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![Jason A. Donenfeld](/assets/img/avatar_default.png)
This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs Reviewed-by: SeongJae Park <sj@kernel.org> # for damon Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
1294 lines
31 KiB
C
1294 lines
31 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/sched/sch_netem.c Network emulator
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*
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* Many of the algorithms and ideas for this came from
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* NIST Net which is not copyrighted.
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*
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* Authors: Stephen Hemminger <shemminger@osdl.org>
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* Catalin(ux aka Dino) BOIE <catab at umbrella dot ro>
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <linux/rtnetlink.h>
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#include <linux/reciprocal_div.h>
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#include <linux/rbtree.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <net/inet_ecn.h>
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#define VERSION "1.3"
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/* Network Emulation Queuing algorithm.
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====================================
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Sources: [1] Mark Carson, Darrin Santay, "NIST Net - A Linux-based
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Network Emulation Tool
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[2] Luigi Rizzo, DummyNet for FreeBSD
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----------------------------------------------------------------
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This started out as a simple way to delay outgoing packets to
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test TCP but has grown to include most of the functionality
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of a full blown network emulator like NISTnet. It can delay
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packets and add random jitter (and correlation). The random
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distribution can be loaded from a table as well to provide
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normal, Pareto, or experimental curves. Packet loss,
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duplication, and reordering can also be emulated.
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This qdisc does not do classification that can be handled in
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layering other disciplines. It does not need to do bandwidth
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control either since that can be handled by using token
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bucket or other rate control.
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Correlated Loss Generator models
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Added generation of correlated loss according to the
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"Gilbert-Elliot" model, a 4-state markov model.
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References:
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[1] NetemCLG Home http://netgroup.uniroma2.it/NetemCLG
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[2] S. Salsano, F. Ludovici, A. Ordine, "Definition of a general
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and intuitive loss model for packet networks and its implementation
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in the Netem module in the Linux kernel", available in [1]
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Authors: Stefano Salsano <stefano.salsano at uniroma2.it
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Fabio Ludovici <fabio.ludovici at yahoo.it>
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*/
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struct disttable {
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u32 size;
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s16 table[];
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};
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struct netem_sched_data {
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/* internal t(ime)fifo qdisc uses t_root and sch->limit */
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struct rb_root t_root;
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/* a linear queue; reduces rbtree rebalancing when jitter is low */
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struct sk_buff *t_head;
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struct sk_buff *t_tail;
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/* optional qdisc for classful handling (NULL at netem init) */
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struct Qdisc *qdisc;
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struct qdisc_watchdog watchdog;
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s64 latency;
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s64 jitter;
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u32 loss;
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u32 ecn;
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u32 limit;
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u32 counter;
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u32 gap;
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u32 duplicate;
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u32 reorder;
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u32 corrupt;
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u64 rate;
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s32 packet_overhead;
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u32 cell_size;
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struct reciprocal_value cell_size_reciprocal;
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s32 cell_overhead;
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struct crndstate {
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u32 last;
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u32 rho;
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} delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;
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struct disttable *delay_dist;
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enum {
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CLG_RANDOM,
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CLG_4_STATES,
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CLG_GILB_ELL,
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} loss_model;
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enum {
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TX_IN_GAP_PERIOD = 1,
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TX_IN_BURST_PERIOD,
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LOST_IN_GAP_PERIOD,
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LOST_IN_BURST_PERIOD,
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} _4_state_model;
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enum {
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GOOD_STATE = 1,
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BAD_STATE,
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} GE_state_model;
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/* Correlated Loss Generation models */
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struct clgstate {
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/* state of the Markov chain */
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u8 state;
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/* 4-states and Gilbert-Elliot models */
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u32 a1; /* p13 for 4-states or p for GE */
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u32 a2; /* p31 for 4-states or r for GE */
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u32 a3; /* p32 for 4-states or h for GE */
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u32 a4; /* p14 for 4-states or 1-k for GE */
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u32 a5; /* p23 used only in 4-states */
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} clg;
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struct tc_netem_slot slot_config;
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struct slotstate {
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u64 slot_next;
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s32 packets_left;
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s32 bytes_left;
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} slot;
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struct disttable *slot_dist;
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};
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/* Time stamp put into socket buffer control block
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* Only valid when skbs are in our internal t(ime)fifo queue.
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*
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* As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp,
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* and skb->next & skb->prev are scratch space for a qdisc,
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* we save skb->tstamp value in skb->cb[] before destroying it.
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*/
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struct netem_skb_cb {
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u64 time_to_send;
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};
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static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
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{
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/* we assume we can use skb next/prev/tstamp as storage for rb_node */
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qdisc_cb_private_validate(skb, sizeof(struct netem_skb_cb));
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return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
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}
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/* init_crandom - initialize correlated random number generator
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* Use entropy source for initial seed.
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*/
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static void init_crandom(struct crndstate *state, unsigned long rho)
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{
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state->rho = rho;
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state->last = get_random_u32();
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}
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/* get_crandom - correlated random number generator
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* Next number depends on last value.
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* rho is scaled to avoid floating point.
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*/
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static u32 get_crandom(struct crndstate *state)
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{
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u64 value, rho;
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unsigned long answer;
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if (!state || state->rho == 0) /* no correlation */
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return get_random_u32();
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value = get_random_u32();
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rho = (u64)state->rho + 1;
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answer = (value * ((1ull<<32) - rho) + state->last * rho) >> 32;
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state->last = answer;
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return answer;
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}
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/* loss_4state - 4-state model loss generator
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* Generates losses according to the 4-state Markov chain adopted in
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* the GI (General and Intuitive) loss model.
