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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/rculist.h>
37#include <linux/rtnetlink.h>
38#include <linux/if_arp.h>
39#include <linux/ip.h>
40#include <linux/tcp.h>
41#include <linux/spinlock.h>
42#include <linux/stddef.h>
43#include <linux/device.h>
44#include <linux/mutex.h>
45#include <linux/slab.h>
46#include <linux/file.h>
47#include <linux/unaligned.h>
48#include <net/netdev_lock.h>
49#include <net/slhc_vj.h>
50#include <linux/atomic.h>
51#include <linux/refcount.h>
52
53#include <linux/nsproxy.h>
54#include <net/net_namespace.h>
55#include <net/netns/generic.h>
56
57#define PPP_VERSION "2.4.2"
58
59/*
60 * Network protocols we support.
61 */
62#define NP_IP 0 /* Internet Protocol V4 */
63#define NP_IPV6 1 /* Internet Protocol V6 */
64#define NP_IPX 2 /* IPX protocol */
65#define NP_AT 3 /* Appletalk protocol */
66#define NP_MPLS_UC 4 /* MPLS unicast */
67#define NP_MPLS_MC 5 /* MPLS multicast */
68#define NUM_NP 6 /* Number of NPs. */
69
70#define MPHDRLEN 6 /* multilink protocol header length */
71#define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
72
73#define PPP_PROTO_LEN 2
74#define PPP_LCP_HDRLEN 4
75
76/* The filter instructions generated by libpcap are constructed
77 * assuming a four-byte PPP header on each packet, where the last
78 * 2 bytes are the protocol field defined in the RFC and the first
79 * byte of the first 2 bytes indicates the direction.
80 * The second byte is currently unused, but we still need to initialize
81 * it to prevent crafted BPF programs from reading them which would
82 * cause reading of uninitialized data.
83 */
84#define PPP_FILTER_OUTBOUND_TAG 0x0100
85#define PPP_FILTER_INBOUND_TAG 0x0000
86
87/*
88 * An instance of /dev/ppp can be associated with either a ppp
89 * interface unit or a ppp channel. In both cases, file->private_data
90 * points to one of these.
91 */
92struct ppp_file {
93 enum {
94 INTERFACE=1, CHANNEL
95 } kind;
96 struct sk_buff_head xq; /* pppd transmit queue */
97 struct sk_buff_head rq; /* receive queue for pppd */
98 wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
99 refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
100 int hdrlen; /* space to leave for headers */
101 int index; /* interface unit / channel number */
102 int dead; /* unit/channel has been shut down */
103};
104
105#define PF_TO_X(pf, X) container_of(pf, X, file)
106
107#define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
108#define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
109
110struct ppp_xmit_recursion {
111 struct task_struct *owner;
112 local_lock_t bh_lock;
113};
114
115/*
116 * Data structure describing one ppp unit.
117 * A ppp unit corresponds to a ppp network interface device
118 * and represents a multilink bundle.
119 * It can have 0 or more ppp channels connected to it.
120 */
121struct ppp {
122 struct ppp_file file; /* stuff for read/write/poll 0 */
123 struct file *owner; /* file that owns this unit 48 */
124 struct list_head channels; /* list of attached channels 4c */
125 int n_channels; /* how many channels are attached 54 */
126 spinlock_t rlock; /* lock for receive side 58 */
127 spinlock_t wlock; /* lock for transmit side 5c */
128 struct ppp_xmit_recursion __percpu *xmit_recursion; /* xmit recursion detect */
129 int mru; /* max receive unit 60 */
130 unsigned int flags; /* control bits 64 */
131 unsigned int xstate; /* transmit state bits 68 */
132 unsigned int rstate; /* receive state bits 6c */
133 int debug; /* debug flags 70 */
134 struct slcompress *vj; /* state for VJ header compression */
135 enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
136 struct compressor *xcomp; /* transmit packet compressor 8c */
137 void *xc_state; /* its internal state 90 */
138 struct compressor *rcomp; /* receive decompressor 94 */
139 void *rc_state; /* its internal state 98 */
140 unsigned long last_xmit; /* jiffies when last pkt sent 9c */
141 unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
142 int closing; /* is device closing down? a8 */
143#ifdef CONFIG_PPP_MULTILINK
144 int nxchan; /* next channel to send something on */
145 u32 nxseq; /* next sequence number to send */
146 int mrru; /* MP: max reconst. receive unit */
147 u32 nextseq; /* MP: seq no of next packet */
148 u32 minseq; /* MP: min of most recent seqnos */
149 struct sk_buff_head mrq; /* MP: receive reconstruction queue */
150#endif /* CONFIG_PPP_MULTILINK */
151#ifdef CONFIG_PPP_FILTER
152 struct bpf_prog *pass_filter; /* filter for packets to pass */
153 struct bpf_prog *active_filter; /* filter for pkts to reset idle */
154#endif /* CONFIG_PPP_FILTER */
155 struct net *ppp_net; /* the net we belong to */
156};
157
158/*
159 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
160 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
161 * SC_MUST_COMP
162 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
163 * Bits in xstate: SC_COMP_RUN
164 */
165#define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
166 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
167 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
168
169/*
170 * Private data structure for each channel.
171 * This includes the data structure used for multilink.
172 */
173struct channel {
174 struct ppp_file file; /* stuff for read/write/poll */
175 struct list_head list; /* link in all/new_channels list */
176 struct ppp_channel *chan; /* public channel data structure */
177 struct mutex chan_sem; /* protects `chan' during chan ioctl */
178 spinlock_t downl; /* protects `chan', file.xq dequeue */
179 struct ppp __rcu *ppp; /* ppp unit we're connected to */
180 struct net *chan_net; /* the net channel belongs to */
181 netns_tracker ns_tracker;
182 struct list_head clist; /* link in list of channels per unit */
183 spinlock_t upl; /* protects `ppp' and 'bridge' */
184 struct channel __rcu *bridge; /* "bridged" ppp channel */
185 struct rcu_head rcu; /* for RCU-deferred free of the channel */
186#ifdef CONFIG_PPP_MULTILINK
187 u8 avail; /* flag used in multilink stuff */
188 u8 had_frag; /* >= 1 fragments have been sent */
189 u32 lastseq; /* MP: last sequence # received */
190 int speed; /* speed of the corresponding ppp channel*/
191#endif /* CONFIG_PPP_MULTILINK */
192};
193
194struct ppp_config {
195 struct file *file;
196 s32 unit;
197 bool ifname_is_set;
198};
199
200/*
201 * SMP locking issues:
202 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
203 * list and the ppp.n_channels field, you need to take both locks
204 * before you modify them.
205 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
206 * channel.downl.
207 */
208
209static DEFINE_MUTEX(ppp_mutex);
210static atomic_t ppp_unit_count = ATOMIC_INIT(0);
211static atomic_t channel_count = ATOMIC_INIT(0);
212
213/* per-net private data for this module */
214static unsigned int ppp_net_id __read_mostly;
215struct ppp_net {
216 /* units to ppp mapping */
217 struct idr units_idr;
218
219 /*
220 * all_ppp_mutex protects the units_idr mapping.
221 * It also ensures that finding a ppp unit in the units_idr
222 * map and updating its file.refcnt field is atomic.
223 */
224 struct mutex all_ppp_mutex;
225
226 /* channels */
227 struct list_head all_channels;
228 struct list_head new_channels;
229 int last_channel_index;
230
231 /*
232 * all_channels_lock protects all_channels and
233 * last_channel_index, and the atomicity of find
234 * a channel and updating its file.refcnt field.
235 */
236 spinlock_t all_channels_lock;
237};
238
239/* Get the PPP protocol number from a skb */
240#define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
241
242/* We limit the length of ppp->file.rq to this (arbitrary) value */
243#define PPP_MAX_RQLEN 32
244
245/*
246 * Maximum number of multilink fragments queued up.
247 * This has to be large enough to cope with the maximum latency of
248 * the slowest channel relative to the others. Strictly it should
249 * depend on the number of channels and their characteristics.
250 */
251#define PPP_MP_MAX_QLEN 128
252
253/* Multilink header bits. */
254#define B 0x80 /* this fragment begins a packet */
255#define E 0x40 /* this fragment ends a packet */
256
257/* Compare multilink sequence numbers (assumed to be 32 bits wide) */
258#define seq_before(a, b) ((s32)((a) - (b)) < 0)
259#define seq_after(a, b) ((s32)((a) - (b)) > 0)
260
261/* Prototypes. */
262static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
263 struct file *file, unsigned int cmd, unsigned long arg);
264static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
265static int ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb);
266static int ppp_push(struct ppp *ppp, struct sk_buff *skb);
267static void ppp_channel_push(struct channel *pch);
268static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
269 struct channel *pch);
270static void ppp_receive_error(struct ppp *ppp);
271static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
272static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
273 struct sk_buff *skb);
274#ifdef CONFIG_PPP_MULTILINK
275static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
276 struct channel *pch);
277static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
278static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
279static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
280#endif /* CONFIG_PPP_MULTILINK */
281static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
282static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
283static void ppp_ccp_closed(struct ppp *ppp);
284static struct compressor *find_compressor(int type);
285static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
286static int ppp_create_interface(struct net *net, struct file *file, int *unit);
287static void init_ppp_file(struct ppp_file *pf, int kind);
288static void ppp_release_interface(struct ppp *ppp);
289static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
290static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
291static int ppp_connect_channel(struct channel *pch, int unit);
292static int ppp_disconnect_channel(struct channel *pch);
293static void ppp_release_channel(struct channel *pch);
294static int unit_get(struct idr *p, void *ptr, int min);
295static int unit_set(struct idr *p, void *ptr, int n);
296static void unit_put(struct idr *p, int n);
297static void *unit_find(struct idr *p, int n);
298static void ppp_setup(struct net_device *dev);
299
300static const struct net_device_ops ppp_netdev_ops;
301
302static const struct class ppp_class = {
303 .name = "ppp",
304};
305
306/* per net-namespace data */
307static inline struct ppp_net *ppp_pernet(struct net *net)
308{
309 return net_generic(net, ppp_net_id);
310}
311
312/* Translates a PPP protocol number to a NP index (NP == network protocol) */
313static inline int proto_to_npindex(int proto)
314{
315 switch (proto) {
316 case PPP_IP:
317 return NP_IP;
318 case PPP_IPV6:
319 return NP_IPV6;
320 case PPP_IPX:
321 return NP_IPX;
322 case PPP_AT:
323 return NP_AT;
324 case PPP_MPLS_UC:
325 return NP_MPLS_UC;
326 case PPP_MPLS_MC:
327 return NP_MPLS_MC;
328 }
329 return -EINVAL;
330}
331
332/* Translates an NP index into a PPP protocol number */
333static const int npindex_to_proto[NUM_NP] = {
334 PPP_IP,
335 PPP_IPV6,
336 PPP_IPX,
337 PPP_AT,
338 PPP_MPLS_UC,
339 PPP_MPLS_MC,
340};
341
342/* Translates an ethertype into an NP index */
343static inline int ethertype_to_npindex(int ethertype)
344{
345 switch (ethertype) {
346 case ETH_P_IP:
347 return NP_IP;
348 case ETH_P_IPV6:
349 return NP_IPV6;
350 case ETH_P_IPX:
351 return NP_IPX;
352 case ETH_P_PPPTALK:
353 case ETH_P_ATALK:
354 return NP_AT;
355 case ETH_P_MPLS_UC:
356 return NP_MPLS_UC;
357 case ETH_P_MPLS_MC:
358 return NP_MPLS_MC;
359 }
360 return -1;
361}
362
363/* Translates an NP index into an ethertype */
364static const int npindex_to_ethertype[NUM_NP] = {
365 ETH_P_IP,
366 ETH_P_IPV6,
367 ETH_P_IPX,
368 ETH_P_PPPTALK,
369 ETH_P_MPLS_UC,
370 ETH_P_MPLS_MC,
371};
372
373/*
374 * Locking shorthand.
375 */
376#define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
377#define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
378#define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
379#define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
380#define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
381 ppp_recv_lock(ppp); } while (0)
382#define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
383 ppp_xmit_unlock(ppp); } while (0)
384
385/*
386 * /dev/ppp device routines.
387 * The /dev/ppp device is used by pppd to control the ppp unit.
388 * It supports the read, write, ioctl and poll functions.
389 * Open instances of /dev/ppp can be in one of three states:
390 * unattached, attached to a ppp unit, or attached to a ppp channel.
391 */
392static int ppp_open(struct inode *inode, struct file *file)
393{
394 /*
395 * This could (should?) be enforced by the permissions on /dev/ppp.
396 */
397 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN))
398 return -EPERM;
399 return 0;
400}
401
402static int ppp_release(struct inode *unused, struct file *file)
403{
404 struct ppp_file *pf = file->private_data;
405 struct ppp *ppp;
406
407 if (pf) {
408 file->private_data = NULL;
409 switch (pf->kind) {
410 case INTERFACE:
411 ppp = PF_TO_PPP(pf);
412 rtnl_lock();
413 if (file == ppp->owner)
414 unregister_netdevice(netdev_from_priv(ppp));
415 rtnl_unlock();
416 ppp_release_interface(ppp);
417 break;
418 case CHANNEL:
419 ppp_release_channel(PF_TO_CHANNEL(pf));
420 break;
421 }
422 }
423 return 0;
424}
425
426static ssize_t ppp_read(struct file *file, char __user *buf,
427 size_t count, loff_t *ppos)
428{
429 struct ppp_file *pf = file->private_data;
430 DECLARE_WAITQUEUE(wait, current);
431 ssize_t ret;
432 struct sk_buff *skb = NULL;
433 struct iovec iov;
434 struct iov_iter to;
435
436 ret = count;
437
438 if (!pf)
439 return -ENXIO;
440 add_wait_queue(&pf->rwait, &wait);
441 for (;;) {
442 set_current_state(TASK_INTERRUPTIBLE);
443 skb = skb_dequeue(&pf->rq);
444 if (skb)
445 break;
446 ret = 0;
447 if (pf->dead)
448 break;
449 if (pf->kind == INTERFACE) {
450 /*
451 * Return 0 (EOF) on an interface that has no
452 * channels connected, unless it is looping
453 * network traffic (demand mode).
