1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic PPP layer for Linux.
4 *
5 * Copyright 1999-2002 Paul Mackerras.
6 *
7 * The generic PPP layer handles the PPP network interfaces, the
8 * /dev/ppp device, packet and VJ compression, and multilink.
9 * It talks to PPP `channels' via the interface defined in
10 * include/linux/ppp_channel.h. Channels provide the basic means for
11 * sending and receiving PPP frames on some kind of communications
12 * channel.
13 *
14 * Part of the code in this driver was inspired by the old async-only
15 * PPP driver, written by Michael Callahan and Al Longyear, and
16 * subsequently hacked by Paul Mackerras.
17 *
18 * ==FILEVERSION 20041108==
19 */
20
21#include <linux/module.h>
22#include <linux/kernel.h>
23#include <linux/sched/signal.h>
24#include <linux/kmod.h>
25#include <linux/init.h>
26#include <linux/list.h>
27#include <linux/idr.h>
28#include <linux/netdevice.h>
29#include <linux/poll.h>
30#include <linux/ppp_defs.h>
31#include <linux/filter.h>
32#include <linux/ppp-ioctl.h>
33#include <linux/ppp_channel.h>
34#include <linux/ppp-comp.h>
35#include <linux/skbuff.h>
36#include <linux/rculist.h>
37#include <linux/rtnetlink.h>
38#include <linux/if_arp.h>
39#include <linux/ip.h>
40#include <linux/tcp.h>
41#include <linux/spinlock.h>
42#include <linux/rwsem.h>
43#include <linux/stddef.h>
44#include <linux/device.h>
45#include <linux/mutex.h>
46#include <linux/slab.h>
47#include <linux/file.h>
48#include <linux/unaligned.h>
49#include <net/netdev_lock.h>
50#include <net/slhc_vj.h>
51#include <linux/atomic.h>
52#include <linux/refcount.h>
53
54#include <linux/nsproxy.h>
55#include <net/net_namespace.h>
56#include <net/netns/generic.h>
57
58#define PPP_VERSION "2.4.2"
59
60/*
61 * Network protocols we support.
62 */
63#define NP_IP 0 /* Internet Protocol V4 */
64#define NP_IPV6 1 /* Internet Protocol V6 */
65#define NP_IPX 2 /* IPX protocol */
66#define NP_AT 3 /* Appletalk protocol */
67#define NP_MPLS_UC 4 /* MPLS unicast */
68#define NP_MPLS_MC 5 /* MPLS multicast */
69#define NUM_NP 6 /* Number of NPs. */
70
71#define MPHDRLEN 6 /* multilink protocol header length */
72#define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
73
74#define PPP_PROTO_LEN 2
75#define PPP_LCP_HDRLEN 4
76
77/* The filter instructions generated by libpcap are constructed
78 * assuming a four-byte PPP header on each packet, where the last
79 * 2 bytes are the protocol field defined in the RFC and the first
80 * byte of the first 2 bytes indicates the direction.
81 * The second byte is currently unused, but we still need to initialize
82 * it to prevent crafted BPF programs from reading them which would
83 * cause reading of uninitialized data.
84 */
85#define PPP_FILTER_OUTBOUND_TAG 0x0100
86#define PPP_FILTER_INBOUND_TAG 0x0000
87
88/*
89 * An instance of /dev/ppp can be associated with either a ppp
90 * interface unit or a ppp channel. In both cases, file->private_data
91 * points to one of these.
92 */
93struct ppp_file {
94 enum {
95 INTERFACE=1, CHANNEL
96 } kind;
97 struct sk_buff_head xq; /* pppd transmit queue */
98 struct sk_buff_head rq; /* receive queue for pppd */
99 wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
100 refcount_t refcnt; /* # refs (incl /dev/ppp attached) */
101 int hdrlen; /* space to leave for headers */
102 int index; /* interface unit / channel number */
103 int dead; /* unit/channel has been shut down */
104};
105
106#define PF_TO_X(pf, X) container_of(pf, X, file)
107
108#define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
109#define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
110
111struct ppp_xmit_recursion {
112 struct task_struct *owner;
113 local_lock_t bh_lock;
114};
115
116/*
117 * Data structure describing one ppp unit.
118 * A ppp unit corresponds to a ppp network interface device
119 * and represents a multilink bundle.
120 * It can have 0 or more ppp channels connected to it.
121 */
122struct ppp {
123 struct ppp_file file; /* stuff for read/write/poll 0 */
124 struct file *owner; /* file that owns this unit 48 */
125 struct list_head channels; /* list of attached channels 4c */
126 int n_channels; /* how many channels are attached 54 */
127 spinlock_t rlock; /* lock for receive side 58 */
128 spinlock_t wlock; /* lock for transmit side 5c */
129 struct ppp_xmit_recursion __percpu *xmit_recursion; /* xmit recursion detect */
130 int mru; /* max receive unit 60 */
131 unsigned int flags; /* control bits 64 */
132 unsigned int xstate; /* transmit state bits 68 */
133 unsigned int rstate; /* receive state bits 6c */
134 int debug; /* debug flags 70 */
135 struct slcompress *vj; /* state for VJ header compression */
136 enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
137 struct sk_buff *xmit_pending; /* a packet ready to go out 88 */
138 struct compressor *xcomp; /* transmit packet compressor 8c */
139 void *xc_state; /* its internal state 90 */
140 struct compressor *rcomp; /* receive decompressor 94 */
141 void *rc_state; /* its internal state 98 */
142 unsigned long last_xmit; /* jiffies when last pkt sent 9c */
143 unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
144 struct net_device *dev; /* network interface device a4 */
145 int closing; /* is device closing down? a8 */
146#ifdef CONFIG_PPP_MULTILINK
147 int nxchan; /* next channel to send something on */
148 u32 nxseq; /* next sequence number to send */
149 int mrru; /* MP: max reconst. receive unit */
150 u32 nextseq; /* MP: seq no of next packet */
151 u32 minseq; /* MP: min of most recent seqnos */
152 struct sk_buff_head mrq; /* MP: receive reconstruction queue */
153#endif /* CONFIG_PPP_MULTILINK */
154#ifdef CONFIG_PPP_FILTER
155 struct bpf_prog *pass_filter; /* filter for packets to pass */
156 struct bpf_prog *active_filter; /* filter for pkts to reset idle */
157#endif /* CONFIG_PPP_FILTER */
158 struct net *ppp_net; /* the net we belong to */
159};
160
161/*
162 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
163 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
164 * SC_MUST_COMP
165 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
166 * Bits in xstate: SC_COMP_RUN
167 */
168#define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
169 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
170 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
171
172/*
173 * Private data structure for each channel.
174 * This includes the data structure used for multilink.
175 */
176struct channel {
177 struct ppp_file file; /* stuff for read/write/poll */
178 struct list_head list; /* link in all/new_channels list */
179 struct ppp_channel *chan; /* public channel data structure */
180 struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */
181 spinlock_t downl; /* protects `chan', file.xq dequeue */
182 struct ppp __rcu *ppp; /* ppp unit we're connected to */
183 struct net *chan_net; /* the net channel belongs to */
184 netns_tracker ns_tracker;
185 struct list_head clist; /* link in list of channels per unit */
186 spinlock_t upl; /* protects `ppp' and 'bridge' */
187 struct channel __rcu *bridge; /* "bridged" ppp channel */
188#ifdef CONFIG_PPP_MULTILINK
189 u8 avail; /* flag used in multilink stuff */
190 u8 had_frag; /* >= 1 fragments have been sent */
191 u32 lastseq; /* MP: last sequence # received */
192 int speed; /* speed of the corresponding ppp channel*/
193#endif /* CONFIG_PPP_MULTILINK */
194};
195
196struct ppp_config {
197 struct file *file;
198 s32 unit;
199 bool ifname_is_set;
200};
201
202/*
203 * SMP locking issues:
204 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
205 * list and the ppp.n_channels field, you need to take both locks
206 * before you modify them.
207 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
208 * channel.downl.
209 */
210
211static DEFINE_MUTEX(ppp_mutex);
212static atomic_t ppp_unit_count = ATOMIC_INIT(0);
213static atomic_t channel_count = ATOMIC_INIT(0);
214
215/* per-net private data for this module */
216static unsigned int ppp_net_id __read_mostly;
217struct ppp_net {
218 /* units to ppp mapping */
219 struct idr units_idr;
220
221 /*
222 * all_ppp_mutex protects the units_idr mapping.
223 * It also ensures that finding a ppp unit in the units_idr
224 * map and updating its file.refcnt field is atomic.
225 */
226 struct mutex all_ppp_mutex;
227
228 /* channels */
229 struct list_head all_channels;
230 struct list_head new_channels;
231 int last_channel_index;
232
233 /*
234 * all_channels_lock protects all_channels and
235 * last_channel_index, and the atomicity of find
236 * a channel and updating its file.refcnt field.
237 */
238 spinlock_t all_channels_lock;
239};
240
241/* Get the PPP protocol number from a skb */
242#define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
243
244/* We limit the length of ppp->file.rq to this (arbitrary) value */
245#define PPP_MAX_RQLEN 32
246
247/*
248 * Maximum number of multilink fragments queued up.
249 * This has to be large enough to cope with the maximum latency of
250 * the slowest channel relative to the others. Strictly it should
251 * depend on the number of channels and their characteristics.
252 */
253#define PPP_MP_MAX_QLEN 128
254
255/* Multilink header bits. */
256#define B 0x80 /* this fragment begins a packet */
257#define E 0x40 /* this fragment ends a packet */
258
259/* Compare multilink sequence numbers (assumed to be 32 bits wide) */
260#define seq_before(a, b) ((s32)((a) - (b)) < 0)
261#define seq_after(a, b) ((s32)((a) - (b)) > 0)
262
263/* Prototypes. */
264static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
265 struct file *file, unsigned int cmd, unsigned long arg);
266static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
267static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
268static void ppp_push(struct ppp *ppp);
269static void ppp_channel_push(struct channel *pch);
270static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
271 struct channel *pch);
272static void ppp_receive_error(struct ppp *ppp);
273static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
274static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
275 struct sk_buff *skb);
276#ifdef CONFIG_PPP_MULTILINK
277static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
278 struct channel *pch);
279static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
280static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
281static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
282#endif /* CONFIG_PPP_MULTILINK */
283static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
284static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
285static void ppp_ccp_closed(struct ppp *ppp);
286static struct compressor *find_compressor(int type);
287static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
288static int ppp_create_interface(struct net *net, struct file *file, int *unit);
289static void init_ppp_file(struct ppp_file *pf, int kind);
290static void ppp_destroy_interface(struct ppp *ppp);
291static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
292static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
293static int ppp_connect_channel(struct channel *pch, int unit);
294static int ppp_disconnect_channel(struct channel *pch);
295static void ppp_destroy_channel(struct channel *pch);
296static int unit_get(struct idr *p, void *ptr, int min);
297static int unit_set(struct idr *p, void *ptr, int n);
298static void unit_put(struct idr *p, int n);
299static void *unit_find(struct idr *p, int n);
300static void ppp_setup(struct net_device *dev);
301
302static const struct net_device_ops ppp_netdev_ops;
303
304static const struct class ppp_class = {
305 .name = "ppp",
306};
307
308/* per net-namespace data */
309static inline struct ppp_net *ppp_pernet(struct net *net)
310{
311 return net_generic(net, id: ppp_net_id);
312}
313
314/* Translates a PPP protocol number to a NP index (NP == network protocol) */
315static inline int proto_to_npindex(int proto)
316{
317 switch (proto) {
318 case PPP_IP:
319 return NP_IP;
320 case PPP_IPV6:
321 return NP_IPV6;
322 case PPP_IPX:
323 return NP_IPX;
324 case PPP_AT:
325 return NP_AT;
326 case PPP_MPLS_UC:
327 return NP_MPLS_UC;
328 case PPP_MPLS_MC:
329 return NP_MPLS_MC;
330 }
331 return -EINVAL;
332}
333
334/* Translates an NP index into a PPP protocol number */
335static const int npindex_to_proto[NUM_NP] = {
336 PPP_IP,
337 PPP_IPV6,
338 PPP_IPX,
339 PPP_AT,
340 PPP_MPLS_UC,
341 PPP_MPLS_MC,
342};
343
344/* Translates an ethertype into an NP index */
345static inline int ethertype_to_npindex(int ethertype)
346{
347 switch (ethertype) {
348 case ETH_P_IP:
349 return NP_IP;
350 case ETH_P_IPV6:
351 return NP_IPV6;
352 case ETH_P_IPX:
353 return NP_IPX;
354 case ETH_P_PPPTALK:
355 case ETH_P_ATALK:
356 return NP_AT;
357 case ETH_P_MPLS_UC:
358 return NP_MPLS_UC;
359 case ETH_P_MPLS_MC:
360 return NP_MPLS_MC;
361 }
362 return -1;
363}
364
365/* Translates an NP index into an ethertype */
366static const int npindex_to_ethertype[NUM_NP] = {
367 ETH_P_IP,
368 ETH_P_IPV6,
369 ETH_P_IPX,
370 ETH_P_PPPTALK,
371 ETH_P_MPLS_UC,
372 ETH_P_MPLS_MC,
373};
374
375/*
376 * Locking shorthand.
377 */
378#define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
379#define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
380#define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
381#define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
382#define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
383 ppp_recv_lock(ppp); } while (0)
384#define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
385 ppp_xmit_unlock(ppp); } while (0)
386
387/*
388 * /dev/ppp device routines.
389 * The /dev/ppp device is used by pppd to control the ppp unit.
390 * It supports the read, write, ioctl and poll functions.
391 * Open instances of /dev/ppp can be in one of three states:
392 * unattached, attached to a ppp unit, or attached to a ppp channel.
393 */
394static int ppp_open(struct inode *inode, struct file *file)
395{
396 /*
397 * This could (should?) be enforced by the permissions on /dev/ppp.
398 */
399 if (!ns_capable(ns: file->f_cred->user_ns, CAP_NET_ADMIN))
400 return -EPERM;
401 return 0;
402}
403
404static int ppp_release(struct inode *unused, struct file *file)
405{
406 struct ppp_file *pf = file->private_data;
407 struct ppp *ppp;
408
409 if (pf) {
410 file->private_data = NULL;
411 if (pf->kind == INTERFACE) {
412 ppp = PF_TO_PPP(pf);
413 rtnl_lock();
414 if (file == ppp->owner)
415 unregister_netdevice(dev: ppp->dev);
416 rtnl_unlock();
417 }
418 if (refcount_dec_and_test(r: &pf->refcnt)) {
419 switch (pf->kind) {
420 case INTERFACE:
421 ppp_destroy_interface(PF_TO_PPP(pf));
422 break;
423 case CHANNEL:
424 ppp_destroy_channel(PF_TO_CHANNEL(pf));
425 break;
426 }
427 }
428 }
429 return 0;
430}
431
432static ssize_t ppp_read(struct file *file, char __user *buf,
433 size_t count, loff_t *ppos)
434{
435 struct ppp_file *pf = file->private_data;
436 DECLARE_WAITQUEUE(wait, current);
437 ssize_t ret;
438 struct sk_buff *skb = NULL;
439 struct iovec iov;
440 struct iov_iter to;
441
442 ret = count;
443
444 if (!pf)
445 return -ENXIO;
446 add_wait_queue(wq_head: &pf->rwait, wq_entry: &wait);
447 for (;;) {
448 set_current_state(TASK_INTERRUPTIBLE);
449 skb = skb_dequeue(list: &pf->rq);
450 if (skb)
451 break;
452 ret = 0;
453 if (pf->dead)
454 break;
455 if (pf->kind == INTERFACE) {
456 /*
457 * Return 0 (EOF) on an interface that has no
458 * channels connected, unless it is looping
459 * network traffic (demand mode).
