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linux/drivers/net/tun.c
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement 
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00

3444 lines
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/*
* TUN - Universal TUN/TAP device driver.
* Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
*/
/*
* Changes:
*
* Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
* Add TUNSETLINK ioctl to set the link encapsulation
*
* Mark Smith <markzzzsmith@yahoo.com.au>
* Use eth_random_addr() for tap MAC address.
*
* Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20
* Fixes in packet dropping, queue length setting and queue wakeup.
* Increased default tx queue length.
* Added ethtool API.
* Minor cleanups
*
* Daniel Podlejski <underley@underley.eu.org>
* Modifications for 2.3.99-pre5 kernel.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#define DRV_NAME "tun"
#define DRV_VERSION "1.6"
#define DRV_DESCRIPTION "Universal TUN/TAP device driver"
#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/miscdevice.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
#include <linux/compat.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/if_vlan.h>
#include <linux/crc32.h>
#include <linux/nsproxy.h>
#include <linux/virtio_net.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
#include <linux/seq_file.h>
#include <linux/uio.h>
#include <linux/skb_array.h>
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
/* Uncomment to enable debugging */
/* #define TUN_DEBUG 1 */
#ifdef TUN_DEBUG
static int debug;
#define tun_debug(level, tun, fmt, args...) \
do { \
if (tun->debug) \
netdev_printk(level, tun->dev, fmt, ##args); \
} while (0)
#define DBG1(level, fmt, args...) \
do { \
if (debug == 2) \
printk(level fmt, ##args); \
} while (0)
#else
#define tun_debug(level, tun, fmt, args...) \
do { \
if (0) \
netdev_printk(level, tun->dev, fmt, ##args); \
} while (0)
#define DBG1(level, fmt, args...) \
do { \
if (0) \
printk(level fmt, ##args); \
} while (0)
#endif
#define TUN_HEADROOM 256
#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
/* TUN device flags */
/* IFF_ATTACH_QUEUE is never stored in device flags,
* overload it to mean fasync when stored there.
*/
#define TUN_FASYNC IFF_ATTACH_QUEUE
/* High bits in flags field are unused. */
#define TUN_VNET_LE 0x80000000
#define TUN_VNET_BE 0x40000000
#define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \
IFF_MULTI_QUEUE | IFF_NAPI | IFF_NAPI_FRAGS)
#define GOODCOPY_LEN 128
#define FLT_EXACT_COUNT 8
struct tap_filter {
unsigned int count; /* Number of addrs. Zero means disabled */
u32 mask[2]; /* Mask of the hashed addrs */
unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
};
/* MAX_TAP_QUEUES 256 is chosen to allow rx/tx queues to be equal
* to max number of VCPUs in guest. */
#define MAX_TAP_QUEUES 256
#define MAX_TAP_FLOWS 4096
#define TUN_FLOW_EXPIRE (3 * HZ)
struct tun_pcpu_stats {
u64 rx_packets;
u64 rx_bytes;
u64 tx_packets;
u64 tx_bytes;
struct u64_stats_sync syncp;
u32 rx_dropped;
u32 tx_dropped;
u32 rx_frame_errors;
};
/* A tun_file connects an open character device to a tuntap netdevice. It
* also contains all socket related structures (except sock_fprog and tap_filter)
* to serve as one transmit queue for tuntap device. The sock_fprog and
* tap_filter were kept in tun_struct since they were used for filtering for the
* netdevice not for a specific queue (at least I didn't see the requirement for
* this).
*
* RCU usage:
* The tun_file and tun_struct are loosely coupled, the pointer from one to the
* other can only be read while rcu_read_lock or rtnl_lock is held.
*/
struct tun_file {
struct sock sk;
struct socket socket;
struct socket_wq wq;
struct tun_struct __rcu *tun;
struct fasync_struct *fasync;
/* only used for fasnyc */
unsigned int flags;
union {
u16 queue_index;
unsigned int ifindex;
};
struct napi_struct napi;
bool napi_enabled;
struct mutex napi_mutex; /* Protects access to the above napi */
struct list_head next;
struct tun_struct *detached;
struct ptr_ring tx_ring;
struct xdp_rxq_info xdp_rxq;
int xdp_pending_pkts;
};
struct tun_flow_entry {
struct hlist_node hash_link;
struct rcu_head rcu;
struct tun_struct *tun;
u32 rxhash;
u32 rps_rxhash;
int queue_index;
unsigned long updated;
};
#define TUN_NUM_FLOW_ENTRIES 1024
struct tun_prog {
struct rcu_head rcu;
struct bpf_prog *prog;
};
/* Since the socket were moved to tun_file, to preserve the behavior of persist
* device, socket filter, sndbuf and vnet header size were restore when the
* file were attached to a persist device.
*/
struct tun_struct {
struct tun_file __rcu *tfiles[MAX_TAP_QUEUES];
unsigned int numqueues;
unsigned int flags;
kuid_t owner;
kgid_t group;
struct net_device *dev;
netdev_features_t set_features;
#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
NETIF_F_TSO6)
int align;
int vnet_hdr_sz;
int sndbuf;
struct tap_filter txflt;
struct sock_fprog fprog;
/* protected by rtnl lock */
bool filter_attached;
#ifdef TUN_DEBUG
int debug;
#endif
spinlock_t lock;
struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
struct timer_list flow_gc_timer;
unsigned long ageing_time;
unsigned int numdisabled;
struct list_head disabled;
void *security;
u32 flow_count;
u32 rx_batched;
struct tun_pcpu_stats __percpu *pcpu_stats;
struct bpf_prog __rcu *xdp_prog;
struct tun_prog __rcu *steering_prog;
struct tun_prog __rcu *filter_prog;
};
struct veth {
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
};
bool tun_is_xdp_buff(void *ptr)
{
return (unsigned long)ptr & TUN_XDP_FLAG;
}
EXPORT_SYMBOL(tun_is_xdp_buff);
void *tun_xdp_to_ptr(void *ptr)
{
return (void *)((unsigned long)ptr | TUN_XDP_FLAG);
}
EXPORT_SYMBOL(tun_xdp_to_ptr);
void *tun_ptr_to_xdp(void *ptr)
{
return (void *)((unsigned long)ptr & ~TUN_XDP_FLAG);
}
EXPORT_SYMBOL(tun_ptr_to_xdp);
static int tun_napi_receive(struct napi_struct *napi, int budget)
{
struct tun_file *tfile = container_of(napi, struct tun_file, napi);
struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
struct sk_buff_head process_queue;
struct sk_buff *skb;
int received = 0;
__skb_queue_head_init(&process_queue);
spin_lock(&queue->lock);
skb_queue_splice_tail_init(queue, &process_queue);
spin_unlock(&queue->lock);
while (received < budget && (skb = __skb_dequeue(&process_queue))) {
napi_gro_receive(napi, skb);
++received;
}
if (!skb_queue_empty(&process_queue)) {
spin_lock(&queue->lock);
skb_queue_splice(&process_queue, queue);
spin_unlock(&queue->lock);
}
return received;
}
static int tun_napi_poll(struct napi_struct *napi, int budget)
{
unsigned int received;
received = tun_napi_receive(napi, budget);
if (received < budget)
napi_complete_done(napi, received);
return received;
}
static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
bool napi_en)
{
tfile->napi_enabled = napi_en;
if (napi_en) {
netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
NAPI_POLL_WEIGHT);
napi_enable(&tfile->napi);
mutex_init(&tfile->napi_mutex);
}
}
static void tun_napi_disable(struct tun_struct *tun, struct tun_file *tfile)
{
if (tfile->napi_enabled)
napi_disable(&tfile->napi);
}
static void tun_napi_del(struct tun_struct *tun, struct tun_file *tfile)
{
if (tfile->napi_enabled)
netif_napi_del(&tfile->napi);
}
static bool tun_napi_frags_enabled(const struct tun_struct *tun)
{
return READ_ONCE(tun->flags) & IFF_NAPI_FRAGS;
}
#ifdef CONFIG_TUN_VNET_CROSS_LE
static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
{
return tun->flags & TUN_VNET_BE ? false :
virtio_legacy_is_little_endian();
}
static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
{
int be = !!(tun->flags & TUN_VNET_BE);
if (put_user(be, argp))
return -EFAULT;
return 0;
}
static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
{
int be;
if (get_user(be, argp))
return -EFAULT;
if (be)
tun->flags |= TUN_VNET_BE;
else
tun->flags &= ~TUN_VNET_BE;
return 0;
}
#else
static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
{
return virtio_legacy_is_little_endian();
}
static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
{
return -EINVAL;
}
static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
{
return -EINVAL;
}
#endif /* CONFIG_TUN_VNET_CROSS_LE */
static inline bool tun_is_little_endian(struct tun_struct *tun)
{
return tun->flags & TUN_VNET_LE ||
tun_legacy_is_little_endian(tun);
}
static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
{
return __virtio16_to_cpu(tun_is_little_endian(tun), val);
}
static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
{
return __cpu_to_virtio16(tun_is_little_endian(tun), val);
}
static inline u32 tun_hashfn(u32 rxhash)
{
return rxhash & 0x3ff;
}
static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash)
{
struct tun_flow_entry *e;
hlist_for_each_entry_rcu(e, head, hash_link) {
if (e->rxhash == rxhash)
return e;
}
return NULL;
}
static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
struct hlist_head *head,
u32 rxhash, u16 queue_index)
{
struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);
if (e) {
tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
rxhash, queue_index);
e->updated = jiffies;
e->rxhash = rxhash;
e->rps_rxhash = 0;
e->queue_index = queue_index;
e->tun = tun;
hlist_add_head_rcu(&e->hash_link, head);
++tun->flow_count;
}
return e;
}
static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
{
tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
e->rxhash, e->queue_index);
hlist_del_rcu(&e->hash_link);
kfree_rcu(e, rcu);
--tun->flow_count;
}
static void tun_flow_flush(struct tun_struct *tun)
{
int i;
spin_lock_bh(&tun->lock);
for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
struct tun_flow_entry *e;
struct hlist_node *n;
hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link)
tun_flow_delete(tun, e);
}
spin_unlock_bh(&tun->lock);
}
static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index)
{
int i;
spin_lock_bh(&tun->lock);
for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
struct tun_flow_entry *e;
struct hlist_node *n;
hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
if (e->queue_index == queue_index)
tun_flow_delete(tun, e);
}
}
spin_unlock_bh(&tun->lock);
}
static void tun_flow_cleanup(struct timer_list *t)
{
struct tun_struct *tun = from_timer(tun, t, flow_gc_timer);
unsigned long delay = tun->ageing_time;
unsigned long next_timer = jiffies + delay;
unsigned long count = 0;
int i;
tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");
spin_lock(&tun->lock);
for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
struct tun_flow_entry *e;
struct hlist_node *n;
hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) {
unsigned long this_timer;
this_timer = e->updated + delay;
if (time_before_eq(this_timer, jiffies)) {
tun_flow_delete(tun, e);
continue;
}
count++;
if (time_before(this_timer, next_timer))
next_timer = this_timer;
}
}
if (count)
mod_timer(&tun->flow_gc_timer, round_jiffies_up(next_timer));
spin_unlock(&tun->lock);
}
static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
struct tun_file *tfile)
{
struct hlist_head *head;
struct tun_flow_entry *e;
unsigned long delay = tun->ageing_time;
u16 queue_index = tfile->queue_index;
if (!rxhash)
return;
else
head = &tun->flows[tun_hashfn(rxhash)];
rcu_read_lock();
/* We may get a very small possibility of OOO during switching, not
* worth to optimize.*/
if (tun->numqueues == 1 || tfile->detached)
goto unlock;
e = tun_flow_find(head, rxhash);
if (likely(e)) {
/* TODO: keep queueing to old queue until it's empty? */
e->queue_index = queue_index;
e->updated = jiffies;
sock_rps_record_flow_hash(e->rps_rxhash);
} else {
spin_lock_bh(&tun->lock);
if (!tun_flow_find(head, rxhash) &&
tun->flow_count < MAX_TAP_FLOWS)
tun_flow_create(tun, head, rxhash, queue_index);
if (!timer_pending(&tun->flow_gc_timer))
mod_timer(&tun->flow_gc_timer,
round_jiffies_up(jiffies + delay));
spin_unlock_bh(&tun->lock);
}
unlock:
rcu_read_unlock();
}
/**
* Save the hash received in the stack receive path and update the
* flow_hash table accordingly.
