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                         break;
 108                 }
 109                 rcu_read_unlock();
 110                 skb->skb_iif = _dev->ifindex;
 111
 112                 if (from & AT_EGRESS) {
 113                         dp->st_rx_frm_egr++;
 114                         dev_queue_xmit(skb);
 115                 } else if (from & AT_INGRESS) {
 116                         dp->st_rx_frm_ing++;
 117                         skb_pull(skb, skb->dev->hard_header_len);
 118                         netif_rx(skb);
 119                 } else
 120                         BUG();
 121         }
 122
 123         if (__netif_tx_trylock(txq)) {
 124                 dp->st_rxq_check++;
 125                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 126                         dp->tasklet_pending = 0;
 127                         if (netif_queue_stopped(_dev))
 128                                 netif_wake_queue(_dev);
 129                 } else {
 130                         dp->st_rxq_rsch++;
 131                         __netif_tx_unlock(txq);
 132                         goto resched;
 133                 }
 134                 __netif_tx_unlock(txq);
 135         } else {
 136 resched:
 137                 dp->tasklet_pending = 1;
 138                 tasklet_schedule(&dp->ifb_tasklet);
 139         }
 140
 141 }
 142
 143 static const struct net_device_ops ifb_netdev_ops = {
 144         .ndo_open       = ifb_open,
 145         .ndo_stop       = ifb_close,
 146         .ndo_start_xmit = ifb_xmit,
 147         .ndo_validate_addr = eth_validate_addr,
 148 };
 149
 150 static void ifb_setup(struct net_device *dev)
 151 {
 152         /* Initialize the device structure. */
 153         dev->destructor = free_netdev;
 154         dev->netdev_ops = &ifb_netdev_ops;
 155
 156         /* Fill in device structure with ethernet-generic values. */
 157         ether_setup(dev);
 158         dev->tx_queue_len = TX_Q_LIMIT;
 159
 160         dev->flags |= IFF_NOARP;
 161         dev->flags &= ~IFF_MULTICAST;
 162         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
 163         random_ether_addr(dev->dev_addr);
 164 }
 165
 166 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 167 {
 168         struct ifb_private *dp = netdev_priv(dev);
 169         struct net_device_stats *stats = &dev->stats;
 170         u32 from = G_TC_FROM(skb->tc_verd);
 171
 172         stats->rx_packets++;
 173         stats->rx_bytes+=skb->len;
 174
 175         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 176                 dev_kfree_skb(skb);
 177                 stats->rx_dropped++;
 178                 return NETDEV_TX_OK;
 179         }
 180
 181         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 182                 netif_stop_queue(dev);
 183         }
 184
 185         skb_queue_tail(&dp->rq, skb);
 186         if (!dp->tasklet_pending) {
 187                 dp->tasklet_pending = 1;
 188                 tasklet_schedule(&dp->ifb_tasklet);
 189         }
 190
 191         return NETDEV_TX_OK;
 192 }
 193
 194 static int ifb_close(struct net_device *dev)
 195 {
 196         struct ifb_private *dp = netdev_priv(dev);
 197
 198         tasklet_kill(&dp->ifb_tasklet);
 199         netif_stop_queue(dev);
 200         skb_queue_purge(&dp->rq);
 201         skb_queue_purge(&dp->tq);
 202         return 0;
 203 }
 204
 205 static int ifb_open(struct net_device *dev)
 206 {
 207         struct ifb_private *dp = netdev_priv(dev);
 208
 209         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 210         skb_queue_head_init(&dp->rq);
 211         skb_queue_head_init(&dp->tq);
 212         netif_start_queue(dev);
 213
 214         return 0;
 215 }
 216
 217 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 218 {
 219         if (tb[IFLA_ADDRESS]) {
 220                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 221                         return -EINVAL;
 222                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 223                         return -EADDRNOTAVAIL;
 224         }
 225         return 0;
 226 }
 227
 228 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 229         .kind           = "ifb",
 230         .priv_size      = sizeof(struct ifb_private),
 231         .setup          = ifb_setup,
 232         .validate       = ifb_validate,
 233 };
 234
 235 /* Number of ifb devices to be set up by this module. */
 236 module_param(numifbs, int, 0);
 237 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 238
 239 static int __init ifb_init_one(int index)
 240 {
 241         struct net_device *dev_ifb;
 242         int err;
 243
 244         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 245                                  "ifb%d", ifb_setup);
 246
 247         if (!dev_ifb)
 248                 return -ENOMEM;
 249
 250         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 251         if (err < 0)
 252                 goto err;
 253
 254         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 255         err = register_netdevice(dev_ifb);
 256         if (err < 0)
 257                 goto err;
 258
 259         return 0;
 260
 261 err:
 262         free_netdev(dev_ifb);
 263         return err;
 264 }
 265
 266 static int __init ifb_init_module(void)
 267 {
 268         int i, err;
 269
 270         rtnl_lock();
 271         err = __rtnl_link_register(&ifb_link_ops);
 272
 273         for (i = 0; i < numifbs && !err; i++)
 274                 err = ifb_init_one(i);
 275         if (err)
 276                 __rtnl_link_unregister(&ifb_link_ops);
 277         rtnl_unlock();
 278
 279         return err;
 280 }
 281
 282 static void __exit ifb_cleanup_module(void)
 283 {
 284         rtnl_link_unregister(&ifb_link_ops);
 285 }
 286
 287 module_init(ifb_init_module);
 288 module_exit(ifb_cleanup_module);
 289 MODULE_LICENSE("GPL");
 290 MODULE_AUTHOR("Jamal Hadi Salim");
 291 MODULE_ALIAS_RTNL_LINK("ifb");