/*
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */
#include <linux/module.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs_mount.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/bc_xprt.h>
#include "internal.h"
#include "callback.h"
#include "delegation.h"
#include "pnfs.h"
#include "netns.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

/*
 * Turn off NFSv4 uid/gid mapping when using AUTH_SYS
 */
static bool nfs4_disable_idmapping = true;

/*
 * Get a unique NFSv4.0 callback identifier which will be used
 * by the V4.0 callback service to lookup the nfs_client struct
 */
static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
{
	int ret = 0;
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->rpc_ops->version != 4 || minorversion != 0)
		return ret;
retry:
	if (!idr_pre_get(&nn->cb_ident_idr, GFP_KERNEL))
		return -ENOMEM;
	spin_lock(&nn->nfs_client_lock);
	ret = idr_get_new(&nn->cb_ident_idr, clp, &clp->cl_cb_ident);
	spin_unlock(&nn->nfs_client_lock);
	if (ret == -EAGAIN)
		goto retry;
	return ret;
}

#ifdef CONFIG_NFS_V4_1
static void nfs4_shutdown_session(struct nfs_client *clp)
{
	if (nfs4_has_session(clp)) {
		nfs4_destroy_session(clp->cl_session);
		nfs4_destroy_clientid(clp);
	}

}
#else /* CONFIG_NFS_V4_1 */
static void nfs4_shutdown_session(struct nfs_client *clp)
{
}
#endif /* CONFIG_NFS_V4_1 */

struct nfs_client *nfs4_alloc_client(const struct nfs_client_initdata *cl_init)
{
	int err;
	struct nfs_client *clp = nfs_alloc_client(cl_init);
	if (IS_ERR(clp))
		return clp;

	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
	if (err)
		goto error;

	spin_lock_init(&clp->cl_lock);
	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
	clp->cl_minorversion = cl_init->minorversion;
	clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
	return clp;

error:
	kfree(clp);
	return ERR_PTR(err);
}

/*
 * Destroy the NFS4 callback service
 */
static void nfs4_destroy_callback(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down(clp->cl_mvops->minor_version);
}

static void nfs4_shutdown_client(struct nfs_client *clp)
{
	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
		nfs4_kill_renewd(clp);
	nfs4_shutdown_session(clp);
	nfs4_destroy_callback(clp);
	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
		nfs_idmap_delete(clp);

	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
	kfree(clp->cl_serverowner);
	kfree(clp->cl_serverscope);
	kfree(clp->cl_implid);
}

void nfs4_free_client(struct nfs_client *clp)
{
	nfs4_shutdown_client(clp);
	nfs_free_client(clp);
}

/*
 * Initialize the NFS4 callback service
 */
static int nfs4_init_callback(struct nfs_client *clp)
{
	int error;

	if (clp->rpc_ops->version == 4) {
		struct rpc_xprt *xprt;

		xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);

		if (nfs4_has_session(clp)) {
			error = xprt_setup_backchannel(xprt,
						NFS41_BC_MIN_CALLBACKS);
			if (error < 0)
				return error;
		}

		error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
		if (error < 0) {
			dprintk("%s: failed to start callback. Error = %d\n",
				__func__, error);
			return error;
		}
		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
	}
	return 0;
}

/*
 * Initialize the minor version specific parts of an NFS4 client record
 */
static int nfs4_init_client_minor_version(struct nfs_client *clp)
{
#if defined(CONFIG_NFS_V4_1)
	if (clp->cl_mvops->minor_version) {
		struct nfs4_session *session = NULL;
		/*
		 * Create the session and mark it expired.
		 * When a SEQUENCE operation encounters the expired session
		 * it will do session recovery to initialize it.
		 */
		session = nfs4_alloc_session(clp);
		if (!session)
			return -ENOMEM;

		clp->cl_session = session;
		/*
		 * The create session reply races with the server back
		 * channel probe. Mark the client NFS_CS_SESSION_INITING
		 * so that the client back channel can find the
		 * nfs_client struct
		 */
		nfs_mark_client_ready(clp, NFS_CS_SESSION_INITING);
	}
#endif /* CONFIG_NFS_V4_1 */

	return nfs4_init_callback(clp);
}

/**
 * nfs4_init_client - Initialise an NFS4 client record
 *
 * @clp: nfs_client to initialise
 * @timeparms: timeout parameters for underlying RPC transport
 * @ip_addr: callback IP address in presentation format
 * @authflavor: authentication flavor for underlying RPC transport
 *
 * Returns pointer to an NFS client, or an ERR_PTR value.
 */
struct nfs_client *nfs4_init_client(struct nfs_client *clp,
				    const struct rpc_timeout *timeparms,
				    const char *ip_addr,
				    rpc_authflavor_t authflavour)
{
	char buf[INET6_ADDRSTRLEN + 1];
	int error;

	if (clp->cl_cons_state == NFS_CS_READY) {
		/* the client is initialised already */
		dprintk("<-- nfs4_init_client() = 0 [already %p]\n", clp);
		return clp;
	}

