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v6.8
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/** -*- linux-c -*- ***********************************************************
   3 * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
   4 *
   5 * PPPoX --- Generic PPP encapsulation socket family
   6 * PPPoE --- PPP over Ethernet (RFC 2516)
   7 *
   8 * Version:	0.7.0
   9 *
  10 * 070228 :	Fix to allow multiple sessions with same remote MAC and same
  11 *		session id by including the local device ifindex in the
  12 *		tuple identifying a session. This also ensures packets can't
  13 *		be injected into a session from interfaces other than the one
  14 *		specified by userspace. Florian Zumbiehl <florz@florz.de>
  15 *		(Oh, BTW, this one is YYMMDD, in case you were wondering ...)
  16 * 220102 :	Fix module use count on failure in pppoe_create, pppox_sk -acme
  17 * 030700 :	Fixed connect logic to allow for disconnect.
  18 * 270700 :	Fixed potential SMP problems; we must protect against
  19 *		simultaneous invocation of ppp_input
  20 *		and ppp_unregister_channel.
  21 * 040800 :	Respect reference count mechanisms on net-devices.
  22 * 200800 :	fix kfree(skb) in pppoe_rcv (acme)
  23 *		Module reference count is decremented in the right spot now,
  24 *		guards against sock_put not actually freeing the sk
  25 *		in pppoe_release.
  26 * 051000 :	Initialization cleanup.
  27 * 111100 :	Fix recvmsg.
  28 * 050101 :	Fix PADT processing.
  29 * 140501 :	Use pppoe_rcv_core to handle all backlog. (Alexey)
  30 * 170701 :	Do not lock_sock with rwlock held. (DaveM)
  31 *		Ignore discovery frames if user has socket
  32 *		locked. (DaveM)
  33 *		Ignore return value of dev_queue_xmit in __pppoe_xmit
  34 *		or else we may kfree an SKB twice. (DaveM)
  35 * 190701 :	When doing copies of skb's in __pppoe_xmit, always delete
  36 *		the original skb that was passed in on success, never on
  37 *		failure.  Delete the copy of the skb on failure to avoid
  38 *		a memory leak.
  39 * 081001 :	Misc. cleanup (licence string, non-blocking, prevent
  40 *		reference of device on close).
  41 * 121301 :	New ppp channels interface; cannot unregister a channel
  42 *		from interrupts.  Thus, we mark the socket as a ZOMBIE
  43 *		and do the unregistration later.
  44 * 081002 :	seq_file support for proc stuff -acme
  45 * 111602 :	Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
  46 *		as version 0.7.  Spacing cleanup.
  47 * Author:	Michal Ostrowski <mostrows@speakeasy.net>
  48 * Contributors:
  49 * 		Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  50 *		David S. Miller (davem@redhat.com)
  51 *
  52 * License:
  53 */
  54
  55#include <linux/string.h>
  56#include <linux/module.h>
  57#include <linux/kernel.h>
  58#include <linux/slab.h>
  59#include <linux/errno.h>
  60#include <linux/netdevice.h>
  61#include <linux/net.h>
  62#include <linux/inetdevice.h>
  63#include <linux/etherdevice.h>
  64#include <linux/skbuff.h>
  65#include <linux/init.h>
  66#include <linux/if_ether.h>
  67#include <linux/if_pppox.h>
  68#include <linux/ppp_channel.h>
  69#include <linux/ppp_defs.h>
  70#include <linux/ppp-ioctl.h>
  71#include <linux/notifier.h>
  72#include <linux/file.h>
  73#include <linux/proc_fs.h>
  74#include <linux/seq_file.h>
  75
  76#include <linux/nsproxy.h>
  77#include <net/net_namespace.h>
  78#include <net/netns/generic.h>
  79#include <net/sock.h>
  80
  81#include <linux/uaccess.h>
  82
  83#define PPPOE_HASH_BITS CONFIG_PPPOE_HASH_BITS
  84#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
  85#define PPPOE_HASH_MASK	(PPPOE_HASH_SIZE - 1)
  86
  87static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
  88
  89static const struct proto_ops pppoe_ops;
  90static const struct ppp_channel_ops pppoe_chan_ops;
  91
  92/* per-net private data for this module */
  93static unsigned int pppoe_net_id __read_mostly;
  94struct pppoe_net {
  95	/*
  96	 * we could use _single_ hash table for all
  97	 * nets by injecting net id into the hash but
  98	 * it would increase hash chains and add
  99	 * a few additional math comparisons messy
 100	 * as well, moreover in case of SMP less locking
 101	 * controversy here
 102	 */
 103	struct pppox_sock *hash_table[PPPOE_HASH_SIZE];
 104	rwlock_t hash_lock;
 105};
 106
 107/*
 108 * PPPoE could be in the following stages:
 109 * 1) Discovery stage (to obtain remote MAC and Session ID)
 110 * 2) Session stage (MAC and SID are known)
 111 *
 112 * Ethernet frames have a special tag for this but
 113 * we use simpler approach based on session id
 114 */
 115static inline bool stage_session(__be16 sid)
 116{
 117	return sid != 0;
 118}
 119
 120static inline struct pppoe_net *pppoe_pernet(struct net *net)
 121{
 
 
 122	return net_generic(net, pppoe_net_id);
 123}
 124
 125static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
 126{
 127	return a->sid == b->sid && ether_addr_equal(a->remote, b->remote);
 128}
 129
 130static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
 131{
 132	return a->sid == sid && ether_addr_equal(a->remote, addr);
 133}
 134
 135#if 8 % PPPOE_HASH_BITS
 136#error 8 must be a multiple of PPPOE_HASH_BITS
 137#endif
 138
 139static int hash_item(__be16 sid, unsigned char *addr)
 140{
 141	unsigned char hash = 0;
 142	unsigned int i;
 143
 144	for (i = 0; i < ETH_ALEN; i++)
 145		hash ^= addr[i];
 146	for (i = 0; i < sizeof(sid_t) * 8; i += 8)
 147		hash ^= (__force __u32)sid >> i;
 148	for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
 149		hash ^= hash >> i;
 150
 151	return hash & PPPOE_HASH_MASK;
 152}
 153
 154/**********************************************************************
 155 *
 156 *  Set/get/delete/rehash items  (internal versions)
 157 *
 158 **********************************************************************/
 159static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
 160				unsigned char *addr, int ifindex)
 161{
 162	int hash = hash_item(sid, addr);
 163	struct pppox_sock *ret;
 164
 165	ret = pn->hash_table[hash];
 166	while (ret) {
 167		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 168		    ret->pppoe_ifindex == ifindex)
 169			return ret;
 170
 171		ret = ret->next;
 172	}
 173
 174	return NULL;
 175}
 176
 177static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
 178{
 179	int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
 180	struct pppox_sock *ret;
 181
 182	ret = pn->hash_table[hash];
 183	while (ret) {
 184		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
 185		    ret->pppoe_ifindex == po->pppoe_ifindex)
 186			return -EALREADY;
 187
 188		ret = ret->next;
 189	}
 190
 191	po->next = pn->hash_table[hash];
 192	pn->hash_table[hash] = po;
 193
 194	return 0;
 195}
 196
 197static void __delete_item(struct pppoe_net *pn, __be16 sid,
 198					char *addr, int ifindex)
 199{
 200	int hash = hash_item(sid, addr);
 201	struct pppox_sock *ret, **src;
 202
 203	ret = pn->hash_table[hash];
 204	src = &pn->hash_table[hash];
 205
 206	while (ret) {
 207		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 208		    ret->pppoe_ifindex == ifindex) {
 209			*src = ret->next;
 210			break;
 211		}
 212
 213		src = &ret->next;
 214		ret = ret->next;
 215	}
 216}
 217
 218/**********************************************************************
 219 *
 220 *  Set/get/delete/rehash items
 221 *
 222 **********************************************************************/
 223static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
 224					unsigned char *addr, int ifindex)
 225{
 226	struct pppox_sock *po;
 227
 228	read_lock_bh(&pn->hash_lock);
 229	po = __get_item(pn, sid, addr, ifindex);
 230	if (po)
 231		sock_hold(sk_pppox(po));
 232	read_unlock_bh(&pn->hash_lock);
 233
 234	return po;
 235}
 236
 237static inline struct pppox_sock *get_item_by_addr(struct net *net,
 238						struct sockaddr_pppox *sp)
 239{
 240	struct net_device *dev;
 241	struct pppoe_net *pn;
 242	struct pppox_sock *pppox_sock = NULL;
 243
 244	int ifindex;
 245
 246	rcu_read_lock();
 247	dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
 248	if (dev) {
 249		ifindex = dev->ifindex;
 250		pn = pppoe_pernet(net);
 251		pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
 252				sp->sa_addr.pppoe.remote, ifindex);
 253	}
 254	rcu_read_unlock();
 255	return pppox_sock;
 256}
 257
 258static inline void delete_item(struct pppoe_net *pn, __be16 sid,
 259					char *addr, int ifindex)
 260{
 261	write_lock_bh(&pn->hash_lock);
 262	__delete_item(pn, sid, addr, ifindex);
 263	write_unlock_bh(&pn->hash_lock);
 264}
 265
 266/***************************************************************************
 267 *
 268 *  Handler for device events.
 269 *  Certain device events require that sockets be unconnected.
