1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* Generic PPP layer for Linux.
4	*
5	* Copyright 1999-2002 Paul Mackerras.
6	*
7	* The generic PPP layer handles the PPP network interfaces, the
8	* /dev/ppp device, packet and VJ compression, and multilink.
9	* It talks to PPP `channels' via the interface defined in
10	* include/linux/ppp_channel.h. Channels provide the basic means for
11	* sending and receiving PPP frames on some kind of communications
12	* channel.
13	*
14	* Part of the code in this driver was inspired by the old async-only
15	* PPP driver, written by Michael Callahan and Al Longyear, and
16	* subsequently hacked by Paul Mackerras.
17	*
18	* ==FILEVERSION 20041108==
19	*/
20
21	#include <linux/module.h>
22	#include <linux/kernel.h>
23	#include <linux/sched/signal.h>
24	#include <linux/kmod.h>
25	#include <linux/init.h>
26	#include <linux/list.h>
27	#include <linux/idr.h>
28	#include <linux/netdevice.h>
29	#include <linux/poll.h>
30	#include <linux/ppp_defs.h>
31	#include <linux/filter.h>
32	#include <linux/ppp-ioctl.h>
33	#include <linux/ppp_channel.h>
34	#include <linux/ppp-comp.h>
35	#include <linux/skbuff.h>
36	#include <linux/rtnetlink.h>
37	#include <linux/if_arp.h>
38	#include <linux/ip.h>
39	#include <linux/tcp.h>
40	#include <linux/spinlock.h>
41	#include <linux/rwsem.h>
42	#include <linux/stddef.h>
43	#include <linux/device.h>
44	#include <linux/mutex.h>
45	#include <linux/slab.h>
46	#include <linux/file.h>
47	#include <asm/unaligned.h>
48	#include <net/slhc_vj.h>
49	#include <linux/atomic.h>
50	#include <linux/refcount.h>
51
52	#include <linux/nsproxy.h>
53	#include <net/net_namespace.h>
54	#include <net/netns/generic.h>
55
56	#define PPP_VERSION "2.4.2"
57
58	/*
59	* Network protocols we support.
60	*/
61	#define NP_IP 0 /* Internet Protocol V4 */
62	#define NP_IPV6 1 /* Internet Protocol V6 */
63	#define NP_IPX 2 /* IPX protocol */
64	#define NP_AT 3 /* Appletalk protocol */
65	#define NP_MPLS_UC 4 /* MPLS unicast */
66	#define NP_MPLS_MC 5 /* MPLS multicast */
67	#define NUM_NP 6 /* Number of NPs. */
68
69	#define MPHDRLEN 6 /* multilink protocol header length */
70	#define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
71
72	#define PPP_PROTO_LEN 2
73
74	/*
75	* An instance of /dev/ppp can be associated with either a ppp
76	* interface unit or a ppp channel. In both cases, file->private_data
77	* points to one of these.
78	*/
79	struct ppp_file {
80	enum {
81	INTERFACE=1, CHANNEL
82	} kind;
83	struct sk_buff_head xq; /* pppd transmit queue */
84	struct sk_buff_head rq; /* receive queue for pppd */
85	wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
86	refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
87	int hdrlen; /* space to leave for headers */
88	int index; /* interface unit / channel number */
89	int dead; /* unit/channel has been shut down */
90	};
91
92	#define PF_TO_X(pf, X) container_of(pf, X, file)
93
94	#define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
95	#define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
96
97	/*
98	* Data structure to hold primary network stats for which
99	* we want to use 64 bit storage. Other network stats
100	* are stored in dev->stats of the ppp strucute.
101	*/
102	struct ppp_link_stats {
103	u64 rx_packets;
104	u64 tx_packets;
105	u64 rx_bytes;
106	u64 tx_bytes;
107	};
108
109	/*
110	* Data structure describing one ppp unit.
111	* A ppp unit corresponds to a ppp network interface device
112	* and represents a multilink bundle.
113	* It can have 0 or more ppp channels connected to it.
114	*/
115	struct ppp {
116	struct ppp_file file; /* stuff for read/write/poll 0 */
117	struct file *owner; /* file that owns this unit 48 */
118	struct list_head channels; /* list of attached channels 4c */
119	int n_channels; /* how many channels are attached 54 */
120	spinlock_t rlock; /* lock for receive side 58 */
121	spinlock_t wlock; /* lock for transmit side 5c */
122	int __percpu *xmit_recursion; /* xmit recursion detect */
123	int mru; /* max receive unit 60 */
124	unsigned int flags; /* control bits 64 */
125	unsigned int xstate; /* transmit state bits 68 */
126	unsigned int rstate; /* receive state bits 6c */
127	int debug; /* debug flags 70 */
128	struct slcompress *vj; /* state for VJ header compression */
129	enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
130	struct sk_buff *xmit_pending; /* a packet ready to go out 88 */
131	struct compressor *xcomp; /* transmit packet compressor 8c */
132	void *xc_state; /* its internal state 90 */
133	struct compressor *rcomp; /* receive decompressor 94 */
134	void *rc_state; /* its internal state 98 */
135	unsigned long last_xmit; /* jiffies when last pkt sent 9c */
136	unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
137	struct net_device *dev; /* network interface device a4 */
138	int closing; /* is device closing down? a8 */
139	#ifdef CONFIG_PPP_MULTILINK
140	int nxchan; /* next channel to send something on */
141	u32 nxseq; /* next sequence number to send */
142	int mrru; /* MP: max reconst. receive unit */
143	u32 nextseq; /* MP: seq no of next packet */
144	u32 minseq; /* MP: min of most recent seqnos */
145	struct sk_buff_head mrq; /* MP: receive reconstruction queue */
146	#endif /* CONFIG_PPP_MULTILINK */
147	#ifdef CONFIG_PPP_FILTER
148	struct bpf_prog *pass_filter; /* filter for packets to pass */
149	struct bpf_prog *active_filter; /* filter for pkts to reset idle */
150	#endif /* CONFIG_PPP_FILTER */
151	struct net *ppp_net; /* the net we belong to */
152	struct ppp_link_stats stats64; /* 64 bit network stats */
153	};
154
155	/*
156	* Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
157	* SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
158	* SC_MUST_COMP
159	* Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
160	* Bits in xstate: SC_COMP_RUN
161	*/
162	#define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
163	|SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
164	|SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
165
166	/*
167	* Private data structure for each channel.
168	* This includes the data structure used for multilink.
169	*/
170	struct channel {
171	struct ppp_file file; /* stuff for read/write/poll */
172	struct list_head list; /* link in all/new_channels list */
173	struct ppp_channel *chan; /* public channel data structure */
174	struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */
175	spinlock_t downl; /* protects `chan', file.xq dequeue */
176	struct ppp *ppp; /* ppp unit we're connected to */
177	struct net *chan_net; /* the net channel belongs to */
178	netns_tracker ns_tracker;
179	struct list_head clist; /* link in list of channels per unit */
180	rwlock_t upl; /* protects `ppp' and 'bridge' */
181	struct channel __rcu *bridge; /* "bridged" ppp channel */
182	#ifdef CONFIG_PPP_MULTILINK
183	u8 avail; /* flag used in multilink stuff */
184	u8 had_frag; /* >= 1 fragments have been sent */
185	u32 lastseq; /* MP: last sequence # received */
186	int speed; /* speed of the corresponding ppp channel*/
187	#endif /* CONFIG_PPP_MULTILINK */
188	};
189
190	struct ppp_config {
191	struct file *file;
192	s32 unit;
193	bool ifname_is_set;
194	};
195
196	/*
197	* SMP locking issues:
198	* Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
199	* list and the ppp.n_channels field, you need to take both locks
200	* before you modify them.
201	* The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
202	* channel.downl.
203	*/
204
205	static DEFINE_MUTEX(ppp_mutex);
206	static atomic_t ppp_unit_count = ATOMIC_INIT(0);
207	static atomic_t channel_count = ATOMIC_INIT(0);
208
209	/* per-net private data for this module */
210	static unsigned int ppp_net_id __read_mostly;
211	struct ppp_net {
212	/* units to ppp mapping */
213	struct idr units_idr;
214
215	/*
216	* all_ppp_mutex protects the units_idr mapping.
217	* It also ensures that finding a ppp unit in the units_idr
218	* map and updating its file.refcnt field is atomic.
219	*/
220	struct mutex all_ppp_mutex;
221
222	/* channels */
223	struct list_head all_channels;
224	struct list_head new_channels;
225	int last_channel_index;
226
227	/*
228	* all_channels_lock protects all_channels and
229	* last_channel_index, and the atomicity of find
230	* a channel and updating its file.refcnt field.
231	*/
232	spinlock_t all_channels_lock;
233	};
234
235	/* Get the PPP protocol number from a skb */
236	#define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
237
238	/* We limit the length of ppp->file.rq to this (arbitrary) value */
239	#define PPP_MAX_RQLEN 32
240
241	/*
242	* Maximum number of multilink fragments queued up.
243	* This has to be large enough to cope with the maximum latency of
244	* the slowest channel relative to the others. Strictly it should
245	* depend on the number of channels and their characteristics.
246	*/
247	#define PPP_MP_MAX_QLEN 128
248
249	/* Multilink header bits. */
250	#define B 0x80 /* this fragment begins a packet */
251	#define E 0x40 /* this fragment ends a packet */
252
253	/* Compare multilink sequence numbers (assumed to be 32 bits wide) */
254	#define seq_before(a, b) ((s32)((a) - (b)) < 0)
255	#define seq_after(a, b) ((s32)((a) - (b)) > 0)
256
257	/* Prototypes. */
258	static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
259	struct file *file, unsigned int cmd, unsigned long arg);
260	static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
261	static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
262	static void ppp_push(struct ppp *ppp);
263	static void ppp_channel_push(struct channel *pch);
264	static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
265	struct channel *pch);
266	static void ppp_receive_error(struct ppp *ppp);
267	static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
268	static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
269	struct sk_buff *skb);
270	#ifdef CONFIG_PPP_MULTILINK
271	static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
272	struct channel *pch);
273	static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
274	static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
275	static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
276	#endif /* CONFIG_PPP_MULTILINK */
277	static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
278	static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
279	static void ppp_ccp_closed(struct ppp *ppp);
280	static struct compressor *find_compressor(int type);
281	static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
282	static int ppp_create_interface(struct net *net, struct file *file, int *unit);
283	static void init_ppp_file(struct ppp_file *pf, int kind);
284	static void ppp_destroy_interface(struct ppp *ppp);
285	static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
286	static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
287	static int ppp_connect_channel(struct channel *pch, int unit);
288	static int ppp_disconnect_channel(struct channel *pch);
289	static void ppp_destroy_channel(struct channel *pch);
290	static int unit_get(struct idr *p, void *ptr, int min);
291	static int unit_set(struct idr *p, void *ptr, int n);
292	static void unit_put(struct idr *p, int n);
293	static void *unit_find(struct idr *p, int n);
294	static void ppp_setup(struct net_device *dev);
295
296	static const struct net_device_ops ppp_netdev_ops;
297
298	static struct class *ppp_class;
299
300	/* per net-namespace data */
301	static inline struct ppp_net *ppp_pernet(struct net *net)
302	{
303	return net_generic(net, id: ppp_net_id);
304	}
305
306	/* Translates a PPP protocol number to a NP index (NP == network protocol) */
307	static inline int proto_to_npindex(int proto)
308	{
309	switch (proto) {
310	case PPP_IP:
311	return NP_IP;
312	case PPP_IPV6:
313	return NP_IPV6;
314	case PPP_IPX:
315	return NP_IPX;
316	case PPP_AT:
317	return NP_AT;
318	case PPP_MPLS_UC:
319	return NP_MPLS_UC;
320	case PPP_MPLS_MC:
321	return NP_MPLS_MC;
322	}
323	return -EINVAL;
324	}
325
326	/* Translates an NP index into a PPP protocol number */
327	static const int npindex_to_proto[NUM_NP] = {
328	PPP_IP,
329	PPP_IPV6,
330	PPP_IPX,
331	PPP_AT,
332	PPP_MPLS_UC,
333	PPP_MPLS_MC,
334	};
335
336	/* Translates an ethertype into an NP index */
337	static inline int ethertype_to_npindex(int ethertype)
338	{
339	switch (ethertype) {
340	case ETH_P_IP:
341	return NP_IP;
342	case ETH_P_IPV6:
343	return NP_IPV6;
344	case ETH_P_IPX:
345	return NP_IPX;
346	case ETH_P_PPPTALK:
347	case ETH_P_ATALK:
348	return NP_AT;
349	case ETH_P_MPLS_UC:
350	return NP_MPLS_UC;
351	case ETH_P_MPLS_MC:
352	return NP_MPLS_MC;
353	}
354	return -1;
355	}
356
357	/* Translates an NP index into an ethertype */
358	static const int npindex_to_ethertype[NUM_NP] = {
359	ETH_P_IP,
360	ETH_P_IPV6,
361	ETH_P_IPX,
362	ETH_P_PPPTALK,
363	ETH_P_MPLS_UC,
364	ETH_P_MPLS_MC,
365	};
366
367	/*
368	* Locking shorthand.
369	*/
370	#define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
371	#define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
372	#define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
373	#define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
374	#define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
375	ppp_recv_lock(ppp); } while (0)
376	#define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
377	ppp_xmit_unlock(ppp); } while (0)
378
379	/*
380	* /dev/ppp device routines.
381	* The /dev/ppp device is used by pppd to control the ppp unit.
382	* It supports the read, write, ioctl and poll functions.
383	* Open instances of /dev/ppp can be in one of three states:
384	* unattached, attached to a ppp unit, or attached to a ppp channel.
385	*/
386	static int ppp_open(struct inode *inode, struct file *file)
387	{
388	/*
389	* This could (should?) be enforced by the permissions on /dev/ppp.
390	*/
391	if (!ns_capable(ns: file->f_cred->user_ns, CAP_NET_ADMIN))
392	return -EPERM;
393	return 0;
394	}
395
396	static int ppp_release(struct inode *unused, struct file *file)
397	{
398	struct ppp_file *pf = file->private_data;
399	struct ppp *ppp;
400
401	if (pf) {
402	file->private_data = NULL;
403	if (pf->kind == INTERFACE) {
404	ppp = PF_TO_PPP(pf);
405	rtnl_lock();
406	if (file == ppp->owner)
407	unregister_netdevice(dev: ppp->dev);
408	rtnl_unlock();
409	}
410	if (refcount_dec_and_test(r: &pf->refcnt)) {
411	switch (pf->kind) {
412	case INTERFACE:
413	ppp_destroy_interface(PF_TO_PPP(pf));
414	break;
415	case CHANNEL:
416	ppp_destroy_channel(PF_TO_CHANNEL(pf));
417	break;
418	}
419	}
420	}
421	return 0;
422	}
423
424	static ssize_t ppp_read(struct file *file, char __user *buf,
425	size_t count, loff_t *ppos)
426	{
427	struct ppp_file *pf = file->private_data;
428	DECLARE_WAITQUEUE(wait, current);
429	ssize_t ret;
430	struct sk_buff *skb = NULL;
431	struct iovec iov;
432	struct iov_iter to;
433
434	ret = count;
435
436	if (!pf)
437	return -ENXIO;
438	add_wait_queue(wq_head: &pf->rwait, wq_entry: &wait);
439	for (;;) {
440	set_current_state(TASK_INTERRUPTIBLE);
441	skb = skb_dequeue(list: &pf->rq);
442	if (skb)
443	break;
444	ret = 0;
445	if (pf->dead)
446	break;
447	if (pf->kind == INTERFACE) {
448	/*
449	* Return 0 (EOF) on an interface that has no
450	* channels connected, unless it is looping
451	* network traffic (demand mode).
