downl);
2976 	pch->chan = NULL;
2977 	spin_unlock_bh(&pch->downl);
2978 	up_write(&pch->chan_sem);
2979 	ppp_disconnect_channel(pch);
2980 
2981 	pn = ppp_pernet(pch->chan_net);
2982 	spin_lock_bh(&pn->all_channels_lock);
2983 	list_del(&pch->list);
2984 	spin_unlock_bh(&pn->all_channels_lock);
2985 
2986 	ppp_unbridge_channels(pch);
2987 
2988 	pch->file.dead = 1;
2989 	wake_up_interruptible(&pch->file.rwait);
2990 
2991 	if (refcount_dec_and_test(&pch->file.refcnt))
2992 		ppp_destroy_channel(pch);
2993 }
2994 
2995 /*
2996  * Callback from a channel when it can accept more to transmit.
2997  * This should be called at BH/softirq level, not interrupt level.
2998  */
2999 void
ppp_output_wakeup(struct ppp_channel * chan)3000 ppp_output_wakeup(struct ppp_channel *chan)
3001 {
3002 	struct channel *pch = chan->ppp;
3003 
3004 	if (!pch)
3005 		return;
3006 	ppp_channel_push(pch);
3007 }
3008 
3009 /*
3010  * Compression control.
3011  */
3012 
3013 /* Process the PPPIOCSCOMPRESS ioctl. */
3014 static int
ppp_set_compress(struct ppp * ppp,struct ppp_option_data * data)3015 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3016 {
3017 	int err = -EFAULT;
3018 	struct compressor *cp, *ocomp;
3019 	void *state, *ostate;
3020 	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3021 
3022 	if (data->length > CCP_MAX_OPTION_LENGTH)
3023 		goto out;
3024 	if (copy_from_user(ccp_option, data->ptr, data->length))
3025 		goto out;
3026 
3027 	err = -EINVAL;
3028 	if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3029 		goto out;
3030 
3031 	cp = try_then_request_module(
3032 		find_compressor(ccp_option[0]),
3033 		"ppp-compress-%d", ccp_option[0]);
3034 	if (!cp)
3035 		goto out;
3036 
3037 	err = -ENOBUFS;
3038 	if (data->transmit) {
3039 		state = cp->comp_alloc(ccp_option, data->length);
3040 		if (state) {
3041 			ppp_xmit_lock(ppp);
3042 			ppp->xstate &= ~SC_COMP_RUN;
3043 			ocomp = ppp->xcomp;
3044 			ostate = ppp->xc_state;
3045 			ppp->xcomp = cp;
3046 			ppp->xc_state = state;
3047 			ppp_xmit_unlock(ppp);
3048 			if (ostate) {
3049 				ocomp->comp_free(ostate);
3050 				module_put(ocomp->owner);
3051 			}
3052 			err = 0;
3053 		} else
3054 			module_put(cp->owner);
3055 
3056 	} else {
3057 		state = cp->decomp_alloc(ccp_option, data->length);
3058 		if (state) {
3059 			ppp_recv_lock(ppp);
3060 			ppp->rstate &= ~SC_DECOMP_RUN;
3061 			ocomp = ppp->rcomp;
3062 			ostate = ppp->rc_state;
3063 			ppp->rcomp = cp;
3064 			ppp->rc_state = state;
3065 			ppp_recv_unlock(ppp);
3066 			if (ostate) {
3067 				ocomp->decomp_free(ostate);
3068 				module_put(ocomp->owner);
3069 			}
3070 			err = 0;
3071 		} else
3072 			module_put(cp->owner);
3073 	}
3074 
3075  out:
3076 	return err;
3077 }
3078 
3079 /*
3080  * Look at a CCP packet and update our state accordingly.
3081  * We assume the caller has the xmit or recv path locked.
3082  */
3083 static void
ppp_ccp_peek(struct ppp * ppp,struct sk_buff * skb,int inbound)3084 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3085 {
3086 	unsigned char *dp;
3087 	int len;
3088 
3089 	if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3090 		return;	/* no header */
3091 	dp = skb->data + 2;
3092 
3093 	switch (CCP_CODE(dp)) {
3094 	case CCP_CONFREQ:
3095 
3096 		/* A ConfReq starts negotiation of compression
3097 		 * in one direction of transmission,
3098 		 * and hence brings it down...but which way?
