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                 skb->dev = __dev_get_by_index(&init_net, skb->iif);
 102                 if (!skb->dev) {
 103                         dev_kfree_skb(skb);
 104                         stats->tx_dropped++;
 105                         break;
 106                 }
 107                 skb->iif = _dev->ifindex;
 108
 109                 if (from & AT_EGRESS) {
 110                         dp->st_rx_frm_egr++;
 111                         dev_queue_xmit(skb);
 112                 } else if (from & AT_INGRESS) {
 113                         dp->st_rx_frm_ing++;
 114                         skb_pull(skb, skb->dev->hard_header_len);
 115                         netif_rx(skb);
 116                 } else
 117                         BUG();
 118         }
 119
 120         if (__netif_tx_trylock(txq)) {
 121                 dp->st_rxq_check++;
 122                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 123                         dp->tasklet_pending = 0;
 124                         if (netif_queue_stopped(_dev))
 125                                 netif_wake_queue(_dev);
 126                 } else {
 127                         dp->st_rxq_rsch++;
 128                         __netif_tx_unlock(txq);
 129                         goto resched;
 130                 }
 131                 __netif_tx_unlock(txq);
 132         } else {
 133 resched:
 134                 dp->tasklet_pending = 1;
 135                 tasklet_schedule(&dp->ifb_tasklet);
 136         }
 137
 138 }
 139
 140 static const struct net_device_ops ifb_netdev_ops = {
 141         .ndo_open       = ifb_open,
 142         .ndo_stop       = ifb_close,
 143         .ndo_start_xmit = ifb_xmit,
 144         .ndo_validate_addr = eth_validate_addr,
 145 };
 146
 147 static void ifb_setup(struct net_device *dev)
 148 {
 149         /* Initialize the device structure. */
 150         dev->destructor = free_netdev;
 151         dev->netdev_ops = &ifb_netdev_ops;
 152
 153         /* Fill in device structure with ethernet-generic values. */
 154         ether_setup(dev);
 155         dev->tx_queue_len = TX_Q_LIMIT;
 156
 157         dev->flags |= IFF_NOARP;
 158         dev->flags &= ~IFF_MULTICAST;
 159         dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
 160         random_ether_addr(dev->dev_addr);
 161 }
 162
 163 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 164 {
 165         struct ifb_private *dp = netdev_priv(dev);
 166         struct net_device_stats *stats = &dev->stats;
 167         u32 from = G_TC_FROM(skb->tc_verd);
 168
 169         stats->rx_packets++;
 170         stats->rx_bytes+=skb->len;
 171
 172         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
 173                 dev_kfree_skb(skb);
 174                 stats->rx_dropped++;
 175                 return NETDEV_TX_OK;
 176         }
 177
 178         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 179                 netif_stop_queue(dev);
 180         }
 181
 182         dev->trans_start = jiffies;
 183         skb_queue_tail(&dp->rq, skb);
 184         if (!dp->tasklet_pending) {
 185                 dp->tasklet_pending = 1;
 186                 tasklet_schedule(&dp->ifb_tasklet);
 187         }
 188
 189         return NETDEV_TX_OK;
 190 }
 191
 192 static int ifb_close(struct net_device *dev)
 193 {
 194         struct ifb_private *dp = netdev_priv(dev);
 195
 196         tasklet_kill(&dp->ifb_tasklet);
 197         netif_stop_queue(dev);
 198         skb_queue_purge(&dp->rq);
 199         skb_queue_purge(&dp->tq);
 200         return 0;
 201 }
 202
 203 static int ifb_open(struct net_device *dev)
 204 {
 205         struct ifb_private *dp = netdev_priv(dev);
 206
 207         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 208         skb_queue_head_init(&dp->rq);
 209         skb_queue_head_init(&dp->tq);
 210         netif_start_queue(dev);
 211
 212         return 0;
 213 }
 214
 215 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 216 {
 217         if (tb[IFLA_ADDRESS]) {
 218                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 219                         return -EINVAL;
 220                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 221                         return -EADDRNOTAVAIL;
 222         }
 223         return 0;
 224 }
 225
 226 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 227         .kind           = "ifb",
 228         .priv_size      = sizeof(struct ifb_private),
 229         .setup          = ifb_setup,
 230         .validate       = ifb_validate,
 231 };
 232
 233 /* Number of ifb devices to be set up by this module. */
 234 module_param(numifbs, int, 0);
 235 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 236
 237 static int __init ifb_init_one(int index)
 238 {
 239         struct net_device *dev_ifb;
 240         int err;
 241
 242         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 243                                  "ifb%d", ifb_setup);
 244
 245         if (!dev_ifb)
 246                 return -ENOMEM;
 247
 248         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 249         if (err < 0)
 250                 goto err;
 251
 252         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 253         err = register_netdevice(dev_ifb);
 254         if (err < 0)
 255                 goto err;
 256
 257         return 0;
 258
 259 err:
 260         free_netdev(dev_ifb);
 261         return err;
 262 }
 263
 264 static int __init ifb_init_module(void)
 265 {
 266         int i, err;
 267
 268         rtnl_lock();
 269         err = __rtnl_link_register(&ifb_link_ops);
 270
 271         for (i = 0; i < numifbs && !err; i++)
 272                 err = ifb_init_one(i);
 273         if (err)
 274                 __rtnl_link_unregister(&ifb_link_ops);
 275         rtnl_unlock();
 276
 277         return err;
 278 }
 279
 280 static void __exit ifb_cleanup_module(void)
 281 {
 282         rtnl_link_unregister(&ifb_link_ops);
 283 }
 284
 285 module_init(ifb_init_module);
 286 module_exit(ifb_cleanup_module);
 287 MODULE_LICENSE("GPL");
 288 MODULE_AUTHOR("Jamal Hadi Salim");
 289 MODULE_ALIAS_RTNL_LINK("ifb");