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 = G_TC_FROM(skb->tc_verd); 82 83 skb->tc_verd = 0; 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 u32 from = G_TC_FROM(skb->tc_verd); 243 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb); 244 245 u64_stats_update_begin(&txp->rsync); 246 txp->rx_packets++; 247 txp->rx_bytes += skb->len; 248 u64_stats_update_end(&txp->rsync); 249 250 if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->skb_iif) { 251 dev_kfree_skb(skb); 252 dev->stats.rx_dropped++; 253 return NETDEV_TX_OK; 254 } 255 256 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len) 257 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum)); 258 259 __skb_queue_tail(&txp->rq, skb); 260 if (!txp->tasklet_pending) { 261 txp->tasklet_pending = 1; 262 tasklet_schedule(&txp->ifb_tasklet); 263 } 264 265 return NETDEV_TX_OK; 266 } 267 268 static int ifb_close(struct net_device *dev) 269 { 270 netif_tx_stop_all_queues(dev); 271 return 0; 272 } 273 274 static int ifb_open(struct net_device *dev) 275 { 276 netif_tx_start_all_queues(dev); 277 return 0; 278 } 279 280 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[]) 281 { 282 if (tb[IFLA_ADDRESS]) { 283 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 284 return -EINVAL; 285 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 286 return -EADDRNOTAVAIL; 287 } 288 return 0; 289 } 290 291 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 292 .kind = "ifb", 293 .priv_size = sizeof(struct ifb_dev_private), 294 .setup = ifb_setup, 295 .validate = ifb_validate, 296 }; 297 298 /* Number of ifb devices to be set up by this module. 299 * Note that these legacy devices have one queue. 300 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb 301 */ 302 static int numifbs = 2; 303 module_param(numifbs, int, 0); 304 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 305 306 static int __init ifb_init_one(int index) 307 { 308 struct net_device *dev_ifb; 309 int err; 310 311 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d", 312 NET_NAME_UNKNOWN, ifb_setup); 313 314 if (!dev_ifb) 315 return -ENOMEM; 316 317 dev_ifb->rtnl_link_ops = &ifb_link_ops; 318 err = register_netdevice(dev_ifb); 319 if (err < 0) 320 goto err; 321 322 return 0; 323 324 err: 325 free_netdev(dev_ifb); 326 return err; 327 } 328 329 static int __init ifb_init_module(void) 330 { 331 int i, err; 332 333 rtnl_lock(); 334 err = __rtnl_link_register(&ifb_link_ops); 335 if (err < 0) 336 goto out; 337 338 for (i = 0; i < numifbs && !err; i++) { 339 err = ifb_init_one(i); 340 cond_resched(); 341 } 342 if (err) 343 __rtnl_link_unregister(&ifb_link_ops); 344 345 out: 346 rtnl_unlock(); 347 348 return err; 349 } 350 351 static void __exit ifb_cleanup_module(void) 352 { 353 rtnl_link_unregister(&ifb_link_ops); 354 } 355 356 module_init(ifb_init_module); 357 module_exit(ifb_cleanup_module); 358 MODULE_LICENSE("GPL"); 359 MODULE_AUTHOR("Jamal Hadi Salim"); 360 MODULE_ALIAS_RTNL_LINK("ifb"); 361