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
  38 #define TX_TIMEOUT  (2*HZ)
  39
  40 #define TX_Q_LIMIT    32
  41 struct ifb_private {
  42         struct net_device_stats stats;
  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 struct net_device_stats *ifb_get_stats(struct net_device *dev);
  64 static int ifb_open(struct net_device *dev);
  65 static int ifb_close(struct net_device *dev);
  66
  67 static void ri_tasklet(unsigned long dev)
  68 {
  69
  70         struct net_device *_dev = (struct net_device *)dev;
  71         struct ifb_private *dp = netdev_priv(_dev);
  72         struct net_device_stats *stats = &dp->stats;
  73         struct sk_buff *skb;
  74
  75         dp->st_task_enter++;
  76         if ((skb = skb_peek(&dp->tq)) == NULL) {
  77                 dp->st_txq_refl_try++;
  78                 if (netif_tx_trylock(_dev)) {
  79                         dp->st_rxq_enter++;
  80                         while ((skb = skb_dequeue(&dp->rq)) != NULL) {
  81                                 skb_queue_tail(&dp->tq, skb);
  82                                 dp->st_rx2tx_tran++;
  83                         }
  84                         netif_tx_unlock(_dev);
  85                 } else {
  86                         /* reschedule */
  87                         dp->st_rxq_notenter++;
  88                         goto resched;
  89                 }
  90         }
  91
  92         while ((skb = skb_dequeue(&dp->tq)) != NULL) {
  93                 u32 from = G_TC_FROM(skb->tc_verd);
  94
  95                 skb->tc_verd = 0;
  96                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  97                 stats->tx_packets++;
  98                 stats->tx_bytes +=skb->len;
  99
 100                 skb->dev = __dev_get_by_index(skb->iif);
 101                 if (!skb->dev) {
 102                         dev_kfree_skb(skb);
 103                         stats->tx_dropped++;
 104                         break;
 105                 }
 106                 skb->iif = _dev->ifindex;
 107
 108                 if (from & AT_EGRESS) {
 109                         dp->st_rx_frm_egr++;
 110                         dev_queue_xmit(skb);
 111                 } else if (from & AT_INGRESS) {
 112                         dp->st_rx_frm_ing++;
 113                         skb_pull(skb, skb->dev->hard_header_len);
 114                         netif_rx(skb);
 115                 } else
 116                         BUG();
 117         }
 118
 119         if (netif_tx_trylock(_dev)) {
 120                 dp->st_rxq_check++;
 121                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 122                         dp->tasklet_pending = 0;
 123                         if (netif_queue_stopped(_dev))
 124                                 netif_wake_queue(_dev);
 125                 } else {
 126                         dp->st_rxq_rsch++;
 127                         netif_tx_unlock(_dev);
 128                         goto resched;
 129                 }
 130                 netif_tx_unlock(_dev);
 131         } else {
 132 resched:
 133                 dp->tasklet_pending = 1;
 134                 tasklet_schedule(&dp->ifb_tasklet);
 135         }
 136
 137 }
 138
 139 static void ifb_setup(struct net_device *dev)
 140 {
 141         /* Initialize the device structure. */
 142         dev->get_stats = ifb_get_stats;
 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         SET_MODULE_OWNER(dev);
 155         random_ether_addr(dev->dev_addr);
 156 }
 157
 158 static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 159 {
 160         struct ifb_private *dp = netdev_priv(dev);
 161         struct net_device_stats *stats = &dp->stats;
 162         int ret = 0;
 163         u32 from = G_TC_FROM(skb->tc_verd);
 164
 165         stats->rx_packets++;
 166         stats->rx_bytes+=skb->len;
 167
 168         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
 169                 dev_kfree_skb(skb);
 170                 stats->rx_dropped++;
 171                 return ret;
 172         }
 173
 174         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 175                 netif_stop_queue(dev);
 176         }
 177
 178         dev->trans_start = jiffies;
 179         skb_queue_tail(&dp->rq, skb);
 180         if (!dp->tasklet_pending) {
 181                 dp->tasklet_pending = 1;
 182                 tasklet_schedule(&dp->ifb_tasklet);
 183         }
 184
 185         return ret;
 186 }
 187
 188 static struct net_device_stats *ifb_get_stats(struct net_device *dev)
 189 {
 190         struct ifb_private *dp = netdev_priv(dev);
 191         struct net_device_stats *stats = &dp->stats;
 192
 193         pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n",
 194                 dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter,
 195                 dp->st_rx2tx_tran, dp->st_rxq_notenter, dp->st_rx_frm_egr,
 196                 dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch);
 197
 198         return stats;
 199 }
 200
 201 static int ifb_close(struct net_device *dev)
 202 {
 203         struct ifb_private *dp = netdev_priv(dev);
 204
 205         tasklet_kill(&dp->ifb_tasklet);
 206         netif_stop_queue(dev);
 207         skb_queue_purge(&dp->rq);
 208         skb_queue_purge(&dp->tq);
 209         return 0;
 210 }
 211
 212 static int ifb_open(struct net_device *dev)
 213 {
 214         struct ifb_private *dp = netdev_priv(dev);
 215
 216         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 217         skb_queue_head_init(&dp->rq);
 218         skb_queue_head_init(&dp->tq);
 219         netif_start_queue(dev);
 220
 221         return 0;
 222 }
 223
 224 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 225         .kind           = "ifb",
 226         .priv_size      = sizeof(struct ifb_private),
 227         .setup          = ifb_setup,
 228 };
 229
 230 /* Number of ifb devices to be set up by this module. */
 231 module_param(numifbs, int, 0);
 232 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 233
 234 static int __init ifb_init_one(int index)
 235 {
 236         struct net_device *dev_ifb;
 237         int err;
 238
 239         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 240                                  "ifb%d", ifb_setup);
 241
 242         if (!dev_ifb)
 243                 return -ENOMEM;
 244
 245         err = dev_alloc_name(dev_ifb, dev_ifb->name);
 246         if (err < 0)
 247                 goto err;
 248
 249         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 250         err = register_netdevice(dev_ifb);
 251         if (err < 0)
 252                 goto err;
 253         return 0;
 254
 255 err:
 256         free_netdev(dev_ifb);
 257         return err;
 258 }
 259
 260 static int __init ifb_init_module(void)
 261 {
 262         int i, err;
 263
 264         rtnl_lock();
 265         err = __rtnl_link_register(&ifb_link_ops);
 266
 267         for (i = 0; i < numifbs && !err; i++)
 268                 err = ifb_init_one(i);
 269         if (err)
 270                 __rtnl_link_unregister(&ifb_link_ops);
 271         rtnl_unlock();
 272
 273         return err;
 274 }
 275
 276 static void __exit ifb_cleanup_module(void)
 277 {
 278         rtnl_link_unregister(&ifb_link_ops);
 279 }
 280
 281 module_init(ifb_init_module);
 282 module_exit(ifb_cleanup_module);
 283 MODULE_LICENSE("GPL");
 284 MODULE_AUTHOR("Jamal Hadi Salim");
 285 MODULE_ALIAS_RTNL_LINK("ifb");