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/stddef.h> 43 #include <linux/device.h> 44 #include <linux/mutex.h> 45 #include <linux/slab.h> 46 #include <linux/file.h> 47 #include <linux/unaligned.h> 48 #include <net/gso.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 int closing; /* is device closing down? a8 */ 144 #ifdef CONFIG_PPP_MULTILINK 145 int nxchan; /* next channel to send something on */ 146 u32 nxseq; /* next sequence number to send */ 147 int mrru; /* MP: max reconst. receive unit */ 148 u32 nextseq; /* MP: seq no of next packet */ 149 u32 minseq; /* MP: min of most recent seqnos */ 150 struct sk_buff_head mrq; /* MP: receive reconstruction queue */ 151 #endif /* CONFIG_PPP_MULTILINK */ 152 #ifdef CONFIG_PPP_FILTER 153 struct bpf_prog *pass_filter; /* filter for packets to pass */ 154 struct bpf_prog *active_filter; /* filter for pkts to reset idle */ 155 #endif /* CONFIG_PPP_FILTER */ 156 struct net *ppp_net; /* the net we belong to */ 157 }; 158 159 /* 160 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC, 161 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP, 162 * SC_MUST_COMP 163 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR. 164 * Bits in xstate: SC_COMP_RUN 165 */ 166 #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \ 167 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \ 168 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP) 169 170 /* 171 * Private data structure for each channel. 172 * This includes the data structure used for multilink. 173 */ 174 struct channel { 175 struct ppp_file file; /* stuff for read/write/poll */ 176 struct list_head list; /* link in all/new_channels list */ 177 struct ppp_channel *chan; /* public channel data structure */ 178 struct mutex chan_sem; /* protects `chan' during chan ioctl */ 179 spinlock_t downl; /* protects `chan', file.xq dequeue */ 180 struct ppp __rcu *ppp; /* ppp unit we're connected to */ 181 struct net *chan_net; /* the net channel belongs to */ 182 netns_tracker ns_tracker; 183 struct list_head clist; /* link in list of channels per unit */ 184 spinlock_t upl; /* protects `ppp' and 'bridge' */ 185 struct channel __rcu *bridge; /* "bridged" ppp channel */ 186 struct rcu_head rcu; /* for RCU-deferred free of the channel */ 187 #ifdef CONFIG_PPP_MULTILINK 188 u8 avail; /* flag used in multilink stuff */ 189 u8 had_frag; /* >= 1 fragments have been sent */ 190 u32 lastseq; /* MP: last sequence # received */ 191 int speed; /* speed of the corresponding ppp channel*/ 192 #endif /* CONFIG_PPP_MULTILINK */ 193 }; 194 195 struct ppp_config { 196 struct file *file; 197 s32 unit; 198 bool ifname_is_set; 199 }; 200 201 /* 202 * SMP locking issues: 203 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels 204 * list and the ppp.n_channels field, you need to take both locks 205 * before you modify them. 206 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock -> 207 * channel.downl. 208 */ 209 210 static DEFINE_MUTEX(ppp_mutex); 211 static atomic_t ppp_unit_count = ATOMIC_INIT(0); 212 static atomic_t channel_count = ATOMIC_INIT(0); 213 214 /* per-net private data for this module */ 215 static unsigned int ppp_net_id __read_mostly; 216 struct ppp_net { 217 /* units to ppp mapping */ 218 struct idr units_idr; 219 220 /* 221 * all_ppp_mutex protects the units_idr mapping. 222 * It also ensures that finding a ppp unit in the units_idr 223 * map and updating its file.refcnt field is atomic. 224 */ 225 struct mutex all_ppp_mutex; 226 227 /* channels */ 228 struct list_head all_channels; 229 struct list_head new_channels; 230 int last_channel_index; 231 232 /* 233 * all_channels_lock protects all_channels and 234 * last_channel_index, and the atomicity of find 235 * a channel and updating its file.refcnt field. 236 */ 237 spinlock_t all_channels_lock; 238 }; 239 240 /* Get the PPP protocol number from a skb */ 241 #define PPP_PROTO(skb) get_unaligned_be16((skb)->data) 242 243 /* We limit the length of ppp->file.rq to this (arbitrary) value */ 244 #define PPP_MAX_RQLEN 32 245 246 /* 247 * Maximum number of multilink fragments queued up. 248 * This has to be large enough to cope with the maximum latency of 249 * the slowest channel relative to the others. Strictly it should 250 * depend on the number of channels and their characteristics. 251 */ 252 #define PPP_MP_MAX_QLEN 128 253 254 /* Multilink header bits. */ 255 #define B 0x80 /* this fragment begins a packet */ 256 #define E 0x40 /* this fragment ends a packet */ 257 258 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */ 259 #define seq_before(a, b) ((s32)((a) - (b)) < 0) 260 #define seq_after(a, b) ((s32)((a) - (b)) > 0) 261 262 /* Prototypes. */ 263 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, 264 struct file *file, unsigned int cmd, unsigned long arg); 265 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb); 266 static int ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb); 267 static int ppp_push(struct ppp *ppp, struct sk_buff *skb); 268 static void ppp_channel_push(struct channel *pch); 269 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, 270 struct channel *pch); 271 static void ppp_receive_error(struct ppp *ppp); 272 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb); 273 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp, 274 struct sk_buff *skb); 275 #ifdef CONFIG_PPP_MULTILINK 276 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, 277 struct channel *pch); 278 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb); 279 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp); 280 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb); 281 #endif /* CONFIG_PPP_MULTILINK */ 282 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data); 283 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound); 284 static void ppp_ccp_closed(struct ppp *ppp); 285 static struct compressor *find_compressor(int type); 286 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st); 287 static int ppp_create_interface(struct net *net, struct file *file, int *unit); 288 static void init_ppp_file(struct ppp_file *pf, int kind); 289 static void ppp_release_interface(struct ppp *ppp); 290 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit); 291 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit); 292 static int ppp_connect_channel(struct channel *pch, int unit); 293 static int ppp_disconnect_channel(struct channel *pch); 294 static void ppp_release_channel(struct channel *pch); 295 static int unit_get(struct idr *p, void *ptr, int min); 296 static int unit_set(struct idr *p, void *ptr, int n); 297 static void unit_put(struct idr *p, int n); 298 static void *unit_find(struct idr *p, int n); 299 static void ppp_setup(struct net_device *dev); 300 301 static const struct net_device_ops ppp_netdev_ops; 302 303 static const struct class ppp_class = { 304 .name = "ppp", 305 }; 306 307 /* per net-namespace data */ 308 static inline struct ppp_net *ppp_pernet(struct net *net) 309 { 310 return net_generic(net, ppp_net_id); 311 } 312 313 /* Translates a PPP protocol number to a NP index (NP == network protocol) */ 314 static inline int proto_to_npindex(int proto) 315 { 316 switch (proto) { 317 case PPP_IP: 318 return NP_IP; 319 case PPP_IPV6: 320 return NP_IPV6; 321 case PPP_IPX: 322 return NP_IPX; 323 case PPP_AT: 324 return NP_AT; 325 case PPP_MPLS_UC: 326 return NP_MPLS_UC; 327 case PPP_MPLS_MC: 328 return NP_MPLS_MC; 329 } 330 return -EINVAL; 331 } 332 333 /* Translates an NP index into a PPP protocol number */ 334 static const int npindex_to_proto[NUM_NP] = { 335 PPP_IP, 336 PPP_IPV6, 337 PPP_IPX, 338 PPP_AT, 339 PPP_MPLS_UC, 340 PPP_MPLS_MC, 341 }; 342 343 /* Translates an ethertype into an NP index */ 344 static inline int ethertype_to_npindex(int ethertype) 345 { 346 switch (ethertype) { 347 case ETH_P_IP: 348 return NP_IP; 349 case ETH_P_IPV6: 350 return NP_IPV6; 351 case ETH_P_IPX: 352 return NP_IPX; 353 case ETH_P_PPPTALK: 354 case ETH_P_ATALK: 355 return NP_AT; 356 case ETH_P_MPLS_UC: 357 return NP_MPLS_UC; 358 case ETH_P_MPLS_MC: 359 return NP_MPLS_MC; 360 } 361 return -1; 362 } 363 364 /* Translates an NP index into an ethertype */ 365 static const int npindex_to_ethertype[NUM_NP] = { 366 ETH_P_IP, 367 ETH_P_IPV6, 368 ETH_P_IPX, 369 ETH_P_PPPTALK, 370 ETH_P_MPLS_UC, 371 ETH_P_MPLS_MC, 372 }; 373 374 /* 375 * Locking shorthand. 376 */ 377 #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock) 378 #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock) 379 #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock) 380 #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock) 381 #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \ 382 ppp_recv_lock(ppp); } while (0) 383 #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \ 384 ppp_xmit_unlock(ppp); } while (0) 385 386 /* 387 * /dev/ppp device routines. 388 * The /dev/ppp device is used by pppd to control the ppp unit. 389 * It supports the read, write, ioctl and poll functions. 390 * Open instances of /dev/ppp can be in one of three states: 391 * unattached, attached to a ppp unit, or attached to a ppp channel. 392 */ 393 static int ppp_open(struct inode *inode, struct file *file) 394 { 395 /* 396 * This could (should?) be enforced by the permissions on /dev/ppp. 397 */ 398 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN)) 399 return -EPERM; 400 return 0; 401 } 402 403 static int ppp_release(struct inode *unused, struct file *file) 404 { 405 struct ppp_file *pf = file->private_data; 406 struct ppp *ppp; 407 408 if (pf) { 409 file->private_data = NULL; 410 switch (pf->kind) { 411 case INTERFACE: 412 ppp = PF_TO_PPP(pf); 413 rtnl_lock(); 414 if (file == ppp->owner) 415 unregister_netdevice(netdev_from_priv(ppp)); 416 rtnl_unlock(); 417 ppp_release_interface(ppp); 418 break; 419 case CHANNEL: 420 ppp_release_channel(PF_TO_CHANNEL(pf)); 421 break; 422 } 423 } 424 return 0; 425 } 426 427 static ssize_t ppp_read(struct file *file, char __user *buf, 428 size_t count, loff_t *ppos) 429 { 430 struct ppp_file *pf = file->private_data; 431 DECLARE_WAITQUEUE(wait, current); 432 ssize_t ret; 433 struct sk_buff *skb = NULL; 434 struct iovec iov; 435 struct iov_iter to; 436 437 ret = count; 438 439 if (!pf) 440 return -ENXIO; 441 add_wait_queue(&pf->rwait, &wait); 442 for (;;) { 443 set_current_state(TASK_INTERRUPTIBLE); 444 skb = skb_dequeue(&pf->rq); 445 if (skb) 446 break; 447 ret = 0; 448 if (pf->dead) 449 break; 450 if (pf->kind == INTERFACE) { 451 /* 452 * Return 0 (EOF) on an interface that has no 453 * channels connected, unless it is looping 454 * network traffic (demand mode). 455 */ 456 struct ppp *ppp = PF_TO_PPP(pf); 457 458 ppp_recv_lock(ppp); 459 if (ppp->n_channels == 0 && 460 (ppp->flags & SC_LOOP_TRAFFIC) == 0) { 461 ppp_recv_unlock(ppp); 462 break; 463 } 464 ppp_recv_unlock(ppp); 465 } 466 ret = -EAGAIN; 467 if (file->f_flags & O_NONBLOCK) 468 break; 469 ret = -ERESTARTSYS; 470 if (signal_pending(current)) 471 break; 472 schedule(); 473 } 474 set_current_state(TASK_RUNNING); 475 remove_wait_queue(&pf->rwait, &wait); 476 477 if (!skb) 478 goto out; 479 480 ret = -EOVERFLOW; 481 if (skb->len > count) 482 goto outf; 483 ret = -EFAULT; 484 iov.iov_base = buf; 485 iov.iov_len = count; 486 iov_iter_init(&to, ITER_DEST, &iov, 1, count); 487 if (skb_copy_datagram_iter(skb, 0, &to, skb->len)) 488 goto outf; 489 ret = skb->len; 490 491 outf: 492 kfree_skb(skb); 493 out: 494 return ret; 495 } 496 497 static bool ppp_check_packet(struct sk_buff *skb, size_t count) 498 { 499 /* LCP packets must include LCP header which 4 bytes long: 500 * 1-byte code, 1-byte identifier, and 2-byte length. 