1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Generic PPP layer for Linux.
4 *
5 * Copyright 1999-2002 Paul Mackerras.
6 *
7 * The generic PPP layer handles the PPP network interfaces, the
8 * /dev/ppp device, packet and VJ compression, and multilink.
9 * It talks to PPP `channels' via the interface defined in
10 * include/linux/ppp_channel.h. Channels provide the basic means for
11 * sending and receiving PPP frames on some kind of communications
12 * channel.
13 *
14 * Part of the code in this driver was inspired by the old async-only
15 * PPP driver, written by Michael Callahan and Al Longyear, and
16 * subsequently hacked by Paul Mackerras.
17 *
18 * ==FILEVERSION 20041108==
19 */
20
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/sched/signal.h>
24 #include <linux/kmod.h>
25 #include <linux/init.h>
26 #include <linux/list.h>
27 #include <linux/idr.h>
28 #include <linux/netdevice.h>
29 #include <linux/poll.h>
30 #include <linux/ppp_defs.h>
31 #include <linux/filter.h>
32 #include <linux/ppp-ioctl.h>
33 #include <linux/ppp_channel.h>
34 #include <linux/ppp-comp.h>
35 #include <linux/skbuff.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/if_arp.h>
38 #include <linux/ip.h>
39 #include <linux/tcp.h>
40 #include <linux/spinlock.h>
41 #include <linux/rwsem.h>
42 #include <linux/stddef.h>
43 #include <linux/device.h>
44 #include <linux/mutex.h>
45 #include <linux/slab.h>
46 #include <linux/file.h>
47 #include <asm/unaligned.h>
48 #include <net/slhc_vj.h>
49 #include <linux/atomic.h>
50 #include <linux/refcount.h>
51
52 #include <linux/nsproxy.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55
56 #define PPP_VERSION "2.4.2"
57
58 /*
59 * Network protocols we support.
60 */
61 #define NP_IP 0 /* Internet Protocol V4 */
62 #define NP_IPV6 1 /* Internet Protocol V6 */
63 #define NP_IPX 2 /* IPX protocol */
64 #define NP_AT 3 /* Appletalk protocol */
65 #define NP_MPLS_UC 4 /* MPLS unicast */
66 #define NP_MPLS_MC 5 /* MPLS multicast */
67 #define NUM_NP 6 /* Number of NPs. */
68
69 #define MPHDRLEN 6 /* multilink protocol header length */
70 #define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
71
72 #define PPP_PROTO_LEN 2
73
74 /*
75 * An instance of /dev/ppp can be associated with either a ppp
76 * interface unit or a ppp channel. In both cases, file->private_data
77 * points to one of these.
78 */
79 struct ppp_file {
80 enum {
81 INTERFACE=1, CHANNEL
82 } kind;
83 struct sk_buff_head xq; /* pppd transmit queue */
84 struct sk_buff_head rq; /* receive queue for pppd */
85 wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
86 refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
87 int hdrlen; /* space to leave for headers */
88 int index; /* interface unit / channel number */
89 int dead; /* unit/channel has been shut down */
90 };
91
92 #define PF_TO_X(pf, X) container_of(pf, X, file)
93
94 #define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
95 #define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
96
97 /*
98 * Data structure to hold primary network stats for which
99 * we want to use 64 bit storage. Other network stats
100 * are stored in dev->stats of the ppp strucute.
101 */
102 struct ppp_link_stats {
103 u64 rx_packets;
104 u64 tx_packets;
105 u64 rx_bytes;
106 u64 tx_bytes;
107 };
108
109 /*
110 * Data structure describing one ppp unit.
111 * A ppp unit corresponds to a ppp network interface device
112 * and represents a multilink bundle.
113 * It can have 0 or more ppp channels connected to it.
114 */
115 struct ppp {
116 struct ppp_file file; /* stuff for read/write/poll 0 */
117 struct file *owner; /* file that owns this unit 48 */
118 struct list_head channels; /* list of attached channels 4c */
119 int n_channels; /* how many channels are attached 54 */
120 spinlock_t rlock; /* lock for receive side 58 */
121 spinlock_t wlock; /* lock for transmit side 5c */
122 int __percpu *xmit_recursion; /* xmit recursion detect */
123 int mru; /* max receive unit 60 */
124 unsigned int flags; /* control bits 64 */
125 unsigned int xstate; /* transmit state bits 68 */
126 unsigned int rstate; /* receive state bits 6c */
127 int debug; /* debug flags 70 */
128 struct slcompress *vj; /* state for VJ header compression */
129 enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
130 struct sk_buff *xmit_pending; /* a packet ready to go out 88 */
131 struct compressor *xcomp; /* transmit packet compressor 8c */
132 void *xc_state; /* its internal state 90 */
133 struct compressor *rcomp; /* receive decompressor 94 */
134 void *rc_state; /* its internal state 98 */
135 unsigned long last_xmit; /* jiffies when last pkt sent 9c */
136 unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
137 struct net_device *dev; /* network interface device a4 */
138 int closing; /* is device closing down? a8 */
139 #ifdef CONFIG_PPP_MULTILINK
140 int nxchan; /* next channel to send something on */
141 u32 nxseq; /* next sequence number to send */
142 int mrru; /* MP: max reconst. receive unit */
143 u32 nextseq; /* MP: seq no of next packet */
144 u32 minseq; /* MP: min of most recent seqnos */
145 struct sk_buff_head mrq; /* MP: receive reconstruction queue */
146 #endif /* CONFIG_PPP_MULTILINK */
147 #ifdef CONFIG_PPP_FILTER
148 struct bpf_prog *pass_filter; /* filter for packets to pass */
149 struct bpf_prog *active_filter; /* filter for pkts to reset idle */
150 #endif /* CONFIG_PPP_FILTER */
151 struct net *ppp_net; /* the net we belong to */
152 struct ppp_link_stats stats64; /* 64 bit network stats */
153 };
154
155 /*
156 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
157 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
158 * SC_MUST_COMP
159 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
160 * Bits in xstate: SC_COMP_RUN
161 */
162 #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
163 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
164 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
165
166 /*
167 * Private data structure for each channel.
168 * This includes the data structure used for multilink.
169 */
170 struct channel {
171 struct ppp_file file; /* stuff for read/write/poll */
172 struct list_head list; /* link in all/new_channels list */
173 struct ppp_channel *chan; /* public channel data structure */
174 struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */
175 spinlock_t downl; /* protects `chan', file.xq dequeue */
176 struct ppp *ppp; /* ppp unit we're connected to */
177 struct net *chan_net; /* the net channel belongs to */
178 netns_tracker ns_tracker;
179 struct list_head clist; /* link in list of channels per unit */
180 rwlock_t upl; /* protects `ppp' and 'bridge' */
181 struct channel __rcu *bridge; /* "bridged" ppp channel */
182 #ifdef CONFIG_PPP_MULTILINK
183 u8 avail; /* flag used in multilink stuff */
184 u8 had_frag; /* >= 1 fragments have been sent */
185 u32 lastseq; /* MP: last sequence # received */
186 int speed; /* speed of the corresponding ppp channel*/
187 #endif /* CONFIG_PPP_MULTILINK */
188 };
189
190 struct ppp_config {
191 struct file *file;
192 s32 unit;
193 bool ifname_is_set;
194 };
195
196 /*
197 * SMP locking issues:
198 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
199 * list and the ppp.n_channels field, you need to take both locks
200 * before you modify them.
201 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
202 * channel.downl.
203 */
204
205 static DEFINE_MUTEX(ppp_mutex);
206 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
207 static atomic_t channel_count = ATOMIC_INIT(0);
208
209 /* per-net private data for this module */
210 static unsigned int ppp_net_id __read_mostly;
211 struct ppp_net {
212 /* units to ppp mapping */
213 struct idr units_idr;
214
215 /*
216 * all_ppp_mutex protects the units_idr mapping.
217 * It also ensures that finding a ppp unit in the units_idr
218 * map and updating its file.refcnt field is atomic.
219 */
220 struct mutex all_ppp_mutex;
221
222 /* channels */
223 struct list_head all_channels;
224 struct list_head new_channels;
225 int last_channel_index;
226
227 /*
228 * all_channels_lock protects all_channels and
229 * last_channel_index, and the atomicity of find
230 * a channel and updating its file.refcnt field.
231 */
232 spinlock_t all_channels_lock;
233 };
234
235 /* Get the PPP protocol number from a skb */
236 #define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
237
238 /* We limit the length of ppp->file.rq to this (arbitrary) value */
239 #define PPP_MAX_RQLEN 32
240
241 /*
242 * Maximum number of multilink fragments queued up.
243 * This has to be large enough to cope with the maximum latency of
244 * the slowest channel relative to the others. Strictly it should
245 * depend on the number of channels and their characteristics.
246 */
247 #define PPP_MP_MAX_QLEN 128
248
249 /* Multilink header bits. */
250 #define B 0x80 /* this fragment begins a packet */
251 #define E 0x40 /* this fragment ends a packet */
252
253 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
254 #define seq_before(a, b) ((s32)((a) - (b)) < 0)
255 #define seq_after(a, b) ((s32)((a) - (b)) > 0)
256
257 /* Prototypes. */
258 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
259 struct file *file, unsigned int cmd, unsigned long arg);
260 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
261 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
262 static void ppp_push(struct ppp *ppp);
263 static void ppp_channel_push(struct channel *pch);
264 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
265 struct channel *pch);
266 static void ppp_receive_error(struct ppp *ppp);
267 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
268 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
269 struct sk_buff *skb);
270 #ifdef CONFIG_PPP_MULTILINK
271 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
272 struct channel *pch);
273 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
274 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
275 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
276 #endif /* CONFIG_PPP_MULTILINK */
277 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
278 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
279 static void ppp_ccp_closed(struct ppp *ppp);
280 static struct compressor *find_compressor(int type);
281 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
282 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
283 static void init_ppp_file(struct ppp_file *pf, int kind);
284 static void ppp_destroy_interface(struct ppp *ppp);
285 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
286 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
287 static int ppp_connect_channel(struct channel *pch, int unit);
288 static int ppp_disconnect_channel(struct channel *pch);
289 static void ppp_destroy_channel(struct channel *pch);
290 static int unit_get(struct idr *p, void *ptr, int min);
291 static int unit_set(struct idr *p, void *ptr, int n);
292 static void unit_put(struct idr *p, int n);
293 static void *unit_find(struct idr *p, int n);
294 static void ppp_setup(struct net_device *dev);
295
296 static const struct net_device_ops ppp_netdev_ops;
297
298 static struct class *ppp_class;
299
300 /* per net-namespace data */
ppp_pernet(struct net * net)301 static inline struct ppp_net *ppp_pernet(struct net *net)
302 {
303 return net_generic(net, ppp_net_id);
304 }
305
306 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)307 static inline int proto_to_npindex(int proto)
308 {
309 switch (proto) {
310 case PPP_IP:
311 return NP_IP;
312 case PPP_IPV6:
313 return NP_IPV6;
314 case PPP_IPX:
315 return NP_IPX;
316 case PPP_AT:
317 return NP_AT;
318 case PPP_MPLS_UC:
319 return NP_MPLS_UC;
320 case PPP_MPLS_MC:
321 return NP_MPLS_MC;
322 }
323 return -EINVAL;
324 }
325
326 /* Translates an NP index into a PPP protocol number */
327 static const int npindex_to_proto[NUM_NP] = {
328 PPP_IP,
329 PPP_IPV6,
330 PPP_IPX,
331 PPP_AT,
332 PPP_MPLS_UC,
333 PPP_MPLS_MC,
334 };
335
336 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)337 static inline int ethertype_to_npindex(int ethertype)
338 {
339 switch (ethertype) {
340 case ETH_P_IP:
341 return NP_IP;
342 case ETH_P_IPV6:
343 return NP_IPV6;
344 case ETH_P_IPX:
345 return NP_IPX;
346 case ETH_P_PPPTALK:
347 case ETH_P_ATALK:
348 return NP_AT;
349 case ETH_P_MPLS_UC:
350 return NP_MPLS_UC;
351 case ETH_P_MPLS_MC:
352 return NP_MPLS_MC;
353 }
354 return -1;
355 }
356
357 /* Translates an NP index into an ethertype */
358 static const int npindex_to_ethertype[NUM_NP] = {
359 ETH_P_IP,
360 ETH_P_IPV6,
361 ETH_P_IPX,
362 ETH_P_PPPTALK,
363 ETH_P_MPLS_UC,
364 ETH_P_MPLS_MC,
365 };
366
367 /*
368 * Locking shorthand.
369 */
370 #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
371 #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
372 #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
373 #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
374 #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
375 ppp_recv_lock(ppp); } while (0)
376 #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
377 ppp_xmit_unlock(ppp); } while (0)
378
379 /*
380 * /dev/ppp device routines.
381 * The /dev/ppp device is used by pppd to control the ppp unit.
382 * It supports the read, write, ioctl and poll functions.
383 * Open instances of /dev/ppp can be in one of three states:
384 * unattached, attached to a ppp unit, or attached to a ppp channel.
385 */
ppp_open(struct inode * inode,struct file * file)386 static int ppp_open(struct inode *inode, struct file *file)
387 {
388 /*
389 * This could (should?) be enforced by the permissions on /dev/ppp.
390 */
391 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
392 return -EPERM;
393 return 0;
394 }
395
ppp_release(struct inode * unused,struct file * file)396 static int ppp_release(struct inode *unused, struct file *file)
397 {
398 struct ppp_file *pf = file->private_data;
399 struct ppp *ppp;
400
401 if (pf) {
402 file->private_data = NULL;
403 if (pf->kind == INTERFACE) {
404 ppp = PF_TO_PPP(pf);
405 rtnl_lock();
406 if (file == ppp->owner)
407 unregister_netdevice(ppp->dev);
408 rtnl_unlock();
409 }
410 if (refcount_dec_and_test(&pf->refcnt)) {
411 switch (pf->kind) {
412 case INTERFACE:
413 ppp_destroy_interface(PF_TO_PPP(pf));
414 break;
415 case CHANNEL:
416 ppp_destroy_channel(PF_TO_CHANNEL(pf));
417 break;
418 }
419 }
420 }
421 return 0;
422 }
423
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)424 static ssize_t ppp_read(struct file *file, char __user *buf,
425 size_t count, loff_t *ppos)
426 {
427 struct ppp_file *pf = file->private_data;
428 DECLARE_WAITQUEUE(wait, current);
429 ssize_t ret;
430 struct sk_buff *skb = NULL;
431 struct iovec iov;
432 struct iov_iter to;
433
434 ret = count;
435
436 if (!pf)
437 return -ENXIO;
438 add_wait_queue(&pf->rwait, &wait);
439 for (;;) {
440 set_current_state(TASK_INTERRUPTIBLE);
441 skb = skb_dequeue(&pf->rq);
442 if (skb)
443 break;
444 ret = 0;
445 if (pf->dead)
446 break;
447 if (pf->kind == INTERFACE) {
448 /*
449 * Return 0 (EOF) on an interface that has no
450 * channels connected, unless it is looping
451 * network traffic (demand mode).