3099 		 *
3100 		 * Remember:
3101 		 * A ConfReq indicates what the sender would like to receive
3102 		 */
3103 		if(inbound)
3104 			/* He is proposing what I should send */
3105 			ppp->xstate &= ~SC_COMP_RUN;
3106 		else
3107 			/* I am proposing to what he should send */
3108 			ppp->rstate &= ~SC_DECOMP_RUN;
3109 
3110 		break;
3111 
3112 	case CCP_TERMREQ:
3113 	case CCP_TERMACK:
3114 		/*
3115 		 * CCP is going down, both directions of transmission
3116 		 */
3117 		ppp->rstate &= ~SC_DECOMP_RUN;
3118 		ppp->xstate &= ~SC_COMP_RUN;
3119 		break;
3120 
3121 	case CCP_CONFACK:
3122 		if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3123 			break;
3124 		len = CCP_LENGTH(dp);
3125 		if (!pskb_may_pull(skb, len + 2))
3126 			return;		/* too short */
3127 		dp += CCP_HDRLEN;
3128 		len -= CCP_HDRLEN;
3129 		if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3130 			break;
3131 		if (inbound) {
3132 			/* we will start receiving compressed packets */
3133 			if (!ppp->rc_state)
3134 				break;
3135 			if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3136 					ppp->file.index, 0, ppp->mru, ppp->debug)) {
3137 				ppp->rstate |= SC_DECOMP_RUN;
3138 				ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3139 			}
3140 		} else {
3141 			/* we will soon start sending compressed packets */
3142 			if (!ppp->xc_state)
3143 				break;
3144 			if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3145 					ppp->file.index, 0, ppp->debug))
3146 				ppp->xstate |= SC_COMP_RUN;
3147 		}
3148 		break;
3149 
3150 	case CCP_RESETACK:
3151 		/* reset the [de]compressor */
3152 		if ((ppp->flags & SC_CCP_UP) == 0)
3153 			break;
3154 		if (inbound) {
3155 			if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3156 				ppp->rcomp->decomp_reset(ppp->rc_state);
3157 				ppp->rstate &= ~SC_DC_ERROR;
3158 			}
3159 		} else {
3160 			if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3161 				ppp->xcomp->comp_reset(ppp->xc_state);
3162 		}
3163 		break;
3164 	}
3165 }
3166 
3167 /* Free up compression resources. */
3168 static void
ppp_ccp_closed(struct ppp * ppp)3169 ppp_ccp_closed(struct ppp *ppp)
3170 {
3171 	void *xstate, *rstate;
3172 	struct compressor *xcomp, *rcomp;
3173 
3174 	ppp_lock(ppp);
3175 	ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3176 	ppp->xstate = 0;
3177 	xcomp = ppp->xcomp;
3178 	xstate = ppp->xc_state;
3179 	ppp->xc_state = NULL;
3180 	ppp->rstate = 0;
3181 	rcomp = ppp->rcomp;
3182 	rstate = ppp->rc_state;
3183 	ppp->rc_state = NULL;
3184 	ppp_unlock(ppp);
3185 
3186 	if (xstate) {
3187 		xcomp->comp_free(xstate);
3188 		module_put(xcomp->owner);
3189 	}
3190 	if (rstate) {
3191 		rcomp->decomp_free(rstate);
3192 		module_put(rcomp->owner);
3193 	}
3194 }
3195 
3196 /* List of compressors. */
3197 static LIST_HEAD(compressor_list);
3198 static DEFINE_SPINLOCK(compressor_list_lock);
3199 
3200 struct compressor_entry {
3201 	struct list_head list;
3202 	struct compressor *comp;
3203 };
3204 
3205 static struct compressor_entry *
find_comp_entry(int proto)3206 find_comp_entry(int proto)
3207 {
3208 	struct compressor_entry *ce;
3209 
3210 	list_for_each_entry(ce, &compressor_list, list) {
3211 		if (ce->comp->compress_proto == proto)
3212 			return ce;
3213 	}
3214 	return NULL;
3215 }
3216 
3217 /* Register a compressor */
3218 int
ppp_register_compressor(struct compressor * cp)3219 ppp_register_compressor(struct compressor *cp)
3220 {
3221 	struct compressor_entry *ce;
3222 	int ret;
3223 	spin_lock(&compressor_list_lock);
3224 	ret = -EEXIST;
3225 	if (find_comp_entry(cp->compress_proto))
3226 		goto out;
3227 	ret = -ENOMEM;
3228 	ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3229 	if (!ce)
3230 		goto out;
3231 	ret = 0;
3232 	ce->comp = cp;
3233 	list_add(&ce->list, &compressor_list);
3234  out:
3235 	spin_unlock(&compressor_list_lock);
3236 	return ret;
3237 }
3238 
3239 /* Unregister a compressor */
3240 void
ppp_unregister_compressor(struct compressor * cp)3241 ppp_unregister_compressor(struct compressor *cp)
3242 {
3243 	struct compressor_entry *ce;
3244 
3245 	spin_lock(&compressor_list_lock);
3246 	ce = find_comp_entry(cp->compress_proto);
3247 	if (ce && ce->comp == cp) {
3248 		list_del(&ce->list);
3249 		kfree(ce);
3250 	}
3251 	spin_unlock(&compressor_list_lock);
3252 }
3253 
3254 /* Find a compressor. */
3255 static struct compressor *
find_compressor(int type)3256 find_compressor(int type)
3257 {
3258 	struct compressor_entry *ce;
3259 	struct compressor *cp = NULL;
3260 
3261 	spin_lock(&compressor_list_lock);
3262 	ce = find_comp_entry(type);
3263 	if (ce) {
3264 		cp = ce->comp;
3265 		if (!try_module_get(cp->owner))
3266 			cp = NULL;
3267 	}
3268 	spin_unlock(&compressor_list_lock);
3269 	return cp;
3270 }
3271 
3272 /*
3273  * Miscelleneous stuff.
