text: /*
   * 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 inet_sock
   *
   * Authors:	Many, reorganised here by
   * 		Arnaldo Carvalho de Melo <acme@mandriva.com>
   *
   *		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 _INET_SOCK_H
  #define _INET_SOCK_H
  
  #include <linux/bitops.h>
  #include <linux/string.h>
  #include <linux/types.h>
  #include <linux/jhash.h>
  #include <linux/netdevice.h>
  
  #include <net/flow.h>
  #include <net/sock.h>
  #include <net/request_sock.h>
  #include <net/netns/hash.h>
  #include <net/tcp_states.h>
  #include <net/l3mdev.h>
  
  /** struct ip_options - IP Options
   *
   * @faddr - Saved first hop address
   * @nexthop - Saved nexthop address in LSRR and SSRR
   * @is_strictroute - Strict source route
   * @srr_is_hit - Packet destination addr was our one
   * @is_changed - IP checksum more not valid
   * @rr_needaddr - Need to record addr of outgoing dev
   * @ts_needtime - Need to record timestamp
   * @ts_needaddr - Need to record addr of outgoing dev
   */
  struct ip_options {
  	__be32		faddr;
  	__be32		nexthop;
  	unsigned char	optlen;
  	unsigned char	srr;
  	unsigned char	rr;
  	unsigned char	ts;
  	unsigned char	is_strictroute:1,
  			srr_is_hit:1,
  			is_changed:1,
  			rr_needaddr:1,
  			ts_needtime:1,
  			ts_needaddr:1;
  	unsigned char	router_alert;
  	unsigned char	cipso;
  	unsigned char	__pad2;
  	unsigned char	__data[0];
  };
  
  struct ip_options_rcu {
  	struct rcu_head rcu;
  	struct ip_options opt;
  };
  
  struct ip_options_data {
  	struct ip_options_rcu	opt;
  	char			data[40];
  };
  
  struct inet_request_sock {
  	struct request_sock	req;
  #define ir_loc_addr		req.__req_common.skc_rcv_saddr
  #define ir_rmt_addr		req.__req_common.skc_daddr
  #define ir_num			req.__req_common.skc_num
  #define ir_rmt_port		req.__req_common.skc_dport
  #define ir_v6_rmt_addr		req.__req_common.skc_v6_daddr
  #define ir_v6_loc_addr		req.__req_common.skc_v6_rcv_saddr
  #define ir_iif			req.__req_common.skc_bound_dev_if
  #define ir_cookie		req.__req_common.skc_cookie
  #define ireq_net		req.__req_common.skc_net
  #define ireq_state		req.__req_common.skc_state
  #define ireq_family		req.__req_common.skc_family
  
  	u16			snd_wscale : 4,
  				rcv_wscale : 4,
  				tstamp_ok  : 1,
  				sack_ok	   : 1,
  				wscale_ok  : 1,
  				ecn_ok	   : 1,
  				acked	   : 1,
  				no_srccheck: 1,
  				smc_ok	   : 1;
  	u32                     ir_mark;
  	union {
  		struct ip_options_rcu __rcu	*ireq_opt;
  #if IS_ENABLED(CONFIG_IPV6)
  		struct {
  			struct ipv6_txoptions	*ipv6_opt;
  			struct sk_buff		*pktopts;
  		};
  #endif
  	};
  };
  
  static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
  {
  	return (struct inet_request_sock *)sk;
  }
  
  static inline u32 inet_request_mark(const struct sock *sk, struct sk_buff *skb)
  {
  	if (!sk->sk_mark && sock_net(sk)->ipv4.sysctl_tcp_fwmark_accept)
  		return skb->mark;
  
  	return sk->sk_mark;
  }
  
  static inline int inet_request_bound_dev_if(const struct sock *sk,
  					    struct sk_buff *skb)
  {
  #ifdef CONFIG_NET_L3_MASTER_DEV
  	struct net *net = sock_net(sk);
  
