Root/drivers/net/ppp_generic.c

1/*
2 * Generic PPP layer for Linux.
3 *
4 * Copyright 1999-2002 Paul Mackerras.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * The generic PPP layer handles the PPP network interfaces, the
12 * /dev/ppp device, packet and VJ compression, and multilink.
13 * It talks to PPP `channels' via the interface defined in
14 * include/linux/ppp_channel.h. Channels provide the basic means for
15 * sending and receiving PPP frames on some kind of communications
16 * channel.
17 *
18 * Part of the code in this driver was inspired by the old async-only
19 * PPP driver, written by Michael Callahan and Al Longyear, and
20 * subsequently hacked by Paul Mackerras.
21 *
22 * ==FILEVERSION 20041108==
23 */
24
25#include <linux/module.h>
26#include <linux/kernel.h>
27#include <linux/kmod.h>
28#include <linux/init.h>
29#include <linux/list.h>
30#include <linux/idr.h>
31#include <linux/netdevice.h>
32#include <linux/poll.h>
33#include <linux/ppp_defs.h>
34#include <linux/filter.h>
35#include <linux/if_ppp.h>
36#include <linux/ppp_channel.h>
37#include <linux/ppp-comp.h>
38#include <linux/skbuff.h>
39#include <linux/rtnetlink.h>
40#include <linux/if_arp.h>
41#include <linux/ip.h>
42#include <linux/tcp.h>
43#include <linux/smp_lock.h>
44#include <linux/spinlock.h>
45#include <linux/rwsem.h>
46#include <linux/stddef.h>
47#include <linux/device.h>
48#include <linux/mutex.h>
49#include <net/slhc_vj.h>
50#include <asm/atomic.h>
51
52#include <linux/nsproxy.h>
53#include <net/net_namespace.h>
54#include <net/netns/generic.h>
55
56#define PPP_VERSION "2.4.2"
57
58/*
59 * Network protocols we support.
60 */
61#define NP_IP 0 /* Internet Protocol V4 */
62#define NP_IPV6 1 /* Internet Protocol V6 */
63#define NP_IPX 2 /* IPX protocol */
64#define NP_AT 3 /* Appletalk protocol */
65#define NP_MPLS_UC 4 /* MPLS unicast */
66#define NP_MPLS_MC 5 /* MPLS multicast */
67#define NUM_NP 6 /* Number of NPs. */
68
69#define MPHDRLEN 6 /* multilink protocol header length */
70#define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */
71#define MIN_FRAG_SIZE 64
72
73/*
74 * An instance of /dev/ppp can be associated with either a ppp
75 * interface unit or a ppp channel. In both cases, file->private_data
76 * points to one of these.
77 */
78struct ppp_file {
79    enum {
80        INTERFACE=1, CHANNEL
81    } kind;
82    struct sk_buff_head xq; /* pppd transmit queue */
83    struct sk_buff_head rq; /* receive queue for pppd */
84    wait_queue_head_t rwait; /* for poll on reading /dev/ppp */
85    atomic_t refcnt; /* # refs (incl /dev/ppp attached) */
86    int hdrlen; /* space to leave for headers */
87    int index; /* interface unit / channel number */
88    int dead; /* unit/channel has been shut down */
89};
90
91#define PF_TO_X(pf, X) container_of(pf, X, file)
92
93#define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp)
94#define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel)
95
96/*
97 * Data structure describing one ppp unit.
98 * A ppp unit corresponds to a ppp network interface device
99 * and represents a multilink bundle.
100 * It can have 0 or more ppp channels connected to it.
101 */
102struct ppp {
103    struct ppp_file file; /* stuff for read/write/poll 0 */
104    struct file *owner; /* file that owns this unit 48 */
105    struct list_head channels; /* list of attached channels 4c */
106    int n_channels; /* how many channels are attached 54 */
107    spinlock_t rlock; /* lock for receive side 58 */
108    spinlock_t wlock; /* lock for transmit side 5c */
109    int mru; /* max receive unit 60 */
110    unsigned int flags; /* control bits 64 */
111    unsigned int xstate; /* transmit state bits 68 */
112    unsigned int rstate; /* receive state bits 6c */
113    int debug; /* debug flags 70 */
114    struct slcompress *vj; /* state for VJ header compression */
115    enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */
116    struct sk_buff *xmit_pending; /* a packet ready to go out 88 */
117    struct compressor *xcomp; /* transmit packet compressor 8c */
118    void *xc_state; /* its internal state 90 */
119    struct compressor *rcomp; /* receive decompressor 94 */
120    void *rc_state; /* its internal state 98 */
121    unsigned long last_xmit; /* jiffies when last pkt sent 9c */
122    unsigned long last_recv; /* jiffies when last pkt rcvd a0 */
123    struct net_device *dev; /* network interface device a4 */
124    int closing; /* is device closing down? a8 */
125#ifdef CONFIG_PPP_MULTILINK
126    int nxchan; /* next channel to send something on */
127    u32 nxseq; /* next sequence number to send */
128    int mrru; /* MP: max reconst. receive unit */
129    u32 nextseq; /* MP: seq no of next packet */
130    u32 minseq; /* MP: min of most recent seqnos */
131    struct sk_buff_head mrq; /* MP: receive reconstruction queue */
132#endif /* CONFIG_PPP_MULTILINK */
133#ifdef CONFIG_PPP_FILTER
134    struct sock_filter *pass_filter; /* filter for packets to pass */
135    struct sock_filter *active_filter;/* filter for pkts to reset idle */
136    unsigned pass_len, active_len;
137#endif /* CONFIG_PPP_FILTER */
138    struct net *ppp_net; /* the net we belong to */
139};
140
141/*
142 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC,
143 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP,
144 * SC_MUST_COMP
145 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR.
146 * Bits in xstate: SC_COMP_RUN
147 */
148#define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \
149             |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \
150             |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP)
151
152/*
153 * Private data structure for each channel.
154 * This includes the data structure used for multilink.
155 */
156struct channel {
157    struct ppp_file file; /* stuff for read/write/poll */
158    struct list_head list; /* link in all/new_channels list */
159    struct ppp_channel *chan; /* public channel data structure */
160    struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */
161    spinlock_t downl; /* protects `chan', file.xq dequeue */
162    struct ppp *ppp; /* ppp unit we're connected to */
163    struct net *chan_net; /* the net channel belongs to */
164    struct list_head clist; /* link in list of channels per unit */
165    rwlock_t upl; /* protects `ppp' */
166#ifdef CONFIG_PPP_MULTILINK
167    u8 avail; /* flag used in multilink stuff */
168    u8 had_frag; /* >= 1 fragments have been sent */
169    u32 lastseq; /* MP: last sequence # received */
170    int speed; /* speed of the corresponding ppp channel*/
171#endif /* CONFIG_PPP_MULTILINK */
172};
173
174/*
175 * SMP locking issues:
176 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels
177 * list and the ppp.n_channels field, you need to take both locks
178 * before you modify them.
179 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock ->
180 * channel.downl.
181 */
182
183static atomic_t ppp_unit_count = ATOMIC_INIT(0);
184static atomic_t channel_count = ATOMIC_INIT(0);
185
186/* per-net private data for this module */
187static int ppp_net_id;
188struct ppp_net {
189    /* units to ppp mapping */
190    struct idr units_idr;
191
192    /*
193     * all_ppp_mutex protects the units_idr mapping.
194     * It also ensures that finding a ppp unit in the units_idr
195     * map and updating its file.refcnt field is atomic.
196     */
197    struct mutex all_ppp_mutex;
198
199    /* channels */
200    struct list_head all_channels;
201    struct list_head new_channels;
202    int last_channel_index;
203
204    /*
205     * all_channels_lock protects all_channels and
206     * last_channel_index, and the atomicity of find
207     * a channel and updating its file.refcnt field.
208     */
209    spinlock_t all_channels_lock;
210};
211
212/* Get the PPP protocol number from a skb */
213#define PPP_PROTO(skb) (((skb)->data[0] << 8) + (skb)->data[1])
214
215/* We limit the length of ppp->file.rq to this (arbitrary) value */
216#define PPP_MAX_RQLEN 32
217
218/*
219 * Maximum number of multilink fragments queued up.
220 * This has to be large enough to cope with the maximum latency of
221 * the slowest channel relative to the others. Strictly it should
222 * depend on the number of channels and their characteristics.
223 */
224#define PPP_MP_MAX_QLEN 128
225
226/* Multilink header bits. */
227#define B 0x80 /* this fragment begins a packet */
228#define E 0x40 /* this fragment ends a packet */
229
230/* Compare multilink sequence numbers (assumed to be 32 bits wide) */
231#define seq_before(a, b) ((s32)((a) - (b)) < 0)
232#define seq_after(a, b) ((s32)((a) - (b)) > 0)
233
234/* Prototypes. */
235static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
236            struct file *file, unsigned int cmd, unsigned long arg);
237static void ppp_xmit_process(struct ppp *ppp);
238static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
239static void ppp_push(struct ppp *ppp);
240static void ppp_channel_push(struct channel *pch);
241static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
242                  struct channel *pch);
243static void ppp_receive_error(struct ppp *ppp);
244static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb);
245static struct sk_buff *ppp_decompress_frame(struct ppp *ppp,
246                        struct sk_buff *skb);
247#ifdef CONFIG_PPP_MULTILINK
248static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb,
249                struct channel *pch);
250static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
251static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
252static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
253#endif /* CONFIG_PPP_MULTILINK */
254static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
255static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
256static void ppp_ccp_closed(struct ppp *ppp);
257static struct compressor *find_compressor(int type);
258static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
259static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
260static void init_ppp_file(struct ppp_file *pf, int kind);
261static void ppp_shutdown_interface(struct ppp *ppp);
262static void ppp_destroy_interface(struct ppp *ppp);
263static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit);
264static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
265static int ppp_connect_channel(struct channel *pch, int unit);
266static int ppp_disconnect_channel(struct channel *pch);
267static void ppp_destroy_channel(struct channel *pch);
268static int unit_get(struct idr *p, void *ptr);
269static int unit_set(struct idr *p, void *ptr, int n);
270static void unit_put(struct idr *p, int n);
271static void *unit_find(struct idr *p, int n);
272
273static struct class *ppp_class;
274
275/* per net-namespace data */
276static inline struct ppp_net *ppp_pernet(struct net *net)
277{
278    BUG_ON(!net);
279
280    return net_generic(net, ppp_net_id);
281}
282
283/* Translates a PPP protocol number to a NP index (NP == network protocol) */
284static inline int proto_to_npindex(int proto)
285{
286    switch (proto) {
287    case PPP_IP:
288        return NP_IP;
289    case PPP_IPV6:
290        return NP_IPV6;
291    case PPP_IPX:
292        return NP_IPX;
293    case PPP_AT:
294        return NP_AT;
295    case PPP_MPLS_UC:
296        return NP_MPLS_UC;
297    case PPP_MPLS_MC:
298        return NP_MPLS_MC;
299    }
300    return -EINVAL;
301}
302
303/* Translates an NP index into a PPP protocol number */
304static const int npindex_to_proto[NUM_NP] = {
305    PPP_IP,
306    PPP_IPV6,
307    PPP_IPX,
308    PPP_AT,
309    PPP_MPLS_UC,
310    PPP_MPLS_MC,
311};
312
313/* Translates an ethertype into an NP index */
314static inline int ethertype_to_npindex(int ethertype)
315{
316    switch (ethertype) {
317    case ETH_P_IP:
318        return NP_IP;
319    case ETH_P_IPV6:
320        return NP_IPV6;
321    case ETH_P_IPX:
322        return NP_IPX;
323    case ETH_P_PPPTALK:
324    case ETH_P_ATALK:
325        return NP_AT;
326    case ETH_P_MPLS_UC:
327        return NP_MPLS_UC;
328    case ETH_P_MPLS_MC:
329        return NP_MPLS_MC;
330    }
331    return -1;
332}
333
334/* Translates an NP index into an ethertype */
335static const int npindex_to_ethertype[NUM_NP] = {
336    ETH_P_IP,
337    ETH_P_IPV6,
338    ETH_P_IPX,
339    ETH_P_PPPTALK,
340    ETH_P_MPLS_UC,
341    ETH_P_MPLS_MC,
342};
343
344/*
345 * Locking shorthand.
