xref: /linux/drivers/net/ppp/ppp_generic.c (revision 8c245fe7dde3bf776253550fc914a36293db4ff3)
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 <linux/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 #define PPP_LCP_HDRLEN	4
74 
75 /*
76  * An instance of /dev/ppp can be associated with either a ppp
77  * interface unit or a ppp channel.  In both cases, file->private_data
78  * points to one of these.
79  */
80 struct ppp_file {
81 	enum {
82 		INTERFACE=1, CHANNEL
83 	}		kind;
84 	struct sk_buff_head xq;		/* pppd transmit queue */
85 	struct sk_buff_head rq;		/* receive queue for pppd */
86 	wait_queue_head_t rwait;	/* for poll on reading /dev/ppp */
87 	refcount_t	refcnt;		/* # refs (incl /dev/ppp attached) */
88 	int		hdrlen;		/* space to leave for headers */
89 	int		index;		/* interface unit / channel number */
90 	int		dead;		/* unit/channel has been shut down */
91 };
92 
93 #define PF_TO_X(pf, X)		container_of(pf, X, file)
94 
95 #define PF_TO_PPP(pf)		PF_TO_X(pf, struct ppp)
96 #define PF_TO_CHANNEL(pf)	PF_TO_X(pf, struct channel)
97 
98 /*
99  * Data structure to hold primary network stats for which
100  * we want to use 64 bit storage.  Other network stats
101  * are stored in dev->stats of the ppp strucute.
102  */
103 struct ppp_link_stats {
104 	u64 rx_packets;
105 	u64 tx_packets;
106 	u64 rx_bytes;
107 	u64 tx_bytes;
108 };
109 
110 /*
111  * Data structure describing one ppp unit.
112  * A ppp unit corresponds to a ppp network interface device
113  * and represents a multilink bundle.
114  * It can have 0 or more ppp channels connected to it.
115  */
116 struct ppp {
117 	struct ppp_file	file;		/* stuff for read/write/poll 0 */
118 	struct file	*owner;		/* file that owns this unit 48 */
119 	struct list_head channels;	/* list of attached channels 4c */
120 	int		n_channels;	/* how many channels are attached 54 */
121 	spinlock_t	rlock;		/* lock for receive side 58 */
122 	spinlock_t	wlock;		/* lock for transmit side 5c */
123 	int __percpu	*xmit_recursion; /* xmit recursion detect */
124 	int		mru;		/* max receive unit 60 */
125 	unsigned int	flags;		/* control bits 64 */
126 	unsigned int	xstate;		/* transmit state bits 68 */
127 	unsigned int	rstate;		/* receive state bits 6c */
128 	int		debug;		/* debug flags 70 */
129 	struct slcompress *vj;		/* state for VJ header compression */
130 	enum NPmode	npmode[NUM_NP];	/* what to do with each net proto 78 */
131 	struct sk_buff	*xmit_pending;	/* a packet ready to go out 88 */
132 	struct compressor *xcomp;	/* transmit packet compressor 8c */
133 	void		*xc_state;	/* its internal state 90 */
134 	struct compressor *rcomp;	/* receive decompressor 94 */
135 	void		*rc_state;	/* its internal state 98 */
136 	unsigned long	last_xmit;	/* jiffies when last pkt sent 9c */
137 	unsigned long	last_recv;	/* jiffies when last pkt rcvd a0 */
138 	struct net_device *dev;		/* network interface device a4 */
139 	int		closing;	/* is device closing down? a8 */
140 #ifdef CONFIG_PPP_MULTILINK
141 	int		nxchan;		/* next channel to send something on */
142 	u32		nxseq;		/* next sequence number to send */
143 	int		mrru;		/* MP: max reconst. receive unit */
144 	u32		nextseq;	/* MP: seq no of next packet */
145 	u32		minseq;		/* MP: min of most recent seqnos */
146 	struct sk_buff_head mrq;	/* MP: receive reconstruction queue */
147 #endif /* CONFIG_PPP_MULTILINK */
148 #ifdef CONFIG_PPP_FILTER
149 	struct bpf_prog *pass_filter;	/* filter for packets to pass */
150 	struct bpf_prog *active_filter; /* filter for pkts to reset idle */
151 #endif /* CONFIG_PPP_FILTER */
152 	struct net	*ppp_net;	/* the net we belong to */
153 	struct ppp_link_stats stats64;	/* 64 bit network stats */
154 };
155 
156 /*
157  * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
158  * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
159  * SC_MUST_COMP
160  * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
161  * Bits in xstate: SC_COMP_RUN
162  */
163 #define SC_FLAG_BITS	(SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
164 			 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
165 			 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
166 
167 /*
168  * Private data structure for each channel.
169  * This includes the data structure used for multilink.
170  */
171 struct channel {
172 	struct ppp_file	file;		/* stuff for read/write/poll */
173 	struct list_head list;		/* link in all/new_channels list */
174 	struct ppp_channel *chan;	/* public channel data structure */
175 	struct rw_semaphore chan_sem;	/* protects `chan' during chan ioctl */
176 	spinlock_t	downl;		/* protects `chan', file.xq dequeue */
177 	struct ppp	*ppp;		/* ppp unit we're connected to */
178 	struct net	*chan_net;	/* the net channel belongs to */
179 	netns_tracker	ns_tracker;
180 	struct list_head clist;		/* link in list of channels per unit */
181 	rwlock_t	upl;		/* protects `ppp' and 'bridge' */
182 	struct channel __rcu *bridge;	/* "bridged" ppp channel */
183 #ifdef CONFIG_PPP_MULTILINK
184 	u8		avail;		/* flag used in multilink stuff */
185 	u8		had_frag;	/* >= 1 fragments have been sent */
186 	u32		lastseq;	/* MP: last sequence # received */
187 	int		speed;		/* speed of the corresponding ppp channel*/
188 #endif /* CONFIG_PPP_MULTILINK */
189 };
190 
191 struct ppp_config {
192 	struct file *file;
193 	s32 unit;
194 	bool ifname_is_set;
195 };
196 
197 /*
198  * SMP locking issues:
199  * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
200  * list and the ppp.n_channels field, you need to take both locks
201  * before you modify them.
202  * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
203  * channel.downl.
204  */
205 
206 static DEFINE_MUTEX(ppp_mutex);
207 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
208 static atomic_t channel_count = ATOMIC_INIT(0);
209 
210 /* per-net private data for this module */
211 static unsigned int ppp_net_id __read_mostly;
212 struct ppp_net {
213 	/* units to ppp mapping */
214 	struct idr units_idr;
215 
216 	/*
217 	 * all_ppp_mutex protects the units_idr mapping.
218 	 * It also ensures that finding a ppp unit in the units_idr
219 	 * map and updating its file.refcnt field is atomic.
220 	 */
221 	struct mutex all_ppp_mutex;
222 
223 	/* channels */
224 	struct list_head all_channels;
225 	struct list_head new_channels;
226 	int last_channel_index;
227 
228 	/*
229 	 * all_channels_lock protects all_channels and
230 	 * last_channel_index, and the atomicity of find
231 	 * a channel and updating its file.refcnt field.
232 	 */
233 	spinlock_t all_channels_lock;
234 };
235 
236 /* Get the PPP protocol number from a skb */
237 #define PPP_PROTO(skb)	get_unaligned_be16((skb)->data)
238 
239 /* We limit the length of ppp->file.rq to this (arbitrary) value */
240 #define PPP_MAX_RQLEN	32
241 
242 /*
243  * Maximum number of multilink fragments queued up.
244  * This has to be large enough to cope with the maximum latency of
245  * the slowest channel relative to the others.  Strictly it should
246  * depend on the number of channels and their characteristics.
247  */
248 #define PPP_MP_MAX_QLEN	128
249 
250 /* Multilink header bits. */
251 #define B	0x80		/* this fragment begins a packet */
252 #define E	0x40		/* this fragment ends a packet */
253 
254 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
255 #define seq_before(a, b)	((s32)((a) - (b)) < 0)
256 #define seq_after(a, b)		((s32)((a) - (b)) > 0)
257 
258 /* Prototypes. */
259 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
260 			struct file *file, unsigned int cmd, unsigned long arg);
261 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
262 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
263 static void ppp_push(struct ppp *ppp);
264 static void ppp_channel_push(struct channel *pch);
265 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
266 			      struct channel *pch);
267 static void ppp_receive_error(struct ppp *ppp);
268 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
269 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
270 					    struct sk_buff *skb);
271 #ifdef CONFIG_PPP_MULTILINK
272 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
273 				struct channel *pch);
274 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
275 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
276 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
277 #endif /* CONFIG_PPP_MULTILINK */
278 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
279 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
280 static void ppp_ccp_closed(struct ppp *ppp);
281 static struct compressor *find_compressor(int type);
282 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
283 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
284 static void init_ppp_file(struct ppp_file *pf, int kind);
285 static void ppp_destroy_interface(struct ppp *ppp);
286 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
287 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
288 static int ppp_connect_channel(struct channel *pch, int unit);
289 static int ppp_disconnect_channel(struct channel *pch);
290 static void ppp_destroy_channel(struct channel *pch);
291 static int unit_get(struct idr *p, void *ptr, int min);
292 static int unit_set(struct idr *p, void *ptr, int n);
293 static void unit_put(struct idr *p, int n);
294 static void *unit_find(struct idr *p, int n);
295 static void ppp_setup(struct net_device *dev);
296 
297 static const struct net_device_ops ppp_netdev_ops;
298 
299 static const struct class ppp_class = {
300 	.name = "ppp",
301 };
302 
303 /* per net-namespace data */
ppp_pernet(struct net * net)304 static inline struct ppp_net *ppp_pernet(struct net *net)
305 {
306 	return net_generic(net, ppp_net_id);
307 }
308 
309 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)310 static inline int proto_to_npindex(int proto)
311 {
312 	switch (proto) {
313 	case PPP_IP:
314 		return NP_IP;
315 	case PPP_IPV6:
316 		return NP_IPV6;
317 	case PPP_IPX:
318 		return NP_IPX;
319 	case PPP_AT:
320 		return NP_AT;
321 	case PPP_MPLS_UC:
322 		return NP_MPLS_UC;
323 	case PPP_MPLS_MC:
324 		return NP_MPLS_MC;
325 	}
326 	return -EINVAL;
327 }
328 
329 /* Translates an NP index into a PPP protocol number */
330 static const int npindex_to_proto[NUM_NP] = {
331 	PPP_IP,
332 	PPP_IPV6,
333 	PPP_IPX,
334 	PPP_AT,
335 	PPP_MPLS_UC,
336 	PPP_MPLS_MC,
337 };
338 
339 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)340 static inline int ethertype_to_npindex(int ethertype)
341 {
342 	switch (ethertype) {
343 	case ETH_P_IP:
344 		return NP_IP;
345 	case ETH_P_IPV6:
346 		return NP_IPV6;
347 	case ETH_P_IPX:
348 		return NP_IPX;
349 	case ETH_P_PPPTALK:
350 	case ETH_P_ATALK:
351 		return NP_AT;
352 	case ETH_P_MPLS_UC:
353 		return NP_MPLS_UC;
354 	case ETH_P_MPLS_MC:
355 		return NP_MPLS_MC;
356 	}
357 	return -1;
358 }
359 
360 /* Translates an NP index into an ethertype */
361 static const int npindex_to_ethertype[NUM_NP] = {
362 	ETH_P_IP,
363 	ETH_P_IPV6,
364 	ETH_P_IPX,
365 	ETH_P_PPPTALK,
366 	ETH_P_MPLS_UC,
367 	ETH_P_MPLS_MC,
368 };
369 
370 /*
371  * Locking shorthand.
372  */
373 #define ppp_xmit_lock(ppp)	spin_lock_bh(&(ppp)->wlock)
374 #define ppp_xmit_unlock(ppp)	spin_unlock_bh(&(ppp)->wlock)
375 #define ppp_recv_lock(ppp)	spin_lock_bh(&(ppp)->rlock)
376 #define ppp_recv_unlock(ppp)	spin_unlock_bh(&(ppp)->rlock)
377 #define ppp_lock(ppp)		do { ppp_xmit_lock(ppp); \
378 				     ppp_recv_lock(ppp); } while (0)
379 #define ppp_unlock(ppp)		do { ppp_recv_unlock(ppp); \
380 				     ppp_xmit_unlock(ppp); } while (0)
381 
382 /*
383  * /dev/ppp device routines.
384  * The /dev/ppp device is used by pppd to control the ppp unit.
385  * It supports the read, write, ioctl and poll functions.
386  * Open instances of /dev/ppp can be in one of three states:
387  * unattached, attached to a ppp unit, or attached to a ppp channel.
388  */
ppp_open(struct inode * inode,struct file * file)389 static int ppp_open(struct inode *inode, struct file *file)
390 {
391 	/*
392 	 * This could (should?) be enforced by the permissions on /dev/ppp.
393 	 */
394 	if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
395 		return -EPERM;
396 	return 0;
397 }
398 
ppp_release(struct inode * unused,struct file * file)399 static int ppp_release(struct inode *unused, struct file *file)
400 {
401 	struct ppp_file *pf = file->private_data;
402 	struct ppp *ppp;
403 
404 	if (pf) {
405 		file->private_data = NULL;
406 		if (pf->kind == INTERFACE) {
407 			ppp = PF_TO_PPP(pf);
408 			rtnl_lock();
409 			if (file == ppp->owner)
410 				unregister_netdevice(ppp->dev);
411 			rtnl_unlock();
412 		}
413 		if (refcount_dec_and_test(&pf->refcnt)) {
414 			switch (pf->kind) {
415 			case INTERFACE:
416 				ppp_destroy_interface(PF_TO_PPP(pf));
417 				break;
418 			case CHANNEL:
419 				ppp_destroy_channel(PF_TO_CHANNEL(pf));
420 				break;
421 			}
422 		}
423 	}
424 	return 0;
425 }
426 
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)427 static ssize_t ppp_read(struct file *file, char __user *buf,
428 			size_t count, loff_t *ppos)
429 {
430 	struct ppp_file *pf = file->private_data;
431 	DECLARE_WAITQUEUE(wait, current);
432 	ssize_t ret;
433 	struct sk_buff *skb = NULL;
434 	struct iovec iov;
435 	struct iov_iter to;
436 
437 	ret = count;
438 
439 	if (!pf)
440 		return -ENXIO;
441 	add_wait_queue(&pf->rwait, &wait);
442 	for (;;) {
443 		set_current_state(TASK_INTERRUPTIBLE);
444 		skb = skb_dequeue(&pf->rq);
445 		if (skb)
446 			break;
447 		ret = 0;
448 		if (pf->dead)
449 			break;
450 		if (pf->kind == INTERFACE) {
451 			/*
452 			 * Return 0 (EOF) on an interface that has no
453 			 * channels connected, unless it is looping
454 			 * network traffic (demand mode).
