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	 22441cfa0c
			
		
	
	
		22441cfa0c
		
	
	
	
	
		
			
			Problem observed:
               In IPv6, in the presence of multiple routers candidates to
               default gateway in one segment, each sending a different
               value of preference, the Linux hosts connected to the
               segment weren't selecting the right one in all the
               combinations possible of LOW/MEDIUM/HIGH preference.
This patch changes two files:
include/linux/icmpv6.h
               Get the "router_pref" bitfield in the right place
               (as RFC4191 says), named the bit left with this fix as
               "home_agent" (RFC3775 say that's his function)
net/ipv6/ndisc.c
               Corrects the binary logic behind the updating of the
               router preference in the flags of the routing table
Result:
               With this two fixes applied, the default route used by
               the system was to consistent with the rules mentioned
               in RFC4191 in case of changes in the value of preference
               in router advertisements
Signed-off-by: Pedro Ribeiro <pribeiro@net.ipl.pt>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
		
	
			
		
			
				
	
	
		
			199 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			199 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| #ifndef _LINUX_ICMPV6_H
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| #define _LINUX_ICMPV6_H
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| 
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| #include <asm/byteorder.h>
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| 
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| struct icmp6hdr {
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| 
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| 	__u8		icmp6_type;
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| 	__u8		icmp6_code;
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| 	__sum16		icmp6_cksum;
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| 
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| 
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| 	union {
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| 		__be32			un_data32[1];
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| 		__be16			un_data16[2];
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| 		__u8			un_data8[4];
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| 
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| 		struct icmpv6_echo {
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| 			__be16		identifier;
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| 			__be16		sequence;
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| 		} u_echo;
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| 
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|                 struct icmpv6_nd_advt {
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| #if defined(__LITTLE_ENDIAN_BITFIELD)
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|                         __u32		reserved:5,
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|                         		override:1,
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|                         		solicited:1,
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|                         		router:1,
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| 					reserved2:24;
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| #elif defined(__BIG_ENDIAN_BITFIELD)
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|                         __u32		router:1,
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| 					solicited:1,
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|                         		override:1,
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|                         		reserved:29;
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| #else
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| #error	"Please fix <asm/byteorder.h>"
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| #endif						
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|                 } u_nd_advt;
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| 
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|                 struct icmpv6_nd_ra {
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| 			__u8		hop_limit;
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| #if defined(__LITTLE_ENDIAN_BITFIELD)
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| 			__u8		reserved:3,
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| 					router_pref:2,
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| 					home_agent:1,
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| 					other:1,
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| 					managed:1;
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| 
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| #elif defined(__BIG_ENDIAN_BITFIELD)
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| 			__u8		managed:1,
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| 					other:1,
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| 					home_agent:1,
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| 					router_pref:2,
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| 					reserved:3;
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| #else
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| #error	"Please fix <asm/byteorder.h>"
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| #endif
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| 			__be16		rt_lifetime;
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|                 } u_nd_ra;
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| 
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| 	} icmp6_dataun;
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| 
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| #define icmp6_identifier	icmp6_dataun.u_echo.identifier
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| #define icmp6_sequence		icmp6_dataun.u_echo.sequence
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| #define icmp6_pointer		icmp6_dataun.un_data32[0]
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| #define icmp6_mtu		icmp6_dataun.un_data32[0]
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| #define icmp6_unused		icmp6_dataun.un_data32[0]
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| #define icmp6_maxdelay		icmp6_dataun.un_data16[0]
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| #define icmp6_router		icmp6_dataun.u_nd_advt.router
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| #define icmp6_solicited		icmp6_dataun.u_nd_advt.solicited
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| #define icmp6_override		icmp6_dataun.u_nd_advt.override
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| #define icmp6_ndiscreserved	icmp6_dataun.u_nd_advt.reserved
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| #define icmp6_hop_limit		icmp6_dataun.u_nd_ra.hop_limit
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| #define icmp6_addrconf_managed	icmp6_dataun.u_nd_ra.managed
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| #define icmp6_addrconf_other	icmp6_dataun.u_nd_ra.other
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| #define icmp6_rt_lifetime	icmp6_dataun.u_nd_ra.rt_lifetime
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| #define icmp6_router_pref	icmp6_dataun.u_nd_ra.router_pref
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| };
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| 
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| #ifdef __KERNEL__
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| #include <linux/skbuff.h>
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| 
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| static inline struct icmp6hdr *icmp6_hdr(const struct sk_buff *skb)
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| {
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| 	return (struct icmp6hdr *)skb_transport_header(skb);
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| }
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| #endif
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| 
