1 // SPDX-License-Identifier: GPL-2.0-or-later
4 The purpose of this driver is to provide a device that allows
5 for sharing of resources:
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.
11 2) Allows for queueing incoming traffic for shaping instead of
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.
18 You need the tc action mirror or redirect to feed this device
22 Authors: Jamal Hadi Salim (2005)
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>
38 struct ifb_q_private {
39 struct net_device *dev;
40 struct tasklet_struct ifb_tasklet;
43 struct sk_buff_head rq;
46 struct u64_stats_sync rsync;
48 struct u64_stats_sync tsync;
51 struct sk_buff_head tq;
52 } ____cacheline_aligned_in_smp;
54 struct ifb_dev_private {
55 struct ifb_q_private *tx_private;
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);
62 static void ifb_ri_tasklet(unsigned long _txp)
64 struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
65 struct netdev_queue *txq;
68 txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
69 skb = skb_peek(&txp->tq);
71 if (!__netif_tx_trylock(txq))
73 skb_queue_splice_tail_init(&txp->rq, &txp->tq);
74 __netif_tx_unlock(txq);
77 while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
79 skb->tc_skip_classify = 1;
81 u64_stats_update_begin(&txp->tsync);
83 txp->tx_bytes += skb->len;
84 u64_stats_update_end(&txp->tsync);
87 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
91 txp->dev->stats.tx_dropped++;
92 if (skb_queue_len(&txp->tq) != 0)
97 skb->skb_iif = txp->dev->ifindex;
99 if (!skb->from_ingress) {
102 skb_pull_rcsum(skb, skb->mac_len);
103 netif_receive_skb(skb);
107 if (__netif_tx_trylock(txq)) {
108 skb = skb_peek(&txp->rq);
110 txp->tasklet_pending = 0;
111 if (netif_tx_queue_stopped(txq))
112 netif_tx_wake_queue(txq);
114 __netif_tx_unlock(txq);
117 __netif_tx_unlock(txq);
120 txp->tasklet_pending = 1;
121 tasklet_schedule(&txp->ifb_tasklet);
126 static void ifb_stats64(struct net_device *dev,
127 struct rtnl_link_stats64 *stats)
129 struct ifb_dev_private *dp = netdev_priv(dev);
130 struct ifb_q_private *txp = dp->tx_private;
135 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
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;
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;
152 stats->rx_dropped = dev->stats.rx_dropped;
153 stats->tx_dropped = dev->stats.tx_dropped;
156 static int ifb_dev_init(struct net_device *dev)
158 struct ifb_dev_private *dp = netdev_priv(dev);
159 struct ifb_q_private *txp;
162 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
165 dp->tx_private = txp;
166 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
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,
175 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
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,
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)
194 static void ifb_dev_free(struct net_device *dev)
196 struct ifb_dev_private *dp = netdev_priv(dev);
197 struct ifb_q_private *txp = dp->tx_private;
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);
205 kfree(dp->tx_private);
208 static void ifb_setup(struct net_device *dev)
210 /* Initialize the device structure. */
211 dev->netdev_ops = &ifb_netdev_ops;
213 /* Fill in device structure with ethernet-generic values. */
215 dev->tx_queue_len = TX_Q_LIMIT;
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);
223 dev->flags |= IFF_NOARP;
224 dev->flags &= ~IFF_MULTICAST;
225 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
227 eth_hw_addr_random(dev);
228 dev->needs_free_netdev = true;
229 dev->priv_destructor = ifb_dev_free;
235 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
237 struct ifb_dev_private *dp = netdev_priv(dev);
238 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
240 u64_stats_update_begin(&txp->rsync);
242 txp->rx_bytes += skb->len;
243 u64_stats_update_end(&txp->rsync);
245 if (!skb->redirected || !skb->skb_iif) {
247 dev->stats.rx_dropped++;
251 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
252 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
254 __skb_queue_tail(&txp->rq, skb);
255 if (!txp->tasklet_pending) {
256 txp->tasklet_pending = 1;
257 tasklet_schedule(&txp->ifb_tasklet);
263 static int ifb_close(struct net_device *dev)
265 netif_tx_stop_all_queues(dev);
269 static int ifb_open(struct net_device *dev)
271 netif_tx_start_all_queues(dev);
275 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
276 struct netlink_ext_ack *extack)
278 if (tb[IFLA_ADDRESS]) {
279 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
281 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
282 return -EADDRNOTAVAIL;
287 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
289 .priv_size = sizeof(struct ifb_dev_private),
291 .validate = ifb_validate,
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
298 static int numifbs = 2;
299 module_param(numifbs, int, 0);
300 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
302 static int __init ifb_init_one(int index)
304 struct net_device *dev_ifb;
307 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
308 NET_NAME_UNKNOWN, ifb_setup);
313 dev_ifb->rtnl_link_ops = &ifb_link_ops;
314 err = register_netdevice(dev_ifb);
321 free_netdev(dev_ifb);
325 static int __init ifb_init_module(void)
329 down_write(&pernet_ops_rwsem);
331 err = __rtnl_link_register(&ifb_link_ops);
335 for (i = 0; i < numifbs && !err; i++) {
336 err = ifb_init_one(i);
340 __rtnl_link_unregister(&ifb_link_ops);
344 up_write(&pernet_ops_rwsem);
349 static void __exit ifb_cleanup_module(void)
351 rtnl_link_unregister(&ifb_link_ops);
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");