452	*/
453	struct ppp *ppp = PF_TO_PPP(pf);
454
455	ppp_recv_lock(ppp);
456	if (ppp->n_channels == 0 &&
457	(ppp->flags & SC_LOOP_TRAFFIC) == 0) {
458	ppp_recv_unlock(ppp);
459	break;
460	}
461	ppp_recv_unlock(ppp);
462	}
463	ret = -EAGAIN;
464	if (file->f_flags & O_NONBLOCK)
465	break;
466	ret = -ERESTARTSYS;
467	if (signal_pending(current))
468	break;
469	schedule();
470	}
471	set_current_state(TASK_RUNNING);
472	remove_wait_queue(wq_head: &pf->rwait, wq_entry: &wait);
473
474	if (!skb)
475	goto out;
476
477	ret = -EOVERFLOW;
478	if (skb->len > count)
479	goto outf;
480	ret = -EFAULT;
481	iov.iov_base = buf;
482	iov.iov_len = count;
483	iov_iter_init(i: &to, ITER_DEST, iov: &iov, nr_segs: 1, count);
484	if (skb_copy_datagram_iter(from: skb, offset: 0, to: &to, size: skb->len))
485	goto outf;
486	ret = skb->len;
487
488	outf:
489	kfree_skb(skb);
490	out:
491	return ret;
492	}
493
494	static ssize_t ppp_write(struct file *file, const char __user *buf,
495	size_t count, loff_t *ppos)
496	{
497	struct ppp_file *pf = file->private_data;
498	struct sk_buff *skb;
499	ssize_t ret;
500
501	if (!pf)
502	return -ENXIO;
503	/* All PPP packets should start with the 2-byte protocol */
504	if (count < PPP_PROTO_LEN)
505	return -EINVAL;
506	ret = -ENOMEM;
507	skb = alloc_skb(size: count + pf->hdrlen, GFP_KERNEL);
508	if (!skb)
509	goto out;
510	skb_reserve(skb, len: pf->hdrlen);
511	ret = -EFAULT;
512	if (copy_from_user(to: skb_put(skb, len: count), from: buf, n: count)) {
513	kfree_skb(skb);
514	goto out;
515	}
516
517	switch (pf->kind) {
518	case INTERFACE:
519	ppp_xmit_process(PF_TO_PPP(pf), skb);
520	break;
521	case CHANNEL:
522	skb_queue_tail(list: &pf->xq, newsk: skb);
523	ppp_channel_push(PF_TO_CHANNEL(pf));
524	break;
525	}
526
527	ret = count;
528
529	out:
530	return ret;
531	}
532
533	/* No kernel lock - fine */
534	static __poll_t ppp_poll(struct file *file, poll_table *wait)
535	{
536	struct ppp_file *pf = file->private_data;
537	__poll_t mask;
538
539	if (!pf)
540	return 0;
541	poll_wait(filp: file, wait_address: &pf->rwait, p: wait);
542	mask = EPOLLOUT | EPOLLWRNORM;
543	if (skb_peek(list_: &pf->rq))
544	mask |= EPOLLIN | EPOLLRDNORM;
545	if (pf->dead)
546	mask |= EPOLLHUP;
547	else if (pf->kind == INTERFACE) {
548	/* see comment in ppp_read */
549	struct ppp *ppp = PF_TO_PPP(pf);
550
551	ppp_recv_lock(ppp);
552	if (ppp->n_channels == 0 &&
553	(ppp->flags & SC_LOOP_TRAFFIC) == 0)
554	mask |= EPOLLIN | EPOLLRDNORM;
555	ppp_recv_unlock(ppp);
556	}
557
558	return mask;
559	}
560
561	#ifdef CONFIG_PPP_FILTER
562	static struct bpf_prog *get_filter(struct sock_fprog *uprog)
563	{
564	struct sock_fprog_kern fprog;
565	struct bpf_prog *res = NULL;
566	int err;
567
568	if (!uprog->len)
569	return NULL;
570
571	/* uprog->len is unsigned short, so no overflow here */
572	fprog.len = uprog->len;
573	fprog.filter = memdup_user(uprog->filter,
574	uprog->len * sizeof(struct sock_filter));
575	if (IS_ERR(ptr: fprog.filter))
576	return ERR_CAST(ptr: fprog.filter);
577
578	err = bpf_prog_create(pfp: &res, fprog: &fprog);
579	kfree(objp: fprog.filter);
580
581	return err ? ERR_PTR(error: err) : res;
582	}
583
584	static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
585	{
586	struct sock_fprog uprog;
587
588	if (copy_from_user(to: &uprog, from: p, n: sizeof(struct sock_fprog)))
589	return ERR_PTR(error: -EFAULT);
590	return get_filter(uprog: &uprog);
591	}
592
593	#ifdef CONFIG_COMPAT
594	struct sock_fprog32 {
595	unsigned short len;
596	compat_caddr_t filter;
597	};
598
599	#define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32)
600	#define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32)
601
602	static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
603	{
604	struct sock_fprog32 uprog32;
605	struct sock_fprog uprog;
606
607	if (copy_from_user(to: &uprog32, from: p, n: sizeof(struct sock_fprog32)))
608	return ERR_PTR(error: -EFAULT);
609	uprog.len = uprog32.len;
610	uprog.filter = compat_ptr(uptr: uprog32.filter);
611	return get_filter(uprog: &uprog);
612	}
613	#endif
614	#endif
615
616	/* Bridge one PPP channel to another.
617	* When two channels are bridged, ppp_input on one channel is redirected to
618	* the other's ops->start_xmit handler.
619	* In order to safely bridge channels we must reject channels which are already
620	* part of a bridge instance, or which form part of an existing unit.
621	* Once successfully bridged, each channel holds a reference on the other
622	* to prevent it being freed while the bridge is extant.
623	*/
624	static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
625	{
626	write_lock_bh(&pch->upl);
627	if (pch->ppp ||
628	rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
629	write_unlock_bh(&pch->upl);
630	return -EALREADY;
631	}
632	refcount_inc(r: &pchb->file.refcnt);
633	rcu_assign_pointer(pch->bridge, pchb);
634	write_unlock_bh(&pch->upl);
635
636	write_lock_bh(&pchb->upl);
637	if (pchb->ppp ||
638	rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
639	write_unlock_bh(&pchb->upl);
640	goto err_unset;
641	}
642	refcount_inc(r: &pch->file.refcnt);
643	rcu_assign_pointer(pchb->bridge, pch);
644	write_unlock_bh(&pchb->upl);
645
646	return 0;
647
648	err_unset:
649	write_lock_bh(&pch->upl);
650	/* Re-read pch->bridge with upl held in case it was modified concurrently */
651	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
652	RCU_INIT_POINTER(pch->bridge, NULL);
653	write_unlock_bh(&pch->upl);
654	synchronize_rcu();
655
656	if (pchb)
657	if (refcount_dec_and_test(r: &pchb->file.refcnt))
658	ppp_destroy_channel(pch: pchb);
659
660	return -EALREADY;
661	}
662
663	static int ppp_unbridge_channels(struct channel *pch)
664	{
665	struct channel *pchb, *pchbb;
666
667	write_lock_bh(&pch->upl);
668	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
669	if (!pchb) {
670	write_unlock_bh(&pch->upl);
671	return -EINVAL;
672	}
673	RCU_INIT_POINTER(pch->bridge, NULL);
674	write_unlock_bh(&pch->upl);
675
676	/* Only modify pchb if phcb->bridge points back to pch.
677	* If not, it implies that there has been a race unbridging (and possibly
678	* even rebridging) pchb. We should leave pchb alone to avoid either a
679	* refcount underflow, or breaking another established bridge instance.
680	*/
681	write_lock_bh(&pchb->upl);
682	pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
683	if (pchbb == pch)
684	RCU_INIT_POINTER(pchb->bridge, NULL);
685	write_unlock_bh(&pchb->upl);
686
687	synchronize_rcu();
688
689	if (pchbb == pch)
690	if (refcount_dec_and_test(r: &pch->file.refcnt))
691	ppp_destroy_channel(pch);
692
693	if (refcount_dec_and_test(r: &pchb->file.refcnt))
694	ppp_destroy_channel(pch: pchb);
695
696	return 0;
697	}
698
699	static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
700	{
701	struct ppp_file *pf;
702	struct ppp *ppp;
703	int err = -EFAULT, val, val2, i;
704	struct ppp_idle32 idle32;
705	struct ppp_idle64 idle64;
706	struct npioctl npi;
707	int unit, cflags;
708	struct slcompress *vj;
709	void __user *argp = (void __user *)arg;
710	int __user *p = argp;
711
712	mutex_lock(&ppp_mutex);
713
714	pf = file->private_data;
715	if (!pf) {
716	err = ppp_unattached_ioctl(current->nsproxy->net_ns,
717	pf, file, cmd, arg);
718	goto out;
719	}
720
721	if (cmd == PPPIOCDETACH) {
722	/*
723	* PPPIOCDETACH is no longer supported as it was heavily broken,
724	* and is only known to have been used by pppd older than
725	* ppp-2.4.2 (released November 2003).
726	*/
727	pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
728	current->comm, current->pid);
729	err = -EINVAL;
730	goto out;
731	}
732
733	if (pf->kind == CHANNEL) {
734	struct channel *pch, *pchb;
735	struct ppp_channel *chan;
736	struct ppp_net *pn;
737
738	pch = PF_TO_CHANNEL(pf);
739
740	switch (cmd) {
741	case PPPIOCCONNECT:
742	if (get_user(unit, p))
743	break;
744	err = ppp_connect_channel(pch, unit);
745	break;
746
747	case PPPIOCDISCONN:
748	err = ppp_disconnect_channel(pch);
749	break;
750
751	case PPPIOCBRIDGECHAN:
752	if (get_user(unit, p))
753	break;
754	err = -ENXIO;
755	pn = ppp_pernet(current->nsproxy->net_ns);
756	spin_lock_bh(lock: &pn->all_channels_lock);
757	pchb = ppp_find_channel(pn, unit);
758	/* Hold a reference to prevent pchb being freed while
759	* we establish the bridge.
