ip.h 13.8 KB
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/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the IP module.
 *
 * Version:	@(#)ip.h	1.0.2	05/07/93
 *
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 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *
 * Changes:
 *		Mike McLagan    :       Routing by source
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#ifndef _IP_H
#define _IP_H

#include <linux/types.h>
#include <linux/ip.h>
#include <linux/in.h>
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#include <linux/skbuff.h>
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#include <net/inet_sock.h>
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#include <net/snmp.h>
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#include <net/flow.h>
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struct sock;

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struct inet_skb_parm {
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	struct ip_options	opt;		/* Compiled IP options		*/
	unsigned char		flags;

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#define IPSKB_FORWARDED		1
#define IPSKB_XFRM_TUNNEL_SIZE	2
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#define IPSKB_XFRM_TRANSFORMED	4
#define IPSKB_FRAG_COMPLETE	8
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#define IPSKB_REROUTED		16
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	u16			frag_max_size;
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};

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static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
{
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	return ip_hdr(skb)->ihl * 4;
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}

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struct ipcm_cookie {
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	__be32			addr;
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	int			oif;
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	struct ip_options_rcu	*opt;
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	__u8			tx_flags;
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};

#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))

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struct ip_ra_chain {
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	struct ip_ra_chain __rcu *next;
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	struct sock		*sk;
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	union {
		void			(*destructor)(struct sock *);
		struct sock		*saved_sk;
	};
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	struct rcu_head		rcu;
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};

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extern struct ip_ra_chain __rcu *ip_ra_chain;
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/* IP flags. */
#define IP_CE		0x8000		/* Flag: "Congestion"		*/
#define IP_DF		0x4000		/* Flag: "Don't Fragment"	*/
#define IP_MF		0x2000		/* Flag: "More Fragments"	*/
#define IP_OFFSET	0x1FFF		/* "Fragment Offset" part	*/

#define IP_FRAG_TIME	(30 * HZ)		/* fragment lifetime	*/

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struct msghdr;
struct net_device;
struct packet_type;
struct rtable;
struct sockaddr;

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extern int		igmp_mc_proc_init(void);

/*
 *	Functions provided by ip.c
 */

extern int		ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
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					      __be32 saddr, __be32 daddr,
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					      struct ip_options_rcu *opt);
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extern int		ip_rcv(struct sk_buff *skb, struct net_device *dev,
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			       struct packet_type *pt, struct net_device *orig_dev);
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extern int		ip_local_deliver(struct sk_buff *skb);
extern int		ip_mr_input(struct sk_buff *skb);
extern int		ip_output(struct sk_buff *skb);
extern int		ip_mc_output(struct sk_buff *skb);
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extern int		ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
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extern int		ip_do_nat(struct sk_buff *skb);
extern void		ip_send_check(struct iphdr *ip);
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extern int		__ip_local_out(struct sk_buff *skb);
extern int		ip_local_out(struct sk_buff *skb);
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extern int		ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
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extern void		ip_init(void);
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extern int		ip_append_data(struct sock *sk, struct flowi4 *fl4,
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				       int getfrag(void *from, char *to, int offset, int len,
						   int odd, struct sk_buff *skb),
				void *from, int len, int protolen,
				struct ipcm_cookie *ipc,
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				struct rtable **rt,
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				unsigned int flags);
extern int		ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
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extern ssize_t		ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
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				int offset, size_t size, int flags);
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extern struct sk_buff  *__ip_make_skb(struct sock *sk,
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				      struct flowi4 *fl4,
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				      struct sk_buff_head *queue,
				      struct inet_cork *cork);
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extern int		ip_send_skb(struct net *net, struct sk_buff *skb);
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extern int		ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
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extern void		ip_flush_pending_frames(struct sock *sk);
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extern struct sk_buff  *ip_make_skb(struct sock *sk,
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				    struct flowi4 *fl4,
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				    int getfrag(void *from, char *to, int offset, int len,
						int odd, struct sk_buff *skb),
				    void *from, int length, int transhdrlen,
				    struct ipcm_cookie *ipc,
				    struct rtable **rtp,
				    unsigned int flags);

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static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
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{
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	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
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}
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/* datagram.c */
extern int		ip4_datagram_connect(struct sock *sk, 
					     struct sockaddr *uaddr, int addr_len);

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extern void ip4_datagram_release_cb(struct sock *sk);