346 */
347#define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock)
348#define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock)
349#define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock)
350#define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock)
351#define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \
352                     ppp_recv_lock(ppp); } while (0)
353#define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \
354                     ppp_xmit_unlock(ppp); } while (0)
355
356/*
357 * /dev/ppp device routines.
358 * The /dev/ppp device is used by pppd to control the ppp unit.
359 * It supports the read, write, ioctl and poll functions.
360 * Open instances of /dev/ppp can be in one of three states:
361 * unattached, attached to a ppp unit, or attached to a ppp channel.
362 */
363static int ppp_open(struct inode *inode, struct file *file)
364{
365    cycle_kernel_lock();
366    /*
367     * This could (should?) be enforced by the permissions on /dev/ppp.
368     */
369    if (!capable(CAP_NET_ADMIN))
370        return -EPERM;
371    return 0;
372}
373
374static int ppp_release(struct inode *unused, struct file *file)
375{
376    struct ppp_file *pf = file->private_data;
377    struct ppp *ppp;
378
379    if (pf) {
380        file->private_data = NULL;
381        if (pf->kind == INTERFACE) {
382            ppp = PF_TO_PPP(pf);
383            if (file == ppp->owner)
384                ppp_shutdown_interface(ppp);
385        }
386        if (atomic_dec_and_test(&pf->refcnt)) {
387            switch (pf->kind) {
388            case INTERFACE:
389                ppp_destroy_interface(PF_TO_PPP(pf));
390                break;
391            case CHANNEL:
392                ppp_destroy_channel(PF_TO_CHANNEL(pf));
393                break;
394            }
395        }
396    }
397    return 0;
398}
399
400static ssize_t ppp_read(struct file *file, char __user *buf,
401            size_t count, loff_t *ppos)
402{
403    struct ppp_file *pf = file->private_data;
404    DECLARE_WAITQUEUE(wait, current);
405    ssize_t ret;
406    struct sk_buff *skb = NULL;
407
408    ret = count;
409
410    if (!pf)
411        return -ENXIO;
412    add_wait_queue(&pf->rwait, &wait);
413    for (;;) {
414        set_current_state(TASK_INTERRUPTIBLE);
415        skb = skb_dequeue(&pf->rq);
416        if (skb)
417            break;
418        ret = 0;
419        if (pf->dead)
420            break;
421        if (pf->kind == INTERFACE) {
422            /*
423             * Return 0 (EOF) on an interface that has no
424             * channels connected, unless it is looping
425             * network traffic (demand mode).
426             */
427            struct ppp *ppp = PF_TO_PPP(pf);
428            if (ppp->n_channels == 0
429                && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
430                break;
431        }
432        ret = -EAGAIN;
433        if (file->f_flags & O_NONBLOCK)
434            break;
435        ret = -ERESTARTSYS;
436        if (signal_pending(current))
437            break;
438        schedule();
439    }
440    set_current_state(TASK_RUNNING);
441    remove_wait_queue(&pf->rwait, &wait);
442
443    if (!skb)
444        goto out;
445
446    ret = -EOVERFLOW;
447    if (skb->len > count)
448        goto outf;
449    ret = -EFAULT;
450    if (copy_to_user(buf, skb->data, skb->len))
451        goto outf;
452    ret = skb->len;
453
454 outf:
455    kfree_skb(skb);
456 out:
457    return ret;
458}
459
460static ssize_t ppp_write(struct file *file, const char __user *buf,
461             size_t count, loff_t *ppos)
462{
463    struct ppp_file *pf = file->private_data;
464    struct sk_buff *skb;
465    ssize_t ret;
466
467    if (!pf)
468        return -ENXIO;
469    ret = -ENOMEM;
470    skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
471    if (!skb)
472        goto out;
473    skb_reserve(skb, pf->hdrlen);
474    ret = -EFAULT;
475    if (copy_from_user(skb_put(skb, count), buf, count)) {
476        kfree_skb(skb);
477        goto out;
478    }
479
480    skb_queue_tail(&pf->xq, skb);
481
482    switch (pf->kind) {
483    case INTERFACE:
484        ppp_xmit_process(PF_TO_PPP(pf));
485        break;
486    case CHANNEL:
487        ppp_channel_push(PF_TO_CHANNEL(pf));
488        break;
489    }
490
491    ret = count;
492
493 out:
494    return ret;
495}
496
497/* No kernel lock - fine */
498static unsigned int ppp_poll(struct file *file, poll_table *wait)
499{
500    struct ppp_file *pf = file->private_data;
501    unsigned int mask;
502
503    if (!pf)
504        return 0;
505    poll_wait(file, &pf->rwait, wait);
506    mask = POLLOUT | POLLWRNORM;
507    if (skb_peek(&pf->rq))
508        mask |= POLLIN | POLLRDNORM;
509    if (pf->dead)
510        mask |= POLLHUP;
511    else if (pf->kind == INTERFACE) {
512        /* see comment in ppp_read */
513        struct ppp *ppp = PF_TO_PPP(pf);
514        if (ppp->n_channels == 0
515            && (ppp->flags & SC_LOOP_TRAFFIC) == 0)
516            mask |= POLLIN | POLLRDNORM;
517    }
518
519    return mask;
520}
521
522#ifdef CONFIG_PPP_FILTER
523static int get_filter(void __user *arg, struct sock_filter **p)
524{
525    struct sock_fprog uprog;
526    struct sock_filter *code = NULL;
527    int len, err;
528
529    if (copy_from_user(&uprog, arg, sizeof(uprog)))
530        return -EFAULT;
531
532    if (!uprog.len) {
533        *p = NULL;
534        return 0;
535    }
536
537    len = uprog.len * sizeof(struct sock_filter);
538    code = kmalloc(len, GFP_KERNEL);
539    if (code == NULL)
540        return -ENOMEM;
541
542    if (copy_from_user(code, uprog.filter, len)) {
543        kfree(code);
544        return -EFAULT;
545    }
546
547    err = sk_chk_filter(code, uprog.len);
548    if (err) {
549        kfree(code);
550        return err;
551    }
552
553    *p = code;
554    return uprog.len;
555}
556#endif /* CONFIG_PPP_FILTER */
557
558static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
559{
560    struct ppp_file *pf = file->private_data;
561    struct ppp *ppp;
562    int err = -EFAULT, val, val2, i;
563    struct ppp_idle idle;
564    struct npioctl npi;
565    int unit, cflags;
566    struct slcompress *vj;
567    void __user *argp = (void __user *)arg;
568    int __user *p = argp;
569
570    if (!pf)
571        return ppp_unattached_ioctl(current->nsproxy->net_ns,
572                    pf, file, cmd, arg);
573
574    if (cmd == PPPIOCDETACH) {
575        /*
576         * We have to be careful here... if the file descriptor
577         * has been dup'd, we could have another process in the
578         * middle of a poll using the same file *, so we had
579         * better not free the interface data structures -
580         * instead we fail the ioctl. Even in this case, we
581         * shut down the interface if we are the owner of it.
582         * Actually, we should get rid of PPPIOCDETACH, userland
583         * (i.e. pppd) could achieve the same effect by closing
584         * this fd and reopening /dev/ppp.
585         */
586        err = -EINVAL;
587        lock_kernel();
588        if (pf->kind == INTERFACE) {
589            ppp = PF_TO_PPP(pf);
590            if (file == ppp->owner)
591                ppp_shutdown_interface(ppp);
592        }
593        if (atomic_long_read(&file->f_count) <= 2) {
594            ppp_release(NULL, file);
595            err = 0;
596        } else
597            printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%ld\n",
598                   atomic_long_read(&file->f_count));
599        unlock_kernel();
600        return err;
601    }
602
603    if (pf->kind == CHANNEL) {
604        struct channel *pch;
605        struct ppp_channel *chan;
606
607        lock_kernel();
608        pch = PF_TO_CHANNEL(pf);
609
610        switch (cmd) {
611        case PPPIOCCONNECT:
612            if (get_user(unit, p))
613                break;
614            err = ppp_connect_channel(pch, unit);
615            break;
616
617        case PPPIOCDISCONN:
618            err = ppp_disconnect_channel(pch);
619            break;
620
621        default:
622            down_read(&pch->chan_sem);
623            chan = pch->chan;
624            err = -ENOTTY;
625            if (chan && chan->ops->ioctl)
626                err = chan->ops->ioctl(chan, cmd, arg);
627            up_read(&pch->chan_sem);
628        }
629        unlock_kernel();
630        return err;
631    }
632
633    if (pf->kind != INTERFACE) {
634        /* can't happen */
635        printk(KERN_ERR "PPP: not interface or channel??\n");
636        return -EINVAL;
637    }
638
639    lock_kernel();
640    ppp = PF_TO_PPP(pf);
641    switch (cmd) {
642    case PPPIOCSMRU:
643        if (get_user(val, p))
644            break;
645        ppp->mru = val;
646        err = 0;
647        break;
648
649    case PPPIOCSFLAGS:
650        if (get_user(val, p))
651            break;
652        ppp_lock(ppp);
653        cflags = ppp->flags & ~val;
654        ppp->flags = val & SC_FLAG_BITS;
655        ppp_unlock(ppp);
656        if (cflags & SC_CCP_OPEN)
657            ppp_ccp_closed(ppp);
658        err = 0;
659        break;
660
661    case PPPIOCGFLAGS:
662        val = ppp->flags | ppp->xstate | ppp->rstate;
663        if (put_user(val, p))
664            break;
665        err = 0;
666        break;
667
668    case PPPIOCSCOMPRESS:
669        err = ppp_set_compress(ppp, arg);
670        break;
671
672    case PPPIOCGUNIT:
673        if (put_user(ppp->file.index, p))
674            break;
675        err = 0;
676        break;
677
678    case PPPIOCSDEBUG:
679        if (get_user(val, p))
680            break;
681        ppp->debug = val;
682        err = 0;
683        break;
684
685    case PPPIOCGDEBUG:
686        if (put_user(ppp->debug, p))
687            break;
688        err = 0;
689        break;
690
691    case PPPIOCGIDLE:
692        idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
693        idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
694        if (copy_to_user(argp, &idle, sizeof(idle)))
695            break;
696        err = 0;
697        break;
698
699    case PPPIOCSMAXCID:
700        if (get_user(val, p))
701            break;
702        val2 = 15;
703        if ((val >> 16) != 0) {
704            val2 = val >> 16;
705            val &= 0xffff;
706        }
707        vj = slhc_init(val2+1, val+1);
708        if (!vj) {
709            printk(KERN_ERR "PPP: no memory (VJ compressor)\n");
710            err = -ENOMEM;
711            break;
712        }
713        ppp_lock(ppp);
714        if (ppp->vj)
715            slhc_free(ppp->vj);
716        ppp->vj = vj;
717        ppp_unlock(ppp);
718        err = 0;
719        break;
720
721    case PPPIOCGNPMODE:
722    case PPPIOCSNPMODE:
723        if (copy_from_user(&npi, argp, sizeof(npi)))
724            break;
725        err = proto_to_npindex(npi.protocol);
726        if (err < 0)
727            break;
728        i = err;
729        if (cmd == PPPIOCGNPMODE) {
730            err = -EFAULT;
731            npi.mode = ppp->npmode[i];
732            if (copy_to_user(argp, &npi, sizeof(npi)))
