file的定義

struct file {
    /*
     * fu_list becomes invalid after file_free is called and queued via
     * fu_rcuhead for RCU freeing
     */
    union {
        struct list_head    fu_list;
        struct rcu_head     fu_rcuhead;
    } f_u;
    struct path     f_path;
#define f_dentry    f_path.dentry
#define f_vfsmnt    f_path.mnt
    const struct file_operations    *f_op;
    atomic_t        f_count;
    unsigned int        f_flags;    // O_NONBLOCK等標誌
    mode_t          f_mode;
    loff_t          f_pos;
    struct fown_struct  f_owner;
    unsigned int        f_uid, f_gid;
    struct file_ra_state    f_ra;

    u64         f_version;
#ifdef CONFIG_SECURITY
    void            *f_security;
#endif
    /* needed for tty driver, and maybe others */
    void            *private_data;

#ifdef CONFIG_EPOLL
    /* Used by fs/eventpoll.c to link all the hooks to this file */
    struct list_head    f_ep_links;
    spinlock_t      f_ep_lock;
#endif /* #ifdef CONFIG_EPOLL */
    struct address_space    *f_mapping;
};
 

socket的定義

struct proto_ops {
    int     family;
    struct module   *owner;
    int     (*release)   (struct socket *sock);
    int     (*bind)      (struct socket *sock,
                      struct sockaddr *myaddr,
                      int sockaddr_len);
    int     (*connect)   (struct socket *sock,
                      struct sockaddr *vaddr,
                      int sockaddr_len, int flags);
    int     (*socketpair)(struct socket *sock1,
                      struct socket *sock2);
    int     (*accept)    (struct socket *sock,
                      struct socket *newsock, int flags);
    int     (*getname)   (struct socket *sock,
                      struct sockaddr *addr,
                      int *sockaddr_len, int peer);
    unsigned int    (*poll)      (struct file *file, struct socket *sock,
                      struct poll_table_struct *wait);
    int     (*ioctl)     (struct socket *sock, unsigned int cmd,
                      unsigned long arg);
    int     (*compat_ioctl) (struct socket *sock, unsigned int cmd,
                      unsigned long arg);
    int     (*listen)    (struct socket *sock, int len);
    int     (*shutdown)  (struct socket *sock, int flags);
    int     (*setsockopt)(struct socket *sock, int level,
                      int optname, char __user *optval, int optlen);
    int     (*getsockopt)(struct socket *sock, int level,
                      int optname, char __user *optval, int __user *optlen);
    int     (*compat_setsockopt)(struct socket *sock, int level,
                      int optname, char __user *optval, int optlen);
    int     (*compat_getsockopt)(struct socket *sock, int level,
                      int optname, char __user *optval, int __user *optlen);
    int     (*sendmsg)   (struct kiocb *iocb, struct socket *sock,
                      struct msghdr *m, size_t total_len);
    int     (*recvmsg)   (struct kiocb *iocb, struct socket *sock,
                      struct msghdr *m, size_t total_len,
                      int flags);
    int     (*mmap)      (struct file *file, struct socket *sock,
                      struct vm_area_struct * vma);
    ssize_t     (*sendpage)  (struct socket *sock, struct page *page,
                      int offset, size_t size, int flags);
};

struct socket {
    socket_state        state;    // 
    unsigned long       flags;     // MSG_DONTWAIT等標誌
    const struct proto_ops  *ops;    // 這是啥？
    struct fasync_struct    *fasync_list;
    struct file     *file;    // 關聯文件
    struct sock     *sk;
    wait_queue_head_t   wait;
    short           type;
};
 

Linux socket send解析