workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 1311 insertions, 0 deletions

diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
new file mode 100644
index 000000000..4a018acb5
--- /dev/null
+++ b/drivers/net/ppp/pppoe.c
@@ -0,0 +1,1311 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** -*- linux-c -*- ***********************************************************
+ * Linux PPP over Ethernet (PPPoX/PPPoE) Sockets
+ *
+ * PPPoX --- Generic PPP encapsulation socket family
+ * PPPoE --- PPP over Ethernet (RFC 2516)
+ *
+ * Version:	0.7.0
+ *
+ * 070228 :	Fix to allow multiple sessions with same remote MAC and same
+ *		session id by including the local device ifindex in the
+ *		tuple identifying a session. This also ensures packets can't
+ *		be injected into a session from interfaces other than the one
+ *		specified by userspace. Florian Zumbiehl <florz@florz.de>
+ *		(Oh, BTW, this one is YYMMDD, in case you were wondering ...)
+ * 220102 :	Fix module use count on failure in pppoe_create, pppox_sk -acme
+ * 030700 :	Fixed connect logic to allow for disconnect.
+ * 270700 :	Fixed potential SMP problems; we must protect against
+ *		simultaneous invocation of ppp_input
+ *		and ppp_unregister_channel.
+ * 040800 :	Respect reference count mechanisms on net-devices.
+ * 200800 :	fix kfree(skb) in pppoe_rcv (acme)
+ *		Module reference count is decremented in the right spot now,
+ *		guards against sock_put not actually freeing the sk
+ *		in pppoe_release.
+ * 051000 :	Initialization cleanup.
+ * 111100 :	Fix recvmsg.
+ * 050101 :	Fix PADT processing.
+ * 140501 :	Use pppoe_rcv_core to handle all backlog. (Alexey)
+ * 170701 :	Do not lock_sock with rwlock held. (DaveM)
+ *		Ignore discovery frames if user has socket
+ *		locked. (DaveM)
+ *		Ignore return value of dev_queue_xmit in __pppoe_xmit
+ *		or else we may kfree an SKB twice. (DaveM)
+ * 190701 :	When doing copies of skb's in __pppoe_xmit, always delete
+ *		the original skb that was passed in on success, never on
+ *		failure.  Delete the copy of the skb on failure to avoid
+ *		a memory leak.
+ * 081001 :	Misc. cleanup (licence string, non-blocking, prevent
+ *		reference of device on close).
+ * 121301 :	New ppp channels interface; cannot unregister a channel
+ *		from interrupts.  Thus, we mark the socket as a ZOMBIE
+ *		and do the unregistration later.
+ * 081002 :	seq_file support for proc stuff -acme
+ * 111602 :	Merge all 2.4 fixes into 2.5/2.6 tree.  Label 2.5/2.6
+ *		as version 0.7.  Spacing cleanup.
+ * Author:	Michal Ostrowski <mostrows@speakeasy.net>
+ * Contributors:
+ * 		Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *		David S. Miller (davem@redhat.com)
+ *
+ * License:
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/net.h>
+#include <linux/inetdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+#include <linux/if_ether.h>
+#include <linux/if_pppox.h>
+#include <linux/ppp_channel.h>
+#include <linux/ppp_defs.h>
+#include <linux/ppp-ioctl.h>
+#include <linux/notifier.h>
+#include <linux/file.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/sock.h>
+#include <net/gro.h>
+
+#include <linux/uaccess.h>
+
+#define PPPOE_HASH_BITS CONFIG_PPPOE_HASH_BITS
+#define PPPOE_HASH_SIZE (1 << PPPOE_HASH_BITS)
+#define PPPOE_HASH_MASK	(PPPOE_HASH_SIZE - 1)
+
+static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb);
+
+static const struct proto_ops pppoe_ops;
+static const struct ppp_channel_ops pppoe_chan_ops;
+
+/* per-net private data for this module */
+static unsigned int pppoe_net_id __read_mostly;
+struct pppoe_net {
+	/*
+	 * we could use _single_ hash table for all
+	 * nets by injecting net id into the hash but
+	 * it would increase hash chains and add
+	 * a few additional math comparisons messy
+	 * as well, moreover in case of SMP less locking
+	 * controversy here
+	 */
+	struct pppox_sock __rcu *hash_table[PPPOE_HASH_SIZE];
+	spinlock_t hash_lock;
+};
+
+/*
+ * PPPoE could be in the following stages:
+ * 1) Discovery stage (to obtain remote MAC and Session ID)
+ * 2) Session stage (MAC and SID are known)
+ *
+ * Ethernet frames have a special tag for this but
+ * we use simpler approach based on session id
+ */
+static inline bool stage_session(__be16 sid)
+{
+	return sid != 0;
+}
+
+static inline struct pppoe_net *pppoe_pernet(struct net *net)
+{
+	return net_generic(net, pppoe_net_id);
+}
+