501 */ 502 return get_unaligned_be16(skb->data) != PPP_LCP || 503 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN; 504 } 505 506 static ssize_t ppp_write(struct file *file, const char __user *buf, 507 size_t count, loff_t *ppos) 508 { 509 struct ppp_file *pf = file->private_data; 510 struct sk_buff *skb; 511 ssize_t ret; 512 513 if (!pf) 514 return -ENXIO; 515 /* All PPP packets should start with the 2-byte protocol */ 516 if (count < PPP_PROTO_LEN) 517 return -EINVAL; 518 ret = -ENOMEM; 519 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL); 520 if (!skb) 521 goto out; 522 skb_reserve(skb, pf->hdrlen); 523 ret = -EFAULT; 524 if (copy_from_user(skb_put(skb, count), buf, count)) { 525 kfree_skb(skb); 526 goto out; 527 } 528 ret = -EINVAL; 529 if (unlikely(!ppp_check_packet(skb, count))) { 530 kfree_skb(skb); 531 goto out; 532 } 533 534 switch (pf->kind) { 535 case INTERFACE: 536 ppp_xmit_process(PF_TO_PPP(pf), skb); 537 break; 538 case CHANNEL: 539 skb_queue_tail(&pf->xq, skb); 540 ppp_channel_push(PF_TO_CHANNEL(pf)); 541 break; 542 } 543 544 ret = count; 545 546 out: 547 return ret; 548 } 549 550 /* No kernel lock - fine */ 551 static __poll_t ppp_poll(struct file *file, poll_table *wait) 552 { 553 struct ppp_file *pf = file->private_data; 554 __poll_t mask; 555 556 if (!pf) 557 return 0; 558 poll_wait(file, &pf->rwait, wait); 559 mask = EPOLLOUT | EPOLLWRNORM; 560 if (!skb_queue_empty_lockless(&pf->rq)) 561 mask |= EPOLLIN | EPOLLRDNORM; 562 if (pf->dead) 563 mask |= EPOLLHUP; 564 else if (pf->kind == INTERFACE) { 565 /* see comment in ppp_read */ 566 struct ppp *ppp = PF_TO_PPP(pf); 567 568 ppp_recv_lock(ppp); 569 if (ppp->n_channels == 0 && 570 (ppp->flags & SC_LOOP_TRAFFIC) == 0) 571 mask |= EPOLLIN | EPOLLRDNORM; 572 ppp_recv_unlock(ppp); 573 } 574 575 return mask; 576 } 577 578 #ifdef CONFIG_PPP_FILTER 579 static struct bpf_prog *get_filter(struct sock_fprog *uprog) 580 { 581 struct sock_fprog_kern fprog; 582 struct bpf_prog *res = NULL; 583 int err; 584 585 if (!uprog->len) 586 return NULL; 587 588 /* uprog->len is unsigned short, so no overflow here */ 589 fprog.len = uprog->len; 590 fprog.filter = memdup_array_user(uprog->filter, 591 uprog->len, sizeof(struct sock_filter)); 592 if (IS_ERR(fprog.filter)) 593 return ERR_CAST(fprog.filter); 594 595 err = bpf_prog_create(&res, &fprog); 596 kfree(fprog.filter); 597 598 return err ? ERR_PTR(err) : res; 599 } 600 601 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p) 602 { 603 struct sock_fprog uprog; 604 605 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog))) 606 return ERR_PTR(-EFAULT); 607 return get_filter(&uprog); 608 } 609 610 #ifdef CONFIG_COMPAT 611 struct sock_fprog32 { 612 unsigned short len; 613 compat_caddr_t filter; 614 }; 615 616 #define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32) 617 #define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32) 618 619 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p) 620 { 621 struct sock_fprog32 uprog32; 622 struct sock_fprog uprog; 623 624 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32))) 625 return ERR_PTR(-EFAULT); 626 uprog.len = uprog32.len; 627 uprog.filter = compat_ptr(uprog32.filter); 628 return get_filter(&uprog); 629 } 630 #endif 631 #endif 632 633 /* Bridge one PPP channel to another. 634 * When two channels are bridged, ppp_input on one channel is redirected to 635 * the other's ops->start_xmit handler. 636 * In order to safely bridge channels we must reject channels which are already 637 * part of a bridge instance, or which form part of an existing unit. 638 * Once successfully bridged, each channel holds a reference on the other 639 * to prevent it being freed while the bridge is extant. 640 */ 641 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb) 642 { 643 spin_lock(&pch->upl); 644 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) || 645 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) { 646 spin_unlock(&pch->upl); 647 return -EALREADY; 648 } 649 refcount_inc(&pchb->file.refcnt); 650 rcu_assign_pointer(pch->bridge, pchb); 651 spin_unlock(&pch->upl); 652 653 spin_lock(&pchb->upl); 654 if (rcu_dereference_protected(pchb->ppp, lockdep_is_held(&pchb->upl)) || 655 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) { 656 spin_unlock(&pchb->upl); 657 goto err_unset; 658 } 659 refcount_inc(&pch->file.refcnt); 660 rcu_assign_pointer(pchb->bridge, pch); 661 spin_unlock(&pchb->upl); 662 663 return 0; 664 665 err_unset: 666 spin_lock(&pch->upl); 667 /* Re-read pch->bridge with upl held in case it was modified concurrently */ 668 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 669 RCU_INIT_POINTER(pch->bridge, NULL); 670 spin_unlock(&pch->upl); 671 synchronize_rcu(); 672 673 if (pchb) 674 ppp_release_channel(pchb); 675 676 return -EALREADY; 677 } 678 679 static int ppp_unbridge_channels(struct channel *pch) 680 { 681 struct channel *pchb, *pchbb; 682 683 spin_lock(&pch->upl); 684 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 685 if (!pchb) { 686 spin_unlock(&pch->upl); 687 return -EINVAL; 688 } 689 RCU_INIT_POINTER(pch->bridge, NULL); 690 spin_unlock(&pch->upl); 691 692 /* Only modify pchb if phcb->bridge points back to pch. 693 * If not, it implies that there has been a race unbridging (and possibly 694 * even rebridging) pchb. We should leave pchb alone to avoid either a 695 * refcount underflow, or breaking another established bridge instance. 696 */ 697 spin_lock(&pchb->upl); 698 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl)); 699 if (pchbb == pch) 700 RCU_INIT_POINTER(pchb->bridge, NULL); 701 spin_unlock(&pchb->upl); 702 703 synchronize_rcu(); 704 705 if (pchbb == pch) 706 ppp_release_channel(pch); 707 708 ppp_release_channel(pchb); 709 710 return 0; 711 } 712 713 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 714 { 715 struct ppp_file *pf; 716 struct ppp *ppp; 717 int err = -EFAULT, val, val2, i; 718 struct ppp_idle32 idle32; 719 struct ppp_idle64 idle64; 720 struct npioctl npi; 721 int unit, cflags; 722 struct slcompress *vj; 723 void __user *argp = (void __user *)arg; 724 int __user *p = argp; 725 726 mutex_lock(&ppp_mutex); 727 728 pf = file->private_data; 729 if (!pf) { 730 err = ppp_unattached_ioctl(current->nsproxy->net_ns, 731 pf, file, cmd, arg); 732 goto out; 733 } 734 735 if (cmd == PPPIOCDETACH) { 736 /* 737 * PPPIOCDETACH is no longer supported as it was heavily broken, 738 * and is only known to have been used by pppd older than 739 * ppp-2.4.2 (released November 2003). 740 */ 741 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n", 742 current->comm, current->pid); 743 err = -EINVAL; 744 goto out; 745 } 746 747 if (pf->kind == CHANNEL) { 748 struct channel *pch, *pchb; 749 struct ppp_channel *chan; 750 struct ppp_net *pn; 751 752 pch = PF_TO_CHANNEL(pf); 753 754 switch (cmd) { 755 case PPPIOCCONNECT: 756 if (get_user(unit, p)) 757 break; 758 err = ppp_connect_channel(pch, unit); 759 break; 760 761 case PPPIOCDISCONN: 762 err = ppp_disconnect_channel(pch); 763 break; 764 765 case PPPIOCBRIDGECHAN: 766 if (get_user(unit, p)) 767 break; 768 err = -ENXIO; 769 pn = ppp_pernet(current->nsproxy->net_ns); 770 spin_lock_bh(&pn->all_channels_lock); 771 pchb = ppp_find_channel(pn, unit); 772 /* Hold a reference to prevent pchb being freed while 773 * we establish the bridge. 774 */ 775 if (pchb) 776 refcount_inc(&pchb->file.refcnt); 777 spin_unlock_bh(&pn->all_channels_lock); 778 if (!pchb) 779 break; 780 err = ppp_bridge_channels(pch, pchb); 781 /* Drop earlier refcount now bridge establishment is complete */ 782 ppp_release_channel(pchb); 783 break; 784 785 case PPPIOCUNBRIDGECHAN: 786 err = ppp_unbridge_channels(pch); 787 break; 788 789 default: 790 mutex_lock(&pch->chan_sem); 791 chan = pch->chan; 792 err = -ENOTTY; 793 if (chan && chan->ops->ioctl) 794 err = chan->ops->ioctl(chan, cmd, arg); 795 mutex_unlock(&pch->chan_sem); 796 } 797 goto out; 798 } 799 800 if (pf->kind != INTERFACE) { 801 /* can't happen */ 802 pr_err("PPP: not interface or channel??\n"); 803 err = -EINVAL; 804 goto out; 805 } 806 807 ppp = PF_TO_PPP(pf); 808 switch (cmd) { 809 case PPPIOCSMRU: 810 if (get_user(val, p)) 811 break; 812 ppp_recv_lock(ppp); 813 ppp->mru = val; 814 ppp_recv_unlock(ppp); 815 err = 0; 816 break; 817 818 case PPPIOCSFLAGS: 819 if (get_user(val, p)) 820 break; 821 ppp_lock(ppp); 822 cflags = ppp->flags & ~val; 823 #ifdef CONFIG_PPP_MULTILINK 824 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK)) 825 ppp->nextseq = 0; 826 #endif 827 ppp->flags = val & SC_FLAG_BITS; 828 ppp_unlock(ppp); 829 if (cflags & SC_CCP_OPEN) 830 ppp_ccp_closed(ppp); 831 err = 0; 832 break; 833 834 case PPPIOCGFLAGS: 835 ppp_lock(ppp); 836 val = ppp->flags | ppp->xstate | ppp->rstate; 837 ppp_unlock(ppp); 838 if (put_user(val, p)) 839 break; 840 err = 0; 841 break; 842 843 case PPPIOCSCOMPRESS: 844 { 845 struct ppp_option_data data; 846 if (copy_from_user(&data, argp, sizeof(data))) 847 err = -EFAULT; 848 else 849 err = ppp_set_compress(ppp, &data); 850 break; 851 } 852 case PPPIOCGUNIT: 853 if (put_user(ppp->file.index, p)) 854 break; 855 err = 0; 856 break; 857 858 case PPPIOCSDEBUG: 859 if (get_user(val, p)) 860 break; 861 WRITE_ONCE(ppp->debug, val); 862 err = 0; 863 break; 864 865 case PPPIOCGDEBUG: 866 if (put_user(ppp->debug, p)) 867 break; 868 err = 0; 869 break; 870 871 case PPPIOCGIDLE32: 872 idle32.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ; 873 idle32.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ; 874 if (copy_to_user(argp, &idle32, sizeof(idle32))) 875 break; 876 err = 0; 877 break; 878 879 case PPPIOCGIDLE64: 880 idle64.xmit_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_xmit))) / HZ; 881 idle64.recv_idle = max(0L, (long)(jiffies - READ_ONCE(ppp->last_recv))) / HZ; 882 if (copy_to_user(argp, &idle64, sizeof(idle64))) 883 break; 884 err = 0; 885 break; 886 887 case PPPIOCSMAXCID: 888 if (get_user(val, p)) 889 break; 890 val2 = 15; 891 if ((val >> 16) != 0) { 892 val2 = val >> 16; 893 val &= 0xffff; 894 } 895 vj = slhc_init(val2+1, val+1); 896 if (IS_ERR(vj)) { 897 err = PTR_ERR(vj); 898 break; 899 } 900 ppp_lock(ppp); 901 if (ppp->vj) 902 slhc_free(ppp->vj); 903 ppp->vj = vj; 904 ppp_unlock(ppp); 905 err = 0; 906 break; 907 908 case PPPIOCGNPMODE: 909 case PPPIOCSNPMODE: 910 if (copy_from_user(&npi, argp, sizeof(npi))) 911 break; 912 err = proto_to_npindex(npi.protocol); 913 if (err < 0) 914 break; 915 i = err; 916 if (cmd == PPPIOCGNPMODE) { 917 err = -EFAULT; 918 npi.mode = ppp->npmode[i]; 919 if (copy_to_user(argp, &npi, sizeof(npi))) 920 break; 921 } else { 922 WRITE_ONCE(ppp->npmode[i], npi.mode); 923 /* we may be able to transmit more packets now (??) */ 924 netif_wake_queue(netdev_from_priv(ppp)); 925 } 926 err = 0; 927 break; 928 929 #ifdef CONFIG_PPP_FILTER 930 case PPPIOCSPASS: 931 case PPPIOCSACTIVE: 932 { 933 struct bpf_prog *filter = ppp_get_filter(argp); 934 struct bpf_prog **which; 935 936 if (IS_ERR(filter)) { 937 err = PTR_ERR(filter); 938 break; 939 } 940 if (cmd == PPPIOCSPASS) 941 which = &ppp->pass_filter; 942 else 943 which = &ppp->active_filter; 944 ppp_lock(ppp); 945 if (*which) 946 bpf_prog_destroy(*which); 947 *which = filter; 948 ppp_unlock(ppp); 949 err = 0; 950 break; 951 } 952 #endif /* CONFIG_PPP_FILTER */ 953 954 #ifdef CONFIG_PPP_MULTILINK 955 case PPPIOCSMRRU: 956 if (get_user(val, p)) 957 break; 958 ppp_recv_lock(ppp); 959 ppp->mrru = val; 960 ppp_recv_unlock(ppp); 961 err = 0; 962 break; 963 #endif /* CONFIG_PPP_MULTILINK */ 964 965 default: 966 err = -ENOTTY; 967 } 968 969 out: 