733                break;
734        } else {
735            ppp->npmode[i] = npi.mode;
736            /* we may be able to transmit more packets now (??) */
737            netif_wake_queue(ppp->dev);
738        }
739        err = 0;
740        break;
741
742#ifdef CONFIG_PPP_FILTER
743    case PPPIOCSPASS:
744    {
745        struct sock_filter *code;
746        err = get_filter(argp, &code);
747        if (err >= 0) {
748            ppp_lock(ppp);
749            kfree(ppp->pass_filter);
750            ppp->pass_filter = code;
751            ppp->pass_len = err;
752            ppp_unlock(ppp);
753            err = 0;
754        }
755        break;
756    }
757    case PPPIOCSACTIVE:
758    {
759        struct sock_filter *code;
760        err = get_filter(argp, &code);
761        if (err >= 0) {
762            ppp_lock(ppp);
763            kfree(ppp->active_filter);
764            ppp->active_filter = code;
765            ppp->active_len = err;
766            ppp_unlock(ppp);
767            err = 0;
768        }
769        break;
770    }
771#endif /* CONFIG_PPP_FILTER */
772
773#ifdef CONFIG_PPP_MULTILINK
774    case PPPIOCSMRRU:
775        if (get_user(val, p))
776            break;
777        ppp_recv_lock(ppp);
778        ppp->mrru = val;
779        ppp_recv_unlock(ppp);
780        err = 0;
781        break;
782#endif /* CONFIG_PPP_MULTILINK */
783
784    default:
785        err = -ENOTTY;
786    }
787    unlock_kernel();
788    return err;
789}
790
791static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
792            struct file *file, unsigned int cmd, unsigned long arg)
793{
794    int unit, err = -EFAULT;
795    struct ppp *ppp;
796    struct channel *chan;
797    struct ppp_net *pn;
798    int __user *p = (int __user *)arg;
799
800    lock_kernel();
801    switch (cmd) {
802    case PPPIOCNEWUNIT:
803        /* Create a new ppp unit */
804        if (get_user(unit, p))
805            break;
806        ppp = ppp_create_interface(net, unit, &err);
807        if (!ppp)
808            break;
809        file->private_data = &ppp->file;
810        ppp->owner = file;
811        err = -EFAULT;
812        if (put_user(ppp->file.index, p))
813            break;
814        err = 0;
815        break;
816
817    case PPPIOCATTACH:
818        /* Attach to an existing ppp unit */
819        if (get_user(unit, p))
820            break;
821        err = -ENXIO;
822        pn = ppp_pernet(net);
823        mutex_lock(&pn->all_ppp_mutex);
824        ppp = ppp_find_unit(pn, unit);
825        if (ppp) {
826            atomic_inc(&ppp->file.refcnt);
827            file->private_data = &ppp->file;
828            err = 0;
829        }
830        mutex_unlock(&pn->all_ppp_mutex);
831        break;
832
833    case PPPIOCATTCHAN:
834        if (get_user(unit, p))
835            break;
836        err = -ENXIO;
837        pn = ppp_pernet(net);
838        spin_lock_bh(&pn->all_channels_lock);
839        chan = ppp_find_channel(pn, unit);
840        if (chan) {
841            atomic_inc(&chan->file.refcnt);
842            file->private_data = &chan->file;
843            err = 0;
844        }
845        spin_unlock_bh(&pn->all_channels_lock);
846        break;
847
848    default:
849        err = -ENOTTY;
850    }
851    unlock_kernel();
852    return err;
853}
854
855static const struct file_operations ppp_device_fops = {
856    .owner = THIS_MODULE,
857    .read = ppp_read,
858    .write = ppp_write,
859    .poll = ppp_poll,
860    .unlocked_ioctl = ppp_ioctl,
861    .open = ppp_open,
862    .release = ppp_release
863};
864
865static __net_init int ppp_init_net(struct net *net)
866{
867    struct ppp_net *pn;
868    int err;
869
870    pn = kzalloc(sizeof(*pn), GFP_KERNEL);
871    if (!pn)
872        return -ENOMEM;
873
874    idr_init(&pn->units_idr);
875    mutex_init(&pn->all_ppp_mutex);
876
877    INIT_LIST_HEAD(&pn->all_channels);
878    INIT_LIST_HEAD(&pn->new_channels);
879
880    spin_lock_init(&pn->all_channels_lock);
881
882    err = net_assign_generic(net, ppp_net_id, pn);
883    if (err) {
884        kfree(pn);
885        return err;
886    }
887
888    return 0;
889}
890
891static __net_exit void ppp_exit_net(struct net *net)
892{
893    struct ppp_net *pn;
894
895    pn = net_generic(net, ppp_net_id);
896    idr_destroy(&pn->units_idr);
897    /*
898     * if someone has cached our net then
899     * further net_generic call will return NULL
900     */
901    net_assign_generic(net, ppp_net_id, NULL);
902    kfree(pn);
903}
904
905static struct pernet_operations ppp_net_ops = {
906    .init = ppp_init_net,
907    .exit = ppp_exit_net,
908};
909
910#define PPP_MAJOR 108
911
912/* Called at boot time if ppp is compiled into the kernel,
913   or at module load time (from init_module) if compiled as a module. */
914static int __init ppp_init(void)
915{
916    int err;
917
918    printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
919
920    err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
921    if (err) {
922        printk(KERN_ERR "failed to register PPP pernet device (%d)\n", err);
923        goto out;
924    }
925
926    err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
927    if (err) {
928        printk(KERN_ERR "failed to register PPP device (%d)\n", err);
929        goto out_net;
930    }
931
932    ppp_class = class_create(THIS_MODULE, "ppp");
933    if (IS_ERR(ppp_class)) {
934        err = PTR_ERR(ppp_class);
935        goto out_chrdev;
936    }
937
938    /* not a big deal if we fail here :-) */
939    device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
940
941    return 0;
942
943out_chrdev:
944    unregister_chrdev(PPP_MAJOR, "ppp");
945out_net:
946    unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
947out:
948    return err;
949}
950
951/*
952 * Network interface unit routines.
953 */
954static int
955ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
956{
957    struct ppp *ppp = netdev_priv(dev);
958    int npi, proto;
959    unsigned char *pp;
960
961    npi = ethertype_to_npindex(ntohs(skb->protocol));
962    if (npi < 0)
963        goto outf;
964
965    /* Drop, accept or reject the packet */
966    switch (ppp->npmode[npi]) {
967    case NPMODE_PASS:
968        break;
969    case NPMODE_QUEUE:
970        /* it would be nice to have a way to tell the network
971           system to queue this one up for later. */
972        goto outf;
973    case NPMODE_DROP:
974    case NPMODE_ERROR:
975        goto outf;
976    }
977
978    /* Put the 2-byte PPP protocol number on the front,
979       making sure there is room for the address and control fields. */
980    if (skb_cow_head(skb, PPP_HDRLEN))
981        goto outf;
982
983    pp = skb_push(skb, 2);
984    proto = npindex_to_proto[npi];
985    pp[0] = proto >> 8;
986    pp[1] = proto;
987
988    netif_stop_queue(dev);
989    skb_queue_tail(&ppp->file.xq, skb);
990    ppp_xmit_process(ppp);
991    return 0;
992
993 outf:
994    kfree_skb(skb);
995    ++dev->stats.tx_dropped;
996    return 0;
997}
998
999static int
1000ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1001{
1002    struct ppp *ppp = netdev_priv(dev);
1003    int err = -EFAULT;
1004    void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
1005    struct ppp_stats stats;
1006    struct ppp_comp_stats cstats;
1007    char *vers;
1008
1009    switch (cmd) {
1010    case SIOCGPPPSTATS:
1011        ppp_get_stats(ppp, &stats);
1012        if (copy_to_user(addr, &stats, sizeof(stats)))
1013            break;
1014        err = 0;
1015        break;
1016
1017    case SIOCGPPPCSTATS:
1018        memset(&cstats, 0, sizeof(cstats));
1019        if (ppp->xc_state)
1020            ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c);
1021        if (ppp->rc_state)
1022            ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d);
1023        if (copy_to_user(addr, &cstats, sizeof(cstats)))
1024            break;
1025        err = 0;
1026        break;
1027
1028    case SIOCGPPPVER:
1029        vers = PPP_VERSION;
1030        if (copy_to_user(addr, vers, strlen(vers) + 1))
1031            break;
1032        err = 0;
1033        break;
1034
1035    default:
1036        err = -EINVAL;
1037    }
1038
1039    return err;
1040}
1041
1042static const struct net_device_ops ppp_netdev_ops = {
1043    .ndo_start_xmit = ppp_start_xmit,
1044    .ndo_do_ioctl = ppp_net_ioctl,
1045};
1046
1047static void ppp_setup(struct net_device *dev)
1048{
1049    dev->netdev_ops = &ppp_netdev_ops;
1050    dev->hard_header_len = PPP_HDRLEN;
1051    dev->mtu = PPP_MTU;
1052    dev->addr_len = 0;
1053    dev->tx_queue_len = 3;
1054    dev->type = ARPHRD_PPP;
1055    dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
1056    dev->features |= NETIF_F_NETNS_LOCAL;
1057    dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1058}
1059
1060/*
1061 * Transmit-side routines.
1062 */
1063
1064/*
1065 * Called to do any work queued up on the transmit side
1066 * that can now be done.
1067 */
1068static void
1069ppp_xmit_process(struct ppp *ppp)
1070{
1071    struct sk_buff *skb;
1072
1073    ppp_xmit_lock(ppp);
1074    if (!ppp->closing) {
1075        ppp_push(ppp);
1076        while (!ppp->xmit_pending
1077               && (skb = skb_dequeue(&ppp->file.xq)))
1078            ppp_send_frame(ppp, skb);
1079        /* If there's no work left to do, tell the core net
1080           code that we can accept some more. */
1081        if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
1082            netif_wake_queue(ppp->dev);
1083    }
1084    ppp_xmit_unlock(ppp);
1085}
1086
1087static inline struct sk_buff *
1088pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
1089{
1090    struct sk_buff *new_skb;
1091    int len;
1092    int new_skb_size = ppp->dev->mtu +
1093        ppp->xcomp->comp_extra + ppp->dev->hard_header_len;
1094    int compressor_skb_size = ppp->dev->mtu +
1095        ppp->xcomp->comp_extra + PPP_HDRLEN;
1096    new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
1097    if (!new_skb) {
1098        if (net_ratelimit())
1099            printk(KERN_ERR "PPP: no memory (comp pkt)\n");
1100        return NULL;
1101    }
1102    if (ppp->dev->hard_header_len > PPP_HDRLEN)
1103        skb_reserve(new_skb,
1104                ppp->dev->hard_header_len - PPP_HDRLEN);
1105
1106    /* compressor still expects A/C bytes in hdr */
1107    len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
1108                   new_skb->data, skb->len + 2,
1109                   compressor_skb_size);
1110    if (len > 0 && (ppp->flags & SC_CCP_UP)) {
1111        kfree_skb(skb);
1112        skb = new_skb;
1113        skb_put(skb, len);
1114        skb_pull(skb, 2); /* pull off A/C bytes */
1115    } else if (len == 0) {
1116        /* didn't compress, or CCP not up yet */
1117        kfree_skb(new_skb);
1118        new_skb = skb;
1119    } else {
1120        /*
1121         * (len < 0)
1122         * MPPE requires that we do not send unencrypted
1123         * frames. The compressor will return -1 if we
1124         * should drop the frame. We cannot simply test
1125         * the compress_proto because MPPE and MPPC share
1126         * the same number.
