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
ifb_ri_tasklet(unsigned long _txp)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->tc_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->tc_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
ifb_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats)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
ifb_dev_init(struct net_device * dev)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_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \
191 NETIF_F_GSO_ENCAP_ALL | \
192 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
193 NETIF_F_HW_VLAN_STAG_TX)
194
ifb_dev_free(struct net_device * dev)195 static void ifb_dev_free(struct net_device *dev)
196 {
197 struct ifb_dev_private *dp = netdev_priv(dev);
198 struct ifb_q_private *txp = dp->tx_private;
199 int i;
200
201 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
202 tasklet_kill(&txp->ifb_tasklet);
203 __skb_queue_purge(&txp->rq);
204 __skb_queue_purge(&txp->tq);
205 }
206 kfree(dp->tx_private);
207 }
208
ifb_setup(struct net_device * dev)209 static void ifb_setup(struct net_device *dev)
210 {
211 /* Initialize the device structure. */
212 dev->netdev_ops = &ifb_netdev_ops;
213
214 /* Fill in device structure with ethernet-generic values. */
215 ether_setup(dev);
216 dev->tx_queue_len = TX_Q_LIMIT;
217
218 dev->features |= IFB_FEATURES;
219 dev->hw_features |= dev->features;
220 dev->hw_enc_features |= dev->features;
221 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
222 NETIF_F_HW_VLAN_STAG_TX);
223
224 dev->flags |= IFF_NOARP;
225 dev->flags &= ~IFF_MULTICAST;
226 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
227 netif_keep_dst(dev);
228 eth_hw_addr_random(dev);
229 dev->needs_free_netdev = true;
230 dev->priv_destructor = ifb_dev_free;
231
232 dev->min_mtu = 0;
233 dev->max_mtu = 0;
234 }
235
ifb_xmit(struct sk_buff * skb,struct net_device * dev)236 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
237 {
238 struct ifb_dev_private *dp = netdev_priv(dev);
239 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
240
241 u64_stats_update_begin(&txp->rsync);
242 txp->rx_packets++;
243 txp->rx_bytes += skb->len;
244 u64_stats_update_end(&txp->rsync);
245
246 if (!skb->tc_redirected || !skb->skb_iif) {
247 dev_kfree_skb(skb);
248 dev->stats.rx_dropped++;
249 return NETDEV_TX_OK;
250 }
251
252 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
253 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
254
255 __skb_queue_tail(&txp->rq, skb);
256 if (!txp->tasklet_pending) {
257 txp->tasklet_pending = 1;
258 tasklet_schedule(&txp->ifb_tasklet);
259 }
260
261 return NETDEV_TX_OK;
262 }
263
ifb_close(struct net_device * dev)264 static int ifb_close(struct net_device *dev)
265 {
266 netif_tx_stop_all_queues(dev);
267 return 0;
268 }
269
ifb_open(struct net_device * dev)270 static int ifb_open(struct net_device *dev)
271 {
272 netif_tx_start_all_queues(dev);
273 return 0;
274 }
275
ifb_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)276 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
277 struct netlink_ext_ack *extack)
278 {
279 if (tb[IFLA_ADDRESS]) {
280 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
281 return -EINVAL;
282 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
283 return -EADDRNOTAVAIL;
284 }
285 return 0;
286 }
287
288 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
289 .kind = "ifb",
290 .priv_size = sizeof(struct ifb_dev_private),
291 .setup = ifb_setup,
292 .validate = ifb_validate,
293 };
294
295 /* Number of ifb devices to be set up by this module.
296 * Note that these legacy devices have one queue.
297 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
298 */
299 static int numifbs = 2;
300 module_param(numifbs, int, 0);
301 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
302
ifb_init_one(int index)303 static int __init ifb_init_one(int index)
304 {
305 struct net_device *dev_ifb;
306 int err;
307
308 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
309 NET_NAME_UNKNOWN, ifb_setup);
310
311 if (!dev_ifb)
312 return -ENOMEM;
313
314 dev_ifb->rtnl_link_ops = &ifb_link_ops;
315 err = register_netdevice(dev_ifb);
316 if (err < 0)
317 goto err;
318
319 return 0;
320
321 err:
322 free_netdev(dev_ifb);
323 return err;
324 }
325
ifb_init_module(void)326 static int __init ifb_init_module(void)
327 {
328 int i, err;
329
330 down_write(&pernet_ops_rwsem);
331 rtnl_lock();
332 err = __rtnl_link_register(&ifb_link_ops);
333 if (err < 0)
334 goto out;
335
336 for (i = 0; i < numifbs && !err; i++) {
337 err = ifb_init_one(i);
338 cond_resched();
339 }
340 if (err)
341 __rtnl_link_unregister(&ifb_link_ops);
342
343 out:
344 rtnl_unlock();
345 up_write(&pernet_ops_rwsem);
346
347 return err;
348 }
349
ifb_cleanup_module(void)350 static void __exit ifb_cleanup_module(void)
351 {
352 rtnl_link_unregister(&ifb_link_ops);
353 }
354
355 module_init(ifb_init_module);
356 module_exit(ifb_cleanup_module);
357 MODULE_LICENSE("GPL");
358 MODULE_AUTHOR("Jamal Hadi Salim");
359 MODULE_ALIAS_RTNL_LINK("ifb");
360