452 */
453 struct ppp *ppp = PF_TO_PPP(pf);
454
455 ppp_recv_lock(ppp);
456 if (ppp->n_channels == 0 &&
457 (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
458 ppp_recv_unlock(ppp);
459 break;
460 }
461 ppp_recv_unlock(ppp);
462 }
463 ret = -EAGAIN;
464 if (file->f_flags & O_NONBLOCK)
465 break;
466 ret = -ERESTARTSYS;
467 if (signal_pending(current))
468 break;
469 schedule();
470 }
471 set_current_state(TASK_RUNNING);
472 remove_wait_queue(&pf->rwait, &wait);
473
474 if (!skb)
475 goto out;
476
477 ret = -EOVERFLOW;
478 if (skb->len > count)
479 goto outf;
480 ret = -EFAULT;
481 iov.iov_base = buf;
482 iov.iov_len = count;
483 iov_iter_init(&to, ITER_DEST, &iov, 1, count);
484 if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
485 goto outf;
486 ret = skb->len;
487
488 outf:
489 kfree_skb(skb);
490 out:
491 return ret;
492 }
493
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)494 static ssize_t ppp_write(struct file *file, const char __user *buf,
495 size_t count, loff_t *ppos)
496 {
497 struct ppp_file *pf = file->private_data;
498 struct sk_buff *skb;
499 ssize_t ret;
500
501 if (!pf)
502 return -ENXIO;
503 /* All PPP packets should start with the 2-byte protocol */
504 if (count < PPP_PROTO_LEN)
505 return -EINVAL;
506 ret = -ENOMEM;
507 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
508 if (!skb)
509 goto out;
510 skb_reserve(skb, pf->hdrlen);
511 ret = -EFAULT;
512 if (copy_from_user(skb_put(skb, count), buf, count)) {
513 kfree_skb(skb);
514 goto out;
515 }
516
517 switch (pf->kind) {
518 case INTERFACE:
519 ppp_xmit_process(PF_TO_PPP(pf), skb);
520 break;
521 case CHANNEL:
522 skb_queue_tail(&pf->xq, skb);
523 ppp_channel_push(PF_TO_CHANNEL(pf));
524 break;
525 }
526
527 ret = count;
528
529 out:
530 return ret;
531 }
532
533 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)534 static __poll_t ppp_poll(struct file *file, poll_table *wait)
535 {
536 struct ppp_file *pf = file->private_data;
537 __poll_t mask;
538
539 if (!pf)
540 return 0;
541 poll_wait(file, &pf->rwait, wait);
542 mask = EPOLLOUT | EPOLLWRNORM;
543 if (skb_peek(&pf->rq))
544 mask |= EPOLLIN | EPOLLRDNORM;
545 if (pf->dead)
546 mask |= EPOLLHUP;
547 else if (pf->kind == INTERFACE) {
548 /* see comment in ppp_read */
549 struct ppp *ppp = PF_TO_PPP(pf);
550
551 ppp_recv_lock(ppp);
552 if (ppp->n_channels == 0 &&
553 (ppp->flags & SC_LOOP_TRAFFIC) == 0)
554 mask |= EPOLLIN | EPOLLRDNORM;
555 ppp_recv_unlock(ppp);
556 }
557
558 return mask;
559 }
560
561 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)562 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
563 {
564 struct sock_fprog_kern fprog;
565 struct bpf_prog *res = NULL;
566 int err;
567
568 if (!uprog->len)
569 return NULL;
570
571 /* uprog->len is unsigned short, so no overflow here */
572 fprog.len = uprog->len;
573 fprog.filter = memdup_user(uprog->filter,
574 uprog->len * sizeof(struct sock_filter));
575 if (IS_ERR(fprog.filter))
576 return ERR_CAST(fprog.filter);
577
578 err = bpf_prog_create(&res, &fprog);
579 kfree(fprog.filter);
580
581 return err ? ERR_PTR(err) : res;
582 }
583
ppp_get_filter(struct sock_fprog __user * p)584 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
585 {
586 struct sock_fprog uprog;
587
588 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
589 return ERR_PTR(-EFAULT);
590 return get_filter(&uprog);
591 }
592
593 #ifdef CONFIG_COMPAT
594 struct sock_fprog32 {
595 unsigned short len;
596 compat_caddr_t filter;
597 };
598
599 #define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32)
600 #define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32)
601
compat_ppp_get_filter(struct sock_fprog32 __user * p)602 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
603 {
604 struct sock_fprog32 uprog32;
605 struct sock_fprog uprog;
606
607 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
608 return ERR_PTR(-EFAULT);
609 uprog.len = uprog32.len;
610 uprog.filter = compat_ptr(uprog32.filter);
611 return get_filter(&uprog);
612 }
613 #endif
614 #endif
615
616 /* Bridge one PPP channel to another.
617 * When two channels are bridged, ppp_input on one channel is redirected to
618 * the other's ops->start_xmit handler.
619 * In order to safely bridge channels we must reject channels which are already
620 * part of a bridge instance, or which form part of an existing unit.
621 * Once successfully bridged, each channel holds a reference on the other
622 * to prevent it being freed while the bridge is extant.
623 */
ppp_bridge_channels(struct channel * pch,struct channel * pchb)624 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
625 {
626 write_lock_bh(&pch->upl);
627 if (pch->ppp ||
628 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
629 write_unlock_bh(&pch->upl);
630 return -EALREADY;
631 }
632 refcount_inc(&pchb->file.refcnt);
633 rcu_assign_pointer(pch->bridge, pchb);
634 write_unlock_bh(&pch->upl);
635
636 write_lock_bh(&pchb->upl);
637 if (pchb->ppp ||
638 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
639 write_unlock_bh(&pchb->upl);
640 goto err_unset;
641 }
642 refcount_inc(&pch->file.refcnt);
643 rcu_assign_pointer(pchb->bridge, pch);
644 write_unlock_bh(&pchb->upl);
645
646 return 0;
647
648 err_unset:
649 write_lock_bh(&pch->upl);
650 /* Re-read pch->bridge with upl held in case it was modified concurrently */
651 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
652 RCU_INIT_POINTER(pch->bridge, NULL);
653 write_unlock_bh(&pch->upl);
654 synchronize_rcu();
655
656 if (pchb)
657 if (refcount_dec_and_test(&pchb->file.refcnt))
658 ppp_destroy_channel(pchb);
659
660 return -EALREADY;
661 }
662
ppp_unbridge_channels(struct channel * pch)663 static int ppp_unbridge_channels(struct channel *pch)
664 {
665 struct channel *pchb, *pchbb;
666
667 write_lock_bh(&pch->upl);
668 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
669 if (!pchb) {
670 write_unlock_bh(&pch->upl);
671 return -EINVAL;
672 }
673 RCU_INIT_POINTER(pch->bridge, NULL);
674 write_unlock_bh(&pch->upl);
675
676 /* Only modify pchb if phcb->bridge points back to pch.
677 * If not, it implies that there has been a race unbridging (and possibly
678 * even rebridging) pchb. We should leave pchb alone to avoid either a
679 * refcount underflow, or breaking another established bridge instance.
680 */
681 write_lock_bh(&pchb->upl);
682 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
683 if (pchbb == pch)
684 RCU_INIT_POINTER(pchb->bridge, NULL);
685 write_unlock_bh(&pchb->upl);
686
687 synchronize_rcu();
688
689 if (pchbb == pch)
690 if (refcount_dec_and_test(&pch->file.refcnt))
691 ppp_destroy_channel(pch);
692
693 if (refcount_dec_and_test(&pchb->file.refcnt))
694 ppp_destroy_channel(pchb);
695
696 return 0;
697 }
698
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)699 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
700 {
701 struct ppp_file *pf;
702 struct ppp *ppp;
703 int err = -EFAULT, val, val2, i;
704 struct ppp_idle32 idle32;
705 struct ppp_idle64 idle64;
706 struct npioctl npi;
707 int unit, cflags;
708 struct slcompress *vj;
709 void __user *argp = (void __user *)arg;
710 int __user *p = argp;
711
712 mutex_lock(&ppp_mutex);
713
714 pf = file->private_data;
715 if (!pf) {
716 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
717 pf, file, cmd, arg);
718 goto out;
719 }
720
721 if (cmd == PPPIOCDETACH) {
722 /*
723 * PPPIOCDETACH is no longer supported as it was heavily broken,
724 * and is only known to have been used by pppd older than
725 * ppp-2.4.2 (released November 2003).
726 */
727 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
728 current->comm, current->pid);
729 err = -EINVAL;
730 goto out;
731 }
732
733 if (pf->kind == CHANNEL) {
734 struct channel *pch, *pchb;
735 struct ppp_channel *chan;
736 struct ppp_net *pn;
737
738 pch = PF_TO_CHANNEL(pf);
739
740 switch (cmd) {
741 case PPPIOCCONNECT:
742 if (get_user(unit, p))
743 break;
744 err = ppp_connect_channel(pch, unit);
745 break;
746
747 case PPPIOCDISCONN:
748 err = ppp_disconnect_channel(pch);
749 break;
750
751 case PPPIOCBRIDGECHAN:
752 if (get_user(unit, p))
753 break;
754 err = -ENXIO;
755 pn = ppp_pernet(current->nsproxy->net_ns);
756 spin_lock_bh(&pn->all_channels_lock);
757 pchb = ppp_find_channel(pn, unit);
758 /* Hold a reference to prevent pchb being freed while
759 * we establish the bridge.
760 */
761 if (pchb)
762 refcount_inc(&pchb->file.refcnt);
763 spin_unlock_bh(&pn->all_channels_lock);
764 if (!pchb)
765 break;
766 err = ppp_bridge_channels(pch, pchb);
767 /* Drop earlier refcount now bridge establishment is complete */
768 if (refcount_dec_and_test(&pchb->file.refcnt))
769 ppp_destroy_channel(pchb);
770 break;
771
772 case PPPIOCUNBRIDGECHAN:
773 err = ppp_unbridge_channels(pch);
774 break;
775
776 default:
777 down_read(&pch->chan_sem);
778 chan = pch->chan;
779 err = -ENOTTY;
780 if (chan && chan->ops->ioctl)
781 err = chan->ops->ioctl(chan, cmd, arg);
782 up_read(&pch->chan_sem);
783 }
784 goto out;
785 }
786
787 if (pf->kind != INTERFACE) {
788 /* can't happen */
789 pr_err("PPP: not interface or channel??\n");
790 err = -EINVAL;
791 goto out;
792 }
793
794 ppp = PF_TO_PPP(pf);
795 switch (cmd) {
796 case PPPIOCSMRU:
797 if (get_user(val, p))
798 break;
799 ppp->mru = val;
800 err = 0;
801 break;
802
803 case PPPIOCSFLAGS:
804 if (get_user(val, p))
805 break;
806 ppp_lock(ppp);
807 cflags = ppp->flags & ~val;
808 #ifdef CONFIG_PPP_MULTILINK
809 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
810 ppp->nextseq = 0;
811 #endif
812 ppp->flags = val & SC_FLAG_BITS;
813 ppp_unlock(ppp);
814 if (cflags & SC_CCP_OPEN)
815 ppp_ccp_closed(ppp);
816 err = 0;
817 break;
818
819 case PPPIOCGFLAGS:
820 val = ppp->flags | ppp->xstate | ppp->rstate;
821 if (put_user(val, p))
822 break;
823 err = 0;
824 break;
825
826 case PPPIOCSCOMPRESS:
827 {
828 struct ppp_option_data data;
829 if (copy_from_user(&data, argp, sizeof(data)))
830 err = -EFAULT;
831 else
832 err = ppp_set_compress(ppp, &data);
833 break;
834 }
835 case PPPIOCGUNIT:
836 if (put_user(ppp->file.index, p))
837 break;
838 err = 0;
839 break;
840
841 case PPPIOCSDEBUG:
842 if (get_user(val, p))
843 break;
844 ppp->debug = val;
845 err = 0;
846 break;
847
848 case PPPIOCGDEBUG:
849 if (put_user(ppp->debug, p))
850 break;
851 err = 0;
852 break;
853
854 case PPPIOCGIDLE32:
855 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
856 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
857 if (copy_to_user(argp, &idle32, sizeof(idle32)))
858 break;
859 err = 0;
860 break;
861
862 case PPPIOCGIDLE64:
863 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
864 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
865 if (copy_to_user(argp, &idle64, sizeof(idle64)))
866 break;
867 err = 0;
868 break;
869
870 case PPPIOCSMAXCID:
871 if (get_user(val, p))
872 break;
873 val2 = 15;
874 if ((val >> 16) != 0) {
875 val2 = val >> 16;
876 val &= 0xffff;
877 }
878 vj = slhc_init(val2+1, val+1);
879 if (IS_ERR(vj)) {
880 err = PTR_ERR(vj);
881 break;
882 }
883 ppp_lock(ppp);
884 if (ppp->vj)
885 slhc_free(ppp->vj);
886 ppp->vj = vj;
887 ppp_unlock(ppp);
888 err = 0;
889 break;
890
891 case PPPIOCGNPMODE:
892 case PPPIOCSNPMODE:
893 if (copy_from_user(&npi, argp, sizeof(npi)))
894 break;
895 err = proto_to_npindex(npi.protocol);
896 if (err < 0)
897 break;
898 i = err;
899 if (cmd == PPPIOCGNPMODE) {
900 err = -EFAULT;
901 npi.mode = ppp->npmode[i];
902 if (copy_to_user(argp, &npi, sizeof(npi)))
903 break;
904 } else {
905 ppp->npmode[i] = npi.mode;
906 /* we may be able to transmit more packets now (??) */
907 netif_wake_queue(ppp->dev);
908 }
909 err = 0;
910 break;
911
912 #ifdef CONFIG_PPP_FILTER
913 case PPPIOCSPASS:
914 case PPPIOCSACTIVE:
915 {
916 struct bpf_prog *filter = ppp_get_filter(argp);
917 struct bpf_prog **which;
918
919 if (IS_ERR(filter)) {
920 err = PTR_ERR(filter);
921 break;
922 }
923 if (cmd == PPPIOCSPASS)
924 which = &ppp->pass_filter;
925 else
926 which = &ppp->active_filter;
927 ppp_lock(ppp);
928 if (*which)
929 bpf_prog_destroy(*which);
930 *which = filter;
931 ppp_unlock(ppp);
932 err = 0;
933 break;
934 }
935 #endif /* CONFIG_PPP_FILTER */
936
937 #ifdef CONFIG_PPP_MULTILINK
938 case PPPIOCSMRRU:
939 if (get_user(val, p))
940 break;
941 ppp_recv_lock(ppp);
942 ppp->mrru = val;
943 ppp_recv_unlock(ppp);
944 err = 0;
945 break;
946 #endif /* CONFIG_PPP_MULTILINK */
947
948 default:
949 err = -ENOTTY;
950 }
951