+static inline int cmp_2_addr(struct pppoe_addr *a, struct pppoe_addr *b)
+{
+	return a->sid == b->sid && ether_addr_equal(a->remote, b->remote);
+}
+
+static inline int cmp_addr(struct pppoe_addr *a, __be16 sid, char *addr)
+{
+	return a->sid == sid && ether_addr_equal(a->remote, addr);
+}
+
+#if 8 % PPPOE_HASH_BITS
+#error 8 must be a multiple of PPPOE_HASH_BITS
+#endif
+
+static u8 hash_item(__be16 sid, const u8 addr[ETH_ALEN])
+{
+	const u16 *addr16 = (const u16 *)addr;
+	unsigned int i;
+	u16 hash16;
+	u8 hash;
+
+	hash16 = addr16[0] ^ addr16[1] ^ addr16[2] ^ (__force u16)sid;
+	hash = (hash16 >> 8) ^ hash16;
+	for (i = 8; (i >>= 1) >= PPPOE_HASH_BITS;)
+		hash ^= hash >> i;
+
+	return hash & PPPOE_HASH_MASK;
+}
+
+/**********************************************************************
+ *
+ *  Set/get/delete/rehash items  (internal versions)
+ *
+ **********************************************************************/
+static struct pppox_sock *__get_item(struct pppoe_net *pn, __be16 sid,
+				unsigned char *addr, int ifindex)
+{
+	int hash = hash_item(sid, addr);
+	struct pppox_sock *ret;
+
+	ret = rcu_dereference(pn->hash_table[hash]);
+	while (ret) {
+		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
+		    ret->pppoe_ifindex == ifindex)
+			return ret;
+
+		ret = rcu_dereference(ret->next);
+	}
+
+	return NULL;
+}
+
+static int __set_item(struct pppoe_net *pn, struct pppox_sock *po)
+{
+	int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
+	struct pppox_sock *ret, *first;
+
+	first = rcu_dereference_protected(pn->hash_table[hash], lockdep_is_held(&pn->hash_lock));
+	ret = first;
+	while (ret) {
+		if (cmp_2_addr(&ret->pppoe_pa, &po->pppoe_pa) &&
+		    ret->pppoe_ifindex == po->pppoe_ifindex)
+			return -EALREADY;
+
+		ret = rcu_dereference_protected(ret->next, lockdep_is_held(&pn->hash_lock));
+	}
+
+	RCU_INIT_POINTER(po->next, first);
+	rcu_assign_pointer(pn->hash_table[hash], po);
+
+	return 0;
+}
+
+static void __delete_item(struct pppoe_net *pn, __be16 sid,
+					char *addr, int ifindex)
+{
+	int hash = hash_item(sid, addr);
+	struct pppox_sock *ret, __rcu **src;
+
+	ret = rcu_dereference_protected(pn->hash_table[hash], lockdep_is_held(&pn->hash_lock));
+	src = &pn->hash_table[hash];
+
+	while (ret) {
+		if (cmp_addr(&ret->pppoe_pa, sid, addr) &&
+		    ret->pppoe_ifindex == ifindex) {
+			struct pppox_sock *next;
+
+			next = rcu_dereference_protected(ret->next,
+							 lockdep_is_held(&pn->hash_lock));
+			rcu_assign_pointer(*src, next);
+			break;
+		}
+
+		src = &ret->next;
+		ret = rcu_dereference_protected(ret->next, lockdep_is_held(&pn->hash_lock));
+	}
+}
+
+/**********************************************************************
+ *
+ *  Set/get/delete/rehash items
+ *
+ **********************************************************************/
+static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid,
+					unsigned char *addr, int ifindex)
+{
+	struct pppox_sock *po;
+
+	po = __get_item(pn, sid, addr, ifindex);
+	if (po && !refcount_inc_not_zero(&po->sk.sk_refcnt))
+		po = NULL;
+
+	return po;
+}
+
+static inline void delete_item(struct pppoe_net *pn, __be16 sid,
+					char *addr, int ifindex)
+{
+	spin_lock(&pn->hash_lock);
+	__delete_item(pn, sid, addr, ifindex);
+	spin_unlock(&pn->hash_lock);
+}
+
+/***************************************************************************
+ *
+ *  Handler for device events.
+ *  Certain device events require that sockets be unconnected.
+ *
+ **************************************************************************/
+
+static void pppoe_flush_dev(struct net_device *dev)
+{
+	struct pppoe_net *pn;
+	int i;
+
+	pn = pppoe_pernet(dev_net(dev));
+	spin_lock(&pn->hash_lock);
+	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
+		struct pppox_sock *po = rcu_dereference_protected(pn->hash_table[i],
+								  lockdep_is_held(&pn->hash_lock));
+		struct sock *sk;
+
+		while (po) {
+			while (po && po->pppoe_dev != dev) {
+				po = rcu_dereference_protected(po->next,
+							       lockdep_is_held(&pn->hash_lock));
+			}
+
+			if (!po)
+				break;
+
+			sk = &po->sk;
+
+			/* We always grab the socket lock, followed by the
+			 * hash_lock, in that order.  Since we should hold the
+			 * sock lock while doing any unbinding, we need to
+			 * release the lock we're holding.  Hold a reference to
+			 * the sock so it doesn't disappear as we're jumping
+			 * between locks.