*/
static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
{
if (unlikely(e->rps_rxhash != hash))
e->rps_rxhash = hash;
}
/* We try to identify a flow through its rxhash first. The reason that
* we do not check rxq no. is because some cards(e.g 82599), chooses
* the rxq based on the txq where the last packet of the flow comes. As
* the userspace application move between processors, we may get a
* different rxq no. here. If we could not get rxhash, then we would
* hope the rxq no. may help here.
*/
static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb)
{
struct tun_flow_entry *e;
u32 txq = 0;
u32 numqueues = 0;
numqueues = READ_ONCE(tun->numqueues);
txq = __skb_get_hash_symmetric(skb);
if (txq) {
e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq);
if (e) {
tun_flow_save_rps_rxhash(e, txq);
txq = e->queue_index;
} else
/* use multiply and shift instead of expensive divide */
txq = ((u64)txq * numqueues) >> 32;
} else if (likely(skb_rx_queue_recorded(skb))) {
txq = skb_get_rx_queue(skb);
while (unlikely(txq >= numqueues))
txq -= numqueues;
}
return txq;
}
static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)
{
struct tun_prog *prog;
u16 ret = 0;
prog = rcu_dereference(tun->steering_prog);
if (prog)
ret = bpf_prog_run_clear_cb(prog->prog, skb);
return ret % tun->numqueues;
}
static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb,
void *accel_priv, select_queue_fallback_t fallback)
{
struct tun_struct *tun = netdev_priv(dev);
u16 ret;
rcu_read_lock();
if (rcu_dereference(tun->steering_prog))
ret = tun_ebpf_select_queue(tun, skb);
else
ret = tun_automq_select_queue(tun, skb);
rcu_read_unlock();
return ret;
}
static inline bool tun_not_capable(struct tun_struct *tun)
{
const struct cred *cred = current_cred();
struct net *net = dev_net(tun->dev);
return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) ||
(gid_valid(tun->group) && !in_egroup_p(tun->group))) &&
!ns_capable(net->user_ns, CAP_NET_ADMIN);
}
static void tun_set_real_num_queues(struct tun_struct *tun)
{
netif_set_real_num_tx_queues(tun->dev, tun->numqueues);
netif_set_real_num_rx_queues(tun->dev, tun->numqueues);
}
static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile)
{
tfile->detached = tun;
list_add_tail(&tfile->next, &tun->disabled);
++tun->numdisabled;
}
static struct tun_struct *tun_enable_queue(struct tun_file *tfile)
{
struct tun_struct *tun = tfile->detached;
tfile->detached = NULL;
list_del_init(&tfile->next);
--tun->numdisabled;
return tun;
}
static void tun_ptr_free(void *ptr)
{
if (!ptr)
return;
if (tun_is_xdp_buff(ptr)) {
struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
put_page(virt_to_head_page(xdp->data));
} else {
__skb_array_destroy_skb(ptr);
}
}
static void tun_queue_purge(struct tun_file *tfile)
{
void *ptr;
while ((ptr = ptr_ring_consume(&tfile->tx_ring)) != NULL)
tun_ptr_free(ptr);
skb_queue_purge(&tfile->sk.sk_write_queue);
skb_queue_purge(&tfile->sk.sk_error_queue);
}
static void tun_cleanup_tx_ring(struct tun_file *tfile)
{
if (tfile->tx_ring.queue) {
ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
xdp_rxq_info_unreg(&tfile->xdp_rxq);
memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
}
}
static void __tun_detach(struct tun_file *tfile, bool clean)
{
struct tun_file *ntfile;
struct tun_struct *tun;
tun = rtnl_dereference(tfile->tun);
if (tun && clean) {
tun_napi_disable(tun, tfile);
tun_napi_del(tun, tfile);
}
if (tun && !tfile->detached) {
u16 index = tfile->queue_index;
BUG_ON(index >= tun->numqueues);
rcu_assign_pointer(tun->tfiles[index],
tun->tfiles[tun->numqueues - 1]);
ntfile = rtnl_dereference(tun->tfiles[index]);
ntfile->queue_index = index;
--tun->numqueues;
if (clean) {
RCU_INIT_POINTER(tfile->tun, NULL);
sock_put(&tfile->sk);
} else
tun_disable_queue(tun, tfile);
synchronize_net();
tun_flow_delete_by_queue(tun, tun->numqueues + 1);
/* Drop read queue */
tun_queue_purge(tfile);
tun_set_real_num_queues(tun);
} else if (tfile->detached && clean) {
tun = tun_enable_queue(tfile);
sock_put(&tfile->sk);
}
if (clean) {
if (tun && tun->numqueues == 0 && tun->numdisabled == 0) {
netif_carrier_off(tun->dev);
if (!(tun->flags & IFF_PERSIST) &&
tun->dev->reg_state == NETREG_REGISTERED)
unregister_netdevice(tun->dev);
}
tun_cleanup_tx_ring(tfile);
sock_put(&tfile->sk);
}
}
static void tun_detach(struct tun_file *tfile, bool clean)
{
rtnl_lock();
__tun_detach(tfile, clean);
rtnl_unlock();
}
static void tun_detach_all(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
struct tun_file *tfile, *tmp;
int i, n = tun->numqueues;
for (i = 0; i < n; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
BUG_ON(!tfile);
tun_napi_disable(tun, tfile);
tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
tfile->socket.sk->sk_data_ready(tfile->socket.sk);
RCU_INIT_POINTER(tfile->tun, NULL);
--tun->numqueues;
}
list_for_each_entry(tfile, &tun->disabled, next) {
tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
tfile->socket.sk->sk_data_ready(tfile->socket.sk);
RCU_INIT_POINTER(tfile->tun, NULL);
}
BUG_ON(tun->numqueues != 0);
synchronize_net();
for (i = 0; i < n; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
tun_napi_del(tun, tfile);
/* Drop read queue */
tun_queue_purge(tfile);
sock_put(&tfile->sk);
tun_cleanup_tx_ring(tfile);
}
list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
tun_enable_queue(tfile);
tun_queue_purge(tfile);
sock_put(&tfile->sk);
tun_cleanup_tx_ring(tfile);
}
BUG_ON(tun->numdisabled != 0);
if (tun->flags & IFF_PERSIST)
module_put(THIS_MODULE);
}
static int tun_attach(struct tun_struct *tun, struct file *file,
bool skip_filter, bool napi)
{
struct tun_file *tfile = file->private_data;
struct net_device *dev = tun->dev;
int err;
err = security_tun_dev_attach(tfile->socket.sk, tun->security);
if (err < 0)
goto out;
err = -EINVAL;
if (rtnl_dereference(tfile->tun) && !tfile->detached)
goto out;
err = -EBUSY;
if (!(tun->flags & IFF_MULTI_QUEUE) && tun->numqueues == 1)
goto out;
err = -E2BIG;
if (!tfile->detached &&
tun->numqueues + tun->numdisabled == MAX_TAP_QUEUES)
goto out;
err = 0;
/* Re-attach the filter to persist device */
if (!skip_filter && (tun->filter_attached == true)) {
lock_sock(tfile->socket.sk);
err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
release_sock(tfile->socket.sk);
if (!err)
goto out;
}
if (!tfile->detached &&
ptr_ring_init(&tfile->tx_ring, dev->tx_queue_len, GFP_KERNEL)) {
err = -ENOMEM;
goto out;
}
tfile->queue_index = tun->numqueues;
tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
if (tfile->detached) {
/* Re-attach detached tfile, updating XDP queue_index */
WARN_ON(!xdp_rxq_info_is_reg(&tfile->xdp_rxq));
if (tfile->xdp_rxq.queue_index != tfile->queue_index)
tfile->xdp_rxq.queue_index = tfile->queue_index;
} else {
/* Setup XDP RX-queue info, for new tfile getting attached */
err = xdp_rxq_info_reg(&tfile->xdp_rxq,
tun->dev, tfile->queue_index);
if (err < 0)
goto out;
err = 0;
}
rcu_assign_pointer(tfile->tun, tun);
rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
tun->numqueues++;
if (tfile->detached) {
tun_enable_queue(tfile);
} else {
sock_hold(&tfile->sk);
tun_napi_init(tun, tfile, napi);
}
tun_set_real_num_queues(tun);
/* device is allowed to go away first, so no need to hold extra
* refcnt.