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*/
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static bool loss_4state(struct netem_sched_data *q)
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{
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struct clgstate *clg = &q->clg;
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u32 rnd = get_random_u32();
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/*
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* Makes a comparison between rnd and the transition
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* probabilities outgoing from the current state, then decides the
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* next state and if the next packet has to be transmitted or lost.
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* The four states correspond to:
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* TX_IN_GAP_PERIOD => successfully transmitted packets within a gap period
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* LOST_IN_GAP_PERIOD => isolated losses within a gap period
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* LOST_IN_BURST_PERIOD => lost packets within a burst period
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* TX_IN_BURST_PERIOD => successfully transmitted packets within a burst period
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*/
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switch (clg->state) {
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case TX_IN_GAP_PERIOD:
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if (rnd < clg->a4) {
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clg->state = LOST_IN_GAP_PERIOD;
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return true;
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} else if (clg->a4 < rnd && rnd < clg->a1 + clg->a4) {
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clg->state = LOST_IN_BURST_PERIOD;
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return true;
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} else if (clg->a1 + clg->a4 < rnd) {
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clg->state = TX_IN_GAP_PERIOD;
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}
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break;
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case TX_IN_BURST_PERIOD:
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if (rnd < clg->a5) {
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clg->state = LOST_IN_BURST_PERIOD;
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return true;
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} else {
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clg->state = TX_IN_BURST_PERIOD;
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}
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break;
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case LOST_IN_BURST_PERIOD:
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if (rnd < clg->a3)
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clg->state = TX_IN_BURST_PERIOD;
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else if (clg->a3 < rnd && rnd < clg->a2 + clg->a3) {
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clg->state = TX_IN_GAP_PERIOD;
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} else if (clg->a2 + clg->a3 < rnd) {
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clg->state = LOST_IN_BURST_PERIOD;
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return true;
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}
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break;
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case LOST_IN_GAP_PERIOD:
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clg->state = TX_IN_GAP_PERIOD;
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break;
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}
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return false;
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}
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/* loss_gilb_ell - Gilbert-Elliot model loss generator
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* Generates losses according to the Gilbert-Elliot loss model or
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* its special cases (Gilbert or Simple Gilbert)
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*
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* Makes a comparison between random number and the transition
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* probabilities outgoing from the current state, then decides the
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* next state. A second random number is extracted and the comparison
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* with the loss probability of the current state decides if the next
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* packet will be transmitted or lost.
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*/
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static bool loss_gilb_ell(struct netem_sched_data *q)
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{
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struct clgstate *clg = &q->clg;
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switch (clg->state) {
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case GOOD_STATE:
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if (get_random_u32() < clg->a1)
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clg->state = BAD_STATE;
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if (get_random_u32() < clg->a4)
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return true;
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break;
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case BAD_STATE:
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if (get_random_u32() < clg->a2)
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clg->state = GOOD_STATE;
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if (get_random_u32() > clg->a3)
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return true;
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}
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return false;
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}
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static bool loss_event(struct netem_sched_data *q)
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{
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switch (q->loss_model) {
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case CLG_RANDOM:
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/* Random packet drop 0 => none, ~0 => all */
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return q->loss && q->loss >= get_crandom(&q->loss_cor);
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case CLG_4_STATES:
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/* 4state loss model algorithm (used also for GI model)
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* Extracts a value from the markov 4 state loss generator,
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* if it is 1 drops a packet and if needed writes the event in
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* the kernel logs
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*/
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return loss_4state(q);
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case CLG_GILB_ELL:
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/* Gilbert-Elliot loss model algorithm
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* Extracts a value from the Gilbert-Elliot loss generator,
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* if it is 1 drops a packet and if needed writes the event in
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* the kernel logs
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*/
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return loss_gilb_ell(q);
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}
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return false; /* not reached */
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}
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/* tabledist - return a pseudo-randomly distributed value with mean mu and
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* std deviation sigma. Uses table lookup to approximate the desired
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* distribution, and a uniformly-distributed pseudo-random source.
