/*
 * Driver for /dev/crypto device (aka CryptoDev)
 *
 * Copyright (c) 2004 Michal Ludvig <mludvig@logix.net.nz>, SuSE Labs
 * Copyright (c) 2009,2010 Nikos Mavrogiannopoulos <nmav@gnutls.org>
 *
 * This file is part of linux cryptodev.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/* #include <linux/highmem.h> */
/* #include <linux/ioctl.h> */
/* #include <linux/random.h> */
/* #include <linux/syscalls.h> */
/* #include <linux/uaccess.h> */
/* #include "cryptodev_int.h" */
/* #include <linux/version.h> */
#include <linux/crypto.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/pagemap.h>
#include <linux/scatterlist.h>
#include <net/sock.h>
#include "alg.h"
#include "ncr-int.h"

MODULE_AUTHOR("Nikos Mavrogiannopoulos <nmav@gnutls.org>");
MODULE_DESCRIPTION("CryptoDev driver");
MODULE_LICENSE("GPL");

/* ====== Module parameters ====== */

int cryptodev_verbosity = 0;
module_param(cryptodev_verbosity, int, 0644);
MODULE_PARM_DESC(cryptodev_verbosity, "0: normal, 1: verbose, 2: debug");

/* ====== CryptoAPI ====== */

void release_user_pages(struct page **pg, int pagecount)
{
	while (pagecount--) {
		if (!PageReserved(pg[pagecount]))
			SetPageDirty(pg[pagecount]);
		page_cache_release(pg[pagecount]);
	}
}

/* offset of buf in it's first page */
#define PAGEOFFSET(buf) ((unsigned long)buf & ~PAGE_MASK)

/* fetch the pages addr resides in into pg and initialise sg with them */
int __get_userbuf(uint8_t __user * addr, uint32_t len, int write,
		  int pgcount, struct page **pg, struct scatterlist *sg)
{
	int ret, pglen, i = 0;
	struct scatterlist *sgp;

	down_write(&current->mm->mmap_sem);
	ret = get_user_pages(current, current->mm,
			     (unsigned long)addr, pgcount, write, 0, pg, NULL);
	up_write(&current->mm->mmap_sem);
	if (ret != pgcount)
		return -EINVAL;

	sg_init_table(sg, pgcount);

	pglen =
	    min((ptrdiff_t) (PAGE_SIZE - PAGEOFFSET(addr)), (ptrdiff_t) len);
	sg_set_page(sg, pg[i++], pglen, PAGEOFFSET(addr));

	len -= pglen;
	for (sgp = sg_next(sg); len; sgp = sg_next(sgp)) {
		pglen = min((uint32_t) PAGE_SIZE, len);
		sg_set_page(sgp, pg[i++], pglen, 0);
		len -= pglen;
	}
	sg_mark_end(sg_last(sg, pgcount));
	return 0;
}

/* ====== /dev/crypto ====== */

struct alg_sock {
	struct sock sk;
	struct sockaddr_alg addr;
	struct sock *queued;
	struct hash_data hash;
};

static struct alg_sock *alg_sk(struct sock *sk)
{
	return container_of(sk, struct alg_sock, sk);
}

static struct proto alg_proto = {
/* 	void			(*close)(struct sock *sk,  */
/* 					long timeout); */
/* 	int			(*connect)(struct sock *sk, */
/* 				        struct sockaddr *uaddr,  */
/* 					int addr_len); */
/* 	int			(*disconnect)(struct sock *sk, int flags); */

/* 	struct sock *		(*accept) (struct sock *sk, int flags, int *err); */

/* 	int			(*ioctl)(struct sock *sk, int cmd, */
/* 					 unsigned long arg); */
/* 	int			(*init)(struct sock *sk); */
/* 	void			(*destroy)(struct sock *sk); */
/* 	void			(*shutdown)(struct sock *sk, int how); */
/* 	int			(*setsockopt)(struct sock *sk, int level,  */
/* 					int optname, char __user *optval, */
/* 					unsigned int optlen); */
/* 	int			(*getsockopt)(struct sock *sk, int level,  */
/* 					int optname, char __user *optval,  */
/* 					int __user *option);  	  */
/* #ifdef CONFIG_COMPAT */
/* 	int			(*compat_setsockopt)(struct sock *sk, */
/* 					int level, */
/* 					int optname, char __user *optval, */
/* 					unsigned int optlen); */
/* 	int			(*compat_getsockopt)(struct sock *sk, */
/* 					int level, */
/* 					int optname, char __user *optval, */
/* 					int __user *option); */
/* #endif */
/* 	int			(*sendmsg)(struct kiocb *iocb, struct sock *sk, */
/* 					   struct msghdr *msg, size_t len); */
/* 	int			(*recvmsg)(struct kiocb *iocb, struct sock *sk, */
/* 					   struct msghdr *msg, */
/* 					size_t len, int noblock, int flags,  */
/* 					int *addr_len); */
/* 	int			(*sendpage)(struct sock *sk, struct page *page, */
/* 					int offset, size_t size, int flags); */
/* 	int			(*bind)(struct sock *sk,  */
/* 					struct sockaddr *uaddr, int addr_len); */

