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(struct tasklet_struct * t)62 static void ifb_ri_tasklet(struct tasklet_struct *t)
63 {
64 struct ifb_q_private *txp = from_tasklet(txp, t, ifb_tasklet);
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
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_setup(&txp->ifb_tasklet, ifb_ri_tasklet);
174 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
175 }
176 return 0;
177 }
178
179 static const struct net_device_ops ifb_netdev_ops = {
180 .ndo_open = ifb_open,
181 .ndo_stop = ifb_close,
182 .ndo_get_stats64 = ifb_stats64,
183 .ndo_start_xmit = ifb_xmit,
184 .ndo_validate_addr = eth_validate_addr,
185 .ndo_init = ifb_dev_init,
186 };
187
188 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \
189 NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
190 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
191 NETIF_F_HW_VLAN_STAG_TX)
192
ifb_dev_free(struct net_device * dev)193 static void ifb_dev_free(struct net_device *dev)
194 {
195 struct ifb_dev_private *dp = netdev_priv(dev);
196 struct ifb_q_private *txp = dp->tx_private;
197 int i;
198
199 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
200 tasklet_kill(&txp->ifb_tasklet);
201 __skb_queue_purge(&txp->rq);
202 __skb_queue_purge(&txp->tq);
203 }
204 kfree(dp->tx_private);
205 }
206
ifb_setup(struct net_device * dev)207 static void ifb_setup(struct net_device *dev)
208 {
209 /* Initialize the device structure. */
210 dev->netdev_ops = &ifb_netdev_ops;
211
212 /* Fill in device structure with ethernet-generic values. */
213 ether_setup(dev);
214 dev->tx_queue_len = TX_Q_LIMIT;
215
216 dev->features |= IFB_FEATURES;
217 dev->hw_features |= dev->features;
218 dev->hw_enc_features |= dev->features;
219 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
220 NETIF_F_HW_VLAN_STAG_TX);
221
222 dev->flags |= IFF_NOARP;
223 dev->flags &= ~IFF_MULTICAST;
224 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
225 netif_keep_dst(dev);
226 eth_hw_addr_random(dev);
227 dev->needs_free_netdev = true;
228 dev->priv_destructor = ifb_dev_free;
229
230 dev->min_mtu = 0;
231 dev->max_mtu = 0;
232 }
233
ifb_xmit(struct sk_buff * skb,struct net_device * dev)234 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
235 {
236 struct ifb_dev_private *dp = netdev_priv(dev);
237 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
238
239 u64_stats_update_begin(&txp->rsync);
240 txp->rx_packets++;
241 txp->rx_bytes += skb->len;
242 u64_stats_update_end(&txp->rsync);
243
244 if (!skb->redirected || !skb->skb_iif) {
245 dev_kfree_skb(skb);
246 dev->stats.rx_dropped++;
247 return NETDEV_TX_OK;
248 }
249
250 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
251 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
252
253 __skb_queue_tail(&txp->rq, skb);
254 if (!txp->tasklet_pending) {
255 txp->tasklet_pending = 1;
256 tasklet_schedule(&txp->ifb_tasklet);
257 }
258
259 return NETDEV_TX_OK;
260 }
261
ifb_close(struct net_device * dev)262 static int ifb_close(struct net_device *dev)
263 {
264 netif_tx_stop_all_queues(dev);
265 return 0;
266 }
267
ifb_open(struct net_device * dev)268 static int ifb_open(struct net_device *dev)
269 {
270 netif_tx_start_all_queues(dev);
271 return 0;
272 }
273
ifb_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)274 static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
275 struct netlink_ext_ack *extack)
276 {
277 if (tb[IFLA_ADDRESS]) {
278 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
279 return -EINVAL;
280 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
281 return -EADDRNOTAVAIL;
282 }
283 return 0;
284 }
285
286 static struct rtnl_link_ops ifb_link_ops __read_mostly = {
287 .kind = "ifb",
288 .priv_size = sizeof(struct ifb_dev_private),
289 .setup = ifb_setup,
290 .validate = ifb_validate,
291 };
292
293 /* Number of ifb devices to be set up by this module.
294 * Note that these legacy devices have one queue.
295 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
296 */
297 static int numifbs = 2;
298 module_param(numifbs, int, 0);
299 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
300
ifb_init_one(int index)301 static int __init ifb_init_one(int index)
302 {
303 struct net_device *dev_ifb;
304 int err;
305
306 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
307 NET_NAME_UNKNOWN, ifb_setup);
308
309 if (!dev_ifb)
310 return -ENOMEM;
311
312 dev_ifb->rtnl_link_ops = &ifb_link_ops;
313 err = register_netdevice(dev_ifb);
314 if (err < 0)
315 goto err;
316
317 return 0;
318
319 err:
320 free_netdev(dev_ifb);
321 return err;
322 }
323
ifb_init_module(void)324 static int __init ifb_init_module(void)
325 {
326 int i, err;
327
328 down_write(&pernet_ops_rwsem);
329 rtnl_lock();
330 err = __rtnl_link_register(&ifb_link_ops);
331 if (err < 0)
332 goto out;
333
334 for (i = 0; i < numifbs && !err; i++) {
335 err = ifb_init_one(i);
336 cond_resched();
337 }
338 if (err)
339 __rtnl_link_unregister(&ifb_link_ops);
340
341 out:
342 rtnl_unlock();
343 up_write(&pernet_ops_rwsem);
344
345 return err;
346 }
347
ifb_cleanup_module(void)348 static void __exit ifb_cleanup_module(void)
349 {
350 rtnl_link_unregister(&ifb_link_ops);
351 }
352
353 module_init(ifb_init_module);
354 module_exit(ifb_cleanup_module);
355 MODULE_LICENSE("GPL");
356 MODULE_AUTHOR("Jamal Hadi Salim");
357 MODULE_ALIAS_RTNL_LINK("ifb");
358