drivers/net/ifb.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* drivers/net/ifb.c:
   3
   4         The purpose of this driver is to provide a device that allows
   5         for sharing of resources:
   6
   7         1) qdiscs/policies that are per device as opposed to system wide.
   8         ifb allows for a device which can be redirected to thus providing
   9         an impression of sharing.
  10
  11         2) Allows for queueing incoming traffic for shaping instead of
  12         dropping.
  13
  14         The original concept is based on what is known as the IMQ
  15         driver initially written by Martin Devera, later rewritten
  16         by Patrick McHardy and then maintained by Andre Correa.
  17
  18         You need the tc action  mirror or redirect to feed this device
  19         packets.
  20
  21
  22         Authors:        Jamal Hadi Salim (2005)
  23
  24 */
  25
  26
  27 #include <linux/module.h>
  28 #include <linux/kernel.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/etherdevice.h>
  31 #include <linux/init.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/moduleparam.h>
  34 #include <net/pkt_sched.h>
  35 #include <net/net_namespace.h>
  36
  37 #define TX_Q_LIMIT    32
  38 struct ifb_q_private {
  39         struct net_device       *dev;
  40         struct tasklet_struct   ifb_tasklet;
  41         int                     tasklet_pending;
  42         int                     txqnum;
  43         struct sk_buff_head     rq;
  44         u64                     rx_packets;
  45         u64                     rx_bytes;
  46         struct u64_stats_sync   rsync;
  47
  48         struct u64_stats_sync   tsync;
  49         u64                     tx_packets;
  50         u64                     tx_bytes;
  51         struct sk_buff_head     tq;
  52 } ____cacheline_aligned_in_smp;
  53
  54 struct ifb_dev_private {
  55         struct ifb_q_private *tx_private;
  56 };
  57
  58 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
  59 static int ifb_open(struct net_device *dev);
  60 static int ifb_close(struct net_device *dev);
  61
  62 static void ifb_ri_tasklet(unsigned long _txp)
  63 {
  64         struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
  65         struct netdev_queue *txq;
  66         struct sk_buff *skb;
  67
  68         txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
  69         skb = skb_peek(&txp->tq);
  70         if (!skb) {
  71                 if (!__netif_tx_trylock(txq))
  72                         goto resched;
  73                 skb_queue_splice_tail_init(&txp->rq, &txp->tq);
  74                 __netif_tx_unlock(txq);
  75         }
  76
  77         while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
  78                 skb->redirected = 0;
  79                 skb->tc_skip_classify = 1;
  80
  81                 u64_stats_update_begin(&txp->tsync);
  82                 txp->tx_packets++;
  83                 txp->tx_bytes += skb->len;
  84                 u64_stats_update_end(&txp->tsync);
  85
  86                 rcu_read_lock();
  87                 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
  88                 if (!skb->dev) {
  89                         rcu_read_unlock();
  90                         dev_kfree_skb(skb);
  91                         txp->dev->stats.tx_dropped++;
  92                         if (skb_queue_len(&txp->tq) != 0)
  93                                 goto resched;
  94                         break;
  95                 }
  96                 rcu_read_unlock();
  97                 skb->skb_iif = txp->dev->ifindex;
  98
  99                 if (!skb->from_ingress) {
 100                         dev_queue_xmit(skb);
 101                 } else {
 102                         skb_pull_rcsum(skb, skb->mac_len);
 103                         netif_receive_skb(skb);
 104                 }
 105         }
 106
 107         if (__netif_tx_trylock(txq)) {
 108                 skb = skb_peek(&txp->rq);
 109                 if (!skb) {
 110                         txp->tasklet_pending = 0;
 111                         if (netif_tx_queue_stopped(txq))
 112                                 netif_tx_wake_queue(txq);
 113                 } else {
 114                         __netif_tx_unlock(txq);