+			 */
+
+			sock_hold(sk);
+			spin_unlock(&pn->hash_lock);
+			lock_sock(sk);
+
+			if (po->pppoe_dev == dev &&
+			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
+				pppox_unbind_sock(sk);
+				sk->sk_state_change(sk);
+				po->pppoe_dev = NULL;
+				dev_put(dev);
+			}
+
+			release_sock(sk);
+			sock_put(sk);
+
+			/* Restart the process from the start of the current
+			 * hash chain. We dropped locks so the world may have
+			 * change from underneath us.
+			 */
+
+			BUG_ON(pppoe_pernet(dev_net(dev)) == NULL);
+			spin_lock(&pn->hash_lock);
+			po = rcu_dereference_protected(pn->hash_table[i],
+						       lockdep_is_held(&pn->hash_lock));
+		}
+	}
+	spin_unlock(&pn->hash_lock);
+}
+
+static int pppoe_device_event(struct notifier_block *this,
+			      unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	/* Only look at sockets that are using this specific device. */
+	switch (event) {
+	case NETDEV_CHANGEADDR:
+	case NETDEV_CHANGEMTU:
+		/* A change in mtu or address is a bad thing, requiring
+		 * LCP re-negotiation.
+		 */
+
+	case NETDEV_GOING_DOWN:
+	case NETDEV_DOWN:
+		/* Find every socket on this device and kill it. */
+		pppoe_flush_dev(dev);
+		break;
+
+	default:
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block pppoe_notifier = {
+	.notifier_call = pppoe_device_event,
+};
+
+/************************************************************************
+ *
+ * Do the real work of receiving a PPPoE Session frame.
+ *
+ ***********************************************************************/
+static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
+{
+	struct pppox_sock *po = pppox_sk(sk);
+
+	/* Backlog receive. Semantics of backlog rcv preclude any code from
+	 * executing in lock_sock()/release_sock() bounds; meaning sk->sk_state
+	 * can't change.
+	 */
+
+	if (sk->sk_state & PPPOX_BOUND) {
+		ppp_input(&po->chan, skb);
+	} else {
+		if (sock_queue_rcv_skb(sk, skb))
+			goto abort_kfree;
+	}
+
+	return NET_RX_SUCCESS;
+
+abort_kfree:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+/************************************************************************
+ *
+ * Receive wrapper called in BH context.
+ *
+ ***********************************************************************/
+static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev,
+		     struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct pppoe_hdr *ph;
+	struct pppox_sock *po;
+	struct pppoe_net *pn;
+	int len;
+
+	if (skb->pkt_type == PACKET_OTHERHOST)
+		goto drop;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		goto out;
+
+	if (skb_mac_header_len(skb) < ETH_HLEN)
+		goto drop;
+
+	if (!pskb_may_pull(skb, PPPOE_SES_HLEN))
+		goto drop;
+
+	ph = pppoe_hdr(skb);
+	len = ntohs(ph->length);
+
+	skb_pull_rcsum(skb, sizeof(*ph));
+	if (skb->len < len)
+		goto drop;
+
+	/* skb->data points to the PPP protocol header after skb_pull_rcsum.
+	 * Drop PFC frames.
+	 */
+	if (ppp_skb_is_compressed_proto(skb))
+		goto drop;
+
+	if (!skb_is_gso(skb) && pskb_trim_rcsum(skb, len))
+		goto drop;
+
+	ph = pppoe_hdr(skb);
+	pn = pppoe_pernet(dev_net(dev));
+
+	po = __get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
+	if (!po)
+		goto drop;
+
+	return __sk_receive_skb(&po->sk, skb, 0, 1, false);
+
+drop:
+	kfree_skb(skb);
+out:
+	return NET_RX_DROP;
+}
+
+static void pppoe_unbind_sock_work(struct work_struct *work)
+{
+	struct pppox_sock *po = container_of(work, struct pppox_sock,
+					     proto.pppoe.padt_work);
+	struct sock *sk = &po->sk;
+
+	lock_sock(sk);
+	if (po->pppoe_dev) {
+		dev_put(po->pppoe_dev);
+		po->pppoe_dev = NULL;
+	}
+	pppox_unbind_sock(sk);
+	release_sock(sk);
+	sock_put(sk);
+}
+
+/************************************************************************
+ *
+ * Receive a PPPoE Discovery frame.
