blob: 53f4f37b0ffd3e92bc742b0ee42948c5bdab0b1e [file] [log] [blame]
/*
* 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 <net/xdp.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>
#include <linux/proc_fs.h>
static void tun_default_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *cmd);
/* 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_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;
bool napi_frags_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;
};
struct tun_page {
struct page *page;
int count;
};
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 ____cacheline_aligned_in_smp;
};
#define TUN_NUM_FLOW_ENTRIES 1024
#define TUN_MASK_FLOW_ENTRIES (TUN_NUM_FLOW_ENTRIES - 1)
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 ethtool_link_ksettings link_ksettings;
};
struct veth {
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
};
bool tun_is_xdp_frame(void *ptr)
{
return (unsigned long)ptr & TUN_XDP_FLAG;
}
EXPORT_SYMBOL(tun_is_xdp_frame);
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, bool napi_frags)
{
tfile->napi_enabled = napi_en;
tfile->napi_frags_enabled = napi_en && napi_frags;
if (napi_en) {
netif_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
NAPI_POLL_WEIGHT);
napi_enable(&tfile->napi);
}
}
static void tun_napi_disable(struct tun_file *tfile)
{
if (tfile->napi_enabled)
napi_disable(&tfile->napi);
}
static void tun_napi_del(struct tun_file *tfile)
{
if (tfile->napi_enabled)
netif_napi_del(&tfile->napi);
}
static bool tun_napi_frags_enabled(const struct tun_file *tfile)
{
return tfile->napi_frags_enabled;
}
#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 & TUN_MASK_FLOW_ENTRIES;
}
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;
head = &tun->flows[tun_hashfn(rxhash)];
rcu_read_lock();
e = tun_flow_find(head, rxhash);
if (likely(e)) {
/* TODO: keep queueing to old queue until it's empty? */
if (e->queue_index != queue_index)
e->queue_index = queue_index;
if (e->updated != jiffies)
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);
}
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. 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.
*/
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);
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;
}
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,
struct net_device *sb_dev,
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;
}
void tun_ptr_free(void *ptr)
{
if (!ptr)
return;
if (tun_is_xdp_frame(ptr)) {
struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
xdp_return_frame(xdpf);
} else {
__skb_array_destroy_skb(ptr);
}
}
EXPORT_SYMBOL_GPL(tun_ptr_free);
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_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(tfile);
tun_napi_del(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);
}
if (tun)
xdp_rxq_info_unreg(&tfile->xdp_rxq);
ptr_ring_cleanup(&tfile->tx_ring, tun_ptr_free);
sock_put(&tfile->sk);
}
}
static void tun_detach(struct tun_file *tfile, bool clean)
{
struct tun_struct *tun;
struct net_device *dev;
rtnl_lock();
tun = rtnl_dereference(tfile->tun);
dev = tun ? tun->dev : NULL;
__tun_detach(tfile, clean);
if (dev)
netdev_state_change(dev);
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(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(tfile);
/* Drop read queue */
tun_queue_purge(tfile);
xdp_rxq_info_unreg(&tfile->xdp_rxq);
sock_put(&tfile->sk);
}
list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
tun_enable_queue(tfile);
tun_queue_purge(tfile);
xdp_rxq_info_unreg(&tfile->xdp_rxq);
sock_put(&tfile->sk);
}
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, bool napi_frags)
{
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_resize(&tfile->tx_ring, dev->tx_queue_len,
GFP_KERNEL, tun_ptr_free)) {
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 = xdp_rxq_info_reg_mem_model(&tfile->xdp_rxq,
MEM_TYPE_PAGE_SHARED, NULL);
if (err < 0) {
xdp_rxq_info_unreg(&tfile->xdp_rxq);
goto out;
}
err = 0;
}
if (tfile->detached) {
tun_enable_queue(tfile);
} else {
sock_hold(&tfile->sk);
tun_napi_init(tun, tfile, napi, napi_frags);
}
if (rtnl_dereference(tun->xdp_prog))
sock_set_flag(&tfile->sk, SOCK_XDP);
/* device is allowed to go away first, so no need to hold extra
* refcnt.
*/
/* Publish tfile->tun and tun->tfiles only after we've fully
* initialized tfile; otherwise we risk using half-initialized
* object.
*/
rcu_assign_pointer(tfile->tun, tun);
rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
tun->numqueues++;
tun_set_real_num_queues(tun);
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.