460 */
461 struct ppp *ppp = PF_TO_PPP(pf);
462
463 ppp_recv_lock(ppp);
464 if (ppp->n_channels == 0 &&
465 (ppp->flags & SC_LOOP_TRAFFIC) == 0) {
466 ppp_recv_unlock(ppp);
467 break;
468 }
469 ppp_recv_unlock(ppp);
470 }
471 ret = -EAGAIN;
472 if (file->f_flags & O_NONBLOCK)
473 break;
474 ret = -ERESTARTSYS;
475 if (signal_pending(current))
476 break;
477 schedule();
478 }
479 set_current_state(TASK_RUNNING);
480 remove_wait_queue(wq_head: &pf->rwait, wq_entry: &wait);
481
482 if (!skb)
483 goto out;
484
485 ret = -EOVERFLOW;
486 if (skb->len > count)
487 goto outf;
488 ret = -EFAULT;
489 iov.iov_base = buf;
490 iov.iov_len = count;
491 iov_iter_init(i: &to, ITER_DEST, iov: &iov, nr_segs: 1, count);
492 if (skb_copy_datagram_iter(from: skb, offset: 0, to: &to, size: skb->len))
493 goto outf;
494 ret = skb->len;
495
496 outf:
497 kfree_skb(skb);
498 out:
499 return ret;
500}
501
502static bool ppp_check_packet(struct sk_buff *skb, size_t count)
503{
504 /* LCP packets must include LCP header which 4 bytes long:
505 * 1-byte code, 1-byte identifier, and 2-byte length.
506 */
507 return get_unaligned_be16(p: skb->data) != PPP_LCP ||
508 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
509}
510
511static ssize_t ppp_write(struct file *file, const char __user *buf,
512 size_t count, loff_t *ppos)
513{
514 struct ppp_file *pf = file->private_data;
515 struct sk_buff *skb;
516 ssize_t ret;
517
518 if (!pf)
519 return -ENXIO;
520 /* All PPP packets should start with the 2-byte protocol */
521 if (count < PPP_PROTO_LEN)
522 return -EINVAL;
523 ret = -ENOMEM;
524 skb = alloc_skb(size: count + pf->hdrlen, GFP_KERNEL);
525 if (!skb)
526 goto out;
527 skb_reserve(skb, len: pf->hdrlen);
528 ret = -EFAULT;
529 if (copy_from_user(to: skb_put(skb, len: count), from: buf, n: count)) {
530 kfree_skb(skb);
531 goto out;
532 }
533 ret = -EINVAL;
534 if (unlikely(!ppp_check_packet(skb, count))) {
535 kfree_skb(skb);
536 goto out;
537 }
538
539 switch (pf->kind) {
540 case INTERFACE:
541 ppp_xmit_process(PF_TO_PPP(pf), skb);
542 break;
543 case CHANNEL:
544 skb_queue_tail(list: &pf->xq, newsk: skb);
545 ppp_channel_push(PF_TO_CHANNEL(pf));
546 break;
547 }
548
549 ret = count;
550
551 out:
552 return ret;
553}
554
555/* No kernel lock - fine */
556static __poll_t ppp_poll(struct file *file, poll_table *wait)
557{
558 struct ppp_file *pf = file->private_data;
559 __poll_t mask;
560
561 if (!pf)
562 return 0;
563 poll_wait(filp: file, wait_address: &pf->rwait, p: wait);
564 mask = EPOLLOUT | EPOLLWRNORM;
565 if (skb_peek(list_: &pf->rq))
566 mask |= EPOLLIN | EPOLLRDNORM;
567 if (pf->dead)
568 mask |= EPOLLHUP;
569 else if (pf->kind == INTERFACE) {
570 /* see comment in ppp_read */
571 struct ppp *ppp = PF_TO_PPP(pf);
572
573 ppp_recv_lock(ppp);
574 if (ppp->n_channels == 0 &&
575 (ppp->flags & SC_LOOP_TRAFFIC) == 0)
576 mask |= EPOLLIN | EPOLLRDNORM;
577 ppp_recv_unlock(ppp);
578 }
579
580 return mask;
581}
582
583#ifdef CONFIG_PPP_FILTER
584static struct bpf_prog *get_filter(struct sock_fprog *uprog)
585{
586 struct sock_fprog_kern fprog;
587 struct bpf_prog *res = NULL;
588 int err;
589
590 if (!uprog->len)
591 return NULL;
592
593 /* uprog->len is unsigned short, so no overflow here */
594 fprog.len = uprog->len;
595 fprog.filter = memdup_array_user(src: uprog->filter,
596 n: uprog->len, size: sizeof(struct sock_filter));
597 if (IS_ERR(ptr: fprog.filter))
598 return ERR_CAST(ptr: fprog.filter);
599
600 err = bpf_prog_create(pfp: &res, fprog: &fprog);
601 kfree(objp: fprog.filter);
602
603 return err ? ERR_PTR(error: err) : res;
604}
605
606static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
607{
608 struct sock_fprog uprog;
609
610 if (copy_from_user(to: &uprog, from: p, n: sizeof(struct sock_fprog)))
611 return ERR_PTR(error: -EFAULT);
612 return get_filter(uprog: &uprog);
613}
614
615#ifdef CONFIG_COMPAT
616struct sock_fprog32 {
617 unsigned short len;
618 compat_caddr_t filter;
619};
620
621#define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32)
622#define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32)
623
624static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
625{
626 struct sock_fprog32 uprog32;
627 struct sock_fprog uprog;
628
629 if (copy_from_user(to: &uprog32, from: p, n: sizeof(struct sock_fprog32)))
630 return ERR_PTR(error: -EFAULT);
631 uprog.len = uprog32.len;
632 uprog.filter = compat_ptr(uptr: uprog32.filter);
633 return get_filter(uprog: &uprog);
634}
635#endif
636#endif
637
638/* Bridge one PPP channel to another.
639 * When two channels are bridged, ppp_input on one channel is redirected to
640 * the other's ops->start_xmit handler.
641 * In order to safely bridge channels we must reject channels which are already
642 * part of a bridge instance, or which form part of an existing unit.
643 * Once successfully bridged, each channel holds a reference on the other
644 * to prevent it being freed while the bridge is extant.
645 */
646static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
647{
648 spin_lock(lock: &pch->upl);
649 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
650 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
651 spin_unlock(lock: &pch->upl);
652 return -EALREADY;
653 }
654 refcount_inc(r: &pchb->file.refcnt);
655 rcu_assign_pointer(pch->bridge, pchb);
656 spin_unlock(lock: &pch->upl);
657
658 spin_lock(lock: &pchb->upl);
659 if (rcu_dereference_protected(pchb->ppp, lockdep_is_held(&pchb->upl)) ||
660 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
661 spin_unlock(lock: &pchb->upl);
662 goto err_unset;
663 }
664 refcount_inc(r: &pch->file.refcnt);
665 rcu_assign_pointer(pchb->bridge, pch);
666 spin_unlock(lock: &pchb->upl);
667
668 return 0;
669
670err_unset:
671 spin_lock(lock: &pch->upl);
672 /* Re-read pch->bridge with upl held in case it was modified concurrently */
673 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
674 RCU_INIT_POINTER(pch->bridge, NULL);
675 spin_unlock(lock: &pch->upl);
676 synchronize_rcu();
677
678 if (pchb)
679 if (refcount_dec_and_test(r: &pchb->file.refcnt))
680 ppp_destroy_channel(pch: pchb);
681
682 return -EALREADY;
683}
684
685static int ppp_unbridge_channels(struct channel *pch)
686{
687 struct channel *pchb, *pchbb;
688
689 spin_lock(lock: &pch->upl);
690 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
691 if (!pchb) {
692 spin_unlock(lock: &pch->upl);
693 return -EINVAL;
694 }
695 RCU_INIT_POINTER(pch->bridge, NULL);
696 spin_unlock(lock: &pch->upl);
697
698 /* Only modify pchb if phcb->bridge points back to pch.
699 * If not, it implies that there has been a race unbridging (and possibly
700 * even rebridging) pchb. We should leave pchb alone to avoid either a
701 * refcount underflow, or breaking another established bridge instance.
702 */
703 spin_lock(lock: &pchb->upl);
704 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
705 if (pchbb == pch)
706 RCU_INIT_POINTER(pchb->bridge, NULL);
707 spin_unlock(lock: &pchb->upl);
708
709 synchronize_rcu();
710
711 if (pchbb == pch)
712 if (refcount_dec_and_test(r: &pch->file.refcnt))
713 ppp_destroy_channel(pch);
714
715 if (refcount_dec_and_test(r: &pchb->file.refcnt))
716 ppp_destroy_channel(pch: pchb);
717
718 return 0;
719}
720
721static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
722{
723 struct ppp_file *pf;
724 struct ppp *ppp;
725 int err = -EFAULT, val, val2, i;
726 struct ppp_idle32 idle32;
727 struct ppp_idle64 idle64;
728 struct npioctl npi;
729 int unit, cflags;
730 struct slcompress *vj;
731 void __user *argp = (void __user *)arg;
732 int __user *p = argp;
733
734 mutex_lock(&ppp_mutex);
735
736 pf = file->private_data;
737 if (!pf) {
738 err = ppp_unattached_ioctl(current->nsproxy->net_ns,
739 pf, file, cmd, arg);
740 goto out;
741 }
742
743 if (cmd == PPPIOCDETACH) {
744 /*
745 * PPPIOCDETACH is no longer supported as it was heavily broken,
746 * and is only known to have been used by pppd older than
747 * ppp-2.4.2 (released November 2003).
748 */
749 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n",
750 current->comm, current->pid);
751 err = -EINVAL;
752 goto out;
753 }
754
755 if (pf->kind == CHANNEL) {
756 struct channel *pch, *pchb;
757 struct ppp_channel *chan;
758 struct ppp_net *pn;
759
760 pch = PF_TO_CHANNEL(pf);
761
762 switch (cmd) {
763 case PPPIOCCONNECT:
764 if (get_user(unit, p))
765 break;
766 err = ppp_connect_channel(pch, unit);
767 break;
768
769 case PPPIOCDISCONN:
770 err = ppp_disconnect_channel(pch);
771 break;
772
773 case PPPIOCBRIDGECHAN:
774 if (get_user(unit, p))
775 break;
776 err = -ENXIO;
777 pn = ppp_pernet(current->nsproxy->net_ns);
778 spin_lock_bh(lock: &pn->all_channels_lock);
779 pchb = ppp_find_channel(pn, unit);
780 /* Hold a reference to prevent pchb being freed while
781 * we establish the bridge.