*/
out:
return err;
}
static struct tun_struct *tun_get(struct tun_file *tfile)
{
struct tun_struct *tun;
rcu_read_lock();
tun = rcu_dereference(tfile->tun);
if (tun)
dev_hold(tun->dev);
rcu_read_unlock();
return tun;
}
static void tun_put(struct tun_struct *tun)
{
dev_put(tun->dev);
}
/* TAP filtering */
static void addr_hash_set(u32 *mask, const u8 *addr)
{
int n = ether_crc(ETH_ALEN, addr) >> 26;
mask[n >> 5] |= (1 << (n & 31));
}
static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
{
int n = ether_crc(ETH_ALEN, addr) >> 26;
return mask[n >> 5] & (1 << (n & 31));
}
static int update_filter(struct tap_filter *filter, void __user *arg)
{
struct { u8 u[ETH_ALEN]; } *addr;
struct tun_filter uf;
int err, alen, n, nexact;
if (copy_from_user(&uf, arg, sizeof(uf)))
return -EFAULT;
if (!uf.count) {
/* Disabled */
filter->count = 0;
return 0;
}
alen = ETH_ALEN * uf.count;
addr = memdup_user(arg + sizeof(uf), alen);
if (IS_ERR(addr))
return PTR_ERR(addr);
/* The filter is updated without holding any locks. Which is
* perfectly safe. We disable it first and in the worst
* case we'll accept a few undesired packets. */
filter->count = 0;
wmb();
/* Use first set of addresses as an exact filter */
for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
nexact = n;
/* Remaining multicast addresses are hashed,
* unicast will leave the filter disabled. */
memset(filter->mask, 0, sizeof(filter->mask));
for (; n < uf.count; n++) {
if (!is_multicast_ether_addr(addr[n].u)) {
err = 0; /* no filter */
goto free_addr;
}
addr_hash_set(filter->mask, addr[n].u);
}
/* For ALLMULTI just set the mask to all ones.
* This overrides the mask populated above. */
if ((uf.flags & TUN_FLT_ALLMULTI))
memset(filter->mask, ~0, sizeof(filter->mask));
/* Now enable the filter */
wmb();
filter->count = nexact;
/* Return the number of exact filters */
err = nexact;
free_addr:
kfree(addr);
return err;
}
/* Returns: 0 - drop, !=0 - accept */
static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
{
/* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
* at this point. */
struct ethhdr *eh = (struct ethhdr *) skb->data;
int i;
/* Exact match */
for (i = 0; i < filter->count; i++)
if (ether_addr_equal(eh->h_dest, filter->addr[i]))
return 1;
/* Inexact match (multicast only) */
if (is_multicast_ether_addr(eh->h_dest))
return addr_hash_test(filter->mask, eh->h_dest);
return 0;
}
/*
* Checks whether the packet is accepted or not.
* Returns: 0 - drop, !=0 - accept
*/
static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
{
if (!filter->count)
return 1;
return run_filter(filter, skb);
}
/* Network device part of the driver */
static const struct ethtool_ops tun_ethtool_ops;
/* Net device detach from fd. */
static void tun_net_uninit(struct net_device *dev)
{
tun_detach_all(dev);
}
/* Net device open. */
static int tun_net_open(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
int i;
netif_tx_start_all_queues(dev);
for (i = 0; i < tun->numqueues; i++) {
struct tun_file *tfile;
tfile = rtnl_dereference(tun->tfiles[i]);
tfile->socket.sk->sk_write_space(tfile->socket.sk);
}
return 0;
}
/* Net device close. */
static int tun_net_close(struct net_device *dev)
{
netif_tx_stop_all_queues(dev);
return 0;
}
/* Net device start xmit */
static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb)
{
#ifdef CONFIG_RPS
if (tun->numqueues == 1 && static_key_false(&rps_needed)) {
/* Select queue was not called for the skbuff, so we extract the
* RPS hash and save it into the flow_table here.
*/
__u32 rxhash;
rxhash = __skb_get_hash_symmetric(skb);
if (rxhash) {
struct tun_flow_entry *e;
e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)],
rxhash);
if (e)
tun_flow_save_rps_rxhash(e, rxhash);
}
}
#endif
}
static unsigned int run_ebpf_filter(struct tun_struct *tun,
struct sk_buff *skb,
int len)
{
struct tun_prog *prog = rcu_dereference(tun->filter_prog);
if (prog)
len = bpf_prog_run_clear_cb(prog->prog, skb);
return len;
}
/* Net device start xmit */
static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
int txq = skb->queue_mapping;
struct tun_file *tfile;
int len = skb->len;
rcu_read_lock();
tfile = rcu_dereference(tun->tfiles[txq]);
/* Drop packet if interface is not attached */
if (txq >= tun->numqueues)
goto drop;
if (!rcu_dereference(tun->steering_prog))
tun_automq_xmit(tun, skb);
tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
BUG_ON(!tfile);
/* Drop if the filter does not like it.
* This is a noop if the filter is disabled.
* Filter can be enabled only for the TAP devices. */
if (!check_filter(&tun->txflt, skb))
goto drop;
if (tfile->socket.sk->sk_filter &&
sk_filter(tfile->socket.sk, skb))
goto drop;
len = run_ebpf_filter(tun, skb, len);
/* Trim extra bytes since we may insert vlan proto & TCI
* in tun_put_user().
*/
len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0;
if (len <= 0 || pskb_trim(skb, len))
goto drop;
if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
goto drop;
skb_tx_timestamp(skb);
/* Orphan the skb - required as we might hang on to it
* for indefinite time.
*/
skb_orphan(skb);
nf_reset(skb);
if (ptr_ring_produce(&tfile->tx_ring, skb))
goto drop;
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
tfile->socket.sk->sk_data_ready(tfile->socket.sk);
rcu_read_unlock();
return NETDEV_TX_OK;
drop:
this_cpu_inc(tun->pcpu_stats->tx_dropped);
skb_tx_error(skb);
kfree_skb(skb);
rcu_read_unlock();
return NET_XMIT_DROP;
}
static void tun_net_mclist(struct net_device *dev)
{
/*
* This callback is supposed to deal with mc filter in
* _rx_ path and has nothing to do with the _tx_ path.
* In rx path we always accept everything userspace gives us.
*/
}
static netdev_features_t tun_net_fix_features(struct net_device *dev,
netdev_features_t features)
{
struct tun_struct *tun = netdev_priv(dev);
return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
}
#ifdef CONFIG_NET_POLL_CONTROLLER
static void tun_poll_controller(struct net_device *dev)
{
/*
* Tun only receives frames when:
* 1) the char device endpoint gets data from user space
* 2) the tun socket gets a sendmsg call from user space
* If NAPI is not enabled, since both of those are synchronous
* operations, we are guaranteed never to have pending data when we poll
* for it so there is nothing to do here but return.
* We need this though so netpoll recognizes us as an interface that
* supports polling, which enables bridge devices in virt setups to
* still use netconsole
* If NAPI is enabled, however, we need to schedule polling for all
* queues unless we are using napi_gro_frags(), which we call in
* process context and not in NAPI context.
*/
struct tun_struct *tun = netdev_priv(dev);
if (tun->flags & IFF_NAPI) {
struct tun_file *tfile;
int i;
if (tun_napi_frags_enabled(tun))
return;
rcu_read_lock();
for (i = 0; i < tun->numqueues; i++) {
tfile = rcu_dereference(tun->tfiles[i]);
if (tfile->napi_enabled)
napi_schedule(&tfile->napi);
}
rcu_read_unlock();
}
return;
}
#endif
static void tun_set_headroom(struct net_device *dev, int new_hr)
{
struct tun_struct *tun = netdev_priv(dev);
if (new_hr < NET_SKB_PAD)
new_hr = NET_SKB_PAD;
tun->align = new_hr;
}
static void
tun_net_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
{
u32 rx_dropped = 0, tx_dropped = 0, rx_frame_errors = 0;
struct tun_struct *tun = netdev_priv(dev);
struct tun_pcpu_stats *p;
int i;
for_each_possible_cpu(i) {
u64 rxpackets, rxbytes, txpackets, txbytes;
unsigned int start;
p = per_cpu_ptr(tun->pcpu_stats, i);
do {
start = u64_stats_fetch_begin(&p->syncp);
rxpackets = p->rx_packets;
rxbytes = p->rx_bytes;
txpackets = p->tx_packets;
txbytes = p->tx_bytes;
} while (u64_stats_fetch_retry(&p->syncp, start));
stats->rx_packets += rxpackets;
stats->rx_bytes += rxbytes;
stats->tx_packets += txpackets;
stats->tx_bytes += txbytes;
/* u32 counters */
rx_dropped += p->rx_dropped;
rx_frame_errors += p->rx_frame_errors;
tx_dropped += p->tx_dropped;
}
stats->rx_dropped = rx_dropped;
stats->rx_frame_errors = rx_frame_errors;
stats->tx_dropped = tx_dropped;
}
static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
struct netlink_ext_ack *extack)
{
struct tun_struct *tun = netdev_priv(dev);
struct bpf_prog *old_prog;
old_prog = rtnl_dereference(tun->xdp_prog);
rcu_assign_pointer(tun->xdp_prog, prog);
if (old_prog)
bpf_prog_put(old_prog);
return 0;
}
static u32 tun_xdp_query(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
const struct bpf_prog *xdp_prog;
xdp_prog = rtnl_dereference(tun->xdp_prog);
if (xdp_prog)
return xdp_prog->aux->id;
return 0;
}
static int tun_xdp(struct net_device *dev, struct netdev_bpf *xdp)
{
switch (xdp->command) {
case XDP_SETUP_PROG:
return tun_xdp_set(dev, xdp->prog, xdp->extack);
case XDP_QUERY_PROG:
xdp->prog_id = tun_xdp_query(dev);
xdp->prog_attached = !!xdp->prog_id;
return 0;
default:
return -EINVAL;
}
}
static const struct net_device_ops tun_netdev_ops = {
.ndo_uninit = tun_net_uninit,
.ndo_open = tun_net_open,
.ndo_stop = tun_net_close,
.ndo_start_xmit = tun_net_xmit,
.ndo_fix_features = tun_net_fix_features,
.ndo_select_queue = tun_select_queue,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = tun_poll_controller,
#endif
.ndo_set_rx_headroom = tun_set_headroom,
.ndo_get_stats64 = tun_net_get_stats64,
};
static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
{
struct tun_struct *tun = netdev_priv(dev);
struct xdp_buff *buff = xdp->data_hard_start;
int headroom = xdp->data - xdp->data_hard_start;
struct tun_file *tfile;
u32 numqueues;
int ret = 0;
/* Assure headroom is available and buff is properly aligned */
if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))
return -ENOSPC;
*buff = *xdp;
rcu_read_lock();
numqueues = READ_ONCE(tun->numqueues);
if (!numqueues) {
ret = -ENOSPC;
goto out;
}
tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
numqueues]);
/* Encode the XDP flag into lowest bit for consumer to differ
* XDP buffer from sk_buff.