970 mutex_unlock(&ppp_mutex); 971 972 return err; 973 } 974 975 #ifdef CONFIG_COMPAT 976 struct ppp_option_data32 { 977 compat_uptr_t ptr; 978 u32 length; 979 compat_int_t transmit; 980 }; 981 #define PPPIOCSCOMPRESS32 _IOW('t', 77, struct ppp_option_data32) 982 983 static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 984 { 985 struct ppp_file *pf; 986 int err = -ENOIOCTLCMD; 987 void __user *argp = (void __user *)arg; 988 989 mutex_lock(&ppp_mutex); 990 991 pf = file->private_data; 992 if (pf && pf->kind == INTERFACE) { 993 struct ppp *ppp = PF_TO_PPP(pf); 994 switch (cmd) { 995 #ifdef CONFIG_PPP_FILTER 996 case PPPIOCSPASS32: 997 case PPPIOCSACTIVE32: 998 { 999 struct bpf_prog *filter = compat_ppp_get_filter(argp); 1000 struct bpf_prog **which; 1001 1002 if (IS_ERR(filter)) { 1003 err = PTR_ERR(filter); 1004 break; 1005 } 1006 if (cmd == PPPIOCSPASS32) 1007 which = &ppp->pass_filter; 1008 else 1009 which = &ppp->active_filter; 1010 ppp_lock(ppp); 1011 if (*which) 1012 bpf_prog_destroy(*which); 1013 *which = filter; 1014 ppp_unlock(ppp); 1015 err = 0; 1016 break; 1017 } 1018 #endif /* CONFIG_PPP_FILTER */ 1019 case PPPIOCSCOMPRESS32: 1020 { 1021 struct ppp_option_data32 data32; 1022 if (copy_from_user(&data32, argp, sizeof(data32))) { 1023 err = -EFAULT; 1024 } else { 1025 struct ppp_option_data data = { 1026 .ptr = compat_ptr(data32.ptr), 1027 .length = data32.length, 1028 .transmit = data32.transmit 1029 }; 1030 err = ppp_set_compress(ppp, &data); 1031 } 1032 break; 1033 } 1034 } 1035 } 1036 mutex_unlock(&ppp_mutex); 1037 1038 /* all other commands have compatible arguments */ 1039 if (err == -ENOIOCTLCMD) 1040 err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1041 1042 return err; 1043 } 1044 #endif 1045 1046 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, 1047 struct file *file, unsigned int cmd, unsigned long arg) 1048 { 1049 int unit, err = -EFAULT; 1050 struct ppp *ppp; 1051 struct channel *chan; 1052 struct ppp_net *pn; 1053 int __user *p = (int __user *)arg; 1054 1055 if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) 1056 return -EPERM; 1057 1058 switch (cmd) { 1059 case PPPIOCNEWUNIT: 1060 /* Create a new ppp unit */ 1061 if (get_user(unit, p)) 1062 break; 1063 err = ppp_create_interface(net, file, &unit); 1064 if (err < 0) 1065 break; 1066 1067 err = -EFAULT; 1068 if (put_user(unit, p)) 1069 break; 1070 err = 0; 1071 break; 1072 1073 case PPPIOCATTACH: 1074 /* Attach to an existing ppp unit */ 1075 if (get_user(unit, p)) 1076 break; 1077 err = -ENXIO; 1078 pn = ppp_pernet(net); 1079 mutex_lock(&pn->all_ppp_mutex); 1080 ppp = ppp_find_unit(pn, unit); 1081 if (ppp) { 1082 refcount_inc(&ppp->file.refcnt); 1083 file->private_data = &ppp->file; 1084 err = 0; 1085 } 1086 mutex_unlock(&pn->all_ppp_mutex); 1087 break; 1088 1089 case PPPIOCATTCHAN: 1090 if (get_user(unit, p)) 1091 break; 1092 err = -ENXIO; 1093 pn = ppp_pernet(net); 1094 spin_lock_bh(&pn->all_channels_lock); 1095 chan = ppp_find_channel(pn, unit); 1096 if (chan) { 1097 refcount_inc(&chan->file.refcnt); 1098 file->private_data = &chan->file; 1099 err = 0; 1100 } 1101 spin_unlock_bh(&pn->all_channels_lock); 1102 break; 1103 1104 default: 1105 err = -ENOTTY; 1106 } 1107 1108 return err; 1109 } 1110 1111 static const struct file_operations ppp_device_fops = { 1112 .owner = THIS_MODULE, 1113 .read = ppp_read, 1114 .write = ppp_write, 1115 .poll = ppp_poll, 1116 .unlocked_ioctl = ppp_ioctl, 1117 #ifdef CONFIG_COMPAT 1118 .compat_ioctl = ppp_compat_ioctl, 1119 #endif 1120 .open = ppp_open, 1121 .release = ppp_release, 1122 .llseek = noop_llseek, 1123 }; 1124 1125 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head); 1126 1127 static __net_init int ppp_init_net(struct net *net) 1128 { 1129 struct ppp_net *pn = net_generic(net, ppp_net_id); 1130 1131 idr_init(&pn->units_idr); 1132 mutex_init(&pn->all_ppp_mutex); 1133 1134 INIT_LIST_HEAD(&pn->all_channels); 1135 INIT_LIST_HEAD(&pn->new_channels); 1136 1137 spin_lock_init(&pn->all_channels_lock); 1138 1139 return 0; 1140 } 1141 1142 static __net_exit void ppp_exit_rtnl_net(struct net *net, 1143 struct list_head *dev_to_kill) 1144 { 1145 struct ppp_net *pn = net_generic(net, ppp_net_id); 1146 struct ppp *ppp; 1147 int id; 1148 1149 idr_for_each_entry(&pn->units_idr, ppp, id) 1150 ppp_nl_dellink(netdev_from_priv(ppp), dev_to_kill); 1151 } 1152 1153 static __net_exit void ppp_exit_net(struct net *net) 1154 { 1155 struct ppp_net *pn = net_generic(net, ppp_net_id); 1156 1157 mutex_destroy(&pn->all_ppp_mutex); 1158 idr_destroy(&pn->units_idr); 1159 WARN_ON_ONCE(!list_empty(&pn->all_channels)); 1160 WARN_ON_ONCE(!list_empty(&pn->new_channels)); 1161 } 1162 1163 static struct pernet_operations ppp_net_ops = { 1164 .init = ppp_init_net, 1165 .exit_rtnl = ppp_exit_rtnl_net, 1166 .exit = ppp_exit_net, 1167 .id = &ppp_net_id, 1168 .size = sizeof(struct ppp_net), 1169 }; 1170 1171 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set) 1172 { 1173 struct net_device *dev = netdev_from_priv(ppp); 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(dev->name, IFNAMSIZ, "ppp%i", ret); 1186 if (!netdev_name_in_use(ppp->ppp_net, 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(dev->name, IFNAMSIZ, "ppp%i", ppp->file.index); 1215 1216 mutex_unlock(&pn->all_ppp_mutex); 1217 1218 ret = register_netdevice(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->ppp_net = src_net; 1244 ppp->mru = PPP_MRU; 1245 ppp->owner = conf->file; 1246 1247 init_ppp_file(&ppp->file, INTERFACE); 1248 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */ 1249 1250 for (indx = 0; indx < NUM_NP; ++indx) 1251 ppp->npmode[indx] = NPMODE_PASS; 1252 INIT_LIST_HEAD(&ppp->channels); 1253 spin_lock_init(&ppp->rlock); 1254 spin_lock_init(&ppp->wlock); 1255 1256 ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion); 1257 if (!ppp->xmit_recursion) { 1258 err = -ENOMEM; 1259 goto err1; 1260 } 1261 for_each_possible_cpu(cpu) { 1262 struct ppp_xmit_recursion *xmit_recursion; 1263 1264 xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu); 1265 xmit_recursion->owner = NULL; 1266 local_lock_init(&xmit_recursion->bh_lock); 1267 } 1268 1269 #ifdef CONFIG_PPP_MULTILINK 1270 ppp->minseq = -1; 1271 skb_queue_head_init(&ppp->mrq); 1272 #endif /* CONFIG_PPP_MULTILINK */ 1273 #ifdef CONFIG_PPP_FILTER 1274 ppp->pass_filter = NULL; 1275 ppp->active_filter = NULL; 1276 #endif /* CONFIG_PPP_FILTER */ 1277 1278 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set); 1279 if (err < 0) 1280 goto err2; 1281 1282 conf->file->private_data = &ppp->file; 1283 1284 return 0; 1285 err2: 1286 free_percpu(ppp->xmit_recursion); 1287 err1: 1288 return err; 1289 } 1290 1291 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = { 1292 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 }, 1293 }; 1294 1295 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[], 1296 struct netlink_ext_ack *extack) 1297 { 1298 if (!data) 1299 return -EINVAL; 1300 1301 if (!data[IFLA_PPP_DEV_FD]) 1302 return -EINVAL; 1303 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0) 1304 return -EBADF; 1305 1306 return 0; 1307 } 1308 1309 static int ppp_nl_newlink(struct net_device *dev, 1310 struct rtnl_newlink_params *params, 1311 struct netlink_ext_ack *extack) 1312 { 1313 struct net *link_net = rtnl_newlink_link_net(params); 1314 struct nlattr **data = params->data; 1315 struct nlattr **tb = params->tb; 1316 struct ppp_config conf = { 1317 .unit = -1, 1318 .ifname_is_set = true, 1319 }; 1320 struct file *file; 1321 int err; 1322 1323 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD])); 1324 if (!file) 1325 return -EBADF; 1326 1327 /* rtnl_lock is already held here, but ppp_create_interface() locks 1328 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids 1329 * possible deadlock due to lock order inversion, at the cost of 1330 * pushing the problem back to userspace. 1331 */ 1332 if (!mutex_trylock(&ppp_mutex)) { 1333 err = -EBUSY; 1334 goto out; 1335 } 1336 1337 if (file->f_op != &ppp_device_fops || file->private_data) { 1338 err = -EBADF; 1339 goto out_unlock; 1340 } 1341 1342 conf.file = file; 1343 1344 /* Don't use device name generated by the rtnetlink layer when ifname 1345 * isn't specified. Let ppp_dev_configure() set the device name using 1346 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows 1347 * userspace to infer the device name using to the PPPIOCGUNIT ioctl. 1348 */ 1349 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME])) 1350 conf.ifname_is_set = false; 1351 1352 err = ppp_dev_configure(link_net, dev, &conf); 1353 1354 out_unlock: 1355 mutex_unlock(&ppp_mutex); 1356 out: 1357 fput(file); 1358 1359 return err; 1360 } 1361 1362 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head) 1363 { 1364 unregister_netdevice_queue(dev, head); 1365 } 1366 1367 static size_t ppp_nl_get_size(const struct net_device *dev) 1368 { 1369 return 0; 1370 } 1371 1372 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev) 1373 { 1374 return 0; 1375 } 1376 1377 static struct net *ppp_nl_get_link_net(const struct net_device *dev) 1378 { 1379 struct ppp *ppp = netdev_priv(dev); 1380 1381 return READ_ONCE(ppp->ppp_net); 1382 } 1383 1384 static struct rtnl_link_ops ppp_link_ops __read_mostly = { 1385 .kind = "ppp", 1386 .maxtype = IFLA_PPP_MAX, 1387 .policy = ppp_nl_policy, 1388 .priv_size = sizeof(struct ppp), 1389 .setup = ppp_setup, 1390 .validate = ppp_nl_validate, 1391 .newlink = ppp_nl_newlink, 1392 .dellink = ppp_nl_dellink, 1393 .get_size = ppp_nl_get_size, 1394 .fill_info = ppp_nl_fill_info, 1395 .get_link_net = ppp_nl_get_link_net, 1396 }; 1397 1398 #define PPP_MAJOR 108 1399 1400 /* Called at boot time if ppp is compiled into the kernel, 1401 or at module load time (from init_module) if compiled as a module. */ 1402 static int __init ppp_init(void) 1403 { 1404 int err; 1405 1406 pr_info("PPP generic driver version " PPP_VERSION "\n"); 1407 1408 err = register_pernet_device(&ppp_net_ops); 1409 if (err) { 1410 pr_err("failed to register PPP pernet device (%d)\n", err); 1411 goto out; 1412 } 1413 1414 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops); 1415 if (err) { 1416 pr_err("failed to register PPP device (%d)\n", err); 1417 goto out_net; 1418 } 1419 1420 err = class_register(&ppp_class); 1421 if (err) 1422 goto out_chrdev; 1423 1424 err = rtnl_link_register(&ppp_link_ops); 1425 if (err) { 1426 pr_err("failed to register rtnetlink PPP handler\n"); 1427 goto out_class; 1428 } 1429 1430 /* not a big deal if we fail here :-) */ 1431 device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp"); 1432 1433 return 0; 1434 1435 out_class: 1436 class_unregister(&ppp_class); 1437 out_chrdev: 1438 unregister_chrdev(PPP_MAJOR, "ppp"); 1439 out_net: 1440 unregister_pernet_device(&ppp_net_ops); 1441 out: 1442 return err; 1443 } 1444 1445 /* 1446 * Network interface unit routines. 