454 */
455 struct ppp *ppp = PF_TO_PPP(pf);
456
457 ppp_recv_lock(ppp);
458 if (ppp->n_channels == 0 &&
459 (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
460 ppp_recv_unlock(ppp);
461 break;
462 }
463 ppp_recv_unlock(ppp);
464 }
465 ret = -EAGAIN;
466 if (file->f_flags & O_NONBLOCK)
467 break;
468 ret = -ERESTARTSYS;
469 if (signal_pending(current))
470 break;
471 schedule();
472 }
473 set_current_state(TASK_RUNNING);
474 remove_wait_queue(&pf->rwait, &wait);
475
476 if (!skb)
477 goto out;
478
479 ret = -EOVERFLOW;
480 if (skb->len > count)
481 goto outf;
482 ret = -EFAULT;
483 iov.iov_base = buf;
484 iov.iov_len = count;
485 iov_iter_init(&to, ITER_DEST, &iov, 1, count);
486 if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
487 goto outf;
488 ret = skb->len;
489
490 outf:
491 kfree_skb(skb);
492 out:
493 return ret;
494}
495
496static bool ppp_check_packet(struct sk_buff *skb, size_t count)
497{
498 /* LCP packets must include LCP header which 4 bytes long:
499 * 1-byte code, 1-byte identifier, and 2-byte length.
500 */
501 return get_unaligned_be16(skb->data) != PPP_LCP ||
502 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
503}
504
505static ssize_t ppp_write(struct file *file, const char __user *buf,
506 size_t count, loff_t *ppos)
507{
508 struct ppp_file *pf = file->private_data;
509 struct sk_buff *skb;
510 ssize_t ret;
511
512 if (!pf)
513 return -ENXIO;
514 /* All PPP packets should start with the 2-byte protocol */
515 if (count < PPP_PROTO_LEN)
516 return -EINVAL;
517 ret = -ENOMEM;
518 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
519 if (!skb)
520 goto out;
521 skb_reserve(skb, pf->hdrlen);
522 ret = -EFAULT;
523 if (copy_from_user(skb_put(skb, count), buf, count)) {
524 kfree_skb(skb);
525 goto out;
526 }
527 ret = -EINVAL;
528 if (unlikely(!ppp_check_packet(skb, count))) {
529 kfree_skb(skb);
530 goto out;
531 }
532
533 switch (pf->kind) {
534 case INTERFACE:
535 ppp_xmit_process(PF_TO_PPP(pf), skb);
536 break;
537 case CHANNEL:
538 skb_queue_tail(&pf->xq, skb);
539 ppp_channel_push(PF_TO_CHANNEL(pf));
540 break;
541 }
542
543 ret = count;
544
545 out:
546 return ret;
547}
548
549/* No kernel lock - fine */
550static __poll_t ppp_poll(struct file *file, poll_table *wait)
551{
552 struct ppp_file *pf = file->private_data;
553 __poll_t mask;
554
555 if (!pf)
556 return 0;
557 poll_wait(file, &pf->rwait, wait);
558 mask = EPOLLOUT | EPOLLWRNORM;
559 if (!skb_queue_empty_lockless(&pf->rq))
560 mask |= EPOLLIN | EPOLLRDNORM;
561 if (pf->dead)
562 mask |= EPOLLHUP;
563 else if (pf->kind == INTERFACE) {
564 /* see comment in ppp_read */
565 struct ppp *ppp = PF_TO_PPP(pf);
566
567 ppp_recv_lock(ppp);
568 if (ppp->n_channels == 0 &&
569 (ppp->flags & SC_LOOP_TRAFFIC) == 0)
570 mask |= EPOLLIN | EPOLLRDNORM;
571 ppp_recv_unlock(ppp);
572 }
573
574 return mask;
575}
576
577#ifdef CONFIG_PPP_FILTER
578static struct bpf_prog *get_filter(struct sock_fprog *uprog)
579{
580 struct sock_fprog_kern fprog;
581 struct bpf_prog *res = NULL;
582 int err;
583
584 if (!uprog->len)
585 return NULL;
586
587 /* uprog->len is unsigned short, so no overflow here */
588 fprog.len = uprog->len;
589 fprog.filter = memdup_array_user(uprog->filter,
590 uprog->len, sizeof(struct sock_filter));
591 if (IS_ERR(fprog.filter))
592 return ERR_CAST(fprog.filter);
593
594 err = bpf_prog_create(&res, &fprog);
595 kfree(fprog.filter);
596
597 return err ? ERR_PTR(err) : res;
598}
599
600static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
601{
602 struct sock_fprog uprog;
603
604 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
605 return ERR_PTR(-EFAULT);
606 return get_filter(&uprog);
607}
608
609#ifdef CONFIG_COMPAT
610struct sock_fprog32 {
611 unsigned short len;
612 compat_caddr_t filter;
613};
614
615#define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32)
616#define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32)
617
618static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
619{
620 struct sock_fprog32 uprog32;
621 struct sock_fprog uprog;
622
623 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
624 return ERR_PTR(-EFAULT);
625 uprog.len = uprog32.len;
626 uprog.filter = compat_ptr(uprog32.filter);
627 return get_filter(&uprog);
628}
629#endif
630#endif
631
632/* Bridge one PPP channel to another.
633 * When two channels are bridged, ppp_input on one channel is redirected to
634 * the other's ops->start_xmit handler.
635 * In order to safely bridge channels we must reject channels which are already
636 * part of a bridge instance, or which form part of an existing unit.
637 * Once successfully bridged, each channel holds a reference on the other
638 * to prevent it being freed while the bridge is extant.
639 */
640static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
641{
642 spin_lock(&pch->upl);
643 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
644 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
645 spin_unlock(&pch->upl);
646 return -EALREADY;
647 }
648 refcount_inc(&pchb->file.refcnt);
649 rcu_assign_pointer(pch->bridge, pchb);
650 spin_unlock(&pch->upl);
651
652 spin_lock(&pchb->upl);
653 if (rcu_dereference_protected(pchb->ppp, lockdep_is_held(&pchb->upl)) ||
654 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
655 spin_unlock(&pchb->upl);
656 goto err_unset;
657 }
658 refcount_inc(&pch->file.refcnt);
659 rcu_assign_pointer(pchb->bridge, pch);
660 spin_unlock(&pchb->upl);
661
662 return 0;
663
664err_unset:
665 spin_lock(&pch->upl);
666 /* Re-read pch->bridge with upl held in case it was modified concurrently */
667 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
668 RCU_INIT_POINTER(pch->bridge, NULL);
669 spin_unlock(&pch->upl);
670 synchronize_rcu();
671
672 if (pchb)
673 ppp_release_channel(pchb);
674
675 return -EALREADY;
676}
677
678static int ppp_unbridge_channels(struct channel *pch)
679{
680 struct channel *pchb, *pchbb;
681
682 spin_lock(&pch->upl);
683 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
684 if (!pchb) {
685 spin_unlock(&pch->upl);
686 return -EINVAL;
687 }
688 RCU_INIT_POINTER(pch->bridge, NULL);
689 spin_unlock(&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 spin_lock(&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 spin_unlock(&pchb->upl);
701
702 synchronize_rcu();
703
704 if (pchbb == pch)
705 ppp_release_channel(pch);
706
707 ppp_release_channel(pchb);
708
709 return 0;
710}
711
712static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
713{
714 struct ppp_file *pf;
715 struct ppp *ppp;
716 int err = -EFAULT, val, val2, i;
717 struct ppp_idle32 idle32;
718 struct ppp_idle64 idle64;
719 struct npioctl npi;
720 int unit, cflags;
721 struct slcompress *vj;
722 void __user *argp = (void __user *)arg;
723 int __user *p = argp;
724
725 mutex_lock(&ppp_mutex);
726
727 pf = file->private_data;
728 if (!pf) {
729 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
730 pf, file, cmd, arg);
731 goto out;
732 }
733
734 if (cmd == PPPIOCDETACH) {
735 /*
736 * PPPIOCDETACH is no longer supported as it was heavily broken,
737 * and is only known to have been used by pppd older than
738 * ppp-2.4.2 (released November 2003).
739 */
740 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
741 current->comm, current->pid);
742 err = -EINVAL;
743 goto out;
744 }
745
746 if (pf->kind == CHANNEL) {
747 struct channel *pch, *pchb;
748 struct ppp_channel *chan;
749 struct ppp_net *pn;
750
751 pch = PF_TO_CHANNEL(pf);
752
753 switch (cmd) {
754 case PPPIOCCONNECT:
755 if (get_user(unit, p))
756 break;
757 err = ppp_connect_channel(pch, unit);
758 break;
759
760 case PPPIOCDISCONN:
761 err = ppp_disconnect_channel(pch);
762 break;
763
764 case PPPIOCBRIDGECHAN:
765 if (get_user(unit, p))
766 break;
767 err = -ENXIO;
768 pn = ppp_pernet(current->nsproxy->net_ns);
769 spin_lock_bh(&pn->all_channels_lock);
770 pchb = ppp_find_channel(pn, unit);
771 /* Hold a reference to prevent pchb being freed while
772 * we establish the bridge.
773 */
774 if (pchb)
775 refcount_inc(&pchb->file.refcnt);
776 spin_unlock_bh(&pn->all_channels_lock);
777 if (!pchb)
778 break;
779 err = ppp_bridge_channels(pch, pchb);
780 /* Drop earlier refcount now bridge establishment is complete */
781 ppp_release_channel(pchb);
782 break;
783
784 case PPPIOCUNBRIDGECHAN:
785 err = ppp_unbridge_channels(pch);
786 break;
787
788 default:
789 mutex_lock(&pch->chan_sem);
790 chan = pch->chan;
791 err = -ENOTTY;
792 if (chan && chan->ops->ioctl)
793 err = chan->ops->ioctl(chan, cmd, arg);
794 mutex_unlock(&pch->chan_sem);
795 }
796 goto out;
797 }
798
799 if (pf->kind != INTERFACE) {
800 /* can't happen */
801 pr_err("PPP: not interface or channel??\n");
802 err = -EINVAL;
803 goto out;
804 }
805
806 ppp = PF_TO_PPP(pf);
807 switch (cmd) {
808 case PPPIOCSMRU:
809 if (get_user(val, p))
810 break;
811 ppp_recv_lock(ppp);
812 ppp->mru = val;
813 ppp_recv_unlock(ppp);
814 err = 0;
815 break;
816
817 case PPPIOCSFLAGS:
818 if (get_user(val, p))
819 break;
820 ppp_lock(ppp);
821 cflags = ppp->flags & ~val;
822#ifdef CONFIG_PPP_MULTILINK
823 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
824 ppp->nextseq = 0;
825#endif
826 ppp->flags = val & SC_FLAG_BITS;
827 ppp_unlock(ppp);
828 if (cflags & SC_CCP_OPEN)
829 ppp_ccp_closed(ppp);
830 err = 0;
831 break;
832
833 case PPPIOCGFLAGS:
834 ppp_lock(ppp);
835 val = ppp->flags | ppp->xstate | ppp->rstate;
836 ppp_unlock(ppp);
837 if (put_user(val, p))
838 break;
839 err = 0;
840 break;
841
842 case PPPIOCSCOMPRESS:
843 {
844 struct ppp_option_data data;
845 if (copy_from_user(&data, argp, sizeof(data)))
846 err = -EFAULT;
847 else
848 err = ppp_set_compress(ppp, &data);
849 break;
850 }
851 case PPPIOCGUNIT:
852 if (put_user(ppp->file.index, p))
853 break;
854 err = 0;
855 break;
856
857 case PPPIOCSDEBUG:
858 if (get_user(val, p))
859 break;
860 WRITE_ONCE(ppp->debug, val);
861 err = 0;
862 break;
863
864 case PPPIOCGDEBUG:
865 if (put_user(ppp->debug, p))
866 break;
867 err = 0;
868 break;
869
870 case PPPIOCGIDLE32:
871 idle32.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ;
872 idle32.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ;
873 if (copy_to_user(argp, &idle32, sizeof(idle32)))
874 break;
875 err = 0;
876 break;
877
878 case PPPIOCGIDLE64:
879 idle64.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ;
880 idle64.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ;
881 if (copy_to_user(argp, &idle64, sizeof(idle64)))
882 break;
883 err = 0;
884 break;
885
886 case PPPIOCSMAXCID:
887 if (get_user(val, p))
888 break;
889 val2 = 15;
890 if ((val >> 16) != 0) {
891 val2 = val >> 16;
892 val &= 0xffff;
893 }
894 vj = slhc_init(val2+1, val+1);
895 if (IS_ERR(vj)) {
896 err = PTR_ERR(vj);
897 break;
898 }
899 ppp_lock(ppp);
900 if (ppp->vj)
901 slhc_free(ppp->vj);
902 ppp->vj = vj;
903 ppp_unlock(ppp);
904 err = 0;
905 break;
906
907 case PPPIOCGNPMODE:
908 case PPPIOCSNPMODE:
909 if (copy_from_user(&npi, argp, sizeof(npi)))
910 break;
911 err = proto_to_npindex(npi.protocol);
912 if (err < 0)
913 break;
914 i = err;
915 if (cmd == PPPIOCGNPMODE) {
916 err = -EFAULT;
917 npi.mode = ppp->npmode[i];
918 if (copy_to_user(argp, &npi, sizeof(npi)))
919 break;
920 } else {
921 WRITE_ONCE(ppp->npmode[i], npi.mode);
922 /* we may be able to transmit more packets now (??) */
923 netif_wake_queue(netdev_from_priv(ppp));
924 }
925 err = 0;
926 break;
927
928#ifdef CONFIG_PPP_FILTER
929 case PPPIOCSPASS:
930 case PPPIOCSACTIVE:
931 {
932 struct bpf_prog *filter = ppp_get_filter(argp);
933 struct bpf_prog **which;
934
935 if (IS_ERR(filter)) {
936 err = PTR_ERR(filter);
937 break;
