linux/drivers/net/ifb.c
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   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
  41struct 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
  56static int numifbs = 2;
  57
  58static void ri_tasklet(unsigned long dev);
  59static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  60static int ifb_open(struct net_device *dev);
  61static int ifb_close(struct net_device *dev);
  62
  63static 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 {
 125resched:
 126                dp->tasklet_pending = 1;
 127                tasklet_schedule(&dp->ifb_tasklet);
 128        }
 129
 130}
 131
 132static 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
 159static 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
 171static 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
 190static 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
 219static 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
 230static 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
 242static 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
 253static 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. */
 261module_param(numifbs, int, 0);
 262MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 263
 264static 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
 282err:
 283        free_netdev(dev_ifb);
 284        return err;
 285}
 286
 287static int __init ifb_init_module(void)
 288{
 289        int i, err;
 290
 291        rtnl_lock();
 292        err = __rtnl_link_register(&ifb_link_ops);
 293
 294        for (i = 0; i < numifbs && !err; i++)
 295                err = ifb_init_one(i);
 296        if (err)
 297                __rtnl_link_unregister(&ifb_link_ops);
 298        rtnl_unlock();
 299
 300        return err;
 301}
 302
 303static void __exit ifb_cleanup_module(void)
 304{
 305        rtnl_link_unregister(&ifb_link_ops);
 306}
 307
 308module_init(ifb_init_module);
 309module_exit(ifb_cleanup_module);
 310MODULE_LICENSE("GPL");
 311MODULE_AUTHOR("Jamal Hadi Salim");
 312MODULE_ALIAS_RTNL_LINK("ifb");
 313
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