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struct ip_reply_arg {
	struct kvec iov[1];   
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	int	    flags;
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	__wsum 	    csum;
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	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */
				/* -1 if not needed */ 
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	int	    bound_dev_if;
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	u8  	    tos;
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}; 

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#define IP_REPLY_ARG_NOSRCCHECK 1

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static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
{
	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
}

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void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
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			   __be32 saddr, const struct ip_reply_arg *arg,
			   unsigned int len);
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struct ipv4_config {
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	int	log_martians;
	int	no_pmtu_disc;
};

extern struct ipv4_config ipv4_config;
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#define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define IP_INC_STATS_BH(net, field)	SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
#define IP_ADD_STATS(net, field, val)	SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
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#define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)
#define NET_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
#define NET_INC_STATS_USER(net, field) 	SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
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extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
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#if BITS_PER_LONG==32
extern u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
#else
static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
{
	return snmp_fold_field(mib, offt);
}
#endif
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extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
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static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
{
	int i;

	BUG_ON(ptr == NULL);
	for (i = 0; i < SNMP_ARRAY_SZ; i++) {
		free_percpu(ptr[i]);
		ptr[i] = NULL;
	}
}
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extern struct local_ports {
	seqlock_t	lock;
	int		range[2];
} sysctl_local_ports;
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extern void inet_get_local_port_range(int *low, int *high);

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extern unsigned long *sysctl_local_reserved_ports;
static inline int inet_is_reserved_local_port(int port)
{
	return test_bit(port, sysctl_local_reserved_ports);
}

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extern int sysctl_ip_nonlocal_bind;
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/* From inetpeer.c */
extern int inet_peer_threshold;
extern int inet_peer_minttl;
extern int inet_peer_maxttl;

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/* From ip_input.c */
extern int sysctl_ip_early_demux;

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/* From ip_output.c */
extern int sysctl_ip_dynaddr;

extern void ipfrag_init(void);

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extern void ip_static_sysctl_init(void);

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static inline bool ip_is_fragment(const struct iphdr *iph)
{
	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
}

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#ifdef CONFIG_INET
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#include <net/dst.h>

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/* The function in 2.2 was invalid, producing wrong result for
 * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
static inline
int ip_decrease_ttl(struct iphdr *iph)
{
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	u32 check = (__force u32)iph->check;
	check += (__force u32)htons(0x0100);
	iph->check = (__force __sum16)(check + (check>=0xFFFF));
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	return --iph->ttl;
}

static inline
int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
{
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	return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
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		(inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
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		 !(dst_metric_locked(dst, RTAX_MTU)));
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}

extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);

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static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
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{
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	struct iphdr *iph = ip_hdr(skb);

	if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
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		/* This is only to work around buggy Windows95/2000
		 * VJ compression implementations.  If the ID field
		 * does not change, they drop every other packet in
		 * a TCP stream using header compression.
		 */
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		iph->id = (sk && inet_sk(sk)->inet_daddr) ?
					htons(inet_sk(sk)->inet_id++) : 0;
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	} else
		__ip_select_ident(iph, dst, 0);
}

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static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
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{
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	struct iphdr *iph = ip_hdr(skb);

	if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
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		if (sk && inet_sk(sk)->inet_daddr) {
			iph->id = htons(inet_sk(sk)->inet_id);
			inet_sk(sk)->inet_id += 1 + more;
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		} else
			iph->id = 0;
	} else
		__ip_select_ident(iph, dst, more);
}

/*
 *	Map a multicast IP onto multicast MAC for type ethernet.
 */

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static inline void ip_eth_mc_map(__be32 naddr, char *buf)
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{
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	__u32 addr=ntohl(naddr);
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	buf[0]=0x01;
	buf[1]=0x00;
	buf[2]=0x5e;
	buf[5]=addr&0xFF;
	addr>>=8;
	buf[4]=addr&0xFF;
	addr>>=8;
	buf[3]=addr&0x7F;
}

/*
 *	Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 *	Leave P_Key as 0 to be filled in by driver.
 */

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static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
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{
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	__u32 addr;
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	unsigned char scope = broadcast[5] & 0xF;