 115                         goto resched;
 116                 }
 117                 __netif_tx_unlock(txq);
 118         } else {
 119 resched:
 120                 txp->tasklet_pending = 1;
 121                 tasklet_schedule(&txp->ifb_tasklet);
 122         }
 123
 124 }
 125
 126 static void ifb_stats64(struct net_device *dev,
 127                         struct rtnl_link_stats64 *stats)
 128 {
 129         struct ifb_dev_private *dp = netdev_priv(dev);
 130         struct ifb_q_private *txp = dp->tx_private;
 131         unsigned int start;
 132         u64 packets, bytes;
 133         int i;
 134
 135         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 136                 do {
 137                         start = u64_stats_fetch_begin_irq(&txp->rsync);
 138                         packets = txp->rx_packets;
 139                         bytes = txp->rx_bytes;
 140                 } while (u64_stats_fetch_retry_irq(&txp->rsync, start));
 141                 stats->rx_packets += packets;
 142                 stats->rx_bytes += bytes;
 143
 144                 do {
 145                         start = u64_stats_fetch_begin_irq(&txp->tsync);
 146                         packets = txp->tx_packets;
 147                         bytes = txp->tx_bytes;
 148                 } while (u64_stats_fetch_retry_irq(&txp->tsync, start));
 149                 stats->tx_packets += packets;
 150                 stats->tx_bytes += bytes;
 151         }
 152         stats->rx_dropped = dev->stats.rx_dropped;
 153         stats->tx_dropped = dev->stats.tx_dropped;
 154 }
 155
 156 static int ifb_dev_init(struct net_device *dev)
 157 {
 158         struct ifb_dev_private *dp = netdev_priv(dev);
 159         struct ifb_q_private *txp;
 160         int i;
 161
 162         txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
 163         if (!txp)
 164                 return -ENOMEM;
 165         dp->tx_private = txp;
 166         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 167                 txp->txqnum = i;
 168                 txp->dev = dev;
 169                 __skb_queue_head_init(&txp->rq);
 170                 __skb_queue_head_init(&txp->tq);
 171                 u64_stats_init(&txp->rsync);
 172                 u64_stats_init(&txp->tsync);
 173                 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
 174                              (unsigned long)txp);
 175                 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
 176         }
 177         return 0;
 178 }
 179
 180 static const struct net_device_ops ifb_netdev_ops = {
 181         .ndo_open       = ifb_open,
 182         .ndo_stop       = ifb_close,
 183         .ndo_get_stats64 = ifb_stats64,
 184         .ndo_start_xmit = ifb_xmit,
 185         .ndo_validate_addr = eth_validate_addr,
 186         .ndo_init       = ifb_dev_init,
 187 };
 188
 189 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST  | \
 190                       NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6      | \
 191                       NETIF_F_GSO_ENCAP_ALL                             | \
 192                       NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX         | \
 193                       NETIF_F_HW_VLAN_STAG_TX)
 194
 195 static void ifb_dev_free(struct net_device *dev)
 196 {
 197         struct ifb_dev_private *dp = netdev_priv(dev);
 198         struct ifb_q_private *txp = dp->tx_private;
 199         int i;
 200
 201         for (i = 0; i < dev->num_tx_queues; i++,txp++) {
 202                 tasklet_kill(&txp->ifb_tasklet);
 203                 __skb_queue_purge(&txp->rq);
 204                 __skb_queue_purge(&txp->tq);
 205         }
 206         kfree(dp->tx_private);
 207 }
 208
 209 static void ifb_setup(struct net_device *dev)
 210 {
 211         /* Initialize the device structure. */
 212         dev->netdev_ops = &ifb_netdev_ops;
 213
 214         /* Fill in device structure with ethernet-generic values. */
 215         ether_setup(dev);
 216         dev->tx_queue_len = TX_Q_LIMIT;
 217
 218         dev->features |= IFB_FEATURES;
 219         dev->hw_features |= dev->features;
 220         dev->hw_enc_features |= dev->features;
 221         dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
