--- /dev/null
+/*
+ * net/sched/sch_gred.c Generic Random Early Detection queue.
+ *
+ *
+ * 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: J Hadi Salim (hadi@cyberus.ca) 1998-2002
+ *
+ * 991129: - Bug fix with grio mode
+ * - a better sing. AvgQ mode with Grio(WRED)
+ * - A finer grained VQ dequeue based on sugestion
+ * from Ren Liu
+ * - More error checks
+ *
+ * For all the glorious comments look at include/net/red.h
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+#include <net/red.h>
+
+#define GRED_DEF_PRIO (MAX_DPs / 2)
+#define GRED_VQ_MASK (MAX_DPs - 1)
+
+struct gred_sched_data;
+struct gred_sched;
+
+struct gred_sched_data {
+ u32 limit; /* HARD maximal queue length */
+ u32 DP; /* the drop parameters */
+ u32 bytesin; /* bytes seen on virtualQ so far*/
+ u32 packetsin; /* packets seen on virtualQ so far*/
+ u32 backlog; /* bytes on the virtualQ */
+ u8 prio; /* the prio of this vq */
+
+ struct red_parms parms;
+ struct red_vars vars;
+ struct red_stats stats;
+};
+
+enum {
+ GRED_WRED_MODE = 1,
+ GRED_RIO_MODE,
+};
+
+struct gred_sched {
+ struct gred_sched_data *tab[MAX_DPs];
+ unsigned long flags;
+ u32 red_flags;
+ u32 DPs;
+ u32 def;
+ struct red_vars wred_set;
+};
+
+static inline int gred_wred_mode(struct gred_sched *table)
+{
+ return test_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline void gred_enable_wred_mode(struct gred_sched *table)
+{
+ __set_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline void gred_disable_wred_mode(struct gred_sched *table)
+{
+ __clear_bit(GRED_WRED_MODE, &table->flags);
+}
+
+static inline int gred_rio_mode(struct gred_sched *table)
+{
+ return test_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline void gred_enable_rio_mode(struct gred_sched *table)
+{
+ __set_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline void gred_disable_rio_mode(struct gred_sched *table)
+{
+ __clear_bit(GRED_RIO_MODE, &table->flags);
+}
+
+static inline int gred_wred_mode_check(struct Qdisc *sch)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ int i;
+
+ /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
+ for (i = 0; i < table->DPs; i++) {
+ struct gred_sched_data *q = table->tab[i];
+ int n;
+
+ if (q == NULL)
+ continue;
+
+ for (n = i + 1; n < table->DPs; n++)
+ if (table->tab[n] && table->tab[n]->prio == q->prio)
+ return 1;
+ }
+
+ return 0;
+}
+
+static inline unsigned int gred_backlog(struct gred_sched *table,
+ struct gred_sched_data *q,
+ struct Qdisc *sch)
+{
+ if (gred_wred_mode(table))
+ return sch->qstats.backlog;
+ else
+ return q->backlog;
+}
+
+static inline u16 tc_index_to_dp(struct sk_buff *skb)
+{
+ return skb->tc_index & GRED_VQ_MASK;
+}
+
+static inline void gred_load_wred_set(const struct gred_sched *table,
+ struct gred_sched_data *q)
+{
+ q->vars.qavg = table->wred_set.qavg;
+ q->vars.qidlestart = table->wred_set.qidlestart;
+}
+
+static inline void gred_store_wred_set(struct gred_sched *table,
+ struct gred_sched_data *q)
+{
+ table->wred_set.qavg = q->vars.qavg;
+ table->wred_set.qidlestart = q->vars.qidlestart;
+}
+
+static inline int gred_use_ecn(struct gred_sched *t)
+{
+ return t->red_flags & TC_RED_ECN;
+}
+
+static inline int gred_use_harddrop(struct gred_sched *t)
+{
+ return t->red_flags & TC_RED_HARDDROP;
+}
+
+static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct gred_sched_data *q = NULL;
+ struct gred_sched *t = qdisc_priv(sch);
+ unsigned long qavg = 0;
+ u16 dp = tc_index_to_dp(skb);
+
+ if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+ dp = t->def;
+
+ q = t->tab[dp];
+ if (!q) {
+ /* Pass through packets not assigned to a DP
+ * if no default DP has been configured. This
+ * allows for DP flows to be left untouched.
