/*
 *  SMB2 version specific operations
 *
 *  Copyright (c) 2012, Jeff Layton <jlayton@redhat.com>
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2 as published
 *  by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *  the GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/pagemap.h>
#include "cifsglob.h"
#include "smb2pdu.h"
#include "smb2proto.h"
#include "cifsproto.h"
#include "cifs_debug.h"

static int
change_conf(struct TCP_Server_Info *server)
{
	server->credits += server->echo_credits + server->oplock_credits;
	server->oplock_credits = server->echo_credits = 0;
	switch (server->credits) {
	case 0:
		return -1;
	case 1:
		server->echoes = false;
		server->oplocks = false;
		cERROR(1, "disabling echoes and oplocks");
		break;
	case 2:
		server->echoes = true;
		server->oplocks = false;
		server->echo_credits = 1;
		cFYI(1, "disabling oplocks");
		break;
	default:
		server->echoes = true;
		server->oplocks = true;
		server->echo_credits = 1;
		server->oplock_credits = 1;
	}
	server->credits -= server->echo_credits + server->oplock_credits;
	return 0;
}

static void
smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add,
		 const int optype)
{
	int *val, rc = 0;
	spin_lock(&server->req_lock);
	val = server->ops->get_credits_field(server, optype);
	*val += add;
	server->in_flight--;
	if (server->in_flight == 0 && (optype & CIFS_OP_MASK) != CIFS_NEG_OP)
		rc = change_conf(server);
	spin_unlock(&server->req_lock);
	wake_up(&server->request_q);
	if (rc)
		cifs_reconnect(server);
}

static void
smb2_set_credits(struct TCP_Server_Info *server, const int val)
{
	spin_lock(&server->req_lock);
	server->credits = val;
	spin_unlock(&server->req_lock);
}

static int *
smb2_get_credits_field(struct TCP_Server_Info *server, const int optype)
{
	switch (optype) {
	case CIFS_ECHO_OP:
		return &server->echo_credits;
	case CIFS_OBREAK_OP:
		return &server->oplock_credits;
	default:
		return &server->credits;
	}
}

static unsigned int
smb2_get_credits(struct mid_q_entry *mid)
{
	return le16_to_cpu(((struct smb2_hdr *)mid->resp_buf)->CreditRequest);
}

static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
	__u64 mid;
	/* for SMB2 we need the current value */
	spin_lock(&GlobalMid_Lock);
	mid = server->CurrentMid++;
	spin_unlock(&GlobalMid_Lock);
	return mid;
}

static struct mid_q_entry *
smb2_find_mid(struct TCP_Server_Info *server, char *buf)
{
	struct mid_q_entry *mid;
	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;

	spin_lock(&GlobalMid_Lock);
	list_for_each_entry(mid, &server->pending_mid_q, qhead) {
		if ((mid->mid == hdr->MessageId) &&
		    (mid->mid_state == MID_REQUEST_SUBMITTED) &&
		    (mid->command == hdr->Command)) {
			spin_unlock(&GlobalMid_Lock);
			return mid;
		}
	}
	spin_unlock(&GlobalMid_Lock);
	return NULL;
}

static void
smb2_dump_detail(void *buf)
{
#ifdef CONFIG_CIFS_DEBUG2
	struct smb2_hdr *smb = (struct smb2_hdr *)buf;

	cERROR(1, "Cmd: %d Err: 0x%x Flags: 0x%x Mid: %llu Pid: %d",
		  smb->Command, smb->Status, smb->Flags, smb->MessageId,
		  smb->ProcessId);
	cERROR(1, "smb buf %p len %u", smb, smb2_calc_size(smb));
#endif
}

static bool
smb2_need_neg(struct TCP_Server_Info *server)
{
	return server->max_read == 0;
}

static int
smb2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
	int rc;
	ses->server->CurrentMid = 0;
	rc = SMB2_negotiate(xid, ses);
	/* BB we probably don't need to retry with modern servers */
	if (rc == -EAGAIN)
		rc = -EHOSTDOWN;
	return rc;
}

static unsigned int
smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
	struct TCP_Server_Info *server = tcon->ses->server;
	unsigned int wsize;