1127         */
1128        if (net_ratelimit())
1129            printk(KERN_ERR "ppp: compressor dropped pkt\n");
1130        kfree_skb(skb);
1131        kfree_skb(new_skb);
1132        new_skb = NULL;
1133    }
1134    return new_skb;
1135}
1136
1137/*
1138 * Compress and send a frame.
1139 * The caller should have locked the xmit path,
1140 * and xmit_pending should be 0.
1141 */
1142static void
1143ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
1144{
1145    int proto = PPP_PROTO(skb);
1146    struct sk_buff *new_skb;
1147    int len;
1148    unsigned char *cp;
1149
1150    if (proto < 0x8000) {
1151#ifdef CONFIG_PPP_FILTER
1152        /* check if we should pass this packet */
1153        /* the filter instructions are constructed assuming
1154           a four-byte PPP header on each packet */
1155        *skb_push(skb, 2) = 1;
1156        if (ppp->pass_filter
1157            && sk_run_filter(skb, ppp->pass_filter,
1158                     ppp->pass_len) == 0) {
1159            if (ppp->debug & 1)
1160                printk(KERN_DEBUG "PPP: outbound frame not passed\n");
1161            kfree_skb(skb);
1162            return;
1163        }
1164        /* if this packet passes the active filter, record the time */
1165        if (!(ppp->active_filter
1166              && sk_run_filter(skb, ppp->active_filter,
1167                       ppp->active_len) == 0))
1168            ppp->last_xmit = jiffies;
1169        skb_pull(skb, 2);
1170#else
1171        /* for data packets, record the time */
1172        ppp->last_xmit = jiffies;
1173#endif /* CONFIG_PPP_FILTER */
1174    }
1175
1176    ++ppp->dev->stats.tx_packets;
1177    ppp->dev->stats.tx_bytes += skb->len - 2;
1178
1179    switch (proto) {
1180    case PPP_IP:
1181        if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0)
1182            break;
1183        /* try to do VJ TCP header compression */
1184        new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2,
1185                    GFP_ATOMIC);
1186        if (!new_skb) {
1187            printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n");
1188            goto drop;
1189        }
1190        skb_reserve(new_skb, ppp->dev->hard_header_len - 2);
1191        cp = skb->data + 2;
1192        len = slhc_compress(ppp->vj, cp, skb->len - 2,
1193                    new_skb->data + 2, &cp,
1194                    !(ppp->flags & SC_NO_TCP_CCID));
1195        if (cp == skb->data + 2) {
1196            /* didn't compress */
1197            kfree_skb(new_skb);
1198        } else {
1199            if (cp[0] & SL_TYPE_COMPRESSED_TCP) {
1200                proto = PPP_VJC_COMP;
1201                cp[0] &= ~SL_TYPE_COMPRESSED_TCP;
1202            } else {
1203                proto = PPP_VJC_UNCOMP;
1204                cp[0] = skb->data[2];
1205            }
1206            kfree_skb(skb);
1207            skb = new_skb;
1208            cp = skb_put(skb, len + 2);
1209            cp[0] = 0;
1210            cp[1] = proto;
1211        }
1212        break;
1213
1214    case PPP_CCP:
1215        /* peek at outbound CCP frames */
1216        ppp_ccp_peek(ppp, skb, 0);
1217        break;
1218    }
1219
1220    /* try to do packet compression */
1221    if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state
1222        && proto != PPP_LCP && proto != PPP_CCP) {
1223        if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) {
1224            if (net_ratelimit())
1225                printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n");
1226            goto drop;
1227        }
1228        skb = pad_compress_skb(ppp, skb);
1229        if (!skb)
1230            goto drop;
1231    }
1232
1233    /*
1234     * If we are waiting for traffic (demand dialling),
1235     * queue it up for pppd to receive.
1236     */
1237    if (ppp->flags & SC_LOOP_TRAFFIC) {
1238        if (ppp->file.rq.qlen > PPP_MAX_RQLEN)
1239            goto drop;
1240        skb_queue_tail(&ppp->file.rq, skb);
1241        wake_up_interruptible(&ppp->file.rwait);
1242        return;
1243    }
1244
1245    ppp->xmit_pending = skb;
1246    ppp_push(ppp);
1247    return;
1248
1249 drop:
1250    kfree_skb(skb);
1251    ++ppp->dev->stats.tx_errors;
1252}
1253
1254/*
1255 * Try to send the frame in xmit_pending.
1256 * The caller should have the xmit path locked.
1257 */
1258static void
1259ppp_push(struct ppp *ppp)
1260{
1261    struct list_head *list;
1262    struct channel *pch;
1263    struct sk_buff *skb = ppp->xmit_pending;
1264
1265    if (!skb)
1266        return;
1267
1268    list = &ppp->channels;
1269    if (list_empty(list)) {
1270        /* nowhere to send the packet, just drop it */
1271        ppp->xmit_pending = NULL;
1272        kfree_skb(skb);
1273        return;
1274    }
1275
1276    if ((ppp->flags & SC_MULTILINK) == 0) {
1277        /* not doing multilink: send it down the first channel */
1278        list = list->next;
1279        pch = list_entry(list, struct channel, clist);
1280
1281        spin_lock_bh(&pch->downl);
1282        if (pch->chan) {
1283            if (pch->chan->ops->start_xmit(pch->chan, skb))
1284                ppp->xmit_pending = NULL;
1285        } else {
1286            /* channel got unregistered */
1287            kfree_skb(skb);
1288            ppp->xmit_pending = NULL;
1289        }
1290        spin_unlock_bh(&pch->downl);
1291        return;
1292    }
1293
1294#ifdef CONFIG_PPP_MULTILINK
1295    /* Multilink: fragment the packet over as many links
1296       as can take the packet at the moment. */
1297    if (!ppp_mp_explode(ppp, skb))
1298        return;
1299#endif /* CONFIG_PPP_MULTILINK */
1300
1301    ppp->xmit_pending = NULL;
1302    kfree_skb(skb);
1303}
1304
1305#ifdef CONFIG_PPP_MULTILINK
1306/*
1307 * Divide a packet to be transmitted into fragments and
1308 * send them out the individual links.
1309 */
1310static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
1311{
1312    int len, totlen;
1313    int i, bits, hdrlen, mtu;
1314    int flen;
1315    int navail, nfree, nzero;
1316    int nbigger;
1317    int totspeed;
1318    int totfree;
1319    unsigned char *p, *q;
1320    struct list_head *list;
1321    struct channel *pch;
1322    struct sk_buff *frag;
1323    struct ppp_channel *chan;
1324
1325    totspeed = 0; /*total bitrate of the bundle*/
1326    nfree = 0; /* # channels which have no packet already queued */
1327    navail = 0; /* total # of usable channels (not deregistered) */
1328    nzero = 0; /* number of channels with zero speed associated*/
1329    totfree = 0; /*total # of channels available and
1330                  *having no queued packets before
1331                  *starting the fragmentation*/
1332
1333    hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1334    i = 0;
1335    list_for_each_entry(pch, &ppp->channels, clist) {
1336        navail += pch->avail = (pch->chan != NULL);
1337        pch->speed = pch->chan->speed;
1338        if (pch->avail) {
1339            if (skb_queue_empty(&pch->file.xq) ||
1340                !pch->had_frag) {
1341                    if (pch->speed == 0)
1342                        nzero++;
1343                    else
1344                        totspeed += pch->speed;
1345
1346                    pch->avail = 2;
1347                    ++nfree;
1348                    ++totfree;
1349                }
1350            if (!pch->had_frag && i < ppp->nxchan)
1351                ppp->nxchan = i;
1352        }
1353        ++i;
1354    }
1355    /*
1356     * Don't start sending this packet unless at least half of
1357     * the channels are free. This gives much better TCP
1358     * performance if we have a lot of channels.
1359     */
1360    if (nfree == 0 || nfree < navail / 2)
1361        return 0; /* can't take now, leave it in xmit_pending */
1362
1363    /* Do protocol field compression (XXX this should be optional) */
1364    p = skb->data;
1365    len = skb->len;
1366    if (*p == 0) {
1367        ++p;
1368        --len;
1369    }
1370
1371    totlen = len;
1372    nbigger = len % nfree;
1373
1374    /* skip to the channel after the one we last used
1375       and start at that one */
1376    list = &ppp->channels;
1377    for (i = 0; i < ppp->nxchan; ++i) {
1378        list = list->next;
1379        if (list == &ppp->channels) {
1380            i = 0;
1381            break;
1382        }
1383    }
1384
1385    /* create a fragment for each channel */
1386    bits = B;
1387    while (len > 0) {
1388        list = list->next;
1389        if (list == &ppp->channels) {
1390            i = 0;
1391            continue;
1392        }
1393        pch = list_entry(list, struct channel, clist);
1394        ++i;
1395        if (!pch->avail)
1396            continue;
1397
1398        /*
1399         * Skip this channel if it has a fragment pending already and
1400         * we haven't given a fragment to all of the free channels.
1401         */
1402        if (pch->avail == 1) {
1403            if (nfree > 0)
1404                continue;
1405        } else {
1406            pch->avail = 1;
1407        }
1408
1409        /* check the channel's mtu and whether it is still attached. */
1410        spin_lock_bh(&pch->downl);
1411        if (pch->chan == NULL) {
1412            /* can't use this channel, it's being deregistered */
1413            if (pch->speed == 0)
1414                nzero--;
1415            else
1416                totspeed -= pch->speed;
1417
1418            spin_unlock_bh(&pch->downl);
1419            pch->avail = 0;
1420            totlen = len;
1421            totfree--;
1422            nfree--;
1423            if (--navail == 0)
1424                break;
1425            continue;
1426        }
1427
1428        /*
1429        *if the channel speed is not set divide
1430        *the packet evenly among the free channels;
1431        *otherwise divide it according to the speed
1432        *of the channel we are going to transmit on
1433        */
1434        if (nfree > 0) {
1435            if (pch->speed == 0) {
1436                flen = totlen/nfree ;
1437                if (nbigger > 0) {
1438                    flen++;
1439                    nbigger--;
1440                }
1441            } else {
1442                flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) /
1443                    ((totspeed*totfree)/pch->speed)) - hdrlen;
1444                if (nbigger > 0) {
1445                    flen += ((totfree - nzero)*pch->speed)/totspeed;
1446                    nbigger -= ((totfree - nzero)*pch->speed)/
1447                            totspeed;
1448                }
1449            }
1450            nfree--;
1451        }
1452
1453        /*
1454         *check if we are on the last channel or
1455         *we exceded the lenght of the data to
1456         *fragment
1457         */
1458        if ((nfree <= 0) || (flen > len))
1459            flen = len;
1460        /*
1461         *it is not worth to tx on slow channels:
1462         *in that case from the resulting flen according to the
1463         *above formula will be equal or less than zero.