952 out:
953 mutex_unlock(&ppp_mutex);
954
955 return err;
956 }
957
958 #ifdef CONFIG_COMPAT
959 struct ppp_option_data32 {
960 compat_uptr_t ptr;
961 u32 length;
962 compat_int_t transmit;
963 };
964 #define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)
965
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)966 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
967 {
968 struct ppp_file *pf;
969 int err = -ENOIOCTLCMD;
970 void __user *argp = (void __user *)arg;
971
972 mutex_lock(&ppp_mutex);
973
974 pf = file->private_data;
975 if (pf && pf->kind == INTERFACE) {
976 struct ppp *ppp = PF_TO_PPP(pf);
977 switch (cmd) {
978 #ifdef CONFIG_PPP_FILTER
979 case PPPIOCSPASS32:
980 case PPPIOCSACTIVE32:
981 {
982 struct bpf_prog *filter = compat_ppp_get_filter(argp);
983 struct bpf_prog **which;
984
985 if (IS_ERR(filter)) {
986 err = PTR_ERR(filter);
987 break;
988 }
989 if (cmd == PPPIOCSPASS32)
990 which = &ppp->pass_filter;
991 else
992 which = &ppp->active_filter;
993 ppp_lock(ppp);
994 if (*which)
995 bpf_prog_destroy(*which);
996 *which = filter;
997 ppp_unlock(ppp);
998 err = 0;
999 break;
1000 }
1001 #endif /* CONFIG_PPP_FILTER */
1002 case PPPIOCSCOMPRESS32:
1003 {
1004 struct ppp_option_data32 data32;
1005 if (copy_from_user(&data32, argp, sizeof(data32))) {
1006 err = -EFAULT;
1007 } else {
1008 struct ppp_option_data data = {
1009 .ptr = compat_ptr(data32.ptr),
1010 .length = data32.length,
1011 .transmit = data32.transmit
1012 };
1013 err = ppp_set_compress(ppp, &data);
1014 }
1015 break;
1016 }
1017 }
1018 }
1019 mutex_unlock(&ppp_mutex);
1020
1021 /* all other commands have compatible arguments */
1022 if (err == -ENOIOCTLCMD)
1023 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1024
1025 return err;
1026 }
1027 #endif
1028
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)1029 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1030 struct file *file, unsigned int cmd, unsigned long arg)
1031 {
1032 int unit, err = -EFAULT;
1033 struct ppp *ppp;
1034 struct channel *chan;
1035 struct ppp_net *pn;
1036 int __user *p = (int __user *)arg;
1037
1038 switch (cmd) {
1039 case PPPIOCNEWUNIT:
1040 /* Create a new ppp unit */
1041 if (get_user(unit, p))
1042 break;
1043 err = ppp_create_interface(net, file, &unit);
1044 if (err < 0)
1045 break;
1046
1047 err = -EFAULT;
1048 if (put_user(unit, p))
1049 break;
1050 err = 0;
1051 break;
1052
1053 case PPPIOCATTACH:
1054 /* Attach to an existing ppp unit */
1055 if (get_user(unit, p))
1056 break;
1057 err = -ENXIO;
1058 pn = ppp_pernet(net);
1059 mutex_lock(&pn->all_ppp_mutex);
1060 ppp = ppp_find_unit(pn, unit);
1061 if (ppp) {
1062 refcount_inc(&ppp->file.refcnt);
1063 file->private_data = &ppp->file;
1064 err = 0;
1065 }
1066 mutex_unlock(&pn->all_ppp_mutex);
1067 break;
1068
1069 case PPPIOCATTCHAN:
1070 if (get_user(unit, p))
1071 break;
1072 err = -ENXIO;
1073 pn = ppp_pernet(net);
1074 spin_lock_bh(&pn->all_channels_lock);
1075 chan = ppp_find_channel(pn, unit);
1076 if (chan) {
1077 refcount_inc(&chan->file.refcnt);
1078 file->private_data = &chan->file;
1079 err = 0;
1080 }
1081 spin_unlock_bh(&pn->all_channels_lock);
1082 break;
1083
1084 default:
1085 err = -ENOTTY;
1086 }
1087
1088 return err;
1089 }
1090
1091 static const struct file_operations ppp_device_fops = {
1092 .owner = THIS_MODULE,
1093 .read = ppp_read,
1094 .write = ppp_write,
1095 .poll = ppp_poll,
1096 .unlocked_ioctl = ppp_ioctl,
1097 #ifdef CONFIG_COMPAT
1098 .compat_ioctl = ppp_compat_ioctl,
1099 #endif
1100 .open = ppp_open,
1101 .release = ppp_release,
1102 .llseek = noop_llseek,
1103 };
1104
ppp_init_net(struct net * net)1105 static __net_init int ppp_init_net(struct net *net)
1106 {
1107 struct ppp_net *pn = net_generic(net, ppp_net_id);
1108
1109 idr_init(&pn->units_idr);
1110 mutex_init(&pn->all_ppp_mutex);
1111
1112 INIT_LIST_HEAD(&pn->all_channels);
1113 INIT_LIST_HEAD(&pn->new_channels);
1114
1115 spin_lock_init(&pn->all_channels_lock);
1116
1117 return 0;
1118 }
1119
ppp_exit_net(struct net * net)1120 static __net_exit void ppp_exit_net(struct net *net)
1121 {
1122 struct ppp_net *pn = net_generic(net, ppp_net_id);
1123 struct net_device *dev;
1124 struct net_device *aux;
1125 struct ppp *ppp;
1126 LIST_HEAD(list);
1127 int id;
1128
1129 rtnl_lock();
1130 for_each_netdev_safe(net, dev, aux) {
1131 if (dev->netdev_ops == &ppp_netdev_ops)
1132 unregister_netdevice_queue(dev, &list);
1133 }
1134
1135 idr_for_each_entry(&pn->units_idr, ppp, id)
1136 /* Skip devices already unregistered by previous loop */
1137 if (!net_eq(dev_net(ppp->dev), net))
1138 unregister_netdevice_queue(ppp->dev, &list);
1139
1140 unregister_netdevice_many(&list);
1141 rtnl_unlock();
1142
1143 mutex_destroy(&pn->all_ppp_mutex);
1144 idr_destroy(&pn->units_idr);
1145 WARN_ON_ONCE(!list_empty(&pn->all_channels));
1146 WARN_ON_ONCE(!list_empty(&pn->new_channels));
1147 }
1148
1149 static struct pernet_operations ppp_net_ops = {
1150 .init = ppp_init_net,
1151 .exit = ppp_exit_net,
1152 .id = &ppp_net_id,
1153 .size = sizeof(struct ppp_net),
1154 };
1155
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1156 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1157 {
1158 struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1159 int ret;
1160
1161 mutex_lock(&pn->all_ppp_mutex);
1162
1163 if (unit < 0) {
1164 ret = unit_get(&pn->units_idr, ppp, 0);
1165 if (ret < 0)
1166 goto err;
1167 if (!ifname_is_set) {
1168 while (1) {
1169 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1170 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1171 break;
1172 unit_put(&pn->units_idr, ret);
1173 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1174 if (ret < 0)
1175 goto err;
1176 }
1177 }
1178 } else {
1179 /* Caller asked for a specific unit number. Fail with -EEXIST
1180 * if unavailable. For backward compatibility, return -EEXIST
1181 * too if idr allocation fails; this makes pppd retry without
1182 * requesting a specific unit number.
1183 */
1184 if (unit_find(&pn->units_idr, unit)) {
1185 ret = -EEXIST;
1186 goto err;
1187 }
1188 ret = unit_set(&pn->units_idr, ppp, unit);
1189 if (ret < 0) {
1190 /* Rewrite error for backward compatibility */
1191 ret = -EEXIST;
1192 goto err;
1193 }
1194 }
1195 ppp->file.index = ret;
1196
1197 if (!ifname_is_set)
1198 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1199
1200 mutex_unlock(&pn->all_ppp_mutex);
1201
1202 ret = register_netdevice(ppp->dev);
1203 if (ret < 0)
1204 goto err_unit;
1205
1206 atomic_inc(&ppp_unit_count);
1207
1208 return 0;
1209
1210 err_unit:
1211 mutex_lock(&pn->all_ppp_mutex);
1212 unit_put(&pn->units_idr, ppp->file.index);
1213 err:
1214 mutex_unlock(&pn->all_ppp_mutex);
1215
1216 return ret;
1217 }
1218
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1219 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1220 const struct ppp_config *conf)
1221 {
1222 struct ppp *ppp = netdev_priv(dev);
1223 int indx;
1224 int err;
1225 int cpu;
1226
1227 ppp->dev = dev;
1228 ppp->ppp_net = src_net;
1229 ppp->mru = PPP_MRU;
1230 ppp->owner = conf->file;
1231
1232 init_ppp_file(&ppp->file, INTERFACE);
1233 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1234
1235 for (indx = 0; indx < NUM_NP; ++indx)
1236 ppp->npmode[indx] = NPMODE_PASS;
1237 INIT_LIST_HEAD(&ppp->channels);
1238 spin_lock_init(&ppp->rlock);
1239 spin_lock_init(&ppp->wlock);
1240
1241 ppp->xmit_recursion = alloc_percpu(int);
1242 if (!ppp->xmit_recursion) {
1243 err = -ENOMEM;
1244 goto err1;
1245 }
1246 for_each_possible_cpu(cpu)
1247 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1248
1249 #ifdef CONFIG_PPP_MULTILINK
1250 ppp->minseq = -1;
1251 skb_queue_head_init(&ppp->mrq);
1252 #endif /* CONFIG_PPP_MULTILINK */
1253 #ifdef CONFIG_PPP_FILTER
1254 ppp->pass_filter = NULL;
1255 ppp->active_filter = NULL;
1256 #endif /* CONFIG_PPP_FILTER */
1257
1258 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1259 if (err < 0)
1260 goto err2;
1261
1262 conf->file->private_data = &ppp->file;
1263
1264 return 0;
1265 err2:
1266 free_percpu(ppp->xmit_recursion);
1267 err1:
1268 return err;
1269 }
1270
1271 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1272 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
1273 };
1274
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1275 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1276 struct netlink_ext_ack *extack)
1277 {
1278 if (!data)
1279 return -EINVAL;
1280
1281 if (!data[IFLA_PPP_DEV_FD])
1282 return -EINVAL;
1283 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1284 return -EBADF;
1285
1286 return 0;
1287 }
1288
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1289 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1290 struct nlattr *tb[], struct nlattr *data[],
1291 struct netlink_ext_ack *extack)
1292 {
1293 struct ppp_config conf = {
1294 .unit = -1,
1295 .ifname_is_set = true,
1296 };
1297 struct file *file;
1298 int err;
1299
1300 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1301 if (!file)
1302 return -EBADF;
1303
1304 /* rtnl_lock is already held here, but ppp_create_interface() locks
1305 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1306 * possible deadlock due to lock order inversion, at the cost of
1307 * pushing the problem back to userspace.
1308 */
1309 if (!mutex_trylock(&ppp_mutex)) {
1310 err = -EBUSY;
1311 goto out;
1312 }
1313
1314 if (file->f_op != &ppp_device_fops || file->private_data) {
1315 err = -EBADF;
1316 goto out_unlock;
1317 }
1318
1319 conf.file = file;
1320
1321 /* Don't use device name generated by the rtnetlink layer when ifname
1322 * isn't specified. Let ppp_dev_configure() set the device name using
1323 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1324 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1325 */
1326 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1327 conf.ifname_is_set = false;
1328
1329 err = ppp_dev_configure(src_net, dev, &conf);
1330
1331 out_unlock:
1332 mutex_unlock(&ppp_mutex);
1333 out:
1334 fput(file);
1335
1336 return err;
1337 }
1338
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1339 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1340 {
1341 unregister_netdevice_queue(dev, head);
1342 }
1343
ppp_nl_get_size(const struct net_device * dev)1344 static size_t ppp_nl_get_size(const struct net_device *dev)
1345 {
1346 return 0;
1347 }
1348
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1349 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1350 {
1351 return 0;
1352 }
1353
ppp_nl_get_link_net(const struct net_device * dev)1354 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1355 {
1356 struct ppp *ppp = netdev_priv(dev);
1357
1358 return ppp->ppp_net;
1359 }
1360
1361 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1362 .kind = "ppp",
1363 .maxtype = IFLA_PPP_MAX,
1364 .policy = ppp_nl_policy,
1365 .priv_size = sizeof(struct ppp),
1366 .setup = ppp_setup,
1367 .validate = ppp_nl_validate,
1368 .newlink = ppp_nl_newlink,
1369 .dellink = ppp_nl_dellink,
1370 .get_size = ppp_nl_get_size,
1371 .fill_info = ppp_nl_fill_info,
1372 .get_link_net = ppp_nl_get_link_net,
1373 };
1374
1375 #define PPP_MAJOR 108
1376
1377 /* Called at boot time if ppp is compiled into the kernel,
1378 or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1379 static int __init ppp_init(void)
1380 {
1381 int err;
1382
1383 pr_info("PPP generic driver version " PPP_VERSION "\n");
1384
1385 err = register_pernet_device(&ppp_net_ops);
1386 if (err) {
1387 pr_err("failed to register PPP pernet device (%d)\n", err);
1388 goto out;
1389 }
1390
1391 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1392 if (err) {
1393 pr_err("failed to register PPP device (%d)\n", err);
1394 goto out_net;
1395 }
1396
1397 ppp_class = class_create(THIS_MODULE, "ppp");
1398 if (IS_ERR(ppp_class)) {
1399 err = PTR_ERR(ppp_class);
1400 goto out_chrdev;
1401 }
1402
1403 err = rtnl_link_register(&ppp_link_ops);
1404 if (err) {
1405 pr_err("failed to register rtnetlink PPP handler\n");
1406 goto out_class;
1407 }
1408
1409 /* not a big deal if we fail here :-) */
1410 device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1411
1412 return 0;
1413
1414 out_class:
1415 class_destroy(ppp_class);
1416 out_chrdev:
1417 unregister_chrdev(PPP_MAJOR, "ppp");
1418 out_net:
1419 unregister_pernet_device(&ppp_net_ops);
1420 out:
1421 return err;
1422 }
1423
1424 /*
1425 * Network interface unit routines.