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*/
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static s64 tabledist(s64 mu, s32 sigma,
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struct crndstate *state,
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const struct disttable *dist)
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{
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s64 x;
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long t;
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u32 rnd;
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if (sigma == 0)
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return mu;
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rnd = get_crandom(state);
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/* default uniform distribution */
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if (dist == NULL)
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return ((rnd % (2 * (u32)sigma)) + mu) - sigma;
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t = dist->table[rnd % dist->size];
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x = (sigma % NETEM_DIST_SCALE) * t;
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if (x >= 0)
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x += NETEM_DIST_SCALE/2;
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else
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x -= NETEM_DIST_SCALE/2;
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return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu;
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}
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static u64 packet_time_ns(u64 len, const struct netem_sched_data *q)
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{
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len += q->packet_overhead;
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if (q->cell_size) {
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u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
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if (len > cells * q->cell_size) /* extra cell needed for remainder */
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cells++;
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len = cells * (q->cell_size + q->cell_overhead);
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}
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return div64_u64(len * NSEC_PER_SEC, q->rate);
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}
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static void tfifo_reset(struct Qdisc *sch)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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struct rb_node *p = rb_first(&q->t_root);
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while (p) {
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struct sk_buff *skb = rb_to_skb(p);
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p = rb_next(p);
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rb_erase(&skb->rbnode, &q->t_root);
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rtnl_kfree_skbs(skb, skb);
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}
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rtnl_kfree_skbs(q->t_head, q->t_tail);
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q->t_head = NULL;
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q->t_tail = NULL;
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}
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static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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u64 tnext = netem_skb_cb(nskb)->time_to_send;
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if (!q->t_tail || tnext >= netem_skb_cb(q->t_tail)->time_to_send) {
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if (q->t_tail)
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q->t_tail->next = nskb;
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else
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q->t_head = nskb;
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q->t_tail = nskb;
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} else {
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struct rb_node **p = &q->t_root.rb_node, *parent = NULL;
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while (*p) {
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struct sk_buff *skb;
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parent = *p;
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skb = rb_to_skb(parent);
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if (tnext >= netem_skb_cb(skb)->time_to_send)
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p = &parent->rb_right;
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else
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p = &parent->rb_left;
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}
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rb_link_node(&nskb->rbnode, parent, p);
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rb_insert_color(&nskb->rbnode, &q->t_root);
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}
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sch->q.qlen++;
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}
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/* netem can't properly corrupt a megapacket (like we get from GSO), so instead
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* when we statistically choose to corrupt one, we instead segment it, returning
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* the first packet to be corrupted, and re-enqueue the remaining frames
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*/
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static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch,
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struct sk_buff **to_free)
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{
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struct sk_buff *segs;
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netdev_features_t features = netif_skb_features(skb);
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segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
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if (IS_ERR_OR_NULL(segs)) {
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qdisc_drop(skb, sch, to_free);
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return NULL;
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}
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consume_skb(skb);
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return segs;
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}
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/*
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* Insert one skb into qdisc.
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* Note: parent depends on return value to account for queue length.
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* NET_XMIT_DROP: queue length didn't change.
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* NET_XMIT_SUCCESS: one skb was queued.
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*/
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static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
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struct sk_buff **to_free)
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{
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struct netem_sched_data *q = qdisc_priv(sch);
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/* We don't fill cb now as skb_unshare() may invalidate it */
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struct netem_skb_cb *cb;
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struct sk_buff *skb2;
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struct sk_buff *segs = NULL;
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unsigned int prev_len = qdisc_pkt_len(skb);
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int count = 1;
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int rc = NET_XMIT_SUCCESS;
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int rc_drop = NET_XMIT_DROP;
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/* Do not fool qdisc_drop_all() */
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skb->prev = NULL;
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/* Random duplication */
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if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor))
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++count;
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/* Drop packet? */
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if (loss_event(q)) {
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if (q->ecn && INET_ECN_set_ce(skb))
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qdisc_qstats_drop(sch); /* mark packet */
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else
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--count;
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}
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if (count == 0) {
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qdisc_qstats_drop(sch);
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__qdisc_drop(skb, to_free);
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return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
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}
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/* If a delay is expected, orphan the skb. (orphaning usually takes
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* place at TX completion time, so _before_ the link transit delay)
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*/
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if (q->latency || q->jitter || q->rate)
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skb_orphan_partial(skb);
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/*
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* If we need to duplicate packet, then re-insert at top of the
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* qdisc tree, since parent queuer expects that only one
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* skb will be queued.
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*/
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if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
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struct Qdisc *rootq = qdisc_root_bh(sch);
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u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
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q->duplicate = 0;
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rootq->enqueue(skb2, rootq, to_free);
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q->duplicate = dupsave;
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rc_drop = NET_XMIT_SUCCESS;
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}
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/*
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* Randomized packet corruption.
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* Make copy if needed since we are modifying
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* If packet is going to be hardware checksummed, then
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* do it now in software before we mangle it.
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*/
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if (q->corrupt && q->corrupt >= get_crandom(&q->corrupt_cor)) {
|
|
if (skb_is_gso(skb)) {
|
|
skb = netem_segment(skb, sch, to_free);
|
|
if (!skb)
|
|
return rc_drop;
|
|
segs = skb->next;
|
|
skb_mark_not_on_list(skb);
|
|
qdisc_skb_cb(skb)->pkt_len = skb->len;
|
|
}
|
|
|
|
skb = skb_unshare(skb, GFP_ATOMIC);
|
|
if (unlikely(!skb)) {
|
|
qdisc_qstats_drop(sch);
|
|
goto finish_segs;
|
|
}
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL &&
|
|
skb_checksum_help(skb)) {
|
|
qdisc_drop(skb, sch, to_free);
|
|
skb = NULL;
|
|
goto finish_segs;
|
|
}
|
|
|
|
skb->data[get_random_u32_below(skb_headlen(skb))] ^=
|
|
1<<get_random_u32_below(8);
|
|
}
|
|
|
|
if (unlikely(sch->q.qlen >= sch->limit)) {
|
|
/* re-link segs, so that qdisc_drop_all() frees them all */
|
|
skb->next = segs;
|
|
qdisc_drop_all(skb, sch, to_free);
|
|
return rc_drop;
|
|
}
|
|
|
|
qdisc_qstats_backlog_inc(sch, skb);
|
|
|
|
cb = netem_skb_cb(skb);
|
|
if (q->gap == 0 || /* not doing reordering */
|
|
q->counter < q->gap - 1 || /* inside last reordering gap */
|
|
q->reorder < get_crandom(&q->reorder_cor)) {
|
|
u64 now;
|
|
s64 delay;
|
|
|
|
delay = tabledist(q->latency, q->jitter,
|
|
&q->delay_cor, q->delay_dist);
|
|
|
|
now = ktime_get_ns();
|
|
|
|
if (q->rate) {
|
|
struct netem_skb_cb *last = NULL;
|
|
|
|
if (sch->q.tail)
|
|
last = netem_skb_cb(sch->q.tail);
|
|
if (q->t_root.rb_node) {
|
|
struct sk_buff *t_skb;
|
|
struct netem_skb_cb *t_last;
|
|
|
|
t_skb = skb_rb_last(&q->t_root);
|
|
t_last = netem_skb_cb(t_skb);
|
|
if (!last ||
|
|
t_last->time_to_send > last->time_to_send)
|
|
last = t_last;
|
|
}
|
|
if (q->t_tail) {
|
|
struct netem_skb_cb *t_last =
|
|
netem_skb_cb(q->t_tail);
|
|
|
|
if (!last ||
|
|
t_last->time_to_send > last->time_to_send)
|
|
last = t_last;
|
|
}
|
|
|
|
if (last) {
|
|
/*
|
|
* Last packet in queue is reference point (now),
|
|
* calculate this time bonus and subtract
|
|
* from delay.
