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/rtnetlink.h> 37 #include <linux/if_arp.h> 38 #include <linux/ip.h> 39 #include <linux/tcp.h> 40 #include <linux/spinlock.h> 41 #include <linux/rwsem.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/slhc_vj.h> 49 #include <linux/atomic.h> 50 #include <linux/refcount.h> 51 52 #include <linux/nsproxy.h> 53 #include <net/net_namespace.h> 54 #include <net/netns/generic.h> 55 56 #define PPP_VERSION "2.4.2" 57 58 /* 59 * Network protocols we support. 60 */ 61 #define NP_IP 0 /* Internet Protocol V4 */ 62 #define NP_IPV6 1 /* Internet Protocol V6 */ 63 #define NP_IPX 2 /* IPX protocol */ 64 #define NP_AT 3 /* Appletalk protocol */ 65 #define NP_MPLS_UC 4 /* MPLS unicast */ 66 #define NP_MPLS_MC 5 /* MPLS multicast */ 67 #define NUM_NP 6 /* Number of NPs. */ 68 69 #define MPHDRLEN 6 /* multilink protocol header length */ 70 #define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */ 71 72 #define PPP_PROTO_LEN 2 73 #define PPP_LCP_HDRLEN 4 74 75 /* 76 * An instance of /dev/ppp can be associated with either a ppp 77 * interface unit or a ppp channel. In both cases, file->private_data 78 * points to one of these. 79 */ 80 struct ppp_file { 81 enum { 82 INTERFACE=1, CHANNEL 83 } kind; 84 struct sk_buff_head xq; /* pppd transmit queue */ 85 struct sk_buff_head rq; /* receive queue for pppd */ 86 wait_queue_head_t rwait; /* for poll on reading /dev/ppp */ 87 refcount_t refcnt; /* # refs (incl /dev/ppp attached) */ 88 int hdrlen; /* space to leave for headers */ 89 int index; /* interface unit / channel number */ 90 int dead; /* unit/channel has been shut down */ 91 }; 92 93 #define PF_TO_X(pf, X) container_of(pf, X, file) 94 95 #define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp) 96 #define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel) 97 98 /* 99 * Data structure to hold primary network stats for which 100 * we want to use 64 bit storage. Other network stats 101 * are stored in dev->stats of the ppp strucute. 102 */ 103 struct ppp_link_stats { 104 u64 rx_packets; 105 u64 tx_packets; 106 u64 rx_bytes; 107 u64 tx_bytes; 108 }; 109 110 /* 111 * Data structure describing one ppp unit. 112 * A ppp unit corresponds to a ppp network interface device 113 * and represents a multilink bundle. 114 * It can have 0 or more ppp channels connected to it. 115 */ 116 struct ppp { 117 struct ppp_file file; /* stuff for read/write/poll 0 */ 118 struct file *owner; /* file that owns this unit 48 */ 119 struct list_head channels; /* list of attached channels 4c */ 120 int n_channels; /* how many channels are attached 54 */ 121 spinlock_t rlock; /* lock for receive side 58 */ 122 spinlock_t wlock; /* lock for transmit side 5c */ 123 int __percpu *xmit_recursion; /* xmit recursion detect */ 124 int mru; /* max receive unit 60 */ 125 unsigned int flags; /* control bits 64 */ 126 unsigned int xstate; /* transmit state bits 68 */ 127 unsigned int rstate; /* receive state bits 6c */ 128 int debug; /* debug flags 70 */ 129 struct slcompress *vj; /* state for VJ header compression */ 130 enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */ 131 struct sk_buff *xmit_pending; /* a packet ready to go out 88 */ 132 struct compressor *xcomp; /* transmit packet compressor 8c */ 133 void *xc_state; /* its internal state 90 */ 134 struct compressor *rcomp; /* receive decompressor 94 */ 135 void *rc_state; /* its internal state 98 */ 136 unsigned long last_xmit; /* jiffies when last pkt sent 9c */ 137 unsigned long last_recv; /* jiffies when last pkt rcvd a0 */ 138 struct net_device *dev; /* network interface device a4 */ 139 int closing; /* is device closing down? a8 */ 140 #ifdef CONFIG_PPP_MULTILINK 141 int nxchan; /* next channel to send something on */ 142 u32 nxseq; /* next sequence number to send */ 143 int mrru; /* MP: max reconst. receive unit */ 144 u32 nextseq; /* MP: seq no of next packet */ 145 u32 minseq; /* MP: min of most recent seqnos */ 146 struct sk_buff_head mrq; /* MP: receive reconstruction queue */ 147 #endif /* CONFIG_PPP_MULTILINK */ 148 #ifdef CONFIG_PPP_FILTER 149 struct bpf_prog *pass_filter; /* filter for packets to pass */ 150 struct bpf_prog *active_filter; /* filter for pkts to reset idle */ 151 #endif /* CONFIG_PPP_FILTER */ 152 struct net *ppp_net; /* the net we belong to */ 153 struct ppp_link_stats stats64; /* 64 bit network stats */ 154 }; 155 156 /* 157 * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC, 158 * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP, 159 * SC_MUST_COMP 160 * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR. 161 * Bits in xstate: SC_COMP_RUN 162 */ 163 #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \ 164 |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \ 165 |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP) 166 167 /* 168 * Private data structure for each channel. 169 * This includes the data structure used for multilink. 170 */ 171 struct channel { 172 struct ppp_file file; /* stuff for read/write/poll */ 173 struct list_head list; /* link in all/new_channels list */ 174 struct ppp_channel *chan; /* public channel data structure */ 175 struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */ 176 spinlock_t downl; /* protects `chan', file.xq dequeue */ 177 struct ppp *ppp; /* ppp unit we're connected to */ 178 struct net *chan_net; /* the net channel belongs to */ 179 netns_tracker ns_tracker; 180 struct list_head clist; /* link in list of channels per unit */ 181 rwlock_t upl; /* protects `ppp' and 'bridge' */ 182 struct channel __rcu *bridge; /* "bridged" ppp channel */ 183 #ifdef CONFIG_PPP_MULTILINK 184 u8 avail; /* flag used in multilink stuff */ 185 u8 had_frag; /* >= 1 fragments have been sent */ 186 u32 lastseq; /* MP: last sequence # received */ 187 int speed; /* speed of the corresponding ppp channel*/ 188 #endif /* CONFIG_PPP_MULTILINK */ 189 }; 190 191 struct ppp_config { 192 struct file *file; 193 s32 unit; 194 bool ifname_is_set; 195 }; 196 197 /* 198 * SMP locking issues: 199 * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels 200 * list and the ppp.n_channels field, you need to take both locks 201 * before you modify them. 202 * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock -> 203 * channel.downl. 204 */ 205 206 static DEFINE_MUTEX(ppp_mutex); 207 static atomic_t ppp_unit_count = ATOMIC_INIT(0); 208 static atomic_t channel_count = ATOMIC_INIT(0); 209 210 /* per-net private data for this module */ 211 static unsigned int ppp_net_id __read_mostly; 212 struct ppp_net { 213 /* units to ppp mapping */ 214 struct idr units_idr; 215 216 /* 217 * all_ppp_mutex protects the units_idr mapping. 218 * It also ensures that finding a ppp unit in the units_idr 219 * map and updating its file.refcnt field is atomic. 220 */ 221 struct mutex all_ppp_mutex; 222 223 /* channels */ 224 struct list_head all_channels; 225 struct list_head new_channels; 226 int last_channel_index; 227 228 /* 229 * all_channels_lock protects all_channels and 230 * last_channel_index, and the atomicity of find 231 * a channel and updating its file.refcnt field. 232 */ 233 spinlock_t all_channels_lock; 234 }; 235 236 /* Get the PPP protocol number from a skb */ 237 #define PPP_PROTO(skb) get_unaligned_be16((skb)->data) 238 239 /* We limit the length of ppp->file.rq to this (arbitrary) value */ 240 #define PPP_MAX_RQLEN 32 241 242 /* 243 * Maximum number of multilink fragments queued up. 244 * This has to be large enough to cope with the maximum latency of 245 * the slowest channel relative to the others. Strictly it should 246 * depend on the number of channels and their characteristics. 247 */ 248 #define PPP_MP_MAX_QLEN 128 249 250 /* Multilink header bits. */ 251 #define B 0x80 /* this fragment begins a packet */ 252 #define E 0x40 /* this fragment ends a packet */ 253 254 /* Compare multilink sequence numbers (assumed to be 32 bits wide) */ 255 #define seq_before(a, b) ((s32)((a) - (b)) < 0) 256 #define seq_after(a, b) ((s32)((a) - (b)) > 0) 257 258 /* Prototypes. */ 259 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, 260 struct file *file, unsigned int cmd, unsigned long arg); 261 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb); 262 static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb); 263 static void ppp_push(struct ppp *ppp); 264 static void ppp_channel_push(struct channel *pch); 265 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, 266 struct channel *pch); 267 static void ppp_receive_error(struct ppp *ppp); 268 static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb); 269 static struct sk_buff *ppp_decompress_frame(struct ppp *ppp, 270 struct sk_buff *skb); 271 #ifdef CONFIG_PPP_MULTILINK 272 static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, 273 struct channel *pch); 274 static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb); 275 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp); 276 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb); 277 #endif /* CONFIG_PPP_MULTILINK */ 278 static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data); 279 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound); 280 static void ppp_ccp_closed(struct ppp *ppp); 281 static struct compressor *find_compressor(int type); 282 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st); 283 static int ppp_create_interface(struct net *net, struct file *file, int *unit); 284 static void init_ppp_file(struct ppp_file *pf, int kind); 285 static void ppp_destroy_interface(struct ppp *ppp); 286 static struct ppp *ppp_find_unit(struct ppp_net *pn, int unit); 287 static struct channel *ppp_find_channel(struct ppp_net *pn, int unit); 288 static int ppp_connect_channel(struct channel *pch, int unit); 289 static int ppp_disconnect_channel(struct channel *pch); 290 static void ppp_destroy_channel(struct channel *pch); 291 static int unit_get(struct idr *p, void *ptr, int min); 292 static int unit_set(struct idr *p, void *ptr, int n); 293 static void unit_put(struct idr *p, int n); 294 static void *unit_find(struct idr *p, int n); 295 static void ppp_setup(struct net_device *dev); 296 297 static const struct net_device_ops ppp_netdev_ops; 298 299 static const struct class ppp_class = { 300 .name = "ppp", 301 }; 302 303 /* per net-namespace data */ 304 static inline struct ppp_net *ppp_pernet(struct net *net) 305 { 306 return net_generic(net, ppp_net_id); 307 } 308 309 /* Translates a PPP protocol number to a NP index (NP == network protocol) */ 310 static inline int proto_to_npindex(int proto) 311 { 312 switch (proto) { 313 case PPP_IP: 314 return NP_IP; 315 case PPP_IPV6: 316 return NP_IPV6; 317 case PPP_IPX: 318 return NP_IPX; 319 case PPP_AT: 320 return NP_AT; 321 case PPP_MPLS_UC: 322 return NP_MPLS_UC; 323 case PPP_MPLS_MC: 324 return NP_MPLS_MC; 325 } 326 return -EINVAL; 327 } 328 329 /* Translates an NP index into a PPP protocol number */ 330 static const int npindex_to_proto[NUM_NP] = { 331 PPP_IP, 332 PPP_IPV6, 333 PPP_IPX, 334 PPP_AT, 335 PPP_MPLS_UC, 336 PPP_MPLS_MC, 337 }; 338 339 /* Translates an ethertype into an NP index */ 340 static inline int ethertype_to_npindex(int ethertype) 341 { 342 switch (ethertype) { 343 case ETH_P_IP: 344 return NP_IP; 345 case ETH_P_IPV6: 346 return NP_IPV6; 347 case ETH_P_IPX: 348 return NP_IPX; 349 case ETH_P_PPPTALK: 350 case ETH_P_ATALK: 351 return NP_AT; 352 case ETH_P_MPLS_UC: 353 return NP_MPLS_UC; 354 case ETH_P_MPLS_MC: 355 return NP_MPLS_MC; 356 } 357 return -1; 358 } 359 360 /* Translates an NP index into an ethertype */ 361 static const int npindex_to_ethertype[NUM_NP] = { 362 ETH_P_IP, 363 ETH_P_IPV6, 364 ETH_P_IPX, 365 ETH_P_PPPTALK, 366 ETH_P_MPLS_UC, 367 ETH_P_MPLS_MC, 368 }; 369 370 /* 371 * Locking shorthand. 