760	*/
761	if (pchb)
762	refcount_inc(r: &pchb->file.refcnt);
763	spin_unlock_bh(lock: &pn->all_channels_lock);
764	if (!pchb)
765	break;
766	err = ppp_bridge_channels(pch, pchb);
767	/* Drop earlier refcount now bridge establishment is complete */
768	if (refcount_dec_and_test(r: &pchb->file.refcnt))
769	ppp_destroy_channel(pch: pchb);
770	break;
771
772	case PPPIOCUNBRIDGECHAN:
773	err = ppp_unbridge_channels(pch);
774	break;
775
776	default:
777	down_read(sem: &pch->chan_sem);
778	chan = pch->chan;
779	err = -ENOTTY;
780	if (chan && chan->ops->ioctl)
781	err = chan->ops->ioctl(chan, cmd, arg);
782	up_read(sem: &pch->chan_sem);
783	}
784	goto out;
785	}
786
787	if (pf->kind != INTERFACE) {
788	/* can't happen */
789	pr_err("PPP: not interface or channel??\n");
790	err = -EINVAL;
791	goto out;
792	}
793
794	ppp = PF_TO_PPP(pf);
795	switch (cmd) {
796	case PPPIOCSMRU:
797	if (get_user(val, p))
798	break;
799	ppp->mru = val;
800	err = 0;
801	break;
802
803	case PPPIOCSFLAGS:
804	if (get_user(val, p))
805	break;
806	ppp_lock(ppp);
807	cflags = ppp->flags & ~val;
808	#ifdef CONFIG_PPP_MULTILINK
809	if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
810	ppp->nextseq = 0;
811	#endif
812	ppp->flags = val & SC_FLAG_BITS;
813	ppp_unlock(ppp);
814	if (cflags & SC_CCP_OPEN)
815	ppp_ccp_closed(ppp);
816	err = 0;
817	break;
818
819	case PPPIOCGFLAGS:
820	val = ppp->flags | ppp->xstate | ppp->rstate;
821	if (put_user(val, p))
822	break;
823	err = 0;
824	break;
825
826	case PPPIOCSCOMPRESS:
827	{
828	struct ppp_option_data data;
829	if (copy_from_user(to: &data, from: argp, n: sizeof(data)))
830	err = -EFAULT;
831	else
832	err = ppp_set_compress(ppp, data: &data);
833	break;
834	}
835	case PPPIOCGUNIT:
836	if (put_user(ppp->file.index, p))
837	break;
838	err = 0;
839	break;
840
841	case PPPIOCSDEBUG:
842	if (get_user(val, p))
843	break;
844	ppp->debug = val;
845	err = 0;
846	break;
847
848	case PPPIOCGDEBUG:
849	if (put_user(ppp->debug, p))
850	break;
851	err = 0;
852	break;
853
854	case PPPIOCGIDLE32:
855	idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
856	idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
857	if (copy_to_user(to: argp, from: &idle32, n: sizeof(idle32)))
858	break;
859	err = 0;
860	break;
861
862	case PPPIOCGIDLE64:
863	idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
864	idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
865	if (copy_to_user(to: argp, from: &idle64, n: sizeof(idle64)))
866	break;
867	err = 0;
868	break;
869
870	case PPPIOCSMAXCID:
871	if (get_user(val, p))
872	break;
873	val2 = 15;
874	if ((val >> 16) != 0) {
875	val2 = val >> 16;
876	val &= 0xffff;
877	}
878	vj = slhc_init(rslots: val2+1, tslots: val+1);
879	if (IS_ERR(ptr: vj)) {
880	err = PTR_ERR(ptr: vj);
881	break;
882	}
883	ppp_lock(ppp);
884	if (ppp->vj)
885	slhc_free(comp: ppp->vj);
886	ppp->vj = vj;
887	ppp_unlock(ppp);
888	err = 0;
889	break;
890
891	case PPPIOCGNPMODE:
892	case PPPIOCSNPMODE:
893	if (copy_from_user(to: &npi, from: argp, n: sizeof(npi)))
894	break;
895	err = proto_to_npindex(proto: npi.protocol);
896	if (err < 0)
897	break;
898	i = err;
899	if (cmd == PPPIOCGNPMODE) {
900	err = -EFAULT;
901	npi.mode = ppp->npmode[i];
902	if (copy_to_user(to: argp, from: &npi, n: sizeof(npi)))
903	break;
904	} else {
905	ppp->npmode[i] = npi.mode;
906	/* we may be able to transmit more packets now (??) */
907	netif_wake_queue(dev: ppp->dev);
908	}
909	err = 0;
910	break;
911
912	#ifdef CONFIG_PPP_FILTER
913	case PPPIOCSPASS:
914	case PPPIOCSACTIVE:
915	{
916	struct bpf_prog *filter = ppp_get_filter(p: argp);
917	struct bpf_prog **which;
918
919	if (IS_ERR(ptr: filter)) {
920	err = PTR_ERR(ptr: filter);
921	break;
922	}
923	if (cmd == PPPIOCSPASS)
924	which = &ppp->pass_filter;
925	else
926	which = &ppp->active_filter;
927	ppp_lock(ppp);
928	if (*which)
929	bpf_prog_destroy(fp: *which);
930	*which = filter;
931	ppp_unlock(ppp);
932	err = 0;
933	break;
934	}
935	#endif /* CONFIG_PPP_FILTER */
936
937	#ifdef CONFIG_PPP_MULTILINK
938	case PPPIOCSMRRU:
939	if (get_user(val, p))
940	break;
941	ppp_recv_lock(ppp);
942	ppp->mrru = val;
943	ppp_recv_unlock(ppp);
944	err = 0;
945	break;
946	#endif /* CONFIG_PPP_MULTILINK */
947
948	default:
949	err = -ENOTTY;
950	}
951
952	out:
953	mutex_unlock(lock: &ppp_mutex);
954
955	return err;
956	}
957
958	#ifdef CONFIG_COMPAT
959	struct ppp_option_data32 {
960	compat_uptr_t ptr;
961	u32 length;
962	compat_int_t transmit;
963	};
964	#define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)
965
966	static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
967	{
968	struct ppp_file *pf;
969	int err = -ENOIOCTLCMD;
970	void __user *argp = (void __user *)arg;
971
972	mutex_lock(&ppp_mutex);
973
974	pf = file->private_data;
975	if (pf && pf->kind == INTERFACE) {
976	struct ppp *ppp = PF_TO_PPP(pf);
977	switch (cmd) {
978	#ifdef CONFIG_PPP_FILTER
979	case PPPIOCSPASS32:
980	case PPPIOCSACTIVE32:
981	{
982	struct bpf_prog *filter = compat_ppp_get_filter(p: argp);
983	struct bpf_prog **which;
984
985	if (IS_ERR(ptr: filter)) {
986	err = PTR_ERR(ptr: filter);
987	break;
988	}
989	if (cmd == PPPIOCSPASS32)
990	which = &ppp->pass_filter;
991	else
992	which = &ppp->active_filter;
993	ppp_lock(ppp);
994	if (*which)
995	bpf_prog_destroy(fp: *which);
996	*which = filter;
997	ppp_unlock(ppp);
998	err = 0;
999	break;
1000	}
1001	#endif /* CONFIG_PPP_FILTER */
1002	case PPPIOCSCOMPRESS32:
1003	{
1004	struct ppp_option_data32 data32;
1005	if (copy_from_user(to: &data32, from: argp, n: sizeof(data32))) {
1006	err = -EFAULT;
1007	} else {
1008	struct ppp_option_data data = {
1009	.ptr = compat_ptr(uptr: data32.ptr),
1010	.length = data32.length,
1011	.transmit = data32.transmit
1012	};
1013	err = ppp_set_compress(ppp, data: &data);
1014	}
1015	break;
1016	}
1017	}
1018	}
1019	mutex_unlock(lock: &ppp_mutex);
1020
1021	/* all other commands have compatible arguments */
1022	if (err == -ENOIOCTLCMD)
1023	err = ppp_ioctl(file, cmd, arg: (unsigned long)compat_ptr(uptr: arg));
1024
1025	return err;
1026	}
1027	#endif
1028
1029	static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1030	struct file *file, unsigned int cmd, unsigned long arg)
1031	{
1032	int unit, err = -EFAULT;
1033	struct ppp *ppp;
1034	struct channel *chan;
1035	struct ppp_net *pn;
1036	int __user *p = (int __user *)arg;
1037
1038	switch (cmd) {
1039	case PPPIOCNEWUNIT:
1040	/* Create a new ppp unit */
1041	if (get_user(unit, p))
1042	break;
1043	err = ppp_create_interface(net, file, unit: &unit);
1044	if (err < 0)
1045	break;
1046
1047	err = -EFAULT;
1048	if (put_user(unit, p))
1049	break;
1050	err = 0;
1051	break;
1052
1053	case PPPIOCATTACH:
1054	/* Attach to an existing ppp unit */
1055	if (get_user(unit, p))
1056	break;
1057	err = -ENXIO;
1058	pn = ppp_pernet(net);
1059	mutex_lock(&pn->all_ppp_mutex);
1060	ppp = ppp_find_unit(pn, unit);
1061	if (ppp) {
1062	refcount_inc(r: &ppp->file.refcnt);
1063	file->private_data = &ppp->file;
1064	err = 0;
1065	}
1066	mutex_unlock(lock: &pn->all_ppp_mutex);
1067	break;
1068
1069	case PPPIOCATTCHAN:
1070	if (get_user(unit, p))
1071	break;
1072	err = -ENXIO;
1073	pn = ppp_pernet(net);
1074	spin_lock_bh(lock: &pn->all_channels_lock);
1075	chan = ppp_find_channel(pn, unit);
1076	if (chan) {
1077	refcount_inc(r: &chan->file.refcnt);
1078	file->private_data = &chan->file;
1079	err = 0;
1080	}
1081	spin_unlock_bh(lock: &pn->all_channels_lock);
1082	break;
1083
1084	default:
1085	err = -ENOTTY;
1086	}
1087
1088	return err;
1089	}
1090
1091	static const struct file_operations ppp_device_fops = {
1092	.owner = THIS_MODULE,
1093	.read = ppp_read,
1094	.write = ppp_write,
1095	.poll = ppp_poll,
1096	.unlocked_ioctl = ppp_ioctl,
1097	#ifdef CONFIG_COMPAT
1098	.compat_ioctl = ppp_compat_ioctl,
1099	#endif
1100	.open = ppp_open,
1101	.release = ppp_release,
1102	.llseek = noop_llseek,
1103	};
1104
1105	static __net_init int ppp_init_net(struct net *net)
1106	{
1107	struct ppp_net *pn = net_generic(net, id: ppp_net_id);
1108
1109	idr_init(idr: &pn->units_idr);
1110	mutex_init(&pn->all_ppp_mutex);
1111
1112	INIT_LIST_HEAD(list: &pn->all_channels);
1113	INIT_LIST_HEAD(list: &pn->new_channels);
1114
1115	spin_lock_init(&pn->all_channels_lock);
1116
1117	return 0;
1118	}
1119
1120	static __net_exit void ppp_exit_net(struct net *net)
1121	{
1122	struct ppp_net *pn = net_generic(net, id: ppp_net_id);
1123	struct net_device *dev;
1124	struct net_device *aux;
1125	struct ppp *ppp;
1126	LIST_HEAD(list);
1127	int id;
1128
1129	rtnl_lock();
1130	for_each_netdev_safe(net, dev, aux) {
1131	if (dev->netdev_ops == &ppp_netdev_ops)
1132	unregister_netdevice_queue(dev, head: &list);
1133	}
1134
1135	idr_for_each_entry(&pn->units_idr, ppp, id)
1136	/* Skip devices already unregistered by previous loop */
1137	if (!net_eq(net1: dev_net(dev: ppp->dev), net2: net))
1138	unregister_netdevice_queue(dev: ppp->dev, head: &list);
1139
1140	unregister_netdevice_many(head: &list);
1141	rtnl_unlock();
1142
1143	mutex_destroy(lock: &pn->all_ppp_mutex);
1144	idr_destroy(&pn->units_idr);
1145	WARN_ON_ONCE(!list_empty(&pn->all_channels));
1146	WARN_ON_ONCE(!list_empty(&pn->new_channels));
1147	}
1148
1149	static struct pernet_operations ppp_net_ops = {
1150	.init = ppp_init_net,
1151	.exit = ppp_exit_net,
1152	.id = &ppp_net_id,
1153	.size = sizeof(struct ppp_net),
1154	};
1155
1156	static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1157	{
1158	struct ppp_net *pn = ppp_pernet(net: ppp->ppp_net);
1159	int ret;
1160
1161	mutex_lock(&pn->all_ppp_mutex);
1162
1163	if (unit < 0) {
1164	ret = unit_get(p: &pn->units_idr, ptr: ppp, min: 0);
1165	if (ret < 0)
1166	goto err;
1167	if (!ifname_is_set) {
1168	while (1) {
1169	snprintf(buf: ppp->dev->name, IFNAMSIZ, fmt: "ppp%i", ret);
1170	if (!netdev_name_in_use(net: ppp->ppp_net, name: ppp->dev->name))
1171	break;
1172	unit_put(p: &pn->units_idr, n: ret);
1173	ret = unit_get(p: &pn->units_idr, ptr: ppp, min: ret + 1);
1174	if (ret < 0)
1175	goto err;
1176	}
1177	}
1178	} else {
1179	/* Caller asked for a specific unit number. Fail with -EEXIST
1180	* if unavailable. For backward compatibility, return -EEXIST
1181	* too if idr allocation fails; this makes pppd retry without
1182	* requesting a specific unit number.
1183	*/
1184	if (unit_find(p: &pn->units_idr, n: unit)) {
1185	ret = -EEXIST;
1186	goto err;
1187	}
1188	ret = unit_set(p: &pn->units_idr, ptr: ppp, n: unit);
1189	if (ret < 0) {
1190	/* Rewrite error for backward compatibility */
1191	ret = -EEXIST;
1192	goto err;
1193	}
1194	}
1195	ppp->file.index = ret;
1196
1197	if (!ifname_is_set)
1198	snprintf(buf: ppp->dev->name, IFNAMSIZ, fmt: "ppp%i", ppp->file.index);
1199
1200	mutex_unlock(lock: &pn->all_ppp_mutex);
1201
1202	ret = register_netdevice(dev: ppp->dev);
1203	if (ret < 0)
1204	goto err_unit;
1205
1206	atomic_inc(v: &ppp_unit_count);
1207
1208	return 0;
1209
1210	err_unit:
1211	mutex_lock(&pn->all_ppp_mutex);
1212	unit_put(p: &pn->units_idr, n: ppp->file.index);
1213	err:
1214	mutex_unlock(lock: &pn->all_ppp_mutex);
1215
1216	return ret;
1217	}
1218
1219	static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1220	const struct ppp_config *conf)
1221	{
1222	struct ppp *ppp = netdev_priv(dev);
1223	int indx;
1224	int err;
1225	int cpu;
1226
1227	ppp->dev = dev;
1228	ppp->ppp_net = src_net;
1229	ppp->mru = PPP_MRU;
1230	ppp->owner = conf->file;
1231
1232	init_ppp_file(pf: &ppp->file, kind: INTERFACE);
1233	ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1234
1235	for (indx = 0; indx < NUM_NP; ++indx)
1236	ppp->npmode[indx] = NPMODE_PASS;
1237	INIT_LIST_HEAD(list: &ppp->channels);
1238	spin_lock_init(&ppp->rlock);
1239	spin_lock_init(&ppp->wlock);
1240
1241	ppp->xmit_recursion = alloc_percpu(int);
1242	if (!ppp->xmit_recursion) {
1243	err = -ENOMEM;
1244	goto err1;
1245	}
1246	for_each_possible_cpu(cpu)
1247	(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
1248
1249	#ifdef CONFIG_PPP_MULTILINK
1250	ppp->minseq = -1;
1251	skb_queue_head_init(list: &ppp->mrq);
1252	#endif /* CONFIG_PPP_MULTILINK */
1253	#ifdef CONFIG_PPP_FILTER
1254	ppp->pass_filter = NULL;
1255	ppp->active_filter = NULL;
1256	#endif /* CONFIG_PPP_FILTER */
1257
1258	err = ppp_unit_register(ppp, unit: conf->unit, ifname_is_set: conf->ifname_is_set);
1259	if (err < 0)
1260	goto err2;
1261
1262	conf->file->private_data = &ppp->file;
1263
1264	return 0;
1265	err2:
1266	free_percpu(pdata: ppp->xmit_recursion);
1267	err1:
1268	return err;
1269	}
1270
1271	static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1272	[IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
1273	};
1274
1275	static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1276	struct netlink_ext_ack *extack)
1277	{
1278	if (!data)
1279	return -EINVAL;
1280
1281	if (!data[IFLA_PPP_DEV_FD])
1282	return -EINVAL;
1283	if (nla_get_s32(nla: data[IFLA_PPP_DEV_FD]) < 0)
1284	return -EBADF;
1285
1286	return 0;
1287	}
1288
1289	static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
1290	struct nlattr *tb[], struct nlattr *data[],
1291	struct netlink_ext_ack *extack)
1292	{
1293	struct ppp_config conf = {
1294	.unit = -1,
1295	.ifname_is_set = true,
1296	};
1297	struct file *file;
1298	int err;
1299
1300	file = fget(fd: nla_get_s32(nla: data[IFLA_PPP_DEV_FD]));
1301	if (!file)
1302	return -EBADF;
1303
1304	/* rtnl_lock is already held here, but ppp_create_interface() locks
1305	* ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1306	* possible deadlock due to lock order inversion, at the cost of
1307	* pushing the problem back to userspace.
