From patchwork Fri May 1 18:30:17 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Herbert X-Patchwork-Id: 467084 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 [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id DB9961402B2 for ; Sat, 2 May 2015 04:30:58 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751908AbbEASaz (ORCPT ); Fri, 1 May 2015 14:30:55 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:27554 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751873AbbEASao (ORCPT ); Fri, 1 May 2015 14:30:44 -0400 Received: from pps.filterd (m0004077 [127.0.0.1]) by mx0b-00082601.pphosted.com (8.14.5/8.14.5) with SMTP id t41IRgwM016506 for ; Fri, 1 May 2015 11:30:43 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 1u4e72861d-1 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Fri, 01 May 2015 11:30:43 -0700 Received: from mx-out.facebook.com (192.168.52.13) by PRN-CHUB02.TheFacebook.com (192.168.16.12) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 1 May 2015 11:30:42 -0700 Received: from facebook.com (2401:db00:20:702e:face:0:23:0) by mx-out.facebook.com (10.212.236.89) with ESMTP id 2c30a4d4f03011e484500002c95209d8-7cad8240 for ; Fri, 01 May 2015 11:30:41 -0700 Received: by devrs030.prn2.facebook.com (Postfix, from userid 12345) id 763A1A8002D; Fri, 1 May 2015 11:30:41 -0700 (PDT) From: Tom Herbert To: , Subject: [PATCH v2 net-next 6/7] net: Add flow_keys digest Date: Fri, 1 May 2015 11:30:17 -0700 Message-ID: <1430505018-496801-7-git-send-email-tom@herbertland.com> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1430505018-496801-1-git-send-email-tom@herbertland.com> References: <1430505018-496801-1-git-send-email-tom@herbertland.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.13.68, 1.0.33, 0.0.0000 definitions=2015-05-01_07:2015-05-01, 2015-05-01, 1970-01-01 signatures=0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Some users of flow keys (well just sch_choke now) need to pass flow_keys in skbuff cb, and use them for exact comparisons of flows so that skb->hash is not sufficient. In order to increase size of the flow_keys structure, we introduce another structure for the purpose of passing flow keys in skbuff cb. We limit this structure to sixteen bytes, and we will technically treat this as a digest of flow_keys struct hence its name flow_keys_digest. In the first incaranation we just copy the flow_keys structure up to 16 bytes-- this is the same information previously passed in the cb. In the future, we'll adapt this for larger flow_keys and could use something like SHA-1 over the whole flow_keys to improve the quality of the digest. Signed-off-by: Tom Herbert --- include/net/flow_keys.h | 16 ++++++++++++++++ net/core/flow_dissector.c | 27 +++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h index dc8fd81..6d6ef62 100644 --- a/include/net/flow_keys.h +++ b/include/net/flow_keys.h @@ -42,4 +42,20 @@ static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 u32 flow_hash_from_keys(struct flow_keys *keys); unsigned int flow_get_hlen(const unsigned char *data, unsigned int max_len, __be16 protocol); + +/* struct flow_keys_digest: + * + * This structure is used to hold a digest of the full flow keys. This is a + * larger "hash" of a flow to allow definitively matching specific flows where + * the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so + * that it can by used in CB of skb (see sch_choke for an example). + */ +#define FLOW_KEYS_DIGEST_LEN 16 +struct flow_keys_digest { + u8 data[FLOW_KEYS_DIGEST_LEN]; +}; + +void make_flow_keys_digest(struct flow_keys_digest *digest, + const struct flow_keys *flow); + #endif diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index b1df995..d3acc4d 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -310,6 +310,33 @@ static inline u32 ___skb_get_hash(const struct sk_buff *skb, return __flow_hash_from_keys(keys, keyval); } +struct _flow_keys_digest_data { + __be16 n_proto; + u8 ip_proto; + u8 padding; + __be32 ports; + __be32 src; + __be32 dst; +}; + +void make_flow_keys_digest(struct flow_keys_digest *digest, + const struct flow_keys *flow) +{ + struct _flow_keys_digest_data *data = + (struct _flow_keys_digest_data *)digest; + + BUILD_BUG_ON(sizeof(*data) > sizeof(*digest)); + + memset(digest, 0, sizeof(*digest)); + + data->n_proto = flow->n_proto; + data->ip_proto = flow->ip_proto; + data->ports = flow->ports; + data->src = flow->src; + data->dst = flow->dst; +} +EXPORT_SYMBOL(make_flow_keys_digest); + /* * __skb_get_hash: calculate a flow hash based on src/dst addresses * and src/dst port numbers. Sets hash in skb to non-zero hash value