|
|
*/
|
|
delay -= last->time_to_send - now;
|
|
delay = max_t(s64, 0, delay);
|
|
now = last->time_to_send;
|
|
}
|
|
|
|
delay += packet_time_ns(qdisc_pkt_len(skb), q);
|
|
}
|
|
|
|
cb->time_to_send = now + delay;
|
|
++q->counter;
|
|
tfifo_enqueue(skb, sch);
|
|
} else {
|
|
/*
|
|
* Do re-ordering by putting one out of N packets at the front
|
|
* of the queue.
|
|
*/
|
|
cb->time_to_send = ktime_get_ns();
|
|
q->counter = 0;
|
|
|
|
__qdisc_enqueue_head(skb, &sch->q);
|
|
sch->qstats.requeues++;
|
|
}
|
|
|
|
finish_segs:
|
|
if (segs) {
|
|
unsigned int len, last_len;
|
|
int nb;
|
|
|
|
len = skb ? skb->len : 0;
|
|
nb = skb ? 1 : 0;
|
|
|
|
while (segs) {
|
|
skb2 = segs->next;
|
|
skb_mark_not_on_list(segs);
|
|
qdisc_skb_cb(segs)->pkt_len = segs->len;
|
|
last_len = segs->len;
|
|
rc = qdisc_enqueue(segs, sch, to_free);
|
|
if (rc != NET_XMIT_SUCCESS) {
|
|
if (net_xmit_drop_count(rc))
|
|
qdisc_qstats_drop(sch);
|
|
} else {
|
|
nb++;
|
|
len += last_len;
|
|
}
|
|
segs = skb2;
|
|
}
|
|
/* Parent qdiscs accounted for 1 skb of size @prev_len */
|
|
qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
|
|
} else if (!skb) {
|
|
return NET_XMIT_DROP;
|
|
}
|
|
return NET_XMIT_SUCCESS;
|
|
}
|
|
|
|
/* Delay the next round with a new future slot with a
|
|
* correct number of bytes and packets.
|
|
*/
|
|
|
|
static void get_slot_next(struct netem_sched_data *q, u64 now)
|
|
{
|
|
s64 next_delay;
|
|
|
|
if (!q->slot_dist)
|
|
next_delay = q->slot_config.min_delay +
|
|
(get_random_u32() *
|
|
(q->slot_config.max_delay -
|
|
q->slot_config.min_delay) >> 32);
|
|
else
|
|
next_delay = tabledist(q->slot_config.dist_delay,
|
|
(s32)(q->slot_config.dist_jitter),
|
|
NULL, q->slot_dist);
|
|
|
|
q->slot.slot_next = now + next_delay;
|
|
q->slot.packets_left = q->slot_config.max_packets;
|
|
q->slot.bytes_left = q->slot_config.max_bytes;
|
|
}
|
|
|
|
static struct sk_buff *netem_peek(struct netem_sched_data *q)
|
|
{
|
|
struct sk_buff *skb = skb_rb_first(&q->t_root);
|
|
u64 t1, t2;
|
|
|
|
if (!skb)
|
|
return q->t_head;
|
|
if (!q->t_head)
|
|
return skb;
|
|
|
|
t1 = netem_skb_cb(skb)->time_to_send;
|
|
t2 = netem_skb_cb(q->t_head)->time_to_send;
|
|
if (t1 < t2)
|
|
return skb;
|
|
return q->t_head;
|
|
}
|
|
|
|
static void netem_erase_head(struct netem_sched_data *q, struct sk_buff *skb)
|
|
{
|
|
if (skb == q->t_head) {
|
|
q->t_head = skb->next;
|
|
if (!q->t_head)
|
|
q->t_tail = NULL;
|
|
} else {
|
|
rb_erase(&skb->rbnode, &q->t_root);
|
|
}
|
|
}
|
|
|
|
static struct sk_buff *netem_dequeue(struct Qdisc *sch)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
struct sk_buff *skb;
|
|
|
|
tfifo_dequeue:
|
|
skb = __qdisc_dequeue_head(&sch->q);
|
|
if (skb) {
|
|
qdisc_qstats_backlog_dec(sch, skb);
|
|
deliver:
|
|
qdisc_bstats_update(sch, skb);
|
|
return skb;
|
|
}
|
|
skb = netem_peek(q);
|
|
if (skb) {
|
|
u64 time_to_send;
|
|
u64 now = ktime_get_ns();
|
|
|
|
/* if more time remaining? */
|
|
time_to_send = netem_skb_cb(skb)->time_to_send;
|
|
if (q->slot.slot_next && q->slot.slot_next < time_to_send)
|
|
get_slot_next(q, now);
|
|
|
|
if (time_to_send <= now && q->slot.slot_next <= now) {
|
|
netem_erase_head(q, skb);
|
|
sch->q.qlen--;
|
|
qdisc_qstats_backlog_dec(sch, skb);
|
|
skb->next = NULL;
|
|
skb->prev = NULL;
|
|
/* skb->dev shares skb->rbnode area,
|
|
* we need to restore its value.
