xref: /openbmc/linux/drivers/net/ppp/ppp_generic.c (revision f9620e2a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Generic PPP layer for Linux.
4  *
5  * Copyright 1999-2002 Paul Mackerras.
6  *
7  * The generic PPP layer handles the PPP network interfaces, the
8  * /dev/ppp device, packet and VJ compression, and multilink.
9  * It talks to PPP `channels' via the interface defined in
10  * include/linux/ppp_channel.h.  Channels provide the basic means for
11  * sending and receiving PPP frames on some kind of communications
12  * channel.
13  *
14  * Part of the code in this driver was inspired by the old async-only
15  * PPP driver, written by Michael Callahan and Al Longyear, and
16  * subsequently hacked by Paul Mackerras.
17  *
18  * ==FILEVERSION 20041108==
19  */
20 
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/sched/signal.h>
24 #include <linux/kmod.h>
25 #include <linux/init.h>
26 #include <linux/list.h>
27 #include <linux/idr.h>
28 #include <linux/netdevice.h>
29 #include <linux/poll.h>
30 #include <linux/ppp_defs.h>
31 #include <linux/filter.h>
32 #include <linux/ppp-ioctl.h>
33 #include <linux/ppp_channel.h>
34 #include <linux/ppp-comp.h>
35 #include <linux/skbuff.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/if_arp.h>
38 #include <linux/ip.h>
39 #include <linux/tcp.h>
40 #include <linux/spinlock.h>
41 #include <linux/rwsem.h>
42 #include <linux/stddef.h>
43 #include <linux/device.h>
44 #include <linux/mutex.h>
45 #include <linux/slab.h>
46 #include <linux/file.h>
47 #include <asm/unaligned.h>
48 #include <net/slhc_vj.h>
49 #include <linux/atomic.h>
50 #include <linux/refcount.h>
51 
52 #include <linux/nsproxy.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55 
56 #define PPP_VERSION	"2.4.2"
57 
58 /*
59  * Network protocols we support.
60  */
61 #define NP_IP	0		/* Internet Protocol V4 */
62 #define NP_IPV6	1		/* Internet Protocol V6 */
63 #define NP_IPX	2		/* IPX protocol */
64 #define NP_AT	3		/* Appletalk protocol */
65 #define NP_MPLS_UC 4		/* MPLS unicast */
66 #define NP_MPLS_MC 5		/* MPLS multicast */
67 #define NUM_NP	6		/* Number of NPs. */
68 
69 #define MPHDRLEN	6	/* multilink protocol header length */
70 #define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
71 
72 #define PPP_PROTO_LEN	2
73 #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 struct class *ppp_class;
300 
301 /* per net-namespace data */
ppp_pernet(struct net * net)302 static inline struct ppp_net *ppp_pernet(struct net *net)
303 {
304 	return net_generic(net, ppp_net_id);
305 }
306 
307 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)308 static inline int proto_to_npindex(int proto)
309 {
310 	switch (proto) {
311 	case PPP_IP:
312 		return NP_IP;
313 	case PPP_IPV6:
314 		return NP_IPV6;
315 	case PPP_IPX:
316 		return NP_IPX;
317 	case PPP_AT:
318 		return NP_AT;
319 	case PPP_MPLS_UC:
320 		return NP_MPLS_UC;
321 	case PPP_MPLS_MC:
322 		return NP_MPLS_MC;
323 	}
324 	return -EINVAL;
325 }
326 
327 /* Translates an NP index into a PPP protocol number */
328 static const int npindex_to_proto[NUM_NP] = {
329 	PPP_IP,
330 	PPP_IPV6,
331 	PPP_IPX,
332 	PPP_AT,
333 	PPP_MPLS_UC,
334 	PPP_MPLS_MC,
335 };
336 
337 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)338 static inline int ethertype_to_npindex(int ethertype)
339 {
340 	switch (ethertype) {
341 	case ETH_P_IP:
342 		return NP_IP;
343 	case ETH_P_IPV6:
344 		return NP_IPV6;
345 	case ETH_P_IPX:
346 		return NP_IPX;
347 	case ETH_P_PPPTALK:
348 	case ETH_P_ATALK:
349 		return NP_AT;
350 	case ETH_P_MPLS_UC:
351 		return NP_MPLS_UC;
352 	case ETH_P_MPLS_MC:
353 		return NP_MPLS_MC;
354 	}
355 	return -1;
356 }
357 
358 /* Translates an NP index into an ethertype */
359 static const int npindex_to_ethertype[NUM_NP] = {
360 	ETH_P_IP,
361 	ETH_P_IPV6,
362 	ETH_P_IPX,
363 	ETH_P_PPPTALK,
364 	ETH_P_MPLS_UC,
365 	ETH_P_MPLS_MC,
366 };
367 
368 /*
369  * Locking shorthand.
