drivers/net/ifb.c

   1 /* drivers/net/ifb.c:
   2
   3         The purpose of this driver is to provide a device that allows
   4         for sharing of resources:
   5
   6         1) qdiscs/policies that are per device as opposed to system wide.
   7         ifb allows for a device which can be redirected to thus providing
   8         an impression of sharing.
   9
  10         2) Allows for queueing incoming traffic for shaping instead of
  11         dropping.
  12
  13         The original concept is based on what is known as the IMQ
  14         driver initially written by Martin Devera, later rewritten
  15         by Patrick McHardy and then maintained by Andre Correa.
  16
  17         You need the tc action  mirror or redirect to feed this device
  18         packets.
  19
  20         This program is free software; you can redistribute it and/or
  21         modify it under the terms of the GNU General Public License
  22         as published by the Free Software Foundation; either version
  23         2 of the License, or (at your option) any later version.
  24
  25         Authors:        Jamal Hadi Salim (2005)
  26
  27 */
  28
  29
  30 #include <linux/module.h>
  31 #include <linux/kernel.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/etherdevice.h>
  34 #include <linux/init.h>
  35 #include <linux/moduleparam.h>
  36 #include <net/pkt_sched.h>
  37 #include <net/net_namespace.h>
  38
  39 #define TX_Q_LIMIT    32
  40 struct ifb_private {
  41         struct tasklet_struct   ifb_tasklet;
  42         int     tasklet_pending;
  43         struct sk_buff_head     rq;
  44         struct sk_buff_head     tq;
  45 };
  46
  47 static int numifbs = 2;
  48
  49 static void ri_tasklet(unsigned long dev);
  50 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  51 static int ifb_open(struct net_device *dev);
  52 static int ifb_close(struct net_device *dev);
  53
  54 static void ri_tasklet(unsigned long dev)
  55 {
  56
  57         struct net_device *_dev = (struct net_device *)dev;
  58         struct ifb_private *dp = netdev_priv(_dev);
  59         struct net_device_stats *stats = &_dev->stats;
  60         struct netdev_queue *txq;
  61         struct sk_buff *skb;
  62
  63         txq = netdev_get_tx_queue(_dev, 0);
  64         if ((skb = skb_peek(&dp->tq)) == NULL) {
  65                 if (__netif_tx_trylock(txq)) {
  66                         skb_queue_splice_tail_init(&dp->rq, &dp->tq);
  67                         __netif_tx_unlock(txq);
  68                 } else {
  69                         /* reschedule */
  70                         goto resched;
  71                 }
  72         }
  73
  74         while ((skb = __skb_dequeue(&dp->tq)) != NULL) {
  75                 u32 from = G_TC_FROM(skb->tc_verd);
  76
  77                 skb->tc_verd = 0;
  78                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  79                 stats->tx_packets++;
  80                 stats->tx_bytes +=skb->len;
  81
  82                 rcu_read_lock();
  83                 skb->dev = dev_get_by_index_rcu(&init_net, skb->skb_iif);
  84                 if (!skb->dev) {
  85                         rcu_read_unlock();
  86                         dev_kfree_skb(skb);
  87                         stats->tx_dropped++;
  88                         if (skb_queue_len(&dp->tq) != 0)
  89                                 goto resched;
  90                         break;
  91                 }
  92                 rcu_read_unlock();
  93                 skb->skb_iif = _dev->ifindex;
  94
  95                 if (from & AT_EGRESS) {
  96                         dev_queue_xmit(skb);
  97                 } else if (from & AT_INGRESS) {
  98                         skb_pull(skb, skb->dev->hard_header_len);
  99                         netif_receive_skb(skb);
 100                 } else
 101                         BUG();
 102         }
 103
 104         if (__netif_tx_trylock(txq)) {
 105                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 106                         dp->tasklet_pending = 0;
 107                         if (netif_queue_stopped(_dev))
 108                                 netif_wake_queue(_dev);
 109                 } else {
 110                         __netif_tx_unlock(txq);
 111                         goto resched;
 112                 }
 113                 __netif_tx_unlock(txq);
 114         } else {
 115 resched:
 116                 dp->tasklet_pending = 1;
 117                 tasklet_schedule(&dp->ifb_tasklet);
 118         }
 119
 120 }
 121
 122 static const struct net_device_ops ifb_netdev_ops = {
 123         .ndo_open       = ifb_open,
 124         .ndo_stop       = ifb_close,
