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/* SPDX-License-Identifier: GPL-2.0-or-later *//* * 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 * * Authors:	Ross Biro *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> *		Alan Cox, <gw4pts@gw4pts.ampr.org> * * Changes: *		Mike McLagan    :       Routing by source */#ifndef _IP_H#define _IP_H #include <linux/types.h>#include <linux/ip.h>#include <linux/in.h>#include <linux/skbuff.h>#include <linux/jhash.h>#include <linux/sockptr.h> #include <net/inet_sock.h>#include <net/route.h>#include <net/snmp.h>#include <net/flow.h>#include <net/flow_dissector.h>#include <net/netns/hash.h> #define IPV4_MAX_PMTU		65535U		/* RFC 2675, Section 5.1 */#define IPV4_MIN_MTU		68			/* RFC 791 */ extern unsigned int sysctl_fib_sync_mem;extern unsigned int sysctl_fib_sync_mem_min;extern unsigned int sysctl_fib_sync_mem_max; struct sock; struct inet_skb_parm {	int			iif;	struct ip_options	opt;		/* Compiled IP options		*/	u16			flags; #define IPSKB_FORWARDED		BIT(0)#define IPSKB_XFRM_TUNNEL_SIZE	BIT(1)#define IPSKB_XFRM_TRANSFORMED	BIT(2)#define IPSKB_FRAG_COMPLETE	BIT(3)#define IPSKB_REROUTED		BIT(4)#define IPSKB_DOREDIRECT	BIT(5)#define IPSKB_FRAG_PMTU		BIT(6)#define IPSKB_L3SLAVE		BIT(7) 	u16			frag_max_size;}; static inline bool ipv4_l3mdev_skb(u16 flags){	return !!(flags & IPSKB_L3SLAVE);} static inline unsigned int ip_hdrlen(const struct sk_buff *skb){	return ip_hdr(skb)->ihl * 4;} struct ipcm_cookie {	struct sockcm_cookie	sockc;	__be32			addr;	int			oif;	struct ip_options_rcu	*opt;	__u8			ttl;	__s16			tos;	char			priority;	__u16			gso_size;}; static inline void ipcm_init(struct ipcm_cookie *ipcm){	*ipcm = (struct ipcm_cookie) { .tos = -1 };} static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,				const struct inet_sock *inet){	ipcm_init(ipcm); 	ipcm->sockc.mark = inet->sk.sk_mark;	ipcm->sockc.tsflags = inet->sk.sk_tsflags;	ipcm->oif = inet->sk.sk_bound_dev_if;	ipcm->addr = inet->inet_saddr;} #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb)) /* return enslaved device index if relevant */static inline int inet_sdif(struct sk_buff *skb){#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)	if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))		return IPCB(skb)->iif;#endif	return 0;} /* Special input handler for packets caught by router alert option.   They are selected only by protocol field, and then processed likely   local ones; but only if someone wants them! Otherwise, router   not running rsvpd will kill RSVP.    It is user level problem, what it will make with them.   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),   but receiver should be enough clever f.e. to forward mtrace requests,   sent to multicast group to reach destination designated router. */ struct ip_ra_chain {	struct ip_ra_chain __rcu *next;	struct sock		*sk;	union {		void			(*destructor)(struct sock *);		struct sock		*saved_sk;	};	struct rcu_head		rcu;}; /* 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	*/ struct msghdr;struct net_device;struct packet_type;struct rtable;struct sockaddr; int igmp_mc_init(void); /* *	Functions provided by ip.c */ int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,			  __be32 saddr, __be32 daddr,			  struct ip_options_rcu *opt);int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,	   struct net_device *orig_dev);void ip_list_rcv(struct list_head *head, struct packet_type *pt,		 struct net_device *orig_dev);int ip_local_deliver(struct sk_buff *skb);void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);int ip_mr_input(struct sk_buff *skb);int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,		   int (*output)(struct net *, struct sock *, struct sk_buff *)); struct ip_fraglist_iter {	struct sk_buff	*frag;	struct iphdr	*iph;	int		offset;	unsigned int	hlen;}; void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,		      unsigned int hlen, struct ip_fraglist_iter *iter);void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter); static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter){	struct sk_buff *skb = iter->frag; 	iter->frag = skb->next;	skb_mark_not_on_list(skb); 	return skb;} struct ip_frag_state {	bool		DF;	unsigned int	hlen;	unsigned int	ll_rs;	unsigned int	mtu;	unsigned int	left;	int		offset;	int		ptr;	__be16		not_last_frag;}; void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,		  unsigned int mtu, bool DF, struct ip_frag_state *state);struct sk_buff *ip_frag_next(struct sk_buff *skb,			     struct ip_frag_state *state); void ip_send_check(struct iphdr *ip);int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb); int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,		    __u8 tos);void ip_init(void);int ip_append_data(struct sock *sk, struct flowi4 *fl4,		   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,		   struct rtable **rt,		   unsigned int flags);int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,		       struct sk_buff *skb);ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,		       int offset, size_t size, int flags);struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,			      struct sk_buff_head *queue,			      struct inet_cork *cork);int ip_send_skb(struct net *net, struct sk_buff *skb);int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);void ip_flush_pending_frames(struct sock *sk);struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,			    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,			    struct inet_cork *cork, unsigned int flags); int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl); static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4){	return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);} static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet){	return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);} static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk){	return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);} /* datagram.c */int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); void ip4_datagram_release_cb(struct sock *sk); struct ip_reply_arg {	struct kvec iov[1];	int	    