From patchwork Wed Mar 25 11:27:07 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 25077 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 46E93DDD0C for ; Wed, 25 Mar 2009 22:27:25 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753961AbZCYL1U (ORCPT ); Wed, 25 Mar 2009 07:27:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753803AbZCYL1U (ORCPT ); Wed, 25 Mar 2009 07:27:20 -0400 Received: from gw1.cosmosbay.com ([212.99.114.194]:55456 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753086AbZCYL1S convert rfc822-to-8bit (ORCPT ); Wed, 25 Mar 2009 07:27:18 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) by gw1.cosmosbay.com (8.13.7/8.13.7) with ESMTP id n2PBR7Wu008907; Wed, 25 Mar 2009 12:27:07 +0100 Message-ID: <49CA150B.2080203@cosmosbay.com> Date: Wed, 25 Mar 2009 12:27:07 +0100 From: Eric Dumazet User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: David Miller CC: Jan Engelhardt , kaber@trash.net, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: [PATCH] netfilter: factorize ifname_compare() References: <20090324.132954.148903398.davem@davemloft.net> <49C94B6A.5020304@cosmosbay.com> <20090324.141848.119353425.davem@davemloft.net> <49C952FE.7070202@cosmosbay.com> In-Reply-To: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [0.0.0.0]); Wed, 25 Mar 2009 12:27:07 +0100 (CET) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jan Engelhardt a écrit : > On Tuesday 2009-03-24 22:39, Eric Dumazet wrote: >> memcmp() is fine, but how is it solving the masking problem we have ? > > You are right; we would have to calculate the prefix length of the > mask first. (And I think we can assume that there will not be any 1s > in the mask after the first 0.) It would consume CPU indeed. > >> Also in the case of arp_tables, _a is long word aligned, while _b and _mask >> are not. >> >> If you look various ifname_compare(), we have two different implementations. >> >> So yes, a factorization is possible for three ip_tables.c, ip6_tables.c and >> xt_physdev.c. > > Very well. Here is a patch to factorize these functions, as suggested by Jan Thank you [PATCH] netfilter: factorize ifname_compare() We use same not trivial helper function in four places. We can factorize it. Signed-off-by: Eric Dumazet --- include/linux/netfilter/x_tables.h | 23 +++++++++++++++++++++++ net/ipv4/netfilter/arp_tables.c | 14 +------------- net/ipv4/netfilter/ip_tables.c | 23 ++--------------------- net/ipv6/netfilter/ip6_tables.c | 23 ++--------------------- net/netfilter/xt_physdev.c | 21 ++------------------- 5 files changed, 30 insertions(+), 74 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 diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index e8e08d0..72918b7 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -435,6 +435,29 @@ extern void xt_free_table_info(struct xt_table_info *info); extern void xt_table_entry_swap_rcu(struct xt_table_info *old, struct xt_table_info *new); +/* + * This helper is performance critical and must be inlined + */ +static inline unsigned long ifname_compare_aligned(const char *_a, + const char *_b, + const char *_mask) +{ + const unsigned long *a = (const unsigned long *)_a; + const unsigned long *b = (const unsigned long *)_b; + const unsigned long *mask = (const unsigned long *)_mask; + unsigned long ret; + + ret = (a[0] ^ b[0]) & mask[0]; + if (IFNAMSIZ > sizeof(unsigned long)) + ret |= (a[1] ^ b[1]) & mask[1]; + if (IFNAMSIZ > 2 * sizeof(unsigned long)) + ret |= (a[2] ^ b[2]) & mask[2]; + if (IFNAMSIZ > 3 * sizeof(unsigned long)) + ret |= (a[3] ^ b[3]) & mask[3]; + BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); + return ret; +} + #ifdef CONFIG_COMPAT #include diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 84b9c17..ee1133c 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -81,19 +81,7 @@ static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) { #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS - const unsigned long *a = (const unsigned long *)_a; - const unsigned long *b = (const unsigned long *)_b; - const unsigned long *mask = (const unsigned long *)_mask; - unsigned long ret; - - ret = (a[0] ^ b[0]) & mask[0]; - if (IFNAMSIZ > sizeof(unsigned long)) - ret |= (a[1] ^ b[1]) & mask[1]; - if (IFNAMSIZ > 2 * sizeof(unsigned long)) - ret |= (a[2] ^ b[2]) & mask[2]; - if (IFNAMSIZ > 3 * sizeof(unsigned long)) - ret |= (a[3] ^ b[3]) & mask[3]; - BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); + unsigned long ret = ifname_compare_aligned(_a, _b, _mask); #else unsigned long ret = 0; const u16 *a = (const u16 *)_a; diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index e5294ae..41c59e3 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -74,25 +74,6 @@ do { \ Hence the start of any table is given by get_table() below. */ -static unsigned long ifname_compare(const char *_a, const char *_b, - const unsigned char *_mask) -{ - const unsigned long *a = (const unsigned long *)_a; - const unsigned long *b = (const unsigned long *)_b; - const unsigned long *mask = (const unsigned long *)_mask; - unsigned long ret; - - ret = (a[0] ^ b[0]) & mask[0]; - if (IFNAMSIZ > sizeof(unsigned long)) - ret |= (a[1] ^ b[1]) & mask[1]; - if (IFNAMSIZ > 2 * sizeof(unsigned long)) - ret |= (a[2] ^ b[2]) & mask[2]; - if (IFNAMSIZ > 3 * sizeof(unsigned long)) - ret |= (a[3] ^ b[3]) & mask[3]; - BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); - return ret; -} - /* Returns whether matches rule or not. */ /* Performance critical - called for every packet */ static inline bool @@ -121,7 +102,7 @@ ip_packet_match(const struct iphdr *ip, return false; } - ret = ifname_compare(indev, ipinfo->iniface, ipinfo->iniface_mask); + ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask); if (FWINV(ret != 0, IPT_INV_VIA_IN)) { dprintf("VIA in mismatch (%s vs %s).%s\n", @@ -130,7 +111,7 @@ ip_packet_match(const struct iphdr *ip, return false; } - ret = ifname_compare(outdev, ipinfo->outiface, ipinfo->outiface_mask); + ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask); if (FWINV(ret != 0, IPT_INV_VIA_OUT)) { dprintf("VIA out mismatch (%s vs %s).%s\n", diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 34af7bb..e59662b 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -89,25 +89,6 @@ ip6t_ext_hdr(u8 nexthdr) (nexthdr == IPPROTO_DSTOPTS) ); } -static unsigned long ifname_compare(const char *_a, const char *_b, - const unsigned char *_mask) -{ - const unsigned long *a = (const unsigned long *)_a; - const unsigned long *b = (const unsigned long *)_b; - const unsigned long *mask = (const unsigned long *)_mask; - unsigned long ret; - - ret = (a[0] ^ b[0]) & mask[0]; - if (IFNAMSIZ > sizeof(unsigned long)) - ret |= (a[1] ^ b[1]) & mask[1]; - if (IFNAMSIZ > 2 * sizeof(unsigned long)) - ret |= (a[2] ^ b[2]) & mask[2]; - if (IFNAMSIZ > 3 * sizeof(unsigned long)) - ret |= (a[3] ^ b[3]) & mask[3]; - BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); - return ret; -} - /* Returns whether matches rule or not. */ /* Performance critical - called for every packet */ static inline bool @@ -138,7 +119,7 @@ ip6_packet_match(const struct sk_buff *skb, return false; } - ret = ifname_compare(indev, ip6info->iniface, ip6info->iniface_mask); + ret = ifname_compare_aligned(indev, ip6info->iniface, ip6info->iniface_mask); if (FWINV(ret != 0, IP6T_INV_VIA_IN)) { dprintf("VIA in mismatch (%s vs %s).%s\n", @@ -147,7 +128,7 @@ ip6_packet_match(const struct sk_buff *skb, return false; } - ret = ifname_compare(outdev, ip6info->outiface, ip6info->outiface_mask); + ret = ifname_compare_aligned(outdev, ip6info->outiface, ip6info->outiface_mask); if (FWINV(ret != 0, IP6T_INV_VIA_OUT)) { dprintf("VIA out mismatch (%s vs %s).%s\n", diff --git a/net/netfilter/xt_physdev.c b/net/netfilter/xt_physdev.c index 44a234e..8d28ca5 100644 --- a/net/netfilter/xt_physdev.c +++ b/net/netfilter/xt_physdev.c @@ -20,23 +20,6 @@ MODULE_DESCRIPTION("Xtables: Bridge physical device match"); MODULE_ALIAS("ipt_physdev"); MODULE_ALIAS("ip6t_physdev"); -static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) -{ - const unsigned long *a = (const unsigned long *)_a; - const unsigned long *b = (const unsigned long *)_b; - const unsigned long *mask = (const unsigned long *)_mask; - unsigned long ret; - - ret = (a[0] ^ b[0]) & mask[0]; - if (IFNAMSIZ > sizeof(unsigned long)) - ret |= (a[1] ^ b[1]) & mask[1]; - if (IFNAMSIZ > 2 * sizeof(unsigned long)) - ret |= (a[2] ^ b[2]) & mask[2]; - if (IFNAMSIZ > 3 * sizeof(unsigned long)) - ret |= (a[3] ^ b[3]) & mask[3]; - BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long)); - return ret; -} static bool physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par) @@ -85,7 +68,7 @@ physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par) if (!(info->bitmask & XT_PHYSDEV_OP_IN)) goto match_outdev; indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname; - ret = ifname_compare(indev, info->physindev, info->in_mask); + ret = ifname_compare_aligned(indev, info->physindev, info->in_mask); if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN)) return false; @@ -95,7 +78,7 @@ match_outdev: return true; outdev = nf_bridge->physoutdev ? nf_bridge->physoutdev->name : nulldevname; - ret = ifname_compare(outdev, info->physoutdev, info->out_mask); + ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask); return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT)); }