372 */ 373 #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock) 374 #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock) 375 #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock) 376 #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock) 377 #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \ 378 ppp_recv_lock(ppp); } while (0) 379 #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \ 380 ppp_xmit_unlock(ppp); } while (0) 381 382 /* 383 * /dev/ppp device routines. 384 * The /dev/ppp device is used by pppd to control the ppp unit. 385 * It supports the read, write, ioctl and poll functions. 386 * Open instances of /dev/ppp can be in one of three states: 387 * unattached, attached to a ppp unit, or attached to a ppp channel. 388 */ 389 static int ppp_open(struct inode *inode, struct file *file) 390 { 391 /* 392 * This could (should?) be enforced by the permissions on /dev/ppp. 393 */ 394 if (!ns_capable(file->f_cred->user_ns, CAP_NET_ADMIN)) 395 return -EPERM; 396 return 0; 397 } 398 399 static int ppp_release(struct inode *unused, struct file *file) 400 { 401 struct ppp_file *pf = file->private_data; 402 struct ppp *ppp; 403 404 if (pf) { 405 file->private_data = NULL; 406 if (pf->kind == INTERFACE) { 407 ppp = PF_TO_PPP(pf); 408 rtnl_lock(); 409 if (file == ppp->owner) 410 unregister_netdevice(ppp->dev); 411 rtnl_unlock(); 412 } 413 if (refcount_dec_and_test(&pf->refcnt)) { 414 switch (pf->kind) { 415 case INTERFACE: 416 ppp_destroy_interface(PF_TO_PPP(pf)); 417 break; 418 case CHANNEL: 419 ppp_destroy_channel(PF_TO_CHANNEL(pf)); 420 break; 421 } 422 } 423 } 424 return 0; 425 } 426 427 static ssize_t ppp_read(struct file *file, char __user *buf, 428 size_t count, loff_t *ppos) 429 { 430 struct ppp_file *pf = file->private_data; 431 DECLARE_WAITQUEUE(wait, current); 432 ssize_t ret; 433 struct sk_buff *skb = NULL; 434 struct iovec iov; 435 struct iov_iter to; 436 437 ret = count; 438 439 if (!pf) 440 return -ENXIO; 441 add_wait_queue(&pf->rwait, &wait); 442 for (;;) { 443 set_current_state(TASK_INTERRUPTIBLE); 444 skb = skb_dequeue(&pf->rq); 445 if (skb) 446 break; 447 ret = 0; 448 if (pf->dead) 449 break; 450 if (pf->kind == INTERFACE) { 451 /* 452 * Return 0 (EOF) on an interface that has no 453 * channels connected, unless it is looping 454 * network traffic (demand mode). 455 */ 456 struct ppp *ppp = PF_TO_PPP(pf); 457 458 ppp_recv_lock(ppp); 459 if (ppp->n_channels == 0 && 460 (ppp->flags & SC_LOOP_TRAFFIC) == 0) { 461 ppp_recv_unlock(ppp); 462 break; 463 } 464 ppp_recv_unlock(ppp); 465 } 466 ret = -EAGAIN; 467 if (file->f_flags & O_NONBLOCK) 468 break; 469 ret = -ERESTARTSYS; 470 if (signal_pending(current)) 471 break; 472 schedule(); 473 } 474 set_current_state(TASK_RUNNING); 475 remove_wait_queue(&pf->rwait, &wait); 476 477 if (!skb) 478 goto out; 479 480 ret = -EOVERFLOW; 481 if (skb->len > count) 482 goto outf; 483 ret = -EFAULT; 484 iov.iov_base = buf; 485 iov.iov_len = count; 486 iov_iter_init(&to, ITER_DEST, &iov, 1, count); 487 if (skb_copy_datagram_iter(skb, 0, &to, skb->len)) 488 goto outf; 489 ret = skb->len; 490 491 outf: 492 kfree_skb(skb); 493 out: 494 return ret; 495 } 496 497 static bool ppp_check_packet(struct sk_buff *skb, size_t count) 498 { 499 /* LCP packets must include LCP header which 4 bytes long: 500 * 1-byte code, 1-byte identifier, and 2-byte length. 501 */ 502 return get_unaligned_be16(skb->data) != PPP_LCP || 503 count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN; 504 } 505 506 static ssize_t ppp_write(struct file *file, const char __user *buf, 507 size_t count, loff_t *ppos) 508 { 509 struct ppp_file *pf = file->private_data; 510 struct sk_buff *skb; 511 ssize_t ret; 512 513 if (!pf) 514 return -ENXIO; 515 /* All PPP packets should start with the 2-byte protocol */ 516 if (count < PPP_PROTO_LEN) 517 return -EINVAL; 518 ret = -ENOMEM; 519 skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL); 520 if (!skb) 521 goto out; 522 skb_reserve(skb, pf->hdrlen); 523 ret = -EFAULT; 524 if (copy_from_user(skb_put(skb, count), buf, count)) { 525 kfree_skb(skb); 526 goto out; 527 } 528 ret = -EINVAL; 529 if (unlikely(!ppp_check_packet(skb, count))) { 530 kfree_skb(skb); 531 goto out; 532 } 533 534 switch (pf->kind) { 535 case INTERFACE: 536 ppp_xmit_process(PF_TO_PPP(pf), skb); 537 break; 538 case CHANNEL: 539 skb_queue_tail(&pf->xq, skb); 540 ppp_channel_push(PF_TO_CHANNEL(pf)); 541 break; 542 } 543 544 ret = count; 545 546 out: 547 return ret; 548 } 549 550 /* No kernel lock - fine */ 551 static __poll_t ppp_poll(struct file *file, poll_table *wait) 552 { 553 struct ppp_file *pf = file->private_data; 554 __poll_t mask; 555 556 if (!pf) 557 return 0; 558 poll_wait(file, &pf->rwait, wait); 559 mask = EPOLLOUT | EPOLLWRNORM; 560 if (skb_peek(&pf->rq)) 561 mask |= EPOLLIN | EPOLLRDNORM; 562 if (pf->dead) 563 mask |= EPOLLHUP; 564 else if (pf->kind == INTERFACE) { 565 /* see comment in ppp_read */ 566 struct ppp *ppp = PF_TO_PPP(pf); 567 568 ppp_recv_lock(ppp); 569 if (ppp->n_channels == 0 && 570 (ppp->flags & SC_LOOP_TRAFFIC) == 0) 571 mask |= EPOLLIN | EPOLLRDNORM; 572 ppp_recv_unlock(ppp); 573 } 574 575 return mask; 576 } 577 578 #ifdef CONFIG_PPP_FILTER 579 static struct bpf_prog *get_filter(struct sock_fprog *uprog) 580 { 581 struct sock_fprog_kern fprog; 582 struct bpf_prog *res = NULL; 583 int err; 584 585 if (!uprog->len) 586 return NULL; 587 588 /* uprog->len is unsigned short, so no overflow here */ 589 fprog.len = uprog->len; 590 fprog.filter = memdup_array_user(uprog->filter, 591 uprog->len, sizeof(struct sock_filter)); 592 if (IS_ERR(fprog.filter)) 593 return ERR_CAST(fprog.filter); 594 595 err = bpf_prog_create(&res, &fprog); 596 kfree(fprog.filter); 597 598 return err ? ERR_PTR(err) : res; 599 } 600 601 static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p) 602 { 603 struct sock_fprog uprog; 604 605 if (copy_from_user(&uprog, p, sizeof(struct sock_fprog))) 606 return ERR_PTR(-EFAULT); 607 return get_filter(&uprog); 608 } 609 610 #ifdef CONFIG_COMPAT 611 struct sock_fprog32 { 612 unsigned short len; 613 compat_caddr_t filter; 614 }; 615 616 #define PPPIOCSPASS32 _IOW('t', 71, struct sock_fprog32) 617 #define PPPIOCSACTIVE32 _IOW('t', 70, struct sock_fprog32) 618 619 static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p) 620 { 621 struct sock_fprog32 uprog32; 622 struct sock_fprog uprog; 623 624 if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32))) 625 return ERR_PTR(-EFAULT); 626 uprog.len = uprog32.len; 627 uprog.filter = compat_ptr(uprog32.filter); 628 return get_filter(&uprog); 629 } 630 #endif 631 #endif 632 633 /* Bridge one PPP channel to another. 634 * When two channels are bridged, ppp_input on one channel is redirected to 635 * the other's ops->start_xmit handler. 636 * In order to safely bridge channels we must reject channels which are already 637 * part of a bridge instance, or which form part of an existing unit. 638 * Once successfully bridged, each channel holds a reference on the other 639 * to prevent it being freed while the bridge is extant. 640 */ 641 static int ppp_bridge_channels(struct channel *pch, struct channel *pchb) 642 { 643 write_lock_bh(&pch->upl); 644 if (pch->ppp || 645 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) { 646 write_unlock_bh(&pch->upl); 647 return -EALREADY; 648 } 649 refcount_inc(&pchb->file.refcnt); 650 rcu_assign_pointer(pch->bridge, pchb); 651 write_unlock_bh(&pch->upl); 652 653 write_lock_bh(&pchb->upl); 654 if (pchb->ppp || 655 rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) { 656 write_unlock_bh(&pchb->upl); 657 goto err_unset; 658 } 659 refcount_inc(&pch->file.refcnt); 660 rcu_assign_pointer(pchb->bridge, pch); 661 write_unlock_bh(&pchb->upl); 662 663 return 0; 664 665 err_unset: 666 write_lock_bh(&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 write_unlock_bh(&pch->upl); 671 synchronize_rcu(); 672 673 if (pchb) 674 if (refcount_dec_and_test(&pchb->file.refcnt)) 675 ppp_destroy_channel(pchb); 676 677 return -EALREADY; 678 } 679 680 static int ppp_unbridge_channels(struct channel *pch) 681 { 682 struct channel *pchb, *pchbb; 683 684 write_lock_bh(&pch->upl); 685 pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)); 686 if (!pchb) { 687 write_unlock_bh(&pch->upl); 688 return -EINVAL; 689 } 690 RCU_INIT_POINTER(pch->bridge, NULL); 691 write_unlock_bh(&pch->upl); 692 693 /* Only modify pchb if phcb->bridge points back to pch. 694 * If not, it implies that there has been a race unbridging (and possibly 695 * even rebridging) pchb. We should leave pchb alone to avoid either a 696 * refcount underflow, or breaking another established bridge instance. 697 */ 698 write_lock_bh(&pchb->upl); 699 pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl)); 700 if (pchbb == pch) 701 RCU_INIT_POINTER(pchb->bridge, NULL); 702 write_unlock_bh(&pchb->upl); 703 704 synchronize_rcu(); 705 706 if (pchbb == pch) 707 if (refcount_dec_and_test(&pch->file.refcnt)) 708 ppp_destroy_channel(pch); 709 710 if (refcount_dec_and_test(&pchb->file.refcnt)) 711 ppp_destroy_channel(pchb); 712 713 return 0; 714 } 715 716 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 717 { 718 struct ppp_file *pf; 719 struct ppp *ppp; 720 int err = -EFAULT, val, val2, i; 721 struct ppp_idle32 idle32; 722 struct ppp_idle64 idle64; 723 struct npioctl npi; 724 int unit, cflags; 725 struct slcompress *vj; 726 void __user *argp = (void __user *)arg; 727 int __user *p = argp; 728 729 mutex_lock(&ppp_mutex); 730 731 pf = file->private_data; 732 if (!pf) { 733 err = ppp_unattached_ioctl(current->nsproxy->net_ns, 734 pf, file, cmd, arg); 735 goto out; 736 } 737 738 if (cmd == PPPIOCDETACH) { 739 /* 740 * PPPIOCDETACH is no longer supported as it was heavily broken, 741 * and is only known to have been used by pppd older than 742 * ppp-2.4.2 (released November 2003). 743 */ 744 pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n", 745 current->comm, current->pid); 746 err = -EINVAL; 747 goto out; 748 } 749 750 if (pf->kind == CHANNEL) { 751 struct channel *pch, *pchb; 752 struct ppp_channel *chan; 753 struct ppp_net *pn; 754 755 pch = PF_TO_CHANNEL(pf); 756 757 switch (cmd) { 758 case PPPIOCCONNECT: 759 if (get_user(unit, p)) 760 break; 761 err = ppp_connect_channel(pch, unit); 762 break; 763 764 case PPPIOCDISCONN: 765 err = ppp_disconnect_channel(pch); 766 break; 767 768 case PPPIOCBRIDGECHAN: 769 if (get_user(unit, p)) 770 break; 771 err = -ENXIO; 772 pn = ppp_pernet(current->nsproxy->net_ns); 773 spin_lock_bh(&pn->all_channels_lock); 774 pchb = ppp_find_channel(pn, unit); 775 /* Hold a reference to prevent pchb being freed while 776 * we establish the bridge. 777 */ 778 if (pchb) 779 refcount_inc(&pchb->file.refcnt); 780 spin_unlock_bh(&pn->all_channels_lock); 781 if (!pchb) 782 break; 783 err = ppp_bridge_channels(pch, pchb); 784 /* Drop earlier refcount now bridge establishment is complete */ 785 if (refcount_dec_and_test(&pchb->file.refcnt)) 786 ppp_destroy_channel(pchb); 787 break; 788 789 case PPPIOCUNBRIDGECHAN: 790 err = ppp_unbridge_channels(pch); 791 break; 792 793 default: 794 down_read(&pch->chan_sem); 795 chan = pch->chan; 796 err = -ENOTTY; 797 if (chan && chan->ops->ioctl) 798 err = chan->ops->ioctl(chan, cmd, arg); 799 up_read(&pch->chan_sem); 800 } 801 goto out; 802 } 803 804 if (pf->kind != INTERFACE) { 805 /* can't happen */ 806 pr_err("PPP: not interface or channel??