370  */
371 #define ppp_xmit_lock(ppp)	spin_lock_bh(&(ppp)->wlock)
372 #define ppp_xmit_unlock(ppp)	spin_unlock_bh(&(ppp)->wlock)
373 #define ppp_recv_lock(ppp)	spin_lock_bh(&(ppp)->rlock)
374 #define ppp_recv_unlock(ppp)	spin_unlock_bh(&(ppp)->rlock)
375 #define ppp_lock(ppp)		do { ppp_xmit_lock(ppp); \
376 				     ppp_recv_lock(ppp); } while (0)
377 #define ppp_unlock(ppp)		do { ppp_recv_unlock(ppp); \
378 				     ppp_xmit_unlock(ppp); } while (0)
379 
380 /*
381  * /dev/ppp device routines.
382  * The /dev/ppp device is used by pppd to control the ppp unit.
383  * It supports the read, write, ioctl and poll functions.
384  * Open instances of /dev/ppp can be in one of three states:
385  * unattached, attached to a ppp unit, or attached to a ppp channel.
386  */
ppp_open(struct inode * inode,struct file * file)387 static int ppp_open(struct inode *inode, struct file *file)
388 {
389 	/*
390 	 * This could (should?) be enforced by the permissions on /dev/ppp.
391 	 */
392 	if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
393 		return -EPERM;
394 	return 0;
395 }
396 
ppp_release(struct inode * unused,struct file * file)397 static int ppp_release(struct inode *unused, struct file *file)
398 {
399 	struct ppp_file *pf = file->private_data;
400 	struct ppp *ppp;
401 
402 	if (pf) {
403 		file->private_data = NULL;
404 		if (pf->kind == INTERFACE) {
405 			ppp = PF_TO_PPP(pf);
406 			rtnl_lock();
407 			if (file == ppp->owner)
408 				unregister_netdevice(ppp->dev);
409 			rtnl_unlock();
410 		}
411 		if (refcount_dec_and_test(&pf->refcnt)) {
412 			switch (pf->kind) {
413 			case INTERFACE:
414 				ppp_destroy_interface(PF_TO_PPP(pf));
415 				break;
416 			case CHANNEL:
417 				ppp_destroy_channel(PF_TO_CHANNEL(pf));
418 				break;
419 			}
420 		}
421 	}
422 	return 0;
423 }
424 
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)425 static ssize_t ppp_read(struct file *file, char __user *buf,
426 			size_t count, loff_t *ppos)
427 {
428 	struct ppp_file *pf = file->private_data;
429 	DECLARE_WAITQUEUE(wait, current);
430 	ssize_t ret;
431 	struct sk_buff *skb = NULL;
432 	struct iovec iov;
433 	struct iov_iter to;
434 
435 	ret = count;
436 
437 	if (!pf)
438 		return -ENXIO;
439 	add_wait_queue(&pf->rwait, &wait);
440 	for (;;) {
441 		set_current_state(TASK_INTERRUPTIBLE);
442 		skb = skb_dequeue(&pf->rq);
443 		if (skb)
444 			break;
445 		ret = 0;
446 		if (pf->dead)
447 			break;
448 		if (pf->kind == INTERFACE) {
449 			/*
450 			 * Return 0 (EOF) on an interface that has no
451 			 * channels connected, unless it is looping
452 			 * network traffic (demand mode).
453 			 */
454 			struct ppp *ppp = PF_TO_PPP(pf);
455 
456 			ppp_recv_lock(ppp);
457 			if (ppp->n_channels == 0 &&
458 			    (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
459 				ppp_recv_unlock(ppp);
460 				break;
461 			}
462 			ppp_recv_unlock(ppp);
463 		}
464 		ret = -EAGAIN;
465 		if (file->f_flags & O_NONBLOCK)
466 			break;
467 		ret = -ERESTARTSYS;
468 		if (signal_pending(current))
469 			break;
470 		schedule();
471 	}
472 	set_current_state(TASK_RUNNING);
473 	remove_wait_queue(&pf->rwait, &wait);
474 
475 	if (!skb)
476 		goto out;
477 
478 	ret = -EOVERFLOW;
479 	if (skb->len > count)
480 		goto outf;
481 	ret = -EFAULT;
482 	iov.iov_base = buf;
483 	iov.iov_len = count;
484 	iov_iter_init(&to, ITER_DEST, &iov, 1, count);
485 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
486 		goto outf;
487 	ret = skb->len;
488 
489  outf:
490 	kfree_skb(skb);
491  out:
492 	return ret;
493 }
494 
ppp_check_packet(struct sk_buff * skb,size_t count)495 static bool ppp_check_packet(struct sk_buff *skb, size_t count)
496 {
497 	/* LCP packets must include LCP header which 4 bytes long:
498 	 * 1-byte code, 1-byte identifier, and 2-byte length.