	/* Check NFS protocol revision and initialize RPC op vector */
	clp->rpc_ops = &nfs_v4_clientops;

	__set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
	error = nfs_create_rpc_client(clp, timeparms, authflavour);
	if (error < 0)
		goto error;

	/* If no clientaddr= option was specified, find a usable cb address */
	if (ip_addr == NULL) {
		struct sockaddr_storage cb_addr;
		struct sockaddr *sap = (struct sockaddr *)&cb_addr;

		error = rpc_localaddr(clp->cl_rpcclient, sap, sizeof(cb_addr));
		if (error < 0)
			goto error;
		error = rpc_ntop(sap, buf, sizeof(buf));
		if (error < 0)
			goto error;
		ip_addr = (const char *)buf;
	}
	strlcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));

	error = nfs_idmap_new(clp);
	if (error < 0) {
		dprintk("%s: failed to create idmapper. Error = %d\n",
			__func__, error);
		goto error;
	}
	__set_bit(NFS_CS_IDMAP, &clp->cl_res_state);

	error = nfs4_init_client_minor_version(clp);
	if (error < 0)
		goto error;

	if (!nfs4_has_session(clp))
		nfs_mark_client_ready(clp, NFS_CS_READY);
	return clp;

error:
	nfs_mark_client_ready(clp, error);
	nfs_put_client(clp);
	dprintk("<-- nfs4_init_client() = xerror %d\n", error);
	return ERR_PTR(error);
}

static void nfs4_destroy_server(struct nfs_server *server)
{
	nfs_server_return_all_delegations(server);
	unset_pnfs_layoutdriver(server);
	nfs4_purge_state_owners(server);
}

/*
 * NFSv4.0 callback thread helper
 *
 * Find a client by callback identifier
 */
struct nfs_client *
nfs4_find_client_ident(struct net *net, int cb_ident)
{
	struct nfs_client *clp;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	spin_lock(&nn->nfs_client_lock);
	clp = idr_find(&nn->cb_ident_idr, cb_ident);
	if (clp)
		atomic_inc(&clp->cl_count);
	spin_unlock(&nn->nfs_client_lock);
	return clp;
}

#if defined(CONFIG_NFS_V4_1)
/* Common match routine for v4.0 and v4.1 callback services */
static bool nfs4_cb_match_client(const struct sockaddr *addr,
		struct nfs_client *clp, u32 minorversion)
{
	struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;

	/* Don't match clients that failed to initialise */
	if (!(clp->cl_cons_state == NFS_CS_READY ||
	    clp->cl_cons_state == NFS_CS_SESSION_INITING))
		return false;

	smp_rmb();

	/* Match the version and minorversion */
	if (clp->rpc_ops->version != 4 ||
	    clp->cl_minorversion != minorversion)
		return false;

	/* Match only the IP address, not the port number */
	if (!nfs_sockaddr_match_ipaddr(addr, clap))
		return false;

	return true;
}

/*
 * NFSv4.1 callback thread helper
 * For CB_COMPOUND calls, find a client by IP address, protocol version,
 * minorversion, and sessionID
 *
 * Returns NULL if no such client
 */
struct nfs_client *
nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
			   struct nfs4_sessionid *sid)
{
	struct nfs_client *clp;
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	spin_lock(&nn->nfs_client_lock);
	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
		if (nfs4_cb_match_client(addr, clp, 1) == false)
			continue;

		if (!nfs4_has_session(clp))
			continue;

		/* Match sessionid*/
		if (memcmp(clp->cl_session->sess_id.data,
		    sid->data, NFS4_MAX_SESSIONID_LEN) != 0)
			continue;

		atomic_inc(&clp->cl_count);
		spin_unlock(&nn->nfs_client_lock);
		return clp;
	}
	spin_unlock(&nn->nfs_client_lock);
	return NULL;
}

#else /* CONFIG_NFS_V4_1 */

struct nfs_client *
nfs4_find_client_sessionid(struct net *net, const struct sockaddr *addr,
			   struct nfs4_sessionid *sid)
{
	return NULL;
}
#endif /* CONFIG_NFS_V4_1 */

