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ppp_generic.c
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linux-6.19.14/drivers/net/ppp/ppp_generic.c
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, 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(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(ppp->dev); 416 rtnl_unlock(); 417 } 418 if (refcount_dec_and_test(&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(&pf->rwait, &wait); 447 for (;;) { 448 set_current_state(TASK_INTERRUPTIBLE); 449 skb = skb_dequeue(&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(&pf->rwait, &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(&to, ITER_DEST, &iov, 1, count); 492 if (skb_copy_datagram_iter(skb, 0, &to, 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(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(count + pf->hdrlen, GFP_KERNEL); 525 if (!skb) 526 goto out; 527 skb_reserve(skb, pf->hdrlen); 528 ret = -EFAULT; 529 if (copy_from_user(skb_put(skb, count), buf, 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(&pf->xq, 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(file, &pf->rwait, wait); 564 mask = EPOLLOUT | EPOLLWRNORM; 565 if (skb_peek(&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(uprog->filter, 596 uprog->len, sizeof(struct sock_filter)); 597 if (IS_ERR(fprog.filter)) 598 return ERR_CAST(fprog.filter); 599 600 err = bpf_prog_create(&res, &fprog); 601 kfree(fprog.filter); 602 603 return err ? ERR_PTR(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(&uprog, p, sizeof(struct sock_fprog))) 611 return ERR_PTR(-EFAULT); 612 return get_filter(&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(&uprog32, p, sizeof(struct sock_fprog32))) 630 return ERR_PTR(-EFAULT); 631 uprog.len = uprog32.len; 632 uprog.filter = compat_ptr(uprog32.filter); 633 return get_filter(&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(&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(&pch->upl); 652 return -EALREADY; 653 } 654 refcount_inc(&pchb->file.refcnt); 655 rcu_assign_pointer(pch->bridge, pchb); 656 spin_unlock(&pch->upl); 657 658 spin_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(&pchb->upl); 662 goto err_unset; 663 } 664 refcount_inc(&pch->file.refcnt); 665 rcu_assign_pointer(pchb->bridge, pch); 666 spin_unlock(&pchb->upl); 667 668 return 0; 669 670err_unset: 671 spin_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(&pch->upl); 676 synchronize_rcu(); 677 678 if (pchb) 679 if (refcount_dec_and_test(&pchb->file.refcnt)) 680 ppp_destroy_channel(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(&pch->upl); 690 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 691 if (!pchb) { 692 spin_unlock(&pch->upl); 693 return -EINVAL; 694 } 695 RCU_INIT_POINTER(pch->bridge, NULL); 696 spin_unlock(&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(&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(&pchb->upl); 708 709 synchronize_rcu(); 710 711 if (pchbb == pch) 712 if (refcount_dec_and_test(&pch->file.refcnt)) 713 ppp_destroy_channel(pch); 714 715 if (refcount_dec_and_test(&pchb->file.refcnt)) 716 ppp_destroy_channel(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(&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(&pchb->file.refcnt); 785 spin_unlock_bh(&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(&pchb->file.refcnt)) 791 ppp_destroy_channel(pchb); 792 break; 793 794 case PPPIOCUNBRIDGECHAN: 795 err = ppp_unbridge_channels(pch); 796 break; 797 798 default: 799 down_read(&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(&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(&data, argp, sizeof(data))) 852 err = -EFAULT; 853 else 854 err = ppp_set_compress(ppp, &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(argp, &idle32, 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(argp, &idle64, 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(val2+1, val+1); 901 if (IS_ERR(vj)) { 902 err = PTR_ERR(vj); 903 break; 904 } 905 ppp_lock(ppp); 906 if (ppp->vj) 907 slhc_free(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(&npi, argp, sizeof(npi))) 916 break; 917 err = proto_to_npindex(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(argp, &npi, 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(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(argp); 939 struct bpf_prog **which; 940 941 if (IS_ERR(filter)) { 942 err = PTR_ERR(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(*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(&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(argp); 1005 struct bpf_prog **which; 1006 1007 if (IS_ERR(filter)) { 1008 err = PTR_ERR(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(*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(&data32, argp, sizeof(data32))) { 1028 err = -EFAULT; 1029 } else { 1030 struct ppp_option_data data = { 1031 .ptr = compat_ptr(data32.ptr), 1032 .length = data32.length, 1033 .transmit = data32.transmit 1034 }; 1035 err = ppp_set_compress(ppp, &data); 1036 } 1037 break; 1038 } 1039 } 1040 } 1041 mutex_unlock(&ppp_mutex); 1042 1043 /* all other commands have compatible arguments */ 1044 if (err == -ENOIOCTLCMD) 1045 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(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); 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(&ppp->file.refcnt); 1085 file->private_data = &ppp->file; 1086 err = 0; 1087 } 1088 mutex_unlock(&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(&pn->all_channels_lock); 1097 chan = ppp_find_channel(pn, unit); 1098 if (chan) { 1099 refcount_inc(&chan->file.refcnt); 1100 file->private_data = &chan->file; 1101 err = 0; 1102 } 1103 spin_unlock_bh(&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, ppp_net_id); 1132 1133 idr_init(&pn->units_idr); 1134 mutex_init(&pn->all_ppp_mutex); 1135 1136 INIT_LIST_HEAD(&pn->all_channels); 1137 INIT_LIST_HEAD(&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, 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(ppp->dev, dev_to_kill); 1153} 1154 1155static __net_exit void ppp_exit_net(struct net *net) 1156{ 1157 struct ppp_net *pn = net_generic(net, ppp_net_id); 1158 1159 mutex_destroy(&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(ppp->ppp_net); 1176 int ret; 1177 1178 mutex_lock(&pn->all_ppp_mutex); 1179 1180 if (unit < 0) { 1181 ret = unit_get(&pn->units_idr, ppp, 0); 1182 if (ret < 0) 1183 goto err; 1184 if (!ifname_is_set) { 1185 while (1) { 1186 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret); 1187 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name)) 1188 break; 1189 unit_put(&pn->units_idr, ret); 1190 ret = unit_get(&pn->units_idr, ppp, 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(&pn->units_idr, unit)) { 1202 ret = -EEXIST; 1203 goto err; 1204 } 1205 ret = unit_set(&pn->units_idr, ppp, 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(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index); 1216 1217 mutex_unlock(&pn->all_ppp_mutex); 1218 1219 ret = register_netdevice(ppp->dev); 1220 if (ret < 0) 1221 goto err_unit; 1222 1223 atomic_inc(&ppp_unit_count); 1224 1225 return 0; 1226 1227err_unit: 1228 mutex_lock(&pn->all_ppp_mutex); 1229 unit_put(&pn->units_idr, ppp->file.index); 1230err: 1231 mutex_unlock(&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(&ppp->file, 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(&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(&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, conf->unit, 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(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(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(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(nla_get_s32(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(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME])) 1352 conf.ifname_is_set = false; 1353 1354 err = ppp_dev_configure(link_net, dev, &conf); 1355 1356out_unlock: 1357 mutex_unlock(&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, "ppp", &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(&ppp_class); 1423 if (err) 1424 goto out_chrdev; 1425 1426 err = rtnl_link_register(&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(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp"); 1434 1435 return 0; 1436 1437out_class: 1438 class_unregister(&ppp_class); 1439out_chrdev: 1440 unregister_chrdev(PPP_MAJOR, "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, 2); 1480 proto = npindex_to_proto[npi]; 1481 put_unaligned_be16(proto, pp); 1482 1483 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, 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, &stats); 1507 if (copy_to_user(addr, &stats, 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(addr, &cstats, sizeof(cstats))) 1519 break; 1520 err = 0; 1521 break; 1522 1523 case SIOCGPPPVER: 1524 vers = PPP_VERSION; 1525 if (copy_to_user(addr, 