 125         .ndo_start_xmit = ifb_xmit,
 126         .ndo_validate_addr = eth_validate_addr,
 127 };
 128
 129 #define IFB_FEATURES (NETIF_F_NO_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST  | \
 130                       NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6      | \
 131                       NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_TX)
 132
 133 static void ifb_setup(struct net_device *dev)
 134 {
 135         /* Initialize the device structure. */
 136         dev->destructor = free_netdev;
 137         dev->netdev_ops = &ifb_netdev_ops;
 138
 139         /* Fill in device structure with ethernet-generic values. */
 140         ether_setup(dev);
 141         dev->tx_queue_len = TX_Q_LIMIT;
 142
 143         dev->features |= IFB_FEATURES;
 144         dev->vlan_features |= IFB_FEATURES;
 145
 146         dev->flags |= IFF_NOARP;
 147         dev->flags &= ~IFF_MULTICAST;
 148         dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
 149         random_ether_addr(dev->dev_addr);
 150 }
 151
 152 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 153 {
 154         struct ifb_private *dp = netdev_priv(dev);
 155         struct net_device_stats *stats = &dev->stats;
 156         u32 from = G_TC_FROM(skb->tc_verd);
 157
 158         stats->rx_packets++;
 159         stats->rx_bytes+=skb->len;
 160
 161         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 162                 dev_kfree_skb(skb);
 163                 stats->rx_dropped++;
 164                 return NETDEV_TX_OK;
 165         }
 166
 167         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 168                 netif_stop_queue(dev);
 169         }
 170
 171         __skb_queue_tail(&dp->rq, skb);
 172         if (!dp->tasklet_pending) {
 173                 dp->tasklet_pending = 1;
 174                 tasklet_schedule(&dp->ifb_tasklet);
 175         }
 176
 177         return NETDEV_TX_OK;
 178 }
 179
 180 static int ifb_close(struct net_device *dev)
 181 {
 182         struct ifb_private *dp = netdev_priv(dev);
 183
 184         tasklet_kill(&dp->ifb_tasklet);
 185         netif_stop_queue(dev);
 186         __skb_queue_purge(&dp->rq);
 187         __skb_queue_purge(&dp->tq);
 188         return 0;
 189 }
 190
 191 static int ifb_open(struct net_device *dev)
 192 {
 193         struct ifb_private *dp = netdev_priv(dev);
 194
 195         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 196         __skb_queue_head_init(&dp->rq);
 197         __skb_queue_head_init(&dp->tq);
 198         netif_start_queue(dev);
 199
 200         return 0;
 201 }
 202
 203 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 204 {
 205         if (tb[IFLA_ADDRESS]) {
 206                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 207                         return -EINVAL;
 208                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 209                         return -EADDRNOTAVAIL;
 210         }
 211         return 0;
 212 }
 213
 214 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 215         .kind           = "ifb",
 216         .priv_size      = sizeof(struct ifb_private),
 217         .setup          = ifb_setup,
 218         .validate       = ifb_validate,
 219 };
 220
 221 /* Number of ifb devices to be set up by this module. */
 222 module_param(numifbs, int, 0);
 223 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 224
 225 static int __init ifb_init_one(int index)
 226 {
 227         struct net_device *dev_ifb;
 228         int err;
 229
 230         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 231                                  "ifb%d", ifb_setup);
 232
 233         if (!dev_ifb)
 234                 return -ENOMEM;
 235
 236         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 237         err = register_netdevice(dev_ifb);
 238         if (err < 0)
 239                 goto err;
 240
 241         return 0;
 242
 243 err:
 244         free_netdev(dev_ifb);
 245         return err;
 246 }
 247
 248 static int __init ifb_init_module(void)
 249 {
 250         int i, err;
 251
 252         rtnl_lock();
 253         err = __rtnl_link_register(&ifb_link_ops);
 254
 255         for (i = 0; i < numifbs && !err; i++)
 256                 err = ifb_init_one(i);
 257         if (err)
 258                 __rtnl_link_unregister(&ifb_link_ops);
 259         rtnl_unlock();
 260
 261         return err;
 262 }
 263
 264 static void __exit ifb_cleanup_module(void)
 265 {
 266         rtnl_link_unregister(&ifb_link_ops);
 267 }
 268
 269 module_init(ifb_init_module);
 270 module_exit(ifb_cleanup_module);
 271 MODULE_LICENSE("GPL");
 272 MODULE_AUTHOR("Jamal Hadi Salim");
 273 MODULE_ALIAS_RTNL_LINK("ifb");