/*
 * Set up an NFS4 client
 */
static int nfs4_set_client(struct nfs_server *server,
		const char *hostname,
		const struct sockaddr *addr,
		const size_t addrlen,
		const char *ip_addr,
		rpc_authflavor_t authflavour,
		int proto, const struct rpc_timeout *timeparms,
		u32 minorversion, struct net *net)
{
	struct nfs_client_initdata cl_init = {
		.hostname = hostname,
		.addr = addr,
		.addrlen = addrlen,
		.rpc_ops = &nfs_v4_clientops,
		.proto = proto,
		.minorversion = minorversion,
		.net = net,
	};
	struct nfs_client *clp;
	int error;

	dprintk("--> nfs4_set_client()\n");

	if (server->flags & NFS_MOUNT_NORESVPORT)
		set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);

	/* Allocate or find a client reference we can use */
	clp = nfs_get_client(&cl_init, timeparms, ip_addr, authflavour);
	if (IS_ERR(clp)) {
		error = PTR_ERR(clp);
		goto error;
	}

	/*
	 * Query for the lease time on clientid setup or renewal
	 *
	 * Note that this will be set on nfs_clients that were created
	 * only for the DS role and did not set this bit, but now will
	 * serve a dual role.
	 */
	set_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state);

	server->nfs_client = clp;
	dprintk("<-- nfs4_set_client() = 0 [new %p]\n", clp);
	return 0;
error:
	dprintk("<-- nfs4_set_client() = xerror %d\n", error);
	return error;
}

/*
 * Set up a pNFS Data Server client.
 *
 * Return any existing nfs_client that matches server address,port,version
 * and minorversion.
 *
 * For a new nfs_client, use a soft mount (default), a low retrans and a
 * low timeout interval so that if a connection is lost, we retry through
 * the MDS.
 */
struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,
		const struct sockaddr *ds_addr, int ds_addrlen,
		int ds_proto, unsigned int ds_timeo, unsigned int ds_retrans)
{
	struct nfs_client_initdata cl_init = {
		.addr = ds_addr,
		.addrlen = ds_addrlen,
		.rpc_ops = &nfs_v4_clientops,
		.proto = ds_proto,
		.minorversion = mds_clp->cl_minorversion,
		.net = mds_clp->cl_net,
	};
	struct rpc_timeout ds_timeout;
	struct nfs_client *clp;

	/*
	 * Set an authflavor equual to the MDS value. Use the MDS nfs_client
	 * cl_ipaddr so as to use the same EXCHANGE_ID co_ownerid as the MDS
	 * (section 13.1 RFC 5661).
	 */
	nfs_init_timeout_values(&ds_timeout, ds_proto, ds_timeo, ds_retrans);
	clp = nfs_get_client(&cl_init, &ds_timeout, mds_clp->cl_ipaddr,
			     mds_clp->cl_rpcclient->cl_auth->au_flavor);

	dprintk("<-- %s %p\n", __func__, clp);
	return clp;
}
EXPORT_SYMBOL_GPL(nfs4_set_ds_client);

/*
 * Session has been established, and the client marked ready.
 * Set the mount rsize and wsize with negotiated fore channel
 * attributes which will be bound checked in nfs_server_set_fsinfo.
 */
static void nfs4_session_set_rwsize(struct nfs_server *server)
{
#ifdef CONFIG_NFS_V4_1
	struct nfs4_session *sess;
	u32 server_resp_sz;
	u32 server_rqst_sz;

	if (!nfs4_has_session(server->nfs_client))
		return;
	sess = server->nfs_client->cl_session;
	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;

	if (server->rsize > server_resp_sz)
		server->rsize = server_resp_sz;
	if (server->wsize > server_rqst_sz)
		server->wsize = server_rqst_sz;
#endif /* CONFIG_NFS_V4_1 */
}

static int nfs4_server_common_setup(struct nfs_server *server,
		struct nfs_fh *mntfh)
{
	struct nfs_fattr *fattr;
	int error;

	BUG_ON(!server->nfs_client);
	BUG_ON(!server->nfs_client->rpc_ops);
	BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);

	/* data servers support only a subset of NFSv4.1 */
	if (is_ds_only_client(server->nfs_client))
		return -EPROTONOSUPPORT;

	fattr = nfs_alloc_fattr();
	if (fattr == NULL)
		return -ENOMEM;

	/* We must ensure the session is initialised first */
	error = nfs4_init_session(server);
	if (error < 0)
		goto out;

	/* Probe the root fh to retrieve its FSID and filehandle */
	error = nfs4_get_rootfh(server, mntfh);
	if (error < 0)
		goto out;

	dprintk("Server FSID: %llx:%llx\n",
			(unsigned long long) server->fsid.major,
			(unsigned long long) server->fsid.minor);
	dprintk("Mount FH: %d\n", mntfh->size);

	nfs4_session_set_rwsize(server);

	error = nfs_probe_fsinfo(server, mntfh, fattr);
	if (error < 0)
		goto out;

