/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program 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
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ptlrpc/sec_null.c
 *
 * Author: Eric Mei <ericm@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_SEC

#include <obd_support.h>
#include <obd_cksum.h>
#include <obd_class.h>
#include <lustre_net.h>
#include <lustre_sec.h>

#include "ptlrpc_internal.h"

static struct ptlrpc_sec_policy null_policy;
static struct ptlrpc_sec	null_sec;
static struct ptlrpc_cli_ctx    null_cli_ctx;
static struct ptlrpc_svc_ctx    null_svc_ctx;

/*
 * we can temporarily use the topmost 8-bits of lm_secflvr to identify
 * the source sec part.
 */
static inline
void null_encode_sec_part(struct lustre_msg *msg, enum lustre_sec_part sp)
{
	msg->lm_secflvr |= (((__u32)sp) & 0xFF) << 24;
}

static inline
enum lustre_sec_part null_decode_sec_part(struct lustre_msg *msg)
{
	return (msg->lm_secflvr >> 24) & 0xFF;
}

static int null_ctx_refresh(struct ptlrpc_cli_ctx *ctx)
{
	/* should never reach here */
	LBUG();
	return 0;
}

static
int null_ctx_sign(struct ptlrpc_cli_ctx *ctx, struct ptlrpc_request *req)
{
	req->rq_reqbuf->lm_secflvr = SPTLRPC_FLVR_NULL;

	if (!req->rq_import->imp_dlm_fake) {
		struct obd_device *obd = req->rq_import->imp_obd;

		null_encode_sec_part(req->rq_reqbuf,
				     obd->u.cli.cl_sp_me);
	}
	req->rq_reqdata_len = req->rq_reqlen;
	return 0;
}

static
int null_ctx_verify(struct ptlrpc_cli_ctx *ctx, struct ptlrpc_request *req)
{
	__u32 cksums, cksumc;

	LASSERT(req->rq_repdata);

	req->rq_repmsg = req->rq_repdata;
	req->rq_replen = req->rq_repdata_len;

	if (req->rq_early) {
		cksums = lustre_msg_get_cksum(req->rq_repdata);
		cksumc = lustre_msg_calc_cksum(req->rq_repmsg);
		if (cksumc != cksums) {
			CDEBUG(D_SEC,
			       "early reply checksum mismatch: %08x != %08x\n",
			       cksumc, cksums);
			return -EINVAL;
		}
	}

	return 0;
}

static
struct ptlrpc_sec *null_create_sec(struct obd_import *imp,
				   struct ptlrpc_svc_ctx *svc_ctx,
				   struct sptlrpc_flavor *sf)
{
	LASSERT(SPTLRPC_FLVR_POLICY(sf->sf_rpc) == SPTLRPC_POLICY_NULL);

	/* general layer has take a module reference for us, because we never
	 * really destroy the sec, simply release the reference here.
	 */
	sptlrpc_policy_put(&null_policy);
	return &null_sec;
}

static
void null_destroy_sec(struct ptlrpc_sec *sec)
{
	LASSERT(sec == &null_sec);
}

static
struct ptlrpc_cli_ctx *null_lookup_ctx(struct ptlrpc_sec *sec,
				       struct vfs_cred *vcred,
				       int create, int remove_dead)
{
	atomic_inc(&null_cli_ctx.cc_refcount);
	return &null_cli_ctx;
}

static
int null_flush_ctx_cache(struct ptlrpc_sec *sec,
			 uid_t uid,
			 int grace, int force)
{
	return 0;
}

static
int null_alloc_reqbuf(struct ptlrpc_sec *sec,
		      struct ptlrpc_request *req,
		      int msgsize)
{
	if (!req->rq_reqbuf) {
		int alloc_size = size_roundup_power2(msgsize);

		LASSERT(!req->rq_pool);
		req->rq_reqbuf = libcfs_kvzalloc(alloc_size, GFP_NOFS);
		if (!req->rq_reqbuf)
			return -ENOMEM;

		req->rq_reqbuf_len = alloc_size;
	} else {
		LASSERT(req->rq_pool);
		LASSERT(req->rq_reqbuf_len >= msgsize);
		memset(req->rq_reqbuf, 0, msgsize);
	}

	req->rq_reqmsg = req->rq_reqbuf;
	return 0;
}

static
void null_free_reqbuf(struct ptlrpc_sec *sec,
		      struct ptlrpc_request *req)
{
	if (!req->rq_pool) {
		LASSERTF(req->rq_reqmsg == req->rq_reqbuf,
			 "req %p: reqmsg %p is not reqbuf %p in null sec\n",
			 req, req->rq_reqmsg, req->rq_reqbuf);
		LASSERTF(req->rq_reqbuf_len >= req->rq_reqlen,
			 "req %p: reqlen %d should smaller than buflen %d\n",
			 req, req->rq_reqlen, req->rq_reqbuf_len);

