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32c7eec2 | 1 | // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause |
76e3cc12 ED |
2 | /* |
3 | * Codel - The Controlled-Delay Active Queue Management algorithm | |
4 | * | |
5 | * Copyright (C) 2011-2012 Kathleen Nichols <nichols@pollere.com> | |
6 | * Copyright (C) 2011-2012 Van Jacobson <van@pollere.net> | |
7 | * | |
8 | * Implemented on linux by : | |
9 | * Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net> | |
80ba92fa | 10 | * Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com> |
76e3cc12 ED |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/types.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/skbuff.h> | |
ce5b4b97 | 19 | #include <linux/prefetch.h> |
76e3cc12 ED |
20 | #include <net/pkt_sched.h> |
21 | #include <net/codel.h> | |
d068ca2a MK |
22 | #include <net/codel_impl.h> |
23 | #include <net/codel_qdisc.h> | |
76e3cc12 ED |
24 | |
25 | ||
26 | #define DEFAULT_CODEL_LIMIT 1000 | |
27 | ||
28 | struct codel_sched_data { | |
29 | struct codel_params params; | |
30 | struct codel_vars vars; | |
31 | struct codel_stats stats; | |
32 | u32 drop_overlimit; | |
33 | }; | |
34 | ||
35 | /* This is the specific function called from codel_dequeue() | |
36 | * to dequeue a packet from queue. Note: backlog is handled in | |
37 | * codel, we dont need to reduce it here. | |
38 | */ | |
79bdc4c8 | 39 | static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx) |
76e3cc12 | 40 | { |
79bdc4c8 | 41 | struct Qdisc *sch = ctx; |
ed760cb8 | 42 | struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); |
76e3cc12 | 43 | |
051c7b39 | 44 | if (skb) { |
79bdc4c8 | 45 | sch->qstats.backlog -= qdisc_pkt_len(skb); |
051c7b39 JJB |
46 | prefetch(&skb->end); /* we'll need skb_shinfo() */ |
47 | } | |
76e3cc12 ED |
48 | return skb; |
49 | } | |
50 | ||
79bdc4c8 MK |
51 | static void drop_func(struct sk_buff *skb, void *ctx) |
52 | { | |
53 | struct Qdisc *sch = ctx; | |
54 | ||
520ac30f ED |
55 | kfree_skb(skb); |
56 | qdisc_qstats_drop(sch); | |
79bdc4c8 MK |
57 | } |
58 | ||
76e3cc12 ED |
59 | static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch) |
60 | { | |
61 | struct codel_sched_data *q = qdisc_priv(sch); | |
62 | struct sk_buff *skb; | |
63 | ||
79bdc4c8 MK |
64 | skb = codel_dequeue(sch, &sch->qstats.backlog, &q->params, &q->vars, |
65 | &q->stats, qdisc_pkt_len, codel_get_enqueue_time, | |
66 | drop_func, dequeue_func); | |
865ec552 | 67 | |
2ccccf5f | 68 | /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0, |
76e3cc12 ED |
69 | * or HTB crashes. Defer it for next round. |
70 | */ | |
71 | if (q->stats.drop_count && sch->q.qlen) { | |
2ccccf5f | 72 | qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len); |
76e3cc12 | 73 | q->stats.drop_count = 0; |
2ccccf5f | 74 | q->stats.drop_len = 0; |
76e3cc12 ED |
75 | } |
76 | if (skb) | |
77 | qdisc_bstats_update(sch, skb); | |
78 | return skb; | |
79 | } | |
80 | ||
520ac30f ED |
81 | static int codel_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
82 | struct sk_buff **to_free) | |
76e3cc12 ED |
83 | { |
84 | struct codel_sched_data *q; | |
85 | ||
86 | if (likely(qdisc_qlen(sch) < sch->limit)) { | |
87 | codel_set_enqueue_time(skb); | |
88 | return qdisc_enqueue_tail(skb, sch); | |
89 | } | |