|
|
*/
|
|
skb->dev = qdisc_dev(sch);
|
|
|
|
if (q->slot.slot_next) {
|
|
q->slot.packets_left--;
|
|
q->slot.bytes_left -= qdisc_pkt_len(skb);
|
|
if (q->slot.packets_left <= 0 ||
|
|
q->slot.bytes_left <= 0)
|
|
get_slot_next(q, now);
|
|
}
|
|
|
|
if (q->qdisc) {
|
|
unsigned int pkt_len = qdisc_pkt_len(skb);
|
|
struct sk_buff *to_free = NULL;
|
|
int err;
|
|
|
|
err = qdisc_enqueue(skb, q->qdisc, &to_free);
|
|
kfree_skb_list(to_free);
|
|
if (err != NET_XMIT_SUCCESS &&
|
|
net_xmit_drop_count(err)) {
|
|
qdisc_qstats_drop(sch);
|
|
qdisc_tree_reduce_backlog(sch, 1,
|
|
pkt_len);
|
|
}
|
|
goto tfifo_dequeue;
|
|
}
|
|
goto deliver;
|
|
}
|
|
|
|
if (q->qdisc) {
|
|
skb = q->qdisc->ops->dequeue(q->qdisc);
|
|
if (skb)
|
|
goto deliver;
|
|
}
|
|
|
|
qdisc_watchdog_schedule_ns(&q->watchdog,
|
|
max(time_to_send,
|
|
q->slot.slot_next));
|
|
}
|
|
|
|
if (q->qdisc) {
|
|
skb = q->qdisc->ops->dequeue(q->qdisc);
|
|
if (skb)
|
|
goto deliver;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void netem_reset(struct Qdisc *sch)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
|
|
qdisc_reset_queue(sch);
|
|
tfifo_reset(sch);
|
|
if (q->qdisc)
|
|
qdisc_reset(q->qdisc);
|
|
qdisc_watchdog_cancel(&q->watchdog);
|
|
}
|
|
|
|
static void dist_free(struct disttable *d)
|
|
{
|
|
kvfree(d);
|
|
}
|
|
|
|
/*
|
|
* Distribution data is a variable size payload containing
|
|
* signed 16 bit values.
|
|
*/
|
|
|
|
static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
|
|
const struct nlattr *attr)
|
|
{
|
|
size_t n = nla_len(attr)/sizeof(__s16);
|
|
const __s16 *data = nla_data(attr);
|
|
spinlock_t *root_lock;
|
|
struct disttable *d;
|
|
int i;
|
|
|
|
if (!n || n > NETEM_DIST_MAX)
|
|
return -EINVAL;
|
|
|
|
d = kvmalloc(struct_size(d, table, n), GFP_KERNEL);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
d->size = n;
|
|
for (i = 0; i < n; i++)
|
|
d->table[i] = data[i];
|
|
|
|
root_lock = qdisc_root_sleeping_lock(sch);
|
|
|
|
spin_lock_bh(root_lock);
|
|
swap(*tbl, d);
|
|
spin_unlock_bh(root_lock);
|
|
|
|
dist_free(d);
|
|
return 0;
|
|
}
|
|
|
|
static void get_slot(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct tc_netem_slot *c = nla_data(attr);
|
|
|
|
q->slot_config = *c;
|
|
if (q->slot_config.max_packets == 0)
|
|
q->slot_config.max_packets = INT_MAX;
|
|
if (q->slot_config.max_bytes == 0)
|
|
q->slot_config.max_bytes = INT_MAX;
|
|
|
|
/* capping dist_jitter to the range acceptable by tabledist() */
|
|
q->slot_config.dist_jitter = min_t(__s64, INT_MAX, abs(q->slot_config.dist_jitter));
|
|
|
|
q->slot.packets_left = q->slot_config.max_packets;
|
|
q->slot.bytes_left = q->slot_config.max_bytes;
|
|
if (q->slot_config.min_delay | q->slot_config.max_delay |
|
|
q->slot_config.dist_jitter)
|
|
q->slot.slot_next = ktime_get_ns();
|
|
else
|
|
q->slot.slot_next = 0;
|
|
}
|
|
|
|
static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct tc_netem_corr *c = nla_data(attr);
|
|
|
|
init_crandom(&q->delay_cor, c->delay_corr);
|
|
init_crandom(&q->loss_cor, c->loss_corr);
|
|
init_crandom(&q->dup_cor, c->dup_corr);
|
|
}
|
|
|
|
static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct tc_netem_reorder *r = nla_data(attr);
|
|
|
|
q->reorder = r->probability;
|
|
init_crandom(&q->reorder_cor, r->correlation);
|
|
}
|
|
|
|
static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct tc_netem_corrupt *r = nla_data(attr);
|
|
|
|
q->corrupt = r->probability;
|
|
init_crandom(&q->corrupt_cor, r->correlation);
|
|
}
|
|
|
|
static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct tc_netem_rate *r = nla_data(attr);
|
|
|
|
q->rate = r->rate;
|
|
q->packet_overhead = r->packet_overhead;
|
|
q->cell_size = r->cell_size;
|
|
q->cell_overhead = r->cell_overhead;
|
|
if (q->cell_size)
|
|
q->cell_size_reciprocal = reciprocal_value(q->cell_size);
|
|
else
|
|