+ * This is solely for detection of PADT frames
+ *
+ ***********************************************************************/
+static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
+			  struct packet_type *pt, struct net_device *orig_dev)
+
+{
+	struct pppoe_hdr *ph;
+	struct pppox_sock *po;
+	struct pppoe_net *pn;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		goto out;
+
+	if (skb->pkt_type != PACKET_HOST)
+		goto abort;
+
+	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
+		goto abort;
+
+	ph = pppoe_hdr(skb);
+	if (ph->code != PADT_CODE)
+		goto abort;
+
+	pn = pppoe_pernet(dev_net(dev));
+	po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
+	if (po)
+		if (!schedule_work(&po->proto.pppoe.padt_work))
+			sock_put(&po->sk);
+
+abort:
+	kfree_skb(skb);
+out:
+	return NET_RX_SUCCESS; /* Lies... :-) */
+}
+
+static struct packet_type pppoes_ptype __read_mostly = {
+	.type	= cpu_to_be16(ETH_P_PPP_SES),
+	.func	= pppoe_rcv,
+};
+
+static struct packet_type pppoed_ptype __read_mostly = {
+	.type	= cpu_to_be16(ETH_P_PPP_DISC),
+	.func	= pppoe_disc_rcv,
+};
+
+static struct proto pppoe_sk_proto __read_mostly = {
+	.name	  = "PPPOE",
+	.owner	  = THIS_MODULE,
+	.obj_size = sizeof(struct pppox_sock),
+};
+
+static void pppoe_destruct(struct sock *sk)
+{
+	skb_queue_purge(&sk->sk_receive_queue);
+}
+
+/***********************************************************************
+ *
+ * Initialize a new struct sock.
+ *
+ **********************************************************************/
+static int pppoe_create(struct net *net, struct socket *sock, int kern)
+{
+	struct sock *sk;
+
+	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppoe_sk_proto, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock_init_data(sock, sk);
+	sock_set_flag(sk, SOCK_RCU_FREE);
+
+	sock->state	= SS_UNCONNECTED;
+	sock->ops	= &pppoe_ops;
+
+	sk->sk_backlog_rcv	= pppoe_rcv_core;
+	sk->sk_destruct		= pppoe_destruct;
+	sk->sk_state		= PPPOX_NONE;
+	sk->sk_type		= SOCK_STREAM;
+	sk->sk_family		= PF_PPPOX;
+	sk->sk_protocol		= PX_PROTO_OE;
+
+	INIT_WORK(&pppox_sk(sk)->proto.pppoe.padt_work,
+		  pppoe_unbind_sock_work);
+
+	return 0;
+}
+
+static int pppoe_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct pppox_sock *po;
+	struct pppoe_net *pn;
+	struct net *net = NULL;
+
+	if (!sk)
+		return 0;
+
+	lock_sock(sk);
+	if (sock_flag(sk, SOCK_DEAD)) {
+		release_sock(sk);
+		return -EBADF;
+	}
+
+	po = pppox_sk(sk);
+
+	if (po->pppoe_dev) {
+		dev_put(po->pppoe_dev);
+		po->pppoe_dev = NULL;
+	}
+
+	pppox_unbind_sock(sk);
+
+	/* Signal the death of the socket. */
+	sk->sk_state = PPPOX_DEAD;
+
+	net = sock_net(sk);
+	pn = pppoe_pernet(net);
+
+	/*
+	 * protect "po" from concurrent updates
+	 * on pppoe_flush_dev
+	 */
+	delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote,
+		    po->pppoe_ifindex);
+
+	sock_orphan(sk);
+	sock->sk = NULL;
+
+	release_sock(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+static int pppoe_connect(struct socket *sock, struct sockaddr_unsized *uservaddr,
+			 int sockaddr_len, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sockaddr_pppox *sp = (struct sockaddr_pppox *)uservaddr;
+	struct pppox_sock *po = pppox_sk(sk);
+	struct net_device *dev = NULL;
+	struct pppoe_net *pn;
+	struct net *net = NULL;
+	int error;
+
+	lock_sock(sk);
+
+	error = -EINVAL;
+
+	if (sockaddr_len != sizeof(struct sockaddr_pppox))
+		goto end;
+
+	if (sp->sa_protocol != PX_PROTO_OE)
+		goto end;
+
+	/* Check for already bound sockets */
+	error = -EBUSY;
+	if ((sk->sk_state & PPPOX_CONNECTED) &&
+	     stage_session(sp->sa_addr.pppoe.sid))
+		goto end;
+
+	/* Check for already disconnected sockets, on attempts to disconnect */
+	error = -EALREADY;
+	if ((sk->sk_state & PPPOX_DEAD) &&
+	     !stage_session(sp->sa_addr.pppoe.sid))
+		goto end;
+
+	error = 0;
+
+	/* Delete the old binding */
+	if (stage_session(po->pppoe_pa.sid)) {
+		pppox_unbind_sock(sk);
+		pn = pppoe_pernet(sock_net(sk));
+		delete_item(pn, po->pppoe_pa.sid,
+			    po->pppoe_pa.remote, po->pppoe_ifindex);
+		if (po->pppoe_dev) {
+			dev_put(po->pppoe_dev);
+			po->pppoe_dev = NULL;
+		}
+
+		po->pppoe_ifindex = 0;
+		memset(&po->pppoe_pa, 0, sizeof(po->pppoe_pa));
