/* 这个和pipe功能有相似之处，pipe是单工的，socketpair是双工的
 * family只能是UNIX域的。
 */
static int
sock_socketpair(int family, int type, int protocol, unsigned long usockvec[2])
{
  int fd1, fd2, i;
  struct socket *sock1, *sock2;
  int er;

  DPRINTF((net_debug,
	"NET: sock_socketpair: family = %d, type = %d, protocol = %d\n",
							family, type, protocol));

  /*
   * Obtain the first socket and check if the underlying protocol
   * supports the socketpair call.
   */
  /* 如果创建失败，则直接返回 */
  if ((fd1 = sock_socket(family, type, protocol)) < 0) return(fd1);
  sock1 = sockfd_lookup(fd1, NULL);
  if (!sock1->ops->socketpair) {
	sys_close(fd1);
	return(-EINVAL);
  }

  /* Now grab another socket and try to connect the two together. */
  if ((fd2 = sock_socket(family, type, protocol)) < 0) {
	sys_close(fd1);
	return(-EINVAL);
  }
  sock2 = sockfd_lookup(fd2, NULL);
  if ((i = sock1->ops->socketpair(sock1, sock2)) < 0) {
	sys_close(fd1);
	sys_close(fd2);
	return(i);
  }
  sock1->conn = sock2;
  sock2->conn = sock1;
  /* 完成socketpair操作后，则这只套接字的状态为连接状态 */
  sock1->state = SS_CONNECTED;
  sock2->state = SS_CONNECTED;

  er=verify_area(VERIFY_WRITE, usockvec, 2 * sizeof(int));
  if(er)
  	return er;
  put_fs_long(fd1, &usockvec[0]);
  put_fs_long(fd2, &usockvec[1]);

  return(0);
}

static struct socket *get_raw_socket(int fd)
{
	struct {
		struct sockaddr_ll sa;
		char  buf[MAX_ADDR_LEN];
	} uaddr;
	int uaddr_len = sizeof uaddr, r;
	struct socket *sock = sockfd_lookup(fd, &r);

	if (!sock)
		return ERR_PTR(-ENOTSOCK);

	/* Parameter checking */
	if (sock->sk->sk_type != SOCK_RAW) {
		r = -ESOCKTNOSUPPORT;
		goto err;
	}

	r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
			       &uaddr_len, 0);
	if (r)
		goto err;

	if (uaddr.sa.sll_family != AF_PACKET) {
		r = -EPFNOSUPPORT;
		goto err;
	}
	return sock;
err:
	sockfd_put(sock);
	return ERR_PTR(r);
}

/* 去连接服务器
 * fd是连接套接字的文件描述符
 * uservaddr是服务器地址
 * addrlen地址长度
 */
static int sock_connect(int fd, struct sockaddr *uservaddr, int addrlen)
{
  struct socket *sock;
  struct file *file;
  int i;

  DPRINTF((net_debug, "NET: sock_connect: fd = %d\n", fd));
  if (fd < 0 || fd >= NR_OPEN || (file=current->filp[fd]) == NULL)
								return(-EBADF);
  
  if (!(sock = sockfd_lookup(fd, &file))) return(-ENOTSOCK);
  switch(sock->state) {
	case SS_UNCONNECTED:
		/* This is ok... continue with connect */
		break;
	case SS_CONNECTED:
		/* Socket is already connected */
		return -EISCONN;
	case SS_CONNECTING:
		/* Not yet connected... we will check this. */
		return(sock->ops->connect(sock, uservaddr,
					  addrlen, file->f_flags));
	default:
		DPRINTF((net_debug,
			"NET: sock_connect: socket not unconnected\n"));
		return(-EINVAL);
  }
  /* 开始真正的连接服务器 */
  i = sock->ops->connect(sock, uservaddr, addrlen, file->f_flags);
  if (i < 0) {
	DPRINTF((net_debug, "NET: sock_connect: connect failed\n"));
	return(i);
  }
  return(0);
}

