/*
 * File: mhi_socket.c
 *
 * Copyright (C) 2011 Renesas Mobile Corporation. All rights reserved.
 *
 * Author: Petri Mattila <petri.to.mattila@renesasmobile.com>
 *
 * Socket layer implementation for AF_MHI.
 *
 * This module implements generic sockets for MHI.
 * The protocol is implemented separately, like mhi_dgram.c.
 *
 * As MHI does not have addressed, the MHI interface is
 * defined by sa_ifindex field in sockaddr_mhi.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 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 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 St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/net.h>
#include <linux/poll.h>
#include <linux/mhi.h>
#include <linux/l2mux.h>

#include <net/tcp_states.h>
#include <net/af_mhi.h>
#include <net/mhi/sock.h>
#include <net/mhi/dgram.h>
#include <net/mhi/raw.h>

#ifdef CONFIG_MHI_DEBUG
# define DPRINTK(...)    printk(KERN_DEBUG "MHI/SOCKET: " __VA_ARGS__)
#else
# define DPRINTK(...)
#endif


/* Master lock for MHI sockets */
static DEFINE_SPINLOCK(mhi_sock_lock);

/* List of MHI sockets */
static struct hlist_head mhi_sock_list;


static int mhi_sock_create(
	struct net		*net,
	struct socket		*sock,
	int			 proto,
	int			 kern)
{
	int err = 0;

	DPRINTK("mhi_sock_create: type:%d proto:%d\n",
		sock->type, proto);

	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_NET_ADMIN)) {
		printk(KERN_WARNING "AF_MHI: socket create failed: PERMISSION DENIED\n");
		return -EPERM;
	}

	if (!mhi_protocol_registered(proto)) {
		printk(KERN_WARNING "AF_MHI: socket create failed: No support for L2 channel %d\n",
					proto);
		return -EPROTONOSUPPORT;
	}

	if (sock->type == SOCK_DGRAM)
		err = mhi_dgram_sock_create(net, sock, proto, kern);
	else if (sock->type == SOCK_RAW)
		err = mhi_raw_sock_create(net, sock, proto, kern);
	else {
		printk(KERN_WARNING "AF_MHI: trying to create a socket with unknown type %d\n",
					sock->type);
		err = -EPROTONOSUPPORT;
	}

	if (err)
		printk(KERN_WARNING "AF_MHI: socket create failed: %d\n", err);

	return err;
}


static int mhi_sock_release(struct socket *sock)
{
	if (sock->sk) {
		DPRINTK("mhi_sock_release: proto:%d type:%d\n",
			sock->sk->sk_protocol, sock->type);

		sock->sk->sk_prot->close(sock->sk, 0);
		sock->sk = NULL;
	}

	return 0;
}

static int mhi_sock_bind(
	struct socket		*sock,
	struct sockaddr		*addr,
	int			len) {
	struct sock		*sk  = sock->sk;
	struct mhi_sock		*msk = mhi_sk(sk);
	struct sockaddr_mhi	*sam = sa_mhi(addr);

	int err = 0;

	DPRINTK("mhi_sock_bind: proto:%d state:%d\n",
		sk->sk_protocol, sk->sk_state);

	if (sk->sk_prot->bind)
		return sk->sk_prot->bind(sk, addr, len);

	if (len < sizeof(struct sockaddr_mhi))
		return -EINVAL;

	lock_sock(sk);
	{
		if (sk->sk_state == TCP_CLOSE) {
			msk->sk_ifindex = sam->sa_ifindex;
			WARN_ON(sk_hashed(sk));
			sk->sk_prot->hash(sk);
		} else {
			err = -EINVAL; /* attempt to rebind */
		}
	}
	release_sock(sk);

	return err;
}

int mhi_sock_rcv_unicast(
	struct sk_buff     *skb,
	u8                  l3proto,
	u32                 l3length)
{
	struct sock        *sknode;
	struct mhi_sock	   *msk;