782 */
783 if (pchb)
784 refcount_inc(r: &pchb->file.refcnt);
785 spin_unlock_bh(lock: &pn->all_channels_lock);
786 if (!pchb)
787 break;
788 err = ppp_bridge_channels(pch, pchb);
789 /* Drop earlier refcount now bridge establishment is complete */
790 if (refcount_dec_and_test(r: &pchb->file.refcnt))
791 ppp_destroy_channel(pch: pchb);
792 break;
793
794 case PPPIOCUNBRIDGECHAN:
795 err = ppp_unbridge_channels(pch);
796 break;
797
798 default:
799 down_read(sem: &pch->chan_sem);
800 chan = pch->chan;
801 err = -ENOTTY;
802 if (chan && chan->ops->ioctl)
803 err = chan->ops->ioctl(chan, cmd, arg);
804 up_read(sem: &pch->chan_sem);
805 }
806 goto out;
807 }
808
809 if (pf->kind != INTERFACE) {
810 /* can't happen */
811 pr_err("PPP: not interface or channel??\n");
812 err = -EINVAL;
813 goto out;
814 }
815
816 ppp = PF_TO_PPP(pf);
817 switch (cmd) {
818 case PPPIOCSMRU:
819 if (get_user(val, p))
820 break;
821 ppp->mru = val;
822 err = 0;
823 break;
824
825 case PPPIOCSFLAGS:
826 if (get_user(val, p))
827 break;
828 ppp_lock(ppp);
829 cflags = ppp->flags & ~val;
830#ifdef CONFIG_PPP_MULTILINK
831 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK))
832 ppp->nextseq = 0;
833#endif
834 ppp->flags = val & SC_FLAG_BITS;
835 ppp_unlock(ppp);
836 if (cflags & SC_CCP_OPEN)
837 ppp_ccp_closed(ppp);
838 err = 0;
839 break;
840
841 case PPPIOCGFLAGS:
842 val = ppp->flags | ppp->xstate | ppp->rstate;
843 if (put_user(val, p))
844 break;
845 err = 0;
846 break;
847
848 case PPPIOCSCOMPRESS:
849 {
850 struct ppp_option_data data;
851 if (copy_from_user(to: &data, from: argp, n: sizeof(data)))
852 err = -EFAULT;
853 else
854 err = ppp_set_compress(ppp, data: &data);
855 break;
856 }
857 case PPPIOCGUNIT:
858 if (put_user(ppp->file.index, p))
859 break;
860 err = 0;
861 break;
862
863 case PPPIOCSDEBUG:
864 if (get_user(val, p))
865 break;
866 ppp->debug = val;
867 err = 0;
868 break;
869
870 case PPPIOCGDEBUG:
871 if (put_user(ppp->debug, p))
872 break;
873 err = 0;
874 break;
875
876 case PPPIOCGIDLE32:
877 idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
878 idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
879 if (copy_to_user(to: argp, from: &idle32, n: sizeof(idle32)))
880 break;
881 err = 0;
882 break;
883
884 case PPPIOCGIDLE64:
885 idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
886 idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
887 if (copy_to_user(to: argp, from: &idle64, n: sizeof(idle64)))
888 break;
889 err = 0;
890 break;
891
892 case PPPIOCSMAXCID:
893 if (get_user(val, p))
894 break;
895 val2 = 15;
896 if ((val >> 16) != 0) {
897 val2 = val >> 16;
898 val &= 0xffff;
899 }
900 vj = slhc_init(rslots: val2+1, tslots: val+1);
901 if (IS_ERR(ptr: vj)) {
902 err = PTR_ERR(ptr: vj);
903 break;
904 }
905 ppp_lock(ppp);
906 if (ppp->vj)
907 slhc_free(comp: ppp->vj);
908 ppp->vj = vj;
909 ppp_unlock(ppp);
910 err = 0;
911 break;
912
913 case PPPIOCGNPMODE:
914 case PPPIOCSNPMODE:
915 if (copy_from_user(to: &npi, from: argp, n: sizeof(npi)))
916 break;
917 err = proto_to_npindex(proto: npi.protocol);
918 if (err < 0)
919 break;
920 i = err;
921 if (cmd == PPPIOCGNPMODE) {
922 err = -EFAULT;
923 npi.mode = ppp->npmode[i];
924 if (copy_to_user(to: argp, from: &npi, n: sizeof(npi)))
925 break;
926 } else {
927 ppp->npmode[i] = npi.mode;
928 /* we may be able to transmit more packets now (??) */
929 netif_wake_queue(dev: ppp->dev);
930 }
931 err = 0;
932 break;
933
934#ifdef CONFIG_PPP_FILTER
935 case PPPIOCSPASS:
936 case PPPIOCSACTIVE:
937 {
938 struct bpf_prog *filter = ppp_get_filter(p: argp);
939 struct bpf_prog **which;
940
941 if (IS_ERR(ptr: filter)) {
942 err = PTR_ERR(ptr: filter);
943 break;
944 }
945 if (cmd == PPPIOCSPASS)
946 which = &ppp->pass_filter;
947 else
948 which = &ppp->active_filter;
949 ppp_lock(ppp);
950 if (*which)
951 bpf_prog_destroy(fp: *which);
952 *which = filter;
953 ppp_unlock(ppp);
954 err = 0;
955 break;
956 }
957#endif /* CONFIG_PPP_FILTER */
958
959#ifdef CONFIG_PPP_MULTILINK
960 case PPPIOCSMRRU:
961 if (get_user(val, p))
962 break;
963 ppp_recv_lock(ppp);
964 ppp->mrru = val;
965 ppp_recv_unlock(ppp);
966 err = 0;
967 break;
968#endif /* CONFIG_PPP_MULTILINK */
969
970 default:
971 err = -ENOTTY;
972 }
973
974out:
975 mutex_unlock(lock: &ppp_mutex);
976
977 return err;
978}
979
980#ifdef CONFIG_COMPAT
981struct ppp_option_data32 {
982 compat_uptr_t ptr;
983 u32 length;
984 compat_int_t transmit;
985};
986#define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32)
987
988static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
989{
990 struct ppp_file *pf;
991 int err = -ENOIOCTLCMD;
992 void __user *argp = (void __user *)arg;
993
994 mutex_lock(&ppp_mutex);
995
996 pf = file->private_data;
997 if (pf && pf->kind == INTERFACE) {
998 struct ppp *ppp = PF_TO_PPP(pf);
999 switch (cmd) {
1000#ifdef CONFIG_PPP_FILTER
1001 case PPPIOCSPASS32:
1002 case PPPIOCSACTIVE32:
1003 {
1004 struct bpf_prog *filter = compat_ppp_get_filter(p: argp);
1005 struct bpf_prog **which;
1006
1007 if (IS_ERR(ptr: filter)) {
1008 err = PTR_ERR(ptr: filter);
1009 break;
1010 }
1011 if (cmd == PPPIOCSPASS32)
1012 which = &ppp->pass_filter;
1013 else
1014 which = &ppp->active_filter;
1015 ppp_lock(ppp);
1016 if (*which)
1017 bpf_prog_destroy(fp: *which);
1018 *which = filter;
1019 ppp_unlock(ppp);
1020 err = 0;
1021 break;
1022 }
1023#endif /* CONFIG_PPP_FILTER */
1024 case PPPIOCSCOMPRESS32:
1025 {
1026 struct ppp_option_data32 data32;
1027 if (copy_from_user(to: &data32, from: argp, n: sizeof(data32))) {
1028 err = -EFAULT;
1029 } else {
1030 struct ppp_option_data data = {
1031 .ptr = compat_ptr(uptr: data32.ptr),
1032 .length = data32.length,
1033 .transmit = data32.transmit
1034 };
1035 err = ppp_set_compress(ppp, data: &data);
1036 }
1037 break;
1038 }
1039 }
1040 }
1041 mutex_unlock(lock: &ppp_mutex);
1042
1043 /* all other commands have compatible arguments */
1044 if (err == -ENOIOCTLCMD)
1045 err = ppp_ioctl(file, cmd, arg: (unsigned long)compat_ptr(uptr: arg));
1046
1047 return err;
1048}
1049#endif
1050
1051static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
1052 struct file *file, unsigned int cmd, unsigned long arg)
1053{
1054 int unit, err = -EFAULT;
1055 struct ppp *ppp;
1056 struct channel *chan;
1057 struct ppp_net *pn;
1058 int __user *p = (int __user *)arg;
1059
1060 switch (cmd) {
1061 case PPPIOCNEWUNIT:
1062 /* Create a new ppp unit */
1063 if (get_user(unit, p))
1064 break;
1065 err = ppp_create_interface(net, file, unit: &unit);
1066 if (err < 0)
1067 break;
1068
1069 err = -EFAULT;
1070 if (put_user(unit, p))
1071 break;
1072 err = 0;
1073 break;
1074
1075 case PPPIOCATTACH:
1076 /* Attach to an existing ppp unit */
1077 if (get_user(unit, p))
1078 break;
1079 err = -ENXIO;
1080 pn = ppp_pernet(net);
1081 mutex_lock(&pn->all_ppp_mutex);
1082 ppp = ppp_find_unit(pn, unit);
1083 if (ppp) {
1084 refcount_inc(r: &ppp->file.refcnt);
1085 file->private_data = &ppp->file;
1086 err = 0;
1087 }
1088 mutex_unlock(lock: &pn->all_ppp_mutex);
1089 break;
1090
1091 case PPPIOCATTCHAN:
1092 if (get_user(unit, p))
1093 break;
1094 err = -ENXIO;
1095 pn = ppp_pernet(net);
1096 spin_lock_bh(lock: &pn->all_channels_lock);
1097 chan = ppp_find_channel(pn, unit);
1098 if (chan) {
1099 refcount_inc(r: &chan->file.refcnt);
1100 file->private_data = &chan->file;
1101 err = 0;
1102 }
1103 spin_unlock_bh(lock: &pn->all_channels_lock);
1104 break;
1105
1106 default:
1107 err = -ENOTTY;
1108 }
1109
1110 return err;
1111}
1112
1113static const struct file_operations ppp_device_fops = {
1114 .owner = THIS_MODULE,
1115 .read = ppp_read,
1116 .write = ppp_write,
1117 .poll = ppp_poll,
1118 .unlocked_ioctl = ppp_ioctl,
1119#ifdef CONFIG_COMPAT
1120 .compat_ioctl = ppp_compat_ioctl,
1121#endif
1122 .open = ppp_open,
1123 .release = ppp_release,
1124 .llseek = noop_llseek,
1125};
1126
1127static void ppp_nl_dellink(struct net_device *dev, struct list_head *head);
1128
1129static __net_init int ppp_init_net(struct net *net)
1130{
1131 struct ppp_net *pn = net_generic(net, id: ppp_net_id);
1132
1133 idr_init(idr: &pn->units_idr);
1134 mutex_init(&pn->all_ppp_mutex);
1135
1136 INIT_LIST_HEAD(list: &pn->all_channels);
1137 INIT_LIST_HEAD(list: &pn->new_channels);
1138
1139 spin_lock_init(&pn->all_channels_lock);
1140
1141 return 0;
1142}
1143
1144static __net_exit void ppp_exit_rtnl_net(struct net *net,
1145 struct list_head *dev_to_kill)
1146{
1147 struct ppp_net *pn = net_generic(net, id: ppp_net_id);
1148 struct ppp *ppp;
1149 int id;
1150
1151 idr_for_each_entry(&pn->units_idr, ppp, id)
1152 ppp_nl_dellink(dev: ppp->dev, head: dev_to_kill);
1153}
1154
1155static __net_exit void ppp_exit_net(struct net *net)
1156{
1157 struct ppp_net *pn = net_generic(net, id: ppp_net_id);
1158
1159 mutex_destroy(lock: &pn->all_ppp_mutex);
1160 idr_destroy(&pn->units_idr);
1161 WARN_ON_ONCE(!list_empty(&pn->all_channels));
1162 WARN_ON_ONCE(!list_empty(&pn->new_channels));
1163}
1164
1165static struct pernet_operations ppp_net_ops = {
1166 .init = ppp_init_net,
1167 .exit_rtnl = ppp_exit_rtnl_net,
1168 .exit = ppp_exit_net,
1169 .id = &ppp_net_id,
1170 .size = sizeof(struct ppp_net),
1171};
1172
1173static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
1174{
1175 struct ppp_net *pn = ppp_pernet(net: ppp->ppp_net);
1176 int ret;
1177
1178 mutex_lock(&pn->all_ppp_mutex);
1179
1180 if (unit < 0) {
1181 ret = unit_get(p: &pn->units_idr, ptr: ppp, min: 0);
1182 if (ret < 0)
1183 goto err;
1184 if (!ifname_is_set) {
1185 while (1) {
1186 snprintf(buf: ppp->dev->name, IFNAMSIZ, fmt: "ppp%i", ret);
1187 if (!netdev_name_in_use(net: ppp->ppp_net, name: ppp->dev->name))
1188 break;
1189 unit_put(p: &pn->units_idr, n: ret);
1190 ret = unit_get(p: &pn->units_idr, ptr: ppp, min: ret + 1);
1191 if (ret < 0)
1192 goto err;
1193 }
1194 }
1195 } else {
1196 /* Caller asked for a specific unit number. Fail with -EEXIST
1197 * if unavailable. For backward compatibility, return -EEXIST
1198 * too if idr allocation fails; this makes pppd retry without
1199 * requesting a specific unit number.
1200 */
1201 if (unit_find(p: &pn->units_idr, n: unit)) {
1202 ret = -EEXIST;
1203 goto err;
1204 }
1205 ret = unit_set(p: &pn->units_idr, ptr: ppp, n: unit);
1206 if (ret < 0) {
1207 /* Rewrite error for backward compatibility */
1208 ret = -EEXIST;
1209 goto err;
1210 }
1211 }
1212 ppp->file.index = ret;
1213
1214 if (!ifname_is_set)
1215 snprintf(buf: ppp->dev->name, IFNAMSIZ, fmt: "ppp%i", ppp->file.index);
1216
1217 mutex_unlock(lock: &pn->all_ppp_mutex);
1218
1219 ret = register_netdevice(dev: ppp->dev);
1220 if (ret < 0)
1221 goto err_unit;
1222
1223 atomic_inc(v: &ppp_unit_count);
1224
1225 return 0;
1226
1227err_unit:
1228 mutex_lock(&pn->all_ppp_mutex);
1229 unit_put(p: &pn->units_idr, n: ppp->file.index);
1230err:
1231 mutex_unlock(lock: &pn->all_ppp_mutex);
1232
1233 return ret;
1234}
1235
1236static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
1237 const struct ppp_config *conf)
1238{
1239 struct ppp *ppp = netdev_priv(dev);
1240 int indx;
1241 int err;
1242 int cpu;
1243
1244 ppp->dev = dev;
1245 ppp->ppp_net = src_net;
1246 ppp->mru = PPP_MRU;
1247 ppp->owner = conf->file;
1248
1249 init_ppp_file(pf: &ppp->file, kind: INTERFACE);
1250 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
1251
1252 for (indx = 0; indx < NUM_NP; ++indx)
1253 ppp->npmode[indx] = NPMODE_PASS;
1254 INIT_LIST_HEAD(list: &ppp->channels);
1255 spin_lock_init(&ppp->rlock);
1256 spin_lock_init(&ppp->wlock);
1257
1258 ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion);
1259 if (!ppp->xmit_recursion) {
1260 err = -ENOMEM;
1261 goto err1;
1262 }
1263 for_each_possible_cpu(cpu) {
1264 struct ppp_xmit_recursion *xmit_recursion;
1265
1266 xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu);
1267 xmit_recursion->owner = NULL;
1268 local_lock_init(&xmit_recursion->bh_lock);
1269 }
1270
1271#ifdef CONFIG_PPP_MULTILINK
1272 ppp->minseq = -1;
1273 skb_queue_head_init(list: &ppp->mrq);
1274#endif /* CONFIG_PPP_MULTILINK */
1275#ifdef CONFIG_PPP_FILTER
1276 ppp->pass_filter = NULL;
1277 ppp->active_filter = NULL;
1278#endif /* CONFIG_PPP_FILTER */
1279
1280 err = ppp_unit_register(ppp, unit: conf->unit, ifname_is_set: conf->ifname_is_set);
1281 if (err < 0)
1282 goto err2;
1283
1284 conf->file->private_data = &ppp->file;
1285
1286 return 0;
1287err2:
1288 free_percpu(pdata: ppp->xmit_recursion);
1289err1:
1290 return err;
1291}
1292
1293static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = {
1294 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 },
1295};
1296
1297static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
1298 struct netlink_ext_ack *extack)
1299{
1300 if (!data)
1301 return -EINVAL;
1302
1303 if (!data[IFLA_PPP_DEV_FD])
1304 return -EINVAL;
1305 if (nla_get_s32(nla: data[IFLA_PPP_DEV_FD]) < 0)
1306 return -EBADF;
1307
1308 return 0;
1309}
1310
1311static int ppp_nl_newlink(struct net_device *dev,
1312 struct rtnl_newlink_params *params,
1313 struct netlink_ext_ack *extack)
1314{
1315 struct net *link_net = rtnl_newlink_link_net(p: params);
1316 struct nlattr **data = params->data;
1317 struct nlattr **tb = params->tb;
1318 struct ppp_config conf = {
1319 .unit = -1,
1320 .ifname_is_set = true,
1321 };
1322 struct file *file;
1323 int err;
1324
1325 file = fget(fd: nla_get_s32(nla: data[IFLA_PPP_DEV_FD]));
1326 if (!file)
1327 return -EBADF;
1328
1329 /* rtnl_lock is already held here, but ppp_create_interface() locks
1330 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids
1331 * possible deadlock due to lock order inversion, at the cost of
1332 * pushing the problem back to userspace.
