/* * TUN - Universal TUN/TAP device driver. * Copyright (C) 1999-2002 Maxim Krasnyansky * * 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 2005/08/14 * Add TUNSETLINK ioctl to set the link encapsulation * * Mark Smith * Use eth_random_addr() for tap MAC address. * * Harald Roelle 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 * 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 " #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 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]; }; /* DEFAULT_MAX_NUM_RSS_QUEUES were chosen to let the rx/tx queues allocated for * the netdevice to be fit in one page. So we can make sure the success of * memory allocation. TODO: increase the limit. */ #define MAX_TAP_QUEUES DEFAULT_MAX_NUM_RSS_QUEUES #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 socket_wq wq; struct tun_struct __rcu *tun; struct net *net; struct fasync_struct *fasync; /* only used for fasnyc */ unsigned int flags; union { u16 queue_index; unsigned int ifindex; }; struct list_head next; struct tun_struct *detached; }; struct tun_flow_entry { struct hlist_node hash_link; struct rcu_head rcu; struct tun_struct *tun; u32 rxhash; u32 rps_rxhash; int queue_index; unsigned long updated; }; #define TUN_NUM_FLOW_ENTRIES 1024 /* 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 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; }; static inline u32 tun_hashfn(u32 rxhash) { return rxhash & 0x3ff; } static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) { struct tun_flow_entry *e; hlist_for_each_entry_rcu(e, head, hash_link) { if (e->rxhash == rxhash) return e; } return NULL; } static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, struct hlist_head *head, u32 rxhash, u16 queue_index) { struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); if (e) { tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", rxhash, queue_index); e->updated = jiffies; e->rxhash = rxhash; e->rps_rxhash = 0; e->queue_index = queue_index; e->tun = tun; hlist_add_head_rcu(&e->hash_link, head); ++tun->flow_count; } return e; } static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) { tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", e->rxhash, e->queue_index); sock_rps_reset_flow_hash(e->rps_rxhash); 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(unsigned long data) { struct tun_struct *tun = (struct tun_struct *)data; 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_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) { unsigned long this_timer; count++; this_timer = e->updated + delay; if (time_before_eq(this_timer, jiffies)) tun_flow_delete(tun, e); else 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_bh(&tun->lock); } static void tun_flow_update(struct tun_struct *tun, u32 rxhash, struct tun_file *tfile) { struct hlist_head *head; struct tun_flow_entry *e; unsigned long delay = tun->ageing_time; u16 queue_index = tfile->queue_index; if (!rxhash) return; else head = &tun->flows[tun_hashfn(rxhash)]; rcu_read_lock(); /* We may get a very small possibility of OOO during switching, not * worth to optimize.*/ if (tun->numqueues == 1 || tfile->detached) goto unlock; e = tun_flow_find(head, rxhash); if (likely(e)) { /* TODO: keep queueing to old queue until it's empty? */ e->queue_index = queue_index; e->updated = jiffies; sock_rps_record_flow_hash(e->rps_rxhash); } else { spin_lock_bh(&tun->lock); if (!tun_flow_find(head, rxhash) && tun->flow_count < MAX_TAP_FLOWS) tun_flow_create(tun, head, rxhash, queue_index); if (!timer_pending(&tun->flow_gc_timer)) mod_timer(&tun->flow_gc_timer, round_jiffies_up(jiffies + delay)); spin_unlock_bh(&tun->lock); } unlock: rcu_read_unlock(); } /** * Save the hash received in the stack receive path and update the * flow_hash table accordingly. */ static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash) { if (unlikely(e->rps_rxhash != hash)) { sock_rps_reset_flow_hash(e->rps_rxhash); e->rps_rxhash = hash; } } /* We try to identify a flow through its rxhash first. The reason that * we do not check rxq no. is because some cards(e.g 82599), chooses * the rxq based on the txq where the last packet of the flow comes. As * the userspace application move between processors, we may get a * different rxq no. here. If we could not get rxhash, then we would * hope the rxq no. may help here. */ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, void *accel_priv, select_queue_fallback_t fallback) { struct tun_struct *tun = netdev_priv(dev); struct tun_flow_entry *e; u32 txq = 0; u32 numqueues = 0; rcu_read_lock(); numqueues = ACCESS_ONCE(tun->numqueues); txq = skb_get_hash(skb); if (txq) { e = tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); if (e) { tun_flow_save_rps_rxhash(e, txq); txq = e->queue_index; } else /* use multiply and shift instead of expensive divide */ txq = ((u64)txq * numqueues) >> 32; } else if (likely(skb_rx_queue_recorded(skb))) { txq = skb_get_rx_queue(skb); while (unlikely(txq >= numqueues)) txq -= numqueues; } rcu_read_unlock(); return txq; } static inline bool tun_not_capable(struct tun_struct *tun) { const struct cred *cred = current_cred(); struct net *net = dev_net(tun->dev); return ((uid_valid(tun->owner) && !uid_eq(cred->euid, tun->owner)) || (gid_valid(tun->group) && !in_egroup_p(tun->group))) && !ns_capable(net->user_ns, CAP_NET_ADMIN); } static void tun_set_real_num_queues(struct tun_struct *tun) { netif_set_real_num_tx_queues(tun->dev, tun->numqueues); netif_set_real_num_rx_queues(tun->dev, tun->numqueues); } static void tun_disable_queue(struct tun_struct *tun, struct tun_file *tfile) { tfile->detached = tun; list_add_tail(&tfile->next, &tun->disabled); ++tun->numdisabled; } static struct tun_struct *tun_enable_queue(struct tun_file *tfile) { struct tun_struct *tun = tfile->detached; tfile->detached = NULL; list_del_init(&tfile->next); --tun->numdisabled; return tun; } static void tun_queue_purge(struct tun_file *tfile) { skb_queue_purge(&tfile->sk.sk_receive_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 && !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 & TUN_PERSIST) && tun->dev->reg_state == NETREG_REGISTERED) unregister_netdevice(tun->dev); } BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags)); sk_release_kernel(&tfile->sk); } } static void tun_detach(struct tun_file *tfile, bool clean) { rtnl_lock(); __tun_detach(tfile, clean); rtnl_unlock(); } static void tun_detach_all(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); struct tun_file *tfile, *tmp; int i, n = tun->numqueues; for (i = 0; i < n; i++) { tfile = rtnl_dereference(tun->tfiles[i]); BUG_ON(!tfile); 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_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]); /* Drop read queue */ tun_queue_purge(tfile); sock_put(&tfile->sk); } list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { tun_enable_queue(tfile); tun_queue_purge(tfile); sock_put(&tfile->sk); } BUG_ON(tun->numdisabled != 0); if (tun->flags & TUN_PERSIST) module_put(THIS_MODULE); } static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) { struct tun_file *tfile = file->private_data; 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 & TUN_TAP_MQ) && 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)) { err = sk_attach_filter(&tun->fprog, tfile->socket.sk); if (!err) goto out; } tfile->queue_index = tun->numqueues; rcu_assign_pointer(tfile->tun, tun); rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); tun->numqueues++; if (tfile->detached) tun_enable_queue(tfile); else sock_hold(&tfile->sk); tun_set_real_num_queues(tun); /* device is allowed to go away first, so no need to hold extra * refcnt. */ out: return err; } static struct tun_struct *__tun_get(struct tun_file *tfile) { struct tun_struct *tun; rcu_read_lock(); tun = rcu_dereference(tfile->tun); if (tun) dev_hold(tun->dev); rcu_read_unlock(); return tun; } static struct tun_struct *tun_get(struct file *file) { return __tun_get(file->private_data); } 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 = kmalloc(alen, GFP_KERNEL); if (!addr) return -ENOMEM; if (copy_from_user(addr, arg + sizeof(uf), alen)) { err = -EFAULT; goto done; } /* 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 done; } 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; done: 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) { 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 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; u32 numqueues = 0; rcu_read_lock(); tfile = rcu_dereference(tun->tfiles[txq]); numqueues = ACCESS_ONCE(tun->numqueues); /* Drop packet if interface is not attached */ if (txq >= numqueues) goto drop; if (numqueues == 1) { /* Select queue was not called for the skbuff, so we extract the * RPS hash and save it into the flow_table here. */ __u32 rxhash; rxhash = skb_get_hash(skb); if (rxhash) { struct tun_flow_entry *e; e = tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash); if (e) tun_flow_save_rps_rxhash(e, rxhash); } } 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; /* Limit the number of packets queued by dividing txq length with the * number of queues. */ if (skb_queue_len(&tfile->socket.sk->sk_receive_queue) * numqueues >= dev->tx_queue_len) goto drop; if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) goto drop; if (skb->sk) { sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags); sw_tx_timestamp(skb); } /* Orphan the skb - required as we might hang on to it * for indefinite time. */ skb_orphan(skb); nf_reset(skb); /* Enqueue packet */ skb_queue_tail(&tfile->socket.sk->sk_receive_queue, skb); /* 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->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. */ } #define MIN_MTU 68 #define MAX_MTU 65535 static int tun_net_change_mtu(struct net_device *dev, int new_mtu) { if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU) return -EINVAL; dev->mtu = new_mtu; return 0; } static netdev_features_t tun_net_fix_features(struct net_device *dev, netdev_features_t features) { struct tun_struct *tun = netdev_priv(dev); return (features & tun->set_features) | (features & ~TUN_USER_FEATURES); } #ifdef CONFIG_NET_POLL_CONTROLLER static void tun_poll_controller(struct net_device *dev) { /* * Tun only receives frames when: * 1) the char device endpoint gets data from user space * 2) the tun socket gets a sendmsg call from user space * Since both of those are synchronous operations, we are guaranteed * never to have pending data when we poll for it * so there is nothing to do here but return. * We need this though so netpoll recognizes us as an interface that * supports polling, which enables bridge devices in virt setups to * still use netconsole */ return; } #endif 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_change_mtu = tun_net_change_mtu, .ndo_fix_features = tun_net_fix_features, .ndo_select_queue = tun_select_queue, #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = tun_poll_controller, #endif }; 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_change_mtu = tun_net_change_mtu, .ndo_fix_features = tun_net_fix_features, .ndo_set_rx_mode = tun_net_mclist, .ndo_set_mac_address = eth_mac_addr, .ndo_validate_addr = eth_validate_addr, .ndo_select_queue = tun_select_queue, #ifdef CONFIG_NET_POLL_CONTROLLER .ndo_poll_controller = tun_poll_controller, #endif }; 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; setup_timer(&tun->flow_gc_timer, tun_flow_cleanup, (unsigned long)tun); 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); } /* 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 TUN_TUN_DEV: 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; dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ break; case TUN_TAP_DEV: 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); dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ break; } } /* Character device part */ /* Poll */ static unsigned int 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; unsigned int mask = 0; if (!tun) return POLLERR; sk = tfile->socket.sk; tun_debug(KERN_INFO, tun, "tun_chr_poll\n"); poll_wait(file, sk_sleep(sk), wait); if (!skb_queue_empty(&sk->sk_receive_queue)) mask |= POLLIN | POLLRDNORM; if (sock_writeable(sk) || (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) && sock_writeable(sk))) mask |= POLLOUT | POLLWRNORM; if (tun->dev->reg_state != NETREG_REGISTERED) mask = POLLERR; tun_put(tun); return mask; } /* 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; } /* 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) { 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 = NET_SKB_PAD, linear; struct virtio_net_hdr gso = { 0 }; int good_linear; int copylen; bool zerocopy = false; int err; u32 rxhash; ssize_t n; if (!