*/
struct tun_flow_entry *e;
__u32 rxhash;
rxhash = __skb_get_hash_symmetric(skb);
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);
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);
}
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 tun_file *tfile;
struct bpf_prog *old_prog;
int i;
old_prog = rtnl_dereference(tun->xdp_prog);
rcu_assign_pointer(tun->xdp_prog, prog);
if (old_prog)
bpf_prog_put(old_prog);
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
if (prog)
sock_set_flag(&tfile->sk, SOCK_XDP);
else
sock_reset_flag(&tfile->sk, SOCK_XDP);
}
list_for_each_entry(tfile, &tun->disabled, next) {
if (prog)
sock_set_flag(&tfile->sk, SOCK_XDP);
else
sock_reset_flag(&tfile->sk, SOCK_XDP);
}
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);
return 0;
default:
return -EINVAL;
}
}
static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
{
if (new_carrier) {
struct tun_struct *tun = netdev_priv(dev);
if (!tun->numqueues)
return -EPERM;
netif_carrier_on(dev);
} else {
netif_carrier_off(dev);
}
return 0;
}
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,
.ndo_set_rx_headroom = tun_set_headroom,
.ndo_get_stats64 = tun_net_get_stats64,
.ndo_change_carrier = tun_net_change_carrier,
};
static void __tun_xdp_flush_tfile(struct tun_file *tfile)
{
/* 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);
}
static int tun_xdp_xmit(struct net_device *dev, int n,
struct xdp_frame **frames, u32 flags)
{
struct tun_struct *tun = netdev_priv(dev);
struct tun_file *tfile;
u32 numqueues;
int drops = 0;
int cnt = n;
int i;
if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
return -EINVAL;
rcu_read_lock();
numqueues = READ_ONCE(tun->numqueues);
if (!numqueues) {
rcu_read_unlock();
return -ENXIO; /* Caller will free/return all frames */
}
tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
numqueues]);
spin_lock(&tfile->tx_ring.producer_lock);
for (i = 0; i < n; i++) {
struct xdp_frame *xdp = frames[i];
/* Encode the XDP flag into lowest bit for consumer to differ
* XDP buffer from sk_buff.
*/
void *frame = tun_xdp_to_ptr(xdp);
if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
this_cpu_inc(tun->pcpu_stats->tx_dropped);
xdp_return_frame_rx_napi(xdp);
drops++;
}
}
spin_unlock(&tfile->tx_ring.producer_lock);
if (flags & XDP_XMIT_FLUSH)
__tun_xdp_flush_tfile(tfile);
rcu_read_unlock();
return cnt - drops;
}
static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
{
struct xdp_frame *frame = convert_to_xdp_frame(xdp);
if (unlikely(!frame))
return -EOVERFLOW;
return tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH);
}
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,
.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_change_carrier = tun_net_change_carrier,
};
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;
}
static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
{
struct sock *sk = tfile->socket.sk;
return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
}
/* 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;
/* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
* guarantee EPOLLOUT to be raised by either here or
* tun_sock_write_space(). Then process could get notification
* after it writes to a down device and meets -EIO.
*/
if (tun_sock_writeable(tun, tfile) ||
(!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
tun_sock_writeable(tun, tfile)))
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;
struct page *page;
void *frag;
if (fragsz == 0 || fragsz > PAGE_SIZE) {
err = -EINVAL;
goto free;
}
frag = netdev_alloc_frag(fragsz);
if (!frag) {
err = -ENOMEM;
goto free;
}
page = virt_to_head_page(frag);
skb_fill_page_desc(skb, i - 1, page,
frag - page_address(page), 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();
skb_record_rx_queue(skb, tfile->queue_index);
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))) {
skb_record_rx_queue(nskb, tfile->queue_index);
netif_receive_skb(nskb);
}
skb_record_rx_queue(skb, tfile->queue_index);
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 page_frag *alloc_frag, char *buf,
int buflen, int len, int pad)
{
struct sk_buff *skb = build_skb(buf, buflen);
if (!skb)
return ERR_PTR(-ENOMEM);
skb_reserve(skb, pad);
skb_put(skb, len);
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
return skb;
}
static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
struct xdp_buff *xdp, u32 act)
{
int err;
switch (act) {
case XDP_REDIRECT:
err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
if (err)
return err;
break;
case XDP_TX:
err = tun_xdp_tx(tun->dev, xdp);
if (err < 0)
return err;
break;
case XDP_PASS:
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:
this_cpu_inc(tun->pcpu_stats->rx_dropped);
break;
}
return act;
}
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 bpf_prog *xdp_prog;
int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
char *buf;
size_t copied;
int pad = TUN_RX_PAD;
int err = 0;
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog)
pad += XDP_PACKET_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;
return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
}
*skb_xdp = 0;
local_bh_disable();
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog) {
struct xdp_buff xdp;
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;
act = bpf_prog_run_xdp(xdp_prog, &xdp);
if (act == XDP_REDIRECT || act == XDP_TX) {
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
}
err = tun_xdp_act(tun, xdp_prog, &xdp, act);
if (err < 0)
goto err_xdp;
if (err == XDP_REDIRECT)
xdp_do_flush_map();
if (err != XDP_PASS)
goto out;
pad = xdp.data - xdp.data_hard_start;
len = xdp.data_end - xdp.data;
}
rcu_read_unlock();
local_bh_enable();
return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
err_xdp:
put_page(alloc_frag->page);
out:
rcu_read_unlock();
local_bh_enable();
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(tfile);
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;
local_bh_disable();
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();
local_bh_enable();
return total_len;
}
}
rcu_read_unlock();
local_bh_enable();
}
/* Compute the costly rx hash only if needed for flow updates.
