1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Generic PPP layer for Linux.
4 *
5 * Copyright 1999-2002 Paul Mackerras.
6 *
7 * The generic PPP layer handles the PPP network interfaces, the
8 * /dev/ppp device, packet and VJ compression, and multilink.
9 * It talks to PPP `channels' via the interface defined in
10 * include/linux/ppp_channel.h. Channels provide the basic means for
11 * sending and receiving PPP frames on some kind of communications
12 * channel.
13 *
14 * Part of the code in this driver was inspired by the old async-only
15 * PPP driver, written by Michael Callahan and Al Longyear, and
16 * subsequently hacked by Paul Mackerras.
17 *
18 * ==FILEVERSION 20041108==
19 */
20
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/sched/signal.h>
24 #include <linux/kmod.h>
25 #include <linux/init.h>
26 #include <linux/list.h>
27 #include <linux/idr.h>
28 #include <linux/netdevice.h>
29 #include <linux/poll.h>
30 #include <linux/ppp_defs.h>
31 #include <linux/filter.h>
32 #include <linux/ppp-ioctl.h>
33 #include <linux/ppp_channel.h>
34 #include <linux/ppp-comp.h>
35 #include <linux/skbuff.h>
36 #include <linux/rtnetlink.h>
37 #include <linux/if_arp.h>
38 #include <linux/ip.h>
39 #include <linux/tcp.h>
40 #include <linux/spinlock.h>
41 #include <linux/rwsem.h>
42 #include <linux/stddef.h>
43 #include <linux/device.h>
44 #include <linux/mutex.h>
45 #include <linux/slab.h>
46 #include <linux/file.h>
47 #include <asm/unaligned.h>
48 #include <net/slhc_vj.h>
49 #include <linux/atomic.h>
50 #include <linux/refcount.h>
51
52 #include <linux/nsproxy.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.h>
55
56 #define PPP_VERSION "2.4.2"
57
58 /*
59 * Network protocols we support.
60 */
61 #define NP_IP 0 /* Internet Protocol V4 */
62 #define NP_IPV6 1 /* Internet Protocol V6 */
63 #define NP_IPX 2 /* IPX protocol */
64 #define NP_AT 3 /* Appletalk protocol */
65 #define NP_MPLS_UC 4 /* MPLS unicast */
66 #define NP_MPLS_MC 5 /* MPLS multicast */
67 #define NUM_NP 6 /* Number of NPs. */
68
69 #define MPHDRLEN 6 /* multilink protocol header length */
70 #define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
71
72 #define PPP_PROTO_LEN 2
73 #define PPP_LCP_HDRLEN 4
74
75 /*
76 * An instance of /dev/ppp can be associated with either a ppp
77 * interface unit or a ppp channel. In both cases, file->private_data
78 * points to one of these.
79 */
80 struct ppp_file {
81 enum {
82 INTERFACE=1, CHANNEL
83 } kind;
84 struct sk_buff_head xq; /* pppd transmit queue */
85 struct sk_buff_head rq; /* receive queue for pppd */
86 wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
87 refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
88 int hdrlen; /* space to leave for headers */
89 int index; /* interface unit / channel number */
90 int dead; /* unit/channel has been shut down */
91 };
92
93 #define PF_TO_X(pf, X) container_of(pf, X, file)
94
95 #define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
96 #define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
97
98 /*
99 * Data structure to hold primary network stats for which
100 * we want to use 64 bit storage. Other network stats
101 * are stored in dev->stats of the ppp strucute.
102 */
103 struct ppp_link_stats {
104 u64 rx_packets;
105 u64 tx_packets;
106 u64 rx_bytes;
107 u64 tx_bytes;
108 };
109
110 /*
111 * Data structure describing one ppp unit.
112 * A ppp unit corresponds to a ppp network interface device
113 * and represents a multilink bundle.
114 * It can have 0 or more ppp channels connected to it.
115 */
116 struct ppp {
117 struct ppp_file file; /* stuff for read/write/poll 0 */
118 struct file *owner; /* file that owns this unit 48 */
119 struct list_head channels; /* list of attached channels 4c */
120 int n_channels; /* how many channels are attached 54 */
121 spinlock_t rlock; /* lock for receive side 58 */
122 spinlock_t wlock; /* lock for transmit side 5c */
123 int __percpu *xmit_recursion; /* xmit recursion detect */
124 int mru; /* max receive unit 60 */
125 unsigned int flags; /* control bits 64 */
126 unsigned int xstate; /* transmit state bits 68 */
127 unsigned int rstate; /* receive state bits 6c */
128 int debug; /* debug flags 70 */
129 struct slcompress *vj; /* state for VJ header compression */
130 enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
131 struct sk_buff *xmit_pending; /* a packet ready to go out 88 */
132 struct compressor *xcomp; /* transmit packet compressor 8c */
133 void *xc_state; /* its internal state 90 */
134 struct compressor *rcomp; /* receive decompressor 94 */
135 void *rc_state; /* its internal state 98 */
136 unsigned long last_xmit; /* jiffies when last pkt sent 9c */
137 unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
138 struct net_device *dev; /* network interface device a4 */
139 int closing; /* is device closing down? a8 */
140 #ifdef CONFIG_PPP_MULTILINK
141 int nxchan; /* next channel to send something on */
142 u32 nxseq; /* next sequence number to send */
143 int mrru; /* MP: max reconst. receive unit */
144 u32 nextseq; /* MP: seq no of next packet */
145 u32 minseq; /* MP: min of most recent seqnos */
146 struct sk_buff_head mrq; /* MP: receive reconstruction queue */
147 #endif /* CONFIG_PPP_MULTILINK */
148 #ifdef CONFIG_PPP_FILTER
149 struct bpf_prog *pass_filter; /* filter for packets to pass */
150 struct bpf_prog *active_filter; /* filter for pkts to reset idle */
151 #endif /* CONFIG_PPP_FILTER */
152 struct net *ppp_net; /* the net we belong to */
153 struct ppp_link_stats stats64; /* 64 bit network stats */
154 };
155
156 /*
157 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
158 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
159 * SC_MUST_COMP
160 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
161 * Bits in xstate: SC_COMP_RUN
162 */
163 #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
164 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
165 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
166
167 /*
168 * Private data structure for each channel.
169 * This includes the data structure used for multilink.
170 */
171 struct channel {
172 struct ppp_file file; /* stuff for read/write/poll */
173 struct list_head list; /* link in all/new_channels list */
174 struct ppp_channel *chan; /* public channel data structure */
175 struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */
176 spinlock_t downl; /* protects `chan', file.xq dequeue */
177 struct ppp *ppp; /* ppp unit we're connected to */
178 struct net *chan_net; /* the net channel belongs to */
179 netns_tracker ns_tracker;
180 struct list_head clist; /* link in list of channels per unit */
181 rwlock_t upl; /* protects `ppp' and 'bridge' */
182 struct channel __rcu *bridge; /* "bridged" ppp channel */
183 #ifdef CONFIG_PPP_MULTILINK
184 u8 avail; /* flag used in multilink stuff */
185 u8 had_frag; /* >= 1 fragments have been sent */
186 u32 lastseq; /* MP: last sequence # received */
187 int speed; /* speed of the corresponding ppp channel*/
188 #endif /* CONFIG_PPP_MULTILINK */
189 };
190
191 struct ppp_config {
192 struct file *file;
193 s32 unit;
194 bool ifname_is_set;
195 };
196
197 /*
198 * SMP locking issues:
199 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
200 * list and the ppp.n_channels field, you need to take both locks
201 * before you modify them.
202 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
203 * channel.downl.
204 */
205
206 static DEFINE_MUTEX(ppp_mutex);
207 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
208 static atomic_t channel_count = ATOMIC_INIT(0);
209
210 /* per-net private data for this module */
211 static unsigned int ppp_net_id __read_mostly;
212 struct ppp_net {
213 /* units to ppp mapping */
214 struct idr units_idr;
215
216 /*
217 * all_ppp_mutex protects the units_idr mapping.
218 * It also ensures that finding a ppp unit in the units_idr
219 * map and updating its file.refcnt field is atomic.
220 */
221 struct mutex all_ppp_mutex;
222
223 /* channels */
224 struct list_head all_channels;
225 struct list_head new_channels;
226 int last_channel_index;
227
228 /*
229 * all_channels_lock protects all_channels and
230 * last_channel_index, and the atomicity of find
231 * a channel and updating its file.refcnt field.
232 */
233 spinlock_t all_channels_lock;
234 };
235
236 /* Get the PPP protocol number from a skb */
237 #define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
238
239 /* We limit the length of ppp->file.rq to this (arbitrary) value */
240 #define PPP_MAX_RQLEN 32
241
242 /*
243 * Maximum number of multilink fragments queued up.
244 * This has to be large enough to cope with the maximum latency of
245 * the slowest channel relative to the others. Strictly it should
246 * depend on the number of channels and their characteristics.
247 */
248 #define PPP_MP_MAX_QLEN 128
249
250 /* Multilink header bits. */
251 #define B 0x80 /* this fragment begins a packet */
252 #define E 0x40 /* this fragment ends a packet */
253
254 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */
255 #define seq_before(a, b) ((s32)((a) - (b)) < 0)
256 #define seq_after(a, b) ((s32)((a) - (b)) > 0)
257
258 /* Prototypes. */
259 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
260 struct file *file, unsigned int cmd, unsigned long arg);
261 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
262 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
263 static void ppp_push(struct ppp *ppp);
264 static void ppp_channel_push(struct channel *pch);
265 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
266 struct channel *pch);
267 static void ppp_receive_error(struct ppp *ppp);
268 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
269 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
270 struct sk_buff *skb);
271 #ifdef CONFIG_PPP_MULTILINK
272 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
273 struct channel *pch);
274 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
275 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
276 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
277 #endif /* CONFIG_PPP_MULTILINK */
278 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
279 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
280 static void ppp_ccp_closed(struct ppp *ppp);
281 static struct compressor *find_compressor(int type);
282 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
283 static int ppp_create_interface(struct net *net, struct file *file, int *unit);
284 static void init_ppp_file(struct ppp_file *pf, int kind);
285 static void ppp_destroy_interface(struct ppp *ppp);
286 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
287 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
288 static int ppp_connect_channel(struct channel *pch, int unit);
289 static int ppp_disconnect_channel(struct channel *pch);
290 static void ppp_destroy_channel(struct channel *pch);
291 static int unit_get(struct idr *p, void *ptr, int min);
292 static int unit_set(struct idr *p, void *ptr, int n);
293 static void unit_put(struct idr *p, int n);
294 static void *unit_find(struct idr *p, int n);
295 static void ppp_setup(struct net_device *dev);
296
297 static const struct net_device_ops ppp_netdev_ops;
298
299 static struct class *ppp_class;
300
301 /* per net-namespace data */
ppp_pernet(struct net * net)302 static inline struct ppp_net *ppp_pernet(struct net *net)
303 {
304 return net_generic(net, ppp_net_id);
305 }
306
307 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
proto_to_npindex(int proto)308 static inline int proto_to_npindex(int proto)
309 {
310 switch (proto) {
311 case PPP_IP:
312 return NP_IP;
313 case PPP_IPV6:
314 return NP_IPV6;
315 case PPP_IPX:
316 return NP_IPX;
317 case PPP_AT:
318 return NP_AT;
319 case PPP_MPLS_UC:
320 return NP_MPLS_UC;
321 case PPP_MPLS_MC:
322 return NP_MPLS_MC;
323 }
324 return -EINVAL;
325 }
326
327 /* Translates an NP index into a PPP protocol number */
328 static const int npindex_to_proto[NUM_NP] = {
329 PPP_IP,
330 PPP_IPV6,
331 PPP_IPX,
332 PPP_AT,
333 PPP_MPLS_UC,
334 PPP_MPLS_MC,
335 };
336
337 /* Translates an ethertype into an NP index */
ethertype_to_npindex(int ethertype)338 static inline int ethertype_to_npindex(int ethertype)
339 {
340 switch (ethertype) {
341 case ETH_P_IP:
342 return NP_IP;
343 case ETH_P_IPV6:
344 return NP_IPV6;
345 case ETH_P_IPX:
346 return NP_IPX;
347 case ETH_P_PPPTALK:
348 case ETH_P_ATALK:
349 return NP_AT;
350 case ETH_P_MPLS_UC:
351 return NP_MPLS_UC;
352 case ETH_P_MPLS_MC:
353 return NP_MPLS_MC;
354 }
355 return -1;
356 }
357
358 /* Translates an NP index into an ethertype */
359 static const int npindex_to_ethertype[NUM_NP] = {
360 ETH_P_IP,
361 ETH_P_IPV6,
362 ETH_P_IPX,
363 ETH_P_PPPTALK,
364 ETH_P_MPLS_UC,
365 ETH_P_MPLS_MC,
366 };
367
368 /*
369 * Locking shorthand.
370 */
371 #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
372 #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
373 #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
374 #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
375 #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
376 ppp_recv_lock(ppp); } while (0)
377 #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
378 ppp_xmit_unlock(ppp); } while (0)
379
380 /*
381 * /dev/ppp device routines.
382 * The /dev/ppp device is used by pppd to control the ppp unit.
383 * It supports the read, write, ioctl and poll functions.
384 * Open instances of /dev/ppp can be in one of three states:
385 * unattached, attached to a ppp unit, or attached to a ppp channel.
386 */
ppp_open(struct inode * inode,struct file * file)387 static int ppp_open(struct inode *inode, struct file *file)
388 {
389 /*
390 * This could (should?) be enforced by the permissions on /dev/ppp.
391 */
392 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
393 return -EPERM;
394 return 0;
395 }
396
ppp_release(struct inode * unused,struct file * file)397 static int ppp_release(struct inode *unused, struct file *file)
398 {
399 struct ppp_file *pf = file->private_data;
400 struct ppp *ppp;
401
402 if (pf) {
403 file->private_data = NULL;
404 if (pf->kind == INTERFACE) {
405 ppp = PF_TO_PPP(pf);
406 rtnl_lock();
407 if (file == ppp->owner)
408 unregister_netdevice(ppp->dev);
409 rtnl_unlock();
410 }
411 if (refcount_dec_and_test(&pf->refcnt)) {
412 switch (pf->kind) {
413 case INTERFACE:
414 ppp_destroy_interface(PF_TO_PPP(pf));
415 break;
416 case CHANNEL:
417 ppp_destroy_channel(PF_TO_CHANNEL(pf));
418 break;
419 }
420 }
421 }
422 return 0;
423 }
424
ppp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)425 static ssize_t ppp_read(struct file *file, char __user *buf,
426 size_t count, loff_t *ppos)
427 {
428 struct ppp_file *pf = file->private_data;
429 DECLARE_WAITQUEUE(wait, current);
430 ssize_t ret;
431 struct sk_buff *skb = NULL;
432 struct iovec iov;
433 struct iov_iter to;
434
435 ret = count;
436
437 if (!pf)
438 return -ENXIO;
439 add_wait_queue(&pf->rwait, &wait);
440 for (;;) {
441 set_current_state(TASK_INTERRUPTIBLE);
442 skb = skb_dequeue(&pf->rq);
443 if (skb)
444 break;
445 ret = 0;
446 if (pf->dead)
447 break;
448 if (pf->kind == INTERFACE) {
449 /*
450 * Return 0 (EOF) on an interface that has no
451 * channels connected, unless it is looping
452 * network traffic (demand mode).