 270 *
 271 **************************************************************************/
 272
 273static void pppoe_flush_dev(struct net_device *dev)
 274{
 275	struct pppoe_net *pn;
 276	int i;
 277
 278	pn = pppoe_pernet(dev_net(dev));
 279	write_lock_bh(&pn->hash_lock);
 280	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 281		struct pppox_sock *po = pn->hash_table[i];
 282		struct sock *sk;
 283
 284		while (po) {
 285			while (po && po->pppoe_dev != dev) {
 286				po = po->next;
 287			}
 288
 289			if (!po)
 290				break;
 291
 292			sk = sk_pppox(po);
 293
 294			/* We always grab the socket lock, followed by the
 295			 * hash_lock, in that order.  Since we should hold the
 296			 * sock lock while doing any unbinding, we need to
 297			 * release the lock we're holding.  Hold a reference to
 298			 * the sock so it doesn't disappear as we're jumping
 299			 * between locks.
 300			 */
 301
 302			sock_hold(sk);
 303			write_unlock_bh(&pn->hash_lock);
 304			lock_sock(sk);
 305
 306			if (po->pppoe_dev == dev &&
 307			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
 308				pppox_unbind_sock(sk);
 309				sk->sk_state_change(sk);
 310				po->pppoe_dev = NULL;
 311				dev_put(dev);
 312			}
 313
 314			release_sock(sk);
 315			sock_put(sk);
 316
 317			/* Restart the process from the start of the current
 318			 * hash chain. We dropped locks so the world may have
 319			 * change from underneath us.
 320			 */
 321
 322			BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
 323			write_lock_bh(&pn->hash_lock);
 324			po = pn->hash_table[i];
 325		}
 326	}
 327	write_unlock_bh(&pn->hash_lock);
 328}
 329
 330static int pppoe_device_event(struct notifier_block *this,
 331			      unsigned long event, void *ptr)
 332{
 333	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 334
 335	/* Only look at sockets that are using this specific device. */
 336	switch (event) {
 337	case NETDEV_CHANGEADDR:
 338	case NETDEV_CHANGEMTU:
 339		/* A change in mtu or address is a bad thing, requiring
 340		 * LCP re-negotiation.
 341		 */
 342
 343	case NETDEV_GOING_DOWN:
 344	case NETDEV_DOWN:
 345		/* Find every socket on this device and kill it. */
 346		pppoe_flush_dev(dev);
 347		break;
 348
 349	default:
 350		break;
 351	}
 352
 353	return NOTIFY_DONE;
 354}
 355
 356static struct notifier_block pppoe_notifier = {
 357	.notifier_call = pppoe_device_event,
 358};
 359
 360/************************************************************************
 361 *
 362 * Do the real work of receiving a PPPoE Session frame.
 363 *
 364 ***********************************************************************/
 365static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
 366{
 367	struct pppox_sock *po = pppox_sk(sk);
 368	struct pppox_sock *relay_po;
 369
 370	/* Backlog receive. Semantics of backlog rcv preclude any code from
 371	 * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
 372	 * can't change.
 373	 */
 374
 375	if (skb->pkt_type == PACKET_OTHERHOST)
 376		goto abort_kfree;
 377
 378	if (sk->sk_state & PPPOX_BOUND) {
 379		ppp_input(&po->chan, skb);
 380	} else if (sk->sk_state & PPPOX_RELAY) {
 381		relay_po = get_item_by_addr(sock_net(sk),
 382					    &po->pppoe_relay);
 383		if (relay_po == NULL)
 384			goto abort_kfree;
 385
 386		if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
 387			goto abort_put;
 388
 389		if (!__pppoe_xmit(sk_pppox(relay_po), skb))
 390			goto abort_put;
 391
 392		sock_put(sk_pppox(relay_po));
 393	} else {
 394		if (sock_queue_rcv_skb(sk, skb))
 395			goto abort_kfree;
 396	}
 397
 398	return NET_RX_SUCCESS;
 399
 400abort_put:
 401	sock_put(sk_pppox(relay_po));
 402
 403abort_kfree:
 404	kfree_skb(skb);
 405	return NET_RX_DROP;
 406}
 407
 408/************************************************************************
 409 *
 410 * Receive wrapper called in BH context.
 411 *
 412 ***********************************************************************/
 413static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
 414		     struct packet_type *pt, struct net_device *orig_dev)
 415{
 416	struct pppoe_hdr *ph;
 417	struct pppox_sock *po;
 418	struct pppoe_net *pn;
 419	int len;
 420
 421	skb = skb_share_check(skb, GFP_ATOMIC);
 422	if (!skb)
 423		goto out;
 424
 425	if (skb_mac_header_len(skb) < ETH_HLEN)
 426		goto drop;
 427
 428	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 429		goto drop;
 430
 431	ph = pppoe_hdr(skb);
 432	len = ntohs(ph->length);
 433
 434	skb_pull_rcsum(skb, sizeof(*ph));
 435	if (skb->len < len)
 436		goto drop;
 437
 438	if (pskb_trim_rcsum(skb, len))
 439		goto drop;
 440
 441	ph = pppoe_hdr(skb);
 442	pn = pppoe_pernet(dev_net(dev));
 443
 444	/* Note that get_item does a sock_hold(), so sk_pppox(po)
 445	 * is known to be safe.
 446	 */
 447	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 448	if (!po)
 449		goto drop;
 450
 451	return sk_receive_skb(sk_pppox(po), skb, 0);
 452
 453drop:
 454	kfree_skb(skb);
 455out:
 456	return NET_RX_DROP;
 457}
 458
 459static void pppoe_unbind_sock_work(struct work_struct *work)
 460{
 461	struct pppox_sock *po = container_of(work, struct pppox_sock,
 462					     proto.pppoe.padt_work);
 463	struct sock *sk = sk_pppox(po);
 464
 465	lock_sock(sk);
 466	if (po->pppoe_dev) {
 467		dev_put(po->pppoe_dev);
 468		po->pppoe_dev = NULL;
 469	}
 470	pppox_unbind_sock(sk);
 471	release_sock(sk);
 472	sock_put(sk);
 473}
 474
 475/************************************************************************
 476 *
 477 * Receive a PPPoE Discovery frame.
 478 * This is solely for detection of PADT frames
 479 *
 480 ***********************************************************************/
 481static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
 482			  struct packet_type *pt, struct net_device *orig_dev)
 483
 484{
 485	struct pppoe_hdr *ph;
 486	struct pppox_sock *po;
 487	struct pppoe_net *pn;
 488
 489	skb = skb_share_check(skb, GFP_ATOMIC);
 490	if (!skb)
 491		goto out;
 492
 493	if (skb->pkt_type != PACKET_HOST)
 494		goto abort;
 495
 496	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 497		goto abort;
 498
 499	ph = pppoe_hdr(skb);
 500	if (ph->code != PADT_CODE)
 501		goto abort;
 502
 503	pn = pppoe_pernet(dev_net(dev));
 504	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 505	if (po)
 506		if (!schedule_work(&po->proto.pppoe.padt_work))
 507			sock_put(sk_pppox(po));
 508
 509abort:
 510	kfree_skb(skb);
 511out:
 512	return NET_RX_SUCCESS; /* Lies... :-) */
 513}
 514
 515static struct packet_type pppoes_ptype __read_mostly = {
 516	.type	= cpu_to_be16(ETH_P_PPP_SES),
 517	.func	= pppoe_rcv,
 518};
 519
 520static struct packet_type pppoed_ptype __read_mostly = {
 521	.type	= cpu_to_be16(ETH_P_PPP_DISC),
 522	.func	= pppoe_disc_rcv,
 523};
 524
 525static struct proto pppoe_sk_proto __read_mostly = {
 526	.name	  = "PPPOE",
 527	.owner	  = THIS_MODULE,
 528	.obj_size = sizeof(struct pppox_sock),
 529};
 530
 531/***********************************************************************
 532 *
 533 * Initialize a new struct sock.