*/
if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {
this_cpu_inc(tun->pcpu_stats->tx_dropped);
ret = -ENOSPC;
}
out:
rcu_read_unlock();
return ret;
}
static void tun_xdp_flush(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
struct tun_file *tfile;
u32 numqueues;
rcu_read_lock();
numqueues = READ_ONCE(tun->numqueues);
if (!numqueues)
goto out;
tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
numqueues]);
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
tfile->socket.sk->sk_data_ready(tfile->socket.sk);
out:
rcu_read_unlock();
}
static const struct net_device_ops tap_netdev_ops = {
.ndo_uninit = tun_net_uninit,
.ndo_open = tun_net_open,
.ndo_stop = tun_net_close,
.ndo_start_xmit = tun_net_xmit,
.ndo_fix_features = tun_net_fix_features,
.ndo_set_rx_mode = tun_net_mclist,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
.ndo_select_queue = tun_select_queue,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = tun_poll_controller,
#endif
.ndo_features_check = passthru_features_check,
.ndo_set_rx_headroom = tun_set_headroom,
.ndo_get_stats64 = tun_net_get_stats64,
.ndo_bpf = tun_xdp,
.ndo_xdp_xmit = tun_xdp_xmit,
.ndo_xdp_flush = tun_xdp_flush,
};
static void tun_flow_init(struct tun_struct *tun)
{
int i;
for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++)
INIT_HLIST_HEAD(&tun->flows[i]);
tun->ageing_time = TUN_FLOW_EXPIRE;
timer_setup(&tun->flow_gc_timer, tun_flow_cleanup, 0);
mod_timer(&tun->flow_gc_timer,
round_jiffies_up(jiffies + tun->ageing_time));
}
static void tun_flow_uninit(struct tun_struct *tun)
{
del_timer_sync(&tun->flow_gc_timer);
tun_flow_flush(tun);
}
#define MIN_MTU 68
#define MAX_MTU 65535
/* Initialize net device. */
static void tun_net_init(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
switch (tun->flags & TUN_TYPE_MASK) {
case IFF_TUN:
dev->netdev_ops = &tun_netdev_ops;
/* Point-to-Point TUN Device */
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->mtu = 1500;
/* Zero header length */
dev->type = ARPHRD_NONE;
dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
break;
case IFF_TAP:
dev->netdev_ops = &tap_netdev_ops;
/* Ethernet TAP Device */
ether_setup(dev);
dev->priv_flags &= ~IFF_TX_SKB_SHARING;
dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
eth_hw_addr_random(dev);
break;
}
dev->min_mtu = MIN_MTU;
dev->max_mtu = MAX_MTU - dev->hard_header_len;
}
/* Character device part */
/* Poll */
static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = tun_get(tfile);
struct sock *sk;
__poll_t mask = 0;
if (!tun)
return EPOLLERR;
sk = tfile->socket.sk;
tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
poll_wait(file, sk_sleep(sk), wait);
if (!ptr_ring_empty(&tfile->tx_ring))
mask |= EPOLLIN | EPOLLRDNORM;
if (tun->dev->flags & IFF_UP &&
(sock_writeable(sk) ||
(!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
sock_writeable(sk))))
mask |= EPOLLOUT | EPOLLWRNORM;
if (tun->dev->reg_state != NETREG_REGISTERED)
mask = EPOLLERR;
tun_put(tun);
return mask;
}
static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
size_t len,
const struct iov_iter *it)
{
struct sk_buff *skb;
size_t linear;
int err;
int i;
if (it->nr_segs > MAX_SKB_FRAGS + 1)
return ERR_PTR(-ENOMEM);
local_bh_disable();
skb = napi_get_frags(&tfile->napi);
local_bh_enable();
if (!skb)
return ERR_PTR(-ENOMEM);
linear = iov_iter_single_seg_count(it);
err = __skb_grow(skb, linear);
if (err)
goto free;
skb->len = len;
skb->data_len = len - linear;
skb->truesize += skb->data_len;
for (i = 1; i < it->nr_segs; i++) {
size_t fragsz = it->iov[i].iov_len;
unsigned long offset;
struct page *page;
void *data;
if (fragsz == 0 || fragsz > PAGE_SIZE) {
err = -EINVAL;
goto free;
}
local_bh_disable();
data = napi_alloc_frag(fragsz);
local_bh_enable();
if (!data) {
err = -ENOMEM;
goto free;
}
page = virt_to_head_page(data);
offset = data - page_address(page);
skb_fill_page_desc(skb, i - 1, page, offset, fragsz);
}
return skb;
free:
/* frees skb and all frags allocated with napi_alloc_frag() */
napi_free_frags(&tfile->napi);
return ERR_PTR(err);
}
/* prepad is the amount to reserve at front. len is length after that.
* linear is a hint as to how much to copy (usually headers). */
static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
size_t prepad, size_t len,
size_t linear, int noblock)
{
struct sock *sk = tfile->socket.sk;
struct sk_buff *skb;
int err;
/* 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 ERR_PTR(err);
skb_reserve(skb, prepad);
skb_put(skb, linear);
skb->data_len = len - linear;
skb->len += len - linear;
return skb;
}
static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile,
struct sk_buff *skb, int more)
{
struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
struct sk_buff_head process_queue;
u32 rx_batched = tun->rx_batched;
bool rcv = false;
if (!rx_batched || (!more && skb_queue_empty(queue))) {
local_bh_disable();
netif_receive_skb(skb);
local_bh_enable();
return;
}
spin_lock(&queue->lock);
if (!more || skb_queue_len(queue) == rx_batched) {
__skb_queue_head_init(&process_queue);
skb_queue_splice_tail_init(queue, &process_queue);
rcv = true;
} else {
__skb_queue_tail(queue, skb);
}
spin_unlock(&queue->lock);
if (rcv) {
struct sk_buff *nskb;
local_bh_disable();
while ((nskb = __skb_dequeue(&process_queue)))
netif_receive_skb(nskb);
netif_receive_skb(skb);
local_bh_enable();
}
}
static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
int len, int noblock, bool zerocopy)
{
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
return false;
if (tfile->socket.sk->sk_sndbuf != INT_MAX)
return false;
if (!noblock)
return false;
if (zerocopy)
return false;
if (SKB_DATA_ALIGN(len + TUN_RX_PAD) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
return false;
return true;
}
static struct sk_buff *tun_build_skb(struct tun_struct *tun,
struct tun_file *tfile,
struct iov_iter *from,
struct virtio_net_hdr *hdr,
int len, int *skb_xdp)
{
struct page_frag *alloc_frag = &current->task_frag;
struct sk_buff *skb;
struct bpf_prog *xdp_prog;
int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
unsigned int delta = 0;
char *buf;
size_t copied;
bool xdp_xmit = false;
int err, pad = TUN_RX_PAD;
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog)
pad += TUN_HEADROOM;
buflen += SKB_DATA_ALIGN(len + pad);
rcu_read_unlock();
alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL)))
return ERR_PTR(-ENOMEM);
buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
copied = copy_page_from_iter(alloc_frag->page,
alloc_frag->offset + pad,
len, from);
if (copied != len)
return ERR_PTR(-EFAULT);
/* There's a small window that XDP may be set after the check
* of xdp_prog above, this should be rare and for simplicity
* we do XDP on skb in case the headroom is not enough.
