1
2
3
4
5
6
7
8
9
10
11
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/kernel.h>
16#include <linux/errno.h>
17#include <linux/skbuff.h>
18#include <net/pkt_sched.h>
19
20
21
22struct fifo_sched_data
23{
24 u32 limit;
25};
26
27static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
28{
29 struct fifo_sched_data *q = qdisc_priv(sch);
30
31 if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit))
32 return qdisc_enqueue_tail(skb, sch);
33
34 return qdisc_reshape_fail(skb, sch);
35}
36
37static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
38{
39 struct fifo_sched_data *q = qdisc_priv(sch);
40
41 if (likely(skb_queue_len(&sch->q) < q->limit))
42 return qdisc_enqueue_tail(skb, sch);
43
44 return qdisc_reshape_fail(skb, sch);
45}
46
47static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc* sch)
48{
49 struct sk_buff *skb_head;
50 struct fifo_sched_data *q = qdisc_priv(sch);
51
52 if (likely(skb_queue_len(&sch->q) < q->limit))
53 return qdisc_enqueue_tail(skb, sch);
54
55
56 skb_head = qdisc_dequeue_head(sch);
57 sch->bstats.bytes -= qdisc_pkt_len(skb_head);
58 sch->bstats.packets--;
59 sch->qstats.drops++;
60 kfree_skb(skb_head);
61
62 qdisc_enqueue_tail(skb, sch);
63
64 return NET_XMIT_CN;
65}
66
67static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
68{
69 struct fifo_sched_data *q = qdisc_priv(sch);
70
71 if (opt == NULL) {
72 u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
73
74 if (sch->ops == &bfifo_qdisc_ops)
75 limit *= psched_mtu(qdisc_dev(sch));
76
77 q->limit = limit;
78 } else {
79 struct tc_fifo_qopt *ctl = nla_data(opt);
80
81 if (nla_len(opt) < sizeof(*ctl))
82 return -EINVAL;
83
84 q->limit = ctl->limit;
85 }
86
87 return 0;
88}
89
90static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
91{
92 struct fifo_sched_data *q = qdisc_priv(sch);
93 struct tc_fifo_qopt opt = { .limit = q->limit };
94
95 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
96 return skb->len;
97
98nla_put_failure:
99 return -1;
100}
101
102struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
103 .id = "pfifo",
104 .priv_size = sizeof(struct fifo_sched_data),
105 .enqueue = pfifo_enqueue,
106 .dequeue = qdisc_dequeue_head,
107 .peek = qdisc_peek_head,
108 .drop = qdisc_queue_drop,
109 .init = fifo_init,
110 .reset = qdisc_reset_queue,
111 .change = fifo_init,
112 .dump = fifo_dump,
113 .owner = THIS_MODULE,
114};
115EXPORT_SYMBOL(pfifo_qdisc_ops);
116
117struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
118 .id = "bfifo",
119 .priv_size = sizeof(struct fifo_sched_data),
120 .enqueue = bfifo_enqueue,
121 .dequeue = qdisc_dequeue_head,
122 .peek = qdisc_peek_head,
123 .drop = qdisc_queue_drop,
124 .init = fifo_init,
125 .reset = qdisc_reset_queue,
126 .change = fifo_init,
127 .dump = fifo_dump,
128 .owner = THIS_MODULE,
129};
130EXPORT_SYMBOL(bfifo_qdisc_ops);
131
132struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = {
133 .id = "pfifo_head_drop",
134 .priv_size = sizeof(struct fifo_sched_data),
135 .enqueue = pfifo_tail_enqueue,
136 .dequeue = qdisc_dequeue_head,
137 .peek = qdisc_peek_head,
138 .drop = qdisc_queue_drop_head,
139 .init = fifo_init,
140 .reset = qdisc_reset_queue,
141 .change = fifo_init,
142 .dump = fifo_dump,
143 .owner = THIS_MODULE,
144};
145
146
147int fifo_set_limit(struct Qdisc *q, unsigned int limit)
148{
149 struct nlattr *nla;
150 int ret = -ENOMEM;
151
152
153 if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
154 return 0;
155
156 nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
157 if (nla) {
158 nla->nla_type = RTM_NEWQDISC;
159 nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
160 ((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
161
162 ret = q->ops->change(q, nla);
163 kfree(nla);
164 }
165 return ret;
166}
167EXPORT_SYMBOL(fifo_set_limit);
168
169struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
170 unsigned int limit)
171{
172 struct Qdisc *q;
173 int err = -ENOMEM;
174
175 q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
176 ops, TC_H_MAKE(sch->handle, 1));
177 if (q) {
178 err = fifo_set_limit(q, limit);
179 if (err < 0) {
180 qdisc_destroy(q);
181 q = NULL;
182 }
183 }
184
185 return q ? : ERR_PTR(err);
186}
187EXPORT_SYMBOL(fifo_create_dflt);
188
