/*
   * Copyright (c) 2006 Oracle.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/gfp.h>
  #include <linux/in.h>
  #include <linux/poll.h>
  #include <net/sock.h>
  
  #include "rds.h"
  
  char *rds_str_array(char **array, size_t elements, size_t index)
  {
  	if ((index < elements) && array[index])
  		return array[index];
  	else
  		return "unknown";
  }
  EXPORT_SYMBOL(rds_str_array);
  
  /* this is just used for stats gathering :/ */
  static DEFINE_SPINLOCK(rds_sock_lock);
  static unsigned long rds_sock_count;
  static LIST_HEAD(rds_sock_list);
  DECLARE_WAIT_QUEUE_HEAD(rds_poll_waitq);
  
  /*
   * This is called as the final descriptor referencing this socket is closed.
   * We have to unbind the socket so that another socket can be bound to the
   * address it was using.
   *
   * We have to be careful about racing with the incoming path.  sock_orphan()
   * sets SOCK_DEAD and we use that as an indicator to the rx path that new
   * messages shouldn't be queued.
   */
  static int rds_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct rds_sock *rs;
  
  	if (!sk)
  		goto out;
  
  	rs = rds_sk_to_rs(sk);
  
  	sock_orphan(sk);
  	/* Note - rds_clear_recv_queue grabs rs_recv_lock, so
  	 * that ensures the recv path has completed messing
  	 * with the socket. */
  	rds_clear_recv_queue(rs);
  	rds_cong_remove_socket(rs);
  
  	/*
  	 * the binding lookup hash uses rcu, we need to
  	 * make sure we sychronize_rcu before we free our
  	 * entry
  	 */
  	rds_remove_bound(rs);
  	synchronize_rcu();
  
  	rds_send_drop_to(rs, NULL);
  	rds_rdma_drop_keys(rs);
  	rds_notify_queue_get(rs, NULL);
  
  	spin_lock_bh(&rds_sock_lock);
  	list_del_init(&rs->rs_item);
  	rds_sock_count--;
  	spin_unlock_bh(&rds_sock_lock);
  
  	rds_trans_put(rs->rs_transport);
  
  	sock->sk = NULL;
  	sock_put(sk);
  out:
  	return 0;
  }
  
  /*
   * Careful not to race with rds_release -> sock_orphan which clears sk_sleep.
   * _bh() isn't OK here, we're called from interrupt handlers.  It's probably OK
   * to wake the waitqueue after sk_sleep is clear as we hold a sock ref, but
   * this seems more conservative.
   * NB - normally, one would use sk_callback_lock for this, but we can
   * get here from interrupts, whereas the network code grabs sk_callback_lock
   * with _lock_bh only - so relying on sk_callback_lock introduces livelocks.
   */
  void rds_wake_sk_sleep(struct rds_sock *rs)
  {
  	unsigned long flags;
  
  	read_lock_irqsave(&rs->rs_recv_lock, flags);
  	__rds_wake_sk_sleep(rds_rs_to_sk(rs));
  	read_unlock_irqrestore(&rs->rs_recv_lock, flags);
  }
  
  static int rds_getname(struct socket *sock, struct sockaddr *uaddr,
  		       int *uaddr_len, int peer)
  {
  	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
  	struct rds_sock *rs = rds_sk_to_rs(sock->sk);
  
  	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
  
  	/* racey, don't care */
  	if (peer) {
  		if (!rs->rs_conn_addr)
  			return -ENOTCONN;
  
  		sin->sin_port = rs->rs_conn_port;
  		sin->sin_addr.s_addr = rs->rs_conn_addr;
  	} else {
  		sin->sin_port = rs->rs_bound_port;
  		sin->sin_addr.s_addr = rs->rs_bound_addr;
  	}
  
  	sin->sin_family = AF_INET;
  
  	*uaddr_len = sizeof(*sin);
  	return 0;
  }
  
  /*
   * RDS' poll is without a doubt the least intuitive part of the interface,
   * as POLLIN and POLLOUT do not behave entirely as you would expect from
   * a network protocol.
   *
   * POLLIN is asserted if
   *  -	there is data on the receive queue.
   *  -	to signal that a previously congested destination may have become
   *	uncongested
   *  -	A notification has been queued to the socket (this can be a congestion
   *	update, or a RDMA completion).
   *
   * POLLOUT is asserted if there is room on the send queue. This does not mean
   * however, that the next sendmsg() call will succeed. If the application tries
   * to send to a congested destination, the system call may still fail (and
   * return ENOBUFS).
   */
  static unsigned int rds_poll(struct file *file, struct socket *sock,
  			     poll_table *wait)
  {
  	struct sock *sk = sock->sk;
  	struct rds_sock *rs = rds_sk_to_rs(sk);
  	unsigned int mask = 0;
  	unsigned long flags;
  