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| #define ICMPV6_ROUTER_PREF_LOW		0x3
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| #define ICMPV6_ROUTER_PREF_MEDIUM	0x0
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| #define ICMPV6_ROUTER_PREF_HIGH		0x1
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| #define ICMPV6_ROUTER_PREF_INVALID	0x2
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| 
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| #define ICMPV6_DEST_UNREACH		1
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| #define ICMPV6_PKT_TOOBIG		2
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| #define ICMPV6_TIME_EXCEED		3
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| #define ICMPV6_PARAMPROB		4
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| 
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| #define ICMPV6_INFOMSG_MASK		0x80
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| 
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| #define ICMPV6_ECHO_REQUEST		128
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| #define ICMPV6_ECHO_REPLY		129
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| #define ICMPV6_MGM_QUERY		130
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| #define ICMPV6_MGM_REPORT       	131
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| #define ICMPV6_MGM_REDUCTION    	132
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| 
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| #define ICMPV6_NI_QUERY			139
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| #define ICMPV6_NI_REPLY			140
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| 
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| #define ICMPV6_MLD2_REPORT		143
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| 
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| #define ICMPV6_DHAAD_REQUEST		144
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| #define ICMPV6_DHAAD_REPLY		145
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| #define ICMPV6_MOBILE_PREFIX_SOL	146
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| #define ICMPV6_MOBILE_PREFIX_ADV	147
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| 
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| /*
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|  *	Codes for Destination Unreachable
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|  */
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| #define ICMPV6_NOROUTE			0
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| #define ICMPV6_ADM_PROHIBITED		1
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| #define ICMPV6_NOT_NEIGHBOUR		2
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| #define ICMPV6_ADDR_UNREACH		3
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| #define ICMPV6_PORT_UNREACH		4
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| 
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| /*
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|  *	Codes for Time Exceeded
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|  */
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| #define ICMPV6_EXC_HOPLIMIT		0
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| #define ICMPV6_EXC_FRAGTIME		1
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| 
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| /*
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|  *	Codes for Parameter Problem
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|  */
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| #define ICMPV6_HDR_FIELD		0
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| #define ICMPV6_UNK_NEXTHDR		1
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| #define ICMPV6_UNK_OPTION		2
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| 
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| /*
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|  *	constants for (set|get)sockopt
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|  */
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| 
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| #define ICMPV6_FILTER			1
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| 
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| /*
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|  *	ICMPV6 filter
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|  */
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| 
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| #define ICMPV6_FILTER_BLOCK		1
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| #define ICMPV6_FILTER_PASS		2
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| #define ICMPV6_FILTER_BLOCKOTHERS	3
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| #define ICMPV6_FILTER_PASSONLY		4
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| 
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| struct icmp6_filter {
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| 	__u32		data[8];
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| };
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| 
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| /*
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|  *	Definitions for MLDv2
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|  */
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| #define MLD2_MODE_IS_INCLUDE	1
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| #define MLD2_MODE_IS_EXCLUDE	2
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| #define MLD2_CHANGE_TO_INCLUDE	3
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| #define MLD2_CHANGE_TO_EXCLUDE	4
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| #define MLD2_ALLOW_NEW_SOURCES	5
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| #define MLD2_BLOCK_OLD_SOURCES	6
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| 
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| #define MLD2_ALL_MCR_INIT { { { 0xff,0x02,0,0,0,0,0,0,0,0,0,0,0,0,0,0x16 } } }
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| 
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| #ifdef __KERNEL__
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| 
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| #include <linux/netdevice.h>
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| #include <linux/skbuff.h>
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| 
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| 
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| extern void				icmpv6_send(struct sk_buff *skb,
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| 						    int type, int code,
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| 						    __u32 info, 
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| 						    struct net_device *dev);
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| 
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| extern int				icmpv6_init(void);
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| extern int				icmpv6_err_convert(int type, int code,
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| 							   int *err);
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| extern void				icmpv6_cleanup(void);
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| extern void				icmpv6_param_prob(struct sk_buff *skb,
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| 							  int code, int pos);
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| 
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| struct flowi;
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| struct in6_addr;
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| extern void				icmpv6_flow_init(struct sock *sk,
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| 							 struct flowi *fl,
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| 							 u8 type,
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| 							 const struct in6_addr *saddr,
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| 							 const struct in6_addr *daddr,
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| 							 int oif);
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| #endif
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| 
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| #endif
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