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_TX_SKB_SHARING;
 189         netif_keep_dst(dev);
 190         eth_hw_addr_random(dev);
 191 }
 192
 193 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 194 {
 195         struct ifb_private *dp = netdev_priv(dev);
 196         u32 from = G_TC_FROM(skb->tc_verd);
 197
 198         u64_stats_update_begin(&dp->rsync);
 199         dp->rx_packets++;
 200         dp->rx_bytes += skb->len;
 201         u64_stats_update_end(&dp->rsync);
 202
 203         if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) {
 204                 dev_kfree_skb(skb);
 205                 dev->stats.rx_dropped++;
 206                 return NETDEV_TX_OK;
 207         }
 208
 209         if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
 210                 netif_stop_queue(dev);
 211         }
 212
 213         __skb_queue_tail(&dp->rq, skb);
 214         if (!dp->tasklet_pending) {
 215                 dp->tasklet_pending = 1;
 216                 tasklet_schedule(&dp->ifb_tasklet);
 217         }
 218
 219         return NETDEV_TX_OK;
 220 }
 221
 222 static int ifb_close(struct net_device *dev)
 223 {
 224         struct ifb_private *dp = netdev_priv(dev);
 225
 226         tasklet_kill(&dp->ifb_tasklet);
 227         netif_stop_queue(dev);
 228         __skb_queue_purge(&dp->rq);
 229         __skb_queue_purge(&dp->tq);
 230         return 0;
 231 }
 232
 233 static int ifb_open(struct net_device *dev)
 234 {
 235         struct ifb_private *dp = netdev_priv(dev);
 236
 237         tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
 238         __skb_queue_head_init(&dp->rq);
 239         __skb_queue_head_init(&dp->tq);
 240         netif_start_queue(dev);
 241
 242         return 0;
 243 }
 244
 245 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[])
 246 {
 247         if (tb[IFLA_ADDRESS]) {
 248                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 249                         return -EINVAL;
 250                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 251                         return -EADDRNOTAVAIL;
 252         }
 253         return 0;
 254 }
 255
 256 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 257         .kind           = "ifb",
 258         .priv_size      = sizeof(struct ifb_private),
 259         .setup          = ifb_setup,
 260         .validate       = ifb_validate,
 261 };
 262
 263 /* Number of ifb devices to be set up by this module. */
 264 module_param(numifbs, int, 0);
 265 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 266
 267 static int __init ifb_init_one(int index)
 268 {
 269         struct net_device *dev_ifb;
 270         struct ifb_private *dp;
 271         int err;
 272
 273         dev_ifb = alloc_netdev(sizeof(struct ifb_private), "ifb%d",
 274                                NET_NAME_UNKNOWN, ifb_setup);
 275
 276         if (!dev_ifb)
 277                 return -ENOMEM;
 278
 279         dp = netdev_priv(dev_ifb);
 280         u64_stats_init(&dp->rsync);
 281         u64_stats_init(&dp->tsync);
 282
 283         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 284         err = register_netdevice(dev_ifb);
 285         if (err < 0)
 286                 goto err;
 287
 288         return 0;
 289
 290 err:
 291         free_netdev(dev_ifb);
 292         return err;
 293 }
 294
 295 static int __init ifb_init_module(void)
 296 {
 297         int i, err;
 298
 299         rtnl_lock();
 300         err = __rtnl_link_register(&ifb_link_ops);
 301         if (err < 0)
 302                 goto out;
 303
 304         for (i = 0; i < numifbs && !err; i++) {
 305                 err = ifb_init_one(i);
 306                 cond_resched();
 307         }
 308         if (err)
 309                 __rtnl_link_unregister(&ifb_link_ops);
 310
 311 out:
 312         rtnl_unlock();
 313
 314         return err;
 315 }
 316
 317 static void __exit ifb_cleanup_module(void)
 318 {
 319         rtnl_link_unregister(&ifb_link_ops);
 320 }
 321
 322 module_init(ifb_init_module);
 323 module_exit(ifb_cleanup_module);
 324 MODULE_LICENSE("GPL");
 325 MODULE_AUTHOR("Jamal Hadi Salim");
 326 MODULE_ALIAS_RTNL_LINK("ifb");