/** Handle some skbs on a varp socket (if any).
 *
 * @param fd socket file descriptor
 * @param n maximum number of skbs to handle
 * @return number of skbs handled
 */
static int handle_varp_sock(int fd, int n){
    int ret = 0;
    int err = 0;
    struct sk_buff *skb;
    struct socket *sock = NULL;

    sock = sockfd_lookup(fd, &err);
    if (!sock){
        wprintf("> no sock for fd=%d\n", fd);
        goto exit;
    }
    for( ; ret < n; ret++){
        if(!sock->sk) break;
        skb = skb_dequeue(&sock->sk->sk_receive_queue);
        if(!skb) break;
        // Call the skb destructor so it isn't charged to the socket anymore.
        // An skb from a socket receive queue is charged to the socket
        // by skb_set_owner_r() until its destructor is called.
        // If the destructor is not called the socket will run out of
        // receive queue space and be unable to accept incoming skbs.
        // The destructor used is sock_rfree(), see 'include/net/sock.h'.
        // Other destructors: sock_wfree, sk_stream_rfree.
        skb_orphan(skb);
        handle_varp_skb(skb);
    }
    sockfd_put(sock);
  exit:
    dprintf("< ret=%d\n", ret);
    return ret;
}

asmlinkage long compat_sys_getsockopt(int fd, int level, int optname,
				char __user *optval, int __user *optlen)
{
	int err;
	struct socket *sock = sockfd_lookup(fd, &err);

	if (sock) {
		err = security_socket_getsockopt(sock, level, optname);
		if (err) {
			sockfd_put(sock);
			return err;
		}

		if (level == SOL_SOCKET)
			err = compat_sock_getsockopt(sock, level,
					optname, optval, optlen);
		else if (sock->ops->compat_getsockopt)
			err = sock->ops->compat_getsockopt(sock, level,
					optname, optval, optlen);
		else
			err = sock->ops->getsockopt(sock, level,
					optname, optval, optlen);
		sockfd_put(sock);
	}
	return err;
}

static int
sock_socketpair(int family, int type, int protocol, int usockvec[2])
{
	int fd1, fd2, i;
	struct socket *sock1, *sock2;

	PRINTK("sys_socketpair: family = %d, type = %d, protocol = %d\n",
	       family, type, protocol);

	/*
	 * obtain the first socket and check if the underlying protocol
	 * supports the socketpair call
	 */
	if ((fd1 = sock_socket(family, type, protocol)) < 0)
		return fd1;
	sock1 = sockfd_lookup(fd1, NULL);
	if (!sock1->ops->socketpair) {
		sys_close(fd1);
		return -EINVAL;
	}

	/*
	 * now grab another socket and try to connect the two together
	 */
	if ((fd2 = sock_socket(family, type, protocol)) < 0) {
		sys_close(fd1);
		return -EINVAL;
	}
	sock2 = sockfd_lookup(fd2, NULL);
	if ((i = sock1->ops->socketpair(sock1, sock2)) < 0) {
		sys_close(fd1);
		sys_close(fd2);
		return i;
	}
	sock1->conn = sock2;
	sock2->conn = sock1;
	sock1->state = SS_CONNECTED;
	sock2->state = SS_CONNECTED;

	verify_area(usockvec, 2 * sizeof(int));
	put_fs_long(fd1, &usockvec[0]);
	put_fs_long(fd2, &usockvec[1]);

	return 0;
}

/* fd是监听的套接字,该函数的执行过程为，首先在sockets数组当中申请一个
 * struct socket，在申请struct socket的过程中就给socket分配了inode节点，
 * 然后在分配一个struct file结构，最后就返回一个新的文件描述符，该过程是一个
 * 反向的过程
 */
static int sock_accept(int fd, struct sockaddr *upeer_sockaddr, int *upeer_addrlen)
{
  struct file *file;
  struct socket *sock, *newsock;
  int i;

