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(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 {
 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_CTAG_TX         | \
 170                      NETIF_F_HW_VLAN_STAG_TX)
 171
 172static 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
 191static 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
 220static 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
 231static 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
 243static 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
 254static 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. */
 262module_param(numifbs, int, 0);
 263MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 264
 265static 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
 283err:
 284        free_netdev(dev_ifb);
 285        return err;
 286}
 287
 288static int __init ifb_init_module(void)
 289{
 290        int i, err;
 291
 292        rtnl_lock();
 293        err = __rtnl_link_register(&ifb_link_ops);
 294
 295        for (i = 0; i < numifbs && !err; i++)
 296                err = ifb_init_one(i);
 297        if (err)
 298                __rtnl_link_unregister(&ifb_link_ops);
 299        rtnl_unlock();
 300
 301        return err;
 302}
 303
 304static void __exit ifb_cleanup_module(void)
 305{
 306        rtnl_link_unregister(&ifb_link_ops);
 307}
 308
 309module_init(ifb_init_module);
 310module_exit(ifb_cleanup_module);
 311MODULE_LICENSE("GPL");
 312MODULE_AUTHOR("Jamal Hadi Salim");
 313MODULE_ALIAS_RTNL_LINK("ifb");
 314
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