1333 */
1334 if (!mutex_trylock(&ppp_mutex)) {
1335 err = -EBUSY;
1336 goto out;
1337 }
1338
1339 if (file->f_op != &ppp_device_fops || file->private_data) {
1340 err = -EBADF;
1341 goto out_unlock;
1342 }
1343
1344 conf.file = file;
1345
1346 /* Don't use device name generated by the rtnetlink layer when ifname
1347 * isn't specified. Let ppp_dev_configure() set the device name using
1348 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
1349 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
1350 */
1351 if (!tb[IFLA_IFNAME] || !nla_len(nla: tb[IFLA_IFNAME]) || !*(char *)nla_data(nla: tb[IFLA_IFNAME]))
1352 conf.ifname_is_set = false;
1353
1354 err = ppp_dev_configure(src_net: link_net, dev, conf: &conf);
1355
1356out_unlock:
1357 mutex_unlock(lock: &ppp_mutex);
1358out:
1359 fput(file);
1360
1361 return err;
1362}
1363
1364static void ppp_nl_dellink(struct net_device *dev, struct list_head *head)
1365{
1366 unregister_netdevice_queue(dev, head);
1367}
1368
1369static size_t ppp_nl_get_size(const struct net_device *dev)
1370{
1371 return 0;
1372}
1373
1374static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1375{
1376 return 0;
1377}
1378
1379static struct net *ppp_nl_get_link_net(const struct net_device *dev)
1380{
1381 struct ppp *ppp = netdev_priv(dev);
1382
1383 return READ_ONCE(ppp->ppp_net);
1384}
1385
1386static struct rtnl_link_ops ppp_link_ops __read_mostly = {
1387 .kind = "ppp",
1388 .maxtype = IFLA_PPP_MAX,
1389 .policy = ppp_nl_policy,
1390 .priv_size = sizeof(struct ppp),
1391 .setup = ppp_setup,
1392 .validate = ppp_nl_validate,
1393 .newlink = ppp_nl_newlink,
1394 .dellink = ppp_nl_dellink,
1395 .get_size = ppp_nl_get_size,
1396 .fill_info = ppp_nl_fill_info,
1397 .get_link_net = ppp_nl_get_link_net,
1398};
1399
1400#define PPP_MAJOR 108
1401
1402/* Called at boot time if ppp is compiled into the kernel,
1403 or at module load time (from init_module) if compiled as a module. */
1404static int __init ppp_init(void)
1405{
1406 int err;
1407
1408 pr_info("PPP generic driver version " PPP_VERSION "\n");
1409
1410 err = register_pernet_device(&ppp_net_ops);
1411 if (err) {
1412 pr_err("failed to register PPP pernet device (%d)\n", err);
1413 goto out;
1414 }
1415
1416 err = register_chrdev(PPP_MAJOR, name: "ppp", fops: &ppp_device_fops);
1417 if (err) {
1418 pr_err("failed to register PPP device (%d)\n", err);
1419 goto out_net;
1420 }
1421
1422 err = class_register(class: &ppp_class);
1423 if (err)
1424 goto out_chrdev;
1425
1426 err = rtnl_link_register(ops: &ppp_link_ops);
1427 if (err) {
1428 pr_err("failed to register rtnetlink PPP handler\n");
1429 goto out_class;
1430 }
1431
1432 /* not a big deal if we fail here :-) */
1433 device_create(cls: &ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, fmt: "ppp");
1434
1435 return 0;
1436
1437out_class:
1438 class_unregister(class: &ppp_class);
1439out_chrdev:
1440 unregister_chrdev(PPP_MAJOR, name: "ppp");
1441out_net:
1442 unregister_pernet_device(&ppp_net_ops);
1443out:
1444 return err;
1445}
1446
1447/*
1448 * Network interface unit routines.
1449 */
1450static netdev_tx_t
1451ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
1452{
1453 struct ppp *ppp = netdev_priv(dev);
1454 int npi, proto;
1455 unsigned char *pp;
1456
1457 npi = ethertype_to_npindex(ntohs(skb->protocol));
1458 if (npi < 0)
1459 goto outf;
1460
1461 /* Drop, accept or reject the packet */
1462 switch (ppp->npmode[npi]) {
1463 case NPMODE_PASS:
1464 break;
1465 case NPMODE_QUEUE:
1466 /* it would be nice to have a way to tell the network
1467 system to queue this one up for later. */
1468 goto outf;
1469 case NPMODE_DROP:
1470 case NPMODE_ERROR:
1471 goto outf;
1472 }
1473
1474 /* Put the 2-byte PPP protocol number on the front,
1475 making sure there is room for the address and control fields. */
1476 if (skb_cow_head(skb, PPP_HDRLEN))
1477 goto outf;
1478
1479 pp = skb_push(skb, len: 2);
1480 proto = npindex_to_proto[npi];
1481 put_unaligned_be16(val: proto, p: pp);
1482
1483 skb_scrub_packet(skb, xnet: !net_eq(net1: ppp->ppp_net, net2: dev_net(dev)));
1484 ppp_xmit_process(ppp, skb);
1485
1486 return NETDEV_TX_OK;
1487
1488 outf:
1489 kfree_skb(skb);
1490 ++dev->stats.tx_dropped;
1491 return NETDEV_TX_OK;
1492}
1493
1494static int
1495ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1496 void __user *addr, int cmd)
1497{
1498 struct ppp *ppp = netdev_priv(dev);
1499 int err = -EFAULT;
1500 struct ppp_stats stats;
1501 struct ppp_comp_stats cstats;
1502 char *vers;
1503
1504 switch (cmd) {
1505 case SIOCGPPPSTATS:
1506 ppp_get_stats(ppp, st: &stats);
1507 if (copy_to_user(to: addr, from: &stats, n: sizeof(stats)))
1508 break;
1509 err = 0;
1510 break;
1511
1512 case SIOCGPPPCSTATS:
1513 memset(&cstats, 0, sizeof(cstats));
1514 if (ppp->xc_state)
1515 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1516 if (ppp->rc_state)
1517 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1518 if (copy_to_user(to: addr, from: &cstats, n: sizeof(cstats)))
1519 break;
1520 err = 0;
1521 break;
1522
1523 case SIOCGPPPVER:
1524 vers = PPP_VERSION;
1525 if (copy_to_user(to: addr, from: vers, strlen(vers) + 1))
1526 break;
1527 err = 0;
1528 break;
1529
1530 default:
1531 err = -EINVAL;
1532 }
1533
1534 return err;
1535}
1536
1537static void
1538ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
1539{
1540 stats64->rx_errors = dev->stats.rx_errors;
1541 stats64->tx_errors = dev->stats.tx_errors;
1542 stats64->rx_dropped = dev->stats.rx_dropped;
1543 stats64->tx_dropped = dev->stats.tx_dropped;
1544 stats64->rx_length_errors = dev->stats.rx_length_errors;
1545 dev_fetch_sw_netstats(s: stats64, netstats: dev->tstats);
1546}
1547
1548static int ppp_dev_init(struct net_device *dev)
1549{
1550 struct ppp *ppp;
1551
1552 netdev_lockdep_set_classes(dev);
1553
1554 ppp = netdev_priv(dev);
1555 /* Let the netdevice take a reference on the ppp file. This ensures
1556 * that ppp_destroy_interface() won't run before the device gets
1557 * unregistered.
1558 */
1559 refcount_inc(r: &ppp->file.refcnt);
1560
1561 return 0;
1562}
1563
1564static void ppp_dev_uninit(struct net_device *dev)
1565{
1566 struct ppp *ppp = netdev_priv(dev);
1567 struct ppp_net *pn = ppp_pernet(net: ppp->ppp_net);
1568
1569 ppp_lock(ppp);
1570 ppp->closing = 1;
1571 ppp_unlock(ppp);
1572
1573 mutex_lock(&pn->all_ppp_mutex);
1574 unit_put(p: &pn->units_idr, n: ppp->file.index);
1575 mutex_unlock(lock: &pn->all_ppp_mutex);
1576
1577 ppp->owner = NULL;
1578
1579 ppp->file.dead = 1;
1580 wake_up_interruptible(&ppp->file.rwait);
1581}
1582
1583static void ppp_dev_priv_destructor(struct net_device *dev)
1584{
1585 struct ppp *ppp;
1586
1587 ppp = netdev_priv(dev);
1588 if (refcount_dec_and_test(r: &ppp->file.refcnt))
1589 ppp_destroy_interface(ppp);
1590}
1591
1592static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
1593 struct net_device_path *path)
1594{
1595 struct ppp *ppp = netdev_priv(dev: ctx->dev);
1596 struct ppp_channel *chan;
1597 struct channel *pch;
1598
1599 if (ppp->flags & SC_MULTILINK)
1600 return -EOPNOTSUPP;
1601
1602 pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist);
1603 if (!pch)
1604 return -ENODEV;
1605
1606 chan = READ_ONCE(pch->chan);
1607 if (!chan)
1608 return -ENODEV;
1609
1610 if (!chan->ops->fill_forward_path)
1611 return -EOPNOTSUPP;
1612
1613 return chan->ops->fill_forward_path(ctx, path, chan);
1614}
1615
1616static const struct net_device_ops ppp_netdev_ops = {
1617 .ndo_init = ppp_dev_init,
1618 .ndo_uninit = ppp_dev_uninit,
1619 .ndo_start_xmit = ppp_start_xmit,
1620 .ndo_siocdevprivate = ppp_net_siocdevprivate,
1621 .ndo_get_stats64 = ppp_get_stats64,
1622 .ndo_fill_forward_path = ppp_fill_forward_path,
1623};
1624
1625static const struct device_type ppp_type = {
1626 .name = "ppp",
1627};
1628
1629static void ppp_setup(struct net_device *dev)
1630{
1631 dev->netdev_ops = &ppp_netdev_ops;
1632 SET_NETDEV_DEVTYPE(dev, &ppp_type);
1633
1634 dev->lltx = true;
1635
1636 dev->hard_header_len = PPP_HDRLEN;
1637 dev->mtu = PPP_MRU;
1638 dev->addr_len = 0;
1639 dev->tx_queue_len = 3;
1640 dev->type = ARPHRD_PPP;
1641 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1642 dev->priv_destructor = ppp_dev_priv_destructor;
1643 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1644 netif_keep_dst(dev);
1645}
1646
1647/*
1648 * Transmit-side routines.
1649 */
1650
1651/* Called to do any work queued up on the transmit side that can now be done */
1652static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1653{
1654 ppp_xmit_lock(ppp);
1655 if (!ppp->closing) {
1656 ppp_push(ppp);
1657
1658 if (skb)
1659 skb_queue_tail(list: &ppp->file.xq, newsk: skb);
1660 while (!ppp->xmit_pending &&
1661 (skb = skb_dequeue(list: &ppp->file.xq)))
1662 ppp_send_frame(ppp, skb);
1663 /* If there's no work left to do, tell the core net
1664 code that we can accept some more. */
1665 if (!ppp->xmit_pending && !skb_peek(list_: &ppp->file.xq))
1666 netif_wake_queue(dev: ppp->dev);
1667 else
1668 netif_stop_queue(dev: ppp->dev);
1669 } else {
1670 kfree_skb(skb);
1671 }
1672 ppp_xmit_unlock(ppp);
1673}
1674
1675static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
1676{
1677 struct ppp_xmit_recursion *xmit_recursion;
1678
1679 local_bh_disable();
1680
1681 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
1682 if (xmit_recursion->owner == current)
1683 goto err;
1684 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
1685 xmit_recursion->owner = current;
1686
1687 __ppp_xmit_process(ppp, skb);
1688
1689 xmit_recursion->owner = NULL;
1690 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
1691 local_bh_enable();
1692
1693 return;
1694
1695err:
1696 local_bh_enable();
1697
1698 kfree_skb(skb);
1699
1700 if (net_ratelimit())
1701 netdev_err(dev: ppp->dev, format: "recursion detected\n");
1702}
1703
1704static inline struct sk_buff *
1705pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1706{
1707 struct sk_buff *new_skb;
1708 int len;
1709 int new_skb_size = ppp->dev->mtu +
1710 ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1711 int compressor_skb_size = ppp->dev->mtu +
1712 ppp->xcomp->comp_extra + PPP_HDRLEN;
1713 new_skb = alloc_skb(size: new_skb_size, GFP_ATOMIC);
1714 if (!new_skb) {
1715 if (net_ratelimit())
1716 netdev_err(dev: ppp->dev, format: "PPP: no memory (comp pkt)\n");
1717 return NULL;
1718 }
1719 if (ppp->dev->hard_header_len > PPP_HDRLEN)
1720 skb_reserve(skb: new_skb,
1721 len: ppp->dev->hard_header_len - PPP_HDRLEN);
1722
1723 /* compressor still expects A/C bytes in hdr */
1724 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1725 new_skb->data, skb->len + 2,
1726 compressor_skb_size);
1727 if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1728 consume_skb(skb);
1729 skb = new_skb;
1730 skb_put(skb, len);
1731 skb_pull(skb, len: 2); /* pull off A/C bytes */
1732 } else if (len == 0) {
1733 /* didn't compress, or CCP not up yet */
1734 consume_skb(skb: new_skb);
1735 new_skb = skb;
1736 } else {
1737 /*
1738 * (len < 0)
1739 * MPPE requires that we do not send unencrypted
1740 * frames. The compressor will return -1 if we
1741 * should drop the frame. We cannot simply test
1742 * the compress_proto because MPPE and MPPC share
1743 * the same number.
1744 */
1745 if (net_ratelimit())
1746 netdev_err(dev: ppp->dev, format: "ppp: compressor dropped pkt\n");
1747 consume_skb(skb: new_skb);
1748 new_skb = NULL;
1749 }
1750 return new_skb;
1751}
1752
1753/*
1754 * Compress and send a frame.
1755 * The caller should have locked the xmit path,
1756 * and xmit_pending should be 0.
1757 */
1758static void
1759ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1760{
1761 int proto = PPP_PROTO(skb);
1762 struct sk_buff *new_skb;
1763 int len;
1764 unsigned char *cp;
1765
1766 skb->dev = ppp->dev;
1767
1768 if (proto < 0x8000) {
1769#ifdef CONFIG_PPP_FILTER
1770 /* check if the packet passes the pass and active filters.
1771 * See comment for PPP_FILTER_OUTBOUND_TAG above.
1772 */
1773 *(__be16 *)skb_push(skb, len: 2) = htons(PPP_FILTER_OUTBOUND_TAG);
1774 if (ppp->pass_filter &&
1775 bpf_prog_run(prog: ppp->pass_filter, ctx: skb) == 0) {
1776 if (ppp->debug & 1)
1777 netdev_printk(KERN_DEBUG, dev: ppp->dev,
1778 format: "PPP: outbound frame "
1779 "not passed\n");
1780 kfree_skb(skb);
1781 return;
1782 }
1783 /* if this packet passes the active filter, record the time */
1784 if (!(ppp->active_filter &&
1785 bpf_prog_run(prog: ppp->active_filter, ctx: skb) == 0))
1786 ppp->last_xmit = jiffies;
1787 skb_pull(skb, len: 2);
1788#else
1789 /* for data packets, record the time */
1790 ppp->last_xmit = jiffies;
1791#endif /* CONFIG_PPP_FILTER */
1792 }
1793
1794 dev_sw_netstats_tx_add(dev: ppp->dev, packets: 1, len: skb->len - PPP_PROTO_LEN);
1795
1796 switch (proto) {
1797 case PPP_IP:
1798 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1799 break;
1800 /* try to do VJ TCP header compression */
1801 new_skb = alloc_skb(size: skb->len + ppp->dev->hard_header_len - 2,
1802 GFP_ATOMIC);
1803 if (!new_skb) {
1804 netdev_err(dev: ppp->dev, format: "PPP: no memory (VJ comp pkt)\n");
1805 goto drop;
1806 }
1807 skb_reserve(skb: new_skb, len: ppp->dev->hard_header_len - 2);
1808 cp = skb->data + 2;
1809 len = slhc_compress(comp: ppp->vj, icp: cp, isize: skb->len - 2,
1810 ocp: new_skb->data + 2, cpp: &cp,
1811 compress_cid: !(ppp->flags & SC_NO_TCP_CCID));
1812 if (cp == skb->data + 2) {
1813 /* didn't compress */
1814 consume_skb(skb: new_skb);
1815 } else {
1816 if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1817 proto = PPP_VJC_COMP;
1818 cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1819 } else {
1820 proto = PPP_VJC_UNCOMP;
1821 cp[0] = skb->data[2];
1822 }
1823 consume_skb(skb);
1824 skb = new_skb;
1825 cp = skb_put(skb, len: len + 2);
1826 cp[0] = 0;
1827 cp[1] = proto;
1828 }
1829 break;
1830
1831 case PPP_CCP:
1832 /* peek at outbound CCP frames */
1833 ppp_ccp_peek(ppp, skb, inbound: 0);
1834 break;
1835 }
1836
1837 /* try to do packet compression */
1838 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state &&
1839 proto != PPP_LCP && proto != PPP_CCP) {
1840 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1841 if (net_ratelimit())
1842 netdev_err(dev: ppp->dev,
1843 format: "ppp: compression required but "
1844 "down - pkt dropped.\n");
1845 goto drop;
1846 }
1847 new_skb = pad_compress_skb(ppp, skb);
1848 if (!new_skb)
1849 goto drop;
1850 skb = new_skb;
1851 }
1852
1853 /*
1854 * If we are waiting for traffic (demand dialling),
1855 * queue it up for pppd to receive.