499 	 */
500 	return get_unaligned_be16(skb->data) != PPP_LCP ||
501 		count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
502 }
503 
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)504 static ssize_t ppp_write(struct file *file, const char __user *buf,
505 			 size_t count, loff_t *ppos)
506 {
507 	struct ppp_file *pf = file->private_data;
508 	struct sk_buff *skb;
509 	ssize_t ret;
510 
511 	if (!pf)
512 		return -ENXIO;
513 	/* All PPP packets should start with the 2-byte protocol */
514 	if (count < PPP_PROTO_LEN)
515 		return -EINVAL;
516 	ret = -ENOMEM;
517 	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
518 	if (!skb)
519 		goto out;
520 	skb_reserve(skb, pf->hdrlen);
521 	ret = -EFAULT;
522 	if (copy_from_user(skb_put(skb, count), buf, count)) {
523 		kfree_skb(skb);
524 		goto out;
525 	}
526 	ret = -EINVAL;
527 	if (unlikely(!ppp_check_packet(skb, count))) {
528 		kfree_skb(skb);
529 		goto out;
530 	}
531 
532 	switch (pf->kind) {
533 	case INTERFACE:
534 		ppp_xmit_process(PF_TO_PPP(pf), skb);
535 		break;
536 	case CHANNEL:
537 		skb_queue_tail(&pf->xq, skb);
538 		ppp_channel_push(PF_TO_CHANNEL(pf));
539 		break;
540 	}
541 
542 	ret = count;
543 
544  out:
545 	return ret;
546 }
547 
548 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)549 static __poll_t ppp_poll(struct file *file, poll_table *wait)
550 {
551 	struct ppp_file *pf = file->private_data;
552 	__poll_t mask;
553 
554 	if (!pf)
555 		return 0;
556 	poll_wait(file, &pf->rwait, wait);
557 	mask = EPOLLOUT | EPOLLWRNORM;
558 	if (skb_peek(&pf->rq))
559 		mask |= EPOLLIN | EPOLLRDNORM;
560 	if (pf->dead)
561 		mask |= EPOLLHUP;
562 	else if (pf->kind == INTERFACE) {
563 		/* see comment in ppp_read */
564 		struct ppp *ppp = PF_TO_PPP(pf);
565 
566 		ppp_recv_lock(ppp);
567 		if (ppp->n_channels == 0 &&
568 		    (ppp->flags & SC_LOOP_TRAFFIC) == 0)
569 			mask |= EPOLLIN | EPOLLRDNORM;
570 		ppp_recv_unlock(ppp);
571 	}
572 
573 	return mask;
574 }
575 
576 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)577 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
578 {
579 	struct sock_fprog_kern fprog;
580 	struct bpf_prog *res = NULL;
581 	int err;
582 
583 	if (!uprog->len)
584 		return NULL;
585 
586 	/* uprog->len is unsigned short, so no overflow here */
587 	fprog.len = uprog->len;
588 	fprog.filter = memdup_user(uprog->filter,
589 				   uprog->len * sizeof(struct sock_filter));
590 	if (IS_ERR(fprog.filter))
591 		return ERR_CAST(fprog.filter);
592 
593 	err = bpf_prog_create(&res, &fprog);
594 	kfree(fprog.filter);
595 
596 	return err ? ERR_PTR(err) : res;
597 }
598 
ppp_get_filter(struct sock_fprog __user * p)599 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
600 {
601 	struct sock_fprog uprog;
602 
603 	if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
604 		return ERR_PTR(-EFAULT);
605 	return get_filter(&uprog);
606 }
607 
608 #ifdef CONFIG_COMPAT
609 struct sock_fprog32 {
610 	unsigned short len;
611 	compat_caddr_t filter;
612 };
613 
614 #define PPPIOCSPASS32		_IOW('t', 71, struct sock_fprog32)
615 #define PPPIOCSACTIVE32		_IOW('t', 70, struct sock_fprog32)
616 
compat_ppp_get_filter(struct sock_fprog32 __user * p)617 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
618 {
619 	struct sock_fprog32 uprog32;
620 	struct sock_fprog uprog;
621 
622 	if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
623 		return ERR_PTR(-EFAULT);
624 	uprog.len = uprog32.len;
625 	uprog.filter = compat_ptr(uprog32.filter);
626 	return get_filter(&uprog);
627 }
628 #endif
629 #endif
630 
631 /* Bridge one PPP channel to another.
632  * When two channels are bridged, ppp_input on one channel is redirected to
633  * the other's ops->start_xmit handler.
634  * In order to safely bridge channels we must reject channels which are already
635  * part of a bridge instance, or which form part of an existing unit.
636  * Once successfully bridged, each channel holds a reference on the other
637  * to prevent it being freed while the bridge is extant.