(tun->flags & TUN_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; len -= sizeof(pi); n = copy_from_iter(&pi, sizeof(pi), from); if (n != sizeof(pi)) return -EFAULT; } if (tun->flags & TUN_VNET_HDR) { if (len < tun->vnet_hdr_sz) return -EINVAL; len -= tun->vnet_hdr_sz; n = copy_from_iter(&gso, sizeof(gso), from); if (n != sizeof(gso)) return -EFAULT; if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) gso.hdr_len = gso.csum_start + gso.csum_offset + 2; if (gso.hdr_len > len) return -EINVAL; iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); } if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { align += NET_IP_ALIGN; if (unlikely(len < ETH_HLEN || (gso.hdr_len && 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 ? 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 (!zerocopy) { copylen = len; if (gso.hdr_len > good_linear) linear = good_linear; else linear = gso.hdr_len; } skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); if (IS_ERR(skb)) { if (PTR_ERR(skb) != -EAGAIN) tun->dev->stats.rx_dropped++; 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 && msg_control) { struct ubuf_info *uarg = msg_control; uarg->callback(uarg, false); } } if (err) { tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EFAULT; } if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (!skb_partial_csum_set(skb, gso.csum_start, gso.csum_offset)) { tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } } switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: if (tun->flags & TUN_NO_PI) { switch (skb->data[0] & 0xf0) { case 0x40: pi.proto = htons(ETH_P_IP); break; case 0x60: pi.proto = htons(ETH_P_IPV6); break; default: tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EINVAL; } } skb_reset_mac_header(skb); skb->protocol = pi.proto; skb->dev = tun->dev; break; case TUN_TAP_DEV: skb->protocol = eth_type_trans(skb, tun->dev); break; } skb_reset_network_header(skb); if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) { pr_debug("GSO!\n"); switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; case VIRTIO_NET_HDR_GSO_UDP: { static bool warned; if (!warned) { warned = true; netdev_warn(tun->dev, "%s: using disabled UFO feature; please fix this program\n", current->comm); } skb_shinfo(skb)->gso_type = SKB_GSO_UDP; if (skb->protocol == htons(ETH_P_IPV6)) ipv6_proxy_select_ident(skb); break; } default: tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN) skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN; skb_shinfo(skb)->gso_size = gso.gso_size; if (skb_shinfo(skb)->gso_size == 0) { tun->dev->stats.rx_frame_errors++; kfree_skb(skb); return -EINVAL; } /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; } /* 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; } skb_probe_transport_header(skb, 0); rxhash = skb_get_hash(skb); netif_rx_ni(skb); tun->dev->stats.rx_packets++; tun->dev->stats.rx_bytes += len; 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_struct *tun = tun_get(file); struct tun_file *tfile = file->private_data; ssize_t result; if (!tun) return -EBADFD; result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK); tun_put(tun); return result; } /* 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 (vlan_tx_tag_present(skb)) vlan_hlen = VLAN_HLEN; if (tun->flags & TUN_VNET_HDR) vnet_hdr_sz = tun->vnet_hdr_sz; total = skb->len + vlan_hlen + vnet_hdr_sz; if (!(tun->flags & TUN_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 = { 0 }; /* no info leak */ if (iov_iter_count(iter) < vnet_hdr_sz) return -EINVAL; if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); /* This is a hint as to how much should be linear. */ gso.hdr_len = skb_headlen(skb); gso.gso_size = sinfo->gso_size; if (sinfo->gso_type & SKB_GSO_TCPV4) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (sinfo->gso_type & SKB_GSO_TCPV6) gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6; else { pr_err("unexpected GSO type: " "0x%x, gso_size %d, hdr_len %d\n", sinfo->gso_type, gso.gso_size, gso.hdr_len); print_hex_dump(KERN_ERR, "tun: ", DUMP_PREFIX_NONE, 16, 1, skb->head, min((int)gso.hdr_len, 64), true); WARN_ON_ONCE(1); return -EINVAL; } if (sinfo->gso_type & SKB_GSO_TCP_ECN) gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else