 534 *
 535 **********************************************************************/
 536static int pppoe_create(struct net *net, struct socket *sock, int kern)
 537{
 538	struct sock *sk;
 539
 540	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, kern);
 541	if (!sk)
 542		return -ENOMEM;
 543
 544	sock_init_data(sock, sk);
 545
 546	sock->state	= SS_UNCONNECTED;
 547	sock->ops	= &pppoe_ops;
 548
 549	sk->sk_backlog_rcv	= pppoe_rcv_core;
 550	sk->sk_state		= PPPOX_NONE;
 551	sk->sk_type		= SOCK_STREAM;
 552	sk->sk_family		= PF_PPPOX;
 553	sk->sk_protocol		= PX_PROTO_OE;
 554
 555	INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
 556		  pppoe_unbind_sock_work);
 557
 558	return 0;
 559}
 560
 561static int pppoe_release(struct socket *sock)
 562{
 563	struct sock *sk = sock->sk;
 564	struct pppox_sock *po;
 565	struct pppoe_net *pn;
 566	struct net *net = NULL;
 567
 568	if (!sk)
 569		return 0;
 570
 571	lock_sock(sk);
 572	if (sock_flag(sk, SOCK_DEAD)) {
 573		release_sock(sk);
 574		return -EBADF;
 575	}
 576
 577	po = pppox_sk(sk);
 578
 579	if (po->pppoe_dev) {
 580		dev_put(po->pppoe_dev);
 581		po->pppoe_dev = NULL;
 582	}
 583
 584	pppox_unbind_sock(sk);
 585
 586	/* Signal the death of the socket. */
 587	sk->sk_state = PPPOX_DEAD;
 588
 589	net = sock_net(sk);
 590	pn = pppoe_pernet(net);
 591
 592	/*
 593	 * protect "po" from concurrent updates
 594	 * on pppoe_flush_dev
 595	 */
 596	delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
 597		    po->pppoe_ifindex);
 598
 599	sock_orphan(sk);
 600	sock->sk = NULL;
 601
 602	skb_queue_purge(&sk->sk_receive_queue);
 603	release_sock(sk);
 604	sock_put(sk);
 605
 606	return 0;
 607}
 608
 609static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
 610		  int sockaddr_len, int flags)
 611{
 612	struct sock *sk = sock->sk;
 613	struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
 614	struct pppox_sock *po = pppox_sk(sk);
 615	struct net_device *dev = NULL;
 616	struct pppoe_net *pn;
 617	struct net *net = NULL;
 618	int error;
 619
 620	lock_sock(sk);
 621
 622	error = -EINVAL;
 623
 624	if (sockaddr_len != sizeof(struct sockaddr_pppox))
 625		goto end;
 626
 627	if (sp->sa_protocol != PX_PROTO_OE)
 628		goto end;
 629
 630	/* Check for already bound sockets */
 631	error = -EBUSY;
 632	if ((sk->sk_state & PPPOX_CONNECTED) &&
 633	     stage_session(sp->sa_addr.pppoe.sid))
 634		goto end;
 635
 636	/* Check for already disconnected sockets, on attempts to disconnect */
 637	error = -EALREADY;
 638	if ((sk->sk_state & PPPOX_DEAD) &&
 639	     !stage_session(sp->sa_addr.pppoe.sid))
 640		goto end;
 641
 642	error = 0;
 643
 644	/* Delete the old binding */
 645	if (stage_session(po->pppoe_pa.sid)) {
 646		pppox_unbind_sock(sk);
 647		pn = pppoe_pernet(sock_net(sk));
 648		delete_item(pn, po->pppoe_pa.sid,
 649			    po->pppoe_pa.remote, po->pppoe_ifindex);
 650		if (po->pppoe_dev) {
 651			dev_put(po->pppoe_dev);
 652			po->pppoe_dev = NULL;
 653		}
 654
 655		po->pppoe_ifindex = 0;
 656		memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
 657		memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay));
 658		memset(&po->chan, 0, sizeof(po->chan));
 659		po->next = NULL;
 660		po->num = 0;
 661
 662		sk->sk_state = PPPOX_NONE;
 663	}
 664
 665	/* Re-bind in session stage only */
 666	if (stage_session(sp->sa_addr.pppoe.sid)) {
 667		error = -ENODEV;
 668		net = sock_net(sk);
 669		dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
 670		if (!dev)
 671			goto err_put;
 672
 673		po->pppoe_dev = dev;
 674		po->pppoe_ifindex = dev->ifindex;
 675		pn = pppoe_pernet(net);
 676		if (!(dev->flags & IFF_UP)) {
 677			goto err_put;
 678		}
 679
 680		memcpy(&po->pppoe_pa,
 681		       &sp->sa_addr.pppoe,
 682		       sizeof(struct pppoe_addr));
 683
 684		write_lock_bh(&pn->hash_lock);
 685		error = __set_item(pn, po);
 686		write_unlock_bh(&pn->hash_lock);
 687		if (error < 0)
 688			goto err_put;
 689
 690		po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
 691				   dev->hard_header_len);
 692
 693		po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
 694		po->chan.private = sk;
 695		po->chan.ops = &pppoe_chan_ops;
 696
 697		error = ppp_register_net_channel(dev_net(dev), &po->chan);
 698		if (error) {
 699			delete_item(pn, po->pppoe_pa.sid,
 700				    po->pppoe_pa.remote, po->pppoe_ifindex);
 701			goto err_put;
 702		}
 703
 704		sk->sk_state = PPPOX_CONNECTED;
 705	}
 706
 707	po->num = sp->sa_addr.pppoe.sid;
 708
 709end:
 710	release_sock(sk);
 711	return error;
 712err_put:
 713	if (po->pppoe_dev) {
 714		dev_put(po->pppoe_dev);
 715		po->pppoe_dev = NULL;
 716	}
 717	goto end;
 718}
 719
 720static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
 721		  int peer)
 722{
 723	int len = sizeof(struct sockaddr_pppox);
 724	struct sockaddr_pppox sp;
 725
 726	sp.sa_family	= AF_PPPOX;
 727	sp.sa_protocol	= PX_PROTO_OE;
 728	memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
 729	       sizeof(struct pppoe_addr));
 730
 731	memcpy(uaddr, &sp, len);
 732
 733	return len;
 734}
 735
 736static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
 737		unsigned long arg)
 738{
 739	struct sock *sk = sock->sk;
 740	struct pppox_sock *po = pppox_sk(sk);
 741	int val;
 742	int err;
 743
 744	switch (cmd) {
 745	case PPPIOCGMRU:
 746		err = -ENXIO;
 747		if (!(sk->sk_state & PPPOX_CONNECTED))
 748			break;
 749
 750		err = -EFAULT;
 751		if (put_user(po->pppoe_dev->mtu -
 752			     sizeof(struct pppoe_hdr) -
 753			     PPP_HDRLEN,
 754			     (int __user *)arg))
 755			break;
 756		err = 0;
 757		break;
 758
 759	case PPPIOCSMRU:
 760		err = -ENXIO;
 761		if (!(sk->sk_state & PPPOX_CONNECTED))
 762			break;
 763
 764		err = -EFAULT;
 765		if (get_user(val, (int __user *)arg))
 766			break;
 767
 768		if (val < (po->pppoe_dev->mtu
 769			   - sizeof(struct pppoe_hdr)
 770			   - PPP_HDRLEN))
 771			err = 0;
 772		else
 773			err = -EINVAL;
 774		break;
 775
 776	case PPPIOCSFLAGS:
 777		err = -EFAULT;
 778		if (get_user(val, (int __user *)arg))
 779			break;
 780		err = 0;
 781		break;
 782
 783	case PPPOEIOCSFWD:
 784	{
 785		struct pppox_sock *relay_po;
 786
 787		err = -EBUSY;
 788		if (sk->sk_state & (PPPOX_BOUND | PPPOX_DEAD))
 789			break;
 790
 791		err = -ENOTCONN;
 792		if (!(sk->sk_state & PPPOX_CONNECTED))
 793			break;
 794
 795		/* PPPoE address from the user specifies an outbound
 796		   PPPoE address which frames are forwarded to */
 797		err = -EFAULT;
 798		if (copy_from_user(&po->pppoe_relay,
 799				   (void __user *)arg,
 800				   sizeof(struct sockaddr_pppox)))
 801			break;
 802
 803		err = -EINVAL;
 804		if (po->pppoe_relay.sa_family != AF_PPPOX ||
 805		    po->pppoe_relay.sa_protocol != PX_PROTO_OE)
 806			break;
 807
 808		/* Check that the socket referenced by the address
 809		   actually exists. */
 810		relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
 811		if (!relay_po)
 812			break;
 813
 814		sock_put(sk_pppox(relay_po));
 815		sk->sk_state |= PPPOX_RELAY;
 816		err = 0;
 817		break;
 818	}
 819
 820	case PPPOEIOCDFWD:
 821		err = -EALREADY;
 822		if (!(sk->sk_state & PPPOX_RELAY))
 823			break;
 824
 825		sk->sk_state &= ~PPPOX_RELAY;
 826		err = 0;
 827		break;
 828
 829	default:
 830		err = -ENOTTY;
 831	}
 832
 833	return err;
 834}
 835
 836static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
 837			 size_t total_len)
 838{
 839	struct sk_buff *skb;
 840	struct sock *sk = sock->sk;
 841	struct pppox_sock *po = pppox_sk(sk);
 842	int error;
 843	struct pppoe_hdr hdr;
 844	struct pppoe_hdr *ph;
 845	struct net_device *dev;
 846	char *start;
 847	int hlen;
 848
 849	lock_sock(sk);
 850	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
 851		error = -ENOTCONN;
 852		goto end;
 853	}
 854
 855	hdr.ver = 1;
 856	hdr.type = 1;
 857	hdr.code = 0;
 858	hdr.sid = po->num;
 859
 860	dev = po->pppoe_dev;
 861
 862	error = -EMSGSIZE;
 863	if (total_len > (dev->mtu + dev->hard_header_len))
 864		goto end;
 865
 866	hlen = LL_RESERVED_SPACE(dev);
 867	skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len +
 868			   dev->needed_tailroom, 0, GFP_KERNEL);
 869	if (!skb) {
 870		error = -ENOMEM;
 871		goto end;
 872	}
 873
 874	/* Reserve space for headers. */
 875	skb_reserve(skb, hlen);
 876	skb_reset_network_header(skb);
 877
 878	skb->dev = dev;
 879
 880	skb->priority = READ_ONCE(sk->sk_priority);
 881	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 882
 883	ph = skb_put(skb, total_len + sizeof(struct pppoe_hdr));
 884	start = (char *)&ph->tag[0];
 885
 886	error = memcpy_from_msg(start, m, total_len);
 887	if (error < 0) {
 888		kfree_skb(skb);
 889		goto end;
 890	}
 891
 892	error = total_len;
 893	dev_hard_header(skb, dev, ETH_P_PPP_SES,
 894			po->pppoe_pa.remote, NULL, total_len);
 895
 896	memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
 897
 898	ph->length = htons(total_len);
 899
 900	dev_queue_xmit(skb);
 901
 902end:
 903	release_sock(sk);
 904	return error;
 905}
 906
 907/************************************************************************
 908 *
 909 * xmit function for internal use.