3274  */
3275 
3276 static void
ppp_get_stats(struct ppp * ppp,struct ppp_stats * st)3277 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3278 {
3279 	struct slcompress *vj = ppp->vj;
3280 
3281 	memset(st, 0, sizeof(*st));
3282 	st->p.ppp_ipackets = ppp->stats64.rx_packets;
3283 	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3284 	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3285 	st->p.ppp_opackets = ppp->stats64.tx_packets;
3286 	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3287 	st->p.ppp_obytes = ppp->stats64.tx_bytes;
3288 	if (!vj)
3289 		return;
3290 	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3291 	st->vj.vjs_compressed = vj->sls_o_compressed;
3292 	st->vj.vjs_searches = vj->sls_o_searches;
3293 	st->vj.vjs_misses = vj->sls_o_misses;
3294 	st->vj.vjs_errorin = vj->sls_i_error;
3295 	st->vj.vjs_tossed = vj->sls_i_tossed;
3296 	st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3297 	st->vj.vjs_compressedin = vj->sls_i_compressed;
3298 }
3299 
3300 /*
3301  * Stuff for handling the lists of ppp units and channels
3302  * and for initialization.
3303  */
3304 
3305 /*
3306  * Create a new ppp interface unit.  Fails if it can't allocate memory
3307  * or if there is already a unit with the requested number.
3308  * unit == -1 means allocate a new number.
3309  */
ppp_create_interface(struct net * net,struct file * file,int * unit)3310 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3311 {
3312 	struct ppp_config conf = {
3313 		.file = file,
3314 		.unit = *unit,
3315 		.ifname_is_set = false,
3316 	};
3317 	struct net_device *dev;
3318 	struct ppp *ppp;
3319 	int err;
3320 
3321 	dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3322 	if (!dev) {
3323 		err = -ENOMEM;
3324 		goto err;
3325 	}
3326 	dev_net_set(dev, net);
3327 	dev->rtnl_link_ops = &ppp_link_ops;
3328 
3329 	rtnl_lock();
3330 
3331 	err = ppp_dev_configure(net, dev, &conf);
3332 	if (err < 0)
3333 		goto err_dev;
3334 	ppp = netdev_priv(dev);
3335 	*unit = ppp->file.index;
3336 
3337 	rtnl_unlock();
3338 
3339 	return 0;
3340 
3341 err_dev:
3342 	rtnl_unlock();
3343 	free_netdev(dev);
3344 err:
3345 	return err;
3346 }
3347 
3348 /*
3349  * Initialize a ppp_file structure.
3350  */
3351 static void
init_ppp_file(struct ppp_file * pf,int kind)3352 init_ppp_file(struct ppp_file *pf, int kind)
3353 {
3354 	pf->kind = kind;
3355 	skb_queue_head_init(&pf->xq);
3356 	skb_queue_head_init(&pf->rq);
3357 	refcount_set(&pf->refcnt, 1);
3358 	init_waitqueue_head(&pf->rwait);
3359 }
3360 
3361 /*
3362  * Free the memory used by a ppp unit.  This is only called once
3363  * there are no channels connected to the unit and no file structs
3364  * that reference the unit.