	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
		server->namelen = NFS4_MAXNAMLEN;

	nfs_server_insert_lists(server);
	server->mount_time = jiffies;
	server->destroy = nfs4_destroy_server;
out:
	nfs_free_fattr(fattr);
	return error;
}

/*
 * Create a version 4 volume record
 */
static int nfs4_init_server(struct nfs_server *server,
		const struct nfs_parsed_mount_data *data)
{
	struct rpc_timeout timeparms;
	int error;

	dprintk("--> nfs4_init_server()\n");

	nfs_init_timeout_values(&timeparms, data->nfs_server.protocol,
			data->timeo, data->retrans);

	/* Initialise the client representation from the mount data */
	server->flags = data->flags;
	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR|NFS_CAP_POSIX_LOCK;
	if (!(data->flags & NFS_MOUNT_NORDIRPLUS))
			server->caps |= NFS_CAP_READDIRPLUS;
	server->options = data->options;

	/* Get a client record */
	error = nfs4_set_client(server,
			data->nfs_server.hostname,
			(const struct sockaddr *)&data->nfs_server.address,
			data->nfs_server.addrlen,
			data->client_address,
			data->auth_flavors[0],
			data->nfs_server.protocol,
			&timeparms,
			data->minorversion,
			data->net);
	if (error < 0)
		goto error;

	/*
	 * Don't use NFS uid/gid mapping if we're using AUTH_SYS or lower
	 * authentication.
	 */
	if (nfs4_disable_idmapping && data->auth_flavors[0] == RPC_AUTH_UNIX)
		server->caps |= NFS_CAP_UIDGID_NOMAP;

	if (data->rsize)
		server->rsize = nfs_block_size(data->rsize, NULL);
	if (data->wsize)
		server->wsize = nfs_block_size(data->wsize, NULL);

	server->acregmin = data->acregmin * HZ;
	server->acregmax = data->acregmax * HZ;
	server->acdirmin = data->acdirmin * HZ;
	server->acdirmax = data->acdirmax * HZ;

	server->port = data->nfs_server.port;

	error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);

error:
	/* Done */
	dprintk("<-- nfs4_init_server() = %d\n", error);
	return error;
}

/*
 * Create a version 4 volume record
 * - keyed on server and FSID
 */
struct nfs_server *nfs4_create_server(const struct nfs_parsed_mount_data *data,
				      struct nfs_fh *mntfh)
{
	struct nfs_server *server;
	int error;

	dprintk("--> nfs4_create_server()\n");

	server = nfs_alloc_server();
	if (!server)
		return ERR_PTR(-ENOMEM);

	/* set up the general RPC client */
	error = nfs4_init_server(server, data);
	if (error < 0)
		goto error;

	error = nfs4_server_common_setup(server, mntfh);
	if (error < 0)
		goto error;

	dprintk("<-- nfs4_create_server() = %p\n", server);
	return server;

error:
	nfs_free_server(server);
	dprintk("<-- nfs4_create_server() = error %d\n", error);
	return ERR_PTR(error);
}

/*
 * Create an NFS4 referral server record
 */
struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
					       struct nfs_fh *mntfh)
{
	struct nfs_client *parent_client;
	struct nfs_server *server, *parent_server;
	int error;

	dprintk("--> nfs4_create_referral_server()\n");

	server = nfs_alloc_server();
	if (!server)
		return ERR_PTR(-ENOMEM);

	parent_server = NFS_SB(data->sb);
	parent_client = parent_server->nfs_client;

	/* Initialise the client representation from the parent server */
	nfs_server_copy_userdata(server, parent_server);
	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR;

	/* Get a client representation.
	 * Note: NFSv4 always uses TCP, */
	error = nfs4_set_client(server, data->hostname,
				data->addr,
				data->addrlen,
				parent_client->cl_ipaddr,
				data->authflavor,
				rpc_protocol(parent_server->client),
				parent_server->client->cl_timeout,
				parent_client->cl_mvops->minor_version,
				parent_client->cl_net);
	if (error < 0)
		goto error;

	error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout, data->authflavor);
	if (error < 0)
		goto error;

	error = nfs4_server_common_setup(server, mntfh);
	if (error < 0)
		goto error;

	dprintk("<-- nfs_create_referral_server() = %p\n", server);
	return server;

error:
	nfs_free_server(server);
	dprintk("<-- nfs4_create_referral_server() = error %d\n", error);
	return ERR_PTR(error);
}

module_param(nfs4_disable_idmapping, bool, 0644);
MODULE_PARM_DESC(nfs4_disable_idmapping,
		"Turn off NFSv4 idmapping when using 'sec=sys'");