/*
 *  linux/fs/ncpfs/sock.c
 *
 *  Copyright (C) 1992, 1993  Rick Sladkey
 *
 *  Modified 1995, 1996 by Volker Lendecke to be usable for ncp
 *  Modified 1997 Peter Waltenberg, Bill Hawes, David Woodhouse for 2.1 dcache
 *
 */


#include <linux/time.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <asm/uaccess.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/mm.h>
#include <linux/netdevice.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <net/scm.h>
#include <net/sock.h>
#include <linux/ipx.h>
#include <linux/poll.h>
#include <linux/file.h>

#include "ncp_fs.h"

#include "ncpsign_kernel.h"

static int _recv(struct socket *sock, void *buf, int size, unsigned flags)
{
	struct msghdr msg = {NULL, };
	struct kvec iov = {buf, size};
	return kernel_recvmsg(sock, &msg, &iov, 1, size, flags);
}

static inline int do_send(struct socket *sock, struct kvec *vec, int count,
			  int len, unsigned flags)
{
	struct msghdr msg = { .msg_flags = flags };
	return kernel_sendmsg(sock, &msg, vec, count, len);
}

static int _send(struct socket *sock, const void *buff, int len)
{
	struct kvec vec;
	vec.iov_base = (void *) buff;
	vec.iov_len = len;
	return do_send(sock, &vec, 1, len, 0);
}

struct ncp_request_reply {
	struct list_head req;
	wait_queue_head_t wq;
	atomic_t refs;
	unsigned char* reply_buf;
	size_t datalen;
	int result;
	enum { RQ_DONE, RQ_INPROGRESS, RQ_QUEUED, RQ_IDLE, RQ_ABANDONED } status;
	struct kvec* tx_ciov;
	size_t tx_totallen;
	size_t tx_iovlen;
	struct kvec tx_iov[3];
	u_int16_t tx_type;
	u_int32_t sign[6];
};

static inline struct ncp_request_reply* ncp_alloc_req(void)
{
	struct ncp_request_reply *req;

	req = kmalloc(sizeof(struct ncp_request_reply), GFP_KERNEL);
	if (!req)
		return NULL;

	init_waitqueue_head(&req->wq);
	atomic_set(&req->refs, (1));
	req->status = RQ_IDLE;

	return req;
}

static void ncp_req_get(struct ncp_request_reply *req)
{
	atomic_inc(&req->refs);
}

static void ncp_req_put(struct ncp_request_reply *req)
{
	if (atomic_dec_and_test(&req->refs))
		kfree(req);
}

void ncp_tcp_data_ready(struct sock *sk, int len)
{
	struct ncp_server *server = sk->sk_user_data;

	server->data_ready(sk, len);
	schedule_work(&server->rcv.tq);
}

void ncp_tcp_error_report(struct sock *sk)
{
	struct ncp_server *server = sk->sk_user_data;
	
	server->error_report(sk);
	schedule_work(&server->rcv.tq);
}

void ncp_tcp_write_space(struct sock *sk)
{
	struct ncp_server *server = sk->sk_user_data;
	
	/* We do not need any locking: we first set tx.creq, and then we do sendmsg,
	   not vice versa... */
	server->write_space(sk);
	if (server->tx.creq)
		schedule_work(&server->tx.tq);
}

void ncpdgram_timeout_call(unsigned long v)
{
	struct ncp_server *server = (void*)v;
	
	schedule_work(&server->timeout_tq);
}

static inline void ncp_finish_request(struct ncp_server *server, struct ncp_request_reply *req, int result)
{
	req->result = result;
	if (req->status != RQ_ABANDONED)
		memcpy(req->reply_buf, server->rxbuf, req->datalen);
	req->status = RQ_DONE;
	wake_up_all(&req->wq);
	ncp_req_put(req);
}

static void __abort_ncp_connection(struct ncp_server *server)
{
	struct ncp_request_reply *req;

	ncp_invalidate_conn(server);
	del_timer(&server->timeout_tm);
	while (!list_empty(&server->tx.requests)) {
		req = list_entry(server->tx.requests.next, struct ncp_request_reply, req);
		