938 }
939 if (cmd == PPPIOCSPASS)
940 which = &ppp->pass_filter;
941 else
942 which = &ppp->active_filter;
943 ppp_lock(ppp);
944 if (*which)
945 bpf_prog_destroy(*which);
946 *which = filter;
947 ppp_unlock(ppp);
948 err = 0;
949 break;
950 }
951#endif /* CONFIG_PPP_FILTER */
952
953#ifdef CONFIG_PPP_MULTILINK
954 case PPPIOCSMRRU:
955 if (get_user(val, p))
956 break;
957 ppp_recv_lock(ppp);
958 ppp->mrru = val;
959 ppp_recv_unlock(ppp);
960 err = 0;
961 break;
962#endif /* CONFIG_PPP_MULTILINK */
963
964 default:
965 err = -ENOTTY;
966 }
967
968out:
969 mutex_unlock(&ppp_mutex);
970
971 return err;
972}
973
974#ifdef CONFIG_COMPAT
975struct ppp_option_data32 {
976 compat_uptr_t ptr;
977 u32 length;
978 compat_int_t transmit;
979};
980#define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)
981
982static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
983{
984 struct ppp_file *pf;
985 int err = -ENOIOCTLCMD;
986 void __user *argp = (void __user *)arg;
987
988 mutex_lock(&ppp_mutex);
989
990 pf = file->private_data;
991 if (pf && pf->kind == INTERFACE) {
992 struct ppp *ppp = PF_TO_PPP(pf);
993 switch (cmd) {
994#ifdef CONFIG_PPP_FILTER
995 case PPPIOCSPASS32:
996 case PPPIOCSACTIVE32:
997 {
998 struct bpf_prog *filter = compat_ppp_get_filter(argp);
999 struct bpf_prog **which;
1000
1001 if (IS_ERR(filter)) {
1002 err = PTR_ERR(filter);
1003 break;
1004 }
1005 if (cmd == PPPIOCSPASS32)
1006 which = &ppp->pass_filter;
1007 else
1008 which = &ppp->active_filter;
1009 ppp_lock(ppp);
1010 if (*which)
1011 bpf_prog_destroy(*which);
1012 *which = filter;
1013 ppp_unlock(ppp);
1014 err = 0;
1015 break;
1016 }
1017#endif /* CONFIG_PPP_FILTER */
1018 case PPPIOCSCOMPRESS32:
1019 {
1020 struct ppp_option_data32 data32;
1021 if (copy_from_user(&data32, argp, sizeof(data32))) {
1022 err = -EFAULT;
1023 } else {
1024 struct ppp_option_data data = {
1025 .ptr = compat_ptr(data32.ptr),
1026 .length = data32.length,
1027 .transmit = data32.transmit
1028 };
1029 err = ppp_set_compress(ppp, &data);
1030 }
1031 break;
1032 }
1033 }
1034 }
1035 mutex_unlock(&ppp_mutex);
1036
1037 /* all other commands have compatible arguments */
1038 if (err == -ENOIOCTLCMD)
1039 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1040
1041 return err;
1042}
1043#endif
1044
1045static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1046 struct file *file, unsigned int cmd, unsigned long arg)
1047{
1048 int unit, err = -EFAULT;
1049 struct ppp *ppp;
1050 struct channel *chan;
1051 struct ppp_net *pn;
1052 int __user *p = (int __user *)arg;
1053
1054 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1055 return -EPERM;
1056
1057 switch (cmd) {
1058 case PPPIOCNEWUNIT:
1059 /* Create a new ppp unit */
1060 if (get_user(unit, p))
1061 break;
1062 err = ppp_create_interface(net, file, &unit);
1063 if (err < 0)
1064 break;
1065
1066 err = -EFAULT;
1067 if (put_user(unit, p))
1068 break;
1069 err = 0;
1070 break;
1071
1072 case PPPIOCATTACH:
1073 /* Attach to an existing ppp unit */
1074 if (get_user(unit, p))
1075 break;
1076 err = -ENXIO;
1077 pn = ppp_pernet(net);
1078 mutex_lock(&pn->all_ppp_mutex);
1079 ppp = ppp_find_unit(pn, unit);
1080 if (ppp) {
1081 refcount_inc(&ppp->file.refcnt);
1082 file->private_data = &ppp->file;
1083 err = 0;
1084 }
1085 mutex_unlock(&pn->all_ppp_mutex);
1086 break;
1087
1088 case PPPIOCATTCHAN:
1089 if (get_user(unit, p))
1090 break;
1091 err = -ENXIO;
1092 pn = ppp_pernet(net);
1093 spin_lock_bh(&pn->all_channels_lock);
1094 chan = ppp_find_channel(pn, unit);
1095 if (chan) {
1096 refcount_inc(&chan->file.refcnt);
1097 file->private_data = &chan->file;
1098 err = 0;
1099 }
1100 spin_unlock_bh(&pn->all_channels_lock);
1101 break;
1102
1103 default:
1104 err = -ENOTTY;
1105 }
1106
1107 return err;
1108}
1109
1110static const struct file_operations ppp_device_fops = {
1111 .owner = THIS_MODULE,
1112 .read = ppp_read,
1113 .write = ppp_write,
1114 .poll = ppp_poll,
1115 .unlocked_ioctl = ppp_ioctl,
1116#ifdef CONFIG_COMPAT
1117 .compat_ioctl = ppp_compat_ioctl,
1118#endif
1119 .open = ppp_open,
1120 .release = ppp_release,
1121 .llseek = noop_llseek,
1122};
1123
1124static void ppp_nl_dellink(struct net_device *dev, struct list_head *head);
1125
1126static __net_init int ppp_init_net(struct net *net)
1127{
1128 struct ppp_net *pn = net_generic(net, ppp_net_id);
1129
1130 idr_init(&pn->units_idr);
1131 mutex_init(&pn->all_ppp_mutex);
1132
1133 INIT_LIST_HEAD(&pn->all_channels);
1134 INIT_LIST_HEAD(&pn->new_channels);
1135
1136 spin_lock_init(&pn->all_channels_lock);
1137
1138 return 0;
1139}
1140
1141static __net_exit void ppp_exit_rtnl_net(struct net *net,
1142 struct list_head *dev_to_kill)
1143{
1144 struct ppp_net *pn = net_generic(net, ppp_net_id);
1145 struct ppp *ppp;
1146 int id;
1147
1148 idr_for_each_entry(&pn->units_idr, ppp, id)
1149 ppp_nl_dellink(netdev_from_priv(ppp), dev_to_kill);
1150}
1151
1152static __net_exit void ppp_exit_net(struct net *net)
1153{
1154 struct ppp_net *pn = net_generic(net, ppp_net_id);
1155
1156 mutex_destroy(&pn->all_ppp_mutex);
1157 idr_destroy(&pn->units_idr);
1158 WARN_ON_ONCE(!list_empty(&pn->all_channels));
1159 WARN_ON_ONCE(!list_empty(&pn->new_channels));
1160}
1161
1162static struct pernet_operations ppp_net_ops = {
1163 .init = ppp_init_net,
1164 .exit_rtnl = ppp_exit_rtnl_net,
1165 .exit = ppp_exit_net,
1166 .id = &ppp_net_id,
1167 .size = sizeof(struct ppp_net),
1168};
1169
1170static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1171{
1172 struct net_device *dev = netdev_from_priv(ppp);
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(dev->name, IFNAMSIZ, "ppp%i", ret);
1185 if (!netdev_name_in_use(ppp->ppp_net, 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(dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
1214
1215 mutex_unlock(&pn->all_ppp_mutex);
1216
1217 ret = register_netdevice(dev);
1218 if (ret < 0)
1219 goto err_unit;
1220
1221 atomic_inc(&ppp_unit_count);
1222
1223 return 0;
1224
1225err_unit:
1226 mutex_lock(&pn->all_ppp_mutex);
1227 unit_put(&pn->units_idr, ppp->file.index);
1228err:
1229 mutex_unlock(&pn->all_ppp_mutex);
1230
1231 return ret;
1232}
1233
1234static 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->ppp_net = src_net;
1243 ppp->mru = PPP_MRU;
1244 ppp->owner = conf->file;
1245
1246 init_ppp_file(&ppp->file, INTERFACE);
1247 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1248
1249 for (indx = 0; indx < NUM_NP; ++indx)
1250 ppp->npmode[indx] = NPMODE_PASS;
1251 INIT_LIST_HEAD(&ppp->channels);
1252 spin_lock_init(&ppp->rlock);
1253 spin_lock_init(&ppp->wlock);
1254
1255 ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion);
1256 if (!ppp->xmit_recursion) {
1257 err = -ENOMEM;
1258 goto err1;
1259 }
1260 for_each_possible_cpu(cpu) {
1261 struct ppp_xmit_recursion *xmit_recursion;
1262
1263 xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu);
1264 xmit_recursion->owner = NULL;
1265 local_lock_init(&xmit_recursion->bh_lock);
1266 }
1267
1268#ifdef CONFIG_PPP_MULTILINK
1269 ppp->minseq = -1;
1270 skb_queue_head_init(&ppp->mrq);
1271#endif /* CONFIG_PPP_MULTILINK */
1272#ifdef CONFIG_PPP_FILTER
1273 ppp->pass_filter = NULL;
1274 ppp->active_filter = NULL;
1275#endif /* CONFIG_PPP_FILTER */
1276
1277 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set);
1278 if (err < 0)
1279 goto err2;
1280
1281 conf->file->private_data = &ppp->file;
1282
1283 return 0;
1284err2:
1285 free_percpu(ppp->xmit_recursion);
1286err1:
1287 return err;
1288}
1289
1290static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1291 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
1292};
1293
1294static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1295 struct netlink_ext_ack *extack)
1296{
1297 if (!data)
1298 return -EINVAL;
1299
1300 if (!data[IFLA_PPP_DEV_FD])
1301 return -EINVAL;
1302 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0)
1303 return -EBADF;
1304
1305 return 0;
1306}
1307
1308static int ppp_nl_newlink(struct net_device *dev,
1309 struct rtnl_newlink_params *params,
1310 struct netlink_ext_ack *extack)
1311{
1312 struct net *link_net = rtnl_newlink_link_net(params);
1313 struct nlattr **data = params->data;
1314 struct nlattr **tb = params->tb;
1315 struct ppp_config conf = {
1316 .unit = -1,
1317 .ifname_is_set = true,
1318 };
1319 struct file *file;
1320 int err;
1321
1322 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD]));
1323 if (!file)
1324 return -EBADF;
1325
1326 /* rtnl_lock is already held here, but ppp_create_interface() locks
1327 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1328 * possible deadlock due to lock order inversion, at the cost of
1329 * pushing the problem back to userspace.
1330 */
1331 if (!mutex_trylock(&ppp_mutex)) {
1332 err = -EBUSY;
1333 goto out;
1334 }
1335
1336 if (file->f_op != &ppp_device_fops || file->private_data) {
1337 err = -EBADF;
1338 goto out_unlock;
1339 }
1340
1341 conf.file = file;
1342
1343 /* Don't use device name generated by the rtnetlink layer when ifname
1344 * isn't specified. Let ppp_dev_configure() set the device name using
1345 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1346 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1347 */
1348 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
1349 conf.ifname_is_set = false;
1350
1351 err = ppp_dev_configure(link_net, dev, &conf);
1352
1353out_unlock:
1354 mutex_unlock(&ppp_mutex);
1355out:
1356 fput(file);
1357
1358 return err;
1359}
1360
1361static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1362{
1363 unregister_netdevice_queue(dev, head);
1364}
1365
1366static size_t ppp_nl_get_size(const struct net_device *dev)
1367{
1368 return 0;
1369}
1370
1371static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1372{
1373 return 0;
1374}
1375
1376static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1377{
1378 struct ppp *ppp = netdev_priv(dev);
1379
1380 return READ_ONCE(ppp->ppp_net);
1381}
1382
1383static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1384 .kind = "ppp",
1385 .maxtype = IFLA_PPP_MAX,
1386 .policy = ppp_nl_policy,
1387 .priv_size = sizeof(struct ppp),
1388 .setup = ppp_setup,
1389 .validate = ppp_nl_validate,
1390 .newlink = ppp_nl_newlink,
1391 .dellink = ppp_nl_dellink,
1392 .get_size = ppp_nl_get_size,
1393 .fill_info = ppp_nl_fill_info,
1394 .get_link_net = ppp_nl_get_link_net,
1395};
1396
1397#define PPP_MAJOR 108
1398
1399/* Called at boot time if ppp is compiled into the kernel,
1400 or at module load time (from init_module) if compiled as a module. */
1401static int __init ppp_init(void)
1402{
1403 int err;
1404
1405 pr_info("PPP generic driver version " PPP_VERSION "\n");
1406
1407 err = register_pernet_device(&ppp_net_ops);
1408 if (err) {
1409 pr_err("failed to register PPP pernet device (%d)\n", err);
1410 goto out;
1411 }
1412
1413 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
1414 if (err) {
1415 pr_err("failed to register PPP device (%d)\n", err);
1416 goto out_net;
1417 }
1418
1419 err = class_register(&ppp_class);
1420 if (err)
1421 goto out_chrdev;
1422
1423 err = rtnl_link_register(&ppp_link_ops);
1424 if (err) {
1425 pr_err("failed to register rtnetlink PPP handler\n");
1426 goto out_class;
1427 }
1428
1429 /* not a big deal if we fail here :-) */
1430 device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
1431
1432 return 0;
1433
1434out_class:
1435 class_unregister(&ppp_class);
1436out_chrdev:
1437 unregister_chrdev(PPP_MAJOR, "ppp");
1438out_net:
1439 unregister_pernet_device(&ppp_net_ops);
1440out:
1441 return err;
1442}
1443
1444/*
1445 * Network interface unit routines.
