/*
 *  linux/fs/ncpfs/sock.c
 *
 *  Copyright (C) 1992, 1993  Rick Sladkey
 *
 *  Modified 1995, 1996 by Volker Lendecke to be usable for ncp
 *
 */

#include <linux/sched.h>
#include <linux/ncp_fs.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/mm.h>
#include <linux/netdevice.h>
#include <net/scm.h>
#include <linux/ipx.h>

#include <linux/ncp.h>
#include <linux/ncp_fs.h>
#include <linux/ncp_fs_sb.h>
#include <net/sock.h>
#include <linux/poll.h>

static int _recv(struct socket *sock, unsigned char *ubuf, int size,
		 unsigned flags)
{
	struct iovec iov;
	struct msghdr msg;
	struct scm_cookie scm;

	memset(&scm, 0, sizeof(scm));

	iov.iov_base = ubuf;
	iov.iov_len = size;

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_control = NULL;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	return sock->ops->recvmsg(sock, &msg, size, flags, &scm);
}

static int _send(struct socket *sock, const void *buff, int len)
{
	struct iovec iov;
	struct msghdr msg;
	struct scm_cookie scm;
	int err;

	iov.iov_base = (void *) buff;
	iov.iov_len = len;

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	msg.msg_control = NULL;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_flags = 0;

	err = scm_send(sock, &msg, &scm);
	if (err < 0) {
		return err;
	}
	err = sock->ops->sendmsg(sock, &msg, len, &scm);
	scm_destroy(&scm);
	return err;
}

#define NCP_SLACK_SPACE 1024

#define _S(nr) (1<<((nr)-1))

static int do_ncp_rpc_call(struct ncp_server *server, int size)
{
	struct file *file;
	struct inode *inode;
	struct socket *sock;
	unsigned short fs;
	int result;
	char *start = server->packet;
	poll_table wait_table;
	struct poll_table_entry entry;
	int init_timeout, max_timeout;
	int timeout;
	int retrans;
	int major_timeout_seen;
	int acknowledge_seen;
	int n;
	unsigned long old_mask;

	/* We have to check the result, so store the complete header */
	struct ncp_request_header request =
	*((struct ncp_request_header *) (server->packet));

	struct ncp_reply_header reply;

	file = server->ncp_filp;
	inode = file->f_inode;
	sock = &inode->u.socket_i;
	if (!sock) {
		printk("ncp_rpc_call: socki_lookup failed\n");
		return -EBADF;
	}
	init_timeout = server->m.time_out;
	max_timeout = NCP_MAX_RPC_TIMEOUT;
	retrans = server->m.retry_count;
	major_timeout_seen = 0;
	acknowledge_seen = 0;
	old_mask = current->blocked;
	current->blocked |= ~(_S(SIGKILL)
#if 0
			      | _S(SIGSTOP)
#endif
			      | ((server->m.flags & NCP_MOUNT_INTR)
	       ? ((current->sig->action[SIGINT - 1].sa_handler == SIG_DFL
		   ? _S(SIGINT) : 0)
	       | (current->sig->action[SIGQUIT - 1].sa_handler == SIG_DFL
		  ? _S(SIGQUIT) : 0))
				 : 0));
	fs = get_fs();
	set_fs(get_ds());
	for (n = 0, timeout = init_timeout;; n++, timeout <<= 1) {
		DDPRINTK("ncpfs: %08lX:%02X%02X%02X%02X%02X%02X:%04X\n",
			 htonl(server->m.serv_addr.sipx_network),
			 server->m.serv_addr.sipx_node[0],
			 server->m.serv_addr.sipx_node[1],
			 server->m.serv_addr.sipx_node[2],
			 server->m.serv_addr.sipx_node[3],
			 server->m.serv_addr.sipx_node[4],
			 server->m.serv_addr.sipx_node[5],
			 ntohs(server->m.serv_addr.sipx_port));
		DDPRINTK("ncpfs: req.typ: %04X, con: %d, "
			 "seq: %d",
			 request.type,
			 (request.conn_high << 8) + request.conn_low,
			 request.sequence);
		DDPRINTK(" func: %d\n",
			 request.function);

