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_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \ 191 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \ 192 NETIF_F_HW_VLAN_STAG_TX) 193 194 static void ifb_dev_free(struct net_device *dev) 195 { 196 struct ifb_dev_private *dp = netdev_priv(dev); 197 struct ifb_q_private *txp = dp->tx_private; 198 int i; 199 200 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 201 tasklet_kill(&txp->ifb_tasklet); 202 __skb_queue_purge(&txp->rq); 203 __skb_queue_purge(&txp->tq); 204 } 205 kfree(dp->tx_private); 206 } 207 208 static void ifb_setup(struct net_device *dev) 209 { 210 /* Initialize the device structure. */ 211 dev->netdev_ops = &ifb_netdev_ops; 212 213 /* Fill in device structure with ethernet-generic values. */ 214 ether_setup(dev); 215 dev->tx_queue_len = TX_Q_LIMIT; 216 217 dev->features |= IFB_FEATURES; 218 dev->hw_features |= dev->features; 219 dev->hw_enc_features |= dev->features; 220 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX | 221 NETIF_F_HW_VLAN_STAG_TX); 222 223 dev->flags |= IFF_NOARP; 224 dev->flags &= ~IFF_MULTICAST; 225 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 226 netif_keep_dst(dev); 227 eth_hw_addr_random(dev); 228 dev->needs_free_netdev = true; 229 dev->priv_destructor = ifb_dev_free; 230 231 dev->min_mtu = 0; 232 dev->max_mtu = 0; 233 } 234 235 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 236 { 237 struct ifb_dev_private *dp = netdev_priv(dev); 238 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb); 239 240 u64_stats_update_begin(&txp->rsync); 241 txp->rx_packets++; 242 txp->rx_bytes += skb->len; 243 u64_stats_update_end(&txp->rsync); 244 245 if (!skb->redirected || !skb->skb_iif) { 246 dev_kfree_skb(skb); 247 dev->stats.rx_dropped++; 248 return NETDEV_TX_OK; 249 } 250 251 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len) 252 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum)); 253 254 __skb_queue_tail(&txp->rq, skb); 255 if (!txp->tasklet_pending) { 256 txp->tasklet_pending = 1; 257 tasklet_schedule(&txp->ifb_tasklet); 258 } 259 260 return NETDEV_TX_OK; 261 } 262 263 static int ifb_close(struct net_device *dev) 264 { 265 netif_tx_stop_all_queues(dev); 266 return 0; 267 } 268 269 static int ifb_open(struct net_device *dev) 270 { 271 netif_tx_start_all_queues(dev); 272 return 0; 273 } 274 275 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[], 276 struct netlink_ext_ack *extack) 277 { 278 if (tb[IFLA_ADDRESS]) { 279 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 280 return -EINVAL; 281 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 282 return -EADDRNOTAVAIL; 283 } 284 return 0; 285 } 286 287 static struct rtnl_link_ops ifb_link_ops __read_mostly = { 288 .kind = "ifb", 289 .priv_size = sizeof(struct ifb_dev_private), 290 .setup = ifb_setup, 291 .validate = ifb_validate, 292 }; 293 294 /* Number of ifb devices to be set up by this module. 295 * Note that these legacy devices have one queue. 296 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb 297 */ 298 static int numifbs = 2; 299 module_param(numifbs, int, 0); 300 MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 301 302 static int __init ifb_init_one(int index) 303 { 304 struct net_device *dev_ifb; 305 int err; 306 307 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d", 308 NET_NAME_UNKNOWN, ifb_setup); 309 310 if (!dev_ifb) 311 return -ENOMEM; 312 313 dev_ifb->rtnl_link_ops = &ifb_link_ops; 314 err = register_netdevice(dev_ifb); 315 if (err < 0) 316 goto err; 317 318 return 0; 319 320 err: 321 free_netdev(dev_ifb); 322 return err; 323 } 324 325 static int __init ifb_init_module(void) 326 { 327 int i, err; 328 329 down_write(&pernet_ops_rwsem); 330 rtnl_lock(); 331 err = __rtnl_link_register(&ifb_link_ops); 332 if (err < 0) 333 goto out; 334 335 for (i = 0; i < numifbs && !err; i++) { 336 err = ifb_init_one(i); 337 cond_resched(); 338 } 339 if (err) 340 __rtnl_link_unregister(&ifb_link_ops); 341 342 out: 343 rtnl_unlock(); 344 up_write(&pernet_ops_rwsem); 345 346 return err; 347 } 348 349 static void __exit ifb_cleanup_module(void) 350 { 351 rtnl_link_unregister(&ifb_link_ops); 352 } 353 354 module_init(ifb_init_module); 355 module_exit(ifb_cleanup_module); 356 MODULE_LICENSE("GPL"); 357 MODULE_AUTHOR("Jamal Hadi Salim"); 358 MODULE_ALIAS_RTNL_LINK("ifb"); 359