1308	*/
1309	if (!mutex_trylock(lock: &ppp_mutex)) {
1310	err = -EBUSY;
1311	goto out;
1312	}
1313
1314	if (file->f_op != &ppp_device_fops || file->private_data) {
1315	err = -EBADF;
1316	goto out_unlock;
1317	}
1318
1319	conf.file = file;
1320
1321	/* Don't use device name generated by the rtnetlink layer when ifname
1322	* isn't specified. Let ppp_dev_configure() set the device name using
1323	* the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1324	* userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1325	*/
1326	if (!tb[IFLA_IFNAME] || !nla_len(nla: tb[IFLA_IFNAME]) || !*(char *)nla_data(nla: tb[IFLA_IFNAME]))
1327	conf.ifname_is_set = false;
1328
1329	err = ppp_dev_configure(src_net, dev, conf: &conf);
1330
1331	out_unlock:
1332	mutex_unlock(lock: &ppp_mutex);
1333	out:
1334	fput(file);
1335
1336	return err;
1337	}
1338
1339	static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1340	{
1341	unregister_netdevice_queue(dev, head);
1342	}
1343
1344	static size_t ppp_nl_get_size(const struct net_device *dev)
1345	{
1346	return 0;
1347	}
1348
1349	static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1350	{
1351	return 0;
1352	}
1353
1354	static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1355	{
1356	struct ppp *ppp = netdev_priv(dev);
1357
1358	return ppp->ppp_net;
1359	}
1360
1361	static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1362	.kind = "ppp",
1363	.maxtype = IFLA_PPP_MAX,
1364	.policy = ppp_nl_policy,
1365	.priv_size = sizeof(struct ppp),
1366	.setup = ppp_setup,
1367	.validate = ppp_nl_validate,
1368	.newlink = ppp_nl_newlink,
1369	.dellink = ppp_nl_dellink,
1370	.get_size = ppp_nl_get_size,
1371	.fill_info = ppp_nl_fill_info,
1372	.get_link_net = ppp_nl_get_link_net,
1373	};
1374
1375	#define PPP_MAJOR 108
1376
1377	/* Called at boot time if ppp is compiled into the kernel,
1378	or at module load time (from init_module) if compiled as a module. */
1379	static int __init ppp_init(void)
1380	{
1381	int err;
1382
1383	pr_info("PPP generic driver version " PPP_VERSION "\n");
1384
1385	err = register_pernet_device(&ppp_net_ops);
1386	if (err) {
1387	pr_err("failed to register PPP pernet device (%d)\n", err);
1388	goto out;
1389	}
1390
1391	err = register_chrdev(PPP_MAJOR, name: "ppp", fops: &ppp_device_fops);
1392	if (err) {
1393	pr_err("failed to register PPP device (%d)\n", err);
1394	goto out_net;
1395	}
1396
1397	ppp_class = class_create(name: "ppp");
1398	if (IS_ERR(ptr: ppp_class)) {
1399	err = PTR_ERR(ptr: ppp_class);
1400	goto out_chrdev;
1401	}
1402
1403	err = rtnl_link_register(ops: &ppp_link_ops);
1404	if (err) {
1405	pr_err("failed to register rtnetlink PPP handler\n");
1406	goto out_class;
1407	}
1408
1409	/* not a big deal if we fail here :-) */
1410	device_create(cls: ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, fmt: "ppp");
1411
1412	return 0;
1413
1414	out_class:
1415	class_destroy(cls: ppp_class);
1416	out_chrdev:
1417	unregister_chrdev(PPP_MAJOR, name: "ppp");
1418	out_net:
1419	unregister_pernet_device(&ppp_net_ops);
1420	out:
1421	return err;
1422	}
1423
1424	/*
1425	* Network interface unit routines.
1426	*/
1427	static netdev_tx_t
1428	ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1429	{
1430	struct ppp *ppp = netdev_priv(dev);
1431	int npi, proto;
1432	unsigned char *pp;
1433
1434	npi = ethertype_to_npindex(ntohs(skb->protocol));
1435	if (npi < 0)
1436	goto outf;
1437
1438	/* Drop, accept or reject the packet */
1439	switch (ppp->npmode[npi]) {
1440	case NPMODE_PASS:
1441	break;
1442	case NPMODE_QUEUE:
1443	/* it would be nice to have a way to tell the network
1444	system to queue this one up for later. */
1445	goto outf;
1446	case NPMODE_DROP:
1447	case NPMODE_ERROR:
1448	goto outf;
1449	}
1450
1451	/* Put the 2-byte PPP protocol number on the front,
1452	making sure there is room for the address and control fields. */
1453	if (skb_cow_head(skb, PPP_HDRLEN))
1454	goto outf;
1455
1456	pp = skb_push(skb, len: 2);
1457	proto = npindex_to_proto[npi];
1458	put_unaligned_be16(val: proto, p: pp);
1459
1460	skb_scrub_packet(skb, xnet: !net_eq(net1: ppp->ppp_net, net2: dev_net(dev)));
1461	ppp_xmit_process(ppp, skb);
1462
1463	return NETDEV_TX_OK;
1464
1465	outf:
1466	kfree_skb(skb);
1467	++dev->stats.tx_dropped;
1468	return NETDEV_TX_OK;
1469	}
1470
1471	static int
1472	ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1473	void __user *addr, int cmd)
1474	{
1475	struct ppp *ppp = netdev_priv(dev);
1476	int err = -EFAULT;
1477	struct ppp_stats stats;
1478	struct ppp_comp_stats cstats;
1479	char *vers;
1480
1481	switch (cmd) {
1482	case SIOCGPPPSTATS:
1483	ppp_get_stats(ppp, st: &stats);
1484	if (copy_to_user(to: addr, from: &stats, n: sizeof(stats)))
1485	break;
1486	err = 0;
1487	break;
1488
1489	case SIOCGPPPCSTATS:
1490	memset(&cstats, 0, sizeof(cstats));
1491	if (ppp->xc_state)
1492	ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1493	if (ppp->rc_state)
1494	ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1495	if (copy_to_user(to: addr, from: &cstats, n: sizeof(cstats)))
1496	break;
1497	err = 0;
1498	break;
1499
1500	case SIOCGPPPVER:
1501	vers = PPP_VERSION;
1502	if (copy_to_user(to: addr, from: vers, strlen(vers) + 1))
1503	break;
1504	err = 0;
1505	break;
1506
1507	default:
1508	err = -EINVAL;
1509	}
1510
1511	return err;
1512	}
1513
1514	static void
1515	ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1516	{
1517	struct ppp *ppp = netdev_priv(dev);
1518
1519	ppp_recv_lock(ppp);
1520	stats64->rx_packets = ppp->stats64.rx_packets;
1521	stats64->rx_bytes = ppp->stats64.rx_bytes;
1522	ppp_recv_unlock(ppp);
1523
1524	ppp_xmit_lock(ppp);
1525	stats64->tx_packets = ppp->stats64.tx_packets;
1526	stats64->tx_bytes = ppp->stats64.tx_bytes;
1527	ppp_xmit_unlock(ppp);
1528
1529	stats64->rx_errors = dev->stats.rx_errors;
1530	stats64->tx_errors = dev->stats.tx_errors;
1531	stats64->rx_dropped = dev->stats.rx_dropped;
1532	stats64->tx_dropped = dev->stats.tx_dropped;
1533	stats64->rx_length_errors = dev->stats.rx_length_errors;
1534	}
1535
1536	static int ppp_dev_init(struct net_device *dev)
1537	{
1538	struct ppp *ppp;
1539
1540	netdev_lockdep_set_classes(dev);
1541
1542	ppp = netdev_priv(dev);
1543	/* Let the netdevice take a reference on the ppp file. This ensures
1544	* that ppp_destroy_interface() won't run before the device gets
1545	* unregistered.
1546	*/
1547	refcount_inc(r: &ppp->file.refcnt);
1548
1549	return 0;
1550	}
1551
1552	static void ppp_dev_uninit(struct net_device *dev)
1553	{
1554	struct ppp *ppp = netdev_priv(dev);
1555	struct ppp_net *pn = ppp_pernet(net: ppp->ppp_net);
1556
1557	ppp_lock(ppp);
1558	ppp->closing = 1;
1559	ppp_unlock(ppp);
1560
1561	mutex_lock(&pn->all_ppp_mutex);
1562	unit_put(p: &pn->units_idr, n: ppp->file.index);
1563	mutex_unlock(lock: &pn->all_ppp_mutex);
1564
1565	ppp->owner = NULL;
1566
1567	ppp->file.dead = 1;
1568	wake_up_interruptible(&ppp->file.rwait);
1569	}
1570
1571	static void ppp_dev_priv_destructor(struct net_device *dev)
1572	{
1573	struct ppp *ppp;
1574
1575	ppp = netdev_priv(dev);
1576	if (refcount_dec_and_test(r: &ppp->file.refcnt))
1577	ppp_destroy_interface(ppp);
1578	}
1579
1580	static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1581	struct net_device_path *path)
1582	{
1583	struct ppp *ppp = netdev_priv(dev: ctx->dev);
1584	struct ppp_channel *chan;
1585	struct channel *pch;
1586
1587	if (ppp->flags & SC_MULTILINK)
1588	return -EOPNOTSUPP;
1589
1590	if (list_empty(head: &ppp->channels))
1591	return -ENODEV;
1592
1593	pch = list_first_entry(&ppp->channels, struct channel, clist);
1594	chan = pch->chan;
1595	if (!chan->ops->fill_forward_path)
1596	return -EOPNOTSUPP;
1597
1598	return chan->ops->fill_forward_path(ctx, path, chan);
1599	}
1600
1601	static const struct net_device_ops ppp_netdev_ops = {
1602	.ndo_init = ppp_dev_init,
1603	.ndo_uninit = ppp_dev_uninit,
1604	.ndo_start_xmit = ppp_start_xmit,
1605	.ndo_siocdevprivate = ppp_net_siocdevprivate,
1606	.ndo_get_stats64 = ppp_get_stats64,
1607	.ndo_fill_forward_path = ppp_fill_forward_path,
1608	};
1609
1610	static struct device_type ppp_type = {
1611	.name = "ppp",
1612	};
1613
1614	static void ppp_setup(struct net_device *dev)
1615	{
1616	dev->netdev_ops = &ppp_netdev_ops;
1617	SET_NETDEV_DEVTYPE(dev, &ppp_type);
1618
1619	dev->features |= NETIF_F_LLTX;
1620
1621	dev->hard_header_len = PPP_HDRLEN;
1622	dev->mtu = PPP_MRU;
1623	dev->addr_len = 0;
1624	dev->tx_queue_len = 3;
1625	dev->type = ARPHRD_PPP;
1626	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1627	dev->priv_destructor = ppp_dev_priv_destructor;
1628	netif_keep_dst(dev);
1629	}
1630
1631	/*
1632	* Transmit-side routines.
1633	*/
1634
1635	/* Called to do any work queued up on the transmit side that can now be done */
1636	static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1637	{
1638	ppp_xmit_lock(ppp);
1639	if (!ppp->closing) {
1640	ppp_push(ppp);
1641
1642	if (skb)
1643	skb_queue_tail(list: &ppp->file.xq, newsk: skb);
1644	while (!ppp->xmit_pending &&
1645	(skb = skb_dequeue(list: &ppp->file.xq)))
1646	ppp_send_frame(ppp, skb);
1647	/* If there's no work left to do, tell the core net
1648	code that we can accept some more. */
1649	if (!ppp->xmit_pending && !skb_peek(list_: &ppp->file.xq))
1650	netif_wake_queue(dev: ppp->dev);
1651	else
1652	netif_stop_queue(dev: ppp->dev);
1653	} else {
1654	kfree_skb(skb);
1655	}
1656	ppp_xmit_unlock(ppp);
1657	}
1658
1659	static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1660	{
1661	local_bh_disable();
1662
1663	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
1664	goto err;
1665
1666	(*this_cpu_ptr(ppp->xmit_recursion))++;
1667	__ppp_xmit_process(ppp, skb);
1668	(*this_cpu_ptr(ppp->xmit_recursion))--;
1669
1670	local_bh_enable();
1671
1672	return;
1673
1674	err:
1675	local_bh_enable();
1676
1677	kfree_skb(skb);
1678
1679	if (net_ratelimit())
1680	netdev_err(dev: ppp->dev, format: "recursion detected\n");
1681	}
1682
1683	static inline struct sk_buff *
1684	pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1685	{
1686	struct sk_buff *new_skb;
1687	int len;
1688	int new_skb_size = ppp->dev->mtu +
1689	ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1690	int compressor_skb_size = ppp->dev->mtu +
1691	ppp->xcomp->comp_extra + PPP_HDRLEN;
1692	new_skb = alloc_skb(size: new_skb_size, GFP_ATOMIC);
1693	if (!new_skb) {
1694	if (net_ratelimit())
1695	netdev_err(dev: ppp->dev, format: "PPP: no memory (comp pkt)\n");
1696	return NULL;
1697	}
1698	if (ppp->dev->hard_header_len > PPP_HDRLEN)
1699	skb_reserve(skb: new_skb,
1700	len: ppp->dev->hard_header_len - PPP_HDRLEN);
1701
1702	/* compressor still expects A/C bytes in hdr */
1703	len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1704	new_skb->data, skb->len + 2,
1705	compressor_skb_size);
1706	if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1707	consume_skb(skb);
1708	skb = new_skb;
1709	skb_put(skb, len);
1710	skb_pull(skb, len: 2); /* pull off A/C bytes */
1711	} else if (len == 0) {
1712	/* didn't compress, or CCP not up yet */
1713	consume_skb(skb: new_skb);
1714	new_skb = skb;
1715	} else {
1716	/*
1717	* (len < 0)
1718	* MPPE requires that we do not send unencrypted
1719	* frames. The compressor will return -1 if we
1720	* should drop the frame. We cannot simply test
1721	* the compress_proto because MPPE and MPPC share
1722	* the same number.
1723	*/
1724	if (net_ratelimit())
1725	netdev_err(dev: ppp->dev, format: "ppp: compressor dropped pkt\n");
1726	kfree_skb(skb);
1727	consume_skb(skb: new_skb);
1728	new_skb = NULL;
1729	}
1730	return new_skb;
1731	}
1732
1733	/*
1734	* Compress and send a frame.
1735	* The caller should have locked the xmit path,
1736	* and xmit_pending should be 0.
1737	*/
1738	static void
1739	ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1740	{
1741	int proto = PPP_PROTO(skb);
1742	struct sk_buff *new_skb;
1743	int len;
1744	unsigned char *cp;
1745
1746	skb->dev = ppp->dev;
1747
1748	if (proto < 0x8000) {
1749	#ifdef CONFIG_PPP_FILTER
1750	/* check if we should pass this packet */
1751	/* the filter instructions are constructed assuming
1752	a four-byte PPP header on each packet */
1753	*(u8 *)skb_push(skb, len: 2) = 1;
1754	if (ppp->pass_filter &&
1755	bpf_prog_run(prog: ppp->pass_filter, ctx: skb) == 0) {
1756	if (ppp->debug & 1)
1757	netdev_printk(KERN_DEBUG, dev: ppp->dev,
1758	format: "PPP: outbound frame "
1759	"not passed\n");
1760	kfree_skb(skb);
1761	return;
1762	}
1763	/* if this packet passes the active filter, record the time */
1764	if (!(ppp->active_filter &&
1765	bpf_prog_run(prog: ppp->active_filter, ctx: skb) == 0))
1766	ppp->last_xmit = jiffies;
1767	skb_pull(skb, len: 2);
1768	#else
1769	/* for data packets, record the time */
1770	ppp->last_xmit = jiffies;
1771	#endif /* CONFIG_PPP_FILTER */
1772	}
1773
1774	++ppp->stats64.tx_packets;
1775	ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN;
1776
1777	switch (proto) {
1778	case PPP_IP:
1779	if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1780	break;
1781	/* try to do VJ TCP header compression */
1782	new_skb = alloc_skb(size: skb->len + ppp->dev->hard_header_len - 2,
1783	GFP_ATOMIC);
1784	if (!new_skb) {
1785	netdev_err(dev: ppp->dev, format: "PPP: no memory (VJ comp pkt)\n");
1786	goto drop;
1787	}
1788	skb_reserve(skb: new_skb, len: ppp->dev->hard_header_len - 2);
1789	cp = skb->data + 2;
1790	len = slhc_compress(comp: ppp->vj, icp: cp, isize: skb->len - 2,
1791	ocp: new_skb->data + 2, cpp: &cp,
1792	compress_cid: !(ppp->flags & SC_NO_TCP_CCID));
1793	if (cp == skb->data + 2) {
1794	/* didn't compress */
1795	consume_skb(skb: new_skb);
1796	} else {
1797	if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1798	proto = PPP_VJC_COMP;
1799	cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1800	} else {
1801	proto = PPP_VJC_UNCOMP;
1802	cp[0] = skb->data[2];
1803	}
1804	consume_skb(skb);
1805	skb = new_skb;
1806	cp = skb_put(skb, len: len + 2);
1807	cp[0] = 0;
1808	cp[1] = proto;
1809	}
1810	break;
1811
1812	case PPP_CCP:
1813	/* peek at outbound CCP frames */
1814	ppp_ccp_peek(ppp, skb, inbound: 0);
1815	break;
1816	}
1817
1818	/* try to do packet compression */
1819	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1820	proto != PPP_LCP && proto != PPP_CCP) {
1821	if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1822	if (net_ratelimit())
1823	netdev_err(dev: ppp->dev,
1824	format: "ppp: compression required but "
1825	"down - pkt dropped.\n");
1826	goto drop;
1827	}
1828	skb = pad_compress_skb(ppp, skb);
1829	if (!skb)
1830	goto drop;
1831	}
1832
1833	/*
1834	* If we are waiting for traffic (demand dialling),
1835	* queue it up for pppd to receive.
