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 #include <linux/lockdep.h>
  39
  40 #define TX_TIMEOUT  (2*HZ)
  41
  42 #define TX_Q_LIMIT    32
  43 struct ifb_private {
  44         struct tasklet_struct   ifb_tasklet;
  45         int     tasklet_pending;
  46         /* mostly debug stats leave in for now */
  47         unsigned long   st_task_enter; /* tasklet entered */
  48         unsigned long   st_txq_refl_try; /* transmit queue refill attempt */
  49         unsigned long   st_rxq_enter; /* receive queue entered */
  50         unsigned long   st_rx2tx_tran; /* receive to trasmit transfers */
  51         unsigned long   st_rxq_notenter; /*receiveQ not entered, resched */
  52         unsigned long   st_rx_frm_egr; /* received from egress path */
  53         unsigned long   st_rx_frm_ing; /* received from ingress path */
  54         unsigned long   st_rxq_check;
  55         unsigned long   st_rxq_rsch;
  56         struct sk_buff_head     rq;
  57         struct sk_buff_head     tq;
  58 };
  59
  60 static int numifbs = 2;
  61
  62 static void ri_tasklet(unsigned long dev);
  63 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  64 static int ifb_open(struct net_device *dev);
  65 static int ifb_close(struct net_device *dev);
  66
  67 static void ri_tasklet(unsigned long dev)
  68 {
  69
  70         struct net_device *_dev = (struct net_device *)dev;
  71         struct ifb_private *dp = netdev_priv(_dev);
  72         struct net_device_stats *stats = &_dev->stats;
  73         struct sk_buff *skb;
  74
  75         dp->st_task_enter++;
  76         if ((skb = skb_peek(&dp->tq)) == NULL) {
  77                 dp->st_txq_refl_try++;
  78                 if (netif_tx_trylock(_dev)) {
  79                         dp->st_rxq_enter++;
  80                         while ((skb = skb_dequeue(&dp->rq)) != NULL) {
  81                                 skb_queue_tail(&dp->tq, skb);
  82                                 dp->st_rx2tx_tran++;
  83                         }
  84                         netif_tx_unlock(_dev);
  85                 } else {
  86                         /* reschedule */
  87                         dp->st_rxq_notenter++;
  88                         goto resched;
  89                 }
  90         }
  91
  92         while ((skb = skb_dequeue(&dp->tq)) != NULL) {
  93                 u32 from = G_TC_FROM(skb->tc_verd);
  94
  95                 skb->tc_verd = 0;
  96                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  97                 stats->tx_packets++;
  98                 stats->tx_bytes +=skb->len;
  99
 100                 skb->dev = __dev_get_by_index(&init_net, skb->iif);
 101                 if (!skb->dev) {
 102                         dev_kfree_skb(skb);
 103                         stats->tx_dropped++;
 104                         break;
 105                 }
 106                 skb->iif = _dev->ifindex;
 107
 108                 if (from & AT_EGRESS) {
 109                         dp->st_rx_frm_egr++;
 110                         dev_queue_xmit(skb);
 111                 } else if (from & AT_INGRESS) {
 112                         dp->st_rx_frm_ing++;
 113                         skb_pull(skb, skb->dev->hard_header_len);
 114                         netif_rx(skb);
 115                 } else
 116                         BUG();
 117         }
 118
 119         if (netif_tx_trylock(_dev)) {
 120                 dp->st_rxq_check++;
 121                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 122                         dp->tasklet_pending = 0;
 123                         if (netif_queue_stopped(_dev))
 124                                 netif_wake_queue(_dev);
 125                 } else {
 126                         dp->st_rxq_rsch++;
 127                         netif_tx_unlock(_dev);
 128                         goto resched;
 129                 }
 130                 netif_tx_unlock(_dev);
 131         } else {
 132 resched:
 133                 dp->tasklet_pending = 1;
 134                 tasklet_schedule(&dp->ifb_tasklet);
 135         }
 136
 137 }
 138
 139 static void ifb_setup(struct net_device *dev)
 140 {
 141         /* Initialize the device structure. */
 142         dev->hard_start_xmit = ifb_xmit;
 143         dev->open = &ifb_open;
 144         dev->stop = &ifb_close;
 145         dev->destructor = free_netdev;
 146
 147         /* Fill in device structure with ethernet-generic values. */
 148         ether_setup(dev);
 149         dev->tx_queue_len = TX_Q_LIMIT;
 150         dev->change_mtu = NULL;