455 			 */
456 			struct ppp *ppp = PF_TO_PPP(pf);
457 
458 			ppp_recv_lock(ppp);
459 			if (ppp->n_channels == 0 &&
460 			    (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
461 				ppp_recv_unlock(ppp);
462 				break;
463 			}
464 			ppp_recv_unlock(ppp);
465 		}
466 		ret = -EAGAIN;
467 		if (file->f_flags & O_NONBLOCK)
468 			break;
469 		ret = -ERESTARTSYS;
470 		if (signal_pending(current))
471 			break;
472 		schedule();
473 	}
474 	set_current_state(TASK_RUNNING);
475 	remove_wait_queue(&pf->rwait, &wait);
476 
477 	if (!skb)
478 		goto out;
479 
480 	ret = -EOVERFLOW;
481 	if (skb->len > count)
482 		goto outf;
483 	ret = -EFAULT;
484 	iov.iov_base = buf;
485 	iov.iov_len = count;
486 	iov_iter_init(&to, ITER_DEST, &iov, 1, count);
487 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
488 		goto outf;
489 	ret = skb->len;
490 
491  outf:
492 	kfree_skb(skb);
493  out:
494 	return ret;
495 }
496 
ppp_check_packet(struct sk_buff * skb,size_t count)497 static bool ppp_check_packet(struct sk_buff *skb, size_t count)
498 {
499 	/* LCP packets must include LCP header which 4 bytes long:
500 	 * 1-byte code, 1-byte identifier, and 2-byte length.
501 	 */
502 	return get_unaligned_be16(skb->data) != PPP_LCP ||
503 		count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
504 }
505 
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)506 static ssize_t ppp_write(struct file *file, const char __user *buf,
507 			 size_t count, loff_t *ppos)
508 {
509 	struct ppp_file *pf = file->private_data;
510 	struct sk_buff *skb;
511 	ssize_t ret;
512 
513 	if (!pf)
514 		return -ENXIO;
515 	/* All PPP packets should start with the 2-byte protocol */
516 	if (count < PPP_PROTO_LEN)
517 		return -EINVAL;
518 	ret = -ENOMEM;
519 	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
520 	if (!skb)
521 		goto out;
522 	skb_reserve(skb, pf->hdrlen);
523 	ret = -EFAULT;
524 	if (copy_from_user(skb_put(skb, count), buf, count)) {
525 		kfree_skb(skb);
526 		goto out;
527 	}
528 	ret = -EINVAL;
529 	if (unlikely(!ppp_check_packet(skb, count))) {
530 		kfree_skb(skb);
531 		goto out;
532 	}
533 
534 	switch (pf->kind) {
535 	case INTERFACE:
536 		ppp_xmit_process(PF_TO_PPP(pf), skb);
537 		break;
538 	case CHANNEL:
539 		skb_queue_tail(&pf->xq, skb);
540 		ppp_channel_push(PF_TO_CHANNEL(pf));
541 		break;
542 	}
543 
544 	ret = count;
545 
546  out:
547 	return ret;
548 }
549 
550 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)551 static __poll_t ppp_poll(struct file *file, poll_table *wait)
552 {
553 	struct ppp_file *pf = file->private_data;
554 	__poll_t mask;
555 
556 	if (!pf)
557 		return 0;
558 	poll_wait(file, &pf->rwait, wait);
559 	mask = EPOLLOUT | EPOLLWRNORM;
560 	if (skb_peek(&pf->rq))
561 		mask |= EPOLLIN | EPOLLRDNORM;
562 	if (pf->dead)
563 		mask |= EPOLLHUP;
564 	else if (pf->kind == INTERFACE) {
565 		/* see comment in ppp_read */
566 		struct ppp *ppp = PF_TO_PPP(pf);
567 
568 		ppp_recv_lock(ppp);
569 		if (ppp->n_channels == 0 &&
570 		    (ppp->flags & SC_LOOP_TRAFFIC) == 0)
571 			mask |= EPOLLIN | EPOLLRDNORM;
572 		ppp_recv_unlock(ppp);
573 	}
574 
575 	return mask;
576 }
577 
578 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)579 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
580 {
581 	struct sock_fprog_kern fprog;
582 	struct bpf_prog *res = NULL;
583 	int err;
584 
585 	if (!uprog->len)
586 		return NULL;
587 
588 	/* uprog->len is unsigned short, so no overflow here */
589 	fprog.len = uprog->len;
590 	fprog.filter = memdup_array_user(uprog->filter,
591 					 uprog->len, sizeof(struct sock_filter));
592 	if (IS_ERR(fprog.filter))
593 		return ERR_CAST(fprog.filter);
594 
595 	err = bpf_prog_create(&res, &fprog);
596 	kfree(fprog.filter);
597 
598 	return err ? ERR_PTR(err) : res;
599 }
600 
ppp_get_filter(struct sock_fprog __user * p)601 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
602 {
603 	struct sock_fprog uprog;
604 
605 	if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
606 		return ERR_PTR(-EFAULT);
607 	return get_filter(&uprog);
608 }
609 
610 #ifdef CONFIG_COMPAT
611 struct sock_fprog32 {
612 	unsigned short len;
613 	compat_caddr_t filter;
614 };
615 
616 #define PPPIOCSPASS32		_IOW('t', 71, struct sock_fprog32)
617 #define PPPIOCSACTIVE32		_IOW('t', 70, struct sock_fprog32)
618 
compat_ppp_get_filter(struct sock_fprog32 __user * p)619 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
620 {
621 	struct sock_fprog32 uprog32;
622 	struct sock_fprog uprog;
623 
624 	if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
625 		return ERR_PTR(-EFAULT);
626 	uprog.len = uprog32.len;
627 	uprog.filter = compat_ptr(uprog32.filter);
628 	return get_filter(&uprog);
629 }
630 #endif
631 #endif
632 
633 /* Bridge one PPP channel to another.
634  * When two channels are bridged, ppp_input on one channel is redirected to
635  * the other's ops->start_xmit handler.
636  * In order to safely bridge channels we must reject channels which are already
637  * part of a bridge instance, or which form part of an existing unit.
638  * Once successfully bridged, each channel holds a reference on the other
639  * to prevent it being freed while the bridge is extant.
640  */
ppp_bridge_channels(struct channel * pch,struct channel * pchb)641 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
642 {
643 	write_lock_bh(&pch->upl);
644 	if (pch->ppp ||
645 	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
646 		write_unlock_bh(&pch->upl);
647 		return -EALREADY;
648 	}
649 	refcount_inc(&pchb->file.refcnt);
650 	rcu_assign_pointer(pch->bridge, pchb);
651 	write_unlock_bh(&pch->upl);
652 
653 	write_lock_bh(&pchb->upl);
654 	if (pchb->ppp ||
655 	    rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
656 		write_unlock_bh(&pchb->upl);
657 		goto err_unset;
658 	}
659 	refcount_inc(&pch->file.refcnt);
660 	rcu_assign_pointer(pchb->bridge, pch);
661 	write_unlock_bh(&pchb->upl);
662 
663 	return 0;
664 
665 err_unset:
666 	write_lock_bh(&pch->upl);
667 	/* Re-read pch->bridge with upl held in case it was modified concurrently */
668 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
669 	RCU_INIT_POINTER(pch->bridge, NULL);
670 	write_unlock_bh(&pch->upl);
671 	synchronize_rcu();
672 
673 	if (pchb)
674 		if (refcount_dec_and_test(&pchb->file.refcnt))
675 			ppp_destroy_channel(pchb);
676 
677 	return -EALREADY;
678 }
679 
ppp_unbridge_channels(struct channel * pch)680 static int ppp_unbridge_channels(struct channel *pch)
681 {
682 	struct channel *pchb, *pchbb;
683 
684 	write_lock_bh(&pch->upl);
685 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
686 	if (!pchb) {
687 		write_unlock_bh(&pch->upl);
688 		return -EINVAL;
689 	}
690 	RCU_INIT_POINTER(pch->bridge, NULL);
691 	write_unlock_bh(&pch->upl);
692 
693 	/* Only modify pchb if phcb->bridge points back to pch.
694 	 * If not, it implies that there has been a race unbridging (and possibly
695 	 * even rebridging) pchb.  We should leave pchb alone to avoid either a
696 	 * refcount underflow, or breaking another established bridge instance.
697 	 */
698 	write_lock_bh(&pchb->upl);
699 	pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
700 	if (pchbb == pch)
701 		RCU_INIT_POINTER(pchb->bridge, NULL);
702 	write_unlock_bh(&pchb->upl);
703 
704 	synchronize_rcu();
705 
706 	if (pchbb == pch)
707 		if (refcount_dec_and_test(&pch->file.refcnt))
708 			ppp_destroy_channel(pch);
709 
710 	if (refcount_dec_and_test(&pchb->file.refcnt))
711 		ppp_destroy_channel(pchb);
712 
713 	return 0;
714 }
715 
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)716 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
717 {
718 	struct ppp_file *pf;
719 	struct ppp *ppp;
720 	int err = -EFAULT, val, val2, i;
721 	struct ppp_idle32 idle32;
722 	struct ppp_idle64 idle64;
723 	struct npioctl npi;
724 	int unit, cflags;
725 	struct slcompress *vj;
726 	void __user *argp = (void __user *)arg;
727 	int __user *p = argp;
728 
729 	mutex_lock(&ppp_mutex);
730 
731 	pf = file->private_data;
732 	if (!pf) {
733 		err = ppp_unattached_ioctl(current->nsproxy->net_ns,
734 					   pf, file, cmd, arg);
735 		goto out;
736 	}
737 
738 	if (cmd == PPPIOCDETACH) {
739 		/*
740 		 * PPPIOCDETACH is no longer supported as it was heavily broken,
741 		 * and is only known to have been used by pppd older than
742 		 * ppp-2.4.2 (released November 2003).
743 		 */
744 		pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
745 			     current->comm, current->pid);
746 		err = -EINVAL;
747 		goto out;
748 	}
749 
750 	if (pf->kind == CHANNEL) {
751 		struct channel *pch, *pchb;
752 		struct ppp_channel *chan;
753 		struct ppp_net *pn;
754 
755 		pch = PF_TO_CHANNEL(pf);
756 
757 		switch (cmd) {
758 		case PPPIOCCONNECT:
759 			if (get_user(unit, p))
760 				break;
761 			err = ppp_connect_channel(pch, unit);
762 			break;
763 
764 		case PPPIOCDISCONN:
765 			err = ppp_disconnect_channel(pch);
766 			break;
767 
768 		case PPPIOCBRIDGECHAN:
769 			if (get_user(unit, p))
770 				break;
771 			err = -ENXIO;
772 			pn = ppp_pernet(current->nsproxy->net_ns);
773 			spin_lock_bh(&pn->all_channels_lock);
774 			pchb = ppp_find_channel(pn, unit);
775 			/* Hold a reference to prevent pchb being freed while
776 			 * we establish the bridge.
777 			 */
778 			if (pchb)
779 				refcount_inc(&pchb->file.refcnt);
780 			spin_unlock_bh(&pn->all_channels_lock);
781 			if (!pchb)
782 				break;
783 			err = ppp_bridge_channels(pch, pchb);
784 			/* Drop earlier refcount now bridge establishment is complete */
785 			if (refcount_dec_and_test(&pchb->file.refcnt))
786 				ppp_destroy_channel(pchb);
787 			break;
788 
789 		case PPPIOCUNBRIDGECHAN:
790 			err = ppp_unbridge_channels(pch);
791 			break;
792 
793 		default:
794 			down_read(&pch->chan_sem);
795 			chan = pch->chan;
796 			err = -ENOTTY;
797 			if (chan && chan->ops->ioctl)
798 				err = chan->ops->ioctl(chan, cmd, arg);
799 			up_read(&pch->chan_sem);
800 		}
801 		goto out;
802 	}
803 
804 	if (pf->kind != INTERFACE) {
805 		/* can't happen */
806 		pr_err("PPP: not interface or channel??\n");
807 		err = -EINVAL;
808 		goto out;
809 	}
810 
811 	ppp = PF_TO_PPP(pf);
812 	switch (cmd) {
813 	case PPPIOCSMRU:
814 		if (get_user(val, p))
815 			break;
816 		ppp->mru = val;
817 		err = 0;
818 		break;
819 
820 	case PPPIOCSFLAGS:
821 		if (get_user(val, p))
822 			break;
823 		ppp_lock(ppp);
824 		cflags = ppp->flags & ~val;
825 #ifdef CONFIG_PPP_MULTILINK
826 		if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
827 			ppp->nextseq = 0;
828 #endif
829 		ppp->flags = val & SC_FLAG_BITS;
830 		ppp_unlock(ppp);
831 		if (cflags & SC_CCP_OPEN)
832 			ppp_ccp_closed(ppp);
833 		err = 0;
834 		break;
835 
836 	case PPPIOCGFLAGS:
837 		val = ppp->flags | ppp->xstate | ppp->rstate;
838 		if (put_user(val, p))
839 			break;
840 		err = 0;
841 		break;
842 
843 	case PPPIOCSCOMPRESS:
844 	{
845 		struct ppp_option_data data;
846 		if (copy_from_user(&data, argp, sizeof(data)))
847 			err = -EFAULT;
848 		else
849 			err = ppp_set_compress(ppp, &data);
850 		break;
851 	}
852 	case PPPIOCGUNIT:
853 		if (put_user(ppp->file.index, p))
854 			break;
855 		err = 0;
856 		break;
857 
858 	case PPPIOCSDEBUG:
859 		if (get_user(val, p))
860 			break;
861 		ppp->debug = val;
862 		err = 0;
863 		break;
864 
865 	case PPPIOCGDEBUG:
866 		if (put_user(ppp->debug, p))
867 			break;
868 		err = 0;
869 		break;
870 
871 	case PPPIOCGIDLE32:
872                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
873                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
874                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
875 			break;
876 		err = 0;
877 		break;
878 
879 	case PPPIOCGIDLE64:
880 		idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
881 		idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
882 		if (copy_to_user(argp, &idle64, sizeof(idle64)))
883 			break;
884 		err = 0;
885 		break;
886 
887 	case PPPIOCSMAXCID:
888 		if (get_user(val, p))
889 			break;
890 		val2 = 15;
891 		if ((val >> 16) != 0) {
892 			val2 = val >> 16;
893 			val &= 0xffff;
894 		}
895 		vj = slhc_init(val2+1, val+1);
896 		if (IS_ERR(vj)) {
897 			err = PTR_ERR(vj);
898 			break;
899 		}
900 		ppp_lock(ppp);
901 		if (ppp->vj)
902 			slhc_free(ppp->vj);
903 		ppp->vj = vj;
904 		ppp_unlock(ppp);
905 		err = 0;
906 		break;
907 
908 	case PPPIOCGNPMODE:
909 	case PPPIOCSNPMODE:
910 		if (copy_from_user(&npi, argp, sizeof(npi)))
911 			break;
912 		err = proto_to_npindex(npi.protocol);
913 		if (err < 0)
914 			break;
915 		i = err;
916 		if (cmd == PPPIOCGNPMODE) {
917 			err = -EFAULT;
918 			npi.mode = ppp->npmode[i];
919 			if (copy_to_user(argp, &npi, sizeof(npi)))
920 				break;
921 		} else {
922 			ppp->npmode[i] = npi.mode;
923 			/* we may be able to transmit more packets now (??) */
924 			netif_wake_queue(ppp->dev);
925 		}
926 		err = 0;
927 		break;
928 
929 #ifdef CONFIG_PPP_FILTER
930 	case PPPIOCSPASS:
931 	case PPPIOCSACTIVE:
932 	{
933 		struct bpf_prog *filter = ppp_get_filter(argp);
934 		struct bpf_prog **which;
935 
936 		if (IS_ERR(filter)) {
937 			err = PTR_ERR(filter);
938 			break;
939 		}
940 		if (cmd == PPPIOCSPASS)
941 			which = &ppp->pass_filter;
942 		else
943 			which = &ppp->active_filter;
944 		ppp_lock(ppp);
945 		if (*which)
946 			bpf_prog_destroy(*which);
947 		*which = filter;
948 		ppp_unlock(ppp);