1836	*/
1837	if (ppp->flags & SC_LOOP_TRAFFIC) {
1838	if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1839	goto drop;
1840	skb_queue_tail(list: &ppp->file.rq, newsk: skb);
1841	wake_up_interruptible(&ppp->file.rwait);
1842	return;
1843	}
1844
1845	ppp->xmit_pending = skb;
1846	ppp_push(ppp);
1847	return;
1848
1849	drop:
1850	kfree_skb(skb);
1851	++ppp->dev->stats.tx_errors;
1852	}
1853
1854	/*
1855	* Try to send the frame in xmit_pending.
1856	* The caller should have the xmit path locked.
1857	*/
1858	static void
1859	ppp_push(struct ppp *ppp)
1860	{
1861	struct list_head *list;
1862	struct channel *pch;
1863	struct sk_buff *skb = ppp->xmit_pending;
1864
1865	if (!skb)
1866	return;
1867
1868	list = &ppp->channels;
1869	if (list_empty(head: list)) {
1870	/* nowhere to send the packet, just drop it */
1871	ppp->xmit_pending = NULL;
1872	kfree_skb(skb);
1873	return;
1874	}
1875
1876	if ((ppp->flags & SC_MULTILINK) == 0) {
1877	/* not doing multilink: send it down the first channel */
1878	list = list->next;
1879	pch = list_entry(list, struct channel, clist);
1880
1881	spin_lock(lock: &pch->downl);
1882	if (pch->chan) {
1883	if (pch->chan->ops->start_xmit(pch->chan, skb))
1884	ppp->xmit_pending = NULL;
1885	} else {
1886	/* channel got unregistered */
1887	kfree_skb(skb);
1888	ppp->xmit_pending = NULL;
1889	}
1890	spin_unlock(lock: &pch->downl);
1891	return;
1892	}
1893
1894	#ifdef CONFIG_PPP_MULTILINK
1895	/* Multilink: fragment the packet over as many links
1896	as can take the packet at the moment. */
1897	if (!ppp_mp_explode(ppp, skb))
1898	return;
1899	#endif /* CONFIG_PPP_MULTILINK */
1900
1901	ppp->xmit_pending = NULL;
1902	kfree_skb(skb);
1903	}
1904
1905	#ifdef CONFIG_PPP_MULTILINK
1906	static bool mp_protocol_compress __read_mostly = true;
1907	module_param(mp_protocol_compress, bool, 0644);
1908	MODULE_PARM_DESC(mp_protocol_compress,
1909	"compress protocol id in multilink fragments");
1910
1911	/*
1912	* Divide a packet to be transmitted into fragments and
1913	* send them out the individual links.
1914	*/
1915	static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1916	{
1917	int len, totlen;
1918	int i, bits, hdrlen, mtu;
1919	int flen;
1920	int navail, nfree, nzero;
1921	int nbigger;
1922	int totspeed;
1923	int totfree;
1924	unsigned char *p, *q;
1925	struct list_head *list;
1926	struct channel *pch;
1927	struct sk_buff *frag;
1928	struct ppp_channel *chan;
1929
1930	totspeed = 0; /*total bitrate of the bundle*/
1931	nfree = 0; /* # channels which have no packet already queued */
1932	navail = 0; /* total # of usable channels (not deregistered) */
1933	nzero = 0; /* number of channels with zero speed associated*/
1934	totfree = 0; /*total # of channels available and
1935	*having no queued packets before
1936	*starting the fragmentation*/
1937
1938	hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1939	i = 0;
1940	list_for_each_entry(pch, &ppp->channels, clist) {
1941	if (pch->chan) {
1942	pch->avail = 1;
1943	navail++;
1944	pch->speed = pch->chan->speed;
1945	} else {
1946	pch->avail = 0;
1947	}
1948	if (pch->avail) {
1949	if (skb_queue_empty(list: &pch->file.xq) ||
1950	!pch->had_frag) {
1951	if (pch->speed == 0)
1952	nzero++;
1953	else
1954	totspeed += pch->speed;
1955
1956	pch->avail = 2;
1957	++nfree;
1958	++totfree;
1959	}
1960	if (!pch->had_frag && i < ppp->nxchan)
1961	ppp->nxchan = i;
1962	}
1963	++i;
1964	}
1965	/*
1966	* Don't start sending this packet unless at least half of
1967	* the channels are free. This gives much better TCP
1968	* performance if we have a lot of channels.
1969	*/
1970	if (nfree == 0 || nfree < navail / 2)
1971	return 0; /* can't take now, leave it in xmit_pending */
1972
1973	/* Do protocol field compression */
1974	p = skb->data;
1975	len = skb->len;
1976	if (*p == 0 && mp_protocol_compress) {
1977	++p;
1978	--len;
1979	}
1980
1981	totlen = len;
1982	nbigger = len % nfree;
1983
1984	/* skip to the channel after the one we last used
1985	and start at that one */
1986	list = &ppp->channels;
1987	for (i = 0; i < ppp->nxchan; ++i) {
1988	list = list->next;
1989	if (list == &ppp->channels) {
1990	i = 0;
1991	break;
1992	}
1993	}
1994
1995	/* create a fragment for each channel */
1996	bits = B;
1997	while (len > 0) {
1998	list = list->next;
1999	if (list == &ppp->channels) {
2000	i = 0;
2001	continue;
2002	}
2003	pch = list_entry(list, struct channel, clist);
2004	++i;
2005	if (!pch->avail)
2006	continue;
2007
2008	/*
2009	* Skip this channel if it has a fragment pending already and
2010	* we haven't given a fragment to all of the free channels.
2011	*/
2012	if (pch->avail == 1) {
2013	if (nfree > 0)
2014	continue;
2015	} else {
2016	pch->avail = 1;
2017	}
2018
2019	/* check the channel's mtu and whether it is still attached. */
2020	spin_lock(lock: &pch->downl);
2021	if (pch->chan == NULL) {
2022	/* can't use this channel, it's being deregistered */
2023	if (pch->speed == 0)
2024	nzero--;
2025	else
2026	totspeed -= pch->speed;
2027
2028	spin_unlock(lock: &pch->downl);
2029	pch->avail = 0;
2030	totlen = len;
2031	totfree--;
2032	nfree--;
2033	if (--navail == 0)
2034	break;
2035	continue;
2036	}
2037
2038	/*
2039	*if the channel speed is not set divide
2040	*the packet evenly among the free channels;
2041	*otherwise divide it according to the speed
2042	*of the channel we are going to transmit on
2043	*/
2044	flen = len;
2045	if (nfree > 0) {
2046	if (pch->speed == 0) {
2047	flen = len/nfree;
2048	if (nbigger > 0) {
2049	flen++;
2050	nbigger--;
2051	}
2052	} else {
2053	flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2054	((totspeed*totfree)/pch->speed)) - hdrlen;
2055	if (nbigger > 0) {
2056	flen += ((totfree - nzero)*pch->speed)/totspeed;
2057	nbigger -= ((totfree - nzero)*pch->speed)/
2058	totspeed;
2059	}
2060	}
2061	nfree--;
2062	}
2063
2064	/*
2065	*check if we are on the last channel or
2066	*we exceded the length of the data to
2067	*fragment
2068	*/
2069	if ((nfree <= 0) || (flen > len))
2070	flen = len;
2071	/*
2072	*it is not worth to tx on slow channels:
2073	*in that case from the resulting flen according to the
2074	*above formula will be equal or less than zero.
2075	*Skip the channel in this case
2076	*/
2077	if (flen <= 0) {
2078	pch->avail = 2;
2079	spin_unlock(lock: &pch->downl);
2080	continue;
2081	}
2082
2083	/*
2084	* hdrlen includes the 2-byte PPP protocol field, but the
2085	* MTU counts only the payload excluding the protocol field.
2086	* (RFC1661 Section 2)
2087	*/
2088	mtu = pch->chan->mtu - (hdrlen - 2);
2089	if (mtu < 4)
2090	mtu = 4;
2091	if (flen > mtu)
2092	flen = mtu;
2093	if (flen == len)
2094	bits |= E;
2095	frag = alloc_skb(size: flen + hdrlen + (flen == 0), GFP_ATOMIC);
2096	if (!frag)
2097	goto noskb;
2098	q = skb_put(skb: frag, len: flen + hdrlen);
2099
2100	/* make the MP header */
2101	put_unaligned_be16(PPP_MP, p: q);
2102	if (ppp->flags & SC_MP_XSHORTSEQ) {
2103	q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2104	q[3] = ppp->nxseq;
2105	} else {
2106	q[2] = bits;
2107	q[3] = ppp->nxseq >> 16;
2108	q[4] = ppp->nxseq >> 8;
2109	q[5] = ppp->nxseq;
2110	}
2111
2112	memcpy(q + hdrlen, p, flen);
2113
2114	/* try to send it down the channel */
2115	chan = pch->chan;
2116	if (!skb_queue_empty(list: &pch->file.xq) ||
2117	!chan->ops->start_xmit(chan, frag))
2118	skb_queue_tail(list: &pch->file.xq, newsk: frag);
2119	pch->had_frag = 1;
2120	p += flen;
2121	len -= flen;
2122	++ppp->nxseq;
2123	bits = 0;
2124	spin_unlock(lock: &pch->downl);
2125	}
2126	ppp->nxchan = i;
2127
2128	return 1;
2129
2130	noskb:
2131	spin_unlock(lock: &pch->downl);
2132	if (ppp->debug & 1)
2133	netdev_err(dev: ppp->dev, format: "PPP: no memory (fragment)\n");
2134	++ppp->dev->stats.tx_errors;
2135	++ppp->nxseq;
2136	return 1; /* abandon the frame */
2137	}
2138	#endif /* CONFIG_PPP_MULTILINK */
2139
2140	/* Try to send data out on a channel */
2141	static void __ppp_channel_push(struct channel *pch)
2142	{
2143	struct sk_buff *skb;
2144	struct ppp *ppp;
2145
2146	spin_lock(lock: &pch->downl);
2147	if (pch->chan) {
2148	while (!skb_queue_empty(list: &pch->file.xq)) {
2149	skb = skb_dequeue(list: &pch->file.xq);
2150	if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2151	/* put the packet back and try again later */
2152	skb_queue_head(list: &pch->file.xq, newsk: skb);
2153	break;
2154	}
2155	}
2156	} else {
2157	/* channel got deregistered */
2158	skb_queue_purge(list: &pch->file.xq);
2159	}
2160	spin_unlock(lock: &pch->downl);
2161	/* see if there is anything from the attached unit to be sent */
2162	if (skb_queue_empty(list: &pch->file.xq)) {
2163	ppp = pch->ppp;
2164	if (ppp)
2165	__ppp_xmit_process(ppp, NULL);
2166	}
2167	}
2168
2169	static void ppp_channel_push(struct channel *pch)
2170	{
2171	read_lock_bh(&pch->upl);
2172	if (pch->ppp) {
2173	(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
2174	__ppp_channel_push(pch);
2175	(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
2176	} else {
2177	__ppp_channel_push(pch);
2178	}
2179	read_unlock_bh(&pch->upl);
2180	}
2181
2182	/*
2183	* Receive-side routines.
2184	*/
2185
2186	struct ppp_mp_skb_parm {
2187	u32 sequence;
2188	u8 BEbits;
2189	};
2190	#define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
2191
2192	static inline void
2193	ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2194	{
2195	ppp_recv_lock(ppp);
2196	if (!ppp->closing)
2197	ppp_receive_frame(ppp, skb, pch);
2198	else
2199	kfree_skb(skb);
2200	ppp_recv_unlock(ppp);
2201	}
2202
2203	/**
2204	* __ppp_decompress_proto - Decompress protocol field, slim version.
2205	* @skb: Socket buffer where protocol field should be decompressed. It must have
2206	* at least 1 byte of head room and 1 byte of linear data. First byte of
2207	* data must be a protocol field byte.
2208	*
2209	* Decompress protocol field in PPP header if it's compressed, e.g. when
2210	* Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2211	* length are done in this function.
2212	*/
2213	static void __ppp_decompress_proto(struct sk_buff *skb)
2214	{
2215	if (skb->data[0] & 0x01)
2216	*(u8 *)skb_push(skb, len: 1) = 0x00;
2217	}
2218
2219	/**
2220	* ppp_decompress_proto - Check skb data room and decompress protocol field.
2221	* @skb: Socket buffer where protocol field should be decompressed. First byte
2222	* of data must be a protocol field byte.
2223	*
2224	* Decompress protocol field in PPP header if it's compressed, e.g. when
2225	* Protocol-Field-Compression (PFC) was negotiated. This function also makes
2226	* sure that skb data room is sufficient for Protocol field, before and after
2227	* decompression.
2228	*
2229	* Return: true - decompressed successfully, false - not enough room in skb.
2230	*/
2231	static bool ppp_decompress_proto(struct sk_buff *skb)
2232	{
2233	/* At least one byte should be present (if protocol is compressed) */
2234	if (!pskb_may_pull(skb, len: 1))
2235	return false;
2236
2237	__ppp_decompress_proto(skb);
2238
2239	/* Protocol field should occupy 2 bytes when not compressed */
2240	return pskb_may_pull(skb, len: 2);
2241	}
2242
2243	/* Attempt to handle a frame via. a bridged channel, if one exists.
2244	* If the channel is bridged, the frame is consumed by the bridge.
2245	* If not, the caller must handle the frame by normal recv mechanisms.
2246	* Returns true if the frame is consumed, false otherwise.