+ */
+ if (skb_queue_len(&sch->q) < qdisc_dev(sch)->tx_queue_len)
+ return qdisc_enqueue_tail(skb, sch);
+ else
+ goto drop;
+ }
+
+ /* fix tc_index? --could be controversial but needed for
+ requeueing */
+ skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
+ }
+
+ /* sum up all the qaves of prios < ours to get the new qave */
+ if (!gred_wred_mode(t) && gred_rio_mode(t)) {
+ int i;
+
+ for (i = 0; i < t->DPs; i++) {
+ if (t->tab[i] && t->tab[i]->prio < q->prio &&
+ !red_is_idling(&t->tab[i]->vars))
+ qavg += t->tab[i]->vars.qavg;
+ }
+
+ }
+
+ q->packetsin++;
+ q->bytesin += qdisc_pkt_len(skb);
+
+ if (gred_wred_mode(t))
+ gred_load_wred_set(t, q);
+
+ q->vars.qavg = red_calc_qavg(&q->parms,
+ &q->vars,
+ gred_backlog(t, q, sch));
+
+ if (red_is_idling(&q->vars))
+ red_end_of_idle_period(&q->vars);
+
+ if (gred_wred_mode(t))
+ gred_store_wred_set(t, q);
+
+ switch (red_action(&q->parms, &q->vars, q->vars.qavg + qavg)) {
+ case RED_DONT_MARK:
+ break;
+
+ case RED_PROB_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
+ q->stats.prob_drop++;
+ goto congestion_drop;
+ }
+
+ q->stats.prob_mark++;
+ break;
+
+ case RED_HARD_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
+ !INET_ECN_set_ce(skb)) {
+ q->stats.forced_drop++;
+ goto congestion_drop;
+ }
+ q->stats.forced_mark++;
+ break;
+ }
+
+ if (gred_backlog(t, q, sch) + qdisc_pkt_len(skb) <= q->limit) {
+ q->backlog += qdisc_pkt_len(skb);
+ return qdisc_enqueue_tail(skb, sch);
+ }
+
+ q->stats.pdrop++;
+drop:
+ return qdisc_drop(skb, sch);
+
+congestion_drop:
+ qdisc_drop(skb, sch);
+ return NET_XMIT_CN;
+}
+
+static struct sk_buff *gred_dequeue(struct Qdisc *sch)
+{
+ struct sk_buff *skb;
+ struct gred_sched *t = qdisc_priv(sch);
+
+ skb = qdisc_dequeue_head(sch);
+
+ if (skb) {
+ struct gred_sched_data *q;
+ u16 dp = tc_index_to_dp(skb);
+
+ if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+ net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x after dequeue, screwing up backlog\n",
+ tc_index_to_dp(skb));
+ } else {
+ q->backlog -= qdisc_pkt_len(skb);
+
+ if (gred_wred_mode(t)) {
+ if (!sch->qstats.backlog)
+ red_start_of_idle_period(&t->wred_set);
+ } else {
+ if (!q->backlog)
+ red_start_of_idle_period(&q->vars);
+ }
+ }
+
+ return skb;
+ }
+
+ return NULL;
+}
+
+static unsigned int gred_drop(struct Qdisc *sch)
+{
+ struct sk_buff *skb;
+ struct gred_sched *t = qdisc_priv(sch);
+
+ skb = qdisc_dequeue_tail(sch);
+ if (skb) {
+ unsigned int len = qdisc_pkt_len(skb);
+ struct gred_sched_data *q;
+ u16 dp = tc_index_to_dp(skb);
+
+ if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+ net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x while dropping, screwing up backlog\n",
+ tc_index_to_dp(skb));
+ } else {
+ q->backlog -= len;
+ q->stats.other++;
+
+ if (gred_wred_mode(t)) {
+ if (!sch->qstats.backlog)
+ red_start_of_idle_period(&t->wred_set);
+ } else {
+ if (!q->backlog)
+ red_start_of_idle_period(&q->vars);
+ }
+ }
+
+ qdisc_drop(skb, sch);
+ return len;
+ }
+
+ return 0;
+}
+
+static void gred_reset(struct Qdisc *sch)
+{
+ int i;
+ struct gred_sched *t = qdisc_priv(sch);
+
+ qdisc_reset_queue(sch);
+
+ for (i = 0; i < t->DPs; i++) {
+ struct gred_sched_data *q = t->tab[i];
+
+ if (!q)
+ continue;
+
+ red_restart(&q->vars);
+ q->backlog = 0;
+ }
+}
+
+static inline void gred_destroy_vq(struct gred_sched_data *q)
+{
+ kfree(q);
+}
+
+static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ struct tc_gred_sopt *sopt;
+ int i;
+
+ if (dps == NULL)
+ return -EINVAL;
+
+ sopt = nla_data(dps);
+
+ if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
+ return -EINVAL;
+
+ sch_tree_lock(sch);
+ table->DPs = sopt->DPs;
+ table->def = sopt->def_DP;
+ table->red_flags = sopt->flags;
+
+ /*
+ * Every entry point to GRED is synchronized with the above code
+ * and the DP is checked against DPs, i.e. shadowed VQs can no
+ * longer be found so we can unlock right here.