1447 */ 1448 static netdev_tx_t 1449 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev) 1450 { 1451 struct ppp *ppp = netdev_priv(dev); 1452 int npi, proto; 1453 unsigned char *pp; 1454 1455 npi = ethertype_to_npindex(ntohs(skb->protocol)); 1456 if (npi < 0) 1457 goto outf; 1458 1459 /* Drop, accept or reject the packet */ 1460 switch (READ_ONCE(ppp->npmode[npi])) { 1461 case NPMODE_PASS: 1462 break; 1463 case NPMODE_QUEUE: 1464 /* it would be nice to have a way to tell the network 1465 system to queue this one up for later. */ 1466 goto outf; 1467 case NPMODE_DROP: 1468 case NPMODE_ERROR: 1469 goto outf; 1470 } 1471 1472 /* Put the 2-byte PPP protocol number on the front, 1473 making sure there is room for the address and control fields. */ 1474 if (skb_cow_head(skb, PPP_HDRLEN)) 1475 goto outf; 1476 1477 pp = skb_push(skb, 2); 1478 proto = npindex_to_proto[npi]; 1479 put_unaligned_be16(proto, pp); 1480 1481 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev))); 1482 ppp_xmit_process(ppp, skb); 1483 1484 return NETDEV_TX_OK; 1485 1486 outf: 1487 kfree_skb(skb); 1488 DEV_STATS_INC(dev, tx_dropped); 1489 return NETDEV_TX_OK; 1490 } 1491 1492 static int 1493 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr, 1494 void __user *addr, int cmd) 1495 { 1496 struct ppp *ppp = netdev_priv(dev); 1497 int err = -EFAULT; 1498 struct ppp_stats stats; 1499 struct ppp_comp_stats cstats; 1500 char *vers; 1501 1502 switch (cmd) { 1503 case SIOCGPPPSTATS: 1504 ppp_get_stats(ppp, &stats); 1505 if (copy_to_user(addr, &stats, sizeof(stats))) 1506 break; 1507 err = 0; 1508 break; 1509 1510 case SIOCGPPPCSTATS: 1511 memset(&cstats, 0, sizeof(cstats)); 1512 if (ppp->xc_state) 1513 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c); 1514 if (ppp->rc_state) 1515 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d); 1516 if (copy_to_user(addr, &cstats, sizeof(cstats))) 1517 break; 1518 err = 0; 1519 break; 1520 1521 case SIOCGPPPVER: 1522 vers = PPP_VERSION; 1523 if (copy_to_user(addr, vers, strlen(vers) + 1)) 1524 break; 1525 err = 0; 1526 break; 1527 1528 default: 1529 err = -EINVAL; 1530 } 1531 1532 return err; 1533 } 1534 1535 static void 1536 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64) 1537 { 1538 stats64->rx_errors = DEV_STATS_READ(dev, rx_errors); 1539 stats64->tx_errors = DEV_STATS_READ(dev, tx_errors); 1540 stats64->rx_dropped = DEV_STATS_READ(dev, rx_dropped); 1541 stats64->tx_dropped = DEV_STATS_READ(dev, tx_dropped); 1542 stats64->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors); 1543 dev_fetch_sw_netstats(stats64, dev->tstats); 1544 } 1545 1546 static int ppp_dev_init(struct net_device *dev) 1547 { 1548 struct ppp *ppp; 1549 1550 netdev_lockdep_set_classes(dev); 1551 1552 ppp = netdev_priv(dev); 1553 /* Let the netdevice take a reference on the ppp file. This ensures 1554 * that ppp_destroy_interface() won't run before the device gets 1555 * unregistered. 1556 */ 1557 refcount_inc(&ppp->file.refcnt); 1558 1559 return 0; 1560 } 1561 1562 static void ppp_dev_uninit(struct net_device *dev) 1563 { 1564 struct ppp *ppp = netdev_priv(dev); 1565 struct ppp_net *pn = ppp_pernet(ppp->ppp_net); 1566 1567 ppp_lock(ppp); 1568 ppp->closing = 1; 1569 ppp_unlock(ppp); 1570 1571 mutex_lock(&pn->all_ppp_mutex); 1572 unit_put(&pn->units_idr, ppp->file.index); 1573 mutex_unlock(&pn->all_ppp_mutex); 1574 1575 ppp->owner = NULL; 1576 1577 ppp->file.dead = 1; 1578 wake_up_interruptible(&ppp->file.rwait); 1579 } 1580 1581 static void ppp_dev_priv_destructor(struct net_device *dev) 1582 { 1583 struct ppp *ppp; 1584 1585 ppp = netdev_priv(dev); 1586 ppp_release_interface(ppp); 1587 } 1588 1589 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx, 1590 struct net_device_path *path) 1591 { 1592 struct ppp *ppp = netdev_priv(ctx->dev); 1593 struct ppp_channel *chan; 1594 struct channel *pch; 1595 1596 if (ppp->flags & SC_MULTILINK) 1597 return -EOPNOTSUPP; 1598 1599 pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist); 1600 if (!pch) 1601 return -ENODEV; 1602 1603 chan = pch->chan; 1604 if (!chan->ops->fill_forward_path) 1605 return -EOPNOTSUPP; 1606 1607 return chan->ops->fill_forward_path(ctx, path, chan); 1608 } 1609 1610 static const struct net_device_ops ppp_netdev_ops = { 1611 .ndo_init = ppp_dev_init, 1612 .ndo_uninit = ppp_dev_uninit, 1613 .ndo_start_xmit = ppp_start_xmit, 1614 .ndo_siocdevprivate = ppp_net_siocdevprivate, 1615 .ndo_get_stats64 = ppp_get_stats64, 1616 .ndo_fill_forward_path = ppp_fill_forward_path, 1617 }; 1618 1619 static const struct device_type ppp_type = { 1620 .name = "ppp", 1621 }; 1622 1623 static void ppp_setup(struct net_device *dev) 1624 { 1625 dev->netdev_ops = &ppp_netdev_ops; 1626 SET_NETDEV_DEVTYPE(dev, &ppp_type); 1627 1628 dev->lltx = true; 1629 1630 dev->hard_header_len = PPP_HDRLEN; 1631 dev->mtu = PPP_MRU; 1632 dev->addr_len = 0; 1633 dev->tx_queue_len = 3; 1634 dev->type = ARPHRD_PPP; 1635 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 1636 dev->priv_destructor = ppp_dev_priv_destructor; 1637 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS; 1638 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST; 1639 dev->hw_features = dev->features; 1640 netif_keep_dst(dev); 1641 } 1642 1643 /* 1644 * Transmit-side routines. 1645 */ 1646 1647 /* Called to do any work queued up on the transmit side that can now be done */ 1648 static void ppp_xmit_flush(struct ppp *ppp) 1649 { 1650 struct sk_buff *skb; 1651 1652 while ((skb = skb_dequeue(&ppp->file.xq))) { 1653 if (unlikely(!ppp_push(ppp, skb))) { 1654 skb_queue_head(&ppp->file.xq, skb); 1655 return; 1656 } 1657 } 1658 /* If there's no work left to do, tell the core net code that we can 1659 * accept some more. 1660 */ 1661 netif_wake_queue(netdev_from_priv(ppp)); 1662 } 1663 1664 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1665 { 1666 ppp_xmit_lock(ppp); 1667 if (unlikely(ppp->closing)) { 1668 kfree_skb(skb); 1669 goto out; 1670 } 1671 if (unlikely(ppp_prepare_tx_skb(ppp, &skb))) 1672 goto out; 1673 /* Fastpath: No backlog, just send the new skb. */ 1674 if (likely(skb_queue_empty(&ppp->file.xq))) { 1675 if (unlikely(!ppp_push(ppp, skb))) { 1676 skb_queue_tail(&ppp->file.xq, skb); 1677 netif_stop_queue(netdev_from_priv(ppp)); 1678 } 1679 goto out; 1680 } 1681 1682 /* Slowpath: Enqueue the new skb and process backlog */ 1683 skb_queue_tail(&ppp->file.xq, skb); 1684 ppp_xmit_flush(ppp); 1685 out: 1686 ppp_xmit_unlock(ppp); 1687 } 1688 1689 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1690 { 1691 struct ppp_xmit_recursion *xmit_recursion; 1692 1693 local_bh_disable(); 1694 1695 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion); 1696 if (xmit_recursion->owner == current) 1697 goto err; 1698 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock); 1699 xmit_recursion->owner = current; 1700 1701 __ppp_xmit_process(ppp, skb); 1702 1703 xmit_recursion->owner = NULL; 1704 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock); 1705 local_bh_enable(); 1706 1707 return; 1708 1709 err: 1710 local_bh_enable(); 1711 1712 kfree_skb(skb); 1713 1714 if (net_ratelimit()) 1715 netdev_err(netdev_from_priv(ppp), "recursion detected\n"); 1716 } 1717 1718 static inline struct sk_buff * 1719 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) 1720 { 1721 struct net_device *dev = netdev_from_priv(ppp); 1722 struct sk_buff *new_skb; 1723 int len; 1724 int new_skb_size = dev->mtu + 1725 ppp->xcomp->comp_extra + dev->hard_header_len; 1726 int compressor_skb_size = 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(dev, "PPP: no memory (comp pkt)\n"); 1736 return NULL; 1737 } 1738 if (dev->hard_header_len > PPP_HDRLEN) 1739 skb_reserve(new_skb, dev->hard_header_len - PPP_HDRLEN); 1740 1741 /* compressor still expects A/C bytes in hdr */ 1742 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, 1743 new_skb->data, skb->len + 2, 1744 compressor_skb_size); 1745 if (len > 0 && (ppp->flags & SC_CCP_UP)) { 1746 consume_skb(skb); 1747 skb = new_skb; 1748 skb_put(skb, len); 1749 skb_pull(skb, 2); /* pull off A/C bytes */ 1750 } else if (len == 0) { 1751 /* didn't compress, or CCP not up yet */ 1752 consume_skb(new_skb); 1753 new_skb = skb; 1754 } else { 1755 /* 1756 * (len < 0) 1757 * MPPE requires that we do not send unencrypted 1758 * frames. The compressor will return -1 if we 1759 * should drop the frame. We cannot simply test 1760 * the compress_proto because MPPE and MPPC share 1761 * the same number. 1762 */ 1763 if (net_ratelimit()) 1764 netdev_err(dev, "ppp: compressor dropped pkt\n"); 1765 consume_skb(new_skb); 1766 new_skb = NULL; 1767 } 1768 return new_skb; 1769 } 1770 1771 /* 1772 * Compress and prepare to send a frame. 1773 * The caller should have locked the xmit path. 1774 * Returns 1 if the skb was consumed, 0 if it can be passed to ppp_push(). 1775 * @pskb is updated if a compressor is in use. 1776 */ 1777 static int 1778 ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb) 1779 { 1780 struct net_device *dev = netdev_from_priv(ppp); 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 = 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, 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(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 + dev->hard_header_len - 2, 1827 GFP_ATOMIC); 1828 if (!new_skb) { 1829 netdev_err(dev, "PPP: no memory (VJ comp pkt)\n"); 1830 goto drop; 1831 } 1832 skb_reserve(new_skb, 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(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(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 struct net_device *dev = netdev_from_priv(ppp); 1967 int len, totlen; 1968 int i, bits, hdrlen, mtu; 1969 int flen; 1970 int navail, nfree, nzero; 1971 int nbigger; 1972 int totspeed; 1973 int totfree; 1974 unsigned char *p, *q; 1975 struct list_head *list; 1976 struct channel *pch; 1977 struct sk_buff *frag; 1978 struct ppp_channel *chan; 1979 1980 totspeed = 0; /*total bitrate of the bundle*/ 1981 nfree = 0; /* # channels which have no packet already queued */ 1982 navail = 0; /* total # of usable channels (not deregistered) */ 1983 nzero = 0; /* number of channels with zero speed associated*/ 1984 totfree = 0; /*total # of channels available and 1985 *having no queued packets before 1986 *starting the fragmentation*/ 1987 1988 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 1989 i = 0; 1990 list_for_each_entry(pch, &ppp->channels, clist) { 1991 pch->avail = 1; 1992 navail++; 1993 pch->speed = pch->chan->speed; 1994 1995 if (skb_queue_empty(&pch->file.xq) || !pch->had_frag) { 1996 if (pch->speed == 0) 1997 nzero++; 1998 else 1999 totspeed += pch->speed; 2000 2001 pch->avail = 2; 2002 ++nfree; 2003 ++totfree; 2004 } 2005 if (!pch->had_frag && i < ppp->nxchan) 2006 ppp->nxchan = i; 2007 2008 ++i; 2009 } 2010 /* 2011 * Don't start sending this packet unless at least half of 2012 * the channels are free. This gives much better TCP 2013 * performance if we have a lot of channels. 2014 */ 2015 if (nfree == 0 || nfree < navail / 2) 2016 return 0; /* can't take now, leave it in transmit queue */ 2017 2018 /* Do protocol field compression */ 2019 if (skb_linearize(skb)) 2020 goto err_linearize; 2021 p = skb->data; 2022 len = skb->len; 2023 if (*p == 0 && mp_protocol_compress) { 2024 ++p; 2025 --len; 2026 } 2027 2028 totlen = len; 2029 nbigger = len % nfree; 2030 2031 /* skip to the channel after the one we last used 2032 and start at that one */ 2033 list = &ppp->channels; 2034 for (i = 0; i < ppp->nxchan; ++i) { 2035 list = list->next; 2036 if (list == &ppp->channels) { 2037 i = 0; 2038 break; 2039 } 2040 } 2041 2042 /* create a fragment for each channel */ 2043 bits = B; 2044 while (len > 0) { 2045 list = list->next; 2046 if (list == &ppp->channels) { 2047 i = 0; 2048 continue; 2049 } 2050 pch = list_entry(list, struct channel, clist); 2051 ++i; 2052 if (!pch->avail) 2053 continue; 2054 2055 /* 2056 * Skip this channel if it has a fragment pending already and 2057 * we haven't given a fragment to all of the free channels. 