q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
|
|
}
|
|
|
|
static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
|
|
{
|
|
const struct nlattr *la;
|
|
int rem;
|
|
|
|
nla_for_each_nested(la, attr, rem) {
|
|
u16 type = nla_type(la);
|
|
|
|
switch (type) {
|
|
case NETEM_LOSS_GI: {
|
|
const struct tc_netem_gimodel *gi = nla_data(la);
|
|
|
|
if (nla_len(la) < sizeof(struct tc_netem_gimodel)) {
|
|
pr_info("netem: incorrect gi model size\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
q->loss_model = CLG_4_STATES;
|
|
|
|
q->clg.state = TX_IN_GAP_PERIOD;
|
|
q->clg.a1 = gi->p13;
|
|
q->clg.a2 = gi->p31;
|
|
q->clg.a3 = gi->p32;
|
|
q->clg.a4 = gi->p14;
|
|
q->clg.a5 = gi->p23;
|
|
break;
|
|
}
|
|
|
|
case NETEM_LOSS_GE: {
|
|
const struct tc_netem_gemodel *ge = nla_data(la);
|
|
|
|
if (nla_len(la) < sizeof(struct tc_netem_gemodel)) {
|
|
pr_info("netem: incorrect ge model size\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
q->loss_model = CLG_GILB_ELL;
|
|
q->clg.state = GOOD_STATE;
|
|
q->clg.a1 = ge->p;
|
|
q->clg.a2 = ge->r;
|
|
q->clg.a3 = ge->h;
|
|
q->clg.a4 = ge->k1;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
pr_info("netem: unknown loss type %u\n", type);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = {
|
|
[TCA_NETEM_CORR] = { .len = sizeof(struct tc_netem_corr) },
|
|
[TCA_NETEM_REORDER] = { .len = sizeof(struct tc_netem_reorder) },
|
|
[TCA_NETEM_CORRUPT] = { .len = sizeof(struct tc_netem_corrupt) },
|
|
[TCA_NETEM_RATE] = { .len = sizeof(struct tc_netem_rate) },
|
|
[TCA_NETEM_LOSS] = { .type = NLA_NESTED },
|
|
[TCA_NETEM_ECN] = { .type = NLA_U32 },
|
|
[TCA_NETEM_RATE64] = { .type = NLA_U64 },
|
|
[TCA_NETEM_LATENCY64] = { .type = NLA_S64 },
|
|
[TCA_NETEM_JITTER64] = { .type = NLA_S64 },
|
|
[TCA_NETEM_SLOT] = { .len = sizeof(struct tc_netem_slot) },
|
|
};
|
|
|
|
static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
|
|
const struct nla_policy *policy, int len)
|
|
{
|
|
int nested_len = nla_len(nla) - NLA_ALIGN(len);
|
|
|
|
if (nested_len < 0) {
|
|
pr_info("netem: invalid attributes len %d\n", nested_len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (nested_len >= nla_attr_size(0))
|
|
return nla_parse_deprecated(tb, maxtype,
|
|
nla_data(nla) + NLA_ALIGN(len),
|
|
nested_len, policy, NULL);
|
|
|
|
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
|
|
return 0;
|
|
}
|
|
|
|
/* Parse netlink message to set options */
|
|
static int netem_change(struct Qdisc *sch, struct nlattr *opt,
|
|
struct netlink_ext_ack *extack)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
struct nlattr *tb[TCA_NETEM_MAX + 1];
|
|
struct tc_netem_qopt *qopt;
|
|
struct clgstate old_clg;
|
|
int old_loss_model = CLG_RANDOM;
|
|
int ret;
|
|
|
|
qopt = nla_data(opt);
|
|
ret = parse_attr(tb, TCA_NETEM_MAX, opt, netem_policy, sizeof(*qopt));
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* backup q->clg and q->loss_model */
|
|
old_clg = q->clg;
|
|
old_loss_model = q->loss_model;
|
|
|
|
if (tb[TCA_NETEM_LOSS]) {
|
|
ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
|
|
if (ret) {
|
|
q->loss_model = old_loss_model;
|
|
return ret;
|
|
}
|
|
} else {
|
|
q->loss_model = CLG_RANDOM;
|
|
}
|
|
|
|
if (tb[TCA_NETEM_DELAY_DIST]) {
|
|
ret = get_dist_table(sch, &q->delay_dist,
|
|
tb[TCA_NETEM_DELAY_DIST]);
|
|
if (ret)
|
|
goto get_table_failure;
|
|
}
|
|
|
|
if (tb[TCA_NETEM_SLOT_DIST]) {
|
|
ret = get_dist_table(sch, &q->slot_dist,
|
|
tb[TCA_NETEM_SLOT_DIST]);
|
|
if (ret)
|
|
goto get_table_failure;
|
|
}
|
|
|
|
sch->limit = qopt->limit;
|
|
|
|
q->latency = PSCHED_TICKS2NS(qopt->latency);
|
|
q->jitter = PSCHED_TICKS2NS(qopt->jitter);
|
|
q->limit = qopt->limit;
|
|
q->gap = qopt->gap;
|
|
q->counter = 0;
|
|
q->loss = qopt->loss;
|
|
q->duplicate = qopt->duplicate;
|
|
|
|
/* for compatibility with earlier versions.
