2 files changed, 174 insertions, 166 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 2693f883ecda..901551c8ca0e 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 563fae542da6..4c6307ad9fdb 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 */