Initial import

1 files changed, 4176 insertions, 0 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
new file mode 100644
index 000000000..fe1610dde
--- /dev/null
+++ b/net/packet/af_packet.c
@@ -0,0 +1,4176 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		PACKET - implements raw packet sockets.
+ *
+ * Authors:	Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *		Alan Cox, <gw4pts@gw4pts.ampr.org>
+ *
+ * Fixes:
+ *		Alan Cox	:	verify_area() now used correctly
+ *		Alan Cox	:	new skbuff lists, look ma no backlogs!
+ *		Alan Cox	:	tidied skbuff lists.
+ *		Alan Cox	:	Now uses generic datagram routines I
+ *					added. Also fixed the peek/read crash
+ *					from all old Linux datagram code.
+ *		Alan Cox	:	Uses the improved datagram code.
+ *		Alan Cox	:	Added NULL's for socket options.
+ *		Alan Cox	:	Re-commented the code.
+ *		Alan Cox	:	Use new kernel side addressing
+ *		Rob Janssen	:	Correct MTU usage.
+ *		Dave Platt	:	Counter leaks caused by incorrect
+ *					interrupt locking and some slightly
+ *					dubious gcc output. Can you read
+ *					compiler: it said _VOLATILE_
+ *	Richard Kooijman	:	Timestamp fixes.
+ *		Alan Cox	:	New buffers. Use sk->mac.raw.
+ *		Alan Cox	:	sendmsg/recvmsg support.
+ *		Alan Cox	:	Protocol setting support
+ *	Alexey Kuznetsov	:	Untied from IPv4 stack.
+ *	Cyrus Durgin		:	Fixed kerneld for kmod.
+ *	Michal Ostrowski        :       Module initialization cleanup.
+ *         Ulises Alonso        :       Frame number limit removal and
+ *                                      packet_set_ring memory leak.
+ *		Eric Biederman	:	Allow for > 8 byte hardware addresses.
+ *					The convention is that longer addresses
+ *					will simply extend the hardware address
+ *					byte arrays at the end of sockaddr_ll
+ *					and packet_mreq.
+ *		Johann Baudy	:	Added TX RING.
+ *		Chetan Loke	:	Implemented TPACKET_V3 block abstraction
+ *					layer.
+ *					Copyright (C) 2011, <lokec@ccs.neu.edu>
+ *
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/capability.h>
+#include <linux/fcntl.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_packet.h>
+#include <linux/wireless.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <net/net_namespace.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <asm/uaccess.h>
+#include <asm/ioctls.h>
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+#include <asm/io.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/poll.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/if_vlan.h>
+#include <linux/virtio_net.h>
+#include <linux/errqueue.h>
+#include <linux/net_tstamp.h>
+#include <linux/percpu.h>
+#ifdef CONFIG_INET
+#include <net/inet_common.h>
+#endif
+
+#include "internal.h"
+
+/*
+   Assumptions:
+   - if device has no dev->hard_header routine, it adds and removes ll header
+     inside itself. In this case ll header is invisible outside of device,
+     but higher levels still should reserve dev->hard_header_len.
+     Some devices are enough clever to reallocate skb, when header
+     will not fit to reserved space (tunnel), another ones are silly
+     (PPP).
+   - packet socket receives packets with pulled ll header,
+     so that SOCK_RAW should push it back.
+
+On receive:
+-----------
+
+Incoming, dev->hard_header!=NULL
+   mac_header -> ll header
+   data       -> data
+
+Outgoing, dev->hard_header!=NULL
+   mac_header -> ll header
+   data       -> ll header
+
+Incoming, dev->hard_header==NULL
+   mac_header -> UNKNOWN position. It is very likely, that it points to ll
+		 header.  PPP makes it, that is wrong, because introduce
+		 assymetry between rx and tx paths.
+   data       -> data
+
+Outgoing, dev->hard_header==NULL
+   mac_header -> data. ll header is still not built!
+   data       -> data
+
+Resume
+  If dev->hard_header==NULL we are unlikely to restore sensible ll header.
+
+
+On transmit:
+------------
+
+dev->hard_header != NULL
+   mac_header -> ll header
+   data       -> ll header
+
+dev->hard_header == NULL (ll header is added by device, we cannot control it)
+   mac_header -> data
+   data       -> data
+
+   We should set nh.raw on output to correct posistion,
+   packet classifier depends on it.
+ */
+
+/* Private packet socket structures. */
+
+/* identical to struct packet_mreq except it has
+ * a longer address field.
+ */
+struct packet_mreq_max {
+	int		mr_ifindex;
+	unsigned short	mr_type;
+	unsigned short	mr_alen;
+	unsigned char	mr_address[MAX_ADDR_LEN];
+};
+
+union tpacket_uhdr {
+	struct tpacket_hdr  *h1;
+	struct tpacket2_hdr *h2;
+	struct tpacket3_hdr *h3;
+	void *raw;
+};
+
+static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
+		int closing, int tx_ring);
+
+#define V3_ALIGNMENT	(8)
+
+#define BLK_HDR_LEN	(ALIGN(sizeof(struct tpacket_block_desc), V3_ALIGNMENT))
+
+#define BLK_PLUS_PRIV(sz_of_priv) \
+	(BLK_HDR_LEN + ALIGN((sz_of_priv), V3_ALIGNMENT))
+
+#define PGV_FROM_VMALLOC 1
+
+#define BLOCK_STATUS(x)	((x)->hdr.bh1.block_status)
+#define BLOCK_NUM_PKTS(x)	((x)->hdr.bh1.num_pkts)
+#define BLOCK_O2FP(x)		((x)->hdr.bh1.offset_to_first_pkt)
+#define BLOCK_LEN(x)		((x)->hdr.bh1.blk_len)
+#define BLOCK_SNUM(x)		((x)->hdr.bh1.seq_num)
+#define BLOCK_O2PRIV(x)	((x)->offset_to_priv)
+#define BLOCK_PRIV(x)		((void *)((char *)(x) + BLOCK_O2PRIV(x)))
+
+struct packet_sock;
+static int tpacket_snd(struct packet_sock *po, struct msghdr *msg);
+static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+		       struct packet_type *pt, struct net_device *orig_dev);
+
+static void *packet_previous_frame(struct packet_sock *po,
+		struct packet_ring_buffer *rb,
+		int status);
+static void packet_increment_head(struct packet_ring_buffer *buff);
+static int prb_curr_blk_in_use(struct tpacket_kbdq_core *,
+			struct tpacket_block_desc *);
+static void *prb_dispatch_next_block(struct tpacket_kbdq_core *,
+			struct packet_sock *);
+static void prb_retire_current_block(struct tpacket_kbdq_core *,
+		struct packet_sock *, unsigned int status);
+static int prb_queue_frozen(struct tpacket_kbdq_core *);
+static void prb_open_block(struct tpacket_kbdq_core *,
+		struct tpacket_block_desc *);
+static void prb_retire_rx_blk_timer_expired(unsigned long);
+static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *);
+static void prb_init_blk_timer(struct packet_sock *,
+		struct tpacket_kbdq_core *,
+		void (*func) (unsigned long));
+static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *);
+static void prb_clear_rxhash(struct tpacket_kbdq_core *,
+		struct tpacket3_hdr *);
+static void prb_fill_vlan_info(struct tpacket_kbdq_core *,
+		struct tpacket3_hdr *);
+static void packet_flush_mclist(struct sock *sk);
+
+struct packet_skb_cb {
+	union {
+		struct sockaddr_pkt pkt;
+		union {
+			/* Trick: alias skb original length with
+			 * ll.sll_family and ll.protocol in order
+			 * to save room.
+			 */
+			unsigned int origlen;
+			struct sockaddr_ll ll;
+		};
+	} sa;
+};
+
+#define PACKET_SKB_CB(__skb)	((struct packet_skb_cb *)((__skb)->cb))
+
+#define GET_PBDQC_FROM_RB(x)	((struct tpacket_kbdq_core *)(&(x)->prb_bdqc))
+#define GET_PBLOCK_DESC(x, bid)	\
+	((struct tpacket_block_desc *)((x)->pkbdq[(bid)].buffer))
+#define GET_CURR_PBLOCK_DESC_FROM_CORE(x)	\
+	((struct tpacket_block_desc *)((x)->pkbdq[(x)->kactive_blk_num].buffer))
+#define GET_NEXT_PRB_BLK_NUM(x) \
+	(((x)->kactive_blk_num < ((x)->knum_blocks-1)) ? \
+	((x)->kactive_blk_num+1) : 0)
+
+static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
+static void __fanout_link(struct sock *sk, struct packet_sock *po);
+
+static int packet_direct_xmit(struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+	netdev_features_t features;
+	struct netdev_queue *txq;
+	int ret = NETDEV_TX_BUSY;
+
+	if (unlikely(!netif_running(dev) ||
+		     !netif_carrier_ok(dev)))
+		goto drop;
+
+	features = netif_skb_features(skb);
+	if (skb_needs_linearize(skb, features) &&
+	    __skb_linearize(skb))
+		goto drop;
+
+	txq = skb_get_tx_queue(dev, skb);
+
+	local_bh_disable();
+
+	HARD_TX_LOCK(dev, txq, smp_processor_id());
+	if (!netif_xmit_frozen_or_drv_stopped(txq))
+		ret = netdev_start_xmit(skb, dev, txq, false);
+	HARD_TX_UNLOCK(dev, txq);
+
+	local_bh_enable();
+
+	if (!dev_xmit_complete(ret))
+		kfree_skb(skb);
+
+	return ret;
+drop:
+	atomic_long_inc(&dev->tx_dropped);
+	kfree_skb(skb);
+	return NET_XMIT_DROP;
+}
+
+static struct net_device *packet_cached_dev_get(struct packet_sock *po)
+{
+	struct net_device *dev;
+
+	rcu_read_lock();
+	dev = rcu_dereference(po->cached_dev);
+	if (likely(dev))
+		dev_hold(dev);
+	rcu_read_unlock();
+
+	return dev;
+}
+
+static void packet_cached_dev_assign(struct packet_sock *po,
+				     struct net_device *dev)
+{
+	rcu_assign_pointer(po->cached_dev, dev);
+}
+
+static void packet_cached_dev_reset(struct packet_sock *po)
+{
+	RCU_INIT_POINTER(po->cached_dev, NULL);
+}
+
+static bool packet_use_direct_xmit(const struct packet_sock *po)
+{
+	return po->xmit == packet_direct_xmit;
+}
+
+static u16 __packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb)
+{
+	return (u16) raw_smp_processor_id() % dev->real_num_tx_queues;
+}
+
+static void packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	u16 queue_index;
+
+	if (ops->ndo_select_queue) {
+		queue_index = ops->ndo_select_queue(dev, skb, NULL,
+						    __packet_pick_tx_queue);
+		queue_index = netdev_cap_txqueue(dev, queue_index);
+	} else {
+		queue_index = __packet_pick_tx_queue(dev, skb);
+	}
+
+	skb_set_queue_mapping(skb, queue_index);
+}
+
+/* register_prot_hook must be invoked with the po->bind_lock held,
+ * or from a context in which asynchronous accesses to the packet
+ * socket is not possible (packet_create()).
+ */
+static void register_prot_hook(struct sock *sk)
+{
+	struct packet_sock *po = pkt_sk(sk);
+
+	if (!po->running) {
+		if (po->fanout)
+			__fanout_link(sk, po);
+		else
+			dev_add_pack(&po->prot_hook);
+
+		sock_hold(sk);
+		po->running = 1;
+	}
+}
+
+/* {,__}unregister_prot_hook() must be invoked with the po->bind_lock
+ * held.   If the sync parameter is true, we will temporarily drop
+ * the po->bind_lock and do a synchronize_net to make sure no
+ * asynchronous packet processing paths still refer to the elements
+ * of po->prot_hook.  If the sync parameter is false, it is the
+ * callers responsibility to take care of this.