 910 *
 911 ***********************************************************************/
 912static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
 913{
 914	struct pppox_sock *po = pppox_sk(sk);
 915	struct net_device *dev = po->pppoe_dev;
 916	struct pppoe_hdr *ph;
 917	int data_len = skb->len;
 918
 919	/* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
 920	 * xmit operations conclude prior to an unregistration call.  Thus
 921	 * sk->sk_state cannot change, so we don't need to do lock_sock().
 922	 * But, we also can't do a lock_sock since that introduces a potential
 923	 * deadlock as we'd reverse the lock ordering used when calling
 924	 * ppp_unregister_channel().
 925	 */
 926
 927	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 928		goto abort;
 929
 930	if (!dev)
 931		goto abort;
 932
 933	/* Copy the data if there is no space for the header or if it's
 934	 * read-only.
 935	 */
 936	if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph)))
 937		goto abort;
 938
 939	__skb_push(skb, sizeof(*ph));
 940	skb_reset_network_header(skb);
 941
 942	ph = pppoe_hdr(skb);
 943	ph->ver	= 1;
 944	ph->type = 1;
 945	ph->code = 0;
 946	ph->sid	= po->num;
 947	ph->length = htons(data_len);
 948
 949	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 950	skb->dev = dev;
 951
 952	dev_hard_header(skb, dev, ETH_P_PPP_SES,
 953			po->pppoe_pa.remote, NULL, data_len);
 954
 955	dev_queue_xmit(skb);
 956	return 1;
 957
 958abort:
 959	kfree_skb(skb);
 960	return 1;
 961}
 962
 963/************************************************************************
 964 *
 965 * xmit function called by generic PPP driver
 966 * sends PPP frame over PPPoE socket
 967 *
 968 ***********************************************************************/
 969static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 970{
 971	struct sock *sk = chan->private;
 972	return __pppoe_xmit(sk, skb);
 973}
 974
 975static int pppoe_fill_forward_path(struct net_device_path_ctx *ctx,
 976				   struct net_device_path *path,
 977				   const struct ppp_channel *chan)
 978{
 979	struct sock *sk = chan->private;
 980	struct pppox_sock *po = pppox_sk(sk);
 981	struct net_device *dev = po->pppoe_dev;
 982
 983	if (sock_flag(sk, SOCK_DEAD) ||
 984	    !(sk->sk_state & PPPOX_CONNECTED) || !dev)
 985		return -1;
 986
 987	path->type = DEV_PATH_PPPOE;
 988	path->encap.proto = htons(ETH_P_PPP_SES);
 989	path->encap.id = be16_to_cpu(po->num);
 990	memcpy(path->encap.h_dest, po->pppoe_pa.remote, ETH_ALEN);
 991	memcpy(ctx->daddr, po->pppoe_pa.remote, ETH_ALEN);
 992	path->dev = ctx->dev;
 993	ctx->dev = dev;
 994
 995	return 0;
 996}
 997
 998static const struct ppp_channel_ops pppoe_chan_ops = {
 999	.start_xmit = pppoe_xmit,
1000	.fill_forward_path = pppoe_fill_forward_path,
1001};
1002
1003static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
1004			 size_t total_len, int flags)
1005{
1006	struct sock *sk = sock->sk;
1007	struct sk_buff *skb;
1008	int error = 0;
1009
1010	if (sk->sk_state & PPPOX_BOUND)
1011		return -EIO;
 
 
1012
1013	skb = skb_recv_datagram(sk, flags, &error);
1014	if (!skb)
1015		return error;
 
1016
1017	total_len = min_t(size_t, total_len, skb->len);
1018	error = skb_copy_datagram_msg(skb, 0, m, total_len);
1019	if (error == 0) {
1020		consume_skb(skb);
1021		return total_len;
 
 
1022	}
1023
1024	kfree_skb(skb);
 
1025	return error;
1026}
1027
1028#ifdef CONFIG_PROC_FS
1029static int pppoe_seq_show(struct seq_file *seq, void *v)
1030{
1031	struct pppox_sock *po;
1032	char *dev_name;
1033
1034	if (v == SEQ_START_TOKEN) {
1035		seq_puts(seq, "Id       Address              Device\n");
1036		goto out;
1037	}
1038
1039	po = v;
1040	dev_name = po->pppoe_pa.dev;
1041
1042	seq_printf(seq, "%08X %pM %8s\n",
1043		po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
1044out:
1045	return 0;
1046}
1047
1048static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
1049{
1050	struct pppox_sock *po;
1051	int i;
1052
1053	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
1054		po = pn->hash_table[i];
1055		while (po) {
1056			if (!pos--)
1057				goto out;
1058			po = po->next;
1059		}
1060	}
1061
1062out:
1063	return po;
1064}
1065
1066static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1067	__acquires(pn->hash_lock)
1068{
1069	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1070	loff_t l = *pos;
1071
1072	read_lock_bh(&pn->hash_lock);
1073	return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
1074}
1075
1076static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1077{
1078	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1079	struct pppox_sock *po;
1080
1081	++*pos;
1082	if (v == SEQ_START_TOKEN) {
1083		po = pppoe_get_idx(pn, 0);
1084		goto out;
1085	}
1086	po = v;
1087	if (po->next)
1088		po = po->next;
1089	else {
1090		int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1091
1092		po = NULL;
1093		while (++hash < PPPOE_HASH_SIZE) {
1094			po = pn->hash_table[hash];
1095			if (po)
1096				break;
1097		}
1098	}
1099
1100out:
1101	return po;
1102}
1103
1104static void pppoe_seq_stop(struct seq_file *seq, void *v)
1105	__releases(pn->hash_lock)
1106{
1107	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1108	read_unlock_bh(&pn->hash_lock);
1109}
1110
1111static const struct seq_operations pppoe_seq_ops = {
1112	.start		= pppoe_seq_start,
1113	.next		= pppoe_seq_next,
1114	.stop		= pppoe_seq_stop,
1115	.show		= pppoe_seq_show,
1116};
1117#endif /* CONFIG_PROC_FS */
1118
1119static const struct proto_ops pppoe_ops = {
1120	.family		= AF_PPPOX,
1121	.owner		= THIS_MODULE,
1122	.release	= pppoe_release,
1123	.bind		= sock_no_bind,
1124	.connect	= pppoe_connect,
1125	.socketpair	= sock_no_socketpair,
1126	.accept		= sock_no_accept,
1127	.getname	= pppoe_getname,
1128	.poll		= datagram_poll,
1129	.listen		= sock_no_listen,
1130	.shutdown	= sock_no_shutdown,
 
 
1131	.sendmsg	= pppoe_sendmsg,
1132	.recvmsg	= pppoe_recvmsg,
1133	.mmap		= sock_no_mmap,
1134	.ioctl		= pppox_ioctl,
1135#ifdef CONFIG_COMPAT
1136	.compat_ioctl	= pppox_compat_ioctl,
1137#endif
1138};
1139
1140static const struct pppox_proto pppoe_proto = {
1141	.create	= pppoe_create,
1142	.ioctl	= pppoe_ioctl,
1143	.owner	= THIS_MODULE,
1144};
1145
1146static __net_init int pppoe_init_net(struct net *net)
1147{
1148	struct pppoe_net *pn = pppoe_pernet(net);
1149	struct proc_dir_entry *pde;
1150
1151	rwlock_init(&pn->hash_lock);
1152
1153	pde = proc_create_net("pppoe", 0444, net->proc_net,
1154			&pppoe_seq_ops, sizeof(struct seq_net_private));
1155#ifdef CONFIG_PROC_FS
1156	if (!pde)
1157		return -ENOMEM;
1158#endif
1159
1160	return 0;
1161}
1162
1163static __net_exit void pppoe_exit_net(struct net *net)
1164{
1165	remove_proc_entry("pppoe", net->proc_net);
1166}
1167
1168static struct pernet_operations pppoe_net_ops = {
1169	.init = pppoe_init_net,
1170	.exit = pppoe_exit_net,
1171	.id   = &pppoe_net_id,
1172	.size = sizeof(struct pppoe_net),
1173};
1174
1175static int __init pppoe_init(void)
1176{
1177	int err;
1178
1179	err = register_pernet_device(&pppoe_net_ops);
1180	if (err)
1181		goto out;
1182
1183	err = proto_register(&pppoe_sk_proto, 0);
1184	if (err)
1185		goto out_unregister_net_ops;
1186
1187	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1188	if (err)
1189		goto out_unregister_pppoe_proto;
1190
1191	dev_add_pack(&pppoes_ptype);
1192	dev_add_pack(&pppoed_ptype);
1193	register_netdevice_notifier(&pppoe_notifier);
1194
1195	return 0;
1196
1197out_unregister_pppoe_proto:
1198	proto_unregister(&pppoe_sk_proto);
1199out_unregister_net_ops:
1200	unregister_pernet_device(&pppoe_net_ops);
1201out:
1202	return err;
1203}
1204
1205static void __exit pppoe_exit(void)
1206{
1207	unregister_netdevice_notifier(&pppoe_notifier);
1208	dev_remove_pack(&pppoed_ptype);
1209	dev_remove_pack(&pppoes_ptype);
1210	unregister_pppox_proto(PX_PROTO_OE);
1211	proto_unregister(&pppoe_sk_proto);
1212	unregister_pernet_device(&pppoe_net_ops);
1213}
1214
1215module_init(pppoe_init);
1216module_exit(pppoe_exit);
1217
1218MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1219MODULE_DESCRIPTION("PPP over Ethernet driver");
1220MODULE_LICENSE("GPL");
1221MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OE);
v5.4
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/** -*- linux-c -*- ***********************************************************
   3 * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
   4 *
   5 * PPPoX --- Generic PPP encapsulation socket family
   6 * PPPoE --- PPP over Ethernet (RFC 2516)
   7 *
   8 * Version:	0.7.0
   9 *
  10 * 070228 :	Fix to allow multiple sessions with same remote MAC and same
  11 *		session id by including the local device ifindex in the
  12 *		tuple identifying a session. This also ensures packets can't
  13 *		be injected into a session from interfaces other than the one
  14 *		specified by userspace. Florian Zumbiehl <florz@florz.de>
  15 *		(Oh, BTW, this one is YYMMDD, in case you were wondering ...)