|
|
* if gap is set, need to assume 100% probability
|
|
*/
|
|
if (q->gap)
|
|
q->reorder = ~0;
|
|
|
|
if (tb[TCA_NETEM_CORR])
|
|
get_correlation(q, tb[TCA_NETEM_CORR]);
|
|
|
|
if (tb[TCA_NETEM_REORDER])
|
|
get_reorder(q, tb[TCA_NETEM_REORDER]);
|
|
|
|
if (tb[TCA_NETEM_CORRUPT])
|
|
get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
|
|
|
|
if (tb[TCA_NETEM_RATE])
|
|
get_rate(q, tb[TCA_NETEM_RATE]);
|
|
|
|
if (tb[TCA_NETEM_RATE64])
|
|
q->rate = max_t(u64, q->rate,
|
|
nla_get_u64(tb[TCA_NETEM_RATE64]));
|
|
|
|
if (tb[TCA_NETEM_LATENCY64])
|
|
q->latency = nla_get_s64(tb[TCA_NETEM_LATENCY64]);
|
|
|
|
if (tb[TCA_NETEM_JITTER64])
|
|
q->jitter = nla_get_s64(tb[TCA_NETEM_JITTER64]);
|
|
|
|
if (tb[TCA_NETEM_ECN])
|
|
q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
|
|
|
|
if (tb[TCA_NETEM_SLOT])
|
|
get_slot(q, tb[TCA_NETEM_SLOT]);
|
|
|
|
/* capping jitter to the range acceptable by tabledist() */
|
|
q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
|
|
|
|
return ret;
|
|
|
|
get_table_failure:
|
|
/* recover clg and loss_model, in case of
|
|
* q->clg and q->loss_model were modified
|
|
* in get_loss_clg()
|
|
*/
|
|
q->clg = old_clg;
|
|
q->loss_model = old_loss_model;
|
|
return ret;
|
|
}
|
|
|
|
static int netem_init(struct Qdisc *sch, struct nlattr *opt,
|
|
struct netlink_ext_ack *extack)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
int ret;
|
|
|
|
qdisc_watchdog_init(&q->watchdog, sch);
|
|
|
|
if (!opt)
|
|
return -EINVAL;
|
|
|
|
q->loss_model = CLG_RANDOM;
|
|
ret = netem_change(sch, opt, extack);
|
|
if (ret)
|
|
pr_info("netem: change failed\n");
|
|
return ret;
|
|
}
|
|
|
|
static void netem_destroy(struct Qdisc *sch)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
|
|
qdisc_watchdog_cancel(&q->watchdog);
|
|
if (q->qdisc)
|
|
qdisc_put(q->qdisc);
|
|
dist_free(q->delay_dist);
|
|
dist_free(q->slot_dist);
|
|
}
|
|
|
|
static int dump_loss_model(const struct netem_sched_data *q,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct nlattr *nest;
|
|
|
|
nest = nla_nest_start_noflag(skb, TCA_NETEM_LOSS);
|
|
if (nest == NULL)
|
|
goto nla_put_failure;
|
|
|
|
switch (q->loss_model) {
|
|
case CLG_RANDOM:
|
|
/* legacy loss model */
|
|
nla_nest_cancel(skb, nest);
|
|
return 0; /* no data */
|
|
|
|
case CLG_4_STATES: {
|
|
struct tc_netem_gimodel gi = {
|
|
.p13 = q->clg.a1,
|
|
.p31 = q->clg.a2,
|
|
.p32 = q->clg.a3,
|
|
.p14 = q->clg.a4,
|
|
.p23 = q->clg.a5,
|
|
};
|
|
|
|
if (nla_put(skb, NETEM_LOSS_GI, sizeof(gi), &gi))
|
|
goto nla_put_failure;
|
|
break;
|
|
}
|
|
case CLG_GILB_ELL: {
|
|
struct tc_netem_gemodel ge = {
|
|
.p = q->clg.a1,
|
|
.r = q->clg.a2,
|
|
.h = q->clg.a3,
|
|
.k1 = q->clg.a4,
|
|
};
|
|
|
|
if (nla_put(skb, NETEM_LOSS_GE, sizeof(ge), &ge))
|
|
goto nla_put_failure;
|
|
break;
|
|
}
|
|
}
|
|
|
|
nla_nest_end(skb, nest);
|
|
return 0;
|
|
|
|
nla_put_failure:
|
|
nla_nest_cancel(skb, nest);
|
|
return -1;
|
|
}
|
|
|
|
static int netem_dump(struct Qdisc *sch, struct sk_buff *skb)
|
|
{
|
|
const struct netem_sched_data *q = qdisc_priv(sch);
|
|
struct nlattr *nla = (struct nlattr *) skb_tail_pointer(skb);
|
|
struct tc_netem_qopt qopt;
|
|
struct tc_netem_corr cor;
|
|
struct tc_netem_reorder reorder;
|
|
struct tc_netem_corrupt corrupt;
|
|
struct tc_netem_rate rate;
|
|
struct tc_netem_slot slot;
|
|
|
|
qopt.latency = min_t(psched_time_t, PSCHED_NS2TICKS(q->latency),
|
|
UINT_MAX);
|
|
qopt.jitter = min_t(psched_time_t, PSCHED_NS2TICKS(q->jitter),
|
|
UINT_MAX);
|
|
qopt.limit = q->limit;
|
|
qopt.loss = q->loss;
|
|
qopt.gap = q->gap;
|
|
qopt.duplicate = q->duplicate;
|
|
if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put(skb, TCA_NETEM_LATENCY64, sizeof(q->latency), &q->latency))
|
|