453 */
454 struct ppp *ppp = PF_TO_PPP(pf);
455
456 ppp_recv_lock(ppp);
457 if (ppp->n_channels == 0 &&
458 (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
459 ppp_recv_unlock(ppp);
460 break;
461 }
462 ppp_recv_unlock(ppp);
463 }
464 ret = -EAGAIN;
465 if (file->f_flags & O_NONBLOCK)
466 break;
467 ret = -ERESTARTSYS;
468 if (signal_pending(current))
469 break;
470 schedule();
471 }
472 set_current_state(TASK_RUNNING);
473 remove_wait_queue(&pf->rwait, &wait);
474
475 if (!skb)
476 goto out;
477
478 ret = -EOVERFLOW;
479 if (skb->len > count)
480 goto outf;
481 ret = -EFAULT;
482 iov.iov_base = buf;
483 iov.iov_len = count;
484 iov_iter_init(&to, ITER_DEST, &iov, 1, count);
485 if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
486 goto outf;
487 ret = skb->len;
488
489 outf:
490 kfree_skb(skb);
491 out:
492 return ret;
493 }
494
ppp_check_packet(struct sk_buff * skb,size_t count)495 static bool ppp_check_packet(struct sk_buff *skb, size_t count)
496 {
497 /* LCP packets must include LCP header which 4 bytes long:
498 * 1-byte code, 1-byte identifier, and 2-byte length.
499 */
500 return get_unaligned_be16(skb->data) != PPP_LCP ||
501 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
502 }
503
ppp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)504 static ssize_t ppp_write(struct file *file, const char __user *buf,
505 size_t count, loff_t *ppos)
506 {
507 struct ppp_file *pf = file->private_data;
508 struct sk_buff *skb;
509 ssize_t ret;
510
511 if (!pf)
512 return -ENXIO;
513 /* All PPP packets should start with the 2-byte protocol */
514 if (count < PPP_PROTO_LEN)
515 return -EINVAL;
516 ret = -ENOMEM;
517 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
518 if (!skb)
519 goto out;
520 skb_reserve(skb, pf->hdrlen);
521 ret = -EFAULT;
522 if (copy_from_user(skb_put(skb, count), buf, count)) {
523 kfree_skb(skb);
524 goto out;
525 }
526 ret = -EINVAL;
527 if (unlikely(!ppp_check_packet(skb, count))) {
528 kfree_skb(skb);
529 goto out;
530 }
531
532 switch (pf->kind) {
533 case INTERFACE:
534 ppp_xmit_process(PF_TO_PPP(pf), skb);
535 break;
536 case CHANNEL:
537 skb_queue_tail(&pf->xq, skb);
538 ppp_channel_push(PF_TO_CHANNEL(pf));
539 break;
540 }
541
542 ret = count;
543
544 out:
545 return ret;
546 }
547
548 /* No kernel lock - fine */
ppp_poll(struct file * file,poll_table * wait)549 static __poll_t ppp_poll(struct file *file, poll_table *wait)
550 {
551 struct ppp_file *pf = file->private_data;
552 __poll_t mask;
553
554 if (!pf)
555 return 0;
556 poll_wait(file, &pf->rwait, wait);
557 mask = EPOLLOUT | EPOLLWRNORM;
558 if (skb_peek(&pf->rq))
559 mask |= EPOLLIN | EPOLLRDNORM;
560 if (pf->dead)
561 mask |= EPOLLHUP;
562 else if (pf->kind == INTERFACE) {
563 /* see comment in ppp_read */
564 struct ppp *ppp = PF_TO_PPP(pf);
565
566 ppp_recv_lock(ppp);
567 if (ppp->n_channels == 0 &&
568 (ppp->flags & SC_LOOP_TRAFFIC) == 0)
569 mask |= EPOLLIN | EPOLLRDNORM;
570 ppp_recv_unlock(ppp);
571 }
572
573 return mask;
574 }
575
576 #ifdef CONFIG_PPP_FILTER
get_filter(struct sock_fprog * uprog)577 static struct bpf_prog *get_filter(struct sock_fprog *uprog)
578 {
579 struct sock_fprog_kern fprog;
580 struct bpf_prog *res = NULL;
581 int err;
582
583 if (!uprog->len)
584 return NULL;
585
586 /* uprog->len is unsigned short, so no overflow here */
587 fprog.len = uprog->len;
588 fprog.filter = memdup_user(uprog->filter,
589 uprog->len * sizeof(struct sock_filter));
590 if (IS_ERR(fprog.filter))
591 return ERR_CAST(fprog.filter);
592
593 err = bpf_prog_create(&res, &fprog);
594 kfree(fprog.filter);
595
596 return err ? ERR_PTR(err) : res;
597 }
598
ppp_get_filter(struct sock_fprog __user * p)599 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
600 {
601 struct sock_fprog uprog;
602
603 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
604 return ERR_PTR(-EFAULT);
605 return get_filter(&uprog);
606 }
607
608 #ifdef CONFIG_COMPAT
609 struct sock_fprog32 {
610 unsigned short len;
611 compat_caddr_t filter;
612 };
613
614 #define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32)
615 #define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32)
616
compat_ppp_get_filter(struct sock_fprog32 __user * p)617 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
618 {
619 struct sock_fprog32 uprog32;
620 struct sock_fprog uprog;
621
622 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
623 return ERR_PTR(-EFAULT);
624 uprog.len = uprog32.len;
625 uprog.filter = compat_ptr(uprog32.filter);
626 return get_filter(&uprog);
627 }
628 #endif
629 #endif
630
631 /* Bridge one PPP channel to another.
632 * When two channels are bridged, ppp_input on one channel is redirected to
633 * the other's ops->start_xmit handler.
634 * In order to safely bridge channels we must reject channels which are already
635 * part of a bridge instance, or which form part of an existing unit.
636 * Once successfully bridged, each channel holds a reference on the other
637 * to prevent it being freed while the bridge is extant.
638 */
ppp_bridge_channels(struct channel * pch,struct channel * pchb)639 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
640 {
641 write_lock_bh(&pch->upl);
642 if (pch->ppp ||
643 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
644 write_unlock_bh(&pch->upl);
645 return -EALREADY;
646 }
647 refcount_inc(&pchb->file.refcnt);
648 rcu_assign_pointer(pch->bridge, pchb);
649 write_unlock_bh(&pch->upl);
650
651 write_lock_bh(&pchb->upl);
652 if (pchb->ppp ||
653 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
654 write_unlock_bh(&pchb->upl);
655 goto err_unset;
656 }
657 refcount_inc(&pch->file.refcnt);
658 rcu_assign_pointer(pchb->bridge, pch);
659 write_unlock_bh(&pchb->upl);
660
661 return 0;
662
663 err_unset:
664 write_lock_bh(&pch->upl);
665 /* Re-read pch->bridge with upl held in case it was modified concurrently */
666 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
667 RCU_INIT_POINTER(pch->bridge, NULL);
668 write_unlock_bh(&pch->upl);
669 synchronize_rcu();
670
671 if (pchb)
672 if (refcount_dec_and_test(&pchb->file.refcnt))
673 ppp_destroy_channel(pchb);
674
675 return -EALREADY;
676 }
677
ppp_unbridge_channels(struct channel * pch)678 static int ppp_unbridge_channels(struct channel *pch)
679 {
680 struct channel *pchb, *pchbb;
681
682 write_lock_bh(&pch->upl);
683 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
684 if (!pchb) {
685 write_unlock_bh(&pch->upl);
686 return -EINVAL;
687 }
688 RCU_INIT_POINTER(pch->bridge, NULL);
689 write_unlock_bh(&pch->upl);
690
691 /* Only modify pchb if phcb->bridge points back to pch.
692 * If not, it implies that there has been a race unbridging (and possibly
693 * even rebridging) pchb. We should leave pchb alone to avoid either a
694 * refcount underflow, or breaking another established bridge instance.
695 */
696 write_lock_bh(&pchb->upl);
697 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
698 if (pchbb == pch)
699 RCU_INIT_POINTER(pchb->bridge, NULL);
700 write_unlock_bh(&pchb->upl);
701
702 synchronize_rcu();
703
704 if (pchbb == pch)
705 if (refcount_dec_and_test(&pch->file.refcnt))
706 ppp_destroy_channel(pch);
707
708 if (refcount_dec_and_test(&pchb->file.refcnt))
709 ppp_destroy_channel(pchb);
710
711 return 0;
712 }
713
ppp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)714 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
715 {
716 struct ppp_file *pf;
717 struct ppp *ppp;
718 int err = -EFAULT, val, val2, i;
719 struct ppp_idle32 idle32;
720 struct ppp_idle64 idle64;
721 struct npioctl npi;
722 int unit, cflags;
723 struct slcompress *vj;
724 void __user *argp = (void __user *)arg;
725 int __user *p = argp;
726
727 mutex_lock(&ppp_mutex);
728
729 pf = file->private_data;
730 if (!pf) {
731 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
732 pf, file, cmd, arg);
733 goto out;
734 }
735
736 if (cmd == PPPIOCDETACH) {
737 /*
738 * PPPIOCDETACH is no longer supported as it was heavily broken,
739 * and is only known to have been used by pppd older than
740 * ppp-2.4.2 (released November 2003).
741 */
742 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
743 current->comm, current->pid);
744 err = -EINVAL;
745 goto out;
746 }
747
748 if (pf->kind == CHANNEL) {
749 struct channel *pch, *pchb;
750 struct ppp_channel *chan;
751 struct ppp_net *pn;
752
753 pch = PF_TO_CHANNEL(pf);
754
755 switch (cmd) {
756 case PPPIOCCONNECT:
757 if (get_user(unit, p))
758 break;
759 err = ppp_connect_channel(pch, unit);
760 break;
761
762 case PPPIOCDISCONN:
763 err = ppp_disconnect_channel(pch);
764 break;
765
766 case PPPIOCBRIDGECHAN:
767 if (get_user(unit, p))
768 break;
769 err = -ENXIO;
770 pn = ppp_pernet(current->nsproxy->net_ns);
771 spin_lock_bh(&pn->all_channels_lock);
772 pchb = ppp_find_channel(pn, unit);
773 /* Hold a reference to prevent pchb being freed while
774 * we establish the bridge.