		list_del_init(&req->req);
		ncp_finish_request(server, req, -EIO);
	}
	req = server->rcv.creq;
	if (req) {
		server->rcv.creq = NULL;
		ncp_finish_request(server, req, -EIO);
		server->rcv.ptr = NULL;
		server->rcv.state = 0;
	}
	req = server->tx.creq;
	if (req) {
		server->tx.creq = NULL;
		ncp_finish_request(server, req, -EIO);
	}
}

static inline int get_conn_number(struct ncp_reply_header *rp)
{
	return rp->conn_low | (rp->conn_high << 8);
}

static inline void __ncp_abort_request(struct ncp_server *server, struct ncp_request_reply *req, int err)
{
	/* If req is done, we got signal, but we also received answer... */
	switch (req->status) {
		case RQ_IDLE:
		case RQ_DONE:
			break;
		case RQ_QUEUED:
			list_del_init(&req->req);
			ncp_finish_request(server, req, err);
			break;
		case RQ_INPROGRESS:
			req->status = RQ_ABANDONED;
			break;
		case RQ_ABANDONED:
			break;
	}
}

static inline void ncp_abort_request(struct ncp_server *server, struct ncp_request_reply *req, int err)
{
	mutex_lock(&server->rcv.creq_mutex);
	__ncp_abort_request(server, req, err);
	mutex_unlock(&server->rcv.creq_mutex);
}

static inline void __ncptcp_abort(struct ncp_server *server)
{
	__abort_ncp_connection(server);
}

static int ncpdgram_send(struct socket *sock, struct ncp_request_reply *req)
{
	struct kvec vec[3];
	/* sock_sendmsg updates iov pointers for us :-( */
	memcpy(vec, req->tx_ciov, req->tx_iovlen * sizeof(vec[0]));
	return do_send(sock, vec, req->tx_iovlen,
		       req->tx_totallen, MSG_DONTWAIT);
}

static void __ncptcp_try_send(struct ncp_server *server)
{
	struct ncp_request_reply *rq;
	struct kvec *iov;
	struct kvec iovc[3];
	int result;

	rq = server->tx.creq;
	if (!rq)
		return;

	/* sock_sendmsg updates iov pointers for us :-( */
	memcpy(iovc, rq->tx_ciov, rq->tx_iovlen * sizeof(iov[0]));
	result = do_send(server->ncp_sock, iovc, rq->tx_iovlen,
			 rq->tx_totallen, MSG_NOSIGNAL | MSG_DONTWAIT);

	if (result == -EAGAIN)
		return;

	if (result < 0) {
		printk(KERN_ERR "ncpfs: tcp: Send failed: %d\n", result);
		__ncp_abort_request(server, rq, result);
		return;
	}
	if (result >= rq->tx_totallen) {
		server->rcv.creq = rq;
		server->tx.creq = NULL;
		return;
	}
	rq->tx_totallen -= result;
	iov = rq->tx_ciov;
	while (iov->iov_len <= result) {
		result -= iov->iov_len;
		iov++;
		rq->tx_iovlen--;
	}
	iov->iov_base += result;
	iov->iov_len -= result;
	rq->tx_ciov = iov;
}

static inline void ncp_init_header(struct ncp_server *server, struct ncp_request_reply *req, struct ncp_request_header *h)
{
	req->status = RQ_INPROGRESS;
	h->conn_low = server->connection;
	h->conn_high = server->connection >> 8;
	h->sequence = ++server->sequence;
}
	
static void ncpdgram_start_request(struct ncp_server *server, struct ncp_request_reply *req)
{
	size_t signlen;
	struct ncp_request_header* h;
	
	req->tx_ciov = req->tx_iov + 1;

	h = req->tx_iov[1].iov_base;
	ncp_init_header(server, req, h);
	signlen = sign_packet(server, req->tx_iov[1].iov_base + sizeof(struct ncp_request_header) - 1, 
			req->tx_iov[1].iov_len - sizeof(struct ncp_request_header) + 1,
			cpu_to_le32(req->tx_totallen), req->sign);
	if (signlen) {
		req->tx_ciov[1].iov_base = req->sign;
		req->tx_ciov[1].iov_len = signlen;
		req->tx_iovlen += 1;
		req->tx_totallen += signlen;
	}
	server->rcv.creq = req;
	server->timeout_last = server->m.time_out;
	server->timeout_retries = server->m.retry_count;
	ncpdgram_send(server->ncp_sock, req);
	mod_timer(&server->timeout_tm, jiffies + server->m.time_out);
}