+ */
+ sch_tree_unlock(sch);
+
+ if (sopt->grio) {
+ gred_enable_rio_mode(table);
+ gred_disable_wred_mode(table);
+ if (gred_wred_mode_check(sch))
+ gred_enable_wred_mode(table);
+ } else {
+ gred_disable_rio_mode(table);
+ gred_disable_wred_mode(table);
+ }
+
+ for (i = table->DPs; i < MAX_DPs; i++) {
+ if (table->tab[i]) {
+ pr_warn("GRED: Warning: Destroying shadowed VQ 0x%x\n",
+ i);
+ gred_destroy_vq(table->tab[i]);
+ table->tab[i] = NULL;
+ }
+ }
+
+ return 0;
+}
+
+static inline int gred_change_vq(struct Qdisc *sch, int dp,
+ struct tc_gred_qopt *ctl, int prio,
+ u8 *stab, u32 max_P,
+ struct gred_sched_data **prealloc)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ struct gred_sched_data *q = table->tab[dp];
+
+ if (!q) {
+ table->tab[dp] = q = *prealloc;
+ *prealloc = NULL;
+ if (!q)
+ return -ENOMEM;
+ }
+
+ q->DP = dp;
+ q->prio = prio;
+ q->limit = ctl->limit;
+
+ if (q->backlog == 0)
+ red_end_of_idle_period(&q->vars);
+
+ red_set_parms(&q->parms,
+ ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
+ ctl->Scell_log, stab, max_P);
+ red_set_vars(&q->vars);
+ return 0;
+}
+
+static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
+ [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
+ [TCA_GRED_STAB] = { .len = 256 },
+ [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
+ [TCA_GRED_MAX_P] = { .type = NLA_U32 },
+};
+
+static int gred_change(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ struct tc_gred_qopt *ctl;
+ struct nlattr *tb[TCA_GRED_MAX + 1];
+ int err, prio = GRED_DEF_PRIO;
+ u8 *stab;
+ u32 max_P;
+ struct gred_sched_data *prealloc;
+
+ if (opt == NULL)
+ return -EINVAL;
+
+ err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
+ if (err < 0)
+ return err;
+
+ if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
+ return gred_change_table_def(sch, opt);
+
+ if (tb[TCA_GRED_PARMS] == NULL ||
+ tb[TCA_GRED_STAB] == NULL)
+ return -EINVAL;
+
+ max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
+
+ err = -EINVAL;
+ ctl = nla_data(tb[TCA_GRED_PARMS]);
+ stab = nla_data(tb[TCA_GRED_STAB]);
+
+ if (ctl->DP >= table->DPs)
+ goto errout;
+
+ if (gred_rio_mode(table)) {
+ if (ctl->prio == 0) {
+ int def_prio = GRED_DEF_PRIO;
+
+ if (table->tab[table->def])
+ def_prio = table->tab[table->def]->prio;
+
+ printk(KERN_DEBUG "GRED: DP %u does not have a prio "
+ "setting default to %d\n", ctl->DP, def_prio);
+
+ prio = def_prio;
+ } else
+ prio = ctl->prio;
+ }
+
+ prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
+ sch_tree_lock(sch);
+
+ err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
+ if (err < 0)
+ goto errout_locked;
+
+ if (gred_rio_mode(table)) {
+ gred_disable_wred_mode(table);
+ if (gred_wred_mode_check(sch))
+ gred_enable_wred_mode(table);
+ }
+
+ err = 0;
+
+errout_locked:
+ sch_tree_unlock(sch);
+ kfree(prealloc);
+errout:
+ return err;
+}
+
+static int gred_init(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct nlattr *tb[TCA_GRED_MAX + 1];
+ int err;
+
+ if (opt == NULL)
+ return -EINVAL;
+
+ err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