\n"); 807 err = -EINVAL; 808 goto out; 809 } 810 811 ppp = PF_TO_PPP(pf); 812 switch (cmd) { 813 case PPPIOCSMRU: 814 if (get_user(val, p)) 815 break; 816 ppp->mru = val; 817 err = 0; 818 break; 819 820 case PPPIOCSFLAGS: 821 if (get_user(val, p)) 822 break; 823 ppp_lock(ppp); 824 cflags = ppp->flags & ~val; 825 #ifdef CONFIG_PPP_MULTILINK 826 if (!(ppp->flags & SC_MULTILINK) && (val & SC_MULTILINK)) 827 ppp->nextseq = 0; 828 #endif 829 ppp->flags = val & SC_FLAG_BITS; 830 ppp_unlock(ppp); 831 if (cflags & SC_CCP_OPEN) 832 ppp_ccp_closed(ppp); 833 err = 0; 834 break; 835 836 case PPPIOCGFLAGS: 837 val = ppp->flags | ppp->xstate | ppp->rstate; 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 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 = (jiffies - ppp->last_xmit) / HZ; 873 idle32.recv_idle = (jiffies - 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 = (jiffies - ppp->last_xmit) / HZ; 881 idle64.recv_idle = (jiffies - 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 ppp->npmode[i] = npi.mode; 923 /* we may be able to transmit more packets now (??) */ 924 netif_wake_queue(ppp->dev); 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 switch (cmd) { 1056 case PPPIOCNEWUNIT: 1057 /* Create a new ppp unit */ 1058 if (get_user(unit, p)) 1059 break; 1060 err = ppp_create_interface(net, file, &unit); 1061 if (err < 0) 1062 break; 1063 1064 err = -EFAULT; 1065 if (put_user(unit, p)) 1066 break; 1067 err = 0; 1068 break; 1069 1070 case PPPIOCATTACH: 1071 /* Attach to an existing ppp unit */ 1072 if (get_user(unit, p)) 1073 break; 1074 err = -ENXIO; 1075 pn = ppp_pernet(net); 1076 mutex_lock(&pn->all_ppp_mutex); 1077 ppp = ppp_find_unit(pn, unit); 1078 if (ppp) { 1079 refcount_inc(&ppp->file.refcnt); 1080 file->private_data = &ppp->file; 1081 err = 0; 1082 } 1083 mutex_unlock(&pn->all_ppp_mutex); 1084 break; 1085 1086 case PPPIOCATTCHAN: 1087 if (get_user(unit, p)) 1088 break; 1089 err = -ENXIO; 1090 pn = ppp_pernet(net); 1091 spin_lock_bh(&pn->all_channels_lock); 1092 chan = ppp_find_channel(pn, unit); 1093 if (chan) { 1094 refcount_inc(&chan->file.refcnt); 1095 file->private_data = &chan->file; 1096 err = 0; 1097 } 1098 spin_unlock_bh(&pn->all_channels_lock); 1099 break; 1100 1101 default: 1102 err = -ENOTTY; 1103 } 1104 1105 return err; 1106 } 1107 1108 static const struct file_operations ppp_device_fops = { 1109 .owner = THIS_MODULE, 1110 .read = ppp_read, 1111 .write = ppp_write, 1112 .poll = ppp_poll, 1113 .unlocked_ioctl = ppp_ioctl, 1114 #ifdef CONFIG_COMPAT 1115 .compat_ioctl = ppp_compat_ioctl, 1116 #endif 1117 .open = ppp_open, 1118 .release = ppp_release, 1119 .llseek = noop_llseek, 1120 }; 1121 1122 static __net_init int ppp_init_net(struct net *net) 1123 { 1124 struct ppp_net *pn = net_generic(net, ppp_net_id); 1125 1126 idr_init(&pn->units_idr); 1127 mutex_init(&pn->all_ppp_mutex); 1128 1129 INIT_LIST_HEAD(&pn->all_channels); 1130 INIT_LIST_HEAD(&pn->new_channels); 1131 1132 spin_lock_init(&pn->all_channels_lock); 1133 1134 return 0; 1135 } 1136 1137 static __net_exit void ppp_exit_net(struct net *net) 1138 { 1139 struct ppp_net *pn = net_generic(net, ppp_net_id); 1140 struct net_device *dev; 1141 struct net_device *aux; 1142 struct ppp *ppp; 1143 LIST_HEAD(list); 1144 int id; 1145 1146 rtnl_lock(); 1147 for_each_netdev_safe(net, dev, aux) { 1148 if (dev->netdev_ops == &ppp_netdev_ops) 1149 unregister_netdevice_queue(dev, &list); 1150 } 1151 1152 idr_for_each_entry(&pn->units_idr, ppp, id) 1153 /* Skip devices already unregistered by previous loop */ 1154 if (!net_eq(dev_net(ppp->dev), net)) 1155 unregister_netdevice_queue(ppp->dev, &list); 1156 1157 unregister_netdevice_many(&list); 1158 rtnl_unlock(); 1159 1160 mutex_destroy(&pn->all_ppp_mutex); 1161 idr_destroy(&pn->units_idr); 1162 WARN_ON_ONCE(!list_empty(&pn->all_channels)); 1163 WARN_ON_ONCE(!list_empty(&pn->new_channels)); 1164 } 1165 1166 static struct pernet_operations ppp_net_ops = { 1167 .init = ppp_init_net, 1168 .exit = ppp_exit_net, 1169 .id = &ppp_net_id, 1170 .size = sizeof(struct ppp_net), 1171 }; 1172 1173 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set) 1174 { 1175 struct ppp_net *pn = ppp_pernet(ppp->ppp_net); 1176 int ret; 1177 1178 mutex_lock(&pn->all_ppp_mutex); 1179 1180 if (unit < 0) { 1181 ret = unit_get(&pn->units_idr, ppp, 0); 1182 if (ret < 0) 1183 goto err; 1184 if (!ifname_is_set) { 1185 while (1) { 1186 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret); 1187 if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name)) 1188 break; 1189 unit_put(&pn->units_idr, ret); 1190 ret = unit_get(&pn->units_idr, ppp, ret + 1); 1191 if (ret < 0) 1192 goto err; 1193 } 1194 } 1195 } else { 1196 /* Caller asked for a specific unit number. Fail with -EEXIST 1197 * if unavailable. For backward compatibility, return -EEXIST 1198 * too if idr allocation fails; this makes pppd retry without 1199 * requesting a specific unit number. 1200 */ 1201 if (unit_find(&pn->units_idr, unit)) { 1202 ret = -EEXIST; 1203 goto err; 1204 } 1205 ret = unit_set(&pn->units_idr, ppp, unit); 1206 if (ret < 0) { 1207 /* Rewrite error for backward compatibility */ 1208 ret = -EEXIST; 1209 goto err; 1210 } 1211 } 1212 ppp->file.index = ret; 1213 1214 if (!ifname_is_set) 1215 snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index); 1216 1217 mutex_unlock(&pn->all_ppp_mutex); 1218 1219 ret = register_netdevice(ppp->dev); 1220 if (ret < 0) 1221 goto err_unit; 1222 1223 atomic_inc(&ppp_unit_count); 1224 1225 return 0; 1226 1227 err_unit: 1228 mutex_lock(&pn->all_ppp_mutex); 1229 unit_put(&pn->units_idr, ppp->file.index); 1230 err: 1231 mutex_unlock(&pn->all_ppp_mutex); 1232 1233 return ret; 1234 } 1235 1236 static int ppp_dev_configure(struct net *src_net, struct net_device *dev, 1237 const struct ppp_config *conf) 1238 { 1239 struct ppp *ppp = netdev_priv(dev); 1240 int indx; 1241 int err; 1242 int cpu; 1243 1244 ppp->dev = dev; 1245 ppp->ppp_net = src_net; 1246 ppp->mru = PPP_MRU; 1247 ppp->owner = conf->file; 1248 1249 init_ppp_file(&ppp->file, INTERFACE); 1250 ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */ 1251 1252 for (indx = 0; indx < NUM_NP; ++indx) 1253 ppp->npmode[indx] = NPMODE_PASS; 1254 INIT_LIST_HEAD(&ppp->channels); 1255 spin_lock_init(&ppp->rlock); 1256 spin_lock_init(&ppp->wlock); 1257 1258 ppp->xmit_recursion = alloc_percpu(int); 1259 if (!ppp->xmit_recursion) { 1260 err = -ENOMEM; 1261 goto err1; 1262 } 1263 for_each_possible_cpu(cpu) 1264 (*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0; 1265 1266 #ifdef CONFIG_PPP_MULTILINK 1267 ppp->minseq = -1; 1268 skb_queue_head_init(&ppp->mrq); 1269 #endif /* CONFIG_PPP_MULTILINK */ 1270 #ifdef CONFIG_PPP_FILTER 1271 ppp->pass_filter = NULL; 1272 ppp->active_filter = NULL; 1273 #endif /* CONFIG_PPP_FILTER */ 1274 1275 err = ppp_unit_register(ppp, conf->unit, conf->ifname_is_set); 1276 if (err < 0) 1277 goto err2; 1278 1279 conf->file->private_data = &ppp->file; 1280 1281 return 0; 1282 err2: 1283 free_percpu(ppp->xmit_recursion); 1284 err1: 1285 return err; 1286 } 1287 1288 static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = { 1289 [IFLA_PPP_DEV_FD] = { .type = NLA_S32 }, 1290 }; 1291 1292 static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[], 1293 struct netlink_ext_ack *extack) 1294 { 1295 if (!data) 1296 return -EINVAL; 1297 1298 if (!data[IFLA_PPP_DEV_FD]) 1299 return -EINVAL; 1300 if (nla_get_s32(data[IFLA_PPP_DEV_FD]) < 0) 1301 return -EBADF; 1302 1303 return 0; 1304 } 1305 1306 static int ppp_nl_newlink(struct net_device *dev, 1307 struct rtnl_newlink_params *params, 1308 struct netlink_ext_ack *extack) 1309 { 1310 struct net *link_net = rtnl_newlink_link_net(params); 1311 struct nlattr **data = params->data; 1312 struct nlattr **tb = params->tb; 1313 struct ppp_config conf = { 1314 .unit = -1, 1315 .ifname_is_set = true, 1316 }; 1317 struct file *file; 1318 int err; 1319 1320 file = fget(nla_get_s32(data[IFLA_PPP_DEV_FD])); 1321 if (!file) 1322 return -EBADF; 1323 1324 /* rtnl_lock is already held here, but ppp_create_interface() locks 1325 * ppp_mutex before holding rtnl_lock. Using mutex_trylock() avoids 1326 * possible deadlock due to lock order inversion, at the cost of 1327 * pushing the problem back to userspace. 1328 */ 1329 if (!mutex_trylock(&ppp_mutex)) { 1330 err = -EBUSY; 1331 goto out; 1332 } 1333 1334 if (file->f_op != &ppp_device_fops || file->private_data) { 1335 err = -EBADF; 1336 goto out_unlock; 1337 } 1338 1339 conf.file = file; 1340 1341 /* Don't use device name generated by the rtnetlink layer when ifname 1342 * isn't specified. Let ppp_dev_configure() set the device name using 1343 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows 1344 * userspace to infer the device name using to the PPPIOCGUNIT ioctl. 1345 */ 1346 if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME])) 1347 conf.ifname_is_set = false; 1348 1349 err = ppp_dev_configure(link_net, dev, &conf); 1350 1351 out_unlock: 1352 mutex_unlock(&ppp_mutex); 1353 out: 1354 fput(file); 1355 1356 return err; 1357 } 1358 1359 static void ppp_nl_dellink(struct net_device *dev, struct list_head *head) 1360 { 1361 unregister_netdevice_queue(dev, head); 1362 } 1363 1364 static size_t ppp_nl_get_size(const struct net_device *dev) 1365 { 1366 return 0; 1367 } 1368 1369 static int ppp_nl_fill_info(struct sk_buff *skb, const struct net_device *dev) 1370 { 1371 return 0; 1372 } 1373 1374 static struct net *ppp_nl_get_link_net(const struct net_device *dev) 1375 { 1376 struct ppp *ppp = netdev_priv(dev); 1377 1378 return READ_ONCE(ppp->ppp_net); 1379 } 1380 1381 static struct rtnl_link_ops ppp_link_ops __read_mostly = { 1382 .kind = "ppp", 1383 .maxtype = IFLA_PPP_MAX, 1384 .policy = ppp_nl_policy, 1385 .priv_size = sizeof(struct ppp), 1386 .setup = ppp_setup, 1387 .validate = ppp_nl_validate, 1388 .newlink = ppp_nl_newlink, 1389 .dellink = ppp_nl_dellink, 1390 .get_size = ppp_nl_get_size, 1391 .fill_info = ppp_nl_fill_info, 1392 .get_link_net = ppp_nl_get_link_net, 1393 }; 1394 1395 #define PPP_MAJOR 108 1396 1397 /* Called at boot time if ppp is compiled into the kernel, 1398 or at module load time (from init_module) if compiled as a module. */ 1399 static int __init ppp_init(void) 1400 { 1401 int err; 1402 1403 pr_info("PPP generic driver version " PPP_VERSION "\n"); 1404 1405 err = register_pernet_device(&ppp_net_ops); 1406 if (err) { 1407 pr_err("failed to register PPP pernet device (%d)\n", err); 1408 goto out; 1409 } 1410 1411 err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops); 1412 if (err) { 1413 pr_err("failed to register PPP device (%d)\n", err); 1414 goto out_net; 1415 } 1416 1417 err = class_register(&ppp_class); 1418 if (err) 1419 goto out_chrdev; 1420 1421 err = rtnl_link_register(&ppp_link_ops); 1422 if (err) { 1423 pr_err("failed to register rtnetlink PPP handler\n"); 1424 goto out_class; 1425 } 1426 1427 /* not a big deal if we fail here :-) */ 1428 device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp"); 1429 1430 return 0; 1431 1432 out_class: 1433 class_unregister(&ppp_class); 1434 out_chrdev: 1435 unregister_chrdev(PPP_MAJOR, "ppp"); 1436 out_net: 1437 unregister_pernet_device(&ppp_net_ops); 1438 out: 1439 return err; 1440 } 1441 1442 /* 1443 * Network interface unit routines. 