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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 03/29] netfilter: nf_dup4: remove redundant checksum recalculation
Date: Mon,  5 Sep 2016 12:58:18 +0200	[thread overview]
Message-ID: <1473073124-5015-4-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1473073124-5015-1-git-send-email-pablo@netfilter.org>

From: Liping Zhang <liping.zhang@spreadtrum.com>

IP header checksum will be recalculated at ip_local_out, so
there's no need to calculated it here, remove it. Also update
code comments to illustrate it, and delete the misleading
comments about checksum recalculation.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv4/netfilter/nf_dup_ipv4.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/netfilter/nf_dup_ipv4.c b/net/ipv4/netfilter/nf_dup_ipv4.c
index ceb1873..cf986e1 100644
--- a/net/ipv4/netfilter/nf_dup_ipv4.c
+++ b/net/ipv4/netfilter/nf_dup_ipv4.c
@@ -74,21 +74,19 @@ void nf_dup_ipv4(struct net *net, struct sk_buff *skb, unsigned int hooknum,
 	nf_conntrack_get(skb->nfct);
 #endif
 	/*
-	 * If we are in PREROUTING/INPUT, the checksum must be recalculated
-	 * since the length could have changed as a result of defragmentation.
-	 *
-	 * We also decrease the TTL to mitigate potential loops between two
-	 * hosts.
+	 * If we are in PREROUTING/INPUT, decrease the TTL to mitigate potential
+	 * loops between two hosts.
 	 *
 	 * Set %IP_DF so that the original source is notified of a potentially
 	 * decreased MTU on the clone route. IPv6 does this too.
+	 *
+	 * IP header checksum will be recalculated at ip_local_out.
 	 */
 	iph = ip_hdr(skb);
 	iph->frag_off |= htons(IP_DF);
 	if (hooknum == NF_INET_PRE_ROUTING ||
 	    hooknum == NF_INET_LOCAL_IN)
 		--iph->ttl;
-	ip_send_check(iph);
 
 	if (nf_dup_ipv4_route(net, skb, gw, oif)) {
 		__this_cpu_write(nf_skb_duplicated, true);
-- 
2.1.4


  parent reply	other threads:[~2016-09-05 10:58 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-05 10:58 [PATCH 00/29] Netfilter updates for net-next Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 01/29] netfilter: conntrack: Only need first 4 bytes to get l4proto ports Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 02/29] netfilter: physdev: add missed blank Pablo Neira Ayuso
2016-09-05 17:43   ` Joe Perches
2016-09-05 10:58 ` Pablo Neira Ayuso [this message]
2016-09-05 10:58 ` [PATCH 04/29] netfilter: use_nf_conn_expires helper in more places Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 05/29] ipvs: use nf_ct_kill helper Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 06/29] netfilter: nf_tables: rename set implementations Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 07/29] netfilter: nf_tables: add hash expression Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 08/29] netfilter: remove ip_conntrack* sysctl compat code Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 09/29] netfilter: conntrack: simplify the code by using nf_conntrack_get_ht Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 10/29] netfilter: nf_conntrack: restore nf_conntrack_htable_size as exported symbol Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 11/29] netfilter: nf_tables: add quota expression Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 12/29] netfilter: nf_tables: add number generator expression Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 13/29] netfilter: fix spelling mistake: "delimitter" -> "delimiter" Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 14/29] netfilter: nft_hash: fix non static symbol warning Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 15/29] netfilter: nf_tables: typo in trace attribute definition Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 16/29] netfilter: nf_tables: introduce nft_chain_parse_hook() Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 17/29] netfilter: nf_tables: reject hook configuration updates on existing chains Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 18/29] rhashtable: add rhashtable_lookup_get_insert_key() Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 19/29] netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 20/29] netfilter: nf_tables: Use nla_put_be32() to dump immediate parameters Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 21/29] netfilter: restart search if moved to other chain Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 22/29] netfilter: don't rely on DYING bit to detect when destroy event was sent Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 23/29] netfilter: conntrack: get rid of conntrack timer Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 24/29] netfilter: evict stale entries on netlink dumps Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 25/29] netfilter: conntrack: add gc worker to remove timed-out entries Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 26/29] netfilter: conntrack: resched gc again if eviction rate is high Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 27/29] netfilter: remove __nf_ct_kill_acct helper Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 28/29] netfilter: log_arp: Use ARPHRD_ETHER instead of literal '1' Pablo Neira Ayuso
2016-09-05 10:58 ` [PATCH 29/29] netfilter: log: Check param to avoid overflow in nf_log_set Pablo Neira Ayuso
2016-09-06 19:47 ` [PATCH 00/29] Netfilter updates for net-next David Miller

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