Linux核心数据结构--sock

包含BSD套接口的协议相关信息。例如对于一个INET（Internet Address Domain）套接口此数据结构 包含TCP/IP和UDP/IP信息。

struct sock

{
    /* This must be first. */

    struct sock             *sklist_next;

    struct sock             *sklist_prev;



    struct options          *opt;

    atomic_t                wmem_alloc;

    atomic_t                rmem_alloc;

    unsigned long           allocation;       /* Allocation mode */

    __u32                   write_seq;

    __u32                   sent_seq;

    __u32                   acked_seq;

    __u32                   copied_seq;

    __u32                   rcv_ack_seq;

    unsigned short          rcv_ack_cnt;      /* count of same ack */

   __u32                   window_seq;

    __u32                   fin_seq;

    __u32                   urg_seq;

    __u32                   urg_data;

    __u32                   syn_seq;

    int                     users;            /* user count */

  /*

   *    Not all are volatile, but some are, so we

   *     might as well say they all are.

   */

    volatile char           dead,

                            urginline,

                            intr,

                            blog,

                            done,

                            reuse,

                            keepopen,

                            linger,

                            delay_acks,

                            destroy,

                            ack_timed,

                            no_check,

                            zapped,

                            broadcast,

                            nonagle,

                            bsdism;

    unsigned long           lingertime;

    int                     proc;



    struct sock             *next;

    struct sock             **pprev;

    struct sock             *bind_next;

    struct sock             **bind_pprev;

    struct sock             *pair;

    int                     hashent;

    struct sock             *prev;

    struct sk_buff          *volatile send_head;

    struct sk_buff          *volatile send_next;

    struct sk_buff          *volatile send_tail;

    struct sk_buff_head     back_log;

    struct sk_buff          *partial;

    struct timer_list       partial_timer;

    long                    retransmits;

    struct sk_buff_head     write_queue,

                            receive_queue;

    struct proto            *prot;

    struct wait_queue       **sleep;

    __u32                   daddr;    __u32                   saddr;            /* Sending source */

   __u32                   rcv_saddr;        /* Bound address */

    unsigned short          max_unacked;

    unsigned short          window;

    __u32                   lastwin_seq;      /* sequence number when we last

                                                 updated the window we offer */
   __u32                   high_seq;         /* sequence number when we did

                                                 current fast retransmit */

    volatile unsigned long  ato;              /* ack timeout */

    volatile unsigned long  lrcvtime;         /* jiffies at last data rcv */

    volatile unsigned long  idletime;         /* jiffies at last rcv */

    unsigned int            bytes_rcv;
/*

*    mss is min(mtu, max_window)

*/

    unsigned short          mtu;              /* mss negotiated in the syn's */

    volatile unsigned short mss;              /* current eff. mss - can change */

    volatile unsigned short user_mss;         /* mss requested by user in ioctl */

    volatile unsigned short max_window;

    unsigned long           window_clamp;

    unsigned int            ssthresh;

    unsigned short          num;

    volatile unsigned short cong_window;

    volatile unsigned short cong_count;

    volatile unsigned short packets_out;

    volatile unsigned short shutdown;

    volatile unsigned long  rtt;

    volatile unsigned long  mdev;

    volatile unsigned long  rto;



    volatile unsigned short backoff;

    int                     err, err_soft;    /* Soft holds errors that don't

                                                 cause failure but are the cause

                                                 of a persistent failure not

                                                 just 'timed out' */

    unsigned char           protocol;

    volatile unsigned char  state;

    unsigned char           ack_backlog;

    unsigned char           max_ack_backlog;

    unsigned char           priority;

    unsigned char           debug;

    int                     rcvbuf;

    int                     sndbuf;

    unsigned short          type;

    unsigned char           localroute;       /* Route locally only */

/*

*    This is where all the private (optional) areas that don't

*    overlap will eventually live.

*/

    union

    {

          struct unix_opt   af_unix;

#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)

        struct atalk_sock   af_at;

#endif

#if defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)

        struct ipx_opt      af_ipx;

#endif

#ifdef CONFIG_INET

        struct inet_packet_opt  af_packet;

#ifdef CONFIG_NUTCP       

        struct tcp_opt      af_tcp;

#endif       

#endif

    } protinfo;          /*

*    IP 'private area'

*/

    int                     ip_ttl;           /* TTL setting */

   int                     ip_tos;           /* TOS */

    struct tcphdr           dummy_th;

    struct timer_list       keepalive_timer;  /* TCP keepalive hack */

    struct timer_list       retransmit_timer; /* TCP retransmit timer */

    struct timer_list       delack_timer;     /* TCP delayed ack timer */

    int                     ip_xmit_timeout;  /* Why the timeout is running */

    struct rtable           *ip_route_cache;  /* Cached output route */

    unsigned char           ip_hdrincl;       /* Include headers ? */

#ifdef CONFIG_IP_MULTICAST 

    int                     ip_mc_ttl;        /* Multicasting TTL */

    int                     ip_mc_loop;       /* Loopback */

    char                    ip_mc_name[MAX_ADDR_LEN]; /* Multicast device name */

    struct ip_mc_socklist   *ip_mc_list;      /* Group array */

#endif 



/*

*    This part is used for the timeout functions (timer.c).

*/

    int                      timeout;         /* What are we waiting for? */

    struct timer_list        timer;           /* This is the TIME_WAIT/receive

                                               * timer when we are doing IP

                                               */

    struct timeval           stamp;

/*

  *    Identd

  */

    struct socket            *socket;

  /*

   *    Callbacks

   */

    void                     (*state_change)(struct sock *sk);

    void                     (*data_ready)(struct sock *sk,int bytes);

    void                     (*write_space)(struct sock *sk);

    void                     (*error_report)(struct sock *sk);

 

};