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(stats64, 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(&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(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(&pn->units_idr, ppp->file.index); 1575 mutex_unlock(&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(&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(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(&ppp->file.xq, skb); 1660 while (!ppp->xmit_pending && 1661 (skb = skb_dequeue(&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(&ppp->file.xq)) 1666 netif_wake_queue(ppp->dev); 1667 else 1668 netif_stop_queue(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(ppp->dev, "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(new_skb_size, GFP_ATOMIC); 1714 if (!new_skb) { 1715 if (net_ratelimit()) 1716 netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n"); 1717 return NULL; 1718 } 1719 if (ppp->dev->hard_header_len > PPP_HDRLEN) 1720 skb_reserve(new_skb, 1721 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, 2); /* pull off A/C bytes */ 1732 } else if (len == 0) { 1733 /* didn't compress, or CCP not up yet */ 1734 consume_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(ppp->dev, "ppp: compressor dropped pkt\n"); 1747 consume_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, 2) = htons(PPP_FILTER_OUTBOUND_TAG); 1774 if (ppp->pass_filter && 1775 bpf_prog_run(ppp->pass_filter, skb) == 0) { 1776 if (ppp->debug & 1) 1777 netdev_printk(KERN_DEBUG, ppp->dev, 1778 "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(ppp->active_filter, skb) == 0)) 1786 ppp->last_xmit = jiffies; 1787 skb_pull(skb, 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(ppp->dev, 1, 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(skb->len + ppp->dev->hard_header_len - 2, 1802 GFP_ATOMIC); 1803 if (!new_skb) { 1804 netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n"); 1805 goto drop; 1806 } 1807 skb_reserve(new_skb, ppp->dev->hard_header_len - 2); 1808 cp = skb->data + 2; 1809 len = slhc_compress(ppp->vj, cp, skb->len - 2, 1810 new_skb->data + 2, &cp, 1811 !(ppp->flags & SC_NO_TCP_CCID)); 1812 if (cp == skb->data + 2) { 1813 /* didn't compress */ 1814 consume_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 + 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, 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(ppp->dev, 1843 "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(&ppp->file.rq, 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(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(&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(&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(&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(&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(&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(&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(flen + hdrlen + (flen == 0), GFP_ATOMIC); 2116 if (!frag) 2117 goto noskb; 2118 q = skb_put(frag, flen + hdrlen); 2119 2120 /* make the MP header */ 2121 put_unaligned_be16(PPP_MP, 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(&pch->file.xq) || 2137 !chan->ops->start_xmit(chan, frag)) 2138 skb_queue_tail(&pch->file.xq, frag); 2139 pch->had_frag = 1; 2140 p += flen; 2141 len -= flen; 2142 ++ppp->nxseq; 2143 bits = 0; 2144 spin_unlock(&pch->downl); 2145 } 2146 ppp->nxchan = i; 2147 2148 return 1; 2149 2150 noskb: 2151 spin_unlock(&pch->downl); 2152 if (ppp->debug & 1) 2153 netdev_err(ppp->dev, "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(&pch->downl); 2166 if (pch->chan) { 2167 while (!skb_queue_empty(&pch->file.xq)) { 2168 skb = skb_dequeue(&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(&pch->file.xq, skb); 2172 break; 2173 } 2174 } 2175 } else { 2176 /* channel got deregistered */ 2177 skb_queue_purge(&pch->file.xq); 2178 } 2179 spin_unlock(&pch->downl); 2180 /* see if there is anything from the attached unit to be sent */ 2181 if (skb_queue_empty(&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, 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, 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, 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(&pchb->downl); 2283 if (!pchb->chan) { 2284 /* channel got unregistered */ 2285 kfree_skb(skb); 2286 goto outl; 2287 } 2288 2289 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net)); 2290 if (!pchb->chan->ops->start_xmit(pchb->chan, skb)) 2291 kfree_skb(skb); 2292 