1426 */
1427 static netdev_tx_t
ppp_start_xmit(struct sk_buff * skb,struct net_device * dev)1428 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1429 {
1430 struct ppp *ppp = netdev_priv(dev);
1431 int npi, proto;
1432 unsigned char *pp;
1433
1434 npi = ethertype_to_npindex(ntohs(skb->protocol));
1435 if (npi < 0)
1436 goto outf;
1437
1438 /* Drop, accept or reject the packet */
1439 switch (ppp->npmode[npi]) {
1440 case NPMODE_PASS:
1441 break;
1442 case NPMODE_QUEUE:
1443 /* it would be nice to have a way to tell the network
1444 system to queue this one up for later. */
1445 goto outf;
1446 case NPMODE_DROP:
1447 case NPMODE_ERROR:
1448 goto outf;
1449 }
1450
1451 /* Put the 2-byte PPP protocol number on the front,
1452 making sure there is room for the address and control fields. */
1453 if (skb_cow_head(skb, PPP_HDRLEN))
1454 goto outf;
1455
1456 pp = skb_push(skb, 2);
1457 proto = npindex_to_proto[npi];
1458 put_unaligned_be16(proto, pp);
1459
1460 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1461 ppp_xmit_process(ppp, skb);
1462
1463 return NETDEV_TX_OK;
1464
1465 outf:
1466 kfree_skb(skb);
1467 ++dev->stats.tx_dropped;
1468 return NETDEV_TX_OK;
1469 }
1470
1471 static int
ppp_net_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * addr,int cmd)1472 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1473 void __user *addr, int cmd)
1474 {
1475 struct ppp *ppp = netdev_priv(dev);
1476 int err = -EFAULT;
1477 struct ppp_stats stats;
1478 struct ppp_comp_stats cstats;
1479 char *vers;
1480
1481 switch (cmd) {
1482 case SIOCGPPPSTATS:
1483 ppp_get_stats(ppp, &stats);
1484 if (copy_to_user(addr, &stats, sizeof(stats)))
1485 break;
1486 err = 0;
1487 break;
1488
1489 case SIOCGPPPCSTATS:
1490 memset(&cstats, 0, sizeof(cstats));
1491 if (ppp->xc_state)
1492 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1493 if (ppp->rc_state)
1494 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1495 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1496 break;
1497 err = 0;
1498 break;
1499
1500 case SIOCGPPPVER:
1501 vers = PPP_VERSION;
1502 if (copy_to_user(addr, vers, strlen(vers) + 1))
1503 break;
1504 err = 0;
1505 break;
1506
1507 default:
1508 err = -EINVAL;
1509 }
1510
1511 return err;
1512 }
1513
1514 static void
ppp_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats64)1515 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1516 {
1517 struct ppp *ppp = netdev_priv(dev);
1518
1519 ppp_recv_lock(ppp);
1520 stats64->rx_packets = ppp->stats64.rx_packets;
1521 stats64->rx_bytes = ppp->stats64.rx_bytes;
1522 ppp_recv_unlock(ppp);
1523
1524 ppp_xmit_lock(ppp);
1525 stats64->tx_packets = ppp->stats64.tx_packets;
1526 stats64->tx_bytes = ppp->stats64.tx_bytes;
1527 ppp_xmit_unlock(ppp);
1528
1529 stats64->rx_errors = dev->stats.rx_errors;
1530 stats64->tx_errors = dev->stats.tx_errors;
1531 stats64->rx_dropped = dev->stats.rx_dropped;
1532 stats64->tx_dropped = dev->stats.tx_dropped;
1533 stats64->rx_length_errors = dev->stats.rx_length_errors;
1534 }
1535
ppp_dev_init(struct net_device * dev)1536 static int ppp_dev_init(struct net_device *dev)
1537 {
1538 struct ppp *ppp;
1539
1540 netdev_lockdep_set_classes(dev);
1541
1542 ppp = netdev_priv(dev);
1543 /* Let the netdevice take a reference on the ppp file. This ensures
1544 * that ppp_destroy_interface() won't run before the device gets
1545 * unregistered.
1546 */
1547 refcount_inc(&ppp->file.refcnt);
1548
1549 return 0;
1550 }
1551
ppp_dev_uninit(struct net_device * dev)1552 static void ppp_dev_uninit(struct net_device *dev)
1553 {
1554 struct ppp *ppp = netdev_priv(dev);
1555 struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1556
1557 ppp_lock(ppp);
1558 ppp->closing = 1;
1559 ppp_unlock(ppp);
1560
1561 mutex_lock(&pn->all_ppp_mutex);
1562 unit_put(&pn->units_idr, ppp->file.index);
1563 mutex_unlock(&pn->all_ppp_mutex);
1564
1565 ppp->owner = NULL;
1566
1567 ppp->file.dead = 1;
1568 wake_up_interruptible(&ppp->file.rwait);
1569 }
1570
ppp_dev_priv_destructor(struct net_device * dev)1571 static void ppp_dev_priv_destructor(struct net_device *dev)
1572 {
1573 struct ppp *ppp;
1574
1575 ppp = netdev_priv(dev);
1576 if (refcount_dec_and_test(&ppp->file.refcnt))
1577 ppp_destroy_interface(ppp);
1578 }
1579
ppp_fill_forward_path(struct net_device_path_ctx * ctx,struct net_device_path * path)1580 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1581 struct net_device_path *path)
1582 {
1583 struct ppp *ppp = netdev_priv(ctx->dev);
1584 struct ppp_channel *chan;
1585 struct channel *pch;
1586
1587 if (ppp->flags & SC_MULTILINK)
1588 return -EOPNOTSUPP;
1589
1590 if (list_empty(&ppp->channels))
1591 return -ENODEV;
1592
1593 pch = list_first_entry(&ppp->channels, struct channel, clist);
1594 chan = pch->chan;
1595 if (!chan->ops->fill_forward_path)
1596 return -EOPNOTSUPP;
1597
1598 return chan->ops->fill_forward_path(ctx, path, chan);
1599 }
1600
1601 static const struct net_device_ops ppp_netdev_ops = {
1602 .ndo_init = ppp_dev_init,
1603 .ndo_uninit = ppp_dev_uninit,
1604 .ndo_start_xmit = ppp_start_xmit,
1605 .ndo_siocdevprivate = ppp_net_siocdevprivate,
1606 .ndo_get_stats64 = ppp_get_stats64,
1607 .ndo_fill_forward_path = ppp_fill_forward_path,
1608 };
1609
1610 static struct device_type ppp_type = {
1611 .name = "ppp",
1612 };
1613
ppp_setup(struct net_device * dev)1614 static void ppp_setup(struct net_device *dev)
1615 {
1616 dev->netdev_ops = &ppp_netdev_ops;
1617 SET_NETDEV_DEVTYPE(dev, &ppp_type);
1618
1619 dev->features |= NETIF_F_LLTX;
1620
1621 dev->hard_header_len = PPP_HDRLEN;
1622 dev->mtu = PPP_MRU;
1623 dev->addr_len = 0;
1624 dev->tx_queue_len = 3;
1625 dev->type = ARPHRD_PPP;
1626 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1627 dev->priv_destructor = ppp_dev_priv_destructor;
1628 netif_keep_dst(dev);
1629 }
1630
1631 /*
1632 * Transmit-side routines.
1633 */
1634
1635 /* Called to do any work queued up on the transmit side that can now be done */
__ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1636 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1637 {
1638 ppp_xmit_lock(ppp);
1639 if (!ppp->closing) {
1640 ppp_push(ppp);
1641
1642 if (skb)
1643 skb_queue_tail(&ppp->file.xq, skb);
1644 while (!ppp->xmit_pending &&
1645 (skb = skb_dequeue(&ppp->file.xq)))
1646 ppp_send_frame(ppp, skb);
1647 /* If there's no work left to do, tell the core net
1648 code that we can accept some more. */
1649 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1650 netif_wake_queue(ppp->dev);
1651 else
1652 netif_stop_queue(ppp->dev);
1653 } else {
1654 kfree_skb(skb);
1655 }
1656 ppp_xmit_unlock(ppp);
1657 }
1658
ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1659 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1660 {
1661 local_bh_disable();
1662
1663 if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1664 goto err;
1665
1666 (*this_cpu_ptr(ppp->xmit_recursion))++;
1667 __ppp_xmit_process(ppp, skb);
1668 (*this_cpu_ptr(ppp->xmit_recursion))--;
1669
1670 local_bh_enable();
1671
1672 return;
1673
1674 err:
1675 local_bh_enable();
1676
1677 kfree_skb(skb);
1678
1679 if (net_ratelimit())
1680 netdev_err(ppp->dev, "recursion detected\n");
1681 }
1682
1683 static inline struct sk_buff *
pad_compress_skb(struct ppp * ppp,struct sk_buff * skb)1684 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1685 {
1686 struct sk_buff *new_skb;
1687 int len;
1688 int new_skb_size = ppp->dev->mtu +
1689 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1690 int compressor_skb_size = ppp->dev->mtu +
1691 ppp->xcomp->comp_extra + PPP_HDRLEN;
1692 new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1693 if (!new_skb) {
1694 if (net_ratelimit())
1695 netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1696 return NULL;
1697 }
1698 if (ppp->dev->hard_header_len > PPP_HDRLEN)
1699 skb_reserve(new_skb,
1700 ppp->dev->hard_header_len - PPP_HDRLEN);
1701
1702 /* compressor still expects A/C bytes in hdr */
1703 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1704 new_skb->data, skb->len + 2,
1705 compressor_skb_size);
1706 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1707 consume_skb(skb);
1708 skb = new_skb;
1709 skb_put(skb, len);
1710 skb_pull(skb, 2); /* pull off A/C bytes */
1711 } else if (len == 0) {
1712 /* didn't compress, or CCP not up yet */
1713 consume_skb(new_skb);
1714 new_skb = skb;
1715 } else {
1716 /*
1717 * (len < 0)
1718 * MPPE requires that we do not send unencrypted
1719 * frames. The compressor will return -1 if we
1720 * should drop the frame. We cannot simply test
1721 * the compress_proto because MPPE and MPPC share
1722 * the same number.
1723 */
1724 if (net_ratelimit())
1725 netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1726 kfree_skb(skb);
1727 consume_skb(new_skb);
1728 new_skb = NULL;
1729 }
1730 return new_skb;
1731 }
1732
1733 /*
1734 * Compress and send a frame.
1735 * The caller should have locked the xmit path,
1736 * and xmit_pending should be 0.
1737 */
1738 static void
ppp_send_frame(struct ppp * ppp,struct sk_buff * skb)1739 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1740 {
1741 int proto = PPP_PROTO(skb);
1742 struct sk_buff *new_skb;
1743 int len;
1744 unsigned char *cp;
1745
1746 skb->dev = ppp->dev;
1747
1748 if (proto < 0x8000) {
1749 #ifdef CONFIG_PPP_FILTER
1750 /* check if we should pass this packet */
1751 /* the filter instructions are constructed assuming
1752 a four-byte PPP header on each packet */
1753 *(u8 *)skb_push(skb, 2) = 1;
1754 if (ppp->pass_filter &&
1755 bpf_prog_run(ppp->pass_filter, skb) == 0) {
1756 if (ppp->debug & 1)
1757 netdev_printk(KERN_DEBUG, ppp->dev,
1758 "PPP: outbound frame "
1759 "not passed\n");
1760 kfree_skb(skb);
1761 return;
1762 }
1763 /* if this packet passes the active filter, record the time */
1764 if (!(ppp->active_filter &&
1765 bpf_prog_run(ppp->active_filter, skb) == 0))
1766 ppp->last_xmit = jiffies;
1767 skb_pull(skb, 2);
1768 #else
1769 /* for data packets, record the time */
1770 ppp->last_xmit = jiffies;
1771 #endif /* CONFIG_PPP_FILTER */
1772 }
1773
1774 ++ppp->stats64.tx_packets;
1775 ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1776
1777 switch (proto) {
1778 case PPP_IP:
1779 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1780 break;
1781 /* try to do VJ TCP header compression */
1782 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1783 GFP_ATOMIC);
1784 if (!new_skb) {
1785 netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1786 goto drop;
1787 }
1788 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1789 cp = skb->data + 2;
1790 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1791 new_skb->data + 2, &cp,
1792 !(ppp->flags & SC_NO_TCP_CCID));
1793 if (cp == skb->data + 2) {
1794 /* didn't compress */
1795 consume_skb(new_skb);
1796 } else {
1797 if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1798 proto = PPP_VJC_COMP;
1799 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1800 } else {
1801 proto = PPP_VJC_UNCOMP;
1802 cp[0] = skb->data[2];
1803 }
1804 consume_skb(skb);
1805 skb = new_skb;
1806 cp = skb_put(skb, len + 2);
1807 cp[0] = 0;
1808 cp[1] = proto;
1809 }
1810 break;
1811
1812 case PPP_CCP:
1813 /* peek at outbound CCP frames */
1814 ppp_ccp_peek(ppp, skb, 0);
1815 break;
1816 }
1817
1818 /* try to do packet compression */
1819 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1820 proto != PPP_LCP && proto != PPP_CCP) {
1821 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1822 if (net_ratelimit())
1823 netdev_err(ppp->dev,
1824 "ppp: compression required but "
1825 "down - pkt dropped.\n");
1826 goto drop;
1827 }
1828 skb = pad_compress_skb(ppp, skb);
1829 if (!skb)
1830 goto drop;
1831 }
1832
1833 /*
1834 * If we are waiting for traffic (demand dialling),
1835 * queue it up for pppd to receive.