		result = _send(sock, (void *) start, size);
		if (result < 0) {
			printk("ncp_rpc_call: send error = %d\n", result);
			break;
		}
	      re_select:
		wait_table.nr = 0;
		wait_table.entry = &entry;
		current->state = TASK_INTERRUPTIBLE;
		if (!(file->f_op->poll(file, &wait_table) & POLLIN)) {
			if (timeout > max_timeout) {
				/* JEJB/JSP 2/7/94
				 * This is useful to see if the system is
				 * hanging */
				if (acknowledge_seen == 0) {
					printk("NCP max timeout\n");
				}
				timeout = max_timeout;
			}
			current->timeout = jiffies + timeout;
			schedule();
			remove_wait_queue(entry.wait_address, &entry.wait);
			current->state = TASK_RUNNING;
			if (current->signal & ~current->blocked) {
				current->timeout = 0;
				result = -ERESTARTSYS;
				break;
			}
			if (!current->timeout) {
				if (n < retrans)
					continue;
				if (server->m.flags & NCP_MOUNT_SOFT) {
					printk("NCP server not responding\n");
					result = -EIO;
					break;
				}
				n = 0;
				timeout = init_timeout;
				init_timeout <<= 1;
				if (!major_timeout_seen) {
					printk("NCP server not responding\n");
				}
				major_timeout_seen = 1;
				continue;
			} else
				current->timeout = 0;
		} else if (wait_table.nr)
			remove_wait_queue(entry.wait_address, &entry.wait);
		current->state = TASK_RUNNING;

		/* Get the header from the next packet using a peek, so keep it
		 * on the recv queue.  If it is wrong, it will be some reply
		 * we don't now need, so discard it */
		result = _recv(sock, (void *) &reply, sizeof(reply),
			       MSG_PEEK | MSG_DONTWAIT);
		if (result < 0) {
			if (result == -EAGAIN) {
				DPRINTK("ncp_rpc_call: bad select ready\n");
				goto re_select;
			}
			if (result == -ECONNREFUSED) {
				DPRINTK("ncp_rpc_call: server playing coy\n");
				goto re_select;
			}
			if (result != -ERESTARTSYS) {
				printk("ncp_rpc_call: recv error = %d\n",
				       -result);
			}
			break;
		}
		if ((result == sizeof(reply))
		    && (reply.type == NCP_POSITIVE_ACK)) {
			/* Throw away the packet */
			DPRINTK("ncp_rpc_call: got positive acknowledge\n");
			_recv(sock, (void *) &reply, sizeof(reply),
			      MSG_DONTWAIT);
			n = 0;
			timeout = max_timeout;
			acknowledge_seen = 1;
			goto re_select;
		}
		DDPRINTK("ncpfs: rep.typ: %04X, con: %d, tsk: %d,"
			 "seq: %d\n",
			 reply.type,
			 (reply.conn_high << 8) + reply.conn_low,
			 reply.task,
			 reply.sequence);

		if ((result >= sizeof(reply))
		    && (reply.type == NCP_REPLY)
		    && ((request.type == NCP_ALLOC_SLOT_REQUEST)
			|| ((reply.sequence == request.sequence)
			    && (reply.conn_low == request.conn_low)
/* seem to get wrong task from NW311 && (reply.task      == request.task) */
			    && (reply.conn_high == request.conn_high)))) {
			if (major_timeout_seen)
				printk("NCP server OK\n");
			break;
		}
		/* JEJB/JSP 2/7/94
		 * we have xid mismatch, so discard the packet and start
		 * again.  What a hack! but I can't call recvfrom with
		 * a null buffer yet. */
		_recv(sock, (void *) &reply, sizeof(reply), MSG_DONTWAIT);