1856 */
1857 if (ppp->flags & SC_LOOP_TRAFFIC) {
1858 if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1859 goto drop;
1860 skb_queue_tail(list: &ppp->file.rq, newsk: skb);
1861 wake_up_interruptible(&ppp->file.rwait);
1862 return;
1863 }
1864
1865 ppp->xmit_pending = skb;
1866 ppp_push(ppp);
1867 return;
1868
1869 drop:
1870 kfree_skb(skb);
1871 ++ppp->dev->stats.tx_errors;
1872}
1873
1874/*
1875 * Try to send the frame in xmit_pending.
1876 * The caller should have the xmit path locked.
1877 */
1878static void
1879ppp_push(struct ppp *ppp)
1880{
1881 struct list_head *list;
1882 struct channel *pch;
1883 struct sk_buff *skb = ppp->xmit_pending;
1884
1885 if (!skb)
1886 return;
1887
1888 list = &ppp->channels;
1889 if (list_empty(head: list)) {
1890 /* nowhere to send the packet, just drop it */
1891 ppp->xmit_pending = NULL;
1892 kfree_skb(skb);
1893 return;
1894 }
1895
1896 if ((ppp->flags & SC_MULTILINK) == 0) {
1897 /* not doing multilink: send it down the first channel */
1898 list = list->next;
1899 pch = list_entry(list, struct channel, clist);
1900
1901 spin_lock(lock: &pch->downl);
1902 if (pch->chan) {
1903 if (pch->chan->ops->start_xmit(pch->chan, skb))
1904 ppp->xmit_pending = NULL;
1905 } else {
1906 /* channel got unregistered */
1907 kfree_skb(skb);
1908 ppp->xmit_pending = NULL;
1909 }
1910 spin_unlock(lock: &pch->downl);
1911 return;
1912 }
1913
1914#ifdef CONFIG_PPP_MULTILINK
1915 /* Multilink: fragment the packet over as many links
1916 as can take the packet at the moment. */
1917 if (!ppp_mp_explode(ppp, skb))
1918 return;
1919#endif /* CONFIG_PPP_MULTILINK */
1920
1921 ppp->xmit_pending = NULL;
1922 kfree_skb(skb);
1923}
1924
1925#ifdef CONFIG_PPP_MULTILINK
1926static bool mp_protocol_compress __read_mostly = true;
1927module_param(mp_protocol_compress, bool, 0644);
1928MODULE_PARM_DESC(mp_protocol_compress,
1929 "compress protocol id in multilink fragments");
1930
1931/*
1932 * Divide a packet to be transmitted into fragments and
1933 * send them out the individual links.
1934 */
1935static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1936{
1937 int len, totlen;
1938 int i, bits, hdrlen, mtu;
1939 int flen;
1940 int navail, nfree, nzero;
1941 int nbigger;
1942 int totspeed;
1943 int totfree;
1944 unsigned char *p, *q;
1945 struct list_head *list;
1946 struct channel *pch;
1947 struct sk_buff *frag;
1948 struct ppp_channel *chan;
1949
1950 totspeed = 0; /*total bitrate of the bundle*/
1951 nfree = 0; /* # channels which have no packet already queued */
1952 navail = 0; /* total # of usable channels (not deregistered) */
1953 nzero = 0; /* number of channels with zero speed associated*/
1954 totfree = 0; /*total # of channels available and
1955 *having no queued packets before
1956 *starting the fragmentation*/
1957
1958 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1959 i = 0;
1960 list_for_each_entry(pch, &ppp->channels, clist) {
1961 if (pch->chan) {
1962 pch->avail = 1;
1963 navail++;
1964 pch->speed = pch->chan->speed;
1965 } else {
1966 pch->avail = 0;
1967 }
1968 if (pch->avail) {
1969 if (skb_queue_empty(list: &pch->file.xq) ||
1970 !pch->had_frag) {
1971 if (pch->speed == 0)
1972 nzero++;
1973 else
1974 totspeed += pch->speed;
1975
1976 pch->avail = 2;
1977 ++nfree;
1978 ++totfree;
1979 }
1980 if (!pch->had_frag && i < ppp->nxchan)
1981 ppp->nxchan = i;
1982 }
1983 ++i;
1984 }
1985 /*
1986 * Don't start sending this packet unless at least half of
1987 * the channels are free. This gives much better TCP
1988 * performance if we have a lot of channels.
1989 */
1990 if (nfree == 0 || nfree < navail / 2)
1991 return 0; /* can't take now, leave it in xmit_pending */
1992
1993 /* Do protocol field compression */
1994 p = skb->data;
1995 len = skb->len;
1996 if (*p == 0 && mp_protocol_compress) {
1997 ++p;
1998 --len;
1999 }
2000
2001 totlen = len;
2002 nbigger = len % nfree;
2003
2004 /* skip to the channel after the one we last used
2005 and start at that one */
2006 list = &ppp->channels;
2007 for (i = 0; i < ppp->nxchan; ++i) {
2008 list = list->next;
2009 if (list == &ppp->channels) {
2010 i = 0;
2011 break;
2012 }
2013 }
2014
2015 /* create a fragment for each channel */
2016 bits = B;
2017 while (len > 0) {
2018 list = list->next;
2019 if (list == &ppp->channels) {
2020 i = 0;
2021 continue;
2022 }
2023 pch = list_entry(list, struct channel, clist);
2024 ++i;
2025 if (!pch->avail)
2026 continue;
2027
2028 /*
2029 * Skip this channel if it has a fragment pending already and
2030 * we haven't given a fragment to all of the free channels.
2031 */
2032 if (pch->avail == 1) {
2033 if (nfree > 0)
2034 continue;
2035 } else {
2036 pch->avail = 1;
2037 }
2038
2039 /* check the channel's mtu and whether it is still attached. */
2040 spin_lock(lock: &pch->downl);
2041 if (pch->chan == NULL) {
2042 /* can't use this channel, it's being deregistered */
2043 if (pch->speed == 0)
2044 nzero--;
2045 else
2046 totspeed -= pch->speed;
2047
2048 spin_unlock(lock: &pch->downl);
2049 pch->avail = 0;
2050 totlen = len;
2051 totfree--;
2052 nfree--;
2053 if (--navail == 0)
2054 break;
2055 continue;
2056 }
2057
2058 /*
2059 *if the channel speed is not set divide
2060 *the packet evenly among the free channels;
2061 *otherwise divide it according to the speed
2062 *of the channel we are going to transmit on
2063 */
2064 flen = len;
2065 if (nfree > 0) {
2066 if (pch->speed == 0) {
2067 flen = len/nfree;
2068 if (nbigger > 0) {
2069 flen++;
2070 nbigger--;
2071 }
2072 } else {
2073 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
2074 ((totspeed*totfree)/pch->speed)) - hdrlen;
2075 if (nbigger > 0) {
2076 flen += ((totfree - nzero)*pch->speed)/totspeed;
2077 nbigger -= ((totfree - nzero)*pch->speed)/
2078 totspeed;
2079 }
2080 }
2081 nfree--;
2082 }
2083
2084 /*
2085 *check if we are on the last channel or
2086 *we exceded the length of the data to
2087 *fragment
2088 */
2089 if ((nfree <= 0) || (flen > len))
2090 flen = len;
2091 /*
2092 *it is not worth to tx on slow channels:
2093 *in that case from the resulting flen according to the
2094 *above formula will be equal or less than zero.
2095 *Skip the channel in this case
2096 */
2097 if (flen <= 0) {
2098 pch->avail = 2;
2099 spin_unlock(lock: &pch->downl);
2100 continue;
2101 }
2102
2103 /*
2104 * hdrlen includes the 2-byte PPP protocol field, but the
2105 * MTU counts only the payload excluding the protocol field.
2106 * (RFC1661 Section 2)
2107 */
2108 mtu = pch->chan->mtu - (hdrlen - 2);
2109 if (mtu < 4)
2110 mtu = 4;
2111 if (flen > mtu)
2112 flen = mtu;
2113 if (flen == len)
2114 bits |= E;
2115 frag = alloc_skb(size: flen + hdrlen + (flen == 0), GFP_ATOMIC);
2116 if (!frag)
2117 goto noskb;
2118 q = skb_put(skb: frag, len: flen + hdrlen);
2119
2120 /* make the MP header */
2121 put_unaligned_be16(PPP_MP, p: q);
2122 if (ppp->flags & SC_MP_XSHORTSEQ) {
2123 q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
2124 q[3] = ppp->nxseq;
2125 } else {
2126 q[2] = bits;
2127 q[3] = ppp->nxseq >> 16;
2128 q[4] = ppp->nxseq >> 8;
2129 q[5] = ppp->nxseq;
2130 }
2131
2132 memcpy(q + hdrlen, p, flen);
2133
2134 /* try to send it down the channel */
2135 chan = pch->chan;
2136 if (!skb_queue_empty(list: &pch->file.xq) ||
2137 !chan->ops->start_xmit(chan, frag))
2138 skb_queue_tail(list: &pch->file.xq, newsk: frag);
2139 pch->had_frag = 1;
2140 p += flen;
2141 len -= flen;
2142 ++ppp->nxseq;
2143 bits = 0;
2144 spin_unlock(lock: &pch->downl);
2145 }
2146 ppp->nxchan = i;
2147
2148 return 1;
2149
2150 noskb:
2151 spin_unlock(lock: &pch->downl);
2152 if (ppp->debug & 1)
2153 netdev_err(dev: ppp->dev, format: "PPP: no memory (fragment)\n");
2154 ++ppp->dev->stats.tx_errors;
2155 ++ppp->nxseq;
2156 return 1; /* abandon the frame */
2157}
2158#endif /* CONFIG_PPP_MULTILINK */
2159
2160/* Try to send data out on a channel */
2161static void __ppp_channel_push(struct channel *pch, struct ppp *ppp)
2162{
2163 struct sk_buff *skb;
2164
2165 spin_lock(lock: &pch->downl);
2166 if (pch->chan) {
2167 while (!skb_queue_empty(list: &pch->file.xq)) {
2168 skb = skb_dequeue(list: &pch->file.xq);
2169 if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
2170 /* put the packet back and try again later */
2171 skb_queue_head(list: &pch->file.xq, newsk: skb);
2172 break;
2173 }
2174 }
2175 } else {
2176 /* channel got deregistered */
2177 skb_queue_purge(list: &pch->file.xq);
2178 }
2179 spin_unlock(lock: &pch->downl);
2180 /* see if there is anything from the attached unit to be sent */
2181 if (skb_queue_empty(list: &pch->file.xq)) {
2182 if (ppp)
2183 __ppp_xmit_process(ppp, NULL);
2184 }
2185}
2186
2187static void ppp_channel_push(struct channel *pch)
2188{
2189 struct ppp_xmit_recursion *xmit_recursion;
2190 struct ppp *ppp;
2191
2192 rcu_read_lock_bh();
2193 ppp = rcu_dereference_bh(pch->ppp);
2194 if (ppp) {
2195 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
2196 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
2197 xmit_recursion->owner = current;
2198 __ppp_channel_push(pch, ppp);
2199 xmit_recursion->owner = NULL;
2200 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
2201 } else {
2202 __ppp_channel_push(pch, NULL);
2203 }
2204 rcu_read_unlock_bh();
2205}
2206
2207/*
2208 * Receive-side routines.
2209 */
2210
2211struct ppp_mp_skb_parm {
2212 u32 sequence;
2213 u8 BEbits;
2214};
2215#define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb))
2216
2217static inline void
2218ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2219{
2220 ppp_recv_lock(ppp);
2221 if (!ppp->closing)
2222 ppp_receive_frame(ppp, skb, pch);
2223 else
2224 kfree_skb(skb);
2225 ppp_recv_unlock(ppp);
2226}
2227
2228/**
2229 * __ppp_decompress_proto - Decompress protocol field, slim version.
2230 * @skb: Socket buffer where protocol field should be decompressed. It must have
2231 * at least 1 byte of head room and 1 byte of linear data. First byte of
2232 * data must be a protocol field byte.
2233 *
2234 * Decompress protocol field in PPP header if it's compressed, e.g. when
2235 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data
2236 * length are done in this function.
2237 */
2238static void __ppp_decompress_proto(struct sk_buff *skb)
2239{
2240 if (skb->data[0] & 0x01)
2241 *(u8 *)skb_push(skb, len: 1) = 0x00;
2242}
2243
2244/**
2245 * ppp_decompress_proto - Check skb data room and decompress protocol field.
2246 * @skb: Socket buffer where protocol field should be decompressed. First byte
2247 * of data must be a protocol field byte.
2248 *
2249 * Decompress protocol field in PPP header if it's compressed, e.g. when
2250 * Protocol-Field-Compression (PFC) was negotiated. This function also makes
2251 * sure that skb data room is sufficient for Protocol field, before and after
2252 * decompression.
2253 *
2254 * Return: true - decompressed successfully, false - not enough room in skb.
2255 */
2256static bool ppp_decompress_proto(struct sk_buff *skb)
2257{
2258 /* At least one byte should be present (if protocol is compressed) */
2259 if (!pskb_may_pull(skb, len: 1))
2260 return false;
2261
2262 __ppp_decompress_proto(skb);
2263
2264 /* Protocol field should occupy 2 bytes when not compressed */
2265 return pskb_may_pull(skb, len: 2);
2266}
2267
2268/* Attempt to handle a frame via. a bridged channel, if one exists.
2269 * If the channel is bridged, the frame is consumed by the bridge.
2270 * If not, the caller must handle the frame by normal recv mechanisms.
2271 * Returns true if the frame is consumed, false otherwise.