  16 * 220102 :	Fix module use count on failure in pppoe_create, pppox_sk -acme
  17 * 030700 :	Fixed connect logic to allow for disconnect.
  18 * 270700 :	Fixed potential SMP problems; we must protect against
  19 *		simultaneous invocation of ppp_input
  20 *		and ppp_unregister_channel.
  21 * 040800 :	Respect reference count mechanisms on net-devices.
  22 * 200800 :	fix kfree(skb) in pppoe_rcv (acme)
  23 *		Module reference count is decremented in the right spot now,
  24 *		guards against sock_put not actually freeing the sk
  25 *		in pppoe_release.
  26 * 051000 :	Initialization cleanup.
  27 * 111100 :	Fix recvmsg.
  28 * 050101 :	Fix PADT procesing.
  29 * 140501 :	Use pppoe_rcv_core to handle all backlog. (Alexey)
  30 * 170701 :	Do not lock_sock with rwlock held. (DaveM)
  31 *		Ignore discovery frames if user has socket
  32 *		locked. (DaveM)
  33 *		Ignore return value of dev_queue_xmit in __pppoe_xmit
  34 *		or else we may kfree an SKB twice. (DaveM)
  35 * 190701 :	When doing copies of skb's in __pppoe_xmit, always delete
  36 *		the original skb that was passed in on success, never on
  37 *		failure.  Delete the copy of the skb on failure to avoid
  38 *		a memory leak.
  39 * 081001 :	Misc. cleanup (licence string, non-blocking, prevent
  40 *		reference of device on close).
  41 * 121301 :	New ppp channels interface; cannot unregister a channel
  42 *		from interrupts.  Thus, we mark the socket as a ZOMBIE
  43 *		and do the unregistration later.
  44 * 081002 :	seq_file support for proc stuff -acme
  45 * 111602 :	Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
  46 *		as version 0.7.  Spacing cleanup.
  47 * Author:	Michal Ostrowski <mostrows@speakeasy.net>
  48 * Contributors:
  49 * 		Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  50 *		David S. Miller (davem@redhat.com)
  51 *
  52 * License:
  53 */
  54
  55#include <linux/string.h>
  56#include <linux/module.h>
  57#include <linux/kernel.h>
  58#include <linux/slab.h>
  59#include <linux/errno.h>
  60#include <linux/netdevice.h>
  61#include <linux/net.h>
  62#include <linux/inetdevice.h>
  63#include <linux/etherdevice.h>
  64#include <linux/skbuff.h>
  65#include <linux/init.h>
  66#include <linux/if_ether.h>
  67#include <linux/if_pppox.h>
  68#include <linux/ppp_channel.h>
  69#include <linux/ppp_defs.h>
  70#include <linux/ppp-ioctl.h>
  71#include <linux/notifier.h>
  72#include <linux/file.h>
  73#include <linux/proc_fs.h>
  74#include <linux/seq_file.h>
  75
  76#include <linux/nsproxy.h>
  77#include <net/net_namespace.h>
  78#include <net/netns/generic.h>
  79#include <net/sock.h>
  80
  81#include <linux/uaccess.h>
  82
  83#define PPPOE_HASH_BITS 4
  84#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
  85#define PPPOE_HASH_MASK	(PPPOE_HASH_SIZE - 1)
  86
  87static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
  88
  89static const struct proto_ops pppoe_ops;
  90static const struct ppp_channel_ops pppoe_chan_ops;
  91
  92/* per-net private data for this module */
  93static unsigned int pppoe_net_id __read_mostly;
  94struct pppoe_net {
  95	/*
  96	 * we could use _single_ hash table for all
  97	 * nets by injecting net id into the hash but
  98	 * it would increase hash chains and add
  99	 * a few additional math comparations messy
 100	 * as well, moreover in case of SMP less locking
 101	 * controversy here
 102	 */
 103	struct pppox_sock *hash_table[PPPOE_HASH_SIZE];
 104	rwlock_t hash_lock;
 105};
 106
 107/*
 108 * PPPoE could be in the following stages:
 109 * 1) Discovery stage (to obtain remote MAC and Session ID)
 110 * 2) Session stage (MAC and SID are known)
 111 *
 112 * Ethernet frames have a special tag for this but
 113 * we use simpler approach based on session id
 114 */
 115static inline bool stage_session(__be16 sid)
 116{
 117	return sid != 0;
 118}
 119
 120static inline struct pppoe_net *pppoe_pernet(struct net *net)
 121{
 122	BUG_ON(!net);
 123
 124	return net_generic(net, pppoe_net_id);
 125}
 126
 127static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
 128{
 129	return a->sid == b->sid && ether_addr_equal(a->remote, b->remote);
 130}
 131
 132static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
 133{
 134	return a->sid == sid && ether_addr_equal(a->remote, addr);
 135}
 136
 137#if 8 % PPPOE_HASH_BITS
 138#error 8 must be a multiple of PPPOE_HASH_BITS
 139#endif
 140
 141static int hash_item(__be16 sid, unsigned char *addr)
 142{
 143	unsigned char hash = 0;
 144	unsigned int i;
 145
 146	for (i = 0; i < ETH_ALEN; i++)
 147		hash ^= addr[i];
 148	for (i = 0; i < sizeof(sid_t) * 8; i += 8)
 149		hash ^= (__force __u32)sid >> i;
 150	for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
 151		hash ^= hash >> i;
 152
 153	return hash & PPPOE_HASH_MASK;
 154}
 155
 156/**********************************************************************
 157 *
 158 *  Set/get/delete/rehash items  (internal versions)
 159 *
 160 **********************************************************************/
 161static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
 162				unsigned char *addr, int ifindex)
 163{
 164	int hash = hash_item(sid, addr);
 165	struct pppox_sock *ret;
 166
 167	ret = pn->hash_table[hash];
 168	while (ret) {
 169		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 170		    ret->pppoe_ifindex == ifindex)
 171			return ret;
 172
 173		ret = ret->next;
 174	}
 175
 176	return NULL;
 177}
 178
 179static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
 180{
 181	int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
 182	struct pppox_sock *ret;
 183
 184	ret = pn->hash_table[hash];
 185	while (ret) {
 186		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
 187		    ret->pppoe_ifindex == po->pppoe_ifindex)
 188			return -EALREADY;
 189
 190		ret = ret->next;
 191	}
 192
 193	po->next = pn->hash_table[hash];
 194	pn->hash_table[hash] = po;
 195
 196	return 0;
 197}
 198
 199static void __delete_item(struct pppoe_net *pn, __be16 sid,
 200					char *addr, int ifindex)
 201{
 202	int hash = hash_item(sid, addr);
 203	struct pppox_sock *ret, **src;
 204
 205	ret = pn->hash_table[hash];
 206	src = &pn->hash_table[hash];
 207
 208	while (ret) {
 209		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
 210		    ret->pppoe_ifindex == ifindex) {
 211			*src = ret->next;
 212			break;
 213		}
 214
 215		src = &ret->next;
 216		ret = ret->next;
 217	}
 218}
 219
 220/**********************************************************************
 221 *
 222 *  Set/get/delete/rehash items
 223 *
 224 **********************************************************************/
 225static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
 226					unsigned char *addr, int ifindex)
 227{
 228	struct pppox_sock *po;
 229
 230	read_lock_bh(&pn->hash_lock);
 231	po = __get_item(pn, sid, addr, ifindex);
 232	if (po)
 233		sock_hold(sk_pppox(po));
 234	read_unlock_bh(&pn->hash_lock);
 235
 236	return po;
 237}
 238
 239static inline struct pppox_sock *get_item_by_addr(struct net *net,
 240						struct sockaddr_pppox *sp)
 241{
 242	struct net_device *dev;
 243	struct pppoe_net *pn;
 244	struct pppox_sock *pppox_sock = NULL;
 245
 246	int ifindex;
 247
 248	rcu_read_lock();
 249	dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
 250	if (dev) {
 251		ifindex = dev->ifindex;
 252		pn = pppoe_pernet(net);
 253		pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
 254				sp->sa_addr.pppoe.remote, ifindex);
 255	}
 256	rcu_read_unlock();
 257	return pppox_sock;
 258}
 259
 260static inline void delete_item(struct pppoe_net *pn, __be16 sid,
 261					char *addr, int ifindex)
 262{
 263	write_lock_bh(&pn->hash_lock);
 264	__delete_item(pn, sid, addr, ifindex);
 265	write_unlock_bh(&pn->hash_lock);
 266}
 267
 268/***************************************************************************
 269 *
 270 *  Handler for device events.