	/* start with specified wsize, or default */
	wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
	wsize = min_t(unsigned int, wsize, server->max_write);
	/*
	 * limit write size to 2 ** 16, because we don't support multicredit
	 * requests now.
	 */
	wsize = min_t(unsigned int, wsize, 2 << 15);

	/* limit to the amount that we can kmap at once */
	wsize = min_t(unsigned int, wsize, CIFS_KMAP_SIZE_LIMIT);

	return wsize;
}

static unsigned int
smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
	struct TCP_Server_Info *server = tcon->ses->server;
	unsigned int rsize;

	/* start with specified rsize, or default */
	rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
	rsize = min_t(unsigned int, rsize, server->max_read);
	/*
	 * limit write size to 2 ** 16, because we don't support multicredit
	 * requests now.
	 */
	rsize = min_t(unsigned int, rsize, 2 << 15);

	/* limit to the amount that we can kmap at once */
	rsize = min_t(unsigned int, rsize, CIFS_KMAP_SIZE_LIMIT);

	return rsize;
}

static int
smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
			struct cifs_sb_info *cifs_sb, const char *full_path)
{
	int rc;
	__u64 persistent_fid, volatile_fid;
	__le16 *utf16_path;

	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
	if (!utf16_path)
		return -ENOMEM;

	rc = SMB2_open(xid, tcon, utf16_path, &persistent_fid, &volatile_fid,
		       FILE_READ_ATTRIBUTES, FILE_OPEN, 0, 0, NULL);
	if (rc) {
		kfree(utf16_path);
		return rc;
	}

	rc = SMB2_close(xid, tcon, persistent_fid, volatile_fid);
	kfree(utf16_path);
	return rc;
}

static int
smb2_get_srv_inum(const unsigned int xid, struct cifs_tcon *tcon,
		  struct cifs_sb_info *cifs_sb, const char *full_path,
		  u64 *uniqueid, FILE_ALL_INFO *data)
{
	*uniqueid = le64_to_cpu(data->IndexNumber);
	return 0;
}

static int
smb2_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
		     struct cifs_fid *fid, FILE_ALL_INFO *data)
{
	int rc;
	struct smb2_file_all_info *smb2_data;

	smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + MAX_NAME * 2,
			    GFP_KERNEL);
	if (smb2_data == NULL)
		return -ENOMEM;

	rc = SMB2_query_info(xid, tcon, fid->persistent_fid, fid->volatile_fid,
			     smb2_data);
	if (!rc)
		move_smb2_info_to_cifs(data, smb2_data);
	kfree(smb2_data);
	return rc;
}

static char *
smb2_build_path_to_root(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
			struct cifs_tcon *tcon)
{
	int pplen = vol->prepath ? strlen(vol->prepath) : 0;
	char *full_path = NULL;

	/* if no prefix path, simply set path to the root of share to "" */
	if (pplen == 0) {
		full_path = kzalloc(2, GFP_KERNEL);
		return full_path;
	}

	cERROR(1, "prefixpath is not supported for SMB2 now");
	return NULL;
}

static bool
smb2_can_echo(struct TCP_Server_Info *server)
{
	return server->echoes;
}

static void
smb2_clear_stats(struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
	int i;
	for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++) {
		atomic_set(&tcon->stats.smb2_stats.smb2_com_sent[i], 0);
		atomic_set(&tcon->stats.smb2_stats.smb2_com_failed[i], 0);
	}
#endif
}