#define NCP_TCP_XMIT_MAGIC	(0x446D6454)
#define NCP_TCP_XMIT_VERSION	(1)
#define NCP_TCP_RCVD_MAGIC	(0x744E6350)

static void ncptcp_start_request(struct ncp_server *server, struct ncp_request_reply *req)
{
	size_t signlen;
	struct ncp_request_header* h;

	req->tx_ciov = req->tx_iov;
	h = req->tx_iov[1].iov_base;
	ncp_init_header(server, req, h);
	signlen = sign_packet(server, req->tx_iov[1].iov_base + sizeof(struct ncp_request_header) - 1,
			req->tx_iov[1].iov_len - sizeof(struct ncp_request_header) + 1,
			cpu_to_be32(req->tx_totallen + 24), req->sign + 4) + 16;

	req->sign[0] = htonl(NCP_TCP_XMIT_MAGIC);
	req->sign[1] = htonl(req->tx_totallen + signlen);
	req->sign[2] = htonl(NCP_TCP_XMIT_VERSION);
	req->sign[3] = htonl(req->datalen + 8);
	req->tx_iov[0].iov_base = req->sign;
	req->tx_iov[0].iov_len = signlen;
	req->tx_iovlen += 1;
	req->tx_totallen += signlen;

	server->tx.creq = req;
	__ncptcp_try_send(server);
}

static inline void __ncp_start_request(struct ncp_server *server, struct ncp_request_reply *req)
{
	/* we copy the data so that we do not depend on the caller
	   staying alive */
	memcpy(server->txbuf, req->tx_iov[1].iov_base, req->tx_iov[1].iov_len);
	req->tx_iov[1].iov_base = server->txbuf;

	if (server->ncp_sock->type == SOCK_STREAM)
		ncptcp_start_request(server, req);
	else
		ncpdgram_start_request(server, req);
}

static int ncp_add_request(struct ncp_server *server, struct ncp_request_reply *req)
{
	mutex_lock(&server->rcv.creq_mutex);
	if (!ncp_conn_valid(server)) {
		mutex_unlock(&server->rcv.creq_mutex);
		printk(KERN_ERR "ncpfs: tcp: Server died\n");
		return -EIO;
	}
	ncp_req_get(req);
	if (server->tx.creq || server->rcv.creq) {
		req->status = RQ_QUEUED;
		list_add_tail(&req->req, &server->tx.requests);
		mutex_unlock(&server->rcv.creq_mutex);
		return 0;
	}
	__ncp_start_request(server, req);
	mutex_unlock(&server->rcv.creq_mutex);
	return 0;
}

static void __ncp_next_request(struct ncp_server *server)
{
	struct ncp_request_reply *req;

	server->rcv.creq = NULL;
	if (list_empty(&server->tx.requests)) {
		return;
	}
	req = list_entry(server->tx.requests.next, struct ncp_request_reply, req);
	list_del_init(&req->req);
	__ncp_start_request(server, req);
}

static void info_server(struct ncp_server *server, unsigned int id, const void * data, size_t len)
{
	if (server->info_sock) {
		struct kvec iov[2];
		__be32 hdr[2];
	
		hdr[0] = cpu_to_be32(len + 8);
		hdr[1] = cpu_to_be32(id);
	
		iov[0].iov_base = hdr;
		iov[0].iov_len = 8;
		iov[1].iov_base = (void *) data;
		iov[1].iov_len = len;

		do_send(server->info_sock, iov, 2, len + 8, MSG_NOSIGNAL);
	}
}

void ncpdgram_rcv_proc(struct work_struct *work)
{
	struct ncp_server *server =
		container_of(work, struct ncp_server, rcv.tq);
	struct socket* sock;
	
	sock = server->ncp_sock;
	
	while (1) {
		struct ncp_reply_header reply;
		int result;

		result = _recv(sock, &reply, sizeof(reply), MSG_PEEK | MSG_DONTWAIT);
		if (result < 0) {
			break;
		}
		if (result >= sizeof(reply)) {
			struct ncp_request_reply *req;
	