 271 *  Certain device events require that sockets be unconnected.
 272 *
 273 **************************************************************************/
 274
 275static void pppoe_flush_dev(struct net_device *dev)
 276{
 277	struct pppoe_net *pn;
 278	int i;
 279
 280	pn = pppoe_pernet(dev_net(dev));
 281	write_lock_bh(&pn->hash_lock);
 282	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 283		struct pppox_sock *po = pn->hash_table[i];
 284		struct sock *sk;
 285
 286		while (po) {
 287			while (po && po->pppoe_dev != dev) {
 288				po = po->next;
 289			}
 290
 291			if (!po)
 292				break;
 293
 294			sk = sk_pppox(po);
 295
 296			/* We always grab the socket lock, followed by the
 297			 * hash_lock, in that order.  Since we should hold the
 298			 * sock lock while doing any unbinding, we need to
 299			 * release the lock we're holding.  Hold a reference to
 300			 * the sock so it doesn't disappear as we're jumping
 301			 * between locks.
 302			 */
 303
 304			sock_hold(sk);
 305			write_unlock_bh(&pn->hash_lock);
 306			lock_sock(sk);
 307
 308			if (po->pppoe_dev == dev &&
 309			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
 310				pppox_unbind_sock(sk);
 311				sk->sk_state_change(sk);
 312				po->pppoe_dev = NULL;
 313				dev_put(dev);
 314			}
 315
 316			release_sock(sk);
 317			sock_put(sk);
 318
 319			/* Restart the process from the start of the current
 320			 * hash chain. We dropped locks so the world may have
 321			 * change from underneath us.
 322			 */
 323
 324			BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
 325			write_lock_bh(&pn->hash_lock);
 326			po = pn->hash_table[i];
 327		}
 328	}
 329	write_unlock_bh(&pn->hash_lock);
 330}
 331
 332static int pppoe_device_event(struct notifier_block *this,
 333			      unsigned long event, void *ptr)
 334{
 335	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 336
 337	/* Only look at sockets that are using this specific device. */
 338	switch (event) {
 339	case NETDEV_CHANGEADDR:
 340	case NETDEV_CHANGEMTU:
 341		/* A change in mtu or address is a bad thing, requiring
 342		 * LCP re-negotiation.
 343		 */
 344
 345	case NETDEV_GOING_DOWN:
 346	case NETDEV_DOWN:
 347		/* Find every socket on this device and kill it. */
 348		pppoe_flush_dev(dev);
 349		break;
 350
 351	default:
 352		break;
 353	}
 354
 355	return NOTIFY_DONE;
 356}
 357
 358static struct notifier_block pppoe_notifier = {
 359	.notifier_call = pppoe_device_event,
 360};
 361
 362/************************************************************************
 363 *
 364 * Do the real work of receiving a PPPoE Session frame.
 365 *
 366 ***********************************************************************/
 367static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
 368{
 369	struct pppox_sock *po = pppox_sk(sk);
 370	struct pppox_sock *relay_po;
 371
 372	/* Backlog receive. Semantics of backlog rcv preclude any code from
 373	 * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
 374	 * can't change.
 375	 */
 376
 377	if (skb->pkt_type == PACKET_OTHERHOST)
 378		goto abort_kfree;
 379
 380	if (sk->sk_state & PPPOX_BOUND) {
 381		ppp_input(&po->chan, skb);
 382	} else if (sk->sk_state & PPPOX_RELAY) {
 383		relay_po = get_item_by_addr(sock_net(sk),
 384					    &po->pppoe_relay);
 385		if (relay_po == NULL)
 386			goto abort_kfree;
 387
 388		if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
 389			goto abort_put;
 390
 391		if (!__pppoe_xmit(sk_pppox(relay_po), skb))
 392			goto abort_put;
 393
 394		sock_put(sk_pppox(relay_po));
 395	} else {
 396		if (sock_queue_rcv_skb(sk, skb))
 397			goto abort_kfree;
 398	}
 399
 400	return NET_RX_SUCCESS;
 401
 402abort_put:
 403	sock_put(sk_pppox(relay_po));
 404
 405abort_kfree:
 406	kfree_skb(skb);
 407	return NET_RX_DROP;
 408}
 409
 410/************************************************************************
 411 *
 412 * Receive wrapper called in BH context.
 413 *
 414 ***********************************************************************/
 415static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
 416		     struct packet_type *pt, struct net_device *orig_dev)
 417{
 418	struct pppoe_hdr *ph;
 419	struct pppox_sock *po;
 420	struct pppoe_net *pn;
 421	int len;
 422
 423	skb = skb_share_check(skb, GFP_ATOMIC);
 424	if (!skb)
 425		goto out;
 426
 427	if (skb_mac_header_len(skb) < ETH_HLEN)
 428		goto drop;
 429
 430	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 431		goto drop;
 432
 433	ph = pppoe_hdr(skb);
 434	len = ntohs(ph->length);
 435
 436	skb_pull_rcsum(skb, sizeof(*ph));
 437	if (skb->len < len)
 438		goto drop;
 439
 440	if (pskb_trim_rcsum(skb, len))
 441		goto drop;
 442
 443	ph = pppoe_hdr(skb);
 444	pn = pppoe_pernet(dev_net(dev));
 445
 446	/* Note that get_item does a sock_hold(), so sk_pppox(po)
 447	 * is known to be safe.
 448	 */
 449	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 450	if (!po)
 451		goto drop;
 452
 453	return sk_receive_skb(sk_pppox(po), skb, 0);
 454
 455drop:
 456	kfree_skb(skb);
 457out:
 458	return NET_RX_DROP;
 459}
 460
 461static void pppoe_unbind_sock_work(struct work_struct *work)
 462{
 463	struct pppox_sock *po = container_of(work, struct pppox_sock,
 464					     proto.pppoe.padt_work);
 465	struct sock *sk = sk_pppox(po);
 466
 467	lock_sock(sk);
 468	if (po->pppoe_dev) {
 469		dev_put(po->pppoe_dev);
 470		po->pppoe_dev = NULL;
 471	}
 472	pppox_unbind_sock(sk);
 473	release_sock(sk);
 474	sock_put(sk);
 475}
 476
 477/************************************************************************
 478 *
 479 * Receive a PPPoE Discovery frame.
 480 * This is solely for detection of PADT frames
 481 *
 482 ***********************************************************************/
 483static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
 484			  struct packet_type *pt, struct net_device *orig_dev)
 485
 486{
 487	struct pppoe_hdr *ph;
 488	struct pppox_sock *po;
 489	struct pppoe_net *pn;
 490
 491	skb = skb_share_check(skb, GFP_ATOMIC);
 492	if (!skb)
 493		goto out;
 494
 
 
 
 495	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 496		goto abort;
 497
 498	ph = pppoe_hdr(skb);
 499	if (ph->code != PADT_CODE)
 500		goto abort;
 501
 502	pn = pppoe_pernet(dev_net(dev));
 503	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
 504	if (po)
 505		if (!schedule_work(&po->proto.pppoe.padt_work))
 506			sock_put(sk_pppox(po));
 507
 508abort:
 509	kfree_skb(skb);
 510out:
 511	return NET_RX_SUCCESS; /* Lies... :-) */
 512}
 513
 514static struct packet_type pppoes_ptype __read_mostly = {
 515	.type	= cpu_to_be16(ETH_P_PPP_SES),
 516	.func	= pppoe_rcv,
 517};
 518
 519static struct packet_type pppoed_ptype __read_mostly = {
 520	.type	= cpu_to_be16(ETH_P_PPP_DISC),
 521	.func	= pppoe_disc_rcv,
 522};
 523
 524static struct proto pppoe_sk_proto __read_mostly = {
 525	.name	  = "PPPOE",
 526	.owner	  = THIS_MODULE,
 527	.obj_size = sizeof(struct pppox_sock),
 528};
 529
 530/***********************************************************************
 531 *
 532 * Initialize a new struct sock.