+		memset(&po->chan, 0, sizeof(po->chan));
+		po->next = NULL;
+		po->num = 0;
+
+		sk->sk_state = PPPOX_NONE;
+	}
+
+	/* Re-bind in session stage only */
+	if (stage_session(sp->sa_addr.pppoe.sid)) {
+		error = -ENODEV;
+		net = sock_net(sk);
+		dev = dev_get_by_name(net, sp->sa_addr.pppoe.dev);
+		if (!dev)
+			goto err_put;
+
+		po->pppoe_dev = dev;
+		po->pppoe_ifindex = dev->ifindex;
+		pn = pppoe_pernet(net);
+		if (!(dev->flags & IFF_UP)) {
+			goto err_put;
+		}
+
+		memcpy(&po->pppoe_pa,
+		       &sp->sa_addr.pppoe,
+		       sizeof(struct pppoe_addr));
+
+		spin_lock(&pn->hash_lock);
+		error = __set_item(pn, po);
+		spin_unlock(&pn->hash_lock);
+		if (error < 0)
+			goto err_put;
+
+		po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
+				   dev->hard_header_len);
+
+		po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
+		po->chan.private = sk;
+		po->chan.ops = &pppoe_chan_ops;
+		po->chan.direct_xmit = true;
+
+		error = ppp_register_net_channel(dev_net(dev), &po->chan);
+		if (error) {
+			delete_item(pn, po->pppoe_pa.sid,
+				    po->pppoe_pa.remote, po->pppoe_ifindex);
+			goto err_put;
+		}
+
+		sk->sk_state = PPPOX_CONNECTED;
+	}
+
+	po->num = sp->sa_addr.pppoe.sid;
+
+end:
+	release_sock(sk);
+	return error;
+err_put:
+	if (po->pppoe_dev) {
+		dev_put(po->pppoe_dev);
+		po->pppoe_dev = NULL;
+	}
+	goto end;
+}
+
+static int pppoe_getname(struct socket *sock, struct sockaddr *uaddr,
+		  int peer)
+{
+	int len = sizeof(struct sockaddr_pppox);
+	struct sockaddr_pppox sp;
+
+	sp.sa_family	= AF_PPPOX;
+	sp.sa_protocol	= PX_PROTO_OE;
+	memcpy(&sp.sa_addr.pppoe, &pppox_sk(sock->sk)->pppoe_pa,
+	       sizeof(struct pppoe_addr));
+
+	memcpy(uaddr, &sp, len);
+
+	return len;
+}
+
+static int pppoe_ioctl(struct socket *sock, unsigned int cmd,
+		unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+	struct pppox_sock *po = pppox_sk(sk);
+	int val;
+	int err;
+
+	switch (cmd) {
+	case PPPIOCGMRU:
+		err = -ENXIO;
+		if (!(sk->sk_state & PPPOX_CONNECTED))
+			break;
+
+		err = -EFAULT;
+		if (put_user(po->pppoe_dev->mtu -
+			     sizeof(struct pppoe_hdr) -
+			     PPP_HDRLEN,
+			     (int __user *)arg))
+			break;
+		err = 0;
+		break;
+
+	case PPPIOCSMRU:
+		err = -ENXIO;
+		if (!(sk->sk_state & PPPOX_CONNECTED))
+			break;
+
+		err = -EFAULT;
+		if (get_user(val, (int __user *)arg))
+			break;
+
+		if (val < (po->pppoe_dev->mtu
+			   - sizeof(struct pppoe_hdr)
+			   - PPP_HDRLEN))
+			err = 0;
+		else
+			err = -EINVAL;
+		break;
+
+	case PPPIOCSFLAGS:
+		err = -EFAULT;
+		if (get_user(val, (int __user *)arg))
+			break;
+		err = 0;
+		break;
+
+	default:
+		err = -ENOTTY;
+	}
+
+	return err;
+}
+
+static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
+			 size_t total_len)
+{
+	struct sk_buff *skb;
+	struct sock *sk = sock->sk;
+	struct pppox_sock *po = pppox_sk(sk);
+	int error;
+	struct pppoe_hdr hdr;
+	struct pppoe_hdr *ph;
+	struct net_device *dev;
+	char *start;
+	int hlen;
+
+	lock_sock(sk);
+	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) {
+		error = -ENOTCONN;
+		goto end;
+	}
+
+	hdr.ver = 1;
+	hdr.type = 1;
+	hdr.code = 0;
+	hdr.sid = po->num;
+
+	dev = po->pppoe_dev;
+
+	error = -EMSGSIZE;
+	if (total_len > (dev->mtu + dev->hard_header_len))
+		goto end;
+
+	hlen = LL_RESERVED_SPACE(dev);
+	skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len +
+			   dev->needed_tailroom, 0, GFP_KERNEL);
+	if (!skb) {
+		error = -ENOMEM;
+		goto end;
+	}
+
+	/* Reserve space for headers. */
+	skb_reserve(skb, hlen);
+	skb_reset_network_header(skb);
+
+	skb->dev = dev;
+
+	skb->priority = READ_ONCE(sk->sk_priority);
+	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
+
+	ph = skb_put(skb, total_len + sizeof(struct pppoe_hdr));
+	start = (char *)ph + sizeof(*ph);
+
+	error = memcpy_from_msg(start, m, total_len);
+	if (error < 0) {
+		kfree_skb(skb);
+		goto end;
+	}
+
+	error = total_len;
+	dev_hard_header(skb, dev, ETH_P_PPP_SES,
+			po->pppoe_pa.remote, NULL, total_len);
+
+	memcpy(ph, &hdr, sizeof(struct pppoe_hdr));
+
+	ph->length = htons(total_len);
+
+	dev_queue_xmit(skb);
+
+end:
+	release_sock(sk);
+	return error;
+}
+
+/************************************************************************
+ *
+ * xmit function for internal use.
