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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 u32 from = G_TC_FROM(skb->tc_verd);
82
83 skb->tc_verd = 0;
84 skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
85
86 u64_stats_update_begin(&txp->tsync);
87 txp->tx_packets++;
88 txp->tx_bytes += skb->len;
89 u64_stats_update_end(&txp->tsync);
90
91 rcu_read_lock();
92 skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
93 if (!skb->dev) {
94 rcu_read_unlock();
95 dev_kfree_skb(skb);
96 txp->dev->stats.tx_dropped++;
97 if (skb_queue_len(&txp->tq) != 0)
98 goto resched;
99 break;
100 }
101 rcu_read_unlock();
102 skb->skb_iif = txp->dev->ifindex;
103
104 if (from & AT_EGRESS) {
105 dev_queue_xmit(skb);
106 } else if (from & AT_INGRESS) {
107 skb_pull(skb, skb->mac_len);
108 netif_receive_skb(skb);
109 } else
110 BUG();
111 }
112
113 if (__netif_tx_trylock(txq)) {
114 skb = skb_peek(&txp->rq);
115 if (!skb) {
116 txp->tasklet_pending = 0;
117 if (netif_tx_queue_stopped(txq))
118 netif_tx_wake_queue(txq);
119 } else {
120 __netif_tx_unlock(txq);
121 goto resched;
122 }
123 __netif_tx_unlock(txq);
124 } else {
125resched:
126 txp->tasklet_pending = 1;
127 tasklet_schedule(&txp->ifb_tasklet);
128 }
129
130}
131
132static struct rtnl_link_stats64 *ifb_stats64(struct net_device *dev,
133 struct rtnl_link_stats64 *stats)
134{
135 struct ifb_dev_private *dp = netdev_priv(dev);
136 struct ifb_q_private *txp = dp->tx_private;
137 unsigned int start;
138 u64 packets, bytes;
139 int i;
140
141 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
142 do {
143 start = u64_stats_fetch_begin_irq(&txp->rsync);
144 packets = txp->rx_packets;
145 bytes = txp->rx_bytes;
146 } while (u64_stats_fetch_retry_irq(&txp->rsync, start));
147 stats->rx_packets += packets;
148 stats->rx_bytes += bytes;
149
150 do {
151 start = u64_stats_fetch_begin_irq(&txp->tsync);
152 packets = txp->tx_packets;
153 bytes = txp->tx_bytes;
154 } while (u64_stats_fetch_retry_irq(&txp->tsync, start));
155 stats->tx_packets += packets;
156 stats->tx_bytes += bytes;
157 }
158 stats->rx_dropped = dev->stats.rx_dropped;
159 stats->tx_dropped = dev->stats.tx_dropped;
160
161 return stats;
162}
163
164static int ifb_dev_init(struct net_device *dev)
165{
166 struct ifb_dev_private *dp = netdev_priv(dev);
167 struct ifb_q_private *txp;
168 int i;
169
170 txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
171 if (!txp)
172 return -ENOMEM;
173 dp->tx_private = txp;
174 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
175 txp->txqnum = i;
176 txp->dev = dev;
177 __skb_queue_head_init(&txp->rq);
178 __skb_queue_head_init(&txp->tq);
179 u64_stats_init(&txp->rsync);
180 u64_stats_init(&txp->tsync);
181 tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
182 (unsigned long)txp);
183 netif_tx_start_queue(netdev_get_tx_queue(dev, i));
184 }
185 return 0;
186}
187
188static const struct net_device_ops ifb_netdev_ops = {
189 .ndo_open = ifb_open,
190 .ndo_stop = ifb_close,
191 .ndo_get_stats64 = ifb_stats64,
192 .ndo_start_xmit = ifb_xmit,
193 .ndo_validate_addr = eth_validate_addr,
194 .ndo_init = ifb_dev_init,
195};
196
197#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_FRAGLIST | \
198 NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6 | \
199 NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX | \
200 NETIF_F_HW_VLAN_STAG_TX)
201
202static void ifb_dev_free(struct net_device *dev)
203{
204 struct ifb_dev_private *dp = netdev_priv(dev);
205 struct ifb_q_private *txp = dp->tx_private;
206 int i;
207
208 for (i = 0; i < dev->num_tx_queues; i++,txp++) {
209 tasklet_kill(&txp->ifb_tasklet);
210 __skb_queue_purge(&txp->rq);
211 __skb_queue_purge(&txp->tq);
212 }
213 kfree(dp->tx_private);
214 free_netdev(dev);
215}
216
217static void ifb_setup(struct net_device *dev)
218{
219 /* Initialize the device structure. */
220 dev->netdev_ops = &ifb_netdev_ops;
221
222 /* Fill in device structure with ethernet-generic values. */
223 ether_setup(dev);
224 dev->tx_queue_len = TX_Q_LIMIT;
225
226 dev->features |= IFB_FEATURES;
227 dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
228 NETIF_F_HW_VLAN_STAG_TX);
229
230 dev->flags |= IFF_NOARP;
231 dev->flags &= ~IFF_MULTICAST;
232 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
233 netif_keep_dst(dev);
234 eth_hw_addr_random(dev);
235 dev->destructor = ifb_dev_free;
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 u32 from = G_TC_FROM(skb->tc_verd);
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 (!(from & (AT_INGRESS|AT_EGRESS)) || !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{
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 rtnl_lock();
333 err = __rtnl_link_register(&ifb_link_ops);
334 if (err < 0)
335 goto out;
336
337 for (i = 0; i < numifbs && !err; i++) {
338 err = ifb_init_one(i);
339 cond_resched();
340 }
341 if (err)
342 __rtnl_link_unregister(&ifb_link_ops);
343
344out:
345 rtnl_unlock();
346
347 return err;
348}
349
350static void __exit ifb_cleanup_module(void)
351{
352 rtnl_link_unregister(&ifb_link_ops);
353}
354
355module_init(ifb_init_module);
356module_exit(ifb_cleanup_module);
357MODULE_LICENSE("GPL");
358MODULE_AUTHOR("Jamal Hadi Salim");
359MODULE_ALIAS_RTNL_LINK("ifb");
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 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 {
119resched:
120 txp->tasklet_pending = 1;
121 tasklet_schedule(&txp->ifb_tasklet);
122 }
123
124}
125
126static 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
156static 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
180static 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
195static 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
209static 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
236static 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->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
264static int ifb_close(struct net_device *dev)
265{
266 netif_tx_stop_all_queues(dev);
267 return 0;
268}
269
270static int ifb_open(struct net_device *dev)
271{
272 netif_tx_start_all_queues(dev);
273 return 0;
274}
275
276static 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
288static 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 */
299static int numifbs = 2;
300module_param(numifbs, int, 0);
301MODULE_PARM_DESC(numifbs, "Number of ifb devices");
302
303static 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
321err:
322 free_netdev(dev_ifb);
323 return err;
324}
325
326static 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
343out:
344 rtnl_unlock();
345 up_write(&pernet_ops_rwsem);
346
347 return err;
348}
349
350static void __exit ifb_cleanup_module(void)
351{
352 rtnl_link_unregister(&ifb_link_ops);
353}
354
355module_init(ifb_init_module);
356module_exit(ifb_cleanup_module);
357MODULE_LICENSE("GPL");
358MODULE_AUTHOR("Jamal Hadi Salim");
359MODULE_ALIAS_RTNL_LINK("ifb");