*/
if (hdr->gso_type || !xdp_prog)
*skb_xdp = 1;
else
*skb_xdp = 0;
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog && !*skb_xdp) {
struct xdp_buff xdp;
void *orig_data;
u32 act;
xdp.data_hard_start = buf;
xdp.data = buf + pad;
xdp_set_data_meta_invalid(&xdp);
xdp.data_end = xdp.data + len;
xdp.rxq = &tfile->xdp_rxq;
orig_data = xdp.data;
act = bpf_prog_run_xdp(xdp_prog, &xdp);
switch (act) {
case XDP_REDIRECT:
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
++tfile->xdp_pending_pkts;
err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
if (err)
goto err_redirect;
rcu_read_unlock();
return NULL;
case XDP_TX:
xdp_xmit = true;
/* fall through */
case XDP_PASS:
delta = orig_data - xdp.data;
break;
default:
bpf_warn_invalid_xdp_action(act);
/* fall through */
case XDP_ABORTED:
trace_xdp_exception(tun->dev, xdp_prog, act);
/* fall through */
case XDP_DROP:
goto err_xdp;
}
}
skb = build_skb(buf, buflen);
if (!skb) {
rcu_read_unlock();
return ERR_PTR(-ENOMEM);
}
skb_reserve(skb, pad - delta);
skb_put(skb, len + delta);
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
if (xdp_xmit) {
skb->dev = tun->dev;
generic_xdp_tx(skb, xdp_prog);
rcu_read_unlock();
return NULL;
}
rcu_read_unlock();
return skb;
err_redirect:
put_page(alloc_frag->page);
err_xdp:
rcu_read_unlock();
this_cpu_inc(tun->pcpu_stats->rx_dropped);
return NULL;
}
/* Get packet from user space buffer */
static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
void *msg_control, struct iov_iter *from,
int noblock, bool more)
{
struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
struct sk_buff *skb;
size_t total_len = iov_iter_count(from);
size_t len = total_len, align = tun->align, linear;
struct virtio_net_hdr gso = { 0 };
struct tun_pcpu_stats *stats;
int good_linear;
int copylen;
bool zerocopy = false;
int err;
u32 rxhash = 0;
int skb_xdp = 1;
bool frags = tun_napi_frags_enabled(tun);
if (!(tun->dev->flags & IFF_UP))
return -EIO;
if (!(tun->flags & IFF_NO_PI)) {
if (len < sizeof(pi))
return -EINVAL;
len -= sizeof(pi);
if (!copy_from_iter_full(&pi, sizeof(pi), from))
return -EFAULT;
}
if (tun->flags & IFF_VNET_HDR) {
int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
if (len < vnet_hdr_sz)
return -EINVAL;
len -= vnet_hdr_sz;
if (!copy_from_iter_full(&gso, sizeof(gso), from))
return -EFAULT;
if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
if (tun16_to_cpu(tun, gso.hdr_len) > len)
return -EINVAL;
iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
}
if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
align += NET_IP_ALIGN;
if (unlikely(len < ETH_HLEN ||
(gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN)))
return -EINVAL;
}
good_linear = SKB_MAX_HEAD(align);
if (msg_control) {
struct iov_iter i = *from;
/* There are 256 bytes to be copied in skb, so there is
* enough room for skb expand head in case it is used.
* The rest of the buffer is mapped from userspace.
*/
copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN;
if (copylen > good_linear)
copylen = good_linear;
linear = copylen;
iov_iter_advance(&i, copylen);
if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
zerocopy = true;
}
if (!frags && tun_can_build_skb(tun, tfile, len, noblock, zerocopy)) {
/* For the packet that is not easy to be processed
* (e.g gso or jumbo packet), we will do it at after
* skb was created with generic XDP routine.
*/
skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
if (IS_ERR(skb)) {
this_cpu_inc(tun->pcpu_stats->rx_dropped);
return PTR_ERR(skb);
}
if (!skb)
return total_len;
} else {
if (!zerocopy) {
copylen = len;
if (tun16_to_cpu(tun, gso.hdr_len) > good_linear)
linear = good_linear;
else
linear = tun16_to_cpu(tun, gso.hdr_len);
}
if (frags) {
mutex_lock(&tfile->napi_mutex);
skb = tun_napi_alloc_frags(tfile, copylen, from);
/* tun_napi_alloc_frags() enforces a layout for the skb.
* If zerocopy is enabled, then this layout will be
* overwritten by zerocopy_sg_from_iter().
*/
zerocopy = false;
} else {
skb = tun_alloc_skb(tfile, align, copylen, linear,
noblock);
}
if (IS_ERR(skb)) {
if (PTR_ERR(skb) != -EAGAIN)
this_cpu_inc(tun->pcpu_stats->rx_dropped);
if (frags)
mutex_unlock(&tfile->napi_mutex);
return PTR_ERR(skb);
}
if (zerocopy)
err = zerocopy_sg_from_iter(skb, from);
else
err = skb_copy_datagram_from_iter(skb, 0, from, len);
if (err) {
this_cpu_inc(tun->pcpu_stats->rx_dropped);
kfree_skb(skb);
if (frags) {
tfile->napi.skb = NULL;
mutex_unlock(&tfile->napi_mutex);
}
return -EFAULT;
}
}
if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
kfree_skb(skb);
if (frags) {
tfile->napi.skb = NULL;
mutex_unlock(&tfile->napi_mutex);
}
return -EINVAL;
}
switch (tun->flags & TUN_TYPE_MASK) {
case IFF_TUN:
if (tun->flags & IFF_NO_PI) {
u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
switch (ip_version) {
case 4:
pi.proto = htons(ETH_P_IP);
break;
case 6:
pi.proto = htons(ETH_P_IPV6);
break;
default:
this_cpu_inc(tun->pcpu_stats->rx_dropped);
kfree_skb(skb);
return -EINVAL;
}
}
skb_reset_mac_header(skb);
skb->protocol = pi.proto;
skb->dev = tun->dev;
break;
case IFF_TAP:
if (!frags)
skb->protocol = eth_type_trans(skb, tun->dev);
break;
}
/* copy skb_ubuf_info for callback when skb has no error */
if (zerocopy) {
skb_shinfo(skb)->destructor_arg = msg_control;
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
} else if (msg_control) {
struct ubuf_info *uarg = msg_control;
uarg->callback(uarg, false);
}
skb_reset_network_header(skb);
skb_probe_transport_header(skb, 0);
if (skb_xdp) {
struct bpf_prog *xdp_prog;
int ret;
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog) {
ret = do_xdp_generic(xdp_prog, skb);
if (ret != XDP_PASS) {
rcu_read_unlock();
return total_len;
}
}
rcu_read_unlock();
}
rcu_read_lock();
if (!rcu_dereference(tun->steering_prog))
rxhash = __skb_get_hash_symmetric(skb);
rcu_read_unlock();
if (frags) {
/* Exercise flow dissector code path. */
u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb));
if (unlikely(headlen > skb_headlen(skb))) {
this_cpu_inc(tun->pcpu_stats->rx_dropped);
napi_free_frags(&tfile->napi);
mutex_unlock(&tfile->napi_mutex);
WARN_ON(1);
return -ENOMEM;
}
local_bh_disable();
napi_gro_frags(&tfile->napi);
local_bh_enable();
mutex_unlock(&tfile->napi_mutex);
} else if (tfile->napi_enabled) {
struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
int queue_len;
spin_lock_bh(&queue->lock);
__skb_queue_tail(queue, skb);
queue_len = skb_queue_len(queue);
spin_unlock(&queue->lock);
if (!more || queue_len > NAPI_POLL_WEIGHT)
napi_schedule(&tfile->napi);
local_bh_enable();
} else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
tun_rx_batched(tun, tfile, skb, more);
} else {
netif_rx_ni(skb);
}
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
stats->rx_packets++;
stats->rx_bytes += len;
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(stats);
if (rxhash)
tun_flow_update(tun, rxhash, tfile);
return total_len;
}
static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = tun_get(tfile);
ssize_t result;
if (!tun)
return -EBADFD;
result = tun_get_user(tun, tfile, NULL, from,
file->f_flags & O_NONBLOCK, false);
if (tfile->xdp_pending_pkts) {
tfile->xdp_pending_pkts = 0;
xdp_do_flush_map();
}
tun_put(tun);
return result;
}
static ssize_t tun_put_user_xdp(struct tun_struct *tun,
struct tun_file *tfile,
struct xdp_buff *xdp,
struct iov_iter *iter)
{
int vnet_hdr_sz = 0;
size_t size = xdp->data_end - xdp->data;
struct tun_pcpu_stats *stats;
size_t ret;
if (tun->flags & IFF_VNET_HDR) {
struct virtio_net_hdr gso = { 0 };
vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
if (unlikely(iov_iter_count(iter) < vnet_hdr_sz))
return -EINVAL;
if (unlikely(copy_to_iter(&gso, sizeof(gso), iter) !=
sizeof(gso)))
return -EFAULT;
iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
}
ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
stats->tx_packets++;
stats->tx_bytes += ret;
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(tun->pcpu_stats);
return ret;
}
/* Put packet to the user space buffer */
static ssize_t tun_put_user(struct tun_struct *tun,
struct tun_file *tfile,
struct sk_buff *skb,
struct iov_iter *iter)
{
struct tun_pi pi = { 0, skb->protocol };
struct tun_pcpu_stats *stats;
ssize_t total;
int vlan_offset = 0;
int vlan_hlen = 0;
int vnet_hdr_sz = 0;
if (skb_vlan_tag_present(skb))
vlan_hlen = VLAN_HLEN;
if (tun->flags & IFF_VNET_HDR)
vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
total = skb->len + vlan_hlen + vnet_hdr_sz;
if (!(tun->flags & IFF_NO_PI)) {
if (iov_iter_count(iter) < sizeof(pi))
return -EINVAL;
total += sizeof(pi);
if (iov_iter_count(iter) < total) {
/* Packet will be striped */
pi.flags |= TUN_PKT_STRIP;
}
if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
return -EFAULT;
}
if (vnet_hdr_sz) {
struct virtio_net_hdr gso;
if (iov_iter_count(iter) < vnet_hdr_sz)
return -EINVAL;
if (virtio_net_hdr_from_skb(skb, &gso,
tun_is_little_endian(tun), true)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);