3365  */
ppp_destroy_interface(struct ppp * ppp)3366 static void ppp_destroy_interface(struct ppp *ppp)
3367 {
3368 	atomic_dec(&ppp_unit_count);
3369 
3370 	if (!ppp->file.dead || ppp->n_channels) {
3371 		/* "can't happen" */
3372 		netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3373 			   "but dead=%d n_channels=%d !\n",
3374 			   ppp, ppp->file.dead, ppp->n_channels);
3375 		return;
3376 	}
3377 
3378 	ppp_ccp_closed(ppp);
3379 	if (ppp->vj) {
3380 		slhc_free(ppp->vj);
3381 		ppp->vj = NULL;
3382 	}
3383 	skb_queue_purge(&ppp->file.xq);
3384 	skb_queue_purge(&ppp->file.rq);
3385 #ifdef CONFIG_PPP_MULTILINK
3386 	skb_queue_purge(&ppp->mrq);
3387 #endif /* CONFIG_PPP_MULTILINK */
3388 #ifdef CONFIG_PPP_FILTER
3389 	if (ppp->pass_filter) {
3390 		bpf_prog_destroy(ppp->pass_filter);
3391 		ppp->pass_filter = NULL;
3392 	}
3393 
3394 	if (ppp->active_filter) {
3395 		bpf_prog_destroy(ppp->active_filter);
3396 		ppp->active_filter = NULL;
3397 	}
3398 #endif /* CONFIG_PPP_FILTER */
3399 
3400 	kfree_skb(ppp->xmit_pending);
3401 	free_percpu(ppp->xmit_recursion);
3402 
3403 	free_netdev(ppp->dev);
3404 }
3405 
3406 /*
3407  * Locate an existing ppp unit.
3408  * The caller should have locked the all_ppp_mutex.
3409  */
3410 static struct ppp *
ppp_find_unit(struct ppp_net * pn,int unit)3411 ppp_find_unit(struct ppp_net *pn, int unit)
3412 {
3413 	return unit_find(&pn->units_idr, unit);
3414 }
3415 
3416 /*
3417  * Locate an existing ppp channel.
3418  * The caller should have locked the all_channels_lock.
3419  * First we look in the new_channels list, then in the
3420  * all_channels list.  If found in the new_channels list,
3421  * we move it to the all_channels list.  This is for speed
3422  * when we have a lot of channels in use.
3423  */
3424 static struct channel *
ppp_find_channel(struct ppp_net * pn,int unit)3425 ppp_find_channel(struct ppp_net *pn, int unit)
3426 {
3427 	struct channel *pch;
3428 
3429 	list_for_each_entry(pch, &pn->new_channels, list) {
3430 		if (pch->file.index == unit) {
3431 			list_move(&pch->list, &pn->all_channels);
3432 			return pch;
3433 		}
3434 	}
3435 
3436 	list_for_each_entry(pch, &pn->all_channels, list) {
3437 		if (pch->file.index == unit)
3438 			return pch;
3439 	}
3440 
3441 	return NULL;
3442 }
3443 
3444 /*
3445  * Connect a PPP channel to a PPP interface unit.
3446  */
3447 static int
ppp_connect_channel(struct channel * pch,int unit)3448 ppp_connect_channel(struct channel *pch, int unit)
3449 {
3450 	struct ppp *ppp;
3451 	struct ppp_net *pn;
3452 	int ret = -ENXIO;
3453 	int hdrlen;
3454 
3455 	pn = ppp_pernet(pch->chan_net);
3456 
3457 	mutex_lock(&pn->all_ppp_mutex);
3458 	ppp = ppp_find_unit(pn, unit);
3459 	if (!ppp)
3460 		goto out;
3461 	write_lock_bh(&pch->upl);
3462 	ret = -EINVAL;
3463 	if (pch->ppp ||
3464 	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3465 		goto outl;
3466 
3467 	ppp_lock(ppp);
3468 	spin_lock_bh(&pch->downl);
3469 	if (!pch->chan) {
3470 		/* Don't connect unregistered channels */
3471 		spin_unlock_bh(&pch->downl);
3472 		ppp_unlock(ppp);
3473 		ret = -ENOTCONN;
3474 		goto outl;
3475 	}
3476 	spin_unlock_bh(&pch->downl);
3477 	if (pch->file.hdrlen > ppp->file.hdrlen)
3478 		ppp->file.hdrlen = pch->file.hdrlen;
3479 	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
3480 	if (hdrlen > ppp->dev->hard_header_len)
3481 		ppp->dev->hard_header_len = hdrlen;
3482 	list_add_tail(&pch->clist, &ppp->channels);
3483 	++ppp->n_channels;
3484 	pch->ppp = ppp;
3485 	refcount_inc(&ppp->file.refcnt);
3486 	ppp_unlock(ppp);
3487 	ret = 0;
3488 
3489  outl:
3490 	write_unlock_bh(&pch->upl);
3491  out:
3492 	mutex_unlock(&pn->all_ppp_mutex);
3493 	return ret;
3494 }
3495 
3496 /*
3497  * Disconnect a channel from its ppp unit.