775 */
776 if (pchb)
777 refcount_inc(&pchb->file.refcnt);
778 spin_unlock_bh(&pn->all_channels_lock);
779 if (!pchb)
780 break;
781 err = ppp_bridge_channels(pch, pchb);
782 /* Drop earlier refcount now bridge establishment is complete */
783 if (refcount_dec_and_test(&pchb->file.refcnt))
784 ppp_destroy_channel(pchb);
785 break;
786
787 case PPPIOCUNBRIDGECHAN:
788 err = ppp_unbridge_channels(pch);
789 break;
790
791 default:
792 down_read(&pch->chan_sem);
793 chan = pch->chan;
794 err = -ENOTTY;
795 if (chan && chan->ops->ioctl)
796 err = chan->ops->ioctl(chan, cmd, arg);
797 up_read(&pch->chan_sem);
798 }
799 goto out;
800 }
801
802 if (pf->kind != INTERFACE) {
803 /* can't happen */
804 pr_err("PPP: not interface or channel??\n");
805 err = -EINVAL;
806 goto out;
807 }
808
809 ppp = PF_TO_PPP(pf);
810 switch (cmd) {
811 case PPPIOCSMRU:
812 if (get_user(val, p))
813 break;
814 ppp->mru = val;
815 err = 0;
816 break;
817
818 case PPPIOCSFLAGS:
819 if (get_user(val, p))
820 break;
821 ppp_lock(ppp);
822 cflags = ppp->flags & ~val;
823 #ifdef CONFIG_PPP_MULTILINK
824 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
825 ppp->nextseq = 0;
826 #endif
827 ppp->flags = val & SC_FLAG_BITS;
828 ppp_unlock(ppp);
829 if (cflags & SC_CCP_OPEN)
830 ppp_ccp_closed(ppp);
831 err = 0;
832 break;
833
834 case PPPIOCGFLAGS:
835 val = ppp->flags | ppp->xstate | ppp->rstate;
836 if (put_user(val, p))
837 break;
838 err = 0;
839 break;
840
841 case PPPIOCSCOMPRESS:
842 {
843 struct ppp_option_data data;
844 if (copy_from_user(&data, argp, sizeof(data)))
845 err = -EFAULT;
846 else
847 err = ppp_set_compress(ppp, &data);
848 break;
849 }
850 case PPPIOCGUNIT:
851 if (put_user(ppp->file.index, p))
852 break;
853 err = 0;
854 break;
855
856 case PPPIOCSDEBUG:
857 if (get_user(val, p))
858 break;
859 ppp->debug = val;
860 err = 0;
861 break;
862
863 case PPPIOCGDEBUG:
864 if (put_user(ppp->debug, p))
865 break;
866 err = 0;
867 break;
868
869 case PPPIOCGIDLE32:
870 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
871 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
872 if (copy_to_user(argp, &idle32, sizeof(idle32)))
873 break;
874 err = 0;
875 break;
876
877 case PPPIOCGIDLE64:
878 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
879 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
880 if (copy_to_user(argp, &idle64, sizeof(idle64)))
881 break;
882 err = 0;
883 break;
884
885 case PPPIOCSMAXCID:
886 if (get_user(val, p))
887 break;
888 val2 = 15;
889 if ((val >> 16) != 0) {
890 val2 = val >> 16;
891 val &= 0xffff;
892 }
893 vj = slhc_init(val2+1, val+1);
894 if (IS_ERR(vj)) {
895 err = PTR_ERR(vj);
896 break;
897 }
898 ppp_lock(ppp);
899 if (ppp->vj)
900 slhc_free(ppp->vj);
901 ppp->vj = vj;
902 ppp_unlock(ppp);
903 err = 0;
904 break;
905
906 case PPPIOCGNPMODE:
907 case PPPIOCSNPMODE:
908 if (copy_from_user(&npi, argp, sizeof(npi)))
909 break;
910 err = proto_to_npindex(npi.protocol);
911 if (err < 0)
912 break;
913 i = err;
914 if (cmd == PPPIOCGNPMODE) {
915 err = -EFAULT;
916 npi.mode = ppp->npmode[i];
917 if (copy_to_user(argp, &npi, sizeof(npi)))
918 break;
919 } else {
920 ppp->npmode[i] = npi.mode;
921 /* we may be able to transmit more packets now (??) */
922 netif_wake_queue(ppp->dev);
923 }
924 err = 0;
925 break;
926
927 #ifdef CONFIG_PPP_FILTER
928 case PPPIOCSPASS:
929 case PPPIOCSACTIVE:
930 {
931 struct bpf_prog *filter = ppp_get_filter(argp);
932 struct bpf_prog **which;
933
934 if (IS_ERR(filter)) {
935 err = PTR_ERR(filter);
936 break;
937 }
938 if (cmd == PPPIOCSPASS)
939 which = &ppp->pass_filter;
940 else
941 which = &ppp->active_filter;
942 ppp_lock(ppp);
943 if (*which)
944 bpf_prog_destroy(*which);
945 *which = filter;
946 ppp_unlock(ppp);
947 err = 0;
948 break;
949 }
950 #endif /* CONFIG_PPP_FILTER */
951
952 #ifdef CONFIG_PPP_MULTILINK
953 case PPPIOCSMRRU:
954 if (get_user(val, p))
955 break;
956 ppp_recv_lock(ppp);
957 ppp->mrru = val;
958 ppp_recv_unlock(ppp);
959 err = 0;
960 break;
961 #endif /* CONFIG_PPP_MULTILINK */
962
963 default:
964 err = -ENOTTY;
965 }
966
967 out:
968 mutex_unlock(&ppp_mutex);
969
970 return err;
971 }
972
973 #ifdef CONFIG_COMPAT
974 struct ppp_option_data32 {
975 compat_uptr_t ptr;
976 u32 length;
977 compat_int_t transmit;
978 };
979 #define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)
980
ppp_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)981 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
982 {
983 struct ppp_file *pf;
984 int err = -ENOIOCTLCMD;
985 void __user *argp = (void __user *)arg;
986
987 mutex_lock(&ppp_mutex);
988
989 pf = file->private_data;
990 if (pf && pf->kind == INTERFACE) {
991 struct ppp *ppp = PF_TO_PPP(pf);
992 switch (cmd) {
993 #ifdef CONFIG_PPP_FILTER
994 case PPPIOCSPASS32:
995 case PPPIOCSACTIVE32:
996 {
997 struct bpf_prog *filter = compat_ppp_get_filter(argp);
998 struct bpf_prog **which;
999
1000 if (IS_ERR(filter)) {
1001 err = PTR_ERR(filter);
1002 break;
1003 }
1004 if (cmd == PPPIOCSPASS32)
1005 which = &ppp->pass_filter;
1006 else
1007 which = &ppp->active_filter;
1008 ppp_lock(ppp);
1009 if (*which)
1010 bpf_prog_destroy(*which);
1011 *which = filter;
1012 ppp_unlock(ppp);
1013 err = 0;
1014 break;
1015 }
1016 #endif /* CONFIG_PPP_FILTER */
1017 case PPPIOCSCOMPRESS32:
1018 {
1019 struct ppp_option_data32 data32;
1020 if (copy_from_user(&data32, argp, sizeof(data32))) {
1021 err = -EFAULT;
1022 } else {
1023 struct ppp_option_data data = {
1024 .ptr = compat_ptr(data32.ptr),
1025 .length = data32.length,
1026 .transmit = data32.transmit
1027 };
1028 err = ppp_set_compress(ppp, &data);
1029 }
1030 break;
1031 }
1032 }
1033 }
1034 mutex_unlock(&ppp_mutex);
1035
1036 /* all other commands have compatible arguments */
1037 if (err == -ENOIOCTLCMD)
1038 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1039
1040 return err;
1041 }
1042 #endif
1043
ppp_unattached_ioctl(struct net * net,struct ppp_file * pf,struct file * file,unsigned int cmd,unsigned long arg)1044 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1045 struct file *file, unsigned int cmd, unsigned long arg)
1046 {
1047 int unit, err = -EFAULT;
1048 struct ppp *ppp;
1049 struct channel *chan;
1050 struct ppp_net *pn;
1051 int __user *p = (int __user *)arg;
1052
1053 switch (cmd) {
1054 case PPPIOCNEWUNIT:
1055 /* Create a new ppp unit */
1056 if (get_user(unit, p))
1057 break;
1058 err = ppp_create_interface(net, file, &unit);
1059 if (err < 0)
1060 break;
1061
1062 err = -EFAULT;
1063 if (put_user(unit, p))
1064 break;
1065 err = 0;
1066 break;
1067
1068 case PPPIOCATTACH:
1069 /* Attach to an existing ppp unit */
1070 if (get_user(unit, p))
1071 break;
1072 err = -ENXIO;
1073 pn = ppp_pernet(net);
1074 mutex_lock(&pn->all_ppp_mutex);
1075 ppp = ppp_find_unit(pn, unit);
1076 if (ppp) {
1077 refcount_inc(&ppp->file.refcnt);
1078 file->private_data = &ppp->file;
1079 err = 0;
1080 }
1081 mutex_unlock(&pn->all_ppp_mutex);
1082 break;
1083
1084 case PPPIOCATTCHAN:
1085 if (get_user(unit, p))
1086 break;
1087 err = -ENXIO;
1088 pn = ppp_pernet(net);
1089 spin_lock_bh(&pn->all_channels_lock);
1090 chan = ppp_find_channel(pn, unit);
1091 if (chan) {
1092 refcount_inc(&chan->file.refcnt);
1093 file->private_data = &chan->file;
1094 err = 0;
1095 }
1096 spin_unlock_bh(&pn->all_channels_lock);
1097 break;
1098
1099 default:
1100 err = -ENOTTY;
1101 }
1102
1103 return err;
1104 }
1105
1106 static const struct file_operations ppp_device_fops = {
1107 .owner = THIS_MODULE,
1108 .read = ppp_read,
1109 .write = ppp_write,
1110 .poll = ppp_poll,
1111 .unlocked_ioctl = ppp_ioctl,
1112 #ifdef CONFIG_COMPAT
1113 .compat_ioctl = ppp_compat_ioctl,
1114 #endif
1115 .open = ppp_open,
1116 .release = ppp_release,
1117 .llseek = noop_llseek,
1118 };
1119
ppp_init_net(struct net * net)1120 static __net_init int ppp_init_net(struct net *net)
1121 {
1122 struct ppp_net *pn = net_generic(net, ppp_net_id);
1123
1124 idr_init(&pn->units_idr);
1125 mutex_init(&pn->all_ppp_mutex);
1126
1127 INIT_LIST_HEAD(&pn->all_channels);
1128 INIT_LIST_HEAD(&pn->new_channels);
1129
1130 spin_lock_init(&pn->all_channels_lock);
1131
1132 return 0;
1133 }
1134
ppp_exit_net(struct net * net)1135 static __net_exit void ppp_exit_net(struct net *net)
1136 {
1137 struct ppp_net *pn = net_generic(net, ppp_net_id);
1138 struct net_device *dev;
1139 struct net_device *aux;
1140 struct ppp *ppp;
1141 LIST_HEAD(list);
1142 int id;
1143
1144 rtnl_lock();
1145 for_each_netdev_safe(net, dev, aux) {
1146 if (dev->netdev_ops == &ppp_netdev_ops)
1147 unregister_netdevice_queue(dev, &list);
1148 }
1149
1150 idr_for_each_entry(&pn->units_idr, ppp, id)
1151 /* Skip devices already unregistered by previous loop */
1152 if (!net_eq(dev_net(ppp->dev), net))
1153 unregister_netdevice_queue(ppp->dev, &list);
1154
1155 unregister_netdevice_many(&list);
1156 rtnl_unlock();
1157
1158 mutex_destroy(&pn->all_ppp_mutex);
1159 idr_destroy(&pn->units_idr);
1160 WARN_ON_ONCE(!list_empty(&pn->all_channels));
1161 WARN_ON_ONCE(!list_empty(&pn->new_channels));
1162 }
1163
1164 static struct pernet_operations ppp_net_ops = {
1165 .init = ppp_init_net,
1166 .exit = ppp_exit_net,
1167 .id = &ppp_net_id,
1168 .size = sizeof(struct ppp_net),
1169 };
1170
ppp_unit_register(struct ppp * ppp,int unit,bool ifname_is_set)1171 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1172 {
1173 struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1174 int ret;
1175
1176 mutex_lock(&pn->all_ppp_mutex);
1177
1178 if (unit < 0) {
1179 ret = unit_get(&pn->units_idr, ppp, 0);
1180 if (ret < 0)
1181 goto err;
1182 if (!ifname_is_set) {
1183 while (1) {
1184 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
1185 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
1186 break;
1187 unit_put(&pn->units_idr, ret);
1188 ret = unit_get(&pn->units_idr, ppp, ret + 1);
1189 if (ret < 0)
1190 goto err;
1191 }
1192 }
1193 } else {
1194 /* Caller asked for a specific unit number. Fail with -EEXIST
1195 * if unavailable. For backward compatibility, return -EEXIST
1196 * too if idr allocation fails; this makes pppd retry without
1197 * requesting a specific unit number.
1198 */
1199 if (unit_find(&pn->units_idr, unit)) {
1200 ret = -EEXIST;
1201 goto err;
1202 }
1203 ret = unit_set(&pn->units_idr, ppp, unit);
1204 if (ret < 0) {
1205 /* Rewrite error for backward compatibility */
1206 ret = -EEXIST;
1207 goto err;
1208 }
1209 }
1210 ppp->file.index = ret;
1211
1212 if (!ifname_is_set)
1213 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1214
1215 mutex_unlock(&pn->all_ppp_mutex);
1216
1217 ret = register_netdevice(ppp->dev);
1218 if (ret < 0)
1219 goto err_unit;
1220
1221 atomic_inc(&ppp_unit_count);
1222
1223 return 0;
1224
1225 err_unit:
1226 mutex_lock(&pn->all_ppp_mutex);
1227 unit_put(&pn->units_idr, ppp->file.index);
1228 err:
1229 mutex_unlock(&pn->all_ppp_mutex);
1230
1231 return ret;
1232 }
1233
ppp_dev_configure(struct net * src_net,struct net_device * dev,const struct ppp_config * conf)1234 static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1235 const struct ppp_config *conf)
1236 {
1237 struct ppp *ppp = netdev_priv(dev);
1238 int indx;
1239 int err;
1240 int cpu;
1241
1242 ppp->dev = dev;
1243 ppp->ppp_net = src_net;
1244 ppp->mru = PPP_MRU;
1245 ppp->owner = conf->file;
1246
1247 init_ppp_file(&ppp->file, INTERFACE);
1248 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1249
1250 for (indx = 0; indx < NUM_NP; ++indx)
1251 ppp->npmode[indx] = NPMODE_PASS;
1252 INIT_LIST_HEAD(&ppp->channels);
1253 spin_lock_init(&ppp->rlock);
1254 spin_lock_init(&ppp->wlock);
1255
1256 ppp->xmit_recursion = alloc_percpu(int);
1257 if (!ppp->xmit_recursion) {
1258 err = -ENOMEM;
1259 goto err1;
1260 }
1261 for_each_possible_cpu(cpu)
1262 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1263
1264 #ifdef CONFIG_PPP_MULTILINK
1265 ppp->minseq = -1;
1266 skb_queue_head_init(&ppp->mrq);
1267 #endif /* CONFIG_PPP_MULTILINK */
1268 #ifdef CONFIG_PPP_FILTER
1269 ppp->pass_filter = NULL;
1270 ppp->active_filter = NULL;
1271 #endif /* CONFIG_PPP_FILTER */
1272
1273 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1274 if (err < 0)
1275 goto err2;
1276
1277 conf->file->private_data = &ppp->file;
1278
1279 return 0;
1280 err2:
1281 free_percpu(ppp->xmit_recursion);
1282 err1:
1283 return err;
1284 }
1285
1286 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1287 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
1288 };
1289
ppp_nl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1290 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1291 struct netlink_ext_ack *extack)
1292 {
1293 if (!data)
1294 return -EINVAL;
1295
1296 if (!data[IFLA_PPP_DEV_FD])
1297 return -EINVAL;
1298 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1299 return -EBADF;
1300
1301 return 0;
1302 }
1303
ppp_nl_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1304 static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1305 struct nlattr *tb[], struct nlattr *data[],
1306 struct netlink_ext_ack *extack)
1307 {
1308 struct ppp_config conf = {
1309 .unit = -1,
1310 .ifname_is_set = true,
1311 };
1312 struct file *file;
1313 int err;
1314
1315 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1316 if (!file)
1317 return -EBADF;
1318
1319 /* rtnl_lock is already held here, but ppp_create_interface() locks
1320 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1321 * possible deadlock due to lock order inversion, at the cost of
1322 * pushing the problem back to userspace.
1323 */
1324 if (!mutex_trylock(&ppp_mutex)) {
1325 err = -EBUSY;
1326 goto out;
1327 }
1328
1329 if (file->f_op != &ppp_device_fops || file->private_data) {
1330 err = -EBADF;
1331 goto out_unlock;
1332 }
1333
1334 conf.file = file;
1335
1336 /* Don't use device name generated by the rtnetlink layer when ifname
1337 * isn't specified. Let ppp_dev_configure() set the device name using
1338 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1339 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1340 */
1341 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1342 conf.ifname_is_set = false;
1343
1344 err = ppp_dev_configure(src_net, dev, &conf);
1345
1346 out_unlock:
1347 mutex_unlock(&ppp_mutex);
1348 out:
1349 fput(file);
1350
1351 return err;
1352 }
1353
ppp_nl_dellink(struct net_device * dev,struct list_head * head)1354 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1355 {
1356 unregister_netdevice_queue(dev, head);
1357 }
1358
ppp_nl_get_size(const struct net_device * dev)1359 static size_t ppp_nl_get_size(const struct net_device *dev)
1360 {
1361 return 0;
1362 }
1363
ppp_nl_fill_info(struct sk_buff * skb,const struct net_device * dev)1364 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1365 {
1366 return 0;
1367 }
1368
ppp_nl_get_link_net(const struct net_device * dev)1369 static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1370 {
1371 struct ppp *ppp = netdev_priv(dev);
1372
1373 return ppp->ppp_net;
1374 }
1375
1376 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1377 .kind = "ppp",
1378 .maxtype = IFLA_PPP_MAX,
1379 .policy = ppp_nl_policy,
1380 .priv_size = sizeof(struct ppp),
1381 .setup = ppp_setup,
1382 .validate = ppp_nl_validate,
1383 .newlink = ppp_nl_newlink,
1384 .dellink = ppp_nl_dellink,
1385 .get_size = ppp_nl_get_size,
1386 .fill_info = ppp_nl_fill_info,
1387 .get_link_net = ppp_nl_get_link_net,
1388 };
1389
1390 #define PPP_MAJOR 108
1391
1392 /* Called at boot time if ppp is compiled into the kernel,
1393 or at module load time (from init_module) if compiled as a module. */
ppp_init(void)1394 static int __init ppp_init(void)
1395 {
1396 int err;
1397
1398 pr_info("PPP generic driver version " PPP_VERSION "\n");
1399
1400 err = register_pernet_device(&ppp_net_ops);
1401 if (err) {
1402 pr_err("failed to register PPP pernet device (%d)\n", err);
1403 goto out;
1404 }
1405
1406 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1407 if (err) {
1408 pr_err("failed to register PPP device (%d)\n", err);
1409 goto out_net;
1410 }
1411
1412 ppp_class = class_create("ppp");
1413 if (IS_ERR(ppp_class)) {
1414 err = PTR_ERR(ppp_class);
1415 goto out_chrdev;
1416 }
1417
1418 err = rtnl_link_register(&ppp_link_ops);
1419 if (err) {
1420 pr_err("failed to register rtnetlink PPP handler\n");
1421 goto out_class;
1422 }
1423
1424 /* not a big deal if we fail here :-) */
1425 device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1426
1427 return 0;
1428
1429 out_class:
1430 class_destroy(ppp_class);
1431 out_chrdev:
1432 unregister_chrdev(PPP_MAJOR, "ppp");
1433 out_net:
1434 unregister_pernet_device(&ppp_net_ops);
1435 out:
1436 return err;
1437 }
1438
1439 /*
1440 * Network interface unit routines.