pr_err("unexpected GSO type: "
"0x%x, gso_size %d, hdr_len %d\n",
sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
tun16_to_cpu(tun, gso.hdr_len));
print_hex_dump(KERN_ERR, "tun: ",
DUMP_PREFIX_NONE,
16, 1, skb->head,
min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
WARN_ON_ONCE(1);
return -EINVAL;
}
if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
return -EFAULT;
iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));
}
if (vlan_hlen) {
int ret;
struct veth veth;
veth.h_vlan_proto = skb->vlan_proto;
veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
if (ret || !iov_iter_count(iter))
goto done;
ret = copy_to_iter(&veth, sizeof(veth), iter);
if (ret != sizeof(veth) || !iov_iter_count(iter))
goto done;
}
skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
done:
/* caller is in process context, */
stats = get_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
stats->tx_packets++;
stats->tx_bytes += skb->len + vlan_hlen;
u64_stats_update_end(&stats->syncp);
put_cpu_ptr(tun->pcpu_stats);
return total;
}
static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
{
DECLARE_WAITQUEUE(wait, current);
void *ptr = NULL;
int error = 0;
ptr = ptr_ring_consume(&tfile->tx_ring);
if (ptr)
goto out;
if (noblock) {
error = -EAGAIN;
goto out;
}
add_wait_queue(&tfile->wq.wait, &wait);
current->state = TASK_INTERRUPTIBLE;
while (1) {
ptr = ptr_ring_consume(&tfile->tx_ring);
if (ptr)
break;
if (signal_pending(current)) {
error = -ERESTARTSYS;
break;
}
if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
error = -EFAULT;
break;
}
schedule();
}
current->state = TASK_RUNNING;
remove_wait_queue(&tfile->wq.wait, &wait);
out:
*err = error;
return ptr;
}
static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
struct iov_iter *to,
int noblock, void *ptr)
{
ssize_t ret;
int err;
tun_debug(KERN_INFO, tun, "tun_do_read\n");
if (!iov_iter_count(to)) {
tun_ptr_free(ptr);
return 0;
}
if (!ptr) {
/* Read frames from ring */
ptr = tun_ring_recv(tfile, noblock, &err);
if (!ptr)
return err;
}
if (tun_is_xdp_buff(ptr)) {
struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
ret = tun_put_user_xdp(tun, tfile, xdp, to);
put_page(virt_to_head_page(xdp->data));
} else {
struct sk_buff *skb = ptr;
ret = tun_put_user(tun, tfile, skb, to);
if (unlikely(ret < 0))
kfree_skb(skb);
else
consume_skb(skb);
}
return ret;
}
static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = tun_get(tfile);
ssize_t len = iov_iter_count(to), ret;
if (!tun)
return -EBADFD;
ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);
ret = min_t(ssize_t, ret, len);
if (ret > 0)
iocb->ki_pos = ret;
tun_put(tun);
return ret;
}
static void tun_prog_free(struct rcu_head *rcu)
{
struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
bpf_prog_destroy(prog->prog);
kfree(prog);
}
static int __tun_set_ebpf(struct tun_struct *tun,
struct tun_prog __rcu **prog_p,
struct bpf_prog *prog)
{
struct tun_prog *old, *new = NULL;
if (prog) {
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (!new)
return -ENOMEM;
new->prog = prog;
}
spin_lock_bh(&tun->lock);
old = rcu_dereference_protected(*prog_p,
lockdep_is_held(&tun->lock));
rcu_assign_pointer(*prog_p, new);
spin_unlock_bh(&tun->lock);
if (old)
call_rcu(&old->rcu, tun_prog_free);
return 0;
}
static void tun_free_netdev(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
BUG_ON(!(list_empty(&tun->disabled)));
free_percpu(tun->pcpu_stats);
tun_flow_uninit(tun);
security_tun_dev_free_security(tun->security);
__tun_set_ebpf(tun, &tun->steering_prog, NULL);
__tun_set_ebpf(tun, &tun->filter_prog, NULL);
}
static void tun_setup(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
tun->owner = INVALID_UID;
tun->group = INVALID_GID;
dev->ethtool_ops = &tun_ethtool_ops;
dev->needs_free_netdev = true;
dev->priv_destructor = tun_free_netdev;
/* We prefer our own queue length */
dev->tx_queue_len = TUN_READQ_SIZE;
}
/* Trivial set of netlink ops to allow deleting tun or tap
* device with netlink.
*/
static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
struct netlink_ext_ack *extack)
{
return -EINVAL;
}
static struct rtnl_link_ops tun_link_ops __read_mostly = {
.kind = DRV_NAME,
.priv_size = sizeof(struct tun_struct),
.setup = tun_setup,
.validate = tun_validate,
};
static void tun_sock_write_space(struct sock *sk)
{
struct tun_file *tfile;
wait_queue_head_t *wqueue;
if (!sock_writeable(sk))
return;
if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
wqueue = sk_sleep(sk);
if (wqueue && waitqueue_active(wqueue))
wake_up_interruptible_sync_poll(wqueue, EPOLLOUT |
EPOLLWRNORM | EPOLLWRBAND);
tfile = container_of(sk, struct tun_file, sk);
kill_fasync(&tfile->fasync, SIGIO, POLL_OUT);
}
static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
{
int ret;
struct tun_file *tfile = container_of(sock, struct tun_file, socket);
struct tun_struct *tun = tun_get(tfile);
if (!tun)
return -EBADFD;
ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
m->msg_flags & MSG_DONTWAIT,
m->msg_flags & MSG_MORE);
if (tfile->xdp_pending_pkts >= NAPI_POLL_WEIGHT ||
!(m->msg_flags & MSG_MORE)) {
tfile->xdp_pending_pkts = 0;
xdp_do_flush_map();
}
tun_put(tun);
return ret;
}
static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
int flags)
{
struct tun_file *tfile = container_of(sock, struct tun_file, socket);
struct tun_struct *tun = tun_get(tfile);
void *ptr = m->msg_control;
int ret;
if (!tun) {
ret = -EBADFD;
goto out_free;
}
if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
ret = -EINVAL;
goto out_put_tun;
}
if (flags & MSG_ERRQUEUE) {
ret = sock_recv_errqueue(sock->sk, m, total_len,
SOL_PACKET, TUN_TX_TIMESTAMP);
goto out;
}
ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, ptr);
if (ret > (ssize_t)total_len) {
m->msg_flags |= MSG_TRUNC;
ret = flags & MSG_TRUNC ? ret : total_len;
}
out:
tun_put(tun);
return ret;
out_put_tun:
tun_put(tun);
out_free:
tun_ptr_free(ptr);
return ret;
}
static int tun_ptr_peek_len(void *ptr)
{
if (likely(ptr)) {
if (tun_is_xdp_buff(ptr)) {
struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);
return xdp->data_end - xdp->data;
}
return __skb_array_len_with_tag(ptr);
} else {
return 0;
}
}
static int tun_peek_len(struct socket *sock)
{
struct tun_file *tfile = container_of(sock, struct tun_file, socket);
struct tun_struct *tun;
int ret = 0;
tun = tun_get(tfile);
if (!tun)
return 0;
ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, tun_ptr_peek_len);
tun_put(tun);
return ret;
}
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops tun_socket_ops = {
.peek_len = tun_peek_len,
.sendmsg = tun_sendmsg,
.recvmsg = tun_recvmsg,
};
static struct proto tun_proto = {
.name = "tun",
.owner = THIS_MODULE,
.obj_size = sizeof(struct tun_file),
};
static int tun_flags(struct tun_struct *tun)
{
return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP);
}
static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tun_struct *tun = netdev_priv(to_net_dev(dev));
return sprintf(buf, "0x%x\n", tun_flags(tun));
}
static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tun_struct *tun = netdev_priv(to_net_dev(dev));
return uid_valid(tun->owner)?
sprintf(buf, "%u\n",
from_kuid_munged(current_user_ns(), tun->owner)):
sprintf(buf, "-1\n");
}
static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tun_struct *tun = netdev_priv(to_net_dev(dev));
return gid_valid(tun->group) ?
sprintf(buf, "%u\n",
from_kgid_munged(current_user_ns(), tun->group)):
sprintf(buf, "-1\n");
}
static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
static struct attribute *tun_dev_attrs[] = {
&dev_attr_tun_flags.attr,
&dev_attr_owner.attr,
&dev_attr_group.attr,
NULL
};
static const struct attribute_group tun_attr_group = {
.attrs = tun_dev_attrs
};
static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
{
struct tun_struct *tun;
struct tun_file *tfile = file->private_data;
struct net_device *dev;
int err;
if (tfile->detached)
return -EINVAL;
if ((ifr->ifr_flags & IFF_NAPI_FRAGS)) {
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (!(ifr->ifr_flags & IFF_NAPI) ||
(ifr->ifr_flags & TUN_TYPE_MASK) != IFF_TAP)
return -EINVAL;
}
dev = __dev_get_by_name(net, ifr->ifr_name);
if (dev) {
if (ifr->ifr_flags & IFF_TUN_EXCL)
return -EBUSY;
if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
tun = netdev_priv(dev);
else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
tun = netdev_priv(dev);
else
return -EINVAL;
if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
!!(tun->flags & IFF_MULTI_QUEUE))
return -EINVAL;
if (tun_not_capable(tun))
return -EPERM;
err = security_tun_dev_open(tun->security);
if (err < 0)
return err;
err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER,
ifr->ifr_flags & IFF_NAPI);
if (err < 0)
return err;
if (tun->flags & IFF_MULTI_QUEUE &&
(tun->numqueues + tun->numdisabled > 1)) {
/* One or more queue has already been attached, no need
* to initialize the device again.