 151         dev->flags |= IFF_NOARP;
 152         dev->flags &= ~IFF_MULTICAST;
 153         random_ether_addr(dev->dev_addr);
 154 }
 155
 156 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 157 {
 158         struct ifb_private *dp = netdev_priv(dev);
 159         struct net_device_stats *stats = &dev->stats;
 160         int ret = 0;
 161         u32 from = G_TC_FROM(skb->tc_verd);
 162
 163         stats->rx_packets++;
 164         stats->rx_bytes+=skb->len;
 165
 166         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
 167                 dev_kfree_skb(skb);
 168                 stats->rx_dropped++;
 169                 return ret;
 170         }
 171
 172         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 173                 netif_stop_queue(dev);
 174         }
 175
 176         dev->trans_start = jiffies;
 177         skb_queue_tail(&dp->rq, skb);
 178         if (!dp->tasklet_pending) {
 179                 dp->tasklet_pending = 1;
 180                 tasklet_schedule(&dp->ifb_tasklet);
 181         }
 182
 183         return ret;
 184 }
 185
 186 static int ifb_close(struct net_device *dev)
 187 {
 188         struct ifb_private *dp = netdev_priv(dev);
 189
 190         tasklet_kill(&dp->ifb_tasklet);
 191         netif_stop_queue(dev);
 192         skb_queue_purge(&dp->rq);
 193         skb_queue_purge(&dp->tq);
 194         return 0;
 195 }
 196
 197 static int ifb_open(struct net_device *dev)
 198 {
 199         struct ifb_private *dp = netdev_priv(dev);
 200
 201         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 202         skb_queue_head_init(&dp->rq);
 203         skb_queue_head_init(&dp->tq);
 204         netif_start_queue(dev);
 205
 206         return 0;
 207 }
 208
 209 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 210 {
 211         if (tb[IFLA_ADDRESS]) {
 212                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 213                         return -EINVAL;
 214                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 215                         return -EADDRNOTAVAIL;
 216         }
 217         return 0;
 218 }
 219
 220 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 221         .kind           = "ifb",
 222         .priv_size      = sizeof(struct ifb_private),
 223         .setup          = ifb_setup,
 224         .validate       = ifb_validate,
 225 };
 226
 227 /* Number of ifb devices to be set up by this module. */
 228 module_param(numifbs, int, 0);
 229 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 230
 231 /*
 232  * dev_ifb->queue_lock is usually taken after dev->ingress_lock,
 233  * reversely to e.g. qdisc_lock_tree(). It should be safe until
 234  * ifb doesn't take dev->queue_lock with dev_ifb->ingress_lock.
 235  * But lockdep should know that ifb has different locks from dev.
 236  */
 237 static struct lock_class_key ifb_queue_lock_key;
 238 static struct lock_class_key ifb_ingress_lock_key;
 239
 240
 241 static int __init ifb_init_one(int index)
 242 {
 243         struct net_device *dev_ifb;
 244         int err;
 245
 246         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 247                                  "ifb%d", ifb_setup);
 248
 249         if (!dev_ifb)
 250                 return -ENOMEM;
 251
 252         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 253         if (err < 0)
 254                 goto err;
 255
 256         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 257         err = register_netdevice(dev_ifb);
 258         if (err < 0)
 259                 goto err;
 260
 261         lockdep_set_class(&dev_ifb->queue_lock, &ifb_queue_lock_key);
 262         lockdep_set_class(&dev_ifb->ingress_lock, &ifb_ingress_lock_key);
 263
 264         return 0;
 265
 266 err:
 267         free_netdev(dev_ifb);
 268         return err;
 269 }
 270
 271 static int __init ifb_init_module(void)
 272 {
 273         int i, err;
 274
 275         rtnl_lock();
 276         err = __rtnl_link_register(&ifb_link_ops);
 277
 278         for (i = 0; i < numifbs && !err; i++)
 279                 err = ifb_init_one(i);
 280         if (err)
 281                 __rtnl_link_unregister(&ifb_link_ops);
 282         rtnl_unlock();
 283
 284         return err;
 285 }
 286
 287 static void __exit ifb_cleanup_module(void)
 288 {
 289         rtnl_link_unregister(&ifb_link_ops);
 290 }
 291
 292 module_init(ifb_init_module);
 293 module_exit(ifb_cleanup_module);
 294 MODULE_LICENSE("GPL");
 295 MODULE_AUTHOR("Jamal Hadi Salim");
 296 MODULE_ALIAS_RTNL_LINK("ifb");