2058 */ 2059 if (pch->avail == 1) { 2060 if (nfree > 0) 2061 continue; 2062 } else { 2063 pch->avail = 1; 2064 } 2065 2066 spin_lock(&pch->downl); 2067 /* 2068 *if the channel speed is not set divide 2069 *the packet evenly among the free channels; 2070 *otherwise divide it according to the speed 2071 *of the channel we are going to transmit on 2072 */ 2073 flen = len; 2074 if (nfree > 0) { 2075 if (pch->speed == 0) { 2076 flen = len/nfree; 2077 if (nbigger > 0) { 2078 flen++; 2079 nbigger--; 2080 } 2081 } else { 2082 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) / 2083 ((totspeed*totfree)/pch->speed)) - hdrlen; 2084 if (nbigger > 0) { 2085 flen += ((totfree - nzero)*pch->speed)/totspeed; 2086 nbigger -= ((totfree - nzero)*pch->speed)/ 2087 totspeed; 2088 } 2089 } 2090 nfree--; 2091 } 2092 2093 /* 2094 *check if we are on the last channel or 2095 *we exceded the length of the data to 2096 *fragment 2097 */ 2098 if ((nfree <= 0) || (flen > len)) 2099 flen = len; 2100 /* 2101 *it is not worth to tx on slow channels: 2102 *in that case from the resulting flen according to the 2103 *above formula will be equal or less than zero. 2104 *Skip the channel in this case 2105 */ 2106 if (flen <= 0) { 2107 pch->avail = 2; 2108 spin_unlock(&pch->downl); 2109 continue; 2110 } 2111 2112 /* 2113 * hdrlen includes the 2-byte PPP protocol field, but the 2114 * MTU counts only the payload excluding the protocol field. 2115 * (RFC1661 Section 2) 2116 */ 2117 mtu = pch->chan->mtu - (hdrlen - 2); 2118 if (mtu < 4) 2119 mtu = 4; 2120 if (flen > mtu) 2121 flen = mtu; 2122 if (flen == len) 2123 bits |= E; 2124 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC); 2125 if (!frag) 2126 goto noskb; 2127 q = skb_put(frag, flen + hdrlen); 2128 2129 /* make the MP header */ 2130 put_unaligned_be16(PPP_MP, q); 2131 if (ppp->flags & SC_MP_XSHORTSEQ) { 2132 q[2] = bits + ((ppp->nxseq >> 8) & 0xf); 2133 q[3] = ppp->nxseq; 2134 } else { 2135 q[2] = bits; 2136 q[3] = ppp->nxseq >> 16; 2137 q[4] = ppp->nxseq >> 8; 2138 q[5] = ppp->nxseq; 2139 } 2140 2141 memcpy(q + hdrlen, p, flen); 2142 2143 /* try to send it down the channel */ 2144 chan = pch->chan; 2145 if (!skb_queue_empty(&pch->file.xq) || 2146 !chan->ops->start_xmit(chan, frag)) 2147 skb_queue_tail(&pch->file.xq, frag); 2148 pch->had_frag = 1; 2149 p += flen; 2150 len -= flen; 2151 ++ppp->nxseq; 2152 bits = 0; 2153 spin_unlock(&pch->downl); 2154 } 2155 ppp->nxchan = i; 2156 2157 return 1; 2158 2159 noskb: 2160 spin_unlock(&pch->downl); 2161 err_linearize: 2162 if (READ_ONCE(ppp->debug) & 1) 2163 netdev_err(dev, "PPP: no memory (fragment)\n"); 2164 DEV_STATS_INC(dev, tx_errors); 2165 ++ppp->nxseq; 2166 return 1; /* abandon the frame */ 2167 } 2168 #endif /* CONFIG_PPP_MULTILINK */ 2169 2170 /* Try to send data out on a channel */ 2171 static void __ppp_channel_push(struct channel *pch, struct ppp *ppp) 2172 { 2173 struct sk_buff *skb; 2174 2175 spin_lock(&pch->downl); 2176 if (pch->chan) { 2177 while (!skb_queue_empty(&pch->file.xq)) { 2178 skb = skb_dequeue(&pch->file.xq); 2179 if (!pch->chan->ops->start_xmit(pch->chan, skb)) { 2180 /* put the packet back and try again later */ 2181 skb_queue_head(&pch->file.xq, skb); 2182 break; 2183 } 2184 } 2185 } else { 2186 /* channel got deregistered */ 2187 skb_queue_purge(&pch->file.xq); 2188 } 2189 spin_unlock(&pch->downl); 2190 /* see if there is anything from the attached unit to be sent */ 2191 if (skb_queue_empty(&pch->file.xq)) { 2192 if (ppp) { 2193 ppp_xmit_lock(ppp); 2194 if (!ppp->closing) 2195 ppp_xmit_flush(ppp); 2196 ppp_xmit_unlock(ppp); 2197 } 2198 } 2199 } 2200 2201 static void ppp_channel_push(struct channel *pch) 2202 { 2203 struct ppp_xmit_recursion *xmit_recursion; 2204 struct ppp *ppp; 2205 2206 rcu_read_lock_bh(); 2207 ppp = rcu_dereference_bh(pch->ppp); 2208 if (ppp) { 2209 xmit_recursion = this_cpu_ptr(ppp->xmit_recursion); 2210 local_lock_nested_bh(&ppp->xmit_recursion->bh_lock); 2211 xmit_recursion->owner = current; 2212 __ppp_channel_push(pch, ppp); 2213 xmit_recursion->owner = NULL; 2214 local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock); 2215 } else { 2216 __ppp_channel_push(pch, NULL); 2217 } 2218 rcu_read_unlock_bh(); 2219 } 2220 2221 /* 2222 * Receive-side routines. 2223 */ 2224 2225 struct ppp_mp_skb_parm { 2226 u32 sequence; 2227 u8 BEbits; 2228 }; 2229 #define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb)) 2230 2231 static inline void 2232 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2233 { 2234 ppp_recv_lock(ppp); 2235 if (!ppp->closing) 2236 ppp_receive_frame(ppp, skb, pch); 2237 else 2238 kfree_skb(skb); 2239 ppp_recv_unlock(ppp); 2240 } 2241 2242 /** 2243 * __ppp_decompress_proto - Decompress protocol field, slim version. 2244 * @skb: Socket buffer where protocol field should be decompressed. It must have 2245 * at least 1 byte of head room and 1 byte of linear data. First byte of 2246 * data must be a protocol field byte. 2247 * 2248 * Decompress protocol field in PPP header if it's compressed, e.g. when 2249 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data 2250 * length are done in this function. 2251 */ 2252 static void __ppp_decompress_proto(struct sk_buff *skb) 2253 { 2254 if (ppp_skb_is_compressed_proto(skb)) 2255 *(u8 *)skb_push(skb, 1) = 0x00; 2256 } 2257 2258 /** 2259 * ppp_decompress_proto - Check skb data room and decompress protocol field. 2260 * @skb: Socket buffer where protocol field should be decompressed. First byte 2261 * of data must be a protocol field byte. 2262 * 2263 * Decompress protocol field in PPP header if it's compressed, e.g. when 2264 * Protocol-Field-Compression (PFC) was negotiated. This function also makes 2265 * sure that skb data room is sufficient for Protocol field, before and after 2266 * decompression. 2267 * 2268 * Return: true - decompressed successfully, false - not enough room in skb. 2269 */ 2270 static bool ppp_decompress_proto(struct sk_buff *skb) 2271 { 2272 /* At least one byte should be present (if protocol is compressed) */ 2273 if (!pskb_may_pull(skb, 1)) 2274 return false; 2275 2276 __ppp_decompress_proto(skb); 2277 2278 /* Protocol field should occupy 2 bytes when not compressed */ 2279 return pskb_may_pull(skb, 2); 2280 } 2281 2282 #define PPP_BRIDGE_GSO_TYPES (SKB_GSO_TCPV4 | SKB_GSO_TCPV6 | \ 2283 SKB_GSO_TCP_ECN | SKB_GSO_TCP_ACCECN | \ 2284 SKB_GSO_TCP_FIXEDID | SKB_GSO_UDP_L4 | \ 2285 SKB_GSO_FRAGLIST | SKB_GSO_DODGY) 2286 2287 /* Segment a GSO packet (built by PPPoE GRO, or injected with a 2288 * virtio_net_hdr) before sending it to a bridged channel that does 2289 * not accept GSO packets. 2290 * skb->data points to the PPP protocol field, which is replicated 2291 * in front of each segment. 2292 * Returns a list of segments, or NULL if the packet was dropped. 2293 */ 2294 static struct sk_buff *ppp_bridge_gso_segment(struct sk_buff *skb, 2295 netdev_features_t features) 2296 { 2297 struct sk_buff *segs; 2298 2299 /* skb->dev is NULL here (cleared by __sk_receive_skb() for PPPoE), 2300 * and some GSO handlers (tunnels, IPv6 UFO) dereference it. 2301 */ 2302 if (skb->encapsulation || 2303 (skb_shinfo(skb)->gso_type & ~PPP_BRIDGE_GSO_TYPES)) 2304 goto drop; 2305 2306 if (!pskb_may_pull(skb, PPP_PROTO_LEN)) 2307 goto drop; 2308 2309 switch (get_unaligned((__be16 *)skb->data)) { 2310 case htons(PPP_IP): 2311 skb->protocol = htons(ETH_P_IP); 2312 break; 2313 case htons(PPP_IPV6): 2314 skb->protocol = htons(ETH_P_IPV6); 2315 break; 2316 default: 2317 goto drop; 2318 } 2319 skb_set_network_header(skb, PPP_PROTO_LEN); 2320 2321 /* No checksum offload: skb_segment() computes the checksums. */ 2322 segs = skb_gso_segment(skb, features); 2323 if (IS_ERR_OR_NULL(segs)) 2324 goto drop; 2325 2326 consume_skb(skb); 2327 return segs; 2328 2329 drop: 2330 kfree_skb(skb); 2331 return NULL; 2332 } 2333 2334 static void ppp_bridge_xmit(struct ppp_channel *chan, struct sk_buff *skb) 2335 { 2336 if (!chan->direct_xmit && skb_linearize(skb)) 2337 goto drop; 2338 2339 if (!chan->xmit_offload && skb->ip_summed == CHECKSUM_PARTIAL && 2340 skb_csum_hwoffload_help(skb, 0)) 2341 goto drop; 2342 2343 if (chan->ops->start_xmit(chan, skb)) 2344 return; 2345 drop: 2346 kfree_skb(skb); 2347 } 2348 2349 /* Attempt to handle a frame via. a bridged channel, if one exists. 2350 * If the channel is bridged, the frame is consumed by the bridge. 2351 * If not, the caller must handle the frame by normal recv mechanisms. 2352 * Returns true if the frame is consumed, false otherwise. 2353 */ 2354 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb) 2355 { 2356 struct sk_buff *segs, *next; 2357 struct ppp_channel *chan; 2358 struct channel *pchb; 2359 2360 rcu_read_lock(); 2361 pchb = rcu_dereference(pch->bridge); 2362 if (!pchb) 2363 goto out_rcu; 2364 2365 spin_lock_bh(&pchb->downl); 2366 if (!pchb->chan) { 2367 /* channel got unregistered */ 2368 kfree_skb(skb); 2369 goto outl; 2370 } 2371 2372 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net)); 2373 2374 /* Receive paths such as L2TP pull headers without updating 2375 * the checksum state: drop a stale CHECKSUM_PARTIAL state 2376 * pointing before skb->data, as skb_postpull_rcsum() does. 2377 */ 2378 if (skb->ip_summed == CHECKSUM_PARTIAL && 2379 skb_checksum_start_offset(skb) < 0) 2380 skb->ip_summed = CHECKSUM_NONE; 2381 2382 chan = pchb->chan; 2383 if (!chan->xmit_offload && skb_is_gso(skb)) { 2384 /* Channels needing linear packets get linear segments, 2385 * others keep references to the original pages. 2386 */ 2387 segs = ppp_bridge_gso_segment(skb, chan->direct_xmit ? 2388 NETIF_F_SG : 0); 2389 skb_list_walk_safe(segs, skb, next) { 2390 skb_mark_not_on_list(skb); 2391 ppp_bridge_xmit(chan, skb); 2392 } 2393 } else { 2394 ppp_bridge_xmit(chan, skb); 2395 } 2396 2397 outl: 2398 spin_unlock_bh(&pchb->downl); 2399 out_rcu: 2400 rcu_read_unlock(); 2401 2402 /* If pchb is set then we've consumed the packet */ 2403 return !!pchb; 2404 } 2405 2406 void 2407 ppp_input(struct ppp_channel *chan, struct sk_buff *skb) 2408 { 2409 struct channel *pch = chan->ppp; 2410 struct ppp *ppp; 2411 int proto; 2412 2413 if (!pch) { 2414 kfree_skb(skb); 2415 return; 2416 } 2417 2418 /* If the channel is bridged, transmit via. bridge */ 2419 if (ppp_channel_bridge_input(pch, skb)) 2420 return; 2421 2422 rcu_read_lock_bh(); 2423 ppp = rcu_dereference_bh(pch->ppp); 2424 if (!ppp_decompress_proto(skb)) { 2425 kfree_skb(skb); 2426 if (ppp) { 2427 DEV_STATS_INC(netdev_from_priv(ppp), rx_length_errors); 2428 ppp_receive_error(ppp); 2429 } 2430 goto done; 2431 } 2432 2433 proto = PPP_PROTO(skb); 2434 if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) { 2435 /* put it on the channel queue */ 2436 skb_queue_tail(&pch->file.rq, skb); 2437 /* drop old frames if queue too long */ 2438 while (pch->file.rq.qlen > PPP_MAX_RQLEN && 2439 (skb = skb_dequeue(&pch->file.rq))) 2440 kfree_skb(skb); 2441 wake_up_interruptible(&pch->file.rwait); 2442 } else { 2443 ppp_do_recv(ppp, skb, pch); 2444 } 2445 2446 done: 2447 rcu_read_unlock_bh(); 2448 } 2449 2450 void 2451 ppp_input_error(struct ppp_channel *chan) 2452 { 2453 struct channel *pch = chan->ppp; 2454 struct ppp *ppp; 2455 2456 if (!pch) 2457 return; 2458 2459 rcu_read_lock_bh(); 2460 ppp = rcu_dereference_bh(pch->ppp); 2461 if (ppp) { 2462 ppp_recv_lock(ppp); 2463 ppp_receive_error(ppp); 2464 ppp_recv_unlock(ppp); 2465 } 2466 rcu_read_unlock_bh(); 2467 } 2468 2469 /* 2470 * We come in here to process a received frame. 2471 * The receive side of the ppp unit is locked. 