*/
return 0;
}
}
else {
char *name;
unsigned long flags = 0;
int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
MAX_TAP_QUEUES : 1;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
return -EPERM;
err = security_tun_dev_create();
if (err < 0)
return err;
/* Set dev type */
if (ifr->ifr_flags & IFF_TUN) {
/* TUN device */
flags |= IFF_TUN;
name = "tun%d";
} else if (ifr->ifr_flags & IFF_TAP) {
/* TAP device */
flags |= IFF_TAP;
name = "tap%d";
} else
return -EINVAL;
if (*ifr->ifr_name)
name = ifr->ifr_name;
dev = alloc_netdev_mqs(sizeof(struct tun_struct), name,
NET_NAME_UNKNOWN, tun_setup, queues,
queues);
if (!dev)
return -ENOMEM;
err = dev_get_valid_name(net, dev, name);
if (err < 0)
goto err_free_dev;
dev_net_set(dev, net);
dev->rtnl_link_ops = &tun_link_ops;
dev->ifindex = tfile->ifindex;
dev->sysfs_groups[0] = &tun_attr_group;
tun = netdev_priv(dev);
tun->dev = dev;
tun->flags = flags;
tun->txflt.count = 0;
tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
tun->align = NET_SKB_PAD;
tun->filter_attached = false;
tun->sndbuf = tfile->socket.sk->sk_sndbuf;
tun->rx_batched = 0;
RCU_INIT_POINTER(tun->steering_prog, NULL);
tun->pcpu_stats = netdev_alloc_pcpu_stats(struct tun_pcpu_stats);
if (!tun->pcpu_stats) {
err = -ENOMEM;
goto err_free_dev;
}
spin_lock_init(&tun->lock);
err = security_tun_dev_alloc_security(&tun->security);
if (err < 0)
goto err_free_stat;
tun_net_init(dev);
tun_flow_init(tun);
dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_STAG_TX;
dev->features = dev->hw_features | NETIF_F_LLTX;
dev->vlan_features = dev->features &
~(NETIF_F_HW_VLAN_CTAG_TX |
NETIF_F_HW_VLAN_STAG_TX);
INIT_LIST_HEAD(&tun->disabled);
err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI);
if (err < 0)
goto err_free_flow;
err = register_netdevice(tun->dev);
if (err < 0)
goto err_detach;
}
netif_carrier_on(tun->dev);
tun_debug(KERN_INFO, tun, "tun_set_iff\n");
tun->flags = (tun->flags & ~TUN_FEATURES) |
(ifr->ifr_flags & TUN_FEATURES);
/* Make sure persistent devices do not get stuck in
* xoff state.
*/
if (netif_running(tun->dev))
netif_tx_wake_all_queues(tun->dev);
strcpy(ifr->ifr_name, tun->dev->name);
return 0;
err_detach:
tun_detach_all(dev);
/* register_netdevice() already called tun_free_netdev() */
goto err_free_dev;
err_free_flow:
tun_flow_uninit(tun);
security_tun_dev_free_security(tun->security);
err_free_stat:
free_percpu(tun->pcpu_stats);
err_free_dev:
free_netdev(dev);
return err;
}
static void tun_get_iff(struct net *net, struct tun_struct *tun,
struct ifreq *ifr)
{
tun_debug(KERN_INFO, tun, "tun_get_iff\n");
strcpy(ifr->ifr_name, tun->dev->name);
ifr->ifr_flags = tun_flags(tun);
}
/* This is like a cut-down ethtool ops, except done via tun fd so no
* privs required. */
static int set_offload(struct tun_struct *tun, unsigned long arg)
{
netdev_features_t features = 0;
if (arg & TUN_F_CSUM) {
features |= NETIF_F_HW_CSUM;
arg &= ~TUN_F_CSUM;
if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
if (arg & TUN_F_TSO_ECN) {
features |= NETIF_F_TSO_ECN;
arg &= ~TUN_F_TSO_ECN;
}
if (arg & TUN_F_TSO4)
features |= NETIF_F_TSO;
if (arg & TUN_F_TSO6)
features |= NETIF_F_TSO6;
arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
}
arg &= ~TUN_F_UFO;
}
/* This gives the user a way to test for new features in future by
* trying to set them. */
if (arg)
return -EINVAL;
tun->set_features = features;
tun->dev->wanted_features &= ~TUN_USER_FEATURES;
tun->dev->wanted_features |= features;
netdev_update_features(tun->dev);
return 0;
}
static void tun_detach_filter(struct tun_struct *tun, int n)
{
int i;
struct tun_file *tfile;
for (i = 0; i < n; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
lock_sock(tfile->socket.sk);
sk_detach_filter(tfile->socket.sk);
release_sock(tfile->socket.sk);
}
tun->filter_attached = false;
}
static int tun_attach_filter(struct tun_struct *tun)
{
int i, ret = 0;
struct tun_file *tfile;
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
lock_sock(tfile->socket.sk);
ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
release_sock(tfile->socket.sk);
if (ret) {
tun_detach_filter(tun, i);
return ret;
}
}
tun->filter_attached = true;
return ret;
}
static void tun_set_sndbuf(struct tun_struct *tun)
{
struct tun_file *tfile;
int i;
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
tfile->socket.sk->sk_sndbuf = tun->sndbuf;
}
}
static int tun_set_queue(struct file *file, struct ifreq *ifr)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
int ret = 0;
rtnl_lock();
if (ifr->ifr_flags & IFF_ATTACH_QUEUE) {
tun = tfile->detached;
if (!tun) {
ret = -EINVAL;
goto unlock;
}
ret = security_tun_dev_attach_queue(tun->security);
if (ret < 0)
goto unlock;
ret = tun_attach(tun, file, false, tun->flags & IFF_NAPI);
} else if (ifr->ifr_flags & IFF_DETACH_QUEUE) {
tun = rtnl_dereference(tfile->tun);
if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached)
ret = -EINVAL;
else
__tun_detach(tfile, false);
} else
ret = -EINVAL;
unlock:
rtnl_unlock();
return ret;
}
static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
void __user *data)
{
struct bpf_prog *prog;
int fd;
if (copy_from_user(&fd, data, sizeof(fd)))
return -EFAULT;
if (fd == -1) {
prog = NULL;
} else {
prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
if (IS_ERR(prog))
return PTR_ERR(prog);
}
return __tun_set_ebpf(tun, prog_p, prog);
}
static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
unsigned long arg, int ifreq_len)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
void __user* argp = (void __user*)arg;
struct ifreq ifr;
kuid_t owner;
kgid_t group;
int sndbuf;
int vnet_hdr_sz;
unsigned int ifindex;
int le;
int ret;
if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) {
if (copy_from_user(&ifr, argp, ifreq_len))
return -EFAULT;
} else {
memset(&ifr, 0, sizeof(ifr));
}
if (cmd == TUNGETFEATURES) {
/* Currently this just means: "what IFF flags are valid?".
* This is needed because we never checked for invalid flags on
* TUNSETIFF.
*/
return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
(unsigned int __user*)argp);
} else if (cmd == TUNSETQUEUE)
return tun_set_queue(file, &ifr);
ret = 0;
rtnl_lock();
tun = tun_get(tfile);
if (cmd == TUNSETIFF) {
ret = -EEXIST;
if (tun)
goto unlock;
ifr.ifr_name[IFNAMSIZ-1] = '\0';
ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);
if (ret)
goto unlock;
if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
goto unlock;
}
if (cmd == TUNSETIFINDEX) {
ret = -EPERM;
if (tun)
goto unlock;
ret = -EFAULT;
if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
goto unlock;
ret = 0;
tfile->ifindex = ifindex;
goto unlock;
}
ret = -EBADFD;
if (!tun)
goto unlock;
tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
ret = 0;
switch (cmd) {
case TUNGETIFF:
tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
if (tfile->detached)
ifr.ifr_flags |= IFF_DETACH_QUEUE;
if (!tfile->socket.sk->sk_filter)
ifr.ifr_flags |= IFF_NOFILTER;
if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
break;
case TUNSETNOCSUM:
/* Disable/Enable checksum */
/* [unimplemented] */
tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
arg ? "disabled" : "enabled");
break;
case TUNSETPERSIST:
/* Disable/Enable persist mode. Keep an extra reference to the
* module to prevent the module being unprobed.
*/
if (arg && !(tun->flags & IFF_PERSIST)) {
tun->flags |= IFF_PERSIST;
__module_get(THIS_MODULE);
}
if (!arg && (tun->flags & IFF_PERSIST)) {
tun->flags &= ~IFF_PERSIST;
module_put(THIS_MODULE);
}
tun_debug(KERN_INFO, tun, "persist %s\n",
arg ? "enabled" : "disabled");
break;
case TUNSETOWNER:
/* Set owner of the device */
owner = make_kuid(current_user_ns(), arg);
if (!uid_valid(owner)) {
ret = -EINVAL;
break;
}
tun->owner = owner;
tun_debug(KERN_INFO, tun, "owner set to %u\n",
from_kuid(&init_user_ns, tun->owner));
break;
case TUNSETGROUP:
/* Set group of the device */
group = make_kgid(current_user_ns(), arg);
if (!gid_valid(group)) {
ret = -EINVAL;
break;
}
tun->group = group;
tun_debug(KERN_INFO, tun, "group set to %u\n",
from_kgid(&init_user_ns, tun->group));
break;
case TUNSETLINK:
/* Only allow setting the type when the interface is down */
if (tun->dev->flags & IFF_UP) {
tun_debug(KERN_INFO, tun,
"Linktype set failed because interface is up\n");
ret = -EBUSY;
} else {
tun->dev->type = (int) arg;
tun_debug(KERN_INFO, tun, "linktype set to %d\n",
tun->dev->type);
ret = 0;
}
break;
#ifdef TUN_DEBUG
case TUNSETDEBUG:
tun->debug = arg;
break;
#endif
case TUNSETOFFLOAD:
ret = set_offload(tun, arg);
break;
case TUNSETTXFILTER:
/* Can be set only for TAPs */
ret = -EINVAL;
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
break;
ret = update_filter(&tun->txflt, (void __user *)arg);
break;
case SIOCGIFHWADDR:
/* Get hw address */
memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
ifr.ifr_hwaddr.sa_family = tun->dev->type;
if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
break;
case SIOCSIFHWADDR:
/* Set hw address */
tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
ifr.ifr_hwaddr.sa_data);
ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
break;
case TUNGETSNDBUF:
sndbuf = tfile->socket.sk->sk_sndbuf;
if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
ret = -EFAULT;
break;
case TUNSETSNDBUF:
if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
ret = -EFAULT;
break;
}
if (sndbuf <= 0) {
ret = -EINVAL;
break;
}
tun->sndbuf = sndbuf;
tun_set_sndbuf(tun);
break;
case TUNGETVNETHDRSZ:
vnet_hdr_sz = tun->vnet_hdr_sz;
if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
ret = -EFAULT;
break;
case TUNSETVNETHDRSZ:
if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
ret = -EFAULT;
break;
}
if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
ret = -EINVAL;
break;
}
tun->vnet_hdr_sz = vnet_hdr_sz;
break;
case TUNGETVNETLE:
le = !!(tun->flags & TUN_VNET_LE);
if (put_user(le, (int __user *)argp))
ret = -EFAULT;
break;
case TUNSETVNETLE:
if (get_user(le, (int __user *)argp)) {
ret = -EFAULT;
break;
}
if (le)
tun->flags |= TUN_VNET_LE;
else
tun->flags &= ~TUN_VNET_LE;
break;
case TUNGETVNETBE:
ret = tun_get_vnet_be(tun, argp);
break;
case TUNSETVNETBE:
ret = tun_set_vnet_be(tun, argp);
break;
case TUNATTACHFILTER:
/* Can be set only for TAPs */
ret = -EINVAL;
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
break;
ret = -EFAULT;
if (copy_from_user(&tun->fprog, argp, sizeof(tun->fprog)))
break;
ret = tun_attach_filter(tun);
break;
case TUNDETACHFILTER:
/* Can be set only for TAPs */
ret = -EINVAL;
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
break;
ret = 0;
tun_detach_filter(tun, tun->numqueues);
break;
case TUNGETFILTER:
ret = -EINVAL;
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
break;
ret = -EFAULT;
if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog)))
break;
ret = 0;
break;
case TUNSETSTEERINGEBPF:
ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
break;
case TUNSETFILTEREBPF:
ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
break;
default:
ret = -EINVAL;
break;
}
unlock:
rtnl_unlock();
if (tun)
tun_put(tun);
return ret;
}
static long tun_chr_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
}
#ifdef CONFIG_COMPAT
static long tun_chr_compat_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case TUNSETIFF:
case TUNGETIFF:
case TUNSETTXFILTER:
case TUNGETSNDBUF:
case TUNSETSNDBUF:
case SIOCGIFHWADDR:
case SIOCSIFHWADDR:
arg = (unsigned long)compat_ptr(arg);
break;
default:
arg = (compat_ulong_t)arg;
break;
}
/*
* compat_ifreq is shorter than ifreq, so we must not access beyond
* the end of that structure. All fields that are used in this
* driver are compatible though, we don't need to convert the
* contents.