2293outl: 2294 spin_unlock_bh(&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(&pch->file.rq, skb); 2333 /* drop old frames if queue too long */ 2334 while (pch->file.rq.qlen > PPP_MAX_RQLEN && 2335 (skb = skb_dequeue(&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(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(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(skb->len + 128); 2432 if (!ns) { 2433 netdev_err(ppp->dev, "PPP: no memory " 2434 "(VJ decomp)\n"); 2435 goto err; 2436 } 2437 skb_reserve(ns, 2); 2438 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); 2439 consume_skb(skb); 2440 skb = ns; 2441 } 2442 else 2443 skb->ip_summed = CHECKSUM_NONE; 2444 2445 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2); 2446 if (len <= 0) { 2447 netdev_printk(KERN_DEBUG, ppp->dev, 2448 "PPP: VJ decompression error\n"); 2449 goto err; 2450 } 2451 len += 2; 2452 if (len > skb->len) 2453 skb_put(skb, 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, skb->len)) 2467 goto err; 2468 2469 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) { 2470 netdev_err(ppp->dev, "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, 1); 2478 break; 2479 } 2480 2481 dev_sw_netstats_rx_add(ppp->dev, 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(&ppp->file.rq, skb); 2487 /* limit queue length by dropping old frames */ 2488 while (ppp->file.rq.qlen > PPP_MAX_RQLEN && 2489 (skb = skb_dequeue(&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, 2) = htons(PPP_FILTER_INBOUND_TAG); 2505 if (ppp->pass_filter && 2506 bpf_prog_run(ppp->pass_filter, skb) == 0) { 2507 if (ppp->debug & 1) 2508 netdev_printk(KERN_DEBUG, ppp->dev, 2509 "PPP: inbound frame " 2510 "not passed\n"); 2511 kfree_skb(skb); 2512 return; 2513 } 2514 if (!(ppp->active_filter && 2515 bpf_prog_run(ppp->active_filter, skb) == 0)) 2516 ppp->last_recv = jiffies; 2517 __skb_pull(skb, 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, 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, !net_eq(ppp->ppp_net, 2532 dev_net(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, 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(obuff_size); 2569 if (!ns) { 2570 netdev_err(ppp->dev, "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(ns); 2583 goto err; 2584 } 2585 2586 consume_skb(skb); 2587 skb = ns; 2588 skb_put(skb, len); 2589 skb_pull(skb, 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, 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, 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(&ppp->mrq) >= PPP_MP_MAX_QLEN) { 2689 struct sk_buff *mskb = skb_peek(&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, 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, p, 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); 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(ppp->dev, "ppp_mp_reconstruct bad " 2758 "seq %u < %u\n", 2759 PPP_MP_CB(p)->sequence, seq); 2760 __skb_unlink(p, list); 2761 kfree_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, ppp->dev, 2778 "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, ppp->dev, 2807 "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, ppp->dev, 2827 "discarding frag %u\n", 2828 PPP_MP_CB(p)->sequence); 2829 __skb_unlink(p, list); 2830 kfree_skb(p); 2831 } 2832 head = skb_peek(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, ppp->dev, 2849 "discarding frag %u\n", 2850 PPP_MP_CB(p)->sequence); 2851 __skb_unlink(p, list); 2852 kfree_skb(p); 2853 } 2854 2855 if (ppp->debug & 1) 2856 netdev_printk(KERN_DEBUG, ppp->dev, 2857 " 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, head); 2868 __skb_unlink(skb, list); 2869 skb_queue_walk_from_safe(list, p, tmp) { 2870 __skb_unlink(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, &pch->ns_tracker, GFP_KERNEL); 2917 chan->ppp = pch; 2918 init_ppp_file(&pch->file, 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(&pn->all_channels_lock); 2928 pch->file.index = ++pn->last_channel_index; 2929 list_add(&pch->list, &pn->new_channels); 2930 atomic_inc(&channel_count); 2931 spin_unlock_bh(&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(&pch->chan_sem); 3007 spin_lock_bh(&pch->downl); 3008 WRITE_ONCE(pch->chan, NULL); 3009 spin_unlock_bh(&pch->downl); 3010 up_write(&pch->chan_sem); 3011 ppp_disconnect_channel(pch); 3012 3013 pn = ppp_pernet(pch->chan_net); 3014 spin_lock_bh(&pn->all_channels_lock); 3015 list_del(&pch->list); 3016 