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_q_private {
  42         struct net_device       *dev;
  43         struct tasklet_struct   ifb_tasklet;
  44         int                     tasklet_pending;
  45         int                     txqnum;
  46         struct sk_buff_head     rq;
  47         u64                     rx_packets;
  48         u64                     rx_bytes;
  49         struct u64_stats_sync   rsync;
  50
  51         struct u64_stats_sync   tsync;
  52         u64                     tx_packets;
  53         u64                     tx_bytes;
  54         struct sk_buff_head     tq;
  55 } ____cacheline_aligned_in_smp;
  56
  57 struct ifb_dev_private {
  58         struct ifb_q_private *tx_private;
  59 };
  60
  61 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  62 static int ifb_open(struct net_device *dev);
  63 static int ifb_close(struct net_device *dev);
  64
  65 static void ifb_ri_tasklet(unsigned long _txp)
  66 {
  67         struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
  68         struct netdev_queue *txq;
  69         struct sk_buff *skb;
  70
  71         txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
  72         skb = skb_peek(&txp->tq);
  73         if (!skb) {
  74                 if (!__netif_tx_trylock(txq))
  75                         goto resched;
  76                 skb_queue_splice_tail_init(&txp->rq, &txp->tq);
  77                 __netif_tx_unlock(txq);
  78         }
  79
  80         while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
  81                 u32 from = G_TC_FROM(skb->tc_verd);
  82
  83                 skb->tc_verd = 0;
  84                 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
  85
  86                 u64_stats_update_begin(&txp->tsync);
  87                 txp->tx_packets++;
  88                 txp->tx_bytes += skb->len;
  89                 u64_stats_update_end(&txp->tsync);
  90
  91                 rcu_read_lock();
  92                 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
  93                 if (!skb->dev) {
  94                         rcu_read_unlock();
  95                         dev_kfree_skb(skb);
  96                         txp->dev->stats.tx_dropped++;
  97                         if (skb_queue_len(&txp->tq) != 0)
  98                                 goto resched;
  99                         break;
 100                 }
 101                 rcu_read_unlock();
 102                 skb->skb_iif = txp->dev->ifindex;
 103
 104                 if (from & AT_EGRESS) {
 105                         dev_queue_xmit(skb);
 106                 } else if (from & AT_INGRESS) {
 107                         skb_pull(skb, skb->mac_len);
 108                         netif_receive_skb(skb);
 109                 } else
 110                         BUG();
 111         }
 112
 113         if (__netif_tx_trylock(txq)) {
 114                 skb = skb_peek(&txp->rq);
 115                 if (!skb) {
 116                         txp->tasklet_pending = 0;
 117                         if (netif_tx_queue_stopped(txq))
 118                                 netif_tx_wake_queue(txq);
 119                 } else {
 120                         __netif_tx_unlock(txq);
 121                         goto resched;
 122                 }
 123                 __netif_tx_unlock(txq);
 124         } else {
 125 resched:
 126                 txp->tasklet_pending = 1;
 127                 tasklet_schedule(&txp->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_dev_private *dp = netdev_priv(dev);
 136         struct ifb_q_private *txp = dp->tx_private;
 137         unsigned int start;
 138         u64 packets, bytes;
 139         int i;
 140
 141         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 142                 do {
 143                         start = u64_stats_fetch_begin_irq(&txp->rsync);
 144                         packets = txp->rx_packets;
 145                         bytes = txp->rx_bytes;
 146                 } while (u64_stats_fetch_retry_irq(&txp->rsync, start));
 147                 stats->rx_packets += packets;
 148                 stats->rx_bytes += bytes;
 149
 150                 do {
 151                         start = u64_stats_fetch_begin_irq(&txp->tsync);
 152                         packets = txp->tx_packets;
 153                         bytes = txp->tx_bytes;
 154                 } while (u64_stats_fetch_retry_irq(&txp->tsync, start));
 155                 stats->tx_packets += packets;
 156                 stats->tx_bytes += bytes;
 157         }
 158         stats->rx_dropped = dev->stats.rx_dropped;
 159         stats->tx_dropped = dev->stats.tx_dropped;
 160
 161         return stats;
 162 }
 163
 164 static int ifb_dev_init(struct net_device *dev)
 165 {
 166         struct ifb_dev_private *dp = netdev_priv(dev);
 167         struct ifb_q_private *txp;
 168         int i;
 169
 170         txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
 171         if (!txp)
 172                 return -ENOMEM;
 173         dp->tx_private = txp;
 174         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 175                 txp->txqnum = i;
 176                 txp->dev = dev;
 177                 __skb_queue_head_init(&txp->rq);
 178                 __skb_queue_head_init(&txp->tq);
 179                 u64_stats_init(&txp->rsync);
 180                 u64_stats_init(&txp->tsync);
 181                 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
 182                              (unsigned long)txp);
 183                 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
 184         }
 185         return 0;
 186 }
 187
 188 static const struct net_device_ops ifb_netdev_ops = {
 189         .ndo_open       = ifb_open,