3498  */
3499 static int
ppp_disconnect_channel(struct channel * pch)3500 ppp_disconnect_channel(struct channel *pch)
3501 {
3502 	struct ppp *ppp;
3503 	int err = -EINVAL;
3504 
3505 	write_lock_bh(&pch->upl);
3506 	ppp = pch->ppp;
3507 	pch->ppp = NULL;
3508 	write_unlock_bh(&pch->upl);
3509 	if (ppp) {
3510 		/* remove it from the ppp unit's list */
3511 		ppp_lock(ppp);
3512 		list_del(&pch->clist);
3513 		if (--ppp->n_channels == 0)
3514 			wake_up_interruptible(&ppp->file.rwait);
3515 		ppp_unlock(ppp);
3516 		if (refcount_dec_and_test(&ppp->file.refcnt))
3517 			ppp_destroy_interface(ppp);
3518 		err = 0;
3519 	}
3520 	return err;
3521 }
3522 
3523 /*
3524  * Free up the resources used by a ppp channel.
3525  */
ppp_destroy_channel(struct channel * pch)3526 static void ppp_destroy_channel(struct channel *pch)
3527 {
3528 	put_net_track(pch->chan_net, &pch->ns_tracker);
3529 	pch->chan_net = NULL;
3530 
3531 	atomic_dec(&channel_count);
3532 
3533 	if (!pch->file.dead) {
3534 		/* "can't happen" */
3535 		pr_err("ppp: destroying undead channel %p !\n", pch);
3536 		return;
3537 	}
3538 	skb_queue_purge(&pch->file.xq);
3539 	skb_queue_purge(&pch->file.rq);
3540 	kfree(pch);
3541 }
3542 
ppp_cleanup(void)3543 static void __exit ppp_cleanup(void)
3544 {
3545 	/* should never happen */
3546 	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3547 		pr_err("PPP: removing module but units remain!\n");
3548 	rtnl_link_unregister(&ppp_link_ops);
3549 	unregister_chrdev(PPP_MAJOR, "ppp");
3550 	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3551 	class_destroy(ppp_class);
3552 	unregister_pernet_device(&ppp_net_ops);
3553 }
3554 
3555 /*
3556  * Units handling. Caller must protect concurrent access
3557  * by holding all_ppp_mutex
3558  */
3559 
3560 /* associate pointer with specified number */
unit_set(struct idr * p,void * ptr,int n)3561 static int unit_set(struct idr *p, void *ptr, int n)
3562 {
3563 	int unit;
3564 
3565 	unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3566 	if (unit == -ENOSPC)
3567 		unit = -EINVAL;
3568 	return unit;
3569 }
3570 
3571 /* get new free unit number and associate pointer with it */
unit_get(struct idr * p,void * ptr,int min)3572 static int unit_get(struct idr *p, void *ptr, int min)
3573 {
3574 	return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3575 }
3576 
3577 /* put unit number back to a pool */
unit_put(struct idr * p,int n)3578 static void unit_put(struct idr *p, int n)
3579 {
3580 	idr_remove(p, n);
3581 }
3582 
3583 /* get pointer associated with the number */
unit_find(struct idr * p,int n)3584 static void *unit_find(struct idr *p, int n)
3585 {
3586 	return idr_find(p, n);
3587 }
3588 
3589 /* Module/initialization stuff */
3590 
3591 module_init(ppp_init);
3592 module_exit(ppp_cleanup);
3593 
3594 EXPORT_SYMBOL(ppp_register_net_channel);
3595 EXPORT_SYMBOL(ppp_register_channel);
3596 EXPORT_SYMBOL(ppp_unregister_channel);
3597 EXPORT_SYMBOL(ppp_channel_index);
3598 EXPORT_SYMBOL(ppp_unit_number);
3599 EXPORT_SYMBOL(ppp_dev_name);
3600 EXPORT_SYMBOL(ppp_input);
3601 EXPORT_SYMBOL(ppp_input_error);
3602 EXPORT_SYMBOL(ppp_output_wakeup);
3603 EXPORT_SYMBOL(ppp_register_compressor);
3604 EXPORT_SYMBOL(ppp_unregister_compressor);
3605 MODULE_LICENSE("GPL");
3606 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3607 MODULE_ALIAS_RTNL_LINK("ppp");
3608 MODULE_ALIAS("devname:ppp");
3609