From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: [PATCH net-next v2 2/3] net: Add inet_proto_csum_replace_by_diff utility function Date: Mon, 17 Aug 2015 09:56:50 -0700 Message-ID: <1439830611-22898-3-git-send-email-tom@herbertland.com> References: <1439830611-22898-1-git-send-email-tom@herbertland.com> Mime-Version: 1.0 Content-Type: text/plain Cc: To: , Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:36185 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753651AbbHQQ6p (ORCPT ); Mon, 17 Aug 2015 12:58:45 -0400 Received: from pps.filterd (m0004077 [127.0.0.1]) by mx0b-00082601.pphosted.com (8.14.5/8.14.5) with SMTP id t7HGwZNL005727 for ; Mon, 17 Aug 2015 09:58:45 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 1wbefq1crq-6 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Mon, 17 Aug 2015 09:58:45 -0700 Received: from facebook.com (2401:db00:20:702e:face:0:23:0) by mx-out.facebook.com (10.103.99.97) with ESMTP id 31d84e70450111e5b2bd0002c9931860-1bbf52b0 for ; Mon, 17 Aug 2015 09:58:33 -0700 In-Reply-To: <1439830611-22898-1-git-send-email-tom@herbertland.com> Sender: netdev-owner@vger.kernel.org List-ID: This function updates a checksum field value and skb->csum based on a value which is the difference between the old and new checksum. Signed-off-by: Tom Herbert --- include/net/checksum.h | 2 ++ net/core/utils.c | 13 +++++++++++++ 2 files changed, 15 insertions(+) diff --git a/include/net/checksum.h b/include/net/checksum.h index 2d1d73c..0e0c987 100644 --- a/include/net/checksum.h +++ b/include/net/checksum.h @@ -144,6 +144,8 @@ void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, const __be32 *from, const __be32 *to, int pseudohdr); +void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, + __wsum diff, int pseudohdr); static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, __be16 from, __be16 to, diff --git a/net/core/utils.c b/net/core/utils.c index a7732a0..89ccfb1 100644 --- a/net/core/utils.c +++ b/net/core/utils.c @@ -336,6 +336,19 @@ void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, } EXPORT_SYMBOL(inet_proto_csum_replace16); +void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, + __wsum diff, int pseudohdr) +{ + if (skb->ip_summed != CHECKSUM_PARTIAL) { + *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum))); + if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr) + skb->csum = ~csum_add(diff, ~skb->csum); + } else if (pseudohdr) { + *sum = ~csum_fold(csum_add(diff, csum_unfold(*sum))); + } +} +EXPORT_SYMBOL(inet_proto_csum_replace_by_diff); + struct __net_random_once_work { struct work_struct work; struct static_key *key; -- 1.8.1