638  */
ppp_bridge_channels(struct channel * pch,struct channel * pchb)639 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
640 {
641 	write_lock_bh(&pch->upl);
642 	if (pch->ppp ||
643 	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
644 		write_unlock_bh(&pch->upl);
645 		return -EALREADY;
646 	}
647 	refcount_inc(&pchb->file.refcnt);
648 	rcu_assign_pointer(pch->bridge, pchb);
649 	write_unlock_bh(&pch->upl);
650 
651 	write_lock_bh(&pchb->upl);
652 	if (pchb->ppp ||
653 	    rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
654 		write_unlock_bh(&pchb->upl);
655 		goto err_unset;
656 	}
657 	refcount_inc(&pch->file.refcnt);
658 	rcu_assign_pointer(pchb->bridge, pch);
659 	write_unlock_bh(&pchb->upl);
660 
661 	return 0;
662 
663 err_unset:
664 	write_lock_bh(&pch->upl);
665 	/* Re-read pch->bridge with upl held in case it was modified concurrently */
666 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
667 	RCU_INIT_POINTER(pch->bridge, NULL);
668 	write_unlock_bh(&pch->upl);
669 	synchronize_rcu();
670 
671 	if (pchb)
672 		if (refcount_dec_and_test(&pchb->file.refcnt))
673 			ppp_destroy_channel(pchb);
674 
675 	return -EALREADY;
676 }
677 
ppp_unbridge_channels(struct channel * pch)678 static int ppp_unbridge_channels(struct channel *pch)
679 {
680 	struct channel *pchb, *pchbb;
681 
682 	write_lock_bh(&pch->upl);
683 	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
684 	if (!pchb) {
685 		write_unlock_bh(&pch->upl);
686 		return -EINVAL;
687 	}
688 	RCU_INIT_POINTER(pch->bridge, NULL);
689 	write_unlock_bh(&pch->upl);
690 
691 	/* Only modify pchb if phcb->bridge points back to pch.
692 	 * If not, it implies that there has been a race unbridging (and possibly
693 	 * even rebridging) pchb.  We should leave pchb alone to avoid either a
694 	 * refcount underflow, or breaking another established bridge instance.
695 	 */
696 	write_lock_bh(&pchb->upl);
697 	pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
698 	if (pchbb == pch)
699 		RCU_INIT_POINTER(pchb->bridge, NULL);
700 	write_unlock_bh(&pchb->upl);
701 
702 	synchronize_rcu();
703 
704 	if (pchbb == pch)
705 		if (refcount_dec_and_test(&pch->file.refcnt))
706 			ppp_destroy_channel(pch);
707 
708 	if (refcount_dec_and_test(&pchb->file.refcnt))
709 		ppp_destroy_channel(pchb);
710 
711 	return 0;
712 }
713 
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)714 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
715 {
716 	struct ppp_file *pf;
717 	struct ppp *ppp;
718 	int err = -EFAULT, val, val2, i;
719 	struct ppp_idle32 idle32;
720 	struct ppp_idle64 idle64;
721 	struct npioctl npi;
722 	int unit, cflags;
723 	struct slcompress *vj;
724 	void __user *argp = (void __user *)arg;
725 	int __user *p = argp;
726 
727 	mutex_lock(&ppp_mutex);
728 
729 	pf = file->private_data;
730 	if (!pf) {
731 		err = ppp_unattached_ioctl(current->nsproxy->net_ns,
732 					   pf, file, cmd, arg);
733 		goto out;
734 	}
735 
736 	if (cmd == PPPIOCDETACH) {
737 		/*
738 		 * PPPIOCDETACH is no longer supported as it was heavily broken,
739 		 * and is only known to have been used by pppd older than
740 		 * ppp-2.4.2 (released November 2003).
741 		 */
742 		pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
743 			     current->comm, current->pid);
744 		err = -EINVAL;
745 		goto out;
746 	}
747 
748 	if (pf->kind == CHANNEL) {
749 		struct channel *pch, *pchb;
750 		struct ppp_channel *chan;
751 		struct ppp_net *pn;
752 
753 		pch = PF_TO_CHANNEL(pf);
754 
755 		switch (cmd) {
756 		case PPPIOCCONNECT:
757 			if (get_user(unit, p))
758 				break;
759 			err = ppp_connect_channel(pch, unit);
760 			break;
761 
762 		case PPPIOCDISCONN:
763 			err = ppp_disconnect_channel(pch);
764 			break;
765 
766 		case PPPIOCBRIDGECHAN:
767 			if (get_user(unit, p))
768 				break;
769 			err = -ENXIO;
770 			pn = ppp_pernet(current->nsproxy->net_ns);
771 			spin_lock_bh(&pn->all_channels_lock);
772 			pchb = ppp_find_channel(pn, unit);
773 			/* Hold a reference to prevent pchb being freed while
774 			 * we establish the bridge.
