text: /*
   * Copyright (c) 2010 Voltaire Inc.  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.
   */
  
  #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
  
  #include <linux/export.h>
  #include <net/netlink.h>
  #include <net/net_namespace.h>
  #include <net/sock.h>
  #include <rdma/rdma_netlink.h>
  
  struct ibnl_client {
  	struct list_head		list;
  	int				index;
  	int				nops;
  	const struct ibnl_client_cbs   *cb_table;
  };
  
  static DEFINE_MUTEX(ibnl_mutex);
  static struct sock *nls;
  static LIST_HEAD(client_list);
  
  int ibnl_add_client(int index, int nops,
  		    const struct ibnl_client_cbs cb_table[])
  {
  	struct ibnl_client *cur;
  	struct ibnl_client *nl_client;
  
  	nl_client = kmalloc(sizeof *nl_client, GFP_KERNEL);
  	if (!nl_client)
  		return -ENOMEM;
  
  	nl_client->index	= index;
  	nl_client->nops		= nops;
  	nl_client->cb_table	= cb_table;
  
  	mutex_lock(&ibnl_mutex);
  
  	list_for_each_entry(cur, &client_list, list) {
  		if (cur->index == index) {
  			pr_warn("Client for %d already exists\n", index);
  			mutex_unlock(&ibnl_mutex);
  			kfree(nl_client);
  			return -EINVAL;
  		}
  	}
  
  	list_add_tail(&nl_client->list, &client_list);
  
  	mutex_unlock(&ibnl_mutex);
  
  	return 0;
  }
  EXPORT_SYMBOL(ibnl_add_client);
  
  int ibnl_remove_client(int index)
  {
  	struct ibnl_client *cur, *next;
  
  	mutex_lock(&ibnl_mutex);
  	list_for_each_entry_safe(cur, next, &client_list, list) {
  		if (cur->index == index) {
  			list_del(&(cur->list));
  			mutex_unlock(&ibnl_mutex);
  			kfree(cur);
  			return 0;
  		}
  	}
  	pr_warn("Can't remove callback for client idx %d. Not found\n", index);
  	mutex_unlock(&ibnl_mutex);
  
  	return -EINVAL;
  }
  EXPORT_SYMBOL(ibnl_remove_client);
  
  void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
  		   int len, int client, int op)
  {
  	unsigned char *prev_tail;
  
  	prev_tail = skb_tail_pointer(skb);
  	*nlh = NLMSG_NEW(skb, 0, seq, RDMA_NL_GET_TYPE(client, op),
  			len, NLM_F_MULTI);
  	(*nlh)->nlmsg_len = skb_tail_pointer(skb) - prev_tail;
  	return NLMSG_DATA(*nlh);
  
  nlmsg_failure:
  	nlmsg_trim(skb, prev_tail);
  	return NULL;
  }
  EXPORT_SYMBOL(ibnl_put_msg);
  
  int ibnl_put_attr(struct sk_buff *skb, struct nlmsghdr *nlh,
  		  int len, void *data, int type)
  {
  	unsigned char *prev_tail;
  
  	prev_tail = skb_tail_pointer(skb);
  	NLA_PUT(skb, type, len, data);
  	nlh->nlmsg_len += skb_tail_pointer(skb) - prev_tail;
  	return 0;
  
  nla_put_failure:
  	nlmsg_trim(skb, prev_tail - nlh->nlmsg_len);
  	return -EMSGSIZE;
  }
  EXPORT_SYMBOL(ibnl_put_attr);
  
  static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	struct ibnl_client *client;
  	int type = nlh->nlmsg_type;
  	int index = RDMA_NL_GET_CLIENT(type);
  	int op = RDMA_NL_GET_OP(type);
  
  	list_for_each_entry(client, &client_list, list) {
  		if (client->index == index) {
  			if (op < 0 || op >= client->nops ||
  			    !client->cb_table[RDMA_NL_GET_OP(op)].dump)
  				return -EINVAL;
  			return netlink_dump_start(nls, skb, nlh,
  						  client->cb_table[op].dump,
  						  NULL, 0);
  		}
  	}
  
  	pr_info("Index %d wasn't found in client list\n", index);
  	return -EINVAL;
  }
  
  static void ibnl_rcv(struct sk_buff *skb)
  {
  	mutex_lock(&ibnl_mutex);
  	netlink_rcv_skb(skb, &ibnl_rcv_msg);
  	mutex_unlock(&ibnl_mutex);
  }
  
  int __init ibnl_init(void)
  {
  	nls = netlink_kernel_create(&init_net, NETLINK_RDMA, 0, ibnl_rcv,
  				    NULL, THIS_MODULE);
  	if (!nls) {
  		pr_warn("Failed to create netlink socket\n");
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  void ibnl_cleanup(void)
  {
  	struct ibnl_client *cur, *next;
  
  	mutex_lock(&ibnl_mutex);
  	list_for_each_entry_safe(cur, next, &client_list, list) {
  		list_del(&(cur->list));
  		kfree(cur);
  	}
  	mutex_unlock(&ibnl_mutex);
  
  	netlink_kernel_release(nls);
  }
  