2472 */ 2473 static void 2474 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2475 { 2476 skb_checksum_complete_unset(skb); 2477 #ifdef CONFIG_PPP_MULTILINK 2478 /* XXX do channel-level decompression here */ 2479 if (PPP_PROTO(skb) == PPP_MP) 2480 ppp_receive_mp_frame(ppp, skb, pch); 2481 else 2482 #endif /* CONFIG_PPP_MULTILINK */ 2483 ppp_receive_nonmp_frame(ppp, skb); 2484 } 2485 2486 static void 2487 ppp_receive_error(struct ppp *ppp) 2488 { 2489 DEV_STATS_INC(netdev_from_priv(ppp), rx_errors); 2490 if (ppp->vj) 2491 slhc_toss(ppp->vj); 2492 } 2493 2494 static void 2495 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb) 2496 { 2497 struct net_device *dev = netdev_from_priv(ppp); 2498 struct sk_buff *ns; 2499 int proto, len, npi; 2500 2501 /* 2502 * Decompress the frame, if compressed. 2503 * Note that some decompressors need to see uncompressed frames 2504 * that come in as well as compressed frames. 2505 */ 2506 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) && 2507 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0) 2508 skb = ppp_decompress_frame(ppp, skb); 2509 2510 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR) 2511 goto err; 2512 2513 /* At this point the "Protocol" field MUST be decompressed, either in 2514 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame(). 2515 */ 2516 proto = PPP_PROTO(skb); 2517 switch (proto) { 2518 case PPP_VJC_COMP: 2519 /* decompress VJ compressed packets */ 2520 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2521 goto err; 2522 2523 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) { 2524 /* copy to a new sk_buff with more tailroom */ 2525 ns = dev_alloc_skb(skb->len + 128); 2526 if (!ns) { 2527 netdev_err(dev, "PPP: no memory (VJ decomp)\n"); 2528 goto err; 2529 } 2530 skb_reserve(ns, 2); 2531 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); 2532 consume_skb(skb); 2533 skb = ns; 2534 } 2535 else 2536 skb->ip_summed = CHECKSUM_NONE; 2537 2538 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2); 2539 if (len <= 0) { 2540 netdev_printk(KERN_DEBUG, dev, 2541 "PPP: VJ decompression error\n"); 2542 goto err; 2543 } 2544 len += 2; 2545 if (len > skb->len) 2546 skb_put(skb, len - skb->len); 2547 else if (len < skb->len) 2548 skb_trim(skb, len); 2549 proto = PPP_IP; 2550 break; 2551 2552 case PPP_VJC_UNCOMP: 2553 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2554 goto err; 2555 2556 /* Until we fix the decompressor need to make sure 2557 * data portion is linear. 2558 */ 2559 if (!pskb_may_pull(skb, skb->len)) 2560 goto err; 2561 2562 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) { 2563 netdev_err(dev, "PPP: VJ uncompressed error\n"); 2564 goto err; 2565 } 2566 proto = PPP_IP; 2567 break; 2568 2569 case PPP_CCP: 2570 ppp_ccp_peek(ppp, skb, 1); 2571 break; 2572 } 2573 2574 dev_sw_netstats_rx_add(dev, skb->len - PPP_PROTO_LEN); 2575 2576 npi = proto_to_npindex(proto); 2577 if (npi < 0) { 2578 /* control or unknown frame - pass it to pppd */ 2579 skb_queue_tail(&ppp->file.rq, skb); 2580 /* limit queue length by dropping old frames */ 2581 while (ppp->file.rq.qlen > PPP_MAX_RQLEN && 2582 (skb = skb_dequeue(&ppp->file.rq))) 2583 kfree_skb(skb); 2584 /* wake up any process polling or blocking on read */ 2585 wake_up_interruptible(&ppp->file.rwait); 2586 2587 } else { 2588 /* network protocol frame - give it to the kernel */ 2589 2590 #ifdef CONFIG_PPP_FILTER 2591 if (ppp->pass_filter || ppp->active_filter) { 2592 if (skb_unclone(skb, GFP_ATOMIC)) 2593 goto err; 2594 /* Check if the packet passes the pass and active filters. 2595 * See comment for PPP_FILTER_INBOUND_TAG above. 2596 */ 2597 *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG); 2598 if (ppp->pass_filter && 2599 bpf_prog_run(ppp->pass_filter, skb) == 0) { 2600 if (READ_ONCE(ppp->debug) & 1) 2601 netdev_printk(KERN_DEBUG, dev, 2602 "PPP: inbound frame " 2603 "not passed\n"); 2604 kfree_skb(skb); 2605 return; 2606 } 2607 if (!(ppp->active_filter && 2608 bpf_prog_run(ppp->active_filter, skb) == 0)) 2609 WRITE_ONCE(ppp->last_recv, jiffies); 2610 __skb_pull(skb, 2); 2611 } else 2612 #endif /* CONFIG_PPP_FILTER */ 2613 WRITE_ONCE(ppp->last_recv, jiffies); 2614 2615 if ((dev->flags & IFF_UP) == 0 || 2616 READ_ONCE(ppp->npmode[npi]) != NPMODE_PASS) { 2617 kfree_skb(skb); 2618 } else { 2619 /* chop off protocol */ 2620 skb_pull_rcsum(skb, 2); 2621 skb->dev = dev; 2622 skb->protocol = htons(npindex_to_ethertype[npi]); 2623 skb_reset_mac_header(skb); 2624 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, 2625 dev_net(dev))); 2626 netif_rx(skb); 2627 } 2628 } 2629 return; 2630 2631 err: 2632 kfree_skb(skb); 2633 ppp_receive_error(ppp); 2634 } 2635 2636 static struct sk_buff * 2637 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb) 2638 { 2639 int proto = PPP_PROTO(skb); 2640 struct sk_buff *ns; 2641 int len; 2642 2643 /* Until we fix all the decompressor's need to make sure 2644 * data portion is linear. 2645 */ 2646 if (!pskb_may_pull(skb, skb->len)) 2647 goto err; 2648 2649 if (proto == PPP_COMP) { 2650 int obuff_size; 2651 2652 switch(ppp->rcomp->compress_proto) { 2653 case CI_MPPE: 2654 obuff_size = ppp->mru + PPP_HDRLEN + 1; 2655 break; 2656 default: 2657 obuff_size = ppp->mru + PPP_HDRLEN; 2658 break; 2659 } 2660 2661 ns = dev_alloc_skb(obuff_size); 2662 if (!ns) { 2663 netdev_err(netdev_from_priv(ppp), 2664 "ppp_decompress_frame: no memory\n"); 2665 goto err; 2666 } 2667 /* the decompressor still expects the A/C bytes in the hdr */ 2668 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2, 2669 skb->len + 2, ns->data, obuff_size); 2670 if (len < 0) { 2671 /* Pass the compressed frame to pppd as an 2672 error indication. */ 2673 if (len == DECOMP_FATALERROR) 2674 ppp->rstate |= SC_DC_FERROR; 2675 kfree_skb(ns); 2676 goto err; 2677 } 2678 2679 consume_skb(skb); 2680 skb = ns; 2681 skb_put(skb, len); 2682 skb_pull(skb, 2); /* pull off the A/C bytes */ 2683 2684 /* Don't call __ppp_decompress_proto() here, but instead rely on 2685 * corresponding algo (mppe/bsd/deflate) to decompress it. 2686 */ 2687 } else { 2688 /* Uncompressed frame - pass to decompressor so it 2689 can update its dictionary if necessary. */ 2690 if (ppp->rcomp->incomp) 2691 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2, 2692 skb->len + 2); 2693 } 2694 2695 return skb; 2696 2697 err: 2698 ppp->rstate |= SC_DC_ERROR; 2699 ppp_receive_error(ppp); 2700 return skb; 2701 } 2702 2703 #ifdef CONFIG_PPP_MULTILINK 2704 /* 2705 * Receive a multilink frame. 2706 * We put it on the reconstruction queue and then pull off 2707 * as many completed frames as we can. 2708 */ 2709 static void 2710 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2711 { 2712 struct net_device *dev = netdev_from_priv(ppp); 2713 u32 mask, seq; 2714 struct channel *ch; 2715 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 2716 2717 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0) 2718 goto err; /* no good, throw it away */ 2719 2720 /* Decode sequence number and begin/end bits */ 2721 if (ppp->flags & SC_MP_SHORTSEQ) { 2722 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3]; 2723 mask = 0xfff; 2724 } else { 2725 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5]; 2726 mask = 0xffffff; 2727 } 2728 PPP_MP_CB(skb)->BEbits = skb->data[2]; 2729 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */ 2730 2731 /* 2732 * Do protocol ID decompression on the first fragment of each packet. 2733 * We have to do that here, because ppp_receive_nonmp_frame() expects 2734 * decompressed protocol field. 2735 */ 2736 if (PPP_MP_CB(skb)->BEbits & B) 2737 __ppp_decompress_proto(skb); 2738 2739 /* 2740 * Expand sequence number to 32 bits, making it as close 2741 * as possible to ppp->minseq. 2742 */ 2743 seq |= ppp->minseq & ~mask; 2744 if ((int)(ppp->minseq - seq) > (int)(mask >> 1)) 2745 seq += mask + 1; 2746 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1)) 2747 seq -= mask + 1; /* should never happen */ 2748 PPP_MP_CB(skb)->sequence = seq; 2749 pch->lastseq = seq; 2750 2751 /* 2752 * If this packet comes before the next one we were expecting, 2753 * drop it. 2754 */ 2755 if (seq_before(seq, ppp->nextseq)) { 2756 kfree_skb(skb); 2757 DEV_STATS_INC(dev, rx_dropped); 2758 ppp_receive_error(ppp); 2759 return; 2760 } 2761 2762 /* 2763 * Reevaluate minseq, the minimum over all channels of the 2764 * last sequence number received on each channel. Because of 2765 * the increasing sequence number rule, we know that any fragment 2766 * before `minseq' which hasn't arrived is never going to arrive. 2767 * The list of channels can't change because we have the receive 2768 * side of the ppp unit locked. 2769 */ 2770 list_for_each_entry(ch, &ppp->channels, clist) { 2771 if (seq_before(ch->lastseq, seq)) 2772 seq = ch->lastseq; 2773 } 2774 if (seq_before(ppp->minseq, seq)) 2775 ppp->minseq = seq; 2776 2777 /* Put the fragment on the reconstruction queue */ 2778 ppp_mp_insert(ppp, skb); 2779 2780 /* If the queue is getting long, don't wait any longer for packets 2781 before the start of the queue. */ 2782 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) { 2783 struct sk_buff *mskb = skb_peek(&ppp->mrq); 2784 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence)) 2785 ppp->minseq = PPP_MP_CB(mskb)->sequence; 2786 } 2787 2788 /* Pull completed packets off the queue and receive them. */ 2789 while ((skb = ppp_mp_reconstruct(ppp))) { 2790 if (pskb_may_pull(skb, 2)) 2791 ppp_receive_nonmp_frame(ppp, skb); 2792 else { 2793 DEV_STATS_INC(dev, rx_length_errors); 2794 kfree_skb(skb); 2795 ppp_receive_error(ppp); 2796 } 2797 } 2798 2799 return; 2800 2801 err: 2802 kfree_skb(skb); 2803 ppp_receive_error(ppp); 2804 } 2805 2806 /* 2807 * Insert a fragment on the MP reconstruction queue. 2808 * The queue is ordered by increasing sequence number. 2809 */ 2810 static void 2811 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb) 2812 { 2813 struct sk_buff *p; 2814 struct sk_buff_head *list = &ppp->mrq; 2815 u32 seq = PPP_MP_CB(skb)->sequence; 2816 2817 /* N.B. we don't need to lock the list lock because we have the 2818 ppp unit receive-side lock. */ 2819 skb_queue_walk(list, p) { 2820 if (seq_before(seq, PPP_MP_CB(p)->sequence)) 2821 break; 2822 } 2823 __skb_queue_before(list, p, skb); 2824 } 2825 2826 /* 2827 * Reconstruct a packet from the MP fragment queue. 2828 * We go through increasing sequence numbers until we find a 2829 * complete packet, or we get to the sequence number for a fragment 2830 * which hasn't arrived but might still do so. 2831 */ 2832 static struct sk_buff * 2833 ppp_mp_reconstruct(struct ppp *ppp) 2834 { 2835 struct net_device *dev = netdev_from_priv(ppp); 2836 u32 seq = ppp->nextseq; 2837 u32 minseq = ppp->minseq; 2838 struct sk_buff_head *list = &ppp->mrq; 2839 struct sk_buff *p, *tmp; 2840 struct sk_buff *head, *tail; 2841 struct sk_buff *skb = NULL; 2842 int lost = 0, len = 0; 2843 2844 if (ppp->mrru == 0) /* do nothing until mrru is set */ 2845 return NULL; 2846 head = __skb_peek(list); 2847 tail = NULL; 2848 skb_queue_walk_safe(list, p, tmp) { 2849 again: 2850 if (seq_before(PPP_MP_CB(p)->sequence, seq)) { 2851 /* this can't happen, anyway ignore the skb */ 2852 netdev_err(dev, "ppp_mp_reconstruct bad seq %u < %u\n", 2853 PPP_MP_CB(p)->sequence, seq); 2854 __skb_unlink(p, list); 2855 kfree_skb(p); 2856 continue; 2857 } 2858 if (PPP_MP_CB(p)->sequence != seq) { 2859 u32 oldseq; 2860 /* Fragment `seq' is missing. If it is after 2861 minseq, it might arrive later, so stop here. */ 2862 if (seq_after(seq, minseq)) 2863 break; 2864 /* Fragment `seq' is lost, keep going. */ 2865 lost = 1; 2866 oldseq = seq; 2867 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)? 2868 minseq + 1: PPP_MP_CB(p)->sequence; 2869 2870 if (READ_ONCE(ppp->debug) & 1) 2871 netdev_printk(KERN_DEBUG, dev, 2872 "lost frag %u..