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1da177e4 LT |
1 | /* |
2 | * net/sched/sch_red.c Random Early Detection 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 | * Changes: | |
dba051f3 | 12 | * J Hadi Salim 980914: computation fixes |
1da177e4 | 13 | * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly. |
dba051f3 | 14 | * J Hadi Salim 980816: ECN support |
1da177e4 LT |
15 | */ |
16 | ||
17 | #include <linux/config.h> | |
18 | #include <linux/module.h> | |
1da177e4 LT |
19 | #include <linux/types.h> |
20 | #include <linux/kernel.h> | |
1da177e4 | 21 | #include <linux/netdevice.h> |
1da177e4 | 22 | #include <linux/skbuff.h> |
1da177e4 LT |
23 | #include <net/pkt_sched.h> |
24 | #include <net/inet_ecn.h> | |
6b31b28a | 25 | #include <net/red.h> |
1da177e4 LT |
26 | |
27 | ||
6b31b28a | 28 | /* Parameters, settable by user: |
1da177e4 LT |
29 | ----------------------------- |
30 | ||
31 | limit - bytes (must be > qth_max + burst) | |
32 | ||
33 | Hard limit on queue length, should be chosen >qth_max | |
34 | to allow packet bursts. This parameter does not | |
35 | affect the algorithms behaviour and can be chosen | |
36 | arbitrarily high (well, less than ram size) | |
37 | Really, this limit will never be reached | |
38 | if RED works correctly. | |
1da177e4 LT |
39 | */ |
40 | ||
41 | struct red_sched_data | |
42 | { | |
6b31b28a TG |
43 | u32 limit; /* HARD maximal queue length */ |
44 | unsigned char flags; | |
45 | struct red_parms parms; | |
46 | struct red_stats stats; | |
1da177e4 LT |
47 | }; |
48 | ||
6b31b28a | 49 | static inline int red_use_ecn(struct red_sched_data *q) |
1da177e4 | 50 | { |
6b31b28a | 51 | return q->flags & TC_RED_ECN; |
1da177e4 LT |
52 | } |
53 | ||
dba051f3 | 54 | static int red_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
1da177e4 LT |
55 | { |
56 | struct red_sched_data *q = qdisc_priv(sch); | |
57 | ||
6b31b28a | 58 | q->parms.qavg = red_calc_qavg(&q->parms, sch->qstats.backlog); |
1da177e4 | 59 | |
6b31b28a TG |
60 | if (red_is_idling(&q->parms)) |
61 | red_end_of_idle_period(&q->parms); | |
1da177e4 | 62 | |
6b31b28a TG |
63 | switch (red_action(&q->parms, q->parms.qavg)) { |
64 | case RED_DONT_MARK: | |
65 | break; | |
1da177e4 | 66 | |
6b31b28a TG |
67 | case RED_PROB_MARK: |
68 | sch->qstats.overlimits++; | |
69 | if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
70 | q->stats.prob_drop++; | |
71 | goto congestion_drop; | |
72 | } | |
1da177e4 | 73 | |
6b31b28a TG |
74 | q->stats.prob_mark++; |
75 | break; | |
76 | ||
77 | case RED_HARD_MARK: | |
78 | sch->qstats.overlimits++; | |
79 | if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { | |
80 | q->stats.forced_drop++; | |
81 | goto congestion_drop; | |
82 | } | |
83 | ||
84 | q->stats.forced_mark++; | |
85 | break; | |
1da177e4 LT |
86 | } |
87 | ||
9e178ff2 TG |
88 | if (sch->qstats.backlog + skb->len <= q->limit) |
89 | return qdisc_enqueue_tail(skb, sch); | |
1da177e4 | 90 | |
6b31b28a | 91 | q->stats.pdrop++; |
9e178ff2 | 92 | return qdisc_drop(skb, sch); |
6b31b28a TG |
93 | |
94 | congestion_drop: | |
9e178ff2 | 95 | qdisc_drop(skb, sch); |
1da177e4 LT |
96 | return NET_XMIT_CN; |
97 | } | |
98 | ||
dba051f3 | 99 | static int red_requeue(struct sk_buff *skb, struct Qdisc* sch) |
1da177e4 LT |
100 | { |
101 | struct red_sched_data *q = qdisc_priv(sch); | |
102 | ||
6b31b28a TG |
103 | if (red_is_idling(&q->parms)) |
104 | red_end_of_idle_period(&q->parms); | |
1da177e4 | 105 | |
9e178ff2 | 106 | return qdisc_requeue(skb, sch); |
1da177e4 LT |
107 | } |
108 | ||
dba051f3 | 109 | static struct sk_buff * red_dequeue(struct Qdisc* sch) |
1da177e4 LT |
110 | { |
111 | struct sk_buff *skb; | |
112 | struct red_sched_data *q = qdisc_priv(sch); | |
113 | ||
9e178ff2 | 114 | skb = qdisc_dequeue_head(sch); |
6b31b28a | 115 | |
6a1b63d4 | 116 | if (skb == NULL && !red_is_idling(&q->parms)) |
9e178ff2 TG |
117 | red_start_of_idle_period(&q->parms); |
118 | ||
119 | return skb; | |
1da177e4 LT |
120 | } |
121 | ||
122 | static unsigned int red_drop(struct Qdisc* sch) | |
123 | { | |
124 | struct sk_buff *skb; | |
125 | struct red_sched_data *q = qdisc_priv(sch); | |
126 | ||
9e178ff2 | 127 | skb = qdisc_dequeue_tail(sch); |