  DPRINTF((net_debug, "NET: sock_accept: fd = %d\n", fd));
  if (fd < 0 || fd >= NR_OPEN || ((file = current->filp[fd]) == NULL))
								return(-EBADF);

  /* 找到监听fd的socket结构 */
  if (!(sock = sockfd_lookup(fd, &file))) return(-ENOTSOCK);
  if (sock->state != SS_UNCONNECTED) {
	DPRINTF((net_debug, "NET: sock_accept: socket isn't unconnected\n"));
	return(-EINVAL);
  }
  if (!(sock->flags & SO_ACCEPTCON)) {
	DPRINTF((net_debug,
		"NET: sock_accept: socket not accepting connections!\n"));
	return(-EINVAL);
  }

	/* 非阻塞的获取一个socket结构 */
  if (!(newsock = sock_alloc(0))) {
	printk("NET: sock_accept: no more sockets\n");
	return(-EAGAIN);
  }
  /* 两个socket的类型，协议族操作函数相同 */
  newsock->type = sock->type;
  newsock->ops = sock->ops;
  if ((i = sock->ops->dup(newsock, sock)) < 0) {
	sock_release(newsock);
	return(i);
  }

  i = newsock->ops->accept(sock, newsock, file->f_flags);
  if ( i < 0) {
	sock_release(newsock);
	return(i);
  }

  /* 给新的socket分配一个文件描述符 */
  if ((fd = get_fd(SOCK_INODE(newsock))) < 0) {
	sock_release(newsock);
	return(-EINVAL);
  }

  DPRINTF((net_debug, "NET: sock_accept: connected socket 0x%x via 0x%x\n",
							sock, newsock));

  if (upeer_sockaddr)
	newsock->ops->getname(newsock, upeer_sockaddr, upeer_addrlen, 1);

  /* 返回新的socket文件描述符 */
  return(fd);
}

static int
sock_getpeername(int fd, struct sockaddr *usockaddr, int *usockaddr_len)
{
	struct socket *sock;

	PRINTK("sys_getpeername: fd = %d\n", fd);
	if (!(sock = sockfd_lookup(fd, NULL)))
		return -EBADF;
	return sock->ops->getname(sock, usockaddr, usockaddr_len, 1);
}

static int
sock_getpeername(int fd, struct sockaddr *usockaddr, int *usockaddr_len)
{
  struct socket *sock;

  DPRINTF((net_debug, "NET: sock_getpeername: fd = %d\n", fd));
  if (fd < 0 || fd >= NR_OPEN || current->filp[fd] == NULL)
			return(-EBADF);
  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);
  return(sock->ops->getname(sock, usockaddr, usockaddr_len, 1));
}

static int hidp_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *) arg;
	struct hidp_connadd_req ca;
	struct hidp_conndel_req cd;
	struct hidp_connlist_req cl;
	struct hidp_conninfo ci;
	struct socket *csock;
	struct socket *isock;
	int err;

	BT_DBG("cmd %x arg %lx", cmd, arg);

	switch (cmd) {
	case HIDPCONNADD:
		if (!capable(CAP_NET_ADMIN))
			return -EACCES;

		if (copy_from_user(&ca, argp, sizeof(ca)))
			return -EFAULT;

		csock = sockfd_lookup(ca.ctrl_sock, &err);
		if (!csock)
			return err;

		isock = sockfd_lookup(ca.intr_sock, &err);
		if (!isock) {
			sockfd_put(csock);
			return err;
		}

<<<<<<< HEAD
		if (csock->sk->sk_state != BT_CONNECTED ||
				isock->sk->sk_state != BT_CONNECTED) {
=======
		if (csock->sk->sk_state != BT_CONNECTED || isock->sk->sk_state != BT_CONNECTED) {
>>>>>>> 296c66da8a02d52243f45b80521febece5ed498a
			sockfd_put(csock);
			sockfd_put(isock);
			return -EBADFD;
		}