+ */
+static void __unregister_prot_hook(struct sock *sk, bool sync)
+{
+	struct packet_sock *po = pkt_sk(sk);
+
+	po->running = 0;
+
+	if (po->fanout)
+		__fanout_unlink(sk, po);
+	else
+		__dev_remove_pack(&po->prot_hook);
+
+	__sock_put(sk);
+
+	if (sync) {
+		spin_unlock(&po->bind_lock);
+		synchronize_net();
+		spin_lock(&po->bind_lock);
+	}
+}
+
+static void unregister_prot_hook(struct sock *sk, bool sync)
+{
+	struct packet_sock *po = pkt_sk(sk);
+
+	if (po->running)
+		__unregister_prot_hook(sk, sync);
+}
+
+static inline struct page * __pure pgv_to_page(void *addr)
+{
+	if (is_vmalloc_addr(addr))
+		return vmalloc_to_page(addr);
+	return virt_to_page(addr);
+}
+
+static void __packet_set_status(struct packet_sock *po, void *frame, int status)
+{
+	union tpacket_uhdr h;
+
+	h.raw = frame;
+	switch (po->tp_version) {
+	case TPACKET_V1:
+		h.h1->tp_status = status;
+		flush_dcache_page(pgv_to_page(&h.h1->tp_status));
+		break;
+	case TPACKET_V2:
+		h.h2->tp_status = status;
+		flush_dcache_page(pgv_to_page(&h.h2->tp_status));
+		break;
+	case TPACKET_V3:
+	default:
+		WARN(1, "TPACKET version not supported.\n");
+		BUG();
+	}
+
+	smp_wmb();
+}
+
+static int __packet_get_status(struct packet_sock *po, void *frame)
+{
+	union tpacket_uhdr h;
+
+	smp_rmb();
+
+	h.raw = frame;
+	switch (po->tp_version) {
+	case TPACKET_V1:
+		flush_dcache_page(pgv_to_page(&h.h1->tp_status));
+		return h.h1->tp_status;
+	case TPACKET_V2:
+		flush_dcache_page(pgv_to_page(&h.h2->tp_status));
+		return h.h2->tp_status;
+	case TPACKET_V3:
+	default:
+		WARN(1, "TPACKET version not supported.\n");
+		BUG();
+		return 0;
+	}
+}
+
+static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec *ts,
+				   unsigned int flags)
+{
+	struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
+
+	if (shhwtstamps &&
+	    (flags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
+	    ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts))
+		return TP_STATUS_TS_RAW_HARDWARE;
+
+	if (ktime_to_timespec_cond(skb->tstamp, ts))
+		return TP_STATUS_TS_SOFTWARE;
+
+	return 0;
+}
+
+static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame,
+				    struct sk_buff *skb)
+{
+	union tpacket_uhdr h;
+	struct timespec ts;
+	__u32 ts_status;
+
+	if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
+		return 0;
+
+	h.raw = frame;
+	switch (po->tp_version) {
+	case TPACKET_V1:
+		h.h1->tp_sec = ts.tv_sec;
+		h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
+		break;
+	case TPACKET_V2:
+		h.h2->tp_sec = ts.tv_sec;
+		h.h2->tp_nsec = ts.tv_nsec;
+		break;
+	case TPACKET_V3:
+	default:
+		WARN(1, "TPACKET version not supported.\n");
+		BUG();
+	}
+
+	/* one flush is safe, as both fields always lie on the same cacheline */
+	flush_dcache_page(pgv_to_page(&h.h1->tp_sec));
+	smp_wmb();
+
+	return ts_status;
+}
+
+static void *packet_lookup_frame(struct packet_sock *po,
+		struct packet_ring_buffer *rb,
+		unsigned int position,
+		int status)
+{
+	unsigned int pg_vec_pos, frame_offset;
+	union tpacket_uhdr h;
+
+	pg_vec_pos = position / rb->frames_per_block;
+	frame_offset = position % rb->frames_per_block;
+
+	h.raw = rb->pg_vec[pg_vec_pos].buffer +
+		(frame_offset * rb->frame_size);
+
+	if (status != __packet_get_status(po, h.raw))
+		return NULL;
+
+	return h.raw;
+}
+
+static void *packet_current_frame(struct packet_sock *po,
+		struct packet_ring_buffer *rb,
+		int status)
+{
+	return packet_lookup_frame(po, rb, rb->head, status);
+}
+
+static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc)
+{
+	del_timer_sync(&pkc->retire_blk_timer);
+}
+
+static void prb_shutdown_retire_blk_timer(struct packet_sock *po,
+		int tx_ring,
+		struct sk_buff_head *rb_queue)
+{
+	struct tpacket_kbdq_core *pkc;
+
+	pkc = tx_ring ? GET_PBDQC_FROM_RB(&po->tx_ring) :
+			GET_PBDQC_FROM_RB(&po->rx_ring);
+
+	spin_lock_bh(&rb_queue->lock);
+	pkc->delete_blk_timer = 1;
+	spin_unlock_bh(&rb_queue->lock);
+
+	prb_del_retire_blk_timer(pkc);
+}
+
+static void prb_init_blk_timer(struct packet_sock *po,
+		struct tpacket_kbdq_core *pkc,
+		void (*func) (unsigned long))
+{
+	init_timer(&pkc->retire_blk_timer);
+	pkc->retire_blk_timer.data = (long)po;
+	pkc->retire_blk_timer.function = func;
+	pkc->retire_blk_timer.expires = jiffies;
+}
+
+static void prb_setup_retire_blk_timer(struct packet_sock *po, int tx_ring)
+{
+	struct tpacket_kbdq_core *pkc;
+
+	if (tx_ring)
+		BUG();
+
+	pkc = tx_ring ? GET_PBDQC_FROM_RB(&po->tx_ring) :
+			GET_PBDQC_FROM_RB(&po->rx_ring);
+	prb_init_blk_timer(po, pkc, prb_retire_rx_blk_timer_expired);
+}
+
+static int prb_calc_retire_blk_tmo(struct packet_sock *po,
+				int blk_size_in_bytes)
+{
+	struct net_device *dev;
+	unsigned int mbits = 0, msec = 0, div = 0, tmo = 0;
+	struct ethtool_cmd ecmd;
+	int err;
+	u32 speed;
+
+	rtnl_lock();
+	dev = __dev_get_by_index(sock_net(&po->sk), po->ifindex);
+	if (unlikely(!dev)) {
+		rtnl_unlock();
+		return DEFAULT_PRB_RETIRE_TOV;
+	}
+	err = __ethtool_get_settings(dev, &ecmd);
+	speed = ethtool_cmd_speed(&ecmd);
+	rtnl_unlock();
+	if (!err) {
+		/*
+		 * If the link speed is so slow you don't really
+		 * need to worry about perf anyways
+		 */
+		if (speed < SPEED_1000 || speed == SPEED_UNKNOWN) {
+			return DEFAULT_PRB_RETIRE_TOV;
+		} else {
+			msec = 1;
+			div = speed / 1000;
+		}
+	}
+
+	mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
+
+	if (div)
+		mbits /= div;
+
+	tmo = mbits * msec;
+
+	if (div)
+		return tmo+1;
+	return tmo;
+}
+
+static void prb_init_ft_ops(struct tpacket_kbdq_core *p1,
+			union tpacket_req_u *req_u)
+{
+	p1->feature_req_word = req_u->req3.tp_feature_req_word;
+}
+
+static void init_prb_bdqc(struct packet_sock *po,
+			struct packet_ring_buffer *rb,
+			struct pgv *pg_vec,
+			union tpacket_req_u *req_u, int tx_ring)
+{
+	struct tpacket_kbdq_core *p1 = GET_PBDQC_FROM_RB(rb);
+	struct tpacket_block_desc *pbd;
+
+	memset(p1, 0x0, sizeof(*p1));
+
+	p1->knxt_seq_num = 1;
+	p1->pkbdq = pg_vec;
+	pbd = (struct tpacket_block_desc *)pg_vec[0].buffer;
+	p1->pkblk_start	= pg_vec[0].buffer;
+	p1->kblk_size = req_u->req3.tp_block_size;
+	p1->knum_blocks	= req_u->req3.tp_block_nr;
+	p1->hdrlen = po->tp_hdrlen;
+	p1->version = po->tp_version;
+	p1->last_kactive_blk_num = 0;
+	po->stats.stats3.tp_freeze_q_cnt = 0;
+	if (req_u->req3.tp_retire_blk_tov)
+		p1->retire_blk_tov = req_u->req3.tp_retire_blk_tov;
+	else
+		p1->retire_blk_tov = prb_calc_retire_blk_tmo(po,
+						req_u->req3.tp_block_size);
+	p1->tov_in_jiffies = msecs_to_jiffies(p1->retire_blk_tov);
+	p1->blk_sizeof_priv = req_u->req3.tp_sizeof_priv;
+
+	p1->max_frame_len = p1->kblk_size - BLK_PLUS_PRIV(p1->blk_sizeof_priv);
+	prb_init_ft_ops(p1, req_u);
+	prb_setup_retire_blk_timer(po, tx_ring);
+	prb_open_block(p1, pbd);
+}
+
+/*  Do NOT update the last_blk_num first.
+ *  Assumes sk_buff_head lock is held.
+ */
+static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc)
+{
+	mod_timer(&pkc->retire_blk_timer,
+			jiffies + pkc->tov_in_jiffies);
+	pkc->last_kactive_blk_num = pkc->kactive_blk_num;
+}
+
+/*
+ * Timer logic:
+ * 1) We refresh the timer only when we open a block.
+ *    By doing this we don't waste cycles refreshing the timer
+ *	  on packet-by-packet basis.
+ *
+ * With a 1MB block-size, on a 1Gbps line, it will take
+ * i) ~8 ms to fill a block + ii) memcpy etc.
+ * In this cut we are not accounting for the memcpy time.
+ *
+ * So, if the user sets the 'tmo' to 10ms then the timer
+ * will never fire while the block is still getting filled
+ * (which is what we want). However, the user could choose
+ * to close a block early and that's fine.
+ *
+ * But when the timer does fire, we check whether or not to refresh it.
+ * Since the tmo granularity is in msecs, it is not too expensive
+ * to refresh the timer, lets say every '8' msecs.
+ * Either the user can set the 'tmo' or we can derive it based on
+ * a) line-speed and b) block-size.
+ * prb_calc_retire_blk_tmo() calculates the tmo.
+ *
+ */
+static void prb_retire_rx_blk_timer_expired(unsigned long data)
+{
+	struct packet_sock *po = (struct packet_sock *)data;
+	struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
+	unsigned int frozen;
+	struct tpacket_block_desc *pbd;
+
+	spin_lock(&po->sk.sk_receive_queue.lock);
+
+	frozen = prb_queue_frozen(pkc);
+	pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
+
+	if (unlikely(pkc->delete_blk_timer))
+		goto out;
+
+	/* We only need to plug the race when the block is partially filled.
+	 * tpacket_rcv:
+	 *		lock(); increment BLOCK_NUM_PKTS; unlock()
+	 *		copy_bits() is in progress ...
+	 *		timer fires on other cpu:
+	 *		we can't retire the current block because copy_bits
+	 *		is in progress.
+	 *
+	 */
+	if (BLOCK_NUM_PKTS(pbd)) {
+		while (atomic_read(&pkc->blk_fill_in_prog)) {
+			/* Waiting for skb_copy_bits to finish... */
+			cpu_relax();
+		}
+	}
+
+	if (pkc->last_kactive_blk_num == pkc->kactive_blk_num) {
+		if (!frozen) {
+			if (!BLOCK_NUM_PKTS(pbd)) {
+				/* An empty block. Just refresh the timer. */
+				goto refresh_timer;
+			}
+			prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO);
+			if (!prb_dispatch_next_block(pkc, po))
+				goto refresh_timer;
+			else
+				goto out;
+		} else {
+			/* Case 1. Queue was frozen because user-space was
+			 *	   lagging behind.
+			 */
+			if (prb_curr_blk_in_use(pkc, pbd)) {
+				/*
+				 * Ok, user-space is still behind.
+				 * So just refresh the timer.
+				 */
+				goto refresh_timer;
+			} else {
+			       /* Case 2. queue was frozen,user-space caught up,
+				* now the link went idle && the timer fired.
+				* We don't have a block to close.So we open this
+				* block and restart the timer.
+				* opening a block thaws the queue,restarts timer
+				* Thawing/timer-refresh is a side effect.
+				*/
+				prb_open_block(pkc, pbd);
+				goto out;
+			}
+		}
+	}
+
+refresh_timer:
+	_prb_refresh_rx_retire_blk_timer(pkc);
+
+out:
+	spin_unlock(&po->sk.sk_receive_queue.lock);
+}
+
+static void prb_flush_block(struct tpacket_kbdq_core *pkc1,
+		struct tpacket_block_desc *pbd1, __u32 status)
+{
+	/* Flush everything minus the block header */
+
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
+	u8 *start, *end;
+
+	start = (u8 *)pbd1;
+
+	/* Skip the block header(we know header WILL fit in 4K) */
+	start += PAGE_SIZE;
+
+	end = (u8 *)PAGE_ALIGN((unsigned long)pkc1->pkblk_end);
+	for (; start < end; start += PAGE_SIZE)
+		flush_dcache_page(pgv_to_page(start));
+
+	smp_wmb();
+#endif
+
+	/* Now update the block status. */
+
+	BLOCK_STATUS(pbd1) = status;
+
+	/* Flush the block header */
+
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
+	start = (u8 *)pbd1;
+	flush_dcache_page(pgv_to_page(start));
+
+	smp_wmb();
+#endif
+}
+
+/*
+ * Side effect:
+ *
+ * 1) flush the block
+ * 2) Increment active_blk_num
+ *
+ * Note:We DONT refresh the timer on purpose.
+ *	Because almost always the next block will be opened.
+ */
+static void prb_close_block(struct tpacket_kbdq_core *pkc1,
+		struct tpacket_block_desc *pbd1,
+		struct packet_sock *po, unsigned int stat)
+{
+	__u32 status = TP_STATUS_USER | stat;
+
+	struct tpacket3_hdr *last_pkt;
+	struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
+	struct sock *sk = &po->sk;
+
+	if (po->stats.stats3.tp_drops)
+		status |= TP_STATUS_LOSING;
+
+	last_pkt = (struct tpacket3_hdr *)pkc1->prev;
+	last_pkt->tp_next_offset = 0;
+
+	/* Get the ts of the last pkt */
+	if (BLOCK_NUM_PKTS(pbd1)) {
+		h1->ts_last_pkt.ts_sec = last_pkt->tp_sec;
+		h1->ts_last_pkt.ts_nsec	= last_pkt->tp_nsec;
+	} else {
+		/* Ok, we tmo'd - so get the current time.
+		 *
+		 * It shouldn't really happen as we don't close empty
+		 * blocks. See prb_retire_rx_blk_timer_expired().
+		 */
+		struct timespec ts;
+		getnstimeofday(&ts);
+		h1->ts_last_pkt.ts_sec = ts.tv_sec;
+		h1->ts_last_pkt.ts_nsec	= ts.tv_nsec;
+	}
+
+	smp_wmb();
+
+	/* Flush the block */
+	prb_flush_block(pkc1, pbd1, status);
+
+	sk->sk_data_ready(sk);
+
+	pkc1->kactive_blk_num = GET_NEXT_PRB_BLK_NUM(pkc1);
+}
+
+static void prb_thaw_queue(struct tpacket_kbdq_core *pkc)
+{
+	pkc->reset_pending_on_curr_blk = 0;
+}
+
+/*
+ * Side effect of opening a block:
+ *
+ * 1) prb_queue is thawed.
+ * 2) retire_blk_timer is refreshed.
+ *
+ */
+static void prb_open_block(struct tpacket_kbdq_core *pkc1,
+	struct tpacket_block_desc *pbd1)
+{
+	struct timespec ts;
+	struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
+
+	smp_rmb();
+
+	/* We could have just memset this but we will lose the
+	 * flexibility of making the priv area sticky
+	 */
+
+	BLOCK_SNUM(pbd1) = pkc1->knxt_seq_num++;
+	BLOCK_NUM_PKTS(pbd1) = 0;
+	BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
+
+	getnstimeofday(&ts);
+
+	h1->ts_first_pkt.ts_sec = ts.tv_sec;
+	h1->ts_first_pkt.ts_nsec = ts.tv_nsec;
+
+	pkc1->pkblk_start = (char *)pbd1;
+	pkc1->nxt_offset = pkc1->pkblk_start + BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
+
+	BLOCK_O2FP(pbd1) = (__u32)BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
+	BLOCK_O2PRIV(pbd1) = BLK_HDR_LEN;
+
+	pbd1->version = pkc1->version;
+	pkc1->prev = pkc1->nxt_offset;
+	pkc1->pkblk_end = pkc1->pkblk_start + pkc1->kblk_size;
+
+	prb_thaw_queue(pkc1);
+	_prb_refresh_rx_retire_blk_timer(pkc1);
+
+	smp_wmb();
+}
+
+/*
+ * Queue freeze logic:
+ * 1) Assume tp_block_nr = 8 blocks.
+ * 2) At time 't0', user opens Rx ring.
+ * 3) Some time past 't0', kernel starts filling blocks starting from 0 .. 7
+ * 4) user-space is either sleeping or processing block '0'.
+ * 5) tpacket_rcv is currently filling block '7', since there is no space left,
+ *    it will close block-7,loop around and try to fill block '0'.
+ *    call-flow:
+ *    __packet_lookup_frame_in_block
+ *      prb_retire_current_block()
+ *      prb_dispatch_next_block()
+ *        |->(BLOCK_STATUS == USER) evaluates to true
+ *    5.1) Since block-0 is currently in-use, we just freeze the queue.
+ * 6) Now there are two cases:
+ *    6.1) Link goes idle right after the queue is frozen.
+ *         But remember, the last open_block() refreshed the timer.
+ *         When this timer expires,it will refresh itself so that we can
+ *         re-open block-0 in near future.
+ *    6.2) Link is busy and keeps on receiving packets. This is a simple
+ *         case and __packet_lookup_frame_in_block will check if block-0
+ *         is free and can now be re-used.
+ */
+static void prb_freeze_queue(struct tpacket_kbdq_core *pkc,
+				  struct packet_sock *po)
+{
+	pkc->reset_pending_on_curr_blk = 1;
+	po->stats.stats3.tp_freeze_q_cnt++;
+}
+
+#define TOTAL_PKT_LEN_INCL_ALIGN(length) (ALIGN((length), V3_ALIGNMENT))
+
+/*
+ * If the next block is free then we will dispatch it
+ * and return a good offset.
+ * Else, we will freeze the queue.
+ * So, caller must check the return value.
+ */
+static void *prb_dispatch_next_block(struct tpacket_kbdq_core *pkc,
+		struct packet_sock *po)
+{
+	struct tpacket_block_desc *pbd;
+
+	smp_rmb();
+
+	/* 1. Get current block num */
+	pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
+
+	/* 2. If this block is currently in_use then freeze the queue */
+	if (TP_STATUS_USER & BLOCK_STATUS(pbd)) {
+		prb_freeze_queue(pkc, po);
+		return NULL;
+	}
+
+	/*
+	 * 3.
+	 * open this block and return the offset where the first packet
+	 * needs to get stored.