			if (reply.type == NCP_WATCHDOG) {
				unsigned char buf[10];

				if (server->connection != get_conn_number(&reply)) {
					goto drop;
				}
				result = _recv(sock, buf, sizeof(buf), MSG_DONTWAIT);
				if (result < 0) {
					DPRINTK("recv failed with %d\n", result);
					continue;
				}
				if (result < 10) {
					DPRINTK("too short (%u) watchdog packet\n", result);
					continue;
				}
				if (buf[9] != '?') {
					DPRINTK("bad signature (%02X) in watchdog packet\n", buf[9]);
					continue;
				}
				buf[9] = 'Y';
				_send(sock, buf, sizeof(buf));
				continue;
			}
			if (reply.type != NCP_POSITIVE_ACK && reply.type != NCP_REPLY) {
				result = _recv(sock, server->unexpected_packet.data, sizeof(server->unexpected_packet.data), MSG_DONTWAIT);
				if (result < 0) {
					continue;
				}
				info_server(server, 0, server->unexpected_packet.data, result);
				continue;
			}
			mutex_lock(&server->rcv.creq_mutex);
			req = server->rcv.creq;
			if (req && (req->tx_type == NCP_ALLOC_SLOT_REQUEST || (server->sequence == reply.sequence && 
					server->connection == get_conn_number(&reply)))) {
				if (reply.type == NCP_POSITIVE_ACK) {
					server->timeout_retries = server->m.retry_count;
					server->timeout_last = NCP_MAX_RPC_TIMEOUT;
					mod_timer(&server->timeout_tm, jiffies + NCP_MAX_RPC_TIMEOUT);
				} else if (reply.type == NCP_REPLY) {
					result = _recv(sock, server->rxbuf, req->datalen, MSG_DONTWAIT);
#ifdef CONFIG_NCPFS_PACKET_SIGNING
					if (result >= 0 && server->sign_active && req->tx_type != NCP_DEALLOC_SLOT_REQUEST) {
						if (result < 8 + 8) {
							result = -EIO;
						} else {
							unsigned int hdrl;
							
							result -= 8;
							hdrl = sock->sk->sk_family == AF_INET ? 8 : 6;
							if (sign_verify_reply(server, server->rxbuf + hdrl, result - hdrl, cpu_to_le32(result), server->rxbuf + result)) {
								printk(KERN_INFO "ncpfs: Signature violation\n");
								result = -EIO;
							}
						}
					}
#endif
					del_timer(&server->timeout_tm);
				     	server->rcv.creq = NULL;
					ncp_finish_request(server, req, result);
					__ncp_next_request(server);
					mutex_unlock(&server->rcv.creq_mutex);
					continue;
				}
			}
			mutex_unlock(&server->rcv.creq_mutex);
		}
drop:;		
		_recv(sock, &reply, sizeof(reply), MSG_DONTWAIT);
	}
}

static void __ncpdgram_timeout_proc(struct ncp_server *server)
{
	/* If timer is pending, we are processing another request... */
	if (!timer_pending(&server->timeout_tm)) {
		struct ncp_request_reply* req;
		
		req = server->rcv.creq;
		if (req) {
			int timeout;
			
			if (server->m.flags & NCP_MOUNT_SOFT) {
				if (server->timeout_retries-- == 0) {
					__ncp_abort_request(server, req, -ETIMEDOUT);
					return;
				}
			}
			/* Ignore errors */
			ncpdgram_send(server->ncp_sock, req);
			timeout = server->timeout_last << 1;
			if (timeout > NCP_MAX_RPC_TIMEOUT) {
				timeout = NCP_MAX_RPC_TIMEOUT;
			}
			server->timeout_last = timeout;
			mod_timer(&server->timeout_tm, jiffies + timeout);
		}
	}
}

void ncpdgram_timeout_proc(struct work_struct *work)
{
	struct ncp_server *server =
		container_of(work, struct ncp_server, timeout_tq);
	mutex_lock(&server->rcv.creq_mutex);
	__ncpdgram_timeout_proc(server);
	mutex_unlock(&server->rcv.creq_mutex);
}