  	if (!sk->sk_bound_dev_if && net->ipv4.sysctl_tcp_l3mdev_accept)
  		return l3mdev_master_ifindex_by_index(net, skb->skb_iif);
  #endif
  
  	return sk->sk_bound_dev_if;
  }
  
  struct inet_cork {
  	unsigned int		flags;
  	__be32			addr;
  	struct ip_options	*opt;
  	unsigned int		fragsize;
  	int			length; /* Total length of all frames */
  	struct dst_entry	*dst;
  	u8			tx_flags;
  	__u8			ttl;
  	__s16			tos;
  	char			priority;
  	__u16			gso_size;
  	u64			transmit_time;
  };
  
  struct inet_cork_full {
  	struct inet_cork	base;
  	struct flowi		fl;
  };
  
  struct ip_mc_socklist;
  struct ipv6_pinfo;
  struct rtable;
  
  /** struct inet_sock - representation of INET sockets
   *
   * @sk - ancestor class
   * @pinet6 - pointer to IPv6 control block
   * @inet_daddr - Foreign IPv4 addr
   * @inet_rcv_saddr - Bound local IPv4 addr
   * @inet_dport - Destination port
   * @inet_num - Local port
   * @inet_saddr - Sending source
   * @uc_ttl - Unicast TTL
   * @inet_sport - Source port
   * @inet_id - ID counter for DF pkts
   * @tos - TOS
   * @mc_ttl - Multicasting TTL
   * @is_icsk - is this an inet_connection_sock?
   * @uc_index - Unicast outgoing device index
   * @mc_index - Multicast device index
   * @mc_list - Group array
   * @cork - info to build ip hdr on each ip frag while socket is corked
   */
  struct inet_sock {
  	/* sk and pinet6 has to be the first two members of inet_sock */
  	struct sock		sk;
  #if IS_ENABLED(CONFIG_IPV6)
  	struct ipv6_pinfo	*pinet6;
  #endif
  	/* Socket demultiplex comparisons on incoming packets. */
  #define inet_daddr		sk.__sk_common.skc_daddr
  #define inet_rcv_saddr		sk.__sk_common.skc_rcv_saddr
  #define inet_dport		sk.__sk_common.skc_dport
  #define inet_num		sk.__sk_common.skc_num
  
  	__be32			inet_saddr;
  	__s16			uc_ttl;
  	__u16			cmsg_flags;
  	__be16			inet_sport;
  	__u16			inet_id;
  
  	struct ip_options_rcu __rcu	*inet_opt;
  	int			rx_dst_ifindex;
  	__u8			tos;
  	__u8			min_ttl;
  	__u8			mc_ttl;
  	__u8			pmtudisc;
  	__u8			recverr:1,
  				is_icsk:1,
  				freebind:1,
  				hdrincl:1,
  				mc_loop:1,
  				transparent:1,
  				mc_all:1,
  				nodefrag:1;
  	__u8			bind_address_no_port:1,
  				defer_connect:1; /* Indicates that fastopen_connect is set
  						  * and cookie exists so we defer connect
  						  * until first data frame is written
  						  */
  	__u8			rcv_tos;
  	__u8			convert_csum;
  	int			uc_index;
  	int			mc_index;
  	__be32			mc_addr;
  	struct ip_mc_socklist __rcu	*mc_list;
  	struct inet_cork_full	cork;
  };
  
  #define IPCORK_OPT	1	/* ip-options has been held in ipcork.opt */
  #define IPCORK_ALLFRAG	2	/* always fragment (for ipv6 for now) */
  
  /* cmsg flags for inet */
  #define IP_CMSG_PKTINFO		BIT(0)
  #define IP_CMSG_TTL		BIT(1)
  #define IP_CMSG_TOS		BIT(2)
  #define IP_CMSG_RECVOPTS	BIT(3)
  #define IP_CMSG_RETOPTS		BIT(4)
  #define IP_CMSG_PASSSEC		BIT(5)
  #define IP_CMSG_ORIGDSTADDR	BIT(6)
  #define IP_CMSG_CHECKSUM	BIT(7)
  #define IP_CMSG_RECVFRAGSIZE	BIT(8)
  