1446 */
1447static netdev_tx_t
1448ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1449{
1450 struct ppp *ppp = netdev_priv(dev);
1451 int npi, proto;
1452 unsigned char *pp;
1453
1454 npi = ethertype_to_npindex(ntohs(skb->protocol));
1455 if (npi < 0)
1456 goto outf;
1457
1458 /* Drop, accept or reject the packet */
1459 switch (READ_ONCE(ppp->npmode[npi])) {
1460 case NPMODE_PASS:
1461 break;
1462 case NPMODE_QUEUE:
1463 /* it would be nice to have a way to tell the network
1464 system to queue this one up for later. */
1465 goto outf;
1466 case NPMODE_DROP:
1467 case NPMODE_ERROR:
1468 goto outf;
1469 }
1470
1471 /* Put the 2-byte PPP protocol number on the front,
1472 making sure there is room for the address and control fields. */
1473 if (skb_cow_head(skb, PPP_HDRLEN))
1474 goto outf;
1475
1476 pp = skb_push(skb, 2);
1477 proto = npindex_to_proto[npi];
1478 put_unaligned_be16(proto, pp);
1479
1480 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
1481 ppp_xmit_process(ppp, skb);
1482
1483 return NETDEV_TX_OK;
1484
1485 outf:
1486 kfree_skb(skb);
1487 DEV_STATS_INC(dev, tx_dropped);
1488 return NETDEV_TX_OK;
1489}
1490
1491static int
1492ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1493 void __user *addr, int cmd)
1494{
1495 struct ppp *ppp = netdev_priv(dev);
1496 int err = -EFAULT;
1497 struct ppp_stats stats;
1498 struct ppp_comp_stats cstats;
1499 char *vers;
1500
1501 switch (cmd) {
1502 case SIOCGPPPSTATS:
1503 ppp_get_stats(ppp, &stats);
1504 if (copy_to_user(addr, &stats, sizeof(stats)))
1505 break;
1506 err = 0;
1507 break;
1508
1509 case SIOCGPPPCSTATS:
1510 memset(&cstats, 0, sizeof(cstats));
1511 if (ppp->xc_state)
1512 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1513 if (ppp->rc_state)
1514 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1515 if (copy_to_user(addr, &cstats, sizeof(cstats)))
1516 break;
1517 err = 0;
1518 break;
1519
1520 case SIOCGPPPVER:
1521 vers = PPP_VERSION;
1522 if (copy_to_user(addr, vers, strlen(vers) + 1))
1523 break;
1524 err = 0;
1525 break;
1526
1527 default:
1528 err = -EINVAL;
1529 }
1530
1531 return err;
1532}
1533
1534static void
1535ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1536{
1537 stats64->rx_errors = DEV_STATS_READ(dev, rx_errors);
1538 stats64->tx_errors = DEV_STATS_READ(dev, tx_errors);
1539 stats64->rx_dropped = DEV_STATS_READ(dev, rx_dropped);
1540 stats64->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
1541 stats64->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors);
1542 dev_fetch_sw_netstats(stats64, dev->tstats);
1543}
1544
1545static int ppp_dev_init(struct net_device *dev)
1546{
1547 struct ppp *ppp;
1548
1549 netdev_lockdep_set_classes(dev);
1550
1551 ppp = netdev_priv(dev);
1552 /* Let the netdevice take a reference on the ppp file. This ensures
1553 * that ppp_destroy_interface() won't run before the device gets
1554 * unregistered.
1555 */
1556 refcount_inc(&ppp->file.refcnt);
1557
1558 return 0;
1559}
1560
1561static void ppp_dev_uninit(struct net_device *dev)
1562{
1563 struct ppp *ppp = netdev_priv(dev);
1564 struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
1565
1566 ppp_lock(ppp);
1567 ppp->closing = 1;
1568 ppp_unlock(ppp);
1569
1570 mutex_lock(&pn->all_ppp_mutex);
1571 unit_put(&pn->units_idr, ppp->file.index);
1572 mutex_unlock(&pn->all_ppp_mutex);
1573
1574 ppp->owner = NULL;
1575
1576 ppp->file.dead = 1;
1577 wake_up_interruptible(&ppp->file.rwait);
1578}
1579
1580static void ppp_dev_priv_destructor(struct net_device *dev)
1581{
1582 struct ppp *ppp;
1583
1584 ppp = netdev_priv(dev);
1585 ppp_release_interface(ppp);
1586}
1587
1588static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1589 struct net_device_path *path)
1590{
1591 struct ppp *ppp = netdev_priv(ctx->dev);
1592 struct ppp_channel *chan;
1593 struct channel *pch;
1594
1595 if (ppp->flags & SC_MULTILINK)
1596 return -EOPNOTSUPP;
1597
1598 pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist);
1599 if (!pch)
1600 return -ENODEV;
1601
1602 chan = pch->chan;
1603 if (!chan->ops->fill_forward_path)
1604 return -EOPNOTSUPP;
1605
1606 return chan->ops->fill_forward_path(ctx, path, chan);
1607}
1608
1609static const struct net_device_ops ppp_netdev_ops = {
1610 .ndo_init = ppp_dev_init,
1611 .ndo_uninit = ppp_dev_uninit,
1612 .ndo_start_xmit = ppp_start_xmit,
1613 .ndo_siocdevprivate = ppp_net_siocdevprivate,
1614 .ndo_get_stats64 = ppp_get_stats64,
1615 .ndo_fill_forward_path = ppp_fill_forward_path,
1616};
1617
1618static const struct device_type ppp_type = {
1619 .name = "ppp",
1620};
1621
1622static void ppp_setup(struct net_device *dev)
1623{
1624 dev->netdev_ops = &ppp_netdev_ops;
1625 SET_NETDEV_DEVTYPE(dev, &ppp_type);
1626
1627 dev->lltx = true;
1628
1629 dev->hard_header_len = PPP_HDRLEN;
1630 dev->mtu = PPP_MRU;
1631 dev->addr_len = 0;
1632 dev->tx_queue_len = 3;
1633 dev->type = ARPHRD_PPP;
1634 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1635 dev->priv_destructor = ppp_dev_priv_destructor;
1636 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1637 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST;
1638 dev->hw_features = dev->features;
1639 netif_keep_dst(dev);
1640}
1641
1642/*
1643 * Transmit-side routines.
1644 */
1645
1646/* Called to do any work queued up on the transmit side that can now be done */
1647static void ppp_xmit_flush(struct ppp *ppp)
1648{
1649 struct sk_buff *skb;
1650
1651 while ((skb = skb_dequeue(&ppp->file.xq))) {
1652 if (unlikely(!ppp_push(ppp, skb))) {
1653 skb_queue_head(&ppp->file.xq, skb);
1654 return;
1655 }
1656 }
1657 /* If there's no work left to do, tell the core net code that we can
1658 * accept some more.
1659 */
1660 netif_wake_queue(netdev_from_priv(ppp));
1661}
1662
1663static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1664{
1665 ppp_xmit_lock(ppp);
1666 if (unlikely(ppp->closing)) {
1667 kfree_skb(skb);
1668 goto out;
1669 }
1670 if (unlikely(ppp_prepare_tx_skb(ppp, &skb)))
1671 goto out;
1672 /* Fastpath: No backlog, just send the new skb. */
1673 if (likely(skb_queue_empty(&ppp->file.xq))) {
1674 if (unlikely(!ppp_push(ppp, skb))) {
1675 skb_queue_tail(&ppp->file.xq, skb);
1676 netif_stop_queue(netdev_from_priv(ppp));
1677 }
1678 goto out;
1679 }
1680
1681 /* Slowpath: Enqueue the new skb and process backlog */
1682 skb_queue_tail(&ppp->file.xq, skb);
1683 ppp_xmit_flush(ppp);
1684out:
1685 ppp_xmit_unlock(ppp);
1686}
1687
1688static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1689{
1690 struct ppp_xmit_recursion *xmit_recursion;
1691
1692 local_bh_disable();
1693
1694 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
1695 if (xmit_recursion->owner == current)
1696 goto err;
1697 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
1698 xmit_recursion->owner = current;
1699
1700 __ppp_xmit_process(ppp, skb);
1701
1702 xmit_recursion->owner = NULL;
1703 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
1704 local_bh_enable();
1705
1706 return;
1707
1708err:
1709 local_bh_enable();
1710
1711 kfree_skb(skb);
1712
1713 if (net_ratelimit())
1714 netdev_err(netdev_from_priv(ppp), "recursion detected\n");
1715}
1716
1717static inline struct sk_buff *
1718pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1719{
1720 struct net_device *dev = netdev_from_priv(ppp);
1721 struct sk_buff *new_skb;
1722 int len;
1723 int new_skb_size = dev->mtu +
1724 ppp->xcomp->comp_extra + dev->hard_header_len;
1725 int compressor_skb_size = dev->mtu +
1726 ppp->xcomp->comp_extra + PPP_HDRLEN;
1727
1728 if (skb_linearize(skb))
1729 return NULL;
1730
1731 new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1732 if (!new_skb) {
1733 if (net_ratelimit())
1734 netdev_err(dev, "PPP: no memory (comp pkt)\n");
1735 return NULL;
1736 }
1737 if (dev->hard_header_len > PPP_HDRLEN)
1738 skb_reserve(new_skb, dev->hard_header_len - PPP_HDRLEN);
1739
1740 /* compressor still expects A/C bytes in hdr */
1741 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1742 new_skb->data, skb->len + 2,
1743 compressor_skb_size);
1744 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1745 consume_skb(skb);
1746 skb = new_skb;
1747 skb_put(skb, len);
1748 skb_pull(skb, 2); /* pull off A/C bytes */
1749 } else if (len == 0) {
1750 /* didn't compress, or CCP not up yet */
1751 consume_skb(new_skb);
1752 new_skb = skb;
1753 } else {
1754 /*
1755 * (len < 0)
1756 * MPPE requires that we do not send unencrypted
1757 * frames. The compressor will return -1 if we
1758 * should drop the frame. We cannot simply test
1759 * the compress_proto because MPPE and MPPC share
1760 * the same number.
1761 */
1762 if (net_ratelimit())
1763 netdev_err(dev, "ppp: compressor dropped pkt\n");
1764 consume_skb(new_skb);
1765 new_skb = NULL;
1766 }
1767 return new_skb;
1768}
1769
1770/*
1771 * Compress and prepare to send a frame.
1772 * The caller should have locked the xmit path.
1773 * Returns 1 if the skb was consumed, 0 if it can be passed to ppp_push().
1774 * @pskb is updated if a compressor is in use.
1775 */
1776static int
1777ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb)
1778{
1779 struct net_device *dev = netdev_from_priv(ppp);
1780 struct sk_buff *skb = *pskb;
1781 int proto = PPP_PROTO(skb);
1782 struct sk_buff *new_skb;
1783 int len;
1784 unsigned char *cp;
1785
1786 skb->dev = dev;
1787
1788 if (proto < 0x8000) {
1789#ifdef CONFIG_PPP_FILTER
1790 /* check if the packet passes the pass and active filters.
1791 * See comment for PPP_FILTER_OUTBOUND_TAG above.
1792 */
1793 *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_OUTBOUND_TAG);
1794 if (ppp->pass_filter &&
1795 bpf_prog_run(ppp->pass_filter, skb) == 0) {
1796 if (READ_ONCE(ppp->debug) & 1)
1797 netdev_printk(KERN_DEBUG, dev,
1798 "PPP: outbound frame "
1799 "not passed\n");
1800 kfree_skb(skb);
1801 return 1;
1802 }
1803 /* if this packet passes the active filter, record the time */
1804 if (!(ppp->active_filter &&
1805 bpf_prog_run(ppp->active_filter, skb) == 0))
1806 WRITE_ONCE(ppp->last_xmit, jiffies);
1807 skb_pull(skb, 2);
1808#else
1809 /* for data packets, record the time */
1810 WRITE_ONCE(ppp->last_xmit, jiffies);
1811#endif /* CONFIG_PPP_FILTER */
1812 }
1813
1814 dev_sw_netstats_tx_add(dev, 1, skb->len - PPP_PROTO_LEN);
1815
1816 switch (proto) {
1817 case PPP_IP:
1818 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1819 break;
1820
1821 if (skb_linearize(skb))
1822 goto drop;
1823
1824 /* try to do VJ TCP header compression */
1825 new_skb = alloc_skb(skb->len + dev->hard_header_len - 2,
1826 GFP_ATOMIC);
1827 if (!new_skb) {
1828 netdev_err(dev, "PPP: no memory (VJ comp pkt)\n");
1829 goto drop;
1830 }
1831 skb_reserve(new_skb, dev->hard_header_len - 2);
1832 cp = skb->data + 2;
1833 len = slhc_compress(ppp->vj, cp, skb->len - 2,
1834 new_skb->data + 2, &cp,
1835 !(ppp->flags & SC_NO_TCP_CCID));
1836 if (cp == skb->data + 2) {
1837 /* didn't compress */
1838 consume_skb(new_skb);
1839 } else {
1840 if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1841 proto = PPP_VJC_COMP;
1842 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1843 } else {
1844 proto = PPP_VJC_UNCOMP;
1845 cp[0] = skb->data[2];
1846 }
1847 consume_skb(skb);
1848 skb = new_skb;
1849 *pskb = skb;
1850 cp = skb_put(skb, len + 2);
1851 cp[0] = 0;
1852 cp[1] = proto;
1853 }
1854 break;
1855
1856 case PPP_CCP:
1857 /* peek at outbound CCP frames */
1858 ppp_ccp_peek(ppp, skb, 0);
1859 break;
1860 }
1861
1862 /* try to do packet compression */
1863 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1864 proto != PPP_LCP && proto != PPP_CCP) {
1865 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1866 if (net_ratelimit())
1867 netdev_err(dev,
1868 "ppp: compression required but "
1869 "down - pkt dropped.\n");
1870 goto drop;
1871 }
1872 new_skb = pad_compress_skb(ppp, skb);
1873 if (!new_skb)
1874 goto drop;
1875 skb = new_skb;
1876 *pskb = skb;
1877 }
1878
1879 /*
1880 * If we are waiting for traffic (demand dialling),
1881 * queue it up for pppd to receive.
1882 */
1883 if (ppp->flags & SC_LOOP_TRAFFIC) {
1884 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1885 goto drop;
1886 skb_queue_tail(&ppp->file.rq, skb);
1887 wake_up_interruptible(&ppp->file.rwait);
1888 return 1;
1889 }
1890
1891 return 0;
1892
1893 drop:
1894 kfree_skb(skb);
1895 DEV_STATS_INC(dev, tx_errors);
1896 return 1;
1897}
1898
1899/*
1900 * Try to send the frame.
1901 * The caller should have the xmit path locked.
