diff options
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 2363 |
1 files changed, 2363 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c new file mode 100644 index 000000000..e470ae59d --- /dev/null +++ b/drivers/net/tun.c @@ -0,0 +1,2363 @@ +/* + * TUN - Universal TUN/TAP device driver. + * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ + */ + +/* + * Changes: + * + * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 + * Add TUNSETLINK ioctl to set the link encapsulation + * + * Mark Smith <markzzzsmith@yahoo.com.au> + * Use eth_random_addr() for tap MAC address. + * + * Harald Roelle <harald.roelle@ifi.lmu.de> 2004/04/20 + * Fixes in packet dropping, queue length setting and queue wakeup. + * Increased default tx queue length. + * Added ethtool API. + * Minor cleanups + * + * Daniel Podlejski <underley@underley.eu.org> + * Modifications for 2.3.99-pre5 kernel. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#define DRV_NAME "tun" +#define DRV_VERSION "1.6" +#define DRV_DESCRIPTION "Universal TUN/TAP device driver" +#define DRV_COPYRIGHT "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>" + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/major.h> +#include <linux/slab.h> +#include <linux/poll.h> +#include <linux/fcntl.h> +#include <linux/init.h> +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/miscdevice.h> +#include <linux/ethtool.h> +#include <linux/rtnetlink.h> +#include <linux/compat.h> +#include <linux/if.h> +#include <linux/if_arp.h> +#include <linux/if_ether.h> +#include <linux/if_tun.h> +#include <linux/if_vlan.h> +#include <linux/crc32.h> +#include <linux/nsproxy.h> +#include <linux/virtio_net.h> +#include <linux/rcupdate.h> +#include <net/net_namespace.h> +#include <net/netns/generic.h> +#include <net/rtnetlink.h> +#include <net/sock.h> +#include <linux/seq_file.h> +#include <linux/uio.h> + +#include <asm/uaccess.h> + +/* Uncomment to enable debugging */ +/* #define TUN_DEBUG 1 */ + +#ifdef TUN_DEBUG +static int debug; + +#define tun_debug(level, tun, fmt, args...) \ +do { \ + if (tun->debug) \ + netdev_printk(level, tun->dev, fmt, ##args); \ +} while (0) +#define DBG1(level, fmt, args...) \ +do { \ + if (debug == 2) \ + printk(level fmt, ##args); \ +} while (0) +#else +#define tun_debug(level, tun, fmt, args...) \ +do { \ + if (0) \ + netdev_printk(level, tun->dev, fmt, ##args); \ +} while (0) +#define DBG1(level, fmt, args...) \ +do { \ + if (0) \ + printk(level fmt, ##args); \ +} while (0) +#endif + +/* 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_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ + IFF_MULTI_QUEUE) +#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 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|NETIF_F_UFO) + + 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 u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) +{ + return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); +} + +static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) +{ + return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); +} + +static inline u32 tun_hashfn(u32 rxhash) +{ + return rxhash & 0x3ff; +} + +static struct tun_flow_entry *tun_flow_find(struct hlist_head *head, u32 rxhash) +{ + struct tun_flow_entry *e; + + hlist_for_each_entry_rcu(e, head, hash_link) { + if (e->rxhash == rxhash) + return e; + } + return NULL; +} + +static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun, + struct hlist_head *head, + u32 rxhash, u16 queue_index) +{ + struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC); + + if (e) { + tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n", + rxhash, queue_index); + e->updated = jiffies; + e->rxhash = rxhash; + e->rps_rxhash = 0; + e->queue_index = queue_index; + e->tun = tun; + hlist_add_head_rcu(&e->hash_link, head); + ++tun->flow_count; + } + return e; +} + +static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e) +{ + tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n", + e->rxhash, e->queue_index); + hlist_del_rcu(&e->hash_link); + kfree_rcu(e, rcu); + --tun->flow_count; +} + +static void tun_flow_flush(struct tun_struct *tun) +{ + int i; + + spin_lock_bh(&tun->lock); + for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { + struct tun_flow_entry *e; + struct hlist_node *n; + + hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) + tun_flow_delete(tun, e); + } + spin_unlock_bh(&tun->lock); +} + +static void tun_flow_delete_by_queue(struct tun_struct *tun, u16 queue_index) +{ + int i; + + spin_lock_bh(&tun->lock); + for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) { + struct tun_flow_entry *e; + struct hlist_node *n; + + hlist_for_each_entry_safe(e, n, &tun->flows[i], hash_link) { + if (e->queue_index == queue_index) + tun_flow_delete(tun, e); + } + } + spin_unlock_bh(&tun->lock); +} + +static void tun_flow_cleanup(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)) + 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 & IFF_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 & IFF_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 & 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)) { + 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 IFF_TUN: + dev->netdev_ops = &tun_netdev_ops; + + /* Point-to-Point TUN Device */ + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->mtu = 1500; + + /* Zero header length */ + dev->type = ARPHRD_NONE; + dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; + dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ + 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); + + 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 & IFF_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 & IFF_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) && + 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, tun->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 (!