2247	*/
2248	static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2249	{
2250	struct channel *pchb;
2251
2252	rcu_read_lock();
2253	pchb = rcu_dereference(pch->bridge);
2254	if (!pchb)
2255	goto out_rcu;
2256
2257	spin_lock(lock: &pchb->downl);
2258	if (!pchb->chan) {
2259	/* channel got unregistered */
2260	kfree_skb(skb);
2261	goto outl;
2262	}
2263
2264	skb_scrub_packet(skb, xnet: !net_eq(net1: pch->chan_net, net2: pchb->chan_net));
2265	if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2266	kfree_skb(skb);
2267
2268	outl:
2269	spin_unlock(lock: &pchb->downl);
2270	out_rcu:
2271	rcu_read_unlock();
2272
2273	/* If pchb is set then we've consumed the packet */
2274	return !!pchb;
2275	}
2276
2277	void
2278	ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2279	{
2280	struct channel *pch = chan->ppp;
2281	int proto;
2282
2283	if (!pch) {
2284	kfree_skb(skb);
2285	return;
2286	}
2287
2288	/* If the channel is bridged, transmit via. bridge */
2289	if (ppp_channel_bridge_input(pch, skb))
2290	return;
2291
2292	read_lock_bh(&pch->upl);
2293	if (!ppp_decompress_proto(skb)) {
2294	kfree_skb(skb);
2295	if (pch->ppp) {
2296	++pch->ppp->dev->stats.rx_length_errors;
2297	ppp_receive_error(ppp: pch->ppp);
2298	}
2299	goto done;
2300	}
2301
2302	proto = PPP_PROTO(skb);
2303	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2304	/* put it on the channel queue */
2305	skb_queue_tail(list: &pch->file.rq, newsk: skb);
2306	/* drop old frames if queue too long */
2307	while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2308	(skb = skb_dequeue(list: &pch->file.rq)))
2309	kfree_skb(skb);
2310	wake_up_interruptible(&pch->file.rwait);
2311	} else {
2312	ppp_do_recv(ppp: pch->ppp, skb, pch);
2313	}
2314
2315	done:
2316	read_unlock_bh(&pch->upl);
2317	}
2318
2319	/* Put a 0-length skb in the receive queue as an error indication */
2320	void
2321	ppp_input_error(struct ppp_channel *chan, int code)
2322	{
2323	struct channel *pch = chan->ppp;
2324	struct sk_buff *skb;
2325
2326	if (!pch)
2327	return;
2328
2329	read_lock_bh(&pch->upl);
2330	if (pch->ppp) {
2331	skb = alloc_skb(size: 0, GFP_ATOMIC);
2332	if (skb) {
2333	skb->len = 0; /* probably unnecessary */
2334	skb->cb[0] = code;
2335	ppp_do_recv(ppp: pch->ppp, skb, pch);
2336	}
2337	}
2338	read_unlock_bh(&pch->upl);
2339	}
2340
2341	/*
2342	* We come in here to process a received frame.
2343	* The receive side of the ppp unit is locked.
2344	*/
2345	static void
2346	ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2347	{
2348	/* note: a 0-length skb is used as an error indication */
2349	if (skb->len > 0) {
2350	skb_checksum_complete_unset(skb);
2351	#ifdef CONFIG_PPP_MULTILINK
2352	/* XXX do channel-level decompression here */
2353	if (PPP_PROTO(skb) == PPP_MP)
2354	ppp_receive_mp_frame(ppp, skb, pch);
2355	else
2356	#endif /* CONFIG_PPP_MULTILINK */
2357	ppp_receive_nonmp_frame(ppp, skb);
2358	} else {
2359	kfree_skb(skb);
2360	ppp_receive_error(ppp);
2361	}
2362	}
2363
2364	static void
2365	ppp_receive_error(struct ppp *ppp)
2366	{
2367	++ppp->dev->stats.rx_errors;
2368	if (ppp->vj)
2369	slhc_toss(comp: ppp->vj);
2370	}
2371
2372	static void
2373	ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2374	{
2375	struct sk_buff *ns;
2376	int proto, len, npi;
2377
2378	/*
2379	* Decompress the frame, if compressed.
2380	* Note that some decompressors need to see uncompressed frames
2381	* that come in as well as compressed frames.
2382	*/
2383	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2384	(ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2385	skb = ppp_decompress_frame(ppp, skb);
2386
2387	if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2388	goto err;
2389
2390	/* At this point the "Protocol" field MUST be decompressed, either in
2391	* ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2392	*/
2393	proto = PPP_PROTO(skb);
2394	switch (proto) {
2395	case PPP_VJC_COMP:
2396	/* decompress VJ compressed packets */
2397	if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2398	goto err;
2399
2400	if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2401	/* copy to a new sk_buff with more tailroom */
2402	ns = dev_alloc_skb(length: skb->len + 128);
2403	if (!ns) {
2404	netdev_err(dev: ppp->dev, format: "PPP: no memory "
2405	"(VJ decomp)\n");
2406	goto err;
2407	}
2408	skb_reserve(skb: ns, len: 2);
2409	skb_copy_bits(skb, offset: 0, to: skb_put(skb: ns, len: skb->len), len: skb->len);
2410	consume_skb(skb);
2411	skb = ns;
2412	}
2413	else
2414	skb->ip_summed = CHECKSUM_NONE;
2415
2416	len = slhc_uncompress(comp: ppp->vj, icp: skb->data + 2, isize: skb->len - 2);
2417	if (len <= 0) {
2418	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2419	format: "PPP: VJ decompression error\n");
2420	goto err;
2421	}
2422	len += 2;
2423	if (len > skb->len)
2424	skb_put(skb, len: len - skb->len);
2425	else if (len < skb->len)
2426	skb_trim(skb, len);
2427	proto = PPP_IP;
2428	break;
2429
2430	case PPP_VJC_UNCOMP:
2431	if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2432	goto err;
2433
2434	/* Until we fix the decompressor need to make sure
2435	* data portion is linear.
2436	*/
2437	if (!pskb_may_pull(skb, len: skb->len))
2438	goto err;
2439
2440	if (slhc_remember(comp: ppp->vj, icp: skb->data + 2, isize: skb->len - 2) <= 0) {
2441	netdev_err(dev: ppp->dev, format: "PPP: VJ uncompressed error\n");
2442	goto err;
2443	}
2444	proto = PPP_IP;
2445	break;
2446
2447	case PPP_CCP:
2448	ppp_ccp_peek(ppp, skb, inbound: 1);
2449	break;
2450	}
2451
2452	++ppp->stats64.rx_packets;
2453	ppp->stats64.rx_bytes += skb->len - 2;
2454
2455	npi = proto_to_npindex(proto);
2456	if (npi < 0) {
2457	/* control or unknown frame - pass it to pppd */
2458	skb_queue_tail(list: &ppp->file.rq, newsk: skb);
2459	/* limit queue length by dropping old frames */
2460	while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2461	(skb = skb_dequeue(list: &ppp->file.rq)))
2462	kfree_skb(skb);
2463	/* wake up any process polling or blocking on read */
2464	wake_up_interruptible(&ppp->file.rwait);
2465
2466	} else {
2467	/* network protocol frame - give it to the kernel */
2468
2469	#ifdef CONFIG_PPP_FILTER
2470	/* check if the packet passes the pass and active filters */
2471	/* the filter instructions are constructed assuming
2472	a four-byte PPP header on each packet */
2473	if (ppp->pass_filter || ppp->active_filter) {
2474	if (skb_unclone(skb, GFP_ATOMIC))
2475	goto err;
2476
2477	*(u8 *)skb_push(skb, len: 2) = 0;
2478	if (ppp->pass_filter &&
2479	bpf_prog_run(prog: ppp->pass_filter, ctx: skb) == 0) {
2480	if (ppp->debug & 1)
2481	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2482	format: "PPP: inbound frame "
2483	"not passed\n");
2484	kfree_skb(skb);
2485	return;
2486	}
2487	if (!(ppp->active_filter &&
2488	bpf_prog_run(prog: ppp->active_filter, ctx: skb) == 0))
2489	ppp->last_recv = jiffies;
2490	__skb_pull(skb, len: 2);
2491	} else
2492	#endif /* CONFIG_PPP_FILTER */
2493	ppp->last_recv = jiffies;
2494
2495	if ((ppp->dev->flags & IFF_UP) == 0 ||
2496	ppp->npmode[npi] != NPMODE_PASS) {
2497	kfree_skb(skb);
2498	} else {
2499	/* chop off protocol */
2500	skb_pull_rcsum(skb, len: 2);
2501	skb->dev = ppp->dev;
2502	skb->protocol = htons(npindex_to_ethertype[npi]);
2503	skb_reset_mac_header(skb);
2504	skb_scrub_packet(skb, xnet: !net_eq(net1: ppp->ppp_net,
2505	net2: dev_net(dev: ppp->dev)));
2506	netif_rx(skb);
2507	}
2508	}
2509	return;
2510
2511	err:
2512	kfree_skb(skb);
2513	ppp_receive_error(ppp);
2514	}
2515
2516	static struct sk_buff *
2517	ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2518	{
2519	int proto = PPP_PROTO(skb);
2520	struct sk_buff *ns;
2521	int len;
2522
2523	/* Until we fix all the decompressor's need to make sure
2524	* data portion is linear.
2525	*/
2526	if (!pskb_may_pull(skb, len: skb->len))
2527	goto err;
2528
2529	if (proto == PPP_COMP) {
2530	int obuff_size;
2531
2532	switch(ppp->rcomp->compress_proto) {
2533	case CI_MPPE:
2534	obuff_size = ppp->mru + PPP_HDRLEN + 1;
2535	break;
2536	default:
2537	obuff_size = ppp->mru + PPP_HDRLEN;
2538	break;
2539	}
2540
2541	ns = dev_alloc_skb(length: obuff_size);
2542	if (!ns) {
2543	netdev_err(dev: ppp->dev, format: "ppp_decompress_frame: "
2544	"no memory\n");
2545	goto err;
2546	}
2547	/* the decompressor still expects the A/C bytes in the hdr */
2548	len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2549	skb->len + 2, ns->data, obuff_size);
2550	if (len < 0) {
2551	/* Pass the compressed frame to pppd as an
2552	error indication. */
2553	if (len == DECOMP_FATALERROR)
2554	ppp->rstate |= SC_DC_FERROR;
2555	kfree_skb(skb: ns);
2556	goto err;
2557	}
2558
2559	consume_skb(skb);
2560	skb = ns;
2561	skb_put(skb, len);
2562	skb_pull(skb, len: 2); /* pull off the A/C bytes */
2563
2564	/* Don't call __ppp_decompress_proto() here, but instead rely on
2565	* corresponding algo (mppe/bsd/deflate) to decompress it.
2566	*/
2567	} else {
2568	/* Uncompressed frame - pass to decompressor so it
2569	can update its dictionary if necessary. */
2570	if (ppp->rcomp->incomp)
2571	ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2572	skb->len + 2);
2573	}
2574
2575	return skb;
2576
2577	err:
2578	ppp->rstate |= SC_DC_ERROR;
2579	ppp_receive_error(ppp);
2580	return skb;
2581	}
2582
2583	#ifdef CONFIG_PPP_MULTILINK
2584	/*
2585	* Receive a multilink frame.
2586	* We put it on the reconstruction queue and then pull off
2587	* as many completed frames as we can.
2588	*/
2589	static void
2590	ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2591	{
2592	u32 mask, seq;
2593	struct channel *ch;
2594	int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2595
2596	if (!pskb_may_pull(skb, len: mphdrlen + 1) || ppp->mrru == 0)
2597	goto err; /* no good, throw it away */
2598
2599	/* Decode sequence number and begin/end bits */
2600	if (ppp->flags & SC_MP_SHORTSEQ) {
2601	seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2602	mask = 0xfff;
2603	} else {
2604	seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2605	mask = 0xffffff;
2606	}
2607	PPP_MP_CB(skb)->BEbits = skb->data[2];
2608	skb_pull(skb, len: mphdrlen); /* pull off PPP and MP headers */
2609
2610	/*
2611	* Do protocol ID decompression on the first fragment of each packet.
2612	* We have to do that here, because ppp_receive_nonmp_frame() expects
2613	* decompressed protocol field.
2614	*/
2615	if (PPP_MP_CB(skb)->BEbits & B)
2616	__ppp_decompress_proto(skb);
2617
2618	/*
2619	* Expand sequence number to 32 bits, making it as close
2620	* as possible to ppp->minseq.
2621	*/
2622	seq |= ppp->minseq & ~mask;
2623	if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2624	seq += mask + 1;
2625	else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2626	seq -= mask + 1; /* should never happen */
2627	PPP_MP_CB(skb)->sequence = seq;
2628	pch->lastseq = seq;
2629
2630	/*
2631	* If this packet comes before the next one we were expecting,
2632	* drop it.
2633	*/
2634	if (seq_before(seq, ppp->nextseq)) {
2635	kfree_skb(skb);
2636	++ppp->dev->stats.rx_dropped;
2637	ppp_receive_error(ppp);
2638	return;
2639	}
2640
2641	/*
2642	* Reevaluate minseq, the minimum over all channels of the
2643	* last sequence number received on each channel. Because of
2644	* the increasing sequence number rule, we know that any fragment
2645	* before `minseq' which hasn't arrived is never going to arrive.
2646	* The list of channels can't change because we have the receive
2647	* side of the ppp unit locked.
2648	*/
2649	list_for_each_entry(ch, &ppp->channels, clist) {
2650	if (seq_before(ch->lastseq, seq))
2651	seq = ch->lastseq;
2652	}
2653	if (seq_before(ppp->minseq, seq))
2654	ppp->minseq = seq;
2655
2656	/* Put the fragment on the reconstruction queue */
2657	ppp_mp_insert(ppp, skb);
2658
2659	/* If the queue is getting long, don't wait any longer for packets
2660	before the start of the queue. */
2661	if (skb_queue_len(list_: &ppp->mrq) >= PPP_MP_MAX_QLEN) {
2662	struct sk_buff *mskb = skb_peek(list_: &ppp->mrq);
2663	if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2664	ppp->minseq = PPP_MP_CB(mskb)->sequence;
2665	}
2666
2667	/* Pull completed packets off the queue and receive them. */
2668	while ((skb = ppp_mp_reconstruct(ppp))) {
2669	if (pskb_may_pull(skb, len: 2))
2670	ppp_receive_nonmp_frame(ppp, skb);
2671	else {
2672	++ppp->dev->stats.rx_length_errors;
2673	kfree_skb(skb);
2674	ppp_receive_error(ppp);
2675	}
2676	}
2677
2678	return;
2679
2680	err:
2681	kfree_skb(skb);
2682	ppp_receive_error(ppp);
2683	}
2684
2685	/*
2686	* Insert a fragment on the MP reconstruction queue.
2687	* The queue is ordered by increasing sequence number.