90 | q = qdisc_priv(sch); | |
91 | q->drop_overlimit++; | |
520ac30f | 92 | return qdisc_drop(skb, sch, to_free); |
76e3cc12 ED |
93 | } |
94 | ||
95 | static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = { | |
96 | [TCA_CODEL_TARGET] = { .type = NLA_U32 }, | |
97 | [TCA_CODEL_LIMIT] = { .type = NLA_U32 }, | |
98 | [TCA_CODEL_INTERVAL] = { .type = NLA_U32 }, | |
99 | [TCA_CODEL_ECN] = { .type = NLA_U32 }, | |
80ba92fa | 100 | [TCA_CODEL_CE_THRESHOLD]= { .type = NLA_U32 }, |
76e3cc12 ED |
101 | }; |
102 | ||
2030721c AA |
103 | static int codel_change(struct Qdisc *sch, struct nlattr *opt, |
104 | struct netlink_ext_ack *extack) | |
76e3cc12 ED |
105 | { |
106 | struct codel_sched_data *q = qdisc_priv(sch); | |
107 | struct nlattr *tb[TCA_CODEL_MAX + 1]; | |
2ccccf5f | 108 | unsigned int qlen, dropped = 0; |
76e3cc12 ED |
109 | int err; |
110 | ||
8cb08174 JB |
111 | err = nla_parse_nested_deprecated(tb, TCA_CODEL_MAX, opt, |
112 | codel_policy, NULL); | |
76e3cc12 ED |
113 | if (err < 0) |
114 | return err; | |
115 | ||
116 | sch_tree_lock(sch); | |
117 | ||
118 | if (tb[TCA_CODEL_TARGET]) { | |
119 | u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]); | |
120 | ||
121 | q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT; | |
122 | } | |
123 | ||
80ba92fa ED |
124 | if (tb[TCA_CODEL_CE_THRESHOLD]) { |
125 | u64 val = nla_get_u32(tb[TCA_CODEL_CE_THRESHOLD]); | |
126 | ||
127 | q->params.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT; | |
128 | } | |
129 | ||
76e3cc12 ED |
130 | if (tb[TCA_CODEL_INTERVAL]) { |
131 | u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]); | |
132 | ||
133 | q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT; | |
134 | } | |
135 | ||
136 | if (tb[TCA_CODEL_LIMIT]) | |
137 | sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]); | |
138 | ||
139 | if (tb[TCA_CODEL_ECN]) | |
140 | q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]); | |
141 | ||
142 | qlen = sch->q.qlen; | |
143 | while (sch->q.qlen > sch->limit) { | |
ed760cb8 | 144 | struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); |
76e3cc12 | 145 | |
2ccccf5f | 146 | dropped += qdisc_pkt_len(skb); |
25331d6c | 147 | qdisc_qstats_backlog_dec(sch, skb); |
b3d7e2b2 | 148 | rtnl_qdisc_drop(skb, sch); |
76e3cc12 | 149 | } |
2ccccf5f | 150 | qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); |
76e3cc12 ED |
151 | |
152 | sch_tree_unlock(sch); | |
153 | return 0; | |
154 | } | |
155 | ||
e63d7dfd AA |
156 | static int codel_init(struct Qdisc *sch, struct nlattr *opt, |
157 | struct netlink_ext_ack *extack) | |
76e3cc12 ED |
158 | { |
159 | struct codel_sched_data *q = qdisc_priv(sch); | |
160 | ||
161 | sch->limit = DEFAULT_CODEL_LIMIT; | |
162 | ||
79bdc4c8 | 163 | codel_params_init(&q->params); |
76e3cc12 ED |
164 | codel_vars_init(&q->vars); |
165 | codel_stats_init(&q->stats); | |
79bdc4c8 | 166 | q->params.mtu = psched_mtu(qdisc_dev(sch)); |
76e3cc12 ED |
167 | |
168 | if (opt) { | |
2030721c | 169 | int err = codel_change(sch, opt, extack); |
76e3cc12 ED |
170 | |
171 | if (err) | |
172 | return err; | |
173 | } | |
174 | ||
175 | if (sch->limit >= 1) | |
176 | sch->flags |= TCQ_F_CAN_BYPASS; | |
177 | else | |
178 | sch->flags &= ~TCQ_F_CAN_BYPASS; | |
179 | ||
180 | return 0; | |
181 | } | |
182 | ||