775 			 */
776 			if (pchb)
777 				refcount_inc(&pchb->file.refcnt);
778 			spin_unlock_bh(&pn->all_channels_lock);
779 			if (!pchb)
780 				break;
781 			err = ppp_bridge_channels(pch, pchb);
782 			/* Drop earlier refcount now bridge establishment is complete */
783 			if (refcount_dec_and_test(&pchb->file.refcnt))
784 				ppp_destroy_channel(pchb);
785 			break;
786 
787 		case PPPIOCUNBRIDGECHAN:
788 			err = ppp_unbridge_channels(pch);
789 			break;
790 
791 		default:
792 			down_read(&pch->chan_sem);
793 			chan = pch->chan;
794 			err = -ENOTTY;
795 			if (chan && chan->ops->ioctl)
796 				err = chan->ops->ioctl(chan, cmd, arg);
797 			up_read(&pch->chan_sem);
798 		}
799 		goto out;
800 	}
801 
802 	if (pf->kind != INTERFACE) {
803 		/* can't happen */
804 		pr_err("PPP: not interface or channel??\n");
805 		err = -EINVAL;
806 		goto out;
807 	}
808 
809 	ppp = PF_TO_PPP(pf);
810 	switch (cmd) {
811 	case PPPIOCSMRU:
812 		if (get_user(val, p))
813 			break;
814 		ppp->mru = val;
815 		err = 0;
816 		break;
817 
818 	case PPPIOCSFLAGS:
819 		if (get_user(val, p))
820 			break;
821 		ppp_lock(ppp);
822 		cflags = ppp->flags & ~val;
823 #ifdef CONFIG_PPP_MULTILINK
824 		if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
825 			ppp->nextseq = 0;
826 #endif
827 		ppp->flags = val & SC_FLAG_BITS;
828 		ppp_unlock(ppp);
829 		if (cflags & SC_CCP_OPEN)
830 			ppp_ccp_closed(ppp);
831 		err = 0;
832 		break;
833 
834 	case PPPIOCGFLAGS:
835 		val = ppp->flags | ppp->xstate | ppp->rstate;
836 		if (put_user(val, p))
837 			break;
838 		err = 0;
839 		break;
840 
841 	case PPPIOCSCOMPRESS:
842 	{
843 		struct ppp_option_data data;
844 		if (copy_from_user(&data, argp, sizeof(data)))
845 			err = -EFAULT;
846 		else
847 			err = ppp_set_compress(ppp, &data);
848 		break;
849 	}
850 	case PPPIOCGUNIT:
851 		if (put_user(ppp->file.index, p))
852 			break;
853 		err = 0;
854 		break;
855 
856 	case PPPIOCSDEBUG:
857 		if (get_user(val, p))
858 			break;
859 		ppp->debug = val;
860 		err = 0;
861 		break;
862 
863 	case PPPIOCGDEBUG:
864 		if (put_user(ppp->debug, p))
865 			break;
866 		err = 0;
867 		break;
868 
869 	case PPPIOCGIDLE32:
870                 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
871                 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
872                 if (copy_to_user(argp, &idle32, sizeof(idle32)))
873 			break;
874 		err = 0;
875 		break;
876 
877 	case PPPIOCGIDLE64:
878 		idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
879 		idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
880 		if (copy_to_user(argp, &idle64, sizeof(idle64)))
881 			break;
882 		err = 0;
883 		break;
884 
885 	case PPPIOCSMAXCID:
886 		if (get_user(val, p))
887 			break;
888 		val2 = 15;
889 		if ((val >> 16) != 0) {
890 			val2 = val >> 16;
891 			val &= 0xffff;
892 		}
893 		vj = slhc_init(val2+1, val+1);
894 		if (IS_ERR(vj)) {
895 			err = PTR_ERR(vj);
896 			break;
897 		}
898 		ppp_lock(ppp);
899 		if (ppp->vj)
900 			slhc_free(ppp->vj);
901 		ppp->vj = vj;
902 		ppp_unlock(ppp);
903 		err = 0;
904 		break;
905 
906 	case PPPIOCGNPMODE:
907 	case PPPIOCSNPMODE:
908 		if (copy_from_user(&npi, argp, sizeof(npi)))
909 			break;
910 		err = proto_to_npindex(npi.protocol);
911 		if (err < 0)
912 			break;
913 		i = err;
914 		if (cmd == PPPIOCGNPMODE) {
915 			err = -EFAULT;
916 			npi.mode = ppp->npmode[i];
917 			if (copy_to_user(argp, &npi, sizeof(npi)))
918 				break;
919 		} else {
920 			ppp->npmode[i] = npi.mode;
921 			/* we may be able to transmit more packets now (??) */
922 			netif_wake_queue(ppp->dev);
923 		}
924 		err = 0;
925 		break;
926 
927 #ifdef CONFIG_PPP_FILTER
928 	case PPPIOCSPASS:
929 	case PPPIOCSACTIVE:
930 	{
931 		struct bpf_prog *filter = ppp_get_filter(argp);
932 		struct bpf_prog **which;
933 
934 		if (IS_ERR(filter)) {
935 			err = PTR_ERR(filter);
936 			break;
937 		}
938 		if (cmd == PPPIOCSPASS)
939 			which = &ppp->pass_filter;
940 		else
941 			which = &ppp->active_filter;
942 		ppp_lock(ppp);
943 		if (*which)
944 			bpf_prog_destroy(*which);
945 		*which = filter;
946 		ppp_unlock(ppp);
947 		err = 0;
948 		break;
949 	}
950 #endif /* CONFIG_PPP_FILTER */
951 
952 #ifdef CONFIG_PPP_MULTILINK
953 	case PPPIOCSMRRU:
954 		if (get_user(val, p))
955 			break;
956 		ppp_recv_lock(ppp);
957 		ppp->mrru = val;