static void
smb2_print_stats(struct seq_file *m, struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
	atomic_t *sent = tcon->stats.smb2_stats.smb2_com_sent;
	atomic_t *failed = tcon->stats.smb2_stats.smb2_com_failed;
	seq_printf(m, "\nNegotiates: %d sent %d failed",
		   atomic_read(&sent[SMB2_NEGOTIATE_HE]),
		   atomic_read(&failed[SMB2_NEGOTIATE_HE]));
	seq_printf(m, "\nSessionSetups: %d sent %d failed",
		   atomic_read(&sent[SMB2_SESSION_SETUP_HE]),
		   atomic_read(&failed[SMB2_SESSION_SETUP_HE]));
#define SMB2LOGOFF		0x0002 /* trivial request/resp */
	seq_printf(m, "\nLogoffs: %d sent %d failed",
		   atomic_read(&sent[SMB2_LOGOFF_HE]),
		   atomic_read(&failed[SMB2_LOGOFF_HE]));
	seq_printf(m, "\nTreeConnects: %d sent %d failed",
		   atomic_read(&sent[SMB2_TREE_CONNECT_HE]),
		   atomic_read(&failed[SMB2_TREE_CONNECT_HE]));
	seq_printf(m, "\nTreeDisconnects: %d sent %d failed",
		   atomic_read(&sent[SMB2_TREE_DISCONNECT_HE]),
		   atomic_read(&failed[SMB2_TREE_DISCONNECT_HE]));
	seq_printf(m, "\nCreates: %d sent %d failed",
		   atomic_read(&sent[SMB2_CREATE_HE]),
		   atomic_read(&failed[SMB2_CREATE_HE]));
	seq_printf(m, "\nCloses: %d sent %d failed",
		   atomic_read(&sent[SMB2_CLOSE_HE]),
		   atomic_read(&failed[SMB2_CLOSE_HE]));
	seq_printf(m, "\nFlushes: %d sent %d failed",
		   atomic_read(&sent[SMB2_FLUSH_HE]),
		   atomic_read(&failed[SMB2_FLUSH_HE]));
	seq_printf(m, "\nReads: %d sent %d failed",
		   atomic_read(&sent[SMB2_READ_HE]),
		   atomic_read(&failed[SMB2_READ_HE]));
	seq_printf(m, "\nWrites: %d sent %d failed",
		   atomic_read(&sent[SMB2_WRITE_HE]),
		   atomic_read(&failed[SMB2_WRITE_HE]));
	seq_printf(m, "\nLocks: %d sent %d failed",
		   atomic_read(&sent[SMB2_LOCK_HE]),
		   atomic_read(&failed[SMB2_LOCK_HE]));
	seq_printf(m, "\nIOCTLs: %d sent %d failed",
		   atomic_read(&sent[SMB2_IOCTL_HE]),
		   atomic_read(&failed[SMB2_IOCTL_HE]));
	seq_printf(m, "\nCancels: %d sent %d failed",
		   atomic_read(&sent[SMB2_CANCEL_HE]),
		   atomic_read(&failed[SMB2_CANCEL_HE]));
	seq_printf(m, "\nEchos: %d sent %d failed",
		   atomic_read(&sent[SMB2_ECHO_HE]),
		   atomic_read(&failed[SMB2_ECHO_HE]));
	seq_printf(m, "\nQueryDirectories: %d sent %d failed",
		   atomic_read(&sent[SMB2_QUERY_DIRECTORY_HE]),
		   atomic_read(&failed[SMB2_QUERY_DIRECTORY_HE]));
	seq_printf(m, "\nChangeNotifies: %d sent %d failed",
		   atomic_read(&sent[SMB2_CHANGE_NOTIFY_HE]),
		   atomic_read(&failed[SMB2_CHANGE_NOTIFY_HE]));
	seq_printf(m, "\nQueryInfos: %d sent %d failed",
		   atomic_read(&sent[SMB2_QUERY_INFO_HE]),
		   atomic_read(&failed[SMB2_QUERY_INFO_HE]));
	seq_printf(m, "\nSetInfos: %d sent %d failed",
		   atomic_read(&sent[SMB2_SET_INFO_HE]),
		   atomic_read(&failed[SMB2_SET_INFO_HE]));
	seq_printf(m, "\nOplockBreaks: %d sent %d failed",
		   atomic_read(&sent[SMB2_OPLOCK_BREAK_HE]),
		   atomic_read(&failed[SMB2_OPLOCK_BREAK_HE]));
#endif
}

