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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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6869c4d8e0
As discussed at netconf'05, we're trying to save every bit in sk_buff. The patch below makes sk_buff 8 bytes smaller. I did some basic testing on my notebook and it seems to work. The only real in-tree user of nfcache was IPVS, who only needs a single bit. Unfortunately I couldn't find some other free bit in sk_buff to stuff that bit into, so I introduced a separate field for them. Maybe the IPVS guys can resolve that to further save space. Initially I wanted to shrink pkt_type to three bits (PACKET_HOST and alike are only 6 values defined), but unfortunately the bluetooth code overloads pkt_type :( The conntrack-event-api (out-of-tree) uses nfcache, but Rusty just came up with a way how to do it without any skb fields, so it's safe to remove it. - remove all never-implemented 'nfcache' code - don't have ipvs code abuse 'nfcache' field. currently get's their own compile-conditional skb->ipvs_property field. IPVS maintainers can decide to move this bit elswhere, but nfcache needs to die. - remove skb->nfcache field to save 4 bytes - move skb->nfctinfo into three unused bits to save further 4 bytes Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
121 lines
3.4 KiB
C
121 lines
3.4 KiB
C
/* This kernel module is used to modify the connection mark values, or
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* to optionally restore the skb nfmark from the connection mark
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*
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* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
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* by Henrik Nordstrom <hno@marasystems.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <net/checksum.h>
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MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>");
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MODULE_DESCRIPTION("IP tables CONNMARK matching module");
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MODULE_LICENSE("GPL");
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_CONNMARK.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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static unsigned int
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target(struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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unsigned int hooknum,
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const void *targinfo,
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void *userinfo)
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{
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const struct ipt_connmark_target_info *markinfo = targinfo;
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u_int32_t diff;
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u_int32_t nfmark;
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u_int32_t newmark;
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enum ip_conntrack_info ctinfo;
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struct ip_conntrack *ct = ip_conntrack_get((*pskb), &ctinfo);
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if (ct) {
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switch(markinfo->mode) {
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case IPT_CONNMARK_SET:
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newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
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if (newmark != ct->mark)
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ct->mark = newmark;
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break;
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case IPT_CONNMARK_SAVE:
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newmark = (ct->mark & ~markinfo->mask) | ((*pskb)->nfmark & markinfo->mask);
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if (ct->mark != newmark)
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ct->mark = newmark;
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break;
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case IPT_CONNMARK_RESTORE:
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nfmark = (*pskb)->nfmark;
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diff = (ct->mark ^ nfmark) & markinfo->mask;
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if (diff != 0)
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(*pskb)->nfmark = nfmark ^ diff;
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break;
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}
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}
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return IPT_CONTINUE;
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}
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static int
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checkentry(const char *tablename,
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const struct ipt_entry *e,
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void *targinfo,
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unsigned int targinfosize,
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unsigned int hook_mask)
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{
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struct ipt_connmark_target_info *matchinfo = targinfo;
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if (targinfosize != IPT_ALIGN(sizeof(struct ipt_connmark_target_info))) {
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printk(KERN_WARNING "CONNMARK: targinfosize %u != %Zu\n",
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targinfosize,
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IPT_ALIGN(sizeof(struct ipt_connmark_target_info)));
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return 0;
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}
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if (matchinfo->mode == IPT_CONNMARK_RESTORE) {
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if (strcmp(tablename, "mangle") != 0) {
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printk(KERN_WARNING "CONNMARK: restore can only be called from \"mangle\" table, not \"%s\"\n", tablename);
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return 0;
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}
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}
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if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
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printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
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return 0;
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}
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return 1;
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}
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static struct ipt_target ipt_connmark_reg = {
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.name = "CONNMARK",
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.target = &target,
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.checkentry = &checkentry,
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.me = THIS_MODULE
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};
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static int __init init(void)
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{
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return ipt_register_target(&ipt_connmark_reg);
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}
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static void __exit fini(void)
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{
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ipt_unregister_target(&ipt_connmark_reg);
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}
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module_init(init);
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module_exit(fini);
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