		kvfree(req->rq_reqbuf);
		req->rq_reqbuf = NULL;
		req->rq_reqbuf_len = 0;
	}
}

static
int null_alloc_repbuf(struct ptlrpc_sec *sec,
		      struct ptlrpc_request *req,
		      int msgsize)
{
	/* add space for early replied */
	msgsize += lustre_msg_early_size();

	msgsize = size_roundup_power2(msgsize);

	req->rq_repbuf = libcfs_kvzalloc(msgsize, GFP_NOFS);
	if (!req->rq_repbuf)
		return -ENOMEM;

	req->rq_repbuf_len = msgsize;
	return 0;
}

static
void null_free_repbuf(struct ptlrpc_sec *sec,
		      struct ptlrpc_request *req)
{
	LASSERT(req->rq_repbuf);

	kvfree(req->rq_repbuf);
	req->rq_repbuf = NULL;
	req->rq_repbuf_len = 0;
}

static
int null_enlarge_reqbuf(struct ptlrpc_sec *sec,
			struct ptlrpc_request *req,
			int segment, int newsize)
{
	struct lustre_msg *newbuf;
	struct lustre_msg *oldbuf = req->rq_reqmsg;
	int oldsize, newmsg_size, alloc_size;

	LASSERT(req->rq_reqbuf);
	LASSERT(req->rq_reqbuf == req->rq_reqmsg);
	LASSERT(req->rq_reqbuf_len >= req->rq_reqlen);
	LASSERT(req->rq_reqlen == lustre_packed_msg_size(oldbuf));

	/* compute new message size */
	oldsize = req->rq_reqbuf->lm_buflens[segment];
	req->rq_reqbuf->lm_buflens[segment] = newsize;
	newmsg_size = lustre_packed_msg_size(oldbuf);
	req->rq_reqbuf->lm_buflens[segment] = oldsize;

	/* request from pool should always have enough buffer */
	LASSERT(!req->rq_pool || req->rq_reqbuf_len >= newmsg_size);

	if (req->rq_reqbuf_len < newmsg_size) {
		alloc_size = size_roundup_power2(newmsg_size);

		newbuf = libcfs_kvzalloc(alloc_size, GFP_NOFS);
		if (!newbuf)
			return -ENOMEM;

		/* Must lock this, so that otherwise unprotected change of
		 * rq_reqmsg is not racing with parallel processing of
		 * imp_replay_list traversing threads. See LU-3333
		 * This is a bandaid at best, we really need to deal with this
		 * in request enlarging code before unpacking that's already
		 * there
		 */
		if (req->rq_import)
			spin_lock(&req->rq_import->imp_lock);
		memcpy(newbuf, req->rq_reqbuf, req->rq_reqlen);

		kvfree(req->rq_reqbuf);
		req->rq_reqbuf = newbuf;
		req->rq_reqmsg = newbuf;
		req->rq_reqbuf_len = alloc_size;

		if (req->rq_import)
			spin_unlock(&req->rq_import->imp_lock);
	}

	_sptlrpc_enlarge_msg_inplace(req->rq_reqmsg, segment, newsize);
	req->rq_reqlen = newmsg_size;

	return 0;
}

static struct ptlrpc_svc_ctx null_svc_ctx = {
	.sc_refcount    = ATOMIC_INIT(1),
	.sc_policy      = &null_policy,
};

static
int null_accept(struct ptlrpc_request *req)
{
	LASSERT(SPTLRPC_FLVR_POLICY(req->rq_flvr.sf_rpc) ==
		SPTLRPC_POLICY_NULL);

	if (req->rq_flvr.sf_rpc != SPTLRPC_FLVR_NULL) {
		CERROR("Invalid rpc flavor 0x%x\n", req->rq_flvr.sf_rpc);
		return SECSVC_DROP;
	}

	req->rq_sp_from = null_decode_sec_part(req->rq_reqbuf);

	req->rq_reqmsg = req->rq_reqbuf;
	req->rq_reqlen = req->rq_reqdata_len;

	req->rq_svc_ctx = &null_svc_ctx;
	atomic_inc(&req->rq_svc_ctx->sc_refcount);

	return SECSVC_OK;
}

static
int null_alloc_rs(struct ptlrpc_request *req, int msgsize)
{
	struct ptlrpc_reply_state *rs;
	int rs_size = sizeof(*rs) + msgsize;

