1/* drivers/net/ifb.c:
2
3 The purpose of this driver is to provide a device that allows
4 for sharing of resources:
5
6 1) qdiscs/policies that are per device as opposed to system wide.
7 ifb allows for a device which can be redirected to thus providing
8 an impression of sharing.
9
10 2) Allows for queueing incoming traffic for shaping instead of
11 dropping.
12
13 The original concept is based on what is known as the IMQ
14 driver initially written by Martin Devera, later rewritten
15 by Patrick McHardy and then maintained by Andre Correa.
16
17 You need the tc action mirror or redirect to feed this device
18 packets.
19
20 This program is free software; you can redistribute it and/or
21 modify it under the terms of the GNU General Public License
22 as published by the Free Software Foundation; either version
23 2 of the License, or (at your option) any later version.
24
25 Authors: Jamal Hadi Salim (2005)
26
27*/
28
29
30#include <linux/module.h>
31#include <linux/kernel.h>
32#include <linux/netdevice.h>
33#include <linux/etherdevice.h>
34#include <linux/init.h>
35#include <linux/interrupt.h>
36#include <linux/moduleparam.h>
37#include <net/pkt_sched.h>
38#include <net/net_namespace.h>
39
40#define TX_Q_LIMIT 32
41struct ifb_q_private {
42 struct net_device *dev;
43 struct tasklet_struct ifb_tasklet;
44 int tasklet_pending;
45 int txqnum;
46 struct sk_buff_head rq;
47 u64 rx_packets;
48 u64 rx_bytes;
49 struct u64_stats_sync rsync;
50
51 struct u64_stats_sync tsync;
52 u64 tx_packets;
53 u64 tx_bytes;
54 struct sk_buff_head tq;
55} ____cacheline_aligned_in_smp;
56
57struct ifb_dev_private {
58 struct ifb_q_private *tx_private;
59};
60
61static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
62static int ifb_open(struct net_device *dev);
63static int ifb_close(struct net_device *dev);
64
65static void ifb_ri_tasklet(unsigned long _txp)
66{
67 struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
68 struct netdev_queue *txq;
69 struct sk_buff *skb;
70
71 txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
72 skb = skb_peek(&txp->tq);
73 if (!skb) {
74 if (!__netif_tx_trylock(txq))
75 goto resched;
76 skb_queue_splice_tail_init(&txp->rq, &txp->tq);
77 __netif_tx_unlock(txq);
78 }
79
80 while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
81 skb->tc_redirected = 0;
82 skb->tc_skip_classify = 1;
83
84 u64_stats_update_begin(&txp->tsync);
85 txp->tx_packets++;
86 txp->tx_bytes += skb->len;
87 u64_stats_update_end(&txp->tsync);
88
89 rcu_read_lock();
90 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
91 if (!skb->dev) {
92 rcu_read_unlock();
93 dev_kfree_skb(skb);
94 txp->dev->stats.tx_dropped++;
95 if (skb_queue_len(&txp->tq) != 0)
96 goto resched;
97 break;
98 }
99 rcu_read_unlock();
100 skb->skb_iif = txp->dev->ifindex;
101
102 if (!skb->tc_from_ingress) {
103 dev_queue_xmit(skb);
104 } else {
105 skb_pull_rcsum(skb, skb->mac_len);
106 netif_receive_skb(skb);
107 }
108 }
109
110 if (__netif_tx_trylock(txq)) {
111 skb = skb_peek(&txp->rq);
112 if (!skb) {
113 txp->tasklet_pending = 0;
114 if (netif_tx_queue_stopped(txq))
115 netif_tx_wake_queue(txq);
116 } else {
117 __netif_tx_unlock(txq);
118 goto resched;
119 }
120 __netif_tx_unlock(txq);
121 } else {
122resched:
123 txp->tasklet_pending = 1;
124 tasklet_schedule(&txp->ifb_tasklet);
125 }
126
127}
128
129static void ifb_stats64(struct net_device *dev,
130 struct rtnl_link_stats64 *stats)
131{
132 struct ifb_dev_private *dp = netdev_priv(dev);
133 struct ifb_q_private *txp = dp->tx_private;
134 unsigned int start;
135 u64 packets, bytes;
136 int i;
137
138 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
139 do {
140 start = u64_stats_fetch_begin_irq(&txp->rsync);
141 packets = txp->rx_packets;
142 bytes = txp->rx_bytes;
143 } while (u64_stats_fetch_retry_irq(&txp->rsync, start));
144 stats->rx_packets += packets;
145 stats->rx_bytes += bytes;
146
147 do {
148 start = u64_stats_fetch_begin_irq(&txp->tsync);
149 packets = txp->tx_packets;
150 bytes = txp->tx_bytes;
151 } while (u64_stats_fetch_retry_irq(&txp->tsync, start));
152 stats->tx_packets += packets;
153 stats->tx_bytes += bytes;
154 }
155 stats->rx_dropped = dev->stats.rx_dropped;
156 stats->tx_dropped = dev->stats.tx_dropped;
157}
158
159static int ifb_dev_init(struct net_device *dev)
160{
161 struct ifb_dev_private *dp = netdev_priv(dev);
162 struct ifb_q_private *txp;
163 int i;
164
165 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
166 if (!txp)
167 return -ENOMEM;
168 dp->tx_private = txp;
169 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
170 txp->txqnum = i;
171 txp->dev = dev;
172 __skb_queue_head_init(&txp->rq);
173 __skb_queue_head_init(&txp->tq);
174 u64_stats_init(&txp->rsync);
175 u64_stats_init(&txp->tsync);
