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 38struct 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 54struct ifb_dev_private { 55 struct ifb_q_private *tx_private; 56}; 57 58static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev); 59static int ifb_open(struct net_device *dev); 60static int ifb_close(struct net_device *dev); 61 62static 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#ifdef CONFIG_NET_CLS_ACT 80 skb->tc_skip_classify = 1; 81#endif 82 83 u64_stats_update_begin(&txp->tsync); 84 txp->tx_packets++; 85 txp->tx_bytes += skb->len; 86 u64_stats_update_end(&txp->tsync); 87 88 rcu_read_lock(); 89 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif); 90 if (!skb->dev) { 91 rcu_read_unlock(); 92 dev_kfree_skb(skb); 93 txp->dev->stats.tx_dropped++; 94 if (skb_queue_len(&txp->tq) != 0) 95 goto resched; 96 break; 97 } 98 rcu_read_unlock(); 99 skb->skb_iif = txp->dev->ifindex; 100 101 if (!skb->from_ingress) { 102 dev_queue_xmit(skb); 103 } else { 104 skb_pull_rcsum(skb, skb->mac_len); 105 netif_receive_skb(skb); 106 } 107 } 108 109 if (__netif_tx_trylock(txq)) { 110 skb = skb_peek(&txp->rq); 111 if (!skb) { 112 txp->tasklet_pending = 0; 113 if (netif_tx_queue_stopped(txq)) 114 netif_tx_wake_queue(txq); 115 } else { 116 __netif_tx_unlock(txq); 117 goto resched; 118 } 119 __netif_tx_unlock(txq); 120 } else { 121resched: 122 txp->tasklet_pending = 1; 123 tasklet_schedule(&txp->ifb_tasklet); 124 } 125 126} 127 128static void ifb_stats64(struct net_device *dev, 129 struct rtnl_link_stats64 *stats) 130{ 131 struct ifb_dev_private *dp = netdev_priv(dev); 132 struct ifb_q_private *txp = dp->tx_private; 133 unsigned int start; 134 u64 packets, bytes; 135 int i; 136 137 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 138 do { 139 start = u64_stats_fetch_begin_irq(&txp->rsync); 140 packets = txp->rx_packets; 141 bytes = txp->rx_bytes; 142 } while (u64_stats_fetch_retry_irq(&txp->rsync, start)); 143 stats->rx_packets += packets; 144 stats->rx_bytes += bytes; 145 146 do { 147 start = u64_stats_fetch_begin_irq(&txp->tsync); 148 packets = txp->tx_packets; 149 bytes = txp->tx_bytes; 150 } while (u64_stats_fetch_retry_irq(&txp->tsync, start)); 151 stats->tx_packets += packets; 152 stats->tx_bytes += bytes; 153 } 154 stats->rx_dropped = dev->stats.rx_dropped; 155 stats->tx_dropped = dev->stats.tx_dropped; 156} 157 158static int ifb_dev_init(struct net_device *dev) 159{ 160 struct ifb_dev_private *dp = netdev_priv(dev); 161 struct ifb_q_private *txp; 162 int i; 163 164 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL); 165 if (!txp) 166 return -ENOMEM; 167 dp->tx_private = txp; 168 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 169 txp->txqnum = i; 170 txp->dev = dev; 171 __skb_queue_head_init(&txp->rq); 172 __skb_queue_head_init(&txp->tq); 173 u64_stats_init(&txp->rsync); 174 u64_stats_init(&txp->tsync); 175 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet, 176 (unsigned long)txp); 177 netif_tx_start_queue(netdev_get_tx_queue(dev, i)); 178 } 179 return 0; 180} 181 182static const struct net_device_ops ifb_netdev_ops = { 183 .ndo_open = ifb_open, 184 .ndo_stop = ifb_close, 185 .ndo_get_stats64 = ifb_stats64, 186 .ndo_start_xmit = ifb_xmit, 187 .ndo_validate_addr = eth_validate_addr, 188 .ndo_init = ifb_dev_init, 189}; 190 