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