/*
   * 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/kernel.h>
  #include <net/sock.h>
  #include <linux/in.h>
  #include <linux/if_arp.h>

  #include <linux/jhash.h>

  #include <linux/ratelimit.h>

  #include "rds.h"

  static struct rhashtable bind_hash_table;

  static const struct rhashtable_params ht_parms = {

  	.nelem_hint = 768,
  	.key_len = sizeof(u64),
  	.key_offset = offsetof(struct rds_sock, rs_bound_key),
  	.head_offset = offsetof(struct rds_sock, rs_bound_node),
  	.max_size = 16384,
  	.min_size = 1024,

  };

  /*
   * Return the rds_sock bound at the given local address.
   *
   * The rx path can race with rds_release.  We notice if rds_release() has
   * marked this socket and don't return a rs ref to the rx path.
   */
  struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
  {

  	u64 key = ((u64)addr << 32) | port;

  	struct rds_sock *rs;

  	rcu_read_lock();
  	rs = rhashtable_lookup(&bind_hash_table, &key, ht_parms);

  	if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
  		rds_sock_addref(rs);
  	else

  		rs = NULL;

  	rcu_read_unlock();

  
  	rdsdebug("returning rs %p for %pI4:%u
  ", rs, &addr,
  		ntohs(port));

  	return rs;
  }
  
  /* returns -ve errno or +ve port */
  static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
  {

  	int ret = -EADDRINUSE;
  	u16 rover, last;

  	u64 key;

  
  	if (*port != 0) {
  		rover = be16_to_cpu(*port);

  		if (rover == RDS_FLAG_PROBE_PORT)
  			return -EINVAL;

  		last = rover;
  	} else {

  		rover = max_t(u16, prandom_u32(), 2);

  		last = rover - 1;
  	}

  	do {
  		if (rover == 0)
  			rover++;

  		if (rover == RDS_FLAG_PROBE_PORT)
  			continue;

  		key = ((u64)addr << 32) | cpu_to_be16(rover);
  		if (rhashtable_lookup_fast(&bind_hash_table, &key, ht_parms))
  			continue;
  
  		rs->rs_bound_key = key;
  		rs->rs_bound_addr = addr;

  		net_get_random_once(&rs->rs_hash_initval,
  				    sizeof(rs->rs_hash_initval));

  		rs->rs_bound_port = cpu_to_be16(rover);
  		rs->rs_bound_node.next = NULL;
  		rds_sock_addref(rs);
  		if (!rhashtable_insert_fast(&bind_hash_table,
  					    &rs->rs_bound_node, ht_parms)) {

  			*port = rs->rs_bound_port;

  			ret = 0;

  			rdsdebug("rs %p binding to %pI4:%d
  ",
  			  rs, &addr, (int)ntohs(*port));

  			break;

  		} else {

  			rs->rs_bound_addr = 0;

  			rds_sock_put(rs);
  			ret = -ENOMEM;
  			break;

  		}
  	} while (rover++ != last);

  	return ret;
  }
  
  void rds_remove_bound(struct rds_sock *rs)
  {

  	if (!rs->rs_bound_addr)
  		return;

  	rdsdebug("rs %p unbinding from %pI4:%d
  ",
  		 rs, &rs->rs_bound_addr,
  		 ntohs(rs->rs_bound_port));

  	rhashtable_remove_fast(&bind_hash_table, &rs->rs_bound_node, ht_parms);
  	rds_sock_put(rs);
  	rs->rs_bound_addr = 0;

  }
  
  int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sock *sk = sock->sk;
  	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
  	struct rds_sock *rs = rds_sk_to_rs(sk);
  	struct rds_transport *trans;
  	int ret = 0;
  
  	lock_sock(sk);
  
  	if (addr_len != sizeof(struct sockaddr_in) ||
  	    sin->sin_family != AF_INET ||
  	    rs->rs_bound_addr ||
  	    sin->sin_addr.s_addr == htonl(INADDR_ANY)) {
  		ret = -EINVAL;
  		goto out;
  	}

  	sock_set_flag(sk, SOCK_RCU_FREE);

  	ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port);
  	if (ret)
  		goto out;

  	if (rs->rs_transport) { /* previously bound */

  		trans = rs->rs_transport;
  		if (trans->laddr_check(sock_net(sock->sk),
  				       sin->sin_addr.s_addr) != 0) {
  			ret = -ENOPROTOOPT;
  			rds_remove_bound(rs);
  		} else {
  			ret = 0;
  		}

  		goto out;
  	}

  	trans = rds_trans_get_preferred(sock_net(sock->sk),
  					sin->sin_addr.s_addr);

  	if (!trans) {

  		ret = -EADDRNOTAVAIL;
  		rds_remove_bound(rs);

  		pr_info_ratelimited("RDS: %s could not find a transport for %pI4, load rds_tcp or rds_rdma?
  ",
  				    __func__, &sin->sin_addr.s_addr);

  		goto out;
  	}
  
  	rs->rs_transport = trans;
  	ret = 0;
  
  out:
  	release_sock(sk);
  	return ret;
  }

  void rds_bind_lock_destroy(void)

  {

  	rhashtable_destroy(&bind_hash_table);
  }

  int rds_bind_lock_init(void)
  {
  	return rhashtable_init(&bind_hash_table, &ht_parms);

  }