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	buf[0]  = 0;		/* Reserved */
	buf[1]  = 0xff;		/* Multicast QPN */
	buf[2]  = 0xff;
	buf[3]  = 0xff;
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	addr    = ntohl(naddr);
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	buf[4]  = 0xff;
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	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
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	buf[6]  = 0x40;		/* IPv4 signature */
	buf[7]  = 0x1b;
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	buf[8]  = broadcast[8];		/* P_Key */
	buf[9]  = broadcast[9];
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	buf[10] = 0;
	buf[11] = 0;
	buf[12] = 0;
	buf[13] = 0;
	buf[14] = 0;
	buf[15] = 0;
	buf[19] = addr & 0xff;
	addr  >>= 8;
	buf[18] = addr & 0xff;
	addr  >>= 8;
	buf[17] = addr & 0xff;
	addr  >>= 8;
	buf[16] = addr & 0x0f;
}

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static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
{
	if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
		memcpy(buf, broadcast, 4);
	else
		memcpy(buf, &naddr, sizeof(naddr));
}

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#if IS_ENABLED(CONFIG_IPV6)
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#include <linux/ipv6.h>
#endif

static __inline__ void inet_reset_saddr(struct sock *sk)
{
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	inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
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#if IS_ENABLED(CONFIG_IPV6)
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	if (sk->sk_family == PF_INET6) {
		struct ipv6_pinfo *np = inet6_sk(sk);

		memset(&np->saddr, 0, sizeof(np->saddr));
		memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
	}
#endif
}

#endif

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static inline int sk_mc_loop(struct sock *sk)
{
	if (!sk)
		return 1;
	switch (sk->sk_family) {
	case AF_INET:
		return inet_sk(sk)->mc_loop;
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#if IS_ENABLED(CONFIG_IPV6)
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	case AF_INET6:
		return inet6_sk(sk)->mc_loop;
#endif
	}
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	WARN_ON(1);
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	return 1;
}

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extern bool ip_call_ra_chain(struct sk_buff *skb);
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/*
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 *	Functions provided by ip_fragment.c
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 */

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enum ip_defrag_users {
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	IP_DEFRAG_LOCAL_DELIVER,
	IP_DEFRAG_CALL_RA_CHAIN,
	IP_DEFRAG_CONNTRACK_IN,
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	__IP_DEFRAG_CONNTRACK_IN_END	= IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
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	IP_DEFRAG_CONNTRACK_OUT,
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	__IP_DEFRAG_CONNTRACK_OUT_END	= IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
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	IP_DEFRAG_CONNTRACK_BRIDGE_IN,
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	__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
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	IP_DEFRAG_VS_IN,
	IP_DEFRAG_VS_OUT,
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	IP_DEFRAG_VS_FWD,
	IP_DEFRAG_AF_PACKET,
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	IP_DEFRAG_MACVLAN,
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};

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int ip_defrag(struct sk_buff *skb, u32 user);
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#ifdef CONFIG_INET
struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
#else
static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
{
	return skb;
}
#endif
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int ip_frag_mem(struct net *net);
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int ip_frag_nqueues(struct net *net);
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/*
 *	Functions provided by ip_forward.c
 */
 
extern int ip_forward(struct sk_buff *skb);
 
/*
 *	Functions provided by ip_options.c
 */
 
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extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
			     __be32 daddr, struct rtable *rt, int is_frag);
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extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
extern void ip_options_fragment(struct sk_buff *skb);
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extern int ip_options_compile(struct net *net,
			      struct ip_options *opt, struct sk_buff *skb);
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extern int ip_options_get(struct net *net, struct ip_options_rcu **optp,
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			  unsigned char *data, int optlen);
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extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
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				    unsigned char __user *data, int optlen);
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extern void ip_options_undo(struct ip_options * opt);
extern void ip_forward_options(struct sk_buff *skb);
extern int ip_options_rcv_srr(struct sk_buff *skb);

/*
 *	Functions provided by ip_sockglue.c
 */

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extern void	ipv4_pktinfo_prepare(struct sk_buff *skb);
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extern void	ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
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extern int	ip_cmsg_send(struct net *net,
			     struct msghdr *msg, struct ipcm_cookie *ipc);
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extern int	ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen);
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extern int	ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
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extern int	compat_ip_setsockopt(struct sock *sk, int level,
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			int optname, char __user *optval, unsigned int optlen);
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extern int	compat_ip_getsockopt(struct sock *sk, int level,
			int optname, char __user *optval, int __user *optlen);
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extern int	ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));

extern int 	ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
extern void	ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, 
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			      __be16 port, u32 info, u8 *payload);
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extern void	ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
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			       u32 info);

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#ifdef CONFIG_PROC_FS
extern int ip_misc_proc_init(void);
#endif

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#endif	/* _IP_H */