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 int 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 void ifb_setup(struct net_device *dev)
 141 {
 142         /* Initialize the device structure. */
 143         dev->hard_start_xmit = ifb_xmit;
 144         dev->open = &ifb_open;
 145         dev->stop = &ifb_close;
 146         dev->destructor = free_netdev;
 147
 148         /* Fill in device structure with ethernet-generic values. */
 149         ether_setup(dev);
 150         dev->tx_queue_len = TX_Q_LIMIT;
 151         dev->change_mtu = NULL;
 152         dev->flags |= IFF_NOARP;
 153         dev->flags &= ~IFF_MULTICAST;
 154         random_ether_addr(dev->dev_addr);
 155 }
 156
 157 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 158 {
 159         struct ifb_private *dp = netdev_priv(dev);
 160         struct net_device_stats *stats = &dev->stats;
 161         int ret = 0;
 162         u32 from = G_TC_FROM(skb->tc_verd);
 163
 164         stats->rx_packets++;
 165         stats->rx_bytes+=skb->len;
 166
 167         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
 168                 dev_kfree_skb(skb);
 169                 stats->rx_dropped++;
 170                 return ret;
 171         }
 172
 173         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 174                 netif_stop_queue(dev);
 175         }
 176
 177         dev->trans_start = jiffies;
 178         skb_queue_tail(&dp->rq, skb);
 179         if (!dp->tasklet_pending) {
 180                 dp->tasklet_pending = 1;
 181                 tasklet_schedule(&dp->ifb_tasklet);
 182         }
 183
 184         return ret;
 185 }
 186
 187 static int ifb_close(struct net_device *dev)
 188 {
 189         struct ifb_private *dp = netdev_priv(dev);
 190
 191         tasklet_kill(&dp->ifb_tasklet);
 192         netif_stop_queue(dev);
 193         skb_queue_purge(&dp->rq);
 194         skb_queue_purge(&dp->tq);
 195         return 0;
 196 }
 197
 198 static int ifb_open(struct net_device *dev)
 199 {
 200         struct ifb_private *dp = netdev_priv(dev);
 201
 202         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 203         skb_queue_head_init(&dp->rq);
 204         skb_queue_head_init(&dp->tq);
 205         netif_start_queue(dev);
 206
 207         return 0;
 208 }
 209
 210 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 211 {
 212         if (tb[IFLA_ADDRESS]) {
 213                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 214                         return -EINVAL;
 215                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 216                         return -EADDRNOTAVAIL;
 217         }
 218         return 0;
 219 }
 220
 221 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 222         .kind           = "ifb",
 223         .priv_size      = sizeof(struct ifb_private),
 224         .setup          = ifb_setup,
 225         .validate       = ifb_validate,
 226 };
 227
 228 /* Number of ifb devices to be set up by this module. */
 229 module_param(numifbs, int, 0);
 230 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 231
 232 static int __init ifb_init_one(int index)
 233 {
 234         struct net_device *dev_ifb;
 235         int err;
 236
 237         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 238                                  "ifb%d", ifb_setup);
 239
 240         if (!dev_ifb)
 241                 return -ENOMEM;
 242
 243         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 244         if (err < 0)
 245                 goto err;
 246
 247         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 248         err = register_netdevice(dev_ifb);
 249         if (err < 0)
 250                 goto err;
 251
 252         return 0;
 253
 254 err:
 255         free_netdev(dev_ifb);
 256         return err;
 257 }
 258
 259 static int __init ifb_init_module(void)
 260 {
 261         int i, err;
 262
 263         rtnl_lock();
 264         err = __rtnl_link_register(&ifb_link_ops);
 265
 266         for (i = 0; i < numifbs && !err; i++)
 267                 err = ifb_init_one(i);
 268         if (err)
 269                 __rtnl_link_unregister(&ifb_link_ops);
 270         rtnl_unlock();
 271
 272         return err;
 273 }
 274
 275 static void __exit ifb_cleanup_module(void)
 276 {
 277         rtnl_link_unregister(&ifb_link_ops);
 278 }
 279
 280 module_init(ifb_init_module);
 281 module_exit(ifb_cleanup_module);
 282 MODULE_LICENSE("GPL");
 283 MODULE_AUTHOR("Jamal Hadi Salim");
 284 MODULE_ALIAS_RTNL_LINK("ifb");