diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/net/tun.c | 3778 |
1 files changed, 3778 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c new file mode 100644 index 000000000..367255bb4 --- /dev/null +++ b/drivers/net/tun.c @@ -0,0 +1,3778 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * TUN - Universal TUN/TAP device driver. + * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> + * + * $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 <net/ip_tunnels.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/ieee802154.h> +#include <linux/if_ltalk.h> +#include <uapi/linux/if_fddi.h> +#include <uapi/linux/if_hippi.h> +#include <uapi/linux/if_fc.h> +#include <net/ax25.h> +#include <net/rose.h> +#include <net/6lowpan.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); + +#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) + +/* 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 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; + u32 msg_enable; + 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; + atomic_long_t rx_frame_errors; + struct bpf_prog __rcu *xdp_prog; + struct tun_prog __rcu *steering_prog; + struct tun_prog __rcu *filter_prog; + struct ethtool_link_ksettings link_ksettings; + /* init args */ + struct file *file; + struct ifreq *ifr; +}; + +struct veth { + __be16 h_vlan_proto; + __be16 h_vlan_TCI; +}; + +static void tun_flow_init(struct tun_struct *tun); +static void tun_flow_uninit(struct tun_struct *tun); + +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_tx(tun->dev, &tfile->napi, tun_napi_poll); + napi_enable(&tfile->napi); + } +} + +static void tun_napi_enable(struct tun_file *tfile) +{ + if (tfile->napi_enabled) + 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) { + netif_info(tun, tx_queued, tun->dev, + "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) +{ + netif_info(tun, tx_queued, tun->dev, "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; + + 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 (READ_ONCE(e->queue_index) != queue_index) + WRITE_ONCE(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; + u32 numqueues; + u16 ret = 0; + + numqueues = READ_ONCE(tun->numqueues); + if (!numqueues) + return 0; + + prog = rcu_dereference(tun->steering_prog); + if (prog) + ret = bpf_prog_run_clear_cb(prog->prog, skb); + + return ret % numqueues; +} + +static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, + struct net_device *sb_dev) +{ + 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) { + if (!tfile->detached) + 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; + rcu_assign_pointer(tun->tfiles[tun->numqueues - 1], + NULL); + + --tun->numqueues; + if (clean) { + RCU_INIT_POINTER(tfile->tun, NULL); + sock_put(&tfile->sk); + } else { + tun_disable_queue(tun, tfile); + tun_napi_disable(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); + } +} + +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(); + + if (clean) + sock_put(&tfile->sk); +} + +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_napi_del(tfile); + 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, + bool publish_tun) +{ + 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, 0); + 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); + tun_napi_enable(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. + */ + if (publish_tun) + 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; + +static int tun_net_init(struct net_device *dev) +{ + struct tun_struct *tun = netdev_priv(dev); + struct ifreq *ifr = tun->ifr; + int err; + + dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); + if (!dev->tstats) + return -ENOMEM; + + spin_lock_init(&tun->lock); + + err = security_tun_dev_alloc_security(&tun->security); + if (err < 0) { + free_percpu(dev->tstats); + return err; + } + + 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); + + tun->flags = (tun->flags & ~TUN_FEATURES) | + (ifr->ifr_flags & TUN_FEATURES); + + INIT_LIST_HEAD(&tun->disabled); + err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI, + ifr->ifr_flags & IFF_NAPI_FRAGS, false); + if (err < 0) { + tun_flow_uninit(tun); + security_tun_dev_free_security(tun->security); + free_percpu(dev->tstats); + return err; + } + return 0; +} + +/* 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) +{ + netif_tx_start_all_queues(dev); + + 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_branch_unlikely(&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); + enum skb_drop_reason drop_reason; + int txq = skb->queue_mapping; + struct netdev_queue *queue; + 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 (!tfile) { + drop_reason = SKB_DROP_REASON_DEV_READY; + goto drop; + } + + if (!rcu_dereference(tun->steering_prog)) + tun_automq_xmit(tun, skb); + + netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len); + + /* 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)) { + drop_reason = SKB_DROP_REASON_TAP_TXFILTER; + goto