+	 */
+	prb_open_block(pkc, pbd);
+	return (void *)pkc->nxt_offset;
+}
+
+static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
+		struct packet_sock *po, unsigned int status)
+{
+	struct tpacket_block_desc *pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
+
+	/* retire/close the current block */
+	if (likely(TP_STATUS_KERNEL == BLOCK_STATUS(pbd))) {
+		/*
+		 * Plug the case where copy_bits() is in progress on
+		 * cpu-0 and tpacket_rcv() got invoked on cpu-1, didn't
+		 * have space to copy the pkt in the current block and
+		 * called prb_retire_current_block()
+		 *
+		 * We don't need to worry about the TMO case because
+		 * the timer-handler already handled this case.
+		 */
+		if (!(status & TP_STATUS_BLK_TMO)) {
+			while (atomic_read(&pkc->blk_fill_in_prog)) {
+				/* Waiting for skb_copy_bits to finish... */
+				cpu_relax();
+			}
+		}
+		prb_close_block(pkc, pbd, po, status);
+		return;
+	}
+}
+
+static int prb_curr_blk_in_use(struct tpacket_kbdq_core *pkc,
+				      struct tpacket_block_desc *pbd)
+{
+	return TP_STATUS_USER & BLOCK_STATUS(pbd);
+}
+
+static int prb_queue_frozen(struct tpacket_kbdq_core *pkc)
+{
+	return pkc->reset_pending_on_curr_blk;
+}
+
+static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
+{
+	struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
+	atomic_dec(&pkc->blk_fill_in_prog);
+}
+
+static void prb_fill_rxhash(struct tpacket_kbdq_core *pkc,
+			struct tpacket3_hdr *ppd)
+{
+	ppd->hv1.tp_rxhash = skb_get_hash(pkc->skb);
+}
+
+static void prb_clear_rxhash(struct tpacket_kbdq_core *pkc,
+			struct tpacket3_hdr *ppd)
+{
+	ppd->hv1.tp_rxhash = 0;
+}
+
+static void prb_fill_vlan_info(struct tpacket_kbdq_core *pkc,
+			struct tpacket3_hdr *ppd)
+{
+	if (skb_vlan_tag_present(pkc->skb)) {
+		ppd->hv1.tp_vlan_tci = skb_vlan_tag_get(pkc->skb);
+		ppd->hv1.tp_vlan_tpid = ntohs(pkc->skb->vlan_proto);
+		ppd->tp_status = TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
+	} else {
+		ppd->hv1.tp_vlan_tci = 0;
+		ppd->hv1.tp_vlan_tpid = 0;
+		ppd->tp_status = TP_STATUS_AVAILABLE;
+	}
+}
+
+static void prb_run_all_ft_ops(struct tpacket_kbdq_core *pkc,
+			struct tpacket3_hdr *ppd)
+{
+	ppd->hv1.tp_padding = 0;
+	prb_fill_vlan_info(pkc, ppd);
+
+	if (pkc->feature_req_word & TP_FT_REQ_FILL_RXHASH)
+		prb_fill_rxhash(pkc, ppd);
+	else
+		prb_clear_rxhash(pkc, ppd);
+}
+
+static void prb_fill_curr_block(char *curr,
+				struct tpacket_kbdq_core *pkc,
+				struct tpacket_block_desc *pbd,
+				unsigned int len)
+{
+	struct tpacket3_hdr *ppd;
+
+	ppd  = (struct tpacket3_hdr *)curr;
+	ppd->tp_next_offset = TOTAL_PKT_LEN_INCL_ALIGN(len);
+	pkc->prev = curr;
+	pkc->nxt_offset += TOTAL_PKT_LEN_INCL_ALIGN(len);
+	BLOCK_LEN(pbd) += TOTAL_PKT_LEN_INCL_ALIGN(len);
+	BLOCK_NUM_PKTS(pbd) += 1;
+	atomic_inc(&pkc->blk_fill_in_prog);
+	prb_run_all_ft_ops(pkc, ppd);
+}
+
+/* Assumes caller has the sk->rx_queue.lock */
+static void *__packet_lookup_frame_in_block(struct packet_sock *po,
+					    struct sk_buff *skb,
+						int status,
+					    unsigned int len
+					    )
+{
+	struct tpacket_kbdq_core *pkc;
+	struct tpacket_block_desc *pbd;
+	char *curr, *end;
+
+	pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
+	pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
+
+	/* Queue is frozen when user space is lagging behind */
+	if (prb_queue_frozen(pkc)) {
+		/*
+		 * Check if that last block which caused the queue to freeze,
+		 * is still in_use by user-space.
+		 */
+		if (prb_curr_blk_in_use(pkc, pbd)) {
+			/* Can't record this packet */
+			return NULL;
+		} else {
+			/*
+			 * Ok, the block was released by user-space.
+			 * Now let's open that block.
+			 * opening a block also thaws the queue.
+			 * Thawing is a side effect.
+			 */
+			prb_open_block(pkc, pbd);
+		}
+	}
+
+	smp_mb();
+	curr = pkc->nxt_offset;
+	pkc->skb = skb;
+	end = (char *)pbd + pkc->kblk_size;
+
+	/* first try the current block */
+	if (curr+TOTAL_PKT_LEN_INCL_ALIGN(len) < end) {
+		prb_fill_curr_block(curr, pkc, pbd, len);
+		return (void *)curr;
+	}
+
+	/* Ok, close the current block */
+	prb_retire_current_block(pkc, po, 0);
+
+	/* Now, try to dispatch the next block */
+	curr = (char *)prb_dispatch_next_block(pkc, po);
+	if (curr) {
+		pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
+		prb_fill_curr_block(curr, pkc, pbd, len);
+		return (void *)curr;
+	}
+
+	/*
+	 * No free blocks are available.user_space hasn't caught up yet.
+	 * Queue was just frozen and now this packet will get dropped.
+	 */
+	return NULL;
+}
+
+static void *packet_current_rx_frame(struct packet_sock *po,
+					    struct sk_buff *skb,
+					    int status, unsigned int len)
+{
+	char *curr = NULL;
+	switch (po->tp_version) {
+	case TPACKET_V1:
+	case TPACKET_V2:
+		curr = packet_lookup_frame(po, &po->rx_ring,
+					po->rx_ring.head, status);
+		return curr;
+	case TPACKET_V3:
+		return __packet_lookup_frame_in_block(po, skb, status, len);
+	default:
+		WARN(1, "TPACKET version not supported\n");
+		BUG();
+		return NULL;
+	}
+}
+
+static void *prb_lookup_block(struct packet_sock *po,
+				     struct packet_ring_buffer *rb,
+				     unsigned int idx,
+				     int status)
+{
+	struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
+	struct tpacket_block_desc *pbd = GET_PBLOCK_DESC(pkc, idx);
+
+	if (status != BLOCK_STATUS(pbd))
+		return NULL;
+	return pbd;
+}
+
+static int prb_previous_blk_num(struct packet_ring_buffer *rb)
+{
+	unsigned int prev;
+	if (rb->prb_bdqc.kactive_blk_num)
+		prev = rb->prb_bdqc.kactive_blk_num-1;
+	else
+		prev = rb->prb_bdqc.knum_blocks-1;
+	return prev;
+}
+
+/* Assumes caller has held the rx_queue.lock */
+static void *__prb_previous_block(struct packet_sock *po,
+					 struct packet_ring_buffer *rb,
+					 int status)
+{
+	unsigned int previous = prb_previous_blk_num(rb);
+	return prb_lookup_block(po, rb, previous, status);
+}
+
+static void *packet_previous_rx_frame(struct packet_sock *po,
+					     struct packet_ring_buffer *rb,
+					     int status)
+{
+	if (po->tp_version <= TPACKET_V2)
+		return packet_previous_frame(po, rb, status);
+
+	return __prb_previous_block(po, rb, status);
+}
+
+static void packet_increment_rx_head(struct packet_sock *po,
+					    struct packet_ring_buffer *rb)
+{
+	switch (po->tp_version) {
+	case TPACKET_V1:
+	case TPACKET_V2:
+		return packet_increment_head(rb);
+	case TPACKET_V3:
+	default:
+		WARN(1, "TPACKET version not supported.\n");
+		BUG();
+		return;
+	}
+}
+
+static void *packet_previous_frame(struct packet_sock *po,
+		struct packet_ring_buffer *rb,
+		int status)
+{
+	unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
+	return packet_lookup_frame(po, rb, previous, status);
+}
+
+static void packet_increment_head(struct packet_ring_buffer *buff)
+{
+	buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
+}
+
+static void packet_inc_pending(struct packet_ring_buffer *rb)
+{
+	this_cpu_inc(*rb->pending_refcnt);
+}
+
+static void packet_dec_pending(struct packet_ring_buffer *rb)
+{
+	this_cpu_dec(*rb->pending_refcnt);
+}
+
+static unsigned int packet_read_pending(const struct packet_ring_buffer *rb)
+{
+	unsigned int refcnt = 0;
+	int cpu;
+
+	/* We don't use pending refcount in rx_ring. */
+	if (rb->pending_refcnt == NULL)
+		return 0;
+
+	for_each_possible_cpu(cpu)
+		refcnt += *per_cpu_ptr(rb->pending_refcnt, cpu);
+
+	return refcnt;
+}
+
+static int packet_alloc_pending(struct packet_sock *po)
+{
+	po->rx_ring.pending_refcnt = NULL;
+
+	po->tx_ring.pending_refcnt = alloc_percpu(unsigned int);
+	if (unlikely(po->tx_ring.pending_refcnt == NULL))
+		return -ENOBUFS;
+
+	return 0;
+}
+
+static void packet_free_pending(struct packet_sock *po)
+{
+	free_percpu(po->tx_ring.pending_refcnt);
+}
+
+static bool packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
+{
+	struct sock *sk = &po->sk;
+	bool has_room;
+
+	if (po->prot_hook.func != tpacket_rcv)
+		return (atomic_read(&sk->sk_rmem_alloc) + skb->truesize)
+			<= sk->sk_rcvbuf;
+
+	spin_lock(&sk->sk_receive_queue.lock);
+	if (po->tp_version == TPACKET_V3)
+		has_room = prb_lookup_block(po, &po->rx_ring,
+					    po->rx_ring.prb_bdqc.kactive_blk_num,
+					    TP_STATUS_KERNEL);
+	else
+		has_room = packet_lookup_frame(po, &po->rx_ring,
+					       po->rx_ring.head,
+					       TP_STATUS_KERNEL);
+	spin_unlock(&sk->sk_receive_queue.lock);
+
+	return has_room;
+}
+
+static void packet_sock_destruct(struct sock *sk)
+{
+	skb_queue_purge(&sk->sk_error_queue);
+
+	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
+	WARN_ON(atomic_read(&sk->sk_wmem_alloc));
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		pr_err("Attempt to release alive packet socket: %p\n", sk);
+		return;
+	}
+
+	sk_refcnt_debug_dec(sk);
+}
+
+static unsigned int fanout_demux_hash(struct packet_fanout *f,
+				      struct sk_buff *skb,
+				      unsigned int num)
+{
+	return reciprocal_scale(skb_get_hash(skb), num);
+}
+
+static unsigned int fanout_demux_lb(struct packet_fanout *f,
+				    struct sk_buff *skb,
+				    unsigned int num)
+{
+	unsigned int val = atomic_inc_return(&f->rr_cur);
+
+	return val % num;
+}
+
+static unsigned int fanout_demux_cpu(struct packet_fanout *f,
+				     struct sk_buff *skb,
+				     unsigned int num)
+{
+	return smp_processor_id() % num;
+}
+
+static unsigned int fanout_demux_rnd(struct packet_fanout *f,
+				     struct sk_buff *skb,
+				     unsigned int num)
+{
+	return prandom_u32_max(num);
+}
+
+static unsigned int fanout_demux_rollover(struct packet_fanout *f,
+					  struct sk_buff *skb,
+					  unsigned int idx, unsigned int skip,
+					  unsigned int num)
+{
+	unsigned int i, j;
+
+	i = j = min_t(int, f->next[idx], num - 1);
+	do {
+		if (i != skip && packet_rcv_has_room(pkt_sk(f->arr[i]), skb)) {
+			if (i != j)
+				f->next[idx] = i;
+			return i;
+		}
+		if (++i == num)
+			i = 0;
+	} while (i != j);
+
+	return idx;
+}
+
+static unsigned int fanout_demux_qm(struct packet_fanout *f,
+				    struct sk_buff *skb,
+				    unsigned int num)
+{
+	return skb_get_queue_mapping(skb) % num;
+}
+
+static bool fanout_has_flag(struct packet_fanout *f, u16 flag)
+{
+	return f->flags & (flag >> 8);
+}
+
+static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
+			     struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct packet_fanout *f = pt->af_packet_priv;
+	unsigned int num = READ_ONCE(f->num_members);
+	struct packet_sock *po;
+	unsigned int idx;
+
+	if (!net_eq(dev_net(dev), read_pnet(&f->net)) ||
+	    !num) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
+		skb = ip_check_defrag(skb, IP_DEFRAG_AF_PACKET);
+		if (!skb)
+			return 0;
+	}
+	switch (f->type) {
+	case PACKET_FANOUT_HASH:
+	default:
+		idx = fanout_demux_hash(f, skb, num);
+		break;
+	case PACKET_FANOUT_LB:
+		idx = fanout_demux_lb(f, skb, num);
+		break;
+	case PACKET_FANOUT_CPU:
+		idx = fanout_demux_cpu(f, skb, num);
+		break;
+	case PACKET_FANOUT_RND:
+		idx = fanout_demux_rnd(f, skb, num);
+		break;
+	case PACKET_FANOUT_QM:
+		idx = fanout_demux_qm(f, skb, num);
+		break;
+	case PACKET_FANOUT_ROLLOVER:
+		idx = fanout_demux_rollover(f, skb, 0, (unsigned int) -1, num);
+		break;
+	}
+
+	po = pkt_sk(f->arr[idx]);
+	if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER) &&
+	    unlikely(!packet_rcv_has_room(po, skb))) {
+		idx = fanout_demux_rollover(f, skb, idx, idx, num);
+		po = pkt_sk(f->arr[idx]);
+	}
+
+	return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
+}
+
+DEFINE_MUTEX(fanout_mutex);
+EXPORT_SYMBOL_GPL(fanout_mutex);
+static LIST_HEAD(fanout_list);
+
+static void __fanout_link(struct sock *sk, struct packet_sock *po)
+{
+	struct packet_fanout *f = po->fanout;
+
+	spin_lock(&f->lock);
+	f->arr[f->num_members] = sk;
+	smp_wmb();
+	f->num_members++;
+	spin_unlock(&f->lock);
+}
+
+static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
+{
+	struct packet_fanout *f = po->fanout;
+	int i;
+
+	spin_lock(&f->lock);
+	for (i = 0; i < f->num_members; i++) {
+		if (f->arr[i] == sk)
+			break;
+	}
+	BUG_ON(i >= f->num_members);
+	f->arr[i] = f->arr[f->num_members - 1];
+	f->num_members--;
+	spin_unlock(&f->lock);
+}
+
+static bool match_fanout_group(struct packet_type *ptype, struct sock *sk)
+{
+	if (ptype->af_packet_priv == (void *)((struct packet_sock *)sk)->fanout)
+		return true;
+
+	return false;
+}
+
+static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
+{
+	struct packet_sock *po = pkt_sk(sk);
+	struct packet_fanout *f, *match;
+	u8 type = type_flags & 0xff;
+	u8 flags = type_flags >> 8;
+	int err;
+
+	switch (type) {
+	case PACKET_FANOUT_ROLLOVER:
+		if (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)
+			return -EINVAL;
+	case PACKET_FANOUT_HASH:
+	case PACKET_FANOUT_LB:
+	case PACKET_FANOUT_CPU:
+	case PACKET_FANOUT_RND:
+	case PACKET_FANOUT_QM:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (!po->running)
+		return -EINVAL;
+
+	if (po->fanout)
+		return -EALREADY;
+
+	mutex_lock(&fanout_mutex);
+	match = NULL;
+	list_for_each_entry(f, &fanout_list, list) {
+		if (f->id == id &&
+		    read_pnet(&f->net) == sock_net(sk)) {
+			match = f;
+			break;
+		}
+	}
+	err = -EINVAL;
+	if (match && match->flags != flags)
+		goto out;
+	if (!match) {
+		err = -ENOMEM;
+		match = kzalloc(sizeof(*match), GFP_KERNEL);
+		if (!match)
+			goto out;
+		write_pnet(&match->net, sock_net(sk));
+		match->id = id;
+		match->type = type;
+		match->flags = flags;
+		atomic_set(&match->rr_cur, 0);
+		INIT_LIST_HEAD(&match->list);
+		spin_lock_init(&match->lock);
+		atomic_set(&match->sk_ref, 0);
+		match->prot_hook.type = po->prot_hook.type;
+		match->prot_hook.dev = po->prot_hook.dev;
+		match->prot_hook.func = packet_rcv_fanout;
+		match->prot_hook.af_packet_priv = match;
+		match->prot_hook.id_match = match_fanout_group;
+		dev_add_pack(&match->prot_hook);
+		list_add(&match->list, &fanout_list);
+	}
+	err = -EINVAL;
+	if (match->type == type &&
+	    match->prot_hook.type == po->prot_hook.type &&
+	    match->prot_hook.dev == po->prot_hook.dev) {
+		err = -ENOSPC;
+		if (atomic_read(&match->sk_ref) < PACKET_FANOUT_MAX) {
+			__dev_remove_pack(&po->prot_hook);
+			po->fanout = match;
+			atomic_inc(&match->sk_ref);
+			__fanout_link(sk, po);
+			err = 0;
+		}
+	}
+out:
+	mutex_unlock(&fanout_mutex);
+	return err;
+}
+
+static void fanout_release(struct sock *sk)
+{
+	struct packet_sock *po = pkt_sk(sk);
+	struct packet_fanout *f;
+
+	f = po->fanout;
+	if (!f)
+		return;
+
+	mutex_lock(&fanout_mutex);
+	po->fanout = NULL;
+
+	if (atomic_dec_and_test(&f->sk_ref)) {
+		list_del(&f->list);
+		dev_remove_pack(&f->prot_hook);
+		kfree(f);
+	}
+	mutex_unlock(&fanout_mutex);
+}
+
+static const struct proto_ops packet_ops;
+
+static const struct proto_ops packet_ops_spkt;
+
+static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
+			   struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct sock *sk;
+	struct sockaddr_pkt *spkt;
+
+	/*
+	 *	When we registered the protocol we saved the socket in the data
+	 *	field for just this event.