949 		err = 0;
950 		break;
951 	}
952 #endif /* CONFIG_PPP_FILTER */
953 
954 #ifdef CONFIG_PPP_MULTILINK
955 	case PPPIOCSMRRU:
956 		if (get_user(val, p))
957 			break;
958 		ppp_recv_lock(ppp);
959 		ppp->mrru = val;
960 		ppp_recv_unlock(ppp);
961 		err = 0;
962 		break;
963 #endif /* CONFIG_PPP_MULTILINK */
964 
965 	default:
966 		err = -ENOTTY;
967 	}
968 
969 out:
970 	mutex_unlock(&ppp_mutex);
971 
972 	return err;
973 }
974 
975 #ifdef CONFIG_COMPAT
976 struct ppp_option_data32 {
977 	compat_uptr_t		ptr;
978 	u32			length;
979 	compat_int_t		transmit;
980 };
981 #define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)
982 
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)983 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
984 {
985 	struct ppp_file *pf;
986 	int err = -ENOIOCTLCMD;
987 	void __user *argp = (void __user *)arg;
988 
989 	mutex_lock(&ppp_mutex);
990 
991 	pf = file->private_data;
992 	if (pf && pf->kind == INTERFACE) {
993 		struct ppp *ppp = PF_TO_PPP(pf);
994 		switch (cmd) {
995 #ifdef CONFIG_PPP_FILTER
996 		case PPPIOCSPASS32:
997 		case PPPIOCSACTIVE32:
998 		{
999 			struct bpf_prog *filter = compat_ppp_get_filter(argp);
1000 			struct bpf_prog **which;
1001 
1002 			if (IS_ERR(filter)) {
1003 				err = PTR_ERR(filter);
1004 				break;
1005 			}
1006 			if (cmd == PPPIOCSPASS32)
1007 				which = &ppp->pass_filter;
1008 			else
1009 				which = &ppp->active_filter;
1010 			ppp_lock(ppp);
1011 			if (*which)
1012 				bpf_prog_destroy(*which);
1013 			*which = filter;
1014 			ppp_unlock(ppp);
1015 			err = 0;
1016 			break;
1017 		}
1018 #endif /* CONFIG_PPP_FILTER */
1019 		case PPPIOCSCOMPRESS32:
1020 		{
1021 			struct ppp_option_data32 data32;
1022 			if (copy_from_user(&data32, argp, sizeof(data32))) {
1023 				err = -EFAULT;
1024 			} else {
1025 				struct ppp_option_data data = {
1026 					.ptr = compat_ptr(data32.ptr),
1027 					.length = data32.length,
1028 					.transmit = data32.transmit
1029 				};
1030 				err = ppp_set_compress(ppp, &data);
1031 			}
1032 			break;
1033 		}
1034 		}
1035 	}
1036 	mutex_unlock(&ppp_mutex);
1037 
1038 	/* all other commands have compatible arguments */
1039 	if (err == -ENOIOCTLCMD)
1040 		err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1041 
1042 	return err;
1043 }
1044 #endif
1045 
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)1046 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1047 			struct file *file, unsigned int cmd, unsigned long arg)
1048 {
1049 	int unit, err = -EFAULT;
1050 	struct ppp *ppp;
1051 	struct channel *chan;
1052 	struct ppp_net *pn;
1053 	int __user *p = (int __user *)arg;
1054 
1055 	switch (cmd) {
1056 	case PPPIOCNEWUNIT:
1057 		/* Create a new ppp unit */
1058 		if (get_user(unit, p))
1059 			break;
1060 		err = ppp_create_interface(net, file, &unit);
1061 		if (err < 0)
1062 			break;
1063 
1064 		err = -EFAULT;
1065 		if (put_user(unit, p))
1066 			break;
1067 		err = 0;
1068 		break;
1069 
1070 	case PPPIOCATTACH:
1071 		/* Attach to an existing ppp unit */
1072 		if (get_user(unit, p))
1073 			break;
1074 		err = -ENXIO;
1075 		pn = ppp_pernet(net);
1076 		mutex_lock(&pn->all_ppp_mutex);
1077 		ppp = ppp_find_unit(pn, unit);
1078 		if (ppp) {
1079 			refcount_inc(&ppp->file.refcnt);
1080 			file->private_data = &ppp->file;
1081 			err = 0;
1082 		}
1083 		mutex_unlock(&pn->all_ppp_mutex);
1084 		break;
1085 
1086 	case PPPIOCATTCHAN:
1087 		if (get_user(unit, p))
1088 			break;
1089 		err = -ENXIO;
1090 		pn = ppp_pernet(net);
1091 		spin_lock_bh(&pn->all_channels_lock);
1092 		chan = ppp_find_channel(pn, unit);
1093 		if (chan) {
1094 			refcount_inc(&chan->file.refcnt);
1095 			file->private_data = &chan->file;
1096 			err = 0;
1097 		}
1098 		spin_unlock_bh(&pn->all_channels_lock);
1099 		break;
1100 
1101 	default:
1102 		err = -ENOTTY;
1103 	}
1104 
1105 	return err;
1106 }
1107 
1108 static const struct file_operations ppp_device_fops = {
1109 	.owner		= THIS_MODULE,
1110 	.read		= ppp_read,
1111 	.write		= ppp_write,
1112 	.poll		= ppp_poll,
1113 	.unlocked_ioctl	= ppp_ioctl,
1114 #ifdef CONFIG_COMPAT
1115 	.compat_ioctl	= ppp_compat_ioctl,
1116 #endif
1117 	.open		= ppp_open,
1118 	.release	= ppp_release,
1119 	.llseek		= noop_llseek,
1120 };
1121 
ppp_init_net(struct net * net)1122 static __net_init int ppp_init_net(struct net *net)
1123 {
1124 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1125 
1126 	idr_init(&pn->units_idr);
1127 	mutex_init(&pn->all_ppp_mutex);
1128 
1129 	INIT_LIST_HEAD(&pn->all_channels);
1130 	INIT_LIST_HEAD(&pn->new_channels);
1131 
1132 	spin_lock_init(&pn->all_channels_lock);
1133 
1134 	return 0;
1135 }
1136 
ppp_exit_net(struct net * net)1137 static __net_exit void ppp_exit_net(struct net *net)
1138 {
1139 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1140 	struct net_device *dev;
1141 	struct net_device *aux;
1142 	struct ppp *ppp;
1143 	LIST_HEAD(list);
1144 	int id;
1145 
1146 	rtnl_lock();
1147 	for_each_netdev_safe(net, dev, aux) {
1148 		if (dev->netdev_ops == &ppp_netdev_ops)
1149 			unregister_netdevice_queue(dev, &list);
1150 	}
1151 
1152 	idr_for_each_entry(&pn->units_idr, ppp, id)
1153 		/* Skip devices already unregistered by previous loop */
1154 		if (!net_eq(dev_net(ppp->dev), net))
1155 			unregister_netdevice_queue(ppp->dev, &list);
1156 
1157 	unregister_netdevice_many(&list);
1158 	rtnl_unlock();
1159 
1160 	mutex_destroy(&pn->all_ppp_mutex);
1161 	idr_destroy(&pn->units_idr);
1162 	WARN_ON_ONCE(!list_empty(&pn->all_channels));
1163 	WARN_ON_ONCE(!list_empty(&pn->new_channels));
1164 }
1165 
1166 static struct pernet_operations ppp_net_ops = {
1167 	.init = ppp_init_net,
1168 	.exit = ppp_exit_net,
1169 	.id   = &ppp_net_id,
1170 	.size = sizeof(struct ppp_net),
1171 };
1172 
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1173 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1174 {
1175 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1176 	int ret;
1177 
1178 	mutex_lock(&pn->all_ppp_mutex);
1179 
1180 	if (unit < 0) {
1181 		ret = unit_get(&pn->units_idr, ppp, 0);
1182 		if (ret < 0)
1183 			goto err;
1184 		if (!ifname_is_set) {
1185 			while (1) {
1186 				snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1187 				if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1188 					break;
1189 				unit_put(&pn->units_idr, ret);
1190 				ret = unit_get(&pn->units_idr, ppp, ret + 1);
1191 				if (ret < 0)
1192 					goto err;
1193 			}
1194 		}
1195 	} else {
1196 		/* Caller asked for a specific unit number. Fail with -EEXIST
1197 		 * if unavailable. For backward compatibility, return -EEXIST
1198 		 * too if idr allocation fails; this makes pppd retry without
1199 		 * requesting a specific unit number.
1200 		 */
1201 		if (unit_find(&pn->units_idr, unit)) {
1202 			ret = -EEXIST;
1203 			goto err;
1204 		}
1205 		ret = unit_set(&pn->units_idr, ppp, unit);
1206 		if (ret < 0) {
1207 			/* Rewrite error for backward compatibility */
1208 			ret = -EEXIST;
1209 			goto err;
1210 		}
1211 	}
1212 	ppp->file.index = ret;
1213 
1214 	if (!ifname_is_set)
1215 		snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1216 
1217 	mutex_unlock(&pn->all_ppp_mutex);
1218 
1219 	ret = register_netdevice(ppp->dev);
1220 	if (ret < 0)
1221 		goto err_unit;
1222 
1223 	atomic_inc(&ppp_unit_count);
1224 
1225 	return 0;
1226 
1227 err_unit:
1228 	mutex_lock(&pn->all_ppp_mutex);
1229 	unit_put(&pn->units_idr, ppp->file.index);
1230 err:
1231 	mutex_unlock(&pn->all_ppp_mutex);
1232 
1233 	return ret;
1234 }
1235 
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1236 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1237 			     const struct ppp_config *conf)
1238 {
1239 	struct ppp *ppp = netdev_priv(dev);
1240 	int indx;
1241 	int err;
1242 	int cpu;
1243 
1244 	ppp->dev = dev;
1245 	ppp->ppp_net = src_net;
1246 	ppp->mru = PPP_MRU;
1247 	ppp->owner = conf->file;
1248 
1249 	init_ppp_file(&ppp->file, INTERFACE);
1250 	ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1251 
1252 	for (indx = 0; indx < NUM_NP; ++indx)
1253 		ppp->npmode[indx] = NPMODE_PASS;
1254 	INIT_LIST_HEAD(&ppp->channels);
1255 	spin_lock_init(&ppp->rlock);
1256 	spin_lock_init(&ppp->wlock);
1257 
1258 	ppp->xmit_recursion = alloc_percpu(int);
1259 	if (!ppp->xmit_recursion) {
1260 		err = -ENOMEM;
1261 		goto err1;
1262 	}
1263 	for_each_possible_cpu(cpu)
1264 		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1265 
1266 #ifdef CONFIG_PPP_MULTILINK
1267 	ppp->minseq = -1;
1268 	skb_queue_head_init(&ppp->mrq);
1269 #endif /* CONFIG_PPP_MULTILINK */
1270 #ifdef CONFIG_PPP_FILTER
1271 	ppp->pass_filter = NULL;
1272 	ppp->active_filter = NULL;
1273 #endif /* CONFIG_PPP_FILTER */
1274 
1275 	err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1276 	if (err < 0)
1277 		goto err2;
1278 
1279 	conf->file->private_data = &ppp->file;
1280 
1281 	return 0;
1282 err2:
1283 	free_percpu(ppp->xmit_recursion);
1284 err1:
1285 	return err;
1286 }
1287 
1288 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1289 	[IFLA_PPP_DEV_FD]	= { .type = NLA_S32 },
1290 };
1291 
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1292 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1293 			   struct netlink_ext_ack *extack)
1294 {
1295 	if (!data)
1296 		return -EINVAL;
1297 
1298 	if (!data[IFLA_PPP_DEV_FD])
1299 		return -EINVAL;
1300 	if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1301 		return -EBADF;
1302 
1303 	return 0;
1304 }
1305 
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1306 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1307 			  struct nlattr *tb[], struct nlattr *data[],
1308 			  struct netlink_ext_ack *extack)
1309 {
1310 	struct ppp_config conf = {
1311 		.unit = -1,
1312 		.ifname_is_set = true,
1313 	};
1314 	struct file *file;
1315 	int err;
1316 
1317 	file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1318 	if (!file)
1319 		return -EBADF;
1320 
1321 	/* rtnl_lock is already held here, but ppp_create_interface() locks
1322 	 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1323 	 * possible deadlock due to lock order inversion, at the cost of
1324 	 * pushing the problem back to userspace.
1325 	 */
1326 	if (!mutex_trylock(&ppp_mutex)) {
1327 		err = -EBUSY;
1328 		goto out;
1329 	}
1330 
1331 	if (file->f_op != &ppp_device_fops || file->private_data) {
1332 		err = -EBADF;
1333 		goto out_unlock;
1334 	}
1335 
1336 	conf.file = file;
1337 
1338 	/* Don't use device name generated by the rtnetlink layer when ifname
1339 	 * isn't specified. Let ppp_dev_configure() set the device name using
1340 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1341 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1342 	 */
1343 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1344 		conf.ifname_is_set = false;
1345 
1346 	err = ppp_dev_configure(src_net, dev, &conf);
1347 
1348 out_unlock:
1349 	mutex_unlock(&ppp_mutex);
1350 out:
1351 	fput(file);
1352 
1353 	return err;
1354 }
1355 
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1356 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1357 {
1358 	unregister_netdevice_queue(dev, head);
1359 }
1360 
ppp_nl_get_size(const struct net_device * dev)1361 static size_t ppp_nl_get_size(const struct net_device *dev)
1362 {
1363 	return 0;
1364 }
1365 
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1366 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1367 {
1368 	return 0;
1369 }
1370 
ppp_nl_get_link_net(const struct net_device * dev)1371 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1372 {
1373 	struct ppp *ppp = netdev_priv(dev);
1374 
1375 	return READ_ONCE(ppp->ppp_net);
1376 }
1377 
1378 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1379 	.kind		= "ppp",
1380 	.maxtype	= IFLA_PPP_MAX,
1381 	.policy		= ppp_nl_policy,
1382 	.priv_size	= sizeof(struct ppp),
1383 	.setup		= ppp_setup,
1384 	.validate	= ppp_nl_validate,
1385 	.newlink	= ppp_nl_newlink,
1386 	.dellink	= ppp_nl_dellink,
1387 	.get_size	= ppp_nl_get_size,
1388 	.fill_info	= ppp_nl_fill_info,
1389 	.get_link_net	= ppp_nl_get_link_net,
1390 };
1391 
1392 #define PPP_MAJOR	108
1393 
1394 /* Called at boot time if ppp is compiled into the kernel,
1395    or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1396 static int __init ppp_init(void)
1397 {
1398 	int err;
1399 
1400 	pr_info("PPP generic driver version " PPP_VERSION "\n");
1401 
1402 	err = register_pernet_device(&ppp_net_ops);
1403 	if (err) {
1404 		pr_err("failed to register PPP pernet device (%d)\n", err);
1405 		goto out;
1406 	}
1407 
1408 	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1409 	if (err) {
1410 		pr_err("failed to register PPP device (%d)\n", err);
1411 		goto out_net;
1412 	}
1413 
1414 	err = class_register(&ppp_class);
1415 	if (err)
1416 		goto out_chrdev;
1417 
1418 	err = rtnl_link_register(&ppp_link_ops);
1419 	if (err) {
1420 		pr_err("failed to register rtnetlink PPP handler\n");
1421 		goto out_class;
1422 	}
1423 
1424 	/* not a big deal if we fail here :-) */
1425 	device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1426 
1427 	return 0;
1428 
1429 out_class:
1430 	class_unregister(&ppp_class);
1431 out_chrdev:
1432 	unregister_chrdev(PPP_MAJOR, "ppp");
1433 out_net:
1434 	unregister_pernet_device(&ppp_net_ops);
1435 out:
1436 	return err;
1437 }
1438 
1439 /*
1440  * Network interface unit routines.