2688	*/
2689	static void
2690	ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2691	{
2692	struct sk_buff *p;
2693	struct sk_buff_head *list = &ppp->mrq;
2694	u32 seq = PPP_MP_CB(skb)->sequence;
2695
2696	/* N.B. we don't need to lock the list lock because we have the
2697	ppp unit receive-side lock. */
2698	skb_queue_walk(list, p) {
2699	if (seq_before(seq, PPP_MP_CB(p)->sequence))
2700	break;
2701	}
2702	__skb_queue_before(list, next: p, newsk: skb);
2703	}
2704
2705	/*
2706	* Reconstruct a packet from the MP fragment queue.
2707	* We go through increasing sequence numbers until we find a
2708	* complete packet, or we get to the sequence number for a fragment
2709	* which hasn't arrived but might still do so.
2710	*/
2711	static struct sk_buff *
2712	ppp_mp_reconstruct(struct ppp *ppp)
2713	{
2714	u32 seq = ppp->nextseq;
2715	u32 minseq = ppp->minseq;
2716	struct sk_buff_head *list = &ppp->mrq;
2717	struct sk_buff *p, *tmp;
2718	struct sk_buff *head, *tail;
2719	struct sk_buff *skb = NULL;
2720	int lost = 0, len = 0;
2721
2722	if (ppp->mrru == 0) /* do nothing until mrru is set */
2723	return NULL;
2724	head = __skb_peek(list_: list);
2725	tail = NULL;
2726	skb_queue_walk_safe(list, p, tmp) {
2727	again:
2728	if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2729	/* this can't happen, anyway ignore the skb */
2730	netdev_err(dev: ppp->dev, format: "ppp_mp_reconstruct bad "
2731	"seq %u < %u\n",
2732	PPP_MP_CB(p)->sequence, seq);
2733	__skb_unlink(skb: p, list);
2734	kfree_skb(skb: p);
2735	continue;
2736	}
2737	if (PPP_MP_CB(p)->sequence != seq) {
2738	u32 oldseq;
2739	/* Fragment `seq' is missing. If it is after
2740	minseq, it might arrive later, so stop here. */
2741	if (seq_after(seq, minseq))
2742	break;
2743	/* Fragment `seq' is lost, keep going. */
2744	lost = 1;
2745	oldseq = seq;
2746	seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2747	minseq + 1: PPP_MP_CB(p)->sequence;
2748
2749	if (ppp->debug & 1)
2750	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2751	format: "lost frag %u..%u\n",
2752	oldseq, seq-1);
2753
2754	goto again;
2755	}
2756
2757	/*
2758	* At this point we know that all the fragments from
2759	* ppp->nextseq to seq are either present or lost.
2760	* Also, there are no complete packets in the queue
2761	* that have no missing fragments and end before this
2762	* fragment.
2763	*/
2764
2765	/* B bit set indicates this fragment starts a packet */
2766	if (PPP_MP_CB(p)->BEbits & B) {
2767	head = p;
2768	lost = 0;
2769	len = 0;
2770	}
2771
2772	len += p->len;
2773
2774	/* Got a complete packet yet? */
2775	if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2776	(PPP_MP_CB(head)->BEbits & B)) {
2777	if (len > ppp->mrru + 2) {
2778	++ppp->dev->stats.rx_length_errors;
2779	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2780	format: "PPP: reconstructed packet"
2781	" is too long (%d)\n", len);
2782	} else {
2783	tail = p;
2784	break;
2785	}
2786	ppp->nextseq = seq + 1;
2787	}
2788
2789	/*
2790	* If this is the ending fragment of a packet,
2791	* and we haven't found a complete valid packet yet,
2792	* we can discard up to and including this fragment.
2793	*/
2794	if (PPP_MP_CB(p)->BEbits & E) {
2795	struct sk_buff *tmp2;
2796
2797	skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2798	if (ppp->debug & 1)
2799	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2800	format: "discarding frag %u\n",
2801	PPP_MP_CB(p)->sequence);
2802	__skb_unlink(skb: p, list);
2803	kfree_skb(skb: p);
2804	}
2805	head = skb_peek(list_: list);
2806	if (!head)
2807	break;
2808	}
2809	++seq;
2810	}
2811
2812	/* If we have a complete packet, copy it all into one skb. */
2813	if (tail != NULL) {
2814	/* If we have discarded any fragments,
2815	signal a receive error. */
2816	if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2817	skb_queue_walk_safe(list, p, tmp) {
2818	if (p == head)
2819	break;
2820	if (ppp->debug & 1)
2821	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2822	format: "discarding frag %u\n",
2823	PPP_MP_CB(p)->sequence);
2824	__skb_unlink(skb: p, list);
2825	kfree_skb(skb: p);
2826	}
2827
2828	if (ppp->debug & 1)
2829	netdev_printk(KERN_DEBUG, dev: ppp->dev,
2830	format: " missed pkts %u..%u\n",
2831	ppp->nextseq,
2832	PPP_MP_CB(head)->sequence-1);
2833	++ppp->dev->stats.rx_dropped;
2834	ppp_receive_error(ppp);
2835	}
2836
2837	skb = head;
2838	if (head != tail) {
2839	struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2840	p = skb_queue_next(list, skb: head);
2841	__skb_unlink(skb, list);
2842	skb_queue_walk_from_safe(list, p, tmp) {
2843	__skb_unlink(skb: p, list);
2844	*fragpp = p;
2845	p->next = NULL;
2846	fragpp = &p->next;
2847
2848	skb->len += p->len;
2849	skb->data_len += p->len;
2850	skb->truesize += p->truesize;
2851
2852	if (p == tail)
2853	break;
2854	}
2855	} else {
2856	__skb_unlink(skb, list);
2857	}
2858
2859	ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2860	}
2861
2862	return skb;
2863	}
2864	#endif /* CONFIG_PPP_MULTILINK */
2865
2866	/*
2867	* Channel interface.
2868	*/
2869
2870	/* Create a new, unattached ppp channel. */
2871	int ppp_register_channel(struct ppp_channel *chan)
2872	{
2873	return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2874	}
2875
2876	/* Create a new, unattached ppp channel for specified net. */
2877	int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2878	{
2879	struct channel *pch;
2880	struct ppp_net *pn;
2881
2882	pch = kzalloc(size: sizeof(struct channel), GFP_KERNEL);
2883	if (!pch)
2884	return -ENOMEM;
2885
2886	pn = ppp_pernet(net);
2887
2888	pch->ppp = NULL;
2889	pch->chan = chan;
2890	pch->chan_net = get_net_track(net, tracker: &pch->ns_tracker, GFP_KERNEL);
2891	chan->ppp = pch;
2892	init_ppp_file(pf: &pch->file, kind: CHANNEL);
2893	pch->file.hdrlen = chan->hdrlen;
2894	#ifdef CONFIG_PPP_MULTILINK
2895	pch->lastseq = -1;
2896	#endif /* CONFIG_PPP_MULTILINK */
2897	init_rwsem(&pch->chan_sem);
2898	spin_lock_init(&pch->downl);
2899	rwlock_init(&pch->upl);
2900
2901	spin_lock_bh(lock: &pn->all_channels_lock);
2902	pch->file.index = ++pn->last_channel_index;
2903	list_add(new: &pch->list, head: &pn->new_channels);
2904	atomic_inc(v: &channel_count);
2905	spin_unlock_bh(lock: &pn->all_channels_lock);
2906
2907	return 0;
2908	}
2909
2910	/*
2911	* Return the index of a channel.
2912	*/
2913	int ppp_channel_index(struct ppp_channel *chan)
2914	{
2915	struct channel *pch = chan->ppp;
2916
2917	if (pch)
2918	return pch->file.index;
2919	return -1;
2920	}
2921
2922	/*
2923	* Return the PPP unit number to which a channel is connected.
2924	*/
2925	int ppp_unit_number(struct ppp_channel *chan)
2926	{
2927	struct channel *pch = chan->ppp;
2928	int unit = -1;
2929
2930	if (pch) {
2931	read_lock_bh(&pch->upl);
2932	if (pch->ppp)
2933	unit = pch->ppp->file.index;
2934	read_unlock_bh(&pch->upl);
2935	}
2936	return unit;
2937	}
2938
2939	/*
2940	* Return the PPP device interface name of a channel.
2941	*/
2942	char *ppp_dev_name(struct ppp_channel *chan)
2943	{
2944	struct channel *pch = chan->ppp;
2945	char *name = NULL;
2946
2947	if (pch) {
2948	read_lock_bh(&pch->upl);
2949	if (pch->ppp && pch->ppp->dev)
2950	name = pch->ppp->dev->name;
2951	read_unlock_bh(&pch->upl);
2952	}
2953	return name;
2954	}
2955
2956
2957	/*
2958	* Disconnect a channel from the generic layer.
2959	* This must be called in process context.
2960	*/
2961	void
2962	ppp_unregister_channel(struct ppp_channel *chan)
2963	{
2964	struct channel *pch = chan->ppp;
2965	struct ppp_net *pn;
2966
2967	if (!pch)
2968	return; /* should never happen */
2969
2970	chan->ppp = NULL;
2971
2972	/*
2973	* This ensures that we have returned from any calls into
2974	* the channel's start_xmit or ioctl routine before we proceed.
2975	*/
2976	down_write(sem: &pch->chan_sem);
2977	spin_lock_bh(lock: &pch->downl);
2978	pch->chan = NULL;
2979	spin_unlock_bh(lock: &pch->downl);
2980	up_write(sem: &pch->chan_sem);
2981	ppp_disconnect_channel(pch);
2982
2983	pn = ppp_pernet(net: pch->chan_net);
2984	spin_lock_bh(lock: &pn->all_channels_lock);
2985	list_del(entry: &pch->list);
2986	spin_unlock_bh(lock: &pn->all_channels_lock);
2987
2988	ppp_unbridge_channels(pch);
2989
2990	pch->file.dead = 1;
2991	wake_up_interruptible(&pch->file.rwait);
2992
2993	if (refcount_dec_and_test(r: &pch->file.refcnt))
2994	ppp_destroy_channel(pch);
2995	}
2996
2997	/*
2998	* Callback from a channel when it can accept more to transmit.
2999	* This should be called at BH/softirq level, not interrupt level.
3000	*/
3001	void
3002	ppp_output_wakeup(struct ppp_channel *chan)
3003	{
3004	struct channel *pch = chan->ppp;
3005
3006	if (!pch)
3007	return;
3008	ppp_channel_push(pch);
3009	}
3010
3011	/*
3012	* Compression control.
3013	*/
3014
3015	/* Process the PPPIOCSCOMPRESS ioctl. */
3016	static int
3017	ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3018	{
3019	int err = -EFAULT;
3020	struct compressor *cp, *ocomp;
3021	void *state, *ostate;
3022	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3023
3024	if (data->length > CCP_MAX_OPTION_LENGTH)
3025	goto out;
3026	if (copy_from_user(to: ccp_option, from: data->ptr, n: data->length))
3027	goto out;
3028
3029	err = -EINVAL;
3030	if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3031	goto out;
3032
3033	cp = try_then_request_module(
3034	find_compressor(ccp_option[0]),
3035	"ppp-compress-%d", ccp_option[0]);
3036	if (!cp)
3037	goto out;
3038
3039	err = -ENOBUFS;
3040	if (data->transmit) {
3041	state = cp->comp_alloc(ccp_option, data->length);
3042	if (state) {
3043	ppp_xmit_lock(ppp);
3044	ppp->xstate &= ~SC_COMP_RUN;
3045	ocomp = ppp->xcomp;
3046	ostate = ppp->xc_state;
3047	ppp->xcomp = cp;
3048	ppp->xc_state = state;
3049	ppp_xmit_unlock(ppp);
3050	if (ostate) {
3051	ocomp->comp_free(ostate);
3052	module_put(module: ocomp->owner);
3053	}
3054	err = 0;
3055	} else
3056	module_put(module: cp->owner);
3057
3058	} else {
3059	state = cp->decomp_alloc(ccp_option, data->length);
3060	if (state) {
3061	ppp_recv_lock(ppp);
3062	ppp->rstate &= ~SC_DECOMP_RUN;
3063	ocomp = ppp->rcomp;
3064	ostate = ppp->rc_state;
3065	ppp->rcomp = cp;
3066	ppp->rc_state = state;
3067	ppp_recv_unlock(ppp);
3068	if (ostate) {
3069	ocomp->decomp_free(ostate);
3070	module_put(module: ocomp->owner);
3071	}
3072	err = 0;
3073	} else
3074	module_put(module: cp->owner);
3075	}
3076
3077	out:
3078	return err;
3079	}
3080
3081	/*
3082	* Look at a CCP packet and update our state accordingly.
3083	* We assume the caller has the xmit or recv path locked.
3084	*/
3085	static void
3086	ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3087	{
3088	unsigned char *dp;
3089	int len;
3090
3091	if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3092	return; /* no header */
3093	dp = skb->data + 2;
3094
3095	switch (CCP_CODE(dp)) {
3096	case CCP_CONFREQ:
3097
3098	/* A ConfReq starts negotiation of compression
3099	* in one direction of transmission,
3100	* and hence brings it down...but which way?