spin_unlock_bh(&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(&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(ccp_option, data->ptr, 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(ocomp->owner); 3083 } 3084 err = 0; 3085 } else 3086 module_put(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(ocomp->owner); 3101 } 3102 err = 0; 3103 } else 3104 module_put(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 + 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(xcomp->owner); 3221 } 3222 if (rstate) { 3223 rcomp->decomp_free(rstate); 3224 module_put(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(&compressor_list_lock); 3256 ret = -EEXIST; 3257 if (find_comp_entry(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(&ce->list, &compressor_list); 3266 out: 3267 spin_unlock(&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(&compressor_list_lock); 3278 ce = find_comp_entry(cp->compress_proto); 3279 if (ce && ce->comp == cp) { 3280 list_del(&ce->list); 3281 kfree(ce); 3282 } 3283 spin_unlock(&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(&compressor_list_lock); 3294 ce = find_comp_entry(type); 3295 if (ce) { 3296 cp = ce->comp; 3297 if (!try_module_get(cp->owner)) 3298 cp = NULL; 3299 } 3300 spin_unlock(&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->rx_packets); 3320 rx_bytes = u64_stats_read(&p->rx_bytes); 3321 tx_packets = u64_stats_read(&p->tx_packets); 3322 tx_bytes = u64_stats_read(&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(net, dev, &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(&pf->xq); 3399 skb_queue_head_init(&pf->rq); 3400 refcount_set(&pf->refcnt, 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(&ppp_unit_count); 3412 3413 if (!ppp->file.dead || ppp->n_channels) { 3414 /* "can't happen" */ 3415 netdev_err(ppp->dev, "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(ppp->vj); 3424 ppp->vj = NULL; 3425 } 3426 skb_queue_purge(&ppp->file.xq); 3427 skb_queue_purge(&ppp->file.rq); 3428#ifdef CONFIG_PPP_MULTILINK 3429 skb_queue_purge(&ppp->mrq); 3430#endif /* CONFIG_PPP_MULTILINK */ 3431#ifdef CONFIG_PPP_FILTER 3432 if (ppp->pass_filter) { 3433 bpf_prog_destroy(ppp->pass_filter); 3434 ppp->pass_filter = NULL; 3435 } 3436 3437 if (ppp->active_filter) { 3438 bpf_prog_destroy(ppp->active_filter); 3439 ppp->active_filter = NULL; 3440 } 3441#endif /* CONFIG_PPP_FILTER */ 3442 3443 kfree_skb(ppp->xmit_pending); 3444 free_percpu(ppp->xmit_recursion); 3445 3446 free_netdev(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(&pn->units_idr, 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(&pch->list, &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(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(&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(&pch->downl); 3512 if (!pch->chan) { 3513 /* Don't connect unregistered channels */ 3514 spin_unlock_bh(&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(&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(&pch->clist, &ppp->channels); 3530 ++ppp->n_channels; 3531 rcu_assign_pointer(pch->ppp, ppp); 3532 refcount_inc(&ppp->file.refcnt); 3533 ppp_unlock(ppp); 3534 ret = 0; 3535 3536 outl: 3537 spin_unlock(&pch->upl); 3538 out: 3539 mutex_unlock(&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(&pch->upl); 3553 ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl)); 3554 spin_unlock(&pch->upl); 3555 if (ppp) { 3556 /* remove it from the ppp unit's list */ 3557 ppp_lock(ppp); 3558 list_del_rcu(&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(&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(pch->chan_net, &pch->ns_tracker); 3576 pch->chan_net = NULL; 3577 3578 atomic_dec(&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(&pch->file.xq); 3586 skb_queue_purge(&pch->file.rq); 3587 kfree(pch); 3588} 3589 3590static void __exit ppp_cleanup(void) 3591{ 3592 /* should never happen */ 3593 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count)) 3594 pr_err("PPP: removing module but units remain!\n"); 3595 rtnl_link_unregister(&ppp_link_ops); 3596 unregister_chrdev(PPP_MAJOR, "ppp"); 3597 device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0)); 3598 class_unregister(&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, n, 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, min, 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, 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, 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");
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