1902 * Returns 1 if the skb was consumed, 0 if not.
1903 */
1904static int
1905ppp_push(struct ppp *ppp, struct sk_buff *skb)
1906{
1907 struct list_head *list;
1908 struct channel *pch;
1909
1910 list = &ppp->channels;
1911 if (list_empty(list)) {
1912 /* nowhere to send the packet, just drop it */
1913 kfree_skb(skb);
1914 return 1;
1915 }
1916
1917 if ((ppp->flags & SC_MULTILINK) == 0) {
1918 struct ppp_channel *chan;
1919 int ret;
1920 /* not doing multilink: send it down the first channel */
1921 list = list->next;
1922 pch = list_entry(list, struct channel, clist);
1923
1924 spin_lock(&pch->downl);
1925 chan = pch->chan;
1926 if (unlikely(!chan->direct_xmit && skb_linearize(skb))) {
1927 /* channel requires a linear skb but linearization
1928 * failed
1929 */
1930 kfree_skb(skb);
1931 ret = 1;
1932 goto out;
1933 }
1934
1935 ret = chan->ops->start_xmit(chan, skb);
1936
1937out:
1938 spin_unlock(&pch->downl);
1939 return ret;
1940 }
1941
1942#ifdef CONFIG_PPP_MULTILINK
1943 /* Multilink: fragment the packet over as many links
1944 as can take the packet at the moment. */
1945 if (!ppp_mp_explode(ppp, skb))
1946 return 0;
1947#endif /* CONFIG_PPP_MULTILINK */
1948
1949 kfree_skb(skb);
1950 return 1;
1951}
1952
1953#ifdef CONFIG_PPP_MULTILINK
1954static bool mp_protocol_compress __read_mostly = true;
1955module_param(mp_protocol_compress, bool, 0644);
1956MODULE_PARM_DESC(mp_protocol_compress,
1957 "compress protocol id in multilink fragments");
1958
1959/*
1960 * Divide a packet to be transmitted into fragments and
1961 * send them out the individual links.
1962 */
1963static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1964{
1965 struct net_device *dev = netdev_from_priv(ppp);
1966 int len, totlen;
1967 int i, bits, hdrlen, mtu;
1968 int flen;
1969 int navail, nfree, nzero;
1970 int nbigger;
1971 int totspeed;
1972 int totfree;
1973 unsigned char *p, *q;
1974 struct list_head *list;
1975 struct channel *pch;
1976 struct sk_buff *frag;
1977 struct ppp_channel *chan;
1978
1979 totspeed = 0; /*total bitrate of the bundle*/
1980 nfree = 0; /* # channels which have no packet already queued */
1981 navail = 0; /* total # of usable channels (not deregistered) */
1982 nzero = 0; /* number of channels with zero speed associated*/
1983 totfree = 0; /*total # of channels available and
1984 *having no queued packets before
1985 *starting the fragmentation*/
1986
1987 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1988 i = 0;
1989 list_for_each_entry(pch, &ppp->channels, clist) {
1990 pch->avail = 1;
1991 navail++;
1992 pch->speed = pch->chan->speed;
1993
1994 if (skb_queue_empty(&pch->file.xq) || !pch->had_frag) {
1995 if (pch->speed == 0)
1996 nzero++;
1997 else
1998 totspeed += pch->speed;
1999
2000 pch->avail = 2;
2001 ++nfree;
2002 ++totfree;
2003 }
2004 if (!pch->had_frag && i < ppp->nxchan)
2005 ppp->nxchan = i;
2006
2007 ++i;
2008 }
2009 /*
2010 * Don't start sending this packet unless at least half of
2011 * the channels are free. This gives much better TCP
2012 * performance if we have a lot of channels.
2013 */
2014 if (nfree == 0 || nfree < navail / 2)
2015 return 0; /* can't take now, leave it in transmit queue */
2016
2017 /* Do protocol field compression */
2018 if (skb_linearize(skb))
2019 goto err_linearize;
2020 p = skb->data;
2021 len = skb->len;
2022 if (*p == 0 && mp_protocol_compress) {
2023 ++p;
2024 --len;
2025 }
2026
2027 totlen = len;
2028 nbigger = len % nfree;
2029
2030 /* skip to the channel after the one we last used
2031 and start at that one */
2032 list = &ppp->channels;
2033 for (i = 0; i < ppp->nxchan; ++i) {
2034 list = list->next;
2035 if (list == &ppp->channels) {
2036 i = 0;
2037 break;
2038 }
2039 }
2040
2041 /* create a fragment for each channel */
2042 bits = B;
2043 while (len > 0) {
2044 list = list->next;
2045 if (list == &ppp->channels) {
2046 i = 0;
2047 continue;
2048 }
2049 pch = list_entry(list, struct channel, clist);
2050 ++i;
2051 if (!pch->avail)
2052 continue;
2053
2054 /*
2055 * Skip this channel if it has a fragment pending already and
2056 * we haven't given a fragment to all of the free channels.
2057 */
2058 if (pch->avail == 1) {
2059 if (nfree > 0)
2060 continue;
2061 } else {
2062 pch->avail = 1;
2063 }
2064
2065 spin_lock(&pch->downl);
2066 /*
2067 *if the channel speed is not set divide
2068 *the packet evenly among the free channels;
2069 *otherwise divide it according to the speed
2070 *of the channel we are going to transmit on
2071 */
2072 flen = len;
2073 if (nfree > 0) {
2074 if (pch->speed == 0) {
2075 flen = len/nfree;
2076 if (nbigger > 0) {
2077 flen++;
2078 nbigger--;
2079 }
2080 } else {
2081 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2082 ((totspeed*totfree)/pch->speed)) - hdrlen;
2083 if (nbigger > 0) {
2084 flen += ((totfree - nzero)*pch->speed)/totspeed;
2085 nbigger -= ((totfree - nzero)*pch->speed)/
2086 totspeed;
2087 }
2088 }
2089 nfree--;
2090 }
2091
2092 /*
2093 *check if we are on the last channel or
2094 *we exceded the length of the data to
2095 *fragment
2096 */
2097 if ((nfree <= 0) || (flen > len))
2098 flen = len;
2099 /*
2100 *it is not worth to tx on slow channels:
2101 *in that case from the resulting flen according to the
2102 *above formula will be equal or less than zero.
2103 *Skip the channel in this case
2104 */
2105 if (flen <= 0) {
2106 pch->avail = 2;
2107 spin_unlock(&pch->downl);
2108 continue;
2109 }
2110
2111 /*
2112 * hdrlen includes the 2-byte PPP protocol field, but the
2113 * MTU counts only the payload excluding the protocol field.
2114 * (RFC1661 Section 2)
2115 */
2116 mtu = pch->chan->mtu - (hdrlen - 2);
2117 if (mtu < 4)
2118 mtu = 4;
2119 if (flen > mtu)
2120 flen = mtu;
2121 if (flen == len)
2122 bits |= E;
2123 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
2124 if (!frag)
2125 goto noskb;
2126 q = skb_put(frag, flen + hdrlen);
2127
2128 /* make the MP header */
2129 put_unaligned_be16(PPP_MP, q);
2130 if (ppp->flags & SC_MP_XSHORTSEQ) {
2131 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2132 q[3] = ppp->nxseq;
2133 } else {
2134 q[2] = bits;
2135 q[3] = ppp->nxseq >> 16;
2136 q[4] = ppp->nxseq >> 8;
2137 q[5] = ppp->nxseq;
2138 }
2139
2140 memcpy(q + hdrlen, p, flen);
2141
2142 /* try to send it down the channel */
2143 chan = pch->chan;
2144 if (!skb_queue_empty(&pch->file.xq) ||
2145 !chan->ops->start_xmit(chan, frag))
2146 skb_queue_tail(&pch->file.xq, frag);
2147 pch->had_frag = 1;
2148 p += flen;
2149 len -= flen;
2150 ++ppp->nxseq;
2151 bits = 0;
2152 spin_unlock(&pch->downl);
2153 }
2154 ppp->nxchan = i;
2155
2156 return 1;
2157
2158 noskb:
2159 spin_unlock(&pch->downl);
2160 err_linearize:
2161 if (READ_ONCE(ppp->debug) & 1)
2162 netdev_err(dev, "PPP: no memory (fragment)\n");
2163 DEV_STATS_INC(dev, tx_errors);
2164 ++ppp->nxseq;
2165 return 1; /* abandon the frame */
2166}
2167#endif /* CONFIG_PPP_MULTILINK */
2168
2169/* Try to send data out on a channel */
2170static void __ppp_channel_push(struct channel *pch, struct ppp *ppp)
2171{
2172 struct sk_buff *skb;
2173
2174 spin_lock(&pch->downl);
2175 if (pch->chan) {
2176 while (!skb_queue_empty(&pch->file.xq)) {
2177 skb = skb_dequeue(&pch->file.xq);
2178 if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2179 /* put the packet back and try again later */
2180 skb_queue_head(&pch->file.xq, skb);
2181 break;
2182 }
2183 }
2184 } else {
2185 /* channel got deregistered */
2186 skb_queue_purge(&pch->file.xq);
2187 }
2188 spin_unlock(&pch->downl);
2189 /* see if there is anything from the attached unit to be sent */
2190 if (skb_queue_empty(&pch->file.xq)) {
2191 if (ppp) {
2192 ppp_xmit_lock(ppp);
2193 if (!ppp->closing)
2194 ppp_xmit_flush(ppp);
2195 ppp_xmit_unlock(ppp);
2196 }
2197 }
2198}
2199
2200static void ppp_channel_push(struct channel *pch)
2201{
2202 struct ppp_xmit_recursion *xmit_recursion;
2203 struct ppp *ppp;
2204
2205 rcu_read_lock_bh();
2206 ppp = rcu_dereference_bh(pch->ppp);
2207 if (ppp) {
2208 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
2209 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
2210 xmit_recursion->owner = current;
2211 __ppp_channel_push(pch, ppp);
2212 xmit_recursion->owner = NULL;
2213 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
2214 } else {
2215 __ppp_channel_push(pch, NULL);
2216 }
2217 rcu_read_unlock_bh();
2218}
2219
2220/*
2221 * Receive-side routines.
2222 */
2223
2224struct ppp_mp_skb_parm {
2225 u32 sequence;
2226 u8 BEbits;
2227};
2228#define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
2229
2230static inline void
2231ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2232{
2233 ppp_recv_lock(ppp);
2234 if (!ppp->closing)
2235 ppp_receive_frame(ppp, skb, pch);
2236 else
2237 kfree_skb(skb);
2238 ppp_recv_unlock(ppp);
2239}
2240
2241/**
2242 * __ppp_decompress_proto - Decompress protocol field, slim version.
2243 * @skb: Socket buffer where protocol field should be decompressed. It must have
2244 * at least 1 byte of head room and 1 byte of linear data. First byte of
2245 * data must be a protocol field byte.
2246 *
2247 * Decompress protocol field in PPP header if it's compressed, e.g. when
2248 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2249 * length are done in this function.
2250 */
2251static void __ppp_decompress_proto(struct sk_buff *skb)
2252{
2253 if (ppp_skb_is_compressed_proto(skb))
2254 *(u8 *)skb_push(skb, 1) = 0x00;
2255}
2256
2257/**
2258 * ppp_decompress_proto - Check skb data room and decompress protocol field.
2259 * @skb: Socket buffer where protocol field should be decompressed. First byte
2260 * of data must be a protocol field byte.
2261 *
2262 * Decompress protocol field in PPP header if it's compressed, e.g. when
2263 * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2264 * sure that skb data room is sufficient for Protocol field, before and after
2265 * decompression.
2266 *
2267 * Return: true - decompressed successfully, false - not enough room in skb.
2268 */
2269static bool ppp_decompress_proto(struct sk_buff *skb)
2270{
2271 /* At least one byte should be present (if protocol is compressed) */
2272 if (!pskb_may_pull(skb, 1))
2273 return false;
2274
2275 __ppp_decompress_proto(skb);
2276
2277 /* Protocol field should occupy 2 bytes when not compressed */
2278 return pskb_may_pull(skb, 2);
2279}
2280
2281/* Attempt to handle a frame via. a bridged channel, if one exists.
2282 * If the channel is bridged, the frame is consumed by the bridge.
2283 * If not, the caller must handle the frame by normal recv mechanisms.
2284 * Returns true if the frame is consumed, false otherwise.
2285 */
2286static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2287{
2288 struct channel *pchb;
2289
2290 rcu_read_lock();
2291 pchb = rcu_dereference(pch->bridge);
2292 if (!pchb)
2293 goto out_rcu;
2294
2295 spin_lock_bh(&pchb->downl);
2296 if (!pchb->chan) {
2297 /* channel got unregistered */
2298 kfree_skb(skb);
2299 goto outl;
2300 }
2301
2302 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
2303 if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2304 kfree_skb(skb);
2305
2306outl:
2307 spin_unlock_bh(&pchb->downl);
2308out_rcu:
2309 rcu_read_unlock();
2310
2311 /* If pchb is set then we've consumed the packet */
2312 return !!pchb;
2313}
2314
2315void
2316ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2317{
2318 struct channel *pch = chan->ppp;
2319 struct ppp *ppp;
2320 int proto;
2321
2322 if (!pch) {
2323 kfree_skb(skb);
2324 return;
2325 }
2326
2327 /* If the channel is bridged, transmit via. bridge */
2328 if (ppp_channel_bridge_input(pch, skb))
2329 return;
2330
2331 rcu_read_lock_bh();
2332 ppp = rcu_dereference_bh(pch->ppp);
2333 if (!ppp_decompress_proto(skb)) {
2334 kfree_skb(skb);
2335 if (ppp) {
2336 DEV_STATS_INC(netdev_from_priv(ppp), rx_length_errors);
2337 ppp_receive_error(ppp);
2338 }
2339 goto done;
2340 }
2341
2342 proto = PPP_PROTO(skb);
2343 if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2344 /* put it on the channel queue */
2345 skb_queue_tail(&pch->file.rq, skb);
2346 /* drop old frames if queue too long */
2347 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2348 (skb = skb_dequeue(&pch->file.rq)))
2349 kfree_skb(skb);
2350 wake_up_interruptible(&pch->file.rwait);
2351 } else {
2352 ppp_do_recv(ppp, skb, pch);
2353 }
2354
2355done:
2356 rcu_read_unlock_bh();
2357}
2358
2359void
2360ppp_input_error(struct ppp_channel *chan)
2361{
2362 struct channel *pch = chan->ppp;
2363 struct ppp *ppp;
2364
2365 if (!pch)
2366 return;
2367
2368 rcu_read_lock_bh();
2369 ppp = rcu_dereference_bh(pch->ppp);
2370 if (ppp) {
2371 ppp_recv_lock(ppp);
2372 ppp_receive_error(ppp);
2373 ppp_recv_unlock(ppp);
2374 }
2375 rcu_read_unlock_bh();
2376}
2377
2378/*
2379 * We come in here to process a received frame.