%u\n", 2873 oldseq, seq-1); 2874 2875 goto again; 2876 } 2877 2878 /* 2879 * At this point we know that all the fragments from 2880 * ppp->nextseq to seq are either present or lost. 2881 * Also, there are no complete packets in the queue 2882 * that have no missing fragments and end before this 2883 * fragment. 2884 */ 2885 2886 /* B bit set indicates this fragment starts a packet */ 2887 if (PPP_MP_CB(p)->BEbits & B) { 2888 head = p; 2889 lost = 0; 2890 len = 0; 2891 } 2892 2893 len += p->len; 2894 2895 /* Got a complete packet yet? */ 2896 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) && 2897 (PPP_MP_CB(head)->BEbits & B)) { 2898 if (len > ppp->mrru + 2) { 2899 DEV_STATS_INC(dev, rx_length_errors); 2900 netdev_printk(KERN_DEBUG, dev, 2901 "PPP: reconstructed packet" 2902 " is too long (%d)\n", len); 2903 } else { 2904 tail = p; 2905 break; 2906 } 2907 ppp->nextseq = seq + 1; 2908 } 2909 2910 /* 2911 * If this is the ending fragment of a packet, 2912 * and we haven't found a complete valid packet yet, 2913 * we can discard up to and including this fragment. 2914 */ 2915 if (PPP_MP_CB(p)->BEbits & E) { 2916 struct sk_buff *tmp2; 2917 2918 skb_queue_reverse_walk_from_safe(list, p, tmp2) { 2919 if (READ_ONCE(ppp->debug) & 1) 2920 netdev_printk(KERN_DEBUG, dev, 2921 "discarding frag %u\n", 2922 PPP_MP_CB(p)->sequence); 2923 __skb_unlink(p, list); 2924 kfree_skb(p); 2925 } 2926 head = skb_peek(list); 2927 if (!head) 2928 break; 2929 } 2930 ++seq; 2931 } 2932 2933 /* If we have a complete packet, copy it all into one skb. */ 2934 if (tail != NULL) { 2935 /* If we have discarded any fragments, 2936 signal a receive error. */ 2937 if (PPP_MP_CB(head)->sequence != ppp->nextseq) { 2938 skb_queue_walk_safe(list, p, tmp) { 2939 if (p == head) 2940 break; 2941 if (READ_ONCE(ppp->debug) & 1) 2942 netdev_printk(KERN_DEBUG, dev, 2943 "discarding frag %u\n", 2944 PPP_MP_CB(p)->sequence); 2945 __skb_unlink(p, list); 2946 kfree_skb(p); 2947 } 2948 2949 if (READ_ONCE(ppp->debug) & 1) 2950 netdev_printk(KERN_DEBUG, dev, 2951 " missed pkts %u..%u\n", 2952 ppp->nextseq, 2953 PPP_MP_CB(head)->sequence-1); 2954 DEV_STATS_INC(dev, rx_dropped); 2955 ppp_receive_error(ppp); 2956 } 2957 2958 skb = head; 2959 if (head != tail) { 2960 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list; 2961 p = skb_queue_next(list, head); 2962 __skb_unlink(skb, list); 2963 skb_queue_walk_from_safe(list, p, tmp) { 2964 __skb_unlink(p, list); 2965 *fragpp = p; 2966 p->next = NULL; 2967 fragpp = &p->next; 2968 2969 skb->len += p->len; 2970 skb->data_len += p->len; 2971 skb->truesize += p->truesize; 2972 2973 if (p == tail) 2974 break; 2975 } 2976 } else { 2977 __skb_unlink(skb, list); 2978 } 2979 2980 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1; 2981 } 2982 2983 return skb; 2984 } 2985 #endif /* CONFIG_PPP_MULTILINK */ 2986 2987 /* 2988 * Channel interface. 2989 */ 2990 2991 /* Create a new, unattached ppp channel. */ 2992 int ppp_register_channel(struct ppp_channel *chan) 2993 { 2994 return ppp_register_net_channel(current->nsproxy->net_ns, chan); 2995 } 2996 2997 /* Create a new, unattached ppp channel for specified net. */ 2998 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan) 2999 { 3000 struct channel *pch; 3001 struct ppp_net *pn; 3002 3003 pch = kzalloc_obj(struct channel); 3004 if (!pch) 3005 return -ENOMEM; 3006 3007 pn = ppp_pernet(net); 3008 3009 pch->chan = chan; 3010 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL); 3011 chan->ppp = pch; 3012 init_ppp_file(&pch->file, CHANNEL); 3013 pch->file.hdrlen = chan->hdrlen; 3014 #ifdef CONFIG_PPP_MULTILINK 3015 pch->lastseq = -1; 3016 #endif /* CONFIG_PPP_MULTILINK */ 3017 mutex_init(&pch->chan_sem); 3018 spin_lock_init(&pch->downl); 3019 spin_lock_init(&pch->upl); 3020 3021 spin_lock_bh(&pn->all_channels_lock); 3022 pch->file.index = ++pn->last_channel_index; 3023 list_add(&pch->list, &pn->new_channels); 3024 atomic_inc(&channel_count); 3025 spin_unlock_bh(&pn->all_channels_lock); 3026 3027 return 0; 3028 } 3029 3030 /* 3031 * Return the index of a channel. 3032 */ 3033 int ppp_channel_index(struct ppp_channel *chan) 3034 { 3035 struct channel *pch = chan->ppp; 3036 3037 if (pch) 3038 return pch->file.index; 3039 return -1; 3040 } 3041 3042 /* 3043 * Return the PPP unit number to which a channel is connected. 3044 */ 3045 int ppp_unit_number(struct ppp_channel *chan) 3046 { 3047 struct channel *pch = chan->ppp; 3048 struct ppp *ppp; 3049 int unit = -1; 3050 3051 if (pch) { 3052 rcu_read_lock(); 3053 ppp = rcu_dereference(pch->ppp); 3054 if (ppp) 3055 unit = ppp->file.index; 3056 rcu_read_unlock(); 3057 } 3058 return unit; 3059 } 3060 3061 /* 3062 * Return the PPP device interface name of a channel. 3063 * Caller must hold RCU read lock. 3064 */ 3065 char *ppp_dev_name(struct ppp_channel *chan) 3066 { 3067 struct channel *pch = chan->ppp; 3068 char *name = NULL; 3069 struct ppp *ppp; 3070 3071 if (pch) { 3072 ppp = rcu_dereference(pch->ppp); 3073 if (ppp) 3074 name = netdev_from_priv(ppp)->name; 3075 } 3076 return name; 3077 } 3078 3079 3080 /* 3081 * Disconnect a channel from the generic layer. 3082 * This must be called in process context. 3083 */ 3084 void 3085 ppp_unregister_channel(struct ppp_channel *chan) 3086 { 3087 struct channel *pch = chan->ppp; 3088 struct ppp_net *pn; 3089 3090 if (!pch) 3091 return; /* should never happen */ 3092 3093 chan->ppp = NULL; 3094 3095 /* 3096 * This ensures that we have returned from any calls into 3097 * the channel's start_xmit or ioctl routine before we proceed. 3098 */ 3099 ppp_disconnect_channel(pch); 3100 mutex_lock(&pch->chan_sem); 3101 spin_lock_bh(&pch->downl); 3102 pch->chan = NULL; 3103 spin_unlock_bh(&pch->downl); 3104 mutex_unlock(&pch->chan_sem); 3105 3106 pn = ppp_pernet(pch->chan_net); 3107 spin_lock_bh(&pn->all_channels_lock); 3108 list_del(&pch->list); 3109 spin_unlock_bh(&pn->all_channels_lock); 3110 3111 ppp_unbridge_channels(pch); 3112 3113 pch->file.dead = 1; 3114 wake_up_interruptible(&pch->file.rwait); 3115 3116 ppp_release_channel(pch); 3117 } 3118 3119 /* 3120 * Callback from a channel when it can accept more to transmit. 3121 * This should be called at BH/softirq level, not interrupt level. 3122 */ 3123 void 3124 ppp_output_wakeup(struct ppp_channel *chan) 3125 { 3126 struct channel *pch = chan->ppp; 3127 3128 if (!pch) 3129 return; 3130 ppp_channel_push(pch); 3131 } 3132 3133 /* 3134 * Compression control. 3135 */ 3136 3137 /* Process the PPPIOCSCOMPRESS ioctl. */ 3138 static int 3139 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data) 3140 { 3141 int err = -EFAULT; 3142 struct compressor *cp, *ocomp; 3143 void *state, *ostate; 3144 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH]; 3145 3146 if (data->length > CCP_MAX_OPTION_LENGTH) 3147 goto out; 3148 if (copy_from_user(ccp_option, data->ptr, data->length)) 3149 goto out; 3150 3151 err = -EINVAL; 3152 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length) 3153 goto out; 3154 3155 cp = try_then_request_module( 3156 find_compressor(ccp_option[0]), 3157 "ppp-compress-%d", ccp_option[0]); 3158 if (!cp) 3159 goto out; 3160 3161 err = -ENOBUFS; 3162 if (data->transmit) { 3163 state = cp->comp_alloc(ccp_option, data->length); 3164 if (state) { 3165 ppp_xmit_lock(ppp); 3166 ppp->xstate &= ~SC_COMP_RUN; 3167 ocomp = ppp->xcomp; 3168 ostate = ppp->xc_state; 3169 ppp->xcomp = cp; 3170 ppp->xc_state = state; 3171 ppp_xmit_unlock(ppp); 3172 if (ostate) { 3173 ocomp->comp_free(ostate); 3174 module_put(ocomp->owner); 3175 } 3176 err = 0; 3177 } else 3178 module_put(cp->owner); 3179 3180 } else { 3181 state = cp->decomp_alloc(ccp_option, data->length); 3182 if (state) { 3183 ppp_recv_lock(ppp); 3184 ppp->rstate &= ~SC_DECOMP_RUN; 3185 ocomp = ppp->rcomp; 3186 ostate = ppp->rc_state; 3187 ppp->rcomp = cp; 3188 ppp->rc_state = state; 3189 ppp_recv_unlock(ppp); 3190 if (ostate) { 3191 ocomp->decomp_free(ostate); 3192 module_put(ocomp->owner); 3193 } 3194 err = 0; 3195 } else 3196 module_put(cp->owner); 3197 } 3198 3199 out: 3200 return err; 3201 } 3202 3203 /* 3204 * Look at a CCP packet and update our state accordingly. 3205 * We assume the caller has the xmit or recv path locked. 3206 */ 3207 static void 3208 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound) 3209 { 3210 unsigned char *dp; 3211 int len; 3212 3213 if (!pskb_may_pull(skb, CCP_HDRLEN + 2)) 3214 return; /* no header */ 3215 dp = skb->data + 2; 3216 3217 switch (CCP_CODE(dp)) { 3218 case CCP_CONFREQ: 3219 3220 /* A ConfReq starts negotiation of compression 3221 * in one direction of transmission, 3222 * and hence brings it down...but which way? 3223 * 3224 * Remember: 3225 * A ConfReq indicates what the sender would like to receive 3226 */ 3227 if(inbound) 3228 /* He is proposing what I should send */ 3229 ppp->xstate &= ~SC_COMP_RUN; 3230 else 3231 /* I am proposing to what he should send */ 3232 ppp->rstate &= ~SC_DECOMP_RUN; 3233 3234 break; 3235 3236 case CCP_TERMREQ: 3237 case CCP_TERMACK: 3238 /* 3239 * CCP is going down, both directions of transmission 3240 */ 3241 ppp->rstate &= ~SC_DECOMP_RUN; 3242 ppp->xstate &= ~SC_COMP_RUN; 3243 break; 3244 3245 case CCP_CONFACK: 3246 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN) 3247 break; 3248 len = CCP_LENGTH(dp); 3249 if (!pskb_may_pull(skb, len + 2)) 3250 return; /* too short */ 3251 dp = skb->data + 2; 3252 dp += CCP_HDRLEN; 3253 len -= CCP_HDRLEN; 3254 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp)) 3255 break; 3256 if (inbound) { 3257 /* we will start receiving compressed packets */ 3258 if (!ppp->rc_state) 3259 break; 3260 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len, 3261 ppp->file.index, 0, ppp->mru, 3262 READ_ONCE(ppp->debug))) { 3263 ppp->rstate |= SC_DECOMP_RUN; 3264 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR); 3265 } 3266 } else { 3267 /* we will soon start sending compressed packets */ 3268 if (!ppp->xc_state) 3269 break; 3270 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len, 3271 ppp->file.index, 0, 3272 READ_ONCE(ppp->debug))) 3273 ppp->xstate |= SC_COMP_RUN; 3274 } 3275 break; 3276 3277 case CCP_RESETACK: 3278 /* reset the [de]compressor */ 3279 if ((ppp->flags & SC_CCP_UP) == 0) 3280 break; 3281 if (inbound) { 3282 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) { 3283 ppp->rcomp->decomp_reset(ppp->rc_state); 3284 ppp->rstate &= ~SC_DC_ERROR; 3285 } 3286 } else { 3287 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN)) 3288 ppp->xcomp->comp_reset(ppp->xc_state); 3289 } 3290 break; 3291 } 3292 } 3293 3294 /* Free up compression resources. */ 3295 static void 3296 ppp_ccp_closed(struct ppp *ppp) 3297 { 3298 void *xstate, *rstate; 3299 struct compressor *xcomp, *rcomp; 3300 3301 ppp_lock(ppp); 3302 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP); 3303 ppp->xstate = 0; 3304 xcomp = ppp->xcomp; 3305 xstate = ppp->xc_state; 3306 ppp->xc_state = NULL; 3307 ppp->rstate = 0; 3308 rcomp = ppp->rcomp; 3309 rstate = ppp->rc_state; 3310 ppp->rc_state = NULL; 3311 ppp_unlock(ppp); 3312 3313 if (xstate) { 3314 xcomp->comp_free(xstate); 3315 module_put(xcomp->owner); 3316 } 3317 if (rstate) { 3318 rcomp->decomp_free(rstate); 3319 module_put(rcomp->owner); 3320 } 3321 } 3322 3323 /* List of compressors. */ 3324 static LIST_HEAD(compressor_list); 3325 static DEFINE_SPINLOCK(compressor_list_lock); 3326 3327 struct compressor_entry { 3328 struct list_head list; 3329 struct compressor *comp; 3330 }; 3331 3332 static struct compressor_entry * 3333 find_comp_entry(int proto) 3334 { 3335 struct compressor_entry *ce; 3336 3337 list_for_each_entry(ce, &compressor_list, list) { 3338 if (ce->comp->compress_proto == proto) 3339 return ce; 3340 } 3341 return NULL; 3342 } 3343 3344 /* Register a compressor */ 3345 int 3346 ppp_register_compressor(struct compressor *cp) 3347 { 3348 struct compressor_entry *ce; 3349 int ret; 3350 spin_lock(&compressor_list_lock); 3351 ret = -EEXIST; 3352 if (find_comp_entry(cp->compress_proto)) 3353 goto out; 3354 ret = -ENOMEM; 3355 ce = kmalloc_obj(struct compressor_entry, GFP_ATOMIC); 3356 if (!ce) 3357 goto out; 3358 ret = 0; 3359 ce->comp = cp; 3360 list_add(&ce->list, &compressor_list); 3361 out: 3362 spin_unlock(&compressor_list_lock); 3363 return ret; 3364 } 3365 3366 /* Unregister a compressor */ 3367 void 3368 ppp_unregister_compressor(struct compressor *cp) 3369 { 3370 struct compressor_entry *ce; 3371 3372 spin_lock(&compressor_list_lock); 3373 ce = find_comp_entry(cp->compress_proto); 3374 if (ce && ce->comp == cp) { 3375 list_del(&ce->list); 3376 kfree(ce); 3377 } 3378 spin_unlock(&compressor_list_lock); 3379 } 3380 3381 /* Find a compressor. */ 3382 static struct compressor * 3383 find_compressor(int type) 3384 { 3385 struct compressor_entry *ce; 3386 struct compressor *cp = NULL; 3387 3388 spin_lock(&compressor_list_lock); 3389 ce = find_comp_entry(type); 3390 if (ce) { 3391 cp = ce->comp; 3392 if (!try_module_get(cp->owner)) 3393 cp = NULL; 3394 } 3395 spin_unlock(&compressor_list_lock); 3396 return cp; 3397 } 3398 3399 /* 3400 * Miscelleneous stuff. 