 533 *
 534 **********************************************************************/
 535static int pppoe_create(struct net *net, struct socket *sock, int kern)
 536{
 537	struct sock *sk;
 538
 539	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, kern);
 540	if (!sk)
 541		return -ENOMEM;
 542
 543	sock_init_data(sock, sk);
 544
 545	sock->state	= SS_UNCONNECTED;
 546	sock->ops	= &pppoe_ops;
 547
 548	sk->sk_backlog_rcv	= pppoe_rcv_core;
 549	sk->sk_state		= PPPOX_NONE;
 550	sk->sk_type		= SOCK_STREAM;
 551	sk->sk_family		= PF_PPPOX;
 552	sk->sk_protocol		= PX_PROTO_OE;
 553
 554	INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
 555		  pppoe_unbind_sock_work);
 556
 557	return 0;
 558}
 559
 560static int pppoe_release(struct socket *sock)
 561{
 562	struct sock *sk = sock->sk;
 563	struct pppox_sock *po;
 564	struct pppoe_net *pn;
 565	struct net *net = NULL;
 566
 567	if (!sk)
 568		return 0;
 569
 570	lock_sock(sk);
 571	if (sock_flag(sk, SOCK_DEAD)) {
 572		release_sock(sk);
 573		return -EBADF;
 574	}
 575
 576	po = pppox_sk(sk);
 577
 578	if (po->pppoe_dev) {
 579		dev_put(po->pppoe_dev);
 580		po->pppoe_dev = NULL;
 581	}
 582
 583	pppox_unbind_sock(sk);
 584
 585	/* Signal the death of the socket. */
 586	sk->sk_state = PPPOX_DEAD;
 587
 588	net = sock_net(sk);
 589	pn = pppoe_pernet(net);
 590
 591	/*
 592	 * protect "po" from concurrent updates
 593	 * on pppoe_flush_dev
 594	 */
 595	delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
 596		    po->pppoe_ifindex);
 597
 598	sock_orphan(sk);
 599	sock->sk = NULL;
 600
 601	skb_queue_purge(&sk->sk_receive_queue);
 602	release_sock(sk);
 603	sock_put(sk);
 604
 605	return 0;
 606}
 607
 608static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
 609		  int sockaddr_len, int flags)
 610{
 611	struct sock *sk = sock->sk;
 612	struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
 613	struct pppox_sock *po = pppox_sk(sk);
 614	struct net_device *dev = NULL;
 615	struct pppoe_net *pn;
 616	struct net *net = NULL;
 617	int error;
 618
 619	lock_sock(sk);
 620
 621	error = -EINVAL;
 622
 623	if (sockaddr_len != sizeof(struct sockaddr_pppox))
 624		goto end;
 625
 626	if (sp->sa_protocol != PX_PROTO_OE)
 627		goto end;
 628
 629	/* Check for already bound sockets */
 630	error = -EBUSY;
 631	if ((sk->sk_state & PPPOX_CONNECTED) &&
 632	     stage_session(sp->sa_addr.pppoe.sid))
 633		goto end;
 634
 635	/* Check for already disconnected sockets, on attempts to disconnect */
 636	error = -EALREADY;
 637	if ((sk->sk_state & PPPOX_DEAD) &&
 638	     !stage_session(sp->sa_addr.pppoe.sid))
 639		goto end;
 640
 641	error = 0;
 642
 643	/* Delete the old binding */
 644	if (stage_session(po->pppoe_pa.sid)) {
 645		pppox_unbind_sock(sk);
 646		pn = pppoe_pernet(sock_net(sk));
 647		delete_item(pn, po->pppoe_pa.sid,
 648			    po->pppoe_pa.remote, po->pppoe_ifindex);
 649		if (po->pppoe_dev) {
 650			dev_put(po->pppoe_dev);
 651			po->pppoe_dev = NULL;
 652		}
 653
 654		po->pppoe_ifindex = 0;
 655		memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
 656		memset(&po->pppoe_relay, 0, sizeof(po->pppoe_relay));
 657		memset(&po->chan, 0, sizeof(po->chan));
 658		po->next = NULL;
 659		po->num = 0;
 660
 661		sk->sk_state = PPPOX_NONE;
 662	}
 663
 664	/* Re-bind in session stage only */
 665	if (stage_session(sp->sa_addr.pppoe.sid)) {
 666		error = -ENODEV;
 667		net = sock_net(sk);
 668		dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
 669		if (!dev)
 670			goto err_put;
 671
 672		po->pppoe_dev = dev;
 673		po->pppoe_ifindex = dev->ifindex;
 674		pn = pppoe_pernet(net);
 675		if (!(dev->flags & IFF_UP)) {
 676			goto err_put;
 677		}
 678
 679		memcpy(&po->pppoe_pa,
 680		       &sp->sa_addr.pppoe,
 681		       sizeof(struct pppoe_addr));
 682
 683		write_lock_bh(&pn->hash_lock);
 684		error = __set_item(pn, po);
 685		write_unlock_bh(&pn->hash_lock);
 686		if (error < 0)
 687			goto err_put;
 688
 689		po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
 690				   dev->hard_header_len);
 691
 692		po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
 693		po->chan.private = sk;
 694		po->chan.ops = &pppoe_chan_ops;
 695
 696		error = ppp_register_net_channel(dev_net(dev), &po->chan);
 697		if (error) {
 698			delete_item(pn, po->pppoe_pa.sid,
 699				    po->pppoe_pa.remote, po->pppoe_ifindex);
 700			goto err_put;
 701		}
 702
 703		sk->sk_state = PPPOX_CONNECTED;
 704	}
 705
 706	po->num = sp->sa_addr.pppoe.sid;
 707
 708end:
 709	release_sock(sk);
 710	return error;
 711err_put:
 712	if (po->pppoe_dev) {
 713		dev_put(po->pppoe_dev);
 714		po->pppoe_dev = NULL;
 715	}
 716	goto end;
 717}
 718
 719static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
 720		  int peer)
 721{
 722	int len = sizeof(struct sockaddr_pppox);
 723	struct sockaddr_pppox sp;
 724
 725	sp.sa_family	= AF_PPPOX;
 726	sp.sa_protocol	= PX_PROTO_OE;
 727	memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
 728	       sizeof(struct pppoe_addr));
 729
 730	memcpy(uaddr, &sp, len);
 731
 732	return len;
 733}
 734
 735static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
 736		unsigned long arg)
 737{
 738	struct sock *sk = sock->sk;
 739	struct pppox_sock *po = pppox_sk(sk);
 740	int val;
 741	int err;
 742
 743	switch (cmd) {
 744	case PPPIOCGMRU:
 745		err = -ENXIO;
 746		if (!(sk->sk_state & PPPOX_CONNECTED))
 747			break;
 748
 749		err = -EFAULT;
 750		if (put_user(po->pppoe_dev->mtu -
 751			     sizeof(struct pppoe_hdr) -
 752			     PPP_HDRLEN,
 753			     (int __user *)arg))
 754			break;
 755		err = 0;
 756		break;
 757
 758	case PPPIOCSMRU:
 759		err = -ENXIO;
 760		if (!(sk->sk_state & PPPOX_CONNECTED))
 761			break;
 762
 763		err = -EFAULT;
 764		if (get_user(val, (int __user *)arg))
 765			break;
 766
 767		if (val < (po->pppoe_dev->mtu
 768			   - sizeof(struct pppoe_hdr)
 769			   - PPP_HDRLEN))
 770			err = 0;
 771		else
 772			err = -EINVAL;
 773		break;
 774
 775	case PPPIOCSFLAGS:
 776		err = -EFAULT;
 777		if (get_user(val, (int __user *)arg))
 778			break;
 779		err = 0;
 780		break;
 781
 782	case PPPOEIOCSFWD:
 783	{
 784		struct pppox_sock *relay_po;
 785
 786		err = -EBUSY;
 787		if (sk->sk_state & (PPPOX_BOUND | PPPOX_DEAD))
 788			break;
 789
 790		err = -ENOTCONN;
 791		if (!(sk->sk_state & PPPOX_CONNECTED))
 792			break;
 793
 794		/* PPPoE address from the user specifies an outbound
 795		   PPPoE address which frames are forwarded to */
 796		err = -EFAULT;
 797		if (copy_from_user(&po->pppoe_relay,
 798				   (void __user *)arg,
 799				   sizeof(struct sockaddr_pppox)))
 800			break;
 801
 802		err = -EINVAL;
 803		if (po->pppoe_relay.sa_family != AF_PPPOX ||
 804		    po->pppoe_relay.sa_protocol != PX_PROTO_OE)
 805			break;
 806
 807		/* Check that the socket referenced by the address
 808		   actually exists. */
 809		relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
 810		if (!relay_po)
 811			break;
 812
 813		sock_put(sk_pppox(relay_po));
 814		sk->sk_state |= PPPOX_RELAY;
 815		err = 0;
 816		break;
 817	}
 818
 819	case PPPOEIOCDFWD:
 820		err = -EALREADY;
 821		if (!(sk->sk_state & PPPOX_RELAY))
 822			break;
 823
 824		sk->sk_state &= ~PPPOX_RELAY;
 825		err = 0;
 826		break;
 827
 828	default:
 829		err = -ENOTTY;
 830	}
 831
 832	return err;
 833}
 834
 835static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
 836			 size_t total_len)
 837{
 838	struct sk_buff *skb;
 839	struct sock *sk = sock->sk;
 840	struct pppox_sock *po = pppox_sk(sk);
 841	int error;
 842	struct pppoe_hdr hdr;
 843	struct pppoe_hdr *ph;
 844	struct net_device *dev;
 845	char *start;
 846	int hlen;
 847
 848	lock_sock(sk);
 849	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
 850		error = -ENOTCONN;
 851		goto end;
 852	}
 853
 854	hdr.ver = 1;
 855	hdr.type = 1;
 856	hdr.code = 0;
 857	hdr.sid = po->num;
 858
 859	dev = po->pppoe_dev;
 860
 861	error = -EMSGSIZE;
 862	if (total_len > (dev->mtu + dev->hard_header_len))
 863		goto end;
 864
 865	hlen = LL_RESERVED_SPACE(dev);
 866	skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len +
 867			   dev->needed_tailroom, 0, GFP_KERNEL);
 868	if (!skb) {
 869		error = -ENOMEM;
 870		goto end;
 871	}
 872
 873	/* Reserve space for headers. */
 874	skb_reserve(skb, hlen);
 875	skb_reset_network_header(skb);
 876
 877	skb->dev = dev;
 878
 879	skb->priority = sk->sk_priority;
 880	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 881
 882	ph = skb_put(skb, total_len + sizeof(struct pppoe_hdr));
 883	start = (char *)&ph->tag[0];
 884
 885	error = memcpy_from_msg(start, m, total_len);
 886	if (error < 0) {
 887		kfree_skb(skb);
 888		goto end;
 889	}
 890
 891	error = total_len;
 892	dev_hard_header(skb, dev, ETH_P_PPP_SES,
 893			po->pppoe_pa.remote, NULL, total_len);
 894
 895	memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
 896
 897	ph->length = htons(total_len);
 898
 899	dev_queue_xmit(skb);
 900
 901end:
 902	release_sock(sk);
 903	return error;
 904}
 905
 906/************************************************************************
 907 *
 908 * xmit function for internal use.
