// SPDX-License-Identifier: GPL-2.0-or-later /* * net/sched/sch_htb.c Hierarchical token bucket, feed tree version * * Authors: Martin Devera, <[email protected]> * * Credits (in time order) for older HTB versions: * Stef Coene <[email protected]> * HTB support at LARTC mailing list * Ondrej Kraus, <[email protected]> * found missing INIT_QDISC(htb) * Vladimir Smelhaus, Aamer Akhter, Bert Hubert * helped a lot to locate nasty class stall bug * Andi Kleen, Jamal Hadi, Bert Hubert * code review and helpful comments on shaping * Tomasz Wrona, <[email protected]> * created test case so that I was able to fix nasty bug * Wilfried Weissmann * spotted bug in dequeue code and helped with fix * Jiri Fojtasek * fixed requeue routine * and many others. thanks. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/skbuff.h> #include <linux/list.h> #include <linux/compiler.h> #include <linux/rbtree.h> #include <linux/workqueue.h> #include <linux/slab.h> #include <net/netlink.h> #include <net/sch_generic.h> #include <net/pkt_sched.h> #include <net/pkt_cls.h> /* HTB algorithm. Author: [email protected] ======================================================================== HTB is like TBF with multiple classes. It is also similar to CBQ because it allows to assign priority to each class in hierarchy. In fact it is another implementation of Floyd's formal sharing. Levels: Each class is assigned level. Leaf has ALWAYS level 0 and root classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level one less than their parent. */ static int htb_hysteresis __read_mostly = …; /* whether to use mode hysteresis for speedup */ #define HTB_VER … #if HTB_VER >> 16 != TC_HTB_PROTOVER #error "Mismatched sch_htb.c and pkt_sch.h" #endif /* Module parameter and sysfs export */ module_param (htb_hysteresis, int, 0640); MODULE_PARM_DESC(…) …; static int htb_rate_est = …; /* htb classes have a default rate estimator */ module_param(htb_rate_est, int, 0640); MODULE_PARM_DESC(…) …; /* used internaly to keep status of single class */ enum htb_cmode { … }; struct htb_prio { … }; /* interior & leaf nodes; props specific to leaves are marked L: * To reduce false sharing, place mostly read fields at beginning, * and mostly written ones at the end. */ struct htb_class { … }; struct htb_level { … }; struct htb_sched { … }; /* find class in global hash table using given handle */ static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch) { … } static unsigned long htb_search(struct Qdisc *sch, u32 handle) { … } #define HTB_DIRECT … /** * htb_classify - classify a packet into class * @skb: the socket buffer * @sch: the active queue discipline * @qerr: pointer for returned status code * * It returns NULL if the packet should be dropped or -1 if the packet * should be passed directly thru. In all other cases leaf class is returned. * We allow direct class selection by classid in priority. The we examine * filters in qdisc and in inner nodes (if higher filter points to the inner * node). If we end up with classid MAJOR:0 we enqueue the skb into special * internal fifo (direct). These packets then go directly thru. If we still * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessful * then finish and return direct queue. */ static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) { … } /** * htb_add_to_id_tree - adds class to the round robin list * @root: the root of the tree * @cl: the class to add * @prio: the give prio in class * * Routine adds class to the list (actually tree) sorted by classid. * Make sure that class is not already on such list for given prio. */ static void htb_add_to_id_tree(struct rb_root *root, struct htb_class *cl, int prio) { … } /** * htb_add_to_wait_tree - adds class to the event queue with delay * @q: the priority event queue * @cl: the class to add * @delay: delay in microseconds * * The class is added to priority event queue to indicate that class will * change its mode in cl->pq_key microseconds. Make sure that class is not * already in the queue. */ static void htb_add_to_wait_tree(struct htb_sched *q, struct htb_class *cl, s64 delay) { … } /** * htb_next_rb_node - finds next node in binary tree * @n: the current node in binary tree * * When we are past last key we return NULL. * Average complexity is 2 steps per call. */ static inline void htb_next_rb_node(struct rb_node **n) { … } /** * htb_add_class_to_row - add class to