/** Remove a wait queue from a socket.
 *
 * @param fd socket file descriptor
 * @param waitq queue
 * @return 0 on success, error code otherwise
 */
int sock_remove_wait_queue(int fd, wait_queue_t *waitq){
    int err = -EINVAL;
    struct socket *sock = NULL;

    if(fd < 0) goto exit;
    sock = sockfd_lookup(fd, &err);
    if (!sock) goto exit;
    remove_wait_queue(sock->sk->sk_sleep, waitq);
    sockfd_put(sock);
    err = 0;
  exit:
    return err;
}

/** Set the data ready callback on a socket.
 */
int sock_set_callback(int fd){
    int err = -EINVAL;
    struct socket *sock = NULL;

    if(fd < 0) goto exit;
    sock = sockfd_lookup(fd, &err);
    if (!sock) goto exit;
    sock->sk->sk_data_ready = sock_data_ready;
    sockfd_put(sock);
    err = 0;
  exit:
    return err;
}

static int hone_ioctl(struct inode *inode, struct file *file,
		unsigned int num, unsigned long param)
#endif
{
	struct hone_reader *reader = file->private_data;
	int err;

	if (_IOC_TYPE(num) != 0xE0)
		return -EINVAL;

	switch (num) {
	case HEIO_RESTART:
		atomic_set_mask(READER_RESTART, &reader->flags);
		wake_up_interruptible_all(&reader->event_wait_queue);
		return 0;
	case HEIO_GET_AT_HEAD:
		return atomic_read(&reader->flags) & READER_HEAD ? 1 : 0;
	case HEIO_GET_SNAPLEN:
		return put_user(reader->info.snaplen, (unsigned int __user *) param);
	case HEIO_SET_SNAPLEN:
		reader->info.snaplen = (unsigned int) param;
		atomic_set_mask(READER_HEAD, &reader->flags);
		return 0;
	case HEIO_SET_FILTER_SOCK:
	{
		int fd = (int) param;
		struct sock *sk;
		if (fd != -1) {
			struct socket *sock;
			if (!(sock = sockfd_lookup(fd, &err)))
				return err;
			sk = sock->sk;
			sock_hold(sk);
			fput(sock->file);
		} else {
			sk = NULL;
		}
		for (;;) {
			struct sock *old_sk = reader->filter_sk;
			if (cmpxchg(&reader->filter_sk, old_sk, sk) == old_sk) {
				if (old_sk)
					sock_put(old_sk);
				break;
			}
		}
		return 0;
	}
	}

	return -EINVAL;
}

/*
 * for accept, we attempt to create a new socket, set up the link with the
 * client, wake up the client, then return the new connected fd.
 */
static int
sock_accept(int fd, struct sockaddr *upeer_sockaddr, int *upeer_addrlen)
{
	struct file *file;
	struct socket *sock, *newsock;
	int i;

	PRINTK("sys_accept: fd = %d\n", fd);
	if (!(sock = sockfd_lookup(fd, &file)))
		return -EBADF;
	if (sock->state != SS_UNCONNECTED) {
		PRINTK("sys_accept: socket isn't unconnected\n");
		return -EINVAL;
	}
	if (!(sock->flags & SO_ACCEPTCON)) {
		PRINTK("sys_accept: socket not accepting connections!\n");
		return -EINVAL;
	}

	if (!(newsock = sock_alloc(0))) {
		printk("sys_accept: no more sockets\n");
		return -EAGAIN;
	}
	newsock->type = sock->type;
	newsock->ops = sock->ops;
	if ((i = sock->ops->dup(newsock, sock)) < 0) {
		sock_release(newsock);
		return i;
	}

	if ((fd = get_fd(SOCK_INODE(newsock))) < 0) {
		sock_release(newsock);
		return -EINVAL;
	}
	i = newsock->ops->accept(sock, newsock, file->f_flags);

	if ( i < 0)
	  {
	     sys_close (fd);
	     return (i);
	  }

	PRINTK("sys_accept: connected socket 0x%x via 0x%x\n",
	       sock, newsock);

	if (upeer_sockaddr)
		newsock->ops->getname(newsock, upeer_sockaddr,
				      upeer_addrlen, 1);

	return fd;
}

/*
 * binds a name to a socket. nothing much to do here since its the
 * protocol's responsibility to handle the local address
 */
static int
sock_bind(int fd, struct sockaddr *umyaddr, int addrlen)
{
	struct socket *sock;
	int i;

