Eric Lee / smarc-fsl-linux-kernel

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net/netfilter/xt_CHECKSUM.c 2.18 KB
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d2912cb15   Thomas Gleixner   treewide: Replace... 
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  // SPDX-License-Identifier: GPL-2.0-only
edf0e1fb0   Michael S. Tsirkin   netfilter: add CH... 
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  /* iptables module for the packet checksum mangling
   *
   * (C) 2002 by Harald Welte <laforge@netfilter.org>
   * (C) 2010 Red Hat, Inc.
   *
   * Author: Michael S. Tsirkin <mst@redhat.com>
edf0e1fb0   Michael S. Tsirkin   netfilter: add CH... 
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  */
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  #include <linux/module.h>
  #include <linux/skbuff.h>
  
  #include <linux/netfilter/x_tables.h>
  #include <linux/netfilter/xt_CHECKSUM.h>
10568f6c5   Florian Westphal   netfilter: xt_che... 
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  #include <linux/netfilter_ipv4/ip_tables.h>
  #include <linux/netfilter_ipv6/ip6_tables.h>
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  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Michael S. Tsirkin <mst@redhat.com>");
  MODULE_DESCRIPTION("Xtables: checksum modification");
  MODULE_ALIAS("ipt_CHECKSUM");
  MODULE_ALIAS("ip6t_CHECKSUM");
  
  static unsigned int
  checksum_tg(struct sk_buff *skb, const struct xt_action_param *par)
  {
10568f6c5   Florian Westphal   netfilter: xt_che... 
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  	if (skb->ip_summed == CHECKSUM_PARTIAL && !skb_is_gso(skb))
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  		skb_checksum_help(skb);
  
  	return XT_CONTINUE;
  }
  
  static int checksum_tg_check(const struct xt_tgchk_param *par)
  {
  	const struct xt_CHECKSUM_info *einfo = par->targinfo;
10568f6c5   Florian Westphal   netfilter: xt_che... 
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  	const struct ip6t_ip6 *i6 = par->entryinfo;
  	const struct ipt_ip *i4 = par->entryinfo;
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  	if (einfo->operation & ~XT_CHECKSUM_OP_FILL) {
b26066447   Florian Westphal   netfilter: x_tabl... 
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  		pr_info_ratelimited("unsupported CHECKSUM operation %x
  ",
  				    einfo->operation);
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  		return -EINVAL;
  	}
0cc9501f9   Florian Westphal   netfilter: x_tabl... 
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  	if (!einfo->operation)
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  		return -EINVAL;
0cc9501f9   Florian Westphal   netfilter: x_tabl... 
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10568f6c5
 
 Florian Westphal
 
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  	switch (par->family) {
  	case NFPROTO_IPV4:
  		if (i4->proto == IPPROTO_UDP &&
  		    (i4->invflags & XT_INV_PROTO) == 0)
  			return 0;
  		break;
  	case NFPROTO_IPV6:
  		if ((i6->flags & IP6T_F_PROTO) &&
  		    i6->proto == IPPROTO_UDP &&
  		    (i6->invflags & XT_INV_PROTO) == 0)
  			return 0;
  		break;
  	}
  
  	pr_warn_once("CHECKSUM should be avoided.  If really needed, restrict with \"-p udp\" and only use in OUTPUT
  ");









edf0e1fb0
 
 Michael S. Tsirkin
 
netfilter: add CH...




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  	return 0;
  }
  
  static struct xt_target checksum_tg_reg __read_mostly = {
  	.name		= "CHECKSUM",
  	.family		= NFPROTO_UNSPEC,
  	.target		= checksum_tg,
  	.targetsize	= sizeof(struct xt_CHECKSUM_info),
  	.table		= "mangle",
  	.checkentry	= checksum_tg_check,
  	.me		= THIS_MODULE,
  };
  
  static int __init checksum_tg_init(void)
  {
  	return xt_register_target(&checksum_tg_reg);
  }
  
  static void __exit checksum_tg_exit(void)
  {
  	xt_unregister_target(&checksum_tg_reg);
  }
  
  module_init(checksum_tg_init);
  module_exit(checksum_tg_exit);