1441 */
1442 static netdev_tx_t
ppp_start_xmit(struct sk_buff * skb,struct net_device * dev)1443 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1444 {
1445 struct ppp *ppp = netdev_priv(dev);
1446 int npi, proto;
1447 unsigned char *pp;
1448
1449 npi = ethertype_to_npindex(ntohs(skb->protocol));
1450 if (npi < 0)
1451 goto outf;
1452
1453 /* Drop, accept or reject the packet */
1454 switch (ppp->npmode[npi]) {
1455 case NPMODE_PASS:
1456 break;
1457 case NPMODE_QUEUE:
1458 /* it would be nice to have a way to tell the network
1459 system to queue this one up for later. */
1460 goto outf;
1461 case NPMODE_DROP:
1462 case NPMODE_ERROR:
1463 goto outf;
1464 }
1465
1466 /* Put the 2-byte PPP protocol number on the front,
1467 making sure there is room for the address and control fields. */
1468 if (skb_cow_head(skb, PPP_HDRLEN))
1469 goto outf;
1470
1471 pp = skb_push(skb, 2);
1472 proto = npindex_to_proto[npi];
1473 put_unaligned_be16(proto, pp);
1474
1475 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1476 ppp_xmit_process(ppp, skb);
1477
1478 return NETDEV_TX_OK;
1479
1480 outf:
1481 kfree_skb(skb);
1482 ++dev->stats.tx_dropped;
1483 return NETDEV_TX_OK;
1484 }
1485
1486 static int
ppp_net_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * addr,int cmd)1487 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1488 void __user *addr, int cmd)
1489 {
1490 struct ppp *ppp = netdev_priv(dev);
1491 int err = -EFAULT;
1492 struct ppp_stats stats;
1493 struct ppp_comp_stats cstats;
1494 char *vers;
1495
1496 switch (cmd) {
1497 case SIOCGPPPSTATS:
1498 ppp_get_stats(ppp, &stats);
1499 if (copy_to_user(addr, &stats, sizeof(stats)))
1500 break;
1501 err = 0;
1502 break;
1503
1504 case SIOCGPPPCSTATS:
1505 memset(&cstats, 0, sizeof(cstats));
1506 if (ppp->xc_state)
1507 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1508 if (ppp->rc_state)
1509 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1510 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1511 break;
1512 err = 0;
1513 break;
1514
1515 case SIOCGPPPVER:
1516 vers = PPP_VERSION;
1517 if (copy_to_user(addr, vers, strlen(vers) + 1))
1518 break;
1519 err = 0;
1520 break;
1521
1522 default:
1523 err = -EINVAL;
1524 }
1525
1526 return err;
1527 }
1528
1529 static void
ppp_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats64)1530 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1531 {
1532 struct ppp *ppp = netdev_priv(dev);
1533
1534 ppp_recv_lock(ppp);
1535 stats64->rx_packets = ppp->stats64.rx_packets;
1536 stats64->rx_bytes = ppp->stats64.rx_bytes;
1537 ppp_recv_unlock(ppp);
1538
1539 ppp_xmit_lock(ppp);
1540 stats64->tx_packets = ppp->stats64.tx_packets;
1541 stats64->tx_bytes = ppp->stats64.tx_bytes;
1542 ppp_xmit_unlock(ppp);
1543
1544 stats64->rx_errors = dev->stats.rx_errors;
1545 stats64->tx_errors = dev->stats.tx_errors;
1546 stats64->rx_dropped = dev->stats.rx_dropped;
1547 stats64->tx_dropped = dev->stats.tx_dropped;
1548 stats64->rx_length_errors = dev->stats.rx_length_errors;
1549 }
1550
ppp_dev_init(struct net_device * dev)1551 static int ppp_dev_init(struct net_device *dev)
1552 {
1553 struct ppp *ppp;
1554
1555 netdev_lockdep_set_classes(dev);
1556
1557 ppp = netdev_priv(dev);
1558 /* Let the netdevice take a reference on the ppp file. This ensures
1559 * that ppp_destroy_interface() won't run before the device gets
1560 * unregistered.
1561 */
1562 refcount_inc(&ppp->file.refcnt);
1563
1564 return 0;
1565 }
1566
ppp_dev_uninit(struct net_device * dev)1567 static void ppp_dev_uninit(struct net_device *dev)
1568 {
1569 struct ppp *ppp = netdev_priv(dev);
1570 struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1571
1572 ppp_lock(ppp);
1573 ppp->closing = 1;
1574 ppp_unlock(ppp);
1575
1576 mutex_lock(&pn->all_ppp_mutex);
1577 unit_put(&pn->units_idr, ppp->file.index);
1578 mutex_unlock(&pn->all_ppp_mutex);
1579
1580 ppp->owner = NULL;
1581
1582 ppp->file.dead = 1;
1583 wake_up_interruptible(&ppp->file.rwait);
1584 }
1585
ppp_dev_priv_destructor(struct net_device * dev)1586 static void ppp_dev_priv_destructor(struct net_device *dev)
1587 {
1588 struct ppp *ppp;
1589
1590 ppp = netdev_priv(dev);
1591 if (refcount_dec_and_test(&ppp->file.refcnt))
1592 ppp_destroy_interface(ppp);
1593 }
1594
ppp_fill_forward_path(struct net_device_path_ctx * ctx,struct net_device_path * path)1595 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1596 struct net_device_path *path)
1597 {
1598 struct ppp *ppp = netdev_priv(ctx->dev);
1599 struct ppp_channel *chan;
1600 struct channel *pch;
1601
1602 if (ppp->flags & SC_MULTILINK)
1603 return -EOPNOTSUPP;
1604
1605 if (list_empty(&ppp->channels))
1606 return -ENODEV;
1607
1608 pch = list_first_entry(&ppp->channels, struct channel, clist);
1609 chan = pch->chan;
1610 if (!chan->ops->fill_forward_path)
1611 return -EOPNOTSUPP;
1612
1613 return chan->ops->fill_forward_path(ctx, path, chan);
1614 }
1615
1616 static const struct net_device_ops ppp_netdev_ops = {
1617 .ndo_init = ppp_dev_init,
1618 .ndo_uninit = ppp_dev_uninit,
1619 .ndo_start_xmit = ppp_start_xmit,
1620 .ndo_siocdevprivate = ppp_net_siocdevprivate,
1621 .ndo_get_stats64 = ppp_get_stats64,
1622 .ndo_fill_forward_path = ppp_fill_forward_path,
1623 };
1624
1625 static struct device_type ppp_type = {
1626 .name = "ppp",
1627 };
1628
ppp_setup(struct net_device * dev)1629 static void ppp_setup(struct net_device *dev)
1630 {
1631 dev->netdev_ops = &ppp_netdev_ops;
1632 SET_NETDEV_DEVTYPE(dev, &ppp_type);
1633
1634 dev->features |= NETIF_F_LLTX;
1635
1636 dev->hard_header_len = PPP_HDRLEN;
1637 dev->mtu = PPP_MRU;
1638 dev->addr_len = 0;
1639 dev->tx_queue_len = 3;
1640 dev->type = ARPHRD_PPP;
1641 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1642 dev->priv_destructor = ppp_dev_priv_destructor;
1643 netif_keep_dst(dev);
1644 }
1645
1646 /*
1647 * Transmit-side routines.
1648 */
1649
1650 /* Called to do any work queued up on the transmit side that can now be done */
__ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1651 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1652 {
1653 ppp_xmit_lock(ppp);
1654 if (!ppp->closing) {
1655 ppp_push(ppp);
1656
1657 if (skb)
1658 skb_queue_tail(&ppp->file.xq, skb);
1659 while (!ppp->xmit_pending &&
1660 (skb = skb_dequeue(&ppp->file.xq)))
1661 ppp_send_frame(ppp, skb);
1662 /* If there's no work left to do, tell the core net
1663 code that we can accept some more. */
1664 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1665 netif_wake_queue(ppp->dev);
1666 else
1667 netif_stop_queue(ppp->dev);
1668 } else {
1669 kfree_skb(skb);
1670 }
1671 ppp_xmit_unlock(ppp);
1672 }
1673
ppp_xmit_process(struct ppp * ppp,struct sk_buff * skb)1674 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1675 {
1676 local_bh_disable();
1677
1678 if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1679 goto err;
1680
1681 (*this_cpu_ptr(ppp->xmit_recursion))++;
1682 __ppp_xmit_process(ppp, skb);
1683 (*this_cpu_ptr(ppp->xmit_recursion))--;
1684
1685 local_bh_enable();
1686
1687 return;
1688
1689 err:
1690 local_bh_enable();
1691
1692 kfree_skb(skb);
1693
1694 if (net_ratelimit())
1695 netdev_err(ppp->dev, "recursion detected\n");
1696 }
1697
1698 static inline struct sk_buff *
pad_compress_skb(struct ppp * ppp,struct sk_buff * skb)1699 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1700 {
1701 struct sk_buff *new_skb;
1702 int len;
1703 int new_skb_size = ppp->dev->mtu +
1704 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1705 int compressor_skb_size = ppp->dev->mtu +
1706 ppp->xcomp->comp_extra + PPP_HDRLEN;
1707 new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1708 if (!new_skb) {
1709 if (net_ratelimit())
1710 netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n");
1711 return NULL;
1712 }
1713 if (ppp->dev->hard_header_len > PPP_HDRLEN)
1714 skb_reserve(new_skb,
1715 ppp->dev->hard_header_len - PPP_HDRLEN);
1716
1717 /* compressor still expects A/C bytes in hdr */
1718 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1719 new_skb->data, skb->len + 2,
1720 compressor_skb_size);
1721 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1722 consume_skb(skb);
1723 skb = new_skb;
1724 skb_put(skb, len);
1725 skb_pull(skb, 2); /* pull off A/C bytes */
1726 } else if (len == 0) {
1727 /* didn't compress, or CCP not up yet */
1728 consume_skb(new_skb);
1729 new_skb = skb;
1730 } else {
1731 /*
1732 * (len < 0)
1733 * MPPE requires that we do not send unencrypted
1734 * frames. The compressor will return -1 if we
1735 * should drop the frame. We cannot simply test
1736 * the compress_proto because MPPE and MPPC share
1737 * the same number.
1738 */
1739 if (net_ratelimit())
1740 netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
1741 kfree_skb(skb);
1742 consume_skb(new_skb);
1743 new_skb = NULL;
1744 }
1745 return new_skb;
1746 }
1747
1748 /*
1749 * Compress and send a frame.
1750 * The caller should have locked the xmit path,
1751 * and xmit_pending should be 0.
1752 */
1753 static void
ppp_send_frame(struct ppp * ppp,struct sk_buff * skb)1754 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1755 {
1756 int proto = PPP_PROTO(skb);
1757 struct sk_buff *new_skb;
1758 int len;
1759 unsigned char *cp;
1760
1761 skb->dev = ppp->dev;
1762
1763 if (proto < 0x8000) {
1764 #ifdef CONFIG_PPP_FILTER
1765 /* check if we should pass this packet */
1766 /* the filter instructions are constructed assuming
1767 a four-byte PPP header on each packet */
1768 *(u8 *)skb_push(skb, 2) = 1;
1769 if (ppp->pass_filter &&
1770 bpf_prog_run(ppp->pass_filter, skb) == 0) {
1771 if (ppp->debug & 1)
1772 netdev_printk(KERN_DEBUG, ppp->dev,
1773 "PPP: outbound frame "
1774 "not passed\n");
1775 kfree_skb(skb);
1776 return;
1777 }
1778 /* if this packet passes the active filter, record the time */
1779 if (!(ppp->active_filter &&
1780 bpf_prog_run(ppp->active_filter, skb) == 0))
1781 ppp->last_xmit = jiffies;
1782 skb_pull(skb, 2);
1783 #else
1784 /* for data packets, record the time */
1785 ppp->last_xmit = jiffies;
1786 #endif /* CONFIG_PPP_FILTER */
1787 }
1788
1789 ++ppp->stats64.tx_packets;
1790 ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1791
1792 switch (proto) {
1793 case PPP_IP:
1794 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1795 break;
1796 /* try to do VJ TCP header compression */
1797 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1798 GFP_ATOMIC);
1799 if (!new_skb) {
1800 netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n");
1801 goto drop;
1802 }
1803 skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1804 cp = skb->data + 2;
1805 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1806 new_skb->data + 2, &cp,
1807 !(ppp->flags & SC_NO_TCP_CCID));
1808 if (cp == skb->data + 2) {
1809 /* didn't compress */
1810 consume_skb(new_skb);
1811 } else {
1812 if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1813 proto = PPP_VJC_COMP;
1814 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1815 } else {
1816 proto = PPP_VJC_UNCOMP;
1817 cp[0] = skb->data[2];
1818 }
1819 consume_skb(skb);
1820 skb = new_skb;
1821 cp = skb_put(skb, len + 2);
1822 cp[0] = 0;
1823 cp[1] = proto;
1824 }
1825 break;
1826
1827 case PPP_CCP:
1828 /* peek at outbound CCP frames */
1829 ppp_ccp_peek(ppp, skb, 0);
1830 break;
1831 }
1832
1833 /* try to do packet compression */
1834 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1835 proto != PPP_LCP && proto != PPP_CCP) {
1836 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1837 if (net_ratelimit())
1838 netdev_err(ppp->dev,
1839 "ppp: compression required but "
1840 "down - pkt dropped.\n");
1841 goto drop;
1842 }
1843 skb = pad_compress_skb(ppp, skb);
1844 if (!skb)
1845 goto drop;
1846 }
1847
1848 /*
1849 * If we are waiting for traffic (demand dialling),
1850 * queue it up for pppd to receive.