+ *
+ ***********************************************************************/
+static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
+{
+	struct pppox_sock *po = pppox_sk(sk);
+	struct net_device *dev = po->pppoe_dev;
+	struct pppoe_hdr *ph;
+	int data_len = skb->len;
+
+	/* The higher-level PPP code (ppp_unregister_channel()) ensures the PPP
+	 * xmit operations conclude prior to an unregistration call.  Thus
+	 * sk->sk_state cannot change, so we don't need to do lock_sock().
+	 * But, we also can't do a lock_sock since that introduces a potential
+	 * deadlock as we'd reverse the lock ordering used when calling
+	 * ppp_unregister_channel().
+	 */
+
+	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
+		goto abort;
+
+	if (!dev)
+		goto abort;
+
+	/* Copy the data if there is no space for the header or if it's
+	 * read-only.
+	 */
+	if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph)))
+		goto abort;
+
+	__skb_push(skb, sizeof(*ph));
+	skb_reset_network_header(skb);
+
+	ph = pppoe_hdr(skb);
+	ph->ver	= 1;
+	ph->type = 1;
+	ph->code = 0;
+	ph->sid	= po->num;
+	ph->length = htons(data_len);
+
+	skb->protocol = cpu_to_be16(ETH_P_PPP_SES);
+	skb->dev = dev;
+
+	dev_hard_header(skb, dev, ETH_P_PPP_SES,
+			po->pppoe_pa.remote, NULL, data_len);
+
+	dev_queue_xmit(skb);
+	return 1;
+
+abort:
+	kfree_skb(skb);
+	return 1;
+}
+
+/************************************************************************
+ *
+ * xmit function called by generic PPP driver
+ * sends PPP frame over PPPoE socket
+ *
+ ***********************************************************************/
+static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
+{
+	struct sock *sk = chan->private;
+	return __pppoe_xmit(sk, skb);
+}
+
+static int pppoe_fill_forward_path(struct net_device_path_ctx *ctx,
+				   struct net_device_path *path,
+				   const struct ppp_channel *chan)
+{
+	struct sock *sk = chan->private;
+	struct pppox_sock *po = pppox_sk(sk);
+	struct net_device *dev = po->pppoe_dev;
+
+	if (sock_flag(sk, SOCK_DEAD) ||
+	    !(sk->sk_state & PPPOX_CONNECTED) || !dev)
+		return -1;
+
+	path->type = DEV_PATH_PPPOE;
+	path->encap.proto = htons(ETH_P_PPP_SES);
+	path->encap.id = be16_to_cpu(po->num);
+	memcpy(path->encap.h_dest, po->pppoe_pa.remote, ETH_ALEN);
+	memcpy(ctx->daddr, po->pppoe_pa.remote, ETH_ALEN);
+	path->dev = ctx->dev;
+	ctx->dev = dev;
+
+	return 0;
+}
+
+static const struct ppp_channel_ops pppoe_chan_ops = {
+	.start_xmit = pppoe_xmit,
+	.fill_forward_path = pppoe_fill_forward_path,
+};
+
+static int pppoe_recvmsg(struct socket *sock, struct msghdr *m,
+			 size_t total_len, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	int error = 0;
+
+	if (sk->sk_state & PPPOX_BOUND)
+		return -EIO;
+
+	skb = skb_recv_datagram(sk, flags, &error);
+	if (!skb)
+		return error;
+
+	total_len = min_t(size_t, total_len, skb->len);
+	error = skb_copy_datagram_msg(skb, 0, m, total_len);
+	if (error == 0) {
+		consume_skb(skb);
+		return total_len;
+	}
+
+	kfree_skb(skb);
+	return error;
+}
+
+#ifdef CONFIG_PROC_FS
+static int pppoe_seq_show(struct seq_file *seq, void *v)
+{
+	struct pppox_sock *po;
+	char *dev_name;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(seq, "Id       Address              Device\n");
+		goto out;
+	}
+
+	po = v;
+	dev_name = po->pppoe_pa.dev;
+
+	seq_printf(seq, "%08X %pM %8s\n",
+		po->pppoe_pa.sid, po->pppoe_pa.remote, dev_name);
+out:
+	return 0;
+}
+
+static inline struct pppox_sock *pppoe_get_idx(struct pppoe_net *pn, loff_t pos)
+{
+	struct pppox_sock *po;
+	int i;
+
+	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
+		po = rcu_dereference(pn->hash_table[i]);
+		while (po) {
+			if (!pos--)
+				goto out;
+			po = rcu_dereference(po->next);
+		}