static int do_tcp_rcv(struct ncp_server *server, void *buffer, size_t len)
{
	int result;
	
	if (buffer) {
		result = _recv(server->ncp_sock, buffer, len, MSG_DONTWAIT);
	} else {
		static unsigned char dummy[1024];
			
		if (len > sizeof(dummy)) {
			len = sizeof(dummy);
		}
		result = _recv(server->ncp_sock, dummy, len, MSG_DONTWAIT);
	}
	if (result < 0) {
		return result;
	}
	if (result > len) {
		printk(KERN_ERR "ncpfs: tcp: bug in recvmsg (%u > %Zu)\n", result, len);
		return -EIO;			
	}
	return result;
}	

static int __ncptcp_rcv_proc(struct ncp_server *server)
{
	/* We have to check the result, so store the complete header */
	while (1) {
		int result;
		struct ncp_request_reply *req;
		int datalen;
		int type;

		while (server->rcv.len) {
			result = do_tcp_rcv(server, server->rcv.ptr, server->rcv.len);
			if (result == -EAGAIN) {
				return 0;
			}
			if (result <= 0) {
				req = server->rcv.creq;
				if (req) {
					__ncp_abort_request(server, req, -EIO);
				} else {
					__ncptcp_abort(server);
				}
				if (result < 0) {
					printk(KERN_ERR "ncpfs: tcp: error in recvmsg: %d\n", result);
				} else {
					DPRINTK(KERN_ERR "ncpfs: tcp: EOF\n");
				}
				return -EIO;
			}
			if (server->rcv.ptr) {
				server->rcv.ptr += result;
			}
			server->rcv.len -= result;
		}
		switch (server->rcv.state) {
			case 0:
				if (server->rcv.buf.magic != htonl(NCP_TCP_RCVD_MAGIC)) {
					printk(KERN_ERR "ncpfs: tcp: Unexpected reply type %08X\n", ntohl(server->rcv.buf.magic));
					__ncptcp_abort(server);
					return -EIO;
				}
				datalen = ntohl(server->rcv.buf.len) & 0x0FFFFFFF;
				if (datalen < 10) {
					printk(KERN_ERR "ncpfs: tcp: Unexpected reply len %d\n", datalen);
					__ncptcp_abort(server);
					return -EIO;
				}
#ifdef CONFIG_NCPFS_PACKET_SIGNING				
				if (server->sign_active) {
					if (datalen < 18) {
						printk(KERN_ERR "ncpfs: tcp: Unexpected reply len %d\n", datalen);
						__ncptcp_abort(server);
						return -EIO;
					}
					server->rcv.buf.len = datalen - 8;
					server->rcv.ptr = (unsigned char*)&server->rcv.buf.p1;
					server->rcv.len = 8;
					server->rcv.state = 4;
					break;
				}
#endif				
				type = ntohs(server->rcv.buf.type);
#ifdef CONFIG_NCPFS_PACKET_SIGNING				
cont:;				
#endif
				if (type != NCP_REPLY) {
					if (datalen - 8 <= sizeof(server->unexpected_packet.data)) {
						*(__u16*)(server->unexpected_packet.data) = htons(type);
						server->unexpected_packet.len = datalen - 8;