1464         *Skip the channel in this case
1465         */
1466        if (flen <= 0) {
1467            pch->avail = 2;
1468            spin_unlock_bh(&pch->downl);
1469            continue;
1470        }
1471
1472        mtu = pch->chan->mtu - hdrlen;
1473        if (mtu < 4)
1474            mtu = 4;
1475        if (flen > mtu)
1476            flen = mtu;
1477        if (flen == len)
1478            bits |= E;
1479        frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
1480        if (!frag)
1481            goto noskb;
1482        q = skb_put(frag, flen + hdrlen);
1483
1484        /* make the MP header */
1485        q[0] = PPP_MP >> 8;
1486        q[1] = PPP_MP;
1487        if (ppp->flags & SC_MP_XSHORTSEQ) {
1488            q[2] = bits + ((ppp->nxseq >> 8) & 0xf);
1489            q[3] = ppp->nxseq;
1490        } else {
1491            q[2] = bits;
1492            q[3] = ppp->nxseq >> 16;
1493            q[4] = ppp->nxseq >> 8;
1494            q[5] = ppp->nxseq;
1495        }
1496
1497        memcpy(q + hdrlen, p, flen);
1498
1499        /* try to send it down the channel */
1500        chan = pch->chan;
1501        if (!skb_queue_empty(&pch->file.xq) ||
1502            !chan->ops->start_xmit(chan, frag))
1503            skb_queue_tail(&pch->file.xq, frag);
1504        pch->had_frag = 1;
1505        p += flen;
1506        len -= flen;
1507        ++ppp->nxseq;
1508        bits = 0;
1509        spin_unlock_bh(&pch->downl);
1510    }
1511    ppp->nxchan = i;
1512
1513    return 1;
1514
1515 noskb:
1516    spin_unlock_bh(&pch->downl);
1517    if (ppp->debug & 1)
1518        printk(KERN_ERR "PPP: no memory (fragment)\n");
1519    ++ppp->dev->stats.tx_errors;
1520    ++ppp->nxseq;
1521    return 1; /* abandon the frame */
1522}
1523#endif /* CONFIG_PPP_MULTILINK */
1524
1525/*
1526 * Try to send data out on a channel.
1527 */
1528static void
1529ppp_channel_push(struct channel *pch)
1530{
1531    struct sk_buff *skb;
1532    struct ppp *ppp;
1533
1534    spin_lock_bh(&pch->downl);
1535    if (pch->chan) {
1536        while (!skb_queue_empty(&pch->file.xq)) {
1537            skb = skb_dequeue(&pch->file.xq);
1538            if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
1539                /* put the packet back and try again later */
1540                skb_queue_head(&pch->file.xq, skb);
1541                break;
1542            }
1543        }
1544    } else {
1545        /* channel got deregistered */
1546        skb_queue_purge(&pch->file.xq);
1547    }
1548    spin_unlock_bh(&pch->downl);
1549    /* see if there is anything from the attached unit to be sent */
1550    if (skb_queue_empty(&pch->file.xq)) {
1551        read_lock_bh(&pch->upl);
1552        ppp = pch->ppp;
1553        if (ppp)
1554            ppp_xmit_process(ppp);
1555        read_unlock_bh(&pch->upl);
1556    }
1557}
1558
1559/*
1560 * Receive-side routines.
1561 */
1562
1563/* misuse a few fields of the skb for MP reconstruction */
1564#define sequence priority
1565#define BEbits cb[0]
1566
1567static inline void
1568ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1569{
1570    ppp_recv_lock(ppp);
1571    if (!ppp->closing)
1572        ppp_receive_frame(ppp, skb, pch);
1573    else
1574        kfree_skb(skb);
1575    ppp_recv_unlock(ppp);
1576}
1577
1578void
1579ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
1580{
1581    struct channel *pch = chan->ppp;
1582    int proto;
1583
1584    if (!pch || skb->len == 0) {
1585        kfree_skb(skb);
1586        return;
1587    }
1588
1589    proto = PPP_PROTO(skb);
1590    read_lock_bh(&pch->upl);
1591    if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
1592        /* put it on the channel queue */
1593        skb_queue_tail(&pch->file.rq, skb);
1594        /* drop old frames if queue too long */
1595        while (pch->file.rq.qlen > PPP_MAX_RQLEN
1596               && (skb = skb_dequeue(&pch->file.rq)))
1597            kfree_skb(skb);
1598        wake_up_interruptible(&pch->file.rwait);
1599    } else {
1600        ppp_do_recv(pch->ppp, skb, pch);
1601    }
1602    read_unlock_bh(&pch->upl);
1603}
1604
1605/* Put a 0-length skb in the receive queue as an error indication */
1606void
1607ppp_input_error(struct ppp_channel *chan, int code)
1608{
1609    struct channel *pch = chan->ppp;
1610    struct sk_buff *skb;
1611
1612    if (!pch)
1613        return;
1614
1615    read_lock_bh(&pch->upl);
1616    if (pch->ppp) {
1617        skb = alloc_skb(0, GFP_ATOMIC);
1618        if (skb) {
1619            skb->len = 0; /* probably unnecessary */
1620            skb->cb[0] = code;
1621            ppp_do_recv(pch->ppp, skb, pch);
1622        }
1623    }
1624    read_unlock_bh(&pch->upl);
1625}
1626
1627/*
1628 * We come in here to process a received frame.
1629 * The receive side of the ppp unit is locked.
1630 */
1631static void
1632ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1633{
1634    if (pskb_may_pull(skb, 2)) {
1635#ifdef CONFIG_PPP_MULTILINK
1636        /* XXX do channel-level decompression here */
1637        if (PPP_PROTO(skb) == PPP_MP)
1638            ppp_receive_mp_frame(ppp, skb, pch);
1639        else
1640#endif /* CONFIG_PPP_MULTILINK */
1641            ppp_receive_nonmp_frame(ppp, skb);
1642        return;
1643    }
1644
1645    if (skb->len > 0)
1646        /* note: a 0-length skb is used as an error indication */
1647        ++ppp->dev->stats.rx_length_errors;
1648
1649    kfree_skb(skb);
1650    ppp_receive_error(ppp);
1651}
1652
1653static void
1654ppp_receive_error(struct ppp *ppp)
1655{
1656    ++ppp->dev->stats.rx_errors;
1657    if (ppp->vj)
1658        slhc_toss(ppp->vj);
1659}
1660
1661static void
1662ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
1663{
1664    struct sk_buff *ns;
1665    int proto, len, npi;
1666
1667    /*
1668     * Decompress the frame, if compressed.
1669     * Note that some decompressors need to see uncompressed frames
1670     * that come in as well as compressed frames.
1671     */
1672    if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)
1673        && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0)
1674        skb = ppp_decompress_frame(ppp, skb);
1675
1676    if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR)
1677        goto err;
1678
1679    proto = PPP_PROTO(skb);
1680    switch (proto) {
1681    case PPP_VJC_COMP:
1682        /* decompress VJ compressed packets */
1683        if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1684            goto err;
1685
1686        if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
1687            /* copy to a new sk_buff with more tailroom */
1688            ns = dev_alloc_skb(skb->len + 128);
1689            if (!ns) {
1690                printk(KERN_ERR"PPP: no memory (VJ decomp)\n");
1691                goto err;
1692            }
1693            skb_reserve(ns, 2);
1694            skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
1695            kfree_skb(skb);
1696            skb = ns;
1697        }
1698        else
1699            skb->ip_summed = CHECKSUM_NONE;
1700
1701        len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2);
1702        if (len <= 0) {
1703            printk(KERN_DEBUG "PPP: VJ decompression error\n");
1704            goto err;
1705        }
1706        len += 2;
1707        if (len > skb->len)
1708            skb_put(skb, len - skb->len);
1709        else if (len < skb->len)
1710            skb_trim(skb, len);
1711        proto = PPP_IP;
1712        break;
1713
1714    case PPP_VJC_UNCOMP:
1715        if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
1716            goto err;
1717
1718        /* Until we fix the decompressor need to make sure
1719         * data portion is linear.
1720         */
1721        if (!pskb_may_pull(skb, skb->len))
1722            goto err;
1723
1724        if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) {
1725            printk(KERN_ERR "PPP: VJ uncompressed error\n");
1726            goto err;
1727        }
1728        proto = PPP_IP;
1729        break;
1730
1731    case PPP_CCP:
1732        ppp_ccp_peek(ppp, skb, 1);
1733        break;
1734    }
1735
1736    ++ppp->dev->stats.rx_packets;
1737    ppp->dev->stats.rx_bytes += skb->len - 2;
1738
1739    npi = proto_to_npindex(proto);
1740    if (npi < 0) {
1741        /* control or unknown frame - pass it to pppd */
1742        skb_queue_tail(&ppp->file.rq, skb);
1743        /* limit queue length by dropping old frames */
1744        while (ppp->file.rq.qlen > PPP_MAX_RQLEN
1745               && (skb = skb_dequeue(&ppp->file.rq)))
1746            kfree_skb(skb);
1747        /* wake up any process polling or blocking on read */
1748        wake_up_interruptible(&ppp->file.rwait);
1749
1750    } else {
1751        /* network protocol frame - give it to the kernel */
1752
1753#ifdef CONFIG_PPP_FILTER
1754        /* check if the packet passes the pass and active filters */
1755        /* the filter instructions are constructed assuming
1756           a four-byte PPP header on each packet */
1757        if (ppp->pass_filter || ppp->active_filter) {
1758            if (skb_cloned(skb) &&
1759                pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
1760                goto err;
1761
1762            *skb_push(skb, 2) = 0;
1763            if (ppp->pass_filter
1764                && sk_run_filter(skb, ppp->pass_filter,
1765                         ppp->pass_len) == 0) {
1766                if (ppp->debug & 1)
1767                    printk(KERN_DEBUG "PPP: inbound frame "
1768                           "not passed\n");
1769                kfree_skb(skb);
1770                return;
1771            }
1772            if (!(ppp->active_filter
1773                  && sk_run_filter(skb, ppp->active_filter,
1774                           ppp->active_len) == 0))
1775                ppp->last_recv = jiffies;
1776            __skb_pull(skb, 2);
1777        } else
1778#endif /* CONFIG_PPP_FILTER */
1779            ppp->last_recv = jiffies;
1780
1781        if ((ppp->dev->flags & IFF_UP) == 0
1782            || ppp->npmode[npi] != NPMODE_PASS) {
1783            kfree_skb(skb);
1784        } else {
1785            /* chop off protocol */
1786            skb_pull_rcsum(skb, 2);
1787            skb->dev = ppp->dev;
1788            skb->protocol = htons(npindex_to_ethertype[npi]);
1789            skb_reset_mac_header(skb);
1790            netif_rx(skb);
1791        }
1792    }
1793    return;
1794
1795 err:
1796    kfree_skb(skb);
1797    ppp_receive_error(ppp);
1798}
1799
1800static struct sk_buff *
1801ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
1802{
1803    int proto = PPP_PROTO(skb);
1804    struct sk_buff *ns;
1805    int len;
1806
1807    /* Until we fix all the decompressor's need to make sure
1808     * data portion is linear.
1809     */
1810    if (!pskb_may_pull(skb, skb->len))
1811        goto err;
1812
1813    if (proto == PPP_COMP) {
1814        int obuff_size;
1815
1816        switch(ppp->rcomp->compress_proto) {
1817        case CI_MPPE:
1818            obuff_size = ppp->mru + PPP_HDRLEN + 1;
1819            break;
1820        default:
1821            obuff_size = ppp->mru + PPP_HDRLEN;
1822            break;
1823        }
1824
1825        ns = dev_alloc_skb(obuff_size);
1826        if (!ns) {
1827            printk(KERN_ERR "ppp_decompress_frame: no memory\n");
1828            goto err;
1829        }
1830        /* the decompressor still expects the A/C bytes in the hdr */
1831        len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
1832                skb->len + 2, ns->data, obuff_size);
1833        if (len < 0) {
1834            /* Pass the compressed frame to pppd as an
1835               error indication. */
1836            if (len == DECOMP_FATALERROR)
1837                ppp->rstate |= SC_DC_FERROR;
1838            kfree_skb(ns);
1839            goto err;
1840        }
1841
1842        kfree_skb(skb);
1843        skb = ns;
1844        skb_put(skb, len);
1845        skb_pull(skb, 2); /* pull off the A/C bytes */
1846
1847    } else {
1848        /* Uncompressed frame - pass to decompressor so it
1849           can update its dictionary if necessary. */
1850        if (ppp->rcomp->incomp)
1851            ppp->rcomp->incomp(ppp->rc_state, skb->data - 2,
1852                       skb->len + 2);
1853    }
1854
1855    return skb;
1856
1857 err:
1858    ppp->rstate |= SC_DC_ERROR;
1859    ppp_receive_error(ppp);
1860    return skb;
1861}
1862
1863#ifdef CONFIG_PPP_MULTILINK
1864/*
1865 * Receive a multilink frame.