1836 */
1837 if (ppp->flags & SC_LOOP_TRAFFIC) {
1838 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1839 goto drop;
1840 skb_queue_tail(&ppp->file.rq, skb);
1841 wake_up_interruptible(&ppp->file.rwait);
1842 return;
1843 }
1844
1845 ppp->xmit_pending = skb;
1846 ppp_push(ppp);
1847 return;
1848
1849 drop:
1850 kfree_skb(skb);
1851 ++ppp->dev->stats.tx_errors;
1852 }
1853
1854 /*
1855 * Try to send the frame in xmit_pending.
1856 * The caller should have the xmit path locked.
1857 */
1858 static void
ppp_push(struct ppp * ppp)1859 ppp_push(struct ppp *ppp)
1860 {
1861 struct list_head *list;
1862 struct channel *pch;
1863 struct sk_buff *skb = ppp->xmit_pending;
1864
1865 if (!skb)
1866 return;
1867
1868 list = &ppp->channels;
1869 if (list_empty(list)) {
1870 /* nowhere to send the packet, just drop it */
1871 ppp->xmit_pending = NULL;
1872 kfree_skb(skb);
1873 return;
1874 }
1875
1876 if ((ppp->flags & SC_MULTILINK) == 0) {
1877 /* not doing multilink: send it down the first channel */
1878 list = list->next;
1879 pch = list_entry(list, struct channel, clist);
1880
1881 spin_lock(&pch->downl);
1882 if (pch->chan) {
1883 if (pch->chan->ops->start_xmit(pch->chan, skb))
1884 ppp->xmit_pending = NULL;
1885 } else {
1886 /* channel got unregistered */
1887 kfree_skb(skb);
1888 ppp->xmit_pending = NULL;
1889 }
1890 spin_unlock(&pch->downl);
1891 return;
1892 }
1893
1894 #ifdef CONFIG_PPP_MULTILINK
1895 /* Multilink: fragment the packet over as many links
1896 as can take the packet at the moment. */
1897 if (!ppp_mp_explode(ppp, skb))
1898 return;
1899 #endif /* CONFIG_PPP_MULTILINK */
1900
1901 ppp->xmit_pending = NULL;
1902 kfree_skb(skb);
1903 }
1904
1905 #ifdef CONFIG_PPP_MULTILINK
1906 static bool mp_protocol_compress __read_mostly = true;
1907 module_param(mp_protocol_compress, bool, 0644);
1908 MODULE_PARM_DESC(mp_protocol_compress,
1909 "compress protocol id in multilink fragments");
1910
1911 /*
1912 * Divide a packet to be transmitted into fragments and
1913 * send them out the individual links.
1914 */
ppp_mp_explode(struct ppp * ppp,struct sk_buff * skb)1915 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1916 {
1917 int len, totlen;
1918 int i, bits, hdrlen, mtu;
1919 int flen;
1920 int navail, nfree, nzero;
1921 int nbigger;
1922 int totspeed;
1923 int totfree;
1924 unsigned char *p, *q;
1925 struct list_head *list;
1926 struct channel *pch;
1927 struct sk_buff *frag;
1928 struct ppp_channel *chan;
1929
1930 totspeed = 0; /*total bitrate of the bundle*/
1931 nfree = 0; /* # channels which have no packet already queued */
1932 navail = 0; /* total # of usable channels (not deregistered) */
1933 nzero = 0; /* number of channels with zero speed associated*/
1934 totfree = 0; /*total # of channels available and
1935 *having no queued packets before
1936 *starting the fragmentation*/
1937
1938 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1939 i = 0;
1940 list_for_each_entry(pch, &ppp->channels, clist) {
1941 if (pch->chan) {
1942 pch->avail = 1;
1943 navail++;
1944 pch->speed = pch->chan->speed;
1945 } else {
1946 pch->avail = 0;
1947 }
1948 if (pch->avail) {
1949 if (skb_queue_empty(&pch->file.xq) ||
1950 !pch->had_frag) {
1951 if (pch->speed == 0)
1952 nzero++;
1953 else
1954 totspeed += pch->speed;
1955
1956 pch->avail = 2;
1957 ++nfree;
1958 ++totfree;
1959 }
1960 if (!pch->had_frag && i < ppp->nxchan)
1961 ppp->nxchan = i;
1962 }
1963 ++i;
1964 }
1965 /*
1966 * Don't start sending this packet unless at least half of
1967 * the channels are free. This gives much better TCP
1968 * performance if we have a lot of channels.
1969 */
1970 if (nfree == 0 || nfree < navail / 2)
1971 return 0; /* can't take now, leave it in xmit_pending */
1972
1973 /* Do protocol field compression */
1974 p = skb->data;
1975 len = skb->len;
1976 if (*p == 0 && mp_protocol_compress) {
1977 ++p;
1978 --len;
1979 }
1980
1981 totlen = len;
1982 nbigger = len % nfree;
1983
1984 /* skip to the channel after the one we last used
1985 and start at that one */
1986 list = &ppp->channels;
1987 for (i = 0; i < ppp->nxchan; ++i) {
1988 list = list->next;
1989 if (list == &ppp->channels) {
1990 i = 0;
1991 break;
1992 }
1993 }
1994
1995 /* create a fragment for each channel */
1996 bits = B;
1997 while (len > 0) {
1998 list = list->next;
1999 if (list == &ppp->channels) {
2000 i = 0;
2001 continue;
2002 }
2003 pch = list_entry(list, struct channel, clist);
2004 ++i;
2005 if (!pch->avail)
2006 continue;
2007
2008 /*
2009 * Skip this channel if it has a fragment pending already and
2010 * we haven't given a fragment to all of the free channels.
2011 */
2012 if (pch->avail == 1) {
2013 if (nfree > 0)
2014 continue;
2015 } else {
2016 pch->avail = 1;
2017 }
2018
2019 /* check the channel's mtu and whether it is still attached. */
2020 spin_lock(&pch->downl);
2021 if (pch->chan == NULL) {
2022 /* can't use this channel, it's being deregistered */
2023 if (pch->speed == 0)
2024 nzero--;
2025 else
2026 totspeed -= pch->speed;
2027
2028 spin_unlock(&pch->downl);
2029 pch->avail = 0;
2030 totlen = len;
2031 totfree--;
2032 nfree--;
2033 if (--navail == 0)
2034 break;
2035 continue;
2036 }
2037
2038 /*
2039 *if the channel speed is not set divide
2040 *the packet evenly among the free channels;
2041 *otherwise divide it according to the speed
2042 *of the channel we are going to transmit on
2043 */
2044 flen = len;
2045 if (nfree > 0) {
2046 if (pch->speed == 0) {
2047 flen = len/nfree;
2048 if (nbigger > 0) {
2049 flen++;
2050 nbigger--;
2051 }
2052 } else {
2053 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2054 ((totspeed*totfree)/pch->speed)) - hdrlen;
2055 if (nbigger > 0) {
2056 flen += ((totfree - nzero)*pch->speed)/totspeed;
2057 nbigger -= ((totfree - nzero)*pch->speed)/
2058 totspeed;
2059 }
2060 }
2061 nfree--;
2062 }
2063
2064 /*
2065 *check if we are on the last channel or
2066 *we exceded the length of the data to
2067 *fragment
2068 */
2069 if ((nfree <= 0) || (flen > len))
2070 flen = len;
2071 /*
2072 *it is not worth to tx on slow channels:
2073 *in that case from the resulting flen according to the
2074 *above formula will be equal or less than zero.
2075 *Skip the channel in this case
2076 */
2077 if (flen <= 0) {
2078 pch->avail = 2;
2079 spin_unlock(&pch->downl);
2080 continue;
2081 }
2082
2083 /*
2084 * hdrlen includes the 2-byte PPP protocol field, but the
2085 * MTU counts only the payload excluding the protocol field.
2086 * (RFC1661 Section 2)
2087 */
2088 mtu = pch->chan->mtu - (hdrlen - 2);
2089 if (mtu < 4)
2090 mtu = 4;
2091 if (flen > mtu)
2092 flen = mtu;
2093 if (flen == len)
2094 bits |= E;
2095 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2096 if (!frag)
2097 goto noskb;
2098 q = skb_put(frag, flen + hdrlen);
2099
2100 /* make the MP header */
2101 put_unaligned_be16(PPP_MP, q);
2102 if (ppp->flags & SC_MP_XSHORTSEQ) {
2103 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2104 q[3] = ppp->nxseq;
2105 } else {
2106 q[2] = bits;
2107 q[3] = ppp->nxseq >> 16;
2108 q[4] = ppp->nxseq >> 8;
2109 q[5] = ppp->nxseq;
2110 }
2111
2112 memcpy(q + hdrlen, p, flen);
2113
2114 /* try to send it down the channel */
2115 chan = pch->chan;
2116 if (!skb_queue_empty(&pch->file.xq) ||
2117 !chan->ops->start_xmit(chan, frag))
2118 skb_queue_tail(&pch->file.xq, frag);
2119 pch->had_frag = 1;
2120 p += flen;
2121 len -= flen;
2122 ++ppp->nxseq;
2123 bits = 0;
2124 spin_unlock(&pch->downl);
2125 }
2126 ppp->nxchan = i;
2127
2128 return 1;
2129
2130 noskb:
2131 spin_unlock(&pch->downl);
2132 if (ppp->debug & 1)
2133 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2134 ++ppp->dev->stats.tx_errors;
2135 ++ppp->nxseq;
2136 return 1; /* abandon the frame */
2137 }
2138 #endif /* CONFIG_PPP_MULTILINK */
2139
2140 /* Try to send data out on a channel */
__ppp_channel_push(struct channel * pch)2141 static void __ppp_channel_push(struct channel *pch)
2142 {
2143 struct sk_buff *skb;
2144 struct ppp *ppp;
2145
2146 spin_lock(&pch->downl);
2147 if (pch->chan) {
2148 while (!skb_queue_empty(&pch->file.xq)) {
2149 skb = skb_dequeue(&pch->file.xq);
2150 if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2151 /* put the packet back and try again later */
2152 skb_queue_head(&pch->file.xq, skb);
2153 break;
2154 }
2155 }
2156 } else {
2157 /* channel got deregistered */
2158 skb_queue_purge(&pch->file.xq);
2159 }
2160 spin_unlock(&pch->downl);
2161 /* see if there is anything from the attached unit to be sent */
2162 if (skb_queue_empty(&pch->file.xq)) {
2163 ppp = pch->ppp;
2164 if (ppp)
2165 __ppp_xmit_process(ppp, NULL);
2166 }
2167 }
2168
ppp_channel_push(struct channel * pch)2169 static void ppp_channel_push(struct channel *pch)
2170 {
2171 read_lock_bh(&pch->upl);
2172 if (pch->ppp) {
2173 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2174 __ppp_channel_push(pch);
2175 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2176 } else {
2177 __ppp_channel_push(pch);
2178 }
2179 read_unlock_bh(&pch->upl);
2180 }
2181
2182 /*
2183 * Receive-side routines.
2184 */
2185
2186 struct ppp_mp_skb_parm {
2187 u32 sequence;
2188 u8 BEbits;
2189 };
2190 #define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
2191
2192 static inline void
ppp_do_recv(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2193 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2194 {
2195 ppp_recv_lock(ppp);
2196 if (!ppp->closing)
2197 ppp_receive_frame(ppp, skb, pch);
2198 else
2199 kfree_skb(skb);
2200 ppp_recv_unlock(ppp);
2201 }
2202
2203 /**
2204 * __ppp_decompress_proto - Decompress protocol field, slim version.
2205 * @skb: Socket buffer where protocol field should be decompressed. It must have
2206 * at least 1 byte of head room and 1 byte of linear data. First byte of
2207 * data must be a protocol field byte.
2208 *
2209 * Decompress protocol field in PPP header if it's compressed, e.g. when
2210 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2211 * length are done in this function.
2212 */
__ppp_decompress_proto(struct sk_buff * skb)2213 static void __ppp_decompress_proto(struct sk_buff *skb)
2214 {
2215 if (skb->data[0] & 0x01)
2216 *(u8 *)skb_push(skb, 1) = 0x00;
2217 }
2218
2219 /**
2220 * ppp_decompress_proto - Check skb data room and decompress protocol field.
2221 * @skb: Socket buffer where protocol field should be decompressed. First byte
2222 * of data must be a protocol field byte.
2223 *
2224 * Decompress protocol field in PPP header if it's compressed, e.g. when
2225 * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2226 * sure that skb data room is sufficient for Protocol field, before and after
2227 * decompression.
2228 *
2229 * Return: true - decompressed successfully, false - not enough room in skb.
2230 */
ppp_decompress_proto(struct sk_buff * skb)2231 static bool ppp_decompress_proto(struct sk_buff *skb)
2232 {
2233 /* At least one byte should be present (if protocol is compressed) */
2234 if (!pskb_may_pull(skb, 1))
2235 return false;
2236
2237 __ppp_decompress_proto(skb);
2238
2239 /* Protocol field should occupy 2 bytes when not compressed */
2240 return pskb_may_pull(skb, 2);
2241 }
2242
2243 /* Attempt to handle a frame via. a bridged channel, if one exists.
2244 * If the channel is bridged, the frame is consumed by the bridge.
2245 * If not, the caller must handle the frame by normal recv mechanisms.
2246 * Returns true if the frame is consumed, false otherwise.