176 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
177 (unsigned long)txp);
178 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
179 }
180 return 0;
181}
182
183static const struct net_device_ops ifb_netdev_ops = {
184 .ndo_open = ifb_open,
185 .ndo_stop = ifb_close,
186 .ndo_get_stats64 = ifb_stats64,
187 .ndo_start_xmit = ifb_xmit,
188 .ndo_validate_addr = eth_validate_addr,
189 .ndo_init = ifb_dev_init,
190};
191
192#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \
193 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \
194 NETIF_F_GSO_ENCAP_ALL | \
195 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
196 NETIF_F_HW_VLAN_STAG_TX)
197
198static void ifb_dev_free(struct net_device *dev)
199{
200 struct ifb_dev_private *dp = netdev_priv(dev);
201 struct ifb_q_private *txp = dp->tx_private;
202 int i;
203
204 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
205 tasklet_kill(&txp->ifb_tasklet);
206 __skb_queue_purge(&txp->rq);
207 __skb_queue_purge(&txp->tq);
208 }
209 kfree(dp->tx_private);
210}
211
212static void ifb_setup(struct net_device *dev)
213{
214 /* Initialize the device structure. */
215 dev->netdev_ops = &ifb_netdev_ops;
216
217 /* Fill in device structure with ethernet-generic values. */
218 ether_setup(dev);
219 dev->tx_queue_len = TX_Q_LIMIT;
220
221 dev->features |= IFB_FEATURES;
222 dev->hw_features |= dev->features;
223 dev->hw_enc_features |= dev->features;
224 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
225 NETIF_F_HW_VLAN_STAG_TX);
226
227 dev->flags |= IFF_NOARP;
228 dev->flags &= ~IFF_MULTICAST;
229 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
230 netif_keep_dst(dev);
231 eth_hw_addr_random(dev);
232 dev->needs_free_netdev = true;
233 dev->priv_destructor = ifb_dev_free;
234
235 dev->min_mtu = 0;
236 dev->max_mtu = 0;
237}
238
239static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
240{
241 struct ifb_dev_private *dp = netdev_priv(dev);
242 struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
243
244 u64_stats_update_begin(&txp->rsync);
245 txp->rx_packets++;
246 txp->rx_bytes += skb->len;
247 u64_stats_update_end(&txp->rsync);
248
249 if (!skb->tc_redirected || !skb->skb_iif) {
250 dev_kfree_skb(skb);
251 dev->stats.rx_dropped++;
252 return NETDEV_TX_OK;
253 }
254
255 if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
256 netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
257
258 __skb_queue_tail(&txp->rq, skb);
259 if (!txp->tasklet_pending) {
260 txp->tasklet_pending = 1;
261 tasklet_schedule(&txp->ifb_tasklet);
262 }
263
264 return NETDEV_TX_OK;
265}
266
267static int ifb_close(struct net_device *dev)
268{
269 netif_tx_stop_all_queues(dev);
270 return 0;
271}
272
273static int ifb_open(struct net_device *dev)
274{
275 netif_tx_start_all_queues(dev);
276 return 0;
277}
278
279static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
280 struct netlink_ext_ack *extack)
281{
282 if (tb[IFLA_ADDRESS]) {
283 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
284 return -EINVAL;
285 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
286 return -EADDRNOTAVAIL;
287 }
288 return 0;
289}
290
291static struct rtnl_link_ops ifb_link_ops __read_mostly = {
292 .kind = "ifb",
293 .priv_size = sizeof(struct ifb_dev_private),
294 .setup = ifb_setup,
295 .validate = ifb_validate,
296};
297
298/* Number of ifb devices to be set up by this module.
299 * Note that these legacy devices have one queue.
300 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
301 */
302static int numifbs = 2;
303module_param(numifbs, int, 0);
304MODULE_PARM_DESC(numifbs, "Number of ifb devices");
305
306static int __init ifb_init_one(int index)
307{
308 struct net_device *dev_ifb;
309 int err;
310
311 dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
312 NET_NAME_UNKNOWN, ifb_setup);
313
314 if (!dev_ifb)
315 return -ENOMEM;
316
317 dev_ifb->rtnl_link_ops = &ifb_link_ops;
318 err = register_netdevice(dev_ifb);
319 if (err < 0)
320 goto err;
321
322 return 0;
323
324err:
325 free_netdev(dev_ifb);
326 return err;
327}
328
329static int __init ifb_init_module(void)
330{
331 int i, err;
332
333 down_write(&pernet_ops_rwsem);
334 rtnl_lock();
335 err = __rtnl_link_register(&ifb_link_ops);
336 if (err < 0)
337 goto out;
338
339 for (i = 0; i < numifbs && !err; i++) {
340 err = ifb_init_one(i);
341 cond_resched();
342 }
343 if (err)
344 __rtnl_link_unregister(&ifb_link_ops);
345
346out:
347 rtnl_unlock();
348 up_write(&pernet_ops_rwsem);
349
350 return err;
351}
352
353static void __exit ifb_cleanup_module(void)
354{
355 rtnl_link_unregister(&ifb_link_ops);
356}
357
358module_init(ifb_init_module);
359module_exit(ifb_cleanup_module);
360MODULE_LICENSE("GPL");
361MODULE_AUTHOR("Jamal Hadi Salim");
362MODULE_ALIAS_RTNL_LINK("ifb");
363