	PRINTK("sys_bind: fd = %d\n", fd);
	if (!(sock = sockfd_lookup(fd, NULL)))
		return -EBADF;
	if ((i = sock->ops->bind(sock, umyaddr, addrlen)) < 0) {
		PRINTK("sys_bind: bind failed\n");
		return i;
	}
	return 0;
}

/* 关闭套接字 */
static int
sock_shutdown(int fd, int how)
{
  struct socket *sock;
  struct file *file;

  DPRINTF((net_debug, "NET: sock_shutdown(fd = %d, how = %d)\n", fd, how));

  if (fd < 0 || fd >= NR_OPEN || ((file = current->filp[fd]) == NULL))
								return(-EBADF);

  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);

  return(sock->ops->shutdown(sock, how));
}

static int sock_send(int fd, void * buff, int len, unsigned flags)
{
  struct socket *sock;
  struct file *file;

  DPRINTF((net_debug,
	"NET: sock_send(fd = %d, buff = %X, len = %d, flags = %X)\n",
       							fd, buff, len, flags));

  if (fd < 0 || fd >= NR_OPEN || ((file = current->filp[fd]) == NULL))
								return(-EBADF);
  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);

  return(sock->ops->send(sock, buff, len, (file->f_flags & O_NONBLOCK), flags));
}

/*
 * Bind a name to a socket. Nothing much to do here since its
 * the protocol's responsibility to handle the local address.
 */
static int
sock_bind(int fd, struct sockaddr *umyaddr, int addrlen)
{
  struct socket *sock;
  int i;

  DPRINTF((net_debug, "NET: sock_bind: fd = %d\n", fd));
  if (fd < 0 || fd >= NR_OPEN || current->filp[fd] == NULL)
								return(-EBADF);
  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);
  if ((i = sock->ops->bind(sock, umyaddr, addrlen)) < 0) {
	DPRINTF((net_debug, "NET: sock_bind: bind failed\n"));
	return(i);
  }
  return(0);
}

static int
sock_setsockopt(int fd, int level, int optname, char *optval, int optlen)
{
  struct socket *sock;
  struct file *file;
	
  DPRINTF((net_debug, "NET: sock_setsockopt(fd=%d, level=%d, optname=%d,\n",
							fd, level, optname));
  DPRINTF((net_debug, "                     optval = %X, optlen = %d)\n",
							optval, optlen));

  if (fd < 0 || fd >= NR_OPEN || ((file = current->filp[fd]) == NULL))
								return(-EBADF);
  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);

  return(sock->ops->setsockopt(sock, level, optname, optval, optlen));
}

/*
 * Perform a listen. Basically, we allow the protocol to do anything
 * necessary for a listen, and if that works, we mark the socket as
 * ready for listening.
 */
static int
sock_listen(int fd, int backlog)
{
  struct socket *sock;

  DPRINTF((net_debug, "NET: sock_listen: fd = %d\n", fd));
  if (fd < 0 || fd >= NR_OPEN || current->filp[fd] == NULL)
								return(-EBADF);
  if (!(sock = sockfd_lookup(fd, NULL))) return(-ENOTSOCK);
  if (sock->state != SS_UNCONNECTED) {
	DPRINTF((net_debug, "NET: sock_listen: socket isn't unconnected\n"));
	return(-EINVAL);
  }
  if (sock->ops && sock->ops->listen) sock->ops->listen(sock, backlog);
  sock->flags |= SO_ACCEPTCON;
  return(0);
}