its row * @q: the priority event queue * @cl: the class to add * @mask: the given priorities in class in bitmap * * The class is added to row at priorities marked in mask. * It does nothing if mask == 0. */ static inline void htb_add_class_to_row(struct htb_sched *q, struct htb_class *cl, int mask) { … } /* If this triggers, it is a bug in this code, but it need not be fatal */ static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root) { … } /** * htb_remove_class_from_row - removes class from its row * @q: the priority event queue * @cl: the class to add * @mask: the given priorities in class in bitmap * * The class is removed from row at priorities marked in mask. * It does nothing if mask == 0. */ static inline void htb_remove_class_from_row(struct htb_sched *q, struct htb_class *cl, int mask) { … } /** * htb_activate_prios - creates active classe's feed chain * @q: the priority event queue * @cl: the class to activate * * The class is connected to ancestors and/or appropriate rows * for priorities it is participating on. cl->cmode must be new * (activated) mode. It does nothing if cl->prio_activity == 0. */ static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl) { … } /** * htb_deactivate_prios - remove class from feed chain * @q: the priority event queue * @cl: the class to deactivate * * cl->cmode must represent old mode (before deactivation). It does * nothing if cl->prio_activity == 0. Class is removed from all feed * chains and rows. */ static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl) { … } static inline s64 htb_lowater(const struct htb_class *cl) { … } static inline s64 htb_hiwater(const struct htb_class *cl) { … } /** * htb_class_mode - computes and returns current class mode * @cl: the target class * @diff: diff time in microseconds * * It computes cl's mode at time cl->t_c+diff and returns it. If mode * is not HTB_CAN_SEND then cl->pq_key is updated to time difference * from now to time when cl will change its state. * Also it is worth to note that class mode doesn't change simply * at cl->{c,}tokens == 0 but there can rather be hysteresis of * 0 .. -cl->{c,}buffer range. It is meant to limit number of * mode transitions per time unit. The speed gain is about 1/6. */ static inline enum htb_cmode htb_class_mode(struct htb_class *cl, s64 *diff) { … } /** * htb_change_class_mode - changes classe's mode * @q: the priority event queue * @cl: the target class * @diff: diff time in microseconds * * This should be the only way how to change classe's mode under normal * circumstances. Routine will update feed lists linkage, change mode * and add class to the wait event queue if appropriate. New mode should * be different from old one and cl->pq_key has to be valid if changing * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree). */ static void htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, s64 *diff) { … } /** * htb_activate - inserts leaf cl into appropriate active feeds * @q: the priority event queue * @cl: the target class * * Routine learns (new) priority of leaf and activates feed chain * for the prio. It can be called on already active leaf safely. * It also adds leaf into droplist. */ static inline void htb_activate(struct htb_sched *q, struct htb_class *cl) { … } /** * htb_deactivate - remove leaf cl from active feeds * @q: the priority event queue * @cl: the target class * * Make sure that leaf is active. In the other words it can't be called * with non-active leaf. It also removes class from the drop list. */ static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl) { … } static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { … } static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, s64 diff) { … } static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff) { … } /** * htb_charge_class - charges amount "bytes" to leaf and ancestors * @q: the priority event queue * @cl: the class to start iterate * @level: the minimum level to account * @skb: the socket buffer * * Routine assumes that packet "bytes" long was dequeued from leaf cl * borrowing from "level". It accounts bytes to ceil leaky bucket for * leaf and all ancestors and to rate bucket for ancestors at levels * "level" and higher. It also handles possible change of mode resulting * from the update. Note that mode can also increase here (MAY_BORROW to * CAN_SEND) because we can use more precise