958 		ppp_recv_unlock(ppp);
959 		err = 0;
960 		break;
961 #endif /* CONFIG_PPP_MULTILINK */
962 
963 	default:
964 		err = -ENOTTY;
965 	}
966 
967 out:
968 	mutex_unlock(&ppp_mutex);
969 
970 	return err;
971 }
972 
973 #ifdef CONFIG_COMPAT
974 struct ppp_option_data32 {
975 	compat_uptr_t		ptr;
976 	u32			length;
977 	compat_int_t		transmit;
978 };
979 #define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)
980 
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)981 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
982 {
983 	struct ppp_file *pf;
984 	int err = -ENOIOCTLCMD;
985 	void __user *argp = (void __user *)arg;
986 
987 	mutex_lock(&ppp_mutex);
988 
989 	pf = file->private_data;
990 	if (pf && pf->kind == INTERFACE) {
991 		struct ppp *ppp = PF_TO_PPP(pf);
992 		switch (cmd) {
993 #ifdef CONFIG_PPP_FILTER
994 		case PPPIOCSPASS32:
995 		case PPPIOCSACTIVE32:
996 		{
997 			struct bpf_prog *filter = compat_ppp_get_filter(argp);
998 			struct bpf_prog **which;
999 
1000 			if (IS_ERR(filter)) {
1001 				err = PTR_ERR(filter);
1002 				break;
1003 			}
1004 			if (cmd == PPPIOCSPASS32)
1005 				which = &ppp->pass_filter;
1006 			else
1007 				which = &ppp->active_filter;
1008 			ppp_lock(ppp);
1009 			if (*which)
1010 				bpf_prog_destroy(*which);
1011 			*which = filter;
1012 			ppp_unlock(ppp);
1013 			err = 0;
1014 			break;
1015 		}
1016 #endif /* CONFIG_PPP_FILTER */
1017 		case PPPIOCSCOMPRESS32:
1018 		{
1019 			struct ppp_option_data32 data32;
1020 			if (copy_from_user(&data32, argp, sizeof(data32))) {
1021 				err = -EFAULT;
1022 			} else {
1023 				struct ppp_option_data data = {
1024 					.ptr = compat_ptr(data32.ptr),
1025 					.length = data32.length,
1026 					.transmit = data32.transmit
1027 				};
1028 				err = ppp_set_compress(ppp, &data);
1029 			}
1030 			break;
1031 		}
1032 		}
1033 	}
1034 	mutex_unlock(&ppp_mutex);
1035 
1036 	/* all other commands have compatible arguments */
1037 	if (err == -ENOIOCTLCMD)
1038 		err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1039 
1040 	return err;
1041 }
1042 #endif
1043 
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)1044 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1045 			struct file *file, unsigned int cmd, unsigned long arg)
1046 {
1047 	int unit, err = -EFAULT;
1048 	struct ppp *ppp;
1049 	struct channel *chan;
1050 	struct ppp_net *pn;
1051 	int __user *p = (int __user *)arg;
1052 
1053 	switch (cmd) {
1054 	case PPPIOCNEWUNIT:
1055 		/* Create a new ppp unit */
1056 		if (get_user(unit, p))
1057 			break;
1058 		err = ppp_create_interface(net, file, &unit);
1059 		if (err < 0)
1060 			break;
1061 
1062 		err = -EFAULT;
1063 		if (put_user(unit, p))
1064 			break;
1065 		err = 0;
1066 		break;
1067 
1068 	case PPPIOCATTACH:
1069 		/* Attach to an existing ppp unit */
1070 		if (get_user(unit, p))
1071 			break;
1072 		err = -ENXIO;
1073 		pn = ppp_pernet(net);
1074 		mutex_lock(&pn->all_ppp_mutex);
1075 		ppp = ppp_find_unit(pn, unit);
1076 		if (ppp) {
1077 			refcount_inc(&ppp->file.refcnt);
1078 			file->private_data = &ppp->file;
1079 			err = 0;
1080 		}
1081 		mutex_unlock(&pn->all_ppp_mutex);
1082 		break;
1083 
1084 	case PPPIOCATTCHAN:
1085 		if (get_user(unit, p))
1086 			break;
1087 		err = -ENXIO;
1088 		pn = ppp_pernet(net);
1089 		spin_lock_bh(&pn->all_channels_lock);
1090 		chan = ppp_find_channel(pn, unit);
1091 		if (chan) {
1092 			refcount_inc(&chan->file.refcnt);
1093 			file->private_data = &chan->file;
1094 			err = 0;
1095 		}
1096 		spin_unlock_bh(&pn->all_channels_lock);
1097 		break;
1098 
1099 	default:
1100 		err = -ENOTTY;
1101 	}
1102 
1103 	return err;
1104 }
1105 
1106 static const struct file_operations ppp_device_fops = {
1107 	.owner		= THIS_MODULE,
1108 	.read		= ppp_read,
1109 	.write		= ppp_write,
1110 	.poll		= ppp_poll,
1111 	.unlocked_ioctl	= ppp_ioctl,
1112 #ifdef CONFIG_COMPAT
1113 	.compat_ioctl	= ppp_compat_ioctl,
1114 #endif
1115 	.open		= ppp_open,
1116 	.release	= ppp_release,
1117 	.llseek		= noop_llseek,
1118 };
1119 
ppp_init_net(struct net * net)1120 static __net_init int ppp_init_net(struct net *net)
1121 {
1122 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1123 
1124 	idr_init(&pn->units_idr);
1125 	mutex_init(&pn->all_ppp_mutex);
1126 
1127 	INIT_LIST_HEAD(&pn->all_channels);
1128 	INIT_LIST_HEAD(&pn->new_channels);
1129 