1441  */
1442 static netdev_tx_t
ppp_start_xmit(struct sk_buff * skb,struct net_device * dev)1443 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1444 {
1445 	struct ppp *ppp = netdev_priv(dev);
1446 	int npi, proto;
1447 	unsigned char *pp;
1448 
1449 	npi = ethertype_to_npindex(ntohs(skb->protocol));
1450 	if (npi < 0)
1451 		goto outf;
1452 
1453 	/* Drop, accept or reject the packet */
1454 	switch (ppp->npmode[npi]) {
1455 	case NPMODE_PASS:
1456 		break;
1457 	case NPMODE_QUEUE:
1458 		/* it would be nice to have a way to tell the network
1459 		   system to queue this one up for later. */
1460 		goto outf;
1461 	case NPMODE_DROP:
1462 	case NPMODE_ERROR:
1463 		goto outf;
1464 	}
1465 
1466 	/* Put the 2-byte PPP protocol number on the front,
1467 	   making sure there is room for the address and control fields. */
1468 	if (skb_cow_head(skb, PPP_HDRLEN))
1469 		goto outf;
1470 
1471 	pp = skb_push(skb, 2);
1472 	proto = npindex_to_proto[npi];
1473 	put_unaligned_be16(proto, pp);
1474 
1475 	skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1476 	ppp_xmit_process(ppp, skb);
1477 
1478 	return NETDEV_TX_OK;
1479 
1480  outf:
1481 	kfree_skb(skb);
1482 	++dev->stats.tx_dropped;
1483 	return NETDEV_TX_OK;
1484 }
1485 
1486 static int
ppp_net_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * addr,int cmd)1487 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1488 		       void __user *addr, int cmd)
1489 {
1490 	struct ppp *ppp = netdev_priv(dev);
1491 	int err = -EFAULT;
1492 	struct ppp_stats stats;
1493 	struct ppp_comp_stats cstats;
1494 	char *vers;
1495 
1496 	switch (cmd) {
1497 	case SIOCGPPPSTATS:
1498 		ppp_get_stats(ppp, &stats);
1499 		if (copy_to_user(addr, &stats, sizeof(stats)))
1500 			break;
1501 		err = 0;
1502 		break;
1503 
1504 	case SIOCGPPPCSTATS:
1505 		memset(&cstats, 0, sizeof(cstats));
1506 		if (ppp->xc_state)
1507 			ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1508 		if (ppp->rc_state)
1509 			ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1510 		if (copy_to_user(addr, &cstats, sizeof(cstats)))
1511 			break;
1512 		err = 0;
1513 		break;
1514 
1515 	case SIOCGPPPVER:
1516 		vers = PPP_VERSION;
1517 		if (copy_to_user(addr, vers, strlen(vers) + 1))
1518 			break;
1519 		err = 0;
1520 		break;
1521 
1522 	default:
1523 		err = -EINVAL;
1524 	}
1525 
1526 	return err;
1527 }
1528 
1529 static void
ppp_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats64)1530 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1531 {
1532 	struct ppp *ppp = netdev_priv(dev);
1533 
1534 	ppp_recv_lock(ppp);
1535 	stats64->rx_packets = ppp->stats64.rx_packets;
1536 	stats64->rx_bytes   = ppp->stats64.rx_bytes;
1537 	ppp_recv_unlock(ppp);
1538 
1539 	ppp_xmit_lock(ppp);
1540 	stats64->tx_packets = ppp->stats64.tx_packets;
1541 	stats64->tx_bytes   = ppp->stats64.tx_bytes;
1542 	ppp_xmit_unlock(ppp);
1543 
1544 	stats64->rx_errors        = dev->stats.rx_errors;
1545 	stats64->tx_errors        = dev->stats.tx_errors;
1546 	stats64->rx_dropped       = dev->stats.rx_dropped;
1547 	stats64->tx_dropped       = dev->stats.tx_dropped;
1548 	stats64->rx_length_errors = dev->stats.rx_length_errors;
1549 }
1550 
ppp_dev_init(struct net_device * dev)1551 static int ppp_dev_init(struct net_device *dev)
1552 {
1553 	struct ppp *ppp;
1554 
1555 	netdev_lockdep_set_classes(dev);
1556 
1557 	ppp = netdev_priv(dev);
1558 	/* Let the netdevice take a reference on the ppp file. This ensures
1559 	 * that ppp_destroy_interface() won't run before the device gets
1560 	 * unregistered.
1561 	 */
1562 	refcount_inc(&ppp->file.refcnt);
1563 
1564 	return 0;
1565 }
1566 
ppp_dev_uninit(struct net_device * dev)1567 static void ppp_dev_uninit(struct net_device *dev)
1568 {
1569 	struct ppp *ppp = netdev_priv(dev);
1570 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1571 
1572 	ppp_lock(ppp);
1573 	ppp->closing = 1;
1574 	ppp_unlock(ppp);
1575 
1576 	mutex_lock(&pn->all_ppp_mutex);
1577 	unit_put(&pn->units_idr, ppp->file.index);
1578 	mutex_unlock(&pn->all_ppp_mutex);
1579 
1580 	ppp->owner = NULL;
1581 
1582 	ppp->file.dead = 1;
1583 	wake_up_interruptible(&ppp->file.rwait);
1584 }
1585 
ppp_dev_priv_destructor(struct net_device * dev)1586 static void ppp_dev_priv_destructor(struct net_device *dev)
1587 {
1588 	struct ppp *ppp;
1589 
1590 	ppp = netdev_priv(dev);
1591 	if (refcount_dec_and_test(&ppp->file.refcnt))
1592 		ppp_destroy_interface(ppp);
1593 }
1594 
ppp_fill_forward_path(struct net_device_path_ctx * ctx,struct net_device_path * path)1595 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1596 				 struct net_device_path *path)
1597 {
1598 	struct ppp *ppp = netdev_priv(ctx->dev);
1599 	struct ppp_channel *chan;
1600 	struct channel *pch;
1601 
1602 	if (ppp->flags & SC_MULTILINK)
1603 		return -EOPNOTSUPP;
1604 
1605 	if (list_empty(&ppp->channels))
1606 		return -ENODEV;
1607 
1608 	pch = list_first_entry(&ppp->channels, struct channel, clist);
1609 	chan = pch->chan;
1610 	if (!chan->ops->fill_forward_path)
1611 		return -EOPNOTSUPP;
1612 
1613 	return chan->ops->fill_forward_path(ctx, path, chan);
1614 }
1615 
1616 static const struct net_device_ops ppp_netdev_ops = {
1617 	.ndo_init	 = ppp_dev_init,
1618 	.ndo_uninit      = ppp_dev_uninit,
1619 	.ndo_start_xmit  = ppp_start_xmit,
1620 	.ndo_siocdevprivate = ppp_net_siocdevprivate,
1621 	.ndo_get_stats64 = ppp_get_stats64,
1622 	.ndo_fill_forward_path = ppp_fill_forward_path,
1623 };
1624 
1625 static const struct device_type ppp_type = {
1626 	.name = "ppp",
1627 };
1628 
ppp_setup(struct net_device * dev)1629 static void ppp_setup(struct net_device *dev)
1630 {
1631 	dev->netdev_ops = &ppp_netdev_ops;
1632 	SET_NETDEV_DEVTYPE(dev, &ppp_type);
1633 
1634 	dev->lltx = true;
1635 
1636 	dev->hard_header_len = PPP_HDRLEN;
1637 	dev->mtu = PPP_MRU;
1638 	dev->addr_len = 0;
1639 	dev->tx_queue_len = 3;
1640 	dev->type = ARPHRD_PPP;
1641 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1642 	dev->priv_destructor = ppp_dev_priv_destructor;
1643 	netif_keep_dst(dev);
1644 }
1645 
1646 /*
1647  * Transmit-side routines.
1648  */
1649 
1650 /* 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)1651 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1652 {
1653 	ppp_xmit_lock(ppp);
1654 	if (!ppp->closing) {
1655 		ppp_push(ppp);
1656 
1657 		if (skb)
1658 			skb_queue_tail(&ppp->file.xq, skb);
1659 		while (!ppp->xmit_pending &&
1660 		       (skb = skb_dequeue(&ppp->file.xq)))
1661 			ppp_send_frame(ppp, skb);
1662 		/* If there's no work left to do, tell the core net
1663 		   code that we can accept some more. */
1664 		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1665 			netif_wake_queue(ppp->dev);
1666 		else
1667 			netif_stop_queue(ppp->dev);
1668 	} else {
1669 		kfree_skb(skb);
1670 	}
1671 	ppp_xmit_unlock(ppp);
1672 }
1673 
ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1674 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1675 {
1676 	local_bh_disable();
1677 
1678 	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1679 		goto err;
1680 
1681 	(*this_cpu_ptr(ppp->xmit_recursion))++;
1682 	__ppp_xmit_process(ppp, skb);
1683 	(*this_cpu_ptr(ppp->xmit_recursion))--;
1684 
1685 	local_bh_enable();
1686 
1687 	return;
1688 
1689 err:
1690 	local_bh_enable();
1691 
1692 	kfree_skb(skb);
1693 
1694 	if (net_ratelimit())
1695 		netdev_err(ppp->dev, "recursion detected\n");
1696 }
1697 
1698 static inline struct sk_buff *
pad_compress_skb(struct ppp * ppp,struct sk_buff * skb)1699 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1700 {
1701 	struct sk_buff *new_skb;
1702 	int len;
1703 	int new_skb_size = ppp->dev->mtu +
1704 		ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1705 	int compressor_skb_size = ppp->dev->mtu +
1706 		ppp->xcomp->comp_extra + PPP_HDRLEN;
1707 	new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1708 	if (!new_skb) {
1709 		if (net_ratelimit())
1710 			netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1711 		return NULL;
1712 	}
1713 	if (ppp->dev->hard_header_len > PPP_HDRLEN)
1714 		skb_reserve(new_skb,
1715 			    ppp->dev->hard_header_len - PPP_HDRLEN);
1716 
1717 	/* compressor still expects A/C bytes in hdr */
1718 	len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1719 				   new_skb->data, skb->len + 2,
1720 				   compressor_skb_size);
1721 	if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1722 		consume_skb(skb);
1723 		skb = new_skb;
1724 		skb_put(skb, len);
1725 		skb_pull(skb, 2);	/* pull off A/C bytes */
1726 	} else if (len == 0) {
1727 		/* didn't compress, or CCP not up yet */
1728 		consume_skb(new_skb);
1729 		new_skb = skb;
1730 	} else {
1731 		/*
1732 		 * (len < 0)
1733 		 * MPPE requires that we do not send unencrypted
1734 		 * frames.  The compressor will return -1 if we
1735 		 * should drop the frame.  We cannot simply test
1736 		 * the compress_proto because MPPE and MPPC share
1737 		 * the same number.
1738 		 */
1739 		if (net_ratelimit())
1740 			netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1741 		kfree_skb(skb);
1742 		consume_skb(new_skb);
1743 		new_skb = NULL;
1744 	}
1745 	return new_skb;
1746 }
1747 
1748 /*
1749  * Compress and send a frame.
1750  * The caller should have locked the xmit path,
1751  * and xmit_pending should be 0.
1752  */
1753 static void
ppp_send_frame(struct ppp * ppp,struct sk_buff * skb)1754 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1755 {
1756 	int proto = PPP_PROTO(skb);
1757 	struct sk_buff *new_skb;
1758 	int len;
1759 	unsigned char *cp;
1760 
1761 	skb->dev = ppp->dev;
1762 
1763 	if (proto < 0x8000) {
1764 #ifdef CONFIG_PPP_FILTER
1765 		/* check if we should pass this packet */
1766 		/* the filter instructions are constructed assuming
1767 		   a four-byte PPP header on each packet */
1768 		*(u8 *)skb_push(skb, 2) = 1;
1769 		if (ppp->pass_filter &&
1770 		    bpf_prog_run(ppp->pass_filter, skb) == 0) {
1771 			if (ppp->debug & 1)
1772 				netdev_printk(KERN_DEBUG, ppp->dev,
1773 					      "PPP: outbound frame "
1774 					      "not passed\n");
1775 			kfree_skb(skb);
1776 			return;
1777 		}
1778 		/* if this packet passes the active filter, record the time */
1779 		if (!(ppp->active_filter &&
1780 		      bpf_prog_run(ppp->active_filter, skb) == 0))
1781 			ppp->last_xmit = jiffies;
1782 		skb_pull(skb, 2);
1783 #else
1784 		/* for data packets, record the time */
1785 		ppp->last_xmit = jiffies;
1786 #endif /* CONFIG_PPP_FILTER */
1787 	}
1788 
1789 	++ppp->stats64.tx_packets;
1790 	ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1791 
1792 	switch (proto) {
1793 	case PPP_IP:
1794 		if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1795 			break;
1796 		/* try to do VJ TCP header compression */
1797 		new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1798 				    GFP_ATOMIC);
1799 		if (!new_skb) {
1800 			netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1801 			goto drop;
1802 		}
1803 		skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1804 		cp = skb->data + 2;
1805 		len = slhc_compress(ppp->vj, cp, skb->len - 2,
1806 				    new_skb->data + 2, &cp,
1807 				    !(ppp->flags & SC_NO_TCP_CCID));
1808 		if (cp == skb->data + 2) {
1809 			/* didn't compress */
1810 			consume_skb(new_skb);
1811 		} else {
1812 			if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1813 				proto = PPP_VJC_COMP;
1814 				cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1815 			} else {
1816 				proto = PPP_VJC_UNCOMP;
1817 				cp[0] = skb->data[2];
1818 			}
1819 			consume_skb(skb);
1820 			skb = new_skb;
1821 			cp = skb_put(skb, len + 2);
1822 			cp[0] = 0;
1823 			cp[1] = proto;
1824 		}
1825 		break;
1826 
1827 	case PPP_CCP:
1828 		/* peek at outbound CCP frames */
1829 		ppp_ccp_peek(ppp, skb, 0);
1830 		break;
1831 	}
1832 
1833 	/* try to do packet compression */
1834 	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1835 	    proto != PPP_LCP && proto != PPP_CCP) {
1836 		if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1837 			if (net_ratelimit())
1838 				netdev_err(ppp->dev,
1839 					   "ppp: compression required but "
1840 					   "down - pkt dropped.\n");
1841 			goto drop;
1842 		}
1843 		skb = pad_compress_skb(ppp, skb);
1844 		if (!skb)
1845 			goto drop;
1846 	}
1847 
1848 	/*
1849 	 * If we are waiting for traffic (demand dialling),
1850 	 * queue it up for pppd to receive.
1851 	 */
1852 	if (ppp->flags & SC_LOOP_TRAFFIC) {
1853 		if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1854 			goto drop;
1855 		skb_queue_tail(&ppp->file.rq, skb);
1856 		wake_up_interruptible(&ppp->file.rwait);
1857 		return;
1858 	}
1859 
1860 	ppp->xmit_pending = skb;
1861 	ppp_push(ppp);
1862 	return;
1863 
1864  drop:
1865 	kfree_skb(skb);
1866 	++ppp->dev->stats.tx_errors;
1867 }
1868 
1869 /*
1870  * Try to send the frame in xmit_pending.