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); + } + + 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, tun16_to_cpu(tun, gso.csum_start), + tun16_to_cpu(tun, gso.csum_offset))) { + tun->dev->stats.rx_frame_errors++; + kfree_skb(skb); + return -EINVAL; + } + } + + switch (tun->flags & TUN_TYPE_MASK) { + case IFF_TUN: + if (tun->flags & IFF_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 IFF_TAP: + skb->protocol = eth_type_trans(skb, tun->dev); + break; + } + + 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: + skb_shinfo(skb)->gso_type = SKB_GSO_UDP; + 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 = tun16_to_cpu(tun, 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_reset_network_header(skb); + 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 (skb_vlan_tag_present(skb)) + vlan_hlen = VLAN_HLEN; + + if (tun->flags & IFF_VNET_HDR) + vnet_hdr_sz = 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 = { 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 = cpu_to_tun16(tun, skb_headlen(skb)); + gso.gso_size = cpu_to_tun16(tun, 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 if (sinfo->gso_type & SKB_GSO_UDP) + gso.gso_type = VIRTIO_NET_HDR_GSO_UDP; + else { + 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 (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 = cpu_to_tun16(tun, skb_checksum_start_offset(skb) + + vlan_hlen); + gso.csum_offset = cpu_to_tun16(tun, 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(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: + 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 err; + + ret = tun_put_user(tun, tfile, skb, to); + if (unlikely(ret < 0)) + kfree_skb(skb); + else + consume_skb(skb); + + return ret; +} + +static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct tun_file *tfile = file->private_data; + struct tun_struct *tun = __tun_get(tfile); + ssize_t len = iov_iter_count(to), ret; + + if (!tun) + return -EBADFD; + ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK); + 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 socket *sock, struct msghdr *m, size_t total_len) +{ + int ret; + struct tun_file *tfile = container_of(sock, struct tun_file, socket); + struct tun_struct *tun = __tun_get(tfile); + + if (!tun) + return -EBADFD; + + ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter, + m->msg_flags & MSG_DONTWAIT); + 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); + 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; + } + ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT); + if (ret > (ssize_t)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) +{ + return tun->flags & (TUN_FEATURES | IFF_PERSIST | IFF_TUN | IFF_TAP); +} + +static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return sprintf(buf, "0x%x\n", tun_flags(tun)); +} + +static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return uid_valid(tun->owner)? + sprintf(buf, "%u\n", + from_kuid_munged(current_user_ns(), tun->owner)): + sprintf(buf, "-1\n"); +} + +static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct tun_struct *tun = netdev_priv(to_net_dev(dev)); + return gid_valid(tun->group) ? + sprintf(buf, "%u\n", + from_kgid_munged(current_user_ns(), tun->group)): + sprintf(buf, "-1\n"); +} + +static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL); +static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL); +static DEVICE_ATTR(group, 0444, tun_show_group, NULL); + +static struct attribute *tun_dev_attrs[] = { + &dev_attr_tun_flags.attr, + &dev_attr_owner.attr, + &dev_attr_group.attr, + NULL +}; + +static const struct attribute_group tun_attr_group = { + .attrs = tun_dev_attrs +}; + +static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) +{ + struct tun_struct *tun; + struct tun_file *tfile = file->private_data; + struct net_device *dev; + int err; + + if (tfile->detached) + return -EINVAL; + + 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); + if (err < 0) + return err; + + if (tun->flags & IFF_MULTI_QUEUE && + (tun->numqueues + tun->numdisabled > 1)) { + /* One or more queue has already been attached, no need + * to initialize the device again. + */ + return 0; + } + } + else { + char *name; + unsigned long flags = 0; + int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ? + MAX_TAP_QUEUES : 1; + + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + return -EPERM; + err = security_tun_dev_create(); + if (err < 0) + return err; + + /* Set dev type */ + if (ifr->ifr_flags & IFF_TUN) { + /* TUN device */ + flags |= IFF_TUN; + name = "tun%d"; + } else if (ifr->ifr_flags & IFF_TAP) { + /* TAP device */ + flags |= IFF_TAP; + name = "tap%d"; + } else + return -EINVAL; + + if (*ifr->ifr_name) + name = ifr->ifr_name; + + dev = alloc_netdev_mqs(sizeof(struct tun_struct), name, + NET_NAME_UNKNOWN, tun_setup, queues, + queues); + + if (!dev) + return -ENOMEM; + + 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->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; + } + + netif_carrier_on(tun->dev); + + tun_debug(KERN_INFO, tun, "tun_set_iff\n"); + + tun->flags = (tun->flags & ~TUN_FEATURES) | + (ifr->ifr_flags & TUN_FEATURES); + + /* Make sure persistent devices do not get stuck in + * xoff state. + */ + if (netif_running(tun->dev)) + netif_tx_wake_all_queues(tun->dev); + + strcpy(ifr->ifr_name, tun->dev->name); + return 0; + +err_detach: + tun_detach_all(dev); +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); + } + + if (arg & TUN_F_UFO) { + features |= NETIF_F_UFO; + 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; + 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 & IFF_MULTI_QUEUE) || 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 le; + 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 | TUN_FEATURES, + (unsigned int __user*)argp); + } else if (cmd == TUNSETQUEUE) + return tun_set_queue(file, &ifr); + + ret = 0; + rtnl_lock(); + + tun = __tun_get(tfile); + if (cmd == TUNSETIFF && !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 & IFF_PERSIST)) { + tun->flags |= IFF_PERSIST; + __module_get(THIS_MODULE); + } + if (!arg && (tun->flags & IFF_PERSIST)) { + tun->flags &= ~IFF_PERSIST; + module_put(THIS_MODULE); + } + + tun_debug(KERN_INFO, tun, "persist %s\n", + arg ? "enabled" : "disabled"); + break; + + case TUNSETOWNER: + /* Set owner of the device */ + owner = make_kuid(current_user_ns(), arg); + if (!uid_valid(owner)) { + ret = -EINVAL; + break; + } + tun->owner = owner; + tun_debug(KERN_INFO, tun, "owner set to %u\n", + from_kuid(&init_user_ns, tun->owner)); + break; + + case TUNSETGROUP: + /* Set group of the device */ + group = make_kgid(current_user_ns(), arg); + if (!gid_valid(group)) { + ret = -EINVAL; + break; + } + tun->group = group; + tun_debug(KERN_INFO, tun, "group set to %u\n", + from_kgid(&init_user_ns, tun->group)); + break; + + case TUNSETLINK: + /* Only allow setting the type when the interface is down */ + if (tun->dev->flags & IFF_UP) { + tun_debug(KERN_INFO, tun, + "Linktype set failed because interface is up\n"); + ret = -EBUSY; + } else { + tun->dev->type = (int) arg; + tun_debug(KERN_INFO, tun, "linktype set to %d\n", + tun->dev->type); + ret = 0; + } + break; + +#ifdef TUN_DEBUG + case TUNSETDEBUG: + tun->debug = arg; + break; +#endif + case TUNSETOFFLOAD: + ret = set_offload(tun, arg); + break; + + case TUNSETTXFILTER: + /* Can be set only for TAPs */ + ret = -EINVAL; + if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP) + break; + ret = update_filter(&tun->txflt, (void __user *)arg); + break; + + case SIOCGIFHWADDR: + /* Get hw address */ + memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN); + ifr.ifr_hwaddr.sa_family = tun->dev->type; + if (copy_to_user(argp, &ifr, ifreq_len)) + ret = -EFAULT; + break; + + case SIOCSIFHWADDR: + /* Set hw address */ + tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n", + ifr.ifr_hwaddr.sa_data); + + ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); + break; + + case TUNGETSNDBUF: + sndbuf = tfile->socket.sk->sk_sndbuf; + if (copy_to_user(argp, &sndbuf, sizeof(sndbuf))) + ret = -EFAULT; + break; + + case TUNSETSNDBUF: + if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) { + ret = -EFAULT; + break; + } + + 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 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; + + 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 void 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); + + seq_printf(m, "iff:\t%s\n", ifr.ifr_name); +} +#endif + +static const struct file_operations tun_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read_iter = tun_chr_read_iter, + .write_iter = tun_chr_write_iter, + .poll = tun_chr_poll, + .unlocked_ioctl = tun_chr_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = tun_chr_compat_ioctl, +#endif + .open = tun_chr_open, + .release = tun_chr_close, + .fasync = tun_chr_fasync, +#ifdef CONFIG_PROC_FS + .show_fdinfo = tun_chr_show_fdinfo, +#endif +}; + +static struct miscdevice tun_miscdev = { + .minor = TUN_MINOR, + .name = "tun", + .nodename = "net/tun", + .fops = &tun_fops, +}; + +/* ethtool interface */ + +static int tun_get_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 IFF_TUN: + strlcpy(info->bus_info, "tun", sizeof(info->bus_info)); + break; + case IFF_TAP: + strlcpy(info->bus_info, "tap", sizeof(info->bus_info)); + break; + } +} + +static u32 tun_get_msglevel(struct net_device *dev) +{ +#ifdef TUN_DEBUG + struct tun_struct *tun = netdev_priv(dev); + return tun->debug; +#else + return -EOPNOTSUPP; +#endif +} + +static void tun_set_msglevel(struct net_device *dev, u32 value) +{ +#ifdef TUN_DEBUG + struct tun_struct *tun = netdev_priv(dev); + tun->debug = value; +#endif +} + +static 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"); |