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 skb->tc_redirected = 0; 82 skb->tc_skip_classify = 1; 83 84 u64_stats_update_begin(&txp->tsync); 85 txp->tx_packets++; 86 txp->tx_bytes += skb->len; 87 u64_stats_update_end(&txp->tsync); 88 89 rcu_read_lock(); 90 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif); 91 if (!skb->dev) { 92 rcu_read_unlock(); 93 dev_kfree_skb(skb); 94 txp->dev->stats.tx_dropped++; 95 if (skb_queue_len(&txp->tq) != 0) 96 goto resched; 97 break; 98 } 99 rcu_read_unlock(); 100 skb->skb_iif = txp->dev->ifindex; 101 102 if (!skb->tc_from_ingress) { 103 dev_queue_xmit(skb); 104 } else { 105 skb_pull(skb, skb->mac_len); 106 netif_receive_skb(skb); 107 } 108 } 109 110 if (__netif_tx_trylock(txq)) { 111 skb = skb_peek(&txp->rq); 112 if (!skb) { 113 txp->tasklet_pending = 0; 114 if (netif_tx_queue_stopped(txq)) 115 netif_tx_wake_queue(txq); 116 } else { 117 __netif_tx_unlock(txq); 118 goto resched; 119 } 120 __netif_tx_unlock(txq); 121 } else { 122 resched: 123 txp->tasklet_pending = 1; 124 tasklet_schedule(&txp->ifb_tasklet); 125 } 126 127 } 128 129 static void ifb_stats64(struct net_device *dev, 130 struct rtnl_link_stats64 *stats) 131 { 132 struct ifb_dev_private *dp = netdev_priv(dev); 133 struct ifb_q_private *txp = dp->tx_private; 134 unsigned int start; 135 u64 packets, bytes; 136 int i; 137 138 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 139 do { 140 start = u64_stats_fetch_begin_irq(&txp->rsync); 141 packets = txp->rx_packets; 142 bytes = txp->rx_bytes; 143 } while (u64_stats_fetch_retry_irq(&txp->rsync, start)); 144 stats->rx_packets += packets; 145 stats->rx_bytes += bytes; 146 147 do { 148 start = u64_stats_fetch_begin_irq(&txp->tsync); 149 packets = txp->tx_packets; 150 bytes = txp->tx_bytes; 151 } while (u64_stats_fetch_retry_irq(&txp->tsync, start)); 152 stats->tx_packets += packets; 153 stats->tx_bytes += bytes; 154 } 155 stats->rx_dropped = dev->stats.rx_dropped; 156 stats->tx_dropped = dev->stats.tx_dropped; 157 } 158 159 static int ifb_dev_init(struct net_device *dev) 160 { 161 struct ifb_dev_private *dp = netdev_priv(dev); 162 struct ifb_q_private *txp; 163 int i; 164 165 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL); 166 if (!txp) 167 return -ENOMEM; 168 dp->tx_private = txp; 169 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 170 txp->txqnum = i; 171 txp->dev = dev; 172 __skb_queue_head_init(&txp->rq); 173 __skb_queue_head_init(&txp->tq); 174 u64_stats_init(&txp->rsync); 175 u64_stats_init(&txp->tsync); 176 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet, 177 (unsigned long)txp); 178 netif_tx_start_queue(netdev_get_tx_queue(dev, i)); 179 } 180 return 0; 181 } 182 183 static const struct net_device_ops ifb_netdev_ops = { 184 .ndo_open = ifb_open, 185 .ndo_stop = ifb_close, 186 .ndo_get_stats64 = ifb_stats64, 187 .ndo_start_xmit = ifb_xmit, 188 .ndo_validate_addr = eth_validate_addr, 189 .ndo_init = ifb_dev_init, 190 }; 191 192 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \ 193 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \ 194 NETIF_F_GSO_ENCAP_ALL | \ 195 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \ 196 NETIF_F_HW_VLAN_STAG_TX) 197 198 static void ifb_dev_free(struct net_device *dev) 199 { 200 struct ifb_dev_private *dp = netdev_priv(dev); 201 struct ifb_q_private *txp = dp->tx_private; 202 int i; 203 204 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 205 tasklet_kill(&txp->ifb_tasklet); 206 __skb_queue_purge(&txp->rq); 207 __skb_queue_purge(&txp->tq); 208 } 209 kfree(dp->tx_private); 210 } 211 212 static void ifb_setup(struct net_device *dev) 213 { 214 /* Initialize the device structure. */ 215 dev->netdev_ops = &ifb_netdev_ops; 216 217 /* Fill in device structure with ethernet-generic values. */ 218 ether_setup(dev); 219 dev->tx_queue_len = TX_Q_LIMIT; 220 221 dev->features |= IFB_FEATURES; 222 dev->hw_features |= dev->features; 223 dev->hw_enc_features |= dev->features; 224 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX | 225 NETIF_F_HW_VLAN_STAG_TX); 226 227 dev->flags |= IFF_NOARP; 228 dev->flags &= ~IFF_MULTICAST; 229 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 230 netif_keep_dst(dev); 231 eth_hw_addr_random(dev); 232 dev->needs_free_netdev = true; 233 dev->priv_destructor = ifb_dev_free; 234 235 dev->min_mtu = 0; 236 dev->max_mtu = 0; 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_redirected || !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 struct netlink_ext_ack *extack) 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