1871  * The caller should have the xmit path locked.
1872  */
1873 static void
ppp_push(struct ppp * ppp)1874 ppp_push(struct ppp *ppp)
1875 {
1876 	struct list_head *list;
1877 	struct channel *pch;
1878 	struct sk_buff *skb = ppp->xmit_pending;
1879 
1880 	if (!skb)
1881 		return;
1882 
1883 	list = &ppp->channels;
1884 	if (list_empty(list)) {
1885 		/* nowhere to send the packet, just drop it */
1886 		ppp->xmit_pending = NULL;
1887 		kfree_skb(skb);
1888 		return;
1889 	}
1890 
1891 	if ((ppp->flags & SC_MULTILINK) == 0) {
1892 		/* not doing multilink: send it down the first channel */
1893 		list = list->next;
1894 		pch = list_entry(list, struct channel, clist);
1895 
1896 		spin_lock(&pch->downl);
1897 		if (pch->chan) {
1898 			if (pch->chan->ops->start_xmit(pch->chan, skb))
1899 				ppp->xmit_pending = NULL;
1900 		} else {
1901 			/* channel got unregistered */
1902 			kfree_skb(skb);
1903 			ppp->xmit_pending = NULL;
1904 		}
1905 		spin_unlock(&pch->downl);
1906 		return;
1907 	}
1908 
1909 #ifdef CONFIG_PPP_MULTILINK
1910 	/* Multilink: fragment the packet over as many links
1911 	   as can take the packet at the moment. */
1912 	if (!ppp_mp_explode(ppp, skb))
1913 		return;
1914 #endif /* CONFIG_PPP_MULTILINK */
1915 
1916 	ppp->xmit_pending = NULL;
1917 	kfree_skb(skb);
1918 }
1919 
1920 #ifdef CONFIG_PPP_MULTILINK
1921 static bool mp_protocol_compress __read_mostly = true;
1922 module_param(mp_protocol_compress, bool, 0644);
1923 MODULE_PARM_DESC(mp_protocol_compress,
1924 		 "compress protocol id in multilink fragments");
1925 
1926 /*
1927  * Divide a packet to be transmitted into fragments and
1928  * send them out the individual links.
1929  */
ppp_mp_explode(struct ppp * ppp,struct sk_buff * skb)1930 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1931 {
1932 	int len, totlen;
1933 	int i, bits, hdrlen, mtu;
1934 	int flen;
1935 	int navail, nfree, nzero;
1936 	int nbigger;
1937 	int totspeed;
1938 	int totfree;
1939 	unsigned char *p, *q;
1940 	struct list_head *list;
1941 	struct channel *pch;
1942 	struct sk_buff *frag;
1943 	struct ppp_channel *chan;
1944 
1945 	totspeed = 0; /*total bitrate of the bundle*/
1946 	nfree = 0; /* # channels which have no packet already queued */
1947 	navail = 0; /* total # of usable channels (not deregistered) */
1948 	nzero = 0; /* number of channels with zero speed associated*/
1949 	totfree = 0; /*total # of channels available and
1950 				  *having no queued packets before
1951 				  *starting the fragmentation*/
1952 
1953 	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1954 	i = 0;
1955 	list_for_each_entry(pch, &ppp->channels, clist) {
1956 		if (pch->chan) {
1957 			pch->avail = 1;
1958 			navail++;
1959 			pch->speed = pch->chan->speed;
1960 		} else {
1961 			pch->avail = 0;
1962 		}
1963 		if (pch->avail) {
1964 			if (skb_queue_empty(&pch->file.xq) ||
1965 				!pch->had_frag) {
1966 					if (pch->speed == 0)
1967 						nzero++;
1968 					else
1969 						totspeed += pch->speed;
1970 
1971 					pch->avail = 2;
1972 					++nfree;
1973 					++totfree;
1974 				}
1975 			if (!pch->had_frag && i < ppp->nxchan)
1976 				ppp->nxchan = i;
1977 		}
1978 		++i;
1979 	}
1980 	/*
1981 	 * Don't start sending this packet unless at least half of
1982 	 * the channels are free.  This gives much better TCP
1983 	 * performance if we have a lot of channels.
1984 	 */
1985 	if (nfree == 0 || nfree < navail / 2)
1986 		return 0; /* can't take now, leave it in xmit_pending */
1987 
1988 	/* Do protocol field compression */
1989 	p = skb->data;
1990 	len = skb->len;
1991 	if (*p == 0 && mp_protocol_compress) {
1992 		++p;
1993 		--len;
1994 	}
1995 
1996 	totlen = len;
1997 	nbigger = len % nfree;
1998 
1999 	/* skip to the channel after the one we last used
2000 	   and start at that one */
2001 	list = &ppp->channels;
2002 	for (i = 0; i < ppp->nxchan; ++i) {
2003 		list = list->next;
2004 		if (list == &ppp->channels) {
2005 			i = 0;
2006 			break;
2007 		}
2008 	}
2009 
2010 	/* create a fragment for each channel */
2011 	bits = B;
2012 	while (len > 0) {
2013 		list = list->next;
2014 		if (list == &ppp->channels) {
2015 			i = 0;
2016 			continue;
2017 		}
2018 		pch = list_entry(list, struct channel, clist);
2019 		++i;
2020 		if (!pch->avail)
2021 			continue;
2022 
2023 		/*
2024 		 * Skip this channel if it has a fragment pending already and
2025 		 * we haven't given a fragment to all of the free channels.
2026 		 */
2027 		if (pch->avail == 1) {
2028 			if (nfree > 0)
2029 				continue;
2030 		} else {
2031 			pch->avail = 1;
2032 		}
2033 
2034 		/* check the channel's mtu and whether it is still attached. */
2035 		spin_lock(&pch->downl);
2036 		if (pch->chan == NULL) {
2037 			/* can't use this channel, it's being deregistered */
2038 			if (pch->speed == 0)
2039 				nzero--;
2040 			else
2041 				totspeed -= pch->speed;
2042 
2043 			spin_unlock(&pch->downl);
2044 			pch->avail = 0;
2045 			totlen = len;
2046 			totfree--;
2047 			nfree--;
2048 			if (--navail == 0)
2049 				break;
2050 			continue;
2051 		}
2052 
2053 		/*
2054 		*if the channel speed is not set divide
2055 		*the packet evenly among the free channels;
2056 		*otherwise divide it according to the speed
2057 		*of the channel we are going to transmit on
2058 		*/
2059 		flen = len;
2060 		if (nfree > 0) {
2061 			if (pch->speed == 0) {
2062 				flen = len/nfree;
2063 				if (nbigger > 0) {
2064 					flen++;
2065 					nbigger--;
2066 				}
2067 			} else {
2068 				flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2069 					((totspeed*totfree)/pch->speed)) - hdrlen;
2070 				if (nbigger > 0) {
2071 					flen += ((totfree - nzero)*pch->speed)/totspeed;
2072 					nbigger -= ((totfree - nzero)*pch->speed)/
2073 							totspeed;
2074 				}
2075 			}
2076 			nfree--;
2077 		}
2078 
2079 		/*
2080 		 *check if we are on the last channel or
2081 		 *we exceded the length of the data to
2082 		 *fragment
2083 		 */
2084 		if ((nfree <= 0) || (flen > len))
2085 			flen = len;
2086 		/*
2087 		 *it is not worth to tx on slow channels:
2088 		 *in that case from the resulting flen according to the
2089 		 *above formula will be equal or less than zero.
2090 		 *Skip the channel in this case
2091 		 */
2092 		if (flen <= 0) {
2093 			pch->avail = 2;
2094 			spin_unlock(&pch->downl);
2095 			continue;
2096 		}
2097 
2098 		/*
2099 		 * hdrlen includes the 2-byte PPP protocol field, but the
2100 		 * MTU counts only the payload excluding the protocol field.
2101 		 * (RFC1661 Section 2)
2102 		 */
2103 		mtu = pch->chan->mtu - (hdrlen - 2);
2104 		if (mtu < 4)
2105 			mtu = 4;
2106 		if (flen > mtu)
2107 			flen = mtu;
2108 		if (flen == len)
2109 			bits |= E;
2110 		frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2111 		if (!frag)
2112 			goto noskb;
2113 		q = skb_put(frag, flen + hdrlen);
2114 
2115 		/* make the MP header */
2116 		put_unaligned_be16(PPP_MP, q);
2117 		if (ppp->flags & SC_MP_XSHORTSEQ) {
2118 			q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2119 			q[3] = ppp->nxseq;
2120 		} else {
2121 			q[2] = bits;
2122 			q[3] = ppp->nxseq >> 16;
2123 			q[4] = ppp->nxseq >> 8;
2124 			q[5] = ppp->nxseq;
2125 		}
2126 
2127 		memcpy(q + hdrlen, p, flen);
2128 
2129 		/* try to send it down the channel */
2130 		chan = pch->chan;
2131 		if (!skb_queue_empty(&pch->file.xq) ||
2132 			!chan->ops->start_xmit(chan, frag))
2133 			skb_queue_tail(&pch->file.xq, frag);
2134 		pch->had_frag = 1;
2135 		p += flen;
2136 		len -= flen;
2137 		++ppp->nxseq;
2138 		bits = 0;
2139 		spin_unlock(&pch->downl);
2140 	}
2141 	ppp->nxchan = i;
2142 
2143 	return 1;
2144 
2145  noskb:
2146 	spin_unlock(&pch->downl);
2147 	if (ppp->debug & 1)
2148 		netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2149 	++ppp->dev->stats.tx_errors;
2150 	++ppp->nxseq;
2151 	return 1;	/* abandon the frame */
2152 }
2153 #endif /* CONFIG_PPP_MULTILINK */
2154 
2155 /* Try to send data out on a channel */
__ppp_channel_push(struct channel * pch)2156 static void __ppp_channel_push(struct channel *pch)
2157 {
2158 	struct sk_buff *skb;
2159 	struct ppp *ppp;
2160 
2161 	spin_lock(&pch->downl);
2162 	if (pch->chan) {
2163 		while (!skb_queue_empty(&pch->file.xq)) {
2164 			skb = skb_dequeue(&pch->file.xq);
2165 			if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2166 				/* put the packet back and try again later */
2167 				skb_queue_head(&pch->file.xq, skb);
2168 				break;
2169 			}
2170 		}
2171 	} else {
2172 		/* channel got deregistered */
2173 		skb_queue_purge(&pch->file.xq);
2174 	}
2175 	spin_unlock(&pch->downl);
2176 	/* see if there is anything from the attached unit to be sent */
2177 	if (skb_queue_empty(&pch->file.xq)) {
2178 		ppp = pch->ppp;
2179 		if (ppp)
2180 			__ppp_xmit_process(ppp, NULL);
2181 	}
2182 }
2183 
ppp_channel_push(struct channel * pch)2184 static void ppp_channel_push(struct channel *pch)
2185 {
2186 	read_lock_bh(&pch->upl);
2187 	if (pch->ppp) {
2188 		(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2189 		__ppp_channel_push(pch);
2190 		(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2191 	} else {
2192 		__ppp_channel_push(pch);
2193 	}
2194 	read_unlock_bh(&pch->upl);
2195 }
2196 
2197 /*
2198  * Receive-side routines.
2199  */
2200 
2201 struct ppp_mp_skb_parm {
2202 	u32		sequence;
2203 	u8		BEbits;
2204 };
2205 #define PPP_MP_CB(skb)	((struct ppp_mp_skb_parm *)((skb)->cb))
2206 
2207 static inline void
ppp_do_recv(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2208 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2209 {
2210 	ppp_recv_lock(ppp);
2211 	if (!ppp->closing)
2212 		ppp_receive_frame(ppp, skb, pch);
2213 	else
2214 		kfree_skb(skb);
2215 	ppp_recv_unlock(ppp);
2216 }
2217 
2218 /**
2219  * __ppp_decompress_proto - Decompress protocol field, slim version.
2220  * @skb: Socket buffer where protocol field should be decompressed. It must have
2221  *	 at least 1 byte of head room and 1 byte of linear data. First byte of
2222  *	 data must be a protocol field byte.
2223  *
2224  * Decompress protocol field in PPP header if it's compressed, e.g. when
2225  * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2226  * length are done in this function.
2227  */
__ppp_decompress_proto(struct sk_buff * skb)2228 static void __ppp_decompress_proto(struct sk_buff *skb)
2229 {
2230 	if (skb->data[0] & 0x01)
2231 		*(u8 *)skb_push(skb, 1) = 0x00;
2232 }
2233 
2234 /**
2235  * ppp_decompress_proto - Check skb data room and decompress protocol field.
2236  * @skb: Socket buffer where protocol field should be decompressed. First byte
2237  *	 of data must be a protocol field byte.
2238  *
2239  * Decompress protocol field in PPP header if it's compressed, e.g. when
2240  * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2241  * sure that skb data room is sufficient for Protocol field, before and after
2242  * decompression.
2243  *
2244  * Return: true - decompressed successfully, false - not enough room in skb.
2245  */
ppp_decompress_proto(struct sk_buff * skb)2246 static bool ppp_decompress_proto(struct sk_buff *skb)
2247 {
2248 	/* At least one byte should be present (if protocol is compressed) */
2249 	if (!pskb_may_pull(skb, 1))
2250 		return false;
2251 
2252 	__ppp_decompress_proto(skb);
2253 
2254 	/* Protocol field should occupy 2 bytes when not compressed */
2255 	return pskb_may_pull(skb, 2);
2256 }
2257 
2258 /* Attempt to handle a frame via. a bridged channel, if one exists.
2259  * If the channel is bridged, the frame is consumed by the bridge.
2260  * If not, the caller must handle the frame by normal recv mechanisms.
2261  * Returns true if the frame is consumed, false otherwise.
2262  */
ppp_channel_bridge_input(struct channel * pch,struct sk_buff * skb)2263 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2264 {
2265 	struct channel *pchb;
2266 
2267 	rcu_read_lock();
2268 	pchb = rcu_dereference(pch->bridge);
2269 	if (!pchb)
2270 		goto out_rcu;
2271 
2272 	spin_lock_bh(&pchb->downl);
2273 	if (!pchb->chan) {
2274 		/* channel got unregistered */
2275 		kfree_skb(skb);
2276 		goto outl;
2277 	}
2278 
2279 	skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2280 	if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2281 		kfree_skb(skb);
2282 
2283 outl:
2284 	spin_unlock_bh(&pchb->downl);
2285 out_rcu:
2286 	rcu_read_unlock();
2287 
2288 	/* If pchb is set then we've consumed the packet */
2289 	return !!pchb;
2290 }
2291 
2292 void
ppp_input(struct ppp_channel * chan,struct sk_buff * skb)2293 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2294 {
2295 	struct channel *pch = chan->ppp;
2296 	int proto;
2297 
2298 	if (!pch) {
2299 		kfree_skb(skb);
2300 		return;
2301 	}
2302 
2303 	/* If the channel is bridged, transmit via. bridge */
2304 	if (ppp_channel_bridge_input(pch, skb))
2305 		return;
2306 
2307 	read_lock_bh(&pch->upl);
2308 	if (!ppp_decompress_proto(skb)) {
2309 		kfree_skb(skb);
2310 		if (pch->ppp) {
2311 			++pch->ppp->dev->stats.rx_length_errors;
2312 			ppp_receive_error(pch->ppp);
2313 		}
2314 		goto done;
2315 	}
2316 
2317 	proto = PPP_PROTO(skb);
2318 	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2319 		/* put it on the channel queue */
2320 		skb_queue_tail(&pch->file.rq, skb);
2321 		/* drop old frames if queue too long */
2322 		while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2323 		       (skb = skb_dequeue(&pch->file.rq)))
2324 			kfree_skb(skb);
2325 		wake_up_interruptible(&pch->file.rwait);
2326 	} else {
2327 		ppp_do_recv(pch->ppp, skb, pch);
2328 	}
2329 
2330 done:
2331 	read_unlock_bh(&pch->upl);
2332 }
2333 
2334 /* Put a 0-length skb in the receive queue as an error indication */
2335 void
ppp_input_error(struct ppp_channel * chan,int code)2336 ppp_input_error(struct ppp_channel *chan, int code)
2337 {
2338 	struct channel *pch = chan->ppp;
2339 	struct sk_buff *skb;
2340 
2341 	if (!pch)
2342 		return;
2343 
2344 	read_lock_bh(&pch->upl);
2345 	if (pch->ppp) {
2346 		skb = alloc_skb(0, GFP_ATOMIC);
2347 		if (skb) {
2348 			skb->len = 0;		/* probably unnecessary */
2349 			skb->cb[0] = code;
2350 			ppp_do_recv(pch->ppp, skb, pch);
2351 		}
2352 	}
2353 	read_unlock_bh(&pch->upl);
2354 }
2355 
2356 /*
2357  * We come in here to process a received frame.