1866 * We put it on the reconstruction queue and then pull off
1867 * as many completed frames as we can.
1868 */
1869static void
1870ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
1871{
1872    u32 mask, seq;
1873    struct channel *ch;
1874    int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
1875
1876    if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
1877        goto err; /* no good, throw it away */
1878
1879    /* Decode sequence number and begin/end bits */
1880    if (ppp->flags & SC_MP_SHORTSEQ) {
1881        seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3];
1882        mask = 0xfff;
1883    } else {
1884        seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5];
1885        mask = 0xffffff;
1886    }
1887    skb->BEbits = skb->data[2];
1888    skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */
1889
1890    /*
1891     * Do protocol ID decompression on the first fragment of each packet.
1892     */
1893    if ((skb->BEbits & B) && (skb->data[0] & 1))
1894        *skb_push(skb, 1) = 0;
1895
1896    /*
1897     * Expand sequence number to 32 bits, making it as close
1898     * as possible to ppp->minseq.
1899     */
1900    seq |= ppp->minseq & ~mask;
1901    if ((int)(ppp->minseq - seq) > (int)(mask >> 1))
1902        seq += mask + 1;
1903    else if ((int)(seq - ppp->minseq) > (int)(mask >> 1))
1904        seq -= mask + 1; /* should never happen */
1905    skb->sequence = seq;
1906    pch->lastseq = seq;
1907
1908    /*
1909     * If this packet comes before the next one we were expecting,
1910     * drop it.
1911     */
1912    if (seq_before(seq, ppp->nextseq)) {
1913        kfree_skb(skb);
1914        ++ppp->dev->stats.rx_dropped;
1915        ppp_receive_error(ppp);
1916        return;
1917    }
1918
1919    /*
1920     * Reevaluate minseq, the minimum over all channels of the
1921     * last sequence number received on each channel. Because of
1922     * the increasing sequence number rule, we know that any fragment
1923     * before `minseq' which hasn't arrived is never going to arrive.
1924     * The list of channels can't change because we have the receive
1925     * side of the ppp unit locked.
1926     */
1927    list_for_each_entry(ch, &ppp->channels, clist) {
1928        if (seq_before(ch->lastseq, seq))
1929            seq = ch->lastseq;
1930    }
1931    if (seq_before(ppp->minseq, seq))
1932        ppp->minseq = seq;
1933
1934    /* Put the fragment on the reconstruction queue */
1935    ppp_mp_insert(ppp, skb);
1936
1937    /* If the queue is getting long, don't wait any longer for packets
1938       before the start of the queue. */
1939    if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) {
1940        struct sk_buff *skb = skb_peek(&ppp->mrq);
1941        if (seq_before(ppp->minseq, skb->sequence))
1942            ppp->minseq = skb->sequence;
1943    }
1944
1945    /* Pull completed packets off the queue and receive them. */
1946    while ((skb = ppp_mp_reconstruct(ppp)))
1947        ppp_receive_nonmp_frame(ppp, skb);
1948
1949    return;
1950
1951 err:
1952    kfree_skb(skb);
1953    ppp_receive_error(ppp);
1954}
1955
1956/*
1957 * Insert a fragment on the MP reconstruction queue.
1958 * The queue is ordered by increasing sequence number.
1959 */
1960static void
1961ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb)
1962{
1963    struct sk_buff *p;
1964    struct sk_buff_head *list = &ppp->mrq;
1965    u32 seq = skb->sequence;
1966
1967    /* N.B. we don't need to lock the list lock because we have the
1968       ppp unit receive-side lock. */
1969    skb_queue_walk(list, p) {
1970        if (seq_before(seq, p->sequence))
1971            break;
1972    }
1973    __skb_queue_before(list, p, skb);
1974}
1975
1976/*
1977 * Reconstruct a packet from the MP fragment queue.
1978 * We go through increasing sequence numbers until we find a
1979 * complete packet, or we get to the sequence number for a fragment
1980 * which hasn't arrived but might still do so.
1981 */
1982static struct sk_buff *
1983ppp_mp_reconstruct(struct ppp *ppp)
1984{
1985    u32 seq = ppp->nextseq;
1986    u32 minseq = ppp->minseq;
1987    struct sk_buff_head *list = &ppp->mrq;
1988    struct sk_buff *p, *next;
1989    struct sk_buff *head, *tail;
1990    struct sk_buff *skb = NULL;
1991    int lost = 0, len = 0;
1992
1993    if (ppp->mrru == 0) /* do nothing until mrru is set */
1994        return NULL;
1995    head = list->next;
1996    tail = NULL;
1997    for (p = head; p != (struct sk_buff *) list; p = next) {
1998        next = p->next;
1999        if (seq_before(p->sequence, seq)) {
2000            /* this can't happen, anyway ignore the skb */
2001            printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n",
2002                   p->sequence, seq);
2003            head = next;
2004            continue;
2005        }
2006        if (p->sequence != seq) {
2007            /* Fragment `seq' is missing. If it is after
2008               minseq, it might arrive later, so stop here. */
2009            if (seq_after(seq, minseq))
2010                break;
2011            /* Fragment `seq' is lost, keep going. */
2012            lost = 1;
2013            seq = seq_before(minseq, p->sequence)?
2014                minseq + 1: p->sequence;
2015            next = p;
2016            continue;
2017        }
2018
2019        /*
2020         * At this point we know that all the fragments from
2021         * ppp->nextseq to seq are either present or lost.
2022         * Also, there are no complete packets in the queue
2023         * that have no missing fragments and end before this
2024         * fragment.
2025         */
2026
2027        /* B bit set indicates this fragment starts a packet */
2028        if (p->BEbits & B) {
2029            head = p;
2030            lost = 0;
2031            len = 0;
2032        }
2033
2034        len += p->len;
2035
2036        /* Got a complete packet yet? */
2037        if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) {
2038            if (len > ppp->mrru + 2) {
2039                ++ppp->dev->stats.rx_length_errors;
2040                printk(KERN_DEBUG "PPP: reconstructed packet"
2041                       " is too long (%d)\n", len);
2042            } else if (p == head) {
2043                /* fragment is complete packet - reuse skb */
2044                tail = p;
2045                skb = skb_get(p);
2046                break;
2047            } else if ((skb = dev_alloc_skb(len)) == NULL) {
2048                ++ppp->dev->stats.rx_missed_errors;
2049                printk(KERN_DEBUG "PPP: no memory for "
2050                       "reconstructed packet");
2051            } else {
2052                tail = p;
2053                break;
2054            }
2055            ppp->nextseq = seq + 1;
2056        }
2057
2058        /*
2059         * If this is the ending fragment of a packet,
2060         * and we haven't found a complete valid packet yet,
2061         * we can discard up to and including this fragment.
2062         */
2063        if (p->BEbits & E)
2064            head = next;
2065
2066        ++seq;
2067    }
2068
2069    /* If we have a complete packet, copy it all into one skb. */
2070    if (tail != NULL) {
2071        /* If we have discarded any fragments,
2072           signal a receive error. */
2073        if (head->sequence != ppp->nextseq) {
2074            if (ppp->debug & 1)
2075                printk(KERN_DEBUG " missed pkts %u..%u\n",
2076                       ppp->nextseq, head->sequence-1);
2077            ++ppp->dev->stats.rx_dropped;
2078            ppp_receive_error(ppp);
2079        }
2080
2081        if (head != tail)
2082            /* copy to a single skb */
2083            for (p = head; p != tail->next; p = p->next)
2084                skb_copy_bits(p, 0, skb_put(skb, p->len), p->len);
2085        ppp->nextseq = tail->sequence + 1;
2086        head = tail->next;
2087    }
2088
2089    /* Discard all the skbuffs that we have copied the data out of
2090       or that we can't use. */
2091    while ((p = list->next) != head) {
2092        __skb_unlink(p, list);
2093        kfree_skb(p);
2094    }
2095
2096    return skb;
2097}
2098#endif /* CONFIG_PPP_MULTILINK */
2099
2100/*
2101 * Channel interface.
2102 */
2103
2104/* Create a new, unattached ppp channel. */
2105int ppp_register_channel(struct ppp_channel *chan)
2106{
2107    return ppp_register_net_channel(current->nsproxy->net_ns, chan);
2108}
2109
2110/* Create a new, unattached ppp channel for specified net. */
2111int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
2112{
2113    struct channel *pch;
2114    struct ppp_net *pn;
2115
2116    pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
2117    if (!pch)
2118        return -ENOMEM;
2119
2120    pn = ppp_pernet(net);
2121
2122    pch->ppp = NULL;
2123    pch->chan = chan;
2124    pch->chan_net = net;
2125    chan->ppp = pch;
2126    init_ppp_file(&pch->file, CHANNEL);
2127    pch->file.hdrlen = chan->hdrlen;
2128#ifdef CONFIG_PPP_MULTILINK
2129    pch->lastseq = -1;
2130#endif /* CONFIG_PPP_MULTILINK */
2131    init_rwsem(&pch->chan_sem);
2132    spin_lock_init(&pch->downl);
2133    rwlock_init(&pch->upl);
2134
2135    spin_lock_bh(&pn->all_channels_lock);
2136    pch->file.index = ++pn->last_channel_index;
2137    list_add(&pch->list, &pn->new_channels);
2138    atomic_inc(&channel_count);
2139    spin_unlock_bh(&pn->all_channels_lock);
2140
2141    return 0;
2142}
2143
2144/*
2145 * Return the index of a channel.
2146 */
2147int ppp_channel_index(struct ppp_channel *chan)
2148{
2149    struct channel *pch = chan->ppp;
2150
2151    if (pch)
2152        return pch->file.index;
2153    return -1;
2154}
2155
2156/*
2157 * Return the PPP unit number to which a channel is connected.
2158 */
2159int ppp_unit_number(struct ppp_channel *chan)
2160{
2161    struct channel *pch = chan->ppp;
2162    int unit = -1;
2163
2164    if (pch) {
2165        read_lock_bh(&pch->upl);
2166        if (pch->ppp)
2167            unit = pch->ppp->file.index;
2168        read_unlock_bh(&pch->upl);
2169    }
2170    return unit;
2171}
2172
2173/*
2174 * Disconnect a channel from the generic layer.
2175 * This must be called in process context.
2176 */
2177void
2178ppp_unregister_channel(struct ppp_channel *chan)
2179{
2180    struct channel *pch = chan->ppp;
2181    struct ppp_net *pn;
2182
2183    if (!pch)
2184        return; /* should never happen */
2185
2186    chan->ppp = NULL;
2187
2188    /*
2189     * This ensures that we have returned from any calls into the
2190     * the channel's start_xmit or ioctl routine before we proceed.