2247 */
ppp_channel_bridge_input(struct channel * pch,struct sk_buff * skb)2248 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2249 {
2250 struct channel *pchb;
2251
2252 rcu_read_lock();
2253 pchb = rcu_dereference(pch->bridge);
2254 if (!pchb)
2255 goto out_rcu;
2256
2257 spin_lock(&pchb->downl);
2258 if (!pchb->chan) {
2259 /* channel got unregistered */
2260 kfree_skb(skb);
2261 goto outl;
2262 }
2263
2264 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2265 if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2266 kfree_skb(skb);
2267
2268 outl:
2269 spin_unlock(&pchb->downl);
2270 out_rcu:
2271 rcu_read_unlock();
2272
2273 /* If pchb is set then we've consumed the packet */
2274 return !!pchb;
2275 }
2276
2277 void
ppp_input(struct ppp_channel * chan,struct sk_buff * skb)2278 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2279 {
2280 struct channel *pch = chan->ppp;
2281 int proto;
2282
2283 if (!pch) {
2284 kfree_skb(skb);
2285 return;
2286 }
2287
2288 /* If the channel is bridged, transmit via. bridge */
2289 if (ppp_channel_bridge_input(pch, skb))
2290 return;
2291
2292 read_lock_bh(&pch->upl);
2293 if (!ppp_decompress_proto(skb)) {
2294 kfree_skb(skb);
2295 if (pch->ppp) {
2296 ++pch->ppp->dev->stats.rx_length_errors;
2297 ppp_receive_error(pch->ppp);
2298 }
2299 goto done;
2300 }
2301
2302 proto = PPP_PROTO(skb);
2303 if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2304 /* put it on the channel queue */
2305 skb_queue_tail(&pch->file.rq, skb);
2306 /* drop old frames if queue too long */
2307 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2308 (skb = skb_dequeue(&pch->file.rq)))
2309 kfree_skb(skb);
2310 wake_up_interruptible(&pch->file.rwait);
2311 } else {
2312 ppp_do_recv(pch->ppp, skb, pch);
2313 }
2314
2315 done:
2316 read_unlock_bh(&pch->upl);
2317 }
2318
2319 /* Put a 0-length skb in the receive queue as an error indication */
2320 void
ppp_input_error(struct ppp_channel * chan,int code)2321 ppp_input_error(struct ppp_channel *chan, int code)
2322 {
2323 struct channel *pch = chan->ppp;
2324 struct sk_buff *skb;
2325
2326 if (!pch)
2327 return;
2328
2329 read_lock_bh(&pch->upl);
2330 if (pch->ppp) {
2331 skb = alloc_skb(0, GFP_ATOMIC);
2332 if (skb) {
2333 skb->len = 0; /* probably unnecessary */
2334 skb->cb[0] = code;
2335 ppp_do_recv(pch->ppp, skb, pch);
2336 }
2337 }
2338 read_unlock_bh(&pch->upl);
2339 }
2340
2341 /*
2342 * We come in here to process a received frame.
2343 * The receive side of the ppp unit is locked.
2344 */
2345 static void
ppp_receive_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2346 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2347 {
2348 /* note: a 0-length skb is used as an error indication */
2349 if (skb->len > 0) {
2350 skb_checksum_complete_unset(skb);
2351 #ifdef CONFIG_PPP_MULTILINK
2352 /* XXX do channel-level decompression here */
2353 if (PPP_PROTO(skb) == PPP_MP)
2354 ppp_receive_mp_frame(ppp, skb, pch);
2355 else
2356 #endif /* CONFIG_PPP_MULTILINK */
2357 ppp_receive_nonmp_frame(ppp, skb);
2358 } else {
2359 kfree_skb(skb);
2360 ppp_receive_error(ppp);
2361 }
2362 }
2363
2364 static void
ppp_receive_error(struct ppp * ppp)2365 ppp_receive_error(struct ppp *ppp)
2366 {
2367 ++ppp->dev->stats.rx_errors;
2368 if (ppp->vj)
2369 slhc_toss(ppp->vj);
2370 }
2371
2372 static void
ppp_receive_nonmp_frame(struct ppp * ppp,struct sk_buff * skb)2373 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2374 {
2375 struct sk_buff *ns;
2376 int proto, len, npi;
2377
2378 /*
2379 * Decompress the frame, if compressed.
2380 * Note that some decompressors need to see uncompressed frames
2381 * that come in as well as compressed frames.
2382 */
2383 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2384 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2385 skb = ppp_decompress_frame(ppp, skb);
2386
2387 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2388 goto err;
2389
2390 /* At this point the "Protocol" field MUST be decompressed, either in
2391 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2392 */
2393 proto = PPP_PROTO(skb);
2394 switch (proto) {
2395 case PPP_VJC_COMP:
2396 /* decompress VJ compressed packets */
2397 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2398 goto err;
2399
2400 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2401 /* copy to a new sk_buff with more tailroom */
2402 ns = dev_alloc_skb(skb->len + 128);
2403 if (!ns) {
2404 netdev_err(ppp->dev, "PPP: no memory "
2405 "(VJ decomp)\n");
2406 goto err;
2407 }
2408 skb_reserve(ns, 2);
2409 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2410 consume_skb(skb);
2411 skb = ns;
2412 }
2413 else
2414 skb->ip_summed = CHECKSUM_NONE;
2415
2416 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2417 if (len <= 0) {
2418 netdev_printk(KERN_DEBUG, ppp->dev,
2419 "PPP: VJ decompression error\n");
2420 goto err;
2421 }
2422 len += 2;
2423 if (len > skb->len)
2424 skb_put(skb, len - skb->len);
2425 else if (len < skb->len)
2426 skb_trim(skb, len);
2427 proto = PPP_IP;
2428 break;
2429
2430 case PPP_VJC_UNCOMP:
2431 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2432 goto err;
2433
2434 /* Until we fix the decompressor need to make sure
2435 * data portion is linear.
2436 */
2437 if (!pskb_may_pull(skb, skb->len))
2438 goto err;
2439
2440 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2441 netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2442 goto err;
2443 }
2444 proto = PPP_IP;
2445 break;
2446
2447 case PPP_CCP:
2448 ppp_ccp_peek(ppp, skb, 1);
2449 break;
2450 }
2451
2452 ++ppp->stats64.rx_packets;
2453 ppp->stats64.rx_bytes += skb->len - 2;
2454
2455 npi = proto_to_npindex(proto);
2456 if (npi < 0) {
2457 /* control or unknown frame - pass it to pppd */
2458 skb_queue_tail(&ppp->file.rq, skb);
2459 /* limit queue length by dropping old frames */
2460 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2461 (skb = skb_dequeue(&ppp->file.rq)))
2462 kfree_skb(skb);
2463 /* wake up any process polling or blocking on read */
2464 wake_up_interruptible(&ppp->file.rwait);
2465
2466 } else {
2467 /* network protocol frame - give it to the kernel */
2468
2469 #ifdef CONFIG_PPP_FILTER
2470 /* check if the packet passes the pass and active filters */
2471 /* the filter instructions are constructed assuming
2472 a four-byte PPP header on each packet */
2473 if (ppp->pass_filter || ppp->active_filter) {
2474 if (skb_unclone(skb, GFP_ATOMIC))
2475 goto err;
2476
2477 *(u8 *)skb_push(skb, 2) = 0;
2478 if (ppp->pass_filter &&
2479 bpf_prog_run(ppp->pass_filter, skb) == 0) {
2480 if (ppp->debug & 1)
2481 netdev_printk(KERN_DEBUG, ppp->dev,
2482 "PPP: inbound frame "
2483 "not passed\n");
2484 kfree_skb(skb);
2485 return;
2486 }
2487 if (!(ppp->active_filter &&
2488 bpf_prog_run(ppp->active_filter, skb) == 0))
2489 ppp->last_recv = jiffies;
2490 __skb_pull(skb, 2);
2491 } else
2492 #endif /* CONFIG_PPP_FILTER */
2493 ppp->last_recv = jiffies;
2494
2495 if ((ppp->dev->flags & IFF_UP) == 0 ||
2496 ppp->npmode[npi] != NPMODE_PASS) {
2497 kfree_skb(skb);
2498 } else {
2499 /* chop off protocol */
2500 skb_pull_rcsum(skb, 2);
2501 skb->dev = ppp->dev;
2502 skb->protocol = htons(npindex_to_ethertype[npi]);
2503 skb_reset_mac_header(skb);
2504 skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2505 dev_net(ppp->dev)));
2506 netif_rx(skb);
2507 }
2508 }
2509 return;
2510
2511 err:
2512 kfree_skb(skb);
2513 ppp_receive_error(ppp);
2514 }
2515
2516 static struct sk_buff *
ppp_decompress_frame(struct ppp * ppp,struct sk_buff * skb)2517 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2518 {
2519 int proto = PPP_PROTO(skb);
2520 struct sk_buff *ns;
2521 int len;
2522
2523 /* Until we fix all the decompressor's need to make sure
2524 * data portion is linear.
2525 */
2526 if (!pskb_may_pull(skb, skb->len))
2527 goto err;
2528
2529 if (proto == PPP_COMP) {
2530 int obuff_size;
2531
2532 switch(ppp->rcomp->compress_proto) {
2533 case CI_MPPE:
2534 obuff_size = ppp->mru + PPP_HDRLEN + 1;
2535 break;
2536 default:
2537 obuff_size = ppp->mru + PPP_HDRLEN;
2538 break;
2539 }
2540
2541 ns = dev_alloc_skb(obuff_size);
2542 if (!ns) {
2543 netdev_err(ppp->dev, "ppp_decompress_frame: "
2544 "no memory\n");
2545 goto err;
2546 }
2547 /* the decompressor still expects the A/C bytes in the hdr */
2548 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2549 skb->len + 2, ns->data, obuff_size);
2550 if (len < 0) {
2551 /* Pass the compressed frame to pppd as an
2552 error indication. */
2553 if (len == DECOMP_FATALERROR)
2554 ppp->rstate |= SC_DC_FERROR;
2555 kfree_skb(ns);
2556 goto err;
2557 }
2558
2559 consume_skb(skb);
2560 skb = ns;
2561 skb_put(skb, len);
2562 skb_pull(skb, 2); /* pull off the A/C bytes */
2563
2564 /* Don't call __ppp_decompress_proto() here, but instead rely on
2565 * corresponding algo (mppe/bsd/deflate) to decompress it.
2566 */
2567 } else {
2568 /* Uncompressed frame - pass to decompressor so it
2569 can update its dictionary if necessary. */
2570 if (ppp->rcomp->incomp)
2571 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2572 skb->len + 2);
2573 }
2574
2575 return skb;
2576
2577 err:
2578 ppp->rstate |= SC_DC_ERROR;
2579 ppp_receive_error(ppp);
2580 return skb;
2581 }
2582
2583 #ifdef CONFIG_PPP_MULTILINK
2584 /*
2585 * Receive a multilink frame.
2586 * We put it on the reconstruction queue and then pull off
2587 * as many completed frames as we can.
2588 */
2589 static void
ppp_receive_mp_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2590 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2591 {
2592 u32 mask, seq;
2593 struct channel *ch;
2594 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2595
2596 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2597 goto err; /* no good, throw it away */
2598
2599 /* Decode sequence number and begin/end bits */
2600 if (ppp->flags & SC_MP_SHORTSEQ) {
2601 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2602 mask = 0xfff;
2603 } else {
2604 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2605 mask = 0xffffff;
2606 }
2607 PPP_MP_CB(skb)->BEbits = skb->data[2];
2608 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */
2609
2610 /*
2611 * Do protocol ID decompression on the first fragment of each packet.
2612 * We have to do that here, because ppp_receive_nonmp_frame() expects
2613 * decompressed protocol field.
2614 */
2615 if (PPP_MP_CB(skb)->BEbits & B)
2616 __ppp_decompress_proto(skb);
2617
2618 /*
2619 * Expand sequence number to 32 bits, making it as close
2620 * as possible to ppp->minseq.
2621 */
2622 seq |= ppp->minseq & ~mask;
2623 if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2624 seq += mask + 1;
2625 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2626 seq -= mask + 1; /* should never happen */
2627 PPP_MP_CB(skb)->sequence = seq;
2628 pch->lastseq = seq;
2629
2630 /*
2631 * If this packet comes before the next one we were expecting,
2632 * drop it.
2633 */
2634 if (seq_before(seq, ppp->nextseq)) {
2635 kfree_skb(skb);
2636 ++ppp->dev->stats.rx_dropped;
2637 ppp_receive_error(ppp);
2638 return;
2639 }
2640
2641 /*
2642 * Reevaluate minseq, the minimum over all channels of the
2643 * last sequence number received on each channel. Because of
2644 * the increasing sequence number rule, we know that any fragment
2645 * before `minseq' which hasn't arrived is never going to arrive.
2646 * The list of channels can't change because we have the receive
2647 * side of the ppp unit locked.
2648 */
2649 list_for_each_entry(ch, &ppp->channels, clist) {
2650 if (seq_before(ch->lastseq, seq))
2651 seq = ch->lastseq;
2652 }
2653 if (seq_before(ppp->minseq, seq))
2654 ppp->minseq = seq;
2655
2656 /* Put the fragment on the reconstruction queue */
2657 ppp_mp_insert(ppp, skb);
2658
2659 /* If the queue is getting long, don't wait any longer for packets
2660 before the start of the queue. */
2661 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2662 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2663 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2664 ppp->minseq = PPP_MP_CB(mskb)->sequence;
2665 }
2666
2667 /* Pull completed packets off the queue and receive them. */
2668 while ((skb = ppp_mp_reconstruct(ppp))) {
2669 if (pskb_may_pull(skb, 2))
2670 ppp_receive_nonmp_frame(ppp, skb);
2671 else {
2672 ++ppp->dev->stats.rx_length_errors;
2673 kfree_skb(skb);
2674 ppp_receive_error(ppp);
2675 }
2676 }
2677
2678 return;
2679
2680 err:
2681 kfree_skb(skb);
2682 ppp_receive_error(ppp);
2683 }
2684
2685 /*
2686 * Insert a fragment on the MP reconstruction queue.
2687 * The queue is ordered by increasing sequence number.
2688 */
2689 static void
ppp_mp_insert(struct ppp * ppp,struct sk_buff * skb)2690 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2691 {
2692 struct sk_buff *p;
2693 struct sk_buff_head *list = &ppp->mrq;
2694 u32 seq = PPP_MP_CB(skb)->sequence;
2695
2696 /* N.B. we don't need to lock the list lock because we have the
2697 ppp unit receive-side lock. */
2698 skb_queue_walk(list, p) {
2699 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2700 break;
2701 }
2702 __skb_queue_before(list, p, skb);
2703 }
2704
2705 /*
2706 * Reconstruct a packet from the MP fragment queue.
2707 * We go through increasing sequence numbers until we find a
2708 * complete packet, or we get to the sequence number for a fragment
2709 * which hasn't arrived but might still do so.