+	}
+
+out:
+	return po;
+}
+
+static void *pppoe_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
+	loff_t l = *pos;
+
+	rcu_read_lock();
+	return l ? pppoe_get_idx(pn, --l) : SEQ_START_TOKEN;
+}
+
+static void *pppoe_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct pppoe_net *pn = pppoe_pernet(seq_file_net(seq));
+	struct pppox_sock *po, *next;
+
+	++*pos;
+	if (v == SEQ_START_TOKEN) {
+		po = pppoe_get_idx(pn, 0);
+		goto out;
+	}
+	po = v;
+	next = rcu_dereference(po->next);
+	if (next)
+		po = next;
+	else {
+		int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote);
+
+		po = NULL;
+		while (++hash < PPPOE_HASH_SIZE) {
+			po = rcu_dereference(pn->hash_table[hash]);
+			if (po)
+				break;
+		}
+	}
+
+out:
+	return po;
+}
+
+static void pppoe_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static const struct seq_operations pppoe_seq_ops = {
+	.start		= pppoe_seq_start,
+	.next		= pppoe_seq_next,
+	.stop		= pppoe_seq_stop,
+	.show		= pppoe_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
+
+static const struct proto_ops pppoe_ops = {
+	.family		= AF_PPPOX,
+	.owner		= THIS_MODULE,
+	.release	= pppoe_release,
+	.bind		= sock_no_bind,
+	.connect	= pppoe_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= pppoe_getname,
+	.poll		= datagram_poll,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.sendmsg	= pppoe_sendmsg,
+	.recvmsg	= pppoe_recvmsg,
+	.mmap		= sock_no_mmap,
+	.ioctl		= pppox_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= pppox_compat_ioctl,
+#endif
+};
+
+static const struct pppox_proto pppoe_proto = {
+	.create	= pppoe_create,
+	.ioctl	= pppoe_ioctl,
+	.owner	= THIS_MODULE,
+};
+
+static __net_init int pppoe_init_net(struct net *net)
+{
+	struct pppoe_net *pn = pppoe_pernet(net);
+	struct proc_dir_entry *pde;
+
+	spin_lock_init(&pn->hash_lock);
+
+	pde = proc_create_net("pppoe", 0444, net->proc_net,
+			&pppoe_seq_ops, sizeof(struct seq_net_private));
+#ifdef CONFIG_PROC_FS
+	if (!pde)
+		return -ENOMEM;
+#endif
+
+	return 0;
+}
+
+static __net_exit void pppoe_exit_net(struct net *net)
+{
+	remove_proc_entry("pppoe", net->proc_net);
+}
+
+static struct pernet_operations pppoe_net_ops = {
+	.init = pppoe_init_net,
+	.exit = pppoe_exit_net,
+	.id   = &pppoe_net_id,
+	.size = sizeof(struct pppoe_net),
+};
+
+static u16
+compare_pppoe_header(const struct pppoe_hdr *phdr,
+		     const struct pppoe_hdr *phdr2)
+{
+	__be16 proto = *(const __be16 *)(phdr + 1);
+	__be16 proto2 = *(const __be16 *)(phdr2 + 1);
+
+	return (__force u16)((phdr->sid ^ phdr2->sid) | (proto ^ proto2));
+}
+
+static __be16 pppoe_hdr_proto(const struct pppoe_hdr *phdr)
+{
+	__be16 proto = *(const __be16 *)(phdr + 1);
+
+	switch (proto) {
+	case cpu_to_be16(PPP_IP):
+		return cpu_to_be16(ETH_P_IP);
+#if IS_ENABLED(CONFIG_IPV6)
+	case cpu_to_be16(PPP_IPV6):
+		return cpu_to_be16(ETH_P_IPV6);
+#endif
+	default:
+		return 0;
+	}
+}
+
+static struct sk_buff *pppoe_gro_receive(struct list_head *head,
+					 struct sk_buff *skb)
+{
+	const struct packet_offload *ptype;
+	unsigned int hlen, off_pppoe;
+	const struct pppoe_hdr *phdr;
+	struct sk_buff *pp = NULL;
+	struct sk_buff *p;
+	int flush = 1;
+	__be16 type;
+
+	off_pppoe = skb_gro_offset(skb);
+	hlen = off_pppoe + PPPOE_SES_HLEN;
+	phdr = skb_gro_header(skb, hlen, off_pppoe);
+	if (unlikely(!phdr))
+		goto out;
+
+	/* filter for session packets (type:1, ver:1, code:0) */
+	if (*(const __be16 *)phdr != cpu_to_be16(0x1100))
+		goto out;
+
+	/* ignore packets with padding or invalid length */
+	if (skb_gro_len(skb) != be16_to_cpu(phdr->length) + sizeof(*phdr))
+		goto out;
+
+	type = pppoe_hdr_proto(phdr);
+	ptype = gro_find_receive_by_type(type);
+	if (!ptype)
+		goto out;
+
+	flush = 0;
+
+	list_for_each_entry(p, head, list) {
