/*

   * Copyright (c) 2006, 2019 Oracle and/or its affiliates. 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/ipv6.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 = RDS_BOUND_KEY_LEN,

  	.key_offset = offsetof(struct rds_sock, rs_bound_key),
  	.head_offset = offsetof(struct rds_sock, rs_bound_node),
  	.max_size = 16384,
  	.min_size = 1024,

  };

  /* Create a key for the bind hash table manipulation.  Port is in network byte
   * order.
   */
  static inline void __rds_create_bind_key(u8 *key, const struct in6_addr *addr,
  					 __be16 port, __u32 scope_id)
  {
  	memcpy(key, addr, sizeof(*addr));
  	key += sizeof(*addr);
  	memcpy(key, &port, sizeof(port));
  	key += sizeof(port);
  	memcpy(key, &scope_id, sizeof(scope_id));
  }

  /*
   * 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(const struct in6_addr *addr, __be16 port,
  				__u32 scope_id)

  {

  	u8 key[RDS_BOUND_KEY_LEN];

  	struct rds_sock *rs;

  	__rds_create_bind_key(key, addr, port, scope_id);

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

  	if (rs && (sock_flag(rds_rs_to_sk(rs), SOCK_DEAD) ||
  		   !refcount_inc_not_zero(&rds_rs_to_sk(rs)->sk_refcnt)))

  		rs = NULL;

  	rcu_read_unlock();

  	rdsdebug("returning rs %p for %pI6c:%u
  ", rs, addr,
  		 ntohs(port));

  	return rs;
  }
  
  /* returns -ve errno or +ve port */

  static int rds_add_bound(struct rds_sock *rs, const struct in6_addr *addr,
  			 __be16 *port, __u32 scope_id)

  {

  	int ret = -EADDRINUSE;
  	u16 rover, last;

  	u8 key[RDS_BOUND_KEY_LEN];

  
  	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;

  		__rds_create_bind_key(key, addr, cpu_to_be16(rover),
  				      scope_id);
  		if (rhashtable_lookup_fast(&bind_hash_table, key, ht_parms))

  			continue;

  		memcpy(rs->rs_bound_key, key, sizeof(rs->rs_bound_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;

  			rs->rs_bound_scope_id = scope_id;

  			ret = 0;

  			rdsdebug("rs %p binding to %pI6c:%d
  ",
  				 rs, addr, (int)ntohs(*port));

  			break;

  		} else {

  			rs->rs_bound_addr = in6addr_any;

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

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

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

  	if (ipv6_addr_any(&rs->rs_bound_addr))

  		return;

  	rdsdebug("rs %p unbinding from %pI6c:%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 = in6addr_any;

  }
  
  int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
  {
  	struct sock *sk = sock->sk;

  	struct rds_sock *rs = rds_sk_to_rs(sk);

  	struct in6_addr v6addr, *binding_addr;

  	struct rds_transport *trans;

  	__u32 scope_id = 0;

  	int ret = 0;

  	__be16 port;

  	/* We allow an RDS socket to be bound to either IPv4 or IPv6
  	 * address.

  	 */

  	if (addr_len < offsetofend(struct sockaddr, sa_family))
  		return -EINVAL;

  	if (uaddr->sa_family == AF_INET) {

  		struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;

  		if (addr_len < sizeof(struct sockaddr_in) ||
  		    sin->sin_addr.s_addr == htonl(INADDR_ANY) ||
  		    sin->sin_addr.s_addr == htonl(INADDR_BROADCAST) ||

  		    ipv4_is_multicast(sin->sin_addr.s_addr))

  			return -EINVAL;
  		ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, &v6addr);
  		binding_addr = &v6addr;
  		port = sin->sin_port;

  #if IS_ENABLED(CONFIG_IPV6)

  	} else if (uaddr->sa_family == AF_INET6) {
  		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)uaddr;

  		int addr_type;

  
  		if (addr_len < sizeof(struct sockaddr_in6))
  			return -EINVAL;
  		addr_type = ipv6_addr_type(&sin6->sin6_addr);
  		if (!(addr_type & IPV6_ADDR_UNICAST)) {
  			__be32 addr4;
  
  			if (!(addr_type & IPV6_ADDR_MAPPED))
  				return -EINVAL;
  
  			/* It is a mapped address.  Need to do some sanity
  			 * checks.
  			 */
  			addr4 = sin6->sin6_addr.s6_addr32[3];
  			if (addr4 == htonl(INADDR_ANY) ||
  			    addr4 == htonl(INADDR_BROADCAST) ||

  			    ipv4_is_multicast(addr4))

  				return -EINVAL;
  		}
  		/* The scope ID must be specified for link local address. */
  		if (addr_type & IPV6_ADDR_LINKLOCAL) {
  			if (sin6->sin6_scope_id == 0)
  				return -EINVAL;
  			scope_id = sin6->sin6_scope_id;
  		}
  		binding_addr = &sin6->sin6_addr;
  		port = sin6->sin6_port;

  #endif

  	} else {
  		return -EINVAL;
  	}

  	lock_sock(sk);

  	/* RDS socket does not allow re-binding. */
  	if (!ipv6_addr_any(&rs->rs_bound_addr)) {

  		ret = -EINVAL;
  		goto out;
  	}

  	/* Socket is connected.  The binding address should have the same
  	 * scope ID as the connected address, except the case when one is
  	 * non-link local address (scope_id is 0).
  	 */
  	if (!ipv6_addr_any(&rs->rs_conn_addr) && scope_id &&
  	    rs->rs_bound_scope_id &&
  	    scope_id != rs->rs_bound_scope_id) {
  		ret = -EINVAL;
  		goto out;
  	}

  	/* The transport can be set using SO_RDS_TRANSPORT option before the
  	 * socket is bound.
  	 */
  	if (rs->rs_transport) {

  		trans = rs->rs_transport;

  		if (!trans->laddr_check ||
  		    trans->laddr_check(sock_net(sock->sk),

  				       binding_addr, scope_id) != 0) {

  			ret = -ENOPROTOOPT;

  			goto out;

  		}

  	} else {
  		trans = rds_trans_get_preferred(sock_net(sock->sk),
  						binding_addr, scope_id);
  		if (!trans) {
  			ret = -EADDRNOTAVAIL;
  			pr_info_ratelimited("RDS: %s could not find a transport for %pI6c, load rds_tcp or rds_rdma?
  ",
  					    __func__, binding_addr);
  			goto out;
  		}
  		rs->rs_transport = trans;

  	}

  	sock_set_flag(sk, SOCK_RCU_FREE);
  	ret = rds_add_bound(rs, binding_addr, &port, scope_id);

  	if (ret)
  		rs->rs_transport = NULL;

  
  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);

  }