From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: [PATCH net-next 6/7] net: Add flow_keys digest Date: Tue, 28 Apr 2015 21:27:40 -0700 Message-ID: <1430281661-2271966-7-git-send-email-tom@herbertland.com> References: <1430281661-2271966-1-git-send-email-tom@herbertland.com> Mime-Version: 1.0 Content-Type: text/plain Cc: To: , Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:39868 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751518AbbD2E2R (ORCPT ); Wed, 29 Apr 2015 00:28:17 -0400 Received: from pps.filterd (m0044008 [127.0.0.1]) by mx0a-00082601.pphosted.com (8.14.5/8.14.5) with SMTP id t3T4R4im021998 for ; Tue, 28 Apr 2015 21:28:16 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 1u2pxcr470-1 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Tue, 28 Apr 2015 21:28:16 -0700 Received: from facebook.com (2401:db00:20:702e:face:0:23:0) by mx-out.facebook.com (10.212.232.63) with ESMTP id 274912b2ee2811e4afb00002c992ebde-377d02c0 for ; Tue, 28 Apr 2015 21:28:15 -0700 In-Reply-To: <1430281661-2271966-1-git-send-email-tom@herbertland.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h index dc8fd81..f2610ad 100644 --- a/include/net/flow_keys.h +++ b/include/net/flow_keys.h @@ -42,4 +42,23 @@ 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 used to hold a digest of the full flow keys. This is a larger + * "hash" of a connection 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]; +}; + +static inline void make_flow_keys_digest(struct flow_keys_digest *digest, + struct flow_keys *flow) +{ + memcpy(&digest->data, flow, FLOW_KEYS_DIGEST_LEN); +} + #endif -- 1.8.1