  	poll_wait(file, sk_sleep(sk), wait);
  
  	if (rs->rs_seen_congestion)
  		poll_wait(file, &rds_poll_waitq, wait);
  
  	read_lock_irqsave(&rs->rs_recv_lock, flags);
  	if (!rs->rs_cong_monitor) {
  		/* When a congestion map was updated, we signal POLLIN for
  		 * "historical" reasons. Applications can also poll for
  		 * WRBAND instead. */
  		if (rds_cong_updated_since(&rs->rs_cong_track))
  			mask |= (POLLIN | POLLRDNORM | POLLWRBAND);
  	} else {
  		spin_lock(&rs->rs_lock);
  		if (rs->rs_cong_notify)
  			mask |= (POLLIN | POLLRDNORM);
  		spin_unlock(&rs->rs_lock);
  	}
  	if (!list_empty(&rs->rs_recv_queue) ||
  	    !list_empty(&rs->rs_notify_queue))
  		mask |= (POLLIN | POLLRDNORM);
  	if (rs->rs_snd_bytes < rds_sk_sndbuf(rs))
  		mask |= (POLLOUT | POLLWRNORM);
  	read_unlock_irqrestore(&rs->rs_recv_lock, flags);
  
  	/* clear state any time we wake a seen-congested socket */
  	if (mask)
  		rs->rs_seen_congestion = 0;
  
  	return mask;
  }
  
  static int rds_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
  {
  	return -ENOIOCTLCMD;
  }
  
  static int rds_cancel_sent_to(struct rds_sock *rs, char __user *optval,
  			      int len)
  {
  	struct sockaddr_in sin;
  	int ret = 0;
  
  	/* racing with another thread binding seems ok here */
  	if (rs->rs_bound_addr == 0) {
  		ret = -ENOTCONN; /* XXX not a great errno */
  		goto out;
  	}
  
  	if (len < sizeof(struct sockaddr_in)) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	if (copy_from_user(&sin, optval, sizeof(sin))) {
  		ret = -EFAULT;
  		goto out;
  	}
  
  	rds_send_drop_to(rs, &sin);
  out:
  	return ret;
  }
  
  static int rds_set_bool_option(unsigned char *optvar, char __user *optval,
  			       int optlen)
  {
  	int value;
  
  	if (optlen < sizeof(int))
  		return -EINVAL;
  	if (get_user(value, (int __user *) optval))
  		return -EFAULT;
  	*optvar = !!value;
  	return 0;
  }
  
  static int rds_cong_monitor(struct rds_sock *rs, char __user *optval,
  			    int optlen)
  {
  	int ret;
  
  	ret = rds_set_bool_option(&rs->rs_cong_monitor, optval, optlen);
  	if (ret == 0) {
  		if (rs->rs_cong_monitor) {
  			rds_cong_add_socket(rs);
  		} else {
  			rds_cong_remove_socket(rs);
  			rs->rs_cong_mask = 0;
  			rs->rs_cong_notify = 0;
  		}
  	}
  	return ret;
  }
  
  static int rds_setsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, unsigned int optlen)
  {
  	struct rds_sock *rs = rds_sk_to_rs(sock->sk);
  	int ret;
  
  	if (level != SOL_RDS) {
  		ret = -ENOPROTOOPT;
  		goto out;
  	}
  
  	switch (optname) {
  	case RDS_CANCEL_SENT_TO:
  		ret = rds_cancel_sent_to(rs, optval, optlen);
  		break;
  	case RDS_GET_MR:
  		ret = rds_get_mr(rs, optval, optlen);
  		break;
  	case RDS_GET_MR_FOR_DEST:
  		ret = rds_get_mr_for_dest(rs, optval, optlen);
  		break;
  	case RDS_FREE_MR:
  		ret = rds_free_mr(rs, optval, optlen);
  		break;
  	case RDS_RECVERR:
  		ret = rds_set_bool_option(&rs->rs_recverr, optval, optlen);
  		break;
  	case RDS_CONG_MONITOR:
  		ret = rds_cong_monitor(rs, optval, optlen);
  		break;
  	default:
  		ret = -ENOPROTOOPT;
  	}
  out:
  	return ret;
  }
  
  static int rds_getsockopt(struct socket *sock, int level, int optname,
  			  char __user *optval, int __user *optlen)
  {
  	struct rds_sock *rs = rds_sk_to_rs(sock->sk);
  	int ret = -ENOPROTOOPT, len;
  
