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         dev->trans_start = jiffies;
 186         skb_queue_tail(&dp->rq, skb);
 187         if (!dp->tasklet_pending) {
 188                 dp->tasklet_pending = 1;
 189                 tasklet_schedule(&dp->ifb_tasklet);
 190         }
 191
 192         return NETDEV_TX_OK;
 193 }
 194
 195 static int ifb_close(struct net_device *dev)
 196 {
 197         struct ifb_private *dp = netdev_priv(dev);
 198
 199         tasklet_kill(&dp->ifb_tasklet);
 200         netif_stop_queue(dev);
 201         skb_queue_purge(&dp->rq);
 202         skb_queue_purge(&dp->tq);
 203         return 0;
 204 }
 205
 206 static int ifb_open(struct net_device *dev)
 207 {
 208         struct ifb_private *dp = netdev_priv(dev);
 209
 210         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 211         skb_queue_head_init(&dp->rq);
 212         skb_queue_head_init(&dp->tq);
 213         netif_start_queue(dev);
 214
 215         return 0;
 216 }
 217
 218 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 219 {
 220         if (tb[IFLA_ADDRESS]) {
 221                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 222                         return -EINVAL;
 223                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 224                         return -EADDRNOTAVAIL;
 225         }
 226         return 0;
 227 }
 228
 229 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 230         .kind           = "ifb",
 231         .priv_size      = sizeof(struct ifb_private),
 232         .setup          = ifb_setup,
 233         .validate       = ifb_validate,
 234 };
 235
 236 /* Number of ifb devices to be set up by this module. */
 237 module_param(numifbs, int, 0);
 238 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 239
 240 static int __init ifb_init_one(int index)
 241 {
 242         struct net_device *dev_ifb;
 243         int err;
 244
 245         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 246                                  "ifb%d", ifb_setup);
 247
 248         if (!dev_ifb)
 249                 return -ENOMEM;
 250
 251         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 252         if (err < 0)
 253                 goto err;
 254
 255         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 256         err = register_netdevice(dev_ifb);
 257         if (err < 0)
 258                 goto err;
 259
 260         return 0;
 261
 262 err:
 263         free_netdev(dev_ifb);
 264         return err;
 265 }
 266
 267 static int __init ifb_init_module(void)
 268 {
 269         int i, err;
 270
 271         rtnl_lock();
 272         err = __rtnl_link_register(&ifb_link_ops);
 273
 274         for (i = 0; i < numifbs && !err; i++)
 275                 err = ifb_init_one(i);
 276         if (err)
 277                 __rtnl_link_unregister(&ifb_link_ops);
 278         rtnl_unlock();
 279
 280         return err;
 281 }
 282
 283 static void __exit ifb_cleanup_module(void)
 284 {
 285         rtnl_link_unregister(&ifb_link_ops);
 286 }
 287
 288 module_init(ifb_init_module);
 289 module_exit(ifb_cleanup_module);
 290 MODULE_LICENSE("GPL");
 291 MODULE_AUTHOR("Jamal Hadi Salim");
 292 MODULE_ALIAS_RTNL_LINK("ifb");