e46bd7099d
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license v2 as published by the free software foundation extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531081037.837563564@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/dccp/qpolicy.c
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*
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* Policy-based packet dequeueing interface for DCCP.
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*
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* Copyright (c) 2008 Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>
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*/
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#include "dccp.h"
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/*
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* Simple Dequeueing Policy:
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* If tx_qlen is different from 0, enqueue up to tx_qlen elements.
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*/
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static void qpolicy_simple_push(struct sock *sk, struct sk_buff *skb)
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{
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skb_queue_tail(&sk->sk_write_queue, skb);
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}
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static bool qpolicy_simple_full(struct sock *sk)
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{
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return dccp_sk(sk)->dccps_tx_qlen &&
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sk->sk_write_queue.qlen >= dccp_sk(sk)->dccps_tx_qlen;
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}
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static struct sk_buff *qpolicy_simple_top(struct sock *sk)
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{
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return skb_peek(&sk->sk_write_queue);
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}
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/*
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* Priority-based Dequeueing Policy:
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* If tx_qlen is different from 0 and the queue has reached its upper bound
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* of tx_qlen elements, replace older packets lowest-priority-first.
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*/
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static struct sk_buff *qpolicy_prio_best_skb(struct sock *sk)
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{
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struct sk_buff *skb, *best = NULL;
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skb_queue_walk(&sk->sk_write_queue, skb)
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if (best == NULL || skb->priority > best->priority)
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best = skb;
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return best;
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}
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static struct sk_buff *qpolicy_prio_worst_skb(struct sock *sk)
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{
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struct sk_buff *skb, *worst = NULL;
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skb_queue_walk(&sk->sk_write_queue, skb)
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if (worst == NULL || skb->priority < worst->priority)
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worst = skb;
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return worst;
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}
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static bool qpolicy_prio_full(struct sock *sk)
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{
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if (qpolicy_simple_full(sk))
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dccp_qpolicy_drop(sk, qpolicy_prio_worst_skb(sk));
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return false;
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}
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/**
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* struct dccp_qpolicy_operations - TX Packet Dequeueing Interface
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* @push: add a new @skb to the write queue
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* @full: indicates that no more packets will be admitted
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* @top: peeks at whatever the queueing policy defines as its `top'
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*/
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static struct dccp_qpolicy_operations {
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void (*push) (struct sock *sk, struct sk_buff *skb);
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bool (*full) (struct sock *sk);
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struct sk_buff* (*top) (struct sock *sk);
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__be32 params;
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} qpol_table[DCCPQ_POLICY_MAX] = {
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[DCCPQ_POLICY_SIMPLE] = {
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.push = qpolicy_simple_push,
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.full = qpolicy_simple_full,
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.top = qpolicy_simple_top,
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.params = 0,
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},
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[DCCPQ_POLICY_PRIO] = {
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.push = qpolicy_simple_push,
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.full = qpolicy_prio_full,
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.top = qpolicy_prio_best_skb,
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.params = DCCP_SCM_PRIORITY,
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},
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};
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/*
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* Externally visible interface
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*/
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void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb)
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{
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qpol_table[dccp_sk(sk)->dccps_qpolicy].push(sk, skb);
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}
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bool dccp_qpolicy_full(struct sock *sk)
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{
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return qpol_table[dccp_sk(sk)->dccps_qpolicy].full(sk);
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}
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void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb)
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{
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if (skb != NULL) {
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skb_unlink(skb, &sk->sk_write_queue);
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kfree_skb(skb);
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}
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}
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struct sk_buff *dccp_qpolicy_top(struct sock *sk)
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{
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return qpol_table[dccp_sk(sk)->dccps_qpolicy].top(sk);
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}
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struct sk_buff *dccp_qpolicy_pop(struct sock *sk)
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{
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struct sk_buff *skb = dccp_qpolicy_top(sk);
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if (skb != NULL) {
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/* Clear any skb fields that we used internally */
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skb->priority = 0;
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skb_unlink(skb, &sk->sk_write_queue);
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}
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return skb;
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}
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bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param)
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{
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/* check if exactly one bit is set */
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if (!param || (param & (param - 1)))
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return false;
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return (qpol_table[dccp_sk(sk)->dccps_qpolicy].params & param) == param;
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}
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