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 struct rcu_head rcu; /* for RCU-deferred free of the channel */ 188 #ifdef CONFIG_PPP_MULTILINK 189 u8 avail; /* flag used in multilink stuff */ 190 u8 had_frag; /* >= 1 fragments have been sent */ 191 u32 lastseq; /* MP: last sequence # received */ 192 int speed; /* speed of the corresponding ppp channel*/ 193 #endif /* CONFIG_PPP_MULTILINK */ 194 }; 195 196 struct ppp_config { 197 struct file *file; 198 s32 unit; 199 bool ifname_is_set; 200 }; 201 202 /* 203 * SMP locking issues: 204 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels 205 * list and the ppp.n_channels field, you need to take both locks 206 * before you modify them. 207 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock -> 208 * channel.downl. 209 */ 210 211 static DEFINE_MUTEX(ppp_mutex); 212 static atomic_t ppp_unit_count = ATOMIC_INIT(0); 213 static atomic_t channel_count = ATOMIC_INIT(0); 214 215 /* per-net private data for this module */ 216 static unsigned int ppp_net_id __read_mostly; 217 struct ppp_net { 218 /* units to ppp mapping */ 219 struct idr units_idr; 220 221 /* 222 * all_ppp_mutex protects the units_idr mapping. 223 * It also ensures that finding a ppp unit in the units_idr 224 * map and updating its file.refcnt field is atomic. 225 */ 226 struct mutex all_ppp_mutex; 227 228 /* channels */ 229 struct list_head all_channels; 230 struct list_head new_channels; 231 int last_channel_index; 232 233 /* 234 * all_channels_lock protects all_channels and 235 * last_channel_index, and the atomicity of find 236 * a channel and updating its file.refcnt field. 237 */ 238 spinlock_t all_channels_lock; 239 }; 240 241 /* Get the PPP protocol number from a skb */ 242 #define PPP_PROTO(skb) get_unaligned_be16((skb)->data) 243 244 /* We limit the length of ppp->file.rq to this (arbitrary) value */ 245 #define PPP_MAX_RQLEN 32 246 247 /* 248 * Maximum number of multilink fragments queued up. 249 * This has to be large enough to cope with the maximum latency of 250 * the slowest channel relative to the others. Strictly it should 251 * depend on the number of channels and their characteristics. 252 */ 253 #define PPP_MP_MAX_QLEN 128 254 255 /* Multilink header bits. */ 256 #define B 0x80 /* this fragment begins a packet */ 257 #define E 0x40 /* this fragment ends a packet */ 258 259 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */ 260 #define seq_before(a, b) ((s32)((a) - (b)) < 0) 261 #define seq_after(a, b) ((s32)((a) - (b)) > 0) 262 263 /* Prototypes. */ 264 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, 265 struct file *file, unsigned int cmd, unsigned long arg); 266 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb); 267 static int ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb); 268 static int ppp_push(struct ppp *ppp, struct sk_buff *skb); 269 static void ppp_channel_push(struct channel *pch); 270 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, 271 struct channel *pch); 272 static void ppp_receive_error(struct ppp *ppp); 273 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb); 274 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp, 275 struct sk_buff *skb); 276 #ifdef CONFIG_PPP_MULTILINK 277 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, 278 struct channel *pch); 279 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb); 280 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp); 281 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb); 282 #endif /* CONFIG_PPP_MULTILINK */ 283 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data); 284 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound); 285 static void ppp_ccp_closed(struct ppp *ppp); 286 static struct compressor *find_compressor(int type); 287 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st); 288 static int ppp_create_interface(struct net *net, struct file *file, int *unit); 289 static void init_ppp_file(struct ppp_file *pf, int kind); 290 static void ppp_release_interface(struct ppp *ppp); 291 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit); 292 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit); 293 static int ppp_connect_channel(struct channel *pch, int unit); 294 static int ppp_disconnect_channel(struct channel *pch); 295 static void ppp_release_channel(struct channel *pch); 296 static int unit_get(struct idr *p, void *ptr, int min); 297 static int unit_set(struct idr *p, void *ptr, int n); 298 static void unit_put(struct idr *p, int n); 299 static void *unit_find(struct idr *p, int n); 300 static void ppp_setup(struct net_device *dev); 301 302 static const struct net_device_ops ppp_netdev_ops; 303 304 static const struct class ppp_class = { 305 .name = "ppp", 306 }; 307 308 /* per net-namespace data */ 309 static inline struct ppp_net *ppp_pernet(struct net *net) 310 { 311 return net_generic(net, ppp_net_id); 312 } 313 314 /* Translates a PPP protocol number to a NP index (NP == network protocol) */ 315 static inline int proto_to_npindex(int proto) 316 { 317 switch (proto) { 318 case PPP_IP: 319 return NP_IP; 320 case PPP_IPV6: 321 return NP_IPV6; 322 case PPP_IPX: 323 return NP_IPX; 324 case PPP_AT: 325 return NP_AT; 326 case PPP_MPLS_UC: 327 return NP_MPLS_UC; 328 case PPP_MPLS_MC: 329 return NP_MPLS_MC; 330 } 331 return -EINVAL; 332 } 333 334 /* Translates an NP index into a PPP protocol number */ 335 static const int npindex_to_proto[NUM_NP] = { 336 PPP_IP, 337 PPP_IPV6, 338 PPP_IPX, 339 PPP_AT, 340 PPP_MPLS_UC, 341 PPP_MPLS_MC, 342 }; 343 344 /* Translates an ethertype into an NP index */ 345 static inline int ethertype_to_npindex(int ethertype) 346 { 347 switch (ethertype) { 348 case ETH_P_IP: 349 return NP_IP; 350 case ETH_P_IPV6: 351 return NP_IPV6; 352 case ETH_P_IPX: 353 return NP_IPX; 354 case ETH_P_PPPTALK: 355 case ETH_P_ATALK: 356 return NP_AT; 357 case ETH_P_MPLS_UC: 358 return NP_MPLS_UC; 359 case ETH_P_MPLS_MC: 360 return NP_MPLS_MC; 361 } 362 return -1; 363 } 364 365 /* Translates an NP index into an ethertype */ 366 static const int npindex_to_ethertype[NUM_NP] = { 367 ETH_P_IP, 368 ETH_P_IPV6, 369 ETH_P_IPX, 370 ETH_P_PPPTALK, 371 ETH_P_MPLS_UC, 372 ETH_P_MPLS_MC, 373 }; 374 375 /* 376 * Locking shorthand. 377 */ 378 #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock) 379 #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock) 380 #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock) 381 #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock) 382 #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \ 383 ppp_recv_lock(ppp); } while (0) 384 #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \ 385 ppp_xmit_unlock(ppp); } while (0) 386 387 /* 388 * /dev/ppp device routines. 389 * The /dev/ppp device is used by pppd to control the ppp unit. 390 * It supports the read, write, ioctl and poll functions. 391 * Open instances of /dev/ppp can be in one of three states: 392 * unattached, attached to a ppp unit, or attached to a ppp channel. 393 */ 394 static int ppp_open(struct inode *inode, struct file *file) 395 { 396 /* 397 * This could (should?) be enforced by the permissions on /dev/ppp. 398 */ 399 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN)) 400 return -EPERM; 401 return 0; 402 } 403 404 static int ppp_release(struct inode *unused, struct file *file) 405 { 406 struct ppp_file *pf = file->private_data; 407 struct ppp *ppp; 408 409 if (pf) { 410 file->private_data = NULL; 411 switch (pf->kind) { 412 case INTERFACE: 413 ppp = PF_TO_PPP(pf); 414 rtnl_lock(); 415 if (file == ppp->owner) 416 unregister_netdevice(ppp->dev); 417 rtnl_unlock(); 418 ppp_release_interface(ppp); 419 break; 420 case CHANNEL: 421 ppp_release_channel(PF_TO_CHANNEL(pf)); 422 break; 423 } 424 } 425 return 0; 426 } 427 428 static ssize_t ppp_read(struct file *file, char __user *buf, 429 size_t count, loff_t *ppos) 430 { 431 struct ppp_file *pf = file->private_data; 432 DECLARE_WAITQUEUE(wait, current); 433 ssize_t ret; 434 struct sk_buff *skb = NULL; 435 struct iovec iov; 436 struct iov_iter to; 437 438 ret = count; 439 440 if (!pf) 441 return -ENXIO; 442 add_wait_queue(&pf->rwait, &wait); 443 for (;;) { 444 set_current_state(TASK_INTERRUPTIBLE); 445 skb = skb_dequeue(&pf->rq); 446 if (skb) 447 break; 448 ret = 0; 449 if (pf->dead) 450 break; 451 if (pf->kind == INTERFACE) { 452 /* 453 * Return 0 (EOF) on an interface that has no 454 * channels connected, unless it is looping 455 * network traffic (demand mode). 456 */ 457 struct ppp *ppp = PF_TO_PPP(pf); 458 459 ppp_recv_lock(ppp); 460 if (ppp->n_channels == 0 && 461 (ppp->flags & SC_LOOP_TRAFFIC) == 0) { 462 ppp_recv_unlock(ppp); 463 break; 464 } 465 ppp_recv_unlock(ppp); 466 } 467 ret = -EAGAIN; 468 if (file->f_flags & O_NONBLOCK) 469 break; 470 ret = -ERESTARTSYS; 471 if (signal_pending(current)) 472 break; 473 schedule(); 474 } 475 set_current_state(TASK_RUNNING); 476 remove_wait_queue(&pf->rwait, &wait); 477 478 if (!skb) 479 goto out; 480 481 ret = -EOVERFLOW; 482 if (skb->len > count) 483 goto outf; 484 ret = -EFAULT; 485 iov.iov_base = buf; 486 iov.iov_len = count; 487 iov_iter_init(&to, ITER_DEST, &iov, 1, count); 488 if (skb_copy_datagram_iter(skb, 0, &to, skb->len)) 489 goto outf; 490 ret = skb->len; 491 492 outf: 493 kfree_skb(skb); 494 out: 495 return ret; 496 } 497 498 static bool ppp_check_packet(struct sk_buff *skb, size_t count) 499 { 500 /* LCP packets must include LCP header which 4 bytes long: 501 * 1-byte code, 1-byte identifier, and 2-byte length. 502 */ 503 return get_unaligned_be16(skb->data) != PPP_LCP || 504 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN; 505 } 506 507 static ssize_t ppp_write(struct file *file, const char __user *buf, 508 size_t count, loff_t *ppos) 509 { 510 struct ppp_file *pf = file->private_data; 511 struct sk_buff *skb; 512 ssize_t ret; 513 514 if (!pf) 515 return -ENXIO; 516 /* All PPP packets should start with the 2-byte protocol */ 517 if (count < PPP_PROTO_LEN) 518 return -EINVAL; 519 ret = -ENOMEM; 520 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL); 521 if (!skb) 522 goto out; 523 skb_reserve(skb, pf->hdrlen); 524 ret = -EFAULT; 525 if (copy_from_user(skb_put(skb, count), buf, count)) { 526 kfree_skb(skb); 527 goto out; 528 } 529 ret = -EINVAL; 530 if (unlikely(!ppp_check_packet(skb, count))) { 531 kfree_skb(skb); 532 goto out; 533 } 534 535 switch (pf->kind) { 536 case INTERFACE: 537 ppp_xmit_process(PF_TO_PPP(pf), skb); 538 break; 539 case CHANNEL: 540 skb_queue_tail(&pf->xq, skb); 541 ppp_channel_push(PF_TO_CHANNEL(pf)); 542 break; 543 } 544 545 ret = count; 546 547 out: 548 return ret; 549 } 550 551 /* No kernel lock - fine */ 552 static __poll_t ppp_poll(struct file *file, poll_table *wait) 553 { 554 struct ppp_file *pf = file->private_data; 555 __poll_t mask; 556 557 if (!pf) 558 return 0; 559 poll_wait(file, &pf->rwait, wait); 560 mask = EPOLLOUT | EPOLLWRNORM; 561 if (skb_peek(&pf->rq)) 562 mask |= EPOLLIN | EPOLLRDNORM; 563 if (pf->dead) 564 mask |= EPOLLHUP; 565 else if (pf->kind == INTERFACE) { 566 /* see comment in ppp_read */ 567 struct ppp *ppp = PF_TO_PPP(pf); 568 569 ppp_recv_lock(ppp); 570 if (ppp->n_channels == 0 && 571 (ppp->flags & SC_LOOP_TRAFFIC) == 0) 572 mask |= EPOLLIN | EPOLLRDNORM; 573 ppp_recv_unlock(ppp); 574 } 575 576 return mask; 577 } 578 579 #ifdef CONFIG_PPP_FILTER 580 static struct bpf_prog *get_filter(struct sock_fprog *uprog) 581 { 582 struct sock_fprog_kern fprog; 583 struct bpf_prog *res = NULL; 584 int err; 585 586 if (!uprog->len) 587 return NULL; 588 589 /* uprog->len is unsigned short, so no overflow here */ 590 fprog.len = uprog->len; 591 fprog.filter = memdup_array_user(uprog->filter, 592 uprog->len, sizeof(struct sock_filter)); 593 if (IS_ERR(fprog.filter)) 594 return ERR_CAST(fprog.filter); 595 596 err = bpf_prog_create(&res, &fprog); 597 kfree(fprog.filter); 598 599 return err ? ERR_PTR(err) : res; 600 } 601 602 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p) 603 { 604 struct sock_fprog uprog; 605 606 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog))) 607 return ERR_PTR(-EFAULT); 608 return get_filter(&uprog); 609 } 610 611 #ifdef CONFIG_COMPAT 612 struct sock_fprog32 { 613 unsigned short len; 614 compat_caddr_t filter; 615 }; 616 617 #define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32) 618 #define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32) 619 620 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p) 621 { 622 struct sock_fprog32 uprog32; 623 struct sock_fprog uprog; 624 625 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32))) 626 return ERR_PTR(-EFAULT); 627 uprog.len = uprog32.len; 628 uprog.filter = compat_ptr(uprog32.filter); 629 return get_filter(&uprog); 630 } 631 #endif 632 #endif 633 634 /* Bridge one PPP channel to another. 