 222                                                NETIF_F_HW_VLAN_STAG_TX);
 223
 224         dev->flags |= IFF_NOARP;
 225         dev->flags &= ~IFF_MULTICAST;
 226         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 227         netif_keep_dst(dev);
 228         eth_hw_addr_random(dev);
 229         dev->needs_free_netdev = true;
 230         dev->priv_destructor = ifb_dev_free;
 231
 232         dev->min_mtu = 0;
 233         dev->max_mtu = 0;
 234 }
 235
 236 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
 237 {
 238         struct ifb_dev_private *dp = netdev_priv(dev);
 239         struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
 240
 241         u64_stats_update_begin(&txp->rsync);
 242         txp->rx_packets++;
 243         txp->rx_bytes += skb->len;
 244         u64_stats_update_end(&txp->rsync);
 245
 246         if (!skb->redirected || !skb->skb_iif) {
 247                 dev_kfree_skb(skb);
 248                 dev->stats.rx_dropped++;
 249                 return NETDEV_TX_OK;
 250         }
 251
 252         if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
 253                 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
 254
 255         __skb_queue_tail(&txp->rq, skb);
 256         if (!txp->tasklet_pending) {
 257                 txp->tasklet_pending = 1;
 258                 tasklet_schedule(&txp->ifb_tasklet);
 259         }
 260
 261         return NETDEV_TX_OK;
 262 }
 263
 264 static int ifb_close(struct net_device *dev)
 265 {
 266         netif_tx_stop_all_queues(dev);
 267         return 0;
 268 }
 269
 270 static int ifb_open(struct net_device *dev)
 271 {
 272         netif_tx_start_all_queues(dev);
 273         return 0;
 274 }
 275
 276 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
 277                         struct netlink_ext_ack *extack)
 278 {
 279         if (tb[IFLA_ADDRESS]) {
 280                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 281                         return -EINVAL;
 282                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 283                         return -EADDRNOTAVAIL;
 284         }
 285         return 0;
 286 }
 287
 288 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 289         .kind           = "ifb",
 290         .priv_size      = sizeof(struct ifb_dev_private),
 291         .setup          = ifb_setup,
 292         .validate       = ifb_validate,
 293 };
 294
 295 /* Number of ifb devices to be set up by this module.
 296  * Note that these legacy devices have one queue.
 297  * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
 298  */
 299 static int numifbs = 2;
 300 module_param(numifbs, int, 0);
 301 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 302
 303 static int __init ifb_init_one(int index)
 304 {
 305         struct net_device *dev_ifb;
 306         int err;
 307
 308         dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
 309                                NET_NAME_UNKNOWN, ifb_setup);
 310
 311         if (!dev_ifb)
 312                 return -ENOMEM;
 313
 314         dev_ifb->rtnl_link_ops = &ifb_link_ops;
 315         err = register_netdevice(dev_ifb);
 316         if (err < 0)
 317                 goto err;
 318
 319         return 0;
 320
 321 err:
 322         free_netdev(dev_ifb);
 323         return err;
 324 }
 325
 326 static int __init ifb_init_module(void)
 327 {
 328         int i, err;
 329
 330         down_write(&pernet_ops_rwsem);
 331         rtnl_lock();
 332         err = __rtnl_link_register(&ifb_link_ops);
 333         if (err < 0)
 334                 goto out;
 335
 336         for (i = 0; i < numifbs && !err; i++) {
 337                 err = ifb_init_one(i);
 338                 cond_resched();
 339         }
 340         if (err)
 341                 __rtnl_link_unregister(&ifb_link_ops);
 342
 343 out:
 344         rtnl_unlock();
 345         up_write(&pernet_ops_rwsem);
 346
 347         return err;
 348 }
 349
 350 static void __exit ifb_cleanup_module(void)
 351 {
 352         rtnl_link_unregister(&ifb_link_ops);
 353 }
 354
 355 module_init(ifb_init_module);
 356 module_exit(ifb_cleanup_module);
 357 MODULE_LICENSE("GPL");
 358 MODULE_AUTHOR("Jamal Hadi Salim");
 359 MODULE_ALIAS_RTNL_LINK("ifb");