		DPRINTK("ncp_rpc_call: reply mismatch\n");
		goto re_select;
	}
	/* 
	 * we have the correct reply, so read into the correct place and
	 * return it
	 */
	result = _recv(sock, (void *) start, server->packet_size, MSG_DONTWAIT);
	if (result < 0) {
		printk("NCP: notice message: result=%d\n", result);
	} else if (result < sizeof(struct ncp_reply_header)) {
		printk("NCP: just caught a too small read memory size..., "
		       "email to NET channel\n");
		printk("NCP: result=%d\n", result);
		result = -EIO;
	}
	current->blocked = old_mask;
	set_fs(fs);
	return result;
}

/*
 * We need the server to be locked here, so check!
 */

static int ncp_do_request(struct ncp_server *server, int size)
{
	int result;

	if (server->lock == 0) {
		printk("ncpfs: Server not locked!\n");
		return -EIO;
	}
	if (!ncp_conn_valid(server)) {
		return -EIO;
	}
	result = do_ncp_rpc_call(server, size);

	DDPRINTK("do_ncp_rpc_call returned %d\n", result);

	if (result < 0) {
		/* There was a problem with I/O, so the connections is
		 * no longer usable. */
		ncp_invalidate_conn(server);
	}
	return result;
}

/* ncp_do_request assures that at least a complete reply header is
 * received. It assumes that server->current_size contains the ncp
 * request size */
int ncp_request(struct ncp_server *server, int function)
{
	struct ncp_request_header *h
	= (struct ncp_request_header *) (server->packet);
	struct ncp_reply_header *reply
	= (struct ncp_reply_header *) (server->packet);

	int request_size = server->current_size
	- sizeof(struct ncp_request_header);

	int result;

	if (server->has_subfunction != 0) {
		*(__u16 *) & (h->data[0]) = htons(request_size - 2);
	}
	h->type = NCP_REQUEST;

	server->sequence += 1;
	h->sequence = server->sequence;
	h->conn_low = (server->connection) & 0xff;
	h->conn_high = ((server->connection) & 0xff00) >> 8;
	h->task = (current->pid) & 0xff;
	h->function = function;

	if ((result = ncp_do_request(server, request_size + sizeof(*h))) < 0) {
		DPRINTK("ncp_request_error: %d\n", result);
		return result;
	}
	server->completion = reply->completion_code;
	server->conn_status = reply->connection_state;
	server->reply_size = result;
	server->ncp_reply_size = result - sizeof(struct ncp_reply_header);

	result = reply->completion_code;

	if (result != 0) {
		DPRINTK("ncp_completion_code: %x\n", result);
	}
	return result;
}

int ncp_connect(struct ncp_server *server)
{
	struct ncp_request_header *h
	= (struct ncp_request_header *) (server->packet);
	int result;

	h->type = NCP_ALLOC_SLOT_REQUEST;

	server->sequence = 0;
	h->sequence = server->sequence;
	h->conn_low = 0xff;
	h->conn_high = 0xff;
	h->task = (current->pid) & 0xff;
	h->function = 0;

	if ((result = ncp_do_request(server, sizeof(*h))) < 0) {
		return result;
	}
	server->sequence = 0;
	server->connection = h->conn_low + (h->conn_high * 256);
	return 0;
}

int ncp_disconnect(struct ncp_server *server)
{
	struct ncp_request_header *h
	= (struct ncp_request_header *) (server->packet);

	h->type = NCP_DEALLOC_SLOT_REQUEST;

	server->sequence += 1;
	h->sequence = server->sequence;
	h->conn_low = (server->connection) & 0xff;
	h->conn_high = ((server->connection) & 0xff00) >> 8;
	h->task = (current->pid) & 0xff;
	h->function = 0;

	return ncp_do_request(server, sizeof(*h));
}

void ncp_lock_server(struct ncp_server *server)
{
#if 0
	/* For testing, only 1 process */
	if (server->lock != 0) {
		DPRINTK("ncpfs: server locked!!!\n");
	}
#endif
	while (server->lock)
		sleep_on(&server->wait);
	server->lock = 1;
}

void ncp_unlock_server(struct ncp_server *server)
{
	if (server->lock != 1) {
		printk("ncp_unlock_server: was not locked!\n");
	}
	server->lock = 0;
	wake_up(&server->wait);
}