3401 */ 3402 3403 static void 3404 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st) 3405 { 3406 struct net_device *dev = netdev_from_priv(ppp); 3407 struct slcompress *vj = ppp->vj; 3408 int cpu; 3409 3410 memset(st, 0, sizeof(*st)); 3411 for_each_possible_cpu(cpu) { 3412 struct pcpu_sw_netstats *p = per_cpu_ptr(dev->tstats, cpu); 3413 u64 rx_packets, rx_bytes, tx_packets, tx_bytes; 3414 3415 rx_packets = u64_stats_read(&p->rx_packets); 3416 rx_bytes = u64_stats_read(&p->rx_bytes); 3417 tx_packets = u64_stats_read(&p->tx_packets); 3418 tx_bytes = u64_stats_read(&p->tx_bytes); 3419 3420 st->p.ppp_ipackets += rx_packets; 3421 st->p.ppp_ibytes += rx_bytes; 3422 st->p.ppp_opackets += tx_packets; 3423 st->p.ppp_obytes += tx_bytes; 3424 } 3425 st->p.ppp_ierrors = DEV_STATS_READ(dev, rx_errors); 3426 st->p.ppp_oerrors = DEV_STATS_READ(dev, tx_errors); 3427 if (!vj) 3428 return; 3429 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed; 3430 st->vj.vjs_compressed = vj->sls_o_compressed; 3431 st->vj.vjs_searches = vj->sls_o_searches; 3432 st->vj.vjs_misses = vj->sls_o_misses; 3433 st->vj.vjs_errorin = vj->sls_i_error; 3434 st->vj.vjs_tossed = vj->sls_i_tossed; 3435 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed; 3436 st->vj.vjs_compressedin = vj->sls_i_compressed; 3437 } 3438 3439 /* 3440 * Stuff for handling the lists of ppp units and channels 3441 * and for initialization. 3442 */ 3443 3444 /* 3445 * Create a new ppp interface unit. Fails if it can't allocate memory 3446 * or if there is already a unit with the requested number. 3447 * unit == -1 means allocate a new number. 3448 */ 3449 static int ppp_create_interface(struct net *net, struct file *file, int *unit) 3450 { 3451 struct ppp_config conf = { 3452 .file = file, 3453 .unit = *unit, 3454 .ifname_is_set = false, 3455 }; 3456 struct net_device *dev; 3457 struct ppp *ppp; 3458 int err; 3459 3460 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup); 3461 if (!dev) { 3462 err = -ENOMEM; 3463 goto err; 3464 } 3465 dev_net_set(dev, net); 3466 dev->rtnl_link_ops = &ppp_link_ops; 3467 3468 rtnl_lock(); 3469 3470 err = ppp_dev_configure(net, dev, &conf); 3471 if (err < 0) 3472 goto err_dev; 3473 ppp = netdev_priv(dev); 3474 *unit = ppp->file.index; 3475 3476 rtnl_unlock(); 3477 3478 return 0; 3479 3480 err_dev: 3481 rtnl_unlock(); 3482 free_netdev(dev); 3483 err: 3484 return err; 3485 } 3486 3487 /* 3488 * Initialize a ppp_file structure. 3489 */ 3490 static void 3491 init_ppp_file(struct ppp_file *pf, int kind) 3492 { 3493 pf->kind = kind; 3494 skb_queue_head_init(&pf->xq); 3495 skb_queue_head_init(&pf->rq); 3496 refcount_set(&pf->refcnt, 1); 3497 init_waitqueue_head(&pf->rwait); 3498 } 3499 3500 /* 3501 * Drop a reference to a ppp unit and free its memory if the refcount reaches 3502 * zero. 3503 */ 3504 static void ppp_release_interface(struct ppp *ppp) 3505 { 3506 struct net_device *dev = netdev_from_priv(ppp); 3507 3508 if (!refcount_dec_and_test(&ppp->file.refcnt)) 3509 return; 3510 3511 atomic_dec(&ppp_unit_count); 3512 3513 if (!ppp->file.dead || ppp->n_channels) { 3514 /* "can't happen" */ 3515 netdev_err(dev, "ppp: destroying ppp struct %p " 3516 "but dead=%d n_channels=%d !\n", 3517 ppp, ppp->file.dead, ppp->n_channels); 3518 return; 3519 } 3520 3521 ppp_ccp_closed(ppp); 3522 if (ppp->vj) { 3523 slhc_free(ppp->vj); 3524 ppp->vj = NULL; 3525 } 3526 skb_queue_purge(&ppp->file.xq); 3527 skb_queue_purge(&ppp->file.rq); 3528 #ifdef CONFIG_PPP_MULTILINK 3529 skb_queue_purge(&ppp->mrq); 3530 #endif /* CONFIG_PPP_MULTILINK */ 3531 #ifdef CONFIG_PPP_FILTER 3532 if (ppp->pass_filter) { 3533 bpf_prog_destroy(ppp->pass_filter); 3534 ppp->pass_filter = NULL; 3535 } 3536 3537 if (ppp->active_filter) { 3538 bpf_prog_destroy(ppp->active_filter); 3539 ppp->active_filter = NULL; 3540 } 3541 #endif /* CONFIG_PPP_FILTER */ 3542 3543 free_percpu(ppp->xmit_recursion); 3544 3545 free_netdev(dev); 3546 } 3547 3548 /* 3549 * Locate an existing ppp unit. 3550 * The caller should have locked the all_ppp_mutex. 3551 */ 3552 static struct ppp * 3553 ppp_find_unit(struct ppp_net *pn, int unit) 3554 { 3555 return unit_find(&pn->units_idr, unit); 3556 } 3557 3558 /* 3559 * Locate an existing ppp channel. 3560 * The caller should have locked the all_channels_lock. 3561 * First we look in the new_channels list, then in the 3562 * all_channels list. If found in the new_channels list, 3563 * we move it to the all_channels list. This is for speed 3564 * when we have a lot of channels in use. 3565 */ 3566 static struct channel * 3567 ppp_find_channel(struct ppp_net *pn, int unit) 3568 { 3569 struct channel *pch; 3570 3571 list_for_each_entry(pch, &pn->new_channels, list) { 3572 if (pch->file.index == unit) { 3573 list_move(&pch->list, &pn->all_channels); 3574 return pch; 3575 } 3576 } 3577 3578 list_for_each_entry(pch, &pn->all_channels, list) { 3579 if (pch->file.index == unit) 3580 return pch; 3581 } 3582 3583 return NULL; 3584 } 3585 3586 /* 3587 * Connect a PPP channel to a PPP interface unit. 3588 */ 3589 static int 3590 ppp_connect_channel(struct channel *pch, int unit) 3591 { 3592 struct net_device *dev; 3593 struct ppp *ppp; 3594 struct ppp_net *pn; 3595 int ret = -ENXIO; 3596 int hdrlen; 3597 3598 pn = ppp_pernet(pch->chan_net); 3599 3600 mutex_lock(&pn->all_ppp_mutex); 3601 ppp = ppp_find_unit(pn, unit); 3602 if (!ppp) 3603 goto out; 3604 dev = netdev_from_priv(ppp); 3605 spin_lock(&pch->upl); 3606 ret = -EINVAL; 3607 if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) || 3608 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) 3609 goto outl; 3610 3611 ppp_lock(ppp); 3612 spin_lock_bh(&pch->downl); 3613 if (!pch->chan) { 3614 /* Don't connect unregistered channels */ 3615 spin_unlock_bh(&pch->downl); 3616 ppp_unlock(ppp); 3617 ret = -ENOTCONN; 3618 goto outl; 3619 } 3620 if (pch->chan->direct_xmit) 3621 dev->priv_flags |= IFF_NO_QUEUE; 3622 else 3623 dev->priv_flags &= ~IFF_NO_QUEUE; 3624 spin_unlock_bh(&pch->downl); 3625 if (pch->file.hdrlen > ppp->file.hdrlen) 3626 ppp->file.hdrlen = pch->file.hdrlen; 3627 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */ 3628 if (hdrlen > dev->hard_header_len) 3629 dev->hard_header_len = hdrlen; 3630 list_add_tail_rcu(&pch->clist, &ppp->channels); 3631 ++ppp->n_channels; 3632 rcu_assign_pointer(pch->ppp, ppp); 3633 refcount_inc(&ppp->file.refcnt); 3634 ppp_unlock(ppp); 3635 ret = 0; 3636 3637 outl: 3638 spin_unlock(&pch->upl); 3639 out: 3640 mutex_unlock(&pn->all_ppp_mutex); 3641 return ret; 3642 } 3643 3644 /* 3645 * Disconnect a channel from its ppp unit. 3646 */ 3647 static int 3648 ppp_disconnect_channel(struct channel *pch) 3649 { 3650 struct ppp *ppp; 3651 int err = -EINVAL; 3652 3653 spin_lock(&pch->upl); 3654 ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl)); 3655 spin_unlock(&pch->upl); 3656 if (ppp) { 3657 /* remove it from the ppp unit's list */ 3658 ppp_lock(ppp); 3659 list_del_rcu(&pch->clist); 3660 if (--ppp->n_channels == 0) 3661 wake_up_interruptible(&ppp->file.rwait); 3662 ppp_unlock(ppp); 3663 synchronize_net(); 3664 ppp_release_interface(ppp); 3665 err = 0; 3666 } 3667 return err; 3668 } 3669 3670 /* Purge after the grace period: a late ppp_input() may still queue an 3671 * skb on pch->file.rq before the last RCU reader drains. 3672 */ 3673 static void ppp_release_channel_free(struct rcu_head *rcu) 3674 { 3675 struct channel *pch = container_of(rcu, struct channel, rcu); 3676 3677 skb_queue_purge(&pch->file.xq); 3678 skb_queue_purge(&pch->file.rq); 3679 kfree(pch); 3680 } 3681 3682 /* 3683 * Drop a reference to a ppp channel and free its memory if the refcount reaches 3684 * zero. 3685 */ 3686 static void ppp_release_channel(struct channel *pch) 3687 { 3688 if (!refcount_dec_and_test(&pch->file.refcnt)) 3689 return; 3690 3691 put_net_track(pch->chan_net, &pch->ns_tracker); 3692 pch->chan_net = NULL; 3693 3694 atomic_dec(&channel_count); 3695 3696 if (!pch->file.dead) { 3697 /* "can't happen" */ 3698 pr_err("ppp: destroying undead channel %p !\n", pch); 3699 return; 3700 } 3701 mutex_destroy(&pch->chan_sem); 3702 call_rcu(&pch->rcu, ppp_release_channel_free); 3703 } 3704 3705 static void __exit ppp_cleanup(void) 3706 { 3707 /* should never happen */ 3708 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count)) 3709 pr_err("PPP: removing module but units remain!\n"); 3710 rtnl_link_unregister(&ppp_link_ops); 3711 unregister_chrdev(PPP_MAJOR, "ppp"); 3712 device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0)); 3713 class_unregister(&ppp_class); 3714 unregister_pernet_device(&ppp_net_ops); 3715 rcu_barrier(); /* wait for RCU callbacks before module unload */ 3716 } 3717 3718 /* 3719 * Units handling. Caller must protect concurrent access 3720 * by holding all_ppp_mutex 3721 */ 3722 3723 /* associate pointer with specified number */ 3724 static int unit_set(struct idr *p, void *ptr, int n) 3725 { 3726 int unit; 3727 3728 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL); 3729 if (unit == -ENOSPC) 3730 unit = -EINVAL; 3731 return unit; 3732 } 3733 3734 /* get new free unit number and associate pointer with it */ 3735 static int unit_get(struct idr *p, void *ptr, int min) 3736 { 3737 return idr_alloc(p, ptr, min, 0, GFP_KERNEL); 3738 } 3739 3740 /* put unit number back to a pool */ 3741 static void unit_put(struct idr *p, int n) 3742 { 3743 idr_remove(p, n); 3744 } 3745 3746 /* get pointer associated with the number */ 3747 static void *unit_find(struct idr *p, int n) 3748 { 3749 return idr_find(p, n); 3750 } 3751 3752 /* Module/initialization stuff */ 3753 3754 module_init(ppp_init); 3755 module_exit(ppp_cleanup); 3756 3757 EXPORT_SYMBOL(ppp_register_net_channel); 3758 EXPORT_SYMBOL(ppp_register_channel); 3759 EXPORT_SYMBOL(ppp_unregister_channel); 3760 EXPORT_SYMBOL(ppp_channel_index); 3761 EXPORT_SYMBOL(ppp_unit_number); 3762 EXPORT_SYMBOL(ppp_dev_name); 3763 EXPORT_SYMBOL(ppp_input); 3764 EXPORT_SYMBOL(ppp_input_error); 3765 EXPORT_SYMBOL(ppp_output_wakeup); 3766 EXPORT_SYMBOL(ppp_register_compressor); 3767 EXPORT_SYMBOL(ppp_unregister_compressor); 3768 MODULE_DESCRIPTION("Generic PPP layer driver"); 3769 MODULE_LICENSE("GPL"); 3770 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0); 3771 MODULE_ALIAS_RTNL_LINK("ppp"); 3772 MODULE_ALIAS("devname:ppp"); 3773