1444 */ 1445 static netdev_tx_t 1446 ppp_start_xmit(struct sk_buff *skb, struct net_device *dev) 1447 { 1448 struct ppp *ppp = netdev_priv(dev); 1449 int npi, proto; 1450 unsigned char *pp; 1451 1452 npi = ethertype_to_npindex(ntohs(skb->protocol)); 1453 if (npi < 0) 1454 goto outf; 1455 1456 /* Drop, accept or reject the packet */ 1457 switch (ppp->npmode[npi]) { 1458 case NPMODE_PASS: 1459 break; 1460 case NPMODE_QUEUE: 1461 /* it would be nice to have a way to tell the network 1462 system to queue this one up for later. */ 1463 goto outf; 1464 case NPMODE_DROP: 1465 case NPMODE_ERROR: 1466 goto outf; 1467 } 1468 1469 /* Put the 2-byte PPP protocol number on the front, 1470 making sure there is room for the address and control fields. */ 1471 if (skb_cow_head(skb, PPP_HDRLEN)) 1472 goto outf; 1473 1474 pp = skb_push(skb, 2); 1475 proto = npindex_to_proto[npi]; 1476 put_unaligned_be16(proto, pp); 1477 1478 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev))); 1479 ppp_xmit_process(ppp, skb); 1480 1481 return NETDEV_TX_OK; 1482 1483 outf: 1484 kfree_skb(skb); 1485 ++dev->stats.tx_dropped; 1486 return NETDEV_TX_OK; 1487 } 1488 1489 static int 1490 ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr, 1491 void __user *addr, int cmd) 1492 { 1493 struct ppp *ppp = netdev_priv(dev); 1494 int err = -EFAULT; 1495 struct ppp_stats stats; 1496 struct ppp_comp_stats cstats; 1497 char *vers; 1498 1499 switch (cmd) { 1500 case SIOCGPPPSTATS: 1501 ppp_get_stats(ppp, &stats); 1502 if (copy_to_user(addr, &stats, sizeof(stats))) 1503 break; 1504 err = 0; 1505 break; 1506 1507 case SIOCGPPPCSTATS: 1508 memset(&cstats, 0, sizeof(cstats)); 1509 if (ppp->xc_state) 1510 ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c); 1511 if (ppp->rc_state) 1512 ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d); 1513 if (copy_to_user(addr, &cstats, sizeof(cstats))) 1514 break; 1515 err = 0; 1516 break; 1517 1518 case SIOCGPPPVER: 1519 vers = PPP_VERSION; 1520 if (copy_to_user(addr, vers, strlen(vers) + 1)) 1521 break; 1522 err = 0; 1523 break; 1524 1525 default: 1526 err = -EINVAL; 1527 } 1528 1529 return err; 1530 } 1531 1532 static void 1533 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64) 1534 { 1535 struct ppp *ppp = netdev_priv(dev); 1536 1537 ppp_recv_lock(ppp); 1538 stats64->rx_packets = ppp->stats64.rx_packets; 1539 stats64->rx_bytes = ppp->stats64.rx_bytes; 1540 ppp_recv_unlock(ppp); 1541 1542 ppp_xmit_lock(ppp); 1543 stats64->tx_packets = ppp->stats64.tx_packets; 1544 stats64->tx_bytes = ppp->stats64.tx_bytes; 1545 ppp_xmit_unlock(ppp); 1546 1547 stats64->rx_errors = dev->stats.rx_errors; 1548 stats64->tx_errors = dev->stats.tx_errors; 1549 stats64->rx_dropped = dev->stats.rx_dropped; 1550 stats64->tx_dropped = dev->stats.tx_dropped; 1551 stats64->rx_length_errors = dev->stats.rx_length_errors; 1552 } 1553 1554 static int ppp_dev_init(struct net_device *dev) 1555 { 1556 struct ppp *ppp; 1557 1558 netdev_lockdep_set_classes(dev); 1559 1560 ppp = netdev_priv(dev); 1561 /* Let the netdevice take a reference on the ppp file. This ensures 1562 * that ppp_destroy_interface() won't run before the device gets 1563 * unregistered. 1564 */ 1565 refcount_inc(&ppp->file.refcnt); 1566 1567 return 0; 1568 } 1569 1570 static void ppp_dev_uninit(struct net_device *dev) 1571 { 1572 struct ppp *ppp = netdev_priv(dev); 1573 struct ppp_net *pn = ppp_pernet(ppp->ppp_net); 1574 1575 ppp_lock(ppp); 1576 ppp->closing = 1; 1577 ppp_unlock(ppp); 1578 1579 mutex_lock(&pn->all_ppp_mutex); 1580 unit_put(&pn->units_idr, ppp->file.index); 1581 mutex_unlock(&pn->all_ppp_mutex); 1582 1583 ppp->owner = NULL; 1584 1585 ppp->file.dead = 1; 1586 wake_up_interruptible(&ppp->file.rwait); 1587 } 1588 1589 static void ppp_dev_priv_destructor(struct net_device *dev) 1590 { 1591 struct ppp *ppp; 1592 1593 ppp = netdev_priv(dev); 1594 if (refcount_dec_and_test(&ppp->file.refcnt)) 1595 ppp_destroy_interface(ppp); 1596 } 1597 1598 static int ppp_fill_forward_path(struct net_device_path_ctx *ctx, 1599 struct net_device_path *path) 1600 { 1601 struct ppp *ppp = netdev_priv(ctx->dev); 1602 struct ppp_channel *chan; 1603 struct channel *pch; 1604 1605 if (ppp->flags & SC_MULTILINK) 1606 return -EOPNOTSUPP; 1607 1608 if (list_empty(&ppp->channels)) 1609 return -ENODEV; 1610 1611 pch = list_first_entry(&ppp->channels, struct channel, clist); 1612 chan = pch->chan; 1613 if (!chan->ops->fill_forward_path) 1614 return -EOPNOTSUPP; 1615 1616 return chan->ops->fill_forward_path(ctx, path, chan); 1617 } 1618 1619 static const struct net_device_ops ppp_netdev_ops = { 1620 .ndo_init = ppp_dev_init, 1621 .ndo_uninit = ppp_dev_uninit, 1622 .ndo_start_xmit = ppp_start_xmit, 1623 .ndo_siocdevprivate = ppp_net_siocdevprivate, 1624 .ndo_get_stats64 = ppp_get_stats64, 1625 .ndo_fill_forward_path = ppp_fill_forward_path, 1626 }; 1627 1628 static const struct device_type ppp_type = { 1629 .name = "ppp", 1630 }; 1631 1632 static void ppp_setup(struct net_device *dev) 1633 { 1634 dev->netdev_ops = &ppp_netdev_ops; 1635 SET_NETDEV_DEVTYPE(dev, &ppp_type); 1636 1637 dev->lltx = true; 1638 1639 dev->hard_header_len = PPP_HDRLEN; 1640 dev->mtu = PPP_MRU; 1641 dev->addr_len = 0; 1642 dev->tx_queue_len = 3; 1643 dev->type = ARPHRD_PPP; 1644 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 1645 dev->priv_destructor = ppp_dev_priv_destructor; 1646 netif_keep_dst(dev); 1647 } 1648 1649 /* 1650 * Transmit-side routines. 1651 */ 1652 1653 /* Called to do any work queued up on the transmit side that can now be done */ 1654 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1655 { 1656 ppp_xmit_lock(ppp); 1657 if (!ppp->closing) { 1658 ppp_push(ppp); 1659 1660 if (skb) 1661 skb_queue_tail(&ppp->file.xq, skb); 1662 while (!ppp->xmit_pending && 1663 (skb = skb_dequeue(&ppp->file.xq))) 1664 ppp_send_frame(ppp, skb); 1665 /* If there's no work left to do, tell the core net 1666 code that we can accept some more. */ 1667 if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq)) 1668 netif_wake_queue(ppp->dev); 1669 else 1670 netif_stop_queue(ppp->dev); 1671 } else { 1672 kfree_skb(skb); 1673 } 1674 ppp_xmit_unlock(ppp); 1675 } 1676 1677 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb) 1678 { 1679 local_bh_disable(); 1680 1681 if (unlikely(*this_cpu_ptr(ppp->xmit_recursion))) 1682 goto err; 1683 1684 (*this_cpu_ptr(ppp->xmit_recursion))++; 1685 __ppp_xmit_process(ppp, skb); 1686 (*this_cpu_ptr(ppp->xmit_recursion))--; 1687 1688 local_bh_enable(); 1689 1690 return; 1691 1692 err: 1693 local_bh_enable(); 1694 1695 kfree_skb(skb); 1696 1697 if (net_ratelimit()) 1698 netdev_err(ppp->dev, "recursion detected\n"); 1699 } 1700 1701 static inline struct sk_buff * 1702 pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) 1703 { 1704 struct sk_buff *new_skb; 1705 int len; 1706 int new_skb_size = ppp->dev->mtu + 1707 ppp->xcomp->comp_extra + ppp->dev->hard_header_len; 1708 int compressor_skb_size = ppp->dev->mtu + 1709 ppp->xcomp->comp_extra + PPP_HDRLEN; 1710 new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); 1711 if (!new_skb) { 1712 if (net_ratelimit()) 1713 netdev_err(ppp->dev, "PPP: no memory (comp pkt)\n"); 1714 return NULL; 1715 } 1716 if (ppp->dev->hard_header_len > PPP_HDRLEN) 1717 skb_reserve(new_skb, 1718 ppp->dev->hard_header_len - PPP_HDRLEN); 1719 1720 /* compressor still expects A/C bytes in hdr */ 1721 len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, 1722 new_skb->data, skb->len + 2, 1723 compressor_skb_size); 1724 if (len > 0 && (ppp->flags & SC_CCP_UP)) { 1725 consume_skb(skb); 1726 skb = new_skb; 1727 skb_put(skb, len); 1728 skb_pull(skb, 2); /* pull off A/C bytes */ 1729 } else if (len == 0) { 1730 /* didn't compress, or CCP not up yet */ 1731 consume_skb(new_skb); 1732 new_skb = skb; 1733 } else { 1734 /* 1735 * (len < 0) 1736 * MPPE requires that we do not send unencrypted 1737 * frames. The compressor will return -1 if we 1738 * should drop the frame. We cannot simply test 1739 * the compress_proto because MPPE and MPPC share 1740 * the same number. 1741 */ 1742 if (net_ratelimit()) 1743 netdev_err(ppp->dev, "ppp: compressor dropped pkt\n"); 1744 kfree_skb(skb); 1745 consume_skb(new_skb); 1746 new_skb = NULL; 1747 } 1748 return new_skb; 1749 } 1750 1751 /* 1752 * Compress and send a frame. 1753 * The caller should have locked the xmit path, 1754 * and xmit_pending should be 0. 1755 */ 1756 static void 1757 ppp_send_frame(struct ppp *ppp, struct sk_buff *skb) 1758 { 1759 int proto = PPP_PROTO(skb); 1760 struct sk_buff *new_skb; 1761 int len; 1762 unsigned char *cp; 1763 1764 skb->dev = ppp->dev; 1765 1766 if (proto < 0x8000) { 1767 #ifdef CONFIG_PPP_FILTER 1768 /* check if we should pass this packet */ 1769 /* the filter instructions are constructed assuming 1770 a four-byte PPP header on each packet */ 1771 *(u8 *)skb_push(skb, 2) = 1; 1772 if (ppp->pass_filter && 1773 bpf_prog_run(ppp->pass_filter, skb) == 0) { 1774 if (ppp->debug & 1) 1775 netdev_printk(KERN_DEBUG, ppp->dev, 1776 "PPP: outbound frame " 1777 "not passed\n"); 1778 kfree_skb(skb); 1779 return; 1780 } 1781 /* if this packet passes the active filter, record the time */ 1782 if (!(ppp->active_filter && 1783 bpf_prog_run(ppp->active_filter, skb) == 0)) 1784 ppp->last_xmit = jiffies; 1785 skb_pull(skb, 2); 1786 #else 1787 /* for data packets, record the time */ 1788 ppp->last_xmit = jiffies; 1789 #endif /* CONFIG_PPP_FILTER */ 1790 } 1791 1792 ++ppp->stats64.tx_packets; 1793 ppp->stats64.tx_bytes += skb->len - PPP_PROTO_LEN; 1794 1795 switch (proto) { 1796 case PPP_IP: 1797 if (!ppp->vj || (ppp->flags & SC_COMP_TCP) == 0) 1798 break; 1799 /* try to do VJ TCP header compression */ 1800 new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2, 1801 GFP_ATOMIC); 1802 if (!new_skb) { 1803 netdev_err(ppp->dev, "PPP: no memory (VJ comp pkt)\n"); 1804 goto drop; 1805 } 1806 skb_reserve(new_skb, ppp->dev->hard_header_len - 2); 1807 cp = skb->data + 2; 1808 len = slhc_compress(ppp->vj, cp, skb->len - 2, 1809 new_skb->data + 2, &cp, 1810 !(ppp->flags & SC_NO_TCP_CCID)); 1811 if (cp == skb->data + 2) { 1812 /* didn't compress */ 1813 consume_skb(new_skb); 1814 } else { 1815 if (cp[0] & SL_TYPE_COMPRESSED_TCP) { 1816 proto = PPP_VJC_COMP; 1817 cp[0] &= ~SL_TYPE_COMPRESSED_TCP; 1818 } else { 1819 proto = PPP_VJC_UNCOMP; 1820 cp[0] = skb->data[2]; 1821 } 1822 consume_skb(skb); 1823 skb = new_skb; 1824 cp = skb_put(skb, len + 2); 1825 cp[0] = 0; 1826 cp[1] = proto; 1827 } 1828 break; 1829 1830 case PPP_CCP: 1831 /* peek at outbound CCP frames */ 1832 ppp_ccp_peek(ppp, skb, 0); 1833 break; 1834 } 1835 1836 /* try to do packet compression */ 1837 if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state && 1838 proto != PPP_LCP && proto != PPP_CCP) { 1839 if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) { 1840 if (net_ratelimit()) 1841 netdev_err(ppp->dev, 1842 "ppp: compression required but " 1843 "down - pkt dropped.\n"); 1844 goto drop; 1845 } 1846 skb = pad_compress_skb(ppp, skb); 1847 if (!skb) 1848 goto drop; 1849 } 1850 1851 /* 1852 * If we are waiting for traffic (demand dialling), 1853 * queue it up for pppd to receive. 1854 */ 1855 if (ppp->flags & SC_LOOP_TRAFFIC) { 1856 if (ppp->file.rq.qlen > PPP_MAX_RQLEN) 1857 goto drop; 1858 skb_queue_tail(&ppp->file.rq, skb); 1859 wake_up_interruptible(&ppp->file.rwait); 1860 return; 1861 } 1862 1863 ppp->xmit_pending = skb; 1864 ppp_push(ppp); 1865 return; 1866 1867 drop: 1868 kfree_skb(skb); 1869 ++ppp->dev->stats.tx_errors; 1870 } 1871 1872 /* 1873 * Try to send the frame in xmit_pending. 1874 * The caller should have the xmit path locked. 