summaryrefslogtreecommitdiffstats
path: root/drivers/net/ifb.c
blob: 819945e3b33095bfde56e38a205dcd1f1e1c66bd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
/* drivers/net/ifb.c:

	The purpose of this driver is to provide a device that allows
	for sharing of resources:

	1) qdiscs/policies that are per device as opposed to system wide.
	ifb allows for a device which can be redirected to thus providing
	an impression of sharing.

	2) Allows for queueing incoming traffic for shaping instead of
	dropping.

	The original concept is based on what is known as the IMQ
	driver initially written by Martin Devera, later rewritten
	by Patrick McHardy and then maintained by Andre Correa.

	You need the tc action  mirror or redirect to feed this device
       	packets.

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version
	2 of the License, or (at your option) any later version.

  	Authors:	Jamal Hadi Salim (2005)

*/


#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/list.h>
#include <net/pkt_sched.h>

#define TX_TIMEOUT  (2*HZ)

#define TX_Q_LIMIT    32
struct ifb_private {
	struct list_head	list;
	struct net_device	*dev;
	struct net_device_stats stats;
	struct tasklet_struct   ifb_tasklet;
	int     tasklet_pending;
	/* mostly debug stats leave in for now */
	unsigned long   st_task_enter; /* tasklet entered */
	unsigned long   st_txq_refl_try; /* transmit queue refill attempt */
	unsigned long   st_rxq_enter; /* receive queue entered */
	unsigned long   st_rx2tx_tran; /* receive to trasmit transfers */
	unsigned long   st_rxq_notenter; /*receiveQ not entered, resched */
	unsigned long   st_rx_frm_egr; /* received from egress path */
	unsigned long   st_rx_frm_ing; /* received from ingress path */
	unsigned long   st_rxq_check;
	unsigned long   st_rxq_rsch;
	struct sk_buff_head     rq;
	struct sk_buff_head     tq;
};

static int numifbs = 2;

static void ri_tasklet(unsigned long dev);
static int ifb_xmit(struct sk_buff *skb, struct net_device *dev);
static struct net_device_stats *ifb_get_stats(struct net_device *dev);
static int ifb_open(struct net_device *dev);
static int ifb_close(struct net_device *dev);

static void ri_tasklet(unsigned long dev)
{

	struct net_device *_dev = (struct net_device *)dev;
	struct ifb_private *dp = netdev_priv(_dev);
	struct net_device_stats *stats = &dp->stats;
	struct sk_buff *skb;

	dp->st_task_enter++;
	if ((skb = skb_peek(&dp->tq)) == NULL) {
		dp->st_txq_refl_try++;
		if (netif_tx_trylock(_dev)) {
			dp->st_rxq_enter++;
			while ((skb = skb_dequeue(&dp->rq)) != NULL) {
				skb_queue_tail(&dp->tq, skb);
				dp->st_rx2tx_tran++;
			}
			netif_tx_unlock(_dev);
		} else {
			/* reschedule */
			dp->st_rxq_notenter++;
			goto resched;
		}
	}

	while ((skb = skb_dequeue(&dp->tq)) != NULL) {
		u32 from = G_TC_FROM(skb->tc_verd);

		skb->tc_verd = 0;
		skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
		stats->tx_packets++;
		stats->tx_bytes +=skb->len;

		skb->dev = __dev_get_by_index(skb->iif);
		if (!skb->dev) {
			dev_kfree_skb(skb);
			stats->tx_dropped++;
			break;
		}
		skb->iif = _dev->ifindex;

		if (from & AT_EGRESS) {
			dp->st_rx_frm_egr++;
			dev_queue_xmit(skb);
		} else if (from & AT_INGRESS) {
			dp->st_rx_frm_ing++;
			skb_pull(skb, skb->dev->hard_header_len);
			netif_rx(skb);
		} else
			BUG();
	}

	if (netif_tx_trylock(_dev)) {
		dp->st_rxq_check++;
		if ((skb = skb_peek(&dp->rq)) == NULL) {
			dp->tasklet_pending = 0;
			if (netif_queue_stopped(_dev))
				netif_wake_queue(_dev);
		} else {
			dp->st_rxq_rsch++;
			netif_tx_unlock(_dev);
			goto resched;
		}
		netif_tx_unlock(_dev);
	} else {
resched:
		dp->tasklet_pending = 1;
		tasklet_schedule(&dp->ifb_tasklet);
	}