1851 */
1852 if (ppp->flags & SC_LOOP_TRAFFIC) {
1853 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1854 goto drop;
1855 skb_queue_tail(&ppp->file.rq, skb);
1856 wake_up_interruptible(&ppp->file.rwait);
1857 return;
1858 }
1859
1860 ppp->xmit_pending = skb;
1861 ppp_push(ppp);
1862 return;
1863
1864 drop:
1865 kfree_skb(skb);
1866 ++ppp->dev->stats.tx_errors;
1867 }
1868
1869 /*
1870 * Try to send the frame in xmit_pending.
1871 * The caller should have the xmit path locked.
1872 */
1873 static void
ppp_push(struct ppp * ppp)1874 ppp_push(struct ppp *ppp)
1875 {
1876 struct list_head *list;
1877 struct channel *pch;
1878 struct sk_buff *skb = ppp->xmit_pending;
1879
1880 if (!skb)
1881 return;
1882
1883 list = &ppp->channels;
1884 if (list_empty(list)) {
1885 /* nowhere to send the packet, just drop it */
1886 ppp->xmit_pending = NULL;
1887 kfree_skb(skb);
1888 return;
1889 }
1890
1891 if ((ppp->flags & SC_MULTILINK) == 0) {
1892 /* not doing multilink: send it down the first channel */
1893 list = list->next;
1894 pch = list_entry(list, struct channel, clist);
1895
1896 spin_lock(&pch->downl);
1897 if (pch->chan) {
1898 if (pch->chan->ops->start_xmit(pch->chan, skb))
1899 ppp->xmit_pending = NULL;
1900 } else {
1901 /* channel got unregistered */
1902 kfree_skb(skb);
1903 ppp->xmit_pending = NULL;
1904 }
1905 spin_unlock(&pch->downl);
1906 return;
1907 }
1908
1909 #ifdef CONFIG_PPP_MULTILINK
1910 /* Multilink: fragment the packet over as many links
1911 as can take the packet at the moment. */
1912 if (!ppp_mp_explode(ppp, skb))
1913 return;
1914 #endif /* CONFIG_PPP_MULTILINK */
1915
1916 ppp->xmit_pending = NULL;
1917 kfree_skb(skb);
1918 }
1919
1920 #ifdef CONFIG_PPP_MULTILINK
1921 static bool mp_protocol_compress __read_mostly = true;
1922 module_param(mp_protocol_compress, bool, 0644);
1923 MODULE_PARM_DESC(mp_protocol_compress,
1924 "compress protocol id in multilink fragments");
1925
1926 /*
1927 * Divide a packet to be transmitted into fragments and
1928 * send them out the individual links.
1929 */
ppp_mp_explode(struct ppp * ppp,struct sk_buff * skb)1930 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1931 {
1932 int len, totlen;
1933 int i, bits, hdrlen, mtu;
1934 int flen;
1935 int navail, nfree, nzero;
1936 int nbigger;
1937 int totspeed;
1938 int totfree;
1939 unsigned char *p, *q;
1940 struct list_head *list;
1941 struct channel *pch;
1942 struct sk_buff *frag;
1943 struct ppp_channel *chan;
1944
1945 totspeed = 0; /*total bitrate of the bundle*/
1946 nfree = 0; /* # channels which have no packet already queued */
1947 navail = 0; /* total # of usable channels (not deregistered) */
1948 nzero = 0; /* number of channels with zero speed associated*/
1949 totfree = 0; /*total # of channels available and
1950 *having no queued packets before
1951 *starting the fragmentation*/
1952
1953 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1954 i = 0;
1955 list_for_each_entry(pch, &ppp->channels, clist) {
1956 if (pch->chan) {
1957 pch->avail = 1;
1958 navail++;
1959 pch->speed = pch->chan->speed;
1960 } else {
1961 pch->avail = 0;
1962 }
1963 if (pch->avail) {
1964 if (skb_queue_empty(&pch->file.xq) ||
1965 !pch->had_frag) {
1966 if (pch->speed == 0)
1967 nzero++;
1968 else
1969 totspeed += pch->speed;
1970
1971 pch->avail = 2;
1972 ++nfree;
1973 ++totfree;
1974 }
1975 if (!pch->had_frag && i < ppp->nxchan)
1976 ppp->nxchan = i;
1977 }
1978 ++i;
1979 }
1980 /*
1981 * Don't start sending this packet unless at least half of
1982 * the channels are free. This gives much better TCP
1983 * performance if we have a lot of channels.
1984 */
1985 if (nfree == 0 || nfree < navail / 2)
1986 return 0; /* can't take now, leave it in xmit_pending */
1987
1988 /* Do protocol field compression */
1989 p = skb->data;
1990 len = skb->len;
1991 if (*p == 0 && mp_protocol_compress) {
1992 ++p;
1993 --len;
1994 }
1995
1996 totlen = len;
1997 nbigger = len % nfree;
1998
1999 /* skip to the channel after the one we last used
2000 and start at that one */
2001 list = &ppp->channels;
2002 for (i = 0; i < ppp->nxchan; ++i) {
2003 list = list->next;
2004 if (list == &ppp->channels) {
2005 i = 0;
2006 break;
2007 }
2008 }
2009
2010 /* create a fragment for each channel */
2011 bits = B;
2012 while (len > 0) {
2013 list = list->next;
2014 if (list == &ppp->channels) {
2015 i = 0;
2016 continue;
2017 }
2018 pch = list_entry(list, struct channel, clist);
2019 ++i;
2020 if (!pch->avail)
2021 continue;
2022
2023 /*
2024 * Skip this channel if it has a fragment pending already and
2025 * we haven't given a fragment to all of the free channels.
2026 */
2027 if (pch->avail == 1) {
2028 if (nfree > 0)
2029 continue;
2030 } else {
2031 pch->avail = 1;
2032 }
2033
2034 /* check the channel's mtu and whether it is still attached. */
2035 spin_lock(&pch->downl);
2036 if (pch->chan == NULL) {
2037 /* can't use this channel, it's being deregistered */
2038 if (pch->speed == 0)
2039 nzero--;
2040 else
2041 totspeed -= pch->speed;
2042
2043 spin_unlock(&pch->downl);
2044 pch->avail = 0;
2045 totlen = len;
2046 totfree--;
2047 nfree--;
2048 if (--navail == 0)
2049 break;
2050 continue;
2051 }
2052
2053 /*
2054 *if the channel speed is not set divide
2055 *the packet evenly among the free channels;
2056 *otherwise divide it according to the speed
2057 *of the channel we are going to transmit on
2058 */
2059 flen = len;
2060 if (nfree > 0) {
2061 if (pch->speed == 0) {
2062 flen = len/nfree;
2063 if (nbigger > 0) {
2064 flen++;
2065 nbigger--;
2066 }
2067 } else {
2068 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2069 ((totspeed*totfree)/pch->speed)) - hdrlen;
2070 if (nbigger > 0) {
2071 flen += ((totfree - nzero)*pch->speed)/totspeed;
2072 nbigger -= ((totfree - nzero)*pch->speed)/
2073 totspeed;
2074 }
2075 }
2076 nfree--;
2077 }
2078
2079 /*
2080 *check if we are on the last channel or
2081 *we exceded the length of the data to
2082 *fragment
2083 */
2084 if ((nfree <= 0) || (flen > len))
2085 flen = len;
2086 /*
2087 *it is not worth to tx on slow channels:
2088 *in that case from the resulting flen according to the
2089 *above formula will be equal or less than zero.
2090 *Skip the channel in this case
2091 */
2092 if (flen <= 0) {
2093 pch->avail = 2;
2094 spin_unlock(&pch->downl);
2095 continue;
2096 }
2097
2098 /*
2099 * hdrlen includes the 2-byte PPP protocol field, but the
2100 * MTU counts only the payload excluding the protocol field.
2101 * (RFC1661 Section 2)
2102 */
2103 mtu = pch->chan->mtu - (hdrlen - 2);
2104 if (mtu < 4)
2105 mtu = 4;
2106 if (flen > mtu)
2107 flen = mtu;
2108 if (flen == len)
2109 bits |= E;
2110 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2111 if (!frag)
2112 goto noskb;
2113 q = skb_put(frag, flen + hdrlen);
2114
2115 /* make the MP header */
2116 put_unaligned_be16(PPP_MP, q);
2117 if (ppp->flags & SC_MP_XSHORTSEQ) {
2118 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2119 q[3] = ppp->nxseq;
2120 } else {
2121 q[2] = bits;
2122 q[3] = ppp->nxseq >> 16;
2123 q[4] = ppp->nxseq >> 8;
2124 q[5] = ppp->nxseq;
2125 }
2126
2127 memcpy(q + hdrlen, p, flen);
2128
2129 /* try to send it down the channel */
2130 chan = pch->chan;
2131 if (!skb_queue_empty(&pch->file.xq) ||
2132 !chan->ops->start_xmit(chan, frag))
2133 skb_queue_tail(&pch->file.xq, frag);
2134 pch->had_frag = 1;
2135 p += flen;
2136 len -= flen;
2137 ++ppp->nxseq;
2138 bits = 0;
2139 spin_unlock(&pch->downl);
2140 }
2141 ppp->nxchan = i;
2142
2143 return 1;
2144
2145 noskb:
2146 spin_unlock(&pch->downl);
2147 if (ppp->debug & 1)
2148 netdev_err(ppp->dev, "PPP: no memory (fragment)\n");
2149 ++ppp->dev->stats.tx_errors;
2150 ++ppp->nxseq;
2151 return 1; /* abandon the frame */
2152 }
2153 #endif /* CONFIG_PPP_MULTILINK */
2154
2155 /* Try to send data out on a channel */
__ppp_channel_push(struct channel * pch)2156 static void __ppp_channel_push(struct channel *pch)
2157 {
2158 struct sk_buff *skb;
2159 struct ppp *ppp;
2160
2161 spin_lock(&pch->downl);
2162 if (pch->chan) {
2163 while (!skb_queue_empty(&pch->file.xq)) {
2164 skb = skb_dequeue(&pch->file.xq);
2165 if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2166 /* put the packet back and try again later */
2167 skb_queue_head(&pch->file.xq, skb);
2168 break;
2169 }
2170 }
2171 } else {
2172 /* channel got deregistered */
2173 skb_queue_purge(&pch->file.xq);
2174 }
2175 spin_unlock(&pch->downl);
2176 /* see if there is anything from the attached unit to be sent */
2177 if (skb_queue_empty(&pch->file.xq)) {
2178 ppp = pch->ppp;
2179 if (ppp)
2180 __ppp_xmit_process(ppp, NULL);
2181 }
2182 }
2183
ppp_channel_push(struct channel * pch)2184 static void ppp_channel_push(struct channel *pch)
2185 {
2186 read_lock_bh(&pch->upl);
2187 if (pch->ppp) {
2188 (*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2189 __ppp_channel_push(pch);
2190 (*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2191 } else {
2192 __ppp_channel_push(pch);
2193 }
2194 read_unlock_bh(&pch->upl);
2195 }
2196
2197 /*
2198 * Receive-side routines.
2199 */
2200
2201 struct ppp_mp_skb_parm {
2202 u32 sequence;
2203 u8 BEbits;
2204 };
2205 #define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
2206
2207 static inline void
ppp_do_recv(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2208 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2209 {
2210 ppp_recv_lock(ppp);
2211 if (!ppp->closing)
2212 ppp_receive_frame(ppp, skb, pch);
2213 else
2214 kfree_skb(skb);
2215 ppp_recv_unlock(ppp);
2216 }
2217
2218 /**
2219 * __ppp_decompress_proto - Decompress protocol field, slim version.
2220 * @skb: Socket buffer where protocol field should be decompressed. It must have
2221 * at least 1 byte of head room and 1 byte of linear data. First byte of
2222 * data must be a protocol field byte.
2223 *
2224 * Decompress protocol field in PPP header if it's compressed, e.g. when
2225 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2226 * length are done in this function.
2227 */
__ppp_decompress_proto(struct sk_buff * skb)2228 static void __ppp_decompress_proto(struct sk_buff *skb)
2229 {
2230 if (skb->data[0] & 0x01)
2231 *(u8 *)skb_push(skb, 1) = 0x00;
2232 }
2233
2234 /**
2235 * ppp_decompress_proto - Check skb data room and decompress protocol field.
2236 * @skb: Socket buffer where protocol field should be decompressed. First byte
2237 * of data must be a protocol field byte.
2238 *
2239 * Decompress protocol field in PPP header if it's compressed, e.g. when
2240 * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2241 * sure that skb data room is sufficient for Protocol field, before and after
2242 * decompression.
2243 *
2244 * Return: true - decompressed successfully, false - not enough room in skb.
2245 */
ppp_decompress_proto(struct sk_buff * skb)2246 static bool ppp_decompress_proto(struct sk_buff *skb)
2247 {
2248 /* At least one byte should be present (if protocol is compressed) */
2249 if (!pskb_may_pull(skb, 1))
2250 return false;
2251
2252 __ppp_decompress_proto(skb);
2253
2254 /* Protocol field should occupy 2 bytes when not compressed */
2255 return pskb_may_pull(skb, 2);
2256 }
2257
2258 /* Attempt to handle a frame via. a bridged channel, if one exists.
2259 * If the channel is bridged, the frame is consumed by the bridge.
2260 * If not, the caller must handle the frame by normal recv mechanisms.
2261 * Returns true if the frame is consumed, false otherwise.