1130 	spin_lock_init(&pn->all_channels_lock);
1131 
1132 	return 0;
1133 }
1134 
ppp_exit_net(struct net * net)1135 static __net_exit void ppp_exit_net(struct net *net)
1136 {
1137 	struct ppp_net *pn = net_generic(net, ppp_net_id);
1138 	struct net_device *dev;
1139 	struct net_device *aux;
1140 	struct ppp *ppp;
1141 	LIST_HEAD(list);
1142 	int id;
1143 
1144 	rtnl_lock();
1145 	for_each_netdev_safe(net, dev, aux) {
1146 		if (dev->netdev_ops == &ppp_netdev_ops)
1147 			unregister_netdevice_queue(dev, &list);
1148 	}
1149 
1150 	idr_for_each_entry(&pn->units_idr, ppp, id)
1151 		/* Skip devices already unregistered by previous loop */
1152 		if (!net_eq(dev_net(ppp->dev), net))
1153 			unregister_netdevice_queue(ppp->dev, &list);
1154 
1155 	unregister_netdevice_many(&list);
1156 	rtnl_unlock();
1157 
1158 	mutex_destroy(&pn->all_ppp_mutex);
1159 	idr_destroy(&pn->units_idr);
1160 	WARN_ON_ONCE(!list_empty(&pn->all_channels));
1161 	WARN_ON_ONCE(!list_empty(&pn->new_channels));
1162 }
1163 
1164 static struct pernet_operations ppp_net_ops = {
1165 	.init = ppp_init_net,
1166 	.exit = ppp_exit_net,
1167 	.id   = &ppp_net_id,
1168 	.size = sizeof(struct ppp_net),
1169 };
1170 
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1171 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1172 {
1173 	struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1174 	int ret;
1175 
1176 	mutex_lock(&pn->all_ppp_mutex);
1177 
1178 	if (unit < 0) {
1179 		ret = unit_get(&pn->units_idr, ppp, 0);
1180 		if (ret < 0)
1181 			goto err;
1182 		if (!ifname_is_set) {
1183 			while (1) {
1184 				snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1185 				if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1186 					break;
1187 				unit_put(&pn->units_idr, ret);
1188 				ret = unit_get(&pn->units_idr, ppp, ret + 1);
1189 				if (ret < 0)
1190 					goto err;
1191 			}
1192 		}
1193 	} else {
1194 		/* Caller asked for a specific unit number. Fail with -EEXIST
1195 		 * if unavailable. For backward compatibility, return -EEXIST
1196 		 * too if idr allocation fails; this makes pppd retry without
1197 		 * requesting a specific unit number.
1198 		 */
1199 		if (unit_find(&pn->units_idr, unit)) {
1200 			ret = -EEXIST;
1201 			goto err;
1202 		}
1203 		ret = unit_set(&pn->units_idr, ppp, unit);
1204 		if (ret < 0) {
1205 			/* Rewrite error for backward compatibility */
1206 			ret = -EEXIST;
1207 			goto err;
1208 		}
1209 	}
1210 	ppp->file.index = ret;
1211 
1212 	if (!ifname_is_set)
1213 		snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1214 
1215 	mutex_unlock(&pn->all_ppp_mutex);
1216 
1217 	ret = register_netdevice(ppp->dev);
1218 	if (ret < 0)
1219 		goto err_unit;
1220 
1221 	atomic_inc(&ppp_unit_count);
1222 
1223 	return 0;
1224 
1225 err_unit:
1226 	mutex_lock(&pn->all_ppp_mutex);
1227 	unit_put(&pn->units_idr, ppp->file.index);
1228 err:
1229 	mutex_unlock(&pn->all_ppp_mutex);
1230 
1231 	return ret;
1232 }
1233 
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1234 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1235 			     const struct ppp_config *conf)
1236 {
1237 	struct ppp *ppp = netdev_priv(dev);
1238 	int indx;
1239 	int err;
1240 	int cpu;
1241 
1242 	ppp->dev = dev;
1243 	ppp->ppp_net = src_net;
1244 	ppp->mru = PPP_MRU;
1245 	ppp->owner = conf->file;
1246 
1247 	init_ppp_file(&ppp->file, INTERFACE);
1248 	ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1249 
1250 	for (indx = 0; indx < NUM_NP; ++indx)
1251 		ppp->npmode[indx] = NPMODE_PASS;
1252 	INIT_LIST_HEAD(&ppp->channels);
1253 	spin_lock_init(&ppp->rlock);
1254 	spin_lock_init(&ppp->wlock);
1255 
1256 	ppp->xmit_recursion = alloc_percpu(int);
1257 	if (!ppp->xmit_recursion) {
1258 		err = -ENOMEM;
1259 		goto err1;
1260 	}
1261 	for_each_possible_cpu(cpu)
1262 		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1263 
1264 #ifdef CONFIG_PPP_MULTILINK
1265 	ppp->minseq = -1;
1266 	skb_queue_head_init(&ppp->mrq);
1267 #endif /* CONFIG_PPP_MULTILINK */
1268 #ifdef CONFIG_PPP_FILTER
1269 	ppp->pass_filter = NULL;
1270 	ppp->active_filter = NULL;
1271 #endif /* CONFIG_PPP_FILTER */
1272 
1273 	err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1274 	if (err < 0)
1275 		goto err2;
1276 
1277 	conf->file->private_data = &ppp->file;
1278 
1279 	return 0;
1280 err2:
1281 	free_percpu(ppp->xmit_recursion);
1282 err1:
1283 	return err;