2380 * The receive side of the ppp unit is locked.
2381 */
2382static void
2383ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2384{
2385 skb_checksum_complete_unset(skb);
2386#ifdef CONFIG_PPP_MULTILINK
2387 /* XXX do channel-level decompression here */
2388 if (PPP_PROTO(skb) == PPP_MP)
2389 ppp_receive_mp_frame(ppp, skb, pch);
2390 else
2391#endif /* CONFIG_PPP_MULTILINK */
2392 ppp_receive_nonmp_frame(ppp, skb);
2393}
2394
2395static void
2396ppp_receive_error(struct ppp *ppp)
2397{
2398 DEV_STATS_INC(netdev_from_priv(ppp), rx_errors);
2399 if (ppp->vj)
2400 slhc_toss(ppp->vj);
2401}
2402
2403static void
2404ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2405{
2406 struct net_device *dev = netdev_from_priv(ppp);
2407 struct sk_buff *ns;
2408 int proto, len, npi;
2409
2410 /*
2411 * Decompress the frame, if compressed.
2412 * Note that some decompressors need to see uncompressed frames
2413 * that come in as well as compressed frames.
2414 */
2415 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2416 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2417 skb = ppp_decompress_frame(ppp, skb);
2418
2419 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2420 goto err;
2421
2422 /* At this point the "Protocol" field MUST be decompressed, either in
2423 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2424 */
2425 proto = PPP_PROTO(skb);
2426 switch (proto) {
2427 case PPP_VJC_COMP:
2428 /* decompress VJ compressed packets */
2429 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2430 goto err;
2431
2432 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2433 /* copy to a new sk_buff with more tailroom */
2434 ns = dev_alloc_skb(skb->len + 128);
2435 if (!ns) {
2436 netdev_err(dev, "PPP: no memory (VJ decomp)\n");
2437 goto err;
2438 }
2439 skb_reserve(ns, 2);
2440 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
2441 consume_skb(skb);
2442 skb = ns;
2443 }
2444 else
2445 skb->ip_summed = CHECKSUM_NONE;
2446
2447 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
2448 if (len <= 0) {
2449 netdev_printk(KERN_DEBUG, dev,
2450 "PPP: VJ decompression error\n");
2451 goto err;
2452 }
2453 len += 2;
2454 if (len > skb->len)
2455 skb_put(skb, len - skb->len);
2456 else if (len < skb->len)
2457 skb_trim(skb, len);
2458 proto = PPP_IP;
2459 break;
2460
2461 case PPP_VJC_UNCOMP:
2462 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2463 goto err;
2464
2465 /* Until we fix the decompressor need to make sure
2466 * data portion is linear.
2467 */
2468 if (!pskb_may_pull(skb, skb->len))
2469 goto err;
2470
2471 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
2472 netdev_err(dev, "PPP: VJ uncompressed error\n");
2473 goto err;
2474 }
2475 proto = PPP_IP;
2476 break;
2477
2478 case PPP_CCP:
2479 ppp_ccp_peek(ppp, skb, 1);
2480 break;
2481 }
2482
2483 dev_sw_netstats_rx_add(dev, skb->len - PPP_PROTO_LEN);
2484
2485 npi = proto_to_npindex(proto);
2486 if (npi < 0) {
2487 /* control or unknown frame - pass it to pppd */
2488 skb_queue_tail(&ppp->file.rq, skb);
2489 /* limit queue length by dropping old frames */
2490 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2491 (skb = skb_dequeue(&ppp->file.rq)))
2492 kfree_skb(skb);
2493 /* wake up any process polling or blocking on read */
2494 wake_up_interruptible(&ppp->file.rwait);
2495
2496 } else {
2497 /* network protocol frame - give it to the kernel */
2498
2499#ifdef CONFIG_PPP_FILTER
2500 if (ppp->pass_filter || ppp->active_filter) {
2501 if (skb_unclone(skb, GFP_ATOMIC))
2502 goto err;
2503 /* Check if the packet passes the pass and active filters.
2504 * See comment for PPP_FILTER_INBOUND_TAG above.
2505 */
2506 *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG);
2507 if (ppp->pass_filter &&
2508 bpf_prog_run(ppp->pass_filter, skb) == 0) {
2509 if (READ_ONCE(ppp->debug) & 1)
2510 netdev_printk(KERN_DEBUG, dev,
2511 "PPP: inbound frame "
2512 "not passed\n");
2513 kfree_skb(skb);
2514 return;
2515 }
2516 if (!(ppp->active_filter &&
2517 bpf_prog_run(ppp->active_filter, skb) == 0))
2518 WRITE_ONCE(ppp->last_recv, jiffies);
2519 __skb_pull(skb, 2);
2520 } else
2521#endif /* CONFIG_PPP_FILTER */
2522 WRITE_ONCE(ppp->last_recv, jiffies);
2523
2524 if ((dev->flags & IFF_UP) == 0 ||
2525 READ_ONCE(ppp->npmode[npi]) != NPMODE_PASS) {
2526 kfree_skb(skb);
2527 } else {
2528 /* chop off protocol */
2529 skb_pull_rcsum(skb, 2);
2530 skb->dev = dev;
2531 skb->protocol = htons(npindex_to_ethertype[npi]);
2532 skb_reset_mac_header(skb);
2533 skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
2534 dev_net(dev)));
2535 netif_rx(skb);
2536 }
2537 }
2538 return;
2539
2540 err:
2541 kfree_skb(skb);
2542 ppp_receive_error(ppp);
2543}
2544
2545static struct sk_buff *
2546ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2547{
2548 int proto = PPP_PROTO(skb);
2549 struct sk_buff *ns;
2550 int len;
2551
2552 /* Until we fix all the decompressor's need to make sure
2553 * data portion is linear.
2554 */
2555 if (!pskb_may_pull(skb, skb->len))
2556 goto err;
2557
2558 if (proto == PPP_COMP) {
2559 int obuff_size;
2560
2561 switch(ppp->rcomp->compress_proto) {
2562 case CI_MPPE:
2563 obuff_size = ppp->mru + PPP_HDRLEN + 1;
2564 break;
2565 default:
2566 obuff_size = ppp->mru + PPP_HDRLEN;
2567 break;
2568 }
2569
2570 ns = dev_alloc_skb(obuff_size);
2571 if (!ns) {
2572 netdev_err(netdev_from_priv(ppp),
2573 "ppp_decompress_frame: no memory\n");
2574 goto err;
2575 }
2576 /* the decompressor still expects the A/C bytes in the hdr */
2577 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2578 skb->len + 2, ns->data, obuff_size);
2579 if (len < 0) {
2580 /* Pass the compressed frame to pppd as an
2581 error indication. */
2582 if (len == DECOMP_FATALERROR)
2583 ppp->rstate |= SC_DC_FERROR;
2584 kfree_skb(ns);
2585 goto err;
2586 }
2587
2588 consume_skb(skb);
2589 skb = ns;
2590 skb_put(skb, len);
2591 skb_pull(skb, 2); /* pull off the A/C bytes */
2592
2593 /* Don't call __ppp_decompress_proto() here, but instead rely on
2594 * corresponding algo (mppe/bsd/deflate) to decompress it.
2595 */
2596 } else {
2597 /* Uncompressed frame - pass to decompressor so it
2598 can update its dictionary if necessary. */
2599 if (ppp->rcomp->incomp)
2600 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2601 skb->len + 2);
2602 }
2603
2604 return skb;
2605
2606 err:
2607 ppp->rstate |= SC_DC_ERROR;
2608 ppp_receive_error(ppp);
2609 return skb;
2610}
2611
2612#ifdef CONFIG_PPP_MULTILINK
2613/*
2614 * Receive a multilink frame.
2615 * We put it on the reconstruction queue and then pull off
2616 * as many completed frames as we can.
2617 */
2618static void
2619ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2620{
2621 struct net_device *dev = netdev_from_priv(ppp);
2622 u32 mask, seq;
2623 struct channel *ch;
2624 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2625
2626 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
2627 goto err; /* no good, throw it away */
2628
2629 /* Decode sequence number and begin/end bits */
2630 if (ppp->flags & SC_MP_SHORTSEQ) {
2631 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2632 mask = 0xfff;
2633 } else {
2634 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2635 mask = 0xffffff;
2636 }
2637 PPP_MP_CB(skb)->BEbits = skb->data[2];
2638 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */
2639
2640 /*
2641 * Do protocol ID decompression on the first fragment of each packet.
2642 * We have to do that here, because ppp_receive_nonmp_frame() expects
2643 * decompressed protocol field.
2644 */
2645 if (PPP_MP_CB(skb)->BEbits & B)
2646 __ppp_decompress_proto(skb);
2647
2648 /*
2649 * Expand sequence number to 32 bits, making it as close
2650 * as possible to ppp->minseq.
2651 */
2652 seq |= ppp->minseq & ~mask;
2653 if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2654 seq += mask + 1;
2655 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2656 seq -= mask + 1; /* should never happen */
2657 PPP_MP_CB(skb)->sequence = seq;
2658 pch->lastseq = seq;
2659
2660 /*
2661 * If this packet comes before the next one we were expecting,
2662 * drop it.
2663 */
2664 if (seq_before(seq, ppp->nextseq)) {
2665 kfree_skb(skb);
2666 DEV_STATS_INC(dev, rx_dropped);
2667 ppp_receive_error(ppp);
2668 return;
2669 }
2670
2671 /*
2672 * Reevaluate minseq, the minimum over all channels of the
2673 * last sequence number received on each channel. Because of
2674 * the increasing sequence number rule, we know that any fragment
2675 * before `minseq' which hasn't arrived is never going to arrive.
2676 * The list of channels can't change because we have the receive
2677 * side of the ppp unit locked.
2678 */
2679 list_for_each_entry(ch, &ppp->channels, clist) {
2680 if (seq_before(ch->lastseq, seq))
2681 seq = ch->lastseq;
2682 }
2683 if (seq_before(ppp->minseq, seq))
2684 ppp->minseq = seq;
2685
2686 /* Put the fragment on the reconstruction queue */
2687 ppp_mp_insert(ppp, skb);
2688
2689 /* If the queue is getting long, don't wait any longer for packets
2690 before the start of the queue. */
2691 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
2692 struct sk_buff *mskb = skb_peek(&ppp->mrq);
2693 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2694 ppp->minseq = PPP_MP_CB(mskb)->sequence;
2695 }
2696
2697 /* Pull completed packets off the queue and receive them. */
2698 while ((skb = ppp_mp_reconstruct(ppp))) {
2699 if (pskb_may_pull(skb, 2))
2700 ppp_receive_nonmp_frame(ppp, skb);
2701 else {
2702 DEV_STATS_INC(dev, rx_length_errors);
2703 kfree_skb(skb);
2704 ppp_receive_error(ppp);
2705 }
2706 }
2707
2708 return;
2709
2710 err:
2711 kfree_skb(skb);
2712 ppp_receive_error(ppp);
2713}
2714
2715/*
2716 * Insert a fragment on the MP reconstruction queue.
2717 * The queue is ordered by increasing sequence number.
2718 */
2719static void
2720ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2721{
2722 struct sk_buff *p;
2723 struct sk_buff_head *list = &ppp->mrq;
2724 u32 seq = PPP_MP_CB(skb)->sequence;
2725
2726 /* N.B. we don't need to lock the list lock because we have the
2727 ppp unit receive-side lock. */
2728 skb_queue_walk(list, p) {
2729 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2730 break;
2731 }
2732 __skb_queue_before(list, p, skb);
2733}
2734
2735/*
2736 * Reconstruct a packet from the MP fragment queue.
2737 * We go through increasing sequence numbers until we find a
2738 * complete packet, or we get to the sequence number for a fragment
2739 * which hasn't arrived but might still do so.
2740 */
2741static struct sk_buff *
2742ppp_mp_reconstruct(struct ppp *ppp)
2743{
2744 struct net_device *dev = netdev_from_priv(ppp);
2745 u32 seq = ppp->nextseq;
2746 u32 minseq = ppp->minseq;
2747 struct sk_buff_head *list = &ppp->mrq;
2748 struct sk_buff *p, *tmp;
2749 struct sk_buff *head, *tail;
2750 struct sk_buff *skb = NULL;
2751 int lost = 0, len = 0;
2752
2753 if (ppp->mrru == 0) /* do nothing until mrru is set */
2754 return NULL;
2755 head = __skb_peek(list);
2756 tail = NULL;
2757 skb_queue_walk_safe(list, p, tmp) {
2758 again:
2759 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2760 /* this can't happen, anyway ignore the skb */
2761 netdev_err(dev, "ppp_mp_reconstruct bad seq %u < %u\n",
2762 PPP_MP_CB(p)->sequence, seq);
2763 __skb_unlink(p, list);
2764 kfree_skb(p);
2765 continue;
2766 }
2767 if (PPP_MP_CB(p)->sequence != seq) {
2768 u32 oldseq;
2769 /* Fragment `seq' is missing. If it is after
2770 minseq, it might arrive later, so stop here. */
2771 if (seq_after(seq, minseq))
2772 break;
2773 /* Fragment `seq' is lost, keep going. */
2774 lost = 1;
2775 oldseq = seq;
2776 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2777 minseq + 1: PPP_MP_CB(p)->sequence;
2778
2779 if (READ_ONCE(ppp->debug) & 1)
2780 netdev_printk(KERN_DEBUG, dev,
2781 "lost frag %u..%u\n",
2782 oldseq, seq-1);
2783
2784 goto again;
2785 }
2786
2787 /*
2788 * At this point we know that all the fragments from
2789 * ppp->nextseq to seq are either present or lost.