2358  * The receive side of the ppp unit is locked.
2359  */
2360 static void
ppp_receive_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2361 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2362 {
2363 	/* note: a 0-length skb is used as an error indication */
2364 	if (skb->len > 0) {
2365 		skb_checksum_complete_unset(skb);
2366 #ifdef CONFIG_PPP_MULTILINK
2367 		/* XXX do channel-level decompression here */
2368 		if (PPP_PROTO(skb) == PPP_MP)
2369 			ppp_receive_mp_frame(ppp, skb, pch);
2370 		else
2371 #endif /* CONFIG_PPP_MULTILINK */
2372 			ppp_receive_nonmp_frame(ppp, skb);
2373 	} else {
2374 		kfree_skb(skb);
2375 		ppp_receive_error(ppp);
2376 	}
2377 }
2378 
2379 static void
ppp_receive_error(struct ppp * ppp)2380 ppp_receive_error(struct ppp *ppp)
2381 {
2382 	++ppp->dev->stats.rx_errors;
2383 	if (ppp->vj)
2384 		slhc_toss(ppp->vj);
2385 }
2386 
2387 static void
ppp_receive_nonmp_frame(struct ppp * ppp,struct sk_buff * skb)2388 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2389 {
2390 	struct sk_buff *ns;
2391 	int proto, len, npi;
2392 
2393 	/*
2394 	 * Decompress the frame, if compressed.
2395 	 * Note that some decompressors need to see uncompressed frames
2396 	 * that come in as well as compressed frames.
2397 	 */
2398 	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2399 	    (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2400 		skb = ppp_decompress_frame(ppp, skb);
2401 
2402 	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2403 		goto err;
2404 
2405 	/* At this point the "Protocol" field MUST be decompressed, either in
2406 	 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2407 	 */
2408 	proto = PPP_PROTO(skb);
2409 	switch (proto) {
2410 	case PPP_VJC_COMP:
2411 		/* decompress VJ compressed packets */
2412 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2413 			goto err;
2414 
2415 		if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2416 			/* copy to a new sk_buff with more tailroom */
2417 			ns = dev_alloc_skb(skb->len + 128);
2418 			if (!ns) {
2419 				netdev_err(ppp->dev, "PPP: no memory "
2420 					   "(VJ decomp)\n");
2421 				goto err;
2422 			}
2423 			skb_reserve(ns, 2);
2424 			skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2425 			consume_skb(skb);
2426 			skb = ns;
2427 		}
2428 		else
2429 			skb->ip_summed = CHECKSUM_NONE;
2430 
2431 		len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2432 		if (len <= 0) {
2433 			netdev_printk(KERN_DEBUG, ppp->dev,
2434 				      "PPP: VJ decompression error\n");
2435 			goto err;
2436 		}
2437 		len += 2;
2438 		if (len > skb->len)
2439 			skb_put(skb, len - skb->len);
2440 		else if (len < skb->len)
2441 			skb_trim(skb, len);
2442 		proto = PPP_IP;
2443 		break;
2444 
2445 	case PPP_VJC_UNCOMP:
2446 		if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2447 			goto err;
2448 
2449 		/* Until we fix the decompressor need to make sure
2450 		 * data portion is linear.
2451 		 */
2452 		if (!pskb_may_pull(skb, skb->len))
2453 			goto err;
2454 
2455 		if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2456 			netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2457 			goto err;
2458 		}
2459 		proto = PPP_IP;
2460 		break;
2461 
2462 	case PPP_CCP:
2463 		ppp_ccp_peek(ppp, skb, 1);
2464 		break;
2465 	}
2466 
2467 	++ppp->stats64.rx_packets;
2468 	ppp->stats64.rx_bytes += skb->len - 2;
2469 
2470 	npi = proto_to_npindex(proto);
2471 	if (npi < 0) {
2472 		/* control or unknown frame - pass it to pppd */
2473 		skb_queue_tail(&ppp->file.rq, skb);
2474 		/* limit queue length by dropping old frames */
2475 		while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2476 		       (skb = skb_dequeue(&ppp->file.rq)))
2477 			kfree_skb(skb);
2478 		/* wake up any process polling or blocking on read */
2479 		wake_up_interruptible(&ppp->file.rwait);
2480 
2481 	} else {
2482 		/* network protocol frame - give it to the kernel */
2483 
2484 #ifdef CONFIG_PPP_FILTER
2485 		/* check if the packet passes the pass and active filters */
2486 		/* the filter instructions are constructed assuming
2487 		   a four-byte PPP header on each packet */
2488 		if (ppp->pass_filter || ppp->active_filter) {
2489 			if (skb_unclone(skb, GFP_ATOMIC))
2490 				goto err;
2491 
2492 			*(u8 *)skb_push(skb, 2) = 0;
2493 			if (ppp->pass_filter &&
2494 			    bpf_prog_run(ppp->pass_filter, skb) == 0) {
2495 				if (ppp->debug & 1)
2496 					netdev_printk(KERN_DEBUG, ppp->dev,
2497 						      "PPP: inbound frame "
2498 						      "not passed\n");
2499 				kfree_skb(skb);
2500 				return;
2501 			}
2502 			if (!(ppp->active_filter &&
2503 			      bpf_prog_run(ppp->active_filter, skb) == 0))
2504 				ppp->last_recv = jiffies;
2505 			__skb_pull(skb, 2);
2506 		} else
2507 #endif /* CONFIG_PPP_FILTER */
2508 			ppp->last_recv = jiffies;
2509 
2510 		if ((ppp->dev->flags & IFF_UP) == 0 ||
2511 		    ppp->npmode[npi] != NPMODE_PASS) {
2512 			kfree_skb(skb);
2513 		} else {
2514 			/* chop off protocol */
2515 			skb_pull_rcsum(skb, 2);
2516 			skb->dev = ppp->dev;
2517 			skb->protocol = htons(npindex_to_ethertype[npi]);
2518 			skb_reset_mac_header(skb);
2519 			skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2520 						      dev_net(ppp->dev)));
2521 			netif_rx(skb);
2522 		}
2523 	}
2524 	return;
2525 
2526  err:
2527 	kfree_skb(skb);
2528 	ppp_receive_error(ppp);
2529 }
2530 
2531 static struct sk_buff *
ppp_decompress_frame(struct ppp * ppp,struct sk_buff * skb)2532 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2533 {
2534 	int proto = PPP_PROTO(skb);
2535 	struct sk_buff *ns;
2536 	int len;
2537 
2538 	/* Until we fix all the decompressor's need to make sure
2539 	 * data portion is linear.
2540 	 */
2541 	if (!pskb_may_pull(skb, skb->len))
2542 		goto err;
2543 
2544 	if (proto == PPP_COMP) {
2545 		int obuff_size;
2546 
2547 		switch(ppp->rcomp->compress_proto) {
2548 		case CI_MPPE:
2549 			obuff_size = ppp->mru + PPP_HDRLEN + 1;
2550 			break;
2551 		default:
2552 			obuff_size = ppp->mru + PPP_HDRLEN;
2553 			break;
2554 		}
2555 
2556 		ns = dev_alloc_skb(obuff_size);
2557 		if (!ns) {
2558 			netdev_err(ppp->dev, "ppp_decompress_frame: "
2559 				   "no memory\n");
2560 			goto err;
2561 		}
2562 		/* the decompressor still expects the A/C bytes in the hdr */
2563 		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2564 				skb->len + 2, ns->data, obuff_size);
2565 		if (len < 0) {
2566 			/* Pass the compressed frame to pppd as an
2567 			   error indication. */
2568 			if (len == DECOMP_FATALERROR)
2569 				ppp->rstate |= SC_DC_FERROR;
2570 			kfree_skb(ns);
2571 			goto err;
2572 		}
2573 
2574 		consume_skb(skb);
2575 		skb = ns;
2576 		skb_put(skb, len);
2577 		skb_pull(skb, 2);	/* pull off the A/C bytes */
2578 
2579 		/* Don't call __ppp_decompress_proto() here, but instead rely on
2580 		 * corresponding algo (mppe/bsd/deflate) to decompress it.
2581 		 */
2582 	} else {
2583 		/* Uncompressed frame - pass to decompressor so it
2584 		   can update its dictionary if necessary. */
2585 		if (ppp->rcomp->incomp)
2586 			ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2587 					   skb->len + 2);
2588 	}
2589 
2590 	return skb;
2591 
2592  err:
2593 	ppp->rstate |= SC_DC_ERROR;
2594 	ppp_receive_error(ppp);
2595 	return skb;
2596 }
2597 
2598 #ifdef CONFIG_PPP_MULTILINK
2599 /*
2600  * Receive a multilink frame.
2601  * We put it on the reconstruction queue and then pull off
2602  * as many completed frames as we can.
2603  */
2604 static void
ppp_receive_mp_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2605 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2606 {
2607 	u32 mask, seq;
2608 	struct channel *ch;
2609 	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2610 
2611 	if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2612 		goto err;		/* no good, throw it away */
2613 
2614 	/* Decode sequence number and begin/end bits */
2615 	if (ppp->flags & SC_MP_SHORTSEQ) {
2616 		seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2617 		mask = 0xfff;
2618 	} else {
2619 		seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2620 		mask = 0xffffff;
2621 	}
2622 	PPP_MP_CB(skb)->BEbits = skb->data[2];
2623 	skb_pull(skb, mphdrlen);	/* pull off PPP and MP headers */
2624 
2625 	/*
2626 	 * Do protocol ID decompression on the first fragment of each packet.
2627 	 * We have to do that here, because ppp_receive_nonmp_frame() expects
2628 	 * decompressed protocol field.
2629 	 */
2630 	if (PPP_MP_CB(skb)->BEbits & B)
2631 		__ppp_decompress_proto(skb);
2632 
2633 	/*
2634 	 * Expand sequence number to 32 bits, making it as close
2635 	 * as possible to ppp->minseq.
2636 	 */
2637 	seq |= ppp->minseq & ~mask;
2638 	if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2639 		seq += mask + 1;
2640 	else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2641 		seq -= mask + 1;	/* should never happen */
2642 	PPP_MP_CB(skb)->sequence = seq;
2643 	pch->lastseq = seq;
2644 
2645 	/*
2646 	 * If this packet comes before the next one we were expecting,
2647 	 * drop it.
2648 	 */
2649 	if (seq_before(seq, ppp->nextseq)) {
2650 		kfree_skb(skb);
2651 		++ppp->dev->stats.rx_dropped;
2652 		ppp_receive_error(ppp);
2653 		return;
2654 	}
2655 
2656 	/*
2657 	 * Reevaluate minseq, the minimum over all channels of the
2658 	 * last sequence number received on each channel.  Because of
2659 	 * the increasing sequence number rule, we know that any fragment
2660 	 * before `minseq' which hasn't arrived is never going to arrive.
2661 	 * The list of channels can't change because we have the receive
2662 	 * side of the ppp unit locked.
2663 	 */
2664 	list_for_each_entry(ch, &ppp->channels, clist) {
2665 		if (seq_before(ch->lastseq, seq))
2666 			seq = ch->lastseq;
2667 	}
2668 	if (seq_before(ppp->minseq, seq))
2669 		ppp->minseq = seq;
2670 
2671 	/* Put the fragment on the reconstruction queue */
2672 	ppp_mp_insert(ppp, skb);
2673 
2674 	/* If the queue is getting long, don't wait any longer for packets
2675 	   before the start of the queue. */
2676 	if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2677 		struct sk_buff *mskb = skb_peek(&ppp->mrq);
2678 		if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2679 			ppp->minseq = PPP_MP_CB(mskb)->sequence;
2680 	}
2681 
2682 	/* Pull completed packets off the queue and receive them. */
2683 	while ((skb = ppp_mp_reconstruct(ppp))) {
2684 		if (pskb_may_pull(skb, 2))
2685 			ppp_receive_nonmp_frame(ppp, skb);
2686 		else {
2687 			++ppp->dev->stats.rx_length_errors;
2688 			kfree_skb(skb);
2689 			ppp_receive_error(ppp);
2690 		}
2691 	}
2692 
2693 	return;
2694 
2695  err:
2696 	kfree_skb(skb);
2697 	ppp_receive_error(ppp);
2698 }
2699 
2700 /*
2701  * Insert a fragment on the MP reconstruction queue.
2702  * The queue is ordered by increasing sequence number.
2703  */
2704 static void
ppp_mp_insert(struct ppp * ppp,struct sk_buff * skb)2705 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2706 {
2707 	struct sk_buff *p;
2708 	struct sk_buff_head *list = &ppp->mrq;
2709 	u32 seq = PPP_MP_CB(skb)->sequence;
2710 
2711 	/* N.B. we don't need to lock the list lock because we have the
2712 	   ppp unit receive-side lock. */
2713 	skb_queue_walk(list, p) {
2714 		if (seq_before(seq, PPP_MP_CB(p)->sequence))
2715 			break;
2716 	}
2717 	__skb_queue_before(list, p, skb);
2718 }
2719 
2720 /*
2721  * Reconstruct a packet from the MP fragment queue.
2722  * We go through increasing sequence numbers until we find a
2723  * complete packet, or we get to the sequence number for a fragment
2724  * which hasn't arrived but might still do so.