183 | static int codel_dump(struct Qdisc *sch, struct sk_buff *skb) | |
184 | { | |
185 | struct codel_sched_data *q = qdisc_priv(sch); | |
186 | struct nlattr *opts; | |
187 | ||
ae0be8de | 188 | opts = nla_nest_start_noflag(skb, TCA_OPTIONS); |
76e3cc12 ED |
189 | if (opts == NULL) |
190 | goto nla_put_failure; | |
191 | ||
192 | if (nla_put_u32(skb, TCA_CODEL_TARGET, | |
193 | codel_time_to_us(q->params.target)) || | |
194 | nla_put_u32(skb, TCA_CODEL_LIMIT, | |
195 | sch->limit) || | |
196 | nla_put_u32(skb, TCA_CODEL_INTERVAL, | |
197 | codel_time_to_us(q->params.interval)) || | |
198 | nla_put_u32(skb, TCA_CODEL_ECN, | |
199 | q->params.ecn)) | |
200 | goto nla_put_failure; | |
80ba92fa ED |
201 | if (q->params.ce_threshold != CODEL_DISABLED_THRESHOLD && |
202 | nla_put_u32(skb, TCA_CODEL_CE_THRESHOLD, | |
203 | codel_time_to_us(q->params.ce_threshold))) | |
204 | goto nla_put_failure; | |
76e3cc12 ED |
205 | return nla_nest_end(skb, opts); |
206 | ||
207 | nla_put_failure: | |
208 | nla_nest_cancel(skb, opts); | |
209 | return -1; | |
210 | } | |
211 | ||
212 | static int codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
213 | { | |
214 | const struct codel_sched_data *q = qdisc_priv(sch); | |
215 | struct tc_codel_xstats st = { | |
216 | .maxpacket = q->stats.maxpacket, | |
217 | .count = q->vars.count, | |
218 | .lastcount = q->vars.lastcount, | |
219 | .drop_overlimit = q->drop_overlimit, | |
220 | .ldelay = codel_time_to_us(q->vars.ldelay), | |
221 | .dropping = q->vars.dropping, | |
222 | .ecn_mark = q->stats.ecn_mark, | |
80ba92fa | 223 | .ce_mark = q->stats.ce_mark, |
76e3cc12 ED |
224 | }; |
225 | ||
226 | if (q->vars.dropping) { | |
227 | codel_tdiff_t delta = q->vars.drop_next - codel_get_time(); | |
228 | ||
229 | if (delta >= 0) | |
230 | st.drop_next = codel_time_to_us(delta); | |
231 | else | |
232 | st.drop_next = -codel_time_to_us(-delta); | |
233 | } | |
234 | ||
235 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
236 | } | |
237 | ||
238 | static void codel_reset(struct Qdisc *sch) | |
239 | { | |
240 | struct codel_sched_data *q = qdisc_priv(sch); | |
241 | ||
242 | qdisc_reset_queue(sch); | |
243 | codel_vars_init(&q->vars); | |
244 | } | |
245 | ||
246 | static struct Qdisc_ops codel_qdisc_ops __read_mostly = { | |
247 | .id = "codel", | |
248 | .priv_size = sizeof(struct codel_sched_data), | |
249 | ||
250 | .enqueue = codel_qdisc_enqueue, | |
251 | .dequeue = codel_qdisc_dequeue, | |
252 | .peek = qdisc_peek_dequeued, | |
253 | .init = codel_init, | |
254 | .reset = codel_reset, | |
255 | .change = codel_change, | |
256 | .dump = codel_dump, | |
257 | .dump_stats = codel_dump_stats, | |
258 | .owner = THIS_MODULE, | |
259 | }; | |
241a94ab | 260 | MODULE_ALIAS_NET_SCH("codel"); |
76e3cc12 ED |
261 | |
262 | static int __init codel_module_init(void) | |
263 | { | |
264 | return register_qdisc(&codel_qdisc_ops); | |
265 | } | |
266 | ||
267 | static void __exit codel_module_exit(void) | |
268 | { | |
269 | unregister_qdisc(&codel_qdisc_ops); | |
270 | } | |
271 | ||
272 | module_init(codel_module_init) | |
273 | module_exit(codel_module_exit) | |
274 | ||
275 | MODULE_DESCRIPTION("Controlled Delay queue discipline"); | |
276 | MODULE_AUTHOR("Dave Taht"); | |
277 | MODULE_AUTHOR("Eric Dumazet"); | |
278 | MODULE_LICENSE("Dual BSD/GPL"); |