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/interrupt.h>
  36 #include <linux/moduleparam.h>
  37 #include <net/pkt_sched.h>
  38 #include <net/net_namespace.h>
  39
  40 #define TX_Q_LIMIT    32
  41 struct ifb_private {
  42         struct tasklet_struct   ifb_tasklet;
  43         int     tasklet_pending;
  44
  45         struct u64_stats_sync   rsync;
  46         struct sk_buff_head     rq;
  47         u64 rx_packets;
  48         u64 rx_bytes;
  49
  50         struct u64_stats_sync   tsync;
  51         struct sk_buff_head     tq;
  52         u64 tx_packets;
  53         u64 tx_bytes;
  54 };
  55
  56 static int numifbs = 2;
  57
  58 static void ri_tasklet(unsigned long dev);
  59 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  60 static int ifb_open(struct net_device *dev);
  61 static int ifb_close(struct net_device *dev);
  62
  63 static void ri_tasklet(unsigned long dev)
  64 {
  65         struct net_device *_dev = (struct net_device *)dev;
  66         struct ifb_private *dp = netdev_priv(_dev);
  67         struct netdev_queue *txq;
  68         struct sk_buff *skb;
  69
  70         txq = netdev_get_tx_queue(_dev, 0);
  71         if ((skb = skb_peek(&dp->tq)) == NULL) {
  72                 if (__netif_tx_trylock(txq)) {
  73                         skb_queue_splice_tail_init(&dp->rq, &dp->tq);
  74                         __netif_tx_unlock(txq);
  75                 } else {
  76                         /* reschedule */
  77                         goto resched;
  78                 }
  79         }
  80
  81         while ((skb = __skb_dequeue(&dp->tq)) != NULL) {
  82                 u32 from = G_TC_FROM(skb->tc_verd);
  83
  84                 skb->tc_verd = 0;
  85                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  86
  87                 u64_stats_update_begin(&dp->tsync);
  88                 dp->tx_packets++;
  89                 dp->tx_bytes += skb->len;
  90                 u64_stats_update_end(&dp->tsync);
  91
  92                 rcu_read_lock();
  93                 skb->dev = dev_get_by_index_rcu(&init_net, skb->skb_iif);
  94                 if (!skb->dev) {
  95                         rcu_read_unlock();
  96                         dev_kfree_skb(skb);
  97                         _dev->stats.tx_dropped++;
  98                         if (skb_queue_len(&dp->tq) != 0)
  99                                 goto resched;
 100                         break;
 101                 }
 102                 rcu_read_unlock();
 103                 skb->skb_iif = _dev->ifindex;
 104
 105                 if (from & AT_EGRESS) {
 106                         dev_queue_xmit(skb);
 107                 } else if (from & AT_INGRESS) {
 108                         skb_pull(skb, skb->dev->hard_header_len);
 109                         netif_receive_skb(skb);
 110                 } else
 111                         BUG();
 112         }
 113
 114         if (__netif_tx_trylock(txq)) {
 115                 if ((skb = skb_peek(&dp->rq)) == NULL) {
 116                         dp->tasklet_pending = 0;
 117                         if (netif_queue_stopped(_dev))
 118                                 netif_wake_queue(_dev);
 119                 } else {
 120                         __netif_tx_unlock(txq);
 121                         goto resched;
 122                 }
 123                 __netif_tx_unlock(txq);
 124         } else {
 125 resched:
 126                 dp->tasklet_pending = 1;
 127                 tasklet_schedule(&dp->ifb_tasklet);
 128         }
 129
 130 }
 131
 132 static struct rtnl_link_stats64 *ifb_stats64(struct net_device *dev,
 133                                              struct rtnl_link_stats64 *stats)
 134 {
 135         struct ifb_private *dp = netdev_priv(dev);
 136         unsigned int start;
 137
 138         do {
 139                 start = u64_stats_fetch_begin_bh(&dp->rsync);
 140                 stats->rx_packets = dp->rx_packets;
 141                 stats->rx_bytes = dp->rx_bytes;
 142         } while (u64_stats_fetch_retry_bh(&dp->rsync, start));
 143
 144         do {
 145                 start = u64_stats_fetch_begin_bh(&dp->tsync);
 146
 147                 stats->tx_packets = dp->tx_packets;
 148                 stats->tx_bytes = dp->tx_bytes;
 149
 150         } while (u64_stats_fetch_retry_bh(&dp->tsync, start));
 151
 152         stats->rx_dropped = dev->stats.rx_dropped;
 153         stats->tx_dropped = dev->stats.tx_dropped;
 154
 155         return stats;
 156 }
 157
 158
 159 static const struct net_device_ops ifb_netdev_ops = {
 160         .ndo_open       = ifb_open,
 161         .ndo_stop       = ifb_close,
 162         .ndo_get_stats64 = ifb_stats64,
 163         .ndo_start_xmit = ifb_xmit,
 164         .ndo_validate_addr = eth_validate_addr,