635 * When two channels are bridged, ppp_input on one channel is redirected to 636 * the other's ops->start_xmit handler. 637 * In order to safely bridge channels we must reject channels which are already 638 * part of a bridge instance, or which form part of an existing unit. 639 * Once successfully bridged, each channel holds a reference on the other 640 * to prevent it being freed while the bridge is extant. 641 */ 642 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb) 643 { 644 spin_lock(&pch->upl); 645 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) || 646 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) { 647 spin_unlock(&pch->upl); 648 return -EALREADY; 649 } 650 refcount_inc(&pchb->file.refcnt); 651 rcu_assign_pointer(pch->bridge, pchb); 652 spin_unlock(&pch->upl); 653 654 spin_lock(&pchb->upl); 655 if (rcu_dereference_protected(pchb->ppp, lockdep_is_held(&pchb->upl)) || 656 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) { 657 spin_unlock(&pchb->upl); 658 goto err_unset; 659 } 660 refcount_inc(&pch->file.refcnt); 661 rcu_assign_pointer(pchb->bridge, pch); 662 spin_unlock(&pchb->upl); 663 664 return 0; 665 666 err_unset: 667 spin_lock(&pch->upl); 668 /* Re-read pch->bridge with upl held in case it was modified concurrently */ 669 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 670 RCU_INIT_POINTER(pch->bridge, NULL); 671 spin_unlock(&pch->upl); 672 synchronize_rcu(); 673 674 if (pchb) 675 ppp_release_channel(pchb); 676 677 return -EALREADY; 678 } 679 680 static int ppp_unbridge_channels(struct channel *pch) 681 { 682 struct channel *pchb, *pchbb; 683 684 spin_lock(&pch->upl); 685 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 686 if (!pchb) { 687 spin_unlock(&pch->upl); 688 return -EINVAL; 689 } 690 RCU_INIT_POINTER(pch->bridge, NULL); 691 spin_unlock(&pch->upl); 692 693 /* Only modify pchb if phcb->bridge points back to pch. 694 * If not, it implies that there has been a race unbridging (and possibly 695 * even rebridging) pchb. We should leave pchb alone to avoid either a 696 * refcount underflow, or breaking another established bridge instance. 697 */ 698 spin_lock(&pchb->upl); 699 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl)); 700 if (pchbb == pch) 701 RCU_INIT_POINTER(pchb->bridge, NULL); 702 spin_unlock(&pchb->upl); 703 704 synchronize_rcu(); 705 706 if (pchbb == pch) 707 ppp_release_channel(pch); 708 709 ppp_release_channel(pchb); 710 711 return 0; 712 } 713 714 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 715 { 716 struct ppp_file *pf; 717 struct ppp *ppp; 718 int err = -EFAULT, val, val2, i; 719 struct ppp_idle32 idle32; 720 struct ppp_idle64 idle64; 721 struct npioctl npi; 722 int unit, cflags; 723 struct slcompress *vj; 724 void __user *argp = (void __user *)arg; 725 int __user *p = argp; 726 727 mutex_lock(&ppp_mutex); 728 729 pf = file->private_data; 730 if (!pf) { 731 err = ppp_unattached_ioctl(current->nsproxy->net_ns, 732 pf, file, cmd, arg); 733 goto out; 734 } 735 736 if (cmd == PPPIOCDETACH) { 737 /* 738 * PPPIOCDETACH is no longer supported as it was heavily broken, 739 * and is only known to have been used by pppd older than 740 * ppp-2.4.2 (released November 2003). 741 */ 742 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n", 743 current->comm, current->pid); 744 err = -EINVAL; 745 goto out; 746 } 747 748 if (pf->kind == CHANNEL) { 749 struct channel *pch, *pchb; 750 struct ppp_channel *chan; 751 struct ppp_net *pn; 752 753 pch = PF_TO_CHANNEL(pf); 754 755 switch (cmd) { 756 case PPPIOCCONNECT: 757 if (get_user(unit, p)) 758 break; 759 err = ppp_connect_channel(pch, unit); 760 break; 761 762 case PPPIOCDISCONN: 763 err = ppp_disconnect_channel(pch); 764 break; 765 766 case PPPIOCBRIDGECHAN: 767 if (get_user(unit, p)) 768 break; 769 err = -ENXIO; 770 pn = ppp_pernet(current->nsproxy->net_ns); 771 spin_lock_bh(&pn->all_channels_lock); 772 pchb = ppp_find_channel(pn, unit); 773 /* Hold a reference to prevent pchb being freed while 774 * we establish the bridge. 775 */ 776 if (pchb) 777 refcount_inc(&pchb->file.refcnt); 778 spin_unlock_bh(&pn->all_channels_lock); 779 if (!pchb) 780 break; 781 err = ppp_bridge_channels(pch, pchb); 782 /* Drop earlier refcount now bridge establishment is complete */ 783 ppp_release_channel(pchb); 784 break; 785 786 case PPPIOCUNBRIDGECHAN: 787 err = ppp_unbridge_channels(pch); 788 break; 789 790 default: 791 down_read(&pch->chan_sem); 792 chan = pch->chan; 793 err = -ENOTTY; 794 if (chan && chan->ops->ioctl) 795 err = chan->ops->ioctl(chan, cmd, arg); 796 up_read(&pch->chan_sem); 797 } 798 goto out; 799 } 800 801 if (pf->kind != INTERFACE) { 802 /* can't happen */ 803 pr_err("PPP: not interface or channel??\n"); 804 err = -EINVAL; 805 goto out; 806 } 807 808 ppp = PF_TO_PPP(pf); 809 switch (cmd) { 810 case PPPIOCSMRU: 811 if (get_user(val, p)) 812 break; 813 ppp_recv_lock(ppp); 814 ppp->mru = val; 815 ppp_recv_unlock(ppp); 816 err = 0; 817 break; 818 819 case PPPIOCSFLAGS: 820 if (get_user(val, p)) 821 break; 822 ppp_lock(ppp); 823 cflags = ppp->flags & ~val; 824 #ifdef CONFIG_PPP_MULTILINK 825 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK)) 826 ppp->nextseq = 0; 827 #endif 828 ppp->flags = val & SC_FLAG_BITS; 829 ppp_unlock(ppp); 830 if (cflags & SC_CCP_OPEN) 831 ppp_ccp_closed(ppp); 832 err = 0; 833 break; 834 835 case PPPIOCGFLAGS: 836 ppp_lock(ppp); 837 val = ppp->flags | ppp->xstate | ppp->rstate; 838 ppp_unlock(ppp); 839 if (put_user(val, p)) 840 break; 841 err = 0; 842 break; 843 844 case PPPIOCSCOMPRESS: 845 { 846 struct ppp_option_data data; 847 if (copy_from_user(&data, argp, sizeof(data))) 848 err = -EFAULT; 849 else 850 err = ppp_set_compress(ppp, &data); 851 break; 852 } 853 case PPPIOCGUNIT: 854 if (put_user(ppp->file.index, p)) 855 break; 856 err = 0; 857 break; 858 859 case PPPIOCSDEBUG: 860 if (get_user(val, p)) 861 break; 862 WRITE_ONCE(ppp->debug, val); 863 err = 0; 864 break; 865 866 case PPPIOCGDEBUG: 867 if (put_user(ppp->debug, p)) 868 break; 869 err = 0; 870 break; 871 872 case PPPIOCGIDLE32: 873 idle32.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ; 874 idle32.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ; 875 if (copy_to_user(argp, &idle32, sizeof(idle32))) 876 break; 877 err = 0; 878 break; 879 880 case PPPIOCGIDLE64: 881 idle64.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ; 882 idle64.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ; 883 if (copy_to_user(argp, &idle64, sizeof(idle64))) 884 break; 885 err = 0; 886 break; 887 888 case PPPIOCSMAXCID: 889 if (get_user(val, p)) 890 break; 891 val2 = 15; 892 if ((val >> 16) != 0) { 893 val2 = val >> 16; 894 val &= 0xffff; 895 } 896 vj = slhc_init(val2+1, val+1); 897 if (IS_ERR(vj)) { 898 err = PTR_ERR(vj); 899 break; 900 } 901 ppp_lock(ppp); 902 if (ppp->vj) 903 slhc_free(ppp->vj); 904 ppp->vj = vj; 905 ppp_unlock(ppp); 906 err = 0; 907 break; 908 909 case PPPIOCGNPMODE: 910 case PPPIOCSNPMODE: 911 if (copy_from_user(&npi, argp, sizeof(npi))) 912 break; 913 err = proto_to_npindex(npi.protocol); 914 if (err < 0) 915 break; 916 i = err; 917 if (cmd == PPPIOCGNPMODE) { 918 err = -EFAULT; 919 npi.mode = ppp->npmode[i]; 920 if (copy_to_user(argp, &npi, sizeof(npi))) 921 break; 922 } else { 923 WRITE_ONCE(ppp->npmode[i], npi.mode); 924 /* we may be able to transmit more packets now (??) */ 925 netif_wake_queue(ppp->dev); 926 } 927 err = 0; 928 break; 929 930 #ifdef CONFIG_PPP_FILTER 931 case PPPIOCSPASS: 932 case PPPIOCSACTIVE: 933 { 934 struct bpf_prog *filter = ppp_get_filter(argp); 935 struct bpf_prog **which; 936 937 if (IS_ERR(filter)) { 938 err = PTR_ERR(filter); 939 break; 940 } 941 if (cmd == PPPIOCSPASS) 942 which = &ppp->pass_filter; 943 else 944 which = &ppp->active_filter; 945 ppp_lock(ppp); 946 if (*which) 947 bpf_prog_destroy(*which); 948 *which = filter; 949 ppp_unlock(ppp); 950 err = 0; 951 break; 952 } 953 #endif /* CONFIG_PPP_FILTER */ 954 955 #ifdef CONFIG_PPP_MULTILINK 956 case PPPIOCSMRRU: 957 if (get_user(val, p)) 958 break; 959 ppp_recv_lock(ppp); 960 ppp->mrru = val; 961 ppp_recv_unlock(ppp); 962 err = 0; 963 break; 964 #endif /* CONFIG_PPP_MULTILINK */ 965 966 default: 967 err = -ENOTTY; 968 } 969 970 out: 971 mutex_unlock(&ppp_mutex); 972 973 return err; 974 } 975 976 #ifdef CONFIG_COMPAT 977 struct ppp_option_data32 { 978 compat_uptr_t ptr; 979 u32 length; 980 compat_int_t transmit; 981 }; 982 #define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32) 983 984 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 985 { 986 struct ppp_file *pf; 987 int err = -ENOIOCTLCMD; 988 void __user *argp = (void __user *)arg; 989 990 mutex_lock(&ppp_mutex); 991 992 pf = file->private_data; 993 if (pf && pf->kind == INTERFACE) { 994 struct ppp *ppp = PF_TO_PPP(pf); 995 switch (cmd) { 996 #ifdef CONFIG_PPP_FILTER 997 case PPPIOCSPASS32: 998 case PPPIOCSACTIVE32: 999 { 1000 struct bpf_prog *filter = compat_ppp_get_filter(argp); 1001 struct bpf_prog **which; 1002 1003 if (IS_ERR(filter)) { 1004 err = PTR_ERR(filter); 1005 break; 1006 } 1007 if (cmd == PPPIOCSPASS32) 1008 which = &ppp->pass_filter; 1009 else 1010 which = &ppp->active_filter; 1011 ppp_lock(ppp); 1012 if (*which) 1013 bpf_prog_destroy(*which); 1014 *which = filter; 1015 ppp_unlock(ppp); 1016 err = 0; 1017 break; 1018 } 1019 #endif /* CONFIG_PPP_FILTER */ 1020 case PPPIOCSCOMPRESS32: 1021 { 1022 struct ppp_option_data32 data32; 1023 if (copy_from_user(&data32, argp, sizeof(data32))) { 1024 err = -EFAULT; 1025 } else { 1026 struct ppp_option_data data = { 1027 .ptr = compat_ptr(data32.ptr), 1028 .length = data32.length, 1029 .transmit = data32.transmit 1030 }; 1031 err = ppp_set_compress(ppp, &data); 1032 } 1033 break; 1034 } 1035 } 1036 } 1037 mutex_unlock(&ppp_mutex); 1038 1039 /* all other commands have compatible arguments */ 1040 if (err == -ENOIOCTLCMD) 1041 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1042 1043 return err; 1044 } 1045 #endif 1046 1047 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, 1048 struct file *file, unsigned int cmd, unsigned long arg) 1049 { 1050 int unit, err = -EFAULT; 1051 struct ppp *ppp; 1052 struct channel *chan; 1053 struct ppp_net *pn; 1054 int __user *p = (int __user *)arg; 1055 1056 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1057 return -EPERM; 1058 1059 switch (cmd) { 1060 case PPPIOCNEWUNIT: 1061 /* Create a new ppp unit */ 1062 if (get_user(unit, p)) 1063 break; 1064 err = ppp_create_interface(net, file, &unit); 1065 if (err < 0) 1066 break; 1067 1068 err = -EFAULT; 1069 if (put_user(unit, p)) 1070 break; 1071 err = 0; 1072 break; 1073 1074 case PPPIOCATTACH: 1075 /* Attach to an existing ppp unit */ 1076 if (get_user(unit, p)) 1077 break; 1078 err = -ENXIO; 1079 pn = ppp_pernet(net); 1080 mutex_lock(&pn->all_ppp_mutex); 1081 ppp = ppp_find_unit(pn, unit); 1082 if (ppp) { 1083 refcount_inc(&ppp->file.refcnt); 1084 file->private_data = &ppp->file; 1085 err = 0; 1086 } 1087 mutex_unlock(&pn->all_ppp_mutex); 1088 break; 1089 1090 case PPPIOCATTCHAN: 1091 if (get_user(unit, p)) 1092 break; 1093 err = -ENXIO; 1094 pn = ppp_pernet(net); 1095 spin_lock_bh(&pn->all_channels_lock); 1096 chan = ppp_find_channel(pn, unit); 1097 if (chan) { 1098 refcount_inc(&chan->file.refcnt); 1099 file->private_data = &chan->file; 1100 err = 0; 1101 } 1102 spin_unlock_bh(&pn->all_channels_lock); 1103 break; 1104 1105 default: 1106 err = -ENOTTY; 1107 } 1108 1109 return err; 1110 } 1111 1112 static const struct file_operations ppp_device_fops = { 1113 .owner = THIS_MODULE, 1114 .read = ppp_read, 1115 .write = ppp_write, 1116 .poll = ppp_poll, 1117 .unlocked_ioctl = ppp_ioctl, 1118 #ifdef CONFIG_COMPAT 1119 .compat_ioctl = ppp_compat_ioctl, 1120 #endif 1121 .open = ppp_open, 1122 .release = ppp_release, 1123 .llseek = noop_llseek, 1124 }; 1125 1126 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head); 1127 1128 static __net_init int ppp_init_net(struct net *net) 1129 { 1130 struct ppp_net *pn = net_generic(net, ppp_net_id); 1131 1132 idr_init(&pn->units_idr); 1133 mutex_init(&pn->all_ppp_mutex); 1134 1135 INIT_LIST_HEAD(&pn->all_channels); 1136 INIT_LIST_HEAD(&pn->new_channels); 1137 1138 spin_lock_init(&pn->all_channels_lock); 1139 1140 return 0; 1141 } 1142 1143 static __net_exit void ppp_exit_rtnl_net(struct net *net, 1144 struct list_head *dev_to_kill) 1145 { 1146 struct ppp_net *pn = net_generic(net, ppp_net_id); 1147 struct ppp *ppp; 1148 int id; 1149 1150 idr_for_each_entry(&pn->units_idr, ppp, id) 1151 ppp_nl_dellink(ppp->dev, dev_to_kill); 1152 } 1153 1154 static __net_exit void ppp_exit_net(struct net *net) 1155 { 1156 struct ppp_net *pn = net_generic(net, ppp_net_id); 1157 1158 mutex_destroy(&pn->all_ppp_mutex); 1159 idr_destroy(&pn->units_idr); 1160 WARN_ON_ONCE(!list_empty(&pn->all_channels)); 1161 WARN_ON_ONCE(!list_empty(&pn->new_channels)); 1162 } 1163 1164 static struct pernet_operations ppp_net_ops = { 1165 .init = ppp_init_net, 1166 .exit_rtnl = ppp_exit_rtnl_net, 1167 .exit = ppp_exit_net, 1168 .id = &ppp_net_id, 1169 .size = sizeof(struct ppp_net), 1170 }; 1171 1172 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set) 1173 { 1174 struct ppp_net *pn = ppp_pernet(ppp->ppp_net); 1175 int ret; 1176 1177 mutex_lock(&pn->all_ppp_mutex); 1178 1179 if (unit < 0) { 1180 ret = unit_get(&pn->units_idr, ppp, 0); 1181 if (ret < 0) 1182 goto err; 1183 if (!ifname_is_set) { 1184 while (1) { 1185 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret); 1186 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name)) 1187 break; 1188 unit_put(&pn->units_idr, ret); 1189 ret = unit_get(&pn->units_idr, ppp, ret + 1); 1190 if (ret < 0) 1191 goto err; 1192 } 1193 } 1194 } else { 1195 /* Caller asked for a specific unit number. Fail with -EEXIST 1196 * if unavailable. For backward compatibility, return -EEXIST 1197 * too if idr allocation fails; this makes pppd retry without 1198 * requesting a specific unit number. 1199 */ 1200 if (unit_find(&pn->units_idr, unit)) { 1201 ret = -EEXIST; 1202 goto err; 1203 } 1204 ret = unit_set(&pn->units_idr, ppp, unit); 1205 if (ret < 0) { 1206 /* Rewrite error for backward compatibility */ 1207 ret = -EEXIST; 1208 goto err; 1209 } 1210 } 1211 ppp->file.index = ret; 1212 1213 if (!ifname_is_set) 1214 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index); 1215 1216 mutex_unlock(&pn->all_ppp_mutex); 1217 1218 ret = register_netdevice(ppp->dev); 1219 if (ret < 0) 1220 goto err_unit; 1221 1222 atomic_inc(&ppp_unit_count); 1223 1224 return 0; 1225 1226 err_unit: 1227 mutex_lock(&pn->all_ppp_mutex); 1228 unit_put(&pn->units_idr, ppp->file.index); 1229 err: 1230 mutex_unlock(&pn->all_ppp_mutex); 1231 1232 return ret; 1233 } 1234 1235 static int ppp_dev_configure(struct net *src_net, struct net_device *dev, 1236 const struct ppp_config *conf) 1237 { 1238 struct ppp *ppp = netdev_priv(dev); 1239 int indx; 1240 int err; 1241 int cpu; 1242 1243 ppp->dev = dev; 1244 ppp->ppp_net = src_net; 1245 ppp->mru = PPP_MRU; 1246 ppp->owner = conf->file; 1247 1248 init_ppp_file(&ppp->file, INTERFACE); 1249 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */ 1250 1251 for (indx = 0; indx < NUM_NP; ++indx) 1252 ppp->npmode[indx] = NPMODE_PASS; 1253 INIT_LIST_HEAD(&ppp->channels); 1254 spin_lock_init(&ppp->rlock); 1255 spin_lock_init(&ppp->wlock); 1256 1257 ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion); 1258 if (!ppp->xmit_recursion) { 1259 err = -ENOMEM; 1260 goto err1; 1261 } 1262 for_each_possible_cpu(cpu) { 1263 struct ppp_xmit_recursion *xmit_recursion; 1264 1265 xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu); 1266 xmit_recursion->owner = NULL; 1267 local_lock_init(&xmit_recursion->bh_lock); 1268 } 1269 1270 #ifdef CONFIG_PPP_MULTILINK 1271 ppp->minseq = -1; 1272 skb_queue_head_init(&ppp->mrq); 1273 #endif /* CONFIG_PPP_MULTILINK */ 1274 #ifdef CONFIG_PPP_FILTER 1275 ppp->pass_filter = NULL; 1276 ppp->active_filter = NULL; 1277 #endif /* CONFIG_PPP_FILTER */ 1278 1279 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set); 1280 if (err < 0) 1281 goto err2; 1282 1283 conf->file->private_data = &ppp->file; 1284 1285 return 0; 1286 err2: 1287 free_percpu(ppp->xmit_recursion); 1288 err1: 1289 return err; 1290 } 1291 1292 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = { 1293 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 }, 1294 }; 1295 1296 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[], 1297 struct netlink_ext_ack *extack) 1298 { 1299 if (!data) 1300 return -EINVAL; 1301 1302 if (!data[IFLA_PPP_DEV_FD]) 1303 return -EINVAL; 1304 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0) 1305 return -EBADF; 1306 1307 return 0; 1308 } 1309 1310 static int ppp_nl_newlink(struct net_device *dev, 1311 struct rtnl_newlink_params *params, 1312 struct netlink_ext_ack *extack) 1313 { 1314 struct net *link_net = rtnl_newlink_link_net(params); 1315 struct nlattr **data = params->data; 1316 struct nlattr **tb = params->tb; 1317 struct ppp_config conf = { 1318 .unit = -1, 1319 .ifname_is_set = true, 1320 }; 1321 struct file *file; 1322 int err; 1323 1324 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD])); 1325 if (!file) 1326 return -EBADF; 1327 1328 /* rtnl_lock is already held here, but ppp_create_interface() locks 1329 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids 1330 * possible deadlock due to lock order inversion, at the cost of 1331 * pushing the problem back to userspace. 1332 */ 1333 if (!mutex_trylock(&ppp_mutex)) { 1334 err = -EBUSY; 1335 goto out; 1336 } 1337 1338 if (file->f_op != &ppp_device_fops || file->private_data) { 1339 err = -EBADF; 1340 goto out_unlock; 1341 } 1342 1343 conf.file = file; 1344 1345 /* Don't use device name generated by the rtnetlink layer when ifname 1346 * isn't specified. Let ppp_dev_configure() set the device name using 1347 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows 1348 * userspace to infer the device name using to the PPPIOCGUNIT ioctl. 1349 */ 1350 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME])) 1351 conf.ifname_is_set = false; 1352 1353 err = ppp_dev_configure(link_net, dev, &conf); 1354 1355 out_unlock: 1356 mutex_unlock(&ppp_mutex); 1357 out: 1358 fput(file); 1359 1360 return err; 1361 } 1362 1363 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head) 1364 { 1365 unregister_netdevice_queue(dev, head); 1366 } 1367 1368 static size_t ppp_nl_get_size(const struct net_device *dev) 1369 { 1370 return 0; 1371 } 1372 1373 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev) 1374 { 1375 return 0; 1376 } 1377 1378 static struct net *ppp_nl_get_link_net(const struct net_device *dev) 1379 { 1380 struct ppp *ppp = netdev_priv(dev); 1381 1382 return READ_ONCE(ppp->ppp_net); 1383 } 1384 1385 static struct rtnl_link_ops ppp_link_ops __read_mostly = { 1386 .kind = "ppp", 1387 .maxtype = IFLA_PPP_MAX, 1388 .policy = ppp_nl_policy, 1389 .priv_size = sizeof(struct ppp), 1390 .setup = ppp_setup, 1391 .validate = ppp_nl_validate, 1392 .newlink = ppp_nl_newlink, 1393 .dellink = ppp_nl_dellink, 1394 .get_size = ppp_nl_get_size, 1395 .fill_info = ppp_nl_fill_info, 1396 .get_link_net = ppp_nl_get_link_net, 1397 }; 1398 1399 #define PPP_MAJOR 108 1400 1401 /* Called at boot time if ppp is compiled into the kernel, 1402 or at module load time (from init_module) if compiled as a module. */ 1403 static int __init ppp_init(void) 1404 { 1405 int err; 1406 1407 pr_info("PPP generic driver version " PPP_VERSION "\n"); 1408 1409 err = register_pernet_device(&ppp_net_ops); 1410 if (err) { 1411 pr_err("failed to register PPP pernet device (%d)\n", err); 1412 goto out; 1413 } 1414 1415 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops); 1416 if (err) { 1417 pr_err("failed to register PPP device (%d)\n", err); 1418 goto out_net; 1419 } 1420 1421 err = class_register(&ppp_class); 1422 if (err) 1423 goto out_chrdev; 1424 1425 err = rtnl_link_register(&ppp_link_ops); 1426 if (err) { 1427 pr_err("failed to register rtnetlink PPP handler\n"); 1428 goto out_class; 1429 } 1430 1431 /* not a big deal if we fail here :-) */ 1432 device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp"); 1433 1434 return 0; 1435 1436 out_class: 1437 class_unregister(&ppp_class); 1438 out_chrdev: 1439 unregister_chrdev(PPP_MAJOR, "ppp"); 1440 out_net: 1441 unregister_pernet_device(&ppp_net_ops); 1442 out: 1443 return err; 1444 } 1445 1446 /* 1447 * Network interface unit routines. 1448 */ 1449 static netdev_tx_t 1450 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev) 1451 { 1452 struct ppp *ppp = netdev_priv(dev); 1453 int npi, proto; 1454 unsigned char *pp; 1455 1456 npi = ethertype_to_npindex(ntohs(skb->protocol)); 1457 if (npi < 0) 1458 goto outf; 1459 1460 /* Drop, accept or reject the packet */ 1461 switch (READ_ONCE(ppp->npmode[npi])) { 1462 case NPMODE_PASS: 1463 break; 1464 case NPMODE_QUEUE: 1465 /* it would be nice to have a way to tell the network 1466 system to queue this one up for later. */ 1467 goto outf; 1468 case NPMODE_DROP: 1469 case NPMODE_ERROR: 1470 goto outf; 1471 } 1472 1473 /* Put the 2-byte PPP protocol number on the front, 1474 making sure there is room for the address and control fields. */ 1475 if (skb_cow_head(skb, PPP_HDRLEN)) 1476 goto outf; 1477 1478 pp = skb_push(skb, 2); 1479 proto = npindex_to_proto[npi]; 1480 put_unaligned_be16(proto, pp); 1481 1482 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev))); 1483 ppp_xmit_process(ppp, skb); 1484 1485 return NETDEV_TX_OK; 1486 1487 outf: 1488 kfree_skb(skb); 1489 DEV_STATS_INC(dev, tx_dropped); 1490 return NETDEV_TX_OK; 1491 } 1492 1493 static int 1494 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr, 1495 void __user *addr, int cmd) 1496 { 1497 struct ppp *ppp = netdev_priv(dev); 1498 int err = -EFAULT; 1499 struct ppp_stats stats; 1500 struct ppp_comp_stats cstats; 1501 char *vers; 1502 1503 switch (cmd) { 1504 case SIOCGPPPSTATS: 1505 ppp_get_stats(ppp, &stats); 1506 if (copy_to_user(addr, &stats, sizeof(stats))) 1507 break; 1508 err = 0; 1509 break; 1510 1511 case SIOCGPPPCSTATS: 1512 memset(&cstats, 0, sizeof(cstats)); 1513 if (ppp->xc_state) 1514 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c); 1515 if (ppp->rc_state) 1516 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d); 1517 if (copy_to_user(addr, &cstats, sizeof(cstats))) 1518 break; 1519 err = 0; 1520 break; 1521 1522 case SIOCGPPPVER: 1523 vers = PPP_VERSION; 1524 if (copy_to_user(addr, vers, strlen(vers) + 1)) 1525 break; 1526 err = 0; 1527 break; 1528 1529 default: 1530 err = -EINVAL; 1531 } 1532 1533 return err; 1534 } 1535 1536 static void 1537 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64) 1538 { 1539 stats64->rx_errors = DEV_STATS_READ(dev, rx_errors); 1540 stats64->tx_errors = DEV_STATS_READ(dev, tx_errors); 1541 stats64->rx_dropped = DEV_STATS_READ(dev, rx_dropped); 1542 stats64->tx_dropped = DEV_STATS_READ(dev, tx_dropped); 1543 stats64->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors); 1544 dev_fetch_sw_netstats(stats64, dev->tstats); 1545 } 1546 1547 static int ppp_dev_init(struct net_device *dev) 1548 { 1549 struct ppp *ppp; 1550 1551 netdev_lockdep_set_classes(dev); 1552 1553 ppp = netdev_priv(dev); 1554 /* Let the netdevice take a reference on the ppp file. This ensures 1555 * that ppp_destroy_interface() won't run before the device gets 1556 * unregistered. 