mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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1d5cd90976
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
/* IP tables module for matching the value of the IPv4 and TCP ECN bits
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*
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* ipt_ecn.c,v 1.3 2002/05/29 15:09:00 laforge Exp
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*
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* (C) 2002 by Harald Welte <laforge@gnumonks.org>
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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 version 2 as
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* published by the Free Software Foundation.
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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/tcp.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ipt_ecn.h>
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MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
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MODULE_DESCRIPTION("iptables ECN matching module");
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MODULE_LICENSE("GPL");
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static inline int match_ip(const struct sk_buff *skb,
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const struct ipt_ecn_info *einfo)
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{
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return ((skb->nh.iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
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}
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static inline int match_tcp(const struct sk_buff *skb,
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const struct ipt_ecn_info *einfo,
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int *hotdrop)
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{
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struct tcphdr _tcph, *th;
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/* In practice, TCP match does this, so can't fail. But let's
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* be good citizens.
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*/
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th = skb_header_pointer(skb, skb->nh.iph->ihl * 4,
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sizeof(_tcph), &_tcph);
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if (th == NULL) {
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*hotdrop = 0;
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return 0;
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}
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if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
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if (einfo->invert & IPT_ECN_OP_MATCH_ECE) {
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if (th->ece == 1)
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return 0;
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} else {
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if (th->ece == 0)
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return 0;
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}
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}
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if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
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if (einfo->invert & IPT_ECN_OP_MATCH_CWR) {
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if (th->cwr == 1)
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return 0;
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} else {
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if (th->cwr == 0)
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return 0;
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}
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}
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return 1;
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}
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static int match(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const void *matchinfo,
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int offset, unsigned int protoff, int *hotdrop)
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{
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const struct ipt_ecn_info *info = matchinfo;
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if (info->operation & IPT_ECN_OP_MATCH_IP)
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if (!match_ip(skb, info))
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return 0;
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if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)) {
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if (skb->nh.iph->protocol != IPPROTO_TCP)
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return 0;
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if (!match_tcp(skb, info, hotdrop))
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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 int checkentry(const char *tablename, const void *ip_void,
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void *matchinfo, unsigned int matchsize,
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unsigned int hook_mask)
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{
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const struct ipt_ecn_info *info = matchinfo;
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const struct ipt_ip *ip = ip_void;
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if (info->operation & IPT_ECN_OP_MATCH_MASK)
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return 0;
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if (info->invert & IPT_ECN_OP_MATCH_MASK)
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return 0;
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if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)
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&& ip->proto != IPPROTO_TCP) {
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printk(KERN_WARNING "ipt_ecn: can't match TCP bits in rule for"
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" non-tcp packets\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_match ecn_match = {
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.name = "ecn",
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.match = match,
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.matchsize = sizeof(struct ipt_ecn_info),
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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_match(&ecn_match);
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}
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static void __exit fini(void)
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{
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ipt_unregister_match(&ecn_match);
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}
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module_init(init);
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module_exit(fini);
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