forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
dccp: Policy-based packet dequeueing infrastructure
This patch adds a generic infrastructure for policy-based dequeueing of TX packets and provides two policies: * a simple FIFO policy (which is the default) and * a priority based policy (set via socket options). Both policies honour the tx_qlen sysctl for the maximum size of the write queue (can be overridden via socket options). The priority policy uses skb->priority internally to assign an u32 priority identifier, using the same ranking as SO_PRIORITY. The skb->priority field is set to 0 when the packet leaves DCCP. The priority is supplied as ancillary data using cmsg(3), the patch also provides the requisite parsing routines. Signed-off-by: Tomasz Grobelny <[email protected]> Signed-off-by: Gerrit Renker <[email protected]>
- Loading branch information
Tomasz Grobelny
authored and
Gerrit Renker
committed
Dec 7, 2010
1 parent
cfa969e
commit 871a2c1
Showing
7 changed files
with
248 additions
and
9 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,126 @@ | ||
| /* | ||
| * net/dccp/qpolicy.c | ||
| * | ||
| * Policy-based packet dequeueing interface for DCCP. | ||
| * | ||
| * Copyright (c) 2008 Tomasz Grobelny <[email protected]> | ||
| * | ||
| * 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. | ||
| */ | ||
| #include "dccp.h" | ||
|
|
||
| /* | ||
| * Simple Dequeueing Policy: | ||
| * If tx_qlen is different from 0, enqueue up to tx_qlen elements. | ||
| */ | ||
| static void qpolicy_simple_push(struct sock *sk, struct sk_buff *skb) | ||
| { | ||
| skb_queue_tail(&sk->sk_write_queue, skb); | ||
| } | ||
|
|
||
| static bool qpolicy_simple_full(struct sock *sk) | ||
| { | ||
| return dccp_sk(sk)->dccps_tx_qlen && | ||
| sk->sk_write_queue.qlen >= dccp_sk(sk)->dccps_tx_qlen; | ||
| } | ||
|
|
||
| static struct sk_buff *qpolicy_simple_top(struct sock *sk) | ||
| { | ||
| return skb_peek(&sk->sk_write_queue); | ||
| } | ||
|
|
||
| /* | ||
| * Priority-based Dequeueing Policy: | ||
| * If tx_qlen is different from 0 and the queue has reached its upper bound | ||
| * of tx_qlen elements, replace older packets lowest-priority-first. | ||
| */ | ||
| static struct sk_buff *qpolicy_prio_best_skb(struct sock *sk) | ||
| { | ||
| struct sk_buff *skb, *best = NULL; | ||
|
|
||
| skb_queue_walk(&sk->sk_write_queue, skb) | ||
| if (best == NULL || skb->priority > best->priority) | ||
| best = skb; | ||
| return best; | ||
| } | ||
|
|
||
| static struct sk_buff *qpolicy_prio_worst_skb(struct sock *sk) | ||
| { | ||
| struct sk_buff *skb, *worst = NULL; | ||
|
|
||
| skb_queue_walk(&sk->sk_write_queue, skb) | ||
| if (worst == NULL || skb->priority < worst->priority) | ||
| worst = skb; | ||
| return worst; | ||
| } | ||
|
|
||
| static bool qpolicy_prio_full(struct sock *sk) | ||
| { | ||
| if (qpolicy_simple_full(sk)) | ||
| dccp_qpolicy_drop(sk, qpolicy_prio_worst_skb(sk)); | ||
| return false; | ||
| } | ||
|
|
||
| /** | ||
| * struct dccp_qpolicy_operations - TX Packet Dequeueing Interface | ||
| * @push: add a new @skb to the write queue | ||
| * @full: indicates that no more packets will be admitted | ||
| * @top: peeks at whatever the queueing policy defines as its `top' | ||
| */ | ||
| static struct dccp_qpolicy_operations { | ||
| void (*push) (struct sock *sk, struct sk_buff *skb); | ||
| bool (*full) (struct sock *sk); | ||
| struct sk_buff* (*top) (struct sock *sk); | ||
|
|
||
| } qpol_table[DCCPQ_POLICY_MAX] = { | ||
| [DCCPQ_POLICY_SIMPLE] = { | ||
| .push = qpolicy_simple_push, | ||
| .full = qpolicy_simple_full, | ||
| .top = qpolicy_simple_top, | ||
| }, | ||
| [DCCPQ_POLICY_PRIO] = { | ||
| .push = qpolicy_simple_push, | ||
| .full = qpolicy_prio_full, | ||
| .top = qpolicy_prio_best_skb, | ||
| }, | ||
| }; | ||
|
|
||
| /* | ||
| * Externally visible interface | ||
| */ | ||
| void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb) | ||
| { | ||
| qpol_table[dccp_sk(sk)->dccps_qpolicy].push(sk, skb); | ||
| } | ||
|
|
||
| bool dccp_qpolicy_full(struct sock *sk) | ||
| { | ||
| return qpol_table[dccp_sk(sk)->dccps_qpolicy].full(sk); | ||
| } | ||
|
|
||
| void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb) | ||
| { | ||
| if (skb != NULL) { | ||
| skb_unlink(skb, &sk->sk_write_queue); | ||
| kfree_skb(skb); | ||
| } | ||
| } | ||
|
|
||
| struct sk_buff *dccp_qpolicy_top(struct sock *sk) | ||
| { | ||
| return qpol_table[dccp_sk(sk)->dccps_qpolicy].top(sk); | ||
| } | ||
|
|
||
| struct sk_buff *dccp_qpolicy_pop(struct sock *sk) | ||
| { | ||
| struct sk_buff *skb = dccp_qpolicy_top(sk); | ||
|
|
||
| if (skb != NULL) { | ||
| /* Clear any skb fields that we used internally */ | ||
| skb->priority = 0; | ||
| skb_unlink(skb, &sk->sk_write_queue); | ||
| } | ||
| return skb; | ||
| } |