1557 */ 1558 refcount_inc(&ppp->file.refcnt); 1559 1560 return 0; 1561 } 1562 1563 static void ppp_dev_uninit(struct net_device *dev) 1564 { 1565 struct ppp *ppp = netdev_priv(dev); 1566 struct ppp_net *pn = ppp_pernet(ppp->ppp_net); 1567 1568 ppp_lock(ppp); 1569 ppp->closing = 1; 1570 ppp_unlock(ppp); 1571 1572 mutex_lock(&pn->all_ppp_mutex); 1573 unit_put(&pn->units_idr, ppp->file.index); 1574 mutex_unlock(&pn->all_ppp_mutex); 1575 1576 ppp->owner = NULL; 1577 1578 ppp->file.dead = 1; 1579 wake_up_interruptible(&ppp->file.rwait); 1580 } 1581 1582 static void ppp_dev_priv_destructor(struct net_device *dev) 1583 { 1584 struct ppp *ppp; 1585 1586 ppp = netdev_priv(dev); 1587 ppp_release_interface(ppp); 1588 } 1589 1590 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx, 1591 struct net_device_path *path) 1592 { 1593 struct ppp *ppp = netdev_priv(ctx->dev); 1594 struct ppp_channel *chan; 1595 struct channel *pch; 1596 1597 if (ppp->flags & SC_MULTILINK) 1598 return -EOPNOTSUPP; 1599 1600 pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist); 1601 if (!pch) 1602 return -ENODEV; 1603 1604 chan = pch->chan; 1605 if (!chan->ops->fill_forward_path) 1606 return -EOPNOTSUPP; 1607 1608 return chan->ops->fill_forward_path(ctx, path, chan); 1609 } 1610 1611 static const struct net_device_ops ppp_netdev_ops = { 1612 .ndo_init = ppp_dev_init, 1613 .ndo_uninit = ppp_dev_uninit, 1614 .ndo_start_xmit = ppp_start_xmit, 1615 .ndo_siocdevprivate = ppp_net_siocdevprivate, 1616 .ndo_get_stats64 = ppp_get_stats64, 1617 .ndo_fill_forward_path = ppp_fill_forward_path, 1618 }; 1619 1620 static const struct device_type ppp_type = { 1621 .name = "ppp", 1622 }; 1623 1624 static void ppp_setup(struct net_device *dev) 1625 { 1626 dev->netdev_ops = &ppp_netdev_ops; 1627 SET_NETDEV_DEVTYPE(dev, &ppp_type); 1628 1629 dev->lltx = true; 1630 1631 dev->hard_header_len = PPP_HDRLEN; 1632 dev->mtu = PPP_MRU; 1633 dev->addr_len = 0; 1634 dev->tx_queue_len = 3; 1635 dev->type = ARPHRD_PPP; 1636 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 1637 dev->priv_destructor = ppp_dev_priv_destructor; 1638 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS; 1639 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST; 1640 dev->hw_features = dev->features; 1641 netif_keep_dst(dev); 1642 } 1643 1644 /* 1645 * Transmit-side routines. 1646 */ 1647 1648 /* Called to do any work queued up on the transmit side that can now be done */ 1649 static void ppp_xmit_flush(struct ppp *ppp) 1650 { 1651 struct sk_buff *skb; 1652 1653 while ((skb = skb_dequeue(&ppp->file.xq))) { 1654 if (unlikely(!ppp_push(ppp, skb))) { 1655 skb_queue_head(&ppp->file.xq, skb); 1656 return; 1657 } 1658 } 1659 /* If there's no work left to do, tell the core net code that we can 1660 * accept some more. 1661 */ 1662 netif_wake_queue(ppp->dev); 1663 } 1664 1665 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1666 { 1667 ppp_xmit_lock(ppp); 1668 if (unlikely(ppp->closing)) { 1669 kfree_skb(skb); 1670 goto out; 1671 } 1672 if (unlikely(ppp_prepare_tx_skb(ppp, &skb))) 1673 goto out; 1674 /* Fastpath: No backlog, just send the new skb. */ 1675 if (likely(skb_queue_empty(&ppp->file.xq))) { 1676 if (unlikely(!ppp_push(ppp, skb))) { 1677 skb_queue_tail(&ppp->file.xq, skb); 1678 netif_stop_queue(ppp->dev); 1679 } 1680 goto out; 1681 } 1682 1683 /* Slowpath: Enqueue the new skb and process backlog */ 1684 skb_queue_tail(&ppp->file.xq, skb); 1685 ppp_xmit_flush(ppp); 1686 out: 1687 ppp_xmit_unlock(ppp); 1688 } 1689 1690 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1691 { 1692 struct ppp_xmit_recursion *xmit_recursion; 1693 1694 local_bh_disable(); 1695 1696 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion); 1697 if (xmit_recursion->owner == current) 1698 goto err; 1699 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock); 1700 xmit_recursion->owner = current; 1701 1702 __ppp_xmit_process(ppp, skb); 1703 1704 xmit_recursion->owner = NULL; 1705 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock); 1706 local_bh_enable(); 1707 1708 return; 1709 1710 err: 1711 local_bh_enable(); 1712 1713 kfree_skb(skb); 1714 1715 if (net_ratelimit()) 1716 netdev_err(ppp->dev, "recursion detected\n"); 1717 } 1718 1719 static inline struct sk_buff * 1720 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) 1721 { 1722 struct sk_buff *new_skb; 1723 int len; 1724 int new_skb_size = ppp->dev->mtu + 1725 ppp->xcomp->comp_extra + ppp->dev->hard_header_len; 1726 int compressor_skb_size = ppp->dev->mtu + 1727 ppp->xcomp->comp_extra + PPP_HDRLEN; 1728 1729 if (skb_linearize(skb)) 1730 return NULL; 1731 1732 new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); 1733 if (!new_skb) { 1734 if (net_ratelimit()) 1735 netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n"); 1736 return NULL; 1737 } 1738 if (ppp->dev->hard_header_len > PPP_HDRLEN) 1739 skb_reserve(new_skb, 1740 ppp->dev->hard_header_len - PPP_HDRLEN); 1741 1742 /* compressor still expects A/C bytes in hdr */ 1743 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, 1744 new_skb->data, skb->len + 2, 1745 compressor_skb_size); 1746 if (len > 0 && (ppp->flags & SC_CCP_UP)) { 1747 consume_skb(skb); 1748 skb = new_skb; 1749 skb_put(skb, len); 1750 skb_pull(skb, 2); /* pull off A/C bytes */ 1751 } else if (len == 0) { 1752 /* didn't compress, or CCP not up yet */ 1753 consume_skb(new_skb); 1754 new_skb = skb; 1755 } else { 1756 /* 1757 * (len < 0) 1758 * MPPE requires that we do not send unencrypted 1759 * frames. The compressor will return -1 if we 1760 * should drop the frame. We cannot simply test 1761 * the compress_proto because MPPE and MPPC share 1762 * the same number. 1763 */ 1764 if (net_ratelimit()) 1765 netdev_err(ppp->dev, "ppp: compressor dropped pkt\n"); 1766 consume_skb(new_skb); 1767 new_skb = NULL; 1768 } 1769 return new_skb; 1770 } 1771 1772 /* 1773 * Compress and prepare to send a frame. 1774 * The caller should have locked the xmit path. 1775 * Returns 1 if the skb was consumed, 0 if it can be passed to ppp_push(). 1776 * @pskb is updated if a compressor is in use. 1777 */ 1778 static int 1779 ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb) 1780 { 1781 struct sk_buff *skb = *pskb; 1782 int proto = PPP_PROTO(skb); 1783 struct sk_buff *new_skb; 1784 int len; 1785 unsigned char *cp; 1786 1787 skb->dev = ppp->dev; 1788 1789 if (proto < 0x8000) { 1790 #ifdef CONFIG_PPP_FILTER 1791 /* check if the packet passes the pass and active filters. 1792 * See comment for PPP_FILTER_OUTBOUND_TAG above. 1793 */ 1794 *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_OUTBOUND_TAG); 1795 if (ppp->pass_filter && 1796 bpf_prog_run(ppp->pass_filter, skb) == 0) { 1797 if (READ_ONCE(ppp->debug) & 1) 1798 netdev_printk(KERN_DEBUG, ppp->dev, 1799 "PPP: outbound frame " 1800 "not passed\n"); 1801 kfree_skb(skb); 1802 return 1; 1803 } 1804 /* if this packet passes the active filter, record the time */ 1805 if (!(ppp->active_filter && 1806 bpf_prog_run(ppp->active_filter, skb) == 0)) 1807 WRITE_ONCE(ppp->last_xmit, jiffies); 1808 skb_pull(skb, 2); 1809 #else 1810 /* for data packets, record the time */ 1811 WRITE_ONCE(ppp->last_xmit, jiffies); 1812 #endif /* CONFIG_PPP_FILTER */ 1813 } 1814 1815 dev_sw_netstats_tx_add(ppp->dev, 1, skb->len - PPP_PROTO_LEN); 1816 1817 switch (proto) { 1818 case PPP_IP: 1819 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0) 1820 break; 1821 1822 if (skb_linearize(skb)) 1823 goto drop; 1824 1825 /* try to do VJ TCP header compression */ 1826 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2, 1827 GFP_ATOMIC); 1828 if (!new_skb) { 1829 netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n"); 1830 goto drop; 1831 } 1832 skb_reserve(new_skb, ppp->dev->hard_header_len - 2); 1833 cp = skb->data + 2; 1834 len = slhc_compress(ppp->vj, cp, skb->len - 2, 1835 new_skb->data + 2, &cp, 1836 !(ppp->flags & SC_NO_TCP_CCID)); 1837 if (cp == skb->data + 2) { 1838 /* didn't compress */ 1839 consume_skb(new_skb); 1840 } else { 1841 if (cp[0] & SL_TYPE_COMPRESSED_TCP) { 1842 proto = PPP_VJC_COMP; 1843 cp[0] &= ~SL_TYPE_COMPRESSED_TCP; 1844 } else { 1845 proto = PPP_VJC_UNCOMP; 1846 cp[0] = skb->data[2]; 1847 } 1848 consume_skb(skb); 1849 skb = new_skb; 1850 *pskb = skb; 1851 cp = skb_put(skb, len + 2); 1852 cp[0] = 0; 1853 cp[1] = proto; 1854 } 1855 break; 1856 1857 case PPP_CCP: 1858 /* peek at outbound CCP frames */ 1859 ppp_ccp_peek(ppp, skb, 0); 1860 break; 1861 } 1862 1863 /* try to do packet compression */ 1864 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state && 1865 proto != PPP_LCP && proto != PPP_CCP) { 1866 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) { 1867 if (net_ratelimit()) 1868 netdev_err(ppp->dev, 1869 "ppp: compression required but " 1870 "down - pkt dropped.\n"); 1871 goto drop; 1872 } 1873 new_skb = pad_compress_skb(ppp, skb); 1874 if (!new_skb) 1875 goto drop; 1876 skb = new_skb; 1877 *pskb = skb; 1878 } 1879 1880 /* 1881 * If we are waiting for traffic (demand dialling), 1882 * queue it up for pppd to receive. 1883 */ 1884 if (ppp->flags & SC_LOOP_TRAFFIC) { 1885 if (ppp->file.rq.qlen > PPP_MAX_RQLEN) 1886 goto drop; 1887 skb_queue_tail(&ppp->file.rq, skb); 1888 wake_up_interruptible(&ppp->file.rwait); 1889 return 1; 1890 } 1891 1892 return 0; 1893 1894 drop: 1895 kfree_skb(skb); 1896 DEV_STATS_INC(ppp->dev, tx_errors); 1897 return 1; 1898 } 1899 1900 /* 1901 * Try to send the frame. 1902 * The caller should have the xmit path locked. 1903 * Returns 1 if the skb was consumed, 0 if not. 1904 */ 1905 static int 1906 ppp_push(struct ppp *ppp, struct sk_buff *skb) 1907 { 1908 struct list_head *list; 1909 struct channel *pch; 1910 1911 list = &ppp->channels; 1912 if (list_empty(list)) { 1913 /* nowhere to send the packet, just drop it */ 1914 kfree_skb(skb); 1915 return 1; 1916 } 1917 1918 if ((ppp->flags & SC_MULTILINK) == 0) { 1919 struct ppp_channel *chan; 1920 int ret; 1921 /* not doing multilink: send it down the first channel */ 1922 list = list->next; 1923 pch = list_entry(list, struct channel, clist); 1924 1925 spin_lock(&pch->downl); 1926 chan = pch->chan; 1927 if (unlikely(!chan->direct_xmit && skb_linearize(skb))) { 1928 /* channel requires a linear skb but linearization 1929 * failed 1930 */ 1931 kfree_skb(skb); 1932 ret = 1; 1933 goto out; 1934 } 1935 1936 ret = chan->ops->start_xmit(chan, skb); 1937 1938 out: 1939 spin_unlock(&pch->downl); 1940 return ret; 1941 } 1942 1943 #ifdef CONFIG_PPP_MULTILINK 1944 /* Multilink: fragment the packet over as many links 1945 as can take the packet at the moment. */ 1946 if (!ppp_mp_explode(ppp, skb)) 1947 return 0; 1948 #endif /* CONFIG_PPP_MULTILINK */ 1949 1950 kfree_skb(skb); 1951 return 1; 1952 } 1953 1954 #ifdef CONFIG_PPP_MULTILINK 1955 static bool mp_protocol_compress __read_mostly = true; 1956 module_param(mp_protocol_compress, bool, 0644); 1957 MODULE_PARM_DESC(mp_protocol_compress, 1958 "compress protocol id in multilink fragments"); 1959 1960 /* 1961 * Divide a packet to be transmitted into fragments and 1962 * send them out the individual links. 