2790 * Also, there are no complete packets in the queue
2791 * that have no missing fragments and end before this
2792 * fragment.
2793 */
2794
2795 /* B bit set indicates this fragment starts a packet */
2796 if (PPP_MP_CB(p)->BEbits & B) {
2797 head = p;
2798 lost = 0;
2799 len = 0;
2800 }
2801
2802 len += p->len;
2803
2804 /* Got a complete packet yet? */
2805 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2806 (PPP_MP_CB(head)->BEbits & B)) {
2807 if (len > ppp->mrru + 2) {
2808 DEV_STATS_INC(dev, rx_length_errors);
2809 netdev_printk(KERN_DEBUG, dev,
2810 "PPP: reconstructed packet"
2811 " is too long (%d)\n", len);
2812 } else {
2813 tail = p;
2814 break;
2815 }
2816 ppp->nextseq = seq + 1;
2817 }
2818
2819 /*
2820 * If this is the ending fragment of a packet,
2821 * and we haven't found a complete valid packet yet,
2822 * we can discard up to and including this fragment.
2823 */
2824 if (PPP_MP_CB(p)->BEbits & E) {
2825 struct sk_buff *tmp2;
2826
2827 skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2828 if (READ_ONCE(ppp->debug) & 1)
2829 netdev_printk(KERN_DEBUG, dev,
2830 "discarding frag %u\n",
2831 PPP_MP_CB(p)->sequence);
2832 __skb_unlink(p, list);
2833 kfree_skb(p);
2834 }
2835 head = skb_peek(list);
2836 if (!head)
2837 break;
2838 }
2839 ++seq;
2840 }
2841
2842 /* If we have a complete packet, copy it all into one skb. */
2843 if (tail != NULL) {
2844 /* If we have discarded any fragments,
2845 signal a receive error. */
2846 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2847 skb_queue_walk_safe(list, p, tmp) {
2848 if (p == head)
2849 break;
2850 if (READ_ONCE(ppp->debug) & 1)
2851 netdev_printk(KERN_DEBUG, dev,
2852 "discarding frag %u\n",
2853 PPP_MP_CB(p)->sequence);
2854 __skb_unlink(p, list);
2855 kfree_skb(p);
2856 }
2857
2858 if (READ_ONCE(ppp->debug) & 1)
2859 netdev_printk(KERN_DEBUG, dev,
2860 " missed pkts %u..%u\n",
2861 ppp->nextseq,
2862 PPP_MP_CB(head)->sequence-1);
2863 DEV_STATS_INC(dev, rx_dropped);
2864 ppp_receive_error(ppp);
2865 }
2866
2867 skb = head;
2868 if (head != tail) {
2869 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2870 p = skb_queue_next(list, head);
2871 __skb_unlink(skb, list);
2872 skb_queue_walk_from_safe(list, p, tmp) {
2873 __skb_unlink(p, list);
2874 *fragpp = p;
2875 p->next = NULL;
2876 fragpp = &p->next;
2877
2878 skb->len += p->len;
2879 skb->data_len += p->len;
2880 skb->truesize += p->truesize;
2881
2882 if (p == tail)
2883 break;
2884 }
2885 } else {
2886 __skb_unlink(skb, list);
2887 }
2888
2889 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2890 }
2891
2892 return skb;
2893}
2894#endif /* CONFIG_PPP_MULTILINK */
2895
2896/*
2897 * Channel interface.
2898 */
2899
2900/* Create a new, unattached ppp channel. */
2901int ppp_register_channel(struct ppp_channel *chan)
2902{
2903 return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2904}
2905
2906/* Create a new, unattached ppp channel for specified net. */
2907int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2908{
2909 struct channel *pch;
2910 struct ppp_net *pn;
2911
2912 pch = kzalloc_obj(struct channel);
2913 if (!pch)
2914 return -ENOMEM;
2915
2916 pn = ppp_pernet(net);
2917
2918 pch->chan = chan;
2919 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
2920 chan->ppp = pch;
2921 init_ppp_file(&pch->file, CHANNEL);
2922 pch->file.hdrlen = chan->hdrlen;
2923#ifdef CONFIG_PPP_MULTILINK
2924 pch->lastseq = -1;
2925#endif /* CONFIG_PPP_MULTILINK */
2926 mutex_init(&pch->chan_sem);
2927 spin_lock_init(&pch->downl);
2928 spin_lock_init(&pch->upl);
2929
2930 spin_lock_bh(&pn->all_channels_lock);
2931 pch->file.index = ++pn->last_channel_index;
2932 list_add(&pch->list, &pn->new_channels);
2933 atomic_inc(&channel_count);
2934 spin_unlock_bh(&pn->all_channels_lock);
2935
2936 return 0;
2937}
2938
2939/*
2940 * Return the index of a channel.
2941 */
2942int ppp_channel_index(struct ppp_channel *chan)
2943{
2944 struct channel *pch = chan->ppp;
2945
2946 if (pch)
2947 return pch->file.index;
2948 return -1;
2949}
2950
2951/*
2952 * Return the PPP unit number to which a channel is connected.
2953 */
2954int ppp_unit_number(struct ppp_channel *chan)
2955{
2956 struct channel *pch = chan->ppp;
2957 struct ppp *ppp;
2958 int unit = -1;
2959
2960 if (pch) {
2961 rcu_read_lock();
2962 ppp = rcu_dereference(pch->ppp);
2963 if (ppp)
2964 unit = ppp->file.index;
2965 rcu_read_unlock();
2966 }
2967 return unit;
2968}
2969
2970/*
2971 * Return the PPP device interface name of a channel.
2972 * Caller must hold RCU read lock.
2973 */
2974char *ppp_dev_name(struct ppp_channel *chan)
2975{
2976 struct channel *pch = chan->ppp;
2977 char *name = NULL;
2978 struct ppp *ppp;
2979
2980 if (pch) {
2981 ppp = rcu_dereference(pch->ppp);
2982 if (ppp)
2983 name = netdev_from_priv(ppp)->name;
2984 }
2985 return name;
2986}
2987
2988
2989/*
2990 * Disconnect a channel from the generic layer.
2991 * This must be called in process context.
2992 */
2993void
2994ppp_unregister_channel(struct ppp_channel *chan)
2995{
2996 struct channel *pch = chan->ppp;
2997 struct ppp_net *pn;
2998
2999 if (!pch)
3000 return; /* should never happen */
3001
3002 chan->ppp = NULL;
3003
3004 /*
3005 * This ensures that we have returned from any calls into
3006 * the channel's start_xmit or ioctl routine before we proceed.
3007 */
3008 ppp_disconnect_channel(pch);
3009 mutex_lock(&pch->chan_sem);
3010 spin_lock_bh(&pch->downl);
3011 pch->chan = NULL;
3012 spin_unlock_bh(&pch->downl);
3013 mutex_unlock(&pch->chan_sem);
3014
3015 pn = ppp_pernet(pch->chan_net);
3016 spin_lock_bh(&pn->all_channels_lock);
3017 list_del(&pch->list);
3018 spin_unlock_bh(&pn->all_channels_lock);
3019
3020 ppp_unbridge_channels(pch);
3021
3022 pch->file.dead = 1;
3023 wake_up_interruptible(&pch->file.rwait);
3024
3025 ppp_release_channel(pch);
3026}
3027
3028/*
3029 * Callback from a channel when it can accept more to transmit.
3030 * This should be called at BH/softirq level, not interrupt level.
3031 */
3032void
3033ppp_output_wakeup(struct ppp_channel *chan)
3034{
3035 struct channel *pch = chan->ppp;
3036
3037 if (!pch)
3038 return;
3039 ppp_channel_push(pch);
3040}
3041
3042/*
3043 * Compression control.
3044 */
3045
3046/* Process the PPPIOCSCOMPRESS ioctl. */
3047static int
3048ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3049{
3050 int err = -EFAULT;
3051 struct compressor *cp, *ocomp;
3052 void *state, *ostate;
3053 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3054
3055 if (data->length > CCP_MAX_OPTION_LENGTH)
3056 goto out;
3057 if (copy_from_user(ccp_option, data->ptr, data->length))
3058 goto out;
3059
3060 err = -EINVAL;
3061 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3062 goto out;
3063
3064 cp = try_then_request_module(
3065 find_compressor(ccp_option[0]),
3066 "ppp-compress-%d", ccp_option[0]);
3067 if (!cp)
3068 goto out;
3069
3070 err = -ENOBUFS;
3071 if (data->transmit) {
3072 state = cp->comp_alloc(ccp_option, data->length);
3073 if (state) {
3074 ppp_xmit_lock(ppp);
3075 ppp->xstate &= ~SC_COMP_RUN;
3076 ocomp = ppp->xcomp;
3077 ostate = ppp->xc_state;
3078 ppp->xcomp = cp;
3079 ppp->xc_state = state;
3080 ppp_xmit_unlock(ppp);
3081 if (ostate) {
3082 ocomp->comp_free(ostate);
3083 module_put(ocomp->owner);
3084 }
3085 err = 0;
3086 } else
3087 module_put(cp->owner);
3088
3089 } else {
3090 state = cp->decomp_alloc(ccp_option, data->length);
3091 if (state) {
3092 ppp_recv_lock(ppp);
3093 ppp->rstate &= ~SC_DECOMP_RUN;
3094 ocomp = ppp->rcomp;
3095 ostate = ppp->rc_state;
3096 ppp->rcomp = cp;
3097 ppp->rc_state = state;
3098 ppp_recv_unlock(ppp);
3099 if (ostate) {
3100 ocomp->decomp_free(ostate);
3101 module_put(ocomp->owner);
3102 }
3103 err = 0;
3104 } else
3105 module_put(cp->owner);
3106 }
3107
3108 out:
3109 return err;
3110}
3111
3112/*
3113 * Look at a CCP packet and update our state accordingly.
3114 * We assume the caller has the xmit or recv path locked.
3115 */
3116static void
3117ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3118{
3119 unsigned char *dp;
3120 int len;
3121
3122 if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3123 return; /* no header */
3124 dp = skb->data + 2;
3125
3126 switch (CCP_CODE(dp)) {
3127 case CCP_CONFREQ:
3128
3129 /* A ConfReq starts negotiation of compression
3130 * in one direction of transmission,
3131 * and hence brings it down...but which way?
3132 *
3133 * Remember:
3134 * A ConfReq indicates what the sender would like to receive
3135 */
3136 if(inbound)
3137 /* He is proposing what I should send */
3138 ppp->xstate &= ~SC_COMP_RUN;
3139 else
3140 /* I am proposing to what he should send */
3141 ppp->rstate &= ~SC_DECOMP_RUN;
3142
3143 break;
3144
3145 case CCP_TERMREQ:
3146 case CCP_TERMACK:
3147 /*
3148 * CCP is going down, both directions of transmission
3149 */
3150 ppp->rstate &= ~SC_DECOMP_RUN;
3151 ppp->xstate &= ~SC_COMP_RUN;
3152 break;
3153
3154 case CCP_CONFACK:
3155 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3156 break;
3157 len = CCP_LENGTH(dp);
3158 if (!pskb_may_pull(skb, len + 2))
3159 return; /* too short */
3160 dp += CCP_HDRLEN;
3161 len -= CCP_HDRLEN;
3162 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3163 break;
3164 if (inbound) {
3165 /* we will start receiving compressed packets */
3166 if (!ppp->rc_state)
3167 break;
3168 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3169 ppp->file.index, 0, ppp->mru,
3170 READ_ONCE(ppp->debug))) {
3171 ppp->rstate |= SC_DECOMP_RUN;
3172 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3173 }
3174 } else {
3175 /* we will soon start sending compressed packets */
3176 if (!ppp->xc_state)
3177 break;
3178 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3179 ppp->file.index, 0,
3180 READ_ONCE(ppp->debug)))
3181 ppp->xstate |= SC_COMP_RUN;
3182 }
3183 break;
3184
3185 case CCP_RESETACK:
3186 /* reset the [de]compressor */
3187 if ((ppp->flags & SC_CCP_UP) == 0)
3188 break;
3189 if (inbound) {
3190 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3191 ppp->rcomp->decomp_reset(ppp->rc_state);
3192 ppp->rstate &= ~SC_DC_ERROR;
3193 }
3194 } else {
3195 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3196 ppp->xcomp->comp_reset(ppp->xc_state);
3197 }
3198 break;
3199 }
3200}
3201
3202/* Free up compression resources. */
3203static void
3204ppp_ccp_closed(struct ppp *ppp)
3205{
3206 void *xstate, *rstate;
3207 struct compressor *xcomp, *rcomp;
3208
3209 ppp_lock(ppp);
3210 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3211 ppp->xstate = 0;
3212 xcomp = ppp->xcomp;
3213 xstate = ppp->xc_state;
3214 ppp->xc_state = NULL;
3215 ppp->rstate = 0;
3216 rcomp = ppp->rcomp;
3217 rstate = ppp->rc_state;
3218 ppp->rc_state = NULL;
3219 ppp_unlock(ppp);
3220
3221 if (xstate) {
3222 xcomp->comp_free(xstate);
3223 module_put(xcomp->owner);
3224 }
3225 if (rstate) {
3226 rcomp->decomp_free(rstate);
3227 module_put(rcomp->owner);
3228 }
3229}
3230
3231/* List of compressors. */
3232static LIST_HEAD(compressor_list);
3233static DEFINE_SPINLOCK(compressor_list_lock);
3234
3235struct compressor_entry {
3236 struct list_head list;
3237 struct compressor *comp;
3238};
3239
3240static struct compressor_entry *
3241find_comp_entry(int proto)
3242{
3243 struct compressor_entry *ce;
3244
3245 list_for_each_entry(ce, &compressor_list, list) {
3246 if (ce->comp->compress_proto == proto)
3247 return ce;
3248 }
3249 return NULL;
3250}
3251
3252/* Register a compressor */
3253int
3254ppp_register_compressor(struct compressor *cp)
3255{
3256 struct compressor_entry *ce;
3257 int ret;
3258 spin_lock(&compressor_list_lock);
3259 ret = -EEXIST;
3260 if (find_comp_entry(cp->compress_proto))
3261 goto out;
3262 ret = -ENOMEM;
3263 ce = kmalloc_obj(struct compressor_entry, GFP_ATOMIC);
3264 if (!ce)
3265 goto out;
3266 ret = 0;
3267 ce->comp = cp;
3268 list_add(&ce->list, &compressor_list);
3269 out:
3270 spin_unlock(&compressor_list_lock);
3271 return ret;
3272}
3273
3274/* Unregister a compressor */
3275void
3276ppp_unregister_compressor(struct compressor *cp)
3277{
3278 struct compressor_entry *ce;
3279
3280 spin_lock(&compressor_list_lock);
3281 ce = find_comp_entry(cp->compress_proto);
3282 if (ce && ce->comp == cp) {
3283 list_del(&ce->list);
3284 kfree(ce);
3285 }
3286 spin_unlock(&compressor_list_lock);
3287}
3288
3289/* Find a compressor. */
3290static struct compressor *
3291find_compressor(int type)
3292{
3293 struct compressor_entry *ce;
3294 struct compressor *cp = NULL;
3295
3296 spin_lock(&compressor_list_lock);
3297 ce = find_comp_entry(type);
3298 if (ce) {
3299 cp = ce->comp;
3300 if (!try_module_get(cp->owner))
3301 cp = NULL;
3302 }
3303 spin_unlock(&compressor_list_lock);
3304 return cp;
3305}
3306
3307/*
3308 * Miscelleneous stuff.