 909 *
 910 ***********************************************************************/
 911static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
 912{
 913	struct pppox_sock *po = pppox_sk(sk);
 914	struct net_device *dev = po->pppoe_dev;
 915	struct pppoe_hdr *ph;
 916	int data_len = skb->len;
 917
 918	/* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
 919	 * xmit operations conclude prior to an unregistration call.  Thus
 920	 * sk->sk_state cannot change, so we don't need to do lock_sock().
 921	 * But, we also can't do a lock_sock since that introduces a potential
 922	 * deadlock as we'd reverse the lock ordering used when calling
 923	 * ppp_unregister_channel().
 924	 */
 925
 926	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 927		goto abort;
 928
 929	if (!dev)
 930		goto abort;
 931
 932	/* Copy the data if there is no space for the header or if it's
 933	 * read-only.
 934	 */
 935	if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph)))
 936		goto abort;
 937
 938	__skb_push(skb, sizeof(*ph));
 939	skb_reset_network_header(skb);
 940
 941	ph = pppoe_hdr(skb);
 942	ph->ver	= 1;
 943	ph->type = 1;
 944	ph->code = 0;
 945	ph->sid	= po->num;
 946	ph->length = htons(data_len);
 947
 948	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
 949	skb->dev = dev;
 950
 951	dev_hard_header(skb, dev, ETH_P_PPP_SES,
 952			po->pppoe_pa.remote, NULL, data_len);
 953
 954	dev_queue_xmit(skb);
 955	return 1;
 956
 957abort:
 958	kfree_skb(skb);
 959	return 1;
 960}
 961
 962/************************************************************************
 963 *
 964 * xmit function called by generic PPP driver
 965 * sends PPP frame over PPPoE socket
 966 *
 967 ***********************************************************************/
 968static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 969{
 970	struct sock *sk = (struct sock *)chan->private;
 971	return __pppoe_xmit(sk, skb);
 972}
 973
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 974static const struct ppp_channel_ops pppoe_chan_ops = {
 975	.start_xmit = pppoe_xmit,
 
 976};
 977
 978static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
 979			 size_t total_len, int flags)
 980{
 981	struct sock *sk = sock->sk;
 982	struct sk_buff *skb;
 983	int error = 0;
 984
 985	if (sk->sk_state & PPPOX_BOUND) {
 986		error = -EIO;
 987		goto end;
 988	}
 989
 990	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 991				flags & MSG_DONTWAIT, &error);
 992	if (error < 0)
 993		goto end;
 994
 995	if (skb) {
 996		total_len = min_t(size_t, total_len, skb->len);
 997		error = skb_copy_datagram_msg(skb, 0, m, total_len);
 998		if (error == 0) {
 999			consume_skb(skb);
1000			return total_len;
1001		}
1002	}
1003
1004	kfree_skb(skb);
1005end:
1006	return error;
1007}
1008
1009#ifdef CONFIG_PROC_FS
1010static int pppoe_seq_show(struct seq_file *seq, void *v)
1011{
1012	struct pppox_sock *po;
1013	char *dev_name;
1014
1015	if (v == SEQ_START_TOKEN) {
1016		seq_puts(seq, "Id       Address              Device\n");
1017		goto out;
1018	}
1019
1020	po = v;
1021	dev_name = po->pppoe_pa.dev;
1022
1023	seq_printf(seq, "%08X %pM %8s\n",
1024		po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
1025out:
1026	return 0;
1027}
1028
1029static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
1030{
1031	struct pppox_sock *po;
1032	int i;
1033
1034	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
1035		po = pn->hash_table[i];
1036		while (po) {
1037			if (!pos--)
1038				goto out;
1039			po = po->next;
1040		}
1041	}
1042
1043out:
1044	return po;
1045}
1046
1047static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
1048	__acquires(pn->hash_lock)
1049{
1050	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1051	loff_t l = *pos;
1052
1053	read_lock_bh(&pn->hash_lock);
1054	return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
1055}
1056
1057static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1058{
1059	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1060	struct pppox_sock *po;
1061
1062	++*pos;
1063	if (v == SEQ_START_TOKEN) {
1064		po = pppoe_get_idx(pn, 0);
1065		goto out;
1066	}
1067	po = v;
1068	if (po->next)
1069		po = po->next;
1070	else {
1071		int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
1072
1073		po = NULL;
1074		while (++hash < PPPOE_HASH_SIZE) {
1075			po = pn->hash_table[hash];
1076			if (po)
1077				break;
1078		}
1079	}
1080
1081out:
1082	return po;
1083}
1084
1085static void pppoe_seq_stop(struct seq_file *seq, void *v)
1086	__releases(pn->hash_lock)
1087{
1088	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
1089	read_unlock_bh(&pn->hash_lock);
1090}
1091
1092static const struct seq_operations pppoe_seq_ops = {
1093	.start		= pppoe_seq_start,
1094	.next		= pppoe_seq_next,
1095	.stop		= pppoe_seq_stop,
1096	.show		= pppoe_seq_show,
1097};
1098#endif /* CONFIG_PROC_FS */
1099
1100static const struct proto_ops pppoe_ops = {
1101	.family		= AF_PPPOX,
1102	.owner		= THIS_MODULE,
1103	.release	= pppoe_release,
1104	.bind		= sock_no_bind,
1105	.connect	= pppoe_connect,
1106	.socketpair	= sock_no_socketpair,
1107	.accept		= sock_no_accept,
1108	.getname	= pppoe_getname,
1109	.poll		= datagram_poll,
1110	.listen		= sock_no_listen,
1111	.shutdown	= sock_no_shutdown,
1112	.setsockopt	= sock_no_setsockopt,
1113	.getsockopt	= sock_no_getsockopt,
1114	.sendmsg	= pppoe_sendmsg,
1115	.recvmsg	= pppoe_recvmsg,
1116	.mmap		= sock_no_mmap,
1117	.ioctl		= pppox_ioctl,
1118#ifdef CONFIG_COMPAT
1119	.compat_ioctl	= pppox_compat_ioctl,
1120#endif
1121};
1122
1123static const struct pppox_proto pppoe_proto = {
1124	.create	= pppoe_create,
1125	.ioctl	= pppoe_ioctl,
1126	.owner	= THIS_MODULE,
1127};
1128
1129static __net_init int pppoe_init_net(struct net *net)
1130{
1131	struct pppoe_net *pn = pppoe_pernet(net);
1132	struct proc_dir_entry *pde;
1133
1134	rwlock_init(&pn->hash_lock);
1135
1136	pde = proc_create_net("pppoe", 0444, net->proc_net,
1137			&pppoe_seq_ops, sizeof(struct seq_net_private));
1138#ifdef CONFIG_PROC_FS
1139	if (!pde)
1140		return -ENOMEM;
1141#endif
1142
1143	return 0;
1144}
1145
1146static __net_exit void pppoe_exit_net(struct net *net)
1147{
1148	remove_proc_entry("pppoe", net->proc_net);
1149}
1150
1151static struct pernet_operations pppoe_net_ops = {
1152	.init = pppoe_init_net,
1153	.exit = pppoe_exit_net,
1154	.id   = &pppoe_net_id,
1155	.size = sizeof(struct pppoe_net),
1156};
1157
1158static int __init pppoe_init(void)
1159{
1160	int err;
1161
1162	err = register_pernet_device(&pppoe_net_ops);
1163	if (err)
1164		goto out;
1165
1166	err = proto_register(&pppoe_sk_proto, 0);
1167	if (err)
1168		goto out_unregister_net_ops;
1169
1170	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
1171	if (err)
1172		goto out_unregister_pppoe_proto;
1173
1174	dev_add_pack(&pppoes_ptype);
1175	dev_add_pack(&pppoed_ptype);
1176	register_netdevice_notifier(&pppoe_notifier);
1177
1178	return 0;
1179
1180out_unregister_pppoe_proto:
1181	proto_unregister(&pppoe_sk_proto);
1182out_unregister_net_ops:
1183	unregister_pernet_device(&pppoe_net_ops);
1184out:
1185	return err;
1186}
1187
1188static void __exit pppoe_exit(void)
1189{
1190	unregister_netdevice_notifier(&pppoe_notifier);
1191	dev_remove_pack(&pppoed_ptype);
1192	dev_remove_pack(&pppoes_ptype);
1193	unregister_pppox_proto(PX_PROTO_OE);
1194	proto_unregister(&pppoe_sk_proto);
1195	unregister_pernet_device(&pppoe_net_ops);
1196}
1197
1198module_init(pppoe_init);
1199module_exit(pppoe_exit);
1200
1201MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
1202MODULE_DESCRIPTION("PPP over Ethernet driver");
1203MODULE_LICENSE("GPL");
1204MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OE);