1963 */ 1964 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb) 1965 { 1966 int len, totlen; 1967 int i, bits, hdrlen, mtu; 1968 int flen; 1969 int navail, nfree, nzero; 1970 int nbigger; 1971 int totspeed; 1972 int totfree; 1973 unsigned char *p, *q; 1974 struct list_head *list; 1975 struct channel *pch; 1976 struct sk_buff *frag; 1977 struct ppp_channel *chan; 1978 1979 totspeed = 0; /*total bitrate of the bundle*/ 1980 nfree = 0; /* # channels which have no packet already queued */ 1981 navail = 0; /* total # of usable channels (not deregistered) */ 1982 nzero = 0; /* number of channels with zero speed associated*/ 1983 totfree = 0; /*total # of channels available and 1984 *having no queued packets before 1985 *starting the fragmentation*/ 1986 1987 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 1988 i = 0; 1989 list_for_each_entry(pch, &ppp->channels, clist) { 1990 pch->avail = 1; 1991 navail++; 1992 pch->speed = pch->chan->speed; 1993 1994 if (skb_queue_empty(&pch->file.xq) || !pch->had_frag) { 1995 if (pch->speed == 0) 1996 nzero++; 1997 else 1998 totspeed += pch->speed; 1999 2000 pch->avail = 2; 2001 ++nfree; 2002 ++totfree; 2003 } 2004 if (!pch->had_frag && i < ppp->nxchan) 2005 ppp->nxchan = i; 2006 2007 ++i; 2008 } 2009 /* 2010 * Don't start sending this packet unless at least half of 2011 * the channels are free. This gives much better TCP 2012 * performance if we have a lot of channels. 2013 */ 2014 if (nfree == 0 || nfree < navail / 2) 2015 return 0; /* can't take now, leave it in transmit queue */ 2016 2017 /* Do protocol field compression */ 2018 if (skb_linearize(skb)) 2019 goto err_linearize; 2020 p = skb->data; 2021 len = skb->len; 2022 if (*p == 0 && mp_protocol_compress) { 2023 ++p; 2024 --len; 2025 } 2026 2027 totlen = len; 2028 nbigger = len % nfree; 2029 2030 /* skip to the channel after the one we last used 2031 and start at that one */ 2032 list = &ppp->channels; 2033 for (i = 0; i < ppp->nxchan; ++i) { 2034 list = list->next; 2035 if (list == &ppp->channels) { 2036 i = 0; 2037 break; 2038 } 2039 } 2040 2041 /* create a fragment for each channel */ 2042 bits = B; 2043 while (len > 0) { 2044 list = list->next; 2045 if (list == &ppp->channels) { 2046 i = 0; 2047 continue; 2048 } 2049 pch = list_entry(list, struct channel, clist); 2050 ++i; 2051 if (!pch->avail) 2052 continue; 2053 2054 /* 2055 * Skip this channel if it has a fragment pending already and 2056 * we haven't given a fragment to all of the free channels. 2057 */ 2058 if (pch->avail == 1) { 2059 if (nfree > 0) 2060 continue; 2061 } else { 2062 pch->avail = 1; 2063 } 2064 2065 spin_lock(&pch->downl); 2066 /* 2067 *if the channel speed is not set divide 2068 *the packet evenly among the free channels; 2069 *otherwise divide it according to the speed 2070 *of the channel we are going to transmit on 2071 */ 2072 flen = len; 2073 if (nfree > 0) { 2074 if (pch->speed == 0) { 2075 flen = len/nfree; 2076 if (nbigger > 0) { 2077 flen++; 2078 nbigger--; 2079 } 2080 } else { 2081 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) / 2082 ((totspeed*totfree)/pch->speed)) - hdrlen; 2083 if (nbigger > 0) { 2084 flen += ((totfree - nzero)*pch->speed)/totspeed; 2085 nbigger -= ((totfree - nzero)*pch->speed)/ 2086 totspeed; 2087 } 2088 } 2089 nfree--; 2090 } 2091 2092 /* 2093 *check if we are on the last channel or 2094 *we exceded the length of the data to 2095 *fragment 2096 */ 2097 if ((nfree <= 0) || (flen > len)) 2098 flen = len; 2099 /* 2100 *it is not worth to tx on slow channels: 2101 *in that case from the resulting flen according to the 2102 *above formula will be equal or less than zero. 2103 *Skip the channel in this case 2104 */ 2105 if (flen <= 0) { 2106 pch->avail = 2; 2107 spin_unlock(&pch->downl); 2108 continue; 2109 } 2110 2111 /* 2112 * hdrlen includes the 2-byte PPP protocol field, but the 2113 * MTU counts only the payload excluding the protocol field. 2114 * (RFC1661 Section 2) 2115 */ 2116 mtu = pch->chan->mtu - (hdrlen - 2); 2117 if (mtu < 4) 2118 mtu = 4; 2119 if (flen > mtu) 2120 flen = mtu; 2121 if (flen == len) 2122 bits |= E; 2123 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC); 2124 if (!frag) 2125 goto noskb; 2126 q = skb_put(frag, flen + hdrlen); 2127 2128 /* make the MP header */ 2129 put_unaligned_be16(PPP_MP, q); 2130 if (ppp->flags & SC_MP_XSHORTSEQ) { 2131 q[2] = bits + ((ppp->nxseq >> 8) & 0xf); 2132 q[3] = ppp->nxseq; 2133 } else { 2134 q[2] = bits; 2135 q[3] = ppp->nxseq >> 16; 2136 q[4] = ppp->nxseq >> 8; 2137 q[5] = ppp->nxseq; 2138 } 2139 2140 memcpy(q + hdrlen, p, flen); 2141 2142 /* try to send it down the channel */ 2143 chan = pch->chan; 2144 if (!skb_queue_empty(&pch->file.xq) || 2145 !chan->ops->start_xmit(chan, frag)) 2146 skb_queue_tail(&pch->file.xq, frag); 2147 pch->had_frag = 1; 2148 p += flen; 2149 len -= flen; 2150 ++ppp->nxseq; 2151 bits = 0; 2152 spin_unlock(&pch->downl); 2153 } 2154 ppp->nxchan = i; 2155 2156 return 1; 2157 2158 noskb: 2159 spin_unlock(&pch->downl); 2160 err_linearize: 2161 if (READ_ONCE(ppp->debug) & 1) 2162 netdev_err(ppp->dev, "PPP: no memory (fragment)\n"); 2163 DEV_STATS_INC(ppp->dev, tx_errors); 2164 ++ppp->nxseq; 2165 return 1; /* abandon the frame */ 2166 } 2167 #endif /* CONFIG_PPP_MULTILINK */ 2168 2169 /* Try to send data out on a channel */ 2170 static void __ppp_channel_push(struct channel *pch, struct ppp *ppp) 2171 { 2172 struct sk_buff *skb; 2173 2174 spin_lock(&pch->downl); 2175 if (pch->chan) { 2176 while (!skb_queue_empty(&pch->file.xq)) { 2177 skb = skb_dequeue(&pch->file.xq); 2178 if (!pch->chan->ops->start_xmit(pch->chan, skb)) { 2179 /* put the packet back and try again later */ 2180 skb_queue_head(&pch->file.xq, skb); 2181 break; 2182 } 2183 } 2184 } else { 2185 /* channel got deregistered */ 2186 skb_queue_purge(&pch->file.xq); 2187 } 2188 spin_unlock(&pch->downl); 2189 /* see if there is anything from the attached unit to be sent */ 2190 if (skb_queue_empty(&pch->file.xq)) { 2191 if (ppp) { 2192 ppp_xmit_lock(ppp); 2193 if (!ppp->closing) 2194 ppp_xmit_flush(ppp); 2195 ppp_xmit_unlock(ppp); 2196 } 2197 } 2198 } 2199 2200 static void ppp_channel_push(struct channel *pch) 2201 { 2202 struct ppp_xmit_recursion *xmit_recursion; 2203 struct ppp *ppp; 2204 2205 rcu_read_lock_bh(); 2206 ppp = rcu_dereference_bh(pch->ppp); 2207 if (ppp) { 2208 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion); 2209 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock); 2210 xmit_recursion->owner = current; 2211 __ppp_channel_push(pch, ppp); 2212 xmit_recursion->owner = NULL; 2213 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock); 2214 } else { 2215 __ppp_channel_push(pch, NULL); 2216 } 2217 rcu_read_unlock_bh(); 2218 } 2219 2220 /* 2221 * Receive-side routines. 2222 */ 2223 2224 struct ppp_mp_skb_parm { 2225 u32 sequence; 2226 u8 BEbits; 2227 }; 2228 #define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb)) 2229 2230 static inline void 2231 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2232 { 2233 ppp_recv_lock(ppp); 2234 if (!ppp->closing) 2235 ppp_receive_frame(ppp, skb, pch); 2236 else 2237 kfree_skb(skb); 2238 ppp_recv_unlock(ppp); 2239 } 2240 2241 /** 2242 * __ppp_decompress_proto - Decompress protocol field, slim version. 2243 * @skb: Socket buffer where protocol field should be decompressed. It must have 2244 * at least 1 byte of head room and 1 byte of linear data. First byte of 2245 * data must be a protocol field byte. 2246 * 2247 * Decompress protocol field in PPP header if it's compressed, e.g. when 2248 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data 2249 * length are done in this function. 2250 */ 2251 static void __ppp_decompress_proto(struct sk_buff *skb) 2252 { 2253 if (ppp_skb_is_compressed_proto(skb)) 2254 *(u8 *)skb_push(skb, 1) = 0x00; 2255 } 2256 2257 /** 2258 * ppp_decompress_proto - Check skb data room and decompress protocol field. 2259 * @skb: Socket buffer where protocol field should be decompressed. First byte 2260 * of data must be a protocol field byte. 2261 * 2262 * Decompress protocol field in PPP header if it's compressed, e.g. when 2263 * Protocol-Field-Compression (PFC) was negotiated. This function also makes 2264 * sure that skb data room is sufficient for Protocol field, before and after 2265 * decompression. 2266 * 2267 * Return: true - decompressed successfully, false - not enough room in skb. 2268 */ 2269 static bool ppp_decompress_proto(struct sk_buff *skb) 2270 { 2271 /* At least one byte should be present (if protocol is compressed) */ 2272 if (!pskb_may_pull(skb, 1)) 2273 return false; 2274 2275 __ppp_decompress_proto(skb); 2276 2277 /* Protocol field should occupy 2 bytes when not compressed */ 2278 return pskb_may_pull(skb, 2); 2279 } 2280 2281 /* Attempt to handle a frame via. a bridged channel, if one exists. 2282 * If the channel is bridged, the frame is consumed by the bridge. 2283 * If not, the caller must handle the frame by normal recv mechanisms. 2284 * Returns true if the frame is consumed, false otherwise. 2285 */ 2286 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb) 2287 { 2288 struct channel *pchb; 2289 2290 rcu_read_lock(); 2291 pchb = rcu_dereference(pch->bridge); 2292 if (!pchb) 2293 goto out_rcu; 2294 2295 spin_lock_bh(&pchb->downl); 2296 if (!pchb->chan) { 2297 /* channel got unregistered */ 2298 kfree_skb(skb); 2299 goto outl; 2300 } 2301 2302 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net)); 2303 if (!pchb->chan->ops->start_xmit(pchb->chan, skb)) 2304 kfree_skb(skb); 2305 2306 outl: 2307 spin_unlock_bh(&pchb->downl); 2308 out_rcu: 2309 rcu_read_unlock(); 2310 2311 /* If pchb is set then we've consumed the packet */ 2312 return !!pchb; 2313 } 2314 2315 void 2316 ppp_input(struct ppp_channel *chan, struct sk_buff *skb) 2317 { 2318 struct channel *pch = chan->ppp; 2319 struct ppp *ppp; 2320 int proto; 2321 2322 if (!pch) { 2323 kfree_skb(skb); 2324 return; 2325 } 2326 2327 /* If the channel is bridged, transmit via. bridge */ 2328 if (ppp_channel_bridge_input(pch, skb)) 2329 return; 2330 2331 rcu_read_lock_bh(); 2332 ppp = rcu_dereference_bh(pch->ppp); 2333 if (!ppp_decompress_proto(skb)) { 2334 kfree_skb(skb); 2335 if (ppp) { 2336 DEV_STATS_INC(ppp->dev, rx_length_errors); 2337 ppp_receive_error(ppp); 2338 } 2339 goto done; 2340 } 2341 2342 proto = PPP_PROTO(skb); 2343 if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) { 2344 /* put it on the channel queue */ 2345 skb_queue_tail(&pch->file.rq, skb); 2346 /* drop old frames if queue too long */ 2347 while (pch->file.rq.qlen > PPP_MAX_RQLEN && 2348 (skb = skb_dequeue(&pch->file.rq))) 2349 kfree_skb(skb); 2350 wake_up_interruptible(&pch->file.rwait); 2351 } else { 2352 ppp_do_recv(ppp, skb, pch); 2353 } 2354 2355 done: 2356 rcu_read_unlock_bh(); 2357 } 2358 2359 void 2360 ppp_input_error(struct ppp_channel *chan) 2361 { 2362 struct channel *pch = chan->ppp; 2363 struct ppp *ppp; 2364 2365 if (!pch) 2366 return; 2367 2368 rcu_read_lock_bh(); 2369 ppp = rcu_dereference_bh(pch->ppp); 2370 if (ppp) { 2371 ppp_recv_lock(ppp); 2372 ppp_receive_error(ppp); 2373 ppp_recv_unlock(ppp); 2374 } 2375 rcu_read_unlock_bh(); 2376 } 2377 2378 /* 2379 * We come in here to process a received frame. 