  	if (level != SOL_RDS)
  		goto out;
  
  	if (get_user(len, optlen)) {
  		ret = -EFAULT;
  		goto out;
  	}
  
  	switch (optname) {
  	case RDS_INFO_FIRST ... RDS_INFO_LAST:
  		ret = rds_info_getsockopt(sock, optname, optval,
  					  optlen);
  		break;
  
  	case RDS_RECVERR:
  		if (len < sizeof(int))
  			ret = -EINVAL;
  		else
  		if (put_user(rs->rs_recverr, (int __user *) optval) ||
  		    put_user(sizeof(int), optlen))
  			ret = -EFAULT;
  		else
  			ret = 0;
  		break;
  	default:
  		break;
  	}
  
  out:
  	return ret;
  
  }
  
  static int rds_connect(struct socket *sock, struct sockaddr *uaddr,
  		       int addr_len, int flags)
  {
  	struct sock *sk = sock->sk;
  	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
  	struct rds_sock *rs = rds_sk_to_rs(sk);
  	int ret = 0;
  
  	lock_sock(sk);
  
  	if (addr_len != sizeof(struct sockaddr_in)) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	if (sin->sin_family != AF_INET) {
  		ret = -EAFNOSUPPORT;
  		goto out;
  	}
  
  	if (sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
  		ret = -EDESTADDRREQ;
  		goto out;
  	}
  
  	rs->rs_conn_addr = sin->sin_addr.s_addr;
  	rs->rs_conn_port = sin->sin_port;
  
  out:
  	release_sock(sk);
  	return ret;
  }
  
  static struct proto rds_proto = {
  	.name	  = "RDS",
  	.owner	  = THIS_MODULE,
  	.obj_size = sizeof(struct rds_sock),
  };
  
  static const struct proto_ops rds_proto_ops = {
  	.family =	AF_RDS,
  	.owner =	THIS_MODULE,
  	.release =	rds_release,
  	.bind =		rds_bind,
  	.connect =	rds_connect,
  	.socketpair =	sock_no_socketpair,
  	.accept =	sock_no_accept,
  	.getname =	rds_getname,
  	.poll =		rds_poll,
  	.ioctl =	rds_ioctl,
  	.listen =	sock_no_listen,
  	.shutdown =	sock_no_shutdown,
  	.setsockopt =	rds_setsockopt,
  	.getsockopt =	rds_getsockopt,
  	.sendmsg =	rds_sendmsg,
  	.recvmsg =	rds_recvmsg,
  	.mmap =		sock_no_mmap,
  	.sendpage =	sock_no_sendpage,
  };
  
  static int __rds_create(struct socket *sock, struct sock *sk, int protocol)
  {
  	struct rds_sock *rs;
  
  	sock_init_data(sock, sk);
  	sock->ops		= &rds_proto_ops;
  	sk->sk_protocol		= protocol;
  
  	rs = rds_sk_to_rs(sk);
  	spin_lock_init(&rs->rs_lock);
  	rwlock_init(&rs->rs_recv_lock);
  	INIT_LIST_HEAD(&rs->rs_send_queue);
  	INIT_LIST_HEAD(&rs->rs_recv_queue);
  	INIT_LIST_HEAD(&rs->rs_notify_queue);
  	INIT_LIST_HEAD(&rs->rs_cong_list);
  	spin_lock_init(&rs->rs_rdma_lock);
  	rs->rs_rdma_keys = RB_ROOT;
  
  	spin_lock_bh(&rds_sock_lock);
  	list_add_tail(&rs->rs_item, &rds_sock_list);
  	rds_sock_count++;
  	spin_unlock_bh(&rds_sock_lock);
  
  	return 0;
  }
  
  static int rds_create(struct net *net, struct socket *sock, int protocol,
  		      int kern)
  {
  	struct sock *sk;
  
  	if (sock->type != SOCK_SEQPACKET || protocol)
  		return -ESOCKTNOSUPPORT;
  
  	sk = sk_alloc(net, AF_RDS, GFP_ATOMIC, &rds_proto);
  	if (!sk)
  		return -ENOMEM;
  
  	return __rds_create(sock, sk, protocol);
  }
  
  void rds_sock_addref(struct rds_sock *rs)
  {
  	sock_hold(rds_rs_to_sk(rs));
  }
  
  void rds_sock_put(struct rds_sock *rs)
  {
  	sock_put(rds_rs_to_sk(rs));
  }
  
  static const struct net_proto_family rds_family_ops = {
  	.family =	AF_RDS,
  	.create =	rds_create,
  	.owner	=	THIS_MODULE,
  };
  
  static void rds_sock_inc_info(struct socket *sock, unsigned int len,
  			      struct rds_info_iterator *iter,
  			      struct rds_info_lengths *lens)
  {
  	struct rds_sock *rs;
  	struct rds_incoming *inc;
  	unsigned int total = 0;
  
  	len /= sizeof(struct rds_info_message);
  
  	spin_lock_bh(&rds_sock_lock);
  
  	list_for_each_entry(rs, &rds_sock_list, rs_item) {
  		read_lock(&rs->rs_recv_lock);
  