gso.gso_type = VIRTIO_NET_HDR_GSO_NONE; if (skb->ip_summed == CHECKSUM_PARTIAL) { gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; gso.csum_start = skb_checksum_start_offset(skb) + vlan_hlen; gso.csum_offset = skb->csum_offset; } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { gso.flags = VIRTIO_NET_HDR_F_DATA_VALID; } /* else everything is zero */ 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 { __be16 h_vlan_proto; __be16 h_vlan_TCI; } veth; veth.h_vlan_proto = skb->vlan_proto; veth.h_vlan_TCI = htons(vlan_tx_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: tun->dev->stats.tx_packets++; tun->dev->stats.tx_bytes += skb->len + vlan_hlen; return total; } static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, struct iov_iter *to, int noblock) { struct sk_buff *skb; ssize_t ret; int peeked, err, off = 0; tun_debug(KERN_INFO, tun, "tun_do_read\n"); if (!iov_iter_count(to)) return 0; if (tun->dev->reg_state != NETREG_REGISTERED) return -EIO; /* Read frames from queue */ skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0, &peeked, &off, &err); if (!skb) return 0; ret = tun_put_user(tun, tfile, skb, to); kfree_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); ret = min_t(ssize_t, ret, len); if (ret > 0) iocb->ki_pos = ret; tun_put(tun); return ret; } static void tun_free_netdev(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); BUG_ON(!(list_empty(&tun->disabled))); tun_flow_uninit(tun); security_tun_dev_free_security(tun->security); free_netdev(dev); } static void tun_setup(struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); tun->owner = INVALID_UID; tun->group = INVALID_GID; dev->ethtool_ops = &tun_ethtool_ops; dev->destructor = tun_free_netdev; } /* Trivial set of netlink ops to allow deleting tun or tap * device with netlink. */ static int tun_validate(struct nlattr *tb[], struct nlattr *data[]) { return -EINVAL; } static struct rtnl_link_ops tun_link_ops __read_mostly = { .kind = DRV_NAME, .priv_size = sizeof(struct tun_struct), .setup = tun_setup, .validate = tun_validate, }; static void tun_sock_write_space(struct sock *sk) { struct tun_file *tfile; wait_queue_head_t *wqueue; if (!sock_writeable(sk)) return; if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) return; wqueue = sk_sleep(sk); if (wqueue && waitqueue_active(wqueue)) wake_up_interruptible_sync_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); tfile = container_of(sk, struct tun_file, sk); kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); } static int tun_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m, size_t total_len) { int ret; struct tun_file *tfile = container_of(sock, struct tun_file, socket); struct tun_struct *tun = __tun_get(tfile); struct iov_iter from; if (!tun) return -EBADFD; iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, total_len); ret = tun_get_user(tun, tfile, m->msg_control, &from, m->msg_flags & MSG_DONTWAIT); tun_put(tun); return ret; } static int tun_recvmsg(struct kiocb *iocb, 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); struct iov_iter to; int ret; if (!tun) return -EBADFD; if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) { ret = -EINVAL; goto out; } if (flags & MSG_ERRQUEUE) { ret = sock_recv_errqueue(sock->sk, m, total_len, SOL_PACKET, TUN_TX_TIMESTAMP); goto out; } iov_iter_init(&to, READ, m->msg_iov, m->msg_iovlen, total_len); ret = tun_do_read(tun, tfile, &to, flags & MSG_DONTWAIT); if (ret > total_len) { m->msg_flags |= MSG_TRUNC; ret = flags & MSG_TRUNC ? ret : total_len; } out: tun_put(tun); return ret; } static int tun_release(struct socket *sock) { if (sock->sk) sock_put(sock->sk); return 0; } /* Ops structure to mimic raw sockets with tun */ static const struct proto_ops tun_socket_ops = { .sendmsg = tun_sendmsg, .recvmsg = tun_recvmsg, .release = tun_release, }; static struct proto tun_proto = { .name = "tun", .owner = THIS_MODULE, .obj_size = sizeof(struct tun_file), }; static int tun_flags(struct tun_struct *tun) { int flags = 0; if (tun->flags & TUN_TUN_DEV) flags |= IFF_TUN; else flags |= IFF_TAP; if (tun->flags & TUN_NO_PI) flags |= IFF_NO_PI; /* This flag has no real effect. We track the value for backwards * compatibility. */ if (tun->flags & TUN_ONE_QUEUE) flags |= IFF_ONE_QUEUE; if (tun->flags & TUN_VNET_HDR) flags |= IFF_VNET_HDR; if (tun->flags & TUN_TAP_MQ) flags |= IFF_MULTI_QUEUE; if (tun->flags & TUN_PERSIST) flags |= IFF_PERSIST; return flags; } 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 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; 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 & TUN_TAP_MQ)) 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); if (err < 0) return err; if (tun->flags & TUN_TAP_MQ && (tun->numqueues + tun->numdisabled > 1)) { /* One or more queue has already been attached, no need * to initialize the device again. */ return 0; } } else { char *name; unsigned long flags = 0; int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? MAX_TAP_QUEUES : 1; if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) return -EPERM; err = security_tun_dev_create(); if (err < 0) return err; /* Set dev type */ if (ifr->ifr_flags & IFF_TUN) { /* TUN device */ flags |= TUN_TUN_DEV; name = "tun%d"; } else if (ifr->ifr_flags & IFF_TAP) { /* TAP device */ flags |= TUN_TAP_DEV; 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; tun = netdev_priv(dev); tun->dev = dev; tun->flags = flags; tun->txflt.count = 0; tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr); tun->filter_attached = false; tun->sndbuf = tfile->socket.sk->sk_sndbuf; spin_lock_init(&tun->lock); err = security_tun_dev_alloc_security(&tun->security); if (err < 0) goto err_free_dev; tun_net_init(dev); tun_flow_init(tun); dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX; dev->features = dev->hw_features; dev->vlan_features = dev->features & ~(NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX); INIT_LIST_HEAD(&tun->disabled); err = tun_attach(tun, file, false); if (err < 0) goto err_free_flow; err = register_netdevice(tun->dev); if (err < 0) goto err_detach; if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) || device_create_file(&tun->dev->dev, &dev_attr_owner) || device_create_file(&tun->dev->dev, &dev_attr_group)) pr_err("Failed to create tun sysfs files\n"); } netif_carrier_on(tun->dev); tun_debug(KERN_INFO, tun, "tun_set_iff\n"); if (ifr->ifr_flags & IFF_NO_PI) tun->flags |= TUN_NO_PI; else tun->flags &= ~TUN_NO_PI; /* This flag has no real effect. We track the value for backwards * compatibility. */ if (ifr->ifr_flags & IFF_ONE_QUEUE) tun->flags |= TUN_ONE_QUEUE; else tun->flags &= ~TUN_ONE_QUEUE; if (ifr->ifr_flags & IFF_VNET_HDR) tun->flags |= TUN_VNET_HDR; else tun->flags &= ~TUN_VNET_HDR; if (ifr->ifr_flags & IFF_MULTI_QUEUE) tun->flags |= TUN_TAP_MQ; else tun->flags &= ~TUN_TAP_MQ; /* Make sure persistent devices do not get stuck in * xoff state. */ if (netif_running(tun->dev)) netif_tx_wake_all_queues(tun->dev); strcpy(ifr->ifr_name, tun->dev->name); return 0; err_detach: tun_detach_all(dev); err_free_flow: tun_flow_uninit(tun); security_tun_dev_free_security(tun->security); err_free_dev: free_netdev(dev); return err; } static void tun_get_iff(struct net *net, struct tun_struct *tun, struct ifreq *ifr) { tun_debug(KERN_INFO, tun, "tun_get_iff\n"); strcpy(ifr->ifr_name, tun->dev->name); ifr->ifr_flags = tun_flags(tun); } /* This is like a cut-down ethtool ops, except done via tun fd so no * privs required. */ static int set_offload(struct tun_struct *tun, unsigned long arg) { netdev_features_t features = 0; if (arg & TUN_F_CSUM) { features |= NETIF_F_HW_CSUM; arg &= ~TUN_F_CSUM; if (arg & (TUN_F_TSO4|TUN_F_TSO6)) { if (arg & TUN_F_TSO_ECN) { features |= NETIF_F_TSO_ECN; arg &= ~TUN_F_TSO_ECN; } if (arg & TUN_F_TSO4) features |= NETIF_F_TSO; if (arg & TUN_F_TSO6) features |= NETIF_F_TSO6; arg &= ~(TUN_F_TSO4|TUN_F_TSO6); } } /* 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; 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]); sk_detach_filter(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]); ret = sk_attach_filter(&tun->fprog, 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); } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { tun = rtnl_dereference(tfile->tun); if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) ret = -EINVAL; else __tun_detach(tfile, false); } else ret = -EINVAL; unlock: rtnl_unlock(); return ret; } static