1875 */ 1876 static void 1877 ppp_push(struct ppp *ppp) 1878 { 1879 struct list_head *list; 1880 struct channel *pch; 1881 struct sk_buff *skb = ppp->xmit_pending; 1882 1883 if (!skb) 1884 return; 1885 1886 list = &ppp->channels; 1887 if (list_empty(list)) { 1888 /* nowhere to send the packet, just drop it */ 1889 ppp->xmit_pending = NULL; 1890 kfree_skb(skb); 1891 return; 1892 } 1893 1894 if ((ppp->flags & SC_MULTILINK) == 0) { 1895 /* not doing multilink: send it down the first channel */ 1896 list = list->next; 1897 pch = list_entry(list, struct channel, clist); 1898 1899 spin_lock(&pch->downl); 1900 if (pch->chan) { 1901 if (pch->chan->ops->start_xmit(pch->chan, skb)) 1902 ppp->xmit_pending = NULL; 1903 } else { 1904 /* channel got unregistered */ 1905 kfree_skb(skb); 1906 ppp->xmit_pending = NULL; 1907 } 1908 spin_unlock(&pch->downl); 1909 return; 1910 } 1911 1912 #ifdef CONFIG_PPP_MULTILINK 1913 /* Multilink: fragment the packet over as many links 1914 as can take the packet at the moment. */ 1915 if (!ppp_mp_explode(ppp, skb)) 1916 return; 1917 #endif /* CONFIG_PPP_MULTILINK */ 1918 1919 ppp->xmit_pending = NULL; 1920 kfree_skb(skb); 1921 } 1922 1923 #ifdef CONFIG_PPP_MULTILINK 1924 static bool mp_protocol_compress __read_mostly = true; 1925 module_param(mp_protocol_compress, bool, 0644); 1926 MODULE_PARM_DESC(mp_protocol_compress, 1927 "compress protocol id in multilink fragments"); 1928 1929 /* 1930 * Divide a packet to be transmitted into fragments and 1931 * send them out the individual links. 1932 */ 1933 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb) 1934 { 1935 int len, totlen; 1936 int i, bits, hdrlen, mtu; 1937 int flen; 1938 int navail, nfree, nzero; 1939 int nbigger; 1940 int totspeed; 1941 int totfree; 1942 unsigned char *p, *q; 1943 struct list_head *list; 1944 struct channel *pch; 1945 struct sk_buff *frag; 1946 struct ppp_channel *chan; 1947 1948 totspeed = 0; /*total bitrate of the bundle*/ 1949 nfree = 0; /* # channels which have no packet already queued */ 1950 navail = 0; /* total # of usable channels (not deregistered) */ 1951 nzero = 0; /* number of channels with zero speed associated*/ 1952 totfree = 0; /*total # of channels available and 1953 *having no queued packets before 1954 *starting the fragmentation*/ 1955 1956 hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 1957 i = 0; 1958 list_for_each_entry(pch, &ppp->channels, clist) { 1959 if (pch->chan) { 1960 pch->avail = 1; 1961 navail++; 1962 pch->speed = pch->chan->speed; 1963 } else { 1964 pch->avail = 0; 1965 } 1966 if (pch->avail) { 1967 if (skb_queue_empty(&pch->file.xq) || 1968 !pch->had_frag) { 1969 if (pch->speed == 0) 1970 nzero++; 1971 else 1972 totspeed += pch->speed; 1973 1974 pch->avail = 2; 1975 ++nfree; 1976 ++totfree; 1977 } 1978 if (!pch->had_frag && i < ppp->nxchan) 1979 ppp->nxchan = i; 1980 } 1981 ++i; 1982 } 1983 /* 1984 * Don't start sending this packet unless at least half of 1985 * the channels are free. This gives much better TCP 1986 * performance if we have a lot of channels. 1987 */ 1988 if (nfree == 0 || nfree < navail / 2) 1989 return 0; /* can't take now, leave it in xmit_pending */ 1990 1991 /* Do protocol field compression */ 1992 p = skb->data; 1993 len = skb->len; 1994 if (*p == 0 && mp_protocol_compress) { 1995 ++p; 1996 --len; 1997 } 1998 1999 totlen = len; 2000 nbigger = len % nfree; 2001 2002 /* skip to the channel after the one we last used 2003 and start at that one */ 2004 list = &ppp->channels; 2005 for (i = 0; i < ppp->nxchan; ++i) { 2006 list = list->next; 2007 if (list == &ppp->channels) { 2008 i = 0; 2009 break; 2010 } 2011 } 2012 2013 /* create a fragment for each channel */ 2014 bits = B; 2015 while (len > 0) { 2016 list = list->next; 2017 if (list == &ppp->channels) { 2018 i = 0; 2019 continue; 2020 } 2021 pch = list_entry(list, struct channel, clist); 2022 ++i; 2023 if (!pch->avail) 2024 continue; 2025 2026 /* 2027 * Skip this channel if it has a fragment pending already and 2028 * we haven't given a fragment to all of the free channels. 2029 */ 2030 if (pch->avail == 1) { 2031 if (nfree > 0) 2032 continue; 2033 } else { 2034 pch->avail = 1; 2035 } 2036 2037 /* check the channel's mtu and whether it is still attached. */ 2038 spin_lock(&pch->downl); 2039 if (pch->chan == NULL) { 2040 /* can't use this channel, it's being deregistered */ 2041 if (pch->speed == 0) 2042 nzero--; 2043 else 2044 totspeed -= pch->speed; 2045 2046 spin_unlock(&pch->downl); 2047 pch->avail = 0; 2048 totlen = len; 2049 totfree--; 2050 nfree--; 2051 if (--navail == 0) 2052 break; 2053 continue; 2054 } 2055 2056 /* 2057 *if the channel speed is not set divide 2058 *the packet evenly among the free channels; 2059 *otherwise divide it according to the speed 2060 *of the channel we are going to transmit on 2061 */ 2062 flen = len; 2063 if (nfree > 0) { 2064 if (pch->speed == 0) { 2065 flen = len/nfree; 2066 if (nbigger > 0) { 2067 flen++; 2068 nbigger--; 2069 } 2070 } else { 2071 flen = (((totfree - nzero)*(totlen + hdrlen*totfree)) / 2072 ((totspeed*totfree)/pch->speed)) - hdrlen; 2073 if (nbigger > 0) { 2074 flen += ((totfree - nzero)*pch->speed)/totspeed; 2075 nbigger -= ((totfree - nzero)*pch->speed)/ 2076 totspeed; 2077 } 2078 } 2079 nfree--; 2080 } 2081 2082 /* 2083 *check if we are on the last channel or 2084 *we exceded the length of the data to 2085 *fragment 2086 */ 2087 if ((nfree <= 0) || (flen > len)) 2088 flen = len; 2089 /* 2090 *it is not worth to tx on slow channels: 2091 *in that case from the resulting flen according to the 2092 *above formula will be equal or less than zero. 2093 *Skip the channel in this case 2094 */ 2095 if (flen <= 0) { 2096 pch->avail = 2; 2097 spin_unlock(&pch->downl); 2098 continue; 2099 } 2100 2101 /* 2102 * hdrlen includes the 2-byte PPP protocol field, but the 2103 * MTU counts only the payload excluding the protocol field. 2104 * (RFC1661 Section 2) 2105 */ 2106 mtu = pch->chan->mtu - (hdrlen - 2); 2107 if (mtu < 4) 2108 mtu = 4; 2109 if (flen > mtu) 2110 flen = mtu; 2111 if (flen == len) 2112 bits |= E; 2113 frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC); 2114 if (!frag) 2115 goto noskb; 2116 q = skb_put(frag, flen + hdrlen); 2117 2118 /* make the MP header */ 2119 put_unaligned_be16(PPP_MP, q); 2120 if (ppp->flags & SC_MP_XSHORTSEQ) { 2121 q[2] = bits + ((ppp->nxseq >> 8) & 0xf); 2122 q[3] = ppp->nxseq; 2123 } else { 2124 q[2] = bits; 2125 q[3] = ppp->nxseq >> 16; 2126 q[4] = ppp->nxseq >> 8; 2127 q[5] = ppp->nxseq; 2128 } 2129 2130 memcpy(q + hdrlen, p, flen); 2131 2132 /* try to send it down the channel */ 2133 chan = pch->chan; 2134 if (!skb_queue_empty(&pch->file.xq) || 2135 !chan->ops->start_xmit(chan, frag)) 2136 skb_queue_tail(&pch->file.xq, frag); 2137 pch->had_frag = 1; 2138 p += flen; 2139 len -= flen; 2140 ++ppp->nxseq; 2141 bits = 0; 2142 spin_unlock(&pch->downl); 2143 } 2144 ppp->nxchan = i; 2145 2146 return 1; 2147 2148 noskb: 2149 spin_unlock(&pch->downl); 2150 if (ppp->debug & 1) 2151 netdev_err(ppp->dev, "PPP: no memory (fragment)\n"); 2152 ++ppp->dev->stats.tx_errors; 2153 ++ppp->nxseq; 2154 return 1; /* abandon the frame */ 2155 } 2156 #endif /* CONFIG_PPP_MULTILINK */ 2157 2158 /* Try to send data out on a channel */ 2159 static void __ppp_channel_push(struct channel *pch) 2160 { 2161 struct sk_buff *skb; 2162 struct ppp *ppp; 2163 2164 spin_lock(&pch->downl); 2165 if (pch->chan) { 2166 while (!skb_queue_empty(&pch->file.xq)) { 2167 skb = skb_dequeue(&pch->file.xq); 2168 if (!pch->chan->ops->start_xmit(pch->chan, skb)) { 2169 /* put the packet back and try again later */ 2170 skb_queue_head(&pch->file.xq, skb); 2171 break; 2172 } 2173 } 2174 } else { 2175 /* channel got deregistered */ 2176 skb_queue_purge(&pch->file.xq); 2177 } 2178 spin_unlock(&pch->downl); 2179 /* see if there is anything from the attached unit to be sent */ 2180 if (skb_queue_empty(&pch->file.xq)) { 2181 ppp = pch->ppp; 2182 if (ppp) 2183 __ppp_xmit_process(ppp, NULL); 2184 } 2185 } 2186 2187 static void ppp_channel_push(struct channel *pch) 2188 { 2189 read_lock_bh(&pch->upl); 2190 if (pch->ppp) { 2191 (*this_cpu_ptr(pch->ppp->xmit_recursion))++; 2192 __ppp_channel_push(pch); 2193 (*this_cpu_ptr(pch->ppp->xmit_recursion))--; 2194 } else { 2195 __ppp_channel_push(pch); 2196 } 2197 read_unlock_bh(&pch->upl); 2198 } 2199 2200 /* 2201 * Receive-side routines. 2202 */ 2203 2204 struct ppp_mp_skb_parm { 2205 u32 sequence; 2206 u8 BEbits; 2207 }; 2208 #define PPP_MP_CB(skb) ((struct ppp_mp_skb_parm *)((skb)->cb)) 2209 2210 static inline void 2211 ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2212 { 2213 ppp_recv_lock(ppp); 2214 if (!ppp->closing) 2215 ppp_receive_frame(ppp, skb, pch); 2216 else 2217 kfree_skb(skb); 2218 ppp_recv_unlock(ppp); 2219 } 2220 2221 /** 2222 * __ppp_decompress_proto - Decompress protocol field, slim version. 2223 * @skb: Socket buffer where protocol field should be decompressed. It must have 2224 * at least 1 byte of head room and 1 byte of linear data. First byte of 2225 * data must be a protocol field byte. 2226 * 2227 * Decompress protocol field in PPP header if it's compressed, e.g. when 2228 * Protocol-Field-Compression (PFC) was negotiated. No checks w.r.t. skb data 2229 * length are done in this function. 2230 */ 2231 static void __ppp_decompress_proto(struct sk_buff *skb) 2232 { 2233 if (skb->data[0] & 0x01) 2234 *(u8 *)skb_push(skb, 1) = 0x00; 2235 } 2236 2237 /** 2238 * ppp_decompress_proto - Check skb data room and decompress protocol field. 2239 * @skb: Socket buffer where protocol field should be decompressed. First byte 2240 * of data must be a protocol field byte. 2241 * 2242 * Decompress protocol field in PPP header if it's compressed, e.g. when 2243 * Protocol-Field-Compression (PFC) was negotiated. This function also makes 2244 * sure that skb data room is sufficient for Protocol field, before and after 2245 * decompression. 2246 * 2247 * Return: true - decompressed successfully, false - not enough room in skb. 2248 */ 2249 static bool ppp_decompress_proto(struct sk_buff *skb) 2250 { 2251 /* At least one byte should be present (if protocol is compressed) */ 2252 if (!pskb_may_pull(skb, 1)) 2253 return false; 2254 2255 __ppp_decompress_proto(skb); 2256 2257 /* Protocol field should occupy 2 bytes when not compressed */ 2258 return pskb_may_pull(skb, 2); 2259 } 2260 2261 /* Attempt to handle a frame via. a bridged channel, if one exists. 2262 * If the channel is bridged, the frame is consumed by the bridge. 2263 * If not, the caller must handle the frame by normal recv mechanisms. 2264 * Returns true if the frame is consumed, false otherwise. 2265 */ 2266 static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb) 2267 { 2268 struct channel *pchb; 2269 2270 rcu_read_lock(); 2271 pchb = rcu_dereference(pch->bridge); 2272 if (!pchb) 2273 goto out_rcu; 2274 2275 spin_lock_bh(&pchb->downl); 2276 if (!pchb->chan) { 2277 /* channel got unregistered */ 2278 kfree_skb(skb); 2279 goto outl; 2280 } 2281 2282 skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net)); 2283 if (!pchb->chan->ops->start_xmit(pchb->chan, skb)) 2284 kfree_skb(skb); 2285 2286 outl: 2287 spin_unlock_bh(&pchb->downl); 2288 out_rcu: 2289 rcu_read_unlock(); 2290 2291 /* If pchb is set then we've consumed the packet */ 2292 return !!pchb; 2293 } 2294 2295 void 2296 ppp_input(struct ppp_channel *chan, struct sk_buff *skb) 2297 { 2298 struct channel *pch = chan->ppp; 2299 int proto; 2300 2301 if (!pch) { 2302 kfree_skb(skb); 2303 return; 2304 } 2305 2306 /* If the channel is bridged, transmit via. bridge */ 2307 if (ppp_channel_bridge_input(pch, skb)) 2308 return; 2309 2310 read_lock_bh(&pch->upl); 2311 if (!ppp_decompress_proto(skb)) { 2312 kfree_skb(skb); 2313 if (pch->ppp) { 2314 ++pch->ppp->dev->stats.rx_length_errors; 2315 ppp_receive_error(pch->ppp); 2316 } 2317 goto done; 2318 } 2319 2320 proto = PPP_PROTO(skb); 2321 if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) { 2322 /* put it on the channel queue */ 2323 skb_queue_tail(&pch->file.rq, skb); 2324 /* drop old frames if queue too long */ 2325 while (pch->file.rq.qlen > PPP_MAX_RQLEN && 2326 (skb = skb_dequeue(&pch->file.rq))) 2327 kfree_skb(skb); 2328 wake_up_interruptible(&pch->file.rwait); 2329 } else { 2330 ppp_do_recv(pch->ppp, skb, pch); 2331 } 2332 2333 done: 2334 read_unlock_bh(&pch->upl); 2335 } 2336 2337 /* Put a 0-length skb in the receive queue as an error indication */ 2338 void 2339 ppp_input_error(struct ppp_channel *chan, int code) 2340 { 2341 struct channel *pch = chan->ppp; 2342 struct sk_buff *skb; 2343 2344 if (!pch) 2345 return; 2346 2347 read_lock_bh(&pch->upl); 2348 if (pch->ppp) { 2349 skb = alloc_skb(0, GFP_ATOMIC); 2350 if (skb) { 2351 skb->len = 0; /* probably unnecessary */ 2352 skb->cb[0] = code; 2353 ppp_do_recv(pch->ppp, skb, pch); 2354 } 2355 } 2356 read_unlock_bh(&pch->upl); 2357 } 2358 2359 /* 2360 * We come in here to process a received frame. 