2380 * The receive side of the ppp unit is locked. 2381 */ 2382 static void 2383 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2384 { 2385 skb_checksum_complete_unset(skb); 2386 #ifdef CONFIG_PPP_MULTILINK 2387 /* XXX do channel-level decompression here */ 2388 if (PPP_PROTO(skb) == PPP_MP) 2389 ppp_receive_mp_frame(ppp, skb, pch); 2390 else 2391 #endif /* CONFIG_PPP_MULTILINK */ 2392 ppp_receive_nonmp_frame(ppp, skb); 2393 } 2394 2395 static void 2396 ppp_receive_error(struct ppp *ppp) 2397 { 2398 DEV_STATS_INC(ppp->dev, rx_errors); 2399 if (ppp->vj) 2400 slhc_toss(ppp->vj); 2401 } 2402 2403 static void 2404 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb) 2405 { 2406 struct sk_buff *ns; 2407 int proto, len, npi; 2408 2409 /* 2410 * Decompress the frame, if compressed. 2411 * Note that some decompressors need to see uncompressed frames 2412 * that come in as well as compressed frames. 2413 */ 2414 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) && 2415 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0) 2416 skb = ppp_decompress_frame(ppp, skb); 2417 2418 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR) 2419 goto err; 2420 2421 /* At this point the "Protocol" field MUST be decompressed, either in 2422 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame(). 2423 */ 2424 proto = PPP_PROTO(skb); 2425 switch (proto) { 2426 case PPP_VJC_COMP: 2427 /* decompress VJ compressed packets */ 2428 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2429 goto err; 2430 2431 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) { 2432 /* copy to a new sk_buff with more tailroom */ 2433 ns = dev_alloc_skb(skb->len + 128); 2434 if (!ns) { 2435 netdev_err(ppp->dev, "PPP: no memory " 2436 "(VJ decomp)\n"); 2437 goto err; 2438 } 2439 skb_reserve(ns, 2); 2440 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); 2441 consume_skb(skb); 2442 skb = ns; 2443 } 2444 else 2445 skb->ip_summed = CHECKSUM_NONE; 2446 2447 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2); 2448 if (len <= 0) { 2449 netdev_printk(KERN_DEBUG, ppp->dev, 2450 "PPP: VJ decompression error\n"); 2451 goto err; 2452 } 2453 len += 2; 2454 if (len > skb->len) 2455 skb_put(skb, len - skb->len); 2456 else if (len < skb->len) 2457 skb_trim(skb, len); 2458 proto = PPP_IP; 2459 break; 2460 2461 case PPP_VJC_UNCOMP: 2462 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2463 goto err; 2464 2465 /* Until we fix the decompressor need to make sure 2466 * data portion is linear. 2467 */ 2468 if (!pskb_may_pull(skb, skb->len)) 2469 goto err; 2470 2471 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) { 2472 netdev_err(ppp->dev, "PPP: VJ uncompressed error\n"); 2473 goto err; 2474 } 2475 proto = PPP_IP; 2476 break; 2477 2478 case PPP_CCP: 2479 ppp_ccp_peek(ppp, skb, 1); 2480 break; 2481 } 2482 2483 dev_sw_netstats_rx_add(ppp->dev, skb->len - PPP_PROTO_LEN); 2484 2485 npi = proto_to_npindex(proto); 2486 if (npi < 0) { 2487 /* control or unknown frame - pass it to pppd */ 2488 skb_queue_tail(&ppp->file.rq, skb); 2489 /* limit queue length by dropping old frames */ 2490 while (ppp->file.rq.qlen > PPP_MAX_RQLEN && 2491 (skb = skb_dequeue(&ppp->file.rq))) 2492 kfree_skb(skb); 2493 /* wake up any process polling or blocking on read */ 2494 wake_up_interruptible(&ppp->file.rwait); 2495 2496 } else { 2497 /* network protocol frame - give it to the kernel */ 2498 2499 #ifdef CONFIG_PPP_FILTER 2500 if (ppp->pass_filter || ppp->active_filter) { 2501 if (skb_unclone(skb, GFP_ATOMIC)) 2502 goto err; 2503 /* Check if the packet passes the pass and active filters. 2504 * See comment for PPP_FILTER_INBOUND_TAG above. 2505 */ 2506 *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG); 2507 if (ppp->pass_filter && 2508 bpf_prog_run(ppp->pass_filter, skb) == 0) { 2509 if (READ_ONCE(ppp->debug) & 1) 2510 netdev_printk(KERN_DEBUG, ppp->dev, 2511 "PPP: inbound frame " 2512 "not passed\n"); 2513 kfree_skb(skb); 2514 return; 2515 } 2516 if (!(ppp->active_filter && 2517 bpf_prog_run(ppp->active_filter, skb) == 0)) 2518 WRITE_ONCE(ppp->last_recv, jiffies); 2519 __skb_pull(skb, 2); 2520 } else 2521 #endif /* CONFIG_PPP_FILTER */ 2522 WRITE_ONCE(ppp->last_recv, jiffies); 2523 2524 if ((ppp->dev->flags & IFF_UP) == 0 || 2525 READ_ONCE(ppp->npmode[npi]) != NPMODE_PASS) { 2526 kfree_skb(skb); 2527 } else { 2528 /* chop off protocol */ 2529 skb_pull_rcsum(skb, 2); 2530 skb->dev = ppp->dev; 2531 skb->protocol = htons(npindex_to_ethertype[npi]); 2532 skb_reset_mac_header(skb); 2533 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, 2534 dev_net(ppp->dev))); 2535 netif_rx(skb); 2536 } 2537 } 2538 return; 2539 2540 err: 2541 kfree_skb(skb); 2542 ppp_receive_error(ppp); 2543 } 2544 2545 static struct sk_buff * 2546 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb) 2547 { 2548 int proto = PPP_PROTO(skb); 2549 struct sk_buff *ns; 2550 int len; 2551 2552 /* Until we fix all the decompressor's need to make sure 2553 * data portion is linear. 2554 */ 2555 if (!pskb_may_pull(skb, skb->len)) 2556 goto err; 2557 2558 if (proto == PPP_COMP) { 2559 int obuff_size; 2560 2561 switch(ppp->rcomp->compress_proto) { 2562 case CI_MPPE: 2563 obuff_size = ppp->mru + PPP_HDRLEN + 1; 2564 break; 2565 default: 2566 obuff_size = ppp->mru + PPP_HDRLEN; 2567 break; 2568 } 2569 2570 ns = dev_alloc_skb(obuff_size); 2571 if (!ns) { 2572 netdev_err(ppp->dev, "ppp_decompress_frame: " 2573 "no memory\n"); 2574 goto err; 2575 } 2576 /* the decompressor still expects the A/C bytes in the hdr */ 2577 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2, 2578 skb->len + 2, ns->data, obuff_size); 2579 if (len < 0) { 2580 /* Pass the compressed frame to pppd as an 2581 error indication. */ 2582 if (len == DECOMP_FATALERROR) 2583 ppp->rstate |= SC_DC_FERROR; 2584 kfree_skb(ns); 2585 goto err; 2586 } 2587 2588 consume_skb(skb); 2589 skb = ns; 2590 skb_put(skb, len); 2591 skb_pull(skb, 2); /* pull off the A/C bytes */ 2592 2593 /* Don't call __ppp_decompress_proto() here, but instead rely on 2594 * corresponding algo (mppe/bsd/deflate) to decompress it. 2595 */ 2596 } else { 2597 /* Uncompressed frame - pass to decompressor so it 2598 can update its dictionary if necessary. */ 2599 if (ppp->rcomp->incomp) 2600 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2, 2601 skb->len + 2); 2602 } 2603 2604 return skb; 2605 2606 err: 2607 ppp->rstate |= SC_DC_ERROR; 2608 ppp_receive_error(ppp); 2609 return skb; 2610 } 2611 2612 #ifdef CONFIG_PPP_MULTILINK 2613 /* 2614 * Receive a multilink frame. 2615 * We put it on the reconstruction queue and then pull off 2616 * as many completed frames as we can. 2617 */ 2618 static void 2619 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2620 { 2621 u32 mask, seq; 2622 struct channel *ch; 2623 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 2624 2625 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0) 2626 goto err; /* no good, throw it away */ 2627 2628 /* Decode sequence number and begin/end bits */ 2629 if (ppp->flags & SC_MP_SHORTSEQ) { 2630 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3]; 2631 mask = 0xfff; 2632 } else { 2633 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5]; 2634 mask = 0xffffff; 2635 } 2636 PPP_MP_CB(skb)->BEbits = skb->data[2]; 2637 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */ 2638 2639 /* 2640 * Do protocol ID decompression on the first fragment of each packet. 2641 * We have to do that here, because ppp_receive_nonmp_frame() expects 2642 * decompressed protocol field. 2643 */ 2644 if (PPP_MP_CB(skb)->BEbits & B) 2645 __ppp_decompress_proto(skb); 2646 2647 /* 2648 * Expand sequence number to 32 bits, making it as close 2649 * as possible to ppp->minseq. 2650 */ 2651 seq |= ppp->minseq & ~mask; 2652 if ((int)(ppp->minseq - seq) > (int)(mask >> 1)) 2653 seq += mask + 1; 2654 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1)) 2655 seq -= mask + 1; /* should never happen */ 2656 PPP_MP_CB(skb)->sequence = seq; 2657 pch->lastseq = seq; 2658 2659 /* 2660 * If this packet comes before the next one we were expecting, 2661 * drop it. 2662 */ 2663 if (seq_before(seq, ppp->nextseq)) { 2664 kfree_skb(skb); 2665 DEV_STATS_INC(ppp->dev, rx_dropped); 2666 ppp_receive_error(ppp); 2667 return; 2668 } 2669 2670 /* 2671 * Reevaluate minseq, the minimum over all channels of the 2672 * last sequence number received on each channel. Because of 2673 * the increasing sequence number rule, we know that any fragment 2674 * before `minseq' which hasn't arrived is never going to arrive. 2675 * The list of channels can't change because we have the receive 2676 * side of the ppp unit locked. 2677 */ 2678 list_for_each_entry(ch, &ppp->channels, clist) { 2679 if (seq_before(ch->lastseq, seq)) 2680 seq = ch->lastseq; 2681 } 2682 if (seq_before(ppp->minseq, seq)) 2683 ppp->minseq = seq; 2684 2685 /* Put the fragment on the reconstruction queue */ 2686 ppp_mp_insert(ppp, skb); 2687 2688 /* If the queue is getting long, don't wait any longer for packets 2689 before the start of the queue. */ 2690 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) { 2691 struct sk_buff *mskb = skb_peek(&ppp->mrq); 2692 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence)) 2693 ppp->minseq = PPP_MP_CB(mskb)->sequence; 2694 } 2695 2696 /* Pull completed packets off the queue and receive them. */ 2697 while ((skb = ppp_mp_reconstruct(ppp))) { 2698 if (pskb_may_pull(skb, 2)) 2699 ppp_receive_nonmp_frame(ppp, skb); 2700 else { 2701 DEV_STATS_INC(ppp->dev, rx_length_errors); 2702 kfree_skb(skb); 2703 ppp_receive_error(ppp); 2704 } 2705 } 2706 2707 return; 2708 2709 err: 2710 kfree_skb(skb); 2711 ppp_receive_error(ppp); 2712 } 2713 2714 /* 2715 * Insert a fragment on the MP reconstruction queue. 2716 * The queue is ordered by increasing sequence number. 2717 */ 2718 static void 2719 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb) 2720 { 2721 struct sk_buff *p; 2722 struct sk_buff_head *list = &ppp->mrq; 2723 u32 seq = PPP_MP_CB(skb)->sequence; 2724 2725 /* N.B. we don't need to lock the list lock because we have the 2726 ppp unit receive-side lock. */ 2727 skb_queue_walk(list, p) { 2728 if (seq_before(seq, PPP_MP_CB(p)->sequence)) 2729 break; 2730 } 2731 __skb_queue_before(list, p, skb); 2732 } 2733 2734 /* 2735 * Reconstruct a packet from the MP fragment queue. 2736 * We go through increasing sequence numbers until we find a 2737 * complete packet, or we get to the sequence number for a fragment 2738 * which hasn't arrived but might still do so. 2739 */ 2740 static struct sk_buff * 2741 ppp_mp_reconstruct(struct ppp *ppp) 2742 { 2743 u32 seq = ppp->nextseq; 2744 u32 minseq = ppp->minseq; 2745 struct sk_buff_head *list = &ppp->mrq; 2746 struct sk_buff *p, *tmp; 2747 struct sk_buff *head, *tail; 2748 struct sk_buff *skb = NULL; 2749 int lost = 0, len = 0; 2750 2751 if (ppp->mrru == 0) /* do nothing until mrru is set */ 2752 return NULL; 2753 head = __skb_peek(list); 2754 tail = NULL; 2755 skb_queue_walk_safe(list, p, tmp) { 2756 again: 2757 if (seq_before(PPP_MP_CB(p)->sequence, seq)) { 2758 /* this can't happen, anyway ignore the skb */ 2759 netdev_err(ppp->dev, "ppp_mp_reconstruct bad " 2760 "seq %u < %u\n", 2761 PPP_MP_CB(p)->sequence, seq); 2762 __skb_unlink(p, list); 2763 kfree_skb(p); 2764 continue; 2765 } 2766 if (PPP_MP_CB(p)->sequence != seq) { 2767 u32 oldseq; 2768 /* Fragment `seq' is missing. If it is after 2769 minseq, it might arrive later, so stop here. */ 2770 if (seq_after(seq, minseq)) 2771 break; 2772 /* Fragment `seq' is lost, keep going. */ 2773 lost = 1; 2774 oldseq = seq; 2775 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)? 