  		/* XXX too lazy to maintain counts.. */
  		list_for_each_entry(inc, &rs->rs_recv_queue, i_item) {
  			total++;
  			if (total <= len)
  				rds_inc_info_copy(inc, iter, inc->i_saddr,
  						  rs->rs_bound_addr, 1);
  		}
  
  		read_unlock(&rs->rs_recv_lock);
  	}
  
  	spin_unlock_bh(&rds_sock_lock);
  
  	lens->nr = total;
  	lens->each = sizeof(struct rds_info_message);
  }
  
  static void rds_sock_info(struct socket *sock, unsigned int len,
  			  struct rds_info_iterator *iter,
  			  struct rds_info_lengths *lens)
  {
  	struct rds_info_socket sinfo;
  	struct rds_sock *rs;
  
  	len /= sizeof(struct rds_info_socket);
  
  	spin_lock_bh(&rds_sock_lock);
  
  	if (len < rds_sock_count)
  		goto out;
  
  	list_for_each_entry(rs, &rds_sock_list, rs_item) {
  		sinfo.sndbuf = rds_sk_sndbuf(rs);
  		sinfo.rcvbuf = rds_sk_rcvbuf(rs);
  		sinfo.bound_addr = rs->rs_bound_addr;
  		sinfo.connected_addr = rs->rs_conn_addr;
  		sinfo.bound_port = rs->rs_bound_port;
  		sinfo.connected_port = rs->rs_conn_port;
  		sinfo.inum = sock_i_ino(rds_rs_to_sk(rs));
  
  		rds_info_copy(iter, &sinfo, sizeof(sinfo));
  	}
  
  out:
  	lens->nr = rds_sock_count;
  	lens->each = sizeof(struct rds_info_socket);
  
  	spin_unlock_bh(&rds_sock_lock);
  }
  
  static void rds_exit(void)
  {
  	sock_unregister(rds_family_ops.family);
  	proto_unregister(&rds_proto);
  	rds_conn_exit();
  	rds_cong_exit();
  	rds_sysctl_exit();
  	rds_threads_exit();
  	rds_stats_exit();
  	rds_page_exit();
  	rds_info_deregister_func(RDS_INFO_SOCKETS, rds_sock_info);
  	rds_info_deregister_func(RDS_INFO_RECV_MESSAGES, rds_sock_inc_info);
  }
  module_exit(rds_exit);
  
  static int rds_init(void)
  {
  	int ret;
  
  	ret = rds_conn_init();
  	if (ret)
  		goto out;
  	ret = rds_threads_init();
  	if (ret)
  		goto out_conn;
  	ret = rds_sysctl_init();
  	if (ret)
  		goto out_threads;
  	ret = rds_stats_init();
  	if (ret)
  		goto out_sysctl;
  	ret = proto_register(&rds_proto, 1);
  	if (ret)
  		goto out_stats;
  	ret = sock_register(&rds_family_ops);
  	if (ret)
  		goto out_proto;
  
  	rds_info_register_func(RDS_INFO_SOCKETS, rds_sock_info);
  	rds_info_register_func(RDS_INFO_RECV_MESSAGES, rds_sock_inc_info);
  
  	goto out;
  
  out_proto:
  	proto_unregister(&rds_proto);
  out_stats:
  	rds_stats_exit();
  out_sysctl:
  	rds_sysctl_exit();
  out_threads:
  	rds_threads_exit();
  out_conn:
  	rds_conn_exit();
  	rds_cong_exit();
  	rds_page_exit();
  out:
  	return ret;
  }
  module_init(rds_init);
  
  #define DRV_VERSION     "4.0"
  #define DRV_RELDATE     "Feb 12, 2009"
  
  MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
  MODULE_DESCRIPTION("RDS: Reliable Datagram Sockets"
  		   " v" DRV_VERSION " (" DRV_RELDATE ")");
  MODULE_VERSION(DRV_VERSION);
  MODULE_LICENSE("Dual BSD/GPL");
  MODULE_ALIAS_NETPROTO(PF_RDS);