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_q_private { 42 struct net_device *dev; 43 struct tasklet_struct ifb_tasklet; 44 int tasklet_pending; 45 int txqnum; 46 struct sk_buff_head rq; 47 u64 rx_packets; 48 u64 rx_bytes; 49 struct u64_stats_sync rsync; 50 51 struct u64_stats_sync tsync; 52 u64 tx_packets; 53 u64 tx_bytes; 54 struct sk_buff_head tq; 55 } ____cacheline_aligned_in_smp; 56 57 struct ifb_dev_private { 58 struct ifb_q_private *tx_private; 59 }; 60 61 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev); 62 static int ifb_open(struct net_device *dev); 63 static int ifb_close(struct net_device *dev); 64 65 static void ifb_ri_tasklet(unsigned long _txp) 66 { 67 struct ifb_q_private *txp = (struct ifb_q_private *)_txp; 68 struct netdev_queue *txq; 69 struct sk_buff *skb; 70 71 txq = netdev_get_tx_queue(txp->dev, txp->txqnum); 72 skb = skb_peek(&txp->tq); 73 if (!skb) { 74 if (!__netif_tx_trylock(txq)) 75 goto resched; 76 skb_queue_splice_tail_init(&txp->rq, &txp->tq); 77 __netif_tx_unlock(txq); 78 } 79 80 while ((skb = __skb_dequeue(&txp->tq)) != NULL) { 81 u32 from = skb->tc_from; 82 83 skb_reset_tc(skb); 84 skb->tc_skip_classify = 1; 85 86 u64_stats_update_begin(&txp->tsync); 87 txp->tx_packets++; 88 txp->tx_bytes += skb->len; 89 u64_stats_update_end(&txp->tsync); 90 91 rcu_read_lock(); 92 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif); 93 if (!skb->dev) { 94 rcu_read_unlock(); 95 dev_kfree_skb(skb); 96 txp->dev->stats.tx_dropped++; 97 if (skb_queue_len(&txp->tq) != 0) 98 goto resched; 99 break; 100 } 101 rcu_read_unlock(); 102 skb->skb_iif = txp->dev->ifindex; 103 104 if (from & AT_EGRESS) { 105 dev_queue_xmit(skb); 106 } else if (from & AT_INGRESS) { 107 skb_pull(skb, skb->mac_len); 108 netif_receive_skb(skb); 109 } else 110 BUG(); 111 } 112 113 if (__netif_tx_trylock(txq)) { 114 skb = skb_peek(&txp->rq); 115 if (!skb) { 116 txp->tasklet_pending = 0; 117 if (netif_tx_queue_stopped(txq)) 118 netif_tx_wake_queue(txq); 119 } else { 120 __netif_tx_unlock(txq); 121 goto resched; 122 } 123 __netif_tx_unlock(txq); 124 } else { 125 resched: 126 txp->tasklet_pending = 1; 127 tasklet_schedule(&txp->ifb_tasklet); 128 } 129 130 } 131 132 static void ifb_stats64(struct net_device *dev, 133 struct rtnl_link_stats64 *stats) 134 { 135 struct ifb_dev_private *dp = netdev_priv(dev); 136 struct ifb_q_private *txp = dp->tx_private; 137 unsigned int start; 138 u64 packets, bytes; 139 int i; 140 141 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 142 do { 143 start = u64_stats_fetch_begin_irq(&txp->rsync); 144 packets = txp->rx_packets; 145 bytes = txp->rx_bytes; 146 } while (u64_stats_fetch_retry_irq(&txp->rsync, start)); 147 stats->rx_packets += packets; 148 stats->rx_bytes += bytes; 149 150 do { 151 start = u64_stats_fetch_begin_irq(&txp->tsync); 152 packets = txp->tx_packets; 153 bytes = txp->tx_bytes; 154 } while (u64_stats_fetch_retry_irq(&txp->tsync, start)); 155 stats->tx_packets += packets; 156 stats->tx_bytes += bytes; 157 } 158 stats->rx_dropped = dev->stats.rx_dropped; 159 stats->tx_dropped = dev->stats.tx_dropped; 160 } 161 162 static int ifb_dev_init(struct net_device *dev) 163 { 164 struct ifb_dev_private *dp = netdev_priv(dev); 165 struct ifb_q_private *txp; 166 int i; 167 168 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL); 169 if (!txp) 170 return -ENOMEM; 171 dp->tx_private = txp; 172 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 173 txp->txqnum = i; 174 txp->dev = dev; 175 __skb_queue_head_init(&txp->rq); 176 __skb_queue_head_init(&txp->tq); 177 u64_stats_init(&txp->rsync); 178 u64_stats_init(&txp->tsync); 179 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet, 180 (unsigned long)txp); 181 netif_tx_start_queue(netdev_get_tx_queue(dev, i)); 182 } 183 return 0; 184 } 185 186 static const struct net_device_ops ifb_netdev_ops = { 187 .ndo_open = ifb_open, 188 .ndo_stop = ifb_close, 189 .ndo_get_stats64 = ifb_stats64, 190 .ndo_start_xmit = ifb_xmit, 191 .ndo_validate_addr = eth_validate_addr, 