2272 */
2273static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
2274{
2275 struct channel *pchb;
2276
2277 rcu_read_lock();
2278 pchb = rcu_dereference(pch->bridge);
2279 if (!pchb)
2280 goto out_rcu;
2281
2282 spin_lock_bh(lock: &pchb->downl);
2283 if (!pchb->chan) {
2284 /* channel got unregistered */
2285 kfree_skb(skb);
2286 goto outl;
2287 }
2288
2289 skb_scrub_packet(skb, xnet: !net_eq(net1: pch->chan_net, net2: pchb->chan_net));
2290 if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
2291 kfree_skb(skb);
2292
2293outl:
2294 spin_unlock_bh(lock: &pchb->downl);
2295out_rcu:
2296 rcu_read_unlock();
2297
2298 /* If pchb is set then we've consumed the packet */
2299 return !!pchb;
2300}
2301
2302void
2303ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
2304{
2305 struct channel *pch = chan->ppp;
2306 struct ppp *ppp;
2307 int proto;
2308
2309 if (!pch) {
2310 kfree_skb(skb);
2311 return;
2312 }
2313
2314 /* If the channel is bridged, transmit via. bridge */
2315 if (ppp_channel_bridge_input(pch, skb))
2316 return;
2317
2318 rcu_read_lock_bh();
2319 ppp = rcu_dereference_bh(pch->ppp);
2320 if (!ppp_decompress_proto(skb)) {
2321 kfree_skb(skb);
2322 if (ppp) {
2323 ++ppp->dev->stats.rx_length_errors;
2324 ppp_receive_error(ppp);
2325 }
2326 goto done;
2327 }
2328
2329 proto = PPP_PROTO(skb);
2330 if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
2331 /* put it on the channel queue */
2332 skb_queue_tail(list: &pch->file.rq, newsk: skb);
2333 /* drop old frames if queue too long */
2334 while (pch->file.rq.qlen > PPP_MAX_RQLEN &&
2335 (skb = skb_dequeue(list: &pch->file.rq)))
2336 kfree_skb(skb);
2337 wake_up_interruptible(&pch->file.rwait);
2338 } else {
2339 ppp_do_recv(ppp, skb, pch);
2340 }
2341
2342done:
2343 rcu_read_unlock_bh();
2344}
2345
2346/* Put a 0-length skb in the receive queue as an error indication */
2347void
2348ppp_input_error(struct ppp_channel *chan, int code)
2349{
2350 struct channel *pch = chan->ppp;
2351 struct sk_buff *skb;
2352 struct ppp *ppp;
2353
2354 if (!pch)
2355 return;
2356
2357 rcu_read_lock_bh();
2358 ppp = rcu_dereference_bh(pch->ppp);
2359 if (ppp) {
2360 skb = alloc_skb(size: 0, GFP_ATOMIC);
2361 if (skb) {
2362 skb->len = 0; /* probably unnecessary */
2363 skb->cb[0] = code;
2364 ppp_do_recv(ppp, skb, pch);
2365 }
2366 }
2367 rcu_read_unlock_bh();
2368}
2369
2370/*
2371 * We come in here to process a received frame.
2372 * The receive side of the ppp unit is locked.
2373 */
2374static void
2375ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2376{
2377 /* note: a 0-length skb is used as an error indication */
2378 if (skb->len > 0) {
2379 skb_checksum_complete_unset(skb);
2380#ifdef CONFIG_PPP_MULTILINK
2381 /* XXX do channel-level decompression here */
2382 if (PPP_PROTO(skb) == PPP_MP)
2383 ppp_receive_mp_frame(ppp, skb, pch);
2384 else
2385#endif /* CONFIG_PPP_MULTILINK */
2386 ppp_receive_nonmp_frame(ppp, skb);
2387 } else {
2388 kfree_skb(skb);
2389 ppp_receive_error(ppp);
2390 }
2391}
2392
2393static void
2394ppp_receive_error(struct ppp *ppp)
2395{
2396 ++ppp->dev->stats.rx_errors;
2397 if (ppp->vj)
2398 slhc_toss(comp: ppp->vj);
2399}
2400
2401static void
2402ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
2403{
2404 struct sk_buff *ns;
2405 int proto, len, npi;
2406
2407 /*
2408 * Decompress the frame, if compressed.
2409 * Note that some decompressors need to see uncompressed frames
2410 * that come in as well as compressed frames.
2411 */
2412 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) &&
2413 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
2414 skb = ppp_decompress_frame(ppp, skb);
2415
2416 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
2417 goto err;
2418
2419 /* At this point the "Protocol" field MUST be decompressed, either in
2420 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame().
2421 */
2422 proto = PPP_PROTO(skb);
2423 switch (proto) {
2424 case PPP_VJC_COMP:
2425 /* decompress VJ compressed packets */
2426 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2427 goto err;
2428
2429 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
2430 /* copy to a new sk_buff with more tailroom */
2431 ns = dev_alloc_skb(length: skb->len + 128);
2432 if (!ns) {
2433 netdev_err(dev: ppp->dev, format: "PPP: no memory "
2434 "(VJ decomp)\n");
2435 goto err;
2436 }
2437 skb_reserve(skb: ns, len: 2);
2438 skb_copy_bits(skb, offset: 0, to: skb_put(skb: ns, len: skb->len), len: skb->len);
2439 consume_skb(skb);
2440 skb = ns;
2441 }
2442 else
2443 skb->ip_summed = CHECKSUM_NONE;
2444
2445 len = slhc_uncompress(comp: ppp->vj, icp: skb->data + 2, isize: skb->len - 2);
2446 if (len <= 0) {
2447 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2448 format: "PPP: VJ decompression error\n");
2449 goto err;
2450 }
2451 len += 2;
2452 if (len > skb->len)
2453 skb_put(skb, len: len - skb->len);
2454 else if (len < skb->len)
2455 skb_trim(skb, len);
2456 proto = PPP_IP;
2457 break;
2458
2459 case PPP_VJC_UNCOMP:
2460 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
2461 goto err;
2462
2463 /* Until we fix the decompressor need to make sure
2464 * data portion is linear.
2465 */
2466 if (!pskb_may_pull(skb, len: skb->len))
2467 goto err;
2468
2469 if (slhc_remember(comp: ppp->vj, icp: skb->data + 2, isize: skb->len - 2) <= 0) {
2470 netdev_err(dev: ppp->dev, format: "PPP: VJ uncompressed error\n");
2471 goto err;
2472 }
2473 proto = PPP_IP;
2474 break;
2475
2476 case PPP_CCP:
2477 ppp_ccp_peek(ppp, skb, inbound: 1);
2478 break;
2479 }
2480
2481 dev_sw_netstats_rx_add(dev: ppp->dev, len: skb->len - PPP_PROTO_LEN);
2482
2483 npi = proto_to_npindex(proto);
2484 if (npi < 0) {
2485 /* control or unknown frame - pass it to pppd */
2486 skb_queue_tail(list: &ppp->file.rq, newsk: skb);
2487 /* limit queue length by dropping old frames */
2488 while (ppp->file.rq.qlen > PPP_MAX_RQLEN &&
2489 (skb = skb_dequeue(list: &ppp->file.rq)))
2490 kfree_skb(skb);
2491 /* wake up any process polling or blocking on read */
2492 wake_up_interruptible(&ppp->file.rwait);
2493
2494 } else {
2495 /* network protocol frame - give it to the kernel */
2496
2497#ifdef CONFIG_PPP_FILTER
2498 if (ppp->pass_filter || ppp->active_filter) {
2499 if (skb_unclone(skb, GFP_ATOMIC))
2500 goto err;
2501 /* Check if the packet passes the pass and active filters.
2502 * See comment for PPP_FILTER_INBOUND_TAG above.
2503 */
2504 *(__be16 *)skb_push(skb, len: 2) = htons(PPP_FILTER_INBOUND_TAG);
2505 if (ppp->pass_filter &&
2506 bpf_prog_run(prog: ppp->pass_filter, ctx: skb) == 0) {
2507 if (ppp->debug & 1)
2508 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2509 format: "PPP: inbound frame "
2510 "not passed\n");
2511 kfree_skb(skb);
2512 return;
2513 }
2514 if (!(ppp->active_filter &&
2515 bpf_prog_run(prog: ppp->active_filter, ctx: skb) == 0))
2516 ppp->last_recv = jiffies;
2517 __skb_pull(skb, len: 2);
2518 } else
2519#endif /* CONFIG_PPP_FILTER */
2520 ppp->last_recv = jiffies;
2521
2522 if ((ppp->dev->flags & IFF_UP) == 0 ||
2523 ppp->npmode[npi] != NPMODE_PASS) {
2524 kfree_skb(skb);
2525 } else {
2526 /* chop off protocol */
2527 skb_pull_rcsum(skb, len: 2);
2528 skb->dev = ppp->dev;
2529 skb->protocol = htons(npindex_to_ethertype[npi]);
2530 skb_reset_mac_header(skb);
2531 skb_scrub_packet(skb, xnet: !net_eq(net1: ppp->ppp_net,
2532 net2: dev_net(dev: ppp->dev)));
2533 netif_rx(skb);
2534 }
2535 }
2536 return;
2537
2538 err:
2539 kfree_skb(skb);
2540 ppp_receive_error(ppp);
2541}
2542
2543static struct sk_buff *
2544ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
2545{
2546 int proto = PPP_PROTO(skb);
2547 struct sk_buff *ns;
2548 int len;
2549
2550 /* Until we fix all the decompressor's need to make sure
2551 * data portion is linear.
2552 */
2553 if (!pskb_may_pull(skb, len: skb->len))
2554 goto err;
2555
2556 if (proto == PPP_COMP) {
2557 int obuff_size;
2558
2559 switch(ppp->rcomp->compress_proto) {
2560 case CI_MPPE:
2561 obuff_size = ppp->mru + PPP_HDRLEN + 1;
2562 break;
2563 default:
2564 obuff_size = ppp->mru + PPP_HDRLEN;
2565 break;
2566 }
2567
2568 ns = dev_alloc_skb(length: obuff_size);
2569 if (!ns) {
2570 netdev_err(dev: ppp->dev, format: "ppp_decompress_frame: "
2571 "no memory\n");
2572 goto err;
2573 }
2574 /* the decompressor still expects the A/C bytes in the hdr */
2575 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
2576 skb->len + 2, ns->data, obuff_size);
2577 if (len < 0) {
2578 /* Pass the compressed frame to pppd as an
2579 error indication. */
2580 if (len == DECOMP_FATALERROR)
2581 ppp->rstate |= SC_DC_FERROR;
2582 kfree_skb(skb: ns);
2583 goto err;
2584 }
2585
2586 consume_skb(skb);
2587 skb = ns;
2588 skb_put(skb, len);
2589 skb_pull(skb, len: 2); /* pull off the A/C bytes */
2590
2591 /* Don't call __ppp_decompress_proto() here, but instead rely on
2592 * corresponding algo (mppe/bsd/deflate) to decompress it.
2593 */
2594 } else {
2595 /* Uncompressed frame - pass to decompressor so it
2596 can update its dictionary if necessary. */
2597 if (ppp->rcomp->incomp)
2598 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
2599 skb->len + 2);
2600 }
2601
2602 return skb;
2603
2604 err:
2605 ppp->rstate |= SC_DC_ERROR;
2606 ppp_receive_error(ppp);
2607 return skb;
2608}
2609
2610#ifdef CONFIG_PPP_MULTILINK
2611/*
2612 * Receive a multilink frame.
2613 * We put it on the reconstruction queue and then pull off
2614 * as many completed frames as we can.
2615 */
2616static void
2617ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
2618{
2619 u32 mask, seq;
2620 struct channel *ch;
2621 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
2622
2623 if (!pskb_may_pull(skb, len: mphdrlen + 1) || ppp->mrru == 0)
2624 goto err; /* no good, throw it away */
2625
2626 /* Decode sequence number and begin/end bits */
2627 if (ppp->flags & SC_MP_SHORTSEQ) {
2628 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
2629 mask = 0xfff;
2630 } else {
2631 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
2632 mask = 0xffffff;
2633 }
2634 PPP_MP_CB(skb)->BEbits = skb->data[2];
2635 skb_pull(skb, len: mphdrlen); /* pull off PPP and MP headers */
2636
2637 /*
2638 * Do protocol ID decompression on the first fragment of each packet.
2639 * We have to do that here, because ppp_receive_nonmp_frame() expects
2640 * decompressed protocol field.
2641 */
2642 if (PPP_MP_CB(skb)->BEbits & B)
2643 __ppp_decompress_proto(skb);
2644
2645 /*
2646 * Expand sequence number to 32 bits, making it as close
2647 * as possible to ppp->minseq.
2648 */
2649 seq |= ppp->minseq & ~mask;
2650 if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
2651 seq += mask + 1;
2652 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
2653 seq -= mask + 1; /* should never happen */
2654 PPP_MP_CB(skb)->sequence = seq;
2655 pch->lastseq = seq;
2656
2657 /*
2658 * If this packet comes before the next one we were expecting,
2659 * drop it.
2660 */
2661 if (seq_before(seq, ppp->nextseq)) {
2662 kfree_skb(skb);
2663 ++ppp->dev->stats.rx_dropped;
2664 ppp_receive_error(ppp);
2665 return;
2666 }
2667
2668 /*
2669 * Reevaluate minseq, the minimum over all channels of the
2670 * last sequence number received on each channel. Because of
2671 * the increasing sequence number rule, we know that any fragment
2672 * before `minseq' which hasn't arrived is never going to arrive.
2673 * The list of channels can't change because we have the receive
2674 * side of the ppp unit locked.
2675 */
2676 list_for_each_entry(ch, &ppp->channels, clist) {
2677 if (seq_before(ch->lastseq, seq))
2678 seq = ch->lastseq;
2679 }
2680 if (seq_before(ppp->minseq, seq))
2681 ppp->minseq = seq;
2682
2683 /* Put the fragment on the reconstruction queue */
2684 ppp_mp_insert(ppp, skb);
2685
2686 /* If the queue is getting long, don't wait any longer for packets
2687 before the start of the queue. */
2688 if (skb_queue_len(list_: &ppp->mrq) >= PPP_MP_MAX_QLEN) {
2689 struct sk_buff *mskb = skb_peek(list_: &ppp->mrq);
2690 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence))
2691 ppp->minseq = PPP_MP_CB(mskb)->sequence;
2692 }
2693
2694 /* Pull completed packets off the queue and receive them. */
2695 while ((skb = ppp_mp_reconstruct(ppp))) {
2696 if (pskb_may_pull(skb, len: 2))
2697 ppp_receive_nonmp_frame(ppp, skb);
2698 else {
2699 ++ppp->dev->stats.rx_length_errors;
2700 kfree_skb(skb);
2701 ppp_receive_error(ppp);
2702 }
2703 }
2704
2705 return;
2706
2707 err:
2708 kfree_skb(skb);
2709 ppp_receive_error(ppp);
2710}
2711
2712/*
2713 * Insert a fragment on the MP reconstruction queue.
2714 * The queue is ordered by increasing sequence number.
2715 */
2716static void
2717ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
2718{
2719 struct sk_buff *p;
2720 struct sk_buff_head *list = &ppp->mrq;
2721 u32 seq = PPP_MP_CB(skb)->sequence;
2722
2723 /* N.B. we don't need to lock the list lock because we have the
2724 ppp unit receive-side lock. */
2725 skb_queue_walk(list, p) {
2726 if (seq_before(seq, PPP_MP_CB(p)->sequence))
2727 break;
2728 }
2729 __skb_queue_before(list, next: p, newsk: skb);
2730}
2731
2732/*
2733 * Reconstruct a packet from the MP fragment queue.