goto nla_put_failure;
|
|
|
|
if (nla_put(skb, TCA_NETEM_JITTER64, sizeof(q->jitter), &q->jitter))
|
|
goto nla_put_failure;
|
|
|
|
cor.delay_corr = q->delay_cor.rho;
|
|
cor.loss_corr = q->loss_cor.rho;
|
|
cor.dup_corr = q->dup_cor.rho;
|
|
if (nla_put(skb, TCA_NETEM_CORR, sizeof(cor), &cor))
|
|
goto nla_put_failure;
|
|
|
|
reorder.probability = q->reorder;
|
|
reorder.correlation = q->reorder_cor.rho;
|
|
if (nla_put(skb, TCA_NETEM_REORDER, sizeof(reorder), &reorder))
|
|
goto nla_put_failure;
|
|
|
|
corrupt.probability = q->corrupt;
|
|
corrupt.correlation = q->corrupt_cor.rho;
|
|
if (nla_put(skb, TCA_NETEM_CORRUPT, sizeof(corrupt), &corrupt))
|
|
goto nla_put_failure;
|
|
|
|
if (q->rate >= (1ULL << 32)) {
|
|
if (nla_put_u64_64bit(skb, TCA_NETEM_RATE64, q->rate,
|
|
TCA_NETEM_PAD))
|
|
goto nla_put_failure;
|
|
rate.rate = ~0U;
|
|
} else {
|
|
rate.rate = q->rate;
|
|
}
|
|
rate.packet_overhead = q->packet_overhead;
|
|
rate.cell_size = q->cell_size;
|
|
rate.cell_overhead = q->cell_overhead;
|
|
if (nla_put(skb, TCA_NETEM_RATE, sizeof(rate), &rate))
|
|
goto nla_put_failure;
|
|
|
|
if (q->ecn && nla_put_u32(skb, TCA_NETEM_ECN, q->ecn))
|
|
goto nla_put_failure;
|
|
|
|
if (dump_loss_model(q, skb) != 0)
|
|
goto nla_put_failure;
|
|
|
|
if (q->slot_config.min_delay | q->slot_config.max_delay |
|
|
q->slot_config.dist_jitter) {
|
|
slot = q->slot_config;
|
|
if (slot.max_packets == INT_MAX)
|
|
slot.max_packets = 0;
|
|
if (slot.max_bytes == INT_MAX)
|
|
slot.max_bytes = 0;
|
|
if (nla_put(skb, TCA_NETEM_SLOT, sizeof(slot), &slot))
|
|
goto nla_put_failure;
|
|
}
|
|
|
|
return nla_nest_end(skb, nla);
|
|
|
|
nla_put_failure:
|
|
nlmsg_trim(skb, nla);
|
|
return -1;
|
|
}
|
|
|
|
static int netem_dump_class(struct Qdisc *sch, unsigned long cl,
|
|
struct sk_buff *skb, struct tcmsg *tcm)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
|
|
if (cl != 1 || !q->qdisc) /* only one class */
|
|
return -ENOENT;
|
|
|
|
tcm->tcm_handle |= TC_H_MIN(1);
|
|
tcm->tcm_info = q->qdisc->handle;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int netem_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
|
|
struct Qdisc **old, struct netlink_ext_ack *extack)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
|
|
*old = qdisc_replace(sch, new, &q->qdisc);
|
|
return 0;
|
|
}
|
|
|
|
static struct Qdisc *netem_leaf(struct Qdisc *sch, unsigned long arg)
|
|
{
|
|
struct netem_sched_data *q = qdisc_priv(sch);
|
|
return q->qdisc;
|
|
}
|
|
|
|
static unsigned long netem_find(struct Qdisc *sch, u32 classid)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
static void netem_walk(struct Qdisc *sch, struct qdisc_walker *walker)
|
|
{
|
|
if (!walker->stop) {
|
|
if (!tc_qdisc_stats_dump(sch, 1, walker))
|
|
return;
|
|
}
|
|
}
|
|
|
|
static const struct Qdisc_class_ops netem_class_ops = {
|
|
.graft = netem_graft,
|
|
.leaf = netem_leaf,
|
|
.find = netem_find,
|
|
.walk = netem_walk,
|
|
.dump = netem_dump_class,
|
|
};
|
|
|
|
static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
|
|
.id = "netem",
|
|
.cl_ops = &netem_class_ops,
|
|
.priv_size = sizeof(struct netem_sched_data),
|
|
.enqueue = netem_enqueue,
|
|
.dequeue = netem_dequeue,
|
|
.peek = qdisc_peek_dequeued,
|
|
.init = netem_init,
|
|
.reset = netem_reset,
|
|
.destroy = netem_destroy,
|
|
.change = netem_change,
|
|
.dump = netem_dump,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
|
|
static int __init netem_module_init(void)
|
|
{
|
|
pr_info("netem: version " VERSION "\n");
|
|
return register_qdisc(&netem_qdisc_ops);
|
|
}
|
|
static void __exit netem_module_exit(void)
|
|
{
|
|
unregister_qdisc(&netem_qdisc_ops);
|
|
}
|
|
module_init(netem_module_init)
|
|
module_exit(netem_module_exit)
|
|
MODULE_LICENSE("GPL");
|