+	 */
+
+	sk = pt->af_packet_priv;
+
+	/*
+	 *	Yank back the headers [hope the device set this
+	 *	right or kerboom...]
+	 *
+	 *	Incoming packets have ll header pulled,
+	 *	push it back.
+	 *
+	 *	For outgoing ones skb->data == skb_mac_header(skb)
+	 *	so that this procedure is noop.
+	 */
+
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		goto out;
+
+	if (!net_eq(dev_net(dev), sock_net(sk)))
+		goto out;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		goto oom;
+
+	/* drop any routing info */
+	skb_dst_drop(skb);
+
+	/* drop conntrack reference */
+	nf_reset(skb);
+
+	spkt = &PACKET_SKB_CB(skb)->sa.pkt;
+
+	skb_push(skb, skb->data - skb_mac_header(skb));
+
+	/*
+	 *	The SOCK_PACKET socket receives _all_ frames.
+	 */
+
+	spkt->spkt_family = dev->type;
+	strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
+	spkt->spkt_protocol = skb->protocol;
+
+	/*
+	 *	Charge the memory to the socket. This is done specifically
+	 *	to prevent sockets using all the memory up.
+	 */
+
+	if (sock_queue_rcv_skb(sk, skb) == 0)
+		return 0;
+
+out:
+	kfree_skb(skb);
+oom:
+	return 0;
+}
+
+
+/*
+ *	Output a raw packet to a device layer. This bypasses all the other
+ *	protocol layers and you must therefore supply it with a complete frame
+ */
+
+static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg,
+			       size_t len)
+{
+	struct sock *sk = sock->sk;
+	DECLARE_SOCKADDR(struct sockaddr_pkt *, saddr, msg->msg_name);
+	struct sk_buff *skb = NULL;
+	struct net_device *dev;
+	__be16 proto = 0;
+	int err;
+	int extra_len = 0;
+
+	/*
+	 *	Get and verify the address.
+	 */
+
+	if (saddr) {
+		if (msg->msg_namelen < sizeof(struct sockaddr))
+			return -EINVAL;
+		if (msg->msg_namelen == sizeof(struct sockaddr_pkt))
+			proto = saddr->spkt_protocol;
+	} else
+		return -ENOTCONN;	/* SOCK_PACKET must be sent giving an address */
+
+	/*
+	 *	Find the device first to size check it
+	 */
+
+	saddr->spkt_device[sizeof(saddr->spkt_device) - 1] = 0;
+retry:
+	rcu_read_lock();
+	dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
+	err = -ENODEV;
+	if (dev == NULL)
+		goto out_unlock;
+
+	err = -ENETDOWN;
+	if (!(dev->flags & IFF_UP))
+		goto out_unlock;
+
+	/*
+	 * You may not queue a frame bigger than the mtu. This is the lowest level
+	 * raw protocol and you must do your own fragmentation at this level.
+	 */
+
+	if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
+		if (!netif_supports_nofcs(dev)) {
+			err = -EPROTONOSUPPORT;
+			goto out_unlock;
+		}
+		extra_len = 4; /* We're doing our own CRC */
+	}
+
+	err = -EMSGSIZE;
+	if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN + extra_len)
+		goto out_unlock;
+
+	if (!skb) {
+		size_t reserved = LL_RESERVED_SPACE(dev);
+		int tlen = dev->needed_tailroom;
+		unsigned int hhlen = dev->header_ops ? dev->hard_header_len : 0;
+
+		rcu_read_unlock();
+		skb = sock_wmalloc(sk, len + reserved + tlen, 0, GFP_KERNEL);
+		if (skb == NULL)
+			return -ENOBUFS;
+		/* FIXME: Save some space for broken drivers that write a hard
+		 * header at transmission time by themselves. PPP is the notable
+		 * one here. This should really be fixed at the driver level.
+		 */
+		skb_reserve(skb, reserved);
+		skb_reset_network_header(skb);
+
+		/* Try to align data part correctly */
+		if (hhlen) {
+			skb->data -= hhlen;
+			skb->tail -= hhlen;
+			if (len < hhlen)
+				skb_reset_network_header(skb);
+		}
+		err = memcpy_from_msg(skb_put(skb, len), msg, len);
+		if (err)
+			goto out_free;
+		goto retry;
+	}
+
+	if (len > (dev->mtu + dev->hard_header_len + extra_len)) {
+		/* Earlier code assumed this would be a VLAN pkt,
+		 * double-check this now that we have the actual
+		 * packet in hand.
+		 */
+		struct ethhdr *ehdr;
+		skb_reset_mac_header(skb);
+		ehdr = eth_hdr(skb);
+		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+			err = -EMSGSIZE;
+			goto out_unlock;
+		}
+	}
+
+	skb->protocol = proto;
+	skb->dev = dev;
+	skb->priority = sk->sk_priority;
+	skb->mark = sk->sk_mark;
+
+	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
+
+	if (unlikely(extra_len == 4))
+		skb->no_fcs = 1;
+
+	skb_probe_transport_header(skb, 0);
+
+	dev_queue_xmit(skb);
+	rcu_read_unlock();
+	return len;
+
+out_unlock:
+	rcu_read_unlock();
+out_free:
+	kfree_skb(skb);
+	return err;
+}
+
+static unsigned int run_filter(const struct sk_buff *skb,
+				      const struct sock *sk,
+				      unsigned int res)
+{
+	struct sk_filter *filter;
+
+	rcu_read_lock();
+	filter = rcu_dereference(sk->sk_filter);
+	if (filter != NULL)
+		res = SK_RUN_FILTER(filter, skb);
+	rcu_read_unlock();
+
+	return res;
+}
+
+/*
+ * This function makes lazy skb cloning in hope that most of packets
+ * are discarded by BPF.
+ *
+ * Note tricky part: we DO mangle shared skb! skb->data, skb->len
+ * and skb->cb are mangled. It works because (and until) packets
+ * falling here are owned by current CPU. Output packets are cloned
+ * by dev_queue_xmit_nit(), input packets are processed by net_bh
+ * sequencially, so that if we return skb to original state on exit,
+ * we will not harm anyone.
+ */
+
+static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
+		      struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct sock *sk;
+	struct sockaddr_ll *sll;
+	struct packet_sock *po;
+	u8 *skb_head = skb->data;
+	int skb_len = skb->len;
+	unsigned int snaplen, res;
+
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		goto drop;
+
+	sk = pt->af_packet_priv;
+	po = pkt_sk(sk);
+
+	if (!net_eq(dev_net(dev), sock_net(sk)))
+		goto drop;
+
+	skb->dev = dev;
+
+	if (dev->header_ops) {
+		/* The device has an explicit notion of ll header,
+		 * exported to higher levels.
+		 *
+		 * Otherwise, the device hides details of its frame
+		 * structure, so that corresponding packet head is
+		 * never delivered to user.
+		 */
+		if (sk->sk_type != SOCK_DGRAM)
+			skb_push(skb, skb->data - skb_mac_header(skb));
+		else if (skb->pkt_type == PACKET_OUTGOING) {
+			/* Special case: outgoing packets have ll header at head */
+			skb_pull(skb, skb_network_offset(skb));
+		}
+	}
+
+	snaplen = skb->len;
+
+	res = run_filter(skb, sk, snaplen);
+	if (!res)
+		goto drop_n_restore;
+	if (snaplen > res)
+		snaplen = res;
+
+	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
+		goto drop_n_acct;
+
+	if (skb_shared(skb)) {
+		struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
+		if (nskb == NULL)
+			goto drop_n_acct;
+
+		if (skb_head != skb->data) {
+			skb->data = skb_head;
+			skb->len = skb_len;
+		}
+		consume_skb(skb);
+		skb = nskb;
+	}
+
+	sock_skb_cb_check_size(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8);
+
+	sll = &PACKET_SKB_CB(skb)->sa.ll;
+	sll->sll_hatype = dev->type;
+	sll->sll_pkttype = skb->pkt_type;
+	if (unlikely(po->origdev))
+		sll->sll_ifindex = orig_dev->ifindex;
+	else
+		sll->sll_ifindex = dev->ifindex;
+
+	sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
+
+	/* sll->sll_family and sll->sll_protocol are set in packet_recvmsg().
+	 * Use their space for storing the original skb length.
+	 */
+	PACKET_SKB_CB(skb)->sa.origlen = skb->len;
+
+	if (pskb_trim(skb, snaplen))
+		goto drop_n_acct;
+
+	skb_set_owner_r(skb, sk);
+	skb->dev = NULL;
+	skb_dst_drop(skb);
+
+	/* drop conntrack reference */
+	nf_reset(skb);
+
+	spin_lock(&sk->sk_receive_queue.lock);
+	po->stats.stats1.tp_packets++;
+	sock_skb_set_dropcount(sk, skb);
+	__skb_queue_tail(&sk->sk_receive_queue, skb);
+	spin_unlock(&sk->sk_receive_queue.lock);
+	sk->sk_data_ready(sk);
+	return 0;
+
+drop_n_acct:
+	spin_lock(&sk->sk_receive_queue.lock);
+	po->stats.stats1.tp_drops++;
+	atomic_inc(&sk->sk_drops);
+	spin_unlock(&sk->sk_receive_queue.lock);
+
+drop_n_restore:
+	if (skb_head != skb->data && skb_shared(skb)) {
+		skb->data = skb_head;
+		skb->len = skb_len;
+	}
+drop:
+	consume_skb(skb);
+	return 0;
+}
+
+static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
+		       struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct sock *sk;
+	struct packet_sock *po;
+	struct sockaddr_ll *sll;
+	union tpacket_uhdr h;
+	u8 *skb_head = skb->data;
+	int skb_len = skb->len;
+	unsigned int snaplen, res;
+	unsigned long status = TP_STATUS_USER;
+	unsigned short macoff, netoff, hdrlen;
+	struct sk_buff *copy_skb = NULL;
+	struct timespec ts;
+	__u32 ts_status;
+
+	/* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
+	 * We may add members to them until current aligned size without forcing
+	 * userspace to call getsockopt(..., PACKET_HDRLEN, ...).
+	 */
+	BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h2)) != 32);
+	BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h3)) != 48);
+
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		goto drop;
+
+	sk = pt->af_packet_priv;
+	po = pkt_sk(sk);
+
+	if (!net_eq(dev_net(dev), sock_net(sk)))
+		goto drop;
+
+	if (dev->header_ops) {
+		if (sk->sk_type != SOCK_DGRAM)
+			skb_push(skb, skb->data - skb_mac_header(skb));
+		else if (skb->pkt_type == PACKET_OUTGOING) {
+			/* Special case: outgoing packets have ll header at head */
+			skb_pull(skb, skb_network_offset(skb));
+		}
+	}
+
+	snaplen = skb->len;
+
+	res = run_filter(skb, sk, snaplen);
+	if (!res)
+		goto drop_n_restore;
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		status |= TP_STATUS_CSUMNOTREADY;
+	else if (skb->pkt_type != PACKET_OUTGOING &&
+		 (skb->ip_summed == CHECKSUM_COMPLETE ||
+		  skb_csum_unnecessary(skb)))
+		status |= TP_STATUS_CSUM_VALID;
+
+	if (snaplen > res)
+		snaplen = res;
+
+	if (sk->sk_type == SOCK_DGRAM) {
+		macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
+				  po->tp_reserve;
+	} else {
+		unsigned int maclen = skb_network_offset(skb);
+		netoff = TPACKET_ALIGN(po->tp_hdrlen +
+				       (maclen < 16 ? 16 : maclen)) +
+			po->tp_reserve;
+		macoff = netoff - maclen;
+	}
+	if (po->tp_version <= TPACKET_V2) {
+		if (macoff + snaplen > po->rx_ring.frame_size) {
+			if (po->copy_thresh &&
+			    atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
+				if (skb_shared(skb)) {
+					copy_skb = skb_clone(skb, GFP_ATOMIC);
+				} else {
+					copy_skb = skb_get(skb);
+					skb_head = skb->data;
+				}
+				if (copy_skb)
+					skb_set_owner_r(copy_skb, sk);
+			}
+			snaplen = po->rx_ring.frame_size - macoff;
+			if ((int)snaplen < 0)
+				snaplen = 0;
+		}
+	} else if (unlikely(macoff + snaplen >
+			    GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len)) {
+		u32 nval;
+
+		nval = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len - macoff;
+		pr_err_once("tpacket_rcv: packet too big, clamped from %u to %u. macoff=%u\n",
+			    snaplen, nval, macoff);
+		snaplen = nval;
+		if (unlikely((int)snaplen < 0)) {
+			snaplen = 0;
+			macoff = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len;
+		}
+	}
+	spin_lock(&sk->sk_receive_queue.lock);
+	h.raw = packet_current_rx_frame(po, skb,
+					TP_STATUS_KERNEL, (macoff+snaplen));
+	if (!h.raw)
+		goto ring_is_full;
+	if (po->tp_version <= TPACKET_V2) {
+		packet_increment_rx_head(po, &po->rx_ring);
+	/*
+	 * LOSING will be reported till you read the stats,
+	 * because it's COR - Clear On Read.