2734 * We go through increasing sequence numbers until we find a
2735 * complete packet, or we get to the sequence number for a fragment
2736 * which hasn't arrived but might still do so.
2737 */
2738static struct sk_buff *
2739ppp_mp_reconstruct(struct ppp *ppp)
2740{
2741 u32 seq = ppp->nextseq;
2742 u32 minseq = ppp->minseq;
2743 struct sk_buff_head *list = &ppp->mrq;
2744 struct sk_buff *p, *tmp;
2745 struct sk_buff *head, *tail;
2746 struct sk_buff *skb = NULL;
2747 int lost = 0, len = 0;
2748
2749 if (ppp->mrru == 0) /* do nothing until mrru is set */
2750 return NULL;
2751 head = __skb_peek(list_: list);
2752 tail = NULL;
2753 skb_queue_walk_safe(list, p, tmp) {
2754 again:
2755 if (seq_before(PPP_MP_CB(p)->sequence, seq)) {
2756 /* this can't happen, anyway ignore the skb */
2757 netdev_err(dev: ppp->dev, format: "ppp_mp_reconstruct bad "
2758 "seq %u < %u\n",
2759 PPP_MP_CB(p)->sequence, seq);
2760 __skb_unlink(skb: p, list);
2761 kfree_skb(skb: p);
2762 continue;
2763 }
2764 if (PPP_MP_CB(p)->sequence != seq) {
2765 u32 oldseq;
2766 /* Fragment `seq' is missing. If it is after
2767 minseq, it might arrive later, so stop here. */
2768 if (seq_after(seq, minseq))
2769 break;
2770 /* Fragment `seq' is lost, keep going. */
2771 lost = 1;
2772 oldseq = seq;
2773 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)?
2774 minseq + 1: PPP_MP_CB(p)->sequence;
2775
2776 if (ppp->debug & 1)
2777 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2778 format: "lost frag %u..%u\n",
2779 oldseq, seq-1);
2780
2781 goto again;
2782 }
2783
2784 /*
2785 * At this point we know that all the fragments from
2786 * ppp->nextseq to seq are either present or lost.
2787 * Also, there are no complete packets in the queue
2788 * that have no missing fragments and end before this
2789 * fragment.
2790 */
2791
2792 /* B bit set indicates this fragment starts a packet */
2793 if (PPP_MP_CB(p)->BEbits & B) {
2794 head = p;
2795 lost = 0;
2796 len = 0;
2797 }
2798
2799 len += p->len;
2800
2801 /* Got a complete packet yet? */
2802 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) &&
2803 (PPP_MP_CB(head)->BEbits & B)) {
2804 if (len > ppp->mrru + 2) {
2805 ++ppp->dev->stats.rx_length_errors;
2806 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2807 format: "PPP: reconstructed packet"
2808 " is too long (%d)\n", len);
2809 } else {
2810 tail = p;
2811 break;
2812 }
2813 ppp->nextseq = seq + 1;
2814 }
2815
2816 /*
2817 * If this is the ending fragment of a packet,
2818 * and we haven't found a complete valid packet yet,
2819 * we can discard up to and including this fragment.
2820 */
2821 if (PPP_MP_CB(p)->BEbits & E) {
2822 struct sk_buff *tmp2;
2823
2824 skb_queue_reverse_walk_from_safe(list, p, tmp2) {
2825 if (ppp->debug & 1)
2826 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2827 format: "discarding frag %u\n",
2828 PPP_MP_CB(p)->sequence);
2829 __skb_unlink(skb: p, list);
2830 kfree_skb(skb: p);
2831 }
2832 head = skb_peek(list_: list);
2833 if (!head)
2834 break;
2835 }
2836 ++seq;
2837 }
2838
2839 /* If we have a complete packet, copy it all into one skb. */
2840 if (tail != NULL) {
2841 /* If we have discarded any fragments,
2842 signal a receive error. */
2843 if (PPP_MP_CB(head)->sequence != ppp->nextseq) {
2844 skb_queue_walk_safe(list, p, tmp) {
2845 if (p == head)
2846 break;
2847 if (ppp->debug & 1)
2848 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2849 format: "discarding frag %u\n",
2850 PPP_MP_CB(p)->sequence);
2851 __skb_unlink(skb: p, list);
2852 kfree_skb(skb: p);
2853 }
2854
2855 if (ppp->debug & 1)
2856 netdev_printk(KERN_DEBUG, dev: ppp->dev,
2857 format: " missed pkts %u..%u\n",
2858 ppp->nextseq,
2859 PPP_MP_CB(head)->sequence-1);
2860 ++ppp->dev->stats.rx_dropped;
2861 ppp_receive_error(ppp);
2862 }
2863
2864 skb = head;
2865 if (head != tail) {
2866 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list;
2867 p = skb_queue_next(list, skb: head);
2868 __skb_unlink(skb, list);
2869 skb_queue_walk_from_safe(list, p, tmp) {
2870 __skb_unlink(skb: p, list);
2871 *fragpp = p;
2872 p->next = NULL;
2873 fragpp = &p->next;
2874
2875 skb->len += p->len;
2876 skb->data_len += p->len;
2877 skb->truesize += p->truesize;
2878
2879 if (p == tail)
2880 break;
2881 }
2882 } else {
2883 __skb_unlink(skb, list);
2884 }
2885
2886 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1;
2887 }
2888
2889 return skb;
2890}
2891#endif /* CONFIG_PPP_MULTILINK */
2892
2893/*
2894 * Channel interface.
2895 */
2896
2897/* Create a new, unattached ppp channel. */
2898int ppp_register_channel(struct ppp_channel *chan)
2899{
2900 return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2901}
2902
2903/* Create a new, unattached ppp channel for specified net. */
2904int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2905{
2906 struct channel *pch;
2907 struct ppp_net *pn;
2908
2909 pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2910 if (!pch)
2911 return -ENOMEM;
2912
2913 pn = ppp_pernet(net);
2914
2915 pch->chan = chan;
2916 pch->chan_net = get_net_track(net, tracker: &pch->ns_tracker, GFP_KERNEL);
2917 chan->ppp = pch;
2918 init_ppp_file(pf: &pch->file, kind: CHANNEL);
2919 pch->file.hdrlen = chan->hdrlen;
2920#ifdef CONFIG_PPP_MULTILINK
2921 pch->lastseq = -1;
2922#endif /* CONFIG_PPP_MULTILINK */
2923 init_rwsem(&pch->chan_sem);
2924 spin_lock_init(&pch->downl);
2925 spin_lock_init(&pch->upl);
2926
2927 spin_lock_bh(lock: &pn->all_channels_lock);
2928 pch->file.index = ++pn->last_channel_index;
2929 list_add(new: &pch->list, head: &pn->new_channels);
2930 atomic_inc(v: &channel_count);
2931 spin_unlock_bh(lock: &pn->all_channels_lock);
2932
2933 return 0;
2934}
2935
2936/*
2937 * Return the index of a channel.
2938 */
2939int ppp_channel_index(struct ppp_channel *chan)
2940{
2941 struct channel *pch = chan->ppp;
2942
2943 if (pch)
2944 return pch->file.index;
2945 return -1;
2946}
2947
2948/*
2949 * Return the PPP unit number to which a channel is connected.
2950 */
2951int ppp_unit_number(struct ppp_channel *chan)
2952{
2953 struct channel *pch = chan->ppp;
2954 struct ppp *ppp;
2955 int unit = -1;
2956
2957 if (pch) {
2958 rcu_read_lock();
2959 ppp = rcu_dereference(pch->ppp);
2960 if (ppp)
2961 unit = ppp->file.index;
2962 rcu_read_unlock();
2963 }
2964 return unit;
2965}
2966
2967/*
2968 * Return the PPP device interface name of a channel.
2969 */
2970char *ppp_dev_name(struct ppp_channel *chan)
2971{
2972 struct channel *pch = chan->ppp;
2973 char *name = NULL;
2974 struct ppp *ppp;
2975
2976 if (pch) {
2977 rcu_read_lock();
2978 ppp = rcu_dereference(pch->ppp);
2979 if (ppp && ppp->dev)
2980 name = ppp->dev->name;
2981 rcu_read_unlock();
2982 }
2983 return name;
2984}
2985
2986
2987/*
2988 * Disconnect a channel from the generic layer.
2989 * This must be called in process context.
2990 */
2991void
2992ppp_unregister_channel(struct ppp_channel *chan)
2993{
2994 struct channel *pch = chan->ppp;
2995 struct ppp_net *pn;
2996
2997 if (!pch)
2998 return; /* should never happen */
2999
3000 chan->ppp = NULL;
3001
3002 /*
3003 * This ensures that we have returned from any calls into
3004 * the channel's start_xmit or ioctl routine before we proceed.
3005 */
3006 down_write(sem: &pch->chan_sem);
3007 spin_lock_bh(lock: &pch->downl);
3008 WRITE_ONCE(pch->chan, NULL);
3009 spin_unlock_bh(lock: &pch->downl);
3010 up_write(sem: &pch->chan_sem);
3011 ppp_disconnect_channel(pch);
3012
3013 pn = ppp_pernet(net: pch->chan_net);
3014 spin_lock_bh(lock: &pn->all_channels_lock);
3015 list_del(entry: &pch->list);
3016 spin_unlock_bh(lock: &pn->all_channels_lock);
3017
3018 ppp_unbridge_channels(pch);
3019
3020 pch->file.dead = 1;
3021 wake_up_interruptible(&pch->file.rwait);
3022
3023 if (refcount_dec_and_test(r: &pch->file.refcnt))
3024 ppp_destroy_channel(pch);
3025}
3026
3027/*
3028 * Callback from a channel when it can accept more to transmit.
3029 * This should be called at BH/softirq level, not interrupt level.
3030 */
3031void
3032ppp_output_wakeup(struct ppp_channel *chan)
3033{
3034 struct channel *pch = chan->ppp;
3035
3036 if (!pch)
3037 return;
3038 ppp_channel_push(pch);
3039}
3040
3041/*
3042 * Compression control.
3043 */
3044
3045/* Process the PPPIOCSCOMPRESS ioctl. */
3046static int
3047ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
3048{
3049 int err = -EFAULT;
3050 struct compressor *cp, *ocomp;
3051 void *state, *ostate;
3052 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
3053
3054 if (data->length > CCP_MAX_OPTION_LENGTH)
3055 goto out;
3056 if (copy_from_user(to: ccp_option, from: data->ptr, n: data->length))
3057 goto out;
3058
3059 err = -EINVAL;
3060 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
3061 goto out;
3062
3063 cp = try_then_request_module(
3064 find_compressor(ccp_option[0]),
3065 "ppp-compress-%d", ccp_option[0]);
3066 if (!cp)
3067 goto out;
3068
3069 err = -ENOBUFS;
3070 if (data->transmit) {
3071 state = cp->comp_alloc(ccp_option, data->length);
3072 if (state) {
3073 ppp_xmit_lock(ppp);
3074 ppp->xstate &= ~SC_COMP_RUN;
3075 ocomp = ppp->xcomp;
3076 ostate = ppp->xc_state;
3077 ppp->xcomp = cp;
3078 ppp->xc_state = state;
3079 ppp_xmit_unlock(ppp);
3080 if (ostate) {
3081 ocomp->comp_free(ostate);
3082 module_put(module: ocomp->owner);
3083 }
3084 err = 0;
3085 } else
3086 module_put(module: cp->owner);
3087
3088 } else {
3089 state = cp->decomp_alloc(ccp_option, data->length);
3090 if (state) {
3091 ppp_recv_lock(ppp);
3092 ppp->rstate &= ~SC_DECOMP_RUN;
3093 ocomp = ppp->rcomp;
3094 ostate = ppp->rc_state;
3095 ppp->rcomp = cp;
3096 ppp->rc_state = state;
3097 ppp_recv_unlock(ppp);
3098 if (ostate) {
3099 ocomp->decomp_free(ostate);
3100 module_put(module: ocomp->owner);
3101 }
3102 err = 0;
3103 } else
3104 module_put(module: cp->owner);
3105 }
3106
3107 out:
3108 return err;
3109}
3110
3111/*
3112 * Look at a CCP packet and update our state accordingly.
3113 * We assume the caller has the xmit or recv path locked.
3114 */
3115static void
3116ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
3117{
3118 unsigned char *dp;
3119 int len;
3120
3121 if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
3122 return; /* no header */
3123 dp = skb->data + 2;
3124
3125 switch (CCP_CODE(dp)) {
3126 case CCP_CONFREQ:
3127
3128 /* A ConfReq starts negotiation of compression
3129 * in one direction of transmission,
3130 * and hence brings it down...but which way?