* We may get a very small possibility of OOO during switching, not
* worth to optimize.
*/
if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 &&
!tfile->detached)
rxhash = __skb_get_hash_symmetric(skb);
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);
tun_put(tun);
return result;
}
static ssize_t tun_put_user_xdp(struct tun_struct *tun,
struct tun_file *tfile,
struct xdp_frame *xdp_frame,
struct iov_iter *iter)
{
int vnet_hdr_sz = 0;
size_t size = xdp_frame->len;
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_frame->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,
vlan_hlen)) {
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);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
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();
}
__set_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_frame(ptr)) {
struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
ret = tun_put_user_xdp(tun, tfile, xdpf, to);
xdp_return_frame(xdpf);
} 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;
tun_default_link_ksettings(dev, &tun->link_ksettings);
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)
{
NL_SET_ERR_MSG(extack,
"tun/tap creation via rtnetlink is not supported.");
return -EOPNOTSUPP;
}
static size_t tun_get_size(const struct net_device *dev)
{
BUILD_BUG_ON(sizeof(u32) != sizeof(uid_t));
BUILD_BUG_ON(sizeof(u32) != sizeof(gid_t));
return nla_total_size(sizeof(uid_t)) + /* OWNER */
nla_total_size(sizeof(gid_t)) + /* GROUP */
nla_total_size(sizeof(u8)) + /* TYPE */
nla_total_size(sizeof(u8)) + /* PI */
nla_total_size(sizeof(u8)) + /* VNET_HDR */
nla_total_size(sizeof(u8)) + /* PERSIST */
nla_total_size(sizeof(u8)) + /* MULTI_QUEUE */
nla_total_size(sizeof(u32)) + /* NUM_QUEUES */
nla_total_size(sizeof(u32)) + /* NUM_DISABLED_QUEUES */
0;
}
static int tun_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
if (nla_put_u8(skb, IFLA_TUN_TYPE, tun->flags & TUN_TYPE_MASK))
goto nla_put_failure;
if (uid_valid(tun->owner) &&
nla_put_u32(skb, IFLA_TUN_OWNER,
from_kuid_munged(current_user_ns(), tun->owner)))
goto nla_put_failure;
if (gid_valid(tun->group) &&
nla_put_u32(skb, IFLA_TUN_GROUP,
from_kgid_munged(current_user_ns(), tun->group)))
goto nla_put_failure;
if (nla_put_u8(skb, IFLA_TUN_PI, !(tun->flags & IFF_NO_PI)))
goto nla_put_failure;
if (nla_put_u8(skb, IFLA_TUN_VNET_HDR, !!(tun->flags & IFF_VNET_HDR)))
goto nla_put_failure;
if (nla_put_u8(skb, IFLA_TUN_PERSIST, !!(tun->flags & IFF_PERSIST)))
goto nla_put_failure;
if (nla_put_u8(skb, IFLA_TUN_MULTI_QUEUE,
!!(tun->flags & IFF_MULTI_QUEUE)))
goto nla_put_failure;
if (tun->flags & IFF_MULTI_QUEUE) {
if (nla_put_u32(skb, IFLA_TUN_NUM_QUEUES, tun->numqueues))
goto nla_put_failure;
if (nla_put_u32(skb, IFLA_TUN_NUM_DISABLED_QUEUES,
tun->numdisabled))
goto nla_put_failure;
}
return 0;
nla_put_failure:
return -EMSGSIZE;
}
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,
.get_size = tun_get_size,
.fill_info = tun_fill_info,
};
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 void tun_put_page(struct tun_page *tpage)
{
if (tpage->page)
__page_frag_cache_drain(tpage->page, tpage->count);
}
static int tun_xdp_one(struct tun_struct *tun,
struct tun_file *tfile,
struct xdp_buff *xdp, int *flush,
