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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * net/dccp/qpolicy.c
4 *
5 * Policy-based packet dequeueing interface for DCCP.
6 *
7 * Copyright (c) 2008 Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>
8 */
9#include "dccp.h"
10
11/*
12 * Simple Dequeueing Policy:
13 * If tx_qlen is different from 0, enqueue up to tx_qlen elements.
14 */
15static void qpolicy_simple_push(struct sock *sk, struct sk_buff *skb)
16{
17 skb_queue_tail(&sk->sk_write_queue, skb);
18}
19
20static bool qpolicy_simple_full(struct sock *sk)
21{
22 return dccp_sk(sk)->dccps_tx_qlen &&
23 sk->sk_write_queue.qlen >= dccp_sk(sk)->dccps_tx_qlen;
24}
25
26static struct sk_buff *qpolicy_simple_top(struct sock *sk)
27{
28 return skb_peek(&sk->sk_write_queue);
29}
30
31/*
32 * Priority-based Dequeueing Policy:
33 * If tx_qlen is different from 0 and the queue has reached its upper bound
34 * of tx_qlen elements, replace older packets lowest-priority-first.
35 */
36static struct sk_buff *qpolicy_prio_best_skb(struct sock *sk)
37{
38 struct sk_buff *skb, *best = NULL;
39
40 skb_queue_walk(&sk->sk_write_queue, skb)
41 if (best == NULL || skb->priority > best->priority)
42 best = skb;
43 return best;
44}
45
46static struct sk_buff *qpolicy_prio_worst_skb(struct sock *sk)
47{
48 struct sk_buff *skb, *worst = NULL;
49
50 skb_queue_walk(&sk->sk_write_queue, skb)
51 if (worst == NULL || skb->priority < worst->priority)
52 worst = skb;
53 return worst;
54}
55
56static bool qpolicy_prio_full(struct sock *sk)
57{
58 if (qpolicy_simple_full(sk))
59 dccp_qpolicy_drop(sk, qpolicy_prio_worst_skb(sk));
60 return false;
61}
62
63/**
64 * struct dccp_qpolicy_operations - TX Packet Dequeueing Interface
65 * @push: add a new @skb to the write queue
66 * @full: indicates that no more packets will be admitted
67 * @top: peeks at whatever the queueing policy defines as its `top'
68 * @params: parameter passed to policy operation
69 */
70struct dccp_qpolicy_operations {
71 void (*push) (struct sock *sk, struct sk_buff *skb);
72 bool (*full) (struct sock *sk);
73 struct sk_buff* (*top) (struct sock *sk);
74 __be32 params;
75};
76
77static struct dccp_qpolicy_operations qpol_table[DCCPQ_POLICY_MAX] = {
78 [DCCPQ_POLICY_SIMPLE] = {
79 .push = qpolicy_simple_push,
80 .full = qpolicy_simple_full,
81 .top = qpolicy_simple_top,
82 .params = 0,
83 },
84 [DCCPQ_POLICY_PRIO] = {
85 .push = qpolicy_simple_push,
86 .full = qpolicy_prio_full,
87 .top = qpolicy_prio_best_skb,
88 .params = DCCP_SCM_PRIORITY,
89 },
90};
91
92/*
93 * Externally visible interface
94 */
95void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb)
96{
97 qpol_table[dccp_sk(sk)->dccps_qpolicy].push(sk, skb);
98}
99
100bool dccp_qpolicy_full(struct sock *sk)
101{
102 return qpol_table[dccp_sk(sk)->dccps_qpolicy].full(sk);
103}
104
105void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb)
106{
107 if (skb != NULL) {
108 skb_unlink(skb, &sk->sk_write_queue);
109 kfree_skb(skb);
110 }
111}
112
113struct sk_buff *dccp_qpolicy_top(struct sock *sk)
114{
115 return qpol_table[dccp_sk(sk)->dccps_qpolicy].top(sk);
116}
117
118struct sk_buff *dccp_qpolicy_pop(struct sock *sk)
119{
120 struct sk_buff *skb = dccp_qpolicy_top(sk);
121
122 if (skb != NULL) {
123 /* Clear any skb fields that we used internally */
124 skb->priority = 0;
125 skb_unlink(skb, &sk->sk_write_queue);
126 }
127 return skb;
128}
129
130bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param)
131{
132 /* check if exactly one bit is set */
133 if (!param || (param & (param - 1)))
134 return false;
135 return (qpol_table[dccp_sk(sk)->dccps_qpolicy].params & param) == param;
136}
1/*
2 * net/dccp/qpolicy.c
3 *
4 * Policy-based packet dequeueing interface for DCCP.