  /**
   * sk_to_full_sk - Access to a full socket
   * @sk: pointer to a socket
   *
   * SYNACK messages might be attached to request sockets.
   * Some places want to reach the listener in this case.
   */
  static inline struct sock *sk_to_full_sk(struct sock *sk)
  {
  #ifdef CONFIG_INET
  	if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
  		sk = inet_reqsk(sk)->rsk_listener;
  #endif
  	return sk;
  }
  
  /* sk_to_full_sk() variant with a const argument */
  static inline const struct sock *sk_const_to_full_sk(const struct sock *sk)
  {
  #ifdef CONFIG_INET
  	if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
  		sk = ((const struct request_sock *)sk)->rsk_listener;
  #endif
  	return sk;
  }
  
  static inline struct sock *skb_to_full_sk(const struct sk_buff *skb)
  {
  	return sk_to_full_sk(skb->sk);
  }
  
  static inline struct inet_sock *inet_sk(const struct sock *sk)
  {
  	return (struct inet_sock *)sk;
  }
  
  static inline void __inet_sk_copy_descendant(struct sock *sk_to,
  					     const struct sock *sk_from,
  					     const int ancestor_size)
  {
  	memcpy(inet_sk(sk_to) + 1, inet_sk(sk_from) + 1,
  	       sk_from->sk_prot->obj_size - ancestor_size);
  }
  #if !(IS_ENABLED(CONFIG_IPV6))
  static inline void inet_sk_copy_descendant(struct sock *sk_to,
  					   const struct sock *sk_from)
  {
  	__inet_sk_copy_descendant(sk_to, sk_from, sizeof(struct inet_sock));
  }
  #endif
  
  int inet_sk_rebuild_header(struct sock *sk);
  
  /**
   * inet_sk_state_load - read sk->sk_state for lockless contexts
   * @sk: socket pointer
   *
   * Paired with inet_sk_state_store(). Used in places we don't hold socket lock:
   * tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...
   */
  static inline int inet_sk_state_load(const struct sock *sk)
  {
  	/* state change might impact lockless readers. */
  	return smp_load_acquire(&sk->sk_state);
  }
  
  /**
   * inet_sk_state_store - update sk->sk_state
   * @sk: socket pointer
   * @newstate: new state
   *
   * Paired with inet_sk_state_load(). Should be used in contexts where
   * state change might impact lockless readers.
   */
  void inet_sk_state_store(struct sock *sk, int newstate);
  
  void inet_sk_set_state(struct sock *sk, int state);
  
  static inline unsigned int __inet_ehashfn(const __be32 laddr,
  					  const __u16 lport,
  					  const __be32 faddr,
  					  const __be16 fport,
  					  u32 initval)
  {
  	return jhash_3words((__force __u32) laddr,
  			    (__force __u32) faddr,
  			    ((__u32) lport) << 16 | (__force __u32)fport,
  			    initval);
  }
  
  struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
  				      struct sock *sk_listener,
  				      bool attach_listener);
  
  static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
  {
  	__u8 flags = 0;
  
  	if (inet_sk(sk)->transparent || inet_sk(sk)->hdrincl)
  		flags |= FLOWI_FLAG_ANYSRC;
  	return flags;
  }
  
  static inline void inet_inc_convert_csum(struct sock *sk)
  {
  	inet_sk(sk)->convert_csum++;
  }
  
  static inline void inet_dec_convert_csum(struct sock *sk)
  {
  	if (inet_sk(sk)->convert_csum > 0)
  		inet_sk(sk)->convert_csum--;
  }
  
  static inline bool inet_get_convert_csum(struct sock *sk)
  {
  	return !!inet_sk(sk)->convert_csum;
  }
  
  
  static inline bool inet_can_nonlocal_bind(struct net *net,
  					  struct inet_sock *inet)
  {
  	return net->ipv4.sysctl_ip_nonlocal_bind ||
  		inet->freebind || inet->transparent;
  }
  
  #endif	/* _INET_SOCK_H */
  