struct tun_page *tpage)
{
unsigned int datasize = xdp->data_end - xdp->data;
struct tun_xdp_hdr *hdr = xdp->data_hard_start;
struct virtio_net_hdr *gso = &hdr->gso;
struct tun_pcpu_stats *stats;
struct bpf_prog *xdp_prog;
struct sk_buff *skb = NULL;
u32 rxhash = 0, act;
int buflen = hdr->buflen;
int err = 0;
bool skb_xdp = false;
struct page *page;
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog) {
if (gso->gso_type) {
skb_xdp = true;
goto build;
}
xdp_set_data_meta_invalid(xdp);
xdp->rxq = &tfile->xdp_rxq;
act = bpf_prog_run_xdp(xdp_prog, xdp);
err = tun_xdp_act(tun, xdp_prog, xdp, act);
if (err < 0) {
put_page(virt_to_head_page(xdp->data));
return err;
}
switch (err) {
case XDP_REDIRECT:
*flush = true;
/* fall through */
case XDP_TX:
return 0;
case XDP_PASS:
break;
default:
page = virt_to_head_page(xdp->data);
if (tpage->page == page) {
++tpage->count;
} else {
tun_put_page(tpage);
tpage->page = page;
tpage->count = 1;
}
return 0;
}
}
build:
skb = build_skb(xdp->data_hard_start, buflen);
if (!skb) {
err = -ENOMEM;
goto out;
}
skb_reserve(skb, xdp->data - xdp->data_hard_start);
skb_put(skb, xdp->data_end - xdp->data);
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);
err = -EINVAL;
goto out;
}
skb->protocol = eth_type_trans(skb, tun->dev);
skb_reset_network_header(skb);
skb_probe_transport_header(skb, 0);
if (skb_xdp) {
err = do_xdp_generic(xdp_prog, skb);
if (err != XDP_PASS)
goto out;
}
if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
!tfile->detached)
rxhash = __skb_get_hash_symmetric(skb);
skb_record_rx_queue(skb, tfile->queue_index);
netif_receive_skb(skb);
/* No need for get_cpu_ptr() here since this function is
* always called with bh disabled
*/
stats = this_cpu_ptr(tun->pcpu_stats);
u64_stats_update_begin(&stats->syncp);
stats->rx_packets++;
stats->rx_bytes += datasize;
u64_stats_update_end(&stats->syncp);
if (rxhash)
tun_flow_update(tun, rxhash, tfile);
out:
return err;
}
static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
{
int ret, i;
struct tun_file *tfile = container_of(sock, struct tun_file, socket);
struct tun_struct *tun = tun_get(tfile);
struct tun_msg_ctl *ctl = m->msg_control;
struct xdp_buff *xdp;
if (!tun)
return -EBADFD;
if (ctl && (ctl->type == TUN_MSG_PTR)) {
struct tun_page tpage;
int n = ctl->num;
int flush = 0;
memset(&tpage, 0, sizeof(tpage));
local_bh_disable();
rcu_read_lock();
for (i = 0; i < n; i++) {
xdp = &((struct xdp_buff *)ctl->ptr)[i];
tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
}
if (flush)
xdp_do_flush_map();
rcu_read_unlock();
local_bh_enable();
tun_put_page(&tpage);
ret = total_len;
goto out;
}
ret = tun_get_user(tun, tfile, ctl ? ctl->ptr : NULL, &m->msg_iter,
m->msg_flags & MSG_DONTWAIT,
m->msg_flags & MSG_MORE);
out:
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_frame(ptr)) {
struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
return xdpf->len;
}
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,
ifr->ifr_flags & IFF_NAPI_FRAGS);
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.
*/
netdev_state_change(dev);
return 0;
}
tun->flags = (tun->flags & ~TUN_FEATURES) |
(ifr->ifr_flags & TUN_FEATURES);
netdev_state_change(dev);
} else {
char *name;
unsigned long flags = 0