2262 */
ppp_channel_bridge_input(struct channel * pch,struct sk_buff * skb)2263 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2264 {
2265 struct channel *pchb;
2266
2267 rcu_read_lock();
2268 pchb = rcu_dereference(pch->bridge);
2269 if (!pchb)
2270 goto out_rcu;
2271
2272 spin_lock(&pchb->downl);
2273 if (!pchb->chan) {
2274 /* channel got unregistered */
2275 kfree_skb(skb);
2276 goto outl;
2277 }
2278
2279 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2280 if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2281 kfree_skb(skb);
2282
2283 outl:
2284 spin_unlock(&pchb->downl);
2285 out_rcu:
2286 rcu_read_unlock();
2287
2288 /* If pchb is set then we've consumed the packet */
2289 return !!pchb;
2290 }
2291
2292 void
ppp_input(struct ppp_channel * chan,struct sk_buff * skb)2293 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2294 {
2295 struct channel *pch = chan->ppp;
2296 int proto;
2297
2298 if (!pch) {
2299 kfree_skb(skb);
2300 return;
2301 }
2302
2303 /* If the channel is bridged, transmit via. bridge */
2304 if (ppp_channel_bridge_input(pch, skb))
2305 return;
2306
2307 read_lock_bh(&pch->upl);
2308 if (!ppp_decompress_proto(skb)) {
2309 kfree_skb(skb);
2310 if (pch->ppp) {
2311 ++pch->ppp->dev->stats.rx_length_errors;
2312 ppp_receive_error(pch->ppp);
2313 }
2314 goto done;
2315 }
2316
2317 proto = PPP_PROTO(skb);
2318 if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2319 /* put it on the channel queue */
2320 skb_queue_tail(&pch->file.rq, skb);
2321 /* drop old frames if queue too long */
2322 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2323 (skb = skb_dequeue(&pch->file.rq)))
2324 kfree_skb(skb);
2325 wake_up_interruptible(&pch->file.rwait);
2326 } else {
2327 ppp_do_recv(pch->ppp, skb, pch);
2328 }
2329
2330 done:
2331 read_unlock_bh(&pch->upl);
2332 }
2333
2334 /* Put a 0-length skb in the receive queue as an error indication */
2335 void
ppp_input_error(struct ppp_channel * chan,int code)2336 ppp_input_error(struct ppp_channel *chan, int code)
2337 {
2338 struct channel *pch = chan->ppp;
2339 struct sk_buff *skb;
2340
2341 if (!pch)
2342 return;
2343
2344 read_lock_bh(&pch->upl);
2345 if (pch->ppp) {
2346 skb = alloc_skb(0, GFP_ATOMIC);
2347 if (skb) {
2348 skb->len = 0; /* probably unnecessary */
2349 skb->cb[0] = code;
2350 ppp_do_recv(pch->ppp, skb, pch);
2351 }
2352 }
2353 read_unlock_bh(&pch->upl);
2354 }
2355
2356 /*
2357 * We come in here to process a received frame.
2358 * The receive side of the ppp unit is locked.
2359 */
2360 static void
ppp_receive_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2361 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2362 {
2363 /* note: a 0-length skb is used as an error indication */
2364 if (skb->len > 0) {
2365 skb_checksum_complete_unset(skb);
2366 #ifdef CONFIG_PPP_MULTILINK
2367 /* XXX do channel-level decompression here */
2368 if (PPP_PROTO(skb) == PPP_MP)
2369 ppp_receive_mp_frame(ppp, skb, pch);
2370 else
2371 #endif /* CONFIG_PPP_MULTILINK */
2372 ppp_receive_nonmp_frame(ppp, skb);
2373 } else {
2374 kfree_skb(skb);
2375 ppp_receive_error(ppp);
2376 }
2377 }
2378
2379 static void
ppp_receive_error(struct ppp * ppp)2380 ppp_receive_error(struct ppp *ppp)
2381 {
2382 ++ppp->dev->stats.rx_errors;
2383 if (ppp->vj)
2384 slhc_toss(ppp->vj);
2385 }
2386
2387 static void
ppp_receive_nonmp_frame(struct ppp * ppp,struct sk_buff * skb)2388 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2389 {
2390 struct sk_buff *ns;
2391 int proto, len, npi;
2392
2393 /*
2394 * Decompress the frame, if compressed.
2395 * Note that some decompressors need to see uncompressed frames
2396 * that come in as well as compressed frames.
2397 */
2398 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2399 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2400 skb = ppp_decompress_frame(ppp, skb);
2401
2402 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2403 goto err;
2404
2405 /* At this point the "Protocol" field MUST be decompressed, either in
2406 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2407 */
2408 proto = PPP_PROTO(skb);
2409 switch (proto) {
2410 case PPP_VJC_COMP:
2411 /* decompress VJ compressed packets */
2412 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2413 goto err;
2414
2415 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2416 /* copy to a new sk_buff with more tailroom */
2417 ns = dev_alloc_skb(skb->len + 128);
2418 if (!ns) {
2419 netdev_err(ppp->dev, "PPP: no memory "
2420 "(VJ decomp)\n");
2421 goto err;
2422 }
2423 skb_reserve(ns, 2);
2424 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2425 consume_skb(skb);
2426 skb = ns;
2427 }
2428 else
2429 skb->ip_summed = CHECKSUM_NONE;
2430
2431 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2432 if (len <= 0) {
2433 netdev_printk(KERN_DEBUG, ppp->dev,
2434 "PPP: VJ decompression error\n");
2435 goto err;
2436 }
2437 len += 2;
2438 if (len > skb->len)
2439 skb_put(skb, len - skb->len);
2440 else if (len < skb->len)
2441 skb_trim(skb, len);
2442 proto = PPP_IP;
2443 break;
2444
2445 case PPP_VJC_UNCOMP:
2446 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2447 goto err;
2448
2449 /* Until we fix the decompressor need to make sure
2450 * data portion is linear.
2451 */
2452 if (!pskb_may_pull(skb, skb->len))
2453 goto err;
2454
2455 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2456 netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
2457 goto err;
2458 }
2459 proto = PPP_IP;
2460 break;
2461
2462 case PPP_CCP:
2463 ppp_ccp_peek(ppp, skb, 1);
2464 break;
2465 }
2466
2467 ++ppp->stats64.rx_packets;
2468 ppp->stats64.rx_bytes += skb->len - 2;
2469
2470 npi = proto_to_npindex(proto);
2471 if (npi < 0) {
2472 /* control or unknown frame - pass it to pppd */
2473 skb_queue_tail(&ppp->file.rq, skb);
2474 /* limit queue length by dropping old frames */
2475 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2476 (skb = skb_dequeue(&ppp->file.rq)))
2477 kfree_skb(skb);
2478 /* wake up any process polling or blocking on read */
2479 wake_up_interruptible(&ppp->file.rwait);
2480
2481 } else {
2482 /* network protocol frame - give it to the kernel */
2483
2484 #ifdef CONFIG_PPP_FILTER
2485 /* check if the packet passes the pass and active filters */
2486 /* the filter instructions are constructed assuming
2487 a four-byte PPP header on each packet */
2488 if (ppp->pass_filter || ppp->active_filter) {
2489 if (skb_unclone(skb, GFP_ATOMIC))
2490 goto err;
2491
2492 *(u8 *)skb_push(skb, 2) = 0;
2493 if (ppp->pass_filter &&
2494 bpf_prog_run(ppp->pass_filter, skb) == 0) {
2495 if (ppp->debug & 1)
2496 netdev_printk(KERN_DEBUG, ppp->dev,
2497 "PPP: inbound frame "
2498 "not passed\n");
2499 kfree_skb(skb);
2500 return;
2501 }
2502 if (!(ppp->active_filter &&
2503 bpf_prog_run(ppp->active_filter, skb) == 0))
2504 ppp->last_recv = jiffies;
2505 __skb_pull(skb, 2);
2506 } else
2507 #endif /* CONFIG_PPP_FILTER */
2508 ppp->last_recv = jiffies;
2509
2510 if ((ppp->dev->flags & IFF_UP) == 0 ||
2511 ppp->npmode[npi] != NPMODE_PASS) {
2512 kfree_skb(skb);
2513 } else {
2514 /* chop off protocol */
2515 skb_pull_rcsum(skb, 2);
2516 skb->dev = ppp->dev;
2517 skb->protocol = htons(npindex_to_ethertype[npi]);
2518 skb_reset_mac_header(skb);
2519 skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2520 dev_net(ppp->dev)));
2521 netif_rx(skb);
2522 }
2523 }
2524 return;
2525
2526 err:
2527 kfree_skb(skb);
2528 ppp_receive_error(ppp);
2529 }
2530
2531 static struct sk_buff *
ppp_decompress_frame(struct ppp * ppp,struct sk_buff * skb)2532 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2533 {
2534 int proto = PPP_PROTO(skb);
2535 struct sk_buff *ns;
2536 int len;
2537
2538 /* Until we fix all the decompressor's need to make sure
2539 * data portion is linear.
2540 */
2541 if (!pskb_may_pull(skb, skb->len))
2542 goto err;
2543
2544 if (proto == PPP_COMP) {
2545 int obuff_size;
2546
2547 switch(ppp->rcomp->compress_proto) {
2548 case CI_MPPE:
2549 obuff_size = ppp->mru + PPP_HDRLEN + 1;
2550 break;
2551 default:
2552 obuff_size = ppp->mru + PPP_HDRLEN;
2553 break;
2554 }
2555
2556 ns = dev_alloc_skb(obuff_size);
2557 if (!ns) {
2558 netdev_err(ppp->dev, "ppp_decompress_frame: "
2559 "no memory\n");
2560 goto err;
2561 }
2562 /* the decompressor still expects the A/C bytes in the hdr */
2563 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2564 skb->len + 2, ns->data, obuff_size);
2565 if (len < 0) {
2566 /* Pass the compressed frame to pppd as an
2567 error indication. */
2568 if (len == DECOMP_FATALERROR)
2569 ppp->rstate |= SC_DC_FERROR;
2570 kfree_skb(ns);
2571 goto err;
2572 }
2573
2574 consume_skb(skb);
2575 skb = ns;
2576 skb_put(skb, len);
2577 skb_pull(skb, 2); /* pull off the A/C bytes */
2578
2579 /* Don't call __ppp_decompress_proto() here, but instead rely on
2580 * corresponding algo (mppe/bsd/deflate) to decompress it.
2581 */
2582 } else {
2583 /* Uncompressed frame - pass to decompressor so it
2584 can update its dictionary if necessary. */
2585 if (ppp->rcomp->incomp)
2586 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2587 skb->len + 2);
2588 }
2589
2590 return skb;
2591
2592 err:
2593 ppp->rstate |= SC_DC_ERROR;
2594 ppp_receive_error(ppp);
2595 return skb;
2596 }
2597
2598 #ifdef CONFIG_PPP_MULTILINK
2599 /*
2600 * Receive a multilink frame.
2601 * We put it on the reconstruction queue and then pull off
2602 * as many completed frames as we can.
2603 */
2604 static void
ppp_receive_mp_frame(struct ppp * ppp,struct sk_buff * skb,struct channel * pch)2605 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2606 {
2607 u32 mask, seq;
2608 struct channel *ch;
2609 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2610
2611 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2612 goto err; /* no good, throw it away */
2613
2614 /* Decode sequence number and begin/end bits */
2615 if (ppp->flags & SC_MP_SHORTSEQ) {
2616 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2617 mask = 0xfff;
2618 } else {
2619 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2620 mask = 0xffffff;
2621 }
2622 PPP_MP_CB(skb)->BEbits = skb->data[2];
2623 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */
2624
2625 /*
2626 * Do protocol ID decompression on the first fragment of each packet.
2627 * We have to do that here, because ppp_receive_nonmp_frame() expects
2628 * decompressed protocol field.
2629 */
2630 if (PPP_MP_CB(skb)->BEbits & B)
2631 __ppp_decompress_proto(skb);
2632
2633 /*
2634 * Expand sequence number to 32 bits, making it as close
2635 * as possible to ppp->minseq.
2636 */
2637 seq |= ppp->minseq & ~mask;
2638 if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2639 seq += mask + 1;
2640 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2641 seq -= mask + 1; /* should never happen */
2642 PPP_MP_CB(skb)->sequence = seq;
2643 pch->lastseq = seq;
2644
2645 /*
2646 * If this packet comes before the next one we were expecting,
2647 * drop it.
2648 */
2649 if (seq_before(seq, ppp->nextseq)) {
2650 kfree_skb(skb);
2651 ++ppp->dev->stats.rx_dropped;
2652 ppp_receive_error(ppp);
2653 return;
2654 }
2655
2656 /*
2657 * Reevaluate minseq, the minimum over all channels of the
2658 * last sequence number received on each channel. Because of
2659 * the increasing sequence number rule, we know that any fragment
2660 * before `minseq' which hasn't arrived is never going to arrive.
2661 * The list of channels can't change because we have the receive
2662 * side of the ppp unit locked.
2663 */
2664 list_for_each_entry(ch, &ppp->channels, clist) {
2665 if (seq_before(ch->lastseq, seq))
2666 seq = ch->lastseq;
2667 }
2668 if (seq_before(ppp->minseq, seq))
2669 ppp->minseq = seq;
2670
2671 /* Put the fragment on the reconstruction queue */
2672 ppp_mp_insert(ppp, skb);
2673
2674 /* If the queue is getting long, don't wait any longer for packets
2675 before the start of the queue. */
2676 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2677 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2678 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2679 ppp->minseq = PPP_MP_CB(mskb)->sequence;
2680 }
2681
2682 /* Pull completed packets off the queue and receive them. */
2683 while ((skb = ppp_mp_reconstruct(ppp))) {
2684 if (pskb_may_pull(skb, 2))
2685 ppp_receive_nonmp_frame(ppp, skb);
2686 else {
2687 ++ppp->dev->stats.rx_length_errors;
2688 kfree_skb(skb);
2689 ppp_receive_error(ppp);
2690 }
2691 }
2692
2693 return;
2694
2695 err:
2696 kfree_skb(skb);
2697 ppp_receive_error(ppp);
2698 }
2699
2700 /*
2701 * Insert a fragment on the MP reconstruction queue.
2702 * The queue is ordered by increasing sequence number.
2703 */
2704 static void
ppp_mp_insert(struct ppp * ppp,struct sk_buff * skb)2705 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2706 {
2707 struct sk_buff *p;
2708 struct sk_buff_head *list = &ppp->mrq;
2709 u32 seq = PPP_MP_CB(skb)->sequence;
2710
2711 /* N.B. we don't need to lock the list lock because we have the
2712 ppp unit receive-side lock. */
2713 skb_queue_walk(list, p) {
2714 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2715 break;
2716 }
2717 __skb_queue_before(list, p, skb);
2718 }
2719
2720 /*
2721 * Reconstruct a packet from the MP fragment queue.
2722 * We go through increasing sequence numbers until we find a
2723 * complete packet, or we get to the sequence number for a fragment
2724 * which hasn't arrived but might still do so.