/* 	int			(*backlog_rcv) (struct sock *sk,  */
/* 						struct sk_buff *skb); */

/* 	/\* Keeping track of sk's, looking them up, and port selection methods. *\/ */
/* 	void			(*hash)(struct sock *sk); */
/* 	void			(*unhash)(struct sock *sk); */
/* 	int			(*get_port)(struct sock *sk, unsigned short snum); */

/* 	/\* Keeping track of sockets in use *\/ */
/* #ifdef CONFIG_PROC_FS */
/* 	unsigned int		inuse_idx; */
/* #endif */

/* 	/\* Memory pressure *\/ */
/* 	void			(*enter_memory_pressure)(struct sock *sk); */
/* 	atomic_t		*memory_allocated;	/\* Current allocated memory. *\/ */
/* 	struct percpu_counter	*sockets_allocated;	/\* Current number of sockets. *\/ */
/* 	/\* */
/* 	 * Pressure flag: try to collapse. */
/* 	 * Technical note: it is used by multiple contexts non atomically. */
/* 	 * All the __sk_mem_schedule() is of this nature: accounting */
/* 	 * is strict, actions are advisory and have some latency. */
/* 	 *\/ */
/* 	int			*memory_pressure; */
/* 	int			*sysctl_mem; */
/* 	int			*sysctl_wmem; */
/* 	int			*sysctl_rmem; */
/* 	int			max_header; */

	.obj_size = sizeof(struct alg_sock),
/* 	int			slab_flags; */

/* 	struct percpu_counter	*orphan_count; */

/* 	struct request_sock_ops	*rsk_prot; */
/* 	struct timewait_sock_ops *twsk_prot; */

/* 	union { */
/* 		struct inet_hashinfo	*hashinfo; */
/* 		struct udp_table	*udp_table; */
/* 		struct raw_hashinfo	*raw_hash; */
/* 	} h; */

 	.owner = THIS_MODULE,
	.name = "ALG",

/* 	struct list_head	node; */
/* #ifdef SOCK_REFCNT_DEBUG */
/* 	atomic_t		socks; */
/* #endif */
};

static int alg_release(struct socket *sock)
{
	struct sock *sk;
	struct alg_sock *ask;

	sk = sock->sk;
	if (sk == NULL)
		return 0;

	sock->sk = NULL;

	// skb_queue_purge(&sk->sk_write_queue);???

	ask = alg_sk(sk);
	if (ask->queued != NULL) {
		local_bh_disable();
		sock_prot_inuse_add(sock_net(ask->queued), &alg_proto, -1);
		local_bh_enable();
		sock_put(ask->queued);
	}

	if (ask->hash.init != 0)
		cryptodev_hash_deinit(&ask->hash);

	local_bh_disable();
	sock_prot_inuse_add(sock_net(sk), &alg_proto, -1);
	local_bh_enable();

	sock_put(sk);
	return 0;
}

static int alg_bind(struct socket *sock, struct sockaddr *myaddr,
		    int sockaddr_len)
{
	struct sockaddr_alg *addr;
	struct alg_sock *ask;

	if (myaddr->sa_family != AF_ALG || sockaddr_len < sizeof(*addr))
		return -EINVAL;
	addr = (struct sockaddr_alg *)myaddr;

	// FIXME: locking

	// FIXME
	if (strncmp(addr->salg_type, "hash", sizeof(addr->salg_type)) != 0)
		return -EINVAL;

	ask = alg_sk(sock->sk);
	ask->addr = *addr;
	return 0;
}

static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct alg_sock *ask;
	struct sock *newsk;

	// FIXME: locking
	ask = alg_sk(sock->sk);
	if (ask->queued == NULL)
		return -EINVAL;

	newsk = ask->queued;
	ask->queued = NULL;
	sock_graft(newsk, newsock);
	return 0;
}

static int alg_listen(struct socket *sock, int len)
{
	struct net *net;
	struct sock *newsk;
	struct alg_sock *ask, *newask;
	int res;