 165 };
 166
 167 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST  | \
 168                       NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6      | \
 169                       NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_TX)
 170
 171 static void ifb_setup(struct net_device *dev)
 172 {
 173         /* Initialize the device structure. */
 174         dev->destructor = free_netdev;
 175         dev->netdev_ops = &ifb_netdev_ops;
 176
 177         /* Fill in device structure with ethernet-generic values. */
 178         ether_setup(dev);
 179         dev->tx_queue_len = TX_Q_LIMIT;
 180
 181         dev->features |= IFB_FEATURES;
 182         dev->vlan_features |= IFB_FEATURES;
 183
 184         dev->flags |= IFF_NOARP;
 185         dev->flags &= ~IFF_MULTICAST;
 186         dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
 187         eth_hw_addr_random(dev);
 188 }
 189
 190 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 191 {
 192         struct ifb_private *dp = netdev_priv(dev);
 193         u32 from = G_TC_FROM(skb->tc_verd);
 194
 195         u64_stats_update_begin(&dp->rsync);
 196         dp->rx_packets++;
 197         dp->rx_bytes += skb->len;
 198         u64_stats_update_end(&dp->rsync);
 199
 200         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 201                 dev_kfree_skb(skb);
 202                 dev->stats.rx_dropped++;
 203                 return NETDEV_TX_OK;
 204         }
 205
 206         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 207                 netif_stop_queue(dev);
 208         }
 209
 210         __skb_queue_tail(&dp->rq, skb);
 211         if (!dp->tasklet_pending) {
 212                 dp->tasklet_pending = 1;
 213                 tasklet_schedule(&dp->ifb_tasklet);
 214         }
 215
 216         return NETDEV_TX_OK;
 217 }
 218
 219 static int ifb_close(struct net_device *dev)
 220 {
 221         struct ifb_private *dp = netdev_priv(dev);
 222
 223         tasklet_kill(&dp->ifb_tasklet);
 224         netif_stop_queue(dev);
 225         __skb_queue_purge(&dp->rq);
 226         __skb_queue_purge(&dp->tq);
 227         return 0;
 228 }
 229
 230 static int ifb_open(struct net_device *dev)
 231 {
 232         struct ifb_private *dp = netdev_priv(dev);
 233
 234         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 235         __skb_queue_head_init(&dp->rq);
 236         __skb_queue_head_init(&dp->tq);
 237         netif_start_queue(dev);
 238
 239         return 0;
 240 }
 241
 242 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 243 {
 244         if (tb[IFLA_ADDRESS]) {
 245                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 246                         return -EINVAL;
 247                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 248                         return -EADDRNOTAVAIL;
 249         }
 250         return 0;
 251 }
 252
 253 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 254         .kind           = "ifb",
 255         .priv_size      = sizeof(struct ifb_private),
 256         .setup          = ifb_setup,
 257         .validate       = ifb_validate,
 258 };
 259
 260 /* Number of ifb devices to be set up by this module. */
 261 module_param(numifbs, int, 0);
 262 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 263
 264 static int __init ifb_init_one(int index)
 265 {
 266         struct net_device *dev_ifb;
 267         int err;
 268
 269         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 270                                  "ifb%d", ifb_setup);
 271
 272         if (!dev_ifb)
 273                 return -ENOMEM;
 274
 275         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 276         err = register_netdevice(dev_ifb);
 277         if (err < 0)
 278                 goto err;
 279
 280         return 0;
 281
 282 err:
 283         free_netdev(dev_ifb);
 284         return err;
 285 }
 286
 287 static int __init ifb_init_module(void)
 288 {
 289         int i, err;
 290
 291         rtnl_lock();
 292         err = __rtnl_link_register(&ifb_link_ops);
 293         if (err < 0)
 294                 goto out;
 295
 296         for (i = 0; i < numifbs && !err; i++) {
 297                 err = ifb_init_one(i);
 298                 cond_resched();
 299         }
 300         if (err)
 301                 __rtnl_link_unregister(&ifb_link_ops);
 302
 303 out:
 304         rtnl_unlock();
 305
 306         return err;
 307 }
 308
 309 static void __exit ifb_cleanup_module(void)
 310 {
 311         rtnl_link_unregister(&ifb_link_ops);
 312 }
 313
 314 module_init(ifb_init_module);
 315 module_exit(ifb_cleanup_module);
 316 MODULE_LICENSE("GPL");
 317 MODULE_AUTHOR("Jamal Hadi Salim");
 318 MODULE_ALIAS_RTNL_LINK("ifb");