flags;	__wsum 	    csum;	int	    csumoffset; /* u16 offset of csum in iov[0].iov_base */				/* -1 if not needed */	int	    bound_dev_if;	u8  	    tos;	kuid_t	    uid;}; #define IP_REPLY_ARG_NOSRCCHECK 1 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;} void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,			   const struct ip_options *sopt,			   __be32 daddr, __be32 saddr,			   const struct ip_reply_arg *arg,			   unsigned int len, u64 transmit_time); #define IP_INC_STATS(net, field)	SNMP_INC_STATS64((net)->mib.ip_statistics, field)#define __IP_INC_STATS(net, field)	__SNMP_INC_STATS64((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(net, field, val) __SNMP_ADD_STATS64((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(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)#define NET_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.net_statistics, field)#define __NET_INC_STATS(net, field)	__SNMP_INC_STATS((net)->mib.net_statistics, field)#define NET_ADD_STATS(net, field, adnd)	SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd) u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offct);unsigned long snmp_fold_field(void __percpu *mib, int offt);#if BITS_PER_LONG==32u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,			 size_t syncp_offset);u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);#elsestatic inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,					size_t syncp_offset){	return snmp_get_cpu_field(mib, cpu, offct); } static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off){	return snmp_fold_field(mib, offt);}#endif #define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \{ \	int i, c; \	for_each_possible_cpu(c) { \		for (i = 0; stats_list[i].name; i++) \			buff64[i] += snmp_get_cpu_field64( \					mib_statistic, \					c, stats_list[i].entry, \					offset); \	} \} #define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \{ \	int i, c; \	for_each_possible_cpu(c) { \		for (i = 0; stats_list[i].name; i++) \			buff[i] += snmp_get_cpu_field( \						mib_statistic, \						c, stats_list[i].entry); \	} \} void inet_get_local_port_range(struct net *net, int *low, int *high); #ifdef CONFIG_SYSCTLstatic inline bool inet_is_local_reserved_port(struct net *net, unsigned short port){	if (!net->ipv4.sysctl_local_reserved_ports)		return false;	return test_bit(port, net->ipv4.sysctl_local_reserved_ports);} static inline bool sysctl_dev_name_is_allowed(const char *name){	return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;} static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port){	return port < net->ipv4.sysctl_ip_prot_sock;} #elsestatic inline bool inet_is_local_reserved_port(struct net *net, unsigned short port){	return false;} static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port){	return port < PROT_SOCK;}#endif __be32 inet_current_timestamp(void); /* From inetpeer.c */extern int inet_peer_threshold;extern int inet_peer_minttl;extern int inet_peer_maxttl; void ipfrag_init(void); void ip_static_sysctl_init(void); #define IP4_REPLY_MARK(net, mark) \	((net)->ipv4.sysctl_fwmark_reflect ? (mark) : 0) static inline bool ip_is_fragment(const struct iphdr *iph){	return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;} #ifdef CONFIG_INET#include <net/dst.h> /* The function in 2.2 was invalid, producing wrong result for * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */static inlineint ip_decrease_ttl(struct iphdr *iph){	u32 check = (__force u32)iph->check;	check += (__force u32)htons(0x0100);	iph->check = (__force __sum16)(check + (check>=0xFFFF));	return --iph->ttl;} static inline int ip_mtu_locked(const struct dst_entry *dst){	const struct rtable *rt = (const struct rtable *)dst; 	return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);} static inlineint ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst){	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc); 	return  pmtudisc == IP_PMTUDISC_DO ||		(pmtudisc == IP_PMTUDISC_WANT &&		 !ip_mtu_locked(dst));} static inline bool ip_sk_accept_pmtu(const struct sock *sk){	return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE &&	       inet_sk(sk)->pmtudisc != IP_PMTUDISC_OMIT;} static inline bool ip_sk_use_pmtu(const struct sock *sk){	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;} static inline bool ip_sk_ignore_df(const struct sock *sk){	return inet_sk(sk)->pmtudisc < IP_PMTUDISC_DO ||	       inet_sk(sk)->pmtudisc == IP_PMTUDISC_OMIT;} static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,						    bool forwarding){	struct net *net = dev_net(dst->dev);	unsigned int mtu; 	if (net->ipv4.sysctl_ip_fwd_use_pmtu ||	    ip_mtu_locked(dst) ||	    !forwarding)		return dst_mtu(dst); 	/* 'forwarding = true' case should always honour route mtu */	mtu = dst_metric_raw(dst, RTAX_MTU);	if (mtu)		return mtu; 	return min(READ_ONCE(dst->dev->mtu), IP_MAX_MTU);} static inline unsigned int ip_skb_dst_mtu(struct sock *sk,					  const struct sk_buff *skb){	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);	} 	return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);} struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,					int fc_mx_len,					struct netlink_ext_ack *extack);static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics){	if (fib_metrics != &dst_default_metrics &&	    refcount_dec_and_test(&fib_metrics->refcnt))		kfree(fib_metrics);} /* ipv4 and ipv6 both use refcounted metrics if it is not the default */static inlinevoid ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics){	dst_init_metrics(dst, fib_metrics->metrics, true); 	if (fib_metrics != &dst_default_metrics) {		dst->_metrics |= DST_METRICS_REFCOUNTED;		refcount_inc(&fib_metrics->refcnt);	}} static inlinevoid ip_dst_metrics_put(struct dst_entry *dst){	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst); 	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))		kfree(p);} u32 ip_idents_reserve(u32 hash, int segs);void __ip_select_ident(struct net *net, struct iphdr *iph, int segs); static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,

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