drop; + } + + if (tfile->socket.sk->sk_filter && + sk_filter(tfile->socket.sk, skb)) { + drop_reason = SKB_DROP_REASON_SOCKET_FILTER; + goto drop; + } + + len = run_ebpf_filter(tun, skb, len); + if (len == 0) { + drop_reason = SKB_DROP_REASON_TAP_FILTER; + goto drop; + } + + if (pskb_trim(skb, len)) { + drop_reason = SKB_DROP_REASON_NOMEM; + goto drop; + } + + if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) { + drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT; + 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_ct(skb); + + if (ptr_ring_produce(&tfile->tx_ring, skb)) { + drop_reason = SKB_DROP_REASON_FULL_RING; + goto drop; + } + + /* NETIF_F_LLTX requires to do our own update of trans_start */ + queue = netdev_get_tx_queue(dev, txq); + txq_trans_cond_update(queue); + + /* 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: + dev_core_stats_tx_dropped_inc(dev); + skb_tx_error(skb); + kfree_skb_reason(skb, drop_reason); + 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) +{ + struct tun_struct *tun = netdev_priv(dev); + + dev_get_tstats64(dev, stats); + + stats->rx_frame_errors += + (unsigned long)atomic_long_read(&tun->rx_frame_errors); +} + +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 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); + 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_init = tun_net_init, + .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 nxmit = 0; + int i; + + if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK)) + return -EINVAL; + + rcu_read_lock(); + +resample: + 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]); + if (unlikely(!tfile)) + goto resample; + + 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)) { + dev_core_stats_tx_dropped_inc(dev); + break; + } + nxmit++; + } + spin_unlock(&tfile->tx_ring.producer_lock); + + if (flags & XDP_XMIT_FLUSH) + __tun_xdp_flush_tfile(tfile); + + rcu_read_unlock(); + return nxmit; +} + +static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp) +{ + struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp); + int nxmit; + + if (unlikely(!frame)) + return -EOVERFLOW; + + nxmit = tun_xdp_xmit(dev, 1, &frame, XDP_XMIT_FLUSH); + if (!nxmit) + xdp_return_frame_rx_napi(frame); + return nxmit; +} + +static const struct net_device_ops tap_netdev_ops = { + .ndo_init = tun_net_init, + .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 = dev_get_tstats64, + .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_initialize(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; + dev->header_ops = &ip_tunnel_header_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; + + 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 || + len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN)) + return ERR_PTR(-EMSGSIZE); + + 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 + XDP_PACKET_HEADROOM) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) + return false; + + return true; +} + +static struct sk_buff *__tun_build_skb(struct tun_file *tfile, + 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); + skb_set_owner_w(skb, tfile->socket.sk); + + 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) { + dev_core_stats_rx_dropped_inc(tun->dev); + return err; + } + dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data); + break; + case XDP_TX: + err = tun_xdp_tx(tun->dev, xdp); + if (err < 0) { + dev_core_stats_rx_dropped_inc(tun->dev); + return err; + } + dev_sw_netstats_rx_add(tun->dev, xdp->data_end - xdp->data); + break; + case XDP_PASS: + break; + default: + bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act); + fallthrough; + case XDP_ABORTED: + trace_xdp_exception(tun->dev, xdp_prog, act); + fallthrough; + case XDP_DROP: + dev_core_stats_rx_dropped_inc(tun->dev); + 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 = ¤t->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(tfile, 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_init_buff(&xdp, buflen, &tfile->xdp_rxq); + xdp_prepare_buff(&xdp, buf, pad, len, false); + + 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) { + if (act == XDP_REDIRECT || act == XDP_TX) + put_page(alloc_frag->page); + goto out; + } + + if (err == XDP_REDIRECT) + xdp_do_flush(); + 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(tfile, alloc_frag, buf, buflen, len, pad); + +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 }; + int good_linear; + int copylen; + bool zerocopy = false; + int err; + u32 rxhash = 0; + int skb_xdp = 1; + bool frags = tun_napi_frags_enabled(tfile); + enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; + + 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); + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop; + 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); + } + + err = PTR_ERR_OR_ZERO(skb); + if (err) + goto drop; + + if (zerocopy) + err = zerocopy_sg_from_iter(skb, from); + else + err = skb_copy_datagram_from_iter(skb, 0, from, len); + + if (err) { + err = -EFAULT; + drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT; + goto drop; + } + } + + if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) { + atomic_long_inc(&tun->rx_frame_errors); + err = -EINVAL; + goto free_skb; + } + + 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: + err = -EINVAL; + goto drop; + } + } + + skb_reset_mac_header(skb); + skb->protocol = pi.proto; + skb->dev = tun->dev; + break; + case IFF_TAP: + if (frags && !pskb_may_pull(skb, ETH_HLEN)) { + err = -ENOMEM; + drop_reason = SKB_DROP_REASON_HDR_TRUNC; + goto drop; + } + skb->protocol = eth_type_trans(skb, tun->dev); + break; + } + + /* copy skb_ubuf_info for callback when skb has no error */ + if (zerocopy) { + skb_zcopy_init(skb, msg_control); + } else if (msg_control) { + struct ubuf_info *uarg = msg_control; + uarg->callback(NULL, uarg, false); + } + + skb_reset_network_header(skb); + skb_probe_transport_header(skb); + skb_record_rx_queue(skb, tfile->queue_index); + + 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(); + goto unlock_frags; + } + } + 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); + + rcu_read_lock(); + if (unlikely(!(tun->dev->flags & IFF_UP))) { + err = -EIO; + rcu_read_unlock(); + drop_reason = SKB_DROP_REASON_DEV_READY; + goto drop; + } + + if (frags) { + u32 headlen; + + /* Exercise flow dissector code path. */ + skb_push(skb, ETH_HLEN); + headlen = eth_get_headlen(tun->dev, skb->data, + skb_headlen(skb)); + + if (unlikely(headlen > skb_headlen(skb))) { + WARN_ON_ONCE(1); + err = -ENOMEM; + dev_core_stats_rx_dropped_inc(tun->dev); +napi_busy: + napi_free_frags(&tfile->napi); + rcu_read_unlock(); + mutex_unlock(&tfile->napi_mutex); + return err; + } + + if (likely(napi_schedule_prep(&tfile->napi))) { + local_bh_disable(); + napi_gro_frags(&tfile->napi); + napi_complete(&tfile->napi); + local_bh_enable(); + } else { + err = -EBUSY; + goto napi_busy; + } + 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); + + if (unlikely(tfile->detached)) { + spin_unlock_bh(&queue->lock); + rcu_read_unlock(); + err = -EBUSY; + goto free_skb; + } + + __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(skb); + } + rcu_read_unlock(); + + preempt_disable(); + dev_sw_netstats_rx_add(tun->dev, len); + preempt_enable(); + + if (rxhash) + tun_flow_update(tun, rxhash, tfile); + + return total_len; + +drop: + if (err != -EAGAIN) + dev_core_stats_rx_dropped_inc(tun->dev); + +free_skb: + if (!IS_ERR_OR_NULL(skb)) + kfree_skb_reason(skb, drop_reason); + +unlock_frags: + if (frags) { + tfile->napi.skb = NULL; + mutex_unlock(&tfile->napi_mutex); + } + + return err ?: 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; + int noblock = 0; + + if (!tun) + return -EBADFD; + + if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT)) + noblock = 1; + + result = tun_get_user(tun, tfile, NULL, from, noblock, 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; + 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; + + preempt_disable(); + dev_sw_netstats_tx_add(tun->dev, 1, ret); + preempt_enable(); + + 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 }; + 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, */ + preempt_disable(); + dev_sw_netstats_tx_add(tun->dev, 1, skb->len + vlan_hlen); + preempt_enable(); + + 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->socket.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->socket.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; + + 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; + int noblock = 0; + + if (!tun) + return -EBADFD; + + if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT)) + noblock = 1; + + ret = tun_do_read(tun, tfile, to, noblock, 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(dev->tstats); + 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 bpf_prog *xdp_prog; + struct sk_buff *skb = NULL; + struct sk_buff_head *queue; + u32 rxhash = 0, act; + int buflen = hdr->buflen; + int ret = 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_init_buff(xdp, buflen, &tfile->xdp_rxq); + xdp_set_data_meta_invalid(xdp); + + act = bpf_prog_run_xdp(xdp_prog, xdp); + ret = tun_xdp_act(tun, xdp_prog, xdp, act); + if (ret < 0) { + put_page(virt_to_head_page(xdp->data)); + return ret; + } + + switch (ret) { + case XDP_REDIRECT: + *flush = true; + fallthrough; + 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) { + ret = -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))) { + atomic_long_inc(&tun->rx_frame_errors); + kfree_skb(skb); + ret = -EINVAL; + goto out; + } + + skb->protocol = eth_type_trans(skb, tun->dev); + skb_reset_network_header(skb); + skb_probe_transport_header(skb); + skb_record_rx_queue(skb, tfile->queue_index); + + if (skb_xdp) { + ret = do_xdp_generic(xdp_prog, skb); + if (ret != XDP_PASS) { + ret = 0; + goto out; + } + } + + if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 && + !tfile->detached) + rxhash = __skb_get_hash_symmetric(skb); + + if (tfile->napi_enabled) { + queue = &tfile->sk.sk_write_queue; + spin_lock(&queue->lock); + + if (unlikely(tfile->detached)) { + spin_unlock(&queue->lock); + kfree_skb(skb); + return -EBUSY; + } + + __skb_queue_tail(queue, skb); + spin_unlock(&queue->lock); + ret = 1; + } else { + netif_receive_skb(skb); + ret = 0; + } + + /* No need to disable preemption here since this function is + * always called with bh disabled + */ + dev_sw_netstats_rx_add(tun->dev, datasize); + + if (rxhash) + tun_flow_update(tun, rxhash, tfile); + +out: + return ret; +} + +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 (m->msg_controllen == sizeof(struct tun_msg_ctl) && + ctl && ctl->type == TUN_MSG_PTR) { + struct tun_page tpage; + int n = ctl->num; + int flush = 0, queued = 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]; + ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage); + if (ret > 0) + queued += ret; + } + + if (flush) + xdp_do_flush(); + + if (tfile->napi_enabled && queued > 0) + napi_schedule(&tfile->napi); + + 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_flags_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return sysfs_emit(buf, "0x%x\n", tun_flags(tun)); +} + +static ssize_t owner_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return uid_valid(tun->owner)? + sysfs_emit(buf, "%u\n", + from_kuid_munged(current_user_ns(), tun->owner)) : + sysfs_emit(buf, "-1\n"); +} + +static ssize_t group_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return gid_valid(tun->group) ? + sysfs_emit(buf, "%u\n", + from_kgid_munged(current_user_ns(), tun->group)) : + sysfs_emit(buf, "-1\n"); +} + +static DEVICE_ATTR_RO(tun_flags); +static DEVICE_ATTR_RO(owner); +static DEVICE_ATTR_RO(group); + +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, true); + 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; + 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; + + 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->ifr = ifr; + tun->file = file; + + tun_net_initialize(dev); + + err = register_netdevice(tun->dev); + if (err < 0) { + free_netdev(dev); + return err; + } + /* free_netdev() won't check refcnt, to avoid race + * with dev_put() we need publish tun after registration. + */ + rcu_assign_pointer(tfile->tun, tun); + } + + if (ifr->ifr_flags & IFF_NO_CARRIER) + netif_carrier_off(tun->dev); + else + netif_carrier_on(tun->dev); + + /* 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; +} + +static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr) +{ + 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, + tun->flags & IFF_NAPI_FRAGS, true); + } 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; + + if (ret >= 0) + netdev_state_change(tun->dev); + +unlock: + rtnl_unlock(); + return ret; +} + +static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **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); +} + +/* Return correct value for tun->dev->addr_len based on tun->dev->type. */ +static unsigned char tun_get_addr_len(unsigned short type) +{ + switch (type) { + case ARPHRD_IP6GRE: + case ARPHRD_TUNNEL6: + return sizeof(struct in6_addr); + case ARPHRD_IPGRE: + case ARPHRD_TUNNEL: + case ARPHRD_SIT: + return 4; + case ARPHRD_ETHER: + return ETH_ALEN; + case ARPHRD_IEEE802154: + case ARPHRD_IEEE802154_MONITOR: + return IEEE802154_EXTENDED_ADDR_LEN; + case ARPHRD_PHONET_PIPE: + case ARPHRD_PPP: + case ARPHRD_NONE: + return 0; + case ARPHRD_6LOWPAN: + return EUI64_ADDR_LEN; + case ARPHRD_FDDI: + return FDDI_K_ALEN; + case ARPHRD_HIPPI: + return HIPPI_ALEN; + case ARPHRD_IEEE802: + return FC_ALEN; + case ARPHRD_ROSE: + return ROSE_ADDR_LEN; + case ARPHRD_NETROM: + return AX25_ADDR_LEN; + case ARPHRD_LOCALTLK: + return LTALK_ALEN; + default: + return 0; + } +} + +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 net *net = sock_net(&tfile->sk); + struct tun_struct *tun; + void __user* argp = (void __user*)arg; + unsigned int carrier; + struct ifreq ifr; + kuid_t owner; + kgid_t group; + int ifindex; + int sndbuf; + int vnet_hdr_sz; + int le; + int ret; + bool do_notify = false; + + if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || + (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) { + 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 | IFF_NO_CARRIER | + TUN_FEATURES, (unsigned int __user*)argp); + } else if (cmd == TUNSETQUEUE) { + return tun_set_queue(file, &ifr); + } else if (cmd == SIOCGSKNS) { + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + return -EPERM; + return open_related_ns(&net->ns, get_net_ns); + } + + 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(net, 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 = -EINVAL; + if (ifindex < 0) + goto unlock; + ret = 0; + tfile->ifindex = ifindex; + goto unlock; + } + + ret = -EBADFD; + if (!tun) + goto unlock; + + netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd); + + net = dev_net(tun->dev); + ret = 0; + switch (cmd) { + case TUNGETIFF: + tun_get_iff(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] */ + netif_info(tun, drv, tun->dev, "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); + do_notify = true; + } + if (!arg && (tun->flags & IFF_PERSIST)) { + tun->flags &= ~IFF_PERSIST; + module_put(THIS_MODULE); + do_notify = true; + } + + netif_info(tun, drv, tun->dev, "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; + do_notify = true; + netif_info(tun, drv, tun->dev, "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; + do_notify = true; + netif_info(tun, drv, tun->dev, "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) { + netif_info(tun, drv, tun->dev, + "Linktype set failed because interface is up\n"); + ret = -EBUSY; + } else { + ret = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, + tun->dev); + ret = notifier_to_errno(ret); + if (ret) { + netif_info(tun, drv, tun->dev, + "Refused to change device type\n"); + break; + } + tun->dev->type = (int) arg; + tun->dev->addr_len = tun_get_addr_len(tun->dev->type); + netif_info(tun, drv, tun->dev, "linktype set to %d\n", + tun->dev->type); + call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, + tun->dev); + } + break; + + case TUNSETDEBUG: + tun->msg_enable = (u32)arg; + break; + + 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 */ + dev_get_mac_address(&ifr.ifr_hwaddr, net, tun->dev->name); + if (copy_to_user(argp, &ifr, ifreq_len)) + ret = -EFAULT; + break; + + case SIOCSIFHWADDR: + /* Set hw address */ + ret = dev_set_mac_address_user(tun->dev, &ifr.ifr_hwaddr, NULL); + 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; + + case TUNSETCARRIER: + ret = -EFAULT; + if (copy_from_user(&carrier, argp, sizeof(carrier))) + goto unlock; + + ret = tun_net_change_carrier(tun->dev, (bool)carrier); + break; + + case TUNGETDEVNETNS: + ret = -EPERM; + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + goto unlock; + ret = open_related_ns(&net->ns, get_net_ns); + break; + + default: + ret = -EINVAL; + break; + } + + if (do_notify) + netdev_state_change(tun->dev); + +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_TGID, 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; + + tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, + &tun_proto, 0); + if (!tfile) + return -ENOMEM; + if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) { + sk_free(&tfile->sk); + return -ENOMEM; + } + + mutex_init(&tfile->napi_mutex); + RCU_INIT_POINTER(tfile->tun, NULL); + tfile->flags = 0; + tfile->ifindex = 0; + + init_waitqueue_head(&tfile->socket.wq.wait); + + tfile->socket.file = file; + tfile->socket.ops = &tun_socket_ops; + + sock_init_data_uid(&tfile->socket, &tfile->sk, current_fsuid()); + + 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); + + 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(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 void tun_default_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; +} + +static int tun_get_link_ksettings(struct net_device *dev, + struct ethtool_link_ksettings *cmd) +{ + struct tun_struct *tun = netdev_priv(dev); + + memcpy(cmd, &tun->link_ksettings, sizeof(*cmd)); + return 0; +} + +static int tun_set_link_ksettings(struct net_device *dev, + const struct ethtool_link_ksettings *cmd) +{ + struct tun_struct *tun = netdev_priv(dev); + + memcpy(&tun->link_ksettings, cmd, sizeof(*cmd)); + return 0; +} + +static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) +{ + struct tun_struct *tun = netdev_priv(dev); + + strscpy(info->driver, DRV_NAME, sizeof(info->driver)); + strscpy(info->version, DRV_VERSION, sizeof(info->version)); + + switch (tun->flags & TUN_TYPE_MASK) { + case IFF_TUN: + strscpy(info->bus_info, "tun", sizeof(info->bus_info)); + break; + case IFF_TAP: + strscpy(info->bus_info, "tap", sizeof(info->bus_info)); + break; + } +} + +static u32 tun_get_msglevel(struct net_device *dev) +{ + struct tun_struct *tun = netdev_priv(dev); + + return tun->msg_enable; +} + +static void tun_set_msglevel(struct net_device *dev, u32 value) +{ + struct tun_struct *tun = netdev_priv(dev); + + tun->msg_enable = value; +} + +static int tun_get_coalesce(struct net_device *dev, + struct ethtool_coalesce *ec, + struct kernel_ethtool_coalesce *kernel_coal, + struct netlink_ext_ack *extack) +{ + 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 kernel_ethtool_coalesce *kernel_coal, + struct netlink_ext_ack *extack) +{ + 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 = { + .supported_coalesce_params = ETHTOOL_COALESCE_RX_MAX_FRAMES, + .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, + .set_link_ksettings = tun_set_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); + int i; + + 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; + case NETDEV_UP: + 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); + } + 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"); |