+	 * Anyways, moving it for V1/V2 only as V3 doesn't need this
+	 * at packet level.
+	 */
+		if (po->stats.stats1.tp_drops)
+			status |= TP_STATUS_LOSING;
+	}
+	po->stats.stats1.tp_packets++;
+	if (copy_skb) {
+		status |= TP_STATUS_COPY;
+		__skb_queue_tail(&sk->sk_receive_queue, copy_skb);
+	}
+	spin_unlock(&sk->sk_receive_queue.lock);
+
+	skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
+
+	if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
+		getnstimeofday(&ts);
+
+	status |= ts_status;
+
+	switch (po->tp_version) {
+	case TPACKET_V1:
+		h.h1->tp_len = skb->len;
+		h.h1->tp_snaplen = snaplen;
+		h.h1->tp_mac = macoff;
+		h.h1->tp_net = netoff;
+		h.h1->tp_sec = ts.tv_sec;
+		h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
+		hdrlen = sizeof(*h.h1);
+		break;
+	case TPACKET_V2:
+		h.h2->tp_len = skb->len;
+		h.h2->tp_snaplen = snaplen;
+		h.h2->tp_mac = macoff;
+		h.h2->tp_net = netoff;
+		h.h2->tp_sec = ts.tv_sec;
+		h.h2->tp_nsec = ts.tv_nsec;
+		if (skb_vlan_tag_present(skb)) {
+			h.h2->tp_vlan_tci = skb_vlan_tag_get(skb);
+			h.h2->tp_vlan_tpid = ntohs(skb->vlan_proto);
+			status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
+		} else {
+			h.h2->tp_vlan_tci = 0;
+			h.h2->tp_vlan_tpid = 0;
+		}
+		memset(h.h2->tp_padding, 0, sizeof(h.h2->tp_padding));
+		hdrlen = sizeof(*h.h2);
+		break;
+	case TPACKET_V3:
+		/* tp_nxt_offset,vlan are already populated above.
+		 * So DONT clear those fields here
+		 */
+		h.h3->tp_status |= status;
+		h.h3->tp_len = skb->len;
+		h.h3->tp_snaplen = snaplen;
+		h.h3->tp_mac = macoff;
+		h.h3->tp_net = netoff;
+		h.h3->tp_sec  = ts.tv_sec;
+		h.h3->tp_nsec = ts.tv_nsec;
+		memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding));
+		hdrlen = sizeof(*h.h3);
+		break;
+	default:
+		BUG();
+	}
+
+	sll = h.raw + TPACKET_ALIGN(hdrlen);
+	sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
+	sll->sll_family = AF_PACKET;
+	sll->sll_hatype = dev->type;
+	sll->sll_protocol = skb->protocol;
+	sll->sll_pkttype = skb->pkt_type;
+	if (unlikely(po->origdev))
+		sll->sll_ifindex = orig_dev->ifindex;
+	else
+		sll->sll_ifindex = dev->ifindex;
+
+	smp_mb();
+
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
+	if (po->tp_version <= TPACKET_V2) {
+		u8 *start, *end;
+
+		end = (u8 *) PAGE_ALIGN((unsigned long) h.raw +
+					macoff + snaplen);
+
+		for (start = h.raw; start < end; start += PAGE_SIZE)
+			flush_dcache_page(pgv_to_page(start));
+	}
+	smp_wmb();
+#endif
+
+	if (po->tp_version <= TPACKET_V2) {
+		__packet_set_status(po, h.raw, status);
+		sk->sk_data_ready(sk);
+	} else {
+		prb_clear_blk_fill_status(&po->rx_ring);
+	}
+
+drop_n_restore:
+	if (skb_head != skb->data && skb_shared(skb)) {
+		skb->data = skb_head;
+		skb->len = skb_len;
+	}
+drop:
+	kfree_skb(skb);
+	return 0;
+
+ring_is_full:
+	po->stats.stats1.tp_drops++;
+	spin_unlock(&sk->sk_receive_queue.lock);
+
+	sk->sk_data_ready(sk);
+	kfree_skb(copy_skb);
+	goto drop_n_restore;
+}
+
+static void tpacket_destruct_skb(struct sk_buff *skb)
+{
+	struct packet_sock *po = pkt_sk(skb->sk);
+
+	if (likely(po->tx_ring.pg_vec)) {
+		void *ph;
+		__u32 ts;
+
+		ph = skb_shinfo(skb)->destructor_arg;
+		packet_dec_pending(&po->tx_ring);
+
+		ts = __packet_set_timestamp(po, ph, skb);
+		__packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts);
+	}
+
+	sock_wfree(skb);
+}
+
+static bool ll_header_truncated(const struct net_device *dev, int len)
+{
+	/* net device doesn't like empty head */
+	if (unlikely(len <= dev->hard_header_len)) {
+		net_warn_ratelimited("%s: packet size is too short (%d <= %d)\n",
+				     current->comm, len, dev->hard_header_len);
+		return true;
+	}
+
+	return false;
+}
+
+static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
+		void *frame, struct net_device *dev, int size_max,
+		__be16 proto, unsigned char *addr, int hlen)
+{
+	union tpacket_uhdr ph;
+	int to_write, offset, len, tp_len, nr_frags, len_max;
+	struct socket *sock = po->sk.sk_socket;
+	struct page *page;
+	void *data;
+	int err;
+
+	ph.raw = frame;
+
+	skb->protocol = proto;
+	skb->dev = dev;
+	skb->priority = po->sk.sk_priority;
+	skb->mark = po->sk.sk_mark;
+	sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags);
+	skb_shinfo(skb)->destructor_arg = ph.raw;
+
+	switch (po->tp_version) {
+	case TPACKET_V2:
+		tp_len = ph.h2->tp_len;
+		break;
+	default:
+		tp_len = ph.h1->tp_len;
+		break;
+	}
+	if (unlikely(tp_len > size_max)) {
+		pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
+		return -EMSGSIZE;
+	}
+
+	skb_reserve(skb, hlen);
+	skb_reset_network_header(skb);
+
+	if (!packet_use_direct_xmit(po))
+		skb_probe_transport_header(skb, 0);
+	if (unlikely(po->tp_tx_has_off)) {
+		int off_min, off_max, off;
+		off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
+		off_max = po->tx_ring.frame_size - tp_len;
+		if (sock->type == SOCK_DGRAM) {
+			switch (po->tp_version) {
+			case TPACKET_V2:
+				off = ph.h2->tp_net;
+				break;
+			default:
+				off = ph.h1->tp_net;
+				break;
+			}
+		} else {
+			switch (po->tp_version) {
+			case TPACKET_V2:
+				off = ph.h2->tp_mac;
+				break;
+			default:
+				off = ph.h1->tp_mac;
+				break;
+			}
+		}
+		if (unlikely((off < off_min) || (off_max < off)))
+			return -EINVAL;
+		data = ph.raw + off;
+	} else {
+		data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
+	}
+	to_write = tp_len;
+
+	if (sock->type == SOCK_DGRAM) {
+		err = dev_hard_header(skb, dev, ntohs(proto), addr,
+				NULL, tp_len);
+		if (unlikely(err < 0))
+			return -EINVAL;
+	} else if (dev->hard_header_len) {
+		if (ll_header_truncated(dev, tp_len))
+			return -EINVAL;
+
+		skb_push(skb, dev->hard_header_len);
+		err = skb_store_bits(skb, 0, data,
+				dev->hard_header_len);
+		if (unlikely(err))
+			return err;
+
+		data += dev->hard_header_len;
+		to_write -= dev->hard_header_len;
+	}
+
+	offset = offset_in_page(data);
+	len_max = PAGE_SIZE - offset;
+	len = ((to_write > len_max) ? len_max : to_write);
+
+	skb->data_len = to_write;
+	skb->len += to_write;
+	skb->truesize += to_write;
+	atomic_add(to_write, &po->sk.sk_wmem_alloc);
+
+	while (likely(to_write)) {
+		nr_frags = skb_shinfo(skb)->nr_frags;
+
+		if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
+			pr_err("Packet exceed the number of skb frags(%lu)\n",
+			       MAX_SKB_FRAGS);
+			return -EFAULT;
+		}
+
+		page = pgv_to_page(data);
+		data += len;
+		flush_dcache_page(page);
+		get_page(page);
+		skb_fill_page_desc(skb, nr_frags, page, offset, len);
+		to_write -= len;
+		offset = 0;
+		len_max = PAGE_SIZE;
+		len = ((to_write > len_max) ? len_max : to_write);
+	}
+
+	return tp_len;
+}
+
+static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
+{
+	struct sk_buff *skb;
+	struct net_device *dev;
+	__be16 proto;
+	int err, reserve = 0;
+	void *ph;
+	DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
+	bool need_wait = !(msg->msg_flags & MSG_DONTWAIT);
+	int tp_len, size_max;
+	unsigned char *addr;
+	int len_sum = 0;
+	int status = TP_STATUS_AVAILABLE;
+	int hlen, tlen;
+
+	mutex_lock(&po->pg_vec_lock);
+
+	if (likely(saddr == NULL)) {
+		dev	= packet_cached_dev_get(po);
+		proto	= po->num;
+		addr	= NULL;
+	} else {
+		err = -EINVAL;
+		if (msg->msg_namelen < sizeof(struct sockaddr_ll))
+			goto out;
+		if (msg->msg_namelen < (saddr->sll_halen
+					+ offsetof(struct sockaddr_ll,
+						sll_addr)))
+			goto out;
+		proto	= saddr->sll_protocol;
+		addr	= saddr->sll_addr;
+		dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
+	}
+
+	err = -ENXIO;
+	if (unlikely(dev == NULL))
+		goto out;
+	err = -ENETDOWN;
+	if (unlikely(!(dev->flags & IFF_UP)))
+		goto out_put;
+
+	reserve = dev->hard_header_len + VLAN_HLEN;
+	size_max = po->tx_ring.frame_size
+		- (po->tp_hdrlen - sizeof(struct sockaddr_ll));
+
+	if (size_max > dev->mtu + reserve)
+		size_max = dev->mtu + reserve;
+
+	do {
+		ph = packet_current_frame(po, &po->tx_ring,
+					  TP_STATUS_SEND_REQUEST);
+		if (unlikely(ph == NULL)) {
+			if (need_wait && need_resched())
+				schedule();
+			continue;
+		}
+
+		status = TP_STATUS_SEND_REQUEST;
+		hlen = LL_RESERVED_SPACE(dev);
+		tlen = dev->needed_tailroom;
+		skb = sock_alloc_send_skb(&po->sk,
+				hlen + tlen + sizeof(struct sockaddr_ll),
+				!need_wait, &err);
+
+		if (unlikely(skb == NULL)) {
+			/* we assume the socket was initially writeable ... */
+			if (likely(len_sum > 0))
+				err = len_sum;
+			goto out_status;
+		}
+		tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
+					  addr, hlen);
+		if (tp_len > dev->mtu + dev->hard_header_len) {
+			struct ethhdr *ehdr;
+			/* Earlier code assumed this would be a VLAN pkt,
+			 * double-check this now that we have the actual
+			 * packet in hand.
+			 */
+
+			skb_reset_mac_header(skb);
+			ehdr = eth_hdr(skb);
+			if (ehdr->h_proto != htons(ETH_P_8021Q))
+				tp_len = -EMSGSIZE;
+		}
+		if (unlikely(tp_len < 0)) {
+			if (po->tp_loss) {
+				__packet_set_status(po, ph,
+						TP_STATUS_AVAILABLE);
+				packet_increment_head(&po->tx_ring);
+				kfree_skb(skb);
+				continue;
+			} else {
+				status = TP_STATUS_WRONG_FORMAT;
+				err = tp_len;
+				goto out_status;
+			}
+		}
+
+		packet_pick_tx_queue(dev, skb);
+
+		skb->destructor = tpacket_destruct_skb;
+		__packet_set_status(po, ph, TP_STATUS_SENDING);
+		packet_inc_pending(&po->tx_ring);
+
+		status = TP_STATUS_SEND_REQUEST;
+		err = po->xmit(skb);
+		if (unlikely(err > 0)) {
+			err = net_xmit_errno(err);
+			if (err && __packet_get_status(po, ph) ==
+				   TP_STATUS_AVAILABLE) {
+				/* skb was destructed already */
+				skb = NULL;
+				goto out_status;
+			}
+			/*
+			 * skb was dropped but not destructed yet;
+			 * let's treat it like congestion or err < 0
+			 */
+			err = 0;
+		}
+		packet_increment_head(&po->tx_ring);
+		len_sum += tp_len;
+	} while (likely((ph != NULL) ||
+		/* Note: packet_read_pending() might be slow if we have
+		 * to call it as it's per_cpu variable, but in fast-path
+		 * we already short-circuit the loop with the first
+		 * condition, and luckily don't have to go that path
+		 * anyway.
+		 */
+		 (need_wait && packet_read_pending(&po->tx_ring))));
+
+	err = len_sum;
+	goto out_put;
+
+out_status:
+	__packet_set_status(po, ph, status);
+	kfree_skb(skb);
+out_put:
+	dev_put(dev);
+out:
+	mutex_unlock(&po->pg_vec_lock);
+	return err;
+}
+
+static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,
+				        size_t reserve, size_t len,
+				        size_t linear, int noblock,
+				        int *err)
+{
+	struct sk_buff *skb;
+
+	/* Under a page?  Don't bother with paged skb. */
+	if (prepad + len < PAGE_SIZE || !linear)
+		linear = len;
+
+	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
+				   err, 0);
+	if (!skb)
+		return NULL;
+
+	skb_reserve(skb, reserve);
+	skb_put(skb, linear);
+	skb->data_len = len - linear;
+	skb->len += len - linear;
+
+	return skb;
+}
+
+static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	struct sock *sk = sock->sk;
+	DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
+	struct sk_buff *skb;
+	struct net_device *dev;
+	__be16 proto;
+	unsigned char *addr;
+	int err, reserve = 0;
+	struct virtio_net_hdr vnet_hdr = { 0 };
+	int offset = 0;
+	int vnet_hdr_len;
+	struct packet_sock *po = pkt_sk(sk);
+	unsigned short gso_type = 0;
+	int hlen, tlen;
+	int extra_len = 0;
+	ssize_t n;
+
+	/*
+	 *	Get and verify the address.
