release/src-rt-6.x.4708/linux/linux-2.6.36/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_TIMEOUT  (2*HZ)
  40
  41 #define TX_Q_LIMIT    32
  42 struct ifb_private {
  43         struct tasklet_struct   ifb_tasklet;
  44         int     tasklet_pending;
  45         /* mostly debug stats leave in for now */
  46         unsigned long   st_task_enter; /* tasklet entered */
  47         unsigned long   st_txq_refl_try; /* transmit queue refill attempt */
  48         unsigned long   st_rxq_enter; /* receive queue entered */
  49         unsigned long   st_rx2tx_tran; /* receive to trasmit transfers */
  50         unsigned long   st_rxq_notenter; /*receiveQ not entered, resched */
  51         unsigned long   st_rx_frm_egr; /* received from egress path */
  52         unsigned long   st_rx_frm_ing; /* received from ingress path */
  53         unsigned long   st_rxq_check;
  54         unsigned long   st_rxq_rsch;
  55         struct sk_buff_head     rq;
  56         struct sk_buff_head     tq;
  57 };
  58
  59 static int numifbs = 2;
  60
  61 static void ri_tasklet(unsigned long dev);
  62 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  63 static int ifb_open(struct net_device *dev);
  64 static int ifb_close(struct net_device *dev);
  65
  66 static void ri_tasklet(unsigned long dev)
  67 {
  68
  69         struct net_device *_dev = (struct net_device *)dev;
  70         struct ifb_private *dp = netdev_priv(_dev);
  71         struct net_device_stats *stats = &_dev->stats;
  72         struct netdev_queue *txq;
  73         struct sk_buff *skb;
  74
  75         txq = netdev_get_tx_queue(_dev, 0);
  76         dp->st_task_enter++;
  77         if ((skb = skb_peek(&dp->tq)) == NULL) {
  78                 dp->st_txq_refl_try++;
  79                 if (__netif_tx_trylock(txq)) {
  80                         dp->st_rxq_enter++;
  81                         while ((skb = skb_dequeue(&dp->rq)) != NULL) {
  82                                 skb_queue_tail(&dp->tq, skb);
  83                                 dp->st_rx2tx_tran++;
  84                         }
  85                         __netif_tx_unlock(txq);
  86                 } else {
  87                         /* reschedule */
  88                         dp->st_rxq_notenter++;
  89                         goto resched;
  90                 }
  91         }
  92
  93         while ((skb = skb_dequeue(&dp->tq)) != NULL) {
  94                 u32 from = G_TC_FROM(skb->tc_verd);
  95
  96                 skb->tc_verd = 0;
  97                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  98                 stats->tx_packets++;
  99                 stats->tx_bytes +=skb->len;
 100
 101                 rcu_read_lock();
 102                 skb->dev = dev_get_by_index_rcu(&init_net, skb->skb_iif);
 103                 if (!skb->dev) {
 104                         rcu_read_unlock();
 105                         dev_kfree_skb(skb);
 106                         stats->tx_dropped++;
 107                         if (skb_queue_len(&dp->tq) != 0)
 108                                 goto resched;
 109                         break;
 110                 }
 111                 rcu_read_unlock();
 112                 skb->skb_iif = _dev->ifindex;
 113
 114                 if (from & AT_EGRESS) {
 115                         dp->st_rx_frm_egr++;
 116                         dev_queue_xmit(skb);
 117                 } else if (from & AT_INGRESS) {
 118                         dp->st_rx_frm_ing++;
 119                         skb_pull(skb, skb->dev->hard_header_len);
 120                         netif_rx(skb);
 121                 } else
 122                         BUG();
 123         }
 124
 125         if (__netif_tx_trylock(txq)) {
 126                 dp->st_rxq_check++;
 127                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 128                         dp->tasklet_pending = 0;
 129                         if (netif_queue_stopped(_dev))
 130                                 netif_wake_queue(_dev);
 131                 } else {
 132                         dp->st_rxq_rsch++;
 133                         __netif_tx_unlock(txq);
 134                         goto resched;
 135                 }