	LASSERT(msgsize % 8 == 0);

	rs = req->rq_reply_state;

	if (rs) {
		/* pre-allocated */
		LASSERT(rs->rs_size >= rs_size);
	} else {
		rs = libcfs_kvzalloc(rs_size, GFP_NOFS);
		if (!rs)
			return -ENOMEM;

		rs->rs_size = rs_size;
	}

	rs->rs_svc_ctx = req->rq_svc_ctx;
	atomic_inc(&req->rq_svc_ctx->sc_refcount);

	rs->rs_repbuf = (struct lustre_msg *)(rs + 1);
	rs->rs_repbuf_len = rs_size - sizeof(*rs);
	rs->rs_msg = rs->rs_repbuf;

	req->rq_reply_state = rs;
	return 0;
}

static
void null_free_rs(struct ptlrpc_reply_state *rs)
{
	LASSERT_ATOMIC_GT(&rs->rs_svc_ctx->sc_refcount, 1);
	atomic_dec(&rs->rs_svc_ctx->sc_refcount);

	if (!rs->rs_prealloc)
		kvfree(rs);
}

static
int null_authorize(struct ptlrpc_request *req)
{
	struct ptlrpc_reply_state *rs = req->rq_reply_state;

	LASSERT(rs);

	rs->rs_repbuf->lm_secflvr = SPTLRPC_FLVR_NULL;
	rs->rs_repdata_len = req->rq_replen;

	if (likely(req->rq_packed_final)) {
		if (lustre_msghdr_get_flags(req->rq_reqmsg) & MSGHDR_AT_SUPPORT)
			req->rq_reply_off = lustre_msg_early_size();
		else
			req->rq_reply_off = 0;
	} else {
		__u32 cksum;

		cksum = lustre_msg_calc_cksum(rs->rs_repbuf);
		lustre_msg_set_cksum(rs->rs_repbuf, cksum);
		req->rq_reply_off = 0;
	}

	return 0;
}

static struct ptlrpc_ctx_ops null_ctx_ops = {
	.refresh		= null_ctx_refresh,
	.sign		   = null_ctx_sign,
	.verify		 = null_ctx_verify,
};

static struct ptlrpc_sec_cops null_sec_cops = {
	.create_sec	     = null_create_sec,
	.destroy_sec	    = null_destroy_sec,
	.lookup_ctx	     = null_lookup_ctx,
	.flush_ctx_cache	= null_flush_ctx_cache,
	.alloc_reqbuf	   = null_alloc_reqbuf,
	.alloc_repbuf	   = null_alloc_repbuf,
	.free_reqbuf	    = null_free_reqbuf,
	.free_repbuf	    = null_free_repbuf,
	.enlarge_reqbuf	 = null_enlarge_reqbuf,
};

static struct ptlrpc_sec_sops null_sec_sops = {
	.accept		 = null_accept,
	.alloc_rs	       = null_alloc_rs,
	.authorize	      = null_authorize,
	.free_rs		= null_free_rs,
};

static struct ptlrpc_sec_policy null_policy = {
	.sp_owner	       = THIS_MODULE,
	.sp_name		= "sec.null",
	.sp_policy	      = SPTLRPC_POLICY_NULL,
	.sp_cops		= &null_sec_cops,
	.sp_sops		= &null_sec_sops,
};

static void null_init_internal(void)
{
	static HLIST_HEAD(__list);

	null_sec.ps_policy = &null_policy;
	atomic_set(&null_sec.ps_refcount, 1);     /* always busy */
	null_sec.ps_id = -1;
	null_sec.ps_import = NULL;
	null_sec.ps_flvr.sf_rpc = SPTLRPC_FLVR_NULL;
	null_sec.ps_flvr.sf_flags = 0;
	null_sec.ps_part = LUSTRE_SP_ANY;
	null_sec.ps_dying = 0;
	spin_lock_init(&null_sec.ps_lock);
	atomic_set(&null_sec.ps_nctx, 1);	 /* for "null_cli_ctx" */
	INIT_LIST_HEAD(&null_sec.ps_gc_list);
	null_sec.ps_gc_interval = 0;
	null_sec.ps_gc_next = 0;

	hlist_add_head(&null_cli_ctx.cc_cache, &__list);
	atomic_set(&null_cli_ctx.cc_refcount, 1);    /* for hash */
	null_cli_ctx.cc_sec = &null_sec;
	null_cli_ctx.cc_ops = &null_ctx_ops;
	null_cli_ctx.cc_expire = 0;
	null_cli_ctx.cc_flags = PTLRPC_CTX_CACHED | PTLRPC_CTX_ETERNAL |
				PTLRPC_CTX_UPTODATE;
	null_cli_ctx.cc_vcred.vc_uid = 0;
	spin_lock_init(&null_cli_ctx.cc_lock);
	INIT_LIST_HEAD(&null_cli_ctx.cc_req_list);
	INIT_LIST_HEAD(&null_cli_ctx.cc_gc_chain);
}

int sptlrpc_null_init(void)
{
	int rc;

	null_init_internal();

	rc = sptlrpc_register_policy(&null_policy);
	if (rc)
		CERROR("failed to register %s: %d\n", null_policy.sp_name, rc);

	return rc;
}

void sptlrpc_null_fini(void)
{
	int rc;

	rc = sptlrpc_unregister_policy(&null_policy);
	if (rc)
		CERROR("failed to unregister %s: %d\n",
		       null_policy.sp_name, rc);
}