+	 */
+
+	if (likely(saddr == NULL)) {
+		dev	= packet_cached_dev_get(po);
+		proto	= po->num;
+		addr	= NULL;
+	} else {
+		err = -EINVAL;
+		if (msg->msg_namelen < sizeof(struct sockaddr_ll))
+			goto out;
+		if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
+			goto out;
+		proto	= saddr->sll_protocol;
+		addr	= saddr->sll_addr;
+		dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
+	}
+
+	err = -ENXIO;
+	if (unlikely(dev == NULL))
+		goto out_unlock;
+	err = -ENETDOWN;
+	if (unlikely(!(dev->flags & IFF_UP)))
+		goto out_unlock;
+
+	if (sock->type == SOCK_RAW)
+		reserve = dev->hard_header_len;
+	if (po->has_vnet_hdr) {
+		vnet_hdr_len = sizeof(vnet_hdr);
+
+		err = -EINVAL;
+		if (len < vnet_hdr_len)
+			goto out_unlock;
+
+		len -= vnet_hdr_len;
+
+		err = -EFAULT;
+		n = copy_from_iter(&vnet_hdr, vnet_hdr_len, &msg->msg_iter);
+		if (n != vnet_hdr_len)
+			goto out_unlock;
+
+		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+		    (__virtio16_to_cpu(false, vnet_hdr.csum_start) +
+		     __virtio16_to_cpu(false, vnet_hdr.csum_offset) + 2 >
+		      __virtio16_to_cpu(false, vnet_hdr.hdr_len)))
+			vnet_hdr.hdr_len = __cpu_to_virtio16(false,
+				 __virtio16_to_cpu(false, vnet_hdr.csum_start) +
+				__virtio16_to_cpu(false, vnet_hdr.csum_offset) + 2);
+
+		err = -EINVAL;
+		if (__virtio16_to_cpu(false, vnet_hdr.hdr_len) > len)
+			goto out_unlock;
+
+		if (vnet_hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+			switch (vnet_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+			case VIRTIO_NET_HDR_GSO_TCPV4:
+				gso_type = SKB_GSO_TCPV4;
+				break;
+			case VIRTIO_NET_HDR_GSO_TCPV6:
+				gso_type = SKB_GSO_TCPV6;
+				break;
+			case VIRTIO_NET_HDR_GSO_UDP:
+				gso_type = SKB_GSO_UDP;
+				break;
+			default:
+				goto out_unlock;
+			}
+
+			if (vnet_hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
+				gso_type |= SKB_GSO_TCP_ECN;
+
+			if (vnet_hdr.gso_size == 0)
+				goto out_unlock;
+
+		}
+	}
+
+	if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
+		if (!netif_supports_nofcs(dev)) {
+			err = -EPROTONOSUPPORT;
+			goto out_unlock;
+		}
+		extra_len = 4; /* We're doing our own CRC */
+	}
+
+	err = -EMSGSIZE;
+	if (!gso_type && (len > dev->mtu + reserve + VLAN_HLEN + extra_len))
+		goto out_unlock;
+
+	err = -ENOBUFS;
+	hlen = LL_RESERVED_SPACE(dev);
+	tlen = dev->needed_tailroom;
+	skb = packet_alloc_skb(sk, hlen + tlen, hlen, len,
+			       __virtio16_to_cpu(false, vnet_hdr.hdr_len),
+			       msg->msg_flags & MSG_DONTWAIT, &err);
+	if (skb == NULL)
+		goto out_unlock;
+
+	skb_set_network_header(skb, reserve);
+
+	err = -EINVAL;
+	if (sock->type == SOCK_DGRAM) {
+		offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);
+		if (unlikely(offset < 0))
+			goto out_free;
+	} else {
+		if (ll_header_truncated(dev, len))
+			goto out_free;
+	}
+
+	/* Returns -EFAULT on error */
+	err = skb_copy_datagram_from_iter(skb, offset, &msg->msg_iter, len);
+	if (err)
+		goto out_free;
+
+	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
+
+	if (!gso_type && (len > dev->mtu + reserve + extra_len)) {
+		/* Earlier code assumed this would be a VLAN pkt,
+		 * double-check this now that we have the actual
+		 * packet in hand.
+		 */
+		struct ethhdr *ehdr;
+		skb_reset_mac_header(skb);
+		ehdr = eth_hdr(skb);
+		if (ehdr->h_proto != htons(ETH_P_8021Q)) {
+			err = -EMSGSIZE;
+			goto out_free;
+		}
+	}
+
+	skb->protocol = proto;
+	skb->dev = dev;
+	skb->priority = sk->sk_priority;
+	skb->mark = sk->sk_mark;
+
+	packet_pick_tx_queue(dev, skb);
+
+	if (po->has_vnet_hdr) {
+		if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+			u16 s = __virtio16_to_cpu(false, vnet_hdr.csum_start);
+			u16 o = __virtio16_to_cpu(false, vnet_hdr.csum_offset);
+			if (!skb_partial_csum_set(skb, s, o)) {
+				err = -EINVAL;
+				goto out_free;
+			}
+		}
+
+		skb_shinfo(skb)->gso_size =
+			__virtio16_to_cpu(false, vnet_hdr.gso_size);
+		skb_shinfo(skb)->gso_type = gso_type;
+
+		/* Header must be checked, and gso_segs computed. */
+		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+		skb_shinfo(skb)->gso_segs = 0;
+
+		len += vnet_hdr_len;
+	}
+
+	if (!packet_use_direct_xmit(po))
+		skb_probe_transport_header(skb, reserve);
+	if (unlikely(extra_len == 4))
+		skb->no_fcs = 1;
+
+	err = po->xmit(skb);
+	if (err > 0 && (err = net_xmit_errno(err)) != 0)
+		goto out_unlock;
+
+	dev_put(dev);
+
+	return len;
+
+out_free:
+	kfree_skb(skb);
+out_unlock:
+	if (dev)
+		dev_put(dev);
+out:
+	return err;
+}
+
+static int packet_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+
+	if (po->tx_ring.pg_vec)
+		return tpacket_snd(po, msg);
+	else
+		return packet_snd(sock, msg, len);
+}
+
+/*
+ *	Close a PACKET socket. This is fairly simple. We immediately go
+ *	to 'closed' state and remove our protocol entry in the device list.
+ */
+
+static int packet_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct packet_sock *po;
+	struct net *net;
+	union tpacket_req_u req_u;
+
+	if (!sk)
+		return 0;
+
+	net = sock_net(sk);
+	po = pkt_sk(sk);
+
+	mutex_lock(&net->packet.sklist_lock);
+	sk_del_node_init_rcu(sk);
+	mutex_unlock(&net->packet.sklist_lock);
+
+	preempt_disable();
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
+	preempt_enable();
+
+	spin_lock(&po->bind_lock);
+	unregister_prot_hook(sk, false);
+	packet_cached_dev_reset(po);
+
+	if (po->prot_hook.dev) {
+		dev_put(po->prot_hook.dev);
+		po->prot_hook.dev = NULL;
+	}
+	spin_unlock(&po->bind_lock);
+
+	packet_flush_mclist(sk);
+
+	if (po->rx_ring.pg_vec) {
+		memset(&req_u, 0, sizeof(req_u));
+		packet_set_ring(sk, &req_u, 1, 0);
+	}
+
+	if (po->tx_ring.pg_vec) {
+		memset(&req_u, 0, sizeof(req_u));
+		packet_set_ring(sk, &req_u, 1, 1);
+	}
+
+	fanout_release(sk);
+
+	synchronize_net();
+	/*
+	 *	Now the socket is dead. No more input will appear.
+	 */
+	sock_orphan(sk);
+	sock->sk = NULL;
+
+	/* Purge queues */
+
+	skb_queue_purge(&sk->sk_receive_queue);
+	packet_free_pending(po);
+	sk_refcnt_debug_release(sk);
+
+	sock_put(sk);
+	return 0;
+}
+
+/*
+ *	Attach a packet hook.
+ */
+
+static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 proto)
+{
+	struct packet_sock *po = pkt_sk(sk);
+	const struct net_device *dev_curr;
+	__be16 proto_curr;
+	bool need_rehook;
+
+	if (po->fanout) {
+		if (dev)
+			dev_put(dev);
+
+		return -EINVAL;
+	}
+
+	lock_sock(sk);
+	spin_lock(&po->bind_lock);
+
+	proto_curr = po->prot_hook.type;
+	dev_curr = po->prot_hook.dev;
+
+	need_rehook = proto_curr != proto || dev_curr != dev;
+
+	if (need_rehook) {
+		unregister_prot_hook(sk, true);
+
+		po->num = proto;
+		po->prot_hook.type = proto;
+
+		if (po->prot_hook.dev)
+			dev_put(po->prot_hook.dev);
+
+		po->prot_hook.dev = dev;
+
+		po->ifindex = dev ? dev->ifindex : 0;
+		packet_cached_dev_assign(po, dev);
+	}
+
+	if (proto == 0 || !need_rehook)
+		goto out_unlock;
+
+	if (!dev || (dev->flags & IFF_UP)) {
+		register_prot_hook(sk);
+	} else {
+		sk->sk_err = ENETDOWN;
+		if (!sock_flag(sk, SOCK_DEAD))
+			sk->sk_error_report(sk);
+	}
+
+out_unlock:
+	spin_unlock(&po->bind_lock);
+	release_sock(sk);
+	return 0;
+}
+
+/*
+ *	Bind a packet socket to a device
+ */
+
+static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
+			    int addr_len)
+{
+	struct sock *sk = sock->sk;
+	char name[15];
+	struct net_device *dev;
+	int err = -ENODEV;
+
+	/*
+	 *	Check legality
+	 */
+
+	if (addr_len != sizeof(struct sockaddr))
+		return -EINVAL;
+	strlcpy(name, uaddr->sa_data, sizeof(name));
+
+	dev = dev_get_by_name(sock_net(sk), name);
+	if (dev)
+		err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
+	return err;
+}
+
+static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sockaddr_ll *sll = (struct sockaddr_ll *)uaddr;
+	struct sock *sk = sock->sk;
+	struct net_device *dev = NULL;
+	int err;
+
+
+	/*
+	 *	Check legality
+	 */
+
+	if (addr_len < sizeof(struct sockaddr_ll))
+		return -EINVAL;
+	if (sll->sll_family != AF_PACKET)
+		return -EINVAL;
+
+	if (sll->sll_ifindex) {
+		err = -ENODEV;
+		dev = dev_get_by_index(sock_net(sk), sll->sll_ifindex);
+		if (dev == NULL)
+			goto out;
+	}
+	err = packet_do_bind(sk, dev, sll->sll_protocol ? : pkt_sk(sk)->num);
+
+out:
+	return err;
+}
+
+static struct proto packet_proto = {
+	.name	  = "PACKET",
+	.owner	  = THIS_MODULE,
+	.obj_size = sizeof(struct packet_sock),
+};
+
+/*
+ *	Create a packet of type SOCK_PACKET.
+ */
+
+static int packet_create(struct net *net, struct socket *sock, int protocol,
+			 int kern)
+{
+	struct sock *sk;
+	struct packet_sock *po;
+	__be16 proto = (__force __be16)protocol; /* weird, but documented */
+	int err;
+
+	if (!ns_capable(net->user_ns, CAP_NET_RAW))
+		return -EPERM;
+	if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
+	    sock->type != SOCK_PACKET)
+		return -ESOCKTNOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+
+	err = -ENOBUFS;
+	sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto);
+	if (sk == NULL)
+		goto out;
+
+	sock->ops = &packet_ops;
+	if (sock->type == SOCK_PACKET)
+		sock->ops = &packet_ops_spkt;
+
+	sock_init_data(sock, sk);
+
+	po = pkt_sk(sk);
+	sk->sk_family = PF_PACKET;
+	po->num = proto;
+	po->xmit = dev_queue_xmit;
+
+	err = packet_alloc_pending(po);
+	if (err)
+		goto out2;
+
+	packet_cached_dev_reset(po);
+
+	sk->sk_destruct = packet_sock_destruct;
+	sk_refcnt_debug_inc(sk);
+
+	/*
+	 *	Attach a protocol block
+	 */
+
+	spin_lock_init(&po->bind_lock);
+	mutex_init(&po->pg_vec_lock);
+	po->prot_hook.func = packet_rcv;
+
+	if (sock->type == SOCK_PACKET)
+		po->prot_hook.func = packet_rcv_spkt;
+
+	po->prot_hook.af_packet_priv = sk;
+
+	if (proto) {
+		po->prot_hook.type = proto;
+		register_prot_hook(sk);
+	}
+
+	mutex_lock(&net->packet.sklist_lock);
+	sk_add_node_rcu(sk, &net->packet.sklist);
+	mutex_unlock(&net->packet.sklist_lock);
+
+	preempt_disable();
+	sock_prot_inuse_add(net, &packet_proto, 1);
+	preempt_enable();
+
+	return 0;
+out2:
+	sk_free(sk);
+out:
+	return err;
+}
+
+/*
+ *	Pull a packet from our receive queue and hand it to the user.
+ *	If necessary we block.
+ */
+
+static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+			  int flags)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	int copied, err;
+	int vnet_hdr_len = 0;
+	unsigned int origlen = 0;
+
+	err = -EINVAL;
+	if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT|MSG_ERRQUEUE))
+		goto out;
+
+#if 0
+	/* What error should we return now? EUNATTACH? */
+	if (pkt_sk(sk)->ifindex < 0)
+		return -ENODEV;
+#endif
+
+	if (flags & MSG_ERRQUEUE) {
+		err = sock_recv_errqueue(sk, msg, len,
+					 SOL_PACKET, PACKET_TX_TIMESTAMP);
+		goto out;
+	}
+
+	/*
+	 *	Call the generic datagram receiver. This handles all sorts
+	 *	of horrible races and re-entrancy so we can forget about it
+	 *	in the protocol layers.
+	 *
+	 *	Now it will return ENETDOWN, if device have just gone down,
+	 *	but then it will block.
+	 */
+
+	skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
+
+	/*
+	 *	An error occurred so return it. Because skb_recv_datagram()
+	 *	handles the blocking we don't see and worry about blocking
+	 *	retries.
+	 */
+
+	if (skb == NULL)
+		goto out;
+
+	if (pkt_sk(sk)->has_vnet_hdr) {
+		struct virtio_net_hdr vnet_hdr = { 0 };
+
+		err = -EINVAL;
+		vnet_hdr_len = sizeof(vnet_hdr);
+		if (len < vnet_hdr_len)
+			goto out_free;
+
+		len -= vnet_hdr_len;
+
+		if (skb_is_gso(skb)) {
+			struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+			/* This is a hint as to how much should be linear. */
+			vnet_hdr.hdr_len =
+				__cpu_to_virtio16(false, skb_headlen(skb));
+			vnet_hdr.gso_size =
+				__cpu_to_virtio16(false, sinfo->gso_size);
+			if (sinfo->gso_type & SKB_GSO_TCPV4)
+				vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+			else if (sinfo->gso_type & SKB_GSO_TCPV6)
+				vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+			else if (sinfo->gso_type & SKB_GSO_UDP)
+				vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
+			else if (sinfo->gso_type & SKB_GSO_FCOE)
+				goto out_free;
+			else
+				BUG();
+			if (sinfo->gso_type & SKB_GSO_TCP_ECN)
+				vnet_hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+		} else
+			vnet_hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+		if (skb->ip_summed == CHECKSUM_PARTIAL) {
+			vnet_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+			vnet_hdr.csum_start = __cpu_to_virtio16(false,
+					  skb_checksum_start_offset(skb));
+			vnet_hdr.csum_offset = __cpu_to_virtio16(false,
+							 skb->csum_offset);
+		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
+			vnet_hdr.flags = VIRTIO_NET_HDR_F_DATA_VALID;
+		} /* else everything is zero */
+
+		err = memcpy_to_msg(msg, (void *)&vnet_hdr, vnet_hdr_len);
+		if (err < 0)
+			goto out_free;
+	}
+
+	/* You lose any data beyond the buffer you gave. If it worries
+	 * a user program they can ask the device for its MTU
+	 * anyway.
+	 */
+	copied = skb->len;
+	if (copied > len) {
+		copied = len;
+		msg->msg_flags |= MSG_TRUNC;
+	}
+
+	err = skb_copy_datagram_msg(skb, 0, msg, copied);
+	if (err)
+		goto out_free;
+
+	if (sock->type != SOCK_PACKET) {
+		struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
+
+		/* Original length was stored in sockaddr_ll fields */
+		origlen = PACKET_SKB_CB(skb)->sa.origlen;
+		sll->sll_family = AF_PACKET;
+		sll->sll_protocol = skb->protocol;
+	}
+
+	sock_recv_ts_and_drops(msg, sk, skb);
+
+	if (msg->msg_name) {
+		/* If the address length field is there to be filled
+		 * in, we fill it in now.