2725 */
2726 static struct sk_buff *
ppp_mp_reconstruct(struct ppp * ppp)2727 ppp_mp_reconstruct(struct ppp *ppp)
2728 {
2729 u32 seq = ppp->nextseq;
2730 u32 minseq = ppp->minseq;
2731 struct sk_buff_head *list = &ppp->mrq;
2732 struct sk_buff *p, *tmp;
2733 struct sk_buff *head, *tail;
2734 struct sk_buff *skb = NULL;
2735 int lost = 0, len = 0;
2736
2737 if (ppp->mrru == 0) /* do nothing until mrru is set */
2738 return NULL;
2739 head = __skb_peek(list);
2740 tail = NULL;
2741 skb_queue_walk_safe(list, p, tmp) {
2742 again:
2743 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2744 /* this can't happen, anyway ignore the skb */
2745 netdev_err(ppp->dev, "ppp_mp_reconstruct bad "
2746 "seq %u < %u\n",
2747 PPP_MP_CB(p)->sequence, seq);
2748 __skb_unlink(p, list);
2749 kfree_skb(p);
2750 continue;
2751 }
2752 if (PPP_MP_CB(p)->sequence != seq) {
2753 u32 oldseq;
2754 /* Fragment `seq' is missing. If it is after
2755 minseq, it might arrive later, so stop here. */
2756 if (seq_after(seq, minseq))
2757 break;
2758 /* Fragment `seq' is lost, keep going. */
2759 lost = 1;
2760 oldseq = seq;
2761 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2762 minseq + 1: PPP_MP_CB(p)->sequence;
2763
2764 if (ppp->debug & 1)
2765 netdev_printk(KERN_DEBUG, ppp->dev,
2766 "lost frag %u..%u\n",
2767 oldseq, seq-1);
2768
2769 goto again;
2770 }
2771
2772 /*
2773 * At this point we know that all the fragments from
2774 * ppp->nextseq to seq are either present or lost.
2775 * Also, there are no complete packets in the queue
2776 * that have no missing fragments and end before this
2777 * fragment.
2778 */
2779
2780 /* B bit set indicates this fragment starts a packet */
2781 if (PPP_MP_CB(p)->BEbits & B) {
2782 head = p;
2783 lost = 0;
2784 len = 0;
2785 }
2786
2787 len += p->len;
2788
2789 /* Got a complete packet yet? */
2790 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2791 (PPP_MP_CB(head)->BEbits & B)) {
2792 if (len > ppp->mrru + 2) {
2793 ++ppp->dev->stats.rx_length_errors;
2794 netdev_printk(KERN_DEBUG, ppp->dev,
2795 "PPP: reconstructed packet"
2796 " is too long (%d)\n", len);
2797 } else {
2798 tail = p;
2799 break;
2800 }
2801 ppp->nextseq = seq + 1;
2802 }
2803
2804 /*
2805 * If this is the ending fragment of a packet,
2806 * and we haven't found a complete valid packet yet,
2807 * we can discard up to and including this fragment.
2808 */
2809 if (PPP_MP_CB(p)->BEbits & E) {
2810 struct sk_buff *tmp2;
2811
2812 skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2813 if (ppp->debug & 1)
2814 netdev_printk(KERN_DEBUG, ppp->dev,
2815 "discarding frag %u\n",
2816 PPP_MP_CB(p)->sequence);
2817 __skb_unlink(p, list);
2818 kfree_skb(p);
2819 }
2820 head = skb_peek(list);
2821 if (!head)
2822 break;
2823 }
2824 ++seq;
2825 }
2826
2827 /* If we have a complete packet, copy it all into one skb. */
2828 if (tail != NULL) {
2829 /* If we have discarded any fragments,
2830 signal a receive error. */
2831 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2832 skb_queue_walk_safe(list, p, tmp) {
2833 if (p == head)
2834 break;
2835 if (ppp->debug & 1)
2836 netdev_printk(KERN_DEBUG, ppp->dev,
2837 "discarding frag %u\n",
2838 PPP_MP_CB(p)->sequence);
2839 __skb_unlink(p, list);
2840 kfree_skb(p);
2841 }
2842
2843 if (ppp->debug & 1)
2844 netdev_printk(KERN_DEBUG, ppp->dev,
2845 " missed pkts %u..%u\n",
2846 ppp->nextseq,
2847 PPP_MP_CB(head)->sequence-1);
2848 ++ppp->dev->stats.rx_dropped;
2849 ppp_receive_error(ppp);
2850 }
2851
2852 skb = head;
2853 if (head != tail) {
2854 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2855 p = skb_queue_next(list, head);
2856 __skb_unlink(skb, list);
2857 skb_queue_walk_from_safe(list, p, tmp) {
2858 __skb_unlink(p, list);
2859 *fragpp = p;
2860 p->next = NULL;
2861 fragpp = &p->next;
2862
2863 skb->len += p->len;
2864 skb->data_len += p->len;
2865 skb->truesize += p->truesize;
2866
2867 if (p == tail)
2868 break;
2869 }
2870 } else {
2871 __skb_unlink(skb, list);
2872 }
2873
2874 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2875 }
2876
2877 return skb;
2878 }
2879 #endif /* CONFIG_PPP_MULTILINK */
2880
2881 /*
2882 * Channel interface.
2883 */
2884
2885 /* Create a new, unattached ppp channel. */
ppp_register_channel(struct ppp_channel * chan)2886 int ppp_register_channel(struct ppp_channel *chan)
2887 {
2888 return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2889 }
2890
2891 /* Create a new, unattached ppp channel for specified net. */
ppp_register_net_channel(struct net * net,struct ppp_channel * chan)2892 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2893 {
2894 struct channel *pch;
2895 struct ppp_net *pn;
2896
2897 pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2898 if (!pch)
2899 return -ENOMEM;
2900
2901 pn = ppp_pernet(net);
2902
2903 pch->ppp = NULL;
2904 pch->chan = chan;
2905 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2906 chan->ppp = pch;
2907 init_ppp_file(&pch->file, CHANNEL);
2908 pch->file.hdrlen = chan->hdrlen;
2909 #ifdef CONFIG_PPP_MULTILINK
2910 pch->lastseq = -1;
2911 #endif /* CONFIG_PPP_MULTILINK */
2912 init_rwsem(&pch->chan_sem);
2913 spin_lock_init(&pch->downl);
2914 rwlock_init(&pch->upl);
2915
2916 spin_lock_bh(&pn->all_channels_lock);
2917 pch->file.index = ++pn->last_channel_index;
2918 list_add(&pch->list, &pn->new_channels);
2919 atomic_inc(&channel_count);
2920 spin_unlock_bh(&pn->all_channels_lock);
2921
2922 return 0;
2923 }
2924
2925 /*
2926 * Return the index of a channel.
2927 */
ppp_channel_index(struct ppp_channel * chan)2928 int ppp_channel_index(struct ppp_channel *chan)
2929 {
2930 struct channel *pch = chan->ppp;
2931
2932 if (pch)
2933 return pch->file.index;
2934 return -1;
2935 }
2936
2937 /*
2938 * Return the PPP unit number to which a channel is connected.
2939 */
ppp_unit_number(struct ppp_channel * chan)2940 int ppp_unit_number(struct ppp_channel *chan)
2941 {
2942 struct channel *pch = chan->ppp;
2943 int unit = -1;
2944
2945 if (pch) {
2946 read_lock_bh(&pch->upl);
2947 if (pch->ppp)
2948 unit = pch->ppp->file.index;
2949 read_unlock_bh(&pch->upl);
2950 }
2951 return unit;
2952 }
2953
2954 /*
2955 * Return the PPP device interface name of a channel.
2956 */
ppp_dev_name(struct ppp_channel * chan)2957 char *ppp_dev_name(struct ppp_channel *chan)
2958 {
2959 struct channel *pch = chan->ppp;
2960 char *name = NULL;
2961
2962 if (pch) {
2963 read_lock_bh(&pch->upl);
2964 if (pch->ppp && pch->ppp->dev)
2965 name = pch->ppp->dev->name;
2966 read_unlock_bh(&pch->upl);
2967 }
2968 return name;
2969 }
2970
2971
2972 /*
2973 * Disconnect a channel from the generic layer.
2974 * This must be called in process context.
2975 */
2976 void
ppp_unregister_channel(struct ppp_channel * chan)2977 ppp_unregister_channel(struct ppp_channel *chan)
2978 {
2979 struct channel *pch = chan->ppp;
2980 struct ppp_net *pn;
2981
2982 if (!pch)
2983 return; /* should never happen */
2984
2985 chan->ppp = NULL;
2986
2987 /*
2988 * This ensures that we have returned from any calls into
2989 * the channel's start_xmit or ioctl routine before we proceed.
2990 */
2991 down_write(&pch->chan_sem);
2992 spin_lock_bh(&pch->downl);
2993 pch->chan = NULL;
2994 spin_unlock_bh(&pch->downl);
2995 up_write(&pch->chan_sem);
2996 ppp_disconnect_channel(pch);
2997
2998 pn = ppp_pernet(pch->chan_net);
2999 spin_lock_bh(&pn->all_channels_lock);
3000 list_del(&pch->list);
3001 spin_unlock_bh(&pn->all_channels_lock);
3002
3003 ppp_unbridge_channels(pch);
3004
3005 pch->file.dead = 1;
3006 wake_up_interruptible(&pch->file.rwait);
3007
3008 if (refcount_dec_and_test(&pch->file.refcnt))
3009 ppp_destroy_channel(pch);
3010 }
3011
3012 /*
3013 * Callback from a channel when it can accept more to transmit.
3014 * This should be called at BH/softirq level, not interrupt level.
3015 */
3016 void
ppp_output_wakeup(struct ppp_channel * chan)3017 ppp_output_wakeup(struct ppp_channel *chan)
3018 {
3019 struct channel *pch = chan->ppp;
3020
3021 if (!pch)
3022 return;
3023 ppp_channel_push(pch);
3024 }
3025
3026 /*
3027 * Compression control.
3028 */
3029
3030 /* Process the PPPIOCSCOMPRESS ioctl. */
3031 static int
ppp_set_compress(struct ppp * ppp,struct ppp_option_data * data)3032 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3033 {
3034 int err = -EFAULT;
3035 struct compressor *cp, *ocomp;
3036 void *state, *ostate;
3037 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3038
3039 if (data->length > CCP_MAX_OPTION_LENGTH)
3040 goto out;
3041 if (copy_from_user(ccp_option, data->ptr, data->length))
3042 goto out;
3043
3044 err = -EINVAL;
3045 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3046 goto out;
3047
3048 cp = try_then_request_module(
3049 find_compressor(ccp_option[0]),
3050 "ppp-compress-%d", ccp_option[0]);
3051 if (!cp)
3052 goto out;
3053
3054 err = -ENOBUFS;
3055 if (data->transmit) {
3056 state = cp->comp_alloc(ccp_option, data->length);
3057 if (state) {
3058 ppp_xmit_lock(ppp);
3059 ppp->xstate &= ~SC_COMP_RUN;
3060 ocomp = ppp->xcomp;
3061 ostate = ppp->xc_state;
3062 ppp->xcomp = cp;
3063 ppp->xc_state = state;
3064 ppp_xmit_unlock(ppp);
3065 if (ostate) {
3066 ocomp->comp_free(ostate);
3067 module_put(ocomp->owner);
3068 }
3069 err = 0;
3070 } else
3071 module_put(cp->owner);
3072
3073 } else {
3074 state = cp->decomp_alloc(ccp_option, data->length);
3075 if (state) {
3076 ppp_recv_lock(ppp);
3077 ppp->rstate &= ~SC_DECOMP_RUN;
3078 ocomp = ppp->rcomp;
3079 ostate = ppp->rc_state;
3080 ppp->rcomp = cp;
3081 ppp->rc_state = state;
3082 ppp_recv_unlock(ppp);
3083 if (ostate) {
3084 ocomp->decomp_free(ostate);
3085 module_put(ocomp->owner);
3086 }
3087 err = 0;
3088 } else
3089 module_put(cp->owner);
3090 }
3091
3092 out:
3093 return err;
3094 }
3095
3096 /*
3097 * Look at a CCP packet and update our state accordingly.
3098 * We assume the caller has the xmit or recv path locked.
3099 */
3100 static void
ppp_ccp_peek(struct ppp * ppp,struct sk_buff * skb,int inbound)3101 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3102 {
3103 unsigned char *dp;
3104 int len;
3105
3106 if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3107 return; /* no header */
3108 dp = skb->data + 2;
3109
3110 switch (CCP_CODE(dp)) {
3111 case CCP_CONFREQ:
3112
3113 /* A ConfReq starts negotiation of compression
3114 * in one direction of transmission,
3115 * and hence brings it down...but which way?