long __tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg, int ifreq_len) { struct tun_file *tfile = file->private_data; struct tun_struct *tun; void __user* argp = (void __user*)arg; struct ifreq ifr; kuid_t owner; kgid_t group; int sndbuf; int vnet_hdr_sz; unsigned int ifindex; int ret; if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == 0x89) { 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_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | IFF_MULTI_QUEUE, (unsigned int __user*)argp); } else if (cmd == TUNSETQUEUE) return tun_set_queue(file, &ifr); ret = 0; rtnl_lock(); tun = __tun_get(tfile); if (cmd == TUNSETIFF && !tun) { ifr.ifr_name[IFNAMSIZ-1] = '\0'; ret = tun_set_iff(tfile->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 = 0; tfile->ifindex = ifindex; goto unlock; } ret = -EBADFD; if (!tun) goto unlock; tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd); ret = 0; switch (cmd) { case TUNGETIFF: tun_get_iff(current->nsproxy->net_ns, tun, &ifr); if (tfile->detached) ifr.ifr_flags |= IFF_DETACH_QUEUE; if (!tfile->socket.sk->sk_filter) ifr.ifr_flags |= IFF_NOFILTER; if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; case TUNSETNOCSUM: /* Disable/Enable checksum */ /* [unimplemented] */ tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n", arg ? "disabled" : "enabled"); break; case TUNSETPERSIST: /* Disable/Enable persist mode. Keep an extra reference to the * module to prevent the module being unprobed. */ if (arg && !(tun->flags & TUN_PERSIST)) { tun->flags |= TUN_PERSIST; __module_get(THIS_MODULE); } if (!arg && (tun->flags & TUN_PERSIST)) { tun->flags &= ~TUN_PERSIST; module_put(THIS_MODULE); } tun_debug(KERN_INFO, tun, "persist %s\n", arg ? "enabled" : "disabled"); break; case TUNSETOWNER: /* Set owner of the device */ owner = make_kuid(current_user_ns(), arg); if (!uid_valid(owner)) { ret = -EINVAL; break; } tun->owner = owner; tun_debug(KERN_INFO, tun, "owner set to %u\n", from_kuid(&init_user_ns, tun->owner)); break; case TUNSETGROUP: /* Set group of the device */ group = make_kgid(current_user_ns(), arg); if (!gid_valid(group)) { ret = -EINVAL; break; } tun->group = group; tun_debug(KERN_INFO, tun, "group set to %u\n", from_kgid(&init_user_ns, tun->group)); break; case TUNSETLINK: /* Only allow setting the type when the interface is down */ if (tun->dev->flags & IFF_UP) { tun_debug(KERN_INFO, tun, "Linktype set failed because interface is up\n"); ret = -EBUSY; } else { tun->dev->type = (int) arg; tun_debug(KERN_INFO, tun, "linktype set to %d\n", tun->dev->type); ret = 0; } break; #ifdef TUN_DEBUG case TUNSETDEBUG: tun->debug = arg; break; #endif case TUNSETOFFLOAD: ret = set_offload(tun, arg); break; case TUNSETTXFILTER: /* Can be set only for TAPs */ ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) break; ret = update_filter(&tun->txflt, (void __user *)arg); break; case SIOCGIFHWADDR: /* Get hw address */ memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); ifr.ifr_hwaddr.sa_family = tun->dev->type; if (copy_to_user(argp, &ifr, ifreq_len)) ret = -EFAULT; break; case SIOCSIFHWADDR: /* Set hw address */ tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", ifr.ifr_hwaddr.sa_data); ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); break; case TUNGETSNDBUF: sndbuf = tfile->socket.sk->sk_sndbuf; if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) ret = -EFAULT; break; case TUNSETSNDBUF: if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { ret = -EFAULT; break; } 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 TUNATTACHFILTER: /* Can be set only for TAPs */ ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) 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) != TUN_TAP_DEV) break; ret = 0; tun_detach_filter(tun, tun->numqueues); break; case TUNGETFILTER: ret = -EINVAL; if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) break; ret = -EFAULT; if (copy_to_user(argp, &tun->fprog, sizeof(tun->fprog))) break; ret = 0; break; default: ret = -EINVAL; break; } unlock: rtnl_unlock(); if (tun) tun_put(tun); return ret; } static long tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq)); } #ifdef CONFIG_COMPAT static long tun_chr_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch (cmd) { case TUNSETIFF: case TUNGETIFF: case TUNSETTXFILTER: case TUNGETSNDBUF: case TUNSETSNDBUF: case SIOCGIFHWADDR: case SIOCSIFHWADDR: arg = (unsigned long)compat_ptr(arg); break; default: arg = (compat_ulong_t)arg; break; } /* * compat_ifreq is shorter than ifreq, so we must not access beyond * the end of that structure. All fields that are used in this * driver are compatible though, we don't need to convert the * contents. */ return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq)); } #endif /* CONFIG_COMPAT */ static int tun_chr_fasync(int fd, struct file *file, int on) { struct tun_file *tfile = file->private_data; int ret; if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0) goto out; if (on) { __f_setown(file, task_pid(current), PIDTYPE_PID, 0); tfile->flags |= TUN_FASYNC; } else tfile->flags &= ~TUN_FASYNC; ret = 0; out: return ret; } static int tun_chr_open(struct inode *inode, struct file * file) { struct tun_file *tfile; DBG1(KERN_INFO, "tunX: tun_chr_open\n"); tfile = (struct tun_file *)sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto); if (!tfile) return -ENOMEM; RCU_INIT_POINTER(tfile->tun, NULL); tfile->net = get_net(current->nsproxy->net_ns); tfile->flags = 0; tfile->ifindex = 0; init_waitqueue_head(&tfile->wq.wait); RCU_INIT_POINTER(tfile->socket.wq, &tfile->wq); tfile->socket.file = file; tfile->socket.ops = &tun_socket_ops; sock_init_data(&tfile->socket, &tfile->sk); sk_change_net(&tfile->sk, tfile->net); tfile->sk.sk_write_space = tun_sock_write_space; tfile->sk.sk_sndbuf = INT_MAX; file->private_data = tfile; set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags); 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; struct net *net = tfile->net; tun_detach(tfile, true); put_net(net); return 0; } #ifdef CONFIG_PROC_FS static int tun_chr_show_fdinfo(struct seq_file *m, struct file *f) { struct tun_struct *tun; struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); rtnl_lock(); tun = tun_get(f); if (tun) tun_get_iff(current->nsproxy->net_ns, tun, &ifr); rtnl_unlock(); if (tun) tun_put(tun); return 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 = new_sync_read, .write = new_sync_write, .read_iter = tun_chr_read_iter, .write_iter = tun_chr_write_iter, .poll = tun_chr_poll, .unlocked_ioctl = tun_chr_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = tun_chr_compat_ioctl, #endif .open = tun_chr_open, .release = tun_chr_close, .fasync = tun_chr_fasync, #ifdef CONFIG_PROC_FS .show_fdinfo = tun_chr_show_fdinfo, #endif }; static struct miscdevice tun_miscdev = { .minor = TUN_MINOR, .name = "tun", .nodename = "net/tun", .fops = &tun_fops, }; /* ethtool interface */ static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd) { cmd->supported = 0; cmd->advertising = 0; ethtool_cmd_speed_set(cmd, SPEED_10); cmd->duplex = DUPLEX_FULL; cmd->port = PORT_TP; cmd->phy_address = 0; cmd->transceiver = XCVR_INTERNAL; cmd->autoneg = AUTONEG_DISABLE; cmd->maxtxpkt = 0; cmd->maxrxpkt = 0; return 0; } static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info) { struct tun_struct *tun = netdev_priv(dev); strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); strlcpy(info->version, DRV_VERSION, sizeof(info->version)); switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); break; case TUN_TAP_DEV: strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); break; } } static u32 tun_get_msglevel(struct net_device *dev) { #ifdef TUN_DEBUG struct tun_struct *tun = netdev_priv(dev); return tun->debug; #else return -EOPNOTSUPP; #endif } static void tun_set_msglevel(struct net_device *dev, u32 value) { #ifdef TUN_DEBUG struct tun_struct *tun = netdev_priv(dev); tun->debug = value; #endif } static const struct ethtool_ops tun_ethtool_ops = { .get_settings = tun_get_settings, .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, }; static int __init tun_init(void) { int ret = 0; pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION); pr_info("%s\n", DRV_COPYRIGHT); 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; } return 0; 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); } /* 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); 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");