3131 *
3132 * Remember:
3133 * A ConfReq indicates what the sender would like to receive
3134 */
3135 if(inbound)
3136 /* He is proposing what I should send */
3137 ppp->xstate &= ~SC_COMP_RUN;
3138 else
3139 /* I am proposing to what he should send */
3140 ppp->rstate &= ~SC_DECOMP_RUN;
3141
3142 break;
3143
3144 case CCP_TERMREQ:
3145 case CCP_TERMACK:
3146 /*
3147 * CCP is going down, both directions of transmission
3148 */
3149 ppp->rstate &= ~SC_DECOMP_RUN;
3150 ppp->xstate &= ~SC_COMP_RUN;
3151 break;
3152
3153 case CCP_CONFACK:
3154 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
3155 break;
3156 len = CCP_LENGTH(dp);
3157 if (!pskb_may_pull(skb, len: len + 2))
3158 return; /* too short */
3159 dp += CCP_HDRLEN;
3160 len -= CCP_HDRLEN;
3161 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
3162 break;
3163 if (inbound) {
3164 /* we will start receiving compressed packets */
3165 if (!ppp->rc_state)
3166 break;
3167 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
3168 ppp->file.index, 0, ppp->mru, ppp->debug)) {
3169 ppp->rstate |= SC_DECOMP_RUN;
3170 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
3171 }
3172 } else {
3173 /* we will soon start sending compressed packets */
3174 if (!ppp->xc_state)
3175 break;
3176 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
3177 ppp->file.index, 0, ppp->debug))
3178 ppp->xstate |= SC_COMP_RUN;
3179 }
3180 break;
3181
3182 case CCP_RESETACK:
3183 /* reset the [de]compressor */
3184 if ((ppp->flags & SC_CCP_UP) == 0)
3185 break;
3186 if (inbound) {
3187 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
3188 ppp->rcomp->decomp_reset(ppp->rc_state);
3189 ppp->rstate &= ~SC_DC_ERROR;
3190 }
3191 } else {
3192 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
3193 ppp->xcomp->comp_reset(ppp->xc_state);
3194 }
3195 break;
3196 }
3197}
3198
3199/* Free up compression resources. */
3200static void
3201ppp_ccp_closed(struct ppp *ppp)
3202{
3203 void *xstate, *rstate;
3204 struct compressor *xcomp, *rcomp;
3205
3206 ppp_lock(ppp);
3207 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
3208 ppp->xstate = 0;
3209 xcomp = ppp->xcomp;
3210 xstate = ppp->xc_state;
3211 ppp->xc_state = NULL;
3212 ppp->rstate = 0;
3213 rcomp = ppp->rcomp;
3214 rstate = ppp->rc_state;
3215 ppp->rc_state = NULL;
3216 ppp_unlock(ppp);
3217
3218 if (xstate) {
3219 xcomp->comp_free(xstate);
3220 module_put(module: xcomp->owner);
3221 }
3222 if (rstate) {
3223 rcomp->decomp_free(rstate);
3224 module_put(module: rcomp->owner);
3225 }
3226}
3227
3228/* List of compressors. */
3229static LIST_HEAD(compressor_list);
3230static DEFINE_SPINLOCK(compressor_list_lock);
3231
3232struct compressor_entry {
3233 struct list_head list;
3234 struct compressor *comp;
3235};
3236
3237static struct compressor_entry *
3238find_comp_entry(int proto)
3239{
3240 struct compressor_entry *ce;
3241
3242 list_for_each_entry(ce, &compressor_list, list) {
3243 if (ce->comp->compress_proto == proto)
3244 return ce;
3245 }
3246 return NULL;
3247}
3248
3249/* Register a compressor */
3250int
3251ppp_register_compressor(struct compressor *cp)
3252{
3253 struct compressor_entry *ce;
3254 int ret;
3255 spin_lock(lock: &compressor_list_lock);
3256 ret = -EEXIST;
3257 if (find_comp_entry(proto: cp->compress_proto))
3258 goto out;
3259 ret = -ENOMEM;
3260 ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
3261 if (!ce)
3262 goto out;
3263 ret = 0;
3264 ce->comp = cp;
3265 list_add(new: &ce->list, head: &compressor_list);
3266 out:
3267 spin_unlock(lock: &compressor_list_lock);
3268 return ret;
3269}
3270
3271/* Unregister a compressor */
3272void
3273ppp_unregister_compressor(struct compressor *cp)
3274{
3275 struct compressor_entry *ce;
3276
3277 spin_lock(lock: &compressor_list_lock);
3278 ce = find_comp_entry(proto: cp->compress_proto);
3279 if (ce && ce->comp == cp) {
3280 list_del(entry: &ce->list);
3281 kfree(objp: ce);
3282 }
3283 spin_unlock(lock: &compressor_list_lock);
3284}
3285
3286/* Find a compressor. */
3287static struct compressor *
3288find_compressor(int type)
3289{
3290 struct compressor_entry *ce;
3291 struct compressor *cp = NULL;
3292
3293 spin_lock(lock: &compressor_list_lock);
3294 ce = find_comp_entry(proto: type);
3295 if (ce) {
3296 cp = ce->comp;
3297 if (!try_module_get(module: cp->owner))
3298 cp = NULL;
3299 }
3300 spin_unlock(lock: &compressor_list_lock);
3301 return cp;
3302}
3303
3304/*
3305 * Miscelleneous stuff.
3306 */
3307
3308static void
3309ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
3310{
3311 struct slcompress *vj = ppp->vj;
3312 int cpu;
3313
3314 memset(st, 0, sizeof(*st));
3315 for_each_possible_cpu(cpu) {
3316 struct pcpu_sw_netstats *p = per_cpu_ptr(ppp->dev->tstats, cpu);
3317 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
3318
3319 rx_packets = u64_stats_read(p: &p->rx_packets);
3320 rx_bytes = u64_stats_read(p: &p->rx_bytes);
3321 tx_packets = u64_stats_read(p: &p->tx_packets);
3322 tx_bytes = u64_stats_read(p: &p->tx_bytes);
3323
3324 st->p.ppp_ipackets += rx_packets;
3325 st->p.ppp_ibytes += rx_bytes;
3326 st->p.ppp_opackets += tx_packets;
3327 st->p.ppp_obytes += tx_bytes;
3328 }
3329 st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
3330 st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
3331 if (!vj)
3332 return;
3333 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
3334 st->vj.vjs_compressed = vj->sls_o_compressed;
3335 st->vj.vjs_searches = vj->sls_o_searches;
3336 st->vj.vjs_misses = vj->sls_o_misses;
3337 st->vj.vjs_errorin = vj->sls_i_error;
3338 st->vj.vjs_tossed = vj->sls_i_tossed;
3339 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
3340 st->vj.vjs_compressedin = vj->sls_i_compressed;
3341}
3342
3343/*
3344 * Stuff for handling the lists of ppp units and channels
3345 * and for initialization.
3346 */
3347
3348/*
3349 * Create a new ppp interface unit. Fails if it can't allocate memory
3350 * or if there is already a unit with the requested number.
3351 * unit == -1 means allocate a new number.
3352 */
3353static int ppp_create_interface(struct net *net, struct file *file, int *unit)
3354{
3355 struct ppp_config conf = {
3356 .file = file,
3357 .unit = *unit,
3358 .ifname_is_set = false,
3359 };
3360 struct net_device *dev;
3361 struct ppp *ppp;
3362 int err;
3363
3364 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup);
3365 if (!dev) {
3366 err = -ENOMEM;
3367 goto err;
3368 }
3369 dev_net_set(dev, net);
3370 dev->rtnl_link_ops = &ppp_link_ops;
3371
3372 rtnl_lock();
3373
3374 err = ppp_dev_configure(src_net: net, dev, conf: &conf);
3375 if (err < 0)
3376 goto err_dev;
3377 ppp = netdev_priv(dev);
3378 *unit = ppp->file.index;
3379
3380 rtnl_unlock();
3381
3382 return 0;
3383
3384err_dev:
3385 rtnl_unlock();
3386 free_netdev(dev);
3387err:
3388 return err;
3389}
3390
3391/*
3392 * Initialize a ppp_file structure.
3393 */
3394static void
3395init_ppp_file(struct ppp_file *pf, int kind)
3396{
3397 pf->kind = kind;
3398 skb_queue_head_init(list: &pf->xq);
3399 skb_queue_head_init(list: &pf->rq);
3400 refcount_set(r: &pf->refcnt, n: 1);
3401 init_waitqueue_head(&pf->rwait);
3402}
3403
3404/*
3405 * Free the memory used by a ppp unit. This is only called once
3406 * there are no channels connected to the unit and no file structs
3407 * that reference the unit.
3408 */
3409static void ppp_destroy_interface(struct ppp *ppp)
3410{
3411 atomic_dec(v: &ppp_unit_count);
3412
3413 if (!ppp->file.dead || ppp->n_channels) {
3414 /* "can't happen" */
3415 netdev_err(dev: ppp->dev, format: "ppp: destroying ppp struct %p "
3416 "but dead=%d n_channels=%d !\n",
3417 ppp, ppp->file.dead, ppp->n_channels);
3418 return;
3419 }
3420
3421 ppp_ccp_closed(ppp);
3422 if (ppp->vj) {
3423 slhc_free(comp: ppp->vj);
3424 ppp->vj = NULL;
3425 }
3426 skb_queue_purge(list: &ppp->file.xq);
3427 skb_queue_purge(list: &ppp->file.rq);
3428#ifdef CONFIG_PPP_MULTILINK
3429 skb_queue_purge(list: &ppp->mrq);
3430#endif /* CONFIG_PPP_MULTILINK */
3431#ifdef CONFIG_PPP_FILTER
3432 if (ppp->pass_filter) {
3433 bpf_prog_destroy(fp: ppp->pass_filter);
3434 ppp->pass_filter = NULL;
3435 }
3436
3437 if (ppp->active_filter) {
3438 bpf_prog_destroy(fp: ppp->active_filter);
3439 ppp->active_filter = NULL;
3440 }
3441#endif /* CONFIG_PPP_FILTER */
3442
3443 kfree_skb(skb: ppp->xmit_pending);
3444 free_percpu(pdata: ppp->xmit_recursion);
3445
3446 free_netdev(dev: ppp->dev);
3447}
3448
3449/*
3450 * Locate an existing ppp unit.
3451 * The caller should have locked the all_ppp_mutex.
3452 */
3453static struct ppp *
3454ppp_find_unit(struct ppp_net *pn, int unit)
3455{
3456 return unit_find(p: &pn->units_idr, n: unit);
3457}
3458
3459/*
3460 * Locate an existing ppp channel.
3461 * The caller should have locked the all_channels_lock.
3462 * First we look in the new_channels list, then in the
3463 * all_channels list. If found in the new_channels list,
3464 * we move it to the all_channels list. This is for speed
3465 * when we have a lot of channels in use.
3466 */
3467static struct channel *
3468ppp_find_channel(struct ppp_net *pn, int unit)
3469{
3470 struct channel *pch;
3471
3472 list_for_each_entry(pch, &pn->new_channels, list) {
3473 if (pch->file.index == unit) {
3474 list_move(list: &pch->list, head: &pn->all_channels);
3475 return pch;
3476 }
3477 }
3478
3479 list_for_each_entry(pch, &pn->all_channels, list) {
3480 if (pch->file.index == unit)
3481 return pch;
3482 }
3483
3484 return NULL;
3485}
3486
3487/*
3488 * Connect a PPP channel to a PPP interface unit.
3489 */
3490static int
3491ppp_connect_channel(struct channel *pch, int unit)
3492{
3493 struct ppp *ppp;
3494 struct ppp_net *pn;
3495 int ret = -ENXIO;
3496 int hdrlen;
3497
3498 pn = ppp_pernet(net: pch->chan_net);
3499
3500 mutex_lock(&pn->all_ppp_mutex);
3501 ppp = ppp_find_unit(pn, unit);
3502 if (!ppp)
3503 goto out;
3504 spin_lock(lock: &pch->upl);
3505 ret = -EINVAL;
3506 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
3507 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
3508 goto outl;
3509
3510 ppp_lock(ppp);
3511 spin_lock_bh(lock: &pch->downl);
3512 if (!pch->chan) {
3513 /* Don't connect unregistered channels */
3514 spin_unlock_bh(lock: &pch->downl);
3515 ppp_unlock(ppp);
3516 ret = -ENOTCONN;
3517 goto outl;
3518 }
3519 if (pch->chan->direct_xmit)
3520 ppp->dev->priv_flags |= IFF_NO_QUEUE;
3521 else
3522 ppp->dev->priv_flags &= ~IFF_NO_QUEUE;
3523 spin_unlock_bh(lock: &pch->downl);
3524 if (pch->file.hdrlen > ppp->file.hdrlen)
3525 ppp->file.hdrlen = pch->file.hdrlen;
3526 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
3527 if (hdrlen > ppp->dev->hard_header_len)
3528 ppp->dev->hard_header_len = hdrlen;
3529 list_add_tail_rcu(new: &pch->clist, head: &ppp->channels);
3530 ++ppp->n_channels;
3531 rcu_assign_pointer(pch->ppp, ppp);
3532 refcount_inc(r: &ppp->file.refcnt);
3533 ppp_unlock(ppp);
3534 ret = 0;
3535
3536 outl:
3537 spin_unlock(lock: &pch->upl);
3538 out:
3539 mutex_unlock(lock: &pn->all_ppp_mutex);
3540 return ret;
3541}
3542
3543/*
3544 * Disconnect a channel from its ppp unit.
3545 */
3546static int
3547ppp_disconnect_channel(struct channel *pch)
3548{
3549 struct ppp *ppp;
3550 int err = -EINVAL;
3551
3552 spin_lock(lock: &pch->upl);
3553 ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl));
3554 spin_unlock(lock: &pch->upl);
3555 if (ppp) {
3556 /* remove it from the ppp unit's list */
3557 ppp_lock(ppp);
3558 list_del_rcu(entry: &pch->clist);
3559 if (--ppp->n_channels == 0)
3560 wake_up_interruptible(&ppp->file.rwait);
3561 ppp_unlock(ppp);
3562 synchronize_net();
3563 if (refcount_dec_and_test(r: &ppp->file.refcnt))
3564 ppp_destroy_interface(ppp);
3565 err = 0;
3566 }
3567 return err;
3568}
3569
3570/*
3571 * Free up the resources used by a ppp channel.
3572 */
3573static void ppp_destroy_channel(struct channel *pch)
3574{
3575 put_net_track(net: pch->chan_net, tracker: &pch->ns_tracker);
3576 pch->chan_net = NULL;
3577
3578 atomic_dec(v: &channel_count);
3579
3580 if (!pch->file.dead) {
3581 /* "can't happen" */
3582 pr_err("ppp: destroying undead channel %p !\n", pch);
3583 return;
3584 }
3585 skb_queue_purge(list: &pch->file.xq);
3586 skb_queue_purge(list: &pch->file.rq);
3587 kfree(objp: pch);
3588}
3589
3590static void __exit ppp_cleanup(void)
3591{
3592 /* should never happen */
3593 if (atomic_read(v: &ppp_unit_count) || atomic_read(v: &channel_count))
3594 pr_err("PPP: removing module but units remain!\n");
3595 rtnl_link_unregister(ops: &ppp_link_ops);
3596 unregister_chrdev(PPP_MAJOR, name: "ppp");
3597 device_destroy(cls: &ppp_class, MKDEV(PPP_MAJOR, 0));
3598 class_unregister(class: &ppp_class);
3599 unregister_pernet_device(&ppp_net_ops);
3600}
3601
3602/*
3603 * Units handling. Caller must protect concurrent access
3604 * by holding all_ppp_mutex
3605 */
3606
3607/* associate pointer with specified number */
3608static int unit_set(struct idr *p, void *ptr, int n)
3609{
3610 int unit;
3611
3612 unit = idr_alloc(p, ptr, start: n, end: n + 1, GFP_KERNEL);
3613 if (unit == -ENOSPC)
3614 unit = -EINVAL;
3615 return unit;
3616}
3617
3618/* get new free unit number and associate pointer with it */
3619static int unit_get(struct idr *p, void *ptr, int min)
3620{
3621 return idr_alloc(p, ptr, start: min, end: 0, GFP_KERNEL);
3622}
3623
3624/* put unit number back to a pool */
3625static void unit_put(struct idr *p, int n)
3626{
3627 idr_remove(p, id: n);
3628}
3629
3630/* get pointer associated with the number */
3631static void *unit_find(struct idr *p, int n)
3632{
3633 return idr_find(p, id: n);
3634}
3635
3636/* Module/initialization stuff */
3637
3638module_init(ppp_init);
3639module_exit(ppp_cleanup);
3640
3641EXPORT_SYMBOL(ppp_register_net_channel);
3642EXPORT_SYMBOL(ppp_register_channel);
3643EXPORT_SYMBOL(ppp_unregister_channel);
3644EXPORT_SYMBOL(ppp_channel_index);
3645EXPORT_SYMBOL(ppp_unit_number);
3646EXPORT_SYMBOL(ppp_dev_name);
3647EXPORT_SYMBOL(ppp_input);
3648EXPORT_SYMBOL(ppp_input_error);
3649EXPORT_SYMBOL(ppp_output_wakeup);
3650EXPORT_SYMBOL(ppp_register_compressor);
3651EXPORT_SYMBOL(ppp_unregister_compressor);
3652MODULE_DESCRIPTION("Generic PPP layer driver");
3653MODULE_LICENSE("GPL");
3654MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
3655MODULE_ALIAS_RTNL_LINK("ppp");
3656MODULE_ALIAS("devname:ppp");
3657

source code of linux/drivers/net/ppp/ppp_generic.c