+ if (err < 0)
+ return err;
+
+ if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
+ return -EINVAL;
+
+ return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
+}
+
+static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ struct nlattr *parms, *opts = NULL;
+ int i;
+ u32 max_p[MAX_DPs];
+ struct tc_gred_sopt sopt = {
+ .DPs = table->DPs,
+ .def_DP = table->def,
+ .grio = gred_rio_mode(table),
+ .flags = table->red_flags,
+ };
+
+ opts = nla_nest_start(skb, TCA_OPTIONS);
+ if (opts == NULL)
+ goto nla_put_failure;
+ if (nla_put(skb, TCA_GRED_DPS, sizeof(sopt), &sopt))
+ goto nla_put_failure;
+
+ for (i = 0; i < MAX_DPs; i++) {
+ struct gred_sched_data *q = table->tab[i];
+
+ max_p[i] = q ? q->parms.max_P : 0;
+ }
+ if (nla_put(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p))
+ goto nla_put_failure;
+
+ parms = nla_nest_start(skb, TCA_GRED_PARMS);
+ if (parms == NULL)
+ goto nla_put_failure;
+
+ for (i = 0; i < MAX_DPs; i++) {
+ struct gred_sched_data *q = table->tab[i];
+ struct tc_gred_qopt opt;
+ unsigned long qavg;
+
+ memset(&opt, 0, sizeof(opt));
+
+ if (!q) {
+ /* hack -- fix at some point with proper message
+ This is how we indicate to tc that there is no VQ
+ at this DP */
+
+ opt.DP = MAX_DPs + i;
+ goto append_opt;
+ }
+
+ opt.limit = q->limit;
+ opt.DP = q->DP;
+ opt.backlog = gred_backlog(table, q, sch);
+ opt.prio = q->prio;
+ opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
+ opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
+ opt.Wlog = q->parms.Wlog;
+ opt.Plog = q->parms.Plog;
+ opt.Scell_log = q->parms.Scell_log;
+ opt.other = q->stats.other;
+ opt.early = q->stats.prob_drop;
+ opt.forced = q->stats.forced_drop;
+ opt.pdrop = q->stats.pdrop;
+ opt.packets = q->packetsin;
+ opt.bytesin = q->bytesin;
+
+ if (gred_wred_mode(table))
+ gred_load_wred_set(table, q);
+
+ qavg = red_calc_qavg(&q->parms, &q->vars,
+ q->vars.qavg >> q->parms.Wlog);
+ opt.qave = qavg >> q->parms.Wlog;
+
+append_opt:
+ if (nla_append(skb, sizeof(opt), &opt) < 0)
+ goto nla_put_failure;
+ }
+
+ nla_nest_end(skb, parms);
+
+ return nla_nest_end(skb, opts);
+
+nla_put_failure:
+ nla_nest_cancel(skb, opts);
+ return -EMSGSIZE;
+}
+
+static void gred_destroy(struct Qdisc *sch)
+{
+ struct gred_sched *table = qdisc_priv(sch);
+ int i;
+
+ for (i = 0; i < table->DPs; i++) {
+ if (table->tab[i])
+ gred_destroy_vq(table->tab[i]);
+ }
+}
+
+static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
+ .id = "gred",
+ .priv_size = sizeof(struct gred_sched),
+ .enqueue = gred_enqueue,
+ .dequeue = gred_dequeue,
+ .peek = qdisc_peek_head,
+ .drop = gred_drop,
+ .init = gred_init,
+ .reset = gred_reset,
+ .destroy = gred_destroy,
+ .change = gred_change,
+ .dump = gred_dump,
+ .owner = THIS_MODULE,
+};
+
+static int __init gred_module_init(void)
+{
+ return register_qdisc(&gred_qdisc_ops);
+}
+
+static void __exit gred_module_exit(void)
+{
+ unregister_qdisc(&gred_qdisc_ops);
+}
+
+module_init(gred_module_init)
+module_exit(gred_module_exit)
+
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff