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(dev_net(_dev), 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_irq(&dp->rsync);
 140                 stats->rx_packets = dp->rx_packets;
 141                 stats->rx_bytes = dp->rx_bytes;
 142         } while (u64_stats_fetch_retry_irq(&dp->rsync, start));
 143
 144         do {
 145                 start = u64_stats_fetch_begin_irq(&dp->tsync);
 146
 147                 stats->tx_packets = dp->tx_packets;
 148                 stats->tx_bytes = dp->tx_bytes;
 149
 150         } while (u64_stats_fetch_retry_irq(&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_CTAG_TX         | \
 170                       NETIF_F_HW_VLAN_STAG_TX)
 171
 172 static void ifb_setup(struct net_device *dev)
 173 {
 174         /* Initialize the device structure. */
 175         dev->destructor = free_netdev;
 176         dev->netdev_ops = &ifb_netdev_ops;
 177
 178         /* Fill in device structure with ethernet-generic values. */
 179         ether_setup(dev);
 180         dev->tx_queue_len = TX_Q_LIMIT;
 181
 182         dev->features |= IFB_FEATURES;
 183         dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
 184                                                NETIF_F_HW_VLAN_STAG_TX);
 185
 186         dev->flags |= IFF_NOARP;
 187         dev->flags &= ~IFF_MULTICAST;
 188         dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
 189         eth_hw_addr_random(dev);
 190 }
 191
 192 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 193 {
 194         struct ifb_private *dp = netdev_priv(dev);
 195         u32 from = G_TC_FROM(skb->tc_verd);
 196
 197         u64_stats_update_begin(&dp->rsync);
 198         dp->rx_packets++;
 199         dp->rx_bytes += skb->len;
 200         u64_stats_update_end(&dp->rsync);
 201
 202         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 203                 dev_kfree_skb(skb);
 204                 dev->stats.rx_dropped++;
 205                 return NETDEV_TX_OK;
 206         }
 207
 208         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 209                 netif_stop_queue(dev);
 210         }
 211
 212         __skb_queue_tail(&dp->rq, skb);
 213         if (!dp->tasklet_pending) {
 214                 dp->tasklet_pending = 1;
 215                 tasklet_schedule(&dp->ifb_tasklet);
 216         }
 217
 218         return NETDEV_TX_OK;
 219 }
 220
 221 static int ifb_close(struct net_device *dev)
 222 {
 223         struct ifb_private *dp = netdev_priv(dev);
 224
 225         tasklet_kill(&dp->ifb_tasklet);
 226         netif_stop_queue(dev);
 227         __skb_queue_purge(&dp->rq);
 228         __skb_queue_purge(&dp->tq);
 229         return 0;
 230 }
 231
 232 static int ifb_open(struct net_device *dev)
 233 {
 234         struct ifb_private *dp = netdev_priv(dev);
 235
 236         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 237         __skb_queue_head_init(&dp->rq);
 238         __skb_queue_head_init(&dp->tq);
 239         netif_start_queue(dev);
 240
 241         return 0;
 242 }
 243
 244 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 245 {
 246         if (tb[IFLA_ADDRESS]) {
 247                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 248                         return -EINVAL;
 249                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 250                         return -EADDRNOTAVAIL;
 251         }
 252         return 0;
 253 }
 254
 255 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 256         .kind           = "ifb",
 257         .priv_size      = sizeof(struct ifb_private),
 258         .setup          = ifb_setup,
 259         .validate       = ifb_validate,
 260 };
 261
 262 /* Number of ifb devices to be set up by this module. */
 263 module_param(numifbs, int, 0);
 264 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 265
 266 static int __init ifb_init_one(int index)
 267 {
 268         struct net_device *dev_ifb;
 269         struct ifb_private *dp;
 270         int err;
 271
 272         dev_ifb = alloc_netdev(sizeof(struct ifb_private),
 273                                  "ifb%d", ifb_setup);
 274
 275         if (!dev_ifb)
 276                 return -ENOMEM;
 277
 278         dp = netdev_priv(dev_ifb);
 279         u64_stats_init(&dp->rsync);
 280         u64_stats_init(&dp->tsync);
 281
 282         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 283         err = register_netdevice(dev_ifb);
 284         if (err < 0)
 285                 goto err;
 286
 287         return 0;
 288
 289 err:
 290         free_netdev(dev_ifb);
 291         return err;
 292 }
 293
 294 static int __init ifb_init_module(void)
 295 {
 296         int i, err;
 297
 298         rtnl_lock();
 299         err = __rtnl_link_register(&ifb_link_ops);
 300         if (err < 0)
 301                 goto out;
 302
 303         for (i = 0; i < numifbs && !err; i++) {
 304                 err = ifb_init_one(i);
 305                 cond_resched();
 306         }
 307         if (err)
 308                 __rtnl_link_unregister(&ifb_link_ops);
 309
 310 out:
 311         rtnl_unlock();
 312
 313         return err;
 314 }
 315
 316 static void __exit ifb_cleanup_module(void)
 317 {
 318         rtnl_link_unregister(&ifb_link_ops);
 319 }
 320
 321 module_init(ifb_init_module);
 322 module_exit(ifb_cleanup_module);
 323 MODULE_LICENSE("GPL");
 324 MODULE_AUTHOR("Jamal Hadi Salim");
 325 MODULE_ALIAS_RTNL_LINK("ifb");