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