2361 * The receive side of the ppp unit is locked. 2362 */ 2363 static void 2364 ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2365 { 2366 /* note: a 0-length skb is used as an error indication */ 2367 if (skb->len > 0) { 2368 skb_checksum_complete_unset(skb); 2369 #ifdef CONFIG_PPP_MULTILINK 2370 /* XXX do channel-level decompression here */ 2371 if (PPP_PROTO(skb) == PPP_MP) 2372 ppp_receive_mp_frame(ppp, skb, pch); 2373 else 2374 #endif /* CONFIG_PPP_MULTILINK */ 2375 ppp_receive_nonmp_frame(ppp, skb); 2376 } else { 2377 kfree_skb(skb); 2378 ppp_receive_error(ppp); 2379 } 2380 } 2381 2382 static void 2383 ppp_receive_error(struct ppp *ppp) 2384 { 2385 ++ppp->dev->stats.rx_errors; 2386 if (ppp->vj) 2387 slhc_toss(ppp->vj); 2388 } 2389 2390 static void 2391 ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb) 2392 { 2393 struct sk_buff *ns; 2394 int proto, len, npi; 2395 2396 /* 2397 * Decompress the frame, if compressed. 2398 * Note that some decompressors need to see uncompressed frames 2399 * that come in as well as compressed frames. 2400 */ 2401 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN) && 2402 (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0) 2403 skb = ppp_decompress_frame(ppp, skb); 2404 2405 if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR) 2406 goto err; 2407 2408 /* At this point the "Protocol" field MUST be decompressed, either in 2409 * ppp_input(), ppp_decompress_frame() or in ppp_receive_mp_frame(). 2410 */ 2411 proto = PPP_PROTO(skb); 2412 switch (proto) { 2413 case PPP_VJC_COMP: 2414 /* decompress VJ compressed packets */ 2415 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2416 goto err; 2417 2418 if (skb_tailroom(skb) < 124 || skb_cloned(skb)) { 2419 /* copy to a new sk_buff with more tailroom */ 2420 ns = dev_alloc_skb(skb->len + 128); 2421 if (!ns) { 2422 netdev_err(ppp->dev, "PPP: no memory " 2423 "(VJ decomp)\n"); 2424 goto err; 2425 } 2426 skb_reserve(ns, 2); 2427 skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); 2428 consume_skb(skb); 2429 skb = ns; 2430 } 2431 else 2432 skb->ip_summed = CHECKSUM_NONE; 2433 2434 len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2); 2435 if (len <= 0) { 2436 netdev_printk(KERN_DEBUG, ppp->dev, 2437 "PPP: VJ decompression error\n"); 2438 goto err; 2439 } 2440 len += 2; 2441 if (len > skb->len) 2442 skb_put(skb, len - skb->len); 2443 else if (len < skb->len) 2444 skb_trim(skb, len); 2445 proto = PPP_IP; 2446 break; 2447 2448 case PPP_VJC_UNCOMP: 2449 if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP)) 2450 goto err; 2451 2452 /* Until we fix the decompressor need to make sure 2453 * data portion is linear. 2454 */ 2455 if (!pskb_may_pull(skb, skb->len)) 2456 goto err; 2457 2458 if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) { 2459 netdev_err(ppp->dev, "PPP: VJ uncompressed error\n"); 2460 goto err; 2461 } 2462 proto = PPP_IP; 2463 break; 2464 2465 case PPP_CCP: 2466 ppp_ccp_peek(ppp, skb, 1); 2467 break; 2468 } 2469 2470 ++ppp->stats64.rx_packets; 2471 ppp->stats64.rx_bytes += skb->len - 2; 2472 2473 npi = proto_to_npindex(proto); 2474 if (npi < 0) { 2475 /* control or unknown frame - pass it to pppd */ 2476 skb_queue_tail(&ppp->file.rq, skb); 2477 /* limit queue length by dropping old frames */ 2478 while (ppp->file.rq.qlen > PPP_MAX_RQLEN && 2479 (skb = skb_dequeue(&ppp->file.rq))) 2480 kfree_skb(skb); 2481 /* wake up any process polling or blocking on read */ 2482 wake_up_interruptible(&ppp->file.rwait); 2483 2484 } else { 2485 /* network protocol frame - give it to the kernel */ 2486 2487 #ifdef CONFIG_PPP_FILTER 2488 /* check if the packet passes the pass and active filters */ 2489 /* the filter instructions are constructed assuming 2490 a four-byte PPP header on each packet */ 2491 if (ppp->pass_filter || ppp->active_filter) { 2492 if (skb_unclone(skb, GFP_ATOMIC)) 2493 goto err; 2494 2495 *(u8 *)skb_push(skb, 2) = 0; 2496 if (ppp->pass_filter && 2497 bpf_prog_run(ppp->pass_filter, skb) == 0) { 2498 if (ppp->debug & 1) 2499 netdev_printk(KERN_DEBUG, ppp->dev, 2500 "PPP: inbound frame " 2501 "not passed\n"); 2502 kfree_skb(skb); 2503 return; 2504 } 2505 if (!(ppp->active_filter && 2506 bpf_prog_run(ppp->active_filter, skb) == 0)) 2507 ppp->last_recv = jiffies; 2508 __skb_pull(skb, 2); 2509 } else 2510 #endif /* CONFIG_PPP_FILTER */ 2511 ppp->last_recv = jiffies; 2512 2513 if ((ppp->dev->flags & IFF_UP) == 0 || 2514 ppp->npmode[npi] != NPMODE_PASS) { 2515 kfree_skb(skb); 2516 } else { 2517 /* chop off protocol */ 2518 skb_pull_rcsum(skb, 2); 2519 skb->dev = ppp->dev; 2520 skb->protocol = htons(npindex_to_ethertype[npi]); 2521 skb_reset_mac_header(skb); 2522 skb_scrub_packet(skb, !net_eq(ppp->ppp_net, 2523 dev_net(ppp->dev))); 2524 netif_rx(skb); 2525 } 2526 } 2527 return; 2528 2529 err: 2530 kfree_skb(skb); 2531 ppp_receive_error(ppp); 2532 } 2533 2534 static struct sk_buff * 2535 ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb) 2536 { 2537 int proto = PPP_PROTO(skb); 2538 struct sk_buff *ns; 2539 int len; 2540 2541 /* Until we fix all the decompressor's need to make sure 2542 * data portion is linear. 2543 */ 2544 if (!pskb_may_pull(skb, skb->len)) 2545 goto err; 2546 2547 if (proto == PPP_COMP) { 2548 int obuff_size; 2549 2550 switch(ppp->rcomp->compress_proto) { 2551 case CI_MPPE: 2552 obuff_size = ppp->mru + PPP_HDRLEN + 1; 2553 break; 2554 default: 2555 obuff_size = ppp->mru + PPP_HDRLEN; 2556 break; 2557 } 2558 2559 ns = dev_alloc_skb(obuff_size); 2560 if (!ns) { 2561 netdev_err(ppp->dev, "ppp_decompress_frame: " 2562 "no memory\n"); 2563 goto err; 2564 } 2565 /* the decompressor still expects the A/C bytes in the hdr */ 2566 len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2, 2567 skb->len + 2, ns->data, obuff_size); 2568 if (len < 0) { 2569 /* Pass the compressed frame to pppd as an 2570 error indication. */ 2571 if (len == DECOMP_FATALERROR) 2572 ppp->rstate |= SC_DC_FERROR; 2573 kfree_skb(ns); 2574 goto err; 2575 } 2576 2577 consume_skb(skb); 2578 skb = ns; 2579 skb_put(skb, len); 2580 skb_pull(skb, 2); /* pull off the A/C bytes */ 2581 2582 /* Don't call __ppp_decompress_proto() here, but instead rely on 2583 * corresponding algo (mppe/bsd/deflate) to decompress it. 2584 */ 2585 } else { 2586 /* Uncompressed frame - pass to decompressor so it 2587 can update its dictionary if necessary. */ 2588 if (ppp->rcomp->incomp) 2589 ppp->rcomp->incomp(ppp->rc_state, skb->data - 2, 2590 skb->len + 2); 2591 } 2592 2593 return skb; 2594 2595 err: 2596 ppp->rstate |= SC_DC_ERROR; 2597 ppp_receive_error(ppp); 2598 return skb; 2599 } 2600 2601 #ifdef CONFIG_PPP_MULTILINK 2602 /* 2603 * Receive a multilink frame. 2604 * We put it on the reconstruction queue and then pull off 2605 * as many completed frames as we can. 2606 */ 2607 static void 2608 ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) 2609 { 2610 u32 mask, seq; 2611 struct channel *ch; 2612 int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; 2613 2614 if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0) 2615 goto err; /* no good, throw it away */ 2616 2617 /* Decode sequence number and begin/end bits */ 2618 if (ppp->flags & SC_MP_SHORTSEQ) { 2619 seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3]; 2620 mask = 0xfff; 2621 } else { 2622 seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5]; 2623 mask = 0xffffff; 2624 } 2625 PPP_MP_CB(skb)->BEbits = skb->data[2]; 2626 skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */ 2627 2628 /* 2629 * Do protocol ID decompression on the first fragment of each packet. 2630 * We have to do that here, because ppp_receive_nonmp_frame() expects 2631 * decompressed protocol field. 2632 */ 2633 if (PPP_MP_CB(skb)->BEbits & B) 2634 __ppp_decompress_proto(skb); 2635 2636 /* 2637 * Expand sequence number to 32 bits, making it as close 2638 * as possible to ppp->minseq. 2639 */ 2640 seq |= ppp->minseq & ~mask; 2641 if ((int)(ppp->minseq - seq) > (int)(mask >> 1)) 2642 seq += mask + 1; 2643 else if ((int)(seq - ppp->minseq) > (int)(mask >> 1)) 2644 seq -= mask + 1; /* should never happen */ 2645 PPP_MP_CB(skb)->sequence = seq; 2646 pch->lastseq = seq; 2647 2648 /* 2649 * If this packet comes before the next one we were expecting, 2650 * drop it. 2651 */ 2652 if (seq_before(seq, ppp->nextseq)) { 2653 kfree_skb(skb); 2654 ++ppp->dev->stats.rx_dropped; 2655 ppp_receive_error(ppp); 2656 return; 2657 } 2658 2659 /* 2660 * Reevaluate minseq, the minimum over all channels of the 2661 * last sequence number received on each channel. Because of 2662 * the increasing sequence number rule, we know that any fragment 2663 * before `minseq' which hasn't arrived is never going to arrive. 2664 * The list of channels can't change because we have the receive 2665 * side of the ppp unit locked. 2666 */ 2667 list_for_each_entry(ch, &ppp->channels, clist) { 2668 if (seq_before(ch->lastseq, seq)) 2669 seq = ch->lastseq; 2670 } 2671 if (seq_before(ppp->minseq, seq)) 2672 ppp->minseq = seq; 2673 2674 /* Put the fragment on the reconstruction queue */ 2675 ppp_mp_insert(ppp, skb); 2676 2677 /* If the queue is getting long, don't wait any longer for packets 2678 before the start of the queue. */ 2679 if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN) { 2680 struct sk_buff *mskb = skb_peek(&ppp->mrq); 2681 if (seq_before(ppp->minseq, PPP_MP_CB(mskb)->sequence)) 2682 ppp->minseq = PPP_MP_CB(mskb)->sequence; 2683 } 2684 2685 /* Pull completed packets off the queue and receive them. */ 2686 while ((skb = ppp_mp_reconstruct(ppp))) { 2687 if (pskb_may_pull(skb, 2)) 2688 ppp_receive_nonmp_frame(ppp, skb); 2689 else { 2690 ++ppp->dev->stats.rx_length_errors; 2691 kfree_skb(skb); 2692 ppp_receive_error(ppp); 2693 } 2694 } 2695 2696 return; 2697 2698 err: 2699 kfree_skb(skb); 2700 ppp_receive_error(ppp); 2701 } 2702 2703 /* 2704 * Insert a fragment on the MP reconstruction queue. 2705 * The queue is ordered by increasing sequence number. 2706 */ 2707 static void 2708 ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb) 2709 { 2710 struct sk_buff *p; 2711 struct sk_buff_head *list = &ppp->mrq; 2712 u32 seq = PPP_MP_CB(skb)->sequence; 2713 2714 /* N.B. we don't need to lock the list lock because we have the 2715 ppp unit receive-side lock. */ 2716 skb_queue_walk(list, p) { 2717 if (seq_before(seq, PPP_MP_CB(p)->sequence)) 2718 break; 2719 } 2720 __skb_queue_before(list, p, skb); 2721 } 2722 2723 /* 2724 * Reconstruct a packet from the MP fragment queue. 