static void
smb2_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
{
	/* struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode); */
	cfile->fid.persistent_fid = fid->persistent_fid;
	cfile->fid.volatile_fid = fid->volatile_fid;
	/* cifs_set_oplock_level(cinode, oplock); */
	/* cinode->can_cache_brlcks = cinode->clientCanCacheAll; */
}

static int
smb2_close_file(const unsigned int xid, struct cifs_tcon *tcon,
		struct cifs_fid *fid)
{
	return SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static int
smb2_flush_file(const unsigned int xid, struct cifs_tcon *tcon,
		struct cifs_fid *fid)
{
	return SMB2_flush(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static unsigned int
smb2_read_data_offset(char *buf)
{
	struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
	return rsp->DataOffset;
}

static unsigned int
smb2_read_data_length(char *buf)
{
	struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
	return le32_to_cpu(rsp->DataLength);
}


static int
smb2_sync_read(const unsigned int xid, struct cifsFileInfo *cfile,
	       struct cifs_io_parms *parms, unsigned int *bytes_read,
	       char **buf, int *buf_type)
{
	parms->persistent_fid = cfile->fid.persistent_fid;
	parms->volatile_fid = cfile->fid.volatile_fid;
	return SMB2_read(xid, parms, bytes_read, buf, buf_type);
}

struct smb_version_operations smb21_operations = {
	.setup_request = smb2_setup_request,
	.setup_async_request = smb2_setup_async_request,
	.check_receive = smb2_check_receive,
	.add_credits = smb2_add_credits,
	.set_credits = smb2_set_credits,
	.get_credits_field = smb2_get_credits_field,
	.get_credits = smb2_get_credits,
	.get_next_mid = smb2_get_next_mid,
	.read_data_offset = smb2_read_data_offset,
	.read_data_length = smb2_read_data_length,
	.map_error = map_smb2_to_linux_error,
	.find_mid = smb2_find_mid,
	.check_message = smb2_check_message,
	.dump_detail = smb2_dump_detail,
	.clear_stats = smb2_clear_stats,
	.print_stats = smb2_print_stats,
	.need_neg = smb2_need_neg,
	.negotiate = smb2_negotiate,
	.negotiate_wsize = smb2_negotiate_wsize,
	.negotiate_rsize = smb2_negotiate_rsize,
	.sess_setup = SMB2_sess_setup,
	.logoff = SMB2_logoff,
	.tree_connect = SMB2_tcon,
	.tree_disconnect = SMB2_tdis,
	.is_path_accessible = smb2_is_path_accessible,
	.can_echo = smb2_can_echo,
	.echo = SMB2_echo,
	.query_path_info = smb2_query_path_info,
	.get_srv_inum = smb2_get_srv_inum,
	.query_file_info = smb2_query_file_info,
	.build_path_to_root = smb2_build_path_to_root,
	.mkdir = smb2_mkdir,
	.mkdir_setinfo = smb2_mkdir_setinfo,
	.rmdir = smb2_rmdir,
	.unlink = smb2_unlink,
	.open = smb2_open_file,
	.set_fid = smb2_set_fid,
	.close = smb2_close_file,
	.flush = smb2_flush_file,
	.async_readv = smb2_async_readv,
	.async_writev = smb2_async_writev,
	.sync_read = smb2_sync_read,
};

struct smb_version_values smb21_values = {
	.version_string = SMB21_VERSION_STRING,
	.header_size = sizeof(struct smb2_hdr),
	.max_header_size = MAX_SMB2_HDR_SIZE,
	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
	.lock_cmd = SMB2_LOCK,
	.cap_unix = 0,
	.cap_nt_find = SMB2_NT_FIND,
	.cap_large_files = SMB2_LARGE_FILES,
};