2725  */
2726 static struct sk_buff *
ppp_mp_reconstruct(struct ppp * ppp)2727 ppp_mp_reconstruct(struct ppp *ppp)
2728 {
2729 	u32 seq = ppp->nextseq;
2730 	u32 minseq = ppp->minseq;
2731 	struct sk_buff_head *list = &ppp->mrq;
2732 	struct sk_buff *p, *tmp;
2733 	struct sk_buff *head, *tail;
2734 	struct sk_buff *skb = NULL;
2735 	int lost = 0, len = 0;
2736 
2737 	if (ppp->mrru == 0)	/* do nothing until mrru is set */
2738 		return NULL;
2739 	head = __skb_peek(list);
2740 	tail = NULL;
2741 	skb_queue_walk_safe(list, p, tmp) {
2742 	again:
2743 		if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2744 			/* this can't happen, anyway ignore the skb */
2745 			netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2746 				   "seq %u < %u\n",
2747 				   PPP_MP_CB(p)->sequence, seq);
2748 			__skb_unlink(p, list);
2749 			kfree_skb(p);
2750 			continue;
2751 		}
2752 		if (PPP_MP_CB(p)->sequence != seq) {
2753 			u32 oldseq;
2754 			/* Fragment `seq' is missing.  If it is after
2755 			   minseq, it might arrive later, so stop here. */
2756 			if (seq_after(seq, minseq))
2757 				break;
2758 			/* Fragment `seq' is lost, keep going. */
2759 			lost = 1;
2760 			oldseq = seq;
2761 			seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2762 				minseq + 1: PPP_MP_CB(p)->sequence;
2763 
2764 			if (ppp->debug & 1)
2765 				netdev_printk(KERN_DEBUG, ppp->dev,
2766 					      "lost frag %u..%u\n",
2767 					      oldseq, seq-1);
2768 
2769 			goto again;
2770 		}
2771 
2772 		/*
2773 		 * At this point we know that all the fragments from
2774 		 * ppp->nextseq to seq are either present or lost.
2775 		 * Also, there are no complete packets in the queue
2776 		 * that have no missing fragments and end before this
2777 		 * fragment.
2778 		 */
2779 
2780 		/* B bit set indicates this fragment starts a packet */
2781 		if (PPP_MP_CB(p)->BEbits & B) {
2782 			head = p;
2783 			lost = 0;
2784 			len = 0;
2785 		}
2786 
2787 		len += p->len;
2788 
2789 		/* Got a complete packet yet? */
2790 		if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2791 		    (PPP_MP_CB(head)->BEbits & B)) {
2792 			if (len > ppp->mrru + 2) {
2793 				++ppp->dev->stats.rx_length_errors;
2794 				netdev_printk(KERN_DEBUG, ppp->dev,
2795 					      "PPP: reconstructed packet"
2796 					      " is too long (%d)\n", len);
2797 			} else {
2798 				tail = p;
2799 				break;
2800 			}
2801 			ppp->nextseq = seq + 1;
2802 		}
2803 
2804 		/*
2805 		 * If this is the ending fragment of a packet,
2806 		 * and we haven't found a complete valid packet yet,
2807 		 * we can discard up to and including this fragment.
2808 		 */
2809 		if (PPP_MP_CB(p)->BEbits & E) {
2810 			struct sk_buff *tmp2;
2811 
2812 			skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2813 				if (ppp->debug & 1)
2814 					netdev_printk(KERN_DEBUG, ppp->dev,
2815 						      "discarding frag %u\n",
2816 						      PPP_MP_CB(p)->sequence);
2817 				__skb_unlink(p, list);
2818 				kfree_skb(p);
2819 			}
2820 			head = skb_peek(list);
2821 			if (!head)
2822 				break;
2823 		}
2824 		++seq;
2825 	}
2826 
2827 	/* If we have a complete packet, copy it all into one skb. */
2828 	if (tail != NULL) {
2829 		/* If we have discarded any fragments,
2830 		   signal a receive error. */
2831 		if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2832 			skb_queue_walk_safe(list, p, tmp) {
2833 				if (p == head)
2834 					break;
2835 				if (ppp->debug & 1)
2836 					netdev_printk(KERN_DEBUG, ppp->dev,
2837 						      "discarding frag %u\n",
2838 						      PPP_MP_CB(p)->sequence);
2839 				__skb_unlink(p, list);
2840 				kfree_skb(p);
2841 			}
2842 
2843 			if (ppp->debug & 1)
2844 				netdev_printk(KERN_DEBUG, ppp->dev,
2845 					      "  missed pkts %u..%u\n",
2846 					      ppp->nextseq,
2847 					      PPP_MP_CB(head)->sequence-1);
2848 			++ppp->dev->stats.rx_dropped;
2849 			ppp_receive_error(ppp);
2850 		}
2851 
2852 		skb = head;
2853 		if (head != tail) {
2854 			struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2855 			p = skb_queue_next(list, head);
2856 			__skb_unlink(skb, list);
2857 			skb_queue_walk_from_safe(list, p, tmp) {
2858 				__skb_unlink(p, list);
2859 				*fragpp = p;
2860 				p->next = NULL;
2861 				fragpp = &p->next;
2862 
2863 				skb->len += p->len;
2864 				skb->data_len += p->len;
2865 				skb->truesize += p->truesize;
2866 
2867 				if (p == tail)
2868 					break;
2869 			}
2870 		} else {
2871 			__skb_unlink(skb, list);
2872 		}
2873 
2874 		ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2875 	}
2876 
2877 	return skb;
2878 }
2879 #endif /* CONFIG_PPP_MULTILINK */
2880 
2881 /*
2882  * Channel interface.
2883  */
2884 
2885 /* Create a new, unattached ppp channel. */
ppp_register_channel(struct ppp_channel * chan)2886 int ppp_register_channel(struct ppp_channel *chan)
2887 {
2888 	return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2889 }
2890 
2891 /* Create a new, unattached ppp channel for specified net. */
ppp_register_net_channel(struct net * net,struct ppp_channel * chan)2892 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2893 {
2894 	struct channel *pch;
2895 	struct ppp_net *pn;
2896 
2897 	pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2898 	if (!pch)
2899 		return -ENOMEM;
2900 
2901 	pn = ppp_pernet(net);
2902 
2903 	pch->ppp = NULL;
2904 	pch->chan = chan;
2905 	pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2906 	chan->ppp = pch;
2907 	init_ppp_file(&pch->file, CHANNEL);
2908 	pch->file.hdrlen = chan->hdrlen;
2909 #ifdef CONFIG_PPP_MULTILINK
2910 	pch->lastseq = -1;
2911 #endif /* CONFIG_PPP_MULTILINK */
2912 	init_rwsem(&pch->chan_sem);
2913 	spin_lock_init(&pch->downl);
2914 	rwlock_init(&pch->upl);
2915 
2916 	spin_lock_bh(&pn->all_channels_lock);
2917 	pch->file.index = ++pn->last_channel_index;
2918 	list_add(&pch->list, &pn->new_channels);
2919 	atomic_inc(&channel_count);
2920 	spin_unlock_bh(&pn->all_channels_lock);
2921 
2922 	return 0;
2923 }
2924 
2925 /*
2926  * Return the index of a channel.
2927  */
ppp_channel_index(struct ppp_channel * chan)2928 int ppp_channel_index(struct ppp_channel *chan)
2929 {
2930 	struct channel *pch = chan->ppp;
2931 
2932 	if (pch)
2933 		return pch->file.index;
2934 	return -1;
2935 }
2936 
2937 /*
2938  * Return the PPP unit number to which a channel is connected.
2939  */
ppp_unit_number(struct ppp_channel * chan)2940 int ppp_unit_number(struct ppp_channel *chan)
2941 {
2942 	struct channel *pch = chan->ppp;
2943 	int unit = -1;
2944 
2945 	if (pch) {
2946 		read_lock_bh(&pch->upl);
2947 		if (pch->ppp)
2948 			unit = pch->ppp->file.index;
2949 		read_unlock_bh(&pch->upl);
2950 	}
2951 	return unit;
2952 }
2953 
2954 /*
2955  * Return the PPP device interface name of a channel.
2956  */
ppp_dev_name(struct ppp_channel * chan)2957 char *ppp_dev_name(struct ppp_channel *chan)
2958 {
2959 	struct channel *pch = chan->ppp;
2960 	char *name = NULL;
2961 
2962 	if (pch) {
2963 		read_lock_bh(&pch->upl);
2964 		if (pch->ppp && pch->ppp->dev)
2965 			name = pch->ppp->dev->name;
2966 		read_unlock_bh(&pch->upl);
2967 	}
2968 	return name;
2969 }
2970 
2971 
2972 /*
2973  * Disconnect a channel from the generic layer.
2974  * This must be called in process context.
2975  */
2976 void
ppp_unregister_channel(struct ppp_channel * chan)2977 ppp_unregister_channel(struct ppp_channel *chan)
2978 {
2979 	struct channel *pch = chan->ppp;
2980 	struct ppp_net *pn;
2981 
2982 	if (!pch)
2983 		return;		/* should never happen */
2984 
2985 	chan->ppp = NULL;
2986 
2987 	/*
2988 	 * This ensures that we have returned from any calls into
2989 	 * the channel's start_xmit or ioctl routine before we proceed.
2990 	 */
2991 	down_write(&pch->chan_sem);
2992 	spin_lock_bh(&pch->downl);
2993 	pch->chan = NULL;
2994 	spin_unlock_bh(&pch->downl);
2995 	up_write(&pch->chan_sem);
2996 	ppp_disconnect_channel(pch);
2997 
2998 	pn = ppp_pernet(pch->chan_net);
2999 	spin_lock_bh(&pn->all_channels_lock);
3000 	list_del(&pch->list);
3001 	spin_unlock_bh(&pn->all_channels_lock);
3002 
3003 	ppp_unbridge_channels(pch);
3004 
3005 	pch->file.dead = 1;
3006 	wake_up_interruptible(&pch->file.rwait);
3007 
3008 	if (refcount_dec_and_test(&pch->file.refcnt))
3009 		ppp_destroy_channel(pch);
3010 }
3011 
3012 /*
3013  * Callback from a channel when it can accept more to transmit.
3014  * This should be called at BH/softirq level, not interrupt level.
3015  */
3016 void
ppp_output_wakeup(struct ppp_channel * chan)3017 ppp_output_wakeup(struct ppp_channel *chan)
3018 {
3019 	struct channel *pch = chan->ppp;
3020 
3021 	if (!pch)
3022 		return;
3023 	ppp_channel_push(pch);
3024 }
3025 
3026 /*
3027  * Compression control.
3028  */
3029 
3030 /* Process the PPPIOCSCOMPRESS ioctl. */
3031 static int
ppp_set_compress(struct ppp * ppp,struct ppp_option_data * data)3032 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3033 {
3034 	int err = -EFAULT;
3035 	struct compressor *cp, *ocomp;
3036 	void *state, *ostate;
3037 	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3038 
3039 	if (data->length > CCP_MAX_OPTION_LENGTH)
3040 		goto out;
3041 	if (copy_from_user(ccp_option, data->ptr, data->length))
3042 		goto out;
3043 
3044 	err = -EINVAL;
3045 	if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3046 		goto out;
3047 
3048 	cp = try_then_request_module(
3049 		find_compressor(ccp_option[0]),
3050 		"ppp-compress-%d", ccp_option[0]);
3051 	if (!cp)
3052 		goto out;
3053 
3054 	err = -ENOBUFS;
3055 	if (data->transmit) {
3056 		state = cp->comp_alloc(ccp_option, data->length);
3057 		if (state) {
3058 			ppp_xmit_lock(ppp);
3059 			ppp->xstate &= ~SC_COMP_RUN;
3060 			ocomp = ppp->xcomp;
3061 			ostate = ppp->xc_state;
3062 			ppp->xcomp = cp;
3063 			ppp->xc_state = state;
3064 			ppp_xmit_unlock(ppp);
3065 			if (ostate) {
3066 				ocomp->comp_free(ostate);
3067 				module_put(ocomp->owner);
3068 			}
3069 			err = 0;
3070 		} else
3071 			module_put(cp->owner);
3072 
3073 	} else {
3074 		state = cp->decomp_alloc(ccp_option, data->length);
3075 		if (state) {
3076 			ppp_recv_lock(ppp);
3077 			ppp->rstate &= ~SC_DECOMP_RUN;
3078 			ocomp = ppp->rcomp;
3079 			ostate = ppp->rc_state;
3080 			ppp->rcomp = cp;
3081 			ppp->rc_state = state;
3082 			ppp_recv_unlock(ppp);
3083 			if (ostate) {
3084 				ocomp->decomp_free(ostate);
3085 				module_put(ocomp->owner);
3086 			}
3087 			err = 0;
3088 		} else
3089 			module_put(cp->owner);
3090 	}
3091 
3092  out:
3093 	return err;
3094 }
3095 
3096 /*
3097  * Look at a CCP packet and update our state accordingly.
3098  * We assume the caller has the xmit or recv path locked.
3099  */
3100 static void
ppp_ccp_peek(struct ppp * ppp,struct sk_buff * skb,int inbound)3101 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3102 {
3103 	unsigned char *dp;
3104 	int len;
3105 
3106 	if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3107 		return;	/* no header */
3108 	dp = skb->data + 2;
3109 
3110 	switch (CCP_CODE(dp)) {
3111 	case CCP_CONFREQ:
3112 
3113 		/* A ConfReq starts negotiation of compression
3114 		 * in one direction of transmission,
3115 		 * and hence brings it down...but which way?