2776 minseq + 1: PPP_MP_CB(p)->sequence; 2777 2778 if (READ_ONCE(ppp->debug) & 1) 2779 netdev_printk(KERN_DEBUG, ppp->dev, 2780 "lost frag %u..%u\n", 2781 oldseq, seq-1); 2782 2783 goto again; 2784 } 2785 2786 /* 2787 * At this point we know that all the fragments from 2788 * ppp->nextseq to seq are either present or lost. 2789 * Also, there are no complete packets in the queue 2790 * that have no missing fragments and end before this 2791 * fragment. 2792 */ 2793 2794 /* B bit set indicates this fragment starts a packet */ 2795 if (PPP_MP_CB(p)->BEbits & B) { 2796 head = p; 2797 lost = 0; 2798 len = 0; 2799 } 2800 2801 len += p->len; 2802 2803 /* Got a complete packet yet? */ 2804 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) && 2805 (PPP_MP_CB(head)->BEbits & B)) { 2806 if (len > ppp->mrru + 2) { 2807 DEV_STATS_INC(ppp->dev, rx_length_errors); 2808 netdev_printk(KERN_DEBUG, ppp->dev, 2809 "PPP: reconstructed packet" 2810 " is too long (%d)\n", len); 2811 } else { 2812 tail = p; 2813 break; 2814 } 2815 ppp->nextseq = seq + 1; 2816 } 2817 2818 /* 2819 * If this is the ending fragment of a packet, 2820 * and we haven't found a complete valid packet yet, 2821 * we can discard up to and including this fragment. 2822 */ 2823 if (PPP_MP_CB(p)->BEbits & E) { 2824 struct sk_buff *tmp2; 2825 2826 skb_queue_reverse_walk_from_safe(list, p, tmp2) { 2827 if (READ_ONCE(ppp->debug) & 1) 2828 netdev_printk(KERN_DEBUG, ppp->dev, 2829 "discarding frag %u\n", 2830 PPP_MP_CB(p)->sequence); 2831 __skb_unlink(p, list); 2832 kfree_skb(p); 2833 } 2834 head = skb_peek(list); 2835 if (!head) 2836 break; 2837 } 2838 ++seq; 2839 } 2840 2841 /* If we have a complete packet, copy it all into one skb. */ 2842 if (tail != NULL) { 2843 /* If we have discarded any fragments, 2844 signal a receive error. */ 2845 if (PPP_MP_CB(head)->sequence != ppp->nextseq) { 2846 skb_queue_walk_safe(list, p, tmp) { 2847 if (p == head) 2848 break; 2849 if (READ_ONCE(ppp->debug) & 1) 2850 netdev_printk(KERN_DEBUG, ppp->dev, 2851 "discarding frag %u\n", 2852 PPP_MP_CB(p)->sequence); 2853 __skb_unlink(p, list); 2854 kfree_skb(p); 2855 } 2856 2857 if (READ_ONCE(ppp->debug) & 1) 2858 netdev_printk(KERN_DEBUG, ppp->dev, 2859 " missed pkts %u..%u\n", 2860 ppp->nextseq, 2861 PPP_MP_CB(head)->sequence-1); 2862 DEV_STATS_INC(ppp->dev, rx_dropped); 2863 ppp_receive_error(ppp); 2864 } 2865 2866 skb = head; 2867 if (head != tail) { 2868 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list; 2869 p = skb_queue_next(list, head); 2870 __skb_unlink(skb, list); 2871 skb_queue_walk_from_safe(list, p, tmp) { 2872 __skb_unlink(p, list); 2873 *fragpp = p; 2874 p->next = NULL; 2875 fragpp = &p->next; 2876 2877 skb->len += p->len; 2878 skb->data_len += p->len; 2879 skb->truesize += p->truesize; 2880 2881 if (p == tail) 2882 break; 2883 } 2884 } else { 2885 __skb_unlink(skb, list); 2886 } 2887 2888 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1; 2889 } 2890 2891 return skb; 2892 } 2893 #endif /* CONFIG_PPP_MULTILINK */ 2894 2895 /* 2896 * Channel interface. 2897 */ 2898 2899 /* Create a new, unattached ppp channel. */ 2900 int ppp_register_channel(struct ppp_channel *chan) 2901 { 2902 return ppp_register_net_channel(current->nsproxy->net_ns, chan); 2903 } 2904 2905 /* Create a new, unattached ppp channel for specified net. */ 2906 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan) 2907 { 2908 struct channel *pch; 2909 struct ppp_net *pn; 2910 2911 pch = kzalloc_obj(struct channel); 2912 if (!pch) 2913 return -ENOMEM; 2914 2915 pn = ppp_pernet(net); 2916 2917 pch->chan = chan; 2918 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL); 2919 chan->ppp = pch; 2920 init_ppp_file(&pch->file, CHANNEL); 2921 pch->file.hdrlen = chan->hdrlen; 2922 #ifdef CONFIG_PPP_MULTILINK 2923 pch->lastseq = -1; 2924 #endif /* CONFIG_PPP_MULTILINK */ 2925 init_rwsem(&pch->chan_sem); 2926 spin_lock_init(&pch->downl); 2927 spin_lock_init(&pch->upl); 2928 2929 spin_lock_bh(&pn->all_channels_lock); 2930 pch->file.index = ++pn->last_channel_index; 2931 list_add(&pch->list, &pn->new_channels); 2932 atomic_inc(&channel_count); 2933 spin_unlock_bh(&pn->all_channels_lock); 2934 2935 return 0; 2936 } 2937 2938 /* 2939 * Return the index of a channel. 2940 */ 2941 int ppp_channel_index(struct ppp_channel *chan) 2942 { 2943 struct channel *pch = chan->ppp; 2944 2945 if (pch) 2946 return pch->file.index; 2947 return -1; 2948 } 2949 2950 /* 2951 * Return the PPP unit number to which a channel is connected. 2952 */ 2953 int ppp_unit_number(struct ppp_channel *chan) 2954 { 2955 struct channel *pch = chan->ppp; 2956 struct ppp *ppp; 2957 int unit = -1; 2958 2959 if (pch) { 2960 rcu_read_lock(); 2961 ppp = rcu_dereference(pch->ppp); 2962 if (ppp) 2963 unit = ppp->file.index; 2964 rcu_read_unlock(); 2965 } 2966 return unit; 2967 } 2968 2969 /* 2970 * Return the PPP device interface name of a channel. 2971 * Caller must hold RCU read lock. 2972 */ 2973 char *ppp_dev_name(struct ppp_channel *chan) 2974 { 2975 struct channel *pch = chan->ppp; 2976 char *name = NULL; 2977 struct ppp *ppp; 2978 2979 if (pch) { 2980 ppp = rcu_dereference(pch->ppp); 2981 if (ppp && ppp->dev) 2982 name = ppp->dev->name; 2983 } 2984 return name; 2985 } 2986 2987 2988 /* 2989 * Disconnect a channel from the generic layer. 2990 * This must be called in process context. 2991 */ 2992 void 2993 ppp_unregister_channel(struct ppp_channel *chan) 2994 { 2995 struct channel *pch = chan->ppp; 2996 struct ppp_net *pn; 2997 2998 if (!pch) 2999 return; /* should never happen */ 3000 3001 chan->ppp = NULL; 3002 3003 /* 3004 * This ensures that we have returned from any calls into 3005 * the channel's start_xmit or ioctl routine before we proceed. 3006 */ 3007 ppp_disconnect_channel(pch); 3008 down_write(&pch->chan_sem); 3009 spin_lock_bh(&pch->downl); 3010 pch->chan = NULL; 3011 spin_unlock_bh(&pch->downl); 3012 up_write(&pch->chan_sem); 3013 3014 pn = ppp_pernet(pch->chan_net); 3015 spin_lock_bh(&pn->all_channels_lock); 3016 list_del(&pch->list); 3017 spin_unlock_bh(&pn->all_channels_lock); 3018 3019 ppp_unbridge_channels(pch); 3020 3021 pch->file.dead = 1; 3022 wake_up_interruptible(&pch->file.rwait); 3023 3024 ppp_release_channel(pch); 3025 } 3026 3027 /* 3028 * Callback from a channel when it can accept more to transmit. 3029 * This should be called at BH/softirq level, not interrupt level. 3030 */ 3031 void 3032 ppp_output_wakeup(struct ppp_channel *chan) 3033 { 3034 struct channel *pch = chan->ppp; 3035 3036 if (!pch) 3037 return; 3038 ppp_channel_push(pch); 3039 } 3040 3041 /* 3042 * Compression control. 3043 */ 3044 3045 /* Process the PPPIOCSCOMPRESS ioctl. */ 3046 static int 3047 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data) 3048 { 3049 int err = -EFAULT; 3050 struct compressor *cp, *ocomp; 3051 void *state, *ostate; 3052 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH]; 3053 3054 if (data->length > CCP_MAX_OPTION_LENGTH) 3055 goto out; 3056 if (copy_from_user(ccp_option, data->ptr, data->length)) 3057 goto out; 3058 3059 err = -EINVAL; 3060 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length) 3061 goto out; 3062 3063 cp = try_then_request_module( 3064 find_compressor(ccp_option[0]), 3065 "ppp-compress-%d", ccp_option[0]); 3066 if (!cp) 3067 goto out; 3068 3069 err = -ENOBUFS; 3070 if (data->transmit) { 3071 state = cp->comp_alloc(ccp_option, data->length); 3072 if (state) { 3073 ppp_xmit_lock(ppp); 3074 ppp->xstate &= ~SC_COMP_RUN; 3075 ocomp = ppp->xcomp; 3076 ostate = ppp->xc_state; 3077 ppp->xcomp = cp; 3078 ppp->xc_state = state; 3079 ppp_xmit_unlock(ppp); 3080 if (ostate) { 3081 ocomp->comp_free(ostate); 3082 module_put(ocomp->owner); 3083 } 3084 err = 0; 3085 } else 3086 module_put(cp->owner); 3087 3088 } else { 3089 state = cp->decomp_alloc(ccp_option, data->length); 3090 if (state) { 3091 ppp_recv_lock(ppp); 3092 ppp->rstate &= ~SC_DECOMP_RUN; 3093 ocomp = ppp->rcomp; 3094 ostate = ppp->rc_state; 3095 ppp->rcomp = cp; 3096 ppp->rc_state = state; 3097 ppp_recv_unlock(ppp); 3098 if (ostate) { 3099 ocomp->decomp_free(ostate); 3100 module_put(ocomp->owner); 3101 } 3102 err = 0; 3103 } else 3104 module_put(cp->owner); 3105 } 3106 3107 out: 3108 return err; 3109 } 3110 3111 /* 3112 * Look at a CCP packet and update our state accordingly. 3113 * We assume the caller has the xmit or recv path locked. 3114 */ 3115 static void 3116 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound) 3117 { 3118 unsigned char *dp; 3119 int len; 3120 3121 if (!pskb_may_pull(skb, CCP_HDRLEN + 2)) 3122 return; /* no header */ 3123 dp = skb->data + 2; 3124 3125 switch (CCP_CODE(dp)) { 3126 case CCP_CONFREQ: 3127 3128 /* A ConfReq starts negotiation of compression 3129 * in one direction of transmission, 3130 * and hence brings it down...but which way? 3131 * 3132 * Remember: 3133 * A ConfReq indicates what the sender would like to receive 3134 */ 3135 if(inbound) 3136 /* He is proposing what I should send */ 3137 ppp->xstate &= ~SC_COMP_RUN; 3138 else 3139 /* I am proposing to what he should send */ 3140 ppp->rstate &= ~SC_DECOMP_RUN; 3141 3142 break; 3143 3144 case CCP_TERMREQ: 3145 case CCP_TERMACK: 3146 /* 3147 * CCP is going down, both directions of transmission 3148 */ 3149 ppp->rstate &= ~SC_DECOMP_RUN; 3150 ppp->xstate &= ~SC_COMP_RUN; 3151 break; 3152 3153 case CCP_CONFACK: 3154 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN) 3155 break; 3156 len = CCP_LENGTH(dp); 3157 if (!pskb_may_pull(skb, len + 2)) 3158 return; /* too short */ 3159 dp += CCP_HDRLEN; 3160 len -= CCP_HDRLEN; 3161 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp)) 3162 break; 3163 if (inbound) { 3164 /* we will start receiving compressed packets */ 3165 if (!ppp->rc_state) 3166 break; 3167 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len, 3168 ppp->file.index, 0, ppp->mru, 3169 READ_ONCE(ppp->debug))) { 3170 ppp->rstate |= SC_DECOMP_RUN; 3171 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR); 3172 } 3173 } else { 3174 /* we will soon start sending compressed packets */ 3175 if (!ppp->xc_state) 3176 break; 3177 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len, 3178 ppp->file.index, 0, 3179 READ_ONCE(ppp->debug))) 3180 ppp->xstate |= SC_COMP_RUN; 3181 } 3182 break; 3183 3184 case CCP_RESETACK: 3185 /* reset the [de]compressor */ 3186 if ((ppp->flags & SC_CCP_UP) == 0) 3187 break; 3188 if (inbound) { 3189 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) { 3190 ppp->rcomp->decomp_reset(ppp->rc_state); 3191 ppp->rstate &= ~SC_DC_ERROR; 3192 } 3193 } else { 3194 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN)) 3195 ppp->xcomp->comp_reset(ppp->xc_state); 3196 } 3197 break; 3198 } 3199 } 3200 3201 /* Free up compression resources. */ 3202 static void 3203 ppp_ccp_closed(struct ppp *ppp) 3204 { 3205 void *xstate, *rstate; 3206 struct compressor *xcomp, *rcomp; 3207 3208 ppp_lock(ppp); 3209 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP); 3210 ppp->xstate = 0; 3211 xcomp = ppp->xcomp; 3212 xstate = ppp->xc_state; 3213 ppp->xc_state = NULL; 3214 ppp->rstate = 0; 3215 rcomp = ppp->rcomp; 3216 rstate = ppp->rc_state; 3217 ppp->rc_state = NULL; 3218 ppp_unlock(ppp); 3219 3220 if (xstate) { 3221 xcomp->comp_free(xstate); 3222 module_put(xcomp->owner); 3223 } 3224 if (rstate) { 3225 rcomp->decomp_free(rstate); 3226 module_put(rcomp->owner); 3227 } 3228 } 3229 3230 /* List of compressors. */ 3231 static LIST_HEAD(compressor_list); 3232 static DEFINE_SPINLOCK(compressor_list_lock); 3233 3234 struct compressor_entry { 3235 struct list_head list; 3236 struct compressor *comp; 3237 }; 3238 3239 static struct compressor_entry * 3240 find_comp_entry(int proto) 3241 { 3242 struct compressor_entry *ce; 3243 3244 list_for_each_entry(ce, &compressor_list, list) { 3245 if (ce->comp->compress_proto == proto) 3246 return ce; 3247 } 3248 return NULL; 3249 } 3250 3251 /* Register a compressor */ 3252 int 3253 ppp_register_compressor(struct compressor *cp) 3254 { 3255 struct compressor_entry *ce; 3256 int ret; 3257 spin_lock(&compressor_list_lock); 3258 ret = -EEXIST; 3259 if (find_comp_entry(cp->compress_proto)) 3260 goto out; 3261 ret = -ENOMEM; 3262 ce = kmalloc_obj(struct compressor_entry, GFP_ATOMIC); 3263 if (!ce) 3264 goto out; 3265 ret = 0; 3266 ce->comp = cp; 3267 list_add(&ce->list, &compressor_list); 3268 out: 3269 spin_unlock(&compressor_list_lock); 3270 return ret; 3271 } 3272 3273 /* Unregister a compressor */ 3274 void 3275 ppp_unregister_compressor(struct compressor *cp) 3276 { 3277 struct compressor_entry *ce; 3278 3279 spin_lock(&compressor_list_lock); 3280 ce = find_comp_entry(cp->compress_proto); 3281 if (ce && ce->comp == cp) { 3282 list_del(&ce->list); 3283 kfree(ce); 3284 } 3285 spin_unlock(&compressor_list_lock); 3286 } 3287 3288 /* Find a compressor. */ 3289 static struct compressor * 3290 find_compressor(int type) 3291 { 3292 struct compressor_entry *ce; 3293 struct compressor *cp = NULL; 3294 3295 spin_lock(&compressor_list_lock); 3296 ce = find_comp_entry(type); 3297 if (ce) { 3298 cp = ce->comp; 3299 if (!try_module_get(cp->owner)) 3300 cp = NULL; 3301 } 3302 spin_unlock(&compressor_list_lock); 3303 return cp; 3304 } 3305 3306 /* 3307 * Miscelleneous stuff. 