3116 *
3117 * Remember:
3118 * A ConfReq indicates what the sender would like to receive
3119 */
3120 if(inbound)
3121 /* He is proposing what I should send */
3122 ppp->xstate &= ~SC_COMP_RUN;
3123 else
3124 /* I am proposing to what he should send */
3125 ppp->rstate &= ~SC_DECOMP_RUN;
3126
3127 break;
3128
3129 case CCP_TERMREQ:
3130 case CCP_TERMACK:
3131 /*
3132 * CCP is going down, both directions of transmission
3133 */
3134 ppp->rstate &= ~SC_DECOMP_RUN;
3135 ppp->xstate &= ~SC_COMP_RUN;
3136 break;
3137
3138 case CCP_CONFACK:
3139 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3140 break;
3141 len = CCP_LENGTH(dp);
3142 if (!pskb_may_pull(skb, len + 2))
3143 return; /* too short */
3144 dp += CCP_HDRLEN;
3145 len -= CCP_HDRLEN;
3146 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3147 break;
3148 if (inbound) {
3149 /* we will start receiving compressed packets */
3150 if (!ppp->rc_state)
3151 break;
3152 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3153 ppp->file.index, 0, ppp->mru, ppp->debug)) {
3154 ppp->rstate |= SC_DECOMP_RUN;
3155 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3156 }
3157 } else {
3158 /* we will soon start sending compressed packets */
3159 if (!ppp->xc_state)
3160 break;
3161 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3162 ppp->file.index, 0, ppp->debug))
3163 ppp->xstate |= SC_COMP_RUN;
3164 }
3165 break;
3166
3167 case CCP_RESETACK:
3168 /* reset the [de]compressor */
3169 if ((ppp->flags & SC_CCP_UP) == 0)
3170 break;
3171 if (inbound) {
3172 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3173 ppp->rcomp->decomp_reset(ppp->rc_state);
3174 ppp->rstate &= ~SC_DC_ERROR;
3175 }
3176 } else {
3177 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3178 ppp->xcomp->comp_reset(ppp->xc_state);
3179 }
3180 break;
3181 }
3182 }
3183
3184 /* Free up compression resources. */
3185 static void
ppp_ccp_closed(struct ppp * ppp)3186 ppp_ccp_closed(struct ppp *ppp)
3187 {
3188 void *xstate, *rstate;
3189 struct compressor *xcomp, *rcomp;
3190
3191 ppp_lock(ppp);
3192 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3193 ppp->xstate = 0;
3194 xcomp = ppp->xcomp;
3195 xstate = ppp->xc_state;
3196 ppp->xc_state = NULL;
3197 ppp->rstate = 0;
3198 rcomp = ppp->rcomp;
3199 rstate = ppp->rc_state;
3200 ppp->rc_state = NULL;
3201 ppp_unlock(ppp);
3202
3203 if (xstate) {
3204 xcomp->comp_free(xstate);
3205 module_put(xcomp->owner);
3206 }
3207 if (rstate) {
3208 rcomp->decomp_free(rstate);
3209 module_put(rcomp->owner);
3210 }
3211 }
3212
3213 /* List of compressors. */
3214 static LIST_HEAD(compressor_list);
3215 static DEFINE_SPINLOCK(compressor_list_lock);
3216
3217 struct compressor_entry {
3218 struct list_head list;
3219 struct compressor *comp;
3220 };
3221
3222 static struct compressor_entry *
find_comp_entry(int proto)3223 find_comp_entry(int proto)
3224 {
3225 struct compressor_entry *ce;
3226
3227 list_for_each_entry(ce, &compressor_list, list) {
3228 if (ce->comp->compress_proto == proto)
3229 return ce;
3230 }
3231 return NULL;
3232 }
3233
3234 /* Register a compressor */
3235 int
ppp_register_compressor(struct compressor * cp)3236 ppp_register_compressor(struct compressor *cp)
3237 {
3238 struct compressor_entry *ce;
3239 int ret;
3240 spin_lock(&compressor_list_lock);
3241 ret = -EEXIST;
3242 if (find_comp_entry(cp->compress_proto))
3243 goto out;
3244 ret = -ENOMEM;
3245 ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3246 if (!ce)
3247 goto out;
3248 ret = 0;
3249 ce->comp = cp;
3250 list_add(&ce->list, &compressor_list);
3251 out:
3252 spin_unlock(&compressor_list_lock);
3253 return ret;
3254 }
3255
3256 /* Unregister a compressor */
3257 void
ppp_unregister_compressor(struct compressor * cp)3258 ppp_unregister_compressor(struct compressor *cp)
3259 {
3260 struct compressor_entry *ce;
3261
3262 spin_lock(&compressor_list_lock);
3263 ce = find_comp_entry(cp->compress_proto);
3264 if (ce && ce->comp == cp) {
3265 list_del(&ce->list);
3266 kfree(ce);
3267 }
3268 spin_unlock(&compressor_list_lock);
3269 }
3270
3271 /* Find a compressor. */
3272 static struct compressor *
find_compressor(int type)3273 find_compressor(int type)
3274 {
3275 struct compressor_entry *ce;
3276 struct compressor *cp = NULL;
3277
3278 spin_lock(&compressor_list_lock);
3279 ce = find_comp_entry(type);
3280 if (ce) {
3281 cp = ce->comp;
3282 if (!try_module_get(cp->owner))
3283 cp = NULL;
3284 }
3285 spin_unlock(&compressor_list_lock);
3286 return cp;
3287 }
3288
3289 /*
3290 * Miscelleneous stuff.
3291 */
3292
3293 static void
ppp_get_stats(struct ppp * ppp,struct ppp_stats * st)3294 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3295 {
3296 struct slcompress *vj = ppp->vj;
3297
3298 memset(st, 0, sizeof(*st));
3299 st->p.ppp_ipackets = ppp->stats64.rx_packets;
3300 st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3301 st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3302 st->p.ppp_opackets = ppp->stats64.tx_packets;
3303 st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3304 st->p.ppp_obytes = ppp->stats64.tx_bytes;
3305 if (!vj)
3306 return;
3307 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3308 st->vj.vjs_compressed = vj->sls_o_compressed;
3309 st->vj.vjs_searches = vj->sls_o_searches;
3310 st->vj.vjs_misses = vj->sls_o_misses;
3311 st->vj.vjs_errorin = vj->sls_i_error;
3312 st->vj.vjs_tossed = vj->sls_i_tossed;
3313 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3314 st->vj.vjs_compressedin = vj->sls_i_compressed;
3315 }
3316
3317 /*
3318 * Stuff for handling the lists of ppp units and channels
3319 * and for initialization.
3320 */
3321
3322 /*
3323 * Create a new ppp interface unit. Fails if it can't allocate memory
3324 * or if there is already a unit with the requested number.
3325 * unit == -1 means allocate a new number.
3326 */
ppp_create_interface(struct net * net,struct file * file,int * unit)3327 static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3328 {
3329 struct ppp_config conf = {
3330 .file = file,
3331 .unit = *unit,
3332 .ifname_is_set = false,
3333 };
3334 struct net_device *dev;
3335 struct ppp *ppp;
3336 int err;
3337
3338 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3339 if (!dev) {
3340 err = -ENOMEM;
3341 goto err;
3342 }
3343 dev_net_set(dev, net);
3344 dev->rtnl_link_ops = &ppp_link_ops;
3345
3346 rtnl_lock();
3347
3348 err = ppp_dev_configure(net, dev, &conf);
3349 if (err < 0)
3350 goto err_dev;
3351 ppp = netdev_priv(dev);
3352 *unit = ppp->file.index;
3353
3354 rtnl_unlock();
3355
3356 return 0;
3357
3358 err_dev:
3359 rtnl_unlock();
3360 free_netdev(dev);
3361 err:
3362 return err;
3363 }
3364
3365 /*
3366 * Initialize a ppp_file structure.
3367 */
3368 static void
init_ppp_file(struct ppp_file * pf,int kind)3369 init_ppp_file(struct ppp_file *pf, int kind)
3370 {
3371 pf->kind = kind;
3372 skb_queue_head_init(&pf->xq);
3373 skb_queue_head_init(&pf->rq);
3374 refcount_set(&pf->refcnt, 1);
3375 init_waitqueue_head(&pf->rwait);
3376 }
3377
3378 /*
3379 * Free the memory used by a ppp unit. This is only called once
3380 * there are no channels connected to the unit and no file structs
3381 * that reference the unit.
3382 */
ppp_destroy_interface(struct ppp * ppp)3383 static void ppp_destroy_interface(struct ppp *ppp)
3384 {
3385 atomic_dec(&ppp_unit_count);
3386
3387 if (!ppp->file.dead || ppp->n_channels) {
3388 /* "can't happen" */
3389 netdev_err(ppp->dev, "ppp: destroying ppp struct %p "
3390 "but dead=%d n_channels=%d !\n",
3391 ppp, ppp->file.dead, ppp->n_channels);
3392 return;
3393 }
3394
3395 ppp_ccp_closed(ppp);
3396 if (ppp->vj) {
3397 slhc_free(ppp->vj);
3398 ppp->vj = NULL;
3399 }
3400 skb_queue_purge(&ppp->file.xq);
3401 skb_queue_purge(&ppp->file.rq);
3402 #ifdef CONFIG_PPP_MULTILINK
3403 skb_queue_purge(&ppp->mrq);
3404 #endif /* CONFIG_PPP_MULTILINK */
3405 #ifdef CONFIG_PPP_FILTER
3406 if (ppp->pass_filter) {
3407 bpf_prog_destroy(ppp->pass_filter);
3408 ppp->pass_filter = NULL;
3409 }
3410
3411 if (ppp->active_filter) {
3412 bpf_prog_destroy(ppp->active_filter);
3413 ppp->active_filter = NULL;
3414 }
3415 #endif /* CONFIG_PPP_FILTER */
3416
3417 kfree_skb(ppp->xmit_pending);
3418 free_percpu(ppp->xmit_recursion);
3419
3420 free_netdev(ppp->dev);
3421 }
3422
3423 /*
3424 * Locate an existing ppp unit.
3425 * The caller should have locked the all_ppp_mutex.
3426 */
3427 static struct ppp *
ppp_find_unit(struct ppp_net * pn,int unit)3428 ppp_find_unit(struct ppp_net *pn, int unit)
3429 {
3430 return unit_find(&pn->units_idr, unit);
3431 }
3432
3433 /*
3434 * Locate an existing ppp channel.
3435 * The caller should have locked the all_channels_lock.
3436 * First we look in the new_channels list, then in the
3437 * all_channels list. If found in the new_channels list,
3438 * we move it to the all_channels list. This is for speed
3439 * when we have a lot of channels in use.
3440 */
3441 static struct channel *
ppp_find_channel(struct ppp_net * pn,int unit)3442 ppp_find_channel(struct ppp_net *pn, int unit)
3443 {
3444 struct channel *pch;
3445
3446 list_for_each_entry(pch, &pn->new_channels, list) {
3447 if (pch->file.index == unit) {
3448 list_move(&pch->list, &pn->all_channels);
3449 return pch;
3450 }
3451 }
3452
3453 list_for_each_entry(pch, &pn->all_channels, list) {
3454 if (pch->file.index == unit)
3455 return pch;
3456 }
3457
3458 return NULL;
3459 }
3460
3461 /*
3462 * Connect a PPP channel to a PPP interface unit.
3463 */
3464 static int
ppp_connect_channel(struct channel * pch,int unit)3465 ppp_connect_channel(struct channel *pch, int unit)
3466 {
3467 struct ppp *ppp;
3468 struct ppp_net *pn;
3469 int ret = -ENXIO;
3470 int hdrlen;
3471
3472 pn = ppp_pernet(pch->chan_net);
3473
3474 mutex_lock(&pn->all_ppp_mutex);
3475 ppp = ppp_find_unit(pn, unit);
3476 if (!ppp)
3477 goto out;
3478 write_lock_bh(&pch->upl);
3479 ret = -EINVAL;
3480 if (pch->ppp ||
3481 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3482 goto outl;
3483
3484 ppp_lock(ppp);
3485 spin_lock_bh(&pch->downl);
3486 if (!pch->chan) {
3487 /* Don't connect unregistered channels */
3488 spin_unlock_bh(&pch->downl);
3489 ppp_unlock(ppp);
3490 ret = -ENOTCONN;
3491 goto outl;
3492 }
3493 spin_unlock_bh(&pch->downl);
3494 if (pch->file.hdrlen > ppp->file.hdrlen)
3495 ppp->file.hdrlen = pch->file.hdrlen;
3496 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
3497 if (hdrlen > ppp->dev->hard_header_len)
3498 ppp->dev->hard_header_len = hdrlen;
3499 list_add_tail(&pch->clist, &ppp->channels);
3500 ++ppp->n_channels;
3501 pch->ppp = ppp;
3502 refcount_inc(&ppp->file.refcnt);
3503 ppp_unlock(ppp);
3504 ret = 0;
3505
3506 outl:
3507 write_unlock_bh(&pch->upl);
3508 out:
3509 mutex_unlock(&pn->all_ppp_mutex);
3510 return ret;
3511 }
3512
3513 /*
3514 * Disconnect a channel from its ppp unit.
3515 */
3516 static int
ppp_disconnect_channel(struct channel * pch)3517 ppp_disconnect_channel(struct channel *pch)
3518 {
3519 struct ppp *ppp;
3520 int err = -EINVAL;
3521
3522 write_lock_bh(&pch->upl);
3523 ppp = pch->ppp;
3524 pch->ppp = NULL;
3525 write_unlock_bh(&pch->upl);
3526 if (ppp) {
3527 /* remove it from the ppp unit's list */
3528 ppp_lock(ppp);
3529 list_del(&pch->clist);
3530 if (--ppp->n_channels == 0)
3531 wake_up_interruptible(&ppp->file.rwait);
3532 ppp_unlock(ppp);
3533 if (refcount_dec_and_test(&ppp->file.refcnt))
3534 ppp_destroy_interface(ppp);
3535 err = 0;
3536 }
3537 return err;
3538 }
3539
3540 /*
3541 * Free up the resources used by a ppp channel.
3542 */
ppp_destroy_channel(struct channel * pch)3543 static void ppp_destroy_channel(struct channel *pch)
3544 {
3545 put_net_track(pch->chan_net, &pch->ns_tracker);
3546 pch->chan_net = NULL;
3547
3548 atomic_dec(&channel_count);
3549
3550 if (!pch->file.dead) {
3551 /* "can't happen" */
3552 pr_err("ppp: destroying undead channel %p !\n", pch);
3553 return;
3554 }
3555 skb_queue_purge(&pch->file.xq);
3556 skb_queue_purge(&pch->file.rq);
3557 kfree(pch);
3558 }
3559
ppp_cleanup(void)3560 static void __exit ppp_cleanup(void)
3561 {
3562 /* should never happen */
3563 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3564 pr_err("PPP: removing module but units remain!\n");
3565 rtnl_link_unregister(&ppp_link_ops);
3566 unregister_chrdev(PPP_MAJOR, "ppp");
3567 device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
3568 class_destroy(ppp_class);
3569 unregister_pernet_device(&ppp_net_ops);
3570 }
3571
3572 /*
3573 * Units handling. Caller must protect concurrent access
3574 * by holding all_ppp_mutex
3575 */
3576
3577 /* associate pointer with specified number */
unit_set(struct idr * p,void * ptr,int n)3578 static int unit_set(struct idr *p, void *ptr, int n)
3579 {
3580 int unit;
3581
3582 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3583 if (unit == -ENOSPC)
3584 unit = -EINVAL;
3585 return unit;
3586 }
3587
3588 /* get new free unit number and associate pointer with it */
unit_get(struct idr * p,void * ptr,int min)3589 static int unit_get(struct idr *p, void *ptr, int min)
3590 {
3591 return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3592 }
3593
3594 /* put unit number back to a pool */
unit_put(struct idr * p,int n)3595 static void unit_put(struct idr *p, int n)
3596 {
3597 idr_remove(p, n);
3598 }
3599
3600 /* get pointer associated with the number */
unit_find(struct idr * p,int n)3601 static void *unit_find(struct idr *p, int n)
3602 {
3603 return idr_find(p, n);
3604 }
3605
3606 /* Module/initialization stuff */
3607
3608 module_init(ppp_init);
3609 module_exit(ppp_cleanup);
3610
3611 EXPORT_SYMBOL(ppp_register_net_channel);
3612 EXPORT_SYMBOL(ppp_register_channel);
3613 EXPORT_SYMBOL(ppp_unregister_channel);
3614 EXPORT_SYMBOL(ppp_channel_index);
3615 EXPORT_SYMBOL(ppp_unit_number);
3616 EXPORT_SYMBOL(ppp_dev_name);
3617 EXPORT_SYMBOL(ppp_input);
3618 EXPORT_SYMBOL(ppp_input_error);
3619 EXPORT_SYMBOL(ppp_output_wakeup);
3620 EXPORT_SYMBOL(ppp_register_compressor);
3621 EXPORT_SYMBOL(ppp_unregister_compressor);
3622 MODULE_LICENSE("GPL");
3623 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3624 MODULE_ALIAS_RTNL_LINK("ppp");
3625 MODULE_ALIAS("devname:ppp");
3626