3116 		 *
3117 		 * Remember:
3118 		 * A ConfReq indicates what the sender would like to receive
3119 		 */
3120 		if(inbound)
3121 			/* He is proposing what I should send */
3122 			ppp->xstate &= ~SC_COMP_RUN;
3123 		else
3124 			/* I am proposing to what he should send */
3125 			ppp->rstate &= ~SC_DECOMP_RUN;
3126 
3127 		break;
3128 
3129 	case CCP_TERMREQ:
3130 	case CCP_TERMACK:
3131 		/*
3132 		 * CCP is going down, both directions of transmission
3133 		 */
3134 		ppp->rstate &= ~SC_DECOMP_RUN;
3135 		ppp->xstate &= ~SC_COMP_RUN;
3136 		break;
3137 
3138 	case CCP_CONFACK:
3139 		if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3140 			break;
3141 		len = CCP_LENGTH(dp);
3142 		if (!pskb_may_pull(skb, len + 2))
3143 			return;		/* too short */
3144 		dp += CCP_HDRLEN;
3145 		len -= CCP_HDRLEN;
3146 		if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3147 			break;
3148 		if (inbound) {
3149 			/* we will start receiving compressed packets */
3150 			if (!ppp->rc_state)
3151 				break;
3152 			if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3153 					ppp->file.index, 0, ppp->mru, ppp->debug)) {
3154 				ppp->rstate |= SC_DECOMP_RUN;
3155 				ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3156 			}
3157 		} else {
3158 			/* we will soon start sending compressed packets */
3159 			if (!ppp->xc_state)
3160 				break;
3161 			if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3162 					ppp->file.index, 0, ppp->debug))
3163 				ppp->xstate |= SC_COMP_RUN;
3164 		}
3165 		break;
3166 
3167 	case CCP_RESETACK:
3168 		/* reset the [de]compressor */
3169 		if ((ppp->flags & SC_CCP_UP) == 0)
3170 			break;
3171 		if (inbound) {
3172 			if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3173 				ppp->rcomp->decomp_reset(ppp->rc_state);
3174 				ppp->rstate &= ~SC_DC_ERROR;
3175 			}
3176 		} else {
3177 			if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3178 				ppp->xcomp->comp_reset(ppp->xc_state);
3179 		}
3180 		break;
3181 	}
3182 }
3183 
3184 /* Free up compression resources. */
3185 static void
ppp_ccp_closed(struct ppp * ppp)3186 ppp_ccp_closed(struct ppp *ppp)
3187 {
3188 	void *xstate, *rstate;
3189 	struct compressor *xcomp, *rcomp;
3190 
3191 	ppp_lock(ppp);
3192 	ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3193 	ppp->xstate = 0;
3194 	xcomp = ppp->xcomp;
3195 	xstate = ppp->xc_state;
3196 	ppp->xc_state = NULL;
3197 	ppp->rstate = 0;
3198 	rcomp = ppp->rcomp;
3199 	rstate = ppp->rc_state;
3200 	ppp->rc_state = NULL;
3201 	ppp_unlock(ppp);
3202 
3203 	if (xstate) {
3204 		xcomp->comp_free(xstate);
3205 		module_put(xcomp->owner);
3206 	}
3207 	if (rstate) {
3208 		rcomp->decomp_free(rstate);
3209 		module_put(rcomp->owner);
3210 	}
3211 }
3212 
3213 /* List of compressors. */
3214 static LIST_HEAD(compressor_list);
3215 static DEFINE_SPINLOCK(compressor_list_lock);
3216 
3217 struct compressor_entry {
3218 	struct list_head list;
3219 	struct compressor *comp;
3220 };
3221 
3222 static struct compressor_entry *
find_comp_entry(int proto)3223 find_comp_entry(int proto)
3224 {
3225 	struct compressor_entry *ce;
3226 
3227 	list_for_each_entry(ce, &compressor_list, list) {
3228 		if (ce->comp->compress_proto == proto)
3229 			return ce;
3230 	}
3231 	return NULL;
3232 }
3233 
3234 /* Register a compressor */
3235 int
ppp_register_compressor(struct compressor * cp)3236 ppp_register_compressor(struct compressor *cp)
3237 {
3238 	struct compressor_entry *ce;
3239 	int ret;
3240 	spin_lock(&compressor_list_lock);
3241 	ret = -EEXIST;
3242 	if (find_comp_entry(cp->compress_proto))
3243 		goto out;
3244 	ret = -ENOMEM;
3245 	ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3246 	if (!ce)
3247 		goto out;
3248 	ret = 0;
3249 	ce->comp = cp;
3250 	list_add(&ce->list, &compressor_list);
3251  out:
3252 	spin_unlock(&compressor_list_lock);
3253 	return ret;
3254 }
3255 
3256 /* Unregister a compressor */
3257 void
ppp_unregister_compressor(struct compressor * cp)3258 ppp_unregister_compressor(struct compressor *cp)
3259 {
3260 	struct compressor_entry *ce;
3261 
3262 	spin_lock(&compressor_list_lock);
3263 	ce = find_comp_entry(cp->compress_proto);
3264 	if (ce && ce->comp == cp) {
3265 		list_del(&ce->list);
3266 		kfree(ce);
3267 	}
3268 	spin_unlock(&compressor_list_lock);
3269 }
3270 
3271 /* Find a compressor. */
3272 static struct compressor *
find_compressor(int type)3273 find_compressor(int type)
3274 {
3275 	struct compressor_entry *ce;
3276 	struct compressor *cp = NULL;
3277 
3278 	spin_lock(&compressor_list_lock);
3279 	ce = find_comp_entry(type);
3280 	if (ce) {
3281 		cp = ce->comp;
3282 		if (!try_module_get(cp->owner))
3283 			cp = NULL;
3284 	}
3285 	spin_unlock(&compressor_list_lock);
3286 	return cp;
3287 }
3288 
3289 /*
3290  * Miscelleneous stuff.
3291  */
3292 
3293 static void
ppp_get_stats(struct ppp * ppp,struct ppp_stats * st)3294 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3295 {
3296 	struct slcompress *vj = ppp->vj;
3297 
3298 	memset(st, 0, sizeof(*st));
3299 	st->p.ppp_ipackets = ppp->stats64.rx_packets;
3300 	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3301 	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3302 	st->p.ppp_opackets = ppp->stats64.tx_packets;
3303 	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3304 	st->p.ppp_obytes = ppp->stats64.tx_bytes;
3305 	if (!vj)
3306 		return;
3307 	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3308 	st->vj.vjs_compressed = vj->sls_o_compressed;
3309 	st->vj.vjs_searches = vj->sls_o_searches;
3310 	st->vj.vjs_misses = vj->sls_o_misses;
3311 	st->vj.vjs_errorin = vj->sls_i_error;
3312 	st->vj.vjs_tossed = vj->sls_i_tossed;
3313 	st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3314 	st->vj.vjs_compressedin = vj->sls_i_compressed;
3315 }
3316 
3317 /*
3318  * Stuff for handling the lists of ppp units and channels
3319  * and for initialization.
3320  */
3321 
3322 /*
3323  * Create a new ppp interface unit.  Fails if it can't allocate memory
3324  * or if there is already a unit with the requested number.
3325  * unit == -1 means allocate a new number.
3326  */
ppp_create_interface(struct net * net,struct file * file,int * unit)3327 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3328 {
3329 	struct ppp_config conf = {
3330 		.file = file,
3331 		.unit = *unit,
3332 		.ifname_is_set = false,
3333 	};
3334 	struct net_device *dev;
3335 	struct ppp *ppp;
3336 	int err;
3337 
3338 	dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3339 	if (!dev) {
3340 		err = -ENOMEM;
3341 		goto err;
3342 	}
3343 	dev_net_set(dev, net);
3344 	dev->rtnl_link_ops = &ppp_link_ops;
3345 
3346 	rtnl_lock();
3347 
3348 	err = ppp_dev_configure(net, dev, &conf);
3349 	if (err < 0)
3350 		goto err_dev;
3351 	ppp = netdev_priv(dev);
3352 	*unit = ppp->file.index;
3353 
3354 	rtnl_unlock();
3355 
3356 	return 0;
3357 
3358 err_dev:
3359 	rtnl_unlock();
3360 	free_netdev(dev);
3361 err:
3362 	return err;
3363 }
3364 
3365 /*
3366  * Initialize a ppp_file structure.
3367  */
3368 static void
init_ppp_file(struct ppp_file * pf,int kind)3369 init_ppp_file(struct ppp_file *pf, int kind)
3370 {
3371 	pf->kind = kind;
3372 	skb_queue_head_init(&pf->xq);
3373 	skb_queue_head_init(&pf->rq);
3374 	refcount_set(&pf->refcnt, 1);
3375 	init_waitqueue_head(&pf->rwait);
3376 }
3377 
3378 /*
3379  * Free the memory used by a ppp unit.  This is only called once
3380  * there are no channels connected to the unit and no file structs
3381  * that reference the unit.
3382  */
ppp_destroy_interface(struct ppp * ppp)3383 static void ppp_destroy_interface(struct ppp *ppp)
3384 {
3385 	atomic_dec(&ppp_unit_count);
3386 
3387 	if (!ppp->file.dead || ppp->n_channels) {
3388 		/* "can't happen" */
3389 		netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3390 			   "but dead=%d n_channels=%d !\n",
3391 			   ppp, ppp->file.dead, ppp->n_channels);
3392 		return;
3393 	}
3394 
3395 	ppp_ccp_closed(ppp);
3396 	if (ppp->vj) {
3397 		slhc_free(ppp->vj);
3398 		ppp->vj = NULL;
3399 	}
3400 	skb_queue_purge(&ppp->file.xq);
3401 	skb_queue_purge(&ppp->file.rq);
3402 #ifdef CONFIG_PPP_MULTILINK
3403 	skb_queue_purge(&ppp->mrq);
3404 #endif /* CONFIG_PPP_MULTILINK */
3405 #ifdef CONFIG_PPP_FILTER
3406 	if (ppp->pass_filter) {
3407 		bpf_prog_destroy(ppp->pass_filter);
3408 		ppp->pass_filter = NULL;
3409 	}
3410 
3411 	if (ppp->active_filter) {
3412 		bpf_prog_destroy(ppp->active_filter);
3413 		ppp->active_filter = NULL;
3414 	}
3415 #endif /* CONFIG_PPP_FILTER */
3416 
3417 	kfree_skb(ppp->xmit_pending);
3418 	free_percpu(ppp->xmit_recursion);
3419 
3420 	free_netdev(ppp->dev);
3421 }
3422 
3423 /*
3424  * Locate an existing ppp unit.
3425  * The caller should have locked the all_ppp_mutex.
3426  */
3427 static struct ppp *
ppp_find_unit(struct ppp_net * pn,int unit)3428 ppp_find_unit(struct ppp_net *pn, int unit)
3429 {
3430 	return unit_find(&pn->units_idr, unit);
3431 }
3432 
3433 /*
3434  * Locate an existing ppp channel.
3435  * The caller should have locked the all_channels_lock.
3436  * First we look in the new_channels list, then in the
3437  * all_channels list.  If found in the new_channels list,
3438  * we move it to the all_channels list.  This is for speed
3439  * when we have a lot of channels in use.
3440  */
3441 static struct channel *
ppp_find_channel(struct ppp_net * pn,int unit)3442 ppp_find_channel(struct ppp_net *pn, int unit)
3443 {
3444 	struct channel *pch;
3445 
3446 	list_for_each_entry(pch, &pn->new_channels, list) {
3447 		if (pch->file.index == unit) {
3448 			list_move(&pch->list, &pn->all_channels);
3449 			return pch;
3450 		}
3451 	}
3452 
3453 	list_for_each_entry(pch, &pn->all_channels, list) {
3454 		if (pch->file.index == unit)
3455 			return pch;
3456 	}
3457 
3458 	return NULL;
3459 }
3460 
3461 /*
3462  * Connect a PPP channel to a PPP interface unit.
3463  */
3464 static int
ppp_connect_channel(struct channel * pch,int unit)3465 ppp_connect_channel(struct channel *pch, int unit)
3466 {
3467 	struct ppp *ppp;
3468 	struct ppp_net *pn;
3469 	int ret = -ENXIO;
3470 	int hdrlen;
3471 
3472 	pn = ppp_pernet(pch->chan_net);
3473 
3474 	mutex_lock(&pn->all_ppp_mutex);
3475 	ppp = ppp_find_unit(pn, unit);
3476 	if (!ppp)
3477 		goto out;
3478 	write_lock_bh(&pch->upl);
3479 	ret = -EINVAL;
3480 	if (pch->ppp ||
3481 	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3482 		goto outl;
3483 
3484 	ppp_lock(ppp);
3485 	spin_lock_bh(&pch->downl);
3486 	if (!pch->chan) {
3487 		/* Don't connect unregistered channels */
3488 		spin_unlock_bh(&pch->downl);
3489 		ppp_unlock(ppp);
3490 		ret = -ENOTCONN;
3491 		goto outl;
3492 	}
3493 	spin_unlock_bh(&pch->downl);
3494 	if (pch->file.hdrlen > ppp->file.hdrlen)
3495 		ppp->file.hdrlen = pch->file.hdrlen;
3496 	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
3497 	if (hdrlen > ppp->dev->hard_header_len)
3498 		ppp->dev->hard_header_len = hdrlen;
3499 	list_add_tail(&pch->clist, &ppp->channels);
3500 	++ppp->n_channels;
3501 	pch->ppp = ppp;
3502 	refcount_inc(&ppp->file.refcnt);
3503 	ppp_unlock(ppp);
3504 	ret = 0;
3505 
3506  outl:
3507 	write_unlock_bh(&pch->upl);
3508  out:
3509 	mutex_unlock(&pn->all_ppp_mutex);
3510 	return ret;
3511 }
3512 
3513 /*
3514  * Disconnect a channel from its ppp unit.
3515  */
3516 static int
ppp_disconnect_channel(struct channel * pch)3517 ppp_disconnect_channel(struct channel *pch)
3518 {
3519 	struct ppp *ppp;
3520 	int err = -EINVAL;
3521 
3522 	write_lock_bh(&pch->upl);
3523 	ppp = pch->ppp;
3524 	pch->ppp = NULL;
3525 	write_unlock_bh(&pch->upl);
3526 	if (ppp) {
3527 		/* remove it from the ppp unit's list */
3528 		ppp_lock(ppp);
3529 		list_del(&pch->clist);
3530 		if (--ppp->n_channels == 0)
3531 			wake_up_interruptible(&ppp->file.rwait);
3532 		ppp_unlock(ppp);
3533 		if (refcount_dec_and_test(&ppp->file.refcnt))
3534 			ppp_destroy_interface(ppp);
3535 		err = 0;
3536 	}
3537 	return err;
3538 }
3539 
3540 /*
3541  * Free up the resources used by a ppp channel.
3542  */
ppp_destroy_channel(struct channel * pch)3543 static void ppp_destroy_channel(struct channel *pch)
3544 {
3545 	put_net_track(pch->chan_net, &pch->ns_tracker);
3546 	pch->chan_net = NULL;
3547 
3548 	atomic_dec(&channel_count);
3549 
3550 	if (!pch->file.dead) {
3551 		/* "can't happen" */
3552 		pr_err("ppp: destroying undead channel %p !\n", pch);
3553 		return;
3554 	}
3555 	skb_queue_purge(&pch->file.xq);
3556 	skb_queue_purge(&pch->file.rq);
3557 	kfree(pch);
3558 }
3559 
ppp_cleanup(void)3560 static void __exit ppp_cleanup(void)
3561 {
3562 	/* should never happen */
3563 	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3564 		pr_err("PPP: removing module but units remain!\n");
3565 	rtnl_link_unregister(&ppp_link_ops);
3566 	unregister_chrdev(PPP_MAJOR, "ppp");
3567 	device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0));
3568 	class_unregister(&ppp_class);
3569 	unregister_pernet_device(&ppp_net_ops);
3570 }
3571 
3572 /*
3573  * Units handling. Caller must protect concurrent access
3574  * by holding all_ppp_mutex
3575  */
3576 
3577 /* associate pointer with specified number */
unit_set(struct idr * p,void * ptr,int n)3578 static int unit_set(struct idr *p, void *ptr, int n)
3579 {
3580 	int unit;
3581 
3582 	unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3583 	if (unit == -ENOSPC)
3584 		unit = -EINVAL;
3585 	return unit;
3586 }
3587 
3588 /* get new free unit number and associate pointer with it */
unit_get(struct idr * p,void * ptr,int min)3589 static int unit_get(struct idr *p, void *ptr, int min)
3590 {
3591 	return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3592 }
3593 
3594 /* put unit number back to a pool */
unit_put(struct idr * p,int n)3595 static void unit_put(struct idr *p, int n)
3596 {
3597 	idr_remove(p, n);
3598 }
3599 
3600 /* get pointer associated with the number */
unit_find(struct idr * p,int n)3601 static void *unit_find(struct idr *p, int n)
3602 {
3603 	return idr_find(p, n);
3604 }
3605 
3606 /* Module/initialization stuff */
3607 
3608 module_init(ppp_init);
3609 module_exit(ppp_cleanup);
3610 
3611 EXPORT_SYMBOL(ppp_register_net_channel);
3612 EXPORT_SYMBOL(ppp_register_channel);
3613 EXPORT_SYMBOL(ppp_unregister_channel);
3614 EXPORT_SYMBOL(ppp_channel_index);
3615 EXPORT_SYMBOL(ppp_unit_number);
3616 EXPORT_SYMBOL(ppp_dev_name);
3617 EXPORT_SYMBOL(ppp_input);
3618 EXPORT_SYMBOL(ppp_input_error);
3619 EXPORT_SYMBOL(ppp_output_wakeup);
3620 EXPORT_SYMBOL(ppp_register_compressor);
3621 EXPORT_SYMBOL(ppp_unregister_compressor);
3622 MODULE_DESCRIPTION("Generic PPP layer driver");
3623 MODULE_LICENSE("GPL");
3624 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3625 MODULE_ALIAS_RTNL_LINK("ppp");
3626 MODULE_ALIAS("devname:ppp");
3627