2191     */
2192    down_write(&pch->chan_sem);
2193    spin_lock_bh(&pch->downl);
2194    pch->chan = NULL;
2195    spin_unlock_bh(&pch->downl);
2196    up_write(&pch->chan_sem);
2197    ppp_disconnect_channel(pch);
2198
2199    pn = ppp_pernet(pch->chan_net);
2200    spin_lock_bh(&pn->all_channels_lock);
2201    list_del(&pch->list);
2202    spin_unlock_bh(&pn->all_channels_lock);
2203
2204    pch->file.dead = 1;
2205    wake_up_interruptible(&pch->file.rwait);
2206    if (atomic_dec_and_test(&pch->file.refcnt))
2207        ppp_destroy_channel(pch);
2208}
2209
2210/*
2211 * Callback from a channel when it can accept more to transmit.
2212 * This should be called at BH/softirq level, not interrupt level.
2213 */
2214void
2215ppp_output_wakeup(struct ppp_channel *chan)
2216{
2217    struct channel *pch = chan->ppp;
2218
2219    if (!pch)
2220        return;
2221    ppp_channel_push(pch);
2222}
2223
2224/*
2225 * Compression control.
2226 */
2227
2228/* Process the PPPIOCSCOMPRESS ioctl. */
2229static int
2230ppp_set_compress(struct ppp *ppp, unsigned long arg)
2231{
2232    int err;
2233    struct compressor *cp, *ocomp;
2234    struct ppp_option_data data;
2235    void *state, *ostate;
2236    unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
2237
2238    err = -EFAULT;
2239    if (copy_from_user(&data, (void __user *) arg, sizeof(data))
2240        || (data.length <= CCP_MAX_OPTION_LENGTH
2241        && copy_from_user(ccp_option, (void __user *) data.ptr, data.length)))
2242        goto out;
2243    err = -EINVAL;
2244    if (data.length > CCP_MAX_OPTION_LENGTH
2245        || ccp_option[1] < 2 || ccp_option[1] > data.length)
2246        goto out;
2247
2248    cp = try_then_request_module(
2249        find_compressor(ccp_option[0]),
2250        "ppp-compress-%d", ccp_option[0]);
2251    if (!cp)
2252        goto out;
2253
2254    err = -ENOBUFS;
2255    if (data.transmit) {
2256        state = cp->comp_alloc(ccp_option, data.length);
2257        if (state) {
2258            ppp_xmit_lock(ppp);
2259            ppp->xstate &= ~SC_COMP_RUN;
2260            ocomp = ppp->xcomp;
2261            ostate = ppp->xc_state;
2262            ppp->xcomp = cp;
2263            ppp->xc_state = state;
2264            ppp_xmit_unlock(ppp);
2265            if (ostate) {
2266                ocomp->comp_free(ostate);
2267                module_put(ocomp->owner);
2268            }
2269            err = 0;
2270        } else
2271            module_put(cp->owner);
2272
2273    } else {
2274        state = cp->decomp_alloc(ccp_option, data.length);
2275        if (state) {
2276            ppp_recv_lock(ppp);
2277            ppp->rstate &= ~SC_DECOMP_RUN;
2278            ocomp = ppp->rcomp;
2279            ostate = ppp->rc_state;
2280            ppp->rcomp = cp;
2281            ppp->rc_state = state;
2282            ppp_recv_unlock(ppp);
2283            if (ostate) {
2284                ocomp->decomp_free(ostate);
2285                module_put(ocomp->owner);
2286            }
2287            err = 0;
2288        } else
2289            module_put(cp->owner);
2290    }
2291
2292 out:
2293    return err;
2294}
2295
2296/*
2297 * Look at a CCP packet and update our state accordingly.
2298 * We assume the caller has the xmit or recv path locked.
2299 */
2300static void
2301ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound)
2302{
2303    unsigned char *dp;
2304    int len;
2305
2306    if (!pskb_may_pull(skb, CCP_HDRLEN + 2))
2307        return; /* no header */
2308    dp = skb->data + 2;
2309
2310    switch (CCP_CODE(dp)) {
2311    case CCP_CONFREQ:
2312
2313        /* A ConfReq starts negotiation of compression
2314         * in one direction of transmission,
2315         * and hence brings it down...but which way?
2316         *
2317         * Remember:
2318         * A ConfReq indicates what the sender would like to receive
2319         */
2320        if(inbound)
2321            /* He is proposing what I should send */
2322            ppp->xstate &= ~SC_COMP_RUN;
2323        else
2324            /* I am proposing to what he should send */
2325            ppp->rstate &= ~SC_DECOMP_RUN;
2326
2327        break;
2328
2329    case CCP_TERMREQ:
2330    case CCP_TERMACK:
2331        /*
2332         * CCP is going down, both directions of transmission
2333         */
2334        ppp->rstate &= ~SC_DECOMP_RUN;
2335        ppp->xstate &= ~SC_COMP_RUN;
2336        break;
2337
2338    case CCP_CONFACK:
2339        if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN)
2340            break;
2341        len = CCP_LENGTH(dp);
2342        if (!pskb_may_pull(skb, len + 2))
2343            return; /* too short */
2344        dp += CCP_HDRLEN;
2345        len -= CCP_HDRLEN;
2346        if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp))
2347            break;
2348        if (inbound) {
2349            /* we will start receiving compressed packets */
2350            if (!ppp->rc_state)
2351                break;
2352            if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len,
2353                    ppp->file.index, 0, ppp->mru, ppp->debug)) {
2354                ppp->rstate |= SC_DECOMP_RUN;
2355                ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR);
2356            }
2357        } else {
2358            /* we will soon start sending compressed packets */
2359            if (!ppp->xc_state)
2360                break;
2361            if (ppp->xcomp->comp_init(ppp->xc_state, dp, len,
2362                    ppp->file.index, 0, ppp->debug))
2363                ppp->xstate |= SC_COMP_RUN;
2364        }
2365        break;
2366
2367    case CCP_RESETACK:
2368        /* reset the [de]compressor */
2369        if ((ppp->flags & SC_CCP_UP) == 0)
2370            break;
2371        if (inbound) {
2372            if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) {
2373                ppp->rcomp->decomp_reset(ppp->rc_state);
2374                ppp->rstate &= ~SC_DC_ERROR;
2375            }
2376        } else {
2377            if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN))
2378                ppp->xcomp->comp_reset(ppp->xc_state);
2379        }
2380        break;
2381    }
2382}
2383
2384/* Free up compression resources. */
2385static void
2386ppp_ccp_closed(struct ppp *ppp)
2387{
2388    void *xstate, *rstate;
2389    struct compressor *xcomp, *rcomp;
2390
2391    ppp_lock(ppp);
2392    ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP);
2393    ppp->xstate = 0;
2394    xcomp = ppp->xcomp;
2395    xstate = ppp->xc_state;
2396    ppp->xc_state = NULL;
2397    ppp->rstate = 0;
2398    rcomp = ppp->rcomp;
2399    rstate = ppp->rc_state;
2400    ppp->rc_state = NULL;
2401    ppp_unlock(ppp);
2402
2403    if (xstate) {
2404        xcomp->comp_free(xstate);
2405        module_put(xcomp->owner);
2406    }
2407    if (rstate) {
2408        rcomp->decomp_free(rstate);
2409        module_put(rcomp->owner);
2410    }
2411}
2412
2413/* List of compressors. */
2414static LIST_HEAD(compressor_list);
2415static DEFINE_SPINLOCK(compressor_list_lock);
2416
2417struct compressor_entry {
2418    struct list_head list;
2419    struct compressor *comp;
2420};
2421
2422static struct compressor_entry *
2423find_comp_entry(int proto)
2424{
2425    struct compressor_entry *ce;
2426
2427    list_for_each_entry(ce, &compressor_list, list) {
2428        if (ce->comp->compress_proto == proto)
2429            return ce;
2430    }
2431    return NULL;
2432}
2433
2434/* Register a compressor */
2435int
2436ppp_register_compressor(struct compressor *cp)
2437{
2438    struct compressor_entry *ce;
2439    int ret;
2440    spin_lock(&compressor_list_lock);
2441    ret = -EEXIST;
2442    if (find_comp_entry(cp->compress_proto))
2443        goto out;
2444    ret = -ENOMEM;
2445    ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC);
2446    if (!ce)
2447        goto out;
2448    ret = 0;
2449    ce->comp = cp;
2450    list_add(&ce->list, &compressor_list);
2451 out:
2452    spin_unlock(&compressor_list_lock);
2453    return ret;
2454}
2455
2456/* Unregister a compressor */
2457void
2458ppp_unregister_compressor(struct compressor *cp)
2459{
2460    struct compressor_entry *ce;
2461
2462    spin_lock(&compressor_list_lock);
2463    ce = find_comp_entry(cp->compress_proto);
2464    if (ce && ce->comp == cp) {
2465        list_del(&ce->list);
2466        kfree(ce);
2467    }
2468    spin_unlock(&compressor_list_lock);
2469}
2470
2471/* Find a compressor. */
2472static struct compressor *
2473find_compressor(int type)
2474{
2475    struct compressor_entry *ce;
2476    struct compressor *cp = NULL;
2477
2478    spin_lock(&compressor_list_lock);
2479    ce = find_comp_entry(type);
2480    if (ce) {
2481        cp = ce->comp;
2482        if (!try_module_get(cp->owner))
2483            cp = NULL;
2484    }
2485    spin_unlock(&compressor_list_lock);
2486    return cp;
2487}
2488
2489/*
2490 * Miscelleneous stuff.
2491 */
2492
2493static void
2494ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
2495{
2496    struct slcompress *vj = ppp->vj;
2497
2498    memset(st, 0, sizeof(*st));
2499    st->p.ppp_ipackets = ppp->dev->stats.rx_packets;
2500    st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
2501    st->p.ppp_ibytes = ppp->dev->stats.rx_bytes;
2502    st->p.ppp_opackets = ppp->dev->stats.tx_packets;
2503    st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
2504    st->p.ppp_obytes = ppp->dev->stats.tx_bytes;
2505    if (!vj)
2506        return;
2507    st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
2508    st->vj.vjs_compressed = vj->sls_o_compressed;
2509    st->vj.vjs_searches = vj->sls_o_searches;
2510    st->vj.vjs_misses = vj->sls_o_misses;
2511    st->vj.vjs_errorin = vj->sls_i_error;
2512    st->vj.vjs_tossed = vj->sls_i_tossed;
2513    st->vj.vjs_uncompressedin = vj->sls_i_uncompressed;
2514    st->vj.vjs_compressedin = vj->sls_i_compressed;
2515}
2516
2517/*
2518 * Stuff for handling the lists of ppp units and channels
2519 * and for initialization.
2520 */
2521
2522/*
2523 * Create a new ppp interface unit. Fails if it can't allocate memory
2524 * or if there is already a unit with the requested number.
2525 * unit == -1 means allocate a new number.