3101	*
3102	* Remember:
3103	* A ConfReq indicates what the sender would like to receive
3104	*/
3105	if(inbound)
3106	/* He is proposing what I should send */
3107	ppp->xstate &= ~SC_COMP_RUN;
3108	else
3109	/* I am proposing to what he should send */
3110	ppp->rstate &= ~SC_DECOMP_RUN;
3111
3112	break;
3113
3114	case CCP_TERMREQ:
3115	case CCP_TERMACK:
3116	/*
3117	* CCP is going down, both directions of transmission
3118	*/
3119	ppp->rstate &= ~SC_DECOMP_RUN;
3120	ppp->xstate &= ~SC_COMP_RUN;
3121	break;
3122
3123	case CCP_CONFACK:
3124	if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3125	break;
3126	len = CCP_LENGTH(dp);
3127	if (!pskb_may_pull(skb, len: len + 2))
3128	return; /* too short */
3129	dp += CCP_HDRLEN;
3130	len -= CCP_HDRLEN;
3131	if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3132	break;
3133	if (inbound) {
3134	/* we will start receiving compressed packets */
3135	if (!ppp->rc_state)
3136	break;
3137	if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3138	ppp->file.index, 0, ppp->mru, ppp->debug)) {
3139	ppp->rstate |= SC_DECOMP_RUN;
3140	ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3141	}
3142	} else {
3143	/* we will soon start sending compressed packets */
3144	if (!ppp->xc_state)
3145	break;
3146	if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3147	ppp->file.index, 0, ppp->debug))
3148	ppp->xstate |= SC_COMP_RUN;
3149	}
3150	break;
3151
3152	case CCP_RESETACK:
3153	/* reset the [de]compressor */
3154	if ((ppp->flags & SC_CCP_UP) == 0)
3155	break;
3156	if (inbound) {
3157	if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3158	ppp->rcomp->decomp_reset(ppp->rc_state);
3159	ppp->rstate &= ~SC_DC_ERROR;
3160	}
3161	} else {
3162	if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3163	ppp->xcomp->comp_reset(ppp->xc_state);
3164	}
3165	break;
3166	}
3167	}
3168
3169	/* Free up compression resources. */
3170	static void
3171	ppp_ccp_closed(struct ppp *ppp)
3172	{
3173	void *xstate, *rstate;
3174	struct compressor *xcomp, *rcomp;
3175
3176	ppp_lock(ppp);
3177	ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3178	ppp->xstate = 0;
3179	xcomp = ppp->xcomp;
3180	xstate = ppp->xc_state;
3181	ppp->xc_state = NULL;
3182	ppp->rstate = 0;
3183	rcomp = ppp->rcomp;
3184	rstate = ppp->rc_state;
3185	ppp->rc_state = NULL;
3186	ppp_unlock(ppp);
3187
3188	if (xstate) {
3189	xcomp->comp_free(xstate);
3190	module_put(module: xcomp->owner);
3191	}
3192	if (rstate) {
3193	rcomp->decomp_free(rstate);
3194	module_put(module: rcomp->owner);
3195	}
3196	}
3197
3198	/* List of compressors. */
3199	static LIST_HEAD(compressor_list);
3200	static DEFINE_SPINLOCK(compressor_list_lock);
3201
3202	struct compressor_entry {
3203	struct list_head list;
3204	struct compressor *comp;
3205	};
3206
3207	static struct compressor_entry *
3208	find_comp_entry(int proto)
3209	{
3210	struct compressor_entry *ce;
3211
3212	list_for_each_entry(ce, &compressor_list, list) {
3213	if (ce->comp->compress_proto == proto)
3214	return ce;
3215	}
3216	return NULL;
3217	}
3218
3219	/* Register a compressor */
3220	int
3221	ppp_register_compressor(struct compressor *cp)
3222	{
3223	struct compressor_entry *ce;
3224	int ret;
3225	spin_lock(lock: &compressor_list_lock);
3226	ret = -EEXIST;
3227	if (find_comp_entry(proto: cp->compress_proto))
3228	goto out;
3229	ret = -ENOMEM;
3230	ce = kmalloc(size: sizeof(struct compressor_entry), GFP_ATOMIC);
3231	if (!ce)
3232	goto out;
3233	ret = 0;
3234	ce->comp = cp;
3235	list_add(new: &ce->list, head: &compressor_list);
3236	out:
3237	spin_unlock(lock: &compressor_list_lock);
3238	return ret;
3239	}
3240
3241	/* Unregister a compressor */
3242	void
3243	ppp_unregister_compressor(struct compressor *cp)
3244	{
3245	struct compressor_entry *ce;
3246
3247	spin_lock(lock: &compressor_list_lock);
3248	ce = find_comp_entry(proto: cp->compress_proto);
3249	if (ce && ce->comp == cp) {
3250	list_del(entry: &ce->list);
3251	kfree(objp: ce);
3252	}
3253	spin_unlock(lock: &compressor_list_lock);
3254	}
3255
3256	/* Find a compressor. */
3257	static struct compressor *
3258	find_compressor(int type)
3259	{
3260	struct compressor_entry *ce;
3261	struct compressor *cp = NULL;
3262
3263	spin_lock(lock: &compressor_list_lock);
3264	ce = find_comp_entry(proto: type);
3265	if (ce) {
3266	cp = ce->comp;
3267	if (!try_module_get(module: cp->owner))
3268	cp = NULL;
3269	}
3270	spin_unlock(lock: &compressor_list_lock);
3271	return cp;
3272	}
3273
3274	/*
3275	* Miscelleneous stuff.
3276	*/
3277
3278	static void
3279	ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3280	{
3281	struct slcompress *vj = ppp->vj;
3282
3283	memset(st, 0, sizeof(*st));
3284	st->p.ppp_ipackets = ppp->stats64.rx_packets;
3285	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3286	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
3287	st->p.ppp_opackets = ppp->stats64.tx_packets;
3288	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3289	st->p.ppp_obytes = ppp->stats64.tx_bytes;
3290	if (!vj)
3291	return;
3292	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3293	st->vj.vjs_compressed = vj->sls_o_compressed;
3294	st->vj.vjs_searches = vj->sls_o_searches;
3295	st->vj.vjs_misses = vj->sls_o_misses;
3296	st->vj.vjs_errorin = vj->sls_i_error;
3297	st->vj.vjs_tossed = vj->sls_i_tossed;
3298	st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3299	st->vj.vjs_compressedin = vj->sls_i_compressed;
3300	}
3301
3302	/*
3303	* Stuff for handling the lists of ppp units and channels
3304	* and for initialization.
3305	*/
3306
3307	/*
3308	* Create a new ppp interface unit. Fails if it can't allocate memory
3309	* or if there is already a unit with the requested number.
3310	* unit == -1 means allocate a new number.
3311	*/
3312	static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3313	{
3314	struct ppp_config conf = {
3315	.file = file,
3316	.unit = *unit,
3317	.ifname_is_set = false,
3318	};
3319	struct net_device *dev;
3320	struct ppp *ppp;
3321	int err;
3322
3323	dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3324	if (!dev) {
3325	err = -ENOMEM;
3326	goto err;
3327	}
3328	dev_net_set(dev, net);
3329	dev->rtnl_link_ops = &ppp_link_ops;
3330
3331	rtnl_lock();
3332
3333	err = ppp_dev_configure(src_net: net, dev, conf: &conf);
3334	if (err < 0)
3335	goto err_dev;
3336	ppp = netdev_priv(dev);
3337	*unit = ppp->file.index;
3338
3339	rtnl_unlock();
3340
3341	return 0;
3342
3343	err_dev:
3344	rtnl_unlock();
3345	free_netdev(dev);
3346	err:
3347	return err;
3348	}
3349
3350	/*
3351	* Initialize a ppp_file structure.
3352	*/
3353	static void
3354	init_ppp_file(struct ppp_file *pf, int kind)
3355	{
3356	pf->kind = kind;
3357	skb_queue_head_init(list: &pf->xq);
3358	skb_queue_head_init(list: &pf->rq);
3359	refcount_set(r: &pf->refcnt, n: 1);
3360	init_waitqueue_head(&pf->rwait);
3361	}
3362
3363	/*
3364	* Free the memory used by a ppp unit. This is only called once
3365	* there are no channels connected to the unit and no file structs
3366	* that reference the unit.
3367	*/
3368	static void ppp_destroy_interface(struct ppp *ppp)
3369	{
3370	atomic_dec(v: &ppp_unit_count);
3371
3372	if (!ppp->file.dead || ppp->n_channels) {
3373	/* "can't happen" */
3374	netdev_err(dev: ppp->dev, format: "ppp: destroying ppp struct %p "
3375	"but dead=%d n_channels=%d !\n",
3376	ppp, ppp->file.dead, ppp->n_channels);
3377	return;
3378	}
3379
3380	ppp_ccp_closed(ppp);
3381	if (ppp->vj) {
3382	slhc_free(comp: ppp->vj);
3383	ppp->vj = NULL;
3384	}
3385	skb_queue_purge(list: &ppp->file.xq);
3386	skb_queue_purge(list: &ppp->file.rq);
3387	#ifdef CONFIG_PPP_MULTILINK
3388	skb_queue_purge(list: &ppp->mrq);
3389	#endif /* CONFIG_PPP_MULTILINK */
3390	#ifdef CONFIG_PPP_FILTER
3391	if (ppp->pass_filter) {
3392	bpf_prog_destroy(fp: ppp->pass_filter);
3393	ppp->pass_filter = NULL;
3394	}
3395
3396	if (ppp->active_filter) {
3397	bpf_prog_destroy(fp: ppp->active_filter);
3398	ppp->active_filter = NULL;
3399	}
3400	#endif /* CONFIG_PPP_FILTER */
3401
3402	kfree_skb(skb: ppp->xmit_pending);
3403	free_percpu(pdata: ppp->xmit_recursion);
3404
3405	free_netdev(dev: ppp->dev);
3406	}
3407
3408	/*
3409	* Locate an existing ppp unit.
3410	* The caller should have locked the all_ppp_mutex.
3411	*/
3412	static struct ppp *
3413	ppp_find_unit(struct ppp_net *pn, int unit)
3414	{
3415	return unit_find(p: &pn->units_idr, n: unit);
3416	}
3417
3418	/*
3419	* Locate an existing ppp channel.
3420	* The caller should have locked the all_channels_lock.
3421	* First we look in the new_channels list, then in the
3422	* all_channels list. If found in the new_channels list,
3423	* we move it to the all_channels list. This is for speed
3424	* when we have a lot of channels in use.
3425	*/
3426	static struct channel *
3427	ppp_find_channel(struct ppp_net *pn, int unit)
3428	{
3429	struct channel *pch;
3430
3431	list_for_each_entry(pch, &pn->new_channels, list) {
3432	if (pch->file.index == unit) {
3433	list_move(list: &pch->list, head: &pn->all_channels);
3434	return pch;
3435	}
3436	}
3437
3438	list_for_each_entry(pch, &pn->all_channels, list) {
3439	if (pch->file.index == unit)
3440	return pch;
3441	}
3442
3443	return NULL;
3444	}
3445
3446	/*
3447	* Connect a PPP channel to a PPP interface unit.
3448	*/
3449	static int
3450	ppp_connect_channel(struct channel *pch, int unit)
3451	{
3452	struct ppp *ppp;
3453	struct ppp_net *pn;
3454	int ret = -ENXIO;
3455	int hdrlen;
3456
3457	pn = ppp_pernet(net: pch->chan_net);
3458
3459	mutex_lock(&pn->all_ppp_mutex);
3460	ppp = ppp_find_unit(pn, unit);
3461	if (!ppp)
3462	goto out;
3463	write_lock_bh(&pch->upl);
3464	ret = -EINVAL;
3465	if (pch->ppp ||
3466	rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3467	goto outl;
3468
3469	ppp_lock(ppp);
3470	spin_lock_bh(lock: &pch->downl);
3471	if (!pch->chan) {
3472	/* Don't connect unregistered channels */
3473	spin_unlock_bh(lock: &pch->downl);
3474	ppp_unlock(ppp);
3475	ret = -ENOTCONN;
3476	goto outl;
3477	}
3478	spin_unlock_bh(lock: &pch->downl);
3479	if (pch->file.hdrlen > ppp->file.hdrlen)
3480	ppp->file.hdrlen = pch->file.hdrlen;
3481	hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
3482	if (hdrlen > ppp->dev->hard_header_len)
3483	ppp->dev->hard_header_len = hdrlen;
3484	list_add_tail(new: &pch->clist, head: &ppp->channels);
3485	++ppp->n_channels;
3486	pch->ppp = ppp;
3487	refcount_inc(r: &ppp->file.refcnt);
3488	ppp_unlock(ppp);
3489	ret = 0;
3490
3491	outl:
3492	write_unlock_bh(&pch->upl);
3493	out:
3494	mutex_unlock(lock: &pn->all_ppp_mutex);
3495	return ret;
3496	}
3497
3498	/*
3499	* Disconnect a channel from its ppp unit.
3500	*/
3501	static int
3502	ppp_disconnect_channel(struct channel *pch)
3503	{
3504	struct ppp *ppp;
3505	int err = -EINVAL;
3506
3507	write_lock_bh(&pch->upl);
3508	ppp = pch->ppp;
3509	pch->ppp = NULL;
3510	write_unlock_bh(&pch->upl);
3511	if (ppp) {
3512	/* remove it from the ppp unit's list */
3513	ppp_lock(ppp);
3514	list_del(entry: &pch->clist);
3515	if (--ppp->n_channels == 0)
3516	wake_up_interruptible(&ppp->file.rwait);
3517	ppp_unlock(ppp);
3518	if (refcount_dec_and_test(r: &ppp->file.refcnt))
3519	ppp_destroy_interface(ppp);
3520	err = 0;
3521	}
3522	return err;
3523	}
3524
3525	/*
3526	* Free up the resources used by a ppp channel.
3527	*/
3528	static void ppp_destroy_channel(struct channel *pch)
3529	{
3530	put_net_track(net: pch->chan_net, tracker: &pch->ns_tracker);
3531	pch->chan_net = NULL;
3532
3533	atomic_dec(v: &channel_count);
3534
3535	if (!pch->file.dead) {
3536	/* "can't happen" */
3537	pr_err("ppp: destroying undead channel %p !\n", pch);
3538	return;
3539	}
3540	skb_queue_purge(list: &pch->file.xq);
3541	skb_queue_purge(list: &pch->file.rq);
3542	kfree(objp: pch);
3543	}
3544
3545	static void __exit ppp_cleanup(void)
3546	{
3547	/* should never happen */
3548	if (atomic_read(v: &ppp_unit_count) || atomic_read(v: &channel_count))
3549	pr_err("PPP: removing module but units remain!\n");
3550	rtnl_link_unregister(ops: &ppp_link_ops);
3551	unregister_chrdev(PPP_MAJOR, name: "ppp");
3552	device_destroy(cls: ppp_class, MKDEV(PPP_MAJOR, 0));
3553	class_destroy(cls: ppp_class);
3554	unregister_pernet_device(&ppp_net_ops);
3555	}
3556
3557	/*
3558	* Units handling. Caller must protect concurrent access
3559	* by holding all_ppp_mutex
3560	*/
3561
3562	/* associate pointer with specified number */
3563	static int unit_set(struct idr *p, void *ptr, int n)
3564	{
3565	int unit;
3566
3567	unit = idr_alloc(p, ptr, start: n, end: n + 1, GFP_KERNEL);
3568	if (unit == -ENOSPC)
3569	unit = -EINVAL;
3570	return unit;
3571	}
3572
3573	/* get new free unit number and associate pointer with it */
3574	static int unit_get(struct idr *p, void *ptr, int min)
3575	{
3576	return idr_alloc(p, ptr, start: min, end: 0, GFP_KERNEL);
3577	}
3578
3579	/* put unit number back to a pool */
3580	static void unit_put(struct idr *p, int n)
3581	{
3582	idr_remove(p, id: n);
3583	}
3584
3585	/* get pointer associated with the number */
3586	static void *unit_find(struct idr *p, int n)
3587	{
3588	return idr_find(p, id: n);
3589	}
3590
3591	/* Module/initialization stuff */
3592
3593	module_init(ppp_init);
3594	module_exit(ppp_cleanup);
3595
3596	EXPORT_SYMBOL(ppp_register_net_channel);
3597	EXPORT_SYMBOL(ppp_register_channel);
3598	EXPORT_SYMBOL(ppp_unregister_channel);
3599	EXPORT_SYMBOL(ppp_channel_index);
3600	EXPORT_SYMBOL(ppp_unit_number);
3601	EXPORT_SYMBOL(ppp_dev_name);
3602	EXPORT_SYMBOL(ppp_input);
3603	EXPORT_SYMBOL(ppp_input_error);
3604	EXPORT_SYMBOL(ppp_output_wakeup);
3605	EXPORT_SYMBOL(ppp_register_compressor);
3606	EXPORT_SYMBOL(ppp_unregister_compressor);
3607	MODULE_LICENSE("GPL");
3608	MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3609	MODULE_ALIAS_RTNL_LINK("ppp");
3610	MODULE_ALIAS("devname:ppp");
3611