 190         .ndo_stop       = ifb_close,
 191         .ndo_get_stats64 = ifb_stats64,
 192         .ndo_start_xmit = ifb_xmit,
 193         .ndo_validate_addr = eth_validate_addr,
 194         .ndo_init       = ifb_dev_init,
 195 };
 196
 197 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST  | \
 198                       NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6      | \
 199                       NETIF_F_GSO_ENCAP_ALL                             | \
 200                       NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX         | \
 201                       NETIF_F_HW_VLAN_STAG_TX)
 202
 203 static void ifb_dev_free(struct net_device *dev)
 204 {
 205         struct ifb_dev_private *dp = netdev_priv(dev);
 206         struct ifb_q_private *txp = dp->tx_private;
 207         int i;
 208
 209         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 210                 tasklet_kill(&txp->ifb_tasklet);
 211                 __skb_queue_purge(&txp->rq);
 212                 __skb_queue_purge(&txp->tq);
 213         }
 214         kfree(dp->tx_private);
 215         free_netdev(dev);
 216 }
 217
 218 static void ifb_setup(struct net_device *dev)
 219 {
 220         /* Initialize the device structure. */
 221         dev->netdev_ops = &ifb_netdev_ops;
 222
 223         /* Fill in device structure with ethernet-generic values. */
 224         ether_setup(dev);
 225         dev->tx_queue_len = TX_Q_LIMIT;
 226
 227         dev->features |= IFB_FEATURES;
 228         dev->hw_features |= dev->features;
 229         dev->hw_enc_features |= dev->features;
 230         dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
 231                                                NETIF_F_HW_VLAN_STAG_TX);
 232
 233         dev->flags |= IFF_NOARP;
 234         dev->flags &= ~IFF_MULTICAST;
 235         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 236         netif_keep_dst(dev);
 237         eth_hw_addr_random(dev);
 238         dev->destructor = ifb_dev_free;
 239 }
 240
 241 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 242 {
 243         struct ifb_dev_private *dp = netdev_priv(dev);
 244         u32 from = G_TC_FROM(skb->tc_verd);
 245         struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
 246
 247         u64_stats_update_begin(&txp->rsync);
 248         txp->rx_packets++;
 249         txp->rx_bytes += skb->len;
 250         u64_stats_update_end(&txp->rsync);
 251
 252         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 253                 dev_kfree_skb(skb);
 254                 dev->stats.rx_dropped++;
 255                 return NETDEV_TX_OK;
 256         }
 257
 258         if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
 259                 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
 260
 261         __skb_queue_tail(&txp->rq, skb);
 262         if (!txp->tasklet_pending) {
 263                 txp->tasklet_pending = 1;
 264                 tasklet_schedule(&txp->ifb_tasklet);
 265         }
 266
 267         return NETDEV_TX_OK;
 268 }
 269
 270 static int ifb_close(struct net_device *dev)
 271 {
 272         netif_tx_stop_all_queues(dev);
 273         return 0;
 274 }
 275
 276 static int ifb_open(struct net_device *dev)
 277 {
 278         netif_tx_start_all_queues(dev);
 279         return 0;
 280 }
 281
 282 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 283 {
 284         if (tb[IFLA_ADDRESS]) {
 285                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 286                         return -EINVAL;
 287                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 288                         return -EADDRNOTAVAIL;
 289         }
 290         return 0;
 291 }
 292
 293 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 294         .kind           = "ifb",
 295         .priv_size      = sizeof(struct ifb_dev_private),
 296         .setup          = ifb_setup,
 297         .validate       = ifb_validate,
 298 };
 299
 300 /* Number of ifb devices to be set up by this module.
 301  * Note that these legacy devices have one queue.
 302  * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
 303  */
 304 static int numifbs = 2;
 305 module_param(numifbs, int, 0);
 306 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 307
 308 static int __init ifb_init_one(int index)
 309 {
 310         struct net_device *dev_ifb;
 311         int err;
 312
 313         dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
 314                                NET_NAME_UNKNOWN, ifb_setup);
 315
 316         if (!dev_ifb)
 317                 return -ENOMEM;
 318
 319         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 320         err = register_netdevice(dev_ifb);
 321         if (err < 0)
 322                 goto err;
 323
 324         return 0;
 325
 326 err:
 327         free_netdev(dev_ifb);
 328         return err;
 329 }
 330
 331 static int __init ifb_init_module(void)
 332 {
 333         int i, err;
 334
 335         rtnl_lock();
 336         err = __rtnl_link_register(&ifb_link_ops);
 337         if (err < 0)
 338                 goto out;
 339
 340         for (i = 0; i < numifbs && !err; i++) {
 341                 err = ifb_init_one(i);
 342                 cond_resched();
 343         }
 344         if (err)
 345                 __rtnl_link_unregister(&ifb_link_ops);
 346
 347 out:
 348         rtnl_unlock();
 349
 350         return err;
 351 }
 352
 353 static void __exit ifb_cleanup_module(void)
 354 {
 355         rtnl_link_unregister(&ifb_link_ops);
 356 }
 357
 358 module_init(ifb_init_module);
 359 module_exit(ifb_cleanup_module);
 360 MODULE_LICENSE("GPL");
 361 MODULE_AUTHOR("Jamal Hadi Salim");
 362 MODULE_ALIAS_RTNL_LINK("ifb");