2526 */
2527static struct ppp *
2528ppp_create_interface(struct net *net, int unit, int *retp)
2529{
2530    struct ppp *ppp;
2531    struct ppp_net *pn;
2532    struct net_device *dev = NULL;
2533    int ret = -ENOMEM;
2534    int i;
2535
2536    dev = alloc_netdev(sizeof(struct ppp), "", ppp_setup);
2537    if (!dev)
2538        goto out1;
2539
2540    pn = ppp_pernet(net);
2541
2542    ppp = netdev_priv(dev);
2543    ppp->dev = dev;
2544    ppp->mru = PPP_MRU;
2545    init_ppp_file(&ppp->file, INTERFACE);
2546    ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */
2547    for (i = 0; i < NUM_NP; ++i)
2548        ppp->npmode[i] = NPMODE_PASS;
2549    INIT_LIST_HEAD(&ppp->channels);
2550    spin_lock_init(&ppp->rlock);
2551    spin_lock_init(&ppp->wlock);
2552#ifdef CONFIG_PPP_MULTILINK
2553    ppp->minseq = -1;
2554    skb_queue_head_init(&ppp->mrq);
2555#endif /* CONFIG_PPP_MULTILINK */
2556
2557    /*
2558     * drum roll: don't forget to set
2559     * the net device is belong to
2560     */
2561    dev_net_set(dev, net);
2562
2563    ret = -EEXIST;
2564    mutex_lock(&pn->all_ppp_mutex);
2565
2566    if (unit < 0) {
2567        unit = unit_get(&pn->units_idr, ppp);
2568        if (unit < 0) {
2569            *retp = unit;
2570            goto out2;
2571        }
2572    } else {
2573        if (unit_find(&pn->units_idr, unit))
2574            goto out2; /* unit already exists */
2575        /*
2576         * if caller need a specified unit number
2577         * lets try to satisfy him, otherwise --
2578         * he should better ask us for new unit number
2579         *
2580         * NOTE: yes I know that returning EEXIST it's not
2581         * fair but at least pppd will ask us to allocate
2582         * new unit in this case so user is happy :)
2583         */
2584        unit = unit_set(&pn->units_idr, ppp, unit);
2585        if (unit < 0)
2586            goto out2;
2587    }
2588
2589    /* Initialize the new ppp unit */
2590    ppp->file.index = unit;
2591    sprintf(dev->name, "ppp%d", unit);
2592
2593    ret = register_netdev(dev);
2594    if (ret != 0) {
2595        unit_put(&pn->units_idr, unit);
2596        printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
2597               dev->name, ret);
2598        goto out2;
2599    }
2600
2601    ppp->ppp_net = net;
2602
2603    atomic_inc(&ppp_unit_count);
2604    mutex_unlock(&pn->all_ppp_mutex);
2605
2606    *retp = 0;
2607    return ppp;
2608
2609out2:
2610    mutex_unlock(&pn->all_ppp_mutex);
2611    free_netdev(dev);
2612out1:
2613    *retp = ret;
2614    return NULL;
2615}
2616
2617/*
2618 * Initialize a ppp_file structure.
2619 */
2620static void
2621init_ppp_file(struct ppp_file *pf, int kind)
2622{
2623    pf->kind = kind;
2624    skb_queue_head_init(&pf->xq);
2625    skb_queue_head_init(&pf->rq);
2626    atomic_set(&pf->refcnt, 1);
2627    init_waitqueue_head(&pf->rwait);
2628}
2629
2630/*
2631 * Take down a ppp interface unit - called when the owning file
2632 * (the one that created the unit) is closed or detached.
2633 */
2634static void ppp_shutdown_interface(struct ppp *ppp)
2635{
2636    struct ppp_net *pn;
2637
2638    pn = ppp_pernet(ppp->ppp_net);
2639    mutex_lock(&pn->all_ppp_mutex);
2640
2641    /* This will call dev_close() for us. */
2642    ppp_lock(ppp);
2643    if (!ppp->closing) {
2644        ppp->closing = 1;
2645        ppp_unlock(ppp);
2646        unregister_netdev(ppp->dev);
2647    } else
2648        ppp_unlock(ppp);
2649
2650    unit_put(&pn->units_idr, ppp->file.index);
2651    ppp->file.dead = 1;
2652    ppp->owner = NULL;
2653    wake_up_interruptible(&ppp->file.rwait);
2654
2655    mutex_unlock(&pn->all_ppp_mutex);
2656}
2657
2658/*
2659 * Free the memory used by a ppp unit. This is only called once
2660 * there are no channels connected to the unit and no file structs
2661 * that reference the unit.
2662 */
2663static void ppp_destroy_interface(struct ppp *ppp)
2664{
2665    atomic_dec(&ppp_unit_count);
2666
2667    if (!ppp->file.dead || ppp->n_channels) {
2668        /* "can't happen" */
2669        printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d "
2670               "n_channels=%d !\n", ppp, ppp->file.dead,
2671               ppp->n_channels);
2672        return;
2673    }
2674
2675    ppp_ccp_closed(ppp);
2676    if (ppp->vj) {
2677        slhc_free(ppp->vj);
2678        ppp->vj = NULL;
2679    }
2680    skb_queue_purge(&ppp->file.xq);
2681    skb_queue_purge(&ppp->file.rq);
2682#ifdef CONFIG_PPP_MULTILINK
2683    skb_queue_purge(&ppp->mrq);
2684#endif /* CONFIG_PPP_MULTILINK */
2685#ifdef CONFIG_PPP_FILTER
2686    kfree(ppp->pass_filter);
2687    ppp->pass_filter = NULL;
2688    kfree(ppp->active_filter);
2689    ppp->active_filter = NULL;
2690#endif /* CONFIG_PPP_FILTER */
2691
2692    kfree_skb(ppp->xmit_pending);
2693
2694    free_netdev(ppp->dev);
2695}
2696
2697/*
2698 * Locate an existing ppp unit.
2699 * The caller should have locked the all_ppp_mutex.
2700 */
2701static struct ppp *
2702ppp_find_unit(struct ppp_net *pn, int unit)
2703{
2704    return unit_find(&pn->units_idr, unit);
2705}
2706
2707/*
2708 * Locate an existing ppp channel.
2709 * The caller should have locked the all_channels_lock.
2710 * First we look in the new_channels list, then in the
2711 * all_channels list. If found in the new_channels list,
2712 * we move it to the all_channels list. This is for speed
2713 * when we have a lot of channels in use.
2714 */
2715static struct channel *
2716ppp_find_channel(struct ppp_net *pn, int unit)
2717{
2718    struct channel *pch;
2719
2720    list_for_each_entry(pch, &pn->new_channels, list) {
2721        if (pch->file.index == unit) {
2722            list_move(&pch->list, &pn->all_channels);
2723            return pch;
2724        }
2725    }
2726
2727    list_for_each_entry(pch, &pn->all_channels, list) {
2728        if (pch->file.index == unit)
2729            return pch;
2730    }
2731
2732    return NULL;
2733}
2734
2735/*
2736 * Connect a PPP channel to a PPP interface unit.
2737 */
2738static int
2739ppp_connect_channel(struct channel *pch, int unit)
2740{
2741    struct ppp *ppp;
2742    struct ppp_net *pn;
2743    int ret = -ENXIO;
2744    int hdrlen;
2745
2746    pn = ppp_pernet(pch->chan_net);
2747
2748    mutex_lock(&pn->all_ppp_mutex);
2749    ppp = ppp_find_unit(pn, unit);
2750    if (!ppp)
2751        goto out;
2752    write_lock_bh(&pch->upl);
2753    ret = -EINVAL;
2754    if (pch->ppp)
2755        goto outl;
2756
2757    ppp_lock(ppp);
2758    if (pch->file.hdrlen > ppp->file.hdrlen)
2759        ppp->file.hdrlen = pch->file.hdrlen;
2760    hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */
2761    if (hdrlen > ppp->dev->hard_header_len)
2762        ppp->dev->hard_header_len = hdrlen;
2763    list_add_tail(&pch->clist, &ppp->channels);
2764    ++ppp->n_channels;
2765    pch->ppp = ppp;
2766    atomic_inc(&ppp->file.refcnt);
2767    ppp_unlock(ppp);
2768    ret = 0;
2769
2770 outl:
2771    write_unlock_bh(&pch->upl);
2772 out:
2773    mutex_unlock(&pn->all_ppp_mutex);
2774    return ret;
2775}
2776
2777/*
2778 * Disconnect a channel from its ppp unit.
2779 */
2780static int
2781ppp_disconnect_channel(struct channel *pch)
2782{
2783    struct ppp *ppp;
2784    int err = -EINVAL;
2785
2786    write_lock_bh(&pch->upl);
2787    ppp = pch->ppp;
2788    pch->ppp = NULL;
2789    write_unlock_bh(&pch->upl);
2790    if (ppp) {
2791        /* remove it from the ppp unit's list */
2792        ppp_lock(ppp);
2793        list_del(&pch->clist);
2794        if (--ppp->n_channels == 0)
2795            wake_up_interruptible(&ppp->file.rwait);
2796        ppp_unlock(ppp);
2797        if (atomic_dec_and_test(&ppp->file.refcnt))
2798            ppp_destroy_interface(ppp);
2799        err = 0;
2800    }
2801    return err;
2802}
2803
2804/*
2805 * Free up the resources used by a ppp channel.
2806 */
2807static void ppp_destroy_channel(struct channel *pch)
2808{
2809    atomic_dec(&channel_count);
2810
2811    if (!pch->file.dead) {
2812        /* "can't happen" */
2813        printk(KERN_ERR "ppp: destroying undead channel %p !\n",
2814               pch);
2815        return;
2816    }
2817    skb_queue_purge(&pch->file.xq);
2818    skb_queue_purge(&pch->file.rq);
2819    kfree(pch);
2820}
2821
2822static void __exit ppp_cleanup(void)
2823{
2824    /* should never happen */
2825    if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
2826        printk(KERN_ERR "PPP: removing module but units remain!\n");
2827    unregister_chrdev(PPP_MAJOR, "ppp");
2828    device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
2829    class_destroy(ppp_class);
2830    unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
2831}
2832
2833/*
2834 * Units handling. Caller must protect concurrent access
2835 * by holding all_ppp_mutex
2836 */
2837
2838/* associate pointer with specified number */
2839static int unit_set(struct idr *p, void *ptr, int n)
2840{
2841    int unit, err;
2842
2843again:
2844    if (!idr_pre_get(p, GFP_KERNEL)) {
2845        printk(KERN_ERR "PPP: No free memory for idr\n");
2846        return -ENOMEM;
2847    }
2848
2849    err = idr_get_new_above(p, ptr, n, &unit);
2850    if (err == -EAGAIN)
2851        goto again;
2852
2853    if (unit != n) {
2854        idr_remove(p, unit);
2855        return -EINVAL;
2856    }
2857
2858    return unit;
2859}
2860
2861/* get new free unit number and associate pointer with it */
2862static int unit_get(struct idr *p, void *ptr)
2863{
2864    int unit, err;
2865
2866again:
2867    if (!idr_pre_get(p, GFP_KERNEL)) {
2868        printk(KERN_ERR "PPP: No free memory for idr\n");
2869        return -ENOMEM;
2870    }
2871
2872    err = idr_get_new_above(p, ptr, 0, &unit);
2873    if (err == -EAGAIN)
2874        goto again;
2875
2876    return unit;
2877}
2878
2879/* put unit number back to a pool */
2880static void unit_put(struct idr *p, int n)
2881{
2882    idr_remove(p, n);
2883}
2884
2885/* get pointer associated with the number */
2886static void *unit_find(struct idr *p, int n)
2887{
2888    return idr_find(p, n);
2889}
2890
2891/* Module/initialization stuff */
2892
2893module_init(ppp_init);
2894module_exit(ppp_cleanup);
2895
2896EXPORT_SYMBOL(ppp_register_net_channel);
2897EXPORT_SYMBOL(ppp_register_channel);
2898EXPORT_SYMBOL(ppp_unregister_channel);
2899EXPORT_SYMBOL(ppp_channel_index);
2900EXPORT_SYMBOL(ppp_unit_number);
2901EXPORT_SYMBOL(ppp_input);
2902EXPORT_SYMBOL(ppp_input_error);
2903EXPORT_SYMBOL(ppp_output_wakeup);
2904EXPORT_SYMBOL(ppp_register_compressor);
2905EXPORT_SYMBOL(ppp_unregister_compressor);
2906MODULE_LICENSE("GPL");
2907MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR);
2908MODULE_ALIAS("/dev/ppp");
2909

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