clock that event queue here. * In such case we remove class from event queue first. */ static void htb_charge_class(struct htb_sched *q, struct htb_class *cl, int level, struct sk_buff *skb) { … } /** * htb_do_events - make mode changes to classes at the level * @q: the priority event queue * @level: which wait_pq in 'q->hlevel' * @start: start jiffies * * Scans event queue for pending events and applies them. Returns time of * next pending event (0 for no event in pq, q->now for too many events). * Note: Applied are events whose have cl->pq_key <= q->now. */ static s64 htb_do_events(struct htb_sched *q, const int level, unsigned long start) { … } /* Returns class->node+prio from id-tree where classe's id is >= id. NULL * is no such one exists. */ static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n, u32 id) { … } /** * htb_lookup_leaf - returns next leaf class in DRR order * @hprio: the current one * @prio: which prio in class * * Find leaf where current feed pointers points to. */ static struct htb_class *htb_lookup_leaf(struct htb_prio *hprio, const int prio) { … } /* dequeues packet at given priority and level; call only if * you are sure that there is active class at prio/level */ static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, const int prio, const int level) { … } static struct sk_buff *htb_dequeue(struct Qdisc *sch) { … } /* reset all classes */ /* always caled under BH & queue lock */ static void htb_reset(struct Qdisc *sch) { … } static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = …; static void htb_work_func(struct work_struct *work) { … } static int htb_offload(struct net_device *dev, struct tc_htb_qopt_offload *opt) { … } static int htb_init(struct Qdisc *sch, struct nlattr *opt, struct netlink_ext_ack *extack) { … } static void htb_attach_offload(struct Qdisc *sch) { … } static void htb_attach_software(struct Qdisc *sch) { … } static void htb_attach(struct Qdisc *sch) { … } static int htb_dump(struct Qdisc *sch, struct sk_buff *skb) { … } static int htb_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb, struct tcmsg *tcm) { … } static void htb_offload_aggregate_stats(struct htb_sched *q, struct htb_class *cl) { … } static int htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d) { … } static struct netdev_queue * htb_select_queue(struct Qdisc *sch, struct tcmsg *tcm) { … } static struct Qdisc * htb_graft_helper(struct netdev_queue *dev_queue, struct Qdisc *new_q) { … } static struct netdev_queue *htb_offload_get_queue(struct htb_class *cl) { … } static void htb_offload_move_qdisc(struct Qdisc *sch, struct htb_class *cl_old, struct htb_class *cl_new, bool destroying) { … } static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, struct Qdisc **old, struct netlink_ext_ack *extack) { … } static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg) { … } static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg) { … } static inline int htb_parent_last_child(struct htb_class *cl) { … } static void htb_parent_to_leaf(struct Qdisc *sch, struct htb_class *cl, struct Qdisc *new_q) { … } static void htb_parent_to_leaf_offload(struct Qdisc *sch, struct netdev_queue *dev_queue, struct Qdisc *new_q) { … } static int htb_destroy_class_offload(struct Qdisc *sch, struct htb_class *cl, bool last_child, bool destroying, struct netlink_ext_ack *extack) { … } static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl) { … } static void htb_destroy(struct Qdisc *sch) { … } static int htb_delete(struct Qdisc *sch, unsigned long arg, struct netlink_ext_ack *extack) { … } static int htb_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca, unsigned long *arg, struct netlink_ext_ack *extack) { … } static struct tcf_block *htb_tcf_block(struct Qdisc *sch, unsigned long arg, struct netlink_ext_ack *extack) { … } static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent, u32 classid) { … } static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg) { … } static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg) { … } static const struct Qdisc_class_ops htb_class_ops = …; static struct Qdisc_ops htb_qdisc_ops __read_mostly = …; MODULE_ALIAS_NET_SCH(…) …; static int __init htb_module_init(void) { … } static void __exit htb_module_exit(void) { … } module_init(…) … module_exit(…) MODULE_LICENSE(…) …; MODULE_DESCRIPTION(…) …;
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