1da177e4 LT |
128 | if (skb) { |
129 | unsigned int len = skb->len; | |
6b31b28a | 130 | q->stats.other++; |
9e178ff2 | 131 | qdisc_drop(skb, sch); |
1da177e4 LT |
132 | return len; |
133 | } | |
6b31b28a | 134 | |
6a1b63d4 TG |
135 | if (!red_is_idling(&q->parms)) |
136 | red_start_of_idle_period(&q->parms); | |
137 | ||
1da177e4 LT |
138 | return 0; |
139 | } | |
140 | ||
141 | static void red_reset(struct Qdisc* sch) | |
142 | { | |
143 | struct red_sched_data *q = qdisc_priv(sch); | |
144 | ||
9e178ff2 | 145 | qdisc_reset_queue(sch); |
6b31b28a | 146 | red_restart(&q->parms); |
1da177e4 LT |
147 | } |
148 | ||
149 | static int red_change(struct Qdisc *sch, struct rtattr *opt) | |
150 | { | |
151 | struct red_sched_data *q = qdisc_priv(sch); | |
dba051f3 | 152 | struct rtattr *tb[TCA_RED_MAX]; |
1da177e4 LT |
153 | struct tc_red_qopt *ctl; |
154 | ||
dba051f3 TG |
155 | if (opt == NULL || rtattr_parse_nested(tb, TCA_RED_MAX, opt)) |
156 | return -EINVAL; | |
157 | ||
158 | if (tb[TCA_RED_PARMS-1] == NULL || | |
1da177e4 | 159 | RTA_PAYLOAD(tb[TCA_RED_PARMS-1]) < sizeof(*ctl) || |
dba051f3 TG |
160 | tb[TCA_RED_STAB-1] == NULL || |
161 | RTA_PAYLOAD(tb[TCA_RED_STAB-1]) < RED_STAB_SIZE) | |
1da177e4 LT |
162 | return -EINVAL; |
163 | ||
164 | ctl = RTA_DATA(tb[TCA_RED_PARMS-1]); | |
165 | ||
166 | sch_tree_lock(sch); | |
167 | q->flags = ctl->flags; | |
1da177e4 | 168 | q->limit = ctl->limit; |
1da177e4 | 169 | |
6b31b28a TG |
170 | red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog, |
171 | ctl->Plog, ctl->Scell_log, | |
172 | RTA_DATA(tb[TCA_RED_STAB-1])); | |
173 | ||
b03efcfb | 174 | if (skb_queue_empty(&sch->q)) |
6b31b28a | 175 | red_end_of_idle_period(&q->parms); |
dba051f3 | 176 | |
1da177e4 LT |
177 | sch_tree_unlock(sch); |
178 | return 0; | |
179 | } | |
180 | ||
181 | static int red_init(struct Qdisc* sch, struct rtattr *opt) | |
182 | { | |
183 | return red_change(sch, opt); | |
184 | } | |
185 | ||
186 | static int red_dump(struct Qdisc *sch, struct sk_buff *skb) | |
187 | { | |
188 | struct red_sched_data *q = qdisc_priv(sch); | |
dba051f3 | 189 | struct rtattr *opts = NULL; |
6b31b28a TG |
190 | struct tc_red_qopt opt = { |
191 | .limit = q->limit, | |
192 | .flags = q->flags, | |
193 | .qth_min = q->parms.qth_min >> q->parms.Wlog, | |
194 | .qth_max = q->parms.qth_max >> q->parms.Wlog, | |
195 | .Wlog = q->parms.Wlog, | |
196 | .Plog = q->parms.Plog, | |
197 | .Scell_log = q->parms.Scell_log, | |
198 | }; | |
1da177e4 | 199 | |
dba051f3 | 200 | opts = RTA_NEST(skb, TCA_OPTIONS); |
1da177e4 | 201 | RTA_PUT(skb, TCA_RED_PARMS, sizeof(opt), &opt); |
dba051f3 | 202 | return RTA_NEST_END(skb, opts); |
1da177e4 LT |
203 | |
204 | rtattr_failure: | |
dba051f3 | 205 | return RTA_NEST_CANCEL(skb, opts); |
1da177e4 LT |
206 | } |
207 | ||
208 | static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
209 | { | |
210 | struct red_sched_data *q = qdisc_priv(sch); | |
6b31b28a TG |
211 | struct tc_red_xstats st = { |
212 | .early = q->stats.prob_drop + q->stats.forced_drop, | |
213 | .pdrop = q->stats.pdrop, | |
214 | .other = q->stats.other, | |
215 | .marked = q->stats.prob_mark + q->stats.forced_mark, | |
216 | }; | |
217 | ||
218 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
1da177e4 LT |
219 | } |
220 | ||
221 | static struct Qdisc_ops red_qdisc_ops = { | |
1da177e4 LT |
222 | .id = "red", |
223 | .priv_size = sizeof(struct red_sched_data), | |
224 | .enqueue = red_enqueue, | |
225 | .dequeue = red_dequeue, | |
226 | .requeue = red_requeue, | |
227 | .drop = red_drop, | |
228 | .init = red_init, | |
229 | .reset = red_reset, | |
230 | .change = red_change, | |
231 | .dump = red_dump, | |
232 | .dump_stats = red_dump_stats, | |
233 | .owner = THIS_MODULE, | |
234 | }; | |
235 | ||
236 | static int __init red_module_init(void) | |
237 | { | |
238 | return register_qdisc(&red_qdisc_ops); | |
239 | } | |
dba051f3 TG |
240 | |
241 | static void __exit red_module_exit(void) | |
1da177e4 LT |
242 | { |
243 | unregister_qdisc(&red_qdisc_ops); | |
244 | } | |
dba051f3 | 245 | |
1da177e4 LT |
246 | module_init(red_module_init) |
247 | module_exit(red_module_exit) | |
dba051f3 | 248 | |
1da177e4 | 249 | MODULE_LICENSE("GPL"); |