From patchwork Sat Oct 11 07:31:20 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerrit Renker X-Patchwork-Id: 3979 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 26DA9DDE08 for ; Sat, 11 Oct 2008 18:31:32 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751580AbYJKHba (ORCPT ); Sat, 11 Oct 2008 03:31:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751769AbYJKHba (ORCPT ); Sat, 11 Oct 2008 03:31:30 -0400 Received: from dee.erg.abdn.ac.uk ([139.133.204.82]:38975 "EHLO erg.abdn.ac.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751580AbYJKHb2 (ORCPT ); Sat, 11 Oct 2008 03:31:28 -0400 Received: from laptev.erg.abdn.ac.uk (Debian-exim@ra-gerrit.erg.abdn.ac.uk [139.133.204.38]) by erg.abdn.ac.uk (8.13.4/8.13.4) with ESMTP id m9B7VKAh012812 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Sat, 11 Oct 2008 08:31:20 +0100 (BST) Received: from gerrit by laptev.erg.abdn.ac.uk with local (Exim 4.69) (envelope-from ) id 1KoYwa-0002Rv-Az; Sat, 11 Oct 2008 09:31:20 +0200 Date: Sat, 11 Oct 2008 09:31:20 +0200 From: Gerrit Renker To: "David S. Miller" , netdev@vger.kernel.org, dccp@vger.kernel.org Subject: [PATCH 1/5] dccp: Basic data structure for feature negotiation Message-ID: <20081011073120.GB9205@gerrit.erg.abdn.ac.uk> Mail-Followup-To: Gerrit Renker , "David S. Miller" , netdev@vger.kernel.org, dccp@vger.kernel.org References: <20081005.091334.208715265.davem@davemloft.net> <1223312049-25967-1-git-send-email-gerrit@erg.abdn.ac.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1223312049-25967-1-git-send-email-gerrit@erg.abdn.ac.uk> Received: from laptev.erg.abdn.ac.uk (Debian-exim@ra-gerrit.erg.abdn.ac.uk [139.133.204.38]) by erg.abdn.ac.uk (8.13.4/8.13.4) with ESMTP id m96Gs9lk003394 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Mon, 6 Oct 2008 17:54:09 +0100 (BST) Received: from root by laptev.erg.abdn.ac.uk with local (Exim 4.69) (envelope-from ) id 1KmtLV-0006lJ-Vp for gerrit@erg.abdn.ac.uk; Mon, 06 Oct 2008 18:54:09 +0200 X-Mailer: git-send-email 1.6.0.rc2 X-ERG-MailScanner: Found to be clean, Found to be clean X-Spam-Status: No, No X-UIDL: iUJ!!#G&"!?AR!!1/"!! User-Agent: Mutt/1.5.18 (2008-05-17) X-ERG-MailScanner-From: gerrit@erg.abdn.ac.uk Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch prepares for the new and extended feature-negotiation routines. The following feature-negotiation data structures are provided: * a container for the various (SP or NN) values, * symbolic state names to track feature states, * an entry struct which holds all current information together, * elementary functions to fill in and process these structures. Entry structs are arranged as FIFO for the following reason: RFC 4340 specifies that if multiple options of the same type are present, they are processed in the order of their appearance in the packet; which means that this order needs to be preserved in the local data structure (the later insertion code also respects this order). The struct list_head has been chosen for the following reasons: the most frequent operations are * add new entry at tail (when receiving Change or setting socket options); * delete entry (when Confirm has been received); * deep copy of entire list (cloning from listening socket onto request socket). The NN value has been set to 64 bit, which is a currently sufficient upper limit (Sequence Window feature has 48 bit). Thanks to Arnaldo, who contributed the streamlined layout of the entry struct. Signed-off-by: Gerrit Renker Acked-by: Arnaldo Carvalho de Melo --- net/dccp/feat.h | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 61 insertions(+), 0 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/net/dccp/feat.h +++ b/net/dccp/feat.h @@ -14,6 +14,67 @@ #include #include "dccp.h" +enum dccp_feat_type { + FEAT_AT_RX = 1, /* located at RX side of half-connection */ + FEAT_AT_TX = 2, /* located at TX side of half-connection */ + FEAT_SP = 4, /* server-priority reconciliation (6.3.1) */ + FEAT_NN = 8, /* non-negotiable reconciliation (6.3.2) */ + FEAT_UNKNOWN = 0xFF /* not understood or invalid feature */ +}; + +enum dccp_feat_state { + FEAT_DEFAULT = 0, /* using default values from 6.4 */ + FEAT_INITIALISING, /* feature is being initialised */ + FEAT_CHANGING, /* Change sent but not confirmed yet */ + FEAT_UNSTABLE, /* local modification in state CHANGING */ + FEAT_STABLE /* both ends (think they) agree */ +}; + +/** + * dccp_feat_val - Container for SP or NN feature values + * @nn: single NN value + * @sp.vec: single SP value plus optional preference list + * @sp.len: length of @sp.vec in bytes + */ +typedef union { + u64 nn; + struct { + u8 *vec; + u8 len; + } sp; +} dccp_feat_val; + +/** + * struct feat_entry - Data structure to perform feature negotiation + * @val: feature's current value (SP features may have preference list) + * @state: feature's current state + * @feat_num: one of %dccp_feature_numbers + * @needs_mandatory: whether Mandatory options should be sent + * @needs_confirm: whether to send a Confirm instead of a Change + * @empty_confirm: whether to send an empty Confirm (depends on @needs_confirm) + * @is_local: feature location (1) or feature-remote (0) + * @node: list pointers, entries arranged in FIFO order + */ +struct dccp_feat_entry { + dccp_feat_val val; + enum dccp_feat_state state:8; + u8 feat_num; + + bool needs_mandatory, + needs_confirm, + empty_confirm, + is_local; + + struct list_head node; +}; + +static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry) +{ + if (entry->needs_confirm) + return entry->is_local ? DCCPO_CONFIRM_L : DCCPO_CONFIRM_R; + return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R; +} + #ifdef CONFIG_IP_DCCP_DEBUG extern const char *dccp_feat_typename(const u8 type); extern const char *dccp_feat_name(const u8 feat);