1284 }
1285 
1286 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1287 	[IFLA_PPP_DEV_FD]	= { .type = NLA_S32 },
1288 };
1289 
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1290 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1291 			   struct netlink_ext_ack *extack)
1292 {
1293 	if (!data)
1294 		return -EINVAL;
1295 
1296 	if (!data[IFLA_PPP_DEV_FD])
1297 		return -EINVAL;
1298 	if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1299 		return -EBADF;
1300 
1301 	return 0;
1302 }
1303 
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1304 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1305 			  struct nlattr *tb[], struct nlattr *data[],
1306 			  struct netlink_ext_ack *extack)
1307 {
1308 	struct ppp_config conf = {
1309 		.unit = -1,
1310 		.ifname_is_set = true,
1311 	};
1312 	struct file *file;
1313 	int err;
1314 
1315 	file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1316 	if (!file)
1317 		return -EBADF;
1318 
1319 	/* rtnl_lock is already held here, but ppp_create_interface() locks
1320 	 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1321 	 * possible deadlock due to lock order inversion, at the cost of
1322 	 * pushing the problem back to userspace.
1323 	 */
1324 	if (!mutex_trylock(&ppp_mutex)) {
1325 		err = -EBUSY;
1326 		goto out;
1327 	}
1328 
1329 	if (file->f_op != &ppp_device_fops || file->private_data) {
1330 		err = -EBADF;
1331 		goto out_unlock;
1332 	}
1333 
1334 	conf.file = file;
1335 
1336 	/* Don't use device name generated by the rtnetlink layer when ifname
1337 	 * isn't specified. Let ppp_dev_configure() set the device name using
1338 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1339 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1340 	 */
1341 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1342 		conf.ifname_is_set = false;
1343 
1344 	err = ppp_dev_configure(src_net, dev, &conf);
1345 
1346 out_unlock:
1347 	mutex_unlock(&ppp_mutex);
1348 out:
1349 	fput(file);
1350 
1351 	return err;
1352 }
1353 
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1354 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1355 {
1356 	unregister_netdevice_queue(dev, head);
1357 }
1358 
ppp_nl_get_size(const struct net_device * dev)1359 static size_t ppp_nl_get_size(const struct net_device *dev)
1360 {
1361 	return 0;
1362 }
1363 
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1364 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1365 {
1366 	return 0;
1367 }
1368 
ppp_nl_get_link_net(const struct net_device * dev)1369 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1370 {
1371 	struct ppp *ppp = netdev_priv(dev);
1372 
1373 	return ppp->ppp_net;
1374 }
1375 
1376 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1377 	.kind		= "ppp",
1378 	.maxtype	= IFLA_PPP_MAX,
1379 	.policy		= ppp_nl_policy,
1380 	.priv_size	= sizeof(struct ppp),
1381 	.setup		= ppp_setup,
1382 	.validate	= ppp_nl_validate,
1383 	.newlink	= ppp_nl_newlink,
1384 	.dellink	= ppp_nl_dellink,
1385 	.get_size	= ppp_nl_get_size,
1386 	.fill_info	= ppp_nl_fill_info,
1387 	.get_link_net	= ppp_nl_get_link_net,
1388 };
1389 
1390 #define PPP_MAJOR	108
1391 
1392 /* Called at boot time if ppp is compiled into the kernel,
1393    or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1394 static int __init ppp_init(void)
1395 {
1396 	int err;
1397 
1398 	pr_info("PPP generic driver version " PPP_VERSION "\n");
1399 
1400 	err = register_pernet_device(&ppp_net_ops);
1401 	if (err) {
1402 		pr_err("failed to register PPP pernet device (%d)\n", err);
1403 		goto out;
1404 	}
1405 
1406 	err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1407 	if (err) {
1408 		pr_err("failed to register PPP device (%d)\n", err);
1409 		goto out_net;
1410 	}
1411 
1412 	ppp_class = class_create("ppp");
1413 	if (IS_ERR(ppp_class)) {
1414 		err = PTR_ERR(ppp_class);
1415 		goto out_chrdev;
1416 	}
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_destroy(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 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->features |= NETIF_F_LLTX;
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_destroy(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_LICENSE("GPL");
3623 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3624 MODULE_ALIAS_RTNL_LINK("ppp");
3625 MODULE_ALIAS("devname:ppp");
3626