	DPRINTK("%s: proto:%d, len:%d\n", l3proto, l3length, __func__);

	spin_lock(&mhi_sock_lock);
	{
		sk_for_each(sknode, &mhi_sock_list) {
			msk = mhi_sk(sknode);
			if ((msk->sk_l3proto == MHI_L3_ANY ||
			      msk->sk_l3proto == l3proto) &&
			     (msk->sk_ifindex == skb->dev->ifindex)) {
				sock_hold(sknode);
				sk_receive_skb(sknode, skb, 0);
				skb = NULL;
				break;
			}
		}
	}
	spin_unlock(&mhi_sock_lock);

	if (skb)
		kfree_skb(skb);

	return NET_RX_SUCCESS;
}

int mhi_sock_rcv_multicast(
	struct sk_buff     *skb,
	u8                  l3proto,
	u32                 l3length)
{
	struct sock        *sknode;
	struct mhi_sock	   *msk;
	struct sk_buff     *clone;

	DPRINTK("%s: proto:%d, len:%d\n", l3proto, l3length, __func__);

	spin_lock(&mhi_sock_lock);
	{
		sk_for_each(sknode, &mhi_sock_list) {
			msk = mhi_sk(sknode);
			if ((msk->sk_l3proto == MHI_L3_ANY ||
			      msk->sk_l3proto == l3proto) &&
			     (msk->sk_ifindex == skb->dev->ifindex)) {
				clone = skb_clone(skb, GFP_ATOMIC);
				if (likely(clone)) {
					sock_hold(sknode);
					sk_receive_skb(sknode, clone, 0);
				}
			}
		}
	}
	spin_unlock(&mhi_sock_lock);

	kfree_skb(skb);

	return NET_RX_SUCCESS;
}

int mhi_sock_sendmsg(
	struct kiocb	*iocb,
	struct socket	*sock,
	struct msghdr	*msg,
	size_t		 len)
{
	DPRINTK("mhi_sock_sendmsg: len:%lu\n", len);
	return sock->sk->sk_prot->sendmsg(iocb, sock->sk, msg, len);
}

int mhi_sock_recvmsg(
	struct kiocb    *iocb,
	struct socket   *sock,
	struct msghdr   *msg,
	size_t           len,
	int              flags)
{
	int addrlen = 0;
	int err;

	err = sock->sk->sk_prot->recvmsg(iocb, sock->sk, msg, len,
					 flags & MSG_DONTWAIT,
					 flags & ~MSG_DONTWAIT,
					 &addrlen);

	if (err >= 0)
		msg->msg_namelen = addrlen;

	return err;
}


void mhi_sock_hash(struct sock *sk)
{
	DPRINTK("mhi_sock_hash: proto:%d\n", sk->sk_protocol);

	spin_lock_bh(&mhi_sock_lock);
	sk_add_node(sk, &mhi_sock_list);
	spin_unlock_bh(&mhi_sock_lock);
}

void mhi_sock_unhash(struct sock *sk)
{
	DPRINTK("mhi_sock_unhash: proto:%d\n", sk->sk_protocol);

	spin_lock_bh(&mhi_sock_lock);
	sk_del_node_init(sk);
	spin_unlock_bh(&mhi_sock_lock);
}


const struct proto_ops mhi_socket_ops = {
	.family		= AF_MHI,
	.owner		= THIS_MODULE,
	.release	= mhi_sock_release,
	.bind		= mhi_sock_bind,
	.connect	= sock_no_connect,
	.socketpair	= sock_no_socketpair,
	.accept		= sock_no_accept,
	.getname	= sock_no_getname,
	.poll		= datagram_poll,
	.ioctl		= sock_no_ioctl,
	.listen		= sock_no_listen,
	.shutdown	= sock_no_shutdown,
	.setsockopt	= sock_no_setsockopt,
	.getsockopt	= sock_no_getsockopt,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = sock_no_setsockopt,
	.compat_getsockopt = sock_no_getsockopt,
#endif
	.sendmsg	= mhi_sock_sendmsg,
	.recvmsg	= mhi_sock_recvmsg,
	.mmap		= sock_no_mmap,
	.sendpage	= sock_no_sendpage,
};

static const struct net_proto_family mhi_proto_family = {
	.family = PF_MHI,
	.create = mhi_sock_create,
	.owner  = THIS_MODULE,
};


int mhi_sock_init(void)
{
	DPRINTK("mhi_sock_init\n");

	INIT_HLIST_HEAD(&mhi_sock_list);
	spin_lock_init(&mhi_sock_lock);

	return sock_register(&mhi_proto_family);
}

void mhi_sock_exit(void)
{
	DPRINTK("mhi_sock_exit\n");

	sock_unregister(PF_MHI);
}