+		 */
+		if (sock->type == SOCK_PACKET) {
+			__sockaddr_check_size(sizeof(struct sockaddr_pkt));
+			msg->msg_namelen = sizeof(struct sockaddr_pkt);
+		} else {
+			struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
+
+			msg->msg_namelen = sll->sll_halen +
+				offsetof(struct sockaddr_ll, sll_addr);
+		}
+		memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa,
+		       msg->msg_namelen);
+	}
+
+	if (pkt_sk(sk)->auxdata) {
+		struct tpacket_auxdata aux;
+
+		aux.tp_status = TP_STATUS_USER;
+		if (skb->ip_summed == CHECKSUM_PARTIAL)
+			aux.tp_status |= TP_STATUS_CSUMNOTREADY;
+		else if (skb->pkt_type != PACKET_OUTGOING &&
+			 (skb->ip_summed == CHECKSUM_COMPLETE ||
+			  skb_csum_unnecessary(skb)))
+			aux.tp_status |= TP_STATUS_CSUM_VALID;
+
+		aux.tp_len = origlen;
+		aux.tp_snaplen = skb->len;
+		aux.tp_mac = 0;
+		aux.tp_net = skb_network_offset(skb);
+		if (skb_vlan_tag_present(skb)) {
+			aux.tp_vlan_tci = skb_vlan_tag_get(skb);
+			aux.tp_vlan_tpid = ntohs(skb->vlan_proto);
+			aux.tp_status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
+		} else {
+			aux.tp_vlan_tci = 0;
+			aux.tp_vlan_tpid = 0;
+		}
+		put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
+	}
+
+	/*
+	 *	Free or return the buffer as appropriate. Again this
+	 *	hides all the races and re-entrancy issues from us.
+	 */
+	err = vnet_hdr_len + ((flags&MSG_TRUNC) ? skb->len : copied);
+
+out_free:
+	skb_free_datagram(sk, skb);
+out:
+	return err;
+}
+
+static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
+			       int *uaddr_len, int peer)
+{
+	struct net_device *dev;
+	struct sock *sk	= sock->sk;
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	uaddr->sa_family = AF_PACKET;
+	memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
+	rcu_read_lock();
+	dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
+	if (dev)
+		strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
+	rcu_read_unlock();
+	*uaddr_len = sizeof(*uaddr);
+
+	return 0;
+}
+
+static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
+			  int *uaddr_len, int peer)
+{
+	struct net_device *dev;
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+	DECLARE_SOCKADDR(struct sockaddr_ll *, sll, uaddr);
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	sll->sll_family = AF_PACKET;
+	sll->sll_ifindex = po->ifindex;
+	sll->sll_protocol = po->num;
+	sll->sll_pkttype = 0;
+	rcu_read_lock();
+	dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
+	if (dev) {
+		sll->sll_hatype = dev->type;
+		sll->sll_halen = dev->addr_len;
+		memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
+	} else {
+		sll->sll_hatype = 0;	/* Bad: we have no ARPHRD_UNSPEC */
+		sll->sll_halen = 0;
+	}
+	rcu_read_unlock();
+	*uaddr_len = offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
+
+	return 0;
+}
+
+static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
+			 int what)
+{
+	switch (i->type) {
+	case PACKET_MR_MULTICAST:
+		if (i->alen != dev->addr_len)
+			return -EINVAL;
+		if (what > 0)
+			return dev_mc_add(dev, i->addr);
+		else
+			return dev_mc_del(dev, i->addr);
+		break;
+	case PACKET_MR_PROMISC:
+		return dev_set_promiscuity(dev, what);
+	case PACKET_MR_ALLMULTI:
+		return dev_set_allmulti(dev, what);
+	case PACKET_MR_UNICAST:
+		if (i->alen != dev->addr_len)
+			return -EINVAL;
+		if (what > 0)
+			return dev_uc_add(dev, i->addr);
+		else
+			return dev_uc_del(dev, i->addr);
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static void packet_dev_mclist_delete(struct net_device *dev,
+				     struct packet_mclist **mlp)
+{
+	struct packet_mclist *ml;
+
+	while ((ml = *mlp) != NULL) {
+		if (ml->ifindex == dev->ifindex) {
+			packet_dev_mc(dev, ml, -1);
+			*mlp = ml->next;
+			kfree(ml);
+		} else
+			mlp = &ml->next;
+	}
+}
+
+static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
+{
+	struct packet_sock *po = pkt_sk(sk);
+	struct packet_mclist *ml, *i;
+	struct net_device *dev;
+	int err;
+
+	rtnl_lock();
+
+	err = -ENODEV;
+	dev = __dev_get_by_index(sock_net(sk), mreq->mr_ifindex);
+	if (!dev)
+		goto done;
+
+	err = -EINVAL;
+	if (mreq->mr_alen > dev->addr_len)
+		goto done;
+
+	err = -ENOBUFS;
+	i = kmalloc(sizeof(*i), GFP_KERNEL);
+	if (i == NULL)
+		goto done;
+
+	err = 0;
+	for (ml = po->mclist; ml; ml = ml->next) {
+		if (ml->ifindex == mreq->mr_ifindex &&
+		    ml->type == mreq->mr_type &&
+		    ml->alen == mreq->mr_alen &&
+		    memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
+			ml->count++;
+			/* Free the new element ... */
+			kfree(i);
+			goto done;
+		}
+	}
+
+	i->type = mreq->mr_type;
+	i->ifindex = mreq->mr_ifindex;
+	i->alen = mreq->mr_alen;
+	memcpy(i->addr, mreq->mr_address, i->alen);
+	i->count = 1;
+	i->next = po->mclist;
+	po->mclist = i;
+	err = packet_dev_mc(dev, i, 1);
+	if (err) {
+		po->mclist = i->next;
+		kfree(i);
+	}
+
+done:
+	rtnl_unlock();
+	return err;
+}
+
+static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
+{
+	struct packet_mclist *ml, **mlp;
+
+	rtnl_lock();
+
+	for (mlp = &pkt_sk(sk)->mclist; (ml = *mlp) != NULL; mlp = &ml->next) {
+		if (ml->ifindex == mreq->mr_ifindex &&
+		    ml->type == mreq->mr_type &&
+		    ml->alen == mreq->mr_alen &&
+		    memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
+			if (--ml->count == 0) {
+				struct net_device *dev;
+				*mlp = ml->next;
+				dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
+				if (dev)
+					packet_dev_mc(dev, ml, -1);
+				kfree(ml);
+			}
+			break;
+		}
+	}
+	rtnl_unlock();
+	return 0;
+}
+
+static void packet_flush_mclist(struct sock *sk)
+{
+	struct packet_sock *po = pkt_sk(sk);
+	struct packet_mclist *ml;
+
+	if (!po->mclist)
+		return;
+
+	rtnl_lock();
+	while ((ml = po->mclist) != NULL) {
+		struct net_device *dev;
+
+		po->mclist = ml->next;
+		dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
+		if (dev != NULL)
+			packet_dev_mc(dev, ml, -1);
+		kfree(ml);
+	}
+	rtnl_unlock();
+}
+
+static int
+packet_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+	int ret;
+
+	if (level != SOL_PACKET)
+		return -ENOPROTOOPT;
+
+	switch (optname) {
+	case PACKET_ADD_MEMBERSHIP:
+	case PACKET_DROP_MEMBERSHIP:
+	{
+		struct packet_mreq_max mreq;
+		int len = optlen;
+		memset(&mreq, 0, sizeof(mreq));
+		if (len < sizeof(struct packet_mreq))
+			return -EINVAL;
+		if (len > sizeof(mreq))
+			len = sizeof(mreq);
+		if (copy_from_user(&mreq, optval, len))
+			return -EFAULT;
+		if (len < (mreq.mr_alen + offsetof(struct packet_mreq, mr_address)))
+			return -EINVAL;
+		if (optname == PACKET_ADD_MEMBERSHIP)
+			ret = packet_mc_add(sk, &mreq);
+		else
+			ret = packet_mc_drop(sk, &mreq);
+		return ret;
+	}
+
+	case PACKET_RX_RING:
+	case PACKET_TX_RING:
+	{
+		union tpacket_req_u req_u;
+		int len;
+
+		switch (po->tp_version) {
+		case TPACKET_V1:
+		case TPACKET_V2:
+			len = sizeof(req_u.req);
+			break;
+		case TPACKET_V3:
+		default:
+			len = sizeof(req_u.req3);
+			break;
+		}
+		if (optlen < len)
+			return -EINVAL;
+		if (pkt_sk(sk)->has_vnet_hdr)
+			return -EINVAL;
+		if (copy_from_user(&req_u.req, optval, len))
+			return -EFAULT;
+		return packet_set_ring(sk, &req_u, 0,
+			optname == PACKET_TX_RING);
+	}
+	case PACKET_COPY_THRESH:
+	{
+		int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		pkt_sk(sk)->copy_thresh = val;
+		return 0;
+	}
+	case PACKET_VERSION:
+	{
+		int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
+			return -EBUSY;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+		switch (val) {
+		case TPACKET_V1:
+		case TPACKET_V2:
+		case TPACKET_V3:
+			po->tp_version = val;
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	}
+	case PACKET_RESERVE:
+	{
+		unsigned int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
+			return -EBUSY;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+		po->tp_reserve = val;
+		return 0;
+	}
+	case PACKET_LOSS:
+	{
+		unsigned int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
+			return -EBUSY;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+		po->tp_loss = !!val;
+		return 0;
+	}
+	case PACKET_AUXDATA:
+	{
+		int val;
+
+		if (optlen < sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		po->auxdata = !!val;
+		return 0;
+	}
+	case PACKET_ORIGDEV:
+	{
+		int val;
+
+		if (optlen < sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		po->origdev = !!val;
+		return 0;
+	}
+	case PACKET_VNET_HDR:
+	{
+		int val;
+
+		if (sock->type != SOCK_RAW)
+			return -EINVAL;
+		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
+			return -EBUSY;
+		if (optlen < sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		po->has_vnet_hdr = !!val;
+		return 0;
+	}
+	case PACKET_TIMESTAMP:
+	{
+		int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		po->tp_tstamp = val;
+		return 0;
+	}
+	case PACKET_FANOUT:
+	{
+		int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		return fanout_add(sk, val & 0xffff, val >> 16);
+	}
+	case PACKET_TX_HAS_OFF:
+	{
+		unsigned int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
+			return -EBUSY;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+		po->tp_tx_has_off = !!val;
+		return 0;
+	}
+	case PACKET_QDISC_BYPASS:
+	{
+		int val;
+
+		if (optlen != sizeof(val))
+			return -EINVAL;
+		if (copy_from_user(&val, optval, sizeof(val)))
+			return -EFAULT;
+
+		po->xmit = val ? packet_direct_xmit : dev_queue_xmit;
+		return 0;
+	}
+	default:
+		return -ENOPROTOOPT;
+	}
+}
+
+static int packet_getsockopt(struct socket *sock, int level, int optname,
+			     char __user *optval, int __user *optlen)
+{
+	int len;
+	int val, lv = sizeof(val);
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+	void *data = &val;
+	union tpacket_stats_u st;
+
+	if (level != SOL_PACKET)
+		return -ENOPROTOOPT;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	if (len < 0)
+		return -EINVAL;
+
+	switch (optname) {
+	case PACKET_STATISTICS:
+		spin_lock_bh(&sk->sk_receive_queue.lock);
+		memcpy(&st, &po->stats, sizeof(st));
+		memset(&po->stats, 0, sizeof(po->stats));
+		spin_unlock_bh(&sk->sk_receive_queue.lock);
+
+		if (po->tp_version == TPACKET_V3) {
+			lv = sizeof(struct tpacket_stats_v3);
+			st.stats3.tp_packets += st.stats3.tp_drops;
+			data = &st.stats3;
+		} else {
+			lv = sizeof(struct tpacket_stats);
+			st.stats1.tp_packets += st.stats1.tp_drops;
+			data = &st.stats1;
+		}
+
+		break;
+	case PACKET_AUXDATA:
+		val = po->auxdata;
+		break;
+	case PACKET_ORIGDEV:
+		val = po->origdev;
+		break;
+	case PACKET_VNET_HDR:
+		val = po->has_vnet_hdr;
+		break;
+	case PACKET_VERSION:
+		val = po->tp_version;
+		break;
+	case PACKET_HDRLEN:
+		if (len > sizeof(int))
+			len = sizeof(int);
+		if (copy_from_user(&val, optval, len))
+			return -EFAULT;
+		switch (val) {
+		case TPACKET_V1:
+			val = sizeof(struct tpacket_hdr);
+			break;
+		case TPACKET_V2:
+			val = sizeof(struct tpacket2_hdr);
+			break;
+		case TPACKET_V3:
+			val = sizeof(struct tpacket3_hdr);
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case PACKET_RESERVE:
+		val = po->tp_reserve;
+		break;
+	case PACKET_LOSS:
+		val = po->tp_loss;
+		break;
+	case PACKET_TIMESTAMP:
+		val = po->tp_tstamp;
+		break;
+	case PACKET_FANOUT:
+		val = (po->fanout ?
+		       ((u32)po->fanout->id |
+			((u32)po->fanout->type << 16) |
+			((u32)po->fanout->flags << 24)) :
+		       0);
+		break;
+	case PACKET_TX_HAS_OFF:
+		val = po->tp_tx_has_off;
+		break;
+	case PACKET_QDISC_BYPASS:
+		val = packet_use_direct_xmit(po);
+		break;
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (len > lv)
+		len = lv;
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, data, len))
+		return -EFAULT;
+	return 0;
+}
+
+
+static int packet_notifier(struct notifier_block *this,
+			   unsigned long msg, void *ptr)
+{
+	struct sock *sk;
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net *net = dev_net(dev);
+
+	rcu_read_lock();
+	sk_for_each_rcu(sk, &net->packet.sklist) {
+		struct packet_sock *po = pkt_sk(sk);
+
+		switch (msg) {
+		case NETDEV_UNREGISTER:
+			if (po->mclist)
+				packet_dev_mclist_delete(dev, &po->mclist);
+			/* fallthrough */
+
+		case NETDEV_DOWN:
+			if (dev->ifindex == po->ifindex) {
+				spin_lock(&po->bind_lock);
+				if (po->running) {
+					__unregister_prot_hook(sk, false);
+					sk->sk_err = ENETDOWN;
+					if (!sock_flag(sk, SOCK_DEAD))
+						sk->sk_error_report(sk);
+				}
+				if (msg == NETDEV_UNREGISTER) {
+					packet_cached_dev_reset(po);
+					po->ifindex = -1;
+					if (po->prot_hook.dev)
+						dev_put(po->prot_hook.dev);
+					po->prot_hook.dev = NULL;
+				}
+				spin_unlock(&po->bind_lock);
+			}
+			break;
+		case NETDEV_UP:
+			if (dev->ifindex == po->ifindex) {
+				spin_lock(&po->bind_lock);
+				if (po->num)
+					register_prot_hook(sk);
+				spin_unlock(&po->bind_lock);
+			}
+			break;
+		}
+	}
+	rcu_read_unlock();
+	return NOTIFY_DONE;
+}
+
+
+static int packet_ioctl(struct socket *sock, unsigned int cmd,
+			unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+
+	switch (cmd) {
+	case SIOCOUTQ:
+	{
+		int amount = sk_wmem_alloc_get(sk);
+
+		return put_user(amount, (int __user *)arg);
+	}
+	case SIOCINQ:
+	{
+		struct sk_buff *skb;
+		int amount = 0;
+
+		spin_lock_bh(&sk->sk_receive_queue.lock);
+		skb = skb_peek(&sk->sk_receive_queue);
+		if (skb)
+			amount = skb->len;
+		spin_unlock_bh(&sk->sk_receive_queue.lock);
+		return put_user(amount, (int __user *)arg);
+	}
+	case SIOCGSTAMP:
+		return sock_get_timestamp(sk, (struct timeval __user *)arg);
+	case SIOCGSTAMPNS:
+		return sock_get_timestampns(sk, (struct timespec __user *)arg);
+
+#ifdef CONFIG_INET
+	case SIOCADDRT:
+	case SIOCDELRT:
+	case SIOCDARP:
+	case SIOCGARP:
+	case SIOCSARP:
+	case SIOCGIFADDR:
+	case SIOCSIFADDR:
+	case SIOCGIFBRDADDR:
+	case SIOCSIFBRDADDR:
+	case SIOCGIFNETMASK:
+	case SIOCSIFNETMASK:
+	case SIOCGIFDSTADDR:
+	case SIOCSIFDSTADDR:
+	case SIOCSIFFLAGS:
+		return inet_dgram_ops.ioctl(sock, cmd, arg);
+#endif
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return 0;
+}
+
+static unsigned int packet_poll(struct file *file, struct socket *sock,
+				poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+	unsigned int mask = datagram_poll(file, sock, wait);
+
+	spin_lock_bh(&sk->sk_receive_queue.lock);
+	if (po->rx_ring.pg_vec) {
+		if (!packet_previous_rx_frame(po, &po->rx_ring,
+			TP_STATUS_KERNEL))
+			mask |= POLLIN | POLLRDNORM;
+	}
+	spin_unlock_bh(&sk->sk_receive_queue.lock);
+	spin_lock_bh(&sk->sk_write_queue.lock);
+	if (po->tx_ring.pg_vec) {
+		if (packet_current_frame(po, &po->tx_ring, TP_STATUS_AVAILABLE))
+			mask |= POLLOUT | POLLWRNORM;
+	}
+	spin_unlock_bh(&sk->sk_write_queue.lock);
+	return mask;
+}
+
+
+/* Dirty? Well, I still did not learn better way to account
+ * for user mmaps.