5 *
6 * Copyright (c) 2008 Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License v2
10 * as published by the Free Software Foundation.
11 */
12#include "dccp.h"
13
14/*
15 * Simple Dequeueing Policy:
16 * If tx_qlen is different from 0, enqueue up to tx_qlen elements.
17 */
18static void qpolicy_simple_push(struct sock *sk, struct sk_buff *skb)
19{
20 skb_queue_tail(&sk->sk_write_queue, skb);
21}
22
23static bool qpolicy_simple_full(struct sock *sk)
24{
25 return dccp_sk(sk)->dccps_tx_qlen &&
26 sk->sk_write_queue.qlen >= dccp_sk(sk)->dccps_tx_qlen;
27}
28
29static struct sk_buff *qpolicy_simple_top(struct sock *sk)
30{
31 return skb_peek(&sk->sk_write_queue);
32}
33
34/*
35 * Priority-based Dequeueing Policy:
36 * If tx_qlen is different from 0 and the queue has reached its upper bound
37 * of tx_qlen elements, replace older packets lowest-priority-first.
38 */
39static struct sk_buff *qpolicy_prio_best_skb(struct sock *sk)
40{
41 struct sk_buff *skb, *best = NULL;
42
43 skb_queue_walk(&sk->sk_write_queue, skb)
44 if (best == NULL || skb->priority > best->priority)
45 best = skb;
46 return best;
47}
48
49static struct sk_buff *qpolicy_prio_worst_skb(struct sock *sk)
50{
51 struct sk_buff *skb, *worst = NULL;
52
53 skb_queue_walk(&sk->sk_write_queue, skb)
54 if (worst == NULL || skb->priority < worst->priority)
55 worst = skb;
56 return worst;
57}
58
59static bool qpolicy_prio_full(struct sock *sk)
60{
61 if (qpolicy_simple_full(sk))
62 dccp_qpolicy_drop(sk, qpolicy_prio_worst_skb(sk));
63 return false;
64}
65
66/**
67 * struct dccp_qpolicy_operations - TX Packet Dequeueing Interface
68 * @push: add a new @skb to the write queue
69 * @full: indicates that no more packets will be admitted
70 * @top: peeks at whatever the queueing policy defines as its `top'
71 */
72static struct dccp_qpolicy_operations {
73 void (*push) (struct sock *sk, struct sk_buff *skb);
74 bool (*full) (struct sock *sk);
75 struct sk_buff* (*top) (struct sock *sk);
76 __be32 params;
77
78} qpol_table[DCCPQ_POLICY_MAX] = {
79 [DCCPQ_POLICY_SIMPLE] = {
80 .push = qpolicy_simple_push,
81 .full = qpolicy_simple_full,
82 .top = qpolicy_simple_top,
83 .params = 0,
84 },
85 [DCCPQ_POLICY_PRIO] = {
86 .push = qpolicy_simple_push,
87 .full = qpolicy_prio_full,
88 .top = qpolicy_prio_best_skb,
89 .params = DCCP_SCM_PRIORITY,
90 },
91};
92
93/*
94 * Externally visible interface
95 */
96void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb)
97{
98 qpol_table[dccp_sk(sk)->dccps_qpolicy].push(sk, skb);
99}
100
101bool dccp_qpolicy_full(struct sock *sk)
102{
103 return qpol_table[dccp_sk(sk)->dccps_qpolicy].full(sk);
104}
105
106void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb)
107{
108 if (skb != NULL) {
109 skb_unlink(skb, &sk->sk_write_queue);
110 kfree_skb(skb);
111 }
112}
113
114struct sk_buff *dccp_qpolicy_top(struct sock *sk)
115{
116 return qpol_table[dccp_sk(sk)->dccps_qpolicy].top(sk);
117}
118
119struct sk_buff *dccp_qpolicy_pop(struct sock *sk)
120{
121 struct sk_buff *skb = dccp_qpolicy_top(sk);
122
123 if (skb != NULL) {
124 /* Clear any skb fields that we used internally */
125 skb->priority = 0;
126 skb_unlink(skb, &sk->sk_write_queue);
127 }
128 return skb;
129}
130
131bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param)
132{
133 /* check if exactly one bit is set */
134 if (!param || (param & (param - 1)))
135 return false;
136 return (qpol_table[dccp_sk(sk)->dccps_qpolicy].params & param) == param;
137}