						server->rcv.state = 5;
						server->rcv.ptr = server->unexpected_packet.data + 2;
						server->rcv.len = datalen - 10;
						break;
					}					
					DPRINTK("ncpfs: tcp: Unexpected NCP type %02X\n", type);
skipdata2:;
					server->rcv.state = 2;
skipdata:;
					server->rcv.ptr = NULL;
					server->rcv.len = datalen - 10;
					break;
				}
				req = server->rcv.creq;
				if (!req) {
					DPRINTK(KERN_ERR "ncpfs: Reply without appropriate request\n");
					goto skipdata2;
				}
				if (datalen > req->datalen + 8) {
					printk(KERN_ERR "ncpfs: tcp: Unexpected reply len %d (expected at most %Zd)\n", datalen, req->datalen + 8);
					server->rcv.state = 3;
					goto skipdata;
				}
				req->datalen = datalen - 8;
				((struct ncp_reply_header*)server->rxbuf)->type = NCP_REPLY;
				server->rcv.ptr = server->rxbuf + 2;
				server->rcv.len = datalen - 10;
				server->rcv.state = 1;
				break;
#ifdef CONFIG_NCPFS_PACKET_SIGNING				
			case 4:
				datalen = server->rcv.buf.len;
				type = ntohs(server->rcv.buf.type2);
				goto cont;
#endif
			case 1:
				req = server->rcv.creq;
				if (req->tx_type != NCP_ALLOC_SLOT_REQUEST) {
					if (((struct ncp_reply_header*)server->rxbuf)->sequence != server->sequence) {
						printk(KERN_ERR "ncpfs: tcp: Bad sequence number\n");
						__ncp_abort_request(server, req, -EIO);
						return -EIO;
					}
					if ((((struct ncp_reply_header*)server->rxbuf)->conn_low | (((struct ncp_reply_header*)server->rxbuf)->conn_high << 8)) != server->connection) {
						printk(KERN_ERR "ncpfs: tcp: Connection number mismatch\n");
						__ncp_abort_request(server, req, -EIO);
						return -EIO;
					}
				}
#ifdef CONFIG_NCPFS_PACKET_SIGNING				
				if (server->sign_active && req->tx_type != NCP_DEALLOC_SLOT_REQUEST) {
					if (sign_verify_reply(server, server->rxbuf + 6, req->datalen - 6, cpu_to_be32(req->datalen + 16), &server->rcv.buf.type)) {
						printk(KERN_ERR "ncpfs: tcp: Signature violation\n");
						__ncp_abort_request(server, req, -EIO);
						return -EIO;
					}
				}
#endif				
				ncp_finish_request(server, req, req->datalen);
			nextreq:;
				__ncp_next_request(server);
			case 2:
			next:;
				server->rcv.ptr = (unsigned char*)&server->rcv.buf;
				server->rcv.len = 10;
				server->rcv.state = 0;
				break;
			case 3:
				ncp_finish_request(server, server->rcv.creq, -EIO);
				goto nextreq;
			case 5:
				info_server(server, 0, server->unexpected_packet.data, server->unexpected_packet.len);
				goto next;
		}
	}
}

void ncp_tcp_rcv_proc(struct work_struct *work)
{
	struct ncp_server *server =
		container_of(work, struct ncp_server, rcv.tq);

	mutex_lock(&server->rcv.creq_mutex);
	__ncptcp_rcv_proc(server);
	mutex_unlock(&server->rcv.creq_mutex);
}

void ncp_tcp_tx_proc(struct work_struct *work)
{
	struct ncp_server *server =
		container_of(work, struct ncp_server, tx.tq);
	
	mutex_lock(&server->rcv.creq_mutex);
	__ncptcp_try_send(server);
	mutex_unlock(&server->rcv.creq_mutex);
}

static int do_ncp_rpc_call(struct ncp_server *server, int size,
		unsigned char* reply_buf, int max_reply_size)
{
	int result;
	struct ncp_request_reply *req;

	req = ncp_alloc_req();
	if (!req)
		return -ENOMEM;

	req->reply_buf = reply_buf;
	req->datalen = max_reply_size;
	req->tx_iov[1].iov_base = server->packet;
	req->tx_iov[1].iov_len = size;
	req->tx_iovlen = 1;
	req->tx_totallen = size;
	req->tx_type = *(u_int16_t*)server->packet;

	result = ncp_add_request(server, req);
	if (result < 0)
		goto out;

	if (wait_event_interruptible(req->wq, req->status == RQ_DONE)) {
		ncp_abort_request(server, req, -EINTR);
		result = -EINTR;
		goto out;
	}

	result = req->result;

out:
	ncp_req_put(req);

	return result;
}

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

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

	if (server->lock == 0) {
		printk(KERN_ERR "ncpfs: Server not locked!\n");
		return -EIO;
	}
	if (!ncp_conn_valid(server)) {
		return -EIO;
	}
	{
		sigset_t old_set;
		unsigned long mask, flags;

		spin_lock_irqsave(&current->sighand->siglock, flags);
		old_set = current->blocked;
		if (current->flags & PF_EXITING)
			mask = 0;
		else
			mask = sigmask(SIGKILL);
		if (server->m.flags & NCP_MOUNT_INTR) {