diff options
| -rw-r--r-- | drivers/net/tun.c | 316 | ||||
| -rw-r--r-- | include/linux/if_tun.h | 24 |
2 files changed, 174 insertions, 166 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 2693f88..901551c 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -18,15 +18,11 @@ /* * Changes: * - * Brian Braunstein <linuxkernel@bristyle.com> 2007/03/23 - * Fixed hw address handling. Now net_device.dev_addr is kept consistent - * with tun.dev_addr when the address is set by this module. - * * Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14 * Add TUNSETLINK ioctl to set the link encapsulation * * Mark Smith <markzzzsmith@yahoo.com.au> - * Use random_ether_addr() for tap MAC address. + * Use random_ether_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. @@ -83,9 +79,16 @@ static int debug; #define DBG1( a... ) #endif +#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]; +}; + struct tun_struct { struct list_head list; - unsigned long flags; + unsigned int flags; int attached; uid_t owner; gid_t group; @@ -94,19 +97,119 @@ struct tun_struct { struct sk_buff_head readq; struct net_device *dev; + struct fasync_struct *fasync; - struct fasync_struct *fasync; - - unsigned long if_flags; - u8 dev_addr[ETH_ALEN]; - u32 chr_filter[2]; - u32 net_filter[2]; + struct tap_filter txflt; #ifdef TUN_DEBUG int debug; #endif }; +/* TAP filterting */ +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; + + /* The rest is hashed */ + memset(filter->mask, 0, sizeof(filter->mask)); + for (; n < uf.count; n++) + 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 (!compare_ether_addr(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 unsigned int tun_net_id; @@ -141,7 +244,12 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev) if (!tun->attached) goto drop; - /* Packet dropping */ + /* 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 (skb_queue_len(&tun->readq) >= dev->tx_queue_len) { if (!(tun->flags & TUN_ONE_QUEUE)) { /* Normal queueing mode. */ @@ -158,7 +266,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev) } } - /* Queue packet */ + /* Enqueue packet */ skb_queue_tail(&tun->readq, skb); dev->trans_start = jiffies; @@ -174,41 +282,14 @@ drop: return 0; } -/** Add the specified Ethernet address to this multicast filter. */ -static void -add_multi(u32* filter, const u8* addr) -{ - int bit_nr = ether_crc(ETH_ALEN, addr) >> 26; - filter[bit_nr >> 5] |= 1 << (bit_nr & 31); -} - -/** Remove the specified Ethernet addres from this multicast filter. */ -static void -del_multi(u32* filter, const u8* addr) +static void tun_net_mclist(struct net_device *dev) { - int bit_nr = ether_crc(ETH_ALEN, addr) >> 26; - filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31)); -} - -/** Update the list of multicast groups to which the network device belongs. - * This list is used to filter packets being sent from the character device to - * the network device. */ -static void -tun_net_mclist(struct net_device *dev) -{ - struct tun_struct *tun = netdev_priv(dev); - const struct dev_mc_list *mclist; - int i; - DECLARE_MAC_BUF(mac); - DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n", - dev->name, dev->mc_count); - memset(tun->chr_filter, 0, sizeof tun->chr_filter); - for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL; - i++, mclist = mclist->next) { - add_multi(tun->net_filter, mclist->dmi_addr); - DBG(KERN_DEBUG "%s: tun_net_mclist: %s\n", - dev->name, print_mac(mac, mclist->dmi_addr)); - } + /* + * 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. + */ + return; } #define MIN_MTU 68 @@ -244,13 +325,11 @@ static void tun_net_init(struct net_device *dev) case TUN_TAP_DEV: /* Ethernet TAP Device */ - dev->set_multicast_list = tun_net_mclist; - ether_setup(dev); - dev->change_mtu = tun_net_change_mtu; + dev->change_mtu = tun_net_change_mtu; + dev->set_multicast_list = tun_net_mclist; - /* random address already created for us by tun_set_iff, use it */ - memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) ); + random_ether_addr(dev->dev_addr); dev->tx_queue_len = TUN_READQ_SIZE; /* We prefer our own queue length */ break; @@ -486,7 +565,6 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, DECLARE_WAITQUEUE(wait, current); struct sk_buff *skb; ssize_t len, ret = 0; - DECLARE_MAC_BUF(mac); if (!tun) return -EBADFD; @@ -499,10 +577,6 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, add_wait_queue(&tun->read_wait, &wait); while (len) { - const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; - u8 addr[ ETH_ALEN]; - int bit_nr; - current->state = TASK_INTERRUPTIBLE; /* Read frames from the queue */ @@ -522,36 +596,9 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv, } netif_wake_queue(tun->dev); - /** Decide whether to accept this packet. This code is designed to - * behave identically to an Ethernet interface. Accept the packet if - * - we are promiscuous. - * - the packet is addressed to us. - * - the packet is broadcast. - * - the packet is multicast and - * - we are multicast promiscous. - * - we belong to the multicast group. - */ - skb_copy_from_linear_data(skb, addr, min_t(size_t, sizeof addr, - skb->len)); - bit_nr = ether_crc(sizeof addr, addr) >> 26; - if ((tun->if_flags & IFF_PROMISC) || - memcmp(addr, tun->dev_addr, sizeof addr) == 0 || - memcmp(addr, ones, sizeof addr) == 0 || - (((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) || - (addr[0] == 0x33 && addr[1] == 0x33)) && - ((tun->if_flags & IFF_ALLMULTI) || - (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) { - DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %s\n", - tun->dev->name, print_mac(mac, addr)); - ret = tun_put_user(tun, skb, (struct iovec *) iv, len); - kfree_skb(skb); - break; - } else { - DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n", - tun->dev->name, print_mac(mac, addr)); - kfree_skb(skb); - continue; - } + ret = tun_put_user(tun, skb, (struct iovec *) iv, len); + kfree_skb(skb); + break; } current->state = TASK_RUNNING; @@ -647,12 +694,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) tun = netdev_priv(dev); tun->dev = dev; tun->flags = flags; - /* Be promiscuous by default to maintain previous behaviour. */ - tun->if_flags = IFF_PROMISC; - /* Generate random Ethernet address. */ - *(__be16 *)tun->dev_addr = htons(0x00FF); - get_random_bytes(tun->dev_addr + sizeof(u16), 4); - memset(tun->chr_filter, 0, sizeof tun->chr_filter); + tun->txflt.count = 0; tun_net_init(dev); @@ -751,6 +793,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file, struct tun_struct *tun = file->private_data; void __user* argp = (void __user*)arg; struct ifreq ifr; + int ret; DECLARE_MAC_BUF(mac); if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89) @@ -826,9 +869,6 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file, break; case TUNSETLINK: - { - int ret; - /* Only allow setting the type when the interface is down */ rtnl_lock(); if (tun->dev->flags & IFF_UP) { @@ -842,94 +882,44 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file, } rtnl_unlock(); return ret; - } #ifdef TUN_DEBUG case TUNSETDEBUG: tun->debug = arg; break; #endif - case TUNSETOFFLOAD: - { - int ret; rtnl_lock(); ret = set_offload(tun->dev, arg); rtnl_unlock(); return ret; - } - case SIOCGIFFLAGS: - ifr.ifr_flags = tun->if_flags; - if (copy_to_user( argp, &ifr, sizeof ifr)) - return -EFAULT; - return 0; - - case SIOCSIFFLAGS: - /** Set the character device's interface flags. Currently only - * IFF_PROMISC and IFF_ALLMULTI are used. */ - tun->if_flags = ifr.ifr_flags; - DBG(KERN_INFO "%s: interface flags 0x%lx\n", - tun->dev->name, tun->if_flags); - return 0; + case TUNSETTXFILTER: + /* Can be set only for TAPs */ + if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV) + return -EINVAL; + rtnl_lock(); + ret = update_filter(&tun->txflt, (void *) __user arg); + rtnl_unlock(); + return ret; case SIOCGIFHWADDR: - /* Note: the actual net device's address may be different */ - memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr, - min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr)); - if (copy_to_user( argp, &ifr, sizeof ifr)) + /* Get hw addres */ + 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, sizeof ifr)) return -EFAULT; return 0; case SIOCSIFHWADDR: - { - /* try to set the actual net device's hw address */ - int ret; + /* Set hw address */ + DBG(KERN_DEBUG "%s: set hw address: %s\n", + tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data)); rtnl_lock(); ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr); rtnl_unlock(); - - if (ret == 0) { - /** Set the character device's hardware address. This is used when - * filtering packets being sent from the network device to the character - * device. */ - memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data, - min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr)); - DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n", - tun->dev->name, - tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2], - tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]); - } - - return ret; - } - - case SIOCADDMULTI: - /** Add the specified group to the character device's multicast filter - * list. */ - rtnl_lock(); - netif_tx_lock_bh(tun->dev); - add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data); - netif_tx_unlock_bh(tun->dev); - rtnl_unlock(); - - DBG(KERN_DEBUG "%s: add multi: %s\n", - tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data)); - return 0; - - case SIOCDELMULTI: - /** Remove the specified group from the character device's multicast - * filter list. */ - rtnl_lock(); - netif_tx_lock_bh(tun->dev); - del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data); - netif_tx_unlock_bh(tun->dev); - rtnl_unlock(); - - DBG(KERN_DEBUG "%s: del multi: %s\n", - tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data)); - return 0; + return ret; default: return -EINVAL; diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h index 563fae5..4c6307a 100644 --- a/include/linux/if_tun.h +++ b/include/linux/if_tun.h @@ -17,6 +17,7 @@ #define __IF_TUN_H #include <linux/types.h> +#include <linux/if_ether.h> /* Read queue size */ #define TUN_READQ_SIZE 500 @@ -42,7 +43,8 @@ #define TUNSETLINK _IOW('T', 205, int) #define TUNSETGROUP _IOW('T', 206, int) #define TUNGETFEATURES _IOR('T', 207, unsigned int) -#define TUNSETOFFLOAD _IOW('T', 208, unsigned int) +#define TUNSETOFFLOAD _IOW('T', 208, unsigned int) +#define TUNSETTXFILTER _IOW('T', 209, unsigned int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 @@ -57,10 +59,26 @@ #define TUN_F_TSO6 0x04 /* I can handle TSO for IPv6 packets */ #define TUN_F_TSO_ECN 0x08 /* I can handle TSO with ECN bits. */ +/* Protocol info prepended to the packets (when IFF_NO_PI is not set) */ +#define TUN_PKT_STRIP 0x0001 struct tun_pi { - unsigned short flags; + __u16 flags; __be16 proto; }; -#define TUN_PKT_STRIP 0x0001 + +/* + * Filter spec (used for SETXXFILTER ioctls) + * This stuff is applicable only to the TAP (Ethernet) devices. + * If the count is zero the filter is disabled and the driver accepts + * all packets (promisc mode). + * If the filter is enabled in order to accept broadcast packets + * broadcast addr must be explicitly included in the addr list. + */ +#define TUN_FLT_ALLMULTI 0x0001 /* Accept all multicast packets */ +struct tun_filter { + __u16 flags; /* TUN_FLT_ flags see above */ + __u16 count; /* Number of addresses */ + __u8 addr[0][ETH_ALEN]; +}; #endif /* __IF_TUN_H */ |