191#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \ 192 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \ 193 NETIF_F_GSO_ENCAP_ALL | \ 194 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \ 195 NETIF_F_HW_VLAN_STAG_TX) 196 197static void ifb_dev_free(struct net_device *dev) 198{ 199 struct ifb_dev_private *dp = netdev_priv(dev); 200 struct ifb_q_private *txp = dp->tx_private; 201 int i; 202 203 for (i = 0; i < dev->num_tx_queues; i++,txp++) { 204 tasklet_kill(&txp->ifb_tasklet); 205 __skb_queue_purge(&txp->rq); 206 __skb_queue_purge(&txp->tq); 207 } 208 kfree(dp->tx_private); 209} 210 211static void ifb_setup(struct net_device *dev) 212{ 213 /* Initialize the device structure. */ 214 dev->netdev_ops = &ifb_netdev_ops; 215 216 /* Fill in device structure with ethernet-generic values. */ 217 ether_setup(dev); 218 dev->tx_queue_len = TX_Q_LIMIT; 219 220 dev->features |= IFB_FEATURES; 221 dev->hw_features |= dev->features; 222 dev->hw_enc_features |= dev->features; 223 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX | 224 NETIF_F_HW_VLAN_STAG_TX); 225 226 dev->flags |= IFF_NOARP; 227 dev->flags &= ~IFF_MULTICAST; 228 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 229 netif_keep_dst(dev); 230 eth_hw_addr_random(dev); 231 dev->needs_free_netdev = true; 232 dev->priv_destructor = ifb_dev_free; 233 234 dev->min_mtu = 0; 235 dev->max_mtu = 0; 236} 237 238static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev) 239{ 240 struct ifb_dev_private *dp = netdev_priv(dev); 241 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb); 242 243 u64_stats_update_begin(&txp->rsync); 244 txp->rx_packets++; 245 txp->rx_bytes += skb->len; 246 u64_stats_update_end(&txp->rsync); 247 248 if (!skb->redirected || !skb->skb_iif) { 249 dev_kfree_skb(skb); 250 dev->stats.rx_dropped++; 251 return NETDEV_TX_OK; 252 } 253 254 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len) 255 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum)); 256 257 __skb_queue_tail(&txp->rq, skb); 258 if (!txp->tasklet_pending) { 259 txp->tasklet_pending = 1; 260 tasklet_schedule(&txp->ifb_tasklet); 261 } 262 263 return NETDEV_TX_OK; 264} 265 266static int ifb_close(struct net_device *dev) 267{ 268 netif_tx_stop_all_queues(dev); 269 return 0; 270} 271 272static int ifb_open(struct net_device *dev) 273{ 274 netif_tx_start_all_queues(dev); 275 return 0; 276} 277 278static int ifb_validate(struct nlattr *tb[], struct nlattr *data[], 279 struct netlink_ext_ack *extack) 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 290static 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 */ 301static int numifbs = 2; 302module_param(numifbs, int, 0); 303MODULE_PARM_DESC(numifbs, "Number of ifb devices"); 304 305static 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 323err: 324 free_netdev(dev_ifb); 325 return err; 326} 327 328static int __init ifb_init_module(void) 329{ 330 int i, err; 331 332 down_write(&pernet_ops_rwsem); 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 345out: 346 rtnl_unlock(); 347 up_write(&pernet_ops_rwsem); 348 349 return err; 350} 351 352static void __exit ifb_cleanup_module(void) 353{ 354 rtnl_link_unregister(&ifb_link_ops); 355} 356 357module_init(ifb_init_module); 358module_exit(ifb_cleanup_module); 359MODULE_LICENSE("GPL"); 360MODULE_AUTHOR("Jamal Hadi Salim"); 361MODULE_ALIAS_RTNL_LINK("ifb"); 362