+ */
+
+static void packet_mm_open(struct vm_area_struct *vma)
+{
+	struct file *file = vma->vm_file;
+	struct socket *sock = file->private_data;
+	struct sock *sk = sock->sk;
+
+	if (sk)
+		atomic_inc(&pkt_sk(sk)->mapped);
+}
+
+static void packet_mm_close(struct vm_area_struct *vma)
+{
+	struct file *file = vma->vm_file;
+	struct socket *sock = file->private_data;
+	struct sock *sk = sock->sk;
+
+	if (sk)
+		atomic_dec(&pkt_sk(sk)->mapped);
+}
+
+static const struct vm_operations_struct packet_mmap_ops = {
+	.open	=	packet_mm_open,
+	.close	=	packet_mm_close,
+};
+
+static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
+			unsigned int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		if (likely(pg_vec[i].buffer)) {
+			if (is_vmalloc_addr(pg_vec[i].buffer))
+				vfree(pg_vec[i].buffer);
+			else
+				free_pages((unsigned long)pg_vec[i].buffer,
+					   order);
+			pg_vec[i].buffer = NULL;
+		}
+	}
+	kfree(pg_vec);
+}
+
+static char *alloc_one_pg_vec_page(unsigned long order)
+{
+	char *buffer;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
+			  __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
+
+	buffer = (char *) __get_free_pages(gfp_flags, order);
+	if (buffer)
+		return buffer;
+
+	/* __get_free_pages failed, fall back to vmalloc */
+	buffer = vzalloc((1 << order) * PAGE_SIZE);
+	if (buffer)
+		return buffer;
+
+	/* vmalloc failed, lets dig into swap here */
+	gfp_flags &= ~__GFP_NORETRY;
+	buffer = (char *) __get_free_pages(gfp_flags, order);
+	if (buffer)
+		return buffer;
+
+	/* complete and utter failure */
+	return NULL;
+}
+
+static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
+{
+	unsigned int block_nr = req->tp_block_nr;
+	struct pgv *pg_vec;
+	int i;
+
+	pg_vec = kcalloc(block_nr, sizeof(struct pgv), GFP_KERNEL);
+	if (unlikely(!pg_vec))
+		goto out;
+
+	for (i = 0; i < block_nr; i++) {
+		pg_vec[i].buffer = alloc_one_pg_vec_page(order);
+		if (unlikely(!pg_vec[i].buffer))
+			goto out_free_pgvec;
+	}
+
+out:
+	return pg_vec;
+
+out_free_pgvec:
+	free_pg_vec(pg_vec, order, block_nr);
+	pg_vec = NULL;
+	goto out;
+}
+
+static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
+		int closing, int tx_ring)
+{
+	struct pgv *pg_vec = NULL;
+	struct packet_sock *po = pkt_sk(sk);
+	int was_running, order = 0;
+	struct packet_ring_buffer *rb;
+	struct sk_buff_head *rb_queue;
+	__be16 num;
+	int err = -EINVAL;
+	/* Added to avoid minimal code churn */
+	struct tpacket_req *req = &req_u->req;
+
+	/* Opening a Tx-ring is NOT supported in TPACKET_V3 */
+	if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
+		WARN(1, "Tx-ring is not supported.\n");
+		goto out;
+	}
+
+	rb = tx_ring ? &po->tx_ring : &po->rx_ring;
+	rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
+
+	err = -EBUSY;
+	if (!closing) {
+		if (atomic_read(&po->mapped))
+			goto out;
+		if (packet_read_pending(rb))
+			goto out;
+	}
+
+	if (req->tp_block_nr) {
+		/* Sanity tests and some calculations */
+		err = -EBUSY;
+		if (unlikely(rb->pg_vec))
+			goto out;
+
+		switch (po->tp_version) {
+		case TPACKET_V1:
+			po->tp_hdrlen = TPACKET_HDRLEN;
+			break;
+		case TPACKET_V2:
+			po->tp_hdrlen = TPACKET2_HDRLEN;
+			break;
+		case TPACKET_V3:
+			po->tp_hdrlen = TPACKET3_HDRLEN;
+			break;
+		}
+
+		err = -EINVAL;
+		if (unlikely((int)req->tp_block_size <= 0))
+			goto out;
+		if (unlikely(req->tp_block_size & (PAGE_SIZE - 1)))
+			goto out;
+		if (po->tp_version >= TPACKET_V3 &&
+		    (int)(req->tp_block_size -
+			  BLK_PLUS_PRIV(req_u->req3.tp_sizeof_priv)) <= 0)
+			goto out;
+		if (unlikely(req->tp_frame_size < po->tp_hdrlen +
+					po->tp_reserve))
+			goto out;
+		if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
+			goto out;
+
+		rb->frames_per_block = req->tp_block_size/req->tp_frame_size;
+		if (unlikely(rb->frames_per_block <= 0))
+			goto out;
+		if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
+					req->tp_frame_nr))
+			goto out;
+
+		err = -ENOMEM;
+		order = get_order(req->tp_block_size);
+		pg_vec = alloc_pg_vec(req, order);
+		if (unlikely(!pg_vec))
+			goto out;
+		switch (po->tp_version) {
+		case TPACKET_V3:
+		/* Transmit path is not supported. We checked
+		 * it above but just being paranoid
+		 */
+			if (!tx_ring)
+				init_prb_bdqc(po, rb, pg_vec, req_u, tx_ring);
+			break;
+		default:
+			break;
+		}
+	}
+	/* Done */
+	else {
+		err = -EINVAL;
+		if (unlikely(req->tp_frame_nr))
+			goto out;
+	}
+
+	lock_sock(sk);
+
+	/* Detach socket from network */
+	spin_lock(&po->bind_lock);
+	was_running = po->running;
+	num = po->num;
+	if (was_running) {
+		po->num = 0;
+		__unregister_prot_hook(sk, false);
+	}
+	spin_unlock(&po->bind_lock);
+
+	synchronize_net();
+
+	err = -EBUSY;
+	mutex_lock(&po->pg_vec_lock);
+	if (closing || atomic_read(&po->mapped) == 0) {
+		err = 0;
+		spin_lock_bh(&rb_queue->lock);
+		swap(rb->pg_vec, pg_vec);
+		rb->frame_max = (req->tp_frame_nr - 1);
+		rb->head = 0;
+		rb->frame_size = req->tp_frame_size;
+		spin_unlock_bh(&rb_queue->lock);
+
+		swap(rb->pg_vec_order, order);
+		swap(rb->pg_vec_len, req->tp_block_nr);
+
+		rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
+		po->prot_hook.func = (po->rx_ring.pg_vec) ?
+						tpacket_rcv : packet_rcv;
+		skb_queue_purge(rb_queue);
+		if (atomic_read(&po->mapped))
+			pr_err("packet_mmap: vma is busy: %d\n",
+			       atomic_read(&po->mapped));
+	}
+	mutex_unlock(&po->pg_vec_lock);
+
+	spin_lock(&po->bind_lock);
+	if (was_running) {
+		po->num = num;
+		register_prot_hook(sk);
+	}
+	spin_unlock(&po->bind_lock);
+	if (closing && (po->tp_version > TPACKET_V2)) {
+		/* Because we don't support block-based V3 on tx-ring */
+		if (!tx_ring)
+			prb_shutdown_retire_blk_timer(po, tx_ring, rb_queue);
+	}
+	release_sock(sk);
+
+	if (pg_vec)
+		free_pg_vec(pg_vec, order, req->tp_block_nr);
+out:
+	return err;
+}
+
+static int packet_mmap(struct file *file, struct socket *sock,
+		struct vm_area_struct *vma)
+{
+	struct sock *sk = sock->sk;
+	struct packet_sock *po = pkt_sk(sk);
+	unsigned long size, expected_size;
+	struct packet_ring_buffer *rb;
+	unsigned long start;
+	int err = -EINVAL;
+	int i;
+
+	if (vma->vm_pgoff)
+		return -EINVAL;
+
+	mutex_lock(&po->pg_vec_lock);
+
+	expected_size = 0;
+	for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
+		if (rb->pg_vec) {
+			expected_size += rb->pg_vec_len
+						* rb->pg_vec_pages
+						* PAGE_SIZE;
+		}
+	}
+
+	if (expected_size == 0)
+		goto out;
+
+	size = vma->vm_end - vma->vm_start;
+	if (size != expected_size)
+		goto out;
+
+	start = vma->vm_start;
+	for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
+		if (rb->pg_vec == NULL)
+			continue;
+
+		for (i = 0; i < rb->pg_vec_len; i++) {
+			struct page *page;
+			void *kaddr = rb->pg_vec[i].buffer;
+			int pg_num;
+
+			for (pg_num = 0; pg_num < rb->pg_vec_pages; pg_num++) {
+				page = pgv_to_page(kaddr);
+				err = vm_insert_page(vma, start, page);
+				if (unlikely(err))
+					goto out;
+				start += PAGE_SIZE;
+				kaddr += PAGE_SIZE;
+			}
+		}
+	}
+
+	atomic_inc(&po->mapped);
+	vma->vm_ops = &packet_mmap_ops;
+	err = 0;
+
+out:
+	mutex_unlock(&po->pg_vec_lock);
+	return err;
+}
+
+static const struct proto_ops packet_ops_spkt = {
+	.family =	PF_PACKET,
+	.owner =	THIS_MODULE,
+	.release =	packet_release,
+	.bind =		packet_bind_spkt,
+	.connect =	sock_no_connect,
+	.socketpair =	sock_no_socketpair,
+	.accept =	sock_no_accept,
+	.getname =	packet_getname_spkt,
+	.poll =		datagram_poll,
+	.ioctl =	packet_ioctl,
+	.listen =	sock_no_listen,
+	.shutdown =	sock_no_shutdown,
+	.setsockopt =	sock_no_setsockopt,
+	.getsockopt =	sock_no_getsockopt,
+	.sendmsg =	packet_sendmsg_spkt,
+	.recvmsg =	packet_recvmsg,
+	.mmap =		sock_no_mmap,
+	.sendpage =	sock_no_sendpage,
+};
+
+static const struct proto_ops packet_ops = {
+	.family =	PF_PACKET,
+	.owner =	THIS_MODULE,
+	.release =	packet_release,
+	.bind =		packet_bind,
+	.connect =	sock_no_connect,
+	.socketpair =	sock_no_socketpair,
+	.accept =	sock_no_accept,
+	.getname =	packet_getname,
+	.poll =		packet_poll,
+	.ioctl =	packet_ioctl,
+	.listen =	sock_no_listen,
+	.shutdown =	sock_no_shutdown,
+	.setsockopt =	packet_setsockopt,
+	.getsockopt =	packet_getsockopt,
+	.sendmsg =	packet_sendmsg,
+	.recvmsg =	packet_recvmsg,
+	.mmap =		packet_mmap,
+	.sendpage =	sock_no_sendpage,
+};
+
+static const struct net_proto_family packet_family_ops = {
+	.family =	PF_PACKET,
+	.create =	packet_create,
+	.owner	=	THIS_MODULE,
+};
+
+static struct notifier_block packet_netdev_notifier = {
+	.notifier_call =	packet_notifier,
+};
+
+#ifdef CONFIG_PROC_FS
+
+static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	struct net *net = seq_file_net(seq);
+
+	rcu_read_lock();
+	return seq_hlist_start_head_rcu(&net->packet.sklist, *pos);
+}
+
+static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct net *net = seq_file_net(seq);
+	return seq_hlist_next_rcu(v, &net->packet.sklist, pos);
+}
+
+static void packet_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static int packet_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq, "sk       RefCnt Type Proto  Iface R Rmem   User   Inode\n");
+	else {
+		struct sock *s = sk_entry(v);
+		const struct packet_sock *po = pkt_sk(s);
+
+		seq_printf(seq,
+			   "%pK %-6d %-4d %04x   %-5d %1d %-6u %-6u %-6lu\n",
+			   s,
+			   atomic_read(&s->sk_refcnt),
+			   s->sk_type,
+			   ntohs(po->num),
+			   po->ifindex,
+			   po->running,
+			   atomic_read(&s->sk_rmem_alloc),
+			   from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
+			   sock_i_ino(s));
+	}
+
+	return 0;
+}
+
+static const struct seq_operations packet_seq_ops = {
+	.start	= packet_seq_start,
+	.next	= packet_seq_next,
+	.stop	= packet_seq_stop,
+	.show	= packet_seq_show,
+};
+
+static int packet_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open_net(inode, file, &packet_seq_ops,
+			    sizeof(struct seq_net_private));
+}
+
+static const struct file_operations packet_seq_fops = {
+	.owner		= THIS_MODULE,
+	.open		= packet_seq_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release_net,
+};
+
+#endif
+
+static int __net_init packet_net_init(struct net *net)
+{
+	mutex_init(&net->packet.sklist_lock);
+	INIT_HLIST_HEAD(&net->packet.sklist);
+
+	if (!proc_create("packet", 0, net->proc_net, &packet_seq_fops))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __net_exit packet_net_exit(struct net *net)
+{
+	remove_proc_entry("packet", net->proc_net);
+}
+
+static struct pernet_operations packet_net_ops = {
+	.init = packet_net_init,
+	.exit = packet_net_exit,
+};
+
+
+static void __exit packet_exit(void)
+{
+	unregister_netdevice_notifier(&packet_netdev_notifier);
+	unregister_pernet_subsys(&packet_net_ops);
+	sock_unregister(PF_PACKET);
+	proto_unregister(&packet_proto);
+}
+
+static int __init packet_init(void)
+{
+	int rc = proto_register(&packet_proto, 0);
+
+	if (rc != 0)
+		goto out;
+
+	sock_register(&packet_family_ops);
+	register_pernet_subsys(&packet_net_ops);
+	register_netdevice_notifier(&packet_netdev_notifier);
+out:
+	return rc;
+}
+
+module_init(packet_init);
+module_exit(packet_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_PACKET);