3308 */ 3309 3310 static void 3311 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st) 3312 { 3313 struct slcompress *vj = ppp->vj; 3314 int cpu; 3315 3316 memset(st, 0, sizeof(*st)); 3317 for_each_possible_cpu(cpu) { 3318 struct pcpu_sw_netstats *p = per_cpu_ptr(ppp->dev->tstats, cpu); 3319 u64 rx_packets, rx_bytes, tx_packets, tx_bytes; 3320 3321 rx_packets = u64_stats_read(&p->rx_packets); 3322 rx_bytes = u64_stats_read(&p->rx_bytes); 3323 tx_packets = u64_stats_read(&p->tx_packets); 3324 tx_bytes = u64_stats_read(&p->tx_bytes); 3325 3326 st->p.ppp_ipackets += rx_packets; 3327 st->p.ppp_ibytes += rx_bytes; 3328 st->p.ppp_opackets += tx_packets; 3329 st->p.ppp_obytes += tx_bytes; 3330 } 3331 st->p.ppp_ierrors = DEV_STATS_READ(ppp->dev, rx_errors); 3332 st->p.ppp_oerrors = DEV_STATS_READ(ppp->dev, tx_errors); 3333 if (!vj) 3334 return; 3335 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed; 3336 st->vj.vjs_compressed = vj->sls_o_compressed; 3337 st->vj.vjs_searches = vj->sls_o_searches; 3338 st->vj.vjs_misses = vj->sls_o_misses; 3339 st->vj.vjs_errorin = vj->sls_i_error; 3340 st->vj.vjs_tossed = vj->sls_i_tossed; 3341 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed; 3342 st->vj.vjs_compressedin = vj->sls_i_compressed; 3343 } 3344 3345 /* 3346 * Stuff for handling the lists of ppp units and channels 3347 * and for initialization. 3348 */ 3349 3350 /* 3351 * Create a new ppp interface unit. Fails if it can't allocate memory 3352 * or if there is already a unit with the requested number. 3353 * unit == -1 means allocate a new number. 3354 */ 3355 static int ppp_create_interface(struct net *net, struct file *file, int *unit) 3356 { 3357 struct ppp_config conf = { 3358 .file = file, 3359 .unit = *unit, 3360 .ifname_is_set = false, 3361 }; 3362 struct net_device *dev; 3363 struct ppp *ppp; 3364 int err; 3365 3366 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup); 3367 if (!dev) { 3368 err = -ENOMEM; 3369 goto err; 3370 } 3371 dev_net_set(dev, net); 3372 dev->rtnl_link_ops = &ppp_link_ops; 3373 3374 rtnl_lock(); 3375 3376 err = ppp_dev_configure(net, dev, &conf); 3377 if (err < 0) 3378 goto err_dev; 3379 ppp = netdev_priv(dev); 3380 *unit = ppp->file.index; 3381 3382 rtnl_unlock(); 3383 3384 return 0; 3385 3386 err_dev: 3387 rtnl_unlock(); 3388 free_netdev(dev); 3389 err: 3390 return err; 3391 } 3392 3393 /* 3394 * Initialize a ppp_file structure. 3395 */ 3396 static void 3397 init_ppp_file(struct ppp_file *pf, int kind) 3398 { 3399 pf->kind = kind; 3400 skb_queue_head_init(&pf->xq); 3401 skb_queue_head_init(&pf->rq); 3402 refcount_set(&pf->refcnt, 1); 3403 init_waitqueue_head(&pf->rwait); 3404 } 3405 3406 /* 3407 * Drop a reference to a ppp unit and free its memory if the refcount reaches 3408 * zero. 3409 */ 3410 static void ppp_release_interface(struct ppp *ppp) 3411 { 3412 if (!refcount_dec_and_test(&ppp->file.refcnt)) 3413 return; 3414 3415 atomic_dec(&ppp_unit_count); 3416 3417 if (!ppp->file.dead || ppp->n_channels) { 3418 /* "can't happen" */ 3419 netdev_err(ppp->dev, "ppp: destroying ppp struct %p " 3420 "but dead=%d n_channels=%d !\n", 3421 ppp, ppp->file.dead, ppp->n_channels); 3422 return; 3423 } 3424 3425 ppp_ccp_closed(ppp); 3426 if (ppp->vj) { 3427 slhc_free(ppp->vj); 3428 ppp->vj = NULL; 3429 } 3430 skb_queue_purge(&ppp->file.xq); 3431 skb_queue_purge(&ppp->file.rq); 3432 #ifdef CONFIG_PPP_MULTILINK 3433 skb_queue_purge(&ppp->mrq); 3434 #endif /* CONFIG_PPP_MULTILINK */ 3435 #ifdef CONFIG_PPP_FILTER 3436 if (ppp->pass_filter) { 3437 bpf_prog_destroy(ppp->pass_filter); 3438 ppp->pass_filter = NULL; 3439 } 3440 3441 if (ppp->active_filter) { 3442 bpf_prog_destroy(ppp->active_filter); 3443 ppp->active_filter = NULL; 3444 } 3445 #endif /* CONFIG_PPP_FILTER */ 3446 3447 free_percpu(ppp->xmit_recursion); 3448 3449 free_netdev(ppp->dev); 3450 } 3451 3452 /* 3453 * Locate an existing ppp unit. 3454 * The caller should have locked the all_ppp_mutex. 3455 */ 3456 static struct ppp * 3457 ppp_find_unit(struct ppp_net *pn, int unit) 3458 { 3459 return unit_find(&pn->units_idr, unit); 3460 } 3461 3462 /* 3463 * Locate an existing ppp channel. 3464 * The caller should have locked the all_channels_lock. 3465 * First we look in the new_channels list, then in the 3466 * all_channels list. If found in the new_channels list, 3467 * we move it to the all_channels list. This is for speed 3468 * when we have a lot of channels in use. 3469 */ 3470 static struct channel * 3471 ppp_find_channel(struct ppp_net *pn, int unit) 3472 { 3473 struct channel *pch; 3474 3475 list_for_each_entry(pch, &pn->new_channels, list) { 3476 if (pch->file.index == unit) { 3477 list_move(&pch->list, &pn->all_channels); 3478 return pch; 3479 } 3480 } 3481 3482 list_for_each_entry(pch, &pn->all_channels, list) { 3483 if (pch->file.index == unit) 3484 return pch; 3485 } 3486 3487 return NULL; 3488 } 3489 3490 /* 3491 * Connect a PPP channel to a PPP interface unit. 3492 */ 3493 static int 3494 ppp_connect_channel(struct channel *pch, int unit) 3495 { 3496 struct ppp *ppp; 3497 struct ppp_net *pn; 3498 int ret = -ENXIO; 3499 int hdrlen; 3500 3501 pn = ppp_pernet(pch->chan_net); 3502 3503 mutex_lock(&pn->all_ppp_mutex); 3504 ppp = ppp_find_unit(pn, unit); 3505 if (!ppp) 3506 goto out; 3507 spin_lock(&pch->upl); 3508 ret = -EINVAL; 3509 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) || 3510 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) 3511 goto outl; 3512 3513 ppp_lock(ppp); 3514 spin_lock_bh(&pch->downl); 3515 if (!pch->chan) { 3516 /* Don't connect unregistered channels */ 3517 spin_unlock_bh(&pch->downl); 3518 ppp_unlock(ppp); 3519 ret = -ENOTCONN; 3520 goto outl; 3521 } 3522 if (pch->chan->direct_xmit) 3523 ppp->dev->priv_flags |= IFF_NO_QUEUE; 3524 else 3525 ppp->dev->priv_flags &= ~IFF_NO_QUEUE; 3526 spin_unlock_bh(&pch->downl); 3527 if (pch->file.hdrlen > ppp->file.hdrlen) 3528 ppp->file.hdrlen = pch->file.hdrlen; 3529 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */ 3530 if (hdrlen > ppp->dev->hard_header_len) 3531 ppp->dev->hard_header_len = hdrlen; 3532 list_add_tail_rcu(&pch->clist, &ppp->channels); 3533 ++ppp->n_channels; 3534 rcu_assign_pointer(pch->ppp, ppp); 3535 refcount_inc(&ppp->file.refcnt); 3536 ppp_unlock(ppp); 3537 ret = 0; 3538 3539 outl: 3540 spin_unlock(&pch->upl); 3541 out: 3542 mutex_unlock(&pn->all_ppp_mutex); 3543 return ret; 3544 } 3545 3546 /* 3547 * Disconnect a channel from its ppp unit. 3548 */ 3549 static int 3550 ppp_disconnect_channel(struct channel *pch) 3551 { 3552 struct ppp *ppp; 3553 int err = -EINVAL; 3554 3555 spin_lock(&pch->upl); 3556 ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl)); 3557 spin_unlock(&pch->upl); 3558 if (ppp) { 3559 /* remove it from the ppp unit's list */ 3560 ppp_lock(ppp); 3561 list_del_rcu(&pch->clist); 3562 if (--ppp->n_channels == 0) 3563 wake_up_interruptible(&ppp->file.rwait); 3564 ppp_unlock(ppp); 3565 synchronize_net(); 3566 ppp_release_interface(ppp); 3567 err = 0; 3568 } 3569 return err; 3570 } 3571 3572 /* Purge after the grace period: a late ppp_input() may still queue an 3573 * skb on pch->file.rq before the last RCU reader drains. 3574 */ 3575 static void ppp_release_channel_free(struct rcu_head *rcu) 3576 { 3577 struct channel *pch = container_of(rcu, struct channel, rcu); 3578 3579 skb_queue_purge(&pch->file.xq); 3580 skb_queue_purge(&pch->file.rq); 3581 kfree(pch); 3582 } 3583 3584 /* 3585 * Drop a reference to a ppp channel and free its memory if the refcount reaches 3586 * zero. 3587 */ 3588 static void ppp_release_channel(struct channel *pch) 3589 { 3590 if (!refcount_dec_and_test(&pch->file.refcnt)) 3591 return; 3592 3593 put_net_track(pch->chan_net, &pch->ns_tracker); 3594 pch->chan_net = NULL; 3595 3596 atomic_dec(&channel_count); 3597 3598 if (!pch->file.dead) { 3599 /* "can't happen" */ 3600 pr_err("ppp: destroying undead channel %p !\n", pch); 3601 return; 3602 } 3603 call_rcu(&pch->rcu, ppp_release_channel_free); 3604 } 3605 3606 static void __exit ppp_cleanup(void) 3607 { 3608 /* should never happen */ 3609 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count)) 3610 pr_err("PPP: removing module but units remain!\n"); 3611 rtnl_link_unregister(&ppp_link_ops); 3612 unregister_chrdev(PPP_MAJOR, "ppp"); 3613 device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0)); 3614 class_unregister(&ppp_class); 3615 unregister_pernet_device(&ppp_net_ops); 3616 rcu_barrier(); /* wait for RCU callbacks before module unload */ 3617 } 3618 3619 /* 3620 * Units handling. Caller must protect concurrent access 3621 * by holding all_ppp_mutex 3622 */ 3623 3624 /* associate pointer with specified number */ 3625 static int unit_set(struct idr *p, void *ptr, int n) 3626 { 3627 int unit; 3628 3629 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL); 3630 if (unit == -ENOSPC) 3631 unit = -EINVAL; 3632 return unit; 3633 } 3634 3635 /* get new free unit number and associate pointer with it */ 3636 static int unit_get(struct idr *p, void *ptr, int min) 3637 { 3638 return idr_alloc(p, ptr, min, 0, GFP_KERNEL); 3639 } 3640 3641 /* put unit number back to a pool */ 3642 static void unit_put(struct idr *p, int n) 3643 { 3644 idr_remove(p, n); 3645 } 3646 3647 /* get pointer associated with the number */ 3648 static void *unit_find(struct idr *p, int n) 3649 { 3650 return idr_find(p, n); 3651 } 3652 3653 /* Module/initialization stuff */ 3654 3655 module_init(ppp_init); 3656 module_exit(ppp_cleanup); 3657 3658 EXPORT_SYMBOL(ppp_register_net_channel); 3659 EXPORT_SYMBOL(ppp_register_channel); 3660 EXPORT_SYMBOL(ppp_unregister_channel); 3661 EXPORT_SYMBOL(ppp_channel_index); 3662 EXPORT_SYMBOL(ppp_unit_number); 3663 EXPORT_SYMBOL(ppp_dev_name); 3664 EXPORT_SYMBOL(ppp_input); 3665 EXPORT_SYMBOL(ppp_input_error); 3666 EXPORT_SYMBOL(ppp_output_wakeup); 3667 EXPORT_SYMBOL(ppp_register_compressor); 3668 EXPORT_SYMBOL(ppp_unregister_compressor); 3669 MODULE_DESCRIPTION("Generic PPP layer driver"); 3670 MODULE_LICENSE("GPL"); 3671 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0); 3672 MODULE_ALIAS_RTNL_LINK("ppp"); 3673 MODULE_ALIAS("devname:ppp"); 3674