File: /usr/src/linux/net/sched/sch_fifo.c
1 /*
2 * net/sched/sch_fifo.c The simplest FIFO queue.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/config.h>
13 #include <asm/uaccess.h>
14 #include <asm/system.h>
15 #include <asm/bitops.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/mm.h>
21 #include <linux/socket.h>
22 #include <linux/sockios.h>
23 #include <linux/in.h>
24 #include <linux/errno.h>
25 #include <linux/interrupt.h>
26 #include <linux/if_ether.h>
27 #include <linux/inet.h>
28 #include <linux/netdevice.h>
29 #include <linux/etherdevice.h>
30 #include <linux/notifier.h>
31 #include <net/ip.h>
32 #include <net/route.h>
33 #include <linux/skbuff.h>
34 #include <net/sock.h>
35 #include <net/pkt_sched.h>
36
37 /* 1 band FIFO pseudo-"scheduler" */
38
39 struct fifo_sched_data
40 {
41 unsigned limit;
42 };
43
44 static int
45 bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
46 {
47 struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
48
49 if (sch->stats.backlog <= q->limit) {
50 __skb_queue_tail(&sch->q, skb);
51 sch->stats.backlog += skb->len;
52 sch->stats.bytes += skb->len;
53 sch->stats.packets++;
54 return 0;
55 }
56 sch->stats.drops++;
57 #ifdef CONFIG_NET_CLS_POLICE
58 if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
59 #endif
60 kfree_skb(skb);
61 return NET_XMIT_DROP;
62 }
63
64 static int
65 bfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
66 {
67 __skb_queue_head(&sch->q, skb);
68 sch->stats.backlog += skb->len;
69 return 0;
70 }
71
72 static struct sk_buff *
73 bfifo_dequeue(struct Qdisc* sch)
74 {
75 struct sk_buff *skb;
76
77 skb = __skb_dequeue(&sch->q);
78 if (skb)
79 sch->stats.backlog -= skb->len;
80 return skb;
81 }
82
83 static int
84 fifo_drop(struct Qdisc* sch)
85 {
86 struct sk_buff *skb;
87
88 skb = __skb_dequeue_tail(&sch->q);
89 if (skb) {
90 sch->stats.backlog -= skb->len;
91 kfree_skb(skb);
92 return 1;
93 }
94 return 0;
95 }
96
97 static void
98 fifo_reset(struct Qdisc* sch)
99 {
100 skb_queue_purge(&sch->q);
101 sch->stats.backlog = 0;
102 }
103
104 static int
105 pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
106 {
107 struct fifo_sched_data *q = (struct fifo_sched_data *)sch->data;
108
109 if (sch->q.qlen <= q->limit) {
110 __skb_queue_tail(&sch->q, skb);
111 sch->stats.bytes += skb->len;
112 sch->stats.packets++;
113 return 0;
114 }
115 sch->stats.drops++;
116 #ifdef CONFIG_NET_CLS_POLICE
117 if (sch->reshape_fail==NULL || sch->reshape_fail(skb, sch))
118 #endif
119 kfree_skb(skb);
120 return NET_XMIT_DROP;
121 }
122
123 static int
124 pfifo_requeue(struct sk_buff *skb, struct Qdisc* sch)
125 {
126 __skb_queue_head(&sch->q, skb);
127 return 0;
128 }
129
130
131 static struct sk_buff *
132 pfifo_dequeue(struct Qdisc* sch)
133 {
134 return __skb_dequeue(&sch->q);
135 }
136
137 static int fifo_init(struct Qdisc *sch, struct rtattr *opt)
138 {
139 struct fifo_sched_data *q = (void*)sch->data;
140
141 if (opt == NULL) {
142 if (sch->ops == &bfifo_qdisc_ops)
143 q->limit = sch->dev->tx_queue_len*sch->dev->mtu;
144 else
145 q->limit = sch->dev->tx_queue_len;
146 } else {
147 struct tc_fifo_qopt *ctl = RTA_DATA(opt);
148 if (opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
149 return -EINVAL;
150 q->limit = ctl->limit;
151 }
152 return 0;
153 }
154
155 #ifdef CONFIG_RTNETLINK
156 static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
157 {
158 struct fifo_sched_data *q = (void*)sch->data;
159 unsigned char *b = skb->tail;
160 struct tc_fifo_qopt opt;
161
162 opt.limit = q->limit;
163 RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
164
165 return skb->len;
166
167 rtattr_failure:
168 skb_trim(skb, b - skb->data);
169 return -1;
170 }
171 #endif
172
173 struct Qdisc_ops pfifo_qdisc_ops =
174 {
175 NULL,
176 NULL,
177 "pfifo",
178 sizeof(struct fifo_sched_data),
179
180 pfifo_enqueue,
181 pfifo_dequeue,
182 pfifo_requeue,
183 fifo_drop,
184
185 fifo_init,
186 fifo_reset,
187 NULL,
188 fifo_init,
189
190 #ifdef CONFIG_RTNETLINK
191 fifo_dump,
192 #endif
193 };
194
195 struct Qdisc_ops bfifo_qdisc_ops =
196 {
197 NULL,
198 NULL,
199 "bfifo",
200 sizeof(struct fifo_sched_data),
201
202 bfifo_enqueue,
203 bfifo_dequeue,
204 bfifo_requeue,
205 fifo_drop,
206
207 fifo_init,
208 fifo_reset,
209 NULL,
210 fifo_init,
211 #ifdef CONFIG_RTNETLINK
212 fifo_dump,
213 #endif
214 };
215