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