2710 */
2711 static struct sk_buff *
ppp_mp_reconstruct(struct ppp * ppp)2712 ppp_mp_reconstruct(struct ppp *ppp)
2713 {
2714 u32 seq = ppp->nextseq;
2715 u32 minseq = ppp->minseq;
2716 struct sk_buff_head *list = &ppp->mrq;
2717 struct sk_buff *p, *tmp;
2718 struct sk_buff *head, *tail;
2719 struct sk_buff *skb = NULL;
2720 int lost = 0, len = 0;
2721
2722 if (ppp->mrru == 0) /* do nothing until mrru is set */
2723 return NULL;
2724 head = __skb_peek(list);
2725 tail = NULL;
2726 skb_queue_walk_safe(list, p, tmp) {
2727 again:
2728 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2729 /* this can't happen, anyway ignore the skb */
2730 netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2731 "seq %u < %u\n",
2732 PPP_MP_CB(p)->sequence, seq);
2733 __skb_unlink(p, list);
2734 kfree_skb(p);
2735 continue;
2736 }
2737 if (PPP_MP_CB(p)->sequence != seq) {
2738 u32 oldseq;
2739 /* Fragment `seq' is missing. If it is after
2740 minseq, it might arrive later, so stop here. */
2741 if (seq_after(seq, minseq))
2742 break;
2743 /* Fragment `seq' is lost, keep going. */
2744 lost = 1;
2745 oldseq = seq;
2746 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2747 minseq + 1: PPP_MP_CB(p)->sequence;
2748
2749 if (ppp->debug & 1)
2750 netdev_printk(KERN_DEBUG, ppp->dev,
2751 "lost frag %u..%u\n",
2752 oldseq, seq-1);
2753
2754 goto again;
2755 }
2756
2757 /*
2758 * At this point we know that all the fragments from
2759 * ppp->nextseq to seq are either present or lost.
2760 * Also, there are no complete packets in the queue
2761 * that have no missing fragments and end before this
2762 * fragment.
2763 */
2764
2765 /* B bit set indicates this fragment starts a packet */
2766 if (PPP_MP_CB(p)->BEbits & B) {
2767 head = p;
2768 lost = 0;
2769 len = 0;
2770 }
2771
2772 len += p->len;
2773
2774 /* Got a complete packet yet? */
2775 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2776 (PPP_MP_CB(head)->BEbits & B)) {
2777 if (len > ppp->mrru + 2) {
2778 ++ppp->dev->stats.rx_length_errors;
2779 netdev_printk(KERN_DEBUG, ppp->dev,
2780 "PPP: reconstructed packet"
2781 " is too long (%d)\n", len);
2782 } else {
2783 tail = p;
2784 break;
2785 }
2786 ppp->nextseq = seq + 1;
2787 }
2788
2789 /*
2790 * If this is the ending fragment of a packet,
2791 * and we haven't found a complete valid packet yet,
2792 * we can discard up to and including this fragment.
2793 */
2794 if (PPP_MP_CB(p)->BEbits & E) {
2795 struct sk_buff *tmp2;
2796
2797 skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2798 if (ppp->debug & 1)
2799 netdev_printk(KERN_DEBUG, ppp->dev,
2800 "discarding frag %u\n",
2801 PPP_MP_CB(p)->sequence);
2802 __skb_unlink(p, list);
2803 kfree_skb(p);
2804 }
2805 head = skb_peek(list);
2806 if (!head)
2807 break;
2808 }
2809 ++seq;
2810 }
2811
2812 /* If we have a complete packet, copy it all into one skb. */
2813 if (tail != NULL) {
2814 /* If we have discarded any fragments,
2815 signal a receive error. */
2816 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2817 skb_queue_walk_safe(list, p, tmp) {
2818 if (p == head)
2819 break;
2820 if (ppp->debug & 1)
2821 netdev_printk(KERN_DEBUG, ppp->dev,
2822 "discarding frag %u\n",
2823 PPP_MP_CB(p)->sequence);
2824 __skb_unlink(p, list);
2825 kfree_skb(p);
2826 }
2827
2828 if (ppp->debug & 1)
2829 netdev_printk(KERN_DEBUG, ppp->dev,
2830 " missed pkts %u..%u\n",
2831 ppp->nextseq,
2832 PPP_MP_CB(head)->sequence-1);
2833 ++ppp->dev->stats.rx_dropped;
2834 ppp_receive_error(ppp);
2835 }
2836
2837 skb = head;
2838 if (head != tail) {
2839 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2840 p = skb_queue_next(list, head);
2841 __skb_unlink(skb, list);
2842 skb_queue_walk_from_safe(list, p, tmp) {
2843 __skb_unlink(p, list);
2844 *fragpp = p;
2845 p->next = NULL;
2846 fragpp = &p->next;
2847
2848 skb->len += p->len;
2849 skb->data_len += p->len;
2850 skb->truesize += p->truesize;
2851
2852 if (p == tail)
2853 break;
2854 }
2855 } else {
2856 __skb_unlink(skb, list);
2857 }
2858
2859 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2860 }
2861
2862 return skb;
2863 }
2864 #endif /* CONFIG_PPP_MULTILINK */
2865
2866 /*
2867 * Channel interface.
2868 */
2869
2870 /* Create a new, unattached ppp channel. */
ppp_register_channel(struct ppp_channel * chan)2871 int ppp_register_channel(struct ppp_channel *chan)
2872 {
2873 return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2874 }
2875
2876 /* Create a new, unattached ppp channel for specified net. */
ppp_register_net_channel(struct net * net,struct ppp_channel * chan)2877 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2878 {
2879 struct channel *pch;
2880 struct ppp_net *pn;
2881
2882 pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2883 if (!pch)
2884 return -ENOMEM;
2885
2886 pn = ppp_pernet(net);
2887
2888 pch->ppp = NULL;
2889 pch->chan = chan;
2890 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2891 chan->ppp = pch;
2892 init_ppp_file(&pch->file, CHANNEL);
2893 pch->file.hdrlen = chan->hdrlen;
2894 #ifdef CONFIG_PPP_MULTILINK
2895 pch->lastseq = -1;
2896 #endif /* CONFIG_PPP_MULTILINK */
2897 init_rwsem(&pch->chan_sem);
2898 spin_lock_init(&pch->downl);
2899 rwlock_init(&pch->upl);
2900
2901 spin_lock_bh(&pn->all_channels_lock);
2902 pch->file.index = ++pn->last_channel_index;
2903 list_add(&pch->list, &pn->new_channels);
2904 atomic_inc(&channel_count);
2905 spin_unlock_bh(&pn->all_channels_lock);
2906
2907 return 0;
2908 }
2909
2910 /*
2911 * Return the index of a channel.
2912 */
ppp_channel_index(struct ppp_channel * chan)2913 int ppp_channel_index(struct ppp_channel *chan)
2914 {
2915 struct channel *pch = chan->ppp;
2916
2917 if (pch)
2918 return pch->file.index;
2919 return -1;
2920 }
2921
2922 /*
2923 * Return the PPP unit number to which a channel is connected.
2924 */
ppp_unit_number(struct ppp_channel * chan)2925 int ppp_unit_number(struct ppp_channel *chan)
2926 {
2927 struct channel *pch = chan->ppp;
2928 int unit = -1;
2929
2930 if (pch) {
2931 read_lock_bh(&pch->upl);
2932 if (pch->ppp)
2933 unit = pch->ppp->file.index;
2934 read_unlock_bh(&pch->upl);
2935 }
2936 return unit;
2937 }
2938
2939 /*
2940 * Return the PPP device interface name of a channel.
2941 */
ppp_dev_name(struct ppp_channel * chan)2942 char *ppp_dev_name(struct ppp_channel *chan)
2943 {
2944 struct channel *pch = chan->ppp;
2945 char *name = NULL;
2946
2947 if (pch) {
2948 read_lock_bh(&pch->upl);
2949 if (pch->ppp && pch->ppp->dev)
2950 name = pch->ppp->dev->name;
2951 read_unlock_bh(&pch->upl);
2952 }
2953 return name;
2954 }
2955
2956
2957 /*
2958 * Disconnect a channel from the generic layer.
2959 * This must be called in process context.
2960 */
2961 void
ppp_unregister_channel(struct ppp_channel * chan)2962 ppp_unregister_channel(struct ppp_channel *chan)
2963 {
2964 struct channel *pch = chan->ppp;
2965 struct ppp_net *pn;
2966
2967 if (!pch)
2968 return; /* should never happen */
2969
2970 chan->ppp = NULL;
2971
2972 /*
2973 * This ensures that we have returned from any calls into
2974 * the channel's start_xmit or ioctl routine before we proceed.
2975 */
2976 down_write(&pch->chan_sem);
2977 spin_lock_bh(&pch->downl);
2978 pch->chan = NULL;
2979 spin_unlock_bh(&pch->downl);
2980 up_write(&pch->chan_sem);
2981 ppp_disconnect_channel(pch);
2982
2983 pn = ppp_pernet(pch->chan_net);
2984 spin_lock_bh(&pn->all_channels_lock);
2985 list_del(&pch->list);
2986 spin_unlock_bh(&pn->all_channels_lock);
2987
2988 ppp_unbridge_channels(pch);
2989
2990 pch->file.dead = 1;
2991 wake_up_interruptible(&pch->file.rwait);
2992
2993 if (refcount_dec_and_test(&pch->file.refcnt))
2994 ppp_destroy_channel(pch);
2995 }
2996
2997 /*
2998 * Callback from a channel when it can accept more to transmit.
2999 * This should be called at BH/softirq level, not interrupt level.
3000 */
3001 void
ppp_output_wakeup(struct ppp_channel * chan)3002 ppp_output_wakeup(struct ppp_channel *chan)
3003 {
3004 struct channel *pch = chan->ppp;
3005
3006 if (!pch)
3007 return;
3008 ppp_channel_push(pch);
3009 }
3010
3011 /*
3012 * Compression control.
3013 */
3014
3015 /* Process the PPPIOCSCOMPRESS ioctl. */
3016 static int
ppp_set_compress(struct ppp * ppp,struct ppp_option_data * data)3017 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3018 {
3019 int err = -EFAULT;
3020 struct compressor *cp, *ocomp;
3021 void *state, *ostate;
3022 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3023
3024 if (data->length > CCP_MAX_OPTION_LENGTH)
3025 goto out;
3026 if (copy_from_user(ccp_option, data->ptr, data->length))
3027 goto out;
3028
3029 err = -EINVAL;
3030 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3031 goto out;
3032
3033 cp = try_then_request_module(
3034 find_compressor(ccp_option[0]),
3035 "ppp-compress-%d", ccp_option[0]);
3036 if (!cp)
3037 goto out;
3038
3039 err = -ENOBUFS;
3040 if (data->transmit) {
3041 state = cp->comp_alloc(ccp_option, data->length);
3042 if (state) {
3043 ppp_xmit_lock(ppp);
3044 ppp->xstate &= ~SC_COMP_RUN;
3045 ocomp = ppp->xcomp;
3046 ostate = ppp->xc_state;
3047 ppp->xcomp = cp;
3048 ppp->xc_state = state;
3049 ppp_xmit_unlock(ppp);
3050 if (ostate) {
3051 ocomp->comp_free(ostate);
3052 module_put(ocomp->owner);
3053 }
3054 err = 0;
3055 } else
3056 module_put(cp->owner);
3057
3058 } else {
3059 state = cp->decomp_alloc(ccp_option, data->length);
3060 if (state) {
3061 ppp_recv_lock(ppp);
3062 ppp->rstate &= ~SC_DECOMP_RUN;
3063 ocomp = ppp->rcomp;
3064 ostate = ppp->rc_state;
3065 ppp->rcomp = cp;
3066 ppp->rc_state = state;
3067 ppp_recv_unlock(ppp);
3068 if (ostate) {
3069 ocomp->decomp_free(ostate);
3070 module_put(ocomp->owner);
3071 }
3072 err = 0;
3073 } else
3074 module_put(cp->owner);
3075 }
3076
3077 out:
3078 return err;
3079 }
3080
3081 /*
3082 * Look at a CCP packet and update our state accordingly.
3083 * We assume the caller has the xmit or recv path locked.
3084 */
3085 static void
ppp_ccp_peek(struct ppp * ppp,struct sk_buff * skb,int inbound)3086 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3087 {
3088 unsigned char *dp;
3089 int len;
3090
3091 if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3092 return; /* no header */
3093 dp = skb->data + 2;
3094
3095 switch (CCP_CODE(dp)) {
3096 case CCP_CONFREQ:
3097
3098 /* A ConfReq starts negotiation of compression
3099 * in one direction of transmission,
3100 * and hence brings it down...but which way?