 136                 __netif_tx_unlock(txq);
 137         } else {
 138 resched:
 139                 dp->tasklet_pending = 1;
 140                 tasklet_schedule(&dp->ifb_tasklet);
 141         }
 142
 143 }
 144
 145 static const struct net_device_ops ifb_netdev_ops = {
 146         .ndo_open       = ifb_open,
 147         .ndo_stop       = ifb_close,
 148         .ndo_start_xmit = ifb_xmit,
 149         .ndo_validate_addr = eth_validate_addr,
 150 };
 151
 152 static void ifb_setup(struct net_device *dev)
 153 {
 154         /* Initialize the device structure. */
 155         dev->destructor = free_netdev;
 156         dev->netdev_ops = &ifb_netdev_ops;
 157
 158         /* Fill in device structure with ethernet-generic values. */
 159         ether_setup(dev);
 160         dev->tx_queue_len = TX_Q_LIMIT;
 161
 162         dev->flags |= IFF_NOARP;
 163         dev->flags &= ~IFF_MULTICAST;
 164         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
 165         random_ether_addr(dev->dev_addr);
 166 }
 167
 168 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 169 {
 170         struct ifb_private *dp = netdev_priv(dev);
 171         struct net_device_stats *stats = &dev->stats;
 172         u32 from = G_TC_FROM(skb->tc_verd);
 173
 174         stats->rx_packets++;
 175         stats->rx_bytes+=skb->len;
 176
 177         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 178                 dev_kfree_skb(skb);
 179                 stats->rx_dropped++;
 180                 return NETDEV_TX_OK;
 181         }
 182
 183         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 184                 netif_stop_queue(dev);
 185         }
 186
 187         skb_queue_tail(&dp->rq, skb);
 188         if (!dp->tasklet_pending) {
 189                 dp->tasklet_pending = 1;
 190                 tasklet_schedule(&dp->ifb_tasklet);
 191         }
 192
 193         return NETDEV_TX_OK;
 194 }
 195
 196 static int ifb_close(struct net_device *dev)
 197 {
 198         struct ifb_private *dp = netdev_priv(dev);
 199
 200         tasklet_kill(&dp->ifb_tasklet);
 201         netif_stop_queue(dev);
 202         skb_queue_purge(&dp->rq);
 203         skb_queue_purge(&dp->tq);
 204         return 0;
 205 }
 206
 207 static int ifb_open(struct net_device *dev)
 208 {
 209         struct ifb_private *dp = netdev_priv(dev);
 210
 211         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 212         skb_queue_head_init(&dp->rq);
 213         skb_queue_head_init(&dp->tq);
 214         netif_start_queue(dev);
 215
 216         return 0;
 217 }
 218
 219 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 220 {
 221         if (tb[IFLA_ADDRESS]) {
 222                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 223                         return -EINVAL;
 224                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 225                         return -EADDRNOTAVAIL;
 226         }
 227         return 0;
 228 }
 229
 230 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 231         .kind           = "ifb",
 232         .priv_size      = sizeof(struct ifb_private),
 233         .setup          = ifb_setup,
 234         .validate       = ifb_validate,
 235 };
 236
 237 /* Number of ifb devices to be set up by this module. */
 238 module_param(numifbs, int, 0);
 239 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 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         return 0;
 262
 263 err:
 264         free_netdev(dev_ifb);
 265         return err;
 266 }
 267
 268 static int __init ifb_init_module(void)
 269 {
 270         int i, err;
 271
 272         rtnl_lock();
 273         err = __rtnl_link_register(&ifb_link_ops);
 274
 275         for (i = 0; i < numifbs && !err; i++)
 276                 err = ifb_init_one(i);
 277         if (err)
 278                 __rtnl_link_unregister(&ifb_link_ops);
 279         rtnl_unlock();
 280
 281         return err;
 282 }
 283
 284 static void __exit ifb_cleanup_module(void)
 285 {
 286         rtnl_link_unregister(&ifb_link_ops);
 287 }
 288
 289 module_init(ifb_init_module);
 290 module_exit(ifb_cleanup_module);
 291 MODULE_LICENSE("GPL");
 292 MODULE_AUTHOR("Jamal Hadi Salim");
 293 MODULE_ALIAS_RTNL_LINK("ifb");