	// FIXME: locking
	net = sock_net(sock->sk);
	ask = alg_sk(sock->sk);
	if (ask->addr.salg_type[0] == 0)
		return -EINVAL; // FIXME: better error code for "not bound"?
	// FIXME: type-specific
	if (len != 1)
		return -EINVAL;

	if (ask->queued != NULL)
		return -EINVAL;

	newsk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
	if (newsk == NULL)
		return -ENOMEM;
	newask = alg_sk(newsk);
	// FIXME
	res = cryptodev_hash_init(&newask->hash, ask->addr.salg_tfm, NULL, 0);
	if (res != 0) {
		sock_put(newsk);
		return res;
	}

	sock_init_data(NULL, newsk);
	local_bh_disable();
	sock_prot_inuse_add(net, &alg_proto, 1);
	local_bh_enable();

	ask->queued = newsk;

	return 0;
}

static int alg_sendmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len)
{
	struct alg_sock *ask;
	char *buf;
	int res;

	// FIXME: locking
	ask = alg_sk(sock->sk);
	if (ask->hash.init == 0)
		return -EINVAL;

	// FIXME: limit size, or use socket buffer
	buf = kmalloc(total_len, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	res = memcpy_fromiovec(buf, m->msg_iov, total_len);
	if (res != 0)
		goto err;

	// FIXME
	res = _cryptodev_hash_update(&ask->hash, buf, total_len);
	if (res < 0)
		goto err;

	res = total_len;

err:
	kfree(buf);
	return res;
}

static int alg_recvmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *m, size_t total_len, int flags)
{
	char digest[NCR_HASH_MAX_OUTPUT_SIZE];
	struct alg_sock *ask;
	int res;

	// FIXME: locking
	ask = alg_sk(sock->sk);
	if (ask->hash.init == 0)
		return -EINVAL;
	if (total_len < ask->hash.digestsize)
		return -EINVAL;

	// FIXME
	BUG_ON(ask->hash.digestsize > sizeof(digest));
	res = cryptodev_hash_final(&ask->hash, digest);
	if (res < 0)
		return res;

	res = memcpy_toiovec(m->msg_iov, digest, ask->hash.digestsize);
	if (res != 0)
		return res;

	res = cryptodev_hash_reset(&ask->hash);
	if (res != 0)
		return res;

	return ask->hash.digestsize;
}

static const struct proto_ops alg_proto_ops = {
	.family = PF_ALG,
	.owner = THIS_MODULE,
	.release = alg_release,
	.bind = alg_bind,
	.connect = sock_no_connect,
	.socketpair = sock_no_socketpair,
	.accept = alg_accept,
	.getname = sock_no_getname,
	.poll = sock_no_poll,
	.ioctl = sock_no_ioctl,
	.compat_ioctl = NULL,
	.listen = alg_listen,
	.shutdown = sock_no_shutdown,
	.setsockopt = sock_no_setsockopt,
	.getsockopt = sock_no_getsockopt,
	.compat_setsockopt = NULL,
	.compat_getsockopt = NULL,
	.sendmsg = alg_sendmsg,
	.recvmsg = alg_recvmsg,
	.mmap = sock_no_mmap,
	.sendpage = NULL,
	.splice_read = NULL,
};

static int alg_create(struct net *net, struct socket *sock, int protocol,
		      int kern)
{
	struct sock *sk;

	if (sock->type != SOCK_STREAM)
		return -ESOCKTNOSUPPORT;
	if (protocol != 0)
		return -EPROTONOSUPPORT;

	sock->ops = &alg_proto_ops;

	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
	if (sk == NULL)
		return -ENOMEM;

	sock_init_data(sock, sk);

	local_bh_disable();
	sock_prot_inuse_add(net, &alg_proto, 1);
	local_bh_enable();

	return 0;
}

static const struct net_proto_family alg_pf = {
	.family = PF_ALG,
	.create = alg_create,
	.owner = THIS_MODULE
};

static int __init cryptodev_register(void)
{
	int rc;

	ncr_limits_init();
	ncr_master_key_reset();

	rc = proto_register(&alg_proto, 1);
	if (unlikely(rc != 0))
		goto err_limits;

	rc = sock_register(&alg_pf);
	if (unlikely(rc != 0))
		goto err_proto;

	return 0;

err_proto:
	proto_unregister(&alg_proto);
err_limits:
	ncr_limits_deinit();
	printk(KERN_ERR PFX "registration of /dev/crypto failed\n");
	return rc;
}

static void __exit cryptodev_deregister(void)
{
	sock_unregister(PF_ALG);
	proto_unregister(&alg_proto);
	ncr_limits_deinit();
}

/* ====== Module init/exit ====== */
static int __init init_cryptodev(void)
{
	int rc;

	rc = cryptodev_register();
	if (unlikely(rc))
		return rc;

	printk(KERN_INFO PFX "driver loaded.\n");

	return 0;
}

static void __exit exit_cryptodev(void)
{
	cryptodev_deregister();
	printk(KERN_INFO PFX "driver unloaded.\n");
}

module_init(init_cryptodev);
module_exit(exit_cryptodev);