3101 *
3102 * Remember:
3103 * A ConfReq indicates what the sender would like to receive
3104 */
3105 if(inbound)
3106 /* He is proposing what I should send */
3107 ppp->xstate &= ~SC_COMP_RUN;
3108 else
3109 /* I am proposing to what he should send */
3110 ppp->rstate &= ~SC_DECOMP_RUN;
3111
3112 break;
3113
3114 case CCP_TERMREQ:
3115 case CCP_TERMACK:
3116 /*
3117 * CCP is going down, both directions of transmission
3118 */
3119 ppp->rstate &= ~SC_DECOMP_RUN;
3120 ppp->xstate &= ~SC_COMP_RUN;
3121 break;
3122
3123 case CCP_CONFACK:
3124 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3125 break;
3126 len = CCP_LENGTH(dp);
3127 if (!pskb_may_pull(skb, len + 2))
3128 return; /* too short */
3129 dp += CCP_HDRLEN;
3130 len -= CCP_HDRLEN;
3131 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3132 break;
3133 if (inbound) {
3134 /* we will start receiving compressed packets */
3135 if (!ppp->rc_state)
3136 break;
3137 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3138 ppp->file.index, 0, ppp->mru, ppp->debug)) {
3139 ppp->rstate |= SC_DECOMP_RUN;
3140 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3141 }
3142 } else {
3143 /* we will soon start sending compressed packets */
3144 if (!ppp->xc_state)
3145 break;
3146 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3147 ppp->file.index, 0, ppp->debug))
3148 ppp->xstate |= SC_COMP_RUN;
3149 }
3150 break;
3151
3152 case CCP_RESETACK:
3153 /* reset the [de]compressor */
3154 if ((ppp->flags & SC_CCP_UP) == 0)
3155 break;
3156 if (inbound) {
3157 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3158 ppp->rcomp->decomp_reset(ppp->rc_state);
3159 ppp->rstate &= ~SC_DC_ERROR;
3160 }
3161 } else {
3162 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3163 ppp->xcomp->comp_reset(ppp->xc_state);
3164 }
3165 break;
3166 }
3167 }
3168
3169 /* Free up compression resources. */
3170 static void
ppp_ccp_closed(struct ppp * ppp)3171 ppp_ccp_closed(struct ppp *ppp)
3172 {
3173 void *xstate, *rstate;
3174 struct compressor *xcomp, *rcomp;
3175
3176 ppp_lock(ppp);
3177 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3178 ppp->xstate = 0;
3179 xcomp = ppp->xcomp;
3180 xstate = ppp->xc_state;
3181 ppp->xc_state = NULL;
3182 ppp->rstate = 0;
3183 rcomp = ppp->rcomp;
3184 rstate = ppp->rc_state;
3185 ppp->rc_state = NULL;
3186 ppp_unlock(ppp);
3187
3188 if (xstate) {
3189 xcomp->comp_free(xstate);
3190 module_put(xcomp->owner);
3191 }
3192 if (rstate) {
3193 rcomp->decomp_free(rstate);
3194 module_put(rcomp->owner);
3195 }
3196 }
3197
3198 /* List of compressors. */
3199 static LIST_HEAD(compressor_list);
3200 static DEFINE_SPINLOCK(compressor_list_lock);
3201
3202 struct compressor_entry {
3203 struct list_head list;
3204 struct compressor *comp;
3205 };
3206
3207 static struct compressor_entry *
find_comp_entry(int proto)3208 find_comp_entry(int proto)
3209 {
3210 struct compressor_entry *ce;
3211
3212 list_for_each_entry(ce, &compressor_list, list) {
3213 if (ce->comp->compress_proto == proto)
3214 return ce;
3215 }
3216 return NULL;
3217 }
3218
3219 /* Register a compressor */
3220 int
ppp_register_compressor(struct compressor * cp)3221 ppp_register_compressor(struct compressor *cp)
3222 {
3223 struct compressor_entry *ce;
3224 int ret;
3225 spin_lock(&compressor_list_lock);
3226 ret = -EEXIST;
3227 if (find_comp_entry(cp->compress_proto))
3228 goto out;
3229 ret = -ENOMEM;
3230 ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3231 if (!ce)
3232 goto out;
3233 ret = 0;
3234 ce->comp = cp;
3235 list_add(&ce->list, &compressor_list);
3236 out:
3237 spin_unlock(&compressor_list_lock);
3238 return ret;
3239 }
3240
3241 /* Unregister a compressor */
3242 void
ppp_unregister_compressor(struct compressor * cp)3243 ppp_unregister_compressor(struct compressor *cp)
3244 {
3245 struct compressor_entry *ce;
3246
3247 spin_lock(&compressor_list_lock);
3248 ce = find_comp_entry(cp->compress_proto);
3249 if (ce && ce->comp == cp) {
3250 list_del(&ce->list);
3251 kfree(ce);
3252 }
3253 spin_unlock(&compressor_list_lock);
3254 }
3255
3256 /* Find a compressor. */
3257 static struct compressor *
find_compressor(int type)3258 find_compressor(int type)
3259 {
3260 struct compressor_entry *ce;
3261 struct compressor *cp = NULL;
3262
3263 spin_lock(&compressor_list_lock);
3264 ce = find_comp_entry(type);
3265 if (ce) {
3266 cp = ce->comp;
3267 if (!try_module_get(cp->owner))
3268 cp = NULL;
3269 }
3270 spin_unlock(&compressor_list_lock);
3271 return cp;
3272 }
3273
3274 /*
3275 * Miscelleneous stuff.
3276 */
3277
3278 static void
ppp_get_stats(struct ppp * ppp,struct ppp_stats * st)3279 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3280 {
3281 struct slcompress *vj = ppp->vj;
3282
3283 memset(st, 0, sizeof(*st));
3284 st->p.ppp_ipackets = ppp->stats64.rx_packets;
3285 st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3286 st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3287 st->p.ppp_opackets = ppp->stats64.tx_packets;
3288 st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3289 st->p.ppp_obytes = ppp->stats64.tx_bytes;
3290 if (!vj)
3291 return;
3292 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3293 st->vj.vjs_compressed = vj->sls_o_compressed;
3294 st->vj.vjs_searches = vj->sls_o_searches;
3295 st->vj.vjs_misses = vj->sls_o_misses;
3296 st->vj.vjs_errorin = vj->sls_i_error;
3297 st->vj.vjs_tossed = vj->sls_i_tossed;
3298 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3299 st->vj.vjs_compressedin = vj->sls_i_compressed;
3300 }
3301
3302 /*
3303 * Stuff for handling the lists of ppp units and channels
3304 * and for initialization.
3305 */
3306
3307 /*
3308 * Create a new ppp interface unit. Fails if it can't allocate memory
3309 * or if there is already a unit with the requested number.
3310 * unit == -1 means allocate a new number.
3311 */
ppp_create_interface(struct net * net,struct file * file,int * unit)3312 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3313 {
3314 struct ppp_config conf = {
3315 .file = file,
3316 .unit = *unit,
3317 .ifname_is_set = false,
3318 };
3319 struct net_device *dev;
3320 struct ppp *ppp;
3321 int err;
3322
3323 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3324 if (!dev) {
3325 err = -ENOMEM;
3326 goto err;
3327 }
3328 dev_net_set(dev, net);
3329 dev->rtnl_link_ops = &ppp_link_ops;
3330
3331 rtnl_lock();
3332
3333 err = ppp_dev_configure(net, dev, &conf);
3334 if (err < 0)
3335 goto err_dev;
3336 ppp = netdev_priv(dev);
3337 *unit = ppp->file.index;
3338
3339 rtnl_unlock();
3340
3341 return 0;
3342
3343 err_dev:
3344 rtnl_unlock();
3345 free_netdev(dev);
3346 err:
3347 return err;
3348 }
3349
3350 /*
3351 * Initialize a ppp_file structure.
3352 */
3353 static void
init_ppp_file(struct ppp_file * pf,int kind)3354 init_ppp_file(struct ppp_file *pf, int kind)
3355 {
3356 pf->kind = kind;
3357 skb_queue_head_init(&pf->xq);
3358 skb_queue_head_init(&pf->rq);
3359 refcount_set(&pf->refcnt, 1);
3360 init_waitqueue_head(&pf->rwait);
3361 }
3362
3363 /*
3364 * Free the memory used by a ppp unit. This is only called once
3365 * there are no channels connected to the unit and no file structs
3366 * that reference the unit.
3367 */
ppp_destroy_interface(struct ppp * ppp)3368 static void ppp_destroy_interface(struct ppp *ppp)
3369 {
3370 atomic_dec(&ppp_unit_count);
3371
3372 if (!ppp->file.dead || ppp->n_channels) {
3373 /* "can't happen" */
3374 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3375 "but dead=%d n_channels=%d !\n",
3376 ppp, ppp->file.dead, ppp->n_channels);
3377 return;
3378 }
3379
3380 ppp_ccp_closed(ppp);
3381 if (ppp->vj) {
3382 slhc_free(ppp->vj);
3383 ppp->vj = NULL;
3384 }
3385 skb_queue_purge(&ppp->file.xq);
3386 skb_queue_purge(&ppp->file.rq);
3387 #ifdef CONFIG_PPP_MULTILINK
3388 skb_queue_purge(&ppp->mrq);
3389 #endif /* CONFIG_PPP_MULTILINK */
3390 #ifdef CONFIG_PPP_FILTER
3391 if (ppp->pass_filter) {
3392 bpf_prog_destroy(ppp->pass_filter);
3393 ppp->pass_filter = NULL;
3394 }
3395
3396 if (ppp->active_filter) {
3397 bpf_prog_destroy(ppp->active_filter);
3398 ppp->active_filter = NULL;
3399 }
3400 #endif /* CONFIG_PPP_FILTER */
3401
3402 kfree_skb(ppp->xmit_pending);
3403 free_percpu(ppp->xmit_recursion);
3404
3405 free_netdev(ppp->dev);
3406 }
3407
3408 /*
3409 * Locate an existing ppp unit.
3410 * The caller should have locked the all_ppp_mutex.
3411 */
3412 static struct ppp *
ppp_find_unit(struct ppp_net * pn,int unit)3413 ppp_find_unit(struct ppp_net *pn, int unit)
3414 {
3415 return unit_find(&pn->units_idr, unit);
3416 }
3417
3418 /*
3419 * Locate an existing ppp channel.
3420 * The caller should have locked the all_channels_lock.
3421 * First we look in the new_channels list, then in the
3422 * all_channels list. If found in the new_channels list,
3423 * we move it to the all_channels list. This is for speed
3424 * when we have a lot of channels in use.
3425 */
3426 static struct channel *
ppp_find_channel(struct ppp_net * pn,int unit)3427 ppp_find_channel(struct ppp_net *pn, int unit)
3428 {
3429 struct channel *pch;
3430
3431 list_for_each_entry(pch, &pn->new_channels, list) {
3432 if (pch->file.index == unit) {
3433 list_move(&pch->list, &pn->all_channels);
3434 return pch;
3435 }
3436 }
3437
3438 list_for_each_entry(pch, &pn->all_channels, list) {
3439 if (pch->file.index == unit)
3440 return pch;
3441 }
3442
3443 return NULL;
3444 }
3445
3446 /*
3447 * Connect a PPP channel to a PPP interface unit.
3448 */
3449 static int
ppp_connect_channel(struct channel * pch,int unit)3450 ppp_connect_channel(struct channel *pch, int unit)
3451 {
3452 struct ppp *ppp;
3453 struct ppp_net *pn;
3454 int ret = -ENXIO;
3455 int hdrlen;
3456
3457 pn = ppp_pernet(pch->chan_net);
3458
3459 mutex_lock(&pn->all_ppp_mutex);
3460 ppp = ppp_find_unit(pn, unit);
3461 if (!ppp)
3462 goto out;
3463 write_lock_bh(&pch->upl);
3464 ret = -EINVAL;
3465 if (pch->ppp ||
3466 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3467 goto outl;
3468
3469 ppp_lock(ppp);
3470 spin_lock_bh(&pch->downl);
3471 if (!pch->chan) {
3472 /* Don't connect unregistered channels */
3473 spin_unlock_bh(&pch->downl);
3474 ppp_unlock(ppp);
3475 ret = -ENOTCONN;
3476 goto outl;
3477 }
3478 spin_unlock_bh(&pch->downl);
3479 if (pch->file.hdrlen > ppp->file.hdrlen)
3480 ppp->file.hdrlen = pch->file.hdrlen;
3481 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
3482 if (hdrlen > ppp->dev->hard_header_len)
3483 ppp->dev->hard_header_len = hdrlen;
3484 list_add_tail(&pch->clist, &ppp->channels);
3485 ++ppp->n_channels;
3486 pch->ppp = ppp;
3487 refcount_inc(&ppp->file.refcnt);
3488 ppp_unlock(ppp);
3489 ret = 0;
3490
3491 outl:
3492 write_unlock_bh(&pch->upl);
3493 out:
3494 mutex_unlock(&pn->all_ppp_mutex);
3495 return ret;
3496 }
3497
3498 /*
3499 * Disconnect a channel from its ppp unit.
3500 */
3501 static int
ppp_disconnect_channel(struct channel * pch)3502 ppp_disconnect_channel(struct channel *pch)
3503 {
3504 struct ppp *ppp;
3505 int err = -EINVAL;
3506
3507 write_lock_bh(&pch->upl);
3508 ppp = pch->ppp;
3509 pch->ppp = NULL;
3510 write_unlock_bh(&pch->upl);
3511 if (ppp) {
3512 /* remove it from the ppp unit's list */
3513 ppp_lock(ppp);
3514 list_del(&pch->clist);
3515 if (--ppp->n_channels == 0)
3516 wake_up_interruptible(&ppp->file.rwait);
3517 ppp_unlock(ppp);
3518 if (refcount_dec_and_test(&ppp->file.refcnt))
3519 ppp_destroy_interface(ppp);
3520 err = 0;
3521 }
3522 return err;
3523 }
3524
3525 /*
3526 * Free up the resources used by a ppp channel.
3527 */
ppp_destroy_channel(struct channel * pch)3528 static void ppp_destroy_channel(struct channel *pch)
3529 {
3530 put_net_track(pch->chan_net, &pch->ns_tracker);
3531 pch->chan_net = NULL;
3532
3533 atomic_dec(&channel_count);
3534
3535 if (!pch->file.dead) {
3536 /* "can't happen" */
3537 pr_err("ppp: destroying undead channel %p !\n", pch);
3538 return;
3539 }
3540 skb_queue_purge(&pch->file.xq);
3541 skb_queue_purge(&pch->file.rq);
3542 kfree(pch);
3543 }
3544
ppp_cleanup(void)3545 static void __exit ppp_cleanup(void)
3546 {
3547 /* should never happen */
3548 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3549 pr_err("PPP: removing module but units remain!\n");
3550 rtnl_link_unregister(&ppp_link_ops);
3551 unregister_chrdev(PPP_MAJOR, "ppp");
3552 device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3553 class_destroy(ppp_class);
3554 unregister_pernet_device(&ppp_net_ops);
3555 }
3556
3557 /*
3558 * Units handling. Caller must protect concurrent access
3559 * by holding all_ppp_mutex
3560 */
3561
3562 /* associate pointer with specified number */
unit_set(struct idr * p,void * ptr,int n)3563 static int unit_set(struct idr *p, void *ptr, int n)
3564 {
3565 int unit;
3566
3567 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3568 if (unit == -ENOSPC)
3569 unit = -EINVAL;
3570 return unit;
3571 }
3572
3573 /* get new free unit number and associate pointer with it */
unit_get(struct idr * p,void * ptr,int min)3574 static int unit_get(struct idr *p, void *ptr, int min)
3575 {
3576 return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3577 }
3578
3579 /* put unit number back to a pool */
unit_put(struct idr * p,int n)3580 static void unit_put(struct idr *p, int n)
3581 {
3582 idr_remove(p, n);
3583 }
3584
3585 /* get pointer associated with the number */
unit_find(struct idr * p,int n)3586 static void *unit_find(struct idr *p, int n)
3587 {
3588 return idr_find(p, n);
3589 }
3590
3591 /* Module/initialization stuff */
3592
3593 module_init(ppp_init);
3594 module_exit(ppp_cleanup);
3595
3596 EXPORT_SYMBOL(ppp_register_net_channel);
3597 EXPORT_SYMBOL(ppp_register_channel);
3598 EXPORT_SYMBOL(ppp_unregister_channel);
3599 EXPORT_SYMBOL(ppp_channel_index);
3600 EXPORT_SYMBOL(ppp_unit_number);
3601 EXPORT_SYMBOL(ppp_dev_name);
3602 EXPORT_SYMBOL(ppp_input);
3603 EXPORT_SYMBOL(ppp_input_error);
3604 EXPORT_SYMBOL(ppp_output_wakeup);
3605 EXPORT_SYMBOL(ppp_register_compressor);
3606 EXPORT_SYMBOL(ppp_unregister_compressor);
3607 MODULE_LICENSE("GPL");
3608 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3609 MODULE_ALIAS_RTNL_LINK("ppp");
3610 MODULE_ALIAS("devname:ppp");
3611