}

static void __init ifb_setup(struct net_device *dev)
{
	/* Initialize the device structure. */
	dev->get_stats = ifb_get_stats;
	dev->hard_start_xmit = ifb_xmit;
	dev->open = &ifb_open;
	dev->stop = &ifb_close;

	/* Fill in device structure with ethernet-generic values. */
	ether_setup(dev);
	dev->tx_queue_len = TX_Q_LIMIT;
	dev->change_mtu = NULL;
	dev->flags |= IFF_NOARP;
	dev->flags &= ~IFF_MULTICAST;
	SET_MODULE_OWNER(dev);
	random_ether_addr(dev->dev_addr);
}

static int ifb_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct ifb_private *dp = netdev_priv(dev);
	struct net_device_stats *stats = &dp->stats;
	int ret = 0;
	u32 from = G_TC_FROM(skb->tc_verd);

	stats->rx_packets++;
	stats->rx_bytes+=skb->len;

	if (!(from & (AT_INGRESS|AT_EGRESS)) || !skb->iif) {
		dev_kfree_skb(skb);
		stats->rx_dropped++;
		return ret;
	}

	if (skb_queue_len(&dp->rq) >= dev->tx_queue_len) {
		netif_stop_queue(dev);
	}

	dev->trans_start = jiffies;
	skb_queue_tail(&dp->rq, skb);
	if (!dp->tasklet_pending) {
		dp->tasklet_pending = 1;
		tasklet_schedule(&dp->ifb_tasklet);
	}

	return ret;
}

static struct net_device_stats *ifb_get_stats(struct net_device *dev)
{
	struct ifb_private *dp = netdev_priv(dev);
	struct net_device_stats *stats = &dp->stats;

	pr_debug("tasklets stats %ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld:%ld \n",
		dp->st_task_enter, dp->st_txq_refl_try, dp->st_rxq_enter,
		dp->st_rx2tx_tran, dp->st_rxq_notenter, dp->st_rx_frm_egr,
		dp->st_rx_frm_ing, dp->st_rxq_check, dp->st_rxq_rsch);

	return stats;
}

static LIST_HEAD(ifbs);

/* Number of ifb devices to be set up by this module. */
module_param(numifbs, int, 0);
MODULE_PARM_DESC(numifbs, "Number of ifb devices");

static int ifb_close(struct net_device *dev)
{
	struct ifb_private *dp = netdev_priv(dev);

	tasklet_kill(&dp->ifb_tasklet);
	netif_stop_queue(dev);
	skb_queue_purge(&dp->rq);
	skb_queue_purge(&dp->tq);
	return 0;
}

static int ifb_open(struct net_device *dev)
{
	struct ifb_private *dp = netdev_priv(dev);

	tasklet_init(&dp->ifb_tasklet, ri_tasklet, (unsigned long)dev);
	skb_queue_head_init(&dp->rq);
	skb_queue_head_init(&dp->tq);
	netif_start_queue(dev);

	return 0;
}

static int __init ifb_init_one(int index)
{
	struct net_device *dev_ifb;
	struct ifb_private *priv;
	int err;

	dev_ifb = alloc_netdev(sizeof(struct ifb_private),
				 "ifb%d", ifb_setup);

	if (!dev_ifb)
		return -ENOMEM;

	if ((err = register_netdev(dev_ifb))) {
		free_netdev(dev_ifb);
		dev_ifb = NULL;
	} else {
		priv = netdev_priv(dev_ifb);
		priv->dev = dev_ifb;
		list_add_tail(&priv->list, &ifbs);
	}

	return err;
}

static void ifb_free_one(struct net_device *dev)
{
	struct ifb_private *priv = netdev_priv(dev);

	list_del(&priv->list);
	unregister_netdev(dev);
	free_netdev(dev);
}

static int __init ifb_init_module(void)
{
	struct ifb_private *priv, *next;
	int i, err = 0;

	for (i = 0; i < numifbs && !err; i++)
		err = ifb_init_one(i);
	if (err) {
		list_for_each_entry_safe(priv, next, &ifbs, list)
			ifb_free_one(priv->dev);
	}

	return err;
}

static void __exit ifb_cleanup_module(void)
{
	struct ifb_private *priv, *next;

	list_for_each_entry_safe(priv, next, &ifbs, list)
		ifb_free_one(priv->dev);
}

module_init(ifb_init_module);
module_exit(ifb_cleanup_module);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamal Hadi Salim");