2725 * We go through increasing sequence numbers until we find a 2726 * complete packet, or we get to the sequence number for a fragment 2727 * which hasn't arrived but might still do so. 2728 */ 2729 static struct sk_buff * 2730 ppp_mp_reconstruct(struct ppp *ppp) 2731 { 2732 u32 seq = ppp->nextseq; 2733 u32 minseq = ppp->minseq; 2734 struct sk_buff_head *list = &ppp->mrq; 2735 struct sk_buff *p, *tmp; 2736 struct sk_buff *head, *tail; 2737 struct sk_buff *skb = NULL; 2738 int lost = 0, len = 0; 2739 2740 if (ppp->mrru == 0) /* do nothing until mrru is set */ 2741 return NULL; 2742 head = __skb_peek(list); 2743 tail = NULL; 2744 skb_queue_walk_safe(list, p, tmp) { 2745 again: 2746 if (seq_before(PPP_MP_CB(p)->sequence, seq)) { 2747 /* this can't happen, anyway ignore the skb */ 2748 netdev_err(ppp->dev, "ppp_mp_reconstruct bad " 2749 "seq %u < %u\n", 2750 PPP_MP_CB(p)->sequence, seq); 2751 __skb_unlink(p, list); 2752 kfree_skb(p); 2753 continue; 2754 } 2755 if (PPP_MP_CB(p)->sequence != seq) { 2756 u32 oldseq; 2757 /* Fragment `seq' is missing. If it is after 2758 minseq, it might arrive later, so stop here. */ 2759 if (seq_after(seq, minseq)) 2760 break; 2761 /* Fragment `seq' is lost, keep going. */ 2762 lost = 1; 2763 oldseq = seq; 2764 seq = seq_before(minseq, PPP_MP_CB(p)->sequence)? 2765 minseq + 1: PPP_MP_CB(p)->sequence; 2766 2767 if (ppp->debug & 1) 2768 netdev_printk(KERN_DEBUG, ppp->dev, 2769 "lost frag %u..%u\n", 2770 oldseq, seq-1); 2771 2772 goto again; 2773 } 2774 2775 /* 2776 * At this point we know that all the fragments from 2777 * ppp->nextseq to seq are either present or lost. 2778 * Also, there are no complete packets in the queue 2779 * that have no missing fragments and end before this 2780 * fragment. 2781 */ 2782 2783 /* B bit set indicates this fragment starts a packet */ 2784 if (PPP_MP_CB(p)->BEbits & B) { 2785 head = p; 2786 lost = 0; 2787 len = 0; 2788 } 2789 2790 len += p->len; 2791 2792 /* Got a complete packet yet? */ 2793 if (lost == 0 && (PPP_MP_CB(p)->BEbits & E) && 2794 (PPP_MP_CB(head)->BEbits & B)) { 2795 if (len > ppp->mrru + 2) { 2796 ++ppp->dev->stats.rx_length_errors; 2797 netdev_printk(KERN_DEBUG, ppp->dev, 2798 "PPP: reconstructed packet" 2799 " is too long (%d)\n", len); 2800 } else { 2801 tail = p; 2802 break; 2803 } 2804 ppp->nextseq = seq + 1; 2805 } 2806 2807 /* 2808 * If this is the ending fragment of a packet, 2809 * and we haven't found a complete valid packet yet, 2810 * we can discard up to and including this fragment. 2811 */ 2812 if (PPP_MP_CB(p)->BEbits & E) { 2813 struct sk_buff *tmp2; 2814 2815 skb_queue_reverse_walk_from_safe(list, p, tmp2) { 2816 if (ppp->debug & 1) 2817 netdev_printk(KERN_DEBUG, ppp->dev, 2818 "discarding frag %u\n", 2819 PPP_MP_CB(p)->sequence); 2820 __skb_unlink(p, list); 2821 kfree_skb(p); 2822 } 2823 head = skb_peek(list); 2824 if (!head) 2825 break; 2826 } 2827 ++seq; 2828 } 2829 2830 /* If we have a complete packet, copy it all into one skb. */ 2831 if (tail != NULL) { 2832 /* If we have discarded any fragments, 2833 signal a receive error. */ 2834 if (PPP_MP_CB(head)->sequence != ppp->nextseq) { 2835 skb_queue_walk_safe(list, p, tmp) { 2836 if (p == head) 2837 break; 2838 if (ppp->debug & 1) 2839 netdev_printk(KERN_DEBUG, ppp->dev, 2840 "discarding frag %u\n", 2841 PPP_MP_CB(p)->sequence); 2842 __skb_unlink(p, list); 2843 kfree_skb(p); 2844 } 2845 2846 if (ppp->debug & 1) 2847 netdev_printk(KERN_DEBUG, ppp->dev, 2848 " missed pkts %u..%u\n", 2849 ppp->nextseq, 2850 PPP_MP_CB(head)->sequence-1); 2851 ++ppp->dev->stats.rx_dropped; 2852 ppp_receive_error(ppp); 2853 } 2854 2855 skb = head; 2856 if (head != tail) { 2857 struct sk_buff **fragpp = &skb_shinfo(skb)->frag_list; 2858 p = skb_queue_next(list, head); 2859 __skb_unlink(skb, list); 2860 skb_queue_walk_from_safe(list, p, tmp) { 2861 __skb_unlink(p, list); 2862 *fragpp = p; 2863 p->next = NULL; 2864 fragpp = &p->next; 2865 2866 skb->len += p->len; 2867 skb->data_len += p->len; 2868 skb->truesize += p->truesize; 2869 2870 if (p == tail) 2871 break; 2872 } 2873 } else { 2874 __skb_unlink(skb, list); 2875 } 2876 2877 ppp->nextseq = PPP_MP_CB(tail)->sequence + 1; 2878 } 2879 2880 return skb; 2881 } 2882 #endif /* CONFIG_PPP_MULTILINK */ 2883 2884 /* 2885 * Channel interface. 2886 */ 2887 2888 /* Create a new, unattached ppp channel. */ 2889 int ppp_register_channel(struct ppp_channel *chan) 2890 { 2891 return ppp_register_net_channel(current->nsproxy->net_ns, chan); 2892 } 2893 2894 /* Create a new, unattached ppp channel for specified net. */ 2895 int ppp_register_net_channel(struct net *net, struct ppp_channel *chan) 2896 { 2897 struct channel *pch; 2898 struct ppp_net *pn; 2899 2900 pch = kzalloc(sizeof(struct channel), GFP_KERNEL); 2901 if (!pch) 2902 return -ENOMEM; 2903 2904 pn = ppp_pernet(net); 2905 2906 pch->ppp = NULL; 2907 pch->chan = chan; 2908 pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL); 2909 chan->ppp = pch; 2910 init_ppp_file(&pch->file, CHANNEL); 2911 pch->file.hdrlen = chan->hdrlen; 2912 #ifdef CONFIG_PPP_MULTILINK 2913 pch->lastseq = -1; 2914 #endif /* CONFIG_PPP_MULTILINK */ 2915 init_rwsem(&pch->chan_sem); 2916 spin_lock_init(&pch->downl); 2917 rwlock_init(&pch->upl); 2918 2919 spin_lock_bh(&pn->all_channels_lock); 2920 pch->file.index = ++pn->last_channel_index; 2921 list_add(&pch->list, &pn->new_channels); 2922 atomic_inc(&channel_count); 2923 spin_unlock_bh(&pn->all_channels_lock); 2924 2925 return 0; 2926 } 2927 2928 /* 2929 * Return the index of a channel. 2930 */ 2931 int ppp_channel_index(struct ppp_channel *chan) 2932 { 2933 struct channel *pch = chan->ppp; 2934 2935 if (pch) 2936 return pch->file.index; 2937 return -1; 2938 } 2939 2940 /* 2941 * Return the PPP unit number to which a channel is connected. 2942 */ 2943 int ppp_unit_number(struct ppp_channel *chan) 2944 { 2945 struct channel *pch = chan->ppp; 2946 int unit = -1; 2947 2948 if (pch) { 2949 read_lock_bh(&pch->upl); 2950 if (pch->ppp) 2951 unit = pch->ppp->file.index; 2952 read_unlock_bh(&pch->upl); 2953 } 2954 return unit; 2955 } 2956 2957 /* 2958 * Return the PPP device interface name of a channel. 2959 */ 2960 char *ppp_dev_name(struct ppp_channel *chan) 2961 { 2962 struct channel *pch = chan->ppp; 2963 char *name = NULL; 2964 2965 if (pch) { 2966 read_lock_bh(&pch->upl); 2967 if (pch->ppp && pch->ppp->dev) 2968 name = pch->ppp->dev->name; 2969 read_unlock_bh(&pch->upl); 2970 } 2971 return name; 2972 } 2973 2974 2975 /* 2976 * Disconnect a channel from the generic layer. 2977 * This must be called in process context. 2978 */ 2979 void 2980 ppp_unregister_channel(struct ppp_channel *chan) 2981 { 2982 struct channel *pch = chan->ppp; 2983 struct ppp_net *pn; 2984 2985 if (!pch) 2986 return; /* should never happen */ 2987 2988 chan->ppp = NULL; 2989 2990 /* 2991 * This ensures that we have returned from any calls into 2992 * the channel's start_xmit or ioctl routine before we proceed. 2993 */ 2994 down_write(&pch->chan_sem); 2995 spin_lock_bh(&pch->downl); 2996 pch->chan = NULL; 2997 spin_unlock_bh(&pch->downl); 2998 up_write(&pch->chan_sem); 2999 ppp_disconnect_channel(pch); 3000 3001 pn = ppp_pernet(pch->chan_net); 3002 spin_lock_bh(&pn->all_channels_lock); 3003 list_del(&pch->list); 3004 spin_unlock_bh(&pn->all_channels_lock); 3005 3006 ppp_unbridge_channels(pch); 3007 3008 pch->file.dead = 1; 3009 wake_up_interruptible(&pch->file.rwait); 3010 3011 if (refcount_dec_and_test(&pch->file.refcnt)) 3012 ppp_destroy_channel(pch); 3013 } 3014 3015 /* 3016 * Callback from a channel when it can accept more to transmit. 3017 * This should be called at BH/softirq level, not interrupt level. 3018 */ 3019 void 3020 ppp_output_wakeup(struct ppp_channel *chan) 3021 { 3022 struct channel *pch = chan->ppp; 3023 3024 if (!pch) 3025 return; 3026 ppp_channel_push(pch); 3027 } 3028 3029 /* 3030 * Compression control. 3031 */ 3032 3033 /* Process the PPPIOCSCOMPRESS ioctl. */ 3034 static int 3035 ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data) 3036 { 3037 int err = -EFAULT; 3038 struct compressor *cp, *ocomp; 3039 void *state, *ostate; 3040 unsigned char ccp_option[CCP_MAX_OPTION_LENGTH]; 3041 3042 if (data->length > CCP_MAX_OPTION_LENGTH) 3043 goto out; 3044 if (copy_from_user(ccp_option, data->ptr, data->length)) 3045 goto out; 3046 3047 err = -EINVAL; 3048 if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length) 3049 goto out; 3050 3051 cp = try_then_request_module( 3052 find_compressor(ccp_option[0]), 3053 "ppp-compress-%d", ccp_option[0]); 3054 if (!cp) 3055 goto out; 3056 3057 err = -ENOBUFS; 3058 if (data->transmit) { 3059 state = cp->comp_alloc(ccp_option, data->length); 3060 if (state) { 3061 ppp_xmit_lock(ppp); 3062 ppp->xstate &= ~SC_COMP_RUN; 3063 ocomp = ppp->xcomp; 3064 ostate = ppp->xc_state; 3065 ppp->xcomp = cp; 3066 ppp->xc_state = state; 3067 ppp_xmit_unlock(ppp); 3068 if (ostate) { 3069 ocomp->comp_free(ostate); 3070 module_put(ocomp->owner); 3071 } 3072 err = 0; 3073 } else 3074 module_put(cp->owner); 3075 3076 } else { 3077 state = cp->decomp_alloc(ccp_option, data->length); 3078 if (state) { 3079 ppp_recv_lock(ppp); 3080 ppp->rstate &= ~SC_DECOMP_RUN; 3081 ocomp = ppp->rcomp; 3082 ostate = ppp->rc_state; 3083 ppp->rcomp = cp; 3084 ppp->rc_state = state; 3085 ppp_recv_unlock(ppp); 3086 if (ostate) { 3087 ocomp->decomp_free(ostate); 3088 module_put(ocomp->owner); 3089 } 3090 err = 0; 3091 } else 3092 module_put(cp->owner); 3093 } 3094 3095 out: 3096 return err; 3097 } 3098 3099 /* 3100 * Look at a CCP packet and update our state accordingly. 3101 * We assume the caller has the xmit or recv path locked. 3102 */ 3103 static void 3104 ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound) 3105 { 3106 unsigned char *dp; 3107 int len; 3108 3109 if (!pskb_may_pull(skb, CCP_HDRLEN + 2)) 3110 return; /* no header */ 3111 dp = skb->data + 2; 3112 3113 switch (CCP_CODE(dp)) { 3114 case CCP_CONFREQ: 3115 3116 /* A ConfReq starts negotiation of compression 3117 * in one direction of transmission, 3118 * and hence brings it down...but which way? 3119 * 3120 * Remember: 3121 * A ConfReq indicates what the sender would like to receive 3122 */ 3123 if(inbound) 3124 /* He is proposing what I should send */ 3125 ppp->xstate &= ~SC_COMP_RUN; 3126 else 3127 /* I am proposing to what he should send */ 3128 ppp->rstate &= ~SC_DECOMP_RUN; 3129 3130 break; 3131 3132 case CCP_TERMREQ: 3133 case CCP_TERMACK: 3134 /* 3135 * CCP is going down, both directions of transmission 3136 */ 3137 ppp->rstate &= ~SC_DECOMP_RUN; 3138 ppp->xstate &= ~SC_COMP_RUN; 3139 break; 3140 3141 case CCP_CONFACK: 3142 if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN) 3143 break; 3144 len = CCP_LENGTH(dp); 3145 if (!pskb_may_pull(skb, len + 2)) 3146 return; /* too short */ 3147 dp += CCP_HDRLEN; 3148 len -= CCP_HDRLEN; 3149 if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp)) 3150 break; 3151 if (inbound) { 3152 /* we will start receiving compressed packets */ 3153 if (!ppp->rc_state) 3154 break; 3155 if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len, 3156 ppp->file.index, 0, ppp->mru, ppp->debug)) { 3157 ppp->rstate |= SC_DECOMP_RUN; 3158 ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR); 3159 } 3160 } else { 3161 /* we will soon start sending compressed packets */ 3162 if (!ppp->xc_state) 3163 break; 3164 if (ppp->xcomp->comp_init(ppp->xc_state, dp, len, 3165 ppp->file.index, 0, ppp->debug)) 3166 ppp->xstate |= SC_COMP_RUN; 3167 } 3168 break; 3169 3170 case CCP_RESETACK: 3171 /* reset the [de]compressor */ 3172 if ((ppp->flags & SC_CCP_UP) == 0) 3173 break; 3174 if (inbound) { 3175 if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) { 3176 ppp->rcomp->decomp_reset(ppp->rc_state); 3177 ppp->rstate &= ~SC_DC_ERROR; 3178 } 3179 } else { 3180 if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN)) 3181 ppp->xcomp->comp_reset(ppp->xc_state); 3182 } 3183 break; 3184 } 3185 } 3186 3187 /* Free up compression resources. */ 3188 static void 3189 ppp_ccp_closed(struct ppp *ppp) 3190 { 3191 void *xstate, *rstate; 3192 struct compressor *xcomp, *rcomp; 3193 3194 ppp_lock(ppp); 3195 ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP); 3196 ppp->xstate = 0; 3197 xcomp = ppp->xcomp; 3198 xstate = ppp->xc_state; 3199 ppp->xc_state = NULL; 3200 ppp->rstate = 0; 3201 rcomp = ppp->rcomp; 3202 rstate = ppp->rc_state; 3203 ppp->rc_state = NULL; 3204 ppp_unlock(ppp); 3205 3206 if (xstate) { 3207 xcomp->comp_free(xstate); 3208 module_put(xcomp->owner); 3209 } 3210 if (rstate) { 3211 rcomp->decomp_free(rstate); 3212 module_put(rcomp->owner); 3213 } 3214 } 3215 3216 /* List of compressors. */ 3217 static LIST_HEAD(compressor_list); 3218 static DEFINE_SPINLOCK(compressor_list_lock); 3219 3220 struct compressor_entry { 3221 struct list_head list; 3222 struct compressor *comp; 3223 }; 3224 3225 static struct compressor_entry * 3226 find_comp_entry(int proto) 3227 { 3228 struct compressor_entry *ce; 3229 3230 list_for_each_entry(ce, &compressor_list, list) { 3231 if (ce->comp->compress_proto == proto) 3232 return ce; 3233 } 3234 return NULL; 3235 } 3236 3237 /* Register a compressor */ 3238 int 3239 ppp_register_compressor(struct compressor *cp) 3240 { 3241 struct compressor_entry *ce; 3242 int ret; 3243 spin_lock(&compressor_list_lock); 3244 ret = -EEXIST; 3245 if (find_comp_entry(cp->compress_proto)) 3246 goto out; 3247 ret = -ENOMEM; 3248 ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC); 3249 if (!ce) 3250 goto out; 3251 ret = 0; 3252 ce->comp = cp; 3253 list_add(&ce->list, &compressor_list); 3254 out: 3255 spin_unlock(&compressor_list_lock); 3256 return ret; 3257 } 3258 3259 /* Unregister a compressor */ 3260 void 3261 ppp_unregister_compressor(struct compressor *cp) 3262 { 3263 struct compressor_entry *ce; 3264 3265 spin_lock(&compressor_list_lock); 3266 ce = find_comp_entry(cp->compress_proto); 3267 if (ce && ce->comp == cp) { 3268 list_del(&ce->list); 3269 kfree(ce); 3270 } 3271 spin_unlock(&compressor_list_lock); 3272 } 3273 3274 /* Find a compressor. */ 3275 static struct compressor * 3276 find_compressor(int type) 3277 { 3278 struct compressor_entry *ce; 3279 struct compressor *cp = NULL; 3280 3281 spin_lock(&compressor_list_lock); 3282 ce = find_comp_entry(type); 3283 if (ce) { 3284 cp = ce->comp; 3285 if (!try_module_get(cp->owner)) 3286 cp = NULL; 3287 } 3288 spin_unlock(&compressor_list_lock); 3289 return cp; 3290 } 3291 3292 /* 3293 * Miscelleneous stuff. 3294 */ 3295 3296 static void 3297 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st) 3298 { 3299 struct slcompress *vj = ppp->vj; 3300 3301 memset(st, 0, sizeof(*st)); 3302 st->p.ppp_ipackets = ppp->stats64.rx_packets; 3303 st->p.ppp_ierrors = ppp->dev->stats.rx_errors; 3304 st->p.ppp_ibytes = ppp->stats64.rx_bytes; 3305 st->p.ppp_opackets = ppp->stats64.tx_packets; 3306 st->p.ppp_oerrors = ppp->dev->stats.tx_errors; 3307 st->p.ppp_obytes = ppp->stats64.tx_bytes; 3308 if (!vj) 3309 return; 3310 st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed; 3311 st->vj.vjs_compressed = vj->sls_o_compressed; 3312 st->vj.vjs_searches = vj->sls_o_searches; 3313 st->vj.vjs_misses = vj->sls_o_misses; 3314 st->vj.vjs_errorin = vj->sls_i_error; 3315 st->vj.vjs_tossed = vj->sls_i_tossed; 3316 st->vj.vjs_uncompressedin = vj->sls_i_uncompressed; 3317 st->vj.vjs_compressedin = vj->sls_i_compressed; 3318 } 3319 3320 /* 3321 * Stuff for handling the lists of ppp units and channels 3322 * and for initialization. 3323 */ 3324 3325 /* 3326 * Create a new ppp interface unit. Fails if it can't allocate memory 3327 * or if there is already a unit with the requested number. 3328 * unit == -1 means allocate a new number. 3329 */ 3330 static int ppp_create_interface(struct net *net, struct file *file, int *unit) 3331 { 3332 struct ppp_config conf = { 3333 .file = file, 3334 .unit = *unit, 3335 .ifname_is_set = false, 3336 }; 3337 struct net_device *dev; 3338 struct ppp *ppp; 3339 int err; 3340 3341 dev = alloc_netdev(sizeof(struct ppp), "", NET_NAME_ENUM, ppp_setup); 3342 if (!dev) { 3343 err = -ENOMEM; 3344 goto err; 3345 } 3346 dev_net_set(dev, net); 3347 dev->rtnl_link_ops = &ppp_link_ops; 3348 3349 rtnl_lock(); 3350 3351 err = ppp_dev_configure(net, dev, &conf); 3352 if (err < 0) 3353 goto err_dev; 3354 ppp = netdev_priv(dev); 3355 *unit = ppp->file.index; 3356 3357 rtnl_unlock(); 3358 3359 return 0; 3360 3361 err_dev: 3362 rtnl_unlock(); 3363 free_netdev(dev); 3364 err: 3365 return err; 3366 } 3367 3368 /* 3369 * Initialize a ppp_file structure. 3370 */ 3371 static void 3372 init_ppp_file(struct ppp_file *pf, int kind) 3373 { 3374 pf->kind = kind; 3375 skb_queue_head_init(&pf->xq); 3376 skb_queue_head_init(&pf->rq); 3377 refcount_set(&pf->refcnt, 1); 3378 init_waitqueue_head(&pf->rwait); 3379 } 3380 3381 /* 3382 * Free the memory used by a ppp unit. This is only called once 3383 * there are no channels connected to the unit and no file structs 3384 * that reference the unit. 3385 */ 3386 static void ppp_destroy_interface(struct ppp *ppp) 3387 { 3388 atomic_dec(&ppp_unit_count); 3389 3390 if (!ppp->file.dead || ppp->n_channels) { 3391 /* "can't happen" */ 3392 netdev_err(ppp->dev, "ppp: destroying ppp struct %p " 3393 "but dead=%d n_channels=%d !\n", 3394 ppp, ppp->file.dead, ppp->n_channels); 3395 return; 3396 } 3397 3398 ppp_ccp_closed(ppp); 3399 if (ppp->vj) { 3400 slhc_free(ppp->vj); 3401 ppp->vj = NULL; 3402 } 3403 skb_queue_purge(&ppp->file.xq); 3404 skb_queue_purge(&ppp->file.rq); 3405 #ifdef CONFIG_PPP_MULTILINK 3406 skb_queue_purge(&ppp->mrq); 3407 #endif /* CONFIG_PPP_MULTILINK */ 3408 #ifdef CONFIG_PPP_FILTER 3409 if (ppp->pass_filter) { 3410 bpf_prog_destroy(ppp->pass_filter); 3411 ppp->pass_filter = NULL; 3412 } 3413 3414 if (ppp->active_filter) { 3415 bpf_prog_destroy(ppp->active_filter); 3416 ppp->active_filter = NULL; 3417 } 3418 #endif /* CONFIG_PPP_FILTER */ 3419 3420 kfree_skb(ppp->xmit_pending); 3421 free_percpu(ppp->xmit_recursion); 3422 3423 free_netdev(ppp->dev); 3424 } 3425 3426 /* 3427 * Locate an existing ppp unit. 3428 * The caller should have locked the all_ppp_mutex. 3429 */ 3430 static struct ppp * 3431 ppp_find_unit(struct ppp_net *pn, int unit) 3432 { 3433 return unit_find(&pn->units_idr, unit); 3434 } 3435 3436 /* 3437 * Locate an existing ppp channel. 3438 * The caller should have locked the all_channels_lock. 3439 * First we look in the new_channels list, then in the 3440 * all_channels list. If found in the new_channels list, 3441 * we move it to the all_channels list. This is for speed 3442 * when we have a lot of channels in use. 3443 */ 3444 static struct channel * 3445 ppp_find_channel(struct ppp_net *pn, int unit) 3446 { 3447 struct channel *pch; 3448 3449 list_for_each_entry(pch, &pn->new_channels, list) { 3450 if (pch->file.index == unit) { 3451 list_move(&pch->list, &pn->all_channels); 3452 return pch; 3453 } 3454 } 3455 3456 list_for_each_entry(pch, &pn->all_channels, list) { 3457 if (pch->file.index == unit) 3458 return pch; 3459 } 3460 3461 return NULL; 3462 } 3463 3464 /* 3465 * Connect a PPP channel to a PPP interface unit. 3466 */ 3467 static int 3468 ppp_connect_channel(struct channel *pch, int unit) 3469 { 3470 struct ppp *ppp; 3471 struct ppp_net *pn; 3472 int ret = -ENXIO; 3473 int hdrlen; 3474 3475 pn = ppp_pernet(pch->chan_net); 3476 3477 mutex_lock(&pn->all_ppp_mutex); 3478 ppp = ppp_find_unit(pn, unit); 3479 if (!ppp) 3480 goto out; 3481 write_lock_bh(&pch->upl); 3482 ret = -EINVAL; 3483 if (pch->ppp || 3484 rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) 3485 goto outl; 3486 3487 ppp_lock(ppp); 3488 spin_lock_bh(&pch->downl); 3489 if (!pch->chan) { 3490 /* Don't connect unregistered channels */ 3491 spin_unlock_bh(&pch->downl); 3492 ppp_unlock(ppp); 3493 ret = -ENOTCONN; 3494 goto outl; 3495 } 3496 if (pch->chan->direct_xmit) 3497 ppp->dev->priv_flags |= IFF_NO_QUEUE; 3498 else 3499 ppp->dev->priv_flags &= ~IFF_NO_QUEUE; 3500 spin_unlock_bh(&pch->downl); 3501 if (pch->file.hdrlen > ppp->file.hdrlen) 3502 ppp->file.hdrlen = pch->file.hdrlen; 3503 hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */ 3504 if (hdrlen > ppp->dev->hard_header_len) 3505 ppp->dev->hard_header_len = hdrlen; 3506 list_add_tail(&pch->clist, &ppp->channels); 3507 ++ppp->n_channels; 3508 pch->ppp = ppp; 3509 refcount_inc(&ppp->file.refcnt); 3510 ppp_unlock(ppp); 3511 ret = 0; 3512 3513 outl: 3514 write_unlock_bh(&pch->upl); 3515 out: 3516 mutex_unlock(&pn->all_ppp_mutex); 3517 return ret; 3518 } 3519 3520 /* 3521 * Disconnect a channel from its ppp unit. 3522 */ 3523 static int 3524 ppp_disconnect_channel(struct channel *pch) 3525 { 3526 struct ppp *ppp; 3527 int err = -EINVAL; 3528 3529 write_lock_bh(&pch->upl); 3530 ppp = pch->ppp; 3531 pch->ppp = NULL; 3532 write_unlock_bh(&pch->upl); 3533 if (ppp) { 3534 /* remove it from the ppp unit's list */ 3535 ppp_lock(ppp); 3536 list_del(&pch->clist); 3537 if (--ppp->n_channels == 0) 3538 wake_up_interruptible(&ppp->file.rwait); 3539 ppp_unlock(ppp); 3540 if (refcount_dec_and_test(&ppp->file.refcnt)) 3541 ppp_destroy_interface(ppp); 3542 err = 0; 3543 } 3544 return err; 3545 } 3546 3547 /* 3548 * Free up the resources used by a ppp channel. 3549 */ 3550 static void ppp_destroy_channel(struct channel *pch) 3551 { 3552 put_net_track(pch->chan_net, &pch->ns_tracker); 3553 pch->chan_net = NULL; 3554 3555 atomic_dec(&channel_count); 3556 3557 if (!pch->file.dead) { 3558 /* "can't happen" */ 3559 pr_err("ppp: destroying undead channel %p !\n", pch); 3560 return; 3561 } 3562 skb_queue_purge(&pch->file.xq); 3563 skb_queue_purge(&pch->file.rq); 3564 kfree(pch); 3565 } 3566 3567 static void __exit ppp_cleanup(void) 3568 { 3569 /* should never happen */ 3570 if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count)) 3571 pr_err("PPP: removing module but units remain!\n"); 3572 rtnl_link_unregister(&ppp_link_ops); 3573 unregister_chrdev(PPP_MAJOR, "ppp"); 3574 device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0)); 3575 class_unregister(&ppp_class); 3576 unregister_pernet_device(&ppp_net_ops); 3577 } 3578 3579 /* 3580 * Units handling. Caller must protect concurrent access 3581 * by holding all_ppp_mutex 3582 */ 3583 3584 /* associate pointer with specified number */ 3585 static int unit_set(struct idr *p, void *ptr, int n) 3586 { 3587 int unit; 3588 3589 unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL); 3590 if (unit == -ENOSPC) 3591 unit = -EINVAL; 3592 return unit; 3593 } 3594 3595 /* get new free unit number and associate pointer with it */ 3596 static int unit_get(struct idr *p, void *ptr, int min) 3597 { 3598 return idr_alloc(p, ptr, min, 0, GFP_KERNEL); 3599 } 3600 3601 /* put unit number back to a pool */ 3602 static void unit_put(struct idr *p, int n) 3603 { 3604 idr_remove(p, n); 3605 } 3606 3607 /* get pointer associated with the number */ 3608 static void *unit_find(struct idr *p, int n) 3609 { 3610 return idr_find(p, n); 3611 } 3612 3613 /* Module/initialization stuff */ 3614 3615 module_init(ppp_init); 3616 module_exit(ppp_cleanup); 3617 3618 EXPORT_SYMBOL(ppp_register_net_channel); 3619 EXPORT_SYMBOL(ppp_register_channel); 3620 EXPORT_SYMBOL(ppp_unregister_channel); 3621 EXPORT_SYMBOL(ppp_channel_index); 3622 EXPORT_SYMBOL(ppp_unit_number); 3623 EXPORT_SYMBOL(ppp_dev_name); 3624 EXPORT_SYMBOL(ppp_input); 3625 EXPORT_SYMBOL(ppp_input_error); 3626 EXPORT_SYMBOL(ppp_output_wakeup); 3627 EXPORT_SYMBOL(ppp_register_compressor); 3628 EXPORT_SYMBOL(ppp_unregister_compressor); 3629 MODULE_DESCRIPTION("Generic PPP layer driver"); 3630 MODULE_LICENSE("GPL"); 3631 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0); 3632 MODULE_ALIAS_RTNL_LINK("ppp"); 3633 MODULE_ALIAS("devname:ppp"); 3634