*/
return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
}
#endif /* CONFIG_COMPAT */
static int tun_chr_fasync(int fd, struct file *file, int on)
{
struct tun_file *tfile = file->private_data;
int ret;
if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
goto out;
if (on) {
__f_setown(file, task_pid(current), PIDTYPE_PID, 0);
tfile->flags |= TUN_FASYNC;
} else
tfile->flags &= ~TUN_FASYNC;
ret = 0;
out:
return ret;
}
static int tun_chr_open(struct inode *inode, struct file * file)
{
struct net *net = current->nsproxy->net_ns;
struct tun_file *tfile;
DBG1(KERN_INFO, "tunX: tun_chr_open\n");
tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
&tun_proto, 0);
if (!tfile)
return -ENOMEM;
RCU_INIT_POINTER(tfile->tun, NULL);
tfile->flags = 0;
tfile->ifindex = 0;
init_waitqueue_head(&tfile->wq.wait);
RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq);
tfile->socket.file = file;
tfile->socket.ops = &tun_socket_ops;
sock_init_data(&tfile->socket, &tfile->sk);
tfile->sk.sk_write_space = tun_sock_write_space;
tfile->sk.sk_sndbuf = INT_MAX;
file->private_data = tfile;
INIT_LIST_HEAD(&tfile->next);
sock_set_flag(&tfile->sk, SOCK_ZEROCOPY);
memset(&tfile->tx_ring, 0, sizeof(tfile->tx_ring));
tfile->xdp_pending_pkts = 0;
return 0;
}
static int tun_chr_close(struct inode *inode, struct file *file)
{
struct tun_file *tfile = file->private_data;
tun_detach(tfile, true);
return 0;
}
#ifdef CONFIG_PROC_FS
static void tun_chr_show_fdinfo(struct seq_file *m, struct file *file)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
rtnl_lock();
tun = tun_get(tfile);
if (tun)
tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
rtnl_unlock();
if (tun)
tun_put(tun);
seq_printf(m, "iff:\t%s\n", ifr.ifr_name);
}
#endif
static const struct file_operations tun_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read_iter = tun_chr_read_iter,
.write_iter = tun_chr_write_iter,
.poll = tun_chr_poll,
.unlocked_ioctl = tun_chr_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = tun_chr_compat_ioctl,
#endif
.open = tun_chr_open,
.release = tun_chr_close,
.fasync = tun_chr_fasync,
#ifdef CONFIG_PROC_FS
.show_fdinfo = tun_chr_show_fdinfo,
#endif
};
static struct miscdevice tun_miscdev = {
.minor = TUN_MINOR,
.name = "tun",
.nodename = "net/tun",
.fops = &tun_fops,
};
/* ethtool interface */
static int tun_get_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *cmd)
{
ethtool_link_ksettings_zero_link_mode(cmd, supported);
ethtool_link_ksettings_zero_link_mode(cmd, advertising);
cmd->base.speed = SPEED_10;
cmd->base.duplex = DUPLEX_FULL;
cmd->base.port = PORT_TP;
cmd->base.phy_address = 0;
cmd->base.autoneg = AUTONEG_DISABLE;
return 0;
}
static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
struct tun_struct *tun = netdev_priv(dev);
strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
strlcpy(info->version, DRV_VERSION, sizeof(info->version));
switch (tun->flags & TUN_TYPE_MASK) {
case IFF_TUN:
strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
break;
case IFF_TAP:
strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
break;
}
}
static u32 tun_get_msglevel(struct net_device *dev)
{
#ifdef TUN_DEBUG
struct tun_struct *tun = netdev_priv(dev);
return tun->debug;
#else
return -EOPNOTSUPP;
#endif
}
static void tun_set_msglevel(struct net_device *dev, u32 value)
{
#ifdef TUN_DEBUG
struct tun_struct *tun = netdev_priv(dev);
tun->debug = value;
#endif
}
static int tun_get_coalesce(struct net_device *dev,
struct ethtool_coalesce *ec)
{
struct tun_struct *tun = netdev_priv(dev);
ec->rx_max_coalesced_frames = tun->rx_batched;
return 0;
}
static int tun_set_coalesce(struct net_device *dev,
struct ethtool_coalesce *ec)
{
struct tun_struct *tun = netdev_priv(dev);
if (ec->rx_max_coalesced_frames > NAPI_POLL_WEIGHT)
tun->rx_batched = NAPI_POLL_WEIGHT;
else
tun->rx_batched = ec->rx_max_coalesced_frames;
return 0;
}
static const struct ethtool_ops tun_ethtool_ops = {
.get_drvinfo = tun_get_drvinfo,
.get_msglevel = tun_get_msglevel,
.set_msglevel = tun_set_msglevel,
.get_link = ethtool_op_get_link,
.get_ts_info = ethtool_op_get_ts_info,
.get_coalesce = tun_get_coalesce,
.set_coalesce = tun_set_coalesce,
.get_link_ksettings = tun_get_link_ksettings,
};
static int tun_queue_resize(struct tun_struct *tun)
{
struct net_device *dev = tun->dev;
struct tun_file *tfile;
struct ptr_ring **rings;
int n = tun->numqueues + tun->numdisabled;
int ret, i;
rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
if (!rings)
return -ENOMEM;
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
rings[i] = &tfile->tx_ring;
}
list_for_each_entry(tfile, &tun->disabled, next)
rings[i++] = &tfile->tx_ring;
ret = ptr_ring_resize_multiple(rings, n,
dev->tx_queue_len, GFP_KERNEL,
tun_ptr_free);
kfree(rings);
return ret;
}
static int tun_device_event(struct notifier_block *unused,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct tun_struct *tun = netdev_priv(dev);
if (dev->rtnl_link_ops != &tun_link_ops)
return NOTIFY_DONE;
switch (event) {
case NETDEV_CHANGE_TX_QUEUE_LEN:
if (tun_queue_resize(tun))
return NOTIFY_BAD;
break;
default:
break;
}
return NOTIFY_DONE;
}
static struct notifier_block tun_notifier_block __read_mostly = {
.notifier_call = tun_device_event,
};
static int __init tun_init(void)
{
int ret = 0;
pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
ret = rtnl_link_register(&tun_link_ops);
if (ret) {
pr_err("Can't register link_ops\n");
goto err_linkops;
}
ret = misc_register(&tun_miscdev);
if (ret) {
pr_err("Can't register misc device %d\n", TUN_MINOR);
goto err_misc;
}
ret = register_netdevice_notifier(&tun_notifier_block);
if (ret) {
pr_err("Can't register netdevice notifier\n");
goto err_notifier;
}
return 0;
err_notifier:
misc_deregister(&tun_miscdev);
err_misc:
rtnl_link_unregister(&tun_link_ops);
err_linkops:
return ret;
}
static void tun_cleanup(void)
{
misc_deregister(&tun_miscdev);
rtnl_link_unregister(&tun_link_ops);
unregister_netdevice_notifier(&tun_notifier_block);
}
/* Get an underlying socket object from tun file. Returns error unless file is
* attached to a device. The returned object works like a packet socket, it
* can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
* holding a reference to the file for as long as the socket is in use. */
struct socket *tun_get_socket(struct file *file)
{
struct tun_file *tfile;
if (file->f_op != &tun_fops)
return ERR_PTR(-EINVAL);
tfile = file->private_data;
if (!tfile)
return ERR_PTR(-EBADFD);
return &tfile->socket;
}
EXPORT_SYMBOL_GPL(tun_get_socket);
struct ptr_ring *tun_get_tx_ring(struct file *file)
{
struct tun_file *tfile;
if (file->f_op != &tun_fops)
return ERR_PTR(-EINVAL);
tfile = file->private_data;
if (!tfile)
return ERR_PTR(-EBADFD);
return &tfile->tx_ring;
}
EXPORT_SYMBOL_GPL(tun_get_tx_ring);
module_init(tun_init);
module_exit(tun_cleanup);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(TUN_MINOR);
MODULE_ALIAS("devname:net/tun");
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