3309 */
3310
3311static void
3312ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3313{
3314 struct net_device *dev = netdev_from_priv(ppp);
3315 struct slcompress *vj = ppp->vj;
3316 int cpu;
3317
3318 memset(st, 0, sizeof(*st));
3319 for_each_possible_cpu(cpu) {
3320 struct pcpu_sw_netstats *p = per_cpu_ptr(dev->tstats, cpu);
3321 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
3322
3323 rx_packets = u64_stats_read(&p->rx_packets);
3324 rx_bytes = u64_stats_read(&p->rx_bytes);
3325 tx_packets = u64_stats_read(&p->tx_packets);
3326 tx_bytes = u64_stats_read(&p->tx_bytes);
3327
3328 st->p.ppp_ipackets += rx_packets;
3329 st->p.ppp_ibytes += rx_bytes;
3330 st->p.ppp_opackets += tx_packets;
3331 st->p.ppp_obytes += tx_bytes;
3332 }
3333 st->p.ppp_ierrors = DEV_STATS_READ(dev, rx_errors);
3334 st->p.ppp_oerrors = DEV_STATS_READ(dev, tx_errors);
3335 if (!vj)
3336 return;
3337 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3338 st->vj.vjs_compressed = vj->sls_o_compressed;
3339 st->vj.vjs_searches = vj->sls_o_searches;
3340 st->vj.vjs_misses = vj->sls_o_misses;
3341 st->vj.vjs_errorin = vj->sls_i_error;
3342 st->vj.vjs_tossed = vj->sls_i_tossed;
3343 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3344 st->vj.vjs_compressedin = vj->sls_i_compressed;
3345}
3346
3347/*
3348 * Stuff for handling the lists of ppp units and channels
3349 * and for initialization.
3350 */
3351
3352/*
3353 * Create a new ppp interface unit. Fails if it can't allocate memory
3354 * or if there is already a unit with the requested number.
3355 * unit == -1 means allocate a new number.
3356 */
3357static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3358{
3359 struct ppp_config conf = {
3360 .file = file,
3361 .unit = *unit,
3362 .ifname_is_set = false,
3363 };
3364 struct net_device *dev;
3365 struct ppp *ppp;
3366 int err;
3367
3368 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3369 if (!dev) {
3370 err = -ENOMEM;
3371 goto err;
3372 }
3373 dev_net_set(dev, net);
3374 dev->rtnl_link_ops = &ppp_link_ops;
3375
3376 rtnl_lock();
3377
3378 err = ppp_dev_configure(net, dev, &conf);
3379 if (err < 0)
3380 goto err_dev;
3381 ppp = netdev_priv(dev);
3382 *unit = ppp->file.index;
3383
3384 rtnl_unlock();
3385
3386 return 0;
3387
3388err_dev:
3389 rtnl_unlock();
3390 free_netdev(dev);
3391err:
3392 return err;
3393}
3394
3395/*
3396 * Initialize a ppp_file structure.
3397 */
3398static void
3399init_ppp_file(struct ppp_file *pf, int kind)
3400{
3401 pf->kind = kind;
3402 skb_queue_head_init(&pf->xq);
3403 skb_queue_head_init(&pf->rq);
3404 refcount_set(&pf->refcnt, 1);
3405 init_waitqueue_head(&pf->rwait);
3406}
3407
3408/*
3409 * Drop a reference to a ppp unit and free its memory if the refcount reaches
3410 * zero.
3411 */
3412static void ppp_release_interface(struct ppp *ppp)
3413{
3414 struct net_device *dev = netdev_from_priv(ppp);
3415
3416 if (!refcount_dec_and_test(&ppp->file.refcnt))
3417 return;
3418
3419 atomic_dec(&ppp_unit_count);
3420
3421 if (!ppp->file.dead || ppp->n_channels) {
3422 /* "can't happen" */
3423 netdev_err(dev, "ppp: destroying ppp struct %p "
3424 "but dead=%d n_channels=%d !\n",
3425 ppp, ppp->file.dead, ppp->n_channels);
3426 return;
3427 }
3428
3429 ppp_ccp_closed(ppp);
3430 if (ppp->vj) {
3431 slhc_free(ppp->vj);
3432 ppp->vj = NULL;
3433 }
3434 skb_queue_purge(&ppp->file.xq);
3435 skb_queue_purge(&ppp->file.rq);
3436#ifdef CONFIG_PPP_MULTILINK
3437 skb_queue_purge(&ppp->mrq);
3438#endif /* CONFIG_PPP_MULTILINK */
3439#ifdef CONFIG_PPP_FILTER
3440 if (ppp->pass_filter) {
3441 bpf_prog_destroy(ppp->pass_filter);
3442 ppp->pass_filter = NULL;
3443 }
3444
3445 if (ppp->active_filter) {
3446 bpf_prog_destroy(ppp->active_filter);
3447 ppp->active_filter = NULL;
3448 }
3449#endif /* CONFIG_PPP_FILTER */
3450
3451 free_percpu(ppp->xmit_recursion);
3452
3453 free_netdev(dev);
3454}
3455
3456/*
3457 * Locate an existing ppp unit.
3458 * The caller should have locked the all_ppp_mutex.
3459 */
3460static struct ppp *
3461ppp_find_unit(struct ppp_net *pn, int unit)
3462{
3463 return unit_find(&pn->units_idr, unit);
3464}
3465
3466/*
3467 * Locate an existing ppp channel.
3468 * The caller should have locked the all_channels_lock.
3469 * First we look in the new_channels list, then in the
3470 * all_channels list. If found in the new_channels list,
3471 * we move it to the all_channels list. This is for speed
3472 * when we have a lot of channels in use.
3473 */
3474static struct channel *
3475ppp_find_channel(struct ppp_net *pn, int unit)
3476{
3477 struct channel *pch;
3478
3479 list_for_each_entry(pch, &pn->new_channels, list) {
3480 if (pch->file.index == unit) {
3481 list_move(&pch->list, &pn->all_channels);
3482 return pch;
3483 }
3484 }
3485
3486 list_for_each_entry(pch, &pn->all_channels, list) {
3487 if (pch->file.index == unit)
3488 return pch;
3489 }
3490
3491 return NULL;
3492}
3493
3494/*
3495 * Connect a PPP channel to a PPP interface unit.
3496 */
3497static int
3498ppp_connect_channel(struct channel *pch, int unit)
3499{
3500 struct net_device *dev;
3501 struct ppp *ppp;
3502 struct ppp_net *pn;
3503 int ret = -ENXIO;
3504 int hdrlen;
3505
3506 pn = ppp_pernet(pch->chan_net);
3507
3508 mutex_lock(&pn->all_ppp_mutex);
3509 ppp = ppp_find_unit(pn, unit);
3510 if (!ppp)
3511 goto out;
3512 dev = netdev_from_priv(ppp);
3513 spin_lock(&pch->upl);
3514 ret = -EINVAL;
3515 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
3516 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3517 goto outl;
3518
3519 ppp_lock(ppp);
3520 spin_lock_bh(&pch->downl);
3521 if (!pch->chan) {
3522 /* Don't connect unregistered channels */
3523 spin_unlock_bh(&pch->downl);
3524 ppp_unlock(ppp);
3525 ret = -ENOTCONN;
3526 goto outl;
3527 }
3528 if (pch->chan->direct_xmit)
3529 dev->priv_flags |= IFF_NO_QUEUE;
3530 else
3531 dev->priv_flags &= ~IFF_NO_QUEUE;
3532 spin_unlock_bh(&pch->downl);
3533 if (pch->file.hdrlen > ppp->file.hdrlen)
3534 ppp->file.hdrlen = pch->file.hdrlen;
3535 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
3536 if (hdrlen > dev->hard_header_len)
3537 dev->hard_header_len = hdrlen;
3538 list_add_tail_rcu(&pch->clist, &ppp->channels);
3539 ++ppp->n_channels;
3540 rcu_assign_pointer(pch->ppp, ppp);
3541 refcount_inc(&ppp->file.refcnt);
3542 ppp_unlock(ppp);
3543 ret = 0;
3544
3545 outl:
3546 spin_unlock(&pch->upl);
3547 out:
3548 mutex_unlock(&pn->all_ppp_mutex);
3549 return ret;
3550}
3551
3552/*
3553 * Disconnect a channel from its ppp unit.
3554 */
3555static int
3556ppp_disconnect_channel(struct channel *pch)
3557{
3558 struct ppp *ppp;
3559 int err = -EINVAL;
3560
3561 spin_lock(&pch->upl);
3562 ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl));
3563 spin_unlock(&pch->upl);
3564 if (ppp) {
3565 /* remove it from the ppp unit's list */
3566 ppp_lock(ppp);
3567 list_del_rcu(&pch->clist);
3568 if (--ppp->n_channels == 0)
3569 wake_up_interruptible(&ppp->file.rwait);
3570 ppp_unlock(ppp);
3571 synchronize_net();
3572 ppp_release_interface(ppp);
3573 err = 0;
3574 }
3575 return err;
3576}
3577
3578/* Purge after the grace period: a late ppp_input() may still queue an
3579 * skb on pch->file.rq before the last RCU reader drains.
3580 */
3581static void ppp_release_channel_free(struct rcu_head *rcu)
3582{
3583 struct channel *pch = container_of(rcu, struct channel, rcu);
3584
3585 skb_queue_purge(&pch->file.xq);
3586 skb_queue_purge(&pch->file.rq);
3587 kfree(pch);
3588}
3589
3590/*
3591 * Drop a reference to a ppp channel and free its memory if the refcount reaches
3592 * zero.
3593 */
3594static void ppp_release_channel(struct channel *pch)
3595{
3596 if (!refcount_dec_and_test(&pch->file.refcnt))
3597 return;
3598
3599 put_net_track(pch->chan_net, &pch->ns_tracker);
3600 pch->chan_net = NULL;
3601
3602 atomic_dec(&channel_count);
3603
3604 if (!pch->file.dead) {
3605 /* "can't happen" */
3606 pr_err("ppp: destroying undead channel %p !\n", pch);
3607 return;
3608 }
3609 mutex_destroy(&pch->chan_sem);
3610 call_rcu(&pch->rcu, ppp_release_channel_free);
3611}
3612
3613static void __exit ppp_cleanup(void)
3614{
3615 /* should never happen */
3616 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
3617 pr_err("PPP: removing module but units remain!\n");
3618 rtnl_link_unregister(&ppp_link_ops);
3619 unregister_chrdev(PPP_MAJOR, "ppp");
3620 device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0));
3621 class_unregister(&ppp_class);
3622 unregister_pernet_device(&ppp_net_ops);
3623 rcu_barrier(); /* wait for RCU callbacks before module unload */
3624}
3625
3626/*
3627 * Units handling. Caller must protect concurrent access
3628 * by holding all_ppp_mutex
3629 */
3630
3631/* associate pointer with specified number */
3632static int unit_set(struct idr *p, void *ptr, int n)
3633{
3634 int unit;
3635
3636 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
3637 if (unit == -ENOSPC)
3638 unit = -EINVAL;
3639 return unit;
3640}
3641
3642/* get new free unit number and associate pointer with it */
3643static int unit_get(struct idr *p, void *ptr, int min)
3644{
3645 return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
3646}
3647
3648/* put unit number back to a pool */
3649static void unit_put(struct idr *p, int n)
3650{
3651 idr_remove(p, n);
3652}
3653
3654/* get pointer associated with the number */
3655static void *unit_find(struct idr *p, int n)
3656{
3657 return idr_find(p, n);
3658}
3659
3660/* Module/initialization stuff */
3661
3662module_init(ppp_init);
3663module_exit(ppp_cleanup);
3664
3665EXPORT_SYMBOL(ppp_register_net_channel);
3666EXPORT_SYMBOL(ppp_register_channel);
3667EXPORT_SYMBOL(ppp_unregister_channel);
3668EXPORT_SYMBOL(ppp_channel_index);
3669EXPORT_SYMBOL(ppp_unit_number);
3670EXPORT_SYMBOL(ppp_dev_name);
3671EXPORT_SYMBOL(ppp_input);
3672EXPORT_SYMBOL(ppp_input_error);
3673EXPORT_SYMBOL(ppp_output_wakeup);
3674EXPORT_SYMBOL(ppp_register_compressor);
3675EXPORT_SYMBOL(ppp_unregister_compressor);
3676MODULE_DESCRIPTION("Generic PPP layer driver");
3677MODULE_LICENSE("GPL");
3678MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3679MODULE_ALIAS_RTNL_LINK("ppp");
3680MODULE_ALIAS("devname:ppp");