192 .ndo_init = ifb_dev_init, 193 }; 194 195 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \ 196 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \ 197 NETIF_F_GSO_ENCAP_ALL | \ 198 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \ 199 NETIF_F_HW_VLAN_STAG_TX) 200 201 static void ifb_dev_free(struct net_device *dev) 202 { 203 struct ifb_dev_private *dp = netdev_priv(dev); 204 struct ifb_q_private *txp = dp->tx_private; 205 int i; 206 207 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 208 tasklet_kill(&txp->ifb_tasklet); 209 __skb_queue_purge(&txp->rq); 210 __skb_queue_purge(&txp->tq); 211 } 212 kfree(dp->tx_private); 213 free_netdev(dev); 214 } 215 216 static void ifb_setup(struct net_device *dev) 217 { 218 /* Initialize the device structure. */ 219 dev->netdev_ops = &ifb_netdev_ops; 220 221 /* Fill in device structure with ethernet-generic values. */ 222 ether_setup(dev); 223 dev->tx_queue_len = TX_Q_LIMIT; 224 225 dev->features |= IFB_FEATURES; 226 dev->hw_features |= dev->features; 227 dev->hw_enc_features |= dev->features; 228 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX | 229 NETIF_F_HW_VLAN_STAG_TX); 230 231 dev->flags |= IFF_NOARP; 232 dev->flags &= ~IFF_MULTICAST; 233 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 234 netif_keep_dst(dev); 235 eth_hw_addr_random(dev); 236 dev->destructor = ifb_dev_free; 237 } 238 239 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 240 { 241 struct ifb_dev_private *dp = netdev_priv(dev); 242 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb); 243 244 u64_stats_update_begin(&txp->rsync); 245 txp->rx_packets++; 246 txp->rx_bytes += skb->len; 247 u64_stats_update_end(&txp->rsync); 248 249 if (skb->tc_from == AT_STACK || !skb->skb_iif) { 250 dev_kfree_skb(skb); 251 dev->stats.rx_dropped++; 252 return NETDEV_TX_OK; 253 } 254 255 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len) 256 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum)); 257 258 __skb_queue_tail(&txp->rq, skb); 259 if (!txp->tasklet_pending) { 260 txp->tasklet_pending = 1; 261 tasklet_schedule(&txp->ifb_tasklet); 262 } 263 264 return NETDEV_TX_OK; 265 } 266 267 static int ifb_close(struct net_device *dev) 268 { 269 netif_tx_stop_all_queues(dev); 270 return 0; 271 } 272 273 static int ifb_open(struct net_device *dev) 274 { 275 netif_tx_start_all_queues(dev); 276 return 0; 277 } 278 279 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 280 { 281 if (tb[IFLA_ADDRESS]) { 282 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 283 return -EINVAL; 284 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 285 return -EADDRNOTAVAIL; 286 } 287 return 0; 288 } 289 290 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 291 .kind = "ifb", 292 .priv_size = sizeof(struct ifb_dev_private), 293 .setup = ifb_setup, 294 .validate = ifb_validate, 295 }; 296 297 /* Number of ifb devices to be set up by this module. 298 * Note that these legacy devices have one queue. 299 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb 300 */ 301 static int numifbs = 2; 302 module_param(numifbs, int, 0); 303 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 304 305 static int __init ifb_init_one(int index) 306 { 307 struct net_device *dev_ifb; 308 int err; 309 310 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d", 311 NET_NAME_UNKNOWN, ifb_setup); 312 313 if (!dev_ifb) 314 return -ENOMEM; 315 316 dev_ifb->rtnl_link_ops = &ifb_link_ops; 317 err = register_netdevice(dev_ifb); 318 if (err < 0) 319 goto err; 320 321 return 0; 322 323 err: 324 free_netdev(dev_ifb); 325 return err; 326 } 327 328 static int __init ifb_init_module(void) 329 { 330 int i, err; 331 332 rtnl_lock(); 333 err = __rtnl_link_register(&ifb_link_ops); 334 if (err < 0) 335 goto out; 336 337 for (i = 0; i < numifbs && !err; i++) { 338 err = ifb_init_one(i); 339 cond_resched(); 340 } 341 if (err) 342 __rtnl_link_unregister(&ifb_link_ops); 343 344 out: 345 rtnl_unlock(); 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"); 360