+		const struct pppoe_hdr *phdr2;
+
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		phdr2 = (const struct pppoe_hdr *)(p->data + off_pppoe);
+		if (compare_pppoe_header(phdr, phdr2))
+			NAPI_GRO_CB(p)->same_flow = 0;
+	}
+
+	skb_gro_pull(skb, PPPOE_SES_HLEN);
+	skb_gro_postpull_rcsum(skb, phdr, PPPOE_SES_HLEN);
+
+	pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
+					    ipv6_gro_receive, inet_gro_receive,
+					    head, skb);
+
+out:
+	skb_gro_flush_final(skb, pp, flush);
+
+	return pp;
+}
+
+static int pppoe_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	struct pppoe_hdr *phdr = (struct pppoe_hdr *)(skb->data + nhoff);
+	__be16 type = pppoe_hdr_proto(phdr);
+	struct packet_offload *ptype;
+	unsigned int len;
+
+	ptype = gro_find_complete_by_type(type);
+	if (!ptype)
+		return -ENOENT;
+
+	len = skb->len - (nhoff + sizeof(*phdr));
+	len = min(len, 0xFFFFU);
+	phdr->length = cpu_to_be16(len);
+
+	return INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
+				  ipv6_gro_complete, inet_gro_complete,
+				  skb, nhoff + PPPOE_SES_HLEN);
+}
+
+static struct sk_buff *pppoe_gso_segment(struct sk_buff *skb,
+					 netdev_features_t features)
+{
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	struct packet_offload *ptype;
+	struct pppoe_hdr *phdr;
+	__be16 orig_type, type;
+	int len, nhoff;
+
+	skb_reset_network_header(skb);
+	nhoff = skb_network_header(skb) - skb_mac_header(skb);
+
+	if (unlikely(!pskb_may_pull(skb, PPPOE_SES_HLEN)))
+		goto out;
+
+	phdr = (struct pppoe_hdr *)skb_network_header(skb);
+	type = pppoe_hdr_proto(phdr);
+	ptype = gro_find_complete_by_type(type);
+	if (!ptype)
+		goto out;
+
+	orig_type = skb->protocol;
+	__skb_pull(skb, PPPOE_SES_HLEN);
+	features &= ~NETIF_F_GSO_SOFTWARE;
+	segs = ptype->callbacks.gso_segment(skb, features);
+	if (IS_ERR_OR_NULL(segs))
+		goto out;
+
+	skb = segs;
+	do {
+		phdr = (struct pppoe_hdr *)(skb_mac_header(skb) + nhoff);
+		len = skb->len - (nhoff + sizeof(*phdr));
+		phdr->length = cpu_to_be16(len);
+		skb->network_header = (u8 *)phdr - skb->head;
+		skb->protocol = orig_type;
+		skb_reset_mac_len(skb);
+	} while ((skb = skb->next));
+
+out:
+	return segs;
+}
+
+static struct packet_offload pppoe_packet_offload __read_mostly = {
+	.type = cpu_to_be16(ETH_P_PPP_SES),
+	.priority = 20,
+	.callbacks = {
+		.gro_receive = pppoe_gro_receive,
+		.gro_complete = pppoe_gro_complete,
+		.gso_segment = pppoe_gso_segment,
+	},
+};
+
+static int __init pppoe_init(void)
+{
+	int err;
+
+	err = register_pernet_device(&pppoe_net_ops);
+	if (err)
+		goto out;
+
+	err = proto_register(&pppoe_sk_proto, 0);
+	if (err)
+		goto out_unregister_net_ops;
+
+	err = register_pppox_proto(PX_PROTO_OE, &pppoe_proto);
+	if (err)
+		goto out_unregister_pppoe_proto;
+
+	if (IS_ENABLED(CONFIG_INET))
+		dev_add_offload(&pppoe_packet_offload);
+	dev_add_pack(&pppoes_ptype);
+	dev_add_pack(&pppoed_ptype);
+	register_netdevice_notifier(&pppoe_notifier);
+
+	return 0;
+
+out_unregister_pppoe_proto:
+	proto_unregister(&pppoe_sk_proto);
+out_unregister_net_ops:
+	unregister_pernet_device(&pppoe_net_ops);
+out:
+	return err;
+}
+
+static void __exit pppoe_exit(void)
+{
+	unregister_netdevice_notifier(&pppoe_notifier);
+	dev_remove_pack(&pppoed_ptype);
+	dev_remove_pack(&pppoes_ptype);
+	if (IS_ENABLED(CONFIG_INET))
+		dev_remove_offload(&pppoe_packet_offload);
+	unregister_pppox_proto(PX_PROTO_OE);
+	proto_unregister(&pppoe_sk_proto);
+	unregister_pernet_device(&pppoe_net_ops);
+}
+
+module_init(pppoe_init);
+module_exit(pppoe_exit);
+
+MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
+MODULE_DESCRIPTION("PPP over Ethernet driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NET_PF_PROTO(PF_PPPOX, PX_PROTO_OE);